NEW SYNTHETIC SILICAS AS MATTING AGENTS AND THEIR EFFECT ON VISCOSITY IN WATERBORNE COATINGS

摘要

This paper describes some of the interactions of synthetic silica matting agents when they are incorporated into waterbased acrylic coatings containing associative thickeners based on Hydrophobically Modified Ethoxylated Urethane Copolymers (HEUR), Hydrophobically Modified Alkali Swellable Emulsion (HASE) and Hydrophobically Modified Ethoxylated Aminoplast (HEAT). In exclusive joint development work of BASF AG and Degussa AG, a study was conducted on the interaction of thermal silica matting agents with mentioned associative thickeners and different acrylic emulsions. These model formulations of acrylic emulsions, are characterized by several polymer compositions, emulsifiers, degrees of ethoxylation (of SLS-emulsifier) and particle sizes, Synthetic silicas can sometimes interfere with the viscosity of associative thickened binders, by dropping the viscosity to a level of the unthickened binder. The effect of mentioned coating components, like thermal silica matting agents, associative thickeners and acrylic emulsions onto the adsorption of thickeners will be exposed. As a result of this study, new matting agents were developed which have outstanding matting efficiency and viscosity stability, for use in thixotropic waterborne architectural coatings.