An electronic circuit device comprises a resin composition including 90 to 100 weight percent of a curable epoxy-modified aromatic vinyl-conjugated diene block copolymer, optionally up to 10 weight percent of an epoxy resin, and an effective amount of an epoxy curative, the weight percent of the copolymer and epoxy resin being based on the weight of the epoxy bearing material exclusive of curative. The resin composition can be used as an electronic adhesive, covercoat, or encapsulant. The electronic circuit device exhibits superior heat and moisture insensitivity, including the absence of voiding and delamination of the cured resin compostion from its substrate under conditions of 85° C. and 85% relative humidity for 168 hours followed by a temperature of 220° C. for 10 to 40 seconds.