International Coatings Limited

Gareth Dale Crapper

Kevin Jeffrey Kittle

John Ring

Martyn P Care

Powder coating compositions incorporate, by dry blending, a wax-coated silica additive in finely divided form. Further additives that may be incorporated by dry blending include aluminum oxide and/or aluminum hydroxide. The compositions offer advantages, for example, in terms of fluidity and in terms of first-time deposition of fine particles.

Powder coating compositions

A powder coating composition comprises a mixture of first and second component powder coating compositions which are separate, preferably widely separated, in a triboelectric reference series indicative of the extent to which powder coating compositions may be distinguishable from one another when electrically charged. The mixed powder coating composition is especially suitable for coating articles having recessed portions. A quantitative basis is given for determining the separation of the individual component compositions in the triboelectric reference series, and preferred minimum separation criteria are given.

Powder coating composition having a mixture of first and second component powder coating compositions.

A powder coating composition of the invention comprises a film-forming polymeric component having a d(v, ) in the range or from 25 to 50 microns or a d(v, ) in the range of from 25 to 70 microns, which composition incorporates by dry-blending at least one appearance-modifying additive component and a further component comprising wax-coated silica or consisting of alumina together with aluminum hydroxide. The appearance-modifying additive may be a gloss-reducing component, a texturing component, a metallic or mica component, a coloring pigment, or a further film-forming polymeric material comparable with the first film-forming polymeric material and differing in coloration therefrom, and the further additive may be alumina together with aluminum hydroxide, wax-coated silica, or a combination thereof. Preferably, no more than 70% by volume of the particles in the film-forming polymeric material are less than 50 microns. A kit of the invention comprises the individual additive components prior to mixing. The kit allows for the flexible production of a variety of finishes from a gloss powder coating composition, for example, a matte, textured, metallic, or sparkle finish, a matte metallic finish, an antique finish, or a contrast texture or metallic sparkle finish.

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Tyne and Wear, United Kingdom

Gareth Dale Crapper