Low-Yellowing Aqueous Clear Powder Coating Dispersions

August 10, 2005

l Patent No. U.S. 6,509,096 B1
BASF Coatings has obtained a patent for a process for producing single- or multi-coat clearcoat finishes on a primed or an unprimed substrate. The method entails applying at least one powder coating dispersion to the substrate to form a film, and then curing the film by at least one of thermally and with actinic radiation, wherein the powder coating dispersion comprises a binder, a crosslinking agent, oxalic acid and a polyvalent inorganic acid. The polyvalent acid is selected from the group consisting of phosphoric acid, derivatives of phosphoric acid, sulfuric acid, derivatives of sulfuric acid and boric acid. The polyvalent inorganic acid, except for phosphoric acid, is added to the powder coating dispersion in an amount from 0.1 to 2,000 ppm per entire weight of the powder coating dispersion.