EPOXY RESIN COMPOSITION, PREPREG, AND FIBER-REINFORCED COMPOSITE MATERIAL

An object of the present invention is to provide an epoxy resin composition excellent in elastic modulus and strength, and a prepreg and a fiber reinforced composite material with the epoxy resin composition. The present invention is the epoxy resin composition including the following components [A] to [C] and satisfying the following conditions (1) to (3):[A]: epoxy resin[B]: aromatic diamine[C]: a compound having a boiling point of 130°C or more and a molecular weight m of 50 or more and 250 or less, the compound having no epoxy group in the molecule and having substantially no curing ability of an epoxy resin(1): at least a part of the component [C] satisfies that the sum of the polar component and the hydrogen bond component in the Hansen solubility parameters is 10.0 or more.(2): at least a part of the component [C] satisfies that the Hansen solubility parameter distance L to the component [A] is 20.0 or less.(3): the ratio H/E between the amount by mole, E, of the epoxy group of the component [A] and the amount by mole, C, of the component [C] satisfying both the condition (1) and the condition (2) is 0.01 or more and 0.20 or less.(4): the viscosity at 70°C for 2 hours is 5.0 times or less the initial viscosity at 70°C.