COATING PROCESSES

摘要

It is known in curtain coating to use a bottom or accelerating layer to promote wetting of a moving support on to which a liquid material comprising one or more layers is being deposited. Although high coating speeds can be obtained, it is difficult to deliver a low viscosity and relatively low flow rate layer as a bottom layer down the inclined slide of a hopper, without waves and other manifestations of unstable flow. Described herein is an improved process for curtain coating in which a thin, low viscosity bottom layer is used allowing high viscosity liquids to be deposited simultaneously on to a moving support without the problems associated with known curtain coating processes.