| abstract |
PROBLEM TO BE SOLVED: To provide a microporous polyethylene membrane having excellent mechanical strength, permeability and productivity, and having extremely high heat resistance so as to ensure the safety of a battery even under severe conditions. SOLUTION: A polyethylene microporous membrane having a molecular weight between crosslinking points of 200,000 or less, a residual shrinkage of 15% or more, and a porosity of 20 to 80%. |