Powdered composition based on paek, sintering process and object obtained thereby

Abstract

The invention relates to a powdery composition comprising a powder based on at least one polyaryletherketone, said composition having at least one first endothermic peak and one second endothermic peak, the peak temperature of the first endothermic peak being strictly greater than 280°C, the peak temperature of the second endothermic peak having a value equal to 200-280°C; said endothermic peaks being measured on a thermogram obtained by differential scanning calorimetry according to standard ISO 11357-3:2018, on the first heating, using a temperature ramp of 20°C / min. The invention also relates to a method for the electromagnetic radiation-mediated layer-by-layer sintering of three-dimensional objects from a powdery composition, to a method for determining the minimum build temperature to be used, and to objects that can be prepared by this build process.

Description

Technical Field

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

[0002] More specifically, the present invention relates to powdered compositions based on polyaryl ether ketone (PAEK).

[0003] This composition is particularly suitable for use in electromagnetic radiation-mediated layer-by-layer sintering construction processes of objects. Background Technology

[0004] Polyaryl ether ketones (POEs) are well-known high-performance technical polymers. They can be used in applications with limitations imposed by temperature and / or mechanical constraints, and even chemical constraints. They are also suitable for applications requiring excellent fire resistance and minimal smoke or toxic gas emissions. Finally, they exhibit good biocompatibility. These polymers are found in a wide range of fields, including aerospace, offshore drilling, motor vehicles, railroads, marine, wind power, sports, construction, electronics, and medical implants. They can be used in all techniques that utilize thermoplastics, such as molding, compression, extrusion, spinning, powder coating, or sintering.

[0005] Typically, in laser sintering construction, the PAEK powder in the construction layer is heated to a temperature Tc, also known as the "construction temperature" or "bath temperature," in the construction environment. Tc is about 10-20°C below the melting point of the powder (usually 15°C).

[0006] Most of the powder introduced into the sintering machine, typically about 85%-90%, is not sintered at the end of the sintering process: this powder experiences the build temperature and remains at or near that temperature for hours, even tens of hours. This leads to powder aging, particularly changes in the structure of the constituent polymers, especially an increase in their molecular weight, and changes in color, particularly yellowing. The higher the Tc temperature, the faster and more pronounced the powder aging. It then becomes difficult or even impossible to recover the powder, either because sintering the powder is impossible, or because the mechanical properties of the three-dimensional components obtained by laser sintering such recovered powder are reduced and insufficient due to the porosity present in the sintered components.

[0007] As known from patent application EP 3423510, PEKK powder comprising 60% terephthalic acid units and 40% isophthalic acid units has undergone a preliminary heat treatment at 285°C for 120 minutes prior to use in the sintering process. This powder is used in a laser sintering process with a build temperature of 285°C and can be at least partially recycled for use in laser sintering processes with a build temperature also of 285°C.

[0008] There is a need for a composition that can be used in a sintering process at a lower build temperature than the process described above (hereinafter referred to as the "conventional" process) in order to significantly limit the aging of unsintered powder and increase its recyclability.

[0009] Purpose

[0010] The object of this invention is to provide a powder composition that is particularly suitable for use in a layer-by-layer sintering process mediated by electromagnetic radiation, where objects are sintered at a build temperature lower than that of a "conventional" sintering process.

[0011] Another object of the present invention is, in at least some embodiments, to provide a composition that can be more easily and repeatedly recycled in subsequent sintering construction processes.

[0012] Another object of the present invention is to provide, in at least some embodiments, a composition that is produced at a lower cost than the powdered composition used in "conventional" construction processes.

[0013] Another object of the present invention is to provide a layer-by-layer sintering structure construction process for objects using the composition of the present invention mediated by electromagnetic radiation.

[0014] Another object of the present invention is to provide a method for determining the minimum build temperature of a composition that can be sintered in a build process.

[0015] Another object of the present invention is, in at least some embodiments, to provide an object prepared by the process that has the same properties as objects obtained by processes of the prior art. In particular, the object is to obtain an object produced by the process that has good mechanical properties and is therefore sparingly porous. Furthermore, the object is to be able to obtain an object by the process that conforms to precise dimensions and, in particular, is free from any deformation.

[0016] Another object of the present invention is, in at least some embodiments, to provide an object prepared by the process having acceptable mechanical properties and / or a smooth surface appearance. Summary of the Invention

[0017] This invention relates to a powder composition comprising a powder based on at least one polyaryl ether ketone. The composition has at least a first endothermic peak and a second endothermic peak, the peak temperature of the first endothermic peak being strictly greater than 280°C, and the peak temperature of the second endothermic peak having a value equal to or greater than 200°C and 280°C. Preferably, the peak temperature of the first endothermic peak may be greater than or equal to 290°C. Also preferably, the peak temperature of the second endothermic peak may be greater than or equal to 220°C and / or less than or equal to 275°C.

[0018] In some embodiments, the enthalpy measured between 225°C and 280°C may account for 15% to 50% of the total enthalpy measured between 225°C and 330°C. Preferably, in the thermogram, the enthalpy measured between 225°C and 280°C may be greater than or equal to 20% of the total enthalpy measured between 225°C and 330°C and / or less than or equal to 40% of the total enthalpy measured between 225°C and 330°C.

[0019] In some embodiments, the enthalpy measured between 225°C and 280°C can be 5 J / g to 20 J / g. Preferably, the enthalpy measured between 225°C and 280°C can be greater than or equal to 7 J / g and / or less than or equal to 14 J / g. More preferably, the enthalpy measured between 225°C and 280°C can be greater than or equal to 8 J / g and / or less than or equal to 12 J / g.

[0020] The endothermic peak and enthalpy can be measured on the thermogram obtained by differential scanning calorimetry with a temperature ramp of 20 °C / min during the first heating, according to standard ISO 11357-3:2018.

[0021] In some embodiments, the at least one polyaryl ether ketone may be a polyether ketone ketone (PEKK). The PEKK may consist substantially of, and preferably consists of, the following:

[0022] The repeating units of terephthalic acid and isophthalic acid are used. The structural formula of the repeating unit of terephthalic acid is as follows:

[0023]

[0024] The structural formula of the repeating unit of isophthalic acid is:

[0025]

[0026] The molar percentage of terephthalic acid units relative to the sum of isophthalic acid units and terephthalic acid units is 45%-75%. Preferably, the molar percentage of terephthalic acid units relative to the sum of isophthalic acid units and terephthalic acid units can be greater than or equal to 48% and / or less than or equal to 72%. More preferably, it can be greater than or equal to 54% and / or less than or equal to 66%. Very preferably, it can be greater than or equal to 58% and / or less than or equal to 64%.

[0027] In some embodiments, the at least one polyarylether ketone may be a polymer substantially composed of the following or a polymer composed of the following:

[0028] The following are repeating units in the structural formula:

[0029] and

[0030] The following are repeating units in the structural formula:

[0031]

[0032] The molar percentage of unit (III) relative to the sum of units (III) and (IV) is 0%-99%. Preferably, the molar percentage of unit (III) relative to the sum of units (III) and (IV) can be greater than or equal to 55% and / or less than or equal to 95%. More preferably, it can be greater than or equal to 60% and / or less than or equal to 85%. Very preferably, it can be greater than or equal to 65% and / or less than or equal to 75%.

[0033] In some embodiments, the at least one polyarylether ketone may be a polymer substantially composed of the following or a polymer composed of the following:

[0034] The following are repeating units in the structural formula:

[0035] and

[0036] The following are repeating units in the structural formula:

[0037]

[0038] The molar percentage of unit (III) relative to the sum of units (III) and (V) is 0%-99%. Preferably, the molar percentage of unit (III) relative to the sum of units (III) and (V) can be greater than or equal to 5% and / or less than or equal to 97%. More preferably, it can be greater than or equal to 40% and / or less than or equal to 96%. Very preferably, it can be greater than or equal to 70% and / or less than or equal to 95%.

[0039] In some embodiments, the viscosity index of the at least one PAEK is 0.65 dl / g to 1.15 dl / g, which is measured according to standard ISO 307:2019 as a solution in a 96% (by weight) aqueous sulfuric acid solution at 25°C. Preferably, the viscosity index may be greater than or equal to 0.85 dl / g and / or less than or equal to 1.13 dl / g. More preferably, the viscosity index may be greater than or equal to 0.92 dl / g and / or less than or equal to 1.12 dl / g.

[0040] In some embodiments, the powder composition may have a particle size distribution such that the median diameter d of the distribution is... 50 For: d 50 <100μm. Preferably, the particle size distribution is such that: 40μm < d 50 <80μm. More preferably, the particle size distribution results in: d 10 >15μm, 40μm <d 50 <80μm, and d 90 <240μm.

[0041] In some embodiments, the weight of the at least one polyaryl ether ketone may account for at least 50%, or at least 60%, or at least 65%, or at least 75%, or at least 85%, or at least 90%, or at least 95%, or at least 99% of the total weight of the composition. In specific embodiments, the powdered composition may consist, in particular, substantially of the at least one polyaryl ether ketone, or may consist of the at least one polyaryl ether ketone.

[0042] In some embodiments, the powder composition according to the invention may comprise a first powder P1 and a second powder P2, or may consist substantially of either the first powder P1 or the second powder P2, or may consist of either the first powder P1 or the second powder P2, wherein powders P1 and P2 are based independently or not independently of each other on the at least one PAEK. In these embodiments, powder P1 may have at least one endothermic peak with a peak temperature strictly greater than 280°C, preferably greater than or equal to 290°C, and may not have any endothermic peak with a peak temperature less than or equal to 280°C. Powder P2 may have at least one endothermic peak with a peak temperature having a value between 200°C and 280°C, and preferably greater than or equal to 220°C and / or less than or equal to 275°C.

[0043] In some embodiments, powder P1 may comprise powder obtained by heat-treating an initial powder at a temperature greater than or equal to 265°C, or substantially composed of powder obtained by heat-treating an initial powder at a temperature greater than or equal to 265°C, wherein the initial powder has at least one endothermic peak with a peak temperature strictly greater than 280°C and an endothermic peak with a peak temperature of 200°C-280°C. The initial powder may, in particular, be powder P2.

[0044] In some embodiments, P1 may comprise a powder obtained by a layer-by-layer construction method through sintering an initial powder or an initial powder composition, or substantially composed of a powder obtained by a layer-by-layer construction method through sintering an initial powder or an initial powder composition; wherein the initial powder or initial powder composition has at least one endothermic peak with a peak temperature strictly greater than 280°C at a construction temperature greater than or equal to 265°C. The initial powder composition may be a composition according to the invention.

[0045] Advantageously, powder P1 and powder P2 may have substantially the same chemical composition and / or substantially the same viscosity index and / or substantially the same particle size distribution.

[0046] In some embodiments, powder P2 may comprise 1 wt% to 39 wt% of the total weight of powders P1 and P2. Preferably, powder P2 may comprise 3 wt% or more and / or 30 wt% or less of the total weight of powders P1 and P2. More preferably, it may comprise 4 wt% or more and / or 20 wt% or less. Very preferably, it may comprise 5 wt% or more and / or 15 wt% or less. Where appropriate, powder P2 may comprise no more than 38 wt%, no more than 35 wt%, or no more than 30 wt% of the total weight of powders P1 and P2.

[0047] In some embodiments, powder P1 and powder P2 may have a concentration of 200-550 kg / m³, either independently or in conjunction with each other. 3 The tapped density. Preferably, powder P1 and powder P2 can have a tap density of 250-510 kg / m³, either independently or not independently. 3 The tap density. More preferably, they can independently have a tap density of 300-480 kg / m³. 3 The tap density.

[0048] The present invention also relates to a kit for preparing the powdered composition according to the present invention. The kit comprises the aforementioned powders P1 and P2.

[0049] The present invention also relates to a method for determining the minimum build temperature Tc for constructing a three-dimensional object layer by layer by sintering a powdered composition with electromagnetic radiation.

[0050] The method includes providing a thermogram of the powdered composition obtained by differential scanning calorimetry (using a temperature ramp of 20 °C / min during the initial heating). A minimum temperature is determined by integrating the thermogram between 225 °C and Tc to obtain a partial enthalpy of 3.0 J / g to 7.0 J / g, preferably about 5 J / g. Alternatively, the minimum temperature is determined by integrating the thermogram between 225 °C and Tc to obtain a partial enthalpy of 8.0% to 20.0% of the total enthalpy, preferably about 14% of the total enthalpy.

[0051] The present invention also relates to a method for constructing a three-dimensional object layer by layer by sintering the powdered composition with electromagnetic radiation at a minimum construction temperature estimated according to the above method.

[0052] Finally, the present invention relates to an object that can be obtained or directly obtained through the above-described construction process. Attached Figure Description

[0053] The invention will be more clearly understood from the following detailed description of non-limiting embodiments and the accompanying drawings:

[0054] Figure 1 An apparatus for a method of constructing a three-dimensional object layer by layer by sintering at a construction temperature Tc is schematically shown, wherein the composition according to the invention can be advantageously used.

[0055] Figure 2 The DSC thermograms of the powders are shown (from top to bottom): i) P1, ii) P1', iii) P2' and iv) P2. The thermograms were obtained by differential scanning calorimetry (DSC) with a temperature ramp of 20 °C / min during the initial heating, according to standard NF EN ISO 11357-3:2018. The x-axis represents temperature in °C, and the y-axis represents heat flow in W / g.

[0056] Figure 3 Showing in relation to Figure 2The following DSC thermograms were obtained under the same conditions: (from top to bottom): i) Mixture P1:P2 (95:5)% (by weight) (dashed line), ii) Mixture P1:P2 (80:20)% (by weight) (solid line), iii) Mixture P1:P2' (95:5)% (by weight) (dashed line), iv) Mixture P1:P2' (80:20)% (by weight) (solid line), and v) P1 powder (solid line). The x-axis represents temperature in °C, and the y-axis represents heat flux in W / g. Detailed Implementation

[0057] definition

[0058] The term "powder" refers to a fractional state of a substance, typically in the form of very small granules, usually about 100 μm or smaller. The term "powdered" refers to a composition that is in powder form overall.

[0059] The thermograms referenced in this application were obtained by differential scanning calorimetry (DSC) on approximately 10 mg of the test composition during the initial heating, according to standard NF EN ISO 11357-3:2018, using a temperature ramp of 20 °C / min. The initial temperature can be approximately 20 °C, and the final temperature can be approximately 390 °C. For example, a Q2000 differential scanning calorimeter sold by TA Instruments can be used to generate the thermograms, as shown in the attached figures.

[0060] According to standard NF EN ISO 11357-3:2018, the term "melting point" refers to the temperature at which at least some of the crystalline components transform into a viscous liquid state. Unless otherwise specified, it is more specifically the peak melting point, and where appropriate, the temperature of the highest temperature peak in the presence of several endothermic peaks. The term "enthalpy of fusion" refers to the amount of heat required to melt the composition.

[0061] Unless otherwise specified, the definitions in standard ISO 11357-1 2016 apply to this invention. In particular, the following terms are defined as follows:

[0062] A "peak" represents a portion of the DSC curve that separates from the sample baseline to reach a maximum or minimum value and then returns to the sample baseline. Peaks in DSC curves are particularly indicative of first-order transitions.

[0063] • An "endothermic peak" refers to the peak where the heat flux supplied to the sample crucible is higher than that to the reference crucible. This corresponds to the transition of absorbing heat.

[0064] The "baseline" represents the portion of the recorded curve where there is no transition, especially in the case of a primary transition of no melting type. Within the transition zone, a virtual baseline can be defined: this is an imaginary line drawn through the transition zone, assuming zero heat generated by the transition. The virtual baseline can be drawn by interpolating the baseline of the sample using a straight line.

[0065] • “Peak area” refers to the area defined by the peak and the interpolated virtual baseline. It is likened to the enthalpy of transformation and can be expressed in J / g. In this invention, enthalpy is obtained by integrating the peak against the baseline from a temperature of 225°C to a given temperature (e.g., 280°C (“partial enthalpy”) or 330°C (“total enthalpy”)). In this invention, the unit J / g should be understood as “joules” per gram of at least one polyaryl ether ketone. This is particularly important when the composition does not consist of at least one polyaryl ether ketone, for example when the composition contains fillers.

[0066] • "Initial interpolation temperature" represents the intersection of the interpolation virtual baseline and the tangent line at the peak inflection point;

[0067] • "Peak temperature" refers to the temperature at which the distance between the DSC curve and the virtual baseline is greatest during the peak course;

[0068] • "Final interpolation temperature" represents the intersection of the interpolation virtual baseline and the tangent at the peak inflection point;

[0069] The term “glass transition temperature”, written as Tg, is intended to represent the temperature at which at least a portion of an amorphous polymer transitions from a rubbery state to a glassy state, and vice versa. It is measured by differential scanning calorimetry (DSC) using a heating rate of 20 °C / min, according to standard NF ISO 11357-2:2013.

[0070] The rules for representing particle size distribution results are given in ISO 9276, Parts 1 to 6. The term "d" is used in this context. 50 "This refers to the powder particle size value that makes the cumulative volume-weighted particle diameter distribution function equal to 50%." 50 The value is measured by laser diffraction according to standard ISO 13320:2009, for example using a Malvern Mastersizer. Diffractometer. Similarly, "d 10 " and "d 90 "These are the corresponding diameters, such that the cumulative volume-weighted particle diameter function is equal to 10% and 90%, respectively."

[0071] The term "tapered density" (dimensionless) or "tapered volume per unit weight" (kg / m³) 3Density refers to the density per unit weight of a powdery material after compaction or vibration. Vibration density is measured according to standard ISO 1068-1975(F) as follows:

[0072] - Introduce a certain volume of powder into a glass graduated cylinder with a precise graduation of 250ml;

[0073] - If necessary, level the free surface of the powder without tapping, and record the volume V0;

[0074] - Weigh the graduated cylinder containing the powder on a balance with an accuracy of 0.1g. The balance has been pre-tapered.

[0075] - Place the measuring cylinder on the plate of the STAV2003 tapping machine;

[0076] - Tap 1250 times and record the volume V1;

[0077] - Tap 1250 times and record the volume V2;

[0078] Repeat the tapping operation until two equivalent volumes Vi are obtained. Record the Vf corresponding to the same volume Vi.

[0079] Tap density is the weight of the introduced powder divided by Vf. Bulk density is the weight of the introduced powder divided by V0. Both tap density and bulk density are expressed in kg / m³. 3 express.

[0080] The term "flowability" is intended to describe the ability of a powder to flow freely in a uniform and constant manner as individual particles. Flowability here is measured according to method "A" of standard ISO 6186:1998, where a funnel has an orifice with a diameter of 25 mm through which the powdered composition can flow. Incidentally, no antistatic agent is added to the composition. Flowability is measured in seconds.

[0081] The term "viscosity index" refers to the viscosity of a solution measured in a 96% (by weight) aqueous solution of sulfuric acid at 25°C, according to standard ISO 307:2019. The viscosity index is expressed in dl / g.

[0082] The term "polymer mixture" is intended to refer to a macroscopically homogeneous polymer composition. The term also covers compositions consisting of mutually immiscible phases dispersed at the micrometer scale.

[0083] The term "polymer" refers to a polymer obtained by copolymerizing at least two chemically different monomers ("called comonomers"). Therefore, a copolymer is formed from at least two repeating units. It can also be formed from three or more repeating units.

[0084] The abbreviation “PAEK” corresponds to the term “polyaryletherketone”, “PAEKs” corresponds to the term “multiple polyaryletherketones”, and “PAEK(s)” corresponds to the term “one or more polyaryletherketones”.

[0085] The singular forms “one” or “the”, respectively, mean by default: “at least one” and “the at least one” (the latter is not always used to make certain transitional phrases more readable), unless otherwise stated.

[0086] All ranges listed in this patent application include limit values, unless otherwise mentioned.

[0087] Polyaryl ether ketone

[0088] Polyaryl ether ketones (PAEKs) comprise repeating units having the following structural formula:

[0089] (-Ar-X-) and (-Ar1-Y-),

[0090] in:

[0091] -Ar and Ar1 each represent divalent aromatic groups;

[0092] -Ar and Ar1 can preferably be selected from 1,3-phenylene, 1,4-phenylene, 1,1'-biphenylene divalent at the 3,3' position, 1,1'-biphenyl divalent at the 3,4' position, 1,4-naphthylene, 1,5-naphthylene and 2,6-naphthylene;

[0093] -X represents an electron-withdrawing group; it can preferably be selected from carbonyl and sulfonyl groups;

[0094] -Y represents a group selected from oxygen, sulfur, or alkylene atoms, such as -(CH)2- and isopropylene.

[0095] In these units X and Y, at least 50%, preferably at least 70%, and more particularly at least 80% of group X is carbonyl, and at least 50%, preferably at least 70%, and more particularly at least 80% of group Y is oxygen atom.

[0096] According to a preferred embodiment, group X is 100% carbonyl, and group Y is 100% oxygen atom.

[0097] Advantageously, PAEK can be selected from:

[0098] - Polyether ketone ketone, also known as PEKK; PEKK contains one or more repeating units with the structural formula -Ph-O-Ph-C(O)-Ph-C(O)-;

[0099] - Polyetheretherketone, also known as PEEK; PEEK includes one or more repeating units with the structural formula -Ph-O-Ph-O-Ph-C(O)-;

[0100] - Polyetherketone, also known as PEK; PEK contains one or more repeating units with the structural formula -Ph-O-Ph-C(O)-;

[0101] - Polyether ether ketone ketone, also known as PEEKK; PEEKK contains one or more repeating units with the structural formula -Ph-O-Ph-O-Ph-C(O)-Ph-C(O)-;

[0102] - Polyetheretherketone, also known as PEEEK; PEEEK contains one or more repeating units with the structural formula -Ph-O-Ph-O-Ph-C(O)-;

[0103] - Polyether diphenyl ether ketone, also known as PEDEK; PEDEK contains one or more repeating units with the structural formula -Ph-O-Ph-Ph-O-Ph-C(O)-;

[0104] -and their mixtures; and

[0105] - A copolymer comprising at least two of the aforementioned repeating units,

[0106] Wherein: Ph represents phenylene, -C(O)- represents carbonyl, and each phenylene may independently be of the ortho (1-2), meta (1-3) or para (1-4) type, preferably meta or para type.

[0107] Furthermore, defects, end groups, and / or monomers can be incorporated into the polymers listed above in very small amounts without affecting their properties.

[0108] In a specific embodiment, PAEK is PEKK, which is essentially composed of repeating terephthalic acid units and repeating isophthalic acid units, or is composed of repeating terephthalic acid units and repeating isophthalic acid units, wherein the structural formula of the repeating terephthalic acid units is:

[0109]

[0110] The structural formula of the isophthalic acid repeating unit is:

[0111]

[0112] For a given family of polymers, such as the PEKK family, the term "consistently composed of repeating units" means that the repeating units constitute 95%–99.9% of the polymer in molar proportion. Furthermore, the term "consistent with repeating units" means that the repeating units constitute at least 99.9% of the polymer in molar proportion, ideally 100%.

[0113] The choice of the molar ratio of T units relative to the sum of T units and I units is one of the factors that makes it possible to adjust the crystallization rate of polyetherketoneketone.

[0114] A given molar proportion of T units relative to the sum of T units and I units can be obtained by adjusting the respective concentrations of the reagents in a manner known per se during the polymerization process.

[0115] The molar proportion of T units relative to the sum of T and I units in PEKK can be in the following ranges: 0-5%, or 5%-10%, or 10%-15%, or 15%-20%, or 20%-25%, or 25%-30%, or 30%-35%, or 35%-40%, or 40%-45%, or 45%-48%, or 48%-51%, or 51%-54%, or 54%-58%, or 58%-60%, or 60%-62%, or 62%-64%, or 64%-68%, or 68%-72%, or 72%-75%, or 75%-80%, or 80%-85%.

[0116] In embodiments where polyetherketoneketone is a copolymer, it is advantageously a statistical copolymer.

[0117] In certain embodiments, the polyetherketoneketone is essentially composed of, or even entirely of, "T" units and "I" units, with the molar proportion of T units relative to the sum of T and I units being 45%-75%. The molar proportion of T units relative to the sum of T and I units is preferably greater than or equal to 48%, more preferably greater than or equal to 58%. The molar proportion of T units relative to the sum of T and I units is also preferably less than or equal to 72%, more preferably less than or equal to 64%. The molar proportion of T units relative to the sum of T and I units can particularly be about 60%.

[0118] In certain embodiments, PAEK is a polymer consisting essentially of, or even more than, the following:

[0119] The following are repeating units in the structural formula:

[0120] as well as

[0121] The following repeating units:

[0122]

[0123] The molar proportion of unit (III) relative to the sum of units (III) and (IV) can range from 0% to 99%. The molar proportion of unit (III) relative to the sum of units (III) and (IV) is preferably greater than or equal to 55%, more preferably greater than or equal to 60%. It is also preferably less than or equal to 95%, and more preferably less than or equal to 85%.

[0124] In embodiments where the polymer is a copolymer, it is advantageously a statistical copolymer.

[0125] In certain embodiments, PAEK is a polymer consisting essentially of, or even more than, the following:

[0126] The following are repeating units in the structural formula:

[0127] and

[0128] The following are repeating units in the structural formula:

[0129]

[0130] The molar proportion of unit (III) relative to the sum of units (III) and (V) can range from 0% to 99%. The molar proportion of unit (III) relative to the sum of units (III) and (V) is preferably greater than or equal to 5%, more preferably greater than or equal to 40%, and very preferably greater than or equal to 70%. It is also preferably less than or equal to 97%, more preferably less than or equal to 96%, and very preferably less than or equal to 95%.

[0131] In embodiments where the polymer is a copolymer, it is advantageously a statistical copolymer.

[0132] Powder based on at least one polyarylether ketone

[0133] The powder of at least one polyarylether ketone used in the powder composition according to the invention typically comprises at least 50 wt% of PAEK or a mixture of one or more PAEKs relative to the total weight of the powder.

[0134] In some embodiments, the powder comprises, by weight, at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or 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%.

[0135] In some variations, the powder may consist substantially of one or more PAEKs, or may consist of one or more PAEKs. For powder / powder compositions, the term "substantially composed of the component" means that the component constitutes 95%-99.9% of the total weight of the powder / powder composition. Furthermore, the term "composed of the component" means that the component constitutes more than 99.9% of the total weight of the powder / powder composition, ideally 100%.

[0136] In some embodiments, the PAEK-based powder may comprise only one type of PAEK, such as only one PEKK polymer without other types of PAEK. Alternatively, the PAEK-based powder may comprise at least two different types of PAEK, such as a mixture of PEKK and polymers consisting essentially of units (III) and (IV) or even units (III) and (IV), or a mixture of PEKK and polymers consisting essentially of units (III) and (V) or even units (III) and (V).

[0137] In some embodiments, the PAEK-based powder may comprise only one type of PAEK having a given chemical composition, such as a PEKK polymer consisting only of repeating terephthalic acid and isophthalic acid units in a T:I molar ratio of 60:40, without including other types of PAEK. Alternatively, the PAEK-based powder may comprise only one type of PAEK but with a different chemical composition, such as a mixture of PEKK having a T:I molar ratio of 60:40 and PEKK having a T:I molar ratio of 50:50, or a mixture of PELK having a T:I molar ratio of 60:I molar ratio and PEEK having a T:I molar ratio of 55:45.

[0138] In some embodiments, the viscosity index of the powder is 0.65 dl / g to 1.15 dl / g, preferably 0.85 dl / g to 1.13 dl / g, and more preferably 0.92 dl / g to 1.12 dl / g. This viscosity index is determined according to standard ISO 307:2019, as a solution in a 96% (by weight) aqueous sulfuric acid solution at 25°C. These viscosity indices are particularly advantageous and allow for a good trade-off between good coalescence properties during sintering (sufficiently low viscosity) and good mechanical properties in the sintered object (sufficiently high viscosity).

[0139] The powder can be obtained by grinding polymer flakes or grinding extruded particles using techniques known to those skilled in the art.

[0140] The grinding of polymer sheets or the grinding of extruded particles can be carried out at temperatures below -20°C, preferably below -40°C, using liquid nitrogen, liquid carbon dioxide, flake ice, or liquid helium for cooling. In other embodiments, particularly in the case of polymer sheets, grinding can be carried out at room temperature, i.e., particularly at temperatures between 15°C and 35°C, for example, 25°C.

[0141] The particle size distribution of the powder results in a median diameter d. 50 For: d 50 <100μm. Preferably, d 50 It is like this: 40 < d 50 <80. In a more preferred embodiment, the particle size distribution makes d 10 >15μm, 40 <d 50 <80μm and d 90 <240μm. In some implementations, d 90 <220μm or even d 90 <200μm. These particle size distributions are particularly advantageous for powder / powder compositions to be used in the sintering process.

[0142] The powder can have a strength of 200-550 kg / m³ 3 The tap density.

[0143] The tapped density can preferably be greater than or equal to 250 kg / m³ 3 And more preferably greater than or equal to 300 kg / m 3 The tap density can also preferably be less than or equal to 510 kg / m³. 3 And more preferably less than or equal to 480 kg / m 3 .

[0144] powdered composition

[0145] The powdered compositions according to the invention typically comprise at least 50 wt% of PAEK-based powder.

[0146] In some embodiments, (at least one) PAEK-based powder comprises at least 55 wt%, or at least 60 wt%, or at least 65 wt%, or at least 70 wt%, or at least 75 wt%, or at least 80 wt%, or at least 85 wt%, or at least 90 wt%, or at least 95 wt%, or at least 99 wt% of the total weight of the composition.

[0147] In some variations, the composition may consist essentially of PAEK-based powder or may consist of PAEK-based powder.

[0148] In some variations, PAEK-based powder / powder compositions may include one or more other polymers that do not belong to the PAEK family, particularly another thermoplastic polymer, such as polyetherimide (PEI).

[0149] PAEK-based powder / powder compositions may include one or more additives. The additives are typically less than 5 wt% relative to the total weight of the PAEK-based powder / powder composition. Preferably, the additives are less than 1 wt% relative to the total weight of the PAEK-based powder / powder composition. Among the additives may be flow aids, stabilizers (light stabilizers, especially UV stabilizers, and heat stabilizers), fluorescent whitening agents, dyes, pigments, and energy-absorbing additives (including UV absorbers).

[0150] In some embodiments, the PAEK-based powder / powder composition comprises a phosphate ester. This phosphate ester may in particular be a phosphate salt, such as H₂PO₄⁻, HPO₄⁻ 2 -、PO4 3 - A salt or mixture thereof, preferably having sodium, potassium or calcium ions as counterions. Advantageously, phosphate esters are incorporated into PAEK-based powders / compositions in proportions of 500 ppm or more, or 750 ppm or more, or 1000 ppm or more, or 1500 ppm or more, or 2000 ppm or more, or 2500 ppm or more.

[0151] In some embodiments, the powdered composition includes a flow aid, such as hydrophilic or hydrophobic silica. Advantageously, the flow aid comprises 0.01 wt% to 0.4 wt% of the total weight of the composition.

[0152] In other embodiments, the powdered composition does not contain any flow aids.

[0153] PAEK-based powder / powder compositions may also include one or more fillers. The filler content is less than 50 wt%, preferably less than 40 wt%, relative to the total weight of the composition. Among the fillers, reinforcing fillers, particularly mineral fillers such as carbon black, talc, carbon or non-carbon nanotubes, fibers (glass, carbon, etc.), may or may not be ground.

[0154] In addition to PAEK, certain polymers, certain additives, and / or certain reinforcing fillers can be incorporated into the PAEK, for example, by mixing, melt extruding, and then grinding the particles to form a PAEK-based powder incorporating these other components.

[0155] Certain polymers other than PAEK and / or certain additives and / or certain reinforcing fillers may be dry-mixed with PAEK-based powders for incorporation into powdered compositions.

[0156] The powdered composition according to the invention is characterized by DSC thermography, which allows for electromagnetic radiation-mediated sintering at a build temperature lower than that of conventional sintering processes in the prior art.

[0157] The thermogram of the composition includes at least two endothermic peaks. It includes a first endothermic peak with a peak temperature strictly greater than 280°C, preferably greater than or equal to 290°C. It also includes a second endothermic peak with a peak temperature equal to or equal to 200°C-280°C, preferably greater than or equal to 220°C and / or less than or equal to 275°C.

[0158] The enthalpy measured on the thermogram of the composition between 225°C and 280°C can account for 15% to 50% of the total enthalpy measured on the thermogram between 225°C and 330°C.

[0159] Preferably, the enthalpy measured on the thermogram of the composition between 225°C and 280°C may account for 20% or more of the total enthalpy measured on the thermogram between 225°C and 330°C. Preferably, it may also account for 40% or less of the total enthalpy.

[0160] The enthalpy measured between 225℃ and 280℃ can be particularly 5J / g to 20J / g.

[0161] Preferably, the enthalpy measured between 225°C and 280°C can be greater than or equal to 7 J / g, and more preferably greater than or equal to 8 J / g. It can also preferably be less than or equal to 14 J / g, and more preferably less than or equal to 12 J / g.

[0162] In some embodiments, the composition may have a flowability of less than or equal to 15 seconds, more preferably less than or equal to 10 seconds. The composition may particularly have a flowability of less than or equal to 9 seconds, or less than or equal to 7 seconds.

[0163] According to some embodiments, the composition may be a primary composition.

[0164] According to some embodiments, the composition may be a refreshed composition.

[0165] As used herein, the term "replenishment of composition" refers to a composition consisting of a portion of the composition not previously used in the laser sintering process and a portion of the composition that has been used at least once in the laser sintering process. In the context of this invention, powders and compositions not previously used in the laser sintering process are referred to as "primary powders" and "primary compositions," respectively.

[0166] The following embodiments provide specific, non-limiting embodiments of achieving a composition having such a thermogram. It will be apparent to those skilled in the art that certain other variations are also covered by the invention.

[0167] PAEK-based powders can consist of a mixture comprising a first powder P1 and a second powder P2, or substantially composed of the first powder P1 and the second powder P1, or composed of the first powder P2 and the second powder P2. Powders P1 and P2 are based on at least one PAEK.

[0168] Powder P1 has at least one endothermic peak with a peak temperature strictly greater than 280°C, and has no endothermic peak with a peak temperature less than or equal to 280°C. Preferably, powder P1 may have an endothermic peak with a peak temperature greater than or equal to 290°C.

[0169] In some embodiments, powder P1 may include primary powder, or be composed of primary powder.

[0170] In some embodiments, powder P1 may include powder or powder composition that has been used at least once in the laser sintering process, or may consist of powder or powder composition that has been used at least once in the laser sintering process.

[0171] Powder P2 has at least one endothermic peak with a peak temperature of 200°C-280°C. Preferably, powder P2 may have at least one endothermic peak with a peak temperature of 220°C-275°C. In a preferred embodiment, powder P2 may account for 5 wt%-39 wt% of the total weight of powder P1 and powder P2, preferably 10 wt%-39 wt%, more preferably 15 wt%-39 wt%, and very preferably 20 wt%-39 wt%. In some variations, the proportion of powder P2 relative to the total weight of powder P1 and powder P2 may not exceed 38 wt%, or not exceed 35 wt%, or not exceed 30 wt%.

[0172] Powders P1 and P2 can be based on two different PAEKs, or on the same PAEK.

[0173] Advantageously, powders P1 and P2 can be based on the same PAEK. For example, powders P1 and P2 can be based on PEKK, or on a polymer that is essentially composed of repeating units of structural formulas (III) and (IV), or on a polymer that is essentially composed of repeating units of structural formulas (III) and (V). In the following, it is considered that powders P1 and P2 are essentially composed of a single PAEK (e.g., PEKK), or a single PAEK (e.g., PEKK).

[0174] Powders P1 and P2 may have different chemical compositions, i.e., in the case of PEKK, they may have different T:I ratios, and / or powders P1 and P2 may have different viscosity indices, and / or powders P1 and P2 may have different particle size distributions.

[0175] Alternatively, powders P1 and P2 can have the same chemical composition, substantially the same viscosity index, and substantially the same particle size distribution.

[0176] Powders P1 and P2 in the powdered composition can be derived, in particular, from the same initial powder P. In this embodiment, powder P has at least one endothermic peak with a peak temperature strictly greater than 280°C and an endothermic peak with a peak temperature between 200°C and 280°C. In a specific embodiment, powder P can be, for example, PEKK powder (e.g., sold by Arkema). 6002PL powder).

[0177] To obtain powder P1, powder P can be heat-treated. The heat treatment involves heating powder P for a sufficient time at a temperature greater than or equal to 265°C, preferably greater than or equal to 270°C, and most preferably greater than or equal to 275°C. Powder P can particularly be heated to a temperature 1-25°C below its melting point, preferably 10-25°C below its melting point, and most preferably 15-25°C below its melting point. The sufficient duration of this treatment is typically 6 hours or less, preferably 4 hours or less.

[0178] Powder P2 can be derived directly from powder P. Alternatively, powder P can be subjected to other processing to obtain powder P2, but not at temperatures exceeding 260°C, and preferably not at temperatures exceeding 250°C.

[0179] Methods for estimating minimum build temperature

[0180] The minimum build temperature at which powdered compositions, particularly those of the present invention, can be sintered can be estimated by determining the area of ​​the endothermic peak in the composition's thermal spectrum.

[0181] The temperature range for integrating the peak area is approximately between 225℃ and 330℃. The enthalpy measured within this range corresponds to the "total" enthalpy.

[0182] The lowest build temperature corresponds to the temperature at which the enthalpy measured when integrating the thermogram begins at 225 °C is 8.0%–20.0% of the total enthalpy. The measured enthalpy can specifically be 8.0%–9.0%, or 9.0%–10.0%, or 10.0%–11.0%, or 11.0%–12.0%, or 12.0%–13.0%, or 13.0%–14.0%, or 14.0%–15.0%, or 15.0%–16.0%, or 16.0%–17.0%, or 17.0%–18.0%, or 18.0%–19.0%, or 19.0%–20.0% of the total enthalpy. The measured enthalpy can specifically be approximately 14.0% of the total enthalpy.

[0183] Alternatively or additionally, the minimum construction temperature may correspond to the temperature at which the enthalpy measured when the thermogram is started to be integrated at 225°C is equal to 3.0 J / g-7.0 J / g, preferably equal to 5.0 J / g.

[0184] Without wanting to be bound by theory, the inventors believed that heating the composition to an optimal temperature at this point would give the powder bed sufficient cohesion. This would typically eliminate the need for supports to hold the object being constructed within the powder bed. However, this cohesion is not high enough, which would negatively impact the resilience and recyclability of the unsintered composition, as well as the surface (particle appearance) of the constructed object.

[0185] Sintering process

[0186] As described above, the powdered composition is used in device 1 (e.g., Figure 1 In the process of constructing a layer-by-layer sintering structure mediated by electromagnetic radiation of a three-dimensional object in the device shown), the electromagnetic radiation of the object is used.

[0187] Electromagnetic radiation can be, for example, infrared radiation, ultraviolet radiation, or preferably laser radiation. In particular, in situations such as... Figure 1 In the device 1 shown, the electromagnetic radiation may include a combination of infrared radiation 100 and laser radiation 200.

[0188] Sintering is a layer-by-layer fabrication process used to construct three-dimensional objects 80.

[0189] The apparatus 1 includes a sintering chamber 10, in which a feed tank 40 containing a PAEK-based powdered composition and a movable horizontal plate 30 are placed. The horizontal plate 30 can also be used as a support for a three-dimensional object 80 under construction. However, objects prepared from the powdered composition of the present invention generally do not require additional supports and can typically be self-supported by the unsintered powdered composition of the previous layers.

[0190] According to this process, a powdered composition is taken out from the feed tank 40 and deposited onto a horizontal plate 30 to form a thin layer 50 of the powdered composition, which constitutes the three-dimensional object 80 under construction. The powdered composition layer 50 is heated by infrared radiation 100 to achieve a substantially uniform temperature equal to a predetermined minimum build temperature Tc.

[0191] Depending on the geometry corresponding to the object's geometry, the energy required to sinter the powder composition particles at various points in the powder layer 50 is provided by laser radiation 200 from a moving laser 20 in a plane (xy). The molten powder composition is then re-solidified to form the sintered portion 55, while the remainder of layer 50 remains in the form of unsintered powder composition 56. A single pass of laser radiation 200 is generally sufficient to ensure sintering of the powder composition. However, in some embodiments, it is also conceivable to perform multiple and / or several electromagnetic radiations to the same location to ensure sintering of the powder composition.

[0192] Next, the horizontal plate 30 is lowered along the axis (z) by a distance corresponding to the thickness of the powder composition layer, and a new layer is deposited. The laser 20 provides the energy required to sinter the powder composition particles into a geometry corresponding to this new slice of the object, and so on. This process is repeated until a complete object 80 is produced.

[0193] The temperature of the layer beneath the layer being constructed in the sintering chamber 10 can be lower than the construction temperature. However, this temperature is typically maintained above or even significantly above the glass transition temperature of the powdered composition. Particularly advantageously, the temperature at the base of the chamber is maintained at temperature Tb, the so-called "tank bottom temperature," such that Tb is 40°C lower than Tc, preferably 25°C lower, and more preferably 10°C lower.

[0194] Once object 80 is completed, it is removed from the horizontal plate 30, and the unsintered powdered composition 56 can be screened before being at least partially returned to the feed tank 40 for use as recycled powder. Since the build temperature Tc is typically lower than the build temperature of conventional build processes, this allows for the recycling of the powdered composition, which can mitigate the aging of unsintered powdered compositions that have already undergone at least one sintering build temperature condition. The recycled powdered composition can then be used, or as a mixture with fresh powder.

[0195] In particular, in embodiments of the invention where the composition comprises a mixture of powders P1 and P2, the build temperature is lower than that used in conventional build processes (not according to the invention) using a composition comprising powder P1. It is conceivable that improved recycling of the unsintered powdered composition into subsequent builds becomes possible. The unsintered powdered composition may have at least one endothermic peak with a peak temperature strictly greater than 280°C, and no endothermic peak with a peak temperature less than or equal to 280°C. Advantageously, it can be mixed with fresh powder P and / or fresh powder P2 to obtain a replenished powdered composition. The replenished powdered composition still has a build temperature Tc lower than that of conventional build processes.

[0196] Objects that can be obtained through sintering or directly through sintering

[0197] Objects that can be obtained by the sintering process according to the invention or directly by the sintering process according to the invention have mechanical properties at least similar to those of objects obtained by conventional sintering processes and / or better surface appearance.

[0198] In particular, in embodiments of the invention where the composition comprises a mixture of powder P1 and powder P2, the mechanical properties of the object obtained by the method according to the invention are similar to those of the object obtained by using a conventional construction process of the composition comprising powder P1 (which is not according to the invention).

[0199] In particular, in embodiments of the invention where the composition comprises a mixture of powder P1 and powder P2, the surface appearance of the object obtained by the process of the invention is at least similar to, if not better, the surface appearance of the object obtained by using a conventional construction process of the composition comprising powder P1 (which is not according to the invention).

[0200] Example

[0201] Example 1: Preparation of PEKK polymer

[0202] A PEKK polymer is composed of repeating terephthalic acid units and repeating isophthalic acid units, wherein the molar ratio of terephthalic acid units to isophthalic acid units is 60:40.

[0203] The PEKK polymer was prepared as follows:

[0204] o-Dichlorobenzene and 1,4-(phenoxybenzoyl)benzene (EKKE) were placed into a 2L reactor under stirring and nitrogen flow conditions.

[0205] Then, a mixture of acyl chlorides consisting of terephthaloyl chloride, isophthaloyl chloride, and benzoyl chloride is added to the reactor. The reactor is then cooled to -5°C.

[0206] Aluminum trichloride (AlCl3) was added while maintaining the reactor temperature below 5°C. After a homogenization period of approximately 10 minutes, the reactor temperature was increased to 90°C at a rate of 5°C per minute (polymerization is known to begin during this temperature increase). The reactor was held at 90°C for 30 minutes, then cooled to 30°C. A concentrated hydrochloric acid solution (3.3 wt% HCl) was then slowly added, ensuring the reactor temperature did not exceed 90°C. The reactor was stirred for 2 hours, then cooled to 30°C.

[0207] The resulting PEKK is separated from the liquid effluent and then washed in the presence or absence of acid using common separation / washing techniques known to those skilled in the art, to obtain “purified wet PEKK”.

[0208] The purified wet PEKK was dried overnight at 190°C under vacuum (30 mbar). Polymer sheets were obtained. The viscosity index, measured as a solution in a 96% (by weight) aqueous solution of sulfuric acid at 25°C, was 0.93 dl / g, according to standard ISO 307:2019.

[0209] Example 2: Preparation of P2 powder

[0210] The polymer flakes obtained in Example 1 were micronized in an Alpine Hosokawa AFG 200 air jet mill at 23°C to obtain powder P2,d with the following particle size distribution. 10 =21μm, d 50 =50μm, and d 90 =98μm, yield 98%.

[0211] refer to Figure 2 The thermal spectrum of P2 shows three endothermic peaks. More precisely, P2 has two endothermic peaks with peak temperatures between 200℃ and 280℃, and one endothermic peak with a peak temperature greater than or equal to 280℃.

[0212] The measured tap density is 340 kg / m³. 3 .

[0213] Powder P2 does not flow, therefore it cannot be used alone in laser sintering processes.

[0214] Example 3: Preparation of P2' powder

[0215] The powder P2, referred to as "undenitized," was subjected to thermomechanical treatment for 60 minutes at a paddle end speed of approximately 43 m / s in a Henschel rapid mixer. The powder was introduced at room temperature (approximately 23°C). Because the rapid mixer is not temperature-controlled, the temperature during mixing can rise by several degrees Celsius, or even tens of degrees Celsius, but remains below 140°C.

[0216] This yielded a powder P2' known as "densification". The tap density was measured to be 440 kg / m³. 3 .

[0217] Figure 2 The temperature spectrum of P2' is similar to that of P2.

[0218] Example 4: Preparation of P1 powder

[0219] Powder P2' was heat-treated at 285℃ for 4 hours to obtain powder P1.

[0220] refer to Figure 2 The thermal spectrum of P1 showed only one endothermic peak with a shoulder peak (peak temperature: 313℃) (peak temperature: 301℃).

[0221] The known practice in the prior art is to use powders such as powder P1 in laser sintering processes.

[0222] Example 5: Preparation of P1' powder

[0223] Powder P1' was heat-treated at 275℃ for 4 hours to obtain powder P1'.

[0224] refer to Figure 2 The thermal spectrum of P1' shows two endothermic peaks, each with a peak temperature greater than or equal to 280℃.

[0225] Example 6: Powder Mixture

[0226] At room temperature (23°C), Mix in a mixer for 3 minutes to obtain the following powder mixture.

[0227] Flowability was measured according to method “A” of standard ISO 6186:1998, using a funnel with a 25 mm diameter orifice through which the powdered composition could flow without any antistatic agent.

[0228] The table below summarizes the flowability results of compositions containing powders P1 and P2 in different weight ratios:

[0229] P1 (wt%) 100 99 95 90 80 70 60 50 P2 (wt%) 0 1 5 10 20 30 40 50 Liquidity(s) 5 5 6 6 7 9 - -

[0230] Table 1

[0231] The presence of 1 wt% to 30 wt% of powder P2 in a composition consisting of powder P1 and powder P2 allows for the observation of sufficient flowability to enable the composition to be used in a laser sintering process. Compositions containing more than 40 wt% of P2 powder no longer flow (symbol "-") and therefore cannot be used in a laser sintering process.

[0232] The table below summarizes the flowability results of compositions containing powders P1 and P2' in different weight ratios:

[0233] P1 (wt%) 95 80 P'2 (wt%) 5 20 Liquidity(s) 6 6

[0234] Table 2

[0235] The results regarding the flowability obtained using powder P2' are similar to those obtained using powder P2.

[0236] Example 7: Estimation of Bath Temperature

[0237] DSC thermograms were obtained for mixtures #1 to #10. The thermograms for mixtures #1, #3, #9, #5, and #10 are shown below. Figure 3 As shown.

[0238] The table below shows the peak melting point values ​​(T) for total enthalpy and partial enthalpy. 熔融 (expressed in °C), of which total enthalpy (Δ) Hf ΔHp (in J / g) is the integral of the area of ​​the peak relative to a baseline between 225℃ and 330℃, and the partial enthalpy (ΔHp, in J / g) is the integral of the area of ​​the peak relative to a baseline between 225℃ and 280℃.

[0239]

[0240] Table 3

[0241] Estimate minimum bath temperature Tc min This corresponds to the temperature value of 5 J / g measured by integrating the DSC spectrum starting from 225 °C.

[0242] The results are summarized in the table below.

[0243] <![CDATA[Tc min (℃)]]> 279 275 274 273 270 268 NCP NCP 272 268

[0244] Table 4

[0245] The presence of 1 wt% to 30 wt% of powder P2 in a composition consisting of powder P1 and powder P2 can reduce the construction temperature of the construction process compared to a composition consisting of mixture 1 consisting of powder P1 alone.

[0246] The presence of at least 5% powder P2 relative to the build temperature of mixture 1 allows the build temperature to be reduced by at least 5°C.

[0247] The presence of at least 20% powder P2 relative to the build temperature of mixture 1 allows the build temperature to be reduced by at least 9°C.

[0248] Example 8: Instrument Testing

[0249] According to standard ISO 527-2:2012, the 1BA type specimens were prepared by laser sintering using powders according to mixture #1 and powders according to mixture #5. They were prepared at the build temperatures Tc specified in Table 3. min The structure is constructed along the X and Y axes, and the laser sintering energy is 28 mJ / mm². 2 .

[0250] According to standard ISO 527-2:2012, the MTS system sold by MTS Systems Corporation, equipped with a mechanical extensometer, is used. The elastic modulus of the sample was measured at 23°C and a passing speed of 1 mm / min using a machine.

[0251] For specimens prepared using mixture #1 and specimens prepared using mixture #5, a tensile modulus of approximately 4 GPa can be measured, independent of their construction axis.

[0252] Because the sample obtained from mixture #5 was prepared at a build temperature lower than that of the sample obtained from mixture #1, the unsintered powder underwent less aging and could be recycled multiple times into subsequent sintering processes. Furthermore, the process for preparing the sample from mixture #5 was faster than the process for preparing the sample from mixture #1, particularly due to the initial heating step to reach the build temperature and the final cooling step to reach a sufficiently low temperature to handle the powder bed.

[0253] In particular, the fact that the powder in the mixture does not flow makes it impossible to prepare a sample using mixture #7.

Claims

1. A powdered composition comprising a powder based on at least one polyaryl ether ketone, said composition having at least one first endothermic peak and at least one second endothermic peak, The peak temperature of the first endothermic peak is strictly greater than 280°C, and The peak temperature of the second endothermic peak has a value equal to 200°C-280°C; The endothermic peak mentioned therein was measured on a thermogram obtained by differential scanning calorimetry using a temperature ramp of 20°C / min during the first heating, according to standard ISO 11357-3:2018. In the aforementioned thermogram, the enthalpy measured between 225°C and 280°C accounts for 15%-50% of the total enthalpy measured between 225°C and 330°C. in, The composition comprises a first powder P1 and a second powder P2, wherein the powders P1 and P2 are based independently or not independently on the at least one polyarylether ketone; Wherein, the powder P1 has at least one endothermic peak with a peak temperature strictly greater than 280°C, and has no endothermic peak with a peak temperature less than or equal to 280°C; and The powder P2 has at least one endothermic peak with a peak temperature of 200°C-280°C. Wherein, the weight of powder P2 does not exceed 35 wt% of the total weight of powders P1 and P2.

2. The powdered composition according to claim 1, wherein the enthalpy measured between 225°C and 280°C is greater than or equal to 20% of the total enthalpy measured between 225°C and 330°C and / or less than or equal to 40% of the total enthalpy measured between 225°C and 330°C.

3. The powdered composition according to claim 1 or 2, wherein the enthalpy measured between 225°C and 280°C is 5 J / g to 20 J / g.

4. The powder composition according to claim 1, wherein the at least one polyarylether ketone is a polyether ketone ketone.

5. The powdered composition according to claim 4, wherein the polyether ketone ketone comprises the following: Terephthalic acid repeating unit and isophthalic acid repeating unit, wherein the structural formula of the terephthalic acid repeating unit is: （I）； The structural formula of the isophthalic acid repeating unit is: (II); The molar percentage of terephthalic acid units relative to the sum of isophthalic acid and terephthalic acid units is 45%-75%.

6. The powdered composition according to claim 1, wherein the at least one polyarylether ketone is a polymer composed of: The following structural repeating units: (III); and The following structural repeating units: (IV); The molar percentage of unit (III) relative to the sum of units (III) and (IV) is 0%-99%.

7. The powder composition according to claim 1, wherein the at least one polyarylether ketone is a polymer composed of: The following structural repeating units: (III); and The following structural repeating units: （V）； The molar percentage of unit (III) relative to the sum of units (III) and (V) is 0%-99%.

8. The powdered composition according to claim 1, wherein the viscosity index of the at least one polyarylether ketone is 0.65 dl / g-1.15 dl / g, said viscosity index being measured according to standard ISO 307:2019, as a solution at 25°C in a 96% by weight aqueous solution of sulfuric acid.

9. The powdery composition according to claim 1, having a particle size distribution such that the median diameter d 50 of the distribution is: d 50 < 100 pm.

10. The powdered composition according to claim 1, wherein the at least one polyarylether ketone accounts for at least 50% of the total weight of the composition.

11. The powdered composition according to claim 1, wherein it comprises at least one polyarylether ketone.

12. The powdered composition according to claim 1, in, The powder P1 has at least one absorption peak with a peak temperature greater than or equal to 290°C, and no endothermic peak with a peak temperature less than or equal to 280°C; and The powder P2 has at least one endothermic peak with a peak temperature greater than or equal to 220°C and / or less than or equal to 275°C.

13. The powder composition according to claim 1, wherein powder P1 comprises powder obtained by heat-treating an initial powder at a temperature greater than or equal to 265°C, said initial powder having at least one endothermic peak with a temperature strictly greater than 280°C and an endothermic peak with a peak temperature between 200°C and 280°C; or in, Powder P1 includes powder obtained by a layer-by-layer construction method through sintering an initial powder or powder composition, wherein the initial powder or powder composition has at least one endothermic peak at a construction temperature greater than or equal to 265°C, with a temperature strictly greater than 280°C.

14. The powder composition according to claim 1, wherein the powder P1 and the powder P2 have substantially the same chemical composition and / or substantially the same viscosity index and / or substantially the same particle size distribution.

15. The powder composition according to claim 1, wherein the powder P2 accounts for 3% or more and / or 30% or less of the total weight of the powders P1 and P2.

16. A kit for manufacturing a powder composition according to any one of claims 1-15, comprising said powder P1 and powder P2.

17. A method for determining the minimum build temperature Tc for constructing a three-dimensional object layer by layer by sintering a powder composition according to any one of claims 1-15 using electromagnetic radiation, the method comprising: - Provides a thermogram obtained by differential scanning calorimetry for the powdered composition during the initial heating using a temperature ramp of 20°C / min; and - Integrate the thermogram from 225°C to Tc to obtain a partial enthalpy equal to 3.0 J / g-7.0 J / g; or - Integrate the thermograms from 225°C to Tc to obtain the partial enthalpy, which accounts for 8.0%-20.0% of the total enthalpy.

18. A method for constructing a three-dimensional object layer by layer by sintering a powder composition according to any one of claims 1-15 with electromagnetic radiation, said method being carried out at the lowest construction temperature estimated by the method according to claim 17.

19. An object that can be obtained or directly obtained by the method according to claim 18.

Images