WO2023118700A1

WO2023118700A1 - Recycled polyamide composition and single-layer tubular structure comprising same

Info

Publication number: WO2023118700A1
Application number: PCT/FR2022/052349
Authority: WO
Inventors: Marjorie MARCOURT; Thomas PRENVEILLE; Nicolas Dufaure; Sébastien VAUTIER; Thierry Vasselin; Florent Dechamps; Pierre NIDERCORN
Original assignee: Arkema France
Priority date: 2021-12-20
Filing date: 2022-12-14
Publication date: 2023-06-29
Also published as: FR3130813A1

Abstract

The present invention relates to a composition predominantly comprising at least one catalyzed semi-crystalline aliphatic polyamide, said composition consisting of at least 30% by weight, in particular at least 50% by weight of recycled material originating from at least one single-layer and/or multilayer tube having been intended for the transport of automotive fluids, in particular as defined above, said at least one single-layer and/or multilayer tube consisting of a composition which predominantly comprises at least one catalyzed or non-catalyzed polyamide, said at least one single-layer and/or multilayer tube having undergone milling and then at least one recompounding with or without addition of at least one catalyst in order to be able to be recycled, a simple single grinding being excluded, said polyamide of said tube having been intended for the transport of automotive fluids having functions derived from oxidation reactions selected from imide functions, carboxylic acids, primary amides, alcohols and mixtures thereof, in a molar ratio relative to the secondary amide functions, which is higher than that of the same polyamide, constituting a non-used tube that has still never been transported or contained in fluids for a motor vehicle.

Description

DESCRIPTION

TITLE OF THE INVENTION: COMPOSITION BASED ON RECYCLED POLYAMIDE AND SINGLE-LAYER TUBULAR STRUCTURE COMPRISING IT

The present invention relates to a composition based on recycled polyamide and a single-layer tubular structure comprising it.

Said single-layer tubular structure is used for transporting automotive fluids based on recycled polyamides originating from a single-layer and/or multilayer tube having been intended for the transport of said automotive fluids.

Every year, several million motor vehicles fall out of use around the world. An end-of-life motor vehicle (VHU) contains many toxic and polluting products (liquid or solid): motor oil, battery, air conditioning fluid, explosive elements of airbags, etc. Treated in poor conditions, this waste can lead to soil and water pollution, as well as accidents. ELVs are therefore considered hazardous waste.

A large number of vehicle components can be recovered and recycled, in the form of second-hand spare parts or raw materials. Parts intended for reuse (headlights, indicators, engine, radiator, starter, bonnet, fenders, doors, etc.) are dismantled and stored for resale.

Non-recyclable carcasses and parts (ferrous and non-ferrous metals, plastics, glass, rubber, etc.) are crushed to be recycled or landfilled.

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.

Only 5% of ultimate waste should therefore remain, i.e. waste which is not likely to be treated under the technical and economic conditions of the moment and which will be incinerated or evacuated to specific storage centers. .

The 95% reused and recovered are subject to:

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

Material recovery: Reuse or reuse: new use of a part that 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 virgin material.

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 biogasoline or diesel, in particular biodiesel, or hydrogen.

These pipes can be monolayer and/or multilayer tubular structures, in particular based on polyamide(s).

When the motor vehicle is out of service, certain pipes present in it may be too degraded to be able to be reused such as, in the form of a tube, without risk or without this leading to excessively degraded usage properties.

Indeed, the tubes, especially 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.

In addition, a pipe for transporting a fuel, 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 may be partly depolymerized and/or degraded and has lost most of its stabilizers, which prohibits its safe reuse.

Up to now, the end-of-life automobile hose 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.

In addition, 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.

The reuse, without modification, of tubes taken from end-of-life cars is therefore not envisaged for 4 reasons:

- Analysis of end-of-life tubes showed that they had stiffened compared to a new tube: the end-of-life tube has a higher threshold stress

(loss of additives, and crystallization induced by the working environment). This stiffening is a problem because the tube risks being damaged during disassembly and assembly on a new vehicle (tubes particularly stressed during feathering).

- end-of-life tubes may have undergone chemical degradation. Their aging resistance is therefore much lower than that of tubes made from virgin product.

- Tubes at the end of their life have also been thermoformed to fit exactly into the end-of-life vehicle model. Model which will probably no longer be produced 10 to 15 years after the sale of the vehicle at the end of its life.

- A layer of oligomer is present (on some) inside the tubes. A cleaning step is necessary to remove this layer of oligomer.

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

The present invention therefore relates to a composition mainly comprising at least one catalyzed semi-crystalline aliphatic polyamide, said composition consisting of at least 30% by weight, in particular of at least 50% of recycled material originating from at least one tube monolayer and/or multilayer having been intended for the transport of automotive fluids, in particular as defined above, said at least one monolayer and/or multilayer tube consisting of a composition which mainly comprises at least one catalyzed or non-catalyzed polyamide , said at least one monolayer and/or multilayer tube having undergone grinding then at least one recompounding with or without addition of at least one catalyst in order to be able to be recycled, simple single grinding being excluded, said polyamide of said tube having been intended for the transport of automobile fluids having functions resulting from oxidation reactions chosen from imide functions, carboxylic acids, primary amides, alcohols and mixtures thereof, in a molar ratio relative to the secondary amide functions greater than that of the same polyamide constituting a tube unused that has never previously transported or contained motor vehicle fluids.

The inventors have therefore surprisingly found that a composition based on catalyzed or non-catalyzed semi-crystalline polyamide and consisting of at least 30%, in particular of at least 50%, of recycled material allows the constitution of a tubular structure monolayer consisting of a layer (1) consisting of said composition, said structure being capable of transporting an automotive fluid in particular air, oil, water, a urea solution, a coolant based on glycol, or a fuel such as gasoline, in particular bio-gasoline or diesel, in particular bio-diesel, or hydrogen, and this regardless of the type of fluid initially transported by the recycled single-layer and/or multi-layer tube constituting the single layer, layer in contact with the transported fluid, said single-layer structure having, against all odds, much better properties than those of the same tubular structure whose layer (1) to semi-crystalline polyamide base catalyzed and consisting of at least 30, in particular at least 50% of recycled material is of simply ground origin.

Grinding followed by recompounding without addition of catalyst for a polyamide catalyzed and collected on VHU makes it possible to recover the original inherent viscosity and therefore at least the qualities of the original tube, whereas simple grinding does not make it possible to recover the original inherent viscosity.

Furthermore, grinding followed by recompounding without adding catalyst for an uncatalyzed polyamide collected on an ELV does not make it possible to recover the original inherent viscosity and therefore the qualities of the original tube.

Thus, in the where said at least one monolayer and/or multilayer tube consists of a composition which mainly comprises at least one uncatalyzed polyamide, the addition of a catalyst during the recompounding is essential so that said monolayer tube and/or multilayer can be recycled.

Said tube having been intended for the transport of automotive fluids therefore corresponds to a used tube.

Such recompounding is conventionally carried out by introducing the ground material at least once into an extruder, in particular of the co-rotating twin-screw type, or of the co-kneader type (Buss), where the ground material is remixed by melting, with or without addition of at least a compound chosen from a semi-crystalline aliphatic polyamide, of recycled origin or not, with or without the addition of a catalyst. The molten material emerges from the extruder in rods which are cooled and cut into granules which will then then be introduced into an extruder for the manufacture of the monolayer or multilayer tubular structure.

The polyamides, whether they are derived from the polycondensation of a lactam, an amino acid or a diamine with a dicarboxylic acid (or a mixture of these) consist mainly of secondary amide functions (R-CO -NH-R').

During the use in motor vehicles of tubes for the transport or storage of fluids, new species resulting from oxidation mechanisms, in particular secondary amide functions and/or methylene alpha to said secondary amide functions appear, such as that imide, nitrile, methyl groups at the end of the chain, alkenes, formamides, carboxylic acids, primary amides and alcohols appear in the polyamides constituting said tubes or reservoirs. The primary amide functions correspond to an R”-CONH ₂ type structure.

Said functions can be detected by infrared spectrometry. Thus the absorption band from 1700 to 1740cm-1 corresponds to an imide, that from 1680 to 1720 cm-1 to the carbonyl of the carboxylic acid and that from 3580 to 3670 cm-1 corresponds to the alcohol function of the acid carboxylic.

The absorption band from 3580 to 3670 cm-1 corresponds to the free alcohol function.

The amide function is characterized on the one hand by a couple of absorption bands from 3100 to 3500 cm-1 and from 15560 to 1640 cm-1 which corresponds to the NH group of the amide and on the other hand by the band d absorption of 1650 to 1700 cm-1 which corresponds to the carbonyl group of the amide.

On the other hand, the fluid residues present in said tube are totally or partially extracted, before or after grinding of said tube and/or reservoir.

In a first embodiment, said molar ratio of the functions resulting from oxidation reactions relative to the secondary amide functions is comprised from 1/10000 to 1/20. The concentrations can be measured by proton NMR in dichloromethane-d2, by adding HFIP (hexafluoroisopropanol) to solubilize the polyamide.

For example, 20 mg of polymer can be dissolved in 0.7 mL of solvent with an HFIP/CD2Cl2 ratio of 1/3.

Some of the functions mentioned below can be observed for example in 13C NMR. Thus the line at 36 ppm corresponds to the CH2 at the a of the primary amide, that at 34 ppm corresponds to the CH2 at the a of the carboxylic acid. These species can be quantified by integrating the area under the lines and comparing them to the area under the 37.1 ppm line corresponding to the secondary amide.

Similarly, the lines corresponding to the carbonyl groups of the primary amide, carboxylic acid and secondary amide functions are observed at 181.2 ppm, 179.6 ppm and 177.4 ppm respectively.

The line at 16.7 ppm corresponds to the CH2 in a of the nitrile group.

The formamide moiety gives a chemical shift at 163.0 ppm and 166.3 ppm.

Other functions mentioned above can be observed in proton NMR (1 H NMR) the solvent HFIP/CD2Cl2 as described above. The line of the CHO groups of the formamides emerges at 7.92 and 8.01 ppm. The line corresponding to the CH2 in a of the primary amides can be observed at 2.30 ppm. The 0.9 ppm line corresponds to the CH3 groups of the CH3-(CH2)n type. The line at 2.40 ppm corresponds to the CH2 in a of the nitrile function. In a similar way to what is described for carbon NMR, the ratios of new functions with respect to secondary amides can be determined by integrating the area under the lines and comparing them to the area under the line corresponding to the CH2 in a secondary amide (2.20 ppm). In a first variant, said molar ratio of the imide functions relative to the secondary amide functions is comprised from 1/1000 to 1/20, in particular from 1/500 to 1/20, in particular from 1/200 to 1/50.

In one embodiment of this first variant, said molar ratio of the imide functions relative to the secondary amide functions is comprised from 1/1000 to 1/100, in particular from 1/1000 to 1/300, in particular from 1/1000 to 1/500, more particularly from 1/1000 to 1/750.

In another embodiment of this first variant, said molar ratio of the imide functions relative to the secondary amide functions is comprised from 1/750 to 1/20, in particular from 1/750 to 1/50, in particular from 1/750 to 1/100, more particularly from 1/750 to 1/300, especially from 1/750 to 1/500.

In yet another embodiment of this first variant, said molar ratio of the imide functions relative to the secondary amide functions is comprised from 1/500 to 1/20, in particular from 1/500 to 1/100, in particular from 1/ 750 at 1/300.

In yet another embodiment of this first variant, said molar ratio of the imide functions relative to the secondary amide functions is comprised from 1/300 to 1/20, in particular from 1/300 to 1/50, in particular from 1/ 300 to 1/100.

In a second variant, said molar ratio of the carboxylic acid functions relative to the secondary amide functions is comprised from 1/5000 to 1/20, in particular from 1/3000 to 1/25, in particular from 1/3000 to 1/50, very advantageously comprised from 1/500 to 1/25.

In one embodiment of this second variant, said molar ratio of the carboxylic acid functions relative to the secondary amide functions is comprised from 1/1000 to 1/100, in particular from 1/500 to 1/100, in particular from 1/400 to 1/100, more particularly from 1/300 to 1/100.

In a third variant, said molar ratio of the alcohol functions relative to the secondary amide functions is comprised from 1/1000 to 1/20 and advantageously comprised from 1/1000 to 1/25 very advantageously comprised from 1/200 to 1/50.

In one embodiment of this third variant, said molar ratio of the alcohol functions relative to the secondary amide functions is comprised from 1/1000 to 1/200, in particular from 1/1000 to 1/300, in particular from 1/1000 to 1/400, more particularly from 1/1000 to 1/500.

In a fourth variant, said molar ratio of the primary amide functions relative to the secondary amide functions is between 1/500 and 1/15, in particular from 1/400 to 1/15, in particular from 1/300 to 1/15, more particularly from 1/200 to 1/15, in particular from 1/100 to 1/15.

In a fifth variant, said molar ratio of the methyl functions at the end of the chain relative to the secondary amide functions is comprised from 1/1000 to 1/50, in particular from 1/500 to 1/50, in particular from 1/400 to 1 /50, more particularly from 1/300 to 1/50, in particular from 1/200 to 1/100.

In a sixth variant, said molar ratio of the nitrile functions relative to the secondary amide functions is comprised from 1/300 to 1/10 and advantageously comprised from 1/200 to 1/10 very advantageously comprised from 1/100 to 1/10. , even more advantageously 1/50 to 1/10.

The composition also advantageously comprises residues of stabilizers chosen from phenols, quinones, stylbenequinone and phosphite.

The recycled polyamide advantageously comprises alkyl chain ends with a carbon number (between 1 and 18) higher than that of a virgin PA. Advantageously, the content of chain ends is between 1 ppm and 0.5%.

In one embodiment, said composition consists of at least 50% recycled material originating from at least one single-layer and/or multi-layer tube having been intended for the transport of automotive fluids.

In one embodiment, said at least one monolayer and/or multilayer tube consists of a composition which mainly comprises at least one catalyzed polyamide, said at least one monolayer and/or multilayer tube having undergone grinding then at least one recompounding without adding a catalyst to be able to be recycled.

In another embodiment, said at least one monolayer and/or multilayer tube consists of a composition which mainly comprises at least one catalyzed polyamide, said at least one monolayer and/or multilayer tube having undergone grinding then at least one recompounding with the addition of a catalyst so that it can be recycled.

In one embodiment, said composition of the layer (1) is devoid of plasticizer and/or impact modifier.

In one embodiment, said composition of the layer (1) comprises at least one compound chosen from plasticizer, an impact modifier and an additive.

In another embodiment, the Tm of the predominant aliphatic semi-crystalline polyamide of said composition of layer (1) is <225°C, in particular ^200°C as determined by DSC according to standard ISO 1 1357-3 :2013, at a heating rate of 20K/min. In another embodiment, the predominant aliphatic semi-crystalline polyamide of said composition of layer (1) has an enthalpy of crystallization > 25 J/g, preferentially > 40 J/g, in particular > 45 J/g such that determined by DSC according to ISO 1 1357-3:2013, at a heating rate of 20K/min.

According to another aspect, the present invention relates to a single-layer tubular structure intended for the transport of automotive fluids, in particular air, oil, water, a urea solution, a coolant based on of glycol, or a fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel, or hydrogen, consisting of a layer (1 ) consisting of a composition as defined above.

In one embodiment, said tubular structure having present during the first storage of gasoline, in particular alcoholic gasoline, at most 0.3 g/m2 of insoluble extract, advantageously at most 0.2 g/m ² .

In one embodiment, said said tubular structure has, during the first storage of gasoline, in particular alcoholic gasoline, 30%, in particular 40%, in particular 50% less insoluble extract than the same tubular structure derived from not recycled

The monolayer tubular structure intended for the transport of fluids for a motor vehicle of the invention makes it possible to greatly reduce the proportion of extractables as determined by a test which consists in filling a tubular structure with alcoholic gasoline type FAM-B and heating the whole at 60° C. for 96 hours, then emptying it by filtering the fluid into a beaker.

The insoluble extracts present during filtration on the filter are weighed after drying and represent less than 0.3 g/m2.

The soluble extracts are quantified by allowing the filtrate in the beaker to evaporate at room temperature and then by weighing this residue. The proportion of soluble extracts is advantageously less than or equal to approximately 15g/m2 of internal tube surface.

Said tubular structure has a rate of extractables lower than that of the same tubular structure resulting from non-recycled material, that is to say virgin or original during the first storage of gasoline, in particular alcoholic gasoline and in particular a proportion of insoluble extract lower by 30%, in particular by 40%, in particular by 50% compared to the proportion present in the same tubular structure but resulting from non-recycled or virgin material.

All the characteristics described for the composition of the layer (1) above are valid for the structure. In another embodiment, said at least one monolayer and/or multilayer tube consists of a composition which mainly comprises at least one catalyzed polyamide, said at least one monolayer and/or multilayer tube having undergone grinding then at least one recompounding without adding a catalyst to be able to be recycled. In yet another embodiment, said at least one monolayer and/or multilayer tube consists of a composition which mainly comprises at least one catalyzed polyamide, said at least one monolayer and/or multilayer tube having undergone grinding then at least recompounding with the addition of a catalyst so that it can be recycled.

A polyamide-based layer means that there is at least 50% by weight of polyamides in the layer (1).

The term "fluid" means a gas or liquid used in automobiles, in particular air, oil, water, urea solution, glycol-based coolant, or a fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel, or hydrogen.

Advantageously, said fluid denotes fuels, in particular gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular biodiesel.

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, alcohols being able to be the majority components in certain cases.

The expression “alcoholic gasoline” designates a gasoline in which methanol or ethanol has been added. It also designates an E95 type gasoline which does not contain any petroleum distillation product.

The expression “based on polyamide” means at least 50% by weight of polyamide in the layer.

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

As already specified above, when the motor vehicle is out of use, the various pipes present in it can be too degraded to be able to be reused such as, in the form of a tube, without risk or without this leading to excessively degraded usage properties.

The tube to be reused or in other words to be recycled (single-layer and/or multi-layer) is therefore removed from the automobile and first undergoes grinding, then this ground tube is recompounded, that is to say that the ground material is again entered at least once an extruder, in particular of the co-rotating twin-screw type, or of the co-kneader type (Buss), where the ground material is remixed by melting, with or without addition of at least one catalyst. The molten material emerges from the extruder in rods which are cooled and cut into granules.

If the composition of the layer (1) consists of less than 100% recycled material, it is then necessary to add a polyamide (identical or different) of non-recycled origin to the material to be recycled and this can be done when passing through the extruder at least once or else by prior compounding of the granules obtained above with said polyamide of non-recycled origin.

Regarding the layer (1)

The layer (1) consists of a composition mainly comprising at least one catalyzed semi-crystalline aliphatic polyamide, said composition consisting of at least 30% by weight, in particular at least 50% of recycled material from a tube monolayer and/or multilayer having been intended for the transport of automotive fluids, said tube consisting of a composition which mainly comprises at least one catalyzed or non-catalyzed polyamide, said tube having undergone grinding then at least one recompounding with or without addition of at least one catalyst to be able to be recycled. The addition of the catalyst depends on whether or not the catalyst was originally present in the single-layer and/or multi-layer tube which was intended for the transport of automotive fluids and is therefore used.

In a first variant, said layer (1) consists of a composition comprising: at least 30% of a catalyzed polyamide originating from a single-layer and/or multi-layer tube consisting of a composition which mainly comprises at least one polyamide not catalyzed and which has been recompounded at least once after grinding with the addition of a catalyst in a proportion of 0.005% to 0.5% by weight of a catalyst relative to the total weight of said polyamide plus added catalyst originating from said tube, the balance 100% being a catalyzed or uncatalyzed semi-crystalline polyamide, in particular catalyzed, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition.

In a first embodiment of the first variant, said layer (1) consists of a composition comprising: at least 40% of said catalyzed polyamide originating from said recompounded tube with the addition of catalyst, the remainder at 100% being a semi-polyamide catalyzed crystalline, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition.

In a second embodiment of the first variant, said layer (1) consists of a composition comprising: at least 50% of said catalyzed polyamide originating from said tube recompounded with the addition of catalyst, the remainder at 100% being a semi-polyamide catalyzed crystal, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition.

In a third embodiment of the first variant, said layer (1) consists of a composition comprising: at least 60% of said catalyzed polyamide originating from said tube recompounded with the addition of catalyst, the remainder at 100% being a semi-polyamide catalyzed crystal, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition.

In a fourth embodiment of the first variant, said layer (1) consists of a composition comprising: at least 70% of said catalyzed polyamide originating from said tube recompounded with the addition of catalyst, the remainder at 100% being a semi-polyamide catalyzed crystal, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition.

In a fifth embodiment of the first variant, said layer (1) consists of a composition comprising: at least 80% of said catalyzed polyamide originating from said recompounded tube with the addition of catalyst, the remainder at 100% being a semi-polyamide catalyzed crystal, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition.

In a sixth embodiment of the first variant, said layer (1) consists of a composition comprising: at least 90% of said catalyzed polyamide originating from said recompounded tube with the addition of catalyst, the remainder at 100% being a semi- catalyzed crystalline, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition.

In a seventh embodiment of the first variant, said layer (1) consists of a composition comprising:

100% of said catalyzed polyamide coming from said recompounded tube with the addition of catalyst, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition.

Advantageously, said composition of the layer (1) in this first variant may comprise other constituents such as impact modifiers, plasticizers, additives with the exception of catalysts. Said constituents then substitute the balance for 100% catalyzed semi-crystalline polyamide.

Advantageously, said composition of the layer (1) in this first variant is devoid of plasticizer and/or impact modifier.

Advantageously, said layer (1) consists of a composition consisting of the constituents as defined for each embodiment of the first variant.

Advantageously, in this first variant, the number of recompounding is comprised from 1 to 10, in particular from 1 to 5, in particular the number of recompounding is 1, 2, 3, 4 or 5, in particular 1, 2 or 3.

In one embodiment of this first variant, the recompounding is carried out without adding plasticizer, impact modifier and additives such as 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.

In another embodiment, the recompounding is carried out with only an addition of catalyst.

In a second variant, said layer (1) consists of a composition comprising: at least 30% of a catalyzed polyamide originating from a monolayer and/or multilayer tube consisting of a composition which mainly comprises at least one catalyzed polyamide and which has been recompounded at least once after grinding without adding a catalyst, the proportion by weight of catalyst being between 0.005% and 0.5% relative to the total weight of said polyamide and catalyst, the balance to 100% being a catalyzed or uncatalyzed semi-crystalline polyamide, in particular catalyzed, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition.

In a first embodiment of the second variant, said layer (1) consists of a composition comprising: at least 40% of said catalyzed polyamide originating from said recompounded tube, the remainder to 100% being a catalyzed semi-crystalline polyamide, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition.

In a second embodiment of the second variant, said layer (1) consists of a composition comprising: at least 50% of said catalyzed polyamide originating from said recompounded tube, the remainder to 100% being a catalyzed semi-crystalline polyamide, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition.

In a third embodiment of the second variant, said layer (1) consists of a composition comprising: at least 60% of said catalyzed polyamide originating from said recompounded tube, the remainder at 100% being a catalyzed semi-crystalline polyamide, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition.

In a fourth embodiment of the second variant, said layer (1) consists of a composition comprising: at least 70% of said catalyzed polyamide originating from said recompounded tube, the remainder to 100% being a catalyzed semi-crystalline polyamide, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition.

In a fifth embodiment of the second variant, said layer (1) consists of a composition comprising: at least 80% of said catalyzed polyamide originating from said recompounded tube, the remainder to 100% being a catalyzed semi-crystalline polyamide, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition. In a sixth embodiment of the second variant, said layer (1) consists of a composition comprising: at least 90% of said catalyzed polyamide originating from said recompounded tube, the remainder to 100% being a catalyzed semi-crystalline polyamide, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition.

In a seventh embodiment of the second variant, said layer (1) consists of a composition comprising:

100% of said catalyzed polyamide coming from said recompounded tube, the proportion of catalyst in the composition being from 0.005% to 0.5% by weight relative to the total weight of the composition.

Advantageously, the initial inherent viscosity of the polyamide of said tube of one of the embodiments of one or the other of the two variants above, before use as determined according to ISO 307:2007 in m-cresol at 20 °C ranges from 1.3 dl/g to 1.6 dl/g.

Said tube is therefore free of any use.

Advantageously, the inherent viscosity of the polyamide of said used tube of one of the embodiments of one of the two variants above, before recycling as determined according to ISO 307:2007 in m-cresol at 20° C. is comprised from 0.8 dl/g to 1.6 dl/g.

Advantageously, the inherent viscosity of the composition of layer (1) after recycling of said tube, that is to say after grinding and recompounding with or without catalyst, as determined according to ISO 307:2007 in m-cresol at 20 °C ranges from 1.3 dl/g to 1.6 dl/g.

Advantageously, a degassing is carried out during at least one compounding, even more advantageously the degassing is located just after the melting zone in an extruder.

In one embodiment, the outgassing is low, meaning the outgassing is -50mmHg to -150mmHg.

In another embodiment, the outgassing is strong, which means the outgassing is from -550 mmHg to -750 mmHg.

Advantageously, the inherent viscosity of the composition of layer (1) after recycling with degassing of said tube, that is to say after grinding and recompounding with or without catalyst, and degassing, as determined according to ISO 307:2007 in the m-cresol at 20° C. ranges from 1.3 dl/g to 1.6 dl/g. Advantageously, said composition of the layer (1) in this second variant may comprise other constituents such as impact modifiers, plasticizers, additives with the exception of catalysts.

Said constituents then substitute the complement to 100% semi-crystalline polyamide, catalyzed or not, in particular catalyzed.

Advantageously, said composition of layer (1) in this second variant is devoid of plasticizer and/or impact modifier.

Advantageously, said layer (1) consists of a composition consisting of the constituents as defined for each embodiment of the second variant.

Advantageously, in this second variant, the number of recompounding is comprised from 1 to 10, in particular from 1 to 5, in particular 1, 2, 3, 4 or 5.

Whether in the first or second variant, the recycled polyamide can be identical to or different from the semi-crystalline aliphatic polyamide.

This means that the recycled polyamide can be aliphatic or semi-aromatic for example.

Advantageously, the recycled polyamide is aliphatic, more advantageously it is semi-crystalline aliphatic and even more advantageously, it has the same number of carbon atoms per nitrogen atom as the semi-crystalline aliphatic polyamide with which it is mixed when said polyamide recycled is not 100% present.

In one embodiment, the predominant aliphatic semi-crystalline polyamide of layer (1) has an enthalpy of crystallization > 25 J/g, preferentially > 40 J/g, in particular > 45 J/g as determined by DSC according to ISO 1 1357-3:2013 standard, at a heating rate of 20K/min.

The nomenclature used to define polyamides is described in standard ISO 1874-1:201 1 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation" and is well known to those skilled in the art.

The term “polyamide” according to the invention denotes both a homopolyamide and a copolyamide.

The expression "semi-crystalline aliphatic polyamide" within the meaning of the invention throughout the description designates aliphatic polyamides which have a melting temperature (Tm) and an enthalpy of fusion AH > 25 J/g, in particular > 40 J/g, in particular > 45J/g, as well as a glass transition temperature (Tg) as determined by DSC according to standard ISO 1 1357-1:2016 and ISO 11357-2 and 3:2013, at a speed heating rate of 20K/min. 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.

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

Throughout the description, the expressions Cn to Cm used for lactams, amino acids, diamine Xa and dicarboxylic acid Yb correspond to the average number of carbon atoms per nitrogen atom.

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.

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.

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 C10 to C18, more preferably C10 at C12.

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.

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.

Advantageously, said semi-crystalline aliphatic 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.

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

The diamine can be linear or branched. Advantageously, it is linear.

Said at least one C4-C36 diamine Xa can be chosen in particular from 1,4-butanediamine, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylediamine, 1,8-octamethylediamine, 1,9-nonamethyldiamine, 1,10-decamethyldiamine, 1,11-undecamethyldiamine, 1,12-dodecamethyldiamine, 1,13-tridecamethyldiamine, 1,14-tetradecamethyldiamine, 1,16-hexadecamethyldiamine and 1,18-octadecamethylediamine, octadecenediamine, eicosanediamine, docosanediamine and diamines obtained from fatty acids. Advantageously, said at least one diamine Xa is C5-C18 and chosen from 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylediamine, 1,8-octamethylediamine, 1,9-nonamethylediamine, 1,10-decamethyldiamine, 1,11-undecamethyldiamine, 1,12-dodecamethyldiamine, 1,13-tridecamethyldiamine, 1,14-tetradecamethyldiamine, 1,16-hexadecamethyldiamine and 1,18-octadecamethyldiamine.

Advantageously, said at least one C5 to C12 diamine Xa is chosen in particular 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. Advantageously, said at least one C6 to C12 diamine Xa is chosen in particular from 1,6-hexamethylenediamine, 1,7-heptamethylediamine, 1,8-octamethylediamine, 1,9-nonamethylediamine, 1,10- decamethylediamine, 1,11 - undecamethylediamine, 1,12-dodecamethylediamine.

Advantageously, the diamine Xa used is C10 to C12, in particular chosen from 1,10-decamethylediamine, 1,11-undecamethylediamine, 1,12-dodecamethylediamine.

Said at least one C4 to C36 dicarboxylic acid Yb can 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. The diacid can be linear or branched. Advantageously, it is linear.

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.

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.

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

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.

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

The expression "mainly comprising at least one catalyzed semi-crystalline aliphatic polyamide" means that said composition of the layer (1) comprises at least 50% by weight of at least one catalyzed semi-crystalline aliphatic polyamide relative to the total weight of said composition. The catalyst can come either from a non-recycled semi-crystalline aliphatic polyamide which has been added, or from a recycled single-layer and/or multi-layer tube already catalyzed and reground and recompounded without adding catalyst, or from a single-layer tube and/or uncatalyzed recycled multilayer regrinded and recompounded with the addition of catalyst.

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 at least one aliphatic polyamide semi-crystalline relative to the total weight of said composition.

The recycled material may come from a single-layer and/or multi-layer tube, said single-layer and/or multi-layer tubes having been intended for the transport of fluid for automobiles. Said tube is therefore a used tube, that is to say that it has been used for at least a year for the transport of said fluid defined above or that it has been used for less than a year but that the car containing it was scrapped. Said monolayer tube consists of a composition comprising an aliphatic polyamide semi-crystalline and optionally impact modifiers and/or additives and/or plasticizers and/or antistatic fillers.

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. It can therefore comprise other layers consisting of a thermoplastic polymer other than a semi-crystalline aliphatic polyamide, such as for example a polypropylene, a semi-aromatic polyamide or a poly ethylene vinyl alcohol (EVOH).

It is obvious that the single-layer tube can also be a mixture of single-layer tubes, that is to say for example two types of single-layer tubes each consisting of a different semi-crystalline aliphatic polyamide, for example a PA1 1 and a PA12.

It is also quite 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 polyamide, in particular of a polyamide semi-crystalline aliphatic.

Said single-layer and/or multi-layer tube which was intended for the transport of automotive fluid and which is therefore used undergoes various treatments in order to be able to be recycled: it is crushed and recompounded, that is to say that after crushing, the particles crushed are fed into an extruder,

A simply ground tube is therefore excluded from said used single-layer and/or multi-layer tube which has been intended for the transport of automotive fluid.

Advantageously, the Tm 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 .

In one embodiment, the fluid transported by said monolayer and/or multilayer tube is different from that of said monolayer tubular structure.

This means that if the single-layer and/or multi-layer tube has transported a fluid such as air, said single-layer tubular structure may be intended to transport gasoline or even if the single-layer and/or multi-layer tube has transported a fluid such as alcoholic gasoline, said single-layer tubular structure may be intended to transport diesel.

In another embodiment, the fluid transported by said monolayer and/or multilayer tube is the same as that of said monolayer tubular structure. This means that if the single-layer and/or multi-layer tube has transported a fluid such as gasoline, said single-layer tubular structure may be intended to transport gasoline, provided that the gasoline of the single-layer and/or multi-layer tube and of said monolayer tubular structure is the same as, for example, alcoholic gasoline. Advantageously, the recycled material comes from a monolayer tube.

Advantageously, the recycled material comes from a multilayer tube.

Advantageously, the recycled material comes from a single-layer tube consisting of a composition comprising only a polyamide 11 (PA11) or a polyamide 12 (PA12), in particular a polyamide 11 (PA11).

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 less than 95% recycled material.

In another embodiment, said composition of the layer (1) consists of 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% recycled material.

Recycled used single-layer or multi-layer pipe

In a first variant, said tube which was intended for transporting automotive fluid is single-layer, non-catalyzed, which is then ground and recompounded with the addition of catalyst.

In one embodiment of this first variant, the polyamide of said tube is an aliphatic or aromatic polyamide, in particular an aliphatic polyamide, in particular a semi-crystalline aliphatic polyamide.

Advantageously, in this first variant, the polyamide of said tube consists of a composition mainly comprising a semi-crystalline aliphatic polyamide chosen from PA6, PA610, PA612, PA1012, PA1010, PA11 and PA12, in particular the PA11.

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.

Advantageously, in this first variant, the semi-crystalline aliphatic polyamide is chosen from PA6, PA610, PA612, PA1012, PA1010, PA11 and PA12, in particular PA11 and said tube was intended for transport fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

In a second variant, said tube which was intended for the transport of automotive fluid is catalyzed monolayer which is then ground, recompounded without adding catalyst.

In one embodiment of this second variant, the polyamide of said tube is an aliphatic or aromatic polyamide, in particular an aliphatic polyamide, in particular a semi-crystalline aliphatic polyamide.

Advantageously, in this second variant, the polyamide of said tube consists of a composition mainly comprising a semi-crystalline aliphatic polyamide chosen from PA6, PA610, PA612, PA1012, PA1010, PA11 and PA12, in particular the PA11.

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.

Advantageously, in this second variant, the semi-crystalline aliphatic polyamide is chosen from PA6, PA610, PA612, PA1012, PA1010, PA11 and PA12, in particular PA11 and said tube was intended for transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

In a third variant, said tube which was intended for transporting automotive fluid is non-catalyzed multilayer which is then ground, recompounded with the addition of catalyst.

In one embodiment of this third variant, the polyamide of the majority layer of said tube is an aliphatic or aromatic polyamide, in particular an aliphatic polyamide, in particular a semi-crystalline aliphatic polyamide.

Advantageously in this third variant, the polyamide of said tube consists of a composition mainly comprising a semi-crystalline aliphatic polyamide chosen from PA6, PA610, PA612, PA1012, PA1010, PA11 and PA12, in particular PA11 .

Advantageously in this third 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.

Advantageously, in this third variant, the semi-crystalline aliphatic polyamide is chosen from PA6, PA610, PA612, PA1012, PA1010, PA11 and PA12, in particular the PA11 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.

In a fourth variant, said tube which was intended for transporting automotive fluid is catalyzed multilayer which is then ground, recompounded without adding catalyst.

In one embodiment of this fourth variant, the polyamide of the major layer of said tube is an aliphatic or aromatic polyamide, in particular an aliphatic polyamide, in particular a semi-crystalline aliphatic polyamide.

Advantageously, in this fourth variant, the polyamide of the majority layer of said tube consists of a composition mainly comprising a semi-crystalline aliphatic polyamide chosen from PA6, PA610, PA612, PA1012, PA1010, PA11 and PA12, in particular PA11.

Advantageously in this fourth 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.

Advantageously, in this fourth variant, the semi-crystalline aliphatic polyamide is chosen from PA6, PA610, PA612, PA1012, PA1010, PA11 and PA12, in particular PA11 and said tube was intended for transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

In a fifth variant, said tube which has been intended for the transport of automotive fluid is a mixture of non-catalyzed single-layer and non-catalyzed multi-layer tube, said mixture then being ground, recompounded with the addition of catalyst.

It would not be departing from the scope of the invention if one of the monolayer and multilayer tubes were catalyzed.

In one embodiment of this fifth variant, the polyamide of said monolayer tube and that of the major layer of said multilayer tube are an aliphatic or aromatic polyamide, in particular an aliphatic polyamide, in particular a semi-crystalline aliphatic polyamide.

Advantageously, in this fifth variant, the polyamide of said monolayer tube and that of the majority layer of said multilayer tube consist of a composition mainly comprising a semi-crystalline aliphatic polyamide chosen from PA6, PA610, PA612, PA1012, PA1010, PA11 and PA12, in particular PA1 1 . Advantageously in this fifth variant, said tube was intended for transporting fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

Advantageously, in this fifth variant, the semi-crystalline aliphatic polyamide is chosen from PA6, PA610, PA612, PA1012, PA1010, PA11 and PA12, in particular PA11 and said tube was intended for transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

In a sixth variant, said tube which has been intended for the transport of automotive fluid is a mixture of catalyzed single-layer and catalyzed multi-layer tube, said mixture then being ground, recompounded without adding catalyst. It would not be departing from the scope of the invention if one of the monolayer and multilayer tubes were uncatalyzed. In one embodiment of this sixth variant, the polyamide of said monolayer tube and that of the major layer of said multilayer tube are an aliphatic or aromatic polyamide, in particular an aliphatic polyamide, in particular a semi-crystalline aliphatic polyamide.

Advantageously, in this sixth variant, the polyamide of said monolayer tube and that of the majority layer of said multilayer tube consist of a composition mainly comprising a semi-crystalline aliphatic polyamide chosen from PA6, PA610, PA612, PA1012, PA1010, PA11 and PA12, in particular PA1 1 . 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.

Advantageously, in this sixth variant, the semi-crystalline aliphatic polyamide is chosen from PA6, PA610, PA612, PA1012, PA1010, PA11 and PA12, in particular PA11 and said tube was intended for transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

In a seventh variant, said tube which has been intended for the transport of automotive fluid is a mixture of monolayer and multilayer tube, said mixture consisting of more than 50% of uncatalyzed tube and less than 50% of catalyzed tube, said mixture then being ground, recompounded without adding catalyst.

In one embodiment of this seventh variant, the polyamide of said monolayer tube and that of the majority layer of said multilayer tube are a polyamide aliphatic or aromatic, in particular an aliphatic polyamide, in particular a semi-crystalline aliphatic polyamide.

Advantageously, in this seventh variant, the polyamide of said monolayer tube and that of the majority layer of said multilayer tube consist of a composition mainly comprising a semi-crystalline aliphatic polyamide chosen from PA6, PA610, PA612, PA1012, PA1010, PA11 and PA12, in particular PA1 1 . 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.

Advantageously, in this seventh variant, the semi-crystalline aliphatic polyamide is chosen from PA6, PA610, PA612, PA1012, PA1010, PA11 and PA12, in particular PA11 and said tube was intended for transport of fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel.

In an embodiment of one of the seven variants above, the initial inherent viscosity of the polyamide of said tube before use as determined according to ISO 307:2007 in m-cresol at 20° C. is between 1.3 dl /g to 1.6 dl/g.

The polyamide of said tube is therefore free of any use.

In an embodiment of one of the seven variants above, the inherent viscosity of the polyamide of said used tube, before recycling as determined according to ISO 307:2007 in m-cresol at 20° C. is between 0.8 dl/g to 1.6 dl/g.

In an embodiment of one of the seven variants above, the initial inherent viscosity of the polyamide of said tube after recycling, that is to say after grinding and recompounding with or without catalyst, as determined according to ISO 307: 2007 in m-cresol at 20° C. is between 1.3 dl/g and 1.6 d/g.

Advantageously, the composition is degassed during the compounding, even more advantageously the degassing is located just after the melting zone of an extruder. Advantageously, a degassing is carried out during at least one compounding, even more advantageously the degassing is located just after the melting zone in an extruder.

In another embodiment, the outgassing is strong, which means the outgassing is from -550 mmHg to -750 mmHg. In an embodiment of one of the seven variants above, the inherent viscosity of the polyamide of said tube after recycling with degassing, that is to say after grinding and recompounding with or without catalyst, and degassing, as determined according to ISO 307:2007 in m-cresol at 20° C. is between 1.3 dl/g and 1.6 dl/g.

Advantageously, said tube which was intended for the transport of fluid for automobiles is single-layered.

Regarding the catalyst

The term “catalyst” designates a polycondensation catalyst such as an inorganic or organic acid.

Advantageously, the proportion by weight of catalyst is between about 50 ppm to about 5000 ppm, in particular from about 100 to about 3000 ppm relative to the total weight of the composition.

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

Regarding the process

According to another aspect, the present invention relates to a process for manufacturing a single-layer tubular structure as defined above, comprising a step of grinding and at least one step of recompounding at least one single-layer and/or multi-layer tube having been intended for the transport of automotive fluids.

The tube to be reused or in other words to be recycled (single-layer and/or multi-layer), whether catalyzed or not, is therefore removed from the automobile and first undergoes grinding, then this ground tube is recompounded, that is to say that the ground material is again introduced at least once 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, with or without addition of at least one catalyst. If the material to be recycled must be mixed with unused virgin material, then the latter is either ground beforehand if it comes from a tube and mixed with the ground material to be recycled to be recompounded together or the ground material from the tube to be reused (or in other words to be recycled) and granules (or shredded material) of unused virgin material are first mixed to be recompounded together.

Optionally, the tube to be reused, whether catalyzed or not and removed from the automobile, undergoes a washing and/or cleaning step before shredding.

Optionally, the crushed tube undergoes a washing and/or cleaning step after crushing. Optionally, the tube to be reused, whether catalyzed or not and removed from the automobile, undergoes a washing and/or cleaning step before shredding, then is shredded and then undergoes optionally, before the recompounding, a step of washing and/or cleaning after grinding.

The cleaning step can be carried out for example under vacuum.

The molten material emerges from the extruder in rods which are cooled and cut into granules.

In one embodiment, at least one recompounding step is carried out with the addition of a catalyst.

Advantageously, said at least one monolayer and/or multilayer tube is uncatalyzed.

In another embodiment, at least one recompounding step is carried out with the addition of a catalyst and said at least one monolayer and/or multilayer tube is uncatalyzed.

Advantageously, said at least one tube is monolayer.

Advantageously, said at least one tube is multilayer.

Advantageously, said at least one monolayer and/or multilayer tube is a mixture consisting of 30 to 70% uncatalyzed tube and 30 to 70% catalyzed tube.

Advantageously, said at least one monolayer and/or multilayer tube is a mixture consisting of more than 50% uncatalyzed tube and less than 50% catalyzed tube.

In another embodiment, said recompounding step(s) is (are) carried out without adding a catalyst.

Advantageously, said at least one monolayer and/or multilayer tube is catalyzed.

Advantageously, said at least one tube is monolayer.

Advantageously, said at least one tube is multilayer.

Advantageously, the composition is degassed during compounding.

For example, it is carried out according to the following protocol A: the reground tube is recompounded on a Coperion/Werner® 40 mm twin-screw extruder, 70 kgh, 300 rpm, 270° C. set point, with degassing of −100 mmHg.

For example, it is performed according to the following protocol B: Tl the reground tube is recompounded on a Coperion/Werner® 40mm twin-screw extruder, 70kg/h, 300rpm, 270°C setpoint, with strong degassing of -660mmHg.

Advantageously, the degassing is located just after the melting zone in the extruder. If the composition of the layer (1) consists of less than 100% recycled material, it is then necessary to add a polyamide (identical or different) of non-recycled origin to the material to be recycled and this can be done when passing through the extruder at least once or else by prior compounding of the granules obtained above with said polyamide of non-recycled origin.

In another embodiment, at least one recompounding step is performed under low outgassing.

In another embodiment, at least one recompounding step is carried out under strong degassing.

In one embodiment, a step of extruding the crushed and recompounded tube is carried out to obtain the tubular structure.

In a first variant, the extrusion step is carried out after the recompounding with or without addition of catalyst.

In a second variant, the extrusion step is carried out after the recompounding with or without addition of catalyst under degassing, in particular under weak or strong degassing, more particularly under strong degassing.

Advantageously, the method according to the invention comprises the following steps:

1) Grinding of a used single-layer and/or multi-layer tube, catalyzed or not, and optional addition of granules (or shredded material) of unused virgin material,

2) recompounding of said crushed tube with addition of a catalyst if said tube is not catalyzed, or without addition of catalyst if said tube is catalyzed in an extruder,

3) optional addition of a catalyzed or uncatalyzed polyamide, in particular catalyzed during the recompounding in the extruder to have a proportion of recycled polyamide of at least 30%, in particular of at least 50% with respect to the total quantity polyamide,

4) optionally degassing, in particular weak or strong degassing, in particular strong degassing, during the recompounding,

5) cooling of the rod at the exit of the extruder and cutting into granules,

6) optionally recompounding said granules cut in the extruder with a polyamide catalyzed in the extruder to have a proportion of recycled polyamide of at least 30%, in particular of at least 50% with respect to the total quantity of polyamide if the step 4) is missing, 7) optionally cooling the rod at the extruder outlet and cutting into granules.

All the technical characteristics detailed above both for the layer (1) and for the recycled tube are valid for the process.

Regarding the use

According to another aspect, the present invention relates to the use of at least one monolayer and/or multilayer tube which has been intended for the transport of fluids for automobiles, in particular as defined above, said at least one monolayer tube and/or or multilayer consisting of a composition which mainly comprises at least one catalyzed or non-catalyzed polyamide, said at least one monolayer and/or multilayer tube having undergone grinding then at least one recompounding with or without addition of at least one catalyst in order to be able to be recycled, simple single grinding being excluded, for the preparation of a single-layer tubular structure intended for the transport of automotive fluids, in particular air, oil, water, a urea solution, a glycol-based cooling liquid, or a fuel such as gasoline, in particular alcoholic gasoline, bio-gasoline or diesel, in particular bio-diesel, or hydrogen, consisting a layer (1) consisting of a composition mainly comprising at least one catalyzed semi-crystalline aliphatic polyamide, said composition consisting of at least 30% by weight, in particular of at least 50% of recycled material from said monolayer and/or multilayer pipe.

All the technical characteristics detailed above both for the layer (1) and for the recycled tube and the process are valid for use.

Brief description of figures:

[Fig. 1] presents the Fourier transform infrared (FTIR) analysis in attenuated total reflectance (ATR) mode of a crushed ELV gasoline line PA 1 1 PL (solid gray line), and compared to a line PA 1 1 PL gasoline based on 100% virgin material (continuous black line).

EXAMPLES:

The following resins were used in the various compositions of the invention: Catalyzed PA11: Polyamide 11 of Mn (number molecular weight) 29,000. The melting temperature is 190° C., its melting enthalpy cb is 56 kJ/m2. The composition of this PA11 includes 0.25% (+/-0.05%) of H3PO4. Uncatalyzed PA12: Polyamide 12 of Mn (number molecular weight) 35000.

The melting temperature is 178°C, its melting enthalp is 54kJ/m2

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

The following additives, plasticizers and impact modifiers were used in the compositions of the invention: stabilizer: stabilizer consisting of 80% Lowinox® 44B25 phenol from Great Lakes, 20% Irgafos® 168 phosphite from Ciba

BBSA: plasticizer BBSA (benzyl butyl sulfonamide),

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

Throughout the description all percentages are given by weight.

In the case of the compositions called "recy", "recy2" and "recy2bis" used for the layer (1) of the tubes of the invention or of the counterexample tubes, the polyamides come from gasoline lines that have been taken from ELVs.

The inherent viscosity according to ISO 307:2007 in m-cresol at 20°C was initially determined on the tubes before use.

Protocol A: After sampling on VHU, the ground tube is recompounded on a Coperion/Werner 40 mm twin-screw extruder, 70 kg/h, 300 rpm, 270° C. set point, with or without the addition of catalyst.

The inherent viscosity of the tube is then determined.

Protocol B: After sampling on VHU, the ground tube is recompounded on a Coperion/Werner 40 mm twin-screw extruder, 70 kg/h, 300 rpm, 270° C. set point, with or without addition of catalyst and with strong degassing of -660 mmHg.

The inherent viscosity of the tube is then determined.

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

PA1 1 PL cat = PA1 1 catalyzed + 7% BBSA + 1% stabilizer

PA12PL = uncatalyzed PA12 + 12% BBSA + 1% stabilizer

PA12PL cat = catalyzed PA12 + 12% BBSA + 1% stabilizer

The different molar ratios presented below were measured by proton NMR in dichloromethane-d2, adding HFIP (hexafluoroisopropanol) to solubilize the polyamide.

PA1 1 PL-recy = tube of PA11 PL cat collected on VHU, reground only. The molar ratio of primary amide functions to secondary amide functions is of 0.02, that of the nitrile functions relative to the secondary amide functions is 0.05, that of the methyl functions relative to the secondary amide functions is 0.004.

PA11 PL-recy2 = tube of PA11 PL cat collected on VHU, reground, recompounded according to protocol A, without addition of catalyst during this recompounding. The molar ratio of primary amide functions relative to secondary amide functions is 0.02, that of nitrile functions relative to secondary amide functions is 0.05, that of methyl functions relative to secondary amide functions is 0.004. PA12PL-recy2 = tube of PA12PL collected on VHU, reground, recompounded according to protocol A, without addition of catalyst during this recompounding. The molar ratio of primary amide functions to secondary amide functions is 0.03, that of nitrile functions to secondary amide functions is 0.07, that of methyl functions to secondary amide functions is 0.01 . PA12PL-recy2bis = tube of PA12PL collected on VHU, reground, recompounded according to protocol A, with addition of catalyst during this recompounding. The molar ratio of primary amide functions to secondary amide functions is 0.03, that of nitrile functions to secondary amide functions is 0.07, that of methyl functions to secondary amide functions is 0.01 . PA12PL-cat-recy2 = tube of PA12PL-cat collected on VHU, reground, recompounded according to protocol A, without addition of catalyst during this recompounding. The molar ratio of primary amide functions to secondary amide functions is 0.03, that of nitrile functions to secondary amide functions is 0.07, that of methyl functions to secondary amide functions is 0.01 .

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.).

Monolayer tubes of the invention: the tubes are 8*1 mm in size

Preparation of single-layer structures (tubes):

Monolayer structures are made by extrusion. A Maillefer industrial multilayer extrusion line is used, equipped with 5 extruders, connected to a multilayer extrusion head with spiral mandrels.

The screws used are single extrusion screws with screw profiles adapted to polyamides. In addition to the 5 extruders and the extrusion head, the extrusion line includes: a die-punch assembly, located at the end of the extrusion head; the internal diameter of the die and the external diameter of the punch are chosen according to the structure to be made and the materials of which it is made, as well as the dimensions of the tube and the line speed; a vacuum tank with an adjustable vacuum level. In this tank circulates water maintained at 20 ° C in general, in which is immersed a gauge allowing to conform the tube in 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; a succession of cooling tanks in which water is maintained at around 20° C., allowing the tube to be cooled along the length of its course from the head to the drawing bench; a diameter gauge; a draw bench.

The 5 extruder configuration is used to produce tubes ranging from 2 layers to 5 layers as well as single layer tubes.

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 stage of drying the material is carried out before the tests, generally in a vacuum dryer, for 1 night at 80°C.

The tubes, which meet the characteristics described in this patent application, were sampled, after stabilization of the extrusion parameters, the dimensions of the targeted tubes no longer changing over time. The diameter is controlled by a laser diameter gauge installed at the end of the line.

Line speed is typically 20m/min. It generally varies between 5 and 100m/min.

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

In general, the temperatures of the extruders and the tools (head and connection) must be adjusted so as to be sufficiently higher than the melting temperature of the compositions under consideration, so that they remain in the molten state, thus avoiding they solidify and block the machine.

The single-layer tubes made by extrusion above were then evaluated on several criteria:

The results are shown in Table 1. [Tables 1]

The inherent viscosity was determined according to ISO 307:2007 in m-cresol at 20°C on 10 tubes for each example.

Table 1 shows that the grinding followed by a recompounding without addition of catalyst for a catalyzed polyamide and collected on VHU makes it possible to find the original inherent viscosity and therefore the qualities of the original tube whereas a simple grinding does not allow not to regain the original inherent viscosity.

It also shows that grinding followed by recompounding without adding catalyst for an uncatalyzed polyamide collected on an ELV does not make it possible to recover the original inherent viscosity and therefore the qualities of the original tube.

Claims

33 CLAIMS

1. Composition mainly comprising at least one catalyzed semi-crystalline aliphatic polyamide, said composition consisting of at least 30% by weight, in particular of at least 50% of recycled material originating from at least one single-layer tube and/or multilayer having been intended for the transport of automotive fluids, in particular such as air, oil, water, a urea solution, a coolant based on glycol, a fuel such as gasoline, in particular bio-gasoline or diesel, in particular bio-diesel, or hydrogen, said at least one single-layer and/or multi-layer tube consisting of a composition which comprises predominantly at least one catalyzed or non-catalyzed polyamide, said at least one single-layer and/or multi-layer tube having undergone grinding then at least one recompounding with or without addition of at least one catalyst in order to be able to be recycled, simple single grinding being excluded, said polyamide of said tube having been intended for the transport of automotive fluids having functions resulting from oxidation reactions chosen from among imide functions, carboxylic acids, primary amides, alcohols and mixtures thereof, in a higher molar ratio with respect to secondary amide functions to that of the same polyamide constituting an unused tube which has never before transported or contained fluids for a motor vehicle.

2. Composition according to claim 1, characterized in that said molar ratio of the functions resulting from oxidation reactions relative to the secondary amide functions is between 1/10,000 to 1/20.

3. Composition according to claim 1 or 2, characterized in that said molar ratio of the imide functions relative to the secondary amide functions is between 1/1000 to 1/20, in particular from 1/500 to 1/20, in particular from 1/200 to 1/50.

4. Composition according to one of claims 1 to 3, characterized in that said molar ratio of the carboxylic acid functions relative to the secondary amide functions 34 is comprised from 1/5000 to 1/20, in particular from 1/3000 to 1/25, in particular from 1/3000 to 1/50, very advantageously comprised from 1/500 to 1/25.

5. Composition according to one of claims 1 to 4, characterized in that said molar ratio of alcohol functions relative to secondary amide functions is between 1/1000 and 1/20 and advantageously between 1/1000 and 1/25 very advantageously comprised from 1/200 to 1/50.

6. Composition according to one of claims 1 to 5, characterized in that it consists of at least 50% recycled material from at least one monolayer and / or multilayer tube having been intended for the transport of fluids for automobile.

7. Monolayer tubular structure 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, consisting of a layer (1) consisting of a composition such as defined in one of claims 1 to 6.

8. Monolayer tubular structure according to claim 7, in which said at least one monolayer and/or multilayer tube consists of a composition which mainly comprises at least one catalyzed polyamide, said at least one monolayer and/or multilayer tube having undergone grinding then at least one recompounding without adding a catalyst in order to be able to be recycled.

9. Monolayer tubular structure according to one of claims 7 or 8, wherein said at least one monolayer and / or multilayer tube consists of a composition which mainly comprises at least one catalyzed polyamide, said at least one monolayer tube and / or multilayer having undergone grinding then at least one recompounding with the addition of a catalyst in order to be able to be recycled.

10. Monolayer tubular structure according to one of claims 7 to 9, wherein said composition of the layer (1) is devoid of plasticizer and / or impact modifier.

11 . Single-layer tubular structure according to one of Claims 7 to 10, in which the said composition of the layer (1) comprises at least one compound chosen from plasticizer, an impact modifier and an additive.

12. Monolayer tubular structure according to one of claims 7 to 1 1, wherein the fluid transported by said at least one monolayer and / or multilayer tube is the same as that of said monolayer tubular structure.

13. Monolayer tubular structure according to one of claims 7 to 1 1, wherein the fluid transported by said at least one monolayer and / or multilayer tube is different from that of said monolayer tubular structure.

14. Monolayer tubular structure according to one of claims 7 to 13, wherein said at least one tube is a monolayer tube.

15. Monolayer tubular structure according to one of claims 7 to 13, wherein said at least one tube is a multilayer tube

16. Monolayer tubular structure according to one of claims 7 to 15, in which the Tm of the predominant aliphatic semi-crystalline polyamide of the layer (1) is <225°C, in particular <200°C as determined by DSC according to standard 60 11357-3:2013, at a heating rate of 20K/min.

17. Monolayer tubular structure according to one of claims 7 to 16, in which the predominant aliphatic semi-crystalline polyamide of the layer (1) has an enthalpy of crystallization > 25 J/g, preferentially > 40 J/g, in particular > 45 J/g as determined by DSC according to ISO 1 1357-3:2013, at a heating rate of 20 K/min.

18. A method of manufacturing a single-layer tubular structure as defined in claim 7, comprising a step of grinding and at least one step of recompounding at least one single-layer and/or multi-layer tube having been intended for the transport of fluids for automobile as defined in claim 1 .

19. Process according to claim 18, in which at least one recompounding stage is carried out with the addition of a catalyst.

20. Process according to claim 19, in which said at least one monolayer and/or multilayer tube is uncatalyzed.

21. Process according to claim 19, in which said at least one monolayer and/or multilayer tube is a mixture consisting of more than 50% uncatalyzed tube and less than 50% catalyzed tube.

22. Process according to claim 18, in which the said step(s) of recompounding is (are) carried out without addition of a catalyst.

23. Process according to claim 22, in which said at least one monolayer and/or multilayer tube is catalyzed.

24. Method according to one of claims 17 to 22, in which at least one recompounding step is carried out under strong degassing.

25. Method according to one of claims 17 to 23, in which a step of extruding the crushed and recompounded tube is carried out to obtain the tubular structure.

26. Use of at least one single-layer and/or multi-layer tube having been intended for the transport of fluids for motor vehicles as defined in claim 1, for the preparation of a single-layer tubular structure intended for the transport of fluids for motor vehicles, in particular air, oil, water, urea solution, glycol-based coolant, or fuel such as gasoline, especially alcoholic gasoline, biogasoline or diesel, in particular biodiesel, or hydrogen as defined in claim 7.