摘要 |
PURPOSE:To obtain a polyimide film which possess regular molecular aggregation structure and is crystalline and superior in mechanical properties, by performing specific combination of a composition of polyamic acid solution, manufacturing conditions of a self-supporting film and conditions of thermal imidation. CONSTITUTION:A solvent of a polyamic acid solution of a precursor of polyimide is a mixture of an antiproton polar solvent A and nonpolar solvent B which is compatible with the antiproton polar solvent A and possesses vapor pressure of 550mm Hg or higher at 140 deg.C. Then the polyamic acid solution whose solvents A, B are composed of a ratio of 70:30-97:3 is applied onto a supporting body evenly. Then the polyamic acid is dried until a solvent content of 5-40wt.% is attained under a temperature of 140 deg.C or lower. Then a self-supporting film obtained by a process where the self-supporting film is obtained is peeled off from the supporting body. Then the same is imidated a temperature of 200 deg.C or lower by performing a temperature rise at a rate of 30 deg.C/minute or faster. |