Recyclable single material object comprising at least two elements

Abstract

The invention relates to a single-material object comprising at least two elements:-at least one first element consisting of a first composition comprising at least 30% by weight, relative to the first total weight of the elements, of at least one homopolyamide or at least one long-chain copolyamide, at least one first element consisting of a first composition excluding a copolyamide having amide units (Ba1) and polyether units (Ba2),-at least one second element consisting of a second composition comprising at least 30% by weight of a copolyamide having amide units (Ba1) and polyether units (Ba2), the first and second elements being capable of at least partially adhering to each other, relative to the total weight of the second element, and-at least one second element consisting of a second composition comprising at least 30% by weight of a copolyamide having amide units (Ba1) and polyether units (Ba2), the at least one homopolyamide or the at least one long-chain copolyamide of the first composition has a C / N ratio of 8 or greater, and the copolyamide of the second composition has a C / N ratio of units (Ba1) of 6 or greater, in particular 8 or greater, where the object should not comprise a single-layer or multi-layer structure for transporting, dispensing or storing fluids.

Description

Technical Field

[0001] This patent application relates to recyclable single-material objects comprising at least two (two) elements, to their manufacturing method and their recycling method, to the compositions obtained thereby, and to their use in the manufacture of objects, in particular single-material objects. Background Art

[0002] Through the circular economy, waste generation, consumption of the planet's resources, and environmental impacts can be restricted. Currently, particular attention is paid to producing objects from materials that, after recycling, will have properties sufficient to enable them to be used in high-performance applications rather than only in lower-performance applications such as for street furniture or roads.

[0003] In the context of sustainable consumption and production patterns, the recyclability of frequently renewed items, such as sports equipment and E&E products, and the quality of the recycled products obtained therefrom are particularly important. However, the performance requirements for these items are particularly high.

[0004] Objects (sports equipment and E&E products) must be designed in such a way that they can be recycled into very high-performance materials. Equally important is that the products used to manufacture the objects are stable enough to be recycled safely. When thermoplastic polyurethane (TPU) is recycled, the formation of isocyanates can be observed by FTIR. Isocyanates are dangerous CMR compounds.

[0005] To facilitate its recycling, patent EP 3 081 109 B1 proposes a sports shoe in which the upper part and the sole are mainly or even entirely formed of the same thermoplastic base material. However, since the density of the components of the shoe varies according to their respective functions, difficulties still seem to exist and the recycled products obtained in this way have limitations in terms of performance.

[0006] Patent application WO 2020 / 201370A1 proposes a method for recycling such shoes, in which the shoes are ground and then melted. As with the previous one, the document focuses on thermoplastic polyurethane (TPU). The international patent application points out the fact that TPU degrades with the recycling cycles.

[0007] Patent application US 2017 / 0151470 A1 relates to a ball, in particular a football, and to a method for manufacturing and recycling the ball. The ball includes a bladder, an intermediate layer, and an outer layer, and the bladder and the two layers are composed of the main component by weight of a material selected from a first material class of polyurethane, polyvinyl chloride, polyethylene, polyamide, and polypropylene.

[0008] The international patent application WO 2021 / 148148 A1 relates to a lined garment product comprising an outer layer, an inner layer and a lining between the two layers.

[0009] Each layer contains a major amount of materials from the same class, which are selected from thermoplastic polymers, in particular recycled polyesters or virgin polymers selected from thermoplastic polyurethanes (TPU), polyamides (PA), polyethylene terephthalate (PET) or polybutylene terephthalate (PBT). Polyester has the disadvantage of being very sensitive to hydrolysis.

[0010] Accordingly, an object of the invention is to provide a single-material object whose composition is studied so that a composition can be obtained for applications requiring high performance upon recycling.

[0011] Now it has been shown that an exclusive combination (excluding additives and fillers) in a single-material object of polyamide fraction and polyether block amide (PEBA) fraction provides better maintenance of properties during recycling.

[0012] Specifically, the presence of polyamide in the composition notably provides good tolerance to aging and thus the lifespan of the object and its recycling method. For its part, the presence of the more flexible PEBA helps to improve the mechanical strength of the object throughout its life cycle, before and after recycling.

[0013] Accordingly, in a first aspect, a subject of the invention is a single-material object comprising at least two elements:

[0014] - at least one first element consisting of a first composition, the first composition comprising at least 30% by weight, notably at least 50% by weight, particularly at least 70% by weight, more particularly at least 90% by weight of at least one long-chain homopolyamide or at least one long-chain copolyamide, relative to the total weight of the first element,

[0015] The at least one long-chain homopolyamide and the at least one copolyamide independently of one another represent repeating units selected from: units obtained by the polycondensation of at least one C4-C36 amino acid, units obtained by the polycondensation of at least one C4-C36 lactam, and XY units obtained by the polycondensation of:

[0016] - at least one diamine selected from linear or branched aliphatic diamines, cycloaliphatic diamines and semi-aromatic aliphatic diamines, or mixtures thereof, and

[0017] at least one dicarboxylic acid selected from:

[0018] aliphatic dicarboxylic acids, cycloaliphatic dicarboxylic acids and aromatic dicarboxylic acids,

[0019] The diamine and the diacid contain from 4 to 36 carbon atoms, advantageously from 6 to 18 carbon atoms,

[0020] The first composition excludes copolyamides with amide units (Ba1) and polyether units (Ba2),

[0021] - at least one second element consisting of a second composition, the second composition containing at least 30% by weight, notably at least 50%, particularly at least 70%, more particularly at least 90% of a copolyamide with amide units (Ba1) and polyether units (Ba2), relative to the total weight of the second element,

[0022] The first and the second element can adhere to each other at least partially,

[0023] The at least one long-chain homopolyamide or at least one long-chain copolyamide of the first composition has a C / N ratio greater than or equal to 8, particularly greater than or equal to 9, notably greater than or equal to 10, and the copolyamide of the second composition has a C / N ratio of amide units (Ba1) greater than or equal to 6, notably greater than or equal to 8, particularly greater than or equal to 9, notably greater than or equal to 10,

[0024] The object excludes single-layer or multi-layer structures for transporting, distributing or storing fluids.

[0025] Thus, the inventors unexpectedly found that the exclusive combination (excluding additives) in a single-material object of a specific polyamide fraction (or element) (i.e., long-chain polyamide) and a specific polyether block amide (PEBA) copolyamide fraction (or element), i.e., a PEBA with a C / N ratio of amide units (Ba1) greater than or equal to 6, notably greater than or equal to 8, particularly greater than or equal to 9, notably greater than or equal to 10, allows for better maintenance of properties during recycling.

[0026] Specifically, the long-chain polyamide in one of the two compositions and the copolyamide with specific polyether block amide (PEBA) units in the other composition provide the best compromise, and notably provide good aging resistance and thus the lifespan of the object and the recycling method. They can moreover be recycled safely.

[0027] Thus, the recycled composition has the following advantages: low density, good elastic recovery, good fatigue strength, good impact strength, good mechanical tensile properties, good dimensional stability, and a stable modulus between -20°C and 30°C, as well as good chemical resistance, particularly good hydrolysis resistance.

[0028] The C / N ratio corresponds to the number of carbon atoms per nitrogen atom in the polyamide or copolyamide.

[0029] The term "single-material object" should be understood to mean an object mainly composed of the same material, in this case a long-chain polyamide in one of two compositions and a copolyamide with amide units (Ba1) and with polyether units (Ba2) in the other composition, which has a C / N ratio of units (Ba1) greater than or equal to 6, notably greater than or equal to 8, in particular greater than or equal to 9, notably greater than or equal to 10.

[0030] More precisely, the term "single-material object" should be understood to mean an object comprising at least two elements, each element being composed of a composition respectively containing at least one polymer matrix, wherein said polymer matrix mainly comprises, i.e. relative to its total weight greater than 50% by weight, respectively a long-chain homopolyamide or copolyamide as defined according to the invention, or a copolyamide with amide units (Ba1) and with polyether units (Ba2) as defined according to the invention.

[0031] For the purposes of the present invention, a single-material object can in particular be an object comprising at least two elements, each element being single-material, i.e. each element mainly composed of the same material as defined according to the invention.

[0032] The term "polymer matrix" is intended to denote the part of the composition consisting only of polymers, i.e. non-polymeric fillers and additives are excluded here.

[0033] Preferably, the polymer matrix respectively comprises at least 60% by weight, preferably at least 80% by weight, preferably at least 90% by weight, advantageously at least 95% by weight, or even 100% by weight of a long-chain homopolyamide or copolyamide as defined according to the invention, or a copolyamide with amide units (Ba1) and polyether units (Ba2) as defined according to the invention.

[0034] According to one embodiment, a "single-material object" for the purposes of the present invention is an object comprising at least two elements, each element being mainly composed of, i.e. relative to its total weight greater than 50% by weight, respectively a long-chain homopolyamide or copolyamide as defined according to the invention, or a copolyamide with amide units (Ba1) and polyether units (Ba2) as defined according to the invention.

[0035] Preferably, each element is composed of a composition comprising at least 80% by weight, preferably at least 90% by weight, advantageously at least 95% by weight, or even 100% by weight of, respectively, a long-chain homopolyamide or copolyamide as defined according to the invention, or a copolyamide with amide units (Ba1) and polyether units (Ba2) as defined according to the invention.

[0036] According to one embodiment, the single-material object of the present invention is an object comprising at least two elements, each element being composed of a composition comprising less than 20% by weight, preferably less than 10% by weight, such as less than 5% by weight, such as less than 3% by weight, in particular 0% by weight, of short-chain polyamide, i.e. a polyamide having a C / N ratio of strictly less than 8, notably less than or equal to 7, in particular less than or equal to 6, relative to its total weight.

[0037] According to one embodiment, the single-material object of the present invention comprises less than 20% by weight, preferably less than 10% by weight, such as less than 5% by weight, such as less than 3% by weight, in particular 0% by weight, of short-chain polyamide, i.e. a polyamide having a C / N ratio of strictly less than 8, notably less than or equal to 7, in particular less than or equal to 6, relative to its total weight.

[0038] In a first variant, the single-material object can be, but is not limited to, the following:

[0039] Electronic articles, in particular watches, telephone housings, headsets, headphones, speakers, keyboards, mice, telephone chargers, preferably telephone housings, headsets, headphones, speakers, keyboards, mice, telephone chargers,

[0040] Clothing articles, in particular jackets, trousers, T-shirts or socks,

[0041] Optical articles, in particular prescription glasses, sunglasses, children's glasses, sports glasses and ski masks, augmented reality / virtual reality goggles,

[0042] Household electrical articles, in particular small household appliances, accessories for household electrical articles (bowls, mixing paddles, food containers), flasks, food containers

[0043] Cosmetic articles, in particular cosmetic packaging such as bottles, perfumes, cosmetic packaging, skin care packaging, display articles, hairbrushes,

[0044] Sports articles, in particular surfboards (and their accessories, such as straps or fins), bicycles, bicycle articles such as saddles or pedals, helmets, ski boots, skis, ski poles, ski bindings and snowboards (excluding metal), golf clubs, any type of racket, in particular tennis rackets, protective equipment such as shin guards, elbow pads, etc., hockey crosses (on grass or ice), roller skates, diving fins,

[0045] Luggage articles, in particular suitcases, travel bags and handbags,

[0046] Stationery articles, in particular pens,

[0047] Toys,

[0048] Furniture, and

[0049] motor vehicle parts,

[0050] (excluding single - layer or multi - layer structures for transporting, distributing, or storing fluids).

[0051] The statement "the object excludes single - layer or multi - layer structures for transporting, distributing, or storing fluids" means excluding single - layer or multi - layer structures for transporting, distributing, or storing fluids from the object, especially for those with thermal or electric motor equipment, such as airplanes, drones, aircraft, trucks, or motor vehicles.

[0052] In one embodiment of this first variant, the single - material object corresponds to all those described in the list of this first variant, except for at least one of those described in the same list, and excludes single - layer or multi - layer structures for transporting, distributing, or storing fluids.

[0053] Needless to say, at least the single - material object corresponds to at least one of those described in the list of this first variant.

[0054] In the second variant, the single - material object can be an electronic product, a textile product, an optical product, a household electrical product, a cosmetic product, a sports product, a stationery product, a luggage product, a toy, furniture, and motor vehicle parts (excluding single - layer or multi - layer structures for transporting, distributing, or storing fluids).

[0055] In one embodiment of this second variant, the single - material object corresponds to all those described in the list of this second variant, except for at least one of those described in the same list, and excludes single - layer or multi - layer structures for transporting, distributing, or storing fluids.

[0056] Needless to say, at least the single - material object corresponds to at least one of those described in the list of this second variant.

[0057] In the third variant, the single - material object can be an electronic product, a textile product, an optical product, a household electrical product, a cosmetic product, a sports product, a stationery product, a luggage product, a toy, or furniture.

[0058] In one embodiment of this third variant, the single - material object corresponds to all those described in the list of this third variant, except for at least one of those described in the same list, and excludes single - layer or multi - layer structures for transporting, distributing, or storing fluids.

[0059] Needless to say, at least the single - material object corresponds to at least one of those described in the list of this third variant.

[0060] The object is excluded from single - layer or multi - layer structures for transporting, distributing or storing fluids.

[0061] The term "fluid" encompasses any gas in compressed form, liquid form or cryogenic compression, and in particular hydrogen, natural gas, LPG, LNG, compressed air, nitrogen, oxygen, and heat - transfer fluids, in particular refrigerants selected from the following compounds: hydrocarbons, hydrofluorocarbons, ethers, hydrofluoroethers, CO2, NH3, SO2 and fluoroolefins, in particular R134, R - 1234yf or R - 1234ze, in particular R - 1234yf or R - 1234ze, or gases used in motor vehicles, in particular air, or liquids used in motor vehicles, in particular water, oil, brake fluid, urea solution, glycol - based coolant, transmission oil coolant (TOC), fuel, in particular diesel, gasoline, more particularly gasoline - alcohol blend or LPG.

[0062] In one embodiment, shoes, balls, jackets, seats, especially vehicle seats, toothbrushes or travel bags are excluded from the single - material objects of the present invention.

[0063] Preferably, the present invention relates to single - material objects obtainable by injection molding.

[0064] According to one embodiment, the single - material object of the present invention is different from multi - layer structures comprising a fabric layer, a film and optionally a hot - melt adhesive composition between the fabric layer and the film.

[0065] According to one embodiment, the single - material object of the present invention is different from multi - layer structures comprising (i) a fabric layer comprising at least one polymer selected from polyamides and copolymers comprising polyamide blocks and polyether blocks and combinations thereof, and (ii) a film comprising at least one copolymer comprising polyamide blocks and polyether blocks, the polyether block comprising a polyethylene glycol block, the polyethylene glycol block accounting for at least 40% by mass relative to the mass of the film, wherein the film is adhered to the fabric layer by a copolyamide.

[0066] According to one embodiment, the single - material object of the present invention is different from multi - layer structures comprising (i) a film composed of PA11 / PEG6 (40 / 60 by weight), where Mn(PA11) is equal to 1000 g / mol and Mn(PEG) is equal to 1500 g / mol and Tm is equal to 150 °C, and (ii) a film composed of PA6 / 6.12 / 11 / PEG12 (24.5 / 20.9 / 24.5 / 30.1 by weight respectively), where Mn(PA) is equal to 2000 g / mol and Mn(PEG) is equal to 600 g / mol and Tm is equal to 100 °C.

[0067] According to one embodiment, the single-material object of the present invention is different from bandages, gauzes, fabrics, carpets, rugs, upholstery coverings, surface coverings, passenger compartment coverings, sofas, curtains, bedding, mattresses, pillows, clothing, especially sports clothing or medical clothing.

[0068] According to one embodiment, the single-material object of the present invention is different from soles, especially different from the soles of sports shoes.

[0069] In one embodiment, at least 50% by weight of a long-chain polyamide or long-chain copolyamide and a polyamide with amide units (Ba1) in the copolyamide are present in each of the two elements, relative to the total weight of the composition of each element.

[0070] In other words, the total weight of the long-chain polyamide or long-chain copolyamide in the first element and the polyamide with amide units (Ba1) in the second element is at least 50%, based on the total weight of the two compositions of the respective elements.

[0071] 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 the long-chain polyamide or long-chain copolyamide of the first element or the polyamide with amide units (Ba1) of the second element.

[0072] The term "element" means each of the following things that combine to form another thing, the whole, i.e., the single-material object in the present invention.

[0073] In particular, an element means a component, constituent, fragment, part (component), sheet or unit that constitutes a single-material object.

[0074] The statement "the first and second elements may be at least partially adhered to each other" means that the first and second elements may or may not be adhered to each other.

[0075] In one embodiment, the first and second elements are not adhered to each other.

[0076] In another embodiment, the first and second elements are at least partially, especially completely, adhered to each other.

[0077] The term "adhered" means that the first and second elements are placed or applied against each other at least partially and especially by adhesion, snap-fastening, overmolding, thermoforming, screwing, stitching, welding or riveting.

[0078] Needless to say, the first composition comprising the long-chain homopolyamide and copolyamide may also contain an impact modifier and / or a plasticizer and / or a filler and / or an additive.

[0079] Needless to say, the second composition containing the copolyamide with an amide unit (Ba1) and a polyether unit (Ba2) may also contain an impact modifier and / or a plasticizer and / or a filler and / or an additive.

[0080] Needless to say, the third composition described below may contain a long-chain homopolyamide and a long-chain copolyamide or a copolyamide with an amide unit (Ba1) and a polyether unit (Ba2) or a mixture of both, and may also contain an impact modifier and / or a plasticizer and / or a filler and / or an additive.

[0081] Long-chain homopolyamides and copolyamides regarding the composition (the composition) of the first element and the third element.

[0082] The nomenclature used to define polyamides is described in the standard ISO 1874-1:2011 "Plastics - Polyamide (PA) molding and extrusion materials - Part 1: Designation", in particular on page 3 (Tables 1 and 2), and is well known to those skilled in the art.

[0083] The long-chain homopolyamides and copolyamides are polyamides having a C / N ratio (i.e., the average number of carbon atoms per nitrogen atom) greater than or equal to 8, particularly greater than or equal to 9, notably greater than or equal to 10.

[0084] In a first variant of the invention, the repeating unit is a unit obtained by the polycondensation of at least one C4-C 36 amino acid (or aminocarboxylic acid).

[0085] Advantageously, the aminocarboxylic acid contains 9 to 12 carbon atoms. Thus, it may be selected from 9-aminononanoic acid (denoted as 9), 10-aminodecanoic acid (denoted as 10), 11-aminoundecanoic acid (denoted as 11), and 12-aminododecanoic acid (denoted as 12); advantageously, the aminocarboxylic acid is 11-aminoundecanoic acid.

[0086] In a second variant of the invention, the repeating unit is a unit obtained by the polycondensation of at least one C4-C36 lactam.

[0087] Advantageously, the lactam contains 9 to 12 carbon atoms. Thus, it may be selected from caprolactam (denoted as 10), undecanolactam (denoted as 11), and laurolactam or lauryl lactam (denoted as 12); advantageously, the lactam is lauryl lactam.

[0088] However, it is perfectly conceivable to use a mixture of two or more amino carboxylic acids, a mixture of two or more lactams, and also a mixture of one, two or more amino carboxylic acids with one, two or more lactams.

[0089] More particularly preferably, the repeating unit is obtained from a single amino carboxylic acid or a single lactam.

[0090] Repeating unit XY

[0091] The repeating unit XY is obtained by polycondensation of units of at least one diamine and at least one dicarboxylic acid,

[0092] wherein the diamine is selected from linear or branched aliphatic diamines, cycloaliphatic diamines and semi-aromatic aliphatic diamines or mixtures thereof, and

[0093] at least one dicarboxylic acid, said diacid being selected from:

[0094] aliphatic diacids, cycloaliphatic diacids and aromatic diacids or mixtures thereof,

[0095] The molar ratio of diamine to dicarboxylic acid is preferably stoichiometric.

[0096] The diamine contains 4 to 36 carbon atoms, advantageously 6 to 18 carbon atoms.

[0097] According to one embodiment, the diamine contains 6 to 12 carbon atoms.

[0098] In the case where the diamine used to prepare the repeating unit XY is an aliphatic diamine having a linear backbone, the linear backbone may, where appropriate, include one or more methyl and / or ethyl substituents; in the latter configuration, it is referred to as a "branched aliphatic diamine". In the case where the backbone does not include any substituents, the aliphatic diamine is referred to as a "linear aliphatic diamine".

[0099] Regardless of whether it includes methyl and / or ethyl substituents on the backbone, the aliphatic diamine used to obtain the repeating unit XY contains 4 to 36 carbon atoms, advantageously 6 to 18 carbon atoms, notably 9 to 18 carbon atoms.

[0100] When the diamine is a linear aliphatic diamine, it corresponds to the formula H2N-(CH2)x-NH2 and may be selected, for example, from butanediamine, pentanediamine, hexanediamine, heptanediamine, octanediamine, nonanediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, hexadecanediamine, octadecanediamine and octadecenediamine. The straight-chain aliphatic diamines just mentioned can all be bio-based within the meaning of standard ASTM D6866.

[0101] When this diamine is a branched aliphatic diamine, it may in particular be 2-methylpentanediamine, 2-methyl-1,8-octanediamine or (2,2,4- or 2,4,4-)trimethylhexanediamine.

[0102] The cycloaliphatic diamines may be selected, for example, from bis(3,5-dialkyl-4-aminocyclohexyl)methane, bis(3,5-dialkyl-4-aminocyclohexyl)ethane, bis(3,5-dialkyl-4-aminocyclohexyl)propane, bis(3,5-dialkyl-4-aminocyclohexyl)butane, bis(3,5-dialkyl-4-aminocyclohexyl)methane or 3'-dimethyl-4,4'-diaminodicyclohexylmethane, commonly known as "BMACM" or "MACM" (and denoted hereinafter as B), p-bis(aminocyclohexyl)methane, commonly known as "PACM" (and denoted hereinafter as P), isopropylidene bis(cyclohexylamine), commonly known as "PACP", isophoronediamine (denoted hereinafter as IPD) and 2,6-bis(aminomethyl)norbornane, commonly known as "BAMN", or bis(aminomethyl)norbornane, commonly known as "BAC", or bis(aminomethyl)cyclohexane, commonly known as "BAC".

[0103] A non-exhaustive list of these cycloaliphatic diamines is given in the publication "Cycloaliphatic Amines" (Encyclopedia of Chemical Technology, Kirk-Othmer, 4th Edition (1992), pages 386-405).

[0104] When the diamine is a semi-aromatic aliphatic diamine, it is selected, for example, from 1,3-benzenedimethanamine and 1,4-benzenedimethanamine.

[0105] The dicarboxylic acid contains from 4 to 36 carbon atoms, advantageously from 6 to 18 carbon atoms and notably from 6 to 12 carbon atoms.

[0106] When the dicarboxylic acid is aliphatic, it may be selected from straight-chain or branched aliphatic dicarboxylic acids.

[0107] When the dicarboxylic acid is aliphatic and straight-chain, it may be selected from succinic acid (4), glutaric acid (5), adipic acid (6), pimelic acid (7), suberic acid (8), azelaic acid (9), sebacic acid (10), undecanedioic acid (11), dodecanedioic acid (12), tridecanedioic 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 carbon atoms.

[0108] The above fatty acid dimers are dimeric fatty acids obtained by oligomerization or polymerization of unsaturated monocarboxylic acids having long hydrocarbon chains, such as linoleic acid and oleic acid, as notably described in EP 0 471 566.

[0109] When the dicarboxylic acid is aromatic, it may be selected from terephthalic acid (denoted as T), isophthalic acid (denoted as I) and naphthalenedicarboxylic acid (denoted as N).

[0110] In one embodiment, the composition of the first element consists of a single homopolyamide.

[0111] In another embodiment, the homopolyamide of the composition of the first element is an aliphatic semi-crystalline homopolyamide.

[0112] For the purposes of the invention, the term "semi-crystalline homopolyamide" refers to a material which is usually solid at room temperature and softens during temperature increase, in particular after passing through its glass transition temperature (Tg), and which can melt sharply when passing through its "melting temperature" (Tm), and which becomes solid again when the temperature is lowered below its crystallization temperature.

[0113] For the purposes of the invention, the semi-crystalline homopolyamide has a melting temperature (Tm) according to standard ISO 11357-3:2013 (by DSC) and a crystallization enthalpy greater than 25 J / g, preferably greater than 40 J / g, according to standard ISO 11357-3 (2013) during the cooling step at a rate of 20 K / min (by DSC).

[0114] Tg, Tc and Tm are determined by differential scanning calorimetry (DSC) according to standards 11357-2:2013 and 11357-3:2013, respectively.

[0115] The number average molecular weight Mn of the semi-crystalline homopolyamide preferably extends in the range from 10,000 to 85,000, notably from 10,000 to 60,000, preferably from 10,000 to 50,000, even more preferably from 12,000 to 50,000. These Mn values can correspond to an intrinsic viscosity greater than or equal to 0.8 as determined in m-cresol according to standard ISO 307:2007 but with a change of solvent (using m-cresol instead of sulfuric acid and at a temperature of 20 °C).

[0116] The at least one homopolyamide or the at least one copolyamide comprises a reactive functional group selected from primary amines or carboxylic acids.

[0117] The at least one homopolyamide or the at least one copolyamide preferably has an amine (NH2) functional group concentration of from 0.020 meq / g to 2.0 meq / g, preferably from 0.035 meq / g to 0.5 meq / g, more preferably from 0.040 to 0.2 meq / g. The concentration of the NH2 functional group can be measured by potentiometry.

[0118] This determination can be carried out, for example, as follows: First, the PA is dissolved in m-cresol at 80 °C

[0119] and then the terminal NH2 functional groups are determined using a perchloric acid solution.

[0120] The at least one homopolyamide or the at least one copolyamide preferably has a COOH functional group concentration of from 0.020 meq / g to 2.0 meq / g, preferably from 0.035 meq / g to 0.5 meq / g, more preferably from 0.040 to 0.2 meq / g. The concentration of the COOH functional group can be determined by potentiometric analysis. The measurement procedure is described in detail in

[0121] the article “Synthesis and characterization of poly(copolyethers-block-polyamides)

[0122] - II. Characterization and properties of the multiblock copolymers”, Maréchal et al.

[0123] Polymer, Volume 41, 2000, 3561–3580.

[0124] The homopolyamide or copolyamide of the first composition and the polyamide with units (Ba1) of the second composition can be the same or different.

[0125] In the first variant, only one of the two compositions contains a filler, but the other does not contain any filler.

[0126] In the second variant, the first composition and the second composition contain the same polyamide, in particular PA11.

[0127] More precisely, according to this variant, the copolyamides with amide units (Ba1) and polyether units (Ba2) of the first composition and the second composition contain the same polyamide, in particular PA11. In other words, according to this embodiment, the polyamide portion of the copolyamide with amide units (Ba1) and polyether units (Ba2) of the second composition is the same as the polyamide of the first composition, in particular PA11.

[0128] In a third variant, at least 10% by weight, in particular at least 30% by weight, of the units of the at least one homopolyamide or the at least one copolyamide constituting the first composition and of the polyamide with units (Ba1) of the second composition are identical; in particular, the units are PA11 units.

[0129] In a fourth variant, the first composition and the second composition comprise the same polyamide, in particular PA11.

[0130] In one embodiment of these four variants, the long-chain homopolyamide of the first composition is selected from:

[0131] Polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1212), or a mixture thereof or a copolyamide thereof, in particular PA11 and PA12.

[0132] More particularly, the long-chain homopolyamide is selected from: polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1012 (PA1012), polyamide 1212 (PA1212), or a mixture thereof or a copolyamide thereof, in particular PA11 and PA12.

[0133] Even more particularly, the long-chain homopolyamide is polyamide 11.

[0134] In another embodiment of these four variants, the long-chain copolyamide is selected from 11 / 10T, 11 / BI, 11 / B10, 11 / BI / BT, 12 / BI, 1010 / B10 or a mixture thereof.

[0135] B corresponds to 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, which is also commonly referred to as BMACM or MACM.

[0136] PACM corresponds to bis(p-aminocyclohexyl)methane, which is also commonly referred to as P.

[0137] PACM is preferably PACM20, which is a mixture of isomers and contains approximately 20% of the trans-trans-PACM isomer, or PACM50, which is a mixture of isomers and contains approximately 50% of the trans-trans-PACM isomer.

[0138] In yet another embodiment of these four variants, the polyamide with amide units (Ba1) of the second composition is selected from:

[0139] Polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1212), or a mixture thereof or a copolyamide thereof, in particular PA11 and PA12.

[0140] More particularly, the polyamide with amide units (Ba1) of the second composition is selected from: polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1012 (PA1012), polyamide 1212 (PA1212), or a mixture thereof or a copolyamide thereof, in particular PA11 and PA12.

[0141] Even more particularly, the polyamide with amide units (Ba1) of the second composition is polyamide 11.

[0142] In yet another embodiment of these four variants, the long-chain homopolyamide of the first composition is selected from:

[0143] - polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1212), or a mixture thereof or a copolyamide thereof, in particular PA11 and PA12, and

[0144] the polyamide with amide units (Ba1) of the second composition is selected from:

[0145] polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1212), or a mixture thereof or a copolyamide thereof, in particular PA11 and PA12.

[0146] More particularly, the long-chain homopolyamide is selected from: polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1012 (PA1012), polyamide 1212 (PA1212), or a mixture thereof or a copolyamide thereof, in particular PA11 and PA12, and

[0147] the polyamide with amide units (Ba1) of the second composition is selected from: polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1012 (PA1012), polyamide 1212 (PA1212), or a mixture thereof or a copolyamide thereof, in particular PA11 and PA12.

[0148] Even more particularly, the long-chain homopolyamide is polyamide 11, and the polyamide with amide units (Ba1) of the second composition is polyamide 11.

[0149] In one embodiment, the first and second elements are selected from the following constituents: fabrics, films or textured films, foams, injection molded parts, extruded parts, 3D printed parts, adhesives, non-wovens, meshes and consolidated thermoplastic composite parts, preferably selected from fabrics, foams, injection molded parts, 3D printed parts, adhesives, non-wovens, meshes and consolidated thermoplastic composite parts.

[0150] According to one embodiment, the first and / or second element is different from a film.

[0151] According to one embodiment, the first and / or second element is different from an extruded part.

[0152] In another embodiment, the single-material object as defined above is characterized in that it consists of at least two different constituents as defined above.

[0153] In yet another embodiment, the single-material object as defined above is characterized in that it comprises at least three different constituents as defined above.

[0154] As described above, the first and second elements can be at least partially adhered to each other. When they are at least partially adhered to each other, the first and second elements are adhered to each other by bonding with a non-polyamide adhesive, the non-polyamide adhesive content ranging from 0.01% to 10% by weight, especially from 0.1% to 4% by weight, relative to the total mass of the object.

[0155] The adhesive can be a polyurethane, acrylic, acrylonitrile, polyester, polyisoprene, polybutadiene or vinyl adhesive, preferably selected from polyurethane, acrylic and polyester adhesives; advantageously, it corresponds to a polyurethane adhesive.

[0156] According to another embodiment, the single-material object of the present invention contains less than 0.1% by weight, preferably less than 0.01% by weight, and more particularly 0% by weight of non-polyamide adhesive.

[0157] In particular, they can contain less than 0.1% by weight, preferably less than 0.01% by weight, and more particularly 0% by weight of an encapsulated adhesion promoter (P), the adhesion promoter comprising at least one organic molecule which comprises at least two isocyanate functional groups which are closed by encapsulating the organic molecule, notably as defined in US 2011 / 0111208.

[0158] According to one embodiment, the monolithic object of the present invention comprises a dispersion of polyisocyanate in water and / or an organic solvent in an amount of less than 0.1% by weight, preferably less than 0.01% by weight, and more particularly 0% by weight, especially as defined in US 2011 / 0111208.

[0159] Preferably, when the monolithic object of the present invention comprises an adhesive, it is different from a dispersion in a solvent, especially a dispersion in water and / or in an organic solvent. In particular, when the monolithic object of the present invention comprises an adhesive, it is different from a dispersion in the solvent MEK (methyl ethyl ketone) and / or a C1-C5 alkyl acetate, especially ethyl acetate.

[0160] In particular, the monolithic object of the present invention comprises an adhesion promoter in an amount of less than 0.1% by weight, preferably less than 0.01% by weight, and more particularly 0% by weight, which adhesion promoter contains a solution of a polyurethane modified in a MEK + ethyl acetate solvent (dry extract - 30 min at 150 °C = 46.9% by mass of polyurethane).

[0161] Specifically, for environmental reasons, such non-polyamide adhesives should be avoided because they are somewhat toxic. Such non-polyamide adhesives also have a negative impact on the recyclability of the monolithic object according to the present invention because, as they are crosslinked and / or they cannot be easily separated and thus cannot be recycled.

[0162] In particular, as mentioned above, when thermoplastic polyurethane (TPU) is recycled, the formation of isocyanate can be observed by FTIR. However, isocyanate is a compound harmful to health and the environment (CMR classification), and in the context of the present invention, its formation is sought to be avoided.

[0163] In one embodiment, elements 1 and 2 are adhered to each other by a polyamide adhesive.

[0164] This may notably be a hot-melt adhesive composition comprising at least one copolyamide, such as those described in WO 2022 / 090665.

[0165] According to another embodiment, elements 1 and 2 are directly adhered to each other, i.e., without an adhesive.

[0166] The monolithic object as defined above may comprise at least one third replacement part composed of a third composition, which third composition comprises at least 50% by weight, advantageously 70% by weight, preferably 90% by weight, based on the total weight of the third element, of at least one long-chain homopolyamide or at least one long-chain copolyamide or a copolyamide with amide units (Ba1) and polyether units (Ba2) or a mixture thereof.

[0167] In one embodiment, the first and second elements are selected from the following constituents: fabric, film or textured film, foam, injection molded part, extruded part, 3D printed part, adhesive, nonwoven, mesh, and consolidated thermoplastic composite part.

[0168] In another embodiment, the single-material object as defined above is characterized in that it consists of at least two different constituents as defined above.

[0169] In yet another embodiment, the single-material object as defined above is characterized in that it contains at least three constituents as defined above, especially different constituents.

[0170] As shown above, the first element and the second element can be at least partially adhered to each other.

[0171] When they are at least partially adhered to each other, the first and second elements are adhered to each other by the adhesion of a non-polyamide adhesive, and the content of the polyamide adhesive ranges from 0.01% to 10% by weight, especially 0.1% to 4% by weight, based on the total mass of the object.

[0172] The single-material object as defined above may contain at least one third element, and the third element is composed of a third composition, and the third composition contains

[0173] at least one long-chain homopolyamide or at least one long-chain copolyamide or at least one copolyamide having amide units (Ba1) and polyether units (Ba2) or a mixture thereof, and the at least one copolyamide having amide units (Ba1) and polyether units (Ba2) is as defined above.

[0174] In one embodiment, the third composition contains at least 50% by weight, advantageously 70% by weight, preferably 90% by weight of at least one long-chain homopolyamide or at least one long-chain copolyamide or at least one copolyamide having amide units (Ba1) and polyether units (Ba2) or a mixture thereof, based on the total weight of the third element.

[0175] The copolyamide (PEBA) having amide units (Ba1) and polyether units (Ba2) of the compositions of the second and third elements

[0176] Polyether block amide (PEBA) is a copolymer containing amide units (Ba1) and polyether units (Ba2), and the amide units (Ba1) correspond to aliphatic repeating units, and the aliphatic repeating units are selected from the units obtained from at least one amino acid or the units obtained from at least one lactam, or the units X.Y obtained from the polycondensation of the following:

[0177] - at least one diamine, preferably selected from linear or branched aliphatic diamines, or mixtures thereof, and

[0178] - at least one dicarboxylic acid, preferably selected from:

[0179] - linear or branched aliphatic dicarboxylic acids or mixtures thereof,

[0180] the diamine and the dicarboxylic acid contain from 4 to 36 carbon atoms, advantageously from 6 to 18 carbon atoms;

[0181] the polyether unit (Ba2) is notably obtained from at least one polyalkylene ether polyol, notably a polyalkylene ether diol.

[0182] PEBA is notably produced by polycondensation of a polyamide block with reactive ends and a polyether block with reactive ends, for example, in particular:

[0183] 1) A polyamide block with diamine chain ends and a polyoxyalkylene block with dicarboxylic acid chain ends.

[0184] 2) A polyamide block with dicarboxylic acid chain ends and a polyoxyalkylene block with diamine chain ends, obtained by cyanoethylation and hydrogenation of an aliphatic α,ω-dihydroxylated polyoxyalkylene block called a polyalkylene ether diol (polyether diol).

[0185] 3) A polyamide block with dicarboxylic acid chain ends and a polyether diol, and the product obtained is a polyether ester amide in this particular case. The copolymer of the present invention is advantageously of this type.

[0186] The polyamide block with dicarboxylic acid chain ends, for example, originates from the condensation of a polyamide precursor in the presence of a chain-limiting dicarboxylic acid.

[0187] The polyamide block with diamine chain ends, for example, originates from the condensation of a polyamide precursor in the presence of a chain-limiting diamine.

[0188] Polymers having polyamide blocks and polyether blocks may also contain randomly distributed units. These polymers can be prepared by the simultaneous reaction of precursors of polyethers and polyamide blocks.

[0189] For example, a polyether diol, a polyamide precursor, and a chain-limiting dicarboxylic acid can be reacted. The polymer obtained basically has polyamide blocks and polyether blocks of very variable lengths, but also various reagents that react randomly, which are randomly (statistically) distributed along the polymer chain.

[0190] A polyether diamine, a polyamide precursor, and a chain-limiting dicarboxylic acid can also be reacted. The polymer obtained basically has polyamide blocks and polyether blocks of very variable lengths, but also various reagents that react randomly, which are randomly (statistically) distributed along the polymer chain.

[0191] Amide unit (Ba1):

[0192] The amide unit (Ba1) corresponds to the aliphatic repeating unit defined above.

[0193] Advantageously, the amide unit (Ba1) is selected 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, especially polyamide 11.

[0194] More advantageously, the amide unit (Ba1) is selected from polyamide 11 and polyamide 12, especially polyamide 11.

[0195] The amide unit (Ba1) contains less than 20% by weight, advantageously less than 10% by weight, preferably less than 5% by weight, notably less than 2% by weight of polyamides having a CN ratio less than or equal to 8.

[0196] Polyether unit (Ba2):

[0197] The polyether unit notably derives from at least one polyalkylene ether polyol, in other words, the polyether unit is formed by at least one polyalkylene ether polyol. In this embodiment, the term "at least one polyalkylene ether polyol" means that the polyether unit consists only of alcohol chain ends and thus cannot be a polyether diamine triblock type compound.

[0198] Thus, the composition of the invention does not contain polyether diamine triblocks.

[0199] According to one embodiment, the copolyamide with amide unit (Ba1) and polyether unit (Ba2) of the second composition mainly contains, that is, more than the total weight of the polyether units, polyether units (Ba2) having a C / O ratio to be 3 and greater than 3.5.

[0200] The copolyamide with amide unit (Ba1) and polyether unit (Ba2) of the second composition may notably contain at least 80% by weight, or even 100% by weight of polyether units (Ba2) having a C / O ratio greater than 3, for example greater than 3.5, based on the total weight of the polyether units.

[0201] Advantageously, the polyether unit (Ba2) is selected from polyethylene glycol (PEG), polypropylene glycol (PPG), polytrimethylene glycol (PO3G), polytetramethylene glycol (PTMG) and their mixtures or copolymers, especially PTMG.

[0202] According to one embodiment, the polyether unit (Ba2) of the copolyamide with amide units (Ba1) and polyether units (Ba2) present in the second element of the monomaterial object of the present invention contains less than 20% by weight, preferably less than 10% by weight, advantageously less than 5% by weight, notably less than 2% by weight of the copolyamide with amide units (Ba1) and short-chain polyether units (Ba2), i.e., the polyether unit has a C / O ratio of less than or equal to 3, notably less than or equal to 2.

[0203] For the purposes of the present invention, the C / O ratio corresponds to the ratio between the number of carbon atoms and the number of oxygen atoms in the polyether unit.

[0204] According to one embodiment, the polyether unit (Ba2) of the copolyamide with amide units (Ba1) and polyether units (Ba2) present in the second element of the monomaterial object of the present invention contains less than 20% by weight, preferably less than 10% by weight, advantageously less than 5% by weight, especially less than 2% by weight of polyethylene glycol (PEG), polypropylene glycol (PPG) and / or polytrimethylene glycol (PO3G), especially polyethylene glycol (PEG).

[0205] According to one embodiment, the monomaterial object of the present invention contains less than 20% by weight, preferably less than 10% by weight, for example less than 5% by weight, for example less than 3% by weight, especially 0% by weight of the copolyamide with amide units (Ba1) and short-chain polyether units (Ba2), i.e., the polyether unit has a C / O ratio of less than or equal to 3, especially less than or equal to 2.

[0206] In one embodiment, the (Ba2) unit does not contain (i.e., contains less than 0.1% by weight, preferably 0% by weight) polyethylene glycol (PEG), polypropylene glycol (PPG) and / or polytrimethylene glycol (PO3G), especially polyethylene glycol (PEG).

[0207] Advantageously, a low water absorption rate and thus a lower density of the monomaterial object of the present invention are observed during use when the latter contains little or even no copolyamide with amide units (Ba1) and short-chain polyether units (Ba2) (i.e., the polyether unit has a C / O ratio of less than or equal to 3, notably less than or equal to 2).

[0208] The number-average molecular weight (Mn) of the polyether block is advantageously from 200 to 4000 g / mol, preferably from 250 to 2500 g / mol, especially from 300 to 1100 g / mol.

[0209] The PEBA can be prepared by the following method, wherein:

[0210] - In a first step, a polyamide block (Ba1) is prepared by polycondensation as follows in the presence of a chain limiter selected from dicarboxylic acids

[0211] lactam, or

[0212] amino acid, or

[0213] diamine and dicarboxylic acid; and, where appropriate, comonomers selected from lactams and α,ω-aminocarboxylic acids;

[0214] and then

[0215] - In a second step, the polyamide block (Ba1) obtained is reacted with a polyether block (Ba2) in the presence of a catalyst.

[0216] The two-step general method for preparing the copolymer of the invention is known and is described, for example, in French Patent FR 2 846 332 and European Patent EP 1 482 011.

[0217] The reaction for forming block (Ba1) is generally carried out at 180 °C to 300 °C, preferably 200 °C to 290 °C, and the pressure in the reactor is brought to 5 bar to 30 bar and maintained for about 2 hours to 3 hours. The pressure is slowly reduced while the reactor is returned to atmospheric pressure and then, for example, the excess water is evaporated off within 1 or 2 hours.

[0218] Once the polyamide with carboxylic acid end groups has been prepared, then the polyether and the catalyst are added. The polyether can be added in one or more portions, and so can the catalyst. According to an advantageous form, the polyether is added first; the reaction between the OH end groups of the polyether and the COOH end groups of the polyamide begins with the formation of an ester bond and the elimination of water. As much water as possible is removed from the medium by distillation, and then the catalyst is introduced to complete the linking of the polyamide block and the polyether block. This second step is carried out with stirring, preferably under a vacuum of at least 15 mmHg (2000 Pa), at a temperature such that the reagents and the copolymer obtained are in a molten form. For example, this temperature can be 100 °C to 400 °C, and more commonly 200 °C to 300 °C. Monitoring is carried out by measuring the torque exerted on the stirrer by the molten polymer or by measuring the electrical power consumed by the stirrer. The end of the reaction is determined by the target torque or power value.

[0219] During the synthesis, one or more molecules used as antioxidants, such as Irganox ® 1010 or Irganox ® 245, can also be added at the moment considered to be most appropriate.

[0220] A PEBA preparation method can also be considered, which involves adding all the monomers at the start, i.e., in a single step, to effect the following polycondensation:

[0221] lactam, or

[0222] amino acid, or

[0223] diamine and dicarboxylic acid; and, if appropriate, other polyamide comonomers;

[0224] - in the presence of a chain limiter selected from dicarboxylic acids;

[0225] - in the presence of a (Ba2)(polyether) block;

[0226] - in the presence of a catalyst for between the flexible (Ba2) block and the (Ba1) block.

[0227] Advantageously, the dicarboxylic acid is used as a chain limiter and is introduced in a stoichiometric excess relative to the diamine.

[0228] Advantageously, derivatives of metals formed from titanium, zirconium and hafnium selected, or strong acids such as phosphoric acid, hypophosphorous acid or boric acid are used as catalysts.

[0229] The polycondensation can be carried out at a temperature of 240 to 280 °C.

[0230] Generally, known copolymers with ether and amide units consist of copolymers of semi-crystalline linear, aliphatic polyamide blocks (such as Pebax from Arkema).

[0231] In one embodiment, the copolyamide with amide units (Ba1) and polyether units (Ba2) has a density greater than or equal to 1, in particular greater than or equal to 1.01, notably greater than or equal to 1.02, as determined according to ISO 1183-3:1999.

[0232] In one embodiment, polyetheramine is excluded from the polyether units (Ba2).

[0233] In one embodiment, the copolyamide with amide units (Ba1) and polyether units (Ba2) present in the first composition of the first element constituting the single-material object of the present invention has a Shore D hardness less than or equal to 50 D, notably less than or equal to 45 D.

[0234] Regarding the single-material object

[0235] It consists of at least two elements: said at least one first element defined herein as (E1) and said at least one second element defined herein as (E2).

[0236] In a first variant, it consists of two said elements: E1 / E2.

[0237] Element E1 can be at least partially adhered to element E2; in particular, E1 and E2 are at least partially adhered and in particular E1 and E2 are fully adhered, in particular by an adhesive.

[0238] Then select a single-material object from those mentioned above.

[0239] In a second variant, it consists of more than two elements: E1 / (E1)n / E2 / (E2)m, where n and m are from 0 to 5, and when n = 0, then m > 0, and when m = 0, then n > 0.

[0240] Needless to say, when two elements of E1 or two elements of E2 are side by side, they can be at least partially adhered together.

[0241] In one embodiment, the homopolyamide or copolyamide of element E1 and the homopolyamide of element E2 contain the same monomers, notably at least 5% by weight, advantageously at least 10% by weight, preferably at least 30% by weight of the same monomers, such as 11-aminoundecanoic acid, relative to the sum of the constituents of the said homopolyamide or copolyamide.

[0242] In one embodiment, the homopolyamide or copolyamide of element E1 and the homopolyamide of element E2 are composed of monomers having the same C / N ratio, notably composed of at least 5% by mass, advantageously 10% by mass, preferably 30% by mass of monomers having the same C / N ratio relative to the sum of the constituents of the said homopolyamide or copolyamide.

[0243] In a third variant, it can consist of more than two elements: the at least one first element defined herein as (E1) and the at least one second element defined herein as (E2) and the third element defined herein as E3.

[0244] In one embodiment, it consists of three elements: E1 / E2 / E3 or E1 / E3 / E2 or E3 / E1 / E2.

[0245] Element E1 can be at least partially adhered to element E2; in particular, E1 and E2 are at least partially adhered, in particular E1 and E2 are fully adhered, in particular by an adhesive.

[0246] Element E2 can be at least partially adhered to element E3; in particular, E2 and E3 are at least partially adhered, in particular E2 and E3 are fully adhered, in particular by an adhesive.

[0247] If there is at least one other element E1 and / or E2 and / or E3 in the said single-material object, it is not outside the scope of the invention.

[0248] In a first variant, the first element is of non-recycled origin.

[0249] In a second variant, the second element is of non-recycled origin.

[0250] In a third variant, the third element (if present) is of non-recycled origin.

[0251] In a fourth variant, the first and second elements are of non-recycled origin.

[0252] In a fifth variant, the first and third elements (when they are present) are of non-recycled origin.

[0253] In a sixth variant, the second and third elements (when they are present) are of non-recycled origin.

[0254] In a seventh variant, the first, second and third elements (when present) are of non-recycled origin.

[0255] In an eighth variant, the first element is at least partially of recycled origin.

[0256] In a ninth variant, the second element is at least partially of recycled origin.

[0257] In a tenth variant, the third element (if present) is at least partially of recycled origin.

[0258] In an eleventh variant, the first and second elements are at least partially of recycled origin.

[0259] In a twelfth variant, the first and third elements (when they are present) are at least partially of recycled origin.

[0260] In a thirteenth variant, the second and third elements (when they are present) are at least partially of recycled origin.

[0261] In a fourteenth variant, the first, second and third elements (when they are present) are at least partially of recycled origin.

[0262] The term "at least partially recycled" means that there is at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% of a recycled composition in the element, and the recycled composition itself contains at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% of a long-chain homopolyamide or copolyamide or a copolyamide with amide units (Ba1) and polyether units (Ba2) of recycled origin.

[0263] In one embodiment, when the single material is composed of three or more elements, the composition of the third element comprises at least one long-chain homopolyamide or at least one long-chain copolyamide.

[0264] In another embodiment, when the single material is composed of three or more elements, the composition of the third element (E3) comprises at least one copolyamide having amide units (Ba1) and polyether units (Ba2).

[0265] In yet another embodiment, when the single material is composed of three or more elements, the composition of the third element comprises a blend of at least one long-chain homopolyamide or at least one long-chain copolyamide and at least one copolyamide having amide units (Ba1) and polyether units (Ba2).

[0266] In another embodiment, the composition of the first element (E1) comprises a single long-chain homopolyamide or at least one long-chain copolyamide.

[0267] In another embodiment, the composition of the second element (E2) comprises a single copolyamide having amide units (Ba1) and polyether units (Ba2).

[0268] In another embodiment, the composition of the third element (E3) (if present) comprises a single long-chain homopolyamide or at least one long-chain copolyamide.

[0269] In another embodiment, the composition of the third element (E3) (if present) comprises a single copolyamide having amide units (Ba1) and polyether units (Ba2).

[0270] In another embodiment, the composition of the first element (E1) comprises a single long-chain homopolyamide or at least one long-chain copolyamide, and the composition of the second element (E2) comprises a single copolyamide having amide units (Ba1) and polyether units (Ba2).

[0271] In another embodiment, the composition of the first element (E1) comprises a single long-chain homopolyamide or at least one long-chain copolyamide, the composition of the second element (E2) comprises a single copolyamide having amide units (Ba1) and polyether units (Ba2), and the composition of the third element (E3) (if present) comprises a single long-chain homopolyamide or at least one long-chain copolyamide.

[0272] In another embodiment, the composition of the first element (E1) comprises a single long-chain homopolyamide or at least one long-chain copolyamide, and the composition of the second element (E2) comprises a single copolyamide with amide units (Ba1) and polyether units (Ba2), and the composition of the third element (E3) (if present) comprises a single copolyamide with amide units (Ba1) and polyether units (Ba2).

[0273] According to another aspect, the present invention relates to a method for manufacturing a single-material object as defined above, which comprises steps, the steps comprising:

[0274] - providing a first element consisting of a first composition, the first composition comprising at least 30% by weight, notably at least 50% by weight, particularly at least 70% by weight, more particularly at least 90% by weight of at least one long-chain homopolyamide or at least one long-chain copolyamide as defined above, relative to the total weight of the first element,

[0275] - providing a second element consisting of a second composition, the second composition comprising at least 30% by weight, notably at least 50% by weight, particularly at least 70% by weight, more particularly at least 90% by weight of at least one copolyamide with amide units (Ba1) and polyether units (Ba2) as defined above, relative to the total weight of the second element,

[0276] assembling the elements of the object by an adhesive, where appropriate, to form a finished or semi-finished object.

[0277] In one embodiment, the method as defined above comprises an additional step of providing a third element consisting of a third composition before assembly, the third composition comprising at least 30% by weight, particularly at least 50% by weight, particularly at least 70% by weight, more particularly at least 90% by weight of at least one long-chain homopolyamide or at least one long-chain copolyamide as defined above, or at least one copolyamide with amide units (Ba1) and polyether units (Ba2), or a mixture of the two, relative to the total weight of the third element.

[0278] In the case of a semi-finished product, a step of adding other elements is carried out, which other elements cannot be recycled by the method of the invention but are preferably easily separable from the elements of the invention (such as the electronics of a watch).

[0279] According to another aspect, the present invention relates to a method for recycling an object as defined above, comprising steps, the steps comprising the following:

[0280] (a) providing a used object,

[0281] (b) optionally separating the elements of the object that are not recyclable in the method,

[0282] (c) Optionally, clean the used object from step (a) or (b).

[0283] (d) Optionally, first grind the used object from step (a) or (b), or the used object of step (c) when performing the cleaning of step (c), to obtain a first grinding material.

[0284] (e) When not performing the cleaning of step (c), optionally wash the ground material.

[0285] (f) Grind the used object from step (a) and / or (b) and / or (c) and / or (d) and / or (e) in order to obtain a first grinding material or a second grinding material in the case where the first grinding in step (d) has been performed.

[0286] (g) Heat the grinding material from step (f) until it melts.

[0287] (h) Optionally, compound and

[0288] (i) Extrude or injection mold the molten material.

[0289] The first and / or second grinding may or may not be performed before or after cleaning.

[0290] The cleaning is carried out by means of compressed air, especially under pressure, or by means of hot water or steam from the structure.

[0291] Cleaning with compressed air allows non-polymeric particles such as dirt, sand or dust to be removed from the used object.

[0292] Cleaning with hot water or steam allows at least partial dissolution and removal of the water-soluble substances of the used object in order to obtain the other components of the used object.

[0293] The temperature of the hot water or steam is from 70 °C to 150 °C, especially from 70 °C to 120 °C.

[0294] The hot water may have a pH of 1 to 12.

[0295] The compounding step (h) allows the addition of an impact modifier and / or a filler and / or an additive and / or a plasticizer.

[0296] If step (h) is carried out, the material obtained after said step (h) is in the form of granules for subsequent extrusion or injection molding.

[0297] The term "used object" means an object that is no longer new and has been used or has been put to use, but in no case does it mean such a post-industrial object that would be recycled without having been used or put to use. Thus, the term "used object" particularly encompasses aged objects.

[0298] In another embodiment, the present invention relates to the recycling method as defined above and further comprises the following steps:

[0299] (j) adding new material to the grinding material of the used object before or after step (f) or after step (g).

[0300] The term "new material" means both another polymer, particularly another polyamide, particularly a polyamide with C / N < 8, and fillers and additives.

[0301] At least one dimension (selected from length, width, and thickness), preferably at least two dimensions (selected from length, width, and thickness), or even all three dimensions of the single-material object are greater than 1 mm, preferably greater than 2 mm, and advantageously greater than 3 mm. This allows for better recyclability, particularly by grinding and / or compounding.

[0302] Regarding additives

[0303] Additives are optional and account for 0 wt% to 20 wt%, particularly 0.1 wt% to 5 wt%.

[0304] Additives are selected from dyes, stabilizers, plasticizers, surfactants, nucleating agents, pigments, brighteners, antioxidants, lubricants, flame retardants, natural waxes, impact modifiers, additives for laser marking, and mixtures thereof.

[0305] According to one embodiment, the single-material object of the present invention, and particularly the first composition constituting the first element and / or the second composition constituting the second element, contains less than 2 wt% of carbon black, preferably less than 1 wt% of carbon black, and preferably less than 0.1 wt% of carbon black, based on its total weight. Advantageously, the single-material object of the present invention, and particularly the first composition constituting the first element and / or the second composition constituting the second element, does not contain (i.e., contains 0 wt%) carbon black, based on its total weight.

[0306] Regarding fillers

[0307] Regarding fillers, these are reinforcing fibers, which are notably fibers of mineral, organic, or plant origin.

[0308] The reinforcing fibers may or may not be sized.

[0309] Thus, the reinforcing fibers may comprise up to 0.1% by weight of an organic (thermosetting or thermoplastic resin type) material called a sizing agent.

[0310] Among the fibers of mineral origin, mention may be made, for example, of carbon fibers, glass fibers, basalt fibers or basalt-based fibers, silica fibers or silicon carbide fibers. Among the fibers of organic origin, mention may be made, for example, of fibers based on thermoplastic or thermosetting polymers, such as semi-aromatic polyamide fibers, aramid fibers or polyolefin fibers. Preferably, they are based on amorphous thermoplastic polymers and, when the polymer or blend is amorphous, their glass transition temperature Tg is greater than that of the thermoplastic polymer or polymer blend constituting the pre-impregnated matrix, or when the polymer or blend is semi-crystalline, their glass transition temperature Tg is greater than the Tm of the thermoplastic polymer or polymer blend constituting the pre-impregnated matrix. Among the fibers of plant origin, mention may be made of natural fibers based on flax, hemp, lignin, bamboo, silk, especially spider silk, sisal, and other cellulose fibers, especially viscose fibers. For the purpose of promoting the adhesion and impregnation of the thermoplastic polymer matrix, these fibers of plant origin can be used in pure form, treated or coated.

[0311] Preferably, the reinforcing fibers are selected from glass fibers, carbon fibers, basalt fibers and basalt-based fibers.

[0312] Advantageously, the reinforcing fibers are selected from carbon fibers and glass fibers.

[0313] In one embodiment, the reinforcing fibers present in a) are glass fibers.

[0314] The glass fibers may have a circular or non-circular cross-section.

[0315] Fibers with a circular cross-section are defined as fibers having an equal distance from the center of the fiber at any point on its circumference, thus representing a perfect or nearly perfect circle.

[0316] Thus, any glass fiber that does not have such a perfect or nearly perfect circle is defined as a fiber having a non-circular cross-section.

[0317] Examples of fibers with a non-circular cross-section are not limited to non-circular fibers, such as oval, egg-shaped or cocoon-shaped, star-shaped fibers, flake-shaped fibers, flat fibers, cross-shaped, polygonal and annular.

[0318] The glass fibers may be:

[0319] - of circular cross-section with a diameter of 4 μm to 25 μm, preferably 4 μm to 15 μm;

[0320] - or a non-circular cross-section with an L / D ratio (where L represents the maximum dimension of the cross-section of the fiber and D represents the minimum dimension of the cross-section of the fiber) of from 2 to 8, in particular from 2 to 4. L and D can be measured by scanning electron microscopy (SEM).

[0321] Advantageously, the glass fibers are circular.

[0322] The glass fibers are notably of type E, R, S2 or T. Advantageously, the glass fibers are of type E.

[0323] In another embodiment, the filler is present in an amount of 0 - 65%.

[0324] In one embodiment, the filler is recycled.

[0325] In the case where the filler comprises glass, they can notably be made from industrial production waste or post-consumer glass.

[0326] The carbon fibers can for example come from the cutting of rolls of expired long fibers, in particular carbon fibers for aviation.

[0327] Advantageously, the filler is selected from glass fibers, in particular circular glass fibers, and carbon fibers, in particular glass fibers, notably circular glass fibers.

[0328] According to another aspect, the present invention relates to a recycled polyamide composition obtainable by the method defined above.

[0329] According to another aspect, the present invention relates to a composition comprising, by weight:

[0330] - 30% to 100%, advantageously 50% to 99%, of recycled polyamide from the single-material objects defined above,

[0331] - 0 to 70% of virgin polyamides selected from homopolyamides, in particular long-chain homopolyamides, copolyamides, in particular long-chain copolyamides, and PEBA; advantageously, the virgin polyamide is a homopolyamide, in particular a long-chain homopolyamide,

[0332] 0 to 65% of filler,

[0333] 0 to 20%, in particular 0.1% to 5%, of additives,

[0334] The sum of the components is equal to 100%,

[0335] The recycled polyamide has functional groups resulting from an oxidation reaction, the functional groups being selected from primary amide functional groups, nitriles, chain-end methyl groups, olefins, formamides, imides, carboxylic acids, and alcohols and mixtures thereof, the molar ratio thereof relative to the amide functional groups being greater than that of the same polyamide constituting a virgin article that has never been used.

[0336] The term "recycled polyamide derived from a single-material article as defined above" is intended to mean a polyamide derived from a single-material article that is no longer new (which has been used or has been put into use), but in no case does it mean such a post-industrial article that would be recycled without having been used or put into use. Contrary to "virgin" polyamide, "recycled" polyamide specifically encompasses aged polyamide.

[0337] When using a single-material article, new substances resulting from an oxidation mechanism are seen in the polyamide constituting the single-material article, in particular amide functional groups and / or the methylene in the alpha position of the amide functional groups, such as imide functional groups, carboxylic acids, primary amides, and alcohols.

[0338] The functional groups are considered to be the result of UV radiation or heat or the reaction of compounds in contact with the article. For example, gasoline, sunscreen, lubricants, etc.

[0339] The functional groups can be detected by infrared or NMR spectroscopy.

[0340] Thus, the absorption band at 1700 to 1740 cm -1 corresponds to imide, the absorption band at 1680 to 1720 cm -1 corresponds to the carbonyl group of carboxylic acid and the absorption band at 3580 to 3670 cm -1 corresponds to the alcohol functional group of carboxylic acid.

[0341] The absorption band at 3580 to 3670 cm -1 corresponds to the free alcohol functional group.

[0342] The amide functional group is characterized first by a pair of absorption bands at 3100 to 3500 cm -1 and 1560 to 1640 cm -1 which correspond to the NH group of the amide, and second by the absorption band at 1650 to 1700 cm -1 which corresponds to the carbonyl group of the amide.

[0343] In a first variant, the composition comprises, by weight:

[0344] 50% to 70% of recycled polyamide from a single-material article as defined above,

[0345] 30% to 50% of virgin polyamides selected from homopolyamides, in particular long-chain homopolyamides, copolyamides, in particular long-chain copolyamides, and PEBA; advantageously, the virgin polyamide is a homopolyamide,

[0346] 0 to 20%, in particular 0.1% to 5%, of additives,

[0347] The sum of the components is equal to 100%.

[0348] In a second variant, the composition comprises by weight:

[0349] 30% to 50% of polyamide recycled from the single-material objects defined above,

[0350] 0 to 65% of virgin polyamides selected from homopolyamides, in particular long-chain homopolyamides, copolyamides, in particular long-chain copolyamides, and PEBA; advantageously, the virgin polyamide is a homopolyamide, in particular a long-chain homopolyamide,

[0351] 5 to 60% of fillers,

[0352] 0 to 20%, in particular 0.1% to 5%, of additives,

[0353] The sum of the components is equal to 100%.

[0354] In a third variant, the composition comprises by weight:

[0355] 60% to 80% of polyamide recycled from the single-material objects defined above,

[0356] 0 to 20% of virgin polyamides selected from homopolyamides, in particular long-chain homopolyamides, copolyamides, in particular long-chain copolyamides, and PEBA; advantageously, the virgin polyamide is a homopolyamide, in particular a long-chain homopolyamide,

[0357] 20 to 40% of fillers,

[0358] 0 to 20%, in particular 0.1% to 5%, of additives,

[0359] The sum of the components is equal to 100%.

[0360] In a fourth variant, the composition comprises by weight:

[0361] 40% to 60% of polyamide recycled from the single-material objects defined above,

[0362] 0 to 20% of virgin polyamides selected from homopolyamides, in particular long-chain homopolyamides, copolyamides, in particular long-chain copolyamides, and PEBA; advantageously, the virgin polyamide is a homopolyamide, in particular a long-chain homopolyamide,

[0363] 40 to 60% of fillers,

[0364] 0 to 20%, in particular 0.1% to 5% of additives,

[0365] The sum of the components is equal to 100%.

[0366] In one embodiment, in the compositions of this other aspect and its four variants, the term "comprising" is replaced by the term "consisting of".

[0367] The compositions of these four variants and their embodiments are compositions particularly suitable for such embodiments in which the single-material object defined above is characterized in that only one of the two compositions contains fillers and the other does not contain fillers.

[0368] Recycled polyamides have unique characteristics, and when they are derived from an object as previously defined, it is notable the new substances generated by an oxidation mechanism.

[0369] For the purposes of the invention, the term "new substances generated by an oxidation mechanism" is intended to denote formate (formate ester) functional groups, chain-end methyls, primary amides, nitriles, olefins, formamides, carboxylic acids, aldehydes, imides, and alcohols visible in the recycled polyamides of the present invention.

[0370] The recycled polyamides of the present invention have functional groups generated by an oxidation reaction selected from formate functional groups, chain-end methyls, primary amides, nitriles, olefins, formamides, carboxylic acids, aldehydes, imides, and alcohols.

[0371] According to a preferred embodiment of the present invention, the recycled polyamides of the present invention have functional groups obtained from an oxidation reaction, which are selected from formate functional groups, chain-end methyls, primary amides, and nitriles.

[0372] According to a preferred embodiment of the present invention, the recycled polyamides of the present invention have functional groups generated by an oxidation reaction selected from formate functional groups and chain-end methyls, the molar ratio of which to the secondary amide functional group is higher than that molar ratio of the same virgin polyamide.

[0373] These functional groups can be identified and quantified using infrared and / or proton or carbon NMR spectroscopy.

[0374] NMR measurements can be carried out in a HFIP / CD2Cl2 mixture. For example, 20 mg of the polymer can be dissolved in 0.7 mL of solvent with a HFIP / CD2Cl2 ratio of 1 / 3. A dichloromethane (CD2Cl2) / trifluoroacetic anhydride (ATFA) mixture can also be used.

[0375] This method is described in Chapter II.2.3 of the Ph.D. thesis of E. Goncalves published in 2011, which is incorporated herein by reference. Analysis in these two solvents allows the identification of most of the functional groups formed during the lifetime of the polyamide.

[0376] Thus, by way of example, in the infrared spectrum, absorption bands from 1700 to 1740 cm -1 correspond to imides, absorption bands from 1680 to 1720 cm -1 correspond to the carbonyl group of carboxylic acids and absorption bands from 3580 to 3670 cm -1 correspond to the alcohol functional group of carboxylic acids.

[0377] Absorption bands from 3580 to 3670 cm -1 correspond to free alcohol functional groups.

[0378] The amide functional group is characterized firstly by a pair of absorption bands from 3100 to 3500 cm -1 and from 1560 to 1640 cm -1 which correspond to the NH group of the amide, and secondly by an absorption band from 1650 to 1700 cm -1 which corresponds to the carbonyl group of the amide.

[0379] Absorption bands at 1180 and 1723 cm -1 correspond to formate. Bands at 900 and 1660 cm -1 correspond to alkenes.

[0380] For example, the degradation of polyethers included in polyamide elastomers (especially PEBA) can be quantified by infrared spectroscopy by comparing the intensity ratio between the band at 1111 cm -1 (vibration of the C-O bond of the ether group) or the band at 2791 cm -1 (CH2 at the α position of the ether functional group) and the band at 1725 cm -1 (carbonyl functional group).

[0381] Quantification by NMR is carried out, for example, in the context of proton NMR by comparing the intensity of the line of the functional group that is absent in the unused polymer with the line corresponding to CH2 at the α position of the amide. In carbon NMR, the intensity of the line of the functional group formed during the lifetime of the polymer is compared with the intensity of the line of the amide or CH2 carbon.

[0382] For example, some of the above functional groups can be observed in 13C NMR in HFIP / CD2Cl2 solvent. Thus, the line at 36 ppm corresponds to the CH2 at the α-position of the primary amide, and the line at 34 ppm corresponds to the CH2 at the α-position of the carboxylic acid. These substances can be quantified by integrating the area under this line and comparing it with the area under the line at 37.1 ppm corresponding to the secondary amide. Similarly, lines corresponding to the carbonyl groups of the primary amide, carboxylic acid, and secondary amide functional groups are observed at 181.2 ppm, 179.6 ppm, and 177.4 ppm, respectively. The line at 16.7 ppm corresponds to the CH2 at the α-position of the nitrile group. The formamide group gives chemical shifts at 163.0 ppm and 166.3 ppm.

[0383] As described above, other functional groups mentioned above can be observed in proton NMR ( 1 H NMR) in HFIP / CD2Cl2 solvent. The lines of the formamide CHO group appear at 7.92 and 8.01 ppm. The line corresponding to the CH2 group at the α-position of the primary amide can be observed at 2.30 ppm. The 0.9 ppm line corresponds to the CH3 group of the CH3-(CH2)n type. The line at 2.40 ppm corresponds to the CH2 at the α-position relative to the nitrile functional group. The line corresponding to the proton of the formate functional group is observed at 8.1 ppm. The line corresponding to the proton of the aldehyde functional group is observed at 9.7 ppm. Similar to that described for carbon NMR, the ratio of the new functional group relative to the secondary amide can be determined by integrating the area under this line and comparing it with the area under the line corresponding to the CH2 at the α-position of the secondary amide (2.20 ppm) or with the area under the line corresponding to the CONH proton of the secondary amide (6.0 - 6.1 ppm).

[0384] According to any of the embodiments of the present invention, in the recycled polyamide of the present invention, the molar ratio of the functional groups generated by the oxidation reaction to the secondary amide functional group is from 0.0005 to 0.3.

[0385] According to any of the embodiments of the present invention, in the recycled polyamide of the present invention, the molar ratio of the formate alcohol functional group to the secondary amide functional group is from 0.0005 to 0.2, particularly from 0.001 to 0.08, particularly from 0.005 to 0.05.

[0386] According to any of the embodiments of the present invention, in the recycled polyamide of the present invention, the molar ratio of the chain-end methyl to the secondary amide functional group is from 0.0005 to 0.2, particularly from 0.001 to 0.08, particularly from 0.005 to 0.05.

[0387] According to any of the embodiments of the present invention, in the recycled polyamide of the present invention, the molar ratio of the primary amide functional group to the secondary amide functional group is from 0.0005 to 0.1, particularly from 0.001 to 0.08, particularly from 0.005 to 0.05.

[0388] Needless to say, as a function of the waste product and the exposure it has undergone, one or more functional groups resulting from the oxidation reaction may be present.

[0389] In one embodiment, the molar ratio of the functional groups resulting from the oxidation reaction to the secondary amide functional group is from 1 / 10000 to 1 / 20.

[0390] The concentration can be measured by proton NMR in dichloromethane-d2, where HFIP (hexafluoroisopropanol) is added to dissolve the polyamide.

[0391] In a first variant, the molar ratio of the imide functional group is from 1 / 1000 to 1 / 20, notably from 1 / 500 to 1 / 20, particularly from 1 / 200 to 1 / 50.

[0392] In a second variant, the molar ratio of the carboxylic acid functional group is from 1 / 5000 to 1 / 20, notably from 1 / 3000 to 1 / 50, very advantageously from 1 / 500 to 1 / 15.

[0393] In a third variant, the molar ratio of the alcohol functional group is from 1 / 1000 to 1 / 20, advantageously from 1 / 1000 to 1 / 25, very advantageously from 1 / 200 to 1 / 50.

[0394] In a fourth variant, the molar ratio of the primary amide functional group to the secondary amide functional group is from 1 / 2000 to 1 / 20, advantageously from 1 / 1000 to 1 / 100 and very advantageously from 1 / 1000 to 1 / 500.

[0395] In a fifth variant, the molar ratio of the nitrile functional group to the secondary amide functional group is from 1 / 1000 to 1 / 20, advantageously from 1 / 500 to 1 / 15 and very advantageously from 1 / 100 to 1 / 10.

[0396] In a sixth variant, the molar ratio of the chain-end methyl functional group to the secondary amide functional group is from 1 / 5000 to 1 / 50, advantageously from 1 / 2000 to 1 / 100 and very advantageously from 1 / 1000 to 1 / 200.

[0397] Needless to say, as a function of the used single-material object and the exposure it has undergone, one or more functional groups resulting from the oxidation reaction may be present.

[0398] The composition advantageously contains residues of stabilizers selected from phenols, quinones, stilbenequinones and phosphites.

[0399] The recycled polyamide advantageously contains alkyl chain ends having a carbon number (between 1 and 18) greater than that of the unused PA. Advantageously, the alkyl chain end content is from 1 ppm to 0.5%.

[0400] According to another aspect, the invention relates to the use of the composition as defined above for the manufacture of objects, in particular single materials.

[0401] The single material object thus manufactured from a used single material object can itself be recycled at least once, in particular from 1 to 10 times, according to the method of the invention. Description of the Drawings

[0402] Figure 1 Showing in a solvent mixture with an HFIP / CD2Cl2 ratio of 1 / 3 13 The CH2CO area of various secondary amide, primary amide and carboxylic acid functional groups in 13C NMR.

[0403] Top spectrum: PA11 housing of an electronic watch worn on the arm for five years throughout the day, bottom spectrum: PA 11 based on 100% unused material. Examples

[0404] The housings and bracelets of the electronic watches EC1 to EC3 and E11 to EI2 are assembled using screws. The percentages shown are mass percentages. The screws are removed before recycling.

[0405] The composition and its evaluation are shown in Table 1.

[0406]

[0407] PA 11: Homopolyamide 11 having NH2 chain ends of 45 μeq / g and COOH chain ends of 40 μeq / g. The intrinsic viscosity of this polyamide is 1.46.

[0408] PA 12: Homopolyamide 12 having NH2 chain ends of 25 μeq / g and COOH chain ends of 65 μeq / g. The intrinsic viscosity of this polyamide is 1.21.

[0409] PA 6: Homopolyamide 6 having NH2 chain ends of 24 μeq / g and COOH chain ends of 65 μeq / g. The intrinsic viscosity of this polyamide is 1.42.

[0410] PEBA No.1: A PEBA copolymer containing a PA 11 block with a number-average molar mass of 1000 g / mol and a flexible PTMG block with a number-average molar mass of 1000 g / mol, and having a hardness of 40 Shore D. The intrinsic viscosity of this copolymer is 1.35.

[0411] - PEBA No.2: A PEBA copolymer containing a PA 6 block with an average molar mass of 1500 g / mol and a flexible PEG block with a number-average molar mass of 1500 g / mol, and having a hardness of 30 Shore D. The intrinsic viscosity of this copolymer is 1.40.

[0412] TPU No.1: A TPU having a rigid block based on 4,4'-MDI (4,4'-diphenylmethane diisocyanate) and 1,4-BDO (1,4-butanediol) and a flexible polyester block based on adipic acid and butanediol, with a hardness of 85 Shore A.

[0413] The intrinsic viscosity was measured in m-cresol according to Standard ISO 307:2007, but with the solvent changed (using m-cresol instead of sulfuric acid and at a temperature of 20 °C).

[0414] The EC1 and EI1 objects were ground to a size smaller than 30 mm and then compounded in an 18 mm twin-screw extruder at a flow rate of 5 kg / h and a temperature of 250 °C in order to obtain properties obtained during the second life of the material for evaluation.

[0415] Then the granules thus obtained were injection molded using a Battenfeld BA800 CDC press to manufacture ISO 5271A test specimens. The following parameters were applied during injection:

[0416] - Barrel temperature: 240 °C.

[0417] - Nozzle temperature: 260 °C.

[0418] - Mold temperature: 30 °C.

[0419] - Cycle time: 60 seconds.

[0420] The tensile modulus at 23 °C was measured according to Standard ISO 527-1A.

[0421] After conditioning at 23 °C and 50% relative humidity for 15 days, the density at 23 °C was measured according to Standard ISO 1183-1.

[0422] The objects of the present invention provide a composition with a lower density for an equivalent modulus after recycling.

[0423] The above embodiments show that the properties obtained after recycling the objects according to the present invention are better and thus the objects can be recycled to manufacture new high-performance objects.

Claims

1. A single-material object, which comprises at least two components: - At least one first component consisting of a first composition, which composition comprises, relative to the total weight of the first component, at least 30%, notably at least 50%, particularly at least 70%, more particularly at least 90% by weight of at least one long-chain homopolyamide or at least one long-chain copolyamide, Said at least one long-chain homopolyamide and said at least one long-chain copolyamide independently of one another represent repeating units selected from the following: units obtained by polycondensation of at least one C4-C 36 units obtained by polycondensation of at least one C4-C 36 units obtained by polycondensation of lactams and XY units obtained by polycondensation of the following: At least one diamine selected from linear or branched aliphatic diamines, cycloaliphatic diamines and semi-aromatic aliphatic diamines, or mixtures thereof, and At least one dicarboxylic acid selected from: Aliphatic dicarboxylic acids, cycloaliphatic dicarboxylic acids and aromatic dicarboxylic acids, Said diamine and said dicarboxylic acid containing from 4 to 36 carbon atoms, advantageously from 6 to 18 carbon atoms, Said first composition excluding copolyamides bearing amide units (Ba1) and polyether units (Ba2), - At least one second component consisting of a second composition, which composition comprises, relative to the total weight of the second component, at least 30%, notably at least 50%, particularly at least 70%, more particularly at least 90% by weight of a copolyamide bearing amide units (Ba1) and polyether units (Ba2), Said first and second components being capable of at least partially adhering to one another, Said at least one long-chain homopolyamide or at least one long-chain copolyamide of the first composition having a C / N ratio greater than or equal to 8, particularly greater than or equal to 9, notably greater than or equal to 10, and said copolyamide of the second composition having a C / N ratio of units (Ba1) greater than or equal to 6, notably having greater than or equal to 8, particularly greater than or equal to 9, notably greater than or equal to 10, Said object excluding single-layer or multi-layer structures for transporting, distributing or storing fluids.

2. The single-material object according to claim 1, characterized in that, The single-material object is selected from electronic articles, textile articles, optical articles, household electrical articles, cosmetic articles, sports articles, stationery articles, luggage articles, toys, furniture or motor vehicle parts.

3. The single-material object according to claim 1 or 2, characterized in that Only one of the two compositions contains a filler and the other composition does not contain a filler.

4. The single-material object according to claims 1 to 3, characterized in that, At least 10% by weight, particularly at least 30% by weight, of the units of said at least one homopolyamide or said at least one copolyamide constituting the first composition and of the polyamide bearing units (Ba1) of the second composition are identical; particularly, said units are PA11 units.

5. The single-material object according to claims 1 to 4, characterized in that, The copolyamides bearing amide units (Ba1) and polyether units (Ba2) of the first composition and of the second composition contain the same polyamide, particularly PA11.

6. The single-material object according to claims 1 to 4, characterized in that, Said first and second components are selected from the following constituent elements: fabrics, films or textured films, foams, injection-molded parts, extruded parts, 3D printed parts, adhesives, non-wovens, meshes and consolidated thermoplastic composite parts, preferably selected from fabrics, foams, injection-molded parts, 3D printed parts, adhesives, non-wovens, meshes and consolidated thermoplastic composite parts.

7. The single-material object according to claim 6, characterized in that, It comprises at least two different constituent elements as defined in claim 6.

8. The single-material object according to claim 7, wherein It comprises at least three different constituent elements as defined in claim 6.

9. The single-material object according to any one of claims 1 to 8, characterized in that, The first element and the second element are adhered to each other by bonding with a non-polyamide adhesive, and the content of the non-polyamide adhesive ranges from 0.01% to 10% by weight, particularly from 0.1% to 4% by weight, based on the total mass of the object.

10. The single-material object according to any one of claims 1 to 9, characterized in that It comprises at least one third element composed of a third composition, and the third composition comprises: at least one long-chain homopolyamide or at least one long-chain copolyamide or at least one copolyamide having amide units (Ba1) and polyether units (Ba2) or a mixture thereof, and the at least one copolyamide having amide units (Ba1) and polyether units (Ba2) is as defined in claim 1.

11. A method for manufacturing a monolithic object according to any one of claims 1 to 10, comprising steps involving: providing a first element composed of a first composition, the first composition comprising at least 30% by weight, notably at least 50% by weight, particularly at least 70% by weight, more particularly at least 90% by weight of at least one long-chain homopolyamide or at least one long-chain copolyamide as defined in claim 1, based on the total weight of the first element, providing a second element composed of a second composition, the second composition comprising at least 30% by weight, notably at least 50% by weight, particularly at least 70% by weight, more particularly at least 90% by weight of at least one copolyamide having amide units (Ba1) and polyether units (Ba2) as defined in claim 1, based on the total weight of the second element, assembling the elements of the object by means of an adhesive, where appropriate, to form a finished or semi-finished object.

12. A method for recycling an object as defined in any one of claims 1 to 10, comprising steps involving: (a) providing a used object, (b) optionally separating the elements of the object that are not recyclable in the method, (c) optionally cleaning the used object from step (a) or (b), (d) optionally first grinding the used object from step (a) or (b), or the used object from step (c) when cleaning in step (c), to obtain a first ground material, (e) optionally washing the first ground material when not performing the cleaning in step (c), (f) grinding the used object from step (a) and / or (b) and / or (c) and / or (d) and / or (e) so as to obtain a first ground material or a second ground material in the case where the first grinding in step (d) has been performed, (g) heating the ground material from step (f) until it melts, (h) optionally compounding and (i) extruding or injection molding the molten material.

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

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

15. A composition, which comprises by weight: 30% to 100%, advantageously 50% to 99% of recycled polyamide from the object defined in any one of claims 1 to 10, 0 to 70% of virgin polyamide selected from homopolyamides, in particular long-chain homopolyamides, copolyamides, in particular long-chain copolyamides, and PEBA; advantageously, the virgin polyamide is a homopolyamide, in particular a long-chain homopolyamide, 0 to 65% of filler, 0 to 20%, in particular 0.1% to 5% of additives, The sum of the components is equal to 100%, The recycled polyamide has functional groups resulting from an oxidation reaction, which are selected from primary amide functional groups, nitriles, chain-end methyl groups, olefins, formamides, imides, carboxylic acids, and alcohols and mixtures thereof, and the molar ratio of this functional group to the amide functional group is greater than that of the same polyamide constituting the virgin unused object.

16. The composition according to claim 15, characterized in that The molar ratio of the functional group derived from the oxidation reaction to the secondary amide functional group is from 1 / 10000 to 1 / 20.

17. The composition according to claim 15 or 16, characterized in that The molar ratio of the imide functional group to the secondary amide functional group is from 1 / 1000 to 1 / 20, in particular 1 / 500 to 1 / 20, in particular 1 / 200 to 1 / 50.

18. The composition according to any one of claims 15 to 17, characterized in that The molar ratio of the carboxylic acid functional group to the secondary amide functional group is from 1 / 5000 to 1 / 20, and in particular 1 / 3000 to 1 / 50, very advantageously 1 / 500 to 1 / 15.

19. The composition according to any one of claims 15 to 18, characterized in that The molar ratio of the alcohol functional group to the secondary amide functional group is from 1 / 1000 to 1 / 20, advantageously 1 / 1000 to 1 / 25, and very advantageously 1 / 200 to 1 / 50.

20. The composition according to any one of claims 15 to 19, characterized in that The molar ratio of the primary amide functional group to the secondary amide functional group is from 1 / 2000 to 1 / 20, advantageously 1 / 1000 to 1 / 100, and very advantageously 1 / 1000 to 1 / 500.

21. The composition according to any one of claims 15 to 20, characterized in that The molar ratio of the nitrile functional group to the secondary amide functional group is from 1 / 1000 to 1 / 20, advantageously 1 / 500 to 1 / 15, and very advantageously 1 / 100 to 1 / 10.

22. The composition according to any one of claims 15 to 21, characterized in that The molar ratio of the chain-end methyl functional group to the secondary amide functional group is from 1 / 5000 to 1 / 50, advantageously 1 / 2000 to 1 / 100, and very advantageously 1 / 1000 to 1 / 200. Use of the composition according to any one of claims 14 to 22 for the manufacture of an object, in particular a single-material object.

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