Radiation curable compositions for coating optical fibers and coatings produced therefrom

文档序号：927540 发布日期：2021-03-02 浏览：9次中文

阅读说明：本技术 用于涂覆光纤的辐射可固化组合物及由其生产的涂层 (Radiation curable compositions for coating optical fibers and coatings produced therefrom ) 是由保卢斯·安东尼厄斯·玛丽亚·斯蒂曼阿德里亚努斯·科内利斯·巴斯蒂安·博格尔兹马克·佩佩尔斯于 2018-12-03 设计创作，主要内容包括：本文描述和要求保护的是用于涂覆光纤的辐射可固化组合物,具体地是初级涂料组合物,其中所述组合物具有规定的液态玻璃化转变温度和/或在介于例如25℃与85℃之间时的粘度比。此类组合物优选具有大量的具有非衍生自聚丙二醇的主链的反应性低聚物组分,优选地具有选定的二异氰酸酯成分的反应性低聚物；一种或多种反应性稀释剂单体；光引发剂；以及任选的一种或多种添加剂。此类组合物还优选地在室温下足够粘稠以确保最佳的光纤涂层可加工性。还描述了在其他地方描述的涂覆辐射可固化组合物的方法,以及由此产生的光纤涂层。(Described and claimed herein are radiation curable compositions, particularly primary coating compositions, for coating optical fibers, wherein the compositions have a defined liquid glass transition temperature and/or viscosity ratio between, for example, 25 ℃ and 85 ℃. Such compositions preferably have a substantial amount of a reactive oligomer component having a backbone not derived from polypropylene glycol, preferably a reactive oligomer having a selected diisocyanate component; one or more reactive diluent monomers; a photoinitiator; and optionally one or more additives. Such compositions are also preferably sufficiently viscous at room temperature to ensure optimal optical fiber coating processability. Methods of coating radiation curable compositions, as described elsewhere, and optical fiber coatings produced thereby are also described.)

1. A radiation curable composition for coating an optical fiber, comprising, relative to the total weight of the radiation curable composition as a whole:

At least 55 wt.% of a reactive oligomer comprising at least one polymerizable group and a backbone comprising a compound derived from polypropylene glycol;

a reactive diluent monomer;

a photoinitiator; and

optionally, one or more additives;

wherein the radiation curable composition has a liquid glass transition temperature (Tg, rheo), a first viscosity at 25 ℃ (. eta.)₂₅) A second viscosity (. eta.) at 55 deg.C₅₅) And a third viscosity (. eta.) at 85 deg.C₈₅)；

Wherein:

(1) the Tg, rheo of the radiation curable composition is less than-80 ℃, or from-120 ℃ to-81.5 ℃, or from-113 ℃ to-82 ℃, or from-113 ℃ to-85 ℃, or from-113 ℃ to-90 ℃, or from-120 ℃ to-97 ℃, or from-113 ℃ to-97 ℃, wherein the Tg, rheo is determined by fitting equation (8) to experimental viscosity versus temperature data for the radiation curable composition:

wherein η (T) is the viscosity (in Pa · s) of the composition at a temperature T (in ° c);

(2) Wherein the ratio of the first viscosity to the third viscosity is less than 13.9, or less than 13, or less than 12.1, or less than 11.5, or less than 10.7, or less than 8.9, and greater than 5.

2. A radiation curable composition for coating an optical fiber, the radiation curable composition comprising:

a reactive oligomer comprising at least one polymerizable group and a backbone comprising a compound derived from polypropylene glycol;

a reactive diluent monomer;

a photoinitiator; and

optionally, one or more additives;

Wherein:

(1) the Tg, rheo of the radiation curable composition is less than-80 ℃, or from-120 ℃ to-81.5 ℃, or from-113 ℃ to-82 ℃, or from-113 ℃ to-85 ℃, or from-113 ℃ to-90 ℃, or from-113 ℃ to-97 ℃, wherein the Tg, rheo is determined by fitting equation (8) to experimental viscosity versus temperature data for the radiation curable composition:

wherein η (T) is the viscosity (in Pa · s) of the composition at a temperature T (in ° c);

(2) Wherein the ratio of the first viscosity to the third viscosity is less than 13.9, or less than 13, or less than 12.1, or less than 11.5, or less than 10.7, or less than 8.9, and greater than 5; and is

Wherein the first viscosity of the radiation curable composition is greater than 5 Pascal seconds (Pa s), or is from 5Pa s to 20Pa s, or from 5Pa s to 12Pa s, or from 5Pa s to 10Pa s.

3. A radiation curable composition for coating an optical fiber, the radiation curable composition comprising:

a reactive oligomer comprising at least one polymerizable group and a backbone comprising a compound derived from polypropylene glycol;

a reactive diluent monomer;

a photoinitiator; and

optionally, one or more additives;

Wherein the Tg, rheo of the radiation curable composition is less than-100 ℃, or is from-120 ℃ to-100 ℃, or from-115 ℃ to-105 ℃, wherein Tg, rheo is determined by fitting equation (8) to experimental viscosity versus temperature data for the radiation curable composition:

where η (T) is the viscosity (in Pa · s) of the composition at the temperature T (in ° c).

4. A radiation curable composition for coating an optical fiber, the radiation curable composition comprising:

a reactive oligomer comprising at least one polymerizable group and a backbone comprising a compound derived from polypropylene glycol;

a reactive diluent monomer;

a photoinitiator; and

optionally, one or more additives;

wherein the reactive oligomer has a linear average molecular weight as measured by Size Exclusion Chromatography (SEC):

the peak molecular weight (Mp) of the polymer,

z average molecular weight (Mz), and

number average molecular weight (Mn);

wherein the reactive oligomer has a Relative High Molecular Weight Ratio (RHMWR) of-0.3 to 3, wherein

Wherein the radiation curable composition has a liquid glass transition temperature (Tg, rheo), a first viscosity at 25 ℃ (. eta.)₂₅) A second viscosity (. eta.) at 55 deg.C₅₅) And a third viscosity (. eta.) at 85 deg.C₈₅) (ii) a And is

Wherein:

(1) the Tg, rho of the radiation curable composition is less than-80 ℃, or from-120 ℃ to-81.5 ℃, or from-113 ℃ to-82 ℃, or from-113 ℃ to-85 ℃, or from-113 ℃ to-90 ℃, or from-113 ℃ to-97 ℃, wherein Tg, rho is determined by fitting experimental viscosity versus temperature data for the radiation curable composition to equation (8):

Wherein η (T) is the viscosity (in Pa · s) of the composition at a temperature T (in ° c);

(2) Wherein the ratio of the first viscosity to the third viscosity is less than 13.9, or less than 13, or less than 12.1, or less than 11.5, or less than 10.7, or less than 8.9, and greater than 5.

5. A radiation curable composition for coating an optical fiber, the radiation curable composition comprising:

a reactive oligomer comprising at least one polymerizable group and a backbone comprising a compound derived from polypropylene glycol;

a polar reactive diluent monomer;

a photoinitiator; and

optionally, one or more additives;

Wherein:

(1) the Tg, rho of the radiation curable composition is less than-80 ℃, or from-120 ℃ to-81.5 ℃, or from-113 ℃ to-82 ℃, or from-113 ℃ to-85 ℃, or from-113 ℃ to-90 ℃, or from-113 ℃ to-97 ℃, wherein Tg, rho is determined by fitting equation (8) to experimental viscosity versus temperature data for the radiation curable composition:

Wherein η (T) is the viscosity (in Pa · s) of the composition at a temperature T (in ° c);

(2) Wherein the ratio of the first viscosity to the third viscosity is less than 13.9, or less than 13, or less than 12.1, or less than 11.5, or less than 10.7, or less than 8.9, and greater than 5;

wherein the boltzmann average dipole moment, calculated by weight fraction, of the polar reactive diluent monomer is greater than 2.2 debye (D), or greater than 2.3D, or greater than 2.35D, or greater than 2.5D, or from 2.2D to 4.2D, or from 2.3D to 4.1D, or from 2.35D to 4.0D, or from 2.35D to 3.7D, or from 2.35D to 3.0D, or from 2.4D to 4.1D, or from 2.4D to 4.0D, or from 2.4D to 3.7D, or from 2.4D to 3.0D.

6. A radiation curable composition for coating an optical fiber, the radiation curable composition comprising:

a reactive oligomer comprising at least one polymerizable group;

a reactive diluent monomer;

a photoinitiator; and

optionally, one or more additives;

wherein the radiation curable composition has a liquid glass transition temperature (Tg, rheo), a first viscosity at 25 ℃ (. eta.)₂₅) A second viscosity (. eta.) at 55 deg.C ₅₅) And a third viscosity (. eta.) at 85 deg.C₈₅)；

Wherein:

(1) the Tg, rho of the radiation curable composition is less than-80 ℃, or from-120 ℃ to-81.5 ℃, or from-113 ℃ to-82 ℃, or from-113 ℃ to-85 ℃, or from-113 ℃ to-90 ℃, or from-113 ℃ to-97 ℃, wherein Tg, rho is determined by fitting equation (8) to experimental viscosity versus temperature data for the radiation curable composition:

wherein η (T) is the viscosity (in Pa · s) of the composition at a temperature T (in ° c);

(2) Wherein the ratio of the first viscosity to the third viscosity is less than 13.9, or less than 13, or less than 12.1, or less than 11.5, or less than 10.7, or less than 8.9, and greater than 5;

wherein the reactive oligomer comprises a urethane acrylate oligomer as a product of reactants comprising an isocyanate, a polyol, and an acrylate monomer;

wherein the polyol comprises polypropylene glycol;

and the isocyanate comprises isophorone diisocyanate, 2, 4-isomer toluene diisocyanate, 4, 4' -methylene dicyclohexyl diisocyanate, 1, 5-pentane diisocyanate, 2, 4-trimethyl-hexamethylene diisocyanate, 2, 4, 4-trimethyl-hexamethylene diisocyanate or hexamethylene diisocyanate, or a combination thereof.

7. The radiation curable composition according to any one of the preceding claims, wherein the reactive diluent monomer comprises 2-ethylhexyl acrylate, 2-phenoxyethyl acrylate, 2- (2-ethoxyethoxy) ethyl acrylate, N-vinylpyrrolidone, dimethylacrylamide, N-vinylcaprolactam, ethoxylated 2-phenoxyethyl acrylate, 4-hydroxybutyl acrylate, lauryl acrylate, isobornyl acrylate, caprolactone acrylate, ethoxylated nonylphenol acrylate or isodecyl acrylate, or a combination thereof.

8. The radiation curable composition according to any one of claims 1-4, wherein the reactive diluent monomer consists essentially of: 2-ethylhexyl acrylate, 2-phenoxyethyl acrylate, 2- (2-ethoxyethoxy) ethyl acrylate, N-vinylpyrrolidone, or dimethylacrylamide, or a combination thereof.

9. The radiation curable composition according to any one of the preceding claims, wherein the reactive oligomer comprises a block copolymer comprising at least one polyether block, wherein the reactive oligomer has a mono-, di-or tri-block structure,

Wherein the monoblock structure is defined as an average number of polyether blocks per unreacted oligomer of from 0.9 to less than 1.5,

the diblock structure is defined as the average number of polyether blocks per unreacted oligomer of from 1.5 to less than 2.5, and

the triblock structure is defined as having an average number of polyether blocks per unreacted oligomer of 2.5 to less than 3.5.

10. The radiation curable composition according to any one of the preceding claims, wherein the reactive oligomer is difunctional and has a weight average molecular weight of from 8,000 to 25,000 g/mol.

11. The radiation curable composition according to any one of the preceding claims, wherein the molar ratio of the compound derived from polypropylene glycol to isocyanate is from 1: 4 to 1: 1, or from 1: 2 to 3: 4.

12. The radiation curable composition according to any one of the preceding claims, wherein the radiation curable composition is a liquid at each of the first, second and third viscosities, and the ratio of the first viscosity to the third viscosity is from 6.4 to 13.9, or from 7.2 to 13, or from 7.2 to 12.1, or from 8.9 to 12.1, or from 10.7 to 12.1, or from 6.4 to 10.7, or from 6.4 to 8.9.

13. The radiation curable composition of any one of the preceding claims, wherein the ratio of the first viscosity to the second viscosity is from 2.9 to 4.98, from 2.9 to 4.6, from 3 to 4.6, or from 3 to 4.

14. The radiation curable composition according to any one of the preceding claims, wherein the third viscosity is greater than 0.10 Pa-s, or less than 1 Pa-s, or between 0.01 Pa-s and 2 Pa-s.

15. The radiation curable composition according to any one of the preceding claims comprising a second reactive diluent monomer, wherein the second reactive diluent comprises a diacrylate compound present at 0.25 wt% to 10 wt%, or 0.5 wt% to 5 wt%, or 1 wt% to 5 wt% relative to the total composition.

16. The radiation curable composition according to any one of the preceding claims, wherein a cured film formed from the radiation curable composition has a tensile modulus E'23 of less than 1.0MPa, more preferably less than 0.9MPa, more preferably less than 0.8MPa, even more preferably less than 0.7MPa, or less than 0.6MPa, or less than 0.5MPa, or from 0.3MPa to 0.9MPa, or from 0.3MPa to 0.85 MPa.

17. A radiation-curable composition, wherein a cured film formed from the radiation-curable composition has a strain energy release rate G₀Greater than 20J/m²Or more than 30J/m²Or more than 35J/m²Or more than 40J/m²Or more than 50J/m²Or from 25J/m²To 60J/m²Or from 30J/m²To 60J/m²Or from 34J/m²To 55J/m²。

18. A radiation curable composition wherein a cured film formed from the radiation curable composition has an Edward-Vilgis strain hardening parameter a of greater than 0.07, or greater than 0.09, or greater than 0.15, or from 0.07 to 0.30, or from 0.08 to 0.25, or from 0.10 to 0.20, or from 0.15 to 0.25, or from 0.15 to 0.20.

19. The radiation curable composition according to any one of the preceding claims, wherein the composition comprises, relative to the total weight of the composition:

from 60 wt% to 82 wt%, or from 65 wt% to 80 wt% of the reactive oligomer;

5 to 38 wt%, or 10 to 35 wt% of the reactive diluent monomer;

1 to 5 weight percent of the photoinitiator;

and 1 to 5 wt% of an additive.

20. A radiation curable composition for coating an optical fiber, comprising, relative to the total weight of the radiation curable composition as a whole:

At least 60% by weight of a reactive oligomer comprising at least one polymerizable group and a backbone comprising a compound derived from polypropylene glycol;

a polar reactive diluent monomer;

a photoinitiator; and

optionally, one or more additives;

wherein the reactive oligomer has a linear average molecular weight as measured by Size Exclusion Chromatography (SEC):

the peak molecular weight (Mp) of the polymer,

z average molecular weight (Mz), and

number average molecular weight (Mn);

wherein the reactive oligomer has a Relative High Molecular Weight Ratio (RHMWR) of-0.3 to 3, wherein

Wherein:

(1) wherein the Tg, rho of the radiation curable composition is less than-100 ℃, or is from-120 ℃ to-100 ℃, or from-115 ℃ to-105 ℃, or from-113 ℃ to-97 ℃, wherein Tg, rho is determined by fitting equation (8) to experimental viscosity versus temperature data for the radiation curable composition:

wherein η (T) is the viscosity (in Pa · s) of the composition at a temperature T (in ° c);

(2) Wherein the ratio of the first viscosity to the third viscosity is less than 13.9, or less than 13, or less than 12.1, or less than 11.5, or less than 10.7, or less than 8.9, and greater than 5;

wherein the first viscosity of the radiation curable composition is greater than 5 Pascal seconds (Pa s), or is from 5Pa s to 20Pa s, or from 5Pa s to 12Pa s, or from 5Pa s to 10Pa s, or from 5Pa s to 8Pa s; and is

Wherein the boltzmann average dipole moment, calculated by weight fraction, of all reactive diluent monomers in the radiation curable composition is greater than 2.2 debye.

Technical Field

The present invention generally relates to methods of coating optical fibers; radiation curable coatings suitable for use on optical fibers made using high speed, low helium, and/or high temperature drawing; and optical fibers produced therefrom.

Cross Reference to Related Applications

This application claims priority to U.S. provisional application No. 62/679383, filed on 1/6/2018, the entire contents of which are hereby incorporated by reference as if fully set forth herein.

Background

Optical fibers have been used in a variety of applications and have several advantages over other media. For example, data may be transmitted over optical fibers at higher data rates than over wires. Optical fibers are also lighter and more flexible than wires. Optical fibers, in particular those made of glass, are therefore often used in the telecommunications industry for data transmission. However, if left unprotected, optical fibers are not suitable for field use due to the fragility of the thin glass strand (glass strand) that carries the optical signal. In addition to being susceptible to physical damage, uncoated optical fibers can also be adversely affected by moisture exposure. Therefore, surface coatings have long been applied to optical fibers for protection and to ensure a high level of performance.

It is well known to draw glass fibres from specially prepared cylindrical preforms which have been locally and symmetrically heated to a temperature of, for example, about 2000 ℃. Glass fibers are drawn from the molten material as the preform is heated, such as by feeding the preform into and through a furnace. After the glass fibers have been drawn from the preform, the surface coating composition is applied to the glass fibers, preferably immediately after cooling. The coating composition is then cured to produce a coated optical fiber. The general method of applying a two-layer coating composition to moving glass fibers is well known in the art and is disclosed in U.S. Pat. No. 4474830 to Taylor and U.S. Pat. No. 3, 4851165 to Rennell et al. Newer fiber design concepts can be found in US 8837892, US 2014/0294355, and US 2015/0071595.

In order to protect the optical fiber, two or more superimposed radiation curable coatings are often applied to the optical fiber immediately after the optical fiber is produced by drawing. The coating in direct contact with the optical fiber is referred to as the "inner primary coating" and the cover coating is referred to as the "outer primary coating". In some references, the inner primary coating is also referred to simply as the "primary coating", while the outer primary coating is referred to as the "secondary coating". The inner primary coating is typically formulated to have a significantly lower modulus than the secondary coating.

The relatively soft inner primary coating provides resistance to microbending that results in increased signal transmission attenuation (i.e., signal loss) of the coated optical fiber and is therefore undesirable. Microbends are microscopic curvatures in optical fibers, involving local axial displacements of a few microns and spatial wavelengths of a few millimeters. Microbending may be induced by thermal stress and/or mechanical lateral forces. The coating may provide lateral force protection that protects the optical fiber from microbending, but as the coating thickness decreases, the amount of protection provided decreases. For example, in D.Gloge, "Optical-fiber packaging and its in flow on fiber strain and loss", Bell System Technical Journal, Vol.54, 2, 245 (1975); gardner, "labeling Loss in Optical Fibers," Bell System Technical Journal, Vol.54, No. 2, p.457 (1975); baldauf, "Relationship of Mechanical Characteristics of Dual Coated Single Mode Optical Fibers and Microbending Loss", IEICE Trans.Commun, Vol.E 76-B, No. 4, 352 (1993); and K.Kobayashi, "Study of micro-bending Loss in Thin Coated Fibers and Fiber Ribbons", IWCS, 386(1993), discusses the relationship between coatings and protection from lateral stresses that cause Microbending. The harder outer primary coating (i.e., the secondary coating) provides resistance to processing forces such as those encountered when the coated fibers are formed into ribbons and/or formed into cables.

Optical fiber secondary coating compositions typically comprise, prior to curing, a mixture of ethylenically unsaturated compounds, typically consisting of one or more oligomers and a photoinitiator dissolved or dispersed in a liquid ethylenically unsaturated diluent. The coating composition is typically applied to the optical fiber in liquid form and then exposed to actinic radiation to effect curing.

The primary coatings preferably have a higher refractive index than the cladding of the associated optical fiber in order to enable them to eliminate false optical signals from the core of the optical fiber. The primary coating should maintain sufficient adhesion to the glass fibers during heat aging and hydrolytic aging, but also be able to peel off from the glass fibers for splicing purposes, if desired. The primary coating typically has a thickness in the range of 20-50 μm (e.g., about 25 μm or 32.5 μm), with a thinner thickness in the range of 15-25 μm for 200 μm fibers.

The thickness of the primary coating is typically less than about 40 μm, although other thicknesses may be used. The primary coating is typically applied to the glass fibers and then cured. Various additives may also be present to enhance one or more characteristics of the primary coating, including antioxidants, adhesion promoters, inhibitors, photosensitizers, carrier surfactants, adhesion promoters, catalysts, stabilizers, surfactants, and optical brighteners.

The secondary coating is an outer coating. The secondary coating is, for example, the polymerization product of a coating composition whose molecules become highly crosslinked upon polymerization. The secondary coating typically has a high in-situ modulus (e.g., greater than about 800MPa, more preferably between about 1GPa and about 3GPa, at 25 ℃) and a high T_g(e.g., greater than about 50 deg.C). The in situ secondary modulus is preferably greater than about 1000 MPa. The secondary coating typically has a thickness of less than about 40 μm.

Optical fiber coatings (including primary and secondary layers) are typically applied using one of two methods: wet-on-wet (WOW) and wet-on-dry (WOD). In the WOD process, the fibers are first subjected to a primary coating application, which is then cured by exposure to Ultraviolet (UV) radiation. The fibers then undergo secondary coating application, which is then cured by a similar method. In the WOW process, the fibers are subjected to both primary and secondary coating applications, then the fibers proceed to a curing step. In the wet-on-wet process, the curing lamps between the application of the primary coating and the application of the secondary coating are eliminated.

Radiant light energy is used in the manufacture of radiation curable coatings for optical fibers. Specifically, the curing process uses radiant energy from an ultraviolet lamp to cure the optical fiber coating. Ultraviolet lamps having a broad mercury spectrum are widely used in industry because their high intensity and broad emission spectrum ensure rapid and complete curing of such radiation curable coatings. Increasingly, curing systems utilizing UV-LED (light emitting diode) lamps have also begun to be used because their efficient construction enables the fiber production process to have reduced energy input.

The global demand for optical fibers continues to grow comparably. To meet this growing demand and also to provide productivity advantages in such competitive industries, it would be beneficial, among other things, to increase the speed of optical fiber formation, coating and curing. Current coating and processing techniques have enabled most fiber producers to comfortably operate drawing towers at line speeds of at least 1000m/min, with speeds as high as 1500m/min and even 2500m/min and higher being possible.

However, as the fiber draw speed increases, several technical challenges are introduced into the process, thereby increasing the difficulty in producing a properly coated optical fiber. Among these technical challenges are the reduced ability of the ultraviolet light source to apply a sufficient dose of radiation to fully cure the primary and secondary coating compositions due to the reduced relative curing exposure time. Further challenges include an increased tendency for run out or concentricity errors in the application of the coated fibers, as vibrations characterized by higher line speeds can induce physical motion beyond the precise coating application tolerances. Still other challenges include bubble entrapment, coating delamination, and microbending-induced attenuation increase.

Many of these challenges are induced or exacerbated by undesirable temperature differences between the as-drawn glass fibers and the primary coating composition in contact therewith. At higher draw speeds, the fibers may enter the primary coating die at temperatures that may significantly exceed 50 ℃. All other things being equal, as the fiber draw speed increases, the previously melted glass fibers have less time to equilibrate to the ambient temperature at which the primary coating composition is applied. Insufficiently cooled glass fibers will induce a concomitant temperature increase in the primary coating during application, which may continue to the downstream curing step. This phenomenon will adversely affect coating compositions (especially primary coating compositions) with insufficient heat resistance, thus leading to a deterioration in the physical properties-even commercial viability-of the coated optical fibers produced therefrom.

Methods of attempting to alleviate this problem are well known in the industry. Such methods include increasing the rate at which freshly drawn glass fibers can be cooled by applying a fluid having a higher heat transfer coefficient than ambient air (e.g., nitrogen or helium). Helium is known to be effective because of its particularly high heat transfer coefficient. However, the amount of helium required to cool the glass fiber grows exponentially with increasing draw speed, such that there is a physical limit to the amount of helium that can be applied in the limited cooling tube space over a defined period of time. Furthermore, the high cost of helium makes it an expensive input during the fiber production process. The exponentially growing demand for such expensive variables will quickly offset the value of any productivity gains realized by the increased throughput achieved by higher line speeds. Therefore, additional solutions are needed.

Further attempts to alleviate these problems by process optimization, higher build drawing towers, more efficient helium application and fiber draw enhancement are known. However, in order to actually and more cost effectively enable the optical fiber coating process to be used at even higher speeds (e.g., 3000m/min or more), or at existing speeds and with reduced (or eliminated) amounts of expensive helium gas required, it is necessary to improve the performance of the radiation curable coating composition itself. In particular, there is an unmet need to provide optical fiber coatings, particularly primary coatings, that exhibit excellent processability at high temperatures. Such higher temperatures may be introduced via faster line processing speeds, reduced helium gas input, or both. Furthermore, there is an unmet need to provide optical fiber coatings that have both adequate thermal resistance while also being able to maintain or exceed the industry-desired levels of existing coating performance. In addition to being processable at higher line speeds or with lower helium input, such improved primary coatings may also need to cure quickly, exhibit adequate glass adhesion, and contribute to excellent microbending resistance by having a low modulus.

Disclosure of Invention

Several embodiments of the present invention are described herein. A first aspect is a coated optical fiber comprising an optical fiber portion that itself further comprises a glass core and a cladding in contact with and surrounding the glass core; and a coating portion further comprising a primary coating in contact with and surrounding the cladding; and a secondary coating in contact with and surrounding the primary coating. According to certain embodiments of this first aspect, the primary coating is the cured product of a radiation curable composition comprising a urethane acrylate oligomer as the product of reactants including an isocyanate, a polyol, and an acrylate monomer; a reactive diluent monomer; and a free radical photoinitiator; wherein the radiation curable composition has a first viscosity at 25 degrees Celsius (C.), a second viscosity at 55 ℃ and a third viscosity at 85 ℃, wherein the radiation curable composition is a liquid at each of the first, second and third viscosities, and wherein the ratio of the first viscosity to the third viscosity is less than about 15, or less than about 14.4, or less than about 13.9, or less than about 13, or less than about 12, or less than about 11, or less than about 10, or less than about 9, or less than about 7.

According to another embodiment of the first aspect, the coated optical fiber is a single mode or large effective area optical fiber, or any other optical fiber where coating process speed is important, including multimode optical fibers. In such other embodiments of the first aspect, the coated optical fiber may have a mode field diameter at a wavelength of 1310nm of 8 μm to 10 μm, or a mode field diameter at a wavelength of 1550nm of 9 μm to 13 μm, and/or an effective area of 20 μm²And 200 μm²In the meantime.

A second aspect is a radiation curable composition for coating an optical fiber, the radiation curable composition comprising: a reactive oligomer comprising at least one polymerizable group and a backbone derived from a diol comprising polypropylene glycol; a reactive diluent monomer; a photoinitiator; and one or more additives. The radiation curable composition of the second aspect further has a liquid glass transition temperature (Tg, rheo), a first viscosity at 25 degrees celsius (° c), a second viscosity at 55 ℃, and a third viscosity at 85 ℃; wherein at least one or two of the following conditions are satisfied:

(1) the radiation curable composition has a Tg, rheo of less than-81.5 ℃, or from-120 ℃ to-80 ℃, or from-115 ℃ to-80 ℃, or from-110 ℃ to-80 ℃, or from-100 ℃ to-80 ℃, or from-120 ℃ to-82 ℃, or from-115 ℃ to-82 ℃, or from-110 ℃ to-82 ℃, or from-100 ℃ to-82 ℃, or from-120 ℃ to-85 ℃, or from-115 ℃ to-85 ℃, or from-110 ℃ to-85 ℃, or from-100 ℃ to-85 ℃, or from-120 ℃ to-90 ℃, or from-115 ℃ to-90 ℃, or from-110 ℃ to-90 ℃, or from-100 ℃ to-90 ℃; or from-120 ℃ to-97 ℃, or from-113 ℃ to-97 ℃; or

(2) Wherein the ratio of the first viscosity to the third viscosity is less than about 15, or less than about 14.4, or less than about 13.9, or less than about 13, or less than 12, or less than about 11, or less than about 10, or less than about 9, or less than about 7.

According to another embodiment of the second aspect, the liquid glass transition temperature Tg, rheo of the composition is determined by fitting equation (8) to experimental viscosity versus temperature data for a radiation curable composition:

where η (T) is the viscosity of the composition (in pascal seconds) at temperature T (in degrees Celsius), and η₂₅Is the first viscosity.

Other embodiments of the second aspect of the invention provide for varying viscosity ratios of the composition, whether between the first viscosity and the second viscosity or between the first viscosity and the third viscosity. Still further embodiments of the second aspect provide for various steady state viscosity values (at a shear rate of 10/sec). Additional embodiments describe various chemical ingredients, ratios, amounts and types that may be incorporated into compositions according to the present invention.

A third aspect of the present invention is a coated optical fiber comprising a primary coating, wherein the primary coating is a cured product of the radiation curable composition according to any embodiment of the second aspect.

A fourth aspect of the present invention is a method for producing a coated optical fiber, the method comprising the steps of: drawing a glass optical fiber by a drawing tower; applying a primary coating composition onto a surface of the glass optical fiber; optionally, applying a dose of ultraviolet light sufficient to at least partially cure the primary coating composition; applying a secondary coating composition to the primary coating composition; exposing a primary coating composition and a secondary coating composition to at least one radiation source capable of emitting ultraviolet radiation to affect curing of the primary coating composition and the secondary coating composition to form a cured primary coating on a surface of the optical fiber, and a cured secondary coating on a surface of the cured primary coating; wherein the primary coating composition comprises: a reactive oligomer comprising at least one polymerizable group and a backbone derived from a diol comprising polypropylene glycol; a reactive diluent monomer; and one or more photoinitiators; wherein the radiation curable composition has a liquid glass transition temperature (Tg, rheo), a first viscosity at 25 degrees celsius (° c), a second viscosity at 55 ℃, and a third viscosity at 85 ℃; wherein the radiation curable composition has a Tg, rheo of less than-81.5 ℃, or from-120 ℃ to-80 ℃, or from-115 ℃ to-80 ℃, or from-110 ℃ to-80 ℃, or from-100 ℃ to-80 ℃, or from-120 ℃ to-82 ℃, or from-115 ℃ to-82 ℃, or from-110 ℃ to-82 ℃, or from-100 ℃ to-82 ℃, or from-120 ℃ to-90 ℃, or from-115 ℃ to-90 ℃, or from-110 ℃ to-90 ℃, or from-100 ℃ to-90 ℃, or from-120 ℃ to-97 ℃, or from-113 ℃ to-97 ℃; and/or wherein the ratio of the first viscosity to the third viscosity is less than about 15, or less than about 14.4, or less than about 13.9, or less than about 13, or less than about 9, or less than about 7.

Another embodiment of the fourth aspect describes an optical fiber coating process according to one or more of the following conditions: at a drawing speed of more than 1500m/min, or more than 1700m/min, or more than 2000m/min, or more than 2500m/min, or more than 3000m/min, and less than 5000m/min, or less than 4000m/min, or less than 3100 m/min; or in the absence of helium, or at a flow rate of less than 20 standard liters per minute (SLM), or less than 10SLM, or less than 5SLM, or 1SLM to 20SLM, or 1SLM to 10SLM, or 1SLM to 5SLM, or 5SLM to 20SLM, or 5SLM to 10 SLM.

A fifth aspect of the present invention is an optical fiber cable, wherein the optical fiber comprises at least one optical fiber according to the first or third aspect of the present invention, wherein the optical fiber is a cured product of the composition according to the second aspect of the present invention, and/or wherein the optical fiber is coated according to the fourth aspect of the present invention.

Drawings

FIG. 1 schematically depicts a cross-section of an optical fiber according to embodiments described herein;

FIG. 2 is a cross-sectional view taken along line AA-and showing the construction of one exemplary embodiment of the optical fiber of FIG. 1;

figure 3 shows a curve fit of an embodiment of the invention (example 14) performed to establish Tg, rheo values according to the procedure specified herein.

Fig. 4 shows the relative improved heat sensitivity of embodiments of the invention compared to comparative examples when the steady state viscosity of each composition is plotted as a function of temperature between 25 ℃ and 85 ℃.

Figure 5 also shows the relative improved heat sensitivity of embodiments of the invention (examples 14 and 19) compared to comparative examples (comparative examples 4 and 5) when the steady state viscosity of each composition is plotted as a function of temperature between 25 ℃ and 85 ℃.

Figure 6 depicts various compositions according to the present invention and various comparative examples, showing the steady state viscosity at 25 ℃ for each composition, and a plot of the viscosity ratio between 25 ℃ and 55 ℃ for each composition.

Figure 7 depicts various compositions according to the present invention and various comparative examples, showing the steady state viscosity at 85 ℃ for each composition, and a plot of the viscosity ratio between 25 ℃ and 85 ℃ for each composition.

Fig. 8 depicts various other compositions according to the present invention, showing the steady state viscosity at 85 ℃ for each composition, and a plot of the viscosity ratio between 25 ℃ and 85 ℃ for each composition.

FIG. 9 depicts for less than 1/λ with respect to example 53_min1/λ value of (a), least squares fit of Edward-Vilgis uniaxial Mooney curves to Mooney curves from experimental stress/strain data.

Detailed Description

A first embodiment of the present invention is a coated optical fiber comprising an optical fiber portion itself further comprising a glass core and a cladding in contact with and surrounding the glass core; and a coating portion further comprising a primary coating in contact with and surrounding the cladding; and a secondary coating in contact with and surrounding the primary coating. According to this first aspect, the primary coating is the cured product of a radiation curable composition comprising a urethane acrylate oligomer as the product of reactants including an isocyanate, a polyol, and an acrylate monomer; a reactive diluent monomer; and a free radical photoinitiator; wherein the radiation curable composition has a first viscosity at 25 degrees Celsius (C.), a second viscosity at 55 ℃ and a third viscosity at 85 ℃, wherein the radiation curable composition is a liquid at each of the first, second and third viscosities, and wherein the ratio of the first viscosity to the third viscosity is less than about 15, or less than about 14.4, or less than about 13.9, or less than about 13, or less than about 12, or less than about 11, or less than about 10, or less than about 9, or less than about 7.

Fig. 1 is a side view of a fiber 10 as discussed herein. Fig. 2 is a cross-sectional view of the fiber 10, an example of the results of the coated fibers described herein.

Optical fiber 10 includes a core 11, a cladding 12, a primary coating 13 contacting and surrounding an outer annular cladding region, and a secondary coating 14. The outer diameter of the core 11 is D₁And the outer diameter of the cladding 12 is D₂. The primary coating 13 is typically a primaryA coating, said primary coating having an in situ (or on-fiber) tensile modulus of less than 1.5MPa, or less than 1.2MPa, or as low as 0.35MPa, 0.3MPa, or 0.25MPa, and in other embodiments not more than 0.2 MPa. Methods for describing in situ modulus are well known in the art and are described, inter alia, in US 7,171,103 and US 6,961,508, both assigned to DSM IP assests b.v. The cured primary coating 13 has an in situ glass transition temperature of less than-35 deg.C, or less than-40 deg.C, or less than-45 deg.C, and in other embodiments no greater than-50 deg.C. The primary coating with a low in situ modulus reduces microbending, which is a coupling mechanism between modes propagating in the fiber. The low in-situ glass transition temperature ensures that the in-situ modulus of the primary coating will remain low even when the fiber is deployed in very cold environments. Therefore, the microbend behavior will be stable with temperature, resulting in low mode coupling in all cases. The secondary coating 14 contacts and surrounds the primary coating 13. The secondary coating 14 has an in situ tensile modulus greater than 800MPa, or greater than 1110MPa, or greater than 1300MPa, or greater than 1400MPa, or greater than 1500 MPa. The secondary coating with a high in-situ modulus reduces microbending, which is a coupling mechanism between modes propagating in the fiber.

In the embodiments shown and described herein, the core 11 comprises pure silica glass (SiO)₂) Or silica glass with one or more dopants that increase the refractive index of the glass core relative to pure undoped silica glass. Suitable dopants for increasing the refractive index of the core include, but are not limited to, GeO₂、Al₂O₃、P₂O₅、TiO₂、ZrO₂、Nb₂O₅、Ta₂O₅And/or combinations thereof. Cladding layer 12 may comprise pure silica glass (SiO)₂) (ii) a Having one or more dopants that increase the refractive index (e.g., GeO)₂、Al₂O₃、P₂O₅、TiO₂、ZrO₂、Nb₂O₅And/or Ta₂O₅) Silica glasses, e.g. when the cladding is "Up-doped (up-doped) "; or silica glass with a refractive index-lowering dopant (e.g., fluorine), for example when the inner cladding is "down-doped", provided that the maximum relative refractive index [ delta ] of the core 11 is_1MAX]Greater than the maximum relative refractive index [ Delta ] of the cladding 12_4MAX]And (4) finishing. According to one embodiment, the cladding 12 is pure silica glass.

Any fiber type may be used in embodiments of the present invention. However, in a preferred embodiment, the coated optical fiber has a mode field diameter of 8 μm to 10 μm at a wavelength of 1310nm, or a mode field diameter of 9 μm to 13 μm at a wavelength of 1550nm, and/or an effective area of between 20 μm ²And 200 μm²In the meantime. Such fibers may be single mode and/or large effective area fibers in view of the anticipated demand for coating processes for these fibers that utilize higher line or process speeds. However, other fiber types, such as multimode fibers, may also be used.

The primary coating 13 preferably has a higher refractive index than the cladding 12 of the optical fiber 10 so that it can eliminate false optical signals from the fiber core. For example, the refractive index values of the core and cladding of the exemplary transmission fiber 10 at a wavelength of 1550nm are 1.447 and 1.436, respectively; therefore, the refractive index of the primary coating 13 at 1550nm is expected to be greater than 1.44. The primary coating 13 maintains sufficient adhesion to the glass fibers during heat aging and hydrolytic aging, but can also be peeled off of the glass fibers for splicing purposes (if desired). The primary coating 13 typically has a thickness in the range of 20-50 μm (e.g., about 25 μm or 32.5 μm), and for 200 μm fibers, a thinner thickness in the range of 15-25 μm.

The coating 13 is a primary coating that is typically applied directly to the glass fibers. The coating 13 preferably consists of a material having a low in-situ modulus and a low in-situ T_gIs formed from the soft cross-linked polymeric material of (a).

The thickness of the primary coating 13 is preferably less than about 40 μm, more preferably between about 20 μm and about 40 μm, and most preferably between about 20 μm and about 30 μm. The primary coating 13 is typically applied to the glass fibers and then cured, as will be described in more detail below. Various additives may also be present to enhance one or more characteristics of the primary coating, including antioxidants, adhesion promoters, PAG compounds, photosensitizers, carrier surfactants, adhesion promoters, catalysts, stabilizers, surfactants, and optical brighteners of the types described above.

In one embodiment, a suitable primary coating composition may include, but is not limited to, from about 10 weight percent to 95 weight percent, or from 10 weight percent to 90 weight percent, or from about 25 weight percent to about 75 weight percent of one or more urethane acrylate oligomers; from about 10 weight percent to about 65 weight percent, more preferably from about 25 weight percent to about 65 weight percent, of one or more monofunctional ethylenically unsaturated monomers; about 0 to about 10 weight percent of one or more multifunctional ethylenically unsaturated monomers; about 1 to about 5 weight percent of one or more photoinitiators; about 0.5pph to about 1.5pph of one or more antioxidants; optionally from about 0.5pph to about 1.5pph of one or more adhesion promoters; optionally about 0.1pph to about 10pph of a PAG compound; and from about 0.01pph to about 0.5pph of one or more stabilizers.

Coating 14 is an exterior coating and it serves the conventional purpose of a "secondary coating". The outer coating material 14 is, for example, a polymerization product of a coating composition whose molecules become highly crosslinked upon polymerization. In the embodiments described herein, the coating 14 has a high in-situ modulus (e.g., greater than about 800MPa at 25 ℃) and a high T_g(e.g., greater than about 50 deg.C). The in situ secondary modulus is preferably greater than about 1000MPa, more preferably greater than about 1100MPa, and most preferably greater than about 1200 MPa. According to some preferred embodiments, the in situ secondary modulus is greater than 1200 MPa. In other preferred embodiments, the in situ secondary modulus is between about 1000MPa and about 8000MPa, more preferably between about 1200MPa and about 5000MPa, and most preferably between about 1500MPa and about 3000 MPa. In situ T of the Secondary coating_gPreferably between about 50 ℃ and about 120 ℃, more preferably between about 50 ℃ and about 100 ℃. In one embodiment, the thickness of the secondary coating 14 is less than about 40 μm, more preferablyBetween about 20 μm to about 40 μm, most preferably between about 20 μm to about 30 μm.

Other suitable materials for the outer (or secondary) coating material, as well as considerations related to the selection of such materials, are well known in the art and are described, for example, in U.S. Pat. nos. 4,962,992 and 5,104,433, all to Chapin. As an alternative to these approaches, high modulus coatings have also been obtained using coating systems with lower oligomer content, as described in U.S. patent No. 6,775,451 to Botelho et al and U.S. patent No. 6,689,463 to Chou et al. In addition, non-reactive oligomer components have been used to achieve high modulus coatings, as described in U.S. patent application publication No. 20070100039 to Schissel et al. The outer coating is typically applied to the previously coated fibers (with or without prior curing) and then cured, as will be described in more detail below. Various additives may also be present to enhance one or more properties of the coating, including antioxidants, PAG compounds, photosensitizers, catalysts, lubricants, low molecular weight non-crosslinked resins, stabilizers, surfactants, slip additives, waxes, micronized polytetrafluoroethylene, and the like. The secondary coating may also comprise an ink, as is well known in the art.

Suitable compositions for the secondary or outer coating 14 include, but are not limited to, about 0 to 70 weight percent of one or more urethane acrylate oligomers; about 20 to about 95 weight percent of one or more multifunctional ethylenically unsaturated monomers; about 0 to about 10 weight percent of one or more monofunctional ethylenically unsaturated monomers; about 1 to about 5 weight percent of one or more photoinitiators; from about 0pph to about 5pph of one or more slip additives; and about 0.5pph to about 1.5pph of one or more antioxidants.

It is known in the art how to formulate typical optical fiber coatings for primary and secondary coatings of optical fibers as described above, as well as inks and matrix materials for curing using broadband ultraviolet lamps. Published by Elsevier, a. mendez andthe textbook "Specialty Optical Fibers Handbook" by morse,a thorough discussion of this technique and the related chemistry and testing methods can be found in section 4.6 at the end of chapter 4 in Elsevier inc.2007.

(1) The radiation curable composition has a Tg, rheo of less than-81.5 ℃, or from-120 ℃ to-80 ℃, or from-115 ℃ to-80 ℃, or from-110 ℃ to-80 ℃, or from-100 ℃ to-80 ℃, or from-120 ℃ to-82 ℃, or from-115 ℃ to-82 ℃, or from-110 ℃ to-82 ℃, or from-100 ℃ to-82 ℃, or from-120 ℃ to-90 ℃, or from-115 ℃ to-90 ℃, or from-110 ℃ to-90 ℃, or from-100 ℃ to-90 ℃, or from-120 ℃ to-97 ℃, or from-113 ℃ to-97 ℃; or

The radiation curable primary composition for coating an optical fiber according to the second aspect of the present invention contains at least two ethylenically unsaturated polymerizable compounds including at least one reactive diluent monomer and a radiation curable oligomer, and one or more photoinitiators, and optionally an additive package. Such components, as described below, may be used in radiation curable compositions according to any of the aspects of the invention, including coatings used in optical fibers according to the first aspect, compositions of the second aspect, and the like.

Ethylenically unsaturated polymerizable compounds

The ethylenically unsaturated polymerizable compound may contain one or more than one reactive olefinic double bond. They may be low molecular weight (monomeric) or high molecular weight (oligomeric) compounds.

Reactive diluent monomers

Typical examples of low molecular weight monomers containing one double bond are alkyl or hydroxyalkyl acrylates or methacrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-phenoxyethyl acrylate, 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate, isobornyl acrylate, methyl methacrylate and ethyl methacrylate, lauryl acrylate, ethoxylated nonylphenol acrylate and diethylene glycol ethylhexyl acrylate (DEGEHA). Other examples of such monomers are acrylonitrile, acrylamide, methacrylamide, N-substituted (meth) acrylamides, vinyl esters (e.g., vinyl acetate), styrene, alkylstyrenes, halostyrenes, N-vinyl pyrrolidone, N-vinyl caprolactam, vinyl chloride, and vinylidene chloride. Examples of monomers containing more than one double bond are ethylene glycol diacrylate, propylene glycol diacrylate, tripropylene glycol diacrylate, neopentyl glycol diacrylate, hexamethylene glycol diacrylate, bisphenol A diacrylate, 4' -bis (2-acryloyloxyethoxy) diphenylpropane, trimethylolpropane triacrylate, pentaerythritol triacrylate and pentaerythritol tetraacrylate, vinyl acrylate, divinylbenzene, divinyl succinate, diallyl phthalate, triallyl phosphate, triallyl isocyanurate or tris (2-acryloylethyl) isocyanurate.

The monomers used may be non-polar or polar. Some non-polar monomers that may be suitably used include 2-ethylhexyl acrylate (EHA), isodecyl acrylate (IDA), Lauryl Acrylate (LA), isobornyl acrylate (IBOA), and various caproic acidsLactone acrylates, e.g. commercially known as Tone^TMM100 or Sartomer SR 495B.

Particularly preferred are polar monomers including dimethylacrylamide (dMAA), N-vinylpyrrolidone (nVP), 2- (2-ethoxyethoxy) ethyl acrylate (EOEOEOA), 4-hydroxybutyl acrylate (4-HBA), 2-phenoxyethyl acrylate (PEA), and ethoxylated 2-phenoxyethyl acrylate (EPEA). The inventors have surprisingly found that more polar monomers having similar viscosities tend to contribute more effectively to the lower liquid glass transition temperature of their associated compositions relative to non-polar monomers. As discussed elsewhere herein below, such a combination of features can be valuable in facilitating the formulation of radiation curable compositions that exhibit certain advantages of the present invention.

Polarity is a relative concept that can be characterized and/or quantified in a variety of ways. One known method for determining the polarity of a monomer is to determine its calculated Boltzmann (Boltzmann) average dipole moment ("dipole moment"). A comprehensive list of calculated boltzmann average dipole moments of several radiation curable Monomers and methods for their determination is presented in Fast Monomers: fans influencing the incoming response of Acrylate Monomers in photosynthetic Acrylate Polymerization; macromolecules 2003, 36, 3681 and 3873 (revised 4/3/2003). Methods of determining such dipole moment values are also described in U.S. patent No. 6916855B 2, which is hereby incorporated by reference in its entirety. As used herein, a monomer is considered "polar" if its calculated boltzmann average dipole moment is 2.2 debye or greater. Thus, in one embodiment, the composition comprises or consists essentially of a reactive diluent monomer having a calculated boltzmann average dipole moment by weight greater than 2.2 debye (D), or greater than 2.3D, or greater than 2.35D, or greater than 2.5D, or from 2.2D to 4.2D, or from 2.3D to 4.1D, or from 2.35D to 4.0D, or from 2.35D to 3.7D, or from 2.35D to 3.0D, or from 2.4D to 4.1D, or from 2.4D to 4.0D, or from 2.4D to 3.7D, or from 2.4D to 3.0D. In an alternative embodiment, more than one reactive diluent monomer is used, and the combined boltzmann average dipole moment by weight of all reactive diluent monomers present in the composition is greater than 2.2 debye (D), or greater than 2.3D, or greater than 2.35D, or greater than 2.5D, or from 2.2D to 4.2D, or from 2.3D to 4.1D, or from 2.35D to 4.0D, or from 2.35D to 3.7D, or from 2.35D to 3.0D, or from 2.4D to 4.1D, or from 2.4D to 4.0D, or from 2.4D to 3.7D, or from 2.4D to 3.0D.

One or more of the above-described reactive diluent monomers may be used in the composition according to the present invention in any suitable amount, and may be selected individually or in combination with one or more of the types listed herein. In a preferred embodiment, the reactive diluent monomer component is present in an amount of from about 5 wt% to about 90 wt%, or from about 10 wt% to about 80 wt%, or from about 10 wt% to about 60 wt%, relative to the total weight of the composition.

Oligomer

Typically, the optical fiber coating material comprises a reactive oligomer component. Oligomers are molecules of intermediate relative molecular mass whose structure comprises a plurality of units derived, actually or conceptually, from molecules of lower relative molecular weight. As used herein, an "oligomer" has a number average molecular weight (Mn) of about 600g/mol to about 25,000g/mol as measured by Size Exclusion Chromatography (SEC) calibrated with polystyrene standards in tetrahydrofuran.

Such components typically include urethane acrylate oligomers comprising acrylate groups, urethane groups, and a backbone. The backbone is derived from a polyol and a hydroxyalkyl acrylate that have been reacted with an isocyanate (such as a diisocyanate, polyisocyanate).

Examples of suitable polyols are polyether polyols, polyester polyols, polycarbonate polyols, polycaprolactone polyols, acrylic polyols and other polyols. These polyols may be used alone or in a combination of two or more. In a preferred embodiment, the backbone of the urethane acrylate oligomer comprises a compound derived from polypropylene glycol (PPG). As used herein, a compound derived from polypropylene glycol includes capped PPG, e.g., EO-capped PPG. The polymerization mode of the structural units in these polyols is not particularly limited. Each of random polymerization, block polymerization, or graft polymerization is acceptable.

As used herein, a block copolymer refers to an oligomer or a portion of a polymer comprising a plurality of structural units, wherein at least one structural unit comprises a feature that is not present in an adjacent portion. As used herein, mono-, di-, and tri-block copolymers refer to the average amount of a particular block present in an oligomer. In a preferred embodiment, the specified blocks refer to polyether blocks derived from one or more of the polyols, preferably polyether polyols, as described elsewhere herein. In one embodiment, the blocks referred to as mono-, di-, and/or tri-block copolymers are polyether blocks derived from one or more of the polyols described elsewhere herein. In one embodiment, a mono-block copolymer may be described as a copolymer having only an average of about 1, or about 0.9 to less than 1.5 units of a particular block (e.g., a polyether block). In one embodiment, diblock copolymers may be described as copolymers having a specific block (e.g., polyether block) averaging about 2, or at least 1.5 to less than 2.5 units. In one embodiment, triblock copolymers can be described as copolymers having an average of about 3, or at least 2.5 to less than 3.5 units of a particular block (e.g., polyether block). The number of polyether units in a given oligomer may be determined by the number of polyether polyol molecules utilized in the synthesis of the individual oligomer.

Given as examples of polyether polyols are polyethylene glycol, polypropylene glycol-ethylene glycol copolymer, polytetramethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, polydecamethylene glycol, and polyether glycols obtained by ring-opening copolymerization of two or more ionic polymerizable cyclic compounds. Here, given as examples of the ionic polymerizable cyclic compound are cyclic ethers such as ethylene oxide, isobutylene oxide, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, dioxane, trioxane, tetraoxane, cyclohexene oxide, styrene oxide, epichlorohydrin, isoprene monooxide, vinyloxetane, vinyltetrahydrofuran, vinylcyclohexene oxide, phenyl glycidyl ether, butyl glycidyl ether, and glycidyl benzoate. Specific examples of combinations of two or more ionically polymerizable cyclic compounds include combinations for producing binary copolymers, such as tetrahydrofuran and 2-methyltetrahydrofuran, tetrahydrofuran and 3-methyltetrahydrofuran, and tetrahydrofuran and ethylene oxide; and combinations for producing terpolymers, such as tetrahydrofuran, 2-methyltetrahydrofuran, and ethylene oxide, tetrahydrofuran, 1-butylene oxide (1-oxide), and ethylene oxide, and the like. The ring-opening copolymer of these ionic polymerizable cyclic compounds may be a random copolymer or a block copolymer.

Included among these polyether polyols are products commercially available under the following trademarks, for example: PTMG1000, PTMG2000 (manufactured by Mitsubishi Chemical corp., ltd.), PEG #1000 (manufactured by Nippon Oil and falls co., ltd.), PTG650(SN), PTG1000(SN), PTG2000(SN), PTG3000, PTGL1000, PTGL2000 (manufactured by Hodogaya Chemical co., ltd.), PEG400, PEG600, PEG1000, PEG1500, PEG2000, PEG4000, PEG6000 (manufactured by Daiichi Kogyo Seiyaku co., ltd.), and Pluronics (manufactured by BASF).

Polyester diols obtained by reacting a polyol with a polybasic acid are given as examples of the polyol. As examples of the polyhydric alcohol, ethylene glycol, polyethylene glycol, tetramethylene glycol, polytetramethylene glycol, 1, 6-hexanediol, 3-methyl-1, 5-pentanediol, 1, 9-nonanediol, 2-methyl-1, 8-octanediol, and the like can be given. As examples of the polybasic acid, phthalic acid, dimer acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, adipic acid, sebacic acid, and the like can be given.

These polyester polyol compounds are commercially available under such trademarks as: MPD/IPA500, MPD/IPA1000, MPD/IPA2000, MPD/TPA500, MPD/TPA1000, MPD/TPA2000, Kurapol A-1010, A-2010, PNA-2000, PNOA-1010, and PNOA-2010 (manufactured by Kuraray Co., Ltd.).

As examples of the polycarbonate polyol, polycarbonate of polytetrahydrofuran, poly (hexanediol carbonate), poly (nonanediol carbonate), poly (3-methyl-1, 5-pentamethylene carbonate), and the like can be given.

As commercially available products of these polycarbonate polyols, DN-980, DN-981 (manufactured by Nippon Polyurethane Industry Co., Ltd.), Priplast 3196, 3190, 2033 (manufactured by Unichema), PNOC-2000, PNOC-1000 (manufactured by Kuraray Co., Ltd.), PLACCEL CD220, CD210, CD208, CD205 (manufactured by Daicel Chemical Industries, Ltd.), PC-THF-CD (manufactured by BASF), and the like can be given.

The polycaprolactone diol obtained by reacting epsilon-caprolactone with a diol compound is given as an example of a polycaprolactone polyol having a melting point of 0 deg.C or higher. Here, ethylene glycol, polyethylene glycol, polypropylene glycol, tetramethylene glycol, polytetramethylene glycol, 1, 2-polytetramethylene glycol, 1, 6-hexanediol, neopentyl glycol, 1, 4-cyclohexanedimethanol, 1, 4-butanediol, and the like are given as examples of the diol compound.

Commercially available products of these polycaprolactone polyols include PLACCEL 240, 230ST, 220ST, 220NP1, 212, 210, 220N, 210N, L230AL, L220AL, L220PL, L220PM, L212AL (both manufactured by Daicel Chemical Industries, Ltd.), Rauccarb 107 (manufactured by Enichem), and the like.

As examples of the other polyhydric alcohol, ethylene glycol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, polyoxyethylene bisphenol A ether, polyoxypropylene bisphenol A ether, polyoxyethylene bisphenol F ether, polyoxypropylene bisphenol F ether, and the like can be given.

As these other polyols, those having an alkylene oxide structure in the molecule, particularly polyether polyols, are preferable. In one embodiment, polyols containing polytetramethylene glycol and copolymer glycols of butylene oxide and ethylene oxide are particularly preferred.

The number average molecular weight, as derived from the hydroxyl number of these polyols, is generally from about 50 to about 15,000, and preferably from about 1,000 to about 8,000. As used herein, unless otherwise specified, molecular weight refers to the number average molecular weight specified in units of grams per mole (g/mol), as determined by SEC calibrated using polystyrene standards.

Given as examples of the polyisocyanate for the oligomer are 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 1, 3-xylylene diisocyanate, 1, 4-xylylene diisocyanate, 1, 5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3 '-dimethyl-4, 4' -diphenylmethane diisocyanate, 3 '-dimethylphenylene diisocyanate, 4' -biphenylene diisocyanate, 1, 6-hexane diisocyanate, isophorone diisocyanate, methylenebis (4-cyclohexyl isocyanate), 2, 4-trimethylhexamethylene diisocyanate, 2, 6-tolylene diisocyanate, 1, 3-xylylene diisocyanate, p-phenylene diisocyanate, 2, 4, 4-trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, bis (2-isocyanatoethyl) fumarate, 6-isopropyl-1, 3-phenyl diisocyanate, 4-diphenylpropane diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, tetramethylxylylene diisocyanate, lysine isocyanate and the like. These polyisocyanate compounds may be used alone or in combination of two or more. Preferred polyisocyanates are isophorone diisocyanate, 2, 4-trimethylhexamethylene diisocyanate, 2, 4, 4-trimethylhexamethylene diisocyanate and hexamethylene diisocyanate, 2, 4-toluene diisocyanate and 2, 6-toluene diisocyanate.

Examples of the hydroxyl group-containing (meth) acrylate used in the oligomer include (meth) acrylates derived from (meth) acrylic acid and epoxy, and (meth) acrylates containing alkylene oxide, more specifically 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl acrylate, 2-hydroxy-3-oxyphenyl (meth) acrylate, and hydroxyethyl caprolactone acrylate. Acrylate functionality is preferred over methacrylate.

The ratio of the polyol, the polyisocyanate and the hydroxyl group-containing (meth) acrylate used for preparing the urethane (meth) acrylate is determined such that about 1.1 to about 3 equivalents of the isocyanate group contained in the polyisocyanate and about 0.1 to about 1.5 equivalents of the hydroxyl group contained in the hydroxyl group-containing (meth) acrylate are used with respect to 1 equivalent of the hydroxyl group contained in the polyol.

In the reaction of these three components, a carbamation catalyst such as copper naphthenate, cobalt naphthenate, zinc naphthenate, di-n-butyltin dilaurate, triethylamine, and triethylenediamine-2-methyltriethyleneamine is often used in amounts of about 0.01 to about 1 weight percent of the total reactants. The reaction is carried out at a temperature of from about 10 ℃ to about 90 ℃, preferably from about 30 ℃ to about 80 ℃.

The number average molecular weight (Mn) of the polyurethane (meth) acrylates used in the compositions of the present invention is preferably in the range of from about 600 to about 25,000, more preferably from about 2,200 to about 10,000, as measured by Size Exclusion Chromatography (SEC) calibrated with polystyrene standards in tetrahydrofuran. If the Mn of the urethane (meth) acrylate is less than about 100, the resin composition tends to be cured; on the other hand, if Mn becomes greater than about 25,000, the viscosity of the composition becomes high, making handling of the composition difficult. In one embodiment, the inner primary coating oligomer has an Mn of between about 2,200 and about 5,500.

Other oligomers that may be used include polyester (meth) acrylates, epoxy (meth) acrylates, polyamide (meth) acrylates, siloxane polymers having (meth) acryloxy groups, reactive polymers obtained by reacting copolymers of (meth) acrylic acid and glycidyl methacrylate and other polymerizable monomers, and the like. Particularly preferred are acrylate oligomers based on bisphenol a, such as alkoxylated bisphenol-a-diacrylate and diglycidyl-bisphenol-a-diacrylate.

In addition to the above components, other curable oligomers or polymers may be added to the liquid curable resin composition of the present invention to such an extent that the properties of the liquid curable resin composition are not adversely affected.

Preferred oligomers are polyether-based acrylate oligomers, polycarbonate acrylate oligomers, polyester acrylate oligomers, alkyd acrylate oligomers and acrylated acrylic oligomers. More preferred are urethane-containing oligomers thereof. Even more preferred are polyether urethane acrylate oligomers and urethane acrylate oligomers using blends of the above polyols, and particularly preferred are aliphatic polyether urethane acrylate oligomers. The term "aliphatic" refers to the full aliphatic polyisocyanates used.

However, urethane-free acrylate oligomers, such as urethane-free acrylated acrylic oligomers, urethane-free polyester acrylate oligomers, and urethane-free alkyd acrylate oligomers are also preferred. Examples of such high molecular weight (oligomeric) polyunsaturated compounds are acrylated epoxy resins, acrylated polyethers and acrylated polyesters. Other examples of unsaturated oligomers are unsaturated polyester resins, which are typically prepared from maleic acid, phthalic acid and one or more diols and have molecular weights greater than about 500. Unsaturated oligomers of this type are also referred to as prepolymers. Typical examples of unsaturated compounds are esters of ethylenically unsaturated carboxylic acids with polyols or polyepoxides, and polymers containing ethylenically unsaturated groups in the chain or in side groups, including unsaturated polyesters, polyamides and copolymers thereof, polybutadiene and butadiene copolymers, polyisoprene and isoprene copolymers, polymers and copolymers containing (meth) acrylic groups in side chains, and mixtures of one or more such polymers. Illustrative examples of unsaturated carboxylic acids are acrylic acid, methacrylic acid, crotonic acid, itaconic acid, cinnamic acid, unsaturated fatty acids (e.g. linolenic acid or oleic acid). Suitable polyols are aromatic, aliphatic and cycloaliphatic polyols. The aromatic polyols are typically hydroquinone, 4' -dihydroxydiphenyl, 2-bis (4-hydroxyphenyl) propane, and also novolaks and cresols. Polyepoxides include those based on the polyols, for example, aromatic polyols and epichlorohydrin.

The reactive oligomer, which is an ethylenically unsaturated polymerizable oligomer, preferably comprises, consists of, or consists essentially of a urethane acrylate oligomer. The reactive oligomer has at least one polymerizable group, but in a preferred embodiment, the reactive oligomer is difunctional; that is, each molecule has an average of between 1.5 and 2.5 reactive groups.

One or more of the above ethylenically unsaturated oligomers may be used in the composition according to the invention in any suitable amount and may be selected individually or in combination with one or more of the types listed herein. In one embodiment, the ethylenically unsaturated oligomer component is present in an amount of about 5% to about 90%, or about 10% to about 80% by weight relative to the total weight of the composition. However, in a preferred embodiment, for a given high temperature resistant configuration, a significant amount of ethylenically unsaturated oligomer should be employed to achieve a desired first viscosity of the composition, for example at least 50 wt.%, or at least 55 wt.%, or at least 60 wt.%, or at least 65 wt.%, or at least 70 wt.%, or 45-85 wt.%, or 55 wt.% to 80 wt.%, or 60 wt.% to 85 wt.%, or 60 wt.% to 80 wt.%, relative to the total weight of the composition.

Free radical photoinitiator component

In a preferred embodiment, the liquid radiation curable resin for coating optical fibers of the present invention comprises a free radical photoinitiator component. The photoinitiator is a compound that chemically changes to generate at least one of a radical, an acid, and a base due to the action of light or a synergistic action between the action of light and the electronic excitation of the sensitizing dye.

According to one embodiment of the invention, the free radical photoinitiator is an acylphosphine oxide photoinitiator. Acylphosphine oxide photoinitiators are disclosed, for example, in U.S. patent nos. 4324744, 4737593, 5942290, 5534559, 6020529, 6486228, and 6486226.

The acylphosphine oxide photoinitiator is a bisacylphosphine oxide (BAPO) or a monoacylphosphine oxide (MAPO).

The bisacylphosphine oxide photoinitiator has the formula I:

wherein R is₅₀Is unsubstituted or substituted by 1 to 4 halogen or C₁-C₈Alkyl substituted C₁-C₁₂Alkyl, cyclohexyl or phenyl;

R₅₁and R₅₂Each independently of the other being C₁-C₈Alkyl or C₁-C₈An alkoxy group;

R₅₃is hydrogen or C₁-C₈An alkyl group; and is

R₅₄Is hydrogen or methyl.

For example, R₅₀Is unsubstituted or substituted by 1 to 4C₁-C₄C substituted by alkyl, Cl or Br₂-C₁₀Alkyl, cyclohexyl or phenyl. Another embodiment is where R is₅₀Is unsubstituted or substituted in position 2, 3, 4 or 2, 5 by C ₁-C₄Alkyl substituted C₃-C₈Alkyl, cyclohexyl or phenyl. For example, R₅₀Is C₄-C₁₂Alkyl or cyclohexyl radical, R₅₁And R₅₂Each independently of the other C₁-C₈Alkyl or C₁-C₈Alkoxy, and R₅₃Is hydrogen or C₁-C₈An alkyl group. For example, R₅₁And R₅₂Is C₁-C₄Alkyl or C₁-C₄Alkoxy, and R₅₃Is hydrogen or C₁-C₄An alkyl group. Another embodiment is where R is₅₁And R₅₂Is methyl or methylOxy and R₅₃Embodiments are hydrogen or methyl. For example, R₅₁、R₅₂And R₅₃Is methyl. Another embodiment is where R is₅₁、R₅₂And R₅₃Is methyl and R₅₄An embodiment of hydrogen. Another embodiment is where R is₅₀Is C₃-C₈Embodiments of alkyl groups. For example, R₅₁And R₅₂Is methoxy, R₅₃And R₅₄Is hydrogen, and R₅₀Is isooctyl. For example, R₅₀Is an isobutyl group. For example, R₅₀Is phenyl. The bisacylphosphine oxide photoinitiator of the present invention is, for example, bis (2, 4, 6-trimethylbenzoyl) -phenylphosphine oxide (CAS No. 162881-26-7) or bis (2, 4, 6-trimethylbenzoyl) - (2, 4-bis-pentyloxyphenyl) phosphine oxide.

The monoacylphosphine oxide photoinitiator has the formula II:

wherein

R₁And R₂Independently of one another are C₁-C₁₂Alkyl, benzyl, unsubstituted or substituted by halogen, C₁-C₈Alkyl and/or C₁-C₈Phenyl substituted 1 to 4 times by alkoxy, or cyclohexyl or a radical-COR ₃Or is or

R₁is-OR₄；

R₃Is unsubstituted or substituted by C₁-C₈Alkyl radical, C₁-C₈Alkoxy radical, C₁-C₈Phenyl substituted 1 to 4 times with alkylthio and/or halogen; and is

R₄Is C₁-C₈Alkyl, phenyl or benzyl. For example, R₁is-OR₄. For example, R₂Is unsubstituted or substituted by halogen, C₁-C₈Alkyl and/or C₁-C₈Alkoxy is substituted 1 to 4 times phenyl. For example, R₃Is unsubstituted or substituted by C₁-C₈Phenyl substituted 1-4 times by alkyl. For example, monoacylphosphine oxides of the present invention are 2, 4, 6-trimethylbenzoylethoxyphenylphosphine oxide (CAS No. 84434-11-7) or 2, 4, 6-trimethylbenzoyldiphenylphosphine oxide (CAS No. 127090-72-6).

The compositions according to the invention may also employ other photoinitiators, for example alpha-hydroxyketone photoinitiators of formula III:

wherein

R₁₁And R₁₂Independently of one another are hydrogen, C₁-C₆Alkyl, phenyl, C₁-C₆Alkoxy, OSiR₁₆(R₁₇)₂or-O (CH)₂CH₂O)_q-C₁-C₆Alkyl, or

R₁₁And R₁₂Together with the carbon atom to which they are attached form a cyclohexyl ring;

q is a number from 1 to 20;

R₁₃is OH, C₁-C₁₆Alkoxy or-O (CH)₂CH₂O)_q-C₁-C₆An alkyl group;

R₁₄is hydrogen, C₁-C₁₈Alkyl radical, C₁-C₁₂Hydroxyalkyl radical, C₁-C₁₈Alkoxy, -OCH₂CH₂-OR₁₅、-CH＝CH₂、-C(CH₃)＝CH₂Or is

n is a number from 2 to 10;

R₁₅is hydrogen, -COCH ═ CH₂or-COC (CH)₃)＝CH₂；

R₁₆And R₁₇Independently of one another are C₁-C₈Alkyl or phenyl; and is

G₃And G ₄Independently of one another, are end groups of the polymer structure, preferably hydrogen or methyl.

The alpha-hydroxyketone photoinitiators of interest are those in which R is₁₁And R₁₂Independently of one another are hydrogen, C₁-C₆Alkyl or phenyl, or R₁₁And R₁₂Together with the carbon atom to which they are attached form a cyclohexyl ring, R₁₃Is OH, and R₁₄Is hydrogen, C₁-C₁₂Alkyl radical, C₁-C₁₂Alkoxy, -OCH₂CH₂OR₁₅、-C(CH₃)＝CH₂Or is either

Suitable as alpha-hydroxyketone photoinitiators are, for example, those in which R is₁₁And R₁₂Independently of one another, methyl or ethyl, or R₁₁And R₁₂Together with the carbon atom to which they are attached form a cyclohexyl ring, R₁₃Is hydrogen and R₁₄Is hydrogen, C₁-C₄Alkyl radical, C₁-C₄Alkoxy or-OCH₂CH₂And (5) OH. Also of interest are compounds wherein R₁₄Is composed of

For example, suitable alpha-hydroxyketone photoinitiators are

Alpha-hydroxy-cyclohexyl-phenyl-ketone,

2-hydroxy-2-methyl-1-phenyl acetone,

2-hydroxy-2-methyl-1- (4-isopropylphenyl) propanone,

2-hydroxy-2-methyl-1- (4-dodecylphenyl) propanone

2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl ] -phenyl } -2-methyl-propan-1-one and

2-hydroxy-2-methyl-1- [ (2-hydroxyethoxy) phenyl ] propanone.

The alpha-hydroxyketone photoinitiator according to the invention is, for example, alpha-hydroxycyclohexyl phenyl ketone or 2-hydroxy-2-methyl-1-phenyl-1-propanone. Straight-chain or branched alkyl is, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, isooctyl, hexyl, heptyl, octyl, nonyl, decyl or dodecyl. Likewise, alkoxy or alkylthio groups have the same straight or branched chain.

The photoinitiators according to the invention can be employed individually or as a blend in one or more combinations. Suitable photoinitiator blends (PI blends) are disclosed, for example, in U.S. patent No. 6,020,528 and U.S. patent application No. 60/498,848. PI (photoinitiator) blends of the present invention are, for example, mixtures of bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide (CAS number 162881-26-7) and 2, 4, 6-trimethylbenzoylethoxyphenylphosphine oxide (CAS number 84434-11-7) in a weight ratio of about 1: 11, 1: 10, 1: 9, 1: 8, or 1: 7.

Another particularly suitable PI blend is a mixture of bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide, 2, 4, 6-trimethylbenzoylethoxyphenylphosphine oxide and 2-hydroxy-2-methyl-1-phenyl-1-propanone (CAS number 7473-98-5) in a weight ratio of, for example, about 3: 1: 15 or 3: 1: 16 or 4: 1: 15 or 4: 1: 16. Another suitable PI blend is a mixture of bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide and 2-hydroxy-2-methyl-1-phenyl-1-propanone in a weight ratio of, for example, about 1: 3, 1: 4 or 1: 5. The acylphosphine oxides PI or PI blends of the present invention are present in the radiation curable composition at about 0.2 wt% to about 10 wt%, based on the weight of the composition. For example, the PI or PI blend is present at about 0.5 wt% to about 8 wt%, about 1 wt% to about 7 wt%, or about 2 wt%, 3 wt%, 4 wt%, 5 wt%, or 6 wt%, based on the weight of the radiation curable composition.

Other suitable photoinitiators according to the invention are, for example, other monoacylphosphine oxides or bisacylphosphine oxides, such as diphenyl-2, 4, 6-trimethylbenzoylphosphine oxide or bis (2, 6-dimethoxybenzoyl) -2, 4, 4-trimethylpentylphosphine oxide; alpha-hydroxy ketones, such as 1-hydroxycyclohexyl phenyl ketone or 2-hydroxy-1- [4- (2-hydroxyethoxy) phenyl ] -2-methyl-1-propanone; alpha-aminoketones, for example 2-methyl-1- [4- (methylthio) phenyl ] -2- (4-morpholinyl) -1-propanone, 2-benzyl-2- (dimethylamino) -1- [4- (4-morpholinyl) phenyl ] -1-butanone, 2- (4-methylbenzyl-2- (dimethylamino) -1- [4- (4-morpholinyl) phenyl ] -1-butanone or 2-benzyl-2- (dimethylamino) -1- [3, 4-dimethoxyphenyl ] -1-butanone, benzophenones, for example benzophenone, 2, 4, 6-trimethylbenzophenone, methyl benzophenone, 4-methylbenzophenone, 2-methoxycarbonylbenzophenone, 4 '-bis (chloromethyl) -benzophenone, 4-chlorobenzophenone, 4-phenylbenzophenone, 4' -bis (dimethylamino) -benzophenone, 4 '-bis (diethylamino) benzophenone, methyl 2-benzoylbenzoate, 3' -dimethyl-4-methoxybenzophenone, 4- (4-methylphenylsulfanyl) benzophenone, 2, 4, 6-trimethyl-4 '-phenyl-benzophenone or 3-methyl-4' -phenyl-benzophenone; ketal compounds, such as 2, 2-dimethoxy-1, 2-diphenyl-ethanone; and monomeric or dimeric phenylglyoxylates, such as methylphenylglyoxylate, 5' -oxo-bis (ethyleneoxydicarbonylphenyl) or 1, 2- (benzoylcarboxy) ethane.

Other suitable photoinitiators with or without acylphosphine oxide photoinitiators to be employed according to the present invention are, for example, the oxime esters disclosed in U.S. Pat. No. 6,596,445. Suitable oxime ester photoinitiators are, for example:

another class of suitable photoinitiators, with or without acylphosphine oxide photoinitiators according to the present invention, are for example phenylglyoxylates, e.g. as disclosed in us patent No. 6,048,660. For example, phenylglyoxylic esters of the formula:

wherein Y is C₁-C₁₂Alkylene, cyclohexylene, O, S or NR₃₀C interrupted one or more times₂-C₄₀Alkylene, and R₃₀Is hydrogen, C₁-C₁₂Alkyl or phenyl, preferably Y is CH₂CH₂-O-CH₂CH₂。

One or more of the above-described free radical photoinitiators may be used in the composition according to the invention in any suitable amount and may be selected individually or in combination with one or more of the types listed herein. In a preferred embodiment, the free radical photoinitiator component is present in an amount of from about 0.1% to about 10% by weight, more preferably from about 0.1% to about 5% by weight, more preferably from about 1% to about 5% by weight, relative to the total weight of the composition.

Additive agent

Additives are also commonly added to optical fiber coatings to achieve certain desired properties, such as improved shelf life, improved oxidation and hydrolytic stability of the coating, and the like. There are many different types of desirable additives, and the inventions discussed herein are not intended to be limited to these, however they are included in contemplated embodiments as they have the desired effect.

Examples of these are thermal inhibitors intended to prevent premature polymerization, exemplified by hydroquinone, hydroquinone derivatives, p-methoxyphenol, beta-naphthol, or sterically hindered phenols, such as 2, 6-di (tert-butyl) -p-cresol. The shelf life in the dark can be extended, for example, by using copper compounds (e.g., copper naphthenate, stearate, or octoate), phosphorus compounds (e.g., triphenylphosphine, tributylphosphine, triethyl phosphite, triphenyl phosphite, or tribenzyl phosphite), quaternary ammonium compounds (e.g., tetramethylammonium chloride or trimethylbenzylammonium chloride).

In order to prevent the entry of atmospheric oxygen during the polymerization, paraffin or similar waxy substances may be added; these substances migrate to the surface at the start of the polymerization due to their low solubility in the polymer and form a transparent surface layer which prevents the entry of air. An oxygen barrier layer may also be applied.

Light stabilizers which may be added are UV absorbers, for example the well-known commercial UV absorbers of the hydroxyphenyl benzotriazole, hydroxyphenyl benzophenone, oxamide or hydroxyphenyl-s-triazine type. Such compounds may be used alone or in mixtures with or without the use of sterically hindered, relatively non-basic amine light stabilizers (HALS). Sterically hindered amines are based, for example, on 2, 2, 6, 6-tetramethylpiperidine. UV absorbers and sterically hindered amines are, for example:

2- (2-hydroxyphenyl) -2H-benzotriazoles, such as the known commercially available hydroxyphenyl-2H-benzotriazoles and are described in U.S. patent nos. 3,004,896; 3,055,896, respectively; 3,072,585, respectively; 3,074,910, respectively; 3,189,615, respectively; 3,218,332, respectively; 3,230,194, respectively; 4,127,586, respectively; 4,226,763, respectively; 4,275,004, respectively; 4,278,589, respectively; 4,315,848, respectively; 4,347,180, respectively; 4,383,863, respectively; 4,675,352, respectively; 4,681,905, respectively; 4,853,471; 5,268,450, respectively; 5,278,314, respectively; 5,280,124, respectively; 5,319,091, respectively; 5,410,071, respectively; 5,436,349, respectively; 5,516,914, respectively; 5,554,760, respectively; 5,563,242, respectively; 5,574,166, respectively; 5,607,987, respectively; 5,977,219 and 6,166,218, for example, 2- (2-hydroxy-5-methylphenyl) -2H-benzotriazole, 2- (3, 5-di-tert-butyl-2-hydroxyphenyl) -2H-benzotriazole, 2- (2-hydroxy-5-tert-butylphenyl) -2H-benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) -2H-benzotriazole, 5-chloro-2- (3, 5-di-tert-butyl-2-hydroxyphenyl) -2H-benzotriazole, 5-chloro-2- (3-tert-butyl-2-hydroxy-5-methylphenyl) -2H-benzotriazole, 2-hydroxy-5-methylphenyl-2H-benzotriazole, 2-hydroxy-methyl-phenyl-2H-benzotriazole, 2- (3-sec-butyl-5-tert-butyl-2-hydroxyphenyl) -2H-benzotriazole, 2- (2-hydroxy-4-octyloxyphenyl) -2H-benzotriazole, 2- (3, 5-di-tert-amyl-2-hydroxyphenyl) -2H-benzotriazole, 2- (3, 5-bis-alpha-cumyl-2-hydroxyphenyl) -2H-benzotriazole, 2- (3-tert-butyl-2-hydroxy-5- (2- (omega-hydroxy-octa- (ethyleneoxy) carbonyl-ethyl) -, phenyl) -2H-benzotriazole, 2- (3-dodecyl-2-hydroxy-5-methylphenyl) benzotriazole ) -2H-benzotriazole, 2- (3-tert-butyl-2-hydroxy-5- (2-octyloxycarbonyl) ethylphenyl) -2H-benzotriazole, dodecylated 2- (2-hydroxy-5-methylphenyl) -2H-benzotriazole, 2- (3-tert-butyl-2-hydroxy-5- (2-octyloxycarbonylethyl) phenyl) -5-chloro-2H-benzotriazole, 2- (3-tert-butyl-5- (2- (2-ethylhexyloxy) -carbonylethyl) -2-hydroxyphenyl) -5-chloro-2H-benzotriazole, 2- (3-tert-butyl-2-hydroxy-5- (2-methoxycarbonyloxy) -2H-benzotriazole Carbonylethyl) phenyl) -5-chloro-2H-benzotriazole, 2- (3-tert-butyl-2-hydroxy-5- (2-methoxycarbonylethyl) phenyl) -2H-benzotriazole, 2- (3-tert-butyl-5- (2- (2-ethylhexyloxy) carbonylethyl) -2-hydroxyphenyl) -2H-benzotriazole, 2- (3-tert-butyl-2-hydroxy-5- (2-isooctyloxycarbonylethyl) phenyl-2H-benzotriazole, 2' -methylene-bis (4-tert-octyl- (6-2H-benzotriazol-2-yl) phenol); and pharmaceutically acceptable salts thereof, 2- (2-hydroxy-3-alpha-cumyl-5-tert-octylphenyl) -2H-benzotriazole, 2- (2-hydroxy-3-tert-octyl-5-alpha-cumylphenyl) -2H-benzotriazole, 5-fluoro-2- (2-hydroxy-3, 5-di-alpha-cumylphenyl) -2H-benzotriazole, 5-chloro-2- (2-hydroxy-3-alpha-cumyl-5-tert-octylphenyl) -2H-benzotriazole, 2-hydroxy-3-alpha-cumylphenyl-2H-benzotriazole, 2-hydroxy-3-cumyl-5-tert-octylphenyl-benzotriazole, 2-hydroxy-3-cumyl-2H-benzotriazole, 2-hydroxy-, 2- (3-tert-butyl-2-hydroxy-5- (2-isooctyloxycarbonylethyl) phenyl) -5-chloro-2H-benzotriazole, 5-trifluoromethyl-2- (2-hydroxy-3-. alpha. -cumyl-5-tert-octylphenyl) -2H-benzotriazole, 5-trifluoromethyl-2- (2-hydroxy-3, 5-di-tert-octylphenyl) -2H-benzotriazole, 3- (5-trifluoromethyl-2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyhydrocinnamic acid methyl ester, 2-hydroxy-5- (2-isooctyloxycarbonylethyl) phenyl) -5-chloro-2H-benzotriazole, 5-trifluoromethyl-2- (2-hydroxy-5-tert-octylphenyl) -2H-benzotriazole, 5-trifluoromethyl, 5-Butylsulfonyl-2- (2-hydroxy-3-. alpha. -cumyl-5-tert-octylphenyl) -2H-benzotriazole, 5-trifluoromethyl-2- (2-hydroxy-3-. alpha. -cumyl-5-tert-butylphenyl) -2H-benzotriazole, 5-trifluoromethyl-2- (2-hydroxy-3, 5-di-alpha-cumylphenyl) -2H-benzotriazole, 5-butylsulfonyl-2- (2-hydroxy-3, 5-di-tert-butylphenyl) -2H-benzotriazole and 5-phenylsulfonyl-2- (2-hydroxy-3, 5-di-tert-butylphenyl) -2H-benzotriazole.

2-hydroxybenzophenones, for example the 4-hydroxy derivative, the 4-methoxy derivative, the 4-octyloxy derivative, the 4-decyloxy derivative, the 4-dodecyloxy derivative, the 4-benzyloxy derivative, the 4, 2 ', 4' -trihydroxy derivative and the 2 '-hydroxy-4, 4' -dimethoxy derivative.

Esters of substituted and unsubstituted benzoic acids, for example 4-tert-butylphenyl salicylate, phenyl salicylate, octylphenyl salicylate, dibenzoyl resorcinol, bis (4-tert-butylbenzoyl) resorcinol, benzoyl resorcinol, 2, 4-di-tert-butylphenyl 3, 5-di-tert-butyl-4-hydroxybenzoate, hexadecyl 3, 5-di-tert-butyl-4-hydroxybenzoate, octadecyl 3, 5-di-tert-butyl-4-hydroxybenzoate, 2-methyl-4, 6-di-tert-butylphenyl 3, 5-di-tert-butyl-4-hydroxybenzoate.

Other additives

To accelerate the photopolymerization, accelerators, coinitiators and autooxidants, for example mercaptans, thioethers, disulfides and phosphines, can be added, as described, for example, in EP-A-438123 and GB-A-2180358.

Photopolymerization can also be accelerated by the addition of photosensitizers that change or broaden the spectral sensitivity. These photosensitizers are, in particular, aromatic carbonyl compounds, such as benzophenone derivatives, thioxanthone derivatives, anthraquinone derivatives and 3-acylcoumarin derivatives, and also 3- (aroylmethylene) thiazolines (3- (arylmethyl) thiazolines), and also eosin, rhodamine and erythrosine dyes. Alternatively, non-aromatic carbonyl compounds may be used. An example of a non-aromatic carbonyl group is dimethoxyanthracene.

The curing process can be assisted in particular by: compositions that are colored (e.g., with titanium dioxide); and also by adding components that form free radicals under thermal conditions, such as azo compounds (e.g., 2' -azobis (4-methoxy-2, 4-dimethylvaleronitrile), triazenes, diazo sulfides, pentazadienes) or peroxy compounds (e.g., hydroperoxides or peroxycarbonates, such as t-butyl hydroperoxide), as described in U.S. Pat. No. 4,753,817. Further suitable for this purpose include benzopinacol compounds.

The novel compositions may also comprise photoreducible dyes, such as xanthene, benzoxanthene, benzothioxanthene, thiazine, pyronine, porphyrin or acridine dyes which can be cleaved by radiation and/or trihalomethyl compounds. Similar compositions are described, for example, in U.S. patent No. 5,229,253.

Other conventional additives may be used depending on the intended application. Examples include optical brighteners, fillers, pigments, dyes, wetting agents or levelling assistants. For example, as described in U.S. patent No. 5,013,768, thick and pigmented coatings may also contain glass beads or powdered glass fibers.

One or more of the above additives may be used in the composition according to the invention in any suitable amount and may be selected individually or in combination with one or more of the types listed herein. In a preferred embodiment, the additive component is present in an amount of about 0.01 wt% to about 5 wt%, more preferably about 0.1 wt% to about 2 wt%, relative to the total weight of the composition. According to another embodiment, one or more of the above additives are included in an amount of about 1% to about 5% by weight.

Configuring a primary coating composition to achieve improved thermal resistance

The inventors have now found that conventional radiation curable primary coating compositions of the type described herein, especially the oligomeric components, are generally characterized by non-newtonian rheology. That is, they are shear thinning or exhibit a decrease in shear viscosity at high shear rates. Furthermore, such materials are highly temperature dependent; that is, the viscosity of the composition is significantly affected by its temperature. The inventors have found that the combination of these characteristics results in a material that is particularly sensitive to high temperature, high shear rate conditions, such as those experienced in high draw speed or low helium optical fiber coating processes.

This particular sensitivity produces coatings that become exponentially adversely affected by increasing levels of thermal shock or stress to the primary coating, as exemplified by: wherein relatively hot as-drawn glass fibers moving at a high rate are contacted with a relatively cold static radiation curable primary coating composition. In particular, considering the temperature dependence of the shear viscosity, the so-called viscous heating effect creates a thin layer of low viscosity fluid near the fiber when applied to a hot glass optical fiber. This phenomenon may be conceptually similar to the rapid insertion of a hot knife through the butter, resulting in a strong reduction in the drag capacity of the resin in the corresponding applicator die, and a strong reduction in the coating thickness.

Furthermore, the inventors have found that conventional fiber coating applicator die designs leave a significant portion of the die volume in the closed loop vortex. This results in a longer residence time of the average fraction (average quantum) of the primary coating composition in the die before application. Such die designs exacerbate the above problems because they lead to the following phenomena: although the work done by viscous heating raises the local temperature of the resin, the material inside the vortex is not refreshed and the temperature will be raised until an equilibrium is reached between cooling by conduction of heat in the fluid and heating by viscous dissipation.

The foregoing phenomenon causes the following problems: impermissibly thin primary coatings, primary coatings with run-out/concentricity issues, primary coatings with bubbles or defects, or those that do not adhere properly to the glass, resulting in delamination issues.

In view of an understanding of the foregoing mechanisms, the inventors have now recognized that the suitability of a primary coating composition for use in high draw speed or low helium optical fiber coating processes can be improved by reducing the viscosity sensitivity of the primary coating composition as a function of temperature. That is, if the relative viscosity of such materials is plotted as a function of temperature, the materials should exhibit a flattened or reduced slope.

The inventors have found that proper "curve flattening" can be achieved by tuning the viscosity ratio of the composition. As used hereinThe viscosity ratio is the steady state shear viscosity (at a shear rate of 10 s) of the same composition at two different temperatures, wherein the first temperature is lower than the second temperature^-1Time). As used herein, unless otherwise indicated, "viscosity" and all qualifiers (e.g., "first viscosity," "second viscosity," or "third viscosity," etc.) should be considered to mean at 10s ^-1And all units are expressed in pascal seconds unless otherwise indicated. In one embodiment, the viscosity ratio is the viscosity of the composition at 25 ℃ divided by the viscosity of the same composition at 55 ℃. In another embodiment, the viscosity ratio is the viscosity of the composition at 25 ℃ divided by the viscosity of the same composition at 85 ℃. Although the temperature conditions for the optical fiber coating process will change at high draw speeds or low helium utilization, 55 ℃ was chosen because it is the operating temperature at which failure of the existing primary coating composition is observed. 85 ℃ is considered an even more efficient label because: (1) this higher value will better distinguish the minimum performance coating from the high performance coating, and (2) it reflects the temperature to which the coating will predictably increase under the more demanding optical fiber processing conditions required for higher throughput and/or reduced helium consumption. Thus, compositions having viscosity ratios below selected values may be sufficiently heat resistant to be suitable for high draw down speed/low helium coating processes.

In embodiments where 85 ℃ is selected as the upper limit in determining temperature sensitivity, the ratio of the viscosity at 25 ℃ to the viscosity at 85 ℃ of the composition is less than 15, or less than 14.4, or less than 13.9, or less than 13, or less than 12, or less than 11, or less than 10, or less than 9, or less than 7. In one embodiment, the viscosity ratio at 25 ℃ to 85 ℃ is in the range from 5 to 15, or from 5 to 14.4, or from 5 to 13.9, or from 5 to 13, or from 5 to 9, or from 5 to 7, or from 6 to 15, or from 6 to 14.4, or from 6 to 13.9, or from 6 to 13, or from 6 to 9, or from 6 to 7, or from 6.4 to 15, or from 6.4 to 14.4, or from 6.4 to 13.9, or from 6.4 to 13, or from 6.4 to 9, or from 6.4 to 7, or from 7 to 15, or from 7 to 14.4, or from 7 to 13.9, or from 7 to 13, or from 7 to 12, or from 7 to 11, or from 7 to 10, or from 7 to 9. The above values and ratios may be exact, or alternatively relate to approximations (i.e., ± 5%, or "about") of each recited value.

In embodiments where 55 ℃ is selected as the upper limit in determining temperature sensitivity, the ratio of the viscosity at 25 ℃ to the viscosity at 55 ℃ of the composition is less than about 4.7, or less than about 4.6, or less than about 4.4, or less than about 4.2, or less than about 4.0, or less than about 3.5. In one embodiment, the viscosity ratio at 25 ℃ to 55 ℃ is in the range of about 2 to about 4.7, or about 3 to about 4.7, or about 2 to about 4.6, or about 3 to about 4.6, or about 2 to about 4.4, or about 3 to about 4.4, or about 2 to about 4.2, or about 3 to about 4.2, or about 2 to about 4.0, or about 3 to about 4.0, or about 2 to about 3.5, or about 3 to about 3.5. The above values and ratios may be exact, or alternatively relate to approximations (i.e., ± 5%, or "about") of each recited value.

If the viscosity ratio is too high, as has been observed in all of the heretofore existing optical fiber primary coatings, the composition is characterized by an undesirably significant sensitivity to temperature changes, which will result in poor glass application and/or curing performance at high temperature/high speed processing. Therefore, the composition should be tuned according to the methods described herein to ensure that the viscosity ratio is as low as possible while maintaining feasibility as an optical fiber coating.

In addition to having the necessary viscosity ratio, the primary coating composition should also have a sufficiently high viscosity at a relatively high operating temperature (e.g., 55 ℃). That is, the primary coating must have both a sufficiently low slope in terms of temperature/viscosity relationship and a suitably high "y-intercept". A primary coating composition having a sufficiently low viscosity ratio (i.e., relatively temperature insensitive or non-temperature/viscosity dependent) may not be suitable for coating an optical fiber if it has an initial viscosity that is too low for a viable use. Thus, according to certain embodiments, the inventors have found that another limitation of the heat resistant primary coating compositions according to the present invention is that such compositions should have a viscosity of at least 0.01 pascal-seconds (Pa · s), or greater than 0.10Pa · s, or less than 20Pa · s, or less than 1Pa · s, or between about 0.01Pa · s and about 20Pa · s, or between about 0.01Pa · s and about 1Pa · s, or from about 0.03Pa · s to about 0.8Pa · s, or from about 0.03Pa · s to about 0.5Pa · s, or from about 0.03Pa · s to about 0.4Pa · s, or from about 0.05Pa · s to about 1Pa · s, or from about 0.05Pa · s to about 0.5 · s, or from about 0.1Pa · s to about 1.8 Pa · s, or from about 0.05Pa · s to about 0.5 · s, or from about 0.1Pa · s. In one embodiment, the application temperature is 55 ℃. In another embodiment, the application temperature is 85 ℃.

In a preferred embodiment, the viscosity of the composition is between 0.03Pa · s and 6Pa · s, or from 0.05Pa · s to 5Pa · s, or from 0.1Pa · s to 3Pa · s, at an application temperature of 55 ℃. In a preferred embodiment, the viscosity of the composition is between 0.01Pa · s and 2Pa · s, or from 0.03Pa · s to 1.5Pa · s, or from 0.05Pa · s to 1Pa · s, at an application temperature of 85 degrees celsius. Also, in a preferred embodiment, the viscosity of the composition is between 0.1 and 20 pas, or from 0.5 to 15 pas, or from 1 to 10 pas, or from 5 to 10 pas at an application temperature of 25 degrees celsius.

The viscosity of a composition at room temperature may also be a suitable indicator as to whether the composition will have a suitable resistance to flow at a specified application temperature. A composition with too low a viscosity at room temperature will more likely be insufficiently viscous at the application temperature. Thus, in one embodiment, the viscosity of the primary coating composition is greater than 4Pa · s, or greater than 5Pa · s, or from 5Pa · s to 100Pa · s, or from 5Pa · s to 50Pa · s, or from 5Pa · s to 20Pa · s, or from 5Pa · s to 12Pa · s, or from 5Pa · s to 10Pa · s, or from 8Pa · s to 50Pa · s, or from 8Pa · s to 20Pa · s, or from 8Pa · s to 12Pa · s, when measured at 25 ℃.

The curve flattening effect of the primary coating composition of the present invention has also been found herein to correlate with a variety of other coating characteristics. The inventors have found that there is a correlation between properties such as the dielectric constant of the composition, its refractive index, its liquid glass transition temperature, and the relative thermal sensitivity (or insensitivity) of such compositions. Surprisingly, the inventors have found that there is a strong correlation between the liquid glass transition temperature of the coating composition and its viscosity ratio; that is, the lower the liquid glass transition temperature of the selected composition, the less temperature sensitive it becomes (as reflected by its relative ability to resist changes in viscosity when heated).

The inventors have found that the extent to which a primary coating composition is suitable for use in a high draw speed/low helium optical fiber coating process is related to its expected time-temperature stacking properties as measured by the Williams-Landel-Ferry (or WLF) equation. The temperature dependence of the relaxation time (tau) associated with the glass transition of amorphous polymeric materials follows the so-called Williams, Landel and ferry (wlf) relationship:

where τ (T) is the relaxation time of the glass transition of the polymeric material at the temperature T, τ (T) _ref) Is the reference temperature T_refRelaxation time of the glass transition of the polymer material, and C₁And C₂Is a constant. C₁And C₂The value of (d) depends on the selected reference temperature. It has been described in the literature that when the reference temperature is chosen equal to the glass transition temperature (T)_g) When there is a 'universal' value of C₁17.44 and C₂51.6 is useful for a wide range of polymeric materials, where T is_gIs obtained by dynamic scanning calorimetry in McCrum, Read and Williams, Electron and direct Effects in Polymeric Solids, John Wiley&Sons, New York, 1967. However, for the inventors' findings, the viscosity of the uncured optical fiber coating resin formulation can be suitably described in the following manner:

where eta (T) is the viscosity of the liquid at the temperature T (unless otherwise stated, e.g.T, as used herein, is expressed in degrees Celsius), η (T)_g) Is a glass transition temperature T as determined using DSC_gViscosity of (b), constant C₁Is a fixed value of 15 and C₂Is a fitting parameter that varies within a limited range of values between 35 and 45. Therefore, the WLF equation for liquid resin viscosity follows the same temperature dependence as the relaxation time of the glass transition, with similar C ₁Value and slightly lower C₂The value is obtained. The inventors have also found that a fixed value of 37.5 is selected in this equation for C₂The glass transition temperature (Tg, rheo) of the liquid resin can be determined from the resin viscosity versus temperature, which is particularly useful if no data from DSC is available. Consider that C is found when using actual Tg data from DSC₂The range of values is limited, which means that the glass transition temperature as determined from rheology is consistent with the value from DSC within at most ± 5 ℃, which here would be considered to be of acceptable accuracy.

Thus, to calculate Tg from rheology, the following normalized equation can be applied:

the uncured liquid optical fiber coating resin formulation according to the invention has a lower sensitivity of the resin viscosity to temperature as measured by the ratios η (25 ℃)/η (55 ℃) and/or η (25 ℃)/η (85 ℃), compared to the state of the art resin formulations. For this purpose, it is useful to convert equation (3) from Tg, rheo as reference temperature to a reference temperature of 25 ℃.

Converting the WLF equation to a different reference temperature can be done by the following equation:

C_{1，Tref＝25℃}×C_{2，Tref＝25℃}＝C_{1，Tref＝Tg，rheo}×C_{2，Tref＝Tg，rheo} (5)

and

C_{2，Tref＝25℃}-25＝C_{2，Tref＝Tg，rheo}-Tg，rheo (6)。

by including equations (5) and (6), the general WLF equation (3) with Tg-rheo as the reference temperature and the equivalent equation (4) with 25 ℃ as the reference temperature can be combined into a single free parameter equation to fit a relative viscosity curve at the reference temperature of 25 ℃ to the Tg, rheo:

The foregoing is surprising and has directed the inventors to solve the problem of providing compositions that are more processable at higher line speeds and/or lower helium contents by formulating in the opposite direction to the previously considered suitable formulation methods. A conventional way to ensure that the coating has a higher viscosity at high temperatures is to increase the viscosity of the resin. Such methods may be realized, inter alia, via: increasing the relative amount of higher molecular weight components (e.g., oligomers), or by selecting reactive diluent monomers with higher viscosities. However, such an approach will typically result in an increase in the liquid glass transition temperature (Tg, rheo) of the coating. In view of the general WLF description of viscosity versus temperature according to equation (3), the inventors have found that such an approach would unexpectedly increase the temperature sensitivity of the composition, resulting in a coating that, despite having an initially higher viscosity at room temperature, would more readily degrade to a low viscosity resin that is not suitable for application under higher thermal loads. Thus, the inventors have now specified the following paradoxical pathways: the resins are formulated in directions that act to reduce or maintain the viscosity at room temperature (relative to the best solutions currently known) and to reduce the glass transition temperature of the liquid coating to yield reduced overall viscosity sensitivity and to ensure improved processability at higher temperatures.

In addition to exploring the causes of these phenomena, the inventors have also devised solutions that enable the skilled person, when following certain guidelines specified herein (and further illustrated in non-limiting examples), to easily tune or configure radiation curable primary coating compositions within certain parameters, including viscosity ratio and viscosity at 25 ℃, without undue experimentation, in order to mitigate the inherent hazards associated with high draw speed/low helium processing environments. Thus, the inventors have surprisingly discovered that if certain properties of the resin are tuned, the primary coating composition can be configured to achieve improved thermal resistivity and, in turn, suitability for use with optical fiber coating processes operating at high line speeds or low helium applications. Several approaches can be used to formulate to meet this criteria, including: (1) selecting a reactive diluent monomer having a lower liquid glass transition temperature; and/or (2) selecting an oligomer having a lower liquid glass transition temperature. Although the glass transition temperature of the uncured monomer is generally not specified by the manufacturer or readily determinable, as described above, the viscosity of the monomer can be used as a first guide for selecting the appropriate type. That is, monomers having low viscosity generally also have low glass transition temperatures.

In addition, the inventors have determined that the relative polarity of the monomers is also a good indicator of their ability to reduce the glass transition temperature of the compositions with which they are associated. The inventors have found that more polar monomers have been observed to beneficially contribute by tending to reduce the liquid glass transition temperature of their associated compositions relative to non-polar monomers without a concomitant reduction in the overall viscosity of the compositions. As mentioned elsewhere herein, the relative polarity can be understood by the calculated boltzmann average dipole moment of the monomers.

Meanwhile, in the case of oligomers, the inventors have found that lower oligomer Tg, rheo, can be obtained by selecting building blocks (polyols, isocyanates and acrylate end-caps) with low glass transition temperatures. Since diols generally have the lowest glass transition temperature, it is preferred in one embodiment to select diols having a number average molecular weight of 4000g/mol or more-in particular if it is desired to simultaneously ensure sufficiently high initial viscosity values-and to mix these diols with appropriate molar ratios of (di) isocyanates in order to achieve polyether-polyurethane-acrylate oligomers containing mono-blocks, di-blocks or higher numbers of polyol blocks. In addition, the inventors have found that oligomer chemistry has a significant effect on the elasticity of the liquid, as measured by the so-called steady state compliance (Je) of the liquid. The narrow distribution of the oligomeric diol (e.g., from anionic polymerization) provides a less elastic liquid. In addition, polyols having low entanglement molecular weights, including, for example, PTGL and Polytetrahydrofuran (PTHF), result in higher liquid elasticity. In contrast, examples of liquids having a high entanglement molecular weight and thus less elasticity include polypropylene glycol (PPG) and ethylene oxide-butylene oxide copolymer (EOBO).

Meanwhile, in order to control the viscosity, the amount or properties of the reactive diluent monomer may be appropriately changed. Since this component is not expected to have a significant impact on the elasticity of the composition, once a sufficient temperature sensitivity or viscosity ratio is achieved, this component can be tuned to achieve the appropriate starting viscosity as described and claimed herein.

First, due to the significant dilution effect of several preferred monomers having low liquid glass transition temperatures, it is often necessary or necessary to incorporate large amounts of oligomeric components. The high amount of oligomer also helps to introduce good mechanical properties in the primary coating thus cured, so there are several reasons to ensure that high levels of oligomer are present in several embodiments of the invention. Thus, in a preferred embodiment, the radiation curable composition contains at least 50 wt.% of the reactive oligomer component, or at least 55 wt.% of the reactive oligomer component, or at least 60 wt.% of the reactive oligomer component, or at least 65 wt.% of the reactive oligomer component, or at least 70 wt.% of the reactive oligomer component, or 45-85 wt.% of the reactive oligomer component, or 55 wt.% to 80 wt.% of the reactive oligomer component, or 60 wt.% to 85 wt.% of the reactive oligomer component, or 60 wt.% to 80 wt.% of the reactive oligomer component.

Viscosity can also be controlled by oligomer selection and/or synthesis methods. In particular, the inventors have also surprisingly found that, depending on the method of oligomer synthesis technique employed, the viscosity of the composition can be varied independently of the overall temperature resistance of the composition associated with such oligomers. In particular, the inventors have observed that oligomers synthesized with certain molecular weight distributions tend to produce oligomers with higher viscosities than the same theoretical oligomers created by synthesis methods using other molecular weight distributions, without inducing a significant effect on the Tg, rheo of the radiation curable compositions with which they are associated. The inventors have observed that, as a non-limiting example, oligomers synthesized by the "inside-out" method produce such an optimal molecular weight distribution as compared to the same oligomers created by the "outside-in" synthesis method. Without wishing to be bound by any theory, the inventors believe that this occurs because such processes tend to create a distribution containing a higher fraction of oligomers with a larger molecular weight. It is believed that while such variants are capable of imparting viscosity changes, they do not significantly affect the overall liquid glass transition temperature due to their relatively low representation by weight relative to all oligomer variants present.

This strategy can be helpful to the formulator of radiation curable primary compositions for optical fiber coating applications because it enables the use of a wider class of formulation ingredients that would lower the liquid glass transition temperature of the composition, but are otherwise unsuitable for use because they result in compositions that are not sufficiently viscous. Rather, this understanding also enables formulators to reduce viscosity without significant changes in relative temperature resistance as desired.

The inventors have found that a suitable way to characterize oligomers that tend to produce this desired effect is that they define those oligomers with a defined Relative High Molecular Weight Ratio (RHMWR). As used herein, RHMWR is determined by: derived values of peak molecular weight (Mp), Z-average molecular weight (Mz), and number-average molecular weight (Mn) are calculated via formula (9):

wherein Mp, Mz and Mn are determined by Size Exclusion Chromatography (SEC) methods.

Thus, in a preferred embodiment, the RHMWR value of the reactive oligomer is between-0.3 and 3. In one embodiment, the reactive oligomer has an RMWR value of greater than-0.3, or greater than-0.1, or greater than 0, or greater than 0.05. In one embodiment, the reactive oligomer has an RHMWR value of less than 3, or less than 2, or less than 1, or less than 0.8.

Any oligomer synthesis technique that tends to produce oligomers within this above-described range is expected to promote higher viscosities without adversely affecting the liquid glass transition temperature. The inventors have also surprisingly found that polydispersity is not a good indicator of this phenomenon, as it has been observed that differently behaving oligomers with different RHMWR values may still have relatively similar polydispersity values. This is believed to be because, for the purposes of the present invention, the relevant differences in molecular weight distribution are most relevant in terms of the larger (e.g., z-1 and z +1) moments (momentions) of the molecular weight distribution. Other methods should be used since lower moments (e.g., Mw and Mn) are not sensitive enough to indicate this subtle but significant difference.

The inventors have also surprisingly found that fillers can be employed to increase the viscosity without sacrificing the viscosity ratio of the compositions with which they are associated.

The foregoing configuration guidelines may be utilized alone or in combination of two or more and in no way represent an exhaustive list. Other things, including additional known formulation guidelines, are understood by those skilled in the art and may be urgently used in view of the application and the particular requirements of the process associated with the primary coating composition.

A fourth aspect of the present invention is a method for producing a coated optical fiber, the method comprising the steps of: drawing a glass optical fiber through a drawing tower; applying a primary coating composition onto a surface of the glass optical fiber; optionally, applying a dose of ultraviolet light sufficient to at least partially cure the primary coating composition; applying a secondary coating composition to the primary coating composition; exposing a primary coating composition and a secondary coating composition to at least one radiation source capable of emitting ultraviolet radiation to affect curing of the primary coating composition and the secondary coating composition to form a cured primary coating on a surface of the optical fiber, and a cured secondary coating on a surface of the cured primary coating; wherein the primary coating composition comprises: a reactive oligomer comprising at least one polymerizable group and a backbone derived from a diol comprising polypropylene glycol; a reactive diluent monomer; and one or more photoinitiators; wherein the radiation curable composition has a liquid glass transition temperature (Tg, rheo), a first viscosity at 25 degrees celsius (° c), a second viscosity at 55 ℃, and a third viscosity at 85 ℃; wherein the radiation curable composition has a Tg, rheo of less than-81.5 ℃, or from-120 ℃ to-80 ℃, or from-115 ℃ to-80 ℃, or from-110 ℃ to-80 ℃, or from-100 ℃ to-80 ℃, or from-120 ℃ to-82 ℃, or from-115 ℃ to-82 ℃, or from-110 ℃ to-82 ℃, or from-100 ℃ to-82 ℃, or from-120 ℃ to-85 ℃, or from-115 ℃ to-85 ℃, or from-110 ℃ to-85 ℃, or from-100 ℃ to-85 ℃, or from-120 ℃ to-90 ℃, or from-115 ℃ to-90 ℃, or from-110 ℃ to-90 ℃, or from-100 ℃ to-90 ℃; or from-120 ℃ to-97 ℃, or from-113 ℃ to-97 ℃; and/or wherein the ratio of the first viscosity to the third viscosity is less than about 15, or less than about 14.4, or less than about 13.9, or less than about 13, or less than about 9, or less than about 7.

The improved resins of the present invention may be formulated via selection of the components specified herein above, and further easily tuned by one of ordinary skill in the art to which the invention applies by following the formulation guidelines herein and by inference based on the general methods employed in the embodiments illustrated in the examples below. The following examples further illustrate the invention but, of course, should not be construed as in any way limiting its scope.

Examples

These examples illustrate embodiments of the invention. Tables 1A and 1B describe the various components of the compositions used in this example. Tables 2A and 2B describe the relative amounts of reagents used to synthesize the oligomers used in this example described in tables 1A and 1B. Tables 2C and 2D represent further evaluations of selected reactive diluent monomers and reactive oligomers, respectively.

TABLE 1A-oligomer component

TABLE 1B-other formulation Components

TABLE 2A-oligomer reactants

TABLE 2B-oligomer reactants, sequence

Synthesis of oligomers 1 to 5

First, after measurements to ensure the amounts specified in table 2A above, the relevant polyols (Arcol Polyol PPG 2000 for oligomer 1, Acclaim 8200 for oligomers 2 to 4, and Acclaim 4200 for oligomer 5) were added under a dry air interlayer (air blanket) to a clean and dry flask, after which a specified amount of inhibitor (BHT food grade) was added. Next, the indicated amounts of isocyanate component (IPDI for oligomers 2-4; Mondur TDS II grade for oligomers 1 and 5) were added, after which the indicated amounts of acrylic acid and 2-ethylhexanol (included only in oligomer 1 and oligomer 5) were subsequently added. These reagents were mixed and stirred for about 15 minutes. Next, the indicated amount of the relevant catalyst (DBTDL for oligomers 1-4, Coscat 83 for oligomer 5) was added to the same flask and mixed for approximately 15 minutes. The resulting mixture was then reacted in a heating mantle at 60 ℃ for 1 hour.

After the 1 hour reaction, the isocyanate (NCO) content was measured by potentiometric titrator to ensure that it was within 10% of the theoretical isocyanate content value, which can be deduced from the amounts specified in table 2A above, for each oligomer. After the appropriate isocyanate content was confirmed, an appropriate amount of hydroxyethyl acrylate was added to each oligomer, after which the resulting mixture was allowed to react at 85 ℃ for 1 hour. Here, the isocyanate content is checked again via potentiometric titration; if the isocyanate content exceeds 10% of theory, the mixture is returned to the reaction chamber in increments of another 15 minutes (again at 85 ℃) and checked again, and the procedure is repeated until the isocyanate content falls within the desired range.

Synthesis of oligomers 6 to 10

For this "outside-in" synthesis, designated as "O/I" in Table 2B, the following synthesis steps were used. First, the relevant diisocyanate (H12 MDI, PDI, TMDI, HDI or IPDI as shown in table 2B) and BHT were charged into a 500ml reactor (equipped with a stirrer, a lean air inlet, a dropping funnel and a condenser) and heated to 60 ℃. The reactor containing the heated mixture was then purged with oxygen-depleted air (consisting of nitrogen and oxygen in a 3: 1 flow ratio). The mixture was kept at a temperature of 60 ℃ for 10 minutes. Next, a certain amount of HEA (specified in table 2B as per the examples) was charged together with the amount of DBTDL (1) specified in table 2B and added dropwise to the same reactor maintained at 60 ℃. After the addition of HEA, the temperature was kept for a further 1 hour. After 1 hour, a small sample was taken and the NCO content was measured by potentiometric titrator to ensure that the NCO content was within ± 0.2% of the theoretical isocyanate content value, which can be deduced from the amounts specified in table 2B for each oligomer. If it is determined that the content is not within the permissible range, the reaction is continued at 60 ℃ with subsequent additional measurements every 15 minutes until an acceptable NCO content value is reached.

In the event that an acceptable NCO content value is reached, Acclaim 4200 polyol is then loaded into a feed vessel along with an additional amount of DBTDL (as designated by the example as DBTDL (2) in table 2B), after which the polyol/DBTDL combination is added dropwise to the reactor containing the aforementioned components. The reactor was kept at 60 ℃ for a further 1 hour. At that timeAfter this period, the reactor was further heated to 85 ℃ and held at this temperature for a further 2 hours. Beginning at the end of the additional 2 hour period, the NCO content is again checked to ensure that NCO is present in an amount of less than 0.1% relative to the total weight of the composition. By verifying the NCO (located at about 2200-^-1At) the corresponding FT-IR spectral peak has completely disappeared to check this. Additional checks will then be continued every hour until the NCO content has dropped to the maximum allowable level. Finally, the resulting synthetic oligomer was slowly cooled and discharged for use in experiments described elsewhere herein.

Synthesis of oligomers 11 to 12

For this "inside-out" synthesis, designated as "I/O" in Table 2B, the following synthesis steps were used. First, the indicated amounts of the relevant diisocyanate (IPDI for oligomer 11 or PDI for oligomer 12, in the amounts indicated in table 2B) and BHT were charged to a 500ml reactor (equipped with stirrer, lean air inlet, dropping funnel and condenser) and heated to 60 ℃. The reactor containing the heated mixture was then purged with oxygen-depleted air (consisting of nitrogen and oxygen in a 3: 1 flow ratio). Then, the specified amount of Acclaim 4200 polyol is loaded into the feed vessel along with the corresponding amount of DBTDL as specified under the row labeled "DBTDL (1)". After this time, the combination was slowly added dropwise to the reactor, which had been held at 60 ℃ for a feed time of 1 hour. In order to control the additional heating due to the ongoing exothermic reaction, the temperature was kept below 65 ℃ by a water cooling technique, wherein a water tank was applied to cool the outside of the reactor. The temperature of 60 ℃ was then maintained for a further 1 hour. Thereafter, a small sample was taken and the NCO content was measured by potentiometric titrators to ensure that the NCO content was within ± 0.2% of the theoretical isocyanate content value, which can be deduced from the amounts specified in table 2B for each oligomer. If it is determined that the content is not within the permissible range, the reaction is continued at 60 ℃ with subsequent additional measurements every 15 minutes until an acceptable NCO content value is reached.

In determining NCOWith the values present within the acceptable range, BHT (in the amounts specified in table 2B) was then loaded into the reactor. Next, HEA was loaded into the feed vessel along with the corresponding amount of DBTDL as specified in the row labeled "DBTDL (2)" from table 2B, and then slowly added dropwise over the course of 1-2 hours to the 60 ℃ reactor until the addition was complete. After this time, the reactor was heated to 85 ℃ and held at that temperature for an additional 2 hour period. Beginning at the end of the additional 2 hour period, the NCO content is again checked to ensure that NCO is present in an amount of less than 0.1% relative to the total weight of the composition. By verifying the NCO (located at about 2200-^-1At) the corresponding FT-IR spectral peak has completely disappeared to check this. Additional checks will then be continued every hour until the NCO content has dropped to the maximum allowable level. Finally, the resulting synthetic oligomer was slowly cooled and discharged for use in experiments described elsewhere herein.

Preliminary evaluation of various reactive diluent monomers

Several known reactive diluent monomers were screened for potential beneficial contributions to the formulations according to the present invention and are described in table 2C below. For each reactive diluent monomer, one or both of the relevant viscosity and dipole moment values at 25 ℃ are listed. The viscosity measurement was carried out according to the following method:

These experiments used an Anton Paar model Physica MCR501 instrument. The rheometer was equipped with a C-PTD200 temperature controller device consisting of a Peltier cooler/heater used with concentric cylinders and a dual gap measurement system. A so-called double gap DG26.7 system is used as the measurement geometry.

Sample preparation and Loading: each liquid monomer sample was loaded into a sample cartridge with a double gap geometry at room temperature using a disposable plastic pipette (7ml) and the geometry was held at an angle of about 45 degrees. This serves to prevent the inclusion of large bubbles in the double gap geometry. Next, approximately 6ml of the liquid to be investigated is loaded into a double gap geometry, thereby completingThe measuring cell is fully filled and the correctness of the geometric surface area value of the sample is ensured. This amount of material is needed to ensure that the blind riser (bob) of the double gap geometry is completely submerged in the liquid (i.e., the geometry is slightly overloaded when this amount of sample is used).

Atmosphere and shielding of the investigated sample: the measurement was performed in air. To minimize evaporation of the liquid monomer sample under study, the top surface of the liquid was covered inside the geometry with a top cap of a solvent trap system attached to the blind riser of the double gap geometry.

Measurement:next, a measurement protocol consisting of the following successive steps is followed:

1. the temperature was set to 25 ℃ for a duration of 5 minutes without shearing or data collection to bring the sample and geometry to temperature equilibrium.

2. A stable shear measurement was performed at 25 ℃ and a shear rate ramp curve was applied with increasing shear rate from 1s "1 to 1000 s" 1 and 3 data points per decade. No specific time setting is applied in order to collect individual data points. The value at 100s-1 was taken as the viscosity value at 25 ℃.

These values are reported below in table 2C below under the heading "viscosity at 25 ℃ (Pa · s)".

Meanwhile, the dipole moment value is a calculated boltzmann average dipole moment as described in known literature, e.g., Fast Monomers: fans influencing the incoming response of Acrylate Monomers in photosynthetic Acrylate Polymerization; macromolecules 2003, 36, 3681, 3873 (as amended on 3/4/2003) and/or US 6916855. Values are expressed in units of debye (D). Where indicated, the estimation is based on a relative comparison with the values of known monomers having similar structures.

TABLE 2C-dipole moments of the various monomers used

a: estimated by comparison with known values for isodecyl acrylate and 2-ethylhexyl acrylate.

b: estimated by comparison with published values for 2-hydroxyethyl acrylate.

c: estimated by comparison with published values for N-methylpyrrolidone.

d: the evaluation was made by comparison with known values for dimethylformamide and dimethylacetamide.

Preliminary evaluation of reactive oligomers

Next, a number of oligomers, each synthesized according to two different techniques (outside-in/"OI" or inside-out/"IO"), were evaluated according to the Size Exclusion Chromatography (SEC) method described below to see the effect of different diisocyanates (H12MDI, PDI, TMDI, HDI and IPDI) on the oligomer viscosity. The oligomers marked with an asterisk indicate oligomers that are not directly synthesized as described above, but they represent a inside-out synthesis of the same oligomers as specified elsewhere herein by a outside-in method (as indicated).

The values for number average molecular weight (Mn), weight average molecular weight (Mw), peak molecular weight (Mp), and Z average molecular weight (Mz) are reported in table 2D below. Two parameters derived from one or more of Mn, Mw, Mp and Mz are also reported. The first parameter is polydispersity, which is a representation of Mw/Mn, and the second parameter is a relatively high molecular weight ratio, which is represented by the following equation (9):

SEC was performed on a Waters APC (advanced polymer chromatography) device equipped with the following column set:

·Acquity APC XT2.5μm

·Acquity APC XT1.7μm

two detectors were used: refractive index detector (RI) and PDA (photodiode array detector). The software package used was Waters Empower 3. All readings were calibrated against polystyrene standards.

Meanwhile, typical operating conditions are as follows:

sample size: 10 μ l

Flow rate: 0.8 ml/min.

Eluent: THF containing 0.8% (v/v) acetic acid

Run time: for 10 min.

The column and detector were maintained at a temperature of about 40 ℃.

Calibration with polystyrene standards

The integration scheme is performed manually according to methods known in the art to which the invention is applicable. The baseline was plotted such that only the polyol-containing fraction (excluding the amount of HEA-isocyanate-HEA adduct) of each oligomer is reported in table 2D below.

Finally, the steady state viscosity at 25 ℃ of each oligomer was determined according to the following determination method under the heading "measurement of steady state viscosity at 25 ℃, 55 ℃ and 85 ℃ using the following changes:

the viscometer used is Brookfield DV-III (ULTRA). For oligomers with viscosity ranging from 450cP to 25000cP, a No. 40 spindle was used. For oligomers with a usable viscosity greater than 25,000cP (up to 800,000cP), a No. 52 spindle is used. The torque value of the viscometer is controlled to be about 45% to 50%.

The weight of the sample was kept at about 0.5 ml.

TABLE 2D-relative high molecular weight specific molecular weights of various oligomers are specified in units of kg/mol

Examples 1 to 50

Next, the mixture of oligomer, monomer(s) and photoinitiator was weighed on a 10-20g scale in an opaque polypropylene cup. Mixing was carried out in a so-called speed mixer (brand Hauschild type DAC 150FVZ) at 3000-. The temperature during mixing increased by up to 10 ℃. If the (solid) photoinitiator is not completely dissolved visually, the mixing procedure is repeated. The samples were stored in the same cup.

For examples 15 and 16, the filler was then added using an ultrasonic stirrer. For these examples, a base formulation consisting of oligomer, monomer component and photoinitiator was prepared as previously described. For the preparation of the mixtures using the fillers, a 15ml glass bead bottle was filled almost completely with the exactly measured quantityR972. Next, a weighed amount of base resin formulation is added in the amount required to obtain the desired weight ratio of Aerosil in the final mixture. The precision of the weighing needs to be adapted to obtain a precision of greater than or equal to ± 0.01% of the weight fraction of filler in the final formulation. By inserting an ultrasonic probe (by sonic) &Materials inc. standard 1/2 "solid state probe made of titanium alloy TI-6 Al-4V), the bottle with filler and resin was subjected to ultrasonic agitation for a total of 30 seconds, the ultrasonic probe operating at 40% of its capacity. This is done in three steps. After the first 15 seconds of ultrasonic mixing, the ultrasonic probe was removed several times and then reinserted into the mixture to obtain additional macroscopic mixing of the sample. Finally, ultrasonic agitation was applied for another 15 minutes. The mixing was performed at room temperature under atmospheric conditions.

These samples were tested according to the method described below to determine the steady state viscosity of each composition at 25 ℃, 55 ℃ and 85 ℃. These values are reported as η in tables 3A, 3B, 3C and 4, respectively₂₅、η₅₅And η₈₅. Values expressed as two decimal places rounded to, but less than 0.10 PaExcept for the value of the second; such values are expressed in three decimal places after rounding. The temperature sensitivity of each composition is also reported, expressed as the steady state viscosity ratio from 25 ℃ to 55 ℃ and also from 25 ℃ to 85 ℃. These values are reported in tables 3A, 3B, 3C and 4, respectivelyAnd andusing a value of eta not rounded₂₅、η₅₅And η₈₅The value is calculated and reported to the last two decimal places. Finally, the liquid glass transition temperature of each sample was also determined by using the calculation method described herein. Such values are reported rounded to one decimal place.

Measurement of steady-state viscosity at 25 deg.C, 55 deg.C and 85 deg.C

General description:a general description of the measurement of the steady-state shear viscosity of resins can be found in ISO 3219 "Plastics-Polymers/resins in liquid form or as emulsions or dispersions-viscosity measured using a rotational viscometer with a defined shear rate (Plastics-Polymers/resins in the liquid state or emulsions or dispersions-Determination of the viscosity using a rotational viscometer with defined shell rate)". To analyze the steady state shear viscosity of the uncured optical fiber coating formulation according to the invention, the rotational rheometer should be equipped with a measurement geometry to measure the viscosity at 10s at a temperature between at least 20 ℃ and 90 ℃^-1Is sufficiently sensitive to determine the viscosity at the deformation rate. Care should be taken to avoid evaporating the components of the sample under investigation during the experimental procedure to a level that would affect the measurement result beyond a typical experimental accuracy of +/-5%. Although not limiting, the inventionThe following preferred setup for performing such measurements is described herein below.

Equipment:these experiments used an Anton Paar model Physica MCR501 instrument. The rheometer was equipped with a C-PTD200 temperature controller device consisting of a Peltier cooler/heater used with concentric cylinders and a dual gap measurement system. A so-called double gap DG26.7 system is used as the measurement geometry.

Sample preparation and loading:the liquid was loaded into a sample cup with a double gap geometry at room temperature using a disposable plastic pipette (7ml) and the geometry was held at an angle of about 45 degrees. This serves to prevent the inclusion of large bubbles in the double gap geometry.

Next, about 6ml of the liquid to be investigated is loaded into the double gap geometry, thereby completely filling the measuring cell and ensuring the correctness of the values of the geometric surface area of the sample. This amount of material is needed to ensure that the blind riser (bob) of the double gap geometry is completely submerged in the liquid (i.e., the geometry is slightly overloaded when this amount of sample is used).

Atmospheric and masking of the samples studied:the measurement was performed in air. To minimize evaporation of components in the sample under study, the top surface of the liquid was covered inside the geometry with a cap of a solvent trap system attached to the blind riser of the double gap geometry.

Measurement:next, a measurement protocol consisting of the following sequential order was followed:

1. the temperature was set to 20 ℃ for a duration of 15 minutes without shearing or data collection to bring the sample and geometry to temperature equilibrium.

2. Using a temperature interval of 5 ℃ and 10s^-1A step temperature steady state shear test sequence from 20 ℃ to 90 ℃ was performed. After 10 minutes of equilibration to the next temperature without shearing, use 10s^-1The shear rate of (a) starts a steady state shear measurement, after which 15 data points are acquired using a measurement duration of 6 seconds per data point.The average of these data points is then taken as the viscosity value at the particular measurement temperature. This sequence was repeated until the measurement temperature reached 90 ℃. Finally, data points from these results were extracted for viscosity at 25 ℃, 55 ℃ and 85 ℃.

The following (optional) measurement sequence was also added to perform a consistency check on the viscosity data obtained from the step temperature measurement sequence. Such steps are specifically incorporated to check whether changes in the viscosity of the liquid, for example due to evaporation during measurement, can be ignored:

3. after completion of the step temperature sequence, the temperature was set to 85 ℃ for a duration of 10 minutes without shearing or data collection to achieve temperature equilibration of the sample and geometry.

4. Next, the shear rate was started for 10s^-1A steady state shear measurement was taken, after which 15 data points were acquired using a measurement duration of 6 seconds per data point.

5. The data points obtained were averaged and then verified whether they are consistent with the viscosity at 85 ℃ as determined by the step temperature steady state shear measurement previously performed within 10% accuracy.

6. Next, the temperature was set to 55 ℃ for a duration of 15 minutes without shearing or data collection to bring the sample and geometry to temperature equilibrium.

7. After that, 10s was used^-1The shear rate of (a) starts an additional steady state shear measurement and 15 data points are acquired using a measurement duration of 6 seconds each per data point. An average of the acquired data points is then established, wherein it is verified whether the value is consistent with the viscosity at 55 ℃ as determined by the step temperature steady state shear measurement previously performed within 10% accuracy.

8. In addition, the temperature was then set to 25 ℃ for a duration of 15 minutes without allowing any shearing or data collection to ensure temperature equilibration of the sample with the geometry.

9. Finally, use 10s^-1The shear rate of (a) initiates additional steady state shear measurements, after which each data point is usedA measurement duration of 6 seconds acquired 15 data points. These acquired data points are then averaged and checked to verify if they are consistent with the viscosity at 25 ℃ as determined by the step temperature steady state shear measurement previously performed within 10% accuracy.

The above procedure was applied to each of the examples, wherein the viscosity value at 25 ℃ was reported as η₂₅The viscosity number at 55 ℃ is reported as eta₅₅And the viscosity number at 85 ℃ is reported as eta₈₅. The results are described in tables 3A, 3B, 3C, and 4 below.

Temperature sensitivity of liquid resin viscosity (Tg, rheo)

The values reported under the "Tg, rheo" table are the results of curve fitting calculations, the results of applying one or more of expressions (1) to (8) of the Williams-Landel-Ferry equation to actual rheological data (the methods for obtaining which are explained above), reported in table 3A, table 3B, table 3C and table 4. Preferably, simplified equation (8) may be used:

wherein eta (T) is the viscosity of the composition at the temperature T, and eta₂₅Is the first viscosity.

As used above, η (T) represents the total viscosity data measured between 20 ℃ and 90 ℃, from which the viscosity at 25 ℃ (η) is derived₂₅) Used as a reference value. Next, a non-linear regression fit was applied to determine the values of Tg, rheo, which provided the best overall fit to the calculated WLF fit of the experimental data. This is done using a program solve plug-in (Solver add-in) at MicrosoftImplemented in a worksheet. The results for each example and comparative example are depicted in tables 3A, 3B, 3C, and 4 below.

Fig. 3 shows that a curve fit (example 24 is depicted) is performed to establish Tg, rheo values according to the foregoing procedure and equation. The data points represented by circles illustrate experimentally obtained values, while the fitting equation is represented by a dashed line. The data points plotted with crosses depict additional measurements at 85 ℃, 55 ℃ and 25 ℃ during cooling, which were determined as stability checks.

TABLE 4

Viscosity versus temperature sensitivity for comparative examples 1 to 6. Viscosity values are reported in pascal seconds (Pa · s). The ratio is unitless.

Film preparation of examples 40, 45, 47 and examples 51 to 53

Next, additional samples were prepared to evaluate several mechanical properties, which are understood to be related to the performance of the primary coating for optical fiber coating applications. To screen the ideal candidates for further testing, real-time dynamic mechanical analysis (RT-DMA) during curing was performed on each of the above examples 1-50. The RT-DMA method is known and described in P.A.M.STEeman et al, Macromolecules 2004, 37, pages 7001-7007. Three of several coatings exhibiting film modulus values indicative of suitable ranges for potential optical fiber primary coating applications (e.g., those having a shear modulus of about 0.1MPa to 0.3 MPa), i.e., the compositions of examples 40, 45, and 47, were selected as a basis for use in coating applications by kinetic actuation according to the method described below Dynamic Mechanical Analysis (DMA) was used for further mechanical property testing. To perform such evaluations, cured films were prepared from the compositions of examples 40, 45 and 47 according to the sample preparation methods described below. Furthermore, three additional samples (examples 51 to 53) were prepared having compositions similar to examples 40, 45 and 47, respectively, but with the addition of different amounts of another difunctional reactive diluent monomer (TPGDA). The complete composition of each example selected for further analysis is described in table 5 below. Results of mechanical property testing, including DMTA recorded value of tensile modulus E' 23, uniaxial tensile test recorded value of strain hardening parameter α, and strain energy release rate (G)₀) As shown in table 6 below.

TABLE 5

The amounts listed are in parts by weight.

Dynamic Mechanical Thermal Analysis (DMTA) for determining storage modulus at 23 deg.C

Tensile modulus was determined by dynamic mechanical analysis. The storage modulus at 23 ℃ of the primary coating of the invention (E' 23) is measured by DMTA under Tension according to Standard Test Method for Measuring the Dynamic Mechanical Properties of Plastics under Tension "Standard Test Method for Measuring the Dynamic Mechanical Properties of Plastics in Tension" ASTM D5026-95a "Standard Test Method for Measuring the Dynamic Mechanical Properties of Plastics under Tension". Temperature sweep measurements were performed under the following test conditions:

Test piece: rectangular strip

Length between the jaws: 25mm

Width: 1-2mm

Thickness: about 50-160 microns

The apparatus used: temperature gradient tests were performed on a DMTA machine from a TA instruments model RSA-G2. The machine was run at a frequency of 1Hz with an initial strain of 0.15%. The temperature cycle was started at-130 ℃ and heated to 225 ℃ at a ramp rate of 5 ℃ per minute. The following characteristics of automatic tension and automatic strain are applied:

automatic tension:

omicron static force tracking dynamic force

Initial static force: 1.0N

O static > dynamic force 25%

Automatic strain:

omicron maximum applied strain: 5 percent of

-minimum allowed force: 0.05N

Omicron maximum allowed force: 1.3N

Adjusting strain: (of the present strain) 20%

Determining the dimensions of a test piece: the thickness of the sample was measured with an MT 30B type electron Heidenhain thickness measuring device with a resolution of 1 micron. At the same time, the width was measured with a MITUTOYO microscope with a resolution of 1 μm.

In DMTA measurement as dynamic measurement, according to the following relation E ═ (E ═ E'²+E″²)^1/2The loss tangent (tan δ) and the following moduli were measured: storage modulus E', loss modulus E ", and dynamic modulus E. The storage modulus E 'at 23 ℃ in the DMTA curve is taken as the value of E' 23. Typically, the accuracy of these measurements is between 5-7%.

The E 'value (expressed as E' 23 and reported in MPa) at 23 ℃ for each sample tested was then recorded and reported in table 6 below.

Stress/strain curves from uniaxial tensile testing

The main data source for this test is the force-displacement curve, which is a "vulcanized or thermoplastic rubber" according to international standard ISO 37 (third edition 1994-05-15): determination of tensile stress-strain characteristics (Rubber, crushed or thermoplastic: Determination of tensile stress-strain properties)'. While using the primary coating of the invention, the following conditions were applied:

test piece: the dumbbell piece: and (3) type.

Length between the jaws: 30 mm.

Initial length l₀：9-12mm。

Thickness: about 120 and 160 microns.

Device: the tensile test was performed on a model ZWICK Z010 tensile machine. The force sensor employed was a 10N load cell, but a 50N load cell could be used instead if excessive environmental shock or other interference is expected. At the same time, the elongation was determined by a video extensometer (video extensometer) with a 16mm lens and a 200mm field of view and a resolution of 0.001 mm. The clamp used in this setup was a 8153 type screw clamp with a maximum force of 20N (ZWICK product No. 313348).

In terms of test speed, modulus measurements were made at 1mm/min between 0.3-3% strain and then at 50mm/min until failure.

The size of the dumbbell sample was then determined. The thickness of such samples was determined with the aid of an electronic Heidenhain thickness measuring device of the MT 30B type with a resolution of 1 micrometer. The width of the sample was created using stamping, with a width of 4mm according to ISO37 (type 3). The test was performed at a temperature of 23 + -2 deg.C and a relative humidity of 50 + -10%.

Five specimens were used for each test. The strain hardening parameter a (discussed below) is then determined from the curve that best represents the average characteristics of the 5 curves. A typical standard deviation of these measurements is 5% of the mean.

Strain energy release rate or tear strength (G)₀) Measurement of

Rubber was "vulcanized according to the international standard specification ISO 816 (second edition 1983-12-01) under the following specific conditions: determination of the tear Strength of Small test pieces (Delft test pieces) 'measurement of Strain energy Release Rate G (Rubber, gauged: Determination of tear Strength of Small test pieces (Delft test pieces)')₀：

Test piece: according to ISO 816

Length between the jaws: 30mm

Thickness (d): about 120 and 160 microns

Slit length (B): length of initial crack defined in ISO 816

Equipment: testing was performed on a digital stretcher from the ZWICK Z010 model

The type of clamp: 8153 type screw clamp with maximum force of 20N (Zwick product number 313348)

Force sensor: preferably 10N load cells, and a 50N load cell may be used instead in the event of excessive disturbances (e.g., environmental shocks)

Elongation: measured using machine displacements having a resolution of 0.001 mm/measured increment

Test speed: 0.1mm/min

Size of the test piece:

thickness (d): measured with an MT 30B type electronic Heidenhain thickness measuring device with a resolution of 1 micron.

Width (B): measured using a MITUTOYO microscope with a resolution of 1 micron.

Test temperature: 23. + -. 2 ℃ at a relative humidity of 50. + -. 10%.

Again, five samples were used. Reported G_oThe values are the average of these five samples. Typical standard deviations of these results are 15% of the mean.

Strain energy release rate G₀Is 1m per the above-mentioned test specimen of the cured primary coating initially containing small cracks equal to the slit length b as defined in ISO 816²The energy required for cracking. Then, G is calculated as follows₀：

Where F is the breaking force, B is the slit length, d is the thickness of the test piece, B is the width of the test piece, and E is the secant modulus at a test speed of 0.1mm/min, as calculated from the stresses at 0.05% and 2% elongation, with the test method described in "determination of the stress/strain curve from uniaxial tensile testing", where C defines the sample geometry as follows:

G for each test sample was then recorded₀Value (in J/m)²Reported in units) and reported in table 6 below.

Determination of the Mooney Curve

Uniaxial force-displacement curves were measured according to the procedure relating to Stress/Strain curves from Uniaxial Tensile tests (Stress/Stress Curve from a Uniaxial Tensile Test) as described elsewhere above. From this measurement, the engineering stress and the mooney stress were calculated according to formulas (12) to (14) given in the following description.

Relative mooney plots were obtained as follows. The main measurement is a force-displacement curve measured according to ISO 37 at a speed of 5mm/min, preferably 50mm/min, and more preferably 500 mm/min. At higher speeds, it is more certain that the effect of the material can be measured, particularly when the strain hardening properties are set only at higher strains. From this measurement, the engineering stress σ can be calculated according to equation (12)_E：

Where F is the force and A is the initial cross section of the sample. The strain λ is then calculated according to equation (13):

wherein l_oIs the initial length, and/is the actual length of the prismatic area of the sample tested.

Then, from this engineered stress, the mooney stress σ was calculated further according to the procedure described in Elastomers and Rubber Elasticity, j.e. mark and j.lal, 1982, ACS Symposium Series 193, American Chemical Society Washington DC _MThe calculation involves the following formula:

finally, σ can be plotted_MThe curves of 1/lambda are compared to construct a so-called Mooney plot.

In such a graph, the strain hardened material shows an increase in relative mooney stress at lower 1/λ values (i.e., higher elongation). In contrast, an ideal rubber material does not exhibit such an increase in relative mooney stress at lower 1/λ values, because the engineering stress of an ideal rubber material is given by the following formula:

wherein E is the tensile modulus. Mooney stress σ of ideal rubber materials_MIs E and remains equal to E as the strain λ is increased. The strain hardened material behaves as a spring that may have limited extension. It exhibits linear elastic behavior at small initial strains, but develops a limit on its ability to stretch as the strain increases further. In this regard, much higher stresses are required to further stretch the material and thereby allow the cavity to develop and grow. In the Mooney plot, this is seen by a rather steep increase in the relative Mooney stress with increasing strain λ. The amount of strain hardening is an important material property for developing a primary coating for a cavitation-resistant optical fiber. Later we describe a method for determining a parameter that quantifies this property in terms of the mooney curve.

In practice, rubbers tend to exhibit strain softening at low elongation (which is the case with strain hardened rubbers) and then harden at high elongation. Thus, mooney plots typically show the minimum in mooney curves at moderate strains. This has been described in the literature, for example in the articles by S.F. Edwards and Th.Vilgis (Polymer (1986), Vol.27, 4, p.483-492, FIGS. 4 and 5). The portion of the curve at elongation beyond the minimum of the Mooney curve (i.e., less than 1/λ at the minimum of the Mooney curve)_minOf 1/lambda) will be used to determine the so-called strain hardening parameter alpha.

Determination of Edwards-Vilgis Strain hardening parameter alpha (alpha)

Next, the Edwards-Vilgis strain hardening parameters of the material according to the invention were determined by fitting the measured stress-strain characteristics to the Edwards-Vilgis stress-strain relationship for the uniaxial deformation of the rubber. In their papers (S.F. Edwards and Th.Vilgis (Polymer (1986), Vol.27, 4, p.483-492, at equations 4.30 to 4.32), Edwards and Vilgis have introduced a slip chain model for the free energy of rubber deformation₁＝λ，λ₂＝λ₃1/√ λ) can be obtained by taking the derivative of the free energy with respect to deformation. To quantify the strain hardening behavior, we used equation 4.31 from Edwards et al on the contribution of the immobilized cross-links (assuming the number of cross-links N _cNon-zero) and by counting the number N of sliding chains_sSet to zero and ignore the contribution from the sliding chain of equation 4.30. This E-V stress-strain curve is then converted to a corresponding mooney curve following the procedure described elsewhere herein above. For less than 1/lambda_min(minimum value of Mooney Curve) 1/lambda value, parameter N_cAnd α can be determined from a least squares fit of an Edward-Vilgis uniaxial Mooney curve to a Mooney curve from experimental stress strain data. According to this part of the curve, only data points are considered where the mooney stress is greater than 1.01 times the minimum stress. Fig. 9 shows such a fit to embodiment 53 of the present invention. The alpha values for each test sample are depicted in table 6 below.

Sample preparation of cured films

As a substrate for preparing the film, a glass plate treated with fluorosilane was used in order to make the release of a free-standing film good for further analysis. The glass plate was treated by chemical vapor deposition with (heptadecafluoro-1, 1, 2, 2-tetrahydrodecyl) trimethoxysilane in a vacuum oven at 120 ℃ for about 16 hours. Typically, 0.5-1g was used for 20 glass plates (size 10em by 15 cm). Then by applying a 200 μm doctor blade to these channels A liquid layer was applied to the pre-treated glass plate to prepare a free-standing film. The coated glass plate was then passed 5 times under a UV rig (Fusion) equipped with a 395nm UV-LED source (Heraeus IRIS type X-II) under a nitrogen flow of 10.4m/min to obtain a cured film. The LED sources were configured for 20% power and 90% PWM (power modulation) settings, which resulted in 1.2W/cm²The strength of (2). The total corresponding light dose applied was 2.5J/cm². By Efsen UV&Calibrated EIT produced by EB technologyA II analyzer (S/N20298) measures dose and intensity values. The PowerPuck analyzer is configured to measure dose and intensity per square centimeter of surface area over a wavelength interval of 370-410nm (defined as the UVA2 range according to the manufacturer's specifications).

Next, the cured film was released from the glass plate by treating the film with Polyethylene (PE) powder and then slowly removing the film from the glass plate. It is believed that the PE powder on the surface of the free-standing film does not affect its properties. After preparation, samples were stored under ambient laboratory conditions (23 ± 2 ℃ at 50 ± 10% relative humidity) for up to five days.

TABLE 6 mechanical test results

Examples	E′23[MPa]	α[-]	G₀[J/m²]
				40	0.72	0.14	33.2
45	0.36	0.10	34.9
				47	0.42	0.09	28.5
51	0.80	0.18	34.9
				52	0.53	0.18	51.9
53	0.66	0.18	37.4

Discussion of results

As can be seen from the data in tables 3A, 3B, 3C and 4, compositions according to various aspects of the present invention exhibit reduced heat sensitivity, such as by the viscosity ratio (C And) Or alternatively via the liquid Tg (Tg, rheo) of the material.Although not all examples have photoinitiators or commercially known additives that are common in commercially available primary coating compositions for optical fibers, their properties here illustrate their suitability as at least one precursor composition for use in optical fiber coating applications, where an increased amount of thermal stress is imposed on the applied coating as photoinitiators and additives are not expected to significantly affect temperature sensitivity. Such increased thermal stress can be induced, for example, by increased line speed relative to commercial standard values, or by reducing or eliminating the amount of cooling (via helium flow or otherwise) fluid applied to the composition during the coating process.

The results are further graphically shown in fig. 4-7. Turning to fig. 4, the performance advantages of at least three compositions (examples 12, 13 and 14) according to aspects of the present invention, relative to three existing commercial optical fiber commercial coatings, are depicted when the viscosity of each composition is plotted as a function of temperature between 25 ℃ and 85 ℃. Examples 12-14 can be considered good candidates for use in optical fiber coating processes that cause increased thermal stress upon coating as evidenced by their relatively high measured viscosity values at elevated (latent operating) temperatures of 85 ℃. This is true despite the fact that examples 12 and 13 at least exhibit lower initial viscosities (i.e., at 25 ℃) than the commercial coatings represented by comparative examples 4 and 5.

Turning to fig. 5, a plot of viscosity versus temperature is shown, which is similar to the plot in fig. 3. In this figure, examples 14 and 19 are described as being superior to comparative examples 4 and 5 in their relatively reduced temperature sensitivity over the measurement range from 25 ℃ to 85 ℃. It is noteworthy that example 19 has approximately the same viscosity at 25 ℃ as comparative examples 4 and 5, but when it becomes heated it exhibits reduced viscosity change compared to those commercial coatings.

Figures 6 and 7 provide a depiction of the steady state shear viscosity of examples 1-24 on the x-axis (at 25 c in figure 6 and 85 c in figure 7) versus the viscosity ratio of each composition on the y-axis (whether between 25 c/55 c in figure 6 or between 25 c/85 c in figure 7). At the same time, fig. 8 depicts similar information regarding the viscosity ratio between 25 ℃ and 85 ℃ for examples 25 to 50. Higher performing, lower temperature sensitive compositions according to various aspects of the present invention are represented by the circular data points (or diamond data points in fig. 8), where lower performing, higher temperature sensitive compositions are represented by the data points in the form of "X" (i.e., comparative example). For each composition, a vertical line representing a viscosity ratio error bar is shown. As can be seen, a number of inventive embodiments are shown that span various ranges of viscosity ratios and initial viscosities.

Furthermore, the examples show that oligomers can be synthesized by alternative means to produce the desired compositional viscosity increase without any significant effect on the liquid glass transition temperature of the composition with which they are associated. This effect is most clearly demonstrated by comparing example 49 with example 26. The composition of example 49 was similar, but the synthesis changed from a outside-in (according to oligomer 7 used in example 26) to an inside-out process. The results depict that for a ten-fold increase in viscosity (15.10 pas versus 1.06 pas), the Tg, rheo increase is only 2.6 ℃.

At the same time, as shown in table 6, the inventors have found that the material according to the invention can also be tuned to have mechanical properties that are advantageous in applications as a primary coating for optical fibers. More specifically, the material according to the invention can be tuned to have a low tensile modulus (preferably less than 1.0MPa) desirable for good microbending properties, and to have high cavitation resistance (i.e., the susceptibility of the coating to cavity formation caused by internal or external stresses, as described in U.S. patent No. 7706659, which is hereby incorporated by reference). U.S. Pat. No. 7706659 teaches that the anti-cavitation coating has at least 20J/m ²Strain energy release rate of G₀(sometimes also referred to as tear strength) and exhibits strain hardening in the so-called stress-strain characteristic mooney curve.

Specifically, as can be seen from the results in Table 6, examples 40, 45 and 47 will be less than 1.0MPaHas a tensile modulus of more than 20J/m²Strain energy release rate of G₀And acceptable strain hardening values (alpha > 0.08). On this basis, such formulations are thus expected to also provide good cavitation resistance according to, for example, US 7706659. Examples 51 to 53 also show sufficiently low tensile modulus values with a significant improvement in strain hardening (. alpha. > 0.16) and G with minor formulation changes₀An increased combination. Accordingly, such embodiments are expected to produce optical fiber primary coatings with further cavitation resistance.

Additional exemplary embodiments

A first aspect of a first additional exemplary embodiment of the present invention is a coated optical fiber, comprising:

an optical fiber portion, said optical fiber portion further comprising

A glass core, and

a cladding layer in contact with and surrounding the glass core; and

a coating portion, said coating portion further comprising

A primary coating in contact with and surrounding the cladding; and

A secondary coating in contact with and surrounding the primary coating; wherein the primary coating is the cured product of a radiation curable composition comprising

A urethane acrylate oligomer that is the product of reactants comprising an isocyanate, a polyol, and an acrylate monomer;

a reactive diluent monomer; and

a free radical photoinitiator;

wherein the radiation curable composition has a first viscosity at 25 degrees Celsius (C.), a second viscosity at 55℃, and a third viscosity at 85℃, wherein the radiation curable composition is a liquid at each of the first, second, and third viscosities, and wherein the ratio of the first viscosity to the third viscosity is less than about 15, or less than about 14.4, or less than about 13.9, or less than about 13, or less than about 12, or less than about 11, or less than about 10, or less than about 9, or less than about 7.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to the preceding aspect, wherein the coated optical fiber has a mode field diameter of 8 μ ι η to 10 μ ι η at a wavelength of 1310nm or 9 μ ι η to 13 μ ι η at a wavelength of 1550 nm.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding two aspects, wherein the coated optical fiber is a single mode optical fiber and is configured to have a wavelength of between 20 μm²And 200 μm²The effective area therebetween.

Another aspect of the first additional exemplary embodiment is the coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the coated optical fiber is a multimode optical fiber and is configured to have a thickness of between 1500 μm²And 3500 μm²The effective area therebetween.

Another aspect of the first additional exemplary embodiment is the coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the ratio of the first viscosity to the third viscosity is less than 15, or less than 14.4, or less than 13.9, or less than 13, or less than 12, or less than 11, or less than 10, or less than 9, or less than 7.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the ratio of the first viscosity to the third viscosity is from about 5 to about 15, or from about 5 to about 14.4, or from about 5 to about 13.9, or from about 5 to about 13, or from about 5 to about 12, or from about 5 to about 11, or from about 5 to about 10, or from about 5 to about 9, or from about 5 to about 7, or from about 7 to about 15, or from about 7 to about 14.4, or from about 7 to about 13.9, or from about 7 to about 13, or from about 7 to about 12, or from about 7 to about 10, or from about 7 to about 9.

Another aspect of the first additional exemplary embodiment is the coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the ratio of the first viscosity to the third viscosity is 5 to 15, or 5 to 14.4, or 5 to 13, or 5 to 12, or 5 to 11, or 5 to 10, or 5 to 9, or 5 to 7, or 7 to 15, or 7 to 14.4, or 7 to 13.9, or 7 to 13, or 7 to 12, or 7 to 10, or 7 to 9.

Another aspect of the first additional exemplary embodiment is the coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the ratio of the first viscosity to the second viscosity is less than about 4.7, or less than about 4.6, or less than about 4.4, or less than about 4.2, or less than about 4.0, or less than about 3.5.

Another aspect of a first additional exemplary embodiment is a coated optical fiber according to the preceding aspect, wherein the ratio of the first viscosity to the second viscosity is from about 2 to about 4.7, or from about 3 to about 4.7, or from about 2 to about 4.6, or from about 3 to about 4.6, or from about 2 to about 4.4, or from about 3 to about 4.4, or from about 2 to about 4.2, or from about 3 to about 4.2, or from about 2 to about 4.0, or from about 3 to about 4.0, or from about 2 to about 3.5, or from about 3 to about 3.5.

Another aspect of a first additional exemplary embodiment is a coated optical fiber according to the preceding aspect, wherein the ratio of the first viscosity to the second viscosity is from 2 to 4.7, or from 3 to 4.7, or from 2 to 4.6, or from 3 to 4.6, or from 2 to 4.4, or from 3 to 4.4, or from 2 to 4.2, or from 3 to 4.2, or from 2 to 4.0, or from 3 to 4.0, or from 2 to 3.5, or from 3 to 3.5.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the second or third viscosity is greater than 0.01 pascal-seconds (Pa · s), or greater than 0.10Pa · s, or less than 1Pa · s, or between about 0.01Pa · s and about 1Pa · s, or from about 0.03Pa · s to about 0.8Pa · s, or from about 0.03Pa · s to about 0.5Pa · s, or from about 0.03Pa · s to about 0.4Pa · s, or from about 0.05Pa · s to about 1Pa · s, or from about 0.05Pa · s to about 0.5Pa · s, or from about 0.1Pa · s to about 1 · s, or from about 0.1 · s to about 0.8Pa · s.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to the preceding aspect, wherein the third viscosity is greater than 0.01 pascal-seconds (Pa · s), or greater than 0.10Pa · s, or less than 1Pa · s, or between about 0.01Pa · s to about 1Pa · s, or from about 0.03Pa · s to about 0.8Pa · s, or from about 0.03Pa · s to about 0.5Pa · s, or from about 0.03Pa · s to about 0.4Pa · s, or from about 0.05Pa · s to about 1Pa · s, or from about 0.05Pa · s to about 0.5Pa · s, or from about 0.1Pa · s to about 1Pa · s, or from about 0.1Pa · s to about 0.8 · s.

Another aspect of a first additional exemplary embodiment is a coated optical fiber according to the preceding aspect, wherein the first viscosity is between 0.1Pa · s and 20Pa · s, or from 0.5Pa · s to 15Pa · s, or from 1Pa · s to 10Pa · s, the second viscosity is between 0.03Pa · s and 6Pa · s, or from 0.05Pa · s to 5Pa · s, or from 0.1Pa · s to 3Pa · s, and the third viscosity is between 0.01Pa · s and 2Pa · s, or from 0.03Pa · s to 1.5Pa · s, or from 0.05Pa · s to 1Pa · s.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the primary coating has an in situ modulus of less than 2.0MPa, or less than 1.5MPa, or less than 1.4MPa, or less than 1.3MPa, or less than 1.2MPa, or less than 1.0MPa, or less than 0.8MPa, or less than 0.6MPa, or less than 0.5MPa, or less than 0.4MPa, or less than 0.3MPa to greater than 0.01MPa, or greater than 0.1MPa, or greater than 0.5 MPa.

Another aspect of the first additional exemplary embodiment is the coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the urethane acrylate oligomer is present at about 40 wt% to about 90 wt%, or about 50 wt% to about 70 wt%, or 45-90 wt%, or 45-70 wt% by weight relative to the total weight of the radiation curable composition.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to the preceding aspect, wherein the number average molecular weight of the polyol is 3000 to 10000, or 3000 to 8000, or 4000 to 10000, or 4000 to 8000, as measured by size exclusion chromatography using polystyrene standards in THF.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the polyol has a hydroxyl equivalent molecular weight of at least about 1500g/mol, or at least about 2000g/mol, or at least about 3000g/mol, or from 1500g/mol to 5000g/mol, or from 2000g/mol to 4500 g/mol.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the isocyanate comprises isophorone diisocyanate, 2, 4-trimethylhexamethylene diisocyanate, 2, 4, 4-trimethylhexamethylene diisocyanate and hexamethylene diisocyanate, 2, 4-toluene diisocyanate and 2, 6-toluene diisocyanate.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to the preceding aspect, wherein the isocyanate comprises a mixture of 2, 4-toluene-diisocyanate and 2, 6-toluene-diisocyanate.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to the preceding aspect, wherein the weight ratio of 2, 4-toluene-diisocyanate to 2, 6-toluene-diisocyanate is from 1: 1 to 100: 1, or from 30: 1 to 60: 1, or from 40: 1 to 50: 1.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the isocyanate consists essentially of isophorone diisocyanate, hexamethylene diisocyanate, or trimethyl-1, 6-diisocyanatohexane.

Another aspect of the first additional exemplary embodiment is the coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the acrylate monomer comprises methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-phenoxyethyl acrylate, 2-hydroxyethyl acrylate, lauryl acrylate, or isobornyl acrylate.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to the preceding aspect, wherein the urethane acrylate oligomer consists of one or more block copolymers.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding two aspects, wherein the block copolymer comprises a mono-block copolymer, a di-block copolymer, or a tri-block copolymer.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to the preceding aspect, wherein the urethane acrylate oligomer consists essentially of one or more block copolymers, wherein the one or more block copolymers comprise a mono-block, di-block, or tri-block structure.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the four preceding aspects of the first additional exemplary embodiment, wherein the block copolymer comprises polyether blocks.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the five preceding aspects of the first additional exemplary embodiment, wherein the urethane acrylate oligomer comprises an average of 0.9 to 3.5 polyether blocks, or between 0.9 and 1.5 polyether blocks, or between 1.5 and 2.5 polyether blocks, or between 2.5 and 3.5 polyether blocks.

Another aspect of the first additional exemplary embodiment is the coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the catalyst is present at 0.001 wt% to 1 wt%, or 0.01 wt% to 1 wt%, or 0.05 wt% to 1 wt%, or 0.001 wt% to 0.1 wt%, or 0.01 wt% to 0.1 wt%, or 0.05 wt% to 0.1 wt% relative to the amount of the entire radiation curable composition.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to the preceding aspect, wherein the butylated hydroxytoluene is food grade.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the inhibitor is present in an amount of 0.001 wt% to 1 wt%, or 0.01 wt% to 1 wt%, or 0.05 wt% to 1 wt%, or 0.001 wt% to 0.1 wt%, or 0.01 wt% to 0.1 wt%, or 0.05 wt% to 0.1 wt%, relative to the amount of the entire radiation curable composition.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the isocyanate is present at 1 to 20 wt.%, or 1 to 15 wt.%, or 1 to 10 wt.%, or 1 to 8 wt.%, or 1 to 6 wt.%, or 2 to 20 wt.%, or 2 to 15 wt.%, or 2 to 10 wt.%, or 2 to 8 wt.%, or 2 to 6 wt.%, or 3.6 to 20 wt.%, or 3.6 to 15 wt.%, or 3.6 to 10 wt.%, or 3.6 to 8 wt.%, or 3.6 to 6 wt.%, by weight relative to the total weight of the urethane acrylate oligomer.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the polyol is present at 80 to 99 wt.%, or 80 to 97 wt.%, or 80 to 96 wt.%, or 80 to 95.36 wt.%, or 85 to 99 wt.%, or 85 to 97 wt.%, or 85 to 96 wt.%, or 85 to 95.36 wt.%, or 91.22 to 99 wt.%, or 91.22 to 97 wt.%, or 91.22 to 96 wt.%, or 91.22 to 95.36 wt.%, by weight, relative to the total weight of the urethane acrylate oligomer.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the acrylate monomer is present at 0.3 wt% to 15 wt%, or 0.3 wt% to 10 wt%, or 0.3 wt% to 5 wt%, or 0.3 wt% to 3 wt%, or 0.3 wt% to 2.72 wt%, or 0.75 wt% to 15 wt%, or 0.75 wt% to 10 wt%, or 0.75 wt% to 5 wt%, or 0.75 wt% to 3 wt%, or 0.75 wt% to 2.72 wt%, or 1 wt% to 15 wt%, or 1 wt% to 10 wt%, or 1 wt% to 5 wt%, or 1 wt% to 3 wt%, or 1 wt% to 2.72 wt% by weight relative to the total weight of the urethane acrylate oligomer.

Another aspect of the first additional exemplary embodiment is the coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the molar ratio of the polyol to the acrylate monomer is from 1: 1 to 5: 1, or from 1: 1 to 4: 1, or from 1: 1 to 3: 1.

Another aspect of the first additional exemplary embodiment is the coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the molar ratio of the isocyanate to the acrylate monomer is from 1: 1 to 5: 1, or from 1: 1 to 4: 1, or from 1: 1 to 3: 1.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the number average molecular weight of the urethane acrylate oligomer is greater than about 8,000g/mol, or greater than about 10,000g/mol, or greater than about 15,000g/mol, or greater than 20,000g/mol, or greater than 25,000 g/mol.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the urethane acrylate oligomer has a number average molecular weight of about 8,000g/mol to about 30,000g/mol, or about 8,000g/mol to about 25,000g/mol, or about 8,000g/mol to about 20,000g/mol, or about 10,000g/mol to about 30,000g/mol, or about 10,000g/mol to about 25,000g/mol, or about 10,000g/mol to about 20,000g/mol, or about 15,000g/mol to about 30,000g/mol, or about 15,000g/mol to about 25,000g/mol, or about 15,000g/mol to about 20,000 g/mol.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the reactive diluent monomer comprises an alkyl acrylate having an alkyl chain comprising at least one carbon atom, or at least 2 carbon atoms, or at least 8 carbon atoms; or C₈-C₂₄Or C₈-C₁₆An alkyl chain.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to the previous embodiment, wherein the alkyl acrylate comprises isodecyl acrylate.

Another aspect of the first additional exemplary embodiment is the coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the reactive diluent monomer comprises methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, or isobornyl acrylate.

Another aspect of the first additional exemplary embodiment is the coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the reactive diluent monomer comprises ethyl hexyl acrylate, phenoxyethyl acrylate, N-vinyl caprolactam, 2-ethyl hexyl acrylate, or 2-phenoxyethyl acrylate.

Another aspect of the first additional exemplary embodiment is the coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the reactive diluent monomer consists of 2-ethylhexyl acrylate, 2-phenoxyethyl acrylate, or N-vinyl caprolactam.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, further comprising a second reactive diluent monomer.

Another aspect of the first additional exemplary embodiment is the coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the second reactive diluent monomer comprises ethyl hexyl acrylate, phenoxyethyl acrylate, or N-vinyl caprolactam.

Another aspect of the first additional exemplary embodiment is the coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the second reactive diluent monomer comprises 2-ethylhexyl acrylate, 2-phenoxyethyl acrylate, or N-vinyl caprolactam.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the reactive diluent monomer is present at least about 20 wt.%, or about 20 wt.% to about 60 wt.%, or about 30 wt.% to about 50 wt.% by weight relative to the weight of the entire coated optical fiber.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the reactive diluent monomer and the second reactive diluent monomer are present at least about 20 wt.%, or about 20 wt.% to about 60 wt.%, or about 30 wt.% to about 50 wt.% by weight relative to the weight of the entire coated optical fiber.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the reactive diluent monomer is present in a ratio of 1: 1 to 4: 1, or about 1: 1 to about 2: 1, by weight, relative to the second reactive diluent monomer.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the photoinitiator comprises a benzophenone, a benzoylphosphine oxide, an ethoxyphosphine oxide or an alkoxyphosphine oxide, or a 1-hydroxyphenylketone compound.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the photoinitiator comprises 4-methylbenzophenone, 2, 4, 6-trimethylbenzophenone, dimethoxybenzophenone, 1-hydroxycyclohexyl phenyl ketone, phenyl (1-hydroxyisopropyl) ketone, 2-hydroxy-1- [4- (2-hydroxyethoxy) phenyl ] -2-methyl-1-propanone and 4-isopropylphenyl (1-hydroxyisopropyl) ketone, benzildimethyl ketal, oligo- [ 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl ] propanone ]; 2, 4, 6-trimethylbenzoyldiphenylphosphine oxide, 2, 4, 6-trimethylbenzoylphenyl, bis (2, 4, 6-trimethylbenzoyl) -phenylphosphine oxide, 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinopropanone-1, 2-benzyl-2- (dimethylamino) -1- [4- (4-morpholinyl) phenyl ] -1-butanone, 2-dimethylamino-2- (4-methyl-benzyl) -1- (4-morpholin-4-yl-phenyl) -butan-1-one, 4-benzoyl-4' -methyldiphenylsulfide, 4, 4 '-bis (diethylamino) benzophenone and 4, 4' -bis (N, N-dimethylamino) benzophenone (meldonone), and mixtures thereof.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the photoinitiator is present in an amount of at least 0.1 wt%, or about 0.1-5 wt%, or 0.1-3 wt%, or about 0.1 wt% to about 2 wt%, or about 0.5 wt% to about 5 wt%, or about 0.5 wt% to about 3 wt%, or about 0.5 wt% to about 2 wt%, or about 0.5 wt% to about 1.5 wt%, or about 0.9 wt% to about 5 wt%, or about 0.9 wt% to about 3 wt%, or about 0.9 wt% to about 2 wt%, or about 0.9 wt% to about 1.5 wt%, relative to the weight of the entire composition.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to the preceding aspect, wherein the radiation curable composition further comprises trimethylpropane tris (3-mercaptopropionate).

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the adhesion promoter is present at 0.001 wt% to 5 wt%, or 0.01 wt% to 5 wt%, or 0.1 wt% to 5 wt%, or 0.5 wt% to 5 wt%, or 0.001 wt% to 3 wt%, or 0.01 wt% to 3 wt%, or 0.1 wt% to 3 wt%, or 0.5 wt% to 3 wt%, or 0.001 wt% to 1 wt%, or 0.01 wt% to 1 wt%, or 0.1 wt% to 1 wt%, or 0.5 wt% to 1 wt%, by weight relative to the weight of the entire radiation curable composition.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein the radiation curable composition has a liquid glass transition temperature (Tg, rheo), wherein the Tg, rheo, of the radiation curable composition is less than-81.5 ℃, or is from-120 ℃ to-80 ℃, or from-115 ℃ to-80 ℃, or from-110 ℃ to-80 ℃, or from-100 ℃ to-80 ℃, or from-120 ℃ to-82 ℃, or from-115 ℃ to-82 ℃, or from-110 ℃ to-82 ℃, or from-100 ℃ to-82 ℃, or from-120 ℃ to-85 ℃, or from-115 ℃ to-85 ℃, or from-110 ℃ to-85 ℃, ° 120 ℃ to-85 ℃, ° c, Or from-100 ℃ to-85 ℃, or from-120 ℃ to-90 ℃, or from-115 ℃ to-90 ℃, or from-110 ℃ to-90 ℃, or from-100 ℃ to-90 ℃; or from-120 ℃ to-97 ℃, or from-113 ℃ to-97 ℃.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to any of the preceding aspects of the first additional exemplary embodiment, wherein Tg, rheo is determined by fitting equation (8) to data of experimental viscosity versus temperature for the radiation curable composition:

Wherein eta (T) is the viscosity of the composition at the temperature T, and eta₂₅Is the first viscosity.

A first aspect of a second additional exemplary embodiment of the present invention is a radiation curable composition for coating an optical fiber, the radiation curable composition comprising:

a reactive oligomer comprising at least one polymerizable group and a backbone derived from a diol comprising polypropylene glycol;

a reactive diluent monomer; and

one or more photoinitiators;

wherein the radiation curable composition has a liquid glass transition temperature (Tg, rheo), a first viscosity at 25 degrees celsius (° c), a second viscosity at 55 ℃, and a third viscosity at 85 ℃;

wherein at least one of the following conditions is satisfied:

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to the previous aspect of the second additional exemplary embodiment, wherein Tg, rheo is determined by fitting equation (8) to data of experimental viscosity versus temperature for the radiation curable composition:

wherein eta (T) is the viscosity of the composition at the temperature T, and eta₂₅Is the first viscosity.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the reactive oligomer comprises a number average of 0.9 to 2.1 polymerizable groups, or 0.9 to 1.1 polymerizable groups, or 0.9 to 3.1 polymerizable groups, or 1.9 to 2.1 polymerizable groups, or 1.5 to 2.5 polymerizable groups.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the acrylate group is derived from methyl acrylate, phenoxyethyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, or isobornyl acrylate.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the reactive oligomer comprises a urethane acrylate oligomer, wherein the urethane acrylate oligomer is a reaction product of an isocyanate, an acrylate, and a polypropylene glycol.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the isocyanate comprises isophorone diisocyanate, hexane diisocyanate, toluene diisocyanate, 2, 4-trimethylhexane diisocyanate, 2, 4, 4-trimethylhexane diisocyanate, pentane diisocyanate, or 4, 4-methylenebis (cyclohexyl isocyanate).

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the weight ratio of the 2, 4-toluene-diisocyanate to the 2, 6-toluene-diisocyanate is from 1: 1 to 100: 1, or from 30: 1 to 60: 1, or from 40: 1 to 50: 1.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the urethane acrylate oligomer consists of one or more block copolymers, wherein the one or more block copolymers comprise a mono-block, di-block, or tri-block structure.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the urethane acrylate oligomer consists essentially of one or more block copolymers, wherein the one or more block copolymers comprise a mono-block, di-block, or tri-block structure.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the reactive oligomer comprises a reaction product of a polypropylene glycol having a number average molecular weight of 3,000 to 10,000, or 3,000 to 8,000, or 4,000 to 10,000, or 4,000 to 8,000, as measured by size exclusion chromatography using polystyrene standards in THF.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the polypropylene glycol has a hydroxyl equivalent weight of at least about 2000g/mol, or at least about 3000g/mol, or from 1500g/mol to 5000g/mol, or from 2000g/mol to 4500 g/mol.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the catalyst is present in an amount of 0.001 wt% to 1 wt%, or 0.01 wt% to 1 wt%, or 0.05 wt% to 1 wt%, or 0.001 wt% to 0.1 wt%, or 0.01 wt% to 0.1 wt%, or 0.05 wt% to 0.1 wt%, relative to the amount of the radiation curable composition as a whole.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the inhibitor is present in an amount of 0.001 wt% to 1 wt%, or 0.01 wt% to 1 wt%, or 0.05 wt% to 1 wt%, or 0.001 wt% to 0.1 wt%, or 0.01 wt% to 0.1 wt%, or 0.05 wt% to 0.1 wt%, relative to the amount of the entire radiation curable composition.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the isocyanate is present at 1 to 20 wt.%, or 1 to 15 wt.%, or 1 to 10 wt.%, or 1 to 8 wt.%, or 1 to 6 wt.%, or 2 to 20 wt.%, or 2 to 15 wt.%, or 2 to 10 wt.%, or 2 to 8 wt.%, or 2 to 6 wt.%, or 3.6 to 20 wt.%, or 3.6 to 15 wt.%, or 3.6 to 10 wt.%, or 3.6 to 8 wt.%, or 3.6 to 6 wt.%, by weight relative to the total weight of the reactive oligomer.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the polypropylene glycol is present at 80 to 99 wt%, or 80 to 97 wt%, or 80 to 96 wt%, or 80 to 95.36 wt%, or 85 to 99 wt%, or 85 to 97 wt%, or 85 to 96 wt%, or 85 to 95.36 wt%, or 91.22 to 99 wt%, or 91.22 to 97 wt%, or 91.22 to 96 wt%, or 91.22 to 95.36 wt% by weight, relative to the total weight of the reactive oligomer.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the acrylate monomer is present at 0.3 wt% to 15 wt%, or 0.3 wt% to 10 wt%, or 0.3 wt% to 5 wt%, or 0.3 wt% to 3 wt%, or 0.3 wt% to 2.72 wt%, or 0.75 wt% to 15 wt%, or 0.75 wt% to 10 wt%, or 0.75 wt% to 5 wt%, or 0.75 wt% to 3 wt%, or 0.75 wt% to 2.72 wt%, or 1 wt% to 15 wt%, or 1 wt% to 10 wt%, or 1 wt% to 5 wt%, or 1 wt% to 3 wt%, or 1 wt% to 2.72 wt% by weight relative to the total weight of the reactive oligomer.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the reactive oligomer has a number average molecular weight of greater than about 8,000g/mol, or greater than about 10,000g/mol, or greater than about 15,000g/mol, or greater than 20,000g/mol, or greater than 25,000 g/mol.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the reactive oligomer has a number average molecular weight of about 8,000g/mol to about 30,000g/mol, or about 8,000g/mol to about 25,000g/mol, or about 8,000g/mol to about 20,000g/mol, or about 10,000g/mol to about 30,000g/mol, or about 10,000g/mol to about 25,000g/mol, or about 10,000g/mol to about 20,000g/mol, or about 15,000g/mol to about 30,000g/mol, or about 15,000g/mol to about 25,000g/mol, or about 15,000g/mol to about 20,000 g/mol.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the number average molecular weight of the urethane acrylate oligomer is greater than about 8,000g/mol, or greater than about 10,000g/mol, or greater than about 15,000g/mol, or greater than 20,000g/mol, or greater than 25,000 g/mol.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the number average molecular weight of the urethane acrylate oligomer is from about 8,000g/mol to about 30,000g/mol, or from about 8,000g/mol to about 25,000g/mol, or from about 8,000g/mol to about 20,000g/mol, or from about 10,000g/mol to about 30,000g/mol, or from about 10,000g/mol to about 25,000g/mol, or from about 10,000g/mol to about 20,000g/mol, or from about 15,000g/mol to about 30,000g/mol, or from about 15,000g/mol to about 25,000g/mol, or from about 15,000g/mol to about 20,000 g/mol.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the reactive oligomer is present at least about 40 wt.%, or about 50 wt.% to about 70 wt.%, by weight relative to the weight of the entire radiation curable composition.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the reactive diluent monomer comprises from 0.9 to 2.1 polymerizable groups, or from 0.9 to 1.1 polymerizable groups, or from 0.9 to 3.1 polymerizable groups, or from 1.9 to 2.1 polymerizable groups, or from 0.5 to 1.5 polymerizable groups, by number average.

Another aspect of the second additional exemplary embodiment is the coated optical fiber according to any of the preceding aspects of the second additional exemplary embodiment, wherein the reactive diluent monomer comprises an alkyl acrylate having an alkyl chain comprising at least 8 carbon atoms, or C₈-C₂₄Alkyl chains or C₈-C₁₆An alkyl chain.

Another aspect of the first additional exemplary embodiment is a coated optical fiber according to the previous embodiment, wherein the alkyl acrylate comprises isodecyl acrylate.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the reactive diluent monomer comprises methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, isobornyl acrylate, lauryl acrylate, diethylene glycol ethylhexyl acrylate (DEGEHA), phenoxyethyl acrylate, or N-vinyl caprolactam.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the reactive diluent monomer consists essentially of ethylhexyl acrylate, phenoxyethyl acrylate, or N-vinyl caprolactam.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the reactive diluent monomer consists essentially of 2-ethylhexyl acrylate, 2-phenoxyethyl acrylate, or N-vinyl caprolactam.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the composition comprises a reactive diluent monomer having a calculated average dipole moment of greater than 2.2 debye, or greater than 2.3D, or greater than 2.35D, or greater than 2.5D, or from 2.2D to 4.2D, or from 2.3D to 4.1D, or from 2.35D to 4.0D, or from 2.35D to 3.7D, or from 2.35D to 3.0D, or from 2.4D to 4.1D, or from 2.4D to 4.0D, or from 2.4D to 3.7D, or from 2.4D to 3.0D.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the total calculated boltzmann average dipole moment of all reactive diluent monomers present in the composition is greater than 2.2 debye, or greater than 2.3D, or greater than 2.35D, or greater than 2.5D, or is from 2.2D to 4.2D, or from 2.3D to 4.1D, or from 2.35D to 4.0D, or from 2.35D to 3.7D, or from 2.35D to 3.0D, or from 2.4D to 4.1D, or from 2.4D to 4.0D, or from 2.4D to 3.7D, or from 2.4D to 3.0D.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the second reactive diluent monomer comprises 2-ethylhexyl acrylate, 2-phenoxyethyl acrylate, or N-vinyl caprolactam.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the reactive diluent monomer comprises ethyl hexyl acrylate and phenoxyethyl acrylate, or ethyl hexyl acrylate and N-vinyl caprolactam.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the reactive diluent monomer is present at a weight of at least about 20 wt%, or from about 20 wt% to about 60 wt%, or from about 30 wt% to about 50 wt%, relative to the weight of the entire radiation curable composition.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the photoinitiator comprises 4-methylbenzophenone, 2, 4, 6-trimethylbenzophenone, dimethoxybenzophenone, 1-hydroxycyclohexyl phenyl ketone, phenyl (1-hydroxyisopropyl) ketone, 2-hydroxy-1- [4- (2-hydroxyethoxy) phenyl ] -2-methyl-1-propanone and 4-isopropylphenyl (1-hydroxyisopropyl) ketone, benzildimethyl ketal, oligo- [ 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl ] propanone ]; 2, 4, 6-trimethylbenzoyldiphenylphosphine oxide, 2, 4, 6-trimethylbenzoylphenyl, bis (2, 4, 6-trimethylbenzoyl) -phenylphosphine oxide, 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinopropanone-1, 2-benzyl-2- (dimethylamino) -1- [4- (4-morpholinyl) phenyl ] -1-butanone, 2-dimethylamino-2- (4-methyl-benzyl) -1- (4-morpholin-4-yl-phenyl) -butan-1-one, 4-benzoyl-4' -methyldiphenylsulfide, 4, 4 '-bis (diethylamino) benzophenone and 4, 4' -bis (N, N-dimethylamino) benzophenone (meldonone), and mixtures thereof.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the photoinitiator is present in an amount of at least 0.1 wt%, or about 0.1-5 wt%, or 0.1-3 wt%, or about 0.1 wt% to about 2 wt%, or about 0.5 wt% to about 5 wt%, or about 0.5 wt% to about 3 wt%, or about 0.5 wt% to about 2 wt%, or about 0.5 wt% to about 1.5 wt%, or about 0.9 wt% to about 5 wt%, or about 0.9 wt% to about 3 wt%, or about 0.9 wt% to about 2 wt%, or about 0.9 wt% to about 1.5 wt%, relative to the weight of the entire composition.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the radiation curable composition is a liquid at each of the first, second, and third viscosities, and wherein the ratio of the first viscosity to the third viscosity is less than about 15, or less than about 14.4, or less than about 13, or less than about 12, or less than about 11, or less than about 10, or less than about 9, or less than about 7, or wherein the ratio of the first viscosity to the third viscosity is less than 15, or less than 14, or less than 13, or less than 12, or less than 11, or less than 10, or less than 9, or less than 7.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to the previous aspect of the second additional exemplary embodiment, wherein the ratio of the first viscosity to the third viscosity is from about 5 to about 15, or from about 5 to about 14.4, or from about 5 to about 13.9, or from about 5 to about 13, or from about 5 to about 12, or from about 5 to about 11, or from about 5 to about 10, or from about 5 to about 9, or from about 5 to about 7, or from about 7 to about 15, or from about 7 to about 14.4, or from about 7 to about 13.9, or from about 7 to about 13, or from about 7 to about 12, or from about 7 to about 11, or from about 7 to about 10, or from about 7 to about 9.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding two aspects of the second additional exemplary embodiment, wherein the ratio of the first viscosity to the third viscosity is 5 to 15, or 5 to 14.4, or 5 to 13, or 5 to 12, or 5 to 11, or 5 to 10, or 5 to 9, or 5 to 7, or 7 to 15, or 7 to 14.4, or 7 to 13.9, or 7 to 13, or 7 to 12, or 7 to 11, or 7 to 10, or 7 to 9.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding three aspects of the second additional exemplary embodiment, wherein the ratio of the first viscosity to the second viscosity is less than about 4.7, or less than 4.6, or less than about 4.4, or less than about 4.2, or less than about 4.0, or less than about 3.5, or wherein the ratio of the first viscosity to the second viscosity is less than 4.7, or less than 4.6, or less than 4.4, or less than 4.2, or less than 4.0, or less than 3.5.

Another aspect of a second additional exemplary embodiment is the radiation curable composition according to the previous aspect of the second additional exemplary embodiment, wherein the ratio of the first viscosity to the second viscosity is from about 2 to about 4.7, or from about 3 to about 4.7, or from about 2 to about 4.6, or from about 3 to about 4.6, or from about 2 to about 4.4, or from about 3 to about 4.4, or from about 2 to about 4.2, or from about 3 to about 4.2, or from about 2 to about 4.0, or from about 3 to about 4.0, or from about 2 to about 3.5, or from about 3 to about 3.5.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the ratio of the first viscosity to the second viscosity is from 2 to 4.7, or from 3 to 4.7, or from 2 to 4.6, or from 3 to 4.6, or from 2 to 4.4, or from 3 to 4.4, or from 2 to 4.2, or from 3 to 4.2, or from 2 to 4.0, or from 3 to 4.0, or from 2 to 3.5, or from 3 to 3.5.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the second or third viscosity is greater than 0.01 pascal-seconds (Pa · s), or greater than 0.10Pa · s, or less than 1Pa · s, or between about 0.01Pa · s and about 1Pa · s, or from about 0.03Pa · s to about 0.8Pa · s, or from about 0.03Pa · s to about 0.5Pa · s, or from about 0.03Pa · s to about 0.4Pa · s, or from about 0.05Pa · s to about 1Pa · s, or from about 0.05Pa · s to about 0.5Pa · s, or from about 0.1Pa · s to about 1 · s, or from about 0.1Pa · s to about 0.8Pa · s.

Another aspect of the second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the third viscosity is greater than 0.01 pascal-seconds (Pa · s), or greater than 0.10Pa · s, or less than 2Pa · s, or less than 1Pa · s, or between about 0.01Pa · s and about 1Pa · s, or from about 0.03Pa · s to about 0.8Pa · s, or from about 0.03Pa · s to about 0.5Pa · s, or from about 0.03Pa · s to about 0.4Pa · s, or from about 0.05Pa · s to about 1Pa · s, or from about 0.05Pa · s to about 0.5Pa · s, or from about 0.1Pa · s to about 1 · s, or from about 0.1 · s to about 0.8Pa · s.

Another aspect of a second additional exemplary embodiment is the radiation curable composition according to any of the preceding aspects of the second additional exemplary embodiment, wherein the first viscosity is between 0.1Pa · s and 20Pa · s, or from 0.5Pa · s to 15Pa · s, or from 1Pa · s to 10Pa · s, the second viscosity is between 0.03Pa · s and 6Pa · s, or from 0.05Pa · s to 5Pa · s, or from 0.1Pa · s to 3Pa · s, and the third viscosity is between 0.01Pa · s and 2Pa · s, or from 0.03Pa · s to 1.5Pa · s, or from 0.05Pa · s to 1Pa · s.

A third additional exemplary embodiment of the present invention is a coated optical fiber comprising a primary coating, wherein the primary coating is a cured product of the radiation curable composition according to any of the aspects of the second additional exemplary embodiment.

A first aspect of a fourth additional exemplary embodiment of the invention is a method for manufacturing a coated optical fiber, the method comprising the steps of:

drawing a glass optical fiber by a drawing tower;

applying a primary coating composition onto a surface of the glass optical fiber;

optionally, applying a dose of ultraviolet light sufficient to at least partially cure the primary coating composition;

applying a secondary coating composition to the primary coating composition;

exposing a primary coating composition and a secondary coating composition to at least one radiation source capable of emitting ultraviolet radiation to affect curing of the primary coating composition and the secondary coating composition to form a cured primary coating on a surface of the optical fiber, and a cured secondary coating on a surface of the cured primary coating;

wherein the primary coating composition comprises a reactive oligomer comprising at least one polymerizable group and a backbone derived from a glycol comprising polypropylene glycol;

A reactive diluent monomer; and

one or more photoinitiators;

wherein the radiation curable composition has a Tg, rheo of less than-81.5 ℃, or from-120 ℃ to-80 ℃, or from-115 ℃ to-80 ℃, or from-110 ℃ to-80 ℃, or from-100 ℃ to-80 ℃, or from-120 ℃ to-82 ℃, or from-115 ℃ to-82 ℃, or from-110 ℃ to-82 ℃, or from-100 ℃ to-82 ℃, or from-120 ℃ to-90 ℃, or from-115 ℃ to-90 ℃, or from-110 ℃ to-90 ℃, or from-100 ℃ to-90 ℃, or from-120 ℃ to-97 ℃, or from-113 ℃ to-97 ℃; or

Wherein the ratio of the first viscosity to the third viscosity is less than about 15, or less than about 14.4, or less than about 13.9, or less than about 13, or less than about 9, or less than about 7.

Another aspect of a fourth additional exemplary embodiment is the method according to the previous aspect, wherein the Tg, rheo is determined by fitting equation (8) to experimental viscosity versus temperature data for the radiation curable composition:

Wherein eta (T) is a combination ofViscosity at temperature T, and η₂₅Is the first viscosity.

Another aspect of a fourth additional exemplary embodiment is the method according to any of the preceding aspects, wherein the radiation curable composition is a liquid at the first, second, and third viscosities, and wherein the third viscosity is greater than 0.01 pascal-seconds (Pa-s), or greater than 0.10 Pa-s, or less than 1 Pa-s, or between about 0.01 Pa-s and about 1 Pa-s, or from about 0.03 Pa-s to about 0.8 Pa-s, or from about 0.03 Pa-s to about 0.5 Pa-s, or from about 0.03 Pa-s to about 0.4 Pa-s, or from about 0.05 Pa-s to about 1 Pa-s, or from about 0.05 Pa-s to about 0.5 Pa-s, or from about 0.1-s to about 1-s, or from about 0.05 Pa-s to about 0.8 Pa-s.

Another aspect of a fourth additional exemplary embodiment is a method according to any of the preceding two aspects, wherein the ratio of the first viscosity to the third viscosity is from about 5 to about 15, or from about 5 to about 14.4, or from about 5 to about 13.9, or from about 5 to about 13, or from about 5 to about 9, or from about 5 to about 7, or from about 7 to about 15, or from about 7 to about 14.4, or from about 7 to about 13.9, or from about 7 to about 13, or from about 7 to about 9.

Another aspect of the fourth additional exemplary embodiment is the method according to any of the preceding aspects of the fourth additional exemplary embodiment, wherein the stretching is performed under one of the following conditions:

at a drawing speed of more than 1500m/min, or more than 1700m/min, or more than 2000m/min, or more than 2500m/min, or more than 3000m/min, and less than 5000m/min, or less than 4000m/min, or less than 3100 m/min; or

Or in the absence of helium, or at a flow rate of less than 20 standard liters per minute (SLM), or less than 10SLM, or less than 5SLM, or 1SLM to 20SLM, or 1SLM to 10SLM, or 1SLM to 5SLM, or 5SLM to 20SLM, or 5SLM to 10 SLM.

Another aspect of the fourth additional exemplary embodiment is the method according to any of the preceding aspects of the fourth additional exemplary embodiment, wherein the primary coating composition is a radiation curable composition according to any of the aspects of the second additional exemplary embodiment.

Another aspect of the fourth additional exemplary embodiment is a coated optical fiber produced by the method according to any of the preceding aspects of the fourth additional exemplary embodiment.

A first aspect of a fifth additional exemplary embodiment of the present invention is a fiber optic cable comprising a plurality of coated optical fibers disposed within at least a portion of the cable, wherein at least one of the plurality of coated optical fibers comprises a primary coating that is a cured product of a radiation curable composition comprising

A urethane acrylate oligomer that is the reaction product of an isocyanate, a polyol, and an acrylate monomer;

a reactive diluent monomer; and

a free radical photoinitiator;

Another aspect of a fifth additional exemplary embodiment is the optical fiber cable according to the previous aspect, wherein at least one of the coated optical fibers has a mode field diameter of 8 μm to 10 μm at a wavelength of 1310nm or a mode field diameter of 9 μm to 13 μm at a wavelength of 1550 nm.

Another aspect of the fifth additional exemplary embodiment is the fiber optic cable according to any of the preceding two aspects, wherein at least one of the coated optical fibers is a single mode optical fiber configured with a wavelength of between 20 μ ι η²And 200 μm²The effective area therebetween.

Another aspect of the fifth additional exemplary embodiment is the fiber optic cable according to any of the preceding aspects of the fifth additional exemplary embodiment, wherein at least one of the coated optical fibers is a multimode optical fiber configured to have a wavelength of between 1500 μ ι η²And 3500 μm²The effective area therebetween.

Another aspect of the fifth additional exemplary embodiment is the optical fiber cable of any of the preceding aspects of the fifth additional exemplary embodiment, wherein the radiation curable composition has a liquid glass transition temperature (Tg, rheo); wherein the Tg, rheo of the radiation curable composition is less than-81.5 ℃, or is from-120 ℃ to-80 ℃, or from-115 ℃ to-80 ℃, or from-110 ℃ to-80 ℃, or from-100 ℃ to-80 ℃, or from-120 ℃ to-82 ℃, or from-115 ℃ to-82 ℃, or from-110 ℃ to-82 ℃, or from-100 ℃ to-82 ℃, or from-120 ℃ to-90 ℃, or from-115 ℃ to-90 ℃, or from-110 ℃ to-90 ℃, or from-100 ℃ to-90 ℃, or from-120 ℃ to-97 ℃, or from-113 ℃ to-97 ℃; wherein Tg, rheo is determined by fitting equation (8) to experimental viscosity versus temperature data for the radiation curable composition:

Wherein eta (T) is the viscosity of the composition at the temperature T, and eta₂₅Is the first viscosity.

Another aspect of the fifth additional exemplary embodiment is the optical fiber cable of any of the preceding aspects of the fifth additional exemplary embodiment, wherein the radiation curable composition is a liquid at the first, second, and third viscosities, and wherein the third viscosity is greater than 0.01 pascal-seconds (Pa-s), or greater than 0.10 Pa-s, or less than 1 Pa-s, or between about 0.01 Pa-s to about 1 Pa-s, or from about 0.03 Pa-s to about 0.8 Pa-s, or from about 0.03 Pa-s to about 0.5 Pa-s, or from about 0.03 Pa-s to about 0.4 Pa-s, or from about 0.05 Pa-s to about 1 Pa-s, or from about 0.05 Pa-s to about 0.5-s, or from about 0.1-s to about 0.8 Pa-s.

Another aspect of the fifth additional exemplary embodiment is the fiber optic cable according to any of the preceding aspects of the fifth additional exemplary embodiment, wherein the radiation curable composition is the radiation curable composition according to any one of the preceding claims.

Another aspect of the fifth additional exemplary embodiment is the optical fiber cable according to any of the preceding aspects of the fifth additional exemplary embodiment, wherein the plurality of coated optical fibers are coated by the method according to any of the aspects of the fourth additional exemplary embodiment.

Another aspect of the fifth additional exemplary embodiment is the optical fiber cable according to any of the preceding aspects of the fifth additional exemplary embodiment, wherein the plurality of coated optical fibers are optical fibers according to any of the aspects of the first additional exemplary embodiment.

Unless otherwise indicated, the term wt% refers to the amount by mass of a particular component relative to the entire liquid radiation curable composition into which it is incorporated.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Although the present invention has been described in detail with reference to the specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof as claimed.

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Radiation curable compositions for coating optical fibers and coatings produced therefrom

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