Recycling paint overspray

The use of recovered paint overspray from the auto industry was investigated. Water and solvent had been removed from the recovered paint by a vacuum treatment process. The acid catalyst had been neutralized by excess base prior to processing. The recovered paint, as supplied, contained contaminant particles of self-crosslinked hardener that were removed by filtration. The cleaned paint was then formulated with additional catalyst and additional crosslinker to replace that which was lost in processing, and solvent (55% solids, 3 lb/gal VOC) to reach application viscosity. The paint was applied to metal test panels and baked at 190°C for 15, 20, or 25 min. The results indicate that the gray recycled paint gave reasonable properties for many expected industrial applications. Center for Coatings and Bio-Based Technology, Institute for Environmental and Industrial Science, San Marcos, Texas 78666