JPH07149959A - Resin composition for electrical insulation - Google Patents

Abstract

PURPOSE:To obtain the composition having high dielectric breakdown strength and high volume resistivity and being usable as an insulation material for various electrical appliances, transportation machines and wires and in plants, factories, etc. CONSTITUTION:The composition compriser an olefin polymer comprising structural units derived from a monomer (a) having an aromatic ring and structural units derived from a monomer (b) having a carboxyl group and/or a derivative thereof. The content of component (a) is 2X10<-6>-10<-4>mol per g of the resin composition, and that of component (b) is 2X10<-7>-10<-4>mol per g of the resin composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for electrical insulation, and more specifically, it has a high dielectric breakdown strength and a high volume resistivity, and exhibits extremely excellent electrical characteristics especially at high voltage. Therefore, the present invention relates to a resin composition for electrical insulation which can be preferably used as an insulating material for electric wire / cable coating materials, home electric appliances, transportation equipment, various plants, factories and the like.

[0002]

2. Description of the Related Art Heretofore, there has been proposed a technique for mixing a carboxylic acid compound or an aromatic compound with a polyolefin for the purpose of improving insulating properties. For example, graft resistance of impulse breakdown voltage is improved by grafting styrene onto polyolefin (Japanese Patent Publication No. 165506/1990), and improvement of impulse breakdown strength by blending polystyrene with polyethylene (Japanese Patent Laid-Open No. Sho 63-63). JP-A-301427), a blend of polyethylene with a polyolefin modified with maleic anhydride to prevent water trees and improve insulating properties (JP-A-62-62).
-100909), an aromatic carboxylic acid is blended with a polyolefin to improve dielectric breakdown (JP-A-60-23904), and an ethylene / styrene copolymer obtained by copolymerizing ethylene and styrene is used. Therefore, there are some that improve the electrical characteristics at high voltage.
However, all of them are equivalent or inferior in volume resistivity as compared with the case of using polyolefin alone.

[0003]

The dielectric strength is increased by simply introducing a monomer having an aromatic ring into the polyolefin, but the volume resistivity is not improved, and the introduction of a carboxyl group into the polyolefin results in a water resistance. Tree property is improved, but dielectric breakdown strength is not improved,
Further, there is a problem that the volume resistivity may be deteriorated depending on the introduced amount of the carboxyl group. The object of the present invention is to have both high dielectric breakdown strength and high volume resistivity, and since it exhibits extremely excellent electrical characteristics especially for high voltage, it is a covering material for electric wires and cables, household electrical appliances, transportation equipment, various plants, An object of the present invention is to provide a resin composition for electrical insulation that can be preferably used as an insulating material for factories and the like.

[0004]

DISCLOSURE OF THE INVENTION In view of the above, the inventors of the present invention have made extensive studies and found that a specific amount of a monomer unit containing an aromatic ring and a monomer unit containing a carboxyl group or a derivative thereof are contained. The present invention has been accomplished by finding that the above problems can be solved by using the composition of the olefin polymer as described above as an insulating material.

That is, the invention of claim 1 of the present invention is
An olefin polymer resin composition comprising (a) a monomer unit containing an aromatic ring and (b) a monomer unit containing a carboxyl group and / or a carboxyl group derivative, The content of the component is 2 × in 1 g of the resin composition.
10 ^-6 ~10 ^-4 mol, an electrically insulating resin composition, wherein the component (b) 2 content resin composition 1g in × 10 ^-7 ~10 ^-4 mol.

The invention of claim 2 of the present invention is the resin composition for electrical insulation according to claim 1, wherein the olefin polymer is a copolymer of the component (a), the component (b) and an olefin. .

The invention of claim 3 of the present invention is the resin composition for electrical insulation according to claim 1 or 2, wherein the component (b) is a carboxylic acid anhydride.

The present invention will be described in detail below. The olefin in the present invention refers to a hydrocarbon having an ethylenic double bond represented by the general formula C _n H _2n . Specifically, for example, ethylene, propylene, 1-butene, 2-
Butene, isobutylene, 1-pentene, 2-pentene,
2-methyl-1-butene, 3-methyl-1-butene, 2
-Methyl-2-butene, 1-hexene, 2,3-dimethyl-2-butene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene and the like can be mentioned. .

The olefin polymer in the present invention is a homopolymer or copolymer of these olefins. Specifically, high and medium pressure polyethylene, low pressure polyethylene,
Polypropylene, polybutene, polypentene, poly 4-
Methyl-1-pentene, ethylene-α-olefin copolymer, EPR, and the like, and those containing a small amount of diene, triene, and the like by copolymerization can be given. Among the above, low-density polyethylene by the high-pressure radical method is produced without using a metal-based catalyst or the like, and therefore it has few impurities and can be preferably used.

In the present invention, the monomer (abbreviated as (a) monomer) which is the monomer unit containing the aromatic ring of the component (a) is not particularly limited as long as it is a compound containing an aromatic ring. . The aromatic ring here is a definition of aromaticity (for example, translated by Toshio Goto “Basics of Organic Chemistry” 1
05-106, Tokyo Kagaku Dojin (1976) [Ri
chard S. Monson & John C. Shelton: Fundamentals of
Organic Chemistry. MacGraw-Hill. INC (1974)] refers to a ring structure having 4n + 2 (n is an integer) number of π-electrons, and includes, for example, pyridine and quinoline. Specific examples of the (a) monomer include ethylenically unsaturated 2
A compound having a heavy bond and containing an aromatic ring is preferable,
For example, styrene, methylstyrene, allyl benzoate, divinylbenzene, pinylnaphthalene and the like can be mentioned. Among them, styrene and divinylbenzene are preferable in the present invention because they are easily reacted and easily available.

The content of the component (a) is the resin composition 1 of the present invention.
2 × 10 ⁻⁶ to 10 ⁻⁴ mol in g, preferably 4 × 10 ⁻⁶
-8 × 10 ^-5 mol, more preferably 10 ^-5 -5 × 1
It is used in the range of 0 ^-5. Content is 2 × in 1 g of resin composition
If it is less than 10 ^-6 mol, the effect is not exerted, and if it exceeds 10 ^-4 mol, on the contrary, dielectric breakdown may occur at a lower electric field than when the component (a) is not contained.

In the present invention, the monomer (abbreviated as “(b) monomer”), which is the monomer unit containing the carboxyl group and / or the carboxyl group derivative of the component (b), is an ester, an acid anhydride or a metal salt thereof. And the like, and specific examples thereof include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, maleic anhydride, and itaconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, and methacrylic acid. Ethyl acid,
Propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, -n-butyl acrylate, -n-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, Methacrylic acid stearyl, maleic acid monomethyl ester, maleic acid monoethyl ester, maleic acid diethyl ester, fumaric acid monomethyl ester,
Examples thereof include unsaturated carboxylic acid esters such as glycidyl acrylate and glycidyl methacrylate. Among these, maleic anhydride is preferably used because it is particularly effective and inexpensive.

The content of component (b) is 2 × 10 ^{-7 to} 5 × 10 ^-5 mol, preferably 8 ×, in 1 g of the resin composition of the present invention.
10 ^{−7 to} 2 × 10 ⁻⁵ mol, particularly preferably 2 × 10 ⁻⁶
It is used in the range of -10 ^-5 mol. If the content of the component (b) of the present invention is less than 2 × 10 ^-7 mol per 1 g of the resin composition, sufficient effect is not exhibited, and if it exceeds 5 × 10 ^-5 mol, the volume resistivity may be lowered. is there.

The method for producing the resin composition of the olefin polymer containing the component (a) and the component (b) of the present invention is not particularly limited, and includes (1) (a) and / or (b). Method of introducing monomer as it is, (2)
(A) and / or (b) a method in which an olefin polymer is modified by using a monomer, and a modified olefin polymer is contained, and (3) the (a) and / or (b) monomer and an olefin are randomized. There are a method of using a copolymer copolymerized by copolymerization or block copolymerization, a method of combining these methods, and the like. Specifically, (a) (a) and (b) A method in which a modified olefin polymer obtained by blending a fixed amount with an olefin polymer and then modifying with a radical generator or the like is used alone or blended with the olefin polymer, (b) the modification A method of blending a copolymer obtained by copolymerizing (a) and / or (b) a monomer and an olefin with an olefin polymer;
(C) A method of blending a modified olefin polymer obtained by similarly modifying with (a) a monomer with (b) a copolymer obtained by copolymerizing a monomer and an olefin, (d) (b) Examples thereof include a method of blending a modified olefin-based polymer obtained by similarly modifying a monomer with a monomer (a) with a copolymer obtained by copolymerizing a monomer and an olefin. The resin composition for electrical insulation of the present invention can be crosslinked by a suitable method as described later, but it can also be modified with a monomer (a) and / or (b) at the time of crosslinking. The (a) and / or (b) monomers used in this case are not particularly limited, but those having a function as a crosslinking aid can be preferably used because the amount of the crosslinking agent is small.

Specific examples of the electrical insulating resin composition of the present invention include maleic anhydride-modified polyethylene and ethylene.
Blend composition of styrene copolymer, ethylene / styrene / maleic anhydride terpolymer, maleic anhydride modified ethylene / styrene copolymer, maleic anhydride modified ethylene / styrene / maleic anhydride terpolymer Examples thereof include a resin composition mainly composed of a polymer, a maleic anhydride-modified styrene-modified polyethylene, a styrene-modified ethylene / methyl acrylate copolymer, a styrene-modified ionomer and the like. In the present invention, a method of using an ethylene / styrene / maleic anhydride terpolymer is preferable because the polymerization is simple, the handling is easy, and the mechanical properties of the final product are preferable. A method using a modified ethylene / styrene copolymer can be particularly preferably used.

The average molecular weight of these polymers is about 1
000 to 500000, that is, those having a molecular weight of about WAX to those having an ultrahigh molecular weight can be used. In the present invention, the content of the component (a) is 2 × 10 ⁻⁶ to 10 ^{−4 in} 1 g of the resin composition for electrical insulation as described above.
mol, the content of component (b) is 2 × 10 ⁻⁷ to 10 ⁻⁴ mol
Is essential. Furthermore, for example, when the above-mentioned copolymer is used to blend with an olefin polymer to produce the resin composition for electrical insulation of the present invention, the component (a) and the component (b) in the copolymer are According to the content, the blending amount of the olefin-based polymer is determined so that the contents of the component (a) and the component (b) fall within the above range, but the copolymer is added to 100 parts by weight of the olefin-based polymer. From the viewpoint of physical properties, it is preferable to adjust the amount to 0.1 to 30 parts by weight.

Next, a method for producing a maleic anhydride-modified ethylene / styrene copolymer which is particularly preferable in the present invention is described below.
List the rows. First, ethylene and styrene are copolymerized by a high pressure radical polymerization method. At that time, the amount of styrene is 0.1 to 49.5 mol% of the total amount of the monomers to be introduced. Then, the obtained ethylene-styrene copolymer is used in the presence of a solvent or without using a solvent, benzoyl peroxide, lauryl peroxide, dicumyl peroxide, t-butyl hydroperoxide, α, α-bis (t -Butylperoxydiisopropyl) benzene, di-t-butylperoxide, 2,5-di (t-butylperoxy) hexine, azobisisobutyronitrile or other organic peroxide, or 2,3-dimethyl- 2,3-
Diphenylbutane, 2,3-diethyl-2,3-diphenylbutane, 2,3-diethyl-2,3-di (p-methylphenyl) butane, 2,3-diethyl-2,3-di (bromophenyl) A maleic anhydride-modified ethylene / styrene copolymer can be obtained by reacting maleic anhydride with a radical generator such as butane.

The olefin polymer used in the present invention preferably has no additives, but if necessary, it may be an inorganic filler, an organic filler, an antioxidant, a lubricant, an organic or inorganic pigment, an ultraviolet inhibitor, an optical agent. Stabilizers, dispersants, copper damage inhibitors, neutralizing agents, plasticizers, nucleating agents, pigments and the like may be added.

The electrically insulating resin composition of the present invention can also be crosslinked and used. The method for cross-linking is not particularly limited, for example, a cross-linking method using an organic peroxide such as impregnating an organic peroxide in a resin composition for electrical insulation and then heating to cross-link it, an electron beam , Β rays,
Any of a method of irradiating high-energy radiation such as γ-ray and a water-crosslinking method using a silane compound may be used. The gel fraction of the composition after crosslinking is preferably 50% or more. If it is 50% or less, heat resistance and the like become insufficient. The larger the gel fraction, the larger the effect of improving wear resistance, heat resistance and the like, which is preferable. As the cross-linking agent, a cross-linking agent by a free radical mechanism such as the above organic peroxide, a dicumyl compound, a cross-linking agent of natural or synthetic rubber such as sulfur or a sulfur compound, a silane compound, a dihydro compound or the like can be used. Further, a crosslinking aid can be used together during the crosslinking.

Next, an example of a molding method when the electric insulating resin composition of the present invention is used for coating an electric wire will be described. First,
Fixed tension for core wire consisting of single wire or aggregate wire,
Introduced at a speed into the wire coating die. The tension and speed can be arbitrarily selected according to the shape of the core wire, the diameter, the outer shape to be coated, the density of the coating material, the viscosity, and the like. Generally speaking, a fine electric wire is about 600 to 800 m / min, and a 50 mm cable is about 5 to 15 m / min. It is desirable to install a wire-changing device for the wire for the core wire between the wire feeder for the wire for the core wire and the wire coating die to prevent vibration of the wire for the core wire.

When the resin composition for electric insulation of the present invention is used for coating electric wires, the density of the composition is generally 0.91.
The melt index (hereinafter abbreviated as MI) is preferably 0.05 to 20 g / 10 min in the range of up to 0.94 g / cm ³ in consideration of extrusion processability into a cable. The wire coating die may be of any type such as an extrusion type or a spoiler type, and is preferably made of tungsten steel or chrome steel, which does not easily wear.

As an example of the coating with the resin composition, the core wire of the assembly wire is coated with the electromagnetic wave relaxation layer resin composition,
From there, a method of coating the electrically insulating resin composition of the present invention, a method of directly coating the wire with the electrically insulating resin composition of the present invention, and the like can be mentioned. The resin compositions may be laminated at the same time or sequentially. In these coating moldings, it is desirable to use the female die of the wire coating die in which the tip of the die is tapered as appropriate in combination.

Cooling after molding is optional such as natural cooling and cooling in a water tank, but it is desirable to cool relatively slowly in order to prevent internal defects. For example, 180 to 260
For cooling the coating material at about ℃, for example, 150 ℃, 11
It is desirable to provide three types of cooling tanks of about 0 ° C. and 80 ° C. for sequential cooling, or to gently cool by using a metal medium or the like. Then, a sheath material or a semiconductive layer may be further coated thereon.

Next, a molding method when the resin composition for electrical insulation of the present invention is used for a capacitor will be exemplified. The electrical insulating resin composition of the present invention is formed into a sheet by a usual method, or the electrical insulating resin composition of the present invention is vertically laminated on a metal-containing polyacetylene, and further a metal layer is laminated on the upper and lower sides thereof. A capacitor can be formed by vapor deposition.

The resin composition for electrical insulation of the present invention is suitable as an insulating material for coating electric wires, and is also optimal as an insulating material for capacitors and the like. For example, substitutes for insulators of high voltage power lines, insulation materials for high voltage parts such as X-ray generators,
Insulation material for various measuring instruments, insulation material for dry and wet battery containers, various printed circuit boards, household electrical or commercial electric sockets, various connectors, power distribution cords, electrical product parts, automotive power distribution equipment, and parts thereof It can also be used as an insulating material for mechanical products, gloves and jigs for working with high-voltage current.

[0026]

EXAMPLES Next, the present invention will be described more specifically by way of examples, but the present invention is not limited to the following examples without departing from the gist thereof. (Example 1) Polyethylene (1) in the amount shown in Table 1 of the following polymer (trade name: Lexron W200, manufactured by Nippon Petrochemical Co., Ltd.)
0, MFR = 1.0 g / min, density: 0.920 g /
After blending with cc), it was melt-kneaded at a resin temperature of 200 ° C. using an extruder of 50 mmφ and pelletized. 180 more
A 2 mm sheet sample was prepared by extrusion molding at 0 ° C., and the electrical characteristics were tested by the following test method. The test results are shown in Table 1.

(Examples 2 to 5) In the same manner as in Example 1, the following polymers were blended in polyethylene (1) in the amounts shown in Table 1 to prepare 2 mm sheet samples, and the electrical characteristics were tested.
The test results are shown together in Table 1.

Example 6 115 g of the resin composition of Example 1 was mixed with 5 g of dicumyl peroxide, kneaded with a roll at 120 ° C., and thermally crosslinked for 30 minutes by a press molding machine at 160 ° C. Create a 2mm sheet sample,
The electrical properties were tested. The gel fraction (the sample was crushed to within 35 to 20 mesh, extracted with xylene at 120 ° C. for 10 hours, and the residual ratio was determined by the following formula) was 90% by weight. The test results are shown together in Table 1.

Example 7 A sheet sample of 2 mm was prepared by adding 5 g of dicumyl peroxide to 101.5 g of the resin composition of Example 3 and thermally cross-linking in the same manner as in Example 6, The electrical properties were tested. The gel fraction was 91% by weight. The test results are shown together in Table 1.

Example 8 Polyethylene (1) was mixed with acrylic acid and dicumyl peroxide, and then 5
Melt kneading at a resin temperature of 200 ° C using an extruder of 0 mmφ
Pelletization was performed to prepare acrylic acid-modified polyethylene. In the same manner as in Example 1, the following polymer was blended in acrylic acid-modified polyethylene in the amounts shown in Table 1 to prepare a 2 mm sheet sample, and the electrical characteristics were tested. The test results are shown together in Table 1.

(Comparative Examples 1 to 4) In the same manner as in Example 1, the following polymers were added to polyethylene (1) in the amounts shown in Table 1 so that the content of the component (a) or the component (b) was the same as that of the present invention. A 2 mm sheet sample of a resin composition outside the range was prepared and tested for electrical properties. The test results are shown together in Table 1.

(Comparative Example 5) Polyethylene (1) plain 2
mm sheet samples were prepared as in Example 1 and tested for electrical properties. The test results are shown together in Table 1.

(Comparative Example 6) 100 g of polyethylene (1)
On the other hand, 5 g of dicumyl peroxide was blended and heat-crosslinked to form a 2 mm sheet sample in the same manner as in Example 6, and the electrical characteristics were tested. The gel fraction was 91% by weight. The test results are shown together in Table 1.

(Comparative Example 7) A 5 mm sheet sample of 5 mm was prepared by adding 5 g of dicumyl peroxide to 105.5 g of the resin composition of Comparative Example 3 and thermally cross-linking in the same manner as in Example 6, The electrical properties were tested. The gel fraction was 91% by weight. The test results are shown together in Table 1.

(Examples 9 to 10) In the same manner as in Example 1, the following polymers were added in the amounts shown in Table 1 for polyethylene (2) (trade name: Linirex AF3280 MF manufactured by Nippon Petrochemical Co., Ltd.).
R = 1.0 g / 10 min, density: 0.921 g / c
2 mm sheet sample was prepared by blending with c) and tested for electrical properties. The test results are shown in Table 2.

(Example 11) A sheet sample of 2 mm was prepared by blending 115 g of the resin composition of Example 9 with 5 g of dicumyl peroxide and thermally crosslinking in the same manner as in Example 6 to obtain the electrical characteristics. Was tested. The gel fraction was 90% by weight. The test results are shown together in Table 2.

(Comparative Example 8) Polyethylene (2) plain 2
mm sheet samples were prepared as in Example 1 and tested for electrical properties. The test results are shown together in Table 2.

(Comparative Example 9) 100 g of polyethylene (2)
On the other hand, 5 g of dicumyl peroxide was blended and heat-crosslinked to form a 2 mm sheet sample in the same manner as in Example 6, and the electrical characteristics were tested. The gel fraction was 91% by weight. The test results are shown together in Table 2.

Example 12 A 2 mm sheet sample was prepared in the same manner as in Example 1 using the following polypropylene-based copolymer modified with styrene and maleic anhydride, and the electrical characteristics were tested. The test results are shown together in Table 2.

(Example 13) Polypropylene (3) (manufactured by Nippon Petrochemical Co., Ltd.) in the amount shown in Table 1 was used for the following polypropylene copolymer modified with styrene and maleic anhydride.
Product name: Nisseki Polypro F120K, MFR = 1.5g /
min, density: 0.905 g / cc) and 2 mm
Sheet samples were prepared and tested for electrical properties. The test results are also shown in Table 2.

(Comparative Example 10) A polypropylene (3) plain 2 mm sheet sample was prepared in the same manner as in Example 1,
The electrical properties were tested. The test results are shown together in Table 2.

Example 14 In place of the polymer of Example 3, divinylbenzene [monomer (a) containing an aromatic ring] was used in an amount shown in Table 3, and polyethylene (1) was used.
After blending the polymer and divinylbenzene into
2m of 31.5g of dicumyl peroxide mixed with 101.5g of the resin composition and thermally crosslinked in the same manner as in Example 6
m sheet samples were prepared and tested for electrical properties. The gel fraction was 92% by weight. The test results are shown together in Table 3.

Example 15 Divinylbenzene was used in the amount shown in Table 3 in place of the polymer of Example 10, polyethylene (2) was blended with the polymer and divinylbenzene, and then 101.5 g of the resin composition was added. On the other hand, a sheet sample of 2 mm was prepared by blending 3 g of dicumyl peroxide and thermally crosslinked in the same manner as in Example 6 and tested for electrical characteristics. The gel fraction was 92% by weight. The test results are shown together in Table 3.

Example 16 The electrical characteristics were tested in the same manner as in Example 14 except that the amount of divinylbenzene was 0.4 parts by weight and the amount of dicumyl peroxide was 2 g. The gel fraction was 93% by weight. The test results are shown together in Table 3.

Example 17 The electric characteristics were tested in the same manner as in Example 15 except that the amount of divinylbenzene was 0.4 part by weight and the amount of dicumyl peroxide was 2 g. The gel fraction was 93% by weight. The test results are shown together in Table 3.

Comparative Example 11 A test was conducted in the same manner as in Example 14 except that the amount of divinylbenzene was 10 parts by weight and the amount of dicumyl peroxide was 5 g. Molding became impossible and a sample could not be prepared. The test results are shown together in Table 3.

(Test Method) Electrical Properties: Breakdown voltage and volume resistivity were measured. The measurement was performed under the following conditions. Applied voltage: 3300 V Effective electrode area: 19.6 cm ² Measuring machine: Vibration capacitance type insulation meter (Advantest TR84
11) Measured value: 10 minutes value after voltage application, average after 4 different points measurement environment: Under nitrogen atmosphere in oven

Polymer and Monomer Maleic Anhydride Modified Ethylene-Styrene Copolymer An ethylene-styrene copolymer produced by a high pressure radical polymerization method was reacted with maleic anhydride using dicumyl peroxide. Infrared spectroscopic analysis results Polymer 1
In g, styrene 0.03616g, (3.48 × 10 ^-4
mol), maleic anhydride 2.00 × 10 ⁻³ g (2.0
It was 4 × 10 ⁻⁵ mol). Ethylene-styrene-maleic anhydride random copolymer An ethylene monomer, a styrene monomer, and maleic anhydride were introduced into an autoclave, and polymerization was performed using a titanium-based catalyst. As a result of investigating by infrared spectroscopy, 0.121 g (1.16 × 10 ⁻³ mol) of styrene and 0.107 g (1.09 × 10 ⁻³ mol) of maleic anhydride were found in 1 g of the polymer. Ethylene-styrene random copolymer It was produced by a high pressure radical polymerization method. As a result of examination by infrared spectroscopy, 0.164 g (1.5
It was 8 × 10 ⁻³ mol). Ethylene-maleic anhydride random copolymer An ethylene monomer and maleic anhydride were introduced into an autoclave and polymerized using a titanium-based catalyst. As a result of investigating by infrared spectroscopy, 0.155 g (1.5
It was 8 × 10 ⁻³ mol). Polypropylene copolymer Polypropylene (trade name: Nippon Petrochemical Co., Ltd .: Nisseki Polypro E120G2, MFR = 1.2 g / min, density:
0.905 g / cc) was reacted with styrene and maleic anhydride with a radical generator. As a result of an infrared spectroscopic analysis, in 1 g of the polymer, 4.03 × 10 ⁻³ g of styrene (3.86 g of styrene)
× 10 ^-5 mol), maleic anhydride 1.90 × 10 ^-3 g
(1.94 × 10 ⁻⁵ mol). Divinylbenzene

[0049]

[Table 1]

[0050]

[Table 2]

[0051]

[Table 3]

From Table 1, Table 2 and Table 3, the resin composition for electric insulation of the present invention has high dielectric breakdown strength and high volume resistivity, but the content of the component (a) or the component (b) is high. It can be seen that the resin compositions of Comparative Examples, which are outside the scope of the present invention, are inferior in these electrical characteristics. In addition, from Table 3, the resin composition for electrical insulation of the present invention obtained by cross-linking divinylbenzene [monomer (a) containing an aromatic ring] which is a cross-linking aid together with dicumyl peroxide corresponds. It can be seen that the resin composition has the same or superior dielectric breakdown strength and volume resistivity as the resin composition for electrical insulation of the present invention which does not use a crosslinking aid of the resin composition.

[0053]

The electrical insulating resin composition of the present invention has both a high dielectric breakdown strength and a high volume resistivity, and is a thermoplastic resin, so that it can be used for various electric appliances, transportation equipment,
Since it can be widely used as an insulating material in electric wires, plants, factories, etc., it has a high industrial utility value.

Claims (3)

[Claims] 1. A resin composition of an olefin polymer comprising (a) a monomer unit containing an aromatic ring and (b) a monomer unit containing a carboxyl group and / or a carboxyl group derivative. The content of the component (a) is 2 × 10 ⁻⁶ to 10 ⁻⁴ mol per 1 g of the resin composition, and the content of the component (b) is 2 × 10 ⁻⁷ to 10 ⁻⁴ mol per 1 g of the resin composition. A resin composition for electrical insulation, comprising: 2. The olefin polymer is the component (a),
The resin composition for electrical insulation according to claim 1, which is a copolymer of the component (b) and an olefin. 3. The resin composition for electrical insulation according to claim 1, wherein the component (b) is a carboxylic acid anhydride.