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Controlling Pigment Cluster Formed Foams in Coatings Using Several Model Approaches

Richard D. Sudduth


Different approaches to control the formation of foams in coatings were addressed using several models relating to cluster sizes and cluster size distributions that resulted from combinations of existing models in the literature. Several approaches were evaluated to control Critical Pigment Volume Concentrations both experimentally and theoretically to try to control the formation of foams generated from pigment clusters in both coatings and polymer formulations. The control of pigment cluster foams was found to be most easily achieved by minimizing the Ultimate Critical Pigment Volume Concentration and optimizing the amount of dispersing agent added to the formulation. The Ultimate Critical Pigment Volume Concentration was found to be optimized by blending pigment particles with different particle shapes and different random packing fractions. Minimizing the cluster dispersion coefficient, Cq, was found to be important to keep the viscosity within controllable limits. While experimental measurements of the parameters to isolate the clustering concepts may be difficult, it is expected that better quantitative measurement of clustering concepts could eventually be very beneficial to providing improved suspension applications involving pigment cluster foams.

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