Recyclable single-material objects comprising at least two elements

Abstract

The present invention relates to a single-material object comprising at least two elements: - at least a first element consisting of a first composition comprising, by weight, at least 30%, in particular at least 50%, in particular at least 70%, more particularly at least 90%, relative to the total weight of the first element, of a copolyamide with amide motifs (Ba1) and polyether motifs (Ba2); - at least a second element consisting of a second composition comprising, by weight, at least 30%, in particular at least 50%, in particular at least 70%, more particularly at least 90%, relative to the total weight of the second element, of a copolyamide with amide motifs (Ba1) and polyether motifs (Ba2), said first and second elements being able to adhere at least partially to each other, said copolyamide of the first composition and said copolyamide of the second composition having a C / N ratio of the motif (Ba1) greater than or equal to 6, in particular greater than or equal to 8.in particular greater than or equal to 9, especially greater than or equal to 10.

Description

Description Title of the invention: Recyclable single-material objects comprising at least two elements technical field

[0001] — This patent application relates to recyclable single-material objects comprising at least two elements, their manufacturing process as well as their process recycling and the compositions thus obtained, as well as their use for the fa- assembly of objects, particularly single-material objects. Previous technique

[0002] The circular economy makes it possible to limit waste production and the depletion of resources. planet's resources and environmental impact. Research is currently underway on particularly to produce objects using materials that will exhibit after recycling of properties sufficient to allow their use for ap- high-performance applications and not only for lower-level applications performance as for street furniture or roads.

[0003] Within the framework of sustainable consumption and production patterns, the ability to recycling of frequently renewed items such as sporting goods and other items E&E and the quality of the resulting recycled products is of paramount importance. particular. However, the performance requirements are particularly high prices for these items.

[0004] It is essential to design objects such as sporting goods and E&E articles so that they can be recycled to produce a material with very good performance. It is also important that the products used for the fa- bric-a-brac of objects are sufficiently stable to be recycled safely. When thermoplastic polyurethanes (TPU) are recycled, the formation Isocyanate is observable by FTIR. Isocyanates are dangerous compounds. CMR...

[0005] = Patent EP 3 081 109 B1 proposes, in order to facilitate their recycling, a shoe of sport in which the upper part and the sole are mostly or even entirely made of the same thermoplastic base material. However, it appears that it Difficulties remain in that the recycled product thus obtained presents limitations in terms of performance due to the density of the shoe's components differs according to their respective function.

[0006] — Patent application WO 2020 / 201370 A1 proposes a method for recycling such as shoes in which the shoe is crushed and then melted. This document is Like its predecessor, it focuses on thermoplastic polyurethanes (TPU). It is indicated in this international request the fact that TPUs degrade with recycling cycles. US application 2017 / 0151470 A1 relates to a ball, in particular a football, a manufacturing process and the recycling of the ball. The ball consists of a bladder, an intermediate layer and an outer layer, the bladder and the two layers being made of a major component by weight of a material from a first class of material selected from polyurethane, polyvinyl chloride, polyethylene, polyamide and polypropylene. International application WO 2021 / 148148 Al relates to a lined garment article comprising an outer layer, an inner layer and a lining between the two layers. Each layer contains a majority of a material from the same family, chosen from among thermoplastic polymers, including recycled polyester or a virgin polymer selected from thermoplastic polyurethanes (TPU), polyamides (PA), polyethylene terephthalate (PET), or polyethylene butylene terephthalate (PBT). Polyesters have the disadvantage of being highly susceptible to hydrolysis. The invention therefore aims to provide a single-material object whose composition is studied in such a way as to allow the recycling of a composition that can be used for applications requiring high performance. However, it has been shown that the exclusive combination (excluding additives and fillers) in a single-material object of a polyamide fraction (element) and a polyamide fraction (element) allows for better maintenance of properties during recycling. Specifically, impact resistance, fatigue resistance, and mechanical properties (modulus, elongation at break, tensile strength, and yield strength) are maintained. Furthermore, density and chemical resistance are also maintained. Indeed, the presence of PEBA, a flexible compound, in both the first and second elements, helps to improve the mechanical resistance of the object throughout its life, before and after recycling. Also, according to a first aspect, the invention relates to a single-material object comprising at least two elements: - at least one first element consisting of a first composition comprising by weight at least 30%, in particular at least 50%, particularly at least 70%, more particularly at least 90%, relative to the total weight of the first element, of a copolyamide with amide motifs (Bal) and polyether motifs (Ba2), - at least a second element consisting of a second composition comprising by weight at least 30%, in particular at least 50%, particularly at least 70%, more particularly at least 90%, relative to the total weight of the second element, of a copolyamide with amide motifs (Bal) and polyether motifs (Ba2), said first and second elements being able to adhere at least partially to one another, said copolyamide of the first composition and said copolyamide of the second composition having a C / N ratio of the amide motif (Bal) greater than or equal to 6, in particular greater than or equal to 8, in particular greater than or equal to 9, in particular greater than or equal to 10. In one embodiment, said object excludes a single-layer or multi-layer structure for the transport, distribution or storage of a fluid and excludes a catheter. The Inventors therefore unexpectedly found that the exclusive combination (excluding additives and fillers) in a single-material object of a first fraction (or element) of a particular block polyether amide pattern copolyamide (PEBA), namely PEBAs having a C / N ratio of the amide pattern (Bal) greater than or equal to 6, in particular greater than or equal to 8, in particular greater than or equal to 9, in particular greater than or equal to 10, and of a second fraction (or element) of a particular block polyether amide pattern copolyamide (PEBA), namely PEBAs having a C / N ratio of the amide pattern (Bal) greater than or equal to 6, in particular greater than or equal to 8, in particular greater than or equal to 9, in particular greater than or equal to 10, allows for better maintenance of properties during recycling. Indeed, the specific polyether block amide (PEBA) copolyamides in both compositions offer the best compromise and provide, in particular, good resistance to aging, thus extending the lifespan of the object and facilitating its recycling process. They can also be recycled safely. Recycled compositions also have the advantage of having low density, good elastic recovery, good shock resistance, good tensile properties, and a stable modulus between -20°C and 30°C. The C / N ratio corresponds to the number of carbon atoms per nitrogen atom in the motif (Bal). By "mono-material object" we mean an object made primarily of the same material. material, in this case a polyamide in the pattern (Bal) having a pattern C / N ratio (Bal) greater than or equal to 6, in particular greater than or equal to 8, in particular greater than or equal to 9, in particular greater than or equal to 10 in both compositions. In one variant, single-material objects can be, but are not limited to, the following: An electronic item, in particular a watch, a phone case, headphones, earphones, a speaker, a keyboard, a mouse, a phone charger, an item of clothing, in particular a jacket, trousers, a t-shirt, etc. socks an optical article, in particular eyeglasses, sunglasses, children's glasses, sports glasses and ski goggles, augmented reality / virtual reality glasses. a household appliance, in particular a small appliance, a household appliance accessory (bowl, mixing paddle, food container), a water bottle, a food container, a cosmetic article, in particular cosmetic packaging such as a bottle, perfume, makeup packaging, skincare packaging, a presentation item, a hairbrush, a sporting item, in particular a surfboard (and its accessories such as leashes or fins), a bicycle, bicycle parts such as saddles or pedals, a helmet, ski boots, skis, ski poles, ski bindings and a snowboard (excluding metal), a golf club, any type of racket, in particular a tennis racket, protective equipment such as shin guards, elbow pads, etc., a hockey stick (field and ice), a rollerblade, diving fins, an item of luggage, in particular a suitcase, a backpack and a handbag stationery items, especially pens. a toy, furniture, and automotive parts. The expression "said object being excluding a single-layer or multi-layer structure for the transport, distribution or storage of a fluid as well as excluding a catheter" means that single-layer or multi-layer structures for the transport, distribution or storage of a fluid, in particular for a device with a thermal or electric motor such as an airplane, a drone, an aircraft, a truck or an automobile are excluded from said object as well as catheters which are medical devices in the form of a thin and flexible tube. In one embodiment of this first variant, single-material objects correspond to all those described in the list of this first variant with the exception of at least one of those described in this same list and excluding a single-layer or multi-layer structure for the transport, distribution or storage of a fluid. It is quite clear that, at a minimum, the said single-material object corresponds to at least one of those described in the said list of this first variant. In a second variant, single-material objects can be an electronic item, a textile item, an optical item, a household appliance, a cosmetic item, a sporting item, a stationery item, a luggage item, a toys, furniture and car parts. In one embodiment of this second variant, single-material objects correspond to all those described in the list of this second variant with the exception of at least one of those described in this same list and excluding a single-layer or multi-layer structure for the transport, distribution or storage of a fluid. It is quite clear that, at a minimum, the said single-material object corresponds to at least one of those described in the said list of this second variant. In a third variant, single-material objects can be an electronic item, a textile item, an optical item, a household appliance, a cosmetic item, a sporting item, a stationery item, a luggage item, a toy, or furniture. In one embodiment of this third variant, single-material objects correspond to all those described in the list of this third variant with the exception of at least one of those described in the same list and excluding a single-layer or multi-layer structure for the transport, distribution or storage of a fluid. It is quite clear that, at a minimum, the said single-material object corresponds to at least one of those described in the said list of this third variant. In one embodiment of these three variants, said object excludes a single-layer or multi-layer structure for the transport, distribution or storage of a fluid and excludes a catheter. The term "fluid" encompasses any gas, in compressed, liquid, or cryocompressed form, and in particular hydrogen, natural gas, LPG, LNG, compressed air, nitrogen, oxygen, as well as a heat transfer fluid, in particular a refrigerant selected from hydrocarbon compounds, hydrofluorocarbons, ethers, hydrofluoroethers, CO2, NH3, SO2, and fluoroolefins, in particular R134a, R-1234yf, or R-1234ze, or a gas used in automobiles, in particular air, or a liquid used in automobiles, in particular water, oil, brake fluid, urea solution, glycol-based coolant, transmission oil cooler (TOC), fuels, in particular diesel, gasoline, and more specifically alcoholic gasoline, or LPG. In one embodiment, a shoe, a ball, a car seat, a backpack, a toothbrush or a jacket are excluded from the single-material objects of the invention. In one embodiment, at least 50% by weight of amide patterned polyamide (Bal) in the copolyamide is present in each of the two elements relative to the total weight of the composition of each element. In other words, the sum by weight of amide patterned polyamide (Bal) in the first element and amide patterned polyamide (Bal) in the second element is at least 50% relative to the total weight of the two compositions of each element. In another embodiment, the matrix of each of the two elements (excluding fillers and additives) consists of 60% by weight, advantageously 80% by weight, preferably 100% by weight of amide patterned polyamide (Bal). The term "element" refers to each of the things whose combination, the union, forms another thing, a whole, namely in the present invention a single-material object. Specifically, an element refers to a component, a constituent, a piece, a part, a unit or a unit that constitutes the single-material object. The expression "the said first and second elements being able to adhere at least partially to one another" means that the said first and second elements may or may not adhere to one another. In one embodiment, said first and second elements are not adhered to each other. In another embodiment, the first and second elements adhere to each other, at least partially, and in particular totally. The term "adhes" means that the said first and second elements are joined to each other or applied against each other, at least partially and in particular by gluing, clipping, overmolding, thermoforming, screwing, sewing, welding or riveting. It is quite clear that the said first and second compositions which include a copolyamide with amide motifs (Bal) and with polyether motifs (Ba2) may also include shock modifiers and / or plasticizers and / or fillers and / or additives. It is quite evident that the said third composition described below, which comprises a homopolyamide and a long-chain copolyamide or a copolyamide with amide motifs (Bal) and polyether motifs (Ba2) or a mixture of the two, may also comprise shock modifiers and / or plasticizers and / or fillers and / or additives. Regarding the copolyamide with amide motifs (Bal) and polyether motifs (Ba2) (PEBA) of the compositions of the first, second element and third element. Poly ether block amide (PEBA) are copolymers with amide (Bal) and polyether (Ba2) motifs, said amide (Bal) motif corresponding to an aliphatic repeating motif chosen from a motif obtained from at least one amino acid or a motif obtained from at least one lactam, or an XY motif obtained from polycondensation: - of at least one diamine, said diamine being preferentially chosen from among a linear or branched aliphatic diamine, or a mixture thereof, and - of at least one dicarboxylic acid, said diacid being preferably chosen from: a linear or branched aliphatic diacid, or a mixture thereof, said diamine and said diacid comprising from 4 to 36 carbon atoms, advantageously from 6 to 18 carbon atoms; said polyether motifs (Ba2) being in particular derived from at least one polyalkylene ether polyol, in particular a polyalkylene ether diol, PEBAs result in particular from the copolycondensation of reactive-ended polyamide sequences with reactive-ended polyether sequences, such as, among others: 1) Polyamide sequences with diamine chain ends with polyoxy-alkylene sequences with dicarboxylic chain ends. 2) Polyamide sequences with dicarboxylic chain ends with polyoxyalkylene sequences with diamine chain ends obtained by cyanoethylation and hydrogenation of aliphatic alpha-omega dihydroxylated polyoxyalkylene sequences called polyalkylene ether diols (polyetherdiols). 3) Polyamide sequences with dicarboxylic acid end-chains and polyetherdiols, the products obtained being, in this particular case, polyetheresteramides. The copolymers of the invention are advantageously of this type. Polyamide sequences with dicarboxylic chain ends originate, for example, from the condensation of polyamide precursors in the presence of a chain-limiting dicarboxylic acid. Polyamide sequences with diamine chain ends originate, for example, from the condensation of polyamide precursors in the presence of a chain-limiting diamine. Polymers with polyamide and polyether block structures can also include randomly distributed motifs. These polymers can be prepared by the simultaneous reaction of polyether and polyamide block precursors. For example, polyetherdiol, polyamide precursors, and a chain-limiting diacid can be reacted. The resulting polymer consists primarily of polyether blocks, polyamide blocks of highly variable length, and also the various reactants that have reacted randomly and are distributed randomly (statistically) along the polymer chain. Polyetherdiamine, polyamide precursors, and a chain-limiting diacid can also be reacted. The resulting polymer consists primarily of polyether blocks, polyamide blocks of highly variable length, and the various reactants that have reacted randomly and are distributed in a statistically random manner. along the polymer chain. Amide pattern (Bal): The amide motif (Bal) corresponds to an aliphatic repeating motif as defined above. The amide motif (Bal) of the copolyamide of the compositions of the first, second element and third element has a C / N ratio greater than or equal to 6, in particular greater than or equal to 8, in particular greater than or equal to 9, in particular greater than or equal to 10. Advantageously, the amide motif (Bal) is chosen from polyamide 11, polyamide 12, polyamide 610, polyamide 612, polyamide 1010, polyamide 910, polyamide 613, polyamide 514, polyamide 109, polyamide 1011, polyamide 516, polyamide 615, polyamide 913, polyamide 129, polyamide 1012, in particular polyamide 11. More advantageously, the amide motif (Bal) is chosen from polyamide 11 and polyamide 12, in particular polyamide 11. Polyether motif (Ba2): The polyether motifs are derived from at least one polyalkylene ether polyol; in other words, the polyether motifs consist of at least one polyalkylene ether polyol. In this embodiment, the expression "of at least one polyalkylene ether polyol" means that the polyether motifs are exclusively composed of alcohol chain ends and therefore cannot be a poly-etherdiamine triblock compound. The composition of the invention is therefore devoid of polyetherdiamine triblock. Advantageously, the polyether motifs (Ba2) are selected from polyethylene glycol (PEG), polypropylene glycol (PPG), polytrimethylene glycol (PO3G), polytetramethylene glycol (PTMG) and their mixtures or copolymers, in particular PTMG. The number-average molecular weight (Mn) of the polyether blocks is advantageously between 200 and 4000 g / mol, preferably between 250 and 2500 g / mol, especially between 300 and 1100 g / mol. PEBA can be prepared by the following process: - In the first step, the polyamide blocks (Bal) are prepared by polycondensation of the lactam(s), or of the amino acid(s), or of the diamine(s) and the dicarboxylic acid(s); and where applicable, of the comonomer(s) chosen from among the lactams and alpha-omega aminocarboxylic acids; in the presence of a chain limiter chosen from among the dicarboxylic acids; then - in a second step, the polyamide blocks (Bal) obtained are reacted with polyether blocks (Ba2), in the presence of a catalyst. The general two-step method for preparing the copolymers of the invention is known and is described, for example, in French patent FR 2 846 332 and in European patent EP 1 482 011. The block formation reaction (Bal) usually takes place between 180 and 300°C, preferably between 200 and 290°C. The pressure in the reactor is established between S and 30 bar and maintained for approximately 2 to 3 hours. The pressure is then slowly reduced by bringing the reactor to atmospheric pressure, and the excess water is distilled, for example, over an hour or two. Once the polyamide with carboxylic acid ends has been prepared, the polyether and a catalyst are added. The polyether and catalyst can be added in one or more stages. In an advantageous approach, the polyether is added first, and the reaction between the OH ends of the polyether and the COOH ends of the polyamide begins, forming ester bonds and eliminating water. As much water as possible is removed from the reaction medium by distillation, and then the catalyst is introduced to complete the bonding of the polyamide and polyether blocks. This second step is carried out under stirring, preferably under a vacuum of at least 15 mmHg (2000 Pa) at a temperature such that the reactants and the resulting copolymers are in a molten state. For example, this temperature can range from 100 to 400°C, and most often from 200 to 300°C.The reaction is monitored by measuring the torque exerted by the molten polymer on the agitator or by measuring the electrical power consumed by the agitator. The end of the reaction is determined by the target torque or power value. One or more molecules used as antioxidants, for example Irganox® 1010 or Irganox® 245, can also be added during synthesis at the most opportune time. The PEBA preparation process can also be considered as such that all the monomers are added at the beginning, either in a single step, to carry out the polycondensation of the lactam(s), or of the amino acid(s), or of the diamine(s) and dicarboxylic acid(s); and where applicable, of the other polyamide comonomer(s); - in the presence of a chain limiter chosen from among the dicarboxylic acids; - in the presence of the (Ba2) (polyether) blocks; - in the presence of a catalyst for the reaction between the soft blocks (Ba2) and the blocks (Bal). Advantageously, the said dicarboxylic acid is used as a chain limiter, which is introduced in excess relative to the staichiometry of the diamine(s). Advantageously, a derivative of a metal chosen from the group formed by titanium, zirconium and hafnium or a strong acid such as phosphoric acid, hypophosphorous acid or boric acid is used as a catalyst. Polycondensation can be carried out at a temperature of 240 to 280°C. In general, copolymers with known ether and amide motifs consist of linear and semi-crystalline aliphatic polyamide sequences (for example, Arkema's "Pebax"). In one embodiment, the amide-patterned (Bal) and polyether-patterned (Ba2) copolyamide has a density greater than or equal to 1, in particular greater than or equal to 1.01, in particular greater than or equal to 1.02, as determined according to ISO 1183-3: 1999. In one embodiment, polyetheramines are excluded from polyether motifs (Ba). Regarding homopolyamide and long-chain copolyamide in the composition of the third element. The nomenclature used to define polyamides is described in ISO 1874-1:2011 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation", particularly on page 3 (tables 1 and 2) and is well known to those skilled in the art. The said homopolyamide and long chain copolyamide is a polyamide having a C / N ratio, that is to say having an average number of carbon atoms per nitrogen atom greater than or equal to 6, in particular greater than or equal to 8, more particularly greater than or equal to 9, notably greater than or equal to 10. In a first embodiment of the invention, the repeating motif is a motif obtained from the polycondensation of at least one amino acid (or aminocarboxylic acid) at C4-C36, Advantageously, the aminocarboxylic acid comprises from 9 to 12 carbon atoms. It can thus be chosen from 9-aminononanoic acid (denoted 9), 10-aminodecanoic acid (denoted 10), 11-aminoundecanoic acid (denoted 11) and 12-aminododecanoic acid (denoted 12), advantageously the aminocarboxylic acid is 11-aminoundecanoic acid. In a second variant of the invention, the repeating motif is a motif obtained from the polycondensation of at least one lactam at C4-C36. Advantageously, lactam comprises 9 to 12 carbon atoms. It can thus be chosen from among caprolactam (denoted 6), decanolactam (denoted 10), undecanolactam (denoted 11), and laurolactam or lauryllactam (denoted 12). lauryllactam. However, it is perfectly possible to implement a mixture of two or more aminocarboxylic acids, a mixture of two or more lactams, but also a mixture of one, two or more aminocarboxylic acids with one, two or more lactams. In a particularly preferred manner, the repeating motif is obtained from a single aminocarboxylic acid or a single lactam. XY repeating pattern The XY repeating motif is a motif obtained from the polycondensation of at least one diamine, said diamine being chosen from a linear or branched aliphatic diamine, a cycloaliphatic diamine and a semi-arylaliphatic diamine, or a mixture thereof, and of at least one dicarboxylic acid, said diacid being chosen from: an aliphatic diacid, a cycloaliphatic diacid and an aromatic diacid or a mixture thereof, The molar proportions of diamine and dicarboxylic acid are preferentially staichiometric. The said diamine comprises from 4 to 36 carbon atoms, advantageously from 6 to 18 carbon atoms. In one embodiment, said diamine comprises from 6 to 12 carbon atoms. In cases where the diamine used to obtain this XY repeating motif is an aliphatic diamine with a linear main chain, this linear main chain may, if present, contain one or more methyl and / or ethyl substituents; in this latter configuration, it is referred to as a "branched aliphatic diamine". In cases where the main chain contains no substituents, the aliphatic diamine is called a "linear aliphatic diamine". Whether or not it contains methyl and / or ethyl substituents on the main chain, the aliphatic diamine used to obtain this XY repeating motif comprises from 4 to 36 carbon atoms, advantageously from 6 to 18 carbon atoms, notably from 9 to 18 carbon atoms. When this diamine is a linear aliphatic diamine, it corresponds to the formula H2N-(CH2)x-NH2 and can be chosen, for example, from butanediamine, pentanediamine, hexanediamine, heptanediamine, octanediamine, nonanediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, hexadecanediamine, octadecanediamine, and octadecenediamine. The linear aliphatic diamines just mentioned can all be bio-sourced according to ASTM D6866. When this diamine is a branched aliphatic diamine, it can notably be 2-methyl-2 pentanediamine, 2-methyl-1,8-octanediamine or trimethylene (2,2,4 or 2,4,4) hexanediamine. Cycloaliphatic diamine can be chosen, for example, from the bis(3,5-dialkyl-4-aminocyclohexyl)-methane, the bis(3,5-dialkyl-4-aminocyclohexyl)ethane, the bis(3,5-dialkyl-4-aminocyclohexyl)-propane, bis(3,5-dialkyl-4-aminocyclohexyl)-butane, bis- (3-methyl-4-aminocyclohexyl)-methane or 3'-Dimethyl-4,4"-diamino-dicyclohexyl-methane commonly referred to as "BMACM" or "MACM" (and denoted B hereafter), p-bis(aminocyclohexyl)-methane commonly referred to as "PACM" (and denoted P hereafter), isopropylidenedi(cyclohexylamine) commonly referred to as "PACP", isophorone-diamine (denoted IPD hereafter) and 2,6-bis(aminomethyl)norbornane commonly referred to as "BAMN" or bis(aminomethyl)cyclohexane commonly referred to as "BAC". A non-exhaustive list of these cycloaliphatic diamines is given in the publication "Cycloaliphatic Amines" (Encyclopaedia of Chemical Technology, Kirk-Othmer, 4th Edition (1992), pp. 386-405). When this diamine is a semi-arylaliphatic diamine, it is for example chosen from 1,3-xylylene diamine and 1,4-xylylene diamine. The dicarboxylic acid comprises from 4 to 36 carbon atoms, advantageously from 6 to 18 carbon atoms, especially from 6 to 12 carbon atoms. When the dicarboxylic acid is aliphatic, it can be chosen from among the aliphatic, linear or branched dicarboxylic acids. When the dicarboxylic acid is aliphatic and linear, it can be chosen from succinic acid (4), pentanedioic acid (5), adipic acid (6), heptanedioic acid (7), octanedioic acid (8), azelaic acid (9), sebacic acid (10), undecanedioic acid (11), dodecanedioic acid (12), brassylic acid (13), tetradecanedioic acid (14), hexadecanedioic acid (16), octadecanedioic acid (18), octadecenedioic acid (18), eicosanedioic acid (20), docosanedioic acid (22) and fatty acid dimers containing 36 carbons. The fatty acid dimers mentioned above are dimerized fatty acids obtained by oligomerization or polymerization of long-chain unsaturated monobasic fatty acids (such as linoleic acid and oleic acid), as described in particular in document EP 0 471 566. When the dicarboxylic acid is aromatic, it can be chosen from terephthalic acid (denoted T), isophthalic acid (denoted I) and a naphthalenic acid (denoted N). In one embodiment, the composition of the first element consists of a single homopolyamide. In another embodiment, the homopolyamide of the composition of the third element is a semi-crystalline aliphatic homopolyamide. A semi-crystalline homopolyamide, in the sense of the invention, designates a material which is generally solid at room temperature, and which softens during an increase in temperature, in particular after passing its glass transition temperature (Tg), and which may exhibit a clear melting when passing its so-called melting temperature (Tf), and which becomes solid again during a decrease in temperature below its crystallization temperature. The semi-crystalline homopolyamide, as defined in the invention, has a melting temperature (Tf) measured according to ISO 11357-3:2013 by DSC, and an enthalpy of crystallization measured during the cooling step at a rate of 20K / min by DSC according to ISO 11357-3:2013 greater than 25 J / g, preferably greater than 40 J / g. Tg, Tc and Tf are determined by differential scanning calorimetry (DSC) according to standards 11357-2:2013 and 11357-3:2013 respectively. The average number molecular weight (Mn) of said semi-crystalline homopolyamide is preferably in a range of 10,000 to 85,000, in particular 10,000 to 60,000, preferably 10,000 to 50,000, and even more preferably 12,000 to 50,000. These Mn values ​​can correspond to inherent viscosities greater than or equal to 0.8 as determined in m-cresol according to ISO 307:2007 but by changing the solvent (using m-cresol instead of sulfuric acid and the temperature being 20°C). Regarding the single-material object It consists of at least two elements: said at least a first element defined here as (El) and said at least a second element defined here as (E2). In a first variant, it consists of two said elements: E1 / E2. Element El can adhere to element E2 at least partially, in particular El and E2 adhere at least partially, in particular El and E2 adhere totally, in particular by means of an adhesive. The single-material object is then chosen from those described above. In a second variant, it consists of more than two elements: El / (E1)n / E2 / (E2)m, n and m being between 0 and 5 and when n=0, then m is greater than 0 and when m=0, then n is greater than 0. It is quite obvious that when two elements El or E2 are side by side, they can adhere at least partially to each other. In one embodiment, the copolyamides of elements E1 and E2 comprise an identical monomer, for example 11-aminoundecanoic acid, in particular at least 5% by weight of an identical monomer relative to the sum of the constituents said copolyamide, advantageously at least 10%, preferably at least 20%. In one embodiment, the polyamide motifs of the copolyamides of elements El and E2 comprise a monomer having an identical C / N ratio, in particular at least 5% by mass of a monomer having an identical C / N ratio with respect to the sum of the constituents of said homopolyamide or copolyamide, advantageously 10%, preferably 30%. In another embodiment, the copolyamides of elements El and E2 comprise the same polyether motif (Ba2), in particular polytetramethylene glycol (PIMG). In yet another embodiment, the copolyamides of elements El and E2 comprise an identical monomer, for example amino-11-undecanoic acid, in particular at least 5% by weight of an identical monomer with respect to the sum of the constituents of said copolyamide, advantageously at least 10%, preferably at least 20%, and the copolyamides of elements El and E2 comprise the same polyether motif (Ba2), in particular polytetramethylene glycol (PTMG). In another embodiment, the polyamide motifs of the copolyamides of elements El and E2 comprise a monomer having an identical C / N ratio, in particular at least 5% by mass of a monomer having an identical C / N ratio with respect to the sum of the constituents of said homopolyamide or copolyamide, advantageously 10%, preferably 30%, and the copolyamides of elements El and E2 comprise the same polyether motif (Ba2), in particular polytetramethylene glycol (PTMG). In one embodiment, the first composition and the second composition comprise the same polyamide motif, in particular a PA11. In another embodiment, said first and second element are chosen from the following constituents: a textile, a film or textured film, a foam, an injected part, an extruded part, a 3D printed part, an adhesive, a non-woven, a veil and a consolidated thermoplastic composite part. Advantageously, the single-material object comprises at least two constituents defined above and which are different. Advantageously, the single-material object comprises at least three constituents defined above, in particular different ones. In another embodiment, the first and second elements adhere to each other by bonding with a non-polyamide adhesive in a content of 0.01% to 10% by weight, in particular 0.1% to 4% by weight relative to the total mass of the object. In a third variant, it may consist of more than two elements: said at least a first element defined here as (E1) and said at least a second element defined here as (E2) and said third element defined here as E3. In one embodiment, it consists of three elements: E1 / E2 / E3 or E1 / F3 / F2 or E3 / E1 / F2. Element El can adhere to element E2 at least partially, in particular El and E2 adhere at least partially, in particular El and E2 adhere totally, in particular by means of an adhesive. Element E2 can adhere to element E3 at least partially, in particular E2 and E3 adhere at least partially, in particular E2 and E3 adhere totally, in particular by means of an adhesive. We would not be going out of the scope of the invention if at least one other element E1 and / or E2 and / or E3 were present in said single-material object. In the first variant, the first element is of non-recycled origin. In a second variant, the second element is of non-recycled origin. In a third variant, the third element, if present, is of non-recycled origin. In a fourth variant, the first element and the second element are of non-recycled origin. In a fifth variant, the first element and the third element when present are of non-recycled origin. In a sixth variant, the second element and the third element when present are of non-recycled origin. In a seventh variant, the first element, the second element and the third element when present are of non-recycled origin. In an eighth variant, the first element is of at least partially recycled origin. In a ninth variant, the second element is at least partially recycled in origin. In a tenth variant, the third element, if present, is of at least partially recycled origin. In an eleventh variant, the first element and the second element are of at least partially recycled origin. In a twelfth variant, the first element and the third element when present are of at least partially recycled origin. In a thirteenth variant, the second element and the third element when present are of at least partially recycled origin. In a fourteenth variant, the first element, the second element and the third element when present are of at least partially recycled origin. The expression "at least partially recycled" means that there is at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% recycled content in said product. element, said recycled composition itself comprising at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% of amide patterned copolyamide (Bal) and polyether patterned copolyamide (Ba2) of recycled origin. In one embodiment, where the monomaterial consists of three or more elements, said composition of the third element comprises at least one homopolyamide or at least one long-chain copolyamide. In another embodiment, where the single material consists of three or more elements, said composition of the third element (E3) comprises at least one copolyamide with amide motifs (Bal) and polyether motifs (Ba2). In yet another embodiment, where the monomaterial consists of three or more elements, said composition of the third element comprises a mixture of at least one homopolyamide or at least one long-chain copolyamide and at least one amide-motif (Bal) and polyether-motif (Ba2) copolyamide. In another embodiment, the composition of the first element (E1) comprises a single copolyamide with amide motifs (Bal) and polyether motifs (Ba2). In another embodiment, the composition of the second element (E2) comprises a single copolyamide with amide motifs (Bal) and polyether motifs (Ba2). In another embodiment, the composition of the third element (E3) if present comprises a single homopolyamide or at least one long-chain copolyamide. In another embodiment, the composition of the third element (E3) if present comprises a single copolyamide with amide motifs (Bal) and polyether motifs (Ba2). In another embodiment, the composition of the first element (El) comprises a single copolyamide with amide motifs (Bal) and polyether motifs (Ba2) and the composition of the second element (E2) comprises a single copolyamide with amide motifs (Bal) and polyether motifs (Ba2). In another embodiment, the composition of the first element (El) comprises a single copolyamide with amide motifs (Bal) and polyether motifs (Ba2) and the composition of the second element (E2) comprises a single copolyamide with amide motifs (Bal) and polyether motifs (Ba2) and the composition of the third element (E3) if present comprises a single homopolyamide or at least one long-chain copolyamide. In another embodiment, the composition of the first element (El) comprises a single copolyamide with amide motifs (Bal) and polyether motifs (Ba2) and the composition of the second element (E2) comprises a single copolyamide with amide motifs (Bal) and polyether motifs (Ba2) and the composition of the third element (E3) if present includes a single copolyamide with amide motifs (Bal) and po-1ether motifs (Ba2). In another aspect, the present invention relates to a method for manufacturing a single-material object as defined above, comprising the steps of: To provide a first element consisting of a first composition comprising by weight at least 30%, in particular at least 50%, particularly at least 70%, more particularly at least 90%, relative to the total weight of the first element of at least one amide-coupled (Bal) and polyether-coupled (Ba2) copolyamide, as defined above, Provide a second component consisting of a second composition comprising, by weight, at least 30%, in particular at least 50%, particularly at least 70%, more particularly at least 90%, relative to the total weight of the second component, of at least one amide-coupled (Bal) and polyether-coupled (Ba2) copolyamide, as defined above, Assemble the elements of the object using adhesive if necessary, to form the finished or semi-finished object. In one embodiment, the process defined above includes an additional step prior to assembly of supplying a third element consisting of a third composition comprising by weight at least 30%, in particular at least 50%, particularly at least 70%, more particularly at least 90%, relative to the total weight of the third element of at least one homopolyamide or at least one long-chain copolyamide, as defined above, or at least one amide motif (Bal) and polyether motif (Ba2) copolyamide or a mixture of the two. In the case of a semi-finished object, a step of adding other elements not recyclable by the process of the invention but preferably easily separable from the elements of the invention: for example the electronics of a watch, is carried out. According to yet another aspect, the present invention relates to a method for recycling an object as defined above, comprising the steps of: (a) supply of the used item, (b) optionally, separation of the elements of the object that are not recyclable in said process, (c) optionally cleaning the used item from step (a) or (b), (d) optionally first grinding of the used item from step (a) or (b), or from step (c) when the cleaning of step (c) is carried out in order to obtain a first grinding, (e) optionally washing the first ground material when the cleaning in step (c) is not carried out, (f) grinding the used item from step (a) and / or (b) and / or (c) and / or (d) and / or (e) in order to to obtain a first grind or a second grind in the case where a first grinding of step (d) has been carried out, (g) heating the ground material from step {f) until it melts, (h) optionally compounding and (i) extrusion or injection of the molten mass. The first and / or second grinding can take place before or after cleaning. The cleaning is carried out using compressed air, particularly under pressure, or using hot water or steam from said structure. Compressed air cleaning makes it possible to remove non-polymer particles such as soil, sand or dust from the used object. Cleaning with hot water or steam allows the water-soluble components of the used object to be dissolved and at least partially removed in order to obtain the other constituents of the used object. The temperature of the hot water or water vapor is between 70°C and 150°C, in particular between 70°C and 120°C. Hot water can have a pH between 1 and 12. The compounding step (h) allows the addition of a shock modifier and / or a filler and / or an additive and / or a plasticizer. If step (h) is carried out, then the material obtained after said step (h) is in the form of granules to be subsequently extruded or injected. The expression “used object” refers to an object that is no longer new, that has already been used or that has already been used, but in no way refers to a post-industrial object that would be recycled without having been used or that has not been used. In another embodiment, the present invention relates to a recycling process as defined above, further comprising the step of: (j) Addition of new material to the shredded used object before or after step (f) or after step (g). The term new material refers to both another polymer, in particular another polyamide, in particular a polyamide with a C / N < 8, and to fillers and additives. Regarding additives: The additive is optional and ranges from 0 to 20%, specifically from 0.1 to 5% by weight. The additive is chosen from colorants, stabilizers, plasticizers, surfactants, nucleating agents, pigments, brighteners, antioxidants, lubricants, flame retardants, natural waxes, shock modifiers, laser marking additives, and mixtures thereof. Regarding the charges: Regarding the fillers, these are reinforcing fibers, which are in particular fibers of mineral, organic or vegetable origin. The said reinforcing fiber may be coated or uncoated. The said reinforcing fiber can therefore include up to 0.1% by weight of a material of an organic nature (such as thermosetting resin or thermoplastic) called sizing. Examples of mineral-based fibers include carbon fibers, glass fibers, basalt fibers or basalt-based fibers, silica fibers, and silicon carbide fibers. Examples of organic-based fibers include thermoplastic or thermosetting polymer-based fibers, such as semi-aromatic polyamide fibers, aramid fibers, or polyolefin fibers. Preferably, these fibers are based on an amorphous thermoplastic polymer and have a glass transition temperature (Tg) higher than the Tg of the thermoplastic polymer or blend of polymers used in the pre-impregnation matrix when the latter is amorphous, or higher than the Tf of the thermoplastic polymer or blend of polymers used in the pre-impregnation matrix when the latter is semi-crystalline.Among the plant-based fibers, we can mention natural fibers made from flax, hemp, lignin, bamboo, silk (particularly spider silk), sisal, and other cellulosic fibers, especially viscose. These plant-based fibers can be used pure, treated, or coated with a layer of coating 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. Glass fibers can have a circular or non-circular cross-section. A fiber with a circular cross-section is defined as a fiber that has at every point of its circumference a distance equal to the center of the fiber and therefore represents a perfect or almost perfect circle. Any glass fiber that does not have this perfect or near-perfect circle is therefore defined as a fiber with a non-circular cross-section. Examples of non-circular cross-section fibers, but not limited to these, include non-circular fibers, such as elliptical, oval or cocoon-shaped fibers, star-shaped fibers, flake fibers, flat fibers, cruciform fibers, polygonal fibers and rings. Fiberglass can be: - either with a circular cross-section with a diameter between 4 µm and 25 µm, preferably from 4 to 15 µm. - either with a non-circular cross-section with an L / D ratio (L representing the largest dimension of the cross-section of the fiber and D the smallest dimension of the cross-section of said fiber) between 2 and 8, in particular between 2 and 4. L and D can be measured by scanning electron microscopy (SEM). Advantageously, glass fibers are circular. Glass fibers are notably of type E, R, S2, or T. Advantageously, glass fibers are of type E. In another embodiment, the charges are present from 0 to 65%. In one embodiment, the charges are recycled. For fillers containing glass, they can notably be manufactured from industrial production waste or post-consumer glass. Carbon fibers can, for example, be obtained from the cutting of spools of expired long fibers, particularly carbon fibers for the aerospace industry. Advantageously, the fillers are selected from glass fibers, particularly circular fibers, and carbon fibers, particularly glass fibers, especially circular fibers. In another aspect, the present invention relates to a recycled polyamide composition obtainable by the process as defined above. In yet another aspect, the present invention relates to a composition comprising, by weight: from 30 to 100%, advantageously from 50 to 99% recycled polyamide from the single-material objects defined above, from 0 to 70% virgin polyamides selected from homopolyamides, in particular long-chain polyamides, copolyamides, in particular long-chain polyamides and PEBA, in particular long-chain polyamides, advantageously the virgin polyamide is a PEBA, in particular long-chain polyamide, from 0 to 65% of charges, from 0 to 20%, in particular from 0.1 to 5% by weight of additives, the sum of the constituents being equal to 100%, said recycled polyamide having functional groups resulting from oxidation reactions selected from primary amides, nitriles, methyl groups at the end of the chain, alkenes, formamides, imides, carboxylic acids and alcohols and mixtures thereof, in a molar ratio to amides greater than that of the same polyamide constituting a non-used article that has never been used. The term PEBA is as defined above. Throughout this description, the term "long-chain PEBA" refers to a co-polyamide with amide (Bal) and polyether (Ba2) motifs as defined above, wherein the polyamide motifs are long-chain motifs with a C / N ratio greater than or equal to 8, more particularly greater than or equal to 9, notably greater than or equal to 10 When using a single-material object, new species arising from oxidation mechanisms, including amide functions and / or methylene alpha to said amide functions, such as imide functions, carboxylic acids, primary amides and alcohols appear in the polyamides constituting said tubes or reservoirs. These functions appear due to UV radiation or heat, or due to a reaction with a compound with which the object comes into contact. For example, gasoline, sunscreen, lubricants. These functions can be detected by infrared spectrometry or NMR. Thus, the absorption band from 1700 to 1740 cm-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 carboxylic acid. The absorption band from 3580 to 3670 eM-1 corresponds to the free alcohol function. The amide function is characterized on the one hand by a pair of absorption bands from 3100 to 3500 cm-1 and from 15560 to 1640 eM-1 which corresponds to the NH group of the amide and on the other hand by the absorption band from 1650 to 1700 cm-1 which corresponds to the carbonyl group of the amide. In a first variant, said composition comprises by weight: 50 to 70% recycled polyamide from the mono-material articles defined above, 30 to 50% virgin polyamides chosen from homopolyamides, in particular long-chain polyamides, copolyamides, in particular long-chain polyamides, and PEBA, in particular long-chain polyamides, advantageously the virgin polyamide is a PEBA, in particular long-chain polyamide, from 0 to 20%, in particular from 0.1 to 5% by weight of additives, the sum of the constituents being equal to 100%. In a second variant, the composition comprises, by weight: 30 to 50% recycled polyamide from the mono-material articles defined above, 0 to 65% virgin polyamides chosen from homopolyamides, in particular long-chain, copolyamides, in particular long-chain, and PEBA, in particular long-chain, advantageously the virgin polyamide is a PEBA, in particular long-chain from 5 to 60% in charges, from 0 to 20%, in particular from 0.1 to 5% by weight of additives, the sum of the constituents being equal to 100%. In a third variant, said composition comprises by weight: 60 to 80% recycled polyamide from the mono-material articles defined above, 0 to 20% virgin polyamides selected from homopolyamides, in particular long-chain, copolyamides, in particular long-chain, and PEBA, in particular long-chain, advantageously the virgin polyamide is a PEBA, in particular long-chain, 20 to 40% in charges, from 0 to 20%, in particular from 0.1 to 5% by weight of additives, the sum of the constituents being equal to 100%. In a fourth variant, said composition comprises by weight: 40 to 60% recycled polyamide from the mono-material articles defined above, 0 to 20% virgin polyamides selected from homopolyamides, in particular long-chain, copolyamides, in particular long-chain, and PEBA, in particular long-chain, advantageously the virgin polyamide is a PEBA, in particular long-chain, 40 to 60% of charges, from 0 to 20%, in particular from 0.1 to 5% by weight of additives, the sum of the constituents being equal to 100%. In one embodiment, in said compositions of this other aspect and its four variants, the term "includes" is replaced by the term "consisting of". The compositions of these four variants and their embodiments are compositions particularly suited to the embodiment in which the single-material object defined above is characterized in that only one of the two compositions includes a filler, the other being devoid of one. In one embodiment, said molar ratio of functions resulting from oxidation reactions relative to secondary amide functions is between 1 / 10000 and 1 / 20. Concentrations can be measured by proton NMR in d2-dichloromethane, by adding HFIP (hexafluoroisopropanol) to solubilize the polyamide. In a first variant, the said molar ratio of the imide functions is between 1 / 1000 and 1 / 20, in particular between 1 / 500 and 1 / 20, in particular between 1 / 200 and 1 / 50. In a second variant, the said molar ratio of the carboxylic acid functions is between 1 / 5000 and 1 / 20, in particular between 1 / 3000 and 1 / 50, very advantageously between 1 / 500 and 1 / 15. In a third variant, the molar ratio of the alcohol functions is between 1 / 1000 and 1 / 20, and advantageously between 1 / 1000 and 1 / 25, very advantageously ranging from 1 / 200 to 1 / 50. In a fourth variant, the said molar ratio of primary amide functions to secondary amide functions is between 1 / 2000 and 1 / 20 and advantageously between 1 / 1000 and 1 / 100 very advantageously between 1 / 1000 and 1 / 500. In a fifth variant, the said molar ratio of nitrile functions to secondary amide functions is between 1 / 1000 and 1 / 20 and advantageously between 1 / 500 and 1 / 15 very advantageously between 1 / 100 and 1 / 10. In a fifth variant, the molar ratio of methyl functions at the end of the chain relative to secondary amide functions is between 1 / 5000 and 1 / 50 and advantageously between 1 / 2000 and 1 / 100, very advantageously between 1 / 1000 and 1 / 200. It is quite clear that depending on the single-material objects used and the exposure to which they have been subjected, one or more functions resulting from oxidation reactions may be present. The composition also advantageously includes residues of stabilizers selected from phenols, quinones, stylbenequinone and phosphite. Recycled polyamide advantageously contains alkyl chain ends with a higher carbon number (between 1 and 18) than virgin PA. Advantageously, the alkyl chain end content is between 1 ppm and 0.5%. According to another aspect, the present invention relates to the use of a composition as defined above for the manufacture of objects, in particular mono-material objects. The said single-material object thus manufactured from a used single-material object can itself be recycled according to the process of the invention at least once, in particular from 1 to 10 times. EXAMPLES The following examples illustrate the invention without limiting it. The ECI and El1 shin guards were assembled by overmolding. The percentages indicated are mass percentages. The following polymers were used to manufacture the parts: - PEBA n°1: PEBA copolymer comprising PA 11 blocks with a number average molar mass of 1000 g / mol and flexible PTMG blocks with a number average molar mass of 1000 g / mol and a hardness of 40 Shore D. - PEBA n°2: PEBA copolymer comprising PA 11 blocks with a number average molar mass of 600 g / mol and flexible PTMG blocks with a number average molar mass of 1000 g / mol and a hardness of 35 Shore D. - TPU No. 1: Rigid block TPU based on 4,4'-MDI (4,4-diphenylmethylene diisocyanate) and 1,4-BDO (1,4-butanediol) and flexible polyester block TPU based on acid adipic and butane diol, with a hardness of 85 Shore A. The ECI and EI 1 objects were ground into a granulate with a size of less than 30 mm and then compounded in an 18 mm twin-screw extruder at a flow rate of Skg / h and a temperature of 230 °C in order to obtain granules to evaluate the properties obtained during the second life of the material. The compositions were then dried under reduced pressure at 80°C in order to achieve a moisture content of less than 0.04%. 2 mm thick plates were manufactured by injection molding using a Battenfeld BA800 CDC press with unpolished molds. The following parameters were applied during injection: - Sheath temperature: 180°C. - Nozzle temperature: 200°C. - Mold temperature: 30°C. - Cycle time: 60 seconds. The density at 23 °C was measured according to ISO 1183-1 on 2 mm plates. The tan Δ at 23 °C was measured according to ISO 6721 (2019), at a tensile strain of 0.1%, a frequency of 1 Hz, and a heating rate of 2 °C / min. All these evaluations were performed on dry specimens. (unconditioned). The compositions and their evaluation are presented in Table 1. [Table 1] Shin guard Er 1 |EC1 Element 1: Inner layer Element 2: Outer layer ; |PEBA2 |TPU1 50% 50%, |PEBA1 |PEBA1 50% 50% Density (ISO1183-1) 1.024 1.064 Tan delta at 23 °C 0.03 0.09 It is observed that the composition according to the invention has a lower tan at 23°C than that of the comparative compositions, and therefore has a higher elastic return, while maintaining a lower density than that of the comparative composition. The objects of the invention can therefore be recycled to manufacture high-performance parts. formance.

Claims

Claims

1. Single-material object comprising at least two elements: - at least a first element consisting of a first composition comprising by weight at least 30%, in particular at least 50%, partic- particularly at least 70%, more particularly at least 90%, by relative to the total weight of the first element, of a patterned copolyamide amides (Bal) and polyether units (Ba2) - at least one second element consisting of a second composition comprising by weight at least 30%, in particular at least 50%, partic- particularly at least 70%, more particularly at least 90%, by relative to the total weight of the second element, of a patterned copolyamide amides (Bal) and polyether units (Ba2) said first and second elements being able to adhere at least par- closely to each other, said copolyamide of the first composition and said copolyamide of the second composition with a higher C / N ratio of the pattern (Bal) or equal to 6, in particular greater than or equal to 8, in particular greater than or equal to 9, in particular greater than or equal to 10.

2. Single-material object according to claim 1, characterized in that it is chosen from an electronic article, a textile article, an optical article, a household appliance, a cosmetic item, a sports item, a stationery item, luggage item, toy, furniture and auto parts.

3. Single-material object according to claim 1 or 2, characterized in that that only one of the two compositions includes a charge, the other in being deprived.

4. Single-material object according to claim 1 to 3, characterized in that at least 10% by weight of the patterns, in particular at least 30% by weight, constituting said at least one patterned polyamide (Bal) of the first composition and said patterned polyamide (Bal) of the second composition are identical, in particular said patterns are patterns PAII.

5. Single-material object according to claim 1 to 4, characterized in that the first composition and the second composition comprise the same polyamide motif, in particular a PAI1I.

6. Single-material object according to one of claims | to 4, characterized in that said first and second elements are chosen from among the following constituents: a textile, a film or textured film, a foam, an injected part, an extruded part, a 3D printed part, a adhesive, a non-woven fabric, a veil and a thermo-composite part consolidated plastic.

7. Single-material object according to claim 6, characterized in that it comprises at least two constituents defined in claim 6 and which are different.

8. Single-material object according to claim 7, characterized in that it comprises at least three constituents defined in the resale- dication 6, in particular different.

9. Single-material object according to one of claims | to 8, characterized in that the first and second elements adhere to each other by bonding using a non-polyamide adhesive in a content of from 0.01% to 10% by weight, in particular from 0.1% to 4% by weight per relative to the total mass of the object.

10. Single-material object according to one of claims 1 to 9, characterized in that it includes at least a third element consisting of a third composition including at least one homopolyamide or at least one long-chain copolyamide chain or at least one copolyamide with amide units (Bal) and units polyethers (Ba2) or a mixture thereof, said at least one co- polyamide with amide units (Ba!) and polyether units (Ba2) being such as defined in claim 1.

11. Method of manufacturing a single-material object according to one of the claims- indications 1 to 10, comprising the steps of: Provide a first element consisting of a first composition comprising by weight at least 30%, in particular at least 50%, partic- particularly at least 70%, more particularly at least 90%, by relative to the total weight of the first element of at least one copolyamide to amide units (Bal) and polyether units (Ba2), as defined in one of claims 1 to 10, Provide a second element consisting of a second composition comprising by weight at least 30%, in particular at least 50%, partic- particularly at least 70%, more particularly at least 90%, by relative to the total weight of the second element, of at least one copolyamide with amide units (Bal) and with polyether units (Ba2), as defined in one of claims 1 to 10, Assemble the elements of the object using an adhesive if necessary, to form the finished or semi-finished object.

12. A method of recycling the object as defined in one of the claims- indications 1 to 10, comprising the steps of: (a) supply of the used item, {b) optionally separation of elements of the object which are not recyclable in said process, {c) optionally cleaning the used object from step (a) or (b), {d) optionally first crushing of the used object from step (a) or {b), or step (c) when the cleaning of step (c) is carried out in order to obtain a first crush, {e) optionally washing of the first shredded material when cleaning step (c) is not performed, ({) crushing of the used object from step (a) and / or (b) and / or (c) and / or (d) and / or (e) in order to obtain a first grind or a second grind in the case where a first grinding of step (d) has been carried out, (g) heating the ground material from step (f) until it melts, (h) optionally compounding and {i) extrusion or injection of the molten mass.

13. A recycling method according to claim 12, further comprising the step of: (j) Addition of new material to the ground material of the used object before or after step (f) or after step (g).

14. Recycled polyamide composition obtainable by the method according to claims 12 to 13.

15. Composition comprising by weight from 30 to 100%, advantageously from 50 to 99% recycled polyamide from the single-material objects defined above, from 0 to 70% of virgin polyamides chosen from homopolyamides, in particular long chain, copolyamides, in particular long chain and PEBA, advantageously the virgin polyamide is a PEBA from 0 to 65% load, from 0 to 20%, in particular from 0.1 to 5% by weight of additives, the sum of the constituents being equal to 100%, said recycled polyamide having functions resulting from reactions oxidation chosen from primary amide, nitrile, methyl groups at the end of the chain, alkenes, formamides, imides, carboxylic acids and alcohols and their mixtures, in a molar ratio compared to amide functions higher than that of the same polyamide constituting an unused object that has never been used before.

16. Composition according to claim 15, characterized in that said ratio molar of functions resulting from oxidation reactions compared to secondary amide functions is from 1 / 10000 to 1 / 20.

17. | Composition according to claim 15 to 16, characterized in that said molar ratio of imide functions to amide functions se- secondary is understood from 1 / 1000 to 1 / 20, in particular from 1 / 500 to 1 / 20, in particular from 1 / 200 to 1 / 50.

18. Composition according to one of claims 15 to 17, characterized in that that said molar ratio of carboxylic acid functions relative to to secondary amide functions is between 1 / 5000 and 1 / 20, in particular from 1 / 3000 to 1 / 50 very advantageously included from 1 / 500 to 1 / 15.

19. Composition according to one of claims 15 to 18, characterized in that that the said molar ratio of alcohol functions compared to the functions secondary amides is between 1 / 1000 and 1 / 20 and advantageously included from 1 / 1000 to 1 / 25 very advantageously included from 1 / 200 to 1 / 50.

20. Composition according to one of claims 15 to 19, characterized in that that said molar ratio of primary amide functions compared to secondary amide functions is included from 1 / 2000 to 1 / 20 and advantageously- generously understood from 1 / 1000 to 1 / 100 very advantageously understood from 1 / 1000 to 1 / 500.

21. Composition according to one of claims 15 to 20, characterized in that that said molar ratio of nitrile functions relative to the functions secondary amides is between 1 / 1000 and 1 / 20 and advantageously included from 1 / 500 to 1 / 15 very advantageously included from 1 / 100 to 1 / 10.

22. Composition according to one of claims 15 to 21, characterized in that that the said molar ratio of methyl functions at the end of the chain by ratio to secondary amide functions is between 1 / 5000 and 1 / 50 and advantageously included from 1 / 2000 to 1 / 100 very advantageously from 1 / 1000 to 1 / 200.

23. Use of the composition according to one of claims 14 to 22, for the manufacture of objects, particularly single-material ones.