PREPREG, LAMINATE AND MULTILAYER PRINTED WIRING BOARD

摘要

PROBLEM TO BE SOLVED: To obtain a prepreg which can be processed without much dusting and is excellent for the formation of elaborate circuits by impregnating a polyarylate fiber base with a varnish containing a linear high-molecular-weight epoxy polymer, an isocyanate crosslinking agent, an at least difunctional epoxy resin and a phenol novolac curing agent in a specified ratio and converting the resin into stage B by heating. SOLUTION: The linear high-molecular-weight epoxy polymer is obtained by reacting a difunctional epoxy resin with a difunctional phenol in an epoxy group/phenolic hydroxyl group equivalent ratio of 1.0/(0.9-1.1). The crosslinking agent is one having isocyanate groups masked with 1.0-5.0 equivalents of a masking agent and is used in an amount of 0.1-2.0 equivalents per equivalent of the alcoholic hydroxyl groups of the high-molecular-weight epoxy polymer. 100 pts.wt. high-molecular-weight epoxy polymer is mixed with 10-200 pts.wt. at least difunctional epoxy resin. The curing agent is used in an amount of 0.1-2.0 equivalents, per equivalent of the epoxy groups of the at least difunctional epoxy resin.