PURPOSE: To obtain prepreg for printed circuit board having improved drill processing properties, copper foil release strength, and shelf stability, by blending an epoxy resin with a novalak resin, a curing promoter, and dicyandiamide (derivative) to give varnish, impregnating the varnish into glass nonwoven fabric, etc.,k and drying it.
CONSTITUTION: (A) 100 pts. wt. epoxy resin such as brominated bisphenol A epoxy resin is blended with (B) 0.5W1.5 equivalent based on epoxy group in the component A of a novdolak resin such as phenolic novolak epoxy resin, (C) 0.01W5 pts. wt. curing promoter such as an imidazole compound whose secondary amino group is preferably masked with acrylonitrile, isocyanate, melamine acrylate, etc., and (D) 0.1W1 pt. wt. dicyandiamide or derivative obtained by adding an amine to it to give varnish, which is impregnate-d i-nto glass nonwoven fabric, which is dried at 80W200°C, to give the aimed prepreg.
SHIBATA KATSUJI
MIYADERA YASUO
