Improving Exterior Architectural Paint Performance and Surfactant Leaching Through Binder Modification
D.J. Christensen, Chemist, EPS
Under certain weather conditions, humidity can cause the exudation of water-soluble paint formulation components, which leaves an aesthetically unattractive residue on newly painted dry films; a phenomenon known as surfactant leaching. Resisting surfactant leaching in exterior architectural paints has been a challenge for formulators as the industry adjusts to stricter VOC regulations. In this study, a design of experiment was run to better understand the binder composition factors that affect the resistance to surfactant leaching in exterior flat paints. In order to evaluate the coating performance, a new method to quantify the exudate was developed, which led to the identification of more complex interaction terms that were not found using conventional methodology based on evaluation by water spot testing. The conclusions have led to the development of an optimized resin technology that not only has resistance to surfactant leaching, but also resistance to dirt pickup, tannin stain blocking and efflorescence.