ADHESIVE FOR FLEXIBLE PRINTED WIRING BOARD

摘要

PROBLEM TO BE SOLVED: To obtain a flexible printed wiring board which is free from the occurrence of a crack or a breakage on a metal foil that forms a patterned circuit even when subjected to repeated bending, of which the adhesive layer on the side of a base film or the side of a cover lay film has a high adhesive power and is free from peeling. SOLUTION: One or both of an adhesive layer on the side of a cover lay film and an adhesive layer on the side of a base film are formed from an adhesive made by dispersing resin particles 12 having a diameter of 1μm or larger and a modulus of elasticity of 1.0-2.5 GPa in a resin matrix 11 having a modulus of elasticity at ordinary temperature of 0.8 GPa or higher and a glass transition temperature of 80 deg.C or higher. It is desirable that the resin particles occupy 5-50 vol.% of the adhesive, and that the resin matrix used comprises a polyamide-imide resin while the resin particles used comprise an epoxy resin.