Synthesis and characterization of UV curable urethane acrylate oligomers containing ammonium salts for anti-fog coatings

UV-curable urethane acrylate oligomer (UV-UAO) containing ammonium salts, suitable for anti-fog (AF) coatings was synthesized. The expected UV-UAO structure was confirmed by FT-IR and 1H NMR. This UV-UAO was then formulated with reactive monomers and photoinitiator to form coating formulas. In order to compare the UV-curing behavior of UV-UAO with conventional oligomers, the photopolymerization of UV-UAO and SK cytech EBECRYL-series urethane acrylates (EB 8210 and EB 9260) was investigated by photo-differential scanning calorimetry (Photo-DSC). The anti-fog properties of UV-cured AF coating were investigated by contact angle test and anti-fog test. Coating properties such as pencil hardness, pendulum hardness, gloss, and adhesion of the UV-cured films containing UV-UAO were investigated. The results showed that the concentration of UV-UAO in the coating formulation had a great influence on the anti-fog properties of UV-cured AF coating. Especia lly, UV-cured AF coating containing UV-UAO 65 wt.% showed excellent anti-fog properties without sacrificing other desirable properties such as pencil hardness and adhesion.