摘要：
The invention is in the field of additive manufacturing. There is provided a method for manufacturing a powder composition having a D50 particle size value of 20-150 microns suitable for powder bed fusion additive manufacturing processes, comprising the steps of: (a) providing a particulate starting material comprising a semicrystalline polymer; (b) optionally, compacting the starting material with a compacting pressure of >5 kN/cm2, thereby obtaining a compacted material; (c) optionally, reducing the size of the particulate starting material or the compacted material; (d) dry blending the starting material, the compacted material, or the size-reduced material with a pigment using high shear mixing; (e) optionally, size fractionating the starting material, the compacted material, the size-reduced material and/or the dry blended material. There is also provided a powder composition having a D50 particle size value of 20-150 microns, preferably obtainable by a such a method, suitable for additive manufacturing powder bed fusion processes, comprising a semicrystalline polymer and a pigment, wherein the powder composition has a reflectance at 800 nm of 50 % or less, preferably 25 % or less. There is also provided an additive manufacturing method for producing a three-dimensional article, comprising the step of subjecting such a powder composition to powder bed fusion, as well as an article comprising a semicrystalline polymer, obtainable by a such a method.
技术功效语段：
[0025]The inventors have found that powder compositions that are made using a method that involves mixing a starting material comprising a semicrystalline polymer with a pigment using a high shear mixing can be used to produce articles with improved toughness using additive manufacturing. In addition, in powder compositions prepared using the method according to the first aspect of the invention, less pigment is needed in order to absorb the same amount of electromagnetic radiation in the near-infrared compared to powder compositions prepared using other methods.
权利要求：
1. Method for manufacturing a powder composition having a D50 particle size value of 20-150 microns suitable for powder bed fusion additive manufacturing processes, comprising the steps of: (a) providing a particulate starting material comprising a semicrystalline polymer; (b) optionally, compacting the starting material with a compacting pressure of >5 kN/cm2, thereby obtaining a compacted material; (c) optionally, reducing the size of the particulate starting material or the compacted material; (d) dry blending the starting material, the compacted material, or the size-reduced material with a pigment using high shear mixing; (e) optionally, size fractionating the starting material, the compacted material, the size-reduced material and/or the dry blended material.
2. Method according to claim 1, wherein the semicrystalline polymer is selected from the group consisting of polyesters, polyolefins, polyamides, and combinations thereof.
3. Method according to claim 1 or 2, wherein the semicrystalline polymer is a homopolymer or copolymer of 3-hydroxy butyric acid, and wherein preferably a test article obtained by powder bed fusion of the resulting powder composition has an elongation-at-break of more than 4 %, measured according to ISO 527.
4. Method according to claim 3, wherein the semicrystalline polymer is a copolymer of 3-hydroxy butyric acid and a comonomer selected from 3-hydroxy hexanoic acid and 3-hydroxy valeric acid.
5. Method according to claim 1 or 2, wherein the semicrystalline polymer is polybutylene terephthalate or a copolymer thereof.
6. Method according to any one of claims 1-5, wherein the amount of the semicrystalline polymer relative to the total weight of the resulting powder composition is 80-99.9 %.
7. Method according to any one of claims 1-6, wherein the amount of pigment relative to the total weight of the resulting powder composition is 2.0 % or less, preferably 1.0 % or less.
8. Method according to any one of claims 1-7, wherein the pigment has a reflectivity at 800 nm of 20 % or less, and is preferably selected from the group consisting of carbon black, carbon black, ultramarine blue, iron oxides, organic pigments, and combinations thereof.
9. Method according to any one of claims 1-8, further comprising the step of heating the starting material, the compacted material, and/or the size reduced material to a temperature sufficient to prevent sticking of the starting material or compacted material, thereby obtaining an annealed material.
10. Powder composition having a D50 particle size value of 20-150 microns, preferably obtainable by a method according to any one of claims 1-8, suitable for additive manufacturing powder bed fusion processes, comprising a semicrystalline polymer and a pigment, wherein the powder composition has a reflectance at 800 nm of 50 % or less, preferably 25 % or less.
11. Powder composition according to claim 10, wherein the semicrystalline polymer is a homopolymer or copolymer of 3-hydroxy butyric acid, and wherein preferably a test article obtained by powder bed fusion of the powder composition has an elongation-at-break of more than 4 %, measured according to ISO 527.
12. Powder composition according to claim 10, wherein the semicrystalline polymer is polybutylene terephthalate.
13. Additive manufacturing method for producing a three-dimensional article, comprising the step of subjecting a powder composition according to any one of claims 10-12 to powder bed fusion.
14. Article comprising a semicrystalline polymer, obtainable by a method according to claim 13.
15. Article according to claim 14, wherein the semicrystalline polymer is a homopolymer or copolymer of 3-hydroxy butyric acid, wherein the article has an elongation-at-break of more than 4 %, measured according to ISO 527.