JP2006077261A - Ethylenic polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ethylenic polymer having excellent moldability. <P>SOLUTION: The ethylenic polymer has 0.880-0.980 g/cm<SP>3</SP>density, 0.01-100 g/10 min melt flow rate under 2.16 kg load and >1.40 swell ratio, and satisfies a relation between a melt tension [MT (g)] and the melt flow rate [MFR (g/10 min)] of MT≥6×MFR<SP>-0.36</SP>, and a relation between a fluidity index [FI (1/sec)] defined by a shear rate when the shear stress of a molten polymer at 190°C reaches 2.4×10<SP>6</SP>dyne/cm<SP>2</SP>and the melt flow rate [MFR (g/10 min)] of FI≥500×MFR<SP>0.51</SP>. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a novel ethylene polymer, and more particularly to an ethylene polymer excellent in moldability.

  Ethylene polymers such as ethylene homopolymers and ethylene / α-olefin copolymers are molded by various molding methods and used for various purposes. These ethylene-based polymers have different characteristics depending on the molding method and application. For example, when an inflation film is to be molded at high speed, an ethylene polymer having a high melt tension must be selected for the molecular weight in order to stably perform high speed molding without bubble fluctuation or tearing. Don't be. Similar characteristics are necessary to prevent sagging or tearing in hollow molding or to minimize width drop in T-die molding. In addition, in such extrusion molding, good fluidity under a high shear force during extrusion is important from the viewpoint of the quality of the molded product and reduction of power consumption during molding.

  By the way, the high-pressure low-density polyethylene is used for applications such as a film and a hollow container because it has a higher melt tension than an ethylene polymer produced using a Ziegler-type catalyst. However, high-pressure low-density polyethylene is inferior in mechanical strength such as tensile strength, tear strength, and impact strength.

  On the other hand, among Ziegler-type catalyst systems, an ethylene polymer obtained using a titanium catalyst has a drawback of low melt tension. Therefore, a method for improving the melt tension and the expansion ratio (die swell ratio) to improve the moldability has been proposed (see Patent Documents 1 and 2). However, in general, an ethylene polymer obtained with a titanium catalyst, particularly a low density ethylene polymer, has a problem that the composition distribution is wide and a molded product such as a film is sticky.

  Among Ziegler type catalyst systems, it is known that an ethylene polymer obtained by using a metallocene catalyst system has advantages such as a narrow composition distribution and a molded article such as a film having less stickiness. However, an ethylene polymer obtained using a metallocene catalyst system has a narrow molecular weight distribution, so there is a concern that the fluidity during extrusion molding is poor.

Therefore, if an ethylene polymer having excellent melt tension, high fluidity, and narrow composition distribution appears, its industrial value is extremely high.
As a result of intensive studies in view of such circumstances, the present inventors have found that the density, the melt flow rate and the swell ratio are in a certain range, and the melt tension and the melt flow rate, the fluidity index and the melt flow rate are It has been found that ethylene polymers satisfying a certain relationship are excellent in moldability, and the present invention has been completed.
JP 56-90810 A JP 60-106806 A

  An object of the present invention is to provide an ethylene polymer having excellent moldability.

The ethylene polymer according to the present invention is:
(1) The density is in the range of 0.880 to 0.980 g / cm ³ ,
(2) The melt flow rate at 190 ° C. and a load of 2.16 kg is in the range of 0.01 to 100 g / 10 min.
(3) The melt tension (MT (g)) and the melt flow rate (MFR (g / 10 minutes)) satisfy the relationship represented by the following formula,
MT ≧ 6 × MFR ^-0.36
(4) Fluidity index (FI (1 / second)) defined by the shear rate when the shear stress at 190 ° C. of the molten polymer reaches 2.4 × 10 ⁶ dyne / cm ² , and the melt flow rate (MFR (g / 10 min)) satisfies the relationship represented by the following formula,
FI ≧ 500 × MFR ^0.51
(5) The swell ratio exceeds 1.40.

Such an ethylene polymer is, for example,
(A) a mixture of two diastereoisomers of a transition metal compound represented by the following general formula (I);
(B) It can manufacture with the catalyst for olefin polymerization containing an organoaluminum oxy compound.

(In the formula, M represents a transition metal atom of Group 4 of the periodic table,
R ¹ and R ² may be the same or different from each other and each represents a hydrocarbon group or a silicon-containing group;
m and n may be the same as or different from each other, and are integers of 1 to 3,
when m is 2 or 3, the plurality of R ¹ may be the same or different from each other;
when n is 2 or 3, the plurality of R ² may be the same or different from each other;
The types of R ¹ and R ² and the position on the cyclopentadienyl ring are the types and positions where diastereoisomers exist,
X ¹ and X ² may be the same or different from each other and each represents a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, an aryloxy group, a trialkylsilyl group, a sulfur-containing group, a halogen atom or a hydrogen atom. ,
Y represents a divalent hydrocarbon group or a divalent silicon-containing group. )

  The ethylene-based polymer of the present invention is excellent in melt tension and fluidity, and has an excellent balance between melt tension and fluidity, and thus is excellent in moldability.

Hereinafter, the ethylene polymer according to the present invention will be specifically described.
The ethylene polymer according to the present invention is an ethylene homopolymer or a random copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms.

In such an ethylene polymer, the structural unit derived from ethylene is present in an amount of 65 to 100% by weight, preferably 70 to 98% by weight, more preferably 75 to 96% by weight, and 3 carbon atoms. It is desirable that the structural unit derived from the α-olefin of ˜20 is present in an amount of 0 to 35% by weight, preferably 2 to 30% by weight, more preferably 4 to 25% by weight.

Here, the α-olefin having 3 to 20 carbon atoms includes propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, Examples include 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like.

The ethylene polymer according to the present invention has a density of 0.880 to 0.980 g / cm ³ , preferably 0.885 to 0.950 g / cm ³ , more preferably 0.890 to 0.940 g / cm ^3. The melt flow rate is in the range of 0.01 to 100 g / 10 minutes, preferably 0.03 to 70 g / 10 minutes, more preferably 0.05 to 50 g / 10 minutes.

The ethylene polymer according to the present invention has a melt tension (MT (g)) and a melt flow rate (MFR (g / 10 min)) represented by the following formula.
MT ≧ 6 × MFR ^-0.36
Preferably MT ≧ 6.5 × MFR ^−0.36
More preferably MT ≧ 7 × MFR ^-0.36
The relationship indicated by is satisfied.

  Thus, the ethylene polymer satisfying the above relationship between the melt tension and the melt flow rate has a high melt tension for the molecular weight and good moldability as compared with the conventional ethylene polymer.

The ethylene polymer according to the present invention has a fluidity index (FI (1 / second) defined by a shear rate at which a shear stress of a molten polymer at 190 ° C. reaches 2.4 × 10 ⁶ dyne / cm ^2. )) And melt flow rate (MFR (g / 10 min))
FI ≧ 500 × MFR ^0.51
Preferably FI ≧ 700 × MFR ^0.51
More preferably, FI ≧ 1000 × MFR ^0.51
The relationship indicated by is satisfied.

  If an ethylene-based polymer having a narrow composition distribution is to be produced by the prior art, generally the molecular weight distribution is also narrowed at the same time, so that the fluidity is deteriorated and the fluidity index is decreased. Since the ethylene polymer of the present invention satisfies the above relationship between the fluidity index and the melt flow rate, a low stress is maintained up to a high shear rate, and the moldability is good.

The swell ratio of the ethylene polymer according to the present invention exceeds 1.40, preferably exceeds 1.45, more preferably exceeds 1.50.
Examples of the ethylene polymer having the above characteristics include (a) a mixture of two diastereoisomers of a transition metal compound represented by the following formula (I),
(B) Using an olefin polymerization catalyst containing an organoaluminum oxy compound, polymerization is performed so that the density of a polymer from which ethylene can be obtained is 0.880 to 0.980 g / cm ³ , or ethylene and the number of carbon atoms Can be produced by copolymerizing a 3 to 20 α-olefin such that the density of the resulting copolymer is 0.880 to 0.980 g / cm ³ .

Next, each component which forms the catalyst for olefin polymerization used for manufacture of the ethylene-type polymer which concerns on this invention is demonstrated concretely.
As the transition metal compound catalyst component used for the olefin polymerization catalyst, a transition metal compound represented by the following formula (I) is used.

In the formula, M represents a transition metal atom of Group 4 of the periodic table, specifically titanium, zirconium or hafnium, preferably zirconium.
R ¹ and R ² may be the same or different from each other, and each represents a hydrocarbon group or a silicon-containing group.

  Examples of the hydrocarbon group include an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, an aryl group, and more specifically, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec- Alkyl groups having 1 to 20 carbon atoms such as butyl, t-butyl, pentyl, hexyl, octyl, 2-ethylhexyl, nonyl, decyl, dodecyl, and eicosyl; and 4 carbon atoms such as cyclopentyl, cyclohexyl, norbornyl, and adamantyl A cycloalkyl group having 20 to 20 carbon atoms; an alkenyl group having 2 to 20 carbon atoms such as vinyl, propenyl, cyclohexenyl and the like; an aralkyl group having 7 to 20 carbon atoms such as benzyl, phenylethyl, phenylpropyl and neophyll; phenyl, Tolyl, dimethylphenyl, trimethylphenyl, ethyl Eniru, propylphenyl, biphenyl, naphthyl, methylnaphthyl, anthryl, and an aryl group having a carbon number of 6 to 20 and phenanthryl. These hydrocarbon groups may be substituted by halogen.

  Silicon-containing groups include monohydrocarbon-substituted silyl such as methylsilyl and phenylsilyl; dihydrocarbon-substituted silyl such as dimethylsilyl and diphenylsilyl; trimethylsilyl, triethylsilyl, tripropylsilyl, tricyclohexylsilyl, triphenylsilyl, dimethylphenyl Trihydrocarbon-substituted silyls such as silyl, methyldiphenylsilyl, tolylsilyl, trinaphthylsilyl; silyl ethers of hydrocarbon-substituted silyls such as trimethylsilyl ether; silicon-substituted alkyl groups such as trimethylsilylmethyl; silicon-substituted aryl groups such as trimethylphenyl Etc.

  Among these, a hydrocarbon group is preferable, more preferably an alkyl group, still more preferably an alkyl group having 1 to 12 carbon atoms, and particularly preferably a methyl group or an ethyl group.

m and n may be the same as or different from each other, and are integers of 1 to 3,
When m is 2 or 3, the plurality of R ¹ may be the same or different from each other, and when n is 2 or 3, the plurality of R ² may be the same or different from each other.

The types of R ¹ and R ² and the position on the cyclopentadienyl ring are the types and positions where diastereoisomers exist.
Here, the diastereoisomers are two types of isomers formed at the stage where the bridged biscyclopentadienyl ligand is coordinated to the transition metal, and are represented by the following general formulas (Ia) and (I -b) Like the compounds represented by -b), the ligands are the same, but the compounds have different combinations of coordination planes of the two cyclopentadienyl rings to the transition metal, and are not enantiomers of each other Refers to a compound.

X ¹ and X ² may be the same or different from each other and each represents a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, an aryloxy group, a trialkylsilyl group, a sulfur-containing group, a halogen atom or a hydrogen atom. .

Examples of the hydrocarbon group having 1 to 20 carbon atoms include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and the like. More specifically, the same groups as those for R ¹ and R ² described above. Can be illustrated.

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

  Examples of the aryloxy group include phenoxy. Examples of the trialkylsilyl group include trimethylsilyl, triethylsilyl, triphenylsilyl and the like.

  Sulfur-containing groups include methyl sulfonate, trifluoromethane sulfonate, phenyl sulfonate, benzyl sulfonate, p-toluene sulfonate, trimethyl benzene sulfonate, triisobutyl benzene sulfonate, p-chloro. Sulfonato groups such as benzene sulfonate and pentafluorobenzene sulfonate; methyl sulfinate, phenyl sulfinate, benzene sulfinate, p-toluene sulfinate, trimethylbenzene sulfinate, pentafluorobenzene sulfinate And sulfinate groups such as

Halogen atoms are fluorine, chlorine, bromine and iodine.
Y is a divalent hydrocarbon group or a divalent silicon-containing group.
Divalent hydrocarbon groups include methylene, dimethylmethylene, 1,2-ethylene, dimethyl-1,2-ethylene, 1,3-trimethylene, 1,4-tetramethylene, 1,2-cyclohexylene, 1, Divalent hydrocarbons having 1 to 20 carbon atoms, such as alkylene groups such as 4-cyclohexylene; alkylidene groups such as isopropylidene and cyclohexylidene; arylalkylene groups such as diphenylmethylene and diphenyl-1,2-ethylene Groups.

Examples of divalent silicon-containing groups include: silylene; alkylsilylene groups such as methylsilylene, dimethylsilylene, diethylsilylene, di (n-propyl) silylene, di (i-propyl) silylene, di (cyclohexyl) silylene; methylphenylsilylene Alkylarylsilylene groups such as diphenylsilylene, di (p-tolyl) silylene, di (p-chlorophenyl) silylene, and other arylsilylene groups; alkyldisilylene groups such as tetramethyl-1,2-disilylene; tetraphenyl-1 , 2-disilylene, etc .; alkyl disilylene groups; alkylaryl disilylene groups; and bivalent silicon-containing groups such as aryl disilylene groups.

As such a transition metal compound represented by the general formula (I),
Dimethylsilylenebis (2-methylcyclopentadienyl) zirconium dichloride,
Dimethylsilylene bis (2-ethylcyclopentadienyl) zirconium dichloride,
Dimethylsilylenebis (3-methylcyclopentadienyl) zirconium dichloride,
Dimethylsilylenebis (3-methylcyclopentadienyl) zirconium dibromide,
Dimethylsilylene bis (3-methylcyclopentadienyl) zirconium dimethoxide,
Dimethylsilylenebis (3-methylcyclopentadienyl) zirconium methoxychloride,
Dimethylsilylenebis (3-methylcyclopentadienyl) dimethylzirconium,
Dimethylsilylenebis (3-methylcyclopentadienyl) diphenylzirconium,
Dimethylsilylenebis (3-methylcyclopentadienyl) methylzirconium monochloride,
Dimethylsilylene bis (3-methylcyclopentadienyl) zirconium bis (methyl sulfonate),
Dimethylsilylene bis (3-methylcyclopentadienyl) zirconium bis (p-toluenesulfonate),
Dimethylsilylene bis (3-methylcyclopentadienyl) zirconium bis (trifluoromethanesulfonate),
Dimethylsilylene bis (3-ethylcyclopentadienyl) zirconium dichloride,
Dimethylsilylene bis (2,3-dimethylcyclopentadienyl) zirconium dichloride,
Dimethylsilylene bis (2,4-dimethylcyclopentadienyl) zirconium dichloride,
Dimethylsilylene bis (2,4-diethylcyclopentadienyl) zirconium dichloride,
Dimethylsilylenebis (2,4-ethyl, methylcyclopentadienyl) zirconium dichloride,
Dimethylsilylenebis (2,3,4-trimethylcyclopentadienyl) zirconium dichloride,
Dimethylsilylene bis (2,3,5-trimethylcyclopentadienyl) zirconium dichloride,
Dimethylsilylenebis (2,3,5-triethylcyclopentadienyl) zirconium dichloride,
Dimethylsilylene bis (2,3,5-ethyl, dimethylcyclopentadienyl) zirconium dichloride,
Dimethylsilylene bis (2,3,5-diethyl, methylcyclopentadienyl) zirconium dichloride,
Dimethylsilylene (2-methylcyclopentadienyl) (3-methylcyclopentadienyl) zirconium dichloride,
Dimethylsilylene (3-methylcyclopentadienyl) (2,4-dimethylcyclopentadienyl) zirconium dichloride,
Diphenylsilylenebis (3-methylcyclopentadienyl) zirconium dichloride,
Methylphenylsilylenebis (3-methylcyclopentadienyl) zirconium dichloride,
Ethylenebis (3-methylcyclopentadienyl) zirconium dichloride,
Ethylenebis (2,4-dimethylcyclopentadienyl) zirconium dichloride,
Ethylenebis (2,4,5-trimethylcyclopentadienyl) zirconium dichloride,
Isopropylidenebis (3-methylcyclopentadienyl) zirconium dichloride,
Isopropylidenebis (2,4-dimethylcyclopentadienyl) zirconium dichloride,
Isopropylidenebis (2,4,5-trimethylcyclopentadienyl) zirconium dichloride,
Cyclohexylidenebis (3-methylcyclopentadienyl) zirconium dichloride,
And diphenylmethylene (3-methylcyclopentadienyl) zirconium dichloride.
In the present invention, a transition metal compound in which zirconium metal is replaced with titanium metal or hafnium metal in the above-described zirconium compound can be used.

Among these transition metal compounds represented by the general formula (I),
Dimethylsilylenebis (3-methylcyclopentadienyl) zirconium dichloride,
Dimethylsilylene bis (3-ethylcyclopentadienyl) zirconium dichloride,
Dimethylsilylene bis (2,4-dimethylcyclopentadienyl) zirconium dichloride,
Ethylene bis (3-methylcyclopentadienyl) zirconium dichloride is particularly preferred.

The transition metal catalyst component (a) used in the present invention is a mixture of two diastereoisomers of the transition metal compound represented by the general formula (I), for example, dimethylsilylene bis (2-methylcyclopenta). Dienyl) zirconium dichloride is dimethylsilylene (2-methylcyclopentadienyl) (2'-methylcyclopentadienyl) zirconium dichloride and dimethylsilylene (2-methylcyclopentadienyl) (5'-methylcyclopenta Dienyl) represents a mixture with zirconium dichloride.

  The mixing ratio of each isomer is 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 80/20, and particularly preferably 30/70 to 70/30. . As the transition metal catalyst component (a) used in the present invention, it is possible to use a mixture of isomers produced at the time of synthesizing the general formula (I) at the same production ratio. This is an efficient method that does not require a separation process of isomers.

Hereinafter, a mixture of two kinds of diastereoisomers of the transition metal compound represented by the general formula (I) may be referred to as component (a).
The (b) organoaluminum oxy compound (hereinafter sometimes referred to as “component (b)”) used in the olefin polymerization catalyst may be a conventionally known benzene-soluble aluminoxane, or JP-A-2-276807. It may be a benzene-insoluble organoaluminum oxy compound as disclosed in the above.

A conventionally well-known aluminoxane can be manufactured by the following methods, for example.
(1) Compounds containing adsorbed water or salts containing water of crystallization, such as magnesium chloride hydrate, copper sulfate hydrate, aluminum sulfate hydrate, nickel sulfate hydrate, first cerium chloride hydrate, etc. A method of reacting adsorbed water or crystal water with an organoaluminum compound by adding an organoaluminum compound such as trialkylaluminum to the above suspension of the hydrocarbon medium.
(2) A method of allowing water, ice or water vapor to act directly on an organoaluminum compound such as trialkylaluminum in a medium such as benzene, toluene, ethyl ether or tetrahydrofuran.
(3) A method in which an organotin oxide such as dimethyltin oxide or dibutyltin oxide is reacted with an organoaluminum compound such as trialkylaluminum in a medium such as decane, benzene, or toluene.

  In addition, this aluminoxane may contain a small amount of organometallic components. Further, the solvent or unreacted organoaluminum compound may be removed by distillation from the recovered solution of the above aluminoxane and then redissolved in the solvent.

Specific examples of organoaluminum compounds used in the production of aluminoxane include trimethylaluminum, triethylaluminum, tripropylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, trisec-butylaluminum, tritert- Trialkylaluminums such as butylaluminum, tripentylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum;
Tricycloalkylaluminum such as tricyclohexylaluminum, tricyclooctylaluminum;
Dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, diethylaluminum bromide, diisobutylaluminum chloride;
Dialkylaluminum hydrides such as diethylaluminum hydride, diisobutylaluminum hydride;
Dialkylaluminum alkoxides such as dimethylaluminum methoxide and diethylaluminum ethoxide;
Examples thereof include dialkylaluminum aryloxides such as diethylaluminum phenoxide.

Of these, trialkylaluminum and tricycloalkylaluminum are particularly preferred.
Further, as the organoaluminum compound represented by the following general formula _{(i-C 4 H 9)} x Al y (C 5 H 10) z
(X, y, z are positive numbers and z ≧ 2x)
Isoprenylaluminum represented by the formula can also be used.

  The organoaluminum compounds as described above are used alone or in combination. Solvents used in the production of aluminoxane include aromatic hydrocarbons such as benzene, toluene, xylene, cumene, and cymene, aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane, dodecane, hexadecane, and octadecane, Cycloaliphatic hydrocarbons such as cyclopentane, cyclohexane, cyclooctane and methylcyclopentane, petroleum fractions such as gasoline, kerosene and light oil or halides of the above aromatic hydrocarbons, aliphatic hydrocarbons and alicyclic hydrocarbons, among others , Hydrocarbon solvents such as chlorinated products and brominated products. In addition, ethers such as ethyl ether and tetrahydrofuran can also be used. Of these solvents, aromatic hydrocarbons are particularly preferred.

  The benzene-insoluble organoaluminum oxy compound has an Al component dissolved in benzene at 60 ° C. of 10% or less, preferably 5% or less, particularly preferably 2% or less in terms of Al atom, and is insoluble or difficult to benzene. It is soluble.

The solubility of the organoaluminum oxy compound in benzene is determined by suspending the organoaluminum oxy compound corresponding to 100 milligram atoms of Al in 100 ml of benzene.
After mixing for 6 hours at 60 ° C. with stirring, filtration was performed hot at 60 ° C. using a jacketed G-5 glass filter, and the solid part separated on the filter was washed 4 times with 50 ml of benzene at 60 ° C. It can be determined by measuring the abundance (x mmol) of Al atoms present in the total filtrate after washing (x%).

  The olefin polymerization catalyst used in the production of the ethylene polymer according to the present invention comprises (a) a mixture of two diastereoisomers of the transition metal compound represented by the general formula (I), and (b ) And an organoaluminum oxy compound. If necessary, at least one of the component (a) and the component (b) may be used for polymerization as a solid catalyst (c) supported on a carrier as described below. Good.

The carrier (c) used as necessary is an inorganic or organic compound, and a granular or particulate solid having a particle size of 10 to 300 μm, preferably 20 to 200 μm is used. Of these, porous oxides are preferred as the inorganic compounds. Specifically, SiO ₂ , Al ₂ O ₃ , MgO, ZrO ₂ , TiO ₂ , B ₂ O ₃ , CaO, ZnO, BaO, ThO ₂ etc. or these Illustrate mixtures such as SiO ₂ —MgO, SiO ₂ —Al ₂ O ₃ , SiO ₂ —TiO ₂ , SiO ₂ —V ₂ O ₅ , SiO ₂ —Cr ₂ O ₃ , SiO ₂ —TiO ₂ —MgO, etc. Can do. Of these, those containing as a main component at least one component selected from the group consisting of SiO ₂ and Al ₂ O ₃ are preferred.

The inorganic oxide includes a small amount of Na ₂ CO 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 , Al (NO ₃ ) ₃ , Na ₂ O, K ₂ O, Li ₂ O and other carbonates, sulfates, nitrates and oxide components may be contained.

Such a carrier (c) has different properties depending on the type and production method, but the carrier preferably used in the present invention has a specific surface area of 50 to 1000 m ² / g, preferably 100 to 700 m ² / g, The volume is desirably 0.3 to 2.5 cm ³ / g. The carrier is used after being calcined at a temperature of 100 to 1000 ° C., preferably 150 to 700 ° C., if necessary.

  In such a carrier (c), the amount of adsorbed water is desirably less than 1.0% by weight, preferably less than 0.5% by weight, and the surface hydroxyl group is 1.0% by weight or more, preferably 1.5 to 4%. It is desirable that the amount be 0.0% by weight, particularly preferably 2.0 to 3.5% by weight.

Here, the amount of adsorbed water (wt%) and the amount of surface hydroxyl groups (wt%) of the carrier (c) are determined as follows.
[Amount of adsorbed water]
The weight loss when dried at 200 ° C. under normal pressure and nitrogen flow for 4 hours is determined and shown as a percentage of the weight before drying.
[Surface hydroxyl group content]
The weight of the support obtained by drying for 4 hours at 200 ° C. under normal pressure and nitrogen flow is X (g), and the surface hydroxyl group obtained by calcining the support for 20 hours at 1000 ° C. disappears. The weight of the fired product is Y (g) and is calculated according to the following formula.

Surface hydroxyl group content (% by weight) = {(XY) / X} × 100
Furthermore, examples of the carrier (c) include granular or fine particle solids of organic compounds having a particle size in the range of 10 to 300 μm. Examples of these organic compounds include (co) polymers or vinylcyclohexane, which are mainly composed of α-olefins having 2 to 14 carbon atoms such as ethylene, propylene, 1-butene and 4-methyl-1-pentene. A polymer or copolymer produced with styrene as the main component can be exemplified.

Further, as a catalyst component for forming an olefin polymerization catalyst, the following (d) organoaluminum compound can be used as necessary.
Examples of the (a) organoaluminum compound (hereinafter sometimes referred to as “component (d)”) used as necessary include an organoaluminum compound represented by the following general formula (II).

^{_{R a n AlX 3-n ...}} (II)
(In the formula, Ra represents ^a hydrocarbon group having 1 to 12 carbon atoms, X represents a halogen atom or a hydrogen atom, and n is 1 to 3).
In the general formula (II), R ^a is a hydrocarbon group having 1 to 12 carbon atoms, such as an alkyl group, a cycloalkyl group, or an aryl group. Specifically, methyl, ethyl, n-propyl, An alkyl group such as isopropyl, n-butyl, isobutyl, pentyl, hexyl, isohexyl, heptyl, nonyl and octyl, a cycloalkyl group such as cyclopentyl and cyclohexyl, and an aryl group such as phenyl and tolyl.

Specific examples of such an organoaluminum compound (d) include the following compounds.
Trialkylaluminums such as trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, trioctylaluminum, tri-2-ethylhexylaluminum;
Alkenyl aluminum such as isoprenyl aluminum;
Dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, diisopropylaluminum chloride, diisobutylaluminum chloride, dimethylaluminum bromide;
Alkylaluminum sesquichlorides such as methylaluminum sesquichloride, ethylaluminum sesquichloride, isopropylaluminum sesquichloride, butylaluminum sesquichloride, ethylaluminum sesquibromide;
Alkylaluminum dihalides such as methylaluminum dichloride, ethylaluminum dichloride, isopropylaluminum dichloride, ethylaluminum dibromide;
Dimethyl aluminum hydride, diethyl aluminum hydride, dihydrophenyl aluminum, diisopropyl aluminum hydride, di-n-butyl aluminum hydride, diisobutyl aluminum hydride, diisohexyl aluminum hydride, diphenyl aluminum hydride, dicyclohexyl aluminum hydride, di-sec-heptyl aluminum hydride, Alkyl aluminum hydrides such as di-sec-nonyl aluminum hydride.

Moreover, the compound represented by the following general formula (III) can also be used as the organoaluminum compound (d).
^{_{R a n AlY 3-n ...}} (III)
(Wherein, R ^a is the same as above, Y is —OR ^b group, —OSiR ^c ₃ group, —OAlR ^d ₂ group, —NR ^e ₂ group, —SiR ^f ₃ group or —N (R ^g )) An AlR ^h ₂ group, n is 1 to 2, R ^b , R ^c , R ^d and R ^h are methyl, ethyl, isopropyl, isobutyl, cyclohexyl, phenyl, etc., and R ^e is a hydrogen atom, methyl, Ethyl, isopropyl, phenyl, trimethylsilyl, etc., and R ^f and R ^g are methyl, ethyl, etc.)
Specific examples of such an organoaluminum compound include the following compounds.
_{^{(1) R a n Al (}} OR b) a compound represented by _3-n, e.g., dimethylaluminum methoxide, diethylaluminum ethoxide and diisobutylaluminum methoxide;
_{^{(2) R a n Al (}} OSiR c 3) a compound represented by _3-n, e.g., _{Et 2 Al (OSiMe 3),} (iso-Bu) 2 Al (OSiMe 3), (iso-Bu) 2 Al ( OSiEt ₃ ) etc .;
_{^{(3) R a n Al (}} OAlR d 2) a compound represented by _3-n, e.g.,
Et ₂ AlOAlEt ₂ , (iso-Bu) ₂ AlOAl (iso-Bu) ₂ etc .;
_{^{(4) R a n Al (}} NR e 2) a compound represented by _3-n, e.g., _{Me 2 AlNEt 2, Et 2 AlNHMe} , Me 2 AlNHEt, Et 2 AlN (Si
Me ₃ ) ₂ , (iso-Bu) ₂ AlN (SiMe ₃ ) ₂ etc .;
_{^{(5) R a n Al (}} SiR f 3) a compound represented by _3-n, such as _{(iso-Bu) 2 AlSiMe 3} ;
_{^{(6) R a n Al (}} N (R g) AlR h 2) a compound represented by _3-n, e.g., _{Et 2 AlN (Me) AlEt 2} ,
(Iso-Bu) ₂ AlN (Et) Al (iso-Bu) _{2 and the} like.

Among the organoaluminum compounds represented by the general formula (II) and (III), the general formula ^{_{R a 3 Al, R a n}} Al (OR b) 3-n, R a n Al (OAlR d 2) 3 A compound represented by _-n is preferable, and a compound in which ^Ra is an isoalkyl group and n = 2 is particularly preferable.

  Examples of the olefin polymerization catalyst used in the production of the ethylene-based polymer according to the present invention include the catalyst (i) comprising the component (a) and the component (b) as described above, and the component (a) in the carrier (c). And a catalyst comprising the catalyst (i) (catalyst component) and the component (d), the solid catalyst (ii) (solid catalyst component) and the component ( d) and the like.

The solid catalyst (ii) can be prepared by bringing the component (a), the component (b) and the carrier (c) into contact with the component (d) as necessary.
The contact of component (a), component (b) and carrier (c), and optionally component (d) can be carried out in an inert hydrocarbon solvent and used in the preparation of a catalyst. Specifically, aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, decane, dodecane, kerosene; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane; benzene, toluene, Aromatic hydrocarbons such as xylene; halogenated hydrocarbons such as ethylene chloride, chlorobenzene, and dichloromethane, or mixtures thereof.

In mixing and contacting the component (a), the component (b) and the carrier (c), and if necessary, the component (d), the component (a) is a transition metal in the component (a) per 1 g of the carrier (c). It is usually used in an amount of 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ mol, preferably 10 ⁻⁵ to 2 × 10 ⁻⁴ mol in terms of atoms, and the concentration of component (a) is in component (a). In terms of the transition metal atom, about 10 ⁻⁴ to 2 × 10 ⁻² mol / liter (solvent), preferably 2 × 10 ⁻⁴ to 10 ⁻² mol / liter (solvent). The atomic ratio (Al / M) of the aluminum atom in the component (b) and the transition metal atom (M) in the component (a) is usually 10 to 500, preferably 20 to 200. The atomic ratio (Al-d / Al-b) of the aluminum atom (Al-d) in the component (d) and the aluminum atom (Al-b) in the component (b) used as necessary is usually 0.00. The range is 02 to 3, preferably 0.05 to 1.5. The mixing temperature for mixing and contacting the components is usually −50 to 150 ° C., preferably −20 to 120 ° C., and the contact time is 1 minute to 50 hours, preferably 10 minutes to 25 hours.

The solid catalyst (ii) prepared as described above has a component (a) of 1 g per 1 g of the support (c).
It is supported in an amount of 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ gram atoms, preferably 10 ⁻⁵ to 2 × 10 ⁻⁴ gram atoms in terms of transition metal atoms in the component (a). b) and the component (d) are 10 ^{−3 to} 5 × 10 ⁻² gram atom, preferably 2 × in terms of aluminum atoms in the component (b) and the component (d) per 1 g of the carrier (c). It is preferably supported in an amount of 10 ^{−3 to} 2 × 10 ⁻² gram atoms.

The olefin polymerization catalyst may be a prepolymerization catalyst comprising component (a), component (b), carrier (c), polyolefin produced by prepolymerization, and, if necessary, component (d).
The prepolymerization catalyst is prepared by introducing an olefin into an inert hydrocarbon solvent in the presence of the above component (a), component (b), carrier (c), and component (d) as necessary. can do. It is preferable that the solid catalyst (ii) (solid catalyst component) is formed from the component (a), the component (b) and the carrier (c). In this case, in addition to the solid catalyst (ii), component (b) and / or component (d) may be further added.

  The prepolymerized catalyst may be obtained by introducing an olefin into the suspension in which the solid catalyst (ii) (solid catalyst component) described above is prepared, and the solid catalyst (ii) produced after the solid catalyst (ii) is prepared. May be separated from the suspension, after which the solid catalyst (ii) may again be suspended in an inert hydrocarbon and the olefin introduced therein.

In the prepolymerization, the component (a) is usually 10 ⁻⁶ to 2 × 10 ⁻² mol / liter (solvent), preferably 5 × 10, in terms of the transition metal atom in the component (a). ⁻⁵ to 10 ⁻² mol / liter (solvent), and component (a) is usually 5 × 10 ⁻⁶ in terms of transition metal atom in component (a) per gram of support (c). It is used in an amount of ˜5 × 10 ⁻⁴ mol, preferably 10 ⁻⁵ to 2 × 10 ⁻⁴ mol. The atomic ratio (Al / M) of the aluminum atom in the component (b) and the transition metal atom (M) in the component (a) is usually 10 to 500, preferably 20 to 200. The atomic ratio (Al-d / Al-b) of the aluminum atom (Al-d) in the component (d) and the aluminum atom (Al-b) in the component (b) used as necessary is usually 0.00. The range is 02 to 3, preferably 0.05 to 1.5.

The prepolymerization temperature is -20 to 60 ° C, preferably 0 to 50 ° C, and the prepolymerization time is 0.5 to 100 hours, preferably about 1 to 50 hours.
Examples of the olefin used in the prepolymerization include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-hexene, Examples include octene, 1-decene, 1-dodecene, 1-tetradecene and the like. Among these, ethylene alone or a combination of ethylene and an α-olefin used for polymerization is particularly preferable.

In the prepolymerization, the amount of the olefin (co) polymer to be produced is desirably 0.1 to 500 g, preferably 0.2 to 300 g, more preferably 0.5 to 200 g, per 1 g of the carrier (c). In addition, in the prepolymerization catalyst, the component (a) is about 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ gram atoms, preferably 10 ⁻⁵ to 2 × 10 ⁻⁴ gram as a transition metal atom per 1 g of the carrier (c). Supported in the amount of gram atoms, component (b) and component (d) are composed of an aluminum atom (Al) in component (b) and component (d) and a transition metal atom (M) in component (a). It is desirable that it is supported in an amount in the range of 5 to 200, preferably 10 to 150, in a molar ratio (Al / M).

The prepolymerization can be performed either batchwise or continuously, and can be performed under reduced pressure, normal pressure, or increased pressure. In the prepolymerization, the preliminary viscosity [η] measured in decalin at least 135 ° C. in the presence of hydrogen is in the range of 0.2 to 7 dl / g, preferably 0.5 to 5 dl / g. It is desirable to produce a polymer.

  The ethylene polymer according to the present invention, for example, homopolymerizes ethylene in the presence of an olefin polymerization catalyst as described above, or copolymerizes ethylene with an α-olefin having 3 to 20 carbon atoms. It is obtained by doing.

In the present invention, the polymerization is carried out in a slurry liquid phase, liquid phase or gas phase. In slurry polymerization, an inert hydrocarbon may be used as a solvent, or olefin itself may be used as a solvent.
Specific examples of the inert hydrocarbon solvent used in the slurry polymerization include aliphatic hydrocarbons such as butane, isobutane, pentane, hexane, octane, decane, dodecane, hexadecane, and octadecane; cyclopentane, methylcyclopentane, cyclohexane, Examples thereof include alicyclic hydrocarbons such as cyclooctane; aromatic hydrocarbons such as benzene, toluene and xylene; petroleum fractions such as gasoline, kerosene and light oil. Of these inert hydrocarbon media, aliphatic hydrocarbons, alicyclic hydrocarbons, petroleum fractions and the like are preferable.

When the slurry polymerization method, the liquid phase polymerization method or the gas phase polymerization method is performed, the component (a) is usually 10 ⁻⁸ to 10 ⁻³ gram atom / liter as the transition metal atom concentration in the polymerization reaction system, It is preferably used in an amount of 10 ⁻⁷ to 10 ⁻⁴ gram atom / liter. In the component (b), the molar ratio (Al / M) of the aluminum atom (Al) in the component (b) and the transition metal atom (M) in the component (a) is usually 10 to 5000, preferably It is used in such an amount as to be 20-2000.

  Moreover, when using a solid catalyst (ii) or a prepolymerization catalyst, you may add the organoaluminum oxy compound and / or (d) organoaluminum compound similar to a component (b) further. At this time, the atomic ratio (Al / M) of the aluminum atom (Al) in the organoaluminum oxy compound and the organoaluminum compound to the transition metal atom (M) in the transition metal compound (a) is preferably 5 to 300, preferably Is in the range of 10 to 200, more preferably 15 to 150.

In the present invention, when the polymerization method is carried out, the polymerization temperature is usually in the range of −50 to 200 ° C., preferably 0 to 100 ° C., and the polymerization pressure is usually normal pressure to 100 kg / cm ² , preferably The pressure is ^{2 to} 50 kg / cm ² .

  The polymerization can be carried out in any of batch, semi-continuous and continuous systems. If hydrogen is used during the main polymerization, the molecular weight of the polymer obtained can be adjusted, and a polymer having a high melt flow rate can be obtained.

  The ethylene-based polymer of the present invention is excellent in melt tension and fluidity, and has an excellent balance between melt tension and fluidity, and thus is excellent in moldability. In addition, the ethylene polymer of the present invention has a narrow composition distribution and is excellent in thermal stability.

  The ethylene polymer of the present invention includes a weather resistance stabilizer, a heat resistance stabilizer, an antistatic agent, an anti-slip agent, an anti-blocking agent, an antifogging agent, a lubricant, a pigment, and a dye as long as the object of the present invention is not impaired. In addition, additives such as a nucleating agent, a plasticizer, an anti-aging agent, a hydrochloric acid absorbent, and an antioxidant may be blended as necessary.

The ethylene polymer of the present invention is a film by extrusion molding, a composite film coated on a base film, pipes and tubes by extrusion molding, fibers, containers by blow molding, daily miscellaneous goods by injection molding, caps, etc. It can be used for applications such as large molded products by rotational molding, wire coating, and foams.

In the extrusion molding, the ethylene polymer of the present invention has a balance between melt tension and fluidity equivalent to that of the high-pressure ethylene polymer, so that the moldability is higher than that of the conventional medium-low pressure ethylene polymer. It is good. In addition, the extrusion-molded product is superior in impact strength, heat sealability, blocking resistance and the like as compared with a conventional ethylene copolymer.
An injection molded product is excellent in strength characteristics such as impact strength and environmental stress resistance. It also has excellent low temperature characteristics.

Next, physical property values used in the present invention are defined, measured, and molded.
(1) Granulation of ethylene polymer 0.05 parts of tri (2,4-di-t-butylphenyl) phosphate as a secondary antioxidant is added to 100 parts by weight of powdered ethylene polymer. Parts by weight, 0.1% by weight of n-octadecyl-3- (4′hydroxy-3 ′, 5′-di-t-butylphenyl) propinate as heat stabilizer
Then, 0.05 part by weight of calcium stearate as a hydrochloric acid absorbent is blended. Thereafter, a granulated pellet is prepared by melt extrusion at a set temperature of 180 ° C. using a conical tapered twin screw extruder manufactured by Harke.
(2) Density The strand obtained at the time of measuring the melt flow rate at 190 ° C. under a load of 2.16 kg is heat-treated at 120 ° C. for 1 hour, slowly cooled to room temperature over 1 hour, and then measured with a density gradient tube.
(3) Melt flow rate (MFR)
1 according to ASTM D1238-65T using granulated pellets of ethylene polymer
It is measured under the conditions of 90 ° C. and 2.16 kg load.
(4) Melt tension (MT)
It is determined by measuring the stress when the molten polymer is stretched at a constant speed. That is, using a granulated pellet of polymer as a measurement sample, using a MT measuring machine manufactured by Toyo Seiki Seisakusho, resin temperature 190 ° C., extrusion speed 15 mm / min, winding speed 10-20 m / min, nozzle diameter 2.09 mmφ, The nozzle length is 8 mm.
(5) Liquidity index (FI)
The flow index is defined as the shear rate at which the shear stress at 190 ° C. reaches 2.4 × 10 ⁶ dyne / cm ² . The flow index was determined by extruding the resin from the capillary while changing the shear rate and measuring the stress at that time. That is, using a sample similar to the measurement of melt tension, using a capillary flow characteristic tester manufactured by Toyo Seiki Seisakusho, the resin temperature is 190 ° C., and the shear stress range is 5 × 10 ^{4 to} 3 × 10 ⁶ dyne / cm ^2. Measured in degree.

The measurement is performed by changing the diameter of the nozzle (capillary) as follows according to the MFR (g / 10 min) of the resin to be measured.
0.5 mm when MFR> 20
1.0 mm when 20 ≧ MFR> 3
2.0 mm when 3 ≧ MFR> 0.8
3.0mm when 0.8 ≧ MFR
(6) Measurement of Swell Ratio According to ASTM D1238-65T, MFR strands measured under conditions of 190 ° C. and 2.16 kg load are collected, and a 5.0 mm portion from the tip is cut vertically. Using a micrometer, measure the diameter of the cut part at two points in the perpendicular direction. A value obtained by dividing the average value of these diameters by the nozzle diameter of 2.09 mm at the time of MFR measurement is defined as a swell ratio.
[Example]
EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.

[Preparation of solid catalyst component]
After 3.0 g of silica dried for 10 hours at 250 ° C. was suspended in 50 ml of toluene, it was cooled to 0 ° C. Thereafter, 17.8 ml of a toluene solution of methylaluminoxane (Al = 1.29 mmol / ml) was added dropwise over 30 minutes. At this time, the temperature in the system was kept at 0 ° C. Then, it was made to react at 0 degreeC for 30 minutes, then, it heated up to 95 degreeC over 30 minutes, and was made to react at the temperature for 4 hours. Thereafter, the temperature was lowered to 60 ° C., and the supernatant was removed by a decantation method.

  The solid component thus obtained was washed twice with toluene and then resuspended in 50 ml of toluene. Into this system, 11.1 ml of a toluene solution (Zr = 0.0103 mmol / ml) of dimethylsilylene bis (3-methylcyclopentadienyl) zirconium dichloride (diastereoisomer mixing ratio 1: 1) was added at 20 ° C. It was added dropwise over 30 minutes. Next, the temperature was raised to 80 ° C., and the reaction was carried out at that temperature for 2 hours. Thereafter, the supernatant was removed and washed twice with hexane to obtain a solid catalyst containing 2.3 mg of zirconium per 1 g.

[Preparation of prepolymerization catalyst]
4 g of the solid catalyst obtained above was resuspended in 200 ml of hexane. To this system, 5.0 ml of a decane solution of triisobutylaluminum (1 mmol / ml) and 0.36 g of 1-hexene were added, and ethylene was prepolymerized at 35 ° C. for 2 hours to obtain 2.2 mg per 1 g of the solid catalyst. A prepolymerized catalyst containing zirconium and prepolymerized 3 g of polyethylene was obtained.

[polymerization]
1 L of dehydrated and purified hexane was charged into a 2 liter stainless steel autoclave sufficiently purged with nitrogen, and the inside of the system was replaced with a mixed gas of ethylene and hydrogen (hydrogen content: 0.1 mol%).

  Next, the system was heated to 60 ° C., 1.5 mmol of triisobutylaluminum, 40 ml of 1-hexane, and 0.23 mg atom in terms of zirconium atom were added to the prepolymerized catalyst prepared as described above.

Thereafter, a mixed gas of ethylene and hydrogen having the same composition as above was introduced, and polymerization was started at a total pressure of 8 kg / cm ² -G. Thereafter, only the mixed gas was supplied, the total pressure was kept at 8 kg / cm ² -G, and polymerization was carried out at 70 ° C. for 1.5 hours.

After completion of the polymerization, the polymer was filtered and dried at 80 ° C. overnight. As a result, 115 g of an ethylene / 1-hexene copolymer having a melt flow rate measured at 190 ° C. under a load of 2.16 kg of 1.8 g / 10 min and 0.929 g / cm ³ was obtained.
The resulting granulated pellets of copolymer had a melt flow rate of 2.2 g / 10 min, a melt tension of 5.6 g, and a fluidity index of 1700 s ⁻¹ .

[polymerization]
Except for changing the addition amount of 1-hexene to 30 ml, in the same manner as in Example 1, 140 g of ethylene / 1-hexene copolymer having a melt flow rate of 3.7 g / 10 min and a density of 0.935 g / cm ³ was obtained. Obtained.
The resulting granulated pellets of copolymer had a melt flow rate of 4.5 g / 10 min, a melt tension of 4.2 g, and a fluidity index of 2580 s ⁻¹ .

[polymerization]
The melt flow rate was 2.0 g / 10 min and the density was 0.961 g / cm, as in Example 1, except that 1-hexene was not added and the mixed gas of ethylene and hydrogen was changed to 0.05 mol%. 76 g of ethylene polymer ³ was obtained.
The resulting granulated pellets of copolymer had a melt flow rate of 2.3 g / 10 min, a melt tension of 8.2 g, and a fluidity index of 1620 s ⁻¹ .

[polymerization]
Except for changing the mixed gas of ethylene and hydrogen to 0.07 mol%, the same procedure as in Example 3 was carried out to obtain 78 g of an ethylene polymer having a melt flow rate of 4.7 g / 10 min and a density of 0.962 g / cm ^3. It was.
The resulting granulated pellets of copolymer had a melt flow rate of 5.7 g / 10 min, a melt tension of 4.0 g, and a fluidity index of 3120 s ⁻¹ .
The results are shown in Table 1.

  It can be seen that the ethylene polymers obtained in Examples 1 to 4 have good melt tension and fluidity and are very excellent in moldability.

Claims (2)

(1) The density is in the range of 0.880 to 0.980 g / cm ³ ,
(2) The melt flow rate at 190 ° C. and a load of 2.16 kg is in the range of 0.01 to 100 g / 10 min.
(3) The melt tension (MT (g)) and the melt flow rate (MFR (g / 10 minutes)) satisfy the relationship represented by the following formula, and MT ≧ 6 × MFR ^−0.36
(4) Fluidity index (FI (1 / second)) defined by the shear rate when the shear stress at 190 ° C. of the molten polymer reaches 2.4 × 10 ⁶ dyne / cm ² , and the melt flow rate (MFR (g / 10 min)) satisfies the relationship represented by the following formula,
FI ≧ 500 × MFR ^0.51
(5) An ethylene polymer having a swell ratio exceeding 1.40. (A) a mixture of two diastereoisomers of a transition metal compound represented by the following general formula (I);
The ethylene polymer according to claim 1, which is produced by an olefin polymerization catalyst containing (b) an organoaluminum oxy compound.

(In the formula, M represents a transition metal atom of Group 4 of the periodic table,
R ¹ and R ² may be the same or different from each other and each represents a hydrocarbon group or a silicon-containing group;
m and n may be the same as or different from each other, and are integers of 1 to 3,
when m is 2 or 3, the plurality of R ¹ may be the same or different from each other;
when n is 2 or 3, the plurality of R ² may be the same or different from each other;
The types of R ¹ and R ² and the position on the cyclopentadienyl ring are the types and positions where diastereoisomers exist,
X ¹ and X ² may be the same or different from each other and each represents a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, an aryloxy group, a trialkylsilyl group, a sulfur-containing group, a halogen atom or a hydrogen atom. ,
Y represents a divalent hydrocarbon group or a divalent silicon-containing group. )