Patent ID: 10147923

Abstract:
Provided is a laminated porous film suitable as a non-aqueous electrolyte secondary battery separator, which includes a heat resistant layer excellent in morphological stability at a high temperature and ion permeability and more resistant to fall-off of a filler. A laminated porous film in which a heat resistant layer including a binder resin and a filler and a base porous film including a polyolefin as a principal component are laminated, wherein the filler included in the heat resistant layer substantially consists of an inorganic filler (a) having a primary particle diameter of 0.2 to 1 μm and an inorganic filler (b) having a primary particle diameter of 0.01 to 0.1 μm, and the particle diameter of secondary aggregates of the inorganic filler (b) is not more than 2 times the primary particle diameter of the inorganic filler (a) in the heat resistant layer.