# US 5,702,816 A · Reinforcing structural rebar and method of making the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,702,816 A - Document ID: US5702816A - Status: Granted - Kind: A - Application number: 08/527,976 - Filed: 1995-09-14 - Granted: 1997-12-30 - Earliest claimed: 1994-06-28 - Assignees: Marshall Industries Composites, Inc. - Inventors: Mark A. Kaiser - Web page: https://patentgrep.com/patent/US5702816A ## CPC - B29C 70/525: {Component parts, details or accessories; Auxiliary operations} - B29C 70/081: {Combinations of fibres of continuous or substantial length and short fibres} - B29C 70/52: Pultrusion, i.e. forming and compressing by continuously pulling through a die - E04C 5/07: Reinforcing elements of material other than metal, e.g. of glass, of plastics, or not exclusively made of metal (metal elements with non-structural coatings E04C5/01) - B29C 35/08: by wave energy or particle radiation {(B29C64/00, B29C71/04 take precedence)} - Y10T 428/1372: Randomly noninterengaged or randomly contacting fibers, filaments, particles, or flakes - Y10T 428/1393: Multilayer [continuous layer] - Y10T 428/237: Noninterengaged fibered material encased [e.g., mat, batt, etc.] - Y10T 428/24083: Nonlinear strands or strand-portions - Y10T 428/249942: Fibers are aligned substantially parallel - Y10T 428/249945: Carbon or carbonaceous fiber - Y10T 428/249946: Glass fiber - Y10T 428/249947: Polymeric fiber - Y10T 428/2905: Plural and with bonded intersections only - Y10T 428/2913: Rod, strand, filament or fiber - Y10T 428/2933: Coated or with bond, impregnation or core - Y10T 428/2936: Wound or wrapped core or coating [i.e., spiral or helical] - Y10T 428/2955: Silicic material in coating - Y10T 428/2962: Silane, silicone or siloxane in coating - 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) - E04C: STRUCTURAL ELEMENTS; BUILDING MATERIALS (for bridges E01D; specially designed for insulation or other protection E04B; elements used as building aids E04G; for mining E21; for tunnels E21D; structural elements with broader range of application than for building engineering F16, particularly F16S) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A structural rebar of the present invention comprises: an inner core formed by pultruding reinforcing fibers of a first reinforcing material through a bath or injection system of a first resin material; and an outer cladding comprising an inner cladding layer and an outer cladding layer. The inner core contains at least about 40 percent by weight reinforcing fibers of the first reinforcing material. The inner cladding layer comprises a second resin material reinforced with reinforcing fibers of a second reinforcing material. The fibers of the second reinforcing material are preferably unidirectional and oriented substantially parallel to the fibers of the first reinforcing material. The outer cladding layer comprises a corrosion-resistant third resin material reinforced with a third reinforcing material. Rebar of this configuration can have sufficient strength, rigidity, and corrosion resistance to be suitable for use in cementitious structural members. ## Claims ### Claim 1 A reinforcing structural rebar comprising: an inner core formed by pultruding reinforcing material through a bath or injection system of a first resin material, the inner core containing at least 40 percent by weight reinforcing fibers of the first reinforcing material; and an outer cladding comprising: an inner cladding layer comprising a second resin material reinforced with unidirectional reinforcing fibers of a second reinforcing material, the fibers of said second reinforcing material being oriented substantially parallel to the fibers of said first reinforcing material; and an outer cladding layer comprising a corrosion-resistant third resin material reinforced with a non-unidirectional third reinforcing material. ### Claim 2 (depends on 1) The reinforcing structural rebar of claim 1, wherein the first resin material is an unsaturated polyester or vinyl ester resin. ### Claim 3 (depends on 1) The reinforcing structural rebar of claim 1, wherein the reinforcing fibers of said first and second materials are selected from the group consisting of fibers of glass, carbon, metal, aromatic polyamides, polybenzimidazoles, aromatic polyimides, polyethylene, nylon, and blends and hybrids thereof. ### Claim 4 (depends on 1) The reinforcing structural rebar of claim 1, wherein the third reinforcing material is an inorganic filler. ### Claim 5 (depends on 1) The reinforcing structural rebar of claim 1, wherein said outer cladding layer further comprises a thickening agent. ### Claim 6 (depends on 5) The reinforcing structural rebar of claim 5, wherein said thickening agent is fumed silica. ### Claim 7 (depends on 1) The reinforcing structural rebar of claim 1, wherein said outer cladding layer has a thickness of between about 0.025 and 0.100 inches. ### Claim 8 (depends on 1) The reinforcing structural rebar of claim 1, wherein each of said second and third reinforcing materials is a vinyl ester modified urethane resin. ### Claim 9 (depends on 8) The reinforcing structural rebar of claim 8, wherein the vinyl ester modified polyurethane is vinyl maleate urethane. ### Claim 10 (depends on 1) The reinforcing structural rebar of claim 1, wherein the first resin material includes a thickening agent. ### Claim 11 (depends on 1) The reinforcing structural rebar of claim 1, wherein said outer cladding includes one of recesses and protrusions configured to improve the gripping of said rebar by a surrounding cementitious material. ### Claim 12 (depends on 1) The reinforcing structural rebar of claim 1, wherein said first, second and third resin materials are selected so that, when said first resin is in a partially cured state and said second and third resins are an essentially uncured state, said rebar can be heated and pressurized such that said first, second and third resin material become substantially cured. ### Claim 13 (depends on 1) The reinforcing structural rebar of claim 1, wherein outer cladding layer includes between about 10 and 50 percent by weight of said inorganic third reinforcing material. ### Claim 14 (depends on 1) The reinforcing structural rebar of claim 1, wherein said inner cladding layer includes between about 30 and 70 percent by weight of said second reinforcing material. ### Claim 15 (depends on 1) The reinforcing structural rebar of claim 1, wherein the second resin material is a thermosetting resin and said second resin is different from said first resin material. ### Claim 16 (depends on 1) The reinforcing structural rebar of claim 1, wherein the radial thickness of the core is greater than the radial thickness of the inner cladding layer. ### Claim 17 (depends on 1) The reinforcing structural rebar of claim 1, wherein the radial thickness of the core is greater than the radial thickness of the outer cladding. ### Claim 18 (depends on 15) The reinforcing structural rebar of claim 15, wherein the third reinforcing material includes material shaped in the form of at least one of spheres and beads.