Organic vs inorganic light stabilisers for waterborne clearcoats: a fair comparison

摘要

Today in the case of UV absorbers one has to differentiate between inorganic and organic products: the most widely used organic UVAs for coating applications are 2-(2-hydroxyphenyl)-benzotriazole (BTZ) and 2-hydroxyphenyl-s-triazine (HPT) derivatives. Inorganic products are ideally nanoparticulate materials, so called mineral screeners (MS), comprised of titanium dioxide (TiO2), zinc oxide (ZnO), or cerium oxide (CeO2). The challenge is to convert existing products, which are in general hydrophobic substances, into product forms that enable easy incorporation and un-problematic dispersion in waterborne systems. This article describes UV absorbers which are commercially available for waterborne coatings. Different classes are tested with regard to their protective function in joinery coatings as well as with regard to their influence on coatings colour and transparency.