Co-polymerisable photoinitiators

The types of photoinitiators used in the UV-curing industry are now well es tablished as is the mechanism by which each type initiates a polymerisation reaction. The fate of the unreacted photoinitiator and that of the breakdo wn products arising from exposure to UV is. becoming of increasing importan ce in many applications these days and this will be considered in this pape r. Experimental results will be presented comparing the relative performance o f photoinitiators that has been built into the backbone of a resin with tho se added in the 'free' state. The versatility of urethane chemistry to buil d in the photoinitiator will be illustrated, particularly for water-based U V-curable dispersions.