Coating processes
AssigneeEastman Kodak Company
InventorsTerence D. Blake, Rosemary Dobson, Gregory N. Batts, William J. Harrison
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Abstract
In curtain coating, uniform layer or layers are only obtained if the operational variables are held within precise limits. These limits define a "coating window". However, one of the boundaries of this "window" is governed by the occurrence of air-entrainment. Described herein is an improved coating process in which allows the "coating window" to be enlarged. This is achieved by using a material adjacent the support on to which the liquid material is to be coated which readily shear-thins.
Claims9
A curtain coating process in which liquid material comprising one or more layers is coated on to a moving support, such that at least the layer of liquid material adjacent the support is a pseudoplastic liquid having viscosity greater than 20 mPas at shear rates less than 500 s.sup.-1, and a viscosity of less than 10 mPas at shear rates greater than 10.sup.6 s.sup.-1, characterized in that the viscosity of the pseudoplastic liquid approaches a substantially constant value at a shear rate which lies in a range between 10.sup.4 and 10.sup.8 s.sup.-1.
Dependencies are inferred from the claim text.