Polymer powder for powder bed fusion methods
A polymer powder having a surface energy of less than 35 mN/m is suitable for melting/sintering powder particles for layer-by-layer production of three-dimensional objects.
1. A method for producing a polymer powder having a surface energy of less than 35 mN/m, said method comprising:
coating a polymer powder with a hydrophobic substance, thereby obtaining the polymer powder having a surface energy of less than 35 mN/m.
2. The method according to claim 1 , wherein the coating is effected at a temperature of not more than 100° C.
3. The method according to claim 1 , wherein the coating is effected in a suspension.
4. The method according to claim 1 , wherein said hydrophobic substance is selected from the group consisting of alkanes, alkenes and mixtures thereof.
5. The method according to claim 1 , wherein the polymer of the polymer powder is at least one member selected from the group consisting of a polyamide and a copolyamide.
6. The method according to claim 1 , wherein the polymer powder has a Wadell sphericity is at least 0.5.
7. The method according to claim 1 , wherein the polymer powder has a surface energy of less than 32 mN/m.
8. The method according to claim 1 , wherein the polymer powder has a surface energy of less than 30 mN/m.
9. The method according to claim 1 , wherein a proportion of the hydrophobic substance accounts for 0.15% to 20% by weight, based on the total weight of polymer powder and the hydrophobic substance.
10. The method according to claim 1 , wherein the hydrophobic substance has a melting point of not more than 160° C. and a boiling point of at least 190° C.
11. A powder bed fusion method, comprising:
selectively laser sintering, selectively absorbing sintering, or selectively inhibition sintering a polymer powder having a surface energy of less than 35 mN/m.
12. A shaped body obtainable by the method according to claim 11 .
13. The method according to claim 11 , wherein the polymer of the polymer powder is at least one member selected from the group consisting of a polyamide and a copolyamide.
14. The method according to claim 11 , wherein the polymer powder has a Wadell sphericity is at least 0.5.
15. The method according to claim 11 , wherein the polymer powder has a surface energy of less than 32 mN/m.
16. The method according to claim 11 , wherein the polymer powder has a surface energy of less than 30 mN/m.
17. The method according to claim 11 , wherein
said polymer powder comprises a hydrophobic substance on a surface thereof, and
a proportion of the hydrophobic substance accounts for 0.15% to 20% by weight, based on the total weight of polymer powder and the hydrophobic substance.
18. The method according to claim 11 , wherein
said polymer powder comprises a hydrophobic substance on a surface thereof, and
the hydrophobic substance has a melting point of not more than 160° C. and a boiling point of at least 190° C.
19. The method according to claim 11 , wherein
said polymer powder comprises a hydrophobic substance on a surface thereof, and
said hydrophobic substance is selected from the group consisting of alkanes, alkenes, and mixtures thereof.
20. The method according to claim 11 , wherein surface energy is determined by a contact angle method.