Comparison of Physical Properties of Coatings on Paper Substrate after Curing by UV and Electron Beam

This study aimed to assess the curing efficacy of ultraviolet (UV) radiation and electron beam (EB) curing techniques and the physical attributes of coated overprint varnish (OPV) applied on paper substrates. Coating formulations with and without photo-initiator (PI) underwent UV irradiation at doses ranging from 0.561 to 1.612 J/cm2 and EB at doses ranging from 30 to 100 J/g. The investigation utilized Fourier-transform infrared (FTIR) spectroscopy to analyze the degree of conversion of double bonds in the cured samples, with a notable absorption peak observed at 810 cm-1 corresponding to C=C bonds in the acrylate group. Furthermore, EB curing exhibited polymer curing percentages ranging from 79% to 83%, similar to UV curing. Notably, the yellowness index of EB-cured coating films (ranging from 0.5 to 10) was lower than that of those cured with UV (ranging from 10 to 28). The study suggests that EB curing could serve as an alternative process, potentially reducing health hazards associated with photo-initiator migration and food contamination within packaging materials, thereby offering a promising future for the field.