Process of producing porous thermoplastic resin article

摘要

A process of producing a porous thermoplastic resin article in the form of hollow yarn or film which comprises a step for forming a large number of micropores in the article by drawing an article, which is characterized in that the drawing process is performed in a medium selected from the group consisting of nitrogen, oxygen, argon, carbon monoxide and a hydrocarbon such as methane or ethane at a temperature in the range of the freezing point to 50 DEG C. above the boiling point of said medium.