The Effects of Color Concentrates on the Rheology of Tint Bases

By Douglas J. Herrick, Jason W. Boke, Maung Y. Htet, Raymond H. Fernando

Rheological properties of coatings formulated with associative thickeners are quite sensitive to a number of formulation variables. Small changes in these variables, which include the latex, thickener, and surfactant components of the coating, can have a profound effect. Many previous studies have focused on understanding and controlling these sensitivities.

However, few studies have focused on the relatively large viscosity drop and related problems when predispersed colorants are added to tint bases formulated with associative thickeners. In this study, pastel and deep-tone tint bases were formulated with associative and nonassociative thickeners. The tint bases were then tinted with six different conventional colorant dispersions and six low-VOC counterparts of the same colorants.

Effects of the colorants, thickeners, and VOCs on viscosity profiles, dynamic viscoelastic properties, color development, and gloss were determined and results are presented.