| 摘要 |
A polyethylene microporous membrane for a separator of a secondary battery is provided to realize improved physical properties, including a porosity of 30-90% and high impact strength and tensile strength. A polyethylene microporous membrane for a separator of a secondary battery is obtained by melt kneading and extruding a starting material composition containing a polyethylene resin and a solvent, followed by cooling to form a gel-like composition, biaxially orienting the gel-like composition, extracting the remaining solvent, and hot fixing the resultant product. The polyethylene resin has a weight average molecular weight(Mw) of 300000-700000, and a ratio of the weight average molecular weight(Mw)/number average molecular weight(Mn) of 10-20, and comprises a fraction with a molecular weight of 1000000 or higher in a ratio of 5-35%. |
