Weathering characteristics of epoxy-ester paints

The diglycidyl ethers of bisphenol A (DGEBPA), bisphenol F (DGEBPF), bis 2,6-xylenol F (DGEBXF), bis 2,6-xylenol S (DGEBXS) and biS 2,6-xylenol (DGEBX) were converted to epoxy-esters by reacting them with dehydrated castor oil fatty acid (DCOFA). Simple TiO2 paints were prepared using the epoxy resins as well as their epoxy-esters and compared for the weathering characteristics by subjecting them to accelerated and environmental weathering. The weathering characteristics of the epoxy-ester paints were found to be better than their corresponding epoxy paints cured with amine terminated dimer fatty acid based polyamide (FPA). The paint prepared with DGEBPA modified with DCOFA and cured with Co and Pb octoate gave the best weathering characteristics with appreciable improvement in chalk resistance, optimum yellowing and gloss retention.