Shaped body, process for producing a shaped body and use of a powdered composition

Abstract

Use of a powdered composition in the production of a three-dimensional shaped body which is created layer by layer or by additive addition by selective sintering or melting, wherein the powdery composition contains at least one powder of a polyamide (PA), characterized in that the polyamide comprises a first polyamide (A) selected from the group consisting of PA5.9, PA5.10, PA5.11, PA5.12, PA5.13, PA5.14, PA6, PA6.66, PA6.9, PA6.10, PA10.9, PA10.10, PA10.12, PA12.9, copolymers and mixtures thereof, and where the PA powder has the following parameters: a melting temperature in the range of 180 to 240 °C, a melt flow index of 400 cm 3 / 10 min or less, measured at a temperature of 50 to 55 °C above the melting temperature, a melt flow index of 325 cm 3 / 10 min or less, measured at a temperature of 30 to 35 °C above the melting temperature, and a melt flow index of 250 cm 3 / 10 min or less, measured at a temperature of 10 to 15 °C above the melting temperature, each measured at a test load of 5 kg, and that the powdered composition has an elongation at break of at least 5.0% after sintering in the dry, unconditioned state.

Description

[0001] The invention relates to molded bodies produced by selectively sintering a powdered composition. Furthermore, the invention relates to a process for producing a molded body and the use of the powdered composition in the production of a molded body.

[0002] The rapid and cost-effective production of prototypes and series components using additive manufacturing processes has become a frequently encountered task in recent times. Particularly suitable are so-called "powder bed fusion" processes, which rely on powdered materials and produce the desired structures layer by layer through selective melting and delayed solidification. These processes are also suitable for small-batch production.

[0003] A particularly well-suited process for additive manufacturing or the production of small-batch components is powder bed fusion, such as the HP Multi Jet Fusion™ (MJF) process, high-speed sintering, or selective absorption fusion (SAF™). In these processes, plastic powders are selectively printed with a liquid absorber in a chamber and exposed to light across their entire surface, melting the powder particles covered with the absorber. The molten particles merge and quickly solidify into a solid mass. By repeatedly exposing newly applied layers to light for short periods, this process allows three-dimensional objects to be produced quickly and easily.

[0004] For high-speed sintering, the “HP Multi Jet Fusion™” process or the “Selective Absorption Fusion” (SAF™ process), plastic powders made of polyester, polyvinyl chloride, polyacetal, polypropylene, polyethylene, polystyrene, polycarbonate, poly-(N-methylmethacrylimide) (PMMI), polymethyl methacrylate (PMMA) and polyamide or mixtures thereof can be used.

[0005] In laser sintering (LS), another powder bed fusion process, a thin layer of powder is applied to a build platform and melted into the powder bed using a laser beam according to the layer contour of the desired component, with processing taking place layer by layer in a vertical direction.

[0006] EP 3 028 842 B1 discloses powdered compositions comprising at least one powder of a thermoplastic polypropylene (PP). The powder has a melting point in the range of 125 to 155 °C and a melt flow index at 160 °C (2.16 kg) in the range of 2 to 30 g / 10 min.

[0007] CN 110 305 335 A discloses a process for controlling the melt flow index of polyamide powders. In this process, a polyamide resin, together with a solvent and an auxiliary agent, is transferred into an autoclave and heated under an inert gas atmosphere to a temperature at which the polyamide completely dissolves in the solvent. After a certain holding time at this temperature, the solution is cooled back to room temperature, whereupon a polyamide with a higher melt flow index precipitates, which is filtered off and dried.

[0008] A crucial parameter for the quality of a component formed using powder bed fusion is its elongation at break. Elongation at break indicates the deformability of a material. Insufficient elongation at break results in brittle components that are not sufficiently suitable for many applications. Not all plastic powders that are generally suitable for use with powder bed fusion produce molded parts with sufficient elongation at break.

[0009] There is therefore still a need for plastic powders for use in powder bed fusion processes such as laser sintering, or in surface exposure processes such as the MJF process, high-speed sintering or selective absorption fusion, which enable the production of high-quality molded parts.

[0010] According to the invention, this object is achieved by the use of a powdered composition in the production of a shaped body according to claim 1.

[0011] Advantageous variants of the powdered composition according to the invention are specified in the subclaims, which can optionally be combined with one another.

[0012] The invention further relates to a method according to claim 10 for producing a shaped body using the powdered composition.

[0013] The invention further relates to a shaped body according to claim 11, produced according to the previously described use of the powdery composition.

[0014] The powdery composition contains at least one powder of a polyamide (PA) and is characterized in that the polyamide comprises a first polyamide (A) selected from the group consisting of PA5.9, PA5.10, PA5.11, PA5.12, PA5.13, PA5.14, PA6, PA6.66, PA6.9, PA6.10, PA10.9, PA10.10, PA10.12, PA12.9, copolymers and mixtures thereof, and wherein the PA powder has the following parameters: a melting temperature in the range of 180 to 240 °C, a melt flow index of 400 cm 3 / 10 min or less, measured at a temperature of 50 to 55 °C above the melting temperature, a melt flow index of 325 cm 3 / 10 min or less, measured at a temperature of 30 to 35 °C above the melting temperature, and a melt flow index of 250 cm 3 / 10 min or less, measured at a temperature of 10 to 15 °C above the melting temperature, each measured at a test load of 5 kg.

[0015] In addition, the powdered composition has an elongation at break of at least 5.0% after sintering in the dry, unconditioned state.

[0016] Above and below, the terms “powder made of a polyamide (PA)” and “PA powder” are used synonymously.

[0017] The melt flow index is a parameter for characterizing the viscosity of a plastic powder and is determined according to ISO 1133-1 and ISO 1133-2. The plastic powder to be tested is first oven-dried for at least 24 hours. Oven drying takes place at 80 °C in a vacuum or at 105 °C in circulating air. The measurement temperature is adjusted to the melting point of the plastic powder being tested. The melt flow index is determined as the average of at least three individual measurements. The melt flow index is defined here as the melt volume flow rate (MVR).

[0018] It was recognized that powdered compositions containing a PA powder of selected polyamides whose viscosity corresponds to a predetermined viscosity profile, as can be determined by measuring the melt flow index, are suitable for the production of high-quality molded articles in layer-by-layer production.

[0019] In particular, the viscosity profile is defined as a function of the melting temperature of the PA powder.

[0020] The melting temperature of the PA powder is defined here as the corresponding peak temperature of the DSC measurement (DSC: Differential Scanning Calorimetry) of the PA powder. The DSC measurement is carried out according to ISO 11357-1.

[0021] By limiting the melt flow index of the PA powders in the powdered compositions, the resulting components exhibit high surface quality and good edge sharpness. This eliminates the need for post-processing of the components, thus reducing production effort and costs.

[0022] Furthermore, after sintering in the dry, unconditioned state, the powdered composition, and thus a molded article or component produced from the powdered composition, exhibits a high elongation at break. In other words, the compositions according to the invention make it possible to obtain components with excellent mechanical properties by deliberately limiting the viscosity.

[0023] The term "dry, unconditioned state" here means that no water absorption has occurred after sintering of the powdered composition. In particular, the water content in the dry, unconditioned state is a maximum of 0.2 percent by weight, based on the total weight of the powdered composition after sintering.

[0024] The dry, unconditioned state can be achieved and maintained if, at the end of the production of the shaped body, it is cooled in the so-called powder cake under an inert gas atmosphere and is sealed in an air- and moisture-tight packaging immediately after removal from the powder cake.

[0025] The term “sintering” refers to the processing of the powdered composition in layer-by-layer production, for example by means of “powder bed fusion”, to form a shaped body, component or test specimen, whereby the PA powder of the powdered composition is completely melted layer by layer by supplying energy, optionally fused with an underlying layer and, after solidification of the melt, compacted to form an essentially pore-free body.

[0026] Elongation at break is determined according to ISO 527-1. The test speed for determining elongation at break is 5 mm / min. For determining elongation at break, the required test specimens (also called "tensile bars") can be produced directly from the powdered composition, for example, by selective laser sintering. The test specimens are manufactured according to ISO 3167 Type A or ISO 527-2 Type 1A.

[0027] The term "elongation at break" refers to the elongation at break in the build plane of the molded bodies or components produced from the powdered composition (also referred to as "elongation at break in x"). The term "elongation at break in z" is used for the elongation at break in the build direction. PA powder

[0028] Polyamides are polymers that have regularly repeating amide groups along their main chain. The amide group is an amide bond derived from a carboxylic acid and an amine. Polyamides are synthesized, technically usable thermoplastics. They can be derived from primary or secondary amines. Monomers used for polyamides include, for example, aminocarboxylic acids, lactams, polyethylene glycols, and / or diamines and dicarboxylic acids.

[0029] In principle, all polyamides are suitable for the powdery composition according to the invention which comprise the above-described first polyamide (A), have a melting temperature of 180 to 240 °C, have the required viscosity profile and, after sintering, have a sufficiently high elongation at break and, in particular, other desired properties, for example a desired modulus of elasticity and / or a desired strength.

[0030] The first polyamide (A) is selected from the group consisting of PA5.9, PA5.10, PA5.11, PA5.12, PA5.13, PA5.14, PA6, PA6.66, PA6.9, PA6.10, PA10.9, PA10.10, PA10.12, PA12.9, copolymers and mixtures thereof.

[0031] In particular, the first polyamide (A) is selected from the group consisting of PA5.9, PA5.10, PA5.11, PA5.12, PA5.13, PA5.14, PA6, PA6.10, PA10.10, copolymers and mixtures thereof.

[0032] In a preferred variant, the polyamide consists of the first polyamide (A).

[0033] In a further variant, the polyamide is a copolymer or a mixture of the first polyamide (A) and a second polyamide (B), wherein the first polyamide (A) is selected from the group consisting of PA5.9, PA5.10, PA5.11, PA5.12, PA5.13, PA5.14, PA6, PA6.66, PA6.9, PA6.10, PA10.9, PA10.10, PA10.12, PA12.9, copolymers and mixtures thereof and the second polyamide (B) is selected from the group consisting of PA4.6, PA4.10, PA5.6, PA6.6, PA6.12, PA6-3-T, PA6T, PA9T, PA6T.6, PA12T, PA66.6 copolymers and mixtures thereof.

[0034] In particular, the polyamide in this variant is a copolymer or a mixture of the first polyamide (A) and the second polyamide (B), wherein the first polyamide (A) is selected from the group consisting of PA5.9, PA5.10, PA5.11, PA5.12, PA5.13, PA5.14, PA6, PA6.10, PA10.10, copolymers and mixtures thereof and the second polyamide (B) is selected from the group consisting of PA4.6, PA4.10, PA5.6, PA6.6, PA6.12, PA6-3-T, PA6T, PA9T, PA6T.6, PA12T, PA66.6 copolymers and mixtures thereof.

[0035] If the polyamide is a copolymer or a mixture of a first polyamide (A) and a second polyamide (B), the first polyamide (A) is the main component in the copolymer or mixture.

[0036] The names used for the polyamides follow the notation commonly used in the state of the art for naming polyamides. Table 1 provides an overview of selected polyamides and the monomers required for their synthesis. Table 1: Overview of polyamide types. polyamide Monomers PA4.6 Tetramethylenediamine and adipic acid PA4.10 Tetramethylenediamine and 1,10-decanedioic acid PA5.6 Pentamethylenediamine and adipic acid PA5.9 Pentamethylenediamine and azealic acid PA5.10 Pentamethylenediamine and 1,10-decanedioic acid PA5.11 Pentamethylenediamine and aminoundecanoic acid PA5.12 Pentamethylenediamine and dodecanoic acid PA5.13 Pentamethylenediamine and brassylic acid PA5.14 Pentamethylenediamine and tetradecanoic acid PA6 ε-Caprolactam PA6.6 Hexamethylenediamine and adipic acid PA6.9 Hexamethylenediamine and azealic acid PA6.10 Hexamethylenediamine and 1,10-decanedioic acid PA6.12 Hexamethylenediamine and dodecanoic acid PA6.66 Adipic acid, ε-caprolactam and hexamethylenediamine PA6-3-T Trimethylhexamethylenediamine and terephthalic acid PA6T Hexamethylenediamine and terephthalic acid PA6T.6 Hexamethylenediamine, terephthalic acid and ε-caprolactam PA9T Nonyldiamine and terephthalic acid PA10.9 1,10-Decamethylenediamine and azealic acid PA10.10 1,10-Decamethylenediamine and 1,10-decanedioic acid PA10.12 1,10-Decamethylenediamine and dodecanoic acid PA10.13 1,10-Decamethylenediamine and brassylic acid PA12.9 1,12-Dodecanedioic acid and azealic acid PA12T 1,12-Dodecanedioic acid and terephthalic acid

[0037] Preferably, the first polyamide (A) is selected from the group consisting of PA6, PA10.10, copolymers and mixtures thereof.

[0038] In the powdery composition, the PA powder is preferably present in a proportion of at least 55 percent by weight, based on the total weight of the powdery composition, preferably in a proportion of at least 60 percent by weight.

[0039] The powdery composition may consist of PA powder.

[0040] In one variant, the PA powder has a melt flow index of 240 cm 3 / 10 min or less, measured at a temperature of 50 to 55 °C above the melting point, of 160 cm 3 / 10 min or less, measured at a temperature of 30 to 35 °C above the melting point, and of 100 cm 3 / 10 min or less, measured at a temperature of 10 to 15 °C above the melting point, each measured at a test load of 5 kg.

[0041] In this case, the first polyamide (A) is in particular selected from the group consisting of PA6, PA10.10, copolymers and mixtures thereof.

[0042] The polyamide can have a viscosity number in the range of 125 to 450 mL / g, measured according to ISO 307. To determine the viscosity number, a solution of the polyamide in 96% sulfuric acid (w / w) is used, with the polyamide used at a concentration of 0.005 g / mL. The measurement is carried out at 25 °C. Properties of the powdered composition

[0043] The following property profiles of the powdered composition refer to the powdered composition before the addition of fillers, unless otherwise stated.

[0044] The powdered composition according to the invention exhibits an elongation at break of at least 5.0% after sintering in the dry, unconditioned state. In particular, the powdered composition exhibits an elongation at break in the range of 5.0 to 100% after sintering, preferably 8 to 30%, particularly preferably 10 to 30%.

[0045] After sintering in the dry, unconditioned state, the powdered composition also has, in particular, an elongation at break in z of 3.0% or more.

[0046] In order to enable further improved mechanical properties, the powdered composition after sintering in the dry, unconditioned state may have an elastic modulus of 1500 MPa or more, in particular an elastic modulus in the range of 2000 to 4000 MPa, determined according to ISO 527-1.

[0047] In addition, the powdered composition after sintering in the dry, unconditioned state can have a strength in the range of 45 to 80 MPa, determined according to ISO 527-1.

[0048] For the determination of the modulus of elasticity and strength, the same test specimens according to ISO 3167 (Type A) or ISO 527-2 Type 1A are used as for the determination of the elongation at break.

[0049] Furthermore, the powdered composition may have a particle size in the range of 0.1 to 200 µm, preferably 0.1 to 125 µm. The particle size can be determined by sieve analysis according to DIN 66165-1 and DIN 66165-2, preferably using an air jet sieve.

[0050] The average particle size D 50 of the powdery composition is in particular in the range from 30 to 100 µm, preferably from 40 to 90 µm. Below the average particle size D 50This refers to the volume-related median of the particle size distribution, as it can be determined using dynamic image analysis according to ISO 13322-2.

[0051] The bulk density of the powdered composition is in particular at least 330 g / L, preferably the bulk density is 350 to 750 g / L. The bulk density is measured according to DIN EN ISO 60.

[0052] By using a powder composition with a high bulk density, denser molded bodies can be obtained after sintering compared to conventional plastic powders, which can promote the achievement of high elongation at break. Furthermore, a higher bulk density leads to improved flowability and improved dosability, simplifying the processing of the powder composition.

[0053] The powdered composition can be prepared by cold milling a thermoplastic polyamide (PA) to form a milled PA powder and sieving the milled PA powder to separate a sieve fraction of the PA powder.

[0054] For this purpose, a cast polyamide block or polyamide granulate can be cooled with liquid nitrogen and ground into a fine, powdery material using a mill. By sieving the powdery material after milling, a sieve fraction of the PA powder with a desired grain size distribution is obtained. Other components of the powdered composition

[0055] In addition to the PA powder, the composition used according to the invention may contain one or more of the following components.

[0056] The powdered composition may contain an antioxidant, in particular in a proportion of 0.05 to 10 percent by weight, based on the total weight of the powdered composition. The antioxidant can at least partially prevent degradation of the polymer chains of the polyamide during processing and / or storage and thus improve the mechanical properties of a molded article produced from the powdered composition. The antioxidant may be selected from the group consisting of aromatic amines, phenols, polyphenols, aliphatic hydrocarbons with two or more hydroxy groups, alkali bromides, phosphoric acids and phosphorous acids, including their esters and salts, copper complexes, other copper compounds, and combinations thereof.

[0057] Furthermore, the powdered composition may comprise a flow aid, in particular in a proportion of 0.01 to 10 percent by weight, based on the total weight of the powdered composition. Examples of flow aids that can be used include precipitated or fumed silica, carbon black, an aluminum oxide, an aluminum silicate, and / or other metal oxides.

[0058] To facilitate processing of the powdered composition, the powdered composition may contain a lubricant, particularly in a proportion of 0.05 to 15 percent by weight, based on the total weight of the powdered composition. Lubricants that can be used include polyolefin waxes, metal soaps, metal stearates, especially alkaline earth stearates, ester-containing complex compounds, fatty acid esters, and / or fatty acids with linear carbon chains.

[0059] In one variant, the powdered composition comprises a dye, particularly in a proportion of 0.05 to 5 percent by weight. During processing of polyamide-based compositions, brownish discolorations may occur, particularly at the temperatures required for processing. These discolorations can be at least partially offset by the added dye. Titanium dioxide, carbon black, and / or nigrosine, for example, can be used as dyes.

[0060] Furthermore, the powdered composition may comprise a flame retardant, in particular in a proportion of 0 to 40 percent by weight. The flame retardant is preferably halogen-free. Phosphinates, melamine, and / or melamine cyanurate can be used as flame retardants.

[0061] In addition, the powdered composition may contain one or more conventional fillers, particularly in a proportion of 0 to 40 percent by weight. Fillers may include, for example, glass beads, glass fibers, carbon fibers, wollastonite, kaolin, ceramics, or combinations thereof.

[0062] If both flame retardants and fillers are used in the powdered composition, these together have a proportion in the range of 0 to 60 percent by weight, based on the total weight of the powdered composition.

[0063] The additional components can be mixed or compounded into the powdered composition. Antioxidants and lubricants are preferably compounded.

[0064] In order to obtain a powdery composition that is as homogeneous as possible, the grain size of the additional components described above can preferably be in the range of the grain size of the PA powder.

[0065] In one variant, the composition consists of the PA powder and one or more of the previously described components.

[0066] Preferred embodiments of the powdered compositions are described below. Powdered compositions with PA 6

[0067] In a preferred variant, the first polyamide (A) is PA6. In particular, in this variant, the PA powder consists of the first polyamide (A).

[0068] The PA powder made of PA6 has in particular a melting temperature in the range of 200 to 240 °C, particularly preferably in the range of 215 to 225 °C.

[0069] In particular, the PA powder made from PA6 has a melt flow index of 240 cm 3 / 10 min or less, preferably 200 cm 3 / 10 min or less and particularly preferably 185 cm 3 / 10 min or less, measured at a temperature of 50 to 55 °C above the melting point and at a test load of 5 kg.

[0070] Furthermore, the PA powder made of PA6 has a melt flow index of 160 cm 3 / 10 min or less, preferably 130 cm 3 / 10 min or less and particularly preferably 110 cm 3 / 10 min or less, measured at a temperature of 30 to 35 °C above the melting point and at a test load of 5 kg.

[0071] In addition, the PA powder made from PA6 has a melt flow index of 100 cm 3 / 10 min or less, preferably 80 cm 3 / 10 min or less and particularly preferably 75 cm 3 / 10 min or less, measured at a temperature of 10 to 15 °C above the melting point and at a test load of 5 kg.

[0072] The PA powder made of PA6 has in particular a viscosity number in the range of 125 to 300 mL / g, preferably in the range of 130 to 265 mL / g.

[0073] The powdery composition used according to the invention with a PA powder made of PA6 has, after sintering in the dry, unconditioned state, in particular an elongation at break in the range of 5.0 to 100%, preferably in the range of 8 to 30%, particularly preferably in the range of 10 to 30%.

[0074] In addition, the powdered composition with a PA powder made of PA6 has, after sintering in the dry, unconditioned state, in particular a strength in the range of 50 to 80 MPa, preferably of 65 to 75 MPa.

[0075] The powdery composition with a PA powder made of PA6 has, after sintering in the dry, unconditioned state, in particular an E-modulus in the range of 2000 to 4000 MPa, preferably in the range of 2400 to 3700 MPa, particularly preferably in the range of 2800 to 3400 MPa.

[0076] The bulk density of the powdery composition with a PA powder made of PA6 is in particular at least 350 g / L, preferably the bulk density is from 400 to 650 g / L, particularly preferably the bulk density is from 400 to 550 g / L.

[0077] Additional components used in powdered compositions with a PA powder made from PA6 include, in particular, an antioxidant, a flame retardant and / or fillers. Powdered compositions with PA 10.10

[0078] In a preferred variant, the first polyamide (A) is PA10.10. In particular, in this variant, the PA powder consists of the first polyamide (A).

[0079] The PA powder made of PA10.10 has in particular a melting temperature in the range of 180 to 220 °C, particularly preferably in the range of 190 to 210 °C.

[0080] In particular, the PA powder from PA10.10 has a melt flow index of 150 cm 3 / 10 min or less, preferably 100 cm 3 / 10 min or less and particularly preferably 70 cm 3 / 10 min or less, measured at a temperature of 50 to 55 °C above the melting point and at a test load of 5 kg.

[0081] Furthermore, the PA powder made of PA10.10 has a melt flow index of 70 cm 3 / 10 min or less, preferably 50 cm 3 / 10 min or less and particularly preferably 35 cm 3 / 10 min or less, measured at a temperature of 30 to 35 °C above the melting point and at a test load of 5 kg.

[0082] In addition, the PA powder made from PA10.10 has a melt flow index of 40 cm 3 / 10 min or less, preferably 30 cm 3 / 10 min or less and particularly preferably 20 cm 3 / 10 min or less, measured at a temperature of 10 to 15 °C above the melting point and at a test load of 5 kg.

[0083] The PA powder made from PA10.10 has in particular a viscosity number in the range of 140 to 240 mL / g, preferably in the range of 160 to 220 mL / g.

[0084] The powdery composition used according to the invention with a PA powder made of PA10.10 has, after sintering in the dry, unconditioned state, in particular an elongation at break in the range of 5.0 to 20%, preferably in the range of 8 to 15%.

[0085] In addition, the powdered composition with a PA powder made of PA10.10 has, after sintering in the dry, unconditioned state, in particular a strength in the range of 50 to 70 MPa, preferably 50 to 60 MPa.

[0086] The powdery composition with a PA powder made of PA10.10 has, after sintering in the dry, unconditioned state, in particular an E-modulus in the range of 1500 to 3000 MPa, preferably in the range of 1800 to 2800 MPa, particularly preferably in the range of 2000 to 2500 MPa.

[0087] The bulk density of the powdery composition with a PA powder made of PA10.10 is in particular at least 350 g / L, preferably the bulk density is from 350 to 650 g / L, particularly preferably the bulk density is from 350 to 500 g / L.

[0088] The invention further relates to a process for producing a shaped body which operates on the basis of powdered materials using a powdered composition of the type described above, and in which the desired structures are produced layer by layer by selective sintering or melting.

[0089] In particular, the molded body is produced within a construction space which preferably has an atmosphere with an oxygen content of 1.0 volume percent or less.

[0090] The invention also relates to the use of a powdery composition of the type described above in the production of a shaped body which is produced layer by layer or by additive addition by selective sintering or melting.

[0091] Furthermore, the invention relates to shaped bodies produced by laser sintering, high-speed sintering, multi-jet fusion, selective absorption fusion or another powder bed fusion process, by a selective thermoplastic electrophotographic process or by another additive manufacturing process from a powdery composition of the type described above.

[0092] The shaped bodies according to the invention have in particular the mechanical properties previously described for the powdered composition after sintering in the dry, unconditioned state.

[0093] Further advantages and features of the invention will become apparent from the following description of exemplary embodiments, which, however, should not be understood in a limiting sense.

[0094] Previously and in the following, the abbreviation “MVR (x °C)” refers to the melt flow index in cm 3 / 10 min, measured at a temperature of x °C, with a test load of 5 kg and determined according to ISO 1133-1 and ISO 1133-2.

[0095] The specified value of elongation at break refers below to a tensile test specimen made from the respective powder composition according to ISO 3167, determined according to ISO 527-1.

[0096] The viscosity number is determined according to ISO 307. PA6 Table 2: Overview of powder compositions with PA6. Example polyamide Melting temperature in°C Viscosity number in mL / g Additional component 1.1 PA6 222 225 1.2 PA6 222 134 1.3 PA6 222 225 Phenol (antioxidant, compounded) 1.4 PA6 222 225 Antioxidant (copper complex, powder mixture) 1.5* Solvay 210 nb Sinterline 1.6* PA6 222 107 1.7* PA6 209 nb *: Comparative example, not according to the invention nb: not determined

[0097] No viscosity numbers were available for comparative examples 1.5 and 1.7. Table 3: Properties of the powder compositions from Table 2. Example MVR (235 °C) MVR(255 °C) MVR (275 °C) Elongation at break 1.1 11 19 33 10 - 30% 1.2 71 106 171 nb 1.3 18 47 145 10 - 21% 1.4 7 17 58 8 - 12% nb: not determined

[0098] The following values ​​were determined for comparative example 1.5 from Table 2: MVR (225 °C): 46 MVR (245 °C): 182 MVR (265 °C): 402

[0099] An elongation at break of 4.5% was measured on the test specimen prepared from Comparative Example 1.5.

[0100] The following values ​​were determined for comparative example 1.6 from Table 2: MVR (235 °C): 203 MVR (255 °C): 387 MVR (275 °C): 692

[0101] An elongation at break of 1 to 2% was measured on the test specimen prepared from Comparative Example 1.6.

[0102] The following values ​​were determined for comparative example 1.7 from Table 2: MVR (225 °C): 157 MVR (245 °C): 235 MVR (265 °C): 499

[0103] An elongation at break of 1.5 to 3.2% was measured on the test specimen prepared from Comparative Example 1.7

[0104] As shown in Table 3, test specimens with high elongation at break values ​​can be obtained from powdered compositions containing a PA powder made from PA6. In particular, high elongation at break values ​​can be achieved even without adding an antioxidant to the powdered composition.

[0105] The elastic modulus of the test specimens obtained in Examples 1.1 to 1.4 ranged from 2800 to 3300 MPa. The strength of the test specimens obtained ranged from 65 to 75 MPa.

[0106] The bulk density of the powdered compositions of Examples 1.1 to 1.4 was in the range of 420 to 550 g / L.

[0107] The commercially available product “Solvay Sinterline”, Comparative Example 1.6 with a material having a viscosity number of 107 mL / g, as well as Comparative Example 1.7 do not show the viscosity profile according to the invention and do not lead to test specimens with an elongation at break of at least 5.0%. PA10.10 Table 4: Overview of powder compositions with PA10.10. Example polyamide Melting temperature in °C Viscosity number in mL / g 2.1 PA10.10 200 160 2.2 PA10.10 200 180 2.3* PA10.10 190 nb *: Comparative example, not according to the invention nb: not determined Table 5: Properties of the powder compositions from Table 4. Example MVR(215 °C) MVR (235 °C) MVR(255 °C) Elongation at break 2.1 20 35 69 9 - 13% 2.2 10 22 35 nb nb: not determined

[0108] The following values ​​were determined for comparative example 2.3 from Table 4: MVR (205 °C): 110 MVR (225 °C): 197 MVR (245 °C): 443

[0109] An elongation at break of 2.3% was measured on the test specimen prepared from Comparative Example 2.3.

[0110] As shown in Table 5, test specimens with high elongation at break values ​​can be obtained from powdered compositions containing a PA powder made from PA10.10. In particular, high elongation at break values ​​can be achieved even without adding an antioxidant to the powdered composition.

[0111] The elastic modulus of the test specimens obtained in Examples 2.1 and 2.2 ranged from 2000 to 2500 MPa. The strength of the test specimens obtained ranged from 50 to 58 MPa. For the determination, several test specimens were produced from the same starting material in a series of measurements.

[0112] The bulk density of the powdered compositions of Examples 2.1 and 2.2 was in the range of 360 to 480 g / L.

Claims

[1] Use of a powdered composition in the manufacture of a three-dimensional shaped body which is created layer by layer or by additive addition by selective sintering or melting, wherein the powdery composition contains at least one powder of a polyamide (PA), characterized by , that the polyamide comprises a first polyamide (A) selected from the group consisting of PA5.9, PA5.10, PA5.11, PA5.12, PA5.13, PA5.14, PA6, PA6.66, PA6.9, PA6.10, PA10.9, PA10.10, PA10.12, PA12.9, copolymers and mixtures thereof, and where the PA powder has the following parameters: a melting temperature in the range of 180 to 240 °C, a melt flow index of 400 cm 3 / 10 min or less, measured at a temperature of 50 to 55 °C above the melting temperature, a melt flow index of 325 cm 3 / 10 min or less, measured at a temperature of 30 to 35 °C above the melting temperature, and a melt flow index of 250 cm 3 / 10 min or less, measured at a temperature of 10 to 15 °C above the melting temperature, each measured at a test load of 5 kg, and that the powdered composition has an elongation at break of at least 5.0% after sintering in the dry, unconditioned state. [2] Use according to claim 1, characterized by that the first polyamide (A) is selected from the group consisting of PA5.9, PA5.10, PA5.11, PA5.12, PA5.13, PA5.14, PA6, PA6.10, PA10.10, copolymers and mixtures thereof. [3] Use according to claim 1 or 2, characterized bythat the polyamide is a copolymer or a mixture of the first polyamide (A) and a second polyamide (B), wherein the second polyamide (B) is selected from the group consisting of PA4.6, PA4.10, PA5.6, PA6.6, PA6.12, PA6-3-T, PA6T, PA9T, PA6T.6, PA12T, PA66.6, copolymers and mixtures thereof. [4] Use according to one of the preceding claims, characterized by that the PA powder has a melt flow index of 240 cm 3 / 10 min or less, measured at a temperature of 50 to 55 °C above the melting point, of 160 cm 3 / 10 min or less, measured at a temperature of 30 to 35 °C above the melting point, and of 100 cm 3 / 10 min or less, measured at a temperature of 10 to 15 °C above the melting point, each measured under a test load of 5 kg. [5] Use according to one of the preceding claims, characterized bythat the powdered composition after sintering in the dry, unconditioned state has an elongation at break in the range of 5.0 to 100%. [6] Use according to one of the preceding claims, characterized by that the powdered composition has one or more of the following parameters: a particle size in the range of 0.1 to 200 µm, an average particle size D 50 in the range of 30 to 100 µm, a bulk density of at least 330 g / L. [7] Use according to one of the preceding claims, characterized by that the PA powder is present in a proportion of at least 55% by weight, based on the total weight of the powdered composition. [8] Use according to one of the preceding claims, characterized bythat the powdered composition comprises one or more of the following components: an antioxidant, a flow aid, a lubricant, a colorant, a filler, a flame retardant. [9] Use according to claim 8, characterized by that the powdered composition comprises one or more of the following components: an antioxidant in a proportion of 0.05 to 10 percent by weight, a flow aid in a proportion of 0.01 to 10 percent by weight, a lubricant in a proportion of 0.05 to 15 percent by weight, a dye in a proportion of 0.05 to 5% by weight, a filler in a proportion of 0 to 40 percent by weight, a flame retardant in a proportion of 0 to 40 percent by weight, each based on the total weight of the powdered composition. [10] A method for producing a shaped body based on powdered materials using a powdered composition, in which the shaped bodies are produced layer by layer by selective sintering or melting with a predetermined structure, wherein the powdery composition contains at least one powder of a polyamide (PA), characterized by , that the polyamide comprises a first polyamide (A) selected from the group consisting of PA5.9, PA5.10, PA5.11, PA5.12, PA5.13, PA5.14, PA6, PA6.66, PA6.9, PA6.10, PA10.9, PA10.10, PA10.12, PA12.9, copolymers and mixtures thereof, and where the PA powder has the following parameters: a melting temperature in the range of 180 to 240 °C, a melt flow index of 400 cm 3 / 10 min or less, measured at a temperature of 50 to 55 °C above the melting temperature, a melt flow index of 325 cm 3 / 10 min or less, measured at a temperature of 30 to 35 °C above the melting temperature, and a melt flow index of 250 cm 3 / 10 min or less, measured at a temperature of 10 to 15 °C above the melting temperature, each measured at a test load of 5 kg, and that the powdered composition has an elongation at break of at least 5.0% after sintering in the dry, unconditioned state. [11] Shaped body produced by selective sintering according to the use of a powdery composition according to any one of claims 1 to 9.