| 摘要 |
PURPOSE:To obtain the subject film having excellent slipperiness, uniformly roughened into the surface of a wooden skin structure and useful for high density magnetic recording media, etc., by forming a self-supporting film from a film-forming solution containing plural kinds of aromatic polyamic acids and subsequently stretching and heat-treating the film. CONSTITUTION:A solution for forming films is produced by homogeneously dissolving (A) the first aromatic polyamic acid obtained from (i) an aromatic tetracarboxylic acid component and (ii) an aromatic diamine component consisting of an aromatic diamine compound having a benzene ring, (B) the second aromatic polyamic acid obtained from the component (i) and an aromatic diamine component consisting of an aromatic diamine compound having >=2 benzene rings and (C) an imidating agent in an organic polar solvent. The produced solution is formed into a film on a support and dried at <=200 deg.C to provide a self-supporting film, which is stretched by 1.1-1.3 times at <=100 deg.C and heat-treated at 150 deg.C. |
