EPOXY RESIN COMPOSITION FOR PREPREG, AND PREPREG
The epoxy resin composition for a prepreg according to an embodiment of the present invention contains (A) an epoxy resin, (B) a curing agent or a curing accelerator, (C) silica microparticles, and (D) core-shell rubber particles, the epoxy resin composition containing from 1 to 5 parts by mass of (C) the silica microparticles and from 2 to 10 parts by mass of (D) the core-shell rubber particles per 100 parts by mass of (A) the epoxy resin, and a mass ratio of (C) the silica microparticles to (D) the core-shell rubber particles, in terms of (C)/(D), being from 1/1 to 1/5.
1 . An epoxy resin composition for a prepreg, the epoxy resin composition comprising:
(A) an epoxy resin;
(B) a curing agent or a curing accelerator;
(C) silica microparticles; and
(D) core-shell rubber particles;
the epoxy resin composition comprising, per 100 parts by mass of (A) the epoxy resin, from 1 to 5 parts by mass of (C) the silica microparticles and from 2 to 10 parts by mass of (D) the core-shell rubber particles, and
a mass ratio of (C) the silica microparticles to (D) the core-shell rubber particles, in terms of (C)/(D), being from 1/1 to 1/5.
2 . The epoxy resin composition for a prepreg according to claim 1 , wherein, when viscoelasticity is measured at a temperature of 70° C. and a frequency of 1 Hz using parallel plates, tan δ at 1% strain is less than 1 and tan δ at 100% strain is more than 1.
3 . The epoxy resin composition for a prepreg according to claim 1 , wherein (A) the epoxy resin does not contain a nitrogen atom.
4 . The epoxy resin composition for a prepreg according to claim 1 , wherein an average particle diameter of (C) the silica microparticles is from 5 nm to 100 nm.
5 . The epoxy resin composition for a prepreg according to claim 1 , wherein an average particle diameter of (D) the core-shell rubber particles is from 10 nm to 10 μm.
6 . The epoxy resin composition for a prepreg according to claim 1 , the epoxy resin composition further comprising from 5 to 50 parts by mass of a thermoplastic resin per 100 parts by mass of (A) the epoxy resin.
7 . The epoxy resin composition for a prepreg according to claim 6 , wherein the thermoplastic resin is a phenoxy resin.
8 . A prepreg comprising the epoxy resin composition for a prepreg according to claim 1 and a reinforcing fiber.