UV curing consists of a polymerization reaction that transforms a liquid resin into a solid film within a fraction of a second under the action of light. This technology is an effective alternative to conventional printing processes, which commonly involve the use of solvents, and it simultaneously addresses economic and environmental concerns.
However, some well-known UV-curing issues still remain to be tackled, e.g., migration of unreacted materials, a potential health hazard, particularly in indirect food contact applications, where components could migrate from the packaging into food. It is of primary importance to find solutions to prevent migration, especially since there is a clear trend today toward reducing multi-layer packaging – for environmental reasons – and, therefore, care must be taken to ensure suitable material selection, curing conditions and printing processes. This paper reports on the influence of curing conditions and photoinitiator migration, with a special focus on photoinitiator structure, UV dose and curing atmosphere.