Electrostatic liquid spray application of coatings with supercritical fluids as diluents and spraying from an orifice
AssigneeUnion Carbide Chemicals & Plastics Technology Corporation
InventorsKenneth L. Hoy, Kenneth A. Nielsen
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Abstract
An electrostatic liquid coatings application process and apparatus is provided in which supercritical fluids, such as supercritical carbon dioxide fluid, are used to reduce to application consistency viscous coatings compositions to allow for their application as liquid sprays. The coatings compositions are sprayed by passing the composition under pressure through an orifice into the environment of the substrate. The liquid spray is electrically charged by applying a high electrical voltage relative to the substrate and electric current.
Claims16
An apparatus for electrostatic liquid spray application of a coating to a substrate wherein the use of environmentally undesirable organic solvent is diminished, said apparatus comprised of, in combination:
- (1) a source of supercritical fluid;
- (2) means for supplying at least one polymeric compound capable of forming a continuous, adherent coating;
- (3) means for supplying at least one active organic solvent;
- (4) means for supplying supercritical fluid from said source;
- (5) means for forming a liquid mixture of components supplied from the means for supplying at least one polymeric compound capable of forming a continuous, adherent coating, the means for supplying at least one active organic solvent and the means for supplying supercritical fluid from said source;
- (6) means for spraying said liquid mixture onto a substrate by passing the mixture under pressure through an orifice into the environment of the substrate to form a liquid spray containing droplets having an average diameter of 1 micron or greater;
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- (7) means for electrically charging the liquid by a high electrical voltage relative to the substrate.
Dependencies are inferred from the claim text.