Recycling Paint Overspray

By Hiren Sanghvi, John L. Massingill, Jr.

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.