Foam can create many problems in manufacturing, application, and performance of waterborne paints and coatings. Therefore, defoaming additives are included in formulations to prevent or eliminate foam and its associated problems. Although defoamers can have positive effects on the performance of a coating, use of a defoamer that is not suited for the specific formulation and application can cause even greater problems. Furthermore, identifying the optimal defoamer for a given application can be time consuming and complex because of the multitude of factors that affect defoamer performance. Defoamer performance is controlled by the chemistry and formulation of the additive, as well as many formulation, application and manufacturing variables such as type of agitation, application method, coating ingredients and chemistry, pigment volume concentration, coating viscosity, application thickness, and drying time. However, it is possible to predict a defoamer's performance in different types of coatings and applications based on its chemistry and formulation. This paper will discuss how the design of defoamers can affect performance in coating formulations and provide examples of how these designed defoamers can be utilized to select an optimal defoamer for coating formulations and applications.
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