Epoxy resin composition for fiber-reinforced composite material, fiber-reinforced composite material, and production method thereof

An epoxy resin composition for a fiber-reinforced composite material, the epoxy resin composition comprising:

• an epoxy resin;
• and
• a curing agent,
• the fiber-reinforced composite material is able to be produced in which the epoxy resin composition is injected and impregnated into a reinforcing fiber substrate placed in a heated mold, and cured in the mold, wherein
• tetraglycidyldiaminodiphenylmethane [A] is contained at a content of 70 parts by mass or more and 90 parts by mass or less based on 100 parts by mass of all epoxy resin components,
• 4,4′-methylenebis(2-isopropyl-6-methylaniline) [B] is contained at a content of 80 parts by mass or more and 100 parts by mass or less based on 100 parts by mass of a total curing agent component,
• a bisphenol F type epoxy resin [C] is contained at a content of 10 parts by mass or more and 30 parts by mass or less based on 100 parts by mass of all the epoxy resin components,
• a resin viscosity at 30° C. represented by η30 (unit:
• mPa·s) and a resin viscosity at 80° C. represented by η80 (unit:
• mPa·s) satisfy 200≤η30/η80≤500 and 50≤η80≤180, and
• the reinforcing fiber substrate is a preform having a connection by a binder having a nonwoven fabric form made of nylon 12.