Optimizing the Coating Formulation to Reduce Misting in High-Speed Film Coating, 1996 Metered Size Press Forum Proceedings

Pekka Salminen, Robert Urscheler, Dan Chase, John Roper III - Dow Chemical

Control of misting and orange peel formation are critical issues for high-speed film coaters. This paper reports on a series of pilot coater trials aimed at identifying some of the key coating parameters influencing misting and optimizing the coating formulation to reduce misting. Earlier work by others has suggested that dewatering and the thickness of the non-immobilized layer have a strong influence on misting and orange peel formation. Independently, we have investigated the role of coating immobilization as well as coating rheology on the film splitting process. It appears that the high shear viscosity of a coating plays a significant role in controlling misting. This information was used to optimize high-speed film coating using high coating solids combined with latex technology which allows the reduction or elimination of thickener in the coating formulation.