Abstract: The embodiments herein relate to a benzoxazine resin composition, a prepreg, and a carbon fiber-reinforced composite material. More specifically, the embodiments herein relate to a benzoxazine resin composition that provides a carbon fiber-reinforced composite material that is suitable for use as a manufacture material due to its superior mechanical strength in extreme use environments, such as high temperature and high moisture, as well as a prepreg, and a carbon fiber-reinforced composite material. An embodiment comprises a benzoxazine resin composition having a multifunctional benzoxazine resin; a multifunctional epoxy resin that is a liquid at 40° C. and has three or more glycidyl groups; a sulfonate ester; and optionally at least one thermoplastic resin. The resin may include an interpenetrating network structure after curing.

Abstract: A prepreg containing at least the following components [A]-[F], wherein the ratio Ne/Nd of the number of structures Ne of component [F] present in a range of outside 110% of the particle diameter of component [E] and the number of structures Nd of component [F] present in a range outside 110% of the particle diameter of component [D] is 0.25 or higher. [A]: Carbon fibers, [B] thermosetting resin, [C]: curing agent, [D]: particles composed mainly of thermoplastic resin having a primary particle number-average particle size of 5-50 ?m, [E]: conductive particles different from component [D] and having a primary particle number-average particle size in the range of a specific expression, [F]: filler comprising a carbon material.

Abstract: Disclosed is a carbon-fiber-reinforced composite material that is suitable for use as a construction material and exhibits high mechanical strength in harsh usage environments such as low-temperature environments and high-temperature moisture-absorbing environments. Also disclosed are an epoxy resin composition for producing the aforementioned carbon-fiber-rein-forced composite material and a prepreg obtained through the use of said epoxy resin composition. Said epoxy resin composition comprises at least the following constituents, by mass with respect to the total mass of the composition: (A) between 20% and 80% of an epoxy resin having the structure represented by formula (1); and (B) between 10% and 50% of an epoxy resin that has at least two ring structures with four or more members each and also has one amine glycidyl or ether glycidyl directly connected to a ring structure.

Abstract: The embodiments herein relate to a benzoxazine resin composition, a prepreg, and a carbon fiber-reinforced composite material. More specifically, the embodiments herein relate to a benzoxazine resin composition that provides a carbon fiber-reinforced composite material that is suitable for use as a manufacture material due to its superior mechanical strength in extreme use environments, such as high temperature and high moisture, as well as a prepreg, and a carbon fiber-reinforced composite material. An embodiment comprises a benzoxazine resin composition having a multifunctional benzoxazine resin; a multifunctional epoxy resin that is a liquid at 40° C. and has three or more glycidyl groups; a sulfonate ester; and optionally at least one thermoplastic resin. The resin may include an interpenetrating network structure after curing.

Abstract: Embodiments herein relate to a prepreg comprising a thermosetting resin, and reinforcing fibers in the thermosetting resin, wherein when the prepreg is cured in vacuum bag only conditions, and a method of making the same. The method also applies for autoclave processing. Embodiments also relate to a cured fiber reinforced composite material made by thermally curing the prepreg.

Abstract: An embodiment relates to a prepreg having a structure comprising a first layer and a second layer, wherein the prepreg comprises component (A) comprising a reinforcing fiber, component (B) comprising a thermosetting resin, and component (C) comprising a particle or a fiber of a thermoplastic resin, the component (C) is substantially locally distributed in the first layer and the prepreg is a partially impregnated prepreg.

Abstract: An epoxy compound of high-purity N,N,N?,N?-tetraglycidyl-3,4?-diaminodiphenyl ether is produced by: an addition reaction step of reacting 3,4?-diaminodiphenyl ether with epichlorohydrin in a polar protic solvent at 65 to 100° C. for 12 hours or longer to form N,N,N?,N?-tetrakis(3-chloro-2-hydroxypropyl)-3,4?-diaminodiphenyl ether; and a cyclization reaction step of reacting the N,N,N?,N?-tetrakis(3-chloro-2-hydroxypropyl)-3,4?-diaminodiphenyl ether with an alkali compound for dehydrochlorination.

Abstract: An epoxy compound of high-purity N,N,N?,N?-tetraglycidyl-3,4?-diaminodiphenyl ether is produced by: an addition reaction step of reacting 3,4?-diaminodiphenyl ether with epichloro-hydrin in a polar protic solvent at 65 to 100° C. for 12 hours or longer to form N,N,N?,N?-tetrakis(3-chloro-2-hydroxypropyl)-3,4?-diaminodiphenyl ether; and a cyclization reaction step of reacting the N,N,N?,N?-tetrakis(3-chloro-2-hydroxypropyl)-3,4?-diaminodiphenyl ether with an alkali compound for dehydrochlorination.

Abstract: Disclosed is a carbon-fiber-reinforced composite material that is suitable for use as a construction material and exhibits high mechanical strength in harsh usage environments such as low-temperature environments and high-temperature moisture-absorbing environments. Also disclosed are an epoxy resin composition for producing the aforementioned carbon-fiber-rein-forced composite material and a prepreg obtained through the use of said epoxy resin composition. Said epoxy resin composition comprises at least the following constituents, by mass with respect to the total mass of the composition: (A) between 20% and 80% of an epoxy resin having the structure represented by formula (1); and (B) between 10% and 50% of an epoxy resin that has at least two ring structures with four or more members each and also has one amine glycidyl or ether glycidyl directly connected to a ring structure.

Abstract: Disclosed is a fiber-reinforced composite material that is high in heat resistance and strength while being low in the content of volatile matter that volatilizes during curing. Also disclosed are an epoxy resin composition for production thereof, and a prepreg produced from the epoxy resin composition. Specifically the invention provides an epoxy resin composition comprising: [A] an epoxy resin comprising two or more ring structures each consisting of four or more members, and at least one amine type or ether type glycidyl group directly connected to the ring structures, [B] a tri- or more-functional epoxy resin, and [C] a curing agent, and also provides a prepreg produced by impregnating reinforcing fiber with the epoxy resin composition and a fiber-reinforced composite material produced by curing the prepreg.

Abstract: Disclosed is a fiber-reinforced composite material that is high in heat resistance and strength while being low in the content of volatile matter that volatilizes during curing. Also disclosed are an epoxy resin composition for production thereof, and a prepreg produced from the epoxy resin composition. Specifically the invention provides an epoxy resin composition comprising: [A] an epoxy resin comprising two or more ring structures each consisting of four or more members, and at least one amine type or ether type glycidyl group directly connected to the ring structures, [B] a tri—or more—functional epoxy resin, and [C] a curing agent, and also provides a prepreg produced by impregnating reinforcing fiber with the epoxy resin composition and a fiber-reinforced composite material produced by curing the prepreg.