| abstract |
To provide an epoxy resin composition that can afford a printed wiring board excellent in heat resistance, adhesiveness, prepreg storage stability, and insulation reliability. n An epoxy resin composition containing (A) an oxazolidone ring-containing epoxy resin, (B) a novolac-type epoxy resin, (C) a guanidine derivative, and (D) an imidazole as components, wherein the component (A) contains an isocyanuric ring as well as an oxazolidone ring and, the IR absorbance ratio of the isocyanuric ring to the oxazolidone ring is not less than 0.01 and not more than 0.1, the weight ratio of the component (A) to the component (B) is 5:95 to 95:5, the content of the component (C) and the content of the component (D) are 0.01 to 5 parts by weight and not more than 0.08 part by weight, respectively, based on 100 parts by weight of the total weight of the epoxy resins containing the component (A) and the component (B), and the bromine content based on a weight obtained by subtracting the weight of the component (C) and the weight of the component (D) from the weight of the resin composition is not less than 10% by weight and not more than 20% by weight. |