Copolyamide powder and its preparation, use of copolyamide powder in a shaping process and mouldings produced from this copolyamide powder
View Patent ↗A task often encountered in very recent times is the rapid provision of prototypes. Particularly suitable processes are those based on pulverulent materials and in which the desired structures are produced layer-by-layer through selective melting and solidification. The invention provides the constitution, production and use of a copolyamide powder which was produced using the following monomer units: a) laurolactam or ω-aminoundecanoic acid, and also b) dodecanedioic acid, and either c) decanediamine or dodecanediamine, in shaping processes, and also to moldings produced through a layer-by-layer process which selectively melts regions of a powder layer, using this specific powder. Once the regions previously melted layer-by-layer have been cooled and solidified, the molding can be removed from the powder bed. The moldless layer-by-layer processes for the production of components using the copolyamide powder result in simplified and more reliable conduct of the process and better recyclability.
1. A layer-by-layer process for production of three-dimensional components, comprising:
selective melting of regions of a powder layer of a copolyamide powder through introduction of electromagnetic energy wherein said melting occurs during said introduction of electromagnetic energy,
wherein said powder comprises monomers of:
75 to 98 parts of (a) a laurolactam or an ω-aminoundecanoic acid, and
25 to 2 parts of a copolyamide component consisting of a diacid (b) and a diamine (c), wherein said diacid (b) is a dodecanedioic acid or sebacic acid, and said diamine (c) is a decanediamine or a dodecanediamine, and
wherein said powder has a BET surface area of 5 m 2 /g or less.
2. The process according to claim 1 , wherein the powder comprises from 85 to 98 parts of (a).
3. The process according to claim 1 , wherein said copolyamide comprises said diacid and said diamine in equimolar proportions.
4. The process according to claim 1 , wherein said powder has a BET surface area of 3 m 2 /g or less.
5. The process according to claim 1 , wherein an enthalpy of fusion of the powder is more than 90 J/g.
6. The process according to claim 1 , wherein an enthalpy of fusion of the powder is more than 95 J/g.
7. The process according to claim 1 , wherein an enthalpy of fusion of the powder is more than 100 J/g.
8. The process according to claim 1 , wherein a median grain diameter of the powder D50 is from 30 to 70 μm.
9. The process according to claim 1 , wherein a median grain diameter of the powder D50 is from 32 to 60 μm.
10. The process according to claim 1 , wherein a median grain diameter of the powder D50 is from 35 to 50 μm.
11. The process according to claim 1 , wherein a solution viscosity of the copolyamide is from 1.4 to 2.3.
12. The process according to claim 1 , wherein a solution viscosity of the copolyamide is from 1.5 to 2.1.
13. The process according to claim 1 , wherein a solution viscosity of the copolyamide is from 1.55 to 1.9.
14. The process according to claim 1 , wherein a bulk density of the powder is from 300 to 600 g/l.
15. The process according to claim 1 , wherein using laurolactam, a melting point of the copolyamide powder is from 170 to 184° C.
16. The process according to claim 1 , wherein using laurolactam, a melting point of the copolyamide powder is from 175 to 184° C.
17. The process according to claim 1 , wherein using ω-aminoundecanoic acid, a melting point of the copolyamide powder is from 180 to 193° C.
18. The process according to claim 1 , wherein using ω-aminoundecanoic acid, a melting point of the copolyamide powder is from 185 to 193° C.
19. The process according to claim 1 , wherein, using laurolactam, a melting point of the copolyamide powder is from 170 to 184° C., and simultaneously a BET surface area is 3 m 2 /g or less and an enthalpy of fusion is more than 88 J/g.
20. The process according to claim 1 , wherein, using ω-aminoundecanoic acid, a melting point of the copolyamide powder is from 180 to 193° C., and simultaneously a BET surface area is 3 m 2 /g or less and an enthalpy of fusion is more than 88 J/g.
21. The process according to claim 1 , wherein the copolyamide is dissolved in a suitable solvent with exposure to heat and is then precipitated.
22. The process according to claim 1 , wherein said powder has a BET surface area of the powder ranges from 1 to 5 m 2 /g.
23. The process according to claim 1 , wherein said powder has a BET surface area of the powder ranges from 1 to 3 m 2 /g.