Colloquia

Summary

Mono-materials have a potential to have a high recyclability performance [1-5]. The main reason for this is that mono-materials do not require material separation of the packaging system during the sorting, like multi-material alternatives require [2, 6]. Sealing mono-materials however can form a challenge. Conventional heat sealing technology reaches its limitations when trying to seal mono-materials, due to their small sealing window and the large temperature fluctuations associated with conduction sealing. Ultrasonic sealing is more suitable to seal mono-materials since it heats the materials at the seal interface. A new and successful combination is ultrasonic sealing implemented in an HFFS system. This raises the question whether other sealing technologies might be applied in HFFS system and when. To answer this question, sealing technologies need to be compared.

This thesis proposes a framework that compares different types of heat sealing technologies with a HFFS system application. This framework can be used to select the proper type of sealing for a certain application. The sealing technologies are compared based on different parameters. These parameters together will indicate where the main differences between the sealing technologies lie and will form a base for a well-founded choice. The focus lies on conduction and ultrasonic sealing. These two types of sealing are most used in practice [7]. Especially conduction sealing is used extensively and has a large amount of scientific papers written about it. Ultrasonic sealing is newer and tests have been performed to fill in the framework for this sealing technology. 

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2. Nonclercq, A., Mapping flexible packaging in a Circular Economy. Final Report, 2016.

3. KIDV, Achtergronddocument KIDV Recyclecheck Flexibele Kunststof Verpakkingen 2023. 2023.

4. CEFLEX, DESIGNING FOR A CIRCULAR ECONOMY. 2023.

5. Hauptmann, M., et al., The effect of flexible sealing jaws on the tightness of pouches made from mono‐polyolefin films and functional papers. Packaging Technology and Science, 2021. 34(3): p. 175-186.

6. Kaiser, K., M. Schmid, and M. Schlummer, Recycling of polymer-based multilayer packaging: A review. Recycling, 2017. 3(1): p. 1.

7. Nase, M., et al., Fracture mechanics characterisation of peelfilms. Deformation and Fracture Behaviour of Polymer Materials, 2017: p. 271-281.