COMPOSITE POROUS FILM HAVING EXCELLENT HEAT RESISTANCE

摘要

Provided is a composite porous film in which thermal shrinkage is satisfactorily suppressed even at temperatures that exceed the melting temperature of a polyolefin resin, adhesion between a microporous film and a heat-resistant layer is improved, and dropout of an inorganic filler is suppressed. The composite porous film is constituted from a heat-resistant layer, which consists of an inorganic filler and a binder, and a microporous film consisting of a polyolefin resin. The primary particle diameter of the inorganic filler is 5-100 nm.