| 摘要 |
PROBLEM TO BE SOLVED: To obtain a rough-surfaced porous film of polyethylene resin while maintaining its planar strength and air permeability adequate as a separator for a battery. SOLUTION: This porous film is made of a high-molecular-weight polyethylene resin >=300,000 but < 3000,000 in viscosity-average molecular weight, having the following properties: thickness: 5-50μm, air permeability: 10-1,000 s/100 cc, pin stick strength: >=200 gf/25μm, and surface roughness: >=3μm in terms of maximum height (Rmax ). |
