Abstract: An epoxy resin composition including [A1] a hardener represented by Formula (1), and [B] an aromatic epoxy resin having tri- or higher functionality, wherein a carbon nuclear relaxation time T1C corresponding to a benzene ring carbon atom in the main backbone of Formula (1) assigned to 130 ppm in a solid-state 13C-NMR spectrum is 42 seconds or longer, and a prepreg and a carbon fiber-reinforced composite material obtained using the epoxy resin composition: wherein X represents any one selected from —CH2—, —O—, —CO—, —C(?O)O—, —S—, —SO2—, and —NHC(?O)—; n represents 1 to 5; and R1 to R6 each represent at least one selected from the group consisting of a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 4 or less carbon atoms, and an a halogen atom, wherein when X is —C(?O)O— or —NHC(?O)—, X may be in either direction.

Abstract: Provided are: an epoxy resin composition which enables the production of a carbon-fiber-reinforced composite material having excellent tensile strength and compressive strength and suitable as a material for structures; a prepreg; and a carbon-fiber-reinforced composite material. An epoxy resin composition characterized by comprising at least [A] an epoxy resin having a structure represented by formula (1), [B] an epoxy resin having at least one amine-type glycidyl group or at least one ether-type glycidyl group and having a liquid form at 40° C. and [C] a curing agent; and a prepreg and a carbon-fiber-reinforced composite material, each produced using the epoxy resin composition. (In the formula, R1 to R4 independently represent at least one atom or group selected from the group consisting of a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 4 or less carbon atoms, and a halogen atom.

Abstract: An epoxy resin composition including [A1] a hardener represented by Formula (1), and [B] an aromatic epoxy resin having tri- or higher functionality, wherein a carbon nuclear relaxation time T1C corresponding to a benzene ring carbon atom in the main backbone of Formula (1) assigned to 130 ppm in a solid-state 13C-NMR spectrum is 42 seconds or longer, and a prepreg and a carbon fiber-reinforced composite material obtained using the epoxy resin composition: wherein X represents any one selected from —CH2—, —O—, —CO—, —C(?O)O—, —S—, —SO2—, and —NHC(?O)—; n represents 1 to 5; and R1 to R6 each represent at least one selected from the group consisting of a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 4 or less carbon atoms, and an a halogen atom, wherein when X is —C(?O)O— or —NHC(?O)—, X may be in either direction.

Abstract: Provided are: an epoxy resin composition which enables the production of a carbon-fiber-reinforced composite material having excellent tensile strength and compressive strength and suitable as a material for structures; a prepreg; and a carbon-fiber-reinforced composite material. An epoxy resin composition characterized by comprising at least [A] an epoxy resin having a structure represented by formula (1), [B] an epoxy resin having at least one amine-type glycidyl group or at least one ether-type glycidyl group and having a liquid form at 40° C. and [C] a curing agent; and a prepreg and a carbon-fiber-reinforced composite material, each produced using the epoxy resin composition. (In the formula, R1 to R4 independently represent at least one atom or group selected from the group consisting of a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 4 or less carbon atoms, and a halogen atom.