Cyanate ester resin composition and prepreg

1. A cyanate ester resin composition, comprising:

a cyanate ester resin (A);

a curing agent or a curing accelerator (B);

silica microparticles (C); and

core-shell rubber particles (D), wherein

the resin composition includes from 1 to 5 parts by mass of the silica microparticles (C) and from 2 to 10 parts by mass of the core-shell rubber particles (D) based on 100 parts by mass of the cyanate ester resin (A), and

a mass ratio of the silica microparticles (C) to the core-shell rubber particles (D) is from 1/1 to 1/5 as (C)/(D).

2. The cyanate ester resin composition according to claim 1 , wherein a tan δ at a strain 1% is less than 1 and a tan δ at a strain 100% is 1 or greater when viscoelasticity is measured at a temperature of 70° C. and a frequency 1 Hz on a parallel plate.

3. The cyanate ester resin composition according to claim 1 , wherein the cyanate ester resin (A) is a novolac type cyanate ester resin.

4. The cyanate ester resin composition according to claim 1 , wherein a compounded amount of the silica microparticles (C) per 100 parts by mass of the cyanate ester resin (A) is from 2 to 4 parts by mass.

5. The cyanate ester resin composition according to claim 1 , wherein a compounded amount of the core-shell rubber particles (D) per 100 parts by mass of the cyanate ester resin (A) is from 4 to 8 parts by mass.

6. The cyanate ester resin composition according to claim 1 , wherein a mass ratio of the silica microparticles (C) to the core-shell rubber particles (D) is from 1/1.5 to 1/4 as (C)/(D).

7. A prepreg comprising the cyanate ester resin composition described in claim 1 and a reinforcing fiber.

8. The prepreg according to claim 7 , wherein a content of the cyanate ester resin composition in the prepreg is from 30 to 60 mass %.