| 摘要 |
PURPOSE:To provide the title high-modulus film excellent in resistance to water and moisture and dimensional stability, useful for flexible printing circuit boards, etc., made up of each specific two kinds of recurring unit. CONSTITUTION:The objective film made up of two kinds of recurring unit of formulas I and II (X is H or F), respectively, with the molar ratio I/II of (40:60)-(60:40). The present film can be obtained from a polyamic acid copolymer solution as precursor, which can be prepared by polymerization, in an organic polar solvent, between equimolar amounts of an acid anhydride and diamine component. |
