JPH0873668A - Electrically insulating resin composition and electric wire / cable using the same - Google Patents

Abstract

(57) [Abstract] [Purpose] It has excellent electrical insulation performance such as volume resistance and dielectric breakdown strength, and is rich in cross-linking property, and there is no deterioration in the electrical insulation performance after cross-linking. We will develop electric wire / cables and DC cables that have a resin composition, and an insulating layer formed from the composition or crosslinked product. [Structure] A resin composition comprising (A) a polyolefin-based polymer as a main component and (B) a polymer or compound comprising a monomer having two or more carbon-carbon double bonds, wherein ethylene is included in the composition. An electrically insulating resin composition containing a specific amount of a bond and a specific functional group-containing monomer unit is used.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrically insulating resin composition and an electric wire / cable using the same. More specifically, the composition has excellent electrical insulation properties such as volume resistance and electric breakdown strength, or has excellent crosslinkability and has excellent electrical insulation properties that do not cause deterioration in electrical properties such as volume resistance and dielectric breakdown strength even when crosslinked. The present invention also relates to an electric insulating resin composition, an electric wire / cable having an insulating layer made of the composition or a crosslinked product thereof, or a direct current cable.

[0002]

2. Description of the Related Art Conventionally, as an insulating material for electric wires / cables, it is basically required that the volume resistance and the electric breakdown strength are high, and the permittivity and the dielectric loss tangent are small, and polyethylene is generally used. There is. Also, for large capacity power cables, etc., oil filled insulation (PO
However, although the POF has good insulation performance, it has a drawback that oil leaks and it is necessary to constantly replenish the oil. In recent years, cross-linked polyethylene or the like, which is obtained by cross-linking polyolefin such as polyethylene to increase heat resistance and strength, has been used. As these cross-linking methods, there are an electron beam cross-linking method, a chemical cross-linking method such as peroxide, and the like. However, the electron beam cross-linking method has a problem that the equipment is large-scale and the cost is high.
Further, although the chemical cross-linking method is economically inexpensive, the cross-linking agent remains, and the residue thereof causes problems such as reduction in volume resistance and generation of water tree.

On the other hand, as a method for improving electrical insulation, water tree, etc., a method in which a polyolefin modified with maleic anhydride is introduced into polyethylene (Japanese Patent Publication No. 5-15007).
Issue). Further, attempts have been made to improve the electrical insulation performance by introducing a double bond into the crosslinkable polyolefin in advance to reduce the amount of the crosslinking agent added (JP-A-4-11646). It does not fully satisfy both electrical insulation performance and heat resistance.

The present inventors have also previously found that by using maleic anhydride in a very small amount in a limited range, a very good insulating material is obtained. But,
Although such an insulating material shows a far superior insulating performance than ordinary crosslinked polyolefin by crosslinking,
Again, it cannot be said that the insulation performance such as volume resistance due to crosslinking is sufficiently satisfactory.

On the other hand, a technique has been proposed in which a carboxylic acid compound or an aromatic compound is mixed with a polyolefin for the purpose of improving insulating properties. For example, one having improved impulse breakdown voltage resistance by grafting polystyrene to polyolefin (Japanese Patent Publication No. 165506/1990), and one having blended polystyrene with polyethylene to improve impulse breakdown strength (Japanese Patent Laid-Open No. 63- (JP-A-62-10090) by blending polyethylene with a polyolefin modified with maleic anhydride.
No. 9), which improves the dielectric breakdown by blending a polyolefin with an aromatic carboxylic acid (JP-A-60-23).
No. 904) has been proposed. However, none of these have sufficiently improved both volume resistance and dielectric breakdown at a practical level. Also, the electrical insulation performance after crosslinking is not sufficiently satisfactory.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to volume resistance,
A resin composition having excellent electrical insulation performance such as dielectric breakdown strength, a composition having excellent cross-linking properties, and having excellent electrical insulation performance such as volume resistance and dielectric breakdown strength even after cross-linking, and an insulating layer formed from the composition or cross-linked product It provides an electric wire / cable and a DC cable.

[0007]

In such a situation,
As a result of intensive studies, the present inventors have completed the present invention. That is, the first invention of the present invention relates to a resin composition containing a polymer or compound comprising (A) a polyolefin-based polymer as a main component and (B) a monomer having two or more carbon-carbon double bonds. The composition 1 has 0.8 or more ethylene bonds per 1000 carbon atoms.
The electrically insulating resin composition is characterized in that at least one functional group-containing monomer unit of the following C1 to C4 contains 5 × 10 ⁻⁷ to 1 × 10 ⁻⁴ mol per g. [Functional group-containing monomer] C1: Carbonyl group or carbonyl group derivative-containing monomer C2: Hydroxyl group-containing monomer C3: Nitro group-containing monomer C4: Nitrile group-containing monomer

A second invention of the present invention is an electric wire comprising the electrically insulating resin composition according to claim 1 or a crosslinked product thereof as an insulating layer.
It is a cable.

The present invention will be described in detail below. The component (A) in the present invention means (A1) a non-polar polyolefin polymer, (A2) a functional group-containing olefin polymer, (A3) an aromatic ring-containing olefin polymer,
(A4) It includes an olefin polymer having a functional group and an aromatic ring.

The non-polar polyolefin polymer (A1) is a homopolymer or copolymer of a hydrocarbon having a double bond represented by the general formula C _n H _2n . Specific examples of the hydrocarbon include ethylene, propylene, 1-butene, and 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.

Specific examples of the nonpolar polyolefin polymer (A1) include nonpolar high / medium density polyethylene, linear low density polyethylene, ultra low density polyethylene,
Polypropylene, polybutene, polypentene, poly 4-
Methyl-1-pentene, ethylene-α-olefin copolymer, ethylene-propylene copolymer rubber (EPR),
Examples thereof include high-pressure radical method low-density polyethylene and copolymers thereof. Among the above polyolefin polymers, low-density polyethylene prepared by the high-pressure radical method is preferable because it does not use a metal catalyst and thus has few impurities and good electric characteristics.

The (A2) functional group-containing olefin polymer of the present invention is an olefin polymer having a polar group introduced therein, and specifically, C1: carbonyl group or carbonyl group derivative-containing monomer, C2: hydroxyl group. A polyolefin-based polymer containing at least one functional group-containing monomer unit of a containing monomer, a C3: nitro group-containing monomer, and a C4: nitrile group-containing monomer, and these are the above-mentioned polyolefin-based polymers (A1) of C1 to C4. A method of graft-modifying with at least one functional group-containing monomer,
Examples thereof include a method of randomly copolymerizing the above hydrocarbon with the functional group-containing monomer.

The functional group-containing monomer of the present invention means C1:
Carbonyl group or carbonyl group derivative-containing monomer,
At least one kind of functional group-containing monomer among C2: hydroxyl group-containing monomer, C3: nitrile group-containing monomer, and C4: nitro group-containing monomer, and specific examples are shown below.

Specific examples of the C1: carbonyl group- and carbonyl group derivative-containing monomer of the present invention include α, β-
Unsaturated carboxylic acids derived from unsaturated carboxylic acids,
Examples thereof include unsaturated carboxylic acid esters and vinyl esters derived from α, β-unsaturated carboxylic acid esters.

Specific examples of unsaturated carboxylic acids include:
Examples thereof include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid.

Specific examples of the unsaturated carboxylic acid ester include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate,
Isopropyl methacrylate, -n-butyl acrylate,
-N-Butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, maleic acid monomethyl ester, maleic acid monoethyl ester, maleic acid diethyl ester, fumaric acid monomethyl ester Examples thereof include esters, unsaturated carboxylic acid esters such as glycidyl acrylate and glycidyl methacrylate.

Specific examples of the vinyl ester include vinyl propionate, vinyl acetate, vinyl caproate, vinyl caprylate, vinyl laurate, vinyl stearate and vinyl trifluoroacetate.
Of these, vinyl acetate is preferred.

Examples of the acid anhydride group-containing monomer which is a carbonyl group derivative-containing monomer include maleic anhydride, itaconic anhydride, hymic acid anhydride, methyl maleic anhydride, dimethyl maleic anhydride, phenyl maleic anhydride and diphenyl maleic anhydride. , Chloromaleic anhydride, dichloromaleic anhydride, fluoromaleic anhydride, difluoromaleic anhydride, bromomaleic anhydride, dibromomaleic anhydride and the like.
Among these, maleic anhydride can be mentioned as a particularly preferable one.

Examples of the ketone group (carbonyl group) -containing monomer include carbon monoxide, methyl vinyl ketone, isopropenyl vinyl ketone, ethyl vinyl ketone, phenyl vinyl ketone, t-butyl vinyl ketone, isopropyl vinyl ketone, methyl propenyl ketone, and methyl. Examples thereof include isopropenyl ketone and cyclohexyl vinyl ketone.

Examples of the C2: hydroxyl group-containing monomer of the present invention include vinyl alcohol, 1-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and hydroxyethyl (meth) acrylate.

Examples of the C3: nitro group-containing monomer of the present invention include 2,4-dinitrophenyl acrylate, 2-nitrostyrene, m-nitrostyrene, o-nitrostyrene, p-nitrostyrene, p-nitrophenyl methacrylate and m. -Nitrophenyl methacrylate, 2,4-
Examples thereof include dinitrophenyl methacrylate and 2,4,6-trinitrophenyl methacrylate.

C4: Nitrile group-containing monomer (C4) of the present invention includes acrylonitrile, methacrylonitrile, α-methoxyacrylonitrile, vinylidene cyanide, cinnamonitrile, crotononitrile, α-phenylcrotononitrile, fumaronitrile, allylacetonitrile. , 2-butenenitrile, 3-butenenitrile and the like.

The amount of these functional group-containing monomers is 5 × 10 ⁻⁷ to 1 × 10 per 1 g of the resin composition containing no crosslinking agent.
^-4 mol, preferably 1 × 10 ^-7 to 1 × 10 ^-4 mol,
Particularly preferably, it is important to be in the range of 1 × 10 ^{−6 to} 5 × 10 ⁻⁵ mol. Especially C1 such as maleic anhydride
If the functional group of C4 is less than 5 × 10 ⁻⁷ mol, the effect of improving the volume resistance is not exhibited, and if it exceeds 5 × 10 ⁻⁴ mol, the volume resistance is deteriorated, which is not preferable.

In the present invention, specific examples of the olefin polymer (A2) containing at least one kind of functional group-containing monomer unit of C1 to C4 include ethylene, carbon monoxide copolymer and ethylene-methyl vinyl ketone copolymer. Polymer, ethylene-ethyl vinyl ketone copolymer, ethylene-methyl isopropenyl ketone copolymer, ethylene-hydroxyethyl (meth) acrylate copolymer, ethylene-2
-Nitrostyrene copolymer, ethylene-m-nitrostyrene copolymer, ethylene-p-nitrophenylmethacrylate copolymer, ethylene- (meth) acrylonitrile copolymer, ethylene-allylacetonitrile copolymer,
Examples thereof include maleic anhydride modified low density polyethylene, styrene modified low density polyethylene, acrylic acid or maleic anhydride modified high / medium density polyethylene, acrylic acid or maleic anhydride modified linear low density polyethylene and the like.

The olefin polymer containing an aromatic ring (A3) of the present invention is a graft copolymer of the above (A1) olefin polymer and a monomer having an aromatic ring, and the above hydrocarbon and aromatic ring. Examples thereof include random copolymers with the monomers that they have.

Examples of the aromatic ring-containing monomer include compounds containing a monocyclic or polycyclic aromatic ring and having an ethylenically unsaturated double bond. The aromatic ring-containing monomer is preferably an aromatic compound having 1 to 3 rings, specifically, styrene,
Allylbenzene, allylbiphenyl, methylstyrene,
Allyl benzoate, divinylbenzene, vinylnaphthalene, 4-phenyl-1-butene, benzyl methacrylate, allylstyrene, 1,1-diphenylethylene, 1
-Phenyl-1-tolylethylene, 1-phenyl-1-
Styrylethane, 1-tolyl-1-styrylethane,
2,4-diphenylbutene-1,2,4-diphenylpentene-1,2,4-diphenyl-4-methylpentene-1 and the like can be mentioned. Of these, a copolymer of ethylene and styrene is preferable in the present invention because it has good electrical performance and is economical.

The (A4) polyolefin-based polymer having a functional group and an aromatic ring of the present invention comprises at least one functional group-containing monomer unit of C1 to C4 and an aromatic ring-containing monomer unit. An olefin polymer containing, a random copolymer of at least one functional group-containing monomer of C1 to C4, an aromatic ring-containing monomer and olefin, a olefin polymer of the above (A1), and a C1 To a C4 graft copolymer in which at least one functional group-containing monomer and the aromatic ring-containing monomer are grafted, and a graft copolymer in which the functional group-containing olefin polymer (A2) is grafted with the aromatic ring-containing monomer. The polymer, an olefin polymer containing an aromatic ring (A3) described above, is mixed with at least one functional group-containing monomer of C1 to C4. DOO graft copolymer, and the like.

Specifically, ethylene-styrene-maleic anhydride random copolymer, maleic anhydride-modified ethylene-styrene copolymer, ethylene-allylbenzene copolymer, maleic anhydride-modified ethylene-benzyl methacrylate, anhydrous Examples include maleic acid-modified ethylene-allyl styrene. Specific examples of the copolymer of at least one of monomers containing a styrene derivative and ethylene include ethylene / VA / styrene copolymer and ethylene / VA / α-.
Methylstyrene copolymer, ethylene / VA / α-methyl-p-methylstyrene copolymer, ethylene / VA / α-
Methyl-o-methylstyrene copolymer, ethylene / VA
/ Α-methyl-m-methylstyrene copolymer, ethylene / VA / α-methyl-p-ethylstyrene copolymer, ethylene / VA / p-methylstyrene copolymer, ethylene / VA / o-methylstyrene copolymer Polymer, ethylene / VA
/ M-methylstyrene copolymer, ethylene / VA / p-
Ethyl styrene copolymer, ethylene / VA / o-ethyl styrene copolymer, ethylene / VA / m-ethyl styrene copolymer, ethylene / VA / p-phenyl styrene copolymer, ethylene / VA / p-propyl styrene Copolymer, etc., ethylene / EA / styrene copolymer, ethylene /
EA / α-methylstyrene copolymer, ethylene / EA /
α-methyl-p-methylstyrene copolymer, ethylene /
EA / α-methyl-o-methylstyrene copolymer, ethylene / EA / α-methyl-m-methylstyrene copolymer, ethylene / EA / α-methyl-p-ethylstyrene copolymer, ethylene / EA / p-methyl styrene copolymer, ethylene / EA / o-methyl styrene copolymer, ethylene / EA / m-methyl styrene copolymer, ethylene / EA / p-ethyl styrene copolymer, ethylene / EA
/ O-ethylstyrene copolymer, ethylene / EA / m-
Examples thereof include an ethylstyrene copolymer, an ethylene / EA / p-phenylstyrene copolymer, an ethylene / EA / p-propylstyrene copolymer and the like. And as another example,
Ethylene / VA / EA / styrene copolymer, ethylene /
VA / EA / α-methylstyrene copolymer, ethylene /
VA / EA / α-methyl-p-methylstyrene copolymer, ethylene / VA / EA / α-methyl-o-methylstyrene copolymer, ethylene / VA / EA / α-methyl-
m-methylstyrene copolymer, ethylene / VA / EA /
α-methyl-p-ethylstyrene copolymer, ethylene /
VA / EA / p-methylstyrene copolymer, ethylene /
VA / EA / o-methylstyrene copolymer, ethylene /
VA / EA / m-methylstyrene copolymer ethylene / V
A / EA / p-ethylstyrene copolymer, ethylene / V
A / EA / o-ethylstyrene copolymer, ethylene / V
A / EA / m-ethylstyrene copolymer, ethylene / V
A / EA / p-phenylstyrene copolymer, ethylene /
A VA / EA / p-propylstyrene copolymer etc. can be mentioned.

Unsaturated carboxylic acid ester monomer and /
Alternatively, when copolymerizing ethylene with a vinyl ester monomer and at least one of styrene and a monomer containing a styrene derivative, another unsaturated monomer can be further copolymerized as necessary.

Examples of the other unsaturated monomers include olefins such as propylene, butene-1, hexene-1, decene-1, octene-1.

The high-pressure radical polymerization method is, for example, ethylene.
87 to 98.99% by weight, unsaturated carboxylic acid ester monomer and / or vinyl ester monomer 1 to 10% by weight, and at least one of styrene and styrene derivative-containing monomers 0.01 to 3% by weight In the presence of 0.0001 to 1% by weight of a radical polymerization initiator, based on the total weight of all the simple substances, the polymerization pressure is 500 to 4000 kg / cm ² , preferably 1000 to 3500 kg / cm ² , and the reaction temperature is 50. To 400 ° C., preferably 100 to 350 ° C., the monomers are simultaneously or stepwise contacted in a tank or tube reactor in the presence of a chain transfer agent and, if necessary, an auxiliary agent, It is a method of polymerizing.

In the present invention, an olefin polymer containing an aromatic ring as the component (A3) and an aromatic ring containing at least one functional group-containing monomer unit of C1 to C4 as the component (A4) are used. The olefin polymer containing at least one aromatic ring selected from the olefin polymers contained in the composition is 0.1 to 5% by weight, preferably 0.2 to 3% by weight. Good to be used.

The component (B) in the present invention is (B1) a polymer composed of a monomer containing two or more carbon-carbon double bonds, and (B2) a functional group-containing carbon-carbon double bond.
Examples of the polymer include a polymer containing one or more monomers and (B3) a compound containing two or more carbon-carbon double bonds.

The component (B1) polymer comprising a monomer containing two or more carbon-carbon double bonds means a polymer of a compound having two or three intramolecular ethylene double bonds, or It is a copolymer, and it is necessary that sufficient double bonds are present after polymerization. Due to the presence of the double bond, the crosslinking property can be sufficiently exhibited. The component (B) may be a liquid or oligomer having an average molecular weight of 1,000 to 200,000, a polymer or the like. The number of ethylene bonds (double bonds) present in the resin composition is 10 carbon atoms.
It is preferably 0.8 to 20 per 00 pieces.

The first of the above-mentioned component (B1) has 4 to 1 carbon atoms.
It is up to 0 diene polymers. The diene may be cyclic or linear as long as the double bond participates in the polymerization. Among these, butadiene oligomer or polybutadiene having an average molecular weight of about 1,000 to 20,000 is most preferable in terms of excellent electrical insulation performance and crosslinking efficiency after crosslinking. Specifically, the compound is 1,3-diene.
Butadiene, 1,3-pentadiene, 1,4-pentadiene, 2-methyl-1,3-butadiene, 1,3-hexadiene, 1,4-hexadiene, 1,5-hexadiene, 2,4-hexadiene, 2, 3-dimethyl-1,3
-Butadiene, 2-ethyl-1,3-butadiene, 1,
3-heptadiene, 1,4-heptadiene, 3- (2-
Examples include propenyl) -cyclopentene, 2- (cyclopentyl) -1,3-butadiene and the like. The double bond of the diene may be either cis type or trans type. It is also possible to use triene or tetraene polymerized from a diene. Among the above, a homopolymer of 1,3-butadiene is preferably used because it has excellent crosslinking properties.

The second component (B1) of the present invention is a copolymer of an olefin and a monomer containing two or more carbon-carbon double bonds, preferably an ethylene copolymer. Specific examples thereof include ethylene-allyl (meth) acrylate copolymer, ethylene-vinyl (meth) acrylate copolymer, ethylene-glycidyl methacrylate-
Allyl (meth) acrylate copolymer, ethylene-glycidyl (meth) acrylate-vinyl (meth) acrylate copolymer, ethylene-ethyl acrylate-allyl (meth) acrylate copolymer, ethylene-ethyl acrylate −
Vinyl (meth) acrylate copolymer, ethylene-methyl acrylate-allyl (meth) acrylate copolymer, ethylene-methyl acrylate-vinyl (meth) acrylate copolymer, ethylene-vinyl acetate- (meth) Allyl acrylate copolymer, ethylene-vinyl acetate- (meth) vinyl acrylate copolymer, ethylene-n-butyl acrylate-
Allyl (meth) acrylate copolymer, ethylene-n-butyl acrylate-vinyl (meth) acrylate copolymer, ethylene-glycidyl methacrylate-ethyl or methyl acrylate or n-butyl-allyl (meth) acrylate or vinyl Examples thereof include copolymers, ethylene-glycidyl methacrylate-vinyl acetate-allyl (meth) acrylate, vinyl copolymers, and the like, and particularly preferably ethylene-
Allyl methacrylate copolymer, ethylene-glycidyl methacrylate-allyl methacrylate copolymer, ethylene-
Ethyl acrylate-allyl methacrylate copolymer, ethylene-vinyl acetate-allyl methacrylate copolymer, ethylene-glycidyl methacrylate-ethyl acrylate-
Examples thereof include allyl methacrylate copolymers and the like. You may use these copolymers in mixture of 2 or more types.

Another polymer (B2) of the present invention, which is composed of a monomer having two or more carbon-carbon double bonds containing a functional group, specifically includes two or more carbon-carbon double bonds. A random copolymer of a contained monomer and at least one functional group-containing monomer of C1 to C4, (B1) is C1.
To C4 copolymers graft-modified with at least one functional group-containing monomer.

Specifically, acrylic acid or maleic anhydride modified polybutadiene, maleic anhydride-butadiene copolymer, maleic anhydride modified ethylene-allyl (meth) acrylate copolymer, maleic anhydride modified ethylene-
Examples thereof include (meth) vinyl acrylate copolymer.

The compound having two or more carbon-carbon double bonds, which is the other component (B3) of the present invention, is a compound having two or three ethylene double bonds in one molecule, Specific examples thereof include polyfunctional methacrylate monomers represented by trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, etc., and polyfunctional representatives by triallyl isocyanurate, diallyl phthalate, vinyl butyrate, etc. Vinyl monomers, N, N '
-M-phenylene bismaleimide, bismaleimides represented by N, N'-ethylene bismaleimide, dioximes such as P-quinonedioxime, divinylbenzene,
Divinyl compounds such as 1,5-hexadiene-3-yne, hexatriene, divinyl ether, divinyl sulfone, allyl phthalate, 2,6-diacrylphenol,
Examples include diallyl compounds such as diallyl carbinol.

In the present invention, the component (B1) is a polymer composed of a monomer containing two or more carbon-carbon double bonds, and the component (B2) is a carbon-carbon dimer containing C1 to C6 functional group-containing monomer units. At least one component (B) selected from a polymer composed of a monomer having two or more heavy bonds and a compound having two or more (B3) carbon-carbon double bonds is contained in the composition in an amount of 0. It is used in an amount of 1 to 10% by weight, preferably 0.2 to 5% by weight.

The composition of the present invention comprises the above-mentioned component (A),
Component (B) is composed of at least two components and has 0.8 or more ethylene bonds per 1000 carbon atoms in the composition, and 5 × at least one functional group-containing monomer unit of C1 to C4 below per 1 g of the composition. It is essential to contain 10 ⁻⁷ to 1 × 10 ⁻⁴ mol.

The preferred specific combination examples of the present invention are shown below. In the first example, the component (A) described in claim 3 is a nonpolar polyolefin polymer (A1) and the component (B) is a carbon-carbon double bond containing the C1 functional group-containing monomer unit. A polymer composed of a monomer having three or more (B
2), and specific examples thereof include low-density polyethylene (A1) produced by high-pressure radical polymerization and maleic anhydride-modified liquid polybutadiene (B2).

In a second example, the component (A) described in claim 4 is a non-polar polyolefin polymer (A1) and a polyolefin polymer (A2) and (B) containing the C1 functional group-containing monomer unit. ) Component is a polymer (B2) consisting of a monomer having two or more carbon-carbon double bonds containing the C1 functional group-containing monomer unit, and specifically, low-density polyethylene (A) produced by high-pressure radical polymerization.
1) and maleic anhydride modified low density polyethylene (A2)
And maleic anhydride modified liquid polybutadiene (B2)
Etc.

In a third example, the component (A) described in claim 5 is a non-polar polyolefin-based polymer (A1), a polyolefin-based polymer (A2) containing the C1 functional group-containing monomer unit, and carbon-. A compound (B3) having two or more carbon double bonds, specifically, low-density polyethylene (A1) by high-pressure radical polymerization, maleic anhydride-modified low-density polyethylene (A2), divinylbenzene (B3) and the like. Can be mentioned.

In a fourth example, the component (A) described in claim 6 is an olefin polymer (A3) containing an aromatic ring, and the component (B) is a carbon containing a C1 functional group-containing monomer unit. A polymer (B2) composed of a monomer having two or more carbon double bonds, and specific examples thereof include ethylene-styrene random copolymer (A3) and maleic anhydride-modified liquid polybutadiene (B2). To be

In a fifth example, the component (A) described in claim 7 is an olefin polymer having an aromatic ring containing an aromatic ring-containing olefin polymer (A3) and a C1 functional group-containing monomer unit. (A4) and (B) component is C
A polymer (B2) comprising a monomer having two or more carbon-carbon double bonds containing one functional group-containing monomer unit, and specifically, ethylene-styrene random copolymer (A3) and ethylene-. Examples thereof include styrene-maleic anhydride random copolymer (A4) and maleic anhydride-modified liquid polybutadiene (B2). As another example, an ethylene-styrene random copolymer (A3)
And maleic anhydride-modified ethylene-styrene copolymer (A4) and maleic anhydride-modified liquid polybutadiene (B2).

In the olefin composition containing a specific functional group and an ethylene bond of the present invention, the electrical insulation performance such as volume resistance is increased by adjusting the specific amount of the specific functional group and then, particularly, by crosslinking the specific functional group. The method of cross-linking is arbitrary, but since it can be cross-linked with heat after molding and can be uniformly cross-linked,
A method of crosslinking using a crosslinking agent is particularly preferable. The cross-linking method is not particularly limited, and a radical generator such as an organic peroxide, electron beam cross-linking, silane cross-linking and the like can be used.

As the radical generator, benzoyl peroxide, lauryl peroxide, dicumyl peroxide, t-butyl hydroperoxide, α, α-
Bis (t-butylperoxydiisopropyl) benzene, di-t-butylperoxide, 2,5-di- (t
-Butylperoxy) hexane, 2,5-di- (t-butylperoxy) hexyne, peroxides such as azobisisobutyronitrile, 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) butane, and the like. Among them, dicumyl peroxide, 2,5-di- (t-butylperoxy)
Hexane, 2,5-di- (t-butylperoxy) hexine and the like are preferably used. The above crosslinking agent is (A),
The component (B) is used in an amount of 0.01 to 5 parts by weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight. If the amount is larger than this amount, the mechanical characteristics and the insulating property are deteriorated. If the amount is smaller than this amount, the crosslinking is insufficient and the effect is not obtained, and the insulating property is deteriorated.

In the present invention, it is preferable that the polyolefin does not have any additives, but if necessary, an inorganic filler, an organic filler, an antioxidant, a lubricant, an organic or inorganic pigment, an ultraviolet inhibitor, a light stabilizer, A dispersant, a copper damage inhibitor, a neutralizing agent, a plasticizer, a nucleating agent, a pigment and the like may be added.

The electrically insulating resin composition of the present invention is used as an insulating material for capacitors, insulation of high voltage parts such as X-ray generators, various measuring equipment, insulation of dry and wet battery containers, various printed boards, various connectors, It can also be used as an insulating material for power distribution cords, gloves for high-current work, and jigs and tools.

The electric wire / cable according to the second aspect of the present invention is an electric wire / cable comprising the resin composition or an insulating layer obtained by crosslinking the composition. What are the above electric wires and cables?
It is an electric wire cable in which at least a conductor is coated with the insulating resin composition of the present invention to form an insulating layer, and if necessary, the conductor portion is formed into an assembly line, or a semiconductive layer is provided between the conductor and the insulating layer. Alternatively, a flame-retardant resin layer can be formed outside the insulating layer. For example, to form a semiconductive layer by coating a resin composition containing conductive carbon or metal powder on a wire made of copper assembly wire, to form an insulating layer by coating the resin composition of the present invention thereon, further A metal sheet on which a coating or semi-conductive layer is provided, the outermost portion of which is coated with a flame-retardant resin or a rat-repellent resin, a copper single wire coated with a resin composition containing carbon or metal powder, and coated with a semi-conductive layer. As a conductive layer, an insulating layer is formed by coating the resin composition of the present invention on the conductive layer, and a metal film layer is further provided on the conductive layer. Examples thereof include a cable coated with a rat-repellent resin, and the like. The resin composition of the present invention is particularly effective for high-voltage electricity and is preferably used as a DC cable.

[0052]

The present invention is an electrically insulating resin composition having a specific functional group-containing monomer unit and an ethylene bond and / or aromatic ring-containing monomer unit in a composition containing an olefin polymer as a main component. . The functional group acts as a trap site and prevents the transfer of charges. This brings about an improvement in volume resistance. The aromatic ring has the effect of taking in high-energy electrons, dissipating the energy of the electrons as heat, and releasing them as low-energy electrons (electron energy absorption effect). As a result, the energy of the electrons that trigger the dielectric breakdown is reduced, and the dielectric breakdown strength is improved. Further, the cross-linking prevents the electrical characteristics of the insulating material, that is, the decrease in volume resistance and the deterioration of the water tree, and further improves the dielectric breakdown strength. The double bond in the diene polymer acts as a crosslinking point and improves the crosslinking efficiency. Further, upon crosslinking, the decomposition residue of the crosslinking agent is incorporated into the main chain. The cross-linking residue floating in the bulk is ion-decomposed by heat and an electric field and becomes a charge, which lowers the volume resistance. By incorporating this crosslinking residue in the main chain, it is possible to prevent this and increase the volume resistance. By utilizing these three effects, not only the deterioration of electrical properties after crosslinking, which has been a problem, can be prevented, but also the volume resistance and dielectric breakdown strength can be dramatically improved as compared with before crosslinking.

[0053]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. 1. Materials used (A) Component (A1) Polyolefin A1-1: High pressure radical method low density polyethylene (LDP)
E) [Density = 0.919 g / cm ³ , MFR = 1.0 g / 1
0 minutes Product name: Nisseki Lexron W2000, manufactured by Nippon Petrochemical Co., Ltd.] A1-2: Linear low density polyethylene (ethylene butene-
1 Copolymer: Ziegler type catalyst) (LLDPE) [Density = 0.921 g / cm ³ , MFR = 1.0 g / 1
0 minutes trade name: Nippon Rinirekkusu AF3280, Nippon Petrochemicals Co., Ltd.] A1-3: polypropylene (homopolymer, PP) [Density ^{= 0.905g / cm 3, MFR =} 1.5g / 1
0 minutes Brand name: Nisseki Polypro F120K, manufactured by Nippon Petrochemical Co., Ltd.] (A2) Functional group-containing olefin polymer A2-1: Maleic anhydride modified high pressure radical method low density polyethylene (MAnLDPE) High pressure method low density polyethylene (A1-1: LDPE) 100
0.75 parts by weight of maleic anhydride (functional group: C1-2) and 0.05 parts by weight of 2,5-dimethyl-2,5-di- (tert-butyl peroxide) are premixed in a Henschel mixer. After that, it was granulated with a twin-screw extruder at 230 ° C. to obtain modified polyethylene. The amount of maleic anhydride added by infrared spectroscopy was 2.66 × 10 ⁻⁵ mol per 1 g of the polymer.
Met. A2-2: Maleic anhydride-modified linear low density polyethylene (MAnLLDPE) It was prepared in the same manner as A2-1. As a result of an infrared spectroscopic analysis, the content of maleic anhydride in 1 g of the polymer was 2.66 × 1.
It was 0 ^-5 mol. (A3) Aromatic ring-containing olefin polymer A3-1: ethylene-styrene random copolymer (Et-
St) It was produced by a high pressure radical polymerization method. Infrared spectroscopic analysis showed that the content of styrene was 1.54 × 10 ⁻⁴ m in 1 g of the polymer.
It was ol. A3-2: Styrene-modified high-pressure radical method low-density polyethylene (St-g-LDPE) High-pressure method low-density polyethylene (A1-1: LDPE) and styrene monomer were heated in an autoclave to obtain styrene-modified polyethylene. Infrared spectroscopic analysis revealed that the content of styrene was 1.54 × 10 ⁻⁴ mol per 1 g of the polymer. (A4) Olefin-based polymer containing a functional group and an aromatic ring A4: An ethylene-styrene random copolymer produced by a high-pressure radical polymerization method using dicumyl peroxide, and maleic anhydride (functional group C1-2) was added (MAnEt-St). The content of styrene by infrared spectroscopic analysis was 3.4 × 10 ⁻⁴ mo per 1 g of the polymer.
1, the addition amount of maleic anhydride is 2.04 × in 1 g of the polymer.
It was 10 ⁻⁴ mol.

Component (B) (B1) Polymer consisting of monomers containing two or more carbon-carbon double bonds B1-1: Liquid polybutadiene (LPB) [average molecular weight = 3000, specific gravity = 0.89 g / cm ³ ,
Product name: Nisseki Polybutadiene B-3000, manufactured by Nippon Petrochemical Co., Ltd.] B1-2: Liquid polyisoprene (2-methyl-1,3-butadiene polymer, LPI) [Average molecular weight = 29000, 740 poise / 38] ℃ Brand name: Kuraprene LIR-30, manufactured by Kuraray Co., Ltd.] B1-3: Butadiene resin (PBR) [Specific gravity = 0.89 g / cm ³ Trade name: JSR RB8
20 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.] (B2) Polymer composed of monomers containing two or more functional group-containing carbon-carbon double bonds B2-1: maleic anhydride-modified liquid polybutadiene (MA
nLPB) A liquid polybutadiene (B1-1) modified with maleic anhydride (functional group C1-2) was used. [Average molecular weight = 30
00, specific gravity = 0.89 g / cm ³ Trade name: Nisseki Polybutadiene M-2000, manufactured by Nippon Petrochemical Co., Ltd.] The addition amount of maleic anhydride based on infrared spectroscopic analysis is Polymer 1
It was 4.32 × 10 ⁻⁴ mol in g. B2-2: Acrylic acid-modified liquid polybutadiene (AAnL
PB) Liquid polybutadiene (B1-1) modified with acrylic acid (functional group C1-1) was used. [Average molecular weight = 2000 Specific gravity = 0.91 g / cm ³ Trade name: Nisseki Polybutadiene MAC-1000, manufactured by Nippon Petrochemical Co., Ltd.] The amount of acrylic acid added by infrared spectroscopy is 2.20 × in 1 g of the polymer. It was 10 ⁻⁴ mol. B2-3: Mixture of ethylene / vinyl alcohol copolymer and liquid polybutadiene (referred to as EVOH) Ethylene / vinyl alcohol copolymer (EVOH, functional group: C2) obtained by hydrolyzing ethylene / vinyl alcohol copolymer And the liquid polybutadiene (B1-1) were mixed. The content of alcohol residue by infrared spectroscopy was 1.13 × 10 ⁻³ mol per 1 g of the polymer. B2-4: Mixture of liquid polybutadiene modified with vinyl nitrile (VNLPB) The liquid polybutadiene (B1-1) was modified with vinyl nitrile (VN functional group: C4). The amount of vinyl nitrile added by infrared spectroscopy was 1.99 × 1 in 1 g of the polymer.
It was 0 ^-4 mol. B2-5: Maleic anhydride modified liquid polyisoprene (MA
nLPI) Liquid polyisoprene (B1-2) in an autoclave
Was modified with maleic anhydride (functional group: C1-2). The amount of maleic anhydride added by infrared spectroscopy was 2.87 × 10 ⁻⁴ mol per 1 g of the polymer. B2-6: Acrylic acid-modified butadiene resin (AAAnPB
R) The butadiene resin (B1-3) was modified with acrylic acid (functional group: C1-1) in a single-screw extruder. The amount of acrylic acid added by infrared spectroscopy was 3.25 × 10 ^{−4 in} 1 g of the polymer.
It was mol. B2-7: Maleic anhydride-modified butadiene resin (MAn
PBR) The butadiene resin (B1-3) was modified with maleic anhydride (functional group: C1-2) in a single-screw extruder. The amount of maleic anhydride added by infrared spectroscopy was 3.44 per 1 g of the polymer.
It was × 10 ^-4 mol. (B3) Compound containing two or more carbon-carbon double bonds B3: Divinylbenzene (DVB)

(Examples 1 to 32) 100 parts by weight of resin pellets prepared by blending the above-mentioned components (A) and (B) in the composition ratios shown in Tables 1 to 5 and a crosslinking agent (dicumylperoxide) 0.05 Part by weight is melt mixed with a twin-screw extruder,
Then, it was made into a sheet by press working and used for each test. Tables 1 to 5 show the results of measuring the volume resistance, impulse fracture strength, and water tree. Number of ethylene bonds in the table (pieces / 1
000C) was obtained by infrared spectroscopy and is the value before crosslinking.

Comparative Examples 1 to 8 Table 6 shows the results of measuring the volume resistance and the like after adjusting in the same manner as in Example 1.

[0057]

[Table 1]

[0058]

[Table 2]

[0059]

[Table 3]

[0060]

[Table 4]

[0061]

[Table 5]

[0062]

[Table 6]

FIG. 4 shows the relationship between the volume resistance and the functional group content obtained in Examples 1 to 6 and Comparative Examples 1, 5, and 6. In Examples 1 to 6, high-pressure radical method low-density polyethylene (A1-1) and maleic anhydride-modified liquid butadiene (B2-1) were prepared in the formulations shown in Table 1. Examples 1-6
The volume resistance of the composition of Comparative Example 1 is the same as that of Comparative Example 1 (A1-1: high pressure radical method low density polyethylene) and Comparative Example 5 (A1-1: high pressure radical method low density polyethylene) in both temperature ranges of room temperature and 90 ° C. A2-1: Composition consisting of maleic anhydride-modified high-pressure radical method low-density polyethylene) and Comparative Example 6 (A2-1: Maleic anhydride-modified high-pressure radical method low-density polyethylene). That is, the volume resistance was improved by the interaction between the functional group and the ethylene bond. FIG. 5 shows Examples 7 to 10 and 12 to
17 shows the relationship between the volume resistance and the functional group content obtained in Comparative Examples 1, 7, and 8. Examples 7 to 10 have the formulations shown in Table 2 and have a high-pressure radical method low-density polyethylene (A1-1), a maleic anhydride-modified high-pressure radical method low-density polyethylene (A2-1) and a maleic anhydride-modified liquid butadiene (B).
2-1) is adjusted. Examples 12 to 14 are prepared by mixing the ethylene-styrene random copolymer (A3-1) and the maleic anhydride-modified liquid butadiene (B2-1) as shown in Table 3. Examples 15-1
7 is styrene-modified high-pressure radical method low-density polyethylene (A3-2) and maleic anhydride-modified liquid butadiene (B
2-1) was blended and adjusted as shown in Table 3. The volume resistances of the compositions of these examples are in Comparative Example 1 (A1-
1: high pressure radical method low density polyethylene) and Comparative Example 7 (A3-1: ethylene-styrene random copolymer)
Much higher. Therefore, the aromatic ring alone does not have the effect of improving the volume resistance. The volume resistance of Comparative Example 8 (A3-1: a composition comprising an ethylene-styrene random copolymer and A4: a maleic anhydride-modified ethylene-styrene random copolymer) was considerably high, but the dielectric breakdown strengths of Examples 12 to 1
It is lower than 5, and the water tree resistance is poor. Therefore, even the functional group and the aromatic ring cannot satisfactorily improve the electric characteristics, and the presence of the ethylene bond is necessary for improving the electric characteristics.

(Test method) The resin prepared by blending the components (A) and (B) in the composition ratios shown in Tables 1 to 5 and the cross-linking agent are melt-mixed by a twin-screw extruder, and then pressed into a sheet. And subjected to each test. [Volume Resistance Test Method] Using the electrode system shown in FIG. 1, a DC voltage of 3300 V was applied to the sample at room temperature and a nitrogen atmosphere of 90 ° C. to perform measurement. A vibrating capacitance type ammeter (TR8411 manufactured by Advantest) was used as a measuring instrument. The sample thickness is 0.
3 mm, effective electrode area is 19.6 cm ² . The volume resistance was determined from the measured current value 10 minutes after applying the voltage.
The measurement was performed 4 times, and the average value was used as data. FIG.
In the measuring apparatus of the volume resistance test shown in, 11 is a main electrode (50φ), 12 is a guard electrode (inner diameter 75φ, outer diameter 80)
φ), 13 is a sample, and 14 is a high voltage electrode (80φ).

[Breakdown voltage test method] As the electrode system, a fixed electrode shown in FIG. 2, a so-called McKeon electrode was used. The electrode system substrate 24 is made of polymethylmethacrylate and has a hole having a diameter of 1/2 inch in the center thereof. The electrode 21 was a 1/2 inch stainless steel ball. Sample 22 is a 50 μm-thick sheet cut into about 8 to 10 mm square, and this is sandwiched between the electrodes. A degassed epoxy resin 23 was filled between the sample and the electrode and cured. Such a McKeon electrode was dipped in a container filled with silicon oil, and this was placed in a constant temperature bath for measurement. The voltage waveform used for destruction was a negative polarity, 1.2 / 50 μS impulse waveform. The waveform was observed with an oscilloscope, and what was destroyed at the wave front was adopted as data, and an average value of 20 points or more was taken. In the breakdown voltage test measuring device shown in FIG.
Is a stainless steel ball, 22 is a sample, 23 is an epoxy resin,
Reference numeral 24 indicates a substrate made of polymethylmethacrylate.

[Measurement of Water Tree] The measurement of the water tree is shown in FIG.
10kV, 10k at room temperature for 30 days
A voltage of Hz was applied. After completion of the application, the water tree was stained and observed under a microscope, and it was judged as unpleasant one: × Unnoticeable one: Δ No unpleasant one: ○. In the apparatus for measuring a water tree shown in FIG. 3, 31 is a water tree measurement sample, 32 is a conductive plate, 33 is water, 34 is a ground electrode, 35 is a container whose bottom is a sample, and 36 is an application. The electrodes are shown.

[Manufacture of Cable] When the cable shown in FIG. 6 was manufactured with the composition of Example 1, the performance as a cable was good. In the cross-sectional view of the cable, 41 is a conductive member made of an assembly line of conductive metal 42 is an inner semiconductive layer 43 is an insulating resin composition 44 is an outer semiconductive layer 45 is an aluminum foil 46 is a protective material (inorganic Polyolefin containing flame retardant).

[0068]

INDUSTRIAL APPLICABILITY According to the present invention, the composition containing an olefin polymer as a main component and an electrically insulating composition having a specific functional group monomer unit and an ethylene bond enables volume resistance and dielectric breakdown. Excellent electrical insulation performance such as strength,
Moreover, since it is rich in cross-linking property and there is no deterioration in electric insulation performance after cross-linking, it is suitably used for electric wires, cables and the like. In particular, it becomes possible to use it for a DC cable which has been conventionally considered difficult with a polyolefin polymer. Further, the composition and the electric wire / cable of the present invention can be widely used as an insulating material in various electric appliances, transportation equipment, electric wires, plants, factories and the like.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a volume resistance measuring device.

FIG. 2 is an explanatory diagram of a breakdown voltage measuring device.

FIG. 3 is an explanatory diagram of a water tree measuring device.

FIG. 4 is a graph showing the relationship between volume resistance and functional group content rate.

FIG. 5 is a graph showing the relationship between volume resistance and functional group content.

FIG. 6 is an explanatory view of a cross section of the cable of the present invention.

[Explanation of symbols]

 11 Main Electrode 12 Guard Electrode 13 Sample 14 High Voltage Electrode 21 Stainless Steel Ball 22 Sample 23 Epoxy Resin 24 Polymethyl Methacrylate Substrate 31 Water Tree Measurement Sample 32 Conductive Plate 33 Water 34 Grounding Electrode 35 Container 36 Applying Electrode 41 Conductive Member 42 inner semiconductor layer 43 insulating resin composition 44 outer semiconductor layer 45 aluminum foil 46 protective material

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08F 279/02 MQP C08K 5/00 KEG C08L 25/02 LDS LDV LDW 47/00 LKJ 51/04 LKX LKY 51/06 LLD LLE 101/00 LSZ H01B 3/44 D

Claims (9)

[Claims] 1. A resin composition comprising (A) a polyolefin-based polymer as a main component and (B) a polymer or compound comprising a monomer having two or more carbon-carbon double bonds, the composition comprising: Ethylene bond has 1000 carbon atoms
0.8 or more per piece and the following C1 per 1 g of the composition
At least one functional group-containing monomer unit of C4 is 5 ×
An electrically insulating resin composition comprising 10 ⁻⁷ to 1 × 10 ⁻⁴ mol. [Functional group-containing monomer] C1: Carbonyl group or carbonyl group derivative-containing monomer C2: Hydroxyl group-containing monomer C3: Nitro group-containing monomer C4: Nitrile group-containing monomer 2. The composition according to claim 1, wherein (A1) a non-polar polyolefin polymer, (A2) a functional group-containing olefin polymer, (A3) an aromatic ring-containing olefin polymer, (A4) ) A polymer comprising at least one component (A) of an olefin polymer containing a functional group and an aromatic ring, and (B1) a monomer containing two or more carbon-carbon double bonds, B2) a polymer composed of a monomer containing two or more functional group-containing carbon-carbon double bonds, and (B3) at least one component (B) component of a compound containing two or more carbon-carbon double bonds. An electrically insulative resin composition comprising: 3. The composition according to claim 1, wherein (A1) a non-polar polyolefin polymer, (B2) C1: two or more carbon-carbon double bonds containing a carbonyl group or a carbonyl group derivative-containing monomer unit. An electrically insulating resin composition, which is a composition comprising a polymer comprising a monomer having 4. The composition according to claim 1, wherein (A1) a non-polar polyolefin polymer, (A2) C1: an olefin polymer containing a carbonyl group or a carbonyl group derivative-containing monomer unit, (B2) C1: carbonyl. An electrically insulative resin composition comprising a polymer comprising a monomer having two or more carbon-carbon double bonds containing a group or a carbonyl group derivative-containing monomer unit. 5. The composition according to claim 1, wherein (A1) a non-polar polyolefin polymer, (A2) C1: an olefin polymer containing a carbonyl group- or carbonyl group derivative-containing monomer unit, (B3) carbon-carbon. An electrically insulating resin composition, which is a composition comprising a compound having two or more double bonds. 6. The composition according to claim 1, wherein (A3) an olefin polymer containing an aromatic ring, (B2) C1: a carbon-carbon double bond containing a carbonyl group or a carbonyl group derivative-containing monomer unit. An electrically insulating resin composition, which is a composition comprising a polymer composed of two or more monomers. 7. The composition according to claim 1, wherein (A3) an olefin polymer containing an aromatic ring, (A4) C1: an olefin containing an aromatic ring containing a carbonyl group- or carbonyl group derivative-containing monomer unit. -Based polymer, (B2) carbon containing the functional group-containing monomer unit of C1
Electrically insulating property, which is a composition comprising a polymer composed of a monomer having two or more carbon double bonds and / or a compound comprising (B3) a compound having two or more carbon-carbon double bonds. Resin composition. 8. An electric wire / cable having an insulating layer composed of the electrically insulating resin composition according to claim 1 or a crosslinked product obtained by crosslinking the composition. 9. A direct current cable having an insulating layer composed of the electrically insulating resin composition according to claim 1 or a crosslinked product obtained by crosslinking the composition.