# US 12,767,773 B2 · Epoxy resin composition for fiber-reinforced composite material, fiber-reinforced composite material, and method for producing fiber-reinforced composite material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,767,773 B2 - Document ID: US12767773B2 - Status: Granted - Kind: B2 - Application number: 18/275,456 - Filed: 2022-02-10 - Published: 2024-04-11 - Granted: 2026-10-20 - Earliest claimed: 2021-02-18 - Assignees: Toray Industries, Inc. - Applicants: Toray Industries, Inc. - Inventors: Kazunori Hondo - Web page: https://patentgrep.com/patent/US12767773B2 ## CPC - C08J 5/042: {with carbon fibres} - C08J 5/10: characterised by the additives used in the polymer mixture - C08J 2363/02: Polyglycidyl ethers of bis-phenols - C08J 2377/00: Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) ## Abstract Provided is an epoxy resin composition and a fiber-reinforced composite material using the epoxy resin composition, where the epoxy resin composition is capable of maintaining a low viscosity while being injected into a reinforcing fiber substrate and is also capable of imparting to a fiber-reinforced composite material high-level physical properties required for use as a structural material even in cases where the temperature increase rate during thermal curing is low, where the epoxy resin composition contains [A] tetraglycidyl diaminodiphenylmethanein an amount of not less than 70% by mass and not more than 90% by mass of total epoxy resin components taken as 100% by mass, [B] a bisphenol F-type epoxy resin in an amount of not less than 10% by mass and not more than 30% by mass by mass of total epoxy resin components taken as 100% by mass, [C] 4,4′-methylenebis(3-chloro-2,6-diethylaniline), and [D] 4,4′-methylenebis(3,3′,5,5′-tetraisopropylaniline). ## Claims ### Claim 1 An epoxy resin composition for fiber-reinforced composite material, comprising [A] tetraglycidyl diaminodiphenylmethane in an amount of not less than 70% by mass and not more than 90% by mass of total epoxy resin components taken as 100% by mass, [B] a bisphenol F-type epoxy resin having a resin viscosity at 50° C. in a range of 1,000 to 8,000 mPa·s in an amount of not less than 10% by mass and not more than 30% by mass by mass of total epoxy resin components taken as 100% by mass, [C] 4,4′-methylenebis(3-chloro-2,6-diethylaniline), and [D] 4,4′-methylenebis(3,3′,5,5′-tetraisopropylaniline). ### Claim 2 (depends on 1) The epoxy resin composition of claim 1 for fiber-reinforced composite material, further comprising [E] 4,4′-methylenebis(2-isopropyl-6-methylaniline). ### Claim 3 (depends on 1) The epoxy resin composition of claim 1 for fiber-reinforced composite material, further comprising [F] core-shell rubber particles having a volume average particle diameter of not less than 50 nm and not more than 300 nm and having epoxy groups in the shell. ### Claim 4 (depends on 1) The epoxy resin composition of claim 1 for fiber-reinforced composite material, wherein the resin viscosity n (mPa·s) of the epoxy resin composition is within the following range: 20≤n≤200 when measured with an E-type viscometer after heating under isothermal conditions at 120° C. for 240 minutes. ### Claim 5 (depends on 1) The epoxy resin composition of claim 1 for fiber-reinforced composite material, wherein gelation occurs in the temperature range of 170° C. to 185° C. when the epoxy resin composition is heated from 70° C. at a temperature increase rate of 0.5° C./min. ### Claim 6 (depends on 1) A fiber-reinforced composite material, comprising a cured product of the epoxy resin composition of claim 1 for fiber-reinforced composite material and a reinforcing fiber substrate. ### Claim 7 (depends on 6) The fiber-reinforced composite material of claim 6, wherein the reinforcing fiber substrate is a preform formed by stacking a plurality of sheets of reinforcing fiber substrate bonded by a nonwoven form of binder. ### Claim 8 (depends on 7) The fiber-reinforced composite material of claim 7, wherein the nonwoven form of the binder is composed of a polyamide having a melting temperature of 165° C. or higher and 180° C. or lower. ### Claim 9 (depends on 7) The fiber-reinforced composite material of claim 7, wherein the amount of the nonwoven form of the binder applied to the surface of the sheets of reinforcing fiber substrate is not less than 0.5 g/m2 and not more than 10 g/m2 on each side. ### Claim 10 (depends on 6) The fiber-reinforced composite material of claim 6, wherein a reinforcing fiber as a component of the reinforcing fiber substrate is a carbon fiber. ### Claim 11 (depends on 1) A method of producing a fiber-reinforced composite material, the method comprising injecting the epoxy resin composition of claim 1 for fiber-reinforced composite material heated to a temperature of 50° C. or higher and 130° C. or lower into a reinforcing fiber substrate placed in a mold heated to a temperature of 90° C. or higher and 180° C. or lower; impregnating the reinforcing fiber substrate with the epoxy resin composition; and curing the epoxy resin composition in the mold.