Synthesis and application of water-soluble hyperbranched polyester modified by trimellitic anhydride

In this paper, we aimed to synthesize a water-soluble hyperbranched polyester with pentaerythritol and trimethylolpropane as branching centers and trimellitic anhydride as waterborne functional groups. The condition and principle of water-soluble hyperbranched resin synthesis were explored. The trimellitic anhydride was used to synthesize water-soluble hyperbranched resin at the most appropriate temperature of 160–170°C. The properties of the resin were characterized by FTIR, hydroxyl value, molecular weight, stability, viscosity, and then the relationship among them under different synthesis conditions was further studied. Results indicated that the water-soluble hyperbranched resin had no delamination for more than 6 months at a solid content higher than 60%. Moreover, the resin was mutual soluble with water at any proportion and kept clear and transparent at same time. After water-soluble hyperbranched resin mixing with amino resin in a ratio of 2.5:1, and curing at 130–135°C for 2 hours, the chemical and mechanical properties of the coating were further measured and characterized.