RESIN COMPOSITION FOR USE IN FORMATION OF BONDING LAYER IN MULTILAYER FLEXIBLE PRINTED CIRCUIT BOARD, RESIN VARNISH, RESIN-COATED COPPER FOIL, MANUFACTURING METHOD FOR RESIN-COATED COPPER FOIL FOR USE IN MANUFACTURING OF MULTILAYER FLEXIBLE PRINTED CIRCUIT BOARD, AND MULTILAYER FLEXIBLE PRINTED CIRCUIT BOARD

摘要

Disclosed is a resin composition which prevents B-stage cracking, and prevents dust fall which can occur, for example, during a manufacturing process of flexible printed circuit boards, and which exhibits a good balance of fold resistance, heat resistance, and resin flow performance and the like. The resin composition, which is used to form the bonding layer for multilayering an inner flexible printing board, is characterized by containing as components: (A): a solid epoxy resin having high heat resistance and a softening point of at least 50°C; (B): an epoxy resin curing agent comprising at least a biphenyl phenolic resin and/or a phenol aralkyl phenolic resin; (C): a rubber modified polyamide-imide resin which is soluble in a solvent having a boiling point in the range between 50°C and 200°C; (D): an organic phosphorus-containing fire retardant; and (E): a biphenyl epoxy resin.