Synthesis and characterization of carboxyl group-containing acrylic resin for powder coatings

The carboxyl group-containing acrylic resin for powder coatings can be obtained by succinic anhydride reacting with hydroxyl group-containing acrylic resin, which was prepared by radical copolymerization of methyl methacrylate (MMA), n-butyl methacrylate (BMA) and β-hydroxypropyl methacrylate (HPMA) using 2,2′-azobisisobutyronitrile (AIBN) as initiator in toluene solution. The influence of synthesis method, weight ratio of monomers, and the amount of succinic anhydride on carboxyl group-containing acrylic resin was investigated. The 1H NMR results reveal that carboxyl group was successfully attached to acrylic resins. The optimum monomer weight ratio is MMA:BMA:HPMA = 65:20:15. The acid value of resin increases with the increasing of the amount of succinic anhydride, while the Tg of resin decreases.