| 摘要 |
PROBLEM TO BE SOLVED: To perform the lamination with metal foil under a relatively gentle condition by using a polyamic acid soln. forming substrate polyimide having an imide unit represented by specific formula and using a soln. of polyimide having a specific compsn. composed of an imide unit represented by a specific formula or a precursor thereof. SOLUTION: An a polyamic acid soln. for a substrate layer, a polyamic acid soln. forming substrate polyimide having an imide unit represented by formula I is used. As a soln. of polyimide for a thin layer or a precursor thereof, a soln. of polyimide consisting of imide units A, B represented by formulae II, III (wherein R is a tetravalent aromatic residue and R' is a divalent aromatic or aliphatic residue) and characterized by that A is 80-100mol% and B is 20-0mol%) or a precursor thereof is used. These solns. are extruded to a support to form a solvent-containing multilayered extrudate which is, in turn, heated and dried to be imidated to obtain a multilayered polyimide film low in the coefficient of thermal and linear expansion. |
