Devi N. Rai

Capture of overspray powder paint in a wet booth system

A chemical treatment is developed to enable capture of powder paint in a wet booth system. The treatment paves the way for use of conventional wet booth systems in small or short-term powder paint applications where capital investment for dry powder booths is unfavorable. It is found that the powder paint collection in a wet booth is possible only in the presence of a suitable wetting agent in the boothwater. The selected wetting agent is polyoxyethylene-polyoxypropylene glycol, which is a low-foaming, nonionic, surface active agent, and found to have little interference with the detackifying and flocculating functions of a melamine-based chemical treatment program.

Measurement of condensate- and smoke-causing emissions from automotive paints and sealers

Two major problems that periodically arise during the surface coating of automobiles are oven plume opacity (smoke that violates local opacity ordinances) and oven condensate that can drip on cars and leave an oily residue. Both of these problems are caused by the evaporation of semi-volatile organic compounds in bake ovens. A new test procedure has been developed to standardize the analysis and reporting of condensate/smoke-causing compounds that are emitted from paint, sealer, and coating materials when they are baked. Use of this test will allow identification and quantification of potential sources of condensate, smoke, and opacity in the laboratory. The information is essential to material suppliers and formulators, and to users who prescreen materials in order to avoid costly problems in production.