Thermosetting powder coating are much more widely used
Thermosetting powder coating are applied by the electrostatic spray process, heated to the necessary temperatureand cured and are primarily composed of relatively high molecular weightsolid resins and a crosslinker.The formulation of thermosetting powders contain the primary resins:Epoxy,Polyester,Acrylic.
These primary resins are used with different crosslinkers to produce a variety of powder materials. Many crosslinkers, or cure agents, are used in powder coatings, including amines, anhydrides, melamines, and blocked or non-blocked isocyanates.Some materials also use more than one resin in hybrid formulas.
When a thermoset powder is applied and subjected to heat it will melt, flow and chemically crosslink to form a finished film.The chemical reaction in the cure cycle creates a polymer network that provides excellent resistance to coating breakdown. A thermoset powder that has cured and crosslinked will not melt and flow again if subjected to heat a second time.