Effect of Coating Viscosity on Surface Latex Concentration, 1991 Coating Conference Proceedings

The objective of this work was to evaluate the influence of coating viscosity on the migration of latex binder during drying. Clay/latex coatings were applied to paper basestock with a Keegan coater. Latex migration was induced with hot air impingement. Surface latex concentration was measured using an ultraviolet absorbance technique.

Bentonite, glycerol, polyvinyl alcohol (PVA), carboxymethylcellulose (CMC), and sodium alginate were used to increase coating viscosity. Viscosity increases due to bentonite or glycerol had no impact on the latex concentration at the surface of the dried coating. However, viscosity increases due to the addition of the polymers PVA, CMC, and sodium alginate resulted in a significant reduction in the surface latex concentration. The order of their effectiveness at reducing surface latex concentration was alginate > CMC > PVA.

Apparently, polymer addition to the paper coatings inhibited latex migration, but higher coating viscosities did not.