# US 8,784,526 B2 · Use of multi-layered structure for the manufacture of gas conducts, namely for methane > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,784,526 B2 - Document ID: US8784526B2 - Status: Granted - Kind: B2 - Application number: 13/875,898 - Filed: 2013-05-02 - Published: 2013-09-19 - Granted: 2014-07-22 - Earliest claimed: 2006-11-30 - Assignees: Arkema France - Applicants: Arkema France - Inventors: Benoit Brule; Sylvain Benet - Web page: https://patentgrep.com/patent/US8784526B2 ## CPC - C08L 77/06: Polyamides derived from polyamines and polycarboxylic acids (C08L77/10 takes precedence) - B32B 1/08: Tubular products - B32B 27/08: of synthetic resin - B32B 27/34: comprising polyamides - F16L 11/04: made of rubber or flexible plastics - Y10T 137/0318: Processes - Y10T 428/1393: Multilayer [continuous layer] - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - F16L: PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The present invention relates to the use of a multi-layered structure for the manufacture of gas conducts, namely for methane. The multi-layered structure comprises, from the inside to the outside, the following successive layers: a layer containing at least one polyamide, wherein the polyamide is chosen from PA11, PA12 and an aliphatic polyamide obtained from condensation reaction of an aliphatic diamine having 6 to 18 carbon atoms and an aliphatic diacid having 9 to 18 carbon atoms; optionally, a binding 2 layer; and a layer 3 chosen from an EVOH layer, a layer formed of a mixture of polyamide and a polyolefin with a polyamide matrix, a layer of PA6, Pa6-6, MXD.6 or MXD.10 and a layer of semi-aromatic copolyamide, the layer 3 being intended to be in contact with the transported gas. ## Claims ### Claim 1 A process for transporting natural gas, comprising transporting said natural gas in a multilayer gas duct structure comprising, from the outside towards the inside, the following successive layers: a layer 1 comprising at least one polyamide, that is PA-11, PA-12 or an aliphatic polyamide resulting from the condensation of an aliphatic diamine having from 6 to 18 carbon atoms and an aliphatic diacid having from 9 to 18 carbon atoms; optionally, in contact with layer 1 a tie layer 2; and a layer 3, in contact with layer 1 or, if present, layer 2, which layer 3 is an EVOH layer, a layer formed from a blend of polyamide and a polyolefin with a polyamide matrix, a PA-6, PA-6,6, MXD-6 or MXD-10 layer or a semi-aromatic copolyamide layer, the layer 3 being in contact with the transported natural gas. ### Claim 2 (depends on 1) The process according to claim 1, wherein the layer 1 further comprises at least one additive that is plasticizers, impact modifiers, functionalized or unfunctionalized polyolefins, dyes, pigments, brighteners, antioxidants or UV stabilizers. ### Claim 3 (depends on 1) The process according to claim 1, wherein the multilayer structure further comprises a protective layer 1′, placed on the layer 1. ### Claim 4 (depends on 1) The process according to claim 1, wherein the layer 3 is coated by the following successive layer(s): optionally, a tie layer 4; and a polyamide-based layer 5, the layer 5 being in contact with the gas transported. ### Claim 5 (depends on 4) The process according to claim 4, wherein the layer 5 comprises at least one polyamide that is PA-11, PA-12 or an aliphatic polyamide resulting from the condensation of an aliphatic diamine having from 6 to 18 carbon atoms and an aliphatic diacid having from 9 to 18 carbon atoms. ### Claim 6 (depends on 4) The process according to claim 4, wherein the layer 5 further comprises a functionalized polyolefin and/or an unfunctionalized polyolefin. ### Claim 7 (depends on 1) The process according to claim 1, wherein the multilayer structure is a tube. ### Claim 8 (depends on 7) The process according to claim 7, wherein the tube is smooth. ### Claim 9 (depends on 7) The process according to claim 7, wherein the tube is ringed. ### Claim 10 A process for transporting natural gas, consisting of transporting said natural gas in a multilayer gas duct structure consisting of, from the outside towards the inside, the following successive layers: a layer 1 comprising at least one polyamide, that is PA-11, PA-12 or an aliphatic polyamide resulting from the condensation of an aliphatic diamine having from 6 to 18 carbon atoms and an aliphatic diacid having from 9 to 18 carbon atoms; optionally, in contact with layer 1 a tie layer 2; and a layer 3, in contact with layer 1 or, if present, layer 2, which layer 3 is an EVOH layer, a layer formed from a blend of polyamide and a polyolefin with a polyamide matrix, a PA-6, PA-6,6, MXD-6 or MXD-10 layer or a semi-aromatic copolyamide layer, the layer 3 being in contact with the transported natural gas. ### Claim 11 A process for transporting natural gas, comprising transporting said natural gas in a multilayer gas duct structure comprising, from the outside towards the inside, the following successive layers: a layer 1 comprising at least one polyamide, that is PA-11, PA-12 or an aliphatic polyamide resulting from the condensation of an aliphatic diamine having from 6 to 18 carbon atoms and an aliphatic diacid having from 9 to 18 carbon atoms; in contact with layer 1 a tie layer 2; and a layer 3, in contact with layer 2, which layer 3 is an EVOH layer, a layer formed from a blend of polyamide and a polyolefin with a polyamide matrix, a PA-6, PA-6,6, MXD-6 or MXD-10 layer or a semi-aromatic copolyamide layer, the layer 3 being in contact with the transported natural gas. ### Claim 12 A process for transporting natural gas, comprising transporting said natural gas in a multilayer gas duct structure comprising, from the outside towards the inside, the following successive layers: a layer 1 comprising at least one polyamide, that is PA-11, PA-12 or an aliphatic polyamide resulting from the condensation of an aliphatic diamine having from 6 to 18 carbon atoms and an aliphatic diacid having from 9 to 18 carbon atoms; optionally, in contact with layer 1 a tie layer 2; and a layer 3, in contact with layer 1 or, if present, layer 2, which layer 3 is an EVOH layer, a layer formed from a blend of polyamide and a polyolefin with a polyamide matrix, a PA-6,6, MXD-6 or MXD-10 layer or a semi-aromatic copolyamide layer, the layer 3 being in contact with the transported natural gas. ### Claim 13 (depends on 12) The process according to claim 12, wherein layer 3 is EVOH layer, a layer formed from a blend of polyamide and a polyolefin with a polyamide matrix, a MXD-6 or MXD-10 layer or a semi-aromatic copolyamide layer.