# US 6,039,085 A · Multi-layer tubing assembly with foamed outer layer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,039,085 A - Document ID: US6039085A - Status: Granted - Kind: A - Application number: 09/314,809 - Filed: 1999-05-19 - Granted: 2000-03-21 - Earliest claimed: 1996-01-29 - Assignees: Bundy Corporation - Inventors: Henry S. Hsich - Web page: https://patentgrep.com/patent/US6039085A ## CPC - F16L 11/04: made of rubber or flexible plastics - B29C 48/022: {characterised by the choice of material} - B29C 48/09: Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels - B29C 48/21: the layers being joined at their surfaces - B29C 48/335: Multiple annular extrusion nozzles in coaxial arrangement, e.g. for making multi-layered tubular articles - B32B 1/08: Tubular products - F16L 9/121: {with three layers} - F16L 9/123: {with four layers} - F16L 9/125: {electrically conducting} - F16L 11/127: electrically conducting - B29C 48/0012: {combined with shaping by internal pressure generated in the material, e.g. foaming} - B29K 2027/06: PVC, i.e. polyvinylchloride - B29K 2027/18: PTFE, i.e. polytetrafluoroethylene {, e.g. ePTFE, i.e. expanded polytetrafluoroethylene} - B29K 2105/04: cellular or porous - B29L 2023/005: {Hoses, i.e. flexible} - F16L 2011/047: {with a diffusion barrier layer} - Y10S 138/01: Adhesive - F16L: PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL - 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 - 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 - B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A multi-layer tubing for use in fluid transport applications. The tubing is suitable for conveying fluids containing hydrocarbons. The tubing comprises an extrudable adhesive layer of multi-phase polymer blends or alloys which is coextruded around a permeation-resistant layer of fluoropolymer. An outer layer of foamed polyamide is coextruded around the adhesive layer. The adhesive layer of polymer blends or alloys has a multi-phase morphology wherein one phase is miscible with the fluoropolymer for forming the permeation-resistant layer and another phase is miscible with the polyamide for forming the foamed outer layer. ## Claims ### Claim 1 A multi-layer tubing assembly comprising: an extruded inner permeation-resistant layer of fluoropolymer; an adhesive layer co-extruded around said inner layer, said adhesive layer is comprised of a polymer alloy having a multi-phase morphology wherein one phase in miscible with fluoropolymer and another phase is miscible with polyamide; and an outer layer of foamed polyamide coextruded around said adhesive layer. ### Claim 2 (depends on 1) A multi-layer tubing assembly as claimed in claim 1 wherein said outer layer of foamed polyamide is formed by mixing blowing agent with polyamide prior to extruding said mixture of blowing agent and polyamide. ### Claim 3 (depends on 2) A multi-layer tubing assembly as claimed in claim 2 wherein said blowing agent is selected from the group consisting of azodicarbonamides, hydrazine derivatives, semi-carbazides, tetrazoles, benzoxazines and mixtures thereof. ### Claim 4 (depends on 2) A multi-layer tubing assembly as claimed in claim 2 wherein said polyamide is selected from the group consisting of nylon 46, nylon 6 and nylon 12. ### Claim 5 (depends on 1) A multi-layer tubing assembly as claimed in claim 1 wherein said inner permeation-resistant layer of fluoropolymer is semi-conductive. ### Claim 6 (depends on 5) A multi-layer tubing assembly as claimed in claim 5 wherein said inner permeation-resistant and semi-conductive layer of fluoropolymer has a surface resistivity in the range of about 10.sup.2 to 10.sup.8 ohm/sq. ### Claim 7 (depends on 5) A multi-layer tubing assembly as claimed in claim 5 wherein said inner permeation-resistant and semi-conductive layer of fluoropolymer comprises 1% to 10% by weight of conductive carbon black. ### Claim 8 A multi-layer tubing assembly comprising: an extruded inner permeation-resistant layer of fluoropolymer; an adhesive layer co-extruded around said inner layer, said adhesive layer is comprised of a polymer alloy having a multi-phase morphology wherein one phase in miscible with fluoropolymer and another phase is miscible with polyamide; an polyamide layer coextruded around said adhesive layer; and an outer layer of foamed polyamide coextruded around said polyamide layer. ### Claim 9 (depends on 8) A multi-layer tubing assembly as claimed in claim 8 wherein said outer layer of foamed polyamide is formed by mixing blowing agent with polyamide prior to extruding said mixture of blowing agent and polyamide. ### Claim 10 (depends on 9) A multi-layer tubing assembly as claimed in claim 9 wherein said blowing agent is selected from the group consisting of azodicarbonamides, hydrazine derivatives, semi-carbazides, tetrazoles, benzoxazines and mixtures thereof. ### Claim 11 (depends on 9) A multi-layer tubing assembly as claimed in claim 9 wherein said polyamide is selected from the group consisting of nylon 46, nylon 6 and nylon 12. ### Claim 12 (depends on 8) A multi-layer tubing assembly as claimed in claim 8 wherein said inner permeation-resistant layer of fluoropolymer is semi-conductive. ### Claim 13 (depends on 12) A multi-layer tubing assembly as claimed in claim 12 wherein said inner permeation-resistant and semi-conductive layer of fluoropolymer has a surface resistivity in the range of about 10.sup.2 to 10.sup.8 ohm/sq. ### Claim 14 (depends on 12) A multi-layer tubing assembly as claimed in claim 12 wherein said inner permeation-resistant and semi-conductive layer of fluoropolymer comprises 1% to 10% by weight of conductive carbon black. ### Claim 15 A multi-layer tubing assembly comprising: an extruded innermost semi-conductive layer of fluoropolymer; an inner permeation-resistant layer of fluoropolymer coextruded around said innermost layer; an adhesive layer co-extruded around said inner layer, said adhesive layer is comprised of a polymer alloy having a multi-phase morphology wherein one phase in miscible with fluoropolymer and another phase is miscible with polyamide; and an outer layer of foamed polyamide coextruded around said adhesive layer. ### Claim 16 (depends on 15) A multi-layer tubing assembly as claimed in claim 15 wherein said outer layer of foamed polyamide is formed by mixing blowing agent with polyamide prior to extruding said mixture of blowing agent and polyamide. ### Claim 17 (depends on 16) A multi-layer tubing assembly as claimed in claim 16 wherein said blowing agent is selected from the group consisting of azodicarbonamides, hydrazine derivatives, semi-carbazides, tetrazoles, benzoxazines and mixtures thereof. ### Claim 18 (depends on 16) A multi-layer tubing assembly as claimed in claim 16 wherein said polyamide is selected from the group consisting of nylon 46, nylon 6 and nylon 12. ### Claim 19 (depends on 15) A multi-layer tubing assembly as claimed in claim 15 wherein said innermost semi-conductive layer of fluoropolymer has a surface resistivity in the range of about 10.sup.2 to 10.sup.8 ohm/sq. ### Claim 20 (depends on 15) A multi-layer tubing assembly as claimed in claim 15 wherein said innermost semi-conductive layer of fluoropolymer comprises 1% to 10% by weight of conductive carbon black. ### Claim 21 A multi-layer tubing assembly comprising: an extruded innermost semi-conductive layer of fluoropolymer; an inner permeation-resistant layer of fluoropolymer coextruded around said innermost layer; an adhesive layer co-extruded around said inner layer, said adhesive layer is comprised of a polymer alloy having a multi-phase morphology wherein one phase in miscible with fluoropolymer and another phase is miscible with polyamide; an polyamide layer coextruded around said adhesive layer; and an outer layer of foamed polyamide coextruded around said polyamide layer. ### Claim 22 (depends on 21) A multi-layer tubing assembly as claimed in claim 21 wherein said outer layer of foamed polyamide is formed by mixing blowing agent with polyamide prior to extruding said mixture of blowing agent and polyamide. ### Claim 23 (depends on 22) A multi-layer tubing assembly as claimed in claim 22 wherein said blowing agent is selected from the group consisting of azodicarbonamides, hydrazine derivatives, semi-carbazides, tetrazoles, benzoxazines and mixtures thereof. ### Claim 24 (depends on 22) A multi-layer tubing assembly as claimed in claim 22 wherein said polyamide is selected from the group consisting of nylon 46, nylon 6 and nylon 12. ### Claim 25 (depends on 21) A multi-layer tubing assembly as claimed in claim 21 wherein said innermost semi-conductive layer of fluoropolymer has a surface resistivity in the range of about 10.sup.2 to 10.sup.8 ohm/sq. ### Claim 26 (depends on 21) A multi-layer tubing assembly as claimed in claim 21 wherein said innermost semi-conductive layer of fluoropolymer comprises 1% to 10% by weight of conductive carbon black.