Polyamide fluidized-bed-coating powder for thin-layer fluidized-bed coating
AssigneeDegussa AG
InventorsDirk Heinrich, Heinz Scholten
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Abstract
One embodiment of the present invention provides a polyamide powder, which includes polyamide particles having a median grain size d 50 of from 20 to 90 μm, a content of fines <5 μm of below 1% by weight, and at least 75% by weight of spherical particles in which all three spatial axes x, y and z of the individual particles have the same dimension to within ±10%. Other embodiments of the invention provide a process for making and using the powder, and articles coated articles obtained thereby.
Claims18
1-9. (canceled)
A process for obtaining a polyamide powder, comprising:
- screening a polyamide powder to remove particles having a size of ≧125 μm to obtain a screened powder;
- mechanically post-treating the screened powder to round off corners and edges, to obtain a post-treated powder;
- and
- removing a portion of fines having a size of <5 μm from the post-treated powder, to obtain a polyamide powder product, comprising
- polyamide particles having a median grain size d 50 of from 20 to 90 μm,
- a content of fines <5 μm of below 1% by weight, and
- at least 75% by weight of spherical particles in which all three spatial axes x, v and z of the individual particles have the same dimension to within ±10%.
A coated surface, prepared by a process comprising, in a fluidized-bed coating process, fluidizing said polyamide powder product, contacting the fluidized powder with a metal surface, and forming a polyamide coating on said metal surface.
A process for coating a surface, comprising:
- in a fluidized-bed coating process, fluidizing a polyamide powder to obtain a fluidized polyamide powder;
- contacting the fluidized powder with a metal surface and
- forming a polyamide coating on said metal surface;
- wherein said coating has a thickness of 50 to 200 μm,
- wherein said polyamide powder comprises
- polyamide particles having a median grain size d 50 of from 20 to 90 μm,
- a content of fines <5 μm of below 1% by weight, and
- at least 75% by weight of spherical particles in which all three spatial axes x, y and z of the individual particles have the same dimension to within ±10%.
(canceled)
Dependencies are inferred from the claim text.