One of the challenges of formulating waterborne architectural coatings is achieving an acceptable balance of properties both during application and in the final film. Over the past decade, this has become increasingly more difficult because of the significant changes in VOC regulations. Although VOC definitions differ from region to region, the propylene and ethylene glycol used to improve open time and wet edge are universally considered to be VOCs. Since glycols are one of the primary VOC sources, they are often reduced or eliminated in lower-VOC paints, thus compromising open time, wet edge and paint workability. This creates the need for a solution that enhances paint workability without contributing significant VOCs and without negatively impacting film properties such as scrub resistance and wet adhesion.
This article describes a new, low-VOC additive that improves open time, wet edge and workability in low-VOC latex paints. Paint performance properties are demonstrated in a typical architectural formulation, and mechanisms for the enhanced performance are outlined through use of novel rheological techniques.