# US 9,520,213 B2 · Materials and methods for insulation of conducting fibres, and insulated products > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,213 B2 - Document ID: US9520213B2 - Status: Granted - Kind: B2 - Application number: 14/346,535 - Filed: 2012-09-27 - Published: 2014-08-21 - Granted: 2016-12-13 - Earliest claimed: 2011-09-27 - Assignees: Cambridge Enterprise Limited - Applicants: Cambridge Enterprise Limited - Inventors: Krzysztof K. K. Koziol; Agnieszka Ewa Lekawa-Raus; Lukasz Kurzepa; Xiaoyu Peng - Web page: https://patentgrep.com/patent/US9520213B2 ## CPC - H01B 13/06: Insulating conductors or cables (H01B13/32 takes precedence) - B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites - B82Y 40/00: Manufacture or treatment of nanostructures - C01B 32/168: After-treatment - H01B 1/04: mainly consisting of carbon-silicon compounds, carbon or silicon - H01B 3/28: natural or synthetic rubbers - H01B 3/441: {from alkenes} - H01B 3/46: silicones - H01B 7/02: Disposition of insulation - B82Y 99/00: Subject matter not provided for in other groups of this subclass - Y10S 977/742: Carbon nanotubes, CNTs - H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K}) - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract An electrical conductor which has an electrically conducting fiber including carbon nanotubes and/or a graphene nanoribbon and a layer of insulating material coated around the electrically conducting fiber. The insulating material substantially does not penetrate the electrically conducting fiber, or penetrates the electrically conducting fiber only to a depth that leaves a continuous conductive path along a remaining part of the electrically conducting fiber. ## Claims ### Claim 1 An electrical conductor comprising: an electrically conducting fibre comprising carbon nanotubes and/or graphene nanoribbon; and a layer of insulating material coated around the electrically conducting fibre, wherein the layer of insulating material is in direct contact with the carbon nanotubes and/or the graphene nanoribbon of the electrically conducting fibre, and wherein the insulating material substantially does not penetrate the electrically conducting fibre, or penetrates the electrically conducting fibre only to a depth that leaves a continuous conductive path along a remaining part of the electrically conducting fibre. ### Claim 2 (depends on 1) The electrical conductor according to claim 1 wherein the electrically conducting fibre comprises at least 75% by weight of carbon nanotubes. ### Claim 3 (depends on 1) The electrical conductor according to claim 1 wherein the insulating material substantially does not penetrate the electrically conducting fibre, or penetrates the electrically conducting fibre only to a depth of not more than 10% of the radius of the fibre. ### Claim 4 (depends on 1) The electrical conductor according to claim 1 wherein the electrically conducting fibre has a diameter of 10 mm or less. ### Claim 5 (depends on 1) The electrical conductor according to claim 1 wherein the electrically conducting fibre has a diameter of 1 mm or less. ### Claim 6 (depends on 1) The electrical conductor according to claim 1 wherein the insulating material substantially does not penetrate the electrically conducting fibre, or penetrates the electrically conducting fibre only to a depth of not more than 5 μm from the surface of the fibre. ### Claim 7 The electrical conductor according to claim lwherein the insulating material comprises a polymer, such as a rubber polymer or low density polyethylene. ### Claim 8 (depends on 1) The electrical conductor according to claim 1 wherein the insulating material comprises a curable silicone polymer, or a siloxane polymer such as polydimethyl siloxane (PDMS). ### Claim 9 (depends on 1) The electrical conductor according to claim 1 having a conductivity of at least 0.7×106 Sm−1. ### Claim 10 An electrical or electronic device comprising one or more electrical conductors comprising: an electrically conducting fibre comprising carbon nanotubes and/or graphene nanoribbon; and a layer of insulating material coated around the electrically conducting fibre, wherein the layer of insulating material is in direct contact with the carbon nanotubes and/or the graphene nanoribbon of the electrically conducting fibre, and wherein the insulating material substantially does not penetrate the electrically conducting fibre, or penetrates the electrically conducting fibre only to a depth that leaves a continuous conductive path along a remaining part of the electrically conducting fibre. ### Claim 11 (depends on 10) The electrical or electronic device according to claim 10 which comprises an electromagnet, and wherein said one or more electrical conductors is used to provide current carrying windings for the electromagnet. ### Claim 12 A method of coating an electrically conducting fibre comprising carbon nanotubes and/or graphene nanoribbon, the method comprising (i) applying flowable insulating material to the electrically conducting fibre to be in direct contact with the carbon nanotubes and/or the graphene nanoribbon of the electrically conducting fibre; and (ii) solidifying said insulating material on the surface of the electrically conducting fibre to coat the fibre with a layer of insulating material, so that the layer of insulating material is in direct contact with carbon nanotubes and/or graphene nanoribbon of the electrically conducting fibre, wherein the insulating material substantially does not penetrate the electrically conducting fibre, or penetrates the electrically conducting fibre only to a depth that leaves a continuous conductive path along a remaining part of the electrically conducting fibre. ### Claim 13 (depends on 12) The method according to claim 12 wherein the viscosity of the flowable insulating material during the application step is adjusted so that the insulating material substantially does not penetrate the electrically conducting fibre, or penetrates the electrically conducting fibre only to a depth that leaves a continuous conductive path along a remaining part of the electrically conducting fibre. ### Claim 14 (depends on 12) The method according to claim 12 wherein during the application step, the flowable insulating material has a dynamic viscosity of at least 200 cP. ### Claim 15 (depends on 12) The method according to claim 12 wherein the flowable insulating material is a molten polymer, and wherein the polymer comprises low density polyethylene, a curable silicone polymer, or a siloxane polymer such as polydimethyl siloxane (PDMS). ### Claim 16 (depends on 12) The method according to claim 12 wherein the flowable insulating material is applied to the fibre from an emulsion of insulating material in water. ### Claim 17 (depends on 16) The method according to claim 16 wherein the emulsion is an emulsion of latex and water. ### Claim 18 (depends on 12) The method according to claim 12 wherein the length of time the fibre is exposed to the flowable insulating material before solidification is adjusted so that the insulating material substantially does not penetrate the fibre, or penetrates the fibre only to a depth that leaves a continuous conductive path along a remaining part of the electrically conducting fibre. ### Claim 19 (depends on 12) The method according to claim 12, wherein the fibre is exposed to the flowable insulating material before solidification for a period of 5 minutes or less. ### Claim 20 (depends on 12) The method according to claim 12 wherein the electrically conducting fibre has a resistance R0 before exposure to the flowable insulating material, and a resistance of R after solidification of the insulating material, and wherein the ratio R/R0 is 1.1 or less.