Converting and its Effects on Barrier Properties of Coated Packaging Materials: A Review

Considerable research is ongoing, examining opportunities for substituting plastic packaging with more sustainable alternatives, and some encouraging results have been achieved. Coated paper and paperboard demonstrate promising performance; however, several serious drawbacks still need to be overcome. Recent research in this area is reviewed in the current work, including mechanical and machinery aspects of paperboard converting, as well as barrier properties of coated materials before and after processing. The main objective of the study was to establish how coated paperboard behaves during converting operations and investigate what changes in its properties occur, considering not only the convertibility of the material as a whole but also effects on substrates and coatings. The results of the literature review show that creasing, folding, and the presence of forming stresses severely damage barrier and pigment coatings even if the paperboard-based product is reported as having good oxygen and water vapour barrier or oil resistance after production. Thus far, most materials cannot fully match the performance of plastic packaging materials due to a noticeable reduction in barrier properties after converting. The work presents factors linking the convertibility of coated materials and their subsequent barrier properties as valuable knowledge to support future development of sustainable materials.