Accelerated aging methods to study color retention of organic renders

 
Colorful and dark exterior coatings are gaining popularity in modern design of buildings. With intense colors it is challenging to maintain good aesthetic appearance over 5-10 year lifetime. The technical challenges imposed are multidimensional and root-causes include dye and binder degradation, while also dirt-pick up and efflorescence may play a role. To compare the performance of products that address the above issues, outdoor exposure studies over several years give the most reliable results. However, outdoor exposure studies take too long for product development, therefore accelerated laboratory test methods are used as a valuable tool to guide product development efforts. In this presentation we compare different accelerated weathering methods to study color retention in façade coatings. Parameters include different fillers, acrylic binders, additives, and inorganic or organic tints. We also present an accelerated method to study dirt-pick up resistance showing good correlation to exterior exposure results in a Mediterranean climate zone.