MULTILAYER POROUS FILM AND SEPARATOR FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

Disclosed is a multilayer porous film wherein a heat-resistant resin layer is arranged on a porous film which is formed from a polyolefin resin containing an ethylene/a-olefin copolymer composed of a structural unit derived from ethylene and another structural unit derived from one or more monomers selected from a-olefins having 4-10 carbon atoms. The multilayer porous film has a shutdown temperature of not more than 125°C and a thermal film-breaking temperature of not less than 155°C.