Ethylene polymerization catalyst

Abstract

To provide an ethylene polymerization catalyst that allows production, without fouling and through a simplified process, of an ethylene polymer suitable for forming a molded article having a favorable balance of processability and mechanical physical properties thereof.SOLUTION: An ethylene polymerization catalyst comprises, as constituent components, at least a metallocene complex (A), an organo-modified clay (B), and an alkylaluminum (C), wherein the metallocene complex (A) is a metallocene complex containing an ultrahigh-molecular-weight polyethylene-producing metallocene complex (A-1) and a polyethylene-producing metallocene complex (A-2) at a molar ratio (A-1) / (A-2)=1 / 100 to 45 / 100, and the organo-modified clay (B) satisfies: a) a median diameter and a mode diameter of 10-20 μm with their difference being within 5 μm, in particle size distribution by laser diffraction / scattering particle size distribution measurement; and b) proportions of particles of 5 μm or less and 33 μm or more each being 5 vol.% or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a novel ethylene polymerization catalyst, and more specifically to an ethylene polymerization catalyst which has high strength and excellent processability and is capable of producing an ethylene polymer, particularly one exhibiting a bimodal molecular weight distribution peak, using a simple apparatus. [Background technology]

[0002] Ultra-high molecular weight polyethylene has an extremely high molecular weight, equivalent to a viscosity-average molecular weight (Mv) of over 1 million, and therefore has excellent physical properties comparable to those of engineering plastics, such as excellent impact resistance, self-lubrication, abrasion resistance, weather resistance, chemical resistance, and dimensional stability. For this reason, various molding methods are being used to apply it to applications such as lining materials, food industry line parts, machine parts, artificial joints, sporting goods, and microporous membranes.

[0003] However, due to its high molecular weight, ultra-high molecular weight polyethylene has extremely low fluidity when melted, making it difficult to mold by kneading and extrusion, as is the case with ordinary polyethylene, which has a molecular weight ranging from several tens of thousands to approximately 500,000. Therefore, methods for manufacturing ultra-high molecular weight polyethylene include direct sintering of polymer powder obtained by polymerization, compression molding, molding using a ram extruder in which extrusion molding is performed while intermittently compressing the polymer, and extrusion molding in a state where the polyethylene is dispersed in a solvent or the like, followed by removal of the solvent. However, these molding methods have the drawback of being technically difficult to obtain molded articles. Furthermore, weak points are generated due to the presence of localized high-viscosity regions caused by entanglement of polymer chains and the formation of sparse areas during compression caused by insufficient fluidity of polymer particles, resulting in the obtained molded articles failing to exhibit the mechanical strength that they would otherwise possess, resulting in relatively low mechanical strength.

[0004] As a means of increasing the mechanical strength of these molded articles, ultra-high molecular weight polyethylene with a narrow molecular weight distribution, which is produced using a catalyst such as a metallocene catalyst, has been proposed. However, although the ultra-high molecular weight polyethylene obtained using a metallocene catalyst shows improved performance as a molded article, it has a high melt viscosity, and as the molecular weight increases, poor fusion occurs at the grain boundaries of the powder, meaning that the effects expected from the molecular weight cannot be fully realized, resulting in a poor balance of product properties.

[0005] As a countermeasure, a method for producing ultra-high molecular weight polyethylene has been proposed, which uses a metallocene catalyst to carry out two or more stages of sequential polymerization of ethylene, thereby making it possible to provide a molded product that has an excellent balance between processability and mechanical properties of the molded product (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-172716 [Patent Document 2] Patent Publication No. 2021-172717 Summary of the Invention [Problem to be solved by the invention]

[0007] When the multi-stage sequential polymerization proposed in Patent Documents 1 and 2 is carried out industrially, the process becomes complicated, requiring multiple reactors and a large number of connecting pipes, and this has posed problems in terms of cost and management.

[0008] Furthermore, ultra-high molecular weight polyethylene is prone to a phenomenon known as fouling, in which it adheres to the reactor walls and agitator blades during polymerization. This makes it increasingly difficult to remove the heat of reaction caused by polymerization, making it impossible to operate the reactor for extended periods of time.

[0009] The present invention has been made in view of the above problems, and provides an ethylene-based polymerization catalyst which can produce, by a simple process, an ethylene-based polymer that can provide a molded article having excellent strength and chemical resistance, as well as excellent elongation, toughness, impact resistance, and the like, and having an excellent balance between processability and the mechanical properties of the molded article, particularly an ethylene-based polymer that exhibits multi-modal peaks in molecular weight distribution, and which is less likely to cause fouling. [Means for solving the problem]

[0010] As a result of intensive studies to solve the above problems, the present inventors have found that an ethylene polymer capable of providing a molded product having an excellent balance between processability and mechanical properties can be easily produced in a single polymerization stage by using, as catalyst components, a metallocene complex suitable for producing ultra-high molecular weight polyethylene and a metallocene complex suitable for producing polyethylene in a specific ratio, and have thus completed the present invention.

[0011] Specifically, the present invention relates to an ethylene polymerization catalyst comprising, as constituent components, at least a metallocene complex (A), an organically modified clay (B), and an alkylaluminum (C), wherein the metallocene complex (A) is a metallocene complex containing a metallocene complex (A-1) for producing ultra-high molecular weight polyethylene and a metallocene complex (A-2) for producing polyethylene, in a metallocene complex (A-1) / metallocene complex (A-2) (substance ratio) of 0.01 to 0.45, and the organically modified clay (B) is an organically modified clay that satisfies the following in a particle size distribution measured by laser diffraction / scattering particle size distribution measurement: a) a median diameter and a mode diameter of 10 to 20 μm, with the difference between them being within 5 μm, and b) the proportions of particles of 5 μm or less and 33 μm or more being 5 vol % or less, respectively.

[0012] The present invention will be described in detail below.

[0013] The ethylene polymerization catalyst of the present invention belongs to the category of metallocene catalysts, which contain at least a metallocene complex (A), an organically modified clay (B), and an alkylaluminum (C) as constituent components.

[0014] Furthermore, since this enables the production of an ethylene-based polymer having a bimodal or even multimodal molecular weight distribution peak derived from the ultra-high molecular weight polyethylene component and the polyethylene component, even in a simpler production method, such as single-stage polymerization, the metallocene complex (A) is a combination of at least two components: a metallocene complex (A-1) for producing ultra-high molecular weight polyethylene and a metallocene complex (A-2) for producing polyethylene. The ratio of the metallocene complex (A-1) to the metallocene complex (A-2) is (A-1) / (A-2) (substance ratio) = 0.01 to 0.45. Here, the amount of substance is expressed in moles. If the metallocene complex (A-1) is less than 0.01, the resulting ethylene-based polymer will contain less ultra-high molecular weight polyethylene, making it difficult to achieve improved mechanical properties. On the other hand, if the ratio exceeds 0.45, the amount of ultra-high molecular weight polyethylene will be too high, causing problems with moldability and making fouling more likely to occur during the production process. In the present invention, the term "ultra-high molecular weight polyethylene" refers to polyethylene generally known as ultra-high molecular weight polyethylene having a weight average molecular weight of 1,000,000 or more, for convenience, and the term "polyethylene" refers to polyethylene generally known as general-purpose polyethylene (weight average molecular weight of approximately tens of thousands to hundreds of thousands).

[0015] The polyethylene obtained using the ethylene polymerization catalyst of the present invention is composed of a small amount of ultra-high molecular weight polyethylene and a large amount of general-purpose polyethylene, and therefore shows a bimodal molecular weight distribution curve in GPC (gel permeation chromatography), with a first peak at a molecular weight of less than 1 million and a second peak at a molecular weight of 1 million or more. However, when the proportion of ultra-high molecular weight polyethylene is particularly low, the second peak may become unclear and may appear as a shoulder peak or hump-shaped peak.

[0016] The metallocene complex (A-1) for producing ultra-high molecular weight polyethylene that constitutes the ethylene polymerization catalyst of the present invention may be any metallocene complex that can constitute a metallocene catalyst capable of producing ultra-high molecular weight polyethylene, and examples thereof include those represented by the following general formula (1):

[0017] [ka]

[0018] [In the formula, M 1 is a zirconium or hafnium atom, and X 1 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms; R 1 is a cyclopentadienyl group represented by the following general formula (2),

[0019] [ka]

[0020] (In the formula, R 4 ~R 7 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms. R 2 is a fluorenyl group represented by the following general formula (3),

[0021] [ka]

[0022] (In the formula, R 8 ~R 15 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 30 carbon atoms, an arylalkylamino group having 7 to 30 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms, and at least one of them is an alkylamino group having 1 to 20 carbon atoms or a hydrocarbon group having 4 to 20 carbon atoms and a quaternary carbon atom. R 3 is R represented by the following general formula (4) or the following general formula (5): 1 and R 2 is a crosslinking unit of

[0023] [ka]

[0024] [ka]

[0025] (In the formula, R 16 ~R 17 and R 18 ~R 19 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 30 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms; M 2 is a silicon atom, a germanium atom, or a tin atom. l is a natural number between 1 and 5.]

[0026] The metallocene complex (A-1) is a metallocene compound represented by the above general formula (1), and R 1 and a cyclopentadienyl group R 2 M is a fluorenyl group 1 The structure sandwiches the R 3 By R 1 and R 2 It has a structure in which the above is cross-linked.

[0027] where M 1 is a zirconium atom or a hafnium atom, and by using these specific metal atoms, it becomes possible to produce ultra-high molecular weight polyethylene with high production efficiency.

[0028] X 1 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 30 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms, and these specific substituents make it possible to produce polyethylene with an extremely high molecular weight. 1 Specific examples of the alkyl group include a hydrogen atom, a halogen atom such as a chlorine atom, a bromine atom, or an iodine atom; an alkyl group having 1 to 30 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and isomeric substituents thereof; an aryl group having 6 to 30 carbon atoms such as a phenyl group, an indenyl group, a naphthyl group, a fluorenyl group, or a biphenylenyl group; an arylalkyl group having 7 to 30 carbon atoms such as a benzyl group, a phenylethyl group, a diphenylmethyl group, or a diphenylethyl group; an alkylaryl group having 7 to 30 carbon atoms such as a methylphenyl group, an ethylphenyl group, or a methylnaphthyl group; an alkylsilyl group such as a trimethylsilyl group; and an alkylamino group such as an N,N-dimethylamino group or an N,N-diethylamino group.

[0029] R 1 is a cyclopentadienyl group represented by the above general formula (2), and R4 ~R 7 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms, and by using these specific substituents, it becomes possible to efficiently produce polyethylene with an extremely high molecular weight. 4 ~R 7 Specific examples of X 1 Examples similar to those of R 1 Specific examples of the cyclopentadienyl group include a cyclopentadienyl group, a methylcyclopentadienyl group, an ethylcyclopentadienyl group, an n-butyl-cyclopentadienyl group, a dimethylcyclopentadienyl group, a diethylcyclopentadienyl group, a methoxycyclopentadienyl group, an N,N-dimethylaminocyclopentadienyl group, and a trimethylsilylcyclopentadienyl group.

[0030] R 2 is a fluorenyl group represented by the above general formula (3), and R 8 ~R 15 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 30 carbon atoms, an arylalkylamino group having 7 to 30 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms, at least one of which is an alkylamino group having 1 to 20 carbon atoms or a hydrocarbon group having 4 to 20 carbon atoms and a quaternary carbon atom. 3 By having a substituent of an alkylamino group having 1 to 20 carbon atoms or a hydrocarbon group having 4 to 20 carbon atoms and a quaternary carbon atom on the fluorenyl group represented by the formula (R), the metallocene complex (A-1) becomes a complex capable of producing ultra-high molecular weight polyethylene. 8 ~R 15Specific examples of R 4 ~R 7 Examples similar to those of R 2 Specific examples of the fluorenyl group include a 2-tert-butyl-9-fluorenyl group, a 2,7-di-tert-butyl-9-fluorenyl group, a 2-(3,3-dimethylpropyl)-9-fluorenyl group, a 2,7-di-(3,3-dimethylpropyl)-9-fluorenyl group, a 2-methyl-7-tert-butyl-9-fluorenyl group, a 2-ethyl-7-tert-butyl-9-fluorenyl group, a 2-methoxy-7-tert-butyl-9-fluorenyl group, and a 2-ethoxy-7-tert-butyl-9-fluorenyl group. Examples include a tert-butyl-9-fluorenyl group, a 2-N,N-dimethylamino-9-fluorenyl group, a 2-N,N-diethylamino-9-fluorenyl group, a 2-N,N-dimethylamino-7-tert-butyl-9-fluorenyl group, a 2-N,N-diethylamino-7-tert-butyl-9-fluorenyl group, a 2,7-bis(N,N-dimethylamino)-9-fluorenyl group, and a 2,7-bis(N,N-diethylamino)-9-fluorenyl group.

[0031] R 3 is the R 1 and the R 2 is a crosslinking unit represented by the general formula (4) or the general formula (5), and R 16 ~R 17 and R 18 ~R 19 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 30 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms, and these specific substituents make it possible to produce polyethylene with a high molecular weight. 16 ~R 17 and R 18 ~R 19 As a specific example of the above, the X 1 Examples similar to those given above can be mentioned.

[0032] And l is a natural number between 1 and 5.

[0033] Specific examples of the metallocene complex (A-1) include isopropyl(cyclopentadienyl)(2-tert-butyl-9-fluorenyl)zirconium dichloride, isopropyl(cyclopentadienyl)(2,7-di(tert-butyl)-9-fluorenyl)zirconium dichloride, isopropyl(cyclopentadienyl)(2-N,N-dimethylamino-9-fluorenyl)zirconium dichloride, and isopropyl(cyclopentadienyl)(2-tert-butyl-9-fluorenyl)zirconium dichloride. iso-propyl(cyclopentadienyl)(2-methyl-7-N,N-dimethylamino-9-fluorenyl)zirconium dichloride, iso-propyl(cyclopentadienyl)(2-methoxy-7-N,N-dimethylamino-9-fluorenyl)zirconium dichloride, iso-propyl(cyclopentadienyl)(2-methyl-7-tert-butyl)zirconium dichloride butyl-9-fluorenyl)zirconium dichloride, iso-propyl(cyclopentadienyl)(2-methoxy-7-tert-butyl-9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2-tert-butyl-9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2,7-di(tert-butyl)-9-fluorenyl)zirconium dichloride, diphenylmethylene( cyclopentadienyl)(2-N,N-dimethylamino-9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2,7-bis((N,N-dimethyl)amino)-9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2-methyl-7-N,N-dimethylamino-9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2-methoxy-7-N,Examples include zirconium compounds such as N-dimethylamino-9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2-methyl-7-tert-butyl-9-fluorenyl)zirconium dichloride, and diphenylmethylene(cyclopentadienyl)(2-methoxy-7-tert-butyl-9-fluorenyl)zirconium dichloride, complexes in which the zirconium atom is replaced with a hafnium atom, and compounds in which the dichloro form of the above metallocene complex is replaced with a dibromo form, diiodo form, dimethyl form, diethyl form, dimethoxy form, dihydro form, diphenyl form, or dibenzyl form.

[0034] The metallocene complex (A-2) for producing polyethylene that constitutes the ethylene polymerization catalyst of the present invention may be any metallocene complex that constitutes a metallocene catalyst capable of producing polyethylene, and examples thereof include those represented by the following general formula (6) or (7):

[0035] [ka]

[0036] [ka]

[0037] [In the formula, M 3 and M 4 is a titanium atom, a zirconium atom, or a hafnium atom, and X 2 and X 3 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms; R 20 and R 23 is a cyclopentadienyl group represented by the following general formula (8) or an indenyl group represented by the following general formula (9),

[0038] [ka]

[0039] [ka]

[0040] (In the formula, R 25 ~R 28 and R 29 ~R 34 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms. R 21 and R 24 are each independently a cyclopentadienyl group, an indenyl group, or a fluorenyl group represented by the following general formulas (10) to (12),

[0041] [ka]

[0042] [ka]

[0043] (In the formula, R 35 ~R 38 and R 39 ~R 44 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms.

[0044] [ka]

[0045] (In the formula, R 45 ~R 52 are each independently a hydrogen atom, a halogen atom, an alkoxy group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms (excluding hydrocarbon groups having 4 to 20 carbon atoms and a quaternary carbon atom), or a trialkylsilylalkylene group having 4 to 20 carbon atoms). R 22 is R represented by the following general formula (13) or the following general formula (14): 20 and R 21 is a crosslinking unit of

[0046] [ka]

[0047] [ka]

[0048] (In the formula, R 53 ~R 54 and R 55 ~R 56 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 30 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms; M 5 is a silicon atom, a germanium atom, or a tin atom. m is a natural number between 1 and 5.

[0049] The metallocene complex (A-2) is a metallocene compound represented by the above general formula (6) or (7), and R20 and R 21 At M 3 Sandwich and then R 22 By R 20 and R 21 or R 23 and R 24 At M 4 Some have a sandwich structure.

[0050] where M 3 and M 4 are each independently a titanium atom, a zirconium atom, or a hafnium atom.

[0051] X 2 and X 3 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 30 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms, and these specific substituents make it possible to produce polyethylene. 2 or X 3 Specific examples of the alkyl group include a hydrogen atom, a halogen atom such as a chlorine atom, a bromine atom, or an iodine atom; an alkyl group having 1 to 30 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and isomeric substituents thereof; an aryl group having 6 to 30 carbon atoms such as a phenyl group, an indenyl group, a naphthyl group, a fluorenyl group, or a biphenylenyl group; an arylalkyl group having 7 to 30 carbon atoms such as a benzyl group, a phenylethyl group, a diphenylmethyl group, or a diphenylethyl group; an alkylaryl group having 7 to 30 carbon atoms such as a methylphenyl group, an ethylphenyl group, or a methylnaphthyl group; an alkylsilyl group such as a trimethylsilyl group; and an alkylamino group such as an N,N-dimethylamino group or an N,N-diethylamino group.

[0052] R 20 and R 23are each independently a cyclopentadienyl group or an indenyl group represented by the above general formula (8) or (9), and R 25 ~R 28 and R 29 ~R 34 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms, and by being these specific substituents, polyethylene can be produced efficiently. 25 ~R 28 and R 29 ~R 34 Specific examples of R include a hydrogen atom, a halogen atom such as a chlorine atom, a bromine atom, or an iodine atom; an alkyl group having 1 to 30 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, or an isomeric substituent thereof; an aryl group having 6 to 30 carbon atoms such as a phenyl group, an indenyl group, a naphthyl group, a fluorenyl group, or a biphenylenyl group; an arylalkyl group having 7 to 30 carbon atoms such as a benzyl group, a phenylethyl group, a diphenylmethyl group, or a diphenylethyl group; an alkylaryl group having 7 to 30 carbon atoms such as a methylphenyl group, an ethylphenyl group, or a methylnaphthyl group; and an alkylsilyl group such as a trimethylsilyl group. 20 and R 23 Specific examples of the alkyl group include a cyclopentadienyl group, a methylcyclopentadienyl group, an ethylcyclopentadienyl group, an n-butyl-cyclopentadienyl group, a dimethylcyclopentadienyl group, a diethylcyclopentadienyl group, a methoxycyclopentadienyl group, a trimethylsilylcyclopentadienyl group, an indenyl group, a methylindenyl group, an ethylindenyl group, a dimethylindenyl group, a methoxyindenyl group, an ethoxyindenyl group, and a trimethylsilylindenyl group.

[0053] R 21 and R 24are each independently a cyclopentadienyl group, an indenyl group, or a fluorenyl group represented by the above general formulas (10) to (12), and R 35 ~R 38 and R 39 ~R 44 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms; R 45 ~R 52 are each independently a hydrogen atom, a halogen atom, an alkoxy group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms (excluding hydrocarbon groups having 4 to 20 carbon atoms and a quaternary carbon atom), or a trialkylsilylalkylene group having 4 to 20 carbon atoms. By having these substituents, the metallocene complex (A-2) becomes a complex capable of producing ordinary polyethylene with high activity, without producing ultra-high molecular weight polyethylene as in the case of the metallocene complex (A-1). 35 ~R 38 , R 39 ~R 44 and R 45 ~R 52 Specific examples of R 25 ~R 28 and R 29 ~R 34 The same examples as those of 45 ~R 52 With regard to R, hydrocarbon groups having 1 to 20 carbon atoms and hydrocarbon groups having 4 to 20 carbon atoms and a quaternary carbon atom are excluded. 21 and R 24Specific examples of R include a cyclopentadienyl group, a methylcyclopentadienyl group, an ethylcyclopentadienyl group, an n-butylcyclopentadienyl group, a dimethylcyclopentadienyl group, a diethylcyclopentadienyl group, a methoxycyclopentadienyl group, a trimethylsilylcyclopentadienyl group, an indenyl group, a methylindenyl group, an ethylindenyl group, a dimethylindenyl group, a methoxyindenyl group, an ethoxyindenyl group, and a trimethylsilylindenyl group. 24 Specific examples of the alkyl group include an indenyl group, a methylindenyl group, an ethylindenyl group, a dimethylindenyl group, a methoxyindenyl group, an ethoxyindenyl group, a trimethylsilylindenyl group, a fluorenyl group, a methylfluorenyl group, an ethylfluorenyl group, a dimethylfluorenyl group, a methoxyfluorenyl group, and a trimethylsilylfluorenyl group.

[0054] R 22 is the R 20 and the R 21 is a crosslinking unit represented by the general formula (13) or (14), and R 53 ~R 54 and R 55 ~R 56 are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 30 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms, and these specific substituents make it possible to produce polyethylene. 53 ~R 54 and R 55 ~R 55 As a specific example of the above, the X 2 Or X 3 Examples similar to those given above can be mentioned.

[0055] And m is a natural number between 1 and 5.

[0056] Specific examples of the metallocene complex (A-2) include dicyclopentadienyl zirconium dichloride, iso-propyl(dicyclopentadienyl)zirconium dichloride, dimethylsilylene(dicyclopentadienyl)zirconium dichloride, iso-propyl(dicyclopentadienyl)dichloride, diphenylmethylenedicyclopentadienyl zirconium dichloride, diphenylmethylenedicyclopentadienyl zirconium dichloride, bisindenyl zirconium dichloride, ethylenebisindenyl zirconium dichloride, iso-propyl(cyclopentadienyl)(indenyl)dichloride, iso-propyl(cyclopentadienyl)(fluorenyl)dichloride, iso-propyl(cyclopentadienyl)(2-methylfluorenyl)dichloride, iso-propyl(cyclopentadienyl)(2, Examples of suitable ethylene compounds include zirconium compounds such as diphenylmethylene(cyclopentadienyl)(indenyl) dichloride, diphenylmethylene(cyclopentadienyl)(fluorenyl) dichloride, diphenylmethylene(cyclopentadienyl)(2-methylfluorenyl) dichloride, and diphenylmethylene(cyclopentadienyl)(2,7-dimethylfluorenyl) dichloride; compounds in which the zirconium atom is replaced with a titanium atom or a hafnium atom; and compounds in which the dichloro form of the above metallocene compounds is replaced with a dibromo form, a diiodo form, a dimethyl form, a diethyl form, a dimethoxy form, a dihydro form, a diphenyl form, or a dibenzyl form. Of these, zirconium compounds and hafnium compounds are preferred because they serve as ethylene polymerization catalysts that can efficiently produce ethylene polymers.

[0057] Two or more types of the metallocene complex (A-1) and two or more types of the metallocene complex (A-2) may be used, and two or more types of each may be used.Furthermore, the metallocene complex may contain an additional metallocene complex.

[0058] The organically modified clay (B) constituting the ethylene polymerization catalyst of the present invention is a clay modified with a tertiary ammonium ion represented by the following general formula (15), and satisfies the following requirements in the particle size distribution measured by laser diffraction / scattering particle size distribution measurement: a) the median diameter and mode diameter are 10 to 20 μm, with the difference between them being within 5 μm, and b) the proportions of particles of 5 μm or less and 33 μm or more are each 5 vol % or less.

[0059] [ka]

[0060] Here, R in the above general formula (15) 57 , R 58 , R 59 are each independently a saturated alkyl group having 1 to 30 carbon atoms, an unsaturated alkyl group having 2 to 30 carbon atoms, an alkylalkoxy group having 1 to 30 carbon atoms, an alkylamino group having 1 to 30 carbon atoms, an alkylsilyl group having 1 to 30 carbon atoms, an alkoxyalkylene group having 2 to 30 carbon atoms, a dialkylaminoalkylene group having 3 to 30 carbon atoms, or a trialkylsilylalkylene group having 4 to 30 carbon atoms, and R 1 , R 2 , R 3 At least one of R is an alkyl group having 10 or more carbon atoms, and as long as the alkyl group has 10 or more carbon atoms, the alkyl group may be a saturated alkyl group or an unsaturated alkyl group. 1 , R 2 , R 3 If any of the above is an alkyl group having less than 10 carbon atoms or a substituent other than an alkyl group, it becomes difficult to efficiently produce polymer particles, such as ethylene-based polymer particles, with a catalyst using the obtained organomodified clay as an activator, and the organomodified clay has problems as a polymerization catalyst activator.

[0061] And R 57 , R 58 , R 59Specific examples of the alkyl group include saturated alkyl groups having 1 to 30 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an aryl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a 2-methylbutyl group, a 1-methylbutyl group, a 1-ethylpropyl group, a neopentyl group, a tert-pentyl group, an n-hexyl group, a decyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, an octadecyl group, and a behenyl group; unsaturated alkyl groups having 2 to 30 carbon atoms, such as a palymitoleyl group, an oleyl group, a linoleyl group, an elaidolinoleyl group, a linolenyl group, an elaidolinolenyl group, and an erucyl group; and unsaturated alkyl groups having 2 to 30 carbon atoms, such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and an isopropoxy group. alkylamino groups having 1 to 30 carbon atoms, such as a dimethylamino group, a diethylamino group, a dipropylamino group, a dibutylamino group, or a diisopropylamino group; alkylsilyl groups having 1 to 30 carbon atoms, such as a trimethylsilyl group, a tri-tert-butylsilyl group, a di-tert-butylmethylsilyl group, or a tert-butyldimethylsilyl group; alkoxyalkylene groups having 2 to 30 carbon atoms, such as a methoxymethylene group or an ethoxymethylene group; dialkylaminoalkylene groups having 3 to 30 carbon atoms, such as a dimethylaminomethylene group or a diethylaminomethylene group; and trialkylsilylalkylene groups having 4 to 20 carbon atoms, such as a trimethylsilylmethylene group or a tert-butyldimethylsilylmethylene group.

[0062] Applicable R 57 , R 58 , R 59 At least one of the substituents is an alkyl group having 10 or more carbon atoms, such as a decyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, an octadecyl group, an oleyl group, or a behenyl group.

[0063] Specific examples of the organic aliphatic group include aliphatic ammonium groups such as an N,N-dimethyl-behenylammonium group, an N-methyl-N-ethyl-behenylammonium group, an N-methyl-Nn-propyl-behenylammonium group, an N,N-dioleyl-methylammonium group, an N,N-dimethyl-behenylammonium group, an N-methyl-N-ethyl-behenylammonium group, an N-methyl-Nn-propyl-behenylammonium group, and an N,N-dioleyl-methylammonium group; and aliphatic phosphonium groups such as a P,P-dimethyl-behenylphosphonium group, a P,P-diethyl-behenylphosphonium group, a P,P-dipropyl-behenylphosphonium group, a P,P-dimethyl-behenylphosphonium group, a P,P-diethyl-behenylphosphonium group, and a P,P-dipropyl-behenylphosphonium group.

[0064] The clay in the organically modified clay (B) constituting the ethylene polymerization catalyst of the present invention may be any clay as long as it belongs to the category of clay, and may be a clay mineral. Generally, clay is formed by stacking many layers called silicate layers, which are composed of a tetrahedral sheet in which silica tetrahedra are continuous two-dimensionally and an octahedral sheet in which alumina octahedra, magnesia octahedra, etc. are continuous two-dimensionally in a ratio of 1:1 or 2:1. Si in some of the silica tetrahedra is replaced by Al, Al in the alumina octahedra by Mg, and Mg in the magnesia octahedra by Li, etc., resulting in a lack of positive charge within the layers, and the layers as a whole are negatively charged. In order to compensate for this negative charge, Na is introduced between the layers. + Ya Ca 2+ The clay is known to contain cations such as kaolinite, talc, smectite, vermiculite, mica, brittle mica, and mercury, both natural and synthetic, and these can be used, with smectite being preferred due to its ease of availability and ease of organic modification, and hectorite or montmorillonite being even more preferred among smectites.

[0065] The organically modified clay (B) constituting the ethylene polymerization catalyst of the present invention can be obtained by modifying clay with a tertiary ammonium salt represented by the following structural formula (16).

[0066] [ka]

[0067] Here, 57 , R 58 , R 59 is the same as above, and the same examples can be given. [A] - is an anion, and may be any anion as long as it belongs to the category of anions, such as fluoride ion, chloride ion, bromide ion, iodide ion, sulfate ion, nitrate ion, phosphate ion, perchlorate ion, oxalate ion, citrate ion, succinate ion, tetrafluoroborate ion, or hexafluorophosphate ion.

[0068] Specific examples of the organic aliphatic salts include aliphatic amine salts such as N,N-dimethyl-behenylamine hydrochloride, N-methyl-N-ethyl-behenylamine hydrochloride, N-methyl-Nn-propyl-behenylamine hydrochloride, N,N-dioleyl-methylamine hydrochloride, N,N-dimethyl-behenylamine sulfate, N-methyl-N-ethyl-behenylamine sulfate, N-methyl-Nn-propyl-behenylamine sulfate, and N,N-dioleyl-methylamine sulfate; and aliphatic phosphine salts such as P,P-dimethyl-behenylphosphine hydrochloride, P,P-diethyl-behenylphosphine hydrochloride, P,P-dipropyl-behenylphosphine hydrochloride, P,P-dimethyl-behenylphosphine sulfate, P,P-diethyl-behenylphosphine sulfate, and P,P-dipropyl-behenylphosphine sulfate.

[0069] The organically modified clay (B) of the present invention can be obtained by introducing organic aliphatic groups between clay layers to form an ionic complex. When preparing the organically modified clay (B), it is preferable to select conditions for a clay concentration of 0.1 to 30% by weight and a treatment temperature of 0 to 100°C. The organic aliphatic salt may be prepared as a solid and dissolved in a solvent for use, or a solution of the organic aliphatic salt may be prepared by chemical reaction in a solvent and used as is. The reaction ratio of the clay to the organic aliphatic salt is optional, but a ratio of 0.5 to 1.5 mol of the organic aliphatic salt per 1 kg of clay is preferred, as this allows for efficient organic modification. Examples of reaction solvents that can be used in the modification include aliphatic hydrocarbons such as pentane, hexane, and heptane; aromatic hydrocarbons such as benzene and toluene; alcohols such as ethyl alcohol and methyl alcohol; ethers such as ethyl ether and n-butyl ether; halogenated hydrocarbons such as methylene chloride and chloroform; acetone; 1,4-dioxane; tetrahydrofuran; and water. It is preferable to use alcohols or water alone or as one of the solvent components.

[0070] The organically modified clay (B) constituting the ethylene polymerization catalyst of the present invention satisfies the following characteristics: a) a median diameter and a mode diameter of 10 to 20 μm, with the difference between them being within 5 μm; and b) the proportion of particles of 5 μm or less and 33 μm or more in the particle size distribution being 5% by volume or less, respectively. Here, the median diameter and mode diameter can be determined by measuring the particle size distribution using, for example, a laser diffraction / scattering particle size analyzer. A solvent may be used or not. If a solvent is used, lower alcohols are preferred from the viewpoint of dispersibility of the organically modified clay, and ethanol or 2-propanol is more preferred from the viewpoints of availability and ease of handling. The median diameter refers to the 50% by volume cumulative diameter and is sometimes referred to as the median diameter. The mode diameter is the particle size at the peak of the particle size distribution and is sometimes referred to as the most frequent diameter. Although the definitions of the median diameter and the mode diameter are different, the closer the particle size distribution approaches a lognormal distribution, the more closely they resemble each other. Therefore, the organically modified clay of the present invention, which satisfies the requirements of a) a median diameter and a mode diameter of 10 to 20 μm, with a difference within 5 μm, exhibits a particle size distribution approximating a log-normal distribution. Furthermore, by satisfying the requirements of b) the proportion of particles of 5 μm or less and 33 μm or more in the particle size distribution being 5 volume % or less, respectively, the proportion of fine particles and coarse particles is low. Thus, the organically modified clay (B) exhibits a narrow particle size distribution approximating a log-normal distribution. Here, when the organically modified clay is used as an activator for a polymerization catalyst, particularly a single-site catalyst, especially a metallocene catalyst, its activity tends to be inversely proportional to the particle size of the organically modified clay. Therefore, in terms of high activity, it is preferable to reduce the particle size. However, on the other hand, the particle size of polymer particles, such as ethylene polymer powder produced from the catalyst, is proportional to the particle size of the organically modified clay and proportional to the cube root of the catalytic activity. Therefore, the smaller the particle size of the organically modified clay, the smaller the particle size of the polymer particles. This makes it more likely for the particles to adhere due to static electricity, making them less likely to fall out of silos or hoppers used during processing, and may also cause fouling during polymerization, making it impossible to control the polymerization reaction.On the other hand, if the particle size of the organically modified clay is increased, not only will the activity decrease, but the organically modified clay remaining in the polymer particles may clog the filter of the processing machine, making it impossible to operate the processing machine for a long period of time. The organically modified clay (B) constituting the ethylene polymerization catalyst of the present invention has a) median diameter and mode diameter of 10 to 20 μm, with the difference between them being within 5 μm, and b) the proportions of particles of 5 μm or less and 33 μm or more in the particle size distribution are each 5 vol% or less, so when used as an activator for a polymerization catalyst, these problems are resolved, and the organically modified clay (B) is useful as an activator for a polymerization catalyst, enabling the production of polymer particles that do not adhere due to static electricity or clog the filter of the processing machine.

[0071] There are no particular limitations on the method for producing the organically modified clay (B) in terms of the method for adjusting its particle size and particle size distribution, and it can be prepared by grinding, granulation, classification, etc., alone or in combination. The grinding method is also not particularly limited, and it is preferable to use so-called fine grinders such as jet mills, bead mills, vibration ball mills, and planetary mills, which are capable of grinding to a few μm. Jet mills are more preferred because they do not deteriorate the organically modified clay due to heat generated during grinding and allow for continuous grinding. There are also no particular limitations on the granulation method, and spray drying is preferred because it allows for large-scale granulation in a short period of time. Spray drying involves spraying a solution, sol, slurry, etc. and drying it with hot air to obtain particles. There are no particular limitations on the spraying method, and it is preferable to use a rotary atomizer, two-fluid nozzle, or four-fluid nozzle in order to produce fine droplets. The sol obtained by dispersing clay in water becomes increasingly sol-like over time, losing fluidity and making it impossible to transfer. Therefore, it is preferable to add 1 to 10 parts by weight of an anti-gelling agent such as sodium pyrophosphate or tetrasodium etidronate per 100 parts by weight of clay. Furthermore, there are no particular limitations on the classification method; from the perspective of classification accuracy, it is preferable to use a gravity classifier, inertia classifier, centrifugal classifier, or air classifier. Particle size adjustment can be performed before or after organic modification of the clay. It is particularly efficient to adjust the particle size after modification, as this reduces the effect of increasing the particle size of the clay during modification.

[0072] The alkylaluminum (C) constituting the ethylene polymerization catalyst of the present invention may be any compound that falls within the category generally called alkylaluminum. Among these, alkylaluminums represented by the following general formula (17) are preferred, since they are ethylene polymerization catalysts that can efficiently produce ethylene polymer particles:

[0073] [ka]

[0074] (In the formula, R 62 is a hydrocarbon group having 1 to 20 carbon atoms, and R 63 and R 64 are each independently a hydrocarbon group having 1 to 20 carbon atoms, a hydrogen atom, or a chlorine atom. R 62 ~R 64 Examples of the hydrocarbon group having 1 to 20 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and a tert-butyl group. Examples of the alkylaluminum (C) include trimethylaluminum, triethylaluminum, and triisobutylaluminum, which are particularly suitable for easily alkylating the metallocene complex.

[0075] In the ethylene polymerization catalyst of the present invention, the metallocene complex (A) comprises at least a metallocene complex (A-1) for producing ultra-high molecular weight polyethylene and a metallocene complex (A-2) for producing polyethylene, and the ratio of the metallocene complex (A-1) / metallocene complex (A-2) (mass ratio) is 1 / 100 to 45 / 100. There are no limitations on the ratios of the metallocene complex (A), the organically modified clay (B), and the alkylaluminum (C) used when preparing the ethylene polymerization catalyst of the present invention. In particular, the ratio of the metallocene complex (A) to the organically modified clay (B) is preferably (A):(B)=0.001 (mol):1 (kg) to 1 (mol):1 (kg), particularly preferably 0.01 (mol):1 (kg) to 0.1 (mol):1 (kg), because this allows for efficient production of ethylene polymers. The molar ratio of the alkyl aluminum (C) to the metallocene complex (A) is preferably in the range of (C) / (A)=0.01-100,000, and particularly preferably in the range of 1-100.

[0076] The ethylene polymerization catalyst of the present invention can be prepared by any method that allows preparation from at least a metallocene complex (A-1) for producing ultra-high molecular weight polyethylene, a metallocene complex (A-2) for producing polyethylene, an organically modified clay (B), and an alkylaluminum (C). For example, a method can be used in which the metallocene complex (A), the organically modified clay (B), and the alkylaluminum (C) are mixed using a solvent inert to them. There is no restriction on the order in which these components are reacted and mixed. Since this results in particularly excellent polymerization activity, it is preferable to contact the organically modified clay (B) with the alkylaluminum (C) first, and then the metallocene complex (A). There are no restrictions on the temperature or duration of this treatment. It is also possible to prepare an ethylene polymerization catalyst using two or more types of each of the metallocene complex (A), the organically modified clay (B), and the alkylaluminum (C).

[0077] The ethylene polymerization catalyst of the present invention can be used not only for homopolymerization of ethylene but also for copolymerization with other α-olefins such as propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene, and the ethylene polymer obtained by these polymerizations is used in the sense of including not only homopolymers but also copolymers.

[0078] Examples of methods for producing ethylene polymers include slurry polymerization, solution polymerization, and gas-phase polymerization. The solvent used in slurry polymerization or solution polymerization may be any commonly used organic solvent, such as benzene, toluene, xylene, pentane, hexane, or heptane. Olefins such as propylene, 1-butene, 1-octene, or 1-hexene can also be used as the solvent. The polymerization conditions, such as the polymerization temperature, polymerization time, polymerization pressure, and monomer concentration, can be selected arbitrarily. Among these, the polymerization temperature of 30 to 90°C, the polymerization time of 10 seconds to 20 hours, and the polymerization pressure of normal pressure to 100 MPa are preferred, as they enable efficient production of ethylene polymers. Furthermore, molecular weight can be adjusted using hydrogen or the like during polymerization. Polymerization can be carried out in any of batch, semi-continuous, and continuous modes. The ethylene polymer obtained after polymerization can be separated and recovered as particles from the polymerization solvent by a conventional method and dried. [Effects of the Invention]

[0079] The ethylene polymerization catalyst of the present invention makes it possible to produce, by a simple process, an ethylene polymer that can be molded into a molded article having an excellent balance between processability and mechanical properties of the molded article. [Example]

[0080] The present invention will be described in more detail below by showing examples, but the present invention is not limited to these examples.

[0081] In the examples, an airflow mill (manufactured by Nisshin Engineering, product name SJ-1500CB) was used for pulverization, and an airflow classifier (manufactured by Nisshin Engineering, product name TC-25) was used for classification. Particle size was adjusted by adjusting the air pressure and supply rate for pulverization, and by adjusting the rotation speed for classification. The physical properties were measured by the following methods.

[0082] -Measurement of intrinsic viscosity- Measurement was carried out using an Ubbelohde viscometer at 135° C. with decalin as a solvent and an ethylene polymer concentration of 0.005 wt %.

[0083] -Particle size measurement- A laser diffraction / scattering particle size distribution analyzer (manufactured by Microtrack Bell, product name MT-3300) was used, and 2-propanol was used as the solvent.

[0084] -Molecular weight measurement- A GPC system (Tosoh Corporation, product name HLC-8121GPC / HT) and a column (Tosoh Corporation, product name TSKgel GMHhr-H(20)HT) were used, with the column temperature set to 140°C and 1,2,4-trichlorobenzene used as the eluent. The measurement sample was prepared at a concentration of 1.0 mg / ml, and 0.3 ml was injected for measurement. The molecular weight calibration curve was calibrated using a polystyrene sample with a known molecular weight. The weight-average molecular weight (Mw) was calculated as a linear polyethylene equivalent value.

[0085] -Measurement of tensile breaking stress and nominal tensile breaking strain- The ethylene polymer was filled into a 150 mm × 150 mm metal frame, sandwiched between polyethylene terephthalate films, preheated at 190°C for 5 minutes, and then heated and compressed at 190°C and a press pressure of 20 MPa. After that, the mold temperature was 120°C and the mixture was cooled for 10 minutes to obtain a pressed sheet with a thickness of 8 mm.

[0086] Using test pieces cut out from this sheet, the tensile stress at break and the nominal tensile strain at break were measured using a tensile testing machine (manufactured by A&D Co., Ltd., product name Tensilon RTG-1210) according to the method of JIS K 6922-2 (2005).

[0087] -Measurement of Izod impact strength- Compression molded specimens were molded in the same way as for the tensile stress at break and nominal tensile strain at break, and then cut to a length of 63.5 mm, width of 12.7 mm, and thickness of 6.35 mm. Test specimens were then post-processed with double notches (razor notches, notch spacing 3.56 mm). Using these specimens, double-notched Izod impact strength was measured at a hammer capacity of 4 J and a temperature of 23°C in accordance with ASTM D256.

[0088] Manufacturing Example 1 A 5-liter stainless steel beaker was charged with 1800 ml of water, 1800 ml of ethanol (trade name: Equinene F-3, manufactured by Japan Alcohol Sales Co., Ltd.), and 226.8 g of N,N-dimethyloctadecylamine (trade name: Lipomin DM18D, manufactured by Lion Specialty Chemicals Co., Ltd.), and 80.7 ml of hydrochloric acid (special grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was slowly added with stirring. The mixture was heated to 60°C. 600 g of synthetic hectorite (trade name: Laponite RD, manufactured by BYK Japan KK) was added in dry equivalent, and stirring was continued for 1 hour while maintaining the temperature at 60°C. The obtained slurry was filtered, dried at 85°C for 24 hours, and then crushed and classified to obtain 187.5 g of organically modified clay (B-1) with a median diameter of 13.4 μm, a mode diameter of 14.3 μm, a ratio of 5 μm or less of 3.2 vol.%, and a ratio of 33 μm or more of 1.4 vol.%.

[0089] Manufacturing Examples 2 to 5 Except for adjusting the conditions for pulverization and classification, the organically modified clays (B-2) to (B-5) were obtained in the same manner as in Production Example 1. Details are shown in Table 1.

[0090] Manufacturing Example 6 A 5-liter stainless steel beaker was charged with 1800 ml of water, 1800 ml of ethanol, and 319.2 g of N,N-dioleylmethylamine (Lipomin MO, manufactured by Lion Specialty Chemicals). 63.7 ml of hydrochloric acid was slowly added while stirring, and the mixture was heated to 60 °C. 600 g of synthetic hectorite (dry equivalent) was added, and stirring was continued for 1 hour while maintaining the temperature at 60 °C. The resulting slurry was filtered, dried at 85 °C for 24 hours, and then crushed and classified to obtain 190.5 g of organically modified clay (B-6). The clay had a median diameter of 10.5 μm, a mode diameter of 11.0 μm, and a ratio of particles smaller than 5 μm (4.8 vol.%) and larger than 33 μm (0.1 vol.%).

[0091] Manufacturing Example 7 A 5-liter stainless steel beaker was charged with 1800 ml of water, 1800 ml of ethanol, and 259.5 g of N,N-dimethylbehenylamine (Lipomin DM22D, manufactured by Lion Specialty Chemicals). 80.7 ml of hydrochloric acid was slowly added while stirring, and the mixture was heated to 60 °C. 600 g of dry montmorillonite (Kunimine Industries Co., Ltd., Kunipia-F) was added, and the mixture was stirred for 1 hour while maintaining the temperature at 60 °C. The resulting slurry was filtered, dried at 85 °C for 24 hours, and then crushed and classified to obtain 223.3 g of organically modified clay (B-7). The clay had a median diameter of 19.7 μm, a mode diameter of 18.5 μm, a ratio of particles smaller than 5 μm by volume of 1.7 vol%, and a ratio of particles larger than 33 μm by volume of 4.9 vol%.

[0092] [Table 1]

[0093] Example 1 A 300 ml flask equipped with a thermometer and a reflux condenser was purged with nitrogen, and then charged with 20.0 g of the organically modified clay (B-1) obtained in Production Example 1 and 87 ml of n-hexane (Wako Pure Chemical Industries, special grade). 50.2 mg (80 μmol) of diphenylmethylene(cyclopentadienyl)(2-dimethylamino-9-fluorenyl)zirconium dichloride (molecular weight: 627.8) synthesized by a known method was added as the metallocene complex (A-1) for producing ultra-high molecular weight polyethylene. 291.3 mg (720 μmol) of bis(n-butylcyclopentadienyl)zirconium dichloride (Fujifilm Wako Chemical, molecular weight: 404.5) was added as the metallocene complex (A-2) for producing polyethylene, and 114 ml of a hexane solution of 20% triisobutylaluminum was added, and the mixture was stirred at 60°C for 3 hours. After standing for 1 hour, the supernatant was removed and the mixture was washed twice with 174 ml of n-hexane. Then, 166 ml of n-hexane and 8 ml of a hexane solution of 20% triisobutylaluminum (manufactured by Tosoh Finechem Corporation) were added to obtain a suspension of an ethylene polymerization catalyst ((A-1) / (A-2)=0.111).

[0094] A 10-liter autoclave was purged with nitrogen and charged with 6 liters of n-hexane, 5.5 ml of a 20% triisobutylaluminum hexane solution, and 200 mg of the ethylene polymerization catalyst suspension (solids content equivalent). While maintaining the temperature inside the autoclave at 60°C, ethylene and hydrogen were continuously supplied to the autoclave so that the ethylene partial pressure was 0.87 MPa and the hydrogen concentration in the gas phase was 200 ppm, resulting in a slurry polymerization of ethylene. After 180 minutes, the pressure was released and the system was cooled. The slurry was filtered and dried, yielding 1028 g of particulate ethylene polymer (activity 5140 g / g catalyst). No adhesion of the ethylene polymer to the reactor walls or stirring blades was observed.

[0095] The resulting ethylene polymer had an intrinsic viscosity of 4.7 dl / g, Mw of 330,000, and Mw / Mn of 4.4. The molecular weight distribution curve showed a first peak at a molecular weight of 78,000 and a second peak at a molecular weight of 3.1 million. The tensile strength at break was 41 MPa, the nominal tensile strain at break was 580%, and the Izod impact strength was 115 kJ / m. 2It was.

[0096] Example 2 A suspension of an ethylene-based polymerization catalyst ((A-1) / (A-2)=0.111) was obtained in the same manner as in Example 1, except that the organically modified clay (B-6) obtained in Production Example 6 was used instead of the organically modified clay (B-1).

[0097] A 10-liter autoclave was purged with nitrogen and charged with 6 liters of n-hexane, 5.5 ml of a 20% triisobutylaluminum hexane solution, and 220 mg of the ethylene polymerization catalyst suspension (solids content). While maintaining the temperature inside the autoclave at 60°C, ethylene and hydrogen were continuously supplied to the autoclave so that the ethylene partial pressure was 0.87 MPa and the hydrogen concentration in the gas phase was 200 ppm, resulting in a slurry polymerization of ethylene. After 180 minutes, the pressure was released and the mixture was cooled. The slurry was filtered and dried, yielding 1019 g of particulate ethylene polymer (activity: 4630 g / g catalyst). No adhesion of the ethylene polymer to the reactor walls or stirring blades was observed.

[0098] The resulting ethylene polymer had an intrinsic viscosity of 4.6 dl / g, Mw of 330,000, and Mw / Mn of 4.5. The molecular weight distribution curve showed a first peak at a molecular weight of 81,000 and a second peak at a molecular weight of 3,000,000. The tensile strength at break was 43 MPa, the nominal tensile strain at break was 620%, and the Izod impact strength was 114 kJ / m. 2 It was.

[0099] Example 3 A suspension of an ethylene-based polymerization catalyst ((A-1) / (A-2)=0.111) was obtained in the same manner as in Example 1, except that the organically modified clay (B-7) obtained in Production Example 7 was used instead of the organically modified clay (B-1).

[0100] A 10-liter autoclave was purged with nitrogen and charged with 6 liters of n-hexane, 5.5 ml of a 20% triisobutylaluminum hexane solution, and 250 mg of the ethylene polymerization catalyst suspension (solids content). While maintaining the temperature inside the autoclave at 60°C, ethylene and hydrogen were continuously supplied to the autoclave so that the ethylene partial pressure was 0.87 MPa and the hydrogen concentration in the gas phase was 200 ppm, resulting in a slurry polymerization of ethylene. After 180 minutes, the pressure was released and the system was cooled. The slurry was filtered and dried, yielding 1080 g of particulate ethylene polymer (activity: 4320 g / g catalyst). No adhesion of the ethylene polymer to the reactor walls or stirring blades was observed.

[0101] The resulting ethylene polymer had an intrinsic viscosity of 4.5 dl / g, Mw of 320,000, and Mw / Mn of 4.7. The molecular weight distribution curve showed a first peak at a molecular weight of 80,000 and a second peak at a molecular weight of 2.9 million. The tensile strength at break was 41 MPa, the nominal tensile strain at break was 590%, and the Izod impact strength was 118 kJ / m. 2 It was.

[0102] Example 4 A 300 ml flask equipped with a thermometer and a reflux condenser was purged with nitrogen, and then charged with 20.0 g of the organically modified clay (B-7) obtained in Production Example 7 and 87 ml of n-hexane. 5.0 mg (8 μmol) of diphenylmethylene(cyclopentadienyl)(2-dimethylamino-9-fluorenyl)zirconium dichloride as the metallocene complex (A-1) for producing ultra-high molecular weight polyethylene, 320.4 mg (792 μmol) of bis(n-butylcyclopentadienyl)zirconium dichloride as the metallocene complex (A-2) for producing polyethylene, and 114 ml of a hexane solution of 20% triisobutylaluminum were added and stirred at 60°C for 3 hours. After standing for 1 hour, the supernatant was removed and washed twice with 174 ml of n-hexane, and then 166 ml of n-hexane and 8 ml of a hexane solution of 20% triisobutylaluminum were added to obtain a suspension of an ethylene polymerization catalyst ((A-1) / (A-2)=0.010).

[0103] A 10-liter autoclave was purged with nitrogen and charged with 6 liters of n-hexane, 5.5 ml of a 20% triisobutylaluminum hexane solution, and 250 mg of the ethylene polymerization catalyst suspension (solids content). While maintaining the temperature inside the autoclave at 60°C, ethylene and hydrogen were continuously supplied to the autoclave so that the ethylene partial pressure was 0.87 MPa and the hydrogen concentration in the gas phase was 200 ppm, resulting in a slurry polymerization of ethylene. After 180 minutes, the pressure was released and the system was cooled. The slurry was filtered and dried, yielding 1100 g of particulate ethylene polymer (activity: 4400 g / g catalyst). No adhesion of the ethylene polymer to the reactor walls or stirring blades was observed.

[0104] The resulting ethylene polymer had an intrinsic viscosity of 2.1 dl / g, Mw of 110,000, and Mw / Mn of 3.3. The molecular weight distribution curve showed a first peak at a molecular weight of 82,000 and a shoulder peak at a molecular weight of 3,000,000. The tensile strength at break was 36 MPa, the nominal tensile strain at break was 720%, and the Izod impact strength was 110 kJ / m. 2 It was.

[0105] Example 5 A 300 ml flask equipped with a thermometer and a reflux condenser was purged with nitrogen, and then charged with 20.0 g of the organically modified clay (B-7) obtained in Production Example 7 and 87 ml of n-hexane. 155.7 mg (248 μmol) of diphenylmethylene(cyclopentadienyl)(2-dimethylamino-9-fluorenyl)zirconium dichloride as the metallocene complex (A-1) for producing ultra-high molecular weight polyethylene, 223.3 mg (552 μmol) of bis(n-butylcyclopentadienyl)zirconium dichloride as the metallocene complex (A-2) for producing polyethylene, and 114 ml of a hexane solution of 20% triisobutylaluminum were added and stirred at 60°C for 3 hours. After standing for 1 hour, the supernatant was removed and washed twice with 174 ml of n-hexane, and then 166 ml of n-hexane and 8 ml of a hexane solution of 20% triisobutylaluminum were added to obtain a suspension of an ethylene polymerization catalyst ((A-1) / (A-2)=0.449).

[0106] A 10-liter autoclave was purged with nitrogen and charged with 6 liters of n-hexane, 5.5 ml of a 20% triisobutylaluminum hexane solution, and 250 mg of the ethylene polymerization catalyst suspension (solids content). While maintaining the temperature inside the autoclave at 60°C, ethylene and hydrogen were continuously supplied to the autoclave so that the ethylene partial pressure was 0.87 MPa and the hydrogen concentration in the gas phase was 200 ppm, resulting in a slurry polymerization of ethylene. After 180 minutes, the pressure was released and the system was cooled. The slurry was filtered and dried, yielding 1053 g of particulate ethylene polymer (activity: 4210 g / g catalyst). No adhesion of the ethylene polymer to the reactor walls or stirring blades was observed.

[0107] The resulting ethylene polymer had an intrinsic viscosity of 9.1 dl / g, Mw=900,000, and Mw / Mn=7.5. The molecular weight distribution curve showed a first peak at a molecular weight of 79,000 and a second peak at a molecular weight of 3.1 million. The tensile strength at break was 47 MPa, the nominal tensile strain at break was 560%, and the Izod impact strength was 116 kJ / m. 2 It was.

[0108] Example 6 A 300 ml flask equipped with a thermometer and a reflux condenser was purged with nitrogen, and then charged with 20.0 g of the organically modified clay (B-1) obtained in Production Example 1 and 87 ml of n-hexane. 57.2 mg (80 μmol) of diphenylmethylene(cyclopentadienyl)(2-dimethylamino-9-fluorenyl)hafnium dichloride (molecular weight: 715.0) synthesized by a known method as the metallocene complex (A-1) for producing ultra-high molecular weight polyethylene, 282.6 mg (720 μmol) of bisindenylzirconium dichloride (molecular weight: 392.4) synthesized by a known method as the metallocene complex (A-2) for producing polyethylene, and 114 ml of a hexane solution of 20% triisobutylaluminum were added and stirred at 60° C. for 3 hours. After standing for 1 hour, the supernatant was removed and washed twice with 174 ml of n-hexane, and then 166 ml of n-hexane and 8 ml of a hexane solution of 20% triisobutylaluminum were added to obtain a suspension of an ethylene polymerization catalyst ((A-1) / (A-2)=0.111).

[0109] A 10-liter autoclave was purged with nitrogen and charged with 6 liters of n-hexane, 5.5 ml of a 20% triisobutylaluminum hexane solution, and 150 mg of the ethylene polymerization catalyst suspension (solids content). While maintaining the temperature inside the autoclave at 60°C, ethylene and hydrogen were continuously supplied to the autoclave so that the ethylene partial pressure was 0.87 MPa and the hydrogen concentration in the gas phase was 200 ppm, resulting in a slurry polymerization of ethylene. After 180 minutes, the pressure was released and the mixture was cooled. The slurry was filtered and dried, yielding 1173 g of particulate ethylene polymer (activity 7820 g / g catalyst). No adhesion of the ethylene polymer to the reactor walls or stirring blades was observed.

[0110] The resulting ethylene polymer had an intrinsic viscosity of 6.0 dl / g, Mw=490,000, and Mw / Mn=4.5. The molecular weight distribution curve showed a first peak at a molecular weight of 220,000 and a second peak at a molecular weight of 5,000,000. The tensile strength at break was 52 MPa, the nominal tensile strain at break was 550%, and the Izod impact strength was 120 kJ / m. 2 It was.

[0111] Example 7 A suspension of an ethylene-based polymerization catalyst ((A-1) / (A-2)=0.111) was obtained in the same manner as in Example 6, except that the organically modified clay (B-2) obtained in Production Example 2 was used instead of the organically modified clay (B-1).

[0112] A 10-liter autoclave was purged with nitrogen and charged with 6 liters of n-hexane, 5.5 ml of a 20% triisobutylaluminum hexane solution, and 150 mg of the ethylene polymerization catalyst suspension (solids content). While maintaining the temperature inside the autoclave at 60°C, ethylene and hydrogen were continuously supplied to the autoclave so that the ethylene partial pressure was 0.87 MPa and the hydrogen concentration in the gas phase was 200 ppm, resulting in a slurry polymerization of ethylene. After 180 minutes, the pressure was released and the mixture was cooled. The slurry was filtered and dried, yielding 1169 g of particulate ethylene polymer (activity 7790 g / g catalyst). No adhesion of the ethylene polymer to the reactor walls or stirring blades was observed.

[0113] The resulting ethylene polymer had an intrinsic viscosity of 5.8 dl / g, Mw of 480,000, and Mw / Mn of 4.8. The molecular weight distribution curve showed a first peak at a molecular weight of 220,000 and a second peak at a molecular weight of 4.8 million. The tensile strength at break was 51 MPa, the nominal tensile strain at break was 550%, and the Izod impact strength was 117 kJ / m. 2 It was.

[0114] Example 8 A 300 ml flask equipped with a thermometer and a reflux condenser was purged with nitrogen, and then charged with 20.0 g of the organically modified clay (B-1) obtained in Production Example 1 and 87 ml of n-hexane. 125.8 mg (160 μmol) of diphenylmethylene(cyclopentadienyl)(2,7-bis(dimethylamino)-9-fluorenyl)hafnium dichloride (molecular weight: 786.2) synthesized by a known method as the metallocene complex (A-1) for producing ultra-high molecular weight polyethylene, 285.8 mg (640 μmol) of dimethylsilylene(cyclopentadienyl)(fluorenyl)zirconium dichloride (molecular weight: 446.6) synthesized by a known method as the metallocene complex (A-2) for producing polyethylene, and 114 ml of a hexane solution of 20% triisobutylaluminum were added and stirred at 60° C. for 3 hours. After standing for 1 hour, the supernatant was removed and washed twice with 174 ml of n-hexane, and then 166 ml of n-hexane and 8 ml of a hexane solution of 20% triisobutylaluminum were added to obtain a suspension of an ethylene polymerization catalyst ((A-1) / (A-2)=0.250).

[0115] A 10-liter autoclave was purged with nitrogen and charged with 6 liters of n-hexane, 5.5 ml of a 20% triisobutylaluminum hexane solution, and 250 mg of the ethylene polymerization catalyst suspension (solids content). While maintaining the temperature inside the autoclave at 60°C, ethylene and hydrogen were continuously supplied to the autoclave so that the ethylene partial pressure was 0.87 MPa and the hydrogen concentration in the gas phase was 200 ppm, resulting in a slurry polymerization of ethylene. After 180 minutes, the pressure was released and the system was cooled. The slurry was filtered and dried, yielding 1028 g of particulate ethylene polymer (activity: 4110 g / g catalyst). No adhesion of the ethylene polymer to the reactor walls or stirring blades was observed.

[0116] The resulting ethylene polymer had an intrinsic viscosity of 13.8 dl / g, Mw of 1,600,000, and Mw / Mn of 4.8. The molecular weight distribution curve showed a first peak at a molecular weight of 470,000 and a second peak at a molecular weight of 10,000,000. The tensile strength at break was 55 MPa, the nominal tensile strain at break was 420%, and the Izod impact strength was 124 kJ / m. 2 It was.

[0117] Comparative Example 1 A 300 ml flask equipped with a thermometer and a reflux condenser was purged with nitrogen, and then charged with 20.0 g of the organically modified clay (B-1) obtained in Production Example 1 and 87 ml of n-hexane. 2.5 mg (4 μmol) of diphenylmethylene(cyclopentadienyl)(2-dimethylamino-9-fluorenyl)zirconium dichloride as the metallocene complex (A-1) for producing ultra-high molecular weight polyethylene, 322.0 mg (796 μmol) of bis(n-butylcyclopentadienyl)zirconium dichloride as the metallocene complex (A-2) for producing polyethylene, and 114 ml of a hexane solution of 20% triisobutylaluminum were added and stirred at 60°C for 3 hours. After standing for 1 hour, the supernatant was removed and washed twice with 174 ml of n-hexane, and then 166 ml of n-hexane and 8 ml of a hexane solution of 20% triisobutylaluminum were added to obtain a suspension of an ethylene polymerization catalyst ((A-1) / (A-2)=0.005).

[0118] A 10-liter autoclave was purged with nitrogen and charged with 6 liters of n-hexane, 5.5 ml of a 20% triisobutylaluminum hexane solution, and 200 mg of the ethylene polymerization catalyst suspension (solids content equivalent). While maintaining the temperature inside the autoclave at 60°C, ethylene and hydrogen were continuously supplied to the autoclave so that the ethylene partial pressure was 0.87 MPa and the hydrogen concentration in the gas phase was 200 ppm, resulting in a slurry polymerization of ethylene. After 180 minutes, the pressure was released and the mixture was cooled. The slurry was filtered and dried, yielding 1038 g of particulate ethylene polymer (activity 5190 g / g catalyst). No adhesion of the ethylene polymer to the reactor walls or stirring blades was observed.

[0119] The obtained ethylene polymer had an intrinsic viscosity of 1.8 dl / g, Mw of 92,000, and Mw / Mn of 3.1. The molecular weight distribution curve showed a first peak at a molecular weight of 80,000 and a slight shoulder peak at a molecular weight of 2.9 million. The tensile strength at break was 26 MPa, the nominal tensile strain at break was 310%, and the Izod impact strength was 95 kJ / m. 2 It was.

[0120] Comparative Example 2 A 300 ml flask equipped with a thermometer and a reflux condenser was purged with nitrogen, and then charged with 20.0 g of the organically modified clay (B-1) obtained in Production Example 1 and 87 ml of n-hexane. 200.9 mg (320 μmol) of diphenylmethylene(cyclopentadienyl)(2-dimethylamino-9-fluorenyl)zirconium dichloride as the metallocene complex (A-1) for producing ultra-high molecular weight polyethylene, 194.2 mg (480 μmol) of bis(n-butylcyclopentadienyl)zirconium dichloride as the metallocene complex (A-2) for producing polyethylene, and 114 ml of a hexane solution of 20% triisobutylaluminum were added and stirred at 60° C. for 3 hours. After standing for 1 hour, the supernatant was removed and washed twice with 174 ml of n-hexane, and then 166 ml of n-hexane and 8 ml of a hexane solution of 20% triisobutylaluminum were added to obtain a suspension of an ethylene polymerization catalyst ((A-1) / (A-2)=0.667).

[0121] A 10-liter autoclave was purged with nitrogen and charged with 6 liters of n-hexane, 5.5 ml of a 20% triisobutylaluminum hexane solution, and 300 mg of the ethylene polymerization catalyst suspension (solids content). While maintaining the temperature inside the autoclave at 60°C, ethylene and hydrogen were continuously supplied to the autoclave so that the ethylene partial pressure was 0.87 MPa and the hydrogen concentration in the gas phase was 200 ppm, resulting in a slurry polymerization of ethylene. After 180 minutes, the pressure was released and the system was cooled. The slurry was filtered and dried, yielding 1140 g of particulate ethylene polymer (activity 3800 g / g catalyst). Adhesion of the ethylene polymer to the reactor walls and stirring blades was observed, with some of the polymer forming agglomerates.

[0122] The obtained ethylene polymer had an intrinsic viscosity of 9.8 dl / g, Mw of 1,000,000, and Mw / Mn of 13. The molecular weight distribution curve showed a first peak at a molecular weight of 2.8 million and a second peak at a molecular weight of 79,000. The tensile strength at break was 45 MPa, the nominal tensile strain at break was 220%, and the Izod impact strength was 97 kJ / m. 2 It was.

[0123] Comparative Example 3 A suspension of an ethylene-based polymerization catalyst ((A-1) / (A-2)=0.111) was obtained in the same manner as in Example 1, except that the organically modified clay (B-3) obtained in Production Example 3 was used instead of the organically modified clay (B-1).

[0124] A 10-liter autoclave was purged with nitrogen and charged with 6 liters of n-hexane, 5.5 ml of a 20% triisobutylaluminum hexane solution, and 320 mg of the ethylene polymerization catalyst suspension (solids content). While maintaining the temperature inside the autoclave at 60°C, ethylene and hydrogen were continuously supplied to the autoclave so that the ethylene partial pressure was 0.87 MPa and the hydrogen concentration in the gas phase was 200 ppm, resulting in a slurry polymerization of ethylene. After 180 minutes, the pressure was released and the system was cooled. The slurry was filtered and dried, yielding 1014 g of particulate ethylene polymer (activity: 3170 g / g catalyst). No adhesion of the ethylene polymer to the reactor walls or stirring blades was observed.

[0125] The resulting ethylene polymer had an intrinsic viscosity of 4.6 dl / g, Mw of 330,000, and Mw / Mn of 4.5. The molecular weight distribution curve showed a first peak at a molecular weight of 79,000 and a second peak at a molecular weight of 3,000,000. The tensile strength at break was 40 MPa, the nominal tensile strain at break was 380%, and the Izod impact strength was 113 kJ / m. 2 It was.

[0126] Comparative Example 4 A suspension of an ethylene-based polymerization catalyst ((A-1) / (A-2)=0.111) was obtained in the same manner as in Example 1, except that the organically modified clay (B-4) obtained in Production Example 4 was used instead of the organically modified clay (B-1).

[0127] A 10-liter autoclave was purged with nitrogen and charged with 6 liters of n-hexane, 5.5 ml of a 20% triisobutylaluminum hexane solution, and 200 mg of the ethylene polymerization catalyst suspension (solids content equivalent). While maintaining the temperature inside the autoclave at 60°C, ethylene and hydrogen were continuously supplied to the autoclave so that the ethylene partial pressure was 0.87 MPa and the hydrogen concentration in the gas phase was 200 ppm, resulting in a slurry polymerization of ethylene. After 180 minutes, the pressure was released and the system was cooled. The slurry was filtered and dried, yielding 1020 g of particulate ethylene polymer (activity 5100 g / g catalyst). Note that a large amount of powder adhered to the reactor walls and stirring blades, with some of the powder agglomerating.

[0128] The resulting ethylene polymer had an intrinsic viscosity of 4.4 dl / g, Mw of 320,000, and Mw / Mn of 4.6. The molecular weight distribution curve showed a first peak at a molecular weight of 78,000 and a second peak at a molecular weight of 3,000,000. The tensile strength at break was 41 MPa, the nominal tensile strain at break was 380%, and the Izod impact strength was 117 kJ / m. 2 It was.

[0129] Comparative Example 5 A suspension of an ethylene-based polymerization catalyst ((A-1) / (A-2)=0.111) was obtained in the same manner as in Example 1, except that the organically modified clay (B-5) obtained in Production Example 5 was used instead of the organically modified clay (B-1).

[0130] A 10-liter autoclave was purged with nitrogen and charged with 6 liters of n-hexane, 5.5 ml of a 20% triisobutylaluminum hexane solution, and 200 mg of the ethylene polymerization catalyst suspension (solids content equivalent). While maintaining the temperature inside the autoclave at 60°C, ethylene and hydrogen were continuously supplied to the autoclave so that the ethylene partial pressure was 0.87 MPa and the hydrogen concentration in the gas phase was 200 ppm, resulting in a slurry polymerization of ethylene. After 180 minutes, the pressure was released and the system was cooled. The slurry was filtered and dried, yielding 1022 g of particulate ethylene polymer (activity 5110 g / g catalyst). Powder adhesion was observed on the reactor walls and stirring blades.

[0131] The resulting ethylene polymer had an intrinsic viscosity of 4.5 dl / g, Mw of 320,000, and Mw / Mn of 4.2. The molecular weight distribution curve showed a first peak at a molecular weight of 81,000 and a second peak at a molecular weight of 2.9 million. The tensile strength at break was 41 MPa, the nominal tensile strain at break was 360%, and the Izod impact strength was 114 kJ / m. 2 It was.

[0132] [Table 2]

[0133] [Table 3] [Industrial Applicability]

[0134] The ethylene polymerization catalyst of the present invention is expected to be a catalyst capable of producing, by a simple process, an ethylene polymer that can be molded into a molded article having an excellent balance between processability and mechanical properties of the molded article.

Claims

1. The catalyst for ethylene polymerization comprises, as constituent components, at least a metallocene complex (A), an organically modified clay (B), and an alkylaluminum (C), wherein the metallocene complex (A) is a metallocene complex containing a metallocene complex (A-1) for producing ultra-high molecular weight polyethylene and a metallocene complex (A-2) for producing polyethylene, in a ratio of metallocene complex (A-1) / metallocene complex (A-2) (amount of substance) of 0.01 to 0.45, and the organically modified clay (B) is an organically modified clay that satisfies the following in particle size distribution measured by laser diffraction / scattering particle size distribution measurement: a) a median diameter and a mode diameter of 10 to 20 μm, the difference between which is 5 μm or less, and b) the proportions of particles of 5 μm or less and 33 μm or more are 5 vol % or less, respectively.

2. 2. The ethylene polymerization catalyst according to claim 1, wherein the metallocene complex (A-1) for producing ultra-high molecular weight polyethylene is a metallocene complex represented by the following general formula (1): 【Chemistry 1】 [In the formula, M １ is a zirconium atom or a hafnium atom, and X １ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms; R １ is a cyclopentadienyl group represented by the following general formula (2), 【Chemistry 2】 (In the formula, R ４ ~R ７ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms. R ２ is a fluorenyl group represented by the following general formula (3), 【Transformation 3】 (In the formula, R ８ ~R １５ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 30 carbon atoms, an arylalkylamino group having 7 to 30 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms, at least one of which is an alkylamino group having 1 to 20 carbon atoms or a hydrocarbon group having 4 to 20 carbon atoms and a quaternary carbon atom. R ３ is R represented by the following general formula (4) or the following general formula (5): １ and R ２ is a crosslinking unit of 【Chemistry 4】 【Transformation 5】 (In the formula, R １６ ~R １７ and R １８ ~R １９ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 30 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms; M ２ is a silicon atom, a germanium atom, or a tin atom. l is a natural number from 1 to 5.

3. 2. The ethylene polymerization catalyst according to claim 1, wherein the polyethylene-producing metallocene complex (A-2) is a metallocene complex represented by the following general formula (6) or (7): 【Transformation 6】 【Transformation 7】 [In the formula, M ３ and M ４ are each independently a titanium atom, a zirconium atom, or a hafnium atom, and X ２ and X ３ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms; R ２０ and R ２３ are each independently a cyclopentadienyl group represented by the following general formula (8) or an indenyl group represented by the following general formula (9), 【Transformation 8】 【Chemistry 9】 (In the formula, R ２５ ~R ２８ and R ２９ ~R ３４ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms. R ２１ and R ２４ are each independently a cyclopentadienyl group, an indenyl group, or a fluorenyl group represented by the following general formulas (10) to (12), 【Chemistry 10】 【Chemistry 11】 (In the formula, R ３５ ~R ３８ and R ３９ ~R ４４ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms. 【Chemistry 12】 (In the formula, R ４５ ~R ５２ are each independently a hydrogen atom, a halogen atom, an alkoxy group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms (excluding hydrocarbon groups having 4 to 20 carbon atoms and a quaternary carbon atom), or a trialkylsilylalkylene group having 4 to 20 carbon atoms. R ２２ is R represented by the following general formula (13) or the following general formula (14): ２０ and R ２１ is a crosslinking unit of 【Chemistry 13】 【Chemistry 14】 (In the formula, R ５３ ~R ５４ and R ５５ ~R ５６ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 30 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkylene group having 2 to 20 carbon atoms, a dialkylaminoalkylene group having 3 to 20 carbon atoms, or a trialkylsilylalkylene group having 4 to 20 carbon atoms; M ５ is a silicon atom, a germanium atom, or a tin atom. m is a natural number from 1 to 5.

4. 2. The ethylene polymerization catalyst according to claim 1, wherein the organically modified clay (B) is a tertiary ammonium ion-modified clay or clay mineral represented by the following general formula (15): 【Chemistry 15】 (In the formula, R ５７ is an alkyl group having 12 to 30 carbon atoms or an alkenyl group having 12 to 30 carbon atoms, and R ５８ ~R ５９ are each independently an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms.

5. 2. The ethylene polymerization catalyst according to claim 1, wherein the organically modified clay (B) is an organically modified montmorillonite or an organically modified hectorite.

Images