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EP-4735234-A1 - METHOD FOR MANUFACTURING A THREE-DIMENSIONAL OBJECT

EP4735234A1EP 4735234 A1EP4735234 A1EP 4735234A1EP-4735234-A1

Abstract

The invention relates to a method for manufacturing a three-dimensional object using additive manufacturing, in particular selective laser sintering (L-PBF), said method comprising the steps of: (a) providing a starting material that is solid at 25°C and comprises a thermally curable resin composition and a sintering material, (b) additively manufacturing the three-dimensional object, (c) thermally curing at least part of the resin composition in the three-dimensional object, (d) decomposing the resin composition in the three-dimensional object, and (e) thermally treating the three-dimensional object. The invention also relates to the use of a starting material that is solid at 25°C in additive manufacturing, in particular in selective laser sintering (L-PBF), to manufacture a three-dimensional object, wherein the starting material comprises a thermally curable resin composition and a sintering material, characterised in that the starting material comprises the sintering material in an amount of 20 vol.% or more relative to the total volume of the starting material.

Inventors

  • SEIRINGER, Sarah
  • SCHIMO-AICHHORN, Gabriela
  • SCHEITHAUER, UWE
  • BERGER, CHRISTIAN

Assignees

  • TIGER Coatings GmbH & Co. KG
  • Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.

Dates

Publication Date
20260506
Application Date
20240628

Claims (20)

  1. 1. A method for producing a three-dimensional object using additive manufacturing, in particular selective laser sintering (L-PBF), comprising the steps: (a) providing a starting material which is solid at 25 °C and comprises a thermosetting resin composition and a sintered material, (b) Additive manufacturing of the three-dimensional object, (c) at least partially heat curing the resin composition in the three-dimensional object, (d) decomposition of the resin composition in the three-dimensional object, and (e) Heat treatment of the three-dimensional object.
  2. 2. The method according to claim 1, characterized in that the additive manufacturing of the three-dimensional object in step (b) is carried out with at least partial heat curing of the resin composition.
  3. 3. Process according to claim 1 or 2, characterized in that the at least partial heat curing of the resin composition in step (c) is carried out with a gradual increase in temperature.
  4. 4. Method according to one of claims 1 to 3, characterized in that the sintered material is a ceramic precursor.
  5. 5. The method according to claim 4, characterized in that the sintered material is selected from the group comprising titanium dioxide, zirconium oxide, silicon carbide, aluminum hydroxide and aluminum oxide, or a mixture thereof.
  6. 6. The method according to claim 5, characterized in that the sintered material is selected from the group comprising titanium dioxide, aluminum hydroxide and aluminum oxide, or a mixture thereof.
  7. 7. Process according to one of claims 1 to 6, characterized in that the starting material comprises a black pigment.
  8. 8. Process according to one of claims 1 to 7, characterized in that the thermosetting resin composition comprises an epoxy resin and a hardener for the epoxy resin, wherein the hardener preferably contains at least one amine group and/or at least one amide group.
  9. 9. Process according to one of claims 1 to 8, characterized in that the resin composition comprises at least two thermosetting resins and a hardener.
  10. 10. Method according to one of claims 1 to 9, characterized in that the Resin composition comprises at least two thermosetting resins and at least two hardeners.
  11. 11. Method according to one of claims 1 to 10, characterized in that the Starting material comprises the sintered material in an amount of 20 vol% or more, based on the total volume of the starting material.
  12. 12. The method according to claim 11, characterized in that the starting material comprises the sintered material in an amount of 25 vol% or more, preferably 30 vol% or more, more preferably 35 vol% or more, particularly preferably 40 vol% or more; preferably in the range from 25 to 65 vol%, more preferably in the range from 30 to 60 vol%, even more preferably in the range from 35 to 60 vol%, even more preferably in the range from 40 to 60 vol%, particularly preferably from 40 to 55 vol%, based on the total volume of the starting material.
  13. 13. Method according to one of claims 1 to 12, characterized in that the thermosetting resin composition at least partially envelops the sintered material.
  14. 14. Process according to one of claims 1 to 13, characterized in that the thermosetting resin composition comprises a hardener, wherein the hardener is preferably selected from the group comprising a hardener containing a functional group, an initiator and a catalyst, or a mixture thereof.
  15. 15. Process according to one of claims 8 to 14, characterized in that the at least two thermosetting resins comprise at least one epoxy resin and at least one carboxylated polyester resin, and that at least one hardener preferably contains at least one amine group and/or at least one amide group.
  16. 16. Use of a starting material which is solid at 25 °C in additive manufacturing, in particular in selective laser sintering (L-PBF), for producing a three-dimensional object, wherein the starting material comprises a thermosetting resin composition and a sintered material, characterized in that the starting material comprises the sintered material in an amount of 20 vol% or more, based on the total volume of the starting material.
  17. 17. Use according to claim 16, characterized in that the starting material comprises the sintered material in an amount of 25 vol% or more, preferably 30 vol% or more, more preferably 35 vol% or more, particularly preferably 40 vol% or more, based on the total volume of the starting material.
  18. 18. Use according to claim 16 or 17, characterized in that the sintered material is selected from the group comprising titanium dioxide, zirconium oxide, silicon carbide, aluminum oxide, aluminum hydroxide and mixtures thereof.
  19. 19. Use according to one of claims 16 to 18, characterized in that the resin composition comprises at least two thermosetting resins and at least one hardener.
  20. 20. Use according to one of claims 16 to 19, characterized in that the starting material comprises a black pigment.

Description

Method for producing a three-dimensional object The present invention relates to a method for producing a three-dimensional object using additive manufacturing, in particular selective laser sintering (L-PBF). The invention further relates to the use of a starting material that is solid at 25 °C in additive manufacturing, in particular in selective laser sintering (L-PBF), for producing a three-dimensional object, wherein the starting material comprises a thermosetting resin composition and a sintered material. Methods for producing three-dimensional objects by means of additive manufacturing are known in the prior art. A method for producing three-dimensional plastic objects is described, for example, in DE 10 2019 212 298 A1, wherein a powder mixture is used for selective laser sintering. The powder mixture comprises a first powder with powder particles containing a first thermoplastic polymer material and a reinforcing material, and a second powder with powder particles containing a second thermoplastic polymer material. The reinforcing material can comprise carbon fibers, glass fibers, carbon nanotubes, glass spheres or a flame retardant, wherein the flame retardant can comprise metal oxides, metal hydroxides, metal II salts, boron and zinc compounds, silicon compounds, graphite or nitrogen-based melamine-based flame retardants. Methods for producing three-dimensional ceramic objects are also known in the prior art, for example from WO 2018/005350 Al, where production takes place using a fused filament fabrication (FFF) process. A mixture that is flowable at room temperature and consists of an organic reactive material (e.g. prepolymers of polyurethanes, polyesters, epoxies, silicones) and inorganic particles is used. The inorganic particles can comprise a metal or a ceramic, such as an oxide, nitride or carbide. The amount of inorganic particles in the mixture can be in the range of 10 to 80% by weight, based on the total weight of the mixture. The mixture is laid in layers in the form of filaments at room temperature or extruded directly to produce a three-dimensional object. The organic reactive material is then cured at room temperature or an elevated temperature to obtain a duromer. The three-dimensional object is then heated to a temperature of 400 °C or more to decompose the thermoset, forming a carbon phase to bind the inorganic particles. The resulting three-dimensional object has a high porosity of at least 35%. Furthermore, photolithographic processes are also used to produce three-dimensional ceramic objects, for example Lithography-based Ceramic Manufacturing (LCM) processes. In this process, a liquid mixture comprising a photopolymer and a ceramic raw material is printed layer by layer. After each layer has been applied, the photopolymer contained therein is polymerized by irradiation with light. After additive manufacturing, the three-dimensional object is heated to remove the binder and the ceramic particles are subsequently compacted by sintering. Ceramic objects with a comparatively high resolution can be produced using the LCM process. However, care must be taken to ensure that the light is not scattered or absorbed by the ceramic raw material, as this can impair printability and resolution. LCM processes also have low productivity and are costly. Another established method for producing three-dimensional objects is binder jetting (BJT). In this method, powdered starting material is applied layer by layer and selectively bonded with an organic binder between each application process. The resulting objects in the form of bonded powders have a high porosity of usually over 50 vol% and only a low compressive strength. Furthermore, methods for producing three-dimensional ceramic or metallic objects by means of additive manufacturing are known in the state of the art. EP 2998 282 Al relates to a method for producing a reaction-bonded silicon carbide component. WO 2018/079169 Al relates to a method for producing modelling material, modelling material, three-dimensional modelling method and three-dimensional modelling system. US 2005/0191200 Al relates to a method and a composition for the production of metal freeform surfaces. WO 2016/127521 Al relates to a method for producing a composite product from short fiber-reinforced thermosetting resin by means of 3D printing. The quality of three-dimensional ceramic objects produced by additive manufacturing can hardly be improved by post-processing (e.g. grinding), since this is complex and difficult due to the hardness and brittleness of the ceramic object, and is associated with high tool wear and a risk of breakage of the ceramic object. Also, some surfaces of geometrically complex objects often cannot be post-processed at all due to their inaccessibility, or can only be done by complex flow grinding. There is therefore a need for a method with which three-dimensional, particularly ceramic, objects can be produced with fine, complex structure