POLYIMIDE FILM, ITS PRODUCTION METHOD, AND POLYIMIDE/METAL LAMINATE AND FLEXIBLE PRINTED CIRCUIT BOARD EACH PREPARED BY USING THE POLYIMIDE FILM

摘要

PROBLEM TO BE SOLVED: To provide a polyimide/metal laminate and a flexible printed circuit board each of which operates while retaining its performance even under severe conditions of high temperature and humidity and hence is suitable for an electric instrument circuit. SOLUTION: A polyimide film is prepared by immersing a partially cured and/or partially dried polyamic acid film in a solution of a polyamic acid and/or a polyimide containing 0.1-30 wt.% metal compound or by coating a partially cured and/or partially dried polyamic acid film with a solution of a polyamic acid and/or a polyimide containing 0.1-30 wt.% metal compound, and then converting the remaining amic acid into a polyimide. Thus obtained polyimide film gives a polyimide/metal laminate which has such an improved environmental resistance that the adhesive strength of 1 mm pattern width after the exposure to an environment with 100% RH at 121 deg.C for 96 h is at least 60% of the adhesive strength before the exposure.