Abstract: A battery separator which is a laminated polyolefin microporous membrane, comprising a polyolefin microporous membrane, and a modifying porous layer comprising a water-soluble resin or water-dispersible resin, and fine particles, the modifying porous layer being laminated on at least one surface of the polyolefin microporous membrane, wherein the polyolefin microporous membrane comprises a polyethylene resin and has (a) a shutdown temperature (a temperature at which an air resistance measured while heating the polyolefin microporous membrane at a temperature rise rate of 5° C./min reaches 1×105 sec/100 cc) of 135° C. or lower, (b) a rate of air resistance change (a gradient of a curve representing dependency of the air resistance on temperature at an air resistance of 1×104 sec/100 cc) of 1×104 sec/100 cc/° C. or more, (c) a transverse shrinkage rate at 130° C. (measured by thermomechanical analysis under a load of 2 gf at a temperature rise rate of 5° C.

Abstract: A method for plasma-treating a porous body, comprising the steps of generating plasma using an inert gas or a mixed gas of an inert gas and a reactive gas, (a) blowing the resultant plasma gas to the porous body at a flow rate per a unit area of the porous body of 0.002 to 2 L/minute/cm2, (b) sucking the porous body in a plasma gas atmosphere, or (c) sucking the porous body while blowing the plasma gas to the porous body at said flow rate, thereby treating the plasma the surfaces and pores of said porous body with plasma.

Abstract: The invention relates to a method for removing diluent from a polymer extrudate, especially in connection with a process for producing a microporous membrane. The method involves contacting the extrudate with a second solvent in a first stage; contacting the extrudate from the first stage with a third solvent in a second stage; conducting a first stream away from the first stage and/or conducting a second stream away from the second stage; and cooling at least a portion of the first and/or second stream and separating therefrom at least one of a first phase rich in the second solvent or a second phase rich in the third solvent.

Abstract: A method for removing a process solvent (P-sol) from a polymer extrudate, especially in connection with a process for producing a microporous membrane. The method involves contacting the extrudate with chlorinated hydrocarbon (CHC) and hydrofluoroether (HFE) in a first stage; contacting the extrudate from the first stage with HFE in a second stage; combining the first and second waste streams and then separating the P-sol from the combined streams to make an HFE-CHC stream; cooling the HFE-CHC stream to make an HFE-rich phase and a CHC-rich phase; and conducting the CHC-rich phase and/or the HFE-rich phase to step (A).

Abstract: The invention relates to a microporous membrane. The membrane can have an average thickness of 23 ?m or more, an air permeability in a range of about 20 sec/100 cm3 to 100 sec/100 cm3, a pin puncture strength of 2,450 mN or more, and a heat shrinkage ratio of 12% or less at 105° C. The membrane can be produced from a polyolefin solution made by combining a membrane-forming solvent and at least one polyolefin resin containing polyethylene having a viscoelastic angular frequency ??0#191 of at least about 0.01 rad/sec.

Abstract: A microporous polyethylene membrane having well-balanced permeability, mechanical properties, heat shrinkage resistance, compression resistance, electrolytic solution absorbability, shutdown properties and meltdown properties, with an average pore diameter changing in a thickness direction is produced by melt-blending a polyethylene resin and a membrane-forming solvent to prepare a solution A having a resin concentration of 25 to 50% by mass and a solution B having a resin concentration of 10 to 30% by mass, the resin concentration in the solution A being higher than that in the solution B, (a) simultaneously extruding the resin solutions A and B through a die, cooling the resultant extrudate to provide a gel-like sheet in which the resin solutions A and B are laminated, and removing the membrane-forming solvent from the gel-like sheet, or (b) extruding the resin solutions A and B through separate dies, removing the membrane-forming solvent from the resultant gel-like sheets A and B to form microporous polyet

Abstract: The invention relates to a method for removing a process solvent (P-sol) from a polymer extrudate, especially in connection with a process for producing a microporous membrane. The method involves contacting the extrudate with chlorinated hydrocarbon (CHC) and hydrofluoroether (HFE) in a first stage; contacting the extrudate from the first stage with HFE in a second stage; combining the first and second waste streams and then separating the P-sol from the combined streams to make an HFE-CHC stream; cooling the HFE-CHC stream to make an HFE-rich phase and a CHC-rich phase; and conducting the CHC-rich phase and/or the HFE-rich phase to step (A).

Abstract: The invention relates to a method for removing diluent from a polymer extrudate, especially in connection with a process for producing a microporous membrane. The method involves contacting the extrudate with a second solvent in a first stage; contacting the extrudate from the first stage with a third solvent in a second stage; conducting a first stream away from the first stage and/or conducting a second stream away from the second stage; and cooling at least a portion of the first and/or second stream and separating therefrom at least one of a first phase rich in the second solvent or a second phase rich in the third solvent.

Abstract: A microporous composite membrane comprising a microporous polyolefin membrane and a polypropylene-based coating layer formed on at least one surface of the microporous polyolefin membrane, the polypropylene having a mass-average molecular weight within a range of 5,000-500,000, and solubility of 0.5 g or more in 100 g of toluene at a temperature of 25° C., and the microporous composite membrane having air permeability (converted to the value at 25-?m thickness) of 50-10,000 seconds/100 cc.

Abstract: The invention relates to a microporous membrane. The membrane can have an average thickness of 23 ?m or more, an air permeability in a range of about 20 sec/100 cm3 to 100 sec/100 cm3, a pin puncture strength of 2,450 mN or more, and a heat shrinkage ratio of 12% or less at 105° C. The membrane can be produced from a polyolefin solution made by combining a membrane-forming solvent and at least one polyolefin resin containing polyethylene having a viscoelastic angular frequency ??0#191 of at least about 0.01 rad/sec.

Abstract: A microporous polyolefin membrane comprising a polyethylene resin, and polypropylene having a weight-average molecular weight of 6×105 or more and a heat of fusion of 90 J/g or more (measured by a differential scanning calorimeter), a fraction having a molecular weight of 1.8×106 or more being 10% or more by mass of the polypropylene.

Abstract: A microporous polyolefin membrane comprising a polyethylene resin, and polypropylene having a weight-average molecular weight of 6×105 or more and a heat of fusion of 90 J/g or more (measured by a differential scanning calorimeter), a fraction having a molecular weight of 1.8×106 or more being 10% or more by mass of the polypropylene.

Abstract: A microporous polyolefin membrane comprising a polyethylene resin, and having (a) a shutdown temperature of 135° C. or lower, at which the air permeability measured while heating at a temperature-elevating speed of 5° C./minute reaches 1×105 sec/100 cm3, (b) a maximum melting shrinkage ratio of 40% or less in a transverse direction in a temperature range of 135 to 145° C., which is measured by thermomechanical analysis under a load of 2 gf and at a temperature-elevating speed of 5° C./minute, and (c) a meltdown temperature of 150° C. or higher, at which the air permeability measured while further heating after reaching the shutdown temperature becomes 1×105 sec/100 cm3 again.

Abstract: A method for plasma-treating a porous body, comprising the steps of generating plasma using an inert gas or a mixed gas of an inert gas and a reactive gas, (a) blowing the resultant plasma gas to the porous body at a flow rate per a unit area of the porous body of 0.002 to 2 L/minute/cm2, (b) sucking the porous body in a plasma gas atmosphere, or (c) sucking the porous body while blowing the plasma gas to the porous body at said flow rate, thereby treating the plasma the surfaces and pores of said porous body with plasma.

Abstract: A microporous polyethylene membrane having well-balanced permeability, mechanical properties, heat shrinkage resistance, compression resistance, electrolytic solution absorbability, shutdown properties and meltdown properties, with an average pore diameter changing in a thickness direction is produced by melt-blending a polyethylene resin and a membrane-forming solvent to prepare a solution A having a resin concentration of 25 to 50% by mass and a solution B having a resin concentration of 10 to 30% by mass, the resin concentration in the solution A being higher than that in the solution B, (a) simultaneously extruding the resin solutions A and B through a die, cooling the resultant extrudate to provide a gel-like sheet in which the resin solutions A and B are laminated, and removing the membrane-forming solvent from the gel-like sheet, or (b) extruding the resin solutions A and B through separate dies, removing the membrane-forming solvent from the resultant gel-like sheets A and B to form microporous polyet

Abstract: A hydrophilic, composite, microporous membrane having an anion exchange group and a cation exchange group on the outer surface or pore surface of a microporous, thermoplastic resin membrane substrate has excellent water permeability, mechanical strength, fine-particles-removing properties, anion-removing properties and cation-removing properties.

Abstract: A microporous polyolefin membrane made of a polyethylene resin as a main component, and having (a) a shutdown temperature of 135° C. or lower, at which the air permeability measured while heating at a temperature-elevating speed of 5° C./minute reaches 1×105 sec/100 cm3, (b) an air permeability change ratio of 1×104 sec/100 cm3/° C. or more, which is a gradient of a curve representing the dependency of the above air permeability on a temperature at the air permeability of 1×104 sec/100 cm3, and (c) a meltdown temperature of 150° C. or higher, at which the air permeability measured while further heating after reaching the above shutdown temperature becomes 1×105 sec/100 cm3 again.

Abstract: A microporous polyolefin membrane having large pore diameters and excellent air permeability, mechanical strength and compression resistance can be obtained by (a) stretching a gel molding comprising a polyolefin and a membrane-forming solvent at least uniaxially at a temperature from the crystal dispersion temperature of the polyolefin +15° C. to the crystal dispersion temperature of the polyolefin +40° C., removing the membrane-forming solvent, and then stretching again the resultant membrane to 1.1 to 2.5 fold at least uniaxially, or by (b) stretching the gel molding at least uniaxially, bringing the stretched film into contact with a hot solvent before and/or after removing the membrane-forming solvent, and then stretching again the resultant membrane to 1.1 to 2.5 fold at least uniaxially.

Abstract: A microporous polyolefin membrane comprising a polyethylene resin, and having (a) a shutdown temperature of 135° C. or lower, at which the air permeability measured while heating at a temperature-elevating speed of 5° C./minute reaches 1×105 sec/100 cm3, (b) a maximum melting shrinkage ratio of 40% or less in a transverse direction in a temperature range of 135 to 145° C., which is measured by thermomechanical analysis under a load of 2 gf and at a temperature-elevating speed of 5° C./minute, and (c) a meltdown temperature, at which the air permeability measured while further heating after reaching the above shutdown temperature becomes 1×105 sec/100 cm3 again, being 150° C. or higher.

Abstract: A microporous polyolefin membrane comprising a polyethylene resin, and polypropylene having a weight-average molecular weight of 6×105 or more and a heat of fusion of 90 J/g or more (measured by a differential scanning calorimeter), a fraction having a molecular weight of 5×104 or less being 5% or less by mass of the polypropylene.