阅读说明：本技术 紫外光辐照低烟无卤电缆材料及其制备方法 (Ultraviolet light irradiation low-smoke halogen-free cable material and preparation method thereof ) 是由 武涛 刘悦 李同兵 钟荣栋 于 2019-12-05 设计创作，主要内容包括：本发明公开了紫外光辐照低烟无卤电缆材料的制备方法,使用了聚烯烃材料、阻燃剂A和阻燃剂B、光引发剂以及少量助剂,制备得到了具有优异性能的紫外光辐照低烟无卤电缆材料。实验测试结果表明,本发明制备得到的材料,即使厚度＞1mm、含有无机填充料或材料颜色较深时,也具有优异的阻燃性能和力学性能,且低烟无卤、工艺简单、成本较低,具有很好的实际应用价值。(The invention discloses a preparation method of an ultraviolet irradiation low-smoke halogen-free cable material, which uses a polyolefin material, a flame retardant A, a flame retardant B, a photoinitiator and a small amount of auxiliary agents to prepare the ultraviolet irradiation low-smoke halogen-free cable material with excellent performance. Experimental test results show that the material prepared by the invention has excellent flame retardant property and mechanical property even if the thickness is more than 1mm and the material contains inorganic filler or has dark color, and has the advantages of low smoke, no halogen, simple process, low cost and good practical application value.)

1. The preparation method of the ultraviolet light irradiation low-smoke halogen-free cable material is characterized by comprising the following steps:

step one, adding 15-20 parts by weight of ethylene-vinyl acetate copolymer, 15-20 parts by weight of polyethylene, 5-6 parts by weight of maleic anhydride graft, 30-35 parts by weight of flame retardant A, 10-15 parts by weight of flame retardant B, 0.5-1.5 parts by weight of photoinitiator, 0.01-0.1 part by weight of ultraviolet absorbent and 1-2 parts by weight of auxiliary agent into an internal mixer in sequence, and heating and stirring uniformly to obtain a mixed material;

step two, adding the mixed material obtained in the step one into an extruder, and extruding and granulating to obtain a granular material;

and step three, heating and irradiating the granular materials obtained in the step two by using a 0.6-1 KV ultraviolet irradiation instrument to obtain the ultraviolet irradiation low-smoke halogen-free cable material.

2. The preparation method of the ultraviolet light irradiation low-smoke zero-halogen cable material according to claim 1, wherein the VA content of the ethylene-vinyl acetate copolymer is 19-28 wt%.

3. The method for preparing the ultraviolet light irradiation low smoke zero halogen cable material according to claim 1, wherein the polyethylene is low density polyethylene and/or medium density polyethylene.

4. The method for preparing the ultraviolet light irradiation low smoke zero halogen cable material according to claim 1, wherein the maleic anhydride graft is selected from one or more of maleic anhydride grafted polyethylene, maleic anhydride grafted ethylene-vinyl acetate copolymer, and maleic anhydride grafted polyethylene octene co-elastomer.

5. The preparation method of the ultraviolet light irradiation low smoke zero halogen cable material according to claim 1, wherein the flame retardant A is one or more selected from the group consisting of phosphorus flame retardants, hydrated metal oxides, and nitrogen flame retardants.

6. The preparation method of the ultraviolet light irradiation low smoke zero halogen cable material according to claim 1, wherein the flame retardant B is a ferrocenyl flame retardant.

7. The method for preparing a low-smoke halogen-free cable material by ultraviolet irradiation according to claim 1, wherein the photoinitiator is selected from one or more of 2, 4-dihydroxy benzophenone, 4 '-dihydroxy benzophenone, Michler's ketone, thiopropoxy thioxanthone, isopropyl thioxanthone and anthraquinone.

8. The method for preparing a low-smoke halogen-free cable material by ultraviolet irradiation according to claim 1, wherein the ultraviolet absorber is one or more selected from the group consisting of 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2- (2-hydroxy-3, 5-ditert-pentyl-phenyl) benzotriazole and 2- (2-hydroxy-5-tert-octyl phenyl) benzotriazole.

9. The preparation method of the ultraviolet light irradiation low-smoke halogen-free cable material according to claim 1, wherein the weight ratio of the ethylene-vinyl acetate copolymer, the flame retardant B and the photoinitiator is 1: (0.6-0.8): (0.04-0.1).

10. Ultraviolet light irradiation low smoke zero halogen cable material, characterized in that, it is prepared by the preparation method of any one of claims 1-9.

Technical Field

The invention relates to the field of cable materials, in particular to an ultraviolet light irradiation low-smoke halogen-free cable material and a preparation method thereof.

Background

Polyolefin materials such as ethylene-vinyl acetate copolymers and polyethylene have been widely used as an insulating layer of a cable because of their excellent electrical insulating properties. In order to delay the ignition of the electric wire and the cable in case of fire, the cable material in the market generally adopts a mode of adding an inorganic flame retardant or adding an organic halogen-containing flame retardant, but has the problems of poor heat resistance or environmental pollution and the like, and the development of an environment-friendly low-smoke halogen-free cable material is urgent.

Meanwhile, in order to further enhance the mechanical properties of the cable material, the following three conventional crosslinking techniques are often adopted at present: high-energy radiation crosslinking, peroxide chemical crosslinking and silane crosslinking methods, but the high-energy radiation crosslinking equipment has higher investment and more complex maintenance; the peroxide chemical crosslinking requires high temperature and high pressure conditions, and the process and the control conditions are relatively complex; silane crosslinking involves hydrolysis reaction, and the product has poor stability and low pressure and temperature resistant grade. Therefore, the ultraviolet irradiation technology is increasingly paid more attention as a novel and efficient crosslinking technology. However, when the ultraviolet irradiation crosslinking is used at present, due to the limited ultraviolet penetration capability, when the material is too thick (more than 1mm) or contains fillers such as inorganic components and the like, the obtained material is difficult to be crosslinked completely after irradiation; meanwhile, the prior art has strict requirements on the color of the irradiated material, and when the material is too dark, the material is easy to absorb ultraviolet light and difficult to cure and crosslink. Therefore, it is highly desirable to develop an ultraviolet irradiation low smoke zero halogen cable material with excellent flame retardant property and mechanical property even if the cable material has a thickness of more than 1mm and contains inorganic filler or the material has a dark color.

Disclosure of Invention

In order to solve the technical problems, the first aspect of the invention provides a preparation method of an ultraviolet light irradiation low-smoke halogen-free cable material, which comprises the following steps:

step one, adding 15-20 parts by weight of ethylene-vinyl acetate copolymer, 15-20 parts by weight of polyethylene, 5-6 parts by weight of maleic anhydride graft, 30-35 parts by weight of flame retardant A, 10-15 parts by weight of flame retardant B, 0.5-1.5 parts by weight of photoinitiator, 0.01-0.1 part by weight of ultraviolet absorbent and 1-2 parts by weight of auxiliary agent into an internal mixer in sequence, and heating and stirring uniformly to obtain a mixed material;

step two, adding the mixed material obtained in the step one into an extruder, and extruding and granulating to obtain a granular material;

and step three, heating and irradiating the granular materials obtained in the step two by using a 0.6-1 KV ultraviolet irradiation instrument to obtain the ultraviolet irradiation low-smoke halogen-free cable material.

As a preferable technical scheme, the VA content of the ethylene-vinyl acetate copolymer is 19-28 wt%.

As a preferred technical solution, the polyethylene is low density polyethylene and/or medium density polyethylene.

As a preferred technical solution, the maleic anhydride graft is selected from one or more of maleic anhydride grafted polyethylene, maleic anhydride grafted ethylene-vinyl acetate copolymer, and maleic anhydride grafted polyethylene octene co-elastomer.

As a preferable technical scheme, the flame retardant A is selected from one or more of phosphorus flame retardants, hydrated metal oxides and nitrogen flame retardants.

As a preferable technical scheme, the flame retardant B is a ferrocenyl flame retardant.

As a preferred technical scheme, the photoinitiator is selected from one or more of 2, 4-dihydroxy benzophenone, 4 '-dihydroxy benzophenone, Michler's ketone, thiopropoxy thioxanthone, isopropyl thioxanthone and anthraquinone.

As a preferred technical scheme, the ultraviolet absorbent is selected from one or more of 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4 methoxy-5-sulfobenzophenone, 2- (2-hydroxy-3, 5-ditert-pentylphenyl) benzotriazole and 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole.

As a preferable technical scheme, the weight ratio of the ethylene-vinyl acetate copolymer, the flame retardant B and the photoinitiator is 1: (0.6-0.8): (0.04-0.1).

The second aspect of the invention provides an ultraviolet light irradiation low-smoke halogen-free cable material, which is prepared by the preparation method.

Has the advantages that: the ultraviolet irradiation low-smoke halogen-free cable material with excellent performance is prepared by mainly using the ethylene-vinyl acetate copolymer, the polyethylene, the maleic anhydride graft, the flame retardant, the photoinitiator, the ultraviolet absorbent and a small amount of auxiliary agent. Experimental test results show that the material prepared by the invention has excellent flame retardant property and mechanical property even if the thickness is more than 1mm and the material contains inorganic filler or has dark color, and has the advantages of low smoke, no halogen, simple process, low cost and good practical application value.

Detailed Description

The technical features of the technical solutions provided by the present invention are further clearly and completely described below with reference to the specific embodiments, and the scope of protection is not limited thereto.

The words "preferred", "more preferred", and the like, in the present invention refer to embodiments of the invention that may provide certain benefits, under certain circumstances. However, other embodiments may be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

In order to solve the technical problems, the first aspect of the invention provides an ultraviolet light irradiation low-smoke halogen-free cable material, which comprises the following preparation raw materials in parts by weight: 15-20 parts of ethylene-vinyl acetate copolymer, 15-20 parts of polyethylene, 5-6 parts of maleic anhydride graft, 30-35 parts of flame retardant A, 10-15 parts of flame retardant B, 0.5-1.5 parts of photoinitiator, 0.01-0.1 part of ultraviolet absorbent and 1-2 parts of auxiliary agent.

In a preferred embodiment, the ultraviolet light irradiation low smoke zero halogen cable material is prepared from the following raw materials in parts by weight: 17.5 parts of ethylene-vinyl acetate copolymer, 17.5 parts of polyethylene, 5.5 parts of maleic anhydride graft, 32.5 parts of flame retardant A, 12.5 parts of flame retardant B, 1 part of photoinitiator, 0.05 part of ultraviolet absorber and 1.5 parts of auxiliary agent.

The second aspect of the invention provides a preparation method of an ultraviolet light irradiation low-smoke halogen-free cable material, which comprises the following steps:

step one, adding 15-20 parts by weight of ethylene-vinyl acetate copolymer, 15-20 parts by weight of polyethylene, 5-6 parts by weight of maleic anhydride graft, 30-35 parts by weight of flame retardant A, 10-15 parts by weight of flame retardant B, 0.5-1.5 parts by weight of photoinitiator, 0.01-0.1 part by weight of ultraviolet absorbent and 1-2 parts by weight of auxiliary agent into an internal mixer in sequence, and heating and stirring uniformly to obtain a mixed material;

step two, adding the mixed material obtained in the step one into an extruder, and extruding and granulating to obtain a granular material;

and step three, heating and irradiating the granular materials obtained in the step two by using a 0.6-1 KV ultraviolet irradiation instrument to obtain the ultraviolet irradiation low-smoke halogen-free cable material.

In a preferred embodiment, the preparation method of the ultraviolet light irradiation low smoke zero halogen cable material comprises the following steps:

step one, according to parts by weight, sequentially adding 17.5 parts of ethylene-vinyl acetate copolymer, 17.5 parts of polyethylene, 5.5 parts of maleic anhydride graft, 32.5 parts of flame retardant A, 12.5 parts of flame retardant B, 1 part of photoinitiator, 0.05 part of ultraviolet absorbent and 1.5 parts of auxiliary agent into an internal mixer, and stirring at the stirring speed of 70r/min at 160 ℃ for 35min to obtain a mixed material;

step two, adding the mixed material obtained in the step one into an extruder, and extruding and granulating to obtain a granular material;

and step three, irradiating the granular materials obtained in the step two for 4s at 120 ℃ by using a 0.8KV ultraviolet irradiation instrument to obtain the ultraviolet irradiation low-smoke halogen-free cable material.

The r/min is a unit of rotational speed, which means revolutions per minute, i.e. revolutions per minute.

Ethylene-vinyl acetate copolymer

Ethylene-vinyl acetate copolymer (EVA) with the English name of ethylene-vinyl acetate copolymer (CAS number of 24937-78-8) is a high polymer material with good flexibility, optical property, low temperature resistance and good filler inclusion.

In a preferred embodiment, the VA content of the ethylene-vinyl acetate copolymer is 19 to 28 wt%.

In a more preferred embodiment, the ethylene-vinyl acetate copolymer has a VA content of 25 wt%.

The ethylene-vinyl acetate copolymer is Elvax series 350 of DuPont company in the United states, and the VA content is 25 wt%.

The content of VA, i.e., vinyl acetate, in the present invention is not particularly limited, and may be determined by a method known to those skilled in the art, for example, nuclear magnetic resonance.

Polyethylene

Polyethylene, known by the english name polyethylene (pe), is a thermoplastic resin obtained by polymerizing ethylene.

In a preferred embodiment, the polyethylene is a low density polyethylene and/or a medium density polyethylene.

In a more preferred embodiment, the polyethylene is a low density polyethylene.

The Low-Density Polyethylene, also called high-pressure Polyethylene, is a Low Density Polyethylene (LDPE) having good flexibility, extensibility, electrical insulation, transparency, easy processability and a certain air permeability. The low density polyethylene was purchased from exxon mobil corporation as LPZ 40.

Maleic anhydride grafts

Maleic anhydride graft, i.e. maleic anhydride molecules are grafted on polymer molecular chains by means of chemical reaction, so that a substance with the properties of both polymer molecules and maleic anhydride is obtained.

In a preferred embodiment, the maleic anhydride graft is selected from the group consisting of maleic anhydride grafted polyethylene, maleic anhydride grafted ethylene vinyl acetate copolymer, maleic anhydride grafted polyethylene octene co-elastomer.

In a more preferred embodiment, the maleic anhydride graft is maleic anhydride grafted polyethylene.

The maleic anhydride grafted polyethylene is HONEYWELL A-C573A.

Flame retardant

The flame retardant is a functional auxiliary agent capable of endowing flammable polymers with flame retardancy.

In a preferred embodiment, the flame retardant A is selected from one or more of phosphorus flame retardants, hydrated metal oxides and nitrogen flame retardants.

Examples of the phosphorus-based flame retardant include, but are not limited to: red phosphorus, ammonium polyphosphate, triphenylphosphine, tricresyl phosphate, tributyl phosphate, tris (2, 3-dibromopropyl) phosphate, aryl phosphates, toluene-diphenyl phosphate, 2-ethylhexyl) -diphenyl phosphate.

Examples of hydrated metal oxides include, but are not limited to: zinc oxide, aluminum hydroxide, magnesium hydroxide, siloxane compound, zinc stannate.

Examples of nitrogen-based flame retardants include, but are not limited to: melamine, melamine cyanurate, melamine phosphate.

In a more preferred embodiment, the flame retardant a is a phosphorus-based flame retardant.

In a further preferred embodiment, the phosphorus-based flame retardant is tricresyl phosphate.

The tricresyl phosphate has CAS number of 1330-78-5 and is purchased from Innovative chemical engineering technology Co., Ltd.

In a preferred embodiment, the flame retardant B is a ferrocenyl flame retardant.

In a more preferred embodiment, the ferrocenyl flame retardant is selected from one or more combinations of 1, 1' -ferrocene dimethanol, methyl ferrocene, ethyl ferrocene, propyl ferrocene, propionyl ferrocene, ferrocene carbonylpropionic acid.

In a more preferred embodiment, the ferrocenyl flame retardant is 1, 1' -ferrocenedimethanol.

The 1, 1' -ferrocene dimethanol has a CAS number of 1291-48-1 and is purchased from Shanghai Jiang chemical engineering Co., Ltd.

Photoinitiator

The photoinitiator, also called photosensitizer and light curing agent, is a compound which can absorb energy with certain wavelength in an ultraviolet region (250-420 nm) so as to initiate polymerization, crosslinking and curing of monomers.

In a preferred embodiment, the photoinitiator is selected from one or more combinations of 2, 4-dihydroxybenzophenone, 4 '-dihydroxybenzophenone, benzophenone, Michler's ketone, thiopropoxythioanthrone, isopropylthioxanthone, anthraquinone.

In a more preferred embodiment, the photoinitiator is 2, 4-dihydroxybenzophenone.

The 2, 4-dihydroxy benzophenone with CAS number of 131-56-6 is purchased from Guanao chemical Co., Ltd, Guangzhou city.

When the prior art uses ultraviolet irradiation for crosslinking, because the penetration capacity of ultraviolet light is limited, when the material is too thick (more than 1mm) or the material contains fillers such as inorganic components and the like, the obtained material is difficult to be completely crosslinked after irradiation; meanwhile, the prior art has strict requirements on the color of the irradiated material, and when the material is too dark, the material is easy to absorb ultraviolet light and difficult to cure and crosslink. How to improve the crosslinking capacity of the material after ultraviolet irradiation is a great problem to be solved by the inventor.

The inventor finds that when a ferrocenyl flame retardant, particularly 1, 1 '-ferrocene dimethanol, is added into a system, the flame retardant performance of the prepared cable material is further improved, and the inventor considers that a certain amount of free radicals can be introduced into the surface of the material by virtue of a special sandwich cyclopentadiene structure in the 1, 1' -ferrocene dimethanol, so that a continuous and compact carbon layer is formed on the surface of the material; and the flame retardant A tricresyl phosphate is cooperated to disturb the degradation chain reaction of the high polymer material, so that the dehydration and carbon formation of the high polymer material are further promoted, the heat transfer is isolated, and the combustible gases such as oxygen and the like are prevented from entering the inner layer of the material, thereby achieving the effects of flame retardance and smoke suppression.

In a preferred embodiment, the weight ratio of the ethylene-vinyl acetate copolymer, the flame retardant B and the photoinitiator is 1: (0.6-0.8): (0.04-0.1).

In a more preferred embodiment, the weight ratio of the ethylene-vinyl acetate copolymer, the flame retardant B and the photoinitiator is 1: 0.7: 0.06.

the inventor unexpectedly finds that the flame retardant 1, 1' -ferrocene dimethanol is introduced, and the weight ratio of the added ethylene-vinyl acetate copolymer, the flame retardant B and the photoinitiator is 1: (0.6-0.8): (0.04-0.08), the prepared cable material is remarkably improved in performance in all aspects after crosslinking, and has excellent crosslinking performance even if the thickness of the material is more than 1mm and the material contains inorganic fillers or is dark in color. The inventor conjectures that the possible reason is that after the ultraviolet light irradiation, the photoinitiator absorbs the irradiation energy to obtain high energy, the high energy is transited from a ground state to an excited state, and the photoinitiator carries out hydrogen abstraction on polymer materials such as ethylene-vinyl acetate copolymer to generate free radicals, and the obtained free radicals further initiate the cross-linking reaction of molecules in the materials; however, when the thickness of the material is larger than 1mm and the material contains inorganic filler or has a dark color, the free radicals generated by the photoinitiator after absorbing the illumination energy are not enough to initiate the cross-linking reaction of the molecules in the material, and the flame retardant 1, 1' -ferrocenedimethanol uniformly existing in the system can introduce a proper amount of free radicals into the material under the irradiation of ultraviolet light to initiate the cross-linking reaction between the molecules in the materials such as ethylene-vinyl acetate copolymer, so that the integral tensile strength and elongation at break of the material after cross-linking are obviously improved. However, when the flame retardant 1, 1' -ferrocene dimethanol is too much, too much free radicals are introduced into the system, and the crosslinking performance of the material is damaged; when the amount of the photoinitiator is too large, the curing speed difference between the surface and the interior of the material is too large, and the ultraviolet radiation crosslinking of the material is hindered.

Ultraviolet absorber

An ultraviolet absorber is an agent that maintains the structural stability of a polymeric material when exposed to light.

In a preferred embodiment, the UV absorber is selected from the group consisting of 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2- (2-hydroxy-3, 5-ditert-pentylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, and combinations of one or more thereof.

In a more preferred embodiment, the UV absorber is 2-hydroxy-4-methoxy-5-sulfobenzophenone.

The 2-hydroxy-4-methoxy-5-sulfobenzophenone has a CAS number of 4065-45-6 and is purchased from Tiaoh chemical Co., Ltd.

Auxiliary agent

The auxiliaries are not particularly limited in the present invention, and various auxiliaries known to those skilled in the art, such as pigments, antioxidants, antistatic agents, fillers, can be selected according to the actual circumstances.

The present invention will now be described in detail by way of examples, and the starting materials used are commercially available unless otherwise specified.