PURPOSE: To provide the titled compsn. which has good storage stability at a temp. not higher than room temp. and gives cured articles having excellent heat resistance, electrical characteristics, etc. by heating, by incorporating an org. Al compd. and an amine compd. in an epoxy/silicone copolymer.
CONSTITUTION: An epoxy resin-modified silicone resin compsn. consists of 100pts. wt. epoxy/silicone copolymer (A) obtd. by subjecting an organosilicon compd. having an average composition of the formula [wherein R 1 is a (substd.) monovalent hydrocarbon group; R 2 is H, a (substd.) monovalent hydrocarbon group; 0.2≤a≤4.0, 0.01≤b<4, a+b≤4] and an epoxy resin having at least one hydroxyl group and at least one epoxy group per molecule to a dehydration reaction or an alcohol-removing reaction, 0.001W3pts.wt. at least one Al compd. (B) selected from aluminum chelate compds. and aluminum alcoholate compds. and 0.005W 3pts.wt. amine compd. (C).