Patent ID: 6436467
Filing Date: 2002-08-20
Classification: B32B,C08G,C09D,C09J,H05K

Abstract:
A method of manufacturing a flexible printed board comprising the steps of:forming a first polyimide-precursor-layer by coating a conductor with varnish having a glass transition temperature of 250Â° C. or higher for a first polyimide precursor containing polyamic acid components prepared owing to reactions of acid anhydride and amine and expressed by a following chemical formula (3) and polyimide components prepared owing to reactions of acid anhydride and isocyanate and expressed by a following chemical formula (4); coating a surface of the first polyimide-precursor-layer with varnish for a second polyimide precursor composed of polyamic acid components prepared owing to reactions of acid anhydride and amine; and subjecting said first and second polyimide-precursor-layers to heat treatment so as to turn said first and second polyimide precursors into an imide so that said first and second polyimide-resin layers are formed, wherein a residual quantity of non-dried solvent and condensed water from volatization of said first and second polyimide-precursor-layers is 30% to 50%: where each of Ar1 and Ar2 is an aromatic group and n is an integer where each of Ar3 and Ar4 is an aromatic group and m is an integer.