Abstract: The present invention provides an epoxy resin composition comprising epoxy resin, phenolic resin, a cure accelerator and an inorganic filler; said epoxy resin comprises: (1) 20-50% of Formula I; (2) 10-40% of Formula II; and (3) 0-30% of Formula III and/or 0-40% of Formula IV, wherein Formula III and Formula IV are not 0% simultaneously; and wherein, R1 and R2 are independently hydrogen or alkyl of C1-C6; n is an integer from 0 to 50 in Formula I; the ratio of the number of phenolic hydroxyls in said phenolic resin to the number of epoxy groups in the epoxy resin mixture is 0.8-1.3; all said percentages are percentages relative to the total mass of the epoxy resin mixture.

Abstract: The present invention provides an epoxy resin composition comprising epoxy resin, phenolic resin, a cure accelerator and an inorganic filler; said epoxy resin comprises: (1) 20-50% of Formula I; (2) 10-40% of Formula II; and (3) 0-30% of Formula III and/or 0-40% of Formula IV, wherein Formula III and Formula IV are not 0% simultaneously; and wherein, R1 and R2 are independently hydrogen or alkyl of C1-C6; n is an integer from 0 to 50 in Formula I; the ratio of the number of phenolic hydroxyls in said phenolic resin to the number of epoxy groups in the epoxy resin mixture is 0.8-1.3; all said percentages are percentages relative to the total mass of the epoxy resin mixture.