| 摘要 |
PROBLEM TO BE SOLVED: To provide copolyimide films which equally meet a high modulus, a low coefficient of thermal expansion, a low coefficient of hygroscopic expansion and a low water absorption and further, excel in alkali etching resistance. SOLUTION: Copolyimide films are prepared from a random and/or block four-component copolyamic acid composed of 10-90 mol% 3,3',4,4'- benzophenonetetracarboxylic dianhydride and 10-90 mol% pyromellitic dianhydride on the basis of the dianhydrides, and 10-90 mol% phenylenediamine and 10-90 mol% bisaminophenoxybenzene on the basis of the diamines. |
