JP2008179673A - Resin composition and sheathed electric wire, and manufacturing method of sheathed electric wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition capable of inexpensively enhancing heat ageing resistance properties and insulated electric wire using the same. <P>SOLUTION: The resin composition is obtained by kneading a silane modified batch, comprising a silane-grafted olefin resin, obtained by grafting an ethylenically unsaturated silane compound onto an olefin resin in the presence of a free radical initiator, or a silane-copolymerized olefin resin obtained by copolymerizing an olefin with an ethylenically unsaturated silane compound, with an antioxidant batch comprising a polymer having a solubility parameter of 17-18 (MJ/m<SP>3</SP>)<SP>1/2</SP>, an antioxidant and a silanol condensation catalyst. Preferably, the antioxidant batch/silane-modified batch mixing weight ratio is within the range of 40/60-5/95. Preferably, the antioxidant is contained in an amount of 10-30 pts.wt. relative to 100 pts.wt. of the polymer having a solubility parameter of 17-18 (MJ/m<SP>3</SP>)<SP>1/2</SP>. The resin composition is coated around the outer periphery of a conductor and crosslinked with water to give the sheathed electric wire. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resin composition, a covered electric wire, and a method for producing the covered electric wire. The present invention relates to a method for manufacturing a covered electric wire.

  Conventionally, covered electric wires have been used in a wide range of fields such as vehicles such as automobiles and electronic / electrical devices. A covered electric wire is manufactured by covering an outer periphery of a conductor with an insulating material such as olefin resin or polyvinyl chloride by extrusion or the like to form an insulating layer.

  When such a covered electric wire is used in a high-temperature atmosphere environment such as an automobile, heat aging characteristics and heat deformation characteristics are required, so that the insulation layer of the covered electric wire is subjected to a crosslinking treatment. There are many. Moreover, in order to improve the heat aging characteristics, an increasing amount of an anti-aging agent or the like is often added to the insulating layer of the covered electric wire.

 Known examples of the crosslinking treatment include an electron beam irradiation crosslinking method, a chemical crosslinking method, and a water crosslinking method. Among these, the electron beam irradiation crosslinking method and the chemical crosslinking method have a problem in that they require expensive and large special crosslinking equipment and the like, and the cost increases. Therefore, in recent years, there has been widely used a water crosslinking method that does not have such difficulties and can be easily crosslinked.

  For example, as described in Patent Document 1, a water crosslinking method using a silane compound as a crosslinking agent is known. In order to produce a coated electric wire by this water crosslinking method, a silane graft batch obtained by adding a silane compound to an insulating resin material and grafting it, and a catalyst batch for promoting water crosslinking of the insulating resin material ( A predetermined amount of pellets are blended with each other. And after forming the said blend into an outer periphery of a conductor as an insulating resin layer by extrusion molding etc., it exposes to high temperature, high humidity, or warm water, and a crosslinking reaction is produced.

JP 2004-235117 A

  When an anti-aging agent or the like is added to the insulating layer of the covered electric wire, the heat aging characteristics can be improved as the addition amount increases. However, in the water cross-linking method, when an anti-aging agent or the like is added to the catalyst batch, there is a problem that the anti-aging agent or the like is likely to precipitate (bloom) on the resin surface as the addition amount increases. In addition, when an anti-aging agent or the like is added to the silane graft batch, when the anti-aging agent or the like is mixed into the silane graft batch, the crosslinking reaction proceeds in part, and the heat aging characteristics are liable to deteriorate. there were.

  The problem to be solved by the present invention is to provide a resin composition and an insulated wire that can improve heat aging characteristics at low cost.

The resin composition according to the present invention comprises a silane-grafted olefin resin and / or an olefin and an ethylenically unsaturated silane compound obtained by grafting an ethylenically unsaturated silane compound to an olefin resin in the presence of a free radical generator. A silane-modified batch comprising a copolymerized silane-copolymerized olefin resin, an anti-aging batch containing a polymer having a solubility parameter of 17 to 18 (MJ / m ³ ) ^1/2 and an anti-aging agent, and silanol condensation The gist is that the catalyst is kneaded.

  The silanol condensation catalyst may be contained in the anti-aging agent batch.

  In this case, the weight ratio of the anti-aging agent batch to the silane-modified batch is preferably in the range of 40/60 to 5/95.

  At this time, polyethylene or polypropylene can be preferably used as the olefin resin, and ethylene or propylene can be used as the olefin.

  And as said polyethylene, the 1 type (s) or 2 or more types selected from a low density polyethylene, a medium density polyethylene, a high density polyethylene, and a linear low density polyethylene can be shown suitably.

The polymer having a solubility parameter of 17 to 18 (MJ / m ³ ) ^1/2 is selected from an ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate copolymer, and an ethylene-methyl acrylate copolymer. 1 type or 2 types or more to be shown can be shown suitably.

  In this case, the amount of vinyl acetate of the ethylene-vinyl acetate copolymer is in the range of 15 to 50% by weight, and the amount of ethyl acrylate of the ethylene-ethyl acrylate copolymer is 15 to 50% by weight. It is desirable that the amount of methyl acrylate in the ethylene-methyl acrylate copolymer is in the range of 15 to 50% by weight.

  And as said anti-aging agent, the 1 type (s) or 2 or more types selected from a phenolic antioxidant and sulfur type antioxidant can be shown suitably.

In this case, it is desirable to contain 5 to 50 parts by weight of the anti-aging agent with respect to 100 parts by weight of the polymer having the solubility parameter of 17 to 18 (MJ / m ³ ) ^1/2 .

Furthermore, 1 to 10 parts by weight of a copper damage inhibitor and / or 1 to 20 parts by weight of a zinc-based compound with respect to 100 parts by weight of a polymer having a solubility parameter of 17 to 18 (MJ / m ³ ) ^1/2. It is desirable to contain.

  On the other hand, the covered electric wire according to the present invention is characterized in that the resin composition is coated on the outer periphery of a conductor and is water-crosslinked.

  In this case, the gel fraction of the resin composition coated on the outer periphery of the conductor is desirably 50% by weight or more.

The method for producing a covered electric wire according to the present invention includes a silane-grafted olefin resin and / or an olefin and an ethylenically unsaturated product obtained by grafting an olefin resin with an ethylenically unsaturated silane compound in the presence of a free radical generator. A silane-modified batch made of a silane-copolymerized olefin resin obtained by copolymerizing a silane compound, an anti-aging agent batch containing a polymer having a solubility parameter of 17 to 18 (MJ / m ³ ) ^1/2 and an anti-aging agent And a silanol condensation catalyst blending step, a coating step of coating the blended resin composition on the outer periphery of the conductor, and a crosslinking step of water-crosslinking the coated resin in the presence of water or water vapor. This is the gist.

According to the resin composition of the present invention, since the anti-aging agent is added to the polymer having the solubility parameter of 17 to 18 (MJ / m ³ ) ^1/2 , the anti-aging agent is deposited on the resin surface (bloom). It becomes difficult to do. In addition, the anti-aging agent batch to which the anti-aging agent is added does not contain a silane-grafted olefin resin or a silane copolymerized olefin resin. Therefore, when the anti-aging agent is dispersed in the anti-aging agent batch, There is no possibility that the partial cross-linking reaction proceeds and the heat aging characteristics are deteriorated. Therefore, the heat aging characteristics can be improved at a low cost by water crosslinking by increasing the amount of the anti-aging agent added.

  In this case, when the weight ratio of the anti-aging agent batch to the silane-modified batch is in the range of 40/60 to 5/95, the degree of cross-linking by water cross-linking is high and the heat aging characteristics are further improved.

The polymer having a solubility parameter of 17 to 18 (MJ / m ³ ) ^1/2 is selected from an ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate copolymer, and an ethylene-methyl acrylate copolymer. If one kind or two or more kinds are selected, the resin composition can be produced at low cost.

In this case, the amount of vinyl acetate of the ethylene-vinyl acetate copolymer is in the range of 15 to 50% by weight, and the amount of ethyl acrylate of the ethylene-ethyl acrylate copolymer is 15 to 50% by weight. When the amount of methyl acrylate of the ethylene-methyl acrylate copolymer is in the range of 15 to 50% by weight, each copolymer has a solubility parameter of 17 to 18 (MJ / m ³ ) Since it tends to be within the range of ^1/2, the amount of the anti-aging agent added in the anti-aging agent batch can be increased.

  And when the said anti-aging agent is 1 type (s) or 2 or more types selected from a phenolic antioxidant and sulfur type antioxidant, it is further excellent in a heat-resistant aging characteristic.

In this case, when the solubility parameter is 17 to 18 (MJ / m ³ ) ^1/2 of 100 parts by weight of the polymer and 5 to 50 parts by weight of the anti-aging agent is contained, the heat aging characteristics are further improved. Excellent.

Furthermore, with respect to 100 parts by weight of the polymer having the solubility parameter of 17 to 18 (MJ / m ³ ) ^1/2 , 1 to 10 parts by weight of the copper damage inhibitor and / or 1 to 20 parts by weight of the zinc compound. When it is contained, the heat aging characteristics are further improved.

  On the other hand, the coated electric wire according to the present invention is inexpensive and excellent in heat aging characteristics because the resin composition is coated on the outer periphery of the conductor and water-crosslinked. Therefore, high reliability can be ensured over a long period of time.

  In this case, when the gel fraction of the resin coated on the outer periphery of the conductor is 50% by weight or more, the degree of crosslinking is high and the heat aging characteristics are further improved.

And according to the manufacturing method of the covered electric wire which concerns on this invention, since an anti-aging agent is added to the polymer whose solubility parameter is 17-18 (MJ / m < ³ >) ^<1/2 >, an anti-aging agent precipitates on the resin surface ( Bloom) In addition, the anti-aging agent batch to which the anti-aging agent is added does not contain a silane-grafted olefin resin or a silane copolymerized olefin resin. Therefore, when the anti-aging agent is dispersed in the anti-aging agent batch, There is no possibility that the partial cross-linking reaction proceeds and the heat aging characteristics are deteriorated. Therefore, since the addition amount of an anti-aging agent can be increased, it is possible to produce a coated electric wire that is inexpensive and excellent in heat aging characteristics by the water crosslinking method.

  Next, an embodiment of the present invention will be described in detail.

  The resin composition according to the present invention is obtained by kneading a crosslinkable silane-modified batch, an anti-aging agent batch, and a silanol condensation catalyst. The silanol condensation catalyst may be contained in the anti-aging agent batch, or may be added as a catalyst batch together with other polymers such as polyolefin.

  The mixing ratio of the silane-modified batch and the anti-aging agent batch is preferably in the range of 40/60 to 5/95 in terms of weight ratio. More preferably, it is in the range of 25/75 to 10/90. This is because when the amount of the silane-modified batch is less than 60% by weight, the degree of cross-linking tends to be low when the resin composition is coated on the outer periphery of the conductor and then water-cross-linked, and the heat aging characteristics are likely to deteriorate. On the other hand, when the anti-aging agent batch is less than 5% by weight, the amount of the anti-aging agent is reduced, so that the heat aging characteristics are liable to deteriorate. In addition, as will be described later, when the silanol condensation catalyst is contained in the anti-aging agent batch, the amount of the silanol condensation catalyst is reduced and the degree of crosslinking is likely to be lowered.

  The silane-modified batch is composed of a crosslinkable silane-grafted olefin resin or a crosslinkable silane copolymer olefin resin. The silane-modified batch may consist of either of these, or may consist of both. The term “crosslinkability” as used herein means that crosslinking is possible, and that silane crosslinking is performed by a water crosslinking method described later.

  A silane-grafted olefin-based resin is obtained by grafting an ethylenically unsaturated silane compound to an olefin-based resin in the presence of a free radical generator, and is obtained by heating above the decomposition temperature of the free radical generator. . The graft amount is preferably in the range of 0.1 to 5% by weight.

  Examples of the olefin resin include polyolefins such as polyethylene and polypropylene, and ethylene such as ethylene-α olefin copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, and ethylene-methacrylic acid ester copolymer. Exemplifying propylene-based copolymers such as propylene-based copolymers, propylene-α-olefin copolymers, propylene-vinyl acetate copolymers, propylene-acrylic acid ester copolymers, propylene-methacrylic acid ester copolymers Can do. These may be used alone or in combination. Preferred are polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, and ethylene-methacrylic acid ester copolymer.

  Examples of polyethylene include high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), and linear low density polyethylene (LLDPE). These may be used alone or in combination.

  As the ethylenically unsaturated silane compound, a so-called silane coupling agent that can crosslink between the molecules of the olefin resin can be used. For example, vinyl alkoxysilanes such as vinyltrimethoxysilane and vinyltriethoxysilane, vinylacetoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane and the like can be exemplified. These may be used alone or in combination of two or more.

  Free radical generators include benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, butyl peracetate, tert-butyl perbenzoate, 2,5-dimethyl-2,5-di An organic peroxide such as (tert-butylperoxy) hexane can be exemplified.

  The amount of the free radical generator is preferably in the range of 0.001 to 1 part by weight with respect to 100 parts by weight of the olefin resin. If the amount of the free radical generator to be present is too small, the amount of the ethylenically unsaturated silane compound grafted decreases, and if it is too large, an undesired cross-linking reaction easily proceeds, and the processability of the resin and the appearance of the coated resin deteriorate. It is easy to do.

  The silane-grafted olefin resin can be produced, for example, by melt-kneading an olefin resin, an ethylenically unsaturated silane compound, and a free radical generator with a twin screw extruder or the like.

  The silane copolymerized olefin resin is obtained by copolymerizing an olefin and an ethylenically unsaturated silane compound. Examples of olefins include ethylene, propylene, and butene. The copolymerization amount of the ethylenically unsaturated silane compound is preferably in the range of 0.1 to 15% by weight.

  The silane copolymerized olefin resin may contain a copolymerizable compound in addition to the olefin. Examples of the copolymerizable compound include vinyl acetate, acrylic acid ester, and methacrylic acid ester.

Since the silane-grafted olefin resin and silane copolymerized olefin resin forming the silane-modified batch have a crosslinkable silane moiety added to the olefin resin, the solubility parameter (SP) is usually 16 to 17 (M / Often m ³ ) ^½ .

The anti-aging agent batch contains at least a polymer having a solubility parameter of 17 to 18 (M / m ³ ) ^1/2 and an anti-aging agent. When the solubility parameter of the polymer is less than 17 (M / m ³ ) ^1/2 , the anti-aging agent in the anti-aging batch is likely to bloom, and it is difficult to obtain the desired heat aging characteristics. If m ³ ) exceeds ^1/2 , the compatibility with the silane-modified batch tends to be poor, the dispersion of the anti-aging agent becomes poor, and the desired heat aging characteristics are difficult to obtain.

Examples of the resin having a solubility parameter of 17 to 18 (M / m ³ ) ^1/2 include a copolymer of an olefin such as ethylene and propylene and a monomer such as vinyl acetate, acrylate ester, and methacrylate ester. be able to. One or more olefins may be used in combination. Moreover, you may use together 1 type, or 2 or more types of monomers copolymerized with olefins, such as vinyl acetate. When using 2 or more types together, it becomes a copolymer consisting of 3 or more types of monomers.

  Specifically, for example, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-methyl methacrylate copolymer And propylene-vinyl acetate copolymer, propylene-ethyl acrylate copolymer, propylene-methyl acrylate copolymer, propylene-ethyl methacrylate copolymer, propylene-methyl methacrylate copolymer, and the like. it can. These may be used alone or in combination of two or more.

The amount of the monomer copolymerized with the olefin is preferably in the range of 15 to 50% by weight. This is because the solubility parameter tends to be within a range of 17 to 18 (M / m ³ ) ^1/2 .

Examples of the antioxidant include a phenolic antioxidant and a sulfurous antioxidant. These may be used alone or in combination of two or more. The anti-aging agent batch to which the anti-aging agent is added contains the polymer having the solubility parameter of 17 to 18 (M / m ³ ) ^1/2 , so that the amount of the anti-aging agent may be increased more than before. it can. As the amount of the anti-aging agent increases, the heat aging characteristics can be improved. However, as the amount increases, the anti-aging agent tends to bloom in the anti-aging agent batch. Therefore, it is preferable to make it into the range of 5-50 weight part with respect to 100 weight part of polymers whose solubility parameter is 17-18 (M / m < ³ >) ^<1/2 >. More preferably, it exists in the range of 10-30 weight part.

  Examples of phenolic antioxidants include pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], thiodiethylenebis [3- (3,5-di-tert-butyl-). 4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N′-hexane-1,6-diylbis [3- (3,5- Di-tert-butyl-4-hydroxyphenylpropionamide), benzenepropanoic acid, 3,5-bis (1,1-dimethylethyl) -4-hydroxy, C7-C9 side chain alkyl ester, 2,4-dimethyl- 6- (1-methylpentadecyl) phenol, diethyl [[3,5-bis (1,1-dimethylethyl) 4-hydroxyphenyl] methyl] phosphonate, 3,3 ′, 3 ″, 5,5′5 ″ -hexa-tert-butyl-a, a ′, a ″-(mesitylene-2,4,6-triyl) tri -P-cresol, calcium diethylbis [[[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] phosphonate], 4,6-bis (octylthiomethyl) -o-cresol, Ethylenebis (oxyethylene) bis [3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate], hexamethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 1H, 3H, 5H) -trione, 1,3,5-tris [(4-tert-butyl-3-hydroxy-2,6-xylyl) methyl] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,6-tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamino) phenol, 2,6-di- tert-butyl-4-methylphenol, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 4,4'-butylidenebis (3-methyl-6-tert-butylphenol), 4,4'- Thiobis (3-methyl-6-tert-butylphenol), 3,9-bis [2- (3- (3-tert-butyl-4-hydroxy-5-methylphenyl) -propynoxy) -1,1- Dimethylethyl] -2,4,8,10-tetraoxaspiro (5,5) undecane and the like may be mentioned, and these may be used alone or in combination of two or more.

  Of these, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 3,3 ′, 3 ″, 5,5′5 ″ -hexa- is particularly preferable. tert-butyl-a, a ′, a ″-(mesitylene-2,4,6-triyl) tri-p-cresol, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxy Benzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione.

  Examples of sulfur-based antioxidants include imidazole compounds, thiazole compounds, sulfenamide compounds, thiuram compounds, dithiocarbamate compounds, xanthate compounds, and the like. You may use together. The imidazole compound referred to in the present invention contains a sulfur (S) atom.

  Examples of the imidazole compound include 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, 4-mercaptomethylbenzimidazole, 5-mercaptomethylbenzimidazole, and zinc salts thereof.

  Examples of the thiazole compounds include 2-mercaptobenzthiazole, di-2-benzthiazol disulfide, zinc salt of 2-mercaptobenzthiazole, cyclohexylamine salt of 2-mercaptobenzthiazole, 2- (N, N- And diethylthiocarbamoylthio) benzthiazole and 2- (4′-morpholinodithio) benzthiazole.

  Examples of the sulfenamide-based compound include N-cyclohexyl-2-benzthiazole sulfenamide, N-tert-butyl-2-benzthiazole sulfenamide, N-oxydiethylene-2-benzthiazole sulfenamide, N, N-diisopropyl-2-benzthiazole sulfenamide, N, N′-dicyclohexyl-2-benzthiazole sulfenamide and the like can be mentioned.

  Examples of the thiuram compounds include tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, dipentamethylenethiuram tetrasulfide, tetrakis (2-ethylhexyl) thiuram disulfide and the like.

  Examples of the dithiocarbamate compound include zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc di-n-butyldithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate, zinc N-pentamethylenedithiocarbamate, Examples thereof include zinc benzyldithiocarbamate.

  Examples of the xanthate-based compound include sodium isopropyl xanthate, zinc isopropyl xanthate, and zinc butyl xanthate.

  Of the above sulfur-based antioxidants, an imidazole compound is particularly preferable, and more specifically, 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, and a zinc salt of 2-mercaptobenzimidazole.

  As the silanol condensation catalyst, a catalyst capable of dehydrating condensation between silanols of the ethylenically unsaturated silane compound can be suitably used. For example, metal carboxylates such as tin, zinc, iron, lead and cobalt, titanate esters, organic bases, inorganic acids, organic acids and the like can be exemplified.

  Specifically, dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, stannous acetate, stannous caprylate, lead naphthenate, cobalt naphthenate, barium stearate, calcium stearate, tetrabutyl ester of titanate, Examples include titanic acid tetranonyl ester, dibutylamine, hexylamine, pyridine, sulfuric acid, hydrochloric acid, toluenesulfonic acid, acetic acid, stearic acid, maleic acid and the like.

  The amount of the silanol condensation catalyst is preferably in the range of 0.001 to 1 part by weight with respect to 100 parts by weight of the silane-grafted olefin resin, the silane copolymer olefin resin, or a mixed resin thereof. More preferably, it exists in the range of 0.01-0.5 weight part. This is because if the amount is less than 0.001 part by weight, the degree of cross-linking tends to decrease, and it is difficult to obtain desired heat aging characteristics. On the other hand, when the amount exceeds 1 part by weight, the appearance of the coated resin tends to deteriorate, and the tensile strength tends to decrease.

In the resin composition according to the present invention, the anti-aging agent batch may further contain a copper damage preventing agent. At this time, the amount of the copper damage inhibitor is preferably in the range of 1 to 10 parts by weight with respect to 100 parts by weight of the polymer having the solubility parameter of 17 to 18 (M / m ³ ) ^1/2 . Examples of copper damage inhibitors include oxalic acid derivatives, salicylic acid derivatives, hydrazine derivatives, and the like.

  In the resin composition according to the present invention, a flame retardant, a processing aid, a colorant, an inorganic filler, and the like may be appropriately added to the anti-aging agent batch as necessary.

  It does not specifically limit as a manufacturing method of the resin composition which concerns on this invention, A well-known manufacturing method can be used. For example, a silane-modified batch and an anti-aging agent batch are dry blended with an ordinary tumbler, or melted with an ordinary kneading machine such as a Banbury mixer, a pressure kneader, a kneading extruder, a twin screw extruder, or a roll. The composition can be obtained by kneading and uniformly dispersing.

The anti-aging batch is preferably prepared in advance before being kneaded with the silane-modified batch. Preparation of an anti-aging agent batch is carried out by, for example, blending a polymer having a solubility parameter of 17 to 18 (M / m ³ ) ^1/2 and an anti-aging agent with other additives as necessary, and a twin screw extruder. It can be carried out by melt kneading. At this time, a silanol condensation catalyst may be blended.

  Next, the covered electric wire and the manufacturing method thereof according to the present invention will be described.

  The coated electric wire according to the present invention is formed by coating the outer periphery of a conductor with the resin composition and water-crosslinking the coated resin. The conductor is not particularly limited, such as the diameter of the conductor or the material of the conductor, and can be appropriately determined according to the application. Also, the thickness of the insulating coating material is not particularly limited and can be appropriately determined in consideration of the conductor diameter and the like.

  The gel fraction of the coating resin of the coated electric wire according to the present invention is preferably 50% by weight or more. More preferably, it is 60% by weight or more. This is because the gel fraction is an index indicating the degree of cross-linking of the coating resin. If the gel fraction is low, the degree of cross-linking tends to be low, and the heat-resistant deformation characteristics are likely to deteriorate.

  In order to produce the coated electric wire according to the present invention, at least a blending step of blending the silane-modified batch and the anti-aging agent batch, and a coating step of coating the outer periphery of the conductor with the blended resin composition, It passes through the bridge | crosslinking process of water-crosslinking the resin coat | covered on the outer periphery of the conductor.

  In the blending step, the silane-modified batch and the antioxidant batch are blended. Blending can also be carried out by mixing the pellets together and continuously weighing and dropping them at a constant ratio on the hopper of the extruder during the coating process.

  In the coating step, extrusion coating or the like may be performed using a normal extrusion molding machine or the like. Then, after the covering step, the cross-linking step may be performed by exposing the covering resin of the electric wire whose outer periphery is covered with resin to water vapor or water. At this time, it is preferable to carry out within a range of 48 hours within a temperature range of room temperature to 90 ° C. More preferably, the temperature is in the range of 60 to 80 ° C. and in the range of 12 to 24 hours.

  The gel fraction (crosslinking degree) of the coating resin is adjusted by the grafting amount and copolymerization amount of the ethylenically unsaturated silane compound to the olefin resin, the type and amount of the silanol condensation catalyst, water crosslinking conditions (temperature and time), etc. can do.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

(Test material and manufacturer)
The test materials used in the present examples and comparative examples are shown together with the manufacturer, product name, and the like.

(A) Silane-modified batch / silane-grafted low density polyethylene (Si-g-LDPE) [Mitsubishi Chemical Corporation, trade name “XCF800N”, SP = 16.6]
Silane-grafted high-density polyethylene (Si-g-HDPE) [Mitsubishi Chemical Corporation, trade name “XHE740N”, SP = 16.6]

(B) Anti-aging agent batch ethylene-vinyl acetate copolymer (EVA) [Mitsui / DuPont Polychemical Co., Ltd., trade name “P1007”, vinyl acetate content 10%, SP = 16.8]
-Ethylene-vinyl acetate copolymer (EVA) [Mitsui DuPont Polychemical Co., Ltd., trade name "EV360", vinyl acetate content 25%, SP = 17.3]
-Ethylene-ethyl acrylate copolymer (EEA) [Mitsui DuPont Polychemical Co., Ltd., trade name "A709", ethyl acrylate content 34%, SP = 17.6]
・ Polystyrene (PS) [made by Nippon Polystyrene Co., Ltd., trade name “G899”, SP = 18.5]
・ Polyvinyl chloride (PVC) [manufactured by Shin-Daiichi PVC Co., Ltd., trade name “ZEST 1300Z”, SP = 19.6]
・ Phenol-based anti-aging agent [trade name “Irganox 1010” manufactured by Ciba Specialty Chemicals Co., Ltd.]
・ Sulfur-based anti-aging agent [trade name “Sinox 412S” manufactured by Sipro Kasei Co., Ltd.]
Copper damage prevention agent [Ciba Specialty Chemicals Co., Ltd., trade name “Irganox MD1024”]
Silanol condensation catalyst [trade name “Stan BL”, manufactured by Sankyo Co., Ltd.]
(C) Others • Product name “LZ033” manufactured by Mitsubishi Chemical Corporation (used as a catalyst batch of Comparative Example 1)

(Measuring method)
-Gel fraction The gel fraction was measured based on JASO D608. That is, about 0.1 g of the insulator sample is precisely weighed. This is put in a test tube, 20 ml of xylene is added, and it is heated in a constant temperature oil bath at 120 ° C. for 24 hours. Thereafter, the sample is taken out, dried in a dryer at 100 ° C. for 6 hours, and then allowed to cool to room temperature, and then the mass is precisely weighed. The mass percentage relative to the mass before the test was used as the gel fraction. 50% by weight or more is acceptable.

-Heat aging test The heat aging test was done based on JASO D608. That is, a heat aging test was performed at 160 ° C. for 520 hours and 180 ° C. for 144 hours corresponding to 120 ° C. for 10,000 hours. After that, when the self-diameter mandrel (bar) was wound 10 times and the insulator cracked, the heat aging characteristics were inferior, and “x” was assigned.

(Preparation of anti-aging agent batch)
The compounds shown in Table 1 were added to a biaxial extrusion kneader and kneaded, and then pellets were produced. The pellet was allowed to stand at room temperature for 30 days, and then the anti-aging agent and copper damage inhibitor that had been vibrated in a vibrator and bloomed on the surface were separated from the pellet, and the pellet on the sieve was made into an anti-aging agent batch by sieving.

(Preparation of covered electric wire)
The silane-modified batch and the anti-aging agent batch are added to a biaxial extrusion kneader and kneaded, and then 0.6 mm thick on a conductor (cross-sectional area of about 3 mm ² ) twisted by 37 0.32 mm diameter copper wires. Extrusion coated. Thereafter, a cross-linking treatment was performed with 100% water vapor at 80 ° C. for 24 hours to prepare a covered electric wire.

  About each obtained covered electric wire, the measurement of the gel fraction and the heat aging test were implemented. The results are shown in Table 1. In Table 1, the amount of each component of the (B) anti-aging agent batch is expressed in parts by weight. Moreover, the quantity of (A) silane modification | denaturation batch, (B) anti-aging agent batch, (C) others is represented by weight%. Note that the covered electric wires according to the examples and comparative examples both have a coating with a good degree of cross-linking with a gel fraction of 50% or more.

  As shown in Table 1, it can be seen that the covered electric wire according to the comparative example is inferior in heat aging characteristics because the insulator was cracked in the heat aging test. This is considered to be because in Comparative Example 1, the amount of the anti-aging agent is small. In Comparative Example 2, since the polymer having an SP value of less than 17 is used as the base polymer of the anti-aging agent batch, it is considered that the anti-aging agent and the copper damage preventing agent bloomed. In Comparative Examples 3 and 4, since the polymer having an SP value of more than 18 is used as the base polymer of the anti-aging agent batch, it is considered that the compatibility between the silane-modified batch and the anti-aging agent batch deteriorated.

  On the other hand, the insulated wire according to the example did not crack in the insulator in the heat aging test. As a result, it was confirmed that it was excellent in heat aging characteristics. This is presumably because the anti-aging agent and the copper damage preventing agent did not bloom because a polymer having an SP value in the range of 17 to 18 was used for the base polymer of the anti-aging agent batch.

  And since a covered electric wire can be manufactured using a resin composition that exhibits stable heat aging characteristics over a long period of time by water crosslinking, for example, an expensive and large-sized method such as an electron beam irradiation crosslinking method or a chemical crosslinking method. No special cross-linking equipment or the like is required, and it is possible to produce a coated electric wire that is inexpensive and has excellent heat aging characteristics.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

Claims (13)

Silane-grafted olefin resin obtained by grafting an ethylenically unsaturated silane compound to an olefin resin in the presence of a free radical generator and / or a silane copolymerized olefin obtained by copolymerizing an olefin and an ethylenically unsaturated silane compound A silane-modified batch made of a resin, an anti-aging batch containing a polymer having an solubility parameter of 17 to 18 (MJ / m ³ ) ^1/2 and an anti-aging agent, and a silanol condensation catalyst. A resin composition characterized.   The resin composition according to claim 1, wherein the silanol condensation catalyst is contained in the anti-aging agent batch.   The resin composition according to claim 1 or 2, wherein a weight ratio of the anti-aging agent batch to the silane-modified batch is in a range of 40/60 to 5/95.   4. The resin composition according to claim 1, wherein the olefin resin is polyethylene or polypropylene, and the olefin is ethylene or propylene.   The resin composition according to claim 4, wherein the polyethylene is one or more selected from low density polyethylene, medium density polyethylene, high density polyethylene, and linear low density polyethylene. The polymer having a solubility parameter of 17 to 18 (MJ / m ³ ) ^1/2 is selected from ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer 1 It is a seed | species or 2 or more types, The resin composition in any one of Claim 1 to 5 characterized by the above-mentioned.   The vinyl acetate content of the ethylene-vinyl acetate copolymer is in the range of 15 to 50% by weight, and the ethyl acrylate content of the ethylene-ethyl acrylate copolymer is in the range of 15 to 50% by weight. The resin composition according to claim 6, wherein the amount of methyl acrylate in the ethylene-methyl acrylate copolymer is in the range of 15 to 50% by weight.   The resin composition according to any one of claims 1 to 7, wherein the anti-aging agent is one or more selected from a phenol-based antioxidant and a sulfur-based antioxidant. 9. The anti-aging agent is contained in an amount of 5 to 50 parts by weight with respect to 100 parts by weight of the polymer having a solubility parameter of 17 to 18 (MJ / m ³ ) ^1/2 . The resin composition in any one. 1 to 10 parts by weight of a copper damage inhibitor and / or 1 to 20 parts by weight of a zinc-based compound per 100 parts by weight of a polymer having a solubility parameter of 17 to 18 (MJ / m ³ ) ^1/2 The resin composition according to claim 1, wherein the resin composition is a resin composition.   A coated electric wire, wherein the resin composition according to any one of claims 1 to 10 is coated on the outer periphery of a conductor and is water-crosslinked.   The covered electric wire according to claim 11, wherein the resin composition coated on the outer periphery of the conductor has a gel fraction of 50 wt% or more. Silane-grafted olefin resin obtained by grafting an ethylenically unsaturated silane compound to an olefin resin in the presence of a free radical generator and / or a silane copolymerized olefin obtained by copolymerizing an olefin and an ethylenically unsaturated silane compound Blending a silane-modified batch made of a resin, an anti-aging batch containing a polymer having an solubility parameter of 17 to 18 (MJ / m ³ ) ^1/2 and an anti-aging agent, and a silanol condensation catalyst;
A coating step of coating the outer periphery of the conductor with the blended resin composition;
A method for producing a coated electric wire, comprising: a crosslinking step of water-crosslinking the coated resin in the presence of water or water vapor.