Optimizing Low Foam Grind Step Surfactants for Improved Processing

By Anastasia Mardilovich Behr, Luis Madrigal, Cynthia Pierre, Gregory Monaghan, Flor Castillo

With the industry trend to low-VOC latex paints, managing foam is a significant concern for coatings formulators. APEO-free, low-foam, readily biodegradable (by OECD 301) surfactants are now available but some of these actually can be used to help defoam the grind step at elevated processing temperatures.

To optimize their use, the low-foam surfactant should be matched to a dispersant system so that the surfactant will become insoluble and act as a defoamer in the grind at temperatures above its cloud point. High throughput screening techniques were used to determine optimal combinations of dispersant and low-foam surfactant. With these leads, a follow-up study of cloud points and foaming of grind step liquids was run to demonstrate the utility of this approach.

Through careful selection of grind surfactants matched to a particular dispersant system, a notable reduction in processing foam can be achieved.