Coatings for exterior surfaces are exposed to a variety of destructive mechanisms -UV, moisture, temperature extremes, biodegradation, etc.. While dirt pick up may not be the most destructive mechanism it can provide sites for mold and mildew growth and look unsightly. Existing easy-to-clean additives are based on fluorosilanes and polysiloxanes which migrate to the surface of the coating but have limited binder compatibility and will lose effectiveness over time. One alternative strategy to generate permanent easy-to-clean effects is based on nonionic monomeric and polymeric fluorinated surfactants that can be used in a wide range of coatings applications. Such additives have additional acrylic- and hydroxyl- functionalities which can cross-link into the binders of a variety of waterborne and solventbome coatings systems for permanent dirt repellency and easy water clean-up. We have recently expanded the concept by developing alternative chemistry based on functionalized polysiloxanes to replace fluorine - early data indicates a strong permanency effect coupled with the easy-to-clean effect.
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