New waterborne UV durable acrylic-epoxy hybrid coatings without the need of topcoat for metal protection

 
Epoxy coatings are often used in applications over metal substrates due to their excellent performance properties, including corrosion resistance and chemical/solvent resistance. Inadequate properties of epoxy chemistry often include poor UV light durability, brittleness, poor gloss/color retention, flexibility and impact resistance. Many epoxy coatings also contain solvents which contribute to high volatile organic content (VOC) levels. Waterborne epoxy coatings can often be formulated to lower VOC, but exterior durability and flexibility still remain a challenge. This paper will describe a new waterborne acrylic-epoxy hybrid polymer that enables formulation of 2K metal primers and DTM finishes with this important balance of properties. This versatile system can be cured with either traditional waterborne amine hardeners or with acid-functional acrylic hardeners. Performance of the waterborne acrylic-epoxy hybrid technology, in gloss DTM finishes as an alternative to replace 2k epoxy primer + 2k PU topcoat will be described in this paper.