Biodegradation of UV Curing Thermochromic Prints with Respect to Printing Substrate

Abstract

Amount of packaging waste is constantly increasing, resulting in different environmental problems. Packaging waste, mainly plastic and paper based, comprises about one-third of all municipal solid waste. Anaerobic degradation is common method of the waste management for the organic based materials. In this study, biodegradability potential of UV curable thermochromic ink, as most common sample od smart packaging, was studied. The used ink is based on polyurethane acrylate.. Results indicated that by the proper selection of materials the biodegradability aspect of printed samples can be varied. Moreover, the results point to heterogeneous degradation of prints surface. This can be confirmed by the determination of the prints’ total colour difference, which was relatively high in all cases pointing to print deterioration. Biodegradation of UV TC ink, based on polyurethane acrylate results in breaking down of the ester linkages i.e. due to the hydrolysis of the ester bonds. Within the used printing substrates, TC print on wood free uncoated paper shows the highest rate of biodegradation over 150 days of incubation, around 40%, followed by print on 100% recycled paper and wood free coated paper. The present study shows that TC prints in studied environment, are ultimately biodegradable.