JP7752515B2 - Catalyst for olefin polymerization and method for producing olefin polymer - Google Patents

Description

The present invention relates to an olefin polymerization catalyst and a method for producing an olefin polymer using the olefin polymerization catalyst.

By blending carbon materials such as graphite, graphene, and carbon nanotubes (CNTs) into polyolefins, it is possible to impart high thermal conductivity, electrical conductivity, and weather resistance to the polyolefins (see, for example, Patent Document 1). However, there is a problem in that it is difficult to disperse these carbon materials in polyolefins.

In order to improve the dispersibility of carbon materials in polyolefins, methods have been proposed for producing composites of carbon materials and polyolefins by polymerizing using a polymerization catalyst in which a metal complex is supported or impregnated on the carbon material (see, for example, Patent Documents 2 to 4). However, there is room for further improvement in terms of olefin polymerization activity and dispersibility of the carbon material. Furthermore, all of these methods use expensive organoaluminum oxy compounds such as methylaluminoxane (MAO) as co-catalysts, and there is also a need to reduce production costs.

JP 2017-071079 A Japanese Patent Application Laid-Open No. 2006-176601 JP 2007-161741 A Special Publication No. 2005-506404

The objective of the present invention is to provide an olefin polymerization catalyst that exhibits high polymerization activity and is capable of producing olefin polymers in which carbon materials are efficiently dispersed, and a method for producing olefin polymers using the olefin polymerization catalyst.

Another objective of the present invention is to provide an olefin polymerization catalyst that exhibits high polymerization activity even when using an expensive organoaluminum oxy-compound in a smaller amount than conventionally used, and that can produce an olefin polymer in which a carbon material is efficiently dispersed, and a method for producing an olefin polymer using the olefin polymerization catalyst.

The inventors conducted extensive research to solve the above problems. As a result, they discovered that the above problems could be solved by using a specific carbon material, leading to the completion of the present invention.

The olefin polymerization catalyst according to the present invention comprises:
A carbon material (A) that satisfies the following requirements (AI) and (A-II);
At least one component (B) selected from the group consisting of the following (BI) and (B-II):
and a transition metal compound (C) represented by the following general formula (CI):
(A-I) The oxygen atom/carbon atom molar ratio measured by X-ray photoelectron spectroscopy (XPS) is 0.018 or more and 0.400 or less;
(A-II) The specific surface area measured by the BET multipoint method is 100 m ² /g or more and 5000 ^{m 2} /g or less;
(B-I) Organoaluminum oxy compounds;
(B-II) a compound that reacts with the transition metal compound (C) to form an ion pair;
L _m MX _n ... (C-I)
[In general formula (C-I), M is an atom selected from the group consisting of atoms of Groups 3, 4, 5, 6, 7, 8, 9, 10, and 11 of the periodic table, and lanthanide atoms;
L is selected from the group consisting of η-bonding cyclic anionic ligands, σ-bonding anionic ligands, and π-bonding neutral ligands, and multiple Ls may be the same or different, and multiple Ls may be connected via a substituent in L;
m is an integer of 0 or greater,
n is an integer of 1 to 6 that satisfies the valence of M;
X is selected from a hydrogen atom, a halogen atom, a hydrocarbon group, a halogen-containing group, a silicon-containing group, an oxygen-containing group, a sulfur-containing group, a nitrogen-containing group, a phosphorus-containing group, and a diene derivative group, and when n is 2 or more, multiple Xs may be the same or different and may be bonded to each other to form a ring.

The present invention provides an olefin polymerization catalyst that exhibits high polymerization activity and is capable of producing olefin polymers in which carbon materials are efficiently dispersed, as well as a method for producing olefin polymers using the olefin polymerization catalyst.

The present invention also provides an olefin polymerization catalyst that exhibits high polymerization activity even when using an expensive organoaluminum oxy-compound in a smaller amount than conventionally used, and that can produce an olefin polymer in which a carbon material is efficiently dispersed, as well as a method for producing an olefin polymer using the olefin polymerization catalyst.

The present invention will be described in detail below.
[Olefin polymerization catalyst]
The olefin polymerization catalyst of the present invention comprises
A carbon material (A) that satisfies the following requirements (AI) and (A-II);
At least one component (B) selected from the group consisting of the following (BI) and (B-II):
and a transition metal compound (C) represented by the following general formula (CI):

(AI) The molar ratio of oxygen atoms to carbon atoms measured by X-ray photoelectron spectroscopy (XPS) is 0.018 or more and 0.400 or less.
(A-II) The specific surface area measured by the BET multipoint method is 100 m ² /g or more and 5000 ^{m 2} /g or less.

(B-I) Organoaluminum oxy compounds;
(B-II) a compound that reacts with the transition metal compound (C) to form an ion pair;

L _m MX _n ... (C-I)
In the general formula (C-I), M is an atom selected from the group consisting of atoms of Groups 3, 4, 5, 6, 7, 8, 9, 10, and 11 in the periodic table, and lanthanide atoms; L is selected from the group consisting of η-bonding cyclic anionic ligands, σ-bonding anionic ligands, and π-bonding neutral ligands; multiple Ls may be the same or different from one another, or multiple Ls may be connected via a substituent within L; m is an integer of 0 or greater; n is an integer of 1 to 6 that satisfies the valence of M; X is selected from a hydrogen atom, a halogen atom, a hydrocarbon group, a halogen-containing group, a silicon-containing group, an oxygen-containing group, a sulfur-containing group, a nitrogen-containing group, a phosphorus-containing group, and a diene derivative group; when n is 2 or greater, multiple Xs may be the same or different from one another, or may be bonded to each other to form a ring.

Each component constituting the olefin polymerization catalyst of the present invention will be described below.
<Carbon material (A)>
The carbon material (A) used in the present invention satisfies the following requirements (AI) and (A-II).

(A-I) The oxygen atom/carbon atom molar ratio measured by X-ray photoelectron spectroscopy (XPS) is 0.018 or more and 0.400 or less, preferably 0.020 or more and 0.250 or less, and more preferably 0.022 or more and 0.200 or less.

The oxygen atom/carbon atom molar ratio is a value obtained by X-ray photoelectron spectroscopy (XPS) measurement, and specifically, the oxygen atom/carbon atom molar ratio is calculated from the peak areas of oxygen atoms and carbon atoms in the spectrum obtained from the carbon material (A).

A higher oxygen atom/carbon atom molar ratio is preferable because it increases the amount of oxygen atoms that can come into contact with component (B), which will be described later. However, if the oxygen atom/carbon atom molar ratio is too high, the two-dimensional sheet structure of sp2 ^- bonded carbon in the carbon material (A) tends to decrease.

The oxygen atoms in the carbon material (A) may be formed by substituting some of the carbon atoms in the carbon material with oxygen atoms, may be contained within a substituent on the carbon material, or may be contained in a compound coordinated to or adsorbed on the surface or pores of the carbon material. However, it is preferable that the oxygen atoms are present as oxygen-atom-containing functional groups within a substituent on the carbon material. Specific examples of oxygen-atom-containing functional groups include hydroxyl groups, ether groups, epoxy groups, carbonyl groups, and carboxyl groups.

The amount of oxygen atoms in the carbon material (A) can be controlled by the production conditions of the carbon material, heat treatment (e.g., drying, calcination), water absorption treatment, surface modification or modification treatment (e.g., functional group introduction, oxidation treatment, reduction treatment), etc.

(A-II) The specific surface area measured by the BET multipoint method is 100 ^{m 2} /g or more and 5000 ^{m 2} /g or less, preferably 150 ^{m 2} /g or more and 3000 ^{m 2} /g or less, more preferably 200 m ² /g or more and 2000 ^{m 2} /g or less.

The specific surface area is a value obtained by the BET (Brunauer-Emmett-Teller) multipoint method using an adsorption isotherm. Specifically, the adsorption isotherm of carbon material (A) is measured using nitrogen gas as the adsorbate after vacuum heating and degassing at a temperature of 50°C to 300°C. A BET plot is then created from the adsorption isotherm, and the monomolecular adsorption amount is determined from the slope and intercept of the plot, from which the specific surface area is calculated.

When using a porous carbon material (A), if the specific surface area is too high, the pore diameter will become smaller (in other words, the proportion of micropores will increase), hindering contact with component (B) and the transition metal compound (C), which will be described later.

In the case of the carbon material (A) having pores, the pore volume is preferably 0.1 cm ³ /g or more and 5.0 cm ³ /g or less, more preferably 0.3 cm ³ /g or more and 4.0 cm ³ /g or less.

The specific surface area of the carbon material (A) can be controlled by the raw material, size (nano-sizing), shape, and pores of the carbon material. Methods for forming pores include the introduction of a template source, as exemplified in JP 2020-093977 A, and activation treatment methods.

The carbon material (A) used in the present invention is a solid carbon material and is not particularly limited as long as it satisfies the above requirements (A-1) and (A-II), and includes crystalline, low-crystalline, amorphous, and mixtures thereof.

Among the carbon materials, examples of crystalline carbon include carbon nanotubes (e.g., single-walled carbon nanotubes (SWCNT), double-walled carbon nanotubes (DWCNT), and multi-walled carbon nanotubes (MWCNT)), graphene (e.g., single-layer graphene, multi-layer graphene), fullerenes (e.g., buckminsterfullerene, higher fullerenes), graphite (e.g., natural graphite, artificial graphite), and diamond. Examples of low-crystalline and amorphous carbon include carbon black and activated carbon.

The carbon material (A) may be a carbon material that has been subjected to surface modification or modification treatment (for example, functional group introduction, oxidation treatment, or reduction treatment), may contain metals or the like, or may have some of the carbon atoms substituted with other atoms.

The carbon material (A) used in the present invention can be one produced by a conventionally known method, or a commercially available product can also be used.

For example, carbon nanotubes can be produced by methods such as arc discharge, laser deposition, and gas-phase chemical vapor deposition, as exemplified in JP 2009-196873 A, and surface modification treatments can be performed using methods such as those exemplified in JP 2014-501689 A. Commercially available products include Nanocyl's "Multi Walled Carbon Nanotubes NANOCYL NC7000" and "Multi Walled Carbon Nanotubes NANOCYL NC3101," SkySpring Nanomaterials' "Single Walled Nanotubes OH Functionalized" and "Multi Walled Nanotubes OH Functionalized," and IoLiTec's "Multi-Walled Carbon Nanotubes, -OH Functionalized."

Graphene can be produced by methods such as arc discharge, laser deposition, gas-phase chemical vapor deposition, heat treatment of silicon carbide, mechanical exfoliation, and ultrasonic exfoliation after chemical oxidation, as exemplified in JP 2014-152095 A. Commercially available products include XG Sciences' "Graphene Nanoplatelets xGnP," and Graphitene's "Reduced Graphene Oxide," "Boron-doped Graphene Powder," "Phosphorus-doped Graphene Powder," "Sulfur-doped Graphene Powder," "Nitrogen-doped Graphene Powder," and "Graphene Film."

Fullerenes can be produced by methods such as arc discharge, resistance heating, laser evaporation, combustion, and pyrolysis, as exemplified in JP 2013-241379 A, and hydroxyl groups or carboxyl groups can be introduced onto the carbon of the fullerene by chemical treatment, etc. Commercially available products include "C ₆₀ PCPA" and "C ₆₀ (OH) _22-26 " from IoLiTec.

Graphite can be broadly divided into natural graphite and artificial graphite. Examples of natural graphite include flake graphite, lump graphite (flake graphite), and amorphous graphite. Artificial graphite can be produced by methods such as precipitation from Fe, Ni/C melts, decomposition of carbides of Si, Al, etc., cooling of carbon melts under high temperature and pressure, and high-temperature decomposition and deposition of hydrocarbon gases, as exemplified in JP 02-083208 A. Commercially available products include Nippon Graphite's "High Purity Graphite Powder SP-270" and "Artificial Graphite Powder HAG-150."

Carbon black can be produced by pyrolysis or incomplete combustion of hydrocarbons such as oil and natural gas. Specific methods include the furnace process, channel process, acetylene process, and pine soot process.

Activated carbon can be produced by carbonizing and activating wood (e.g., charcoal, sawdust, bark), fruit shells (e.g., coconut shells), grain husks (e.g., rice husks), coal (e.g., peat, tar, coke), and petroleum (e.g., tar, pitch) at high temperatures. Commercially available products include "Porous Carbon CNovel" from Toyo Tanso Co., Ltd. and "Triporous" from Sony Corporation.

The carbon material (A) preferably has a two-dimensional sheet structure of sp2 ^- bonded carbon, and preferably has a cylindrically wound or spherical structure of the two-dimensional sheet. Specifically, the carbon material (A) preferably contains at least one selected from the group consisting of carbon nanotubes, graphene, fullerene, graphite, and activated carbon.

There are no particular restrictions on the shape or size of the carbon material (A), and it may be in the form of granules, powder, fibers, sheets, etc. However, if it is in the form of granules or powder, it is preferable that it has mesopores or macropores, as this promotes contact with the component (B) and transition metal compound (C), which will be described later.

The carbon material (A) may be dried or calcined at a temperature of 0°C or higher and 1000°C or lower, preferably 50°C or higher and 800°C or lower, if necessary, before use.

<Component (B)>
Component (B) used in the present invention is at least one component selected from the group consisting of organoaluminum oxy compounds (BI) and compounds (B-II) (hereinafter also referred to as "ionic compounds (B-II)") that react with transition metal compounds (C) to form ion pairs. Component (B) preferably has a functional group that can form a chemical bond or electronic interaction with the oxygen atom-containing functional group in the carbon material (A).

<Organoaluminum oxy compound (B-I)>
Examples of the organoaluminum oxy compound (B-I) include conventionally known aluminoxanes such as compounds represented by the following general formula [b1] and compounds represented by the following general formula [b2], modified methylaluminoxanes having a structure represented by the following general formula [b3], and boron-containing organoaluminum oxy compounds represented by the following general formula [b4]:

In formulas [b1] and [b2], R is a hydrocarbon group having 1 to 20 carbon atoms, preferably a methyl group, and n is an integer of 2 or greater, preferably 3 or greater, and more preferably 5 or greater. In formulas [b1] and [b2], methylaluminoxane, in which R is a methyl group, is preferably used.

In formula [b3], Me is a methyl group, R is a hydrocarbon group having from 2 to 20 carbon atoms, and m and n are each independently an integer of 2 or greater. Multiple Rs may be the same or different. Modified methylaluminoxane [b3] can be prepared using trimethylaluminum and an alkylaluminum other than trimethylaluminum. Such modified methylaluminoxane [b3] is generally called MMAO (modified methyl aluminoxane). MMAO can be prepared specifically by the methods described in U.S. Pat. No. 4,960,878 and U.S. Pat. No. 5,041,584.

Modified methylaluminoxanes prepared using trimethylaluminum and triisobutylaluminum (i.e., R is an isobutyl group in general formula [b3]) are also commercially produced by Tosoh Finechem Corporation and other companies under the trade names MMAO and TMAO.

MMAO is an aluminoxane with improved solubility in various solvents and improved storage stability. Specifically, unlike compounds that are insoluble or poorly soluble in benzene, such as compounds represented by general formula [b1] or [b2], MMAO is soluble in aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons.

In formula [b4], R is a hydrocarbon group having 1 to 20 carbon atoms. Multiple Rs may be the same or different.

Examples of the hydrocarbon group in the formulae [b1], [b2], [b3] and [b4] include a methyl group, an ethyl group, a 1-propyl group, a 1-butyl group, a 1-pentyl group, a 1-hexyl group, a 1-heptyl group, a 1-octyl group, an isopropyl group, a sec-butyl group (butan-2-yl group), a tert-butyl group (2-methylpropan-2-yl group), an isobutyl group (2-methylpropyl group), a pentan-2-yl group, a 2-methylpropyl ... linear or branched alkyl groups such as methylbutyl, isopentyl (3-methylbutyl), neopentyl (2,2-dimethylpropyl), cyamyl (1,2-dimethylpropyl), isohexyl (4-methylpentyl), 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, thexyl (2,3-dimethylbut-2-yl), and 4,4-dimethylpentyl;
linear or branched alkenyl groups or unsaturated double bond-containing groups such as a vinyl group, an allyl group, a propenyl group (prop-1-en-1-yl group), an iso-propenyl group (prop-1-en-2-yl group), an allenyl group (prop-1,2-dien-1-yl group), a but-3-en-1-yl group, a crotyl group (but-2-en-1-yl group), a but-3-en-2-yl group, a methallyl group (2-methylallyl group), a buta-1,3-dienyl group, a pent-4-en-1-yl group, a pent-3-en-1-yl group, a pent-2-en-1-yl group, an iso-pentenyl group (3-methylbut-3-en-1-yl group), a 2-methylbut-3-en-1-yl group, a pent-4-en-2-yl group, or a prenyl group (3-methylbut-2-en-1-yl group);
linear or branched alkynyl groups or unsaturated triple bond-containing groups such as ethynyl, prop-2-yn-1-yl, and propargyl (prop-1-yn-1-yl); aromatic-containing linear or branched alkyl groups and unsaturated double bond-containing groups such as benzyl, 2-methylbenzyl, 4-methylbenzyl, 2,4,6-trimethylbenzyl, 3,5-dimethylbenzyl, cuminyl (4-isopropylbenzyl), 2,4,6-tri-isopropylbenzyl, 4-tert-butylbenzyl, 3,5-di-tert-butylbenzyl, 1-phenylethyl, benzhydryl (diphenylmethyl), and cumyl;
cyclic saturated hydrocarbon groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cycloheptatrienyl group, a norbornyl group, a norbornenyl group, a 1-adamantyl group, and a 2-adamantyl group;
Examples of aromatic substituents (aryl groups) include a phenyl group, a tolyl group (methylphenyl group), a xylyl group (dimethylphenyl group), a mesityl group (2,4,6-trimethylphenyl group), a cumenyl group (isopropylphenyl group), a duryl group (2,3,5,6-tetramethylphenyl group), a 2,6-di-isopropylphenyl group, a 2,4,6-tri-isopropylphenyl group, a 4-tert-butylphenyl group, a 3,5-di-tert-butylphenyl group, a naphthyl group, a biphenyl group, a terphenyl group, a binaphthyl group, an acenaphthalenyl group, a phenanthryl group, an anthracenyl group, a pyrenyl group, and a ferrocenyl group.

Compounds in which some of the multiple Rs in the formulas [b1], [b2], [b3], and [b4] are replaced with hydrogen atoms, halogen atoms, halogen-containing groups, or oxygen-containing groups can also be used as the organoaluminum oxy compound (B-I).

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of the halogen-containing group include those in which some of the hydrogen atoms in the hydrocarbon group have been substituted with the halogen atoms.

Examples of the oxygen-containing group include alkoxy groups such as hydroxyl, methoxy, ethoxy, n-propoxy, iso-propoxy, allyloxy, n-butoxy, sec-butoxy, iso-butoxy, tert-butoxy, benzyloxy, and methoxymethoxy; aryloxy groups such as phenoxy, 2,6-dimethylphenoxy, 2,6-di-iso-propylphenoxy, 2,6-di-tert-butylphenoxy, 2,4,6-trimethylphenoxy, and 2,4,6-tri-iso-propylphenoxy; furyl, benzofuryl, tetrahydrofuryl, pyranyl, tetrahydropyranyl, acetoxy, pivaloyloxy, benzoyloxy, and trifluoroacetoxy; and groups in which some of the hydrogen atoms in these groups have been replaced with the halogen atoms. Additionally, the oxygen-containing group may be one in which some of the hydrogen atoms in the hydrocarbon group have been substituted with the oxygen-containing group.

The above-exemplified organoaluminum oxy compounds (B-I) may be used alone or in combination of two or more.

<Ionic compound (B-II)>
As the ionic compound (B-II), Lewis acids, ionic compounds, borane compounds, carborane compounds, heteropoly compounds, and isopoly compounds described in, for example, JP-A Nos. 1-501950, 1-502036, 3-179005, 3-179006, 3-207703, 3-207704, and U.S. Pat. No. 5,321,106 can be used without limitation. Among these, the ionic compound (B-II) is preferably a compound represented by the following general formula [b5]:

In formula [b5], Y ⁺ is a hydrogen cation, an oxonium cation, a carbenium cation, an ammonium cation, a phosphonium cation, a cycloheptyltrienyl cation, or a ferrocenium cation.

Examples of the carbenium cation include trisubstituted carbenium cations such as triphenylcarbenium cation, tris(methylphenyl)carbenium cation, and tris(dimethylphenyl)carbenium cation.

Examples of the ammonium cation include trialkylammonium cations such as trimethylammonium cation, triethylammonium cation, tri(n-propyl)ammonium cation, triisopropylammonium cation, tri(n-butyl)ammonium cation, and triisobutylammonium cation; N,N-dialkylanilinium cations such as N,N-dimethylanilinium cation, N,N-diethylanilinium cation, and N,N,2,4,6-pentamethylanilinium cation; and dialkylammonium cations such as diisopropylammonium cation and dicyclohexylammonium cation.

Examples of the phosphonium cation include triarylphosphonium cations such as triphenylphosphonium cation, tris(methylphenyl)phosphonium cation, and tris(dimethylphenyl)phosphonium cation.

Of the above examples, Y ⁺ is preferably a carbenium cation or an ammonium cation, and more preferably a triphenylcarbenium cation, an N,N-dimethylanilinium cation, or a methyldioctadecylammonium cation.

M' is a Group 13 atom of the periodic table, and specific examples include a boron atom and an aluminum atom, with a boron atom being preferred.

Each Q is independently a hydrogen atom, a hydrocarbon group having from 1 to 40 carbon atoms, a halogen atom, a halogen-containing group, or an oxygen-containing group. Multiple Qs may be the same or different and may be bonded to each other to form a ring.

The hydrocarbon group, halogen atom, halogen-containing group, or oxygen-containing group includes those exemplified as R in the general formula [b1], [b2], [b3], or [b4] above, and is preferably an aryl group having 6 to 40 carbon atoms and represented by the following general formula [b6]:

In the formula [b6], * represents a bond to M', and R is selected from the group consisting of a hydrogen atom, a hydrocarbon group having from 1 to 40 carbon atoms, a halogen atom, a halogen-containing group, an oxygen-containing group, a silicon-containing group, a sulfur-containing group, a nitrogen-containing group, and a phosphorus-containing group, and multiple R may be the same or different and may be bonded to each other to form a ring.

Examples of the hydrocarbon group, halogen atom, halogen-containing group, and oxygen-containing group include the same groups as those exemplified as R in formulas [b1], [b2], [b3], and [b4].

Examples of the silicon-containing group include trimethylsilyl, triethylsilyl, tri-isopropylsilyl, diphenylmethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, triphenylsilyl, tris(trimethylsilyl)silyl, trimethylsilylmethyl, chlorodimethylsilyl, chlorodiphenylsilyl, and bromodimethylsilyl. Among the silicon-containing groups, trimethylsilylmethyl, tri-isopropylsilyl, tert-butyldimethylsilyl, chlorodimethylsilyl, and chlorodiphenylsilyl are preferred.

Examples of the sulfur-containing group include a thiol group, a mesyl group (methanesulfonyl group), a phenylsulfonyl group, a tosyl group (p-toluenesulfonyl group), a triflyl group (trifluoromethanesulfonyl group), a nonaflyl group (nonafluorobutanesulfonyl group), a thiophenyl group, a mesylate group (methanesulfonate group), a tosylate group (p-toluenesulfonate group), a triflate group (trifluoromethanesulfonate group), a nonaflate group (nonafluorobutanesulfonate group), a thiophene group, and a benzothiophene group.

Examples of the nitrogen-containing group include amino, cyano, methylamino, dimethylamino, ethylamino, diethylamino, tert-butylamino, di-tert-butylamino, allylamino, diallylamino, benzylamino, dibenzylamino, nitro, pyrrolidinyl, piperidinyl, morpholyl, pyrrolyl, bistriflylimide, pyridinyl, pyrimidinyl, quinolinyl, triazinyl, oxazoline, imidazole, indole, and carbazole groups.

Examples of the phosphorus-containing group include hexafluorophosphate anions.

Of the above examples, R is preferably a halogen atom or a halogen-containing group, and particularly preferably a fluorine atom or a fluorine-containing group. Furthermore, in at least one Q in formula [b5], it is preferable that at least one R in formula [b6] is an oxygen-containing group or a silicon-containing group.

Specific structures of the formula [b5] include triphenylcarbenium tetraphenylborate, triphenylcarbenium tetrakis(pentafluorophenyl)borate, triphenylcarbenium tetrakis(3,5-ditrifluoromethylphenyl)borate, tris(4-methylphenyl)carbenium tetrakis(pentafluorophenyl)borate, tris(3,5-dimethylphenyl)carbenium tetrakis(pentafluorophenyl)borate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, trimethylammonium tetrakis(p-tolyl)borate, trimethylammonium tetrakis(o-tolyl)borate, and tri(n-butyl)ammonium tetrakis(pentafluorophenyl). phenyl)borate, triethylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(2,4-dimethylphenyl)borate, tri(n-butyl)ammonium tetrakis(3,5-dimethylphenyl)borate, tri(n-butyl)ammonium tetrakis(4-trifluoromethylphenyl)borate, tri(n-butyl)ammonium tetrakis(3,5-ditrifluoromethylphenyl)borate, tri(n-butyl)ammonium tetrakis(o-tolyl)borate, dioctadecylmethylammonium tetraphenylborate, dioctadecylmethylammonium tetrakis(p-tolyl)borate, dioctadecylmethylammonium tetrakis(o-tolyl)borate, Dioctadecylmethylammonium tetrakis(pentafluorophenyl)borate, dioctadecylmethylammonium tetrakis(2,4-dimethylphenyl)borate, dioctadecylmethylammonium tetrakis(3,5-dimethylphenyl)borate, dioctadecylmethylammonium tetrakis(4-trifluoromethylphenyl)borate, dioctadecylmethylammonium tetrakis(3,5-ditrifluoromethylphenyl)borate, N,N-dimethylanilinium tetraphenylborate, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetrakis(3,5-ditrifluoromethylphenyl)borate, N,N-diethylanilinium tetraphenylborate, N,N-diethylanilinium tetrakis(pentafluorophenyl)borate Examples include N,N-diethylanilinium tetrakis(3,5-ditrifluoromethylphenyl)borate, N,N-dimethylanilinium tri(pentafluorophenyl)(p-hydroxyphenyl)borate, N,N-dimethylanilinium tri(pentafluorophenyl)(p-chlorodimethylsilyltetrafluorophenyl)borate, N,N-dimethylanilinium tri(pentafluorophenyl)(p-chlorodiphenylsilyltetrafluorophenyl)borate, N,N,2,4,6-pentamethylanilinium tetraphenylborate, N,N,2,4,6-pentamethylanilinium tetrakis(pentafluorophenyl)borate, diisopropylammonium tetrakis(pentafluorophenyl)borate, and dicyclohexylammonium tetraphenylborate.

The ionic compound (B-II) may be used alone or in combination of two or more types.

<Organoaluminum Compound (D)>
In the olefin polymerization catalyst of the present invention, an organoaluminum compound (D) represented by the following general formula [b6] may be used together with the component (B).

R ^a _m Al(OR ^b ) _n H _p X _q … [b6]
In formula [b6], R ^a and R ^b represent a hydrocarbon group having from 1 to 15 carbon atoms and may be the same or different from each other, X represents a halogen atom, m represents an integer of from 1 to 3, n represents an integer of from 0 to 2, p represents an integer of from 0 to 2, q represents an integer of from 0 to 2, and m + n + p + q = 3.

The hydrocarbon group having 1 to 15 carbon atoms is, for example, an alkyl group, a cycloalkyl group, or an aryl group, and specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an isobutyl group, a pentyl group, a hexyl group, an octyl group, a cyclopentyl group, a cyclohexyl group, a phenyl group, and a tolyl group.

Specific examples of the organoaluminum compound (D) include trialkylaluminums such as trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, and tri-2-ethylhexylaluminum; dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, diisopropylaluminum chloride, diisobutylaluminum chloride, and dimethylaluminum bromide; alkylaluminum sesquihalides such as methylaluminum sesquichloride, ethylaluminum sesquichloride, isopropylaluminum sesquichloride, butylaluminum sesquichloride, and ethylaluminum sesquibromide; methylaluminum dichloride, ethylaluminum dichloride, isopropylaluminum sesquibromide, and the like. Examples of suitable aluminum dihalides include alkylaluminum dihalides such as aluminum dichloride and ethylaluminum dibromide; alkylaluminum hydrides such as dimethylaluminum hydride, diethylaluminum hydride, dihydrophenylaluminum hydride, diisopropylaluminum hydride, di-n-butylaluminum hydride, diisobutylaluminum hydride, diisohexylaluminum hydride, diphenylaluminum hydride, dicyclohexylaluminum hydride, di-sec-heptylaluminum hydride, and di-sec-nonylaluminum hydride; and dialkylaluminum alkoxides such as dimethylaluminum ethoxide, diethylaluminum ethoxide, diisopropylaluminum methoxide, and diisobutylaluminum ethoxide.

Of the above, trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, diisobutylaluminum hydride, and diethylaluminum ethoxide are particularly preferred.

<Transition metal compound (C)>
The transition metal compound (C) used in the present invention is not particularly limited, and examples thereof include transition metal compounds used in conventionally known olefin polymerization catalysts, specifically compounds represented by the following general formula (CI):

L _m MX _n ... (C-I)
In the general formula (CI),
M is an atom selected from the group consisting of atoms of Groups 3, 4, 5, 6, 7, 8, 9, 10, and 11 of the periodic table, and lanthanide atoms, and is preferably a transition metal atom of Groups 4 and 10 of the periodic table, specifically a titanium atom, zirconium atom, hafnium atom, palladium atom, or nickel atom.

L is selected from the group consisting of η-bonding cyclic anionic ligands, σ-bonding anionic ligands, and π-bonding neutral ligands, and multiple Ls may be the same or different, and multiple Ls may be connected by substituents within L.

Examples of η-bonding cyclic anionic ligands include cyclopentadienyl groups, indenyl groups, tetrahydroindenyl groups, fluorenyl groups, tetrahydrofluorenyl groups, octahydrofluorenyl groups, and octamethyloctahydrofluorenyl groups, and these ligands may also have other substituents.

The σ-bonding anionic ligand is a compound that contains at least one atom selected from the group consisting of oxygen, boron, nitrogen, phosphorus, sulfur, and selenium, and forms a monovalent σ-bond with M in formula (C-I).

The π-bonding neutral ligand is a compound that contains at least one atom selected from the group consisting of oxygen, boron, nitrogen, phosphorus, sulfur, and selenium and can coordinate to M in the general formula (C-I) via a lone electron pair.

m is an integer of 0 or greater.
n is an integer of 1 to 6, and preferably 1 to 4, satisfying the valence of M.

X is selected from the group consisting of a hydrogen atom, a hydrocarbon group having from 1 to 40 carbon atoms, a halogen atom, a halogen-containing group, a silicon-containing group, an oxygen-containing group, a sulfur-containing group, a nitrogen-containing group, a phosphorus-containing group, and a diene derivative group. When n is 2 or more, multiple Xs may be the same or different and may bond to each other to form a ring. Preferred are hydrogen atoms, halogen atoms, hydrocarbon groups having from 1 to 40 carbon atoms, a silicon-containing group, an oxygen-containing group, and a conjugated diene derivative group.

Examples of the hydrocarbon group, halogen atom, halogen-containing group, silicon-containing group, oxygen-containing group, sulfur-containing group, nitrogen-containing group, and phosphorus-containing group include the same groups as those exemplified as R in formula [b6].

The diene derivative group is a hydrocarbon compound capable of coordinating with M in general formula (C-I) via a lone electron pair, and examples include a 1,3-butadienyl group, an isoprenyl group (2-methyl-1,3-butadienyl group), a piperylenyl group (1,3-pentadienyl group), a 2,4-hexadienyl group, a 1,4-diphenyl-1,3-pentadienyl group, a cyclopentadienyl group, a metallocyclopentenyl group, and a 1,5-cyclooctadienyl group.

Such transition metal compounds (C) are described, for example, in JP-A-61-211307, JP-A-5-148317, JP-A-6-239914, WO 2001/27124, JP-A-2003-206310, JP-A-2004-2259, JP-A-2004-269825, JP-A-2009-143901, and JP-A-2009 -537656, JP 2011-127121, JP 2012-255165, WO 2014/50817, WO 2014/123212, JP 2015-500920, JP 2016-527182, JP 2017-535518, JP 2018-58780, JP 2019-59934 Examples of suitable transition metal compounds include those described in JP-A-5-148317, JP-A-2020-117711, and U.S. Pat. No. 5,272,236, and preferably at least one compound selected from the group consisting of the compound represented by general formula [I] in JP-A-5-148317, the compound represented by general formula (II) in WO 2003/091262, the compound represented by general formula (I) and the compound represented by general formula (XIVb) in JP-A-2003-206310, the compound represented by general formula (I) in JP-A-2012-255165, the compound represented by general formula [2] in JP-A-2020-117711, and the compound represented by general formula (I) in U.S. Pat. No. 5,272,236.

Examples of other transition metal compounds (C) include titanium tetrahalides such as TiCl ₄ , TiBr ₄ , ZrCl ₄ and HfCl ₄ , zirconium tetrahalides, hafnium tetrahalides, alkoxytitanium trihalides such as Ti(OCH ₃ )Cl ₃ , Ti(OC ₂ H ₅ )Cl ₃ , Ti(O-n-C ₄ H ₉ )Cl ₃ , Ti(OC ₂ H ₅ )Br ₃ and Ti(O-iso-C ₄ H ₉ )Br ₃ , Ti(OCH ₃ ) ₂ Cl ₂ , Ti(OC ₂ H ₅ ) ₂ Cl ₂ , Ti(O-C ₄ H ₉ ) ₂ Cl ₂ and Ti(OC ₂ H ₅ ) ₂ Br _2, etc.; monohalogenated trialkoxytitanium compounds such as _Ti ( _OCH3 ) _3Cl , Ti( _OC2H5 )3Cl, Ti(O-n- _C4H9 ) _3Cl , and _Ti ( _OC2H5 ) _{3Br ; and} tetraalkoxytitanium compounds such as _Ti ( _OCH3 ) ₄ , Ti( _OC2H5 )4, Ti(O- _{n- C4H9} ) ₄ , Ti(O-iso- _C4H9 ) ₄ , and Ti(O-2 _- ethylhexyl) _{4 .}

The olefin polymerization catalyst of the present invention, which contains the carbon material (A), the component (B), and the transition metal compound (C), can produce an olefin polymer in which the carbon material is efficiently dispersed with high polymerization activity.

The reason why the present invention is effective is not entirely clear, but the inventors speculate as follows.

Carbon material (A) satisfying the requirements (A-I) and (A-II) has many oxygen-atom-containing functional groups and two-dimensional sheet structures formed by sp ^2- bonded carbon that can contact component (B) and/or transition metal compound (C), allowing component (B) and/or transition metal compound (C) to be immobilized at many locations in the carbon material (A) through chemical bonds or electronic interactions. This presumably enables the olefin polymerization catalyst of the present invention to produce olefin polymers in which the carbon material is efficiently dispersed. Furthermore, surprisingly, when carbon material (A) satisfying the requirements (A-I) and (A-II) is used, higher polymerization activity can be achieved even with a smaller amount of immobilized component (B) and/or transition metal compound (C) than when a conventional carrier such as silica gel is used. This phenomenon is presumably the result of some electronic effect on component (B) and/or transition metal compound (C) due to the two-dimensional sheet structure formed by sp ^2- bonded carbon possessed by the carbon material (A), and it can be said that this is a technology that even a person skilled in the art would not easily discover.

<Method for preparing an olefin polymerization catalyst>
One preferred embodiment of the olefin polymerization catalyst of the present invention is a solid catalyst component (X) prepared by contacting the carbon material (A), the component (B) and the transition metal compound (C).

If the component (B) and the transition metal compound (C) are liquid, they are preferably diluted with an inert solvent. If they are solid, they are preferably dissolved in an inert solvent and brought into contact with the carbon material (A). Examples of inert solvents that can be used include aromatic hydrocarbons such as benzene, toluene, and xylene; saturated aliphatic hydrocarbons such as hexane, heptane, and decane; alicyclic hydrocarbons such as cyclohexane and methylcyclopentane; halogenated hydrocarbons such as ethylene chloride, chlorobenzene, and dichloromethane; and mixtures thereof.

The method for contacting the carbon material (A), component (B), and transition metal compound (C) is not particularly limited as long as the effects of the present invention are achieved. Examples include a method in which an inert solvent containing component (B) or the transition metal compound (C) is added to the carbon material (A) and the pores of the carbon material (A) are impregnated with the component (B) or the transition metal compound (C); a method in which the carbon material (A) is immersed in an inert solvent containing component (B) or the transition metal compound (C) and allowed to stand; a method in which the carbon material (A) is mixed with an inert solvent containing component (B) or the transition metal compound (C) by stirring or the like; and a method in which an inert solvent containing component (B) or the transition metal compound (C) is passed through the carbon material (A). The carbon material (A) may be physically or chemically immobilized on a solid support (including powder, granulated particles, fibers, films, etc.), and heating may be performed during the contact.

Among these, the method of mixing the carbon material (A) with an inert solvent containing the component (B) or the transition metal compound (C) by stirring or the like is preferred. After the contact operation, if necessary, the contact liquid may be allowed to stand and the supernatant removed, or the inert solvent may be removed by filtration or other methods, and the mixture may be washed with the inert solvent if necessary.

The temperature during the heating operation varies depending on the solvent used, but is typically between the freezing point of the solvent and 200°C, preferably 150°C or less. The contact time varies depending on the contact method and temperature, but is typically between 30 seconds and 1,000 hours, preferably between 5 minutes and 120 hours.

In any step of the contact method, the presence of component (G) can further suppress fouling during the polymerization reaction and further improve the particle properties of the resulting polymer. As component (G), a compound having a polar functional group can be used, and nonionic surfactants are preferred, with polyalkylene oxide blocks, higher aliphatic amides, polyalkylene oxides, polyalkylene oxide alkyl ethers, alkyldiethanolamines, polyoxyalkylene alkylamines, glycerin fatty acid esters, and N-acylamino acids being more preferred. These may be used alone or in combination of two or more.

The order of contacting the carbon material (A), the component (B), and the transition metal compound (C) is not particularly limited as long as the effects of the present invention are exhibited.
A step (1-1) of contacting the carbon material (A) with the component (B);
a step (1-2) of contacting the contact product obtained in the step (1-1) with the transition metal compound (C) to obtain a solid catalyst component (X);
a step (2-1) of contacting the carbon material (A) with the component (B);
a step (2-2) of contacting the transition metal compound (C) with the component (B);
and a step (2-3) of contacting the contact product obtained in the step (2-1) with the contact product obtained in the step (2-2) to obtain a solid catalyst component (X). In this case, the component (B) used in the step (2-1) and the component (B) used in the step (2-2) may be the same or different.

In steps (1-1) and (2-1), when component (B) is the organoaluminum oxy compound (B-I), component (B) can be used in an amount of preferably 0.1 mmol to 500 mmol, more preferably 0.2 mmol to 200 mmol, and even more preferably 0.5 mmol to 100 mmol, per 1 g of carbon material (A). When component (B) is the ionic compound (B-II), component (B) can be used in an amount of preferably 0.0001 mmol to 200 mmol, more preferably 0.001 mmol to 100 mmol, and even more preferably 0.002 mmol to 50 mmol, per 1 g of carbon material (A).

In step (2-2), when component (B) is the organoaluminum oxy compound (B-I), component (B) can be used in an amount of preferably 0.1 mmol to 500 mmol, more preferably 0.2 mmol to 200 mmol, and even more preferably 0.5 mmol to 100 mmol, per 1 mmol of the transition metal compound (C). When component (B) is the ionic compound (B-II), component (B) can be used in an amount of preferably 0.1 mmol to 500 mmol, more preferably 0.2 mmol to 200 mmol, and even more preferably 0.5 mmol to 100 mmol, per 1 mmol of the transition metal compound (C).

In steps (1-2) and (2-3), the transition metal compound (C) can be used in an amount of preferably 0.0001 mmol to 1 mmol, more preferably 0.0005 mmol to 0.5 mmol, and even more preferably 0.001 mmol to 0.2 mmol, per 1 g of the carbon material (A).

For the production of olefin polymers, the solid catalyst component (X) may be used in a state of being suspended in an inert hydrocarbon, or in a dried state. Furthermore, the solid catalyst component (X) may be prepolymerized using an olefin, which may be the same as or different from the olefin used in the production of the olefin polymer, before use.

[Production method of olefin polymer]
The method for producing an olefin polymer of the present invention is characterized by comprising a step of polymerizing an olefin in the presence of the above-mentioned olefin polymerization catalyst of the present invention. In the present invention, the term "polymerization" may include not only homopolymerization but also copolymerization such as random copolymerization and block copolymerization.

The olefins polymerized in the present invention include ethylene, α-olefins, and cyclic olefins.

Among these, the α-olefins include linear or branched α-olefins having from 3 to 30 carbon atoms, preferably from 3 to 20 carbon atoms. More specifically, examples include propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. Of these, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, and 3-methyl-1-pentene are preferred, and propylene, 1-butene, 1-hexene, and 4-methyl-1-pentene are more preferred.

Cyclic olefins include those having 3 to 30 carbon atoms, preferably 3 to 20 carbon atoms. More specific examples include cyclopentene, cycloheptene, norbornene, 5-methyl-2-norbornene, tetracyclododecene, and 2-methyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene.

The olefin polymerization step is preferably a step of homopolymerizing ethylene, copolymerizing ethylene with one or more α-olefins having from 3 to 20 carbon atoms, homopolymerizing propylene, copolymerizing propylene with one or more α-olefins having from 4 to 20 carbon atoms, homopolymerizing 4-methyl-1-pentene, or copolymerizing 4-methyl-1-pentene with one or more α-olefins having from 4 to 20 carbon atoms in the presence of the solid catalyst component (X).

In the olefin polymer production method of the present invention, polymerization can be carried out either by liquid phase polymerization, such as suspension polymerization, or by gas phase polymerization. Examples of inert hydrocarbon media used in liquid phase polymerization include aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, decane, dodecane, and kerosene; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane; aromatic hydrocarbons such as benzene, toluene, and xylene; halogenated hydrocarbons such as ethylene chloride, chlorobenzene, and dichloromethane, or mixtures thereof; and the olefin itself can also be used as the solvent.

In the method of the present invention, the lower limit of the temperature for polymerizing olefins is -20°C, preferably 0°C, more preferably 20°C, and particularly preferably 30°C, and the upper limit of the temperature for polymerizing olefins is 200°C, preferably 150°C, more preferably 100°C, and particularly preferably 80°C.

The polymerization pressure in the method of the present invention is typically between atmospheric pressure and 10 MPa, preferably between atmospheric pressure and 5 MPa, and the polymerization reaction can be carried out batchwise, semi-continuously, or continuously.

The method for producing an olefin polymer of the present invention may also be a so-called multi-stage polymerization method in which the polymerization reaction is carried out in two or more stages under different polymerization reaction conditions.

The molecular weight of the resulting olefin polymer can be adjusted by adding hydrogen to the polymerization system or by changing the polymerization temperature.

The organoaluminum compound (D) and/or component (G) can be present in the olefin polymerization process to suppress adhesion (fouling) to the polymerization reactor or improve particle properties.

<Olefin polymer>
[0033] Examples of an embodiment of the olefin polymer obtainable by the method for producing an olefin polymer of the present invention include an ethylene polymer containing ethylene-derived structural units in an amount of preferably from 90 mol% to 100 mol%, more preferably from 95 mol% to 100 mol%; a propylene polymer containing propylene-derived structural units in an amount of preferably from 80 mol% to 100 mol%, more preferably from 90 mol% to 100 mol%; and a 4-methyl-1-pentene polymer containing 4-methyl-1-pentene-derived structural units in an amount of preferably from 80 mol% to 100 mol%, more preferably from 90 mol% to 100 mol%.

The ethylene-based polymer preferably contains a total of 0 mol % to 10 mol %, more preferably 0 mol % to 5 mol %, of structural units derived from α-olefins having 3 to 20 carbon atoms. However, the sum of the content of ethylene-derived structural units and the content of structural units derived from α-olefins having 3 to 20 carbon atoms is taken as 100 mol %.

The propylene-based polymer preferably contains structural units derived from ethylene and an α-olefin having from 4 to 20 carbon atoms in a total amount of from 0 mol % to 20 mol %, more preferably from 0 mol % to 10 mol %. However, the sum of the content of structural units derived from propylene and the content of structural units derived from ethylene and an α-olefin having from 4 to 20 carbon atoms is taken to be 100 mol %.

The 4-methyl-1-pentene polymer preferably contains structural units derived from ethylene and α-olefins other than 4-methyl-1-pentene having 3 to 20 carbon atoms in total in a range of 0 mol % to 20 mol %, more preferably 0 mol % to 10 mol %. However, the sum of the content of structural units derived from 4-methyl-1-pentene and the content of structural units derived from ethylene and α-olefins other than 4-methyl-1-pentene having 3 to 20 carbon atoms is taken as 100 mol %.

Among these polymers, ethylene homopolymer, propylene homopolymer, 4-methyl-1-pentene homopolymer, ethylene/propylene copolymer, ethylene/1-butene copolymer, ethylene/1-hexene copolymer, ethylene/1-octene copolymer, ethylene/4-methyl-1-pentene copolymer, propylene/4-methyl-1-pentene copolymer, 4-methyl-1-pentene/1-decene copolymer, ethylene/propylene/1-butene copolymer, ethylene/propylene/1-octene copolymer, ethylene/propylene/1-hexene copolymer, and ethylene/propylene/4-methyl-1-pentene copolymer are preferred. Also suitable are so-called block copolymers (impact copolymers) obtained by mixing or continuously producing two or more polymers selected from these polymers.

The olefin polymer obtained by the olefin polymer production method preferably contains the carbon material (A) in an amount of 0.005% by weight or more and 25% by weight or less, more preferably 0.01% by weight or more and 10% by weight or less. The carbon material (A) is efficiently dispersed in the olefin polymer, and is expected to have high thermal conductivity, electrical conductivity, and weather resistance.

The present invention will be explained in more detail below based on examples, but the present invention is not limited to these examples in any way.

[Carbon materials]
The following carbon materials (A-1) to (A-6) and (A'-7) to (A'-8) were used as the carbon materials. Each of the carbon materials was dried under reduced pressure at 100°C for 3 hours before use, and then cooled to room temperature under a nitrogen atmosphere before being used in the preparation of solid catalyst component (X).

Carbon material (A-1): XG Sciences Graphene Nanoplatelets xGnP C750
Carbon material (A-2): Reduced Graphene Oxide manufactured by Graphitene
Carbon material (A-3): Nanocyl Multi-Walled Carbon nanotubes NANOCYL NC3101
Carbon material (A-4): IoLiTec Multi-Walled Carbon Nanotubes -OH functionalized CP-0069-SG
Carbon material (A-5): Toyo Tanso Co., Ltd. Porous carbon CNovel MJ(4)010
Carbon material (A-6): Nippon Graphite Co., Ltd. High-purity graphite powder SP-270
Carbon material (A'-7): Graphitene Nanocarbon Platelets - Powder
Carbon material (A'-8): Southwest Nanotechnologies Single Walled Carbon nanotubes Signis SG65i

<Oxygen content>
The oxygen content of the carbon material was determined by X-ray photoelectron spectroscopy (XPS) ("AXIS-NOVA" manufactured by KRATOS). The sample was dried under reduced pressure at 100°C for 3 hours, then handled in a nitrogen atmosphere and measured using a monochromated AlKα X-ray source. Charge correction and neutralization were performed during the measurement. The oxygen atom concentration was determined from the peak area of the O1s narrow spectrum, and the carbon atom concentration was determined from the peak area of the C1s narrow spectrum, and the molar ratio of oxygen atoms to carbon atoms was calculated. The results are shown in Table 1.

≪Specific surface area≫
The specific surface area of the carbon material was measured by measuring the adsorption/desorption isotherm using a nitrogen gas adsorption method (Microtrac-Bell "BELSORP-max") at liquid nitrogen temperature. The specific surface area was determined using the BET multipoint method as an analytical method. The analytical results are shown in Table 1.

[Component (B)]
As component (B), the following components (B-1) to (B-4) were used.
Component (B-1): methylaluminoxane (MAO)
Component (B-2): Modified methylaluminoxane (MMAO-3A)
Component (B-3): A compound represented by the following formula (B-3) Component (B-4): A compound represented by the following formula (B-4)

[Transition metal compound]
As the transition metal compounds, transition metal compounds (C-1) to (C-10) represented by the following formulas (C-1) to (C-10) were used.

[Preparation of solid catalyst component (X)]
<Preparation Example 1>
In a 30 mL Schlenk flask that had been thoroughly purged with nitrogen, 200 mg of carbon material (A-1) and 19.5 mL of toluene were added, and stirring was initiated using a rotor. To this suspension, 0.50 mL of a toluene solution of component (B-1) (1.0 mol/L in terms of Al atoms) was added as component (B), and stirring was continued at room temperature for 2 hours, after which stirring was stopped and the mixture was allowed to stand. The supernatant was removed by decantation, and the supernatant was analyzed. As a result, the Al concentration in the supernatant was below the lower limit of quantitation (less than 0.19 mmol/L). After further washing with toluene twice, 2.0 mL of a toluene solution of transition metal compound (C-1) (1.0 mmol/L in terms of Zr) was added, and the mixture was further stirred at room temperature for 30 minutes to prepare a slurry of solid catalyst component (X-1) with a solid concentration of carbon material (A-1) of 10.0 g/L.

<Preparation Example 2>
In a 30 mL Schlenk flask that had been thoroughly purged with nitrogen, 200 mg of carbon material (A-2) and 19.2 mL of toluene were added, and stirring was initiated using a rotor. To this suspension, 0.80 mL of a toluene solution of component (B-1) (1.0 mol/L in terms of Al atoms) was added as component (B), and stirring was continued at room temperature for 2 hours, after which stirring was stopped and the mixture was allowed to stand. The supernatant was removed by decantation, and the supernatant was analyzed. As a result, the Al concentration in the supernatant was below the lower limit of quantitation (less than 0.19 mmol/L). After further washing with toluene twice, 2.0 mL of a toluene solution of transition metal compound (C-1) (1.0 mmol/L in terms of Zr) was added, and the mixture was further stirred at room temperature for 30 minutes to prepare a slurry of solid catalyst component (X-2) with a solid concentration of carbon material (A-2) of 10.0 g/L.

<Preparation Examples 3 to 6>
Slurries of solid catalyst components (X-3) to (X-6) were prepared in the same manner as in Preparation Example 1, except that carbon materials (A-3) to (A-6) were used instead of carbon material (A-1).

<Preparation Example 7>
200 mg of carbon material (A'-7) and 19.5 mL of toluene were added to a 30 mL Schlenk flask that had been thoroughly purged with nitrogen, and stirring was initiated using a rotor. To this suspension, 0.50 mL of a toluene solution of component (B-1) (1.0 mol/L in terms of Al atoms) was added as component (B), and stirring was continued at room temperature for 2 hours, after which stirring was stopped and the mixture was allowed to stand. The supernatant was removed by decantation, and the supernatant was analyzed. The Al concentration in the supernatant was found to be 24 mmol/L. After further washing with toluene twice, 2.0 mL of a toluene solution of transition metal compound (C-1) (1.0 mmol/L in terms of Zr) was added, and the mixture was further stirred at room temperature for 30 minutes to prepare a slurry of solid catalyst component (X-7) with a solid concentration of carbon material (A'-7) of 10.0 g/L.

<Preparation Example 8>
A slurry of a solid catalyst component (X-8) was prepared in the same manner as in Preparation Example 7, except that the carbon material (A'-8) was used instead of the carbon material (A'-7).

<Preparation Example 9>
Into a 30 mL Schlenk flask that had been thoroughly purged with nitrogen, 200 mg of silica gel (particle size: 70 μm, specific surface area: 340 m ² /g, pore volume: 1.3 cm ³ /g) and 19.0 mL of toluene were added, and stirring was started using a rotor. To this suspension, 1.0 mL of a toluene solution of component (B-1) (1.0 mol/L in terms of Al atoms) was added as component (B), and stirring was continued at room temperature for 2 hours, after which stirring was stopped and the mixture was allowed to stand. The supernatant was removed by decantation, and the supernatant was analyzed. As a result, the Al concentration in the supernatant was found to be 2.0 mmol/L. After further washing with toluene twice, 4.0 mL of a toluene solution of transition metal compound (C-1) (1.0 mmol/L in terms of Zr) was added, and stirring was continued for another 30 minutes at room temperature to prepare a slurry of solid catalyst component (X-9) with a silica gel solid concentration of 10.0 g/L.

<Preparation Example 10>
In a 30 mL Schlenk flask that had been thoroughly purged with nitrogen, 200 mg of carbon material (A-1) and 19.5 mL of toluene were added, and stirring was initiated using a rotor. To this suspension, 0.50 mL of a hexane solution of component (B-2) (1.0 mol/L in terms of Al atoms) was added as component (B), and stirring was continued at room temperature for 2 hours, after which stirring was stopped and the mixture was allowed to stand. The supernatant was removed by decantation, and the supernatant was analyzed. As a result, the Al concentration in the supernatant was below the lower limit of quantitation (less than 0.19 mmol/L). After further washing with toluene twice, 2.0 mL of a toluene solution of transition metal compound (C-1) (1.0 mmol/L in terms of Zr) was added, and the mixture was further stirred at room temperature for 30 minutes to prepare a slurry of solid catalyst component (X-10) with a solid concentration of carbon material (A-1) of 10.0 g/L.

<Preparation Example 11>
200 mg of carbon material (A-1) and 8.0 mL of toluene were added to a 30 mL Schlenk flask that had been thoroughly purged with nitrogen, and stirring was initiated using a rotor. To this suspension, 12.0 mL of a toluene solution of component (B-3) (1.0 mmol/L in terms of B atoms) was added as component (B). Stirring was continued at room temperature for 2 hours, after which stirring was stopped and the mixture was allowed to stand. The supernatant was removed by decantation, and the mixture was further washed twice with toluene. 3.0 mL of a toluene solution (1.0 mmol/L in terms of Zr, 30 mmol/L in terms of Al) containing a mixture of transition metal compound (C-1) and triisobutylaluminum was added thereto, and stirring was continued for 30 minutes at room temperature to prepare a slurry of solid catalyst component (X-11) with a solid concentration of carbon material (A-1) of 10.0 g/L.

<Preparation Example 12>
200 mg of carbon material (A-1) and 19.8 mL of toluene were added to a 30 mL Schlenk flask that had been thoroughly purged with nitrogen, and stirring was initiated using a rotor. 0.20 mL of a toluene solution of triisobutylaluminum (1.0 mol/L in terms of Al) was added to this suspension, and stirring was continued at room temperature for 30 minutes, after which stirring was stopped and the mixture was allowed to stand. The supernatant was removed by decantation, and the mixture was further washed twice with toluene. Next, 12.0 mL of a toluene solution of component (B-4) (1.0 mmol/L in terms of B atoms) was added as component (B), and stirring was continued at room temperature for 1 hour, after which stirring was stopped and the mixture was allowed to stand. The supernatant was removed by decantation, and the mixture was further washed twice with toluene. To this was added 3.0 mL of a toluene solution (1.0 mmol/L in terms of Zr, 30 mmol/L in terms of Al) containing a mixture of the transition metal compound (C-1) and triisobutylaluminum, and the mixture was further stirred at room temperature for 30 minutes to prepare a slurry of a solid catalyst component (X-12) having a solid content concentration of the carbon material (A-1) of 10.0 g/L.

<Preparation Example 13>
200 mg of carbon material (A-1) and 19.8 mL of toluene were added to a 30 mL Schlenk flask that had been thoroughly purged with nitrogen, and stirring was initiated using a rotor. 0.20 mL of a toluene solution of triisobutylaluminum (1.0 mol/L in terms of Al) was added to this suspension, and stirring was continued at room temperature for 30 minutes, after which stirring was stopped and the mixture was allowed to stand. The supernatant was removed by decantation, and the mixture was further washed twice with toluene. 3.0 mL of a toluene solution of transition metal compound (C-1) (1.0 mmol/L in terms of Zr) was added to this, and stirring was continued for another 30 minutes at room temperature to prepare a slurry of solid catalyst component (X-13) with a solid concentration of carbon material (A-1) of 10.0 g/L.

<Preparation Examples 14 to 16>
Slurries of solid catalyst components (X-14) to (X-16) were prepared in the same manner as in Preparation Example 1, except that transition metal compounds (C-2) to (C-4) were used instead of the transition metal compound (C-1).

<Preparation Example 17>
200 mg of carbon material (A-1) and 19.8 mL of toluene were added to a 30 mL Schlenk flask that had been thoroughly purged with nitrogen, and stirring was initiated using a rotor. 0.20 mL of a toluene solution of triethylaluminum (1.0 mol/L in terms of Al) was added to this suspension, and stirring was continued at room temperature for 30 minutes, after which stirring was stopped and the mixture was allowed to stand. The supernatant was removed by decantation, and the mixture was further washed twice with toluene. Next, 12.0 mL of a toluene solution of component (B-4) (1.0 mmol/L in terms of B atoms) was added as component (B), and stirring was continued at room temperature for 1 hour, after which stirring was stopped and the mixture was allowed to stand. The supernatant was removed by decantation, and the mixture was further washed twice with toluene. To this was added 3.0 mL of a toluene solution of the transition metal compound (C-5) (1.0 mmol/L in terms of Ti), and the mixture was further stirred at room temperature for 30 minutes to prepare a slurry of a solid catalyst component (X-17) having a solid content concentration of the carbon material (A-1) of 10.0 g/L.

<Preparation Example 18>
In a 30 mL Schlenk flask that had been thoroughly purged with nitrogen, 200 mg of carbon material (A-1) and 19.5 mL of toluene were added, and stirring was started using a rotor. To this suspension, 0.50 mL of a toluene solution of component (B-1) (1.0 mol/L in terms of Al atoms) was added as component (B), and stirring was continued at room temperature for 2 hours, after which stirring was stopped and the mixture was allowed to stand. The supernatant was removed by decantation, and the mixture was further washed twice with toluene. 0.050 mL of a toluene solution of transition metal compound (C-6) (0.10 mol/L in terms of Ti) was added, and the mixture was further stirred at room temperature for 30 minutes to prepare a slurry of solid catalyst component (X-18) with a solid concentration of carbon material (A-1) of 10.0 g/L.

<Preparation Examples 19 to 21>
Slurries of solid catalyst components (X-19) to (X-21) were prepared in the same manner as in Preparation Example 1, except that the transition metal compounds (C-7) to (C-9) were used instead of the transition metal compound (C-1).

<Preparation Example 22>
In a 30 mL Schlenk flask that had been thoroughly purged with nitrogen, 200 mg of carbon material (A-4) and 19.5 mL of toluene were added, and stirring was initiated using a rotor. To this suspension, 0.50 mL of a toluene solution of component (B-1) (1.0 mol/L in terms of Al atoms) was added as component (B), and stirring was continued at room temperature for 2 hours, after which stirring was stopped and the mixture was allowed to stand. The supernatant was removed by decantation, and the mixture was further washed twice with toluene. 0.10 mL of a toluene solution of transition metal compound (C-9) (0.02 mol/L in terms of Zr) was added, and the mixture was further stirred at room temperature for 30 minutes to prepare a slurry of solid catalyst component (X-22) with a solid concentration of carbon material (A-4) of 10.0 g/L.

<Preparation Example 23>
In a 30 mL Schlenk flask that had been thoroughly purged with nitrogen, 200 mg of carbon material (A-3) and 19.5 mL of toluene were added, and stirring was initiated using a rotor. To this suspension, 0.50 mL of a toluene solution of component (B-1) (1.0 mol/L in terms of Al atoms) was added as component (B), and stirring was continued at room temperature for 2 hours, after which stirring was stopped and the mixture was allowed to stand. The supernatant was removed by decantation, and the mixture was further washed twice with toluene. 0.050 mL of a toluene solution of transition metal compound (C-10) (0.10 mol/L in terms of Zr) was added, and the mixture was further stirred at room temperature for 30 minutes to prepare a slurry of solid catalyst component (X-23) with a solid concentration of carbon material (A-3) of 10.0 g/L.

<Metal concentration in the supernatant during preparation of solid catalyst component (X)>
The metal (Al) concentration in the supernatant liquid during the preparation of the solid catalyst component (X) was determined by ICP atomic emission spectrometry (ICP-AES) (ICPS-8100, manufactured by Shimadzu Corporation).

[Production of olefin polymer]
Example 1
500 mL of heptane was added to a 1-liter SUS autoclave reactor that had been thoroughly purged with nitrogen under a nitrogen atmosphere, and ethylene was then passed through to saturate the reactor with ethylene. Next, 0.375 mL of a decane solution of triisobutylaluminum (1.0 mol/L in terms of Al) and an amount of slurry equivalent to 30 mg of the solid content of the carbon material (A-1) were extracted from the slurry of the solid catalyst component (X-1) obtained in Preparation Example 1 and charged into the reactor. The temperature and pressure were then increased to 80°C and 0.8 MPaG using ethylene, and a polymerization reaction was carried out for 90 minutes at a rotation speed of 350 rpm. After completion of the reaction, the contents of the reactor were filtered and dried under reduced pressure at 80°C for 10 hours, yielding 94.3 g of an olefin polymer. The weight-average molecular weight (Mw) of the resulting olefin polymer was 2,450,000.

<Examples 2 to 6>
Polymerization reactions were carried out in the same manner as in Example 1, except that slurries of solid catalyst components (X-2) to (X-6) obtained in Preparation Examples 2 to 6 were used instead of solid catalyst component (X-1), and the amounts of the solid carbon material shown in Table 1 were charged into the reactor. After completion of the reaction, the contents in the reactor were filtered and dried under reduced pressure at 80°C for 10 hours, yielding the amounts of olefin polymers shown in Table 1.

<Comparative Examples 1 to 3>
Polymerization reactions were carried out in the same manner as in Example 1, except that slurries of solid catalyst components (X-7) to (X-9) obtained in Preparation Examples 7 to 9 were used instead of solid catalyst component (X-1), and the amounts of carbon material or silica gel solid content shown in Table 1 were charged into the reactor. After completion of the reaction, the contents in the reactor were filtered and dried under reduced pressure at 80°C for 10 hours, yielding the amounts of olefin polymers shown in Table 1.

The carbon material (A) constituting the olefin polymerization catalyst of the example has both a high specific surface area and a high oxygen content, and it can be seen that a larger amount of olefin polymer can be obtained compared to a carbon material with a low specific surface area or oxygen content, or a comparative example using silica gel, which is commonly used as a support for olefin polymerization catalysts.

<Examples 7 to 9>
A polymerization reaction was carried out in the same manner as in Example 1, except that the slurries of the solid catalyst components (X-10) to (X-12) obtained in Preparation Examples 10 to 12 were used instead of the solid catalyst component (X-1), and the amount of the carbon material (A) solid content shown in Table 2 was charged into the reactor. After completion of the reaction, the content in the reactor was filtered and dried under reduced pressure at 80°C for 10 hours, thereby obtaining the amount of olefin polymer shown in Table 2.

<Comparative Example 4>
A polymerization reaction was carried out in the same manner as in Example 1, except that the slurry of solid catalyst component (X-13) obtained in Preparation Example 13 was used instead of solid catalyst component (X-1), and the amount of carbon material (A) solid content shown in Table 2 was charged into the reactor. After completion of the reaction, the content in the reactor was filtered and dried under reduced pressure at 80°C for 10 hours, thereby obtaining an olefin polymer in the amount shown in Table 2.

It can be seen that the examples using component (B) yielded more olefin polymer than the comparative examples not using component (B).

Example 10
500 mL of heptane was added to a 1-liter SUS autoclave reactor that had been thoroughly purged with nitrogen under a nitrogen atmosphere, and ethylene was then passed through to saturate the reactor with ethylene. Next, 0.375 mL of a decane solution of triisobutylaluminum (1.0 mol/L in terms of Al) and an amount of slurry equivalent to 20 mg of the solid content of the carbon material (A-1) were extracted from the slurry of the solid catalyst component (X-14) obtained in Preparation Example 14 and charged into the reactor. Thereafter, the temperature and pressure were increased to 80°C and 0.8 MPaG using ethylene, and a polymerization reaction was carried out for 90 minutes at a rotation speed of 350 rpm. After completion of the reaction, the contents of the reactor were filtered and dried under reduced pressure at 80°C for 10 hours, yielding 48.8 g of an olefin polymer. The weight-average molecular weight (Mw) of the resulting olefin polymer was 2,110,000.

Example 11
500 mL of heptane was added to a 1-liter SUS autoclave reactor that had been thoroughly purged with nitrogen under a nitrogen atmosphere, and ethylene was then passed through to saturate the reactor with ethylene. Next, 0.375 mL of a decane solution of triisobutylaluminum (1.0 mol/L in terms of Al) and an amount of slurry equivalent to 50 mg of the solid content of the carbon material (A-1) were extracted from the slurry of the solid catalyst component (X-15) obtained in Preparation Example 15 and charged into the reactor. Thereafter, the temperature and pressure were increased to 50°C and 0.8 MPaG using ethylene, and a polymerization reaction was carried out for 90 minutes at a rotation speed of 350 rpm. After completion of the reaction, the contents of the reactor were filtered and dried under reduced pressure at 80°C for 10 hours, yielding 12.5 g of an olefin polymer. The weight-average molecular weight (Mw) of the resulting olefin polymer was 3,780,000.

Example 12
500 mL of heptane was added to a 1-liter SUS autoclave reactor that had been thoroughly purged with nitrogen under a nitrogen atmosphere, and then ethylene was passed through to saturate the reactor with ethylene. Next, 0.375 mL of a decane solution of triisobutylaluminum (1.0 mol/L in terms of Al) and an amount of slurry equivalent to 50 mg of the solid content of the carbon material (A-1) were extracted from the slurry of the solid catalyst component (X-16) obtained in Preparation Example 16 and charged into the reactor. Thereafter, the temperature and pressure were increased to 80 ° C. and 0.8 MPaG using ethylene, and a polymerization reaction was carried out for 90 minutes at a rotation speed of 350 rpm. After completion of the reaction, the contents of the reactor were filtered and dried under reduced pressure at 80 ° C. for 10 hours, yielding 28.4 g of an olefin polymer.

Example 13
500 mL of heptane was added to a 1-liter SUS autoclave reactor that had been thoroughly purged with nitrogen under a nitrogen atmosphere, and ethylene was then passed through to saturate the reactor with ethylene. Next, 0.375 mL of a decane solution of triisobutylaluminum (1.0 mol/L in terms of Al) and an amount of slurry equivalent to 30 mg of the solid content of the carbon material (A-1) were extracted from the slurry of the solid catalyst component (X-17) obtained in Preparation Example 17 and charged into the reactor. Thereafter, the temperature and pressure were increased to 80°C and 0.8 MPaG using ethylene, and a polymerization reaction was carried out for 90 minutes at a rotation speed of 350 rpm. After completion of the reaction, the contents of the reactor were filtered and dried under reduced pressure at 80°C for 10 hours, yielding 91.3 g of an olefin polymer. The weight-average molecular weight (Mw) of the resulting olefin polymer was 2,460,000.

Example 14
500 mL of heptane was added to a 1-liter SUS autoclave reactor that had been thoroughly purged with nitrogen under a nitrogen atmosphere, and ethylene was then passed through to saturate the reactor with ethylene. Next, 0.375 mL of a decane solution of triethylaluminum (1.0 mol/L in terms of Al) and an amount of slurry equivalent to 50 mg of the solid content of the carbon material (A-1) were extracted from the slurry of the solid catalyst component (X-18) obtained in Preparation Example 18 and charged into the reactor. Thereafter, the temperature and pressure were increased to 80°C and 0.8 MPaG using ethylene, and a polymerization reaction was carried out for 90 minutes at a rotation speed of 350 rpm. After completion of the reaction, the contents of the reactor were filtered and dried under reduced pressure at 80°C for 10 hours, yielding 8.53 g of an olefin polymer. The weight-average molecular weight (Mw) of the resulting olefin polymer was 4,230,000.

Example 15
500 mL of heptane was added to a 1-liter SUS autoclave reactor that had been thoroughly purged with nitrogen under a nitrogen atmosphere, and ethylene was then passed through to saturate the reactor with ethylene. Next, 0.375 mL of a decane solution of triisobutylaluminum (1.0 mol/L in terms of Al) and an amount of slurry equivalent to 50 mg of the solid content of the carbon material (A-1) were extracted from the slurry of the solid catalyst component (X-19) obtained in Preparation Example 19 and charged into the reactor. Thereafter, the temperature and pressure were increased to 60°C and 0.8 MPaG with ethylene, and a polymerization reaction was carried out for 90 minutes at a rotation speed of 350 rpm. After completion of the reaction, the contents of the reactor were filtered and dried under reduced pressure at 80°C for 10 hours, yielding 12.4 g of an olefin polymer. The weight-average molecular weight (Mw) of the resulting olefin polymer was 138,000 and the melting point was 123°C.

Example 16
500 mL of heptane was added to a 1-liter SUS autoclave reactor that had been thoroughly purged with nitrogen under a nitrogen atmosphere, and then ethylene was passed through to saturate the reactor with ethylene. Next, 10 mL of 1-hexene, 0.375 mL of a decane solution of triisobutylaluminum (1.0 mol/L in terms of Al), and an amount of slurry equivalent to 20 mg of the solid content of the carbon material (A) from the slurry of the solid catalyst component (X-20) obtained in Preparation Example 20 were extracted and charged into the reactor. Thereafter, the temperature and pressure were increased to 80°C and 0.8 MPaG using ethylene, and a polymerization reaction was carried out for 60 minutes at a rotation speed of 350 rpm. After completion of the reaction, the contents of the reactor were filtered and dried under reduced pressure at 80°C for 10 hours, yielding 17.2 g of an olefin polymer. The weight-average molecular weight (Mw) of the obtained olefin polymer was 431,000 and the melting point was 124°C.

Example 17
500 mL of heptane was added to a 1-liter SUS autoclave reactor that had been thoroughly purged with nitrogen under a nitrogen atmosphere, and then propylene was passed through to saturate the reactor with propylene. Next, 0.375 mL of a decane solution of triisobutylaluminum (1.0 mol/L in terms of Al) and an amount of slurry equivalent to 80 mg of the solid content of the carbon material (A) were extracted from the slurry of the solid catalyst component (X-21) obtained in Preparation Example 21 and charged into the reactor. Thereafter, 100 mL of hydrogen was added, and the temperature and pressure were raised to 70 ° C. and 0.5 MPaG with propylene, and a polymerization reaction was carried out for 60 minutes at a rotation speed of 350 rpm. After completion of the reaction, the contents of the reactor were filtered and dried under reduced pressure at 80 ° C. for 10 hours, yielding 15.4 g of an olefin polymer. The weight-average molecular weight (Mw) of the resulting olefin polymer was 202,000 and the melting point was 161 ° C.

Example 18
A 1-liter glass reactor that had been thoroughly purged with nitrogen was charged with 400 mL of 4-methyl-1-pentene under a nitrogen atmosphere, and the temperature was raised to 40°C. Then, while hydrogen was passed through at 0.50 L/hr, 0.20 mL of a decane solution of triisobutylaluminum (1.0 mol/L in terms of Al) and a slurry equivalent to 80 mg of the solid content of the carbon material (A) were extracted from the slurry of the solid catalyst component (X-22) obtained in Preparation Example 22 and charged into the reactor, where a polymerization reaction was carried out for 60 minutes at a rotation speed of 600 rpm. After completion of the reaction, the contents of the reactor were filtered and dried under reduced pressure at 80°C for 10 hours, yielding 5.45 g of an olefin polymer. The weight-average molecular weight (Mw) of the resulting olefin polymer was 361,000.

Example 19
500 mL of heptane was added to a 1-liter SUS autoclave reactor that had been thoroughly purged with nitrogen under a nitrogen atmosphere, and ethylene was then passed through to saturate the reactor with propylene. Next, 0.375 mL of a decane solution of triisobutylaluminum (1.0 mol/L in terms of Al) and an amount of slurry equivalent to 20 mg of the solid content of the carbon material (A) were extracted from the slurry of the solid catalyst component (X-23) obtained in Preparation Example 23 and charged into the reactor. Thereafter, using an ethylene/1-butene mixed gas with a 1-butene concentration of 1.0 vol%, the temperature and pressure were increased to 80°C and 0.8 MPaG, and a polymerization reaction was carried out for 60 minutes at a rotation speed of 350 rpm. After completion of the reaction, the contents of the reactor were filtered and dried under reduced pressure at 80°C for 10 hours, yielding 19.4 g of an olefin polymer. The weight average molecular weight (Mw) of the resulting olefin polymer was 754,000 and the melting point was 114°C.

The examples using various transition metal compounds (C-1) to (C-10) demonstrate that, regardless of the type of transition metal compound, a larger number of olefin polymers can be obtained by using a specific carbon material (A).

≪Weight average molecular weight (Mw)≫
The weight average molecular weight (Mw) of the olefin polymer was determined by gel permeation chromatography (GPC) using a Waters "Alliance GPC 2000" gel permeation chromatograph (high-temperature size exclusion chromatograph) under the following operating conditions:

Analysis software: Chromatography Data System Empower (Waters)
Column: TSKgel GMH6-HT x 2 + TSKgel GMH6-HT x 2
(Inner diameter 7.5 mm x length 30 cm, Tosoh Corporation)
Mobile phase: o-dichlorobenzene Detector: differential refractometer (built-in)
Column temperature: 140°C
Flow rate: 1.0mL/min
Injection volume: 400μL
Sampling time interval: 1 second Sample concentration: 0.15% (w/v)
Molecular weight calibration: Monodisperse polystyrene (Tosoh Corporation) / molecular weight 495 to 20.6 million

<Melting point (Tm)>
Using an SII RDC220 differential scanning calorimeter, approximately 5 mg of sample was heated from 30°C to 200°C at a heating rate of 50°C/min under a nitrogen atmosphere and held at that temperature for 10 minutes. The sample was then cooled to 30°C at a heating rate of 10°C/min, held at that temperature for 5 minutes, and then heated to 200°C at a heating rate of 10°C/min. The endothermic peak observed during this second heating was taken as the melting peak, and the temperature at which the melting peak appeared was determined as the melting point (Tm).

Claims (7)

A carbon material (A) that satisfies the following requirements (AI) and (A-II);
At least one component (B) selected from the group consisting of the following (BI) and (B-II):
and a transition metal compound (C) represented by the following general formula (CI):
(A-I) The oxygen atom/carbon atom molar ratio measured by X-ray photoelectron spectroscopy (XPS) is 0.018 or more and 0.400 or less;
(A-II) The specific surface area measured by the BET multipoint method is 100 m ² /g or more and 5000 ^{m 2} /g or less;
(B-I) Organoaluminum oxy compounds;
(B-II) a compound that reacts with the transition metal compound (C) to form an ion pair;
L _m MX _n ... (C-I)
[In general formula (C-I), M is an atom selected from the group consisting of atoms of Groups 3, 4, 5, 6, 7, 8, 9, 10, and 11 of the periodic table, and lanthanide atoms;
L is selected from the group consisting of η-bonding cyclic anionic ligands, σ-bonding anionic ligands, and π-bonding neutral ligands, and multiple Ls may be the same or different, and multiple Ls may be connected via a substituent in L;
m is an integer of 0 or greater,
n is an integer of 1 to 6 that satisfies the valence of M;
X is selected from a hydrogen atom, a halogen atom, a hydrocarbon group, a halogen-containing group, a silicon-containing group, an oxygen-containing group, a sulfur-containing group, a nitrogen-containing group, a phosphorus-containing group, and a diene derivative group, and when n is 2 or more, multiple Xs may be the same or different and may be bonded to each other to form a ring. The olefin polymerization catalyst according to claim 1, wherein the oxygen atom/carbon atom molar ratio in requirement (A-I) is 0.020 or more and 0.250 or less. 3. The olefin polymerization catalyst according to claim 1, wherein the specific surface area in the requirement (A-II) is 150 ^{m 2} /g or more and 3,000 ^{m 2} /g or less. The olefin polymerization catalyst according to any one of claims 1 to 3, wherein the carbon material (A) comprises at least one material selected from the group consisting of carbon nanotubes, graphene, fullerene, graphite, and activated carbon. The olefin polymerization catalyst according to any one of claims 1 to 4, wherein M in general formula (C-I) is a Group 4 transition metal atom of the periodic table. A method for producing an olefin polymer, comprising the step of polymerizing an olefin in the presence of the olefin polymerization catalyst described in any one of claims 1 to 5. The method for producing an olefin polymer according to claim 6, wherein the step of polymerizing an olefin is a step of homopolymerizing ethylene or propylene, or a step of copolymerizing ethylene with a linear or branched α-olefin having 3 to 30 carbon atoms.