JP6252322B2 - Stretched microporous membrane made of ultrahigh molecular weight polyethylene composition - Google Patents

Description

  The present invention relates to a stretched microporous membrane that uses an ultra-high molecular weight polyethylene composition and is excellent in moldability, strength, and heat resistance, and more specifically, because of its excellent strength and heat resistance, a permeable membrane, separation The present invention relates to a stretched microporous membrane made of an ultrahigh molecular weight polyethylene composition, which is expected to be applied as a membrane, a battery separator and the like.

  The ultra high molecular weight ethylene polymer has an extremely high molecular weight corresponding to a viscosity average molecular weight (Mv) of 1 million or more, so that it has impact resistance, self-lubricity, abrasion resistance, weather resistance, chemical resistance It has excellent physical properties and dimensional stability, and has high physical properties comparable to engineering plastics. For this reason, application to applications such as lining materials, food industry line parts, machine parts, artificial joints, sporting goods, and microporous membranes has been attempted by various molding methods.

  However, ultra-high molecular weight ethylene polymer has extremely low fluidity when melted due to its high molecular weight, and it can be molded by kneading extrusion like ordinary polyethylene having a molecular weight in the range of tens of thousands to about 500,000. Have difficulty. Therefore, ultrahigh molecular weight polyethylene is a method of directly sintering polymer powder obtained by polymerization, a method of compression molding, a molding method by a ram extruder that extrudes while intermittently compressing, a state where it is dispersed in a solvent, etc. After extrusion molding, a method such as a method of removing the solvent is performed.

  Among these, in the method of removing the solvent after extrusion molding in a state dispersed in a solvent or the like, it is known that a porous film can be produced by uniaxial or biaxial stretching before and after removing the solvent. ing. The ultrahigh molecular weight polyethylene microporous membrane is expected to have excellent physical properties such as heat resistance, strength, and impact resistance due to the high molecular weight of ultra high molecular weight polyethylene. However, the ultra-high molecular weight polyethylene produced by the Ziegler catalyst currently on the market has a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (molecular weight distribution) larger than 4, and the molecular weight distribution is wide. The strength and heat resistance of the molded body cannot be said to be sufficiently improved, and cannot be said to exhibit the expected performance.

  On the other hand, an ultrahigh molecular weight ethylene polymer having a narrow molecular weight distribution produced by using a metallocene catalyst or a post metallocene catalyst has also been proposed (see, for example, Patent Documents 1 and 2).

Japanese Patent No. 4868853 (see, for example, claims) Japanese Patent Laying-Open No. 2006-36988 (for example, refer to the claims)

  However, when a microporous film is produced using the ultrahigh molecular weight polyethylene proposed in Patent Documents 1 and 2, since the moldability is poor, it is difficult to stretch, and the performance is not sufficiently satisfactory.

  In addition, the ultra-high molecular weight polyethylene having a narrow molecular weight distribution has a higher melt viscosity than the ultra-high molecular weight polyethylene having a wide molecular weight distribution produced in the presence of a Ziegler catalyst or the like, and has a problem in molding processability. In compression molding, since the fusion property is inferior and grain boundaries remain, there is a problem that the molded product cannot exhibit the original physical properties of the resin. In addition, in the method in which ultra-high molecular weight polyethylene is extruded in a state of being dispersed in a solvent and then the solvent is removed to obtain a molded product, it is difficult to prepare a uniform gel, and the viscosity of the obtained gel is increased. The problem was in productivity because the countermeasure was taken by reducing the concentration of ultrahigh molecular weight polyethylene.

  Then, this invention is made | formed in view of the said subject, and it aims at providing the extending | stretching microporous film made from an ultrahigh molecular weight polyethylene composition excellent in intensity | strength and heat resistance.

  As a result of diligent research to solve the above-mentioned problems, the present inventors have blended ultra-high molecular weight polyethylenes having different characteristics, and have excellent moldability, high mechanical strength, and excellent heat resistance. The inventors have found that a stretched microporous membrane using a molecular weight polyethylene composition is excellent in strength and heat resistance, and completed the present invention.

That is, the present invention provides an ultrahigh molecular weight having an intrinsic viscosity of 7 dl / g or more and 35 dl / g or less measured under the following measurement condition (1) and a stress at break (MTS) of 1 MPa or less when melt stretched at 150 ° C. Ultra high with an intrinsic viscosity of 15 dl / g or more and 60 dl / g or less measured at the following measurement condition (1) and a stress at break when melt stretched at 150 ° C. of 2 MPa or more with respect to 100 parts by weight of polyethylene (A) The present invention relates to a stretched microporous membrane made of an ultrahigh molecular weight polyethylene composition, characterized by using an ultrahigh molecular weight polyethylene composition containing 5 parts by weight or more and 900 parts by weight or less of molecular weight polyethylene (B).
Measurement condition (1): Measured with an Ubbelohde viscometer using orthodichlorobenzene as a solvent at 135 ° C. with an ultrahigh molecular weight polyethylene concentration of 0.005 wt%.

  The present invention is described in detail below.

  The stretched microporous membrane made of an ultrahigh molecular weight polyethylene composition of the present invention has an ultrahigh molecular weight having an intrinsic viscosity of 7 dl / g or more and 35 dl / g or less and a stress at break (MTS) of 1 MPa or less when melt stretched at 150 ° C. Ultra high molecular weight polyethylene (B) having an intrinsic viscosity of 15 dl / g or more and 60 dl / g or less and a stress at break when melt stretched at 150 ° C. of 2 MPa or more with respect to 100 parts by weight of polyethylene (A) is 900 parts by weight or more and 900 An ultrahigh molecular weight polyethylene composition comprising no more than parts by weight is used.

  The ultra high molecular weight polyethylene (A) constituting the ultra high molecular weight polyethylene composition used for the stretched microporous membrane made of the ultra high molecular weight polyethylene composition of the present invention has an intrinsic viscosity of 7 dl / g or more and 35 dl / g or less, and melts at 150 ° C. It is an ultrahigh molecular weight polyethylene having a stress at break (MTS) of 1 MPa or less when stretched.

  The ultrahigh molecular weight polyethylene (A) has an intrinsic viscosity ([η]) of 7 dl / g or more and 35 dl / g or less, and becomes an ultrahigh molecular weight polyethylene composition particularly excellent in moldability, so that it is 7 dl / g or more and 25 dl / g. g or less is preferable. Here, when the intrinsic viscosity is less than 7 dl / g, the obtained stretched microporous film is inferior in mechanical properties and heat resistance. On the other hand, when the intrinsic viscosity exceeds 35 dl / g, the fluidity when melted is low, so that the molding processability is poor. The intrinsic viscosity ([η]) in the present invention is a solution having a polymer concentration of 0.0005 to 0.01% using, for example, an Ubbelohde viscometer, using orthodichlorobenzene, decahydronaphthalene, tetrahydronaphthalene or the like as a solvent. It is possible to measure by the method of measuring at 135 ° C.

  The ultra high molecular weight polyethylene (A) has a stress at break (MTS) of 1 MPa or less when melt-drawn at 150 ° C. Here, when the pressure exceeds 1 MPa, the resulting composition becomes a stretched microporous membrane having poor fluidity and moldability and poor molding appearance. In addition, as a measuring method of the stress at the time of melt drawing, for example, a test piece such as a strip shape or a dumbbell shape having a thickness of 0.1 to 5 mm and a width of 1 to 50 mm, 150 ° C., a tensile speed of 1 mm / min to 500 mm The test piece at that time can be prepared from a heat-compressed sheet formed by heat-compression molding under the conditions of a press temperature of 100 to 250 ° C. and a press pressure of 5 to 50 MPa, for example. . In addition, when strain hardening occurs and stress increases with stretching, the maximum value is the stress at break, and when strain hardening does not occur and stress does not increase after stretching, the stress in the flat region after yielding is calculated. The stress at break was taken.

  The ultra high molecular weight polyethylene (A) belongs to a category called ultra high molecular weight polyethylene, for example, ultra high molecular weight ethylene homopolymer; ultra high molecular weight ethylene-propylene copolymer, ultra high molecular weight ethylene. -1-butene copolymer, ultrahigh molecular weight ethylene-1-hexene copolymer, ultrahigh molecular weight ethylene-1-α-olefin copolymer such as ethylene-1-octene copolymer; it can. The ultra high molecular weight polyethylene (A) may be in any shape such as particles, pellets, sheets, and lumps. Among them, the composition obtained is excellent in productivity when making an ultra high molecular weight polyethylene composition. Since the material is also excellent in physical properties and moldability, those having an average particle size of 1-1000 μm are preferred. The average particle size can be measured by a method such as a sieving test method using a standard sieve defined in JIS Z8801, for example.

  The ultra high molecular weight polyethylene (A) can be produced, for example, by homopolymerizing ethylene or copolymerizing ethylene and α-olefin in the presence of a Ziegler catalyst or a Philips catalyst. Examples of the α-olefin include propylene, 1-butene, 1-hexene and 1-octene.

  The Ziegler catalyst in that case may be one generally known as a Ziegler catalyst used for the coordination polymerization of ethylene and α-olefin, such as a catalyst containing a titanium compound and an organoaluminum compound, and a titanium halide compound. And a catalyst comprising an organoaluminum compound, a solid catalyst component comprising titanium, magnesium, chlorine, etc., and a catalyst comprising an organoaluminum compound. More specifically, as such a catalyst, a catalyst component (a) obtained by reacting a titanium compound with a reaction product of an alcohol pretreated product of anhydrous magnesium dihalide and an organometallic compound, and an organometallic compound ( b) a catalyst (for example, a catalyst described in JP-A-49-119980), a magnesium metal and an oxygen-containing organic compound such as a hydroxylated organic compound or magnesium, an oxygen-containing organic compound of a transition metal, and an aluminum halide A catalyst comprising a catalyst component (A) obtained by reacting the catalyst and a catalyst component (B) of an organometallic compound (for example, a catalyst described in JP-B-52-15110), (i) magnesium metal and organic hydroxide At least one member selected from a compound, an oxygen-containing organic compound of magnesium, and a halogen-containing compound; (ii) (Iii) a reaction product obtained by reacting a silicon compound with at least one member selected from an oxygen-containing organic compound and a halogen-containing compound of a transfer metal; and (iv) a solid catalyst component obtained by reacting an aluminum halide compound ( Examples thereof include a catalyst comprising A) and a catalyst component (B) of an organometallic compound (for example, a catalyst described in JP-B-62-58367).

  Further, the Phillips catalyst may be one generally known as a Phillips catalyst used for the coordination polymerization of ethylene and α-olefin, for example, a catalyst system containing a chromium compound such as chromium oxide. Specifically, Examples thereof include catalysts in which chromium oxides such as chromium trioxide and chromate are supported on solid oxides such as silica, alumina, silica-alumina, silica-titania (for example, JP-A-53-91092). And a catalyst described in Japanese Patent Publication No. 47-1766).

  Ultra high molecular weight polyethylene produced using these catalysts contains metal components derived from the residues of the catalyst used, such as titanium, magnesium, chlorine, etc. if it is ultra high molecular weight polyethylene produced in the presence of a Ziegler catalyst. In the case of ultra high molecular weight polyethylene produced in the presence of a Philips catalyst, components such as chromium, silicon and aluminum are included. Ultra high molecular weight polyethylene produced using these catalysts has a wide molecular weight distribution (ratio of molecular weight distribution of weight average molecular weight (Mw) and number average molecular weight (Mn) (Mw / Mn) is 4 or more), and molecular weight. Even if it is high, the viscosity is relatively low.

  Further, the ultra high molecular weight polyethylene (A) can provide an ultra high molecular weight polyethylene composition excellent in molding processability because the molecular weight distribution is moderately wide, and the obtained stretched microporous film has an appearance, Since it will also be excellent in color tone and weather resistance, it is preferable to contain titanium or chromium in a range of 0.2 ppm to 50 ppm. The content of titanium or chromium can be determined by measurement using a chemical titration method, a fluorescent X-ray analyzer, an ICP emission analyzer, or the like.

  The ultra high molecular weight polyethylene (A) may be a commercially available product, for example, (trade name) GUR4113, GUR4120, GUR4130 (above, manufactured by Ticona), (trade name) Sunfine UH900, Sun Fine UH950 (above, manufactured by Asahi Kasei Chemicals Co., Ltd.), (trade name) Hi-Zex Million 240M, Hi-Zex Million 340M (above, manufactured by Mitsui Chemicals, Inc.) and the like can be mentioned.

  The ultra high molecular weight polyethylene (B) constituting the ultra high molecular weight polyethylene composition used for the stretched microporous membrane made of the ultra high molecular weight polyethylene composition of the present invention has an intrinsic viscosity of 15 dl / g to 60 dl / g and melts at 150 ° C. It is an ultra high molecular weight polyethylene having a stress at break when stretched of 2 MPa or more.

  The ultra high molecular weight polyethylene (B) has an intrinsic viscosity ([η]) of 15 dl / g or more and 60 dl / g or less, and is particularly excellent in mechanical strength and heat resistance when formed into a stretched microporous film. From 20 dl / g to 50 dl / g. Here, when the intrinsic viscosity is less than 15 dl / g, the resulting composition and porous film are inferior in mechanical properties and heat resistance. On the other hand, when the intrinsic viscosity exceeds 60 dl / g, the flowability when melted is low, so that the moldability is very poor.

  The ultra high molecular weight polyethylene (B) has a stress at break (MTS (MPa) of 2 MPa or more when melt-drawn at 150 ° C., and is particularly excellent in heat resistance. Here, when the stress at break when melt stretched at 150 ° C. is less than 2 MPa, the content of the component having a relatively low molecular weight increases, The resulting stretched microporous membrane is inferior in heat resistance, and the general polyethylene having a molecular weight of 500,000 or less has high fluidity at 150 ° C., and its molded body is deformed by its own weight. In addition, as a method for measuring the stress at break during melt drawing, for example, a strip or dumbbell-type test piece having a thickness of 0.1 to 5 mm and a width of 1 to 50 mm is used. And a method of stretching at a tensile speed of 1 mm / min to 500 mm / min. The test piece at that time is heated and compressed under conditions of a press temperature of 100 to 250 ° C. and a press pressure of 5 to 50 MPa, for example. It can be made from a heat-compressed sheet that has been molded, and when strain hardening occurs and stress increases with stretching, the maximum value is the stress at break, strain hardening does not occur, and stress increases even when stretched. If not, the stress in the flat region after yielding was taken as the stress at break.

As the ultrahigh molecular weight polyethylene (B), it is possible to provide a stretched microporous film having excellent operability when making an ultrahigh molecular weight polyethylene composition, and particularly excellent in appearance and physical properties. It is preferably in the form of particles of 130 kg / m ³ or more and 700 kg / m ³ or less, particularly 200 kg / m ³ or more and 600 kg / m ³ or less. The bulk density can be measured by a method based on, for example, JIS K6760 (1995).

The ultra high molecular weight polyethylene (B) is a stretched microporous film made of an ultra high molecular weight polyethylene composition having an excellent balance of heat resistance, mechanical strength, and moldability. The melting point (Tm ₁ ) of the 1st scan when the temperature is raised from 0 ° C. to 230 ° C. at the rate of 10 ° C./min (1st scan), then left for 5 minutes, and then at the rate of temperature drop of 10 ° C./min. Decrease the temperature to -20 ° C, leave it for 5 minutes, and then measure the melting point (Tm ₂ ) of 2nd scan when the temperature is raised from -20 ° C to 230 ° C (2nd scan) again at a rate of 10 ° C / min. The difference between Tm ₁ and Tm ₂ (ΔTm = Tm ₁ −Tm ₂ ) is preferably 11 ° C. or higher and 30 ° C. or lower, and particularly preferably ΔTm is 11 ° C. or higher and 15 ° C. or lower. Here, since the molecular chains of polyethylene are highly crystallized due to orientation or the like, ΔTm which is a difference between Tm ₁ and Tm ₂ when measured with a differential scanning calorimeter (DSC) is 11 I think that it will be a very big difference of not less than 30 ° C.

The ultrahigh molecular weight polyethylene (B) is a stretched microporous film made of an ultrahigh molecular weight polyethylene composition that is particularly excellent in heat resistance. Therefore, the stress at break when melt stretched at 150 ° C. (MTS (MPa)). ) And the intrinsic viscosity ([η]) preferably satisfy the following relational expression (a). In particular, since the ultrahigh molecular weight polyethylene composition is excellent in melt stretchability and moldability, the following relational expression It is preferable to satisfy (c).
MTS ≧ 0.11 × [η] (a)
0.11 × [η] ≦ MTS ≦ 0.32 × [η] (c)
As the ultra-high molecular weight polyethylene (B), it becomes possible to provide a tougher stretched microporous membrane. Therefore, after heating and compressing at a press temperature of 190 ° C. and a press pressure of 20 MPa, the 2nd scan measured above is performed. It is preferable that the tensile strength at break (TS (MPa)) of the sheet formed by cooling at a mold temperature 10 ° C. to 30 ° C. lower than the melting point (Tm ₂ ) satisfies the following relational expression (b). Therefore, it is possible to provide a stretched microporous membrane that is tough and excellent in mechanical strength and wear resistance, and therefore preferably satisfies the following relational expression (d). There are no particular limitations on the measurement conditions of the tensile strength at this time, and for example, test pieces such as strips having a thickness of 0.1 to 5 mm and a width of 1 to 50 mm, dumbbells, and the like, with a tensile speed of 1 mm / min to 500 mm / min. A method of measuring at a speed of can be exemplified.
TS ≧ 1.35 × Tm ₂ −130 (b)
1.35 × Tm ₂ −130 ≦ TS ≦ 2 × Tm ₂ −175 (d)
As the ultrahigh molecular weight polyethylene (B), since it becomes a stretched microporous film made of an ultrahigh molecular weight polyethylene composition having excellent color tone, heat resistance, and weather resistance, the content of both titanium and chromium is 0.2 ppm or less, Is preferably below the detection limit.

  Further, the ultra high molecular weight polyethylene (B) may be in any shape such as particulate, pellet, sheet, and lump, and among them, it is easy to mix in the composition, and uniform ultra high molecular weight polyethylene. Since it becomes possible to obtain a composition easily, the average particle diameter is preferably 1 μm or more and 1000 μm or less. The average particle size can be measured by a method such as a sieving test method using a standard sieve defined in JIS Z8801, for example.

  The ultra-high molecular weight polyethylene (B) is, for example, a homopolymer of ethylene in the presence of a transition metal compound such as a metallocene compound or a half metallocene compound, or a metallocene catalyst containing a component supported on a carrier, or ethylene and The α-olefin can be produced by copolymerization. Examples of the α-olefin in this case include propylene, 1-butene, 1-hexene, 1-octene and the like. As the transition metal compound constituting the metallocene catalyst at that time, for example, a complex having any two of substituted or unsubstituted cyclopentadienyl group, indenyl group and fluorenyl group whose central metal is zirconium, hafnium or the like is used. A metallocene complex, a half metallocene complex which is a complex having any one of a cyclopentadienyl group, an indenyl group and a fluorenyl group, a transition metal compound having a phenoxyimine ligand, a transition metal having a phenolate ether ligand Examples thereof include compounds (for example, transition metal compounds used in JP-A-9-291112, JP-A-11-106417, JP-A-4139341, JP2013-529721). The metallocene catalyst may be a combination of these transition metal compounds and aluminoxane, Lewis acidic or anionic boron compounds, organic modified clays modified with aliphatic salts, organoaluminum compounds, etc., or these And catalysts supported on inorganic oxides, polymer particles, and the like. Examples of the polymerization method include a solution polymerization method, a bulk polymerization method, a gas phase polymerization method, a slurry polymerization method, and the like, and among them, an ultra high molecular weight polyethylene (B) having a particularly well-defined particle shape. Ultra-high molecular weight polyethylene (B) that can be produced, and can provide a stretched microporous film having a high melting point and high crystallinity, and excellent mechanical strength, heat resistance, and abrasion resistance can be efficiently and stably produced. The slurry polymerization method is preferable because it can be produced. Further, the solvent used in the slurry polymerization method may be any organic solvent that is generally used, such as benzene, toluene, xylene, pentane, hexane, heptane, etc., and liquefied gas such as isobutane and propane, Olefins such as propylene, 1-butene, 1-octene and 1-hexene can also be used as a solvent.

  Specific examples of the metallocene catalyst suitable for producing the ultrahigh molecular weight polyethylene (B) include, for example, at least a transition metal compound (a), an organic modified clay (b) modified with an aliphatic salt, and an organic aluminum. The metallocene catalyst obtained from a compound (c) can be mentioned.

  Examples of the transition metal compound (a) include a transition metal compound having a (substituted) cyclopentadienyl group and a (substituted) fluorenyl group, and a transition having a (substituted) cyclopentadienyl group and a (substituted) indenyl group. Metal compounds, transition metal compounds having a (substituted) indenyl group and a (substituted) fluorenyl group can be exemplified, and examples of the transition metal in this case include zirconium, hafnium, etc. Among them, ultra high molecular weight Since it becomes possible to efficiently produce polyethylene (B), a zirconium compound having a (substituted) cyclopentadienyl group and an amino group-substituted fluorenyl group, a (substituted) cyclopentadienyl group and an amino group-substituted fluorenyl group It is preferable that it is a hafnium compound having.

  More specifically, for example, diphenylmethylene (1-indenyl) (9-fluorenyl) zirconium dichloride, diphenylmethylene (1-indenyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, diphenyl Methylene (4-phenyl-1-indenyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, diphenylsilanediyl (cyclopentadienyl) (2- (dimethylamino) -9-fluorenyl) zirconium Dichloride, diphenylsilanediyl (cyclopentadienyl) (2- (diethylamino) -9-fluorenyl) zirconium dichloride, diphenylsilanediyl (cyclopentadienyl) (2- (dibenzylamino) -9-fluorenyl) zyl Nium dichloride, diphenylsilanediyl (cyclopentadienyl) (2,7-bis (dimethylamino) -9-fluorenyl) zirconium dichloride, diphenylsilanediyl (cyclopentadienyl) (2,7-bis (diethylamino) -9 -Fluorenyl) zirconium dichloride, diphenylsilanediyl (cyclopentadienyl) (2,7-bis (dibenzylamino) -9-fluorenyl) zirconium dichloride, diphenylsilanediyl (cyclopentadienyl) (4- (dimethylamino) -9-fluorenyl) zirconium dichloride, diphenylsilanediyl (cyclopentadienyl) (4- (diethylamino) -9-fluorenyl) zirconium dichloride, diphenylsilanediyl (cyclopentadiyl) Nyl) (4- (dibenzylamino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (2- (dimethylamino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) ( 2- (diethylamino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (2- (dibenzylamino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (2,7- Bis (dimethylamino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (2,7-bis (diethylamino) -9-fluorenyl) zirconium dichloride, diphenyl Methylene (cyclopentadienyl) (2,7-bis (dibenzylamino) -9-fluorenyl) zirconium dichloride diphenylmethylene (cyclopentadienyl) (4- (dimethylamino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (Cyclopentadienyl) (4- (diethylamino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (4- (dibenzylamino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadi) Enyl) (2,7-bis (dimethylamino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (2,7-bis (diethylamino) -9-fluorenyl) zyl Nium dichloride, diphenylmethylene (cyclopentadienyl) (2,7-bis (diisopropylamino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (2,7-bis (di-n-butyl- Amino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (2,7-bis (dibenzylamino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (3,6- Bis (dimethylamino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (3,6-bis (diethylamino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclope Tadienyl) (3,6-bis (di-n-propyl-amino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (2,5-bis (dimethylamino) -9-fluorenyl) zirconium dichloride Diphenylmethylene (cyclopentadienyl) (2,5-bis (diethylamino) -9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (2,5-bis (diisopropylamino) -9-fluorenyl) zirconium Zirconium compounds such as dichloride; zirconium compounds obtained by converting these dichloro compounds to dimethyl, diethyl, dihydro, diphenyl, and dibenzyl compounds, and hafnium compounds obtained by converting zirconium of these compounds to hafnium A thing etc. can be illustrated.

  Examples of the organically modified clay (b) modified with the aliphatic salt include N, N-dimethyl-behenylamine hydrochloride, N-methyl-N-ethyl-behenylamine hydrochloride, and N-methyl-N—. n-propyl-behenylamine hydrochloride, N, N-dioleyl-methylamine hydrochloride, N, N-dimethyl-behenylamine hydrofluoride, N-methyl-N-ethyl-behenylamine hydrofluoride, N-methyl-Nn-propyl-behenylamine hydrofluorate, N, N-dioleyl-methylamine hydrofluoride, N, N-dimethyl-behenylamine hydrobromide, N-methyl- N-ethyl-behenylamine hydrobromide, N-methyl-Nn-propyl-behenylamine hydrobromide, N, N-dioleyl-methylamine hydrobromide, N, N-dimethyl -Behenylamine hydroiodide, N-methyl-N-ethyl-behenylamine hydroiodide, N-methyl-Nn-propyl-behenylamine hydroiodide, N, N-dioleyl-methyl Amine hydroiodide, N, N-dimethyl-behenylamine sulfate, N-methyl-N-ethyl-behenylamine sulfate, N-methyl-Nn-propyl-behenylamine sulfate, N, N- Aliphatic amine salts such as dioleyl-methylamine sulfate; P, P-dimethyl-behenylphosphine hydrochloride, P, P-diethyl-behenylphosphine hydrochloride, P, P-dipropyl-behenylphosphine hydrochloride, P, P- Dimethyl-behenylphosphine hydrofluoride, P, P-diethyl-behenylphosphine hydrofluoride, P, P-dipropyl-behenylphosphite Hydrofluoride, P, P-dimethyl-behenylphosphine hydrobromide, P, P-diethyl-behenylphosphine hydrobromide, P, P-dipropyl-behenylphosphine hydrobromide, P, P-dimethyl-behenylphosphine hydroiodide, P, P-diethyl-behenylphosphine hydroiodide, P, P-dipropyl-behenylphosphine hydroiodide, P, P-dimethyl-behenylphosphine sulfate And an aliphatic phosphonium salt such as P, P-diethyl-behenylphosphine sulfate and P, P-dipropyl-behenylphosphine sulfate;

The clay compound constituting the organically modified clay (b) may be any clay compound as long as it belongs to the category of clay compounds, and is generally a tetrahedral sheet in which a silica tetrahedron is continuous in two dimensions. A layer called a silicate layer formed by combining an octahedron sheet in which alumina octahedrons, magnesia octahedrons, and the like are two-dimensionally combined in a 1: 1 or 2: 1 layer is formed to overlap. Part of the silica tetrahedron Si is Al, alumina octahedron Al is Mg, and magnesia octahedron Mg is isomorphously substituted with Li, etc., resulting in a lack of positive charge inside the layer and negative charge as a whole layer. In order to compensate for this negative charge, it is known that cations such as Na ⁺ and Ca ²⁺ exist between the layers. As the clay compound, kaolinite, talc, smectite, vermiculite, mica, brittle mica, curdstone and the like as natural products or synthetic products exist, and these can be used. Smectite is preferable from the viewpoint of easiness of modification and organic modification, and hectorite or montmorillonite is more preferable among smectites.

  The organically modified clay (b) can be obtained by introducing the aliphatic salt between layers of the clay compound to form an ionic complex. In preparing the organically modified clay (b), it is preferable to carry out the treatment by selecting conditions of a clay compound concentration of 0.1 to 30% by weight and a treatment temperature of 0 to 150 ° C. The aliphatic salt may be prepared as a solid and dissolved in a solvent for use, or a solution of the aliphatic salt may be prepared by a chemical reaction in the solvent and used as it is. Regarding the reaction amount ratio between the clay compound and the aliphatic salt, it is preferable to use an aliphatic salt having an equivalent amount or more with respect to exchangeable cations of the clay compound. Examples of the processing solvent include aliphatic hydrocarbons such as pentane, hexane and heptane; aromatic hydrocarbons such as benzene and toluene; alcohols such as ethyl alcohol and methyl alcohol; ethers such as ethyl ether and n-butyl ether. Halogenated hydrocarbons such as methylene chloride and chloroform; acetone; 1,4-dioxane; tetrahydrofuran; water; Preferably, alcohols or water is used alone or as one component of a solvent.

  Moreover, there is no restriction | limiting in the particle size of this organic modified clay (b), and since it will become excellent in the efficiency at the time of catalyst preparation and the efficiency at the time of polyethylene manufacture among them, it is preferable that it is 1-100 micrometers. There is no limitation on the method of adjusting the particle size at that time, and large particles may be pulverized to an appropriate particle size, small particles may be granulated to an appropriate particle size, or pulverization and granulation May be combined. The particle size may be adjusted on the clay before organic modification or on the organic modified clay after modification.

  Any organoaluminum compound (c) may be used as long as it belongs to the category called organoaluminum compound, and examples thereof include alkylaluminums such as trimethylaluminum, triethylaluminum, and triisobutylaluminum. Can do.

  The transition metal compound (a) (hereinafter also referred to as component (a)), the organically modified clay (b) (hereinafter also referred to as component (b)), and the organoaluminum compound (c) ( Hereinafter, the use ratio of (c) component) is not subject to any limitation, and among these, a metallocene catalyst capable of producing an ultrahigh molecular weight polyethylene (B) particularly efficiently. Therefore, the molar ratio of the component (a) to the component (c) per metal atom is preferably in the range of (a) component: (c) component = 100: 1 to 1: 100000, particularly 1: It is preferable that it is the range of 1-1: 10000. The weight ratio of the component (a) to the component (b) is preferably (a) component: (b) component = 10: 1 to 1: 10000, particularly in the range of 3: 1 to 1: 1000. It is preferable. As for the method for preparing the metallocene-based catalyst, any method may be used as long as it is possible to prepare a catalyst containing the component (a), the component (b) and the component (c). Examples thereof include a method in which the components (a), (b) and (c) are mixed in an inert solvent or using a monomer for polymerization as a solvent. Moreover, there is no restriction | limiting also about the order which makes these components react, and the temperature and processing time which perform this process also have no restriction | limiting. It is also possible to prepare a metallocene catalyst by using two or more of each of the component (a), the component (b), and the component (c).

  Polymerization conditions such as a polymerization temperature, a polymerization time, a polymerization pressure, and a monomer concentration in producing the ultrahigh molecular weight polyethylene (B) can be arbitrarily selected. Among them, a polymerization temperature of 0 to 100 ° C., a polymerization time of 10 It is preferable to carry out in the range of second to 20 hours, polymerization pressure normal pressure to 100 MPa. It is also possible to adjust the molecular weight using hydrogen during polymerization. The polymerization can be carried out by any of batch, semi-continuous and continuous methods, and can be carried out in two or more stages by changing the polymerization conditions. The ultrahigh molecular weight polyethylene (B) obtained after the completion of the polymerization can be obtained by separating and recovering from the polymerization solvent by a conventionally known method and drying it.

  The ultra high molecular weight polyethylene composition constituting the stretched microporous membrane made of the ultra high molecular weight polyethylene composition of the present invention is 5 parts by weight of the ultra high molecular weight polyethylene (B) with respect to 100 parts by weight of the ultra high molecular weight polyethylene (A). It is 900 parts by weight or less, preferably 20 parts by weight or more and 400 parts by weight or less. Here, when the ultra high molecular weight polyethylene (B) is less than 5 parts by weight, the mechanical strength and heat resistance of the microporous film are lowered. On the other hand, when the ultra high molecular weight polyethylene (B) exceeds 900 parts by weight, the smoothness of the microporous membrane is impaired, the solubility in a solvent is lowered, the viscosity of the ultra high molecular weight polyethylene composition solution is increased, etc. It has a problem.

  As a method for preparing the ultra high molecular weight polyethylene composition, it is possible to obtain an ultra high molecular weight polyethylene composition by mixing ultra high molecular weight polyethylene (A) and ultra high molecular weight polyethylene (B). Any method may be used, for example, after extrusion kneading in a molten state, roll kneading, or after dissolving in a solvent to form a solution, extrusion kneading, roll kneading, or stirring and mixing using a stirring blade And a method of removing the solvent by solvent distillation, solvent extraction, and the like. Moreover, when melt | dissolving in an organic solvent, it can also be used for the mixed reaction with the organic solvent mentioned later to use the obtained mixture as it is. Examples of the solvent used here include linear or branched saturated or unsaturated aliphatic compounds such as hexane, heptane, decane, dodecane, tetradecane, octadecane, eicosane, liquid paraffin, and isoparaffin; cyclohexane, cyclodecane, and tetrahydronaphthalene. Saturated or unsaturated alicyclic compounds such as decahydronaphthalene; aromatic compounds such as benzene, toluene, xylene, naphthalene, anthracene; methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, chlorobenzene, And halogenated hydrocarbon compounds such as dichlorobenzene.

  And since the ultrahigh molecular weight polyethylene composition is more excellent in heat resistance when formed into a stretched microporous film, the stress at break when melt stretched at 150 ° C. is 1.2 MPa or more, particularly 1. It is preferably 5 MPa or more, more preferably 2 MPa or more. Moreover, as a measuring method of the stress at the time of melt drawing, for example, a test piece such as a strip shape or a dumbbell shape having a thickness of 0.1 to 5 mm and a width of 1 to 50 mm is used at 150 ° C. and a tensile speed of 1 mm / min to 500 mm. The test piece at that time can be prepared from a heat-compressed sheet formed by heat-compression molding under the conditions of a press temperature of 100 to 250 ° C. and a press pressure of 5 to 50 MPa, for example. . In addition, when strain hardening occurs and stress increases with stretching, the maximum value is the stress at break, and when strain hardening does not occur and stress does not increase after stretching, the stress in the flat region after yielding is calculated. The stress at break was taken.

  In addition, the ultrahigh molecular weight polyethylene composition constituting the stretched microporous membrane made of the ultrahigh molecular weight polyethylene composition of the present invention contains various known additives as necessary without departing from the object of the present invention. Heat stabilizers such as tetrakis (methylene (3,5-di-t-butyl-4-hydroxy) hydrocinnamate) methane, distearyl thiodipropionate; bis (2,2 ′, 6,6 And weathering stabilizers such as' -tetramethyl-4-piperidine) sebacate and 2- (2-hydroxy-t-butyl-5-methylphenyl) -5-chlorobenzotriazole. Further, an inorganic or organic dry color may be added as a colorant. Furthermore, stearates such as calcium stearate known as lubricants and hydrogen chloride absorbents may be added. These additives may be those added to ultrahigh molecular weight polyethylene (A) and ultrahigh molecular weight polyethylene (B).

The stretched microporous membrane made of the ultrahigh molecular weight polyethylene composition of the present invention preferably has a porosity of 10 to 90%, particularly 25 to 80%. If the porosity is less than 10%, the permeation resistance increases, and if it exceeds 90%, the strength and rigidity are lowered, which is not preferable. The film thickness is preferably 0.001 to 1 mm and the average pore diameter is 1 to 1000 nm. The porosity in the present invention is, for example, porosity (V,%) = 100−10 × (weight of stretched microporous membrane of 10 cm × 10 cm) (W, g) / (true density of stretched microporous membrane (g / cm ³ ) × stretched microporous membrane thickness (d, mm)). The film thickness (mm) of the stretched microporous film can be determined, for example, by measuring the film thickness with a contact-type film thickness meter at 30 points of the stretched microporous film. The average pore diameter can be obtained by image analysis from an image obtained by observation with a scanning electron microscope in addition to the nitrogen adsorption method and the mercury intrusion method.

  In addition, the stretched microporous membrane made of the ultrahigh molecular weight polyethylene composition of the present invention preferably has a stretch ratio of 2 to 20 times in the longitudinal direction and 2 to 20 times in the transverse direction.

  Next, the manufacturing method of the extending | stretching microporous film made from the ultra high molecular weight polyethylene composition of this invention is demonstrated. The method for producing the stretched microporous membrane made of the ultrahigh molecular weight polyethylene composition of the present invention is not particularly limited. For example, the ultrahigh molecular weight polyethylene composition and an organic solvent are mixed at a temperature of 50 ° C. or higher and 300 ° C. or lower to form a sheet. Examples of the method include a step of removing an organic solvent from the sheet-like material and a step of biaxial stretching. In addition, when the ultrahigh molecular weight polyethylene composition and the organic solvent are mixed, as described above, the ultrahigh molecular weight polyethylene (A), the ultrahigh molecular weight polyethylene (B), and the organic solvent are mixed to form the ultrahigh molecular weight polyethylene. It is also possible to use the one in preparing the composition.

  Examples of the organic solvent used here include linear or branched saturated or unsaturated aliphatic compounds such as hexane, heptane, decane, dodecane, tetradecane, octadecane, eicosane, liquid paraffin, and isoparaffin; cyclohexane, cyclodecane, tetrahydro Saturated or unsaturated alicyclic compounds such as naphthalene and decahydronaphthalene; aromatic compounds such as benzene, toluene, xylene, naphthalene and anthracene; methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, chlorobenzene And halogenated hydrocarbon compounds such as dichlorobenzene, higher alcohols having 5 or more carbon atoms; phthalates, or mixtures thereof. In addition, when the ultrahigh molecular weight polyethylene composition and the organic solvent are mixed, a stretched microporous film excellent in uniformity and smoothness can be obtained efficiently, so that the concentration of the ultrahigh molecular weight polyethylene composition is 0.5 wt% or more. It is preferably 60 wt% or less, particularly 5 wt% or more and 40 wt% or less. Then, when mixing the ultramolecular weight polyethylene composition and the organic solvent, for example, a method of mixing in a reaction vessel equipped with a stirring blade, a method of extrusion kneading with a single-screw or twin-screw extruder, a reactor Examples of the method include extrusion kneading after the mixing.

  And the obtained mixture is shape | molded as a sheet-like material containing an organic solvent, for example by methods, such as compression molding, the extrusion method from T-die, a circular die, and inflation molding.

  Further, as the step of removing the organic solvent from the sheet-like material, for example, a drying method by heating, a method of drying after solvent extraction with a low melting point aliphatic or alicyclic hydrocarbon, alcohol, halogenated hydrocarbon, etc. Can be illustrated. Examples of the biaxial stretching step include a step of performing a simultaneous biaxial stretching method, a sequential biaxial stretching method, and the like, and the stretching speed and stretching temperature at that time may be constant or multistage. Good. The stretching temperature is preferably 0 ° C. or higher and 200 ° C. or lower. The order of the organic solvent removal step and the biaxial stretching step is arbitrary, for example, biaxial stretching after the removal of the organic solvent, or removal of the organic solvent after the biaxial stretching, These may be performed simultaneously. Moreover, annealing can also be given after extending | stretching.

  The stretched microporous membrane made of an ultra-high molecular weight polyethylene composition of the present invention has a heat resistance stabilizer, weather resistance stabilizer, antistatic agent, anti-fogging agent, anti-blocking agent, slip agent, lubricant as long as it does not depart from the purpose of the present invention. , Nucleating agents, pigments, etc .; inorganic fillers or reinforcing agents such as carbon black, talc, glass powder, glass fibers, metal powders; organic fillers or reinforcing agents; flame retardants; known additives such as neutron shielding agents; Are high density polyethylene (HDPE), linear low density polyethylene (L-LDPE), low density polyethylene (LDPE), polypropylene resin, poly-1-butene, poly-4-methyl-1-pentene, ethylene Resin such as vinyl acetate copolymer, ethylene / vinyl alcohol copolymer, polystyrene, and maleic anhydride grafted product may be blended. Additives can be added as follows: Ultra high molecular weight polyethylene (A) and / or ultra high molecular weight polyethylene (B), ultra high molecular weight polyethylene composition, ultra high molecular weight polyethylene composition, molding The method of blending in the case of this, the method of carrying out dry blending or melt blending beforehand, etc. can be mentioned.

  Since the stretched microporous membrane made of an ultrahigh molecular weight polyethylene composition of the present invention is excellent in strength and heat resistance, a gas separation membrane, a gas permeable membrane, a tape, a tube, a lead storage battery, a nickel metal hydride battery, a lithium battery, a lithium ion battery, and the like. It can be used as a member such as a battery separator such as a secondary battery.

  The stretched microporous membrane made of an ultrahigh molecular weight polyethylene composition obtained by the present invention is excellent in strength and heat resistance, so that it is a gas separation membrane, a gas permeable membrane, a tape, a tube, a lead storage battery, a nickel hydride battery, a lithium battery, a lithium battery. It is suitably used for battery separators such as ion secondary batteries.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

  Unless otherwise noted, the reagents used were commercially available products or those synthesized according to known methods.

  A jet mill (manufactured by Seishin Enterprise Co., Ltd., (trade name) CO-JET SYSTEM α MARK III) was used for pulverizing the organically modified clay, and the particle size after pulverization was measured using a microtrack particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., (Trade name) MT3000) was used to measure ethanol as a dispersant.

  Preparation of the catalyst for polyethylene production, production of polyethylene and solvent purification were all carried out in an inert gas atmosphere. A hexane solution (20 wt%) of triisobutylaluminum manufactured by Tosoh Finechem Co., Ltd. was used.

  Furthermore, various physical properties of the ultrahigh molecular weight polyethylene in the examples were measured by the following methods.

~ Measurement of intrinsic viscosity ([η]) ~
Using an Ubbelohde viscometer, ODCB (orthodichlorobenzene) was used as a solvent at 135 ° C. with an ultrahigh molecular weight polyethylene concentration of 0.005 wt%.

~ Measurement of bulk density ~
It measured by the method based on JISK6760 (1995).

~ Measurement of Tm ₁ and Tm ₂ ~
Using a differential scanning calorimeter (DSC) (product name: DSC6220, manufactured by SII Nanotechnology Co., Ltd.), the temperature was raised from 0 ° C to 230 ° C at a rate of 10 ° C / min (1st scan). The crystal melting peak (Tm ₁ ) of 1st scan was measured. Then, after standing for 5 minutes, the temperature was lowered to −20 ° C. at a temperature lowering rate of 10 ° C./min. After standing for 5 minutes, the temperature was raised again from −20 ° C. to 230 ° C. at a temperature rising rate of 10 ° C./min (2nd scan). 2nd scan crystal melting peak (Tm ₂ ) was measured. The sample amount of ultra high molecular weight polyethylene at that time was 6 mg.

-Measurement of titanium content-
The ultra high molecular weight polyethylene was incinerated, alkali melted, and the prepared solution was used to determine the titanium content in the ultra high molecular weight polyethylene using an ICP emission analyzer (manufactured by PerkinElmer Co., Ltd., (trade name) Optima 3000XL). It was measured.

~ Measurement of average particle diameter ~
Each of the 9 types of sieves defined in JIS Z8801 (mesh openings: 710 μm, 500 μm, 425 μm, 300 μm, 212 μm, 150 μm, 106 μm, 75 μm, 53 μm) The average particle diameter was determined by measuring the particle diameter at 50% weight on an integral curve obtained by integrating the weight of the particles remaining on the sieve from the side having a large opening.

-Creation of evaluation sheets for ultra-high molecular weight polyethylene-
The evaluation sheet of ultra high molecular weight polyethylene was molded by the following method. That is, ultra high molecular weight polyethylene was sandwiched between polyethylene terephthalate films, preheated at 190 ° C. for 5 minutes, and then heat-rolled under conditions of 190 ° C. and a press pressure of 20 MPa. Thereafter, the mold was cooled at a mold temperature of 110 ° C. for 10 minutes to prepare a press sheet having a thickness of 0.3 mm.

-Measurement of film thickness and porosity of stretched microporous membrane-
The film thickness (d, mm) of the microporous film was determined by measuring the film thickness with a contact-type film thickness meter at 30 points of the microporous film, and taking the average value. The porosity (V,%) was calculated by measuring the weight (W, g) of a 10 cm × 10 cm microporous membrane, and calculating the true density (0.950 g / cm ³ ) of the porous membrane as shown below (e).

V = 100-W / 0.095d (e)
~ Measurement of tensile strength at break ~
A sample cut out from a stretched microporous membrane and an ultrahigh molecular weight polyethylene evaluation sheet into a dumbbell shape (measurement width 5 mm) was allowed to stand at 23 ° C. for 48 hours, and then a tensile tester (A & D Co., Ltd.). A tensile test was performed by a tensile test at a measurement temperature of 23 ° C., an initial length of the test piece of 20 mm, and a tensile speed of 20 mm / min, by Dee, (trade name) Tensilon RTG-1210).

-Measurement of breaking stress during melt drawing-
A sample cut into a dumbbell shape by the method described in the above measurement of tensile strength at break (10 mm in width of measurement part) was allowed to stand at 23 ° C. for 48 hours, and then a tensile tester (manufactured by A & D Co., Ltd.). , (Trade name) Tensilon UMT2.5T), a tensile test was performed at 150 ° C. with an initial length of the test piece of 10 mm and a tensile speed of 20 mm / min, and the breaking stress at the time of melt drawing was determined. When strain hardening occurs and stress increases with stretching, the maximum value is the breaking stress, and when strain hardening does not occur and stress does not increase after stretching, the stress in the flat region after yielding is the breaking stress. did.

Production Example 1
(1) Preparation of solid catalyst component In a 1 liter glass flask equipped with a thermometer and a reflux tube, 50 g (2.1 mol) of metal magnesium powder and 210 g (0.62 mol) of titanium tetrabutoxide were added. Then, 320 g (4.3 mol) of n-butanol in which 0.5 g was dissolved was added at 90 ° C. over 2 hours, and the mixture was further stirred at 140 ° C. for 2 hours under a nitrogen seal while excluding generated hydrogen gas to obtain a homogeneous solution. . Then 2100 ml of hexane was added.

  90 g of this component (equivalent to 0.095 mol of magnesium) was put in a separately prepared 500 ml glass flask and diluted with 59 ml of hexane. A hexane solution (106 ml) containing isobutylaluminum dichloride (0.29 mol) at 45 ° C. was added dropwise over 2 hours and further stirred at 70 ° C. for 1 hour to obtain a solid catalyst component. The remaining unreacted substances and by-products were removed by a gradient method using hexane, and the composition was analyzed. The titanium content was 8.6 wt%.

(2) Production of ultra high molecular weight polyethylene (A) 1.2 liters of hexane, 1.0 ml of 20% triisobutylaluminum in a 2 liter autoclave, and 4.2 mg of the solid catalyst component obtained in (1) were added. A system catalyst was prepared, and after raising the temperature to 75 ° C., ethylene was continuously supplied so that the partial pressure became 0.6 MPa. After 90 minutes, the pressure was released, and the slurry was filtered and dried to obtain 180 g of ultrahigh molecular weight polyethylene (referred to as ultrahigh molecular weight polyethylene (A-1)) (activity: 35000 g / g catalyst). Table 1 shows the physical properties of the obtained ultrahigh molecular weight polyethylene (A-1).

Production Example 2
(1) Preparation of solid catalyst component The same procedure as in Production Example 1 was performed.

(2) Production of ultra high molecular weight polyethylene (A) 1.2 liters of hexane, 1.0 ml of 20% triisobutylaluminum in a 2 liter autoclave, and 4.2 mg of the solid catalyst component obtained in (1) were added. A system catalyst was prepared, brought to 85 ° C., hydrogen was added so that the partial pressure became 0.02 MPa, and then ethylene was continuously supplied so that the partial pressure became 0.6 MPa. The pressure was released after 90 minutes, and the slurry was filtered and dried to obtain 202 g of ultrahigh molecular weight polyethylene (hereinafter referred to as ultrahigh molecular weight polyethylene (A-2)) (activity: 48000 g / g catalyst). . Table 1 shows the physical properties of the obtained ultrahigh molecular weight polyethylene (A-2).

Production Example 3
(1) Preparation of organically modified clay Into a 1 liter flask, 300 ml of industrial alcohol (manufactured by Nippon Alcohol Sales Co., Ltd., (trade name) Echinen F-3) and 300 ml of distilled water were added, 15.0 g of concentrated hydrochloric acid and dioleylmethylamine (Lion Co., Ltd., (trade name) Armin M20) 64.2 g (120 mmol) was added and heated to 45 ° C. to disperse 100 g of synthetic hectorite (Rockwood Additives, (trade name) Laponite RDS). After that, the temperature was raised to 60 ° C. and stirred for 1 hour while maintaining the temperature. The slurry was separated by filtration, washed twice with 600 ml of water at 60 ° C., and dried in an oven at 85 ° C. for 12 hours to obtain 160 g of organically modified clay. This organically modified clay was pulverized by a jet mill to have a median diameter of 7 μm.

(2) Preparation of metallocene polyethylene catalyst suspension Suspension of 300 ml flask equipped with thermometer and reflux tube was replaced with nitrogen, and 25.0 g of organically modified clay obtained in (1) and 108 ml of hexane were added. Then, 0.795 g of diphenylmethylene (4-phenyl-1-indenyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride and 142 ml of 20% triisobutylaluminum were added at 60 ° C. for 3 hours. Stir for hours. After cooling to 45 ° C., the supernatant was extracted, washed twice with 200 ml of hexane, and then 200 ml of hexane was added to obtain a suspension of the catalyst for producing metallocene polyethylene (solid weight: 11.7 wt%).

(3) Production of ultrahigh molecular weight polyethylene (B) 1.2 liters of hexane and 1.0 ml of 20% triisobutylaluminum in a 2 liter autoclave, suspension of the metallocene polyethylene production catalyst obtained in (2) After adding 356 mg of liquid (equivalent to 41.7 mg of solid content) to 45 ° C., ethylene was continuously supplied so that the partial pressure was 2.2 MPa, and slurry polymerization of ethylene was performed. After 180 minutes, the pressure was released, and the slurry was filtered and dried to obtain 52.1 g of ultrahigh molecular weight polyethylene (hereinafter referred to as ultrahigh molecular weight polyethylene (B-1)) (activity: 1250 g / g). catalyst). Table 1 shows the physical properties of the obtained ultrahigh molecular weight polyethylene (B-1).

Production Example 4
(1) Preparation of organically modified clay and (2) Preparation of suspension of catalyst for metallocene polyethylene production The same procedure as in Production Example 3 was performed.

(3) Production of ultrahigh molecular weight polyethylene (B) 1.2 liters of hexane and 1.0 ml of 20% triisobutylaluminum in a 2 liter autoclave, suspension of the metallocene polyethylene production catalyst obtained in (2) 38.6 mg of liquid (corresponding to solid content of 38.2 mg) was added and the temperature was adjusted to 30 ° C., then 3.5 g of propylene was added, and ethylene was continuously supplied so that the partial pressure became 2.0 MPa, and slurry polymerization was performed. It was. After 180 minutes, the pressure was released, and the slurry was filtered and dried to obtain 42.1 g of ultra high molecular weight polyethylene (hereinafter referred to as ultra high molecular weight polyethylene (B-2)) (activity: 1090 g / g). catalyst). Table 1 shows the physical properties of the obtained ultrahigh molecular weight polyethylene (B-2).

Production Example 5
(1) Preparation of organically modified clay The same procedure as in Production Example 3 was performed.

(2) Preparation of metallocene polyethylene catalyst suspension Suspension of 300 ml flask equipped with thermometer and reflux tube was replaced with nitrogen, and 25.0 g of organically modified clay obtained in (1) and 108 ml of hexane were added. Then, 0.600 g of diphenylmethylene (cyclopentadienyl) (2- (dimethylamino) -9-fluorenyl) zirconium dichloride and 142 ml of 20% triisobutylaluminum were added and stirred at 60 ° C. for 3 hours. After cooling to 45 ° C., the supernatant was extracted, washed twice with 200 ml of hexane, and then 200 ml of hexane was added to obtain a suspension of the catalyst for producing metallocene polyethylene (solid weight: 11.5 wt%).

(3) Production of ultrahigh molecular weight polyethylene (B) 1.2 liters of hexane and 1.0 ml of 20% triisobutylaluminum in a 2 liter autoclave, suspension of the metallocene polyethylene production catalyst obtained in (2) 124 mg of liquid (corresponding to solid content of 14.2 mg) was added, the temperature was raised to 45 ° C., 2.5 g of 1-butene was added, and ethylene was continuously supplied so that the partial pressure became 1.1 MPa to perform slurry polymerization. It was. After 180 minutes, the pressure was released, the slurry was filtered, and dried to obtain 64.1 g of ultrahigh molecular weight polyethylene (denoted as ultrahigh molecular weight polyethylene (B-3)) (activity: 4500 g / g catalyst). . Table 1 shows the physical properties of the obtained ultrahigh molecular weight polyethylene (B-3).

Production Example 6
(1) Preparation of organically modified clay Into a 1 liter flask was placed 300 ml of industrial alcohol (manufactured by Nippon Alcohol Sales, (trade name) Echinen F-3) and 300 ml of distilled water, 15.0 g of concentrated hydrochloric acid and dimethylbehenylamine (Lion After adding 42.4 g (120 mmol) of (trade name) Armin DM22D manufactured by Co., Ltd. and heating to 45 ° C., 100 g of synthetic hectorite (Rockwood Additives, (trade name) Laponite RDS) was dispersed. The mixture was heated to 60 ° C. and stirred for 1 hour while maintaining the temperature. The slurry was separated by filtration, washed twice with 600 ml of 60 ° C. water, and dried in an oven at 85 ° C. for 12 hours to obtain 125 g of an organically modified clay. This organically modified clay was pulverized by a jet mill to have a median diameter of 7 μm.

(2) Preparation of metallocene polyethylene catalyst suspension Suspension of 300 ml flask equipped with thermometer and reflux tube was replaced with nitrogen, and 25.0 g of organically modified clay obtained in (1) and 108 ml of hexane were added. Then, 0.715 g of diphenylmethylene (cyclopentadienyl) (2- (diethylamino) -9-fluorenyl) hafnium dichloride and 142 ml of 20% triisobutylaluminum were added and stirred at 60 ° C. for 3 hours. After cooling to 45 ° C., the supernatant was extracted, washed twice with 200 ml of hexane, and then 200 ml of hexane was added to obtain a suspension of the catalyst for producing metallocene polyethylene (solid weight: 12.9 wt%).

(3) Production of ultrahigh molecular weight polyethylene (B) 1.2 liters of hexane and 1.0 ml of 20% triisobutylaluminum in a 2 liter autoclave, suspension of the metallocene polyethylene production catalyst obtained in (2) 127 mg (equivalent to 15.8 mg solid content) of the liquid was added, and after raising the temperature to 67 ° C., ethylene was continuously supplied so that the partial pressure became 1.3 MPa, and ethylene slurry polymerization was performed. After 180 minutes, the pressure was released, the slurry was filtered, and dried to obtain 115 g of ultrahigh molecular weight polyethylene (hereinafter, ultrahigh molecular weight polyethylene (B-4) (activity: 7300 g / g catalyst). Table 1 shows the physical properties of the ultrahigh molecular weight polyethylene (B-4).

Production Example 7
(1) Preparation of organically modified clay and (2) Preparation of suspension of catalyst for metallocene polyethylene production The same procedure as in Production Example 6 was performed.

(3) Production of ultrahigh molecular weight polyethylene (B) 1.2 liters of hexane and 1.0 ml of 20% triisobutylaluminum in a 2 liter autoclave, suspension of the metallocene polyethylene production catalyst obtained in (2) 87.7 mg of liquid (corresponding to 11.3 mg of solid content) was added, and after raising the temperature to 70 ° C., a hydrogen / ethylene mixed gas containing 22 ppm of hydrogen was supplied so that the partial pressure became 1.2 MPa. Ethylene was continuously supplied so that the pressure became 1.3 MPa, and ethylene slurry polymerization was performed. After 180 minutes, the pressure was released, and the slurry was filtered and dried to obtain 101 g of ultra high molecular weight polyethylene (hereinafter referred to as ultra high molecular weight polyethylene (B-5)) (activity: 8900 g / g catalyst). . Table 1 shows the physical properties of the obtained ultrahigh molecular weight polyethylene (B-5).

実施例１
攪拌翼を取り付けた５００ｍｌフラスコに、製造例１で製造した超高分子量ポリエチレン（Ａ−１）を１０ｇ、製造例３で製造した超高分子量ポリエチレン（Ｂ−１）を４ｇ（超高分子量ポリエチレン（Ａ−１）１００重量部に対して超高分子量ポリエチレン（Ｂ−１）４０重量部に相当）、流動パラフィンを５６ｇ、さらに酸化防止剤として、（商品名）Ｉｒｇａｎｏｘ１０１０（ＢＡＳＦ製）０．１３ｇ、（商品名）Ｉｒｇａｆｏｓ１６８（ＢＡＳＦ製）０．１３ｇを、１５０℃で１時間加熱混合し流動パラフィンを含有する超高分子量ポリエチレン組成物を調製した。

Example 1
In a 500 ml flask equipped with a stirring blade, 10 g of ultrahigh molecular weight polyethylene (A-1) produced in Production Example 1 and 4 g of ultrahigh molecular weight polyethylene (B-1) produced in Production Example 3 (ultra high molecular weight polyethylene ( A-1) 100 parts by weight of ultra high molecular weight polyethylene (B-1) equivalent to 40 parts by weight), liquid paraffin 56 g, and as an antioxidant, (trade name) Irganox 1010 (manufactured by BASF) 0.13 g, (Product Name) Irgafos 168 (manufactured by BASF) 0.13 g was heated and mixed at 150 ° C. for 1 hour to prepare an ultrahigh molecular weight polyethylene composition containing liquid paraffin.

  An ultrahigh molecular weight polyethylene composition containing liquid paraffin was mixed with a 100 cc batch kneader (trade name: Labo Plast Mill 4C150, manufactured by Toyo Seiki Seisakusho Co., Ltd.) at a kneading temperature of 190 ° C. and a rotation speed of 50 rpm for 10 minutes. After kneading, compression molding was performed to obtain a press sheet having a thickness of 0.8 mm. The press sheet was simultaneously biaxially stretched at 115 ° C. so that the set stretching ratio was 5 × 5 times in the longitudinal direction × lateral direction, then washed with hexane, liquid paraffin was removed, dried and ultrahigh molecular weight A stretched microporous membrane made of a polyethylene composition was produced.

  The obtained stretched microporous membrane made of an ultrahigh molecular weight polyethylene composition had no holes or tears that could be confirmed with the naked eye, and the surface was smooth. Moreover, the micropore was observed in the electron microscope. Table 2 shows the film thickness, porosity, breaking stress at the time of melt drawing, tensile strength, and tensile breaking elongation of the stretched microporous membrane made of this ultrahigh molecular weight polyethylene composition.

Comparative Example 1
In a 500 ml flask equipped with a stirring blade, 14 g of the ultrahigh molecular weight polyethylene (A-1) obtained in Production Example 1, 56 g of liquid paraffin, and an antioxidant (trade name) Irganox 1010 (manufactured by BASF) 0. 13 g and (trade name) Irgafos 168 (manufactured by BASF) 0.13 g were heated and mixed at 150 ° C. for 1 hour.

  The resulting mixture was kneaded for 10 minutes at a kneading temperature of 190 ° C. and a rotation speed of 50 rpm with a 100 cc batch kneader (trade name: Laboplast Mill 4C150, manufactured by Toyo Seiki Seisakusho Co., Ltd.), and then compression molded. A press sheet having a thickness of 0.8 mm was obtained. The press sheet was simultaneously biaxially stretched at 115 ° C. so that the set stretching ratio was 5 × 5 times in the longitudinal direction × lateral direction, then washed with hexane to remove liquid paraffin, and dried to obtain a microporous membrane. Manufactured.

  The obtained microporous membrane had no holes or tears that could be confirmed with the naked eye, and the surface was smooth. Moreover, the micropore was observed in the electron microscope. Table 3 shows the film thickness, porosity, fracture stress during melt stretching, tensile strength, and tensile elongation at break of this microporous membrane. It was inferior to the breaking stress and tensile strength at the time of melt drawing.

Comparative Example 2
In a 500 ml flask equipped with a stirring blade, 14 g of ultrahigh molecular weight polyethylene (B-1) obtained in Production Example 3, 56 g of liquid paraffin, and (trade name) Irganox 1010 (manufactured by BASF) 0. 13 g and (trade name) Irgafos 168 (manufactured by BASF) 0.13 g were heated and mixed at 150 ° C. for 1 hour. The resulting mixture was kneaded for 10 minutes at a kneading temperature of 190 ° C. and a rotation speed of 50 rpm with a 100 cc batch kneader (trade name: Laboplast Mill 4C150, manufactured by Toyo Seiki Seisakusho Co., Ltd.), and then compression molded. A press sheet having a thickness of 0.8 mm was obtained.

  The press sheet is simultaneously biaxially stretched at 115 ° C. so that the set stretching ratio is 5 × 5 times in the longitudinal direction × lateral direction, washed with hexane, liquid paraffin is removed and dried to form a microporous membrane. Manufactured.

  The obtained microporous membrane had no holes or tears that could be confirmed with the naked eye, and the surface was somewhat rough. Moreover, the micropore was observed in the electron microscope. Table 3 shows the film thickness, porosity, fracture stress during melt stretching, tensile strength, and tensile elongation at break of this microporous membrane. The tensile elongation at break was inferior.

Example 2
Instead of 10 g of ultra high molecular weight polyethylene (A-1), 7 g of commercially available ultra high molecular weight polyethylene (trade name) Hi-Z Million 240M (Mitsui Chemicals) (hereinafter referred to as ultra high molecular weight polyethylene (A-3)), Instead of 4 g of ultra high molecular weight polyethylene (B-1), 7 g of ultra high molecular weight polyethylene (B-1) (100 parts by weight of ultra high molecular weight polyethylene (A-3) is ultra high molecular weight polyethylene (B-1) 100. A stretched microporous membrane made of an ultra-high molecular weight polyethylene composition was produced in the same manner as in Example 1 except that (corresponding to parts by weight) was used.

  The obtained stretched microporous membrane made of an ultrahigh molecular weight polyethylene composition had no holes or tears that could be confirmed with the naked eye, and had a smooth surface. Moreover, the micropore was observed in the electron microscope. Table 2 shows the film thickness, porosity, breaking stress at the time of melt drawing, tensile strength, and tensile breaking elongation of the stretched microporous membrane made of this ultrahigh molecular weight polyethylene composition.

Example 3
Instead of 10 g of ultrahigh molecular weight polyethylene (A-1), 3.5 g of ultrahigh molecular weight polyethylene (A-1) and 10 g of ultrahigh molecular weight polyethylene (B-2) instead of 4 g of ultrahigh molecular weight polyethylene (B-1) 0.5 g (corresponding to 300 parts by weight of ultrahigh molecular weight polyethylene (B-2) per 100 parts by weight of ultrahigh molecular weight polyethylene (A-1)) was used in the same manner as in Example 1 to obtain an ultrahigh molecular weight. A stretched microporous membrane made of a polyethylene composition was produced.

  The obtained stretched microporous membrane made of an ultrahigh molecular weight polyethylene composition had no holes or tears that could be confirmed with the naked eye, and had a smooth surface. Moreover, the micropore was observed in the electron microscope. Table 2 shows the film thickness, porosity, breaking stress at the time of melt drawing, tensile strength, and tensile breaking elongation of the stretched microporous membrane made of this ultrahigh molecular weight polyethylene composition.

Comparative Example 3
Instead of 10 g of ultrahigh molecular weight polyethylene (A-1), 3.5 g of ultrahigh molecular weight polyethylene (A-1) is used, and instead of 4 g of ultrahigh molecular weight polyethylene (B-1), commercially available ultrahigh molecular weight polyethylene (trade name) ) Hi-X Million 340M (Mitsui Chemicals) (hereinafter referred to as "ultra high molecular weight polyethylene (A-4)"), except that the amount was 10.5 g. A microporous membrane was produced.

  The obtained microporous membrane had no holes or tears that could be confirmed with the naked eye, and the surface was smooth. Moreover, the micropore was observed in the electron microscope. Table 3 shows the film thickness, porosity, fracture stress during melt stretching, tensile strength, and tensile elongation at break of this microporous membrane. It was inferior to the breaking stress and tensile strength at the time of melt drawing.

Example 4
Instead of 10 g of ultra high molecular weight polyethylene (A-1), 8 g of ultra high molecular weight polyethylene (A-4) is used, and instead of 4 g of ultra high molecular weight polyethylene (B-1), ultra high molecular weight polyethylene (B-3) is used. Ultra high molecular weight polyethylene composition by the same method as in Example 1 except that 6 g (corresponding to 75 parts by weight of ultra high molecular weight polyethylene (B-3) per 100 parts by weight of ultra high molecular weight polyethylene (A-4)) was used. A product stretched microporous membrane was produced.

  The obtained stretched microporous membrane made of an ultrahigh molecular weight polyethylene composition had no holes or tears that could be confirmed with the naked eye, and had a smooth surface. Moreover, the micropore was observed in the electron microscope. Table 2 shows the film thickness, porosity, breaking stress at the time of melt drawing, tensile strength, and tensile breaking elongation of the stretched microporous membrane made of this ultrahigh molecular weight polyethylene composition.

Example 5
Instead of 10 g of ultrahigh molecular weight polyethylene (A-1), 12 g of ultrahigh molecular weight polyethylene (A-2) is used, and instead of 4 g of ultrahigh molecular weight polyethylene (B-1), ultrahigh molecular weight polyethylene (B-4) is used. The composition of the ultrahigh molecular weight polyethylene was the same as in Example 1 except that the amount was 2 g (equivalent to 17 parts by weight of the ultrahigh molecular weight polyethylene (B-4) per 100 parts by weight of the ultrahigh molecular weight polyethylene (A-2)). A product stretched microporous membrane was produced.

  The obtained stretched microporous membrane made of an ultrahigh molecular weight polyethylene composition had no holes or tears that could be confirmed with the naked eye, and had a smooth surface. Moreover, the micropore was observed in the electron microscope. Table 2 shows the film thickness, porosity, breaking stress at the time of melt drawing, tensile strength, and tensile breaking elongation of the stretched microporous membrane made of this ultrahigh molecular weight polyethylene composition.

Comparative Example 4
Instead of 10 g of ultra high molecular weight polyethylene (A-1), 12 g of ultra high molecular weight polyethylene (B-2) is used, and instead of 4 g of ultra high molecular weight polyethylene (B-1), ultra high molecular weight polyethylene (B-4) is used. A microporous membrane was produced in the same manner as in Example 1 except that the amount was 2 g.

  The obtained microporous membrane had no holes or tears that could be confirmed with the naked eye, but the surface was somewhat rough. Moreover, the micropore was observed in the electron microscope. Table 3 shows the film thickness, porosity, fracture stress during melt stretching, tensile strength, and tensile elongation at break of this microporous membrane. The tensile elongation at break was inferior.

Example 6
Instead of 10 g of ultra high molecular weight polyethylene (A-1), 10.5 g of ultra high molecular weight polyethylene (A-2) is used, and ultra high molecular weight polyethylene (B-5) is used instead of 4 g of ultra high molecular weight polyethylene (B-1). ) By 3.5 g (equivalent to 33 parts by weight of ultrahigh molecular weight polyethylene (B-5) per 100 parts by weight of ultrahigh molecular weight polyethylene (A-2)). A stretched microporous membrane made of a high molecular weight polyethylene composition was produced.

  The obtained stretched microporous membrane made of an ultrahigh molecular weight polyethylene composition had no holes or tears that could be confirmed with the naked eye, and had a smooth surface. Moreover, the micropore was observed in the electron microscope. Table 2 shows the film thickness, porosity, breaking stress at the time of melt drawing, tensile strength, and tensile breaking elongation of the stretched microporous membrane made of this ultrahigh molecular weight polyethylene composition.

  The stretched microporous membrane made of ultra high molecular weight polyethylene composition obtained by the present invention is excellent in strength and heat resistance, and can be used for various applications such as gas separation membranes, gas permeable membranes, tapes, tubes, and battery separators. is there.

Claims (7)

100 wt. Of ultra high molecular weight polyethylene (A) having an intrinsic viscosity of 7 dl / g or more and 35 dl / g or less measured under the following measurement conditions (1) and a stress at break (MTS) of 1 MPa or less when melt stretched at 150 ° C. Part of the ultrahigh molecular weight polyethylene (B) 5 having an intrinsic viscosity of 15 dl / g or more and 60 dl / g or less measured at the following measurement condition (1) and a stress at break when melt stretched at 150 ° C. of 2 MPa or more. A stretched microporous membrane made of an ultrahigh molecular weight polyethylene composition, comprising an ultrahigh molecular weight polyethylene composition containing at least 900 parts by weight.
Measurement condition (1): Measured with an Ubbelohde viscometer using orthodichlorobenzene as a solvent at 135 ° C. with an ultrahigh molecular weight polyethylene concentration of 0.005 wt%. The ultrahigh molecular weight polyethylene (A) is obtained by homopolymerization or copolymerization of ethylene in the presence of a Ziegler catalyst or a Philips catalyst. Stretched microporous membrane. Melting point (Tm) of 1st scan when ultrahigh molecular weight polyethylene (B) was heated from a temperature of 0 ° C. to 230 ° C. (1st scan) with a differential scanning calorimeter (DSC). ₁ ) After that, after being left for 5 minutes, the temperature was lowered to −20 ° C. at a temperature lowering rate of 10 ° C./min. After being left for 5 minutes, the temperature was raised again from −20 ° C. to 230 ° C. at a temperature raising rate of 10 ° C./min The melting point (Tm ₂ ) of 2nd scan at the time of (2nd scan) is measured, and the difference between ΔTm ₁ and Tm ₂ (ΔTm = Tm ₁ −Tm ₂ ) satisfies 11 ° C. or more and 30 ° C. or less. The stretched microporous membrane made of an ultrahigh molecular weight polyethylene composition according to claim 1 or 2, wherein The ultrahigh molecular weight polyethylene (B) is characterized in that the stress at break (MTS) and intrinsic viscosity ([η]) when melt-drawn at 150 ° C. also satisfy the following relational expression (a): A stretched microporous membrane made of the ultrahigh molecular weight polyethylene composition according to claim 1.
MTS ≧ 0.11 × [η] (a) The ultrahigh molecular weight polyethylene according to any one of claims 1 to 4, wherein the ultrahigh molecular weight polyethylene (B) is obtained by homopolymerization or copolymerization of ethylene in the presence of a metallocene catalyst. A stretched microporous membrane made of the composition. The ultrahigh molecular weight polyethylene composition according to any one of claims 1 to 5 and an organic solvent are mixed at a temperature of 50 ° C to 300 ° C to form a sheet, and then biaxially stretched on the sheet. The stretched microporous membrane made of an ultrahigh molecular weight polyethylene composition according to any one of claims 1 to 5, wherein the organic solvent is removed. The ultra high molecular weight polyethylene composition according to any one of claims 1 to 6, which is any one selected from the group consisting of a gas separation membrane, a gas permeable membrane, a tape, a tube, and a battery separator. Stretched microporous membrane.