Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J11/00—Recovery or working-up of waste materials
  • C08J11/04—Recovery or working-up of waste materials of polymers
  • C08J11/06—Recovery or working-up of waste materials of polymers without chemical reactions
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
  • C08G69/48—Polymers modified by chemical after-treatment
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J11/00—Recovery or working-up of waste materials
  • C08J11/04—Recovery or working-up of waste materials of polymers
  • C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
  • C08J11/18—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material
  • C08J11/22—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic oxygen-containing compounds
  • C08J11/26—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic oxygen-containing compounds containing carboxylic acid groups, their anhydrides or esters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J11/00—Recovery or working-up of waste materials
  • C08J11/04—Recovery or working-up of waste materials of polymers
  • C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
  • C08J11/18—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material
  • C08J11/28—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic compounds containing nitrogen, sulfur or phosphorus
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2377/00—Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2377/00—Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers
  • C08J2377/06—Polyamides derived from polyamines and polycarboxylic acids
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W30/00—Technologies for solid waste management
  • Y02W30/50—Reuse, recycling or recovery technologies
  • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

• TITLE PROCESS FOR TREATING A COMPOSITION BASED ON POLYAMIDES
• the present invention relates to a process for treating a polyamide-based composition intended to be recycled. More particularly, the present invention relates to a method of treating a composition, typically a powder based on unconverted polyamides during the manufacture of an object in 3D printing. The invention also relates to the use of the recycled composition in further industrial processing.
• polyamides have been produced in large quantities and widely used in various fields of the chemical industry for many years. However, some or even a large amount of polyamides used in industrial processing processes are not transformed into final products, and they cannot be reused as such as raw material for a subsequent processing process due to modification of their physical and / or chemical properties. This creates a real problem of waste, whether from an economic or environmental point of view.
• the term “transformation process” is understood to mean any type of industrial transformation of a composition based on polyamides into final products, for example, by extrusion, molding, typically by injection, or even by 3D printing. .
• this wastage problem is commonly observed in the field of 3D printing using a polyamide-based powder as raw material for manufacture, such as, for example, any process for manufacturing parts in volume by adding or agglomerating powder, layer by layer.
• the agglomeration of powders by fusion (hereinafter “sintering”) is caused by radiation, such as for example a laser beam (laser sintering), infra-red radiation, UV radiation, or any source of electromagnetic radiation allowing to melt the powder layer by layer to make three-dimensional objects.
• sintering is caused by radiation, such as for example a laser beam (laser sintering), infra-red radiation, UV radiation, or any source of electromagnetic radiation allowing to melt the powder layer by layer to make three-dimensional objects.
• HSS High Speed Sintering
• MJ F Multi-Jet Fusion
• the manufacture of 3D objects is also done layer by layer, using a polyamide-based powder which is melted in a controlled manner for each layer constituting the 3D object: an absorber is deposited on the layer (by means of example of a liquid ink in the “inkjet process”) before exposure of the layer to electromagnetic radiation (for example infrared) which causes the fusion of the zones containing said absorber.
• electromagnetic radiation for example infrared
• the use of a polyamide-based powder with a molecular mass of the powder in the solid state which is preferably sufficiently low is preferred, which can result in an inherent viscosity. in solution generally less than 1.50, both so that the fusion of the grains does not require too much energy and so that the inter-grain coalescence is sufficient during the passage of the radiation so as to obtain an object as less porous as possible , with good mechanical properties.
• the polyamide-based powder used in a sintering process of the aforementioned type generally comprises more than 90%, or even more than 95% of polyamide by weight of the total powder. It has been observed that during the manufacturing process, a large part of the powder is not used: for example in laser sintering, approximately 85% of the powder is not targeted by the laser. The surrounding powder, that is to say not touched by the radiation, remains several hours above its crystallization temperature Te, which can lead to an increase in the molecular mass and therefore in the inherent viscosity of the powder. polyamide base. As a result, the coalescence between powder grains becomes more difficult for later reuse for 3D construction by employing this powder.
• the starting powder which has not been touched by the radiation at the end of printing can often have a higher molecular weight, that is, an inherent viscosity greater than 1.50 and more often than l. 'order of 1.70 to 2.0.
• the powder is no longer able to produce parts of sufficient mechanical strength by 3D printing technology.
• These powders must be discarded in order to be replaced at least in part by a charge of so-called “fresh” powder, which has not undergone temperature variations during printing.
• the present invention therefore aims to provide a method for treating polyamide-based compositions having a high inherent viscosity, generally following a transformation process, so that they can be reused as raw materials in desired industrial applications. .
• the present invention aims to provide a method for treating a polyamide-based powder not used at the end of a 3D printing process, preferably a 3D printing process by sintering, in order to '' be reused as a raw material for industrial transformations, for example, in an injection molding, extrusion or even 3D printing process.
• the present invention relates to a process for treating a composition (C1) based on polyamides (PA) intended to be recycled, comprising the following successive steps:
• composition (C1) based on polyamides (PA), a polyamide chain cutting agent, and optionally one or more filler (s) and / or additive (s);
• composition (C1) can be all types of industrial compositions based on polyamides, for example powders, granules, filaments, resins, fibers, films, tubes and / or their mixtures.
• a composition based on polyamides is meant a composition with a polyamide matrix, which generally comprises more than 40% polyamide by volume of the total composition.
• the composition (C1) based on polyamides intended to be recycled is a powder based on polyamides, preferably that which is not transformed at the end of a 3D printing process by sintering.
• composition (C1) is a polyamide-based powder, it generally comprises more than 50%, or even more than 60% of polyamide by weight of the total composition.
• the polyamide (PA) of the invention can be chosen from a homopolyamide, a copolyamide, a copolymer containing polyamide blocks and polyether blocks, or mixtures thereof. It can also be a mixture of one or more polyamides and at least one other polymer. The mixtures can be obtained by dry mixing of powders or by grinding the mixture in the form of granules. In the latter case, the polyamide preferably forms the matrix and the other polymer (s) form the dispersed phase.
• composition (C1) has an inherent viscosity greater than or equal to 1.50, preferably greater than or equal to 1. 60.
• composition (C1) is an unprocessed material remaining at the end of a transformation process.
• composition (C2) is less than or equal to 1.50, preferably less than or equal to 1. 40, to 1, 30, to 1, 25, to 1, 20, to 1 , 15, at 1, 10, at 1, 05, or even less than or equal to 1, 00.
• the inherent viscosity of composition (C2) is typically greater than or equal to 0.80.
• the inherent viscosity of composition (C2) can be between 0.80 and 1.50, preferably between 0.90 and 1.40, between 0.90 and 1.30, between 0.90 and 1. 20 (terminals included).
• the inherent viscosity of the composition (C2) recovered (or called “recycled”) is typically reduced by at least 10%, preferably by at least 20%, relative to that of the starting composition (C1).
• the inherent viscosity of the composition (C2) recovered is reduced by 0.30, preferably by 0.50 compared to that of the starting composition (C1).
• composition (C2) recovered is typically in the form of granules.
• the polyamide chain cutting agent of the invention is a chemical agent which can react with the polyamides present in the composition intended to be recycled and which is capable of reducing the inherent viscosity of said composition.
• the inventors have found that the use of the chain cutting agent allows the polyamide chain to be "cut", thereby reducing the inherent viscosity of the polyamide, as well as the inherent viscosity of the polyamide-based composition.
• the present invention thus proposes to use a particular chain-cutting agent to reduce the inherent viscosity of a polyamide-based composition in order to recover a composition which can be used in a subsequent transformation process.
• the chain cutting agent is chosen from water, a carboxylic acid, an amino acid and / or a mixture thereof.
• the chain-cutting agent is in the form of a solid (e.g. powder or granule), or in the form of a liquid (e.g. molten or in the form of an aqueous solution).
• the chain cutting agent is a carboxylic acid.
• the carboxylic acid can be chosen from monocarboxylic acids, dicarboxylic acids, metal salts of mono- or dicarboxylic acids.
• the carboxylic acid is chosen from adipic acid, azelaic acid, suberic acid, sebacic acid, dodecanedioic acid, and / or a mixture thereof.
• the carboxylic acid is adipic acid.
• 0.1 to 2%, preferably 0.2 to 1.8%, for example 0.2 to 1.0%, of 0, is provided. 2 to 0.8%, by mass of carboxylic acid, relative to the mass of composition (C1).
• the carboxylic acid used as the chain-cutting agent is to be distinguished from those which may be present in composition (C1) as residues of polymerization monomers, which are present in trace form, generally at less than 0, 1% in the composition.
• the chain cutting agent is an amino acid.
• the amino acid can be chosen from aminocaproic acids, amino-7-heptanoic, amino-11-undecanoic, amino-12-dodecanoic, and / or a mixture thereof.
• an amino acid is chosen which corresponds to the unit of monomer of the polyamide (PA) in the composition (C1) to be recycled.
• PA polyamide
• an 11-amino-undecanoic can be chosen in the recycling process of a polyamide 11.
• a 12-amino-dodecanoic acid can be selected in a recycling process of a polyamide 12.
• the amino acid is 11-amino-undecanoic.
• the amino acid is 12-amino-dodecanoic.
• step (i) 0.1 to 10%, preferably 0.2 to 8%, for example 1 to 7% by mass of amino acid, relative to the mass, is provided. of the composition (C1).
• the amino acid used as the chain-cutting agent is to be distinguished from those which may be present in composition (C1) such as residues of polymerization monomers, which are present in trace form, generally at less than 0.1% in the composition.
• the chain cutting agent is water.
• step (i) 0.05 to 10%, preferably 0.1 to 8%, for example 0.5 to 7% by mass of water, relative to to the mass of the composition (C1).
• the inherent viscosity targeted for the composition recovered at the end of the transformation process can be easily achieved, in particular by adjusting the amount of the chain-cutting agent used. Typically, if during the process the final inherent viscosity achieved is too high, the amount of chain cutter can be increased in increments of 10% (in relative value) without changing the amount of starting composition, until the amount of chain cutter is obtained. inherent viscosity targeted. Otherwise, if the final viscosity is too low, the amount of chain cutter can be reduced in increments of 10% (in relative value) without changing the amount of starting composition, until the target inherent viscosity is obtained.
• one or more fillers and / or additives can be introduced in step (i) of the process of the present invention.
• These fillers and / or additives make it possible to improve the properties of the polyamide depending on its end use and / or to improve the mechanical properties (for example, Young's modulus, elongation at break, impact resistance) or even aesthetic properties such as color.
• the fillers and / or the additives may already be present in the composition (C1) based on polyamides (PA) intended to be recycled, or else, be added in the composition (C2) after the recovery step. (iii).
• the conditions applied in mixing step (ii) are chosen to allow intimate mixing of the compounds in the molten state.
• composition (C1) can comprise one or more polyamides.
• the temperature applied is at least 5 ° C higher, preferably at least 10 ° C higher than the melting temperature of the polyamide.
• the temperature applied is at least 5 ° C. higher, preferably at least 10 ° C. higher than the highest melting temperature of the polyamides.
• the temperature applied in step (ii) is greater than 200 ° C and less than 330 ° C, preferably greater than 220 ° C and less than 320 ° C, for example between 220 ⁇ and 310 ° C, or for example between 230 ° C and 300 ° C.
• the recovery step (iii) can be carried out using methods known to those skilled in the art.
• the recovery step consists of an extrusion step, a step of cooling the composition in the molten state using a cooling liquid containing water, a step of cutting the composition in the form of granules, and a step of separating the coolant and the cooled composition.
• the cutting step can be performed during the cooling step, or after the cooling step, and before the separating step or after the separating step.
• the process of the invention can be a batch process.
• the process of the invention may preferably be a continuous process.
• the residence time of the mixture in step (ii) is typically equal to or less than 10 minutes, especially less than 5 minutes. , or less than 3 minutes or even less.
• the process of the present invention thus makes it possible to recycle a composition based on polyamides in a simple and very efficient manner: the composition intended to be recycled is treated in less than 10 minutes, or even in less than 5 minutes, or 3 minutes or even less so that a reusable polyamide-based composition can be recovered as a raw material.
• the present invention thus provides a simple and effective solution for recycling a composition based on polyamides, in particular such a composition in powder form such as that not transformed at the end of a 3D printing process using a powder (eg. sintering 3D printing process).
• the subject of the present invention is an installation for carrying out the method of the invention.
• the method of the invention is carried out by means of a so-called reactive extruder (with external heating), known to those skilled in the art.
• the process is carried out in an extruder comprising two co-rotating feed screws.
• the present invention relates to a composition based on recycled polyamides, capable of being obtained by the process of the invention, generally having an inherent viscosity less than or equal to 1.50, preferably less than or equal. at 1, 40, at 1, 30, at 1, 25, at 1, 20, at 1, 15, at
• composition recycled at the end of the transformation process can be in the form of granules, in the form of powder, filament, resin, fiber, films or tube, preferably in the form of granules.
• One of the advantages of the present invention is that the composition recycled at the end of the process according to the invention can be used directly and / or easily transformed with technologies known to those skilled in the art.
• the invention relates to the use of the recycled polyamide-based composition, preferably in the form of granules, in a transformation process.
• the invention relates to a transformation process employing a composition based on recycled polyamides, preferably in the form of granules, as a raw material.
• the invention also relates to an article manufactured according to a transformation process using a composition based on recycled polyamides as defined above.
• composition recovered at the end of the process according to the invention can be used in coatings, paints, compositions. anticorrosion, paper additives, electrophoresis gels, multi-layered composite materials, the packaging industry, toys, textiles, automotive and / or electronics.
• the present invention also relates to the use of the recycled composition based on polyamides obtained according to the method of the invention in a 3D printing process, preferably a 3D printing process by sintering.
• the 3D printing process is a process using a powder.
• the 3D printing process can be other types of 3D printing process other than those using powder.
• techniques such as FDM (Fused Deposition Modeling), or FFF (Fused Filament Fabrication), using filaments.
• the present invention also relates to an article of manufacture obtained by the 3D printing processes as mentioned above.
• This manufactured article can be chosen from prototypes, models and parts, in particular in the automotive, nautical, aeronautical, aerospace, medical fields (prostheses, hearing systems, cellular tissues, etc.), design, housings for electronics, telephony, home automation, IT, lighting, sports, industrial tools.
• the invention will now be described in more detail.
• the inherent viscosity in solution of the polyamide-based composition is preferably measured according to ISO standard 307: 2007 modified in that the solvent is m-cresol rather than sulfuric acid, in that the concentration is 0.5% by mass and in that the temperature is 20 ° C.
• composition (C1) based on the polyamides intended to be recycled of the present invention can be in all its forms in any industrial application, such as powder, granule, filament, resin, fiber, films, tube.
• Composition (C1) preferably has an inherent viscosity greater than or equal to 1.50, preferably greater than or equal to 1. 60.
• the polyamide can be aliphatic, semi-aromatic and cycloaliphatic.
• the polyamide can be chosen from a homopolyamide, a copolyamide, a copolymer containing polyamide blocks and polyether blocks, and their mixtures.
• polyamide means the condensation products:
• amino acid monomers such as aminocaproic, 7-amino-heptanoic, 11-amino-undecanoic and 12-amino-dodecanoic acids of one or more lactam monomers such as caprolactam, oenantholactam and lauryllactam;
• diamine monomers such as hexamethylenediamine, decanediamine, dodecamethylenediamine, metaxylylenediamine, bis-p-aminocyclohexylmethane and trimethylhexamethylenediamine with diacids such as isophthalic, terephthalic, terephthalic and terephthalic acids suberic, sebacic, dodecanedioic and tetradecanedioic.
• diamine monomers such as hexamethylenediamine, decanediamine, dodecamethylenediamine, metaxylylenediamine, bis-p-aminocyclohexylmethane and trimethylhexamethylenediamine with diacids such as isophthalic, terephthalic, terephthalic and terephthalic acids suberic, sebacic, dodecanedioic and tetradecanedioic.
• the polyamide can be a copolyamide. Mention may be made of the copolyamides resulting from the condensation of at least two different monomers, for example of at least two different alpha omega aminocarboxylic acids or of two different lactams or of a lactam and of an alpha omega aminocarboxylic acid of a number of different carbon. Mention may also be made of the copolyamides resulting from the condensation of at least one alpha omega-aminocarboxylic acid (or a lactam), at least one diamine and at least one dicarboxylic acid.
• copolyamides resulting from the condensation of an aliphatic diamine with an aliphatic dicarboxylic acid and at least one other monomer chosen from aliphatic diamines different from the previous one and aliphatic dicacids different from the previous one.
• polyamides in this description of polyamides should be taken in the sense of "repeating unit".
• a repeating unit of the polyamide consists of the association of a diacid with a diamine is particular. It is considered that it is the association of a diamine and a diacid, that is to say the “diaminediacid” couple, also called “XY”, in an equimolar amount which corresponds to the monomer. This is because, individually, the diacid or diamine is only a structural unit, which is not enough on its own to form a polymer.
• diamine X By way of example of diamine X, mention may be made of aliphatic diamines having from 6 to 12 atoms, the diamine X possibly also being saturated aryl and / or cyclic. By way of examples, mention may be made of hexamethylenediamine, piperazine, tetramethylene diamine, octamethylene diamine, decamethylene diamine, dodecamethylene diamine, 1, 5 diaminohexane, 2,2,4-triméthyM, 6-diamino - hexane, polyols diamine, isophorone diamine (IPD), methyl pentamethylenediamine (MPMD), bis (aminocyclohexyl) methane (BACM), bis (3-methyl-4 aminocyclohexyl) methane (BMACM), metaxylyenediamine, bis-p aminocyclohexylmethane and trimethylhexamethylene diamine.
• IPD isophorone di
• a diacid (or dicarboxylic acid) Y By way of example of a diacid (or dicarboxylic acid) Y, mention may be made of acids having between 4 and 18 carbon atoms. Mention may be made, for example, of adipic acid, sebacic acid, azelaic acid, suberic acid, dodecanedioic acid, tetradecanedioic acid, isophthalic acid, butanedioic acid, acid 1 , 4 cyclohexyldicarboxylic, terephthalic acid, sodium or lithium salt of 5-sulfo-isophthalic acid, dimerized fatty acids (these dimerized fatty acids have a dimer content of at least 98% and are preferably hydrogenated).
• lactam or amino acid monomers are said to be of “Z” type:
• lactams By way of example of lactams, mention may be made of those having from 3 to 12 carbon atoms on the main cycle and which may be substituted. Mention may be made, for example, of b, b-dimethylpropriolactam, a, a-dimethylpropriolactam, amylolactam, caprolactam, capryllactam, oenantholactam, 2-pyrrolidone and lauryllactam.
• alpha-omega amino acids such as aminocaproic, 7-amino-heptanoic, 11-amino-undecanoic, n-heptyl-11-aminoundecanoic and 12-amino-dodecanoic acids.
• the polyamide (PA) according to the invention comprises at least one polyamide or a polyamide block chosen from polyamides and copolyamides comprising at least one of the following monomers: 46, 4T, 54,
• the polyamides (PA) comprise at least one polyamide chosen from polyamides and copolyamides comprising at least one of the following XY or Z monomers: 59, 510, 512, 514, 6, 69, 610, 612, 614, 109, 1010, 1012, 1014, 10T, 11, 12, 129, 1210, 1212, 1214, 12T, MXD6, MXD10, MXD12, MXD14, and mixtures thereof; in particular chosen from PA 11, PA 12, PA 1010, PA 6, PA 612 and mixtures thereof.
• copolyamides As examples of copolyamides, mention may be made of PA 6/12, PA 6/66, PA 6/12/66, PA 6/69/11 / 12, PA 6/66/11 / 12, PA 69 / 12, PA 11/1 OT.
• Copolymers containing polyamide blocks and polyether blocks result from the copolycondensation of polyamide blocks with reactive ends with polyether blocks with reactive ends, such as, among others:
• Polyamide sequences having dicarboxylic chain ends with polyoxyalkylene sequences having diamine chain ends obtained by cyanoethylation and hydrogenation of aliphatic alpha-omega dihydroxylated polyoxyalkylene sequences called polyetherdiols.
• Polyamide blocks having dicarboxylic chain ends with polyetherdiols are advantageously used.
• the polyamide blocks containing dicarboxylic chain ends originate, for example, from the condensation of amino acids, lactams or dicarboxylic acids and diamines in the presence of a dicarboxylic acid chain limiter. Amino acids, lactams, diacids and diamines are those described above.
• the polyether can be, for example, a polytetramethylene glycol (PTMG).
• PTMG polytetramethylene glycol
• PTHF polytetrahydrofuran
• the molar mass in number of the polyamide blocks is between 300 and 15000 and preferably between 600 and 5000 g / mol.
• the molar mass of the polyether blocks is between 100 and 6000 and preferably between 200 and 3000 g / mol.
• Polymers containing polyamide blocks and polyether blocks are generally prepared by the simultaneous reaction of the polyether and of the precursors of the polyamide blocks. For example, one can react polyetherdiol, a lactam (or an alpha-omega amino acid) and a chain-limiting diacid in the presence of a little water. A polymer is obtained essentially having polyether blocks, polyamide blocks of very variable length, but also the various reactants having reacted randomly which are distributed randomly along the polymer chain.
• the polyetherdiol blocks are either used as they are and copolycondensed with polyamide blocks having carboxylic ends, or they are aminated in order to be transformed into polyether diamines and condensed with polyamide blocks having carboxylic ends. They can also be mixed with polyamide precursors and a chain limiter to make polymers containing polyamide blocks and polyether blocks having units distributed in a statistical manner.
• the ratio of the amount of polyamide block and polyether block copolymer to the amount of polyamide is advantageously between 1/99 and 15/85 by weight.
• the mixture of polyamide and of at least one other polymer it is in the form of a mixture with a polyamide matrix and the other (s) polymer (s) form (s) the dispersed phase.
• this other polymer mention may be made of polyolefins, polyesters, polycarbonate, PPO (short for polyphenylene oxide), PPS (short for polyphenylene sulfide), elastomers.
• the polyamide whether or not it is in admixture with at least one other polymer, can contain fillers, pigments, antioxidants and UV inhibitors.
• the polyamide-based composition (C1) intended to be recycled is in divided form such as powder or granules.
• the polyamide-based composition (C1) is a polyamide-based powder intended for 3D printing, in particular in a sintering process.
• the polyamide is preferably obtained from hydrolytic polycondensation.
• Hydrolytic polycondensation is induced by water at high temperature.
• the hydrolytic polycondensation of lactams consists of opening the lactam with water and then heating under pressure to polymerize.
• a catalyst such as phosphoric acid can also be employed in the hydrolytic process.
• the composition (C1) intended to be recycled can comprise fillers.
• these fillers are in powder or granule form.
• These fillers may already be present in composition (C1) before the treatment process according to the invention or be added during the treatment process according to the invention, to provide the mechanical properties (for example modulus, elongation at break, resistance impact) to the composition recovered at the end of the process.
• powdered fillers mention may be made of carbonated mineral fillers, in particular calcium carbonate, magnesium carbonate, dolomite, calcite, barium sulfate, calcium sulfate, dolomite, aluminum hydrate. , wollastonite, montmorillonite, zeolite, perlite, nanofillers (fillers of the order of a nanometer) such as nanoclays or carbon nanotubes, glass fibers, carbon fibers.
• composition (C1) intended to be recycled can also comprise additives.
• additives Mention may be made, as examples of additives, of flow agents (eg silica), dyes, pigments for coloring, T1O2, pigments for infrared absorption, anti-fire additives, antioxidants, stabilizers. to light, UV stabilizers, plasticizers, anti-shock agents, antistatic agents, flame retardants, and mixtures thereof.
• these additives can be in powder or granule form.
• any device for mixing, kneading or extruding plastics in the molten state known to those skilled in the art can be used.
• the mixing device can be one of the tools mentioned above or their combination, such as for example a co-mixer associated with a return single-screw, a co-rotating twin-screw associated with a gear pump, a reactor connected to an extruder, etc.
• the extrusion tool is generally configured to identify a polymer melting zone, a mixing and reaction zone between the species present and an expansion / degassing zone to remove volatile compounds. These different zones can be materialized by the configuration of the tool screw, the use of a restriction zone or the coupling of tools between them.
• the device can also be equipped with a filtration system, preferably continuous, and a rod or underwater granulation system suitable for the rheology of the polyamide.
• any suitable mixer such as a Brabender or Plastograph W50EHT mixer, composed of a motor, a mixing chamber, two rotors rotating in opposite directions at different speeds to ensure the mixing of the mixture.
• molten material molten material, a thermocouple, and data acquisition.
• the mixing step (ii) of the process according to the invention is carried out in a co-rotating twin-screw extruder, which has many advantages.
• the geared corotating twin-screw extruder makes it possible to carry out the process continuously and with a low residence time.
• the products are less subject to thermo-oxidation, and in particular are less likely to undergo yellowing.
• the recovery step (iii) generally consists of an extrusion step, a step of cooling the composition in the molten state using a cooling liquid containing water, a cutting step of the composition in the form of granules, and a step of separating the coolant from the cooled composition.
• the extrusion step can be carried out in a conventional manner, in particular through a die.
• the die is generally placed at the outlet of the reactor containing the mixture, or at the outlet of a transfer line supplied with the molten composition using a pump, or at the outlet of a mixing device capable of generating a pressure. above atmospheric pressure, usually an extruder.
• a material is generally obtained in the form of rods or ribbons, or directly in the form of granules in the case for example of a flooded head cut as explained later in the description.
• the cooling step consists in cooling the material obtained after extrusion, by contact with a cooling liquid containing water. It can for example comprise an alcohol such as ethanol, isopropanol, butanol.
• coolant only includes water.
• Suitable cooling devices for such a step are known to those skilled in the art, for example, a water spray device located near the die plate device, a bath or a water stream located. near or in contact with the device of the die plate into which the extruded material is introduced.
• the cutting step can be carried out in suitable devices known to those skilled in the art, for example a milling system with teeth, a system comprising knives and a knife holder.
• the device generally comprises a motor for driving the cutter or the knife holder.
• the cutting device is usually rotary.
• the cutting step is performed after the cooling step and the step of separating the coolant.
• the cooling liquid generally water
• the rods or ribbons of the composition then the rods or ribbons are cut “dry”.
• the separation can be carried out, for example, by removing the rods or ribbons from the bath by a drive device.
• the coolant can be removed by using gravity, or by sucking the liquid through a grid or other perforated device on which the rods or ribbons circulate. These devices are known to those skilled in the art.
• the cutting and cooling steps start simultaneously.
• the two steps are advantageously carried out using a cutting device arranged immediately at the exit of the die.
• a cutting device is known to those skilled in the art. It includes at least one cutting device which faces the die plate through which the polymer is extruded, and a cooling device.
• the cutting device generally includes knives, a knife holder, and a motor for driving the knife holder.
• the knife holder is usually rotatable.
• the cooling device may consist of a device for spraying or circulating coolant located near the device of the die plate. This is the case with “head cut” granulators known to those skilled in the art.
• the cutting device and the die plate can also be placed in a chamber filled with cooling liquid, in this case it is a “flooded-head cut” granulator.
• the cooling liquid is generally in circulation and it ensures the cooling and the transport of the granules of compositions formed at the level of the cutting device to a separator, where the separation step is carried out.
• the separation can be carried out using a centrifuge which separates the cooling liquid and the granules, or for example using a cycloning device.
• the process of the invention can be followed by a grinding step to obtain the composition (C2) in the form of granules, scales or coarse powders.
• the method according to the invention comprises a grinding step where the composition (C2) is ground to obtain a composition in the form of granules, scales or coarse powders.
• the grinding step can be carried out in a counter-rotating pin mill (pin mill), a hammer mill (hammer mill) or in a whirl mill.
• the method can further comprise a sieving step.
• the sieving can be carried out on a sieve.
• the process can include a selection step to obtain the desired particle size profile.
• the powders can be dispersed by a selection wheel and carried by classifying air. Dust entrained in the air is fed through a support wheel and discharged through a first outlet. The coarse product is rejected by a classification wheel and transported to a second outlet.
• the selector may have several successive wheels working in parallel.
• the composition (C2) is ground, sieved and / or selected to obtain a powder with a median diameter by volume (D50) in the range from 5 to 200 ⁇ m, preferably in the form of a D50 powder. in the range of 10 to 150 ⁇ m.
• D50 median diameter by volume
• These powders can be used as raw material in a 3D printing process using powders (eg 3D printing by sintering).
• an inherent viscosity of less than 1.50 can easily be achieved by employing the chain cutting agent.
• the tests were carried out under the same conditions for a period of 10 minutes. The results were measured (Table 2). A drop in viscosity is observed after 3 minutes as observed in Table 1 and then a rise in viscosity in the cases of Examples 2 to 6 and a regular drop for Example 7.

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• Chemical & Material Sciences (AREA)
• Polymers & Plastics (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Organic Chemistry (AREA)
• Sustainable Development (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• Processes Of Treating Macromolecular Substances (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
• Polyamides (AREA)

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• 2020
  • 2020-02-10 FR FR2001292A patent/FR3107059B1/fr active Active
• 2021
  • 2021-02-09 JP JP2022548439A patent/JP2023513252A/ja active Pending
  • 2021-02-09 US US17/798,411 patent/US20230093134A1/en active Pending
  • 2021-02-09 CN CN202180024383.4A patent/CN115315461A/zh active Pending
  • 2021-02-09 WO PCT/FR2021/050233 patent/WO2021160963A1/fr unknown
  • 2021-02-09 EP EP21709071.1A patent/EP4103637A1/de active Pending
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