MULTILAYER POROUS FILM AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

The present invention provides a multilayer porous film and a nonaqueous electrolyte secondary battery. The multilayer porous film is obtained by laminating a heat-resistant layer that contains a binder resin and a filler and a porous base film that is mainly composed of a polyolefin. Not less than 70% by weight of the binder resin is composed of a polymer that has an alicyclic hydrocarbon group, and the weight ratio of the filler is 20 or more when the total weight of the binder resin is taken as 1. The nonaqueous electrolyte secondary battery contains the multilayer porous film as a separator.