MULTILAYER STRUCTURE BASED ON RECYCLED POLYAMIDE

Abstract

The present invention relates to a multilayer tubular structure (MLT) for transporting automotive fluids, comprising at least three layers: at least one layer (1) made of a composition comprising predominantly at least one semi-crystalline aliphatic polyamide, said composition being made of at least 50% recycled material from a multilayer tube that has been used for transporting automotive fluids, said tube being made of a composition that comprises predominantly at least one polyamide, at least one layer (2) made of a composition comprising predominantly at least one semi-crystalline aliphatic polyamide and optionally at least one impact modifier, and when layer (2) is made of a composition comprising predominantly at least one semi-crystalline aliphatic polyamide that is PA12 and / or PA612 and / or PA1010, then said composition comprises said impact modifier,and at least one layer (2') made of a composition comprising predominantly at least one semi-crystalline aliphatic polyamide, said layer (2) and said layer (2') each being made of at least 90% non-recycled material.

Description

Title of the invention: MULTILAYER STRUCTURE BASED ON RECYCLED POLYAMIDE

[0001] Every year, several million motor vehicles become unusable worldwide. An end-of-life vehicle (ELV) contains many toxic and polluting products (liquid or solid): used oil, battery, air conditioning fluid, explosive airbag components, etc. If treated in poor conditions, this waste can lead to soil and water pollution, as well as accidents. ELVs are therefore considered hazardous waste.

[0002] A large quantity of vehicle components can be recovered and recycled, in the form of used spare parts or raw materials. Parts intended for reuse (headlights, indicators, engine, radiator, starter, hood, wings, doors, etc.) are dismantled and stored for resale.

[0003] Non-recyclable carcasses and parts (ferrous and non-ferrous metals, plastics, glass, rubber, etc.) are crushed for recovery or landfill.

[0004] European Directive 2000 / 53 / EC on end-of-life vehicles has set a reuse and recovery rate of 95% by weight per vehicle from 2015.

[0005] There should therefore only remain 5% of ultimate waste, that is to say waste which is not capable of being treated under the technical and economic conditions of the moment and which will be incinerated or evacuated to specific storage centers.

[0006] The 95% reused and recovered are the subject of:

[0007] Energy recovery: use of waste (oils, tires, plastics, etc.) as a means of energy production, by direct incineration with or without other waste;

[0008] Material recovery: Reuse or re-employment: new use of a part which retains the same use and is not transformed, or Recycling: operation aimed at introducing materials from waste into the production cycle, in total or partial replacement of a virgin material.

[0009] A motor vehicle contains a large number of pipes, in particular pipes intended for the transport of fluids such as air, oil (for example for cooling the automatic gearbox "TOC, Transmission Oil Cooler), water, a urea solution, a glycol-based coolant, a fuel such as gasoline, in particular bio-gasoline or diesel, in particular bio-diesel, or hydrogen.

[0010] These pipes can be single-layer and / or multi-layer tubular structures, in particular based on polyamide(s).

[0011] When the motor vehicle is out of use, the various pipes present in it are generally very or too degraded to be able to be reused as, in the form of a tube, without risk or without this leading to excessively degraded usage properties.

[0012] Indeed, the tubes, particularly under the engine hood, are placed in a severe thermo-oxidative environment due to the heat released by the engine which can typically reach 150°C and the presence of air and therefore oxygen. Each increase in temperature of 10°C typically results in a halving of the service life of the tubes as well as the degradation of certain additives of said tubes such as stabilizers.

[0013] Furthermore, a fuel transport pipe, for example a polyamide pipe which contains a plasticizer, has lost most of its plasticizer when it reaches the end of its life and the polyamide constituting it initially present is depolymerized and / or degraded and has lost most of its stabilizers, which prevents its safe reuse.

[0014] Until now, the used automobile pipe is not reused and is often incinerated, but this then contributes to global warming, the reduction of which is becoming one of the major challenges of the 21st century.

[0015] Furthermore, several car manufacturers have the more or less long-term objective of recycling 100% of the vehicles they produce in order to achieve an environmental impact equal to zero.

[0016] Consequently, the supply of recycled pipes to these manufacturers becomes essential and then makes it possible to reduce the quantity of pipes to be thrown away or incinerated.

[0017] The present invention therefore relates to a multi-layer tubular structure (MLT) intended for the transport of automotive fluids, in particular air, oil (for example for cooling the automatic gearbox "TOC, Transmission Oil Cooler), water, a urea solution, a glycol-based coolant, or a fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel, or hydrogen, comprising at least three layers:

[0018] at least one layer (1) consisting of a composition comprising at least 50% of polyamide resins consisting of at least one first polyamide resin comprising mainly aliphatic units and at least one second resin comprising mainly aromatic units,

[0019] said composition being made up of at least 50% recycled material originating from a multilayer tube having initially transported automotive fluids, in particular as defined above, said tube being made up of a composition which predominantly comprises at least one polyamide,

[0020] at least one layer (2) consisting of a composition comprising predominantly at least one semi-crystalline aliphatic polyamide and optionally at least one impact modifier, and when the layer (2) consists of a composition comprising predominantly at least one semi-crystalline aliphatic polyamide which is PA12 and / or PA612 and / or PA1010, then said composition comprises said impact modifier, and

[0021] at least one layer (2') consisting of a composition comprising predominantly at least one semi-crystalline aliphatic polyamide,

[0022] said layer (2) and said layer (2') being made of at least 90% non-recycled material.

[0023] The inventors have therefore surprisingly found that a layer based on polyamide resins consisting of at least one first polyamide resin comprising mainly aliphatic units and at least one second resin comprising mainly aromatic units,

[0024] and made of at least 50% recycled material, in particular embedded between two polyamide-based layers and made of non-recycled material, allowed the constitution of a multilayer tubular structure comprising at least three layers capable of transporting an automotive fluid, in particular air, oil, water, a urea solution, a glycol-based coolant, or a fuel such as gasoline, in particular bio-gasoline or diesel, in particular bio-diesel, or hydrogen, regardless of the type of fluid initially transported by the recycled multilayer tube constituting the embedded layer.

[0025] The term "fluid" means a gas or liquid used in the automobile, in particular air, oil, water, a urea solution, a glycol-based coolant, or a fuel such as gasoline, in particular alcohol-based gasoline, bio-gasoline or diesel, in particular bio-diesel, or hydrogen.

[0026] Advantageously, said fluid designates fuels, in particular gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular biodiesel.

[0027] The term "gasoline" designates a mixture of hydrocarbons resulting from the distillation of petroleum to which additives or alcohols such as methanol and ethanol may be added, the alcohols being able to be the majority components in certain cases.

[0028] The term "alcohol-based gasoline" refers to gasoline to which methanol or ethanol has been added. It also refers to E95-type gasoline that does not contain petroleum distillation products.

[0029] The expression "polyamide-based" means at least 50% by weight of polyamide in the layer.

[0030] The expression "a composition comprising predominantly at least one polyamide..." means at least 50% by weight of said polyamide in the composition.

[0031] In one embodiment, said layer (2) consists of a composition comprising predominantly at least one semi-crystalline aliphatic polyamide and at least one impact modifier in a proportion of 3 to 45% by weight relative to the total weight of the composition. Regarding layer (1)

[0032] The layer (1) is made up of a composition comprising at least 50% of polyamide resins made up of at least one first polyamide resin comprising mainly aliphatic units and at least one second resin comprising mainly aromatic units,

[0033] said composition being made up of at least 50% recycled material originating from a multilayer tube intended for the transport of automobile fluids.

[0034] The nomenclature used to define polyamides is described in ISO 1874-1:2011 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation" and is well known to those skilled in the art.

[0035] The term “polyamide” according to the invention designates both a homopolyamide and a copolyamide.

[0036] The expression “a first polyamide resin comprising predominantly aliphatic units” means that said first resin comprises at least 50% aliphatic units.

[0037] The expression “a second polyamide resin comprising predominantly aromatic units” means that said first resin comprises at least 50% aromatic units.

[0038] In one embodiment, said first polyamide resin comprising predominantly aliphatic units is a semi-crystalline polyamide.

[0039] Advantageously, said first polyamide resin comprising predominantly aliphatic units is a semi-crystalline aliphatic polyamide.

[0040] In another embodiment, said second resin comprising mainly aromatic units is a semi-crystalline polyamide.

[0041] Advantageously, said first polyamide resin comprising mainly aromatic units is a semi-crystalline semi-aromatic polyamide.

[0042] In yet another embodiment, said first polyamide resin comprising predominantly aliphatic units and said second resin comprising predominantly aromatic units are semi-crystalline polyamides.

[0043] Advantageously, said first polyamide resin comprising predominantly aliphatic units is a semi-crystalline aliphatic polyamide and said first polyamide resin comprising mainly aromatic units is a semi-crystalline semi-aromatic polyamide.

[0044] The expression "semi-crystalline polyamide" within the meaning of the invention throughout the description designates polyamides which have a melting temperature (Tf) and an enthalpy of fusion AH > 25 J / g, in particular > 40 J / g, in particular > 45 J / g, as well as a glass transition temperature (Tg) as determined by DSC according to the standard ISO 11357-1:2016 and ISO 11357-2 and 3:2013, at a heating rate of 20K / min.

[0045] Said at least one aliphatic semi-crystalline polyamide is obtained from the polycondensation of at least one lactam, or from the polycondensation of at least one amino acid, or from the polycondensation of at least one diamine Xa with at least one dicarboxylic acid Yb.

[0046] When said at least one aliphatic semi-crystalline polyamide is obtained from the polycondensation of at least one lactam, said at least one lactam may be chosen from a C6 to C18 lactam, preferably a C10 to C18 lactam, more preferably a C10 to C12 lactam. A C6 to C12 lactam is in particular caprolactam, decanolactam, undecanolactam, and lauryllactam.

[0047] When said at least one aliphatic semi-crystalline polyamide is obtained from the polycondensation of at least one lactam, it can therefore comprise a single lactam or several lactams.

[0048] Advantageously, said at least one aliphatic semi-crystalline polyamide is obtained from the polycondensation of a single lactam and said lactam is chosen from lauryllactam and undecanolactam, advantageously lauryllactam.

[0049] When said at least one aliphatic semi-crystalline polyamide is obtained from the polycondensation of at least one amino acid, said at least one amino acid may be chosen from a C6 to C18 amino acid, preferably a C10 to C18 amino acid, more preferably a C10 to C12 amino acid.

[0050] A C6 to C12 amino acid is in particular 6-aminohexanoic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 10-aminoundecanoic acid, 12-aminododecanoic acid and 11-aminoundecanoic acid as well as its derivatives, in particular N-heptyl-11-aminoundecanoic acid.

[0051] When said at least one aliphatic semi-crystalline polyamide is obtained from the polycondensation of at least one amino acid, it can therefore comprise a single amino acid or several amino acids.

[0052] Advantageously, said aliphatic semi-crystalline polyamide is obtained from the polycondensation of a single amino acid and said amino acid is chosen from 11-aminoundecanoic acid and 12-aminododecanoic acid, advantageously 11-aminoundecanoic acid.

[0053] When said at least one aliphatic semi-crystalline polyamide is obtained from the polycondensation of at least one C4-C36, preferably C5-C18, preferably C5-C12, more preferably C10-C12, diamine Xa with at least one C4-C36, preferably C6-C18, preferably C6-C12, more preferably C10-C12, diacid Yb, then said at least one Xa diamine is an aliphatic diamine and said at least one Yb diacid is an aliphatic diacid.

[0054] The diamine may be linear or branched. Advantageously, it is linear.

[0055] Said at least one C4-C36 diamine Xa may in particular be chosen from 1,4-butanediamine, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylediamine, 1,8-octamethylediamine, 1,9-nonamethylediamine, 1,10-decamethylediamine, 1,11-undecamethylediamine, 1,12-dodecamethylediamine, 1,13-tridecamethylediamine, 1,14-tetradecamethylediamine, 1,16-hexadecamethylediamine and 1,18-octadecamethylediamine, octadecenediamine, eicosanediamine, docosanediamine and the diamines obtained from from fatty acids.

[0056] Advantageously, said at least one diamine Xa is C5-C18 and chosen from 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethyldiamine, 1,8-octamethyldiamine, 1,9-nonamethyldiamine, 1,10-decamethyldiamine, 1,11-undecamethyldiamine, 1,12-dodecamethyldiamine, 1,13-tridecamethyldiamine, 1,14-tetradecamethyldiamine, 1,16-hexadecamethyldiamine and 1,18-octadecamethyldiamine.

[0057] Advantageously, said at least one diamine Xa in C5 to C12, is in particular chosen from 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylediamine, 1,8-octamethylediamine, 1,9-nonamethylediamine, 1,10-decamethylediamine, 1,11-undecamethylediamine, 1,12-dodecamethylediamine.

[0058] Advantageously, said at least one diamine Xa in C6 to C12, is in particular chosen from 1,6-hexamethylenediamine, 1,7-heptamethyldiamine, 1,8-octamethyldiamine, 1,9-nonamethyldiamine, 1,10-decamethyldiamine, 1,11-undecamethyldiamine, 1,12-dodecamethyldiamine.

[0059] Advantageously, the diamine Xa used is C10 to C12, in particular chosen from 1,10-decamethyldiamine, 1,11-undecamethyldiamine, 1,12-dodecamethyldiamine.

[0060] Said at least one C4 to C36 dicarboxylic acid Yb may be chosen from succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, and diacids obtained from fatty acids.

[0061] The diacid may be linear or branched. Advantageously, it is linear.

[0062] Advantageously, said at least one dicarboxylic acid Yb is C6 to C18 and is chosen from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid.

[0063] Advantageously, said at least one dicarboxylic acid Yb is C6 to C12 and is chosen from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid.

[0064] Advantageously, said at least one dicarboxylic acid Yb is C10 to C12 and is chosen from sebacic acid, undecanedioic acid, dodecanedioic acid.

[0065] When said aliphatic semi-crystalline polyamide is obtained from the polycondensation of at least one diamine Xa with at least one dicarboxylic acid Yb, it can therefore comprise a single diamine or several diamines and a single dicarboxylic acid or several dicarboxylic acids.

[0066] Advantageously, said aliphatic semi-crystalline polyamide is obtained from the polycondensation of a single diamine Xa with a single dicarboxylic acid Yb.

[0067] Said at least one semi-crystalline semi-aromatic polyamide is obtained from the polycondensation of at least one diamine Xa as defined above, with at least one aromatic dicarboxylic acid or a diamine Xb with a dicarboxylic acid Yb as defined above.

[0068] The aromatic dicarboxylic acid is advantageously chosen from terephthalic acid (denoted T), isophthalic acid (denoted I) and 2,6-naphthalene dicarboxylic acid (denoted N) or mixtures thereof, in particular it is chosen from terephthalic acid (denoted T), isophthalic acid (denoted I) or mixtures thereof.

[0069] The diamine Xb is advantageously an arylamine, which can be chosen from meta-xylylene diamine (MXD, CAS No.: 1477-55-0) or para-xylylene diamine (PXD, CAS No.: 539-48-0).

[0070] When said semi-crystalline semi-aromatic polyamide is obtained from the polycondensation of at least one diamine Xa with at least one aromatic dicarboxylic acid, or of at least one diamine Xb with at least one dicarboxylic acid Yb, it can therefore comprise a single diamine or several diamines and a single dicarboxylic acid or several dicarboxylic acids.

[0071] Advantageously, said aliphatic semi-crystalline polyamide is obtained from the polycondensation of a single diamine Xa with a single aromatic dicarboxylic acid or from the polycondensation of a single diamine Xb with a single dicarboxylic acid Yb.

[0072] Advantageously, said semi-crystalline semi-aromatic polyamide is obtained from the polycondensation of at least one diamine Xa with at least one acid dicarboxylic acid chosen from terephthalic acid and isophthalic acid, in particular terephthalic acid, or said semi-crystalline semi-aromatic polyamide is obtained from the polycondensation of at least one diamine Xb with at least one dicarboxylic acid Yb.

[0073] In particular, said at least one diamine Xa in C6 to C12 is chosen from 1,6-hexamethylenediamine, 1,7-heptamethyldiamine, 1,8-octamethyldiamine, 1,9-nonamethyldiamine, 1,10-decamethyldiamine, 1,11-undecamethyldiamine, 1,12-dodecamethyldiamine and said at least one dicarboxylic acid is an acid chosen from terephthalic acid and isophthalic acid, in particular terephthalic acid.

[0074] In particular, said at least one diamine Xb is an arylamine chosen from meta-xylylene diamine (MXD, CAS No.: 1477-55-0) or para-xylylene diamine (PXD, CAS No.: 539-48-0) and said at least one dicarboxylic acid Yb is C6 to C18 and is chosen from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid.

[0075] Advantageously, said at least one dicarboxylic acid Yb is C6 to C12 and is chosen from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid.

[0076] Each of these semi-aromatic polyamides can be copolymerized with a lactam or an amino acid to result in structures such as PA11 / 9T, PA11 / 10T, PA11 / 12T, PA12 / 9T, PA12 / 10T and PA12 / 12T or PA11 / MXD6, PA11 / MXD10, PA12 / MXD6, PA12 / MXD10.

[0077] Advantageously, said composition of the layer (1) comprises at least 60% by weight, in particular at least 70% by weight, in particular at least 80% by weight, more particularly at least 90% by weight of polyamide resins consisting of at least one first polyamide resin comprising predominantly aliphatic units and at least one second resin comprising predominantly aromatic units, relative to the total weight of said composition.

[0078] Said composition of the layer (1) is made up of at least 50% recycled material originating from a multilayer tube intended for the transport of automobile fluids.

[0079] This means either that the “at least one majority polyamide” of said composition corresponds in its entirety to what is called “at least 50% recycled material” or that at least 50% by weight of all the constituents of the composition are of recycled origin from multilayer tube.

[0080] The recycled material may come from a multilayer tube, said multilayer tubes having been intended for the transport of automobile fluid. Said tube is therefore a tube used, that is to say that it has been used for at least one year for the transport of the said fluid defined above.

[0081] Said multilayer tube comprises at least one layer consisting of a composition comprising a semi-crystalline aliphatic polyamide and optionally impact modifiers and / or additives, and at least one layer comprising a mixture of semi-crystalline aliphatic and semi-crystalline semi-aromatic polyamide and optionally impact modifiers and / or additives. It may therefore also comprise other layers consisting of a thermoplastic polymer other than a semi-crystalline aliphatic polyamide or a mixture of semi-crystalline aliphatic and semi-crystalline semi-aromatic polyamide, such as for example a polypropylene, a semi-aromatic polyamide or a polyethylene vinyl alcohol (EVOH).

[0082] It is also obvious that the multilayer tube can also be a mixture of different types of multilayer tube, provided that at least one of the layers of one of the types of multilayer tube is made of a semi-crystalline aliphatic polyamide.

[0083] If the mixed tubes are incompatible with each other, then the addition of a second semi-crystalline aliphatic polyamide denoted B and having an average number of carbon atoms per nitrogen atom denoted CB = Ce - 1, preferably CB = Ce - 2 and preferably a third polyamide makes it possible to make them compatible.

[0084] Said multilayer tube which was intended for the transport of automobile fluid and which is therefore used can undergo several different treatments in order to be recycled:

[0085] It can simply be crushed;

[0086] It can be ground and recompounded, that is to say that after grinding, the ground particles are fed into an extruder, in particular of the co-rotating twin-screw type, or of the co-kneader type (Buss), where they are remixed by melting. The molten material comes out of the extruder in rods which are cooled and cut into granules;

[0087] It can be ground and recompounded and reformulated, that is to say that after grinding, the ground particles are fed into an extruder, as defined above where they are remixed by melting with the addition of at least one compound chosen from a semi-crystalline aliphatic polyamide, of recycled or non-recycled origin, at least one impact modifier, a plasticizer, an additive and antistatic fillers. The molten material emerges from the extruder in rods which are cooled and cut into granules.

[0088] In one embodiment, said composition of the layer (1) comprises:

[0089] at least 50% by weight, in particular from 50% to 99% by weight, in particular from 50% to 98% by weight of at least one semi-crystalline aliphatic polyamide noted C having an average number of carbon atoms per nitrogen atom noted Cc of from 6 to 18, advantageously from 8 to 12;

[0090] from 0 to 50% by weight of at least one semi-crystalline aliphatic polyamide noted B and having an average number of carbon atoms per nitrogen atom noted CB = Ce - 1, preferably CB = Cc - 2;

[0091] from 0 to 50% by weight of a semi-crystalline aliphatic polyamide noted A having an average number of carbon atoms per nitrogen atom noted CA = CB - 1, preferably CA = CB - 2;

[0092] from 0 to 45% by weight of at least one impact modifier, in particular from 1 to 45% by weight of at least one impact modifier, in particular from 2 to 45% by weight of at least one impact modifier,

[0093] from 0 to 20% by weight of at least one plasticizer,

[0094] from 0 to 2% by weight of at least one additive,

[0095] the sum of the constituents being equal to 100%.

[0096] In another embodiment, said composition of the layer (1) consists of:

[0097] at least 50% by weight, in particular from 50% to 99% by weight, in particular from 50% to 98% by weight, of at least one semi-crystalline aliphatic polyamide noted C having an average number of carbon atoms per nitrogen atom noted Cc of from 6 to 18, advantageously from 8 to 12;

[0098] from 0 to 25% by weight of at least one semi-crystalline aliphatic polyamide noted B and having an average number of carbon atoms per nitrogen atom noted CB = Cc - 1, preferably CB = Cc - 2;

[0099] from 0 to 25% by weight of a semi-crystalline aliphatic polyamide noted A having an average number of carbon atoms per nitrogen atom noted CA = CB - 1, preferably CA = CB - 2;

[0100] from 0 to 45% by weight of at least one impact modifier, in particular from 1 to 45% by weight of at least one impact modifier, in particular from 2 to 45% by weight of at least one impact modifier,

[0101] from 0 to 20% of at least one plasticizer,

[0102] from 0 to 2% by weight of at least one additive,

[0103] the sum of the constituents being equal to 100%.

[0104] The polyamides noted A, B and C can be of recycled or non-recycled origin on the condition that the composition of the layer (1) is made up of at least 50% recycled material.

[0105] Advantageously, the Tf of the majority aliphatic semi-crystalline polyamide of the layer (1) is <225°C, in particular <200°C, as determined according to ISO 11357-3: 2013, at a heating rate of 20K / min.

[0106] In one embodiment, said composition of the layer (1) is free of plasticizer and / or impact modifier and said recycled material comes from a tube chosen from a crushed tube, a crushed and recompounded tube and a crushed, recompounded and reformulated tube.

[0107] In another embodiment, said composition of the layer (1) comprises at least one compound chosen from plasticizer, an impact modifier and an additive, and said recycled material is chosen from a crushed tube, then recompounded and reformulated.

[0108] In one embodiment, the fluid transported by said multilayer tube is different from that of said multilayer tubular structure (MLT).

[0109] This means that if the multilayer tube has transported a fluid such as air, said multilayer tubular structure (MLT) may be intended to transport gasoline or, if the multilayer tube has transported a fluid such as alcoholic gasoline, said tubular structure (MLT) may be intended to transport diesel.

[0110] In another embodiment, the fluid transported by said multilayer tube is the same as that of said multilayer tubular structure (MLT).

[0111] This means that if the multilayer tube has transported a fluid such as gasoline, said tubular structure (MLT) may be intended to transport gasoline provided that the gasoline of the multilayer tube and of said multilayer tubular structure (MLT) is the same, for example, alcoholic gasoline.

[0112] Advantageously, the recycled material comes from a multilayer tube such as PAU / / PPA9T and PA12 / / PPA9T or PA11 / / MXD6 and PA12 / / MXD6.

[0113] In one embodiment, said composition of the layer (1) comprises at least 60% by weight, in particular at least 70% by weight, in particular at least 80% by weight, in particular at least 90% by weight, more particularly at least 95% of recycled material.

[0114] In another embodiment, said composition of the layer (1) consists of 100% by weight of recycled material. Recycled used multilayer tube

[0115] In a first variant, said tube which was intended for the transport of automobile fluid is multi-layer and simply crushed and the composition of the layer (1) resulting from said recycling is made up of:

[0116] at least 61% by weight, in particular from 96% to 99% by weight, in particular from 96% to 98% by weight, of at least one semi-crystalline aliphatic polyamide denoted C having an average number of carbon atoms per nitrogen atom denoted Cc of from 6 to 18, advantageously from 8 to 12 and of at least one semi-crystalline semi-aromatic polyamide;

[0117] from 0 to 2% of at least one plasticizer,

[0118] from 0 to 2% by weight of at least one additive, in particular a stabilizer;

[0119] the sum of the constituents being equal to 100%.

[0120] Advantageously, in this first variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10.

[0121] Advantageously in this first variant, said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

[0122] Advantageously, in this first variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10 and said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

[0123] In a second variant, said tube which was intended for the transport of automobile fluid is multi-layered, crushed and recompounded and the composition of the layer (1) resulting from said recycling is made up of:

[0124] at least 61% by weight, in particular from 96% to 99% by weight, in particular from 96% to 98% by weight, of at least one semi-crystalline aliphatic polyamide denoted C having an average number of carbon atoms per nitrogen atom denoted Cc of from 6 to 18, advantageously from 8 to 12, and of at least one semi-crystalline semi-aromatic polyamide;

[0125] from 0 to 2% of at least one plasticizer,

[0126] from 0 to 2% by weight of at least one additive, in particular a stabilizer;

[0127] the sum of the constituents being equal to 100%.

[0128] Advantageously, in this second variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10.

[0129] Advantageously in this second variant, said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

[0130] Advantageously, in this second variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10 and said tube was intended for the transport of fuel such as gasoline, especially alcohol-based gasoline, biogasoline or diesel, especially biodiesel.

[0131] In a third variant, said tube which was intended for the transport of automobile fluid is multi-layered, crushed, recompounded and reformulated and the composition of the layer (1) resulting from said recycling and reformulated is made up of:

[0132] at least 58.5% by weight of at least one semi-crystalline aliphatic polyamide noted C having an average number of carbon atoms per nitrogen atom noted Cc of from 6 to 18, advantageously from 8 to 12 and of at least one semi-crystalline semi-aromatic polyamide;

[0133] from 6 to 14% of at least one plasticizer, in particular from 6 to 8%;

[0134] from 0.5 to 1.5% by weight of at least one additive, in particular a stabilizer;

[0135] the sum of the constituents being equal to 100%.

[0136] Advantageously, in this third variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10.

[0137] Advantageously in this third variant, said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, biogasoline or diesel, in particular biodiesel.

[0138] Advantageously, in this third variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10 and said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

[0139] In a fourth variant, said tube which was intended for the transport of automobile fluid is multi-layered, ground, recompounded and reformulated and the composition of the layer (1) resulting from said recycling and reformulated is made up of:

[0140] at least 58% by weight of at least one semi-crystalline aliphatic polyamide noted C having an average number of carbon atoms per nitrogen atom noted Cc of from 6 to 18, advantageously from 8 to 12 and of at least one semi-crystalline semi-aromatic polyamide;

[0141] from 6 to 14% of at least one plasticizer, in particular from 6 to 8%;

[0142] from 1 to 2% by weight of at least one additive, in particular a stabilizer and a catalyst;

[0143] the sum of the constituents being equal to 100%.

[0144] Advantageously, in this fourth variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and semi-crystalline semi-aromatic polyamide is selected from PA9T, PA10T, PA12T, MXD6 and MXD10.

[0145] Advantageously in this fourth variant, said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, biogasoline or diesel, in particular biodiesel.

[0146] Advantageously, in this fourth variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10 and said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

[0147] Advantageously, the composition is degassed during compounding, even more advantageously the degassing is located just after the melting zone, and before the zone of introduction of plasticizer such as BBSA or other.

[0148] In a fifth variant, said tube which was intended for the transport of fluid for automobiles is multi-layered, crushed, recompounded and reformulated and the composition of the layer (1) resulting from said recycling and reformulated is made up of:

[0149] at least 50% by weight, in particular from 50% to 99% by weight, in particular from 50% to 98% by weight, of at least one semi-crystalline aliphatic polyamide denoted C having an average number of carbon atoms per nitrogen atom denoted Cc of from 6 to 18, advantageously from 8 to 12 and of at least one semi-crystalline semi-aromatic polyamide;

[0150] from 0 to 25% by weight of at least one semi-crystalline aliphatic polyamide noted B and having an average number of carbon atoms per nitrogen atom noted CB = Ce - 1, preferably CB = Ce - 2;

[0151] from 0 to 25% by weight of a semi-crystalline aliphatic polyamide noted A having an average number of carbon atoms per nitrogen atom noted CA = CB - 1, preferably CA = CB - 2;

[0152] from 0 to 2% of at least one plasticizer,

[0153] from 0 to 2% by weight of at least one additive,

[0154] the sum of the constituents being equal to 100%.

[0155] Advantageously, in this fifth variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10.

[0156] Advantageously in this fifth variant, said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, biogasoline or diesel, in particular biodiesel.

[0157] Advantageously, in this fifth variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10 and said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

[0158] In a sixth variant, said tube which was intended for the transport of automobile fluid is multi-layered, ground, recompounded and reformulated and the composition of the layer (1) resulting from said recycling and reformulated is made up of:

[0159] at least 55% by weight, in particular from 55% to 99% by weight, in particular from 55% to 98% by weight, of at least one semi-crystalline aliphatic polyamide denoted C having an average number of carbon atoms per nitrogen atom denoted Cc of from 6 to 18, advantageously from 8 to 12 and of at least one semi-crystalline semi-aromatic polyamide;

[0160] from 0 to 45% by weight of at least one impact modifier, in particular from 1 to 45% by weight of at least one impact modifier, in particular from 2 to 45% by weight of at least one impact modifier,

[0161] the sum of the constituents being equal to 100%.

[0162] Advantageously, in this sixth variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10.

[0163] Advantageously in this sixth variant, said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

[0164] Advantageously, in this sixth variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10 and said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

[0165] In a seventh variant, said tube which was intended for the transport of automobile fluid is multi-layered, ground, recompounded and reformulated and the composition of the layer (1) resulting from said recycling and reformulated is made up of:

[0166] at least 50% by weight of at least one semi-crystalline aliphatic polyamide noted C having an average number of carbon atoms per nitrogen atom noted Cc of from 6 to 18, advantageously from 8 to 12 and of at least one semi-crystalline semi-aromatic polyamide;

[0167] from 0 to 43.5% by weight of at least one impact modifier, in particular from 1 to 43.5% by weight of at least one impact modifier, in particular from 2 to 43.5% by weight of at least one impact modifier,

[0168] from 6 to 14% of at least one plasticizer, in particular from 6 to 8%;

[0169] from 0.5 to 1.5% by weight of at least one additive, in particular a stabilizer;

[0170] the sum of the constituents being equal to 100%.

[0171] Advantageously, in this seventh variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10.

[0172] Advantageously in this seventh variant, said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

[0173] Advantageously, in this seventh variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10 and said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

[0174] In an eighth variant, said tube which was intended for the transport of automobile fluid is multi-layered, ground, recompounded and reformulated and the composition of the layer (1) resulting from said recycling and reformulated is made up of:

[0175] at least 50% by weight of at least one semi-crystalline aliphatic polyamide noted C having an average number of carbon atoms per nitrogen atom noted Cc of from 6 to 18, advantageously from 8 to 12 and of at least one semi-crystalline semi-aromatic polyamide;

[0176] from 0 to 43% by weight of at least one impact modifier, in particular from 1 to 43% by weight of at least one impact modifier, in particular from 2 to 38% by weight of at least one impact modifier,

[0177] from 6 to 14% of at least one plasticizer, in particular from 6 to 8%;

[0178] from 1 to 2% by weight of at least one additive, in particular a stabilizer and a catalyst;

[0179] the sum of the constituents being equal to 100%.

[0180] Advantageously, in this eighth variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10.

[0181] Advantageously in this eighth variant, said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

[0182] Advantageously, in this eighth variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10 and said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

[0183] In a ninth variant, said tube which was intended for the transport of automobile fluid is multi-layered, ground, recompounded and reformulated and the composition of the layer (1) resulting from said recycling and reformulated is made up of:

[0184] at least 50% by weight of at least one semi-crystalline aliphatic polyamide noted C having an average number of carbon atoms per nitrogen atom noted Cc of from 6 to 18, advantageously from 8 to 12 and of at least one semi-crystalline semi-aromatic polyamide;

[0185] from 0 to 25% by weight of at least one semi-crystalline aliphatic polyamide noted B and having an average number of carbon atoms per nitrogen atom noted CB = Ce - 1, preferably CB = Ce - 2;

[0186] from 0 to 25% by weight of a semi-crystalline aliphatic polyamide noted A having an average number of carbon atoms per nitrogen atom noted CA = CB - 1, preferably CA = CB - 2;

[0187] from 0 to 43% by weight of at least one impact modifier, in particular from 1 to 43% by weight of at least one impact modifier, in particular from 2 to 38% by weight of at least one impact modifier,

[0188] from 0 to 20% of at least one plasticizer,

[0189] from 0 to 2% by weight of at least one additive,

[0190] the sum of the constituents being equal to 100%.

[0191] Advantageously, in this ninth variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10.

[0192] Advantageously in this ninth variant, said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, biogasoline or diesel, in particular biodiesel.

[0193] Advantageously, in this ninth variant, the semi-crystalline aliphatic polyamide denoted C is chosen from PA612, PA 1012, PA 1010, PAU and PA 12, in particular PA11 and the semi-crystalline semi-aromatic polyamide is chosen from PA9T, PA10T, PA12T, MXD6 and MXD10 and said tube was intended for the transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel. Regarding the shock modifier

[0194] The impact modifier is advantageously constituted by a polymer having a flexural modulus of less than 100 MPa measured according to standard ISO 178: 2010, determined at 23°C with a relative humidity: RH50%, and a Tg of less than 0°C (measured according to standard 11357-2: 2013 at the inflection point of the DSC thermogram, at a heating rate of 20K / min), in particular a polyolefin.

[0195] The polyolefin of the impact modifier may be functionalized or non-functionalized or be a mixture of at least one functionalized and / or at least one non-functionalized. For simplicity, the polyolefin has been designated (B) and functionalized polyolefins (B1) and non-functionalized polyolefins (B2) have been described below.

[0196] A non-functionalized polyolefin (B2) is typically a homopolymer or copolymer of alpha olefins or diolefins, such as, for example, ethylene, propylene, butene-1, octene-1, butadiene. By way of example, mention may be made of:

[0197] - homopolymers and copolymers of polyethylene, in particular LDPE, HDPE, LLDPE (linear low density polyethylene), VLDPE (very low density polyethylene) and metallocene polyethylene.

[0198] - homopolymers or copolymers of propylene.

[0199] - ethylene / alpha-olefin copolymers such as ethylene / propylene, EPR (short for ethylene-propylene-rubber) and ethylene / propylene / diene rubber (EPDM).

[0200] - styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / block copolymers styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS).

[0201] - copolymers of ethylene with at least one product chosen from salts or esters of unsaturated carboxylic acids such as alkyl (meth)acrylate (e.g. methyl acrylate), or vinyl esters of saturated carboxylic acids such as vinyl acetate (EVA), the proportion of comonomer being up to 40% by weight.

[0202] The functionalized polyolefin (B1) may be a polymer of alpha olefins having reactive units (the functionalities); such reactive units are acid, anhydride, or epoxy functions. By way of example, mention may be made of the preceding polyolefins (B2) grafted or co- or terpolymerized by unsaturated epoxides such as glycidyl (meth)acrylate, or by carboxylic acids or the corresponding salts or esters such as (meth)acrylic acid (the latter being able to be neutralized totally or partially by metals such as Zn, etc.) or even by carboxylic acid anhydrides such as maleic anhydride. A functionalized polyolefin is, for example, a PE / EPR blend, the weight ratio of which can vary widely, for example between 40 / 60 and 90 / 10, said blend being co-grafted with an anhydride, in particular maleic anhydride, according to a grafting rate of, for example, 0.01 to 5% by weight.

[0203] The functionalized polyolefin (Bl) can be chosen from the following (co)polymers, grafted with maleic anhydride or glycidyl methacrylate, in which the grafting rate is for example from 0.01 to 5% by weight:

[0204] - PE, PP, copolymers of ethylene with propylene, butene, hexene, or octene containing for example from 35 to 80% by weight of ethylene;

[0205] - ethylene / alpha-olefin copolymers such as ethylene / propylene, EPR (short for ethylene-propylene-rubber) and ethylene / propylene / diene rubber (EPDM).

[0206] - styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / block copolymers styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS).

[0207] - ethylene and vinyl acetate (EVA) copolymers, containing up to 40% in vinyl acetate weight;

[0208] - ethylene and alkyl (meth)acrylate copolymers, containing up to 40% in weight of alkyl (meth)acrylate;

[0209] - ethylene and vinyl acetate (EVA) and alkyl (meth)acrylate copolymers, containing up to 40% by weight of comonomers.

[0210] The functionalized polyolefin (Bl) can also be chosen from ethylene / propylene copolymers with a majority of propylene grafted with maleic anhydride then condensed with mono-amine polyamide (or a polyamide oligomer) (products described in EP-A-0342066).

[0211] The functionalized polyolefin (Bl) may also be a co- or terpolymer of at least the following units: (1) ethylene, (2) alkyl (meth)acrylate or saturated carboxylic acid vinyl ester and (3) anhydride such as maleic anhydride or (meth)acrylic acid or epoxy such as glycidyl (meth)acrylate.

[0212] As examples of functionalized polyolefins of the latter type, the following copolymers may be mentioned, where ethylene preferably represents at least 60% by weight and where the ter monomer (the function) represents, for example, from 0.1 to 10% by weight of the copolymer:

[0213] - ethylene / alkyl (meth)acrylate / (meth)acrylic acid copolymers or maleic anhydride or glycidyl methacrylate;

[0214] - ethylene / vinyl acetate / maleic anhydride or methacrylate copolymers glycidyl;

[0215] - ethylene / vinyl acetate or alkyl (meth)acrylate / acid copolymers (meth)acrylic or maleic anhydride or glycidyl methacrylate.

[0216] In the preceding copolymers, the (meth)acrylic acid can be salified with Zn or Li.

[0217] The term "alkyl (meth)acrylate" in (B1) or (B2) denotes C1-C8 alkyl methacrylates and acrylates, and may be selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, methyl methacrylate and ethyl methacrylate.

[0218] Furthermore, the aforementioned polyolefins (B 1) can also be crosslinked by any suitable process or agent (diepoxy, diacid, peroxide, etc.); the term functionalized polyolefin also includes mixtures of the aforementioned polyolefins with a difunctional reagent such as diacid, dianhydride, diepoxy, etc. capable of reacting with them or mixtures of at least two functionalized polyolefins capable of reacting with each other.

[0219] The above-mentioned copolymers, (B1) and (B2), can be copolymerized in a random or block manner and have a linear or branched structure.

[0220] The molecular weight, MFI index, and density of these polyolefins can also vary to a large extent, which those skilled in the art will appreciate. MFI, short for Melt Flow Index, is the melt flow index. It is measured according to ASTM 1238.

[0221] Advantageously, the non-functionalized polyolefins (B2) are chosen from homopolymers or copolymers of polypropylene and any homopolymer of ethylene or copolymer of ethylene and a comonomer of higher alpha olefin type such as butene, hexene, octene or 4-methyl 1-pentene. Examples that may be mentioned are PP, high density PE, medium density PE, linear low density PE, low density PE, very low density PE. These polyethylenes are known to those skilled in the art as being produced according to a “radical” process, according to a “Ziegler” type catalysis or, more recently, according to a so-called “metallocene” catalysis.

[0222] Advantageously, the functionalized polyolefins (B1) are chosen from any polymer comprising alpha olefinic units and units carrying polar reactive functions such as epoxy, carboxylic acid or carboxylic acid anhydride functions. Examples of such polymers that may be mentioned are terpolymers of ethylene, alkyl acrylate and maleic anhydride or glycidyl methacrylate such as the Applicant's Lotader® or polyolefins grafted with maleic anhydride such as the Applicant's Orevac® as well as terpolymers of ethylene, alkyl acrylate and (meth)acrylic acid. Mention may also be made of homopolymers or copolymers of polypropylene grafted with a carboxylic acid anhydride and then condensed with polyamides or monoamine oligomers of polyamide. Regarding additives

[0223] The additives optionally used in the compositions of the invention are the conventional additives used in polyamides well known to those skilled in the art and are notably described in EP 2098580.

[0224] For example, they are chosen from a catalyst, an antioxidant, a heat stabilizer, a UV absorber, a light stabilizer, a lubricant, an inorganic filler, a flame retardant, a nucleating agent and a colorant, reinforcing fibers, a wax and mixtures thereof.

[0225] The term "catalyst" means a polycondensation catalyst such as a mineral or organic acid.

[0226] Advantageously, the proportion by weight of catalyst is from approximately 50 ppm to approximately 5000 ppm, in particular from approximately 100 to approximately 3000 ppm relative to the total weight of the composition.

[0227] Advantageously, the catalyst is chosen from phosphoric acid (H3PO4), phosphorous acid (H3PO3), hypophosphorous acid (H3PO2), or a mixture thereof.

[0228] For example, the stabilizer may be a UV stabilizer, an organic stabilizer or more generally a combination of organic stabilizers, such as a phenol-type antioxidant (for example of the type of irganox® 245 or 1098 or 1010 from the company Ciba-BASF), a phosphite-type antioxidant (for example irgafos® 126 and irgafos® 168 from the company Ciba-BASF) and possibly other stabilizers such as a HALS, which means Hindered Amine Light Stabilizer or hindered amine light stabilizer (for example Tinuvin® 770 from the company Ciba-BASF), an anti-UV (for example Tinuvin® 312 from the company Ciba) or a phosphorus-based stabilizer. It is also possible to use amine-type antioxidants such as Naugard® 445 from Crompton or polyfunctional stabilizers such as Nylostab® S-EED from Clariant.

[0229] This stabilizer may also be a mineral stabilizer, such as a copper-based stabilizer. Examples of such mineral stabilizers include copper halides and acetates. Alternatively, other metals such as silver may be considered, but these are known to be less effective. These copper-based compounds are typically combined with alkali metal halides, particularly potassium. Regarding the plasticizer

[0230] The plasticizers are, for example, the plasticizers are selected from benzene sulfonamide derivatives, such as n-butyl benzene sulfonamide (BBSA); ethyl toluene sulfonamide or N-cyclohexyl toluene sulfonamide; hydroxybenzoic acid esters, such as ethyl-2-hexyl parahydroxybenzoate and decyl-2-hexyl parahydroxybenzoate; esters or ethers of tetrahydrofurfuryl alcohol, such as oligoethyleneoxytetrahydrofurfuryl alcohol; and esters of citric acid or hydroxymalonic acid, such as oligoethyleneoxy malonate.

[0231] It would not be outside the scope of the invention to use a mixture of plasticizers.

[0232] The additives when present in the composition are advantageously present from 1 to 20% by weight, in particular from 5 to 15% by weight, in particular from 5 to 12% by weight. Regarding antistatic charges

[0233] The antistatic fillers are for example chosen from carbon black, graphite, carbon fibers, carbon nanotubes, in particular carbon black and carbon nanotubes. Regarding layer (2)

[0234] The terms “semi-crystalline polyamide” and “aliphatic” have the same definition as for layer (1).

[0235] Said at least one aliphatic semi-crystalline polyamide is obtained in the same manner as described above for layer (1).

[0236] In a first variant of the layer (2), said layer (2) is devoid of impact modifier.

[0237] In this case, the semi-crystalline aliphatic polyamide which is PA12 or PA612 or PA1010 is excluded from the composition which constitutes the layer (2).

[0238] In a second variant of the layer (2), said layer (2) comprises from 3 to 45% by weight of at least one impact modifier, in particular from 5 to 20% by weight of at least one impact modifier.

[0239] In one embodiment of this second variant, said layer (2) consists of a composition comprising:

[0240] at least 50% by weight, in particular from 50% to 97% by weight, in particular from 50% to 95% by weight, of at least one semi-crystalline aliphatic polyamide denoted D having an average number of carbon atoms per nitrogen atom denoted CD of from 6 to 18, advantageously from 9 to 15;

[0241] from 0 to 25% by weight of at least one semi-crystalline aliphatic polyamide noted E and having an average number of carbon atoms per nitrogen atom noted CE = CD - 1, preferably CE = CD - 2;

[0242] from 0 to 25% by weight of a semi-crystalline aliphatic polyamide noted F having an average number of carbon atoms per nitrogen atom noted CE = CE - 1, preferably CE = CE - 2;

[0243] from 3 to 45% by weight of at least one impact modifier, in particular from 5 to 20% by weight of at least one impact modifier;

[0244] from 0 to 20% of at least one plasticizer;

[0245] from 0 to 2% by weight of at least one additive,

[0246] from 0 to 35% of at least one antistatic filler,

[0247] the sum of the constituents being equal to 100%.

[0248] In another embodiment of this second variant, said layer (2) is made up of a composition consisting of:

[0249] at least 50% by weight, in particular from 50% to 97% by weight, in particular from 50% to 95% by weight, of at least one semi-crystalline aliphatic polyamide denoted D having an average number of carbon atoms per nitrogen atom denoted CD of from 6 to 18, advantageously from 9 to 15;

[0250] from 0 to 25% by weight of at least one semi-crystalline aliphatic polyamide noted E and having an average number of carbon atoms per nitrogen atom noted CE = CD - 1, preferably CE = CD - 2;

[0251] from 0 to 25% by weight of a semi-crystalline aliphatic polyamide noted F having an average number of carbon atoms per nitrogen atom noted CE = CE - 1, preferably CE = CE - 2;

[0252] from 3 to 45% by weight of at least one impact modifier, in particular from 5 to 20% by weight of at least one impact modifier;

[0253] from 0 to 20% of at least one plasticizer;

[0254] from 0 to 2% by weight of at least one additive,

[0255] from 0 to 35% of at least one antistatic filler,

[0256] the sum of the constituents being equal to 100%.

[0257] Advantageously, the composition of said layer (2) comprises a PAU, a PA12 or a PA612 and from 3 to 45% by weight of an impact modifier, in particular from 5 to 20% by weight of an impact modifier. Regarding layer (2')

[0258] The terms “semi-crystalline polyamide” and “aliphatic” have the same definition as for layer (1) or layer (2).

[0259] Said at least one aliphatic semi-crystalline polyamide is obtained in the same manner as described above for layer (1) and layer (2).

[0260] In a first variant of the layer (2'), said layer (2') is devoid of impact modifier.

[0261] In a second variant of the layer (2'), said layer (2') comprises from 3 to 45% by weight of at least one impact modifier, in particular from 5 to 20% by weight of at least one impact modifier.

[0262] In one embodiment of this second variant, said layer (2') consists of a composition comprising:

[0263] at least 50% by weight, in particular from 50% to 97% by weight, in particular from 50% to 95% by weight, of at least one semi-crystalline aliphatic polyamide noted D having an average number of carbon atoms per nitrogen atom noted CD of from 6 to 18, advantageously from 9 to 15;

[0264] from 0 to 25% by weight of at least one semi-crystalline aliphatic polyamide noted E and having an average number of carbon atoms per nitrogen atom noted CE = CD - 1, preferably CE = CD - 2;

[0265] from 0 to 25% by weight of a semi-crystalline aliphatic polyamide noted F having an average number of carbon atoms per nitrogen atom noted CE = CE - 1, preferably CE = CE - 2;

[0266] from 3 to 45% by weight of at least one impact modifier, in particular from 5 to 20% by weight of at least one impact modifier;

[0267] from 0 to 20% of at least one plasticizer;

[0268] from 0 to 2% by weight of at least one additive,

[0269] from 0 to 35% of at least one antistatic filler,

[0270] the sum of the constituents being equal to 100%.

[0271] In another embodiment of this second variant, said layer (2') is made up of a composition consisting of:

[0272] at least 50% by weight, in particular from 50% to 97% by weight, by weight, in particular from 50% to 95% by weight, of at least one semi-crystalline aliphatic polyamide noted D having an average number of carbon atoms per nitrogen atom noted CD of from 6 to 18, advantageously from 9 to 15;

[0273] from 0 to 25% by weight of at least one semi-crystalline aliphatic polyamide noted E and having an average number of carbon atoms per nitrogen atom noted CE = CD - 1, preferably CE = CD - 2;

[0274] from 0 to 25% by weight of a semi-crystalline aliphatic polyamide noted F having an average number of carbon atoms per nitrogen atom noted CF = CE - 1, preferably CF = CE - 2;

[0275] from 3 to 45% by weight of at least one impact modifier, in particular from 5 to 20% by weight of at least one impact modifier;

[0276] from 0 to 20% of at least one plasticizer;

[0277] from 0 to 2% by weight of at least one additive,

[0278] from 0 to 35% of at least one antistatic filler,

[0279] the sum of the constituents being equal to 100%.

[0280] Advantageously, the composition of said layer (2') comprises a PAU, a PA12 or a PA612 and from 3 to 45% by weight of at least one impact modifier, in particular from 5 to 20% by weight of at least one impact modifier. Regarding the structure

[0281] All embodiments of layer (1) described above in the paragraph "regarding layer (1)" can be used for the structure detailed in this part.

[0282] In one embodiment, said layer (1) is located between a layer (2) and a layer (2').

[0283] Advantageously, said layer (2') is the layer in contact with the transported fluid.

[0284] Advantageously, said layer (2') is as defined for layer (2), and preferably layers (2) and (2') are identical.

[0285] In this latter embodiment, said layer (2') is as defined for layer (2) meaning that the compositions of layer (2) and layer (2') may be identical or different.

[0286] When they are different, they may differ by the polyamide or the proportion of polyamide or by one of the other constituents of the composition.

[0287] Advantageously, the composition of said layer (2) comprises a PAU, a PA12 or a PA612 and the recycled material comes from a multilayer tube consisting of a composition comprising a PA11 or a PA12 and a PA9T, PA10T, PA12T, PAMXD6 and PAMXD10, in particular the composition of the layer (1) consists of 100% recycled material.

[0288] Advantageously, the composition of said layer (2) comprises a PAU, a PA12 or a PA612, the recycled material comes from a multilayer tube consisting of a composition comprising a PA11 or a PA12 and a PA9T, PA10T, PA12T, PAMXD6 and PAMXD10, in particular the composition of the layer (1) consists of 100% of recycled material and the composition of said layer (2') comprises a PAU, a PA12 or a PA612.

[0289] Advantageously, the composition of said layer (2) comprises a PAU, a PA12 or a PA612 and from 3 to 45% by weight of at least one impact modifier, in particular from 5 to 20% by weight of at least one impact modifier and the recycled material comes from a multilayer tube consisting of a composition comprising a PA11 or a PA12 and a PA9T, PA10T, PA12T, PAMXD6 and PAMXD10, in particular the composition of the layer (1) consists of 100% recycled material.

[0290] Advantageously, the composition of said layer (2) comprises a PAU, a PA12 or a PA612 and from 3 to 45% by weight of at least one impact modifier, in particular from 5 to 20% by weight of at least one impact modifier and the recycled material comes from a multilayer tube consisting of a composition comprising a PA11 or a PA12 and a PA9T, PA10T, PA12T, PAMXD6 and PAMXD10, in particular the composition of the layer (1) consists of 100% recycled material and the composition of said layer (2') comprises a PAU, a PA12 or a PA612 and from 3 to 45% by weight of at least one impact modifier, in particular from 5 to 20% by weight of at least one impact modifier.

[0291] Advantageously, the compositions of layer (2) and layer (2') are identical and therefore layers (2) and (2') are obviously identical, that is to say that both the polyamide and the other constituents of the composition are identical in nature and proportion and that the thickness of the two layers (2) and (2') is identical. Layer (2') is then a layer (2).

[0292] In a first variant of the multi-layer tubular structure (MLT), it is made up of three layers (2) / / (1) / / (2'), in particular (2) / / (1) / / (2).

[0293] In one embodiment, at least one binder layer (3) is present, said layer (3) being located between layer (2) and layer (1) and / or between layer (1) and layer (2').

[0294] In a second variant of the multi-layer tubular structure (MLT), this is made up of four layers (2) / / binder (3) / / (l) / / (2'), in particular (2) / / binder (3) / / (1) / / (2).

[0295] In a third variant of the multi-layer tubular structure (MLT), this consists of four layers (2) / / (1) / / binder (3) / / (2'), in particular (2) / / (1) / / binder (3) / / (2).

[0296] In a fourth variant of the multi-layer tubular structure (MLT), this consists of five layers (2) / / binder (3) / / (1) / / binder (3) / / (2'), in particular (2) / / binder (3) / / (1) / / binder (3) / / (2).

[0297] In this fourth variant, the two layers of binder (3) may be identical or different, in particular they are identical.

[0298] In another embodiment, at least one layer of EVOH is present, said layer (3) being located between layer (1) and layer (2').

[0299] The multi-layer tubular structure (MLT) is then made up of four layers

[0300] (2) / / ( 1 ) / / EVOH / / (2' ), in particular (2) / / ( 1 ) / / EVOH / / (2).

[0301] In one embodiment, said layer (1) represents at least 10%, in in particular at least 30%, in particular at least 50% of the total thickness of said multi-layer tubular structure (MLT).

[0302] Advantageously, said layer (1) represents at least 60%, in particular at least 70% of the total thickness of said multilayer tubular structure (MLT).

[0303] In one embodiment of one of the four variants of the multilayer tubular structure (MLT) or of the four-layer structure with EVOH, said composition of said layer (1) is free of polyamides noted A and B and said composition of said layer (2) comprises polyamides chosen from those noted E, F and a mixture thereof.

[0304] In another embodiment of one of the four variants of the multilayer tubular structure (MLT) or of the four-layer structure with EVOH, said composition of said layer (1) comprises polyamides chosen from those noted A, B and a mixture thereof, and said composition of said layer (2) is free of polyamides noted E and F.

[0305] In yet another embodiment of one of the four variants of the multilayer tubular structure (MLT) or of the four-layer structure with EVOH, said composition of said layer (1) comprises polyamides chosen from those denoted A, B and a mixture thereof, and said composition of said layer (2) comprises polyamides chosen from those denoted E, F and a mixture thereof.

[0306] In yet another embodiment of one of the four variants of the multilayer tubular structure (MLT) or of the four-layer structure with EVOH, said composition of said layer (1) is free of polyamides noted A and B and said composition of said layer (2) is free of polyamides noted E and F.

[0307] Advantageously, in these last four embodiments, the layer (1) comes from a recycled multi-layer tube.

[0308] Advantageously, in these last four embodiments, the layer (1) comes from a recycled multilayer tube and only said composition of said layer (1) comprises at least one impact modifier.

[0309] Advantageously, in these last four embodiments, the layer (1) comes from a recycled multi-layer tube and said composition of said layer (1) as well as said compositions of the layer (2) and of the layer (2') comprise at least one impact modifier.

[0310] In one embodiment, said multi-layer tubular (MLT) is intended for the transport of fluids chosen from a fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel. As regards the binder

[0311] The binder is notably described in patents EP1452307 and EPI 162061, EP1216826, EP0428833 and EP3299165.

[0312] It is implied that layers (2) and (1) or (1) and (2') adhere to each other. The binder layer is intended to be inserted between two layers which do not adhere or adhere with difficulty to each other.

[0313] The binder may be, for example, but not limited to, a composition based on 50% copolyamide 6 / 12 (70 / 30 ratio by mass) of Mn 16000, and 50% copolyamide 6 / 12 (30 / 70 ratio by mass) of Mn 16000, a composition based on PP (polypropylene) grafted with maleic anhydride, known under the name Admer QF551A from the company Mitsui, a composition based on PA610 (of Mn 30000, and as defined elsewhere) and 36% PA6 (of Mn 28000) and 1.2% organic stabilizers (consisting of 0.8% Lowinox 44B25 phenol from the company Great Lakes, 0.2% phosphite Irgafos 168 from Ciba, 0.2% anti-UV Tinuvin 312 from Ciba), a composition based on PA612 (of Mn 29000, and as defined elsewhere) and 36% PA6 (of Mn 28000, and as defined elsewhere) and 1.2% organic stabilizers (consisting of 0.8% phenol Lowinox 44B25 from Great Lakes, 0.2% phosphite Irgafos 168 from Ciba, 0.2% of anti-UV Tinuvin 312 from the company Ciba), a composition based on PA610 (of Mn 30000, and as defined elsewhere) and 36% of PA12 (of Mn 35000, and as defined elsewhere) and 1.2% of organic stabilizers (consisting of 0.8% of phenol Lowinox 44B25 from the company Great Lakes, 0.2% of phosphite Irgafos 168 from the company Ciba, 0.2% of anti-UV Tinuvin 312 from the company Ciba), a composition based on 40% PA6 (of Mn 28000, and as defined elsewhere), 40% of PA12 (of Mn 35000, and as defined elsewhere) and 20% of functionalized EPR Exxelor VA1801 (Exxon company) and 1.2% organic stabilizers (consisting of 0.8% Lowinox 44B25 phenol from Great Lakes company, 0.2% Irgafos 168 phosphite from Ciba company, 0.2% Tinuvin 312 UV inhibitor from Ciba company) or a composition based on 40% PA6.10 (of Mn 30000, and as defined elsewhere), 40% of PA6 (of Mn 28000, and as defined elsewhere) and 20% of ethylene / ethyl acrylate / anhydride type impact modifier in a mass ratio of 68.5 / 30 / 1.5 (MFI 6 at 190°C under 2.16 kg), and 1.2% of organic stabilizers (consisting of 0.8% of Lowinox 44B25 phenol from Great Lakes, 0.2% of Irgafos 168 phosphite from Ciba, 0.2% of Tinuvin 312 UV inhibitor from Ciba). EXAMPLES#:

[0314] The following resins were used in the various compositions of the invention:

[0315] PA11: Polyamide 11 of Mn (number molecular weight) 29000. The melting temperature is 190°C, its enthalpy of fusion is 56kJ / m2. The composition of this PAU includes 0.25% (+ / -0.05%) of H3PO4.

[0316] PA12: Polyamide 12 of Mn (number molecular weight) 35000. The melting temperature is 178°C, its enthalpy of fusion is 54kJ / m2

[0317] PA12-B: Polyamide 12 of Mn (number molecular weight) 41000. The melting temperature is 178°C, its enthalpy of fusion is 54kJ / m2

[0318] PA1012: Polyamide 1012 of Mn (number-average molecular weight) 27000. The melting temperature is 190°C, its enthalpy of fusion is 57kJ / m2

[0319] PA612: Polyamide 612 of Mn (number-average molecular weight) 29000. The melting temperature is 218°C, its enthalpy of fusion is 67kJ / m2

[0320] PA610: Polyamide 610 of Mn (number-average molecular weight) 30000. The melting temperature is 223°C, its enthalpy of fusion is 61kJ / m2

[0321] PA6: Polyamide 6 of Mn (number molecular weight) 28000. The melting temperature is 220°C, its enthalpy of fusion is 68kJ / m2

[0322] The melting temperature and enthalpy of fusion were determined according to ISO 11357-3:2013.

[0323] The following additives, plasticizers and impact modifiers were used in the compositions of the invention:

[0324] stabilizer: stabilizer consisting of 80% Lowinox 44B25 phenol from Great Lakes, 20% Irgafos 168 phosphite from Ciba

[0325] BBSA: plasticizer BBSA (benzyl butyl sulfonamide),

[0326] Imod = generically designates an impact modifier of polyolefin type or other such as PEBA (polyether-block-amide), core-shell, silicones, etc.

[0327] Imodl: designates an EPR functionalized by a reactive anhydride functional group (at 0.5-1% by mass), of MFI 9 (at 230°C, under) 10kg, of the Exxellor VA1801 type from the Exxon company.

[0328] Imod2: impact modifier type ethylene / ethyl acrylate / anhydride in mass ratio 68.5 / 30 / 1.5 and MFI 6 at 190°C under 2.16 kg.

[0329] Imod3: impact modifier type ethylene / butyl acrylate / anhydride in mass ratio 79 / 18 / 3 and MFI 5 at 190°C under 2.16 kg.

[0330] The following compositions were used to manufacture the tubes according to the invention:

[0331] Throughout the description all percentages are given by weight.

[0332] In the case of the compositions called “recy”, “recy2” and “recy3” used for layer (1) of the tubes of the invention or the counter-example tubes, protocols for simulating an aged tube were used:

[0333] Protocol A: The tube is (artificially) aged according to an easily reproducible model protocol which consists of placing it in air (in the presence of oxygen) at 150°C for 96 hours (4 days), in order to thermo-oxidize it. This model aging is representative of the average thermo-oxidation that the tubes undergo in 10 years of service in a vehicle next to a hot engine.

[0334] The results obtained on impact, aging, flexural modulus, adhesion and elongation show that protocol A is representative of a reground gasoline tube.

[0335] Special protocols used during (re)compounding of the aged tube.

[0336] After aging the crushed tube can in certain cases be recompounded according to two protocols:

[0337] Protocol B: the reground tube is recompounded on a Coperion / Wemer 40mm twin-screw extruder, 70kgh, 300rpm, 270°C setpoint, with degassing of -100mmHg.

[0338] Protocol B2: the reground tube is recompounded on a Coperion / Wemer 40mm twin-screw extruder, 70kgh, 300rpm, 270°C setpoint, with strong degassing of -660mmHg.

[0339] The different compositions used for the preparation of the tubes of the invention are as follows:

[0340] PA11PL = PA11 + 7% BBSA + 1% stabilizer

[0341] PA12PL = PA12 + 12% BBSA + 1% stabilizer

[0342] PA1 IPL-recy = PA11PL tube aged according to protocol A, reground, to then be recycled.

[0343] PA1 lPL-recy2 = PA11PL tube aged according to protocol A, reground, recompounded according to protocol B2, with during this recompounding addition of 7% BBSA + 0.5%stab, to then be recycled

[0344] PA1 IPL-recy + 50%PA12PL-recy = a 50 / 50 mixture of PA1 IPL-recy and PA12PL-recy granules.

[0345] 1012-recy = PA1012PL4 tube aged according to protocol A, reground, to then be recycled

[0346] PA11PL4 = PA11 + 12% BBSA + 1% stabilizer

[0347] PA12HIP-recy3 = PA12HIPHL tube aged according to protocol A, reground, recompounded according to protocol B, with during this recompounding addition of 6%hnodl, 9%BBSA and 1% stab; then intended to be recycled

[0348] 11NX3 = PA11 + imod2 10% + PA610 5% + PA6 5% + BBSA 4% + stabilizer 1%

[0349] PA1 IPL-recy +50%PAl 1PL = a 50 / 50 blend of PA1 IPL-recy and PA11PL granules, recycled material and virgin material

[0350] PA12HIPHL= PA12 + 6% imodl + 10%BBSA + l% stabilizer

[0351] PA12HIPHL-recy = PA12HIPHL tube aged according to protocol A, reground, to then be recycled

[0352] PA12HIPHL-recy2 = PA12HIPHL tube aged according to protocol A, reground, recompounded according to protocol B, with during this recompounding addition of 10% of BBS A + 0.5% of stabilizer, to then be recycled

[0353] PA12HIP-recy3 = PA12HIPHL tube aged according to protocol A, reground, recompounded according to protocol B, with during this recompounding addition of 6%imodl, 9%BBSA and 1% stab; then intended to be recycled

[0354] MLT-cxl 1-recy = MLT tube (11NX3 / / OHhi / / 11NX3 45 / / 15 / / 40%) aged according to protocol A, reground, recompounded according to protocol B, to then be recycled

[0355] MLT-cx21-recy = MLT tube (11NX3 / / MXD6hi 80 / 20%) aged according to protocol A, reground, recompounded according to protocol B, to then be recycled

[0356] MXD6hi = impact-modified MXD6 composition = composition based on an MXD6-type copolyamide with an impact modifier, marketed under the name BXT-2000 by Solvay. Its melting point is 237°C.

[0357] MLT-cxl 1-recy + 20% MLTcx31-recy = is a mixture of 80% MLT-cxl 1-recy and 20% MLT-cx31-recy

[0358] MLT-cx31-recy = MLT tube (PA12HI2 / / PA1 l-recyNX3 / / PPA9T 15 / 60 / 25%) aged according to protocol A, reground, recompounded according to protocol B, to then be recycled

[0359] PA12HI2 = PA12-B + 10%imodl + 5% BBSA + 1% stabilizer

[0360] OHhi = shock modified EVOH, marketed under the name EVAL LA170B by the company Eval-Kuraray

[0361] These compositions are manufactured by conventional compounding in a co-rotating twin-screw extruder of the Coperion 40 type, at 300 rpm, at 270°C (or at 300°C when the ingredients have a melting point above 260°C). Multilayer tubes of the invention#:

[0362] The layers are described from the outside to the inside, followed by their respective thicknesses indicated in the form of %; the tubes are of dimension 8 * 1mm

[0363] Preparation of multilayer structures (tubes):

[0364] Multilayer tubes are produced by coextrusion. A Maillefer industrial multilayer extrusion line is used, equipped with 5 extruders, connected to a multilayer extrusion head with spiral mandrels.

[0365] The screws used are single-screw extrusions with screw profiles adapted to polyamides. In addition to the 5 extruders and the multi-layer extrusion head, the extrusion line includes:

[0366] a die-punch assembly, located at the end of the coextrusion head; the internal diameter of the die and the external diameter of the punch are chosen according to the structure to be produced and the materials which compose it, as well as the dimensions of the tube and the line speed;

[0367] a vacuum tank with an adjustable depression level. In this tank circulates water maintained at 20°C in general, in which a gauge is immersed to conform the tube to its final dimensions. The diameter of the gauge is adapted to the dimensions of the tube to be produced, typically from 8.5 to 10 mm for a tube with an external diameter of 8 mm and a thickness of 1 mm;

[0368] a succession of cooling tanks in which water is maintained at around 20°C, allowing the tube to be cooled along the route from the head to the drawing bench;

[0369] a diameter meter;

[0370] a drawing bench.

[0371] The 5-extruder configuration is used to produce tubes ranging from 2 layers to 5 layers (and also single-layer tubes). In the case of structures with fewer than 5 layers, several extruders are then fed with the same material.

[0372] Before the tests, in order to ensure the best tube properties and good extrusion quality, it is checked that the extruded materials have a residual moisture content before extrusion of less than 0.08%. Otherwise, an additional step of drying the material is carried out before the tests, generally in a vacuum dryer, for 1 night at 80°C.

[0373] The tubes, which meet the characteristics described in the present patent application, were taken, after stabilization of the extrusion parameters, the dimensions of the tubes targeted no longer changing over time. The diameter is controlled by a laser diameter meter installed at the end of the line.

[0374] The line speed is typically 20m / min. It generally varies between 5 and 100m / min.

[0375] The screw speed of the extruders depends on the layer thickness and the screw diameter as is known to those skilled in the art.

[0376] Generally speaking, the temperatures of the extruders and the tools (head and connector) must be adjusted so as to be sufficiently higher than the melting temperature of the compositions in question, so that they remain in the molten state, thus preventing them from solidifying and blocking the machine.

[0377] The multilayer tubes produced by extrusion above were then evaluated on several criteria:

[0378] Flex.: designates the flexural modulus measured according to ISO178 at 23°C on a tube conditioned at equilibrium in a 50% humidity climate and at 23°C

[0379] We note a flexibility that can be described as "good", which corresponds to <= 1000 MPa and > 500 MPa

[0380] We note a flexibility that can be described as "very good", which corresponds to <= 500 MPa and > 250 MPa

[0381] Shock: designates the VW-40°C type shock, VW standard TL52435 2010

[0382] We note "++", a shock performance that we can qualify as "very good", which corresponds to <= 10% breakage.

[0383] We note "+", a shock performance that we can qualify as "good", which corresponds to <= 25% breakage and > 10% breakage

[0384] We note a shock performance that can be described as "quite bad", which corresponds to <= 75% breakage and > 25%

[0385] We note ", a shock performance that we can qualify as "very bad", which corresponds to > 75%

[0386] Aging: this refers to durability, in other words it refers to the resistance of the tube to oxidative aging in hot air. The tube is aged in air at 150°C, then it is shocked with a shock according to DIN 73378 standard, this shock being carried out at -40°C, the half-life (in hours) is indicated which corresponds to the time after which 50% of the tubes tested break. A qualitative comment accompanies this value.

[0387] We note "++", a durability that can be described as "very good", which corresponds to >= 200h of half-life.

[0388] We note "+", a durability (resistance to thermo-oxidative aging) that we can qualify as "good", which corresponds to >= 100h of half-life (and <200h)

[0389] We note a durability (resistance to thermo-oxidative aging) that can be described as "acceptable", which corresponds to >= 50h of half-life (and <100h)

[0390] We note a durability (resistance to thermo-oxidative aging) which can be described as "poor", which corresponds to <50h

[0391] In the case where a half-life figure is given to show nuances, this figure is rounded by 25h increments, to take into account significant figures, linked to the precision of the evaluation.

[0392] Adh.: this is the adhesion force. It is translated by the measurement of the peel force, expressed in N / cm, and measured on the tube of diameter 8mm and thickness 1mm having undergone conditioning of >=15 days at 50% relative humidity at 23°C, such that hygroscopic equilibrium is reached within the sample.

[0393] The value given concerns the weakest interface, i.e. the least adherent of the multilayer, where there is therefore the greatest risk of detachment. Peeling is carried out at the interface by subjecting one of the parts to traction at an angle of 90° and at a speed of 50mm / min according to the following process.

[0394] A 9mm wide strip of tube is cut. This strip is therefore tile-shaped and still has all the layers of the original tube. The separation of the two layers of the interface, which we wish to evaluate, is started using a knife. Each of the layers thus separated is placed in the jaws of a tensile machine. The peeling is carried out by pulling these 2 layers on either side at 180 degrees and at a speed of 50 mm / min. The strip, and therefore the interface, is maintained at 90 degrees relative to the direction of traction.

[0395] We note:

[0396] +++: very good, > 50

[0397] ++: good, >20 and <=50

[0398] +: fairly good (acceptable), >10 and <=20

[0399] - : bad, <=10

[0400] All.%: this is the elongation at break carried out according to the ISO R527 standard except that measured on a tube with a diameter of 8mm and a thickness of 1mm. The sample is ISO conditioned, this is a conditioning of >=15 days at 50% relative humidity at 23°C such that hygroscopic equilibrium is reached within the sample.

[0401] We note:

[0402] +++: very good, >=200% elongation

[0403] ++: good, >=100 and <200% elongation

[0404] +: unsatisfactory: <100% elongation

[0405] The results are shown in Table 1.

[0406] [Tables 1] Example Structure and thickness of layers (in % of total thickness) Ch oc Viei 11. Fie X. Ad h. AU. % Exl 11NX3 / / MLT-cxl 1-recy + 20% MLTcx3 1-recy / / OHhi / / 11NX3 15 / 30 / 15 / 40% + + NT ++ +++ Ex2 PA12ünodl / / MLTcx21-recy / / PA12üno dl 20 / 60 / 20% ++ + NT ++ +++ Ex3 PA12ünodl / / MLT-cx21-recy / / MXD6hi / / 11NX3 15 / / 30 / / 15 / / 40% + + NT ++ +++ against exempt es cxl PA12PL / / PA12HIPHL-recy / / PA12PL 15 / 70 / 15% - - + +++ +++ cx2 PA12PL / / PA12PL-recy / / PA12PL 15 / 70 / 15% — - + +++ +++ cx3 PA12PL / / PA1 IPL-recy / / PA12PL 15 / 70 / 15% - - + +++ +++ cx4 Monolayer PA12PL-recy — - + NT + cx5 monolayer PAllPL-recy + - ++ NT + cx6 Monolayer PAllPL-recy2 ++ - ++ NT ++ cx7 Monolayer PA12HIP-recy3 + - ++ NT ++ cx8 Monolayer 1012-recy - - + NT +

[0407] NT: Not tested

Claims

Claims

1. Multi-layer tubular structure (MLT) intended for the transport of automotive fluids, in particular air, oil, water, a urea solution, a glycol-based coolant, or a fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel, or hydrogen, comprising at least three layers: at least one layer (1) consisting of a composition comprising at least 50% of polyamide resins consisting of at least a first polyamide resin comprising predominantly aliphatic units and at least a second resin comprising predominantly aromatic units, said composition being constituted of at least 50% of recycled material originating from a multi-layer tube having initially transported automotive fluids, in particular as defined above,said tube being made up of a composition which predominantly comprises at least one polyamide, at least one layer (2) made up of a composition predominantly comprising at least one semi-crystalline aliphatic polyamide and optionally at least one impact modifier, and when the layer (2) is made up of a composition predominantly comprising at least one semi-crystalline aliphatic polyamide which is PA 12 and / or PA612 and / or PA 1010, then said composition comprises said impact modifier, and at least one layer (2') made up of a composition predominantly comprising at least one semi-crystalline aliphatic polyamide, said layer (2) and said layer (2') each being made up of at least 90% of non-recycled material.,

2. Multi-layer tubular structure (MLT) according to claim 1, wherein said layer (1) is located between a layer (2) and a layer (2').

3. Multi-layer tubular structure (MLT) according to one of claims 1 or 2, in which the layer (2') is the layer in contact with the fluid.

4. Multi-layer tubular structure (MLT) according to one of claims 1 to 3, in which the layer (2') is as defined for layer (2), and preferably layers (2) and (2') are identical.

5. Multi-layer tubular structure (MLT) according to one of claims 1 to 4, wherein at least one binder layer (3) is present, said layer (3) being located between layer (2) and layer (1) and / or between layer (1) and layer (2').

6. Multilayer tubular structure (MLT) according to one of claims 1 to 5, wherein said layer (1) represents at least 10%, in particular at least 30%, in particular at least 50% of the total thickness of said multilayer tubular structure (MLT).

7. Multilayer tubular structure (MLT) according to one of claims 1 to 6, in which said layer (1) is made up of a composition comprising: at least 50% by weight, in particular from 50% to 97% by weight, of at least one semi-crystalline aliphatic polyamide denoted C having an average number of carbon atoms per nitrogen atom denoted Cc of from 6 to 18, advantageously from 8 to 12; from 0 to 25% by weight of at least one semi-crystalline aliphatic polyamide denoted B and having an average number of carbon atoms per nitrogen atom denoted CB = Ce - 1, preferably CB = Ce - 2; from 0 to 25% by weight of a semi-crystalline aliphatic polyamide noted A having an average number of carbon atoms per nitrogen atom noted CA = CB - 1, preferably CA = CB - 2;from 0 to 45% by weight of at least one impact modifier, in particular from 3 to 45% by weight of at least one impact modifier, from 0 to 20% by weight of at least one plasticizer, from 0 to 2% by weight of at least one additive, the sum of the constituents being equal to 100%.;

8. A multi-layer tubular structure (MLT) according to one of claims 1 to 7, wherein the recycled material comes from a multi-layer tube selected from a crushed multi-layer tube, a crushed and recompounded multi-layer tube, and a crushed, recompounded and reformulated multi-layer tube.

9. Multilayer tubular structure (MLT) according to claim 8, wherein said composition of the layer (1) is free of plasticizer and / or impact modifier and said recycled material comes from a multilayer tube chosen from a crushed multilayer tube, a crushed and recompounded multi-layer tube, and crushed, recompounded and reformulated multi-layer tube.

10. Multi-layer tubular structure (MLT) according to claim 8, wherein said composition of the layer (1) comprises at least one compound chosen from plasticizer, an impact modifier and an additive, and said recycled material comes from a multi-layer tube chosen from a crushed, then recompounded and reformulated multi-layer tube.

11. A multi-layer tubular structure (MLT) according to one of claims 1 to 10, wherein the fluid transported by said multi-layer tube is the same as that of said multi-layer tubular structure (MLT).

12. Multi-layer tubular structure (MLT) according to one of claims 1 to 10, wherein the fluid transported by said multi-layer tube is different from that of said multi-layer tubular structure.

13. Multilayer tubular structure (MLT) according to one of claims 1 to 12, in which the layer (2) is made up of a composition comprising: at least 50% by weight, in particular from 50% to 97% by weight, in particular from 50% to 95% by weight, of at least one semi-crystalline aliphatic polyamide denoted D having an average number of carbon atoms per nitrogen atom denoted CD of from 6 to 18, advantageously from 9 to 15; from 0 to 50% by weight of at least one semi-crystalline aliphatic polyamide denoted E and having an average number of carbon atoms per nitrogen atom denoted CE = CD - 1, preferably CE = CD - 2; from 0 to 50% by weight of a semi-crystalline aliphatic polyamide noted F having an average number of carbon atoms per nitrogen atom noted CE = CE - 1, preferably CE = CE - 2;from 3 to 45% by weight of at least one impact modifier, in particular from 5 to 20% by weight of at least one impact modifier, from 0 to 20% by weight of at least one plasticizer, from 0 to 2% by weight of at least one additive, from 0 to 35% of at least one antistatic filler, the sum of the constituents being equal to 100%.;

14. Multilayer tubular structure (MLT) according to claim 13, wherein said composition of said layer (1) is free of polyamides denoted A and B and said composition of said layer (2) comprises polyamides chosen from those denoted E, F and a mixture thereof.

15. Multilayer tubular structure (MLT) according to claim 14, wherein said composition of said layer (1) comprises polyamides chosen from those denoted A, B and a mixture thereof, and said composition of said layer (2) is free of polyamides denoted E and F.

16. Multi-layer tubular structure (MLT) according to one of claims 13 to 15, in which the layer (1) comes from a recycled multi-layer tube

17. Multilayer tubular structure (MLT) according to one of claims 1 to 16, in which the Tf of the majority aliphatic semi-crystalline polyamide of the layer (1) is <225°C, in particular <200°C as determined by DSC according to standard ISO 11357-3:2013, at a heating rate of 20K / min.

18. Multilayer tubular structure (MLT) according to one of claims 1 to 17, in which the majority of the aliphatic semi-crystalline polyamide in the layer (1) has a crystallization enthalpy > 25 J / g, preferably > 40 J / g, in particular > 45 J / g as determined by DSC according to standard ISO 11357-3:2013, at a heating rate of 20K / min.

19. Multi-layer tubular structure (MLT) according to one of claims 1 to 18, in which the MLT consists of three layers of the following structure: (2) / / (1) / / (2).