The Impact of Microfibrillated Cellulose on the Rheology of Water-based Acrylic Satin Paint upon Tinting

By Otto Soidinsalo, Harrison C. Gallantree-Smith, Scott Mouw, Borregaard AS

Associative thickeners are commonly used to thicken water-based coatings. Their mechanism of action is based on the hydrophobic interaction between the hydrophobic polymer groups as well as with the surface of the binder latex particles. It is commonly known that associative thickener-based formulations are prone to viscosity loss upon tinting due to the surfactants present in the tinting systems, leading to poorer sag resistance. In this work, the effect of an insoluble microfibrillated cellulose (MFC) was studied on the prevention of viscosity loss on tinting with a deep tone base, formulated with two different hydrophobically modified polyurethane associative thickeners (HEURs), combined with a non-associative MFC thickener. The formulations were evaluated in terms of rheology, viscosity, sag resistance, flow/leveling, and gloss.