Waterborne UV curable coatings – Eco-Friendly coatings - have been developed to replace conventional UV curable coatings with VOC emissions. The challenges of waterborne UV curable coatings have two aspects. One is discoloration may occur when resins are exposed to Ultra Voilet (UV) light radiation from natural sunlight. Waterborne UV-curable light stabilizers are applied to the surface for protection. The other is caused yellowing during curing process. This problem will affect customer’s product quality and therefore increase product costs.
The novel light stabilizer (NLS) is developed specifically for waterborne UV curable coats to reduce yellowing during curing process. Design of Experiment (DOE) was used in this study. Test data showed that the NLS in a waterborne clear UV curable coating would not have negative impacts to cure speed. The results confirmed that by increasing the concentration of NLS in the top coat can effectively reduce yellowing during curing process. Furthermore, data also showed that by increasing the coating thickness, the yellowing during curing process can not be improved to some degrees.