Patent ID: 7141168
Filing Date: 2006-11-28
Classification: B01D,H01M,Y02E,Y10T

Abstract:
1. A porous polyolefin membrane formed by melting and kneading a resin composition containing a polyolefin resin (C) consisting of 30–90 wt % crystalline polypropylene (A) and 10–70 wt % propylene-α-olefin copolymer (B), dispersed in said crystalline polypropylene (A), wherein a ratio of the melt flow rate of said crystalline polypropylene (A) MFR pp to that of said propylene-α-olefin copolymer (B) MFR RC is between 0.1 and 10, to obtain a film-shaped melt, and forming a membrane from said melt at a draft ratio range being from 1 to 10, followed by stretching said membrane at least in one direction, which contains continuous pores in the region consisting of said copolymer (B).