The recycling of intelligent cardboard packaging was the subject of our master's thesis. We were interested in the impact of a printed RFID antenna and a thermochromic indicator on the recyclability of cardboard packaging printed with the digital printing technique. The aim of the study was to produce and recycle cartons incorporating printed electronics and to assess their recyclability. In the theoretical part, we presented intelligent packaging, its importance and development. We focused on two factors of intelligent packaging, i.e., printed electronics and thermochromic ink. We also included the circular economy, of which recycling is a large and important part, presented the recycling and deinking processes of cardboard packaging, and analysed the state of the art of the research. For the recycling process, we used the Confederation of European Paper Manufacturers' (CEPI) method, which was also used at the end to determine the recyclability by dissolving the samples and then determining the coarse residue by means of a coarse screening process. The concentration after the coarse screening was also determined and handsheets were produced on which the adhesiveness test and visual assessment were carried out. This was repeated with the fine screening process. The deinking process was carried out according to the INGEDE method, using handsheets of the test product. The handsheets obtained were tested for basic, mechanical and optical properties.
We have concluded that the recyclability result for all the tested samples was very high, showing that all samples are suitable for the standard recycling process. Moreover, the recycling efficiency is above 99% for all samples. Although there were variations in the samples with printed electronics containing functional and thermochromic ink, they had no major effect on the final result. This has confirmed the hypothesis that the packaging will recycle well and that the printed electronics and thermochromic ink will not have a major effect on recyclability. We have also detected a difference in recyclability between printing the intelligent elements directly on the cardboard or on the label, and confirmed the fact that the packaging will be suitable for the deinking process.
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