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
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/12—Powdering or granulating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
  • B29C64/10—Processes of additive manufacturing
  • B29C64/141—Processes of additive manufacturing using only solid materials
  • B29C64/153—Processes of additive manufacturing using only solid materials using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y50/00—Data acquisition or data processing for additive manufacturing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y70/00—Materials specially adapted for additive manufacturing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y70/00—Materials specially adapted for additive manufacturing
  • B33Y70/10—Composites of different types of material, e.g. mixtures of ceramics and polymers or mixtures of metals and biomaterials
• • 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
  • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
  • C08G69/08—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from amino-carboxylic acids
• • 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
  • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
  • C08G69/26—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from polyamines and polycarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/09—Carboxylic acids; Metal salts thereof; Anhydrides thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/17—Amines; Quaternary ammonium compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
  • C08L77/02—Polyamides derived from omega-amino carboxylic acids or from lactams thereof
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2077/00—Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as moulding material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
  • B29K2105/25—Solid
  • B29K2105/251—Particles, powder or granules
• • 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
  • C08J2377/02—Polyamides derived from omega-amino carboxylic acids or from lactams thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/09—Carboxylic acids; Metal salts thereof; Anhydrides thereof
  • C08K5/092—Polycarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/36—Sulfur-, selenium-, or tellurium-containing compounds
  • C08K5/37—Thiols
  • C08K5/372—Sulfides, e.g. R-(S)x-R'

Definitions

• the present invention relates to powders of polymers, in particular of polyamides, intended for use in processes for the agglomeration of powders by fusion and which can be recycled several times.
• the technology of agglomeration of polyamide powders is used to manufacture three-dimensional objects by adding or agglomerating powder by melting layer by layer.
• This technology is used in particular to manufacture prototypes and models, in various fields such as automotive, nautical, aeronautics, aerospace, the medical field, textiles, clothing, decoration, etc. housings for electronics, telephony, home automation, IT and lighting, fashion, sport, and industrial tools.
• the agglomeration of powders by fusion is caused by radiation, such as for example a laser beam (also known as laser sintering or laser sintering), infrared radiation, UV radiation, LED-type radiation, or any source of electromagnetic radiation making it possible to melt the powder layer by layer to produce three-dimensional objects.
• a thin layer of polyamide powder is deposited on a horizontal plate maintained in an enclosure heated to a temperature between the crystallization temperature Te and the melting temperature TF of the polyamide powder.
• the laser makes it possible to fuse particles of powder at different points of the layer which crystallize slowly after the passage of the laser according to a geometry corresponding to the object, for example using a computer having in memory the shape of the 3D object and restoring the latter in the form of straightforward 2D.
• the horizontal plate is lowered by a value corresponding to the thickness of a layer of powder (for example between 0.05 and 2 mm and generally of the order of 0.1 mm) then a new layer is deposited.
• the laser fuses powder particles according to a geometry corresponding to this new layer which crystallizes slowly according to a geometry corresponding to the object and so on.
• the procedure is repeated until the entire object has been manufactured.
• the polyamide powder In the case of laser sintering at least 50% of the powder is not targeted by the laser. It is therefore advantageous to be able to reuse, that is to say to recycle, this powder during the next construction (or "run”). For this, the polyamide powder must have retained its initial properties as much as possible: particle size, flowability, color, viscosity, etc.
• 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 molecular mass and therefore the viscosity of the polyamide. Subsequently, the coalescence between powder grains becomes more and more difficult during the successive runs.
• Te crystallization temperature
• certain polyamide powders require the parameters of the sintering device to be modified, in particular to drastically increase the power of the radiation, each time the powder is recycled during successive runs. In addition, a very clear decline in the mechanical properties of the parts obtained as the runs are observed.
• the present invention results from the unexpected demonstration, by the inventors, that the addition of at least one chain limiter in the solid or liquid state, in particular a monoacid, a dicarboxylic acid, a monoamine or a diamine, in a polyamide powder makes it possible to control, in particular to lower, stabilize or eliminate, the increase in the viscosity e ⁇ of the melting temperature of the non-agglomerated polyamide powder which occurs during the cycles, or ru ns, successive of an agglomeration process by fusion. This makes it possible to reuse or recycle the non-agglomerated powder, and to obtain objects with reproducible properties during successive runs.
• at least one chain limiter in the solid or liquid state in particular a monoacid, a dicarboxylic acid, a monoamine or a diamine
• the present invention relates to a polyamide powder intended for use in a powder agglomeration process by fusion, comprising at least one chain limiter.
• the present invention also relates to the use of polyamide powder as defined above, to manufacture objects by agglomeration of said powder by melting.
• the present invention also relates to an object manufacturing process in which a polyamide powder as defined above is agglomerated by melting.
• the present invention also relates to an object manufactured using at least one polyamide powder as defined above.
• the present invention also relates to a process as defined above in which the non-agglomerated polyamide powder is recovered.
• the present invention also relates to the use of a non-agglomerated polyamide powder e ⁇ recovered according to the above process for the manufacture of objects by agglomeration of the powder by fusion.
• the present invention also relates to the use of at least one chain limiter for controlling the increase in viscosity or in the melting point of a polyamide powder intended to be used in a process for manufacturing an object by powder agglomeration. by merger.
• the present invention also relates to the use of at least one chain limiter for improving the recyclability of a polyamide powder intended for use in a powder agglomeration process by fusion.
• the D50 of a powder corresponds to the value of the particle size which divides the population of particles examined in exactly two.
• the D50 is measured according to the ISO 9276 standard - parts 1 to 6: “Representation of data obtained by particle size analysis” or according to the ISO 13319 standard.
• the inherent viscosity in solution is preferably measured according to the method comprising the following steps:
• the melting temperature according to the invention is preferably measured by differential scanning colorimetry (DSC) according to the ISO 1 1357-6 standard, in particular on a DSC Q2000 device (TA Instruments), preferably with an equilibrium at -20 ° C. (temperature change rate 20 ° C / min up to 240 ° C, 20 ° C / min up to - 20 ° C, 20 ° C / min up to 240 ° C).
• DSC differential scanning colorimetry
• the term “reproducible mechanical properties” means mechanical properties, in particular of tensile modulus, elongation at break, and stress at break, which each remain at least greater than 90% of their value. measured for an object of the same shape constructed in 3D printing from fresh powder.
• the percentages expressed are percentages by weight. Unless otherwise stated, the parameters to which it is ⁇ made ⁇ are measured at atmospheric pressure e ⁇ at room temperature (approximately 23 ° C).
• Standard NF EN ISO 1874-1: 201 1 defines a nomenclature of polyamides.
• the term "monomer” in the present description of powders based on polyamides should be taken in the sense of "repeating unit".
• the case where a repeating unit of the polyamide consists of the association of a diacid with a particular diamine is ⁇ . It is considered that it is the association of a diamine e ⁇ of a diacid, that is to say the "diamine-diacid” couple, also called “XY”, in an equimolar amount which corresponds to the monomer. This is explained by the fact that individually the diacid or diamine is only a structural unit, which is not sufficient on its own to form a polymer.
• the chain limiter according to the invention is selected from the group consisting of dicarboxylic acids, mono carboxylic acids, diamines and monoamines, each of which may be linear or cyclic.
• the chain limiter has a melting temperature below 180 ° C.
• the chain-limiting monocarboxylic acid according to the invention preferably has from 2 to 20 carbon atoms.
• a chain-limiting monocarboxylic acid it is possible to cite acetic acid, propionic acid, benzoic acid, stearic acid, lauric acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, hexadecanoic acid, octodecanoic acid, tetradecanoic acid.
• the chain-limiting dicarboxylic acid according to the invention preferably has from 2 to 20 carbon atoms, more preferably from 6 to 10 carbon atoms.
• a chain-limiting dicarboxylic acid according to the invention it is ⁇ possible to cite sebacic acid, adipic acid, azelaic acid, suberic acid, dodecanedicarboxylic acid, butanedioic acid, and ortho-phthalic acid.
• the chain-limiting monoamine according to the invention is a primary amine having 2 to 18 carbon atoms.
• a chain-limiting monoamine according to the invention it is possible to cite 1-aminopentane, 1-aminohexane, l-aminohep ⁇ ane, l-aminooc ⁇ ane, 1-aminononane, 1-aminodecane, 1-aminoundecane, 1-aminododecane, benzylamine, e ⁇ oleylamine.
• the chain-limiting diamine according to the invention has from 4 to 20 carbon atoms.
• a chain-limiting diamine according to the invention it is possible to cite the isomers of bis- (4-aminocyclohexyl) mefhane (BACM), bis- (3-méfhyl-4-aminocyclohexyl) mefhane (BMACM) ), and 2-2-bis- (3-methyl-4-aminocyclohexyl) -propane (BMACP), and para-amino-di-cyclo-hexyl-mefhane (PACM), isophoronediamine (IPDA), 2, 6-bis- (aminomefhyl) -norbornane (BAMN) and piperazine.
• ACBM bis- (4-aminocyclohexyl) mefhane
• BMACM bis- (3-méfhyl-4-aminocyclohexyl) mefhane
• BMACP 2-2
• the chain limiter according to the invention represents from 0.01 to 10%, preferably 0.01 to 5%, preferably from 0.01 to 4%, preferably from 0.01 to 3%, of preferably from 0.01 to 2%, preferably from 0.01 to 1% by mass on the total mass of polyamide powder representing 100%. More preferably, the chain limiter according to the invention represents from 0.01 to 0.5%, from 0.01 to 0.4%, from 0.01 to 0.3%, from 0.01 to 0.2 % by mass on the total mass of polyamide powder representing 100%.
• the chain limiter is preferably in powder form.
• the chain limiter according to the invention is preferably added to the medium comprising the polyamide already formed e ⁇ does not enter into the composition of the polyamide.
• the chain limiter is incorporated into the polyamide powder by any suitable method known to those skilled in the art such as, for example, dry mixing, liquid mixing, aqueous dispersion, mixing by compounding, mixing by diffusion.
• the chain limiter preferably in powder form, is dry mixed with a polyamide powder.
• the reaction between the chain limiters and the polyamide chain end which occurs during the 3D printing process effectively limits the increase in the inherent viscosity of the powder and does not disturb the conditions of the powder. 3D printing.
• the invention thus proposes a powder comprising a chain limifeur which is very easy to use.
• the chain limifier preferably in powder form, is mixed with a powder of polyamide prepolymers having an inherent viscosity of less than or equal to 0.80. The mixture then undergoes a solid phase polycondensation step to obtain a polyamide powder of desired viscosity.
• the solid phase polycondensation step is performed at a temperature above the glass transition temperature and below the melting temperature of the polyamide.
• the solid phase polycondensation is typically carried out in a dryer.
• This embodiment makes it possible to provide a powder ready for use in a 3D printing process, which has several advantages:
• the chain limifier is preferably added after the aforementioned intermediate steps.
• the chain limiters added are either reacted with the chain ends of the polyamide prepolymers during the polycondensation step or will react with the functions available to react on the polyamide chain during 3D printing.
• the loss of the chain stopper materials used is avoided.
• part of the limifier molecules will be integrated into the chain of polyamide, thus losing its ability to limit the elongation of the polyamide chain.
• the chain limiter is mixed with the polyamide prepolymer powder which has previously undergone a water treatment step and / or an acid treatment step.
• the chain stopper preferably has a melting temperature above the glass transition temperature and below the melting temperature of the polyamide.
• the chain limiter according to the invention makes it possible to control, in particular to lower, stabilize or eliminate, the increase in viscosity and / or in the melting temperature of a polyamide powder used in an agglomeration process. by melting but not agglomerated, which allows the powder to be reused in the powder agglomeration process.
• the chain limiter according to the invention allows the recycling or reuse of the non-agglomerated polyamide powder and the production of objects with reproducible properties during successive runs (cycles).
• the polyamide according to the invention can be a homopolyamide, a copolyamide or a mixture thereof.
• the polyamide according to the invention can also be a mixture of polyamide and at least one other polymer, the polyamide forming the matrix and the other polymer (s) forming the dispersed phase.
• the polyamide according to the invention is a condensation product:
• amino acid it is possible to cite alpha-omega amino acids, such as aminocaproic, 7-amino-heptanoic, 11-amino-undecanoic, n-heptyl-11-aminoundecanoic and 12-amino acids -dodecanoic.
• the lactam monomers according to the invention preferably comprise between 3 and 12 carbon atoms on the main cycle and can be substituted.
• a lactam according to the invention it is possible to cite (3, (3- dimethylpropriolactam, ⁇ , ⁇ -dimethylpropriolactam, amylolactam, caprolactam, capryllactam, oenantholactam, 2-pyrrolidone and lauryllactam.
• the diamine forming part of the composition of the polyamide according to the invention is an aliphatic diamine, an aryl dimaine and / or a saturated cyclic diamine having from 6 to 12 carbon atoms.
• a diamine according to the invention it is possible to cite hexamethylenediamine, decanediamine, piperazine, tetramethylene diamine, octamethylene diamine, decamethylene diamine, dodecamethylene diamine, 1, 5 diaminohexane, 2,2,4-trimethyl-1,6-diamino-hexane, polyols diamine, isophorone diamine (I PD), methyl-pentamethylenediamine (MPDM), bis (aminocyclohexyl) methane (BACM), bis ( 3-methyl-4-aminocyclohexyl) methane (BMACM), methaxylyenediamine, bis-p-aminocyclohexy
• the dicarboxylic acid forming part of the composition of the polyamide according to the invention has between 4 and 18 carbon atoms.
• dicarboxylic acid it is possible to cite adipic acid, sebacic acid, azelaic acid, suberic acid, isophthalic acid, butanedioic acid, 1, 4 acid.
• the copolyamide according to the invention results 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 acid. alpha-omega aminocarboxylic of different carbon numbers. It is also possible to cite the copolyamides resulting from the condensation of at least one alpha-omega-aminocarboxylic acid (or one lactam), at least one diamine and at least one dicarboxylic acid.
• the polyamide powder according to the invention comprises at least one polyamide or copolyamide comprising at least one monomer selected from the group consisting of 46, 4T, 54, 59, 510, 512, 513, 514, 516, 518, 536, 6, 64, 69, 610, 612, 613, 614, 616, 618, 636, 6T, 9, 104, 109, 1010, 101 1, 1012, 1013, 1014, 1016, 1018,
• the polyamide according to the invention is selected from the group consisting of PA 6, PA 66, PA 1010, PA 1 1, PA 12, PA 101 1, PA 610, PA612, PA 613 e ⁇ of their mixtures.
• copolyamide it is possible to cite copolymers of caprolacfam e ⁇ of lauryllacfam (PA 6/12), copolymers of caprolacfam, of adipic acid and of hexamefethylene diamine (PA 6/66) , copolymers of caprolacfam, lauryllacfam, adipic acid and hexamethylene diamine (PA 6/12/66), copolymers of caprolactam, lauryllactam, amino-1 1 - undecanoic acid, azelaic acid e ⁇ of hexamethylene diamine (PA 6/69/1 1/12), copolymers of caprolactam, lauryllactam, amino-1 1 -undecanoic acid, adipic acid e ⁇ of hexamethylene diamine (PA 6 / 66/1 1/12), copolymers of lauryllactam, azelaic acid e ⁇ of hexamethylene diamine diamine (
• the mixture of polyamide e ⁇ of at least one other polymer it is in the form of a mixture with a polyamide matrix e ⁇ the other (s) polymer (s) form (s) the phase dispersed.
• this other polymer one can quote polyolefins, polyesters, polycarbonate, PPO (abbreviation of polyphenylene oxide), PPS (abbreviation of polyphenylene sulfide), e ⁇ elastomers such as ether-amide block copolymers (PEBA), thermoplastic polyurethane (TPU), elastomeric polyphenylene ether (PPE).
• mixtures of polyamides are, for example, mixtures of aliphatic polyamides e ⁇ of semi-aroma polyamides e ⁇ mixtures of aliphatic polyamides and e ⁇ of cycloaliphafic polyamides.
• an amorphous polyamide (B) which results mainly from condensation: - itself ⁇ of at least one diamine chosen from cycloaliphatic diamines and aliphatic diamines e ⁇ of at least one diacid selected from cycloaliphatic diacids e ⁇ aliphatic diacids, at least one of these diamine or diacid units being cycloaliphafic ,
• - e ⁇ optionally at least one monomer chosen from alpha-omega-amino carboxylic acids or the possible corresponding lacfames, aliphatic diacids e ⁇ aliphatic diamines,
• an amorphous polyamide (B) which results essentially from the condensation of at least one optionally cycloaliphafic diamine, of at least one aromatic diacid e ⁇ optionally of at least one monomer chosen from: acids alpha-omega amino carboxylic acids, aliphatic diacids, aliphatic diamines,
• 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 the products obtained being, in this particular case, polyetheresteramides.
• the polyamide sequences containing dicarboxylic chain ends originate, for example, from the condensation of alpha-omega-aminocarboxylic acids, lactams or dicarboxylic acids and diamines in the presence of a dicarboxylic acid chain limiter.
• 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 5000 g / mol and preferably between 600 and 1500 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 can also comprise units distributed randomly. These polymers can be prepared by the simultaneous reaction of the polyether and the precursors of the polyamide blocks.
• polyetherdiol 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 such and copolycondensed with polyamide blocks with carboxylic ends, or they are ⁇ aminated to be transformed into polyether diamines and condensed with polyamide blocks with carboxylic ends. They can also be mixed with polyamide precursors and a chain limifeur 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 polyamide powder particles according to the invention have a volume median diameter (D50) of between 5 and 200 miti, more preferably between 10 and 150 miti.
• D50 volume median diameter
• the polyamide powder according to the invention has a difference between the crystallization temperature (Te) and the first heating melting point (TF1) (Te -TF1) greater than 3 ° C.
• This difference advantageously makes it possible to avoid deformation phenomena and to obtain a good geometric definition of the manufactured parts.
• this difference makes it possible to increase the working window with the polyamide powder and to make its use in a sintering process much easier.
• the inherent viscosity in solution of the polyamide powder according to the invention is less than 1.90, preferably less than 1.70, preferably less than 1.60, preferably less than 1.50.
• the inherent viscosity in solution of the polyamide powder according to the invention in particular after a first run in a powder agglomeration process according to the invention, is greater than 1.
• the polyamide powder according to the invention when it is melted, increases in viscosity, to reach a sufficient molecular mass, and to guarantee a solution viscosity of the part of preferably greater than 1.50 so that the part ( 3D object) has acceptable mechanical properties. More preferably, the viscosity of the part is greater than 1.60, preferably greater than 1.70, preferably greater than 1.80, preferably greater than 1.90, preferably greater than 2.
• the powder according to the invention is recyclable at least 3 times, preferably at least 5 times, more preferably at least 10 times.
• the polyamide according to the invention whether it is thirsty or not mixed with at least one other polymer can contain organic or mineral fillers, pigments, antioxidants, in particular combined with a thioether antioxidant, UV stabilizers, plasticizers, colorants, flow agents.
• the polymer powder according to the invention can comprise a thioether antioxidant.
• a thioether antioxidant advantageousously, the addition of such an antioxidant to the polymer powder according to the invention makes it possible to stabilize the color of the powder, in particular its whiteness when it is white, in particular by limiting its yellowing during recycling of the powder. according to the invention.
• the thioether antioxidant according to the invention is preferably selected from the group consisting of dilauryl thiodipropionate (DLTDP), ditridecyl thiodipropionate (DTDTDP), distearyl thiodipropionate (DSTDP), dimyrystil thiodipropionate (DMTDP), pentaerythritol-tetodrakis (3-propellant or 3-laurylthiopropionate), 3,3'-thiodipropionate, alkyl (Cl 2-14) thiopropionate, dilauryl 3,3'-thiodipropionate, ditridecyl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3 '- thiodipropionate, dioctadecyl 3,3'-thiodipropionate, lauryl stearyl 3,3-
• the thioether antioxidant according to the invention is selected from the group consisting of dilauryl thiodipropionate (DLTDP), ditridecyl thiodipropionate (DTDTDP), distearyl thiodipropionate (DSTDP), dimyrystil thiodipropionate (DMTDP), pentaerythritol-tetodrakecyl (3-properythritio-tetodrakis) (3) 3-laurylthiopropionate), and their mixtures. More preferably the antioxidant fhioether according to the invention is DLTDP or penfaeryfhrifol fetrakis (3-dodecylthio propionate).
• Such antioxidants are sold in particular by the Songnox or Adeka companies.
• said at least one thioether antioxidant represents at least 0.1%, preferably 0.1 to 5%, preferably 0.1 to 4%, preferably 0.1 to 3%, preferably 0.1 to 2%, preferably 0.1 to 1% by mass, on the total mass of powder representing 100%.
• the thioether antioxidant as defined above is incorporated into the powder by any suitable method known to those skilled in the art, for example by at least one of the following methods: addition of thioether during the synthesis of polyamide, in particular at the start or at the end of synthesis, by mixing by compounding, during any step of a process for manufacturing powder from said polyamide, in particular by dissolving-precipitating polyamide in a solvent containing thioether, by example dispersed or dissolved in the solvent, or by dry mixing (dry blend) with the polyamide powder according to the invention.
• the chain limiter is mixed with the polyamide powder, and at least one thioether antioxidant, by the dry mixing.
• the thioether is added, with the chain limiter in a polyamide prepolymer powder having an inherent viscosity less than or equal to 0.80, which undergo a solid phase polycondensation step to obtain a polyamide powder. to the desired viscosity.
• the chain limiter is mixed with the polyamide prepolymer powder, and at least one thioether antioxidant, after a water treatment step and / or an acid treatment step.
• the thioether according to the invention is preferably in powder form.
• said thioether antioxidant has a melting point of less than 140 ° C, preferably less than 100 ° C, preferably less than 90 ° C, preferably less than 70 ° C.
• antioxidants other than the thioether antioxidant used according to the invention, mention may be made of phenolic antioxidants intended to fight against thermo-oxidation of polyamides, such as 3,3'-Bis (3,5-di- ⁇ er ⁇ -bu ⁇ yl-4- hydroxyphenyl) -N, N'-hexamethylenedipropionamide sold in particular under the name Palmarole AO.OH .98 by Palmarole, (4,4'-Bu ⁇ ylidenebis (2- ⁇ -bu ⁇ yl-5-methylphenol) sold in particular under the name Lowinox 44B25 by Addivant, Pentaerythritol ⁇ e ⁇ rakis (3- (3, 5-di- ⁇ er ⁇ bu ⁇ yl-4-hydroxyphenyl) propiona ⁇ e) sold in particular under the name Irganox® 1010 by BASF, N, N'-hexane-1,6-diyl
• a powder agglomeration process by fusion is considered synonymous with sintering.
• the powder agglomeration process by fusion according to the invention is preferably a process for manufacturing objects or articles, in particular three-dimensional (3D).
• Fusion is preferably achieved with the aid of radiation or an input of electromagnetic energy.
• the radiation can be chosen from any radiation well known to those skilled in the art. As an example of radiation, it is possible to cite a laser beam, infrared radiation, UV radiation, LED type radiation. Particularly preferably, the fusion is obtained by laser radiation, this is called a laser sintering process (“laser sintering"). Even more preferably, the powder agglomeration process by fusion according to the invention is a selective laser sintering process (“selective laser sintering”), or a process known as “High Speed Sintering” (HSS) or “ Multi-Jet Fusion ”(MJF).
• selective laser sintering selective laser sintering process
• HSS High Speed Sintering
• MTF Multi-Jet Fusion
• the powder agglomeration process by fusion according to the invention is a layer-to-layer process or an additive manufacturing process.
• the powder agglomeration process by fusion comprises the following steps: a. a thin layer of polyamide powder according to the invention (layer 1) is deposited on a horizontal plate maintained in an enclosure heated to a temperature between the crystallization temperature (Te) and the melting temperature (TF) of said powder, b. radiation, in particular laser radiation, allows the agglomeration of the powder particles by melting at different points of the powder layer (layer 1) according to a geometry corresponding to the object to be manufactured, c. the horizontal plate is then lowered by a value corresponding to the thickness of a layer of powder then a new layer of powder is deposited (layer 2), d.
• layer 1 a thin layer of polyamide powder according to the invention
• TF melting temperature
• the radiation in particular the laser radiation, allows the agglomeration of the particles by melting the powder layer (layer 2) according to a geometry corresponding to this new frankness of the object to be manufactured, e. the preceding steps are repeated, thus forming a cycle, until the object is constructed; f. an object surrounded by powder is obtained inside the enclosure; g. after complete cooling, the object is separated from the powder.
• the powder agglomeration process by fusion according to the invention is a 3D printing process.
• the powder agglomeration process by fusion according to the invention can be implemented by a suitable device, in particular a 3D printer.
• a suitable device in particular a 3D printer.
• devices it is possible to cite the sintering devices marketed by EOS, 3D Systems, Aspect, Trump Précision Machinery, Hewlett Packard, Sinferif, Sinfrafec, Sharebot, FormLabs, Sonda Sys, Farsoon, Prodways, Ricoh, Wema ⁇ er3D, VoxelJet, or even Xaar. Mention may more particularly be made of the EOSINT P396 and Formiga PI 00 devices from EOS GmbH.
• the powder reused or recycled according to the invention is the powder which has not been agglomerated, or which has not melted, during the various powder melting cycles necessary to manufacture or construct an object.
• the different cycles form a "run".
• a "run" corresponds to a construction.
• the recycled powder content is at least 50%, preferably at least 60%, more preferably at least 70% by weight, on the total mass of powder used in the machine for each run.
• each run which follows reuses or recycles at least 50%, preferably at least 60%, preferably at least 70%, by mass of powder from the previous run which has not been agglomerated, on the total mass of powder used in the machine for each run.
• the object or article according to the invention is preferably a three-dimensional (3D) object or article, in particular a 3D printing product.
• this object is chosen from a prototype, a part model ("rapid prototyping"), a finished part in small series (“rapid manufacturing”) for the automotive, nautical, aeronautical, aerospace, medical (prostheses, systems) fields. hearing aids, ...), textiles, clothing, fashion, decoration, the field of housings for electronics, telephony, home automation, IT, lighting, sport, and tools industrial.
• the objects according to the invention have:
• the above mechanical properties are preferably all measured according to standard ISO 527-1 B: 2012.
• the inventors studied the aging of the powder according to the invention by reproducing the conditions to which powders for 3D printing are exposed during several printing runs.
• the powder for 3D printing tested consists of 1000 parts by mass of a PA1 1 powder obtained by grinding the polymer resulting from the polycondensation of 1-amino-1-undecanoic acid catalyzed by hypophosphoric acid (H3PO4) (powder 1) or by hypophosphorous acid (H3PO2) (powder 2) and mixed with 2 to 5 parts by mass of a phenolic antioxidant (Irganox 245 (BASF)), 3 to 8 parts by mass of a thioether antioxidant (ADK Stab A0412S (Adeka)), 1 to 3 parts by mass of a flow agent (Cab-O-Sil TS 610 (CABOT)).
• the comparative example consists of 1000 parts by mass of a powder of PA1 1 obtained by grinding the polymer resulting from the polycondensation of amino-1 1-undecanoic acid catalyzed by hypophosphoric acid (H3PO4) (powder 1) or by hypophosphorous acid (H3PO2) (powder 2) and mixed with 3 parts by mass of a phenolic antioxidant (Irganox 245 (BASF)), 5 parts by mass of a thioether antioxidant (ADK Stab A0412S (Adeka)) , 2 parts by mass of a flow agent (Cab-O-Sil TS 610 (CABOT)).
• the antioxidants and the flow agent were added to the prepolymer of PA 1 1, then the mixture is subjected to a solid phase polycondensation step, to give the powder of Example 1 .2.
• the test consists in exposing the polyamide powder to a temperature of 10 to 50 ° C. lower than the melting point TF of the pure polyamide.
• Polyamide powders (comparative example and polyamide powders according to the invention) are placed in glass bottles closed by an aluminum cap pierced with holes. The bottles are placed in an oven (ITEM FGE 140) regulated at 180 ° C, in air, for aging.
• This test simulates the exposure conditions that a powder can undergo in a 3D machine, during 1 run or several runs, depending on the exposure times. The von ⁇ exposure times from 0 to 90 hours.
• the inherent viscosity is measured at 20 ° C., in a 0.5% mass solution in metacresol according to the viscosity measurement method detailed above.
• the melting temperature of the powder is measured by differential scanning colorimetry (DSC) according to the ISOl 1357-6 standard on a DSC Q2000 device (TA Instruments) with an equilibrium at -20 ° C (rate of temperature change 20 ° C / min. up to 240 ° C, 20 ° C / min up to -20 ° C, 20 ° C / min up to 240 ° C).
• DSC differential scanning colorimetry
• Table 1 below includes the viscosity measurements of polyamide powders (comparative example and polyamide powders according to the invention) having an initial viscosity of 1.35.
• Table 2 represents the viscosity measurements of polyamide powders according to the invention having an initial viscosity of 1.10.
• Table 3 represents the measurements of the melting temperature of the polyamide powders according to the invention above having an initial viscosity of 1.10. [Table 31 C. Conclusion
• the aging tests were carried out according to the protocol described in Example 1 (see 1 .2) except that the tests were carried out at 180 ° C. under vacuum.
• the powder for 3D printing tested consists of 1000 parts by mass of a PA1 1 powder and mixed dry (“dry-blend"), with 2 to 5 parts by mass of a phenolic antioxidant (Irganox 245 (BASF) ), 3 to 8 parts by mass of a thioether antioxidant (ADK Stab A0412S (Adeka)), 1 to 3 parts by mass of a flow agent (Cab-O-Sil TS 610 (CABOT)).
• Three samples were formulated comprising 2, 4 and 6 parts by mass of sebacic acid (DC10), and 6 parts by mass of dodecanedioic acid (DC12).

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