| abstract |
Disclosed is an improved epoxy resin-based adhesive composition, which is particularly suitable for use in the preparation of a base sheet for flexible printed circuit boards as a laminate of an insulating plastic resin film and a foil of a metal such as copper as well as in the preparation of a coverlay film for protection of the circuit pattern of the metal foil in a flexible printed circuit board. The adhesive composition comprises, as a uniform blend, (a) an epoxy resin, (b) an acrylic rubber modified by carboxyl groups to have a specified content of the carboxyl groups, (c) a curing agent for the epoxy resin such as an aromatic amine compound and (d) a curing promoter, each in a specified weight proportion. |