An epoxy resin composition is provided comprising (A) an epoxy resin, (B) a phenolic resin curing agent, (C) an inorganic filler, (D) a cure accelerator, (E) an adhesion promoter, and (F) a metal oxide. The metal oxide (F) is a combination of a magnesium/aluminum ion exchanger, a hydrotalcite ion exchanger, and a rare earth oxide in a ratio of 0.5-20:0.5-20:0.01-10 pbw, relative to 100 pbw of epoxy resin (A) and curing agent (B) combined.