POLYOLEFIN MICROPOROUS MEMBRANE, PRODUCTION METHOD THEREFOR, AND BATTERY SEPARATOR

摘要

Provided are a polyolefin microporous membrane and a battery separator, the polyolefin microporous membrane being characterized by the following: containing at least 90 mass% of polypropylene resin; having tensile strength in the MD direction of at least 25MPa; having tensile strength in the TD direction of at least 25MPa; the tensile strength ratio between the MD direction and the TD direction being 0.4-2.0 inclusive; having tensile elongation in the MD-direction of at least 80%; and the tensile elongation ratio between the MD direction and the TD direction being 0.6-1.7 inclusive. Such polyolefin microporous membrane has excellent oxidation resistance, an excellent meltdown temperature, and toughness.