Polyamide powder with long-lasting, consistently good flowability
View Patent ↗A composition containing from 88 to 99.99% by weight of a polyamide, a compound of a polyamide and mixtures of these, and from 0.01 to 0.25% by weight of a flow aid where the drying loss from the flow aid after 5 days of conditioning at a relative humidity of 95% is less than or equal to 1%, determined by ISO 787/2.
1. A composition comprising, by weight of the composition, of from 88 to 99.99% of a polymer component selected from the group consisting of nylon-12, nylon-11, nylon-6,10, nylon 6,12, nylon-10,12, nylon-6,6, and mixtures thereof, which polymer component is the sole polymer component in the composition, and from 0.01 to 0.25% of a flow aid selected from the group consisting of a hydrophobicized silica, a hydrophobic silica, and mixtures thereof,
wherein the drying loss of the flow aid after 5 days of conditioning at relative humidity of 95% is less than or equal to 1% by weight.
2. The composition as claimed in claim 1 , wherein the polymer component has a median particle size of from 0.1 to 250 μm.
3. The composition as claimed in claim 1 , wherein the flow aid has a median particle size of from 10 nm to 150 μm.
4. The composition as claimed in claim 1 , wherein the flow aid has a specific surface area of from 20 to 600 m 2 /g.
5. The composition as claimed in claim 1 , wherein the increase in the flow time of the composition after six days of conditioning at 95% relative humidity and 40° C. followed by 24 hours of conditioning at 50% relative humidity at 20° C. is less than 20%.
6. The composition as claimed in claim 1 , wherein the flow aid is present in an amount effective for preventing caking.
7. The composition as claimed in claim 1 , wherein the flow aid is present in an amount effective for preventing an increase in the flow time of the polymer component of greater than 5% after exposure to an atmosphere of 95% relative humidity at 40° C. for 6 days followed by exposure to an atmosphere of 50% relative humidity at 20° C. for 24 hours.
8. The composition as claimed in claim 7 wherein the increase in flow time is greater than 10%.
9. A process for coating a molding, comprising
coating the molding with a composition as claimed in claim 1 .
10. The process as claimed in claim 9 , wherein the molding comprises a metal or a metal alloy.
11. The process as claimed in claim 9 , wherein the composition is fluidized during coating by injection of a gas.
12. The process as claimed in claim 9 , wherein the coating is fluidized-bed sintering, rotational sintering, electrostatic coating, tribocoating or minicoat processing.
13. A process for producing a sintered amide, comprising sintering the composition as claimed in claim 1 by laser-sintering to form the article.
14. A cosmetic comprising the composition claimed in claim 1 .
15. A coating material comprising the composition claimed in claim 1 .
16. The composition as claimed in claim 1 , wherein the polymer component is present in an amount of 95 to 99.99% by weight.
17. The composition as claimed in claim 1 , wherein the polymer component is present in an amount of 99 to 99.99% by weight.
18. The composition as claimed in claim 1 , wherein the polymer component is present in an amount of 99.8 to 99.99% by weight.
19. The composition as claimed in claim 1 , wherein the polymer component is present in an amount of 99.88 to 99.99% by weight.
20. The composition as claimed in claim 1 , wherein the polymer component is present in an amount of 99.9 to 99.99% by weight.