# US 5,344,689 A · Carbon fiber prepreg and carbon fiber reinforced resin composite > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,344,689 A - Document ID: US5344689A - Status: Granted - Kind: A - Application number: 08/030,264 - Filed: 1993-04-05 - Granted: 1994-09-06 - Earliest claimed: 1991-08-09 - Assignees: Kabushiki Kaisha Kobe Seiko Sho - Inventors: Shouaki Ide; Akira Shimamoto; Toshiaki Yutori; Masahiko Uchimura - Web page: https://patentgrep.com/patent/US5344689A ## CPC - B29C 70/20: oriented in a single direction, e.g. roofing or other parallel fibres {(B29C70/083, B29C70/226 take precedence)} - B32B 5/26: another layer {next to it} also being fibrous or filamentary {(relative arrangement of fibres or filaments of different layers B32B5/12)} - C08J 5/042: {with carbon fibres} - C08J 5/248: {using pre-treated fibres} - B29K 2105/10: {Cords, strands or rovings, e.g.} oriented {cords, strands or rovings} - B29K 2305/12: Iron - B29K 2307/00: Use of elements other than metals as reinforcement - B29K 2995/0089: Impact strength or toughness - Y10S 428/902: High modulus filament or fiber - Y10T 428/24132: including grain, strips, or filamentary elements in different layers or components parallel - Y10T 428/249944: Fiber is precoated - Y10T 428/249945: Carbon or carbonaceous fiber - Y10T 428/249951: Including a free metal or alloy constituent - Y10T 428/30: Self-sustaining carbon mass or layer with impregnant or other layer - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - 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) - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A carbon fiber prepreg comprising a unit layer consisting of carbon fibers and a matrix resin layer, and stranded filaments or single filaments incorporated thereinto. The steel fiber is an Ni plated low-carbon dual-phase steel filament and has a filament diameter of not more than 100 .mu.m, a tensile strength of 300 to 700 kgf/mm.sup.2, and an area reduction at fracture of more than 20%. The carbon fibers and steel filaments are aligned codirectionally, and the steel fiber content of the prepreg relative to the carbon fiber is not more than 10 vol %. Sheets of the carbon fiber prepreg are laminated to form a carbon fiber reinforced composite. ## Claims ### Claim 1 A carbon fiber prepreg comprising a unit layer consisting of unidirectionally aligned carbon fibers and a matrix resin layer, and Stranded filaments individually formed from a plurality of steel filaments twisted together and having a filament diameter of 100 .mu.m or less, a tensile strength of 300 to 700 kgf/mm.sup.2, and an area reduction at fracture of 20% or more which are incorporated into the unit layer in codirectional relation with the carbon fibers so that the steel fiber content of the prepreg relative to the carbon fibers is 10 vol % or less. ### Claim 2 A carbon fiber prepreg comprising a unit layer consisting of unidirectionally aligned carbon fibers and a matrix resin layer, and single filaments of the steel fiber having a filament diameter of 100 .mu.m or less, a tensile strength of 300 to 700 kgf/mm.sup.2, and an area reduction at fracture of 20% or more which are incorporated into the unit layer in codirectional relation with the carbon fibers so that the steel fiber content of the prepreg relative to the carbon fibers is 10 vol % or less in such a way that they are evenly and finely distributed within the unit layer. ### Claim 3 (depends on 1, 2) A carbon fiber reinforced resin composite wherein sheets of the prepreg defined in claim 1 or 2 are laminated together. ### Claim 4 (depends on 1, 2) A carbon fiber prepreg and/or carbon fiber reinforced resin composite as defined in any one of claims 1 or 2, wherein the steel fibers are plated. ### Claim 5 (depends on 1, 2) A carbon fiber prepreg and/or carbon fiber reinforced resin composite as defined in any one of claims 1 or 2, wherein the steel fiber is a low-carbon dual-phase steel filament. ### Claim 6 (depends on 4) A carbon fiber prepreg and/or carbon fiber reinforced resin composite as defined in claim 4, wherein the plating applied to the steel fibers is Ni plating. ### Claim 7 (depends on 3) A carbon fiber prepreg and/or carbon fiber reinforced resin composite as defined in claim 3, wherein the steel fibers are plated. ### Claim 8 (depends on 3) A carbon fiber prepreg and/or carbon fiber reinforced resin composite as defined in claim 3, wherein the steel fiber is a low-carbon dual-phase steel filament. ### Claim 9 (depends on 4) A carbon fiber prepreg and/or carbon fiber reinforced resin composite as defined in claim 4, wherein the steel fiber is a low-carbon dual-phase steel filament. ### Claim 10 (depends on 5) A carbon fiber prepreg and/or carbon fiber reinforced resin composite as defined in claim 5, wherein the plating applied to the steel fibers is Ni plating. ### Claim 11 (depends on 8) A carbon fiber prepreg and/or carbon fiber reinforced resin composite as defined in claim 8, wherein the plating applied to the steel fibers is Ni plating. ### Claim 12 (depends on 9) A carbon fiber prepreg and/or carbon fiber reinforced resin composite as defined in claim 9, wherein the plating applied to the steel fibers is Ni plating.