Migration of substances from layers cured by UV radiation

Abstract

This paper is focused on migration of substances (photoinitiators and monomers) from formulations cured by UV radiation. The very effective and more often used solution for study of migrating substances into foodstuff is coupling of separation chromatographic techniques (liquid chromatography, gas chromatography) with mass spectrometry. In this work, samples containing only monomer and photoinitiator were cured under different conditions. After evaluation of monomer conversion (FTIR spectroscopy) amount of substances that migrated from cured sample into simulant (acetonitrile) by UV/VIS spectroscopy was estimated. The tested initiators were free radical photoinitiator (1-[4-(2-hydroxyethoxy)-phenyl]- 2-hydroxy-2-methylpropan-1-on) and cationic photoinitiator (05-2,4-cyclopentadien- 1-yl)-[(1,2,3,4,5,6-h)-chlorobenzene]-Fe(II)-hexafluorophosphate). Acrylate binder pentaerythritol triacrylate and epoxy binder (3,4-epoxycyclohexylmethyl- 3,4-epoxycyclohexane-carboxylate) were used as monomers. The study proved that UV-VIS spectroscopy is a suitable method for analysis of simple systems consisting of a small number of components (two or three). The disadvantage of this method is that in comparison to chromatographic methods it cannot separate and identify a complex mixture of substances. Therefore, UV/VIS spectroscopy is not suitable for evaluation of migrants from commercially available inks and varnishes, which contain a large number of components (monomers, oligomers, initiators and additives).