| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyolefin microporous film having excellent balance among air permeability, porosity, pore diameter, bubble point value, mechanical strength, dimensional stability, shutdown characteristics and melt down characteristics, a method for producing the polyolefin microporous film and use thereof. SOLUTION: This method for producing the polyolefin microporous film comprises using a polyolefin having 21-60 wt.% fraction (a) of >=1×10<6> weight- average molecular weight, 40-79 wt.% sum total of a fraction (b) of >=1×10<4> and <1×10<6> weight-average molecular weight and a fraction (c) of <1×10<4> weight-average molecular weight and <=30 wt.% of the fraction (c) and 7-50 of ratio Mw/Mn. |
