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 m onths of Florida or accelerated weathering testing. Because of this excelle nt weathering, better short term tests are needed to predict long term weat herability. 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 under stand the microscopic basis for these differences. For new fluoropolymer/ac rylic blend compositions, the weight loss rate can be used as an early pred ictor of the blend's weatherability. (C) 2000 Elsevier Science S.A. All rig hts reserved.