COMPOSITE POROUS FILM HAVING EXCELLENT HEAT RESISTANCE

摘要

To provide a composite porous film in which thermal shrinkage is satisfactorily suppressed even when temperature exceeds a melting temperature of a polyolefin resin, adhesion between a microporous membrane and a heat-resistant layer is improved, and dropout of an inorganic filler is suppressed. The composite porous film is composed of the heat-resistant layer formed of the inorganic filler and a binder, and the microporous membrane formed of the polyolefin resin, and the composite porous film having a primary particle size of the inorganic filler in the range of 5 nanometers to 100 nanometers.