POROUS FILM OF METAPHENYLENE ISOPHTHALAMIDE-BASED POLYMER AND MANUFACTURING METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide a porous film of a metaphenylene isophthalamide-based polymer used for an electric cell separator that is excellent in MacMillan number and sticking strength, and to provide a manufacturing method therefor. SOLUTION: A dope formed by dissolving a metaphenylene isophthalamide- based polymer in an amide-based solvent is cast in the form of a film. The cast film is solidified in a 50-70% amide-based solution. After washing with water and drying, it is laminated and contacted with a hot plate to be stretched monoaxially or biaxially not less than 1.3 times and not more than 10 times to manufacture a porous film having a sticking strength of 10-25 g/μm, and a MacMillan number of 3-20 as a porous film with a thickness of 6-25μm and a porosity of 20-80%.