POLYETHYLENE FINE POROUS MEMBRANE

摘要

PROBLEM TO BE SOLVED: To provide battery separator polyethylene fine porous membranes excellent in permeation performance and mechanical strengths and capable of terminating reaction by quick shutdown at a preferred temperature without adversely affecting battery properties at a service temperature. SOLUTION: A desired polyethylene fine porous membrane is made of a polyolefin composition comprising 20-98 wt.% polyethylene having a weight average molecular weight of 5×10<5> or more or polyethylene composition thereof and 2-80 wt.% substantially straight chain ethylene/α-olefin copolymer having a melting point of 95-125 deg.C prepared by using a single site catalyst.