FR3141944A1 - INJECTION MOLDING COMPOSITIONS COMPRISING RECYCLED POLYAMIDES FROM OIL OR GAS DEVELOPMENT, UNDER THE SEA OR LAND. - Google Patents

Abstract

The present invention relates to a molding composition comprising by weight: a) from 35 to 100%, in particular from 35 to 91.9, of at least one semi-crystalline aliphatic polyamide PA1 comprising at least 30%, in particular at least 50 % of recycled semi-crystalline aliphatic polyamide PA2 from pipes for exploiting oil or gas deposits under the sea or on land, in particular under the sea, used or at the end of its life, said recycled semi-crystalline aliphatic polyamide PA2 having underwent a washing and/or compounding step after removal and grinding into granules from said pipe; b) from 0 to 65%, in particular 5 to 50%, of at least one reinforcing fiber; c) from 0 to 40%, in particular from 3 to 30%, of at least one impact modifier; d) from 0 to 30%, in particular 0 to 15% of a filler, e) from 0 to 10%, in particular from 0.1 to 5% of at least one additive, the sum of components a + b + c + d + e is equal to 100%.

Description

INJECTION MOLDING COMPOSITIONS COMPRISING RECYCLED POLYAMIDES FROM OIL OR GAS DEVELOPMENT, UNDER THE SEA OR LAND.

The present invention relates to injection molding compositions comprising recycled polyamides from the exploitation of oil or gas deposits, under the sea or on land.

In the exploitation of oil or gas deposits under the sea (off-shore) or on land (on-shore) it is necessary to use flexible pipes to connect the different devices around the platform. These pipes must withstand hot oil, gas, water and mixtures of two or more of these products for periods of up to 20 years. These pipes are generally made up of a non-sealed inner metallic layer formed by a profiled metal strip wound into a helix such as a stapled strip and which gives the shape to the pipe, then on this layer a polymer is extruded to give the waterproofing and finally other layers of protection and reinforcement are added such as layers of metal fibers and rubbers.

Long-chain polyamides have been used for years for the exploitation of oil or gas deposits, undersea or on land.

However, it is necessary to clean these hoses by circulating methanol through them, for example, to remove hydrates. The disadvantage of methanol is that it penetrates strongly into polyamide. There are therefore losses of methanol but it can also extract the plasticizer and/or modifiers from the polyamide which leads to a degradation of the mechanical properties and premature aging of the hose.

In addition, several tens to hundreds of tons of long-chain polyamides from oil or gas field exploitation pipes, under the sea or on land (respectively offshore or onshore pipes) will have to be recycled in the coming years due to the fact that they have reached the end of their life. However, these polyamides cannot be used after simple grinding due to the pollutants from the extracted oil or gas they contain.

Polyamides (PA) from oil or gas field exploitation pipes, under the sea or on land cannot be used as is.

They must be ground so that they can be transformed into a part with a different shape for a different application.

After grinding, the polyamide to be recycled must also be washed and/or compounded in order to extract a large majority of pollutants (with solvents, melted, under vacuum, etc.). However, the extraction is not necessarily complete.

Without this washing and/or compounding step, the manufactured parts exude. This exudate can be toxic for the user during, for example, the implementation stage and can generate a greasy appearance on the finished parts.

Furthermore, the polyamides to be recycled can be largely hydrolyzed and therefore cannot be extruded. In this case, it is therefore necessary to expose them to a high vacuum (with possible addition of catalyst) to increase their viscosity and make them injectable.

It is therefore necessary to be able to have a composition which does not release harmful gases during the implementation stage and does not exude over time. This allows on the one hand to be injected safely by the manipulator and on the other hand to obtain all types of injected parts stable over time.

The present invention therefore relates to a molding composition comprising by weight:

a) from 35 to 100%, in particular from 35 to 91.9 of at least one semi-crystalline aliphatic polyamide PA1 comprising at least 30%, in particular at least 50% of recycled semi-crystalline aliphatic polyamide PA2 from pipes exploitation of oil or gas deposits under the sea or on land, in particular under the sea, used or at the end of its life, said recycled semi-crystalline aliphatic polyamide PA2 having undergone a washing and/or compounding step after withdrawal and grinding said pipe into granules;

b) from 0 to 65%, in particular 5 to 50%, of at least one reinforcing fiber;

c) from 0 to 40%, in particular from 3 to 30% of at least one impact modifier;

d) from 0 to 30%, in particular 0 to 15% of a charge,

e) from 0 to 15%, in particular from 0.1 to 10%, in particular from 0.5 to 5% of at least one additive,

the sum of the components a + b + c + d + e is equal to 100%.

The inventors have therefore found that the addition of a recycled polyamide PA2 from pipes from exploitation of oil or gas deposits under the sea or on land, in particular under the sea, used or at the end of their life, to a polyamide virgin PA1 made it possible to obtain an injectable composition, having good mechanical properties, exuding little and making it possible to improve the quality and productivity of welds between two parts. injectable. Said composition is implemented in complete safety for the manipulator because it does not emit harmful or toxic gases and makes it possible to obtain all types of injected parts which do not exude or which have low exudation.

The exploitation of oil or gas deposits under the sea or of terrestrial gas uses flexible pipes to connect the different underwater or terrestrial devices respectively of the platform and transporting the extracted hydrocarbons.

These pipes must withstand hot oil, gas, water and mixtures of two or more of these products for periods of up to 20 years.

The term "used" means that the pipe has already been used for the exploitation of oil or gas deposits, whether underwater or on land, but has not yet reached its operating limit of up to 20 years. . The cessation of production of a platform and its dismantling explains the need to recycle this type of pipe which is not yet at the end of its life.

The expression "at the end of its life" means that the pipe has been used for the exploitation of oil or gas deposits, whether underwater or on land, but that it has reached its operating limit until 20 years. These pipes must therefore be removed from the operating system before they are completely degraded or present a sealing problem with respect to the oil or gas being transported.

Regarding semi-crystalline aliphatic polyamide PA1

The PA1 polyamide may be a homopolyamide or a copolyamide or a mixture thereof.

The term semi-crystalline aliphatic polyamide means a material that is generally solid at room temperature, and which softens upon an increase in temperature, in particular after passing its glass transition temperature (Tg), and which can present a clear melting at passage of its so-called melting temperature (Tf), and which becomes solid again upon a decrease in temperature below its crystallization temperature.

Tg, Tc and Tf are determined by differential scanning calorimetry (DSC) according to standard 11357-2:2013 and 11357-3:2013 respectively.

The number average molecular mass Mn of said semi-crystalline polyamide is preferably in a range going from 10,000 to 85,000, in particular from 10,000 to 60,000, preferably from 10,000 to 50,000, even more preferably from 12,000 to 50,000.

The nomenclature used to define polyamides is described in standard ISO 1874-1:2011 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation", in particular on page 3 (tables 1 and 2) and is well known to those skilled in the art.

Said at least one aliphatic semi-crystalline polyamide PA1 can be 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 X with at least one dicarboxylic acid Y or mixtures thereof.

When said at least one aliphatic semi-crystalline polyamide PA1 is obtained from the polycondensation of at least one lactam, said at least one lactam can be chosen from a C6 to C18, C8 to C18, preferably C10 to C18 lactam. , more preferably in C10 to C12. A C6 to C18 lactam includes caprolactam, decanolactam, undecanolactam, and lauryllactam.

When said at least one aliphatic semi-crystalline polyamide PA1 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 PA1 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 PA1 is obtained from the polycondensation of at least one amino acid, said at least one amino acid can be chosen from a C8 to C18 amino acid, preferably from C10 to C18, more preferably from C10 to C12.

A C8 to C18 amino acid is in particular 9-aminononanoic acid, 10-aminodecanoic acid, 10-aminoundecanoic acid, 12-aminododecanoic acid and 11-aminoundecanoic acid as well as its derivatives, in particular the acid N-heptyl-11-aminoundecanoic.

When said at least one aliphatic semi-crystalline polyamide PA1 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 aliphatic semi-crystalline polyamide PA1 is obtained from the polycondensation of a single amino acid and said amino acid is chosen from 10-aminodecanoic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid, advantageously 11-aminoundecanoic acid.

When said at least one aliphatic semi-crystalline polyamide PA1 is obtained from the polycondensation of at least one diamine -C12, more preferably C10-C12 and said aliphatic dicarboxylic acid Y is C6-C36, preferably C6-C18, preferably C6-C12, more preferably C10-C12

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

Said at least one C4-C36 diamine ,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylediamine, 1,13-tridecamethylenediamine, 1,14-tetradecamethylenediamine, 1,16-hexadecamethylenediamine and 1,18 -octadecamethylenediamine, octadecenediamine, eicosanediamine, docosanediamine and diamines obtained from fatty acids.

Advantageously, said at least one diamine ,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine, 1,13-tridecamethylenediamine, 1,14-tetradecamethylenediamine, 1,16-hexadecamethylenediamine and 1,18 -octadecamethylenediamine.

Advantageously, said at least one diamine decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

Advantageously, said at least one diamine decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

Advantageously, the diamine

Said at least one C6 to C36 dicarboxylic acid Y can be chosen from 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 Y 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 Y 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 Y is C10 to C12 and is chosen from sebacic acid, undecanedioic acid, dodecanedioic acid.

When said aliphatic semi-crystalline polyamide PA1 is obtained from the polycondensation of at least one diamine

Advantageously, said aliphatic semi-crystalline polyamide PA1 is obtained from the polycondensation of a single diamine X with a single dicarboxylic acid Y.

In one embodiment, the aliphatic polyamide recycled semi-crystalline PA1 is a long-chain polyamide having an average number of carbon atoms per nitrogen atom greater than 7, in particular greater than 9.

Regarding recycled semi-crystalline aliphatic polyamide PA2

The polyamide PA2 may be a homopolyamide or a copolyamide or a mixture thereof.

The term semi-crystalline aliphatic polyamide means a material that is generally solid at room temperature, and which softens upon an increase in temperature, in particular after passing its glass transition temperature (Tg), and which can present a clear melting at passage of its so-called melting temperature (Tf), and which becomes solid again upon a decrease in temperature below its crystallization temperature.

Tg, Tc and Tf are determined by differential scanning calorimetry (DSC) according to standard 11357-2:2013 and 11357-3:2013 respectively.

The number average molecular mass Mn of said semi-crystalline polyamide is preferably in a range going from 10,000 to 85,000, in particular from 10,000 to 60,000, preferably from 10,000 to 50,000, even more preferably from 12,000 to 50,000.

Said at least one aliphatic semi-crystalline polyamide PA2 was initially obtained before use for the exploitation of oil or gas deposits 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 X with at least one dicarboxylic acid Y or their mixtures as described above for the semi-crystalline aliphatic polyamide PA1.

Advantageously, PA 2 is a PA 11 or PA 12, in particular PA11.

After use, that is to say when it is used or at the end of its life, the pipe for exploiting oil or gas deposits under the sea or on land, in particular under the sea, is removed from the platform operating, the different layers are separated and the layers containing the PA 2 are crushed in the form of ground material (0.5mm to 25mm) or powder (to a size less than 0.5 mm) then washed and/or compounded, c that is to say that the ground material, after washing or not, is introduced 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 fusion , with or without addition of at least one catalyst. The molten material comes out of the extruder in rods which are cooled and cut into pellets.

Advantageously, the compounding number is comprised from 1 to 10, in particular from 1 to 5, in particular the compounding number is from 1, 2, 3, 4 or 5, in particular 1, 2 or 3.

The washing of the ground material when it takes place can be carried out in particular by means of a solvent, in particular methanol, ethanol, in order to extract a large majority of pollutants, such as described below and coming from the exploitation.

Compounding when it takes place can be carried out with the addition of a catalyst.

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

Advantageously, the proportion by weight of catalyst is comprised 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.

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

Advantageously, the present invention therefore relates to the use defined above of at least one catalyst, in proportion by weight of catalyst comprised from approximately 50 ppm to approximately 5000 ppm, in particular from approximately 100 to approximately 3000 ppm relative to to the total weight of the composition, at least one organic or copper thermal stabilizer and at least one chain extender chosen from poly-carbodiimide, poly-maleic anhydride and poly-epoxy, with a matrix comprising at least one thermoplastic polymer, in particular a polyamide, said catalyst being chosen from phosphoric acid (H3PO4), phosphorous acid (H3PO3), hypophosphorous acid (H3PO2), or a mixture of these.

Advantageously, the catalyst is chosen from phosphoric acid (H3PO4), phosphorous acid (H3PO3) in a proportion of approximately 100 to approximately 3000 ppm.

In one embodiment, the PA2 mixture to be recycled is degassed during compounding.

In one embodiment, the outgassing is low, which means that the outgassing is between -50 mmHg and -150 mmHg.

For example it is carried out according to the following protocol A:

the crushed tube, washed or not, is compounded on a Coperion/Werner 40mm twin-screw extruder, 70kgh, 300rpm, 270°C setpoint, with a degassing of -100mmHg.

In another embodiment, the degassing is strong, which means that the degassing is between -550 mmHg and -750 mmHg.

For example, it is carried out according to the following protocol B:

the crushed tube, washed or not, is compounded 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 fusion zone in the extruder.

Advantageously, the inherent viscosity of the semi-crystalline aliphatic polyamide after grinding and washing or after grinding and compounding with or without catalyst, or even after grinding, washing and compounding with or without catalyst, as determined according to ISO 307:2007 in the m- cresol at 20°C is less than 1.6 dl/g dl/g, in particular between 0.9 dl/g and 1.5 dl/g.

The crushed, washed and/or compounded semi-crystalline aliphatic polyamide, with or without catalyst, with or without degassing, therefore corresponds to the recycled semi-crystalline aliphatic polyamide PA2 of the composition of the invention.

In one embodiment, the aliphatic polyamide recycled semi-crystalline PA2 is a long-chain polyamide having an average number of carbon atoms per nitrogen atom greater than 7, in particular greater than 9.

In particular, aliphatic polyamide recycled semi-crystalline PA2 is a long-chain polyamide having an average number of carbon atoms per nitrogen atom of more than 7 to 12, in particular more than 7 to 11, in particular more than 9 to 12, especially more than 9 to 11.

In another embodiment, said aliphatic polyamide recycled semi-crystalline PA2 comprises at least one species chosen from alkanes, aliphatic mono acids from C14 to C18, mono or poly-aromatic compounds and aromatic acids.

Alkanes include methylcyclopentane, cyclohexane, methylcyclohexane, 1,2-cis-dimethylcyclohexane, 1,2-trans-dimethylcyclohexane, 1,3-cis-dimethylcyclohexane, 1,3-trans-dimethylcyclohexane, 1,4-cis-dimethylcyclohexane, 1,4-trans-dimethylcyclohexane, or ethylcyclohexane.

Aliphatic mono acids from C14 to C18 include palmitic acid and stearic acid.

Said aliphatic mono acids from C14 to C18 are also present in the initial virgin semi-crystalline aliphatic polyamide (from 1 to 100 ppm) but are present in higher concentration in the recycled semi-crystalline aliphatic polyamide PA2 (more than 100 ppm), in particular from 500 to 5000 ppm.

Mono or poly-aromatic compounds include toluene, xylene, trimethylbenzene, diphenyl methyl and diphenyl methanol, naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 1,2-dimethylnaphthalene, 1,3 -dimethylnaphthalene, 1,4-dimethylnaphthalene, 1,3,6-trimethylnaphthalene, 2,3,5-trimethylnaphthalene, 1-phenanthrene, 2-methyl phenanthrene.

Aromatic acids include benzoic acid, 2-methylbenzoic acid, 3-methylbenzoic acid, 4-methylbenzoic acid, 2,5-dimethylbenzoic acid, 3,4-dimethylbenzoic acid, 2,4-dimethylbenzoic acid and 3,5-dimethylbenzoic acid.

Advantageously, said aliphatic polyamide recycled semi-crystalline PA2 comprises at least one species chosen from sulfur compounds, alkanes, aliphatic mono acids from C14 to C18, mono or poly-aromatic compounds and aromatic acids.

More advantageously, said aliphatic polyamide semi-crystalline recycled PA2 comprises at least one species chosen from alkanes, mono or poly-aromatic compounds and aromatic acids.

Even more advantageously, said aliphatic polyamide semi-crystalline recycled PA2 comprises at least one species chosen from alkanes and mono or poly-aromatic compounds.

Advantageously, said aliphatic polyamide recycled semi-crystalline PA2 comprises at least one species chosen from alkanes such as methylcyclopentane, cyclohexane, methylcyclohexane, 1,2-cis-dimethylcyclohexane, 1,2-trans-dimethylcyclohexane, 1,3-cis- dimethylcyclohexane, 1,3-trans-dimethylcyclohexane, 1,4-cis-dimethylcyclohexane, 1,4-trans-dimethylcyclohexane, or ethylcyclohexane and mono or poly-aromatic compounds such as toluene, xylene, trimethylbenzene, diphenyl methyl and diphenyl methanol, naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 1,2-dimethylnaphthalene, 1,3-dimethylnaphthalene, 1,4-dimethylnaphthalene, 1,3,6 -trimethylnaphthalene, 2,3,5-trimethylnaphthalene, 1-phenanthrene, 2-methyl phenanthrene.

In one embodiment, the mass content of said species present in the recycled semi-crystalline aliphatic polyamide PA2 is comprised from 100 ppm to 2000 ppm, in particular from 100ppm to 1000ppm.

In another embodiment, the recycled semi-crystalline aliphatic polyamide PA2 has a characteristic odor including the sulfur/pyrogenic and/or hydrocarbon and/or aromatic, terpene and phenol poles.

The odors above are determined according to the description of the field of odors® by Jean-Noël Jaubert.

The field of odors, developed in 1983, provides, among other things, a methodology which makes it possible to describe olfactory perceptions in a common way, that is to say by excluding, as much as possible, individual evocations. It was created by researcher Jean-Noël Jaubert from the results of a research program on the chemical structure/odorant activity relationship of molecules present in the odorous world. Initially developed in the perfume sector, this method made it possible to describe, analyze, compare and control complete products or odorous preparations beyond the usual classifications.

Discomfort linked to odor problems is a signature of recycled polyamide.

This discomfort is perceived when opening the containers of washed or unwashed ground material, or during extrusion and possibly on the finished product.

Recycled polyamides have sulfur or aromatic odorous poles (aromatic solvent smell, naphthalene). You can clearly feel a difference between a virgin polyamide and a recycled polyamide

In yet another embodiment, the recycled semi-crystalline aliphatic polyamide PA2 has functions resulting from thermolysis reactions in an acid medium, in particular amide functions and/or methylene in alpha of said amide functions and the end of acid chains, chosen from the nitrile functions, ketones, and ester functions resulting from reaction of the acid functions of the polyamide with alcohols used during the life of said pipes, in a molar ratio relative to the amide functions greater than that of the same polyamide constituting an unused pipe.

In one embodiment, the molar ratio of the functions resulting from thermolysis reactions is comprised from 1/10,000 to 1/20 as determined by proton NMR or by mass spectrometry after extraction or hydrolysis in an acid medium then analysis by GC/ MS in Electronic Impact.

Concentrations can be measured by proton NMR in dichloromethane-d2, by adding HFIP (hexafluoroisopropanol) to solubilize the polyamide.

During oil extraction, alcohols are used (in the service tube) such as ethanol which can react with the acid functions of the semi-crystalline aliphatic polyamide initially present to lead to ester functions.

In one embodiment, said aliphatic polyamide recycled semi-crystalline PA2 comprises a level of cyclic oligomers, chosen from oligomers having a molar mass less than 1000 g/mol, lower than that of the equivalent virgin polyamide.

The level of cyclic oligomers is measured according to the following protocol:

Aliphatic polyamide granules semi-crystalline recycled PA2 are dissolved in a mixture HFIP (CAS RN 920-66-1)/CH2Cl2 (CAS RN 75-09-3) then a non-solvent (methanol CAS RN 67-56-1) is added. Low molar masses are thus solubilized and high molar masses precipitate.

This solution is filtered at 200 µm before injection. The oligomers are evaluated as lactam 12 equivalents by reversed-phase liquid chromatography coupled with a mass spectrometer using positive electrospray ionization. Formic acid is added to improve ionization.

A peak distribution is observed because of the different molar masses (from monomer to pentamer with linear or cyclic forms).

The polyamide, due to the transport of fluid on the one hand and when washed on the other hand, presents fewer oligomers than the same virgin semi-crystalline aliphatic polyamide because said transport and washing extract the cyclic oligomers.

Advantageously, said aliphatic polyamide semi-crystalline recycled PA2 comprises a level of cyclic oligomers, chosen from oligomers having a molar mass less than 1000 g/mol, less than 90% by weight, in particular less than 50% by weight, in particular less than 20% by weight , in particular less than 10% by weight, compared to that of the equivalent virgin polyamide.

Advantageously, said recycled semi-crystalline aliphatic polyamide PA2 comprises a level of linear oligomer higher than that of a virgin PA.

The level of cyclic oligomer by weight in a virgin polyamide is comprised from 500 to 10,000 ppm for each cyclic species ranging from the monomer to the pentamer (preferably having a mass less than 1000 gmol-1), the cyclic dimer being in particular the majority species.

In particular, the level of cyclic oligomer with a mass of less than 1000 gmol-1 is a maximum of 4% by weight in the virgin polyamide.

In one embodiment, said aliphatic polyamide semi-crystalline recycled PA2 comprises a level of cyclic oligomers having a molar mass less than 1000 g/mol, comprised from 50 to 5000 ppm for each cyclic species ranging from monomer to pentamer, but in any case, it is lower to that of equivalent virgin polyamide.

The level of linear oligomer by weight in a virgin polyamide is between 200 and 2,000 ppm for each linear species ranging from monomer to pentamer (preferably having a mass less than 1000 gmol-1).

In one embodiment, said aliphatic polyamide semi-crystalline recycled PA2 comprises a level of linear oligomers having a molar mass less than 1000 g/mol, comprised from 250 to 5000 ppm for each cyclic species ranging from monomer to pentamer, but in any case, it is higher to that of equivalent virgin polyamide.

In one embodiment, said aliphatic polyamide recycled semi-crystalline PA2 comprises a rate of alkyl chain ends by weight, comprised from 1 ppm to 5000 ppm, advantageously 10 to 2500 ppm, said alkyl being C1 to C18 and said rate being greater than that of an aliphatic polyamide virgin semi-crystalline.

Regarding the composition

In a first variant, the molding composition according to the invention comprises by weight:

a) from 35 to 100%, in particular from 35 to 91.9 of at least one aliphatic polyamide semi-crystalline PA1 comprising at least 30%, in particular at least 50%, of aliphatic polyamide recycled semi-crystalline PA2 from pipes for exploiting oil or gas deposits under the sea or on land, in particular under the sea, used or at the end of its life, said recycled semi-crystalline aliphatic polyamide PA2 having undergone a step of washing and/or compounding after removal and grinding into granules of said pipe;

b) from 0 to 65%, in particular from 5 to 50%, of at least one reinforcing fiber;

c) from 0 to 40%, in particular from 3 to 30% of at least one impact modifier;

d) from 0 to 30%, in particular 0 to 15% of a charge,

e) from 0 to 10%, in particular from 0.1 to 5% of at least one additive,

the sum of components a + b + c + d + e is equal to 100%.

Said composition is an injection molding composition and is not an extrusion composition.

In a first embodiment of this first variant, said molding composition according to the invention comprises by weight:

a) from 35 to 95%, in particular from 35 to 91.9 of at least one aliphatic polyamide semi-crystalline PA1 comprising at least 30%, in particular at least 50%, of aliphatic polyamide recycled semi-crystalline PA2 from pipes for exploiting oil or gas deposits under the sea or on land, in particular under the sea, used or at the end of its life, said recycled semi-crystalline aliphatic polyamide PA2 having undergone a step of washing and/or compounding after removal and grinding into granules of said pipe;

(b) from 5 to 50% of at least one reinforcing fiber;

c) from 0 to 40%, in particular from 3 to 30% of at least one impact modifier;

d) from 0 to 30%, in particular 0 to 15% of a charge,

e) from 0 to 10%, in particular from 0.1 to 5% of at least one additive,

the sum of the components a + b + c + d + e is equal to 100%.

In a second embodiment of this first variant, said molding composition according to the invention comprises by weight:

a) from 35 to 97%, in particular from 35 to 91.9 of at least one aliphatic polyamide semi-crystalline PA1 comprising at least 30%, in particular at least 50%, of aliphatic polyamide recycled semi-crystalline PA2 from pipes for exploiting oil or gas deposits under the sea or on land, in particular under the sea, used or at the end of its life, said recycled semi-crystalline aliphatic polyamide PA2 having undergone a step of washing and/or compounding after removal and grinding into granules of said pipe;

b) from 0 to 65%, in particular from 5 to 50%, of at least one reinforcing fiber;

c) from 3 to 30% of at least one impact modifier;

d) from 0 to 30%, in particular 0 to 15% of a charge,

e) from 0 to 10%, in particular from 0.1 to 5% of at least one additive,

the sum of the components a + b + c + d + e is equal to 100%.

In a third embodiment of this first variant, said molding composition according to the invention comprises by weight:

a) from 35 to 99.9, in particular from 35 to 91.9%, of at least one aliphatic polyamide semi-crystalline PA1 comprising at least 30%, in particular at least 50%, of aliphatic polyamide recycled semi-crystalline PA2 from pipes for exploiting oil or gas deposits under the sea or on land, in particular under the sea, used or at the end of its life, said recycled semi-crystalline aliphatic polyamide PA2 having undergone a step of washing and/or compounding after removal and grinding into granules of said pipe;

b) from 0 to 65%, in particular 5 to 50%, of at least one reinforcing fiber;

c) from 0 to 40%, in particular from 3 to 30% of at least one impact modifier;

d) from 0 to 30%, in particular 0 to 15% of a charge,

e) from 0.1 to 5% of at least one additive,

the sum of the components a + b + c + d + e is equal to 100%.

Advantageously, in this first variant and its three embodiments, said composition consists of said constituents.

In a second variant, said molding composition comprises by weight:

a) from 35 to 92%, in particular from 35 to 91.9, of at least one aliphatic polyamide semi-crystalline PA1 comprising at least 30%, in particular at least 50%, of aliphatic polyamide recycled semi-crystalline PA2 from pipes for exploiting oil or gas deposits under the sea or on land, in particular under the sea, used or at the end of its life, said recycled semi-crystalline aliphatic polyamide PA2 having undergone a step of washing and/or compounding after removal and grinding into granules of said pipe;

(b) from 5 to 50% of at least one reinforcing fiber;

c) from 3 to 30% of at least one impact modifier;

d) from 0 to 30%, in particular 0 to 15% of a charge,

e) from 0 to 10%, in particular from 0.1 to 5% of at least one additive,

the sum of the components a + c + d + e is equal to 100%.

In one embodiment of this second variant, said molding composition according to the invention comprises by weight:

a) from 35 to 91.9 of at least one aliphatic polyamide semi-crystalline PA1 comprising at least 30%, in particular at least 50%, of aliphatic polyamide recycled semi-crystalline PA2 from pipes for exploiting oil or gas deposits under the sea or on land, in particular under the sea, used or at the end of its life, said recycled semi-crystalline aliphatic polyamide PA2 having undergone a step of washing and/or compounding after removal and grinding into granules of said pipe;

(b) from 5 to 50% of at least one reinforcing fiber;

c) from 3 to 30% of at least one impact modifier;

d) from 0 to 30%, in particular 0 to 15% of a charge,

e) from 0.1 to 5% of at least one additive,

the sum of the components a + b + c + d + e is equal to 100%.

Advantageously, in this second variant and its embodiment, said composition consists of said constituents.

In a third variant, said molding composition according to the invention comprises by weight:

a) from 35 to 94.9, in particular from 35 to 91.9%, of at least one aliphatic polyamide semi-crystalline PA1 comprising at least 30%, in particular at least 50%, of aliphatic polyamide recycled semi-crystalline PA2 from pipes for exploiting oil or gas deposits under the sea or on land, in particular under the sea, used or at the end of its life, said recycled semi-crystalline aliphatic polyamide PA2 having undergone a step of washing and/or compounding after removal and grinding into granules of said pipe;

(b) from 5 to 50% of at least one reinforcing fiber;

c) from 0 to 40%, in particular from 3 to 30% of at least one impact modifier;

d) from 0 to 30%, in particular 0 to 15% of a charge,

e) from 0.1 to 5% of at least one additive,

the sum of the components a + b + c + d + e is equal to 100%.

In one embodiment of these three variants and embodiments associated with them, said molding composition defined above has a characteristic odor comprising sulfur and/or hydrocarbon and/or aromatic poles according to the description of the field. odors ® by Jean-Noel Jaubert.

In one embodiment of these three variants and embodiments associated with them,

said aliphatic polyamide semi-crystalline PA1 comprises at least 40% aliphatic polyamide semi-crystalline recycled PA2 from pipes from exploitation of oil or gas deposits under the sea or on land, in particular under the sea, used or at the end of their life.

Advantageously, said aliphatic polyamide semi-crystalline PA1 comprises at least 50% of said aliphatic polyamide semi-crystalline recycled PA2.

Advantageously, said aliphatic polyamide semi-crystalline PA1 comprises at least 60% of said aliphatic polyamide semi-crystalline recycled PA2.

Advantageously, said aliphatic polyamide semi-crystalline PA1 comprises at least 70% of said aliphatic polyamide semi-crystalline recycled PA2.

Advantageously, said aliphatic polyamide semi-crystalline PA1 comprises at least 80% of said aliphatic polyamide semi-crystalline recycled PA2.

Advantageously, said aliphatic polyamide semi-crystalline PA1 comprises at least 90% of said aliphatic polyamide semi-crystalline recycled PA2.

In these last six embodiments, said aliphatic polyamide semi-crystalline PA1 consists of said aliphatic polyamide semi-crystalline PA2 in the proportions described.

Concerning the reinforcing fibers (b)

Concerning the reinforcing fibers, these are short fibers, in particular fibers of mineral, organic or plant origin.

Said reinforcing fiber can be sized or unsized.

Said reinforcing fiber can therefore comprise up to 0.1% by weight of a material of an organic nature (thermosetting or thermoplastic resin type) called sizing.

Among the fibers of mineral origin, we can cite carbon fibers, glass fibers, basalt fibers or basalt-based fibers, silica fibers, or silicon carbide fibers for example. Among the fibers of organic origin, we can cite fibers based on thermoplastic or thermosetting polymer, such as semi-aromatic polyamide fibers, aramid fibers or polyolefin fibers for example. Preferably, they are based on an amorphous thermoplastic polymer and have a glass transition temperature Tg greater than the Tg of the polymer or mixture of thermoplastic polymer constituting the pre-impregnation matrix when the latter is amorphous, or greater than the Tf of the polymer or mixture of thermoplastic polymer constituting the pre-impregnation matrix when the latter is semi-crystalline. Among the fibers of plant origin, we can cite natural fibers based on flax, hemp, lignin, bamboo, silk in particular spider silk, sisal, and other cellulosic fibers, in particular viscose. These fibers of plant origin can be used pure, treated or coated with a coating layer, in order to facilitate adhesion and impregnation of the thermoplastic polymer matrix.

Preferably said reinforcing fiber is chosen from glass fibers, carbon fibers, basalt fibers and basalt-based fibers.

More advantageously, said reinforcing fiber is chosen from carbon fibers and glass fibers.

In one embodiment, the reinforcing fibers present in a) are glass fibers.

The glass fibers can be circular or non-circular in section.

A fiber with a circular section is defined as a fiber having at any point of its circumference a distance equal to the center of the fiber and therefore represents a perfect or almost perfect circle.

Any fiberglass that does not present this perfect or almost perfect circle is therefore defined as a fiber with a non-circular section.

Examples of fibers with a non-circular section, without being limited to these, are non-circular fibers, having for example an elliptical, oval or cocoon shape, star fibers, flake fibers, fibers flat, cruciform, a polygon and a ring.

Fiberglass can be:

- either with a circular section with a diameter of between 4 μm and 25 μm, preferably 4 to 15 μm.

- either with a non-circular section with a ratio L/D (L representing the largest dimension of the transverse section of the fiber and D the smallest dimension of the transverse section of said fiber) of 2 to 8, in particular 2 to 4. L and D can be measured by scanning electron microscopy (SEM).

Advantageously, the glass fibers are circular.

The glass fibers are in particular of type E, R, S2, or T. Advantageously the glass fibers are of type E.

Regarding the shock modifier (c):

The shock modifier is present from 0 to 40%, in particular from 3 to 30% of at least one shock modifier.

In one embodiment, it is present from 5 to 20%.

For example, the impact modifiers are polyolefins having a modulus <200 MPa, in particular <100 MPa, as measured according to standard ISO 178:2010, at 23°C or a thermoplastic elastomer.

In one embodiment, the impact modifier is chosen from a polyolefin having a modulus <200 MPa, in particular <100 MPa, functionalized or not, and mixtures thereof.

Polyolefin:

It can be functionalized or non-functionalized or a mixture thereof.

For simplicity, the polyolefin has been designated by (B) and functionalized polyolefins (B1) and non-functionalized polyolefins (B2) have been described below.

A non-functionalized polyolefin (B2) is conventionally a homopolymer or copolymer of alpha olefins or diolefins, such as for example ethylene, propylene, butene-1, octene-1, butadiene. As an example, we can cite:

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

-propylene homopolymers or copolymers.

- ethylene/alpha-olefin copolymers such as ethylene/propylene, EPR (abbreviation of ethylene-propylene-rubber) and ethylene/propylene/diene (EPDM),

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

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 ter polymerized with unsaturated epoxides such as glycidyl (meth) acrylate, or with carboxylic acids or the corresponding salts or esters such as (meth)acrylic acid (this can be totally or partially neutralized by metals such as Zn, etc.) or by carboxylic acid anhydrides such as maleic anhydride. A functionalized polyolefin is for example a PE/EPR mixture, the weight ratio of which can vary widely, for example between 40/60 and 90/10, said mixture being co-grafted with an anhydride, in particular maleic anhydride, according to a grafting rate for example of 0.01 to 5% by weight.

The functionalized polyolefin (B1) can be chosen from the following (co)polymers, grafted with maleic anhydride or glycidyl methacrylate, in which the grafting rate is for example 0.01 to 5% by weight:

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

- ethylene/alpha-olefin copolymers such as ethylene/propylene, EPR (abbreviation of ethylene-propylene-rubber) and ethylene/propylene/diene (EPDM).

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

- ethylene and vinyl acetate copolymers (EVA), containing up to 40% by weight of vinyl acetate;

- ethylene and alkyl (meth)acrylate copolymers, containing up to 40% by weight of alkyl (meth)acrylate;

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

The functionalized polyolefin (B1) can also be chosen from ethylene/propylene copolymers with a majority of propylene grafted with maleic anhydride then condensed with monoamine polyamide (or a polyamide oligomer) (products described in EP-A-0342066) .

The functionalized polyolefin (B1) may also be a co- or ter polymer of at least the following units: (1) ethylene, (2) alkyl (meth)acrylate or vinyl ester of saturated carboxylic acid and (3) anhydride such as maleic anhydride or (meth)acrylic or epoxy acid such as glycidyl (meth)acrylate.

As an example of functionalized polyolefins of the latter type, the following copolymers may be cited, 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:

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

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

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

In the above copolymers, the (meth)acrylic acid can be salified with Zn or Li.

The term "alkyl (meth)acrylate" in (B1) or (B2) denotes C1 to C8 alkyl methacrylates and acrylates, and can be chosen from methyl acrylate, ethyl acrylate , n-butyl acrylate, iso-butyl acrylate, ethyl-2-hexyl acrylate, cyclohexyl acrylate, methyl methacrylate and ethyl methacrylate.

Furthermore, the aforementioned polyolefins (B1) can also be crosslinked by any appropriate 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 these or mixtures of at least two functionalized polyolefins capable of reacting with each other.

The copolymers mentioned above, (B1) and (B2), can be copolymerized randomly or block-wise and have a linear or branched structure.

The molecular weight, the MFI index, the 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 the ISO 1133 standard at 235°C under 5Kg.

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 higher alpha olefin type comonomer such as butene, hexene, octene or 4-methyl 1-Pentene. We can cite for example PP, high density PE, medium density PE, linear low density PE, low density PE, very low density PE. These polyethylenes are known by those skilled in the art as being produced according to a “radical” process, according to “Ziegler” type catalysis or, more recently, according to so-called “metlocene” catalysis.

Advantageously, the functionalized polyolefins (B1) are chosen from any polymer comprising alpha olefin units and units carrying polar reactive functions such as epoxy, carboxylic acid or carboxylic acid anhydride functions. As examples of such polymers, mention may be made of ter polymers of ethylene, alkyl acrylate and maleic anhydride or glycidyl methacrylate such as Lotader® (SK functional polymer) or polyolefins grafted by maleic anhydride such as Orevac® (SK functional polymer) as well as ter polymers of ethylene, alkyl acrylate and (meth)acrylic acid. Mention may also be made of polypropylene homopolymers or copolymers grafted with a carboxylic acid anhydride then condensed with polyamides or monoamino oligomers of polyamide.

In one embodiment, the polyolefin is crosslinked.

In another embodiment, the polyolefin is a mechanical mixture of an olefinic thermoplastic polymer with a polyethylene or polypropylene matrix and an elastomer, vulcanized such as a vulcanized PP/EPDM mixture.

The thermoplastic elastomer is a block copolymer (ether-amide block copolymer: PEBA), ether-ester block copolymer, a polyurethane thermoplastic: TPU, a styrenic elastomer thermoplastic)

Regarding load (d):

The charge is present from 0 to 30%, in particular 0 to 15% of a charge.

In one embodiment, the charge is present from 1 to 5%.

For example, the fillers can be chosen from silica, graphite, expanded graphite, carbon black, kaolin, magnesia, slag, talc, wollastonite, nanofillers (carbon nanotubes), pigments, metal oxides (titanium oxide), metals, advantageously wollastonite and talc, preferably talc or carbon black.

Regarding additives (e)

The additive is optional and included from 0 to 10.0%, in particular from 0.1 to 5.0% by weight.

The additive is chosen from dyes, stabilizers, plasticizers, surfactants, nucleating agents, pigments, brighteners, antioxidants, lubricants, flame retardants, natural waxes, chain extenders, bases and their mixtures.

Advantageously, the additive is chosen from dyes, stabilizers, plasticizers, surfactants, nucleating agents, pigments, brighteners, antioxidants, flame retardants, natural waxes, chain extenders, bases and their mixtures.

More advantageously, the additive is chosen from dyes, stabilizers, plasticizers, surfactants, nucleating agents, pigments, brighteners, antioxidants, natural waxes, chain extenders, bases and their mixtures.

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 of the company Ciba-BASF), a phosphite type antioxidant (for example irgafos® 126 from the company Ciba-BASF) and even possibly other stabilizers such as a HALS, which means Hindered Amine Light Stabilizer or light stabilizer of the type hindered amine (for example Tinuvin® 770 from the company Ciba-BASF), an anti-UV (for example Tinuvin® 312 from the company Ciba), a phosphorus-based stabilizer. It is also possible to use amine-type antioxidants such as Naugard® 445 from the Crompton company or even polyfunctional stabilizers such as Nylostab® S-EED from the Clariant company.

This stabilizer can also be a mineral stabilizer, such as a copper-based stabilizer. As an example of such mineral stabilizers, mention may be made of copper halides and acetates.

Incidentally, we can possibly consider other metals such as silver, but these are known to be less effective. These copper-based compounds are typically associated with alkali metal halides, particularly potassium.

For example, the plasticizers are chosen from benzene sulfonamide derivatives, such as n-butyl benzene sulfonamide (BBSA); ethyl toluene sulfonamide or N-cyclohexyl toluene sulfonamide; esters of hydroxybenzoic acids, 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 hydroxy-malonic acid, such as oligoethyleneoxy malonate.

It would not be beyond the scope of the invention to use a mixture of plasticizers.

For example, the bases used are zinc or calcium stearates, potash (KOH), sodium hydroxide (NaOH), and magnesium and calcium carbonates.

In one embodiment, the composition according to the invention contains less than 5%, advantageously less than 2%, of plasticizer.

In another embodiment, the composition has an MFI measured according to the ISO 1133 standard at 235°C under 5Kg ranging from 0.5 to 25.

In yet another embodiment, the inherent viscosity of said composition, as determined according to ISO 307:2007 in m-cresol at 20°C is less than or equal to 1.6 dl/g, in particular comprised of 0.8 dl/g to 1.4 dl/g.

According to another aspect, the present invention relates to a process for preparing an aliphatic polyamide recycled semi-crystalline as defined above, characterized in that it comprises, after removal and grinding in the form of used pipe granules or at the end of the life of a platform for exploiting oil or gas deposits under the sea or terrestrial, in particular under the sea, a step of washing and/or compounding said aliphatic polyamide semi-crystalline PA2.

According to another aspect, the present invention relates to the use of a composition as defined above, to prepare articles obtained by extrusion.

According to yet another aspect, the present invention relates to a process for preparing a single-layer or multi-layer pipe, characterized in that it comprises a step of molding a composition as defined above.

Description of figures

presents the field of smells® by Jean-Noel Jaubert

The meaning of the abbreviations used in the is presented in Table 1.

There presents the assembly for carrying out the laser welding described in table 2.

AB= Ambrettolide® AC= Cynnamyl alcohol AM= Isobutylamine AN= Methylanthralylate AP= Phenethyl alcohol AX=Ambroxan® BA= Benzaldehyde BE= Ethylisobutyrate BU= Butyric acid BZ= Benzyl acetate CA= Calone® CD= Cinnamaldehyde CI= Citral CL= Hypochlorite CM= Camphor CO= Coumarin CR= β-caryophyllen CY= Methyl salicylate DC= ϒ-undecanolactone DI= Diacetyl EG= Eugenol EM= Ethylmaltol EV= Evenyl GE= Geosmin HX= cis-3-hexenol LM= d-limoneme LN= Linalool ME= l-menthol MT= Methional NO=Nonanal OC= 1-octen-3-ol OL= trans-anethole PA= Ethyphenylacetate PB= p-hydroxyphenylbutanone PH=Phenom PI= α-pinene PN= cyclopentanone PY= 2-acetylpyrazine QU= Isobutylquinoline SA= Diallyl disulfide SC=Skatole SM= dimethyl disulfide TE= Terpinyl acetate TH= Thymol VA= Vanillin VE= Vetiveryl acetate

EXAMPLES

The invention will now be described in more detail using the following examples which are not limiting.

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

Virgin PA11 = PA11 of Mn 28,000 g/mol + 1% thermal stabilizer (consisting of 0.7% of Lowinox® 44B25 phenol from the company Great Lakes, of 0.3% of phosphite Irgafos® 168 from the company Ciba).

Virgin PA12 = PA12 of Mn 26,000 g/mol + 1% thermal stabilizer (consisting of 0.7% Lowinox® 44B25 phenol from the company Great Lakes, 0.3% phosphite Irgafos® 168 from the company Ciba).

PA11 Recy1 = composition made up of 100% PA11 from offshore pipe crushed into particles ranging in size from 0.5mm to 25mm.

PA11 Recy2 = composition made up of 100% PA11 from offshore pipe crushed into particles ranging in size from 0.5mm to 25mm then washed with methanol by dissolution reprecipitation.

PA11 recy3= composition consisting of 50% PA11 from offshore pipe crushed into particles of size ranging from 0.5mm to 25mm then washed with methanol by dissolution reprecipitation then compounded with 50% virgin PA 11.

PA11 recy4= composition made up of 45% PA11 from offshore pipe crushed into particles of size ranging from 0.5mm to 25mm then washed with methanol by dissolution reprecipitation then compounded with 4.5% virgin PA11, 50% E glass fiber with circular section supplied by Lanxess, 0.5% antioxidants (consisting of 0.35% Lowinox® 44B25 phenol from the company Great Lakes, 0.15% phosphite Irgafos® 168 from the company Ciba).

PA12 recy5= composition made up of 70% PA12 from offshore pipe crushed into particles of size ranging from 0.5mm to 25mm then washed with methanol by dissolution reprecipitation then compounded with 20% virgin PA12, 9.5% Orevac® IM800 shock modifier marketed by SK FP, 0.5% antioxidants (consisting of 0.35% Lowinox® 44B25 phenol from the company Great Lakes, 0.15 % of phosphite Irgafos® 168 from the company Ciba).

The compositions PA11recy3, PA11 recy4 and PA125 recy were prepared by conventional compounding in a co-rotating twin-screw extruder of the Coperion® 40 type, 70kgh, at 300rpm, at 270°C.

The compositions were then molded on an injection press (Engel) at a set temperature of 240°C for the feed and 260°C for the nozzle and a mold temperature of 60°C in the form of 100x100x1 mm ³ plates for exudation measurements. 50x50x2mm ³ plates are produced for laser welding tests.

The plates injected above were then evaluated on several criteria:

The results are shown in Table 2.

Samples Exudation after injection and
Laser welding on injected plates
Shear stress σ
(MPa) EC1 PA12 blank Low (1) 5 EC2 PA11 blank Low (1) 5 EC3 PA 11 Recy1 very strong (5)
(oil residue) 17 EI1 PA 11 Recy2 Low (1) 13 EI2 PA 11 Recy3 Low (1) 12 EI3 PA 11 Recy4 Low (1) 17 EI4 PA 12 Recy Low (1) 14

Exudation is manifested by the appearance of a deposit on the surface and is estimated visually.

Plates are rated from 1 (little exudation) to 5 (a lot of exudation) by trained personnel.

The samples used for the welding tests are samples of 40x10x2mm ³ obtained in injected parts of 50x50x2mm ³ . The samples were cut using a pneumatic press and a cookie cutter. Materials EC2, EC3, EC4, EC5, EI1 and EI2 will be welded to the reference material: EC2. Materials EC1 and EI3 will be welded to the reference material: EC1

The welding is carried out using an LPKF Inlineweld 6200 machine (Garben, Germany) using a 2.1mm diameter spot and a clamping force of 700N. Infrared radiation is produced using a laser diode with a wavelength of 980nm. For each sample, the laser power is 110W and the welding speed is 1000 mm/s.

The quality of the weld is defined by a mechanical test of the two welded parts according to the ASTM D3164-03 standard. In this way, the shear stress indicated in Table 2 is measured.

The compositions of the invention present the best compromise between exudation and shear stress. In particular, the shear stress of the compositions of the invention is greater than that of the comparative compositions EC1 and EC2 and the exudation of the compositions of the invention is lower than that of the comparative composition EC3.

Claims (15)

Molding composition comprising by weight:
a) from 35 to 100%, in particular from 35 to 91.9 of at least one aliphatic polyamide semi-crystalline PA1 comprising at least 30%, in particular at least 50%, of aliphatic polyamide recycled semi-crystalline PA2 from pipes for exploiting oil or gas deposits under the sea or on land, in particular under the sea, used or at the end of its life, said recycled semi-crystalline aliphatic polyamide PA2 having undergone a step of washing and/or compounding after removal and grinding into granules of said pipe;
b) from 0 to 65%, in particular 5 to 50%, of at least one reinforcing fiber;
c) from 0 to 40%, in particular from 3 to 30% of at least one impact modifier;
d) from 0 to 30%, in particular 0 to 15% of a charge,
e) from 0 to 10%, in particular from 0.1 to 5% of at least one additive,
the sum of components a + b + c + d + e is equal to 100%. Molding composition according to claim 1, characterized in that the aliphatic polyamide recycled semi-crystalline PA2 is a long-chain polyamide having an average number of carbon atoms per nitrogen atom greater than 7, in particular greater than 9. Molding composition according to one of claims 1 or 2, characterized in that said aliphatic polyamide recycled semi-crystalline PA2 comprises at least one species chosen from sulfur compounds, alkanes, aliphatic mono acids from C14 to C18, mono or poly-aromatic compounds and aromatic acids. Molding composition according to one of claims 1 to 3, characterized in that said aliphatic polyamide semi-crystalline recycled PA2 comprises at least one species chosen from alkanes, aliphatic mono acids from C14 to C18, mono or poly-aromatic compounds and aromatic acids. Molding composition according to one of claims 1 to 4, characterized in that said aliphatic polyamide semi-crystalline recycled PA2 comprises at least one species chosen from alkanes, mono or poly-aromatic compounds and aromatic acids. Molding composition according to one of claims 1 to 5, characterized in that said aliphatic polyamide recycled semi-crystalline PA2 comprises at least one species chosen from alkanes such as methylcyclopentane, cyclohexane, methylcyclohexane, 1,2-cis-dimethylcyclohexane, 1,2-trans-dimethylcyclohexane, 1,3-cis- dimethylcyclohexane, 1,3-trans-dimethylcyclohexane, 1,4-cis-dimethylcyclohexane, 1,4-trans-dimethylcyclohexane, or ethylcyclohexane and mono or poly-aromatic compounds such as toluene, xylene, trimethylbenzene, diphenyl methyl and diphenyl methanol, naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 1,2-dimethylnaphthalene, 1,3-dimethylnaphthalene, 1,4-dimethylnaphthalene, 1,3,6 -trimethylnaphthalene, 2,3,5-trimethylnaphthalene, 1-phenanthrene, 2-methyl phenanthrene. Molding composition according to one of Claims 3 to 6, characterized in that the mass content of said species present in the recycled semi-crystalline aliphatic polyamide PA2 is between 100 ppm and 2000 ppm, in particular between 100 ppm and 1000 ppm. Molding composition according to one of claims 1 to 7, presenting a characteristic odor comprising the sulfur/pyrogenic and/or hydrocarbon and/or aromatic, terpene and phenolic poles. Molding composition according to one of claims 1 to 8, characterized in that the recycled semi-crystalline aliphatic polyamide PA2 has functions resulting from thermolysis reactions in an acid medium, in particular amide functions and/or methylene in alpha of said amide functions and ends of acid chains, chosen from nitrile functions, ketones, and ester functions resulting from reaction of the acid functions of the polyamide with alcohols used during the life of said pipes, in a molar ratio relative to the amide functions greater than that of the same polyamide constituting an unused pipe. Molding composition according to claim 9, characterized in that the molar ratio of the functions resulting from thermolysis reactions is between 1/10,000 and 1/20 as determined by proton NMR. Molding composition according to one of claims 1 to 10, characterized in that the aliphatic polyamide recycled semi-crystalline PA2 comprises a level of cyclic oligomers chosen from oligomers having a molar mass of less than 1000 g/mol lower than that of the equivalent virgin polyamide. Molding composition according to one of claims 1 to 11, characterized in that the aliphatic polyamide recycled semi-crystalline PA2 comprises a rate of alkyl chain ends, comprised from 1 ppm to 5000 ppm, advantageously 10 to 2500 ppm, said alkyl being C1 to C18 and said rate being greater than that of an aliphatic polyamide virgin semi-crystalline. Process for preparing an aliphatic polyamide recycled semi-crystalline as defined in one of claims 1 to 12, characterized in that it comprises, after removal and grinding in the form of used pipe granules or at the end of the life of an oil field exploitation platform or gas under the sea or on land, in particular under the sea, a step of washing and/or compounding said aliphatic polyamide semi-crystalline PA2. Use of a composition as defined in one of claims 1 to 12, to prepare articles obtained by injection. Process for preparing a single-layer or multi-layer pipe, characterized in that it comprises a step of molding a composition as defined in one of claims 1 to 12.