JPH10182748A - Ethylene-aromatic vinyl compound copolymer for electric insulator, composition for electric insulator, electric wire-covering material comprising the same copolymer and electric wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject copolymer having a specific composition and crystallinity and reduced breakdown voltage drop caused by repeated impulses an useful for an electric wire, etc., by copolymerizing ethylene with an aromatic vinyl compound by using a metallocene catalyst. SOLUTION: This ethylene.aromatic vinyl compound copolymer contains 0.05-3mol% of a structural unit derived from an aromatic vinyl compound and has >=40% crystallinity and reduced breakdown voltage drop caused from repeated impulses with enlarged applying times of the repeated impulses till generating the insulation breakdown and useful for a covering materiel of an electric wire, etc. The copolymer is obtained by ethylene with an aromatic vinyl compound (e.g. styrene) in the presence of a metallocene catalyst comprising a bridge-type metallocene compound [e.g. isopropylidene bis(indenyl) zirconium dichloride].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ethylene / aromatic vinyl compound copolymer for an electrical insulator, a composition for an electrical insulator containing the copolymer, a covering material for electric wires containing the same, and the covering material. The present invention relates to an electric wire covered with:

[0002]

2. Description of the Related Art Conventionally, crosslinked products of polyethylene, particularly low-density polyethylene, have been used for electric insulators such as covering materials for electric wires. Further, a resin composition for electric insulation in which an aromatic vinyl compound copolymer is blended with polyolefin is also used. However, insulators made of these resins or resin compositions are not ideal as insulators because the dielectric breakdown voltage is reduced by repeated impulses.

Japanese Patent Application Laid-Open No. Sho 60-158504 discloses an electrically insulated cable in which a blend of a styrene / ethylene copolymer having a styrene content of 5% by weight or more and a polyethylene is used as an insulator. However, the styrene
Since the ethylene copolymer has a high styrene content and a large amount of amorphous portions, sufficient electrical insulation cannot be obtained.

Japanese Patent Application Laid-Open No. 7-70223 describes an ethylene-styrene copolymer in which structural units derived from styrene are separated by two or more methylene groups. However, the above publication does not describe that the electrical properties of the ethylene / styrene copolymer are improved.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems associated with the prior art by improving the reduction of the dielectric breakdown voltage due to repeated impulse and repeating the process until the dielectric breakdown occurs. An object of the present invention is to provide an ethylene / aromatic vinyl compound copolymer for an electric insulator in which the number of times of application of an impulse is extended. Another object of the present invention is a composition comprising the above-mentioned copolymer, wherein the reduction of the dielectric breakdown voltage due to the repeated impulse is improved, and the number of times of application of the repeated impulse until the dielectric breakdown occurs is extended. It is to provide a body composition. Another object of the present invention comprises the above copolymer or composition, wherein the reduction of the breakdown voltage due to repeated impulses is improved,
In addition, it is an object of the present invention to provide an electric wire covering material in which the number of times of repeated impulse application until the occurrence of dielectric breakdown is extended.
Still another object of the present invention is an electric wire coated with the above-mentioned electric wire covering material, in which the reduction of the dielectric breakdown voltage due to the repeated impulse is improved, and the number of times of application of the repeated impulse until the dielectric breakdown occurs is extended. To provide an electric wire that can be used stably for a long period of time.

[0006]

The inventor of the present invention has conducted intensive studies to obtain an excellent insulating material used for electric wires.
By using a specific ethylene / aromatic vinyl compound copolymer, it has been found that an insulator having an improved decrease in dielectric breakdown voltage due to repeated impulses can be obtained, and the present invention has been completed.

That is, the present invention relates to the following ethylene / aromatic vinyl compound copolymer for electrical insulator, a composition containing this copolymer, a covering material for electric wires containing them, and an electric wire coated with this covering material. . (1) A copolymer obtained by copolymerizing ethylene and an aromatic vinyl compound in the presence of a metallocene catalyst (A), wherein the content of the structural unit derived from the aromatic vinyl compound is 0.05 to 3 mol. % And a degree of crystallinity of 40% or more. (2) The ratio of structural units constituting a chain structure in which two or more structural units derived from an aromatic vinyl compound are continuous is 1% or less based on all structural units derived from the aromatic vinyl compound. The copolymer according to (1) above. (3) The copolymer according to the above (1) or (2), wherein the aromatic vinyl compound is styrene. (4) The polymer according to any one of the above (1) to (3), wherein the metallocene catalyst (A) contains a bridge type metallocene compound. (5) The polymer according to the above (4), wherein the metallocene compound is isopropylidenebis (indenyl) zirconium dichloride. (6) A composition comprising an ethylene / aromatic vinyl compound copolymer obtained by copolymerizing ethylene and an aromatic vinyl compound in the presence of a metallocene catalyst (A), and an ethylene-based polymer, The content of the structural unit derived from the aromatic vinyl compound in the total of the structural unit constituting the ethylene / aromatic vinyl compound copolymer and the structural unit constituting the ethylene-based polymer is 0.05 to 3 mol%, and A composition for an electrical insulator, which has a degree of conversion of 40% or more. (7) In the ethylene / aromatic vinyl compound copolymer, the ratio of the structural units constituting a chain structure in which two or more structural units derived from the aromatic vinyl compound are continuous is equal to the total structural units derived from the aromatic vinyl compound. The composition according to the above (4), which is 1% or less of the composition. (8) The composition according to the above (4) or (5), wherein the aromatic vinyl compound is styrene. (9) The composition according to any one of the above (6) to (8), wherein the metallocene catalyst (A) contains a bridge type metallocene compound. (10) The polymer according to the above (9), wherein the metallocene compound is isopropylidenebis (indenyl) zirconium dichloride. (11) A covering material for electric wires, comprising the copolymer according to any one of (1) to (5) or a crosslinked product thereof. (12) A covering material for electric wires, comprising the composition according to any one of (6) to (10) or a crosslinked product thereof. (13) An electric wire covered with the electric wire covering material according to the above (11) or (12).

[0008] The ethylene / aromatic vinyl compound copolymer for an electrical insulator of the present invention (hereinafter sometimes simply referred to as an ethylene / aromatic vinyl compound copolymer) is prepared by reacting ethylene with an ethylene / aromatic vinyl compound copolymer in the presence of a metallocene catalyst (A). A copolymer obtained by copolymerizing an aromatic vinyl compound, wherein the content of a structural unit derived from the aromatic vinyl compound (hereinafter, sometimes referred to as the aromatic vinyl compound content) is 0.05 to 3 mol.
%, Preferably 0.05 to 1.3 mol%, and a copolymer having a crystallinity of 40% or more, preferably 45% or more.
The aromatic vinyl compound content is NMR, and the crystallinity is DS.
C (differential scanning calorimeter).

Among such copolymers, two or more structural units derived from an aromatic vinyl compound form a continuous chain structure (hereinafter sometimes referred to as an aromatic vinyl compound / aromatic vinyl compound chain structure). The ratio of the structural unit (hereinafter, sometimes referred to as the aromatic vinyl compound / aromatic vinyl compound chain structure content) is 1% or less, preferably 0.1% or less, based on all structural units derived from the aromatic vinyl compound. Is preferred. The content of the aromatic vinyl compound / aromatic vinyl compound chain structure is ¹³ C NMR.
It is a value obtained from:

When the content of the aromatic vinyl compound and the degree of crystallinity are within the above ranges, the decrease in the breakdown voltage due to the repeated impulse is improved, and the number of application of the repeated impulse until the dielectric breakdown occurs is extended.
An aromatic vinyl compound copolymer is obtained. Among the copolymers having the aromatic vinyl compound content and the crystallinity within the above range, when the aromatic vinyl compound / aromatic vinyl compound chain structure content is within the above range, the decrease in the dielectric breakdown voltage due to the repeated impulse is reduced. In particular, an ethylene / aromatic vinyl compound copolymer is obtained which has been particularly improved and in which the number of repetitive impulses applied until dielectric breakdown occurs is greatly extended.

The ethylene / aromatic vinyl compound copolymer of the present invention has a ¹³ C NMR spectrum and a B value obtained from the following formula of 0.90 to 1.50, preferably 0.95 to 1.20. , More preferably 1.00
It is preferably 1.15.

B value = [P _SE ] / (2 · [P _E ] ·
[P _s ]) (wherein [P _E ] is the mole fraction of the structural unit derived from ethylene in the ethylene / aromatic vinyl compound copolymer, and [P _s ] is the ethylene / aromatic vinyl compound copolymer weight. The content mole fraction of the structural unit derived from the aromatic vinyl compound in the coalesced, [P _SE ], is the ratio of the number of the aromatic vinyl compound / ethylene chain to the total number of dyads in the ethylene / aromatic vinyl compound copolymer. It is a ratio.)

The B value obtained by the above equation is an index indicating the distribution of ethylene and the aromatic vinyl compound in the copolymer, and is expressed by JC Randall (Macromolecules, 15,3,3).
53 (1982)) and J. Ray (Macromolecules, 10, 773 (1977)).

The larger the B value is, the shorter the block chain of the ethylene or the aromatic vinyl compound is, indicating that the distribution of the ethylene and the aromatic vinyl compound is more uniform. The smaller the B value is less than 1.00, the more uneven distribution of the ethylene / aromatic vinyl compound copolymer is, and the longer the block chain is.

The ethylene / aromatic vinyl compound copolymer of the present invention has an intrinsic viscosity [η] measured in decalin at 135 ° C. of 0.1 to 10 dl / g, preferably 0.2 to 10 dl / g.
Those having 8 dl / g are preferred.

Examples of the aromatic vinyl compound include styrene; mono- or polyalkylstyrenes such as methylstyrene, dimethylstyrene, and ethylstyrene; methoxystyrene, ethoxystyrene, vinylbenzoic acid, methylvinylbenzoate, vinylbenzyl acetate, hydroxystyrene, and the like. Functional group-containing styrene derivatives such as chlorostyrene and divinylbenzene; 3-phenylpropylene, 4-
Phenylbutene and the like.

[0017] The ethylene / aromatic vinyl compound copolymer of the present invention comprises, in addition to ethylene and the aromatic vinyl compound,
Within a range that does not impair the object of the present invention, α having 3 to 20 carbon atoms
-Olefin, cycloolefin, polar group-containing monomer, non-conjugated polyene and the like may be copolymerized.

The α-olefin includes ethylene,
Examples include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene and the like. Examples of the cycloolefin include cyclobutene, cyclopentene, cyclohexene, cyclooctene and the like. Further, as the polar group-containing monomer, vinyl acetate, acrylic acid, ethyl acrylate,
Examples include methacrylic acid, ethyl methacrylate, maleic acid, and maleic anhydride. Further, as the non-conjugated polyene, dicyclopentadiene, 1,4-hexadiene,
Cyclooctadiene, methylene norbornene, ethylidene norbornene and the like can be mentioned.

The ethylene / aromatic vinyl compound copolymer of the present invention is produced by copolymerizing ethylene and an aromatic vinyl compound in the presence of the metallocene catalyst (A).

As the metallocene catalyst (A), a metallocene catalyst conventionally used as a single-site catalyst and a metallocene catalyst similar thereto can be used without limitation. Particularly, a metallocene compound of a transition metal (transition metal) is used. A catalyst comprising the compound (B) and the organic aluminum oxy compound (C) and / or the ionized ionic compound (D) is preferably used.

As the metallocene compound (B), IUP
Family number 1 according to the revised version of the AC Inorganic Chemistry Nomenclature (1989)
A metallocene compound of a transition metal selected from Group 4 of the periodic table (long-period type) of the elements represented by Nos. To 18, specifically, a metallocene compound represented by the following general formula (1). MLx (1) In the formula (1), M is a transition metal selected from Group 4 of the periodic table, specifically, zirconium, titanium or hafnium, and x is the valence of the transition metal.

L is a ligand coordinating to the transition metal, and at least one of these ligands L is a ligand having a cyclopentadienyl skeleton, and having this cyclopentadienyl skeleton. The ligand may have a substituent.

The ligand having a cyclopentadienyl skeleton includes, for example, cyclopentadienyl group, methylcyclopentadienyl group, ethylcyclopentadienyl group, n- or i-propylcyclopentadienyl group, n-,
i-, sec-, t-, butylcyclopentadienyl group, hexylcyclopentadienyl group, octylcyclopentadienyl group, dimethylcyclopentadienyl group, trimethylcyclopentadienyl group, tetramethylcyclopentadienyl Group, pentamethylcyclopentadienyl group, methylethylcyclopentadienyl group, methylpropylcyclopentadienyl group, methylbutylcyclopentadienyl group, methylhexylcyclopentadienyl group, methylbenzylcyclopentadienyl group, Alkyl or cycloalkyl-substituted cyclopentadienyl groups such as ethylbutylcyclopentadienyl group, ethylhexylcyclopentadienyl group, methylcyclohexylcyclopentadienyl group, and further indenyl group, 4,5,6,7-tetrahydroindenyl Group, fluore And a nyl group.

These groups may be substituted with a halogen atom, a trialkylsilyl group or the like. Among these, an alkyl-substituted cyclopentadienyl group is particularly preferred.

When the metallocene compound (B) represented by the formula (1) has two or more groups having a cyclopentadienyl skeleton as the ligand L, a group having two cyclopentadienyl skeletons among them The two are linked via an alkylene group such as ethylene and propylene, a substituted alkylene group such as isopropylidene and diphenylmethylene, a silylene group or a dimethylsilylene group, a diphenylsilylene group, and a substituted silylene group such as a methylphenylsilylene group. Is also good.

L other than the ligand having a cyclopentadienyl skeleton is a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group, an aryloxy group, a sulfonic acid-containing group (-SO
₃ R ¹ ), a halogen atom or a hydrogen atom (here, R ¹ is an alkyl group, an alkyl group substituted with a halogen atom, an aryl group, or an aryl group substituted with a halogen atom or an alkyl group). Can be

Examples of the hydrocarbon group having 1 to 12 carbon atoms include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group and the like. More specifically, a methyl group, an ethyl group, an n-propyl group and an isopropyl group Groups, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, octyl group, decyl group, alkyl group such as dodecyl group, cyclopentyl group, cycloalkyl group such as cyclohexyl group, Examples include an aryl group such as a phenyl group and a tolyl group, and an aralkyl group such as a benzyl group and a neophyl group.

Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group,
n-butoxy group, isobutoxy group, sec-butoxy group, t-butoxy group, pentoxy group, hexoxy group, octoxy group and the like. Examples of the aryloxy group include a phenoxy group.

Examples of the sulfonic acid-containing group (—SO ₃ R ¹ ) include a methanesulfonato group, a p-toluenesulfonato group, a trifluoromethanesulfonato group and a p-chlorobenzenesulfonato group. Examples of the halogen atom include fluorine, chlorine, bromine and iodine.

The metallocene compound (B) represented by the above formula (1) is more specifically represented by the following general formula (2) when the valence of the transition metal is 4, for example. R ² _k R ³ _l R ⁴ _m R ⁵ _n M (2)

In the formula (2), M is a transition metal similar to the transition metal of the formula (1), preferably zirconium or titanium, and R ² is a group (ligand) having a cyclopentadienyl skeleton. , R ³ , R ⁴ and R ⁵ are each independently the same as L except for a group having a cyclopentadienyl skeleton or a ligand having a cyclopentadienyl skeleton in the general formula (1). k is an integer of 1 or more, and k + 1
+ M + n = 4.

In the following, a ligand wherein M is zirconium and having a cyclopentadienyl skeleton is at least 2
Examples of the metallocene compound (B) are shown below. Bis (cyclopentadienyl) zirconium monochloride monohydride, bis (cyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) methylzirconium monochloride, bis (cyclopentadienyl) zirconium phenoxymonochloride, bis (methyl) (Cyclopentadienyl) zirconium dichloride, bis (ethylcyclopentadienyl) zirconium dichloride, bis (n-
(Propylcyclopentadienyl) zirconium dichloride, bis (isopropylcyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) zirconium bis (methanesulfonate), bis (cyclopentadienyl) zirconium bis (p-toluenesulfonate ),Screw
(1,3-dimethylcyclopentadienyl) zirconium dichloride, bis (1-methyl-3-ethylcyclopentadienyl) zirconium dichloride, bis (1-methyl-3-propylcyclopentadienyl) zirconium dichloride and the like can do.

In the present invention, a metallocene compound (B) in which the above 1,3-substituted cyclopentadienyl group is replaced by a 1,2-substituted cyclopentadienyl group can also be used. In the above formula (2), R ² , R ³ , R
^At least two of ⁴ and R ⁵ , that is, R ² and R ³ are groups having a cyclopentadienyl skeleton (ligand);
A bridge type metallocene compound (B) in which at least two groups are bonded via an alkylene group, a substituted alkylene group, a silylene group or a substituted silylene group, etc.
Can also be exemplified. At this time, R ⁴ and R ⁵ are independently the same as L except for the ligand having a cyclopentadienyl skeleton described in the formula (1).

Examples of the bridge type metallocene compound (B) include isopropylidenebis (indenyl) zirconium dichloride, ethylenebis (indenyl) dimethylzirconium, and ethylenebis (indenyl).
Zirconium dichloride, ethylenebis (indenyl) zirconiumbis (trifluoromethanesulfonate) and the like can be mentioned.

In the present invention, it is desirable to use a metallocene compound represented by the following general formula (3) as the bridge type metallocene compound (B).

Embedded image

In the formula (3), M ¹ represents a transition metal atom belonging to Groups 4, 5, and 6 of the periodic table, and specifically includes titanium, zirconium, hafnium and the like. R ⁶ and R ⁷ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing group, an oxygen-containing group, and a sulfur-containing group. , A nitrogen-containing group or a phosphorus-containing group, specifically, a halogen atom such as fluorine, chlorine, bromine and iodine; an alkyl group such as methyl, ethyl, propyl, butyl, hexyl and cyclohexyl, vinyl, propenyl and cyclohexenyl. A hydrocarbon group having 1 to 20 carbon atoms such as an alkenyl group such as benzyl, phenylethyl, phenylpropyl and the like; an arylalkyl group such as phenyl, tolyl, dimethylphenyl, naphthyl and methylnaphthyl; A halogenated hydrocarbon group substituted by a halogen atom;

Silyls of monohydrocarbon-substituted silyls such as methylsilyl and phenylsilyl, dihydrocarbon-substituted silyls such as dimethylsilyl and diphenylsilyl, trihydrocarbon-substituted silyls such as trimethylsilyl and triethylsilyl, and hydrocarbon-substituted silyls such as trimethylsilyl ether Silicon-containing groups such as ethers, silicon-substituted alkyl groups such as trimethylsilylmethyl, and silicon-substituted aryl groups such as trimethylsilylphenyl; alkoxy groups such as hydroxy, methoxy and ethoxy; alloxy groups such as phenoxy and methylphenoxy; phenylmethoxy and phenyl An oxygen-containing group such as an arylalkoxy group such as ethoxy; a sulfur-containing group such as a substituent in which the oxygen of the oxygen-containing group is substituted with sulfur; an amino group, methylamino, dimethylamino or the like; A phosphorus-containing group such as a phosphino group such as dimethyl phosphinothricin; alkylamino group, phenylamino, nitrogen-containing groups such as an arylamino group or an alkyl aryl amino group such as methylphenylamino.

Among them, R ⁶ is preferably a hydrocarbon group, particularly preferably a hydrocarbon group having 1 to 3 carbon atoms such as methyl, ethyl and propyl. Also R ⁷
Is preferably a hydrogen atom or a hydrocarbon group, particularly a hydrogen atom, or methyl, ethyl or propyl having 1 to 1 carbon atoms.
It is preferably a hydrocarbon group of No. 3.

R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a halogenated hydrocarbon group having 1 to 20 carbon atoms; Among these, a hydrogen atom, a hydrocarbon group or a halogenated hydrocarbon group is preferred. R ⁸ and R ⁹ , R ⁹
At least one pair of R ^10, R ¹⁰ and R ¹¹ together with the carbon atoms to which they are attached, may form a monocyclic aromatic ring.

When there are two or more hydrocarbon groups or halogenated hydrocarbon groups other than the group forming an aromatic ring, these groups may be bonded to each other to form a ring. When R ¹¹ is a substituent other than an aromatic group, it is preferably a hydrogen atom.

Specific examples of the halogen atom, the hydrocarbon group having 1 to 20 carbon atoms, and the halogenated hydrocarbon group having 1 to 20 carbon atoms are the same as those described above for R ⁶ and R ⁷ .

X ¹ and X ² each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, an oxygen-containing group or a sulfur-containing group. Show. A halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms,
Specific examples of the oxygen-containing group include R ⁶ and R ⁷
The same can be exemplified.

Examples of the sulfur-containing group include R ⁶ and R ⁷
And the same groups as above, and methylsulfonate, trifluoromethanesulfonate, phenylsulfonate, benzylsulfonate, p-toluenesulfonate, trimethylbenzenesulfonate, triisobutylbenzenesulfonate, p-chlorobenzenesulfonate Phonate,
Sulfonate groups such as pentafluorobenzenesulfonate, and sulfinate groups such as methylsulfinate, phenylsulfinate, benzenesulfinate, p-toluenesulfinate, trimethylbenzenesulfinate, and pentafluorobenzenesulfinate. Can be illustrated.

Y ¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms, a divalent halogenated hydrocarbon group having 1 to 20 carbon atoms, 2
Divalent silicon-containing group, divalent germanium-containing group, divalent tin-containing group, -O-, -CO-, -S-, -SO-,-
^{_{SO 2 -, - NR 12 -}} , - P (R 12) -, - P (O) (R 12)
—, —BR ¹² — or —AlR ¹² — (where R ¹² is a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms,
A halogenated hydrocarbon group having 1 to 20 carbon atoms).

Specific examples of Y ¹ include methylene,
Alkylene groups such as dimethylmethylene, 1,2-ethylene, dimethyl-1,2-ethylene, 1,3-trimethylene, 1,4-tetramethylene, 1,2-cyclohexylene, 1,4-cyclohexylene, diphenylmethylene Divalent hydrocarbon groups having 1 to 20 carbon atoms, such as arylalkylene groups such as diphenyl-1,2-ethylene, etc .;
A halogenated hydrocarbon group obtained by halogenating a divalent hydrocarbon group from 20 to 20; methylsilylene, dimethylsilylene, diethylsilylene, di (n-propyl) silylene, di (i-propyl) silylene, di (cyclohexyl) silylene, Methylphenylsilylene, diphenylsilylene, di (p-tolyl)
Alkylsilylenes such as silylene, di (p-chlorophenyl) silylene, alkylarylsilylene, arylsilylene group, tetramethyl-1,2-disilylene, alkyldisilylene such as tetraphenyl-1,2-disilylene, alkylaryldisilylene, 2 such as an aryldisilylene group
A divalent silicon-containing group; a divalent germanium-containing group obtained by substituting silicon in the divalent silicon-containing group with germanium; a divalent tin-containing group substituent obtained by substituting silicon in the divalent silicon-containing group with tin And R ¹² is a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a halogenated hydrocarbon group having 1 to 20 carbon atoms similar to those of R ⁶ and R ⁷ .

Among these, a divalent silicon-containing group, a divalent germanium-containing group, and a divalent tin-containing group are preferable, and a divalent silicon-containing group is more preferable. Preferred are silylene, alkylarylsilylene, and arylsilylene.

Specific examples of the metallocene compound (B) represented by the above formula (3) are shown below. rac-dimethylmethylenebis (indenyl) zirconium dichloride, rac-dimethylmethylenebis (2-methyl-1-indenyl) zirconium dichloride, rac-diphenylmethylenebis (2-methyl-1-indenyl) zirconium dichloride, rac-ethylenebis ( 2-methyl-1-indenyl) zirconium dichloride, rac-dimethylsilylenebis (2-methyl-1-indenyl) zirconium dichloride, rac-dimethylsilylenebis (2-methyl-1-indenyl) zirconium dimethyl, rac-dimethylsilylene- Bis (4,7-dimethyl-1-indenyl) zirconium dichloride, rac-dimethylsilylene-bis (2,4,7-trimethyl-1-indenyl) zirconium dichloride, rac-dimethylsilylene-bis (2,4,6- Trimethyl-1-indenyl) zirconium dichloride, rac-dimethylsilylene-bis (4-phenyl-1-indenyl) Zirconium dichloride, rac-dimethylsilylene-bis (2-methyl
4-phenyl-1-indenyl) zirconium dichloride,
rac-dimethylsilylene-bis (2-methyl-4- (α-naphthyl)
1-indenyl) zirconium dichloride, rac-dimethylsilylene-bis (2-methyl-4- (β-naphthyl) -1-indenyl) zirconium dichloride, rac-dimethylsilylene-bis (2-methyl-4- (1- Anthracenyl) -1-indenyl) zirconium dichloride and the like.

In the present invention, the metallocene compound (B)
As the metallocene compound represented by the following general formula (4). L ¹ M ² Z ₂ (4) (wherein, M ² is a metal belonging to Group 4 of the periodic table or a lanthanide series, L ¹ is a derivative of a delocalized π-bonded group,
The metal M ² active site has a constrained geometry,
Is independently a hydrogen atom, a halogen atom or 20
The following carbon, silicon or germanium containing hydrocarbon groups, silyl groups or germyl groups. )

Among the metallocene compounds (B) represented by the formula (4), a metallocene compound represented by the following general formula (5) is preferable.

Embedded image

In the formula (5), M ³ is titanium, zirconium or hafnium, and Z is the same as described above. Cp
Is a cyclopentadienyl group, a substituted cyclopentadienyl group or a derivative thereof, which is π-bonded to M ³ in an η ⁵ bonding mode.

W ¹ is oxygen, sulfur, boron or an element of group 14 of the periodic table, or a group containing these elements, and V ¹ is a ligand containing nitrogen, phosphorus, oxygen or sulfur. W ¹ and V ¹ may form a condensed ring. Also C
p and W ¹ may form a fused ring.

Preferred examples of the group represented by Cp in the general formula (5) include a cyclopentadienyl group, an indenyl group, a fluorenyl group, and a saturated derivative thereof. These groups include a metal atom (M ³ ) Form a ring. Each carbon atom in the cyclopentadienyl group is a halogen, a hydrocarbyl group, a substituted hydrocarbyl group (one or more hydrogen atoms of the group are replaced with halogen), and a hydrocarbyl-substituted metalloid group (the metalloid of the group Is selected from Group 14 of the Periodic Table of the Elements)
And may be substituted with the same or different groups selected from the group consisting of Also, one or more substituents may together form a bonded ring. Preferred hydrocarbyl and substituted hydrocarbyl groups which can be substituted for at least one hydrogen atom in the cyclopentadienyl group are 1 to
It includes linear or branched alkyl groups, cyclic hydrocarbon groups, alkyl-substituted cyclic hydrocarbon groups, aromatic groups and alkyl-substituted aromatic groups containing 20 carbon atoms.
Preferred organic metalloid groups are group 14 element mono-, -di-
And tri-substituted organic metalloid groups, each of the hydrocarbyl groups containing 1 to 20 carbon atoms. Specific examples of preferred organic metalloid groups include trimethylsilyl, triethylsilyl, ethyldimethylsilyl, methyldiethylsilyl, phenyldimethylsilyl,
Examples include methyldiphenylsilyl, triphenylsilyl, triphenylgermyl and trimethylshearyl.

Specific examples of Z ^{1 in} the general formula (5) include hydride, halo, alkyl, silyl, germyl, aryl, amide, aryloxy, alkoxy,
Examples include phosphide, sulfide, acyl, pseudo halide such as cyanide, azide, acetylacetonate or a mixture thereof, which may be the same or different.

Among the metallocene compounds (B) represented by the general formula (5), the metallocene compounds represented by the following general formula (6) are preferable.

Embedded image

In the formula (6), M ⁴ is the same as M ³ ,
V ² is -O -, - S -, - NR 17 -, - PR 17 - a either or ^{OR 17, SR 17, N (} R 17) 2 or P (R ^17), ₂
And a neutral two electron donor ligand selected from the group consisting of: Here, R ¹⁷ is a hydrogen atom, or an alkyl, aryl, silyl, halogenated alkyl or aryl halide group having up to 20 atoms other than hydrogen, or two R ¹⁷ or R ¹⁸ described below. A condensed ring may be formed.

In the equation (6), W^TwoIs Si (R¹⁸)_Two, C (R¹⁸)
_Two, Si (R¹⁸)_TwoSi (R¹⁸)_Two, C (R ¹⁸)_TwoC (R¹⁸)_Two, C
R¹⁸= CR¹⁸, C (R¹⁸)_TwoSi (R¹⁸)_Two, Ge (R¹⁸)_Two,
BR¹⁸, B (R¹⁸)_TwoIt is. Where R¹⁸Is R¹⁷Same as
The same. In the formula (6), R¹³~ R¹⁶Are each independently water
An elemental atom or an alkyl having up to 20 non-hydrogen atoms
Kill, aryl, silyl, jarmil, cyano, halo
And combinations thereof (eg alkaryl, aralkyl
, Silyl-substituted alkyl, silyl-substituted aryl, cyano
Alkyl, cyanoaryl, haloalkyl, halosilyl
Or R¹³~ R¹⁶Is an adjacent pair of cyclo
Forming a hydrocarbyl ring fused to a pentadienyl moiety
It may be.

In formula (6), Z ² is in each case a hydride or halo, alkyl, arylsilyl, germyl, aryloxy, alkoxy, amide, silyloxy and up to 20 atoms other than hydrogen. Their combinations (eg alkaryl, aralkyl,
Silyl, substituted alkyl, silyl-substituted aryl, aryloxyalkyl, aryloxyaryl, alkoxyalkyl, alkoxyaryl, amidoalkyl, amidoaryl, siloxyalkyl, siloxyaryl, amidosiloxyalkyl, haloalkyl, haloaryl, etc.) and up to 20 It is a group selected from the group consisting of neutral Lewis bases having atoms other than hydrogen.

In the metallocene compound (B) represented by the general formula (6), when V ² is a neutral two-electron donor ligand, the bond between M ⁴ and V ² is more precisely arranged. This is a bond called a covalent bond. Also, the complexes can exist as dimers or higher oligomers.

A metallocene compound represented by the general formula (6)
In (B), R¹³~ R¹⁶, Z ^Two, R¹⁷Or R¹⁸
Preferably, at least one of the is a donor moiety
Especially V^TwoIs -NR¹⁹-Or -PR¹⁹− (However,
R¹⁹Is alkyl having 1 to 10 carbons or 6 to 10 carbons
Or an phosphide corresponding to
It is preferably a group.

Among the metallocene compounds (B) represented by the general formula (6), an amidosilane or an amidoalkanediyl compound represented by the following general formula (7) is preferable.

Embedded image

In the formula (7), M ⁵ is titanium, zirconium or hafnium bonded to the cyclopentadienyl group in the η ⁵ bonding mode, and R ^{20 to} R ²⁵ are each independently a hydrogen atom or 10 hydrogen atoms. silyl with carbon up to, alkyl, aryl and a group selected from the group consisting of, or adjacent pairs of R ²² to R ²⁵ is to form a hydrocarbyl ring fused to the cyclopentadienyl moiety You may. In formula (7), W ³ is silicon or carbon and Z ³ is in each case hydride, halo,
It is an alkyl, aryl, aryloxy or alkoxy of up to 10 carbons.

In the metallocene compound (B) represented by the general formula (7), R ²⁰ is methyl, ethyl, propyl,
Butyl, pentyl, hexyl (including isomers), norbornyl, benzyl, phenyl, etc., wherein R ^{22 to} R ²⁵ are each independently a hydrogen atom, methyl, ethyl, propyl,
Butyl, pentyl, hexyl (including isomers), norbornyl, benzyl and the like, and Z ³ is chloro, bromo, iodo, methyl, ethyl, propyl, butyl, pentyl, hexyl (including isomers), norbornyl, benzyl And a metallocene compound such as phenyl. R ^{22 to} R ²⁵ form a condensed ring, and the cyclopentadienyl moiety is indenyl, tetrahydroindenyl,
Metallocene compounds such as fluorenyl and octahydrofluorenyl rings are also preferred.

Specific examples of the metallocene compound (B) represented by the general formula (7) include (t-butylamido) dimethyl (tetramethyl-η ⁵ -cyclopentadienyl) silanetitanium dichloride, (t-butylamido) butylamido) (tetramethyl-eta ⁵ - cyclopentadienyl) -1,2-ethanediyl zirconium dichloride, (t-butylamido) (tetramethyl-eta ⁵ - cyclopentadienyl) -1,2-ethanediyl titanium dichloride , (methylamide) (tetramethyl-eta ⁵ - cyclopentadienyl) -1,2-ethanediyl zirconium dichloride, (methylamide) (tetramethyl-eta ⁵ - cyclopentadienyl) -1,2-ethanediyl titanium dichloride , (ethylamide) (tetramethyl-eta ⁵ - cyclopentadienyl) - methylene titanium dichloride, (t-butylamido) Methyl (tetramethyl-eta ⁵ - cyclopentadienyl) silane zirconium dibenzyl, (benzylamide) dimethyl (tetramethyl-eta ⁵
- cyclopentadienyl) silane titanium dichloride, (phenyl phosphide) dimethyl (tetramethyl- eta ⁵ - and cyclopentadienyl) silane zirconium dibenzyl and the like.

In the present invention, the metallocene compound (B)
The following metallocene compounds can also be used.
Ethylene {2-methyl-4 (9-phenanthryl) -1-indenyl} (9-fluorenyl) zirconium dichloride, ethylene {2-methyl-4 (9-phenanthryl) -1-indenyl} (2,7-
Dimethyl-9-fluorenyl) zirconium dichloride, ethylene {2-methyl-4 (9-phenanthryl) -1-indenyl}
(2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, ethylene (2-methyl-4,5-benzo-1-indenyl) (9
-Fluorenyl) zirconium dichloride, ethylene (2-
Methyl-4,5-benzo-1-indenyl) (2,7-dimethyl-9-fluorenyl) zirconium dichloride, ethylene (2-methyl-4,5-benzo-1-indenyl) (2,7-di-t -Butyl-9-fluorenyl) zirconium dichloride, ethylene (2-methyl
-α-acenaphth-1-indenyl) (9-fluorenyl) zirconium dichloride, ethylene (2-methyl-α-acenaphth-
1-indenyl) (2,7-dimethyl-9-fluorenyl) zirconium dichloride, ethylene (2-methyl-α-acenaphth-1-
Indenyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, dimethylsilylene {2-methyl-4 (9-phenanthryl) -1-indenyl} (9-fluorenyl) zirconium dichloride and the like.

Other examples of the above zirconium compounds include compounds in which zirconium is replaced by titanium or hafnium. The method for producing the metallocene compound (B) is described in, for example, JP-A-3-163.
No. 088.

The metallocene compound (B) used in the present invention
As the metallocene compound, a metallocene compound represented by the general formula (4) is particularly preferable from the viewpoints of polymerization activity and electric insulating properties. The metallocene compounds (B) described so far may be used alone or in combination of two or more. The metallocene compound (B) used in the present invention may be used after being diluted with a hydrocarbon or a halogenated hydrocarbon.

Next, the organoaluminum oxy compound (C) and the ionized ionic compound (D) used for forming the metallocene catalyst (A) will be described.

The organoaluminum oxy compound (C) used in the present invention may be a conventionally known aluminoxane (C)
Or a benzene-insoluble organic aluminum oxy compound (C) as exemplified in JP-A-2-78687.

Such a known aluminoxane (C) is specifically represented by the following general formula (8) or (9).

Embedded image [In the formula (8) or (9), R ²⁶ is a hydrocarbon group such as a methyl group, an ethyl group, a propyl group, and a butyl group, preferably a methyl group, an ethyl group, particularly preferably a methyl group; Is an integer of 2 or more, preferably 5 to 40. ]

Here, this aluminoxane (C) is an alkyloxyaluminum unit represented by the formula (OAl (R ²⁷ )) and an alkyloxyaluminum unit represented by the formula (OAl (R ²⁸ )) (where R ²⁷ and R ²⁸ can be exemplified by the same hydrocarbon groups as R ^26, and R ²⁷ and R ²⁸ represent different groups).

The aluminoxane (C) is produced, for example, by the following method, and is usually recovered as a solution in a hydrocarbon solvent. (1) Compounds containing water of adsorption or salts containing water of crystallization such as hydrated magnesium chloride, hydrated copper sulfate, hydrated aluminum sulfate, hydrated nickel sulfate, hydrated cerous chloride A method of adding an organoaluminum compound such as trialkylaluminum to an aromatic hydrocarbon solvent in which is suspended and reacting the resulting mixture to recover a solution of the aromatic hydrocarbon solvent. (2) A method in which water (water, ice or steam) is allowed to directly act on an organic aluminum compound such as a trialkylaluminum in a medium such as benzene, toluene, ethyl ether or tetrahydrofuran to recover the compound as an aromatic hydrocarbon solvent solution. (3) A method of reacting an organoaluminum compound such as trialkylaluminum with an organotin oxide such as dimethyltin oxide or dibutyltin oxide in a hydrocarbon medium such as decane, benzene or toluene.

Solvents used in the preparation of aluminoxane (C) include, for example, aromatic hydrocarbons such as benzene, toluene, xylene, cumene and cymene; pentane, hexane, heptane, octane, decane, dodecane and hexadecane Hydrocarbons such as cyclopentane, cyclohexane, cyclooctane and methylcyclopentane; ethers such as ethyl ether and tetrahydrofuran; petroleum fractions such as gasoline, kerosene and light oil; Aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbon halides,
Examples thereof include hydrocarbon solvents such as chlorinated products and brominated products. Among these solvents, aromatic hydrocarbons are particularly preferred.

As the ionized ionic compound (D),
Lewis acids, ionic compounds, borane compounds, and carborane compounds can be exemplified. These ionized ionic compounds (D) are disclosed in JP-A No. 1-501950, JP-A No. 1-502036, and JP-A No. 3-17.
No. 9005, JP-A-3-179006, JP-A-3-207703, JP-A-3-207704, and USP-5321106.

As the Lewis acid used as the ionized ionic compound (D), BR ₃ (where R is the same or different and may have a substituent such as fluorine, methyl, trifluoromethyl, etc.) A phenyl group or fluorine), for example, trifluoroboron, triphenylboron, tris (4-fluorophenyl) boron, tris (3,5-difluorophenyl)
Boron, tris (4-fluoromethylphenyl) boron, tris (pentafluorophenyl) boron and the like.

The ionic compound used as the ionized ionic compound (D) is a salt comprising a cationic compound and an anionic compound. The anion functions to cationize the metallocene compound (B) by reacting with the metallocene compound (B), thereby stabilizing the transition metal cation species by forming an ion pair. Examples of such anions include an organic boron compound anion, an organic arsenic compound anion, and an organic aluminum compound anion, and those which are relatively bulky and stabilize transition metal cation species are preferable. Examples of the cation include a metal cation, an organic metal cation, a carbonium cation, a tripium cation, an oxonium cation, a sulfonium cation, a phosphonium cation, and an ammonium cation. More specifically, triphenylcarbenium cation, tributylammonium cation,
N, N-dimethylammonium cation, ferrocenium cation and the like.

Of these, ionic compounds containing a boron compound as an anion are preferred. Specific examples of the ionic compound include trialkyl-substituted ammonium salts, N, N-dialkylanilinium salts, dialkylammonium salts and trialkylammonium salts. Reel phosphonium salts and the like can be mentioned.

The above trialkyl-substituted ammonium salts include, for example, triethylammonium tetra (phenyl)
Boron, tripropylammonium tetra (phenyl) boron, tri (n-butyl) ammonium tetra (phenyl) boron, trimethylammonium tetra (p-tolyl) boron and the like.

Examples of the N, N-dialkylanilinium salt include N, N-dimethylanilinium tetra (phenyl)
Boron.

The dialkyl ammonium salts include:
For example, di (n-propyl) ammonium tetra (pentafluorophenyl) boron, dicyclohexylammonium tetra (phenyl) boron and the like can be mentioned.

The triarylphosphonium salts include, for example, triphenylphosphonium tetra (phenyl) boron, tri (methylphenyl) phosphonium tetra (phenyl) boron, tri (dimethylphenyl) phosphonium tetra (phenyl) ) Boron and the like.

Further, as the ionic compound, triphenylcarbenium tetrakis (pentafluorophenyl) borate, N, N-dimethylanilinium tetrakis
(Pentafluorophenyl) borate, ferrocenium tetra (pentafluorophenyl) borate and the like can also be mentioned.

Examples of the borane compound used as the ionized ionic compound (D) include the following compounds. Decaborane (14); salts of anions such as bis [tri (n-butyl) ammonium] nonaborate, bis [tri (n-butyl) ammonium] decaborate; and tri (n-
Metal borane anion salts such as (butyl) ammonium bis (dodecahydride dodecaborate) cobaltate (III) and bis (tri (n-butyl) ammonium) bis (dodecahydride dodecaborate) nickelate (III) Can be

Examples of the carborane compound used as the ionized ionic compound (D) include 4-carbanonaborane (1)
4) salts of anions such as 1,3-dicarbanonaborane (13); and tri (n-butyl) ammonium bis (nonahydride-1,3-dicarbanonaborate) cobaltate (II
I) and salts of metal carborane anions such as tri (n-butyl) ammonium bis (undecahydride-7,8-dicarboundecaborate) ferrate (III). The ionized ionic compound (D) as described above may be used in combination of two or more.

The metallocene catalyst (A) used in the present invention comprises:
If necessary, the composition may further contain the following organoaluminum compound (E) in addition to the above components. As the organoaluminum compound (E) optionally used in the present invention, for example, an organoaluminum compound represented by the following general formula (10) can be mentioned.

(R ²⁹ ) _n AlX _3-n (10) In the formula (10), R ²⁹ has 1 to 15 carbon atoms, preferably 1 to 15 carbon atoms.
4 is a hydrocarbon group, X is a halogen atom or a hydrogen atom, and n is 1 to 3.

Examples of such a hydrocarbon group having 1 to 15 carbon atoms include an alkyl group, a cycloalkyl group and an aryl group, and specifically, a methyl group, an ethyl group, an n-propyl group, Examples thereof include an isopropyl group and an isobutyl group.

Specific examples of such an organoaluminum compound include the following compounds. Trimethyl aluminum, triethyl aluminum, triisopropyl aluminum, tri n-butyl aluminum,
Triisobutylaluminum, in trialkylaluminum, formula _{(i-C 4 H 9)} xAly (C 5 H 10) z ( wherein such tri sec- butyl aluminum, x, y, z are each a positive number, z ≧ 2x) represented by alkenyl aluminum such as isoprenyl aluminum, dialkyl aluminum halide such as dimethyl aluminum chloride and diisobutyl aluminum chloride, dialkyl aluminum hydride such as diisobutyl aluminum hydride, dialkyl aluminum alkoxide such as dimethyl aluminum methoxide, and diethyl And dialkylaluminum aryloxides such as aluminum phenoxide.

As the organoaluminum compound (E), a compound represented by the following formula (11) can also be used. (R ³¹ ) _n Al (R ³⁰ ) _3-n (11) (wherein, R ³¹ is the same as R ²⁹ , and R ³⁰ is —OR ³²
Group, -OSi (R ³³⁾ ₃ group, -OAl (R ³⁴⁾ ₂ group, -N (R
³⁵⁾ ₂ group, -Si (R ³⁶⁾ ₃ group or ^{-N (R 37) Al (R} 38) 2
A group, n is ^{1~2, R 32, R 33,} R 34 and R ³⁸ and the like methyl, ethyl, isopropyl, isobutyl, cyclohexyl, phenyl, R ³⁵
Is hydrogen, methyl, ethyl, isopropyl, phenyl, trimethylsilyl, etc., and R ³⁶ and R ³⁷
Represents a methyl group, an ethyl group or the like. )

Such an organoaluminum compound (E)
Specific examples thereof include the following compounds. (C ₂ H ₅ ) ₂ Al (OSi (CH ₃ ) ₃ ), (iso-C ₄ H ₉ ) ₂ A
l (OSi (CH ₃ ) ₃ ), (C ₂ H ₅ ) ₂ Al (OAl (C
_{2 H 5) 2), (} CH 3) 2 Al (N (C 2 H 5) 2), (C 2 H 5) 2 Al
(NH (CH ₃ )), (iso-C ₄ H ₉ ) ₂ Al [N (Si (C
Such as H _{3) 3) 2].}

The metallocene catalyst (A) used in the present invention
May be a solid catalyst in which at least one of the components (B), (C), (D) and (E) described above is supported on a particulate carrier.

The metallocene catalyst (A) comprises a fine particle carrier, a component (B), a component (C) (or a component (D)), and a polymer or copolymer produced by prepolymerization, and if necessary, a component. And a prepolymerization catalyst comprising (E).

The particulate carrier used for the solid catalyst and the prepolymerization catalyst is an inorganic or organic compound having a particle size of 10 to 300 μm, preferably 20 to 200 μm.
It is a granular or particulate solid of μm.

Among them, a porous oxide is used as the inorganic carrier.
Preferably, specifically, SiO 2_Two, Al_TwoO_Three, MgO, Z
rO_Two, TiO_Two, B_TwoO_Three, CaO, ZnO, BaO, T
hO _TwoOr mixtures thereof, for example SiO 2_Two-M
gO, SiO_Two-Al_TwoO_Three, SiO_Two-TiO_Two, SiO_Two-
V_TwoO_Five, SiO_Two-Cr_TwoO_Three, SiO_Two-TiO_Two-MgO
And the like. Of these, SiO_TwoAnd
And Al_TwoO_ThreeAt least one member selected from the group consisting of
It is preferable that the main component is a component.

The above inorganic oxide contains a small amount of Na ₂ C
O ₃ , K ₂ CO ₃ , CaCO ₃ , MgCO ₃ , Na ₂ SO ₄ ,
Al ₂ (SO ₄ ) ₃ , BaSO ₄ , KNO ₃ , Mg (NO ₃ ) ₂ ,
It may contain carbonate, sulfate, nitrate and oxide components such as Al (NO ₃ ) ₃ , Na ₂ O, K ₂ O and Li ₂ O.

The properties of such a fine particle carrier differ depending on the kind and the production method, but the specific surface area is 50 to 1000.
m ² / g, preferably 100~700m ² / g, it is desirable that the pore volume is 0.3~2.5cm ³ / g. The finely divided carrier may be 100 to 1000 as needed.
C., preferably at a temperature of 150 to 700 C.

Further, as the fine particle carrier, a particle size of 10
Granular or fine-grained solids of organic compounds having a size of up to 300 μm can be mentioned. Such organic compounds include ethylene, propylene, 1-butene, 4-methyl-1
A (co) polymer formed mainly of an α-olefin having 2 to 14 carbon atoms such as pentene, or a polymer or copolymer formed mainly of vinylcyclohexane or styrene.

To produce the ethylene / aromatic vinyl compound copolymer of the present invention using the metallocene catalyst (A),
In the presence of the metallocene catalyst (A), ethylene and an aromatic vinyl compound are usually copolymerized in a liquid phase by solution polymerization or slurry polymerization.

Examples of such hydrocarbon solvents include aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane, dodecane and kerosene and halogen derivatives thereof; alicyclic hydrocarbons such as cyclohexane, methylcyclopentane and methylcyclohexane. Hydrogen and its halogen derivatives; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene and chlorobenzene, and their halogen derivatives are used. These solvents may be used in combination.

Ethylene and the aromatic vinyl compound may be copolymerized by either a batch method or a continuous method. When carrying out the copolymerization by a continuous method, the metallocene catalyst (A) is used in the following concentration.

That is, the concentration of the metallocene compound (B) in the polymerization system is usually 0.00005 to 0.1 mmol / liter (polymerization volume), preferably 0.0001 to 0.1.
05 mmol / liter. The organic aluminum oxy compound (C) is supplied in an amount of 0.1 to 10000, preferably 1 to 5000 in terms of the ratio of aluminum atoms to the metallocene compound (B) (Al / transition metal) in the polymerization system.

The molar ratio of the ionized ionic compound (D) to the metallocene compound (B) in the polymerization system (the ionized ionic compound (D)
/ Metallocene compound (B)) in an amount of 0.1 to 20, preferably 1 to 10.

When the organoaluminum compound (E) is used, it is used in an amount of usually about 0 to 5 mmol / liter (polymerization volume), preferably about 0 to 2 mmol / liter.

The copolymerization reaction for producing the ethylene / aromatic vinyl compound copolymer usually has a temperature of -30 to +25.
0 ° C., preferably 0-200 ° C., pressure above 0 to 8
0 kg / cm ² (gauge pressure), preferably more than 0 ～50K
g / cm ² (gauge pressure).

The reaction time (average residence time when the copolymerization is carried out by a continuous method) varies depending on conditions such as the catalyst concentration and the polymerization temperature, but is usually 5 minutes to 3 hours, preferably 10 minutes to 3 hours. 1.5 hours.

In producing the ethylene / aromatic vinyl compound copolymer, ethylene and the aromatic vinyl compound are supplied to the polymerization system in such an amount that a copolymer having the above specific composition can be obtained. . Further, upon copolymerization, a molecular weight regulator such as hydrogen may be used.

When ethylene and an aromatic vinyl compound are copolymerized as described above, an ethylene / aromatic vinyl compound copolymer is usually obtained as a polymerization solution containing the same. This polymerization solution is treated by a conventional method to obtain an ethylene / aromatic vinyl compound copolymer. The thus obtained ethylene / aromatic vinyl compound copolymer having the above physical properties is used alone or in combination of two or more, and used as an electrical insulator.

The ethylene / aromatic vinyl compound copolymer of the present invention can be blended with an ethylene polymer to form a composition for an electric insulator, and this composition can be used as an electric insulator. In this case, the composition contains the content of the structural unit derived from the aromatic vinyl compound in the total of the structural unit constituting the ethylene / aromatic vinyl compound copolymer and the structural unit constituting the ethylene-based polymer (hereinafter referred to as composition Product may be referred to as aromatic vinyl compound content) of 0.05 to 3 mol%, preferably 0.05 to 1.3 m
ol%, a composition having a crystallinity of 40% or more, preferably 45% or more is used.

In such a composition, the chain structure content of the aromatic vinyl compound / aromatic vinyl compound of the ethylene / aromatic vinyl compound copolymer is 1% based on the total structural units derived from the aromatic vinyl compound. Below, preferably 0.1% or less is preferable.

The ethylene / aromatic vinyl compound copolymer has a B value of 0.90 to 2.00, preferably 0.95 to 2.00.
It is preferably 1.50, more preferably 1.00 to 1.45, particularly preferably 1.02 to 1.40.

The intrinsic viscosity [η] of the ethylene / aromatic vinyl compound copolymer measured in decalin at 135 ° C. is 0.1 to 10 dl / g, preferably 0.2 to 8 dl / g.
Is preferred.

In the above composition, as the ethylene / aromatic vinyl compound copolymer to be blended with the ethylene polymer, those having an aromatic vinyl compound content or crystallinity within the above-mentioned range are used. It is also possible to use ones outside the range, or to use mixtures thereof. In short, the physical properties of the composition only need to be in the above-mentioned range.

When the content of the aromatic vinyl compound and the crystallinity of the composition are within the above ranges, the reduction of the dielectric breakdown voltage due to the repeated impulse is improved, and the number of times of application of the repeated impulse until the dielectric breakdown occurs is extended. The resulting composition is obtained. Among the compositions in which the aromatic vinyl compound content and the crystallinity of the composition are within the above range, when the aromatic vinyl compound / aromatic vinyl compound chain structure content is within the above range, the dielectric breakdown voltage due to the repeated impulse is reduced. A composition is obtained in which the reduction is particularly improved and the number of times of application of repetitive impulses until dielectric breakdown occurs is greatly extended.

The ethylene polymer blended with the ethylene / aromatic vinyl compound copolymer is an ethylene polymer which does not belong to the ethylene / aromatic vinyl compound copolymer, for example, polyethylene, ethylene and carbon number 3 ~
And a copolymer of ethylene and a polar monomer. Specific ethylene polymers include the following homopolymers, copolymers, and mixtures thereof.

(1) Density of 0.968 to 0.910 g /
High, medium or low density polyethylene homopolymers up to cm ³ and modifications thereof. (2) ethylene and 10 to 30 mol% of other carbon atoms of 3 to 30
And a modified product thereof with an α-olefin. (3) Other carbon number of 3 to 30 of 10 mol% or less with ethylene
Copolymer of α-olefin and non-conjugated polyene. (4) A copolymer of ethylene and 10 mol% or less of another polar group-containing monomer.

Examples of the α-olefin include ethylene,
Examples include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene and the like. Examples of the polar group-containing monomer include vinyl acetate, acrylic acid, ethyl acrylate, methacrylic acid, ethyl methacrylate, maleic acid, and maleic anhydride. Further, as the non-conjugated polyene,
Examples thereof include dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylene norbornene, and ethylidene norbornene. Examples of the modified product include a modified product modified with an unsaturated carboxylic acid such as acrylic acid and maleic anhydride or a derivative thereof. (1)-
Among the ethylene polymers of (4), the ethylene polymer of (1) or (4) is preferable, and a composition having particularly good moldability can be obtained by blending these.

The amount of the ethylene-based polymer may be such that the physical properties of the composition satisfy the above-mentioned physical properties. Usually, the ethylene-aromatic vinyl compound copolymer (X) and the ethylene-based (X) in weight ratio with the polymer (Y)
/ (Y) = 99/1 to 20/80, preferably 99/1
It is desirable to blend them in a ratio of 50/50.

Further, the ethylene / aromatic vinyl compound copolymer and the composition of the present invention can be used as an electric insulator in a crosslinked state. The crosslinked product of the ethylene / aromatic vinyl compound copolymer or the composition of the present invention has a further improved reduction in the breakdown voltage due to repeated impulses as compared with the crosslinked product before crosslinkage, and furthermore, the repetition until the breakdown occurs. The number of times of application of the impulse is further extended.

As a method for crosslinking the ethylene / aromatic vinyl compound copolymer and the composition of the present invention, known methods can be adopted, for example, a method by irradiating with γ rays or an electron beam, or a method using an organic peroxide. can give.

Examples of the organic peroxide include dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 2,5- Dimethyl-2,5-
Di- (tert-butylperoxy) hexyne-3,
1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, n-
Butyl-4,4-bis (tert-butylperoxy)
Valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate,
tert-butyl perbenzoate, tert-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, tert-butyl cumyl peroxide and the like.

Among these, from the viewpoint of odor and scorch stability, 2,5-dimethyl-2,5-di- (tert-
Butylperoxy) hexane, 2,5-dimethyl-2,
5-di- (tert-butylperoxy) hexyne-
3,1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane,
n-Butyl-4,4-bis (tert-butylperoxy) valerate is preferred, and 1,3-bis (te
Most preferred is (rt-butylperoxyisopropyl) benzene.

In crosslinking using the above organic peroxide, sulfur, p-quinonedioxime, p, p'-dibenzoylquinonedioxime, N-methyl-N-4-dinitrosoaniline, nitrosobenzene , Diphenylguanidine, trimethylolpropane-N, N'-m-phenylenedimaleimide, etc .; peroxy crosslinking aids; divinylbenzene, triallyl cyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylol Polyfunctional methacrylate monomers such as propane trimethacrylate and allyl methacrylate; and polyfunctional vinyl monomers such as vinyl butyrate and vinyl stearate can be used in combination.

The ethylene / aromatic vinyl compound copolymer, the composition and the crosslinked product of the present invention have an improved reduction of the breakdown voltage due to the repeated impulse, and the number of times of the repeated impulse application until the dielectric breakdown occurs can be extended. It is used as an electrical insulator because of its excellent electrical insulation properties. Specifically, it can be used as a covering material for electric wires. In this case, it can be used as a covering material for electric wires of both AC and DC power transmission cables.

When using the ethylene / aromatic vinyl compound copolymer, the composition and the crosslinked product thereof of the present invention as an electric insulator, an organic or inorganic filler, an antioxidant, a lubricant or the like may be used according to the purpose of use. , UV inhibitors, copper harm inhibitors, various organic or inorganic pigments, neutralizers, foaming agents, plasticizers, foam inhibitors, flame retardants, nucleating agents, flow improvers,
Weld strength improvers and the like can be added as long as the object of the present invention is not impaired. In addition, other resins, such as polypropylene and polybutene, as long as the object of the present invention is not impaired, that is, in a range not impairing electric insulation properties and the like.
Poly α-olefins such as poly 4-methylpentene-1;
Polyester, polyamide, polycarbonate, polymethyl (meth) acrylate, ABS resin, elastomer, polyvinyl chloride, etc. may be added and used.

The covering material for electric wires of the present invention is characterized in that
It is a covering material for electric wires comprising an aromatic vinyl compound copolymer, a composition, a cross-linked product, or a mixture of other additives as necessary.

The electric wire of the present invention is obtained by covering a conductor with the above-mentioned electric wire covering material, and can be used as an AC power transmission cable, a DC power transmission cable, or the like.

[0126]

The ethylene / aromatic vinyl compound copolymer for an electric insulator of the present invention is copolymerized in the presence of a metallocene catalyst, and furthermore, the content and crystallinity of the aromatic vinyl compound are within specific ranges. , The reduction of the dielectric breakdown voltage due to the repeated impulse has been improved, and the number of application of the repeated impulse until the dielectric breakdown occurs has been extended.
Excellent electrical insulation properties.

Since the composition for electrical insulation of the present invention contains the above-mentioned aromatic vinyl compound copolymer and ethylene-based polymer, the reduction of the dielectric breakdown voltage due to repeated impulses is improved, and dielectric breakdown occurs. It has excellent electrical insulation properties, such as an increase in the number of times of application of repeated impulses up to.

The covering material for electric wires of the present invention comprises the above copolymer,
Since it contains the composition or a crosslinked product thereof, it has excellent electrical insulation properties, such as improved reduction of dielectric breakdown voltage due to repeated impulses and extension of the number of repeated impulses until dielectric breakdown occurs. .

Since the electric wire of the present invention is covered with the above-mentioned electric wire covering material, the reduction of the dielectric breakdown voltage due to the repeated impulse is improved, and the number of times of applying the repeated impulse until the dielectric breakdown occurs is extended. It has excellent electrical insulation properties and can be used stably for a long time.

[0130]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments. Example 1 A glass 1 liter reactor equipped with a cooling tube and a stirring device was sufficiently replaced with nitrogen, and 499.5 ml of toluene,
0.5 ml of styrene was charged and saturated with ethylene while stirring. Then, the temperature inside the system was raised to 35 ° C., and 9 mM of methylaluminoxane (10% by weight toluene solution, manufactured by Tosoh Akzo Co., Ltd.) and (t-butylamido) dimethyl (tetramethyl-η ⁵ -cyclopentadienyl) silanetitanium dichloride were added. 03 mM (0.01 mM toluene solution) was added. The polymerization was carried out at 40 ° C. for 75 minutes while continuously supplying 100 NL / hr of ethylene.

After the polymerization, isobutyl alcohol 250
The reaction mixture containing isobutyl alcohol was transferred to a separatory funnel, washed twice with 250 ml of water, and separated into oil and water. Then, the oil layer was added to 3 liters of methanol to precipitate a polymer. The precipitated polymer was vacuum-dried at 130 ° C. for 12 hours to obtain a polymer 1 having a styrene content of 0.3 mol%.
4.8 g were obtained.

The ethylene / styrene copolymer (1) obtained as described above was pressed at 200 ° C. for 6 minutes with residual heat.
After forming under pressure for 4 minutes, the sheet was cooled by a press at 25 ° C. for 5 minutes to prepare a 45 × 45 × 1 mm sheet, and the breakdown voltage at 25 ° C. was measured. Further, an internal conductive layer was formed on a 1-mm single-wire conductor, and an insulating layer (thickness 1.5 mm) of the ethylene / styrene copolymer (1) was formed therearound. The cable was subjected to a lightning impulse test (100 kV applied at 5 minute intervals). Table 1 shows the composition and electrical properties of the obtained ethylene / styrene copolymer (1). The styrene content and the styrene-styrene chain structure content of the copolymer were determined by ¹³ C NMR. The crystallinity was determined by DSC.

Example 2 An ethylene / styrene copolymer (2) having a styrene content of 1.1 mol% was obtained in the same manner as in Example 1 except that 2.0 ml of styrene was charged. Table 1 shows the composition and electrical properties of the ethylene / styrene copolymer (2).

Example 3 An ethylene / styrene copolymer (3) having a styrene content of 2.3 mol% was obtained in the same manner as in Example 1 except that 5.0 ml of styrene was charged. Table 1 shows the composition and electrical characteristics of the ethylene / styrene copolymer (3).

Example 4 An ethylene / styrene copolymer (4) was prepared in the same manner as in Example 1 except that the catalyst was changed to isopropylidenebis (indenyl) zirconium dichloride synthesized by a known method.
I got Table 1 shows the composition and electrical properties of the ethylene / styrene copolymer (4).

Comparative Example 1 The procedure of Example 1 was repeated except that styrene was not charged.
Polyethylene (5) having a styrene content of 0 mol% was obtained.
Table 2 shows the composition and electrical characteristics of this polyethylene (5).

Comparative Example 2 An ethylene / styrene copolymer (6) having a styrene content of 3.6 mol% was polymerized in the same manner as in Example 1 except that 7.0 ml of styrene was charged. Table 2 shows the composition and electrical characteristics of the ethylene / styrene copolymer (6).

Comparative Example 3 A predetermined amount of ethylene, styrene and n-heptane as a chain transfer agent were charged into an autoclave equipped with a stirring blade, which was sufficiently substituted with nitrogen and ethylene, and di-t-butyl peroxide as an initiator was further added. At a pressure of 1900
The polymerization was carried out under the polymerization conditions of kg / cm ² , a polymerization temperature of 180 ° C. and a polymerization time of 40 minutes. The produced polymer was purified and dried to obtain an ethylene / styrene copolymer (7) having a styrene content of 2.1 mol%. Table 2 shows the composition and electrical properties of the ethylene / styrene copolymer (7).

Example 5 0.24,4′-thiobis (6-tert-butyl-4-methylphenol) was added to the ethylene / styrene copolymer (2) of Example 2 as a stabilizer (antiaging agent). After kneading with a weight part Banbury mixer, the mixture was molded into a predetermined shape, and irradiated with 5 kGy of γ-ray to be crosslinked to obtain a crosslinked ethylene / styrene copolymer (8). Table 3 shows the electrical properties of this ethylene / styrene copolymer (8).

Example 6 0.24 of 4,4'-thiobis (6-t-butyl-4-methylphenol) was added to the ethylene / styrene copolymer (2) of Example 2 as a stabilizer (antiaging agent). Then, 2.0 parts by weight of dicumyl peroxide and 2.0 parts by weight of dicumyl peroxide were added, kneaded with a Banbury mixer, molded into a predetermined shape, and crosslinked at 170 ° C. for 15 minutes to obtain a crosslinked ethylene / styrene copolymer (9). Table 3 shows the electrical properties of this ethylene / styrene copolymer (9).

Comparative Example 4 In place of the ethylene / styrene copolymer (9) of Example 5, a melt index at 190 ° C. of 0.6 g / 10 minutes was used.
Apart from using LDPE with a density of 0.925 g / cm ³ ,
Crosslinked LDPE (10) was obtained in the same manner as in Example 6. Table 3 shows the electrical properties of the crosslinked LDPE (10).

[0142]

[Table 1]

[0143]

[Table 2]

[0144]

[Table 3]

Notes to Tables 1 and 2 * 1 St: Styrene * 2 Crystallinity: The endothermic amount obtained from the area of the endothermic peak at the melting point of DSC was divided by the crystallization energy of polyethylene to obtain the weight% of the crystal part. * 3 St.St chain structure content: value obtained by measuring ¹³ C NMR * 4 Repeated impulse: (number of times dielectric breakdown occurred -1)
The value of the ratio of the polymer of each example to the case where the value of the polymer of Comparative Example 1 was set to 1.0. * 5 Dielectric breakdown voltage: a value measured in accordance with JIS-K-6911

Example 7 A glass 1 liter reactor equipped with a cooling tube and a stirrer was sufficiently replaced with nitrogen, charged with 499.5 ml of toluene and 1.0 ml of styrene, and saturated with ethylene while stirring. Next, the temperature inside the system was raised to 35 ° C., and methylaluminoxane (10 wt% toluene solution manufactured by Tosoh Akzo Co., Ltd.) was used.
9 mM, (t-butylamido) dimethyl (tetramethyl-
eta ⁵ - was added cyclopentadienyl) silane titanium dichloride 0.03 mM (0.01 mM toluene solution). The polymerization was carried out at 40 ° C. for 75 minutes while continuously supplying 100 NL / hr of ethylene.

After completion of the polymerization, isobutyl alcohol 250
The reaction mixture containing isobutyl alcohol was transferred to a separatory funnel, washed twice with 250 ml of water, and separated into oil and water. Then, the oil layer was added to 3 liters of methanol to precipitate a polymer. The precipitated polymer was vacuum-dried at 130 ° C. for 12 hours to obtain a polymer 1 having a styrene content of 0.8 mol%.
7.5 g were obtained.

To 90 parts by weight of the ethylene / styrene copolymer (11) obtained as described above, a melt index at 190 ° C. of 0.6 g / 10 minutes and a density of 0.925 g / c
10 parts by weight of LDPE (a) of m ^3, as a stabilizer (antioxidant) 4,4'-thiobis (6-t-butyl-4
Methyl phenol) and 2.0 parts by weight of dicumyl peroxide, and kneaded with a Banbury mixer.
I put out the sheet. After that, press molding with a 180 ° C. press with residual heat for 6 minutes, cooling with a 25 ° C. press for 5 minutes, and 45 ×
A sheet of 45 × 1 mm was prepared, and the breakdown voltage at 25 ° C. was measured.

An inner conductive layer is formed on a 1 mm single-wire conductor, and the above-mentioned ethylene / styrene copolymer (11)
Insulating layer (thickness 1.5)
mm). This cable was subjected to a lightning impulse test (100 kV applied at 5 minute intervals). Table 4 shows the composition of the obtained ethylene / styrene copolymer (11), and Table 5 shows the electrical properties of the blend.

Example 8 An ethylene / styrene copolymer (12) having a styrene content of 3.8 mol% was obtained in the same manner as in Example 7 except that 7.0 ml of styrene was charged. To 50 parts by weight of the ethylene / styrene copolymer (12), 50 parts by weight of an ethylene / 1-octene copolymer (b) containing a melt index of 1.0 g / 10 minutes at 190 ° C. and 2 mol% of 1-octene,
As a stabilizer (antiaging agent), 4,4′-thiobis (6-
(t-butyl-4-methylphenol) was added in an amount of 0.2 part by weight and dicumyl peroxide (2.0 parts by weight), and the ethylene-styrene copolymer (12) and the ethylene / 1-octene copolymer were added in the same manner as in Example 7. A blend with the polymer (b) was prepared. Table 5 shows the electrical properties of the blend.

Comparative Example 5 The procedure of Example 7 was repeated except that styrene was not charged.
Polyethylene (13) was obtained. This polyethylene (1
3) A melt index at 190 ° C. of 0 to 50 parts by weight.
LDPE with a density of 6 g / 10 min and a density of 0.925 g / cm ³
50 parts by weight of (a) and 4, as a stabilizer (antiaging agent)
A polyethylene blend was prepared in the same manner as in Example 6, except that 0.2 part by weight of 4'-thiobis (6-t-butyl-4-methylphenol) and 2.0 parts by weight of dicumyl peroxide were added. Table 4 shows the composition of the obtained polyethylene (13), and Table 5 shows the electrical properties of the blend.

Comparative Example 6 An ethylene / styrene copolymer (14) having a styrene content of 13.4 mol% was obtained in the same manner as in Example 7 except that 35.0 ml of styrene was charged. 50 parts by weight of the ethylene / styrene copolymer (14) were added at 190 ° C. with a melt index of 0.6 g / 10 minutes and a density of 0.925 g / cm ^3.
LDPE (a) of 50 parts by weight, stabilizer (antiaging agent)
Of 4,4'-thiobis (6-t-butyl-4-methylphenol) and 2.0 parts by weight of dicumyl peroxide.
A blend of the styrene copolymer (14) and the LDPE (a) was prepared. Table 4 shows the composition of the obtained ethylene / styrene copolymer (14), and Table 5 shows the electrical properties of the blend.
Shown in

Comparative Example 7 A predetermined amount of ethylene, styrene and n-heptane as a chain transfer agent were charged into an autoclave equipped with a stirring blade, which was sufficiently substituted with nitrogen and ethylene, and further, di-t-butyl peroxide as an initiator was added. At a pressure of 1900
The polymerization was carried out under the polymerization conditions of kg / cm ² , a polymerization temperature of 180 ° C. and a polymerization time of 40 minutes. The produced polymer was purified and dried to obtain an ethylene / styrene copolymer (15) having a styrene content of 4.0 mol%.

This ethylene / styrene copolymer (15)
To 50 parts by weight, a melt index of 0.6 g at 190 ° C.
/ 10 min, density 0.925 g / cm ³ of LDPE (a)
50 parts by weight, 4,4′- as a stabilizer (antiaging agent)
0.2 parts by weight of thiobis (6-t-butyl-4-methylphenol) and 2.0 parts by weight of dicumyl peroxide were added, and in the same manner as in Example 7, ethylene-styrene copolymer (15) and LDPE ( A blend with a) was prepared.
Table 4 shows the composition of the obtained ethylene / styrene copolymer (15), and Table 5 shows the electrical properties of the blend.

[0155]

[Table 4] * 1 St: Styrene * 2 Crystallinity: See Table 1 * 3 St.St chain structure content: See Table 1

[0156]

[Table 5]

Notes to Table 4 * 1 St: styrene * 2 Total styrene: styrene content in the composition * 3 Crystallinity of the composition: crystallinity of the entire composition * 4 Repeated impulse: see Table 1 * 5 Dielectric breakdown voltage: See Table 1

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08F 212: 00) (72) Inventor Kenichi Morizono 6-1-2, Waki, Waki-cho, Kuga-gun, Yamaguchi Prefecture Mitsui Petrochemical Industry Co., Ltd. Inside

Claims (13)

[Claims] 1. A copolymer obtained by copolymerizing ethylene and an aromatic vinyl compound in the presence of a metallocene catalyst (A), wherein the content of a structural unit derived from the aromatic vinyl compound is 0.05. An ethylene / aromatic vinyl compound copolymer for an electrical insulator, characterized by having a crystallinity of at least 3 mol% and a crystallinity of at least 40%. 2. The ratio of a structural unit constituting a chain structure in which two or more structural units derived from an aromatic vinyl compound are continuous is 1% or less with respect to all structural units derived from an aromatic vinyl compound. The copolymer according to claim 1, characterized in that: 3. The copolymer according to claim 1, wherein the aromatic vinyl compound is styrene. 4. The metallocene catalyst (A) contains a bridge type metallocene compound.
The polymer according to any one of the above. 5. The polymer according to claim 4, wherein the metallocene compound is isopropylidenebis (indenyl) zirconium dichloride. 6. A composition comprising an ethylene / aromatic vinyl compound copolymer obtained by copolymerizing ethylene and an aromatic vinyl compound in the presence of a metallocene catalyst (A), and an ethylene-based polymer. The content of the structural unit derived from the aromatic vinyl compound in the total of the structural unit constituting the ethylene / aromatic vinyl compound copolymer and the structural unit constituting the ethylene polymer is 0.05 to 3 mol%. A composition for an electrical insulator, which has a crystallinity of 40% or more. 7. The ethylene / aromatic vinyl compound copolymer has a structure in which the ratio of structural units constituting a chain structure in which two or more structural units derived from the aromatic vinyl compound are continuous is a total structure derived from the aromatic vinyl compound. The composition according to claim 6, wherein the composition is 1% or less based on the unit. 8. The composition according to claim 6, wherein the aromatic vinyl compound is styrene. 9. The metallocene catalyst (A) contains a bridge type metallocene compound.
The composition according to any one of the above. 10. The polymer according to claim 9, wherein the metallocene compound is isopropylidenebis (indenyl) zirconium dichloride. 11. A covering material for electric wires, comprising the copolymer according to claim 1 or a crosslinked product thereof. 12. A covering material for electric wires, comprising the composition according to claim 6 or a crosslinked product thereof. 13. An electric wire coated with the electric wire covering material according to claim 11. Description: