POROUS FILM

摘要

PROBLEM TO BE SOLVED: To prepare a porous film which is excellent in gas permeability and ion permeability, has high strength and can be suitably used for application such as a battery separator. SOLUTION: This porous film is characterized in that it is obtained by biaxially stretching a sheet formed from a melted and kneaded resin composition consisting of a high-density polyethylene resin, a filler and a low-molecular- weight compound at least 3-fold both longitudinally and transversely and that it has a breaking strength of 200 kg/cm or higher in each stretching direction.