Abstract: A method for producing a rigid resin mold for preparing plastic moldings which comprises:(1) preparing a composition (I) consisting essentially of(A) a cyanate ester resin composition, and(B-1) a metallic substance which does not substantially accelerate gelation of the cyanate ester resin composition (A),(2) preparing a composition (II) consisting essentially of(C) epoxy resin, and(B-2) a metallic substance which accelerates gelation of the cyanate ester resin composition (A) and does not substantially accelerate gelation of the epoxy resin (C) at temperatures below or equal to 100.degree. C.,(3) mixing composition (I) of step (1) and composition (II) of step (2) to form composition (III),(4) casting composition (III) of step (3) into a mold(5) and gelling the cast resin.

Abstract: A process for producing a curable resin which comprises reacting (a) at least one cyanate ester compound selected from the group consisting of polyfunctional cyanate esters having two or more cyanato groups per one molecule, prepolymers of the cyanate esters or mixtures thereof with (b) at least one compound having hydroxy group(s) and radical-polymerizable unsaturated double bond(s) in its molecule, the cyanate ester compound (a) and the compound (b) being used so that the ratio of the cyanato group to the hydroxy is in the range of from about 1:0.1 to about 1:2, in the presence of (c) a radical polymerization inhibitor at a temperature of about 80.degree.-about 140.degree. C.The curable resin produced according to the present invention is capable of giving cured products having excellent heat resistance and electrical properties.