Exterior Durability Evaluation of Ambient Cure Fluoropolymers

摘要

Over the past 30 years, coatings based on the homopolymer of Poly(Vinylidene Fluoride) (PVDF) have set the standard for exterior durability in factory-applied coatings. Since the introduction of PVDF homopolymer for coatings in the 1960's, the number and types of fluoropolymers for coatings has continued to increase. Unlike the PVDF homopolymer, many of the new fluoropolymer resins are capable of forming films at ambient temperatures, thereby offering the possibility of field-applied coatings with outstanding durability. In addition, the waterborne emulsion fluoropolymers now afford the opportunity to formulate low VOC coatings for field application. The actual performance of these new fluoropolymers has been unknown, except based on chemistry and artificial weathering test data. In this study, ten fluoropolymers were exposed at outdoor test sites and compared to PVDF to assess their weathering characteristics. Color retention, gloss retention, chalking, and dirt resistance were measured and compared to commercial PVDF coatings inpigmented formulations. Initial results indicate that some of the new fluoropolymers will meet or exceed the high weathering standards that their PVDF predecessor has set.