Annulated tubular structure intended for transporting fuel into tank

Abstract

To provide a tube to be located in a fuel tank of a vehicle, the tube having only a small amount of extractables therefrom into a fuel.SOLUTION: A partially annulated flexible tubular structure located at least partially inside a gasoline tank includes at least one layer (1) including a composition including: a. 39-100 wt.%, in particular 41-100 wt.%, of at least one aliphatic polyamide of formula W / Z; b. 0-4 wt.%, preferably 0-2 wt.%, of at least one plasticizer; c. 0-20 wt.% of at least one impact modifier; and d. 0-37 wt.% of at least one additive; where the sum of a.+b.+c.+d. is equal to 100% of the total weight of the composition; excluding a fuel transport structure running from the tank to a motor of the vehicle.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a part-annular flexible tubular structure for transporting fuel, in particular gasoline or diesel, especially gasoline, in the tank of a motor vehicle.

[0002] More particularly, the present invention relates to a single or multi-layer tubular structure that can be at least partially disposed within a fuel tank and at least partially submerged within the vehicle tank.

[0003] Said single or multi-layer tubular structure is therefore intended to be at least partially inside a fuel tank and is capable of being at least partially submerged within the tank of a vehicle. [Background technology]

[0004] The fuels currently used in automobiles increasingly contain corrosive compounds such as methanol or ethanol.

[0005] Alcoholic and other compounds present in the transported fuel cause dissolution and diffusion of monomers and oligomers originating from chemicals, especially tubing (which is typically made from aliphatic materials such as aliphatic polyamides like PA11 or PA12) that come into contact with the gasoline.

[0006] Automobile manufacturers are placing increasing demands on the amount of extractables, such as dissolved monomers / oligomers, in gasoline that can clog fuel injectors.

[0007] According to US Patent No. 5,076,329, a layer of PA6 as an inner layer makes it possible to at least partially eliminate the problem of excessive extractables, which would occur if PA12 was used in the inner layer of a gasoline pipe containing five layers. The use of a five-layer system makes it possible to obtain a tube with the impact resistance of PA12 at a low level of monomers / oligomers.

[0008] Nevertheless, according to document WO 94 / 09303, these properties are not obtained with tubes having fewer than five layers.

[0009] This document therefore recommends the use of a partially annular two- or three-layer tube, comprising an outer layer that may be made of PA11 or PA12, and an inner layer that is not made of polyamide but is chosen from fluorinated compounds such as PVDF, for a two-layer structure. A tie layer, in particular made of PVDF, is then introduced between the outer and inner layers in the context of a three-layer structure.

[0010] However, these tubes have an operating temperature of -40°C to 150°C and are used in vehicle motors.

[0011] EP 1039199 discloses a part-annular tube for use in transporting gasoline comprising at least two layers: an outer layer of polyamide and an inner layer of tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride (THV).

[0012] Nevertheless, the document specifies that the outer layer protects the tube from impacts caused by stones, for example, when the car is moving, and that the resin preferably has a certain resistance to elongation and impacts, which means that the use of the tube is intended to transport gasoline from a tank or into a motor. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] U.S. Patent No. 5,076,329 [Patent Document 2] International Publication No. 94 / 09303 [Patent Document 3] European Patent Application Publication No. 1039199 Summary of the Invention [Problem to be solved by the invention]

[0014] Therefore, for use of this tubing in a vehicle tank, it is necessary to have available tubing that can be at least partially submerged in the vehicle's fuel, but that has an amount of extractables that is less than that of previous background art tubing and meets the manufacturer's requirements. [Means for solving the problem]

[0015] This has been solved by the partially annular flexible structure of the present invention.

[0016] The present invention therefore relates to a partly annular flexible tubular structure to be placed at least partly inside a fuel tank, in particular a petrol or diesel tank, in particular a petrol tank, of a vehicle, said structure being at least partly submersible in said tank and intended to transport said fuel to said tank, said tubular structure comprising: a. 39% to 100% by weight, in particular 41% to 100% by weight, of at least one aliphatic polyamide of the formula W / Z, (however, W is at least one of C6 to C 18 Lactams, preferably C7-C 13 Lactam or at least one C6-C 18 Aminocarboxylic acids, preferably C7-C 13 aliphatic repeat units XY resulting from the polycondensation of aminocarboxylic acids or having an average number of carbon atoms per indicated nitrogen atom ranging from 6 to 18, preferably from 7 to 13, - At least one C6-C 18 diamine X, wherein the diamine is selected from linear or branched aliphatic diamines or mixtures thereof, and - At least one C6-C 18 Aliphatic dicarboxylic acid Y, XY is an aliphatic repeating unit obtained by polycondensation of Z is at least one optional polyamide repeat unit, Z can be present in an amount of up to 30% by weight relative to the total weight W / Z, preferably up to 15% by weight relative to the total weight W / Z. b. 0-4% by weight, preferably 0-2% of at least one plasticizer; c. 0% to 20% of at least one impact modifier; d. 0-37 wt. % of at least one additive; Including, The sum of a.+b.+c.+d. is equal to 100%. at least one layer (1) comprising a composition, This relates to tubular structures, excluding fuel transport structures extending from the tank to the vehicle motor.

[0017] In other words, the structure is intended to be located at least partially inside the fuel tank.

[0018] The inventors have therefore found that a tubular structure comprising a layer comprising the particular composition defined above makes it possible to significantly reduce the amount of extractables, in particular "solubles", and thus meet the requirements of extractables testing by automobile manufacturers.

[0019] The term "flexible" means that the tubular structure's ability to deform and stretch allows it to form relatively small angles, thus allowing it to fit into the limited space bounded by the fuel tank.

[0020] The expression "located at least partially inside the tank" preferably means that more than 70%, more preferably more than 90%, even more preferably more than 95% and in particular 100% of the total length of the tube is located inside the tank, and that part of the tube can leave the tank, in particular by means of a coupling device, to accommodate a tube for transporting gasoline between the tank and the motor.

[0021] In one embodiment, the tubular structure comprises: a. 39% to 100% by weight, in particular 41% to 100% by weight, of at least one aliphatic polyamide of the formula W / Z, (however, W is at least one of C6 to C 18 Lactams, preferably C7-C 13 Lactam or at least one C6-C 18 Aminocarboxylic acids, preferably C7-C 13 aliphatic repeat units XY resulting from the polycondensation of aminocarboxylic acids or having an average number of carbon atoms per indicated nitrogen atom ranging from 6 to 18, preferably from 7 to 13, - At least one C6-C 18 diamine X, wherein the diamine is selected from linear or branched aliphatic diamines or mixtures thereof, and - At least one C6-C 18 Aliphatic dicarboxylic acid Y, and XY is an aliphatic repeat unit obtained from the polycondensation of Z is at least one optional polyamide repeat unit, Z can be present in an amount of up to 30% by weight relative to the total weight W / Z, preferably up to 15% by weight relative to the total weight W / Z. b. 0-4% by weight, preferably 0-2% of at least one plasticizer; c. 0% to 20% by weight of at least one impact modifier; d. 0-37 wt. % of at least one additive; It consists of the sum of a.+b.+c.+d. is equal to 100% of the total weight of the composition; at least one layer (1) comprising a composition, excluding fuel transport structure extending from said tank to said vehicle motor.

[0022] Thus, no components other than components a, b, c, and d are present in the composition, and the sum of components a, b, c, and d equals 100% by weight.

[0023] In another embodiment, the tubular structure comprises: a. 39% to 100% by weight, in particular 41% to 100% by weight, of at least one aliphatic polyamide of the formula W / Z, (however, W is at least one of C6 to C 18 Lactams, preferably C7-C 13 Lactam or at least one C6-C 18 Aminocarboxylic acids, preferably C7-C 13 aliphatic repeat units XY resulting from the polycondensation of aminocarboxylic acids or having an average number of carbon atoms per indicated nitrogen atom ranging from 6 to 18, preferably from 7 to 13, - At least one C6-C 18 diamine X, wherein the diamine is selected from linear or branched aliphatic diamines or mixtures thereof, and - At least one C6-C 18 Aliphatic dicarboxylic acid Y, XY is an aliphatic repeating unit obtained by polycondensation of Z is at least one optional polyamide repeat unit, Z can be present in an amount of up to 30% by weight relative to the total weight W / Z, preferably up to 15% by weight relative to the total weight W / Z. b. 0-4% by weight, preferably 0-2% of at least one plasticizer; c. 0% to 20% by weight of at least one impact modifier; d. 0-37 wt. % of at least one additive; wherein the sum of a.+b.+c.+d. is equal to 100% of the total weight of the composition; at least one layer (1) made of a composition, excluding fuel transport structure extending from said tank to said vehicle motor.

[0024] Thus, layer (I) in this embodiment consists solely of said composition, which itself consists solely of components a, b, c, and d, the sum of components a, b, c, and d being equal to 100% by weight.

[0025] Advantageously, 90% to 98% of the total length of the tube is located inside the tank.

[0026] Advantageously, 95% to 98% of the total length of the tube is located inside the tank.

[0027] More specifically, more than 98% of the total length of the tube is located within the tank.

[0028] The term "partially annular" means that the tube has a corrugated tubular shape over part of its length. The annular portion can form a single portion or multiple portions of the structure, where two annular portions are separated by a smooth portion.

[0029] The annular portion(s) allow for increased deformation and elongation of the tubular structure, especially in areas of the tank where small angles are required.

[0030] Advantageously, the tubular structure is circular over at least 10% of its length.

[0031] Advantageously, the tubular structure is circular over 10 to more than 90% of its length.

[0032] Advantageously, the tubular structure is circular over 20-90% of its length.

[0033] Advantageously, the tubular structure is circular over 30-90% of its length.

[0034] Advantageously, the tubular structure is circular over 40-90% of its length.

[0035] Advantageously, the tubular structure is circular over 50-90% of its length.

[0036] Advantageously, the tubular structure is circular over more than 60-90% of its length.

[0037] Advantageously, the tubular structure is circular over more than 70-90% of its length.

[0038] Advantageously, the tubular structure is circular over more than 80-90% of its length.

[0039] Advantageously, the tubular structure is circular over more than 90% of its length.

[0040] The expression "capable of being at least partially submerged in the tank" means that the structure is either not submerged or has at least 30% of its length submerged in fuel, regardless of the fill level of the tank.

[0041] It is quite clear that this ratio depends on the fuel fill level in the tank and the value thus given corresponds to a tank containing the maximum amount of fuel that the tank can contain.

[0042] Advantageously, at least 40% of the length of said structure is submerged in the fuel.

[0043] Advantageously, at least 50% of the length of said structure is submerged in the fuel.

[0044] Advantageously, at least 60% of the length of said structure is submerged in the fuel.

[0045] Advantageously, at least 70% of the length of said structure is submerged in the fuel.

[0046] Advantageously, at least 80% of the length of said structure is submerged in the fuel.

[0047] In another embodiment, the structure is at least partially within the tank but is not submerged regardless of the fill level of the tank.

[0048] The tubular structure of the present invention is intended to transport fuel to a tank and therefore does not relate to a tubular structure for transporting fuel from a tank to a motor or within a vehicle motor, even though it is quite clear that the structure of the present invention has a small portion that is located outside the tank.

[0049] Nevertheless, this part is fixed to a coupling device that makes it possible to connect the tubular structure of the invention to a tubular structure for transporting fuel from the tank to the motor, and therefore cannot be considered as this latter structure for transporting fuel from the tank to the motor.

[0050] It is quite clear that in the presence of plasticizers and / or impact modifiers and / or additives, a person skilled in the art will vary the proportion of aliphatic polyamide so that the sum a.+b.+c.+d is equal to 100%. DETAILED DESCRIPTION OF THE INVENTION

[0051] <Regarding Layer (1)>

[0052] The layer (1) comprises 39 to 100% by weight, in particular 41 to 100% by weight, of at least one aliphatic polyamide of the formula W / Z.

[0053] According to the present application, the term "polyamide" is also written as PA, - homopolymers (or homopolyamides), copolymers or copolyamides based on different amide units, - polyamide alloys, when polyamide is the main component; Includes.

[0054] There is also a category of copolyamides in a broad sense, which is not preferred but forms part of the scope of the present invention. These are copolyamides that contain not only amide units (which will be the majority and thus are considered copolyamides in a broad sense), but also non-amide units, such as ether units. The best-known examples are PEBA, i.e., polyether-block-amides, and their copolyamide-ester-ether, copolyamide-ether or copolyamide-ester variants. Among these, PEBA-12 with polyamide units identical to those of PA12 and PEBA-612 with polyamide units identical to those of PA612 can be mentioned.

[0055] The nomenclature used to define polyamides is described in ISO standard 1874-1:1992 "Plastiques - Materiaux polyamides (PA) pour moulage and extrusion - Partie 1: Designation", particularly on page 3 (Tables 1 and 2), and is well-known to those skilled in the art.

[0056] In one embodiment, the tubular structure of the present invention consists of at least one layer (1).

[0057] The tubular structure can include a plurality of identical or different, particularly identical, layers (1).

[0058] In another embodiment, the tubular structure of the present invention consists of a single layer (1), but may also include other layers.

[0059] In yet another embodiment, the structure is a single layer and consists of a single layer (1).

[0060] When the tubular structure is a single-layer structure, the structure is thus in contact with gasoline by both its outer surface and its inner surface.

[0061] <Regarding the <W / Z> repeating unit> <X

[0062] <W:An aliphatic repeating unit obtained from the polycondensation of at least one amino carboxylic acid or at least one lactam>

[0063] In a first variant of the present invention, the repeating aliphatic unit W is at least one C6-C 18 amino carboxylic acid, preferably C7-C 13 obtained from the polycondensation of amino carboxylic acids.

[0064] Advantageously, the amino carboxylic acid contains 9 to 12 carbon atoms. As a result, the amino carboxylic acid can be selected from 9-aminononanoic acid (denoted as 9), 10-aminodecanoic acid (denoted as 10), 11-aminoundecanoic acid (denoted as 11) and 12-aminododecanoic acid (denoted as 12), and advantageously the amino carboxylic acid is 11-aminoundecanoic acid.

[0065] In a second variant of the present invention, the repeating aliphatic unit W is at least one C6-C 18 lactam, preferably C7-C 13 obtained from the polycondensation of lactams.

[0066] Advantageously, the lactam contains 9 to 12 carbon atoms. As a result, the lactam can be selected from decanolactam (denoted as 10), undecanolactam (denoted as 11) and laurolactam or lauryllactam (denoted as 12), and advantageously the lactam is lauryllactam.

[0067] However, for the production of this same unit W, it is surely possible to anticipate the use of mixtures of two or more amino carboxylic acids, mixtures of two or more lactams, as well as mixtures of one, two or more amino carboxylic acids and one, two or more lactams.

[0068] In a particularly preferred method, the repeating unit W is obtained from a single amino carboxylic acid or from a single lactam.

[0069] In one embodiment, the amino carboxylic acid or C as a raw material12 Repeating units containing at least 20% of repeating units obtained from polycondensation of units derived from lactams are excluded from the definition of W.

[0070] In another embodiment, the aminocarboxylic acid or C as a raw material 12 Repeating units containing at least 20% of repeating units obtained from polycondensation of units derived from lactams are excluded from the flexible tubular structure of the present invention regardless of the number of layers of the structure.

[0071] In another embodiment, C 12 Repeating units obtained from polycondensation of lactams or aminocarboxylic acids are excluded from the definition of W.

[0072] In yet another embodiment, the C as a raw material 12 Repeating units obtained from polycondensation of lactams or aminocarboxylic acids are excluded from the flexible tubular structure of the present invention regardless of the number of layers of the structure.

[0073] <W: aliphatic repeating unit X.Y>

[0074] The aliphatic repeating unit X.Y is at least one linear or branched C6-C 18 , preferably C7-C 13 aliphatic diamine X or mixtures thereof, and at least one C6-C 18 , preferably C7-C 13 units obtained from polycondensation of aliphatic dicarboxylic acid Y.

[0075] The molar ratio of diamine to dicarboxylic acid is preferably stoichiometric.

[0076] The aliphatic diamine used to obtain this repeating unit X.Y is an aliphatic diamine having a linear main chain containing 6-18 carbon atoms.

[0077] This linear backbone can optionally contain one or more methyl and / or ethyl substituents, and in the latter configuration it is called a "branched aliphatic diamine." If the backbone does not contain any substituents, the aliphatic diamine is called a "linear aliphatic diamine."

[0078] The aliphatic diamine used to obtain this repeat unit XY, whether or not it contains methyl and / or ethyl substituents on the backbone, contains 6 to 18 carbon atoms, especially 7 to 13 carbon atoms.

[0079] When this diamine is a linear aliphatic diamine, it is in particular of the formula H2N-(CH2) x It corresponds to -NH2 and can be selected, for example, from hexanediamine, heptanediamine, octanediamine, nonanediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, hexadecanediamine and octadecenediamine. All of the linear aliphatic diamines just cited can be biologically sourced within the meaning of standard ASTM D6866.

[0080] When this diamine is a branched aliphatic diamine, it can in particular be 2-methyl-pentanediamine, 2-methyl-1,8-octanediamine or trimethylene (2,2,4 or 2,4,4) hexanediamine.

[0081] The dicarboxylic acids contain 6 to 18 carbon atoms, especially 7 to 13 carbon atoms.

[0082] The aliphatic dicarboxylic acid may be selected from linear or branched aliphatic dicarboxylic acids.

[0083] When the dicarboxylic acid is aliphatic and linear, it can be selected from adipic acid (6), pimelic acid (7), suberic acid (8), azelaic acid (9), sebacic acid (10), undecanedioic acid (11), dodecanedioic acid (12), brassilic acid (13), tetradecanedioic acid (14), hexadecanedioic acid (16), octadecanedioic acid (18), octadecenedioic acid (18).

[0084] Advantageously, the layer (1) comprises a composition comprising at least 49% by weight of said at least one aliphatic polyamide.

[0085] Advantageously, the layer (1) comprises a composition comprising at least 50% by weight of said at least one aliphatic polyamide.

[0086] Advantageously, the layer (1) comprises a composition comprising at least 60% by weight of said at least one aliphatic polyamide.

[0087] Advantageously, the layer (1) comprises a composition comprising at least 70% by weight of said at least one aliphatic polyamide.

[0088] Advantageously, the layer (1) comprises a composition comprising at least 80% by weight of said at least one aliphatic polyamide.

[0089] <Z: Any repeating unit>

[0090] Z can be any polyamide repeating unit, whether aliphatic, cycloaliphatic, semi-aromatic or aromatic.

[0091] Z can be present up to 30% by weight based on the total weight W / Z.

[0092] Advantageously, Z is present up to 25% by weight.

[0093] Advantageously, Z is present up to 20% by weight.

[0094] Advantageously, Z is present in an amount of up to 15% by weight.

[0095] Advantageously, Z is present in an amount of up to 10% by weight.

[0096] Advantageously, Z is present in an amount of up to 5% by weight.

[0097] Advantageously, Z is equal to 0% by weight.

[0098] <About plasticizers>

[0099] The plasticizer is chosen in particular from benzenesulfonamide derivatives, such as n-butylbenzenesulfonamide (BBSA), ethyltoluenesulfonamide or N-cyclohexyltoluenesulfonamide, esters of hydroxybenzoic acid, such as ethyl-2-hexylparahydroxybenzoate and decyl-2-hexylparahydroxybenzoate, esters or ethers of tetrahydrofurfuryl alcohol, such as oligoethyleneoxytetrahydrofurfuryl alcohol, and esters of citric acid or hydroxymalonic acid, such as oligoethyleneoxymalonate.

[0100] It would not be outside the scope of the present invention to use a mixture of plasticizers.

[0101] A particularly preferred plasticizer is n-butylbenzenesulfonamide (BBSA).

[0102] The plasticizer can be introduced into the polyamide during or after polycondensation.

[0103] The plasticizer used in the composition is present in a weight proportion of 0 to 4%, in particular 0 to 2%.

[0104] Above 4%, the proportion of plasticizer and therefore the proportion of extractables is too high.

[0105] In one embodiment, above 2%, the proportion of plasticizer is too high and therefore the proportion of extractables is too high.

[0106] In yet another embodiment, the plasticizer used in the composition is in a weight ratio of 0.1 to 2%.

[0107] Since the tube is partly circular, this geometry of the tube structure provides a certain flexibility, so that the composition of the layer (1) does not necessarily require the presence of a plasticizer.

[0108] In an advantageous embodiment, said composition of said layer (1) does not contain a plasticizer.

[0109] Advantageously, the tubular structure is circular for 10 to more than 90% of its length, and said composition of layer (1) does not contain a plasticizer.

[0110] <About impact modifiers>

[0111] The tubular structure of the invention is placed inside the tank, so that the latter is protected from impacts and does not require special protection against impacts, so that impact modifiers can be omitted.

[0112] Nevertheless, the presence of an impact modifier may be useful and / or desirable to provide flexibility.

[0113] The expression "impact modifier" means a polyolefin-based polymer, in particular a polyolefin, having a flexural modulus of less than 100 MPa, measured according to standard ISO 178:2010 (23°C RH50), and a Tg (measured according to standard 11357-2:2013 at the level of the inflection point of the DSC thermogram) of less than 0°C.

[0114] The impact modifier may be a PEBA (polyether-block-amide) block polymer having a flexural modulus of less than 200 MPa.

[0115] The polyolefin of the impact modifier may be functionalized, unfunctionalized, or may be a mixture of at least one functionalized polyolefin and / or at least one unfunctionalized polyolefin.

[0116] In particular, the polyolefins are partly or entirely related to functional groups selected from carboxylic acid functional groups, carboxylic anhydrides and epoxides, in particular ethylene and propylene copolymers (EPR) with elastomeric properties, ethylene-propylene-diene copolymers (EPDM) with elastomeric properties and ethylene / alkyl(meth)acrylate copolymers, higher ethylene-alkene copolymers, in particular ethylene-octene copolymers, ethylene-alkylacrylate-maleic anhydride terpolymers.

[0117] Advantageously, the impact modifier is chosen from Fusabond® N493, Fusabond MF416D, Lotader®, in particular Lotader® 4700, Lotader® 5500, Lotader® 7500 or Lotader® 3410, Exellor® VA1801 or VA1803, Amplify® GR216, Tafmer® MH5020, MH5040, MH7020, MH7010, or mixtures thereof, when they are in a mixture of two, in a ratio ranging from 0.1 / 99.9 to 99.9 / 0.1, preferably from 1 / 2 to 2 / 1.

[0118] By way of example, the impact modifier is selected from the following mixtures: Fusabond® N493 / Lotader®, in particular Fusabond® N493 / Lotader® 5500 or Fusabond® N493 / Lotader® 7500.

[0119] The impact modifier may be PEBA (polyether-block-amide).

[0120] The proportion of impact modifier in the composition of the layer (1) is present in the range of 0 to 20%.

[0121] In one embodiment, the impact modifier is present at 3-20%.

[0122] In another embodiment, the impact modifier is present in an amount of 10 to 18% by weight, based on the total weight of the components of the composition of layer (1).

[0123] In yet another embodiment, the impact modifier is present in a weight ratio of 0% relative to the total weight of the components of the composition of layer (1) and is therefore excluded from said composition of layer (1).

[0124] <About additives>

[0125] The additive(s) d. are selected from carbon black, graphite, graphene, carbon fibers, carbon nanotubes, in particular carbon black and carbon nanotubes, antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, fire retardants, nucleating agents, pigments, reinforcing fibers, waxes and mixtures thereof.

[0126] In this application, plasticizers and impact modifiers are excluded from the definition of additives.

[0127] The composition of the layer (1) may contain 0 to 35% by weight of at least one additive relative to the total weight of the composition.

[0128] Thus, said layer (1) can be conductive or non-conductive depending on the presence of carbon black, graphite, graphene, carbon fibres or carbon nanotubes.

[0129] Advantageously, one of these additives is an antioxidant.

[0130] The antioxidant can be an organic antioxidant, more commonly a combination of organic antioxidants such as phenolic type primary antioxidants (e.g., Ciba's Irganox® 245 or 1098 or 1010 types), secondary phosphite antioxidants, phenolic or phosphorus-based antioxidants. Amine-based antioxidants such as Chemtura's Naugard® 445 or multifunctional stabilizers such as Clariant's Nylostab® S-EED can also be used.

[0131] The antioxidant may also be a mineral antioxidant, such as a copper-based antioxidant. Examples of such mineral antioxidants include copper halides and copper acetate, particularly CuI / KI. Secondly, other metals, such as silver, can optionally be considered, but are known to be less effective. These copper-containing compounds are typically associated with alkali metal halides, particularly potassium.

[0132] The light stabilizer can be a HALS, which stands for hindered amine light stabilizer (e.g., Ciba's Tinuvin® 770).

[0133] An example of a UV absorber is Tinuvin® 312 from Ciba.

[0134] According to a first variant, the additive is carbon black, in particular in a proportion of 5 to 32%, in particular 15 to 28%, relative to the total weight of the composition of layer (I). The additive, being carbon black, can optionally contain at least one additive other than carbon black, graphite, graphene, carbon fibers and carbon nanotubes, in a proportion of 0 to 5% by weight. The proportion of the additive, being carbon black and optionally other relative additives, corresponds to d.

[0135] According to a second variant, the additive is carbon nanotubes in a proportion of 0.5 to 10% by weight, in particular 2 to 7% by weight, in particular 4 to 5% by weight, relative to the total weight of the composition.

[0136] In these variations, partial substitution of carbon nanotubes for carbon black, or vice versa, would not depart from the scope of the present invention.

[0137] The sum of a.+b.+c.+d. by weight equals 100% of the total weight of the composition, so that no components other than a., b., c., and d. can be present in the composition.

[0138] It is quite clear that whatever the high and low values ​​of the various components a., b., c., and d., the total will be 100%. In other words, even though the addition of a high value of one of components a., b., c., and d. and a low value of another component may exceed 100%, it is quite clear that one skilled in the art would vary one or more of components a., b., c., and d. so that the total amount of components does not exceed 100% by weight.

[0139] Whether the tubular structure consists of a single layer or other layers as described above, the tubular structure is at least partially disposed inside the tank, meaning that more than 90% of the total length of the tube is disposed inside the tank, such that said tubular structure can be at least partially submerged in the tank, such that when the tubular structure is at least partially submerged, both the inner layer of said tubular structure and the outer layer of said tubular structure, at least partially the outer layer, will be in contact with the fuel, and therefore is not a structure for transporting fuel between the tank and the motor of a vehicle. Thus, in embodiments where said structure is a single layer structure, the monolayer (1) will be on both the inner surface and on the outer surface, the latter in contact with the fuel if the monolayer (1) is at least partially submerged.

[0140] Also, the tubular structure of the present invention is not the tubular structure present in a motor.

[0141] Polyamides, as defined hereinabove in general terms, whether homopolyamides, copolyamides or alloys, can be distinguished by the number of carbon atoms per nitrogen atom, it being known that there are as many nitrogen atoms as there are amide groups (-CO-NH-).

[0142] The tubular structure containing the aliphatic polyamide is made of at least one C6-C 18 Lactam or at least one C6-C 18 At least one polyamide, denoted C, obtained from the polycondensation of aminocarboxylic acids.

[0143] In one embodiment, the tubular structure as defined hereinbefore is characterized in that the at least one aliphatic polyamide is a polyamide selected from the group consisting of at least one C-C 18 Lactams, preferably C7-C 13 Lactam or at least one C6-C 18 Aminocarboxylic acids, preferably C7-C 13 They are characterized by being at least one polyamide, denoted C, obtained from the polycondensation of aminocarboxylic acids and having an average number of carbon atoms per nitrogen atom, denoted CC, ranging from 9 to 18, advantageously from 10 to 18.

[0144] Throughout the specification, the expression "in the range of... to..." is inclusive and has the same meaning as the expression "to...".

[0145] Polyamides represented by C obtained from the polycondensation of at least one C7 or C8 lactam or at least one C7 or C8 aminocarboxylic acid, C In order to obtain an average number of carbon atoms per nitrogen atom represented by the formula (I) in the range of 9 to 18, the polyamide represented by the formula (I) is such that the second unit is C C It is quite clear that the polyamide or polyamide blend must have an average number of carbon atoms per nitrogen atom greater than 9, as expressed by the formula:

[0146] Advantageously, said at least one aliphatic polyamide is at least one C-C 18 Lactams, preferably C7-C 13 Lactam or at least one C6-C 18 Aminocarboxylic acids, preferably C7-C 13 C obtained from the polycondensation of aminocarboxylic acids in the range of 9 to 18, advantageously 10 to 18 C It is a single polyamide, denoted as C, having an average number of carbon atoms per nitrogen atom denoted as

[0147] In another embodiment, component a. of the composition further comprises: - C in the range of 4 to 8.5, advantageously 4 to 7 A at least one polyamide, denoted A, having an average number of carbon atoms per nitrogen atom represented by - a melting temperature of more than 180 ° C and a C in the range of 7 to 10, advantageously 7.5 to 9.5 B at least one polyamide, denoted B, having an average number of carbon atoms per nitrogen atom represented by or a mixture thereof, and another polyamide selected from the weighted average enthalpy of fusion of the polyamide is greater than 25 J / g (DSC); The average number of carbon atoms per nitrogen atom of polyamides A, B and C satisfies the following strict inequality C A <C B <C C Further satisfy.

[0148] The polyamides designated A and B, having a melting temperature of 180°C or higher, are any polyamides resulting from the polycondensation of at least one lactam or at least one aminocarboxylic acid, each having an average number of carbon atoms per nitrogen atom, designated CA, ranging from 4 to 8.5, preferably from 4 to 7, and an average number of carbon atoms per nitrogen atom, designated CB, ranging from 7 to 10, preferably from 7.5 to 9.5, but may also be polyamides PAX'Y' resulting from the polycondensation of a linear or branched aliphatic diamine X', provided that the average number of carbon atoms per nitrogen atom is respected for each of the polyamides A and B.

[0149] Advantageously, the difference in the average number of carbon atoms per nitrogen atom (C B -C A ) and / or (C C -C B ) is in the range of 1 to 4, preferably in the range of 2 to 3.

[0150] The enthalpy of fusion and melting temperature of polyamides are determined according to ISO 11357-3:2013.

[0151] Therefore, the composition of the layer (1) can contain a polyamide represented by C and a polyamide represented by A, or a polyamide represented by C and a polyamide represented by B, or a polyamide represented by C, a polyamide represented by A and a polyamide represented by B.

[0152] The proportion by weight of the various polyamides in the composition is variable, meaning that one of the polyamides designated A, B or C is in the majority relative to the total C+A, C+B or C+A+B.

[0153] In a first variant, said component a. of said composition has a C A The composition further comprises at least one polyamide, designated A, having an average number of carbon atoms per nitrogen atom designated A=(a) / (b).

[0154] Advantageously, the melting temperature of polyamide A is greater than or equal to 210°C.

[0155] In a second variant, said component a. of said composition has a melting temperature of greater than or equal to 180°C and a C value ranging from 7 to 10, advantageously from 7.5 to 9.5. B and an average number of carbon atoms per nitrogen atom represented by B.

[0156] Advantageously, the melting temperature of polyamide B is below 200°C.

[0157] In a third variant, said component a. of said composition further comprises a C A at least one polyamide, denoted A, having an average number of carbon atoms per nitrogen atom, denoted C; a melting temperature of 180° C. or higher and a C value ranging from 7 to 10, advantageously from 7.5 to 9.5; B and an average number of carbon atoms per nitrogen atom represented by B.

[0158] Advantageously, polyamide A has a melting temperature of 210°C or higher and / or polyamide B has a melting temperature of 200°C or lower.

[0159] Advantageously, said composition of the three variants defined above comprises between 34 and 84% by weight, preferably between 50 and 80% by weight, of aliphatic polyamide C relative to the total weight of polyamides present in said composition.

[0160] More advantageously, said composition of the three variants defined above comprises between 60 and 80% by weight of aliphatic polyamide C relative to the total weight of polyamides present in said composition.

[0161] More advantageously, said composition of the three variants defined above comprises between 70 and 80% by weight of aliphatic polyamide C relative to the total weight of polyamides present in said composition.

[0162] The aliphatic polyamide having a tubular structure is at least one C6-C 18 Lactams, preferably C7-C 13 Lactam or at least one C6-C 18 Aminocarboxylic acids, preferably C7-C 13 When it is a polyamide designated C resulting from the polycondensation of aminocarboxylic acids, said polyamide C is advantageously chosen from PA11 and PA12, advantageously PA11.

[0163] In a first variant, said polyamide C is advantageously chosen from PA11 and PA12, advantageously PA11, and polyamide A is chosen from PA6, PA46 and PA66.

[0164] In a second variant, said polyamide C is advantageously chosen from PA11 and PA12, advantageously PA11, and polyamide B is chosen from PA610 and PA612.

[0165] In a third variant, said polyamide C is advantageously chosen from PA11 and PA12, advantageously PA11, polyamide B is chosen from PA610 and PA612 and polyamide A is chosen from PA6, PA46 and PA66.

[0166] Advantageously, each of the polyamides A, B and C has a melting enthalpy higher than 25 J / g (DSC).

[0167] In one embodiment, the tubular structure is characterized in that W in the aliphatic polyamide of formula W / Z is at least one aliphatic repeating unit XY, which is a polyamide represented by B' having a melting temperature of 180°C or higher and an average number of carbon atoms per nitrogen atom, represented by CB', ranging from 7 to 10, advantageously from 7.5 to 9.5, or a polyamide represented by C' having an average number of carbon atoms per nitrogen atom, represented by CC', ranging from 9 to 18, advantageously from 10 to 18.

[0168] In another embodiment, the tubular structure defined above is characterized in that W in said at least one aliphatic polyamide of formula W / Z is at least one aliphatic repeating unit XY, which is a polyamide represented by B' having a melting temperature equal to or greater than 180°C and an average number of carbon atoms per nitrogen atom, represented by CB', ranging from 7 to 10, advantageously from 7.5 to 9.5, or a polyamide represented by C' having an average number of carbon atoms per nitrogen atom, represented by CC', ranging from 9 to 18, advantageously from 10 to 18.

[0169] Therefore, repeating units derived from the polycondensation of lactam and / or aminocarboxylic acid are excluded from the polyamide represented by B' or C'.

[0170] Advantageously, said aliphatic polyamide is a single polyamide designated B' or a single polyamide designated C'.

[0171] In one embodiment, the component a. of the composition consisting of at least one aliphatic polyamide represented by B' or represented by C' further comprises: - C in the range of 4 to 8.5, advantageously 4 to 7 A at least one polyamide represented by A having an average number of carbon atoms per nitrogen atom represented by When said aliphatic polyamide is C', it has a melting temperature of greater than or equal to 180°C and a C ranging from 7 to 10, advantageously from 7.5 to 9.5. B at least one polyamide, represented by B″, having an average number of carbon atoms per nitrogen atom represented by - if the aliphatic polyamide is B', C in the range of 9 to 18, advantageously 10 to 18; c” at least one polyamide, represented by C″, having an average number of carbon atoms per nitrogen atom represented by or mixtures thereof, and another polyamide selected from the weighted average enthalpy of fusion of the polyamide is greater than 25 J / g (DSC); The average number of carbon atoms per nitrogen atom in units A, B', B'', C' and C'' satisfies the following strict inequality C A <C B’ or C B” <C C’ or C C” Further satisfy.

[0172] The polyamide designated A is a polyamide obtained as described above, the polyamide designated B" is a polyamide obtained as described above for polyamide B, and the polyamide designated C" is a polyamide obtained as described above for polyamide C, provided that the average number of carbon atoms per nitrogen atom is respected for each of the polyamides A, B" and C", respectively.

[0173] Advantageously, the difference in the average number of carbon atoms per nitrogen atom (CB'-CA) and / or (CC'-CB) and / or (C C” -C B” ) is 1 to 4, preferably 2 to 3.

[0174] Thus, the composition of said layer (1) may comprise: - a polyamide represented by B' and a polyamide represented by A, - a polyamide represented by B' and a polyamide represented by C"; - a polyamide represented by B', a polyamide represented by A and a polyamide represented by C"; - a polyamide represented by C' and a polyamide represented by A, - a polyamide represented by C' and a polyamide represented by B"; - a polyamide represented by C', a polyamide represented by A and a polyamide represented by B''.

[0175] The proportion by weight of the various polyamides in the composition is variable, meaning that one of the polyamides designated A, B' or C" represents the majority relative to the total of polyamides A+B'+C" or one of the polyamides designated A, B" or C' represents the majority relative to the total of polyamides A+B"+C' present in the composition.

[0176] In a first variant, the at least one aliphatic polyamide represented by B' has a C A The composition further comprises at least one polyamide represented by A having an average number of carbon atoms per nitrogen atom represented by

[0177] In a second variant, the at least one aliphatic polyamide represented by B' has a C C” The composition further comprises at least one polyamide, represented by C″, having an average number of carbon atoms per nitrogen atom represented by

[0178] In a third variant, the at least one aliphatic polyamide represented by B' has a C A and at least one polyamide, represented by A, having an average number of carbon atoms per nitrogen atom represented by C” The composition further comprises at least one polyamide, represented by C″, having an average number of carbon atoms per nitrogen atom represented by

[0179] In a fourth variant, the at least one aliphatic polyamide represented by C' has a C A The composition further comprises at least one polyamide represented by A having an average number of carbon atoms per nitrogen atom represented by

[0180] In a fifth variant, the at least one aliphatic polyamide, represented by C', has a melting temperature greater than or equal to 180°C and a C B’and an average number of carbon atoms per nitrogen atom represented by B″.

[0181] In a sixth variant, the at least one aliphatic polyamide represented by C' has a C A and at least one polyamide represented by A having a melting temperature of 180° C. or more and an average number of carbon atoms per nitrogen atom represented by C in the range of 7 to 10, advantageously 7.5 to 9.5. B” and an average number of carbon atoms per nitrogen atom represented by B″.

[0182] Advantageously, the melting temperature of polyamide A is greater than or equal to 210°C and / or the melting temperature of polyamide C" is less than or equal to 200°C and / or the melting temperature of polyamide B" is greater than or equal to 180°C.

[0183] Advantageously, said composition of three of the six variants defined above comprises between 34 and 84% by weight, preferably between 50 and 80% by weight, of aliphatic polyamide B' relative to the total weight of polyamides present in said composition.

[0184] More advantageously, the composition of three of the six variants defined above comprises between 60 and 80% by weight of aliphatic polyamide B' relative to the total weight of polyamides present in the composition.

[0185] More advantageously, the composition of three of the six variants defined above comprises between 70 and 80% by weight of aliphatic polyamide B' relative to the total weight of polyamides present in the composition.

[0186] Advantageously, said composition of three of the six variants defined above comprises between 34 and 84% by weight, preferably between 50 and 80% by weight, of aliphatic polyamide C' relative to the total weight of polyamides present in said composition.

[0187] More advantageously, the composition of three of the six variants defined above comprises between 60 and 80% by weight of aliphatic polyamide C' relative to the total weight of polyamides present in the composition.

[0188] More advantageously, said composition of three of the six variants defined above comprises 70 to 80% by weight of aliphatic polyamide C' relative to the total weight of polyamides present in said composition.

[0189] When said at least one aliphatic polyamide of the tubular structure is an aliphatic repeating unit of a polyamide represented by B', said polyamide B' is advantageously selected from PA610 and PA612, advantageously PA610.

[0190] When said at least one aliphatic polyamide of the tubular structure is an aliphatic repeating unit of a polyamide represented by C', said polyamide C' is advantageously chosen from PA1012, PA618 and PA1010.

[0191] In a first variant, said polyamide B' is advantageously chosen from PA610 and PA612, advantageously PA610, and polyamide A is chosen from PA6, PA46 and PA66.

[0192] In a second variant, said polyamide B' is advantageously chosen from PA610 and PA612, advantageously PA610, and polyamide C'' is chosen from PA11, PA12, PA1012, PA618 and PA1010.

[0193] In a third variant, said polyamide B' is advantageously chosen from PA610 and PA612, advantageously PA610, polyamide A is chosen from PA6, PA46 and PA66, and polyamide C" is chosen from PA11, PA12, PA1012, PA618 and PA1010.

[0194] In a fourth variant, said polyamide C' is advantageously chosen from PA1012, PA618 and PA1010, and polyamide A is chosen from PA6, PA46 and PA66.

[0195] In a fifth variant, said polyamide C' is advantageously chosen from PA1012, PA618 and PA1010, and polyamide B' is advantageously chosen from PA610 and PA612, advantageously PA610.

[0196] In a sixth variant, the polyamide C' is advantageously chosen from PA1012, PA618 and PA1010, the polyamide A is chosen from PA6, PA46 and PA66, and the polyamide B' is advantageously chosen from PA610 and PA612, advantageously PA610.

[0197] Advantageously, each of the polyamides A, B', B'', C' and C'' has a melting enthalpy higher than 25 J / g (DSC).

[0198] Advantageously, when the structure consists of a single layer, layer (1), the composition of said layer (1) does not contain any additives selected from carbon black, graphite, graphene, carbon fibres and carbon nanotubes.

[0199] Thus, in this embodiment, the tubular structure is non-conductive and does not include any other layers.

[0200] All the features of the various components a., b., c. and d. defined above are valid for this particular embodiment, except for the additive selected from carbon black, graphite, graphene, carbon fibers and carbon nanotubes.

[0201] Advantageously, when the tubular structure is a single layer structure, said layer (1) has a thickness of at least 600 μm.

[0202] Advantageously, said single layer tubular structure free from additives selected from carbon black, graphite, graphene, carbon fibres and carbon nanotubes is also free from plasticisers.

[0203] <Tubular structure containing at least carbon black as an additive>

[0204] In one embodiment, said tubular structure as defined above comprises at least an additive in layer (1) which is carbon black.

[0205] Other additives may be present in said layer (1), but they are non-conductive.

[0206] The tubular structure can be single or multi-layered.

[0207] Advantageously, the tubular structure is multi-layered.

[0208] In a first variant, the tubular structure defined above is characterized in that the composition of the layer (1) is a. 39 to 95 wt. %, in particular 41 to 85 wt. %, of at least one aliphatic polyamide; b. 0-4% by weight, preferably 0-2% plasticizer; c. 0-20 wt. % of at least one impact modifier; d. 5 to 32 wt. %, particularly 15 to 28 wt. % of an additive that is carbon black; and 0 to 5 wt. % of at least one additive other than carbon black, graphite, graphene, carbon fiber, and carbon nanotubes; Including, The sum a.+b.+c.+d. is equal to 100%.

[0209] The additives, plasticizers, and impact modifiers are as defined above.

[0210] In one embodiment, the tubular structure defined above is characterized in that the composition of the layer (1) is a. 39 to 95 wt. %, in particular 41 to 85 wt. %, of at least one aliphatic polyamide; b. 0-4% by weight, preferably 0-2% plasticizer; c. 0-20 wt. % of at least one impact modifier; d. 5 to 32 wt. %, particularly 15 to 28 wt. % of an additive that is carbon black; and 0 to 5 wt. % of at least one additive other than carbon black, graphite, graphene, carbon fiber, and carbon nanotubes; It consists of characterized in that the sum a.+b.+c.+d. is equal to 100% of the total weight of the composition.

[0211] In a second variant, the tubular structure defined above is characterized in that the composition of the layer (1) is a. 39 to 85 wt. %, in particular 41 to 75 wt. %, of at least one aliphatic polyamide; b. 0-4% by weight, preferably 0-2% plasticizer; c. 10 to 18 wt. % of at least one impact modifier; d. 5 to 32 wt. %, particularly 15 to 28 wt. % of an additive that is carbon black; and 0 to 5 wt. % of at least one additive other than carbon black, graphite, graphene, carbon fiber, and carbon nanotubes; Including, The sum a.+b.+c.+d. is equal to 100%.

[0212] In one embodiment, the tubular structure defined above is characterized in that the composition of the layer (1) is a. 39 to 85 wt. %, in particular 41 to 75 wt. %, of at least one aliphatic polyamide; b. 0-4% by weight, preferably 0-2% plasticizer; c. 10 to 18 wt. % of at least one impact modifier; d. 5 to 32 wt. %, particularly 15 to 28 wt. % of an additive that is carbon black; and 0 to 5 wt. % of at least one additive other than carbon black, graphite, graphene, carbon fiber, and carbon nanotubes; It consists of characterized in that the sum a.+b.+c.+d. is equal to 100% of the total weight of the composition.

[0213] <Tubular structure in which the additive is at least carbon nanotubes>

[0214] In one embodiment, said tubular structure as defined above comprises at least an additive in layer (1) which is a carbon nanotube.

[0215] Other additives may be present in said layer (1), but they are non-conductive.

[0216] The tubular structure can be single or multi-layered.

[0217] In a first variant, the tubular structure defined above is characterized in that the composition of the layer (1) is a. 70 to 99.5% by weight, in particular 80 to 98% by weight, in particular 80% and 96% by weight, of at least one aliphatic polyamide; b. 0-4% by weight, preferably 0-2% plasticizer; c. 0-20% of at least one impact modifier; d. 0.5 to 10 wt. %, preferably 2 to 7 wt. %, especially 4 to 5 wt. % of an additive which is carbon nanotubes; and 0 to 19% by weight, preferably 0 to 22% by weight, in particular 0 to 24% by weight of at least one additive other than carbon black, graphite, graphene, carbon fibers and carbon nanotubes, Including, The sum a.+b.+c.+d. is equal to 100%.

[0218] In one embodiment, the tubular structure defined above is characterized in that the composition of the layer (1) is a. 70 to 99.5% by weight, in particular 80 to 98% by weight, in particular 80% and 96% by weight, of at least one aliphatic polyamide; b. 0-4% by weight, preferably 0-2% plasticizer; c. 0-20% of at least one impact modifier; d. 0.5 to 10 wt. %, preferably 2 to 7 wt. %, especially 4 to 5 wt. % of an additive which is carbon nanotubes; and 0 to 19% by weight, preferably 0 to 22% by weight, in particular 0 to 24% by weight of at least one additive other than carbon black, graphite, graphene, carbon fibers and carbon nanotubes, It consists of characterized in that the sum a.+b.+c.+d. is equal to 100% of the total weight of the composition.

[0219] In a second variant, the tubular structure defined above is characterized in that the composition of the layer (1) is a. 70 to 89.5% by weight, in particular 80 to 88% by weight, in particular 80% by weight and 86% by weight, of at least one aliphatic polyamide; b. 0-4% by weight, preferably 0-2% plasticizer; c. 10-18% of at least one impact modifier; d. 0.5 to 10 wt. %, preferably 2 to 7 wt. %, especially 4 to 5 wt. % of an additive which is carbon nanotubes; and 0 to 19% by weight, preferably 0 to 22% by weight, in particular 0 to 24% by weight of at least one additive other than carbon black, graphite, graphene, carbon fibers and carbon nanotubes, Including, The sum a.+b.+c.+d. is equal to 100%.

[0220] In one embodiment, the tubular structure defined above is characterized in that the composition of the layer (1) is a. 70 to 89.5% by weight, in particular 80 to 88% by weight, in particular 80% by weight and 86% by weight, of at least one aliphatic polyamide; b. 0-4% by weight, preferably 0-2% plasticizer; c. 10-18% of at least one impact modifier; d. 0.5 to 10 wt. %, preferably 2 to 7 wt. %, especially 4 to 5 wt. % of an additive which is carbon nanotubes; and 0 to 19% by weight, preferably 0 to 22% by weight, in particular 0 to 24% by weight of at least one additive other than carbon black, graphite, graphene, carbon fibers and carbon nanotubes, It consists of characterized in that the sum a.+b.+c.+d. is equal to 100% of the total weight of the composition.

[0221] Advantageously, one layer (1) of said tubular structure defined above is free of plasticizers.

[0222] <Tubular structure comprising at least one layer (1) and at least one layer (2)>

[0223] In another embodiment, the tubular structure defined above is characterized in that it comprises at least one second layer (2), which may be conductive or non-conductive, in particular conductive, said layer (1) being arranged above or below said layer (2).

[0224] The term "on" means the outside of the tubular structure, so that said layer (1) is the outer layer and said layer (2) is the inner layer.

[0225] The term "under" means inside the tubular structure, so that said layer (1) is the inner layer and said layer (2) is the outer layer.

[0226] Thus, the tubular structure corresponds to a multilayer structure (MLT).

[0227] Advantageously, said layer (1) is placed on top of said layer (2).

[0228] Advantageously, the thickness of layer (1) in the MLT structure is between about 600 μm and about 950 μm.

[0229] Advantageously, the thickness of said layer (2) in the MLT structure represents less than 25% of the total thickness of the MLT.

[0230] Advantageously, when said second layer (2) is conductive, its thickness is between 50 and 200 μm.

[0231] Advantageously, said tubular structure comprising at least one second layer (2) is characterized in that said second layer (2) comprises at least one fluorinated material such as an aliphatic polyamide or PVDF, or a functionalized fluorinated material such as a functionalized ethylene-tetrafluoroethylene (ETFE) copolymer, a functionalized ethylene-tetrafluoroethylene-hexafluoropropylene (EFEP) copolymer, a tetrafluoroethylene-perfluoro(alkyl vinyl ether)-chlorotrifluoroethylene (CPT) copolymer.

[0232] All technical features detailed above for layer (1) of the tubular structure are valid for this embodiment in which there is at least one layer (1) and at least one layer (2).

[0233] The at least one second layer (2) is conductive or non-conductive, which means that the at least one second layer may comprise an additive selected from carbon black, graphite, graphene, carbon fibers and carbon nanotubes, and the layer (1) is conductive or non-conductive.

[0234] In a first variant, said at least one second layer (2) does not contain a plasticizer.

[0235] In a second variant, the at least one second layer (2) is conductive and comprises from 0.5 to 10%, preferably from 2 to 7%, in particular from 4 to 5% by weight of additives which are carbon nanotubes, or from 5 to 24% by weight, in particular from 15 to 24% by weight of additives which are carbon black, relative to the total weight of the composition of said layer (2).

[0236] In a third variant, the at least one second layer (2) is conductive and comprises from 0.5 to 10% by weight, preferably from 2 to 7% by weight, in particular from 4 to 5% by weight, of additives which are carbon nanotubes, or from 5 to 24% by weight, in particular from 15 to 24% by weight, of additives which are carbon black, relative to the total weight of the composition of said layer (2), and is free of plasticizers.

[0237] In a fourth variant, the at least one second layer (2) is conductive and comprises 0.5 to 10% by weight, preferably 2 to 7% by weight, in particular 4 to 5% by weight, of additives which are carbon nanotubes, or 5 to 24% by weight, in particular 15 to 24% by weight, of additives which are carbon black, relative to the total weight of the composition of the layer (2), and the layer (1) is non-conductive.

[0238] In a fifth variant, the at least one second layer (2) is conductive and comprises 0.5 to 10% by weight, preferably 2 to 7% by weight, in particular 4 to 5% by weight, of additives which are carbon nanotubes, or 5 to 24% by weight, in particular 15 to 24% by weight, of additives which are carbon black, relative to the total weight of the composition of layer (2), and layer (2) does not comprise a plasticizer, and layer (1) is non-conductive.

[0239] In a sixth variant, the at least one second layer (2) is conductive and comprises 0.5 to 10% by weight, preferably 2 to 7% by weight, in particular 4 to 5% by weight, of an additive which is carbon nanotubes, or 5 to 24% by weight, in particular 15 to 24% by weight, of an additive which is carbon black, relative to the total weight of the composition of the layer (2), the layer (2) being free of plasticizers, and the layer (1) being non-conductive and free of plasticizers.

[0240] In another embodiment, the tubular structure defined above is characterized in that it comprises two conductive or non-conductive layers (2), in particular a conductive layer, said layer (1) being arranged between said two layers (2).

[0241] The expression "barrier layer" means a layer that has low permeability to fuel, in particular alcoholic gasoline, so that it does not allow substantial passage of fuel, in particular alcoholic gasoline, into the atmosphere.

[0242] In particular, the expression "barrier layer" means that the proportion of fuel, particularly alcohol-based gasoline, released into the atmosphere is less than 20 g.mm / m, as measured with CE10 fuel at 60°C. 2 . means less than days.

[0243] The fuel permeability, in particular the gasoline permeability, is measured at 60°C on plates made of polymeric material by gravimetric method using CE10, i.e. isooctane / toluene / ethanol = 45 / 45 / 10% by volume, and CE85, i.e. isooctane / toluene / ethanol = 7.5 / 7.5 / 85% by volume. The instantaneous permeability is zero during an induction period and then gradually increases to an equilibrium value which corresponds to the permeability value in the permanent steady state. This value obtained in the permanent steady state is considered to be the permeability of the material.

[0244] This barrier property is essential for tubing in contact with the atmosphere.

[0245] In the case of the tubular structure of the present invention, the latter is submerged in the fuel and no barrier layer is required.

[0246] In one variant, the tubular structure as defined above, comprising at least one second layer (2), does not have a barrier layer, so that the tubular structure consists only of aliphatic polyamide.

[0247] The aliphatic polyamide of layer (2) is as defined above and may contain the same additives, impact modifiers, plasticizers as the polyamide of layer (1), in the same ratio ranges as those of layer (1).

[0248] The fluorinated material may contain additives similar to those of the polyamide of layer (1), in the same proportion ranges as those of layer (1). Advantageously, the second layer (2) comprises a composition comprising at least one aliphatic polyamide, as defined for layer (1).

[0249] In another embodiment, the tubular structure comprising at least one second layer (2) as defined above also comprises a third layer (2') which may be identical to or different from the second layer (2).

[0250] Advantageously, said layer (2') comprises a composition comprising a polyamide as defined for said layer (2).

[0251] Advantageously, said layers (2) and (2') are conductive and layer (1) is non-conductive.

[0252] Advantageously, when the tubular structure comprises at least one layer (1) and at least one layer (2), the thickness of said layer (1) is between 60% and 95% of the total thickness of the tube.

[0253] According to another aspect, the invention relates to the use of a tubular structure as defined above for transporting fuel to a tank, in particular for transporting gasoline to a tank.

[0254] All the characteristics previously defined for the tubular structure are valid for this use.

[0255] According to another aspect, the invention relates to the use of a tubular structure as defined above for satisfying an extractables test, said test consisting in particular of filling said multilayer tubular structure MLT with FAM-B alcohol-based gasoline, heating the assembly at 60°C for 96 hours, emptying the assembly by filtering it and transferring it to a beaker, then evaporating the filtrate from the beaker at ambient temperature and finally weighing this residue, the proportion of which is about 10 / m on the tube inner surface. 2 g or less, preferably 6 g / m 2 Must be less than or equal to:

[0256] According to another aspect, the present invention relates to a method for measuring the extract of tubular structures as defined above, comprising the following steps: 1) filling a tubular structure with FAM-B alcohol-based gasoline; 2) heating the gasoline-immersed tubular structure at 60°C for 96 hours; 3) emptying by simultaneous filtration into a beaker; 4) evaporating the filtrate from the beaker at ambient temperature; 5) Weighing the residue after evaporation, and the proportion of the residue is about 6 g / m on the inner tube surface. 2 The steps that must be: [Example]

[0257] The present invention will now be described in more detail using the following non-limiting examples.

[0258] The following structures were prepared by extrusion:

[0259] The multilayer tubes are produced by coextrusion using an industrial McNeil multilayer extrusion line equipped with five extruders connected to a multilayer extrusion head using a spiral mandrel.

[0260] The screws used are extrusion monoscrews with screw profiles adapted for polyamides. In addition to the five extruders and the multi-layer extrusion head, the extrusion line is equipped with: A die punch assembly located at the end of the coextrusion head, the inner diameter of the die and the outer diameter of the punch being selected depending on the structure to be produced and the material from which it is constructed, as well as the size of the tube and the line speed; A vacuum tank with adjustable vacuum level, in which water is circulated at a temperature of approximately 20°C. This allows the gauges to be immersed and the tubes to be formed to their final dimensions. The gauge diameter is adapted to the dimensions of the tube to be produced, typically 8.5-10 mm for a tube with an outer diameter of 8 mm and a thickness of 1 mm. A series of cooling baths that maintain the water at around 20°C and make it possible to cool the tubes along their path from the head to the drawing table; diameter measuring instruments, · Pull-out table.

[0261] A five-extruder configuration is used to produce tubing ranging from two to five layers, so for configurations with fewer than five layers, several extruders are fed with the same material.

[0262] For structures containing six layers, an additional extruder is connected and a spiral mandrel is added to the existing head to bring the inner layer into contact with the fluid.

[0263] Before testing, to ensure the best properties and good extrusion quality for the tubing, make sure the extruded material has a pre-extrusion residual moisture content of less than 0.08%, otherwise an additional step of drying the material before testing (typically in a vacuum oven) is performed overnight at 80°C.

[0264] Tubes meeting the properties disclosed in this patent application were removed after the extrusion parameters had stabilized and the dimensions of the tubes in question no longer changed over time. The diameter was controlled by a laser diameter gauge installed at the end of the line.

[0265] Generally, the line speed is typically 20 m / min. The line speed is generally 5 to 100 m / min.

[0266] The extruder screw speed depends on the layer thickness and the screw diameter, as known to those skilled in the art.

[0267] Generally, the temperature of the extruder and tooling (head and coupling devices) must be adjusted to be sufficiently higher than the melting temperature of the compositions in question, so that the compositions remain in a molten state and do not solidify and clog the machinery.

[0268] The tubular structures were tested under different parameters (Table I).

[0269] All layer thicknesses are expressed in μm.

[0270] The amount of extractables, burst pressure properties and flexibility properties were determined.

[0271] [Table 1] TIFF2025131603000002.tif222154(1) Burst pressure is the burst pressure (according to DIN53758) after at least 96 hours of FAM-B biogas has been inside, so a high value that can withstand the pressure is required. The more "+" signs there are, the better the burst pressure. (2) Flexibility and flexural modulus (according to ISO178) of the tube when adjusted at 23°C under RH50. The lower the modulus, the higher the flexibility, which is convenient for fitting the tube. The more "+" marks there are, the better the flexibility. (3) Extractables. This test consisted in filling a tube with FAM-B alcohol-based gasoline at 60°C for 96 hours, then emptying it, filtering it into a beaker, then evaporating it, and weighing the residue, the latter being the (inner surface of the tube) m 2 Preferably, the amount is 6 g or less per 1000 ml of alcohol-based gasoline. FAM B alcohol-based gasoline is disclosed in the standards DIN 51604-1:1982, DIN 51604-2:1984 and DIN 51604-3:1984. In summary, first, FAM A alcohol-based gasoline is prepared with a mixture of 50% toluene, 30% isooctane, 15% diisobutylene and 5% ethanol, and then FAM B is prepared.

[0272] <Composition>

[0273] PA12-TL denotes a composition based on polyamide 12 containing 6% plasticizer, 6% EPR1, and 1.2% organic stabilizer. The melting temperature of this composition is 175°C.

[0274] PA11-TL denotes a composition based on polyamide 11 containing 5% plasticizer, 6% impact modifier of ethylene / ethyl acrylate / anhydride type in a mass ratio of 68.5 / 30 / 1.5 (MFI 6 at 190 °C under 2.16 kg), and 1.2% organic stabilizer. The melting temperature of this composition is 185 °C. PA12-NoPlast = PA12-TL without plasticizer (the latter is replaced by PA12) PA11-NoPlast = PA11-TL without plasticizer (the latter is replaced by PA11) PA610-TL = PA610 + 12% EPR1 impact modifier + organic stabilizer + 10% plasticizer PA610-NoPlast = PA610-TL without plasticizer (the latter is replaced by PA610) PA612-TL = PA612 + 12% EPR1 impact modifier + organic stabilizer + 9% plasticizer PA612-NoPlast = PA612-TL without plasticizer (the latter is replaced by PA612) PA612-NoPlast-B = PA612-TL without plasticizer or EPR1 (these are replaced with PA612) PA11cond-noplast = Mn15000 PA11 + 9% EPR1 + 26% Ensaco type carbon black 250g PA6-NoPlast = PA6 + 12% EPR1 impact modifier + organic stabilizer Binder - NoPlast = composition based on 48.8% PA612 (defined elsewhere), 30% PA6 (defined elsewhere), and 20% EPR1 type impact modifier, and 1.2% organic stabilizer. EFEPc = Functionalized EFEP and Daikin Neoflon RP5000AS type conductor PA11-P = Polyamide 11-based composition containing 1% plasticizer, 6% impact modifier of ethylene / ethyl acrylate / anhydride in a mass ratio of 68.5 / 30 / 1.5 (MFI 6 at 190°C under 2.16 kg), and 1.2% organic stabilizer. The melting temperature of this composition is 188°C.

[0275] <Components of the composition>

[0276] PA12: Polyamide 12 with a Mn (number average molecular weight) of 35,000. Its melting temperature is 178°C and its melting enthalpy is 54 kJ / m 2 is. PA11: Polyamide 11 with a Mn (number average molecular weight) of 29,000. Its melting temperature is 190°C and its melting enthalpy is 56 kJ / m 2 is. PA610: Polyamide 6.10 with a number average molecular weight (Mn) of 30,000. Its melting temperature is 223°C and its enthalpy of fusion is 61 kJ / m 2 is. PA612: Polyamide 6.12 with a number average molecular weight (Mn) of 29,000. Its melting temperature is 218°C and its enthalpy of fusion is 67 kJ / m 2 is. PA6: Polyamide 6 with a number average molecular weight (Mn) of 28,000. Its melting temperature is 220°C and its melting enthalpy is 68 kJ / m 2 is. EPR1: EPR of 10 kg of Exxon's Exxellor® VA1801 with MFI of 9 (230°C or less) functionalized with a reactive group having an anhydride functional group (0.5-1% by mass). Organic stabilizer = 1.2% organic stabilizer consisting of 0.8% phenol (Lowinox® 44B25 from Great Lakes), 0.2% phosphite (Irgafos® 168 from Ciba), 0.2% UV stabilizer (Tinuvin® 312 from Ciba). Plasticizer = BBSA (benzyl butyl sulfonamide)

Claims

1. A partly annular flexible tubular structure to be placed at least partly inside a fuel tank, in particular a gasoline or diesel tank, in particular a gasoline tank, of a vehicle, said structure being at least partly submersible in said tank and intended to transport said fuel to said tank, said tubular structure comprising: a. 39% to 100% by weight, in particular 41% to 100% by weight, of at least one aliphatic polyamide of the formula W / Z, provided that: W is at least one C ６ ~C １８ Lactams, preferably C ７ ~C １３ lactam, or at least one C ６ ~C １８ Aminocarboxylic acids, preferably C ７ ~C １３ aliphatic repeat units XY resulting from the polycondensation of aminocarboxylic acids or having an average number of carbon atoms per indicated nitrogen atom ranging from 6 to 18, preferably from 7 to 13, - at least one C ６ ~C １８ diamine X, wherein the diamine is selected from linear or branched aliphatic diamines or mixtures thereof; and - at least one C ６ ~C １８ Aliphatic dicarboxylic acid Y, XY is an aliphatic repeating unit obtained by polycondensation of Z is at least one optional polyamide repeat unit, Z can be present in an amount of up to 30% by weight relative to the total weight W / Z, preferably up to 15% by weight relative to the total weight W / Z. b. 0-4% by weight, preferably 0-2% of at least one plasticizer; c. 0% to 20% of at least one impact modifier; d. 0 to 37 wt. % of at least one additive; Including, The sum of a. + b. + c. + d. is equal to 100%; It comprises at least one layer (1) comprising a composition, Tubular structure, excluding fuel transport structure extending from said tank to said vehicle motor.

2. The at least one aliphatic polyamide is at least one C ６ ~C １８ Lactams, preferably C ７ ~C １３ lactam, or at least one C ６ ~C １８ Aminocarboxylic acids, preferably C ７ ~C １３ C esters obtained from the polycondensation of aminocarboxylic acids, in the range of 9 to 18, preferably 10 to 18 Ｃ 2. The tubular structure of claim 1, characterized in that it is at least one polyamide designated C, having an average number of carbon atoms per nitrogen atom designated C.

3. Component a. of said composition further comprises: C in the range from 4 to 8.5, preferably from 4 to 7 Ａ at least one polyamide represented by A having an average number of carbon atoms per nitrogen atom represented by a melting temperature of 180°C or more and a C in the range of 7 to 10, preferably 7.5 to 9.5 Ｂ and at least one polyamide represented by B having an average number of carbon atoms per nitrogen atom represented by or a mixture thereof, and another polyamide selected from the weighted average enthalpy of fusion of the polyamide is greater than 25 J / g (DSC); The average number of carbon atoms per nitrogen atom of polyamides A, B and C satisfies the following strict inequality C Ａ <C Ｂ <C Ｃ Further satisfying 3. The tubular structure according to claim 2, characterized in that:

4. 4. A tubular structure according to claim 2 or 3, characterized in that the composition comprises from 34 to 84% by weight, preferably from 50 to 80% by weight, of aliphatic polyamide C relative to the total weight of polyamides present in the composition.

5. 5. A tubular structure according to claim 3 or 4, characterized in that polyamide A is selected from PA6, PA46 and PA66, polyamide B is selected from PA610, PA612, preferably PA610, and polyamide C is selected from PA11 and PA12.

6. In said at least one aliphatic polyamide of formula W / Z, W has a melting temperature of 180° C. or higher and a C in the range of 7 to 10, preferably 7.5 to 9.

5. Ｂ’ and an average number of carbon atoms per nitrogen atom represented by B' in the range of 9 to 18, preferably 10 to 18. Ｃ’ 2. The tubular structure of claim 1, characterized in that at least one aliphatic repeat unit XY is a polyamide represented by C' having an average number of carbon atoms per nitrogen atom represented by

7. The component a. of the composition comprising at least one aliphatic polyamide represented by B' or represented by C' further comprises: C in the range from 4 to 8.5, preferably from 4 to 7 Ａ at least one polyamide represented by A having an average number of carbon atoms per nitrogen atom represented by If the aliphatic polyamide is C', it has a melting temperature of at least 180°C and a C ranging from 7 to 10, advantageously from 7.5 to 9.

5. Ｂ and at least one polyamide, represented by B″, having an average number of carbon atoms per nitrogen atom represented by C in the range from 9 to 18, preferably from 10 to 18, if the aliphatic polyamide is B' ｃ” at least one polyamide, represented by C″, having an average number of carbon atoms per nitrogen atom represented by or mixtures thereof, and another polyamide selected from the weighted average enthalpy of fusion of the polyamide is greater than 25 J / g (DSC); The average number of carbon atoms per nitrogen atom in units A, B', B'', C' and C'' satisfies the following strict inequality C Ａ <C Ｂ’ or C Ｂ” <C Ｃ’ or C Ｃ” Further satisfying 7. A tubular structure according to claim 6, characterized in that it comprises:

8. 8. A tubular structure according to claim 6 or 7, characterized in that the composition comprises from 34 to 84% by weight, preferably from 50 to 80% by weight, of aliphatic polyamide B' or aliphatic polyamide C' relative to the total weight of polyamides present in the composition.

9. 9. A tubular structure according to claim 7 or 8, characterized in that polyamide A is selected from PA6, PA46 and PA66, polyamide B' is selected from PA610, PA612, preferably PA610, and polyamide C" is selected from PA11, PA12, PA1012, PA618 and PA1010, or polyamide A is selected from PA6, PA46 and PA66, polyamide B" is selected from PA610, PA612, preferably PA610, and polyamide C' is selected from PA1012, PA618 and PA1010.

10. 10. A tubular structure according to any one of claims 1 to 9, characterized in that the additive d. is selected from carbon black, graphite, graphene, carbon fibers, carbon nanotubes, in particular carbon black and carbon nanotubes, antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, fire retardants, nucleating agents, pigments, reinforcing fibers, waxes, and mixtures thereof.

11. 11. The tubular structure of claim 10, wherein the additive is at least carbon black.

12. The composition of the layer (1) a. 39% to 95% by weight, in particular 41% to 85% by weight, of at least one aliphatic polyamide; b. 0% to 4% by weight, preferably 0-2%, of a plasticizer; c. 0% to 20% of at least one impact modifier; d. 5% to 32% by weight, particularly 15 to 28% by weight, of an additive that is carbon black; and 0-5 wt. % of at least one additive other than carbon black, graphite, graphene, carbon fiber, and carbon nanotubes; Including, 11. The tubular structure according to claim 10, characterized in that the sum a. + b. + c. + d. is equal to 100%.

13. The composition of the layer (1) a. 39% to 85% by weight, in particular 41% to 75% by weight, of at least one aliphatic polyamide; b. 0% to 4% by weight, preferably 0-2%, of a plasticizer; c. 10% to 18% of at least one impact modifier; d. 5% to 32% by weight, particularly 15 to 28% by weight, of an additive that is carbon black; and 0-5 wt. % of at least one additive other than carbon black, graphite, graphene, carbon fiber, and carbon nanotubes; Including, 13. A tubular structure according to claim 11 or 12, characterized in that the sum a. + b. + c. + d. is equal to 100%.

14. 11. The tubular structure of claim 10, wherein the additive is at least carbon nanotubes.

15. The composition of the layer (1) a. 70% to 99.5% by weight, particularly 80% to 98% by weight, and particularly 80% and 96% by weight, of at least one aliphatic polyamide; b. 0% to 4% by weight, preferably 0-2%, of a plasticizer; c. 0% to 20% of at least one impact modifier; d. 0.5% to 10% by weight, preferably 2-7% by weight, especially 4-5% by weight of an additive which is carbon nanotubes; and 0 to 19% by weight, preferably 0 to 22% by weight, in particular 0 to 24% by weight of at least one additive other than carbon black, graphite, graphene, carbon fibers and carbon nanotubes, Including, 15. The tubular structure according to claim 14, characterized in that the sum a. + b. + c. + d. is equal to 100%.

16. The composition of the layer (1) a. 70% to 89.5% by weight, particularly 80% to 88% by weight, and particularly 80% and 86% by weight, of at least one aliphatic polyamide; b. 0% to 4% by weight, preferably 0-2%, of a plasticizer; c. 10% to 18% of at least one impact modifier; d. 0.5% to 10% by weight, preferably 2-7% by weight, especially 4-5% by weight of an additive which is carbon nanotubes; and 0 to 19% by weight, preferably 0 to 22% by weight, in particular 0 to 24% by weight of at least one additive other than carbon black, graphite, graphene, carbon fibers and carbon nanotubes, Including, 16. A tubular structure according to claim 14 or 15, characterized in that the sum a. + b. + c. + d. is equal to 100%.

17. A tubular structure according to any one of the preceding claims, characterized in that said layer (1) is free of plasticizers.

18. A tubular structure according to any one of claims 1 to 17, characterized in that the structure is circular over at least 10% of its length.

19. A tubular structure according to any one of claims 1 to 18, characterized in that at least 90% of the length of the structure is inside the tank.

20. A tubular structure according to any one of claims 1 to 19, characterized in that at least 30%, preferably at least 80%, of the length of the structure is submerged in fuel.

21. 21. A tubular structure according to any one of claims 1 to 12 and 17 to 20, characterized in that it consists of a single layer and does not contain any additive selected from carbon black, graphite, graphene, carbon fibres and carbon nanotubes.

22. 22. A tubular structure according to claim 21, characterized in that the thickness of said layer (1) is at least 600 μm.

23. 23. A tubular structure according to any one of claims 1 to 20 and 22, characterized in that it comprises at least one second layer (2), which is conductive or non-conductive, in particular conductive, said layer (1) being arranged above or below said layer (2).

24. 24. A tubular structure according to claim 23, characterized in that said layer (1) is arranged on top of said layer (2).

25. 25. A tubular structure according to claim 23 or 24, characterized in that the second layer (2) comprises at least one aliphatic polyamide or a fluorinated material such as PVDF or a functionalized fluorinated material such as a functionalized ethylene-tetrafluoroethylene (ETFE) copolymer, a functionalized ethylene-tetrafluoroethylene-hexafluoropropylene (EFEP) copolymer, a tetrafluoroethylene-perfluoro(alkyl vinyl ether)-chlorotrifluoroethylene (CPT) copolymer.

26. 25. Tubular structure according to claim 23 or 24, characterized in that the structure does not comprise a barrier layer and the second layer (2) comprises at least one aliphatic polyamide.

27. Use of a tubular structure according to any one of claims 1 to 26 for transporting fuel to a tank, in particular for transporting gasoline to a tank.

28. Use of a tubular structure according to any one of claims 1 to 26 for satisfying an extractables test, said test in particular consisting in filling said multilayer tubular structure MLT with FAM-B alcohol-based gasoline, heating the assembly at 60°C for 96 hours, then emptying the FAM-B alcohol-based gasoline by filtering it into a beaker, then evaporating the filtrate from said beaker at ambient temperature and finally weighing this residue, the proportion of said residue being about 10 g / m2 on the tube inner surface. ２ Preferably 6 g / m or less ２ Must be used below.

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