EP4413062A1

EP4413062A1 - Composition for an additive manufacturing process

Info

Publication number: EP4413062A1
Application number: EP22800136.8A
Authority: EP
Inventors: Andreas BÜCK; Maximilian DECHET; Sybille Fischer; Karl Freihart; Andreas Pfister; Jochen Schmidt; Jens SESSEG; Laura UNGER
Original assignee: EOS GmbH
Current assignee: EOS GmbH
Priority date: 2021-10-08
Filing date: 2022-09-30
Publication date: 2024-08-14
Also published as: DE102021126217A1; WO2023057337A1

Abstract

The present invention relates to a composition comprising at least one polymer, the polymer solidifying from a molten material in a substantially amorphous or completely amorphous form. The present invention further relates to a method for producing the composition according to the invention, to a structural component comprising a composition according to the invention and to the use of the composition according to the invention.

Description

Composition for additive manufacturing processes

The present invention relates to a composition comprising at least one polymer, the polymer solidifying from a melt in an essentially amorphous or completely amorphous form. Furthermore, the present invention relates to a method for producing the composition according to the invention and a component comprising a composition according to the invention and the use of the composition according to the invention.

Additive manufacturing processes for the production of prototypes and the industrial production of components that work on the basis of powdered materials enable the production of plastic objects and are constantly gaining in importance. In the manufacturing process, the desired structures are produced in layers by selective melting and solidification or by applying a binder and/or adhesive. The process is also known as "additive manufacturing", "digital fabrication" or "three-dimensional (3D) printing".

Methods in industrial development processes for the production of prototypes have been used for decades (rapid prototyping). Due to the technological progress of the systems, however, the production of parts that meet the quality requirements of an end product (rapid manufacturing) was also started.

In practice, the term "additive manufacturing" is often replaced by "generative manufacturing" or "rapid technology". Additive manufacturing processes that use a powdered material are, for example, sintering, melting or gluing with binders.

Polymer systems are often used as powdered materials for the production of shaped bodies. Industrial users of such systems require good processability, high dimensional stability and good mechanical properties from the moldings produced from them.

In the manufacture of 3D components, it is of great importance to achieve a layer connection in the melt with the underlying component layers, since interdiffusion between the layers can only take place in the melt. If insufficient Layer adhesion tends to delaminate 3D components in their final state and lose strength.

When manufacturing 3D components using Additive Manufacturing (AM), in particular using powder-bed-based AM processes, in which the powder is selectively solidified by the introduction of radiant energy, the installation space temperature must be above the crystallization temperature of the respective polymer on the one hand, and on the other hand the However, the temperature must be below the melting temperature, as otherwise the powder cake in the construction space would melt. In the context of powder bed-based additive manufacturing, a polymer powder is therefore usually heated to just below the melting temperature before the remaining energy required to melt the powder and achieve a sufficiently low melt viscosity is introduced using a radiation source. The temperature range between the crystallization temperature (TC) and the melting temperature (TM) is called the process window or the sintering window of the polymer. If the crystallization and melting of a polymer overlap to a significant extent on the temperature axis, then this polymer is most likely not accessible to the process, i. H. it does not have a sufficient process window.

It is therefore advantageous if a polymer has a melting temperature that is as high as possible, based on the crystallization temperature or the glass transition temperature, in order to enable a broadening of the process window or the sintering window.

It is therefore the object of the present invention to provide an improved composition which is preferably suitable in additive manufacturing processes as a material for the production of shaped bodies with process-reliable processing, mechanical stability and high dimensional stability. In particular, it is an object of the present invention to provide an improved composition which has a larger process window, in particular a higher melting temperature.

This object is achieved according to the invention by a composition according to claim 1. Furthermore, the object is achieved by a method for producing the composition according to claim 9, by a method for producing a component according to claim 14 and by using the composition according to claim 18 according to the invention. The present invention therefore relates to a composition, in particular as a construction material for an additive manufacturing process as mentioned above, comprising at least one polymer, the polymer being in the form of polymer particles and the polymer being selected from at least one thermoplastic polymer,

- wherein the at least one thermoplastic polymer solidifies from a melt in at least essentially amorphous or completely amorphous form and can be represented in this way,

- that a melting temperature of the polymer is at least 280 °C, preferably at least 290 °C, preferably at least 300 °C, and/or wherein a melting temperature of the material is up to 400 °C, preferably up to 375 °C , particularly preferably up to 350 ° C, and / or

- that a specific enthalpy of fusion of the polymer is at least 28 J/g, preferably at least 30 J/g, preferably at least 35 J/g, and/or wherein a specific enthalpy of fusion of the material is up to 150 J/g, preferably up to 125 J /g, preferably up to 100 J/g.

In its simplest embodiment, a composition according to the invention comprises at least one thermoplastic polymer, where the thermoplastic polymer solidifies from a melt in an essentially amorphous or completely amorphous form. The determination of such a thermoplastic polymer is known to the person skilled in the art and can be carried out, for example, by means of differential scanning calorimetry (DSC).

A polymer is considered to be “essentially amorphous or solidifying in a completely amorphous form” if, at a heating rate of 20 K/min and a cooling rate of 5 K/min, it has a specific enthalpy of fusion in the 2nd heating run of < 1 J/g, measured by DSC according to DIN EN ISO 11357-1 (3:2018-07).

The composition according to the invention is preferably in the form of a powder.

Surprisingly, the melting temperature of a material obtained in this way is at least 280.degree. C., preferably at least 290.degree. C., preferably at least 300.degree. At most, however, the melting temperature of the material is up to 400°C, preferably up to 375°C, particularly preferably up to 350°C. Advantageously, such a high melting temperature of the composition can bring about an expansion of the process window. The term "melting temperature" is understood to mean the temperature at which a substance melts, i.e. changes from the solid to the liquid state of aggregation. In the present case, the terms “melting temperature” and “melting point” are used synonymously. If a composition has several melting peaks, the melting temperature is the peak temperature of the most prominent peak. Methods for determining the melting temperature are known to those skilled in the art and can usually be measured using differential scanning calorimetry (DSC) in accordance with DIN EN ISO 11357 (3:2018-07).

According to the invention, a high melting temperature allows heating to higher temperatures and thus lower energy input from the radiation source, which significantly reduces the probability of degradation of the polymer during exposure.

The viscosity lowered with the melt is advantageous for good flow of the melt, as a result of which denser components with fewer pores with improved mechanical properties and a high component density can be obtained. The high melting temperature also means that less energy has to be introduced by the laser in order to heat the polymer up to a sufficiently low viscosity at which good flow of the melt and thus good layer bonding is possible.

In addition, the composition according to the invention has a specific enthalpy of fusion of the material of at least 28 J/g, preferably at least 30 J/g, preferably at least 35 J/g. At most, the specific enthalpy of fusion of the composition is up to 150 J/g, preferably up to 125 J/g, preferably up to 100 J/g. Such an advantageous composition enables better delimitation of the component from non-sintered powder, since as a result fewer powder particles adjoining the component are melted. Furthermore, such an advantageous melting enthalpy can result in a higher construction temperature and thus an extended process window.

The term “enthalpy of fusion” or “specific enthalpy of fusion” is understood to mean the amount of energy required to melt a substance sample at its melting temperature at constant pressure (isobar), i.e. from the solid to the to transfer liquid state of aggregation. Methods for determining the enthalpy of fusion are known to those skilled in the art; for example, the enthalpy of fusion can be measured using DSC in accordance with DIN EN ISO 11357 (3:2018-07).

Within the scope of the invention, the melting point Tm and the specific enthalpy of melting or crystallization AH of the materials used were determined by means of DSC measurements in accordance with the standard DIN EN ISO 11357 (3:2018-07). The melting point corresponds to the peak temperature of the melting peak occurring in the DSC curves. The measurements were carried out on a "Mettler Toledo DSC823e" type DSC device with an automatic sample changer. The evaluations were carried out with the software "STARe Software", version 16.30. Nitrogen 5.0, i.e. nitrogen with a purity of 99.999 percent by volume, was used as the purge gas. Using DSC, a sufficiently broad temperature range was examined for each material (e.g. the range from 0 °C to 400 °C for the PEI material examined). The heating and cooling rate was 20 K/min with a holding time of 5 min before each heating or cooling run.

Furthermore, the composition according to the invention ensures a homogeneous powder structure, so that improved flowability or pourability and thus a uniform powder input is made possible in the course of additive manufacturing processes. A bulk solid has good flowability if the bulk solid can be made to flow easily. Methods for determining flow or pourability are known to those skilled in the art. In addition to other parameters, the flowability or pourability of the powder can be determined, for example, with the aid of the flow factor (ff _c ) and the compressive strength (unconfined yield strength, UYS) (according to ASTM D6773-16).

The at least one thermoplastic polymer which solidifies from a melt in at least essentially amorphous or completely amorphous form is preferably obtainable by means of precipitation (syn. precipitation) from a first agent or a mixture of a first and at least one further agent. In the present case, the terms “obtainable”, “representable” and “manufacturable” are used synonymously.

Such a first and/or further agent is preferably selected from at least one organic agent, preferably from an organic, moderate solvent, for the at least one polymer. Under the designation "moderate solvent" is present a To understand non-solvent for the polymer, in which the polymer does not or only slightly dissolves at room temperature, so that the dissolved fraction of the polymer is less than 5 wt .-%. At temperatures above room temperature, on the other hand, it acts as a solvent, so that at least 5% by weight of the polymer is in dissolved form. In the following, the terms “moderate solvent” and “solvent” are used synonymously.

In the present patent application, a polymer or a polymer system or polymer material is understood to mean at least one homopolymer and/or one heteropolymer which is made up of a plurality of monomers. While homopolymers have a covalent linkage of the same monomers, heteropolymers (also called copolymers) are made up of covalent linkages of different monomers. A polymer system according to the present invention can include both a mixture of the abovementioned homo- and/or heteropolymers and more than one polymer system.

The terms polymer, polymer system and polymer material are used synonymously below.

Heteropolymers within the meaning of the present invention can be selected from random copolymers, in which the distribution of the two monomers in the chain is random, from gradient copolymers, which are similar in principle to the random copolymers, but in which the proportion of one monomer in the course of the chain increasing and decreasing the other, from alternating copolymers, in which the monomers alternate alternately, from block or segmented copolymers, made up of longer sequences or blocks of each monomer, and from graft copolymers, in which blocks of one monomer are attached to the skeleton (backbone) of another monomer are grafted.

The composition according to the invention can be used advantageously for additive manufacturing processes. Additive manufacturing processes include, in particular, methods that are suitable for producing prototypes (rapid prototyping) and components (rapid manufacturing), preferably from the group of powder-based manufacturing methods, particularly preferably powder-bed-based methods including laser sintering, high-speed sintering, binders Jetting, multi-jet fusion, selective mask sintering, selective laser melting or LaserProFusion. Solidification preferably takes place by Exposure to electromagnetic radiation. In particular, however, the composition according to the invention is intended for use in laser sintering or LaserProFusion. The term “laser sintering” is synonymous with the term “selective laser sintering” (SLS).

Furthermore, the present invention relates to a method for producing a composition according to the invention, the method comprising at least the following steps:

(i) providing at least one polymer material, wherein the polymer material is selected from at least one thermoplastic polymer,

(ii) Bringing together, in particular mixing, the polymeric material with a moderate solvent, preferably at a first temperature, wherein the moderate solvent does not dissolve the at least one polymer at the first temperature or dissolves it to no more than 5% by weight and wherein the moderate Solvent at a second temperature that is higher than the first temperature, the one polymer at least partially, preferably to more than 70% by weight, preferably to more than 80% by weight, more preferably to more than 90% by weight , particularly preferably more than 95% by weight, in particular more than 98% by weight, particularly preferably more than 99% by weight, most preferably more than 99.9% by weight,

(iii) heating the resulting polymer-solvent mixture, preferably with stirring, at least up to the second temperature in order to at least partially dissolve the polymer in the solvent,

(iv) maintaining the polymer-solvent mixture isothermally at least at the second temperature, preferably for a period of 15 minutes and with stirring,

(v) cooling the polymer-solvent mixture, preferably with stirring, preferably at least to a third temperature to precipitate the polymer from the solvent, and

(vi) obtaining the powdered material.

Advantageously, with the aid of the process according to the invention, a composition can be obtained which has a polymer melting point of at least 280° C., preferably at least 290° C., preferably at least 300° C. At most, the melting temperature of the composition is up to 400°C, preferably up to 375°C, particularly preferably up to 350°C.

Furthermore, such a composition has a specific enthalpy of fusion of the polymer of at least 28 J/g, preferably of at least 30 J/g, preferably of at least 35 J/g. At most, the specific enthalpy of fusion of the composition is up to 150 J/g, preferably up to 125 J/g, preferably up to 100 J/g.

“Providing” is understood to mean both production on site and delivery of a polymer or a polymer material.

The term "bringing together" according to step ii) above stands for "bringing into contact".

In the following, the terms "mixing" and "admixing" are understood to be synonymous. A process of mixing or admixing can take place in the disperser and/or in the stirrer and may include process operations such as melting, dispersing, etc.

The polymer material is preferably brought together or mixed with the moderate solvent at a first temperature, the moderate solvent not dissolving the at least one polymer at the first temperature, i. H. is not a solvent for the polymeric material and wherein the moderate solvent at a second temperature higher than the first temperature at least partially dissolves the polymer, i. H. is a solvent for the polymeric material.

In principle, the mixture of the polymer material and the moderate solvent can be heated to a temperature above or below a glass transition temperature of the at least one polymer or polymer material. The mixture of the polymeric material and the moderate solvent is preferably heated to a temperature above the glass transition temperature of the polymeric material. The term “glass transition temperature” is to be understood as meaning the temperature at which a polymer changes to a rubbery to viscous state. The determination of the glass transition temperature is known to the person skilled in the art and can be carried out, for example, by means of DSC in accordance with DIN EN ISO 11357 (2:2020-08).

The first temperature is preferably room temperature, the second temperature is preferably in a range from 60° C. below the glass transition temperature to 100° C. above the glass transition temperature, preferably at 70° C. above the glass transition temperature of the polymer; a third temperature is preferred below the glass transition temperature, preferably at 130° C. below the glass transition temperature, particularly preferably at 5° C. below the glass transition temperature.

The third temperature is preferably below the second temperature. The second and the third temperature are dependent on the set polymer loading and can be determined, for example, by creating a cloud point diagram. For this purpose, the polymer is brought together with the moderate solvent in a specific ratio in a high-pressure, high-temperature cell (e.g. PDE-140-LL, from Eurotechnica) and the system is heated until the polymer is visually completely dissolved in the agent (temperature gradient 9 K/ minutes); this temperature is kept constant for 15 minutes. During the subsequent continuous cooling with a temperature gradient of −2 K/min, preferably −1.5 K/min, the temperature at which clouding of the system begins is determined visually. The third temperature is below that cloud point for that very ratio of polymer to moderate solvent.

After the polymer has completely precipitated out (i.e. no further turbidity is visually detectable), the system is heated again with a constant temperature gradient of 9 K/min and the temperature at which turbidity is no longer visually detectable is determined. The second temperature is above that particular temperature for that very ratio of polymer to moderate solvent.

Preferably, the mixture of polymer and moderate solvent is heated with stirring in a closed vessel, preferably without pressure equalization. In particular, the pressure corresponds to the vapor pressure of the moderate solvent at the working temperature. Optionally, an additional pressurization, for example with inert gases, can take place here.

Subsequent cooling of the mixture preferably takes place to at least a third temperature in order to precipitate the polymer from the solvent in a controlled manner. Cooling can optionally take place with the introduction of shearing forces, for example by stirring. In this way, the particle size distribution can be influenced or specifically adjusted. Purification of the polymer preferably also takes place by means of such a production process. Such a purification step leaves low molecular weight components (VOC: volatile organic compounds and/or residual monomers, dimers, trimers, etc.), which are in the polymer material in accordance with step i) above, after cooling and precipitation in accordance with step v). Solvent dissolved. As a result, the powdery material obtained in this way according to step vi) has a higher degree of purity and has a lower concentration of these components.

After the purification, preferably at least 1% by weight of the VOC, particularly preferably 5% by weight of the VOC, in particular 10% by weight of the VOC, are dissolved in the solvent. At most 100% by weight of the VOC is dissolved in the solvent.

Such a purification step particularly preferably takes place with the addition of acetophenone as a solvent.

Such low-molecular components can have a disruptive effect in the process of manufacturing the component above certain concentrations. For example, by outgassing from the non-powdery material during the layer-by-layer construction process in the process chamber and separating again in the device or system for additive manufacturing in colder areas, thus leading to contamination of the manufacturing system, in particular the laser window. This can be associated with a loss of laser power over the overall height. Such low-molecular-weight components can also lead to outgassing during the melting of the powdery material and thus lead to higher porosity in the component.

Insofar as the composition according to the invention is packaged, a packaging process can advantageously be carried out in the absence of moisture or under controlled moisture, in order to avoid electrostatic charging of the powder, for example.

A composition produced according to the method according to the invention is advantageously used as a solidifiable powder material in a method for the layer-by-layer production of a three-dimensional object from the powdery material, in which successive layers of the object to be formed from this solidifiable powder material are successively attached to corresponding or predetermined ones Points are solidified by the entry of energy, preferably electromagnetic radiation, in particular by the entry of laser light.

The present invention also includes a composition, in particular for laser sintering processes, which can be obtained or is obtained using the process described above.

Finally, a composition according to the invention is used to produce a component, in particular a three-dimensional object, by applying in layers and selectively solidifying a construction material, preferably a powder. The term "solidification" is to be understood as at least partial melting or melting with subsequent solidification or resolidification of the building material.

An advantageous method for producing a component has at least the following steps:

(i) applying a layer of a composition according to the invention and/or a composition produced by a method according to the invention, preferably a powder, to a construction site,

(ii) selective solidification of the applied layer of the composition at locations corresponding to a cross section of the object to be produced, preferably by means of an irradiation unit, and

(iii) Lowering the carrier and repeating the steps of applying and solidifying until the component, in particular the three-dimensional object, is completed.

In the present patent application, “construction material” is understood to mean a powder or a solidifiable powder material, which can be solidified into shaped bodies or 3D objects by means of additive manufacturing processes, preferably by means of powder bed-based processes, in particular by means of laser sintering or laser melting. The composition according to the invention is particularly suitable as such a building material.

A plane that is located on a carrier within a machine for additive manufacturing at a certain distance from an irradiation unit that is mounted above it and is suitable for solidifying the construction material serves as the construction field. On The building material is positioned on the carrier in such a way that its top layer corresponds to the plane that is to be solidified. The carrier can be adjusted in the course of the manufacturing process, in particular laser sintering, in such a way that each newly applied layer of the construction material is at the same distance from the irradiation unit, preferably a laser, and can be solidified in this way by the action of the irradiation unit.

A component which has been produced from the composition according to the invention is advantageously present in at least essentially amorphous or completely amorphous form. Such a component is characterized in that at a heating rate of 20 K/min it has a specific enthalpy of fusion of less than 5 J/g, preferably less than 2 J/g, in particular less than 1 J/g, measured by DSC according to DIN EN ISO 11357-3:2018-07.

A component, in particular a 3D object, which was produced from the composition according to the invention also has advantageous tensile strength and elongation at break. The tensile strength characterizes the maximum mechanical tensile stress that can occur in the material. The determination of the tensile strength is known to the person skilled in the art and can be determined according to DIN EN ISO 527, for example. The elongation at break characterizes the deformability of a material in the plastic range (also called ductility) up to breakage and can be determined, for example, using DIN EN ISO 527-2.

Furthermore, a component which has been produced from the composition according to the invention has improved dimensional accuracy and/or less component distortion. Dimensional accuracy means that the actual dimensions of a workpiece are within the agreed permissible deviation or tolerance from the specified nominal dimension. The term also describes the resistance of a material, for example with regard to expansion and shrinkage. Common causes of dimensional changes are, for example, temperature, compressive or tensile forces, aging and moisture.

A component, in particular a three-dimensional object, which is produced from the composition according to the invention preferably has a density (according to DIN ISO 1183) of more than 1.15 g/cm ³ , preferably more than 1.20 g/cm ³ preferably more than 1.23 g/cm ³ , in particular more than 1.26 g/cm ³ and particularly preferably more than 1.29 g/cm ³ . Such a component has a maximum density of 1.40 g/cm ³ , preferably not more than 1.35 g/cm ³ , particularly preferably not more than 1.30 g/cm ³ . The above values preferably apply to a component that is made from a polymer or a composition without fillers.

According to a further preferred embodiment, an advantageous component, in particular a three-dimensional object, has a porosity of less than 10%, preferably less than 5%, particularly preferably less than 3%, in particular less than 2%, particularly preferably less than 1%. The determination of the porosity of components is known to the person skilled in the art and can be measured, for example, via the density of the three-dimensional objects produced in accordance with DIN ISO 1183 (according to Archimedes' principle) on a scale (Kern, type 770-60) with a Satorius YDK 01 density determination set .

The present invention also includes a component which can be obtained or is obtained using the method described above.

The composition according to the invention can be used both in rapid prototyping and in rapid manufacturing. Here, for example, additive manufacturing processes, preferably from the group of powder-based processes, particularly preferably from the group of powder-bed-based processes (including laser sintering, LaserProFusion, high-speed sintering, multi-jet fusion, binder jetting, selective mask Sintering, selective laser melting), in particular for use in technologies that solidify the material by means of electromagnetic radiation, optionally with the aid of absorbers, more preferably for use in laser sintering or in the LaserProFusion process. This process can advantageously be used to produce prototypes or production parts in a time- and cost-efficient manner.

"Rapid manufacturing" refers in particular to processes for the production of components, i.e. the production of more than one identical part, but in which the production z. B. using an injection mold is not economical or not possible due to the geometry of the component, especially if the parts have a very complex design. Examples of this are parts for high-quality cars, racing or rally vehicles, which are only produced in small numbers, or spare parts for motor sports, for which the time of availability plays a role in addition to the small numbers. Industries in which the parts of the invention are used, for. B. the aerospace industry, medical technology, mechanical engineering, the Automobile construction, the sports industry, the household goods industry, the electronics industry and lifestyle. Also important is the production of a large number of similar components, for example personalized components such as prostheses, (inner ear) hearing aids and the like, the geometry of which can be individually adapted to the wearer.

Finally, the present invention includes a composition as solidifiable powder material in a method for the layer-by-layer production of a three-dimensional object from powdery material, in which successive layers of the object to be formed from this solidifiable powder material are successively solidified at corresponding points by the input of energy, preferably by the Entry of electromagnetic radiation, in particular through the entry of laser light.

Further particularly advantageous configurations and developments of the invention result from the dependent claims and the following description, the patent claims of a specific category can also be developed according to the dependent claims of another category and features of different exemplary embodiments can be combined to form new exemplary embodiments.

According to a preferred embodiment, an advantageous composition comprises a thermoplastic polymer which is selected from at least one polyetherimide, polycarbonate, polyarylethersulfone, polyphenylene oxide, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-styrene-acrylate copolymer, polyvinyl chloride, polyacrylate, polyester, polyamide, Polyaryl ether ketone, polyether, polyurethane, polyimide, polyamideimide, polyolefin, polyarylene sulfide, polysiloxane and their copolymers and/or at least one polymer blend based on the aforementioned polymers and/or copolymers.

The thermoplastic polymer is preferably selected from at least one polyetherimide, a polyarylethersulfone and/or from at least one polymer blend made from at least one polyetherimide and/or a polyarylethersulfone and at least one other polymer.

The at least one polymer is preferably selected from at least one homo- and/or heteropolymer and/or from a polymer blend, the at least one homo- and/or heteropolymer particularly preferably being an amorphous homo- and/or Includes heteropolymer. A polymer blend preferably comprises at least two amorphous homo- and/or hetero-polymers or at least one partially crystalline and at least one amorphous homo- and/or hetero-polymer. The polymer blend particularly preferably contains at least two amorphous homo- and/or heteropolymers.

In particular, the at least one homo- and/or heteropolymer and/or polymer blend is selected from at least one amorphous polymer or an amorphous copolymer or a partially crystalline polymer blend composed of at least one partially crystalline polymer and at least one further amorphous polymer or an amorphous polymer blend composed of at least two amorphous polymers.

In the present case, the term “partially crystalline” is to be understood as meaning a substance which contains both crystalline and amorphous areas. A polymer is considered to be partially crystalline in particular if it is not amorphous and is less than 100%, preferably less than 99%, crystalline.

The heteropolymer or copolymer preferably has at least two different repeating units.

A composition according to the invention preferably comprises a polymer and/or a copolymer and/or a polymer blend with a melting point of up to 335.degree. C., preferably up to 330.degree. C., preferably up to 325.degree. A preferred polymer has a melting temperature of at least 285°C, more preferably at least 300°C, more preferably at least 310°C, more preferably at least 320°C, particularly preferably at least 323°C, particularly preferably about 324° C on. Insofar as the term "at least approximately" or "at most approximately" or "up to approximately" (etc.) is used in connection with the melting temperature, this means that the numerical value mentioned has a possible deviation of ± 2 °C may have.

In particular, the term "approximately" or "roughly" in this document designates the exact values in this or other text passages.

More preferably, a composition has an enthalpy of fusion of up to about 150 J/g, preferably of up to about 100 J/g, preferably of up to about 50 J/g, particularly preferably of up to about 38 J/g. At least the composition has a Enthalpy of fusion of at least about 28 J/g, preferably at least about 30 J/g, particularly preferably at least about 32 J/g, particularly preferably at least about 33 J/g, more preferably at least about 34 J/g and/or 35 J/g, most preferably about 36 J/g. Insofar as the term "at least approximately" or "at most approximately" or "up to approximately" (etc.) is used in connection with the enthalpy of fusion, this means that the numerical value mentioned may deviate by ± 5% can.

Such melting temperatures and enthalpies of fusion are particularly preferred for PEI.

According to a preferred composition, the thermoplastic polymer is selected from at least one polyetherimide. The polyetherimide particularly preferably has repeating units according to

Formula I and / or repeating units according to

Formula II and / or repeating units according to

Formula III on. The number n of repeating units of the formulas I, II and III is preferably at least 10 and/or up to a maximum of 1000. The polyetherimide preferably has repeating units of the formula III.

The molecular weight of such a polyetherimide is preferably at least 5000 μm, preferably at least 10,000 μm, particularly preferably at least 15,000 μm and/or at most 200,000 μm, in particular at least 15,000 μm and/or at most 100,000 μm. The weight average molecular weight of such a preferred polymer is preferably at least 20,000 µ, more preferably at least 30,000 µ and/or at most 500,000 µ, especially at least 30,000 µ and/or at most 200,000 µ.

A preferred polyetherimide according to formula I is available, for example, under the trade names Ultern® 1000, Ultern® 1010 and Ultern® 1040 (Sabic, Germany). A preferred polyetherimide according to formula III is available, for example, under the trade names Ultern® 5001 and Ultern® 5011 (Sabic, Germany).

According to a preferred composition, the thermoplastic polymer is selected from at least one polyarylethersulfone. It is particularly preferably a polyether sulfone (PESU), polysulfone (PSU) and/or polyphenylene sulfone (PPSU) of the following structural formulas:

The number n of repeating units is preferably at least 10 and/or up to a maximum of 1000.

The molecular weight of such a polyarylethersulfone is preferably at least 5000 μm, preferably at least 10,000 μm, particularly preferably at least 15,000 μm and/or at most 200,000 μm, in particular at least 15,000 μm and/or at most 100,000 μm. The weight average molecular weight of such a preferred polymer is preferably at least 20,000 µ, more preferably at least 30,000 µ and/or at most 500,000 µ, especially at least 30,000 µ and/or at most 200,000 µ.

A preferred polyarylethersulfone is available, for example, under the trade name Ultrason® (BASF, Germany). A preferred polyethersulfone is available, for example, under the trade name Ultrason® E2010 (BASF, Germany). A more preferred composition comprises a polymer blend comprising a polyaryletherketone-polyetherimide, preferably a polyetherketoneketone, particularly preferably a polyetherketoneketone with a terephthalic acid isophthalic acid isomer ratio of between 65:35 and 55:45. A preferred composition can be a polyetherimide, which preferably contains the repeating units of the formula I contains have.

Finally, a preferred composition can have a polycarbonate, in particular with the repeating unit of formula IV:

Formula IV

As explained above, the composition can be obtained by means of precipitation from a first moderate solvent or a mixture of the first and at least one other moderate solvent. According to a preferred embodiment, the at least one or more moderate solvent is selected from at least one cyclic moderate solvent, such as lactams, phenones, phenols, cycloalkanes and/or cycloalkanones. Preferably the moderate solvent is selected from a homocyclic moderate solvent such as benzene, cyclohexanone, acetophenone, phthalic acid ester and/or a heterocyclic moderate solvent such as thiophenes and/or cyclic ethers, more preferably an aromatic homocyclic moderate solvent such as acetophenone , dimethyl phthalate and/or benzene, especially from an aromatic non-halogenated homocyclic moderate solvent.

With regard to the selection of a suitable moderate solvent, the Hansen solubility parameter can be used. The Hansen solubility parameter ÖT can be calculated with the formula ÖT ² = ÖD ² + öp ² + ÖH ² or by using the HSPiP software (Dr. techn. Charles M. Hansen, Jens Bornosvej 16, 2970 Horsholm, Denmark or via www.hansen-solubility .com) will be charged. In the present case, the terms “Hansen solubility parameter” and “solubility parameter” are used synonymously. According to a preferred embodiment, the moderate solvent has a solubility parameter that is at least 10 MPa ^1/2 lower, preferably at least 8 MPa ^1/2 lower, preferably at least 5 MPa ^1/2 lower and/or at most 10 MPa ^1/2 higher, preferably at most 8 MPa ^1/2 higher, preferably at most 5 MPa ^1/2 higher than a solubility parameter of the at least one polymer. In particular, the solubility parameters of the moderate solvent and the polymer are at least substantially the same. The term “substantially” in this case means that the solubility parameter of the moderate solvent and the solubility parameter of the polymer differ by no more than 10 MPa ^1/2 , preferably by no more than 8 MPa ^1/2 , more preferably by no more than 6 MPa ^1/2 , in particular by no more than 5 MPa ^1/2 .

The at least one or more moderate solvent is particularly preferably selected from dimethyl phthalate and/or acetophenone.

According to a further preferred embodiment, an advantageous composition comprises at least one auxiliary, the auxiliary being preferably selected from an additive and/or a filler.

The additive is preferably selected from the group of heat stabilizers, oxidation stabilizers, UV stabilizers, dyes, plasticizers, IR absorbers, SiÜ2 particles, carbon black particles, inorganic and/or organic pigments and/or flame retardants (especially phosphate-containing flame retardants such as red phosphorus, ammonium polyphosphate and/or brominated flame retardants and/or other halogenated flame retardants and/or inorganic flame retardants such as magnesium hydroxide or aluminum hydroxide).

The group of fillers preferably includes reinforcing fibers, SiO2 particles, metal oxides, calcium carbonate, carbon fibers, glass fibers, carbon nanotubes, mineral fibers (e.g. wollastonite), aramid fibers (especially Kevlar fibers), glass beads and/or mineral fillers.

Other preferred excipients include polysiloxanes. Polysiloxanes can be used, for example, as flow aids to reduce the viscosity of the polymer melt and/or as plasticizers, particularly in the case of polymer blends. The content of an auxiliary in the composition according to the invention can preferably be at least 0.01% by weight and/or at most 90% by weight, preferably at least 0.01% by weight and/or at most 50% by weight. -%.

For additives such as oxidation stabilizers, UV stabilizers or dyes, the content is preferably at least 0.01% by weight and/or at most 5% by weight, in particular at least 0.01% by weight and/or at most 2 wt%. For IR absorbers, the content is preferably at least 0.01% by weight and/or at most 1% by weight, preferably at least 0.01% by weight and/or at most 0.5% by weight , particularly preferably at least 0.02% by weight and/or at most 0.2% by weight, in particular at least 0.02% by weight and/or at most 0.1% by weight.

The content of a filler in the composition according to the invention can preferably be at least about 1% by weight and/or at most about 90% by weight, preferably at least 5% by weight and/or at most 50% by weight. , particularly preferably at least 10% by weight and/or at most 40% by weight.

Polymer systems often have a positive and/or negative partial charge. Particularly when particles of the polymer system have different charges at different points on the surface, interactions can occur, for example due to electrostatic, magnetic and/or van der Waals forces, between adjacent particles, which result in undesirable agglomeration of the polymer system particles .

According to a further preferred embodiment, an advantageous composition therefore comprises at least one anti-agglomeration agent. The term “anti-agglomeration agent” is a synonym for the term “flow aid”. In the present patent application, an anti-agglomeration agent is understood to mean a substance in the form of particles which can be deposited on and/or in the polymer particles.

"Accumulation" is understood to mean that particles of the anti-agglomeration agent enter into, for example, electrostatic forces, chemical bonds (e.g. ionic and covalent bonds) and hydrogen bonds and/or magnetic forces and/or van der Waals forces with particles of the polymer or of the polymer system interact and come into relative spatial proximity to each other in such a way that Particles of the polymer system advantageously do not come into direct contact with one another, but are separated from one another by particles of the anti-agglomeration agent. The polymer system particles that are spatially separated in this way generally develop little or no interaction with one another, so that the addition of anti-agglomeration agents advantageously counteracts clumping of the composition.

According to a preferred embodiment, an advantageous composition therefore comprises at least one anti-agglomeration agent. Such an anti-agglomeration agent can be selected from the group of metal soaps, preferably from a silicon dioxide, stearate, tricalcium phosphate, calcium silicate, aluminum oxide, magnesium oxide, magnesium carbonate, zinc oxide or mixtures of the like.

According to a further preferred embodiment, a first anti-agglomeration agent comprises silicon dioxide. This can be pyrogenic silicon dioxide produced by a wet-chemical precipitation process. However, the silicon dioxide is particularly preferably pyrogenic silicon dioxide.

In the present patent application, a pyrogenic silicon dioxide is understood to mean silicon dioxide which has been produced according to known methods, for example by flame hydrolysis by adding liquid tetrachlorosilane to the hydrogen flame. In the following, silicon dioxide is also referred to as silicic acid.

According to a further preferred embodiment, a composition according to the invention has a second anti-agglomeration agent and thus advantageously enables improved tuning of the physical properties, for example with regard to the electrostatic, magnetic and/or van der Waals forces of the anti-agglomeration agent, to the or the Polymer / s and thus improved processability of the composition, especially in laser sintering processes.

According to a particularly preferred embodiment, the second anti-agglomeration agent is also a silicon dioxide, in particular pyrogenic silicon dioxide. Of course, a composition according to the invention can also have more than two anti-agglomeration agents.

In an advantageous composition, a preferred proportion of the at least one anti-agglomeration agent is at most 1% by weight, more preferably at most 0.5% by weight, particularly preferably at most 0.2% by weight, in particular at most 0. 15% by weight, particularly preferably at most 0.1% by weight. The proportion relates to the proportion of all anti-agglomeration agents contained in the advantageous composition.

In principle, the at least one or the two or more anti-agglomeration agents can be treated with one or more different hydrophobing agents. According to a further preferred embodiment, the anti-agglomeration agent has a hydrophobic surface. Such hydrophobing can be done, for example, with a substance based on organosilanes.

Furthermore, the anti-agglomeration agent can advantageously effectively prevent caking and thus agglomeration of particles of the polymer system in the composition and counteracts the formation of cavities during pouring, as a result of which the bulk density of the composition is also advantageously increased. The bulk density can be influenced by its particle size or particle diameter and particle properties.

The term "bulk density" refers to the ratio of the mass of a granular solid, which was compacted by pouring and not by ramming or shaking, for example, to the bulk volume taken up. The determination of the bulk density is known to the person skilled in the art and can be carried out, for example, according to DIN EN ISO 60:2000-01.

A particularly advantageous composition has a bulk density of at least 350 kg/m ³ and/or at most 700 kg/m ³ . The bulk density here relates to the composition according to the invention.

Powders with a relatively round grain shape are required for the additive manufacturing processes explained above, since the presence of angular particles can result in scoring when the powder layers are applied, which makes an automatic construction process in particular more difficult is and the quality of the resulting components is deteriorated, in particular their density and surface quality. However, there is often the problem of obtaining polymers or copolymers in the form of a powder with round particles.

The composition according to the invention advantageously makes it possible to obtain round particles.

In general, an appropriate grain size or grain size distribution, a suitable bulk density and sufficient flowability of the powder material are important for compositions that are used in laser sintering processes.

The term grain size describes the size of individual particles or grains in a total mixture. The grain or particle size distribution has an influence on the material properties of a bulk material, ie the entire granular mixture, which is in a pourable form, for example in a powdery composition.

According to a further preferred embodiment, the particles of an advantageous composition have a grain size distribution

d10=at least 10 μm, preferably at least 15 μm and/or at most 50 μm, preferably at most 40 μm

d50=at least 20 μm and/or at most 100 μm, preferably at least 30 μm and/or at most 80 μm, particularly preferably at least 30 μm and/or at most 60 μm

- d90 = at least 35 pm and/or at most 150 pm, preferably at most 120 pm.

Methods for determining the grain size or the grain size distribution are known to those skilled in the art. For example, a measurement can be carried out on the Camsizer XT device and the X-Jet module (Retsch Technology GmbH) with the associated CamsizerXT64 software (version 6.6.11.1069). The optical methods for determining grain size and particle shape are based on the ISO 13322-2 standard. The sample of about 2 g is dispersed with 30 kPa compressed air and guided through a 4 mm wide passage past a calibrated optics unit with two cameras with different magnifications ("Basic" and "Zoom"). At least 10,000 individual images are recorded for evaluation. To ensure good visual separation of the considered To ensure particles, images are only used if the areal density of the particles shown is less than 3% (“Basic” camera) or less than 5% (“Zoom” camera). The particle sizes and shapes are determined using defined measurement parameters. The size determined is the equivalent diameter of the circle of equal area of the particle projection x_area=>/(4A/TT). The meridian or mean value of this evaluation method is comparable with laser diffraction (specified as d10, d50 and d90, ie as 10% quantile, 50% quantile and 90% quantile of the volumetric particle size distribution). The measurement is repeated several times to form statistical measured values.

According to a preferred embodiment, an advantageous composition has a distribution width (d90-d10)/d50 of at most 3, preferably at most 2, particularly preferably at most 1.5, in particular at most 1.

Another preferred composition has a proportion of fines, ie a proportion of particles with a particle size of less than 10 μm, of less than 10% by weight, preferably less than 6% by weight, in particular less than 4% by weight.

The polymer particles of the composition according to the invention preferably have an at least essentially spherical to lenticular configuration or shape. The polymer particles of a particularly advantageous composition particularly preferably have a sphericity of at least 0.7, preferably at least 0.8, in particular at least 0.85. The sphericity can be determined, for example, with the aid of microscopy (according to DIN ISO 13322-1) and/or a measuring device of the Camsizer XT type (Retsch Technology, Germany) according to DIN ISO 13322-2.

It has also proven to be advantageous for the particles of a composition according to the invention to have the smallest possible surface area. The surface can be determined, for example, by gas adsorption according to the principle of Brunauer, Emmet and Teller (BET); the standard used is DIN EN ISO 9277. The particle surface area determined using this method is also referred to as the BET surface area.

According to a preferred embodiment, the BET surface area of an advantageous composition is at least 0.1 m ² /g, preferably at least 0.5 m ² /g, particularly preferably at least 1 m ² /g. A BET surface area of a preferred composition is at most 20 m ² /g, particularly preferably at most 10 m ² /g, in particular at most 5 m ² /g, particularly preferably at most 3 m ² /g. In this case, a preferred BET surface area is at least 0.5 m ² /g and/or up to 2 m ² /g.

A method for producing an advantageous composition, in particular a powdered material, comprises at least one of the following steps in addition to the steps already explained above:

(a) Addition of at least one first excipient to the polymer or the polymer-solvent mixture according to step ii) or iii) above, and/or

(b) Addition of at least one first auxiliary and/or anti-agglomeration agent to the powdered polymer material.

In principle, the additive can therefore be added to the polymer-solvent mixture in accordance with step (a) above, or the additive and/or the anti-agglomeration agent can be added to the powdered polymer material in accordance with step (b). However, the at least one first auxiliary is preferably added to the polymer or to the polymer/solvent mixture in accordance with step (a) mentioned above. For example, the adjuvant can be added by compounding, i. H. by admixing the auxiliary substance(s) (for example in the extruder) to achieve desired property profiles.

According to a further preferred embodiment, the auxiliary is selected in such a way that it does not dissolve in the solvent but rather in the polymer. Such a procedure favors the fact that the auxiliary substance is present in the grain after the precipitation process.

Alternatively or additionally, the at least one first auxiliary can be added to the powdered polymer material in accordance with step (b). The at least one first auxiliary substance is preferably added to the powdered material after the powder has been produced, i. H. after removing the solvent and, if necessary, after drying the powder.

If one or more anti-agglomeration agents are added, they are added to the pulverulent material, as described above, according to step (b). Such an addition preferably takes place after the solvent has been removed and, if appropriate, after the powder has been dried. According to a preferred method, the polymer-solvent mixture comprises at least 1% by weight of the at least one thermoplastic polymer, preferably at least 5% by weight, preferably at least 10% by weight. The preferred polymer-solvent mixture contains at most 50% by weight, preferably at most 40% by weight, preferably at most 30% by weight, more preferably at most 25% by weight, in particular at most 20% by weight, particularly preferably at most 15% by weight of the at least one thermoplastic polymer.

A particularly preferred method of preparing a composition or powdered material uses a moderate solvent selected from at least one non-halogenated aromatic moderate solvent.

Additionally or alternatively, a preferred moderate solvent has a Hansen solubility parameter of at least 15 Æ, preferably at least 20 Æ, and/or at most 35 Æ, preferably at most 30 Æ, particularly preferably about 25 Æ.

Such a moderate solvent is particularly preferably selected from at least dimethyl phthalate and/or acetophenone.

In particular, the powdery material or the thermoplastic polymer is a polyimide, preferably a polyetherimide or a polyarylethersulfone.

In a further preferred method for producing an advantageous composition, the polymer-solvent mixture is cooled, in particular from a second temperature to a third temperature, in such a way that the polymer-solvent mixture cools down in a targeted or controlled manner. Cooling preferably takes place at a cooling rate of at least 0.05° C./min, preferably at least 0.1° C./min, particularly preferably at least 0.5° C./min, in particular at least 1° C./min, in particular preferably of at least 1.5° C./min. At most, cooling takes place at a rate of preferably 4° C./min, preferably at most 3° C./min, in particular at most 2° C./min.

The mixture can be cooled, for example, in a reactor, such as an autoclave, which is optionally equipped with a stirrer, and/or via a water / air cooling distance take place, which can extend over a few meters. A stirring process can take place passively by convection or actively by stirring the mixture.

In the further course, the polymer or the polymer particles are separated from the mixture and, if appropriate, the separated polymer or the polymer particles are washed and dried.

The components of the mixture are preferably separated off by centrifugation and/or filtration. Drying the solid component to obtain the dried composition can e.g. B. in an oven, for example in a vacuum dryer.

As already explained above, an additive can be added to the composition according to the invention in a next step. In particular, such an additive is selected from an anti-agglomeration agent. The additive, in particular an anti-agglomeration agent, is preferably added in a mixer.

Finally, an advantageous manufacturing method can provide packaging of the composition. Packaging of a composition produced by the method according to the invention, in particular sieved polymer particles, which are preferably in the form of a powder, is preferably carried out with the exclusion of atmospheric moisture, so that subsequent storage of the composition according to the invention can take place under reduced humidity to avoid caking effects, for example. whereby the storage stability of the composition according to the invention is improved. An advantageous packaging material also prevents moisture, in particular atmospheric moisture, from entering the composition according to the invention.

As mentioned above, compositions according to the invention are suitable for additive manufacturing processes, in particular for laser sintering processes. The target environment, for example the powder bed of the irradiation unit, in particular the laser beam, is usually heated before it is used, so that the temperature of the powder starting material is close to its melting temperature and even a small amount of energy input is sufficient to increase the total energy input to such an extent that the particles coalesce or solidify with one another. You can also energy-absorbing and/or energy-reflecting substances are applied to the target environment of the irradiation unit, which enable selective melting of the material at the points to be solidified.

As already explained above, according to the advantageous method, a three-dimensional object is selectively solidified by solidifying the composition according to the invention at predetermined locations by means of electromagnetic rays which are emitted by a radiation source.

A further embodiment relates to a system for the production of a three-dimensional object by solidifying the composition according to the invention at predetermined points, the system comprising at least one radiation source for emitting electromagnetic radiation. The system further includes a process chamber in the form of an open container having a wall, a support located within the process chamber, the process chamber and support being vertically movable relative to one another, a horizontally movable storage chamber and a Coater, wherein the storage chamber is at least partially filled with the composition of the invention.

According to a preferred embodiment, the radiation source emits light of a wavelength in the range from 500 nm to 1500 nm, preferably in the range from 1064±8 nm and/or 980±7 nm and/or 940±7 nm and/or 810±7 nm and/or or 640 ± 7 nm. Alternatively, the radiation source may emit light at a wavelength of about 10.6 pm or in the range of 4.8 pm to 8.3 pm, preferably in the range of 5 pm.

The radiation source preferably includes at least one laser, in particular a diode laser.

“Fusing” is understood to mean the process in which the powder is at least partially melted during an additive manufacturing process, for example in the powder bed, by introducing energy, preferably by means of electromagnetic waves, in particular by laser energy. The composition according to the invention and the method according to the invention ensure at least partial melting and process-reliable production of shaped bodies with high mechanical stability and dimensional stability. According to a preferred embodiment, the Composition according to the invention or the method according to the invention requires complete melting.

It has also been shown that the tensile strength, the modulus of elasticity and the elongation at break of an advantageous component can be useful as material properties or as a measure of the processability of the composition according to the invention.

According to a further preferred embodiment, an advantageous component which has been produced from a composition according to the invention, in particular a composition comprising a polyetherimide or a polyarylethersulfone, has a tensile strength parallel to the layer direction of at least 40 MPa, preferably at least 60 MPa, particularly preferably at least 70 MPa , In particular of at least 80 MPa, particularly preferably of at least 90 MPa. The preferred composition has a maximum tensile strength parallel to the layer direction of 200 MPa, preferably not more than 150 MPa, in particular not more than 100 MPa.

Furthermore, an advantageous component produced from a polymer or a composition without fillers, in particular a polymer or a composition comprising a polyetherimide or a polyarylethersulfone, still has a modulus of elasticity parallel to the layer direction of at least 1400 MPa, preferably at least 2000 MPa more preferably at least 2400 MPa, in particular at least 2800 MPa and very particularly greater than 3000 MPa. The preferred composition has a modulus of elasticity parallel to the layer direction of at most 5000 MPa, preferably at most 4000 MPa, in particular at most 3500 MPa.

Furthermore, an advantageous component has an elongation at break, which is preferably produced from a composition comprising a polyetherimide or a polyarylethersulfone, parallel to the layer direction of at least 1%, particularly preferably at least 3%, in particular at least 5%, particularly preferably at least 7%. on. A preferred component has an elongation at break of at most 100%, more preferably at most 80%, particularly preferably at most 50%, in particular at most 25%. The determination of the tensile strength, the modulus of elasticity and the elongation at break can be determined using the so-called tensile test according to DIN EN ISO 527 (2:2019-12) and is known to the person skilled in the art. Furthermore, the composition according to the invention can be measured in the cold or warm state in the laser sintering system, its layer application and powder bed state in the cold or warm state, its layer application in the laser sintering process, preferably in the ongoing laser sintering process, in particular its coating on exposed surfaces and the dimensional accuracy and the mechanical properties of the test specimens obtained are evaluated.

Furthermore, it can be advantageous if the composition comprises at least one auxiliary which allows the mechanical, electrical, magnetic, flame-retardant and/or aesthetic properties of the powder or product to be adjusted. In a preferred embodiment, the composition comprises at least one organic and/or inorganic auxiliary such as glass, metal, for example aluminum and/or copper and/or iron, ceramic particles, metal oxides or pigments to vary the color, preferably titanium dioxide or soot.

Alternatively or additionally, the excipient can also consist of a fiber, such as a carbon, glass and/or mineral fiber, such as e.g. B. wollastonite, be selected. This can also influence the absorption behavior of the powder. Fillers for adjusting the mechanical properties can also be selected from the group of metal oxides or from calcium carbonate. Flame retardant additives can for example be selected from the group consisting of metal hydroxides such as magnesium hydroxide or aluminum hydroxide, phosphorus compounds such. B. Red phosphorus or ammonium polyphosphate or brominated flame retardants.

Furthermore, it can be advantageous if the composition comprises at least one auxiliary which is used for thermo-oxidative stabilization of the polymer and/or for UV stabilization. It can be z. B. be an antioxidant and / or a UV stabilizer. Such an antioxidant can be obtained, for example, under the trade name Irganox or Irgafos from BASF (Ludwigshafen, Germany); a UV stabilizer can be obtained, for example, under the trade name Tinuvin from BASF.

Furthermore, it can be advantageous if an IR absorber is used as the auxiliary substance, which absorbs in the range of the wavelength used for the laser or infrared heating. This can be soot, for example. Further features of the invention result from the following description of exemplary embodiments in conjunction with the claims. It should be noted that the invention is not limited to the embodiments of the described embodiments but is to be determined by the scope of the appended claims. In particular, the individual features in embodiments according to the invention can be implemented in a different combination than in the examples given below. In the following explanation of some exemplary embodiments of the invention, reference is made to the attached figure. Show it:

1: DSC thermograms of a composition according to the invention (according to V1) comprising polyetherimide (PEI, Ultem CRS5011, Sabic).

2: DSC thermograms of a composition according to the invention (according to V2) comprising polyetherimide (PEI, Ultem CRS5011, Sabic).

Fig. 3: Top view of the placement of the components in the installation space (according to V1 and V2).

Fig. 4: Orthogonal view of the components (according to V1 and V2).

5: DSC thermograms of a composition according to the invention (according to V3) comprising polyetherimide (PEI, Ultem CRS5001, Sabic).

6: DSC thermograms of a composition according to the invention (according to V4) comprising polyetherimide (PEI, Ultem CRS5001, from Sabic).

7: DSC thermograms of a composition according to the invention (according to V5) comprising polyetherimide (PEI, Ultem CRS5011, Sabic).

8: DSC thermograms of a comparative example (according to V6) comprising

Polyetherimide (PEI, Ultem CRS5011, Sabic).

9: DSC thermograms of a comparative example (according to V7) comprising

Polyetherimide (PEI, Ultem CRS5011, Sabic). examples

Examples V1 and V2:

300 g of polyetherimide (PEI, trade name Sabic Ultem CRS5011, Sabic) were mixed with 1700 g of moderate solvent (corresponds to a loading of 15% by weight) in an autoclave (Versoklav 3, Büchi AG with 3L capacity and integrated stirrer, designed up to 200 bar and 300° C.) and heated to a temperature of 260° C. with stirring (V1: 350 rpm stirrer speed; V2: 500 rpm stirrer speed), the polymer dissolving in the solvent. The resulting pressure corresponds to the vapor pressure of the solvent. The solution was then cooled down to 60° C. at a speed of 350 rpm (V1) or 500 rpm (V2) with a temperature gradient over time of −1.5 K/min, with the polymer being produced as a powder the solution fails. The solvent was separated off by filtration and the polymer powder was washed with ethanol and at 120° C. in a vacuum oven (VT 6130 P, Thermo Scientific, Thermo Electron LED GmbH, equipped with a vacuum pump MD 12H from Vacuubrand GmbH & Co KG) ( 85 mbar pressure) dried for at least 48 hours.

The Hansen solubility parameter of the polymer is 28.9 MPa ^1/2 , those of the solvents dimethyl phthalate and acetophenone are 24.2 MPa ^1/2 and 21.2 MPa ^1/2 .

The determination of the flow factor and the compressive strength (unconfined yield strength, UYS) was carried out with a Schulze ring shear cell RST 01.01 (Dr. Dietmar Schulze bulk material measurement technology, D6773-16), with consolidation stresses 01 of about 1200 Pa, 2400 Pa and 4600 Pa on the sample were applied. Depending on 01, a uniaxial yield point o _c results. The quotient of the two parameters is defined as the flow function ff _c and is classified into five levels: ffc < 1 non-flowing

1 < ffc < 2 very cohesive

2 < ff _c < 4 cohesive

4 < ffc < 10 easy flowing

10 < ffc free flowing

The conditioned bulk density (CBD) was determined using an FT4 Powder Rheometer (Freeman Technology Ltd). The CBD was prepared according to the manufacturer's specifications [cf. Handbook W7008, Compressibility, Issue B, Freeman Technology Support Document, January 2006], measured with 60-65 g sample and a conditioning time > 24h.

Under the conditions mentioned above, a fine powder with a particle size distribution well suited for the laser sintering process could be obtained both from dimethyl phthalate and from acetophenone (see Table 1, below).

When dimethyl phthalate was precipitated, a powder with an average particle size (D50) of 29.6 pm (distribution width 0.66) was obtained, which has a melting point of 317.8 °C and a specific enthalpy of fusion of 42.8 J/g ( see Figure 1, upper curve; if DSC measurements are shown in the following examples, the first heating run is shown at the top, the second heating run is shown in the middle and the cooling run is shown at the bottom). A compressive strength of 904 Pa and an ff _c of 4.8, determined using a Schultze ring shear cell, shows that the powder is very easy to pour (see Table 1, below).

The BET surface area of the powder obtained from the precipitation with dimethyl phthalate was determined in accordance with DIN EN ISO 9277 by means of gas adsorption according to the Brunauer, Emmet and Teller (BET) principle. A value of 2.37 m ² /g was obtained.

A powder with a melting point of 286.2 °C and an enthalpy of fusion of 34.4 J/g could be precipitated from acetophenone (see FIG. 89) is also well suited for the laser sintering process. The powder is not only free-flowing (UYS of 1094 and ff _c of 4.0), but also has a comparatively high conditioned bulk density of 0.563 g/cm ³ (see Table 1, below). The conditioned bulk density is usually very close to the bulk density determined according to DIN EN ISO 60 and can be easily compared.

The BET surface area of the powder obtained from the precipitation with acetophenone was determined in accordance with DIN EN ISO 9277. A value of 1.12 m ² /g resulted.

The absence of a crystallization peak and a melting peak in the second heating run (see FIGS. 1 and 2, middle and bottom curve) shows that the originally crystalline material solidifies completely or at least essentially amorphously. Table 1: Melting temperature, specific enthalpy of fusion, particle size distribution, conditioned bulk density, compressive strength and the flow factor of the powdered material according to the invention. na = not available

Mechanical properties of the tensile specimens:

Tensile test specimens with the geometry DIN EN ISO 527-2 Type 1 BA in XYZ orientation were built on an EOS P810 with a reduced installation space (manufacturer: AMCM GmbH, Starnberg). The default job corresponds to that for the material HT-23 (EOS default job for the material HT-23 from Advanced Laser Materials, TX, USA; ALM_HT23-A_120_003), the layer thickness is 120 pm. The bulk energy input of the custom exposure parameters is given in the table below.

As can be seen in FIG. 3, the components were placed on the construction site. The components produced using the method according to the invention and their arrangement in relation to one another are shown in FIG. The labeling visible in the graphic is used to later distinguish between the test specimens.

The maximum tensile strength, the modulus of elasticity and the elongation at break were determined according to DIN EN ISO 527-2:2012-06 with the tensile bar geometry type 1 BA. A suitable condition for determining tensile strength, modulus of elasticity and elongation at break was in the dry state, with the test taking place a maximum of 3 hours after the components had been unpacked. According to DIN ISO 291, a temperature of 23 ± 2 °C and a relative humidity of 50 ± 10% are used as the preferred test climate for determining the mechanical properties. The test speed was 2 mm/min.

The density of the three-dimensional objects produced was measured according to Archimedes' principle in accordance with ISO 1183 on a scale (Kern, type 770-60) using a Satorius YDK 01 density determination set. The powder from V1 could be installed at a construction space temperature of 280 °C with a volume energy input of 0.208 J/mm ³ . In the tensile test, the resulting tensile test specimens showed a maximum tensile strength of 62.6 MPa with a modulus of elasticity of 2470 MPa and an elongation at break of 3.4%.

The powder from V2 was installed due to the lower melting point of 265°C installation space temperature and a volume energy input of 0.229 J/mm ^3. The resulting tensile test specimens showed a maximum tensile strength of 67.5 MPa with a modulus of elasticity of 2184 MPa and an elongation at break of 5.4%. The component density in both tests was 1.249 g/cm ³ (C1) and 1.244 g/cm ³ (C2). Since amorphous PEI has a density of 1.27 g/cm ³ , this value shows that dense components with low porosity of 1.7% or 2% were produced.

In particular, the components generated from the powder according to V1 and V2 according to the invention have, compared to components made of PEI, such. B. in WO2018197577A1, test series V26, significantly higher tensile strengths.

Table 2: Tensile specimen preparation conditions and mechanical property measurement.

From examples V1 and V2 it is evident that the partially crystalline PEI powder with a melting temperature of approx. 318° C. and 286° C. and a melting enthalpy of approx. 43 J/g and 34 J/g has a significantly higher melting temperature at the same time have a high enthalpy of fusion in comparison to the examples known from the literature (WO 2018/197577 A1, V1-9) and the examples V6 and V7 not according to the invention. The powders could thus be installed at process chamber temperatures of 280°C or 265°C, which leads to a complete and homogeneous fusion of the polymer particles without burning them. The components built in this way have a high degree of dimensional accuracy. Examples V3 and V4:

5 g of polyetherimide (PEI, trade name llltem CRS5001, Sabic) were mixed with 95 g of moderate solvent (corresponds to a loading of 5% by weight) in an autoclave (laboratory steel autoclave with PTFE inserts, type DAB-3, Berghof with 250 mL capacity and designed for up to 200 bar and 250 °C, magnetic stirring bar with a length of 25 mm and a diameter of 6 mm) and heated to a temperature of 250 °C with stirring (600 rpm stirrer speed), whereby the polymer dissolved in the medium. The resulting pressure corresponds to the vapor pressure of the solvent. The solution was then cooled down to 60° C. at a speed of 100 rpm with an average temperature gradient over time of −2 K/min, with the polymer precipitating out of the solution as a powder. The removal of the agent and the drying were carried out analogously to V1 and V2. Analogously to C1 and C2, the more viscous PEI variant could also be obtained as a crystalline fine powder by precipitation both from dimethyl phthalate (C3) and from acetophenone (C4).

With a melting temperature of 282.9° C. and a melting enthalpy of 32.1 J/g (V3, see FIG. 5) or 281.3° C. and 33.9 J/g (V4, see FIG. 6). the two powders have comparable thermal properties to the powder generated in V2. The mean particle size (D50) for the powder generated in V3 is 50.6 μm (distribution range 0.58) and for the powder generated in V4 it is 79.4 μm (distribution range 1.35), which are typical values for laser sintering powders that can be used well (see Table 3, below).

In FIGS. 5 and 6, similar to V1 and V2, no melting peak (middle curve in each case) or crystallization peak (lower curve in each case) can be seen in the second heating run, so the material also solidifies completely or at least essentially amorphously after melting.

Table 3: Melting temperature, specific enthalpy of fusion and particle size distribution of the powdered material according to the invention. Example V5:

The powder was produced analogously to example V1, the temperature gradient during cooling being -0.5 K/min. The material used was PEI with the trade name Ultern CRS5011 from Sabic.

Comparable to example V1, the powder obtained is distinguished by a particularly high melting point of 319.5° C. and a fusion enthalpy of 41.5 J/g, determined by means of DSC measurement (FIG. 7, first heating run, upper curve). The absence of a crystallization peak in the cooling run (lower curve, Fig. 7) and melting peaks in the second heating run (middle curve, Fig. 7) shows that the material solidifies completely or at least substantially amorphously after melting.

With an average particle size of 33.2 μm (D50) and a D10 and D90 of 15.3 μm and 37.4 μm, a fine powder with a narrow particle size distribution (distribution range of 0.67) that was well suited for laser sintering was obtained, which despite Its fineness allows it to flow very well, recognizable by the compressive strength of 845 Pa determined using the Schultze ring shear cell and the ff _c of 5.2 (see Table 4, below).

Table 4: Melting temperature, specific enthalpy of fusion, particle size distribution, compressive strength (unconfined yield strength: UYS) and flow factor (ff _c ) of a powder according to the invention.

Comparative Examples C6 and C7 (not according to the invention):

For this powder, polyetherimide (trade name Ultern CRS5011, Sabic) was crystallized in granular form in dichloromethane (treatment for 24 h in the liquid solvent), then dried in a vacuum oven at 120 °C and 150 mbar under a stream of dry nitrogen and cryogenically using a pin mill -20 °C grind. Finally, the powder was sieved off at 150 μm.

For C7, the powder obtained was additionally recrystallized using dichloromethane and then dried in accordance with the conditions for the granules (C6). The powders generated by this method are characterized by a particle size distribution that is also well suited for laser sintering with an average particle size D50 of 59.8 pm (V6) or 67.3 pm (V7), which was determined in the DSC measurement in the first heating run A recognizable melting peak (upper curve, FIG. 8 for V6 and FIG. 9 for V7) shows that the powder is partially crystalline.

The powder generated in V6 has a melting temperature of 252.9 °C and a specific enthalpy of fusion of 9.7 J/g, the powder from V7 has a melting temperature of 259.7 °C and a specific enthalpy of fusion of 29.0 J/g . The melting temperatures in particular are therefore significantly below those of a powder according to the invention.

Table 5: Melting temperature, specific enthalpy of fusion and particle size distribution of the powder according to comparative examples C6 and C7.

Claims

patent claims

1. Composition, in particular powdery material, comprising at least one polymer, wherein the polymer is in the form of polymer particles and wherein the polymer is selected from at least one thermoplastic polymer,

- wherein the at least one polymer solidifies from a melt in at least essentially amorphous or completely amorphous form and can be represented in this way,

- that a melting temperature of the polymer is at least 280 °C, preferably at least 290 °C, preferably at least 300 °C, and/or wherein a melting temperature of the polymer is up to 400 °C, preferably up to 375 °C, particularly preferably up to 350° C., and/or that a specific enthalpy of fusion of the polymer is at least 28 J/g, preferably at least 30 J/g, preferably at least 40 J/g and/or wherein a specific enthalpy of fusion of the polymer is up to up to 150 J/g, preferably up to 125 J/g, preferably up to 100 J/g.

2. Composition, in particular powdered material, comprising at least one polymer, in particular according to claim 1, wherein the polymer is in the form of polymer particles and wherein the polymer is selected from at least one thermoplastic polymer, wherein the at least one thermoplastic polymer from a melt in at least im Solidified substantially amorphous or completely amorphous form, the composition being obtainable by precipitation from a first moderate solvent or a mixture of the first and at least one further moderate solvent, and wherein the first moderate solvent and/or the further moderate solvent is selected from at least an organic moderate solvent.

3. The composition of claim 1 or 2, wherein the thermoplastic polymer is selected from at least one polyetherimide, polycarbonate, polyarylethersulfone, polyphenylene oxide, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-styrene-acrylate copolymer, polyvinyl chloride, polyacrylate, polyester, polyamide, Polyaryl ether ketone, polyether, polyurethane, polyimide, polyamideimide, polyolefin, polyarylene sulfide, polysiloxane and their copolymers and/or at least one polymer blend based on the aforementioned polymers and/or copolymers.

4. Composition according to any one of the preceding claims, wherein the thermoplastic polymer comprises at least one partially crystalline polymer and/or at least one partially crystalline copolymer and/or at least one partially crystalline polymer blend.

5. Composition according to any one of the preceding claims, wherein the thermoplastic polymer comprises at least one polyetherimide, and wherein the polyetherimide repeating units according to and / or repeating units according to and / or repeating units according to

Formula III has, preferably the polyetherimide has repeating units according to the

Formula III.

6. The composition according to any one of the preceding claims 1 to 5, wherein the moderate solvent is selected from at least one cyclic solvent such as from the group of lactams, phenones, phenols, cycloalkanes and/or cycloalkanones, preferably from a homocyclic solvent such as benzene, Cyclohexanone, acetophenone and/or phthalic acid ester and/or a heterocyclic solvent such as thiophene and/or cyclic ether, particularly preferably from an aromatic homocyclic solvent such as acetophenone, dimethyl phthalate and/or benzene, especially from an aromatic, non-halogenated homocyclic solvent.

7. Composition according to one of the preceding claims 1 to 6, wherein a solubility parameter of the agent or solvent is at least 10 MPa ^1/2 lower, preferably at least 8 MPa ^1/2 lower, preferably at least 5 MPa ^1/2 lower and/or at most 10 MPa ^1/2 higher, preferably at most 8 MPa ^1/2 higher, preferably at most 5 MPa ^1/2 higher than a solubility parameter of the at least one polymer.

8. Composition according to any one of the preceding claims 1 to 7, wherein the at least one agent or solvent is selected from dimethyl phthalate and/or acetophenone.

9. A method for producing a composition, in particular a powdered material, according to any one of claims 1 to 8, wherein the method comprises at least the following steps:

(ii) Bringing together, in particular mixing, the polymeric material with an agent, preferably a solvent, preferably at a first temperature, the agent not dissolving the at least one polymer at the first temperature and the agent at a second temperature which is higher than the first temperature that at least partially dissolves a polymer,

(iii) heating the polymer-solvent mixture thus obtained, preferably with stirring, at least up to the second temperature in order to dissolve the polymer in the solvent,

(iv) cooling the polymer-solvent mixture, preferably at least to a third temperature, preferably with stirring, to precipitate the polymer from the solvent, and

(v) obtaining the powdered material.

10. A method for producing a composition according to claim 9, in particular a powdered material according to any one of claims 1 to 8, wherein the method additionally comprises at least one of the following steps:

(b) Addition of at least one first excipient or anti-agglomeration agent to the composition or to the pulverulent material, the addition taking place in particular after step v) mentioned above.

11. A process for producing a composition according to claim 9 or 10, wherein the polymer-solvent mixture contains at least 1% by weight of at least one thermoplastic polymer, preferably at least 5% by weight, preferably at least 10% by weight and/or at most 50 % by weight, preferably at most 40% by weight, preferably at most 30% by weight, in particular at most 25% by weight.

12. A method for producing a composition according to claim 9 to 11, wherein a moderate solvent is used, which is selected from at least one non-halogenated, aromatic moderate solvent, wherein preferably a solubility parameter of the moderate solvent is at least 10 MPa ^1/2 lower, preferably at least 8 MPa ^1/2 lower, preferably at least 5 MPa ^1/2 lower and/or at most 10 MPa ^1/2 higher, preferably at most 8 MPa ^1/2 higher, preferably at most 5 MPa ^1/2 higher than a solubility parameter of the at least one Polymer, and/or wherein the moderate solvent is selected in particular from at least dimethyl phthalate and/or acetophenone, wherein the at least one polymer is preferably selected from at least one polyimide and/or a polyarylethersulfone, preferably from at least one polyetherimide.

13. A method for producing a composition according to any one of claims 9 to 12, wherein the cooling of the polymer-solvent mixture, in particular from a second temperature to a third temperature, takes place in such a way that a cooling rate of the polymer-solvent mixture with a cooling rate of at least 0, 05 °C/min, preferably at least 0.1 °C/min, particularly preferably at least 0.5 °C/min, in particular at least 1° C./min, particularly preferably at least 1.5° C./min and/or at most 4° C./min, preferably at most 3° C./min, in particular at most 2° C./min .

14. A method for producing a component, in particular a three-dimensional object, comprising the steps:

(i) Application of a layer of a composition, in particular a powdered material, according to any one of claims 1 to 8 and / or a composition or a powdered material produced by a method according to claims 9 to 13 on a construction site, wherein the composition at least one polymer includes,

(ii) selective solidification of the applied layer of powdered material at locations corresponding to a cross section of the object to be manufactured, preferably by means of an irradiation unit, and

15. Composition, in particular pulverulent material, according to any one of claims 1 to 8, wherein the composition is obtainable by a method according to claims 9 to 13.

16. Component, in particular three-dimensional object, comprising a composition according to any one of claims 1 to 8, wherein the component is preferably obtainable by a method according to claim 14.

17. Component, in particular three-dimensional object, comprising a composition according to any one of claims 1 to 8, wherein the component is preferably produced by a method according to claim 14, wherein the component is in amorphous or at least substantially amorphous form.

18. Use of a composition, in particular a powdered material according to any one of claims 1 to 8, which was produced in particular by a method according to any one of claims 9 to 13, for additive manufacturing methods, preferably from the group of powder-based manufacturing methods, particularly preferably the powder bed based additive manufacturing processes, including laser sintering, High-speed sintering, binder jetting, MultiJetFusion, selective mask sintering, selective laser melting, LaserProFusion, in particular for use in a method according to claim 14.