Novel Waterborne Multifunctional Thiol- Terminated Polyurethane Dispersions for Thiol-Ene UV-Curable Coatings

摘要

In recent years, significant emphasis has been placed on the use of waterborne coatings such as polyurethane dispersions (PUDs) due to their performance and environmental compliance1. At the same, the UV curing of thiol-ene coatings systems have been shown to save energy and offer rapid curing rates for high performance coatings that do not suffer from oxygen inhibition and much higher functional group conversion2,3. A major limitation of the thiol-ene chemistry can be the storage stability, since even in the absence of UV initiation the thiols will add to enes. Therefore ultraviolet (UV)-curable waterborne PUDs coatings based on thiol-ene chemistry represent a low VOC and very effective follow up technology. It should be possible to prepare a reactive aqueous dispersion mixture in which the thiol and the ene are present in separate dispersion particles and do not see each other until coalescence. In stark contrast to non-aqueous systems or dispersions which have both reactive groups in the same dispersion particles, there will be no possibility of reaction before application. In this presentation, novel waterborne multifunctional thiol-terminated PUDs for thiol-ene UV-curable waterborne coatings were synthesized and identified, and preliminary thiol-ene photopolymerization based on resulting thiol- terminated PUDs and commercial acrylated PUDs.