阅读说明：本技术 树脂组合物、树脂被覆材料、汽车用线束和汽车用线束的制造方法 (Resin composition, resin coating material, automotive wire harness, and method for producing automotive wire harness ) 是由 高桥贤司 泽田由香 押野贵志 铃木裕 内山泰治 大菅秀幸 于 2018-07-03 设计创作，主要内容包括：一种树脂组合物、汽车用线束和汽车用线束的制造方法,相对于乙烯-乙酸乙烯酯共聚物(A)90质量份～100质量份,所述树脂组合物含有溴系阻燃剂(B)15质量份～30质量份、三氧化锑(C)5质量份～15质量份、苯并咪唑系抗老化剂(D)6质量份～12质量份、酚系抗老化剂(E)2质量份～4质量份、硫醚系抗老化剂(F)2质量份～4质量份、铜抑制剂(G)0.5质量份～2质量份和交联助剂(H)3质量份～6质量份。(A resin composition comprising 15 to 30 parts by mass of a brominated flame retardant (B), 5 to 15 parts by mass of antimony trioxide (C), 6 to 12 parts by mass of a benzimidazole-based aging inhibitor (D), 2 to 4 parts by mass of a phenolic aging inhibitor (E), 2 to 4 parts by mass of a thioether-based aging inhibitor (F), 0.5 to 2 parts by mass of a copper inhibitor (G), and 3 to 6 parts by mass of a crosslinking assistant (H), 90 to 100 parts by mass of an ethylene-vinyl acetate copolymer (A).)

1. A resin composition comprising, based on 90 to 100 parts by mass of an ethylene-vinyl acetate copolymer (A), 15 to 30 parts by mass of a brominated flame retardant (B), 5 to 15 parts by mass of antimony trioxide (C), 6 to 12 parts by mass of a benzimidazole-based antiaging agent (D), 2 to 4 parts by mass of a phenolic antiaging agent (E), 2 to 4 parts by mass of a thioether-based antiaging agent (F), 0.5 to 2 parts by mass of a copper inhibitor (G), and 3 to 6 parts by mass of a crosslinking assistant (H).

2. The resin composition according to claim 1, wherein the resin composition contains 1 to 10 parts by mass of the maleic acid-modified polyethylene (I).

3. The resin composition according to claim 1 or 2, wherein the resin composition is used for wiring harnesses for automobiles.

4. A resin coating material obtained by crosslinking the resin composition according to any one of claims 1 to 3.

5. A wire harness for an automobile, comprising a layer composed of the resin covering material according to claim 4.

6. A method for producing an automotive wire harness, comprising a step of irradiating a resin composition with an electron beam of 80kGy to 250kGy, the resin composition containing 90 to 100 parts by mass of an ethylene-vinyl acetate copolymer (A), 15 to 30 parts by mass of a bromine-based flame retardant (B), 5 to 15 parts by mass of antimony trioxide (C), 6 to 12 parts by mass of a benzimidazole-based aging inhibitor (D), 2 to 4 parts by mass of a phenol-based aging inhibitor (E), 2 to 4 parts by mass of a thioether-based aging inhibitor (F), 0.5 to 2 parts by mass of a copper inhibitor (G), and 3 to 6 parts by mass of a crosslinking assistant (H).

Technical Field

The present invention relates to a resin composition, a resin coating material, an automotive wire harness, and a method for manufacturing an automotive wire harness.

Background

Insulated wires having flame retardancy are widely used in various white home appliances, OA equipment, and the like. Further, insulated wires used in automobiles and the like are also required to have various properties such as flame retardancy and heat resistance. Heretofore, a resin composition for realizing an insulated wire having flame retardancy and heat resistance by using it as a covering material for a conductor has been studied, and many reports have been made.

For example, patent document 1 describes a flame-retardant resin composition which is used as a coating material for a conductor, and which can provide an insulated wire having excellent heat resistance life, flame retardancy, and coexistence with polyvinyl chloride (PVC), and which does not cause problems such as elution of heavy metal compounds and generation of a large amount of smoke and corrosive gas when disposed of, for example, in landfills and incinerations. The flame-retardant resin composition comprises, per 100 parts by mass of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 10 to less than 40% by mass or a mixture of an ethylene-vinyl acetate copolymer and a polyolefin, 50 to 160 parts by mass of a metal hydrate, 2 to 10 parts by mass of a phenolic antioxidant, 10 to 25 parts by mass of a benzimidazole antioxidant, and 0to 10 parts by mass of a thioether antioxidant.

Patent document 2 describes a resin composition which is used as a covering material for a conductor to obtain an insulated wire excellent in heat resistance, mechanical properties, flame retardancy, and appearance. The resin composition contains 10 to 100 parts by mass of a thioether antioxidant and 10 to 120 parts by mass of a benzimidazole antioxidant per 100 parts by mass of a resin component composed of a polyolefin resin and/or an ethylene copolymer composed of ethylene and a substituted ethylene. Patent document 3 describes a resin composition which is used as a covering material for a conductor to obtain an insulated wire exhibiting high flame retardancy, low temperature properties, and thermal aging resistance. The resin composition comprises 15 to 80 parts by mass of a bromine-based flame retardant other than polybromophenyl ether and polybromobiphenyl, 10 to 70 parts by mass of antimony trioxide and 10 to 60 parts by mass of a metal hydrate, per 100 parts by mass of a resin component mainly composed of an ethylene copolymer.

Patent document 4 describes a composition for an insulated wire coating material, which is used as a conductor coating material to obtain an insulated wire having excellent heat resistance and mechanical properties. The composition for an insulated wire covering material comprises a water-crosslinkable polyolefin obtained by modifying a polyolefin with a silane coupling agent, an unmodified polyolefin, a modified polyolefin obtained by modifying a functional group, a flame retardant containing a brominated flame retardant, a crosslinking catalyst, a phenolic antioxidant, zinc sulfide, or zinc oxide and an imidazole compound. Patent document 5 describes an insulating resin composition which is used as a covering material for a conductor, thereby providing an insulated wire having excellent flexibility, water-stopping performance, and heat resistance. The insulating resin composition contains two specific copolymers and a flame retardant at specific ratios.

Disclosure of Invention

Problems to be solved by the invention

With the development of hybrid vehicles and the like in recent years, insulated wires used in vehicles and the like are required to have more excellent characteristics than ever, such as flexibility, hardness, degree of crosslinking, abrasion resistance, flame retardancy, cold resistance, and heat resistance. For example, taking heat resistance as an example, there is an increasing demand for insulated wires that satisfy the requirements of heat resistance class D of 150 ℃ in automotive standards (JASO) D624 (2015) or heat resistance class D in ISO 6722 (2006).

In view of the above circumstances, an object of the present invention is to provide a resin composition which is used for forming a resin coating material layer of an insulated electric wire, and which can provide an insulated electric wire exhibiting desired excellent characteristics in all of flexibility, hardness, crosslinking degree, abrasion resistance, flame retardancy, cold resistance and heat resistance, and which is also excellent in processing efficiency. Another object of the present invention is to provide a resin coating material which can be used as a coating material for a conductor or the like to realize an insulated electric wire exhibiting desired excellent characteristics in all of flexibility, hardness, crosslinking degree, abrasion resistance, flame retardancy, cold resistance and heat resistance. Another object of the present invention is to provide an automotive wire harness having a layer made of the resin covering material, and a method for manufacturing the automotive wire harness.

Means for solving the problems

The present inventors have conducted studies to solve the above problems, and as a result, have found that a resin composition containing a specific amount of each of an ethylene-vinyl acetate copolymer, a specific flame retardant, two or more specific antioxidants, a copper inhibitor and a crosslinking assistant is prepared, and that the composition is difficult to adhere to a processing machine (excellent processing adhesion) in the preparation of the resin composition, and the amount of the composition remaining in the processing machine can be suppressed, and that an insulated electric wire exhibiting desired excellent characteristics in all of flexibility, hardness, crosslinking degree, abrasion resistance, flame retardancy, cold resistance and heat resistance can be obtained by applying the composition to the surface of a conductor or the like and crosslinking the composition. The present invention has been completed based on this technical idea.

That is, the above problems are solved by the following means.

<1>

A resin composition comprising, based on 90 to 100 parts by mass of an ethylene-vinyl acetate copolymer (A), 15 to 30 parts by mass of a brominated flame retardant (B), 5 to 15 parts by mass of antimony trioxide (C), 6 to 12 parts by mass of a benzimidazole-based antiaging agent (D), 2 to 4 parts by mass of a phenolic antiaging agent (E), 2 to 4 parts by mass of a thioether-based antiaging agent (F), 0.5 to 2 parts by mass of a copper inhibitor (G), and 3 to 6 parts by mass of a crosslinking assistant (H).

<2>

The resin composition according to <1>, which comprises 1 to 10 parts by mass of the maleic acid-modified polyethylene (I).

<3>

The resin composition according to <1> or <2>, wherein the resin composition is used for a wiring harness for an automobile.

<4>

A resin coating material obtained by crosslinking the resin composition according to any one of <1> to <3 >.

<5>

A wire harness for an automobile, comprising a layer composed of the resin covering material of <4 >.

<6>

A method for producing an automotive wire harness, comprising a step of irradiating a resin composition with an electron beam of 80kGy to 250kGy, the resin composition containing 90 to 100 parts by mass of an ethylene-vinyl acetate copolymer (A), 15 to 30 parts by mass of a bromine-based flame retardant (B), 5 to 15 parts by mass of antimony trioxide (C), 6 to 12 parts by mass of a benzimidazole-based aging inhibitor (D), 2 to 4 parts by mass of a phenol-based aging inhibitor (E), 2 to 4 parts by mass of a thioether-based aging inhibitor (F), 0.5 to 2 parts by mass of a copper inhibitor (G), and 3 to 6 parts by mass of a crosslinking assistant (H).

ADVANTAGEOUS EFFECTS OF INVENTION

The resin composition of the present invention is excellent in processing adhesiveness, and can be used as a coating material for an insulated wire, thereby obtaining an insulated wire exhibiting desired excellent characteristics in all of flexibility, hardness, degree of crosslinking, abrasion resistance, flame retardancy, cold resistance and heat resistance. The resin coating material of the present invention is used as a coating material for a conductor or the like, and thus an insulated electric wire exhibiting desired excellent characteristics in all of flexibility, hardness, crosslinking degree, abrasion resistance, flame retardancy, cold resistance and heat resistance can be obtained. The automotive wiring harness of the present invention has a layer composed of the resin coating material of the present invention, and exhibits desirable excellent characteristics in all of flexibility, hardness, degree of crosslinking, abrasion resistance, flame retardancy, cold resistance, and heat resistance. According to the method for manufacturing an automotive wire harness of the present invention, an automotive wire harness having the above excellent properties can be obtained.

Detailed Description

< resin composition >

The resin composition of the present invention contains, relative to 90 to 100 parts by mass of an ethylene-vinyl acetate copolymer (A), 15 to 30 parts by mass of a bromine-based flame retardant (B) and 5 to 15 parts by mass of antimony trioxide (C) as flame retardants, and also contains 6 to 12 parts by mass of a benzimidazole-based aging inhibitor (D), 2 to 4 parts by mass of a phenol-based aging inhibitor (E), 2 to 4 parts by mass of a thioether-based aging inhibitor (F), 0.5 to 2 parts by mass of a copper inhibitor (G), and 3 to 6 parts by mass of a crosslinking assistant (H) as aging inhibitors. Hereinafter, the automotive harness may be simply referred to as "harness". In addition, each component may not be described with a reference numeral. For example, the ethylene-vinyl acetate copolymer (a) may be abbreviated as "ethylene-vinyl acetate copolymer".

The resin composition of the present invention may contain 1 kind of all the components, including optional components described later, or may contain 2 or more kinds of the components in combination.

(ethylene-vinyl acetate copolymer (A))

The resin composition of the present invention contains 90 to 100 parts by mass of an ethylene-vinyl acetate copolymer (a). When the content of the ethylene-vinyl acetate copolymer (a) is less than 90 parts by mass, the degree of crosslinking and flame retardancy of the insulated wire may be reduced. On the other hand, when the content of the ethylene-vinyl acetate copolymer (a) exceeds 100 parts by mass, the excellent flexibility of the insulated wire can be maintained, but the processing adhesiveness and the mechanical strength are reduced. The polymerization form of the ethylene-vinyl acetate copolymer used in the present invention may be any of block, random and graft. The content of the vinyl acetate component in the ethylene-vinyl acetate copolymer is preferably 10 to 30% by mass, and particularly preferably 10 to 20% by mass. When the content ratio of the vinyl acetate component is within the above range, the resin coating material produced using the resin composition of the present invention can maintain sufficient flexibility, while the resin composition is less likely to adhere to a processing machine (excellent processing adhesion), and the amount of the composition remaining in the processing machine can be suppressed, and the flame retardancy of the insulated electric wire can be further improved. The content of the vinyl acetate component can be determined from the mass ratio of the raw materials (monomers) during synthesis, for example.

The ethylene-vinyl acetate copolymer used in the present invention can be synthesized by a conventional method. Further, commercially available products may be used. Specific examples of commercially available products include EVAFLEX V5274, EVAFLEX V422 and EVAFLEX EV40LX (both trade names) manufactured by Du Pont-Mitsui Polychemicals.

The Melt Flow Rate (MFR) of the ethylene-vinyl acetate copolymer is preferably from 0.1g/10 min to 10g/10 min (load 2.16kg, temperature 190 ℃ C.), more preferably from 0.5g/10 min to 5g/10 min.

When an ethylene-vinyl acetate copolymer having an excessively low melt flow rate is used, the load on kneading equipment and an extruder may be increased during the production of a resin composition or during the production of a strand.

On the other hand, when an ethylene-vinyl acetate copolymer having an excessively high melt flow rate is used, the load on the extruder as a molding device for a strand is reduced, but the dispersibility of each component in the resin composition may be reduced.

(brominated flame retardant (B))

The resin composition of the present invention contains 15 to 30 parts by mass of the brominated flame retardant (B). When the content of the bromine-based flame retardant (B) is less than 15 parts by mass, sufficient flame retardancy of the insulated wire cannot be obtained. On the other hand, when the content of the bromine-based flame retardant (B) exceeds 30 parts by mass, the flexibility, cold resistance and mechanical strength of the insulated wire are lowered, and the heat resistance and abrasion resistance are lowered.

The bromine-containing flame retardant used in the present invention is a bromine-containing compound. That is, the resin composition of the present invention contains a bromine-containing compound as a flame retardant. In addition, the brominated flame retardants used in the present invention do not include polybromophenyl ether and polybromobiphenyl. As the bromine-based flame retardant, for example, an organic bromine-containing flame retardant such as brominated N, N '-ethylene-bis-phthalimide or a compound derived therefrom (these are collectively referred to as "brominated N, N' -ethylene-bis-phthalimide compound"), N '-bis (bromophenyl) terephthalamide or a compound derived therefrom (these are collectively referred to as "N, N' -bis (bromophenyl) terephthalamide compound"), brominated bisphenol or a compound derived therefrom (these are collectively referred to as "brominated bisphenol compound"), 1, 2-bis (bromophenyl) alkane, or the like can be used. Among them, for example, brominated N, N' -ethylene bis phthalimide represented by the following structural formula 1 and/or 1, 2-bis (bromophenyl) ethane represented by the following structural formula 2 are preferably used.

By using brominated N, N' -ethylene bis-phthalimide and/or 1, 2-bis (bromophenyl) alkane as a flame retardant, a resin coating material that hardly undergoes blooming can be formed.

In the present invention, the use of polybromophenyl ether or polybromobiphenyl as a flame retardant is avoided because there is a possibility that blooming may occur drastically. In addition, in the case of using a chlorine-based flame retardant, the same problem of blooming may occur, and therefore, the resin composition of the present invention preferably does not contain a chlorine-based flame retardant.

[ CHEM 1 ]

Structural formula 1

[ CHEM 2 ]

Structural formula 2

[ in the formula, m and n are integers of 1-5 respectively. ]

Commercially available bromine-based flame retardants can also be used in the present invention. Examples of commercially available products include SAYTEX 8010 (trade name) manufactured by Albemarle corporation.

(antimony trioxide (C))

The resin composition of the present invention contains 5 to 15 parts by mass of antimony trioxide (C). When the content of antimony trioxide (C) is less than 5 parts by mass, the flame retardancy of the insulated wire is significantly reduced. When the content of antimony trioxide (C) exceeds 15 parts by mass, the flexibility, low temperature property and mechanical strength of the insulated wire are lowered, and the heat resistance and abrasion resistance are lowered.

The present invention may also use antimony trioxide which is commercially available. Examples of commercially available products include PATOX-C (trade name) manufactured by Nippon concentrate Co.

(benzimidazole-based antiaging agent (D))

The resin composition of the present invention contains 6 to 12 parts by mass of a benzimidazole antioxidant (D) (benzimidazole antioxidant (D)). That is, the resin composition of the present invention contains a specific amount of a benzimidazole compound (compound having a benzimidazole skeleton) as an antioxidant. When the content of the benzimidazole type antioxidant (D) is less than 6 parts by mass, the heat resistance of the insulated wire is remarkably lowered. On the other hand, when the content of the benzimidazole-based aging inhibitor (D) exceeds 12 parts by mass, the flame retardancy of the insulated wire is remarkably reduced, and the abrasion resistance is reduced.

Examples of the benzimidazole-based antioxidant include 2-sulfanylbenzimidazole, 2-sulfanylmethylbenzimidazole, 4-sulfanylmethylbenzimidazole, 5-sulfanylmethylbenzimidazole, and zinc salts thereof, and 2-sulfanylbenzimidazole is preferable.

Commercially available benzimidazole-based antioxidants can also be used in the present invention. Examples of commercially available products include NOCRAC MBZ (trade name) manufactured by shinkansen chemical company, inc.

(phenol type antiaging agent (E))

The resin composition of the present invention contains 2 to 4 parts by mass of the phenolic antioxidant (E) (phenolic antioxidant (E)). That is, the resin composition of the present invention contains a specific amount of a phenolic compound (compound having a phenol skeleton) as an aging inhibitor. When the content of the phenolic antioxidant (E) is less than 2 parts by mass, the heat resistance of the insulated wire is remarkably lowered. On the other hand, when the content of the phenolic antioxidant (E) exceeds 4 parts by mass, the flame retardancy and abrasion resistance of the insulated wire are lowered, or blooming occurs.

Examples of the phenol-based antiaging agent include triethylene glycol-bis (3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate), 1, 6-hexanediol-bis (3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate), pentaerythritol tetrakis (3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate), octadecyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3, 5-trimethyl-2, 4, 6-tris (3, 5-di-tert-butyl-4-hydroxybenzyl) benzene, tris (3, 5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, and mixtures thereof, And isooctyl 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, and among these, from the viewpoint of imparting high heat resistance to automotive wiring harnesses, those having 2 or more 3, 5-di-tert-butyl-4-hydroxyphenyl groups or 3, 5-di-tert-butyl-4-hydroxybenzyl groups are preferable, and tris (3, 5-di-tert-butyl-4-hydroxybenzyl) isocyanurate and pentaerythritol tetrakis (3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate) are particularly preferable.

Commercial phenol-based antioxidants can also be used in the present invention. Examples of commercially available products include IRGANOX 1010 (trade name) manufactured by BASF corporation.

(thioether-based antiaging agent (F))

The resin composition of the present invention contains 2 to 4 parts by mass of the thioether antioxidant (F) (thioether antioxidant (F)). That is, the resin composition of the present invention contains a specific amount of a thioether compound (a compound having a thioether bond) as an aging inhibitor. When the content of the thioether-based aging inhibitor (F) is less than 2 parts by mass, the heat resistance of the insulated wire is significantly reduced. On the other hand, when the content of the thioether-based aging inhibitor (F) exceeds 4 parts by mass, the flame retardancy and abrasion resistance of the insulated wire are reduced, or blooming occurs in the insulated wire.

Examples of the thioether-based antioxidant include dilauryl 3,3 ' -thiodipropionate, dimyristyl 3,3 ' -thiodipropionate, distearyl 3,3 ' -thiodipropionate, and pentaerythritol tetrakis (3-laurylthiopropionate), and among these, pentaerythritol tetrakis (3-laurylthiopropionate) is preferred in view of imparting high heat resistance to the composition and the insulated wire.

The present invention may also use a commercially available thioether-based antiaging agent. Examples of commercially available products include ADK STAB AO-412S (trade name) manufactured by ADEKA.

The heat resistance, flame retardancy, and abrasion resistance of the resin coating material of the present invention or the insulated wire having a layer made of the resin coating material can be further improved by combining a benzimidazole type aging inhibitor, a phenol type aging inhibitor, and a thioether type aging inhibitor.

(copper inhibitor (G))

The resin composition of the present invention contains 0.5 to 2 parts by mass of a copper inhibitor (G) (metal-inactivating agent (G)). When the content of the copper inhibitor (G) is less than 0.5 parts by mass, the oxidation degradation inhibiting ability of the aging inhibitor is lowered by contact with metal ions such as copper, and the heat resistance of the insulated wire is lowered. On the other hand, when the content of the copper inhibitor (G) exceeds 2 parts by mass, the flame retardancy of the insulated wire may be lowered.

Examples of the copper inhibitor (G) include triazole compounds, N' -diacylhydrazine compounds, dihydrazide compounds, and the like. Examples of the copper inhibitor include the heavy metal inerting agent ADK STAB CDA series manufactured by ADEKA corporation. Specific examples thereof include CDA-1, CDA-6 and CDA-10 (all trade names). Further, IRGANOX MD1024 (trade name) manufactured by BASF corporation may be mentioned. Particularly preferred are CDA-10[ N, N-bis [3- (3, 5-di-t-butyl-4-hydroxyphenyl) propionyl ] hydrazine ] and IRGANOX MD1024, from the viewpoint of having a high heat resistance-improving effect.

(crosslinking assistant (H))

The resin composition of the present invention contains 3 to 6 parts by mass of a crosslinking assistant (H). When the content of the crosslinking assistant (H) is less than 3 parts by mass, crosslinking does not sufficiently proceed, and the mechanical strength, flame retardancy, and heat resistance of the insulated wire are lowered. On the other hand, when the content of the crosslinking assistant (H) exceeds 6 parts by mass, the crosslinking density becomes high, and the flexibility of the insulated wire is lowered. In addition, when a resin composition is prepared, the composition is easy to slip in a processing machine, and a mixing time for dispersing the composition is required.

Commercially available crosslinking aids may also be used in the present invention. An example of a commercially available product is オグモント T200 (trade name) manufactured by Ninghamu chemical industries, Ltd.

(maleic acid-modified polyethylene (I))

The resin composition of the present invention preferably contains 1 to 10 parts by mass, more preferably 5 to 10 parts by mass of maleic acid-modified polyethylene (I). When the content of the maleic acid-modified polyethylene (I) is within the above range, the insulated wire having the resin coating material produced using the resin composition of the present invention has sufficient flexibility. Furthermore, since the resin composition is hard to adhere to a processing machine (excellent in processing adhesion), the amount of the composition remaining in the processing machine can be suppressed, and the abrasion resistance of the insulated wire can be further improved by improving the compatibility between the resin in the composition and the filler.

(additives)

The resin composition of the present invention may be appropriately compounded with various additives such as a lubricant, an ultraviolet absorber, a dispersant, a plasticizer, a filler, a pigment and the like as needed within a range not to impair the effects of the present invention. Examples of such additives include zinc compounds. Specific examples of the zinc compound include zinc sulfide and zinc oxide. In the resin composition of the present invention, the content of the lubricant is preferably 0.5 to 2 parts by mass.

The resin composition of the present invention may contain a metal hydrate such as aluminum hydroxide or magnesium hydroxide, and the content thereof is preferably 5 parts by mass or less, and more preferably 3 parts by mass or less, relative to 90 parts by mass to 100 parts by mass of the ethylene-vinyl acetate copolymer (a). This is because, when the content of the metal hydrate is too large, flexibility, abrasion resistance, mechanical strength, and cold resistance of the insulated wire are reduced.

The composition of the present invention contains a resin. The composition of the present invention preferably contains, per 100 parts by mass of the resin content, 15 to 30 parts by mass of the bromine-based flame retardant (B) and 5 to 15 parts by mass of antimony trioxide (C) as flame retardants, 6 to 12 parts by mass of the benzimidazole-based antioxidant (D), 2 to 4 parts by mass of the phenol-based antioxidant (E), and 2 to 4 parts by mass of the thioether-based antioxidant (F), and further contains 0.5 to 2 parts by mass of the copper inhibitor (G), and 3 to 6 parts by mass of the crosslinking assistant (H).

In the composition of the present invention, the resin contains an ethylene-vinyl acetate copolymer (a). The resin preferably contains maleic acid-modified polyethylene, and may contain low-density polyethylene.

The content of the ethylene-vinyl acetate copolymer (a) in the resin is 90 to 100 mass%.

The resin is preferably (1) an ethylene-vinyl acetate copolymer, (2) a combination of an ethylene-vinyl acetate copolymer and a maleic acid-modified polyethylene, or (3) a combination of an ethylene-vinyl acetate copolymer, a maleic acid-modified polyethylene, and a low-density polyethylene.

In the above (2), the content of the maleic acid-modified polyethylene in the resin is preferably 1 to 10% by mass. In the above (3), the total content of the maleic acid-modified polyethylene and the low-density polyethylene in the resin is preferably 1 to 10% by mass.

Specifically, the composition of the present invention is preferably a resin composition for a coating material layer of an insulated wire,

it contains resin, flame retardant, anti-aging agent, copper inhibitor and crosslinking assistant,

the resin is composed of (1) an ethylene-vinyl acetate copolymer, (2) a combination of an ethylene-vinyl acetate copolymer and a maleic acid-modified polyethylene, or (3) a combination of an ethylene-vinyl acetate copolymer, a maleic acid-modified polyethylene and a low-density polyethylene,

when the ethylene-vinyl acetate copolymer is 90 to 100 parts by mass and the maleic acid-modified polyethylene is contained, the content of the maleic acid-modified polyethylene is 1 to 10 parts by mass, and the total amount of the resin is 100 parts by mass,

the resin composition contains 15 to 30 parts by mass of a bromine-based flame retardant, 5 to 15 parts by mass of antimony trioxide, 6 to 12 parts by mass of a benzimidazole-based aging inhibitor, 2 to 4 parts by mass of a phenol-based aging inhibitor, 2 to 4 parts by mass of a thioether-based aging inhibitor, 0.5 to 2 parts by mass of a copper inhibitor, and 3 to 6 parts by mass of a crosslinking assistant, per 100 parts by mass of the total amount of the resin.

< method for producing resin composition >

The resin composition of the present invention can be obtained as follows: the above components (A) to (H) are blended, and if necessary, the above arbitrary components are blended and melt-kneaded by a commonly used kneading apparatus such as a batch kneader such as a roll, a kneader, or a Banbury mixer, or a twin-screw extruder.

< wire harness for automobile >

The automotive wiring harness of the present invention has a layer made of a resin coating material obtained by crosslinking the resin composition of the present invention on the surface of a conductor (including a conductor bundle and a fiber core). The automotive wire harness of the present invention may have an intermediate layer and a shielding layer between the conductor and the layer made of the resin coating material.

< method for producing automotive wire harness >

The method for producing an automotive wiring harness of the present invention comprises a step of irradiating an electronic beam of 80kGy to 250kGy with a resin composition for an automotive wiring harness, which contains 90 to 100 parts by mass of an ethylene-vinyl acetate copolymer (A), 15 to 30 parts by mass of a bromine-based flame retardant (B), 5 to 15 parts by mass of antimony trioxide (C), 6 to 12 parts by mass of a benzimidazole-based aging inhibitor (D), 2 to 4 parts by mass of a phenol-based aging inhibitor (E), 2 to 4 parts by mass of a thioether-based aging inhibitor (F), 0.5 to 2 parts by mass of a copper inhibitor (G), and 3 to 6 parts by mass of a crosslinking assistant (H).

The automotive wiring harness of the present invention can be produced by extrusion coating the resin composition of the present invention around a conductor. The conductor may be a single wire or a twisted wire, a bare wire, or a conductor coated with tin plating or enamel. Examples of the metal material forming the conductor include soft copper, copper alloy, and aluminum. The thickness of the layer made of the resin coating material formed around the conductor is not particularly limited, and is usually about 0.15mm to 5 mm.

The conductor diameter, the material of the conductor, the thickness of the coating layer, and the like are not particularly limited and are appropriately set according to the application. The step of irradiating with an electron beam is preferably performed after the extrusion coating. The electron beam crosslinking can be carried out by a usual method and conditions without limitation. The irradiation amount of the electron beam is preferably 50kGy to 450kGy, more preferably 80kGy to 250kGy, further preferably 80kGy to 200kGy, and particularly preferably 80kGy to 160 kGy.

Further, the conductor may have a multilayer structure in which an intermediate layer, a shielding layer, or the like is provided between the conductor and the coating layer, or between the coating layer and the coating layer.

The method for manufacturing an automotive wire harness according to the present invention is preferably a method for manufacturing an automotive wire harness, including the steps of: the resin composition is extruded and coated on a conductor to form a coating material layer, and then is irradiated with an electron beam of 80kGy to 250kGy,

the resin composition comprises a resin, a flame retardant, an antiaging agent, a copper inhibitor and a crosslinking assistant,

the resin is composed of (1) an ethylene-vinyl acetate copolymer, (2) a combination of an ethylene-vinyl acetate copolymer and a maleic acid-modified polyethylene, or (3) a combination of an ethylene-vinyl acetate copolymer, a maleic acid-modified polyethylene and a low-density polyethylene,

when the ethylene-vinyl acetate copolymer is 90 to 100 parts by mass and the maleic acid-modified polyethylene is contained, the content of the maleic acid-modified polyethylene is 1 to 10 parts by mass, and the total amount of the resin is 100 parts by mass,

the resin composition contains 15 to 30 parts by mass of a bromine-based flame retardant, 5 to 15 parts by mass of antimony trioxide, 6 to 12 parts by mass of a benzimidazole-based aging inhibitor, 2 to 4 parts by mass of a phenol-based aging inhibitor, 2 to 4 parts by mass of a thioether-based aging inhibitor, 0.5 to 2 parts by mass of a copper inhibitor, and 3 to 6 parts by mass of a crosslinking assistant, per 100 parts by mass of the total amount of the resin.

The conditions for extrusion-molding the resin composition of the present invention are not particularly limited as long as the resin composition of the present invention can be extruded, and the extrusion temperature (head) is preferably 100to 230 ℃, more preferably 120 to 200 ℃ from the viewpoint of reducing the load on the extruder (extrusion molding machine) and ensuring the shape-retaining property.

In addition, as other conditions for extrusion molding, usual conditions can be appropriately set, and there is no particular limitation. The extrusion speed (extrusion line speed) is not limited, and particularly, in the present invention, it is excellent for high-speed extrusion and productivity is improved.

The screw configuration of the extruder is not particularly limited, and a general full flight screw, a double flight screw, a tip double flight screw, a Maddock screw, or the like can be used.

The shape and material of the conductor may be any shape and material (copper, aluminum, etc.) that are generally used in automotive harnesses.

In addition, the thickness of the coating layer is not particularly limited. When the resin composition of the present invention is used, there is an advantage that an insulated wire excellent in flexibility, hardness, crosslinking degree, flame retardancy, cold resistance and heat resistance can be obtained even if the thickness of the coating layer is reduced.