Optical fiber cable with high optical fiber count

文档序号：214377 发布日期：2021-11-05 浏览：22次中文

阅读说明：本技术 具有高光纤数的光纤光缆 (Optical fiber cable with high optical fiber count ) 是由 S·R·别克汉姆李明军 P·坦登 R·坦登于 2020-01-07 设计创作，主要内容包括：本公开提供了具有抗冲击性涂层体系的光纤(10)。所述光纤以低衰减为特征。所述涂层体系包括一次涂层(16)和二次涂层(18)。一次涂层和二次涂层具有减小的厚度,以在不牺牲保护的情况下提供低直径光纤。一次涂层具有高的撕裂强度并且抵抗由机械力造成的损伤。二次涂层具有高的抗刺穿性。光纤的外直径小于或等于190μm。(The present disclosure provides an optical fiber (10) having an impact resistant coating system. The optical fiber is characterized by low attenuation. The coating system includes a primary coating (16) and a secondary coating (18). The primary and secondary coatings have reduced thicknesses to provide low diameter optical fibers without sacrificing protection. The primary coating has high tear strength and is resistant to damage by mechanical forces. The secondary coating has a high puncture resistance. The outer diameter of the optical fiber is less than or equal to 190 μm.)

1. An optical fiber, comprising:

a core region comprising silica glass doped with an alkali metal oxide, the core region having a radius r₁And relative refractive index distribution Delta₁The radius r₁In the range of 3.0 μm to 10.0 μm, the relative refractive index distribution Δ₁Having a maximum relative refractive index delta in the range of-0.15% to 0.30%_{1 max}；

A cladding region surrounding and directly adjacent to the core region, the cladding region having a radius r in the range of 37.5 μm to 62.5 μm₄；

A primary coating surrounding and directly adjacent to the cladding region, the primary coating having a radius r₅An in situ modulus in the range of 0.05MPa to 0.30MPa, and a thickness r in the range of 8.0 μm to 20.0 μm₅–r₄(ii) a And

a secondary coating surrounding and directly adjacent to the primary coating, the secondary coating having a radius r less than or equal to 100.0 μm₆A Young's modulus of greater than 1600MPa, and a thickness r in the range of 8.0 μm to 20.0 μm₆–r₅。

2. The optical fiber of claim 1, wherein the silica glass is free of GeO₂。

3. The optical fiber of claim 1 or 2, wherein the radius r₁In the range of 4.0 μm to 8.0 μm.

4. The optical fiber of any of claims 1-3, wherein Δ_{1 max}In the range of-0.05% to 0.15%.

5. The optical fiber of any of claims 1-4, wherein the core region has a minimum relative refractive index Δ in the range of-0.20% to 0.10%_{1 minimum}And wherein, Δ_{1 max}And delta_{1 minimum}The difference is greater than 0.10%.

6. The optical fiber of any of claims 1-5, wherein the core region comprises a portion having a constant relative refractive index and a width of the portion in the radial direction of at least 2.0 μm.

7. The optical fiber of any of claims 1-6, wherein radius r₄In the range of 42.5 μm to 57.5 μm.

8. The optical fiber of any of claims 1-7, wherein the cladding region comprises an outer cladding region having a relative refractive index Δ in the range of-0.45% to-0.15%₄。

9. The optical fiber of any of claims 1-8, wherein the core region comprises an inner core region and an outer core region, the inner core region having a radius r in the range of 0.25 μ ι η to 3.0 μ ι η_aThe outer core region has a radius r₁。

10. The optical fiber of claim 9, wherein the inner core region has a relative refractive index profile described by an α -profile and an α value of less than 10, and the outer core region has a relative refractive index profile described by an α -profile and an α value of greater than 50.

11. The optical fiber of any of claims 1-10, wherein the cladding region comprises a depressed index cladding region directly adjacent to the core region, and surrounding and directly adjacent toAn outer cladding region of a depressed index cladding region having a radius r₃Relative refractive index delta in the range of-0.20% to-0.70%₃The outer cladding layer has a radius r₄And a relative refractive index delta in the range of-0.60% to 0.0%₄。

12. The optical fiber of claim 11, wherein the depressed index cladding region has a thickness in the range of 5.0 μm to 20.0 μm.

13. The optical fiber of claim 11 or 12, wherein the radius r₃In the range of 10.0 μm to 30.0 μm.

14. The optical fiber of any of claims 1-13, wherein radius r₅Less than or equal to 80 μm.

15. The optical fiber of any of claims 1-14, wherein thickness r₅–r₄In the range of 10.0 μm to 17.0 μm.

16. The optical fiber of any of claims 1-15, wherein the primary coating is a cured product of a coating composition comprising:

a radiation-curable monomer;

an adhesion promoter comprising an alkoxysilane compound or a mercapto-functional silane compound; and

an oligomer comprising:

a polyether urethane acrylate compound having the following formula:

wherein the content of the first and second substances,

R₁、R₂and R₃Independently selected from linear alkylene, branched alkyleneAlkyl or cycloalkylene;

y is 1, 2, 3 or 4; and is

x is between 40 and 100; and

a binary addition compound having the formula:

wherein the binary addition compound is present in the oligomer in an amount of at least 1.0 wt%.

17. The optical fiber of claim 16, wherein the binary addition compound is present in the oligomer in an amount of at least 1.0 wt.%.

18. The optical fiber of claim 16, wherein the binary addition compound is present in the oligomer in an amount of at least 3.5 wt.%.

19. The optical fiber according to any of claims 16-18, wherein the oligomer is a cured product of a reaction between:

a diisocyanate compound;

a hydroxy (meth) acrylate compound; and

a polyol compound having an unsaturation of less than 0.1 meq/g;

wherein the diisocyanate compound, the hydroxy (meth) acrylate compound, and the polyol compound are reacted at a molar ratio of n: m: p, respectively, wherein n is in the range of 3.0 to 5.0, m is in the range of ± 15% of 2n-4, and p is 2.

20. The optical fiber of any of claims 1-19, wherein radius r₆Less than or equal to 90.0 μm.

21. The optical fiber of any of claims 1-19, wherein radius r₆Less than or equal to 85.0 μm.

22. The optical fiber of any of claims 1-21, wherein the young's modulus is greater than 1800 MPa.

23. The optical fiber of any of claims 1-21, wherein the young's modulus is greater than 2000 MPa.

24. The optical fiber of any of claims 1-21, wherein the young's modulus is greater than 2500 MPa.

25. The optical fiber of any of claims 1-24, wherein thickness r₆–r₅In the range of 10.0 μm to 18.0 μm.

26. The optical fiber of any of claims 1-25, wherein the secondary coating is a cured product of a composition comprising:

a first monomer comprising a first bisphenol-A diacrylate compound.

27. The coating composition of claim 26, further comprising a second monomer comprising a second bisphenol-a diacrylate compound.

28. The coating composition of claim 27, wherein the first bisphenol-a diacrylate compound is an alkoxylated bisphenol-a diacrylate compound and the second bisphenol-a diacrylate compound is a bisphenol-a epoxy diacrylate compound.

29. The optical fiber of any of claims 1-25, wherein the secondary coating is a cured product of a composition comprising:

an alkoxylated bisphenol-A diacrylate monomer in an amount greater than 55 weight percent, the alkoxylated bisphenol-A diacrylate monomer having a degree of alkoxylation of from 2 to 16; and

a triacrylate monomer in an amount in the range of 2.0 to 25 wt.%, the triacrylate monomer comprising an alkoxylated trimethylolpropane triacrylate monomer having a degree of alkoxylation in the range of 2 to 16, or a tris [ (acryloyloxy) alkyl ] isocyanurate monomer.

30. The optical fiber of claim 29, wherein the alkoxylated bisphenol a diacrylate monomer is present in an amount of 60 to 75 wt.%.

31. The optical fiber of claim 29 or 30, wherein the alkoxylated bisphenol a diacrylate monomer has a degree of alkoxylation in the range of 2 to 8.

32. The optical fiber of any of claims 29-31, wherein the alkoxylated bisphenol a diacrylate monomer is an ethoxylated bisphenol a diacrylate monomer.

33. The optical fiber of any of claims 29-32, wherein triacrylate monomers are present in an amount of 8.0 to 15 wt.%.

34. The optical fiber according to any of claims 29-33, wherein the degree of alkoxylation of the alkoxylated trimethylolpropane triacrylate monomer is in the range of 2 to 8.

35. The optical fiber according to any of claims 29-34, wherein the alkoxylated trimethylolpropane triacrylate monomer is an ethoxylated trimethylolpropane triacrylate monomer.

36. The optical fiber of any of claims 29-35, wherein tris [ (acryloxy) alkyl ] isocyanurate monomer is tris (2-hydroxyethyl) isocyanurate triacrylate monomer.

37. The optical fiber of any of claims 29-36, further comprising a bisphenol a epoxy diacrylate monomer in an amount in the range of 5.0 wt.% to 20 wt.%.

38. The optical fiber of any of claims 1-37, wherein the secondary coating has an in situ glass transition temperature T_gGreater than 80 ℃.

39. The optical fiber of any of claims 1-37, wherein the secondary coating has an in situ glass transition temperature T_gGreater than 100 ℃.

40. The optical fiber of any of claims 1-39, wherein the normalized puncture load of the secondary coating is greater than 3.6x10^-4g/μm²。

41. The optical fiber of any of claims 1-39, wherein the normalized puncture load of the secondary coating is greater than 4.4x10^-4g/μm²。

42. The optical fiber of any of claims 1-41, wherein the optical fiber has an effective area greater than or equal to 90 μm²。

43. The optical fiber of any of claims 1-41, wherein the optical fiber has an effective area of greater than or equal to 130 μm²。

44. The optical fiber of any of claims 1-41, wherein the effective area of the optical fiber is greater than or equal to 145 μm²。

45. The optical fiber of any of claims 1-44, wherein the scaled load transfer parameter P of the secondary coating₁the/P (scaled) is less than 0.97.

46. The optical fiber of any of claims 1-44, wherein the secondary coating has a load transfer parameter P₁the/P is less than 0.0178.

47. The optical fiber of any of claims 1-46, wherein the optical fiber has an attenuation of less than or equal to 0.160dB/km at a wavelength of 1550 nm.

48. The optical fiber of any of claims 42 or 45-47, wherein the wire-mesh covered tube microbend loss of the optical fiber at 1550nm is less than 1.0 dB/km.

49. The optical fiber of any of claims 44-47, wherein the wire-mesh covered tube microbend loss of the optical fiber at 1550nm is less than 1.0 dB/km.

Technical Field

The present disclosure relates to fiber optic cables. More particularly, the present disclosure relates to fiber optic cables configured for use in undersea environments. Most particularly, the present disclosure relates to reduced diameter optical fibers and fiber optic cables having high fiber counts.

Background

Reduced diameter optical fibers are attractive for reducing the size of the cable required to accommodate a given number of optical fibers, increasing the number of optical fibers for a given diameter cable, reducing cable costs, efficiently using existing infrastructure to upgrade cable installations, and reducing the footprint of new cable installations.

In particular, the demand for undersea optical fiber transmission capacity is increasing continuously driven by the rapid growth in the traffic of the internet in each continent. In order to increase transmission capacity, wavelength division multiplexing has been used to increase the number of transmission channels, and advanced modulation formats have been developed to increase the data rate per channel. The number of channels and channel data rates have approached practical limits and increasing the number of fibers is inevitable.

Undersea optical fiber cables are designed to protect the internal optical fibers from water damage and other mechanical damage. The size of the deep sea cable is typically about 17-20mm in diameter for ease of installation and for ease of damage. Therefore, the space of the optical fiber is limited, and it is desired to increase the number of optical fibers without increasing the size of the optical cable.

Therefore, reduced diameter optical fibers are needed to increase the number of optical fibers in a fixed-size fiber optic cable. In particular, there is a need for optical fibers that provide the performance required for long distance transmission and that have reduced glass diameter and/or reduced coating thickness.

Disclosure of Invention

The present disclosure provides optical fibers having impact resistant coating systems. The optical fiber is characterized by low attenuation and low microbend loss performance. The coating system includes a primary coating and a secondary coating. The primary and secondary coatings have reduced thicknesses to provide low diameter optical fibers without sacrificing protection or increasing attenuation. The primary coating has high tear strength and is resistant to damage by mechanical forces, while at the same time it has a low modulus which contributes to the low microbend loss properties of the optical fiber. The secondary coating has a high puncture resistance. The outer diameter of the optical fiber is less than or equal to 200 μm.

The present description extends to:

an optical fiber, comprising:

A cladding region surrounding and directly adjacent to the core region, the cladding region having a radius r in the range of 37.5 μm to 62.5 μm₄；

Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide an overview or framework for understanding the nature and character of the claims.

The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings are illustrative of selected aspects of the disclosure and, together with the description, serve to explain the principles and operations of the methods, products, and compositions encompassed by the disclosure.

Drawings

FIG. 1 is a schematic illustration of a coated optical fiber according to one embodiment.

Fig. 2 is a schematic view of a representative fiber optic ribbon.

Fig. 3 is a schematic view of a representative fiber optic cable.

FIG. 4 depicts a cross-sectional view of an optical fiber having a core region, a depressed index cladding region, an outer cladding region, a primary coating and a secondary coating.

FIG. 5 depicts the relative refractive index profile of a glass optical fiber having a core region, a depressed-index cladding region, and an outer cladding region.

FIG. 6 depicts an exemplary relative refractive index profile of a glass optical fiber.

Fig. 7 shows the dependence of the piercing load on the cross-sectional area for the three secondary coatings.

Detailed Description

The present disclosure is provided as a teaching that can be implemented and can be more readily understood with reference to the following description, drawings, examples, claims. To this end, those skilled in the art will recognize and appreciate that various changes can be made to the various aspects of the embodiments described herein, while still obtaining the beneficial results. It will also be apparent that some of the desired benefits of this embodiment can be obtained by selecting some of the features without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations are possible and can even be desirable in certain circumstances and are a part of the present disclosure. Accordingly, it is to be understood that this disclosure is not limited to the particular compositions, articles, devices, and methods disclosed unless otherwise specified. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

In this specification and in the claims which follow, reference will be made to a number of terms which shall be defined to have the following meanings:

"include," "includes," or similar terms are intended to include, but are not limited to, i.e., are inclusive and not exclusive.

As used herein, the term "about" means that quantities, dimensions, formulas, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller as desired, such as reflection tolerances, conversion factors, rounding off, measurement error, and the like, as well as other factors known to those of skill in the art. When a value is referred to as being about a number or about equal to a number, the value is within ± 10% of the number. For example, a value of about 10 refers to a value between 9 and 11, inclusive. When the term "about" is used to describe a value or an endpoint of a range, it is to be understood that the disclosure includes the particular value or endpoint referenced. Whether or not the numerical values or endpoints of ranges in the specification are listed as "about," the numerical values or endpoints of ranges are intended to include both embodiments: one modified with "about" and the other not modified with "about". It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

The term "about" refers to items within all ranges unless otherwise indicated. For example, about 1, 2, or 3 is equivalent to about 1, about 2, or about 3, and also includes about 1 to 3, about 1 to 2, and about 2 to 3. The specific values and preferred values disclosed for the compositions, components, ingredients, additives and the like, as well as ranges thereof, are meant to be illustrative only and do not exclude other defined values or other values within the defined ranges. The compositions and methods of the present disclosure include compositions and methods having any value or any combination of values, specific values, more specific values, and preferred values described herein.

As used herein, the indefinite articles "a" or "an" and their corresponding definite articles "the" mean at least one, or one or more, unless otherwise indicated.

As used herein, contacting refers to direct contact or indirect contact. Direct contact refers to contact without the presence of intervening materials, and indirect contact refers to contact through one or more intervening materials. Elements that are in direct contact touch each other. Elements that are in indirect contact do not touch each other, but touch an intermediate material or series of intermediate materials, wherein at least one of the intermediate material or series of intermediate materials touches another element. The contacting elements may be rigidly or non-rigidly joined. Contacting refers to placing two elements in direct or indirect contact. Elements that are in direct (indirect) contact may be said to be in direct (indirect) contact with each other.

As used herein, "directly adjacent" means directly contacting, and "indirectly adjacent" means indirectly contacting. The term "adjacent" encompasses elements that are directly or indirectly adjacent to each other.

"optical fiber" refers to a waveguide having a glass portion surrounded by a coating. The glass portion includes a core and a cladding, and is referred to herein as a "glass optical fiber".

"radial position," "radius," or radial coordinate "r" refers to the radial position relative to the centerline of the optical fiber (r is 0).

The term "mode" refers to a pilot mode. Single mode fibers are fibers designed to support only the LP01 fundamental mode over a large fiber length (e.g., at least several meters), but in some cases may support multiple modes over short distances (e.g., tens of centimeters). We assume that the birefringence of the fiber is low enough to assume degeneracy (depenerate) of the two orthogonal polarization components of the LP01 mode and travel at the same phase velocity. Multimode fibers are designed to support the LP01 fundamental mode and at least one LP over a large fiber length_nmA high-order mode fiber, wherein either n ≠ 0 or m ≠ 1. The optical fiber disclosed herein is preferably a single mode optical fiber at a wavelength of 1550 nm.

The "operating wavelength" of an optical fiber is the wavelength at which the optical fiber operates. The operating wavelength corresponds to the wavelength of the guided mode. Representative operating wavelengths include 850nm, 980nm, 1060nm, 1310nm, and 1550nm, which are commonly used in telecommunication systems, optical data connections, and data centers. While a particular operating wavelength may be specified for an optical fiber, it is understood that a particular optical fiber may operate at multiple operating wavelengths and/or over a continuous range of operating wavelengths. Characteristics such as mode bandwidth and mode field diameter may vary with the operating wavelength, and the relative refractive index profile of a particular fiber may be designed to provide optimal performance at a particular operating wavelength, a particular combination of operating wavelengths, or a continuous range of particular operating wavelengths.

"refractive index" refers to the refractive index at a wavelength of 1550 nm.

"refractive index profile" is the relationship between refractive index or relative refractive index and radius. For relative refractive index profiles described herein as having a step boundary between adjacent core and/or cladding regions, typical process condition variations may prevent a sharp step boundary at the interface of adjacent regions. It should be understood that although the boundaries of the refractive index profile are described herein as step changes in refractive index, in practice, the boundaries may be rounded or otherwise deviate from a perfect step function characteristic. It is also understood that the relative refractive index values may vary with radial position within the core region and/or any of the cladding regions. When the relative refractive index varies with radial position in a particular region of the fiber (e.g., the core region and/or any of the cladding regions), the relative refractive index is expressed in terms of an actual or approximate functional dependence, or in terms of its value at a particular location within that region, or in terms of an average value that may be applied across the region. Unless otherwise specified, if the relative refractive index of a region (e.g., the core region and/or any of the cladding regions) is expressed in terms of a parameter applicable to the entire region (e.g., Δ or Δ%) or a single value, it is understood that the relative refractive index in that region is constant, or approximately constant, and corresponds to a single value, or the single numberThe value or parameter represents an average of the non-constant relative refractive indices that has a dependence on radial position in the region. For example, if "i" is a region of a glass fiber, then the parameter Δ_iIs the average of the relative refractive indices in this region as defined by equation (2) below, unless otherwise specified. The dependence of the relative refractive index on radial position may be tilted, curved or otherwise non-constant, whether as a result of design or normal manufacturing variations.

As used herein, "relative refractive index" is defined in equation (1) as:

wherein, unless otherwise specified, n_iIs the radial position r in the glass fibre_iAnd n unless otherwise specified_refIs the refractive index of pure silica glass. Thus, as used herein, the relative refractive index percent is relative to pure silica glass. As used herein, unless otherwise specified, the relative refractive index is represented by Δ (or "delta") or Δ% (or "delta%"), and the values are given in units of "%". The relative refractive index may also be expressed as Δ (r) or Δ (r)%.

Average relative refractive index (Delta) of a certain region of the optical fiber_ave) Determined according to equation (2):

wherein r is_{Inner part}Is the inner radius of the region, r_{Outer cover}Is the outer radius of the region and Δ (r) is the relative refractive index of the region.

The term "α -profile" refers to a relative refractive index profile Δ (r) having a functional form defined in equation (3) below:

wherein r is_oIs the radial position at which Δ (r) is maximum, r_z>r₀Is the radial position at which Δ (r) decreases to its minimum value, and r is at r_i≤r≤r_fIn which r is_iIs the initial radial position of the alpha-distribution, r_fIs the final radial position of the alpha-distribution and alpha is a real number. Delta (r) of the alpha distribution₀) May be referred to herein as Δ_{Maximum of}Alternatively, when a particular region i of the fiber is involved, it may be referred to as Δ_{i, max}. When the relative refractive index profile of the core region of the optical fiber is described by an alpha-profile, where r is₀Occurs at the center line (r ═ 0) and r_zCorresponding to the outer radius r of the core region₁And Δ₁(r₁) When 0, equation (3) is simplified to equation (4):

the term "superstic distribution" refers to a relative refractive index distribution Δ (r) having a functional form defined by equation (5):

where r is the radial distance from the centerline, γ is a positive number, and a is a radial scaling parameter such that when r ═ a, Δ₁＝Δ_{1 max}/e。

The "mode field diameter" or "MFD" of an optical fiber is defined in equation (6) as:

where f (r) is the transverse component of the electric field distribution of the guided optical signal, and r is the radial position in the optical fiber. The "mode field diameter" or "MFD" depends on the wavelength of the optical signal, andreported herein for a 1550nm wavelength. When referring to mode field diameter herein, the wavelength will be specifically indicated. Unless otherwise specified, mode field diameter refers to LP at the specified wavelength₀₁And (5) molding.

The "effective area" of the fiber is defined in equation (7) as:

where f (r) is the transverse component of the electric field of the guided optical signal, and r is the radial position in the optical fiber. "effective area" or "A_eff"depends on the wavelength of the optical signal and is herein understood to relate to a wavelength of 1550 nm.

The optical fiber disclosed herein includes a core region, a cladding region surrounding the core region, and a coating surrounding the cladding region. The core region and the cladding region are glass. The cladding region is a single homogeneous region or a plurality of regions of different relative refractive indices. The multiple cladding regions are preferably concentric regions. In a preferred embodiment, the cladding region comprises a depressed index cladding region. A depressed index cladding region is a cladding region having a lower relative refractive index than the adjacent core or outer cladding regions. The depressed index cladding region may also be referred to herein as a trench or trench region. A depressed index cladding region surrounds the core region and is surrounded by the outer cladding region. Depressed index cladding regions may contribute to a reduction in bending losses. The core region, cladding region, depressed-index cladding region, and outer cladding region are also referred to as the core, cladding, depressed-index cladding, and outer cladding, respectively.

Whenever used herein, the radial position r₁And relative refractive index delta₁Or Δ₁(r) relates to the core region, radial position r₂And relative refractive index delta₂Or Δ₂(r) relates to the inner cladding region, the radial position r₃And relative refractive index delta₃Or Δ₃(r) relates to the depressed index cladding region, radial position r₄And relative refractive index delta₄Or Δ₄(r) relates to the outer cladding region, radial position r₅Relates to thatPrimary coating and radial position r₆Secondary coatings are involved.

Relative refractive index delta₁(r) has a maximum value of Δ_{1 max}And a minimum value Δ_{1 minimum}. Relative refractive index delta₂(r) has a maximum value of Δ_{2 max}And a minimum value Δ_{2 min}. Relative refractive index delta₃(r) has a maximum value of Δ_{3 max}And a minimum value Δ_{3 min}. Relative refractive index delta₄(r) has a maximum value of Δ_{4 max}And a minimum value Δ_{4 min}. In embodiments where the relative refractive index is constant or approximately constant over a region, the maximum and minimum values of the relative refractive index are equal or approximately equal. Unless otherwise specified, if the relative refractive index of a region is reported as a single value, that single value corresponds to the average value of that region.

It will be appreciated that the central core region is substantially cylindrical in shape and that the surrounding inner cladding region, the surrounding depressed index cladding region, the surrounding outer cladding region, the surrounding primary coating, the surrounding secondary coating and the surrounding tertiary coating are substantially annular in shape. The annular region may be characterized in terms of an inner radius and an outer radius. Radial position r₁、r₂、r₃、r₄、r₅、r₆And r₇The outermost radius of the core, the outermost radius of the inner cladding, the outermost radius of the depressed index cladding, the outermost radius of the outer cladding, the outermost radius of the primary coating, the outermost radius of the secondary coating, and the outermost radius of the tertiary coating are referred to herein, respectively. In embodiments without a tertiary coating, the radius r₆Also corresponding to the outer radius of the optical fiber. Radius r when three coats are present₇Corresponding to the outer radius of the optical fiber.

When two regions are directly adjacent to each other, the outer radius of the inner one of the two regions coincides with the inner radius of the outer one of the two regions. In one embodiment, for example, an optical fiber includes a depressed index cladding region surrounded by and directly adjacent to an outer cladding region. In such an embodiment, the radius r₃Corresponding to the depressed refractive indexThe outer radius of the cladding region and the inner radius of the outer cladding region. In embodiments where the relative refractive index profile comprises a depressed index cladding region directly adjacent to the core, the radial position r₁Corresponding to the outer radius of the core and the inner radius of the depressed index cladding region.

The following terminology applies to embodiments in which the relative index profile includes an inner cladding region surrounding and directly adjacent to the core, a depressed-index cladding region surrounding and directly adjacent to the inner cladding region, an outer cladding region surrounding and directly adjacent to the depressed-index cladding region, a primary coating surrounding and directly adjacent to the outer cladding region, and a secondary coating surrounding and directly adjacent to the primary coating. Radial position r₂And radial position r₁The difference between is referred to herein as the thickness of the inner cladding region. Radial position r₃And radial position r₂The difference between is referred to herein as the thickness of the depressed index cladding region. Radial position r₄And radial position r₃The difference between is referred to herein as the thickness of the outer cladding region. Radial position r₅And radial position r₄The difference between is referred to herein as the thickness of the primary coating. Radial position r₆And radial position r₅The difference between is referred to herein as the thickness of the secondary coating.

The following terminology applies to embodiments in which the depressed index cladding region is directly adjacent to the core region and the outer cladding region is directly adjacent to the depressed index cladding region. Radial position r₃And radial position r₁The difference between is referred to herein as the thickness of the depressed index cladding region. Radial position r₄And radial position r₃The difference between is referred to herein as the thickness of the outer cladding region. Radial position r₅And radial position r₄The difference between is referred to herein as the thickness of the primary coating. Radial position r₆And radial position r₅The difference between is referred to herein as the thickness of the secondary coating.

As will be described further below, the relative indices of the core region, depressed index cladding region, and outer cladding region are not the same. Each region is formed of doped or undoped silica glass. The change in refractive index relative to undoped silica glass is achieved by adding different levels of positive or negative dopants to provide the target refractive index or refractive index profile using techniques known to those skilled in the art. A positive dopant is a dopant that increases the refractive index of the glass relative to an undoped glass composition. A down-dopant is a dopant that decreases the refractive index of the glass relative to an undoped glass composition. In one embodiment, the undoped glass is a pure silica glass. When the undoped glass is pure silica glass, the positive dopants include Cl, Br, Ge, Al, P, Ti, Zr, Nb, and Ta, and the negative dopants include F and B. The constant refractive index region may be formed by being undoped or by being doped at a uniform concentration. The variable refractive index region is formed by a non-uniform spatial distribution of dopants and/or by including different dopants in different regions.

The coatings described herein are formed from curable coating compositions. The curable coating composition includes one or more curable components. As used herein, the term "curable" is intended to mean that the component includes one or more curable functional groups capable of forming covalent bonds that participate in the attachment of the component to itself or to other components of the coating composition when the component is exposed to a suitable source of curing energy. The product obtained by curing the curable coating composition is herein referred to as the cured product of the composition. The cured product is preferably a polymer. The curing process is energy induced. The form of energy includes radiant energy or thermal energy. In a preferred embodiment, curing occurs by radiation, wherein radiation refers to electromagnetic radiation. Curing by radiation induction is referred to herein as radiation curing or photocuring. Radiation curable components are components that can be induced to undergo a curing reaction when exposed to radiation of a suitable wavelength of suitable intensity for a sufficient time. Suitable wavelengths include wavelengths in the infrared, visible or ultraviolet portions of the electromagnetic spectrum. The radiation curing reaction occurs in the presence of a photoinitiator. The radiation curable components may also be thermally curable. Similarly, a thermally curable component is a component that can be induced to undergo a curing reaction when exposed to thermal energy of sufficient intensity for a sufficient time. The thermally curable component may also be radiation curable.

The curable component includes one or more curable functional groups. Curable components having only one curable functional group are referred to herein as monofunctional curable components. Curable components having two or more curable functional groups are referred to herein as multifunctional curable components. The multifunctional curable component includes two or more functional groups capable of forming covalent bonds during the curing process, and may introduce cross-linking into the polymeric network formed during the curing process. The multifunctional curable component may also be referred to herein as a "crosslinker" or "curable crosslinker". The curable component includes a curable monomer and a curable oligomer. Examples of functional groups involved in the formation of covalent bonds during curing are identified below.

When the term "molecular weight" is used for a polyol, it means the number average molecular weight (M)_n)。

The term "(meth) acrylate" means methacrylate, acrylate, or a combination of methacrylate and acrylate.

Values for young's modulus,% elongation, and tear strength refer to values determined by the procedure described herein under the measurement conditions.

Reference will now be made in detail to the illustrative embodiments of the present description.

The present specification relates to a curable coating composition, a coating formed from the curable coating composition, and a coated article coated or encapsulated by the coating and obtained by curing the curable coating composition. In a preferred embodiment, the curable coating composition is a composition for forming a coating for an optical fiber, the coating is an optical fiber coating, and the coated article is a coated optical fiber. The present specification also relates to methods of preparing the curable coating compositions, methods of forming coatings from the curable coating compositions, and methods of coating optical fibers with the curable coating compositions.

One embodiment relates to an optical fiber. An optical fiber includes a glass optical fiber surrounded by a coating. One example of an optical fiber is shown in the cross-sectional schematic of fig. 1. Optical fiber 10 includes a glass optical fiber 11 surrounded by a primary coating 16 and a secondary coating 18. Further description of the glass fiber 11, primary coating 16, and secondary coating 18 is provided below.

Fig. 2 illustrates a fiber optic ribbon 30. Ribbon 30 includes a plurality of optical fibers 20 and a matrix 32 encapsulating the plurality of optical fibers. As described above, the optical fiber 20 includes a core region, a cladding region, a primary coating, and a secondary coating. As described above, the optical fiber 20 may also include a tertiary coating. The secondary coating may include a pigment. The optical fibers 20 are arranged in a substantially planar and parallel relationship with respect to each other. The optical fibers in the fiber optic ribbons are encapsulated by the ribbon matrix 32 in any known configuration (e.g., edge-bonded ribbon, thin encapsulated ribbon, thick encapsulated ribbon, or multi-layer ribbon) by conventional methods of manufacturing fiber optic ribbons. In fig. 2, fiber optic ribbon 30 contains twelve (12) optical fibers 20; however, it should be apparent to those skilled in the art that any number of optical fibers 20 (e.g., two or more) may be used to form a ribbon 30 configured for a particular use. The tape substrate 32 may be formed from the same composition used to prepare the secondary coating, or the tape substrate 32 may be formed from a different composition that is otherwise compatible with the application.

Fig. 3 illustrates a fiber optic cable 40. The cable 40 includes a plurality of optical fibers 20 surrounded by a jacket 42. The optical fiber 20 may be densely or loosely packed into a catheter enclosed by the inner surface 42 of the sheath 42. The number of optical fibers placed in the jacket 42 is referred to as the "fiber count" of the fiber optic cable 40. The jacket 42 is formed of an extruded polymeric material and may include multiple concentric layers of polymeric or other materials. Fiber optic cable 40 may include one or more strength members (not shown) embedded within jacket 42 or disposed within a conduit defined by inner surface 44. The reinforcing members comprise fibers or rods that are more rigid than the jacket 42. The reinforcing member is made of metal, woven steel, glass reinforced plastic, fiberglass, or other suitable material. The fiber optic cable 40 may include other layers (e.g., armor layers, moisture barriers, ripcords, etc.) surrounded by a jacket 42. The fiber optic cable 40 may have a stranded loose tube core or other fiber optic cable configuration.

A glass optical fiber. The optical fibers disclosed herein include glass optical fibers having a core region, a cladding region surrounding the core region, and a coating surrounding the cladding region. The core region and the cladding region are glass. As is well known to those skilled in the art, glass fiber 11 includes a core region 12 and a cladding region 14. The core region 12 has a higher refractive index than the cladding region 14, and the glass fiber 11 functions as a waveguide.

In many applications, the core region and the cladding region have identifiable core-cladding boundaries. Alternatively, the core region and the cladding region may not have a distinct boundary. One type of fiber is a step index fiber. Another type of fiber is a graded index fiber, whose core region has a refractive index that varies with distance from the center of the fiber. An example of a graded-index optical fiber is an optical fiber in which the relative refractive index profile of the core region has an α -profile defined by equation (4) above or an ultra-gaussian profile defined by equation (5) above.

Fig. 4 shows a schematic cross-sectional view of an optical fiber. In fig. 4, optical fiber 46 includes a core region 48, a cladding region 50, a primary coating 56, and a secondary coating 58. Cladding region 50 includes depressed index cladding region 53 and outer cladding region 55.

In one embodiment, an optical fiber comprises: a depressed-index cladding region surrounding the core, an outer cladding region surrounding the depressed-index cladding region, a primary coating surrounding the outer cladding region, and a secondary coating surrounding the primary coating. The depressed-index cladding region is directly adjacent the core region, the outer cladding region is directly adjacent the depressed-index cladding region, the primary coating is directly adjacent the outer cladding region, and the secondary coating is directly adjacent the primary coating. Optionally, in the foregoing embodiments, the tertiary layer (e.g., ink layer) surrounds or is directly adjacent to the secondary coating.

Fig. 5 represents a representative relative refractive index profile of a glass optical fiber. FIG. 5 shows a rectangular trench profile of a glass fiber 60, the glass fiber 60 having a core region (1), a depressed-index cladding region (3), and an outer claddingA region (4), the core region (1) having an outer radius r₁And relative refractive index delta₁And has a maximum relative refractive index Delta_{1 max}Said depressed index cladding region (3) being at a radial position r₁Extending to a radial position r₃And has a relative refractive index delta₃Said outer cladding region (4) being from a radial position r₃Extending to a radial position r₄And has a relative refractive index delta₄. In the profile of fig. 5, the depressed-index cladding region (3) may be referred to herein as a trench and may have a constant or average relative refractive index that is less than the relative refractive index of the outer cladding region (4). The core region (1) has the highest average and maximum relative refractive index in the profile. The core region (1) may include a lower index region (referred to in the art as "centerline downtilt") (not shown) at or near the centerline.

In the embodiment shown in fig. 5, the relative refractive index of the core region (1) of the glass fiber is described by an α -profile. Radial position r of the alpha distribution₀(corresponds to. DELTA.)_{1 max}) Corresponding to the centre line of the fibre (r ═ 0) and alpha-distributed radial position r_zCorresponding to the core radius r₁. In embodiments with centerline downtilt, the radial position r₀Slightly offset from the centerline of the fiber. In other embodiments, the core region (1) shown in fig. 5 is a step-index relative-refractive-index profile or a super-gaussian relative-refractive-index profile, rather than an α -profile. In other embodiments, the core region (1) has a relative refractive index profile that is not defined by any of an alpha-profile, a super-gaussian profile, or a step-index profile. In some embodiments, the relative refractive index Δ₁Decreasing in a radial direction away from the centerline. In other embodiments, the relative refractive index Δ₁At the center line and r₁At some radial position in between, and between the centerline and r₁And other radial positions in between include constant or substantially constant values.

In FIG. 5, the transition region 62 from the core region (1) to the depressed-index cladding region (3) and from the depressed-index cladding region (3) to the outer cladding region(4) The transition region 64 of (a) is shown as a step change. It will be appreciated that the step change is an idealised situation, and in practice the filtering zone 62 and the transition zone 64 may not be strictly vertical. Instead, the transition region 62 and/or the transition region 64 may have a slope or curvature. When the transition region 62 and/or the transition region 64 are not perpendicular, the inner radius r of the depressed index cladding region (3)₁And an outer radius r₃Corresponding to the midpoints of the transition regions 62 and 64, respectively. The mid-point corresponds to half the depth 67 of the depressed index cladding region (3). In some embodiments, there is an inner cladding region (2) between the core region (1) and the depressed index cladding region (3).

Relative refractive index Δ in the relative refractive index profile shown in fig. 5₁、Δ₃And Δ₄Satisfies the following condition: delta_{1 max}>Δ₄>Δ₃。

The core region comprises silica glass. Preferably, the silica glass of the core region is Ge-free; that is, the core region comprises silica glass without Ge. The silica glass of the core region is undoped silica glass, positively doped silica glass, and/or negatively doped silica glass. Positively doped silica glasses comprising alkali metal oxide (e.g., Na) doping₂O、K₂O、Li₂O、Cs₂O or Rb₂O) silica glass. The negatively doped silica glass comprises a F-doped silica glass. In some embodiments, the core region is co-doped with alkali metal oxide and fluorine. K in the core₂The O concentration, expressed in terms of the amount of K, is in the range of 20ppm to 1000ppm, alternatively 35ppm to 500ppm, alternatively 50ppm to 300ppm, where ppm refers to parts per million by weight. Except for K₂The amount of alkali metal oxide other than O present corresponds to K determined from the amount of K as described above₂Molar equivalents of O.

In some embodiments, the core region comprises a positive dopant and a negative dopant, wherein the concentration of the positive dopant is highest at the centerline (r-0) and at the radius r₁Is lowest and the concentration of the down dopant is at the center line (r-0)Lowest, and at radius r₁Is highest. In such an embodiment, the relative refractive index Δ₁May have a positive value near the centerline (r ═ 0) and at radius r₁Decreases to a negative value.

In one embodiment, the core region is a segmented core region comprising an inner core region surrounded by an outer core region, wherein the inner core region comprises positively doped silica glass and has a positive maximum relative refractive index Δ_{1 max}And the outer core region comprises negatively doped silica glass and has a negative minimum relative refractive index delta_{1 minimum}. The positively doped silica glass of the inner core region includes a positive dopant, or a combination of a positive dopant and a negative dopant. In embodiments where the inner core region includes a combination of positive and negative dopants, the relative concentrations of the positive and negative dopants are adjusted to provide a net positive value of the maximum relative refractive index. In embodiments where the outer core region includes a combination of positive and negative dopants, the relative concentrations of the positive and negative dopants are adjusted to provide a net negative value of the relative refractive index. In embodiments with a segmented core, Δ₁(and. DELTA. -)_{1 max}And Δ_{1 minimum}) Involving the entire core region, including the inner and outer core regions, r₁Corresponding to the outer radius of the outer core region, r_aCorresponding to the outer radius of the inner core region. The boundary between the inner core region and the outer core region occurs at a radial position r_aWhere r is_a<r₁。

In some embodiments, the relative refractive index of the core region of the glass optical fiber is described by an α -profile, wherein the α value is in the range of 1.5 to 10, or in the range of 1.7 to 8.0, or in the range of 1.8 to 6.0, or in the range of 1.9 to 5.0, or in the range of 1.95 to 4.5, or in the range of 2.0 to 4.0, or in the range of 10 to 100, or in the range of 11 to 40, or in the range of 12 to 30. As the value of α increases, the relative refractive index profile more closely approaches the step index profile. In some embodiments having segmented core regions, one or both of the inner and outer core regions have a relative refractive index described by an alpha profile, and the alpha values are as described herein.

Outer radius r of the core region₁In the range of 3.0 μm to 10.0 μm, or in the range of 3.5 μm to 9.0 μm, or in the range of 4.0 μm to 8.0 μm. In some embodiments, the core region comprises a portion having a constant or substantially constant relative refractive index, the portion having a width in the radial direction of at least 1.0 μm, or at least 2.0 μm, or at least 3.0 μm, or at least 4.0 μm, or at least 5.0 μm, or in the range of 1.0 μm to 6.0 μm, or in the range of 2.0 μm to 5.0 μm. In one embodiment, the portion of the core region having a constant or substantially constant relative refractive index has a delta_{1 minimum}Relative refractive index. In embodiments having a segmented core region, the radius r_aIn the range of 0.25 μm to 3.0 μm, or in the range of 0.5 μm to 2.5 μm, or in the range of 0.75 μm to 2.0 μm.

Relative refractive index Delta of core region₁Or Δ_{1 max}In the range of-0.15% to 0.30%, or in the range of-0.10% to 0.20%, or in the range of-0.05% to 0.15%, or in the range of 0% to 0.10%. Minimum relative refractive index delta of core_{1 minimum}In the range of-0.20% to 0.10%, or in the range of-0.15% to 0.05%, or in the range of-0.15% to 0.00%. Delta_{1 max}And delta_{1 minimum}Is greater than 0.05%, or greater than 0.10%, or greater than 0.15%, or greater than 0.20%, or in the range of 0.05% to 0.30%, or in the range of 0.10% to 0.25%.

In some embodiments, the relative refractive index of the core region is described by a step index profile having a refractive index corresponding to Δ_{1 max}A constant or substantially constant value of.

In embodiments where the relative refractive index profile comprises a depressed index cladding region, the depressed index cladding region comprises negatively doped silica glass. A preferred negative dopant is F (fluorine). The concentration of F (fluorine) is in the range of 0.1 to 2.5 wt.%, or in the range of 0.25 to 2.25 wt.%, or in the range of 0.3 to 2.0 wt.%.

In embodiments where the relative refractive index profile includes a depressed index cladding region, the relative refractive index Δ₃Or Δ_{3 min}In the range of-0.1% to-0.8%, or in the range of-0.2% to-0.7%, or in the range of-0.3% to-0.6%. Relative refractive index delta₃Preferably constant or substantially constant. Delta_{1 max}And delta₃Difference (or. DELTA.)_{1 max}And delta_{3 min}A difference of, or Δ₁And delta₃A difference of, or Δ₁And delta_{3 min}A difference) of greater than 00.20%, or greater than 0.30%, or greater than 0.40%, or greater than 0.50%, or greater than 0.60%, or in the range of 0.25% to 0.70%, or in the range of 0.35% to 0.60%. Delta_{1 minimum}And delta₃Difference (or. DELTA.)_{1 minimum}And delta_{3 min}A difference) of greater than 0.20%, or greater than 0.30%, or greater than 0.40%, or greater than 0.50%, or in the range of 0.20% to 0.60%, or in the range of 0.25% to 0.50%.

The inner radius of the depressed index cladding region is r₁And has the values specified above. Outer radius r of depressed index cladding region₃In the range of 10.0 μm to 30.0 μm, or in the range of 12.5 μm to 27.5 μm, or in the range of 15.0 μm to 25.0 μm. Thickness r of depressed index cladding region₃–r₁In the range of 2.0 μm to 22.0 μm, or in the range of 5.0 μm to 20.0 μm, or in the range of 7.5 μm to 17.5 μm, or in the range of 10.0 μm to 15.0 μm.

Relative refractive index delta of the outer cladding region₄Or Δ_{4 max}In the range of-0.60% to 0.0%, or in the range of-0.55% to-0.05%, or in the range of-0.50% to-0.10%, or in the range of-0.45% to-0.15%. Relative refractive index delta₄Preferably constant or substantially constant. Delta₄And delta₃Difference (or. DELTA.)₄And delta_{3 min}A difference of, or Δ_{4 max}And delta₃A difference of, or Δ_{4 max}And delta_{3 min}A difference) of greater than 0.01%, or greater than 0.02%, or greater than 0.03%, or in the range of 0.01% to 0.10%, or in the range of 0.02% to 0.0Within a range of 7%.

The inner radius of the outer cladding region is r₃And has the values specified above. Outer radius r₄Preferably of low value to minimize the diameter of the glass fibers and thereby promote high fiber count in the cable. Outer radius r of the outer cladding region₄Less than or equal to 62.5 μm, or less than or equal to 60.0 μm, or less than or equal to 57.5 μm, or less than or equal to 55.0 μm, or less than or equal to 52.5 μm, or less than or equal to 50.0 μm, or in the range of 37.5 μm to 62.5 μm, or in the range of 40.0 μm to 60.0 μm, or in the range of 42.5 μm to 57.5 μm, or in the range of 45.0 μm to 55.0 μm. Thickness r of the outer cladding region₄–r₃In the range of 10.0 μm to 50.0 μm, or in the range of 15.0 μm to 45.0 μm, or in the range of 20.0 μm to 40.0 μm, or in the range of 25.0 μm to 35.0 μm.

Fig. 6 illustrates a representative relative refractive index profile of the manufactured glass optical fiber. Relative index profiles 70, 80, 90, and 100 include a core region, a depressed index cladding region, and an outer cladding region at increasing radial positions. The width and depth of the depressed index cladding region are varied. The relative index profile 70 includes a transition region 73 between the core region and the depressed-index cladding region, and a transition region 77 between the depressed-index region and the outer cladding region. For the relative refractive index profile 70, the transition region 73 occurs at a radius r₁And transition region 77 occurs at radius r₃To (3). The relative index profile 80 includes a transition region 83 between the core region and the depressed-index cladding region, and a transition region 87 between the depressed-index region and the outer cladding region. For the relative refractive index profile 80, the transition region 83 occurs at a radius r₁And transition region 87 occurs at radius r₃To (3). The relative index profile 90 includes a transition region 93 between the core region and the depressed-index cladding region, and a transition region 97 between the depressed-index region and the outer cladding region. For the relative refractive index profile 90, the transition region 93 occurs at a radius r₁And transition region 97 occurs at radius r₃To (3). The relative refractive index profile 100 is included in the coreA transition region 103 between the region and the depressed-index cladding region, and a transition region 107 between the depressed-index region and the outer cladding region. For the relative refractive index profile 100, the transition region 103 occurs at a radius r₁And the transition region 107 occurs at a radius r₃To (3).

In one embodiment, the core region of a relative refractive index profile of the type shown in FIG. 6 is a segmented core region, wherein the radius r₁As shown, occurs at the transition zone and corresponds to the outer radius of the outer core zone and has an inner core zone with an outer radius r_aSo that r is_a<r₁. In one embodiment, the inner core region and the outer core region each have a relative refractive index profile described by an alpha-profile. In one embodiment, the inner core region has an α value of less than 20, or less than 10, or less than 5.0, or less than 3.0, or less than 2.0, or in the range of 1.0 to 20, or in the range of 1.5 to 10, or in the range of 1.7 to 5.0, or in the range of 1.8 to 3.0, and the outer core region has an α value of greater than 20, or greater than 50, or greater than 100, or greater than 150, or greater than 200, or in the range of 20 to 300, or in the range of 50 to 250, or in the range of 100 to 200. In another embodiment, the inner core region has a relative refractive index profile described by an alpha-profile and the outer core region has a relative refractive index profile described by a step index profile. In another embodiment, the inner core region has a relative refractive index profile described by an alpha-profile and the outer core region has a relative refractive index profile described by a rounded step index profile.

In one embodiment, the inner core region is alkali metal doped silica and the outer core region is halide doped silica. Halide doped silica includes silica doped with one or more of Cl, F and Br. In one embodiment, the inner core region is doped with K₂O, and the outer core region is doped with F or a combination of F and Cl.

Implementation of relative refractive index profiles in the inner and outer core regions, respectively, described by the alpha-profileIn the formula, the radius r_aBy the function χ given for equation (8)²Minimization was performed to determine:

wherein, f (r)_i) Is the alpha-distribution function of the inner core region, g (r)_j) Is the alpha-distribution function of the outer core region, g (r)_a) Is r_j＝r_aG (r) of_j) Value of (a), Δ (r)_i) Is the measured relative refractive index profile, Δ (r), of the inner core region_j) Is the measured relative refractive index profile of the outer core region, and the index "i" indicates the radial position r in the inner core region_iThe index "j" indicates the radial position r in the outer core region_j，0<r_i<r_a，r_a≤r_j≤r_bThe index "a" corresponds to r_i＝r_aIs a value corresponding to the index "i", the index "b" is a value corresponding to r_j＝r₁The value of index "j" of (a).

Effective area A associated with relative refractive index profiles 70, 80, 90 and 100 at a wavelength of 1550nm_{Is effective}Are respectively 76 μm²、86μm²、112μm²And 150 μm²。

Effective area A of the optical fiber disclosed herein at a wavelength of 1550nm_{Is effective}Greater than 70 μm²Or greater than 90 μm²Or greater than 110 μm²Or greater than 130 μm²Or greater than 145 μm²Or at 70 μm²To 175 μm²In the range of (1), or in the range of 90 μm²To 170 μm²In the range of (1), or in the range of 105 μm²To 165 μm²In the range of (1), or in the range of 115 μm²To 160 μm²Within the range of (1).

The attenuation of the optical fiber disclosed herein is less than or equal to 0.170dB/km, or less than or equal to 0.165dB/km, or less than or equal to 0.160dB/km, or less than or equal to 0.155dB/km, or less than or equal to 0.150dB/km at a wavelength of 1550 nm.

And (3) coating the optical fiber. The transmission of light through an optical fiber is largely dependent on the nature of the coating applied to the glass fiber. The coating typically includes a primary coating and a secondary coating, wherein the secondary coating surrounds the primary coating and the primary coating contacts the glass optical fiber (which includes a central core region surrounded by a cladding region). The secondary coating is a material that is harder (higher young's modulus) than the primary coating and is designed to protect the glass optical fiber from damage caused by abrasion or external forces generated during processing, handling, and installation of the optical fiber. The primary coating is a softer (lower young's modulus) material than the secondary coating and is designed to buffer or dissipate stresses generated by forces applied to the outer surface of the secondary coating. Stress dissipation in the primary coating attenuates the stress and minimizes the stress reaching the glass fiber. The primary coating is particularly important in dissipating the stresses due to microbending that the optical fiber undergoes when deployed in a fiber optic cable. It is desirable to minimize the microbend stress transmitted to the glass fiber because the microbend stress creates a local perturbation in the refractive index profile of the glass fiber. The local refractive index perturbations result in a loss of intensity of light transmitted through the glass fiber. By dissipating the stress, the primary coating minimizes microbend-induced strength loss.

Preferably, the refractive index of primary coating 16 is higher than the refractive index of the cladding region of the glass fiber to enable it to remove false optical signals from the core region. The primary coating should maintain sufficient adhesion to the glass fiber during thermal and hydrolytic aging, but yet be peelable from the glass fiber for splicing.

The primary and secondary coatings are typically formed by applying a curable coating composition as a viscous liquid to the glass optical fiber and curing. The optical fiber may further include a tertiary coating (not shown) surrounding the secondary coating. The tertiary coating may include pigments, inks, or other colorants to mark the optical fiber for identification purposes, and typically has a young's modulus similar to that of the secondary coating.

A primary coating composition. The primary coating is the cured product of the curable primary coating composition. The curable primary coating composition provides a primary coating for optical fibers that exhibits a low young's modulus, low pullout force, and strong cohesion. The curable primary coating composition is also capable of forming a primary coating with clean strippability and high resistance to defect formation during stripping operations. The low pullout force promotes clean peel of the primary coating with minimal residue, while the strong cohesive force inhibits the initiation and propagation of defects within the primary coating when the primary coating is subjected to the peel force. Even for optical fibers with reduced primary coating thickness, low loss and low microbending loss properties are expected. Primary coatings exhibit these advantages even when the thickness is reduced.

The primary coating is the cured product of a radiation curable primary coating composition comprising oligomers, monomers and photoinitiators, and optionally additives. The following disclosure describes oligomers for use in: a radiation-curable primary coating composition, a radiation-curable primary coating composition comprising at least one oligomer, a cured product of the radiation-curable primary coating composition comprising at least one oligomer, an optical glass fiber coated with the radiation-curable primary coating composition and the composition comprising at least one oligomer, and an optical glass fiber coated with the cured product of the radiation-curable primary coating composition and the coating composition comprising at least one oligomer.

The oligomer preferably includes a polyether urethane diacrylate compound and a binary addition compound. In one embodiment, the polyether urethane diacrylate compound has a linear molecular structure. In one embodiment, the oligomer is formed from a reaction between a diisocyanate compound, a polyol compound, and a hydroxy acrylate compound, wherein the reaction produces a polyether urethane diacrylate compound as a main product (majority product) and a di-addition compound as a side product (minority product). When the isocyanate group of the diisocyanate compound reacts with the alcohol group of the polyol, the reaction forms a urethane linkage. The hydroxy acrylate compound reacts to quench residual isocyanate groups present in the composition formed by the reaction of the diisocyanate compound and the polyol compound. As used herein, the term "quenching" refers to the conversion of an isocyanate group by chemical reaction with the hydroxyl group of a hydroxyacrylate compound. Quenching the residual isocyanate groups with a hydroxy acrylate compound converts the terminal isocyanate groups to terminal acrylate groups.

One preferred diisocyanate compound is represented by formula (I):

O＝C＝N-R₁-N＝C＝O (I)

which comprises a linked group R₁Two terminal isocyanate groups separated. In one embodiment, the linking group R₁Including alkylene groups. Linking group R₁The alkylene group of (a) is a linear (e.g., methylene or ethylene), branched (e.g., isopropylidene) or cyclic (e.g., cyclohexylidene, phenylene). The cyclic group is aromatic or non-aromatic. In some embodiments, the linking group R₁Is a 4,4 '-methylenebis (cyclohexyl) group, and the diisocyanate compound is 4, 4' -methylenebis (cyclohexyl isocyanate). In some embodiments, the linking group R₁Lack aromatic groups, or lack phenylene groups, or lack oxyphenylene groups.

The polyol is represented by formula (II):

wherein R is₂Comprising alkylene, -O-R₂-is a repeating alkyleneoxy group, and x is an integer. Preferably, x is greater than 20, or greater than 40, or greater than 50, or greater than 75, or greater than 100, or greater than 125, or greater than 150, or in the range of 20 to 500, or in the range of 20 to 300, or in the range of 30 to 250, or in the range of 40 to 200, or in the range of 60 to 180, or in the range of 70 to 160, or in the range of 80 to 140. R₂Preferably a linear or branched alkylene group, such as methylene, ethylene, propylene (n-propylene, isopropylene, or a combination thereof), or butylene (n-butylene, isobutylene, sec-butylene, tert-butylene, or a combination thereof). The polyol may be a polyalkylene oxide, such as polyethylene oxide, or a polyalkylene glycol, such as polypropylene glycol. Polypropylene glycol is a preferred polyol. The polyol has a molecular weight of greater than 1000g/mol (g/mol), or greater than 2500g/mol, or greater than 5000g/mol, or greater than 7500g/mol, or greater than 10000g/mol, or in the range of 1000g/mol to 20000g/mol, or in the range of 2000g/mol to 15000g/mol, or in the range of 2500g/mol to 12500g/mol, or in the range of 2500g/mol to 10000g/mol, or in the range of 3000g/mol to 7500g/mol, or in the range of 3000g/mol to 6000g/mol, or in the range of 3500g/mol to 5500 g/mol. In some embodiments, the polyol is polydisperse and includes molecules spanning a range of molecular weights, so all molecules combine to provide the number average molecular weight specified above.

The polyol has an unsaturation of less than 0.25meq/g (milliequivalents/g), or less than 0.15meq/g, or less than 0.10meq/g, or less than 0.08meq/g, or less than 0.06meq/g, or less than 0.04meq/g, or less than 0.02meq/g, or less than 0.01meq/g, or less than 0.005meq/g, or in the range of 0.001meq/g to 0.15meq/g, or in the range of 0.005meq/g to 0.10meq/g, or in the range of 0.01meq/g to 0.05meq/g, or in the range of 0.02meq/g to 0.10meq/g, or in the range of 0.02meq/g to 0.05 meq/g. Unsaturation as used herein refers to a value determined by standard methods reported in ASTM D4671-16. In the process, a polyol is reacted with mercuric acetate and methanol in a methanol solution to produce an acetoxymercuric methoxy compound and acetic acid. The reaction of the polyol with the mercury acetate is equimolar and the amount of acetic acid released is determined by titration with an ethanolic solution of potassium hydroxide, providing a measure of unsaturation as used herein. To prevent excess mercury acetate from interfering with the titration of acetic acid, sodium bromide is added to convert the mercury acetate to bromide.

The reaction to form the oligomer also includes the addition of a hydroxy acrylate compound to react with terminal isocyanate groups present in the unreacted starting materials (e.g., diisocyanate compound) or in the product formed in the reaction of the diisocyanate compound with the polyol (e.g., urethane compound with terminal isocyanate groups). The hydroxy acrylate compound reacts with the terminal isocyanate groups to provide terminal acrylate groups to one or more components of the oligomer. In some embodiments, the hydroxy acrylate compound is present in an amount in excess of that required to completely convert the terminal isocyanate groups to terminal acrylate groups. The oligomer includes a single polyether urethane acrylate compound or a combination of two or more polyether urethane acrylate compounds.

The hydroxyacrylate compound is represented by the formula (III):

wherein R is₃Including alkylene groups. R₃The alkylene group of (a) is a linear (e.g., methylene or ethylene), branched (e.g., isopropylidene) or cyclic (e.g., phenylene) group. In some embodiments, the hydroxy acrylate compound comprises a substitution of an ethylenically unsaturated group of an acrylate group. Substituents for the ethylenically unsaturated group include alkyl groups. One example of a hydroxy acrylate compound having a substituted ethylenically unsaturated group is a hydroxy methacrylate compound. The following discussion describes hydroxyacrylate compounds. However, it is to be understood that this discussion applies to substituted hydroxy acrylate compounds, particularly hydroxy methacrylate compounds.

In various embodiments, the hydroxyacrylate compound is a hydroxyalkyl acrylate, such as 2-hydroxyethyl acrylate. The hydroxyacrylate compound may include residual levels or higher levels of water. The presence of water in the hydroxy acrylate compound may facilitate the reaction of the isocyanate groups to reduce the concentration of unreacted isocyanate groups in the final reaction composition. In various embodiments, the water content in the hydroxyacrylate compound is at least 300ppm, or at least 600ppm, or at least 1000ppm, or at least 1500ppm, or at least 2000ppm, or at least 2500 ppm.

In the above exemplary formulae (I), (II) and (III), the group R₁、R₂And R₃Independently all are the same, all are different, or comprise two of the same group and one different group.

The diisocyanate compound, the hydroxyacrylate compound and the polyol are combined and reacted simultaneously or sequentially (in any order). In one embodiment, the oligomer is formed by reacting a diisocyanate compound with a hydroxy acrylate compound, and reacting the resulting product composition with a polyol. In another embodiment, the oligomer is formed by reacting a diisocyanate compound with a polyol compound, and reacting the resulting product composition with a hydroxy acrylate compound.

The oligomer is formed by the reaction of a diisocyanate compound, a hydroxyl acrylate compound and a polyol, wherein the molar ratio of the diisocyanate compound to the hydroxyl acrylate compound to the polyol during the reaction is n: m: p. n, m and p are referred to herein as the moles or molar ratios of diisocyanate, hydroxyacrylate and polyol, respectively. The molar numbers n, m and p are positive integers or positive non-integers. In embodiments, when p is 2.0, n is in the range of 3.0 to 5.0, or in the range of 3.2 to 4.8, or in the range of 3.4 to 4.6, or in the range of 3.5 to 4.4, or in the range of 3.6 to 4.2, or in the range of 3.7 to 4.0; and m is in the range of 1.5 to 4.0, or in the range of 1.6 to 3.6, or in the range of 1.7 to 3.2, or in the range of 1.8 to 2.8, or in the range of 1.9 to 2.4. For p values other than 2.0, the molar ratio n: m: p is scaled. For example, the molar ratio n: m: p ═ 4.0:3.0:2.0 is equal to the molar ratio n: m: p ═ 2.0:1.5: 1.0.

The number of moles m may be selected to provide an amount of the hydroxyacrylate compound that is compatible with the unreacted monomer present in the product compositionThe isocyanate groups are stoichiometrically reacted and the product composition is formed by reacting a diisocyanate compound used to form the oligomer and a polyol. The isocyanate group may be present in an unreacted diisocyanate compound (unreacted starting material) or in an isocyanate terminated urethane compound formed in the reaction of a diisocyanate compound with a polyol. Alternatively, the number of moles m may be selected to provide an amount of the hydroxy acrylate compound in excess of that stoichiometrically required to react with any unreacted isocyanate groups present in the product composition formed from the reaction of the diisocyanate compound and the polyol. The hydroxy acrylate compound is added as a single aliquot or as multiple aliquots. In one embodiment, an initial aliquot of the hydroxyacrylate is included in the reaction mixture used to form the oligomer, and the resulting product composition can be tested for the presence of unreacted isocyanate groups (e.g., using FTIR spectroscopy to detect the presence of isocyanate groups). Additional aliquots of the hydroxyacrylate compound may be added to the product composition to stoichiometrically react with unreacted isocyanate groups [ e.g., FTIR spectroscopy is used to monitor the characteristic frequency of the isocyanate (e.g., at 2260 cm) as the isocyanate groups are converted by the hydroxyacrylate compound^-1To 2270cm^-1Of (a) is reduced]. In an alternative embodiment, an aliquot of the hydroxy acrylate compound is added in excess of the amount stoichiometrically required to react with unreacted isocyanate groups. As described more fully below, for a given p-value, the ratio of moles m to moles n affects the relative proportion of polyether urethane diacrylate compound to binary addition compound in the oligomer, and differences in the relative proportions of polyether urethane diacrylate compound to binary addition compound result in differences in the tear strength and/or critical stress of a coating formed from the oligomer.

In one embodiment, the oligomer is formed from a reaction mixture comprising 4, 4' -methylenebis (cyclohexyl isocyanate), 2-hydroxyethyl acrylate, and polypropylene glycol in a molar ratio n: m: p as defined above, wherein the polypropylene glycol has a number average molecular weight in the range of 2500g/mol to 6500g/mol, or in the range of 3000g/mol to 6000g/mol, or in the range of 3500g/mol to 5500 g/mol.

The oligomer comprises two components. The first component is a polyether urethane diacrylate compound having the formula (IV):

and the second component is a binary addition compound having the formula (V):

wherein the radical R₁、R₂、R₃And the integer x is as described above, y is a positive integer, and it is understood that the group R in formulae (IV) and (V)₁And the group R in the formula (I)₁Same, group R in formula (IV)₂And the group R in the formula (II)₂Identical, and the radicals R in the formulae (IV) and (V)₃And the group R in the formula (III)₃The same is true. The binary addition compound corresponds to a compound formed by the reaction of both terminal isocyanate groups of the diisocyanate compound of formula (I) with the hydroxy acrylate compound of formula (II), wherein the diisocyanate compound has not undergone the reaction with the polyol of formula (II).

The binary addition compound is formed from the reaction of a diisocyanate compound with a hydroxy acrylate compound during the reaction to form the oligomer. Alternatively, the binary addition compound is formed separately from the reaction used to form the oligomer and is added to the product of the reaction used to form the polyether urethane diacrylate compound, or it is added to a purified form of the polyether urethane diacrylate compound. The hydroxyl groups in the hydroxy acrylate compound react with the isocyanate groups in the diisocyanate compound to provide terminal acrylate groups. The reaction occurs on each isocyanate group of the diisocyanate compound to form a binary addition compound. The binary addition compound is present in the oligomer in an amount of at least 1.0 wt.%, or at least 1.5 wt.%, or at least 2.0 wt.%, or at least 2.25 wt.%, or at least 2.5 wt.%, or at least 3.0 wt.%, or at least 3.5 wt.%, or at least 4.0 wt.%, or at least 4.5 wt.%, or at least 5.0 wt.%, or at least 7.0 wt.%, or at least 9.0 wt.%, or in the range of 1.0 wt.% to 10.0 wt.%, or in the range of 2.0 wt.% to 9.0 wt.%, or in the range of 2.5 wt.% to 6.0 wt.%, or in the range of 3.0 wt.% to 8.0 wt.%, or in the range of 3.0 wt.% to 5.0 wt.%, or in the range of 3.0 wt.% to 5.5 wt.%, or in the range of 3.5 wt.% to 5.0 wt.%, or in the range of 3.5 wt.% to 7.0 wt.%. It should be noted that the concentration of the binary adduct is expressed in terms of wt.% of oligomer rather than in terms of wt.% of the coating composition.

An exemplary reaction for synthesizing oligomers according to the present disclosure includes a diisocyanate compound (4, 4' -methylenebis (cyclohexyl isocyanate), also referred to herein as H12MDI) and a polyol (M)_nAbout 4000g/mol of polypropylene glycol, also referred to herein as PPG4000), to form a polyether urethane diisocyanate compound having the formula (VI):

H12MDI～PPG4000～H12MDI～PPG4000～H12MDI (VI)

wherein "-" represents a urethane linkage formed by the reaction of a terminal isocyanate group of H12MDI with a terminal alcohol group of PPG4000, and-H12 MDI, -H12 MDI-and-PPG 4000-refer to the residues of H12MDI and PPG4000 remaining after the reaction; and M_nRefers to the number average molecular weight. The polyether urethane diisocyanate compound has repeating units of the types (H12 MDI-PPG 4000) to (1). The particular polyether urethane diisocyanate shown includes two PPG4000 units.The reaction may also provide a product having one PPG4000 cell, or three or more PPG4000 cells. The polyether urethane diisocyanate and any unreacted H12MDI include terminal isocyanate groups. In accordance with the present disclosure, a hydroxy acrylate compound (e.g., 2-hydroxyethyl acrylate, which is referred to herein as HEA) is included in the reaction with the terminal isocyanate group to convert it to a terminal acrylate group. Converting the terminal isocyanate group to a terminal acrylate group serves to quench the isocyanate group. The amount of HEA included in the reaction can be an amount estimated to react stoichiometrically with the expected concentration of unreacted isocyanate groups, or an amount in excess of the expected stoichiometry. The reaction of HEA with the polyether urethane diisocyanate compound forms a polyether urethane acrylate compound having the formula (VII):

HEA～H12MDI～PPG4000～H12MDI～PPG4000～H12MDI (VII)

and/or a polyether urethane diacrylate compound having the formula (VIII):

HEA～H12MDI～PPG4000～H12MDI～PPG4000～H12MDI～HEA (VIII)

and the reaction of HEA with unreacted H12MDI forms a binary addition compound having the formula (IX):

HEA～H12MDI～HEA (IX)

wherein-represents a carbamate linkage, and-HEA represents the remaining HEA residue after reaction to form a carbamate linkage (consistent with formulas (IV) and (V)). The combination of polyether urethane diacrylate compound and the binary addition compound in the product composition constitutes the oligomer of the present disclosure. As described more fully below, when one or more oligomers are used in the coating composition, a coating with improved tear strength and critical stress characteristics is obtained. In particular, oligomers with a high proportion of binary addition compounds have been shown to give coatings with high tear strength and/or high critical stress values.

Although described with respect to an illustrative combination of H12MDI, HEA, and PPG4000, the above-described reaction may be generalized to any combination of diisocyanate compounds, hydroxyacrylate compounds, and polyols, wherein the hydroxyacrylate compounds react with terminal isocyanate groups to form terminal acrylate groups, and wherein urethane linkages are formed from isocyanate groups reacting with alcoholic hydroxyl groups of a polyol or hydroxyacrylate compound.

The oligomer includes a compound that is a polyether urethane diacrylate compound having the formula (X):

(Hydroxyacrylates) - (diisocyanates-polyols)_xDiisocyanate (hydroxyacrylate) (X)

And includes a compound that is a binary addition compound having the formula (XI):

(Hydroxyacrylate) to diisocyanates to (Hydroxyacrylate) (XI)

Wherein the relative proportions of the diisocyanate compound, the hydroxyacrylate compound and the polyol used in the oligomer-forming reaction correspond to the molar numbers n, m and p disclosed above.

The compounds represented by formulae (I) and (II) above, for example, are reacted to form polyether urethane diisocyanate compounds represented by formula (XII):

wherein y is the same as y in formula (IV) and is 1, or 2, or 3 or 4 or greater; and x is determined by the number of repeating units of the polyol (as described above).

Further reaction of the polyether urethane isocyanate of formula (VI) with the hydroxy acrylate of formula (III) provides a polyether urethane diacrylate compound represented by formula (IV) described above, which is repeated below:

wherein y is 1, or 2, or 3 or 4 or greater; and x is determined by the number of repeating units of the polyol (as described above).

In one embodiment, the reaction between the diisocyanate compound, the hydroxy acrylate compound and the polyol results in a series of polyether urethane diacrylate compounds, the y of which is different such that the average value of y in the distribution of compounds present in the final reaction mixture is a non-integer number. In one embodiment, the average value of y in the polyether urethane diisocyanates and polyether urethane diacrylates of formulae (VI) and (IV) corresponds to p or p-1 (wherein p is as defined above). In one embodiment, the group R in the polyether urethane diisocyanates and polyether urethane diacrylates of formulae (XII) and (IV)₁The average number of occurrences corresponds to n (where n is as defined above).

The relative proportion of polyether urethane diacrylate to the binary addition compound produced in the reaction is controlled by varying the molar ratio of the moles n, m and p. For the sake of explanation, consider the case where p is 2.0. Within the theoretical limits of complete reaction, two equivalents of p of polyol will react with three equivalents of n of diisocyanate to form a compound of formula (VI) where y is 2. This compound comprises two terminal isocyanate groups which, in the theoretical limit, can be quenched by the subsequent addition of two equivalents m of a hydroxy acrylate compound to form the corresponding polyether urethane diacrylate compound (IV) (where y ═ 2). The theoretical molar ratio n: m: p is defined for this case to be 3.0:2.0: 2.0.

Within the above illustrative theoretical limits, the reaction of diisocyanate, hydroxyl acrylate and polyol in the theoretical molar ratio n: m: p ═ 3.0:2.0:2.0 provides a polyether urethane diacrylate compound of formula (IV) wherein y ═ 2, and no binary addition compounds are formed. Variation of the number of moles n, m and p provides control over the relative proportions of polyether urethane diacrylate and binary adduct formed in the reaction. For example, increasing the number of moles n relative to the number of moles m or the number of moles p can increase the amount of binary addition compound formed in the reaction. The diisocyanate compound, the hydroxyacrylate compound and the polyol compound are reacted in a molar ratio n: m: p, for example, where n is in the range of 3.0 to 5.0, m is in the range of ± 15% of 2n-4, or in the range of ± 10% of 2n-4, or in the range of ± 5% of 2n-4, and p is 2.0, which results in an amount of the bis-adduct compound in the oligomer sufficient to achieve the preferred primary coating properties. For example, an embodiment where n is 4.0, m is within ± 15% of 2n-4, and p is 2.0 means n is 4.0, m is within ± 15% of 4, and p is 2.0, which means n is 4.0, m is in the range of 3.4 to 4.6, and p is 2.0.

By varying the number of moles n, m and p, variations in the relative proportions of the binary adduct and the polyether urethane diacrylate are obtained and by such variations, the young's modulus, in situ modulus, tear strength, critical stress, tensile toughness and other mechanical properties of the coating formed from the oligomer-containing coating composition can be precisely controlled. In one embodiment, control of properties may be achieved by varying the number of units of the polyol in the polyether urethane diacrylate compound (e.g., p 2.0 versus p 3.0 versus p 4.0). In another embodiment, control of tear strength, tensile toughness, and other mechanical properties is achieved by varying the ratio of polyether urethane diacrylate compound to the binary addition compound. For a given number of polyol units of polyether urethane compound, oligomers with variable proportions of binary addition compounds can be prepared. The variation in the ratio of the binary addition compounds can be finely controlled to provide oligomers based on polyether urethane diacrylate compounds with a fixed number of polyol units, thereby providing coatings that provide precise or targeted values of tear strength, critical stress, tensile toughness, or other mechanical properties.

When a primary coating composition is used that includes an oligomer and the oligomer includes a polyether urethane acrylate compound represented by formula (IV) and a binary addition compound represented by formula (V), wherein the concentration of the binary addition compound in the oligomer is at least 1.0 wt.%, or at least 1.5 wt.%, or at least 2.0 wt.%, or at least 2.25 wt.%, or at least 2.5 wt.%, or at least 3.0 wt.%, or at least 3.5 wt.%, or at least 4.0 wt.%, or at least 4.5 wt.%, or at least 5.0 wt.%, or at least 7.0 wt.%, or at least 9.0 wt.%, or in the range of 1.0 wt.% to 10.0 wt.%, or in the range of 2.0 wt.% to 9.0 wt.%, or in the range of 3.0 wt.% to 8.0 wt.%, or in the range of 3.5 wt.% to 7.0 wt.%, or in the range of 2.5 wt.% to 6.0 wt.%, or in the range of 3.0 wt.% to 5.5 wt.%, or in the range of 3.5 wt.% to 5.0 wt.%, improved primary coatings for optical fibers are obtained. It should be noted that the concentration of the binary adduct is expressed in terms of wt.% of oligomer rather than in terms of wt.% of the coating composition. In one embodiment, the concentration of the bis-adduct is increased by varying the molar ratio of diisocyanate to hydroxyacrylate to polyol, n: m: p. In one aspect, the diisocyanate-rich molar ratio n: m: p relative to the polyol promotes the formation of a bis-adduct.

In the above exemplary stoichiometric ratio n: m: p ═ 3:2:2, the reaction proceeds with p equivalents of polyol, n ═ p +1 equivalents of diisocyanate and 2 equivalents of hydroxyacrylate. If the number of moles n exceeds p +1, the diisocyanate compound is present in excess relative to the amount of polyol compound required to form the polyether urethane acrylate of formula (IV). The presence of excess diisocyanate shifts the distribution of the reaction products towards the formation of the reinforcing binary addition compound.

The amount of the hydroxy acrylate may also be increased in order to promote the formation of the diadduct from excess diisocyanate compound. For each equivalent of diisocyanate above the stoichiometric mole number n ═ p +1, two equivalents of hydroxyacrylate are required to form the binary addition compound. In any case where the number of moles p (polyol) is arbitrary, the stoichiometric number of moles n (diisocyanate) and m (hydroxyacrylate) are p +1 and 2, respectively. As the number of moles n increases above stoichiometric, the equivalents of the hydroxy acrylate required to fully react the excess diisocyanate to form the di-adduct can be expressed as m 2+2[ n- (p +1) ], where the first term "2" represents the equivalents of the hydroxy acrylate required to terminate the polyether urethane acrylate compound (compound of formula (V)) and the term 2[ n- (p +1) ] represents the equivalents of the hydroxy acrylate required to convert the excess starting diisocyanate to the di-adduct. If the actual number of moles m is less than the equivalent number, the available hydroxy acrylates react with the isocyanate groups present on the oligomer or with free diisocyanate molecules to form terminal acrylate groups. The relative kinetics of these two reaction pathways determine the relative amounts of polyether urethane diacrylate and the binary adduct formed and the deficiency of the hydroxy acrylate relative to the amount required to quench all unreacted isocyanate groups can be controlled to further affect the relative proportions of polyether urethane diacrylate and binary adduct formed in the reaction.

In some embodiments, the reacting comprises heating a reaction composition formed from a diisocyanate compound, a hydroxyacrylate compound, and a polyol. The heating promotes the conversion of the terminal isocyanate groups to terminal acrylate groups by reaction of the hydroxy acrylate compound with the terminal isocyanate groups. In various embodiments, the hydroxyacrylate compound is present in excess in the initial reaction mixture and/or otherwise obtained or added as unreacted form to effectively convert the terminal isocyanate groups to terminal acrylate groups. The heating occurs as follows: heating at a temperature above 40 ℃ for at least 12 hours, or at a temperature above 40 ℃ for at least 18 hours, or at a temperature above 40 ℃ for at least 24 hours, or at a temperature above 50 ℃ for at least 12 hours, or at a temperature above 50 ℃ for at least 18 hours, or at a temperature above 50 ℃ for at least 24 hours, or at a temperature above 60 ℃ for at least 12 hours, or at a temperature above 60 ℃ for at least 18 hours, or at a temperature above 60 ℃ for at least 24 hours.

In one embodiment, the conversion of terminal isocyanate groups or initial diisocyanate compounds (unreacted initial amount or amount present in excess) on the polyether urethane diacrylate compound to terminal acrylate groups is facilitated by adding a supplemental amount of a hydroxy acrylate compound to the reaction mixture. As mentioned above, the amount of the hydroxy acrylate compound required to quench (neutralize) the terminal isocyanate groups may deviate from the theoretical equivalent number, for example, because the reaction is incomplete or the relative proportion of polyether urethane diacrylate compound to the binary addition compound needs to be controlled. As noted above, once the reaction has progressed to completion or to other endpoints, it is preferred to quench (neutralize) residual isocyanate groups to provide a stable reaction product. In one embodiment, to accomplish this, a supplemental amount of a hydroxy acrylate is added.

In one embodiment, the amount of supplemental hydroxyacrylate compound is an amount other than that included during the initial reaction. Monitoring the presence of terminal isocyanate groups at any stage of the reaction, e.g., by FTIR spectroscopy (e.g., using 2265 cm)^-1Nearby isocyanate characteristic stretch mode) and adding supplemental hydroxy acrylate compound as needed until the strength of the characteristic stretch mode of the isocyanate groups is negligible or below a predetermined threshold. In one embodiment, the supplemental hydroxy acrylate compound is added in excess of the amount required to completely convert the terminal isocyanate groups to terminal acrylate groups. In various embodiments, the supplemental hydroxy acrylate compound is included in the initial reaction mixture (as a higher amount than the theoretical amount expected from the molar amounts of diisocyanate and polyol), added as the reaction progresses, and/or added after the reaction of the diisocyanate and polyol compounds has occurred to completion or a predetermined extent.

The amount of the hydroxy acrylate compound exceeding the amount required for complete conversion of the isocyanate groups refers herein to the excess amount of the hydroxy acrylate compound. When added, the excess amount of the hydroxy acrylate compound is at least 20% of the amount of supplemental hydroxy acrylate compound required to completely convert the terminal isocyanate group to a terminal acrylate group, or at least 40% of the amount of supplemental hydroxy acrylate compound required to completely convert the terminal isocyanate group to a terminal acrylate group, or at least 60% of the amount of supplemental hydroxy acrylate compound required to completely convert the terminal isocyanate group to a terminal acrylate group, or at least 90% of the amount of supplemental hydroxy acrylate compound required to completely convert the terminal isocyanate group to a terminal acrylate group.

In one embodiment, the amount of supplemental hydroxy acrylate compound may be sufficient to completely or near completely quench the residual isocyanate groups present in the oligomers formed in the reaction. Quenching the isocyanate groups is desirable because isocyanate groups are relatively unstable over time and often undergo reaction. This reaction changes the characteristics of the reactive composition or oligomer and may result in non-uniformity of the coating formed thereby. It is expected that reaction compositions and products formed from starting diisocyanates and polyol compounds that are free of residual isocyanate groups will have greater stability and predictability of characteristics.

The oligomers of the primary coating composition include the polyether urethane diacrylate compound and the binary addition compound as described above. In some embodiments, the oligomer comprises two or more polyether urethane diacrylate compounds and/or two or more binary addition compounds. The oligomer content of the primary coating composition comprises the combined amount of one or more polyether urethane diacrylate compounds and one or more binary addition compounds and is greater than 20 wt%, or greater than 30 wt%, or greater than 40 wt%, or in the range of 20 wt% to 80 wt%, or in the range of 30 wt% to 70 wt%, or in the range of 40 wt% to 60 wt%, wherein the concentration of the binary addition compounds in the oligomer content is as described above.

The curable primary coating composition also includes one or more monomers. The one or more monomers are selected to be compatible with the oligomer, to control the viscosity of the primary coating composition to facilitate processing, and/or to affect the physical or chemical properties of a coating formed as a cured product of the primary coating composition. The monomers include radiation curable monomers such as ethylenically unsaturated compounds, ethoxylated acrylates, ethoxylated alkylphenol monoacrylates, propylene oxide acrylates, n-propylene oxide acrylates, iso-propylene oxide acrylates, monofunctional aliphatic epoxy acrylates, multifunctional aliphatic epoxy acrylates, and combinations thereof.

Representative radiation curable ethylenically unsaturated monomers include alkoxylated monomers having one or more acrylate or methacrylate groups. Alkoxylated monomers are monomers comprising one or more alkyleneoxy groups, wherein the alkyleneoxy groups have the form-O-R-and R is a linear or branched alkylene group. Examples of alkyleneoxy groups include ethyleneoxy (-O-CH)₂-CH₂-) n-propylidene (-O-CH)₂-CH₂-CH₂-) isopropylidene (-O-CH)₂-CH(CH₃) -, or-O-CH (CH)₃)-CH₂-) and the like. The degree of alkoxylation as used herein refers to the number of alkyleneoxy groups in the monomer. In one embodiment, the alkyleneoxy groups are continuously bonded in the monomer.

In some embodiments, the primary coating composition comprises a polymer having the formula R₄—R₅—O—(CH(CH₃)CH₂—O)_q—C(O)CH＝CH₂Wherein R is₄And R₅Is aliphatic, aromatic or a mixture of the two, and q is 1 to 10; or comprises a compound having the formula R₄—O—(CH(CH₃)CH₂—O)_q—C(O)CH＝CH₂Wherein C (O) is carbonyl, R₁Is aliphatic or aromatic and q is 1 to 10.

Representative examples of monomers include: ethylenically unsaturated monomers, such as lauryl acrylate [ e.g., SR335 from Sartomer Company, Inc., AGEFLEX FA12 from BASF and PHOTOMER 4812 from IGM Resins, Inc. ], ethoxylated nonylphenol acrylate (e.g., SR504 from Sartomer Company and PHOTOMER4066 from IGM Resins), caprolactone acrylate [ e.g., SR495 from Sartomer Company and TONE M-100 from Dow Chemical ], phenoxyethyl acrylate (e.g., SR339 from Sartomer Company, AGEFLEX PEA from BASF and PHOTOMER 4035 from IGM Resins), isooctyl acrylate (e.g., SR440 from Sartomer Company and EFAGEFLEX FA8 from BASF), tridecyl acrylate (e.g., AGEFLEX FA from SAGE SR489), and isobornyl acrylate [ e.g., AGEFLEX SR506 from SALPS, AGCPS 506 from SALPS, AGLEX SR489 from SALPS Chemicals, CORPOR, PHOTOMER M-100, SALPS, SAPLEX FA Tetrahydrofurfuryl acrylate (e.g., SR285 from Sartomer), stearyl acrylate (e.g., SR257 from Sartomer), isodecyl acrylate (e.g., SR395 from Sartomer and AGEFLEX FA10 from Pasteur), 2- (2-ethoxyethoxy) ethyl acrylate (e.g., SR256 from Sartomer), epoxy acrylates [ e.g., CN120 from Sartomer and EBECRYL 3201 and 3604 from Satec Industries, Inc. ], lauryloxyglycidyl acrylate (e.g., CN130 from Sartomer) and phenoxyglycidyl acrylate (e.g., CN131 from Sartomer), and combinations thereof.

In some embodiments, the monomer component of the primary coating composition comprises a multifunctional (meth) acrylate. The multifunctional ethylenically unsaturated monomer includes a multifunctional acrylate monomer and a multifunctional methacrylate monomer. A multifunctional acrylate is an acrylate having two or more polymerizable acrylate moieties per molecule, or three or more polymerizable acrylate moieties per molecule. Examples of multifunctional (meth) acrylates include dipentaerythritol monohydroxypentaacrylate (e.g., PHOTOMER4399 available from IGM resins, Inc.); alkoxylated and non-alkoxylated methylol propane polyacrylates such as trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate (e.g., PHOTOMER4355 from IGM resins); alkoxylated glycerol triacrylates, e.g., propoxylated glycerol triacrylates having a degree of propoxylation of 3 or greater (e.g., PHOTOMER 4096 from IGM resins, Inc.); and alkoxylated and non-alkoxylated erythritol polyacrylates such as pentaerythritol tetraacrylate [ e.g., SR295 available from sartomer (west chester, pa) ]; ethoxylated pentaerythritol tetraacrylate (e.g., SR494 from sartomer company); dipentaerythritol pentaacrylate (e.g., PHOTOMER4399 from IGM resins and SR399 from Saedoma); tripropylene glycol diacrylate; propoxylated hexanediol diacrylate; tetrapropylene glycol diacrylate; pentapropylene glycol diacrylate, methacrylate analogs of the foregoing, and combinations thereof.

In some embodiments, the primary coating composition includes an N-vinyl amide monomer, for example, N-vinyl lactam, or N-vinyl pyrrolidone, or N-vinyl caprolactam, wherein the N-vinyl amide monomer is present in the coating composition at a concentration of: greater than 1.0 wt%, or greater than 2.0 wt%, or greater than 3.0 wt%, or in the range of 1.0 wt% to 15.0 wt%, or in the range of 2.0 wt% to 10.0 wt%, or in the range of 3.0 wt% to 8.0 wt%.

In one embodiment, the primary coating composition comprises from 15 wt% to 90 wt%, or from 30 wt% to 75 wt%, or from 40 wt% to 65 wt% of one or more monofunctional acrylate or methacrylate monomers. In another embodiment, the primary coating composition may comprise from 5 wt% to 40 wt%, or from 10 wt% to 30 wt% of one or more monofunctional aliphatic epoxy acrylate or methacrylate monomers.

In one embodiment, the monomer component of the primary coating composition comprises a hydroxy-functional monomer. Hydroxy functional monomers are monomers that have pendant hydroxy moieties in addition to other reactive functional groups, such as (meth) acrylates. Examples of hydroxyl functional monomers containing pendant hydroxyl groups include: caprolactone acrylate (available as TONE M-100 from Dow chemical); poly (alkylene glycol) mono (meth) acrylates such as poly (ethylene glycol) monoacrylate, poly (propylene glycol) monoacrylate, and poly (tetramethylene glycol) monoacrylate [ each available from monomeric Polymer & dejac Labs (Monomer, Polymer & Dajac Labs) ]; 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate [ each available from Aldrich (Aldrich) ].

In one embodiment, the hydroxy-functional monomer is present in an amount sufficient to increase the adhesion of the primary coating to the optical fiber. The hydroxy-functional monomer is present in the coating composition in an amount of about 0.1% to about 25% by weight, or about 5% to about 8% by weight. The use of a hydroxy-functional monomer can reduce the amount of adhesion promoter necessary to adequately adhere the primary coating to the optical fiber. The use of hydroxy-functional monomers also tends to increase the hydrophilicity of the coating. Hydroxy functional monomers are described in more detail in U.S. patent No. 6,563,996, the disclosure of which is incorporated herein by reference in its entirety.

In various embodiments, the total monomer content of the primary coating composition is from about 15 wt% to about 90 wt%, or from about 30 wt% to about 75 wt%, or from about 40 wt% to about 65 wt%.

In addition to the curable monomers and curable oligomers, the curable primary coating composition also includes a polymerization initiator. The polymerization initiator facilitates initiation of a polymerization process associated with curing of the coating composition to form a coating. Polymerization initiators include thermal initiators, chemical initiators, electron beam initiators, and photoinitiators. The photoinitiator comprises a ketone photoinitiator and/or a phosphine oxide photoinitiator. When used in the curing of coating compositions, the photoinitiator is present in an amount sufficient to effect rapid radiation cure.

Representative photoinitiators include 1-hydroxycyclohexyl phenyl ketone (e.g., IRGACURE 184 available from basf); bis (2, 6-dimethoxybenzoyl) -2,4, 4-trimethylpentylphosphine oxide (e.g., a commercial blend of IRGACURE 1800, 1850 and 1700 available from basf); 2, 2-dimethoxy-2-phenylacetophenone (e.g., IRGACURE 651 from basf); bis (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide (IRGACURE 819); (2,4, 6-trimethylbenzoyl) diphenylphosphine oxide [ LUCIRIN TPO available from BASF corporation (Munich, Germany) ]; ethoxy (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide (LUCIRIN TPO-L from BASF corporation) and combinations thereof.

The coating composition includes a single photoinitiator or a combination of two or more photoinitiators. The total photoinitiator content of the coating composition is up to about 10 wt%, or between about 0.5 wt% and about 6 wt%.

The curable primary coating composition optionally includes one or more additives. Additives include adhesion promoters, enhancers, antioxidants, catalysts, stabilizers, brighteners, property enhancers, amine synergists, waxes, lubricants, and/or slip agents. Some additives may be used to control the polymerization process, thereby affecting the physical properties (e.g., modulus, glass transition temperature) of the polymerized product formed from the coating composition. Other additives affect the integrity of the cured product of the primary coating composition (e.g., protect it from depolymerization or oxidative degradation).

Adhesion promoters are compounds that promote the adhesion of a primary coating and/or a primary composition to glass (e.g., the cladding portion of a glass optical fiber). Suitable adhesion promoters include alkoxysilanes, mercapto-functional silanes, organotitanates, and zirconates. Representative adhesion promoters include mercaptoalkylsilanes or mercaptoalkoxysilanes such as 3-mercaptopropyl-trialkoxysilane [ e.g., 3-mercaptopropyl-trimethoxysilane, available from gel est, litton, pa ]; bis (trialkoxysilyl-ethyl) benzene; acryloxypropyltrialkoxysilanes (e.g., (3-acryloxypropyl) -trimethoxysilane, available from GELEST corporation), methacryloxypropyltrialkoxysilanes, vinyltrialkoxysilanes, bis (trialkoxysilylethyl) hexane, allyltrialkoxysilanes, styrylethyltrialkoxysilanes, and bis (trimethoxysilylethyl) benzene [ available from United Chemical Technologies, Inc., of Bristol, Pa.); see U.S. patent No. 6,316,516, the disclosure of which is incorporated herein by reference in its entirety.

The adhesion promoter is present in the primary coating composition in an amount of between 0.02 wt% and 10.0 wt%, or between 0.05 wt% and 4.0 wt%, or between 0.1 wt% and 3.0 wt%, or between 0.1 wt% and 2.0 wt%, or between 0.1 wt% and 1.0 wt%, or between 0.5 wt% and 4.0 wt%, or between 0.5 wt% and 3.0 wt%, or between 0.5 wt% and 2.0 wt%, or between 0.5 wt% and 1.0 wt%.

A representative antioxidant is thiodiethylene bis [3- (3, 5-di-tert-butyl) -4-hydroxyphenyl) propionate ] (e.g., IRGANOX 1035, available from BASF corporation). In some aspects, the antioxidant is present in the coating composition in an amount greater than 0.25 wt.%, or greater than 0.50 wt.%, or greater than 0.75 wt.%, or greater than 1.0 wt.%, or in an amount in the range of 0.25 wt.% to 3.0 wt.%, or in an amount in the range of 0.50 wt.% to 2.0 wt.%, or in an amount in the range of 0.75 wt.% to 1.5 wt.%.

Representative brighteners include TINOPAL OB (available from BASF corporation); blankophor KLA [ available from Bayer (Bayer) ]; a bis-benzoxazole compound; a phenylcoumarin compound; and bis (styryl) biphenyl compounds. In one embodiment, the brightener is present in the coating composition at a concentration of 0.005 wt.% to 0.3 wt.%.

Representative amine synergists include triethanolamine; 1, 4-diazabicyclo [2.2.2] octane (DABCO), triethylamine, and methyldiethanolamine. In one embodiment, the amine synergist is present at a concentration of 0.02 wt% to 0.5 wt%.

Primary coating-property. Relevant properties of the primary coating include radius, thickness, young's modulus and in situ modulus.

Radius of primary coatingr₅Less than or equal to 85.0 μm, or less than or equal to 80.0 μm, or less than or equal to 75.0 μm, or less than or equal to 70.0 μm.

In order to facilitate the reduction of the diameter of the optical fiber, it is preferable to make the thickness r of the primary coating layer₅–r₄And (4) minimizing. Thickness r of primary coating₅–r₄Less than or equal to 25.0 μm, or less than or equal to 20.0 μm, or less than or equal to 15.0 μm, or less than or equal to 10.0 μm, or in the range of 5.0 μm to 25.0 μm, or in the range of 8.0 μm to 20.0 μm, or in the range of 10.0 μm to 17.0 μm.

To help effectively buffer stress and protect the glass fiber, the primary coating preferably has a low young's modulus and/or a low in-situ modulus. The primary coating has a Young's modulus of less than or equal to 0.7MPa, or less than or equal to 0.6MPa, or less than or equal to 0.5MPa, or less than or equal to 0.4MPa, or in the range of 0.2MPa to 0.7MPa, or in the range of 0.3MPa to 0.6 MPa. The primary coating has an in situ modulus of less than or equal to 0.25MPa, or less than or equal to 0.20MPa, or less than or equal to 0.15MPa, or less than or equal to 0.10MPa, or in the range of 0.05MPa to 0.25MPa, or in the range of 0.10MPa to 0.20 MPa.

Secondary coating-composition. The secondary coating is the cured product of a curable secondary coating composition comprising monomers, photoinitiators, optional oligomers, and optional additives. The present disclosure describes optional oligomers for use in the radiation curable secondary coating composition, a cured product of the radiation curable secondary coating composition, an optical fiber coated with the radiation curable secondary coating composition, and an optical fiber coated with the cured product of the radiation curable secondary coating composition.

The secondary coating is formed as a cured product of a radiation curable secondary coating composition that includes a monomer component having one or more monomers. The monomer preferably comprises an ethylenically unsaturated compound. The one or more monomers may be present in an amount of greater than or equal to 50 wt%, or in an amount of about 60 wt% to about 99 wt%, or in an amount of about 75 wt% to about 99 wt%, or in an amount of about 80 wt% to about 99 wt%, or in an amount of about 85 wt% to about 99 wt%. In one embodiment, the secondary coating is a radiation cured product of a secondary coating composition comprising a urethane acrylate monomer.

The monomers include functional groups that are polymerizable groups and/or groups that promote or enable crosslinking. The monomer is a monofunctional monomer or a multifunctional monomer. In combinations having two or more monomers, the monomers of the composition are monofunctional monomers, multifunctional monomers, or a combination of monofunctional monomers and multifunctional monomers. In one embodiment, the monomer component of the curable secondary coating composition includes an ethylenically unsaturated monomer. Suitable functional groups of the ethylenically unsaturated monomers include, but are not limited to, (meth) acrylates, acrylamides, N-vinyl amides, styrenes, vinyl ethers, vinyl esters, acid esters, and combinations thereof.

In one embodiment, the monomer component of the curable secondary coating composition includes an ethylenically unsaturated monomer. The monomers include functional groups that are polymerizable groups and/or groups that promote or enable crosslinking. The monomer is a monofunctional monomer or a multifunctional monomer. In combinations having two or more monomers, the monomers of the composition are monofunctional monomers, multifunctional monomers, or a combination of monofunctional monomers and multifunctional monomers. Suitable functional groups of the ethylenically unsaturated monomers include, but are not limited to, (meth) acrylates, acrylamides, N-vinyl amides, styrenes, vinyl ethers, vinyl esters, acid esters, and combinations thereof.

Exemplary monofunctional ethylenically unsaturated monomers of the curable secondary coating composition include, but are not limited to, hydroxyalkyl acrylates, such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate; long-chain and short-chain alkyl acrylates, such as methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, pentyl acrylate, isobutyl acrylate, tert-butyl acrylate, pentyl acrylate, isopentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, isodecyl acrylate, undecyl acrylate, dodecyl acrylate, lauryl acrylate, stearyl acrylate, and stearyl acrylate; aminoalkyl acrylates, such as dimethylaminoethyl acrylate, diethylaminoethyl acrylate, and 7-amino-3, 7-dimethyloctyl acrylate; alkoxyalkyl acrylates, such as butoxyethyl acrylate, phenoxyethyl acrylate [ e.g., SR339 from Sartomer Company, Inc. ] and ethoxyethoxyethyl acrylate; monocyclic and polycyclic cyclic aromatic or non-aromatic acrylates, such as cyclohexyl acrylate, benzyl acrylate, dicyclopentadiene acrylate, dicyclopentyl acrylate, tricyclodecanyl acrylate, bornyl acrylate (bomyl) ester, isobornyl acrylate (e.g. SR423 from sartomer), tetrahydrofurfuryl acrylate (e.g. SR285 from sartomer), caprolactone acrylate (e.g. SR495 from sartomer) and acryloyl morpholine; alcohol-based acrylates, such as polyethylene glycol monoacrylate, polypropylene glycol monoacrylate, methoxy ethylene glycol acrylate, methoxy polypropylene glycol acrylate, methoxy polyethylene glycol acrylate, ethoxy diethylene glycol acrylate, and various alkoxylated alkylphenol acrylates, such as ethoxylated (4) nonylphenol acrylate [ e.g., Photomer4066 from IGM Resins (IGM Resins) ]; acrylamides such as diacetone acrylamide, isobutoxy methacrylamide, N' -dimethyl-aminopropyl acrylamide, N-dimethylacrylamide, N-diethylacrylamide and tert-octylacrylamide; vinyl compounds such as N-vinylpyrrolidone and N-vinylcaprolactam; and acidic esters such as maleic acid esters and fumaric acid esters. For the long and short chain alkyl acrylates listed above, the short chain alkyl acrylate is an alkyl group having 6 or less carbons and the long chain alkyl acrylate is an alkyl group having 7 or more carbons.

Representative radiation curable ethylenically unsaturated monomers include alkoxylated monomers having one or more acrylate or methacrylate groups. Alkoxylated monoThe monomer is a monomer comprising one or more alkyleneoxy groups, wherein the alkyleneoxy groups have the form-O-R-, and R is a straight or branched chain hydrocarbon. Examples of alkyleneoxy groups include ethyleneoxy (-O-CH)₂-CH₂-) n-propylidene (-O-CH)₂-CH₂-CH₂-) isopropylidene (-O-CH)₂-CH(CH₃) -) and the like. The degree of alkoxylation as used herein refers to the number of alkyleneoxy groups in the monomer. In one embodiment, the alkyleneoxy groups are continuously bonded in the monomer.

The degree of alkoxylation as used herein refers to the number of alkyleneoxy groups divided by the number of acrylate and methacrylate groups in the monomer molecule. For monofunctional alkoxylated monomers, the degree of alkoxylation corresponds to the number of alkyleneoxy groups in the monomer molecule. In a preferred embodiment, the alkyleneoxy groups of the monofunctional alkoxylated monomer are bonded continuously. For difunctional alkoxylated monomers, the degree of alkoxylation corresponds to half the number of alkyleneoxy groups in the monomer molecule. In a preferred embodiment, the alkyleneoxy groups in the difunctional alkoxylated monomer are bonded in series in each of two groups, wherein the two groups are separated by a chemical linkage and each group comprises half or about half of the number of alkyleneoxy groups in the molecule. For trifunctional alkoxylated monomers, the degree of alkoxylation corresponds to one third of the number of alkyleneoxy groups in the monomer molecule. In a preferred embodiment, the alkyleneoxy groups in the trifunctional alkoxylated monomer are bonded in succession in three groups, wherein the three groups are separated by chemical linkages and each group comprises one third or about one third of the number of alkyleneoxy groups in the molecule.

Representative polyfunctional ethylenically unsaturated monomers of the curable secondary coating composition include, but are not limited to, alkoxylated bisphenol a diacrylates, e.g., ethoxylated bisphenol a diacrylates, and alkoxylated trimethylolpropane triacrylates, e.g., ethoxylated trimethylolpropane triacrylate, and having a degree of alkoxylation of greater than or equal to 2, or greater than or equal to 4, or greater than or equal to 6, or less than 16, or less than 12, or less than 8, or less than 5, or in the range of 2 to 16, or in the range of 2 to 12, or in the range of 2 to 8, or in the range of 2 to 4, or in the range of 3 to 12, or in the range of 3 to 8, or in the range of 3 to 5, or in the range of 4 to 12, or in the range of 4 to 10, or in the range of 4 to 8.

The multifunctional ethylenically unsaturated monomer of the curable secondary coating composition includes, but is not limited to, alkoxylated bisphenol a diacrylate, such as ethoxylated bisphenol a diacrylate, having a degree of alkoxylation of 2 or greater. The monomer component of the secondary coating composition may include ethoxylated bisphenol a diacrylate having a degree of ethoxylation of from 2 to about 30 (e.g., SR349, SR601, and SR602 available from sandomar, west chester, pennsylvania and Photomer 4025 and Photomer 4028 available from IGM resin), or propoxylated bisphenol a diacrylate having a degree of propoxylation of 2 or greater, e.g., from 2 to about 30; alkoxylated and non-alkoxylated methylol propane polyacrylates such as ethoxylated trimethylolpropane triacrylate having a degree of ethoxylation of 3 or greater, for example, 3 to about 30 (e.g., Photomer 4149 by IGM resins and SR499 by sandoma); propoxylated trimethylolpropane triacrylate having a degree of propoxylation of 3 or more, for example 3 to 30 (e.g., Photomer 4072 from IGM resin and SR492 from sartomer); ditrimethylolpropane tetraacrylate (e.g., Photomer4355 from IGM resins); alkoxylated glyceryl triacrylates, e.g., propoxylated glyceryl triacrylates having a degree of propoxylation of 3 or greater (e.g., Photomer 4096 from IGM and SR9020 from sartomer); alkoxylated and non-alkoxylated erythritol polyacrylates such as pentaerythritol tetraacrylate (e.g., SR295 available from sartomer, west chester, pennsylvania), ethoxylated pentaerythritol tetraacrylate (e.g., SR494 from sartomer), and dipentaerythritol pentaacrylate (e.g., Photomer4399 from IGM resins and SR399 from sartomer); isocyanurate polyacrylates formed by reacting a suitable functional isocyanurate with acrylic acid or acryloyl chloride, such as tris- (2-hydroxyethyl) isocyanurate triacrylate (e.g., SR368 from sartomer company) and tris- (2-hydroxyethyl) isocyanurate diacrylate; alkoxylated and non-alkoxylated alcohol polyacrylates such as tricyclodecane dimethanol diacrylate (e.g., CD406 from sartomer company) and ethoxylated polyethylene glycol diacrylate having a degree of ethoxylation of 2 or greater, e.g., about 2 to 30; epoxy acrylate formed by adding acrylate to bisphenol a diglycidyl ether or the like (for example, Photomer3016 from IGM resins); and monocyclic and polycyclic cyclic aromatic or non-aromatic polyacrylates such as dicyclopentadiene diacrylate and dicyclopentane diacrylate.

The polyfunctional ethylenically unsaturated monomer of the curable secondary coating composition comprises an ethoxylated bisphenol a diacrylate having a degree of ethoxylation of from 2 to 16 (e.g., SR349, SR601 and SR602 available from sandomar, west chester, pennsylvania and Photomer 4028 available from IGM resins), or a propoxylated bisphenol a diacrylate having a degree of propoxylation of 2 or greater, e.g., from 2 to 16; alkoxylated and non-alkoxylated methylol propane polyacrylates, such as alkoxylated or ethoxylated trimethylolpropane triacrylates having a degree of alkoxylation or ethoxylation of 2 or greater, for example, 2 to 16 or 3 to 10 (e.g., Photomer 4149 from IGM resins and SR499 from sandoma); propoxylated trimethylolpropane triacrylate having a degree of propoxylation of 2 or greater, for example, 2 to 16 (e.g., Photomer 4072 from IGM resin and SR492 from sartomer); ditrimethylolpropane tetraacrylate (e.g., Photomer4355 from IGM resins); alkoxylated glyceryl triacrylates, e.g., propoxylated glyceryl triacrylates having a degree of propoxylation of 2 or greater, e.g., 2 to 16 (e.g., Photomer 4096 from IGM and SR9020 from sartomer); alkoxylated and non-alkoxylated erythritol polyacrylates such as pentaerythritol tetraacrylate (e.g., SR295 available from sartomer, west chester, pennsylvania), ethoxylated pentaerythritol tetraacrylate (e.g., SR494 from sartomer), and dipentaerythritol pentaacrylate (e.g., Photomer4399 from IGM resins and SR399 from sartomer); isocyanurate polyacrylates formed by reacting a suitable functional isocyanurate with acrylic acid or acryloyl chloride, such as tris- (2-hydroxyethyl) isocyanurate triacrylate (e.g., SR368 from sartomer company) and tris- (2-hydroxyethyl) isocyanurate diacrylate; alkoxylated and non-alkoxylated alcohol polyacrylates such as tricyclodecane dimethanol diacrylate (e.g. CD406 from sartomer company) and ethoxylated polyethylene glycol diacrylates having a degree of ethoxylation of 2 or more, for example from 2 to 16; epoxy acrylate formed by adding acrylate to bisphenol a diglycidyl ether or the like (for example, Photomer3016 from IGM resins); and monocyclic and polycyclic cyclic aromatic or non-aromatic polyacrylates such as dicyclopentadiene diacrylate and dicyclopentane diacrylate.

In some embodiments, the curable secondary coating composition includes a multifunctional monomer having three or more curable functional groups in an amount greater than 2.0 wt.%, or greater than 5.0 wt.%, or greater than 7.5 wt.%, or greater than 10 wt.%, or greater than 15 wt.%, or greater than 20 wt.%, or in the range of 2.0 wt.% to 25 wt.%, or in the range of 5.0 wt.% to 20 wt.%, or in the range of 8.0 wt.% to 15 wt.%. In a preferred embodiment, each of the three or more curable functional groups is an acrylate group.

In some embodiments, the curable secondary coating composition includes a trifunctional monomer in an amount greater than 2.0 wt.%, or greater than 5.0 wt.%, or greater than 7.5 wt.%, or greater than 10 wt.%, or greater than 15 wt.%, or greater than 20 wt.%, or in the range of 2.0 wt.% to 25 wt.%, or in the range of 5.0 wt.% to 20 wt.%, or in the range of 8.0 wt.% to 15 wt.%. In a preferred embodiment, the trifunctional monomer is a triacrylate monomer.

In some embodiments, the curable secondary coating composition includes a difunctional monomer in an amount greater than 55 wt.%, or greater than 60 wt.%, or greater than 65 wt.%, or greater than 70 wt.%, or in the range of 55 wt.% to 80 wt.%, or in the range of 60 wt.% to 75 wt.%, and also includes a trifunctional monomer in an amount in the range of 2.0 wt.% to 25 wt.%, or in the range of 5.0 wt.% to 20 wt.%, or in the range of 8.0 wt.% to 15 wt.%. In a preferred embodiment, the difunctional monomer is a diacrylate monomer and the trifunctional monomer is a triacrylate monomer. Preferred diacrylate monomers include alkoxylated bisphenol A diacrylate. Preferred triacrylate monomers include alkoxylated trimethylolpropane triacrylate and isocyanurate triacrylate. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In some embodiments, the curable secondary coating composition is free of monofunctional monomers and includes difunctional monomers in an amount greater than 55 wt.%, or greater than 60 wt.%, or greater than 65 wt.%, or greater than 70 wt.%, or in a range from 55 wt.% to 80 wt.%, or in a range from 60 wt.% to 75 wt.%, and also includes trifunctional monomers in an amount in a range from 2.0 wt.% to 25 wt.%, or in a range from 5.0 wt.% to 20 wt.%, or in a range from 8.0 wt.% to 15 wt.%. In a preferred embodiment, the difunctional monomer is a diacrylate monomer and the trifunctional monomer is a triacrylate monomer. Preferred diacrylate monomers include alkoxylated bisphenol A diacrylate. Preferred triacrylate monomers include alkoxylated trimethylolpropane triacrylate and isocyanurate triacrylate. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In some embodiments, the curable secondary coating composition includes two or more difunctional monomers in a combined amount greater than 70 wt.%, or greater than 75 wt.%, or greater than 80 wt.%, or greater than 85 wt.%, or in a range from 70 wt.% to 95 wt.%, or in a range from 75 wt.% to 90 wt.%, and further includes a trifunctional monomer in an amount in a range from 2.0 wt.% to 25 wt.%, or in a range from 5.0 wt.% to 20 wt.%, or in a range from 8.0 wt.% to 15 wt.%. In a preferred embodiment, the difunctional monomer is a diacrylate monomer and the trifunctional monomer is a triacrylate monomer. Preferred diacrylate monomers include alkoxylated bisphenol A diacrylate. Preferred triacrylate monomers include alkoxylated trimethylolpropane triacrylate and isocyanurate triacrylate. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In some embodiments, the curable secondary coating composition is free of monofunctional monomers and includes two or more difunctional monomers in a combined amount greater than 70 wt.%, or greater than 75 wt.%, or greater than 80 wt.%, or greater than 85 wt.%, or in a range from 70 wt.% to 95 wt.%, or in a range from 75 wt.% to 90 wt.%, and also includes trifunctional monomers in an amount in a range from 2.0 wt.% to 25 wt.%, or in a range from 5.0 wt.% to 20 wt.%, or in a range from 8.0 wt.% to 15 wt.%. In a preferred embodiment, the difunctional monomer is a diacrylate monomer and the trifunctional monomer is a triacrylate monomer. Preferred diacrylate monomers include alkoxylated bisphenol A diacrylate. Preferred triacrylate monomers include alkoxylated trimethylolpropane triacrylate and isocyanurate triacrylate. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In some embodiments, the curable secondary coating composition includes two or more difunctional monomers in a combined amount greater than 70 wt.%, or greater than 75 wt.%, or greater than 80 wt.%, or greater than 85 wt.%, or in a range from 70 wt.% to 95 wt.%, or in a range from 75 wt.% to 90 wt.%, and also includes two or more trifunctional monomers in a combined amount in a range from 2.0 wt.% to 25 wt.%, or in a range from 5.0 wt.% to 20 wt.%, or in a range from 8.0 wt.% to 15 wt.%. In a preferred embodiment, each of the two or more difunctional monomers is a diacrylate monomer and each of the two or more trifunctional monomers is a triacrylate monomer. Preferred diacrylate monomers include alkoxylated bisphenol A diacrylate. Preferred triacrylate monomers include alkoxylated trimethylolpropane triacrylate and isocyanurate triacrylate. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In some embodiments, the curable secondary coating composition is free of monofunctional monomers and includes two or more difunctional monomers in a combined amount greater than 70 wt.%, or greater than 75 wt.%, or greater than 80 wt.%, or greater than 85 wt.%, or in a range from 70 wt.% to 95 wt.%, or in a range from 75 wt.% to 90 wt.%, and also includes two or more trifunctional monomers in a combined amount in a range from 2.0 wt.% to 25 wt.%, or in a range from 5.0 wt.% to 20 wt.%, or in a range from 8.0 wt.% to 15 wt.%. In a preferred embodiment, each of the difunctional monomers is a diacrylate monomer and each of the trifunctional monomers is a triacrylate monomer. Preferred diacrylate monomers include alkoxylated bisphenol A diacrylate. Preferred triacrylate monomers include alkoxylated trimethylolpropane triacrylate and isocyanurate triacrylate. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

The preferred difunctional monomer is an alkoxylated bisphenol a diacrylate. The alkoxylated bisphenol a diacrylate has the general formula (XIII):

wherein R is₁And R₂Is alkylene, R₁-O and R₂-O is alkyleneoxy, and R₃Is H. Radical R₁、R₂And R₃Any two of which are the same or different. In one embodiment, the group R₁And R₂The same is true. Radical R₁And R₂The number of carbons in each is in the range of 1 to 8, or in the range of 2 to 6, or in the range of 2 to 4. The degree of alkoxylation was 1/2(x + y). The values of x and y may be the same or different. In one embodiment, x and y are the same.

The preferred trifunctional monomer is alkoxylated trimethylolpropane triacrylate. The alkoxylated trimethylolpropane triacrylate has the general formula (XIV):

wherein R is₁And R₂Is alkylene, O-R₁、O-R₂And O-R₃Is an alkyleneoxy group. Radical R₁、R₂And R₃Any two of which are the same or different. In one embodiment, the group R₁、R₂And R₃The same is true. Radical R₁、R₂And R₃The number of carbons in each is in the range of 1 to 8, or in the range of 2 to 6, or in the range of 2 to 4. The degree of alkoxylation was 1/3(x + y + z). Any two of x, y and z may have the same or different values. In one embodiment, x, y and z are the same.

Another preferred trifunctional monomer is tris [ (acryloxy) alkyl ] isocyanurate. Tris [ (acryloxy) alkyl ] isocyanurate is also known as tris (n-hydroxyalkyl) isocyanurate triacrylate. A representative tris [ (acryloxy) alkyl ] isocyanurate is tris (2-hydroxyethyl) isocyanurate triacrylate, having the general formula (XV):

in formula (III), the ethylene group is bonded to (-CH)₂-CH₂-) bonding each acryloxy group to the nitrogen of the isocyanurate ring. In a tri [ (acryloyloxy) alkyl group]In other embodiments of the isocyanurate, an alkylene linkage other than ethylene bonds the acryloxy group to a nitrogen atom of the isocyanurate ring. The alkylene linkages of any two of the three alkylene linkages are the same or different. In one embodiment, the three alkylene linkages are the same. The number of carbons in each alkylene linkage is in the range of 1 to 8, or in the range of 2 to 6, or in the range of 2 to 4.

In one embodiment, the curable secondary composition includes an alkoxylated bisphenol a diacrylate monomer in an amount greater than 55 wt.%, or greater than 60 wt.%, or greater than 65 wt.%, or greater than 70 wt.%, or in a range from 55 wt.% to 80 wt.%, or in a range from 60 wt.% to 75 wt.%, and further includes an alkoxylated trimethylolpropane triacrylate monomer in an amount in a range from 2.0 wt.% to 25 wt.%, or in a range from 5.0 wt.% to 20 wt.%, or in a range from 8.0 wt.% to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In one embodiment, the curable secondary composition includes an alkoxylated bisphenol a diacrylate monomer in an amount greater than 55 wt.%, or greater than 60 wt.%, or greater than 65 wt.%, or greater than 70 wt.%, or in a range from 55 wt.% to 80 wt.%, or in a range from 60 wt.% to 75 wt.%, and further includes an ethoxylated trimethylolpropane triacrylate monomer in an amount in a range from 2.0 wt.% to 25 wt.%, or in a range from 5.0 wt.% to 20 wt.%, or in a range from 8.0 wt.% to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In one embodiment, the curable secondary composition includes ethoxylated bisphenol a diacrylate monomer in an amount greater than 55 wt.%, or greater than 60 wt.%, or greater than 65 wt.%, or greater than 70 wt.%, or in a range from 55 wt.% to 80 wt.%, or in a range from 60 wt.% to 75 wt.%, and further includes alkoxylated trimethylolpropane triacrylate monomer in an amount in a range from 2.0 wt.% to 25 wt.%, or in a range from 5.0 wt.% to 20 wt.%, or in a range from 8.0 wt.% to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In one embodiment, the curable secondary composition includes an ethoxylated bisphenol a diacrylate monomer in an amount greater than 55 wt.%, or greater than 60 wt.%, or greater than 65 wt.%, or greater than 70 wt.%, or in a range from 55 wt.% to 80 wt.%, or in a range from 60 wt.% to 75 wt.%, and further includes an ethoxylated trimethylolpropane triacrylate monomer in an amount in a range from 2.0 wt.% to 25 wt.%, or in a range from 5.0 wt.% to 20 wt.%, or in a range from 8.0 wt.% to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In one embodiment, the curable secondary composition includes an alkoxylated bisphenol a diacrylate monomer in an amount greater than 55 wt.%, or greater than 60 wt.%, or greater than 65 wt.%, or greater than 70 wt.%, or in a range from 55 wt.% to 80 wt.%, or in a range from 60 wt.% to 75 wt.%, and further includes a tris [ (acryloxy) alkyl ] isocyanurate monomer in an amount in a range from 2.0 wt.% to 25 wt.%, or in a range from 5.0 wt.% to 20 wt.%, or in a range from 8.0 wt.% to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In one embodiment, the curable secondary composition includes an ethoxylated bisphenol a diacrylate monomer in an amount greater than 55 wt.%, or greater than 60 wt.%, or greater than 65 wt.%, or greater than 70 wt.%, or in a range from 55 wt.% to 80 wt.%, or in a range from 60 wt.% to 75 wt.%, and further includes a tris [ (acryloxy) alkyl ] isocyanurate monomer in an amount in a range from 2.0 wt.% to 25 wt.%, or in a range from 5.0 wt.% to 20 wt.%, or in a range from 8.0 wt.% to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In one embodiment, the curable secondary composition includes an alkoxylated bisphenol a diacrylate monomer in an amount greater than 55 wt.%, or greater than 60 wt.%, or greater than 65 wt.%, or greater than 70 wt.%, or in a range from 55 wt.% to 80 wt.%, or in a range from 60 wt.% to 75 wt.%, and further includes a tris (2-hydroxyethyl) isocyanurate triacrylate monomer in an amount in a range from 2.0 wt.% to 25 wt.%, or in a range from 5.0 wt.% to 20 wt.%, or in a range from 8.0 wt.% to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In one embodiment, the curable secondary composition includes ethoxylated bisphenol a diacrylate monomer in an amount greater than 55 wt.%, or greater than 60 wt.%, or greater than 65 wt.%, or greater than 70 wt.%, or in a range from 55 wt.% to 80 wt.%, or in a range from 60 wt.% to 75 wt.%, and also includes tris (2-hydroxyethyl) isocyanurate triacrylate monomer in an amount in a range from 2.0 wt.% to 25 wt.%, or in a range from 5.0 wt.% to 20 wt.%, or in a range from 8.0 wt.% to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In one embodiment, the curable secondary composition includes a bisphenol A epoxy diacrylate monomer, in an amount greater than 5.0 wt%, or greater than 10 wt%, or greater than 15 wt%, or in the range of 5.0 wt% to 20 wt%, or in the range of from 8 wt% to 17 wt%, or in the range of from 10 wt% to 15 wt%, and further comprising an alkoxylated bisphenol A diacrylate monomer, in an amount greater than 55 wt%, or greater than 60 wt%, or greater than 65 wt%, or greater than 70 wt%, or in the range of 55 to 80 weight percent, or in the range of 60 to 75 weight percent, and further comprising an alkoxylated trimethylolpropane triacrylate monomer, the amount thereof is in the range of 2.0 to 25 wt.%, or in the range of 5.0 to 20 wt.%, or in the range of 8.0 to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In one embodiment, the curable secondary composition includes a bisphenol A epoxy diacrylate monomer, in an amount greater than 5.0 wt%, or greater than 10 wt%, or greater than 15 wt%, or in the range of 5.0 wt% to 20 wt%, or in the range of from 8 wt% to 17 wt%, or in the range of from 10 wt% to 15 wt%, and further comprising an alkoxylated bisphenol A diacrylate monomer, in an amount greater than 55 wt%, or greater than 60 wt%, or greater than 65 wt%, or greater than 70 wt%, or in the range of 55 to 80 weight percent, or in the range of 60 to 75 weight percent, and further comprising an ethoxylated trimethylolpropane triacrylate monomer, the amount thereof is in the range of 2.0 to 25 wt.%, or in the range of 5.0 to 20 wt.%, or in the range of 8.0 to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In one embodiment, the curable secondary composition includes a bisphenol A epoxy diacrylate monomer, in an amount greater than 5.0 wt%, or greater than 10 wt%, or greater than 15 wt%, or in the range of 5.0 wt% to 20 wt%, or in the range of from 8 wt% to 17 wt%, or in the range of from 10 wt% to 15 wt%, and further comprising an ethoxylated bisphenol A diacrylate monomer, in an amount greater than 55 wt%, or greater than 60 wt%, or greater than 65 wt%, or greater than 70 wt%, or in the range of 55 to 80 weight percent, or in the range of 60 to 75 weight percent, and further comprising an alkoxylated trimethylolpropane triacrylate monomer, the amount thereof is in the range of 2.0 to 25 wt.%, or in the range of 5.0 to 20 wt.%, or in the range of 8.0 to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In one embodiment, the curable secondary composition includes a bisphenol A epoxy diacrylate monomer, in an amount greater than 5.0 wt%, or greater than 10 wt%, or greater than 15 wt%, or in the range of 5.0 wt% to 20 wt%, or in the range of from 8 wt% to 17 wt%, or in the range of from 10 wt% to 15 wt%, and further comprising an ethoxylated bisphenol A diacrylate monomer, in an amount greater than 55 wt%, or greater than 60 wt%, or greater than 65 wt%, or greater than 70 wt%, or in the range of 55 to 80 weight percent, or in the range of 60 to 75 weight percent, and further comprising an ethoxylated trimethylolpropane triacrylate monomer, the amount thereof is in the range of 2.0 to 25 wt.%, or in the range of 5.0 to 20 wt.%, or in the range of 8.0 to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In one embodiment, the curable secondary composition includes a bisphenol A epoxy diacrylate monomer, in an amount greater than 5.0 wt%, or greater than 10 wt%, or greater than 15 wt%, or in the range of 5.0 wt% to 20 wt%, or in the range of from 8 wt% to 17 wt%, or in the range of from 10 wt% to 15 wt%, and further comprising an alkoxylated bisphenol A diacrylate monomer, in an amount greater than 55 wt%, or greater than 60 wt%, or greater than 65 wt%, or greater than 70 wt%, or in the range of 55 to 80 weight percent, or in the range of 60 to 75 weight percent, and further comprising a tris [ (acryloxy) alkyl ] isocyanurate monomer, the amount thereof is in the range of 2.0 to 25 wt.%, or in the range of 5.0 to 20 wt.%, or in the range of 8.0 to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In one embodiment, the curable secondary composition includes a bisphenol A epoxy diacrylate monomer, in an amount greater than 5.0 wt%, or greater than 10 wt%, or greater than 15 wt%, or in the range of 5.0 wt% to 20 wt%, or in the range of from 8 wt% to 17 wt%, or in the range of from 10 wt% to 15 wt%, and further comprising an ethoxylated bisphenol A diacrylate monomer, in an amount greater than 55 wt%, or greater than 60 wt%, or greater than 65 wt%, or greater than 70 wt%, or in the range of 55 to 80 weight percent, or in the range of 60 to 75 weight percent, and further comprising a tris [ (acryloxy) alkyl ] isocyanurate monomer, the amount thereof is in the range of 2.0 to 25 wt.%, or in the range of 5.0 to 20 wt.%, or in the range of 8.0 to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In one embodiment, the curable secondary composition includes a bisphenol A epoxy diacrylate monomer, in an amount greater than 5.0 wt%, or greater than 10 wt%, or greater than 15 wt%, or in the range of 5.0 wt% to 20 wt%, or in the range of from 8 wt% to 17 wt%, or in the range of from 10 wt% to 15 wt%, and further comprising an alkoxylated bisphenol A diacrylate monomer, in an amount greater than 55 wt%, or greater than 60 wt%, or greater than 65 wt%, or greater than 70 wt%, or in the range of 55 to 80 weight percent, or in the range of 60 to 75 weight percent, and further comprising tris (2-hydroxyethyl) isocyanurate triacrylate monomers, the amount thereof is in the range of 2.0 to 25 wt.%, or in the range of 5.0 to 20 wt.%, or in the range of 8.0 to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

In one embodiment, the curable secondary composition includes a bisphenol A epoxy diacrylate monomer, in an amount greater than 5.0 wt%, or greater than 10 wt%, or greater than 15 wt%, or in the range of 5.0 wt% to 20 wt%, or in the range of from 8 wt% to 17 wt%, or in the range of from 10 wt% to 15 wt%, and further comprising an ethoxylated bisphenol A diacrylate monomer, in an amount greater than 55 wt%, or greater than 60 wt%, or greater than 65 wt%, or greater than 70 wt%, or in the range of 55 to 80 weight percent, or in the range of 60 to 75 weight percent, and further comprising tris (2-hydroxyethyl) isocyanurate triacrylate monomers, the amount thereof is in the range of 2.0 to 25 wt.%, or in the range of 5.0 to 20 wt.%, or in the range of 8.0 to 15 wt.%. Preferably, the curable secondary coating composition does not have an alkoxylated bisphenol a diacrylate with a degree of alkoxylation greater than 17, or greater than 20, or greater than 25, or in the range of 15 to 40, or in the range of 20 to 35.

The optional oligomer present in the radiation curable secondary coating composition is preferably a compound having a urethane linkage. In one aspect, the optional oligomer is the reaction product of a polyol compound, a diisocyanate compound, and a hydroxy-functional acrylate compound. The reaction of the polyol compound with the diisocyanate compound provides a urethane linkage, and the hydroxyl functional acrylate compound reacts with the isocyanate group to provide a terminal acrylate group. If present, the total oligomer content in the radiation curable secondary coating composition is less than 3.0 wt.%, or less than 2.0 wt.%, or less than 1.0 wt.%, or in the range of 0 wt.% to 3.0 wt.%, or in the range of 0.1 wt.% to 3.0 wt.%, or in the range of 0.2 wt.% to 2.0 wt.%, or in the range of 0.3 wt.% to 1.0 wt.%. In one embodiment, the radiation curable secondary coating composition is free of oligomers.

One type of optional oligomer is an ethylenically unsaturated oligomer. When included, suitable oligomers may be monofunctional oligomers, multifunctional oligomers, or a combination of monofunctional and multifunctional oligomers. If present, the oligomer component may include aliphatic and aromatic urethane (meth) acrylate oligomers, urea (meth) acrylate oligomers, polyester and polyether (meth) acrylate oligomers, acrylated acrylic oligomers, polybutadiene (meth) acrylate oligomers, polycarbonate (meth) acrylate oligomers, and melamine (meth) acrylate oligomers, or combinations thereof. The curable secondary coating composition may be free of urethane groups, urethane acrylate compounds, urethane oligomers, or urethane acrylate oligomers.

The optional oligomer component of the curable secondary coating composition may include a difunctional oligomer. The bifunctional oligomer has the structure of formula (XVI):

F₁—R₈- [ Carbamate-R₉-carbamic acid esters]_m-R₈—F₁ (XVI)

Wherein, F₁May independently be a reactive functional group, for example, an acrylate, methacrylate, acrylamide, N-vinyl amide, styrene, vinyl ether, vinyl ester, or other functional group known in the art; r₈May independently comprise-C_2-12O—、—(C_2-4—O)_n—、—C_2-12O—(C_2-4—O)_n—、—C_2-12O—(CO—C_2-5O)_n-or-C_2- ₁₂O—(CO—C_2-5NH)_nWherein n is an integer from 1 to 30, including, for example, from 1 to 10; r₉May be a polyether, polyester, polycarbonate, polyamide, polyurethane, polyurea, or a combination thereof; and m is an integer from 1 to 10, including, for example, 1 to 5. In the structure of formula (I), the carbamate moiety can be formed from a diisocyanate and R₉And/or R₈Residues formed by the reaction. The term "independently" is used herein to denote each F₁Can be connected with another F₁In contrast, for each R₈As well as so.

The optional oligomer component of the curable coating composition may include a multifunctional oligomer. The polyfunctional oligomer may have the structure of formula (XVII), formula (XVIII), or formula (XIX):

polycarbamate- (F)₂—R₈—F₂)_x (XVII)

Polyol- [ (aminomethyl)Acid ester-R₉-carbamates)_m-R₈—F₂]_x (XVIII)

Polycarbamate- (R)₈—F₂)_x (XIX)

Wherein, F₂May independently represent 1 to 3 functional groups, for example, acrylate, methacrylate, acrylamide, N-vinyl amide, styrene, vinyl ether, vinyl ester, or other functional groups known in the art; r₈May comprise-C_2-12O—、—(C_2-4—O)_n—、—C_2-12O—(C_2-4—O)_n—、—C_2-12O—(CO—C_2-5O)_n-, or-C_2-12O—(CO—C_2-5NH)_nWherein n is an integer from 1 to 10, including, for example, from 1 to 5; r₉May be a polyether, polyester, polycarbonate, polyamide, polyurethane, polyurea, or a combination thereof; x is an integer from 1 to 10, including, for example, from 2 to 5; and m is an integer from 1 to 10, including, for example, 1 to 5. In the structure of formula (II), the polyamino formate groups may be derived from polyisocyanates and R₉Residues formed by the reaction. Similarly, in the structure of formula (III), the carbamate group may be diisocyanate bonded to R₉And/or R₈The reaction product formed thereafter.

Urethane oligomers can be prepared by reacting an aliphatic or aromatic diisocyanate with a binary polyether or polyester, most commonly a polyoxyalkylene glycol (e.g., polyethylene glycol). The moisture resistant oligomers can be synthesized in a similar manner but avoiding polar polyether or polyester diols and instead using aliphatic diols that are predominantly saturated and predominantly non-polar. These diols may include alkane or alkene diols of about 2 to 250 carbon atoms, which may be substantially free of ether or ester groups.

Elements of polyurea may be included in oligomers prepared by these methods, for example, by replacing diols or polyols with diamines or polyamines during synthesis.

The curable secondary coating composition also includes a photoinitiator, and optionally includes additives such as antioxidants, optical brighteners, amine synergists, adhesion promoters, catalysts, carriers or surfactants, and stabilizers, as described above in connection with the curable primary coating composition.

The curable secondary coating composition includes a single photoinitiator or a combination of two or more photoinitiators. The total photoinitiator content of the curable secondary coating composition is up to about 10 wt%, or between about 0.5 wt% and about 6 wt%.

A representative antioxidant is thiodiethylene bis [3- (3, 5-di-tert-butyl) -4-hydroxyphenyl) propionate ] (e.g., IRGANOX 1035, available from BASF corporation). In some aspects, the antioxidant is present in the curable secondary coating composition in an amount greater than 0.25 wt.%, or greater than 0.50 wt.%, or greater than 0.75 wt.%, or greater than 1.0 wt.%, or in an amount in the range of 0.25 wt.% to 3.0 wt.%, or in an amount in the range of 0.50 wt.% to 2.0 wt.%, or in an amount in the range of 0.75 wt.% to 1.5 wt.%.

Representative brighteners include TINOPAL OB (available from BASF corporation); blankophor KLA [ available from Bayer (Bayer) ]; a bis-benzoxazole compound; a phenylcoumarin compound; and bis (styryl) biphenyl compounds. In one embodiment, the brightener is present in the curable secondary coating composition in a concentration of 0.005 to 0.3 wt.%.

Secondary coating-properties. Relevant properties of the secondary coating include radius, thickness, young's modulus, tensile strength, yield strength, elongation at yield, glass transition temperature, and puncture resistance.

Radius r of the secondary coating₆Less than or equal to 95.0 μm, or less than or equal to 90.0 μm, or less than or equal to 85.0 μm, or less than or equal to 80.0 μm.

In order to facilitate the reduction of the diameter of the optical fiber, it is preferable to make the thickness r of the secondary coating layer₆–r₅And (4) minimizing. Thickness r of the secondary coating₆–r₅Less than or equal to 25.0 μm, or less than or equal to 20.0 μm, or less than or equal to 15.0 μm, or less than or equal to 10.0 μm, or in the range of 5.0 μm to 25.0 μm, or in the range of 8.0 μm to 20.0 μm, or in the range of 10.0 μm to 18.0 μm, or in the range of 12.0 μm to 16.0 μm.

In order to promote the puncture resistance and high protective function, it is preferable that the secondary coating has a high young's modulus. The secondary coating has a Young's modulus greater than or equal to 1600MPa, or greater than or equal to 1800MPa, or greater than or equal to 2000MPa, or greater than or equal to 2200MPa, or in the range of 1600MPa to 2800MPa, or in the range of 1800MPa to 2600 MPa.

An optical fiber drawing process. In a continuous fiber manufacturing process, a glass optical fiber is drawn from a heated preform and sized to a target diameter (typically 125 mm). In some embodiments, the glass fiber has a diameter of 125 microns. In other embodiments, the glass fiber has a diameter less than 110 microns. In other embodiments, the fiber glass diameter is less than 100 microns. The glass optical fiber is then cooled and directed to a coating system that applies a liquid primary coating composition to the glass optical fiber. After applying the liquid primary coating composition to the glass optical fiber, there are two possible process options. In one process option (wet-on-dry process), the liquid primary coating composition is cured to form a cured primary coating, the liquid secondary coating composition is applied to the cured primary coating, and the liquid secondary coating composition is cured to form a cured secondary coating. In the second process option (wet-on-wet process), a liquid secondary coating composition is applied to the liquid primary coating composition and the two liquid coating compositions are cured simultaneously to provide cured primary and secondary coatings. After the fiber exits the coating system, the fiber is collected and stored at room temperature. Collection of the optical fiber typically involves winding the optical fiber onto a spool and storing the spool.

In some processes, the coating system also applies a tertiary coating composition to the secondary coating and cures the tertiary coating composition to form a cured tertiary coating. Typically, the tertiary coating is an ink layer used to mark optical fibers for identification purposes, and its composition contains pigments, while otherwise being similar to the secondary coating. The tertiary coating is applied to the secondary coating and cured. In applying the tertiary coating, the secondary coating is often cured. The primary, secondary, and tertiary coating compositions may be applied and cured in a common continuous manufacturing process. Alternatively, the primary and secondary coating compositions are applied and cured in a common continuous manufacturing process, the coated optical fiber is collected, and the tertiary coating composition is applied and cured in a separate off-line process to form the tertiary coating layer.

The wavelength of the curing radiation is an infrared wavelength, a visible wavelength, or an Ultraviolet (UV) wavelength. Representative wavelengths include wavelengths in the range of 250nm to 1000nm, or in the range of 250nm to 700nm, or in the range of 250nm to 450nm, or in the range of 275nm to 425nm, or in the range of 300nm to 400nm, or in the range of 320nm to 390nm, or in the range of 330nm to 380nm, or in the range of 340nm to 370 nm. Curing may be achieved using a light source including a lamp source (e.g., an Hg lamp), an LED source (e.g., a UVLED, a visible LED, or an infrared LED), or a laser source.

The primary, secondary and tertiary compositions may each be cured using any of the wavelengths and any light sources described above. Each of the primary, secondary, and tertiary compositions may be cured using the same wavelength or light source, or the primary, secondary, and tertiary compositions may be cured using different wavelengths and/or different light sources. Curing of the primary, secondary and tertiary compositions may be achieved using a single wavelength or a combination of two or more wavelengths.

To improve process efficiency, it is desirable to increase the draw speed of the optical fiber along the process path extending from the preform to the collection point. However, as the draw speed increases, the curing speed of the coating composition must increase. The coating compositions disclosed herein are compatible with fiber drawing processes operating at draw speeds greater than 35m/s, or greater than 40m/s, or greater than 45m/s, or greater than 50m/s, or greater than 55m/s, or greater than 60m/s, or greater than 65m/s, or greater than 70 m/s.

The present disclosure extends to an optical fiber coated with a cured product of the coating composition. The optical fiber includes a glass waveguide having a higher index glass core region surrounded by a lower index glass cladding region. The coating formed as a cured product of the coating composition of the present disclosure surrounds and is in direct contact with the glass cladding. The cured product of the coating composition of the present disclosure functions as a primary coating, a secondary coating, or a tertiary coating of an optical fiber.

Examples

The following examples illustrate the preparation of representative primary and secondary coatings. Measurements of selected properties of representative primary and secondary coatings are also described. Furthermore, modeled properties of glass optical fibers coated with primary and secondary coatings and at different coating thicknesses and moduli are presented.

Primary coating — oligomer. The primary coating composition includes an oligomer. For illustrative purposes, a reaction scheme according to the above is described consisting of H12MDI (4, 4' -methylenebis (cyclohexyl isocyanate)), PPG4000 (M)_nPolypropylene glycol of 4000 g/mole) and HEA (2-hydroxyethyl acrylate) to prepare exemplary oligomers. All reagents were used in the manufacturer's supplied form and were not further purified. H12MDI was obtained from ALDRICH. PPG4000 was obtained from COVESTRO and demonstrated to have an unsaturation of 0.004meq/g, as determined according to the method described in ASTM D4671-16 standard. HEA was obtained from KOWA.

The relative amounts of reactants and reaction conditions were varied to obtain a series of 6 oligomers. Oligomers were prepared with different starting molar ratio components, where the molar ratio of the reactants satisfied H12MDI: HEA: PPG4000 ═ n: m: p, where n ranges from 3.0 to 4.0, m ranges from 1.5n-3 to 2.5n-5, and p ═ 2. In the reaction used to form the oligomeric material, dibutyltin dilaurate was used as the catalyst (on the order of 160ppm based on the mass of the initial reaction mixture) and 2, 6-di-tert-butyl-4-methylphenol (BHT) was used as the inhibitor (on the order of 400ppm based on the mass of the initial reaction mixture).

The amounts of reactants used to prepare each of these 6 oligomers are summarized in table 1 below. These six oligomers are identified by individual sample numbers 1-6. Corresponding sample numbers will be used herein to refer to the coating compositions and the cured films formed from the coating compositions independently comprising each of these six oligomers. Table 2 below lists the corresponding moles used in preparing each of these six samples. The number of moles p was normalized to set the number of moles p of PPG4000 to 2.0.

TABLE 1 reactants and amounts of exemplary oligomer samples 1-6

Sample (I)	H12MDI(g)	HEA(g)	PPG4000(g)
				1	22	6.5	221.5
2	26.1	10.6	213.3
				3	26.1	10.6	213.3
4	27.8	12.3	209.9
				5	27.8	12.3	209.9
6	22	6.5	221.5

TABLE 2 moles of oligomer samples 1-6

The oligomer was prepared by combining 4, 4' -methylenebis (cyclohexyl isocyanate), dibutyltin dilaurate, and 2, 6-di-tert-butyl-4-methylphenol in a 500mL flask at room temperature. A500 mL flask was equipped with a thermometer, CaCl₂A drying tube and a stirrer. While the contents of the flask were continuously stirred, the PPG4000 was added over a period of 30-40 minutes using an addition funnel. When the PPG4000 was added, the internal temperature of the reaction mixture was monitored, and the introduction of the PPG4000 was controlledTo prevent overheating (due to the exothermic nature of the reaction). After addition of PPG4000, the reaction mixture is heated in an oil bath at about 70 ℃ to 75 ℃ to about 1 to 1¹/₂And (4) hours. At different time intervals, samples of the reaction mixture were taken for analysis by infrared spectroscopy (FTIR) to monitor the progress of the reaction by determining the concentration of unreacted isocyanate groups. Based on the length of 2265cm^-1The strength of the nearby isocyanate characteristic stretch mode, the concentration of unreacted isocyanate groups was evaluated. The flask was removed from the oil bath and its contents cooled to below 65 ℃. Make-up HEA was added to ensure complete quenching of the isocyanate groups. Make-up HEA was added dropwise over 2-5 minutes using an addition funnel. After addition of the supplemental HEA, the flask was put back into the oil bath and its contents were reheated to about 70 ℃ to 75 ℃ for about 1 to 1¹/₂And (4) hours. FTIR analysis was performed on the reaction mixture to assess the presence of isocyanate groups and the process was repeated until sufficient make-up HEA was added to fully react any unreacted isocyanate groups. The reaction was considered complete when no significant isocyanate stretching strength was detected in the FTIR measurement. The amount of HEA listed in table 1 includes the initial amount of HEA in the composition, as well as the amount of supplemental HEA needed to quench the unreacted isocyanate groups.

The concentration (% by weight) of the binary adduct in each oligomer was determined by Gel Permeation Chromatography (GPC). The concentration of the binary adduct was determined using a Waters Alliance 2690GPC instrument. The mobile phase was THF. The instrument includes a triple polymer laboratory column. Each post is 300mm in length and 7.5mm in internal diameter. Two of the columns (columns 1 and 2) were sold under part number PL1110-6504 by Agilent Technologies and filled with PLgel Mixed D stationary phase (polystyrene divinylbenzene copolymer, average particle size 5 μm, defined molecular weight range 200g/mol to 400,000 g/mol). The third column (column 3) is sold under part number PL1110-6520 by agilent technologies and is packed with PLgel (PL gel) 100A stationary phase (polystyrene divinylbenzene copolymer, average particle size 5 μm, defined molecular weight range up to 4,000 g/mol). These columns were calibrated using EASICAL PS-1 and 2 polymer calibration kits (Agilent technologies, part numbers PL2010-505 and PL2010-0601) with polystyrene standards ranging from 162g/mol to 6,980,000 g/mol. The GPC instrument was operated under the following conditions: flow rate 1.0 mL/min, column temperature 40 ℃, injection volume 100 μ L and run time 35 min (isocratic conditions). The detector was a Waters Alliance 2410 differential refractometer operating at 40 ℃ and having a sensitivity level of 4. Two samples were injected and THF + 0.05% toluene was blank.

The amount of binary adduct (% by weight) in the oligomer is quantified using the GPC system and techniques described previously. A calibration curve was obtained using THF standard solutions containing known amounts of the binary addition compounds (HEA-H12 MDI-HEA). Standard solutions were prepared with binary adduct concentrations of 115.2. mu.g/g, 462.6. mu.g/g, 825.1. mu.g/g, and 4180. mu.g/g. (As used herein, the dimension "μ g/g" refers to μ g of binary adduct per gram of total solution (binary adduct + THF)). Two 100 μ L aliquots of each binary additive standard solution were injected into the column to obtain a calibration curve. The retention time of the binary adduct was about 23 minutes and the GPC peak area of the binary adduct was measured and related to the binary adduct concentration. Obtaining a linear correlation of peak area (correlation coefficient (R) according to the concentration of the binary adduct²)＝0.999564)。

The calibration was used to determine the concentration of the binary adduct in the oligomer. Samples were prepared by diluting 0.10g of oligomeric material in THF to obtain 1.5g of test solution. The test solution was passed through a GPC instrument and the area of the peak associated with the binary addition compound was determined. The binary adduct concentration (in μ g/g) was obtained from the peak area and the calibration curve and converted to weight% by multiplying the weight of the test solution (g) and dividing by the sample weight of the oligomeric material before dilution with THF. The weight% of binary addition compound present in each of the six oligomers prepared in this example is reported in table 2.

Exemplary oligomers include polyether urethane compounds of the type shown above in formula (IV) and enhanced concentrations of binary addition compounds of the type shown above in formula (V) by varying the relative molar ratios of H12MDI, HEA and PPG 4000.

Primary coating-composition. The oligomers corresponding to samples 1-6 were combined separately with the other components to form a series of six coating compositions. The amounts of each component in the coating composition are listed in table 3 below. The entries in table 3 for the oligomers include the combined amount of polyether urethane acrylate compounds and binary addition compounds present in the oligomers. Separate coating compositions were prepared for each of the six exemplary oligomers corresponding to samples 1-6, where the amount of the bis-adduct in the oligomeric material corresponded to the amounts listed in table 2.

TABLE 3 coating compositions

Sartomer SR504 is ethoxylated (4) nonylphenol acrylate (available from sartomer company). V-CAP/RC is N-vinyl caprolactam (available from ISP Technologies). TPO is 2,4, 6-trimethylbenzoyl) diphenylphosphine oxide (available from Pasteur as Lucirin and used as photoinitiator). IRGANOX 1035 is thiodiethylene bis [3- (3, 5-di-tert-butyl) -4-hydroxy-phenyl) propionate ] (available from basf) which acts as an antioxidant. The adhesion promoters were 3-acryloxypropyltrimethoxysilane (from Gelest) and 3-mercaptopropyltrimethoxysilane (from Aldrich). Samples 1, 3 and 5 used 3-acryloxypropyltrimethoxysilane. Samples 2,4 and 6 used 3-mercaptopropyltrimethoxysilane. The tetrathiol is a catalyst quencher.

The coating compositions of table 3 were each formulated using a high speed mixer in a suitable container heated to 60 ℃ and having a heating belt or jacket. In each case, the components were weighed into a container using a balance and allowed to mix until the solid components were completely dissolved and the mixture appeared uniform. The oligomers and monomers (SR504, NVC) of each composition were blended together at 55 ℃ to 60 ℃ for at least 10 minutes. Then, while maintaining the temperature of 55 ℃ to 60 ℃, the photoinitiator, antioxidant, and catalyst quencher were added, and blending was continued for one hour. Finally, an adhesion promoter was added and blending was continued at 55 ℃ to 60 ℃ for 30 minutes to form a coating composition.

Primary coating-property-tensile property. Tensile properties (young's modulus, tensile strength at yield, elongation at yield) were measured on films formed by curing the six coating compositions. Individual films were formed from each coating composition. A wet film of the coating composition was cast on a silicone release paper with the aid of a draw-down box having a gap thickness of about 0.005 ". UV curing apparatus through a radiation depth (Fusion) system with 600W/inch D bulb (50% power and belt speed of about 12 feet/min) at 1.2J/cm²UV dose [ in the wavelength range of 225nm to 424nm, measured by Light Bug model IL490 of International Light]Curing the wet film to obtain a cured coating in the form of a film. The cured film thickness was about 0.0030 "to 0.0035".

The films were allowed to age (23 ℃, 50% relative humidity) for at least 16 hours prior to testing. The film samples were cut to a size of 12.5cm x13mm using a cutting template and a scalpel. Young's modulus, tensile strength at yield and elongation at yield were measured on film samples at room temperature (about 20 ℃) using an MTS SINTECH tensile tester in accordance with the procedures set forth in ASTM Standard D882-97. Young's modulus is defined as the steepest slope at the beginning of the stress-strain curve. The film was tested at an elongation rate of 2.5 cm/min and an initial gauge length of 5.1 cm. The results are shown in Table 4.

TABLE 4 Young's modulus, tensile Strength, and elongation of film samples

Sample (I)	Young's modulus (MPa)	Tensile Strength (MPa)	Elongation (%)
				1	0.72	0.51	137.9
2	0.57	0.44	173
				3	1.0	0.86	132.8
4	0.71	0.45	122.3
				5	0.72	0.56	157.4
6	0.33	0.33	311.9

Primary coating-Properties-in situ modulus. In situ modulus measurements were performed for coating composition samples 2, 3, and 5. In situ modulus measurements require the formation of a primary coating on a 125 μm diameter glass fiber. Each of samples 2, 3 and 5 was separately applied to the glass optical fiber as a primary coating composition as the glass optical fiber was drawn. The fiber drawing speed was 50 m/s. A stack of five LED sources was used to cure the primary coating composition. Each LED source operated at 395nm and an intensity of 12W/cm². After the primary coating composition is applied and cured, a secondary coating composition is applied to each cured primary coating layer and cured using a UV source to form a secondary coating layer. The thickness of the primary coating was 32.5 μm and the thickness of the secondary coating was 26.0 μm.

The in situ modulus was measured using the following procedure. A 6 inch sample of the fiber was obtained, stripped in a window 1 inch section from the center of the fiber, and wiped with isopropyl alcohol. The stripped fiber was mounted on a sample holder/alignment table equipped with a10 mm x 5mm rectangular aluminum tab for securing the fiber. The two tabs are oriented horizontally and positioned so that the 5mm short sides face each other and are separated by a 5mm gap. The windowed fiber is placed horizontally on the sample holder and through the tabs and over the gaps separating the tabs. The coated end of one side of the region of the fiber stripping window was positioned on one tab and extended into one half of the 5mm gap between the tabs. An area of one inch of the peel window extends over the remaining half of the gap and spans the opposing tab. After alignment, the sample was moved and a small spot of glue was applied to the half of each tab closest to the 5mm gap. The fiber is then returned to position and the alignment stage is raised until the glue just touches the fiber. The coated end was then pulled away from the gap and through the glue so that the majority of the 5mm gap between the tabs was occupied by the area of the stripping window of the optical fiber. The area part of the peeling window still on the opposite tab is in contact with the glue. Leaving the most pointed end of the coated end to extend beyond the gap and into the gap between the tabs. This part of the coated end is not embedded in the glue and is the subject of in situ modulus measurement. The glue is allowed to dry along with the fiber sample in this configuration to secure the fiber to the tab. After drying, the length of the optical fiber secured to each tab was cut to 5 mm. The coated length was embedded in glue and the un-embedded coated length (the portion extending into the gap between the tabs) and the primary diameter were measured.

In situ modulus measurements were performed on a Rheometrics DMTA IV dynamic mechanical testing apparatus at a constant strain of 9 e-61/s for a period of 45 minutes at room temperature (21 ℃). The gauge length is 15 mm. The force and length changes were recorded and used to calculate the in situ modulus of the primary coating. The tabbed fiber samples were prepared by removing any epoxy from the tab that would interfere with the 15mm gripping length of the testing equipment to ensure that the clamp did not contact the fiber and that the sample was held vertically in the clamp. The instrument force was zeroed. The tab with the uncoated end of the optical fiber secured thereto is then mounted to the lower fixture (measurement probe) of the testing apparatus, and the tab with the coated end of the optical fiber secured thereto is mounted to the upper (stationary) fixture of the testing apparatus. The test is then performed and once the analysis is complete, the sample is removed.

Table 5 lists the in situ modulus of the primary coating samples 2, 3 and 5.

TABLE 5 in situ moduli of selected Primary coatings

Sample (I)	In situ modulus (MPa)
		2	0.27
3	0.33
		5	0.3

A secondary coating composition. Representative curable secondary coating compositions are listed in table 6.

TABLE 6 Secondary coating compositions

SR601 is ethoxylated (4) bisphenol A diacrylate (monomer). SR602 is ethoxylated (10) bisphenol a diacrylate (monomer). SR349 is ethoxylated (2) bisphenol A diacrylate (monomer). SR399 is dipentaerythritol pentaacrylate. SR499 is ethoxylated (6) trimethylolpropane triacrylate. CD9038 is ethoxylated (30) bisphenol a diacrylate (monomer). Photomer3016 is bisphenol a epoxy diacrylate (monomer). TPO is a photoinitiator. Irgacure 1841 is 1-hydroxycyclohexyl-phenyl ketone (photoinitiator). Irgacure 1850 is bis (2, 6-dimethoxybenzoyl) -2,4, 4-trimethylpentylphosphine oxide (photoinitiator). Irganox 1035 is thiodiethylene bis (3, 5-di-tert-butyl) -4-hydroxyhydrocinnamate (antioxidant). DC190 is a silicone-ethylene oxide/propylene oxide copolymer (slip agent). The concentration unit "pph" refers to the amount of base composition relative to the base composition, which includes all monomers, oligomers, and photoinitiators. For example, for a secondary coating composition KA, a concentration of DC-190 of 1.0pph corresponds to 1g DC-190 per 100g of combined SR601, CD9038, Photomer3016, TPO and Irgacure 184.

Comparative curable secondary coating composition (a) and three representative curable secondary coating compositions (SB, SC, and SD) within the scope of the present disclosure are listed in table 7.

TABLE 7 Secondary coating compositions

PE210 is bisphenol A epoxy diacrylate [ available from Korea I and Chemicals (Miwon Specialty Chemicals) ], M240 is ethoxylated (4) bisphenol A diacrylate [ available from Korea I and Chemicals ], M2300 is ethoxylated (30) bisphenol A diacrylate [ available from Korea I and Chemicals ], M3130 is ethoxylated (3) trimethylolpropane triacrylate [ available from Korea I and Chemicals ], TPO (photoinitiator) is (2,4, 6-trimethylbenzoyl) diphenylphosphine oxide [ available from Passion ], Irgacure 184 (photoinitiator) is 1-hydroxycyclohexyl-phenyl ketone [ available from Passion ], Irganox 1035 (antioxidant) is 3, 5-bis (1, 1-dimethylethyl) -4-hydroxythiodi-2 phenylpropionate, 1-ethylene glycol ester (available from basf corporation). DC190 (slip agent) is a silicone-ethylene oxide/propylene oxide copolymer (available from the dow chemical company). The concentration unit "pph" refers to the amount of base composition comprising all monomers and photoinitiator. For example, for secondary coating composition A, a concentration of DC-190 of 1.0pph corresponds to 1g DC-190 per 100g of combined PE210, M240, M2300, TPO and Irgacure 184.

Secondary coating-properties. Young's modulus, tensile strength at break and elongation at break of secondary coatings made from secondary compositions A, KA, KB, KC, KD, SB, SC and SD were measured.

Secondary coating-Properties-measurement techniques. The properties of the secondary coating were determined using the following measurement techniques:

tensile properties.Curing the curable secondary coating composition and configuring it in the form of a cured bar sample for measuring Young's modulus, tensile strength at yield, and strength at yieldDegree and elongation at yield. By injecting a curable secondary composition into the cavity having an internal diameter of about 0.025 ″Cured rods were prepared in tubes. Using a deep-radiating D bulb at about 2.4J/cm²(measured by Light Bug model IL390 from International Light sources, inc. (International Light) in the wavelength range of 225-424 nm). After curing, peeling offThe tube was used to provide a cured rod sample of the secondary coating composition. The cured bars were allowed to stand at 23 ℃ and 50% relative humidity for 18-24 hours prior to testing. Young's modulus, tensile strength at break, yield strength and elongation at yield were measured on defect free bar samples with gauge length of 51mm and test speed of 250 mm/min using a Sintech MTS tensile tester. Tensile properties were measured according to ASTM standard D882-97. The property is determined as an average of at least five samples, and the average excludes defective samples.

Glass transition temperature.In situ T of primary and secondary coatings on fiber-optic release samples obtained from coated optical fibers_gAnd (6) measuring. The coated optical fiber included a glass optical fiber having a diameter of 125 μm, a primary coating having a thickness of 32.5 μm surrounding and directly contacting the glass optical fiber, and a secondary coating having a thickness of 26.0 μm surrounding and directly contacting the glass optical fiber. The glass fiber and the primary coating were the same for all samples measured. The primary coating layer is formed from a reference primary coating composition described below. Samples with comparative secondary coatings and the secondary coatings of the present disclosure were measured.

Fiber optic extubation samples were obtained using the following procedure: a0.0055 "Miller (MILLER) stripper was clamped down from the end of the coated fiber about 1 inch. This one inch region of the fiber was immersed into a flow of liquid nitrogen and held in the liquid nitrogen for 3 seconds. The coated fiber was then removed from the liquid nitrogen stream and quickly stripped to remove the coating. The stripped end of the fiber is inspected for residual coating. If there is still residual coating on the glass fiber, the sample is discarded and a new sample is prepared. The result of the stripping process is a clean glass fiber and stripped coated hollow tube that includes a complete primary and secondary coating. This hollow tube is referred to as the "off-tube sample". The diameters of the glass, primary coating and secondary coating were measured from the end face of the unpeeled optical fiber.

The in situ Tg of the extubated samples was run using a Rheometrics DMTA IV tester at sample gauge lengths of 9 to 10 mm. The width, thickness and length of the extubated sample are input into the operating program of the test instrument. The extubated sample was installed and then cooled to about-85 ℃. Once stabilized, the temperature ramp was run with the following parameters:

frequency: 1Hz

Strain: 0.3 percent of

Heating rate: 2 ℃/min.

Final temperature: 150 ℃ C

Initial static force 20.0g

The static force is 10.0 percent larger than the dynamic force

The in situ Tg of the coating is defined as the maximum value of tan δ in a plot of tan δ as a function of temperature, where tan δ is defined as:

tanδ＝E”/E'

and E "is the loss modulus, which is proportional to the energy loss as heat in the deformation cycle, and E' is the storage or elastic modulus, which is proportional to the energy stored in the deformation cycle.

The decapped samples exhibited a significant maximum in the tan delta plot for the primary and secondary coatings. The maximum at lower temperatures (about-50 ℃) corresponds to the in situ Tg of the primary coating, while the maximum at higher temperatures (above 50 ℃) corresponds to the in situ Tg of the secondary coating.

In situ modulus of the secondary coating.For the secondary coating, in situ modulus was measured using fiber optic release samples prepared from fiber optic samples. A0.0055 inch Miller (MILLER) stripper was clamped down about 1 inch from the end of the fiber sample. The one inch region of the fiber sample was submerged in the liquid nitrogen stream and held for 3 seconds. The fiber sample was then removed and quickly stripped. Followed byThe stripped end of the fiber sample was inspected. If the coating is still on the glass portion of the fiber sample, the extubated sample is deemed invalid and a new extubated sample is prepared. A suitable tubeless sample is a hollow tube that cleanly peels from glass and consists of a primary coating and a secondary coating. The diameters of the glass, primary coating and secondary coating were measured from the end face of the unpeeled optical fiber sample.

Fiber-optical release samples were run at a sample gauge length of 11mm using a Rheometrics DMTA IV instrument to obtain the in situ modulus of the secondary coating. The width, thickness and length are determined and provided as inputs to the instrument operating software. The samples were mounted and run at ambient temperature (21 ℃) using a time scanning program using the following parameters:

frequency: 1 radian/second

Strain: 0.3 percent of

Total time 120 seconds

The time of each measurement is 1 second

Initial static force 15.0g

The static force is 10.0 percent larger than the dynamic force

Once completed, the last five E' (storage modulus) data points were averaged. Three runs of each sample (with a new sample for each run) were made for a total of 15 data points. The average of three runs is reported.

Puncture resistance of the secondary coating.Puncture resistance measurements were performed on samples including glass fiber, primary coating and secondary coating. The diameter of the glass fiber was 125. mu.m. The primary coating was formed from the reference primary coating composition listed in table 8 below. Samples with various secondary coatings were prepared as follows. The thicknesses of the primary and secondary coatings are adjusted to vary the cross-sectional area of the secondary coating, as described below. The ratio of the thickness of the secondary coating to the thickness of the primary coating was maintained at about 0.8 for all samples.

Puncture Resistance was measured using the technique described in an article entitled "Quantifying the Puncture Resistance of Optical Fiber Coatings" by G.Scott Glaesemann and Donald A.Clark, published in the 52 nd International wireProceedings of the 52 Cable conference^nd International Wire&Cable Symposium), pages 237 and 245 (2003). An overview of the method is provided herein. The method is an indentation method. A 4 cm length of optical fiber was placed on a 3mm thick glass slide. One end of the fiber is attached to a device that rotates the fiber in a controlled manner. The transmission of the fiber was examined at 100 x magnification and rotated until the secondary coating thickness was equal on both sides of the glass fiber in the direction parallel to the slide. In this position, the thickness of the secondary coating is equal on both sides of the fiber in the direction parallel to the slide. The thickness of the secondary coating in a direction perpendicular to the glass slide and above or below the glass optical fiber is different from the thickness of the secondary coating in a direction parallel to the glass slide. One of the thicknesses in the direction perpendicular to the slide glass is larger than the thickness in the direction parallel to the slide glass, and the other thickness in the direction perpendicular to the slide glass is smaller than the thickness in the direction parallel to the slide glass. This position of the optical fiber is fixed by sticking the optical fiber to a glass slide at both ends, and is the optical fiber position for indentation test.

Indentation was performed using a universal testing machine (Instron model 5500R or equivalent). The inverted microscope was placed below the crosshead of the testing machine. The microscope's objective lens was located directly below a 75 ° diamond wedge indenter mounted in the testing machine. The slide with the fiber adhered to it was placed on the microscope stage and directly under the indenter so that the width of the indenter wedge was orthogonal to the direction of the fiber. When the fiber is in place, the diamond wedge is lowered until it contacts the surface of the secondary coating. The stone wedges were then driven into the secondary coating at a rate of 0.1 mm/min and the load on the secondary coating was measured. As the diamond wedge is driven deeper into the secondary coating until penetration occurs, the load on the secondary coating increases, and a sharp decrease in load is observed as penetration occurs. The indentation load at which puncture was observed was recorded and reported herein in grams of force. The experiment was repeated for the same orientation of fiber to obtain ten measurement points, which were averaged to determine the puncture resistance of the orientation. The second set of ten measurement points is obtained by rotating the fiber orientation by 180 °.

And (5) slightly bending. In the wire mesh covered cylinder test, the attenuation of light at a wavelength of 1550nm through a coated optical fiber having a length of 750m was determined at room temperature. Microbend-induced attenuation was determined by the difference between zero-tension and high-tension deployments on the wire mesh drum. Separate measurements were made for both winding configurations. In a first configuration, the fiber was wound in a zero tension configuration on an aluminum drum having a smooth surface and a diameter of about 400 mm. The zero tension wound configuration provides stress-free reference attenuation of light through the fiber. After a sufficient dwell time, an initial attenuation measurement is taken. In a second winding configuration, the fiber sample was wound onto an aluminum drum wound with a fine wire mesh. For this deployment, the barrel surface of the aluminum barrel is covered with a wire mesh, and the optical fiber is wrapped around the wire mesh. The mesh was tightly wrapped around the barrel without stretching and remained intact without holes, dents, tears or damage. The wire mesh material used for the measurements was made of a corrosion resistant type 304 stainless steel braided wire cloth and had the following characteristics: mesh per linear inch: 165x165, wire diameter: 0.0019 ", width opening: 0.0041 "and% open area 44.0. A750 m length of coated fiber was wound onto a wire-mesh covered drum at a take-up pitch (take-up pitch) of 0.050cm at 1m/s while applying a tension of 80(+/-1) grams. The ends of the fibers were taped to maintain tension and no fiber crossover. The point of contact of the wound fiber with the web imparts stress to the fiber, and the attenuation of light through the wound fiber is a measure of the stress-induced (microbend) loss of the fiber. After a residence time of 1 hour, a bobbin measurement was carried out. For each wavelength, the increase in fiber attenuation (in dB/km) when measured in the second configuration (wire-mesh covered cylinder) relative to the first configuration (smooth cylinder) was determined. The average of three trials at each wavelength was determined and reported as net microbending loss.

Reference is made to the primary coating. In situ measurement of glass transition temperature (T)_g) Puncture resistance and wire mesh covered microbend attenuation, the measurement sample included a primary coating between the glass fiber and a secondary coating. Primary coatingThe compositions have the formulations given in table 8 and are typical of commercially available primary coating compositions.

TABLE 8 reference Primary coating compositions

Wherein the oligomeric material is prepared as described above from H12MDI, HEA and PPG4000 using the molar ratio N: m: p ═ 3.5:3.0:2.0, SR504 is ethoxylated (4) nonylphenol acrylate (from sartomer), NVC is N-vinylcaprolactam (from aldrich), TPO (photoinitiator) is (2,4, 6-trimethylbenzoyl) -diphenylphosphine oxide (from basf), Irganox 1035 (antioxidant) is phenylpropionic acid 3, 5-bis (1, 1-dimethylethyl) -4-hydroxythiodi-2, 1-ethanediol (from basf), 3-acryloxypropyltrimethoxysilane is an adhesion promoter (from Gelest), and pentaerythritol tetrakis (3-mercaptopropionate) (also known as tetrathiol, available from aldrich) is a chain transfer agent. The concentration unit "pph" refers to the amount of base composition relative to the base composition, which includes all monomers, oligomers, and photoinitiators. For example, a concentration of 1.0pph of Irganox 1035 corresponds to 1g of Irganox 1035 per 100g of combined oligomeric material, SR504, NVC, and TPO.

Secondary coating-properties-tensile properties. Tensile property measurements are shown in table 9, according to the curable secondary composition preparation.

TABLE 9 tensile Properties of Secondary coating

The results show that the secondary coatings prepared from compositions SB, SC, and SD exhibit higher young's modulus and higher yield strength than the secondary coating prepared from comparative composition a. Higher values represent advances that make secondary coatings prepared for the curable coating compositions disclosed herein more suitable for small diameter optical fibers. More specifically, higher values enable the use of thinner secondary coatings on optical fibers without sacrificing performance. Thinner secondary coatings reduce the overall diameter of the optical fiber and provide a higher fiber count in a cable of a given cross-sectional area.

The secondary coating prepared as a cured product of the curable secondary coating composition disclosed herein has a young's modulus of greater than 2400MPa, or greater than 2500MPa, or greater than 2600MPa, or greater than 2700MPa, or in the range of 2400MPa to 3000MPa, or in the range of 2600MPa to 2800 MPa.

The yield strength of the secondary coating prepared as the cured product of the curable secondary coating composition disclosed herein is greater than 55MPa, or greater than 60MPa, or greater than 65MPa, or greater than 70MPa, or in the range of 55MPa to 75MPa, or in the range of 60MPa to 70 MPa.

Secondary coating-Properties-puncture resistance. The puncture resistance of the secondary coatings made from comparative curable secondary coating composition a, a commercially available curable secondary coating composition (CPC6e) from the supplier (DSM Desotech) having a proprietary composition, and curable secondary coating composition SD was determined according to the method described above. Several fiber samples were prepared with each of these three secondary coatings. Each of the optical fiber samples included a glass optical fiber having a diameter of 125 μm, a primary coating formed from the reference primary coating composition listed in Table 8, and one of the three secondary coatings. Samples with various secondary coatings were prepared. The thicknesses of the primary coating and the secondary coating are adjusted to change the sectional area of the secondary coating, as shown in fig. 7. The ratio of the thickness of the secondary coating to the thickness of the primary coating was maintained at about 0.8 for all samples.

For each secondary coating, a range of thickness of optical fiber samples were prepared to determine the dependence of the puncture load on the secondary coating thickness. One strategy for achieving higher fiber counts in fiber optic cables is to reduce the thickness of the secondary coating. However, as the secondary coating thickness decreases, its performance becomes weaker and its protective function is impaired. Puncture resistance is a measure of the protective function of a secondary coating. Secondary coatings with high puncture resistance withstand greater impact without failure and provide better protection for glass optical fibers.

Fig. 7 shows the variation of the piercing load according to the cross-sectional area of the three coatings. The cross-sectional area was chosen as a parameter for reporting the puncture load because the puncture load was observed to be approximately linearly related to the cross-sectional area of the secondary coating. Traces 72, 74, and 76 show that for comparative secondary coatings obtained by curing comparative CPC6e secondary coating composition, comparative curable secondary coating composition a, and curable secondary coating composition SD, a generally linear dependence of puncture load on cross-sectional area was observed, respectively. The viewer is provided with a vertical dotted line as an indication of 10000 μm²、15000μm²And 20000 μm²Of the cross-sectional area of the cylinder.

The CPC6e secondary coating shown by trace 72 corresponds to a conventional secondary coating known in the art. The comparative secondary coating a shown in trace 74 shows an improvement in puncture load for high cross-sectional areas. However, as the cross-sectional area decreases, the improvement decreases. This indicates that the secondary coating obtained as a cured product of the comparative curable secondary coating composition a is unlikely to be suitable for low-diameter, high-fiber-count applications. In contrast, trace 76 shows a significant increase in puncture load for the secondary coating obtained as the cured product of the curable secondary coating composition SD. For example at 7000 μm²The secondary coating obtained from the curable secondary coating composition SD has a puncture load 50% or more greater than that of either of the other two secondary coatings.

At 10000 μm²A puncture load of a secondary coating layer formed as a cured product of the curable secondary coating composition disclosed herein is greater than 36g, or greater than 40g, or greater than 44g, or greater than 48g, or in the range of 36g to 52g, or in the range of 40g to 48 g. At 15000 μm²A puncture load of a secondary coating layer formed as a cured product of the curable secondary coating composition disclosed herein is greater than 56g, or greater than 60g, or greater than 64g, or greater than 68g, or in the range of 56g to 72g, or in the range of 60g to 68 g. At 20000 μm²A puncture load of a secondary coating layer formed as a cured product of the curable secondary coating composition disclosed herein is greater than 68g, or greater than 72g, or greater than 76g, or greater than 80g, or in the range of 68g to 92g, or in the range of 72g to 88 g. Embodiments include secondary coatings having any combination of the foregoing puncture loads.

As used herein, normalized puncture load refers to the ratio of puncture load to cross-sectional area. The puncture load of the secondary coating layer formed as the cured product of the curable secondary coating composition disclosed herein has the following normalized puncture load: greater than 3.2x10^-4g/μm²Or greater than 3.6x10^-4g/μm²Or greater than 4.0x10^-4g/μm²Or greater than 4.4x10^-4g/μm²Or greater than 4.8x10^-4g/μm²Or at 3.2x10^-4g/μm²To 5.6x10^-4g/μm²Or in the range of 3.6x10^-4g/μm²To 5.2x10^-4g/μm²Or in the range of 4.0x10^-4g/μm²To 4.8x10^-4g/μm²Within the range of (1).

Secondary coating-property-microbending. Attenuation due to fiber microbending was measured according to the wire mesh covered canister test described above. The fiber sample had a glass fiber with a relative refractive index profile 90 shown in fig. 6. Radius r of glass optical fiber₄62.5 μm and is surrounded by a primary coating having a thickness of 36.5 μm, which is surrounded by a secondary coating having a thickness of 26 μm. The primary coating was formed from the reference primary coating composition listed in table 8, and the secondary coating was formed from the comparative coating composition a listed in table 7. Measurements were made on several fibers and it was observed that the attenuation at 1550nm, as determined by the cylinder test of wire mesh coverage, was between 0.05dB/km and 0.8dB/km for all samples. The attenuation of the optical fiber is less than 1.0dB/km, or less than 0.8dB/km, or less than 0.6dB/km, or less than 0.4dB/km, or less than 0.2dB/km, or in the range of 0.05dB/km to 1.0dB/km, or in the range of 0.15dB/km to 0.80dB/km, or in the range of 0.30dB/km to 0.70 dB/km.

Modeling the result. The experimental examples and principles disclosed herein indicate that by varying the moles n, m and p, the relative amounts of the binary addition compounds in the oligomers, as well as the properties of the cured films formed from the primary coating compositions, can be controlled over a wide range, including the ranges of young's modulus and in situ modulus specified herein. Similarly, variations in the type and concentration of different monomers in the secondary composition cause the young's modulus to vary within the ranges disclosed herein. The amount of cure is another parameter that can be used to alter the modulus of the primary and secondary coatings formed from the curable compositions disclosed herein.

To examine the effect of the thickness and modulus of the primary and secondary coatings on the transmission of radial force to the glass fiber, a series of modeled embodiments were considered. In the model, a radially external load P is applied to the secondary coating surface of the optical fiber, and the resulting load at the surface of the glass optical fiber is calculated. Glass fibers were modeled with a young's modulus of 73.1GPa (consistent with silica glass) and a diameter of 125 μm. Poisson ratio v of primary coating and secondary coating_pV and v_sFixed at 0.48 and 0.33, respectively. A comparative sample C1 and six samples of the present disclosure, M1-M6, are contemplated. The comparative samples included a primary coating and a secondary coating having a thickness and modulus consistent with optical fibers known in the art. Samples M1-M6 are examples of reduced thickness of the primary and secondary coatings. Table 10 summarizes the parameters describing the configuration of the primary and secondary coatings.

TABLE 10 coating Properties of modeled fibers

Table 11 summarizes the load P1 at the outer surface of the glass fiber as a fraction of the load P applied to the secondary coating surface. The ratio P1/P is referred to herein as the load transfer parameter and corresponds to the fraction of the applied load P transmitted through the primary and secondary coatings to the surface of the glass optical fiber. The load P is a radial load, and the load transfer parameter P1/P is calculated by a model based on equations (9) - (11):

wherein

And is

B＝((1-2ν_p(r₄/r₅)²+(r₄/r₅)²)(1-2ν_s(r₅/r₆)²+(r₅/r₆)²)) (11)

In equations (9) - (11), v_pV and v_sIs the Poisson ratio, r, of the primary and secondary coatings₄Is the outer radius of the glass fiber, r₅Is the outer radius of the primary coating, r₆Is the outer radius of the secondary coating, E_pIs the in situ modulus of the primary coating, and E_sIs the young's modulus of the secondary coating. The scaled load transfer parameter P1/P (scaling) in Table 11 corresponds to the ratio P1/P for each sample relative to the comparative sample C1.

TABLE 11 load transfer parameters at the surface of the glass fiber (P1/P)

The modeled examples show that despite the smaller coating thickness, optical fibers having the primary and secondary coatings described herein exhibit reduced forces experienced by glass optical fibers relative to comparative optical fibers having conventional primary and secondary coatings with conventional thicknesses. The resulting reduction in the overall size of the optical fibers described herein enables a higher fiber count in a cable of a given size (or a smaller cable diameter for a given fiber count) without increasing the risk of glass fiber damage due to external forces.

Scaled load transfer parameter P for secondary coating₁(ii) a/P (scaled) of less than 0.99, or less than 0.97, or less than 0.95. Load transfer parameter P of the secondary coating₁the/P is less than 0.0200, or less than 0.0180, or less than 0.0178, or less than 0.0176, or less than 0.0174, or less than 0.0172, or less than 0.0170, or less than 0.0168, or in the range of 0.0160-0.0180, or in the range of 0.0162-0.0179, or in the range of 0.0164-0.0178, or in the range of 0.0166-0.0177, or in the range of 0.0168-0.0176.

Clause 1 of the present disclosure extends to:

an optical fiber, comprising:

A cladding region surrounding and directly adjacent to the core region, the cladding region having a radius r in the range of 37.5 μm to 62.5 μm₄；

Clause 2 of the present disclosure extends to:

the optical fiber of clause 1, wherein the silica glass is free of GeO₂。

Clause 3 of the present disclosure extends to:

the optical fiber of clause 1 or 2, wherein the radius r₁In the range of 4.0 μm to 8.0 μm.

Clause 4 of the present disclosure extends to:

the optical fiber of any of clauses 1-3, wherein Δ_{1 max}In the range of-0.05% to 0.15%.

Clause 5 of the present disclosure extends to:

the optical fiber of any of clauses 1-4, wherein the core region has a minimum relative refractive index Δ in the range of-0.20% to 0.10%_{1 minimum}And wherein, Δ_{1 max}And delta_{1 minimum}The difference is greater than 0.10%.

Clause 6 of the present disclosure extends to:

the optical fiber of any of clauses 1-5, wherein the core region comprises a portion having a constant relative refractive index and the width of the portion in the radial direction is at least 2.0 μm.

Clause 7 of the present disclosure extends to:

the optical fiber of any of clauses 1-6, wherein the radius r₄In the range of 42.5 μm to 57.5 μm.

Clause 8 of the present disclosure extends to:

the optical fiber of any of clauses 1-7, wherein the cladding region comprises an outer cladding region having a relative refractive index Δ in the range of-0.45% to-0.15%₄。

Clause 9 of the present disclosure extends to:

the optical fiber of any of clauses 1-8, wherein the core region comprises an inner core region and an outer core region, the inner core region having a radius r in the range of 0.25 μ ι η to 3.0 μ ι η_aThe outer core region has a radius r₁。

Clause 10 of the present disclosure extends to:

the optical fiber of clause 9, wherein the inner core region has a relative refractive index profile described by an α -profile and an α value is less than 10, and the outer core region has a relative refractive index profile described by an α -profile and an α value is greater than 50.

Clause 11 of the present disclosure extends to:

the optical fiber of any of clauses 1-10, wherein the cladding region comprises a depressed-index cladding region directly adjacent to the core region, and an outer cladding region surrounding and directly adjacent to the depressed-index cladding region, the depressed-index cladding region having a radius r₃Relative refractive index delta in the range of-0.20% to-0.70%₃The outer cladding layer has a radius r₄And a relative refractive index delta in the range of-0.60% to 0.0%₄。

Clause 12 of the present disclosure extends to:

the optical fiber of clause 11, wherein the depressed index cladding region has a thickness in the range of 5.0 μm to 20.0 μm.

Clause 13 of the present disclosure extends to:

the optical fiber of clause 11 or 12, wherein the radius r₃In the range of 10.0 μm to 30.0 μm.

Clause 14 of the present disclosure extends to:

the optical fiber of any of clauses 1-13, wherein the radius r₅Less than or equal to 80 μm.

Clause 15 of the present disclosure extends to:

the optical fiber of any of clauses 1-14, wherein the thickness r₅–r₄In the range of 10.0 μm to 17.0 μm.

Clause 16 of the present disclosure extends to:

the optical fiber of any of clauses 1-15, wherein the primary coating is a cured product of a coating composition comprising:

a radiation-curable monomer;

an adhesion promoter comprising an alkoxysilane compound or a mercapto-functional silane compound; and

an oligomer comprising:

a polyether urethane acrylate compound having the following formula:

wherein the content of the first and second substances,

R₁、R₂and R₃Independently selected from linear alkylene, branched alkylene or cycloalkylene;

y is 1, 2, 3 or 4; and is

x is between 40 and 100; and

a binary addition compound having the formula:

wherein the binary addition compound is present in the oligomer in an amount of at least 1.0 wt%.

Clause 17 of the present disclosure extends to:

the optical fiber of clause 16, wherein the binary addition compound is present in the oligomer in an amount of at least 1.0 wt.%.

Clause 18 of the present disclosure extends to:

the optical fiber of clause 16, wherein the binary addition compound is present in the oligomer in an amount of at least 3.5 weight percent.

Clause 19 of the present disclosure extends to:

the optical fiber of any of clauses 16-18, wherein the oligomer is a cured product of a reaction between:

a diisocyanate compound;

a hydroxy (meth) acrylate compound; and

a polyol compound having an unsaturation of less than 0.1 meq/g;

Clause 20 of the present disclosure extends to:

the optical fiber of any of clauses 1-19, wherein the radius r₆Less than or equal to 90.0 μm.

Clause 21 of the present disclosure extends to:

the optical fiber of any of clauses 1-19, wherein the radius r₆Less than or equal to 85.0 μm.

Clause 22 of the present disclosure extends to:

the optical fiber of any of clauses 1-21, wherein the young's modulus is greater than 1800 MPa.

Clause 23 of the present disclosure extends to:

the optical fiber of any of clauses 1-21, wherein the young's modulus is greater than 2000 MPa.

Clause 24 of the present disclosure extends to:

the optical fiber of any of clauses 1-21, wherein the young's modulus is greater than 2500 MPa.

Clause 25 of the present disclosure extends to:

the optical fiber of any of clauses 1-24, wherein the thickness r₆–r₅In the range of 10.0 μm to 18.0 μm.

Clause 26 of the present disclosure extends to:

the optical fiber of any of clauses 1-25, wherein the secondary coating is a cured product of a composition comprising:

a first monomer comprising a first bisphenol-A diacrylate compound.

Clause 27 of the present disclosure extends to:

the coating composition of clause 26, further comprising a second monomer comprising a second bisphenol-a diacrylate compound.

Clause 28 of the present disclosure extends to:

the coating composition of clause 27, wherein the first bisphenol a diacrylate compound is an alkoxylated bisphenol a diacrylate compound and the second bisphenol a diacrylate compound is a bisphenol a epoxy diacrylate compound.

Clause 29 of the present disclosure extends to:

the optical fiber of any of clauses 1-25, wherein the secondary coating is a cured product of a composition comprising:

an alkoxylated bisphenol-A diacrylate monomer in an amount greater than 55 weight percent, the alkoxylated bisphenol-A diacrylate monomer having a degree of alkoxylation of from 2 to 16; and

Clause 30 of the present disclosure extends to:

the optical fiber of clause 29, wherein the alkoxylated bisphenol a diacrylate monomer is present in an amount of 60 to 75 wt.%.

Clause 31 of the present disclosure extends to:

the optical fiber of clause 29 or 30, wherein the alkoxylated bisphenol a diacrylate monomer has a degree of alkoxylation in the range of 2 to 8.

Clause 32 of the present disclosure extends to:

the optical fiber of any of clauses 29-31, wherein the alkoxylated bisphenol a diacrylate monomer is an ethoxylated bisphenol a diacrylate monomer.

Clause 33 of the present disclosure extends to:

the optical fiber of any of clauses 29-32, wherein the triacrylate monomers are present in an amount of 8.0 to 15 wt.%.

Clause 34 of the present disclosure extends to:

the optical fiber of any of clauses 29-33, wherein the alkoxylated trimethylolpropane triacrylate monomer has a degree of alkoxylation in the range of 2 to 8.

Clause 35 of the present disclosure extends to:

the optical fiber of any of clauses 29-34, wherein the alkoxylated trimethylolpropane triacrylate monomer is an ethoxylated trimethylolpropane triacrylate monomer.

Clause 36 of the present disclosure extends to:

the optical fiber of any of clauses 29-35, wherein the tris [ (acryloxy) alkyl ] isocyanurate monomer is tris (2-hydroxyethyl) isocyanurate triacrylate monomer.

Clause 37 of the present disclosure extends to:

the optical fiber of any of clauses 29-36, further comprising a bisphenol-a epoxy diacrylate monomer in an amount in the range of 5.0 wt.% to 20 wt.%.

Clause 38 of the present disclosure extends to:

the optical fiber of any of clauses 1-37, wherein the secondary coating has an in situ glass transition temperature T_gGreater than 80 ℃.

Clause 39 of the present disclosure extends to:

the optical fiber of any of clauses 1-37, wherein the secondary coating has an in situ glass transition temperature T_gGreater than 100 ℃.

Clause 40 of the present disclosure extends to:

the optical fiber of any of clauses 1-39, wherein the normalized puncture load of the secondary coating is greater than 3.6x10^- ⁴g/μm²。

Clause 41 of the present disclosure extends to:

the optical fiber of any of clauses 1-39, wherein the normalized puncture load of the secondary coating is greater than 4.4x10^- ⁴g/μm²。

Clause 42 of the present disclosure extends to:

the optical fiber of any of clauses 1-41, whereinThe effective area of the optical fiber is greater than or equal to 90 μm²。

Clause 43 of the present disclosure extends to:

the optical fiber of any of clauses 1-41, wherein the effective area of the optical fiber is greater than or equal to 130 μm²。

Clause 44 of the present disclosure extends to:

the optical fiber of any of clauses 1-41, wherein the effective area of the optical fiber is greater than or equal to 145 μm²。

Clause 45 of the present disclosure extends to:

the optical fiber of any of clauses 1-44, wherein the scaled load transfer parameter P of the secondary coating₁the/P (scaled) is less than 0.97.

Clause 46 of the present disclosure extends to:

the optical fiber of any of clauses 1-44, wherein the secondary coating has a load transfer parameter P₁the/P is less than 0.0178.

Clause 47 of the present disclosure extends to:

the optical fiber of any of clauses 1-46, wherein the optical fiber has an attenuation of less than or equal to 0.160dB/km at a wavelength of 1550 nm.

Clause 48 of the present disclosure extends to:

the optical fiber of any of clauses 42 or 45-47, wherein the wire-mesh covered tube microbend loss of the optical fiber at 1550nm is less than 1.0 dB/km.

Clause 49 of the present disclosure extends to:

the optical fiber of any of clauses 44-47, wherein the wire-mesh covered tube microbending loss of the optical fiber at 1550nm is less than 1.0 dB/km.

Unless otherwise stated, it is not intended that any method described herein be construed as requiring that its steps be performed in a particular order. Thus, where a method claim does not actually recite an order to be followed by its steps or it does not otherwise specifically imply that the steps are to be limited to a specific order in the claims or specification, it is not intended that any particular order be implied.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. Since numerous modifications, combinations, sub-combinations and variations of the described embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and their equivalents.

63页详细技术资料下载

上一篇：一种医用注射器针头装配设备

下一篇：光学模尺寸转换器

Optical fiber cable with high optical fiber count

相关技术

网友询问留言