Predicting the exterior durability of new fluoropolymer coatings

Commercial coatings based on polyvinylidene fluoride (PVDF)/acrylic blends typically show minimal gloss loss or bulk chemical change even after many months of Florida or accelerated weathering testing. Because of this excellent weathering, better short term tests are needed to predict long term weatherability. We have recently found dramatic differences in the steady state weight loss rate for different fluoropolymer/acrylic coatings in a ‘QUV-B’ unit. For clear coats, steady state weight loss rates can be measured long before the coatings begin to lose gloss. Studies are now underway to understand the microscopic basis for these differences. For new fluoropolymer/acrylic blend compositions, the weight loss rate can be used as an early predictor of the blend’s weatherability.