Design of pigment dispersants for high-solids paint systems

The development of pigment dispersants, either for waterborne or for high-solids paints, requires three things: the selection of an anchoring group, the selection of a soluble tail and the choice of a suitable architecture, which connects anchoring groups to soluble tails. For the selection of an anchoring group, we measured the adsorption of model compounds to pigments. This gives us the free energy of adsorption, which is a measure for the affinity of the anchoring for a given pigment. It allows a simple and relatively rapid prescreening of anchoring groups without the necessity of preparing polymers and testing them in paint formulations. Suitable soluble groups must have good compatibility with the binder and solvent of the paint system. Mapping the area of solubility as a function of solubility parameters is a simple but powerful tool to judge the suitability of pigment dispersants soluble tails for a paint system. More quantitative information is obtained from the intrinsic viscosity of the soluble tail polymers. Good results have been obtained with soluble tails with an intrinsic viscosity of about 10 ml/g. (C) 2001 Elsevier Science B.V. All rights reserved.