POROUS POLYOLEFIN RESIN FILM AND SEPARATOR FOR BATTERY

摘要

Disclosed is a porous polyolefin resin film which has high intercommunicating properties and excellent dimensional stability, while fulfilling such a shutdown function that the pores are not closed up at temperatures less than 120°C but are sensitively and completely closed up within the temperature range of 120-140°C. Specifically disclosed is a porous polyolefin resin film which is characterized by comprising at least one layer that is mainly composed of a polypropylene resin composition (A) and at least one layer that is mainly composed of a polyethylene resin composition (B) which satisfies the condition (i) such that the melting point of the polyethylene resin composition (B) is not less than 130°C and the condition (ii) such that the melt flow rate (MFR) of the polyethylene resin composition (B) is 2.0-15 g/10 min.