POROUS FILM, BATTERY SEPARATOR AND BATTERY

摘要

To provide a porous film that has excellent air permeability by improving the processing characteristics for the purpose of more successfully making a film porous by a stretching process. The present invention is a porous film which is characterized by being mainly composed of a polypropylene resin composition that has ß activity and a weight average molecular weight (Mw) as determined by a high-temperature GPC method of 100,000 or more. With respect to the polypropylene resin composition, the proportion of the common logarithm of the Mw (logMw) being 4.8 or less is 15% or more of the whole.