{HEAD ~ 0.5 wt %} of {TAIL ~ 2,4,6 trimethylbenzoyldiphenylphosphine oxide type photoinitiator} 
of
{ HEAD ~ 0.5 wt % } of { TAIL ~ 2,4,6 trimethylbenzoyldiphenylphosphine oxide type photoinitiator }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL