JP7483465B2 - Method for producing ethylene polymer - Google Patents

Description

The present invention relates to a method for producing an ethylene-based polymer.

In recent years, several methods have been disclosed for producing ethylene-based polymers containing ethylene homopolymers or ethylene-α-olefin copolymers with relatively small molecular weights and ethylene homopolymers or ethylene-α-olefin copolymers with relatively large molecular weights by continuous polymerization using single-site catalysts or catalysts with single-site catalysts supported on carriers, which are easy to control the composition distribution (see, for example, Patent Documents 1 to 3).

International Publication No. 2004/083265 International Publication No. 2006/019147 International Publication No. 2008/087945

According to the study by the present inventors, it was found that when an ethylene-based polymer is produced, for example, by a slurry polymerization method using continuous multi-stage polymerization, the molded article formed from the obtained ethylene-based polymer may have a poor appearance.

The present invention aims to provide a method for producing an ethylene-based polymer that can easily form a molded product with good appearance when producing an ethylene-based polymer by a slurry polymerization method using a single-site catalyst in continuous multi-stage polymerization.

The present inventors have conducted extensive research to solve the above problems. As a result, they have found that the defects in product appearance are related to the molecular weight of the ethylene polymer polymerized in each stage of continuous multi-stage polymerization, particularly the molecular weight of the ethylene polymer in the polymerization of a high molecular weight component. They have also found that the above problems can be solved by using an olefin polymerization catalyst containing a specific transition metal compound and a bridged metallocene compound in a specific continuous multi-stage polymerization, and have completed the present invention.
The present invention relates to, for example, the following [1] to [4].

[1] A method for continuously producing an ethylene polymer (E),
a step (1) of producing an ethylene polymer (e1) having an intrinsic viscosity [η] of 0.5 to 1.5 dl/g as measured in decalin at 135° C. by a slurry polymerization method in the presence of an olefin polymerization catalyst comprising a transition metal compound (A1) represented by formula (I) and a bridged metallocene compound (A2) represented by formula (IV), in an amount of 20 to 80 mass % of the finally obtained ethylene polymer (E);
a step (2) of producing an ethylene polymer (e2) having an intrinsic viscosity [η] of 3.0 to 10.0 dl/g as measured in decalin at 135° C. by a slurry polymerization method in the presence of the ethylene polymer (e1) obtained in the step (1), in an amount of 20 to 80 mass% of the finally obtained ethylene polymer (E);
Including,
The slurry containing the ethylene polymer (e1) and the olefin polymerization catalyst obtained in the step (1) is continuously supplied to the step (2).
A method for producing an ethylene polymer (E).

［式（Ｉ）中、
Ｍは、周期表第４族の遷移金属原子であり、
ｍは、１～４の整数であり、
Ｒ¹～Ｒ⁵はそれぞれ独立に、水素原子、ハロゲン原子、炭化水素基またはヘテロ原子含有基であり、これらのうちの２個以上が互いに連結して環を形成していてもよく、ｍが２以上の場合、Ｒ¹～Ｒ⁵で示される基のうち少なくとも２個の基が連結されていてもよく、
Ｒ⁶は、式Ｃ_n'Ｈ_2n'+1（ｎ’は１～８の整数である）、式（ＩＩ）または式（ＩＩＩ）で表される基であり、
ｊは、Ｍの価数を満たす数であり、
Ｘは、水素原子、ハロゲン原子、炭化水素基またはヘテロ原子含有基であり、ｊが２以上の場合、Ｘで示される複数の基は互いに同一でも異なっていてもよく、またＸで示される複数の基は互いに結合して環を形成してもよい。］

[In formula (I),
M is a transition metal atom of Group 4 of the periodic table;
m is an integer from 1 to 4,
R ¹ to R ⁵ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing group, two or more of which may be linked to each other to form a ring, and when m is 2 or more, at least two of the groups represented by R ¹ to R ⁵ may be linked to each other;
R ⁶ is a group represented by the formula C _n' H _2n'+1 (n' is an integer from 1 to 8), the formula (II) or the formula (III);
j is a number that satisfies the valence of M;
X is a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing group, and when j is 2 or more, the groups represented by X may be the same or different, and the groups represented by X may be bonded to each other to form a ring.

［式（ＩＩ）中、
Ｒ⁷およびＲ¹¹は、水素原子であり、
Ｒ⁸～Ｒ¹⁰はそれぞれ独立に、水素原子、ハロゲン原子、炭化水素基またはヘテロ原子含有基であり、Ｒ⁸～Ｒ¹⁰のうちの２個以上が互いに連結して環を形成していてもよく、
黒丸（●）は、式（Ｉ）中の窒素原子との結合点である。］

[In the formula (II),
R ⁷ and R ¹¹ are hydrogen atoms;
R ⁸ to R ¹⁰ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing group, and two or more of R ⁸ to R ¹⁰ may be bonded to each other to form a ring;
The filled circle (●) is the point of attachment to the nitrogen atom in formula (I).

［式（ＩＩＩ）中、
Ｒ¹²およびＲ¹⁵は、水素原子であり、黒丸（●）と結合する炭素原子に結合している、環を構成する炭素原子にそれぞれ、Ｒ¹²およびＲ¹⁵が結合していることを意味し、
Ｒ¹³は、炭素数３～８の２価の飽和炭化水素基であり、
Ｒ¹⁴は、ハロゲン原子、炭化水素基またはヘテロ原子含有基であり、
ｎは、０またはＲ¹³の炭素数の２倍以下の整数であり、ｎが２以上の整数の場合、複数のＲ¹⁴は互いに同一でも異なっていてもよく、
黒丸（●）は、式（Ｉ）中の窒素原子との結合点である。］

[In the formula (III),
R ¹² and R ¹⁵ are hydrogen atoms, and R ¹² and R ¹⁵ are bonded to carbon atoms constituting a ring bonded to the carbon atom bonded to the black circle (●),
R ¹³ is a divalent saturated hydrocarbon group having 3 to 8 carbon atoms;
R ¹⁴ is a halogen atom, a hydrocarbon group, or a heteroatom-containing group;
n is 0 or an integer equal to or less than twice the number of carbon atoms of R ¹³ , and when n is an integer equal to or greater than 2, a plurality of R ¹⁴ s may be the same or different from each other;
The filled circle (●) is the point of attachment to the nitrogen atom in formula (I).

［式（ＩＶ）中、
Ｍは周期表第３族～第１１族の遷移金属原子であり、
Ｃｐ¹およびＣｐ²はそれぞれ独立に、Ｍと共にサンドイッチ構造を形成することができるシクロペンタジエニル基または置換シクロペンタジエニル基であり、
ｊは、１～４の整数であり、
Ｑは、水素原子、ハロゲン原子、炭化水素基またはヘテロ原子含有基であり、ｊが２以上の場合、Ｑで示される複数の基は互いに同一でも異なっていてもよく、またＱで示される複数の基は互いに結合して環を形成してもよく、
Ｙは、炭素数１～３０の２価の炭化水素基、炭素数１～２０の２価のハロゲン化炭化水素基、２価のケイ素含有基、２価のゲルマニウム含有基、２価のスズ含有基、－Ｏ－、－ＣＯ－、－Ｓ－、－ＳＯ－、－ＳＯ₂－、－Ｇｅ－、－Ｓｎ－、－ＮＲ^a－、－Ｐ（Ｒ^a）－、－Ｐ（Ｏ）（Ｒ^a）－、－ＢＲ^a－または－ＡｌＲ^a－（Ｒ^aは、炭素数１～２０の炭化水素基、炭素数１～２０のハロゲン化炭化水素基、水素原子、ハロゲン原子、－ＮＲＨまたは－ＮＲ₂（Ｒは独立に、炭素数１～２０の炭化水素基））である。］

[In the formula (IV),
M is a transition metal atom of Groups 3 to 11 of the periodic table;
^Cp1 and ^Cp2 are each independently a cyclopentadienyl group or a substituted cyclopentadienyl group capable of forming a sandwich structure with M;
j is an integer from 1 to 4,
Q represents a hydrogen atom, a halogen atom, a hydrocarbon group or a heteroatom-containing group, and when j is 2 or more, the groups represented by Q may be the same or different, and the groups represented by Q may be bonded to each other to form a ring;
Y is a divalent hydrocarbon group having 1 to 30 carbon atoms, a divalent halogenated hydrocarbon group having 1 to 20 carbon atoms, a divalent silicon-containing group, a divalent germanium-containing group, a divalent tin-containing group, -O-, -CO-, -S-, -SO-, -SO ₂ -, -Ge-, -Sn-, -NR ^a -, -P(R ^a )-, -P(O)(R ^a )-, -BR ^{a - or -AlR a -} (wherein R ^a is a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, a hydrogen atom, a halogen atom, -NRH or -NR ₂ (wherein R is independently a hydrocarbon group having 1 to 20 carbon atoms)).

[2] The method for producing an ethylene-based polymer (E) according to [1], wherein the ethylene-based polymer (E) has an intrinsic viscosity [η] of 1.0 to 6.0 dl/g as measured in decalin at 135°C.
[3] The method for producing an ethylene-based polymer (E) according to [1] or [2], wherein the ethylene-based polymer (E) has a melt flow rate (MFR) of 0.01 to 5.0 g/10 min measured under conditions of a temperature of 190° C. and a load of 2.16 kg.
[4] The method for producing an ethylene polymer (E) according to any one of [1] to [3], wherein the ethylene polymer (E) has a density of 950 to 975 kg/ ^m3 .

The present invention provides a method for producing an ethylene-based polymer that can easily form a molded product with good appearance when producing an ethylene-based polymer by a slurry polymerization method using a single-site catalyst in continuous multi-stage polymerization.

Hereinafter, an embodiment of the present invention will be described.
In this specification, the term "polymer" is used to include homopolymers and copolymers. Thus, for example, the ethylene polymer (E) may be an ethylene homopolymer or an ethylene copolymer. Similarly, the term "polymerization" is used to include homopolymerization and copolymerization.
The details of the measuring methods for each physical property in the following description will be described in the Examples section.

<<Method for producing ethylene polymer (E)>>
The method for producing the ethylene polymer (E) according to the present invention (hereinafter also referred to as "the present method") comprises the steps of:
A method for continuously producing an ethylene polymer (E),
a step (1) of producing an ethylene polymer (e1) having an intrinsic viscosity [η] of 0.5 to 1.5 dl/g as measured in decalin at 135° C. by a slurry polymerization method in the presence of an olefin polymerization catalyst comprising a transition metal compound (A1) represented by formula (I) described later and a bridged metallocene compound (A2) represented by formula (IV) described later, in an amount of 20 to 80 mass % of the finally obtained ethylene polymer (E);
a step (2) of producing an ethylene polymer (e2) having an intrinsic viscosity [η] of 3.0 to 10.0 dl/g as measured in decalin at 135° C. by a slurry polymerization method in the presence of the ethylene polymer (e1) obtained in the step (1), in an amount of 20 to 80 mass% of the finally obtained ethylene polymer (E);
including.

In this method, the slurry containing the ethylene polymer (e1) and the olefin polymerization catalyst obtained in step (1), specifically the slurry containing polymer particles containing the ethylene polymer (e1) and the olefin polymerization catalyst obtained in step (1), is continuously supplied to step (2). This method is a polymerization method corresponding to continuous multi-stage polymerization in which polymerization for producing a further polymer component is continuously performed in the presence of at least one polymer component.

According to this method, it is possible to produce an ethylene-based polymer (E) that can easily form a molded article having a good appearance. The inventors speculate that the reason for this is as follows.

When ethylene polymers are produced by the so-called continuous multi-stage polymerization/slurry polymerization method using an olefin polymerization catalyst, unlike the batch method, polymer particles with various residence times exist in each polymerization vessel. Therefore, in the upstream polymerization vessel, there exist catalyst components that are transferred to the downstream polymerization vessel before sufficient polymer is synthesized around the olefin polymerization catalyst, i.e., components containing catalyst with insufficient polymerization history (hereinafter also referred to as "short-path components").

For example, in the case of a design in which the molecular weight of the polymer produced upstream is small and the molecular weight of the polymer produced downstream is large, the polymerization conditions downstream are designed to promote high molecular weight. Since the olefin polymerization catalyst in the short-path component has insufficient polymerization history, it is likely to exhibit excessive polymerization activity in the downstream polymerization vessel, and therefore large-sized polymer particles containing more high-molecular-weight components than expected are produced. Such large-sized polymer particles have low dispersibility in the molded product, causing poor appearance of the molded product.

In the present method, even if such short-path components are transferred to the downstream side, the production of large-sized polymer particles containing a larger amount of high molecular weight components than expected is suppressed, and it is believed that this makes it possible to easily obtain molded products with good appearance. This is believed to be because the olefin polymerization catalyst has the property that the polymerization activity does not become excessive even if the polymerization history on the upstream side is insufficient, or because it is possible to suppress the intrinsic viscosity [η] of the polymer synthesized on the downstream side from becoming excessively high.
It should be noted that the above explanation is merely speculation and does not limit the present invention in any way.

<Step (1)>
The ethylene polymer (e1) obtained in the step (1) has an intrinsic viscosity [η] of 0.5 to 1.5 dl/g, preferably 0.7 to 1.3 dl/g, measured in decalin at 135° C. For example, the [η] can be adjusted by changing the ratio of the amounts of hydrogen molecules, ethylene, and α-olefin supplied to a polymerization vessel or by changing the polymerization temperature.

In the ethylene polymer (e1), the content of ethylene-derived structural units is usually 80.0 mol% or more, preferably 85.0 mol% or more, more preferably 90.0 mol% or more, particularly preferably 95.0 mol% or more, and particularly preferably 98.0 mol% or more. In one embodiment, the amount of ethylene supplied in step (1) is preferably 2 to 20 kg/hr, more preferably 4 to 15 kg/hr.

The ethylene polymer (e1) may have, for example, a structural unit derived from an α-olefin having 3 to 20 carbon atoms. Examples of α-olefins having 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms, include propylene, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-tetradecene, 1-hexadecene, 1-heptadecene, 1-octadecene, and 1-eicosene.

In the ethylene polymer (e1), the content of structural units derived from an α-olefin having 3 to 20 carbon atoms is usually 20.0 mol% or less, preferably 15.0 mol% or less, more preferably 10.0 mol% or less, particularly preferably 5.0 mol% or less, and particularly preferably 2.0 mol% or less.
When the ethylene polymer (e1) has a structural unit derived from an α-olefin having 3 to 20 carbon atoms, it may have only one type of structural unit or two or more types of such structural units.

In step (1), a slurry containing an ethylene-based polymer (e1) is obtained. The slurry concentration, i.e., the concentration of the ethylene-based polymer (e1) (particles), is usually 50 to 600 g/L, preferably 100 to 500 g/L. The slurry concentration can be calculated, for example, by filtering the slurry using Kiriyama filter paper (1 μm mesh) while washing with hexane at a filtering temperature of room temperature (25° C.).

Step (1) may be carried out in multiple steps, so long as an ethylene polymer (e1) having an intrinsic viscosity [η] measured in decalin at 135°C in the range of 0.5 to 1.5 dl/g is obtained.

The polymerization temperature in the step (1) is usually from 25 to 100°C, preferably from 50 to 90°C, and more preferably from 70 to 85°C.
The reaction pressure in the step (1) is usually from normal pressure to 10 MPaG, preferably from normal pressure to 5 MPaG.

In this method, step (1) is carried out continuously. Specifically, in one embodiment of this method, step (1) is carried out by continuously supplying a monomer component containing ethylene, hydrogen molecules, an olefin polymerization catalyst and a polymerization solvent, and optionally a surfactant, to a polymerization tank, and the slurry containing the ethylene polymer (e1) obtained in step (1) is continuously withdrawn from the polymerization tank, for example, continuously withdrawn from the polymerization tank so that the liquid level in the polymerization tank is constant. The polymerization tank used in step (1) may be one or more, and in one embodiment, one is used.

In step (1), the obtained slurry is continuously extracted from the polymerization tank. The average residence time of the slurry in the polymerization tank is usually 0.5 to 8.0 hours, preferably 1.5 to 6.0 hours. When step (1) is carried out using multiple polymerization tanks, it is preferable that the average residence time of the slurry in each polymerization tank is within the above range.

The amount of hydrogen molecules supplied in step (1) is preferably 0.10 mol or less, more preferably 0.05 mol or less, per mol of the ethylene-containing monomer component. By using hydrogen molecules, the intrinsic viscosity [η] of the ethylene-based polymer obtained in each step can be adjusted.

Examples of polymerization solvents include hydrocarbon solvents, specifically, 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; and halogenated hydrocarbons such as ethylene chloride, chlorobenzene, and dichloromethane. One or more polymerization solvents may be used.

This method employs slurry polymerization, which is characterized in that the polymer (ethylene-based polymer) produced by polymerization exists in the form of fine particles dispersed in a medium such as the polymerization solvent.

The polymerization tank used in step (1) is usually one that has a supply means for continuously supplying the raw material components, such as monomer components including ethylene, hydrogen molecules, an olefin polymerization catalyst, and a polymerization solvent, and an extraction means for continuously extracting the contents of the polymerization tank from the polymerization tank so that the liquid level in the polymerization tank is constant.

In order to control the reaction conditions in step (2), it is preferable to remove unreacted ethylene and hydrogen molecules from the contents, such as the slurry containing the ethylene polymer (e1), continuously withdrawn from the polymerization tank. For example, a flash drum is used for the removal. The removal step can be carried out, for example, under reduced pressure conditions at a predetermined temperature, and the reduced pressure conditions are an internal pressure of usually 0.2 MPaG or less, preferably 0.1 MPaG or less, and a temperature of usually 20 to 80°C, preferably 30 to 75°C.

In step (1), the ethylene polymer (e1) is produced in an amount of 20 to 80% by mass, preferably 30 to 78% by mass, and more preferably 40 to 75% by mass, of the final ethylene polymer (E).

The mass ratio of the ethylene polymers (e1) and (e2) contained in the ethylene polymer (E) can be calculated, for example, by separating the peak curves originating from the ethylene polymers (e1) and (e2) from the molecular weight curve of the ethylene polymer (E) obtained by gel permeation chromatography (GPC) and calculating the mass ratio from each peak curve.

<Step (2)>
In step (2), the slurry containing the ethylene polymer (e1) and the olefin polymerization catalyst obtained in step (1) is continuously supplied to step (2), and an ethylene polymer (e2) having an intrinsic viscosity [η] of 3.0 to 10.0 dl/g measured in decalin at 135° C. is produced by a slurry polymerization method in the presence of the ethylene polymer (e1). Preferably, in step (2), the slurry continuously transferred from step (1), a monomer component containing ethylene, and hydrogen molecules and/or a polymerization solvent as necessary are continuously supplied to a polymerization tank of step (2) to carry out a polymerization reaction.

The ethylene polymer (e2) obtained in step (2) has an intrinsic viscosity [η] measured in decalin at 135°C of 3.0 to 10.0 dl/g, preferably 4.0 to 8.0 dl/g.

In the ethylene polymer (e2), the content of ethylene-derived structural units is usually 80.0 mol% or more, preferably 85.0 mol% or more, and more preferably 90.0 mol% or more. In one embodiment, the amount of ethylene supplied in step (2) is preferably 1 to 10 kg/hr, more preferably 2 to 8 kg/hr.

The ethylene polymer (e2) may have, for example, a structural unit derived from an α-olefin having 3 to 20 carbon atoms. Examples of α-olefins having 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms, include propylene, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-tetradecene, 1-hexadecene, 1-heptadecene, 1-octadecene, and 1-eicosene.

In the ethylene polymer (e2), the content of structural units derived from an α-olefin having 3 to 20 carbon atoms is usually 20.0 mol % or less, preferably 15.0 mol % or less, and more preferably 10.0 mol % or less.
When the ethylene polymer (e2) has a structural unit derived from an α-olefin having 3 to 20 carbon atoms, it may have only one type of structural unit or two or more types of such structural units.

In step (2), a slurry containing an ethylene polymer (E) containing ethylene polymers (e1) and (e2) is obtained. The slurry concentration, i.e., the concentration of the ethylene polymer (E) (particles), is usually 50 to 600 g/L, preferably 100 to 500 g/L.

Step (2) may be carried out in multiple steps, so long as an ethylene polymer (e2) having an intrinsic viscosity [η] measured in decalin at 135°C in the range of 3.0 to 10.0 dl/g is obtained.

The polymerization temperature in step (2) is usually 25 to 100°C, preferably 50 to 90°C, and more preferably 65 to 85°C. The reaction pressure is usually normal pressure to 10 MPaG, and preferably normal pressure to 5 MPaG.

In this method, step (2) is carried out continuously. Specifically, in one embodiment of this method, step (2) is carried out by continuously supplying the slurry containing the ethylene polymer (e1) and the olefin polymerization catalyst transferred from step (1), the monomer component containing ethylene, and optionally hydrogen molecules, the polymerization solvent, etc., to a polymerization tank, and the slurry containing the ethylene polymer (E) obtained in step (2) is continuously withdrawn from the polymerization tank, for example, continuously withdrawn from the polymerization tank so that the liquid level in the polymerization tank is constant. The polymerization tank used in step (2) may be one or more, and in one embodiment, it is one.

In step (2), the obtained slurry is continuously extracted from the polymerization tank. The average residence time of the slurry in the polymerization tank is usually 0.3 to 5.0 hours, preferably 0.9 to 3.7 hours. When step (2) is carried out using multiple polymerization tanks, it is preferable that the average residence time of the slurry in each polymerization tank is within the above range.

The amount of hydrogen molecules supplied in step (2) is preferably 0.01 moles or less, more preferably 0.005 moles or less, per mole of the ethylene-containing monomer component.

Examples of the polymerization solvent include the hydrocarbon solvents exemplified in step (1). The polymerization solvent in step (2) may be the same as or different from the polymerization solvent in step (1). One type of polymerization solvent may be used, or two or more types may be used.

The polymerization tank used in step (2) is usually a tank having a supply means for continuously supplying the slurry continuously extracted from the polymerization tank in step (1), the raw material monomer components including ethylene, and hydrogen molecules, polymerization solvent, etc., as required, and an extraction means for continuously extracting the contents of the polymerization tank from the polymerization tank so that the liquid level in the polymerization tank is constant.

In step (2), the ethylene-based polymer (e2) is produced in an amount of 20 to 80% by mass, preferably 22 to 70% by mass, and more preferably 25 to 60% by mass, of the finally obtained ethylene-based polymer (E). In one embodiment, the total of the ethylene-based polymer (e1) and the ethylene-based polymer (e2) is 100% by mass of the ethylene-based polymer (E).

In one embodiment, the molecular weight curve of the ethylene polymer (E) in the GPC method is preferably multimodal, and more preferably bimodal.

When the ethylene polymer (E) is produced in two stages, for example, 20 to 80 mass% of the total amount of the ethylene polymer (e1) having an [η] of 0.5 to 1.5 dl/g is produced in the first polymerization tank, and 20 to 80 mass% of the total amount of the ethylene polymer (e2) having an [η] of 3.0 to 10.0 dl/g is produced in the second polymerization tank.

<Post-processing step>
The ethylene polymer (E) obtained by this method may be subjected, if necessary, to known post-treatment steps such as a catalyst deactivation treatment step, a catalyst residue removal step, a drying step, etc.
For example, there may be mentioned a method of separating the polymer from the polymerization solvent, unreacted monomer components, etc. using a solvent separation device simultaneously with or as soon as possible after the content of the polymerization tank is discharged from the polymerization tank; a method of adding an inert gas such as nitrogen to the content to forcibly discharge the polymerization solvent, unreacted monomer components, etc. from the system; a method of controlling the pressure applied to the content to forcibly discharge the polymerization solvent, unreacted monomer components, etc. from the system; a method of adding a large amount of polymerization solvent to the content to dilute the unreacted monomer components to a concentration at which polymerization is considered to not substantially occur; a method of adding a substance such as methanol that inactivates the polymerization catalyst; and a method of cooling the content to a temperature at which polymerization is considered to not substantially occur.
These methods may be carried out alone or in combination.

<Ethylene-Based Polymer (E)>
In the ethylene polymer (E), the content of structural units derived from ethylene is usually 80.0 mol % or more, preferably 85.0 mol % or more, and more preferably 90.0 mol % or more.
In the ethylene polymer (E), the content of structural units derived from an α-olefin having 3 to 20 carbon atoms is usually 20.0 mol % or less, preferably 15.0 mol % or less, and more preferably 10.0 mol % or less.

The ethylene polymer (E) has an intrinsic viscosity [η] measured in decalin at 135°C of usually 1.0 to 6.0 dl/g, preferably 1.3 to 5.0 dl/g, and more preferably 1.5 to 4.0 dl/g.

The ethylene polymer (E) has a melt flow rate (MFR) measured under conditions of a temperature of 190° C. and a load of 2.16 kg of usually 0.01 to 5.0 g/10 min, preferably 0.1 to 4.0 g/10 min, more preferably 0.2 to 3.0 g/10 min.
The MFR in the above range is preferable in terms of flowability during molding. It is desirable to adjust the MFR to a preferred range depending on the application.

The ethylene polymer (E) has a density of usually 950 to 975 kg/m ³ , preferably 952 to 973 kg/m ³ , and more preferably 955 to 970 kg/m ³ .
A density in the above range is preferable in terms of rigidity. Generally, the higher the density, the higher the rigidity, so it is desirable to adjust the density to an appropriate value depending on the application.

The ethylene polymer (E) may contain additives and/or other components such as pigments, provided that the object of the present invention is not impaired. Examples of additives include weathering stabilizers, heat stabilizers, antistatic agents, slip prevention agents, antiblocking agents, antifogging agents, lubricants, dyes, nucleating agents, plasticizers, antioxidants, hydrochloric acid absorbers, antioxidants, and surfactants. Examples of pigments include carbon black, titanium oxide, titanium yellow, phthalocyanine compounds, isoindolinone compounds, quinacridone compounds, condensed azo compounds, ultramarine blue, and cobalt blue.

By using ethylene polymer (E), it is easy to obtain a molded article that has a good appearance and a good balance of rigidity and strength.

The ethylene polymer (E) obtained by this method may be pelletized. Examples of the pelletization method include the following methods (1) and (2).
(1) A method in which the ethylene polymer (E) and the other components added as required are blended using an extruder, kneader or the like, and then cut to a predetermined size.
(2) A method in which the ethylene polymer (E) and the other components added as desired are dissolved in an appropriate good solvent (e.g., a hydrocarbon solvent such as hexane, heptane, decane, cyclohexane, benzene, toluene, xylene, etc.), the solvent is then removed, and the mixture is blended using an extruder, kneader, etc., and cut to a predetermined size.

The ethylene polymer (E) or a composition containing the polymer (E) can be molded into a blown product, an inflation product, a cast product, an extrusion laminate product, an extrusion product such as a pipe or a modified shape, a foamed product, an injection molded product, a press molded product, or the like, and can also be used for fibers, monofilaments, nonwoven fabrics, or the like. These molded products include molded products (e.g., laminates) having a portion formed from the ethylene polymer (E) or a composition containing the polymer (E) and a portion formed from another resin. The ethylene polymer (E) may also be crosslinked during the molding process.

[Olefin polymerization catalyst]
The olefin polymerization catalyst used in this process will now be described.
The olefin polymerization catalyst comprises a transition metal compound (A1) represented by formula (I) and a bridged metallocene compound (A2) represented by formula (IV). The olefin polymerization catalyst preferably further comprises a cocatalyst (B). From the viewpoint of performing slurry polymerization, the olefin polymerization catalyst preferably further comprises a carrier (C) supporting the transition metal compound (A1) and/or the bridged metallocene compound (A2).

<Transition metal compound (A1) represented by formula (I)>
The transition metal compound (A1) is represented by formula (I).
The transition metal compound (A1) contained in the olefin polymerization catalyst may be one type or two or more types.

The meanings of each symbol in formula (I) are as follows.
In formula (I), N...M generally indicate that they are coordinated, but in the present invention they may or may not be coordinated.

M is a transition metal atom of Group 4 of the periodic table, preferably titanium, zirconium or hafnium, more preferably zirconium.

m is an integer from 1 to 4, preferably 2.

R ¹ to R ⁵ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing group. Two or more of R ¹ to R ⁵ , preferably adjacent groups, may be linked to each other to form a ring such as an aliphatic ring, an aromatic ring, or a hydrocarbon ring containing a heteroatom such as a nitrogen atom, and these rings may further have a substituent. When m is 2 or more, at least two groups among the groups represented by R ¹ to R ⁵ may be linked. When m is 2 or more, R ¹ 's, R ² 's, R ³ 's, R ⁴ 's, and R ⁵ 's may be the same or different from each other.

R ⁶ is a group represented by the formula C _n' H _2n'+1 (n' is an integer of 1 to 8), formula (II) or formula (III), which will be described later.

j is a number that satisfies the valence of M, specifically an integer from 0 to 5, preferably from 1 to 4, and more preferably from 1 to 3.

X is a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing group, and in one embodiment is a halogen atom. When j is 2 or more, the groups represented by X may be the same or different, and the groups represented by X may be bonded to each other to form a ring.

Specific examples of the atoms and groups in R ¹ to R ⁵ and X will be explained below.

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

Examples of the hydrocarbon group include:
linear or branched alkyl groups having 1 to 30, preferably 1 to 20, carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a neopentyl group, or an n-hexyl group;
linear or branched alkenyl groups having 2 to 30, preferably 2 to 20, carbon atoms, such as a vinyl group, an allyl group, or an isopropenyl group;
linear or branched alkynyl groups having 2 to 30, preferably 2 to 20, carbon atoms, such as an ethynyl group or a propargyl group;
cyclic saturated hydrocarbon groups having 3 to 30, preferably 3 to 20, carbon atoms, such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, or an adamantyl group;
cyclic unsaturated hydrocarbon groups having 5 to 30 carbon atoms, such as a cyclopentadienyl group, an indenyl group, or a fluorenyl group;
an aryl group or a substituted aryl group having 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms, such as a phenyl group, a naphthyl group, a biphenyl group, a terphenyl group, a phenanthryl group, an anthracenyl group, a tolyl group, an iso-propylphenyl group, a tert-butylphenyl group, a dimethylphenyl group, or a di-tert-butylphenyl group;
Aryl-substituted alkyl groups such as a benzyl group, a cumyl group, a 1,1-diphenylethyl group, a 2,2-diphenylethyl group, and a triphenylmethyl group;
Examples include:

Among these, particularly preferred are linear or branched alkyl groups having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, neopentyl, and n-hexyl; aryl-substituted alkyl groups in which a substituent such as an aryl group having 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms, is bonded to these alkyl groups; cyclic saturated hydrocarbon groups having 3 to 30 carbon atoms, preferably 3 to 20 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and adamantyl; aryl groups having 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms, such as phenyl, naphthyl, biphenyl, terphenyl, phenanthryl, and anthracenyl; and substituted aryl groups in which these aryl groups are substituted with 1 to 5 substituents such as an alkyl group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, or an aryl group having 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms.

Examples of the heteroatom-containing group in R ¹ to R ⁵ include a heterocycle-containing group, an oxygen-containing group, a nitrogen-containing group, a sulfur-containing group, a silicon-containing group, a germanium-containing group, a tin-containing group, a boron-containing group, a phosphorus-containing group, and a halogen-containing group;
Examples of the heteroatom-containing group for X include a heterocycle-containing group, an oxygen-containing group, a nitrogen-containing group, a sulfur-containing group, a silicon-containing group, a germanium-containing group, a tin-containing group, a boron-containing group, a phosphorus-containing group, a halogen-containing group, and an aluminum-containing group.

Examples of the heterocycle-containing group include nitrogen-containing groups such as pyrrole, pyridine, pyrimidine, quinoline, and triazine, oxygen-containing groups such as furan and pyran, and sulfur-containing groups such as thiophene, as well as groups in which these groups are further substituted with a substituent such as an alkyl group or alkoxy group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.

Examples of the oxygen-containing group include alkoxy groups, aryloxy groups, ester groups, ether groups, acyl groups, carboxy groups, carbonate groups, hydroxy groups, peroxy groups, carboxylic anhydride groups, and groups in which at least a portion of the hydrocarbon group is substituted with these groups. Examples of the group in which at least a portion of the hydrocarbon group is substituted with these groups include oxygen-containing aryl groups in which an aryl group having 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms, is substituted with 1 to 5 substituents such as an alkoxy group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, or an aryloxy group having 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms.

Examples of the nitrogen-containing group include an amino group, an imino group, an amide group, an imide group, a hydrazino group, a hydrazono group, a nitro group, a nitroso group, a cyano group, an isocyano group, a cyanate ester group, an amidino group, a diazo group, an ammonium base, and a group in which at least a portion of the hydrocarbon group is substituted with one of these groups.

Examples of the sulfur-containing group include a mercapto group, a thioester group, a dithioester group, an alkylthio group, an arylthio group, a thioacyl group, a thioether group, a thiocyanate ester group, an isocyanate ester group, a sulfone ester group, a sulfonamide group, a thiocarboxy group, a dithiocarboxy group, a sulfo group, a sulfonyl group, a sulfinyl group, a sulfenyl group, and a group in which at least a portion of the hydrocarbon group is substituted with one of these groups.

Examples of the silicon-containing group include silyl groups, siloxy groups, hydrocarbon-group-substituted silyl groups, hydrocarbon-group-substituted siloxy groups, and groups in which at least a portion of the hydrocarbon group is substituted with these groups. Specific examples of the hydrocarbon-group-substituted silyl groups include methylsilyl groups, dimethylsilyl groups, trimethylsilyl groups, ethylsilyl groups, diethylsilyl groups, triethylsilyl groups, diphenylmethylsilyl groups, triphenylsilyl groups, dimethylphenylsilyl groups, and dimethyl-tert-butylsilyl groups. Specific examples of the hydrocarbon-group-substituted siloxy groups include trimethylsiloxy groups.

The germanium-containing group and the tin-containing group include, for example, groups in which the silicon atom of the silicon-containing group is replaced with a germanium atom and a tin atom.

Examples of the boron-containing group in R ¹ to R ⁵ include a boranediyl group, a boranetriyl group, a diboranyl group, and groups in which at least a portion of the hydrocarbon group is substituted with these groups.

The boron-containing group for X is, for example, BR ₄ (R represents a hydrogen atom, an alkyl group, an aryl group which may have a substituent, a halogen atom, or the like).

Examples of the phosphorus-containing group in R ¹ to R ⁵ include a phosphido group, a phosphoryl group, a thiophosphoryl group, a phosphato group, and groups in which at least a portion of the hydrocarbon group is substituted with these groups.

Examples of the phosphorus-containing group in X include tri(cyclo)alkylphosphine groups such as trimethylphosphine group, tributylphosphine group, and tricyclohexylphosphine group; triarylphosphine groups such as triphenylphosphine group and tritolylphosphine group; phosphite groups (phosphido groups) such as methylphosphine group, ethylphosphine group, and phenylphosphine group; phosphonic acid groups; and phosphinic acid groups.

Examples of the halogen-containing group in R ¹ to R ⁵ include groups in which at least one hydrogen atom of the hydrocarbon group is substituted with a halogen atom, specifically, halogenated hydrocarbon groups having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, such as trifluoromethyl, pentafluorophenyl and chlorophenyl groups, and preferably halogenated aryl groups in which 1 to 5 halogen atoms are substituted on an aryl group having 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms.

Examples of the halogen-containing group for X include fluorine-containing groups such as PF ₆ and BF ₄ , chlorine-containing groups such as ClO ₄ and SbCl ₆ , and iodine-containing groups such as IO ₄ .

Examples of the aluminum-containing group for X include AlR ₄ (R represents a hydrogen atom, an alkyl group, an aryl group which may have a substituent, a halogen atom, etc.).

R ¹ to R ⁵ are preferably a hydrogen atom, a halogen atom, a hydrocarbon group, a silicon-containing group, or a halogen-containing group, and more preferably a hydrogen atom or a hydrocarbon group. Among the above-mentioned hydrocarbon groups, the above-mentioned alkyl group, cyclic saturated hydrocarbon group, aryl group, and aryl-substituted alkyl group are preferred.

R ⁶ is a group represented by the formula C _n′ H _2n′+1 (n′ is an integer of 1 to 8), formula (II) or formula (III).
When R ⁶ is one of these groups, an ethylene polymer having a relatively low molecular weight, for example, Mw of 500 to 10,000, can be easily produced, and as described above, even if the short-path component is transferred to the downstream side, the polymerization activity does not become excessively high, or an olefin polymerization catalyst capable of suppressing the intrinsic viscosity [η] of the polymer synthesized on the downstream side from becoming excessively high tends to be easily obtained.

Specific examples of the group represented by the formula C _n' H _2n'+1 include acyclic hydrocarbon groups such as a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an iso-propyl group, an iso-butyl group, a tert-butyl group, a neopentyl group, an n-hexyl group, an n-heptyl group, and an isoheptyl group. An isoheptyl group is preferred.

In formula (II), R ⁷ and R ¹¹ are hydrogen atoms, and R ⁸ to R ¹⁰ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing group.

Examples of the heteroatom-containing group include a heterocycle-containing group, an oxygen-containing group, a nitrogen-containing group, a sulfur-containing group, a silicon-containing group, a germanium-containing group, a tin-containing group, a boron-containing group, a phosphorus-containing group, and a halogen-containing group.

Examples of the halogen atoms, hydrocarbon groups and heteroatom-containing groups in R ⁸ to R ¹⁰ include the same groups as those exemplified for R ¹ to R ⁵ above, and preferred groups are also the same.
R ⁸ to R ¹⁰ are preferably a hydrogen atom, a halogen atom, a hydrocarbon group, a silicon-containing group or a halogen-containing group, and more preferably a hydrogen atom or a hydrocarbon group.

Two or more of R ⁸ to R ¹⁰ may be bonded to each other to form a ring, and the ring is preferably an aliphatic ring, an aromatic ring, or a ring containing a heteroatom such as a nitrogen atom, and these rings may further have a substituent.

In formula (II), the black circle (●) represents the point of attachment to the nitrogen atom in formula (I).

In formula (III), R ¹² and R ¹⁵ are hydrogen atoms, R ¹³ is a divalent saturated hydrocarbon group having 3 to 8 carbon atoms, R ¹⁴ is a halogen atom, a hydrocarbon group or a heteroatom-containing group, and the black circle (●) is the point of attachment to the nitrogen atom in formula (I).
In addition, R ¹² and R ¹⁵ mean that R ¹² and R ¹⁵ are bonded to the carbon atoms constituting the ring that are bonded to the carbon atom bonded to the black circle (●), respectively. For example, when R ¹³ is tetramethylene and the carbon atom constituting the ring bonded to the black circle (●) is considered to be the 1st position, R ¹² and R ¹⁵ mean that they are bonded to the carbon atoms constituting the ring at the 2nd and 6th positions, respectively.

Examples of the heteroatom-containing group include a heterocycle-containing group, an oxygen-containing group, a nitrogen-containing group, a sulfur-containing group, a silicon-containing group, a germanium-containing group, a tin-containing group, a boron-containing group, a phosphorus-containing group, and a halogen-containing group.

Examples of the halogen atom, hydrocarbon group and heteroatom-containing group in R ¹⁴ include the same groups as those exemplified for R ¹ to R ⁵ above, and the preferred groups are also the same.
R ¹⁴ is preferably a halogen atom, a hydrocarbon group, a silicon-containing group or a halogen-containing group, more preferably a hydrocarbon group.

Examples of the divalent saturated hydrocarbon group having 3 to 8 carbon atoms include trimethylene, tetramethylene, pentamethylene, and hexamethylene, and preferably a divalent saturated hydrocarbon group having 4 to 6 carbon atoms. For example, when R ¹³ is tetramethylene, the ring represented by formula (III) is a 6-membered ring.

n is 0 or an integer not exceeding twice the number of carbon atoms of R ¹³ , and when n is an integer of 2 or more, multiple R ¹⁴ may be the same or different. n is preferably 0.

The method for producing the transition metal compound (A1) is not particularly limited, and it can be produced, for example, by the method described in JP-A-11-315109 or EP 0874005 A1.

<Bridged metallocene compound (A2) represented by formula (IV)>
The bridged metallocene compound (A2) is represented by the formula (IV).
It is believed that the use of such a compound (A2) makes it possible to obtain an ethylene-based polymer having high rigidity and impact strength.

［式（ＩＶ）中、
Ｍは周期表第３族～第１１族の遷移金属原子であり、
Ｃｐ¹およびＣｐ²はそれぞれ独立に、Ｍと共にサンドイッチ構造を形成することができるシクロペンタジエニル基または置換シクロペンタジエニル基であり、
ｊは、１～４の整数であり、
Ｑは、水素原子、ハロゲン原子、炭化水素基またはヘテロ原子含有基であり、ｊが２以上の場合、Ｑで示される複数の基は互いに同一でも異なっていてもよく、またＱで示される複数の基は互いに結合して環を形成してもよく、
Ｙは、炭素数１～３０の２価の炭化水素基、炭素数１～２０の２価のハロゲン化炭化水素基、２価のケイ素含有基、２価のゲルマニウム含有基、２価のスズ含有基、－Ｏ－、－ＣＯ－、－Ｓ－、－ＳＯ－、－ＳＯ₂－、－Ｇｅ－、－Ｓｎ－、－ＮＲ^a－、－Ｐ（Ｒ^a）－、－Ｐ（Ｏ）（Ｒ^a）－、－ＢＲ^a－または－ＡｌＲ^a－（Ｒ^aは、炭素数１～２０の炭化水素基、炭素数１～２０のハロゲン化炭化水素基、水素原子、ハロゲン原子、－ＮＲＨまたは－ＮＲ₂（Ｒは独立に、炭素数１～２０の炭化水素基））である。］

[In the formula (IV),
M is a transition metal atom of Groups 3 to 11 of the periodic table;
^Cp1 and ^Cp2 are each independently a cyclopentadienyl group or a substituted cyclopentadienyl group capable of forming a sandwich structure with M;
j is an integer from 1 to 4,
Q represents a hydrogen atom, a halogen atom, a hydrocarbon group or a heteroatom-containing group, and when j is 2 or more, the groups represented by Q may be the same or different, and the groups represented by Q may be bonded to each other to form a ring;
Y is a divalent hydrocarbon group having 1 to 30 carbon atoms, a divalent halogenated hydrocarbon group having 1 to 20 carbon atoms, a divalent silicon-containing group, a divalent germanium-containing group, a divalent tin-containing group, -O-, -CO-, -S-, -SO-, -SO ₂ -, -Ge-, -Sn-, -NR ^a -, -P(R ^a )-, -P(O)(R ^a )-, -BR ^{a - or -AlR a -} (wherein R ^a is a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, a hydrogen atom, a halogen atom, -NRH or -NR ₂ (wherein R is independently a hydrocarbon group having 1 to 20 carbon atoms)).

In formula (IV), M can be, for example, scandium, yttrium, lanthanum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, manganese, iron, cobalt, nickel, or palladium, and is preferably a transition metal atom of Groups 4 to 10 of the periodic table, more preferably Groups 4 to 5 of the periodic table, and even more preferably Group 4 of the periodic table, and is particularly preferably titanium, zirconium, or hafnium, and most preferably zirconium or hafnium.

The substituted cyclopentadienyl in Cp ¹ and Cp ² is a group in which at least one hydrogen atom of cyclopentadienyl is substituted with a substituent.
When the substituted cyclopentadienyl has adjacent substituents, the adjacent substituents may be bonded to each other to form a ring.

Examples of the substituent in the substituted cyclopentadienyl include a hydrocarbon group (hereinafter also referred to as "group (f1)") or a silicon-containing hydrocarbon group (hereinafter also referred to as "group (f2)"). Other examples of the substituent in the substituted cyclopentadienyl include heteroatom-containing groups (excluding group (f2)) such as halogen-containing groups, oxygen-containing groups, nitrogen-containing groups, boron-containing groups, sulfur-containing groups, phosphorus-containing groups, silicon-containing groups, germanium-containing groups, and tin-containing groups, in particular heteroatom-containing hydrocarbon groups (excluding group (f2)).

The group (f1) is preferably a hydrocarbon group having 1 to 20 carbon atoms, such as a linear or branched hydrocarbon group (e.g., alkyl, alkenyl, alkynyl), a cyclic saturated hydrocarbon group (e.g., cycloalkyl), or a cyclic unsaturated hydrocarbon group (e.g., aryl). The group (f1) also includes groups in which any two hydrogen atoms bonded to adjacent carbon atoms among the above-mentioned groups are simultaneously substituted to form an alicyclic ring or aromatic ring. The alicyclic ring and aromatic ring may have a substituent.

Specific examples of the group (f1) include linear aliphatic hydrocarbon groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decanyl, and allyl; isopropyl, isobutyl, sec-butyl, tert-butyl, amyl, 3-methylpentyl, neopentyl, 1,1-diethylpropyl, 1,1-dimethylbutyl, 1-methyl-1-propylbutyl, 1,1-propylbutyl, and 1,1-dimethyl-2-methyl-2-phenylpropane. branched aliphatic hydrocarbon groups such as 1-methylpropyl, 1-methyl-1-isopropyl-2-methylpropyl; cyclic saturated hydrocarbon groups such as cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, norbornyl, and adamantyl; cyclic unsaturated hydrocarbon groups and their nuclear alkyl-substituted derivatives such as phenyl, naphthyl, biphenyl, phenanthryl, and anthracenyl; and groups in which at least one hydrogen atom of a saturated hydrocarbon group is substituted with an aryl group, such as benzyl and cumyl.

Among the groups (f1), preferred examples include linear or branched aliphatic hydrocarbon groups having 1 to 20 carbon atoms, specifically, methyl, ethyl, n-propyl, n-butyl, n-hexyl, isopropyl, isobutyl, sec-butyl, tert-butyl, and neopentyl.

The group (f2) is preferably a silicon-containing hydrocarbon group having 1 to 20 carbon atoms, such as a group in which a silicon atom is directly covalently bonded to a carbon atom of a cyclopentadienyl ring. Specific examples include alkylsilyl (e.g., trimethylsilyl) and arylsilyl (e.g., triphenylsilyl).

Specific examples of heteroatom-containing hydrocarbon groups (excluding group (f2)) include methoxy, ethoxy, phenoxy, N-methylamino, trifluoromethyl, tribromomethyl, pentafluoroethyl, pentafluorophenyl, etc.

Q is a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing group, specifically a hydrogen atom, a halogen atom, a hydrocarbon group, an oxygen-containing group, a sulfur-containing group, a nitrogen-containing group, a boron-containing group, an aluminum-containing group, a phosphorus-containing group, a halogen-containing group, a heterocycle-containing group, a silicon-containing group, a germanium-containing group, or a tin-containing group, and more specifically, the same groups as those exemplified for X in formula (I) above can be mentioned.

In formula (IV), j is preferably an integer of 2 to 4, more preferably 2 or 3. When j is an integer of 2 or more, the multiple Qs may be the same or different, and the multiple groups represented by Q may be bonded to each other to form a ring.

Examples of the divalent hydrocarbon group, divalent halogenated hydrocarbon group, divalent silicon-containing group, divalent germanium-containing group, and divalent tin-containing group for Y include groups in which one hydrogen atom has been removed from the same groups as those exemplified for R ¹ to R ⁵ above.
Examples of the hydrocarbon group and halogenated hydrocarbon group for R ^a and R include the same groups as those exemplified for R ¹ to R ⁵ above.

Among these bridged metallocene compounds, the bridged metallocene compound represented by the following formula (VIII) is preferred.

［式（ＶＩＩＩ）中、Ｒ¹⁵～Ｒ¹⁸およびＲ¹⁹～Ｒ²⁶は、水素原子、炭化水素基、ハロゲン含有基、酸素含有基、窒素含有基、ホウ素含有基、イオウ含有基、リン含有基、ケイ素含有基、ゲルマニウム含有基またはスズ含有基を示し、それぞれ同一でも異なっていてもよく、また、隣接した置換基は互いに結合して環を形成してもよく、Ｑ¹は、炭素数１～２０の炭化水素基、炭素数１～２０のハロゲン含有基、ケイ素含有基、ゲルマニウム含有基またはスズ含有基を示し、Ｍは、チタン原子、ジルコニウム原子またはハフニウム原子を示し、Ｘはそれぞれ独立に、水素原子、ハロゲン原子、炭化水素基、ハロゲン含有基、ケイ素含有基、酸素含有基、イオウ含有基、窒素含有基またはリン含有基を示す。］

[In formula (VIII), R ¹⁵ to R ¹⁸ and R ¹⁹ to R ²⁶ each represent a hydrogen atom, a hydrocarbon group, a halogen-containing group, an oxygen-containing group, a nitrogen-containing group, a boron-containing group, a sulfur-containing group, a phosphorus-containing group, a silicon-containing group, a germanium-containing group, or a tin-containing group, and may be the same or different. Adjacent substituents may be bonded to each other to form a ring; Q ¹ represents a hydrocarbon group having 1 to 20 carbon atoms, a halogen-containing group having 1 to 20 carbon atoms, a silicon-containing group, a germanium-containing group, or a tin-containing group; M represents a titanium atom, a zirconium atom, or a hafnium atom; and each X independently represents 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, or a phosphorus-containing group.]

In formula (VIII), M is preferably zirconium.

R ¹⁵ to R ¹⁸ and R ¹⁹ to R ²⁶ each independently include the same groups as those exemplified for R ¹ to R ⁵ above.

In addition, at least one pair of adjacent groups among R ¹⁵ to R ¹⁸ may be bonded to each other to form a ring, for example, an indenyl group, a substituted indenyl group, a fluorenyl group or a substituted fluorenyl group, and at least one pair of adjacent groups among R ¹⁹ to R ²⁶ may be bonded to each other to form a ring, for example, a benzofluorenyl group, a dibenzofluorenyl group, an octahydrodibenzofluorenyl group or an octamethyloctahydrodibenzofluorenyl group, and it is particularly preferable that they form an octamethyloctahydrodibenzofluorenyl group.

^Q1 is a divalent group, and is a divalent hydrocarbon group having 1 to 20 carbon atoms, such as an alkylene group, a substituted alkylene group, or an alkylidene group, a divalent halogen-containing group having 1 to 20 carbon atoms, a divalent silicon-containing group, a divalent germanium-containing group, or a divalent tin-containing group.

Specific examples of the divalent hydrocarbon group having 1 to 20 carbon atoms include alkylene groups such as methylene, ethylene, propylene, and butylene, isopropylidene, diethylmethylene, dipropylmethylene, diisopropylmethylene, dibutylmethylene, methylethylmethylene, methylbutylmethylene, methyl-tert-butylmethylene, dihexylmethylene, dicyclohexylmethylene, methylcyclohexylmethylene, methylphenylmethylene, diphenylmethylene, di(p-tolyl)methylene, ditolylmethylene, and methylene. These include substituted alkylene groups such as ethylnaphthylmethylene, dinaphthylmethylene, 1-methylethylene, 1,2-dimethylethylene, and 1-ethyl-2-methylethylene; cycloalkylene groups such as cyclopropylidene, cyclobutylidene, cyclopentylidene, cyclohexylidene, cycloheptylidene, bicyclo[3.3.1]nonylidene, norbornylidene, adamantylidene, tetrahydronaphthylidene, and dihydroindanylidene; and alkylidene groups such as ethylidene, propylidene, and butylidene.

Examples of divalent silicon-containing groups include silylene, methylsilylene, dimethylsilylene, diisopropylsilylene, dibutylsilylene, methylbutylsilylene, methyl-tert-butylsilylene, dicyclohexylsilylene, methylcyclohexylsilylene, methylphenylsilylene, diphenylsilylene, ditolylsilylene, methylnaphthylsilylene, dinaphthylsilylene, cyclodimethylenesilylene, cyclotrimethylenesilylene, cyclotetramethylenesilylene, cyclopentamethylenesilylene, cyclohexamethylenesilylene, and cycloheptamethylenesilylene. Examples of divalent germanium-containing groups and divalent tin-containing groups include the divalent silicon-containing groups in which silicon has been converted to germanium or tin.

Divalent halogen-containing groups having 1 to 20 carbon atoms include groups in which one or more hydrogen atoms in the divalent hydrocarbon groups or divalent silicon-containing groups are substituted with halogen atoms, such as bis(trifluoromethyl)methylene, 4,4,4-trifluorobutylmethylmethylene, bis(trifluoromethyl)silylene, and 4,4,4-trifluorobutylmethylsilylene.

^Q1 may also have a structure represented by either formula (IX) or formula (X) below.

In formula (IX) and formula (X), Y independently represents a carbon atom, a silicon atom, a germanium atom, or a tin atom. R ²⁷ and R ²⁸ are selected from a hydrogen atom, a hydrocarbon group, a silicon-containing group, a germanium-containing group, a tin-containing group, and a halogen-containing group, and may be the same or different. A represents a divalent hydrocarbon group having 2 to 20 carbon atoms which may contain an unsaturated bond, and A may contain two or more ring structures including the ring formed together with Y.
The filled circles (●) represent the points of attachment to the (substituted) cyclopentadienyl group and the (substituted) fluorenyl group.

In the formulas (IX) and (X), Y is preferably a carbon atom or a silicon atom, and is particularly preferably a carbon atom.

Examples of the hydrocarbon group, silicon-containing group, germanium-containing group, tin-containing group and halogen-containing group for R ²⁷ and R ²⁸ in formula (IX) include the same groups as those exemplified for R ¹ to R ⁵ above.
Among these groups, a group selected from a methyl group, a chloromethyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a tert-butyl group, a n-pentyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a phenyl group, a m-tolyl group, and a p-tolyl group is preferred, and a group selected from a methyl group, a chloromethyl group, a n-butyl group, a n-pentyl group, a phenyl group, a m-tolyl group, and a p-tolyl group is particularly preferred.

In formula (X), A is a divalent hydrocarbon group having 2 to 20 carbon atoms which may contain an unsaturated bond, and Y is bonded to A to form a 1-silacyclopentylidene group or the like.
In this specification, the 1-silacyclopentylidene group has the following formula (XI).

（式（ＸＩ）において、黒丸（●）は、式（ＩＸ）と同義である。）

(In formula (XI), the black circle (●) has the same meaning as formula (IX).)

Preferred groups for ^Q1 in formula (VIII) are groups selected from alkylene groups, substituted alkylene groups, alkylidene groups, halogen-containing alkylene groups, halogen-containing substituted alkylene groups, halogen-containing alkylidene groups, silicon-containing groups, and halogen-containing silicon-containing groups having 1 to 20 carbon atoms, and particularly preferred groups are alkylene groups, substituted alkylene groups, alkylidene groups, and silicon-containing groups having 1 to 20 carbon atoms.

X in the formula (VIII) is each independently a group selected from a hydrogen atom, a halogen atom, a hydrocarbon group, a halogen-containing group (e.g., a halogen-containing hydrocarbon group), a silicon-containing group, an oxygen-containing group, a sulfur-containing group, a nitrogen-containing group, and a phosphorus-containing group, and is preferably a halogen atom or a hydrocarbon group. Examples of the halogen atom, hydrocarbon group, halogen-containing group (e.g., a halogen-containing hydrocarbon group), a silicon-containing group, an oxygen-containing group, a sulfur-containing group, a nitrogen-containing group, and a phosphorus-containing group include the same groups as those exemplified for R ¹ to R ⁵ above.

In the formula (VIII), as preferred groups, R ¹⁵ to R ¹⁸ are selected as hydrogen atoms, R ¹⁹ to R ²⁶ are selected as hydrogen atoms or hydrocarbon groups, and at least two adjacent groups among R ¹⁹ to R ²⁶ are hydrocarbon groups, and at least one pair of the adjacent hydrocarbon groups are bonded to each other to form a ring, such as an octahydrodibenzofluorenyl group or an octamethyloctahydrodibenzofluorenyl group, are also selected as preferred groups. Regarding Q ¹ , a group represented by formula (IX) or formula (X) is selected, Y is a carbon atom, and R ²⁷ and R ²⁸ are selected as preferred groups. When a bridged metallocene compound represented by formula (VIII) having these groups is used, it is considered that an ethylene-based polymer produced from the transition metal compound (A1) and an ethylene-based polymer produced from the bridged metallocene compound (A2) have different molecular weights, and an ethylene-based polymer that can easily form a molded product with good appearance can be easily produced compared to a polymer obtained by using one of these components.

Specific examples of such bridged metallocene compounds represented by formula (VIII) are shown below, but are not limited to these.

Isopropylidene (cyclopentadienyl) (fluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl) (2,7-di-tert-butylfluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl) (3,6-di-tert-butylfluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl) (octamethyloctahydridodibenzfluorenyl) zirconium dichloride, dibutylmethylene (cyclopentadi dibutylmethylene(cyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride, dibutylmethylene(cyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, dibutylmethylene(cyclopentadienyl)(octamethyloctahydridodibenzfluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(fluorenyl)zirconium dichloride diphenylmethylene(cyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(octamethyloctahydridodibenzfluorenyl)zirconium dichloride, di(p-tolyl)methylene(cyclopentadienyl)(octamethyloctahydrodibenzofluorenyl)zirconium dichloride cyclohexylidene(cyclopentadienyl)(fluorenyl)zirconium dichloride, cyclohexylidene(cyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride, cyclohexylidene(cyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, cyclohexylidene(cyclopentadienyl)(octamethyloctahydridodibenzfluorenyl)zirconium dichloride phenylmethylmethylene(cyclopentadienyl)(fluorenyl)zirconium dichloride, phenylmethylmethylene(cyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride, phenylmethylmethylene(cyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, phenylmethylmethylene(cyclopentadienyl)(octamethyloctahydridodibenzfluorenyl)zirconium dichloride, di Methylsilyl(cyclopentadienyl)(fluorenyl)zirconium dichloride, dimethylsilyl(cyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride, dimethylsilyl(cyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, dimethylsilyl(cyclopentadienyl)(octamethyloctahydridodibenzfluorenyl)zirconium dichloride, isopropylidene(3-tert-butylcyclo pentadienyl) (fluorenyl) zirconium dichloride, isopropylidene (3-tert-butylcyclopentadienyl) (2,7-di-tert-butylfluorenyl) zirconium dichloride, isopropylidene (3-tert-butylcyclopentadienyl) (3,6-di-tert-butylfluorenyl) zirconium dichloride, isopropylidene (3-tert-butylcyclopentadienyl) (octamethyloctahydridodibenzfluorenyl) zirconium dichloride diphenylmethylene(3-tert-butylcyclopentadienyl)(fluorenyl)zirconium dichloride, diphenylmethylene(3-tert-butylcyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride, diphenylmethylene(3-tert-butylcyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, diphenylmethylene(3-tert-butylcyclopentadienyl)(octamethylol) 2,7-di-tert-butylfluorenyl)zirconium dichloride, cyclohexylidene(3-tert-butylcyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride, cyclohexylidene(3-tert-butylcyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, cyclohexylidene(3 -tert-butylcyclopentadienyl) (octamethyloctahydridodibenzfluorenyl) zirconium dichloride, phenylmethylmethylene (3-tert-butylcyclopentadienyl) (fluorenyl) zirconium dichloride, phenylmethylmethylene (3-tert-butylcyclopentadienyl) (2,7-di-tert-butylfluorenyl) zirconium dichloride, phenylmethylmethylene (3-tert-butylcyclopentadienyl) (3,6-di-tert- butylfluorenyl)zirconium dichloride, phenylmethylmethylene(3-tert-butylcyclopentadienyl)(octamethyloctahydridodibenzfluorenyl)zirconium dichloride, isopropylidene(3-tert-butyl-5-methylcyclopentadienyl)(fluorenyl)zirconium dichloride, isopropylidene(3-tert-butyl-5-methylcyclopentadienyl)(2,7-di-tert-butyl ... propylidene(3-tert-butyl-5-methylcyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, isopropylidene(3-tert-butyl-5-methylcyclopentadienyl)(octamethyloctahydridodibenzfluorenyl)zirconium dichloride, diphenylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(fluorenyl)zirconium dichloride, diphenylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(fluorenyl)zirconium dichloride diphenylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, diphenylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(octamethyloctahydridodibenzfluorenyl)zirconium dichloride, cyclohexylidene(3-tert-butyl-5-methylcyclopentadienyl)(octamethyloctahydridodibenzfluorenyl)zirconium dichloride cyclohexylidene(3-tert-butyl-5-methylcyclopentadienyl)(fluorenyl)zirconium dichloride, cyclohexylidene(3-tert-butyl-5-methylcyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride, cyclohexylidene(3-tert-butyl-5-methylcyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, cyclohexylidene(3-tert-butyl-5-methylcyclopentadienyl)(octamethyloctahydride dibenzyl phenylmethylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(fluorenyl)zirconium dichloride, phenylmethylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(fluorenyl)zirconium dichloride, phenylmethylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride, phenylmethylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride chloride, phenylmethylmethylene (3-tert-butyl-5-methylcyclopentadienyl) (octamethyloctahydridodibenzfluorenyl) zirconium dichloride, and dibromide compounds, dialkyl compounds, diaralkyl compounds, disilyl compounds, dialkoxy compounds, dithiol compounds, disulfonic acid compounds, diamino compounds, diphosphine compounds, or metallocene compounds in which the metal of these compounds is titanium or hafnium.

Among these, preferred metallocene compounds include di(p-tolyl)methylene(cyclopentadienyl)(octamethyloctahydrodibenzofluorenyl)zirconium dichloride, isopropylidene(cyclopentadienyl)(fluorenyl)zirconium dichloride, isopropylidene(cyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride, and isopropylidene(cyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride. dibutylmethylene(cyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride, dibutylmethylene(cyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, dibutylmethylene(cyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride, dibutylmethylene(cyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, dibutylmethylene(cyclopentadienyl) (Octamethyloctahydridodibenzfluorenyl)zirconium dichloride, cyclohexylidene(cyclopentadienyl)(fluorenyl)zirconium dichloride, cyclohexylidene(cyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride, cyclohexylidene(cyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, cyclohexylidene(cyclopentadienyl)(octamethyloctahydridodibenz fluorenyl) zirconium dichloride, dimethylsilyl (cyclopentadienyl) (fluorenyl) zirconium dichloride, dimethylsilyl (cyclopentadienyl) (2,7-di-tert-butylfluorenyl) zirconium dichloride, dimethylsilyl (cyclopentadienyl) (3,6-di-tert-butylfluorenyl) zirconium dichloride, dimethylsilyl (cyclopentadienyl) (octamethyloctahydridodibenzfluorenyl) zirconium dichloride.

Specific examples of preferred metallocene compounds in which adjacent groups among R ¹⁵ to R ¹⁸ on the cyclopentadienyl ring are bonded to each other to form a ring and which have an indenyl ring or a substituted indenyl ring include isopropylidene(indenyl)(fluorenyl)zirconium dichloride, isopropylidene(indenyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride, isopropylidene(indenyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, isopropylidene(indenyl)(octamethyloctahydridodibenzfluorenyl)zirconium dichloride, cyclohexylidene(indenyl)(fluorenyl)zirconium dichloride, cyclohexylidene(indenyl)(2,7-di-tert dimethylsilyl(indenyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride, dimethylsilyl(indenyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, dimethylsilyl(indenyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride, dimethylsilyl(indenyl)(octamethyloctahydridodibenzfluorenyl)zirconium dichloride.

As such a bridged metallocene compound represented by formula (VIII), the compounds disclosed in WO 01/27124 may be used.

As the olefin polymerization catalyst, two or more metallocene compounds having different chemical structures among the compounds represented by formula (IV) may be used. In addition, one optical isomer may be used alone, or a mixture of optical isomers (e.g., a meso mixture or a racemic mixture) may be used.

<Co-catalyst (B)>
It is preferable that the olefin polymerization catalyst further contains at least one compound (cocatalyst (B)) selected from an organometallic compound (B-1), an organoaluminum oxy compound (B-2), and a compound (B-3) that reacts with the transition metal compound (A1) and/or the bridged metallocene compound (A2) to form an ion pair.

The organometallic compound (B-1) (excluding the organoaluminum oxy compound (B-2)) may, for example, be an organoaluminum compound, specifically an organoaluminum compound represented by the formula R ^a _m Al(OR ^b ) _n H _p X _q (wherein R ^a and R ^b may be the same or different and are a hydrocarbon group having 1 to 15, preferably 1 to 4, carbon atoms, X is a halogen atom, m is a number satisfying 0<m≦3, n is a number satisfying 0≦n<3, p is a number satisfying 0≦p<3, q is a number satisfying 0≦q<3, and m+n+p+q=3). Specific examples thereof include trialkylaluminums such as trimethylaluminum, triethylaluminum, triisobutylaluminum, and tri-normal-octylaluminum, dialkylaluminum hydrides such as diisobutylaluminum hydride, and tricycloalkylaluminums such as tricyclohexylaluminum.

The organoaluminum oxy compound (B-2) may be a conventionally known aluminoxane, or may be a benzene-insoluble organoaluminum oxy compound such as those exemplified in JP-A-2-78687. A specific example is methylaluminoxane.

As the aluminoxane, solid aluminoxanes are also preferably used, and for example, the solid aluminoxanes disclosed in WO 2010/055652, WO 2013/146337, and WO 2014-123212 are particularly preferably used.

"Solid" means that the solid aluminoxane maintains a substantially solid state in the reaction environment in which it is used. More specifically, it means that the aluminoxane is in a solid state in a specific temperature and pressure environment in an inert hydrocarbon medium such as hexane or toluene used in the reaction when, for example, the components constituting the olefin polymerization catalyst are contacted to prepare a solid catalyst component for olefin polymerization.

As the solid aluminoxane, an aluminoxane having at least one type of constituent unit selected from the constituent units represented by formula (1) and the constituent units represented by formula (2) is preferable, an aluminoxane having a constituent unit represented by formula (1) is more preferable, and a polymethylaluminoxane consisting only of the constituent units represented by formula (1) is even more preferable.

In formula (1), Me is a methyl group.

In formula (2), R ¹ is a hydrocarbon group having 2 to 20 carbon atoms, preferably a hydrocarbon group having 2 to 15 carbon atoms, and more preferably a hydrocarbon group having 2 to 10 carbon atoms. Examples of the hydrocarbon group include alkyl groups such as ethyl, propyl, n-butyl, pentyl, hexyl, octyl, decyl, isopropyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, 3-methylbutyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 2-methylhexyl, 3-methylhexyl, and 2-ethylhexyl; cycloalkyl groups such as cyclohexyl and cyclooctyl; and aryl groups such as phenyl and tolyl.

The structure of solid aluminoxane has not been clearly defined, and is generally assumed to have a structure in which the structural units represented by formula (1) and/or formula (2) are repeated about 2 to 50 times, but is not limited to this structure. The structural units may be bonded in various ways, such as linear, cyclic, or cluster-like, and the aluminoxane is generally assumed to be one of these, or a mixture of these. The aluminoxane may also be composed only of the structural units represented by formula (1) or formula (2).

As the solid aluminoxane, solid polymethylaluminoxane is preferred, and solid polymethylaluminoxane consisting only of the structural unit represented by formula (1) is more preferred.

The solid aluminoxane is usually particulate, and the volume statistical value D50 is preferably 1 to 500 μm, more preferably 2 to 200 μm, and even more preferably 5 to 50 μm. The volume statistical value D50 can be determined by a laser diffraction/scattering method using, for example, an MT3300EX II manufactured by Microtrac.

The solid aluminoxane preferably has a specific surface area of 100 to 1000 m ² /g, more preferably 300 to 800 m ² /g. The specific surface area can be determined by using the BET adsorption isotherm and utilizing the phenomenon of gas adsorption and desorption on the solid surface.

The solid aluminoxane also functions as a carrier (C). Therefore, when using solid aluminoxane, it is not necessary to use a solid inorganic carrier such as silica, alumina, silica-alumina, magnesium chloride, or a solid organic carrier such as polystyrene beads.

Solid aluminoxanes can be prepared, for example, by the methods described in WO 2010/055652 and WO 2014/123212.

Examples of the compound (B-3) that reacts with the transition metal compound (A1) and/or the bridged metallocene compound (A2) to form an ion pair include Lewis acids, ionic compounds, borane compounds, and carborane compounds described in, for example, JP-T-1-501950, JP-T-1-502036, JP-A-3-179005, JP-A-3-179006, JP-A-3-207703, JP-A-3-207704, and US Pat. No. 5,321,106. Further examples include heteropoly compounds and isopoly compounds.

<Carrier (C)>
The support (C) is preferably in the form of particles, and it is also preferable to form the olefin polymerization catalyst by immobilizing the transition metal compound (A1) and/or the bridged metallocene compound (A2) on the surface and/or inside thereof.

The carrier (C) is usually made of an inorganic or organic compound. Examples of solid inorganic carriers include carriers made of inorganic compounds such as porous oxides, inorganic halides, clays, clay minerals, and ion-exchangeable layered compounds. Examples of solid organic carriers include carriers such as polystyrene beads. Other examples of carriers (C) include the solid aluminoxanes mentioned above.

Examples _of porous oxides include oxides such as _SiO2 , _{Al2O3 ,} MgO, _ZrO2 , _TiO2 , _B2O3 , CaO, ZnO, BaO, and _ThO2 , as well as composites or mixtures containing these. Examples also include natural or synthetic zeolites, _{SiO2 - MgO} , _SiO2 - _Al2O3 , _{SiO2 -} TiO2, _{SiO2 - V2O5} , SiO2 _{- Cr2O3} , and _SiO2 - _TiO2 -MgO.

Examples of inorganic halides include MgCl ₂ , MgBr ₂ , MnCl ₂ , and MnBr _2. The inorganic halides may be used as they are, or may be used after being pulverized by a ball mill, a vibration mill, or the like. In addition, the inorganic halides may be dissolved in a solvent such as alcohol, and then precipitated into fine particles by a precipitating agent.

Clay is usually composed of clay minerals as the main component. Ion-exchangeable layered compounds are compounds having a crystal structure in which the planes formed by ionic bonds or the like are stacked in parallel with weak bonding forces, and the ions contained therein can be exchanged. Most clay minerals are ion-exchangeable layered compounds. Examples of clay, clay minerals, or ion-exchangeable layered compounds include clay, clay minerals, or ionic crystalline compounds having layered crystal structures such as hexagonal close-packed packing type, antimony type, _CdCl2 type, and _CdI2 type.

It is also preferable to subject the clay and clay minerals to chemical treatment. Any chemical treatment can be used, such as a surface treatment to remove impurities adhering to the surface, or a treatment that affects the crystal structure of the clay. Specific examples of chemical treatments include acid treatment, alkali treatment, salt treatment, and organic matter treatment.

The volume statistical value D50 of the carrier (C) is preferably 1 to 500 μm, more preferably 2 to 200 μm, and even more preferably 5 to 50 μm. The volume statistical value D50 can be determined by a laser diffraction/scattering method using, for example, an MT3300EX II manufactured by Microtrac.

<Organic Compound Component (D)>
The olefin polymerization catalyst may further contain an organic compound component (D) as required. The organic compound component (D) is used for the purpose of improving the polymerization performance and the physical properties of the resulting polymer as required. Examples of the organic compound component (D) include alcohols, phenolic compounds, carboxylic acids, phosphorus compounds, amides, polyethers, and sulfonates.

<How to use each ingredient and the order of addition>
In olefin polymerization, the method of use and the order of addition of each component may be selected arbitrarily, but the following method is exemplified: Hereinafter, the transition metal compound (A1), bridged metallocene compound (A2), cocatalyst (B), carrier (C) and organic compound component (D) are also referred to as "components (A1) to (D)", respectively.
(i) A method in which the components (A1) to (C) are added to a polymerization tank in any order.
(ii) A method in which a catalyst component in which components (A1) to (A2) are supported on component (C) is added to a polymerization tank.

In each of the above methods (i) to (ii), component (D) may be added at any stage. In addition, at least two of the catalyst components may be in contact with each other in advance.

Since the present invention involves slurry polymerization, it is preferable to obtain a solid catalyst component by contacting at least components (A1), (A2) and (C) in an inert hydrocarbon medium, and then supply the solid catalyst component to a polymerization tank.

In addition, antistatic agents, antifouling agents and/or surfactants can be used to facilitate smooth polymerization.

In steps (1) and (2), when a monomer such as ethylene is polymerized using an olefin polymerization catalyst, the amounts of each component that may constitute the catalyst are as follows. Hereinafter, the transition metal compound (A1), bridged metallocene compound (A2), and (B-1) to (B-3) exemplified in the cocatalyst (B) column are also referred to as component (A1), component (A2), and components (B-1) to (B-3), respectively.

Component (A1) can be supplied to step (1) in an amount that is typically 0.001 to 1.00 mmol/hr, preferably 0.005 to 0.50 mmol/hr, and more preferably 0.010 to 0.30 mmol/hr, calculated as the transition metal atom (M, i.e., transition metal atom of Group 4 of the periodic table) in component (A1).

Component (A2) can be supplied to step (1) in an amount that is typically 0.001 to 1.00 mmol/hr, preferably 0.005 to 0.50 mmol/hr, and more preferably 0.010 to 0.30 mmol/hr, calculated as the transition metal atoms (M, i.e., transition metal atoms of Groups 3 to 11 of the Periodic Table) in component (A2).

Component (B-1) can be used in an amount such that the molar ratio [(B-1)/M] of component (B-1) to the transition metal atoms (M) in components (A1) and (A2) is usually 10 to 10,000, preferably 30 to 2,000, and more preferably 50 to 1,000.

Component (B-2) can be used in an amount such that the molar ratio [Al/M] of aluminum atoms (Al) in component (B-2) to transition metal atoms (M) in components (A1) and (A2) is usually 10 to 10,000, preferably 30 to 2,000, and more preferably 50 to 1,000.

Component (B-3) can be used in an amount such that the molar ratio [(B-3)/M] of component (B-3) to the transition metal atoms (M) in components (A1) and (A2) is usually 1 to 10,000, preferably 2 to 2,000, and more preferably 10 to 500.

The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples.

The physical properties in the following examples were measured and evaluated as follows:

<Intrinsic viscosity [η]>
The intrinsic viscosity [η] of the ethylene polymer in the content extracted from the first polymerization vessel described below and the finally obtained ethylene polymer were measured at 135° C. using decalin.
Specifically, about 20 mg of each sample was dissolved in 15 ml of decalin, and the specific viscosity η _sp was measured in an oil bath at 135° C. The decalin solution was diluted with 5 ml of decalin, and the specific viscosity η _sp was measured in the same manner. This dilution procedure was repeated two more times, and the value of η _sp /C when the concentration (C) was extrapolated to 0 was calculated as the limiting viscosity [η] (see the following formula).
[η] = lim (η _sp / C) (C → 0)

<Polymerization ratio of ethylene-based polymer (e1) to ethylene-based polymer (e2)>
From the molecular weight curve of the finally obtained ethylene-based polymer (E), peak curves attributable to the ethylene-based polymer (e1) polymerized in the first polymerization tank described below and the ethylene-based polymer (e2) polymerized in the second polymerization tank described below were separated, and the polymerization amount ratio (mass ratio) of the ethylene-based polymers (e1) and (e2) was calculated from each peak curve. Specifically, it was calculated as follows.

The molecular weight curve of the finally obtained ethylene polymer (E) was measured using GPC-150C manufactured by Waters Corporation as follows.
As the separation columns, TSKgel GMH6-HT and TSKgel GMH6-HTL (column size: inner diameter 7.5 mm, length 600 mm, respectively) were used, the column temperature was 140°C, o-dichlorobenzene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used as the mobile phase and 0.025 mass% BHT (manufactured by Takeda Pharmaceutical Co., Ltd.) was used as the antioxidant, the mobile phase was moved at 1.0 ml/min, the sample concentration was 0.1 mass%, the sample injection amount was 500 μl, and a differential refractometer was used as the detector. In addition, as the standard polystyrene, when the molecular weight was Mw<1,000 and Mw>4×10 ⁶ , standard polystyrene manufactured by Tosoh Corporation was used, and when the molecular weight was 1,000≦Mw≦4×10 ⁶ , standard polystyrene manufactured by Pressure Chemical Co., Ltd. was used. The molecular weight was calculated by universal calibration and converted to polyethylene.

From the molecular weight curve of the finally obtained ethylene polymer (E), peak curves originating from the ethylene polymers (e1) and (e2) were separated. The peak curves were separated based on a program created using Microsoft Excel Visual Basic. The two peak curves to be separated were assumed to be log-normal distributions, and the molecular weight distribution curve was separated into two peak curves with different molecular weights by convergence calculation. The curve obtained by recombining the two separated peak curves was compared with the molecular weight curve actually measured by the GPC method, and calculations were performed while changing the initial value so that the two curves were almost identical. The calculation was performed by dividing Log (molecular weight) into 0.02 intervals, and normalizing the intensity so that the area of the measured molecular weight curve and the area of the curve obtained by recombining the two separated peak curves were 1.

<Intrinsic viscosity [η] of ethylene polymer (e2)>
The intrinsic viscosity [η] of the ethylene polymer (e2) was calculated from the values of the intrinsic viscosities [η] of the ethylene polymer (e1) polymerized in the first polymerization tank and the finally obtained ethylene polymer (E) measured as described above, and the mass ratio of the ethylene polymer (e1) to the ethylene polymer (e2) determined as described above.
Specifically, when the [η] of the ethylene polymers (e1) and (e2) and the ethylene polymer (E) are respectively [η] ₁ , [η] ₂ and [η] _t , and the mass proportions of the ethylene polymers (e1) and (e2) are respectively _w1 and _w2 (where _w1 + _w2 = 1), the intrinsic viscosity [η] of the ethylene polymer (e2) can be calculated by the following formula.
[η] ₂ = ([η] _t - _w1 · [η] ₁ ) / _w2

<MFR>
Using the following evaluation samples, MFR was measured under conditions of a temperature of 190° C. and a load of 2.16 kg in accordance with ASTM D-1238-89.

<Density>
The density of the ethylene-based polymer in the content discharged from the first polymerization vessel and the finally obtained ethylene-based polymer were measured. Specifically, each polymer was heat-treated at 120° C. for 1 hour, slowly cooled linearly to room temperature over 1 hour, and then its density was measured using a density gradient tube in accordance with JIS K 7112.

<Density of Ethylene-Based Polymer (e2)>
The density of the ethylene-based polymer (e2) was calculated from the values of the densities of the ethylene-based polymer (e1) polymerized in the first polymerization tank and the finally obtained ethylene-based polymer (E) measured as described above, and the mass ratio of the ethylene-based polymer (e1) to the ethylene-based polymer (e2) determined as described above.
Specifically, when the densities of the ethylene polymers (e1) and (e2) and the ethylene polymer (E) are _D1 , _D2 and _Dt , respectively, and the mass proportions of the ethylene polymers (e1) and (e2) are _w1 and _w2 , respectively (where _w1 + _w2 = 1), the density of the ethylene polymer (e2) can be calculated by the following formula.
_D2 = ( _Dt - _w1 x _D1 ) / _w2

<Press sheet properties>
Preparation of Press Sheet Using a hydraulic hot press machine manufactured by Shinto Metal Industry Co., Ltd. set at 190°C, the following evaluation sample was pressed at a pressure of 100 kg/ ^cm2 to form a sheet having a thickness of 4 mm. The obtained sheet was then cooled by pressing at a pressure of 100 kg/ ^cm2 using another hydraulic hot press machine manufactured by Shinto Metal Industry Co., Ltd. set at 20°C to prepare a press sheet.

<Flexural modulus of press sheet>
In accordance with the description in the section on flexural modulus in "General properties and test conditions" in Table 3 of JIS K 6922-2, the flexural modulus of the press sheet was measured in accordance with the method for determining flexural properties described in JIS K 7171. The results are shown in Table 1.

<Tensile impact strength of press sheet>
The tensile impact strength of the press sheet was measured according to the test method of JIS K 7160 (ISO 8256) in accordance with the description in the section on tensile impact strength (notched) in Table 3 "General properties and test conditions" of JIS K6922-2. The results are shown in Table 1.

<Bottle Evaluation>
Using the evaluation samples described below, blow molding was carried out under the molding conditions described below to prepare cylindrical bottles having a capacity of 1.0 L and a mass of 50 g.
Molding machine: MSE-50 (manufactured by Tahara Co., Ltd.)
Cylinder temperature setting: 180℃
Die setting temperature: 180°C
Mold temperature: 25°C
Extrusion speed: 9 kg/h
Die diameter/core diameter: 27mm/25mm

The average surface roughness Ra of the skin of the produced bottle (the inner surface of the bottle) was measured using a surface roughness and shape measuring instrument Surfcom 1400D manufactured by Tokyo Seimitsu Co., Ltd. The measurement length was 4.0 mm, the measurement speed was 0.6 mm/s, and the average value of three measurements is shown in Table 1.

[Preparation Example 1] Preparation of solid catalyst component (γ1) According to [Synthesis Example 1] [Preparation of solid carrier (X-1)] in JP 2017-25160 A, a solid carrier-containing slurry was obtained. 2.00 L of toluene was charged into a reactor at room temperature (20 to 25°C) that had been fully substituted with nitrogen, and 18.62 mol (20.73 L) of the solid carrier-containing slurry was charged in terms of aluminum atoms, and the suspension was stirred for 10 minutes.

Next, 6.4 mmol of the compound represented by the following formula (A1-1), which was synthesized based on JP 2017-25161 A, was dissolved in 2.00 L of a toluene solution, added to the reactor, and stirred for 30 minutes. Thereafter, 64.2 mmol of the compound represented by the following formula (A2-1) was dissolved in 2.00 L of a toluene solution, added to the reactor, and stirred for 60 minutes to obtain a slurry containing a solid catalyst component (γ1).

Preparation Example 2 Preparation of solid catalyst component (γ2) Into a reactor at room temperature (20 to 25° C.) that had been thoroughly purged with nitrogen, 53.0 L of toluene was charged, and 4.94 mol (5.50 L) of the solid carrier-containing slurry was charged in terms of aluminum atom, and the suspension was stirred for 10 minutes.
Next, 29.0 mmol of the compound represented by the formula (A2-1) was dissolved in 2.00 L of a toluene solution, added to the reactor, and then stirred for 60 minutes to obtain a slurry containing a solid catalyst component (γ2).

[Example 1]
Step (1)
To the first polymerization tank, hexane was continuously supplied at 54.0 L/hr, the slurry containing the solid catalyst component (γ1) was supplied at 0.066 mmol/hr calculated as zirconium atom, triisobutylaluminum was supplied at 11.9 mmol/hr, ethylene was supplied at 7.60 kg/hr, hydrogen molecules was supplied at 50.0 NL/hr, and Adeka Pluronic L-71 (manufactured by ADEKA CORPORATION, hereinafter referred to as "L-71") was supplied at 0.600 g/hr. While continuously withdrawing the contents of the polymerization tank so that the liquid level in the polymerization tank was kept constant, polymerization was carried out under the conditions of a polymerization temperature of 80.3° C., a reaction pressure of 0.72 MPaG, and an average residence time of 2.60 hr, to obtain an ethylene-based polymer.
In a flash drum maintained at an internal pressure of 0.030 MPaG and at 40.0° C., unreacted ethylene and hydrogen molecules in the content continuously discharged from the first polymerization vessel were substantially removed.

Step (2)
The content from which the unreacted ethylene and hydrogen molecules had been substantially removed was continuously supplied to a second polymerization tank at a rate of 70.5 L/hr, together with 31.0 L/hr of hexane, 3.30 kg/hr of ethylene, 2.0 NL/hr of hydrogen molecules, 0.25 g/hr of L-71, and 100 g/hr of 1-hexene, and polymerization was subsequently carried out under conditions of a polymerization temperature of 74.9° C., a reaction pressure of 0.28 MPaG, and an average residence time of 1.6 hr.
The contents of the second polymerization vessel were continuously withdrawn so that the liquid level in the vessel was constant. In order to prevent unintended polymerization, methanol was supplied to the contents withdrawn from the second polymerization vessel at 2.50 L/hr to deactivate the solid catalyst component. Thereafter, hexane and unreacted monomers in the contents from which the solid catalyst component had been deactivated were removed by a solvent separator, and the contents were dried to obtain an ethylene polymer (E-1).

<Preparation of evaluation samples>
Relative to 100 parts by mass of the obtained ethylene-based polymer (E-1), 1500 ppm of Irgafos168 (manufactured by BASF Japan Ltd., tris(2,4-di-tert-butylphenyl) phosphite) as a heat stabilizer, 1000 ppm of Irganox3114 (manufactured by BASF Japan Ltd., tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate) as a heat stabilizer, 1300 ppm of Electrostripper (manufactured by Kao Corporation, lauryldiethanolamine) as an antistatic agent, and 500 ppm of calcium stearate (manufactured by Nitto Kasei Kogyo Co., Ltd.) were blended. Thereafter, the mixture was melt-kneaded using a Placo single-screw extruder (screw diameter 65 mm, L/D = 28, screen mesh 40/60/500 x 3/60/40) at a set temperature of 200°C and a resin extrusion rate of 30 kg/hr, and then extruded into strands, which were then cut to prepare pellets (evaluation samples).

[Example 2]
Step (1)
To the first polymerization tank, hexane was continuously supplied at 54.0 L/hr, the slurry containing the solid catalyst component (γ1) at 0.066 mmol/hr calculated as zirconium atom, triisobutylaluminum at 11.8 mmol/hr, ethylene at 7.60 kg/hr, hydrogen molecules at 50.0 NL/hr, and L-71 at 0.60 g/hr, and while the content of the polymerization tank was continuously discharged so that the liquid level in the polymerization tank was constant, polymerization was carried out under the conditions of a polymerization temperature of 79.8° C., a reaction pressure of 0.72 MPaG, and an average residence time of 2.60 hr, to obtain an ethylene-based polymer.
In a flash drum maintained at an internal pressure of 0.030 MPaG and at 40.0° C., unreacted ethylene and hydrogen molecules in the content continuously discharged from the first polymerization vessel were substantially removed.

Step (2)
The content from which the unreacted ethylene and hydrogen molecules had been substantially removed was continuously supplied to a second polymerization tank at a rate of 67.8 L/hr, together with 31.0 L/hr of hexane, 3.30 kg/hr of ethylene, 2.00 NL/hr of hydrogen molecules, 0.25 g/hr of L-71, and 100 g/hr of 1-hexene, and polymerization was subsequently carried out under conditions of a polymerization temperature of 74.9° C., a reaction pressure of 0.26 MPaG, and an average residence time of 1.6 hr.
The contents of the second polymerization vessel were continuously withdrawn so that the liquid level in the vessel was also constant. In order to prevent unintended polymerization, methanol was supplied to the contents withdrawn from the second polymerization vessel at 2.50 L/hr to deactivate the solid catalyst component. Thereafter, hexane and unreacted monomers in the contents from which the solid catalyst component had been deactivated were removed by a solvent separator, and the contents were dried to obtain an ethylene polymer (E-2).
An evaluation sample was prepared in the same manner as in Example 1 using the obtained ethylene polymer (E-2).

[Comparative Example 1]
Step (1)
To the first polymerization tank, hexane was continuously supplied at 54.0 L/hr, the slurry containing the solid catalyst component (γ2) at 0.052 mmol/hr calculated as zirconium atom, triisobutylaluminum at 11.9 mmol/hr, ethylene at 8.00 kg/hr, hydrogen molecules at 62.1 NL/hr, and L-71 at 0.600 g/hr, and polymerization was carried out under the conditions of a polymerization temperature of 80.1° C., a reaction pressure of 0.73 MPaG, and an average residence time of 2.60 hr, while the content of the polymerization tank was continuously discharged so that the liquid level in the polymerization tank was constant, to obtain an ethylene-based polymer.
In a flash drum maintained at an internal pressure of 0.030 MPaG and at 40.0° C., unreacted ethylene and hydrogen molecules in the content continuously discharged from the first polymerization vessel were substantially removed.

Step (2)
The content from which the unreacted ethylene and hydrogen molecules had been substantially removed was continuously supplied to a second polymerization tank at a rate of 71.8 L/hr, together with 31.0 L/hr of hexane, 3.40 kg/hr of ethylene, 2.30 NL/hr of hydrogen molecules, 0.30 g/hr of L-71, and 105 g/hr of 1-hexene, and polymerization was subsequently carried out under conditions of a polymerization temperature of 74.4° C., a reaction pressure of 0.26 MPaG, and an average residence time of 1.6 hr.
The contents of the second polymerization vessel were continuously discharged so that the liquid level in the vessel was kept constant. In order to prevent unintended polymerization, such as the production of a polymer containing a large amount of 1-hexene, methanol was supplied to the contents discharged from the second polymerization vessel at 2.50 L/hr to deactivate the solid catalyst component. Thereafter, hexane and unreacted monomers in the contents from which the solid catalyst component had been deactivated were removed by a solvent separator, and the contents were dried to obtain an ethylene polymer (cE-1).
An evaluation sample was prepared in the same manner as in Example 1 using the obtained ethylene polymer (cE-1).

[Comparative Example 2]
Step (1)
To the first polymerization tank, hexane was continuously supplied at 54.0 L/hr, the slurry containing the solid catalyst component (γ2) at 0.052 mmol/hr calculated as zirconium atom, triisobutylaluminum at 11.7 mmol/hr, ethylene at 8.00 kg/hr, hydrogen molecules at 52.5 NL/hr, and L-71 at 0.600 g/hr, and polymerization was carried out under the conditions of a polymerization temperature of 80.0° C., a reaction pressure of 0.72 MPaG, and an average residence time of 2.60 hr, while the content of the polymerization tank was continuously discharged so that the liquid level in the polymerization tank was constant, to obtain an ethylene-based polymer.
In a flash drum maintained at an internal pressure of 0.030 MPaG and a temperature of 40.0° C., unreacted ethylene and hydrogen molecules in the content continuously discharged from the first polymerization vessel were substantially removed.

Step (2)
The content from which the unreacted ethylene and hydrogen molecules had been substantially removed was continuously supplied to a second polymerization tank at a rate of 73.0 L/hr, together with 31.0 L/hr of hexane, 3.40 kg/hr of ethylene, 1.6 NL/hr of hydrogen molecules, 0.25 g/hr of L-71, and 85 g/hr of 1-hexene, and polymerization was subsequently carried out under conditions of a polymerization temperature of 74.4° C., a reaction pressure of 0.26 MPaG, and an average residence time of 1.6 hr.
The contents of the second polymerization vessel were continuously discharged so that the liquid level in the vessel was kept constant. In order to prevent unintended polymerization, such as the production of a polymer containing a large amount of 1-hexene, methanol was supplied to the contents discharged from the second polymerization vessel at 2.50 L/hr to deactivate the solid catalyst component. Thereafter, hexane and unreacted monomers in the contents from which the solid catalyst component had been deactivated were removed by a solvent separator, and the contents were dried to obtain an ethylene polymer (cE-2).
An evaluation sample was prepared in the same manner as in Example 1 using the obtained ethylene polymer (cE-2).

[Reference Example 1]
An evaluation sample was prepared in the same manner as in Example 1 using Hi-Zex 6008B manufactured by Prime Polymer Co., Ltd.

As shown in Table 1, the bottles obtained in Examples 1 and 2 were found to have a smaller average surface roughness Ra and a better appearance than the bottles obtained in Comparative Examples 1 and 2.

Claims (4)

A method for continuously producing an ethylene polymer (E),
a step (1) of producing an ethylene polymer (e1) having an intrinsic viscosity [η] of 0.5 to 1.5 dl/g as measured in decalin at 135° C. by a slurry polymerization method in the presence of an olefin polymerization catalyst comprising a transition metal compound (A1) represented by formula (I) and a bridged metallocene compound (A2) represented by formula (IV), in an amount of 20 to 80 mass % of the finally obtained ethylene polymer (E);
a step (2) of producing an ethylene polymer (e2) having an intrinsic viscosity [η] of 3.0 to 10.0 dl/g as measured in decalin at 135° C. by a slurry polymerization method in the presence of the ethylene polymer (e1) obtained in the step (1), in an amount of 20 to 80 mass% of the finally obtained ethylene polymer (E);
Including,
The slurry containing the ethylene polymer (e1) and the olefin polymerization catalyst obtained in the step (1) is continuously supplied to the step (2).
A method for producing an ethylene polymer (E).
[In formula (I),
M is a transition metal atom of Group 4 of the periodic table;
m is an integer from 1 to 4,
R ¹ to R ⁵ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing group, two or more of which may be linked to each other to form a ring, and when m is 2 or more, at least two of the groups represented by R ¹ to R ⁵ may be linked to each other;
R ⁶ is a group represented by the formula C _n' H _2n'+1 (n' is an integer from 1 to 8), the formula (II) or the formula (III);
j is a number that satisfies the valence of M;
X is a hydrogen atom, a halogen atom, a hydrocarbon group or a heteroatom-containing group, and when j is 2 or more, the groups represented by X may be the same or different from each other, and the groups represented by X may be bonded to each other to form a ring, and the ring formed by bonding the heteroatom-containing group and the groups represented by X to each other is other than the group represented by the following formula (i) .
[In the formula (II),
R ⁷ and R ¹¹ are hydrogen atoms;
R ⁸ to R ¹⁰ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group, or a heteroatom-containing group, and two or more of R ⁸ to R ¹⁰ may be bonded to each other to form a ring;
The filled circle (●) is the point of attachment to the nitrogen atom in formula (I).
[In the formula (III),
R ¹² and R ¹⁵ are hydrogen atoms, and R ¹² and R ¹⁵ are bonded to carbon atoms constituting a ring bonded to the carbon atom bonded to the black circle (●),
R ¹³ is a divalent saturated hydrocarbon group having 3 to 8 carbon atoms;
R ¹⁴ is a halogen atom, a hydrocarbon group, or a heteroatom-containing group;
n is 0 or an integer equal to or less than twice the number of carbon atoms of R ¹³ , and when n is an integer equal to or greater than 2, a plurality of R ¹⁴ may be the same or different from each other;
The filled circle (●) is the point of attachment to the nitrogen atom in formula (I).
[In formula (IV),
M is a transition metal atom of Groups 3 to 11 of the periodic table;
^Cp1 and ^Cp2 are each independently a cyclopentadienyl group or a substituted cyclopentadienyl group capable of forming a sandwich structure together with M;
j is an integer from 1 to 4,
Q represents a hydrogen atom, a halogen atom, a hydrocarbon group or a heteroatom-containing group, and when j is 2 or more, the groups represented by Q may be the same or different, and the groups represented by Q may be bonded to each other to form a ring;
Y is a divalent hydrocarbon group having 1 to 30 carbon atoms, a divalent halogenated hydrocarbon group having 1 to 20 carbon atoms, a divalent silicon-containing group, a divalent germanium-containing group, a divalent tin-containing group, -O-, -CO-, -S-, -SO-, -SO ₂ -, -Ge-, -Sn-, -NR ^a -, -P(R ^a )-, -P(O)(R ^a )-, -BR ^{a - or -AlR a -} (wherein R ^a is a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, a hydrogen atom, a halogen atom, -NRH or -NR ₂ (wherein R is independently a hydrocarbon group having 1 to 20 carbon atoms)).
[In formula (i), R ¹ to R ⁶ each independently have the same meaning as R ¹ to R ⁶ in formula (I) above , and are bonded to M at *.] The method for producing an ethylene-based polymer (E) according to claim 1, wherein the ethylene-based polymer (E) has an intrinsic viscosity [η] of 1.0 to 6.0 dl/g as measured in decalin at 135°C. The method for producing an ethylene-based polymer (E) according to claim 1 or 2, wherein the melt flow rate (MFR) of the ethylene-based polymer (E) measured under conditions of a temperature of 190°C and a load of 2.16 kg is 0.01 to 5.0 g/10 min. The method for producing an ethylene-based polymer (E) according to any one of claims 1 to 3, wherein the ethylene-based polymer (E) has a density of 950 to 975 kg/ ^m3 .