JPS59129204A - Production of polyolefin - Google Patents

Abstract

PURPOSE:To produce a highly stereoregular polyolefin in high activity, by (co) polymerizing an alpha-olefin in the presence of a catalyst comprising a specified solid catalyst component, an organometallic compound, and a silane compound. CONSTITUTION:A catalyst is prepared by combining an organometallic compound (e.g., triethylaluminum) with a silane compound of formula I (wherein R<1-3> are each a hydrocarbon residue, alkoxy, H, or a halogen, R<4> is a 1-24C hydrocarbon residue, and n is in the range of 1<=n<=30), and a solid catalyst component prepared by infiltrating a Ti compound (e.g., TiCl4) into a solid substance obtained by copulverizing a magnesium halide (e.g., MgCl2), a silane compound of formula I , and a compound of formula II (wherein R<5> is R<4>) in the presence (or absence) of an inert solvent. An alpha-olefin is (co)polymerized at 20-300 deg.C and a pressure of atmosphere -70kg/cm<2>G in the presence of the above catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for polymerizing or copolymerizing α-olefins with high activity and good stereoregularity using a new catalyst.

Catalysts consisting of titanium halides and organoaluminum compounds have been known as highly stereoregular polymerization catalysts for α-olefins. However, in polymerization using this catalyst system, although a highly stereoregular polymer is obtained, the catalyst activity is low, so it is necessary to remove catalyst residues from the produced polymer.

In recent years, many proposals have been made to improve the activity of catalysts. According to these proposals, it has been shown that a highly active catalyst can be obtained when a catalyst component in which titanium tetrachloride is supported on an inorganic solid carrier such as Mg012 is used.

However, in the production of polyolefins, it is preferable that the catalyst activity be as high as possible, and catalysts with even higher activity have been desired. It is also important that the amount of active moieties produced in the polymer is as small as possible.

As a result of intensive research on these points, the present inventors found that
Here, a new catalyst was discovered. That is,
The present invention relates to a method for producing polyolefins with extremely high activity and high stereoregularity using a novel catalyst. By using the catalyst of the present invention, the monomer partial pressure during polymerization is low and the polymerization time is shortened. The amount of catalyst residue in the resulting polymer is extremely small, so the catalyst removal step can be omitted in the polyolefin manufacturing process, and the amount of atactic moieties produced in the resulting polymer is also extremely small. is obtained.

The present invention will be explained in detail below.

The present invention is CI) (1) Magnesium halide, (2
) General formula 1 R3(-8i-09R4 (here, R1, R2, and R3 represent a hydrocarbon residue having 21 to 24 carbon atoms, an alkoxy group, hydrogen, or a halogen atom, and R4 represents a hydrogen atom having 1 to 24 carbon atoms. (where R5 is a hydrocarbon residue having 1 to 24 carbon atoms), and (3) a compound represented by the general formula P(OR5)3 (where R5 is a hydrocarbon residue having 1 to 24 carbon atoms). 1 [■] Organometallic Compound, Oyobi(]fD (5) General formula R3+St -0-)-R'2 (Here, R11, R2, R3 are hydrocarbon residues having 1 to 24 carbon atoms, alkoxy groups, hydrogen or halogen atoms? , R4 represents a hydrocarbon residue having 1 to 24 carbon atoms. n is 1
≦n≦30. This invention relates to a method for producing polyolefins with extremely high activity and stereoregularity by polymerizing or copolymerizing α-olefins using a catalyst containing a combination of compounds represented by the following formulas.

In the present invention, (1)...magnesium rogenide, (
2) A compound represented by the general formula R3 (-8i-O+R') and (3) a compound represented by the general formula (0 2 formula P(OR5)3) are brought into contact with each other to obtain the solid substance of the present invention. There is no limit, and the temperature is between 20°C and 40°C in the presence or absence of an inert solvent.
Under heating at 0°C, preferably 50°C to 300°C, usually,
A method of causing a reaction by contacting for 5 minutes to 20 hours,
The reaction may be carried out by co-pulverization, or by a suitable combination of these methods.

However, there are no particular restrictions on the reaction order of components (1) to (3); six components may be reacted at the same time, or two components may be reacted, and then the remaining one component may be reacted. Good too.

The inert solvent is not particularly limited, and hydrocarbon compounds and/or derivatives thereof that are capable of inactivating Ziegler-type catalysts can generally be used. Specific examples of these include extremely aliphatic saturated hydrocarbons such as propane, butane, pentane, hexane, heptano, octane, benzene, toluene, xylene, and cyclohexane, aromatic hydrocarbons, alicyclic hydrocarbons, and ethanol, Examples include alcohols, ethers, and esters such as diethyl ether, tetrahydrofuran, ethyl acetate, and ethyl benzoate.

It is desirable that the co-pulverization treatment is carried out using a device such as a ball mill, a vibration mill, a rod mill, or an impact mill, usually at a temperature of 0°C to 200°C, preferably 20°C to 100°C, for 05 to 60 hours.

In the present invention, a method of obtaining a solid carrier by co-pulverizing components (1) to (3) is particularly preferably employed.

In the present invention, the ratio of component (1) magnesium halide to component 1 (2) compound represented by the general formula R3+5i-0+nR' is 1:1 in molar ratio of component (2). ,
001 to 1o, preferably 0.01 to 1o. Component (3) The compound represented by the general formula P(OR5)3 is used in a molar ratio of component (1):component (3) of 1:0.
001-10. Preferably, the ratio is 1:0.01 to 1. A titanium compound is supported on the solid carrier thus obtained to obtain the solid catalyst component [I].

A known method can be used to support the titanium compound on the carrier. For example, this can be carried out by contacting the solid support with an excess of titanium compound under heat, in the presence or absence of a solvent, preferably by
1. Both in the presence of a solvent such as 2-dichloroethane, 5
This is conveniently carried out by heating to 0°C to 300°C, preferably 80°C to 150°C. The reaction time is not particularly limited, but is usually 5 minutes or more, and long-term contact may be allowed, although it is not necessary. For example, the treatment time can be from 5 minutes to 10 hours, preferably from 1 to 4 hours. Of course, this treatment should be carried out under an inert gas atmosphere free of oxygen and moisture.

The means for removing unreacted titanium compounds after completion of the reaction is not particularly limited, and a solid powder can be obtained by washing the Ziegler catalyst several times with an inert solvent and evaporating the washings under reduced pressure conditions. . Another method is to co-pulverize the solid support and the required amount of the titanium compound.

In the present invention, co-grinding is usually carried out at a temperature of 0°C to 200°C, preferably 20°C to 100°C for 0.5 to 30 hours to produce the catalyst component of the present invention. The cultivation should be carried out in an inert gas atmosphere and excessive moisture should be avoided as much as possible.

The magnesium halide used in the present invention is substantially anhydrous and includes magnesium fluoride, magnesium chloride, magnesium bromide, magnesium iodide, and mixtures thereof, with magnesium chloride being particularly preferred.

1 General formula used in the present invention R3+5i-O+R
'2 (Here, R', R2, and R3 represent a hydrocarbon group having 1 to 24 carbon atoms, preferably 1 to 18 carbon atoms, an alkoxy group, an aqueous group, or a halogen atom, and R4 represents a carbon atom having 1 to 24 carbon atoms, or 1 to 18 hydrocarbon residues, where n is 1≦n≦50
It is. ), monomethyltri/stoxysilane, monomethyltriethoxysilane,
Monomethyltri-n-butoxysilane, monomethyltri-B
eQ-butoxysilane, monomethyltriynepropoxysilane, monomethyltripentoxysilane, monomethyltrioctoxysilane, monomethyltristearoxysilane, monomethyltriphenoxysilane, dimethyldimethoxysilane, dimethyljethoxysilane, dimethyldiinobroboxysilane, dimethyldiphenoxysilane,
Trimethylmonomethoxysilane, trimethylmonoethoxysilane, trimethylmonoisopropoxysilane, trimethylmonophenoxysilane, monomethyldimethoxymonochlorosilane, monomethylmonoethoxydichlorosilane, monomethyljethoxymonochlorosilane, monomethyljethoxymonobromosilane, monomethyldiphenoxy monochrome Silane, dimethylmonoethoxymonochlorosilane, monoethyltrimethoxysilane, monoethyltriethoxysilane, monoethyltriisopropoxysilane, monoethyltriphenoxysilane, diethyldimethoxysilane, diethyljethoxysilane, diethyldiphenoxysilane, triethylmono Ethoxysilane, triethylmonoethoxysilane, triethylmonophenoxysilane, monoethyldimethoxymonochlorosilane, monoethyljethoxymonochlorosilane, monoethyldiphenoxymonochlorosilane, mono n-butyltrimethoxysilane, mono n-butyltrimethoxysilane, mono n-
Butyltriethoxysilane, mono5ee-butyltriethoxysilane, monophenyltrimethoxysilane, monophenyltriethoxysilane, monophenyltriphenoxysilane, diphenyljethoxysilane, diphenylmonoethoxymonochlorosilane, monomethoxytrichlorosilane, monoethoxy Trichlorosilane, monoisopropoxytrichlorosilane, mono n-butoxytrichlorosilane, monopentoxytrichlorosilane, monooctoxytrichlorosilane, monostearoxytrichlorosilane, monophenokiditrichlorosilane, mono p-methylphenokiditrichlorosilane, dimethoxydichlorosilane , dimethoxydichlorosilane, diisopropoxydichlorosilane, moro-butoxydichlorosilane, dioctoxydichlorosilane, trimethoxymonochlorosilane, triethoxymonochlorosilane, triinpropoxymonochlorosilane, ) n-butoxymonochlorosilane, tri5eC- Butoxymonochlorosilane, tetraethoxysilane, tetranepropoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyldimethoxymonochlorosilane, vinyljethoxymonochlorosilane, vinylmethoxydichlorosilane, vinylethoxydichlorosilane, allyltrimethoxysilane,
Allyltriethoxysilane, allyldimethoxymonochlorosilane, allyljethoxymonochlorosilane, allylmethoxydichlorosilane, allylethoxydichlorosilane, vinyltriphenoxysilane, vinylethoxydiphenoxy7rane, allyltriphenoxysilane, allylethoxydiphenoxysilane , and the above compound are condensed, and the &'t repeating unit is represented by 1 +5i-0+ , and a step-shaped polysilane atmosphere 2 xane can be formed. It can also be used as a mixture of these.

Among these compounds, as component (2), it is preferable that at least one substituent has an olefinic hydrocarbon group, such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriphenoxysilane, and plyyl. Particularly preferred are trimethoxysilane, allyltriethoxysilane, and allyltriphenoxysilane.

Further, as component (5), at least one substituent preferably has an aromatic hydrocarbon group, and monophenyltrimethoxysilane and monophenyltriethoxysilane are particularly preferable.

General formula P(OR5)3 used in the present invention (
Here, R5 represents a hydrocarbon residue having 1 to 24 carbon atoms, preferably 1 to 18 carbon atoms, and R5 may be the same or different. ) Examples include trimethyl phosphite, triethyl phosphite, tripropyl phosphite, triinpropyl phosphite, tri-n-butyl phosphite, triisobutyl phosphite, trivinyl phosphite, triallylphosphite, tri- Isobutyl phosphite, triphenyl phosphite, tricyclohexyl phosphite, tris(tert-amylphenylsynphosphite, tris(nonyl-phenyl) phosphite, toIJ(3,5-diethylphenyl)
Phosphite, Tri 0-) Ruyl phosphite, Tri 1
- Naphthyl phosphite, tris(2-ethylhexyl) phosphite, diphenyl-ethyl phosphite, diphenyl-ingropylphosphite, diphenyl-imbutyl phosphite, diphenyl-nonylphenyl phosphite, diphenyl-indecyl phosphite, phenyl -diisooctyl phosphite, phenyl-diindecylbosphite, phenyl-diisobutyl phosphite and the like.

As the titanium compound used in the present invention, tetravalent titanium compounds and trivalent titanium compounds are suitable. Specifically, the tetravalent titanium compound has the general formula Ti(OR)nX
4-n (where R represents an alkyl group, aryl group, or aralkyl group having 1 to 20 carbon atoms, and X represents a halogen atom. Titanium tetrachloride, titanium tetrabromide, titanium tetraiodide,
Monomethoxytrichlorotitanium, dimethoxydichlorotitanium, trimethoxymonochlorotitanium, tetramethoxytitanium, monoethoxytrichlorotitanium, jetoxydichlorotitanium, triethoxymonochlorotitanium, tetraethoxytitanium, monoisopropoxytri, chlorotitanium, diisopropoxydichlorotitanium , triisopropoxymonochlorotitanium, tetralinepropoxytitanium,
Monobutoxytrichlorotitanium, dibutoxydichlorotitanium, monopentoxytrichlorotitanium, monophenoxytrichlorotitanium, diphenoxydichlorotitanium,
Triphenoxymonochlorotitanium, tetraphenoxytitanium, etc. can be used. Trivalent titanium compounds are obtained by reducing titanium chlorides such as titanium tetrachloride and titanium tetrabromide with hydrogen, aluminum, titanium, or organometallic compounds of metals from groups 1 to 2 of the periodic table. Examples include titanium trihalide. Also, the general formula Ti(
OR)mX4-m (where R represents an alkyl group, aryl group, or aralkyl group having 1 to 20 carbon atoms, and
・Indicates a rogen atom. m is 0<m<4. ) is the tetravalent alkoxy titanium halide shown in the first part of the periodic table.
3 obtained by reduction with an organic compound of ~■ group metal
A titanium compound of high valence is produced.

In the present invention, the amount of the titanium compound used is not particularly limited, but it is usually adjusted so that the amount of the titanium compound contained in the solid product is 0.5 to 20% by weight, preferably 1 to 10% by weight. is preferable.

As the organometallic compound used in the present invention, organometallic compounds belonging to Groups 1 to 1 of the periodic table, which are known as components of Ziegler's catalyst, can be used, but specific aluminum compounds and organozinc compounds are particularly preferred. Specific examples include general formulas R3Al, R2AIX, RAIX2,
R2Al OR, RAI (0R)X and R3A12
Organoaluminum compound of X3 (wherein R has 1 to 1 carbon atoms)
2o alkyl group or aryl group; 5ee-butylaluminum, ) 5ee-butylaluminum, )
Examples include tert-butylaluminum, trihexylaluminum, trioctylaluminum, triethylaluminum, diethylaluminum chloride, diisoglobyllaluminum chloride, diethylaluminum ethoxide, ethylaluminum sesquichloride, diethylzinc, and mixtures thereof.

In the present invention, the organometallic compound and the component (5) general formula R
The proportion of the compound represented by 3+S i -0-)-nR' is 2. Component (5) of general formula R3+ is used per mole of organometallic compound.
The compound represented by 5j-0+nR' T is usually 0.0
0.012 to 5 mol, preferably 0.01 to 2 mol per dose.

In the present invention, the organometallic compound component is combined with the organometallic compound and component (5) of the general formula R3(-8i -O+R
It can also be used as a reactant with a compound represented by n 2 '.

1 Organometallic compound and component (5) General formula R3+Si -O
When using the compound represented by +R' by reacting with the compound represented by 2, the reaction ratio 1 is the component (5) R3+ per mol of the organometallic compound.
The compound represented by Si -0-)-R'Si2n is usually 0. OO1 to 1 mol, preferably 0.01 to 2 mol, is used.

1 The amount of the product obtained by reacting the compound represented by the general formula R3 (-8i-0+R' with the sheet metal compound) is such that Si: Ti is 01 to 100: based on the titanium compound in the catalyst component CD. 1, preferably in the range of 0.3 to 20:1.

1 Organometallic compound and component (5) General formula R3+S i −
There are no particular restrictions on the method for obtaining the reaction product with the compound represented by 2 in 0+R'. There is also a method of causing the reaction by contacting at a temperature for 5 minutes to 20 hours.

In the present invention, the amount of the metal compound used is not particularly limited, but it is usually 0.1 to 1.0% relative to the titanium compound.
000 moles can be used.

The olefin polymerization reaction using the catalyst of the present invention is carried out in the same manner as the olefin polymerization reaction using a conventional Ziegler type catalyst. All reactions are carried out in the gas phase, in the presence of an inert solvent, or in the monomer itself as a solvent in the absence of oxygen, water, and the like. The olefin polymerization conditions are a temperature of 20°C to 600°C, preferably 40°C to 180°C, and a pressure of normal pressure to 70 K9/c.
rl-G, preferably 2 K9/7φG to 60 R
4/c small G. Although the molecular weight can be adjusted to some extent by changing the polymerization conditions such as the polymerization temperature and the molar ratio of the catalyst, it is effectively carried out by adding hydrogen to the polymerization thread. Of course, using the catalyst of the present invention, a two-step or more multi-step polymerization reaction with different polymerization conditions such as hydrogen concentration and polymerization temperature can be carried out without any hindrance.

The method of the present invention is applicable to the polymerization of all olefins that can be polymerized with Ziegler's catalyst, such as the homopolymerization of α-olefins such as ethylene, propylene, butene-1,4-methylpentene-1, and the polymerization of ethylene and propylene. , random and block copolymerization of ethylene and butene-1, propylene and butene-1, etc. Copolymerization with dienes, such as copolymerization of ethylene and butadiene, ethylene and 1,4-hexadiene, etc., is also preferably carried out for the purpose of modifying polyolefins.

In the present invention, α-olefins having 6 to 8 carbon atoms can be particularly effectively used for polymerization or copolymerization with good stereoregularity.

Examples will be described below, but these are for illustrative purposes to carry out the present invention, and the present invention is not limited thereto.

(a) Synthesis of solid catalyst component [I] Anhydrous magnesium 10f (105 mmol), vinyltriethoxysilane 1.74 ml. (a8 mmol)
and 7.2 d (46 mmol) of triphenyl phosphite were placed in a stainless steel pot with an internal volume of 400 m1 containing 25 stainless steel balls with a finch diameter, and ball milling was performed for 20 hours in a nitrogen atmosphere chamber. Ta. The obtained co-milled material was placed in a 300 mA round bottom flask under a nitrogen atmosphere, and titanium tetrachloride 50 me
and 750 rJ of 1,2-dichloroethane at 80°C.
I pressed my finger on it for 2 hours and it reacted. Subsequently, the product was washed with Kisan to remove unreacted titanium tetrachloride, and then dried under reduced pressure to obtain a solid catalyst component CI). The obtained solid catalyst component [1
] 1y contained 25■ titanium.

(b) Polymerization A 3 t stainless steel autoclave equipped with an induction stirrer was purged with nitrogen, 1500 yd of hexane was added, 2.5 mmol of triethylaluminum, 1.4 mmol of phenyltriethoxysilane and the above solid catalyst component CI) 20 Add ■, and hydrogen is 0.05 in gas phase partial pressure.
After charging so that it becomes K9/crl, 50
The temperature was raised to ℃. At the vapor pressure of hexane, the system is 0.5 Kg/
cih G, but then the total pressure of propylene is 7 Ki
With the ability to become n・G, he staked out and started polymerization. Total pressure is 7
Propylene was continuously introduced so that the ratio was 9/Rin.G, and polymerization was carried out for 2 hours.

After 1 cup, excess propylene was discharged, cooled, and the contents were taken out and dried to obtain white polypropylene 2197.

This is the total amount of the product, including the amorphous material.

Catalyst activity is 840v polypropylene/f solid/hr-
C3H6 pressure, 53.7 +<9 polypropylene/?
Ti a hr-C3H6 pressure, including the solvent-soluble pure polymer, the total extraction residue with boiling n-hebutane (all II
) is 97.6%, and the melt flow index (M
FI) is a? Met. Compared with Comparative Examples 1 and 2, both the catalyst activity and the total extraction residue were higher.

Comparative Example 1 A solid catalyst component was synthesized in the same manner as in Example 1, except that triphenyl phosphite was used sparingly, and the same as in Example 1, except that the amount of catalyst used was 50 ■. Propylene was shared using the following method. The results are shown in Table 2.

Comparative Example 2 A solid catalyst component was synthesized in the same manner as in Example 1, except that vinyltriethoxysilane was used less frequently, and propylene was polymerized in the same manner as in Comparative Example 1. The results are shown in Table 2.

Examples 2 to 6 The same procedure as in Example 1 was carried out, except that in the synthesis of the solid catalyst component [■] of Example 1, various phosphorus compounds shown in Table 1 were used in place of triphenyl phosphite. A solid catalyst component was synthesized by the method, and propylene was polymerized in the same manner as in Example 1. The results are shown in Table 1.

Example 7~? The solid catalyst component was prepared in the same manner as in Example 1, except that various phosphorus compounds shown in Table 1 were used instead of triphenyl phosphite in the synthesis of the national catalyst component [1) in Example 1. Polymerization of propylene was carried out in the same manner as in Example 1, except that the amount of catalyst was 50 mg. The results are shown in Table 1.

Comparative Example 3 The same method as in Example 1 was used except that trinoenyl phosphate was used instead of triphenyl phosphite in the synthesis of the solid catalyst component in Example 1, and the amount of catalyst was changed to somg. Polymerization of propylene was carried out. The results are shown in Table 2.

Example 10 A solid catalyst component was synthesized in the same manner as in Example 1, except that allyltriethoxysilane was used instead of vinyltriethoxysilane in the synthesis of solid catalyst component [I] in Example 1. , Propylene was polymerized in the same manner as in Example 1. The results are shown in Table 1.

Example 11 A 6-ton stainless steel autoclave equipped with an induction stirrer was purged with nitrogen, 1500 mA of hexane was added, 2.5 mmol of triethylaluminum and 1.4 mmol of phenyltriethoxysilane were added, and the autoclave was heated with
The temperature was raised to 0°C and the reaction was carried out for 30 minutes. Thereafter, the mixture was cooled to room temperature, 20 cm of the catalyst of Example B was added, and hydrogen was charged so that the gas phase partial pressure was 0.05 Kq/l:tA, and the temperature was raised to 50° C. without stirring. The vapor pressure of hexane brought the system to 0.5 K7/d-G, and propylene was then added to the system until the total pressure reached 7.7/cni-G to initiate polymerization. The following steps were carried out in the same manner as in Example 1. The results are shown in Table 1.

Procedural amendment April 1, 1980 Director of the Patent Office Kazuo Wakasugi 1. Indication of the case 1988 Patent Application No. 3559 2. Name of the invention Process for producing polyolefin 3. Person making the amendment 6. Amendment Column 7 for claims and detailed description of the invention in the subject specification
, Contents of amendment (1) The entire scope of the claims shall be amended as shown in the appendix.

(2) The description shall be amended as follows.

However, the above (deleted) is excluded from the same book.

(3) Add "C4H90P(OC6H5)2" in the component (3) column of Example 4 in Table 1 on page 30 of the same book to [$C4H90P
(OC6H5)2”.

Claims [I] (1) Magnesium halide 1 or all halogen atoms, R4 represents a hydrocarbonized water wood HM* having 1 to 24 carbon atoms. n is 1≦n≦30. ), and (3) a compound represented by the general formula PCOR'') (where R5 represents a hydrocarbon residue having 1 to 24 carbon atoms, and R5 may be the same or different) (4) a solid catalyst component obtained by completely supporting a titanium compound on the solid substance obtained by the process, [■] an organometallic compound, and 7?1 R3 is a hydrocarbon residue having 1 to 24 carbon atoms, an alkoxy group,
All hydrogen or halogen atoms R4 has 1 to 24 carbon atoms
All hydrocarbon residues are shown. n is 1≦n≦30. ) A method for producing a polyolefin, which is characterized by polymerizing or copolymerizing an α-olefin using a catalyst formed by combining compounds represented by the following.

Procedural amendment September 20, 1980 Mr. Kazuo Wakasugi, Commissioner of the Japan Patent Office 1. Indication of the case 1988 Patent Application No. 3559 2. Name of the invention Process for producing polyolefin 3. Relationship with the amended person case Patent applicant Name (444) Nippon Oil Co., Ltd. 5, Subject of amendment z'nee' BA detailed explanation of the invention 6, Contents of amendment

Claims (1)

[Claims] CI':l (1) Magnesium halide 1 (2) General formula R3(-8i-0-)-nR' (
Here, R1, R2, 2 R3 are hydrocarbon residues having 1 to 24 carbon atoms, alkoxy groups,
Hydrogen indicates a halogen atom, and R4 has 1 to 24 carbon atoms.
represents a hydrocarbon group. n is 1≦n≦30. ) and O. (3) General formula P(OR5)3 (Here, R5 represents a hydrocarbon residue having 1 to 24 carbon atoms, and R5 may be the same or different.) A solid catalyst component obtained by supporting (4) a titanium compound on a solid substance obtained by contacting a compound represented by [n'l]
Organometallic compound, and 1 010 (5) General formula R3(7Si-0-)-R
' (Here, R1, R2, 2 R3 are hydrocarbon residues having 1 to 24 carbon atoms, alkoxy groups,
Represents hydrogen or halogen atom, R4 has 1 to 24 carbon atoms
The hydrocarbon residue of n is 1≦n≦60. 1. A method for producing a polyolefin, which comprises monopolymerizing or copolymerizing an α-olefin using a catalyst comprising a combination of compounds represented by the following formulas.