US Patent 7883766 Prepreg

A prepreg is provided capable of being a composite material having suitable high heat resistance, impact resistance, and mechanical properties under high temperature and high humidity conditions. As the matrix resin, a composition including a specific epoxy resin component (A), a specific bifunctional epoxy resin (B), a specific tetrafunctional epoxy resin (C), and a specific aromatic amine compound (D) at specific proportions are used. Particularly, as the epoxy resin component (A), one obtained by mixing and heating a bifunctional epoxy resin (a1), a trifunctional epoxy resin (a2), a phenol compound (a3), and a specific polyamide resin (a4) is used so as to be able to solve the above-described problems.