INSULATING RESIN COMPOSITION

摘要

Disclosed is an insulating resin composition to be arranged on a base of a flexible printed wiring board, which contains a urethane (X), an epoxy resin (B) and a filler (C). This insulating resin composition is characterized in that the urethane (X) is a polyurethane-polyurea resin (A), a hydroxy group-containing urethane prepolymer (f), or a mixture of the polyurethane-polyurea resin (A) and the hydroxy group-containing urethane prepolymer (f). The polyurethane-polyurea resin (A) is obtained by reacting a polyamino compound (e) with an isocyanate group-containing urethane prepolymer (d) which is prepared by reacting a polyol compound (a),anorganic diisocyanate (b) and a carboxyl group-containing diol compound (c). The hydroxy group-containing urethane prepolymer (f) is obtained by reacting an polyol compound (a), an organic diisocyanate (b) and a carboxyl group-containing diol compound (c). The insulating resin composition is further characterized in that the filler (C) is an organic resin filler and the base is a thermoplastic resin base. This insulating resin composition exhibits good adhesion to the base as well as low warping property, flexural property, blocking resistance and flame retardancy.