Patent ID: 7041399

Claim:
A varnish for laminate or prepreg, comprising: a heat treatment product which is obtained by mixing together (a) an epoxy resin, (b) dicyandiamide, and (c) a compound having an imidazole ring so that the component (c) is present in an amount of 0.001 to 0.03% by weight, based on the weight of the component (a), and subjecting the resultant mixture to reaction for heat treatment in an organic solvent at a temperature of 70° C. to less than 140° C. so that all of the components are compatible with one another in the absence of a solvent; and (d) inorganic filler, wherein the component (c) is a compound represented by the following formula (2): wherein each of R 3 , R 4 and R 5 represents a hydrogen atom, a methyl group, an ethyl group, or a phenyl group, and R 6 is an optional divalent organic group.