Amine-based chemistries such as N-methyl diethanolamine (MDEA), ethyl-4-dimethyl aminobenzoate (EPD) and 2-ethylhexyl-4-dimethylaminobenzoate (EHA) are well known and used widely in UV-curable coatings to reduce surface tackiness by counteracting the impact of oxygen quenching. While working with UV-curable coatings using benzophenone and an amine synergist, a new type of synergist was discovered that showed marked improvements in polymerization kinetics, depth of cure and yellowing.
This new, patent-pending chemistry has been found to improve depth of cure and promote such an improved kinetics of polymerization that the photoinitiator concentration in our model system could be reduced by as much as 50% with no appreciable difference in properties. What’s more, these advantages have been demonstrated in both Norrish Types I and II systems.