Abstract: A lateral surface (12e) of a long separator sheet (12a, 12b) has a value of edge length (R)/longer side length (P) which is less than 1.04. It is therefore possible to provide the long porous separator sheet that is less likely to be torn in processing.

Abstract: The application relates to a laminated porous film having a heat-resistant layer that is suitable for a separator for a non-aqueous electrolyte secondary battery having excellent cycle characteristics, and a coating liquid for forming the heat-resistant layer. A coating liquid containing a filler, a binder, and a solvent, wherein a hydrophilicity parameter A of the filler defined by formula (1) is 0.35 to 0.65: Hydrophilicity parameter A=BET1/BET2 ??(1) wherein, in formula (1), BET1: the specific surface area of the filler calculated using a BET method from a differential adsorption isotherm obtained by subtracting, from a first adsorption isotherm measured by adsorbing water vapor to the filler, a second adsorption isotherm; and BET2: the specific surface area of the filler calculated using a BET method from a differential adsorption isotherm measured by adsorbing nitrogen to the filler.

Abstract: A lateral surface (12e) of a long separator sheet (12a, 12b) has a value of edge length (R)/longer side length (P) which is less than 1.04. It is therefore possible to provide the long porous separator sheet that is less likely to be torn in processing.

Abstract: A long separator sheet (12a?, 12b?) has a right edge part (12c?) that is in a trapezoidal shape and a left edge part (12d?) having a curved shape. Therefore, it is possible to provide a long porous separator sheet which satisfies both a good electrolyte take-in property (i.e., liquid absorption property) and a good electrolyte retaining property (i.e., liquid retention property).

Abstract: Provided is a nonaqueous electrolyte secondary battery separator including a porous film containing, as a main component, polyolefin having a weight average molecular weight of not less than 500,000, the nonaqueous electrolyte secondary battery separator having an MD orientation ratio of 58% to 80%, a degree of MD orientation of 70% to 80%, and a degree of TD orientation of 65% to 85%, the nonaqueous electrolyte secondary battery separator having a film thickness of not more than 14 ?m, and the nonaqueous electrolyte secondary battery separator being excellent in shutdown temperature and puncture strength.

Abstract: A nonaqueous electrolyte secondary battery separator includes a porous film containing, as a main component, polyethylene having a weight average molecular weight of not less than 500,000, the nonaqueous electrolyte secondary battery separator having a peak area ratio R of not less than 0.90, the peak area ratio R (i) being defined by areas I(110) and I(200) of diffraction peaks on (110) and (200) planes of a crystal of the polyethylene, the diffraction peaks being detected in a case where the porous film is irradiated with an X-ray from a thickness direction of the porous film, and (ii) being represented by the following equation: R=I(110)/(I(110)+I(200)), and the nonaqueous electrolyte secondary battery separator having a film thickness of not more than 14 ?m.

Abstract: Provided is a nonaqueous electrolyte secondary battery separator including a porous film containing, as a main component, polyolefin having a weight average molecular weight of not less than 500,000, the nonaqueous electrolyte secondary battery separator having an MD orientation ratio of 58% to 80%, a degree of MD orientation of 70% to 80%, and a degree of TD orientation of 65% to 85%, the nonaqueous electrolyte secondary battery separator having a film thickness of not more than 14 ?m, and the nonaqueous electrolyte secondary battery separator being excellent in shutdown temperature and puncture strength.

Abstract: The present invention relates to a laminated porous film having a heat-resistant layer that is suitable for a separator for a non-aqueous electrolyte secondary battery having excellent cycle characteristics, and a coating liquid for forming the heat-resistant layer. A coating liquid containing a filler, a binder, and a solvent, wherein hydrophilicity parameter A of the filler defined by formula (1) is 0.35 to 0.65: Hydrophilicity parameter A=BET1/BET2??(1) wherein BET1: the specific surface area of the filler calculated using a BET method from a differential adsorption isotherm obtained by subtracting, from a first adsorption isotherm measured by adsorbing water vapor to the filler, a second adsorption isotherm; and BET2: the specific surface area of the filler calculated using a BET method from a differential adsorption isotherm measured by adsorbing nitrogen to the filler.