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The UV curing process entails the use of
a UV lamp that drives the light onto the surface covered with
a liquid formulation containing the photoinitiator. The photoinitiator
generates radicals that convert the formulation into a solid,
cured film. The formulation is based on monomers, acting also
as reactive diluents, and oligomers. The monomers and oligomers
are generally derivatives of acrylate/methacrylate, containing
polyurethanes, polyesters or polyethers. The type of oligomer
characterises the properties of the final product.
The photoinitiator is the key of the curing process because
it starts polymerisation and cross-linking reaction. Under
UV irradiation the photoinitiator fragments into free radicals
that are the reactive species for the polymerisation of unsaturated
moieties. |
