Verfahren zur Herstellung von mikroporösen Membranen aus Polyolefin

摘要

An efficient method of producing a microporous polyolefin membrane having improved tensile strength and pierce strength is provided, in which a solution having dissolved therein 5% by weight to 50% by weight of a polyolefin whose weight-average molecular weight is in the range of 5 x 10<5> to 2.5 x 10<6> and whose weight-average molecular weight to number-average molecular weight ratio is less than 10, is extruded and rapidly cooled to obtain a gel-like product which is then stretched and has remaining solvent removed therefrom.