New Additive Chemistry for Improved Pigment Suspension Control
This paper provides insight into THIXATROL® UV1104, a new polyester-based, rheology-modifying additive chemistry, to help eliminate some common rheological problems and optimize pigmented UV coatings. Coatings formulators will get a full picture regarding a new developmental composition, its base chemistry and incorporation procedures to enhance coating properties and performance.
When the end user or applicator opens the container, the last thing they would like to experience is the pigment hard settled at the bottom, which brings the product's storage stability into account. From a product stability standpoint, the issue of pigment settling is not simply a matter of aesthetics. Performance too is an issue. When pigments hard settle they tend to pack to the point where they become dry (Figure 1). The dispersants and solvating fluids that initially dispersed the pigments into suspension have been forced off of the pigment particles. One symptom of this phenomenon is a loss of the fineness of grind after attempting to reincorporate the settled cake. In most cases the pigments cannot be re-incorporated back into suspension. These dry particles are applied with the coating onto the substrate. They will tend to form surface defects and inhibit the coating from forming a uniform film. Premature coating failure is likely, along with poor appearance.