ABSTRACT
Solvent-based paints are applied to surfaces of parts, components, and assembled products for corrosion protection, surface protection, identification, and aesthetic appeal. Most painting is performed by conventional liquid spray technology. In spray painting, the paint is mixed with a carrier, usually an organic solvent, and is applied to the surface with an air-pressurized sprayer. Painting processes generate two significant sources of hazardous wastes: paint sludges and waste solvents. The first and largest volume of hazardous waste generated in painting involves air emissions that create paint sludges. During typical spray painting, 50% of the paint is deposited on the surface being painted; the other 50%, called overspray, is sprayed into the air. Powder coating, also called “dry powder painting,” is one of the major advances in paint application. This technique is based on depositing specially formulated thermoplastic or thermosetting, heat-fusible powders on metallic substrates. No solvents are used; therefore, the system eliminates the pollution and safety problems associated with solvent-based paints.
