| 摘要 |
PROBLEM TO BE SOLVED: To provide a porous film suited for e.g. battery separators and having high facial strength and high pin piercing elongation. SOLUTION: This is a porous film made from a high-molecular weight- polyethylene resin having a viscosity-average molecular weight of 3000,000 to below 1,000,000 and having a thickness of 5-50μm, an air permeability of 250-1000 sec/100 cc, a porosity of 30-50%, a pin piercing strength of 400 gf/25μm or above and a pin piercing elongation of 2.0 mm or above, wherein the thermal shrinkage in the direction of width is 5% or below at 105 deg.C. |
