VACUUM WEB COATING

摘要

VACUUM WEB COATING In an apparatus for vacuum web coating, an evaporation means has a plurality of separately spaced outlet nozzles through which vapour is conveyed to a deposition zone at the surface of a chilled rotatable drum in a vacuum chamber over which drum the substrate web is advanced by a web transport system. The outlet nozzle arrangement advantageously comprises a plurality of linear slots disposed transversely to the web substrate path to deliver vapour at positions disposed sequentially in the direction of the web substrate advance, the nozzle outlets being disposed on an arcuate surface around, but spaced from, the curved surface of the rotatable drum. By varying the nozzle profile, for example the width and/or spacing of the nozzle outlets the application of the coating may be tightly controlled to obtain improved uniformity of the coating, material collection efficiency and control of the substrate heat loading. The apparatus is particularly suitable for applying thick coatings of material such as metal on paper or plastic films.