POLYOLEFIN MICROPOROUS FILM, SEPARATOR FOR NONAQUEOUS SECONDARY BATTERY, AND NONAQUEOUS SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a polyolefin microporous film which shows superior process permeability when it is compounded with a heat-resistant porous layer and is able to prevent drying of an electrolytic liquid.SOLUTION: In the polyolefin microporous film, when the tensile modulus of elasticity in a machine direction and in a machine vertical direction are set to Eand E, respectively, Eis 75-200 N; and E/Eis 1.3-3.0; and the bending resistance is set at 0.010-0.060 (mN cm).