JP2001064313A - Catalyst composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a catalyst composition for copolymerization of a conjugated diene with an aromatic vinyl compound, a co-catalyst included in the catalyst composition and a novel copolymer produced by using the catalyst composition. SOLUTION: The catalyst composition is the one for copolymerization of a conjugated diene with an aromatic vinyl compound and includes (A) a methallocene complex of a rare earth metal compound (for example, a samarium complex, or the like) and (B) an ionic compound comprising a non-coordinating anion and a cation [triphenyl carbonium tetrakis (pentafluorophenyl) borate, or the like] and/or aluminoxane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst composition for copolymerizing a conjugated diene and an aromatic vinyl compound, and a cocatalyst contained in the catalyst composition. The present invention also relates to a method for producing a copolymer of a conjugated diene and an aromatic vinyl compound using the catalyst composition, and a novel copolymer obtained by the production method.

[0002]

2. Description of the Related Art Many catalysts for copolymerizing a conjugated diene and an aromatic vinyl compound have been proposed so far and play an extremely important role industrially. In particular, to obtain copolymers of conjugated dienes and aromatic vinyl compounds with improved thermal and mechanical properties, research was conducted on copolymerization catalysts that are controlled to have a high cis 1,4 bond content. -Has been developed.

[0003] For example, a composite catalyst system containing a transition metal compound such as nickel, cobalt, titanium or the like as a main component (Industrial Chemistry Magazine, 72, 2081, 1969; Plast. Kautsch., 40, 356, 19)
93; Makromol. Chem. Phys., 195, 2623, 199), and a composite catalyst system containing a rare earth metal compound such as neodymium or gadolinium (Macromol. Rapid Commun. 1).
6, 563, 1992; J. Polym. Sci., Par A; Polym. Chem.,
32, 1195, 1994; Polymer, 37, 349, 1996). In these catalyst systems, some high cis 1,
4 Although controllability was exhibited, it was not possible to produce a polymer having a high molecular weight, a narrow molecular weight distribution, and a random monomer composition in the copolymer.

[0004]

An object of the present invention is to provide a catalyst for copolymerizing a conjugated diene and an aromatic vinyl compound. More specifically, a polymer having a high content of the cis 1,4-structure in the microstructure and having a high molecular weight and a narrow molecular weight distribution, preferably a random copolymer having the above characteristics, is produced. To provide a catalyst for use. Another object of the present invention is to provide a copolymer having the above characteristics and a method for producing the same.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a rare earth metallocene-type polymerization catalyst and an ionic catalyst composed of a non-coordinating anion and a cation. By using a catalyst composition in which a compound and / or a co-catalyst containing an aluminoxane are used in combination, it is possible to efficiently copolymerize a conjugated diene and an aromatic vinyl compound, and to use the above-described catalyst composition for copolymerization. By using, conjugated dienes and an aromatic vinyl compound are copolymerized to form cis 1,1 in the microstructure.
It has been found that a copolymer having a very high content of 4-structure and having a high molecular weight and a narrow molecular weight distribution, preferably a random copolymer having a random monomer composition can be produced. The present invention has been completed based on these findings.

That is, the present invention provides a catalyst composition for copolymerizing a conjugated diene and an aromatic vinyl compound, comprising: (A) a metallocene complex of a rare earth metal compound;
And (B) an ionic compound comprising a non-coordinating anion and a cation and / or an aluminoxane. According to a preferred embodiment of the present invention,
The above catalyst composition, wherein the metallocene complex is a samarium complex; the ionic compound is triphenylcarbonium tetrakis (pentafluorophenyl) borate, triphenylcarbonium tetrakis (tetrafluorophenyl)
The above catalyst composition which is borate, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, 1,1′-dimethylferrocenium tetrakis (pentafluorophenyl) borate;
The above catalyst composition comprising an organometallic compound of a Group III element is provided.

From another viewpoint, a co-catalyst to be used together with a catalyst for copolymerizing a conjugated diene containing a metallocene-type complex of a rare-earth metal compound with an aromatic vinyl compound is provided. A co-catalyst comprising an ionic compound comprising a cation and / or an aluminoxane is provided by the present invention. From still another viewpoint, a method of copolymerizing a conjugated diene and an aromatic vinyl compound in the presence of the above-described polymerization catalyst composition; and a method of copolymerizing a conjugated diene and an aromatic vinyl compound in the presence of the above-mentioned polymerization catalyst composition Provided is a copolymer obtainable by copolymerizing a compound.
In addition to these inventions, the content of the cis 1,4 structure in the microstructure is 80 mol% or more, preferably 90 mol% or more,
Particularly preferably at least 95 mol%, the molecular weight Mn is 10,000
Or more, preferably 20,000 or more, more preferably 50,000 or more, particularly preferably 100,000 or more, molecular weight distribution Mw
/ Mn is 2.50 or less, preferably 2.00 or less, more preferably
There is provided a copolymer of 1.80 or less, particularly preferably 1.50 or less. This copolymer can be produced by copolymerizing a conjugated diene and an aromatic vinyl compound in the presence of the above-mentioned catalyst composition for copolymerization.

[0008]

The metallocene complex of the DETAILED DESCRIPTION OF THE INVENTION rare earth metal compounds, for example, the general formula _{(I): R a MX b} · L c or the general formula _{(II): R a MX b} QX b ( wherein, M Represents a rare earth metal; R represents a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, a fluorenyl group, or a substituted fluorenyl group; X represents a hydrogen atom, a halogen atom, an alkoxide group, a thiolate L represents a Lewis basic compound; Q represents a Group III element of the periodic table; a represents an integer of 1, 2, or 3; B; 0, 1,
Or c represents an integer of 2; c represents an integer of 0, 1, or 2), and a divalent or trivalent rare earth metal compound represented by the formula:

In the general formula (I), as the rare earth metal represented by M, an element having an atomic number of 57 to 71 in the periodic table can be used. Specific examples of rare earth metals include, for example, lanthanum, cerium, praseodymium,
Neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium can be mentioned, among which samarium is preferred. When a is 2, two Rs may be the same or different. Similarly, when b or c is 2, two X or L may be the same or different.

The type, number and position of the substituents in the substituted cyclopentadienyl group, the substituted indenyl group or the substituted fluorenyl group are not particularly restricted but include, for example, methyl group, ethyl group, n-propyl group and isopropyl group. , N-butyl group, isobutyl group, sec-butyl group, tert-
In addition to a butyl group, a hexyl group, a phenyl group, a benzyl group and the like, a hydrocarbon group containing a silicon atom such as a trimethylsilyl group can be exemplified. R may be bonded to a part of X by a cross-linking group such as a dimethylsilyl group, a dimethylmethylene group, a methylphenylmethylene group, a diphenylmethylene group, an ethylene group, or a substituted ethylene group. They may be bonded by a cross-linking group such as a silyl group, a dimethylmethylene group, a methylphenylmethylene group, a diphenylmethylene group, an ethylene group, and a substituted ethylene group.

Specific examples of the substituted cyclopentadienyl group include, for example, methylcyclopentadienyl group, benzylcyclopentadienyl group, vinylcyclopentadienyl group, 2-methoxyethylcyclopentadienyl group, and trimethylsilylcyclo group. Pentadienyl group, tert-butylcyclopentadienyl group, ethylcyclopentadienyl group, phenylcyclopentadienyl group, 1,2-dimethylcyclopentadienyl group, 1,3-dimethylcyclopentadienyl group, 1,3-di (tert-butyl) cyclopentadienyl group, 1,2,3-trimethylcyclopentadienyl group, 1,2,3,
4-tetramethylcyclopentadienyl group, pentamethylcyclopentadienyl group, 1-ethyl-2,3,4,5-tetramethylcyclopentadienyl group, 1-benzyl-2,3,4,5- Tetramethylcyclopentadienyl group, 1-phenyl-2,3,
4,5-tetramethylcyclopentadienyl group, 1-trimethylsilyl-2,3,4,5-tetramethylcyclopentadienyl group, 1-trifluoromethyl-2,3,4,5-tetramethylcyclopenta And a dienyl group. Specific examples of the substituted indenyl group include, for example, a 1,2,3-trimethylindenyl group, a heptamethylindenyl group, and a 1,2,4,5,6,7-hexamethylindenyl group. R is preferably a pentamethylcyclopentadienyl group.

The alkoxide group represented by X includes aliphatic alkoxy groups such as methoxy group, ethoxy group, propoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, phenoxy group, 2,6 -Di-tert-butylphenoxy group, 2,6-diisopropylphenoxy group,
Aryl oxide groups such as 2,6-dineopentylphenoxy group, 2-tert-butyl-6-isopropylphenoxy group, 2-tert-butyl-6-neopentylphenoxy group, and 2-isopropyl-6-neopentylphenoxy group Or a 2,6-di-tert-butylphenoxy group.

The thiolate group represented by X includes thiomethoxy, thioethoxy, thiopropoxy, thion-
Butoxy group, thioisobutoxy group, thiosec-butoxy group, aliphatic thiolate group such as thiotert-butoxy group,
Thiophenoxy group, 2,6-di-tert-butylthiophenoxy group, 2,6-diisopropylthiophenoxy group, 2,6-dineopentylthiophenoxy group, 2-tert-butyl-6-isopropylthiophenoxy group, 2-tert-butyl-6-thioneopentylphenoxy group, 2-isopropyl-6-thioneopentylphenoxy group, or any of arylthiolate groups such as 2,4,6-triisopropylthiophenoxy group,
A 2,4,6-triisopropylthiophenoxy group is preferred.

Examples of the amide group include an aliphatic amide group such as a dimethylamide group, a diethylamide group and a diisopropylamide group, a phenylamide group, a 2,6-di-tert-butylphenylamide group, and a 2,6-diisopropylphenylamide group. ,
2,6-dineopentylphenylamide group, 2-tert-butyl-
Arylamide groups such as 6-isopropylphenylamide group, 2-tert-butyl-6-neopentylphenylamide group, 2-isopropyl-6-neopentylphenylamide group, and 2,4,6-tert-butylphenylamide group Or a 2,4,6-tert-butylphenylamide group is preferred.

The halogen atom represented by X is a fluorine atom,
Any of a chlorine atom, a bromine atom and an iodine atom may be used, but a chlorine atom and an iodine atom are preferred. 1 to 20 carbon atoms
Specific examples of the hydrocarbon group of, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group,
Isobutyl group, sec-butyl group, tert-butyl group, neopentyl group, hexyl group, linear or branched aliphatic hydrocarbon group such as octyl, phenyl group, tolyl group, aromatic hydrocarbon group such as naphthyl group, In addition to an aralkyl group such as a benzyl group, a hydrocarbon group containing a silicon atom such as a trimethylsilylmethyl group and a bistrimethylsilylmethyl group may be used. Among these, a methyl group, an ethyl group, an isobutyl group, a trimethylsilylmethyl group and the like are preferable. X is preferably a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms.

The Lewis basic compound represented by L is not particularly limited as long as it is a Lewis basic compound capable of coordinating a metal with a counter electron, and may be either an inorganic compound or an organic compound. As Lewis basic compounds, for example, ether compounds, ester compounds, ketone compounds,
An amine compound, a phosphine compound, a silyloxy compound, or the like can be used, but is not limited thereto. In the general formula (II), Q represents a Group III element in the periodic table, and specific examples of the element include boron, aluminum, and gallium, with aluminum being preferred.

Specific examples of the metallocene complex of the rare earth metal compound represented by the formula (I) include, for example, bispentamethylcyclopentadienylbistetrahydrofuransamarium, methylbispentamethylcyclopentadienyltetrahydrofuransamarium, chlorobis Pentamethylcyclopentadienyl tetrahydrofuransamarium, or iodobispentamethylcyclopentadienyl tetrahydrofuransamarium and the like, the formula (II)
As a specific example of the metallocene complex of the rare earth metal compound represented by the following formula, for example, dimethylaluminum (μ-dimethyl) bis (pentamethylcyclopentadienyl) samarium and the like can be mentioned.

The ionic compound used as the co-catalyst is not particularly limited as long as it comprises a non-coordinating anion and a cation. For example, the ionic compound can react with the rare earth metal compound to form a cationic transition metal compound. Ionic compounds and the like can be mentioned. Non-coordinating anions include, for example, tetra (phenyl) borate, tetrakis (monofluorophenyl) borate, tetrakis (difluorophenyl) borate, tetrakis (trifluorophenyl) borate, tetrakis (trifluorophenyl) borate, tetrakis (penta) (Fluorophenyl) borate, tetrakis (tetrafluoromethylphenyl) borate, tetra (tolyl) borate, tetra (xylyl) borate, (triphenyl, pentafluorophenyl) borate, [tris (pentafluorophenyl), phenyl] borate, trideca Hydride
And -7,8-dicarboundecaborate.

Examples of the cation include a carbonium cation, an oxonium cation, an ammonium cation, a phosphonium cation, a cycloheptatrienyl cation, and a ferrocenium cation having a transition metal. Specific examples of the carbonium cation include a trisubstituted carbonium cation such as a triphenylcarbonium cation and a trisubstituted phenylcarbonium cation. Specific examples of the tri-substituted phenylcarbonium cation include a tri (methylphenyl) carbonium cation and a tri (dimethylphenyl) carbonium cation. Specific examples of the ammonium cation include trimethylammonium cation, triethylammonium cation, tripropylammonium cation, tributylammonium cation, trialkylammonium cation such as tri (n-butyl) ammonium cation, N, N-diethylanilinium cation, N And N, N-dialkylanilinium cations such as N, 2,4,6-pentamethylanilinium cation, dialkylammonium cations such as di (isopropyl) ammonium cation and dicyclohexylammonium cation. Specific examples of the phosphonium cation include triarylphosphonium cations such as triphenylphosphonium cation, tri (methylphenyl) phosphonium cation, and tri (dimethylphenyl) phosphonium cation.

As the ionic compound, a non-coordinating anion and a cation which are arbitrarily selected and combined can be preferably used. For example, ionic compounds include triphenylcarbonium tetrakis (pentafluorophenyl) borate and triphenylcarbonium tetrakis (tetrafluorophenyl)
Borates, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, 1,1′-dimethylferrocenium tetrakis (pentafluorophenyl) borate and the like are preferable. The ionic compounds may be used alone or in combination of two or more. As a Lewis acid capable of producing a cationic transition metal compound by reacting with a transition metal compound, B (C ₆ F ₅ ) ₃ , Al (C ₆ F ₅ ) ₃ or the like can be used, and these are the ionic compounds described above. May be used in combination.

As the aluminoxane used as a cocatalyst, for example, an aluminoxane obtained by contacting an organic aluminum compound with a condensing agent can be used. More specifically, an aluminoxane represented by the general formula (-Al (R ')) A chain aluminoxane or a cyclic aluminoxane represented by O-) _n can be used. In the above formula, R ′ is a hydrocarbon group having 1 to 10 carbon atoms, and the hydrocarbon group may be substituted with a halogen atom and / or an alkoxy group. n indicates the degree of polymerization, and is preferably 5 or more, more preferably 10 or more. R ′ is a methyl group, an ethyl group, a propyl group,
Examples include an isobutyl group, and a methyl group is preferred. Examples of the organoaluminum compound used as a raw material for the aluminoxane include trialkylaluminums such as trimethylaluminum, triethylaluminum, and triisobutylaluminum, and mixtures thereof. Particularly preferred is trimethylaluminum. Aluminoxane using a mixture of trimethylaluminum and tributylaluminum as a raw material can also be suitably used. Aluminoxanes may be used in combination with ionic compounds.

The catalyst composition of the present invention contains the above-mentioned components (A) and (B), and further contains, as a component (C), Periodic Tables I to III.
It may contain an organometallic compound of a group element. Examples of the organic metal compound include an organic aluminum compound, an organic lithium compound, an organic magnesium compound, an organic zinc compound, an organic boron compound, and the like. More specifically, methyllithium, butyllithium, phenyllithium, benzyllithium, neopentyllithium, trimethylsilylmethyllithium, bistrimethylsilylmethyllithium, dibutylmagnesium, dihexylmagnesium, diethylzinc, dimethylzinc, trimethylaluminum, triethylaluminum, triethylaluminum Isobutyl aluminum, trihexyl aluminum, trioctyl aluminum, tridecyl aluminum, and the like can be used. Further, organic metal halides such as ethyl magnesium chloride, butyl magnesium chloride, dimethyl aluminum chloride, diethyl aluminum chloride, sesquiethyl aluminum chloride, ethyl aluminum dichloride, etc .; and hydrogenated organic metals such as diethyl aluminum hydride and sesquiethyl aluminum hydride. Compounds may be used. You may use these organometallic compounds in combination of 2 or more types.

The above components (A) and
As for the blending ratio of (B), the type of the monomer to be polymerized can be appropriately selected depending on the type and conditions of the reaction. Generally, in a composition containing a rare earth metal compound and an aluminoxane, the components (A): component (B) (molar ratio) are 1: 1 to 1: 1.
0000, preferably 1:10 to 1: 1000, more preferably
1:50 to 1: 500 can be set. In the composition containing the rare earth metal compound and the ionic compound, the component (A):
Component (B) (molar ratio) is from 1: 0.1 to 1:10, preferably 1: 0.
The ratio may be about 2 to 1: 5, more preferably about 1: 0.5 to 1: 2. In the catalyst composition containing the component (C), the mixing ratio (molar ratio) of the rare earth metal compound and the component (C) is, for example, 1: 0.1 to 1: 1000, and preferably 1: 0.2 to 1: 500. And more preferably about 1: 0.5 to 1:50.

The type of the conjugated diene compound monomer copolymerizable by the polymerization method of the present invention is not particularly limited, and examples thereof include 1,3-butadiene, isoprene, 1,3-pentadiene,
2-ethyl-1,3-butadiene, 2,3-dimethylbutadiene,
2-methylpentadiene, 4-methylpentadiene, or 2,
4-hexadiene and the like.
1,3-butadiene is preferred. These monomer components may be used alone or in combination of two or more.

The kind of the aromatic vinyl compound monomer copolymerizable by the polymerization method of the present invention is not particularly limited. For example, styrene, p-methylstyrene, m-methylstyrene,
p-tert-butylstyrene, α-methylstyrene, chloromethylstyrene, p-tert-butoxystyrene, dimethylaminomethylstyrene, dimethylaminoethylstyrene,
Vinyl toluene and the like are used. Of these, styrene is preferred. These monomer components may be used alone or in combination of two or more.

The polymerization method of the present invention may be carried out in the presence or absence of a solvent. When a solvent is used, its type is not particularly limited as long as the solvent is substantially inert in the polymerization reaction and has sufficient solubility in the monomer and the catalyst composition. For example, butane,
Saturated aliphatic hydrocarbons such as pentane, hexane and heptane; saturated alicyclic hydrocarbons such as cyclopentane and cyclohexane; monoolefins such as 1-butene and 2-butene; aromatic hydrocarbons such as benzene and toluene; Methylene,
Examples thereof include halogenated hydrocarbons such as chloroform, carbon tetrachloride, trichloroethylene, perchlorethylene, 1,2-dichloroethane, chlorobenzene, bromobenzene, and chlorotoluene. Of these, toluene is preferable. Further, two or more solvents may be used in combination.

The polymerization temperature in the polymerization method of the present invention is, for example, in the range of -100 to 100 ° C, preferably in the range of -50 to 80 ° C. The polymerization time is, for example, about 1 minute to 50 hours, preferably about 5 minutes to 5 hours. However, these reaction conditions can be appropriately selected according to the type of the monomer and the type of the catalyst composition, and are not limited to the ranges exemplified above. After the polymerization reaction reaches a predetermined polymerization rate, a known polymerization terminator is added to the polymerization system to stop the polymerization, and then the produced copolymer can be separated from the reaction system according to a usual method.

The content of the cis structure in the microstructure of the copolymer of the present invention is usually 80 mol% or more, preferably 90 mol% or more.
mol% or more, particularly preferably 95 mol% or more,
Mn is 10,000 or more, preferably 20,000 or more, more preferably 50,000 or more, particularly preferably 100,000 or more, and the molecular weight distribution Mw / Mn is 2.50 or less, preferably 2.00 or less, more preferably 1.80 or less, and particularly preferably 1.50 or less. is there. Further, the copolymer of the present invention is a random copolymer whose monomer composition shows substantially randomness. Since the copolymer of the present invention is expected to have high thermal properties (thermal stability, etc.) and mechanical properties (tensile modulus, flexural modulus, etc.), it is used for various uses as a polymer material. It is possible to

Hereinafter, the present invention will be described more specifically with reference to Examples, but the scope of the present invention is not limited to these Examples. The microstructure of the polybutadiene in the examples is the peak [ ¹ H obtained by ¹ H NMR and ¹³ C NMR.
NMR: δ 4.8-5.0 (= CH _{2 in} 1,2-vinyl unit), 5.2-
5.8 (-CH = of 1,4-unit and -CH of 1,2-vinyl unit
=), ¹³ C NMR: δ 27.4 (1,4-cis unit), 32.7 (1,4
-Transformer unit), 127.7-131.8 (1,4-unit), 11
3.8-114.8 and 143.3-144.7 (1,2-vinyl unit)], the styrene content was determined by ¹ H NMR peak [δ 4.8-5.0 (butadiene 1,2-vinyl unit) = CH ₂ ), δ 5.2-5.8 (-CH = of 1,4-vinyl and 1,2-vinyl units of butadiene), and δ 6.3-7.3
(Aromatic ring of styrene unit)].
The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) were determined by GPC using polystyrene as a standard substance.

Example 1 Drying well in a glove box under a nitrogen atmosphere
Dimethyl aluminum (μ-
Dimethyl) bis (pentamethylcyclopentadienyl)
0.03 mmol of samarium [(Cp ^* ) ₂ Sm (μ-Me) ₂ AlMe ₂ ] (Cp ^* : pentamethylcyclopentadienyl ligand) was charged and dissolved in 1 ml of toluene. Then, 0.09 mmol of triisobutylaluminum and triphenylcarbonium tetrakis (pentafluorophenyl) borate (Ph ₃ CB (C ₆ F ₅ ) ₄ )
0.03 mmol was added and the bottle was stoppered. Then remove the bottle from the glove box and add 1,3-butadiene
0.97 g and 1.4 ml of styrene were charged, and polymerization was performed at 50 ° C. for 30 minutes. After polymerization, 10 wt% of BHT (2,6-bis (tert-butyl)
The reaction was stopped by adding 10 ml of methanol containing [-4-methylphenol], and the polymer was separated with a large amount of a mixed solvent of methanol / hydrochloric acid and dried at 60 ° C. in vacuo. The yield of the obtained polymer was 21 wt%. The styrene content in the polymer is 4.6 mol%, the microstructure of the butadiene unit has a cis content of 94.6 mol%, and the number average molecular weight is 10 mol%.
1,000 and Mw / Mn were 1.41.

Example 2 0.81 g of 1,3-butadiene and 1.7 ml of styrene were charged, and 50
A polymer was obtained in the same manner as in Example 1, except that the polymerization was carried out at 1 ° C. for 1 hour. The yield of the obtained polymer was 22 wt%. The styrene content in the polymer was 7.2 mol%, the microstructure of the butadiene unit was 95.1 mol%, the number average molecular weight was 78,600, and Mw / Mn was 1.59.

Example 3 0.65 g of 1,3-butadiene and 2.0 ml of styrene were charged, and 50
A polymer was obtained in the same manner as in Example 1, except that the polymerization was carried out at 6 ° C for 6 hours. The yield of the obtained polymer was 20 wt%. The styrene content in the polymer is 11.4 mol%, the microstructure of the butadiene unit has a cis content of 91.7 mol%
The number average molecular weight was 73,900 and Mw / Mn was 1.69.

Example 4 0.49 g of 1,3-butadiene and 2.4 ml of styrene were charged, and 50
A polymer was obtained in the same manner as in Example 1, except that polymerization was carried out at 12 ° C for 12 hours. The yield of the obtained polymer was 23 wt%. The styrene content in the polymer is 19.1 mol%, the microstructure of the butadiene unit has a cis content of 87.4 mol%
The number average molecular weight was 38,700 and Mw / Mn was 1.75.

EXAMPLE 5 0.32 g of 1,3-butadiene and 2.8 ml of styrene were charged, and 50
A polymer was obtained in the same manner as in Example 1, except that polymerization was carried out at 50 ° C for 50 hours. The yield of the obtained polymer was 21 wt%. The styrene content in the polymer is 33.2 mol%, the microstructure of the butadiene unit has a cis content of 80.3 mol%
And the number average molecular weight was 23,400 and Mw / Mn was 2.23.

[0035]

[Table 1]

[0036]

EFFECT OF THE INVENTION The use of the catalyst composition of the present invention makes it possible to obtain from a conjugated diene and an aromatic vinyl compound a random having a very high cis-1,4-structure content in the microstructure, a high molecular weight and a narrow molecular weight distribution. A copolymer can be produced.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J015 DA04 DA05 DA09 DA10 DA37 4J100 AB02Q AB03Q AB04Q AB07Q AS02P AS03P AS04P AS06P BA04Q BA31Q BB01Q BC43Q CA04 DA00 DA01 DA04 DA41 FA10

Claims (9)

[Claims] 1. A catalyst composition for copolymerizing a conjugated diene and an aromatic vinyl compound, comprising: (A) a metallocene complex of a rare earth metal compound; and (B) a non-coordinating anion. A composition comprising an ionic compound composed of a cation and a cation and / or an aluminoxane. 2. The catalyst composition according to claim 1, wherein the metallocene complex is a samarium complex. 3. The method according to claim 1, wherein the ionic compound is triphenylcarbonium tetrakis (pentafluorophenyl) borate,
3. The compound according to claim 1, wherein the compound is triphenylcarbonium tetrakis (tetrafluorophenyl) borate, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, or 1,1'-dimethylferrocenium tetrakis (pentafluorophenyl) borate. 3. The catalyst composition according to item 1. 4. The catalyst composition according to claim 1, further comprising an organometallic compound of an element of Groups I to III of the periodic table. 5. A co-catalyst for use together with a catalyst for copolymerizing a conjugated diene containing a metallocene-type complex of a rare earth metal compound and an aromatic vinyl compound, wherein the ionic catalyst comprises a non-coordinating anion and a cation. A cocatalyst containing a compound and / or an aluminoxane. 6. A method for copolymerizing a conjugated diene and an aromatic vinyl compound in the presence of the catalyst composition according to claim 1. Description: 7. A copolymer obtainable by copolymerizing a conjugated diene and an aromatic vinyl compound in the presence of the catalyst composition according to claim 1. Description: 8. The copolymer according to claim 7, wherein the content of the cis 1,4-structure in the microstructure is 80 mol% or more, and the molecular weight distribution Mw / Mn is 2.00 or less. 9. A random copolymer of a conjugated diene and an aromatic vinyl compound, wherein the cis 1,4-
A copolymer having a structure content of 80 mol% or more, a molecular weight of 10,000 or more, and a molecular weight distribution Mw / Mn of 2.50 or less.