Production of porous film having excellent air permeability

Abstract

Abstract PURPOSE:To obtain a porous film having excellent air permeability and various uses as permeable packaging materials, separating-filtering membranes, etc., by melt-kneading two kinds of thermoplastic resins having different melting points and poor compatibility with each other, molding the mixture into a film followed by stretching. CONSTITUTION:A thermoplastic resin A such as polypropylene having a m.p. of 160 deg.C is melt-kneaded with a thermoplastic resin B having poor compatibility with a resin A and a m.p. which is at least 20 deg.C higher than that of the resin A, such as a polycarbonate having a m.p. of 245 deg.C. The mixture is molded to a temp. higher than the m.p. of the resin A but lower than the m.p. of the resin B into a sheet which is then stretched at least monoaxially to obtain the titled porous film.

Inventors

• 👤 Akira Nishio
• 👤 章 西尾
• 👤 Yoshikatsu Maruyama
• 👤 丸山　美勝

Bibliographic Details