TAGS: Sustainability / Natural Adhesives
Fraunhofer Institute for Manufacturing Technology and Applied Materials Research IFAM in Bremen and the Plastics Center SKZ in Würzburg launched a research project that aims to also feed thermally damaged plastics into the circular economy via chemical recycling. The material of choice is PET, which is already very well established in mechanical recycling.
Develop Continuous, Reactive Recycling Process
Due to the well-known bottles and due to the associated deposit system in Germany, the material here is mostly unmixed, most of which is already being efficiently recycled. The RezyBond project wants to address the PET fractions that have aged too much due to several recycling processes or that do not end up in this (bottle) cycle at all, such as other PET packaging. The chemical recycling in this case is carried out on a standard twin-screw extruder.
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Our goal is to develop a continuous, reactive recycling process from PET recyclates to polyester polyols. These are then used again as chemical starting material," explains Hatice Malatyali, group manager for extrusion and compounding at SKZ.
Recycled Polyols as Raw Material for Adhesives
The polyols obtained serve as a raw material for a wide variety of technological areas, such as adhesives or paints. In the project, these are to be used as starting materials for adhesive formulations and thus transferred directly to an application. A demonstrator system is also planned at the SKZ to make the process accessible to interested medium-sized companies.
Mechanical recycling is now an established technology. Unfortunately, the plastics to be recycled are usually not available in a single type. The consequence is recyclates that consist of a mixture of different plastics and the associated losses in material properties. The result is often downcycling, i.e. the use of this recyclate in other (inferior) applications.
In addition, there is a certain amount of damage to the material with each recycling cycle, which also negatively affects the properties of the plastics. In order to integrate these two cases into the
circular economy, chemical recycling is considered a possible solution. Here the polymers are degraded down to their base materials, in order to then be recycled with little use of new raw materials without loss of quality.
Source: SKZ