Abstract: An apparatus and method for evaporating a coating solvent from a coating on a substrate and for minimizing the formation of mottle. The coating is heated with a first drying gas at no higher than a first heat transfer rate. The first heat transfer rate is created by a first heat transfer coefficient and a first temperature difference between the first coating temperature and the first drying gas temperature. The first heat transfer rate causes maximum evaporation of the coating solvent yet insignificant formation of mottle when the coating is at the first coating thickness and the first coating viscosity.

Abstract: An apparatus and method for evaporating a coating solvent from a coating on a first substrate surface of a substrate and for minimizing the formation of mottle as the coating solvent is evaporating. A drying oven includes an enclosure having an inlet and an outlet and defining a first drying zone. A plurality of drying subzones are within the first drying zone. At least two of the plurality of drying subzones employ different and controllable drying conditions. Physical barriers are not required to create the plurality of drying subzones.

Abstract: An apparatus and method for evaporating a coating solvent from a coating on a first substrate and for minimizing the formation of mottle. A drying oven includes a plurality of air foils positioned adjacent to the second substrate surface. Each of the plurality of air foils have a foil slot through which a stream of drying gas is supplied to the drying oven. The foil slot length is adjusted to not be significantly greater than the first substrate width to minimize air flow over the first and second coating edges which minimizes the creation of mottle.