Prepreg and fiber reinforced composite material
The objective of the present invention is to provide a prepreg and a fiber reinforced composite material using this prepreg. This prepreg has good handleability, is suitable for producing a reinforced composite material in a short-time and without using an autoclave, and is capable of yielding a fiber reinforced composite material exhibiting excellent impact resistance, wherein the occurrence of voids has been suppressed. To attain the objective, this prepreg comprises a reinforced fiber [A] that is layered and partially impregnated with an epoxy resin composition containing an epoxy resin [B] and a hardener [C], the impregnation rate φ being 30 to 95%. In this prepreg, a thermoplastic resin [D] insoluble in the epoxy resin [B] is distributed unevenly over a surface on one side of the prepreg, and a portion not impregnated with the epoxy resin composition is localized in the layer of the reinforced fiber [A] on the side where the thermoplastic resin [D] is distributed unevenly. This prepreg has a localization parameter σ, which defines the degree of the localization to be in the range of 0.10<σ<0.45.
1. A prepreg comprising:
reinforced fibers [A] arranged in a layer form,
an epoxy resin composition containing an epoxy resin [B] and a hardener [C], the epoxy resin composition being partially impregnated into the reinforced fibers [A], and
a thermoplastic resin [D] that is insoluble in the epoxy resin [B] and is localized at a surface on one side of the prepreg,
wherein the prepreg has a degree of impregnation φ with the epoxy resin composition of 30 to 95%,
in a layer of the reinforced fibers [A], a region un-impregnated with the epoxy resin composition shifts to the side where the thermoplastic resin [D] is localized, and
the prepreg has a shift parameter σ that defines a degree of the shift in a range of 0.10<σ<0.45.
2. The prepreg according to claim 1 , having an in-plane air permeability coefficient K of 2.0×(1−φ/100)×10 −14 [m 2 ] or more.
3. The prepreg according to claim 1 , wherein the reinforced fibers [A] are continuous fibers that are arranged unidirectionally.
4. The prepreg according to claim 1 , wherein the reinforced fibers [A] are in a form of a woven fabric.
5. The prepreg according to claim 1 , the epoxy resin composition is partially impregnated into the reinforced fibers [A] on both sides of the reinforced fibers [A].