Journal of Applied Polymer Science, Vol.102, No.6, 5566-5570, 2006
UV-curable methacrylic epoxy dispersions for cationic electrodeposition coating
UV-curable epoxy dispersions were prepared for cationic electrodeposition coating. Sequential reactions were used to introduce methacrylate groups to the epoxyamine polymer as coupling agents to the multifunctional acrylates. The molecular weight values of the prepared epoxy-amine polymer were M-n = 2800 and M-w = 4300. The neutralized epoxy-amine polymer containing photoinitiator with or without multifunctional acrylate (pentaerythritol triacrylate, PETA) could be dispersed into a stable dispersion without any phase separation. The size of the particles in these epoxy dispersions was approximately 77.7 nm, and increased with the incorporation of PETA. The electrodeposition process was introduced to the prepared epoxy dispersions, and the electrodeposited films were cured by UV irradiation after a 10-min flash off at 80 degrees C. Studies of the kinetics using photo-DSC revealed that the crosslinked films containing PETA gave a higher conversion rate than those without PETA, resulting in better resistance to methyl ethyl ketone. (c) 2006 Wiley Periodicals, Inc.