Relationship between crosslinking and surface mechanical properties of UV curable coatings for automotive interior plastic parts

UV curable coatings for automotive interior plastic parts are composed of acrylate monomer and urethane acrylate oligomer. In this study, the real-time UV curing behavior and the mechanical properties of the coating surfaces were scrutinized by adding additives such as photoinitiator, UV stabilizer including UV absorber and HALS, and matting agent to UV curable coatings. The curing behavior of UV curable coatings was interpreted based on the changes in surface properties, depending on the applicable actual curing conditions. The curing behavior was checked by a rigid-body pendulum tester and FTIR. The mechanical properties of coatings, such as hardness and scratch resistance, were measured via nano-indentation and nano-scratch testers. The optimum curing conditions were selected using measurement tools and the role of the additives for establishing the correlation between the curing dynamics of coatings for interior plastic parts and properties of cured films was systematically elucidated.