JPH05295021A - Method for polymerizing olefin - Google Patents

Abstract

PURPOSE:To efficiently carry out the polymerization of an olefin with high activity and provide a polyolefin having a high molecular weight by bringing the olefin into contact with a catalyst composed of a specific transition metal compound, a a specified boron compound and a specific alumoxane compound and using a decreased amount of the resultant organoaluminum component. CONSTITUTION:An olefin is brought into contact with a catalyst composed of (A) a group IVB transition metal compound having a (substituted) cyclopentadiene ring as a ligand (e.g. biscyclopentadienylzirconium dichloride), (B) an organometallic component composed of an alumoxane compound and (C) the third component composed of a boron compound of the formula BRnX3-n [R is a 1-12C hydrocarbon residue; X is a halogen, 1-12C alkoxy, allyloxy or H; (n) is 1-3], e.g. trimethylboron to carry out the polymerization of the olefin. Furthermore, the atomic ratio of the Al in the component (B) to the metal in the component (A) is preferably 5-500 and the atomic ratio of the boron in the component (C) to the metal in the component (A) is preferably 1-50.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION The present invention relates to a process for polymerizing olefins. Specifically, the present invention relates to an improved process for polymerizing olefins by the use of reduced organoaluminum components due to the combination of novel catalyst components.

[0002]

2. Description of the Related Art Conventionally, it has been known that an olefin can be polymerized with high activity in a catalyst system comprising a group IVB transition metal compound and a methylalumoxane which is an oligomeric organoaluminum compound (JP-A-58). -193
09, JP-A-60-35007, etc.). Such a catalyst system has good copolymerizability, the stereoregularity can be freely controlled by a ligand, and the produced polymer has a narrow molecular weight distribution. When the amount of the organoaluminum compound used in (1) is small, the activity is drastically reduced. Therefore, the amount of the organoaluminum compound used as the activator is generally very large and the cost is high.

Therefore, various proposals have been made for the purpose of reducing the amount of activator used. For example, (a) a method of combining a Group IVB transition metal compound with a tetravalent boron compound anion, specifically, boron such as tri-n-butylammonium tetraphenylborate or triphenylcarbenium tetrakis (pentafluorotetraphenyl) borate. A method of combining a salt and a neutral metallocene compound (Japanese Patent Laid-Open No. 1-502036, Japanese Patent Laid-Open No. 3-2).
No. 07703, etc.), and a method of combining a (b) Group IVB transition metal compound and a trivalent boron compound, specifically tris (pentafluorophenyl) borane (J. Am. Chem. Soc. (1991)). ), 11
3, 3623) and the like.

In such a method, the amount of the organoaluminum compound as the activator used may be small, and
Since the amount of the boron compound used is generally small, the cost of the activator can be reduced, but the activity per transition metal of the catalyst is reduced, so that the total cost of the catalyst is increased, in particular of α-olefin such as propylene. There is a problem that the polymerization activity is greatly reduced.

Further, a neutral metallocene compound and aluminum alkyl (preferably trialkylaluminum)
And a Lewis acid (preferably tris (pentafluorophenyl) borane) in combination (JP-A-3-179)
No. 005) has been proposed, but it seems that the activity per transition metal is still insufficient in practical use.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a method for polymerizing olefins which, by using a novel combination of catalyst components, reduces the amount of activator used and gives polyolefins of high activity and good quality. The purpose is.

[0007]

[Means for Solving the Problems]

[Summary of the Invention] <Outline> The method for polymerizing an olefin according to the present invention is characterized in that an olefin is brought into contact with a catalyst composed of the following components (A), (B) and (C) for polymerization. Is.

Component (A): Group IVB transition metal compound having a substituted or unsubstituted cyclopentadiene ring as a ligand, Component (B): alumoxane compound, Component (C): with general formula BR _n X _3-n Boron compound represented (wherein R is a hydrocarbon residue having 1 to 12 carbon atoms,
X is halogen, an alkoxy or aryloxy group having 1 to 12 carbon atoms, or hydrogen. In addition, n is an integer of 1 to 3. ).

<Effect> According to the present invention, it is possible to produce a polyolefin having a high activity and a large molecular weight by using a novel combination of the catalyst components and using a reduced organoaluminum component.

[Detailed Description of the Invention] [Catalyst] The catalyst of the present invention comprises components (A), (B) and (C). Here, "consisting of" means that the components are those listed (that is, the component (A),
It does not mean that only (B) and (C)), and does not exclude the coexistence of purposefully other components.

<Component (A)> The component (A) has a substituted or unsubstituted cyclopentadiene ring as a ligand.
It is a Group IVB transition metal compound. This compound is specifically represented by the following general formula. ^{_{(R 1 h -Cp) j (}} R 2 i -Cp) k MQ 1 r Q 2 s

Here, Cp represents a cyclopentadienyl group, and R ¹ and R ² each represent a hydrocarbon group having 1 to 12 carbon atoms or a silicon group having a hydrocarbon residue having 1 to 12 carbon atoms. .. h and i independently represent an integer of 0 to 5. Therefore, when h or i is 0, it represents an unsubstituted cyclopentadienyl group, and when h or i is a natural number, it represents a substituted cyclopentadienyl group. R ¹ and R ² are
In either case, when there are a plurality of them (especially when there are two), they may be condensed with each other to form a condensed ring with a cyclopentadienyl group ring. That is, for example, R ¹ or R ² may be ^one in which a double bond of Cp is shared to form a condensed 6-membered ring, that is, an indenyl group or a fluorenyl group. At the same time, R ¹ _h -Cp and R ² _i -Cp
And may be bonded to each other through a bridging group such as an alkylene having about 1 to 4 carbon atoms or a silicon-containing divalent hydrocarbon group to form a crosslinked cyclopentadiene ligand. k represents an integer of 0, 1, 2 and j represents an integer of 1, 2. M is a transition metal selected from Group IVB Ti, Zr and Hf. Q ¹ and Q ² are independently a hydrogen atom,
Hydrocarbon residue having 1 to 12 carbon atoms, silicon-substituted hydrocarbon residue having hydrocarbon residue having 1 to 12 carbon atoms, halogen atom, alkoxy group having hydrocarbon residue having 1 to 20 carbon atoms, phenoxy group , An amide group having a hydrocarbon residue having 1 to 20 carbon atoms. Here, Q ¹ and R ¹ -Cp may be bonded to each other. Also, Q ¹ and Q ² may be bonded to each other. r and s each independently represent an integer of 0 to 3, and j + k + r + s = 4.

Non-limiting specific examples of such a group IVB transition metal compound (component (A)) include (1) biscyclopentadienyl zirconium dichloride, (2) biscyclopentadienyl zirconium dimethyl, (3) ) Biscyclopentadienylzirconium diisobutyl,
(4) Biscyclopentadienyl zirconium dihydride, (5) Biscyclopentadienyl zirconium chloride hydride, (6) Biscyclopentadienyl zirconium diphenyl, (7) Biscyclopentadienyl zirconium methoxide, (8) Bis (methylcyclopentadienyl) zirconium dichloride,
(9) Bis (ethylcyclopentadienyl) zirconium dichloride, (10) Bis (n-butylcyclopentadienyl) zirconium dichloride,

(11) Bis (t-butylcyclopentadienyl) zirconium dichloride, (12) bis (cyclohexylcyclopentadienyl) zirconium dichloride, (13) bis (trimethylsilylcyclopentadienyl) zirconium dichloride, (14) Bis (phenylcyclopentadienyl) zirconium dichloride,
(15) Bis (dimethylcyclopentadienyl) zirconium dichloride, (16) Bis (trimethylcyclopentadienyl) zirconium dichloride, (17) Bis (tetramethylcyclopentadienyl) zirconium dichloride, (18) Bis (pentamethyl Cyclopentadienyl) zirconium dichloride, (19) bis (indenyl) zirconium dichloride, (20) (cyclopentadienyl) (pentamethylcyclopentadienyl)
Zirconium dichloride,

(21) (cyclopentadienyl) (methylcyclopentadienyl) zirconium dichloride,
(22) Methylenebis (indenyl) zirconium dichloride, (23) Isopropenylbis (indenyl) zirconium dichloride (24) Ethylenebis (indenyl) zirconium dichloride, (25) Ethylenebis (4,5,6,7-tetrahydroindenyl) Zirconium dichloride, (26)
Ethylenebis (2-methylindenyl) zirconium dichloride, (27) ethylenebis (3-methylindenyl) zirconium dichloride, (28) ethylenebis (4-methylindenyl) zirconium dichloride,
(29) Ethylenebis (2,3-dimethylindenyl) zirconium dichloride, (30) Ethylenebis (4,7
-Dimethylindenyl) zirconium dichloride,

(31) Dimethylsilylenebis (indenyl) zirconium dichloride, (32) Dimethylsilylenebis (4,5,6,7-tetrahydroindenyl) zirconium dichloride, (33) Dimethylsilylenebis (2-methylindenyl) Zirconium dichloride,
(34) Dimethylsilylenebis (3-methylindenyl)
Zirconium dichloride, (35) dimethylsilylenebis (tetramethylcyclopentadienyl) zirconium dichloride, (36) dimethylsilylenebis (methylcyclopentadienyl) zirconium dichloride, (3
7) Dimethylsilylenebis (dimethylcyclopentadienyl) zirconium dichloride, (38) Dimethylsilylenebis (t-butylcyclopentadienyl) zirconium dichloride, (39) Dimethylsilylenebis (t-
Butyl, methylcyclopentadienyl) zirconium dichloride, (40) dimethylsilylenebis (trimethylsilylcyclopentadienyl) zirconium dichloride,

(41) Diphenylsilylenebis (indenyl) zirconium dichloride, (42) Diphenylsilylenebis (4,5,6,7-tetrahydroindenyl)
Zirconium dichloride, (43) isopropylidene (cyclopentadienyl) (tetramethylcyclopentadienyl) zirconium dichloride, (44) isopropylidene (cyclopentadienyl) (dimethylcyclopentadienyl) zirconium dichloride, (45) isopropylidene Ridene (cyclopentadienyl) (indenyl)
Zirconium dichloride, (46) isopropylidene (cyclopentadienyl) (9-fluorenyl) zirconium dichloride, (47) isopropylidene (methylcyclopentadienyl) (9-fluorenyl) zirconium dichloride, (48) diphenylmethylene (cyclopentadiene) Dienyl) (9-fluorenyl) zirconium dichloride, (49) Dichlorohexylidene (cyclopentadienyl) (9-fluorenyl) zirconium dichloride, (50) Dimethylsilylene (cyclopentadienyl) (9-fluorenyl) zirconium dichloride ,

(51) Diphenylsilylene (cyclopentadienyl) (9-fluorene) zirconium dichloride, (52) cyclopentadienyl zirconium trichloride, (53) pentamethylcyclopentadienyl zirconium trichloride, (54) cyclo Pentadienyl zirconium trimethyl, (55) Cyclopentadienyl zirconium tribenzyl, (56) Cyclopentadienyl zirconium triethoxide, (57) Cyclopentadienyl zirconium triphenoxide, (58) Cyclopentadienyl zirconium methyl Dichloride,
(59) cyclopentadienyl zirconium tris (trimethylsilylmethyl), (60) cyclopentadienyl zirconium tris (dimethylamide),

(61) Indenyl zirconium trichloride, (62) methylene (tetramethylcyclopentadienyl) (t-methylamido) zirconium dichloride, (63) ethylene (tetramethylcyclopentadienyl) (t-butylamido) zirconium Dichloride,
(64) Ethylene (tetramethylcyclopentadienyl)
(Methylamido) zirconium dichloride, (65) dimethylsilylene (tetramethylcyclopentadienyl)
(T-Butylamido) zirconium dichloride, (6
6) Tetramethyldisilyne (tetramethylcyclopentadienyl) (t-butylamido) zirconium dichloride, (67) Dimethylsilylene (tetramethylcyclopentadienyl) (phenylamido) zirconium dichloride, (68) Dimethylsilylene (indenyl) (T
-Butylamido) zirconium dichloride, (69) dimethylsilylene (9-fluorenyl) (t-butylamido) zirconium dichloride, and (70) compounds in which zirconium in these zirconium compounds is replaced with titanium or hafnium. Among such compounds, preferred are those having a structure in which R ¹ h-Cp and the other ligand are bridged by an alkylene or Si group having 1 to 4 carbon atoms. More preferred are those in which Q ¹ is Cl or a methyl group. This component may be used alone or in combination. Further, it can be used by being carried on an inert carrier.

<Component (B)> The component (B) is an alumoxane compound. The alumoxane compound is an oligomeric oxygen-containing organoaluminum compound, which includes a cyclic compound and a linear compound, and is generally a mixture of both. The cyclic one can be represented by the following general formula (a).

[0021]

[Chemical 1]

Further, the straight-chain type has the following general formula (b)
Can be represented by.

[0023]

[Chemical 2]

Where R ³ , R ⁴ , R ⁵ and R ⁶ are
Independently, a hydrocarbon residue having 1 to 5 carbon atoms is shown, and x is 1 to
The number of 50 is shown. Various methods for producing such alumoxane are known. For example, an organoaluminum compound such as a method of contacting water with an organoaluminum compound in an organic solvent, a method of contacting an organoaluminum compound with a salt containing water of crystallization, a method of contacting an organoaluminum compound with a hydrous inorganic oxide, and the like. The method by hydrolysis of is generally used.

In the present invention, for example, any alumoxane compound produced by the above-mentioned method can be used as the component (B). Among them, preferred are trimethylaluminum, triethylaluminum, triisobutylaluminum and dimethylaluminum. This is due to hydrolysis of organoaluminum compounds such as chloride, diethylaluminum chloride and diisobutylaluminum chloride. More preferred is methylalumoxane having a number average degree of polymerization (x in the above general formula) of 4 to 40. Methylalumoxane can be used alone or as a mixture with other organoaluminum compounds.

<Component (C)> The component (C) has the general formula BR
It is a boron compound represented by _n X _3-n . Where R
Is a hydrocarbon residue having 1 to 12 carbon atoms, preferably 2 to 8, X is halogen, and 1 to 12 carbon atoms, preferably 2
An alkoxy or aryloxy group of 8, or hydrogen. In addition, n is an integer of 1 to 3. Non-limiting specific examples of such a boron compound include (1) trimethyl boron, (2) triethyl boron, (3) tripropyl boron, (4) tributyl boron, (5) tripentyl boron and (6) tri Hexyl boron, (7) trioctyl boron, (8) tridecyl boron, (9) tricyclohexyl boron, (10) triphenyl boron,

(11) Tritolylboron, (12) Trixylylboron, (13) Tri (fluorophenyl) boron,
(14) Tris (difluorophenyl) boron, (15) Tris (pentafluorophenyl) boron, (16) Tri (chlorophenyl) boron, (17) Tris (di-trifluoromethylphenyl) boron, (18) Dimethylethylboron , (19) diethylbutylboron, (20) diethylphenylboron,

(21) Diphenylmethylboron, (22) Diphenylethylboron, (23) Methylethylphenylboron, (24) Dimethylchloroboron, (25) Diethylfluoroboron, (26) Diethylchloroboron, (27) Diethyl Bromoboron, (28) dibutylchloroboron,
(29) diphenylchloroboron, (30) di (pentafluorophenyl) chloroboron,

(31) Ethylphenylchloroboron, (3
2) Diethylmethoxyboron, (33) Diethylethoxyboron, (34) Diethylpropoxyboron, (35) Diethylbutoxyboron, (36) Diethylphenoxyboron, (37) Dibutylethoxyboron, (38) Dibutylbutoxyboron, (39 ) Dibutyl 2-ethylhexoxyboron, (40) diphenylethoxyboron,

(41) Diphenylphenoxyboron, (4
2) Diethylborohydride, (43) Dibutylborohydride, (44) Diphenylborohydride, (45) Ethyldichloroboron, (46) Butyldichloroboron, (47) Phenyldichloroboron, (48) Phenyldifluoroboron , (49) phenyldibromoboron, (50) ethyldimethoxyboron,

(51) Ethyldiethoxyboron, (52) Ethyldibutoxyboron, (53) Ethyldiphenoxyboron, (54) Butyldiethoxyboron, (55) Butyldiphenoxyboron, (56) Phenyldimethoxyboron,
Examples thereof include (57) phenyldiethoxyboron, (58) phenyldiphenoxyboron, (59) ethylborohydride, (60) butylborohydride, (61) phenylborohydride and the like.

Among these, preferred are alkyl or allylboron compounds with n = 2 and 3, and more preferred are trialkyl and triphenylborane with n = 3.

<Amount of Components> The amount ratio of the catalyst components (A) to (C) is not limited within the range where the effect of the present invention is exerted, but is preferably in the component (B) for the purpose of the present invention. The atomic ratio of Al to M in the component (A) is 1 to 2000, and more preferably 5 to 500. The atomic ratio of B (boron) in the component (C) to M in the component (A) is preferably 0.
2 to 200, more preferably 1 to 50. The components (A) to (C) may be directly introduced into the polymerization tank separately, but any two or three components may be contacted in advance and used. When pre-contacting, the component (A)
It is preferable to use after contacting with the component (C).

<Use of Catalyst / Polymerization> The monomer to be polymerized using the catalyst of the present invention is an α-olefin, diolefin or cyclic olefin having 2 to 12 carbon atoms. Specifically, ethylene, propylene, 1-butene, 1-pentene, 3-methylbutene-1,1-hexene, 4-methylpentene-1,1-octene, 1-decene, 1,3
-Butadiene, 1,4-pentadiene, 1,5-hexadiene, 7-methyl 1,7 octadiene, cyclopentene, cycloheptene and the like can be exemplified. These can be polymerized alone, but two or more kinds can also be used.

As the polymerization method, a liquid phase, a gas phase, a high pressure fluidized phase, or any other known method can be adopted. In addition, these methods may be adopted individually or in a series. When a solvent is used, aromatic hydrocarbon solvents such as benzene, toluene, xylene, n-pentane, n-hexane, n-heptane,
Aliphatic hydrocarbon solvents such as n-paraffin, alicyclic hydrocarbon solvents such as cyclohexane and methylcyclopentane, and monomers themselves such as propylene and 1-hexene can be used as the solvent.

The polymerization temperature is -20 ° C to 260 ° C, preferably 40 to 220 ° C, and the polymerization pressure is atmospheric pressure to 200 ° C.
It is appropriately selected within the range of 0 kg / cm ² G. The polymerization time varies depending on the process, but is appropriately selected within the range of 10 seconds to 12 hours. A molecular weight modifier can be used in the polymerization. Typically, hydrogen gas can reduce the molecular weight of the produced polymer.

[0037]

EXAMPLE 1 A 100 ml dry glass flask was thoroughly replaced with N ₂ and 10 ml of toluene, 0.03 mmol of bispentamethylcyclopentadienylzirconium dichloride and 0.03 mmol of triphenylboron were introduced. The mixture was stirred at room temperature for 30 minutes. 300 ml of purified toluene was introduced into a 1-liter autoclave with a stirring blade that had been sufficiently dried and substituted with ethylene, and then 0.90 mmol of methylalumoxane (in terms of Al atom) and the whole amount of the above catalyst preparation solution were introduced into a polymerization tank. .. The ethylene pressure in the polymerization tank was maintained at 0.2 kg / cm ² G, and polymerization was carried out at 40 ° C. for 1 hour. As a result, 14.
9 g of polyethylene was obtained. The Mn was 1.58 × 10 ⁵ , the Mw was 3.56 × 10 ⁵ , and the molecular weight distribution Q value (Mw / Mn) was 2.25.

Comparative Example-1 Polymerization was carried out in the same manner as in Example-1 except that triphenylboron (component (C)) was not used in Example-1. As a result, 1.1 g of polyethylene was obtained. The Mn was 2.16 × 10 ⁴ , the Mw was 7.39 × 10 ⁴ , and the Q value was 3.42.

Example-2 In Example-1, except that 0.023 mmol of bispentamethylcyclopentadienylzirconium diphenyl was used in place of 0.03 mmol of bispentamethylcyclopentadienylzirconium chloride in Example-1. −
Catalyst preparation and polymerization were carried out in the same manner as in 1. as a result,
16.8 g of polyethylene was obtained. Its molecular weight is M
n is 2.16 × 10 ⁵ , Mw is 4.78 × 10 ⁵ , and Q
The value was 2.21.

Comparative Example-2 Polymerization was carried out in the same manner as in Example-2 except that triphenylboron (component (C)) was not used in Example-2. As a result, 6.9 g of polyethylene was obtained. The Mn was 1.62 × 10 ⁵ , the Mw was 4.00 × 10 ⁵ , and the Q value was 2.47.

Example 3 In Example 1, 0.027 mmol of bispentamethylcyclopentadienylzirconium dimethyl was used in place of 0.03 mmol of bispentamethylcyclopentadienylzirconium dichloride, and 0.03 mol of triphenylboron was used. Instead, triethylboron 0.135mm
A catalyst was prepared and polymerized in the same manner as in Example 1 except that ol was used. As a result, 13.7 g of polyethylene was obtained. Its molecular weight is Mn 8.76 × 1.
0 ⁴ , Mw was 1.95 × 10 ⁵ , and Q value was 2.22.

Comparative Example-3 In Example-3, polymerization was carried out by using 1.0 mmol of triethylaluminum instead of 0.90 mmol of methylalumoxane (calculated as Al atom) (component (B)).
No polymer was obtained.

Example 4 A 100 ml dry glass flask was thoroughly dried with N ₂ and 20 ml of toluene, 0.074 mmol of pentamethylcyclopentadienyl zirconium chloride and 0.2 were added.
2 mmol of triphenylboron was introduced, and the mixture was stirred at room temperature for 30 minutes. 300 ml of purified toluene was introduced into the polymerization tank which had been sufficiently dried and substituted with ethylene, and then 3.0 mmol of methylalumoxane was introduced in terms of Al atom, and 1 / 8.1 amount of the above catalyst preparation liquid (0.006 mmol Zr equivalent) )
Was introduced into the polymerization tank. The ethylene pressure in the polymerization tank is 0.2 kg /
It was kept at cm ² G and polymerized at 40 ° C. for 1 hour. as a result,
10.5 g of polyethylene was obtained. Its molecular weight is M
r is 3.28 × 10 ⁴ , Mw is 8.43 × 10 ⁴ , and Q
The value was 2.57.

Comparative Example-4 Polymerization was carried out in the same manner as in Example-4 except that triphenylboron (component (C)) was not used in Example-4. As a result, 5.9 g of polyethylene was obtained. The molecular weight was 1.23 × 10 ^{4 for} Mn, 5.75 × 10 ⁴ for Mw, and the Q value was 4.67.

Example 5 A 100 ml dry glass flask was thoroughly dried with N ₂ and 10 ml of toluene and ethylene bis (4,5,6,7) were added.
-Tetrahydroindenyl) zirconium dimethyl 0.
03 mmol and triphenylboron 0.09 mmol were introduced, and the mixture was stirred at room temperature for 30 minutes. 10 ml of purified toluene was introduced into a pressure-resistant 1 liter autoclave that had been sufficiently dried in advance and replaced with propylene, and then methylalumoxane was added to A
3.0 mmol of 1 atom conversion was introduced, and the whole amount of the catalyst preparation solution was introduced into the polymerization tank.

Then, 400 ml of liquefied propylene was introduced and stirred at 15 ° C. for 1 hour. After the completion of the polymerization, the monomer was purged and the product was dried under reduced pressure to obtain a polymer. As a result, 33.2 g of polypropylene was obtained. The product was isotactic polypropylene having a mm of 0.95 by NMR. Its molecular weight is Mn = 5.
88 × 10 ⁴ , Mw 1.42 × 10 ⁵ , Q value 2.
It was 42.

Comparative Example-5 Polymerization was carried out in the same manner as in Example-5 except that triphenylboron (component (C)) was not used in Example-5. As a result, 26.1 g of polypropylene was obtained. The product was isotactic polypropylene with a mm of 0.94 by NMR. Its molecular weight is M
n is 3.43 × 10 ⁴ , Mw is 8.08 × 10 ⁴ , and Q
The value was 2.36.

[0048]

[Table 1]

Table 1 shows the results obtained in the above experimental examples.

[0050]

EFFECT OF THE INVENTION According to the present invention, it is possible to produce a polyolefin having a high activity and a large molecular weight by using a novel combination of catalyst components in the use of a reduced organoaluminum component. As described above in.

[Brief description of drawings]

FIG. 1 is intended to assist in understanding the technical content of the present invention regarding a Ziegler catalyst.

Claims (1)

[Claims] 1. A process for polymerizing an olefin, which comprises contacting an olefin with a catalyst comprising the following components (A), (B) and (C) to polymerize the catalyst. Component (A): Group IVB transition metal compound having a substituted or unsubstituted cyclopentadiene ring as a ligand, Component (B): alumoxane compound, Component (C): boron represented by the general formula BR _n X _3-n Compound (where R is a hydrocarbon residue having 1 to 12 carbon atoms,
X is halogen, an alkoxy or aryloxy group having 1 to 12 carbon atoms, or hydrogen. In addition, n is an integer of 1 to 3. ).