Mapping of Material & Conversion Parameters of Packaging Production – Boardio®

Sammanfattning: With an increased demand for sustainable packaging solutions for the ever-growing FMCG market, fiber-based systems rise as an answer to phasing out plastics in packages and reducing the humanity’s climate footprint. However, constructing a packaging solution largely consisting of paperboard comes with its challenges, such as integrating functionalities in the anisotropic paperboard that formerly were provided by a fundamentally different materials with divergent mechanical properties, being isotropic polymers. In the pursuit of a fiber-based packaging system, Boardio® was created. Three different commercial paperboards with different mechanical properties together with three different laminate structures, creating nine paperboard laminates in total, were studied. The main objective of this thesis was to investigate how different laminate structures, together with machine parameters affect the crease height and strength of the perforations in the Boardio® solution. The work was centred around quantitative analysis through tensile strength testing of laminate substrates and thickness measurements of paperboard laminate creases, together with separate qualitative analyses through optic microscopy and x-ray tomography. Opposed to the ideal theoretical behaviour and mechanics of paperboard laminates and perforations which gain strength when adding more components such as PE-film and aluminium foil to the laminate, it was found that thicker laminates yield in lower, but less fluctuating, perforation strengths than laminates without PE-film and aluminium foil. The lower strength is related to the higher degree of rupture in the paperboard of the perforations, validated with x-ray tomography. Through this qualitative method of validation, it was possible to identify a total rupture in the paperboard of full laminates, being laminates with the structure paperboard/PE /al-foil/PE/PE-film, most plausibly caused during the formation of creases in the die-cutting process, which induces large stresses in the paperboard laminate. This additionally strengthened the importance of including a layer of PE-film to obtain satisfying, nonfluctuating, perforation strength. Further, the strength of the perforations is strictly governed by the degree on non-ruptured fibers in laminates without PE-film, making it challenging to reach non fluctuating perforation strength during large volume productions of these laminates. It was also found that thicker laminates yield in deeper creases during the die-cutting process, enabling better folding, and finishing of the Boardio® packages.