PREPARATION OF UV CURABLE EMULSIONS USING PEG-MODIFIED URETHANE ACRYLATES AND THEIR COATING PROPERTIES .3. EFFECTS OF EPOXY ACRYLATE

Water-dispersible UV-curable urethane acrylate emulsions were prepared with polyethylene glycol (PEG) - modified urethane acrylates (PMUA), containing terminal hydrophilic polyoxyethylene chains. To improve phy sical properties of PMUA, epoxy acrylate (EA) having high thermal stab ility and hardness, was mixed with five kinds of PMUA containing diffe rent chain lengths of polyoxyethylene (POE). For PMUA/EA. mixtures, th e composition ratio of EA to PMUA and the chain length of POE greatly influenced the size of droplets of emulsions and the physical properti es of their cured films. At higher EA. to PMUA ratio, the physical pro perties decreased, which was due to phase separation between EA and PM UA. Phase separation was confirmed by scanning electron microscopy.