Photoinitiator 369 (2-Benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone)

Alpha-aminoketone photoinitiators (PI-369, PI-907) generate both benzoyl and amino radicals upon UV exposure, providing high polymerization rate even in oxygen-containing environments. PI-369 absorbs strongly at 369 nm (near UV-A), where TiO2 and carbon black have lower optical interference than at 254–310 nm. In deeply pigmented or filled systems, longer wavelength absorption enables deeper penetration into the coating, achieving full through-cure without surface over-exposure. Often combined with PI-819 (acylphosphine, deep cure) for optimal surface and through-cure balance.