Defoamer Selection in Waterborne Coatings

By Robin A. Reinhardt, Wernfried Heilen, Ellen Walhorn, Stefan Silber, Jay W. Adams

Waterborne coatings systems differ from solventborne systems in a number of ways. One key difference is the fact that water displays a high surface tension, which must be lowered to allow spreading over low-energy substrates.

But solving this problem often leads to another problem: the surfactants used to lower surface tension tend to stabilize foam. This foam, in turn, must be destabilized during manufacture and application through the use of a defoamer.

Choosing the proper defoamer for any given system has always been a matter of empirical selection. But today, new methods of analysis can help with that selection process. This article presents new and existing research in the areas of foam control and defoamer selection that can help minimize the amount of empirical work needed.