Thermoplastic multilayer fuel line free of perfluoroor polyfluoroalkyl substances

Abstract

The invention discloses a thermoplastic multi-layer fuel pipeline free of perfluoroalkyl or polyfluoroalkyl substances. The multilayer fuel line includes: a liner layer; a barrier layer circumferentially surrounding the liner layer; and a cover layer circumferentially surrounding the barrier layer. The liner layer includes a polyterephthalamide and has an inner circumferential surface that defines a tubular flow passage extending in an axial direction through the multi-layer fuel line. The inner circumferential surface of the liner layer has a surface resistivity of less than or equal to about 1 x 106 ohms / square at 20 degrees Celsius. The barrier layer includes ethylene vinyl alcohol. The cover layer defines an outer circumferential surface of the multilayer fuel line and includes an aliphatic polyamide.

Description

Technical Field

[0001] The information provided in this section is for the purpose of generally presenting the context of the present disclosure. The work of the presently named inventors, to the extent it is described in this section and in all aspects of this description that may not otherwise be considered prior art at the time of filing, is neither explicitly nor implicitly admitted to be prior art against the present disclosure.

[0002] The present disclosure relates to layered thermoplastic tubing for conveying fuel. Background Art

[0003] Pipes or conduits used to transport liquid fuels are often made of thermoplastic materials and may have a layered structure that provides the conduit with a desired combination of electrical conductivity, low fuel permeability, high chemical and thermal resistance, wear resistance, light weight, mechanical robustness, and flexibility within the desired operating temperature range. Summary of the invention

[0004] A multilayer fuel line is disclosed. The multilayer fuel line includes: a liner layer; a barrier layer that circumferentially surrounds the liner layer; and a cover layer that circumferentially surrounds the barrier layer. The liner layer has an inner circumferential surface that defines a tubular flowthrough channel extending through the multilayer fuel line in an axial direction. The liner layer includes polyterephthalamide. The inner circumferential surface of the liner layer has a flow rate of less than or equal to about 1 x 10 6 The barrier layer comprises ethylene vinyl alcohol. The cover layer defines an outer circumferential surface of the multilayer fuel line. The cover layer comprises an aliphatic polyamide.

[0005] In various aspects, the liner layer can include poly(nonamethyleneterephthalamide).

[0006] The liner layer can be substantially free of esters and amides having a molecular weight of less than or equal to about 2000.

[0007] The liner layer may include a continuous matrix phase and a dispersed phase distributed throughout the continuous matrix phase. The continuous matrix phase may include polyterephthalamide, and the dispersed phase may include a conductive agent.

[0008] In various aspects, the conductive agent can include carbon.

[0009] The continuous matrix phase may comprise greater than or equal to about 80% to less than or equal to about 99.8% by weight of the liner layer. The conductive agent may comprise greater than or equal to about 0.2% to less than or equal to about 20% by weight of the liner layer.

[0010] The liner layer may include a conductive inner layer and an electrically insulating outer layer circumferentially surrounding the inner layer. The conductive inner layer may define an inner circumferential surface of the liner layer and may include a continuous matrix phase including polyterephthalamide and a dispersed phase including a conductive agent. The electrically insulating outer layer may include polyterephthalamide and may have a thermal conductivity greater than 1 x 10 6 Surface resistivity in ohms / square.

[0011] The multilayer fuel line may further include an intermediate layer circumferentially surrounding the liner layer and disposed between the liner layer and the barrier layer. The intermediate layer may include an aliphatic polyamide.

[0012] In various aspects, the intermediate layer can include poly(dodecano-12-lactam).

[0013] The intermediate layer may be physically and chemically bonded directly to the liner layer without the use of an adhesive.

[0014] The barrier layer may create a seal around the tubular flow-through passage, thereby preventing fuel vapor from permeating through the multi-layer fuel line and escaping to the external ambient environment.

[0015] In various aspects, the cover layer can include poly(dodecane-12-lactam), poly(hexamethylene dodecanediamide), or a combination thereof.

[0016] The multilayer fuel line may further include: a first adhesive layer disposed between the liner layer and the barrier layer, the first adhesive layer physically bonding the barrier layer to the liner layer; and a second adhesive layer disposed between the barrier layer and the cover layer, the second adhesive layer physically bonding the cover layer to the barrier layer. Each of the first adhesive layer and the second adhesive layer may include a thermoplastic polymer.

[0017] The multi-layer fuel line may be substantially free of perfluoroalkyl substances, polyfluoroalkyl substances, and combinations thereof.

[0018] The multi-layer fuel line may be configured to withstand temperatures within a range of greater than or equal to approximately -40 degrees Celsius to less than or equal to approximately 130 degrees Celsius.

[0019] A multilayer fuel line according to one or more embodiments of the present disclosure includes: a liner layer; an intermediate layer that circumferentially surrounds the liner layer; a barrier layer that circumferentially surrounds the intermediate layer; and a cover layer that circumferentially surrounds the barrier layer. The liner layer has an inner circumferential surface that defines a tubular flow-through channel extending in an axial direction through the multilayer fuel line. The intermediate layer includes an aliphatic polyamide. The barrier layer includes ethylene vinyl alcohol. The cover layer defines the outer circumferential surface of the multilayer fuel line and includes an aliphatic polyamide. The liner layer has a composite structure that includes a continuous matrix phase and a dispersed phase distributed throughout the continuous matrix phase. The continuous matrix phase includes poly(nonamethylene terephthalamide), and the dispersed phase includes a conductive agent. The conductive agent provides a conductive agent less than or equal to about 1 x 10 6 Surface resistivity in ohms / square.

[0020] The poly(nonane terephthalamide) of the liner layer may provide chemical resistance to volatile liquid fuels and low oligomer extraction to the inner circumferential surface of the liner layer.

[0021] The barrier layer may create a seal that circumferentially surrounds the tubular flow-through passage and prevents fuel vapor from permeating through the multi-layer fuel line and escaping to the external ambient environment.

[0022] The intermediate layer, barrier layer, and cover layer may be electrically insulating and may have a thermal conductivity greater than 1 x 10 6 Surface resistivity in ohms / square.

[0023] The multi-layer fuel line may be substantially free of perfluoroalkyl substances, polyfluoroalkyl substances, and combinations thereof.

[0024] The multi-layer fuel line may be configured to withstand temperatures within a range of greater than or equal to approximately -40 degrees Celsius to less than or equal to approximately 130 degrees Celsius.

[0025] The present invention also discloses the following technical solution:

[0026] Solution 1. A multi-layer fuel pipeline, comprising:

[0027] A liner layer having an inner circumferential surface defining a tubular flow-through passage extending in an axial direction through the multilayer fuel line, the liner layer comprising polyterephthalamide, the inner circumferential surface of the liner layer having a thermal conductivity of less than or equal to about 1 x 10 6 Surface resistivity in ohms / square;

[0028] a barrier layer circumferentially surrounding the liner layer, the barrier layer comprising ethylene vinyl alcohol; and

[0029] A cover layer circumferentially surrounds the barrier layer and defines an outer circumferential surface of the multi-layer fuel line, the cover layer comprising an aliphatic polyamide.

[0030] Option 2. The multilayer fuel line according to Option 1, wherein the liner layer comprises poly(nonane terephthalamide).

[0031] Option 3. A multilayer fuel pipeline according to Option 1, wherein the lining layer is substantially free of esters and amides having a molecular weight of less than or equal to about 2000.

[0032] Option 4. The multi-layer fuel pipeline according to Option 1, wherein the liner layer comprises:

[0033] a continuous matrix phase; and

[0034] a dispersed phase distributed throughout the continuous matrix phase,

[0035] The continuous matrix phase includes the polyterephthalamide, and the dispersed phase includes a conductive agent.

[0036] Option 5. A multilayer fuel pipeline according to Option 4, wherein the conductive agent includes carbon.

[0037] Option 6. A multilayer fuel pipeline according to Option 4, wherein the continuous matrix phase accounts for greater than or equal to about 80% to less than or equal to about 99.8% by weight of the lining layer, and wherein the conductive agent accounts for greater than or equal to about 0.2% to less than or equal to about 20% by weight of the lining layer.

[0038] Option 7. The multilayer fuel pipeline according to Option 1, wherein the liner layer comprises:

[0039] a conductive inner layer defining the inner circumferential surface of the liner layer and comprising a continuous matrix phase comprising polyterephthalamide and a dispersed phase comprising a conductive agent; and

[0040] An electrically insulating outer layer circumferentially surrounding the inner layer, the electrically insulating outer layer comprising polyterephthalamide and having a thermal conductivity greater than 1 x 10 6 Surface resistivity in ohms / square.

[0041] Solution 8. The multi-layer fuel pipeline according to Solution 1 further comprises:

[0042] An intermediate layer circumferentially surrounds the liner layer and is disposed between the liner layer and the barrier layer, the intermediate layer comprising an aliphatic polyamide.

[0043] Option 9. The multilayer fuel line according to Option 8, wherein the intermediate layer comprises poly(dodecane-12-lactam).

[0044] Embodiment 10. The multilayer fuel line of Embodiment 8, wherein the intermediate layer is physically and chemically bonded directly to the liner layer without the use of an adhesive.

[0045] Embodiment 11. The multi-layer fuel line of Embodiment 1, wherein the barrier layer creates a seal around the tubular flow-through channel, thereby preventing fuel vapor from permeating through the multi-layer fuel line and escaping to the external ambient environment.

[0046] Option 12. The multilayer fuel line according to Option 1, wherein the covering layer comprises poly(dodecane-12-lactam), poly(hexamethylene dodecanediamide), or a combination thereof.

[0047] Option 13. The multi-layer fuel pipeline according to Option 1, wherein the multi-layer fuel pipeline is substantially free of perfluoroalkyl substances, polyfluoroalkyl substances, and combinations thereof.

[0048] Solution 14. The multi-layer fuel pipeline according to Solution 1, further comprising:

[0049] a first adhesive layer disposed between the liner layer and the barrier layer, the first adhesive layer physically bonding the barrier layer to the liner layer; and

[0050] a second adhesive layer disposed between the barrier layer and the cover layer, the second adhesive layer physically bonding the cover layer to the barrier layer,

[0051] Wherein each of the first adhesive layer and the second adhesive layer comprises a thermoplastic polymer.

[0052] Option 15. A multi-layer fuel pipeline according to Option 1, wherein the multi-layer fuel pipeline is configured to withstand a temperature in a range of greater than or equal to approximately -40 degrees Celsius to less than or equal to approximately 130 degrees Celsius.

[0053] Solution 16. A multi-layer fuel pipeline, comprising:

[0054] a liner layer having an inner circumferential surface defining a tubular flow-through passage extending in an axial direction through the multi-layer fuel line;

[0055] an intermediate layer circumferentially surrounding the liner layer, the intermediate layer comprising an aliphatic polyamide;

[0056] a barrier layer circumferentially surrounding the intermediate layer, the barrier layer comprising ethylene vinyl alcohol; and

[0057] a cover layer circumferentially surrounding the barrier layer and defining an outer circumferential surface of the multilayer fuel line, the cover layer comprising an aliphatic polyamide,

[0058] The lining layer has a composite structure, which includes a continuous matrix phase and a dispersed phase distributed throughout the continuous matrix phase.

[0059] wherein the continuous matrix phase comprises poly(nonane terephthalamide), and the dispersed phase comprises a conductive agent, and

[0060] The conductive agent provides the inner circumferential surface of the lining layer with a conductivity less than or equal to about 1 x 10 6 Surface resistivity in ohms / square.

[0061] Embodiment 17. The multilayer fuel line of Embodiment 16, wherein the poly(nonane terephthalamide) of the liner layer provides chemical resistance to volatile liquid fuels and low oligomer extraction to the inner circumferential surface of the liner layer.

[0062] Embodiment 18. A multi-layer fuel line according to Embodiment 16, wherein the barrier layer creates a seal that circumferentially surrounds the tubular flow-through channel and prevents fuel vapor from permeating through the multi-layer fuel line and escaping to the external ambient environment.

[0063] Embodiment 19. The multilayer fuel pipeline according to embodiment 16, wherein the intermediate layer, the barrier layer and the cover layer are electrically insulating and have a thermal conductivity greater than 1 x 10 6 Surface resistivity in ohms / square.

[0064] Option 20. A multilayer fuel pipeline according to Option 16, wherein the multilayer fuel pipeline is substantially free of perfluoroalkyl substances, polyfluoroalkyl substances and combinations thereof, and wherein the multilayer fuel pipeline is configured to withstand temperatures in a range of greater than or equal to approximately -40 degrees Celsius to less than or equal to approximately 130 degrees Celsius.

[0065] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and accompanying drawings.The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The present disclosure will become more fully understood from the detailed description and accompanying drawings, in which:

[0067] Figure 1 is a schematic cross-sectional view of a multi-layer fuel line according to one or more embodiments of the present disclosure.

[0068] Figure 2 is a schematic cross-sectional view of a multi-layer fuel line according to another embodiment of the present disclosure.

[0069] In the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0070] A multilayer fuel line according to the present disclosure includes a laminate of thermoplastic polymer layers including an electrically conductive polyterephthalamide liner layer. The polyterephthalamide liner layer provides the multilayer fuel line with low fuel permeability, high chemical and heat resistance over a wide operating temperature range, high strength, dimensional stability, low oligomer extraction into the fuel, and electrical conductivity without the use of per- or polyfluoroalkyl substances (PFAS), such as perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), polytetrafluoroethylene (PTFE), and combinations thereof. The polyterephthalamide liner layer can be used in conjunction with an ethylene vinyl alcohol barrier layer and an aliphatic polyamide cover layer to provide a lightweight multilayer fuel line that exhibits excellent chemical, thermal, and mechanical properties at a relatively low cost compared to multilayer fuel lines that rely on PFAS for adequate chemical and heat resistance.

[0071] Reference now Figure 1 The multilayer fuel line 10 has an outer circumferential surface 12 and an inner circumferential surface 14, which defines a tubular flow-through channel 16 extending therethrough in an axial direction. The multilayer fuel line 10 includes a liner layer 18, an optional intermediate layer 20, a barrier layer 22, a cover layer 24, and an optional first adhesive layer 26 and a second adhesive layer 28. The multilayer fuel line 10 can be used to transport or carry liquid fuels, vapor fuels, or a combination thereof. For example, the multilayer fuel line 10 can be used to transport or carry volatile liquid fuels and / or heavy liquid fuels (e.g., diesel fuel). Examples of volatile liquid fuels include gasoline and / or fatty alcohols (e.g., methanol, ethanol, propanol, and / or butanol). In various aspects, the multilayer fuel line 10 can be used in a motor vehicle and can have an operating temperature range from about -40 degrees Celsius (°C) to about 130°C. Multi-layer fuel line 10 may have a thickness of greater than or equal to approximately 1 millimeter (mm) to less than or equal to approximately 5 mm, the thickness being defined between outer circumferential surface 12 and inner circumferential surface 14 .

[0072] The liner layer 18 is the innermost layer of the multilayer fuel pipeline 10 and is configured to be conductive and to create a physical barrier that prevents the fuel flowing in the tubular through-flow channel 16 from penetrating, permeating or decomposing the multilayer fuel pipeline 10. The liner layer 18 has an inner surface 30 and an opposite outer surface 32, wherein the inner surface 30 defines the inner circumferential surface 14 of the multilayer fuel pipeline 10. The liner layer 18 has a composite structure that includes a continuous matrix phase and a dispersed phase distributed throughout the continuous matrix phase. The continuous matrix phase may account for greater than or equal to about 80%, optionally about 90%, or optionally about 95% to less than or equal to about 99.8%, optionally about 99%, or optionally about 97% of the liner layer 18 by weight. The dispersed phase may account for greater than or equal to about 0.2%, optionally about 1%, or optionally about 3% to less than or equal to about 20%, optionally about 10%, or optionally about 5% of the liner layer 18 by weight.

[0073] The continuous matrix phase includes polyterephthalamide. In various aspects, the continuous matrix phase can be substantially composed of polyterephthalamide or composed of polyterephthalamide. Polyterephthalamide is a partially aromatic, partially crystalline polyamide. Polyterephthalamide provides excellent heat resistance and chemical resistance, strength, wear resistance and abrasion resistance, and good processability for extrusion and injection molding applications to the liner layer 18. In particular, polyterephthalamide provides high chemical resistance to fuel to the liner layer 18, and has low oligomer extraction or leaching from oligomers when in contact with fuel (especially at high operating temperatures). Extraction or leaching of oligomers from fuel system components (e.g., fuel lines) can cause contamination of fuel and / or blockage of fuel system components. In various aspects, the liner layer 18 may include poly (nonane terephthalamide) (also referred to as PA9T). The polyterephthalamide may comprise greater than or equal to about 80%, alternatively about 90%, or alternatively about 95% to less than or equal to about 99.8%, alternatively about 99%, or alternatively about 97% by weight of the liner layer 18 .

[0074] The dispersed phase includes a conductive agent. The conductive agent is distributed throughout at least a portion of the liner layer 18 and provides the liner layer 18 with a desired conductivity. For example, the conductive agent can provide the liner layer 18 with a conductivity of less than or equal to about 1×10 6 Ohm / sq or alternatively less than or equal to about 1 x 10 5Ohm / sq. The conductive agent may be substantially uniformly distributed throughout the continuous matrix phase, or the concentration of the conductive agent may vary within the composite structure of the liner layer 18. For example, in various aspects, the concentration of the conductive agent may be relatively high in a region of the liner layer 18 disposed along the inner circumferential surface 14 of the multilayer hose 10, and may be relatively low in a region of the liner layer 18 disposed along the outer surface 32 of the liner layer 18. The conductive agent may include particles of a carbon-based material, a conductive polymer, or a combination thereof. Examples of conductive carbon-based materials include carbon black (e.g., acetylene black), graphite, graphene (e.g., graphene nanoplatelets), carbon nanotubes (e.g., single-walled and / or multi-walled carbon nanotubes), carbon fibers (e.g., carbon nanofibers), and / or Examples of conductive polymers include polyaniline, polythiophene, polyacetylene, and / or polypyrrole. The conductive agent may comprise greater than or equal to about 0.2%, optionally about 1%, or optionally about 3% to less than or equal to about 20%, optionally about 10%, or optionally about 5% by weight of the liner layer 18.

[0075] The liner layer 18 may be substantially free of additives and residual monomers and / or oligomers having a molecular weight of less than or equal to about 2000, alternatively about 1000, or alternatively about 100. Low molecular weight additives are often included in polymer materials (e.g., polyamides) to provide the material with desired processing characteristics and / or low temperature properties (e.g., impact strength). Examples of such additives include antioxidants (e.g., tris(2,4-di-tert-butylphenyl) phosphite), surfactants, slip agents, plasticizers (e.g., esters and / or amides), acid scavengers, crosslinking agents, and lubricants. For example, the liner layer 18 may be substantially free of ester plasticizers and amide plasticizers having a molecular weight of less than or equal to about 2000, alternatively about 1000, or alternatively about 100. Specific examples of ester plasticizers include phthalates (phthalates, such as dibutyl phthalate and / or dioctyl phthalate), fatty acid esters, polyol esters, phosphate esters, trimellitates (trimellitates), and hydroxybenzoates. Specific examples of amide plasticizers include sulfonamides, such as benzenesulfonamide (e.g., N-butylbenzenesulfonamide) and / or toluenesulfonamide. In various aspects, the liner layer 18 may be substantially free of amide monomers and / or oligomers having a molecular weight of less than or equal to about 2000, optionally about 1000, or optionally about 100.

[0076] The liner layer 18 may be substantially free of perfluoroalkyl substances, polyfluoroalkyl substances, and combinations thereof. For example, the liner layer 18 may be substantially free of PTFE. The liner layer 18 may have a thickness of greater than or equal to about 0.1 mm to less than or equal to about 1 mm, which is defined between the inner surface 30 and the outer surface 32.

[0077] An optional intermediate layer 20 circumferentially surrounds the liner layer 18 and is disposed between the liner layer 18 and the barrier layer 22. The intermediate layer 20 may be electrically insulating and configured to provide stiffness to the multilayer fuel line 10 and / or ensure good bonding between the liner layer 18 and the barrier layer 22. The intermediate layer 20 includes an aliphatic polyamide. For example, the intermediate layer 20 may include poly(dodecane-12-lactam) (also known as PA12). The intermediate layer 20 may be directly physically and chemically bonded to the liner layer 18 without the use of an adhesive.

[0078] Barrier layer 22 circumferentially surrounds liner layer 18 and is disposed between liner layer 18 and cover layer 24. In aspects where multi-layer fuel line 10 includes intermediate layer 20, barrier layer 22 is disposed between intermediate layer 20 and cover layer 24. Barrier layer 22 may be electrically insulating and configured to create a seal around tubular flow-through passage 16, thereby preventing gas and / or vapor from permeating through multi-layer fuel line 10 and escaping to the external ambient environment. Barrier layer 22 may include ethylene vinyl alcohol (EVOH).

[0079] Cover layer 24 is the outermost layer of multi-layer fuel line 10 and circumferentially surrounds barrier layer 22. Cover layer 24 may be electrically insulating and configured to provide flexibility, durability, and resistance to abrasion, wear, impact, and weathering (e.g., resistance to ozone, UV, and hydrolysis) to multi-layer fuel line 10. Cover layer 24 includes an aliphatic polyamide. For example, cover layer 24 may include poly(dodecane-12-lactam) (also known as PA12), poly(hexamethylene dodecanediamide) (also known as nylon 6,12 or PA612), or a combination thereof.

[0080] The optional first adhesive layer 26 is disposed between the liner layer 18 and the barrier layer 22 and provides a strong physical bond therebetween. In aspects where the multi-layer fuel line 10 includes the intermediate layer 20, the first adhesive layer 26 is disposed between the intermediate layer 20 and the barrier layer 22 and provides a strong physical bond therebetween. The first adhesive layer 26 includes a polyolefin resin. The specific composition of the polyolefin resin can be selected based on the composition of the liner layer 18 and the barrier layer 22 and / or the composition of the intermediate layer 20 and the barrier layer 22.

[0081] The optional second adhesive layer 28 is disposed between the barrier layer 22 and the cover layer 24 and provides a strong physical bond therebetween. The second adhesive layer 28 may include a thermoplastic polymer, such as a polyolefin resin. The specific composition of the thermoplastic polymer may be selected based on the composition of the barrier layer 22 and the cover layer 24.

[0082] In various aspects, the multi-layer fuel line 10 may be comprised of the liner layer 18, the barrier layer 22, and the cover layer 24, and may not have any additional layers below the liner layer 18, overlying the cover layer 24, disposed between the liner layer 18 and the barrier layer 22, or disposed between the barrier layer 22 and the cover layer 24. In other aspects, the multi-layer fuel line 10 may be comprised of the liner layer 18, the intermediate layer 20, the barrier layer 22, the cover layer 24, and the first and second adhesive layers 26 and 28, and may not have any additional layers below the liner layer 18, overlying the cover layer 24, or disposed between the liner layer 18 and the cover layer 24.

[0083] Figure 2 Another embodiment of a multi-layer fuel line 110 is depicted. Multi-layer fuel line 110 is similar in many respects to multi-layer fuel line 10, and like numbers between the embodiments generally indicate like or corresponding elements in the drawings. Therefore, the description of multi-layer fuel line 10 is incorporated into the description of multi-layer fuel line 110, and the description of the common subject matter of multi-layer fuel line 10 and multi-layer fuel line 110 generally may not be repeated here.

[0084] The multi-layer fuel line 110 includes a liner layer 118, an optional intermediate layer 20, a vapor barrier layer 22, a cover layer 24, and an optional first adhesive layer 26 and a second adhesive layer 28. The liner layer 118 is the innermost layer of the multi-layer fuel line 110 and has an inner surface 130 and an opposite outer surface 132, wherein the inner surface 130 defines the inner circumferential surface 14 of the multi-layer fuel line 110. The liner layer 118 has a double-layer structure including an inner layer 134 and an outer layer 136 circumferentially surrounding the inner layer 134. The inner layer 134 of the liner layer 118 defines the inner surface 130 of the liner layer 118 and the inner circumferential surface 14 of the multi-layer fuel line 110. The outer layer 136 defines the outer surface 132 of the liner layer 118. The inner layer 134 is electrically conductive and may have substantially the same chemical composition and physical properties as those of the liner layer 18. On the other hand, outer layer 136 is electrically insulating and can have a composition substantially the same as the composition of the continuous matrix phase of liner layer 18. For example, outer layer 136 can include, consist essentially of, or consist of polyterephthalamide (e.g., poly(nonane terephthalamide)). Outer layer 136 can be substantially free of conductive agents. Outer layer 136 can have a conductivity greater than 1 x 10 6 Ohm / sq or optionally greater than or equal to about 1x 10 14 Surface resistivity in Ohm / sq.

[0085] In various aspects, the multi-layer fuel line 110 may be comprised of the liner layer 118, the barrier layer 22, and the cover layer 24, and may not have any additional layers below the liner layer 118, overlying the cover layer 24, disposed between the liner layer 118 and the barrier layer 22, or disposed between the barrier layer 22 and the cover layer 24. In other aspects, the multi-layer fuel line 110 may be comprised of the liner layer 118, the intermediate layer 20, the barrier layer 22, the cover layer 24, and the first and second adhesive layers 26 and 28, and may not have any additional layers below the liner layer 118, overlying the cover layer 24, or disposed between the liner layer 118 and the cover layer 24.

[0086] The multilayer fuel line 10, 110 can be manufactured via an extrusion process (e.g., a coextrusion process). In an extrusion process, a material having the same composition as one of the layers (e.g., 18, 20, 22, 24) is melted, fed to an extruder, and forced through a die at high temperature and pressure to form one of the layers. In a coextrusion process, a plurality of molten materials having different compositions corresponding to different layers (e.g., 18, 22, and 24) can be fed into separate extruders and then forced through a single die where the molten materials are combined and deposited concentrically and simultaneously around and on top of each other so that the layers adhere to each other and produce the multilayer fuel line 10, 110. Alternatively, one or more of the inner layers (e.g., 18 and / or 22) of the multilayer fuel line 10, 110 can be preformed (e.g., by extrusion), and then one or more of the surrounding layers (e.g., 22 and / or 24) can be formed concentrically on and around the one or more preformed inner layers. In some aspects, multi-layer fuel lines 10, 110 can be manufactured via multiple extrusion and / or coextrusion processes. Prior to extrusion (or coextrusion), the starting materials can be dried to remove residual moisture therefrom.

[0087] During the extrusion process, the thickness of the layers (e.g., 18, 20, 22, 24) may be measured (e.g., by a laser) and controlled or adjusted by controlling or adjusting the extruder settings as the layers are extruded. The multilayer fuel line 10, 110 may be cooled as it exits the extruder and either placed into a roll or cut into desired lengths. Each cut length of multilayer fuel line 10, 110 may be placed in a form to assume a preconfigured shape and heated (e.g., on a conveyor advancing through an oven) to soften the multilayer fuel line 10, 110 and conform to the shape induced by the form. After the formed multilayer fuel line 10, 110 is cooled, a fitting may be press-fit into its open end to form a finished fuel line assembly.

[0088] The foregoing description is merely illustrative in nature and is in no way intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in various forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited, because when studying the drawings, the specification and the following claims, other modifications will become apparent. It should be understood that one or more steps in the method can be performed in different orders (or simultaneously) without changing the principles of the present disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the present disclosure can be implemented and / or combined with it in the features of any one of the other embodiments, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the arrangement of one or more embodiments to each other is still within the scope of the present disclosure.

[0089] The terms used herein are only used for the purpose of describing the exemplary embodiments and are not intended to be restrictive. As used herein, the singular forms "one", "an" and "the" may be intended to also include plural forms unless the context clearly indicates otherwise. The terms "include", "contain", "comprise" and "have" are inclusive, and therefore specify the existence of the stated features, elements, compositions, steps, integers, operations and / or parts, but do not exclude the existence or addition of one or more other features, integers, steps, operations, elements, parts and / or their groups. Although the open-ended terms "include", "contain", "comprise" and "have" will be understood as non-limiting terms for describing and claiming the various embodiments set forth herein, in some aspects, these terms are alternatively understood as more restrictive and limited terms, such as "consisting of..." or "consisting of substantially...". Therefore, for any given embodiment of a narration composition, material, component, element, ingredient, feature, integer, operation and / or process step, the present disclosure also specifically includes an embodiment consisting of or substantially consisting of such a narrated composition, material, component, element, ingredient, feature, integer, operation and / or process step. In the case of “consisting of,” alternative embodiments exclude any additional compositions, materials, components, elements, ingredients, features, integers, operations and / or process steps, while in the case of “consisting essentially of,” any additional compositions, materials, components, elements, ingredients, features, integers, operations and / or process steps that materially affect the basic and novel characteristics are excluded from such embodiments, but any compositions, materials, components, elements, ingredients, features, integers, operations and / or process steps that do not materially affect the basic and novel characteristics may be included in such embodiments.

[0090] Any method steps, processes, and operations described herein should not be construed as necessarily requiring their performance in the order discussed or illustrated, unless specifically identified as an order of performance. It will also be understood that additional or alternative steps may be employed unless otherwise indicated.

[0091] When a part, element, or layer is referred to as being "on," "engaged to," "connected to," or "coupled to" another element or layer, it may be directly on, engaged, connected, or coupled to the other part, element, or layer, or there may be intervening elements or layers. In contrast, when an element is referred to as being "directly on," "directly engaged to," "directly connected to," or "directly coupled to" another element or layer, there may be no intervening elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and / or" includes a combination of one or more of the associated listed items.

[0092] Although the terms first, second, third, etc. can be used herein to describe various steps, elements, components, regions, layers and / or sections, unless otherwise indicated, these steps, elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish a step, element, component, region, layer or section from another step, element, component, region, layer or section. When used in this article, terms such as "first", "second" and other numerical terms do not imply sequence or order unless the context clearly indicates. Therefore, the first step, element, component, region, layer or section discussed below can be referred to as the second step, element, component, region, layer or section, without departing from the teaching of the exemplary embodiment.

[0093] For ease of description, spatial or temporal relative terms (such as "front", "rear", "inside", "outside", "below", "below", "lower", "above", "upper", etc.) may be used herein to describe the relationship of one element or feature to another (some) elements or features as illustrated in the figures. In addition to the orientation depicted in the figures, spatial or temporal relative terms may also be intended to encompass different orientations of a device or system in use or operation.

[0094] Throughout this disclosure, numerical values ​​represent approximate measurements or range limits and encompass slight deviations from given values ​​as well as embodiments having approximately the values ​​mentioned and embodiments having exactly the values ​​mentioned. In addition to the working examples provided at the end of the specific embodiments, all numerical values ​​of parameters (e.g., parameters of amounts or conditions) in this specification will be understood to be modified by the term "about" in all cases, regardless of whether "about" actually appears before the numerical value. In the appended claims, the numerical values ​​of the parameters will be understood to be modified by such terms only when the term "about" appears before the numerical value. "About" indicates that the stated numerical value allows a certain slight imprecision (somewhat close to the exact value; approximately or reasonably close to the value; almost). If the imprecision provided by "about" is not otherwise understood in this ordinary sense in the art, then "about" as used herein at least indicates the variation that may be caused by the common methods of measuring and using such parameters. For example, "about" may include less than or equal to 5%, alternatively less than or equal to 4%, alternatively less than or equal to 3%, alternatively less than or equal to 2%, alternatively less than or equal to 1%, alternatively less than or equal to 0.5%, and in some aspects optionally less than or equal to 0.1%. In addition, the disclosure of ranges includes all values ​​within the entire range and the disclosure of further subdivided ranges, including endpoints and subranges given for these ranges.

[0095] As used herein, the terms "composition" and "material" are used interchangeably to refer generally to a substance that contains at least a preferred chemical constituent, element, or compound, but unless otherwise indicated, it may also include additional elements, compounds, or substances, including trace impurities. A composition or material "based on X" refers generally to a combination or material in which "X" is the single largest component of the composition or material on a weight percent (%) basis. This can include compositions or materials having greater than 50% by weight of X and compositions or materials having less than 50% by weight of X, as long as X is the single largest component of the composition or material based on its total weight. When a composition or material is referred to as being "substantially free" of a substance, the composition or material may include less than 5%, optionally less than 3%, optionally less than 1%, or optionally less than 0.1% of the substance by weight.

[0096] As used herein, the term "metal" may refer to a pure elemental metal or to an alloy of an elemental metal and one or more other metals or nonmetallic elements (referred to as "alloying" elements). Alloying elements may be selected to impart certain desirable properties to the alloy that are not exhibited by the base metal element.

Claims

1. A multi-layer fuel pipeline, comprising: A liner layer having an inner circumferential surface defining a tubular flow-through passage extending in an axial direction through the multilayer fuel line, the liner layer comprising polyterephthalamide, the inner circumferential surface of the liner layer having a thermal conductivity of less than or equal to about 1 x 10 6 Surface resistivity in ohms / square; a barrier layer circumferentially surrounding the liner layer, the barrier layer comprising ethylene vinyl alcohol; and A cover layer circumferentially surrounds the barrier layer and defines an outer circumferential surface of the multi-layer fuel line, the cover layer comprising an aliphatic polyamide.

2. The multi-layer fuel pipeline according to claim 1, wherein: The liner layer includes poly(nonane terephthalamide).

3. The multi-layer fuel pipeline according to claim 1, wherein: The liner layer is substantially free of esters and amides having a molecular weight of less than or equal to about 2,000.

4. The multi-layer fuel pipeline according to claim 1, wherein: The lining layer comprises: a continuous matrix phase; and a dispersed phase distributed throughout the continuous matrix phase, The continuous matrix phase includes the polyterephthalamide, and the dispersed phase includes a conductive agent.

5. The multi-layer fuel pipeline according to claim 4, wherein: The conductive agent includes carbon.

6. The multi-layer fuel pipeline according to claim 4, wherein: The continuous matrix phase comprises greater than or equal to about 80% to less than or equal to about 99.8% by weight of the liner layer, and wherein the conductive agent comprises greater than or equal to about 0.2% to less than or equal to about 20% by weight of the liner layer.

7. The multi-layer fuel pipeline according to claim 1, wherein: The lining layer comprises: a conductive inner layer defining the inner circumferential surface of the liner layer and comprising a continuous matrix phase comprising polyterephthalamide and a dispersed phase comprising a conductive agent; and An electrically insulating outer layer circumferentially surrounding the inner layer, the electrically insulating outer layer comprising polyterephthalamide and having a thermal conductivity greater than 1 x 10 6 Surface resistivity in ohms / square.

8. The multi-layer fuel line of claim 1, further comprising: An intermediate layer circumferentially surrounds the liner layer and is disposed between the liner layer and the barrier layer, the intermediate layer comprising an aliphatic polyamide.

9. The multi-layer fuel pipeline according to claim 8, wherein: The intermediate layer includes poly(dodecane-12-lactam).

10. A multi-layer fuel pipeline comprising: a liner layer having an inner circumferential surface defining a tubular flow-through passage extending in an axial direction through the multi-layer fuel line; an intermediate layer circumferentially surrounding the liner layer, the intermediate layer comprising an aliphatic polyamide; a barrier layer circumferentially surrounding the intermediate layer, the barrier layer comprising ethylene vinyl alcohol; as well as a cover layer circumferentially surrounding the barrier layer and defining an outer circumferential surface of the multilayer fuel line, the cover layer comprising an aliphatic polyamide, The lining layer has a composite structure, which includes a continuous matrix phase and a dispersed phase distributed throughout the continuous matrix phase. wherein the continuous matrix phase comprises poly(nonane terephthalamide), and the dispersed phase comprises a conductive agent, and The conductive agent provides the inner circumferential surface of the lining layer with a conductivity less than or equal to about 1×10 6 Surface resistivity in ohms / square.

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