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The present invention provides a polyolefin multilayer microporous membrane that has a low air permeability value, maintains high porosity and mechanical strength even when formed into a thin film, has excellent impedance characteristics, and has excellent battery characteristics when used as a battery separator. (Solution) A polyolefin multilayer microporous membrane including a first microporous layer and a second microporous layer; the first microporous layer including a first polyolefin resin containing a polypropylene; the second microporous layer including a second polyolefin resin containing an ultrahigh molecular weight polyethylene; and the polyolefin multilayer microporous membrane satisfying the following requirements (I) and (II).(I) A membrane thickness is not greater than 25 m, and the membrane thickness (m) and a porosity (%) satisfy the relationship in the formula below. (II) An air permeability in terms of a membrane thickness of 16 m is not less than 100 sec/100 cm^(3) and not greater than 300 sec/100 cm^(3).


A polyolefin multilayer microporous membrane is disclosed. The polyolefin multilayer microporous membrane has a low air permeability value, maintains high porosity and mechanical strength even when formed into a thin film. The polyolefin multilayer microporous membrane also has excellent impedance characteristics. The polyolefin multilayer microporous membrane has excellent battery characteristics when used as a battery separator.


A polyolefin multilayer microporous membrane is disclosed. The polyolefin multilayer microporous membrane has at least three layers, the membrane comprising a first microporous layer composed of a polyethylene resin containing an ultrahigh molecular weight polyethylene (surface layers) and a second microporous layer composed of a polyolefin rein containing a high-density polyethylene and polypropylene (intermediate layer), wherein (I) the pin puncture strength is at least 25 g/m, (II) the coefficient of static friction with respect to a metal foil is at least 0.40, and (III) the meltdown temperature is at least 180 C.


The present invention provides a polyolefin microporous membrane which has a small pore size and excellent shutdown characteristics and is suitable for use as a separator for a non-aqueous electrolyte secondary battery. The present invention provides a polyolefin microporous membrane in which the difference between the shutdown starting temperature in the MD and the maximum shrinkage temperature in the MD is not less than 8.6C, and the maximum pore size is less than 0.036 m. In addition, the present invention provides a production method for a polyolefin microporous membrane comprising melt-kneading a polyolefin resin containing an ultrahigh molecular weight polyolefin and a plasticizer, forming the mixture into a sheet shape, performing stretching in the MD and simultaneous biaxial stretching on the obtained sheet, and then drying the stretched sheet.


Patent
The Film Co | Date: 2017-03-02

A polyolefin microporous membrane includes a polyethylene composition, and 0.5% or more but less than 5% by mass of polypropylene, wherein the polyethylene composition includes polyethylene having a mass average molecular weight of 2.510^(5 )to 510^(5 )and ultrahigh molecular weight polyethylene having a mass average molecular weight of 110^(6 )to 310^(6 )in an amount of more than 5% by mass and not more than 50% by mass based on 100% by mass of polyethylene composition and has a molecular weight distribution (Mw/Mn) of 5.0 to 300, and the polyolefin microporous membrane has an injection of electrolyte of 20 seconds or less and a uniform polypropylene distribution in at least one plane perpendicular to the thickness direction.


The present invention provides a microporous membrane having an excellent balance of temperature characteristics, shrinkage characteristics, permeability, and strength, and thereby realizes a separator for a non-aqueous electrolyte secondary battery and a non-aqueous electrolyte secondary battery, having excellent performance and excellent safety. A polyolefin microporous membrane having;a temperature difference not less than 7.2C between a shutdown shrinkage temperature and a maximum shrinkage temperature in a TD measured by TMA;a shrinkage rate difference less than 25% between a shutdown shrinkage rate and a maximum shrinkage rate in the TD;a pin puncture strength at a membrane thickness of 16 m being not less than 400 gf; anda ratio of pin puncture strength to air permeation resistance at a membrane thickness of 16 m being from 2.0 to 4.0 (gf/(sec/100 cc)).


There is provided a polyethylene-based thermally-shrinkable film for pack-in box packaging, in which: a product is not damaged due to breakage or looseness of a film during packaging and transportation of the product; because of the low-temperature shrink characteristic, the product is not exposed to excessively high heat during shrink wrapping and power consumption in a shrink tunnel can be reduced; and because of a small thickness of the film, garbage and other wastes can be reduced. A polyethylene-based multilayer film, the film is a polyethylene-based thermally-shrinkable multilayer film for pack-in box packaging obtained by biaxial orientation in MD and TD and stretching in MD only further after biaxial orientation. Preferably, the film is a polyethylene-based thermally-shrinkable multilayer film for pack-in box packaging in which the film as a whole has a thickness of 25 m or less.


Patent
The Film Co | Date: 2017-08-02

The present invention aims to provide a separator for batteries that achieves both adhesiveness to electrodes and low thermal shrinkage, which have been conventionally difficult to be compatible with each other, and has excellent ion permeability in order to further improve the safety of the separator, on the assumption that lithium ion secondary batteries are widely used for electric automobiles and the like, which require the batteries to withstand severe operating conditions. The separator for batteries is configured such that a modified porous layer containing a fluororesin and inorganic particles is laminated on at least one side of a porous membrane formed of a polyolefin resin. The content of the particles is equal to or more than 40% by volume and less than 70% volume with respect to the total of the fluororesin and the particles. The fluororesin has a crystallinity of equal to or more than 36% and less than 70%.


Disclosed is an organic/inorganic composite porous film comprising: (a) inorganic particles; and (b) a binder polymer coating layer formed partially or totally on surfaces of the inorganic particles, wherein the inorganic particles are interconnected among themselves and are fixed by the binder polymer, and interstitial volumes among the inorganic particles form a micropore structure. A method for manufacturing the same film and an electrochemical device including the same film are also disclosed. An electrochemical device comprising the organic/inorganic composite porous film shows improved safety and quality.


The present invention relates to a polyolefin microporous membrane having an air permeability normalized to a thickness of 16 m of from 100 to 220 sec/100 cc, a pin puncture strength normalized to a thickness of 16 m of not less than 550 gf, and a crystallization half time t_(1/2) of from 10 to 35 minutes when subjected to isothermal crystallization at 117C; a separator for a battery using the same; and a production method thereof. The polyolefin microporous membrane of the present invention has excellent pin puncture strength and air permeability, suppresses curling, and has an excellent appearance without wrinkles or winding deviation when formed into a roll.

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