Investigation of UV-curable alkyd coating properties

Four types of UV-(meth)acrylate curable alkyds were synthesized and formulated with two tri(meth)acrylate reactive diluents. Thermal, mechanical, and coating properties, including gloss, adhesion, hardness, impact resistance, and chemical resistance, were evaluated. In general, methacrylate-based UV-curable alkyd has higher modulus and toughness, whereas acrylate-based UV-curable alkyd has better flexibility and adhesion. In all four UV-curable alkyd resin systems, increasing reactive diluent content will enhance properties like tensile strength and modulus, hardness, and chemical resistance. However, there is a decrease in properties such as elongation at break, adhesion, and impact resistance. Among four UV-curable alkyd resin, acrylated medium linseed oil alkyd exhibited the best overall performance than other systems in terms of hardness, flexibility, and adhesion. Particularly, acrylated medium linseed oil alkyd formulations with 20–30 wt% of glycerol triacrylate as reactive diluent showed the best coating performance. It is possible to produce coating films with a good balance of crosslink density, flexibility, and adhesion using such UV-curable alkyd systems. Further, it has a huge potential in alkyds as an alternative for cobalt-based drier system.