Preparation of waterborne phosphated acrylate-epoxy hybrid dispersions and their application as coil coating primer

摘要

In this paper, a series of waterborne acrylic-modified epoxy hybrid dispersions were synthesized and successfully used as primers for coil coatings. Epoxy was phosphated to improve its adhesion to the metal substrate. The grafting reaction of acrylate monomers onto the high molecular weight epoxy resins was studied with infrared spectroscopy, differential scanning calorimetry, and nuclear magnetic resonance. The structure and resin molecules were found to be as expected and the film had the best performance when the acrylate monomer made up less than 40 wt% of the epoxy resin. Modification of the epoxy with phosphoric acid could increase the adhesion to the metal substrate. Better adhesion was achieved with greater amounts of phosphoric acid. R578 urea resin was found to be the most suitable for crosslinking of the resin in this system, and a paint film based on the resulting resin had excellent overall performance.