| 摘要 |
PURPOSE:To obtain a prepreg having excellent storability, curability and moldability and suitable for multi-layered circuit boards. etc., by impregnating a substrate with a varnish containing a specific co-condensed multi-functional epoxy resin, a specified aromatic diamine and dicyandiamide as main components and subsequently drying the impregnated substrate. CONSTITUTION:A substrate such as glass fiber woven fabric is impregnated with a varnish containing (A) a co-condensed multi-functional epoxy resin obtained by reacting bisphenol A and/or tetrabromobisphenol A with a mixture of bisphenol A type and tetrabromobisphenol A type epoxy resins with a bisphenol A novolak epoxy resin, (B) dicyandiamide and (C) an aromatic diamine of the formula (R1-R4 are alkyl, H) as main components, followed by drying the impregnated product to obtain the objective prepreg. The components B and C are preferably used in an active hydrogen equivalent ratio of 1:(0.1-1.0) therebetween, and compounded in active hydrogen group amounts of 0.5-1.0, respectively, per the epoxy group. |
