| abstract |
A flexible printed board is which has increased bonding strength, with which dispersion of the bonding strength can be prevented, the quality of which can be uniformed, with which curling can satisfactorily be prevented, which exhibits excellent dimensional stability and with which a precise circuit can satisfactorily be formed. A flexible printed board has a copper foil on which first and second polyimide-resin layers are sequentially laminated. The first polyimide layer made contact with the copper foil is formed by forming, turning into an imide, a polyimide precursor which contains polyamic acid components prepared owing to reactions of acid anhydride and amine and polyimide components prepared owing to reactions of acid anhydride and isocyanate. |