PURPOSE: To obtain the titled prepreg having improved drillability, etc., by using a varnish obtained by compounding a silicone-modified epoxy resin with a polyfunctional phenol, a cure accelerator, a fluororesin or a polyolefin and a guanidine derivative.
CONSTITUTION: The objective prepreg can be produced by compounding (A) 100pts.(wt.) of an epoxy resin containing 1W100wt% silicone-modified epoxy resin produced by reacting (i) a bisphenol-A epoxy resin, (ii) tetrabromobisphenol A and (iii) a methoxy-containing silicone intermediate, e.g. the compound of formula (R is methyl, phenyl or methoxy; n is 0W3), with (B) a polyfunctional phenol, (C) 0.05W1pt. of a cure accelerator, preferably an imidazole compound having masked imino group, (D) 0.1W100pts. of a fluororesin or a polyolefin and (E) 0.1W1pt. of a guanidine derivative and impregnating and drying the resultant varnish in a substrate.
SHIBATA KATSUJI
MIYADERA YASUO
