Abstract:
Provided are: a fiber-reinforced composite material which is suppressed in morphology variation due to the molding conditions, while having excellent mode I interlaminar fracture toughness and excellent wet heat resistance; an epoxy resin composition for obtaining the fiber-reinforced composite material; and a prepreg which is obtained using the epoxy resin composition. An epoxy resin composition for fiber-reinforced composite materials, which contains at least the following constituent elements [A]-[F], and which is characterized by containing 5-25 parts by mass of constituent element [C] and 2-15 parts by mass of constituent element [E] per 100 parts by mass of the total epoxy resin blended therein. [A] A bifunctional amine type epoxy resin. [B] A tetrafunctional amine type epoxy resin. [C] A bisphenol F type epoxy resin having an epoxy equivalent weight of 450-4,500. [D] An aromatic amine curing agent. [E] A block copolymer having a reactive group that can be reacted with as epoxy resin. [F] Thermoplastic resin particles that are insoluble in an epoxy resin.
Abstract:
The invention provides a prepreg that can give a fiber-reinforced composite material exhibiting stable and excellent interlaminar fracture toughness and impact resistance under wide molding conditions. The prepreg includes at least a reinforcement fiber [A], a thermosetting resin [B], and the following component [C] wherein 90% or more of the material [C] is present inside a region of the prepreg that extends from any surface of the prepreg to a prepreg site having, from the surface, a depth of 20% of the thickness of the prepreg. The component [C] satisfies requirements that (i) the storage elastic modulus G′ of the material constituting the particles is more than 1 MPa, and 70 MPa or less at 180° C., and that (ii) the ratio of the storage elastic modulus G′ of the material constituting the particles at 160° C. to the storage elastic modulus G′ of the material at 200° C. ranges from 1 to 5; and is insoluble in the thermosetting resin [B].