Patent ID: 9481789
Filing Date: 2016-11-01
CPC Classification: B32B,C08G,C08J,C08K,C08L,Y10T

Claim Text:
1. A method for producing a prepreg which contains reinforcing fibers and a matrix resin composition with the weight per square meter of the reinforcing fibers being 250-2,000 g/m 2 , the production method comprising the following steps (1)-(3): (1) a matrix resin composition blending step for obtaining a matrix resin composition having a viscosity of 12 Pa·s to 3,000 Pa·s at 30° C. by mixing an epoxy resin, a radically polymerizable unsaturated compound, an epoxy resin curing agent and a polymerization initiator that generates radicals, in said step the content of the radically polymerizable unsaturated compound relative to 100% by mass of the total of the epoxy resin and the radically polymerizable unsaturated compound being 10-25% by mass; (2) a matrix resin composition impregnating step for obtaining a prepreg precursor by impregnating a reinforcing fiber assembly being 250-2,000 g/m (3) a surface viscosity increasing step of obtaining a prepreg in which viscosity of the matrix resin composition is increased more in a superficial part than in a central part, by letting the polymerization initiator present in the superficial part of the prepreg precursor generate a radical, while not letting the polymerization initiator present in the central part generate a radical, wherein the step (2) includes the following steps (2-i) to (2-iii): (2-i) a matrix resin composition applying step comprising applying the matrix resin composition only to one face of a first reinforcing fiber sheet A (2-ii) a reinforcing fiber matrix laminating step comprising laminating a second reinforcing fiber sheet A (2-iii) a pressurizing step comprising impregnating the A