Preparation and characterization of a novel ultraviolet/thermal dual-curing thiol-ene/polyurethane acrylate coating

A novel ultraviolet (UV)/thermal dual-curing thiol-ene/polyurethane acrylate (PUA) coating of PUA oligomer, tripropylene glycol diacrylate, 2,4,6-trimethylbenzoyldiphenyl phosphine oxide, and trimethylolpropane tris (3-mercaptopropionate) was prepared. The coating had a rapid surface drying rate with UV radiation (400 W, 50 W/cm(2)). For example, the surface of the novel thiol-ene/PUA coating dried within 3 s. The hardness, gel content, and initial decomposition temperature at 5 wt% weight loss of the UV/thermal dual-cured sample after 10 min of UV irradiation, followed by heating at 150 degrees C for 20 min, were 37 D, 90.3%, and 302.2 degrees C, respectively, which were higher than the 30 D, 87.7% and 284.9 degrees C of the UV curing control after 10 min of UV irradiation. The curing time of the 1-mm-thick coating was 4.5 min in indoor sunlight (2.3 +/- 0.3 mW/cm(2)) with a gel content of 83.8%. This coating could be applied in the rapid prototyping field with UV or sunlight exposure. Thermal treatment after UV curing could increase the crosslinking degree and influence the sample performance.

Automated summary

A novel ultraviolet/thermal dual-curing thiol-ene/polyurethane acrylate (PUA) coating was prepared, showing rapid surface drying rate and high hardness. It could be used in rapid prototyping field with UV or sunlight exposure, demonstrating potential application prospects.