EXTRUSION METHOD AND APPARATUS FOR MANUFACTURING MICROPOROUSFILM

摘要

A method and apparatus for producing microporous films. The method utilizes a casting surface (14) and a condensing surface (18). The condensing surface (18) is spaced from the casting surface (14) to form a gap. The distance between the surfaces forming the gap is relatively small and is preferably less than 3 cm. A material, capable of forming microporous films through thermally induced phase separation processes, is cast onto the casting surfa ce (14), preferably through conventional extrusion practices. The material contains at least one evaporative component that generally flashes off upon formation of the microporous material and condenses on the condensing surfac e (14).