Polyethylene resin composition

Abstract

To provide a polyethylene resin composition which has excellent strength and fuse performance when be worked to a separator of a battery, can shorten time from start of fuse performance to completion of the fuse performance, and is less in film defects and film thickness unevenness.SOLUTION: A polyethylene resin composition has Mw of 100,000 or more and 1,000,000 or less and Mw / Mn of 2 or more and 18 or less. When an extract component obtained by temperature rise liberation fractionation according to a predetermined condition "temperature rise liberation fractionation of polyethylene resin composition" is measured by cross fractionation chromatography measurement according to a predetermined condition "CFC measurement condition of extract component" in a solution using o-dichlorobenzene as a solvent, an integral elution amount at 40°C or higher and lower than 90°C is 10 mass% or more and less than 70 mass% with respect to the total elution amount, an integral elution amount at 90°C or higher and 95°C or lower is 10 mass% or more with respect to the total elution amount, and a temperature at the maximum elution amount is 88°C or higher and 100°C or lower.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a polyethylene resin composition. [Background technology]

[0002] Polyethylene is used in a variety of applications, such as sheets, films, and molded articles, and one of its important applications is as a raw material for battery separators (hereinafter sometimes referred to as separator raw material). A separator is a porous membrane used mainly to separate the positive electrode and the negative electrode inside a battery and to allow only ions to pass through. Other uses of the separator include use as a constituent member of a battery to ensure that the battery has sufficient strength for practical use, and use as a member that performs a shutdown (hereinafter also referred to as a "fuse") function to prevent runaway battery reactions when the temperature inside the battery becomes high.

[0003] The polyethylene used as a separator raw material is typically polyethylene with a relatively high molecular weight and high density compared to the general-purpose polyethylene used for sheets, films, molded articles, etc., and is commercially available in powder form. The reason why polyethylene used as a separator raw material has a high molecular weight and a high density is to ensure the strength of the separator. The reason why polyethylene used as a separator raw material is in powder form is that its high molecular weight makes it difficult to process, making it difficult to pelletize, and furthermore, the powder form is more easily processable.

[0004] Much research and development has been conducted to obtain superior separators, and one of the challenges is controlling thermal shrinkage during the membrane production process. Generally, the manufacturing process of a microporous membrane or the like includes a stretching step. The stretching step is usually followed by an annealing step (hereinafter sometimes referred to as "heat setting") to relax the molecular orientation and suppress thermal shrinkage after stretching and in the usage environment. In this heat setting step, components that are prone to molecular motion even at low temperatures (hereinafter sometimes referred to as "amorphous components") undergo molecular motion, thereby relaxing the molecular orientation. However, high-density polyethylene with a high degree of crystallinity has a low proportion of the amorphous component, and therefore, even when subjected to a heat setting step, the molecular orientation may not be sufficiently relaxed, and there is a risk that the thickness of the microporous membrane may become unstable due to heat shrinkage or the like.

[0005] As a method for solving such problems, a method is known in which the average molecular weight and molecular weight distribution of polyethylene are adjusted to ensure appropriate molecular mobility at low temperatures and to efficiently carry out the annealing step (thermal setting step) (see, for example, Patent Document 1).

[0006] Furthermore, when the average molecular weight of polyethylene is increased in order to increase the strength of the separator, the processability of the separator deteriorates, which is a trade-off relationship that must be addressed. As a method for solving such problems, a method is known in which the average molecular weight and molecular weight distribution of polyethylene are appropriately adjusted to obtain a molded product with excellent mechanical strength and to ensure excellent solubility or meltability, thereby improving processability (see, for example, Patent Document 2).In addition, as a method for solving the same problems, a method is known in which processing conditions for polyethylene powder (such as the amount of solvent used, the kneading temperature, and the kneading torque) are controlled (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-118515 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-118535 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-235926 Summary of the Invention [Problem to be solved by the invention]

[0008] However, while the techniques described in Patent Documents 1 to 3 have the effect of ensuring the strength of the membrane and controlling thermal shrinkage, they do not consider further improvements in fuse performance, i.e., the fuse function under low temperature conditions, or the function of shortening the time from fuse initiation to completion, or achieving both of these functions, and there is an increasing demand for separators that have such functions.

[0009] Therefore, an object of the present invention is to provide a polyethylene resin composition that, when processed into a separator, has excellent strength and fuse performance, the time from the start to the completion of fusing is short, and further, it is possible to reduce film defects and film thickness unevenness. [Means for solving the problem]

[0010] As a result of intensive research conducted by the present inventors in order to solve the problems of the prior art described above, the present inventors have found that the above problems can be solved by specifying a polyethylene resin composition having a predetermined weight-average molecular weight and molecular weight distribution, wherein, when an extract component obtained by temperature-elevation free fractionation of the polyethylene resin composition is measured by cross-fractionation chromatography (hereinafter referred to as "CFC") under predetermined conditions using o-dichlorobenzene as a solvent, the integrated elution amount at 40°C or higher and lower than 90°C is within a predetermined amount (mass%) relative to the total elution amount, the integrated elution amount at 90°C or higher and 95°C or lower is a predetermined amount or more relative to the total elution amount, and the temperature at which the elution amount becomes maximum is within a predetermined temperature range, thereby completing the present invention. That is, the present invention is as follows.

[0011] [1] The weight average molecular weight (Mw) is 250,000 or more and 1,000,000 or less, A polyethylene resin composition having a molecular weight distribution (Mw / Mn) of 2 or more and 18 or less, The polyethylene resin composition comprises Compositions comprising ethylene homopolymers and copolymers of ethylene and comonomers; Or a composition containing two types of copolymers of ethylene and a comonomer, the comonomer is an α-olefin having 3 to 20 carbon atoms, According to the "Temperature-Increased Free Fractionation Conditions for Polyethylene Resin Composition" below (Condition 1), The extracted components obtained by the up-stream fractionation were dissolved in o-dichlorobenzene as a solvent. The solution was subjected to cross-fractionation chromatography according to the "CFC measurement conditions for extracted components" below (Condition 1). When measuring the graph, The integrated elution amount at temperatures between 40°C and 90°C is 20% by mass or more and less than 60% by mass of the total elution amount. the law of nature, the integrated elution amount at 90°C or higher and 95°C or lower is 10% by mass or higher of the total elution amount, The temperature at which the maximum amount of elution occurs is between 88°C and 100°C. The polyethylene resin composition was subjected to the following (Condition 1) "Temperature of polyethylene resin composition The extracted components obtained by temperature-elevated free fractionation according to the "temperature-elevated free fractionation conditions" are The comonomer content when measured by MR is 0.6 mol% or more. Polyethylene resin composition. (Condition 1) "Temperature-increasing free fractionation conditions for polyethylene resin compositions" (1) Solvent: Toluene (2) Soxhlet extraction time: 6 hours (3) Method for collecting the components extracted into toluene solvent: Add methanol to the toluene solvent. The extract is then filtered off with suction to obtain the extract. "CFC measurement conditions for extracted components" (1) The o-dichlorobenzene solution of the extracted components is kept at 140°C for 120 minutes. (2) After cooling the o-dichlorobenzene solution of the extracted components to 40°C at a rate of 0.5°C / min, Hold for 20 minutes. (3) Using the temperature program shown in (a) to (d) below, the column temperature was increased at a rate of 20°C / min. The temperature is raised by 100°C, and maintained at each temperature for 21 minutes. (a) The temperature is increased from 40°C to 60°C in 10°C intervals. (b) The temperature is increased from 60°C to 69°C in 3°C intervals. (c) The temperature is increased from 69°C to 100°C in 1°C intervals. (d) The temperature is increased from 100°C to 120°C in 10°C intervals. [2] The polyethylene resin composition according to [1] above, wherein the extracted component obtained by subjecting the polyethylene resin composition to temperature-rise free fractionation in accordance with the "conditions for temperature-rise free fractionation of polyethylene resin composition" in (Condition 1) above has a comonomer content of 0.6 mol % or more and 5 mol % or less when measured by C-NMR. [3] The polyethylene resin composition according to [1] or [2] above, wherein the melting point of an extracted component obtained by subjecting the polyethylene resin composition to temperature-rise free fractionation in accordance with the "conditions for temperature-rise free fractionation of polyethylene resin composition" in (Condition 1) above is 125°C or higher and 135°C or lower. [4] The polyethylene resin composition according to any one of [1] to [3] above, wherein the lamellar thickness of an extracted component obtained by subjecting the polyethylene resin composition to temperature-rise liberation fractionation in accordance with the "conditions for temperature-rise liberation fractionation of polyethylene resin composition" in (Condition 1) above is 6 nm or more and 14 nm or less. [5] The polyethylene resin composition according to any one of [1] to [4] above, wherein the lamellar thickness of an extracted component obtained by subjecting the polyethylene resin composition to temperature-rise liberation fractionation in accordance with the "conditions for temperature-rise liberation fractionation of polyethylene resin composition" in (Condition 1) above is 10 nm or more and 14 nm or less. [6] [6] The polyethylene resin composition according to any one of [1] to [5] above, wherein an extracted component obtained by subjecting the polyethylene resin composition to temperature-rise free fractionation in accordance with the "conditions for temperature-rise free fractionation of polyethylene resin composition" in (Condition 1) above has a weight average molecular weight (Mw) of 20,000 or more and 350,000 or less and a molecular weight distribution (Mw / Mn) of 2 or more and 14 or less. [7] When the CFC of a solution of an extracted component obtained by subjecting the polyethylene resin composition to temperature-increase free fractionation in accordance with the "conditions for temperature-increase free fractionation of polyethylene resin composition" in (Condition 1) above is measured using o-dichlorobenzene as a solvent in accordance with the "conditions for CFC measurement of extracted component" in (Condition 1) above, [7] The polyethylene resin composition according to any one of [1] to [6], wherein the temperature at which the integrated eluted amount reaches 10% by mass of the total eluted amount is 70°C or higher and 90°C or lower. [8] [7] The polyethylene resin composition according to any one of [1] to [7] above, wherein the Ti content of an extractable component obtained by subjecting the polyethylene resin composition to temperature-rise liberation fractionation in accordance with the "conditions for temperature-rise liberation fractionation of polyethylene resin composition" in (Condition 1) above is 5 ppm or less. [9] The polyethylene resin composition according to any one of [1] to [8] above, wherein the Al content of an extractable component obtained by subjecting the polyethylene resin composition to temperature-rise liberation fractionation in accordance with the "conditions for temperature-rise liberation fractionation of a polyethylene resin composition" in (Condition 1) above is 10 ppm or less.

[10] When a solution of the polyethylene resin composition using o-dichlorobenzene as a solvent was measured for CFC under the following conditions (Condition 2), the integrated elution amount at 40°C or higher and lower than 95°C is 15% by mass or higher and 70% by mass or lower of the total elution amount; the integrated elution amount at 95°C or higher and 105°C or lower is 15% by mass or higher of the total elution amount, It has at least two elution peaks, and the temperature at which the maximum elution amount occurs is 88°C or higher and 100°C or lower. The polyethylene resin composition according to any one of [1] to [9] above. (Condition 2) (1) The o-dichlorobenzene solution of the polyethylene resin composition is kept at 140° C. for 120 minutes. (2) The o-dichlorobenzene solution of the polyethylene resin composition is cooled to 40°C at a rate of 0.5°C / min, and then maintained at this temperature for 20 minutes. (3) Using the temperature program shown in (a) to (e) below, the column temperature is increased at a rate of 20°C / min. Each temperature is maintained for 21 minutes. (a) The temperature is increased from 40°C to 60°C in 10°C intervals. (b) The temperature is increased from 60°C to 75°C in 5°C intervals. (c) The temperature is increased from 75°C to 90°C in 3°C intervals. (d) The temperature is increased from 90°C to 110°C in 1°C intervals. (e) The temperature is increased from 110°C to 120°C in 5°C intervals.

[11]

[11] The polyethylene resin composition according to any one of [1] to

[10] above, wherein the polyethylene resin composition has a Ti content of 5 ppm or less.

[12]

[12] The polyethylene resin composition according to any one of [1] to

[11] above, wherein the polyethylene resin composition has an Al content of 10 ppm or less. 〔13〕 A microporous membrane for separators, comprising the polyethylene resin composition according to any one of [1] to

[12] above. 〔14〕 14. The microporous membrane for separators according to claim 13, which has a fuse temperature of less than 135°C. 〔15〕 The microporous membrane for separators according to

[13] or

[14] above, which has a fuse speed of less than 10 seconds. 〔16〕 In a puncture test under the conditions of a needle tip curvature radius of 0.5 mm and a puncture speed of 2 mm / sec, the maximum puncture load is 3.0 N or more. the number of membrane defects present in an area of 250 mm x 250 mm of the microporous membrane for separators made of the polyethylene resin composition is 20 or less; The microporous membrane for separators according to any one of

[13] to

[15] . 〔17〕 The average film thickness is 5 μm or more and 30 μm or less, The variation is less than ±5 μm from the average film thickness. The microporous membrane for separators according to any one of

[13] to

[16] . 〔18〕 A method for producing the microporous membrane for separator according to any one of

[13] to

[17] , A wet method using a solvent includes an extrusion step, a stretching step, an extraction step, and a drying step, The extrusion step is a step of performing extrusion using an extruder equipped with a T-die. A method for manufacturing a microporous membrane for a separator. [Effects of the Invention]

[0012] According to the present invention, a polyethylene resin composition can be obtained which, when processed into a battery separator, has excellent strength and fuse performance, can shorten the time from the start to the completion of fusing, and has few film defects and film thickness unevenness. [Brief explanation of the drawings]

[0013] [Figure 1] 1 shows an image of the measurement results in cross-fractionation chromatography measurement. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. Note that the present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be implemented in various modifications within the scope of its gist.

[0015] In this specification, "fuse performance" refers to the ability of a separator to, for example, cause the temperature to rise in an abnormal event (such as thermal runaway of the battery), melt the polymer, block the micropores, and shut down ion conduction, thereby allowing the battery to be used safely. This fuse performance results in the loss of charge / discharge function, thereby reducing the risk of thermal runaway of the battery.

[0016] [Polyethylene resin composition] The polyethylene resin composition of the present embodiment is The polyethylene resin composition has a weight-average molecular weight (Mw) of 100,000 or more and 1,000,000 or less and a molecular weight distribution (Mw / Mn) of 2.0 or more and 18.0 or less, wherein, when a solution of an extracted component obtained by temperature-rise free fractionation in accordance with the "Conditions for temperature-rise free fractionation of a polyethylene resin composition" in (Condition 1) below is measured using o-dichlorobenzene as a solvent by cross-fractionation chromatography (hereinafter referred to as "CFC") in accordance with the "CFC measurement conditions for the extracted component" in (Condition 1) below, the integrated elution amount at 40°C or more and less than 90°C is 10% by mass or more and less than 70% by mass of the total elution amount, and the integrated elution amount at 90°C or more and 95°C is 10% by mass or more of the total elution amount, and the temperature at which the maximum elution amount occurs is 88°C or more and 100°C or less. (Condition 1) "Temperature-increasing free fractionation conditions for polyethylene resin compositions" (1) Solvent: Toluene (2) Soxhlet extraction time: 6 hours (3) Method for collecting the components extracted into toluene solvent: Add methanol to the toluene solvent. The extract is then filtered off with suction to obtain the extract. "CFC measurement conditions for extracted components" (1) The o-dichlorobenzene solution of the extracted components is kept at 140°C for 120 minutes. (2) The o-dichlorobenzene solution of the extracted components is cooled to 40°C at a rate of 0.5°C / min, and then held for 20 minutes. (3) Using the temperature program shown in (a) to (d) below, the column temperature is increased at a rate of 20°C / min. Each temperature is maintained for 21 minutes. (a) The temperature is increased from 40°C to 60°C in 10°C intervals. (b) The temperature is increased from 60°C to 69°C in 3°C intervals. (c) The temperature is increased from 69°C to 100°C in 1°C intervals. (d) The temperature is increased from 100°C to 120°C in 10°C intervals. The above requirements will be explained below.

[0017] The polyethylene resin composition of the present embodiment contains an ethylene-based polymer (hereinafter also referred to as "polyethylene"). Examples of ethylene-based polymers include ethylene homopolymers and copolymers (e.g., copolymers or terpolymers) of ethylene and other comonomers copolymerizable with ethylene. The bonding form of the copolymer may be random or block. The other comonomers are not particularly limited, but examples thereof include α-olefins and vinyl compounds. The other comonomers may be used singly or in combination of two or more. The α-olefin is not particularly limited, but examples thereof include α-olefins having 3 to 20 carbon atoms, specifically propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, etc. Among these, the other comonomer is preferably propylene and / or 1-butene, from the viewpoint of further improving the heat resistance and strength of molded articles such as membranes and fibers. The vinyl compound is not particularly limited, but examples thereof include vinylcyclohexane, styrene, and derivatives thereof. Furthermore, as other comonomers, non-conjugated polyenes such as 1,5-hexadiene and 1,7-octadiene may be used as needed.

[0018] The polyethylene resin composition of the present embodiment can be used in the form of a mixture obtained by mixing (blending) ethylene polymers having different weight-average molecular weights, molecular weight distributions, etc., or in the form of a mixture obtained by mixing (blending) with various resins such as low-density polyethylene, linear low-density polyethylene, polypropylene, and polystyrene. It may also be a product obtained by multistage polymerization. It may also be a molded article obtained by molding the above-mentioned mixture. It may also be a mixture of an ethylene polymer and an additive such as an antioxidant.

[0019] (Weight average molecular weight (Mw) of polyethylene resin composition) The weight average molecular weight (Mw) of the polyethylene resin composition of the present embodiment is 100,000 or more and 1,000,000 or less, preferably 120,000 or more and 800,000 or less, and more preferably 140,000 or more and 600,000 or less. The Mw of the polyethylene resin composition can be controlled within the above-mentioned range by using a catalyst described below and appropriately adjusting the polymerization conditions, etc. Specifically, the weight-average molecular weight (Mw) can be controlled by, for example, making hydrogen present in the polymerization system or changing the polymerization temperature. Furthermore, the molecular weight can be controlled within an appropriate range by adding hydrogen as a chain transfer agent to the polymerization system.

[0020] A weight-average molecular weight (Mw) of 100,000 or more can improve strength, while a weight-average molecular weight (Mw) of 1,000,000 or less can facilitate melt flowability, dissolution in a solvent, stretching, and the like, thereby improving processability and reducing film defects and film thickness unevenness.

[0021] (Molecular weight distribution (Mw / Mn) of polyethylene resin composition) The molecular weight distribution (Mw / Mn) of the polyethylene resin composition of the present embodiment is 2.0 or more and 18.0 or less, preferably 4.0 or more and 18.0 or less, and more preferably 6.0 or more and 17.0 or less. In the polyethylene resin composition of the present embodiment, the molecular weight distribution of the polyethylene resin composition can be narrowed by using a catalyst, maintaining constant conditions in the polymerization system (hydrogen concentration, temperature, ethylene pressure, etc.), and the like. Therefore, continuous polymerization is preferred. On the other hand, examples of methods for widening the molecular weight distribution of the polyethylene resin composition include a method of changing the conditions during polymerization in batch polymerization (e.g., a method of changing the concentration of hydrogen, which is a chain transfer agent, during polymerization), and a method of intermittently introducing a catalyst in batch polymerization.

[0022] When the molecular weight distribution (Mw / Mn) is 2.0 or more, the polyethylene resin composition of this embodiment has better moldability, and as a result, the stretched molded article, microporous membrane, and battery separator have excellent strength. On the other hand, when the molecular weight distribution (Mw / Mn) is 18.0 or less, the molecular chain length becomes uniform, and better strength can be achieved.

[0023] The number average molecular weight (Mn), weight average molecular weight (Mw), and molecular weight distribution (Mw / Mn) of the polyethylene resin composition of this embodiment can be determined by measuring an o-dichlorobenzene solution in which an ethylene polymer is dissolved by gel permeation chromatography (hereinafter also referred to as "GPC") and based on a calibration curve prepared using commercially available monodisperse polystyrene. More specifically, they can be measured by the method described in the Examples below.

[0024] (Extractable components obtained by temperature-elevated liberation fractionation of polyethylene resin composition) The polyethylene resin composition of the present embodiment is subjected to temperature-increase free fractionation in accordance with the above-mentioned (Condition 1) "Conditions for temperature-increase free fractionation of polyethylene resin composition", and the extracted component obtained is measured by CFC in accordance with the above-mentioned (Condition 1) "CFC measurement conditions for extracted component", and the integrated elution amount at 40°C or higher and lower than 90°C is 10% by mass or higher and lower than 70% by mass, preferably 15% by mass or higher and 65% by mass or lower, more preferably 20% by mass or higher and 60% by mass or lower, and even more preferably 30% by mass or higher and 60% by mass or lower of the total elution amount. The integrated elution amount at temperatures from 90° C. to 95° C. is 10% by mass or more of the total elution amount, preferably 13% by mass or more, and more preferably 15% by mass or more. The temperature at which the maximum elution amount occurs is 88°C or higher and 100°C or lower, preferably 90°C or higher and 97°C or lower, and more preferably 92°C or higher and 95°C or lower. Figure 1 shows an image of the relationship between temperature and elution amount in CFC measurement. The extracted component obtained by subjecting the polyethylene resin composition of this embodiment to temperature-rise liberation fractionation according to the "conditions for temperature-rise liberation fractionation of polyethylene resin composition" (condition 1) above is the most effective component (the component that causes fusing) for improving the fuse performance of the microporous membrane of this embodiment. The integrated elution amount of this extracted component at temperatures between 40°C and 90°C is between 10% and 70% by mass of the total elution amount, the integrated elution amount at temperatures between 90°C and 95°C is at least 10% by mass of the total elution amount, and the temperature at which the maximum elution amount occurs is between 88°C and 95°C. This allows component (A), which elutes at low temperatures of between 40°C and 90°C, to begin flowing in the microporous membrane. Component (B), which elutes at temperatures between 90°C and 95°C, can moderately reduce the rigidity of the components that form the pores in the microporous membrane, thereby shortening the time until the pores are closed. In other words, improved fuse performance and a shorter time from the start to completion of fusing (hereinafter also referred to as the "fuse rate") can be simultaneously achieved. Furthermore, the extractable component preferably exhibits an elution behavior in which the amount of elution gradually increases with increasing temperature in the temperature range of not less than 40° C. and less than 90° C. Gradual elution means that the time required for a component in the polyethylene resin composition corresponding to the extractable component to swell can be made slower in the step of swelling and dissolving the polyethylene resin composition with liquid paraffin, and this tends to reduce the possibility of unmelted components agglomerating to form defects due to insufficient swelling of the polyethylene resin composition.

[0025] In order to control the integrated elution amount at 40°C or higher and lower than 90°C to 10% by mass or more and lower than 70% by mass of the total elution amount, the integrated elution amount at 90°C or higher and lower than 95°C to 30% by mass or more of the total elution amount, and the temperature at which the maximum elution amount occurs to 88°C or higher and 95°C or lower, when the extractable components obtained by temperature-rise liberation fractionation of the polyethylene resin composition of the present embodiment are measured by CFC, it is important to control the production method of the ethylene polymer contained in the polyethylene resin composition. That is, examples of methods for producing the ethylene polymer constituting the polyethylene resin composition of this embodiment include a method of initiating polymerization on the active sites of the catalyst in an environment with a low catalyst concentration. For example, a method of preventing the polymerization reaction and catalyst activation from occurring for a short time immediately after catalyst feeding is included. Specific examples include adjusting the temperature of the catalyst to be introduced into the reactor to less than 5°C, providing a catalyst feed port, an ethylene feed port, and a hexane feed port containing dissolved ethylene at the bottom of the reactor, and simultaneously introducing all of them into the reactor. Also included are methods of introducing hexane containing dissolved ethylene into the reactor through the hexane feed port at a temperature less than 5°C, and then introducing the remaining ethylene through the ethylene feed port. Other examples include a method of diffusing the catalyst before it first comes into contact with ethylene. More specific examples include introducing the catalyst and hexane containing dissolved ethylene into the reactor from multiple locations, and controlling the linear catalyst feed velocity to 3.0 m / s or more and 5.0 m / s or less.

[0026] Here, "cross-fractionation chromatography (CFC)" refers to an apparatus that combines a temperature-rising elution fractionation section (hereinafter also referred to as "TREF section") for crystallinity fractionation with a GPC section for molecular weight fractionation. By directly connecting the TREF section and the GPC section, it is possible to analyze the correlation between composition distribution and molecular weight distribution. Note that measurements in the TREF section may also be referred to as measurements in CFC.

[0027] Measurement by the TREF unit is carried out as follows based on the principle described in "Journal of Applied Polymer Science, Vol. 26, 4217-4231 (1981)". The ethylene polymer to be measured is completely dissolved in o-dichlorobenzene. The solution is then cooled at a constant temperature to form a thin polymer layer on the surface of the inert carrier. During this process, highly crystalline components crystallize first, followed by less crystalline components as the temperature decreases. The temperature is then increased in stages, and the components with lower crystallinity are eluted in order, from the least crystalline to the most crystalline. The concentrations of the eluted components at a given temperature can be detected.

[0028] The elution amount at each temperature and the elution integrated amount of the extractable component obtained by temperature-elevated release fractionation from the polyethylene resin composition can be determined by measuring the elution temperature-elution amount curve using the TREF section as follows. Specifically, first, a column containing a packing material is heated to 140°C, and a sample solution (e.g., concentration: 20 mg / 20 mL) prepared by dissolving extracted components obtained by temperature-elevated liberation fractionation from a polyethylene resin composition in o-dichlorobenzene is introduced and maintained for 120 minutes.

[0029] Next, the temperature is lowered to 40°C at a rate of 0.5°C / min and then maintained for 20 minutes to precipitate the sample on the packing surface. The column temperature is then gradually increased at a rate of 20°C / min. The temperature is increased from 40°C to 60°C at 10°C intervals, from 60°C to 69°C at 3°C intervals, from 69°C to 100°C at 1°C intervals, and from 100°C to 120°C at 10°C intervals. After maintaining each temperature for 21 minutes, the temperature is increased again, and the concentration of the sample eluted at each temperature is detected. An elution temperature-elution amount curve is then measured using the elution amount (mass%) of the sample and the temperature (°C) inside the column at that time, and the elution amount and elution integral at each temperature are obtained. More specifically, this can be measured by the method described in the Examples below.

[0030] (Temperature rise liberation fractionation) Here, temperature-rise liberation fractionation is a method in which a solvent is used to dissolve and extract a target component that is soluble in a solvent from a sample using a general Soxhlet extractor. A Soxhlet extractor is an apparatus consisting of a heater and a container containing a solvent at the bottom, a tube in the middle for holding filter paper containing the sample, and a cooling tube at the top. When the container containing the solvent is heated, the solvent evaporates, is cooled by the cooling tube at the top, drips into the sample, dissolves a small amount of solvent-soluble matter, and then returns to the container containing the solvent. Because the solvent-soluble matter has a higher boiling point than the solvent, by repeating this cycle, the solvent-soluble matter (extracted components) gradually concentrates in the container containing the solvent, leaving solvent-insoluble matter (residue) in the filter paper. While toluene, xylene, etc. are commonly used as solvents, in this embodiment, toluene is used as described above (Condition 1).

[0031] (Comonomer content of extracted components) The comonomer content of the extracted component obtained by subjecting the polyethylene resin composition of the present embodiment to temperature-increase free fractionation in accordance with the "conditions for temperature-increase free fractionation of polyethylene resin composition" in (Condition 1) above is preferably 0.01 mol % or more and 5 mol % or less, more preferably 0.05 mol % or more and 3 mol % or less, and even more preferably 0.1 mol % or more and 2 mol % or less. A comonomer content of 0.01 mol% or more provides superior fuse performance, while a comonomer content of 5 mol% or less provides a faster fuse rate. As a result, when the polyethylene resin composition of this embodiment is processed into a microporous membrane, in the event of an abnormality (such as thermal runaway in a battery), the temperature rises, causing the polymer to melt, blocking the micropores and shutting down ion conduction, resulting in the loss of charge / discharge function and reducing the risk of thermal runaway in the battery. The comonomer content of the extracted component can be measured by 13C-NMR, specifically, by the method described in the examples below. <Means of achievement> Examples of methods for controlling the comonomer content of the extracted components obtained by temperature-elevated free fractionation from the polyethylene resin composition of this embodiment to 0.01 mol % or more and 5 mol % or less include initiating polymerization on the active sites of the catalyst in an environment with a low catalyst concentration. For example, methods include preventing the polymerization reaction and catalyst activation from occurring for a short time immediately after catalyst feeding. Specific examples include adjusting the temperature of the catalyst introduced into the reactor to less than 5°C, providing the catalyst feed port, ethylene feed port, and hexane feed port containing dissolved ethylene at the bottom of the reactor, and simultaneously introducing all of them into the reactor. Also included are methods for introducing hexane containing dissolved ethylene into the reactor through the hexane feed port at a temperature below 5°C, and introducing the remaining ethylene through the ethylene feed port. Other examples include diffusing the catalyst before it first comes into contact with ethylene. Specific examples include introducing the catalyst and hexane containing dissolved ethylene into the reactor from multiple locations, and controlling the linear catalyst feed velocity to 3.0 m / s or more and 5.0 m / s or less. Another method is to adjust the amount of comonomer added.

[0032] (Melting point of extracted component) The melting point of the extracted component obtained by subjecting the polyethylene resin composition of the present embodiment to temperature-rise free fractionation in accordance with the "conditions for temperature-rise free fractionation of polyethylene resin composition" in (Condition 1) above is preferably 125°C or higher and 135°C or lower, more preferably 125°C or higher and 132°C or lower, and even more preferably 125°C or higher and 130°C or lower. When the melting point of the extracted component is 125°C or higher, the fuse performance is superior and heat setting can be performed without blocking the pores of the microporous membrane of the polyethylene resin composition of this embodiment. When the melting point is 135°C or lower, the fuse rate can be increased. As a result, when the polyethylene resin composition of this embodiment is processed into a microporous membrane, in the event of an abnormality (such as thermal runaway in a battery), the temperature rises, causing the polymer to melt, blocking the pores and shutting down ionic conduction, resulting in loss of charge / discharge function and reducing the risk of thermal runaway in the battery. The melting point of the extracted component can be measured by the method described in the Examples below. <Means of achievement> Examples of methods for controlling the melting point of the extracted component obtained by temperature-elevated free fractionation from the polyethylene resin composition of this embodiment to 125°C or higher and 135°C or lower include initiating polymerization on the active sites of the catalyst in an environment with a low catalyst concentration. For example, methods include preventing the polymerization reaction and catalyst activation from occurring for a short period of time immediately after catalyst feeding. Specific examples include adjusting the temperature of the catalyst introduced into the reactor to less than 5°C, providing a catalyst feed port, an ethylene feed port, and a hexane feed port containing dissolved ethylene at the bottom of the reactor, and simultaneously introducing all of them into the reactor. Also included are methods for introducing hexane containing dissolved ethylene into the reactor through the hexane feed port at a temperature below 5°C, and introducing the remaining ethylene through the ethylene feed port. Other methods include diffusing the catalyst before it first comes into contact with ethylene. Specific examples include introducing the catalyst and hexane containing dissolved ethylene into the reactor from multiple locations, and controlling the linear catalyst feed velocity to 3.0 m / s or higher and 5.0 m / s or lower.

[0033] (Lamellar thickness of extracted components) The lamellar thickness of the extracted component obtained by subjecting the polyethylene resin composition of the present embodiment to temperature-rise liberation fractionation in accordance with the above-mentioned (Condition 1) "Conditions for temperature-rise liberation fractionation of polyethylene resin composition" is preferably 6 nm or more and 14 nm or less, more preferably 8 nm or more and 14 nm or less, and even more preferably 10 nm or more and 14 nm or less. A lamellar thickness of 6 nm or more results in superior fuse performance, while a lamellar thickness of 14 nm or less results in a faster fuse speed. As a result, when the polyethylene resin composition of this embodiment is processed into a microporous membrane, in the event of an abnormality (such as thermal runaway in a battery), the temperature rises, causing the polymer to melt, blocking the micropores and shutting down ion conduction, resulting in the loss of charge / discharge function and reducing the risk of thermal runaway in the battery. The lamellar thickness of the extracted component can be measured by the method described in the Examples below. <Means of achievement> Examples of methods for controlling the lamellar thickness of the extracted component obtained by temperature-elevated free fractionation of the polyethylene resin composition of this embodiment to 6 to 14 nm, preferably 10 to 14 nm, include initiating polymerization on the active sites of the catalyst in an environment with a low catalyst concentration. For example, methods include preventing the polymerization reaction and catalyst activation from occurring for a short time immediately after catalyst feeding. Specific examples include adjusting the temperature of the catalyst to be introduced into the reactor to less than 5°C, providing a catalyst feed port, an ethylene feed port, and a hexane feed port containing dissolved ethylene at the bottom of the reactor, and simultaneously introducing all of them into the reactor. Also included are methods for introducing hexane containing dissolved ethylene into the reactor through the hexane feed port at a temperature less than 5°C, and introducing the remaining ethylene through the ethylene feed port. Other methods include diffusing the catalyst before it first comes into contact with ethylene. Specific examples include introducing the catalyst and hexane containing dissolved ethylene into the reactor from multiple locations, and controlling the linear catalyst feed velocity to 3.0 to 5.0 m / s.

[0034] (Weight average molecular weight (Mw) of extracted component) The weight average molecular weight (Mw) of the extracted component obtained by subjecting the polyethylene resin composition of the present embodiment to temperature-increasing free fractionation in accordance with the "conditions for temperature-increasing free fractionation of polyethylene resin composition" in (Condition 1) above is preferably 20,000 or more and 350,000 or less, more preferably 50,000 or more and 300,000 or less, and even more preferably 70,000 or more and 250,000 or less. The Mw of the extracted component can be controlled within the above-mentioned range by using a catalyst described below and appropriately adjusting the polymerization conditions, etc. Specifically, the weight-average molecular weight (Mw) of the extracted component can be controlled by, for example, making hydrogen present in the polymerization system of the ethylene polymer or changing the polymerization temperature. The weight-average molecular weight can be controlled within an appropriate range by adding hydrogen as a chain transfer agent to the polymerization system.

[0035] When the weight-average molecular weight (Mw) of the extracted component is 20,000 or more, the strength can be further improved, while when the weight-average molecular weight (Mw) of the extracted component is 350,000 or less, the melt flowability, dissolution in a solvent, stretching, etc. are facilitated, improving processability.

[0036] (Molecular weight distribution of extracted components (Mw / Mn) The molecular weight distribution (Mw / Mn) of the extracted component obtained by subjecting the polyethylene resin composition of this embodiment to temperature-rise free fractionation in accordance with the "temperature-rise free fractionation conditions for polyethylene resin composition" in (Condition 1) above is preferably 2.0 or more and 14.0 or less, more preferably 4.0 or more and 13.0 or less, and even more preferably 6.0 or more and 12.0 or less. The molecular weight distribution of the extracted component can be narrowed by using a catalyst described below in the polymerization step of the ethylene polymer or by maintaining constant conditions in the polymerization system (hydrogen concentration, temperature, ethylene pressure, etc.). For this reason, continuous polymerization is preferred. On the other hand, methods for widening the molecular weight distribution of the extracted component include a method of changing the polymerization conditions during batch polymerization (for example, a method of changing the concentration of hydrogen as a chain transfer agent during polymerization) and a method of intermittently introducing a catalyst during batch polymerization.

[0037] When the molecular weight distribution (Mw / Mn) of the extracted component is 2.0 or more, the polyethylene resin composition of the present embodiment has better moldability, and as a result, the stretched molded article, microporous membrane, and battery separator have excellent dimensional accuracy and strength. On the other hand, when the molecular weight distribution (Mw / Mn) of the extracted component is 14.0 or less, the molecular chain length becomes uniform, resulting in better strength.

[0038] (The temperature at which the integrated elution amount of the extracted components reaches 10% by mass of the total elution amount when measuring CFC) The temperature at which the integrated eluted amount of an extracted component obtained by subjecting the polyethylene resin composition of the present embodiment to temperature-increase free fractionation in accordance with the "Conditions for temperature-increase free fractionation of polyethylene resin composition" in (Condition 1) above reaches 10% by mass of the total eluted amount when measured by CFC in accordance with the "CFC measurement conditions for extracted component" in (Condition 1) above is preferably 70°C or higher and 90°C or lower, more preferably 72°C or higher and 90°C or lower, and even more preferably 75°C or higher and 90°C. The temperature at which the integrated elution amount reaches 10% by mass of the total elution amount when measured with CFC is in the low temperature range of 70°C to 90°C, which enables excellent fuse performance and a faster fuse speed. As a result, when processed into a microporous membrane, in the event of an abnormality (such as thermal runaway in a battery), the temperature rises, causing the polymer to melt, blocking the micropores and shutting down ion conduction, resulting in the loss of charge and discharge function and reducing the risk of thermal runaway in the battery. <Means of achievement> Examples of a method for controlling the temperature at which the integrated elution amount of the extracted components obtained by temperature-elevated free fractionation of the polyethylene resin composition of this embodiment reaches 10% by mass of the total elution amount, as measured by CFC, to 70°C or higher and 90°C or lower include a method of initiating polymerization on the active sites of the catalyst in an environment with a low catalyst concentration. For example, a method of preventing the polymerization reaction and catalyst activation from occurring for a short time immediately after catalyst feeding is included. Specific examples include adjusting the temperature of the catalyst introduced into the reactor to less than 5°C, providing a catalyst feed port, an ethylene feed port, and a hexane feed port containing dissolved ethylene at the bottom of the reactor, and introducing all of them into the reactor simultaneously, or introducing hexane containing dissolved ethylene into the reactor through the hexane feed port at less than 5°C, and introducing the remaining ethylene through the ethylene feed port. Other examples include a method of diffusing the catalyst before it first comes into contact with ethylene. Specific examples include introducing the catalyst and ethylene-dissolved hexane into the reactor from multiple locations, and controlling the catalyst feed linear velocity to 3.0 m / s or higher and 5.0 m / s or lower.

[0039] (Ti and Al content of extracted components) The titanium (Ti) content of the extracted component obtained by subjecting the polyethylene resin composition of this embodiment to temperature-rise liberation fractionation in accordance with the "conditions for temperature-rise liberation fractionation of polyethylene resin composition" in (Condition 1) above is preferably 5 ppm or less, more preferably 4 ppm or less, and even more preferably 3 ppm or less. The aluminum (Al) content is preferably 10 ppm or less, more preferably 8 ppm or less, and even more preferably 6 ppm or less. By controlling the amount of metal in this way, it is possible to suppress the reaction with antioxidants and heat stabilizers, and it is possible to suppress the coloring of the molded product due to the formation of organometallic complexes. Furthermore, by controlling the amount of metal in the extracted components, it is possible to obtain fibers with a uniform diameter and films with a uniform thickness. The contents of Ti and Al in the extracted components can be controlled by the productivity of the ethylene polymer per unit catalyst. The productivity of the ethylene polymer can be controlled by the polymerization temperature, polymerization pressure, and slurry concentration of the reactor during production. As other methods, the metal amounts can be controlled by selecting the type of co-catalyst component during polymerization of the ethylene polymer, lowering the concentration of the co-catalyst component, or washing the ethylene polymer with an acid or alkali. In this embodiment, the amounts of Ti and Al can be measured by the method described in the Examples below.

[0040] (Cross fractionation chromatography (CFC) measurement of polyethylene resin composition) In a solution of the polyethylene resin composition of the present embodiment using o-dichlorobenzene as a solvent, the integrated elution amount at 40°C or higher and lower than 95°C, as measured by CFC in accordance with the following <Condition 2>, is preferably from 15 to 70% by mass of the total elution amount, more preferably from 25 to 70% by mass, and even more preferably from 35 to 65% by mass. The integrated elution amount at temperatures from 95° C. to 105° C. is preferably 15% by mass or more of the total elution amount, more preferably 20% by mass or more, and even more preferably 25% by mass or more. Furthermore, it is preferable that there are at least two or more peaks, and the temperature at which the maximum elution amount occurs is preferably 88°C or higher and 100°C or lower, and more preferably 88°C or higher and 95°C or lower. <Condition 2> (1) The o-dichlorobenzene solution of the polyethylene resin composition is kept at 140° C. for 120 minutes. (2) The o-dichlorobenzene solution of the polyethylene resin composition is cooled to 40°C at a rate of 0.5°C / min, and then maintained at this temperature for 20 minutes. (3) Using the temperature program shown in (a) to (e) below, the column temperature is increased at a rate of 20°C / min. Each temperature is maintained for 21 minutes. (a) The temperature is increased from 40°C to 60°C in 10°C intervals. (b) The temperature is increased from 60°C to 75°C in 5°C intervals. (c) The temperature is increased from 75°C to 90°C in 3°C intervals. (d) The temperature is increased from 90°C to 110°C in 1°C intervals. (e) The temperature is increased from 110°C to 120°C in 5°C intervals.

[0041] When measured using a CFC, the integrated elution amount at temperatures from 40°C to less than 95°C is 15% by mass to 70% by mass of the total elution amount, the integrated elution amount at temperatures from 95°C to 105°C is 15% by mass or more of the total elution amount, there are at least two peaks, and the temperature at which the maximum elution amount occurs is 88°C to 100°C, thereby enabling further improvement in fuse performance and fuse speed, and enabling the membrane shape to be maintained even after the micropores are blocked, thereby preventing short circuits between electrodes, further improving battery safety, and tending to further improve the strength of the membrane itself.

[0042] When a solution of the polyethylene resin composition of this embodiment using o-dichlorobenzene as a solvent is subjected to CFC measurement in accordance with the above (Condition 2), the integrated elution amount at 40°C or higher and lower than 95°C is 15% by mass or higher and 70% by mass or lower of the total elution amount, the integrated elution amount at 95°C or higher and lower than 105°C is 15% by mass or higher of the total elution amount, and the temperature at which the maximum elution amount occurs is 88°C or higher and 100°C or lower. Examples of a method for controlling the temperature at which the maximum elution amount occurs include, in producing an ethylene polymer contained in the polyethylene resin composition of this embodiment, adjusting the temperature of a catalyst charged into a reactor to less than 5°C, and Effective methods include providing the catalyst feed port, ethylene feed port, and hexane feed port with ethylene dissolved therein all at the bottom of the reactor and introducing them all into the reactor simultaneously; introducing hexane with ethylene dissolved therein through the hexane feed port at a temperature of less than 5°C into the reactor and introducing the remaining ethylene through the ethylene feed port; providing the catalyst feed port, ethylene feed port, and hexane feed port with ethylene dissolved therein all at the bottom of the reactor and introducing them all into the reactor simultaneously; and intermittently introducing the solid catalyst and co-catalyst alternately into the reactor so that they come into contact with each other the moment they are introduced into the reactor.

[0043] The elution amount and elution integrated amount of the polyethylene resin composition at each temperature can be determined by measuring the elution temperature-elution amount curve using the TREF unit as follows: Specifically, first, a column containing a packing material is heated to 140°C, and a sample solution (e.g., concentration: 20 mg / 20 mL) prepared by dissolving the polyethylene resin composition in o-dichlorobenzene is introduced and maintained for 120 minutes.

[0044] Next, the temperature is decreased to 40°C at a rate of 0.5°C / min and then maintained for 20 minutes to precipitate the sample on the packing surface. The column temperature is then increased sequentially at a rate of 20°C / min. The temperature is increased from 40°C to 60°C at 10°C intervals, from 60°C to 75°C at 5°C intervals, from 75°C to 90°C at 3°C intervals, from 90°C to 110°C at 1°C intervals, and from 110°C to 120°C at 5°C intervals. After maintaining each temperature for 21 minutes, the temperature is increased again, and the concentration of the sample eluted at each temperature is detected. An elution temperature-elution amount curve is then measured based on the elution amount (mass%) of the sample and the temperature (°C) in the column at that time, and the elution amount and elution integral at each temperature are obtained. More specifically, this can be measured by the method described in the Examples below.

[0045] (Ti and Al contents of polyethylene resin composition) The polyethylene resin composition of the present embodiment has a titanium (Ti) content of preferably 5 ppm or less, more preferably 4 ppm or less, and even more preferably 3 ppm or less, and an aluminum (Al) content of preferably 10 ppm or less, more preferably 8 ppm or less, and even more preferably 6 ppm or less. By adjusting the amount of metal in this manner, it is possible to suppress the reaction with antioxidants and heat stabilizers, and it is possible to suppress the coloring of the molded product due to the formation of organometallic complexes. Furthermore, by adjusting the amount of metal in the polyethylene resin composition, it is possible to obtain fibers with a uniform diameter when made into fibers, and a film with a uniform thickness when made into a film. The contents of Ti and Al in the polyethylene resin composition can be controlled by the productivity of the ethylene polymer per unit catalyst. The productivity of the ethylene polymer can be controlled by the polymerization temperature, polymerization pressure, and slurry concentration of the reactor during production. As other methods, the metal amounts can be controlled by selecting the type of co-catalyst component during polymerization of the ethylene polymer, lowering the concentration of the co-catalyst component, or washing the ethylene polymer with an acid or alkali. In the present embodiment, the amounts of Ti and Al can be measured by the method described in the Examples below.

[0046] [Method for producing ethylene polymer contained in polyethylene resin composition of the present embodiment] (catalyst component) The polyethylene resin composition of the present embodiment contains a polyethylene polymer. The polyethylene polymer can be produced by carrying out a polymerization step in the presence of a predetermined catalyst. The catalyst component is not particularly limited, but examples thereof include general Ziegler-Natta catalysts and metallocene catalysts.

[0047] <Ziegler-Natta catalyst> The Ziegler-Natta catalyst is preferably a catalyst comprising a solid catalyst component [A] and an organometallic compound component [B], wherein the solid catalyst component [A] is an olefin polymerization catalyst produced by reacting an organomagnesium compound (A-1) represented by the following formula (1) which is soluble in an inert hydrocarbon solvent with a titanium compound (A-2) represented by the following formula (2). (A-1):(M 1 )α(Mg)β(R 2 ) a (R 3 ) b (Y 1 ) c ...(Formula 1) (In formula 1, M 1 is a metal atom belonging to the group consisting of groups 12, 13, and 14 of the periodic table, and R 2 and R 3 is a hydrocarbon group having 2 to 20 carbon atoms, and Y 1 is alkoxy, siloxy, aryloxy, amino, amido, -N=CR 4 , R 5 , -SR 6 (where R 4 , R 5 and R 6 represents a hydrocarbon group having 1 to 20 carbon atoms. When c is 2, Y 1may be different from each other.) or a β-keto acid residue, and α, β, a, b, and c are real numbers that satisfy the following relationships: 0≦α, 0<β, 0≦a, 0≦b, 0≦c, 0 <a+b、0≦c / (α+β)≦2、nα+2β=a+b+c(ここで、nはM 1 Represents the valence of .))

[0048] (A-2): Ti(OR 7 ) d X 1 (4-d) ...(Formula 2) (In Equation 2, d is a real number between 0 and 4, and R 7 is a hydrocarbon group having 1 to 20 carbon atoms, and X 1 is a halogen atom.)

[0049] The inert hydrocarbon solvent used in the reaction of the organomagnesium compound (A-1) with the titanium compound (A-2) is not particularly limited, but examples thereof include aliphatic hydrocarbons such as pentane, hexane, and heptane; aromatic hydrocarbons such as benzene and toluene; and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane.

[0050] First, the organomagnesium compound (A-1) will be explained. The (A-1) is shown in the form of an organomagnesium complex compound soluble in an inert hydrocarbon solvent, and includes all dihydrocarbylmagnesium compounds and complexes of these compounds with other metal compounds. The relationship nα+2β=a+b+c between the symbols α, β, a, b, and c indicates the stoichiometry of the valence of the metal atom and the substituent.

[0051] In the formula 1, R 2 and R 3 The hydrocarbon group having 2 to 20 carbon atoms is not particularly limited, but may be, for example, an alkyl group, a cycloalkyl group, or an aryl group, and specific examples thereof include ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, cyclohexyl, and phenyl groups. Among these, alkyl groups are preferred. When α>0, the metal atom M1 As the metal atom, a metal atom belonging to the group consisting of Groups 12, 13 and 14 of the periodic table can be used, such as zinc, boron, aluminum, etc. Among these, aluminum and zinc are preferred.

[0052] metal atom M 1 The ratio of magnesium to R: β / α is not particularly limited, but is preferably 0.1 or more and 30 or less, and more preferably 0.5 or more and 10 or less. When a predetermined organomagnesium compound with α=0 is used, for example, R 2 When R is 1-methylpropyl or the like, it is soluble in an inert hydrocarbon solvent, and such a compound also gives preferable results in this embodiment. 2 , R 3 It is preferable that the above-mentioned formula (1) satisfies any one of the following three groups (1), (2), and (3).

[0053] Group(1):R 2 , R 3 At least one of R is a secondary or tertiary alkyl group having 4 to 6 carbon atoms, preferably R 2 , R 3 are both alkyl groups having 4 to 6 carbon atoms, and at least one of them is a secondary or tertiary alkyl group. Group(2):R 2 and R 3 and R are alkyl groups having different numbers of carbon atoms, preferably 2 is an alkyl group having 2 or 3 carbon atoms, and R 3 is an alkyl group having 4 or more carbon atoms. Group(3):R 2 , R 3 At least one of R is a hydrocarbon group having 6 or more carbon atoms, and preferably R 2 , R 3 The total number of carbon atoms contained in the alkyl group is 12 or more.

[0054] These groups are specifically shown below. In group (1), examples of the secondary or tertiary alkyl group having 4 to 6 carbon atoms include 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, etc. In particular, the 1-methylpropyl group is preferred.

[0055] In addition, in group (2), examples of the alkyl group having 2 or 3 carbon atoms include ethyl, 1-methylethyl, and propyl groups. In particular, the ethyl group is preferred. In addition, examples of the alkyl group having 4 or more carbon atoms include, but are not limited to, butyl, pentyl, hexyl, heptyl, and octyl groups. In particular, butyl and hexyl groups are preferred.

[0056] Furthermore, in group (3), the hydrocarbon group having 6 or more carbon atoms is not particularly limited, but examples thereof include hexyl, heptyl, octyl, nonyl, decyl, phenyl, 2-naphthyl groups, etc. Among the hydrocarbon groups, alkyl groups are preferred, and among the alkyl groups, hexyl and octyl groups are particularly preferred.

[0057] Generally, as the number of carbon atoms contained in the alkyl group increases, the compound tends to be more soluble in an inert hydrocarbon solvent and the viscosity of the solution tends to increase. Therefore, it is preferable to use an alkyl group with a moderate chain length for ease of handling. The organomagnesium compound can be used after being diluted with an inert hydrocarbon solvent, but it can also be used without any problems even if a trace amount of Lewis basic compound such as an ether, ester, or amine is contained or remains in the solution.

[0058] Next, Y 1 In the above (Equation 1), Y 1 is alkoxy, siloxy, aryloxy, amino, amido, -N=CR 4 ,R 5 , -SR 6 (where R 4 , R 5 and R6 Each independently represents a hydrocarbon group having 2 to 20 carbon atoms, or a β-keto acid residue.

[0059] In the formula 1, R 4 , R 5 and R 6 The hydrocarbon group represented by the formula (I) is preferably an alkyl group or aryl group having 1 to 12 carbon atoms, more preferably an alkyl group or aryl group having 3 to 10 carbon atoms. Examples of the hydrocarbon group include, but are not limited to, 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. Particularly preferred are butyl, 1-methylpropyl, 2-methylpentyl, and 2-ethylhexyl groups.

[0060] In addition, in the formula (1), Y 1 is preferably an alkoxy group or a siloxy group. Examples of the alkoxy group include, but are not limited to, methoxy, ethoxy, propoxy, 1-methylethoxy, butoxy, 1-methylpropoxy, 1,1-dimethylethoxy, pentoxy, hexoxy, 2-methylpentoxy, 2-ethylbutoxy, 2-ethylpentoxy, 2-ethylhexoxy, 2-ethyl-4-methylpentoxy, 2-propylheptoxy, 2-ethyl-5-methyloctoxy, octoxy, phenoxy, and naphthoxy groups. In particular, butoxy, 1-methylpropoxy, 2-methylpentoxy, and 2-ethylhexoxy groups are preferred. Examples of the siloxy group include, but are not limited to, hydrodimethylsiloxy, ethylhydromethylsiloxy, diethylhydrosiloxy, trimethylsiloxy, ethyldimethylsiloxy, diethylmethylsiloxy, and triethylsiloxy groups. Particularly preferred are hydrodimethylsiloxy, ethylhydromethylsiloxy, diethylhydrosiloxy, and trimethylsiloxy groups.

[0061] The method for synthesizing the organomagnesium compound (A-1) is not particularly limited. For example, a compound represented by the formula R 2 MgX 1 , and formula R 2 Mg(R 2 has the meaning mentioned above, and X 1 is a halogen.) and an organomagnesium compound of the formula M 1 R 3 n and M 1 R 3 (n-1) H(M 1 , and R 3 has the meaning as above, and n is M 1 ) in an inert hydrocarbon solvent at a temperature of 25°C to 150°C, and if necessary, subsequently reacting with an organometallic compound of formula Y 1 -H(Y 1 has the same meaning as above.) or Y 1 Among these, the compound can be synthesized by reacting an organomagnesium compound and / or an organoaluminum compound having a functional group represented by the formula Y 1 When reacting a compound represented by formula Y with a compound represented by formula Y, the order of the reactions is not particularly limited. 1 -H, a method of adding a compound represented by formula Y 1 Either a method of adding the organomagnesium compound to the compound represented by -H or a method of adding both simultaneously can be used.

[0062] In this embodiment, the ratio of Y to all metal atoms in the organomagnesium compound (A-1) is 1 The molar composition ratio c / (α+β) of Y to all metal atoms is 0≦c / (α+β)≦2, and preferably 0≦c / (α+β)<1. 1 When the molar composition ratio of is 2 or less, the reactivity of the organomagnesium compound (A-1) with the titanium compound (A-2) tends to be improved.

[0063] Next, the titanium compound (A-2) will be described. (A-2) is a titanium compound represented by the following formula (2). (A-2): Ti(OR 7 ) d X 1 (4-d) ...(Formula 2) (In Equation 2, d is a real number between 0 and 4, and R 7 is a hydrocarbon group having 1 to 20 carbon atoms, and X 1 is a halogen atom.)

[0064] In the above formula 2, d is preferably 0 or more and 1 or less, and more preferably 0. In the above formula 2, R 7 Examples of the hydrocarbon group represented by the formula (I) include, but are not limited to, aliphatic hydrocarbon groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, 2-ethylhexyl, heptyl, octyl, decyl, and allyl groups; alicyclic hydrocarbon groups such as cyclohexyl, 2-methylcyclohexyl, and cyclopentyl groups; and aromatic hydrocarbon groups such as phenyl and naphthyl groups. Aliphatic hydrocarbon groups are particularly preferred. X 1 Examples of halogens represented by the formula (I) include chlorine, bromine, and iodine. Chlorine is particularly preferred. In this embodiment, titanium tetrachloride is particularly preferred as the titanium compound (A-2). In this embodiment, two or more compounds selected from the above can be used in combination.

[0065] Next, the reaction between the organomagnesium compound (A-1) and the titanium compound (A-2) will be described. The reaction is preferably carried out in an inert hydrocarbon solvent, more preferably in an aliphatic hydrocarbon solvent such as hexane or heptane. The molar ratio of the organomagnesium compound (A-1) to the titanium compound (A-2) in the reaction is not particularly limited, but the molar ratio of Ti atoms contained in (A-2) to Mg atoms contained in (A-1) (Ti / Mg) is preferably 0.1 to 10, more preferably 0.3 to 3. The reaction temperature is not particularly limited, but is preferably -80°C to 150°C, more preferably -40°C to 100°C. The order of addition of the organomagnesium compound (A-1) and the titanium compound (A-2) is not particularly limited, and any of the following methods is possible: adding (A-1) followed by (A-2), adding (A-2) followed by (A-1), or adding (A-1) and (A-2) simultaneously. However, the method of adding (A-1) and (A-2) simultaneously is preferred. In this embodiment, the solid catalyst component [A] obtained by the above reaction is used as a slurry solution using an inert hydrocarbon solvent.

[0066] Another example of the Ziegler-Natta catalyst component used in the present embodiment is preferably an olefin polymerization catalyst comprising a solid catalyst component [C] and an organometallic compound component [B], wherein the solid catalyst component [C] is produced by supporting an organomagnesium compound (C-4) soluble in an inert hydrocarbon solvent, represented by the following formula (5), and a titanium compound (C-5) represented by the following formula (6), on a support (C-3) prepared by reacting an organomagnesium compound (C-1) soluble in an inert hydrocarbon solvent, represented by the following formula (3), with a chlorinating agent (C-2) represented by the following formula (4).

[0067] (C-1):(M 2 )γ(Mg)δ(R 8 ) e (R 9 ) f (OR 10 ) g ...(Formula 3) (In formula 3, M 2is a metal atom belonging to the group consisting of groups 12, 13, and 14 of the periodic table, and R 8 , R 9 and R 10 are hydrocarbon groups having 2 to 20 carbon atoms, and γ, δ, e, f, and g are real numbers that satisfy the following relationships: 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 2 Represents the valence of .))

[0068] (C-2):H h SiCl i R 11 (4-(h+i)) ...(Formula 4) (In formula 4, R 11 is a hydrocarbon group having 1 to 12 carbon atoms, and h and i are real numbers that satisfy the following relationship: 0 <h、0<i、0<h+i≦4)

[0069] (C-4):(M 1 )α(Mg)β(R 2 ) a (R 3 ) b Y 1 c ...(Formula 5) (In formula 5, M 1 is a metal atom belonging to the group consisting of groups 12, 13, and 14 of the periodic table, and R 2 and R 3 is a hydrocarbon group having 2 to 20 carbon atoms, and Y 1 is alkoxy, siloxy, aryloxy, amino, amido, -N=CR 4 ,R 5 , -SR 6 (where R 4 , R 5 and R 6 represents a hydrocarbon group having 1 to 20 carbon atoms. When c is 2, Y 1 may be different from each other.) or a β-keto acid residue, and α, β, a, b, and c are real numbers that satisfy the following relationships: 0≦α, 0<β, 0≦a, 0≦b, 0≦c, 0 <a+b、0≦c / (α+β)≦2、nα+2β=a+b+c(ここで、nはM 1Represents the valence of .))

[0070] (C-5): Ti(OR 7 ) d X 1 (4-d) ...(Formula 6) (In Equation 6, d is a real number between 0 and 4, and R 7 is a hydrocarbon group having 1 to 20 carbon atoms, and X 1 is a halogen atom.)

[0071] First, the organomagnesium compound (C-1) will be described. (C-1) is shown in the form of an organomagnesium complex compound soluble in an inert hydrocarbon solvent, but it encompasses all dihydrocarbylmagnesium compounds and complexes of these compounds with other metal compounds. The relationship kγ+2δ=e+f+g between the symbols γ, δ, e, f, and g in the formula (3) above indicates the stoichiometry of the valence of the metal atom and the substituent.

[0072] In the above formula (3), R 8 Or R 9 The hydrocarbon group represented by is not particularly limited, but may be, for example, an alkyl group, a cycloalkyl group, or an aryl group, and specific examples thereof include methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, cyclohexyl, and phenyl groups. Particularly preferred are R 8 and R 9 are alkyl groups. When α>0, the metal atom M 2 As the metal atom, a metal atom belonging to the group consisting of Groups 12, 13 and 14 of the periodic table can be used, such as zinc, boron, aluminum, etc. Aluminum and zinc are particularly preferred.

[0073] metal atom M 2 The ratio δ / γ of magnesium to R is not particularly limited, but is preferably 0.1 or more and 30 or less, and more preferably 0.5 or more and 10 or less. When a predetermined organomagnesium compound with γ=0 is used, for example, R 8When R is 1-methylpropyl or the like, it is soluble in an inert hydrocarbon solvent, and such a compound also gives preferable results in this embodiment. 8 , R 9 is preferably one of the following three groups: (1), (2), and (3).

[0074] Group(1):R 8 , R 9 At least one of R is a secondary or tertiary alkyl group having 4 to 6 carbon atoms, and preferably R 8 , R 9 Both of these have 4 to 6 carbon atoms, and at least one of them is a secondary or tertiary alkyl group. Group(2):R 8 and R 9 and R are alkyl groups having different carbon numbers, preferably 8 is an alkyl group having 2 or 3 carbon atoms, and R 9 is an alkyl group having 4 or more carbon atoms. Group(3):R 8 , R 9 At least one of R is a hydrocarbon group having 6 or more carbon atoms, and preferably R 8 , R 9 The total number of carbon atoms contained in the alkyl group is 12 or more.

[0075] Specific examples of these groups are shown below. Examples of the secondary or tertiary alkyl group having 4 to 6 carbon atoms in group (1) include 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, 2-methylbutyl, 2-ethylpropyl, 2,2-dimethylpropyl, 2-methylpentyl, 2-ethylbutyl, 2,2-dimethylbutyl, and 2-methyl-2-ethylpropyl groups. The 1-methylpropyl group is particularly preferred.

[0076] In addition, in group (2), examples of the alkyl group having 2 or 3 carbon atoms include ethyl, 1-methylethyl, and propyl groups. In particular, an ethyl group is preferred. In addition, examples of the alkyl group having 4 or more carbon atoms include, but are not limited to, butyl, pentyl, hexyl, heptyl, and octyl groups. In particular, butyl and hexyl groups are preferred.

[0077] Furthermore, in group (3), the hydrocarbon group having 6 or more carbon atoms is not particularly limited, but examples thereof include hexyl, heptyl, octyl, nonyl, decyl, phenyl, 2-naphthyl groups, etc. Among the hydrocarbon groups, alkyl groups are preferred, and among the alkyl groups, hexyl and octyl groups are more preferred.

[0078] Generally, as the number of carbon atoms contained in the alkyl group increases, the compound tends to be more soluble in an inert hydrocarbon solvent, and the viscosity of the solution tends to increase. Therefore, it is preferable to use an alkyl group with a moderate chain length for ease of handling. The organomagnesium compound is used as an inert hydrocarbon solution, but it can be used without any problems even if a trace amount of Lewis basic compounds such as ethers, esters, and amines is contained or remains in the solution.

[0079] Next, the alkoxy group (OR 10 ) will be explained. R 10 The hydrocarbon group represented by R is preferably an alkyl group or aryl group having 1 to 12 carbon atoms, more preferably an alkyl group or aryl group having 3 to 10 carbon atoms. 10 Examples of the alkyl group include, but are not limited to, 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, naphthyl, etc. Particularly preferred are butyl, 1-methylpropyl, 2-methylpentyl, and 2-ethylhexyl groups.

[0080] The method for synthesizing the organomagnesium compound (C-1) is not particularly limited. 8 MgX 1 and formula: R 8 Mg(R 8 has the meaning mentioned above, and X 1 is a halogen atom.) and an organomagnesium compound of the formula: M 2 R 9 k and formula: M 2 R 9 (k-1) H(M 2 , R 9 and k has the same meaning as above) in an inert hydrocarbon solvent at a temperature of 25°C to 150°C, and if necessary, subsequently reacting with an organometallic compound belonging to the group consisting of R 9 (R 9 has the same meaning as above.) R soluble in an alcohol or an inert hydrocarbon solvent having a hydrocarbon group represented by 9 In another preferred method, the compound is reacted with an alkoxy magnesium compound having a hydrocarbon group represented by the following formula: and / or an alkoxy aluminum compound.

[0081] Among these, when an organomagnesium compound soluble in an inert hydrocarbon solvent is reacted with an alcohol, the order of the reaction is not particularly limited, and 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. The reaction ratio of the organomagnesium compound soluble in an inert hydrocarbon solvent and the alcohol is not particularly limited, but the molar composition ratio g / (γ+δ) of alkoxy groups to all metal atoms in the alkoxy group-containing organomagnesium compound obtained as a result of the reaction is preferably 0≦g / (γ+δ)≦2, and more preferably 0≦g / (γ+δ)<1.

[0082] Next, the chlorinating agent (C-2) will be described. The chlorinating agent (C-2) is a silicon chloride compound having at least one Si—H bond, represented by the following formula (4).

[0083] (C-2):H h SiCl i R 11 (4-(h+i)) ...(Formula 4) (In formula 4, R 11 is a hydrocarbon group having 1 to 12 carbon atoms, and h and i are real numbers that satisfy the following relationship: 0 <h、0<i、0<h+i≦4)

[0084] In the formula (4), R 11 The hydrocarbon group represented by the formula (I) is not particularly limited, but examples thereof include aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups, and specific examples include methyl, ethyl, propyl, 1-methylethyl, butyl, pentyl, hexyl, octyl, decyl, cyclohexyl, and phenyl groups. 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 preferred that i be 2 to 3.

[0085] These compounds (C-2) are not particularly limited, but examples thereof include HSiCl3, HSiCl2CH3, HSiCl2C2H5, HSiCl2(C3H7), HSiCl2(2-C3H7), HSiCl2(C4H9), HSiCl2(C6H5), HSiCl2(4-Cl-C6H4), HSiCl2(CH=CH2), HSiCl2(CH2C6H5), HSiCl2(1-C 10 Examples of silicon chloride compounds include HSiCl(CHCH=CH), HSiCl(CH), HSiCl(CH), HSiCl(CH), HSiCl(CH), HSiCl(CH), HSiCl(CH), HSiCl(CH), HSiCl(CH), HSiCl(CH)(2-CH), HSiCl(CH)(CH), HSiCl(CH). Silicon chloride compounds consisting of these compounds or mixtures of two or more selected from these compounds are used as (C-2). In particular, HSiCl, HSiClCH, HSiCl(CH), and HSiCl(CH) are preferred, with HSiCl and HSiClCH being more preferred.

[0086] Next, the reaction between the organomagnesium compound (C-1) and the chlorinating agent (C-2) will be explained. In the reaction, it is preferable to dilute (C-2) in advance with an inert hydrocarbon solvent, such as a chlorinated hydrocarbon such as 1,2-dichloroethane, o-dichlorobenzene, or dichloromethane; an ether medium such as diethyl ether or tetrahydrofuran; or a mixture thereof. Among these, an inert hydrocarbon solvent is more preferable in terms of catalyst performance. The reaction ratio of (C-1) and (C-2) is not particularly limited, but the ratio of silicon atoms contained in (C-2) to 1 mol of magnesium atoms contained in (C-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.

[0087] The reaction method of the organomagnesium compound (C-1) and the chlorinating agent (C-2) is not particularly limited, and any of the following methods can be used: a simultaneous addition method in which (C-1) and (C-2) are simultaneously introduced into a reactor and reacted; a method in which (C-2) is previously charged into a reactor and then (C-1) is introduced into the reactor; or a method in which (C-1) is previously charged into a reactor and then (C-2) is introduced into the reactor. Among these, the method in which (C-2) is previously charged into a reactor and then (C-1) is introduced into the reactor is preferred. The support (C-3) obtained by the above reaction is preferably separated by filtration or decantation, and then thoroughly washed with an inert hydrocarbon solvent to remove unreacted materials or by-products.

[0088] The reaction temperature between the organomagnesium compound (C-1) and the chlorinating agent (C-2) is not particularly limited, but 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. In the simultaneous addition method in which (C-1) and (C-2) are simultaneously introduced into a reactor and reacted, it is preferable to adjust the temperature of the reactor to a predetermined temperature in advance, and then adjust the temperature inside the reactor to the predetermined temperature while performing the simultaneous addition, thereby adjusting the reaction temperature to the predetermined temperature. In the method of charging (C-2) into a reactor in advance and then introducing (C-1) into the reactor, it is preferable to adjust the reaction temperature to a predetermined temperature by adjusting the temperature of the reactor into which the silicon chloride compound has been charged to a predetermined temperature, and then adjusting the temperature inside the reactor to a predetermined temperature while introducing the organomagnesium compound into the reactor. In the method of charging (C-1) into a reactor in advance and then introducing (C-2) into the reactor, it is preferable to adjust the temperature of the reactor into which (C-1) has been charged to a predetermined temperature, and then adjust the temperature inside the reactor to a predetermined temperature while introducing (C-2) into the reactor, thereby adjusting the reaction temperature to a predetermined temperature.

[0089] Next, the organomagnesium compound (C-4) will be explained. As (C-4), a compound represented by the following formula 5: (C-4) is preferred.

[0090] (C-4):(M 1 )α(Mg)β(R 2 ) a (R 3 ) b Y 1 c ...(Formula 5) (In formula 5, M 1 is a metal atom belonging to the group consisting of groups 12, 13, and 14 of the periodic table, and R 2 and R 3 is a hydrocarbon group having 2 to 20 carbon atoms, and Y 1 is alkoxy, siloxy, aryloxy, amino, amido, -N=CR 4 ,R 5 , -SR 6 (where R 4 , R 5 and R 6 represents a hydrocarbon group having 1 to 20 carbon atoms. When c is 2, Y 1may be different from each other.) or a β-keto acid residue, and α, β, a, b, and c are real numbers that satisfy the following relationships: 0≦α, 0<β, 0≦a, 0≦b, 0 <a+b、0≦c / (α+β)≦2、nα+2β=a+b+c(ここで、nはM 1 Represents the valence of .))

[0091] The amount of the organic magnesium compound (C-4) used is preferably such that the molar ratio of magnesium atoms contained in (C-4) to titanium atoms contained in the titanium compound (C-5) is 0.1 or more and 10 or less, more preferably 0.5 or more and 5 or less.

[0092] The temperature for the reaction of the organomagnesium compound (C-4) with the titanium compound (C-5) is not particularly limited, but is preferably in the range of -80°C or higher and 150°C or lower, and more preferably in the range of -40°C or higher and 100°C or lower.

[0093] The concentration of the organomagnesium compound (C-4) when used is not particularly limited, but is preferably 0.1 mol / L or more and 2 mol / L or less, and more preferably 0.5 mol / L or more and 1.5 mol / L or less, based on the titanium atoms contained in (C-4). Note that an inert hydrocarbon solvent is preferably used to dilute (C-4).

[0094] The order of addition of the organomagnesium compound (C-4) and the titanium compound (C-5) to the support (C-3) is not particularly limited. It is possible to add (C-4) followed by (C-5), to add (C-5) followed by (C-4), or to add (C-4) and (C-5) simultaneously. Among these, the simultaneous addition of (C-4) and (C-5) is preferred. The reaction between (C-4) and (C-5) is carried out in an inert hydrocarbon solvent, preferably an aliphatic hydrocarbon solvent such as hexane or heptane. The catalyst thus obtained is used as a slurry solution in an inert hydrocarbon solvent.

[0095] Next, the titanium compound (C-5) will be described. In this embodiment, (C-5) is a titanium compound represented by the following formula (6).

[0096] (C-5): Ti(OR 7 ) d X 1 (4-d) ...(Formula 6) (In Equation 6, d is a real number between 0 and 4, and R 7 is a hydrocarbon group having 1 to 20 carbon atoms, and X 1 is a halogen atom.)

[0097] In (Equation 6), R 7 The hydrocarbon group represented by the formula (I) is not particularly limited, but examples thereof include aliphatic hydrocarbon groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, 2-ethylhexyl, heptyl, octyl, decyl, and allyl groups; alicyclic hydrocarbon groups such as cyclohexyl, 2-methylcyclohexyl, and cyclopentyl groups; and aromatic hydrocarbon groups such as phenyl and naphthyl groups. Among these, aliphatic hydrocarbon groups are preferred. 1 The halogen represented by the formula (C-5) is not particularly limited, but examples thereof include chlorine, bromine, and iodine. Among these, chlorine is preferred. The titanium compound (C-5) selected from the above may be used alone or in combination of two or more.

[0098] The amount of titanium compound (C-5) used is not particularly limited, but is preferably 0.01 to 20, particularly preferably 0.05 to 10, in terms of molar ratio to magnesium atoms contained in the support (C-3).

[0099] The reaction temperature of the titanium compound (C-5) is not particularly limited, but is preferably in the range of -80°C or higher and 150°C or lower, more preferably in the range of -40°C or higher and 100°C or lower. The method for supporting the titanium compound (C-5) on the support (C-3) is not particularly limited. A method of reacting an excess of (C-5) with (C-3) or a method of efficiently supporting (C-5) by using a third component may be used, but a method of supporting (C-5) by reacting (C-5) with an organomagnesium compound (C-4) is preferred.

[0100] Next, the organometallic compound component [B] that constitutes the Ziegler-Natta catalyst used in the production of the ethylene polymer that constitutes the polyethylene resin composition of the present embodiment will be described. The solid catalyst component [C] becomes a highly active polymerization catalyst when combined with the organometallic compound component [B]. The organometallic compound component [B] is sometimes called a “co-catalyst.” The organometallic compound component [B] is preferably a compound containing a metal belonging to Groups 1, 2, 12, and 13 of the periodic table, and is particularly preferably an organoaluminum compound and / or an organomagnesium compound.

[0101] As the organoaluminum compound as the organometallic compound component [B], it is preferable to use the compounds represented by the following formula (7) alone or in combination.

[0102] AlR 12 j Z 1 (3-j) ...(Formula 7) (In formula 7, R 12 is a hydrocarbon group having 1 to 20 carbon atoms, Z 1 is a group consisting of hydrogen, halogen, alkoxy, aryloxy, and siloxy groups, and j is a number between 2 and 3.

[0103] In the above (Equation 7), R 12The hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) is not particularly limited, but includes, for example, aliphatic hydrocarbons, aromatic hydrocarbons, and alicyclic hydrocarbons. For example, trialkylaluminums 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 are preferred. In particular, trialkylaluminum compounds are more preferred.

[0104] As the organomagnesium compound as the organometallic compound component [B], organomagnesium compounds soluble in inert hydrocarbon solvents such as those represented by the above and following formula (3) are preferred.

[0105] (M 2 )γ(Mg)δ(R 8 ) e (R 9 ) f (OR 10 ) g ...(Formula 3) (In formula 3, M 2 is a metal atom belonging to the group consisting of groups 12, 13, and 14 of the periodic table, and R 8 , R 9 and R 10are hydrocarbon groups having 2 to 20 carbon atoms, and γ, δ, e, f, and g are real numbers that satisfy the following relationships: 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 2 Represents the valence of .))

[0106] This organomagnesium compound is shown in the form of an organomagnesium complex compound soluble in an inert hydrocarbon solvent, but it also includes dialkylmagnesium compounds and complexes of these compounds with other metal compounds. 2 , R 8 , R 9 , OR 10 As already mentioned, it is preferable that the organomagnesium compound has high solubility in an inert hydrocarbon solvent, and therefore, δ / γ is preferably in the range of 0.5 to 10. 2 More preferred are compounds in which is aluminum. The combination ratio of the solid catalyst component and the organometallic compound component [B] is not particularly limited, but it is preferable that the organometallic compound component [B] is 1 mmol or more and 3,000 mmol or less per 1 g of the solid catalyst component.

[0107] <Metallocene catalyst> As the metallocene catalyst, a general transition metal compound is used. There are no particular limitations on the method for producing a metallocene catalyst, and examples thereof include the method described in Japanese Patent No. 4868853. Such metallocene catalysts are composed of two catalytic components: (a) a transition metal compound having a cyclic η-bonding anionic ligand, and (b) an activator capable of reacting with the transition metal compound to form a complex that exhibits catalytic activity.

[0108] The (a) transition metal compound having a cyclic η-bonding anionic ligand can be represented, for example, by the following formula (8). L 1 j W k M 3 X2 p X 3 q ...(Formula 8)

[0109] In the above (Equation 8), L 1 each independently represent an η-bonding 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 optionally has 1 to 8 substituents, each of which is independently a substituent having up to 20 non-hydrogen 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 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.

[0110] In the formula (8), M 3 is 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 metal having at least one ligand L 1 η 5 Represents a bonded transition metal.

[0111] In the formula (8), W is a divalent substituent having up to 50 non-hydrogen atoms, and L 1 and M 3 Each bond has a valence of 1, resulting in L 1 and M 3 represents a divalent substituent that cooperates with X to form a metallocycle; 2 are each independently a monovalent anionic σ-bonded ligand, M 3 a divalent anionic σ-bonded ligand that is divalently bonded to L, and 1 and M 3and a divalent anionic σ-bonded ligand having up to 60 non-hydrogen atoms, the divalent anionic σ-bonded ligand being bonded to each of the anionic σ-bonded ligands with a valence of 1.

[0112] In the formula (8), X 2 each independently represents a neutral Lewis base coordinating compound having up to 40 non-hydrogen atoms; X 3 represents a neutral Lewis base coordinating compound.

[0113] j is 1 or 2, provided that when j is 2, two ligands L 1 may be bonded to each other via a divalent group having up to 20 non-hydrogen atoms, and the divalent group is a group selected from the group consisting of hydrocarbadiyl groups having 1 to 20 carbon atoms, halohydrocarbadiyl groups having 1 to 12 carbon atoms, hydrocarbyleneoxy groups having 1 to 12 carbon atoms, hydrocarbyleneamino groups having 1 to 12 carbon atoms, silanediyl groups, halosilanediyl groups, and silyleneamino groups.

[0114] k is 0 or 1, and p is 0, 1, or 2, provided that X 2 is a monovalent anionic σ-bonded ligand, or L 1 and M 3 If p is a divalent anionic σ-bonded ligand bound to M 3 is an integer that is one or more smaller than the formal oxidation number of X 2 M 3 If the ligand is a divalent anionic σ-bonded ligand bound only to M, then p is M 3 is an integer that is (j+1) or more less than the formal oxidation number of , and q is 0, 1, or 2.

[0115] The ligand X in the compound of formula 8 2 Examples of the alkyl group include 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 phosphate groups having 1 to 60 carbon atoms, hydrocarbyl sulfide groups having 1 to 60 carbon atoms, silyl groups, and composite groups thereof.

[0116] The neutral Lewis base coordinating compound X in the compound of formula (8) 3 Examples of the alkyl group include phosphines, ethers, amines, olefins having 2 to 40 carbon atoms, dienes having 1 to 40 carbon atoms, and divalent groups derived from these compounds.

[0117] The transition metal compound having the (a) cyclic η-bonding anionic ligand constituting the metallocene catalyst is preferably a transition metal compound represented by the formula (8) (where j = 1). A preferred example of the compound represented by the formula (8) (where j = 1) is a compound represented by the following formula (9).

[0118] [ka]

[0119] In the formula (9), M 4 R represents a transition metal selected from the group consisting of titanium, zirconium, nickel, and hafnium, and has a formal oxidation state of +2, +3, or +4. 13 each independently represents a substituent having up to 20 non-hydrogen atoms selected from the group consisting of a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, a silyl group, a germyl group, a cyano group, a halogen atom, and a composite group thereof, provided that the substituent R 13 is a hydrocarbon group having 1 to 8 carbon atoms, a silyl group, or a germyl group, two adjacent substituents R 13 are bonded to each other to form a divalent group, whereby the two adjacent substituents R 13 can cooperate with the bonds between the two carbon atoms of the cyclopentadienyl ring to form a ring.

[0120] In the formula (9), X 4each independently represents a substituent having up 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 hydrocarbyl phosphate group having 1 to 18 carbon atoms, a hydrocarbyl sulfide group having 1 to 18 carbon atoms, and a composite group thereof, provided that in some cases two substituents X 4 can cooperate to form a neutral conjugated diene or divalent group having 4 to 30 carbon atoms.

[0121] In the formula (9), Y 2 -O-, -S-, -NR * -or-PR * -, where R * 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.

[0122] In the formula (9), Z 2 is SiR * 2. CR * 2. SiR * 2SiR * 2. CR * 2CR *2 , C.R. * =CR * , C.R. * 2SiR * 2 or GeR * 2, where R * is as defined above and n is 1, 2 or 3.

[0123] Examples of the (a) transition metal compound having a cyclic η-bonding anionic ligand that constitutes the metallocene catalyst used in the production of the ethylene polymer that constitutes the polyethylene resin composition of the present embodiment include the compounds shown below. The zirconium compound is not particularly limited, and examples thereof include bis(methylcyclopentadienyl)zirconium dimethyl, bis(n-butylcyclopentadienyl)zirconium dimethyl, bis(indenyl)zirconium dimethyl, bis(1,3-dimethylcyclopentadienyl)zirconium dimethyl, (pentamethylcyclopentadienyl)(cyclopentadienyl)zirconium dimethyl, bis(cyclopentadienyl)zirconium dimethyl, bis(pentamethylcyclopentadienyl)zirconium dimethyl, bis(fluorenyl)zirconium dimethyl, ethylene bis(indenyl)zirconium dimethyl, ethylene bis(4,5,6,7-tetrahydro-1-indenyl)zirconium dimethyl, ethylene bis(4-methyl-1-indenyl)zirconium dimethyl, and ethylene bis(5-methyl-1-indenyl)zirconium dimethyl. 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, ethylene bis(4,7-dimethoxy-1-indenyl)zirconium dimethyl, methylene bis(cyclopentadienyl)zirconium dimethyl, isopropylidene(cyclopentadienyl)zirconium dimethyl, isopropylidene(cyclopentadienyl-fluorenyl)zirconium dimethyl, silylene bis(cyclopentadienyl)zirconium dimethyl, dimethylsilylene(cyclopentadienyl)zirconium dimethyl, and the like.

[0124] The titanium-based compound is not particularly limited, but for example, [(Nt-butylamido)(tetramethyl-η 5 -cyclopentadienyl)-1,2-ethanediyl]titanium dimethyl, [(Nt-butylamido)(tetramethyl-η 5 -cyclopentadienyl)dimethylsilane]titanium dimethyl, [(N-methylamido)(tetramethyl-η 5-cyclopentadienyl)dimethylsilane]titanium dimethyl, [(N-phenylamido)(tetramethyl-η 5 -cyclopentadienyl)dimethylsilane]titanium dimethyl, [(N-benzylamido)(tetramethyl-η 5 -cyclopentadienyl)dimethylsilane]titanium dimethyl, [(Nt-butylamido)(η 5 -cyclopentadienyl)-1,2-ethanediyl]titanium dimethyl, [(Nt-butylamido)(η 5 -cyclopentadienyl)dimethylsilane]titanium dimethyl, [(N-methylamido)(η 5 -cyclopentadienyl)-1,2-ethanediyl]titanium dimethyl, [(N-methylamido)(η 5 -cyclopentadienyl)dimethylsilane]titanium dimethyl, [(Nt-butylamido)(η 5 -indenyl)dimethylsilane]titanium dimethyl, [(N-benzylamide)(η 5 -indenyl)dimethylsilane]titanium dimethyl, and the like.

[0125] The nickel-based compound is not particularly limited, but examples thereof include dibromobistriphenylphosphine nickel, dichlorobistriphenylphosphine nickel, dibromodiacetonitrile nickel, dibromodibenzonitrile nickel, dibromo(1,2-bisdiphenylphosphinoethane)nickel, dibromo(1,3-bisdiphenylphosphinopropane)nickel, dibromo(1,1'-diphenylbisphosphinoferrocene)nickel, dimethylbisdiphenylphosphine nickel, and dimethyl(1,2-bisdiphenylphosphinoethane)nickel. methyl(1,2-bisdiphenylphosphinoethane)nickel tetrafluoroborate, (2-diphenylphosphino-1-phenylethyleneoxy)phenylpyridine nickel, dichlorobistriphenylphosphine palladium, dichlorodibenzonitrile palladium, dichlorodiacetonitrile palladium, dichloro(1,2-bisdiphenylphosphinoethane)palladium, bistriphenylphosphine palladium bistetrafluoroborate, bis(2,2'-bipyridine)methyliron tetrafluoroborate etherate, and the like.

[0126] The hafnium-based compound is not particularly limited, but examples thereof include [(Nt-butylamido)(tetramethyl-η 5 -cyclopentadienyl)-1,2-ethanediyl]hafnium dimethyl, [(Nt-butylamido)(tetramethyl-η 5 -cyclopentadienyl)dimethylsilane]hafnium dimethyl, [(N-methylamido)(tetramethyl-η 5 -cyclopentadienyl)dimethylsilane]hafnium dimethyl, [(N-phenylamido)(tetramethyl-η 5 -cyclopentadienyl)dimethylsilane]hafnium dimethyl, [(N-benzylamido)(tetramethyl-η 5 -cyclopentadienyl)dimethylsilane]hafnium dimethyl, [(Nt-butylamido)(η 5 -cyclopentadienyl)-1,2-ethanediyl]hafnium dimethyl, [(Nt-butylamido)(η 5-cyclopentadienyl)dimethylsilane]hafnium dimethyl, [(N-methylamido)(η 5 -cyclopentadienyl)-1,2-ethanediyl]hafnium dimethyl, [(N-methylamido)(η 5 -cyclopentadienyl)dimethylsilane]hafnium dimethyl, [(Nt-butylamido)(η 5 -indenyl)dimethylsilane]hafnium dimethyl, [(N-benzylamide)(η 5 -indenyl)dimethylsilane]hafnium dimethyl and the like.

[0127] The (a) transition metal compound having a cyclic η-bonding anionic ligand, which constitutes the metallocene catalyst used in the production of the ethylene polymer constituting the polyethylene resin composition of the present embodiment, further includes the "dimethyl" portion of the name of each of the zirconium-based compounds and titanium-based compounds described above (this appears immediately after the final portion of the name of each compound, i.e., "zirconium" or "titanium" portion, and is represented by X in the formula 2). 4 (the name corresponding to the part of the formula) can be used, for example, to refer to "dichloro", "dibromide", "diiodide", "diethyl", "dibutyl", "diphenyl", "dibenzyl", "2-(N,N-dimethylamino)benzyl", "2-butene-1,4-diyl", "s-trans-η4-1,4-diphenyl-1,3-butadiene", "s-trans-η 4 -3-methyl-1,3-pentadiene", "s-trans-η 4 -1,4-dibenzyl-1,3-butadiene", "s-trans-η 4 -2,4-hexadiene", "s-trans-η 4 -1,3-pentadiene", "s-trans-η 4 -1,4-ditolyl-1,3-butadiene", "s-trans-η 4 -1,4-bis(trimethylsilyl)-1,3-butadiene," "s-cis-η 4 -1,4-diphenyl-1,3-butadiene", "s-cis-η 4 -3-methyl-1,3-pentadiene", "s-cis-η 4-1,4-dibenzyl-1,3-butadiene", "s-cis-η 4 -2,4-hexadiene", "s-cis-η 4 -1,3-pentadiene", "s-cis-η 4 -1,4-ditolyl-1,3-butadiene", "s-cis-η 4 Also included are compounds with names that can be replaced with any other name, such as "-1,4-bis(trimethylsilyl)-1,3-butadiene."

[0128] The transition metal compound (a) having a cyclic η-bonding anionic ligand, which constitutes the metallocene catalyst used in the production of the ethylene polymer constituting the polyethylene resin composition of the present embodiment, can be synthesized by a generally known method. In the present embodiment, these transition metal compounds may be used alone or in combination.

[0129] Next, the “(b) activator capable of reacting with a transition metal compound to form a complex that exhibits catalytic activity (hereinafter also simply referred to as “activator”)” used in the production of the ethylene polymer constituting the polyethylene resin composition of the present embodiment will be described. The activator includes, for example, a compound defined by the following formula 10. [L 2 -H] d+ [M 5 m Q p ] d- ...(Equation 10) (In formula 10, [L 2 -H] d+ represents a proton-donating Bronsted acid, where L 2 represents a neutral Lewis base, d is an integer of 1 to 7; [M 5 m Q p ] d- represents a compatible non-coordinating anion, where M 5represents a metal or metalloid belonging to any of Groups 5 to 15 of the periodic table, and each Q is independently selected from the group consisting of hydride, halide, dihydrocarbylamide group having 2 to 20 carbon atoms, hydrocarbyloxy group having 1 to 30 carbon atoms, hydrocarbon group having 1 to 30 carbon atoms, and substituted hydrocarbon group having 1 to 40 carbon atoms, wherein the number of Q that is a halide is 1 or less, m is an integer of 1 to 7, p is an integer of 2 to 14, d is as defined above, and pm=d.

[0130] The non-coordinating anion is not particularly limited, and examples thereof include 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-trifluorimethylphenyl)(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)(

[0033] Examples of such borate include tris(pentafluorophenyl)(hydroxyphenyl)borate, tris(pentafluorophenyl)(hydroxyphenyl)borate, tris(2,4-dimethylphenyl)(hydroxyphenyl)borate, tris(3,5-dimethylphenyl)(hydroxyphenyl)borate, tris(3,5-di-trifluorimethylphenyl)(hydroxyphenyl)borate, tris(pentafluorophenyl)(2-hydroxyethyl)borate, tris(pentafluorophenyl)(4-hydroxybutyl)borate, tris(pentafluorophenyl)(4-hydroxycyclohexyl)borate, tris(pentafluorophenyl)(4-(4'-hydroxyphenyl)phenyl)borate, and tris(pentafluorophenyl)(6-hydroxy-2-naphthyl)borate.

[0131] Other preferred non-coordinating anions include borates in which the hydroxy group of the above-exemplified borates is replaced with an NHR group, where R is preferably a methyl group, an ethyl group, or a tert-butyl group.

[0132] Furthermore, the proton-donating Bronsted acid is not particularly limited, and examples thereof include trialkyl group-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; dialkylammonium cations such as di-(i-propyl)ammonium and dicyclohexylammonium; triarylphosphonium cations such as triphenylphosphonium, tri(methylphenyl)phosphonium, and tri(dimethylphenyl)phosphonium; and dimethylsulfonium, diethylsulfonium, and diphenylsulfonium.

[0133] Furthermore, as the activator used in the production of the ethylene polymer constituting the polyethylene resin composition of the present embodiment, an organometallic oxy compound having a unit represented by the following formula 11 can also be used.

[0134] [ka]

[0135] (where M 6 is a metal or metalloid of Groups 13 to 15 of the periodic table, and R 14 are each independently a hydrocarbon group or a substituted hydrocarbon group having 1 to 12 carbon atoms, and n is a metal M 6 where m is an integer of 2 or greater.)

[0136] A preferred example of the activator used in the production of the ethylene polymer constituting the polyethylene resin composition of the present embodiment is, for example, an organoaluminum oxy compound containing a unit represented by the following formula (12).

[0137] [ka]

[0138] (where R 15 is an alkyl group having 1 to 8 carbon atoms, and m is an integer of 2 to 60.

[0139] A more preferred example of the activator used in producing the ethylene polymer that constitutes the polyethylene resin composition of the present embodiment is methylalumoxane containing a unit represented by the following formula (13).

[0140] [ka]

[0141] (where m is an integer from 2 to 60.)

[0142] In this embodiment, the activator component may be used alone or in combination of two or more.

[0143] In the production of the ethylene polymer constituting the polyethylene resin composition of this embodiment, these catalyst components can also be used as supported catalysts by being supported on a solid component. Such solid components are not particularly limited, but specific examples include at least one inorganic solid material selected from the group consisting of porous polymer materials such as polyethylene, polypropylene, and styrene-divinylbenzene copolymers; inorganic solid materials of elements in Groups 2, 3, 4, 13, and 14 of the Periodic Table, such as silica, alumina, magnesia, magnesium chloride, zirconia, titania, boron oxide, calcium oxide, zinc oxide, barium oxide, vanadium pentoxide, chromium oxide, and thorium oxide, and mixtures thereof; and double oxides thereof.

[0144] The silica composite oxide is not particularly limited, but examples thereof include composite oxides of silica and an element of Group 2 or Group 13 of the periodic table, such as silica magnesia and silica alumina. In addition to the above two catalyst components, in this embodiment, an organoaluminum compound can be used as a catalyst component as needed. An example of an organoaluminum compound that can be used in this embodiment is a compound represented by the following formula (14).

[0145] [ka]

[0146] (where R 16 is an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 20 carbon atoms, and X 5 is a halogen, hydrogen or an alkoxyl group, the alkyl group is linear, branched or cyclic, and n is an integer of 1 to 3.

[0147] The organoaluminum compound serving as the catalyst component may be a mixture of compounds represented by the formula 14. Examples of the organoaluminum compound include those represented by the formula 14, where R 16 is a methyl group, an ethyl group, a butyl group, an isobutyl group, a hexyl group, an octyl group, a decyl group, a phenyl group, a tolyl group, or the like; 5 is a methoxy group, an ethoxy group, a butoxy group, a chlorine group, etc.

[0148] In the present embodiment, the organoaluminum compound that can be used as the catalyst component is not particularly limited, but examples thereof include trimethylaluminum, triethylaluminum, tributylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, and the like, as well as reaction products of these organoaluminum compounds with alcohols such as methyl alcohol, ethyl alcohol, butyl alcohol, pentyl alcohol, hexyl alcohol, octyl alcohol, and decyl alcohol, such as dimethylmethoxyaluminum, diethylethoxyaluminum, and dibutylbutoxyaluminum.

[0149] The ethylene-based polymer constituting the polyethylene resin composition of the present embodiment can be polymerized by suspension polymerization or gas phase polymerization, in which ethylene or a monomer containing ethylene is (co)polymerized. Among these, suspension polymerization is preferred because it can efficiently remove heat generated by polymerization. In suspension polymerization, an inert hydrocarbon medium can be used as the medium, and the olefin itself can also be used as the solvent.

[0150] Such inert hydrocarbon medium is not particularly limited, but examples thereof 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; and mixtures thereof.

[0151] (Polymerization conditions) The polymerization temperature in the method for producing the ethylene polymer contained in the polyethylene resin composition of the present embodiment is usually 30°C or higher and 100°C or lower. A polymerization temperature of 30°C or higher tends to enable more efficient industrial production, while a polymerization temperature of 100°C or lower tends to enable more stable continuous operation.

[0152] Furthermore, the polymerization pressure in the method for producing the polyethylene polymer contained in the polyethylene resin composition of this embodiment is usually atmospheric pressure or higher and 2 MPa or lower. The polymerization pressure is preferably 0.1 MPa or higher, more preferably 0.12 MPa or higher, and is preferably 1.5 MPa or lower, more preferably 1.0 MPa or lower. A polymerization pressure of atmospheric pressure or higher tends to enable more efficient industrial production, while a polymerization pressure of 2 MPa or lower tends to suppress partial heat generation due to a rapid polymerization reaction when the catalyst is introduced, and to enable stable production of polyethylene.

[0153] The polymerization reaction can be carried out in any of batch, semi-continuous, and continuous modes, but continuous polymerization is preferred. Continuously supplying ethylene gas, solvent, catalyst, etc. to the polymerization system and continuously discharging them together with the produced polyethylene makes it possible to suppress localized high-temperature conditions caused by a sudden ethylene reaction, thereby further stabilizing the polymerization system. When ethylene reacts in a homogeneous system, the formation of branches, double bonds, etc. in the polymer chain is suppressed, making it less likely that polyethylene will become low-molecular-weight or crosslinked. This reduces the amount of unmelted material remaining when the ultra-high molecular weight polyethylene powder is melted or dissolved, suppressing coloration and reducing the occurrence of problems such as a decrease in mechanical properties. Therefore, a continuous polymerization system, which produces a more homogeneous system, is preferred.

[0154] It is also possible to carry out the polymerization in two or more stages with different reaction conditions. Furthermore, as described in, for example, West German Patent Application Publication No. 3127133, the intrinsic viscosity of the resulting polyethylene may be controlled by adding hydrogen to the polymerization system or by changing the polymerization temperature. Specifically, the intrinsic viscosity can be controlled within an appropriate range by adding hydrogen as a chain transfer agent to the polymerization system. When hydrogen is added to the polymerization system, the molar fraction of hydrogen is preferably 0 mol% or more and 30 mol% or less, more preferably 0 mol% or more and 25 mol% or less, and even more preferably 0 mol% or more and 20 mol% or less. In addition to the components described above, this embodiment may also contain other known components useful for the production of polyethylene.

[0155] When polymerizing the ethylene polymer constituting the polyethylene resin composition of this embodiment, it is preferable to use an antistatic agent such as Stadis 450 manufactured by The Associated Octel Company (distributor: Maruwa Bussan) to suppress adhesion of the polymer to the polymerization reactor. Stadis 450 can be diluted in an inert hydrocarbon medium and added to the polymerization reactor by a pump or the like. The amount added is preferably in the range of 0.10 ppm to 20 ppm, more preferably 0.20 ppm to 10 ppm, relative to the amount of ethylene polymer produced per unit time.

[0156] In the method for producing the ethylene polymer contained in the polyethylene resin composition of this embodiment, it is preferable to adjust the temperature of the catalyst introduced into the reactor to less than 5°C. It is also preferable to introduce hexane having ethylene dissolved therein through a hexane feed port into the reactor at a temperature of less than 5°C, and to introduce the remaining ethylene through an ethylene feed port. It is also preferable to provide the catalyst feed port, ethylene feed port, and hexane feed port having ethylene dissolved therein all at the bottom of the reactor, and introduce them all into the reactor simultaneously.

[0157] (additives) To the ethylene polymer contained in the polyethylene resin composition of the present embodiment, additives such as a slip agent, a neutralizing agent, an antioxidant, a light resistance stabilizer, an antistatic agent, and a pigment may be added as needed.

[0158] The slip agent or neutralizing agent is not particularly limited, but examples thereof 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. The content of the slip agent or neutralizing agent is not particularly limited, but is preferably 5000 ppm or less, more preferably 4000 ppm or less, and even more preferably 3000 ppm or less.

[0159] The antioxidant is not particularly limited, but for example, a phenol-based compound or a phenol-phosphate-based compound is preferable. Specific examples include phenolic antioxidants such as 2,6-di-t-butyl-4-methylphenol (dibutylhydroxytoluene), n-octadecyl-3-(4-hydroxy-3,5-di-t-butylphenyl)propionate, and tetrakis(methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate))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]dioxaphosphepine; and phosphorus-based 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-butylphenylphosphite).

[0160] In the ethylene polymer contained in the polyethylene resin composition of the present embodiment, the amount of antioxidant is preferably 5 parts by mass or less, more preferably 4 parts by mass or less, even more preferably 3 parts by mass or less, and still more preferably 2 parts by mass or less, relative to 100 parts by mass of the total of the polyethylene resin composition and liquid paraffin. When the amount of antioxidant is 5 parts by mass or less, deterioration of the polyethylene is suppressed, and embrittlement, discoloration, deterioration of mechanical properties, etc. are less likely to occur, resulting in more excellent long-term stability.

[0161] The light resistance stabilizer is not particularly limited, but examples thereof include benzotriazole-based light resistance 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 resistance 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}]. The content of the light resistance stabilizer is not particularly limited, but is preferably 5000 ppm or less, more preferably 3000 ppm or less, and even more preferably 2000 ppm or less.

[0162] The antistatic agent is not particularly limited, but examples thereof include aluminosilicate, kaolin, clay, natural silica, synthetic silica, silicates, talc, diatomaceous earth, and glycerin fatty acid esters.

[0163] [Uses of polyethylene resin composition] The polyethylene resin composition of the present embodiment can be used for various applications, such as a microporous membrane for a separator of a secondary battery, particularly a microporous membrane for a separator of a lithium-ion secondary battery, a sintered body, a high-strength fiber, and the like. The microporous membrane can be produced by a wet method using a solvent, which involves extrusion, stretching, extraction, and drying using an extruder equipped with a T-die. Taking advantage of the excellent properties of high-molecular-weight ethylene polymers, such as abrasion resistance, high tribological properties, high strength, and high impact resistance, the membrane can also be used for molded articles obtained by sintering ethylene polymers. [Example]

[0164] Hereinafter, the present embodiment will be described in more detail with reference to specific examples and comparative examples, but the present invention is not limited to the following examples and comparative examples.

[0165] [Measurement method and conditions] The physical properties of the polyethylene resin compositions of the examples and comparative examples were measured by the following methods.

[0166] (1) Molecular weight measurement The polyethylene resin composition and the extracted components obtained in (3) described below were used as measurement samples. 15 mL of o-dichlorobenzene was added to 20 mg of the measurement sample, and the mixture was stirred at 150°C for 1 hour to prepare a sample solution. Gel permeation chromatography (GPC) measurements were performed under the following conditions. From the measurement results, the number average molecular weight (Mn), weight average molecular weight (Mw), and molecular weight distribution (Mw / Mn) were determined based on a calibration curve prepared using commercially available monodisperse polystyrene. Apparatus: Waters 150-C ALC / GPC Detector: RI detector Mobile phase: o-dichlorobenzene (for high-performance liquid chromatography) ·Flow rate: 1.0mL / min Column: One Shodex AT-807S and two Tosoh TSK-gel GMH-H6 columns were connected together. Column temperature: 140℃

[0167] (2) CFC elution amount (TREF elution amount) <Condition 1> The extracted components obtained in (3) described below were used as measurement samples, and cross fractionation chromatography (CFC) measurements were performed on an o-dichlorobenzene solution of the measurement sample. The elution temperature-elution amount curve was measured as follows, and the elution amount at each temperature, the temperature (°C) at which the CFC elution amount reached its maximum, and the temperature (°C) at which the integrated elution amount in the CFC measurement reached 10% by mass were determined. First, the column containing the packing material was heated to 140°C, and a sample solution prepared by dissolving the measurement sample in o-dichlorobenzene was introduced and maintained for 120 minutes. Next, the temperature of the column was lowered to 40°C at a rate of 0.5°C / min and then held at that temperature for 20 minutes to allow the sample to precipitate on the surface of the packing material.

[0168] Thereafter, the temperature of the column was gradually increased at a rate of 20°C / min. The temperature was first raised from 40°C to 60°C at 10°C intervals, then from 60°C to 69°C at 3°C intervals, then from 69°C to 100°C at 1°C intervals, and finally from 100°C to 120°C at 10°C intervals. Each temperature was maintained for 21 minutes, and then the temperature was raised again. The concentration of the sample (ethylene polymer) eluted at each temperature was detected. An elution temperature-elution amount curve was then measured from the elution amount (mass%) of the sample (ethylene polymer) and the temperature (°C) in the column at that time. The elution amount, integrated elution amount, temperature (°C) at which the elution amount in the CFC measurement reached a maximum, and temperature (°C) at which the integrated elution amount in the CFC measurement reached 10% by mass were determined. Equipment: Polymer ChAR Automated 3D analyzer CFC-2 Column: Stainless steel microball column (3 / 8" od x 150mm) Eluent: o-dichlorobenzene (for high-performance liquid chromatography) Sample solution concentration: 20 mg of sample (ethylene polymer) / 20 mL of o-dichlorobenzene ·Injection volume: 0.5mL Pump flow rate: 1.0 mL / min Detector: Polymer ChAR infrared spectrophotometer IR4 Detection wave number: 3.42 μm Sample dissolution conditions: 140℃ x 120min dissolution

[0169] <Condition 2> A polyethylene resin composition was used as a measurement sample, and the elution temperature-elution amount curve of the measurement sample was measured by temperature rising elution fractionation (TREF) as follows. The elution amount at each temperature, the integrated elution amount, and the temperature (°C) at which the elution amount in the CFC measurement reached its maximum value (Max) were determined, and the number of peaks in the CFC measurement was calculated. First, the column containing the packing material was heated to 140°C, and a sample solution prepared by dissolving the measurement sample in o-dichlorobenzene was introduced and maintained at this temperature for 120 minutes. Next, the column temperature was lowered to 40°C at a rate of 0.5°C / min and maintained at this temperature for 20 minutes to allow the sample to precipitate on the packing material surface.

[0170] Thereafter, the temperature of the column was gradually increased at a rate of 20°C / min. The temperature was first raised from 40°C to 60°C at 10°C intervals, then from 60°C to 75°C at 5°C intervals, then from 75°C to 90°C at 3°C intervals, then from 90°C to 110°C at 1°C intervals, and finally from 110°C to 120°C at 5°C intervals. Each temperature was maintained for 21 minutes, and then the temperature was raised again. The concentration of the sample (ethylene polymer) eluted at each temperature was detected. An elution temperature-elution amount curve was then measured from the elution amount (mass%) of the sample (ethylene polymer) and the temperature (°C) in the column at that time. The elution amount, integrated elution amount, and the temperature (°C) at which the elution amount in the CFC measurement reached its maximum (Max) were then determined, and the number of peaks in the CFC measurement was calculated. Equipment: Polymer ChAR Automated 3D analyzer CFC-2 Column: Stainless steel microball column (3 / 8" od x 150mm) Eluent: o-dichlorobenzene (for high-performance liquid chromatography) Sample solution concentration: 20 mg of sample (ethylene polymer) / 20 mL of o-dichlorobenzene ·Injection volume: 0.5mL Pump flow rate: 1.0 mL / min Detector: Polymer ChAR infrared spectrophotometer IR4 Detection wave number: 3.42 μm Sample dissolution conditions: 140℃ x 120min dissolution

[0171] (3) Temperature increase separation Temperature-rise liberation fractionation is a method in which a typical Soxhlet extractor is used to dissolve and extract the target components that are soluble in a solvent from a sample. The Soxhlet extractor is a device that has a container containing a heater and solvent at the bottom, a tube in the middle that holds filter paper containing the sample, and a cooling tube at the top. When the container containing the solvent is heated, the solvent evaporates, is cooled by the cooling tube at the top, drips into the sample, dissolves a small amount of solvent-soluble matter, and then returns to the container containing the solvent. Because the solvent-soluble matter has a higher boiling point than the solvent, by repeating this cycle, the solvent-soluble matter (extracted components) gradually becomes concentrated in the container containing the solvent, and the solvent-insoluble matter (residue) remains in the filter paper. Toluene was used as the solvent, and extraction was carried out for 6 hours at a temperature above the boiling point. Thereafter, in order to collect the extract component extracted into the toluene solvent, methanol was added to the toluene solvent to cause reprecipitation, and the extract component was obtained by suction filtration.

[0172] (4) Melting point (Tm) The melting points of the extracted components obtained in (3) above were measured using a differential scanning calorimeter (PerkinElmer DSC-7 model) under the following conditions 1) to 3). 1) Approximately 5 mg of the measurement sample was placed in an aluminum pan, heated to 200°C at 200°C / min, and held at 200°C for 5 minutes. 2) Next, the temperature was lowered from 200°C to 50°C at a rate of 10°C / min, and held for 5 minutes after the temperature drop was complete. 3) Next, the temperature was raised from 50°C to 200°C at a rate of 10°C / min. The highest temperature at the melting peak position of the endothermic curve observed in the process 3) above was taken as the melting point (°C).

[0173] (5) Lamellar thickness of extracted components The lamellar thickness of the extracted component obtained in (3) above was measured by wide-angle X-ray scattering (WAXS) under the following conditions. For the measurement, an Ultima-IV manufactured by Rigaku Corporation was used. Cu-Kα rays were incident on the powder of ethylene polymer, which was the extracted component of the sample, and the diffracted light was detected by D / tex Uitra. The measurement conditions were a distance between the sample and the detector of 285 mm, an excitation voltage of 40 kV, and a current of 40 mA. A focusing optical system was used, and the slit conditions were DS = 1 / 2°, SS = open, and a vertical slit = 10 mm.

[0174] (6) Ti and Al content in the sample The polyethylene resin composition or the extracted component obtained by the above (3) was used as a measurement sample, and the measurement sample was pressure decomposed using a microwave decomposition apparatus (model ETHOS TC, manufactured by Milestone General Co., Ltd.), and the element concentrations of Ti and Al as metals in the sample were measured using an ICP-MS (inductively coupled plasma mass spectrometer, model X Series X7, manufactured by Thermo Fisher Scientific Co., Ltd.) by the internal standard method.

[0175] (7) Comonomer content (α-olefin unit content) The content (mol%) of polymerized units derived from α-olefins in the extracted component obtained in (3) above was measured according to the method disclosed by GJ Ray et al. in Macromolecules, 10, 773 (1977). The content of α-olefin units was 13 The signal intensity of methylene carbon observed in the C-NMR spectrum was used to calculate the value. Measuring device: JEOL ECS-400 Observation kernel: 13 C Observation frequency: 100.53MHz Pulse width: 45° (7.5 μsec) Pulse program: single pulse dec PD: 5 seconds Measurement temperature: 130℃ Accumulation count: 30,000 times or more Reference: PE (-eee-) signal is 29.9 ppm Solvent: o-dichlorobenzene-d4 Sample concentration: 5 to 10% by mass Melting temperature: 130~140℃

[0176] (8) Method for producing polyethylene resin composition When the total amount of the ethylene polymer and liquid paraffin produced in the Examples and Comparative Examples described below is taken as 100 parts by mass, 30 to 40 parts by mass of the ethylene polymer, 60 to 70 parts by mass of liquid paraffin (liquid paraffin (product name: Sumoil P-350P) manufactured by Matsumura Oil Research Institute Co., Ltd.), and 1 part by mass of an antioxidant (tetrakis[methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)]methane (product name: ANOX20) manufactured by Great Lakes Chemical Japan Co., Ltd.) were blended to prepare a slurry liquid. The resulting slurry liquid was purged with nitrogen and then fed via a feeder under a nitrogen atmosphere into a twin-screw extruder (main body model: 2D25S) for a Labo Plastomill (main body model: 30C150) manufactured by Toyo Seiki Co., Ltd., where it was kneaded at 200°C and extruded through a T-die attached to the tip of the extruder. It was then immediately cooled and solidified on a cast roll cooled to 25°C to form a gel-like sheet. This gel-like sheet was stretched 7x7 times at 120°C using a simultaneous biaxial stretching machine, and the stretched film was then immersed in methyl ethyl ketone or hexane to extract and remove the liquid paraffin, followed by vacuum drying for 24 hours or more. Further, the film was heat-set at 125°C for 3 minutes to obtain a polyethylene resin composition in the form of a microporous film.

[0177] (9) Fuse performance The fuse performance of the microporous polyethylene resin composition membrane produced by the method described in (8) above was evaluated by impregnating the polyethylene resin composition with an electrolyte solution, sandwiching the composition between SUS plate electrodes to prepare a cell, and measuring the AC resistance of the cell while raising the temperature. The temperature at which the resistance value suddenly increased was taken as the fuse temperature (°C), and evaluation was performed with n = 5 measurements, and the average was calculated. The evaluation criteria were as follows: (Evaluation criteria) ◎ (Good): Less than 132℃ ○ (Normal): 132℃ or higher and less than 135℃ × (bad): 135℃ or higher

[0178] (10) Fuse speed The fuse speed of the polyethylene resin composition in the form of a microporous membrane produced by the method described in (8) above was evaluated by impregnating the polyethylene resin composition with an electrolyte solution, sandwiching the polyethylene resin composition between SUS plate electrodes to prepare a cell, and measuring the AC resistance of the cell while raising the temperature. A sudden increase in resistance was confirmed near the melting point of the polyethylene resin composition (fuse performance), and the fuse speed was evaluated as the time (seconds) from the start of the resistance increase until the maximum resistance value was reached. Five measurements (n = 5) were performed, and the average value was calculated as the fuse speed. The evaluation criteria were as follows: (Evaluation criteria) ◎ (Good): Less than 5 seconds ○ (Normal): 5 seconds or more but less than 10 seconds × (bad): 10 seconds or more

[0179] (11)Piercing strength A puncture test was carried out on the microporous polyethylene resin composition membrane produced by the method described in (8) above using a Kato Tech "KES-G5 Handy Compression Tester" (trademark) under conditions of a needle tip curvature radius of 0.5 mm and a puncture speed of 2 mm / sec, and the maximum puncture load (N) was measured. A maximum puncture load (N) of 3.5 N or more indicates sufficiently excellent strength. Evaluation was performed with n = 10 measurements, and the average value was calculated as the puncture strength. The evaluation criteria are as follows: (Evaluation criteria) ◎ (Good): 3.5N or more ○ (Normal): 3.0N or more and less than 3.5N × (bad): Less than 3.0N

[0180] (12) Number of film defects The number of defects (excluding impurities such as dust that are observed as black spots when the film is observed under transmitted light) present within a 250 mm × 250 mm area of a microporous polyethylene resin composition film formed by the method described in (8) above was visually counted. Based on the obtained number, the defects were evaluated according to the following evaluation criteria. Evaluation was performed with n = 10 measurements, and the average value was calculated as the number of film defects. The evaluation criteria are as follows: (Evaluation criteria) ◎ (Good): 10 or less ○ (normal): 11 to 20 pieces × (bad): 21 or more

[0181] (13) Unevenness in film thickness The film thickness of the microporous polyethylene resin composition film formed by the method described in (8) above was measured at room temperature using a micro thickness gauge (Type KBM (registered trademark) manufactured by Toyo Seiki Seisaku-sho. Measurements were taken at 10 randomly selected locations evenly over every 1 m of the film, and a total of 50 locations over a 5 m film were measured, and the average film thickness was calculated. The average film thickness was 5 μm or more and 30 μm or less. (Evaluation criteria) ◎ (Good): Variation of less than ±3 μm from the average film thickness 〇 (Normal): Variation of the average film thickness between ±3μm and ±5μm × (bad): Variation of ±5 μm or more from the average film thickness

[0182] [Catalyst synthesis method] (Production Example 1: Catalyst Synthesis Example 1: Preparation of Solid Catalyst Component [A]) (1) Synthesis of raw material (a-1) In an 8L stainless steel autoclave that has been thoroughly purged with nitrogen, add 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, and 146 mL of 5.47 mol / L n-butanol hexane solution was added dropwise over 3 hours while stirring at 50°C. After completion of the reaction, the line was washed with 300 mL of hexane. Stirring was continued for another 2 hours at 50°C. After the reaction was completed, the mixture was cooled to room temperature and used as raw material (a-1). The magnesium concentration of raw material (a-1) was 0.704 mol / L. (2) Synthesis of raw material (a-2) In an 8L stainless steel autoclave that has been thoroughly purged with nitrogen, add 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 stirred at 80°C, while 240 mL of hexane solution of 8.33 mol / L methylhydrogenpolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) was pressure-fed, and stirring was continued for another 2 hours at 80°C. After the reaction was completed, the mixture was cooled to room temperature and used as raw material (a-2). The total concentration of magnesium and aluminum in raw material (a-2) was 0.786 mol / L. (3) (A-1) Synthesis of the carrier An 8L stainless steel autoclave was charged with 1,000mL of a 1mol / L hydroxytrichlorosilane hexane solution, and 1,340mL of the hexane solution of the organomagnesium compound (a-1) (equivalent to 943mmol of magnesium) was added dropwise over 3 hours at 65°C. The reaction was continued for another 1 hour with stirring at 65°C. After the reaction was completed, the supernatant was removed and the mixture was washed four times with 1,800mL of hexane to obtain the (A-1) carrier. Analysis of this carrier revealed that it contained 7.5mmol of magnesium per gram of solid. (4) Preparation of solid catalyst component [A] To 1,970 mL of hexane slurry containing 110 g of the above (A-1) carrier, 103 mL of a 1 mol / L hexane solution of titanium tetrachloride and 131 mL of raw material (a-2) were added simultaneously over 3 hours while stirring at 10°C. After the addition, the reaction was continued for 1 hour at 10°C. After the reaction was completed, the supernatant was removed, and the unreacted raw material components were removed by washing four times with hexane to prepare solid catalyst component [A].

[0183] (Production Example 2: Catalyst Synthesis Example 2: Preparation of Supported Metallocene Catalyst Component [B]) (1) Synthesis of raw material [b-1] Average particle size is 7 μm and surface area is 700 m 2 Spherical silica with a particle size of 1.9 mL / g and an intraparticle pore volume of 1.9 mL / g was calcined at 500°C for 5 hours in a nitrogen atmosphere and dehydrated. In a nitrogen atmosphere, 40 g of this dehydrated silica was dispersed in 800 mL of hexane in a 1.8 L capacity autoclave to obtain a slurry. While the obtained slurry was kept at 20° C. under stirring, 100 mL of a hexane solution of triethylaluminum (concentration: 1 mol / L) was added dropwise over 1 hour, and then the mixture was stirred at the same temperature for 2 hours. The resulting reaction mixture was then decanted to remove unreacted triethylaluminum from the supernatant, yielding 800 mL of a hexane slurry of raw material [b-1], a silica component treated with triethylaluminum. (2) Preparation of raw material [b-2] 200 mmol of [(Nt-butylamido)(tetramethyl-η5-cyclopentadienyl)dimethylsilane]titanium-1,3-pentadiene (hereinafter referred to as "titanium complex") was dissolved in 1250 mL of Isopar E [a trade name for a hydrocarbon mixture manufactured by Exxon Chemical Company (USA)], 40 mL of a 1 mol / L hexane solution of commercially available butylethylmagnesium was added, and further hexane was added to adjust the titanium complex concentration to 0.1 mol / L, thereby obtaining raw material [b-2]. (3) Preparation of raw material [b-3] 5.7 g of bis(hydrogenated tallow alkyl)methylammonium-tris(pentafluorophenyl)(4-hydroxyphenyl)borate (hereinafter referred to as "borate") was added and dissolved in 50 mL of toluene to obtain a 100 mmol / L toluene solution of borate. 5 mL of a 1 mol / L hexane solution of ethoxydiethylaluminum was added to this toluene solution at room temperature, and further hexane was added to adjust the borate concentration in the solution to 70 mmol / L. The mixture was then stirred at room temperature for 1 hour to obtain the raw material [b-3], a reaction mixture containing borate. (4) Preparation of supported metallocene catalyst [B] While stirring 800 mL of the slurry of raw material [b-1] (the silica component obtained in (1) above) at 20°C, 32 mL of raw material [b-2] (the titanium complex obtained in (2) above) and 46 mL of raw material [b-3] (the reaction mixture containing the borate obtained in (3) above) were simultaneously added over one hour, and the mixture was stirred at the same temperature for another hour to react the titanium complex with the borate. After the reaction was completed, the supernatant was removed, and unreacted catalyst raw material was removed with hexane to obtain a supported metallocene catalyst [B] (hereinafter also referred to as solid catalyst component [B]) in which catalytically active species were formed on the silica.

[0184] Example 1 (Polymerization step of ethylene polymer (A-1)) Hexane, ethylene, 1-butene, hydrogen, and catalyst were continuously fed into a 300 L vessel-type polymerization reactor equipped with a stirrer. The polymerization pressure was 0.5 MPa. The polymerization temperature was maintained at 78°C by jacket cooling. Hexane was prepared by pre-pressurizing ethylene gas at 0.2 MPa to prepare hexane containing dissolved ethylene. The hexane was adjusted to 3°C and fed into the bottom of the polymerization reactor at a rate of 40 L / hr. The remaining ethylene was fed from the bottom of the polymerization vessel so as to maintain the polymerization pressure at 0.5 MPa. 1-Butene was introduced from the gas phase at a ratio of 5 mol% to ethylene. Solid catalyst component [A] and a cocatalyst mixture of triisobutylaluminum and diisobutylaluminum hydride (9:1 mixture) were used. Solid catalyst component [A] was fed from the bottom of the polymerization reactor at a linear feed rate of 2.0 m / s and a rate of 0.2 g / hr, while the temperature was maintained at 3°C. Triisobutylaluminum was fed from the bottom of the polymerization reactor at a rate of 10 mmol / hr. The catalyst, ethylene and hexane were all fed simultaneously. The production rate of the ethylene polymer was 10 kg / hr. Hydrogen was continuously supplied by a pump so that the hydrogen concentration relative to ethylene in the gas phase was 35 mol%. Hydrogen was supplied through the catalyst introduction line so that it would come into contact with the catalyst beforehand. The catalytic activity was 80,000 g-PE / g-solid catalyst component [A]. The polymer slurry was continuously discharged into a flash drum at a pressure of 0.05 MPa and a temperature of 70°C so that the level in the polymerization reactor was kept constant, and unreacted ethylene and hydrogen were separated.

[0185] Next, the polymer slurry was continuously sent to a centrifuge so as to keep the level of the polymerization reactor constant, and the ethylene polymer was separated from the other components such as the solvent, etc. The content of the solvent, etc. relative to the polymer at this time was 45% by mass.

[0186] The separated ethylene polymer was dried at 85°C while blowing nitrogen. In this drying step, steam was sprayed onto the ethylene polymer powder to deactivate the catalyst and co-catalyst. The obtained ethylene polymer powder was sieved using a sieve with a mesh size of 425µm to remove any particles that did not pass through the sieve, thereby obtaining an ethylene polymer (A-1). The density was 947kg / m 3 The MFR was 5g / 10min.

[0187] (Polymerization step of ethylene polymer (B-1)) Hexane, ethylene, hydrogen, and catalyst were continuously fed into a 300-L vessel-type polymerization reactor equipped with a stirrer. The polymerization pressure was 0.5 MPa. The polymerization temperature was maintained at 85°C by jacket cooling. Hexane was fed into the bottom of the reactor at 40 L / hr. Solid catalyst component [A] and triisobutylaluminum as a cocatalyst were used. Solid catalyst component [A] was added at a rate of 0.2 g / hr from the center of the reactor between the liquid level and the bottom, and triisobutylaluminum was added at a rate of 10 mmol / hr from the center of the reactor between the liquid level and the bottom. Solid catalyst component [A] and the cocatalyst triisobutylaluminum and diisobutylaluminum hydride (9:1 mixture) were alternately added intermittently so that they came into contact immediately after being added to the reactor. The ethylene polymer production rate was 10 kg / hr. Hydrogen was continuously fed by a pump to maintain a hydrogen concentration of 5.5 mol% relative to ethylene in the gas phase. Hydrogen was supplied through the catalyst introduction line to allow it to come into contact with the catalyst beforehand, and ethylene was supplied from the bottom of the polymerization reactor. The catalytic activity was 80,000 g PE / g solid catalyst component [A]. The polymer slurry was continuously discharged into a flash drum at a pressure of 0.05 MPa and a temperature of 70°C to maintain a constant level in the polymerization reactor, and unreacted ethylene and hydrogen were separated.

[0188] Next, the polymer slurry was continuously sent to a centrifuge so as to keep the level of the polymerization reactor constant, and the ethylene polymer was separated from the other components such as the solvent, etc. The content of the solvent, etc. relative to the ethylene polymer at this time was 45% by mass.

[0189] The separated ethylene polymer was dried at 85°C while blowing nitrogen. In this drying step, steam was sprayed onto the ethylene polymer powder to deactivate the catalyst and co-catalyst. 500 ppm of calcium stearate (C60, manufactured by Dainichi Chemical Co., Ltd.) was added to the obtained ethylene polymer powder, and the mixture was uniformly mixed using a Henschel mixer. The obtained ethylene polymer powder was sieved using a sieve with a mesh size of 425 μm to remove any particles that did not pass through the sieve, thereby obtaining an ethylene polymer (B-1). The weight-average molecular weight was 70 × 10 4It was.

[0190] (Method of producing polyethylene resin composition) To a total of 100 parts by mass of the ethylene polymer (A-1) and the ethylene polymer (B-1) (75 parts by mass of (A-1) and 25 parts by mass of (B-1)), 0.3 parts by mass of pentaerythrityl tetrakis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] as an antioxidant was added, and the mixture was dry-blended using a tumbler blender to obtain a polyethylene powder mixture. The resulting polyethylene powder mixture was purged with nitrogen and then fed into a twin-screw extruder through a feeder under a nitrogen atmosphere. Furthermore, 65 parts by mass of liquid paraffin (P-350 (trademark) manufactured by Matsumura Oil Co., Ltd.) was injected into the extruder via a side feed, kneaded at 200°C, extruded from a T-die installed at the tip of the extruder, and immediately cooled and solidified on a cast roll cooled to 25°C to form a gel-like sheet with a thickness of 1500 μm. This gel-like sheet was stretched 7x7 times at 120°C using a simultaneous biaxial stretching machine, and the stretched film was then immersed in methylene chloride to extract and remove the liquid paraffin, followed by drying. The film was then re-stretched to 1.2×1.2 times its original size and then heat-treated to obtain a microporous membrane of a polyethylene resin composition. The measurement and evaluation results are shown in Table 1.

[0191] Example 2 (Polymerization step of ethylene polymer (A-2)) An ethylene-based polymer (A-2) was obtained in the same manner as in Example 1 for the ethylene-based polymer (A-1), except that in the polymerization step, the hydrogen concentration was 45 mol % and 1-butene was introduced from the gas phase in an amount of 6 mol % relative to ethylene. The density was 947 kg / m 3 The MFR was 10 g / 10 min. The microporous polyethylene resin composition membrane of Example 2 was obtained in the same manner as in Example 1, except that the ethylene polymer (A-2) and the ethylene polymer (B-1) were used (75 parts by mass of (A-2) and 25 parts by mass of (B-1)). The measurement and evaluation results are shown in Table 1.

[0192] Example 3 (Polymerization step of ethylene polymer (A-3)) An ethylene-based polymer (A-3) was obtained in the same manner as in Example 1 for the ethylene-based polymer (A-1), except that in the polymerization step, the hydrogen concentration was 50 mol%, 1-butene was introduced from the gas phase at 7.5 mol% relative to ethylene, the temperature of hexane in which ethylene was dissolved was adjusted to 4°C and fed from the side of the polymerization vessel, and the catalyst temperature was adjusted to 4°C and fed from the middle between the liquid surface and the bottom of the polymerization vessel. 3 The MFR was 30g / 10min. The microporous polyethylene resin composition membrane of Example 3 was obtained in the same manner as in Example 1, except that the ethylene polymer (A-3) and the ethylene polymer (B-1) were used (75 parts by mass of (A-3) and 25 parts by mass of (B-1)). The measurement and evaluation results are shown in Table 1.

[0193] Example 4 (Polymerization step of ethylene polymer (A-4)) In the polymerization process, a supported metallocene catalyst component [B] was used, and 1 mol / L of Mg6(C4H9) was added as a cocatalyst to an 8 L stainless steel autoclave that was fully purged with nitrogen. 12 2,000 mL of a 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 a hexane solution of 8.33 mol / L methylhydrogenpolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) was pumped in. Stirring was continued at 80°C for another 2 hours, and the mixture was cooled to room temperature. An ethylene-based polymer (A-4) was obtained in the same manner as for the ethylene-based polymer (A-1) in Example 1, except that the hydrogen concentration was 30 mol% and 1-butene was introduced from the gas phase at 8 mol% relative to ethylene. The density was 941 kg / m 3The MFR was 2.5 g / 10 min. The microporous polyethylene resin composition membrane of Example 4 was obtained in the same manner as in Example 1, except that the ethylene polymer (A-4) and the ethylene polymer (B-1) were used (75 parts by mass of (A-4) and 25 parts by mass of (B-1)). The measurement and evaluation results are shown in Table 1.

[0194] Example 5 (Polymerization step of ethylene polymer (A-5)) In the polymerization process, a supported metallocene catalyst component [B] was used, and 1 mol / L of Mg6(C4H9) was added as a cocatalyst to an 8 L stainless steel autoclave that was fully purged with nitrogen. 12 2,000 mL of a 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 a hexane solution of 8.33 mol / L methylhydrogenpolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) was pumped in. Stirring was continued at 80°C for another 2 hours, and the mixture was cooled to room temperature. An ethylene-based polymer (A-5) was obtained in the same manner as for the ethylene-based polymer (A-1) in Example 1, except that the hydrogen concentration was 35 mol% and 1-butene was introduced from the gas phase at 9 mol% relative to ethylene. The density was 941 kg / m 3 The MFR was 5 g / 10 min. The microporous polyethylene resin composition membrane of Example 5 was obtained in the same manner as in Example 1, except that the ethylene polymer (A-5) and the ethylene polymer (B-1) were used (75 parts by mass of (A-5) and 25 parts by mass of (B-1)). The measurement and evaluation results are shown in Table 1.

[0195] Example 6 (Polymerization step of ethylene polymer (A-6)) An ethylene-based polymer (A-6) was obtained in the same manner as in Example 1 for the ethylene-based polymer (A-1), except that in the polymerization step, the hydrogen concentration was 40 mol%, 1-butene was introduced from the gas phase in an amount of 11 mol% relative to ethylene, the temperature of the hexane containing dissolved ethylene was adjusted to 4°C, and the catalyst temperature was adjusted to 25°C. The density was 941 kg / m 3The MFR was 10 g / 10 min. The microporous polyethylene resin composition membrane of Example 6 was obtained in the same manner as in Example 1, except that the ethylene polymer (A-6) and the ethylene polymer (B-1) were used (75 parts by mass of (A-6) and 25 parts by mass of (B-1)). The measurement and evaluation results are shown in Table 1.

[0196] Example 7 (Polymerization step of ethylene polymer (A-7)) In the polymerization step, ethylene-dissolved hexane was adjusted to 25°C and fed from the side of the polymerization vessel, the catalyst was maintained at 25°C and fed from the middle between the liquid level and the bottom of the polymerization vessel at a feed linear velocity of 3.5 m / s, the co-catalyst was fed from the middle between the liquid level and the bottom of the polymerization vessel, the catalyst and ethylene-dissolved hexane were fed separately to three locations from the bottom of each polymerization vessel, and the catalyst, ethylene, and hexane were not fed simultaneously. An ethylene-based polymer (A-7) was obtained by the same procedure as for the ethylene-based polymer (A-1) in Example 1. The density was 947 kg / m 3 The MFR was 5g / 10min. (Polymerization step of ethylene polymer (B-2)) In the polymerization process, a supported metallocene catalyst component [B] was used, and 1 mol / L of Mg6(C4H9) was added as a cocatalyst to an 8 L stainless steel autoclave that was fully purged with nitrogen. 12 Ethylene-based polymer (B-2) was obtained in the same manner as for ethylene-based polymer (B-1) in Example 1, except that 2,000 mL of a hexane solution of AL(C2H5)3 (equivalent to 2,000 mmol of magnesium and aluminum) was charged and stirred at 80°C, while 240 mL of a hexane solution of 8.33 mol / L methylhydrogenpolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) was pumped in, and the mixture was further stirred at 80°C for 2 hours and then cooled to room temperature. 4 It was. The microporous polyethylene resin composition membrane of Example 7 was obtained in the same manner as in Example 1, except that the ethylene polymer (A-7) and the ethylene polymer (B-2) were used (75 parts by mass of (A-7) and 25 parts by mass of (B-2)). The measurement and evaluation results are shown in Table 1.

[0197] [ Reference example 8) (Polymerization step of ethylene polymer (A-8)) In the polymerization process, the hydrogen concentration was set to 30 mol%, and 1-butene was used in an amount of 8 m % gas phase, and ethylene-dissolved hexane was adjusted to 25°C and fed from the side of the polymerization vessel. The catalyst is fed from the middle of the liquid surface and the bottom of the polymerization vessel, and the co-catalyst is fed from the middle of the liquid surface and the bottom of the polymerization vessel. The catalyst and ethylene-dissolved hexane were fed from the bottom of each polymerization reactor to three separate locations. The catalyst / ethylene / hexane feeds were not simultaneous. Ethylene polymer (A-8) was obtained by the same procedure as in the case of the ethylene polymer (A-1). The density is 941 kg / m 3 The MFR was 2.5g / 10min. Also, Reference example The microporous polyethylene resin composition of No. 8 is an ethylene polymer (A-8 ) and ethylene polymer (B-2) (75 parts by mass of (A-8) and 25 parts by mass of (B-2) The results of the measurements and evaluations are shown in Table 1.

[0198] Example 9 (Polymerization step of ethylene polymer (B-3)) An ethylene-based polymer (B-3) was obtained in the same manner as in Example 1 for the ethylene-based polymer (B-1), except that the polymerization temperature in the polymerization step was adjusted to 78° C. The weight-average molecular weight was 100×10 4 It was. The microporous polyethylene resin composition membrane of Example 9 was obtained in the same manner as in Example 1, except that the ethylene polymer (A-2) and the ethylene polymer (B-3) were used in an amount of 65 parts by mass of the ethylene polymer (A-2) and 35 parts by mass of the ethylene polymer (B-3), totaling 100 parts by mass. The measurement and evaluation results are shown in Table 1.

[0199] Example 10 (Polymerization step of ethylene polymer (B-4)) An ethylene-based polymer (B-4) was obtained in the same manner as in Example 1 for the ethylene-based polymer (B-1), except that the polymerization temperature in the polymerization step was adjusted to 75° C. The weight-average molecular weight was 200×10 4 It was. The microporous polyethylene resin composition of Example 10 was obtained in the same manner as in Example 1, except that the ethylene polymer (A-2) and the ethylene polymer (B-4) were used in an amount of 65 parts by mass of the ethylene polymer (A-2) and 35 parts by mass of the ethylene polymer (B-4), totaling 100 parts by mass. The measurements and results are shown in Table 1.

[0200] Example 11 As shown below, an ethylene polymer (A-14) was polymerized in a first-stage reactor, and an ethylene polymer (B-8) was polymerized in a second-stage reactor to obtain an ethylene polymer of Example 11. The ethylene polymer of Example 11 had a weight-average molecular weight of 350,000 and a molecular weight distribution of 18. The measurements and results are shown in Table 1.

[0201] (Polymerization step of ethylene polymer (A-14)) Ethylene-based polymers were polymerized using a 300-L vessel-type polymerization reactor equipped with three sweepback impellers and three baffles. The solvent, hexane, was pre-pressurized with 0.2 MPa ethylene gas to prepare ethylene-dissolved hexane and adjusted to 3°C. The hexane was fed from the bottom of the polymerization reactor at a flow rate of 40 L / hr, with the stirring speed set to 230 rpm. The remaining ethylene was fed from the bottom of the polymerization reactor to maintain the polymerization pressure at 0.5 MPa. The polymerization catalyst used was solid catalyst component [A], and a cocatalyst mixture of triisobutylaluminum and diisobutylaluminum hydride (9:1 mixture). Solid catalyst component [A] was fed from the bottom of the polymerization reactor at a linear feed rate of 2.0 m / s and a rate of 0.2 g / hr, while maintaining the temperature at 3°C. Triisobutylaluminum was fed from the bottom of the polymerization reactor at a rate of 10 mmol / hr. The catalyst, ethylene and hexane were all fed simultaneously. Hydrogen was supplied at 44 mol% (molar ratio: hydrogen / (ethylene + hydrogen + 1-butene)). The polymerization temperature was 78°C, the polymerization pressure was 0.65 MPa, the average residence time was 3 hours, and 1-butene was supplied as a comonomer at 5.7 mol% (molar ratio: 1-butene / (ethylene + hydrogen + 1-butene)). The weight average molecular weight of the ethylene polymer (A-14) thus obtained was 60,000. The polymerization activity in the first-stage reactor was 60,000 g per 1 g of catalyst. The polymer slurry in the polymerization reactor was introduced into an intermediate flash tank at a pressure of 0.2 MPa and a temperature of 80°C so that the level in the polymerization reactor was kept constant, and unreacted ethylene and hydrogen were separated.

[0202] (Polymerization step of ethylene polymer (B-8)) The polymer slurry containing the ethylene polymer (A-14) was transferred from the intermediate flash tank to a 300-L vessel-type polymerization reactor equipped with three sweepback impellers and three baffles, where it was subsequently polymerized to produce an ethylene polymer (B-8). The stirring speed was 200 rpm, and a cocatalyst mixture of triisobutylaluminum and diisobutylaluminum hydride (9:1 mixture) was fed into the bottom of the polymerization reactor at a rate of 10 mmol / hr. Hydrogen was fed at 3 mol% (molar ratio: hydrogen / (ethylene + hydrogen + 1-butene)), and 1-butene was fed as a comonomer at 1.1 mol% (molar ratio: 1-butene / (ethylene + hydrogen + 1-butene)). The polymerization temperature was 78°C, the polymerization pressure was 0.30 MPa to achieve a production rate of 7.0 kg / hr, and the average residence time was 0.85 h. The weight average molecular weight of the thus obtained ethylene polymer (B-8) was 350,000. The polymerization activity in the second-stage reactor was 8,800 g per 1 g of catalyst. The polymer slurry in the polymerization reactor was introduced into a final flash tank at a pressure of 0.05 MPa and a temperature of 80°C to maintain a constant level in the polymerization reactor, where unreacted ethylene and hydrogen were separated. The average residence time in the final flash tank was 1 hour. Next, the polymer slurry was continuously sent from the flash tank to a centrifuge by a pump to separate the ethylene polymer and the solvent, and the separated ethylene polymer was then sent to a rotary kiln-type dryer controlled at 85°C and dried while blowing nitrogen, to obtain an ethylene polymer powder. In this drying step, steam was sprayed onto the ethylene polymer to deactivate the catalyst and co-catalyst.

[0203] (Method of producing polyethylene resin composition) To 100 parts by mass of the ethylene polymer powder, 0.3 parts by mass of pentaerythrityl tetrakis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] was added as an antioxidant, and the mixture was dry-blended using a tumbler blender to obtain an ethylene polymer powder mixture. The resulting ethylene polymer powder mixture was purged with nitrogen and then fed into a twin-screw extruder through a feeder under a nitrogen atmosphere. Furthermore, 65 parts by mass of liquid paraffin (P-350 (trademark) manufactured by Matsumura Oil Co., Ltd.) was injected into the extruder via a side feed, kneaded at 200°C, extruded from a T-die installed at the tip of the extruder, and immediately cooled and solidified on a cast roll cooled to 25°C to form a gel-like sheet with a thickness of 1500 μm. This gel-like sheet was stretched 7x7 times at 120°C using a simultaneous biaxial stretching machine to form a stretched film, which was then immersed in methylene chloride to extract and remove the liquid paraffin, and then dried. Next, the film is stretched again to 1.2 × 1.2 times, and then heat-treated to obtain a microporous polyethylene resin composition. The measurement and evaluation results are shown in Table 1.

[0204] Comparative Example 1 (Polymerization step of ethylene polymer (A-9)) Hexane, ethylene, 1-butene, hydrogen, and catalyst were continuously fed into a 300-L vessel-type polymerization reactor equipped with a stirrer. The polymerization pressure was 0.5 MPa. The polymerization temperature was maintained at 78°C by jacket cooling. Hexane was prepared as ethylene-dissolved hexane, pre-pressurized with ethylene gas at 0.2 MPa, and fed into the side of the reactor at 40 L / hr. 1-Butene was also introduced from the gas phase at 6 mol% relative to the ethylene. Solid catalyst component [A] and a 9:1 mixture of triisobutylaluminum and diisobutylaluminum hydride were used as cocatalysts. Solid catalyst component [A] was maintained at 25°C and added at a linear feed rate of 3.0 m / s at a rate of 0.2 g / hr from the center between the liquid level and the bottom of the polymerization reactor. Triisobutylaluminum was added at a rate of 10 mmol / hr from the center between the liquid level and the bottom of the polymerization reactor. The ethylene polymer production rate was 10 kg / hr. Hydrogen was continuously supplied by a pump so that the hydrogen concentration relative to ethylene in the gas phase was 45 mol%. Hydrogen was supplied through the catalyst introduction line to allow it to come into contact with the catalyst beforehand, and ethylene was supplied from the side of the polymerization reactor. The catalytic activity was 80,000 g-PE / g-solid catalyst component [A]. The polymer slurry was continuously discharged into a flash drum at a pressure of 0.05 MPa and a temperature of 70°C so that the level in the polymerization reactor was kept constant, and unreacted ethylene and hydrogen were separated.

[0205] Next, the polymer slurry was continuously sent to a centrifuge so as to keep the level of the polymerization reactor constant, and the ethylene polymer was separated from the other components such as the solvent, etc. The content of the solvent, etc. relative to the polymer at this time was 45% by mass.

[0206] The separated ethylene polymer was dried at 85°C while blowing nitrogen. In this drying step, steam was sprayed onto the ethylene polymer powder to deactivate the catalyst and co-catalyst. The obtained ethylene polymer powder was sieved through a sieve with a mesh size of 425 μm to remove any particles that did not pass through the sieve, thereby obtaining an ethylene polymer (A-9). The density was 947 kg / m 3 The MFR was 10g / 10min.

[0207] (Polymerization step of ethylene polymer (B-5)) Hexane, ethylene, hydrogen, and catalyst were continuously fed into a 300-L vessel-type polymerization reactor equipped with a stirrer. The polymerization pressure was 0.5 MPa. The polymerization temperature was maintained at 85°C by jacket cooling. Hexane was maintained at 25°C and fed into the side of the reactor at 40 L / hr. Solid catalyst component [A] and a 9:1 mixture of triisobutylaluminum and diisobutylaluminum hydride as cocatalysts were used. Solid catalyst component [A] was added at a rate of 0.2 g / hr from the center of the reactor, halfway between the liquid level and the bottom. Triisobutylaluminum was added at a rate of 10 mmol / hr from the center of the reactor, halfway between the liquid level and the bottom. Solid catalyst component [A] and the cocatalyst triisobutylaluminum were added simultaneously through a single feed line, so that they came into contact before entering the reactor. The ethylene polymer production rate was 10 kg / hr. Hydrogen was continuously supplied by a pump so that the hydrogen concentration relative to ethylene in the gas phase was 5.5 mol%. Hydrogen was supplied through the catalyst introduction line to allow it to come into contact with the catalyst beforehand, and ethylene was supplied from the side of the polymerization reactor. The catalytic activity was 80,000 g-PE / g-solid catalyst component [A]. The polymer slurry was continuously discharged into a flash drum at a pressure of 0.05 MPa and a temperature of 70°C to maintain a constant level in the polymerization reactor, and unreacted ethylene and hydrogen were separated.

[0208] Next, the polymer slurry was continuously sent to a centrifuge so as to keep the level of the polymerization reactor constant, and the ethylene polymer was separated from the other components such as the solvent, etc. The content of the solvent, etc. relative to the ethylene polymer at this time was 45% by mass.

[0209] The separated ethylene polymer was dried at 85°C while blowing nitrogen. In this drying step, steam was sprayed onto the ethylene polymer powder to deactivate the catalyst and co-catalyst. 500 ppm of calcium stearate (C60, manufactured by Dainichi Chemical Co., Ltd.) was added to the obtained ethylene polymer powder, and the mixture was uniformly mixed using a Henschel mixer. The obtained ethylene polymer powder was sieved using a sieve with 425 μm openings to remove any particles that did not pass through the sieve, thereby obtaining an ethylene polymer (B-5). The weight-average molecular weight was 200 × 10 4 It was.

[0210] (Method of producing polyethylene resin composition) To a total of 100 parts by mass of the ethylene polymer (A-9) and the ethylene polymer (B-5) (75 parts by mass of (A-9) and 25 parts by mass of (B-5)), 0.3 parts by mass of pentaerythrityl tetrakis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] was added as an antioxidant, and the mixture was dry-blended using a tumbler blender to obtain an ethylene polymer powder mixture. The resulting ethylene polymer powder mixture was purged with nitrogen and then fed into a twin-screw extruder via a feeder under a nitrogen atmosphere. 65 parts of liquid paraffin (P-350™, manufactured by Matsumura Oil Co., Ltd.) was then added via a side feed, mixed at 200°C, extruded through a T-die attached to the tip of the extruder, and immediately cooled and solidified on a cast roll cooled to 25°C to form a gel-like sheet with a thickness of 1500 μm. This gel-like sheet was stretched 7x7 times at 120°C using a simultaneous biaxial stretching machine to form a stretched film, which was then immersed in methylene chloride to extract and remove the liquid paraffin, and then dried. The film was then re-stretched to 1.2 × 1.2 times its original size and then heat-treated to obtain a microporous membrane of a polyethylene resin composition. The measurement and evaluation results are shown in Table 2.

[0211] Comparative Example 2 (Polymerization step of ethylene polymer (A-10)) An ethylene-based polymer (A-10) was obtained in the same manner as in the production of the ethylene-based polymer (A-9) in Comparative Example 1, except that in the polymerization step, ethylene was not dissolved in hexane, the hydrogen concentration relative to the gaseous ethylene was adjusted to 46 mol%, 1-butene was introduced from the gaseous phase at 15 mol% relative to the ethylene, and the catalyst feed linear velocity was set to 6.0 m / s. The density was 920 kg / m 3 The MFR was 20g / 10min. For the microporous membrane of Comparative Example 2, the ethylene polymer (A-10) and the ethylene polymer (B-5) were used, and a microporous polyethylene resin composition was obtained in the same manner as in Comparative Example 1, except that 75 parts by mass of the ethylene polymer (A-10) and 25 parts by mass of the ethylene polymer (B-5) were used to make a total of 100 parts by mass. The measurement and evaluation results are shown in Table 2.

[0212] Comparative Example 3 (Polymerization step of ethylene polymer (A-11)) An ethylene-based polymer (A-11) was obtained in the same manner as in the production of the ethylene-based polymer (A-9) in Comparative Example 1, except that in the polymerization step, ethylene was not dissolved in hexane, the hydrogen concentration relative to the gaseous ethylene was adjusted to 46 mol%, 1-butene was introduced from the gaseous phase at 15 mol% relative to the ethylene, the catalyst temperature was set at 3°C, and the feed linear velocity was set at 2.0 m / s. The density was 920 kg / m 3 The MFR was 20g / 10min. (Polymerization step of ethylene polymer (B-6)) An ethylene-based polymer (B-6) was obtained in the same manner as in the production of the ethylene-based polymer (B-5) in Comparative Example 1, except that in the polymerization step, the polymerization temperature was adjusted to 90°C and 1-butene was introduced from the gas phase in an amount of 0.1 mol% relative to ethylene. The weight-average molecular weight was 20 × 10 4 For the microporous membrane of Comparative Example 3, an ethylene polymer (A-11) and an ethylene polymer (B-6) were used, and a microporous polyethylene resin composition was obtained in the same manner as in Comparative Example 1, except that the ethylene polymer (A-11) was 75 parts by mass and the ethylene polymer (B-6) was 25 parts by mass, totaling 100 parts by mass. The measurement and evaluation results are shown in Table 2.

[0213] Comparative Example 4 (Polymerization step of ethylene polymer (A-12)) An ethylene-based polymer (A-12) was obtained in the same manner as in the ethylene-based polymer (A-9) in Comparative Example 1, except that in the polymerization step, ethylene was not dissolved in hexane, the catalyst temperature was set to 3°C, the feed linear velocity was set to 2.0 m / s, and the catalyst, ethylene, and hexane were all fed simultaneously. The density was 947 kg / m 3 The MFR was 10g / 10min. (Polymerization step of ethylene polymer (B-7)) An ethylene-based polymer (B-7) was obtained in the same manner as in the production of the ethylene-based polymer (B-5) in Comparative Example 1, except that the polymerization temperature in the polymerization step was adjusted to 70° C. The weight-average molecular weight was 400×10 4 For the microporous membrane of Comparative Example 4, an ethylene polymer (A-12) and an ethylene polymer (B-7) were used, and a microporous polyethylene resin composition was obtained in the same manner as in Comparative Example 1, except that 75 parts by mass of the ethylene polymer (A-12) and 25 parts by mass of the ethylene polymer (B-7) were used, totaling 100 parts by mass. The measurement and evaluation results are shown in Table 2.

[0214] Comparative Example 5 (Polymerization step of ethylene polymer (A-13)) An ethylene-based polymer (A-13) was obtained in the same manner as in the production of the ethylene-based polymer (A-9) in Comparative Example 1, except that in the polymerization step, the hydrogen concentration relative to the gaseous ethylene was adjusted to 48 mol%, 1-butene was introduced from the gaseous phase at 2 mol% relative to the ethylene, the catalyst temperature was set to 3°C, the feed linear velocity was set to 2.0 m / s, and the temperature of the hexane containing dissolved ethylene was set to 3°C. The density was 947 kg / m 3 The MFR was 10g / 10min. For the microporous membrane of Comparative Example 5, an ethylene polymer (A-13) and an ethylene polymer (B-5) were used, and a microporous polyethylene resin composition was obtained in the same manner as in Comparative Example 1, except that 75 parts by mass of the ethylene polymer (A-13) and 25 parts by mass of the ethylene polymer (B-5) were used, totaling 100 parts by mass. The measurement and evaluation results are shown in Table 2.

[0215] [Table 1]

[0216] [Table 2] [Industrial Applicability]

[0217] The polyethylene composition of the present invention is particularly useful as a raw material for separators because it can impart excellent strength and fuse performance when processed into separators and has good slit processability.

Claims

1. The weight average molecular weight (Mw) is 250,000 or more and 1,000,000 or less, A polyethylene resin composition having a molecular weight distribution (Mw / Mn) of 2 or more and 18 or less, The polyethylene resin composition comprises Compositions comprising ethylene homopolymers and copolymers of ethylene and comonomers; Or a composition comprising two types of copolymers of ethylene and a comonomer, the comonomer is an α-olefin having 3 to 20 carbon atoms, When a solution of an extracted component obtained by temperature-increase free fractionation according to the "Conditions for temperature-increase free fractionation of polyethylene resin composition" in the "Condition 1" below is used as a solvent, the solution is subjected to cross-fractionation chromatography according to the "Conditions for CFC measurement of extracted component" in the "Condition 1" below, an integrated elution amount at 40°C or higher and lower than 90°C is 20% by mass or higher and lower than 60% by mass of the total elution amount; the integrated elution amount at 90°C or higher and 95°C or lower is 10% by mass or higher of the total elution amount, The temperature at which the maximum elution amount occurs is 88°C or higher and 100°C or lower, the polyethylene resin composition is subjected to temperature-increase free fractionation in accordance with the "conditions for temperature-increase free fractionation of polyethylene resin composition" in the following (Condition 1), and the extracted component has a comonomer content of 0.6 mol% or more as measured by C-NMR; Polyethylene resin composition. (Condition 1) "Temperature-increasing free fractionation conditions for polyethylene resin compositions" (1) Solvent: Toluene (2) Soxhlet extraction time: 6 hours (3) Method for collecting the components extracted into toluene solvent: Add methanol to the toluene solvent. The extract is then filtered off with suction to obtain the extract. "CFC measurement conditions for extracted components" (1) The o-dichlorobenzene solution of the extracted components is kept at 140°C for 120 minutes. (2) The temperature of the o-dichlorobenzene solution of the extracted components is lowered to 40°C at a rate of 0.5°C / min, and then maintained for 20 minutes. (3) Using the temperature program shown in (a) to (d) below, the column temperature is increased at a rate of 20°C / min. Each temperature is maintained for 21 minutes. (a) The temperature is increased from 40°C to 60°C in 10°C intervals. (b) The temperature is increased from 60°C to 69°C in 3°C intervals. (c) The temperature is increased from 69°C to 100°C in 1°C intervals. (d) The temperature is increased from 100°C to 120°C in 10°C intervals.

2. the polyethylene resin composition is subjected to temperature-increase free fractionation in accordance with the "conditions for temperature-increase free fractionation of polyethylene resin composition" in (Condition 1) above, and the extracted component has a comonomer content of 0.6 mol % or more and 5 mol % or less, as measured by C-NMR; The polyethylene resin composition according to claim 1.

3. the melting point of an extracted component obtained by subjecting the polyethylene resin composition to temperature-rise liberation fractionation in accordance with the "conditions for temperature-rise liberation fractionation of polyethylene resin composition" in (Condition 1) above is 125°C or higher and 135°C or lower; The polyethylene resin composition according to claim 1 or 2.

4. the lamellar thickness of an extracted component obtained by subjecting the polyethylene resin composition to temperature-increase liberation fractionation in accordance with the "conditions for temperature-increase liberation fractionation of polyethylene resin composition" in (Condition 1) above is 6 nm or more and 14 nm or less; The polyethylene resin composition according to any one of claims 1 to 3.

5. The polyethylene resin composition is heated to a temperature of 1000.degree. C. or less under the condition of "(Condition 1)" The lamellar thickness of the extracted components obtained by temperature-elevated liberation fractionation according to the "temperature-elevated liberation fractionation conditions" is 10 nm or more and 14 nm or less; The polyethylene resin composition according to any one of claims 1 to 4.

6. the weight average molecular weight (Mw) of an extracted component obtained by subjecting the polyethylene resin composition to temperature-increasing free fractionation in accordance with the "conditions for temperature-increasing free fractionation of polyethylene resin composition" in (Condition 1) above is 20,000 or more and 350,000 or less, and the molecular weight distribution (Mw / Mn) is 2 or more and 14 or less; The polyethylene resin composition according to any one of claims 1 to 5.

7. When a solution of an extracted component obtained by subjecting the polyethylene resin composition to temperature-increase free fractionation in accordance with the "Conditions for temperature-increase free fractionation of polyethylene resin composition" in (Condition 1) above is obtained using o-dichlorobenzene as a solvent, and CFC is measured in accordance with the "Conditions for CFC measurement of extracted component" in (Condition 1) above, the temperature at which the integrated elution amount reaches 10% by mass of the total elution amount is 70°C or higher and 90°C or lower; The polyethylene resin composition according to any one of claims 1 to 6.

8. the Ti content of an extractable component obtained by subjecting the polyethylene resin composition to temperature-elevation liberation fractionation in accordance with the "conditions for temperature-elevation liberation fractionation of polyethylene resin composition" in (Condition 1) above is 5 ppm or less; The polyethylene resin composition according to any one of claims 1 to 7.

9. the Al content of an extractable component obtained by subjecting the polyethylene resin composition to temperature-rise liberation fractionation in accordance with the "conditions for temperature-rise liberation fractionation of polyethylene resin composition" in (Condition 1) above is 10 ppm or less; The polyethylene resin composition according to any one of claims 1 to 8.

10. When a solution of the polyethylene resin composition using o-dichlorobenzene as a solvent was subjected to CFC measurement under the following conditions (Condition 2), an integrated elution amount at 40°C or higher and lower than 95°C is 15% by mass or higher and 70% by mass or lower of the total elution amount; an integrated elution amount at 95°C or higher and 105°C or lower is 15% by mass or higher of the total elution amount; It has at least two elution peaks, and the temperature at which the maximum elution amount occurs is 88°C or higher and 100°C or lower. The polyethylene resin composition according to any one of claims 1 to 9. (Condition 2) (1) The o-dichlorobenzene solution of the polyethylene resin composition is kept at 140° C. for 120 minutes. (2) The o-dichlorobenzene solution of the polyethylene resin composition is cooled to 40° C. at a rate of 0.5° C. / min, and then maintained at this temperature for 20 minutes. (3) Using the temperature program shown in (a) to (e) below, the column temperature is increased at a rate of 20°C / min. Each temperature is maintained for 21 minutes. (a) The temperature is increased from 40°C to 60°C in 10°C intervals. (b) The temperature is increased from 60°C to 75°C in 5°C intervals. (c) The temperature is increased from 75°C to 90°C in 3°C intervals. (d) The temperature is increased from 90°C to 110°C in 1°C intervals. (e) The temperature is increased from 110°C to 120°C in 5°C intervals.

11. The polyethylene resin composition has a Ti content of 5 ppm or less. The polyethylene resin composition according to any one of claims 1 to 10.

12. The polyethylene resin composition has an Al content of 10 ppm or less. The polyethylene resin composition according to any one of claims 1 to 11.

13. A microporous membrane for a separator comprising the polyethylene resin composition described in any one of claims 1 to 12.

14. A microporous membrane for a separator as described in claim 13, having a fuse temperature of less than 135°C.

15. A microporous membrane for a separator as described in claim 13 or 14, having a fuse speed of less than 10 seconds.

16. In a puncture test under the conditions of a needle tip curvature radius of 0.5 mm and a puncture speed of 2 mm / sec, the maximum puncture load is 3.0 N or more, the number of membrane defects present in an area of 250 mm x 250 mm of the microporous membrane for separator made of the polyethylene resin composition is 20 or less; The microporous membrane for a separator according to any one of claims 13 to 15.

17. The average film thickness is 5 μm or more and 30 μm or less, The variation is less than ±5 μm from the average film thickness. The microporous membrane for a separator according to any one of claims 13 to 16.

18. A method for producing a microporous membrane for a separator according to any one of claims 13 to 17, comprising: A wet method using a solvent includes an extrusion step, a stretching step, an extraction step, and a drying step, The extrusion step is a step of performing extrusion using an extruder equipped with a T-die. A method for manufacturing a microporous membrane for a separator.

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