Abstract: Provided is a thermosetting resin composition which achieves both high heat resistance and high bending strength as a fiber-reinforced composite material, and also has rapid curability that enables high cycle press forming, thermal stability, and storage stability. The thermosetting resin composition of the present invention is a thermosetting resin composition comprising an epoxy resin, an epoxy resin curing agent, an imidazole compound, and an epoxy resin curing accelerator, in which the epoxy resin curing agent is dicyandiamide or a derivative thereof, and the epoxy resin curing accelerator comprises a urea derivative having two or more dimethylureido groups in a molecule.

Abstract: Provided is a sheet molding compound having excellent thick portion-molding properties that can inhibit the occurrence of internal cracks even during the molding of a thick portion and enables a carbon fiber composite material molded article to be excellently released from a die. Also provided is a carbon fiber composite material molded article. The sheet molding compound of the present invention contains a fiber substrate (A) containing carbon fiber and a thermosetting resin composition (B), in which an average fiber length of the carbon fiber is 5 mm or more, and a volumetric molding shrinkage rate of the thermosetting resin composition (B) is 0.5% or more and 4.4% or less. Furthermore, the carbon fiber composite material molded article of the present invention has a thick portion having a thickness of 10 mm or more, in which the thick portion is formed of a cured material of the sheet molding compound of the present invention.

Abstract: A prepreg may include: a reinforcing fiber material including carbon fibers; and a resin composition with which the reinforcing fiber material is impregnated. The resin composition may include an epoxy resin (A), an amine curing agent (B), and an imidazole curing agent (C). The amine curing agent (B) may be present in a range of from 1 to 3.8 parts by mass, relative to 100 parts by mass of the epoxy resin (A). The amine curing agent (B) and the imidazole curing agent (C) may be present in a total amount of not more than 10 parts by mass, relative to 100 parts by mass of the epoxy resin (A). The imidazole curing agent may include an imidazole compound including, in its molecular structure, a triazine ring.

Abstract: A prepreg contains: a reinforcing fiber material; and a resin composition with which the reinforcing fiber material is impregnated. The resin composition contains an epoxy resin, an amine curing agent, and an imidazole curing agent. An amount of the amine curing agent is less than or equal to 3.8 parts by mass, relative to 100 parts by mass of the epoxy resin, and a sum of the amount of the amine curing agent and an amount of the imidazole curing agent is less than or equal to 10 parts by mass, relative to 100 parts by mass of the epoxy resin. The fiber-reinforced composite material is a cured product of the prepreg.

Abstract: A thermosetting resin composition (C) of which curing can be started at a relatively low temperature in a short time and a cured product exhibits high heat resistance, the thermosetting resin composition (C) comprising an epoxy resin; an epoxy resin curing agent; and an epoxy resin curing accelerator, wherein the epoxy resin curing agent contains an imidazole-based curing agent 1 which is not encapsulated in a microcapsule and a curing agent 2 which is encapsulated in a microcapsule, and the epoxy resin curing accelerator comprises a urea derivative.

Abstract: Provided is a thermosetting resin composition (C) of which curing can be started at a relatively low temperature in a short time and a cured product exhibits high heat resistance, the thermosetting resin composition (C) comprising an epoxy resin; an epoxy resin curing agent; and an epoxy resin curing accelerator, wherein the epoxy resin curing agent contains an imidazole-based curing agent 1 which is not encapsulated in a microcapsule and a curing agent 2 which is encapsulated in a microcapsule, and the epoxy resin curing accelerator comprises a urea derivative.

Abstract: A molding material that enables acquirement of a fiber-reinforced composite material which has excellent demoldability from a mold and excellent surface appearance, which contaminates a mold surface after molding less, and which has excellent mechanical properties and heat resistance; and a fiber-reinforced composite material which has excellent demoldability from a mold and surface appearance, which contaminates a mold surface after molding less, and which has excellent mechanical properties and heat resistance, are provided. A molding material of the present invention includes a component (A): an epoxy resin; a component (B): an epoxy resin curing agent; a component (C): a compound that has a solubility parameter of 11.2 or less and a melting point of 115° C. or lower; and a reinforcement fiber.

Abstract: Provided is a sheet molding compound which can inhibit the formation of burrs during press molding, enables a matrix resin to exhibit excellent fluidity and excellent quick curing properties during press molding, and makes it possible to obtain a fiber-reinforced composite excellent in mold release properties, mechanical characteristics, and heat resistance. The sheet molding compound of the present invention contains an epoxy resin composition and reinforcing fiber, in which a gel time of the epoxy resin composition is 30 to 140 seconds at 140° C., a temperature at the start of curing reaction of the epoxy resin composition is 70° C. to 115° C., and when b1 represents a viscosity of the epoxy resin composition measured at 30° C. 7 days after the preparation of the composition, and b2 represents a viscosity of the epoxy resin composition measured at 30° C. 14 days after the preparation of the composition, b1 and b2 satisfy b2/b1?5.

Abstract: An object of the present invention is to provide a molding material which can suppress film lifting, gives good peelability of release paper, and can produce therefrom a fiber-reinforced composite article with good demoldability from a metal mold, and a fiber-reinforced composite article. The molding material of the present invention comprises an epoxy resin composition comprising a component (A): an epoxy resin, a component (B): an epoxy resin curing agent, and a component (C): an unsaturated fatty acid ester compound having a melting point or pour point of 25° C. or lower; and a reinforcing fiber substrate, wherein the reinforcing fiber substrate is impregnated with the epoxy resin composition.

Abstract: Provided is a thermosetting resin composition which achieves both high heat resistance and high bending strength as a fiber-reinforced composite material, and also has rapid curability that enables high cycle press forming, thermal stability, and storage stability. The thermosetting resin composition of the present invention is a thermosetting resin composition comprising an epoxy resin, an epoxy resin curing agent, an imidazole compound, and an epoxy resin curing accelerator, in which the epoxy resin curing agent is dicyandiamide or a derivative thereof, and the epoxy resin curing accelerator comprises a urea derivative having two or more dimethylureido groups in a molecule.

Abstract: Provided is a thermosetting resin composition which achieves both high heat resistance and high bending strength as a fiber-reinforced composite material, and also has rapid curability that enables high cycle press forming, thermal stability, and storage stability. The thermosetting resin composition of the present invention is a thermosetting resin composition comprising an epoxy resin, an epoxy resin curing agent, an imidazole compound, and an epoxy resin curing accelerator, in which the epoxy resin curing agent is dicyandiamide or a derivative thereof, and the epoxy resin curing accelerator comprises a urea derivative having two or more dimethylureido groups in a molecule.

Abstract: The invention provides an epoxy resin composition that is easily B-staged despite containing an epoxy resin inherently difficult to B-stage, has a long pot life, has excellent processability and storage stability after B-staging, and make it possible to obtain a fiber-reinforced composite material having excellent flexural strength and flexural modulus. A molding material, including a thickened product of an epoxy resin composition; and a reinforcing fiber; wherein the epoxy resin composition including: a component (A): an aromatic epoxy resin; a component (B): an alicyclic diamine; a component (C): an epoxy resin curing agent that is not an alicyclic diamine; and a component (D): an aliphatic epoxy resin, wherein, when the viscosity at 25° C. immediately after preparation of the epoxy resin composition is taken as (a) and the viscosity at 25° C. after three hours from the preparation is taken as (b), the epoxy resin composition satisfies: (a)=0.1 to 25 Pa·s; (b)=0.1 to 25 Pa·s; and (b)/(a)?5.

Abstract: A prepreg contains: a reinforcing fiber material; and a resin composition with which the reinforcing fiber material is impregnated. The resin composition contains an epoxy resin, an amine curing agent, and an imidazole curing agent. An amount of the amine curing agent is less than or equal to 3.8 parts by mass, relative to 100 parts by mass of the epoxy resin, and a sum of the amount of the amine curing agent and an amount of the imidazole curing agent is less than or equal to 10 parts by mass, relative to 100 parts by mass of the epoxy resin. The fiber-reinforced composite material is a cured product of the prepreg.

Abstract: Provided is a sheet molding compound having excellent thick portion-molding properties that can inhibit the occurrence of internal cracks even during the molding of a thick portion and enables a carbon fiber composite material molded article to be excellently released from a die. Also provided is a carbon fiber composite material molded article. The sheet molding compound of the present invention contains a fiber substrate (A) containing carbon fiber and a thermosetting resin composition (B), in which an average fiber length of the carbon fiber is 5 mm or more, and a volumetric molding shrinkage rate of the thermosetting resin composition (B) is 0.5% or more and 4.4% or less. Furthermore, the carbon fiber composite material molded article of the present invention has a thick portion having a thickness of 10 mm or more, in which the thick portion is formed of a cured material of the sheet molding compound of the present invention.

Abstract: Provided is a thermosetting resin composition which achieves both high heat resistance and high bending strength as a fiber-reinforced composite material, and also has rapid curability that enables high cycle press forming, thermal stability, and storage stability. The thermosetting resin composition of the present invention is a thermosetting resin composition comprising an epoxy resin, an epoxy resin curing agent, an imidazole compound, and an epoxy resin curing accelerator, in which the epoxy resin curing agent is dicyandiamide or a derivative thereof, and the epoxy resin curing accelerator comprises a urea derivative having two or more dimethylureido groups in a molecule.

Abstract: The invention provides an epoxy resin composition that is easily B-staged despite containing an epoxy resin inherently difficult to B-stage, has a long pot life, has excellent processability and storage stability after B-staging, and make it possible to obtain a fiber-reinforced composite material having excellent flexural strength and flexural modulus. A molding material, including a thickened product of an epoxy resin composition; and a reinforcing fiber; wherein the epoxy resin composition including: a component (A): an aromatic epoxy resin; a component (B): an alicyclic diamine; a component (C): an epoxy resin curing agent that is not an alicyclic diamine; and a component (D): an aliphatic epoxy resin, wherein, when the viscosity at 25° C. immediately after preparation of the epoxy resin composition is taken as (a) and the viscosity at 25° C. after three hours from the preparation is taken as (b), the epoxy resin composition satisfies: (a)=0.1 to 25 Pa·s; (b)=0.1 to 25 Pa·s; and (b)/(a)?5.

Abstract: A molding material that enables acquirement of a fiber-reinforced composite material which has excellent demoldability from a mold and excellent surface appearance, which contaminates a mold surface after molding less, and which has excellent mechanical properties and heat resistance; and a fiber-reinforced composite material which has excellent demoldability from a mold and surface appearance, which contaminates a mold surface after molding less, and which has excellent mechanical properties and heat resistance, are provided. A molding material of the present invention includes a component (A): an epoxy resin; a component (B): an epoxy resin curing agent; a component (C): a compound that has a solubility parameter of 11.2 or less and a melting point of 115° C. or lower; and a reinforcement fiber.

Abstract: A sheet-molding compound comprising a thickened thermosetting resin composition and reinforcing fiber bundles. The thermosetting resin composition comprises components (A), (B) and (D). The content of component (D) is 10 parts by mass to 30 parts by mass with respect to 100 parts by mass of the total amount of epoxy resin. The final viscosity of the thickened thermosetting resin composition is 150 Pa·s to 20000 Pa·s, and the minimum viscosity is 2 Pa·s to 600 Pa·s, the final viscosity being higher than the minimum viscosity.

Abstract: Provided is a fiber-reinforced composite material molded article including a thick portion having a thickness equal to or greater than 10 mm, in which the thick portion has an inner layer which is formed of a cured material of a composite material (A) containing reinforcing fiber and an epoxy resin and a surface layer which is formed of a cured material of a composite material (B) containing reinforcing fiber and a vinyl ester resin.

Abstract: A sheet-molding compound comprising a thickened thermosetting resin composition and reinforcing fiber bundles. The thermosetting resin composition comprises components (A), (B) and (D). The content of component (D) is 10 parts by mass to 30 parts by mass with respect to 100 parts by mass of the total amount of epoxy resin. The final viscosity of the thickened thermosetting resin composition is 150 Pa·s to 20000 Pa·s, and the minimum viscosity is 2 Pa·s to 600 Pa·s, the final viscosity being higher than the minimum viscosity.