# US 2022/0033641 A1 · Sheet molding compound and 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 2022/0033641 A1 - Document ID: US20220033641A1 - Status: Published application - Kind: A1 - Application number: 17/277,385 - Filed: 2019-11-01 - Published: 2022-02-03 - Earliest claimed: 2018-11-27 - Assignees: Toray Industries, Inc. - Applicants: Toray Industries, Inc. - Inventors: Norikazu ISHIKAWA; Kazunori HONDO; Nobuyuki TOMIOKA - Web page: https://patentgrep.com/patent/US20220033641A1 ## CPC - C08J 5/243: {using carbon fibres} - C08L 63/00: Compositions of epoxy resins; Compositions of derivatives of epoxy resins - C08G 18/0842: {in the presence of liquid diluents (C08G18/0804 takes precedence)} - C08G 18/168: {Organic compounds} - C08G 18/1875: {containing ammonium salts or mixtures of secondary of tertiary amines and acids} - C08G 18/2027: {having two nitrogen atoms in the ring} - C08G 18/58: Epoxy resins {(C08G18/42, C08G18/48 take precedence; reaction products of epoxy resins with at least equivalent amounts of compounds containing active hydrogen C08G18/6407, with at least equivalent amounts of amines C08G18/6415; polymeric products of isocyanates or isothiocyanates with epoxy compounds having no active hydrogen C08G18/003)} - C08G 18/7664: {containing alkylene polyphenyl groups} - C08G 18/7671: {containing only one alkylene bisphenyl group} - C08G 59/4021: {Ureas; Thioureas; Guanidines; Dicyandiamides} - C08J 5/042: {with carbon fibres} - C08G 2120/00: Compositions for reaction injection moulding processes - C08J 2363/00: Characterised by the use of epoxy resins; Derivatives of epoxy resins - C08J 2475/00: Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers - C08J 2479/00: Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen, or carbon only, not provided for in groups C08J2461/00 - C08J2477/00 - C08L 2205/03: containing three or more polymers in a blend - 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) - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS ## Abstract The present invention enables the achievement of: an SMC which has excellent flexibility, while being suppressed in tackiness; and a fiber-reinforced composite material which uses this SMC, thereby being reduced in voids after molding. In order to achieve the above, a sheet molding compound according to the present invention has the configuration described below. Specifically, a sheet molding compound according to the present invention is formed from reinforcing fibers and a resin composition, and has a weight content of the fibers of from 40% to 60% (inclusive) and an air bubble content of from 5% by volume to 30% by volume (inclusive), while satisfying the formulae below in a dynamic viscoelasticity measurement at 25° C. 105 Pa G′ (s)≤109 Pa 1≤G′(s)/G″ (s)≤5 G′(s): storage elastic modulus (Pa) of sheet molding compound at 25° C. G″(s): loss elastic modulus (Pa) of sheet molding compound at 25° C. ## Claims ### Claim 1 A sheet molding compound comprising a reinforcing fiber and a resin composition, having a weight content of the reinforcing fiber of 40% or more and 60% or less, having a porosity of 5% by volume or more and 30% by volume or less, and satisfying the following formulas in dynamic viscoelasticity measurement at 25° C.: 105 Pa≤G′(s)≤109 Pa 1≤G′(s)/G″(s)≤5 G′(s): Storage modulus [Pa] of sheet molding compound at 25° C. G″(s): Loss modulus [Pa] of sheet molding compound at 25° C. ### Claim 2 (depends on 1) The sheet molding compound according to claim 1, wherein the storage modulus G′(s) at 70° C. is 105 Pa or more and 107 Pa or less. ### Claim 3 (depends on 1) The sheet molding compound according to claim 1, which satisfies the following formulas in the dynamic viscoelasticity measurement at 25° C. of the resin composition, 104 Pa≤G′(r)≤108 Pa 1≤G′(r)/G″(r)≤30 G′(r): Storage modulus [Pa] of resin composition at 25° C. G″(r): Loss modulus [Pa] of resin composition at 25° C. ### Claim 4 (depends on 1) The sheet molding compound according to claim 1, comprising voids composed of carbon dioxide. ### Claim 5 (depends on 1) The sheet molding compound according to claim 1, wherein a number average length of the voids in the sheet molding compound is 10 μm or more and 2000 μm or less. ### Claim 6 (depends on 1) The sheet molding compound according to claim 1, comprising an isocyanate compound as a component (A) in the resin composition. ### Claim 7 (depends on 1) The sheet molding compound according to claim 1, which comprises a hydroxyl group-containing epoxy resin as a component (B) in the resin composition. ### Claim 8 (depends on 1) The sheet molding compound according to claim 1, wherein the resin composition contains at least one compound selected from the group consisting of a quaternary ammonium salt, a phosphonium salt, an imidazole compound, and a phosphine compound as a component (C). ### Claim 9 (depends on 1) The sheet molding compound according to claim 1, wherein the reinforcing fiber is carbon fiber. ### Claim 10 (depends on 1) A fiber-reinforced composite material obtained by curing the sheet molding compound according to claim 1. ### Claim 11 (depends on 1) A method of producing the sheet molding compound according to claim 1, the method comprising impregnating a reinforcing fiber with a resin composition and then performing heating under a condition satisfying the following formulas: 5000≤(T1.5×t)≤15000 25≤T≤80 T: thickening temperature [° C.] t: Thickening time [hour] at T.