METHOD OF PRODUCING LAMINATED POROUS FILM, LAMINATED POROUS FILM, AND NON-AQUEOUS ELECTROLYTIC SOLUTION SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a method of producing a laminated porous film including a heat-resistant layer which is formed by applying a coating fluid including a filler to a base material porous film having different surface roughness, while further preventing fall of powder.SOLUTION: In a laminated porous film, heat-resistant layers each including an inorganic filler and a binder are laminated on both faces of a polyolefin base material porous film having different surface roughness. The method of producing the laminated porous film includes the steps of: applying a coating fluid including an inorganic filler, a binder and a solvent to the face with smaller surface roughness of the base material porous film and distilling away the solvent, to form a first heat-resistant layer; and applying the coating fluid to the face with larger surface roughness of the base material porous film in which the heat-resistant layer is formed and distilling away the solvent, to form a second heat-resistant layer.