Synthesis of of blocked waterborne Acrylic-Urethane resin and investigationthe effect of crosslinking on hardness and adhesion in furnace primers

In recent years, water-based polyurethanes have gained increasing popularity due to their ability to reduce theamount of pollution released into the environment by solvents. In this study, semi-block isocyanates are used inorder to synthesize a urethane-acrylate monomer. A water based blocked acrylic-urethane resin was subsequentlysynthesized by emulsion polymerization technique in accompany with other acrylic monomers. As the polymerchain cures in the oven, its blocking agent is released, forming cross-links with other functional groups. DLS andZETA potential were used to evaluate the stability and particle size of polyurethane-acrylic emulsion systems. Basedon the results of the tests, it was determined that as the amount of urethane-acrylate monomer increases, the size ofthe emulsion particles also increases and nevertheless the stability of the emulsion also improves. Additionally, thehardness, glass transition temperature, chemical resistance, and adhesion of cured films are compared by changingthe concentration of this monomer in the formulation. It was demonstrated that the hardness of the coating film, theglass transition temperature, water resistance, chemical resistance, adhesion, and tensile strength of the filmsincreased significantly with the increase in the percentage of urethane acrylate monomer. All measured parametersindicated the proper reactions of deblocking and crosslinking at elevated temperature.

کلیدواژه ها:

Emulsion polymerization ، Urethane-acrylate monomer ، Water based polyurethaneacrylic ، Semi-blocked isocyanate ،