Crosslinked Cartonboard - Challenges and possibilities

Sammanfattning: The need for sustainable packaging is growing, and plastic waste needs to be reduced. A suitable alternative could be fibre-based packaging and cartonboard, and several actions could enhance this alternative. This study investigates crosslinking, a method to create stronger bonds between the OH-groups in the material. The aim is to gather information on the potential of the concept since there is previously a limited amount of research on the specific area. The goal, in the long run, is to create stronger packaging. The study will contribute with knowledge around how crosslinking can be used to enhance the strength of cartonboard and contribute to the development of more durable material. Two research questions were formulated to investigate this.  RQ1: How does the crosslinking concept affect properties of cartonboard when applied? RQ2: What effect could the crosslinking concept have on the product area cartonboard? The research has a deductive starting point, and the project planning was agile, which allowed the study to form as the results gave new intel about the concept. The focus is on collecting qualitative data with high validity, which has been done by testing the material according to different standards. The material investigated is a folding boxboard (FBB) in four separate grammages to give an overview of the effect of the concepts. Properties evaluated include short span compression test (SCT), tensile strength, recyclability, cobb and box compression resistance tests (BCR), and more.  The results show a slight increase in SCT for the highest, 460 gsm, and lowest, 245 gsm, grammages of the materials used in this study. The recyclable is affected minimally with only a few per cent, but it remains high. However, the material becomes a bit stiffer and suffers losses in tensile strength, elongation, and tensile energy absorption. The enhanced strength seen in SCT does not show for BCR. The crosslinked material tends to crack in the creases before and after bending, especially in the highest grammage. The Cobb results indicate crosslinking shows potential to be used as a barrier to make the material more water repellent.  Conclusions drawn from the results are that even though the SCT value is enhanced for two grammages, it suffers losses in tensile strength, and the strength enhancement does not show for BCR. Therefore, the impact on the product area is not clear, and further research is recommended to understand the area more.  Suggestion for further research is to do more research in the area in general and then scale up the study to a pilot study. This would gain intel on how the concept will work in a non-laboratory situation and investigate how it could be implemented in production