Patent ID: 8142875

Claim:
An epoxy resin composition for fiber-reinforced composite materials, comprising: an epoxy resin (A) that is in a liquid state at room temperature; a thermoplastic resin (B) that dissolves in the epoxy resin (A) at a temperature not less than 90° C.; thermosetting resin particles (C) that do not completely dissolve in the epoxy resin (A) at a temperature less than 90° C., but completely dissolve in the epoxy resin (A) upon heating of the composition and have a softening point of not less than 120° C.; and a curing agent (D), wherein the thermosetting resin particles (C) are made of an epoxy-based resin comprising bisphenol A-type epoxy resin that is in a solid state at room temperature, and wherein the epoxy resin composition contains, with respect to 100 parts by weight of the epoxy resin (A), 30 to 50 parts by weight of the thermoplastic resin (B) and 2 to 20 parts by weight of the thermosetting resin particles (C).