Synthesis of UV-curable polyesters with lateral double bonds by ring-opening polymerization and their properties

UV-curable coatings have been receiving more and more attention for their high performance and environmentally friendly advantages, which meet the “5 E” requirements of coating development. Vinyl oligomer is the main factor affecting the performance of UV-curable coating, but it is difficult to meet the requirements of high-end UV curing technology due to its high viscosity, low vinyl functionality, and high cost. Herein, polyesters with lateral double bonds were prepared by ring-opening polymerization of acid anhydride and glycidyl methacrylate. The epoxy compound without vinyl groups was used to participate in the polymerization reaction to adjust the viscosity and vinyl functionality of the resin. Furthermore, the molecular structure and molecular weight of the polyesters were characterized by FTIR, ¹H NMR, and GPC. The effects of the categories and proportions of acid anhydride and glycidyl ether on the viscosity and hardness of the coating films were studied. The results indicated that the use of acid anhydrides containing phenyl rigid groups could significantly increase the hardness of the paint film, and the long-chain tertiary glycidyl carbonate (E10P) had the best viscosity reduction effect. When the molar ratio of acid anhydride, GMA and E10P was 4:1:3, the viscosity of the prepared vinyl polyester was low to 2755 mPa·s. In this case, the hardness of the paint film was as high as H, and it also exhibited excellent water resistance and alcohol resistance.