Apparatus and method for drying a coating on a substrate

Abstract

A method and apparatus for coating and drying coated substrates without introducing significant surface imperfections while running at higher web speeds than known drying methods. The substrate is preferably coated within the drying enclosure or the coating bead may form a closure at the entrance of the drying enclosure. The substrate is moved through a first drying enclosure along a first axis. The first drying enclosure is substantially isolated from an external environment. A first low velocity, substantially laminar flow field of a drying gas is directed across the front surface of the substrate. The first flow field is generally parallel to the front surface and generally perpendicular to the first axis to minimize the formation of surface imperfections during the evaporation of the coating solvent. The substrate may then be moved to subsequent drying enclosures through transition enclosures that minimize surface imperfections due to high velocity interaction between the adjacent drying enclosures. In embodiments where the first axis is in an inclined configuration with respect to horizontal, louvers may be utilized for directing solvent evolving from the substrate to minimize surface imperfections due to solvent cascade.