Abstract: A reinforced-fiber sheet impregnated with a matrix resin, a protective film having an irregular surface is applied to at least one surface of the reinforced-fiber sheet impregnated with the matrix resin such that the irregular surface faces the reinforced-fiber sheet. The thus-formed reinforced-fiber sheet covered with a protective film is kept at a temperature of 50-130° C. for four hours or more such that the viscosity of the impregnated resin is 100-10000 poise.

Abstract: The present invention relates to a prepreg which is free from the phenomenon that air is trapped between layers to generate voids, has good handling characteristics and can produce molded articles having any complicated shape and also relates to a method of producing the prepreg. A reinforced-fiber sheet is impregnated with a matrix resin so as to form a continuous resin layer at least in the inside thereof, and then, a protective film having an irregular surface is applied to at least one surface of the reinforced-fiber sheet impregnated with the matrix resin such that the irregular surface faces the reinforced-fiber sheet. In this state, the prepreg is allowed to leave at 30 to 60° C. under the atmosphere for 12 hours or more.

Abstract: The present invention relates to a prepreg which is free from the phenomenon that air is trapped between layers to generate voids, has good handling characteristics and can produce molded articles having any complicated shape and also relates to a method of producing the prepreg. A reinforced-fiber sheet is impregnated with a matrix resin so as to form a continuous resin layer at least in the inside thereof, and then, a protective film having an irregular surface is applied to at least one surface of the reinforced-fiber sheet impregnated with the matrix resin such that the irregular surface faces the reinforced-fiber sheet. In this state, the prepreg is allowed to leave at 30 to 60° C. under the atmosphere for 12 hours or more.

Abstract: Epoxy resin compositions comprising (a) an epoxy resin, (b) a latent curing agent with curing power at 100° C. or below and (c) an aromatic amine-based curing agent and/or an alicyclic amine-based curing agent, which are curable in two stages, or epoxy resin compositions further comprising (d) a curing accelerator, as well as a prepregs comprising reinforcing fiber materials impregnated with the epoxy resin compositions. The compositions give die-releasable cured products by primary curing at low temperature, give highly heat-resistant cured products by secondary curing, and exhibit satisfactory stability at room temperature.

Abstract: Epoxy resin compositions comprising (a) an epoxy resin, (b) a latent curing agent with curing power at 100° C. or below and (c) an aromatic amine-based curing agent and/or an alicyclic amine-based curing agent, which are curable in two stages, or epoxy resin compositions further comprising (d) a curing accelerator, as well as a prepregs comprising reinforcing fiber materials impregnated with the epoxy resin compositions. The compositions give die-releasable cured products by primary curing at low temperature, give highly heat-resistant cured products by secondary curing, and exhibit satisfactory stability at room temperature.