Old plastic becomes new adhesive

A recently launched research project by the Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Bremen and the SKZ Kunststoff-Zentrum in Würzburg aims to feed thermally damaged plastics into the circular economy through chemical recycling.

The material of choice is PET, which is already very well established in mechanical recycling. Due to the well-known bottles and the deposit system in Germany, there is mostly pure material available, which is already efficiently recycled for the most part. The RezyBond project is dedicated to PET fractions that have aged too much through several recycling processes or do not end up in this (bottle) cycle at all, such as other PET packaging.

What is special about the process is that in this case the chemical recycling is carried out on a standard twin-screw extruder. “Our goal is to develop a continuous, reactive recycling process of PET recyclates into polyester polyols. These then serve as chemical feedstock again,” explains Hatice Malatyali, group leader extrusion and compounding at SKZ. The polyols obtained serve as basic materials for a wide variety of technological areas, such as adhesives or lacquers. In the project, these are to be used as starting materials for adhesive formulations and thus transferred directly into an application. A demonstrator plant is also planned at the SKZ to make the process accessible to interested medium-sized companies.

Further information can be found on the SKZ website.