High-Performance and Low Migration One-Component Thioxanthone Visible Light Photoinitiators

Two thioxanthone based acrylated one-component visible light photoinitiators, 2-(methyl(4(( methyl(9-oxo-9H-thioxanthen-2-yl) amino) methyl) benzyl) amino) ethyl acrylate (TX-EA) and ((4-((methyl(9-oxo-9H-thioxanthen-2-yl) amino) methyl) benzyl) azanediyl) bis(ethane-2,1-diyl) diacrylate (TX-BDA), are designed and synthesized. The results of photopolymerization and migration study demonstrate that TX-EA and TX-BDA are more effective one-component visible light photoinitiators for free radical polymerization with excellent migration stability than 4-((methyl(9-oxo-9H-thioxanthen-2-yl) amino) methyl) phenyl acrylate. The mass fraction of the extracted TX-BDA in a cured 1,6-hexanediol diacrylate polymer film is as low as 0.55% and the residual amount is estimated to be only 90 ppm. TX-BDA would have great potential to be used in visible light curing systems, particularly in the food packing or biomedical fields. Results demonstrate that the synergistic effect of hydrogen donors and polymerizable groups in photoinitiator plays an important role in realizing high performance and low migration in photopolymerization system.