Rheological modification is often required when formulating waterborne coatings to obtain the appropriate storage and application properties. Coatings rheology is crucial because it can directly influence performance and application properties. These properties form the basis of the customer's perception of product quality.
Since their introduction in 1973, associative thickeners have captured an increasing share of the thickener market, displacing non-associative thickeners such as hydroxyethyl cellulose (HEC). The acceptance of associative thickeners has been primarily due to their ability to impart favorable rheology to waterborne coatings. However, associative thickeners are, as a class, much more sensitive to variations in coating composition than are non-associative thickeners. Changes in latex type, surfactant, or co-solvent levels, or the addition of colorants, can have a pronounced effect on paint viscosity.