Polyaryletherketone(s) based powder for the manufacture of ductile objects.

Abstract

The invention relates to a powder comprising particles made of a composition including at least one polyaryletherketone and at least one flexible thermoplastic polymer. The elastic modulus of the flexible thermoplastic polymer is at least twice that of the polyaryletherketone. The polyaryletherketone forms a matrix in which the flexible thermoplastic polymer is dispersed. The powder particles have a volume-weighted particle size distribution with a median diameter d50 strictly less than 500 µm. The invention also relates to a method for manufacturing the powder, as well as uses thereof and articles derived therefrom. Figure for the abstract: Figure 1

Description

Title of the invention: Powder based on polyaryletherketone(s) for the manufacture of ductile objects. Technical field

[0001] The invention relates to the field of polyaryletherketones.

[0002] More particularly, the invention relates to a powder based on polyaryl-therketone(s) for the manufacture of ductile objects, in particular for the manufacture of objects by a method of constructing layer-by-layer objects by sintering caused by electromagnetic radiation(s). Prior art

[0003] Polyaryletherketones (PAEKs) are well-known high-performance technical polymers. They can be used for applications requiring high temperatures and / or mechanical or even chemical constraints. They can also be used for applications requiring excellent fire resistance and low emissions of smoke or toxic gases. Finally, they have good biocompatibility. These polymers are found in fields as varied as aeronautics and space, offshore drilling, automotive, railway, marine, wind power, sports, construction, electronics and even medical implants.

[0004] Notwithstanding these advantageous properties, it is sometimes necessary to formulate polyaryletherketones in order to meet specific specifications. Thus, greater flexibility may be sought to accommodate new modes of use and placement of parts, with greater flexibility. In particular, more ductile polyaryletherketone formulations may be sought, i.e., those exhibiting greater deformation at break and / or exhibiting a lower tensile / flexural elastic modulus and / or higher impact strength, compared to an unformulated PAEK.

[0005] For example, compositions consisting of polyetheretherketone (PEEK) and polyoctenylene are known from US 2009 / 0292073.

[0006] Also known from US 2005 / 004326 A1 are compositions consisting of polyether-retherketone (PEEK) and polysiloxane.

[0007] It is further known from US 2010 / 0147548 A1 compositions consisting of a mixture of (PEEK) and polysiloxane / polyetherimide block copolymer. More specifically, non-delaminating mixtures of PEEK and comprising from 10% to 25% by weight of polysiloxane / polyetherimide block copolymer, comprising from 20% to 30% by weight of polysiloxane, could be manufactured (see in particular table 2 of the patent document).

[0008] Also known from EP 0 323 142 A1 are compositions consisting of a mixture of PEEK, polyetherimide and polysiloxane / polyetherimide block copolymer.

[0009] Also known from US 2019 / 0055390 A1 are compositions consisting of a mixture of PEEK and: i) copolymer composed of repeating units derived from tetrafluoroethylene and propylene or ii) copolymer composed of repeating units derived from hexafluoropropylene and vinylidene.

[0010] Finally, EP 3 749 714 A1 discloses compositions consisting of a mixture of PEKK, a polysiloxane / polyetherimide block copolymer and a polysiloxane. Although the patent document provides for the use of this composition in powder form, no embodiment has been detailed. It is only indicated that such a powder can be obtained according to a standard grinding process. However, as explained below, the existing grinding processes, which already prove to be complex to implement for pure polyaryletherketone compositions, prove in fact to be impossible to implement for more ductile compositions.

[0011] This is notably the reason why none of the aforementioned patents implement means of producing powder. All the mixtures are obtained by compounding, a method which aims to obtain a homogeneous granule of the chosen formulation. These granules are then used for shaping the final object by different processes, in particular extrusion or injection.

[0012] The methods commonly used for manufacturing powders based on polyaryletherketone(s) are grinding methods which all have in common the fact that the material to be ground is sufficiently brittle to be able to be ground.

[0013] For example, it is known from US2009280263 A1 to grind coarse particles of polyetheretherketone under cryogenic conditions. Indeed, the reduction in temperature makes the material more brittle. This process proves ineffective for granules of ductile composition based on polyaryletherketone(s).

[0014] It is also known from EP2776224 to grind coarse particles of polyetherketoneketone at room temperature from particles having a sufficiently low packed density, and therefore incidentally a sufficiently high porosity. Granules of ductile composition based on polyaryletherketone(s) have too high a density to be used in the grinding process at room temperature. Furthermore, it is currently not known how to obtain coarse particles having a sufficiently low density of ductile composition based on polyaryletherketone(s).

[0015] Finally, it is known from WO21069833 to grind coarse particles of polyetherketoneketone comprising a talc-type filler, thus making the coarse particles more brittle. However, the addition of such a filler has the effect of increasing the elastic modulus of the composition and therefore has an effect antagonistic to that sought. in the present invention.

[0016] Thus, none of the aforementioned grinding methods is suitable for providing fine powders, that is to say in particular powders having a volume-weighted particle size distribution with a median diameter strictly less than 500 μm, from ductile compositions based on polyaryletherketone(s).

[0017] There is nevertheless currently a need to provide such powders of ductile composition for methods of manufacturing articles using compositions in powder form. An example of a method, which is particularly detailed later in the present application, is a method of constructing layer-by-layer objects by sintering caused by electromagnetic radiation(s). Other examples of methods requiring a powder composition are coating, for example of metals, from a powder, powder compression molding or powder compression-transfer molding. Goals

[0018] The objective of the invention is to propose a process for obtaining a fine powder of ductile composition based on polyaryletherketone(s), as well as the powder as such, the latter having never been able to be implemented in the prior art.

[0019] The invention also aims, at least according to certain embodiments, to propose a powder and its manufacturing method, the powder being suitable for use in a method of constructing layer-by-layer objects by sintering caused by electromagnetic radiation(s).

[0020] The invention also aims, at least according to certain embodiments, to propose a powder and its manufacturing method, the powder being suitable for use in a coating method from a powder, powder compression molding or even powder compression-transfer molding.

[0021] The invention also aims, at least according to certain embodiments, to provide a powder having a high density.

[0022] The invention also aims, at least according to certain embodiments, to provide a powder having good flowability.

[0023] The invention also aims, at least according to certain embodiments, to provide an at least partially crystallized powder.

[0024] Finally, the invention aims to provide an object having better ductility and / or better impact resistance, compared to objects obtained from non-formulated polyaryletherketone(s), in particular from polyaryletherketone(s) alone. Summary of the invention

[0025] The invention relates to a powder comprising particles consisting of a com position comprising at least one polyaryletherketone and at least one flexible thermoplastic polymer not being a polyaryletherketone. The elastic modulus of said at least one flexible thermoplastic polymer is at least two times lower than that of said at least one polyaryletherketone, as measured according to ISO 527-2: 2012, at 23°C, on a type 1BA test piece obtained by injection molding, with a crosshead speed of 1 mm / min. Said polyaryletherketone forming a matrix in which said flexible thermoplastic polymer is dispersed. Finally, the particles consisting of the composition described above have a volume-weighted particle size distribution, as measured by laser diffraction, according to ISO 13320: 2009, with a median diameter d50 strictly less than 500 pm, and preferably less than or equal to 300 pm.

[0026] The inventors have, unexpectedly, succeeded in manufacturing a powder comprising particles of a composition in which at least one flexible thermoplastic polymer is dispersed in a matrix comprising at least one polyaryletherketone, which had never been possible before by the various grinding techniques usually used.

[0027] This was achievable thanks to the implementation of the manufacturing method according to the invention comprising:

[0028] - a step of providing, in the molten state, a composition comprising the flexible thermoplastic polymer(s) dispersed in the polymer matrix comprising the polyaryletherketone(s);

[0029] - a step of spraying said composition in the molten state, to form droplets of molten composition;

[0030] - a step of cooling the droplets of molten composition to form solid particles; and,

[0031] - optionally one or more heat treatment steps.

[0032] The inventors have here surprisingly noted that this melt spraying process could be implemented without any particular difficulty with a mixture of polymers to obtain particles consisting of a dispersion of one polymer in the other.

[0033] According to certain embodiments, the flexible thermoplastic polymer may have an elastic modulus less than or equal to 1.5 GPa, as measured at 23°C according to ISO 527-1:2019, on a type 1BA test piece obtained by injection molding.

[0034] According to certain embodiments, the flexible thermoplastic polymer(s) may be chosen from the list consisting of: a linear polyene, a polysiloxane, a polysiloxane block copolymer, a fluoroelastomer comprising at least one repeating unit derived from: tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride and chlorotrifluoroethylene, and the mixture of these polymers.

[0035] The fluorinated elastomer may in particular be a copolymer consisting essentially of, or consisting of: a repeating unit derived from tetrafluoroethylene and a repeating unit derived from the monomer of chemical formula CF2=C(F)(R),

[0036] in which R represents: a -CF3 group or an -ORf group, where Rf is a C1-5 perfluoroalkyl; and,

[0037] preferably said fluorinated elastomer may consist essentially, or consist, of a repeating unit derived from tetrafluoroethylene and a repeating unit derived from hexafluoropropylene.

[0038] The polysiloxane block copolymer may in particular be a copolymer in which the polysiloxane blocks are mono- or di-substituted preferably by C1 to C12 alkyl groups, and / or phenyl groups substituted or not by one or more functional groups; and the blocks of units different from the polysiloxanes may preferably be polyetherimide, polyaryletherketone, poly-arylethersulfone, poly(phenylene sulfide), polyarylamideimide, polyphenylene, polybenzimidazole and / or polycarbonate blocks.

[0039] According to certain embodiments, the flexible thermoplastic polymer(s) may represent in total from 5% to 40%, and preferably from 7% to 25%, by weight relative to the total weight of flexible thermoplastic polymer(s) and poly-aryletherketone(s) of the composition.

[0040] According to certain embodiments, the total weight of polyaryletherketone(s) and flexible thermoplastic polymer(s) may represent at least 85%, or at least 90%, or at least 92.5%, or at least 95%, or at least 97.5%, or at least 98%, or at least 98.5%, or at least 99% or at least 99.5%, or 100%, relative to the total weight of the composition.

[0041] According to certain embodiments, the composition may consist of: a polyaryletherketone, a flexible thermoplastic polymer, optionally a polymer other than the polyaryletherketone and the flexible thermoplastic polymer miscible with the polyaryletherketone, and optionally one or more functional additives.

[0042] According to certain embodiments, the particles of the powder may have a volume-weighted particle size distribution, as measured by laser diffraction, according to ISO 13320:2009, with a median diameter d50 ranging from 40 to 140 micrometers, preferably ranging from 50 to 120 micrometers, and more preferably ranging from 60 to 110 micrometers.

[0043] According to certain embodiments, the powder may have a particularly advantageous packed density and / or flowability.

[0044] It may in particular have a packed density greater than or equal to 500 kg / m3, as measured according to standard ISO 1068:1975.

[0045] It may in particular have a flowability less than or equal to 10 seconds, preferably potentially less than or equal to 7 seconds, and extremely preferably less than or equal to 5 seconds, as measured according to method “A” of standard ISO 6186:1998, the powder not otherwise having a flow agent.

[0046] According to certain embodiments, in particular when the method is implemented without an additional heat treatment step, the powder may be in amorphous form.

[0047] According to certain other embodiments, in particular when the method is implemented with at least one heat treatment step, the powder may be in crystallized form.

[0048] It may in particular have a crystallinity rate greater than or equal to 10%, and preferably greater than or equal to 15%, and more preferably greater than or equal to 15%, by weight relative to the total weight of polymers in the composition, as measured by X-ray diffraction.

[0049] According to certain embodiments, said at least one polyaryletherketone is a poly-etherketoneketone, preferably essentially consisting of, and more preferably consisting of: a terephthalic unit and, where appropriate, an isophthalic unit, the terephthalic unit (T) having the chemical formula:

[0050] [Chem.l]

[0051] the isophthalic unit (I) having the chemical formula:

[0052] [Chem.2] OO

[0053] with a molar ratio T:I ranging from 0:100 to 85:15.

[0054] The invention also relates to the use of such a powder in a process for constructing layer-by-layer objects by sintering caused by electromagnetic radiation, in a process for coating from powder, powder compression molding or even powder compression-transfer molding.

[0055] The invention finally relates to an object based on polyaryletherketone(s) obtained by one of the aforementioned manufacturing processes, i.e. processes requiring the use of material in powder form. The invention relates in particular to an object obtained by a process for constructing layer-by-layer objects by sintering caused by a electromagnetic radiation.

[0056] The object according to the invention has mechanical properties which could not be obtained previously, the person skilled in the art having been unable to use until now a powder comprising at least one flexible thermoplastic polymer dispersed in a matrix of polyaryletherketone(s).

[0057] According to certain embodiments, the object may have an elastic modulus strictly less than 4 GPa, as measured on a type 1BA test piece at 23°C according to the ISO 527-1:2019 standard.

[0058] According to certain embodiments, the object may have a Charpy impact strength greater than or equal to 5 kJ / m2, preferably greater than or equal to 6 kJ / m2, preferably greater than or equal to 7 kJ / m2, preferably greater than or equal to 8 kJ / m2, and extremely preferably greater than or equal to 9 kJ / m2, for a type A notched bar according to standard ISO 179:2010. Figures

[0059] The invention will be better understood with regard to the following detailed description of non-limiting embodiments and the following Figures:

[0060] [Fig. 1] schematically represents a device for implementing a method of constructing a three-dimensional object layer-by-layer by sintering in which the powder according to the invention can be used.

[0061] [Fig.2] schematically represents a melt spraying device. Detailed description of the invention Definitions

[0062] The term “thermoplastic polymer” means a polymer

[0063] which becomes less viscous, or more liquid, or liquid when heated sufficiently and which reversibly retains its thermoplasticity. Thermoplastic polymers are generally contrasted with thermosetting polymers which transform irreversibly into an insoluble and non-formable polymer network when hot.

[0064] The term “homopolymer” is understood to mean a polymer consisting of a single repeating unit.

[0065] The term "copolymer" means a polymer resulting from the copolymerization of at least two types of chemically different monomers, called comonomers. A copolymer is therefore formed from at least two repeating units resulting from different monomers. It can also be formed from three or more repeating units resulting from different monomers.

[0066] The copolymer may have a homogeneous structure, in particular of the statistical, alternating or random type, or a heterogeneous structure, in particular of the block type.

[0067] In particular, the term "block copolymer" or "block copolymer" is understood to mean copolymers in the aforementioned sense, in which at least two distinct homopolymer blocks are covalently linked. The length of the blocks may be variable. The blocks may be composed of 1 to 1000, preferably 1 to 100, and in particular 1 to 50 repeating units, respectively. The link between the two homopolymer blocks may be: a simple covalent bond or, an intermediate non-repeating unit called a junction block.

[0068] The term "essentially consisting of unit(s)" is understood to mean that the unit(s) represent(s) a molar proportion of 95% to 99.9% relative to the total number of moles of repeating units in the polymer.

[0069] The term "consisting of unit(s)" is understood to mean that 171st unit(s) represent(s) a molar proportion of at least 99.9%, in particular 100%, in the polymer relative to the total number of moles of repeating units in the polymer.

[0070] The term "polymer blend" is understood to mean a macroscopically homogeneous polymer composition. The term includes in particular such compositions composed of phases immiscible with each other and dispersed on a micrometric or submicronic scale.

[0071] The term "dispersion" is understood to mean a composition comprising several phases. In the mixture according to the invention, the polyaryletherketone forms the continuous phase, or matrix, and the flexible thermoplastic polymer the dispersed phase, generally in the form of nodules. The nodules preferably have an average size less than or equal to 5 micrometers and more preferably less than or equal to 2 micrometers.

[0072] The size of the flexible thermoplastic polymer nodules within the composition, in particular within the matrix based on polyaryletherketone(s), is evaluated by microscopic analysis and digital processing of a cross-section of an object that can be manufactured by a process using powder, in particular a process for constructing layer-by-layer objects by sintering caused by electromagnetic radiation(s). A scanning electron microscope (SEM) can be used. The image obtained can be binarized, which makes it possible to determine the average size and the maximum size of the nodules.

[0073] The term "melting temperature" is understood to mean the temperature at which an at least partially crystalline polymer passes into the viscous liquid state, as measured by differential scanning calorimetry (DSC) according to standard NF EN ISO 11 357-3:2018 in the second heating, using a heating rate of 20°C / min.

[0074] The term "glass transition temperature" is understood to mean the temperature at which an at least partially amorphous polymer changes from a rubbery state to a glassy state, or vice versa, as measured by differential scanning calorimetry. (DSC) according to standard NF EN ISO 11 357-2:2020 in second heating, using a heating rate of 20°C / min.

[0075] Melting and glass transition temperatures are expressed in degrees Celsius (°C).

[0076] The term “crystallinity rate” is understood to mean the crystallinity rate as calculated from wide angle X-ray scattering (WAXS) measurements, on a Nano-inXider® type device with the following conditions:

[0077] - Wavelength: main Kal line of copper (1.54 Angstroms).

[0078] - Generator power: 50 kV - 0.6 mA.

[0079] - Observation mode: transmission.

[0080] - Counting time: 10 minutes.

[0081] - Temperature: 25°C

[0082] A spectrum of the scattered intensity as a function of the diffraction angle is thus obtained. This spectrum makes it possible to identify the presence of crystals, when peaks are visible on the spectrum in addition to the amorphous halo. In the spectrum, the area of ​​the crystalline peaks (denoted A) and the area of ​​the amorphous halo (denoted AH) can be measured. The proportion (by mass) in the crystalline phase is estimated by the ratio (A) / (A+AH). The crystallinity rates in the present invention are expressed as the mass proportion of crystalline polymer(s) relative to the total weight of polymers in the composition.

[0083] The term "amorphous" is understood to mean that the composition has a crystallinity level of 7% or less, preferably 5% or less, and most preferably 3% or less. In some embodiments, the "amorphous" composition may have a crystallinity level of about 0%.

[0084] The term "crystallized polymer" means that the polymer is not amorphous. The polymer then has a crystallinity rate strictly greater than 7%.

[0085] The term "viscosity" is understood to mean the viscosity as measured at 380°C and at 1 Hz under an inert atmosphere (N2), using an "Anton Paar, MCR 302" oscillatory rheometer, in plane / plane geometry.

[0086] The term "modulus of elasticity in tension", or more simply "elastic modulus", is understood to mean the slope of the stress-strain curve o(e) in the interval between the two strains Ei = 0.05% and e2 = 0.25%, as defined in ISO 527-1:2019. The elastic modulus is expressed here in gigapascals (GPa). The slope is preferably measured by a linear regression method.

[0087] Although the elastic modulus is here determined by a mechanical tensile stress, it would not be outside the scope of the invention if the measurement were made from other types of stress, for example in bending or compression.

[0088] For commercial components, elastic moduli are often available on the supplier's product sheets. In the absence of available or predictable data, Tensile elastic modulus measurements can be carried out at 23°C, on a 1BA type specimen with a crosshead speed of 1 mm / min. The actual measurement of the elastic modulus corresponds to the average of five tests carried out consecutively. These tests can, for example, be carried out using an MTS 810® device, marketed by MTS Systems Corporation, equipped with a mechanical extensometer.

[0089] With regard to the characterization of the elastic modulus in tension of the composition of the powder and / or one of its constituents considered in isolation, the 1BA type test pieces are manufactured by injection-molding according to the ASTM D3641-15 standard. The injection / molding conditions are chosen according to one of the following criteria to be considered in the order indicated: conditions imposed by a standard related to the material, indications given by the supplier, or failing that the best available information concerning the polymer or a related polymer.

[0090] With regard to the characterization of the elastic modulus of an object that can be manufactured by a process using powder, the 1BA type specimens are manufactured according to said process. For example, 1BA type specimens can be manufactured by a process for building layer-by-layer objects by sintering caused by electromagnetic radiation(s).

[0091] The term "powder" is understood to mean a fractionated state of matter, generally in the form of very small particles, generally of the order of a hundred micrometers or less. The term "powdery" is understood to mean a composition which is overall in the form of a powder.

[0092] The particle size distribution can be measured by laser diffraction according to ISO 13320:2009, for example on a Malvem Mastersizer 2000® diffractometer. The rules for representing results of a particle size distribution are given by ISO 9276-parts 1 to 6. “d50” means the value of the diameter of the powder particles so that the cumulative function of the particle diameter distribution, weighted by the volume, is equal to 50%. Similarly, the terms “d10” and “d90” mean respectively the corresponding diameters so that the cumulative function of the particle diameters, weighted by the volume, is equal to 10%, and respectively, to 90%.

[0093] "Packed density" means the powder density value measured according to ISO 1068:1975. It can be measured on a STAV 2003 packing volume meter equipped with a 250ml test tube after 2500 pulses. It is expressed in kilograms per cubic meter (kg / m3).

[0094] The term "flowability" means the ability of a powder to flow freely in a regular and constant manner in the form of individual particles. Flowability is measured here according to the so-called "A" method of ISO 6186:1998, with a funnel having an opening of diameter equal to 25 mm, through which the powdered composition can flow. No antistatic agent is otherwise added to the composition. The flowability is measured in seconds (s).

[0095] The term "Charpy impact strength", or more simply "impact strength", is understood to mean the impact strength of bars of size 80*10*4 mm3 notched type A, as measured according to standard ISO 179:2010. The actual measurement corresponds to the average of 3 tests carried out consecutively. A notch (V-shaped with a notch bottom radius of 0.25 + / - 0.05 mm) can be implemented on a device specially designed for this purpose (Automatic Notchvis Plus, marketed by the company Ceast). The bars are then left to rest for 24 hours. The impact strength measurement can be carried out on a Zwick 5102 impact testing machine.

[0096] The singular forms “a” and “the” applied to the composition constituents, such as polyaryletherketone or the flexible thermoplastic polymer, or to a property of these constituents, mean by default “at least one” and respectively “said at least one”. The singular forms nevertheless include, without it being necessary to recall it each time, the embodiments where “a” means “a single one” and “the” means “the only one”.

[0097] Throughout the ranges of values ​​set forth in this application, the limits are included unless otherwise stated. Polyaryletherketone

[0098] A polyaryletherketone (PAEK) comprises the following formula units:

[0099] (-Ar-X-) and (-Ar^Y-),

[0100] in which:

[0101] - Ar and An each denote a divalent aromatic radical;

[0102] - Ar and An may preferably be chosen from 1,3-phenylene, 1,4-phenylene, 3,3'-divalent 1,1'-biphenylene, 3,4'-divalent 1,1'-biphenyl, 1,4-naphthylene, 1,5-naphthylene and 2,6-naphthylene

[0103] - X denotes an electron-withdrawing group; it may preferably be chosen from: carbonyl group and sulfonyl group,

[0104] - Y denotes a group chosen from an oxygen atom, a sulfur atom, a alkylene group, such as -(CH)2- and isopropylidene.

[0105] In these X and Y units, at least 50%, preferably at least 70% and more particularly at least 80% of the X groups are a carbonyl group, and at least 50%, preferably at least 70% and more particularly at least 80% of the Y groups represent an oxygen atom.

[0106] According to a preferred embodiment, 100% of the X groups denote a group carbonyl and 100% of the Y groups represent an oxygen atom.

[0107] Advantageously, the PAEK(s) may be chosen from:

[0108] - a polyether-ketone-ketone, also called PEKK; a PEKK comprises a / unit(s) of formula: -Ph-O-Ph-C(O)-Ph-C(O)-;

[0109] - a polyether-ether-ketone, also called PEEK; a PEEK comprises one or more motif(s) of formula: -Ph-O-Ph-O-Ph-C(O)-;

[0110] - a poly-ether-ketone, also called PEK; a PEK comprises one or more units of formula: -Ph-O-Ph-C(O)-;

[0111] - a poly-ether-ether-ketone-ketone, also called PEEKK; a PEEKK comprises one or more units of formula: -Ph-O-Ph-O-Ph-C(O)- Ph-C(O)-;

[0112] - a polyether-ether-ether-ketone, also called PEEEK; a PEEEK comprises one or more units of formula: -Ph-O-Ph-O-Ph-O- Ph-C(O)-;

[0113] - a poly-ether-diphenyl-ether-ketone also called PEDEK; a PEDEK comprises one or more units of formula: a PEDEK comprises one or more units of formula -Ph-O-Ph-Ph-O-Ph-C(O)-;

[0114] - their mixtures; and,

[0115] - copolymers comprising at least two of the above-mentioned units,

[0116] in which: Ph represents a phenylene group and -C(O)- a group carbonyl, each of the phenylenes being able independently to be of ortho (1-2), meta (1-3) or para (1-4) type, preferentially being of meta or para type.

[0117] Furthermore, defects, end groups and / or monomers may be incorporated in very small amounts into the polymers as described in the list above, without having an impact on their performance.

[0118] Preferably, in the embodiments where the polyaryletherketone is a copolymer, the latter has a homogeneous structure, in particular of the statistical type.

[0119] According to certain embodiments, the PAEK is a polyetherketoneketone essentially consisting of, and preferentially consisting of: a terephthalic repeating unit and, where appropriate, an isophthalic repeating unit, the terephthalic repeating unit (“T unit”) having the formula:

[0120] [Chem.3] (i);

[0121] the isophthalic unit (“unit I”) having the formula:

[0122] [Chem.4] OO (II).

[0123] The mass proportion of T units relative to the sum of the T and I units may vary from 0% to 85%. The mass proportion of T units relative to the sum of the T and I units may in particular be from 0% to 5%; or from 5 to 10%; or from 10 to 15%; or from 15 to 20%; or from 15 to 20%; or from 20 to 25%; or from 25 to 30%; or from 30 to 35%; or from 35 to 40%; or from 40 to 45%; or from 45 to 50%; or from 50 to 55%; or from 55 to 60%; or from 60 to 65%; or from 65 to 70%, or from 70 to 75%, or from 75% to 80%, or from 80% to 85%. The choice of the molar proportion of T units relative to the sum of T and I units is one of the factors that allows the crystallization rate properties of polyether-ketone-ketones to be adjusted. A given molar proportion of T units relative to the sum of T and I units can be obtained by adjusting the respective concentrations of the reactants during polymerization, in a manner known per se.

[0124] For use of the powder in a method for constructing layer-by-layer objects by sintering caused by electromagnetic radiation, the mass proportion of T patterns relative to the sum of the T and I patterns is preferably from 0% to 25% or from 45% to 75%, and more preferably from 0% to 15% or from 55% to 65%. The mass proportion of T patterns relative to the sum of the T and I patterns may in particular be approximately 0% or approximately 60%.

[0125] Such polyaryletherketones are commercially available under the name Kepstan® from the company Arkema.

[0126] According to certain embodiments, the PAEK may be a homopolymer essentially consisting of, or even made up of, a repeating unit having the formula:

[0127] [Chem.5] (III) •

[0128] Such polyaryletherketones are commercially available under the name KetaSpire® from Solvay, under the name VestaKeep® from Evonik and PEEK Victrex® from Victrex.

[0129] According to certain embodiments, the PAEK may be a copolymer essentially consisting of, or even consisting of, a repeating unit having the formula (III) and a repeating unit having the formula:

[0130] [Chem.6]

[0131] The molar proportion of unit (III) relative to the sum of units (III) and (IV) can range from 0% to 99%, preferably from 0% to 95%.

[0132] According to certain embodiments, the PAEK may be a copolymer essentially consisting of, or even consisting of, a repeating unit having the formula (III) and a repeating unit having the formula:

[0133] [Chem.7] (V).

[0134] The molar proportion of unit (III) relative to the sum of units (III) and (V) can range from 0% to 99%, preferably from 0% to 95%.

[0135] The melting temperature of PAEK is preferably greater than 280°C, and very particularly greater than 300°C.

[0136] The glass transition temperature of PAEK is preferably between 100 and 250°C, preferably between 120 and 200°C, and very particularly between 140 and 180°C.

[0137] Advantageously, the PAEK has a viscosity, measured at 380°C and 1 Hz, greater than 100 Pa-s, preferably greater than 200 Pa-s and more preferably greater than 300 Pa-s. The viscosity of the PAEK is generally not greater than 1500 Pa-s. The viscosity of the PAEK may in particular be from 300 Pa-s to 600 Pa-s, or from 600 Pa-s to 800 Pa-s, or from 800 Pa-s to 1000 Pa-s, or from 1000 Pa-s to 1200 Pa-s, or from 1200 Pa-s to 1500 Pa-s.

[0138] According to certain embodiments, the composition comprises at least two PAEKs. The composition may in particular comprise a copolymer consisting essentially of units consisting essentially of, or consisting of repeating units of formulae (I) and (II), or (III) and (IV) or else (III) and (V) which represents more than 50%, preferably more than 60%, in particular more than 70%, more preferably more than 80% and in particular more than 90% by mass of the polyaryletherketone component, including the limit. The remaining 10 to 50% by mass may be constituted by other polymers belonging to the PAEK family, for example the homopolymer consisting of the repetition unit (III).

[0139] According to some embodiments, the composition comprises a single type of PAEK.

[0140] Thermoplastic polymer providing ductility to the composition

[0141] The thermoplastic polymer providing ductility to the composition, or "flexible thermoplastic polymer", is not a polyaryletherketone. It has an elastic modulus half that of polyaryletherketone.

[0142] According to preferred embodiments, the elastic modulus of the flexible thermoplastic polymer may be less than or equal to 1.5 GPa. The low value of the elastic modulus has no other limit than that imposed by the very chemical nature of the thermoplastic polymer used. For thermoplastic polymers currently available on the market, the value of the elastic modulus is generally not less than 10 MPa.

[0143] According to certain embodiments, the elastic modulus of the flexible thermoplastic polymer may be less than or equal to 1 GPa, or even less than or equal to 750 MPa.

[0144] According to certain embodiments, the elastic modulus of the flexible thermoplastic polymer may be greater than or equal to 50 MPa, or even less than or equal to 250 MPa.

[0145] According to certain embodiments, the elastic modulus of the flexible thermoplastic polymer may be from 50 MPa to 1000 MPa, or from 250 MPa to 750 MPa.

[0146] According to certain embodiments, the flexible thermoplastic polymer may be chosen from the list consisting of: a linear polyene, a polysiloxane, a polysiloxane block copolymer, a fluoroelastomer comprising at least one repeating unit derived from tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride and chlorotrifluoroethylene, and their mixture.

[0147] According to certain embodiments, said at least one flexible thermoplastic polymer may represent from 5% to 45% by weight relative to the total weight of said flexible thermoplastic polymer(s) and polyaryletherketone(s) of the composition.

[0148] Said at least one flexible thermoplastic polymer may in particular represent from 5% to 10%, or from 10% to 15%, or from 15% to 20%, or from 20% to 25%, or from 25% to 30%, or from 30% to 35%, or from 35% to 40%, or from 40% to 45% by weight relative to the total weight of said flexible thermoplastic polymer(s) and polyaryletherketone(s) of the composition.

[0149] According to advantageous embodiments, said at least one thermoplastic polymer may represent from 7% to 25% by weight relative to the total weight of said flexible thermoplastic polymer(s) and polyaryletherketone(s) of the composition.

[0150] It is known to those skilled in the art that below a certain proportion of flexible thermoplastic polymer, the contribution of said polymer to the ductility of the composition is low. Furthermore, beyond a certain proportion of polymer flexible thermoplastic the composition tends to lose the excellent thermal resistance and / or chemical resistance properties conferred by PAEK. In addition, inter-polymer adhesion problems may arise (delamination) due to insufficient compatibility of PAEK with the flexible thermoplastic polymer. The person skilled in the art would therefore be led in a manner known per se to use a greater or lesser proportion of flexible thermoplastic polymer, taking into account the expected effect and the compatibility phenomenon.

[0151] The viscosity at 380°C and at 1 Hz of the polyaryletherketone and that of the flexible thermoplastic polymer are sufficiently close to facilitate the dispersion of the flexible thermoplastic polymer in the polyaryletherketone matrix.

[0152] According to certain embodiments, the maximum viscosity ratio between the polyaryletherketone and the flexible thermoplastic polymer is from 0.3 to 3. Preferably, this ratio is greater than or equal to 0.5. It may in particular be greater than or equal to 0.7.

[0153] Preferably, this ratio is less than or equal to 2. It may in particular be less than or equal to 1.5.

[0154] According to certain embodiments, the flexible thermoplastic polymer may be a linear polyene. It is preferably chosen from the list consisting of: poly(3-methyloctenylene), poly(3-methyldecenylene), or a copolymer consisting essentially of, or consisting of, a repeating unit having the chemical formula:

[0155] [Chem.8] (VI),

[0156] in which n is an integer ranging from 3 to 10.

[0157] The linear polyene may in particular be chosen from the list consisting of polypen-tenylene, polyhexenylene, polyheptenylene, polyoctenylene, polynonenylene, polydecenylene, polyundecenylene, polydodecenylene, or a mixture thereof. According to particular embodiments, the linear polyene is a polyoctenylene.

[0158] The linear polyene may represent from 5% to 45% by weight relative to the total weight of said flexible thermoplastic polymer(s) and polyaryletherketone(s) of the composition. The linear polyene may in particular represent 25% or less, preferably 15% or less by weight relative to the total weight of said flexible thermoplastic polymer(s) and polyaryletherketone(s) of the composition. According to the embodiments where the linear polyene is the only flexible thermoplastic polymer, it may in particular represent from 5% to 15% by weight relative to the total weight of said flexible thermoplastic polymer(s) and polyaryletherketone(s) of the composition.

[0159] According to certain embodiments, the flexible thermoplastic polymer may be a fluoroelastomer comprising at least one repeating unit derived from tetrafluoro- roethylene (TFE), hexafluoropropylene (HFP), vinylidene fluoride (VDF) and chlorotrifluoroethylene (CTFE).

[0160] Preferably, the fluorinated elastomer may be a copolymer essentially constituted, or constituted, of repeating units derived from HFP and VDF or else a copolymer essentially constituted, or constituted of a repeating unit derived from TFE and at least one repeating unit derived from propylene, HFP or else a perfluoro(alkyl vinyl ether).

[0161] In particular, the fluorinated elastomer may consist essentially of, and preferably of: a repeating unit derived from TFE and a repeating unit derived from the monomer of chemical formula:

[0162] CF2=CF-R (VII),

[0163] in which R represents: a CF3 group or an ORi group, where Ri is a C1-5 perfluoroalkyl. Preferably, the compound of formula (VII) may be chosen from the group consisting of hexafluoropropylene, perfluoro (methyl vinyl ether), perfluoro (ethyl vinyl ether), and perfluoro (propyl vinyl ether). More preferably, the compound of formula (VII) may be chosen from the group consisting of hexafluoropropylene and perfluoro (propyl vinyl ether).

[0164] According to certain preferred embodiments, the units derived from TFE may represent from 80% to 99.5 mol% relative to the total number of moles of units derived from TFE and the monomer of formula (VII). The repeating unit derived from TFE may in particular represent more than 85 mol%, or more than 87 mol%, or more than 93 mol% relative to the total number of moles of units derived from TFE and the monomer of formula (VII).

[0165] According to certain particular embodiments, the flexible thermoplastic polymer is a copolymer essentially consisting of, or consisting of, repeating units derived from TFE and HFP comprising from 7% to 15% mol of TFE relative to the total number of moles of units derived from TFE and HFP. Examples of such commercially available fluoropolymers are the polymers of the NEOFLON™ FEP range marketed by the company DAIKIN, or of the Teflon® FEP range marketed by the company Dupont, or of the 3M™Dyneon™ Fluoroplastic FEP range marketed by the company 3M.

[0166] The fluorinated elastomer may represent from 10% to 40%, and preferably from 15% to 25% by weight relative to the total weight of said flexible thermoplastic polymer(s) and polyaryletherketone(s) of the composition.

[0167] According to certain embodiments, the thermoplastic polymer may be a polysiloxane block copolymer.

[0168] The polysiloxane blocks may be mono- or di-substituted by C1 to C12, preferably C1 to C6, and very particularly C1 to C4 alkyl groups and / or phenyl groups. Preferably, the alkyl groups are methyl groups. Preferably, the polysiloxane units present in the polysiloxane block copolymer are poly(dimethylsiloxane) (PDMS) units.

[0169] The alkyl or phenyl groups of the polysiloxane block may also be substituted by one or more functional groups such as epoxy, alkoxy, in particular methoxy, amine, ketone, thioether, halogen, nitrile, nitro, sulfone, phosphoryl, imino or thioester. These functional groups may also be located at the end of the chain of the polysiloxane block copolymer. Preferably, however, the polysiloxane block does not comprise functional groups. Furthermore, the alkyl or phenyl groups of the polysiloxane block may be substituted by one or more carbocyclic, aryl, heteroaryl, alkyl, alkenyl, bicyclic or tricyclic groups.

[0170] The polysiloxane block copolymer also comprises blocks of units different from the polysiloxanes. These may in particular be polyetherimide, poly(aryletherketone), poly(arylethersulfone), poly(phenylene sulfide), poly(arylamideimide), poly(phenylene), poly(benzhnidazole) and / or polycarbonate blocks. Preferably, the polysiloxane block copolymer also comprises polyaryletherketone or polyetherimide blocks. The advantage of these blocks is that they are highly compatible with the polyaryletherketone(s) of the composition and therefore allow the incorporation of a high quantity of flexible thermoplastic polymer into the composition.

[0171] The polyaryletherketone blocks may be chosen from the same list as that of the polyaryletherketones used as a constituent of the composition. According to advantageous embodiments, the polyaryletherketone blocks may be of the same chemical composition as that of the polyaryletherketones used as a constituent of the composition.

[0172] Preferably, the polyetherimide blocks comprise, are essentially made up of, or are made up of a repeating unit having the chemical formula:

[0173] [Chem.9]

[0174] in which A represents: -O- or a group of Formula -OZO-, where the divalent groups -O- and -OZO- are in position 3,3', 3,4' or 4,4' of the benzene radicals to which they are linked, and

[0175] where Z can be chosen from the list consisting of:

[0176] [Chem. 10]

[0177]

[0178]

[0179] [Chem. 13]

[0181] [Chem. 15]

[0183]

[0184] (XVII),

[0185] in which Q is a divalent group chosen from the group consisting of: -O-, -S-, -C(O)-, -SO2-, -SO-, -CyH2y- (y being an integer between 0 and 20) and the halogenated derivatives of the latter;

[0186] in which B represents an aromatic hydrocarbon group having 6 to 20 carbon atoms or one of its halogenated derivatives, a linear or branched alkylene chain having 2 to 20 carbon atoms, a cycloalkylene

[0187] having 3 to 20 carbon atoms, or a divalent group of formula (XIII).

[0188] The polysiloxane block copolymer may have a siloxane content of 10 to 70% by weight, preferably 15 to 60% by weight, and more preferably 20 to 50% by weight relative to the weight of the copolymer.

[0189] The polysiloxane block copolymer may represent from 5% to 20%, and preferably from 7% to 15% by weight relative to the total weight of said at least one thermoplastic and at least one polyaryletherketone of the composition.

[0190] Such polysiloxane block copolymers are commercially available. Thus, Sabic sells PELPDMS block copolymers under the name Siltem®. Furthermore, Idemitsu Kosan sells a polycarbonate-PDMS copolymer under the name Tarflon® Neo.

[0191] According to certain embodiments, the flexible thermoplastic polymer may be a polysiloxane. The polysiloxane may be mono- or di-substituted with C1-C12, preferably C1-C6, and most preferably C1-C4, alkyl groups and / or phenyl groups. Preferably, the alkyl groups are methyl groups. The alkyl or phenyl groups of the polysiloxane may be substituted with one or more functional groups such as epoxy, alkoxy, especially methoxy, amine, ketone, thioether, halogen, nitrile, nitro, sulfone, phosphoryl, imino or thioester.

[0192] Preferably, however, the polysiloxane does not comprise functional groups. Furthermore, the alkyl or phenyl groups of the polysiloxane may be substituted by one or more carbocyclic, aryl, heteroaryl, alkyl, alkenyl, bicyclic or tricyclic groups.

[0193] Preferably, the polysiloxane may be a poly(dimethylsiloxane) (PDMS).

[0194] The polysiloxane can represent from 1% to 25% by weight relative to the total weight of said flexible thermoplastic polymer(s) and polyaryletherketone(s) of the composition.

[0195] According to certain embodiments, the polysiloxane may represent 2% or more, or 3% or more, or 4% or more, or 5% or more by weight relative to the total weight of said flexible thermoplastic polymer(s) and polyaryletherketone(s) of the composition. Since the polysiloxane has very low compatibility with polyaryletherketones, it may represent 20% or less, preferably 15% or less and more preferably 13% or less by weight relative to the total weight of said flexible thermoplastic polymer(s) and polyaryletherketone(s) of the composition.

[0196] According to certain embodiments, said at least one flexible thermoplastic polymer of the composition is a mixture of a polysiloxane block copolymer, in particular a block copolymer further comprising poly-aryletherketone or polyetherimide blocks, and a polysiloxane. Other optional components of the composition

[0197] According to preferred embodiments, the composition may comprise at least 85%, or at least 90%, or at least 92.5%, or at least 95%, or at least 97.5%, or at least 98%, or at least 98.5%, or at least 99% or at least 99.5%, or 100% by total weight of polyaryletherketone(s) and flexible thermoplastic polymer(s).

[0198] The composition preferably does not include any reinforcing filler, and in particular no fibers. Indeed, reinforcing fillers generally have the effect of making the material less ductile.

[0199] The composition may comprise, in addition to the polyaryletherketone and the flexible thermoplastic polymer, another polymer miscible with the polyaryletherketone. This other polymer miscible with the polyaryletherketone is therefore integrated into the matrix in which the flexible thermoplastic polymer is dispersed. In other words, it does not form nodules additional to the nodules of flexible thermoplastic polymer(s).

[0200] The composition may also optionally comprise minor amounts, in particular less than 5% by weight relative to the weight of the composition, of functional additives. Examples that may be mentioned as such are antioxidants, stabilizers in the molten and / or solid state, conductive and / or antistatic agents, flame retardants, colorants and reactive agents such as alkali carbonates.

[0201] Thus, according to certain embodiments, the composition may consist of: a polyaryletherketone, a flexible thermoplastic polymer, optionally a polymer other than the polyaryletherketone and the flexible thermoplastic polymer miscible with the polyaryletherketone, and optionally one or more functional additives.

[0202] According to particular embodiments, the composition may consist of polyaryletherketone(s) and flexible thermoplastic polymer(s). It may in particular consist of a single polyaryletherketone and a single flexible thermoplastic polymer. Powder

[0203] The powder according to the invention comprises particles of composition of which several embodiments have been described above.

[0204] Preferably, the powder does not comprise other particles of different chemical composition. The powder is therefore preferably made up of a composition as described above comprising at least one polyaryletherketone and at least one flexible thermoplastic polymer. This has the particular advantage, for example in the embodiments where the powder is used in a method of constructing an object by laser sintering, of being able to implement easy recycling of the powder.

[0205] According to certain embodiments, the particles may have a volume-weighted particle size distribution, as measured by laser diffraction, according to ISO 13320:2009, with a median diameter d50 ranging from 40 to 140 micrometers. Preferably, the median diameter d50 may be from 50 to 120 micrometers. More preferably, the median diameter d50 may be from 60 to 110 micrometers.

[0206] According to certain embodiments, d10 may be greater than or equal to 15 micrometers, or greater than or equal to 30 micrometers.

[0207] According to certain embodiments, d90 may be less than or equal to 300, and preferably less than or equal to 240 micrometers. The value of d90 may, according to certain embodiments, be less than or equal to 180 micrometers.

[0208] According to advantageous embodiments, in particular for an application of the powder in a method of constructing a three-dimensional object layer-by-layer by sintering caused by electromagnetic radiation, the particle size distribution of the powder may be such that:

[0209] dl0>15 pm, 60 pm <d50<l 10 pm, et d90<240 pm.

[0210] According to certain embodiments, in particular for an application of the powder in a method of constructing a three-dimensional object layer by layer by sintering caused by electromagnetic radiation, the particle size distribution powder metric can be such that:

[0211] dl0>30 pm, 80 pm <d50<100 pm, et d90<180 pm.

[0212] According to certain embodiments, the powder does not comprise a flow agent. Advantageously, it can have, even in the absence of a flow agent, a flowability of less than or equal to 10 seconds, preferably less than or equal to 7 seconds, and extremely preferably less than or equal to 5 seconds.

[0213] According to certain embodiments, the powder has a packed density greater than or equal to 500 kg / m3. Such powders used in object manufacturing processes have a density that approaches the desired density for the objects to be manufactured. This makes it possible to have less air from the powder to be evacuated during the object manufacturing process, and therefore to more easily obtain objects having low porosity.

[0214] According to certain embodiments, the powder is an amorphous powder.

[0215] According to certain embodiments, the powder is crystallized, at least in part. powder may in particular have a crystallinity rate greater than or equal to 10%, preferably greater than or equal to 15%, and more preferably greater than or equal to 18%, by weight relative to the total weight of polymers, as measured by X-ray diffraction. Use of powders

[0216] The powders according to the invention can be used in numerous applications, including the applications listed non-exhaustively below.

[0217] The methods for constructing layer-by-layer objects by sintering caused by electromagnetic radiation(s), in particular by infrared radiation and laser radiation, are well known to those skilled in the art. With reference to [Fig.l], the laser sintering device 1 comprises a sintering enclosure 10 in which are arranged a feed tank 40 containing a powder to be sintered, a horizontal plate 30 for supporting the three-dimensional object 80 under construction and a laser 20. The powder is taken from the feed tank 40 and deposited on the horizontal plate 30, forming a thin layer 50 of powder constituting the three-dimensional object 80 under construction. A compactor / scraper roller (not shown) ensures good uniformity of the powder layer 50.The powder layer 50, under construction, is heated using infrared radiation 100 to reach a substantially uniform temperature equal to a predetermined construction temperature Te. In traditional construction processes for sintering PAEK(s)-based powders, Te is generally about 20°C lower than the melting temperature of the powder, as measured by DSC in the first heating with a temperature ramp equal to 20°C / min. In some cases Te may even be lower. The energy required to sinter the powder particles at different points of the powder layer 50 is then provided by laser radiation 200 from the laser 20 moving in the (xy) plane, according to a geometry corresponding to that of the object. The molten powder re-solidifies forming a sintered portion 55 while the remainder of the layer 50 remains in the form of unsintered powder 56. Several passes of laser radiation 200 may be necessary in certain cases. Then, the horizontal plate 30 is lowered along the (z) axis by a distance corresponding to the thickness of a powder layer, and a new layer is deposited. The laser 20 provides the energy required to sinter the powder particles according to a geometry corresponding to this new slice of the object and so on. The procedure is repeated until the object 80 has been manufactured.Once the object 80 is finished, it is removed from the horizontal plate 30 and the unsintered powder 56 can be sieved before being returned, if necessary, to the feed bin 40 to serve as recycled powder.

[0218] The powders according to the invention can also be used in surface coating processes, in particular for metal surfaces. Different processes can be used to obtain a coating on a metal part. One can cite dipping in the fluidized bed for which the metal part is heated then dipped in the fluidized powder bed. It is also possible to carry out so-called electrostatic powdering (charged powder powdered on a metal part connected to the ground), in this case a post-heat treatment is carried out to produce the coating. An alternative is to carry out the powdering on a previously heated part, which makes it possible to eliminate the heat treatment after powdering. Finally, it is possible to carry out flame powdering, in this case the powder is sprayed molten onto a possibly preheated metal part.

[0219] The powders according to the invention can also be used in powder compression processes. These processes are generally used to produce thick parts. In these processes, the powder is first loaded into a mold, then compacted and finally melted to produce the part. Finally, suitable cooling, often quite slow, is carried out in order to limit the presence of internal stresses in the part.

[0220] The objects obtained by these processes have properties which could not be obtained until now due to the impossibility of manufacturing powders comprising at least one flexible thermoplastic polymer dispersed in a matrix of PAEK(s).

[0221] An object obtained by one of the aforementioned processes, preferably obtained by a process for constructing layer-by-layer objects by sintering caused by electromagnetic radiation, may in particular have an elastic modulus strictly less than 4 GPa, as measured on a type 1BA test piece at 23°C according to standard ISO 527-1:2019.

[0222] An object obtained by one of the aforementioned methods, preferably obtained by a method of constructing layer-by-layer objects by sintering caused by electromagnetic radiation, may have a Charpy impact strength greater than or equal to 5 kJ / m2, preferably greater than or equal to 6 kJ / m2, preferably greater than or equal to 7 kJ / m2, preferably greater than or equal to 8 kJ / m2, and extremely preferably greater than or equal to 9 kJ / m2, on a type “A” notched bar according to standard ISO 179:2010. Powder manufacturing process

[0223] A method of manufacturing a powder according to the invention comprises:

[0224] - a step of providing, in the molten state, the composition in the molten state;

[0225] - a step of spraying the composition in the molten state to form droplets of melted composition;

[0226] - a step of cooling the droplets of molten composition to form solid particles; and,

[0227] - optionally one or more heat treatment steps.

[0228] The steps of spraying in the molten state and cooling are known per se for a composition being a pure polymer. They allow the production of a micropowder of said polymer. Such a process has for example been described in patent application EP0945173.

[0229] With reference to [Fig. 2], the molten spraying device 2 comprises means 3 for supplying a molten composition to spray nozzles 4 arranged in the upper part of the device. The spray nozzles 4 spray the molten composition in the form of fine jets which, as they fall, separate into microdroplets 5. The molten droplets are cooled during their fall so as to solidify. In order to reduce the fall height and / or accelerate the cooling, a cryogas, for example liquid nitrogen or liquid carbon dioxide, can be blown in gaseous form inside the device using feeds 6 arranged on the side walls of the device. A solid micropowder 7 is thus obtained in the lower part of the device.

[0230] The molten mixture can be obtained by any method known in the art.

[0231] The composition may for example be provided in the form of PAEK granules in which the flexible thermoplastic polymer has been dispersed. Alternatively, each component may be provided separately and the melt composition may be manufactured in situ by any known melt mixing device suitable for the preparation of thermoplastics. Suitable melt mixing apparatus are, for example, kneaders, Banbury mixers, single screw extruders and twin screw extruders.

[0232] The powder obtained by the spraying process is generally amorphous or quasi-amorphous due to the very rapid cooling of the droplets of molten composition.

[0233] The amorphous powder may, if necessary, undergo one or more heat treatment steps. A (first) heat treatment step may be carried out above the glass transition temperature Tg and below the melting temperature of the polyaryletherketone of the composition so as to cause crystallization of the composition. Optionally, if necessary, a second heat treatment may be carried out so as to uniformize the crystalline phases of the composition. Such a heat-treated powder is particularly suitable for use in a process for constructing layer-by-layer objects by sintering caused by electromagnetic radiation(s).

[0234] For example, according to the embodiments where the polyaryletherketone(s) of the composition is (are) a PEKK essentially consisting of, or consisting of, isophthalic and terephthalic repeat units, with a T / I molar ratio of 45:55 to 75:25, in particular a T / I ratio of approximately 60:40, the heat treatment can be carried out at a temperature of 160°C to 300°C, preferably of 180°C to 290°C, and more preferably of 190°C to 250°C for a time sufficient to obtain the desired crystallinity.

[0235] It is also known that PEKK can crystallize in two crystalline forms, called “form I” and “form II”. When this is the case following the first heat treatment, a second heat treatment can advantageously be carried out so as to obtain a powder essentially containing PEKK crystals of form I. This method is known per se and has already been described in application WO 2012 / 047613. For a powder consisting of a composition comprising a PEKK having a T / I ratio of approximately 60:40, the temperature of the second heat treatment can in particular be from 230°C to 300°C, and preferably from 260°C to 295°C. The temperature of the second heat treatment can in particular be from 275°C to 290°C.

[0236] The temperature of the second heat treatment is generally higher than that of the first heat treatment. Thus, continuing with the example of a powder consisting of a composition comprising a PEKK having a T / I molar ratio of approximately 60:40, a first heat treatment may in particular be carried out at a temperature of 160°C to 250°C and a second heat treatment at a temperature of 260°C to 300°C. Examples Raw materials

[0237] The following commercial products were used for the examples:

[0238] - KEPSTAN® grade 6000, marketed by the company ARKEMA, is a poly- etherketoneketone with a T / I molar ratio of 60 / 40. This PEKK has a viscosity of 900 Pa.s at 380°C and 1 Hz. Five 1 BA specimens were prepared by injection molding on a Battenfeld press using the following parameters: feed 330°C; nozzle: 345°C; mold 80°C. Under these molding conditions, the specimens were obtained in essentially amorphous form. The tensile modulus of elasticity was measured at 2.9 GPa according to standard 527-1:2019, at 23°C, with a crosshead speed of 1 mm / min.

[0239] For comparison, the tensile modulus of elasticity of specimens obtained by laser sintering, having a crystallinity of 20%, was measured at 4 GPa, at 23 °C, with a crosshead speed of 1 mm / min (see Table 2, composition #3c).

[0240] - NEOFLON™ NF101, marketed by the company Daikin, is a copolymer essentially consisting of TFE and HFP repeat units (FEP). This FEP copolymer has a viscosity of 1200 Pa.s at 380°C and 1 Hz. The supplier states that its NEOFLON™ FEP range, including NEOFLONTM NF101, has a tensile modulus of elasticity of 440 to 540 MPa (ASTM D 638).

[0241] - SILTEM® 1500, marketed by the company Sabic, is a block copolymer po- lyetherimide - polydimethylsiloxane (PEI / PDMS). SILTEM® 1500 has a mass proportion of 40% polydimethylsiloxane relative to the total polymer weight and has a viscosity of 800 Pa.s at 380°C and 1 Hz. The supplier states that SILTEM® 1500 has a tensile modulus of elasticity of 590 MPa at a crosshead speed of 1 mm / min (ISO 527).

[0242] The PEKK was mixed with each of the flexible thermoplastic polymers and extruded using a ZSK Mc18 twin-screw extruder, marketed by the company Coperion by introduction into the main hopper and extrusion at a temperature of 320°C. The rotation speed of the screws was 250 rpm for the PEKK and PEI / PDMS block copolymer blend and 320 rpm for the PEKK and FEP blend.

[0243] The granules thus obtained were pulverized in a device as shown in [Fig.2] to obtain a solid powder.

[0244] Two successive heat treatments were carried out. The powder was first treated at 185°C for 6 hours then at 270°C for 3 hours.

[0245] A control powder #3c was also manufactured in order to compare it with the formulated powders of the examples according to the invention. It consists of PEKK and was manufactured by a traditional process of grinding crystallized polymer flakes, followed by a densification step and a heat treatment step.

[0246] PEKK flakes having a viscosity of about 900 Pa.s at 380°C and 1 Hz were synthesized by an electrophilic process. They were first micronized in an Alpine Hosokawa AFG 200 air jet mill at a temperature of 23°C in order to obtain a powder having a particle size distribution d 10=30 microns, d50=69 microns and d90=132 microns.

[0247] This powder, described as “undensified”, was then subjected to thermo-mechanical treatment in a Henschel-type rapid mixer, with a speed at the tip of the blade of the order of 43 m / s, for 60 minutes. A densified powder was thus obtained. The packed density of the densified powder is 440 kg / m3. The densified powder was finally heat treated at 275°C for 4 hours.

[0248] The Table below shows the characteristics of powders #1 to #3c:

[0249] [Tables 1] Polymer Powder blended with PEKK Proportion (% wt) dlO (pm) d50 (pm) d90 (pm) Tapped Density (kg / m3 ) Flowability (s) % crystallinity (% wt) #1 PEI / PD MS 10% 43 95 155 0.59 4 20 #2 FEP 20% 47 90 144 0.54 4 20 #3c * * 30 69 132 0.46 8 20

[0250] Type 1 BA specimens and bars of dimensions 80*10*4 mm3 were printed in the xy plane using a P810 printer, marketed by the company EOS. The construction temperature was set at 285°C and the laser energy at 29 mJ / mm2.

[0251] Type 1 BA specimens were used to determine the tensile modulus of elasticity of an object manufactured by laser powder sintering, at 23°C, with a crosshead speed of 1 mm / min.

[0252] The bars, previously notched in a V shape and then left to rest for 24 hours, were used to determine the Charpy impact resistance.

[0253] The Table below shows the results of these tests:

[0254] [Tables2] Composition Elastic modulus (GPa) Charpy impact (kJ / m2) #1 3 11 #2 3.6 10 #3c 4 4

[0255] Thus, powders #1 and #2, according to the invention, made it possible to manufacture objects obtained by laser sintering based on PEKK and, having a lower elastic modulus and a higher impact resistance, compared to what it was possible to manufacture with powders according to the prior art (powder #3c).

Claims

Claims

1. Powder comprising particles consisting of a composition comprising at least one polyaryletherketone and at least one flexible thermoplastic polymer not being a polyaryletherketone, in which the particles have a volume-weighted particle size distribution, as measured by laser diffraction, according to ISO 13320:2009, with a median diameter d50 strictly less than 500 pm, and preferably less than or equal to 300 pm, the elastic modulus of said at least one flexible thermoplastic polymer being at least two times lower than that of said at least one polyaryletherketone, as measured according to ISO 527-2:2012, at 23°C, on a 1BA type test piece obtained by injection molding, with a crosshead speed of 1 mm / min, said polyaryletherketone forming a matrix in which said flexible thermoplastic polymer is dispersed.

2. The powder of claim 1, wherein said flexible thermoplastic polymer has an elastic modulus of less than or equal to 1.5 GPa, as measured according to ISO 527-2:2012 at 23°C on a type 1BA test piece.

3. Powder according to any one of claims 1 and 2, wherein said at least one flexible thermoplastic polymer is chosen from the list consisting of: a linear polyene, a polysiloxane, a polysiloxane block copolymer, a fluoroelastomer comprising at least one repeating unit derived from: tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride and chlorotrifluoroethylene, and the mixture of these polymers.

4. Powder according to claim 3, wherein said at least one flexible thermoplastic polymer comprises a fluoroelastomer consisting essentially of, or consisting of: a repeating unit derived from tetrafluoroethylene and a repeating unit derived from the monomer of chemical formula CF2=C(F)(R), in which R represents: a -CF3 group or an -ORf group, where Rf is a C1-5 perfluoroalkyl; and, preferably, said flexible thermoplastic polymer consists essentially of, or consisting of, a repeating unit derived from tetrafluoroethylene and a repeating unit derived from hexafluoropropylene.

5. Powder according to claim 3, wherein said at least one flexible thermoplastic polymer comprises a polysiloxane block copolymer, in which the polysiloxane blocks are mono- or di-substituted preferably by Cl to Cl2 alkyl groups, and / or phenyl groups substituted or not by one or more functional groups; and the blocks of units other than the polysiloxanes are preferably polyetherimide, polyaryletherketone, polyarylethersulfone, poly(phenylene sulfide), polyarylamideimide, polyphenylene, poly-benzimidazole and / or polycarbonate blocks.

6. Powder according to any one of claims 1 to 5, in which said at least one flexible thermoplastic polymer represents from 5% to 40%, and preferably from 7% to 25%, by weight relative to the total weight of said at least one flexible thermoplastic polymer and at least one polyaryletherketone of the composition.

7. Powder according to any one of claims 1 to 6, wherein the total weight of said polyaryletherketone(s) and flexible thermoplastic polymer(s) represents at least 85%, or at least 90%, or at least 92.5%, or at least 95%, or at least 97.5%, or at least 98%, or at least 98.5%, or at least 99% or at least 99.5%, or 100%, relative to the total weight of composition.

8. Powder according to any one of claims 1 to 7, wherein the composition consists of: a polyaryletherketone, a flexible thermoplastic polymer, optionally another polymer than said polyaryletherketone(s) and flexible thermoplastic polymer(s), this other polymer being miscible with said at least one polyaryletherketone, and optionally one or more functional additives.

9. Powder according to any one of claims 1 to 8, the particles of which have a volume-weighted particle size distribution, as measured by laser diffraction, according to ISO 13320:2009, with a median diameter d50 ranging from 40 to 140 micrometers, preferably from 50 to 120 micrometers, and more preferably from 60 to 110 micrometers.

10. A powder according to any one of claims 1 to 9 having a tapped density greater than or equal to 500 kg / m3, as measured according to ISO 1068:1975.

11. Powder according to any one of claims 1 to 10 not having a flow agent and having a flowability of less than or equal to 10 seconds, preferably less than or equal to 7 seconds, and

12.

13.

14. extremely preferably less than or equal to 5 seconds, as measured according to method “A” of ISO 6186:1998. Powder according to any one of claims 1 to 11, being amorphous. Powder according to any one of claims 1 to 11, being crystallized, preferably having a crystallinity rate greater than or equal to 10%, and preferably greater than or equal to 15%, and more preferably greater than or equal to 18%, by weight relative to the total weight of polymers, as measured by X-ray diffraction. Powder according to any one of claims 1 to 13, wherein said at least one polyaryletherketone is a polyetherketoneketone, preferably essentially consisting of, and more preferably consisting of: a terephthalic unit and, where appropriate, an isophthalic unit, the terephthalic unit (T) having the chemical formula: [Chem. 19] the isophthalic unit (I) having the chemical formula: [Chem. 20]

15. with a T:I molar ratio ranging from 0:100 to 85:

15. A method of manufacturing a powder according to any one of claims 1 to 14, comprising: - a step of providing, in the molten state, the composition comprising said at least one flexible thermoplastic polymer dispersed in the polymer matrix comprising said at least one polyaryletherketone; - a step of spraying said composition in the molten state, to form droplets of molten composition; - a step of cooling the droplets of molten composition to form solid particles; and, - optionally one or more heat treatment stages.

16. Use of a powder according to any one of claims 1 to 14 in a method of constructing layer-by-layer objects by sintering caused by electromagnetic radiation, in a powder coating method, powder compression molding or powder compression-transfer molding.

17. Object obtained by one of the methods according to claim 16, preferably obtained by a method of constructing layer-by-layer objects by sintering caused by electromagnetic radiation, said object having an elastic modulus strictly less than 4 GPa, as measured on a type 1BA test piece at 23°C according to standard ISO 527-1:2019.

18. Object obtained by one of the methods according to claim 16, preferably obtained by a method of constructing layer-by-layer objects by sintering caused by electromagnetic radiation, said object having a Charpy impact strength greater than or equal to 5 kJ / m2, preferably greater than or equal to 6 kJ / m2, preferably greater than or equal to 7 kJ / m2, preferably greater than or equal to 8 kJ / m2, and extremely preferably greater than or equal to 9 kJ / m2, for a type A notched bar according to standard ISO 179:2010.

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