SMOOTH, FLEXIBLE POWDER COATINGS

摘要

The present invention, a powder composition for making powder coatings comprising one or more than one curable polymer or resin and an agglomerate of a core-shell polymer, wherein the agglomerate of a core-shell polymer has an average particle size of from 5 to 190 microns, preferably from 10 to 127 microns. The powders in accordance with the present invention provide a cured powder coating that is flexible, smooth, and which may be applied in a thickness of only from 0.3 to 8 mils. In a preferred embodiment of making a powder in accordance with the present invention, the agglomerate is cryoground to form a reduced agglomerate prior to adding it into a powder as a post-blend or a powder-forming mixture as a preblend. The preferred core-shell polymer for use in accordance with the present invention comprises an acrylic impact modifier having a poly(methyl methacrylate) shell and a poly(butyl acrylate) core. Further, the preferred curable polymer or resin powder is an epoxy resin, wherein the powder composition is a low temperature curing one component powder composition which cures at from 107 to 149 degrees C.