Powder coatings: II

Powder coating is undergoing rapid growth. Worldwide production of powder c oatings in 1996 was estimated to be about 450,000 metric tons.(1) Powder co atings are used most extensively in Europe and Japan; North American produc tion in 1996 was estimated to be 110,000 metric tons. The general principle is to formulate a coating from solid components, melt mix them, disperse p igments (and other insoluble components) in a matrix of the major binder co mponents, and pulverize the formulation. The powder is applied to the subst rate, usually metal, and fused to a continuous film by baking. Thermosettin g and thermoplastic powders are available; the major portion of the market (>90%) is for thermosetting types.