Polyethylene powder and its manufacturing method, and olefin polymerization catalyst and its manufacturing method

Abstract

This polyethylene powder has a viscosity-average molecular weight of 100,000 to 4,000,000, and is configured such that the crystal thickness parameter obtained from measurement using a differential scanning calorimeter (DSC) is 5°C to 9°C.

Description

[Technical Field]

[0001] The present invention relates to polyethylene powder, a method for producing the same, and a catalyst for olefin polymerization and a method for producing the same. [Background technology]

[0002] Ethylene polymers are used in a wide variety of applications, including films, sheets, microporous membranes, fibers, foams, and pipes. The reasons for using ethylene polymers include their ease of melt processing, and the resulting molded products possessing high mechanical strength, excellent chemical resistance, and rigidity. Among these, ultra-high molecular weight ethylene polymers, due to their larger molecular weight, exhibit even higher mechanical strength, superior sliding properties and wear resistance, and excellent chemical stability and long-term reliability. For these reasons, ultra-high molecular weight polyethylene powder is particularly used as a raw material for microporous membranes in secondary battery separators, such as those found in lead-acid and lithium-ion batteries.

[0003] Various ethylene polymers with improved properties have been proposed as raw materials for microporous membranes used in secondary battery separators and the like. For example, Patent Document 1 proposes an ethylene polymer that can provide molded articles (e.g., stretched molded articles, microporous membranes) with excellent oxidation resistance and shrinkage resistance, provided that the intrinsic viscosity is within a predetermined range and the proportion of the heat of fusion obtained by specific measurement conditions of a differential scanning calorimeter (DSC) is above a specific lower limit. Also, for example, Patent Document 2 proposes a method for producing a supported metallocene catalyst and a method for producing polyolefins using the same, which can produce polyolefin polymers with improved apparent density while maintaining the properties of a highly active catalyst. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 6383479 [Patent Document 2] Special Publication No. 2017-518423 [Overview of the project] [Problems that the invention aims to solve]

[0005] In recent years, the demands for microporous membranes used in secondary battery separators have been rapidly increasing, requiring further advancements in the properties of polyethylene. Specifically, there is a need for polyethylene that can provide microporous membranes with excellent heat resistance, membrane uniformity, dimensional stability, and high heat resistance, but the polyethylenes described in Patent Documents 1 and 2 have room for improvement in terms of these properties.

[0006] The present invention has been made in view of the above circumstances, and aims to provide polyethylene powder that, for example, when used as a microporous membrane, exhibits excellent heat resistance, membrane uniformity, dimensional stability, and high heat resistance. [Means for solving the problem]

[0007] As a result of diligent research to solve the aforementioned problems, the present inventors have discovered that by controlling predetermined physical properties within a specific range in polyethylene powder with a predetermined viscosity-average molecular weight, it is possible to provide a microporous film with excellent heat resistance, film uniformity, dimensional stability, and high heat resistance, thus completing the present invention.

[0008] In other words, the present invention is as follows. [1] The viscosity-average molecular weight is between 100,000 and 4,000,000. Polyethylene powder in which the crystal thickness parameter obtained from measurements using differential scanning calorimeter (DSC) is between 5°C and 9°C. [2] z-mean contraction factor g is measured by a gel permeation chromatography (GPC) analyzer that combines a differential refractometer and a viscodetector. z The polyethylene powder described in [1], wherein the value of is between 0.600 and 1. [3] Using a differential scanning calorimeter (DSC), in the DSC curve of the second heating process obtained by the measurement described in <Measurement Conditions> below, the peak top temperature (Tm2) top ) is between 135°C and 140°C, <Measurement conditions> (1) Leave standing at 50°C for 1 minute. (2) Increase the temperature from 50°C to 180°C at a rate of 10°C / min (first heating process) (3) Let stand at 180°C for 5 minutes. (4) Cool from 180°C to 50°C at 10°C / min (5) Let stand at 50°C for 5 minutes. (6) Increase the temperature from 50°C to 180°C at a rate of 10°C / min (second heating process) The polyethylene powder according to [1], wherein the crystal thickness parameter is 6.7°C or higher and 9.0°C or lower. [4] Polyethylene powder according to any of [1] to [3], which can be stretched under the following conditions; (Stretching conditions) A 100mm x 100mm x 1mm thick gel sheet, consisting of 30% by mass polyethylene powder and 70% by mass liquid paraffin, is stretched 7 x 7 times at 115°C. [5] In terahertz measurement, 400 cm -1 ~450cm -1 A polyethylene powder according to any of [1] to [4], wherein the absorption coefficient in [1] is 1.0 or greater and 4.0 or less. [6] 1 A polyethylene powder according to any of [1] to [5], wherein no peaks are present in the region shown below in 1H-NMR measurements. (1) 4.8 ppm ~ 5.0 ppm (2) 5.6 ppm ~ 6.0 ppm [7] Polyethylene powder as described in any of [1] to [6], having an aluminum content of 0 ppm or more and 50 ppm or less. [8] A polyethylene powder according to any of [1] to [7], having a silicon content of 0 ppm or more and 30 ppm or less. [9] The polyethylene powder according to [1] or [2], wherein, in differential scanning calorimeter (DSC) measurements, the peak top temperature in the DSC curve of the second heating process is 130°C or higher and 140°C or lower.

[10] Density is 920 kg / m³ 3 More than 960kg / m 3 The polyethylene powder described in any of the following [1] to [9].

[11] Polyethylene powder for use as a battery separator, as described in any of [1] to

[10] .

[12] A first supporting reaction step involves reacting inorganic solid particles [A] with a transition metal compound [B-1] and / or a transition metal compound component [B-2] and an activator [C] and / or an organometallic compound component [D], The process includes a second supporting reaction step in which the particles obtained in the first supporting reaction step are reacted with a transition metal compound component [B-1] and / or a transition metal compound component [B-2] and an activator [C] and / or an organometallic compound component [D]. The transition metal compound [B-1] is a compound represented by the following (Formula 3), the transition metal compound [B-2] is a compound represented by the following (Formula 4), the activator [C] is a compound represented by the following (Formula 5) or (Formula 6), the organometallic compound component [D] is a compound containing at least one metal selected from the group consisting of Groups 1, 2, 12 and 13 of the periodic table, and the inorganic solid particles [A] are porous polymer materials or inorganic solid particles containing at least one element selected from the group consisting of Groups 2 to 4, 13 and 14 of the periodic table. A method for producing a catalyst for olefin polymerization that satisfies the following conditions 1 and / or 2. <Condition 1> In the first supported reaction step, a pre-mixing step of reacting a transition metal compound [B-1] and / or a transition metal compound component [B-2] with an activator [C] and / or an organometallic compound component [D], and a step of reacting the inorganic solid particles [A] with the mixture obtained in the pre-mixing step are included. <Condition 2> In the first supported reaction step, the molar ratio (([C]+[D]) / [B]) of the molar amount ([C]+[D]) of the activator [C] and the organometallic compound component [D] to the molar amount [B] of the transition metal compound component [B-1] and / or the transition metal compound component [B-2] is 1 or more and 60 or less. L 1 j W k M 1 X 1 p X 2 q ···(Formula 3) (In the formula, L 1 each independently represents an η-bonded cyclic anion ligand selected from the group consisting of a cyclopentadienyl group, an indenyl group, a tetrahydroindenyl group, a fluorenyl group, a tetrahydrofluorenyl group, and an octahydrofluorenyl group, and the ligand may have 1 to 8 substituents, and each of the substituents is independently a hydrocarbon group having 1 to 20 carbon atoms, a halogen atom, a halogen-substituted hydrocarbon group having 1 to 12 carbon atoms, an aminohydrocarbyl group having 1 to 12 carbon atoms, a hydrocarbyloxy group having 1 to 12 carbon atoms, a dihydrocarbylamino group having 1 to 12 carbon atoms, a hydrocarbylphosphino group having 1 to 12 carbon atoms, a silyl group, an aminosilyl group, a hydrocarbyloxysilyl group having 1 to 12 carbon atoms, and a halosilyl group, and is a substituent having up to 20 non-hydrogen atoms selected from the group consisting of M 1 represents a transition metal selected from the group of transition metals belonging to Group 4 of the periodic table having a formal oxidation number of +2, +3 or +4, and is a transition metal η5-bonded to at least one ligand L. W is a divalent substituent having up to 50 non-hydrogen atoms, and is bonded to L and M with a valence of one each, and thereby represents a divalent substituent that cooperates with L and M to form a metallacycle. X1 Each of these independently represents an anionic σ-bond ligand having up to 60 non-hydrogen atoms, selected from the group consisting of a monovalent anionic σ-bond ligand, a divalent anionic σ-bond ligand that bonds to M in a divalent state, and a divalent anionic σ-bond ligand that bonds to L and M with a 1-valent state each. X 2 Each of these independently represents a neutral Lewis base coordinating compound having up to 40 non-hydrogen atoms. j is 1 or 2, however when j is 2, in some cases two ligands L are bonded to each other via a divalent group having up to 20 nonhydrogen atoms, the divalent group being selected from the group consisting of a C1-C20 hydrocarbadiyl group, a C1-C12 halohydrocarbadiyl group, a C1-C12 hydrocarbyleneoxy group, a C1-C12 hydrocarbyleneamino group, a silanediyl group, a halosilanediyl group, and a silyleneamino group, k is 0 or 1, and p is 0, 1 or 2, however X 1 If is a monovalent anionic σ-bond ligand, or a divalent anionic σ-bond ligand bonded to L and M, then p is an integer less than or equal to 1 the formal oxidation number of M, and X 1 If is a divalent anionic σ-bond ligand bonded only to M, then p is an integer less than or equal to (j+1) the formal oxidation number of M, and q is 0, 1, or 2. [ka] (In the formula, M 2 This represents a transition metal selected from the group consisting of titanium, zirconium, and hafnium, whose formal oxidation number is +2, +3, or +4. R 5 Each of these independently represents a substituent having 1 to 20 non-hydrogen atoms, selected from the group consisting of hydrogen atoms, hydrocarbon groups having 1 to 8 carbon atoms, silyl groups, germyl groups, cyano groups, halogen atoms, and composite groups thereof, provided that the substituent R 5 When is a hydrocarbon group having 1 to 8 carbon atoms, a silyl group, or a gelmyl group, there may be two adjacent substituents R 5These two atoms bond to each other to form a divalent group, thereby the two adjacent substituents R 5 The bonds between the two carbon atoms of the cyclopentadienyl rings bonded to each of them cooperate to form rings, X 3 Each of these independently represents a substituent having 1 to 20 nonhydrogen atoms, selected from the group consisting of halides, hydrocarbon groups having 1 to 20 carbon atoms, hydrocarbyloxy groups having 1 to 18 carbon atoms, hydrocarbylamino groups having 1 to 18 carbon atoms, silyl groups, hydrocarbylamide groups having 1 to 18 carbon atoms, hydrocarbylphosphine groups having 1 to 18 carbon atoms, hydrocarbyl sulfide groups having 1 to 18 carbon atoms, and composite groups thereof, provided that there may be two substituents X. 3 These groups cooperate to form a neutral conjugated diene or divalent group with 4 to 30 carbon atoms. Y 1 -O-, -S-, -NR 6 - or -PR 6 - represents, however, R 6 This represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, a hydrocarbyloxy group having 1 to 8 carbon atoms, a silyl group, an alkyl halide having 1 to 8 carbon atoms, an aryl halide having 6 to 20 carbon atoms, or a composite group thereof. Z 1 is SiR 6 2. CR 6 2. SiR 6 2SiR 6 2. CR 6 2CR 6 2. CR 6 =CR 6 , CR 6 2SiR 6 2 or GeR 6 Represents 2, however R 6 As defined above, n is 1, 2, or 3. (C-1):[L 2 -H] d+ [M 3 r Q s ] d- ...(Formula 5) (In the formula, [L 2 -H] d+It is a proton-donating Brønsted acid, L 2 [M is a neutral Lewis base. Also, in the formula, [M 3 r Q s ] d- M is a compatible non-coordinating anion. 3 Q is a metal or metalloid selected from groups 5 through 15 of the periodic table, and each Q is independently a hydride, dialkylamide group, halide, alkoxide group, allinoxide group, hydrocarbon group, or substituted hydrocarbon group with up to 20 carbon atoms. Furthermore, there is no more than one halide Q. Also, r is an integer from 1 to 7, s is an integer from 2 to 14, and d is an integer from 1 to 7, with sr = d. (C-2):-(M 4 R 7 t-2 -O) u -...(Formula 6) (In the formula, M 4 These are metals or metalloids from groups 13 to 15 of the periodic table, and R 7 Each of these is independently a hydrocarbon group or substituted hydrocarbon group having 1 to 12 carbon atoms, and t is a metal M 4 (This is the valence of , where u is an integer greater than or equal to 2.)

[13] The method for producing an olefin polymerization catalyst according to

[12] , wherein the inorganic solid particles [A] are magnesium chloride particles.

[14] It comprises inorganic solid particles [A], a transition metal compound component [B-1] and / or a transition metal compound component [B-2], and an activator [C] and / or an organometallic compound component [D]. The transition metal compound [B-1] is a compound represented by the following (Formula 3), the transition metal compound [B-2] is a compound represented by the following (Formula 4), the activator [C] is a compound represented by the following (Formula 5) or (Formula 6), the organometallic compound component [D] is a compound containing at least one metal selected from the group consisting of Groups 1, 2, 12 and 13 of the periodic table, and the inorganic solid particles [A] are porous polymer materials or inorganic solid particles containing at least one element selected from the group consisting of Groups 2 to 4, 13 and 14 of the periodic table. A catalyst for olefin polymerization, wherein the content (mol) of central metal M contained in the transition metal compound component [B-1] and / or the transition metal compound component [B-2] is 20 μmol or more and 1000 μmol or less, and the molar ratio (Al / M) of the content (mol) of central metal M to the content (mol) of Al is 1 or more and 30 or less. L 1 j W k M 1 X 1 p X 2 q ...(Formula 3) (In the formula, L 1 Each independently represents an η-bonded cyclic anionic ligand selected from the group consisting of a cyclopentadienyl group, an indenyl group, a tetrahydroindenyl group, a fluorenyl group, a tetrahydrofluorenyl group, and an octahydrofluorenyl group, and the ligand may have 1 to 8 substituents, each independently being a substituent having up to 20 nonhydrogen atoms selected from the group consisting of a C1 to C20 hydrocarbon group, a halogen atom, a C1 to C12 halogen-substituted hydrocarbon group, a C1 to C12 aminohydrocarbyl group, a C1 to C12 hydrocarbyloxy group, a C1 to C12 dihydrocarbylamino group, a C1 to C12 hydrocarbylphosphono group, a silyl group, an aminosilyl group, a C1 to C12 hydrocarbyloxysilyl group, and a halosilyl group. M 1 This represents a transition metal selected from the transition metal group belonging to Group 4 of the periodic table with formal oxidation states of +2, +3, or +4, and which is bonded to at least one ligand L by an η5 linkage. W represents a divalent substituent having up to 50 non-hydrogen atoms, which is bonded to L and M with a valency of 1 each, thereby cooperating with L and M to form a metallocycle. X 1 Each of these independently represents an anionic σ-bond ligand having up to 60 non-hydrogen atoms, selected from the group consisting of a monovalent anionic σ-bond ligand, a divalent anionic σ-bond ligand that bonds to M in a divalent state, and a divalent anionic σ-bond ligand that bonds to L and M with a 1-valent state each. X 2 Each of these independently represents a neutral Lewis base coordinating compound having up to 40 non-hydrogen atoms. j is 1 or 2, however when j is 2, in some cases two ligands L are bonded to each other via a divalent group having up to 20 nonhydrogen atoms, the divalent group being selected from the group consisting of a C1-C20 hydrocarbadiyl group, a C1-C12 halohydrocarbadiyl group, a C1-C12 hydrocarbyleneoxy group, a C1-C12 hydrocarbyleneamino group, a silanediyl group, a halosilanediyl group, and a silyleneamino group, k is 0 or 1, and p is 0, 1 or 2, however X 1 If is a monovalent anionic σ-bond ligand, or a divalent anionic σ-bond ligand bonded to L and M, then p is an integer less than or equal to 1 the formal oxidation number of M, and X 1 If is a divalent anionic σ-bond ligand bonded only to M, then p is an integer less than or equal to (j+1) the formal oxidation number of M, and q is 0, 1, or 2. [ka] (In the formula, M 2 This represents a transition metal selected from the group consisting of titanium, zirconium, and hafnium, whose formal oxidation number is +2, +3, or +4. R 5 Each of these independently represents a substituent having 1 to 20 non-hydrogen atoms, selected from the group consisting of hydrogen atoms, hydrocarbon groups having 1 to 8 carbon atoms, silyl groups, germyl groups, cyano groups, halogen atoms, and composite groups thereof, provided that the substituent R 5 When is a hydrocarbon group having 1 to 8 carbon atoms, a silyl group, or a gelmyl group, there may be two adjacent substituents R 5 These two atoms bond to each other to form a divalent group, thereby the two adjacent substituents R 5 The bonds between the two carbon atoms of the cyclopentadienyl rings bonded to each of them cooperate to form rings, X 3represents, independently of each other, a substituent having 1 to 20 non-hydrogen atoms selected from the group consisting of a halide, a hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 18 carbon atoms, a hydrocarbylamino group having 1 to 18 carbon atoms, a silyl group, a hydrocarbylamide group having 1 to 18 carbon atoms, a hydrocarbylphosphide group having 1 to 18 carbon atoms, a hydrocarbylsulfide group having 1 to 18 carbon atoms, and a composite group thereof, provided that in some cases, two substituents X 3 act together to form a neutral conjugated diene or a divalent group having 4 to 30 carbon atoms, Y 1 represents -O-, -S-, -NR 6 -, or -PR 6 -, provided that R 6 represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, a hydrocarbyloxy group having 1 to 8 carbon atoms, a silyl group, a halogenated alkyl group having 1 to 8 carbon atoms, a halogenated aryl group having 6 to 20 carbon atoms, or a composite group thereof, Z 1 is SiR 6 2, CR 6 2, SiR 6 2SiR 6 2, CR 6 2CR 6 2, CR 6 =CR 6 , CR 6 2SiR 6 2 or GeR 6 2, provided that R 6 is as defined above, n is 1, 2 or 3.) (C-1): [L 2 -H] d+ [M 3 r Q s d- ···(Formula 5) (In the formula, [L 2 -H] d+ is a proton-donating Bronsted acid, and L 2 is a neutral Lewis base. Also, in the formula [M 3 r Q s d- is a compatible non-coordinating anion, and M​​3 Q is a metal or metalloid selected from groups 5 through 15 of the periodic table, and each Q is independently a hydride, dialkylamide group, halide, alkoxide group, allinoxide group, hydrocarbon group, or substituted hydrocarbon group with up to 20 carbon atoms. Furthermore, there is no more than one halide Q. Also, r is an integer from 1 to 7, s is an integer from 2 to 14, and d is an integer from 1 to 7, with sr = d. (C-2):-(M 4 R 7 t-2 -O) u -...(Formula 6) (In the formula, M 4 These are metals or metalloids from groups 13 to 15 of the periodic table, and R 7 Each of these is independently a hydrocarbon group or substituted hydrocarbon group having 1 to 12 carbon atoms, and t is a metal M 4 (This is the valence of , where u is an integer greater than or equal to 2.)

[15] The catalyst for olefin polymerization according to

[14] , wherein the inorganic solid particles [A] are magnesium chloride particles.

[16] A method for producing an olefin polymer, comprising the step of polymerizing an olefin using the olefin polymerization catalyst described in

[14] or

[15] . [Effects of the Invention]

[0009] The polyethylene powder of the present invention can provide, for example, a microporous membrane that is excellent in heat resistance, membrane uniformity, dimensional stability, and high heat resistance. [Modes for carrying out the invention]

[0010] The following describes in detail embodiments for carrying out the present invention (hereinafter also referred to as "this embodiment"). It should be noted that the present invention is not limited to this embodiment and can be appropriately modified and implemented within the scope of its gist.

[0011] [Polyethylene powder] The polyethylene powder of this embodiment has a viscosity-average molecular weight of 100,000 or more and 4,000,000 or less. The crystal thickness parameter obtained from measurements using differential scanning calorimeter (DSC) is between 5°C and 9°C. The polyethylene powder of this embodiment, having these characteristics, can provide a microporous membrane that is excellent in heat resistance, membrane uniformity, dimensional stability, and high heat resistance. Furthermore, the polyethylene powder of this embodiment is measured by a gel permeation chromatography (GPC) analyzer combining a differential refractometer and a viscosity detector, and the z-average contraction factor g z The value of (hereinafter referred to as "mean contraction factor g") z It is preferable that the value (also written as ) is between 0.600 and 1. The polyethylene powder of this embodiment, having these characteristics, can provide a microporous membrane that is even superior in heat resistance, membrane uniformity, dimensional stability, and high heat resistance. The crystal thickness parameter mentioned above is determined by the temperature at the peak top (Tm2) in the DSC curve of the second heating process obtained by the measurement shown in <Measurement Conditions> below. top ) and the temperature (Tm²) at the peak convergence point. end ) difference (Tm2 end -Tm2 top )(Hereafter, "Temperature difference in DSC curve (Tm2 end -Tm2 top It is also written as ")". <Measurement conditions> (1) Leave standing at 50°C for 1 minute. (2) Increase the temperature from 50°C to 180°C at a rate of 10°C / min (first heating process) (3) Let stand at 180°C for 5 minutes. (4) Cool from 180°C to 50°C at 10°C / min (5) Let stand at 50°C for 5 minutes. (6) Increase the temperature from 50°C to 180°C at a rate of 10°C / min (second heating process)

[0012] Furthermore, the polyethylene powder of this embodiment was measured using a differential scanning calorimeter (DSC) to obtain the DSC curve of the second heating process shown in the <Measurement Conditions> below, and the peak top temperature (Tm2 top) is between 135°C and 140°C, <Measurement conditions> (1) Leave standing at 50°C for 1 minute. (2) Increase the temperature from 50°C to 180°C at a rate of 10°C / min (first heating process) (3) Let stand at 180°C for 5 minutes. (4) Cool from 180°C to 50°C at 10°C / min (5) Let stand at 50°C for 5 minutes. (6) Increase the temperature from 50°C to 180°C at a rate of 10°C / min (second heating process) It is preferable that the crystal thickness parameter is between 6.7°C and 9.0°C.

[0013] The polyethylene powder of this embodiment, having these characteristics, can provide a microporous membrane that is even superior in heat resistance, membrane uniformity, dimensional stability, and high heat resistance.

[0014] The mechanism by which the polyethylene powder of this embodiment exhibits the effects described above is not clear, but the inventors have hypothesized the following. The DSC curve of the second heating process obtained by the measurement shown in <Measurement Conditions> above using a differential scanning calorimeter (DSC) shows the characteristics of the crystals generated during the recrystallization process of the polyethylene powder. Specifically, these crystal characteristics correspond to, for example, the characteristics of the crystals generated during the cooling process after melting and kneading polyethylene powder in the actual process of manufacturing a microporous film, and it is thought that the characteristics of the crystals generated here affect the physical properties of the microporous film. Furthermore, the temperature difference (Tm2) in the DSC curve... end -Tm2 topThe fact that the above range is present indicates that it contains high-melting-point polyethylene components, i.e., that thick crystalline regions exist. The process by which the crystalline regions grow thick is presumed to be that during the cooling process, low-mobility regions with one end constrained, such as long-chain branching, begin crystallization first, and then crystallization further progresses using these low-mobility regions as nuclei, locally increasing the thickness of the crystalline regions. Furthermore, it is presumed that the formation of such crystalline regions during the recrystallization process in the polyethylene powder of this embodiment is one of the reasons why it can provide a microporous film with excellent heat resistance, film uniformity, dimensional stability, and high heat resistance.

[0015] (viscosity average molecular weight) The polyethylene powder of this embodiment preferably has a viscosity-average molecular weight of 200,000 to 4,000,000, more preferably 250,000 to 3,000,000, and even more preferably 300,000 to 2,500,000. When the viscosity-average molecular weight of the polyethylene powder of this embodiment is above the lower limit, it tends to have sufficient mechanical strength when used to form a microporous membrane. Furthermore, when the viscosity-average molecular weight of the polyethylene powder of this embodiment is below the upper limit, it exhibits excellent moldability, suppresses thickness variations and the generation of unmelted material (uniformity) when used to form a microporous membrane, suppresses residual stress in the microporous membrane (low shrinkage rate), and is easily mixed with other polyethylene resins and tends not to segregate in the microporous membrane during blending. In this embodiment, the viscosity-average molecular weight of the polyethylene powder can be measured by the method described in the examples below.

[0016] (Temperature difference (Tm2) in the DSC curve end -Tm2 top )) The polyethylene powder of this embodiment exhibits a temperature difference (Tm2) in the DSC curve. end -Tm2 topThe peak top temperature (Tm2) is preferably 5°C to 9°C, preferably 6°C to 8.5°C, and more preferably 6.7°C to 8°C. Furthermore, the polyethylene powder of this embodiment is particularly important in that the peak top temperature (Tm2) is top If the temperature is between 135°C and 140°C, the temperature difference (Tm2) in the DSC curve will be considered. end -Tm2 top The temperature difference (Tm2) in the DSC curve is preferably 6.7°C or higher and 9.0°C or lower, more preferably 6.7°C or higher and 8.5°C or lower, and even more preferably 6.7°C or higher and 8.0°C or lower. The polyethylene powder of this embodiment has a temperature difference (Tm2) in the DSC curve. end -Tm2 top If the temperature difference (Tm2) in the DSC curve is greater than or equal to the lower limit, the high melting point component improves the heat resistance when a microporous film is formed, and by blending it with other polyethylene resins, the heat resistance can be further improved when a microporous film is formed. Furthermore, the polyethylene powder of this embodiment has a temperature difference (Tm2) in the DSC curve. end -Tm2 top When the above-mentioned upper limit is below the specified value, when used as a microporous membrane for secondary battery separators, the pores of the microporous membrane tend to close more easily when the battery overheats abnormally, and it also tends to be able to be stretched uniformly during the stretching process.

[0017] Temperature difference (Tm²) in the DSC curve end -Tm2 topThe method for obtaining polyethylene powder within the above range is not particularly limited, but for example, it is a method of producing a polymer containing a small amount of long-chain branching using a catalyst obtained by a special manufacturing method described later. Specifically, it is a method of production in which the main chain and side chains are controlled separately and the proportion of side chains is kept to a small amount. The method of controlling the main chain and side chains separately is not particularly limited, but for example, it is a method of using a catalyst containing two types of active species ((A) for macromonomer incorporation and (B) for macromonomer synthesis), changing the type of co-catalyst for each active species, pre-mixing the co-catalyst and active species and supporting them in two or more steps to form a multilayer structure on the surface of the support. There are no particular limitations on the method for keeping the proportion of side chains to a trace amount, but for example, one method is to control the ratio of the two types of active species ((A) for macromonomer incorporation / (B) for macromonomer synthesis) in the range of 1 to 1000, control the ratio of co-catalyst (C) to macromonomer incorporation active species (A) ((C) / (A)) in the range of 0.5 to 1.5, and control the ratio of co-catalyst (D) to macromonomer synthesis active species (B) ((D) / (B)) in the range of 1 to 60. In this embodiment, the temperature difference (Tm2) in the DSC curve of polyethylene powder is shown. end -Tm2 top ) can be measured by the method described in the examples below.

[0018] (Mean contraction factor g) z ) The polyethylene powder of this embodiment has an average shrinkage factor g z It is preferable that the average shrinkage factor g is 0.600 or more and 1 or less, more preferably 0.65 or more and 0.985 or less, and even more preferably 0.7 or more and 0.97 or less. The polyethylene powder of this embodiment has an average shrinkage factor g z When the average shrinkage factor g is above the lower limit, when a microporous membrane is formed, the residual stress in the microporous membrane is suppressed (low shrinkage rate), and the occurrence of entanglement due to branched chains is kept below a certain level, and crystallization tends to be promoted. Furthermore, the polyethylene powder of this embodiment has an average shrinkage factor g zWhen the value is below the aforementioned upper limit, high-melting-point crystals are more easily formed, and the strength during melting increases. As a result, when a microporous film is formed, the heat resistance is further improved, the stability during film formation is further improved, and film unevenness is suppressed. Blending it with other polyethylene resins tends to further improve the heat resistance and stretchability of the microporous film.

[0019] Mean contraction factor g z The method for obtaining polyethylene powder within the above range is not particularly limited, but for example, it is a method of producing a polymer containing a small amount of long-chain branching using a catalyst obtained by a special manufacturing method described later. Specifically, it is a method of production in which the main chain and side chains are controlled separately and the proportion of side chains is kept to a small amount. The method for controlling the main chain and side chains separately is not particularly limited, but for example, it is a method in which a catalyst containing two types of active species ((A) for macromonomer incorporation and (B) for macromonomer synthesis) is used, the type of co-catalyst is changed for each active species, and the co-catalyst and active species are pre-mixed and supported in two or more steps to form a multilayer structure on the surface of the support. There are no particular limitations on the method for keeping the proportion of side chains to a trace amount, but for example, one method is to control the ratio of the two types of active species ((A) for macromonomer incorporation / (B) for macromonomer synthesis) in the range of 1 to 1000, control the ratio of co-catalyst (C) to macromonomer incorporation active species (A) ((C) / (A)) in the range of 0.5 to 1.5, and control the ratio of co-catalyst (D) to macromonomer synthesis active species (B) ((D) / (B)) in the range of 1 to 60. In this embodiment, the average shrinkage factor g of polyethylene powder is used. z This can be measured by the method described in the examples below.

[0020] (Evaluation of stretchability) The polyethylene powder of this embodiment is preferably stretchable under the following conditions. (Stretching conditions) A 100mm x 100mm x 1mm thick gel sheet, consisting of 30% by mass polyethylene powder and 70% by mass liquid paraffin, is stretched 7 x 7 times at 115°C.

[0021] The polyethylene powder of this embodiment, when stretchable under the above conditions, tends to suppress uneven film thickness when used to form a microporous membrane. Furthermore, it tends to enable the production of microporous membranes with high productivity.

[0022] The method for obtaining polyethylene powder that can be stretched under the above conditions is not particularly limited, but for example, by appropriately adjusting the catalyst composition and polymerization conditions, ultra-high molecular weight components (molecular weight > 10) can be obtained. 7 One method is to keep the proportion of the above-mentioned factors below a certain level. In this embodiment, the stretchability under the above conditions can be specifically evaluated by the method described in the later-described examples.

[0023] (400cm -1 ~450cm -1 Absorption coefficient in The polyethylene powder of this embodiment measured 400 cm in terahertz measurements. -1 ~450cm -1 The absorption coefficient in is preferably 1.0 or more and 4.0 or less, more preferably 1.9 or more and 3.5 or less, and even more preferably 2.1 or more and 3.5 or less. The aforementioned 400cm -1 ~450cm -1 The attribution of the terahertz wave absorption peak in this region is unclear, but the terahertz waves are absorbed as vibrational energy of the polymer chains, and at 500 cm² -1 ~550cm -1 The absorption peak of terahertz waves at 400 cm corresponds to the vibration of the amorphous region of polyethylene. -1 ~450cm -1 The absorption peak in this region is presumed to correspond to vibrations originating from the long-chain branched structure present in the amorphous region.

[0024] The polyethylene powder of this embodiment measured 400 cm in terahertz measurements. -1 ~450cm -1When the absorption coefficient is within the aforementioned range, residual stress in the microporous membrane tends to be suppressed (low shrinkage rate). In addition, unevenness in film thickness when forming a microporous membrane tends to be suppressed.

[0025] In terahertz measurement, 400 cm -1 ~450cm -1 The method for obtaining polyethylene powder having an absorption coefficient within the above range is not particularly limited, but for example, one method is to make the incorporation of macromonomers uniform by appropriately adjusting the type of active species and co-catalyst and their combination. In this embodiment, 400 cm -1 ~450cm -1 The absorption coefficient in can be evaluated by the method described in the examples below.

[0026] ( 1 H-NMR measurement) The polyethylene powder of this embodiment is 1 In 1H-NMR measurements, it is preferable that no peaks are present in the regions shown below. (1) 4.8 ppm ~ 5.0 ppm (2) 5.6 ppm ~ 6.0 ppm (1) and (2) are regions where signals corresponding to terminal double bonds are detected, and the absence of peaks in these regions means that no macromonomers remain in the polyethylene powder.

[0027] The polyethylene powder of this embodiment is 1 In H-NMR measurements, the absence of peaks in the region shown above indicates that when a microporous film is formed, it can be stretched uniformly, which tends to suppress variations in film thickness. Furthermore, residual stress in the microporous film is further reduced (low shrinkage rate), and when blended with other polyethylene resins, a uniform microporous film tends to be obtained.

[0028] 1In 1H-NMR measurements, there are no particular limitations on the method for obtaining polyethylene powder in which no peaks exist in the region shown above. For example, methods include supporting an active species capable of incorporating macromonomers on the outermost surface of the catalyst, or appropriately adjusting the catalyst raw material composition and comonomer amount to prevent the retention of terminal double bonds. In this embodiment, the polyethylene powder 1 The H-NMR peak can be measured by the method described in the examples below.

[0029] (aluminum content) The polyethylene powder of this embodiment preferably has an aluminum content of 0 ppm to 50 ppm, more preferably 0 ppm to 30 ppm, and even more preferably 0 ppm to 15 ppm. When the aluminum content of the polyethylene powder of this embodiment is within the above range, high-melting-point crystals tend to be easily formed, and when formed into a microporous film, it tends to be of high quality. Furthermore, it can suppress clogging of filters during the molding process, leading to improved productivity. In this embodiment, the aluminum content in the polyethylene powder can be measured by the method described in the examples below.

[0030] (Silicon content) The polyethylene powder of this embodiment preferably has a silicon content of 0 ppm to 30 ppm, more preferably 0 ppm to 10 ppm, and even more preferably 0 ppm to 2 ppm. When the silicon content of the polyethylene powder of this embodiment is within the above range, high melting point crystals tend to be easily formed, and when formed into a microporous membrane, it tends to be of high quality. Furthermore, it can suppress clogging of filters during the molding process, leading to improved productivity. In this embodiment, the silicon content in the polyethylene powder can be measured by the method described in the examples below.

[0031] (Temperature of the peak top in the DSC curve during the second heating process) In differential scanning calorimeter (DSC) measurements, the polyethylene powder in this embodiment shows that the peak top temperature (hereinafter referred to as "Tm2") in the DSC curve during the second heating process is measured. top The temperature (also written as ") is preferably 130°C to 140°C, more preferably 133°C to 140°C, and even more preferably 135°C to 140°C. Furthermore, in the case of the polyethylene powder of this embodiment, in particular when the crystal thickness parameter is 6.7°C to 9.0°C, Tm2 top However, it is preferable that the temperature be between 135°C and 140°C, more preferably between 136°C and 140°C, and even more preferably between 137°C and 140°C. The polyethylene powder of this embodiment is Tm2 top When the range is within the aforementioned range, the heat resistance of the microporous membrane can be improved, and because heat can be applied during the heat setting process, residual stress in the microporous membrane can be suppressed, and furthermore, the air permeability of the microporous membrane tends to be increased. Tm2 top The method for obtaining polyethylene powder within the aforementioned range is not particularly limited, but examples include adjusting the catalyst raw material composition and the amount of comonomer. In this embodiment, Tm2 top This can be measured by the method described in the examples below.

[0032] (density) The polyethylene powder of this embodiment has a density of 920 kg / m³. 3 More than 960kg / m 3 Preferably, it is 930 kg / m 3 More than 955kg / m 3 It is more preferable that the following conditions are met: 935 kg / m 3 More than 950kg / m 3 The following is even more preferable: When the polyethylene powder of this embodiment has a density within the above range, it tends to have excellent air permeability and heat resistance when used as a microporous membrane. In this embodiment, the density of the polyethylene powder can be measured by the method described in the examples below.

[0033] (Method for producing catalysts for olefin polymerization) The method for producing the olefin polymerization catalyst of this embodiment comprises a first supporting reaction step in which inorganic solid particles [A] are reacted with a transition metal compound [B-1] and / or a transition metal compound component [B-2] and an activator [C] and / or an organometallic compound component [D], The process includes a second supporting reaction step in which the particles obtained in the first supporting reaction step are reacted with a transition metal compound component [B-1] and / or a transition metal compound component [B-2] and an activator [C] and / or an organometallic compound component [D]. The transition metal compound [B-1] is a compound represented by the following (Formula 3), the transition metal compound [B-2] is a compound represented by the following (Formula 4), the activator [C] is a compound represented by the following (Formula 5) or (Formula 6), the organometallic compound component [D] is a compound containing at least one metal selected from the group consisting of Groups 1, 2, 12 and 13 of the periodic table, and the inorganic solid particles [A] are porous polymer materials or inorganic solid particles containing at least one element selected from the group consisting of Groups 2 to 4, 13 and 14 of the periodic table. The following conditions 1 and / or 2 are met. <Condition 1> The first supporting reaction step includes a pre-mixing step in which a transition metal compound [B-1] and / or a transition metal compound component [B-2] are reacted with an activator [C] and / or an organometallic compound component [D], and a step in which the mixture obtained in the pre-mixing step is reacted with inorganic solid particles [A]. <Condition 2> In the first supporting reaction step, the molar ratio (([C]+[D]) / [B]) of the molar amount of the activator [C] and organometallic compound component [D] to the molar amount [B] of the transition metal compound component [B-1] and / or the transition metal compound component [B-2] is 1 or more and 60 or less. L 1 j Wk M 1 X 1 p X 2 q ...(Formula 3) (In the formula, L 1 Each independently represents an η-bonded cyclic anionic ligand selected from the group consisting of a cyclopentadienyl group, an indenyl group, a tetrahydroindenyl group, a fluorenyl group, a tetrahydrofluorenyl group, and an octahydrofluorenyl group, and the ligand may have 1 to 8 substituents, each independently being a substituent having up to 20 nonhydrogen atoms selected from the group consisting of a C1 to C20 hydrocarbon group, a halogen atom, a C1 to C12 halogen-substituted hydrocarbon group, a C1 to C12 aminohydrocarbyl group, a C1 to C12 hydrocarbyloxy group, a C1 to C12 dihydrocarbylamino group, a C1 to C12 hydrocarbylphosphono group, a silyl group, an aminosilyl group, a C1 to C12 hydrocarbyloxysilyl group, and a halosilyl group. M 1 This represents a transition metal selected from the transition metal group belonging to Group 4 of the periodic table with formal oxidation states of +2, +3, or +4, and which is bonded to at least one ligand L by an η5 linkage. W represents a divalent substituent having up to 50 non-hydrogen atoms, which is bonded to L and M with a valency of 1 each, thereby cooperating with L and M to form a metallocycle. X 1 Each of these independently represents an anionic σ-bond ligand having up to 60 non-hydrogen atoms, selected from the group consisting of a monovalent anionic σ-bond ligand, a divalent anionic σ-bond ligand that bonds to M in a divalent state, and a divalent anionic σ-bond ligand that bonds to L and M with a 1-valent state each. X 2 Each of these independently represents a neutral Lewis base coordinating compound having up to 40 non-hydrogen atoms. j is 1 or 2, however when j is 2, in some cases two ligands L are bonded to each other via a divalent group having up to 20 nonhydrogen atoms, the divalent group being selected from the group consisting of a C1-C20 hydrocarbadiyl group, a C1-C12 halohydrocarbadiyl group, a C1-C12 hydrocarbyleneoxy group, a C1-C12 hydrocarbyleneamino group, a silanediyl group, a halosilanediyl group, and a silyleneamino group, k is 0 or 1, and p is 0, 1 or 2, however X 1 If is a monovalent anionic σ-bond ligand, or a divalent anionic σ-bond ligand bonded to L and M, then p is an integer less than or equal to 1 the formal oxidation number of M, and X 1 If is a divalent anionic σ-bond ligand bonded only to M, then p is an integer less than or equal to (j+1) the formal oxidation number of M, and q is 0, 1, or 2. [ka] (In the formula, M 2 This represents a transition metal selected from the group consisting of titanium, zirconium, and hafnium, whose formal oxidation number is +2, +3, or +4. R 5 Each of these independently represents a substituent having 1 to 20 non-hydrogen atoms, selected from the group consisting of hydrogen atoms, hydrocarbon groups having 1 to 8 carbon atoms, silyl groups, germyl groups, cyano groups, halogen atoms, and composite groups thereof, provided that the substituent R 5 When is a hydrocarbon group having 1 to 8 carbon atoms, a silyl group, or a gelmyl group, there may be two adjacent substituents R 5 These two atoms bond to each other to form a divalent group, thereby the two adjacent substituents R 5 The bonds between the two carbon atoms of the cyclopentadienyl rings bonded to each of them cooperate to form rings, X 3Each of these independently represents a substituent having 1 to 20 nonhydrogen atoms, selected from the group consisting of halides, hydrocarbon groups having 1 to 20 carbon atoms, hydrocarbyloxy groups having 1 to 18 carbon atoms, hydrocarbylamino groups having 1 to 18 carbon atoms, silyl groups, hydrocarbylamide groups having 1 to 18 carbon atoms, hydrocarbylphosphine groups having 1 to 18 carbon atoms, hydrocarbyl sulfide groups having 1 to 18 carbon atoms, and composite groups thereof, provided that there may be two substituents X. 3 These groups cooperate to form a neutral conjugated diene or divalent group with 4 to 30 carbon atoms. Y 1 -O-, -S-, -NR 6 - or -PR 6 - represents, however, R 6 This represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, a hydrocarbyloxy group having 1 to 8 carbon atoms, a silyl group, an alkyl halide having 1 to 8 carbon atoms, an aryl halide having 6 to 20 carbon atoms, or a composite group thereof. Z 1 is SiR 6 2. CR 6 2. SiR 6 2SiR 6 2. CR 6 2CR 6 2. CR 6 =CR 6 , CR 6 2SiR 6 2 or GeR 6 Represents 2, however R 6 As defined above, n is 1, 2, or 3. (C-1):[L 2 -H] d+ [M 3 r Q s ] d- ...(Formula 5) (In the formula, [L 2 -H] d+ It is a proton-donating Brønsted acid, L 2 [M is a neutral Lewis base. Also, in the formula, [M 3 r Q s ] d- M is a compatible non-coordinating anion.3 Q is a metal or metalloid selected from groups 5 through 15 of the periodic table, and each Q is independently a hydride, dialkylamide group, halide, alkoxide group, allinoxide group, hydrocarbon group, or substituted hydrocarbon group with up to 20 carbon atoms. Furthermore, there is no more than one halide Q. Also, r is an integer from 1 to 7, s is an integer from 2 to 14, and d is an integer from 1 to 7, with sr = d. (C-2):-(M 4 R 7 t-2 -O) u -...(Formula 6) (In the formula, M 4 These are metals or metalloids from groups 13 to 15 of the periodic table, and R 7 Each of these is independently a hydrocarbon group or substituted hydrocarbon group having 1 to 12 carbon atoms, and t is a metal M 4 (This is the valence of , where u is an integer greater than or equal to 2.) The transition metal compound used in the first loading reaction step is preferably [B-1], and the transition metal compound used in the second loading reaction step is preferably [B-2]. Furthermore, in the second loading reaction step, the molar ratio (([C]+[D]) / [B]) of the molar amount of the activator [C] and organometallic compound component [D] ([C]+[D]) to the molar amount [B] of the transition metal compound component [B-1] and / or the transition metal compound component [B-2] is preferably 0.5 or more and 1.5 or less, and more preferably 0.9 or more and 1.1 or less. Moreover, the molar ratio ([B2] / [B1]) of the transition metal compound component ([B1]) used in the second loading reaction step to the transition metal compound component ([B2]) used in the first loading reaction step is preferably 1 or more and 1000 or less, and more preferably 5 or more and 100 or less. By including the first and second support reaction steps, two layers consisting of a mixture of a transition metal compound and an activator can be formed on the surface of the inorganic solid particles [A]. This two-layer structure allows macromonomers generated in the first layer to be incorporated into the transition metal compound in the second layer, thus facilitating the control of long-chain branching in the production of olefin polymers. Furthermore, by controlling the molar ratios ([C]+[D]) / [B]) and ([B2] / [B1])), the amount of long-chain branching in the production of olefin polymers can be reduced to a trace amount. The method for producing the olefin polymerization catalyst of this embodiment satisfies the following conditions 1 and / or 2. <Condition 1> The first supporting reaction step includes a pre-mixing step in which a transition metal compound [B-1] and / or a transition metal compound component [B-2] are reacted with an activator [C] and / or an organometallic compound component [D], and a step in which the mixture obtained in the pre-mixing step is reacted with inorganic solid particles [A]. By satisfying <Condition 1>, it is possible to form a layer on the surface of inorganic solid particles [A] in which the transition metal compound and activator are uniformly mixed. By forming a uniform mixed layer, the incorporation of macromonomers becomes uniform, making it possible to synthesize olefin polymers with less segregation of long-chain branching. <Condition 2> In the first supporting reaction step, the molar ratio (([C]+[D]) / [B]) of the molar amounts of the activator [C] and organometallic compound component [D] ([C]+[D]) to the molar amount [B] of the transition metal compound component [B-1] and / or the transition metal compound component [B-2] is 1 or more and 60 or less, and preferably 1 or more and 30 or less. By satisfying condition 2, the amount of macromonomers produced can be suppressed, which tends to allow for a very small amount of long-chain branching in the production of olefin polymers. The method for producing the catalyst for olefin polymerization according to this embodiment allows for the synthesis of olefin polymers containing trace amounts of long-chain branching by satisfying the above-mentioned process conditions. Furthermore, it facilitates the control of the amount and length of long-chain branching during the production of olefin polymers.

[0034] (Inorganic solid particles used in the method for producing catalysts for olefin polymerization [A]) In the method for producing the olefin polymerization catalyst of this embodiment, it is preferable to use magnesium chloride particles as the inorganic solid particles [A]. In the method for producing the olefin polymerization catalyst of this embodiment, when magnesium chloride particles are used as inorganic solid particles [A], the catalyst particles tend to crack more easily during polymerization, and it is possible to produce an olefin polymer with less metal residue.

[0035] (Catalyst for olefin polymerization) The catalyst for olefin polymerization in this embodiment comprises inorganic solid particles [A], a transition metal compound component [B-1] and / or a transition metal compound component [B-2], and an activator [C] and / or an organometallic compound component [D]. The transition metal compound [B-1] is a compound represented by (Formula 3) above, the transition metal compound [B-2] is a compound represented by (Formula 4) above, the activator [C] is a compound represented by (Formula 5) or (Formula 6) above, the organometallic compound component [D] is a compound containing at least one metal selected from the group consisting of Groups 1, 2, 12 and 13 of the periodic table, and the inorganic solid particles [A] are porous polymer materials or inorganic solid particles containing at least one element selected from the group consisting of Groups 2 to 4, 13 and 14 of the periodic table. The content (mol) of central metal M in the transition metal compound component [B-1] and / or the transition metal compound component [B-2] is 20 μmol or more and 1000 μmol or less, and the molar ratio (Al / M) of the content (mol) of central metal M to the content (mol) of Al is 1 or more and 30 or less. Preferably, the content (mol) of central metal M is 20 μmol or more and 250 μmol or less, and preferably the molar ratio (Al / M) is 1 or more and 10 or less. The catalyst for olefin polymerization in this embodiment contains each of the above components, and if the content (mol) of the central metal M and the molar ratio (Al / M) of the central metal M content (mol) to the Al content (mol) are within the above range, it becomes easier to control the amount and length of long-chain branching in the olefin polymer obtained by polymerization, and it is also possible to suppress the amount of long-chain branching in the olefin polymer to a minute amount. In this embodiment, the content (mol) of the central metal M in the catalyst component and the molar ratio (Al / M) of the content (mol) of the central metal M to the content (mol) of Al can be measured by the method described in the examples below.

[0036] (Inorganic solid particles contained in olefin polymerization catalysts [A]) In this embodiment, the catalyst for olefin polymerization preferably has magnesium chloride particles as the inorganic solid particles [A]. In this embodiment, when the inorganic solid particles [A] of the olefin polymerization catalyst are magnesium chloride particles, the catalyst particles tend to crack more easily during polymerization, and it is possible to produce olefin polymers with less metal residue.

[0037] In this embodiment, the inorganic solid particles [A], transition metal compound [B-1], transition metal compound component [B-2], activator [C], and organometallic compound component [D] in the olefin polymerization catalyst can be appropriately replaced with those described in the [Method for Producing Polyethylene Powder] below. Furthermore, the conditions in the method for producing the olefin polymerization catalyst in this embodiment can be appropriately replaced with those described in the [Method for Producing Polyethylene Powder] below.

[0038] The method for producing the olefin polymer of this embodiment includes a step of polymerizing an olefin using the above-mentioned catalyst for olefin polymerization.

[0039] [Method for manufacturing polyethylene powder] An example of a method for producing polyethylene powder according to this embodiment is described below.

[0040] (Catalyst component) The polyethylene powder of this embodiment can be produced, for example, by polymerizing ethylene or ethylene with other comonomers using a predetermined catalyst component.

[0041] The catalyst components used in the production of the ethylene-based polymer constituting the polyethylene powder of this embodiment are not particularly limited, but preferably they consist of, for example, inorganic solid particles [A], a transition metal compound component [B-1], a transition metal compound component [B-2], and an activator [C] and / or an organometallic compound component [D].

[0042] In this embodiment, the inorganic solid particles [A] are not particularly limited, but examples include porous polymer materials (where the matrix includes, for example, polyolefins and their modified products such as polyethylene, polypropylene, polystyrene, ethylene-propylene copolymer, ethylene-vinyl ester copolymer, styrene-divinylbenzene copolymer, and partial or complete saponified ethylene-vinyl ester copolymers, thermoplastic resins such as polyamide, polycarbonate, and polyester, thermosetting resins such as phenolic resin, epoxy resin, urea resin, and melamine resin), inorganic solid particles containing at least one element selected from the group consisting of groups 2 to 4, 13, and 14 of the periodic table (for example, silica, alumina, magnesia, magnesium chloride, zirconia, titania, boron oxide, calcium oxide, zinc oxide, barium oxide, vanadium pentoxide, chromium oxide, thorium oxide, or mixtures thereof or composite oxides thereof). The silica-containing composite oxide is not particularly limited, but examples include silica-magnesia, silica-alumina, and other composite oxides of silica and an element selected from Group 2 or Group 13 of the periodic table. In this embodiment, the inorganic solid particles [A] are preferably selected from silica, alumina, and composite oxides of silica and an element selected from Group 2 or Group 13 of the periodic table.

[0043] There are no particular restrictions on the shape of the silica product used as inorganic solid particles [A], and the silica may take any shape, such as granular, spherical, aggregated, or fumean. Preferred examples of commercially available silica products, though not particularly limited, include SD3216.30, SP-9-10046, Davison Syloid™ 245, Davison 948 or Davison 952 [all manufactured by Grace Davison Corporation (a subsidiary of WR Davison Corporation (USA))], Aerosil 812 [manufactured by Dexa AG (Germany)], ES70X [manufactured by Crossfield Corporation (USA)], P-6, P-10, Q-6 [manufactured by Fuji Silicia Corporation (Japan)].

[0044] There are no particular restrictions on the properties of magnesium chloride used as inorganic solid particles [A]. Furthermore, a preferred method for producing magnesium chloride involves reacting an organomagnesium compound (A-1) soluble in an inert hydrocarbon solvent represented by the following formula (Formula 1) with a chlorinating agent (A-2) represented by the following formula (Formula 2). (A-1):(M 1 ) γ (Mg) δ (R 1 ) e (R 2 ) f (OR 3 ) g ...(Formula 1) (In formula 1, M 1 R is a metal atom belonging to one of the groups consisting of Groups 12, 13, and 14 of the periodic table, 1 , R 2 and R 3 Each of these is a hydrocarbon group having 2 to 20 carbon atoms, and γ, δ, e, f, and g are real numbers satisfying the following relationship. 0≦γ, 0<δ, 0≦e, 0≦f, 0≦g, 0 <e+f、0≦g / (γ+δ)≦2、kγ+2δ=e+f+g(ここで、kはM 1 This represents the valence of an atom. (A-2):H h SiCl i R 4 (4-(h+i)) ...(Formula 2) (In formula 2, R 4 is a hydrocarbon group having 1 to 12 carbon atoms, and h and i are real numbers satisfying the following relationship: 0 <h、0<i、0<h+i≦4)

[0045] First, let's discuss organomagnesium compounds (A-1). Organomagnesium compounds (A-1) are presented as complex compounds of organomagnesium soluble in inert hydrocarbon solvents, and encompass all dihydrocarbyl magnesium compounds and complexes of these compounds with other metal compounds.

[0046] The above-mentioned relation kγ+2δ=e+f+g, where the symbols γ, δ, e, f, and g are (Equation 1), represents the stoichiometric relationship between the valence of a metal atom and its substituent.

[0047] In the above (Equation 1), R 1 , R 2 The hydrocarbon group represented is not particularly limited, but for example, each can be an alkyl group, a cycloalkyl group, or an aryl group independently. More specifically, although not particularly limited, examples include methyl, ethyl, propyl, butyl, propyl, hexyl, octyl, decyl, cyclohexyl, and phenyl groups. Among these, R 1 and R 2 Preferably, each of these is an alkyl group.

[0048] If γ > 0, the metal atom M 1 As such, metal atoms belonging to any of the groups consisting of Groups 12, 13, and 14 of the periodic table can be used, and more specifically, although not particularly limited, examples include zinc, boron, and aluminum. Aluminum and zinc are particularly preferred.

[0049] metal atom M 1 The ratio of magnesium to γ ​​(δ / γ) is not particularly limited, but is preferably 0.1 to 30, and more preferably 0.5 to 10.

[0050] Also, when using a predetermined organomagnesium compound with γ = 0 as (A-1), for example, when R 1 is a 1-methylpropyl group or the like, it is soluble in an inert hydrocarbon solvent, and such a compound also gives favorable results in the production of the polyethylene powder of this embodiment.

[0051] In the above (Formula 1), when γ = 0, the hydrocarbon groups R 1 and R 2 are preferably any one of the following three groups (1), (2), and (3). Group (1): At least one of R 1 and R 2 is a secondary or tertiary alkyl group having 4 to 6 carbon atoms. Preferably, both R 1 and R 2 have 4 to 6 carbon atoms, and at least one of them is a secondary or tertiary alkyl group. Group (2): R 1 and R 2 are alkyl groups having different carbon numbers. Preferably, R 1 is an alkyl group having 2 or 3 carbon atoms, and R 2 is an alkyl group having 4 or more carbon atoms. Group (3):

[0052] At least one of R 1 and R 2 is a hydrocarbon group having 6 or more carbon atoms. Preferably, it is an alkyl group in which the sum of the carbon numbers contained in R 1 and R 2 is 12 or more.

[0053] Hereinafter, in the above (Formula 1), when γ = 0, the hydrocarbon groups R 1 and R 2 are specifically shown. In the group (1), the secondary or tertiary alkyl group having 4 to 6 carbon atoms is not particularly limited. For example, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, 2-methylbutyl, 2-ethylpropyl, 2,2-dimethylpropyl, 2-methylpentyl, 2-ethylbutyl, 2,2-dimethylbutyl, 2-methyl-2-ethylpropyl group and the like can be mentioned. Particularly, the 1-methylpropyl group is preferred.

[0054] In addition, in the group (2), the alkyl group having 2 or 3 carbon atoms is not particularly limited. For example, ethyl, 1-methylethyl, propyl group and the like can be mentioned. Particularly, the ethyl group is preferred. In addition, the alkyl group having 4 or more carbon atoms is not particularly limited. For example, butyl, pentyl, hexyl, heptyl, octyl group and the like can be mentioned. Particularly, the butyl and hexyl groups are preferred.

[0055] Furthermore, in the group (3), the hydrocarbon group having 6 or more carbon atoms is not particularly limited. For example, hexyl, heptyl, octyl, nonyl, decyl, phenyl, 2-naphthyl group and the like can be mentioned. Among the hydrocarbon groups, an alkyl group is preferred, and among the alkyl groups, the hexyl and octyl groups are more preferred.

[0056] Generally, as the number of carbon atoms contained in the alkyl group increases, it tends to be more soluble in an inert hydrocarbon solvent and the viscosity of the solution tends to increase. Therefore, in the above (Formula 1), as the hydrocarbon group R 1 , R 2 , it is preferably to use a moderately long-chain alkyl group for handling. The above organic magnesium compound (A-1) is used as an inert hydrocarbon solution, and even if trace amounts of Lewis basic compounds such as ether, ester, amine, etc. are contained or remain in the solution, it can be used without any problem.

[0057] Next, the alkoxy group (OR 3 ) in the (Formula 1) of the organic magnesium compound (A-1) will be described.

[0058] R 3 The hydrocarbon group represented is preferably an alkyl group or aryl group having 1 to 12 carbon atoms, and more preferably an alkyl group or aryl group having 3 to 10 carbon atoms.

[0059] R 3 Examples of these groups, though not particularly limited, include methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 1,1-dimethylethyl, pentyl, hexyl, 2-methylpentyl, 2-ethylbutyl, 2-ethylpentyl, 2-ethylhexyl, 2-ethyl-4-methylpentyl, 2-propylheptyl, 2-ethyl-5-methyloctyl, octyl, nonyl, decyl, phenyl, and naphthyl groups. In particular, butyl, 1-methylpropyl, 2-methylpentyl, and 2-ethylhexyl groups are more preferred.

[0060] The method for synthesizing organomagnesium compounds (A-1) is not particularly limited, but for example, formula: R 1 MgX 1 and formula:R 1 2Mg(R 1 As mentioned above, X 1 is a halogen atom. ) Any organomagnesium compound belonging to the group consisting of and formula: M 1 R 2 k and formula: M 1 R 2 (k-1) H(M 1 , R 2 And k are as described above.) Any organometallic compound belonging to the group consisting of ) is reacted in an inert hydrocarbon solvent at a temperature of 25°C to 150°C, and if necessary, R is then reacted. 2 (R 2 As mentioned above, an alcohol having a hydrocarbon group represented by ) or R soluble in an inert hydrocarbon solvent 2 One method of synthesis involves reacting an alkoxymagnesium compound having a hydrocarbon group represented by and / or an alkoxyaluminum compound with it.

[0061] In the method described above, when reacting an organomagnesium compound soluble in an inert hydrocarbon solvent with an alcohol, there are no particular restrictions on the order of the reaction. Any of the following methods can be used: adding the alcohol to the organomagnesium compound, adding the organomagnesium compound to the alcohol, or adding both simultaneously.

[0062] The reaction ratio between an organomagnesium compound soluble in an inert hydrocarbon solvent and an alcohol is not particularly limited, but the molar composition ratio of alkoxy groups to total metal atoms in the resulting alkoxy group-containing organomagnesium compound, g / (γ+δ), is preferably 0 ≤ g / (γ+δ) ≤ 2 and 0 ≤ g / (γ+δ) < 1.

[0063] Next, we will explain the chlorinating agent (A-2). The chlorinating agent (A-2) is a silicon chloride compound represented by (Formula 2), in which at least one compound has a Si-H bond. (A-2):H h SiCl i R 4 (4-(h+i)) ...(Formula 2) (In formula 2, R 4 is a hydrocarbon group having 1 to 12 carbon atoms, and h and i are real numbers satisfying the following relationship: 0 <h、0<i、0<h+i≦4)

[0064] In the above (Equation 2), R 4 The hydrocarbon group represented is not particularly limited, but examples include aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. Specifically, examples include methyl, ethyl, propyl, 1-methylethyl, butyl, pentyl, hexyl, octyl, decyl, cyclohexyl, and phenyl groups.

[0065] In particular, alkyl groups having 1 to 10 carbon atoms are preferred, and alkyl groups having 1 to 3 carbon atoms, such as methyl, ethyl, propyl, and 1-methylethyl groups, are more preferred. Furthermore, h and i are numbers greater than 0 that satisfy the relationship h + i ≤ 4, and it is preferable that i is between 2 and 3.

[0066] The chlorinating agent (A-2) is not particularly limited, but examples include HSiCl3, HSiCl2CH3, HSiCl2C2H5, HSiCl2(C3H7), HSiCl2(2-C3H7), HSiCl2(C4H9), HSiCl2(C6H5), HSiCl2(4-Cl-C6H4), HSiCl2(CH=CH2), HSiCl2(CH2C6H5), and HSiCl2(1-C 10 Examples include H7), HSiCl2(CH2CH=CH2), H2SiCl(CH3), H2SiCl(C2H5), HSiCl(CH3)2, HSiCl(C2H5)2, HSiCl(CH3)(2-C3H7), HSiCl(CH3)(C6H5), HSiCl(C6H5)2, etc.

[0067] As the chlorinating agent (A-2), a silicon chloride compound consisting of these compounds or a mixture of two or more compounds selected from these compounds is used.

[0068] In particular, HSiCl3, HSiCl2CH3, HSiCl(CH3)2, and HSiCl2(C3H7) are preferred, and HSiCl3 and HSiCl2CH3 are more preferred.

[0069] Next, we will explain the reaction between the organomagnesium compound (A-1) and the chlorinating agent (A-2). In the reaction, it is preferable to dilute the chlorinating agent (A-2) beforehand with an inert hydrocarbon solvent, a chlorinated hydrocarbon such as 1,2-dichloroethane, o-dichlorobenzene, or dichloromethane, an ether-based solvent such as diethyl ether or tetrahydrofuran, or a mixture thereof. Among these, the use of an inert hydrocarbon solvent is more preferable in terms of catalyst performance.

[0070] The reaction ratio of the organomagnesium compound (A-1) and the chlorinating agent (A-2) is not particularly limited, but the number of moles of silicon atoms contained in the chlorinating agent (A-2) per 1 mol of magnesium atoms contained in the organomagnesium compound (A-1) is preferably 0.01 mol or more and 100 mol or less, and more preferably 0.1 mol or more and 10 mol or less.

[0071] There is no particular limitation on the reaction method of the organomagnesium compound (A-1) and the chlorinating agent (A-2). Any of the methods of simultaneous addition in which the organomagnesium compound (A-1) and the chlorinating agent (A-2) are simultaneously introduced into the reactor and reacted, the method in which the chlorinating agent (A-2) is previously charged into the reactor and then the organomagnesium compound (A-1) is introduced into the reactor, or the method in which the organomagnesium compound (A-1) is previously charged into the reactor and then the chlorinating agent (A-2) is introduced into the reactor can be used. In particular, the method in which the chlorinating agent (A-2) is previously charged into the reactor and then the organomagnesium compound (A-1) is introduced into the reactor is preferred.

[0072] The reaction temperature of the organomagnesium compound (A-1) and the chlorinating agent (A-2) is not particularly limited, but it is preferably 25°C or higher and 150°C or lower, more preferably 30°C or higher and 120°C or lower, and even more preferably 40°C or higher and 100°C or lower.

[0073] In the method of simultaneous addition in which the organomagnesium compound (A-1) and the chlorinating agent (A-2) are simultaneously introduced into the reactor and reacted, it is preferable to adjust the temperature of the reactor to a predetermined temperature in advance and adjust the temperature in the reactor to the predetermined temperature while performing the simultaneous addition.

[0074] In the method in which the chlorinating agent (A-2) is previously charged into the reactor and then the organomagnesium compound (A-1) is introduced into the reactor, it is preferable to adjust the temperature of the reactor charged with the chlorinating agent (A-2) to a predetermined temperature and adjust the temperature in the reactor to the predetermined temperature while introducing the organomagnesium compound (A-1) into the reactor.

[0075] In a method in which an organomagnesium compound (A-1) is initially charged into the reactor, followed by the introduction of a chlorinating agent (A-2), it is preferable to adjust the temperature of the reactor containing the organomagnesium compound (A-1) to a predetermined temperature, and then adjust the temperature inside the reactor to the predetermined temperature while introducing the chlorinating agent (A-2) into the reactor.

[0076] The magnesium chloride obtained by the above reaction is preferably separated by filtration or decantation, and then thoroughly washed with an inert hydrocarbon solvent to remove unreacted substances or by-products.

[0077] Next, the transition metal compound component [B-1] used in this embodiment will be described. Examples of the transition metal compound component [B-1] used in this embodiment are not particularly limited, but for example, the compound represented by the following (Equation 3) can be cited. L 1 j W k M 1 X 1 p X 2 q ...(Formula 3) (In the formula, L 1 Each independently represents an η-bonded cyclic anionic ligand selected from the group consisting of a cyclopentadienyl group, an indenyl group, a tetrahydroindenyl group, a fluorenyl group, a tetrahydrofluorenyl group, and an octahydrofluorenyl group, and the ligand may have 1 to 8 substituents, each independently being a substituent having up to 20 nonhydrogen atoms selected from the group consisting of a C1 to C20 hydrocarbon group, a halogen atom, a C1 to C12 halogen-substituted hydrocarbon group, a C1 to C12 aminohydrocarbyl group, a C1 to C12 hydrocarbyloxy group, a C1 to C12 dihydrocarbylamino group, a C1 to C12 hydrocarbylphosphono group, a silyl group, an aminosilyl group, a C1 to C12 hydrocarbyloxysilyl group, and a halosilyl group. M 1This represents a transition metal selected from the transition metal group belonging to Group 4 of the periodic table with formal oxidation states of +2, +3, or +4, and which is bonded to at least one ligand L by an η5 linkage. W represents a divalent substituent having up to 50 non-hydrogen atoms, which is bonded to L and M with a valency of 1 each, thereby cooperating with L and M to form a metallocycle. X 1 Each of these independently represents an anionic σ-bond ligand having up to 60 non-hydrogen atoms, selected from the group consisting of a monovalent anionic σ-bond ligand, a divalent anionic σ-bond ligand that bonds to M in a divalent state, and a divalent anionic σ-bond ligand that bonds to L and M with a 1-valent state each. X 2 Each of these independently represents a neutral Lewis base coordinating compound having up to 40 non-hydrogen atoms. j is 1 or 2, however when j is 2, in some cases two ligands L are bonded to each other via a divalent group having up to 20 nonhydrogen atoms, the divalent group being selected from the group consisting of a C1-C20 hydrocarbadiyl group, a C1-C12 halohydrocarbadiyl group, a C1-C12 hydrocarbyleneoxy group, a C1-C12 hydrocarbyleneamino group, a silanediyl group, a halosilanediyl group, and a silyleneamino group, k is 0 or 1, and p is 0, 1 or 2, however X 1 If is a monovalent anionic σ-bond ligand, or a divalent anionic σ-bond ligand bonded to L and M, then p is an integer less than or equal to 1 the formal oxidation number of M, and X 1 If is a divalent anionic σ-bond ligand bonded only to M, then p is an integer less than or equal to (j+1) the formal oxidation number of M, and q is 0, 1, or 2.

[0078] Ligand X in the compound (Equation 3) above 1Examples of these include, but are not limited to, hydrides, halides, hydrocarbon groups having 1 to 60 carbon atoms, hydrocarbyloxy groups having 1 to 60 carbon atoms, hydrocarbylamide groups having 1 to 60 carbon atoms, hydrocarbyl phosphide groups having 1 to 60 carbon atoms, hydrocarbyl sulfides, silyl groups having 1 to 60 carbon atoms, and complex groups thereof.

[0079] The neutral Lewis base coordinating compound X in the compound (formula 3) above 2 Examples of such compounds, though not limited to them, include phosphines, ethers, amines, olefins with 2 to 40 carbon atoms, dienes with 1 to 40 carbon atoms, and divalent groups derived from these compounds.

[0080] The structure of the transition metal compound component [B-1] used in this embodiment is not particularly limited, but from the viewpoint of reducing the mobility of the branched chains of polyethylene, it is preferable to use a compound that can polymerize ultra-high molecular weight polyethylene.

[0081] Specific examples of the transition metal compound component [B-1] used in this embodiment are not particularly limited, but include, for example, the compounds shown below. Bis(methylcyclopentadienyl)zirconiumdimethyl Bis(n-butylcyclopentadienyl)zirconiumdimethyl, Bis(indenyl)zirconiumdimethyl, Bis(1,3-dimethylcyclopentadienyl)zirconium dimethyl, (Pentamethylcyclopentadienyl)(cyclopentadienyl)zirconium dimethyl, Bis(cyclopentadienyl)zirconiumdimethyl, Bis(pentamethylcyclopentadienyl)zirconiumdimethyl Bis(fluorenyl)zirconiumdimethyl, Bis(methylcyclopentadienyl)titaniumdimethyl, Bis(n-butylcyclopentadienyl)titaniumdimethyl, Bis(indenyl)titaniumdimethyl, Bis(1,3-dimethylcyclopentadienyl)titaniumdimethyl, (Pentamethylcyclopentadienyl)(cyclopentadienyl)titaniumdimethyl, Bis(cyclopentadienyl)titaniumdimethyl, Bis(pentamethylcyclopentadienyl)titaniumdimethyl, Bis(fluorenyl)titaniumdimethyl, Ethylene bis(indenyl) zirconium dimethyl, Ethylene bis(4,5,6,7-tetrahydro-1-indenyl) zirconium dimethyl, Ethylene bis(4-methyl-1-indenyl) zirconium dimethyl, Ethylene bis(5-methyl-1-indenyl) zirconium dimethyl, Ethylene bis(6-methyl-1-indenyl) zirconium dimethyl, Ethylene bis(7-methyl-1-indenyl) zirconium dimethyl, Ethylene bis(5-methoxy-1-indenyl)zirconium dimethyl, Ethylene bis(2,3-dimethyl-1-indenyl) zirconium dimethyl, Ethylene bis(4,7-dimethyl-1-indenyl) zirconium dimethyl, Ethylenebis-(4,7-dimethoxy-1-indenyl)zirconiumdimethyl, Methylenebis(cyclopentadienyl)zirconiumdimethyl Isopropylidene (cyclopentadienyl) zirconium dimethyl Isopropylidene (cyclopentadienyl-fluorenyl) zirconium dimethyl, Silylenebis(cyclopentadienyl)zirconiumdimethyl Dimethylsilylene (cyclopentadienyl) zirconium dimethyl [(Nt-butylamide)(tetramethyl-η5-cyclopentadienyl)-1,2-ethanediyl]titaniumdimethyl, [(Nt-butylamide)(tetramethyl-η5-cyclopentadienyl)dimethylsilane]titaniumdimethyl, [(N-methylamide)(tetramethyl-η5-cyclopentadienyl)dimethylsilane]titaniumdimethyl, [(N-phenylamide)(tetramethyl-η5-cyclopentadienyl)dimethylsilane]titaniumdimethyl, [(N-benzylamide)(tetramethyl-η5-cyclopentadienyl)dimethylsilane]titaniumdimethyl, [(Nt-butylamide)(η5-cyclopentadienyl)-1,2-ethanediyl]titaniumdimethyl, [(Nt-butylamide)(η5-cyclopentadienyl)dimethylsilane]titaniumdimethyl, [(N-methylamide)(η5-cyclopentadienyl)-1,2-ethanediyl]titaniumdimethyl, [(N-methylamide)(η5-cyclopentadienyl)dimethylsilane]titaniumdimethyl [(Nt-butylamide)(η5-indenyl)dimethylsilane]titanium dimethyl, [(N-benzylamide)(η5-indenyl)dimethylsilane]titanium dimethyl, Dibromobistriphenylphosphine nickel, Dichlorobistriphenylphosphine nickel, Nickel dibromodiacetonitrile, Dibromodibenzonitrile nickel, Dibromo(1,2-bisdiphenylphosphinoethane)nickel, Dibromo(1,3-bisdiphenylphosphinopropane)nickel, Dibromo(1,1'-diphenylbisphosphinoferocene)nickel, Dimethylbis-diphenylphosphine nickel, Dimethyl(1,2-bisdiphenylphosphinohethane)nickel, Methyl(1,2-bisdiphenylphosphinoethane)nickeltetrafluoroborate, (2-diphenylphosphino-1-phenylethyleneoxy)phenylpyridine nickel, Dichlorobistriphenylphosphine palladium, Dichlorodibenzonitrile palladium, dichlorodiacetonitrile palladium, Dichloro(1,2-bisdiphenylphosphinoethane)palladium, Bistriphenylphosphine palladium bistetrafluoroborate, Bis(2,2'-bipyridine)methyl iron tetrafluoroborate etherate, etc.

[0082] The transition metal compound component [B-1] used in this embodiment is not particularly limited, but for example, the "dimethyl" part of the names of each zirconium and titanium compound listed above (this is the part at the end of the name of each compound, that is, immediately after the part "zirconium" or "titanium", and X in (Equation 3) above) 1 Ya X 2 Compounds whose names can be obtained by replacing the part corresponding to the above with any of the following: "Dichlor", "Zibrom", "Jiod", "Diethyl", "Dibutyl", "Diphenyl", "Dibenzil", "2-(N,N-dimethylamino)benzyl", "2-buten-1,4-jil", "s-trans-η4-1,4-diphenyl-1,3-butadiene", "s-trans-η4-3-methyl-1,3-pentadiene", "s-trans-η4-1,4-dibenzyl-1,3-butadiene", "s-trans-η4-2,4-hexadiene", "s-trans-η4-1,3-pentadiene", "s-trans-η4-1,4-ditril-1,3-butadiene", "s-trans-η4-1,4-bis(trimethylsilyl)-1,3-butadiene", "s-cis-η4-1,4-diphenyl-1,3-butadiene", "s-cis-η4-3-methyl-1,3-pentadiene", "s-cis-η4-1,4-dibenzyl-1,3-butadiene", "s-cis-η4-2,4-hexadiene", "s-cis-η4-1,3-pentadiene", "s-cis-η4-1,4-ditril-1,3-butadiene", "s-cis-η4-1,4-bis(trimethylsilyl)-1,3-butadiene," etc.

[0083] A specific example of such a transition metal compound component [B-1] is bis(pentamethylcyclopentadienyl)titanium dichloride.

[0084] The transition metal compound component [B-1] used in this embodiment is not particularly limited and can be synthesized by generally known methods.

[0085] Next, the transition metal compound component [B-2] used in this embodiment will be described. The transition metal compound component [B-2] is not particularly limited, but from the viewpoint of macromonomer incorporation efficiency, the compound represented by the following formula (Equation 4) is preferred. [ka] (In the formula, M 2 This represents a transition metal selected from the group consisting of titanium, zirconium, and hafnium, whose formal oxidation number is +2, +3, or +4. R 5 Each of these independently represents a substituent having 1 to 20 non-hydrogen atoms, selected from the group consisting of hydrogen atoms, hydrocarbon groups having 1 to 8 carbon atoms, silyl groups, germyl groups, cyano groups, halogen atoms, and composite groups thereof, provided that the substituent R 5When is a hydrocarbon group having 1 to 8 carbon atoms, a silyl group, or a gelmyl group, there may be two adjacent substituents R 5 These two atoms bond to each other to form a divalent group, thereby the two adjacent substituents R 5 The bonds between the two carbon atoms of the cyclopentadienyl rings bonded to each of them cooperate to form rings, X 3 Each of these independently represents a substituent having 1 to 20 nonhydrogen atoms, selected from the group consisting of halides, hydrocarbon groups having 1 to 20 carbon atoms, hydrocarbyloxy groups having 1 to 18 carbon atoms, hydrocarbylamino groups having 1 to 18 carbon atoms, silyl groups, hydrocarbylamide groups having 1 to 18 carbon atoms, hydrocarbylphosphine groups having 1 to 18 carbon atoms, hydrocarbyl sulfide groups having 1 to 18 carbon atoms, and composite groups thereof, provided that there may be two substituents X. 3 These groups cooperate to form a neutral conjugated diene or divalent group with 4 to 30 carbon atoms. Y 1 -O-, -S-, -NR 6 - or -PR 6 - represents, however, R 6 This represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, a hydrocarbyloxy group having 1 to 8 carbon atoms, a silyl group, an alkyl halide having 1 to 8 carbon atoms, an aryl halide having 6 to 20 carbon atoms, or a composite group thereof. Z 1 is SiR 6 2. CR 6 2. SiR 6 2SiR 6 2. CR 6 2CR 6 2. CR 6 =CR 6 , CR 6 2SiR 6 2 or GeR 6 Represents 2, however R 6 As defined above, n is 1, 2, or 3.

[0086] Specific examples of the transition metal compound component [B-2] used in this embodiment are not particularly limited, but include, for example, the compounds shown below. [(Nt-butylamide)(tetramethyl-η5-cyclopentadienyl)-1,2-ethanediyl]titaniumdimethyl, [(Nt-butylamide)(tetramethyl-η5-cyclopentadienyl)dimethylsilane]titaniumdimethyl, [(N-methylamide)(tetramethyl-η5-cyclopentadienyl)dimethylsilane]titaniumdimethyl, [(N-phenylamide)(tetramethyl-η5-cyclopentadienyl)dimethylsilane]titaniumdimethyl, [(N-benzylamide)(tetramethyl-η5-cyclopentadienyl)dimethylsilane]titaniumdimethyl, [(Nt-butylamide)(η5-cyclopentadienyl)-1,2-ethanediyl]titaniumdimethyl, [(Nt-butylamide)(η5-cyclopentadienyl)dimethylsilane]titaniumdimethyl, [(N-methylamide)(η5-cyclopentadienyl)-1,2-ethanediyl]titaniumdimethyl, [(N-methylamide)(η5-cyclopentadienyl)dimethylsilane]titaniumdimethyl [(Nt-butylamide)(η5-indenyl)dimethylsilane]titanium dimethyl, [(N-benzylamide)(η5-indenyl)dimethylsilane]titaniumdimethyl, etc.

[0087] The transition metal compound component [B-2] used in this embodiment is not particularly limited, but for example, the "dimethyl" part of the names of each titanium compound listed above (this is the part at the end of the name of each compound, that is, immediately after the "titanium" part, and X in (Equation 4) above) 3 Compounds whose names can be obtained by replacing the part corresponding to the above with any of the following: "Dichlor", "Zibrom", "Jiod", "Diethyl", "Dibutyl", "Diphenyl", "Dibenzil", "2-(N,N-dimethylamino)benzyl", "2-buten-1,4-jil", "s-trans-η4-1,4-diphenyl-1,3-butadiene", "s-trans-η4-3-methyl-1,3-pentadiene", "s-trans-η4-1,4-dibenzyl-1,3-butadiene", "s-trans-η4-2,4-hexadiene", "s-trans-η4-1,3-pentadiene", "s-trans-η4-1,4-ditril-1,3-butadiene", "s-trans-η4-1,4-bis(trimethylsilyl)-1,3-butadiene", "s-cis-η4-1,4-diphenyl-1,3-butadiene", "s-cis-η4-3-methyl-1,3-pentadiene", "s-cis-η4-1,4-dibenzyl-1,3-butadiene", "s-cis-η4-2,4-hexadiene", "s-cis-η4-1,3-pentadiene", "s-cis-η4-1,4-ditril-1,3-butadiene", "s-cis-η4-1,4-bis(trimethylsilyl)-1,3-butadiene," etc.

[0088] A specific example of such a transition metal compound component [B-2] is the [(Nt-butylamide)(tetramethyl-η5-cyclopentadienyl)dimethylsilane]titanium complex.

[0089] The transition metal compound component [B-2] used in this embodiment is not particularly limited and can be synthesized by generally known methods.

[0090] Next, we will describe the activator [C] and organometallic compound component [D] that can form a complex that exhibits catalytic activity in reaction with the transition metal compound used in this embodiment.

[0091] The activator [C] in this embodiment is not particularly limited, but examples include the compound (C-1) defined in the following formula (Equation 5). (C-1):[L 2 -H] d+ [M 3 r Q s ] d- ...(Formula 5) However, in the formula [L 2 -H] d+ It is a proton-donating Brønsted acid, L 2 [M is a neutral Lewis base. Also, in the formula, [M 3 r Q s ] d- M is a compatible non-coordinating anion. 3 Q is a metal or metalloid selected from groups 5 through 15 of the periodic table, and each Q is independently a hydride, dialkylamide group, halide, alkoxide group, allinoxide group, hydrocarbon group, or substituted hydrocarbon group with up to 20 carbon atoms, and there is no more than one halide Q. Also, r is an integer from 1 to 7, s is an integer from 2 to 14, and d is an integer from 1 to 7, and sr = d.

[0092] Non-coordinating anions are not particularly limited, but examples include the following compounds. Tetrakisphenylborate, Tri(p-tolyl)(phenyl)borate, Tris(pentafluorophenyl)(phenyl)borate, Tris(2,4-dimethylphenyl)(hydrophenyl)borate, Tris(3,5-dimethylphenyl)(phenyl)borate, Tris(3,5-di-trifluoromethylphenyl)(phenyl)borate, Tris(pentafluorophenyl)(cyclohexyl)borate, Tris(pentafluorophenyl)(naphthyl)borate, Tetrakis(pentafluorophenyl)borate, Triphenyl(hydroxyphenyl) borate, Diphenyl-di(hydroxyphenyl)borate, Triphenyl(2,4-dihydroxyphenyl)borate, Tri(p-tolyl)(hydroxyphenyl)borate, Tris(pentafluorophenyl)(hydroxyphenyl)borate, Tris(2,4-dimethylphenyl)(hydroxyphenyl)borate, Tris(3,5-dimethylphenyl)(hydroxyphenyl)borate, Tris(3,5-di-trifluoromethylphenyl)(hydroxyphenyl)borate, Tris(pentafluorophenyl)(2-hydroxyethyl)borate, Tris(pentafluorophenyl)(4-hydroxybutyl)borate, Tris(pentafluorophenyl)(4-hydroxycyclohexyl)borate, Tris(pentafluorophenyl)(4-(4'-hydroxyphenyl)phenyl)borate, Tris(pentafluorophenyl)(6-hydroxy-2-naphthyl)borate, Tris(pentafluorophenyl)(4-hydroxyphenyl)borate, etc.

[0093] Other preferred non-coordinating anions include, but are not limited to, borates in which the hydroxyl group of the borate described above is replaced with an NHR group, where R is preferably a methyl group, an ethyl group, or a tert-butyl group.

[0094] Furthermore, while there are no particular limitations on the proton-donating Brønsted acid, examples include trialkyl-substituted ammonium cations such as triethylammonium, tripropylammonium, tri(n-butyl)ammonium, trimethylammonium, tributylammonium, and tri(n-octyl)ammonium. N,N-dialkylanilinium cations such as N,N-dimethylanilinium, N,N-diethylanilinium, N,N-2,4,6-pentamethylanilinium, and N,N-dimethylbenzylanilinium are also preferred. Dialkylammonium cations such as di-(i-propyl)ammonium and dicyclohexylammonium are also preferred, as are triarylphosphonium cations such as triphenylphosphonium, tri(methylphenyl)phosphonium, and tri(dimethylphenyl)phosphonium, or dimethylsulfonium, diethylfluphonium, and diphenylsulfonium.

[0095] The activator (C-1) used in this embodiment may be a reaction product with an organoaluminum compound. The organoaluminum compound is not particularly limited, but examples include trimethylaluminum, triethylaluminum, tributylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, etc., or reaction products of these alkylaluminum compounds with alcohols such as methyl alcohol, ethyl alcohol, butyl alcohol, pentyl alcohol, hexyl alcohol, octyl alcohol, decyl alcohol, etc., such as dimethylmethoxyaluminum, diethylethoxyaluminum, dibutylbutoxyaluminum, etc. Furthermore, the reaction products with the above organoaluminum compounds may be used individually or in combination.

[0096] In this embodiment, an organometallic oxy compound (C-2) having a unit represented by the following formula (Formula 6) can also be used as the activator [C]. (C-2):-(M 4 R 7 t-2 -O)u -...(Formula 6) (However, M 4 These are metals or metalloids from groups 13 to 15 of the periodic table, and R 7 Each of these is independently a hydrocarbon group or substituted hydrocarbon group having 1 to 12 carbon atoms, and t is a metal M 4 (This is the valence of , where u is an integer greater than or equal to 2.)

[0097] The activator (C-2) is not particularly limited, but examples include organoaluminum oxy compounds shown in (Equation 7) below. [-Al(Me)-O-] v -[-Al(R 8 )-O-] w ...(Formula 7) In the formula, R 8 R is a carbide water group having 1 to 12 carbon atoms. In the above formula, R 8 The group is not particularly limited in specific terms, but examples include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, pentyl group, hexyl group, octyl group, decyl group, cyclohexyl group, and cyclooctyl group. Among these, methyl group and ethyl group are preferred, and methyl group is particularly preferred. In the above formula, for example, examples of organoaluminum oxy compounds composed of one type of alkylaluminum unit are not particularly limited, but examples include methylaluminoxane, ethylaluminoxane, n-propylaluminoxane, isopropylaluminoxane, n-butylaluminoxane, isobutylaluminoxane, pentylaluminoxane, hexylaluminoxane, octylaluminoxane, decylaluminoxane, cyclohexylaluminoxane, and cyclooctylaluminoxane. Among these, methylaluminoxane and ethylaluminoxane are preferred, and methylaluminoxane is particularly preferred.

[0098] As described above, the organoaluminum oxy compounds used in this embodiment are those composed of alkyloxyaluminum units represented by the above formula, but are not necessarily limited to compounds consisting of one type of constituent unit, and may consist of multiple types of constituent units. Specifically, although not particularly limited, examples include methylethylaluminoxane, methylpropylaluminoxane, methylbutylaluminoxane, etc., and the ratio of each constituent unit can be arbitrarily taken in the range of 0 to 100%. Alternatively, it may be a mixture of multiple types of organoaluminum oxy compounds consisting of one type of constituent unit. Specifically, although not particularly limited, examples include a mixture of methylaluminoxane and ethylaluminoxane, a mixture of methylaluminoxane and n-propylaluminoxane, a mixture of methylaluminoxane and isobutylaluminoxane, etc. Furthermore, v and w can be any numbers, but from the viewpoint of ease of manufacture, the ratio of v to w v / w is preferably 0.1 or more and 10 or less, and more preferably 0.3 or more and 5 or less.

[0099] Furthermore, the organoaluminum oxy compound used in this embodiment may contain unreacted chemical substances resulting from its manufacturing method. In other words, organoaluminum oxy compounds are generally obtained by the reaction of trialkylaluminum and H2O, but some of these raw materials may remain as unreacted chemical substances. Specifically, although not particularly limited, for example, in the synthesis of methylalkethane, trimethylaluminum and H2O are used as raw materials, and one or both of these raw materials may be contained in the methylalkethane as unreacted chemical substances. In the manufacturing method of the organoaluminum oxy compound exemplified above, trialkylaluminum is usually used in greater quantities than H2O, so trialkylaluminum is often contained in the organoaluminum oxy compound as a residual chemical substance.

[0100] In this embodiment, the organometallic compound component [D] is preferably a compound containing at least one metal selected from the group consisting of Groups 1, 2, 12, and 13 of the periodic table, and organoaluminum compounds and / or organomagnesium compounds are particularly preferred.

[0101] As the organoaluminum compound, it is preferable to use the compound represented by the following formula (8) alone or in combination. (D-1): AlR 8 l Z 2 (3-l)...(Equation 8) (In formula 8, R 8 This is a hydrocarbon group with 1 to 20 carbon atoms, Z 2 (where l is a group belonging to the group consisting of hydrogen, halogen, alkoxy, allyloxy, or siloxy groups, and l is a number between 2 and 3.)

[0102] In the above (Equation 8), R 8The hydrocarbon group having 1 to 20 carbon atoms represented by is not particularly limited, but examples include aliphatic hydrocarbons, aromatic hydrocarbons, or alicyclic hydrocarbons. Specifically, preferred examples include trialkylaluminum such as trimethylaluminum, triethylaluminum, tripropylaluminum, tributylaluminum, tri(2-methylpropyl)aluminum (or triisobutylaluminum), tripentylaluminum, tri(3-methylbutyl)aluminum, trihexylaluminum, trioctylaluminum, and tridecylaluminum; aluminum halide compounds such as diethylaluminum chloride, ethylaluminum dichloride, bis(2-methylpropyl)aluminum chloride, ethylaluminum sesquichloride, and diethylaluminum bromide; alkoxyaluminum compounds such as diethylaluminum ethoxide and bis(2-methylpropyl)aluminum butoxide; siloxyaluminum compounds such as dimethylhydrosiloxyaluminum dimethyl, ethylmethylhydrosiloxyaluminum diethyl, and ethyldimethylsiloxyaluminum diethyl, and mixtures thereof. Trialkylaluminum compounds are particularly preferred. As the organomagnesium compound, it is preferable to use the organomagnesium compound (A-1) represented by (Formula 1) above, either alone or in combination.

[0103] In the above (Equation 1), γ, δ, e, f, g, M 1 , R 1 , R 2 , OR 3 As has already been mentioned, this organomagnesium compound is preferable to have high solubility in inert hydrocarbon solvents, so β / α is preferably in the range of 0.5 to 10, and M 1 Compounds in which aluminum is present are even more preferred.

[0104] As an alternative organomagnesium compound, the organomagnesium compound (D-2) represented by the following formula (9) can be used alone or in combination. (D-2):(M 5) α (Mg) β (R 9 ) a (R 10 ) b Y 2 c ...(Formula 9) (In formula 9, M 5 R is a metal atom belonging to the group consisting of groups 12, 13, and 14 of the periodic table. 9 and R 10 Y is a hydrocarbon group having 2 to 20 carbon atoms. 2 Alkoxy, siloxy, allyloxy, amino, amide, -N=CR 11 ,R 12 , -SR 13 (Here, R 11 , R 12 and R 13 represents a hydrocarbon group with 1 to 20 carbon atoms. When c is 2, Y 2 These may be different from each other.) α is one of the β-keto acid residues, and α, β, a, b, and c are real numbers satisfying the following relationship: 0 ≤ α, 0 < β, 0 ≤ a, 0 ≤ b, 0 ≤ c, 0 <a+b、0≦c / (α+β)≦2、mα+2β=a+b+c(ここで、mはM 5 This represents the valence of an atom.

[0105] Next, an example of a method for producing a polyethylene polymerization catalyst from inorganic solid particles [A], a transition metal compound component [B-1], a transition metal compound component [B-2], and an activator [C] and / or an organometallic compound component [D] will be described.

[0106] In this embodiment, although not particularly limited, a polyethylene polymerization catalyst is produced by reacting inorganic solid particles [A] with a transition metal compound component [B-1], a transition metal compound component [B-2], an activator [C], and / or an organometallic compound component [D].

[0107] The reaction is preferably carried out in an inert hydrocarbon solvent. The inert hydrocarbon solvent is not particularly limited, but specific examples include aliphatic hydrocarbons such as pentane, hexane, and heptane; aromatic hydrocarbons such as benzene and toluene; and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane. Among these, it is even more preferable to carry out the reaction in an aliphatic hydrocarbon solvent such as hexane or heptane.

[0108] In this reaction, from the viewpoint of reaction efficiency, it is preferable to dissolve the transition metal compound components [B-1] and [B-2] in an inert hydrocarbon solvent before using them in the reaction. The concentration at which they are dissolved is not particularly limited, but from the viewpoint of avoiding segregation on the surface of the inorganic solid particles [A], a concentration of 0.01 mol / L to 5 mol / L is preferred, and a concentration of 0.05 mol / L to 2 mol / L is more preferred.

[0109] In this reaction, it is possible to use only one of the transition metal compound components [B-1] and [B-2], but from the viewpoint of controlling the amount of long-chain branching in polyethylene, it is preferable to use both.

[0110] In this reaction, it is preferable to vary the type and amount of each transition metal compound component for the activator [C] and organometallic compound component [D], from the viewpoint of facilitating control of the long-chain branching of polyethylene. Furthermore, while there are no particular limitations on the concentrations of the activator [C] and organometallic compound component [D], from the viewpoint of reactivity with the transition metal compound component, a concentration of 0.01 mol / L to 5 mol / L is preferred, and 0.05 mol / L to 2 mol / L is more preferred. It is preferable to use an inert hydrocarbon solvent for diluting the activator [C] and organometallic compound component [D].

[0111] In this reaction, the method of adding the transition metal compound component [B-1], transition metal compound component [B-2], activator [C], and organometallic compound component [D] is not particularly limited. However, from the viewpoint of forming layers of the transition metal compound component and the activator and / or organometallic compound component, it is preferable to add a pre-mixed mixture of the transition metal compound component and the activator and / or organometallic compound component to the inorganic solid particles [A], or to add the transition metal compound component and the activator and / or organometallic compound component simultaneously to the inorganic solid particles [A]. Furthermore, from the viewpoint of incorporating the macromonomer generated from the transition metal compound component [B-1] into the transition metal compound component [B-2], it is preferable to add the transition metal compound component [B-1] activated by the activator [C] and / or organometallic compound component [D] to the inorganic solid particles [A], and then add the transition metal compound component [B-2] activated by the activator [C] and / or organometallic compound component [D].

[0112] The reaction temperature is not particularly limited, but from the viewpoint of reaction efficiency, it is preferably between -20°C and 100°C, and more preferably between 0°C and 80°C.

[0113] In this reaction, the molar ratio ([B-2] / [B-1]) of the transition metal compound component [B-1] to the transition metal compound component [B-2] is not particularly limited, but from the viewpoint of controlling the amount of long-chain branching of polyethylene to a minute extent, it is preferably 1 to 1000 and more preferably 5 to 100.

[0114] In this reaction, the molar ratio ([C] / [B-1]) of the transition metal compound component [B-1] to the activator [C] is not particularly limited, but when the activator [C] is (C-1), it is preferably 0.1 to 1 and more preferably 0.1 to 0.5, from the viewpoint of controlling the amount of long-chain branching of polyethylene to a minute extent.

[0115] In this reaction, the molar ratio ([C] / [B-1]) of the transition metal compound component [B-1] to the activator [C] is not particularly limited, but when the activator [C] is (C-2), it is preferably 1 to 60, and more preferably 1 to 30, from the viewpoint of controlling the amount of long-chain branching in polyethylene to a minute extent and suppressing the amount of metal residue in polyethylene.

[0116] In this reaction, the molar ratio ([D] / [B-1]) of the transition metal compound component [B-1] to the organometallic compound component [D] is not particularly limited, but from the viewpoint of controlling the amount of long-chain branching in polyethylene to a minute extent and suppressing the amount of metal residue in polyethylene, it is preferably 1 to 60 and more preferably 1 to 30.

[0117] In this reaction, the molar ratio ([C] / [B-2]) of the transition metal compound component [B-2] to the activator [C] is not particularly limited, but when the activator [C] is (C-1), it is preferably 0.5 to 1.5, and more preferably 0.9 to 1.1, from the viewpoint of controlling the amount of long-chain branching of polyethylene to a minute extent.

[0118] In this reaction, the molar ratio ([C] / [B-2]) of the transition metal compound component [B-2] to the activator [C] is not particularly limited, but when the activator [C] is (C-2), it is preferable that the ratio be between 2 and 200, and more preferably between 5 and 100, from the viewpoint of controlling the amount of long-chain branching in polyethylene to a minute extent and suppressing the amount of metal residue in polyethylene.

[0119] In this reaction, the molar ratio ([D] / [B-1]) of the transition metal compound component [B-2] to the organometallic compound component [D] is not particularly limited, but from the viewpoint of controlling the amount of long-chain branching in polyethylene to a minute extent and suppressing the amount of metal residue in polyethylene, it is preferably 1 to 60 and more preferably 1 to 30.

[0120] Next, we will describe the impurity scavenger used in the polymerization of polyethylene powder in this embodiment. The impurity scavenger used in the polymerization of polyethylene powder in this embodiment is not particularly limited, but it is preferable to use the organometallic compound component [D]. There are no particular restrictions on the method of adding the organometallic compound component [D] into a polymerization system under polymerization conditions. It may be added to the polymerization system separately from the catalyst component, or it may be added to the polymerization system after being reacted with the catalyst component beforehand.

[0121] The concentration of the organometallic compound component [D] in the polymerization system is not particularly limited, but from the viewpoint of completely capturing impurities and the amount of metal residue in the polymer, it is preferably 0.001 mmol / L to 10 mmol / L, more preferably 0.01 mmol / L to 5 mmol / L, and even more preferably 0.05 mmol / L to 2 mmol / L.

[0122] In this embodiment, the organometallic compound component [D] may be used alone or in a mixture of two or more types.

[0123] (Methods for polymerizing ethylene polymers) The polymerization method for the ethylene-based polymer constituting the polyethylene powder of this embodiment is not particularly limited, but examples include polymerizing ethylene by suspension polymerization or gas-phase polymerization, or copolymerizing ethylene with a comonomer. Among these, suspension polymerization, which can efficiently remove the heat of polymerization, is preferred.

[0124] In suspension polymerization, an inert hydrocarbon medium can be used as the solvent, and the olefin itself can also be used as the solvent.

[0125] The inert hydrocarbon medium is not particularly limited, but examples include aliphatic hydrocarbons such as propane, butane, isobutane, pentane, isopentane, hexane, heptane, octane, decane, dodecane, and kerosene; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane; aromatic hydrocarbons such as benzene, toluene, and xylene; halogenated hydrocarbons such as ethyl chloride, chlorobenzene, and dichloromethane, or mixtures thereof.

[0126] In this embodiment, the polymerization temperature for ethylene polymerization is usually preferably 30°C to 100°C, more preferably 35°C to 95°C, and particularly preferably 40°C to 90°C. A polymerization temperature of 30°C or higher enables industrially efficient production. On the other hand, a polymerization temperature of 100°C or lower suppresses the formation of lumpy scale that occurs when a portion of the polymer melts, enabling continuous and stable production without clogging of pipes.

[0127] In the polyethylene powder production method of this embodiment, the polymerization pressure of the ethylene polymer is preferably above atmospheric pressure and 2 MPaG or less, more preferably between 0.2 MPaG and 1.5 MPaG, and even more preferably between 0.3 MPaG and 0.9 MPaG.

[0128] When the polymerization pressure is above atmospheric pressure, industrially efficient production becomes possible. On the other hand, when the polymerization pressure is 2 MPaG or less, stable production tends to be possible without generating clumpy scale due to rapid polymerization in the polymerization reactor.

[0129] Generally, when polymerizing ethylene-based polymers, antistatic agents such as Stadis or STATSAFE from Innospec (distributed by Maruwa Bussan) can be used to suppress the electrostatic adhesion of the polymer to the polymerization reactor.

[0130] Antistatic agents such as Stadis and STATSAFE can be added to the polymerization reactor by pump or the like after being diluted in an inert hydrocarbon medium. The addition of the antistatic agent can be done by adding it to the solid catalyst in advance or by adding it to the polymerization reactor. The amount added is preferably 1 ppm to 500 ppm, and more preferably 10 ppm to 100 ppm, relative to the amount of ethylene polymer produced per unit time.

[0131] The molecular weight of ethylene polymers can be controlled by introducing hydrogen into the polymerization system or by changing the polymerization temperature, as described in West German Patent Application Publication No. 3127133. By adding hydrogen as a chain transfer agent to the polymerization system, it is possible to control the molecular weight of ethylene polymers within an appropriate range. When hydrogen is added to the polymerization system, the mole fraction of hydrogen is preferably 0 mol% to 50 mol%, more preferably 0 mol% to 30 mol%, and even more preferably 0 mol% to 20 mol%.

[0132] Furthermore, when adding hydrogen to the polymerization system, it is also possible to contact the catalyst beforehand and then add the hydrogen to the polymerization system through the catalyst introduction line. Immediately after introducing the catalyst into the polymerization system, the catalyst concentration near the outlet of the introduction line becomes high, which can lead to rapid polymerization and an increased likelihood of localized high temperatures. On the other hand, by contacting the hydrogen with the catalyst before introducing it into the polymerization system, it is possible to suppress the initial activity of the catalyst, thereby preventing the formation of clumpy scale due to rapid polymerization and catalyst deactivation at high temperatures.

[0133] In addition to the components described above, this embodiment may also include other known components useful for the production of polyethylene.

[0134] Polymerization reactions can be carried out using batch, semi-continuous, or continuous methods, with continuous methods being preferred.

[0135] By continuously supplying ethylene gas, solvents, catalysts, etc., into the polymerization system and continuously discharging them along with the generated ethylene polymer, it is possible to suppress the rapid ethylene reaction that causes partial high temperatures, thereby stabilizing the polymerization system.

[0136] When ethylene reacts uniformly within the polymerization system, the formation of branching and double bonds in the polymer chain is suppressed, and the generation of low-molecular-weight or ultra-high-molecular-weight components through decomposition or crosslinking of the ethylene polymer is also suppressed, making it easier to form crystalline components of the ethylene-based polymer. This makes it easier to obtain a sufficient amount of crystalline components necessary to achieve the strength required for microporous films and the like.

[0137] Furthermore, the polymerization reaction of the ethylene polymer may be a single-stage polymerization method using one polymerization reactor, or a multi-stage polymerization method in which polymerization is carried out sequentially and continuously using two or more polymerization reactors connected in series.

[0138] The suspension containing the ethylene-based polymer that constitutes the polyethylene powder of this embodiment is quantitatively withdrawn from the polymerization reactor and transferred to a flash tank, where unreacted ethylene, hydrogen, and comonomers (only when copolymerization is performed in the reactor) are separated.

[0139] In the polymerization process of polyethylene powder in this embodiment, any of the following methods can be applied for solvent separation: decantation, centrifugation, filter filtration, etc. However, centrifugation is more preferable because it provides better separation efficiency between the ethylene polymer and the solvent.

[0140] The method for deactivating the catalyst used in the polymerization step of the ethylene-based polymer constituting the polyethylene powder of this embodiment is not particularly limited, but it is preferable to deactivate the catalyst after separating the ethylene-based polymer from the solvent.

[0141] By introducing an agent to deactivate the catalyst after separating the polyethylene powder from the solvent, it is possible to suppress the precipitation of low molecular weight components and catalyst components contained in the solvent within the ethylene polymer.

[0142] The agents used to deactivate the catalyst are not particularly limited, but examples include oxygen, water, alcohols, glycols, phenols, carbon monoxide, carbon dioxide, ethers, carbonyl compounds, alkynes, and the like.

[0143] In the polyethylene powder production method of this embodiment, it is preferable to separate the ethylene polymer from the solvent and then carry out a drying step. In the drying step, it is preferable to use a rotary kiln, paddle dryer, or fluidized bed dryer. Furthermore, the drying temperature is preferably 50°C to 150°C, and more preferably 70°C to 110°C.

[0144] Furthermore, introducing an inert gas such as nitrogen into the dryer to accelerate drying is also effective. In this case, adding steam or other chemicals to deactivate the catalyst is even more effective.

[0145] After drying the ethylene-based polymer that constitutes the polyethylene powder of this embodiment, it may be sieved to remove coarse powder.

[0146] The polyethylene powder of this embodiment may be a mixture of multiple polyethylene powders containing an ethylene-based polymer obtained by the manufacturing method described above.

[0147] Furthermore, if necessary, it may be used in combination with known additives such as slip agents, neutralizing agents, antioxidants, light stabilizers, antistatic agents, and pigments.

[0148] The slip agent or neutralizing agent is not particularly limited, but examples include aliphatic hydrocarbons, higher fatty acids, higher fatty acid metal salts, fatty acid esters of alcohols, waxes, higher fatty acid amides, silicone oils, rosin, etc. Specifically, stearates such as calcium stearate, magnesium stearate, and zinc stearate can be listed as suitable additives.

[0149] The antioxidant is not particularly limited, but for example, phenolic compounds or phenolic phosphate compounds are preferred. Specifically, examples include phenolic antioxidants such as 2,6-di-t-butyl-4-methylphenol (dibutylhydroxytoluene), n-octadecyl-3-(4-hydrox-3,5-di-t-butylphenyl)propionate, and tetrakis(methylene(3,5-di-t-butyl-4-hysaloxyhydrocinnamate))methane; phenol-phosphorus antioxidants such as 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenzo[d,f][1,3,2]dioxaphosfepin; and phosphorus antioxidants such as tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene-diphosphonite, tris(2,4-di-t-butylphenyl)phosphite, and cyclic neopentanetetraylbis(2,4-t-butylphenyl phosphite).

[0150] Examples of light stabilizers are not particularly limited, but include benzotriazole-based light stabilizers such as 2-(5-methyl-2-hydroxyphenyl)benzotriazole and 2-(3-t-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole; and hindered amine-based light stabilizers such as bis(2,2,6,6-tetramethyl-4-piperidine) sebacate and poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}].

[0151] Antistatic agents are not particularly limited, but examples include aluminosilicates, kaolin, clay, natural silica, synthetic silica, silicates, talc, diatomaceous earth, and glycerin fatty acid esters.

[0152] [Application] The polyethylene powder of this embodiment can be used as a raw material for various molded products such as microporous membranes, fibers, especially high-strength fibers, sintered bodies, press-molded bodies, and ram-pressed bodies.

[0153] In particular, the polyethylene powder of this embodiment is suitable as a raw material for microporous membranes used in battery separators.

[0154] [Molded body] The molded article of this embodiment is a molded article of the polyethylene powder of this embodiment as described above.

[0155] The molded body is not particularly limited, but examples include microporous membranes, especially microporous membranes used as battery separators, fibers, especially high-strength fibers, sintered bodies, press-molded bodies, ram-pressed bodies, and the like.

[0156] The method for manufacturing a molded article is not particularly limited, but examples include a molding method that involves the steps of extruding, stretching, extracting, and drying a resin using a wet extrusion method.

[0157] The aforementioned battery separators are not particularly limited, but examples include separators for lithium-ion secondary batteries and separators for lead-acid batteries. [Examples]

[0158] The present invention will be described in more detail below with reference to specific examples and comparative examples, but the present invention is not limited in any way by the following examples and comparative examples.

[0159] First, I will explain how to evaluate the physical properties of polyethylene powder. [Physical properties of polyethylene powder] (Viscosity average molecular weight (Mv)) The viscosity-average molecular weight of polyethylene powder was measured according to ISO 1628-3 (2010) by the method described below. First, polyethylene powder was weighed into a dissolution tube within the range of 4.0 to 4.5 mg. The weighed mass is denoted as "m (unit: mg)" in the following formula. Next, the air inside the dissolution tube was degassed using a vacuum pump and replaced with nitrogen. Then, 20 mL of decahydronaphthalene (prepared by adding 1 g / L of 2,6-di-t-butyl-4-methylphenol, degassing with a vacuum pump, and replacing with nitrogen; hereinafter referred to as decalin) was added, and the mixture was stirred at 150°C for 90 minutes to dissolve the polyethylene powder and obtain a decalin solution. Subsequently, the decalin solution was placed in a constant temperature liquid bath at 135°C and placed into a Cannon-Fenske viscometer (manufactured by Shibata Scientific Instruments Co., Ltd. / viscometer number: 100), and the drop time between the markings (t s ) was measured. Furthermore, the drop time (t) of Decalin alone, without polyethylene powder as a blank. b ) is measured and the specific viscosity (η) is measured according to (formula A) below. sp ) was sought. η sp =( t s / t b )-1 (Formula A) Specific viscosity (η sp The intrinsic viscosity IV ([η]) was calculated from the following (Equation B) and (Equation C) values: (a) and (b) (a) (unit: g / dL). Concentration C = m / (20 × γ) / 10 (unit: g / dL) (Formula B) γ = (density of decalin at 20°C) / (density of decalin at 135°C) =0.888 / 0.802=1.107 Intrinsic viscosity IV=(η sp / C) / (1+0.27×η sp (Formula C) The viscosity-average molecular weight (Mv) was calculated by substituting this intrinsic viscosity IV into the following equation (Equation D). Viscosity average molecular weight (Mv)=(5.34×10 4 )×[η] 1.49 (Formula D)

[0160] (Temperature difference between the peak top temperature and the peak convergence point in the DSC curve during the second heating process (crystal thickness parameter)) The following method was used to determine the values ​​using a differential scanning calorimeter (PerkinElmer, product name: DSC8000). First, an aluminum pan containing 8.5 mg of polyethylene powder was placed in the heating furnace of the DSC apparatus, and the heating operation was performed according to the following <measurement conditions>. However, the heating operation was performed entirely under a nitrogen atmosphere. <Measurement conditions> (1) Leave standing at 50°C for 1 minute. (2) Increase the temperature from 50°C to 180°C at a rate of 10°C / min (first heating step) (3) Let stand at 180°C for 5 minutes. (4) Cool from 180°C to 50°C at 10°C / min (5) Let stand at 50°C for 5 minutes. (6) Increase the temperature from 50°C to 180°C at a rate of 10°C / min (second heating step) Then, in the endothermic peak obtained during the second heating process, the temperature (Tm2) that indicates the peak top top ) and the point of convergence of the peaks (Tm2 end ) was sought. Finally, the values ​​of each temperature were substituted into the following equation (Equation E) to calculate the temperature difference (crystal thickness parameter) between the peak top temperature and the peak convergence point in the DSC curve during the second heating process. (Temperature difference)=Tm2 end -Tm2 top (Formula E) Note: Tm2 end The following procedure was used to calculate it. <Tm2 end Calculation procedure > (1) Differentiate the amount of heat absorbed during the second heating process with respect to temperature. (2) For the absolute value of the derivative obtained in (1), Tm2 top Starting from that point, the temperature at which it first drops below 0.01 is Tm2. end That's what I decided.

[0161] (z-mean contraction factor g) z ) Using a gel permeation chromatography (GPC) measurement apparatus (manufactured by Agilent Technologies, model name: PL-GPC220) equipped with a differential refractometer (RI) and a viscometer, it was calculated by the method shown below. First, a predetermined amount of polyethylene powder was added to 1,2,4-trichlorobenzene (manufactured by Fujifilm Wako Pure Chemical Corporation, with 4,4'-thiobis(2-t-butyl-5-methylphenol) added at a concentration of 125 mg / L). At this time, the concentration was adjusted as shown in the following <Sample Concentration>. <Sample Concentration> When Mv is less than 300,000: 10 mg / 10 mL When Mv is 300,000 or more and less than 1,000,000: 3 mg / 10 mL When Mv is 1,000,000 or more and less than 2,000,000: 2 mg / 10 mL When Mv is 2,000,000 or more and less than 3,000,000: 1.5 mg / 10 mL When Mv is 3,000,000 or more: 1.5 mg / 15 mL Furthermore, the prepared sample solution was heated and shaken according to the following <Dissolution Conditions>. The sample solution after dissolution was placed in an autosampler heated to 160 °C without cooling. <Dissolution Conditions> (1) Stand still for 1 hour while heating to 150 °C (2) Shake for 2 hours while heating to 150 °C (3) Stand still for 30 minutes while heating to 150 °C Next, measurement was carried out according to the following <GPC Measurement Conditions>. <GPC Measurement Conditions> Differential refractometer (RI): Built-in to the apparatus Viscometer: PL-BV400 type Detector connection method: Connected in parallel Column: PLgel 20μm MIXED-A 300×7.5 mm (manufactured by Agilent Technologies) Column connection method: Connect two of the above columns in series Mobile phase: 1,2,4-trichlorobenzene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., with antioxidant 4,4'-thiobis(2-t-butyl-5-methylphenol) added at a concentration of 125 mg / L) Column temperature: 160℃ Detector temperature: 160℃ Sample solution temperature: 160℃ Sample injection port temperature: 160℃ Sample injection volume: 0.5 mL Flow rate: 1.0mL / min Furthermore, the column was calibrated using the universal calibration method with the following <sample for calibration curve creation>. <Sample for creating a calibration curve> Agilent EasiVial TM PS-H polystyrene (High MW) Agilent PL Polymer Standard (Part Number: PL2013-6001) Agilent PL Polymer Standard (Part Number: PL2014-9001) Next, the data obtained from measurements under the above conditions were analyzed using Agilent's CIRRUS GPC / SEC Software (version 3.4) to create a Mark-Houwink plot (a log-log graph plotting molecular weight MW on the x-axis and intrinsic viscosity IV on the y-axis). In this plot, the region where the molecular weight is lower than the peak-top molecular weight and where the log-log graph moves linearly was fitted using the following equation (F) to create a linear reference line shown by equation (G). Log 10 IV = a log 10 MW+log 10 C (Formula F) Log 10 IV=a linear Log 10 MW+log 10 C linear (Formula G) (In equations F and G, a and C are the variables during fitting, a linear and C linear (These are all constants obtained through fitting.) Next, using the following (Equation H) and (Equation I), the intrinsic viscosity IV of the sample at the same molecular weight is calculated. sample and the intrinsic viscosity of the linear reference line IV linear Using the values ​​of g' and g' z The result was calculated. g' = IV sample / IV linear (Formula H) g' z =Σ(Conc i ×MW i ×g' i ) / Σ(Conc i ×MW i (Formula I) (In formula I, Conc i is the solution concentration in the i-th fraction, MW i g' is the molecular weight in the i-th fraction. i (This is g' in the i-th fraction.) Finally, using the following formula (Equation J), z - mean contraction factor g z The result was calculated. z-mean contraction factor g z =g' z (1 / 0.75) (Formula J)

[0162] (Evaluation of stretchability) The following evaluation was performed using a Laboplast Mill Mixer (main unit model: 30C150, mixer type: R-60) and a simultaneous biaxial stretcher manufactured by Toyo Seiki Co., Ltd. First, 12 g of polyethylene powder, 0.4 g of Pentaerythritol tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (product name: ADEKA Stab AO-60G), an antioxidant manufactured by ADEKA, and 28 g of liquid paraffin (product name: P-350P), manufactured by MORESCO Co., Ltd., were thoroughly mixed in a resin container to obtain a mixture. Next, the above mixture was placed in a Laboplast Mill Mixer (main unit model: 30C150, mixer type: R-60) manufactured by Toyo Seiki Co., Ltd., set to a temperature of 200°C. After kneading at a rotation speed of 5 rpm for 10 minutes, the mixture was further kneaded at a rotation speed of 50 rpm for another 10 minutes to obtain polyethylene gel. This gel was formed into a sheet based on the <Gel Sheet Preparation Conditions> shown below. <Gel sheet manufacturing conditions> (1) The polyethylene gel described above was filled into a mold measuring 200 mm x 200 mm x 1 mm thick. (2) The mold is pressed in a press machine at a set temperature of 180°C at a rate of 1 kg / cm². 2 Preheat for 3 minutes, perform degassing 3 times, and reach 10 kg / cm³. 2 I pressed it for 2 minutes. (3) Using a cooling press machine at room temperature, 10 kg / cm 2 The mold was then cooled for 10 minutes. (4) Cut to 100mm x 100mm x 1mm thickness to obtain a gel sheet. The resulting gel sheets were stretched to a 7x7 ratio using a biaxial stretcher at 115°C to obtain stretched films. At this time, the stretchability was evaluated according to the following (stretchability evaluation criteria). (Stretchability evaluation criteria) ○ (Pass): No rupture of membranes × (Fail): Ruptured membrane present

[0163] (400cm -1 ~450cm -1 Absorption coefficient in Using a Fourier transform far-infrared spectrometer (manufactured by JASCO Corporation, model: VIR-F4000), the following method (terahertz measurement) was used to measure 400 cm². -1 ~450cm -1 The absorption coefficient was measured. First, polyethylene powder was formed into sheets using a heated automatic press (manufactured by Shinto Metal Industries Co., Ltd., model: SFA-37H) and a cooled manual press (manufactured by Oji Machinery Co., Ltd., model: J-37) based on the <pressing conditions> shown below. <Press Conditions> (1) 8 g of polyethylene powder was filled into a mold with dimensions of 50 mm × 50 mm × 2 mm in thickness. (2) The mold was preheated for 5 minutes at 5 kg / cm 2 using a heating automatic press machine set at a temperature of 210°C, and degassing operations were performed three times, followed by pressing for 25 minutes at 15 kg / cm 2 . (3) The mold was cooled for 10 minutes at 10 kg / cm 2 using a room-temperature cooling manual press machine to obtain a sheet. Next, the obtained sheet was punched into a disk with a diameter of 20 mm to obtain a measurement sample. For this measurement sample, measurements were performed according to the <terahertz measurement conditions> shown below using a Fourier transform type far-infrared spectrometer (manufactured by JASCO Corporation, model: VIR-F4000). <Terahertz measurement conditions> Wavenumber range: 50 - 600 cm -1 Measurement environment: In air, room temperature (25°C) Light source: Ceramic Beam diameter: Approximately 8 - 9 mm Holder hole diameter: 10 mm Furthermore, based on the incident light intensity I0 and the transmitted light intensity I obtained under the above measurement conditions, the absorption coefficient at each wavenumber was calculated according to the following (Equation K), and the absorption coefficient at 400 cm -1 ~450 cm -1 was calculated. α = -log 10 (I0 / I) / 0.4343x ··· (Equation K) α: Absorption coefficient [cm -1 I0: Intensity of the electromagnetic wave before incidence I: Intensity of the electromagnetic wave after incidence (transmitted light intensity) x: Sample thickness [cm]

[0164] ( 1 1H-NMR measurement) Using a nuclear magnetic resonance apparatus (manufactured by Bruker, product name: AvanceNEO600), it was determined by the method shown below. First, measurements were performed according to the following <NMR measurement conditions>. <NMR measurement conditions>​ Observation nucleus: 1 H Observation frequency: 600MHz Pulse program: zg30 Pulse waiting time: 1 sec Total number of times: 1024 Measurement temperature: 130℃ Chemical shift reference: 7.219 ppm (o-DCBz) Sample concentration: 1 wt% Sample tube: 5mmΦ Next, we examined the obtained data to check for the presence or absence of signals (peaks) in two regions: (1) 4.8 ppm to 5.0 ppm and (2) 5.6 ppm to 6.0 ppm.

[0165] (Aluminum content and silicon content) The elemental content of polyethylene powder was measured by high-frequency plasma mass spectrometry in accordance with JIS K0133. Sample preparation was performed by pressurized acid decomposition with nitric acid using a microwave decomposition apparatus (model ETHOSTC, manufactured by Milestone General Co., Ltd.). The aluminum and silicon content in the prepared samples were quantified using the internal standard method with ICP-MS (inductively coupled plasma mass spectrometer, model X series X7, manufactured by Thermo Fisher Scientific).

[0166] (Temperature of the peak top in the DSC curve during the second heating process) In the DSC measurement used to determine the above-mentioned (temperature difference between the peak top temperature and the peak convergence point in the DSC curve of the second heating process), the temperature indicating the peak top in the DSC curve of the second heating process (Tm2 top ) was sought.

[0167] (density) The density of the polyethylene powder was determined by the following methods (1) to (7). (1) Polyethylene powder was filled into a mold measuring 100 mm x 100 mm x 2 mm thick. (2) The mold is pressed in a press machine at a set temperature of 190°C at a rate of 10 kg / cm². 2 Preheat for 3 minutes, perform degassing 3 times, and reach 15 kg / cm². 2 I pressed it for 2 minutes. (3) The mold was cooled to room temperature using a cooling press to obtain a press sheet. (4) From the obtained press sheet, a section measuring 20 mm x 20 mm x 2 mm thick was cut out. (5) The cut sections were placed in a test tube and heated at 120°C for 1 hour under a nitrogen atmosphere. (6) After heating, the sections were cooled at 20°C for 1 hour to obtain molded samples for density measurement. (7) The density of the molded sample described above is measured in accordance with JIS K7112:1999 (Method D), and the obtained value is the density of polyethylene powder (kg / m³). 3 )

[0168] (Content (mol) of central metal M in transition metal compound component [B-1] and / or transition metal compound component [B-2] in the catalyst component, and the molar ratio (Al / M) of the content of central metal M (mol) to the content of Al (mol)) The elemental content in the catalyst components was measured using a microwave plasma atomic emission spectrometer (Agilent, model: 4210 MP-AES / G8007A). First, an acid-decomposed solution of the catalyst component was prepared based on the <decomposition conditions> shown below. <Decomposition conditions> (1) Under a nitrogen atmosphere, weigh out 100 mg to 500 mg of the catalyst component into a pressure vessel. (2) Add 10 mL of sulfuric acid (1+1) to the pressure vessel from (1) and stir for at least 1 hour. (3) Dilute the aqueous solution obtained in (2) to 100 mL. (4) Take 2 mL to 20 mL of the aqueous solution obtained in (3) and make up to 100 mL. The amount to take should be adjusted as appropriate according to the amount of luminescence measured later. Next, for the obtained acid-decomposed solution, based on the <MP-AES measurement conditions> shown below, using a microwave plasma atomic emission spectrometer (manufactured by Agilent, model: 4210 MP-AES / G8007A), by the external standard method, the content (mol) of the central metal M and the content (mol) of Al contained in the transition metal compound component [B-1] and / or the transition metal compound component [B-2] in the catalyst component were quantified, and their molar ratio (Al / M) was calculated. <MP-AES Measurement Conditions> Standard solution for instrument calibration: ICP-OES & MP-AES Wavecal: Al, As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Se, Sr, Zn (5 mg / L); K (50 mg / L) in 5% HNO3 Background correction: Auto Lead time: 3 s Observation position: 0 Nebulizer flow rate: M (0.5 - 1.0 L / min), Al (0.95 L / min) Number of measurement repetitions: 3 Pump speed: 15 rpm Sampling time: 15 s Stabilization time: 15 s Number of pixels: 3 Standard solution for calibration curve preparation: Standard solution for atomic absorption analysis corresponding to each element (manufactured by Kanto Chemical Co., Inc.) Calibration curve concentrations: 8 points of 0.5 mg / L, 1 mg / L, 2 mg / L, 5 mg / L, 10 mg / L, 20 mg / L, 50 mg / L, 100 mg / L

[0169] [Manufacture of Microporous Membrane and Evaluation of Characteristics] (Method for Manufacturing Microporous Membrane) First, in a resin container, 12 g of polyethylene powder of each example and comparative example, 0.4 g of Pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (product name: Adekastab AO-60G), an antioxidant manufactured by ADEKA Corporation, and 28 g of liquid paraffin (product name: P-350P) manufactured by MORESCO Corporation were thoroughly mixed to obtain a mixture. Next, the above mixture was placed in a Laboplast Mill Mixer (main unit model: 30C150, mixer type: R-60) manufactured by Toyo Seiki Co., Ltd., set to a temperature of 200°C. After kneading at a rotation speed of 5 rpm for 10 minutes, the mixture was further kneaded at a rotation speed of 50 rpm for another 10 minutes to obtain polyethylene gel. This gel was formed into a sheet based on the <Gel Sheet Preparation Conditions> shown below. <Gel sheet manufacturing conditions> (1) The polyethylene gel described above was filled into a mold measuring 200 mm x 200 mm x 1 mm thick. (2) The mold is pressed in a press machine at a set temperature of 180°C at a rate of 1 kg / cm². 2 Preheat for 3 minutes, perform degassing 3 times, and reach 10 kg / cm³. 2 I pressed it for 2 minutes. (3) Using a cooling press machine at room temperature, 10 kg / cm 2 The mold was then cooled for 10 minutes to obtain the gel sheet. The resulting gel sheets were then stretched 7x7 times using a biaxial stretcher at 115°C (for polyethylene with a viscosity-average molecular weight of 100,000 to less than 2,500,000) or 120°C (for polyethylene with a viscosity-average molecular weight of 2,500,000 to 4,000,000) to obtain stretched films. Subsequently, these stretched films were immersed in n-hexane for 20 minutes twice to extract and remove liquid paraffin, and then air-dried. Finally, they were heat-fixed at 125°C for 3 minutes to obtain microporous films. However, the stretching temperature and heat-fixing temperature were adjusted as appropriate for each microporous membrane within the specified temperature range.

[0170] (Evaluation of the heat resistance of microporous membranes) As an evaluation index for heat resistance, the thermal shrinkage rate of the microporous film at high temperatures was assessed. Specifically, from the microporous membrane obtained by the above-described [method for manufacturing a microporous membrane], eight 100mm x 50mm membranes were punched out from a 250mm x 250mm sheet, and they were left standing in an oven set to 140°C for 60 minutes. After heating and standing, the microporous membrane was cooled to room temperature for 15 minutes, and then its dimensions were measured. The thermal shrinkage rate (%) was calculated using the following formula. Then, the average of the eight measured values ​​was calculated, and the heat resistance was evaluated according to the following evaluation criteria. (Thermal contraction rate) = ((Thermal contraction rate in the long side direction) + (Thermal contraction rate in the short side direction)) / 2 (Thermal contraction coefficient in the direction of the longer side) = (1-D) 長辺140 / D 長辺23 ) × 100 (Thermal contraction coefficient in the short side direction) = (1-D) 短辺140 / D 短辺23 ) × 100 D 長辺140 Dimensions in the longest direction at 140℃ [mm] D 長辺23 Dimensions in the longest direction at 23℃ [mm] D 短辺140 Dimensions in the short-side direction at 140℃ [mm] D 短辺23 Dimensions in the short-side direction at 23℃ [mm] (Evaluation Criteria) ◎ (Good): Less than 40% ○ (Normal): 40% or more but less than 50% × (Bad): 50% or more

[0171] (Evaluation of the uniformity of microporous membranes) As an evaluation index for uniformity, the uniformity of the thickness of the microporous membrane was assessed. For the microporous membrane obtained by the above-described [Method for Manufacturing Microporous Membranes], eight 100mm x 50mm films were punched out from a 250mm x 250mm sheet, and the film thickness of each film was measured at 23°C using a microthickness measuring instrument (model: KBM) manufactured by Toyo Seiki Seisakusho Co., Ltd. Film thickness was measured at three locations on each punched film. Then, the standard deviation of the 24 measured values ​​was calculated, and uniformity was evaluated according to the following evaluation criteria. (Evaluation Criteria) ◎(Good): Less than 0.5μm ○ (Normal): 0.5 μm or more and less than 1 μm × (Bad): 1 μm or larger

[0172] (Evaluation of dimensional stability of microporous membranes) As an evaluation index for dimensional stability, the thermal shrinkage rate of the microporous membrane was assessed. Specifically, from the microporous membrane obtained by the above-described [method for manufacturing a microporous membrane], eight 100mm x 50mm membranes were punched out from a 250mm x 250mm sheet, and they were left standing in an oven set to 120°C for 60 minutes. After heating and standing, the microporous membrane was cooled to room temperature for 15 minutes, and then its dimensions were measured. The thermal shrinkage rate (%) was calculated using the following formula. Then, the average of the eight measurement points was calculated, and dimensional stability was evaluated according to the following evaluation criteria. (Thermal contraction rate) = ((Thermal contraction rate in the long side direction) + (Thermal contraction rate in the short side direction)) / 2 (Thermal contraction coefficient in the direction of the longer side) = (1-D) 長辺120 / D 長辺23 ) × 100 (Thermal contraction coefficient in the short side direction) = (1-D) 短辺120 / D 短辺23 ) × 100 D 長辺120 Dimensions in the longest direction at 120°C [mm] D 長辺23 Dimensions in the longest direction at 23℃ [mm] D 短辺120 Dimensions in the short-side direction at 120°C [mm] D 短辺23 Dimensions in the short-side direction at 23℃ [mm] (Evaluation Criteria) ◎ (Good): Less than 10% ○ (Normal): 10% or more but less than 20% × (Bad): 20% or more

[0173] (Evaluation of high heat resistance of microporous films) In the above-described (Method for Manufacturing Microporous Membranes), microporous membranes obtained by using 12g of high-density polyethylene "SH800" (trademark, manufactured by Asahi Kasei Corporation) with a viscosity-average molecular weight (Mv) of 300,000 instead of 12g of polyethylene powder in each example and comparative example, and microporous membranes obtained by using 8.4g of high-density polyethylene "SH800" (trademark, manufactured by Asahi Kasei Corporation) and 3.6g of polyethylene powder in each example and comparative example, instead of 12g of polyethylene powder in each example and comparative example, were evaluated using the method described in (Evaluation of Heat Resistance of Microporous Membranes) above. The rate of heat resistance was then evaluated according to the evaluation criteria below. (High heat resistance rate)=(1-S 添加後 / S 添加前 ) × 100 S 添加後 : Thermal shrinkage rate [%] of microporous membranes with added polyethylene powder in each example and comparative example. S 添加前 Thermal shrinkage rate [%] of a microporous membrane using only high-density polyethylene "SH800". (Evaluation Criteria) ◎ (Good): 20% or more ○ (Normal): 10% or more but less than 20% × (Bad): Less than 10%

[0174] [Preparation of catalyst components] (Preparation of inorganic solid particles [A]: (a-1) to (a-3)) Inorganic solid particles (a-1) to (a-3) were prepared according to (1) to (2) below. (Preparation of inorganic solid particles (a-1)) <(1) Synthesis of organomagnesium compound (A-1)> In an 8L stainless steel autoclave that has been thoroughly purged with nitrogen, 1 mol / L of Mg6(C4H9) 122,000 mL of hexane solution of AL(C2H5)3 (equivalent to 2,000 mmol of magnesium and aluminum) was charged into the autoclave. While stirring at 50°C, 146 mL of 5.47 mol / L n-butanol hexane solution was added dropwise through a feed line connected to the autoclave over 3 hours. After completion, the line was washed with 300 mL of hexane. Stirring was then continued at 50°C for 2 hours. After the reaction was complete, the mixture was cooled to room temperature and used as the starting material (A-1). Starting material (A-1) was an organomagnesium compound with a magnesium concentration of 0.704 mol / L.

[0175] <(2) Synthesis of inorganic solid particles (a-1)> In an 8L stainless steel autoclave that had been thoroughly purged with nitrogen, 1,000 mL of a hexane solution of 1 mol / L trichlorosilane was charged. At 65°C, 1,340 mL of a hexane solution of the organomagnesium compound (A-1) (equivalent to 943 mmol of magnesium) was added dropwise over 3 hours, and the reaction was continued at 65°C for 1 hour with stirring. After the reaction was complete, the supernatant was removed and washed four times with 1,800 mL of hexane to obtain inorganic solid particles (a-1) (magnesium chloride particles). Analysis of these particles revealed that the magnesium content per gram of solid was 7.5 mmol.

[0176] (Preparation of inorganic solid particles (a-2)) In an 8L stainless steel autoclave that had been thoroughly purged with nitrogen, 130g of heat-treated silica (manufactured by Fuji Silicia Co., Ltd. / product name: Q-6) and 2500mL of hexane were charged to obtain a slurry. While maintaining the obtained slurry at 20°C under stirring, 260mL of 1 mol / L methylaluminoxane (toluene solution, manufactured by Tosoh Finechem Co., Ltd.) was added, and the reaction was continued for 2 hours with stirring. After the reaction was complete, the supernatant was removed and washed four times with 1800mL of hexane to obtain inorganic solid particles (a-2).

[0177] (Preparation of inorganic solid particles (a-3)) In a 300 mL glass container that had been thoroughly nitrogen-purged, 10 g of heat-treated silica (Grace Davision, product name: Sylopol 952) and 100 mL of toluene were charged to obtain a slurry. While maintaining the obtained slurry at 80°C under stirring, 90 mL of 1 mol / L methylaluminoxane (toluene solution, Tosoh Finechem Co., Ltd.) was added, and the mixture was stirred for 1 hour. After stirring, the container temperature was cooled to room temperature, and 40 mL of 1 mol / L methylaluminoxane (toluene solution, Tosoh Finechem Co., Ltd.) was added, and the reaction was continued for another hour with stirring. After the reaction was complete, the supernatant was removed and washed four times with 100 mL of toluene to obtain inorganic solid particles (a-3).

[0178] (Preparation of transition metal compound component [B-2]: (b-1)) In a 3L glass container thoroughly purged with nitrogen, 200 mmol of [(Nt-butylamide)(tetramethyl-η5-cyclopentadienyl)dimethylsilane]titanium-1,3-pentadiene was dissolved in 1000 ml of Isopar E [Exxon Chemical], and 40 ml of 1 mol / L ethylbutylmagnesium (hexane solution) was added. Further hexane was added to adjust the titanium complex concentration to 0.08 mol / L, obtaining the transition metal compound component (b-1).

[0179] (Preparation of activator [C]:(c-1)) In a 500 mL glass container thoroughly purged with nitrogen, 17.8 g of bis(tulose alkyl hydride)methylammonium-tris(pentafluorophenyl)(4-hydroxyphenyl) borate was added to 156 mL of toluene and dissolved to obtain a 100 mM toluene solution of borate. While maintaining this toluene solution of borate at 25°C, 15.6 mL of 1 mol / L diethylaluminum ethoxide (hexane solution) was added, and further hexane was added to adjust the borate concentration in the toluene solution to 0.08 mol / L. Subsequently, the activator (c-1) was prepared by stirring at 25°C for 1 hour.

[0180] (Synthesis of organometallic compound component [D]:(d-1)) In an 8L stainless steel autoclave that has been thoroughly purged with nitrogen, 1 mol / L of Mg6(C4H9) 12 2,000 mL of hexane solution of Al(C2H5)3 (equivalent to 2,000 mmol of magnesium and aluminum) was charged, and while stirring at 80°C, 240 mL of hexane solution of 8.33 mol / L methylhydrodiene polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) was pumped in, and the reaction was continued at 80°C for 2 hours while stirring. After the reaction was complete, the mixture was cooled to room temperature and designated as organometallic compound component (d-1). The total concentration of magnesium and aluminum in organometallic compound component (d-1) was 0.786 mol / L.

[0181] (Example 1) (Preparation of catalyst component (A)) In a 50 mL glass container that has been thoroughly purged with nitrogen, 0.0011 mmol of bis(pentamethylcyclopentadienyl)titanium dichloride (Cp * 2TiCl2) was dissolved in 3 mL of toluene, and 1.42 mol / L of modified methylaluminoxane (MMAO, hexane solution, manufactured by Tosoh Finechem Co., Ltd.) was added. The mixture was reacted at 25°C for 1 hour to obtain the active species (A1). Next, 10 mL of a hexane slurry containing 0.44 g of the inorganic solid particles (a-1) was kept at 25°C, and the entire solution of the active species (A1) was added and the mixture was reacted for 1 hour. After the reaction was complete, the supernatant was removed and the mixture was washed four times with hexane to remove any unreacted raw material components. As a result of this reaction, a layer of the active species (A1) was formed on the surface of the inorganic solid particles (a-1). Furthermore, 1.4 mL of the transition metal compound component (b-1) and 1.4 mL of the activator (c-1) were added simultaneously and the mixture was reacted for 2 hours. After the reaction was complete, the supernatant was removed and the mixture was washed four times with hexane to remove any unreacted raw material components and obtain catalyst component (A). As described above, by supporting the transition metal compound component (b-1) and the activator (c-1) after supporting the active species (A1) (multiple-stage support), a two-layer structure was formed on the surface of the inorganic solid particles (a-1).

[0182] (Examples 2-9, Comparative Examples 2, 5, 6) (Preparation of catalyst components (B)~(H), (J), (M), (N), (E')) Except for changing the catalyst synthesis conditions as shown in Tables 1 and 2, catalyst components (B) to (H), (J), (M), (N), and (E') were prepared in the same manner as catalyst component (A).

[0183] (Example 10) (Preparation of catalyst component (O)) Catalyst component (O) was prepared in the same manner as catalyst component (A), except that the catalyst synthesis conditions were changed as shown in Table 1 and the reaction temperature in the pre-mixing step to obtain the active species (A1) was set to 90°C.

[0184] (Comparative Example 1) (Preparation of catalyst component (I)) In a 50 mL glass container thoroughly purged with nitrogen, 10 mL of toluene slurry containing 1 g of the inorganic solid particles (a-3) was kept at 40°C. 0.1 mmol of bis(n-butylcyclopentadienyl)zirconium dichloride (nBuCp2ZrCl2), pre-dissolved in toluene, was added and the mixture was reacted for 1 hour. Furthermore, 0.1 mmol of [(Nt-butylamide)(tetramethyl-η5-cyclopentadienyl)dimethylsilane]titanium dichloride (b-2), pre-dissolved in toluene, was added and the mixture was reacted for 1 hour. Finally, 0.2 mmol of N,N'-dimethylanilinium tetrakis(pentafluorophenyl)borate (c-2), pre-dissolved in toluene, was added and the mixture was reacted for 1 hour. After the reaction was complete, the supernatant was removed and unreacted raw material components were removed by washing four times with toluene. Toluene was then removed by vacuum drying to prepare catalyst component (I).

[0185] (Comparative Example 3) (Preparation of catalyst component (K)) To 1,970 mL of hexane slurry containing 110 g of the inorganic solid particles (a-1), 103 mL of a hexane solution of 1 mol / L titanium tetrachloride and 131 mL of organometallic compound component (d-1) were simultaneously added over 3 hours while stirring at 10°C. After the addition, the reaction was continued at 10°C for 1 hour. After the reaction was complete, the supernatant was removed and unreacted raw material components were removed by washing four times with hexane to prepare catalyst component (K).

[0186] (Comparative Example 4) (Preparation of catalyst component (L)) 1,600 mL of hexane was added to an 8 L stainless steel autoclave that had been thoroughly purged with nitrogen. 800 mL of a 1 mol / L titanium tetrachloride hexane solution and 1017 mL of organometallic compound component (d-1) were simultaneously added over 2 hours while stirring at 40°C. After the addition, the temperature was slowly raised and the reaction was continued at 40°C for 1 hour. After the reaction was complete, 1,600 mL of the supernatant was removed and the catalyst component (L) was prepared by washing four times with 1,600 mL of hexane.

[0187] [Table 1]

[0188] [Table 2]

[0189] In Tables 1 and 2, a-1 to a-3 represent the inorganic solid particles (a-1) to (a-3) prepared above, respectively; b-1 represents the transition metal compound component (b-1) prepared above; b-2 represents [(Nt-butylamide)(tetramethyl-η5-cyclopentadienyl)dimethylsilane]titanium dichloride; c-1 represents the activator (c-1) prepared above; c-2 represents N,N'-dimethylanilinium tetrakis(pentafluorophenyl)borate; d-1 represents the synthesized organometallic compound component (d-1); Cp *2TiCl2 represents bis(pentamethylcyclopentadienyl)titanium dichloride, Cp2TiCl2 represents bis(cyclopentadienyl)titanium dichloride, nBuCp2ZrCl2 represents bis(n-butylcyclopentadienyl)zirconium dichloride, Cp * 2ZrCl2 represents bis(pentamethylcyclopentadienyl)zirconium dichloride, TiCl4 represents titanium tetrachloride, Ti(OBu)4 represents titanium(IV) tetrabutoxide (monomer), EtAlCl2 represents ethyl aluminum dichloride, Et2AlCl represents diethyl aluminum chloride, MMAO represents modified methyl aluminoxane, and MAO represents methyl aluminoxane.

[0190] [Manufacturing of polyethylene powder and microporous membranes] (Example 11) <Polymerization of polyethylene powder (A)> Polymerization of polyethylene powder was carried out using a 1.5 L stainless steel autoclave polymerization reactor that was thoroughly purged with nitrogen, in the manner described below. First, 800 mL of hexane was charged as a solvent into a polymerization reactor heated to 60°C, and 0.4 mmol of organometallic compound component (d-1) was added as an impurity scavenger. Next, ethylene was added to bring the internal pressure to 0.65 MPa, and 1.25 μmol of the catalyst component (A) in terms of Ti was added. Furthermore, 0.5 mL of hydrogen was added for every 1 L of ethylene consumed. Polymerization was carried out for 30 minutes while stirring at a stirring speed of 1200 rpm, maintaining an internal pressure of 0.65 MPa and an internal temperature of 60°C. After polymerization was complete, the reaction mixture (polymer slurry) was removed from the polymerization reactor, and the catalyst was deactivated with methanol. Subsequently, the reaction mixture was filtered, washed, and air-dried to obtain polyethylene powder (A). The polymerization activity in the polymerization reactor was 3,500 g per 1 g of catalyst. Table 5 shows the results of the various evaluations conducted on polyethylene powder (A) and the microporous membrane made from polyethylene powder (A) produced by the above-described [Method for Manufacturing Microporous Membranes].

[0191] (Examples 12-20 and Comparative Examples 7, 8, 11, 12) Except for changing the polymerization conditions as shown in Tables 3 and 4, polyethylene powder and its microporous membrane were produced in the same manner as in Example 11, and the various evaluations described above were carried out. The results are shown in Tables 5 and 6. In Example 15 and Comparative Example 12, 1-butene was copolymerized at 0.05 mol% as the comonomer.

[0192] (Comparative Example 9) Hexane, ethylene, hydrogen, and catalyst were continuously supplied to a 300 L vessel-type polymerization reactor equipped with a full-zone, baffle-less stirring blade. The partial pressure of polymerized ethylene was set to 0.5 MPa. The polymerization temperature was maintained at 75°C by jacket cooling. Hexane was supplied from the bottom of the polymerization reactor at a rate of 40 L / hour, with an average residence time of 3 hours. Before supplying the catalyst to the polymerization reactor, 1 g of catalyst component (K) was mixed with 2 mmol of 1 M ethylaluminum dichloride, and the supernatant was then decanted and replaced with hexane. This pretreatment was performed three times before the catalyst was used. 1 g of the pretreated catalyst component (K) was mixed with 20 mmol of triisobutylaluminum as an impurity scavenger in a buffer tank before polymerization supply. The mixed catalyst component (K) was added to the polymerization reactor at a rate of 0.2 g / hour. Ethylene and hydrogen were introduced into the gas phase, and hydrogen was continuously supplied by pump so that the hydrogen concentration relative to the ethylene in the gas phase was 5 mol%. Furthermore, the stirring speed was set to 230 rpm. To maintain a constant level in the polymerization reactor, the mixture was continuously transferred to a flash drum at a pressure of 0.05 MPa and a temperature of 70°C to separate unreacted ethylene and hydrogen. Next, the polymerization slurry was continuously fed into a centrifuge to maintain a constant level in the polymerization reactor, separating the polyethylene powder from the other solvents and other components. The separated polyethylene powder was dried at 78°C while blowing with nitrogen. During this drying process, steam was sprayed onto the polymerized powder to deactivate the catalyst and co-catalysts. 1,000 ppm of calcium stearate (Dainichi Chemical Co., Ltd., C60) was added to the obtained polyethylene powder and homogeneously mixed using a Henschel mixer. The obtained polyethylene powder was sieved using a 425 μm mesh sieve to remove any material that did not pass through the sieve, thereby obtaining polyethylene powder (K). The polymerization activity in the polymerization reactor was 20,000 g per 1 g of catalyst. Table 6 shows the results of the various evaluations conducted on polyethylene powder (K) and the microporous membrane made from polyethylene powder (K) produced by the above-described [Method for Manufacturing Microporous Membranes].

[0193] (Comparative Example 10) Hexane, ethylene, hydrogen, and catalyst were continuously supplied to a 300 L vessel-type polymerization reactor equipped with a stirrer. The polymerization pressure was 0.35 MPa. The polymerization temperature was maintained at 75°C by jacket cooling. Hexane was supplied from the bottom of the polymerization reactor at a rate of 40 L / hour, and the average residence time was 3 hours. Catalyst component (L) was used as the catalyst, and triisobutylaluminum was used as an impurity scavenger. Triisobutylaluminum was added to the polymerization reactor at a rate of 10 mmol / h. Catalyst component (L) was supplied at a rate of 0.2 g / hour. Hydrogen was continuously supplied by pump to achieve a gas phase concentration of 2000 ppm. The stirring speed was 230 rpm. A 100 mmol / L hexane solution of n-butanol was supplied so that the amount of n-butanol was 1 ppm / h relative to the polymerization rate (production rate) of 10 kg / h to obtain a polymerization slurry. The obtained polymerization slurry was sent to a centrifuge to separate the polyethylene powder from the other solvents, etc. Then, the polyethylene powder was contacted with methanol at 60°C while stirring for 1 hour. The polymerization slurry containing polyethylene powder and methanol was sent to a centrifuge to separate the polyethylene powder from the other solvents, etc. The separated polyethylene powder was dried at 70°C under nitrogen blowing. The resulting polyethylene powder was then sieved using a 425 μm mesh sieve to remove any material that did not pass through the sieve, thereby obtaining polyethylene powder (L). The polymerization activity in the polymerization reactor was 30,000 g per 1 g of catalyst. Table 6 shows the results of the various evaluations conducted on polyethylene powder (L) and the microporous membrane made from polyethylene powder (L) produced by the above-described [Method for Manufacturing Microporous Membranes].

[0194] [Table 3]

[0195] [Table 4] In Tables 3 and 4, d-1 represents the synthesized organometallic compound component (d-1) described above, Et3Al represents triethylaluminum, and iBu3Al represents triisobutylaluminum.

[0196] [Table 5]

[0197] [Table 6]

[0198] This application is based on Japanese Patent Application No. 2022-059266 filed on March 31, 2022, the contents of which are incorporated herein by reference. [Industrial applicability]

[0199] The polyethylene powder of the present invention, for example, when used in a microporous membrane, exhibits excellent heat resistance, membrane uniformity, dimensional stability, and high heat resistance, making it suitable for industrial applications.

Claims

1. The viscosity-average molecular weight is between 100,000 and 4,000,000. The crystal thickness parameter obtained from measurements using differential scanning calorimeter (DSC) is between 5°C and 9°C. z-mean contraction factor g is measured by a gel permeation chromatography (GPC) analyzer that combines a differential refractometer and a viscodetector. z Polyethylene powder in which the value is between 0.600 and 1.

2. Using a differential scanning calorimeter (DSC), in the DSC curve of the second heating process obtained by the measurement shown in <Measurement Conditions> below, the peak top temperature (Tm²) top ) is between 135°C and 140°C, <Measurement conditions> (1) Leave standing at 50°C for 1 min (2) Heating from 50°C to 180°C at a rate of 10°C / min (first heating process) (3) Leave standing at 180°C for 5 minutes. (4) Cool from 180°C to 50°C at 10°C / min (5) Leave standing at 50°C for 5 minutes. (6) Heating from 50°C to 180°C at a rate of 10°C / min (second heating process) The polyethylene powder according to claim 1, wherein the crystal thickness parameter is 6.7°C or higher and 9.0°C or lower.

3. Polyethylene powder according to claim 1 or 2, which is stretchable under the following conditions; (Stretching conditions) A gel sheet measuring 100 mm x 100 mm x 1 mm thick, consisting of 30% by mass polyethylene powder and 70% by mass liquid paraffin, is stretched to 7 x 7 times its original size at 115°C.

4. In terahertz measurement, 400 cm -1 ~450cm -1 The polyethylene powder according to claim 1 or 2, wherein the absorption coefficient in is 1.0 or more and 4.0 or less.

5. 1 The polyethylene powder according to claim 1 or 2, wherein, in 1H-NMR measurement, no peaks are present in the region shown below. (1) 4.8ppm to 5.0ppm (2) 5.6ppm to 6.0ppm

6. The polyethylene powder according to claim 1 or 2, wherein the aluminum content is 0 ppm or more and 50 ppm or less.

7. The polyethylene powder according to claim 1 or 2, wherein the silicon content is 0 ppm or more and 30 ppm or less.

8. The polyethylene powder according to claim 1, wherein, in differential scanning calorimeter (DSC) measurements, the peak top temperature in the DSC curve of the second heating process is 130°C or higher and 140°C or lower.

9. Density is 920 kg / m³ 3 More than 960kg / m 3 The polyethylene powder according to claim 1 or 2, which is as follows:

10. A polyethylene powder according to claim 1 or 2, for use as a battery separator.

11. A method for producing polyethylene powder, A first supporting reaction step involves reacting inorganic solid particles [A] with a transition metal compound [B-1] and / or a transition metal compound component [B-2] and an activator [C] and / or an organometallic compound component [D], The process includes a second supporting reaction step in which the particles obtained in the first supporting reaction step are reacted with a transition metal compound component [B-1] and / or a transition metal compound component [B-2] and an activator [C] and / or an organometallic compound component [D]. The transition metal compound [B-1] is a compound represented by the following (Formula 3), the transition metal compound [B-2] is a compound represented by the following (Formula 4), the activator [C] is a compound represented by the following (Formula 5) or (Formula 6), the organometallic compound component [D] is a compound containing at least one metal selected from the group consisting of Groups 1, 2, 12 and 13 of the periodic table, and the inorganic solid particles [A] are porous polymer materials or inorganic solid particles containing at least one element selected from the group consisting of Groups 2 to 4, 13 and 14 of the periodic table. A step of obtaining an olefin polymerization catalyst by a method for producing an olefin polymerization catalyst that satisfies the following <Condition 1> and / or <Condition 2>, The process includes obtaining polyethylene powder by polymerizing ethylene or ethylene with other comonomers using the olefin polymerization catalyst, A method for producing polyethylene powder, wherein the polyethylene powder has a viscosity-average molecular weight of 100,000 or more and 4,000,000 or less, a crystal thickness parameter obtained from measurement using a differential scanning calorimeter (DSC) is 5°C or more and 9°C or less, and the value of the z-average contraction factor gz measured by a gel permeation chromatography (GPC) measuring device combining a differential refractometer and a viscodetector is 0.600 or more and 1 or less. <Condition 1> The first support reaction step includes a pre-mixing step in which a transition metal compound [B-1] and / or a transition metal compound component [B-2] are reacted with an activator [C] and / or an organometallic compound component [D], and a step in which the mixture obtained in the pre-mixing step is reacted with inorganic solid particles [A]. <Condition 2> In the first supporting reaction step, the molar ratio (([C] + [D]) / [B]) of the activator [C] and organometallic compound component [D] to the molar amount [B] of the transition metal compound component [B-1] and / or the transition metal compound component [B-2] is 1 or more and 60 or less. L 1 j W k M 1 X 1 p X 2 q ... (Formula 3) (In the formula, L 1 Each independently represents an η-bonded cyclic anionic ligand selected from the group consisting of a cyclopentadienyl group, an indenyl group, a tetrahydroindenyl group, a fluorenyl group, a tetrahydrofluorenyl group, and an octahydrofluorenyl group, and the ligand may have 1 to 8 substituents, each of which independently has up to 20 nonhydrogen atoms selected from the group consisting of a hydrocarbon group having 1 to 20 carbon atoms, a halogen atom, a halogen-substituted hydrocarbon group having 1 to 12 carbon atoms, an aminohydrocarbyl group having 1 to 12 carbon atoms, a hydrocarbyloxy group having 1 to 12 carbon atoms, a dihydrocarbylamino group having 1 to 12 carbon atoms, a hydrocarbylphosphono group having 1 to 12 carbon atoms, a silyl group, an aminosilyl group, a hydrocarbyloxysilyl group having 1 to 12 carbon atoms, and a halosilyl group. M 1 This represents a transition metal selected from the transition metal group belonging to Group 4 of the periodic table with formal oxidation states of +2, +3, or +4, and which is η5-bonded to at least one ligand L. W represents a divalent substituent having up to 50 non-hydrogen atoms, which is bonded to L and M with a valency of 1 each, thereby cooperating with L and M to form a metallocycle. X 1 Each of these independently represents an anionic σ-bond ligand having up to 60 non-hydrogen atoms, selected from the group consisting of a monovalent anionic σ-bond ligand, a divalent anionic σ-bond ligand that bonds to M in a divalent state, and a divalent anionic σ-bond ligand that bonds to L and M with a 1-valent state each. X 2 Each of these independently represents a neutral Lewis base coordinating compound having up to 40 non-hydrogen atoms. j is 1 or 2, however when j is 2, in some cases two ligands L are bonded to each other via a divalent group having up to 20 nonhydrogen atoms, the divalent group being selected from the group consisting of a C1-C20 hydrocarbadiyl group, a C1-C12 halohydrocarbadiyl group, a C1-C12 hydrocarbyleneoxy group, a C1-C12 hydrocarbyleneamino group, a silanediyl group, a halosilanediyl group, and a silyleneamino group, k is 0 or 1, and p is 0, 1 or 2, however X 1 If is a monovalent anionic σ-bond ligand, or a divalent anionic σ-bond ligand bonded to L and M, then p is an integer less than or equal to 1 the formal oxidation number of M, and X 1 If is a divalent anionic σ-bond type ligand bonded only to M, then p is an integer less than or equal to (j+1) the formal oxidation number of M, and q is 0, 1, or 2. 【Chemistry 1】 (In the formula, M 2 This represents a transition metal selected from the group consisting of titanium, zirconium, and hafnium, whose formal oxidation number is +2, +3, or +4. R 5 Each of these independently represents a substituent having 1 to 20 non-hydrogen atoms, selected from the group consisting of hydrogen atoms, hydrocarbon groups having 1 to 8 carbon atoms, silyl groups, germyl groups, cyano groups, halogen atoms, and composite groups thereof, provided that the substituent R 5 When is a hydrocarbon group having 1 to 8 carbon atoms, a silyl group, or a gelmyl group, there may be two adjacent substituents R 5 These two groups bond to each other to form a divalent group, thereby the two adjacent substituents R 5 The bonds between the two carbon atoms of the cyclopentadienyl rings bonded to each of them work in cooperation to form rings, X 3 Each of these independently represents a substituent having 1 to 20 nonhydrogen atoms, selected from the group consisting of halides, hydrocarbon groups having 1 to 20 carbon atoms, hydrocarbyloxy groups having 1 to 18 carbon atoms, hydrocarbylamino groups having 1 to 18 carbon atoms, silyl groups, hydrocarbylamide groups having 1 to 18 carbon atoms, hydrocarbylphosphine groups having 1 to 18 carbon atoms, hydrocarbyl sulfide groups having 1 to 18 carbon atoms, and composite groups thereof, provided that, in some cases, two substituents X 3 These groups cooperate to form a neutral conjugated diene or divalent group having 4 to 30 carbon atoms. Y 1 -O-, -S-, -NR 6 - or - PR 6 - represents, however, R 6 This represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, a hydrocarbyloxy group having 1 to 8 carbon atoms, a silyl group, an alkyl halogen group having 1 to 8 carbon atoms, an aryl halogen group having 6 to 20 carbon atoms, or a composite group thereof. Z 1 is SiR 6 2 CR 6 2 , SiR 6 2 SiR 6 2 CR 6 2 CR 6 2 CR 6 =CR 6 CR 6 2 SiR 6 2 Or GeR 6 2 This represents, however, R 6 As defined above, n is 1, 2, or 3. (C-1): [L] 2 -H] d+ [M] 3 r Q s ] d- ... (Form 5) (In the formula, [L 2 -H] d+ It is a proton-donating Brønsted acid, L 2 [M] is a neutral Lewis base. 3 r Q s ] d- M is a compatible non-coordinating anion. 3 Q is a metal or metalloid selected from groups 5 through 15 of the periodic table, and each Q is independently a hydride, dialkylamide group, halide, alkoxide group, alliloxide group, hydrocarbon group, or substituted hydrocarbon group with up to 20 carbon atoms, and there is no more than one halide Q. Also, r is an integer from 1 to 7, s is an integer from 2 to 14, and d is an integer from 1 to 7, with s - r = d. (C-2): -(M) 4 R 7 t-2 -O) u —・・・(Form 6) (In the formula, M 4 R is a metal or metalloid from groups 13 to 15 of the periodic table. 7 Each of these is independently a hydrocarbon group having 1 to 12 carbon atoms or a substituted hydrocarbon group, and t is a metal M 4 (This is the valence of , where u is an integer greater than or equal to 2.)

12. The method for producing polyethylene powder according to claim 11, wherein the inorganic solid particles [A] are magnesium chloride particles.

13. A catalyst for polyethylene powder polymerization, It comprises inorganic solid particles [A], a transition metal compound component [B-1] and / or a transition metal compound component [B-2], and an activator [C] and / or an organometallic compound component [D]. The transition metal compound [B-1] is a compound represented by the following (Formula 3), the transition metal compound [B-2] is a compound represented by the following (Formula 4), the activator [C] is a compound represented by the following (Formula 5) or (Formula 6), the organometallic compound component [D] is a compound containing at least one metal selected from the group consisting of Groups 1, 2, 12 and 13 of the periodic table, and the inorganic solid particles [A] are porous polymer materials or inorganic solid particles containing at least one element selected from the group consisting of Groups 2 to 4, 13 and 14 of the periodic table. The content (mol) of central metal M in the transition metal compound component [B-1] and / or the transition metal compound component [B-2] is 20 μmol or more and 1000 μmol or less, and the molar ratio (Al / M) of the content (mol) of central metal M to the content (mol) of Al is 1 or more and 30 or less. A polyethylene powder polymerization catalyst wherein the polyethylene powder has a viscosity-average molecular weight of 100,000 or more and 4,000,000 or less, a crystal thickness parameter obtained from measurement using a differential scanning calorimeter (DSC) is 5°C or more and 9°C or less, and the value of the z-average shrinkage factor gz measured by a gel permeation chromatography (GPC) measuring device combining a differential refractometer and a viscodetector is 0.600 or more and 1 or less. L 1 j W k M 1 X 1 p X 2 q ... (Formula 3) (In the formula, L 1 Each independently represents an η-bonded cyclic anionic ligand selected from the group consisting of a cyclopentadienyl group, an indenyl group, a tetrahydroindenyl group, a fluorenyl group, a tetrahydrofluorenyl group, and an octahydrofluorenyl group, and the ligand may have 1 to 8 substituents, each of which independently has up to 20 nonhydrogen atoms selected from the group consisting of a hydrocarbon group having 1 to 20 carbon atoms, a halogen atom, a halogen-substituted hydrocarbon group having 1 to 12 carbon atoms, an aminohydrocarbyl group having 1 to 12 carbon atoms, a hydrocarbyloxy group having 1 to 12 carbon atoms, a dihydrocarbylamino group having 1 to 12 carbon atoms, a hydrocarbylphosphono group having 1 to 12 carbon atoms, a silyl group, an aminosilyl group, a hydrocarbyloxysilyl group having 1 to 12 carbon atoms, and a halosilyl group. M 1 This represents a transition metal selected from the transition metal group belonging to Group 4 of the periodic table with formal oxidation states of +2, +3, or +4, and which is η5-bonded to at least one ligand L. W represents a divalent substituent having up to 50 non-hydrogen atoms, which is bonded to L and M with a valency of 1 each, thereby cooperating with L and M to form a metallocycle. X 1 Each of these independently represents an anionic σ-bond ligand having up to 60 non-hydrogen atoms, selected from the group consisting of a monovalent anionic σ-bond ligand, a divalent anionic σ-bond ligand that bonds to M in a divalent state, and a divalent anionic σ-bond ligand that bonds to L and M with a 1-valent state each. X 2 Each of these independently represents a neutral Lewis base coordinating compound having up to 40 non-hydrogen atoms. j is 1 or 2, however when j is 2, in some cases two ligands L are bonded to each other via a divalent group having up to 20 nonhydrogen atoms, the divalent group being selected from the group consisting of a C1-C20 hydrocarbadiyl group, a C1-C12 halohydrocarbadiyl group, a C1-C12 hydrocarbyleneoxy group, a C1-C12 hydrocarbyleneamino group, a silanediyl group, a halosilanediyl group, and a silyleneamino group, k is 0 or 1, and p is 0, 1 or 2, however X 1 If is a monovalent anionic σ-bond ligand, or a divalent anionic σ-bond ligand bonded to L and M, then p is an integer less than or equal to 1 the formal oxidation number of M, and X 1 If is a divalent anionic σ-bond type ligand bonded only to M, then p is an integer less than or equal to (j+1) the formal oxidation number of M, and q is 0, 1, or 2. 【Chemistry 2】 (wherein, M 2 represents a transition metal selected from the group consisting of titanium, zirconium and hafnium, and having a formal oxidation number of +2, +3 or +4; R 5 Each of these independently represents a substituent having 1 to 20 non-hydrogen atoms, selected from the group consisting of hydrogen atoms, hydrocarbon groups having 1 to 8 carbon atoms, silyl groups, germyl groups, cyano groups, halogen atoms, and composite groups thereof, provided that the substituent R 5 When is a hydrocarbon group having 1 to 8 carbon atoms, a silyl group, or a gelmyl group, there may be two adjacent substituents R 5 These two groups bond to each other to form a divalent group, thereby the two adjacent substituents R 5 The bonds between the two carbon atoms of the cyclopentadienyl rings bonded to each of them work in cooperation to form rings, X 3 Each of these independently represents a substituent having 1 to 20 nonhydrogen atoms, selected from the group consisting of halides, hydrocarbon groups having 1 to 20 carbon atoms, hydrocarbyloxy groups having 1 to 18 carbon atoms, hydrocarbylamino groups having 1 to 18 carbon atoms, silyl groups, hydrocarbylamide groups having 1 to 18 carbon atoms, hydrocarbylphosphine groups having 1 to 18 carbon atoms, hydrocarbyl sulfide groups having 1 to 18 carbon atoms, and composite groups thereof, provided that, in some cases, two substituents X 3 These groups cooperate to form a neutral conjugated diene or divalent group having 4 to 30 carbon atoms. Y 1 represents -O-, -S-, -NR 6 -, or -PR 6 -, provided that R 6 represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, a hydrocarbyloxy group having 1 to 8 carbon atoms, a silyl group, a halogenated alkyl group having 1 to 8 carbon atoms, a halogenated aryl group having 6 to 20 carbon atoms, or a composite group thereof, Z 1 is SiR 6 2 CR 6 2 , SiR 6 2 SiR 6 2 CR 6 2 CR 6 2 CR 6 =CR 6 CR 6 2 SiR 6 2 Or GeR 6 2 This represents, however, R 6 As defined above, n is 1, 2, or 3. (C-1): [L] 2 -H] d+ [M] 3 r Q s ] d- ... (Form 5) (In the formula, [L 2 -H] d+ It is a proton-donating Brønsted acid, L 2 [M] is a neutral Lewis base. 3 r Q s ] d- M is a compatible non-coordinating anion. 3 Q is a metal or metalloid selected from groups 5 through 15 of the periodic table, and each Q is independently a hydride, dialkylamide group, halide, alkoxide group, alliloxide group, hydrocarbon group, or substituted hydrocarbon group with up to 20 carbon atoms, and there is no more than one halide Q. Also, r is an integer from 1 to 7, s is an integer from 2 to 14, and d is an integer from 1 to 7, with s - r = d. (C-2): -(M) 4 R 7 t-2 -O) u —・・・(Form 6) (In the formula, M 4 R is a metal or metalloid from groups 13 to 15 of the periodic table. 7 Each of these is independently a hydrocarbon group having 1 to 12 carbon atoms or a substituted hydrocarbon group, and t is a metal M 4 (This is the valence of , where u is an integer greater than or equal to 2.)

14. The catalyst for polyethylene powder polymerization according to claim 13, wherein the inorganic solid particles [A] are magnesium chloride particles.

15. A method for producing polyethylene powder, comprising the step of polymerizing an olefin using the polyethylene powder polymerization catalyst described in claim 13 or 14.

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