PURPOSE: To obtain the titled film outstanding in air and moisture permeability, water resistance, etc., by blending a polyolefin resin and saturated fatty acid metal salt-treated filler in specified proportion and melt forming into a sheet or film which is then drawn.
CONSTITUTION: A blend made up of (A) 30W70(pref. 30W60)wt.% of a polyolefin resin [pref. a propylene (co)polymer with an intrinsic viscosity of 2.0W3.0dl/g] and (B) 70W30(pref. 70W40)wt.% of filler (pref. calcium oxide or silicone resin with an average size of 0.01W0.5μ) surface-treated with a saturated fatty acid metal salt (pref. aluminum stearate) is subjected to melt forming into a sheet or film, which is then drawn, thus obtaining the objective fine porous film suitable for the separators used in batteries. In order to enhance the formability, it is suggested that said blend be incorporated with a nonionic surfactant such as polyoxyethylene alkylphenyl ether.
KAMURA MITSUO
UMEDA HIROYUKI
NAKANO HIDEKI
| JPS6295216A | 1987-05-01 | |||
| JPS5142617A | 1976-04-10 |