Sintered powder (SP) containing thermoplastic polyurethane

Abstract

The present invention relates to a sintering powder (SP) comprising 58.5% to 99.95% by weight of at least one thermoplastic polyurethane (A), 0.05% to 1.5% by weight of at least one flow agent (B), 0% to 5% by weight of at least one organic additive (C), 0% to 5% by weight of at least one further additive (D), and 0% to 30% by weight of at least one toughening agent (E), wherein said percentages by weight are in each case based on the sum of the mass percentages of (A), (B), (C), (D) and (E), and wherein the thermoplastic polyurethane (A) is prepared by reacting at least one isocyanate (a), at least one isocyanate-reactive compound (b) and at least one chain extender (c), and wherein components (a), (b) and (c) each comprise not more than 15 mol % of aromatic moieties, based on the total amount of each component (a), (b) and (c). The invention further relates to a method for producing the sintered powder (SP) and to a method for using the sintered powder (SP) in a three-dimensional (3D) printing process.The invention further relates to a three-dimensional molded article comprising a thermoplastic polyurethane (A), a method for producing a three-dimensional molded article and a method for using at least one thermoplastic polyurethane (A) in a three-dimensional (3D) printing process for producing a three-dimensional molded article to improve the energy return of the three-dimensional molded article.

Description

[Technical field]

[0001] The present invention relates to a sintering powder (SP) comprising 58.5% to 99.95% by weight of at least one thermoplastic polyurethane (A), 0.05% to 1.5% by weight of at least one flow agent (B), 0% to 5% by weight of at least one organic additive (C), 0% to 5% by weight of at least one further additive (D), and 0% to 30% by weight of at least one toughening agent (E), wherein said percentages by weight are in each case based on the sum of the mass percentages of (A), (B), (C), (D) and (E), and wherein the thermoplastic polyurethane (A) is prepared by reacting at least one isocyanate (a), at least one isocyanate-reactive compound (b) and at least one chain extender (c), and wherein components (a), (b) and (c) each comprise not more than 15 mol % of aromatic moieties, based on the total amount of each component (a), (b) and (c). The invention further relates to a method for producing the sintered powder (SP) and to a method for using the sintered powder (SP) in a three-dimensional (3D) printing process.The invention further relates to a three-dimensional molded article comprising a thermoplastic polyurethane (A), a method for producing a three-dimensional molded article and a method for using at least one thermoplastic polyurethane (A) in a three-dimensional (3D) printing process for producing a three-dimensional molded article to improve the energy return of the three-dimensional molded article. [Background technology]

[0002] Providing prototypes quickly is a problem that has become more and more common in recent years. One process that is particularly suited to this so-called "rapid prototyping" is selective laser sintering (SLS). It involves selectively irradiating a polymer powder in a chamber with a laser beam. The powder melts, and the molten particles coalesce and solidify again. Repeated application of polymer powder and subsequent laser irradiation facilitates the creation of three-dimensional parts.

[0003] The selective laser sintering process for producing three-dimensional bodies from ground polymers is described in detail in patent applications US 6,136,948 and WO 96 / 06881.

[0004] A further development of selective laser sintering is high speed sintering (HSS), described in EP 1 648 686 or WO 2019 / 182579, or called HP's Multi Jet Fusion technology (MJF). In high speed sintering, higher process speeds are achieved compared to selective laser sintering by spraying a fusing agent, typically an ink containing at least one radiation absorber, onto the cross-section of the part to be sintered, followed by exposure to an infrared source.

[0005] A further variation in sintering is selective heat sintering (SHS), in which the printing units of a conventional thermal printer are used to selectively melt the polymer powder.

[0006] Recently, the polymers that have been frequently used in selective laser sintering are thermoplastic polyurethanes.

[0007] US 2017 / 0129177 A1 discloses a thermoplastic pulverized composition for producing articles in a powder-based additive manufacturing process, comprising a pulverized thermoplastic polyurethane and 0.02-0.5 wt. % of a plasticizer, based on the total weight of the composition. The thermoplastic polyurethane has at least one organic diisocyanate and groups reactive towards isocyanate groups, and has a number average molecular weight M of 500 g / mol to 6000 g / mol. N and at least one compound having a number average molecular weight M of 60 to 450 g / mol. N and at least one chain extender having the formula:

[0008] US 2020 / 0307076 A1 discloses an additive manufacturing process (3D printing) using particles with a meltable polymer, which has a melting temperature in the range of 160-270 °C (DSC, differential scanning calorimetry; heating twice at a heating rate of 5 K / min) and a Shore D hardness according to DIN ISO 7619-1 of 50 or more, and at a temperature T has a melt volume rate (MVR) according to ISO 1133.2012-02 of 5-15 cm 3 / 10 min, and the change in MVR when the temperature T rises by 20°C is 90 cm 3 / 10 minutes or more thermoplastic polyurethane polymer.

[0009] WO 2015 / 109143 A1 discloses a system and method for solid freeform manufacturing, particularly selective laser sintering, and various articles manufactured therewith, where the system and method uses a thermoplastic polyurethane. The thermoplastic polyurethane is derived from (a) a polyisocyanate component, (b) a polyol component, and (c) an optional chain extender component; the resulting thermoplastic polyurethane has a melting enthalpy of at least 5.5 J / g, a Tc (crystallization temperature) of greater than 70° C., and a Δ(Tm:Tc) of 20 to 75 degrees, where Δ(Tm:Tc) is the difference between Tm (melting temperature) and Tc.

[0010] WO 2020 / 149848 A1 discloses a material kit for three-dimensional (3D) printing comprising a powder bed material comprising thermoplastic polyurethane particles having an average particle size of about 20 μm to about 120 μm and a melting temperature of about 100 ° C to about 250 ° C, wherein the thermoplastic polyurethane particles comprise polyurethane polymer strands having an average of about 10% by weight to about 30% by weight of hard segments based on the total weight of the thermoplastic polyurethane particles, the hard segments comprise a symmetric aliphatic diisocyanate and a symmetric aliphatic chain extender that are polymerized into the thermoplastic polyurethane particles, and a fusing agent comprising a radiation absorber selectively applied to the powder bed material.

[0011] EP 3 540 012 A1 discloses a system and method for solid freeform manufacturing, in particular fused deposition modeling, and various articles manufactured therewith, where the system and method employ a thermoplastic polyurethane derived from (a) a polyisocyanate component, (b) a polyol component, and (c) an optional chain extender component, the resulting thermoplastic polyurethane having a crystallization temperature above 80° C. and a retention of shear storage modulus at 100° C. of 20% or more relative to the shear storage modulus at 20° C.

[0012] However, a drawback of three-dimensional molded articles obtained from sintered powders of the art, including thermoplastic polyurethanes, is that they have a high energy return but a low modulus, or a high modulus but a low energy return. However, for some applications, such as the footwear market, it is important that three-dimensional molded articles obtained from sintered powders exhibit both a high energy return and a high modulus. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] US 6,136,948 [Patent Document 2] WO 96 / 06881 [Patent Document 3] EP 1 648 686 [Patent Document 4] WO 2019 / 182579 [Patent Document 5] US 2017 / 0129177 A1 [Patent Document 6] US 2020 / 0307076 A1 [Patent Document 7] WO 2015 / 109143 A1 [Patent Document 8] WO 2020 / 149848 A1 [Patent Document 9] EP 3 540 012 A1 Summary of the Invention [Problem to be solved by the invention]

[0014] It is therefore an object of the present invention to provide a sintering powder for producing three-dimensional bodies by a three-dimensional printing process, which has to a lesser extent, if at all, the aforementioned disadvantages of the sintering powders and methods described in the prior art, which should be producible and feasible, respectively, in a very simple and inexpensive manner. [Means for solving the problem]

[0015] The purpose is to have the following ingredients: (A) 58.5% to 99.95% by weight of at least one thermoplastic polyurethane, based on the sum of the weight percentages of (A), (B), (C), (D), and (E); (B) 0.05% to 1.5% by weight of at least one flow agent, based on the sum of the weight percentages of (A), (B), (C), (D), and (E); (C) 0% to 5% by weight of at least one organic additive, based on the sum of the weight percentages of (A), (B), (C), (D), and (E); (D) 0% to 5% by weight, based on the sum of the weight percentages of (A), (B), (C), (D), and (E), of at least one further additive; and (E) 0% to 30% by weight of at least one toughening agent, based on the sum of the weight percentages of (A), (B), (C), (D), and (E). This is achieved by sintering powder (SP) containing wherein the at least one thermoplastic polyurethane (A) comprises at least the following components: (a) at least one isocyanate; (b) at least one isocyanate-reactive compound, and (c) at least one chain extender is prepared by reacting Components (a), (b) and (c) each contain up to 15 mole percent aromatic moieties, based on the total amount of each of components (a), (b) and (c).

[0016] Surprisingly, it has been found that three-dimensional mouldings obtained by a three-dimensional (3D) printing process using sintered powders (SP) exhibit both a high energy return and a high modulus of elasticity. The energy return of the three-dimensional mouldings, determined on a 3D printed full disk with the ratios prescribed in the standard according to DIN 53512, is preferably ≧55%, more preferably ≧60%, most preferably ≧62%, particularly preferably ≧65%, and the modulus of elasticity, determined according to ISO 527-1:2019-09, type 1A tensile bar, is preferably in the range of 92-300 MPa, more preferably in the range of 95-280 MPa, most preferably in the range of 100-270 MPa.

[0017] Furthermore, the three-dimensional molded article also exhibits a high elongation at break, preferably ≧50%, more preferably ≧150%, most preferably ≧200%, determined according to ISO 527-1:2019-09, type 1A tensile bar. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 shows the DSC diagram. [Diagram 2] FIG. 2 shows the contact angle θ, the interfacial energy γL of the test liquid, the interfacial energy γS of the sintered powder (SP), and the interfacial energy γSL between the test liquid and the sintered powder (SP). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Sintered Powder (SP) According to the invention, the sintered powder (SP) comprises 58.5% to 99.95% by weight of at least one thermoplastic polyurethane as component (A), 0.05% to 1.5% by weight of at least one flow agent as component (B), 0% to 5% by weight of at least one organic additive as component (C), 0% to 5% by weight of at least one further additive as component (D) and 0% to 30% by weight of at least one reinforcing agent as component (E), said percentages by weight being in each case based on the sum of the percentages by weight of (A), (B), (C), (D) and (E), preferably based on the total weight of the sintered powder (SP).

[0020] The sum of the weight percent of components (A), (B), (C), (D) and (E) is typically 100 weight percent.

[0021] In the context of the present invention, the terms "component (A)" and "at least one thermoplastic polyurethane" are used synonymously and therefore have the same meaning.

[0022] The same applies to the terms "component (B)" and "at least one flow agent". In the context of the present invention, these terms are likewise used synonymously and therefore have the same meaning.

[0023] Likewise, the terms "Component (C)" and "at least one organic additive" are used interchangeably and have the same meaning.

[0024] In the context of the present invention, the terms "component (D)" and "at least one further additive", as well as "component (E)" and "at least one toughening agent", are also used synonymously and therefore have the same meaning.

[0025] Preferably, the sintered powder (SP) comprises 73.3% by weight to 99.9% by weight of component (A), 0.1% by weight to 1.2% by weight of component (B), 0% by weight to 3% by weight of component (C), 0% by weight to 2.5% by weight of component (D) and 0% by weight to 20% by weight of component (E), in each case based on the sum of the mass percentages of components (A), (B), (C), (D) and (E), preferably the total mass of the sintered powder (SP).

[0026] Most preferably, the sintered powder (SP) comprises 74.9% to 99.8% by weight of component (A), 0.2% to 1.1% by weight of component (B), 0% to 1.5% by weight of component (C), 0% to 2.5% by weight of component (D) and 0% to 20% by weight of component (E), in each case based on the sum of the mass percentages of components (A), (B), (C), (D) and (E), preferably the total mass of the sintered powder (SP).

[0027] Particularly preferably, the sintered powder (SP) comprises 75.4% by weight to 99.75% by weight of component (A), 0.25% by weight to 1.0% by weight of component (B), 0% by weight to 1.1% by weight of component (C), 0% by weight to 2.5% by weight of component (D) and 0% by weight to 20% by weight of component (E), in each case based on the sum of the mass percentages of components (A), (B), (C), (D) and (E), preferably the total mass of the sintered powder (SP).

[0028] If the sintered powder (SP) comprises component (C), it comprises, for example, 0.1% by weight to 5% by weight of component (C), preferably 0.1% by weight to 3% by weight of component (C), more preferably 0.3% by weight to 1.5% by weight of component (C), particularly preferably 0.5% by weight to 1.1% by weight of component (C), based on the sum of the mass percentages of components (A), (B), (C), (D) and (E), preferably the total mass of the sintered powder (SP).

[0029] When the sintered powder (SP) comprises component (D), it comprises, for example, in the range of 0.1% to 5% by weight of component (D), preferably in the range of 0.2% to 2.5% by weight of component (D), based on the sum of the mass percentages of components (A), (B), (C), (D) and (E), preferably the total mass of the sintered powder (SP).

[0030] When the sintered powder (SP) comprises component (E), it comprises, for example, in the range of 5% by weight to 30% by weight of component (E), preferably in the range of 10% by weight to 20% by weight of component (E), based on the sum of the mass percentages of components (A), (B), (C), (D) and (E), preferably the total mass of the sintered powder (SP).

[0031] When the sintered powder (SP) comprises component (C), component (D) and / or component (E), the weight percentage of the at least one thermoplastic polyurethane (A) present in the sintered powder (SP) is typically reduced accordingly so that the sum of the weight percentages of the at least one thermoplastic polyurethane (A) and component (B), and of component (C), component (D) and / or component (E) equals 100 weight percent.

[0032] When the sintered powder (SP) comprises components (C) and (D), it comprises, for example, 58.5% by weight to 99.75% by weight of component (A), 0.05% by weight to 1.5% by weight of component (B), 0.1% by weight to 5% by weight of component (C), 0.1% by weight to 5% by weight of component (D), and 0% by weight to 30% by weight of component (E), based on the sum of the mass percentages of components (A), (B), (C), (D) and (E), preferably the total mass of the sintered powder (SP).

[0033] Typically, the sintered powder (SP) comprises particles having a size (D50) in the range of, for example, 10 to 150 μm, preferably in the range of 15 to 130 μm, more preferably in the range of 20 to 110 μm, and particularly preferably in the range of 40 to 100 μm.

[0034] In the context of the present invention, "D50" is understood to mean a particle size such that 50% by volume of the particles are less than or equal to the D50 value, based on the total volume of the particles, and 50% by volume of the particles are greater than the D50 value, based on the total volume of the particles.

[0035] In the context of the present invention, D50 is measured by laser diffraction (Mastersizer 3000, Malvern Panalytical) according to ISO 13320:2020-01 using a dry dispersion at 4 bar. The evaluation is carried out with the aid of the Mie theory.

[0036] The particles also have a size (D10) for example in the range of 10 to 70 μm, preferably in the range of 15 to 60 μm, more preferably in the range of 20 to 40 μm.

[0037] In the context of the present invention, "D10" is understood to mean a particle size such that 10% by volume of the particles are less than or equal to the D10 value, based on the total volume of the particles, and 90% by volume of the particles are greater than the D10 value, based on the total volume of the particles.

[0038] In the context of the present invention, D10 is also measured by laser diffraction (Mastersizer 3000, Malvern Panalytical) according to ISO 13320:2020-01 using a dry dispersion at 4 bar. The evaluation is carried out with the aid of the Mie theory.

[0039] The particles also have a size (D90) for example in the range of 50 to 210 μm, preferably in the range of 80 to 200 μm, more preferably in the range of 80 to 180 μm.

[0040] In the context of the present invention, "D90" is understood to mean a particle size such that 90% by volume of the particles are less than or equal to the D90 value, based on the total volume of the particles, and 10% by volume of the particles are greater than the D90 value, based on the total volume of the particles.

[0041] In the context of the present invention, D90 is also measured according to ISO 13320:2020-01 by laser diffraction (Mastersizer 3000, Malvern Panalytical) using dry dispersions at 4 bar. The evaluation is carried out with the aid of the Mie theory.

[0042] Sintered powders (SP) typically have melting temperatures (T M(SP),H1 ) Preferably, the melting temperature (T M(SP),H1 ) is in the range of 100 to 190°C, more preferably in the range of 120 to 170°C, and particularly preferably in the range of 128 to 168°C.

[0043] Sintered powders (SP) typically have a melting temperature (T M(SP),H2 ) Preferably, the melting temperature (T M(SP),H2 ) is in the range of 125 to 175°C, more preferably in the range of 130 to 175°C, and particularly preferably in the range of 135 to 165°C.

[0044] In the context of the present invention, the melting temperature (T M(SP),H1 ) and melting temperature (T M(SP),H2 ) is determined using a differential scanning calorimeter (DSC; Discovery series DSC, TA Instruments) according to DIN EN ISO 11357-3:2018-04. During the measurement under nitrogen atmosphere, the sample is subjected to the following temperature cycle: equilibration at 0 °C, then heating at 10 °C / min to at least 200 °C (first heating run (H1)), then cooling at 10 °C / min to -80 °C, equilibration at -80 °C, then heating at 10 °C / min to at least 200 °C (second heating run (H2)). This results in a DSC diagram, for example as shown in Figure 1. The "onset of melting (T M オンセット ) and End of Melt (T M エンドセット The terms "melting temperature (T)" and "melting temperature (T)" are known to those skilled in the art. They correspond to the onset and endset of the melting peak, respectively. M(SP),H1) is understood to mean the temperature at which the melting peak of the first heating run (H1) of the DSC diagram has a maximum, and the melting temperature (T M(SP),H2 ) is understood to mean the temperature at which the melting peak of the second heating run (H2) of the DSC diagram has a maximum. The first heating run of the DSC of the TPU according to the invention may show several melting peaks, which are indicated by several maxima in the DSC graph. In this case, (T M(SP),H1 ) is understood as the maximum of the melting peak having the highest melting temperature.

[0045] The sintered powder (SP) generally has a bulk density in the range of 250 to 700 g / L, preferably in the range of 280 to 600 g / L, and more preferably in the range of 310 to 580 g / L.

[0046] In the context of the present invention, bulk density is measured according to DIN EN ISO 60:2000-01. It can be used as a measure of the flowability of the sintered powder (SP). The higher the bulk density, the more flowable the sintered powder (SP).

[0047] The sintered powder (SP) also usually has a melt flow rate (MFR) in the range of 1 to 75 g / 10 min. Preferably, the melt flow rate of the sintered powder (SP) is in the range of 10 to 70 g / 10 min, more preferably in the range of 20 to 65 g / 10 min, and most preferably in the range of 30 to 60 g / 10 min.

[0048] In the context of the present invention, the melt flow rate (MFR) is determined according to DIN EN ISO 1133-1:2012-02, part 1; method B. For this purpose, the sintered powder (SP) is predried in nitrogen at 100°C for 3 hours and then measured at a load of 2.16 kg and a temperature of 190°C.

[0049] The sintered powder (SP) can be produced by any method known to those skilled in the art, for example, the sintered powder is produced by grinding, precipitation, melt emulsification or atomization.

[0050] When the sintered powder (SP) is produced by precipitation, component (A) is usually mixed with a solvent and dissolved therein, optionally with heating, to obtain a solution. The TPU powder is then precipitated, for example by cooling the solution, distilling off the solvent from the solution, or adding a precipitating agent to the solution. Component (B), and optionally components (C), (D) and (E), are typically mixed with the dried TPU powder to obtain the sintered powder (SP).

[0051] Grinding can be carried out in any manner known to those skilled in the art, for example by introducing components (A), (B), and optionally (C), (D) and (E) into a mill where they are ground.

[0052] Suitable grinding mills include all mills known to those skilled in the art, such as classifier mills, counter jet mills, hammer mills, ball mills, vibratory mills, or rotor mills, such as pin mills and vortex mills. The particle size is typically adjusted by a sieving device located downstream of the mill. In a preferred embodiment, a long mesh sieve is used. The use of a long mesh sieve increases the yield of usable material fraction. The mesh size of the sieve is selected so that the above-mentioned D50 value of the sintered powder (SP) can be achieved.

[0053] Grinding in a mill can also be carried out by any method known to those skilled in the art. For example, grinding can be carried out under inert gas and / or while cooling with liquid nitrogen. Cooling with liquid nitrogen is preferred. The temperature during grinding is arbitrary, and grinding is preferably carried out at liquid nitrogen temperature, for example, at a temperature in the range of -210 to -195°C. Thus, the temperature of the components during grinding is, for example, in the range of -60 to 0°C.

[0054] Typically, thermoplastic polyurethanes are granular after production. Therefore, preferably, at least component (A) is in the form of granules before grinding. The granules may be, for example, spherical, cylindrical or ellipsoidal.

[0055] In that case, the following ingredients: (A) 58.5% to 99.95% by weight of at least one thermoplastic polyurethane, based on the sum of the weight percentages of (A), (B), (C), (D), and (E); (B) 0.05% to 1.5% by weight of at least one flow agent, based on the sum of the weight percentages of (A), (B), (C), (D), and (E); (C) 0% to 5% by weight of at least one organic additive, based on the sum of the weight percentages of (A), (B), (C), (D), and (E); (D) 0% to 5% by weight, based on the sum of the weight percentages of (A), (B), (C), (D), and (E), of at least one further additive; and (E) 0% to 30% by weight of at least one toughening agent, based on the sum of the weight percentages of (A), (B), (C), (D), and (E). A sintered powder (SP) comprising: The at least one thermoplastic polyurethane (A) comprises at least the following components: (a) at least one isocyanate; (b) at least one isocyanate-reactive compound, and (c) at least one chain extender is prepared by reacting In one embodiment, a method for producing a sintered powder (SP) in which components (a), (b) and (c) each contain 15 mol % or less of an aromatic moiety, based on the total amount of each component (a), (b) and (c), comprises: a) grinding the total amount of component (A) based on the total mass of the sintered powder (SP) Including, wherein a first portion (BT1) of the total amount of component (B), based on the total mass of the sintered powder (SP), and / or optionally a first portion (CT1) of the total amount of component (C), based on the total mass of the sintered powder (SP), is mixed with component (A) before step a) to obtain powder (P), and a remaining portion (BT2) of the total amount of component (B) and / or optionally a remaining portion (CT2) of the total amount of component (C) is mixed with powder (P) after step a) to obtain sintered powder (SP), said first portion ( the first portion (CT1) accounts for 0 to 100 mass% of the total amount of component (B) based on the total mass of the sintered powder (SP), the first portion (CT1) accounts for 0 to 100 mass% of the total amount of component (C) based on the total mass of the sintered powder (SP), the remaining portion (BT2) accounts for (100-BT1) mass% of the total amount of component (B) based on the total mass of the sintered powder (SP), and the remaining portion (CT2) accounts for (100-CT1) mass% of the total amount of component (C) based on the total mass of the sintered powder (SP); Optionally, a total amount of component (D) based on the total mass of the sintering powder (SP) and / or a total amount of component (E) based on the total mass of the sintering powder (SP) are mixed before step a) or after step a).

[0056] Preferably, at least one organic additive (C) is added to component (A) prior to the grinding operation, which allows a significant increase in the throughput during the grinding operation.

[0057] The mixing method is known to those skilled in the art. Typically, component (B) and / or optionally (C), (D) and / or (E) are mixed with component (A) in dry form. However, it is also possible that mixing is carried out via compounding in an extruder, particularly preferably a twin-screw extruder. However, it is also possible to use a combination of partial compounding and partial dry mixing.

[0058] With regard to the grinding in step a), the details and priorities given above apply analogously to the grinding.

[0059] In a preferred embodiment, the at least one thermoplastic polyurethane (A) is annealed before step a) (in granular form) or after step a) (in powder form). Preferably, the at least one thermoplastic polyurethane (A) is annealed in granular form. This improves the printability of the powder.

[0060] For the purposes of the present invention, the term "annealing" is understood to mean the heat treatment of at least one thermoplastic polyurethane (A).

[0061] Preferably, the at least one thermoplastic polyurethane (A) has a melting temperature (T M(A) ) at a temperature up to 100°C lower than T T , more preferably the melting temperature (T M(A) ) at a temperature up to 70°C lower than T T and particularly preferably at least one thermoplastic polyurethane (A) having a melting temperature (T M(A) ) at a temperature up to 40°C lower than T T It is heated by.

[0062] Further, the at least one thermoplastic polyurethane (A) has a melting temperature (T M(A) ) at least 5°C lower than T T , more preferably the melting temperature (T M(A) ) at least 10°C lower than T T and particularly preferably at least one thermoplastic polyurethane (A) having a melting temperature (T M(A) ) at least 20°C lower than T T It is heated by.

[0063] The at least one thermoplastic polyurethane (A) is preferably heated for at least 3 hours, more preferably at least 10 hours, particularly preferably at least 48 hours. Preferably, the at least one thermoplastic polyurethane (A) is heated for a period not exceeding 7 days. Heat treatment for more than 7 days does not result in improved properties and reduces the commercial value of the sintered powder (SP). Heating is preferably carried out in a paddle dryer (>4 tons) under reduced pressure or protective gas. The protective gas used is, for example, nitrogen.

[0064] The present invention therefore further provides a sintered powder (SP) obtainable by the process of the present invention.

[0065] Component (A) According to the present invention, component (A) is at least one thermoplastic polyurethane.

[0066] In the context of the present invention, "at least one thermoplastic polyurethane" means either exactly one thermoplastic polyurethane (A) or a mixture of two or more thermoplastic polyurethanes (A).

[0067] It is also possible to use mixtures of at least one thermoplastic polyurethane (A) with polymers which are fully or at least partially miscible with the at least one thermoplastic polyurethane (A), as long as the at least one thermoplastic polyurethane (A) is contained in the sintered powder (SP) in an amount of 58.5% to 99.95% by weight, preferably 73.3% to 99.9% by weight, more preferably 74.9% to 99.8% by weight, most preferably 75.4% to 99.75% by weight, based on the sum of the mass percentages of components (A), (B), (C), (D) and (E), preferably the total mass of the sintered powder (SP).

[0068] The at least one thermoplastic polyurethane (A) can be prepared by any method known to a person skilled in the art.

[0069] According to the invention, the at least one thermoplastic polyurethane (A) comprises at least the following components: (a) at least one isocyanate; (b) at least one isocyanate-reactive compound, and (c) at least one chain extender; is prepared by reacting wherein components (a), (b) and (c) each contain no more than 15 mole percent aromatic moieties, based on the total amount of each of components (a), (b) and (c).

[0070] Optionally, the at least one thermoplastic polyurethane (A) is (d) at least one catalyst; (e) at least one additive, and / or (f) at least one reinforcing agent It is also prepared in the presence of

[0071] In the context of the present invention, the term "components (a), (b) and (c) each contain 15 mol % or less aromatic moieties, based on the total amount of each component (a), (b) and (c)" means that component (a) contains 15 mol % or less aromatic moieties, based on the total amount of components (a), (b) contains 15 mol % or less aromatic moieties, based on the total amount of components (b), and component (c) contains 15 mol % or less aromatic moieties, based on the total amount of components (c).

[0072] In a preferred embodiment, components (a), (b) and (c) each contain no more than 10 mol %, preferably no more than 5 mol %, more preferably no more than 1 mol %, of aromatic moieties, based on the total amount of each component (a), (b) and (c). In a particularly preferred embodiment, components (a), (b) and (c) each contain no aromatic moieties.

[0073] In the context of the present invention, aromatic moieties that may be included in component (a) are substituents that contain at least one ring that contains (4n+2) pi electrons (where n=0, 1, 2, etc.) and may also contain heteroatoms. These substituents are typically directly bonded to at least one isocyanate functional group.

[0074] In the context of the present invention, aromatic moieties which may be contained in component (b) are substituents which contain at least one ring containing (4n+2) pi electrons (where n=0, 1, 2, etc.) and which may also contain heteroatoms, and in the main chain (also called backbone by those skilled in the art) of component (b), a segment containing (4n+2) pi electrons (where n=0, 1, 2, etc.) and which may also contain heteroatoms.

[0075] In the context of the present invention, aromatic moieties which may be included in component (c) are substituents which contain at least one ring containing (4n+2) pi electrons (where n=0, 1, 2, etc.) and which may also contain heteroatoms, and a segment containing (4n+2) pi electrons (where n=0, 1, 2, etc.) and which may also contain heteroatoms.

[0076] Component (a) Component (a) is at least one isocyanate.

[0077] In the context of the present invention, "at least one isocyanate" means either exactly one isocyanate or a mixture of two or more isocyanates.

[0078] The at least one isocyanate may be an aliphatic, cycloaliphatic, araliphatic and / or aromatic isocyanate.

[0079] Preferably, component (a) is, for example, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene 1,6-diisocyanate (HDI), heptamethylene diisocyanate, octamethylene diisocyanate, 2-methylpentamethylene 1,5-diisocyanate, 2-ethylbutylene 1,4-diisocyanate, pentamethylene 1,5-diisocyanate (PDI), butylene 1,4-diisocyanate, 1-isocyanato- 3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 1,4-bis(isocyanatomethyl)cyclohexane (1,4-HXDI), 1,3-bis(isocyanatomethyl)cyclohexane (1,3-HXDI), paraphenylene 2,4-diisocyanate (PPDI), tetramethylene xylene 2,4-diisocyanate (TMXDI), dicyclohexylmethane 4,4'-, 2,4'- and 2,2'-diisocyanate (H12 diisocyanates selected from the group consisting of cyclohexane 1,4-diisocyanate, 1-methylcyclohexane 2,4- and 2,6-diisocyanate, diphenylmethane 2,2'-diisocyanate (2,2'-MDI), diphenylmethane 2,4'-diisocyanate (2,4'-MDI), diphenylmethane 4,4'-diisocyanate (4,4'-MDI), naphthylene 1,5-diisocyanate (NDI), tolylene 2,4-diisocyanate (2,4-TDI) and tolylene 2,6-diisocyanate (2,6-TDI), diphenylmethane diisocyanate, 3,3'-dimethyldiphenyl diisocyanate, diphenylethane 1,2-diisocyanate, and phenylene diisocyanate.

[0080] More preferably, component (a) is selected from the group consisting of 1,4-bis(isocyanatomethyl)cyclohexane (1,4-HXDI), tetramethylene xylene 2,4-diisocyanate (TMXDI), hexamethylene 1,6-diisocyanate (HDI), dicyclohexylmethane 2,2'-diisocyanate (H12 MDI), butylene 1,4-diisocyanate, and 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI).

[0081] Most preferably, component (a) is selected from the group consisting of hexamethylene 1,6-diisocyanate (HDI) and dicyclohexylmethane 2,2'-diisocyanate (H12 MDI).

[0082] According to the invention, component (a) contains no more than 15 mol% aromatic moieties, based on the total amount of component (a). Preferably, component (a) contains no more than 10 mol%, more preferably no more than 5 mol%, and most preferably no more than 1 mol% aromatic moieties, based on the total amount of component (a). Particularly preferably, component (a) does not contain aromatic moieties.

[0083] Prepolymers containing free isocyanate groups can also be used as component (a). The NCO content of these prepolymers is preferably between 10% and 25% by mole, based on the initial content of NCO groups employed. These prepolymers can offer the advantage that the pre-reaction during the preparation of the prepolymer shortens the reaction time required for the preparation of the resulting thermoplastic polyurethane (A).

[0084] According to the invention, the prepolymer contains 15 mol% or less of aromatic moieties, based on the total amount of the prepolymer. Preferably, the prepolymer contains 10 mol% or less of aromatic moieties, more preferably 5 mol% or less, and most preferably 1 mol% or less, based on the total amount of the prepolymer. Particularly preferably, the prepolymer does not contain aromatic moieties.

[0085] Ingredient (b) Component (b) is at least one isocyanate-reactive compound.

[0086] In the context of the present invention, "at least one isocyanate-reactive compound" means either exactly one isocyanate-reactive compound or a mixture of two or more isocyanate-reactive compounds.

[0087] At least one isocyanate-reactive compound (b) preferably has, on a statistical average, at least 1.8 and at most 3.0 Zerewitinoff active hydrogen atoms; this number is also called the functionality of the isocyanate-reactive compound (b) and indicates the amount of isocyanate-reactive groups per molecule calculated theoretically from the amount of substance to one molecule. The functionality is more preferably 1.8 to 2.6, most preferably 1.9 to 2.2, and particularly preferably 1.95 to 2.05.

[0088] The at least one isocyanate-reactive compound (b) preferably has a number average molecular weight M, determined according to DIN 55672-1:2016-03, of 500 g / mol to 8000 g / mol, preferably 600 g / mol to 4000 g / mol, more preferably 700 g / mol to 3000 g / mol, particularly preferably 900 g / mol to 2500 g / mol. N has.

[0089] The at least one isocyanate-reactive compound (b) preferably has at least one, more preferably at least two reactive groups selected from hydroxyl, amino, mercapto or carboxylic acid groups. The preferred groups are hydroxyl groups. These compounds are also called polyols or polyhydroxy polyols. The at least one isocyanate-reactive compound (b) is preferably selected from the group consisting of polyester polyols, polyether polyols and polycarbonate diols, more preferably from the group consisting of polyether polyols and polyester polyols.

[0090] Preferred polyols are polyester polyols, preferably polyester diols. Preferred are polyester polyols selected from the following group: polyesters based on adipic acid, succinic acid, pentanedioic acid, sebacic acid or mixtures thereof and 1,2-ethanediol and / or 1,4-butanediol, polyesters based on adipic acid, succinic acid, pentanedioic acid, sebacic acid or mixtures thereof and 1,4-butanediol and / or 1,6-hexanediol, polyesters based on caprolactone and neopentyl glycol and / or 1,4-butanediol (poly-e-caprolactone), adipic acid, succinic acid , polyesters based on pentanedioic acid, sebacic acid or mixtures thereof and polytetramethylene glycol (PTHF) and / or polyesters based on caprolactone and polytetramethylene glycol (polytetrahydrofuran, PTHF), particularly preferably polyesters based on adipic acid and 1,4-butanediol and / or 1,6-hexanediol or polyesters based on adipic acid, succinic acid, pentanedioic acid, sebacic acid or mixtures thereof and polytetramethylene glycol (PTHF) or mixtures thereof.

[0091] Preferred polyols are furthermore polyether polyols, preferably polyether diols, more preferably those based on ethylene oxide, propylene oxide, butylene oxide, such as polypropylene oxide glycol or polybutylene oxide glycol, or polytetrahydrofuran (PTHF), or mixtures thereof. A particularly preferred polyether polyol is polytetrahydrofuran (PTHF).

[0092] In a preferred embodiment, the polyol is polytetrahydrofuran and has a number average molecular weight M, determined according to DIN 55672-1:2016-03, of 500 g / mol to 3,000 g / mol. NMore preferably, the number average molecular weight is from 640 g / mol to 2500 g / mol, even more preferably from 900 g / mol to 1700 g / mol, and most preferably from 950 g / mol to 1500 g / mol. These are commercially available under the trade name PolyTHF®.

[0093] In one embodiment, polyols are used as component (b), in which the content of non-polyether polyols is ≦15% by weight, preferably ≦5% by weight, more preferably ≦1% by weight, based on the total weight of the polyols. In a particularly preferred embodiment, only polyether polyols are used as component (b).

[0094] The present invention therefore further provides a sintered powder (SP), in which a polyol is used as component (b), and the content of polyol which is not a polyether polyol is ≦15% by weight, preferably ≦5% by weight, more preferably ≦1% by weight, based on the total weight of the polyols.

[0095] In another embodiment, a polyol is used as component (b), in which the content of non-polyester polyols is ≦15% by weight, preferably ≦5% by weight, more preferably ≦1% by weight, based on the total weight of the polyols. In a particularly preferred embodiment, only polyester polyols are used as component (b).

[0096] According to the invention, component (b) contains not more than 15 mol% aromatic moieties, based on the total amount of component (b). Preferably, component (b) contains not more than 10 mol%, more preferably not more than 5 mol%, most preferably not more than 1 mol% aromatic moieties, based on the total amount of component (b). Particularly preferably, component (b) does not contain aromatic moieties.

[0097] Ingredient (c) Component (c) preferably has a number average molecular weight M in the range of 50 to 499 g / mol, more preferably in the range of 60 to 130 g / mol. NAt least one chain extender having the formula:

[0098] In the context of the present invention, "at least one chain extender" means either exactly one chain extender or a mixture of two or more chain extenders. Preferably, exactly one chain extender is used as component (c).

[0099] Component (c) may be aliphatic, araliphatic, aromatic and / or cycloaliphatic.

[0100] Preferably, component (c) has two isocyanate-reactive groups.

[0101] Thus, preferred chain extenders are diamines and / or alkanediols, preferably alkanediols.

[0102] In a preferred embodiment, the at least one chain extender (c) is selected from the group consisting of 1,2-ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona- and decaalkylene glycols, dipropylene glycol, 1,4-cyclohexanediol, 1,4-dimethanolcyclohexane, neopentyl glycol, and hydroquinone bis(beta-hydroxyethyl)ether (HQEE).

[0103] Preferably, the at least one chain extender (c) is selected from the group consisting of 1,2-ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona- and decaalkylene glycols.

[0104] Particularly preferably, the at least one chain extender (c) is selected from the group consisting of 1,2-ethylene glycol, 1,3-propanediol, 1,4-butanediol and 1,6-hexanediol.

[0105] According to the invention, component (c) contains not more than 15 mol% aromatic moieties, based on the total amount of component (c). Preferably, component (c) contains not more than 10 mol%, more preferably not more than 5 mol%, most preferably not more than 1 mol% aromatic moieties, based on the total amount of component (c). Particularly preferably, component (c) does not contain aromatic moieties.

[0106] According to the invention, the content of non-alkanediol chain extenders in component (c) is ≦15% by weight, preferably ≦5% by weight, more preferably ≦1% by weight, based on the total weight of the polyols in component (c). In a particularly preferred embodiment, only alkanediols are used as component (c).

[0107] Ingredient (d) Component (d) is at least one catalyst.

[0108] In the context of the present invention, "at least one catalyst (d)" means either exactly one catalyst (d) or a mixture of two or more catalysts (d).

[0109] Such catalysts are known to those skilled in the art. In the context of the present invention, when using a chain extender (component (c)), it is preferred to use a catalyst which promotes the reaction between the NCO groups of at least one isocyanate (component (a)) and the hydroxyl groups of the isocyanate-reactive compound (component (b)).

[0110] Suitable catalysts are, for example, tertiary amines, in particular triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N,N'-dimethylpiperazine, 2-(dimethylaminoethoxy)ethanol and diazabicyclo[2.2.2]octane.

[0111] In the context of the present invention, preference is given to using organometallic compounds, such as titanates, iron compounds, tin compounds and bismuth salts.

[0112] Preferred tin compounds are dialkyltin salts of aliphatic carboxylic acids, such as tin diacetate, tin dioctoate, tin dilaurate. Preferably, tin dioctoate is used.

[0113] Preferred bismuth salts are those in which bismuth is present in the oxidation state 2 or 3, especially 3; preferred are the salts of carboxylic acids, preferably having 6 to 14 carbon atoms, particularly preferably having 8 to 12 carbon atoms.

[0114] Highly preferred bismuth salts are bismuth(III) neodecanoate, bismuth 2-ethylhexanoate, and bismuth octanoate.

[0115] The at least one catalyst (d) is preferably used in an amount of from 0.50 ppm to 1000 ppm, more preferably from 0.75 ppm to 500 ppm, and most preferably from 0.99 ppm to 201 ppm, based on the total weight of components (a), (b), (c) and (d), and optionally (e) and (f).

[0116] It is preferred to use a tin catalyst, especially tin dioctanoate.

[0117] A highly preferred catalyst is SDO (tin(II) 2-ethylhexanoate).

[0118] Ingredient (e) Component (e) is at least one additive.

[0119] In the context of the present invention, "at least one additive (e)" means either exactly one additive (e) or a mixture of two or more additives (e).

[0120] The at least one additive (e) can be the same as the at least one further additive (D) further described below or different from the at least one further additive (D) further described below, preferably different from the at least one further additive (D) further described below.

[0121] However, the at least one additive (e) and the at least one further additive (D) differ in their method of addition: the at least one additive (e) is preferably added to the reaction mixture during the synthesis of component (A) and thus incorporated into the TPU polymer, or added directly to component (A) after its synthesis, whereas the at least one further additive (D) is only added directly before, during or after the production of the sintered powder (SP).

[0122] Preferably, the at least one additive (e) is selected from the group consisting of surface-active substances, flame retardants, nucleating agents, oxidation stabilizers, lubrication and demolding aids, waxes, dyes and pigments, stabilizers against hydrolysis, light, heat or discolouration, and plasticizers.

[0123] Examples of suitable stabilizers include, for example, primary and secondary antioxidants, sterically hindered phenols, hindered amine light stabilizers (HALS), UV absorbers, hydrolysis inhibitors, quenchers and flame retardants. Examples of commercially available stabilizers can be found in Plastics Additives Handbook, 5th Edition, edited by H. Zweifel, Hanser Publishers, Munich, 2001 ([1]), pages 98-136. An example of a commercially available stabilizer is Irganox® from BASF SE.

[0124] Suitable UV absorbers preferably have a number average molecular weight M of at least 200 g / mol, more preferably at least 300 g / mol. N Furthermore, suitable UV absorbers preferably have a number average molecular weight M of at most 10000 g / mol, more preferably at most 5000 g / mol, most preferably at most 3500 g / mol. N has.

[0125] Particularly preferred UV absorbers are UV radiation absorbers selected from the group consisting of cinnamates, oxanilides and benzotriazoles, with benzotriazoles being particularly preferred. Particularly preferred examples of benzotriazoles include Tinuvin® 213, Tinuvin® 234, Tinuvin® 312, Tinuvin® 571, Tinuvin® 384 and Eversorb® 82.

[0126] Typically, the UV absorber is added in an amount of 0.01% to 5% by weight, preferably in an amount of 0.1% to 2.0% by weight, in particular in an amount of 0.2% to 0.7% by weight, based on the weight of components (a), (b), (c) and (e).

[0127] Particularly preferred hindered amine light stabilizers (HALS) are bis(1,2,2,6,6-pentamethylpiperidyl)sebacate (Tinuvin® 765, Ciba Spezialitaetenchemie AG) and the condensation product of 1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidine with succinic acid (Tinuvin® 622). The condensation product of 1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidine with succinic acid (Tinuvin® 622) is particularly preferred. Examples of commercially available HALS stabilizers can be found in Plastics Additives Handbook, 5th edition, H. Zweifel, Hanser Publishers, Munich, 2001, pages 123-136.

[0128] Typically, the HALS is added in an amount of 0.01% to 5% by weight, preferably 0.1% to 2.0% by weight, and especially 0.2% to 0.7% by weight, based on the weights of components (a), (b), (c) and (e).

[0129] A particularly preferred stabilizer comprises a mixture of a phenolic stabilizer, a benzotriazole, and a HALS compound in the preferred amounts described above.

[0130] Component (f) Component (f) is at least one toughening agent.

[0131] In the context of the present invention, "at least one toughening agent (f)" means either exactly one toughening agent (f) or a mixture of two or more toughening agents (f).

[0132] The at least one toughening agent (f) may be the same as the at least one toughening agent (E) further described below, or may be different from the at least one toughening agent (E) further described below.

[0133] For example, the at least one reinforcing agent (f) is selected from the group consisting of carbon nanotubes, carbon fibers, boron fibers, glass fibers, glass beads, silica fibers, ceramic fibers, basalt fibers, aluminum silicate, talc, aramid fibers and polyester fibers. Preferably, talc is used.

[0134] The at least one toughening agent (f) may be added to the reaction mixture during the preparation of component (A), in which case it may be added in dry form or as a masterbatch.

[0135] However, it is also possible not to add the reinforcing agent (f) to the reaction mixture during the preparation of component (A). In this case, it is possible to add at least one reinforcing agent (E), which is further described below, to components (A) and (B), and optionally (C) and (D), during the preparation of the sintered powder (SP).

[0136] It is of course also possible to add at least one reinforcing agent (f) to the reaction mixture during the preparation of component (A) and then add at least one reinforcing agent (E) to components (A) and (B), and optionally (C) and (D), during the preparation of the sintered powder (SP).

[0137] Preparation of component (A) The at least one thermoplastic polymer (A) can be produced in a discontinuous or continuous process, for example the production of the thermoplastic polyurethane (A) is carried out in a single or twin screw reactive extruder, or in a belt line process or a batch casting process.

[0138] Preferably, the preparation of thermoplastic polyurethane (A) is carried out in a continuous process using a twin-screw reactive extruder, in which components (a), (b), (c) and, optionally, components (d), (e) and / or (f) are mixed continuously or simultaneously ("one-shot" process), preferably continuously, and the polymerization reaction is started immediately. Alternatively, a prepolymer process can be used.

[0139] In the prepolymer process, the above isocyanate (component (a)) is reacted in excess with component (b) at a temperature between 30° C. and 200° C., preferably between 80° C. and 180° C. The resulting NCO-terminated polymer is then added to a reactive extruder.

[0140] In the extruder process, components (a), (b) and (c), and optionally components (d), (e) and / or (f), are introduced individually or in the form of a mixture into an extruder and reacted at a temperature preferably between 100° C. and 280° C., more preferably between 140° C. and 250° C. The resulting polyurethane is extruded, cooled and preferably granulated.

[0141] In one embodiment, component (f) is added during the synthesis of the polyisocyanate polyaddition product, preferably the thermoplastic polyurethane (A). In another preferred embodiment, component (f) is added to the polyisocyanate polyaddition product, preferably the thermoplastic polyurethane (A), after its synthesis, preferably in an extruder.

[0142] In order to adjust the hardness and melt flow index of the at least one thermoplastic polyurethane (TPU), the molar ratio of the amounts of components (b) and (c) can be changed, whereby an increase in the content of component (c) increases the hardness and melt viscosity and decreases the melt flow index.

[0143] For the preparation of at least one thermoplastic polyurethane (A), the equivalent ratio of the NCO groups of component (a) to the sum of the hydroxyl groups of components (b) and (c) is preferably 0.95-1.10:1, more preferably 0.98-1.08:1, in particular 0.99-1.05:1.

[0144] For the production of the thermoplastic polyurethane (A) according to the present invention, the molar ratio of component (b) to component (c) is preferably 1:1.0 to 1:8.0, more preferably 1:1.1 to 1:7.0, more preferably 1:1.2 to 1:6.5.

[0145] Ingredient (B) According to the present invention, component (B) is at least one flow agent.

[0146] In the context of the present invention, "at least one flow agent (B)" means either exactly one flow agent (B) or a mixture of two or more flow agents (B).

[0147] Such flow agents are known to those skilled in the art. In the context of the present invention, the at least one flow agent (B) is preferably an inorganic compound.

[0148] The at least one flow agent (B) is, for example, selected from the group consisting of silicon dioxide (silica), silicates, silica, metal oxides and hydroxides, minerals, borates, phosphates, sulfates, and carbonates.

[0149] Examples of suitable silicon dioxide (silica compounds) are hydrated silicon dioxide, vitreous silicon dioxide, and pyrogenic silicon dioxide.

[0150] Examples of suitable silicates include aluminosilicates, alkali metal silicates, alkaline earth metal silicates, alkali metal aluminosilicates, alkaline earth metal aluminosilicates, calcium silicates, and magnesium silicates.

[0151] Examples of suitable silicas include hydrophobic or hydrophilic fumed and / or non-fumed silicas.

[0152] Examples of suitable metal oxides and / or hydroxides include alumina, aluminum hydroxide, titania, magnesium hydroxide, magnesium oxide, calcium oxide, zinc oxide, antimony oxide, and glassy oxides.

[0153] Examples of suitable minerals include talc, mica, kaolin, and attapulgite, with talc, mica, or kaolin being preferred.

[0154] Examples of suitable borates and phosphates are glassy borates and glassy phosphates.

[0155] Examples of suitable sulfates are magnesium sulfate, calcium sulfate, and barium sulfate. Examples of suitable carbonates are magnesium carbonate, calcium carbonate, and barium carbonate.

[0156] Preferably, the at least one flow agent (B) is selected from the group consisting of hydrophobic fumed silica, talc, kaolin, magnesium sulfate, calcium sulfate, barium sulfate, magnesium carbonate, calcium carbonate and barium carbonate.

[0157] Typically, the at least one flow agent (B) comprises particles, for example having a size (D90) of ≦10 μm, preferably ≦2 μm.

[0158] In the context of the present invention, "D90" is understood to mean a particle size such that 90% by volume of the particles are less than or equal to the D90 value, based on the total volume of the particles, and 10% by volume of the particles are greater than the D90 value, based on the total volume of the particles.

[0159] In the context of the present invention, D90 is determined by laser diffraction method (Horiba LA-960, Retsch Technology, Germany) according to ISO 13320:2020-01 before dry dispersion of the sintering powder (SP) or at least one flow agent (B) at 1 bar. The evaluation is carried out by the Fraunhofer method.

[0160] The sintered powder (SP) preferably comprises at least 0.05% by weight, more preferably at least 0.01% by weight, most preferably at least 0.2% by weight and particularly preferably at least 0.25% by weight of component (B), based on the sum of the mass percentages of components (A), (B), optionally (C), optionally (D) and optionally (E), preferably based on the total mass of the sintered powder (SP).

[0161] Furthermore, the sintered powder (SP) preferably comprises at most 1.5% by weight, more preferably at most 1.2% by weight, most preferably at most 1.1% by weight, particularly preferably at most 1.0% by weight of component (B), based on the sum of the mass percentages of components (A), (B), optionally (C), optionally (D) and optionally (E), preferably based on the total mass of the sintered powder (SP).

[0162] Ingredients (C) According to the present invention, component (C) is at least one organic additive.

[0163] In the context of the present invention, "at least one organic additive" means either exactly one organic additive or a mixture of two or more organic additives.

[0164] For example, the at least one organic additive (C) is selected from the group consisting of polyethylene waxes, polypropylene waxes, polypropylene waxes grafted with maleic acid and / or maleic anhydride, amide waxes, fatty acid esters and glycerol fatty acid esters.

[0165] Preferably, component (C) is at least one organic additive selected from polypropylene waxes grafted with maleic acid and / or maleic anhydride, and amide waxes. More preferably, component (C) is an N,N'-alkylene fatty acid diamide. Most preferably, component (C) is N,N'-ethylene di(stearamide).

[0166] Suitable organic additives are available, for example, from Clariant or Baerlocher. One example of a suitable maleic acid and / or maleic anhydride grafted polypropylene wax is Licocene PP MA 6452 TP from Clariant.

[0167] In the context of the present invention, "grafted with maleic acid and / or maleic anhydride" means that the polypropylene wax is branched, with the polypropylene present in the backbone and maleic acid and / or maleic anhydride present in the branches.

[0168] In a preferred embodiment of the present invention, the at least one organic additive (C) has a dropping point D P is selected to satisfy the following condition (Formula I):

number

[0169] In a more preferred embodiment of the present invention, the at least one organic additive (C) has a dropping point D P is selected to satisfy the following condition (Equation II):

[0170]

number

[0171] In a particularly preferred embodiment of the present invention, the at least one organic additive (C) has a dropping point D P is selected to satisfy the following condition (Equation III):

[0172]

number

[0173] Particularly preferably, the at least one organic additive (C) has a dropping point D P is selected to satisfy the following condition (Formula IV):

number

[0174] Dropping point D of at least one organic additive (C) P If it is not possible to determine the melting temperature T M(C) is selected to satisfy the following condition (Equation V):

number

[0175] In a more preferred embodiment of the present invention, the at least one organic additive (C) is at least one organic additive having a melting temperature T M(C) is selected to satisfy the following condition (Formula VI):

[0176]

number

[0177] In a particularly preferred embodiment of the present invention, the at least one organic additive (C) is at least one organic additive having a melting temperature T M(C) is selected to satisfy the following condition (Formula VII):

[0178]

number

[0179] Particularly preferably, the at least one organic additive (C) is at least one organic additive having a melting temperature T M(C) is selected to satisfy the following condition (Formula VIII):

number

[0180] Furthermore, the at least one organic additive (C) preferably reduces the total interfacial energy γ S ≦25mN m -1 , preferably ≦20 mN m -1 , particularly preferably ≦15 mN m -1 The interfacial energy of the dispersed component γD S is preferably ≦20mN m -1 , preferably ≦15 mN m -1 , particularly preferably ≦13 mN m -1 and the interfacial energy of the polar component γ P S is preferably ≦5mN m -1 , preferably ≦4mN m -1 , particularly preferably ≦3 mN m -1 It should be.

[0181] In the context of the present invention, the interfacial energy is calculated using the Owens-Wendt model (Owens, DK; Wendt, RC; Jour. of Applied Polymer Science, 13, 1741, (1969)).

[0182] For this purpose, the ground samples are applied to a homemade adhesive film (Acronal V215 on PET film). Excess material is removed with an air gun. 8-10 drops of the test liquid (ethylene glycol, formamide, water) are applied to the powder layer with a drop volume of about 1.5 μL each. The contact angle θ is determined by a contour analysis of the drop immediately after the first contact with the surface (5 s after the drop separation). The measurements are carried out at 23 °C. The analytical device used is a Drop Shape Analyzer DSA100 (Kruess GmbH, Germany).

[0183] Figure 2 shows the contact angle θ and the interfacial energy γ L , the interfacial energy of sintered powder (SP) γ S , and the interfacial energy γ between the test liquid and the sintered powder (SP) SL The contact angle is measured by applying the test liquid (I) to the sample (II).

[0184] Using the Owens-Wendt equation (Equation IX) and the measured contact angle θ, linear regression can be used to determine the interfacial energy of the polar component, γ P S and the interfacial energy of the dispersed component γ DS The interfacial energy of the powder γ S It is possible to check:

number

[0185] Here, the following relationships should be noted (Formula X and Formula XI):

number

[0186] The sintered powder (SP) preferably comprises at least 0.1% by weight, more preferably at least 0.3% by weight, particularly preferably at least 0.5% by weight of component (C), based on the sum of the mass percentages of components (A), (B), (C), optionally (D) and optionally (E), preferably based on the total mass of the sintered powder (SP).

[0187] Furthermore, the sintered powder (SP) preferably comprises at most 5.0% by weight, more preferably at most 3.0% by weight, most preferably at most 1.5% by weight, particularly preferably at most 1.1% by weight of component (C), based on the sum of the mass percentages of components (A), (B), (C), optionally (D) and optionally (E), preferably based on the total mass of the sintered powder (SP).

[0188] Ingredients (D) Component (D) is at least one further additive.

[0189] In the context of the present invention, "at least one further additive" means either exactly one further additive or a mixture of two or more further additives.

[0190] Such additives are known to those skilled in the art, for example, the at least one further additive is selected from the group consisting of antinucleating agents, stabilizers, conductive additives, end group functionalizing agents, dyes, antioxidants (preferably sterically hindered phenols), flame retardants and color pigments.

[0191] An example of a suitable antinucleating agent is lithium chloride. Suitable stabilizers are, for example, phenols, phosphites, metal soaps and copper stabilizers. Suitable conductive additives are, for example, carbon fibers, metals, stainless steel fibers, carbon nanotubes and carbon black. Suitable end group functionalizing agents are, for example, terephthalic acid, adipic acid and propionic acid. Suitable dyes and color pigments are, for example, carbon black and iron chromium oxide. An example of a suitable antioxidant is Irganox® 245 from BASF SE.

[0192] Flame retardants in the sense of the present invention are inorganic compounds, organic compounds and / or organometallic compounds.Flame retardants can be halogenated compounds, such as brominated or chlorinated compounds, phosphorus-based compounds, such as organic phosphorus compounds or red phosphorus, melamine-based compounds, metal oxide and / or hydroxide compounds, silicon-based compounds, or phosphate and / or phosphinate-based compounds, or mixtures thereof.Preferably, non-halogenated flame retardants are used.

[0193] Examples of metal oxides and hydroxides include antimony trioxide, aluminum trihydroxide (ATH), and magnesium dihydroxide (MDH).

[0194] Examples of melamine-based compounds include pure melamine, melamine derivatives, i.e. salts with organic or inorganic acids, such as boric acid, cyanuric acid, phosphoric acid or pyro / polyphosphoric acid, and melamine homologues, such as melam, melem and melon.

[0195] Examples of phosphate and / or phosphinate based compounds include thiophenyl phosphate, tricresyl phosphate, triphenyl phosphate, cresyl diphenyl phosphate, tri(isopropylphenyl)phosphate, bisaryl phosphates such as resorcinol bisdiphenyl phosphate, bisphenol A bis-diphenyl phosphate (BDP), alkyl phosphonates such as n-alkyl phosphonates, dimeric phosphonates, oligomeric phosphonates and cyclic alkyl phosphonates, ammonium polyphosphates, and metal diethyl phosphinates.

[0196] When the sintered powder (SP) comprises component (D), it preferably comprises at least 0.1% by weight of component (D), more preferably at least 0.2% by weight of component (D), based on the sum of the mass percentages of components (A), (B), optionally (C), (D) and optionally (E), preferably based on the total mass of the sintered powder (SP).

[0197] When the sintered powder (SP) comprises component (D), it also comprises preferably up to 5% by weight of component (D), more preferably up to 2.5% by weight of component (D), based on the sum of the mass percentages of components (A), (B), optionally (C), (D) and optionally (E), preferably based on the total mass of the sintered powder (SP).

[0198] Ingredient (E) According to the present invention, component (E) is at least one toughening agent.

[0199] In the context of the present invention, "at least one toughening agent" means either exactly one toughening agent or a mixture of two or more toughening agents.

[0200] In the context of the present invention, reinforcement agents are understood to mean materials which improve the mechanical properties of the three-dimensional moulding produced by the method of the invention compared to a three-dimensional moulding which does not contain the reinforcement agent.

[0201] Such reinforcing agents are known to those skilled in the art. Component (E) may be, for example, in the form of spheres, platelets or fibers. Preferably, the at least one toughening agent is in the form of a sphere or platelet.

[0202] In the context of the present invention, "platelet-like" is understood to mean that the particles of the at least one reinforcing agent have a diameter to thickness ratio in the range of 4:1 to 10:1, determined by microscopy using image evaluation after ashing.

[0203] Suitable reinforcing agents are known to those skilled in the art and are, for example, selected from the group consisting of carbon nanotubes, glass beads and aluminum silicate.

[0204] The at least one reinforcing agent is preferably selected from the group consisting of glass beads and aluminum silicate, which may further be epoxy-functionalized.

[0205] Suitable aluminum silicates are known to those skilled in the art. Aluminum silicate refers to a compound that contains Al2O3 and SiO2. Structurally, aluminum silicates have in common that silicon atoms are tetrahedrally coordinated by oxygen atoms, and aluminum atoms are octahedrally coordinated by oxygen atoms. Aluminum silicate may further contain additional elements.

[0206] The preferred aluminum silicate is a layered silicate. Particularly preferred aluminum silicate is a calcined aluminum silicate, particularly preferred is a calcined layered silicate. The aluminum silicate may further be epoxy-functionalized.

[0207] When the at least one reinforcing agent is an aluminum silicate, the aluminum silicate can be used in any form. For example, it can be used in the form of pure aluminum silicate, but it is also possible to use the aluminum silicate in mineral form. Preferably, the aluminum silicate is used in mineral form. Suitable aluminum silicates are, for example, feldspar, zeolite, sodalite, sillimanite, andalusite and kaolin. Kaolin is a preferred aluminum silicate. Kaolin is a type of clay rock, and essentially comprises the mineral kaolinite. The empirical formula of kaolinite is Al2[(OH)4 / Si2O5]. Kaolinite is a layered silicate. As well as kaolinite, kaolin typically also comprises further compounds, such as titanium dioxide, sodium oxide and iron oxide. Kaolin preferred according to the present invention comprises at least 98% by weight of kaolinite, based on the total weight of kaolin.

[0208] It will be clear to those skilled in the art that component (E) is different from component (B). Component (E) typically has a higher particle size than component (B), i.e. it has a size (D90) of, for example, >10 μm.

[0209] If the sintered powder comprises component (E), it preferably comprises at least 5% by weight of component (E), more preferably at least 10% by weight of component (E), based on the sum of the mass percentages of components (A), (B) and (E), and optionally (C) and (D), preferably based on the total mass of the sintered powder (SP).

[0210] If the sintered powder (SP) comprises component (E), it also comprises preferably up to 30% by weight of component (E), more preferably up to 20% by weight of component (E), based on the sum of the mass percentages of components (A), (B) and (E), and optionally (C) and (D), preferably based on the total mass of the sintered powder (SP).

[0211] Sintering Method The present invention further comprises the steps of: i) providing a layer of sintering powder (SP); ii) exposing or heating the layer of sintering powder (SP) provided in step i); The present invention provides a method for producing a three-dimensional molded article, comprising:

[0212] Upon exposure to light or heat, at least a portion of the layer of sintering powder (SP) melts. The molten sintering powder (SP) coalesces to form a homogeneous melt. After exposure to light, the molten portion of the layer of sintering powder (SP) is cooled again and the homogeneous melt solidifies again.

[0213] Suitable exposure methods include any method known to those skilled in the art.Preferably, the exposure in step ii) is carried out using a radiation source.The radiation source is preferably selected from the group consisting of an infrared source and a laser.A particularly preferred infrared source is a near infrared source.

[0214] Therefore, the present invention also provides a method, wherein the exposure in step ii) is carried out with a radiation source selected from the group consisting of a laser and an infrared source.

[0215] Suitable lasers are known to those skilled in the art and include, for example, fiber lasers, Nd:YAG lasers (neodymium doped yttrium aluminum garnet lasers), and carbon dioxide lasers, which typically have a wavelength of 10.6 μm.

[0216] If the radiation source used for exposure in step ii) is a laser, the layer of sintering powder (SP) provided in step i) is usually exposed locally and briefly to a laser beam. This selectively melts only those parts of the sintering powder (SP) that are irradiated by the laser beam. If a laser is used in step ii), the method of the invention is also called selective laser sintering. Selective laser sintering is known per se to those skilled in the art.

[0217] When the radiation source used for exposure in step ii) is an infrared source, in particular a near infrared source, the wavelength emitted by the radiation source is typically in the range of 780 nm to 1000 μm, preferably in the range of 780 nm to 50 μm, in particular in the range of 780 nm to 2.5 μm.

[0218] In the exposure in step ii), typically the entire layer of sintering powder (SP) is then exposed. In order that only the desired areas of the sintering powder (SP) are melted during the exposure, typically a fixative (sometimes called ink) containing at least one radiation absorber is applied to the areas to be melted.

[0219] In that case, the method for producing a three-dimensional molded article preferably comprises, between steps i) and ii), step i-1) of applying at least one fusing agent comprising at least one radiation absorber to at least a portion of the layer of sintered powder (SP) provided in step i).

[0220] Therefore, the present invention further comprises the steps of: i) the following ingredients: (A) 58.5% to 99.95% by weight of at least one thermoplastic polyurethane, based on the sum of the weight percentages of (A), (B), (C), (D), and (E); (B) 0.05% to 1.5% by weight of at least one flow agent, based on the sum of the weight percentages of (A), (B), (C), (D), and (E); (C) 0% to 5% by weight of at least one organic additive, based on the sum of the weight percentages of (A), (B), (C), (D), and (E); (D) 0% to 5% by weight, based on the sum of the weight percentages of (A), (B), (C), (D), and (E), of at least one further additive; and (E) 0% to 30% by weight of at least one toughening agent, based on the sum of the weight percentages of (A), (B), (C), (D), and (E). Providing a layer of sintering powder (SP) comprising: The at least one thermoplastic polyurethane (A) comprises at least the following components: (a) at least one isocyanate; (b) at least one isocyanate-reactive compound, and (c) at least one chain extender is prepared by reacting components (a), (b) and (c) each contain 15 mole percent or less of aromatic moieties, based on the total amount of each component (a), (b) and (c); i-1) applying at least one fusing agent comprising at least one radiation absorber to at least a portion of the layer of sintering powder (SP) provided in step i); ii) exposing the layer of sintering powder (SP) provided in step i) to light; Also provided is a method for producing a three-dimensional molded article, comprising:

[0221] Suitable radiation absorbers are all radiation absorbers known to the person skilled in the art, in particular IR absorbers for high speed sintering and multi-jet fusion processes known to the person skilled in the art.

[0222] The fusing agent is typically an ink comprising at least one absorbent that absorbs IR radiation, preferably NIR radiation (near infrared radiation). Upon exposure of the layer of sintering powder (SP) in step ii), absorption of the IR radiation, preferably NIR radiation, by the IR absorbent present in the IR absorbing ink results in selective heating of those parts of the layer of sintering powder (SP) where the IR absorbing ink has been applied.

[0223] The IR absorbing ink may comprise a carrier liquid as well as at least one absorbing agent. Suitable carrier liquids are known to those skilled in the art and are, for example, oil or water.

[0224] The at least one absorbent may be dissolved or dispersed in the carrier liquid.

[0225] When the exposure in step ii) is carried out with a radiation source selected from infrared sources and step i-1) is carried out, the method of the present invention is also called the high speed sintering (HSS) or multi-jet fusion (MJF) method. These methods are known per se to those skilled in the art. In the multi-jet fusion (MJF) method, a "detailing agent", which is typically a non-absorbent ink, is also used.

[0226] After step ii), the layer of sintering powder (SP) is typically lowered by the layer thickness of the layer of sintering powder (SP) provided in step i) and a further layer of sintering powder (SP) is applied, which is then exposed or heated again in step ii).

[0227] This first bonds the upper layer of sintered powder (SP) to the lower layer of sintered powder (SP); furthermore, the particles of sintered powder (SP) in the upper layer are bonded to one another by fusion.

[0228] Thus, in the method of the invention, steps i), ii) and optionally i1) can be repeated.

[0229] By repeating the lowering of the powder bed, the application of the sintered powder (SP), the exposure or heating of the sintered powder (SP), and thus the melting, a three-dimensional (3D) printed article is produced. For example, it is also possible to produce a three-dimensional molded article having a cavity. No additional carrier material is required, since the unmelted sintered powder (SP) itself serves as the carrier material.

[0230] The present invention therefore further provides a three-dimensional moulded article obtainable by a sintering process using the sintered powder (SP) of the present invention.

[0231] The sintering powder (SP) of the present invention is particularly suitable for use in sintering processes.

[0232] Thus, the present invention relates to a three-dimensional (3D) printing process, preferably a sintering process, more preferably a selective laser sintering (SLS) process or a multi-jet fusion (MJF) process, comprising the steps of: (A) 58.5% to 99.95% by weight of at least one thermoplastic polyurethane, based on the sum of the weight percentages of (A), (B), (C), (D), and (E); (B) 0.05% to 1.5% by weight of at least one flow agent, based on the sum of the weight percentages of (A), (B), (C), (D), and (E); (C) 0% to 5% by weight of at least one organic additive, based on the sum of the weight percentages of (A), (B), (C), (D), and (E); (D) 0% to 5% by weight, based on the sum of the weight percentages of (A), (B), (C), (D), and (E), of at least one further additive; and (E) 0% to 30% by weight of at least one toughening agent, based on the sum of the weight percentages of (A), (B), (C), (D), and (E). Also provided is a method of using a sintered powder (SP) comprising: wherein the at least one thermoplastic polyurethane (A) comprises at least the following components: (a) at least one isocyanate; (b) at least one isocyanate-reactive compound, and (c) at least one chain extender is prepared by reacting Components (a), (b) and (c) each contain up to 15 mole percent aromatic moieties, based on the total amount of each of components (a), (b) and (c).

[0233] However, the sintered powder (SP) of the present invention can also be used for the production of three-dimensional molded parts in selective laser sintering (SLS) or multi-jet fusion (MJF) processes, as well as other powder-based 3D printing processes.

[0234] The present invention therefore further provides the use of at least one thermoplastic polyurethane (A) in a three-dimensional (3D) printing process for producing a three-dimensional molded article to improve the energy return of the said three-dimensional molded article, wherein said at least one thermoplastic polyurethane (A) comprises at least the following components: (a) at least one isocyanate; (b) at least one isocyanate-reactive compound, and (c) at least one chain extender is prepared by reacting Components (a), (b) and (c) each contain up to 15 mole percent aromatic moieties, based on the total amount of each of components (a), (b) and (c).

[0235] three-dimensional molded product The method of the present invention provides a three-dimensional molded product. The three-dimensional molded product can be removed from the powder bed after cooling. The adhering particles of unmelted sintered powder can be mechanically removed from the surface by known methods. Surface treatment methods for the three-dimensional molded product include, for example, vibration grinding or barrel polishing, and sand blasting, glass bead blasting or microbead blasting.

[0236] The resulting three-dimensional molded article can also be subjected to further processing, such as surface treatment.

[0237] The present invention therefore further provides a three-dimensional moulded article obtainable by the method of the invention.

[0238] The resulting three-dimensional molded article preferably has a tensile strength of ≧4 MPa, more preferably ≧5 MPa, most preferably ≧6 MPa, and particularly preferably ≧7 MPa. The resulting three-dimensional molded article preferably has an elongation at break of ≧50%, more preferably ≧150%, and most preferably ≧200%. The resulting three-dimensional molded article also preferably has an elastic modulus in the range of 92 to 300 MPa, more preferably in the range of 95 to 280 MPa, and most preferably in the range of 100 to 270 MPa.

[0239] In the context of the present invention, the tensile strength, elongation at break and modulus of elasticity are determined on 3D printed Type 1A tensile bars according to ISO 527-1:2019-09.

[0240] Furthermore, the resulting three-dimensional moulded article preferably has a Shore A hardness, determined according to ISO 7619-1,3s or ISO 48-4, of ≧85, more preferably ≧87, most preferably ≧89.

[0241] Furthermore, the resulting three-dimensional molded article preferably has a density of ≧0.80 g / cm 3 , more preferably ≧0.85 g / cm 3 , most preferably ≧0.90 g / cm 3 , particularly preferably ≧0.95 g / cm 3 of density, determined in accordance with DIN EN ISO 1183-1.

[0242] The energy return of the resulting three-dimensional moulded article is preferably ≧55%, more preferably ≧60%, most preferably ≧62%, particularly preferably ≧65%.

[0243] In the context of the present invention, the energy return is determined on a 3D printed full disc according to DIN 53512 with the ratios prescribed in the standard.

[0244] Three-dimensional parts can be 3D printed by selective laser sintering (SLS) or multi-jet fusion (MJF).

[0245] Regarding selective laser sintering (SLS), any machine for printing three-dimensional parts can be used. One possible approach is to use an EOS P1 with the following two printing parameter settings:

[0246] The first printing parameter settings include heating the process chamber to 107.5°C ± 1°C, heating the removal chamber to 52°C, and setting the warm-up time to 70 minutes. For powder application, a layer thickness of 0.1 mm is used with a minimum layer time of 13 seconds. The infill (hatched) energy density is 40 mJ / mm 2 The speed is 3000mm / s, the power is 12W, and the hatching distance is 0.1mm. The contour has a 33mmJ / mm 2 Double scanning can be used with an energy density of 1000 nm, a speed of 3000 mm / s and a power of 9.9 W.

[0247] The second printing parameter settings include heating the process chamber to 139°C ± 1°C, heating the removal chamber to 116.5°C, and setting the warm-up time to 70 minutes. A layer thickness of 0.1 mm can be used for powder application. The energy density of the infill (hatched) is 36 mJ / mm 2 The contour can be set to 38 mmJ / mm 2 A double scan can be used at an energy density of 100 nm.

[0248] For Multi Jet Fusion (MJF), any machine for printing three-dimensional parts can be used, for example, HP JT Fusion 5200 printer, HP JT Fusion 5210 printer, and HP JT Fusion 5210 Pro can be used. As printing parameter settings, 5300 followed by the application of fuse layer can be used with printing mode of BASF Ultrasint TPU01 material.

[0249] The resulting three-dimensional molded article typically comprises 58.5% to 99.95% by weight of component (A), 0.05% to 1.5% by weight of component (B), 0% to 5% by weight of component (C), 0% to 5% by weight of component (D) and 0% to 30% by weight of component (E), in each case based on the total weight of the three-dimensional molded article.

[0250] Thus, the present invention further comprises a composition comprising the following components: (A) 58.5% to 99.95% by weight of at least one thermoplastic polyurethane, based on the sum of the weight percentages of (A), (B), (C), (D), and (E); (B) 0.05% to 1.5% by weight of at least one flow agent, based on the sum of the weight percentages of (A), (B), (C), (D), and (E); (C) 0% to 5% by weight of at least one organic additive, based on the sum of the weight percentages of (A), (B), (C), (D), and (E); (D) 0% to 5% by weight, based on the sum of the weight percentages of (A), (B), (C), (D), and (E), of at least one further additive; and (E) 0% to 30% by weight of at least one toughening agent, based on the sum of the weight percentages of (A), (B), (C), (D), and (E). To provide a three-dimensional molded article comprising: wherein the at least one thermoplastic polyurethane (A) comprises at least the following components: (a) at least one isocyanate; (b) at least one isocyanate-reactive compound, and (c) at least one chain extender is prepared by reacting Components (a), (b) and (c) each contain up to 15 mole percent aromatic moieties, based on the total amount of each of components (a), (b) and (c).

[0251] The three-dimensional moulded articles are preferably lattices, cushions, seats, mattresses, protective gear, helmets, shoes, shoe soles and shoe insoles.

[0252] Preferably, the three-dimensional molded article comprises 73.3% by weight to 99.9% by weight of component (A), 0.1% by weight to 1.2% by weight of component (B), 0% by weight to 3% by weight of component (C), 0% by weight to 2.5% by weight of component (D) and 0% by weight to 20% by weight of component (E), in each case based on the total weight of the three-dimensional molded article.

[0253] Most preferably, the three-dimensional molded article comprises 74.9% by weight to 99.8% by weight of component (A), 0.2% by weight to 1.1% by weight of component (B), 0% by weight to 1.5% by weight of component (C), 0% by weight to 2.5% by weight of component (D) and 0% by weight to 20% by weight of component (E), in each case based on the total weight of the three-dimensional molded article.

[0254] Particularly preferably, the three-dimensional molded article comprises 75.4% by weight to 99.75% by weight of component (A), 0.25% by weight to 1.0% by weight of component (B), 0% by weight to 1.1% by weight of component (C), 0% by weight to 2.5% by weight of component (D) and 0% by weight to 20% by weight of component (E), in each case based on the total weight of the three-dimensional molded article.

[0255] It will be apparent to one of ordinary skill in the art that the weight percentages of components (A), (B), (C), (D) and (E) typically add up to 100 weight percent.

[0256] When the three-dimensional molded article contains component (C), it contains, for example, 0.1 mass % to 5 mass % of component (C), preferably 0.1 mass % to 3 mass % of component (C), more preferably 0.3 mass % to 1.5 mass % of component (C), and particularly preferably 0.5 mass % to 1.1 mass % of component (C), based on the total mass of the three-dimensional molded article.

[0257] When the three-dimensional molded article contains component (D), it contains, for example, component (D) in the range of 0.1 mass% to 5 mass%, preferably component (D) in the range of 0.2 mass% to 2.5 mass%, based on the total mass of the three-dimensional molded article.

[0258] When the three-dimensional molded article contains component (E), it contains, for example, component (E) in the range of 5% by mass to 30% by mass, preferably 10% by mass to 20% by mass, based on the total mass of the three-dimensional molded article.

[0259] When the three-dimensional molded article comprises component (C), component (D) and / or component (E), the weight percentage of the at least one thermoplastic polyurethane (A) present in the three-dimensional molded article is typically reduced accordingly, so that the sum of the weight percentage of the at least one thermoplastic polyurethane (A), the weight percentage of component (B), the weight percentage of component (C), the weight percentage of component (D) and / or the weight percentage of component (E) is 100 weight %.

[0260] When the three-dimensional molded article comprises components (C) and (D), it therefore comprises, for example, 58.5% by mass to 99.75% by mass of component (A), 0.05% by mass to 1.5% by mass of component (B), 0.1% by mass to 5% by mass of component (C), 0.1% by mass to 5% by mass of component (D), and 0% by mass to 30% by mass of component (E), based on the total mass of the three-dimensional molded article.

[0261] Generally, component (A) is component (A) present in the sintered powder (SP), likewise, component (B) is component (B) present in the sintered powder (SP), component (C) is component (C) present in the sintered powder (SP), component (D) is component (D) present in the sintered powder (SP), and component (E) is component (E) present in the sintered powder (SP).

[0262] When step i-1) is performed, the three-dimensional shaped article further typically contains residual components of the fusing agent.

[0263] It is clear to the skilled artisan that as a result of exposure to light or heating of the sintered powder (SP), components (A), (B) and, optionally, (C), (D) and (E) may enter into chemical reactions and, as a result, change. Such reactions are known to the skilled artisan.

[0264] Preferably, components (A), (B), and optionally (C), (D) and (E) do not undergo a chemical reaction upon exposure to light in step ii); instead, the sintered powder (SP) simply melts.

Claims

1. The following components: (A) At least one thermoplastic polyurethane of 58.5% to 99.95% by mass based on the total of the mass percentages of (A), (B), (C), (D) and (E), (B) At least one flow agent of 0.05% to 1.5% by mass based on the total of the mass percentages of (A), (B), (C), (D) and (E), (C) At least one organic additive of 0% to 5% by mass based on the total of the mass percentages of (A), (B), (C), (D) and (E), (D) At least one further additive of 0% to 5% by mass based on the total of the mass percentages of (A), (B), (C), (D) and (E), and (E) At least one reinforcing agent of 0% to 30% by mass based on the total of the mass percentages of (A), (B), (C), (D) and (E) comprising a sintered powder (SP), wherein said at least one thermoplastic polyurethane (A) comprises at least the following components, (a) at least one isocyanate, (b) at least one isocyanate-reactive compound, and (c) at least one chain extender prepared by reacting, wherein components (a), (b) and (c) each contain an aromatic moiety of 15 mol% or less based on the total amount of each component (a), (b) and (c), and component (a) is selected from the group consisting of hexamethylene 1,6-diisocyanate (HDI) and dicyclohexylmethane 2,2'-diisocyanate (H12MDI), a sintered powder (SP).

2. The sintered powder (SP) according to claim 1, wherein said at least one flow agent (B) is selected from the group consisting of silicon dioxide, silicate, silica, metal oxide, mineral, borate, phosphate, sulfate, and carbonate, preferably from the group consisting of hydrophobic fumed silica, talc, kaolin, magnesium sulfate, calcium sulfate, barium sulfate, magnesium carbonate, calcium carbonate and barium carbonate.

3. i) In each case, based on the total of the mass percentages of (A), (B), (C), (D) and (E), 73.3% to 99.9% by mass, preferably 74.9% to 99.8% by mass, more preferably 75.4% to 99.75% by mass of component (A), and / or ii) In each case, based on the total mass percentages of (A), (B), (C), (D) and (E), component (B) in an amount of 0.1% to 1.2% by mass, preferably 0.2% to 1.1% by mass, more preferably 0.25% to 1.0% by mass, and / or iii) In each case, based on the total mass percentages of (A), (B), (C), (D) and (E), component (C) in an amount of 0% to 3% by mass, preferably 0% to 1.5% by mass, more preferably 0% to 1.1% by mass, and / or iv) Based on the total mass percentages of (A), (B), (C), (D) and (E), component (D) in an amount of 0% to 2.5% by mass, and / or v) Based on the total mass percentages of (A), (B), (C), (D) and (E), component (E) in an amount of 0% to 20% by mass The sintered powder (SP) according to claim 1, comprising the same.

4. The at least one organic additive (C) is selected from the group consisting of polyethylene wax, polypropylene wax, polypropylene wax grafted with maleic acid and / or maleic anhydride, amide wax, fatty acid ester and glycerin fatty acid ester, preferably selected from polypropylene wax grafted with maleic acid and / or maleic anhydride and amide wax, more preferably N,N'-alkylene fatty acid diamide. The sintered powder (SP) according to claim 1.

5. The sintered powder (SP) is i) having a particle size (D50) in the range of 10 to 150 μm, preferably in the range of 15 to 130 μm, more preferably in the range of 20 to 110 μm, particularly preferably in the range of 40 to 100 μm, and the particle size (D50) is determined by the laser diffraction method according to ISO 13320:2020-01, and / or ii) A melting temperature (T Ｍ（ＳＰ），Ｈ１ ), having a range of 90 to 220 °C, preferably a range of 100 to 190 °C, more preferably a range of 120 to 170 °C, and most preferably a range of 128 to 168 °C, Ｍ（ＳＰ），Ｈ１ ) being determined by a differential scanning calorimeter in accordance with DIN EN ISO 11357-3:2018-04, and / or iii) having a bulk density in the range of 250 to 700 g / L, preferably in the range of 280 to 600 g / L, more preferably in the range of 310 to 580 g / L, and the bulk density is determined according to DIN EN ISO 60:2000-01, and / or iv) produced by grinding, precipitation, melt emulsification or atomization The sintered powder (SP) according to claim 1.

6. As component (b), i) A polyol is used, wherein the content of the polyol that is not a polyether polyol is ≤ 15% by mass, preferably ≤ 5% by mass, more preferably ≤ 1% by mass, based on the total mass of the polyol, or ii) A polyol is used, wherein the content of the polyol that is not a polyester polyol is ≤ 15% by mass, preferably ≤ 5% by mass, more preferably ≤ 1% by mass, based on the total mass of the polyol. The sintered powder (SP) according to claim 1.

7. The sintered powder (SP) according to claim 1, wherein the at least one additional additive (D) is selected from the group consisting of an anti-nucleating agent, a stabilizer, a conductive additive, a terminal group functionalizing agent, a dye, an antioxidant, a flame retardant, and a coloring pigment.

8. The sintered powder (SP) according to claim 1, wherein the at least one reinforcing agent (E) is selected from the group consisting of carbon nanotubes, glass beads, and aluminum silicate, preferably from the group consisting of glass beads and aluminum silicate.

9. The following components: (A) At least one thermoplastic polyurethane of 58.5% to 99.95% by mass based on the total mass percentage of (A), (B), (C), (D), and (E), (B) At least one flow agent of 0.05% to 1.5% by mass based on the total mass percentage of (A), (B), (C), (D), and (E), (C) At least one organic additive of 0% to 5% by mass based on the total mass percentage of (A), (B), (C), (D), and (E), (D) At least one additional additive of 0% to 5% by mass based on the total mass percentage of (A), (B), (C), (D), and (E), and (E) At least one reinforcing agent of 0% to 30% by mass based on the total mass percentage of (A), (B), (C), (D), and (E) A method for producing a sintered powder (SP) comprising: The at least one thermoplastic polyurethane (A) is at least the following components, (a) At least one isocyanate, (b) At least one isocyanate-reactive compound, and (c) At least one chain extender Prepared by reacting, Components (a), (b), and (c) each contain an aromatic moiety of 15 mol% or less based on the total amount of each component (a), (b), and (c), The method is a) a step of pulverizing the total amount of component (A) based on the total mass of the sintered powder (SP) including wherein, based on the total mass of the sintered powder (SP), a first portion (BT1) of the total amount of component (B), and / or optionally, based on the total mass of the sintered powder (SP), a first portion (CT1) of the total amount of component (C) is mixed with component (A) before step a) to obtain a powder (P), and the remaining portion (BT2) of the total amount of component (B) and / or optionally, the remaining portion (CT2) of the total amount of component (C) is mixed with the powder (P) after step a) to obtain a sintered powder (SP), the first portion (BT1) occupies 0 to 100% by mass of the total amount of component (B) based on the total mass of the sintered powder (SP), the first portion (CT1) occupies 0 to 100% by mass of the total amount of component (C) based on the total mass of the sintered powder (SP), the remaining portion (BT2) occupies (100 - BT1)% by mass of the total amount of component (B) based on the total mass of the sintered powder (SP), and the remaining portion (CT2) occupies (100 - CT1)% by mass of the total amount of component (C) based on the total mass of the sintered powder (SP). Optionally, the total amount of component (D) based on the total mass of the sintered powder (SP), and / or the total amount of component (E) based on the total mass of the sintered powder (SP) is mixed before step a) or after step a), a method.

10. A method of using the sintered powder (SP) according to claim 1 in a three-dimensional (3D) printing process, preferably a sintering process, more preferably a selective laser sintering (SLS) process or a multi-jet fusion (MJF) process.

11. The following components (A) at least one thermoplastic polyurethane of 58.5% to 99.95% by mass based on the total of the mass percentages of (A), (B), (C), (D) and (E); (B) at least one flow agent of 0.05% to 1.5% by mass based on the total of the mass percentages of (A), (B), (C), (D) and (E); (C) at least one organic additive of 0% to 5% by mass based on the total of the mass percentages of (A), (B), (C), (D) and (E); (D) at least one further additive of 0% to 5% by mass based on the total of the mass percentages of (A), (B), (C), (D) and (E), and At least one reinforcing agent in an amount of 0% to 30% by mass based on the total mass percentages of (A), (B), (C), (D), and (E). A three-dimensional molded article comprising: The at least one thermoplastic polyurethane (A) comprises at least the following components: (a) At least one isocyanate, (b) At least one isocyanate-reactive compound, and (c) At least one chain extender Prepared by reacting, A three-dimensional molded article, wherein components (a), (b), and (c) each contain an aromatic moiety of 15 mol% or less based on the total amount of each component (a), (b), and (c).

12. The following steps: i) Providing a layer of the sintered powder (SP) according to Claim 1; ii) Exposing or heating the layer of the sintered powder (SP) provided in step i). A method for manufacturing a three-dimensional molded article, comprising:

13. A three-dimensional molded article obtained by the method according to Claim 12.

14. In a three-dimensional (3D) printing process for manufacturing a three-dimensional molded article, a method of using the sintered powder (SP) according to Claim 1 to improve the energy return of the three-dimensional molded article.

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