In the All-Polymer project, you researched exactly that. What were the goals?
Rathgeber: The goal of All-Polymer is to add value to secondary plastics by means of cost- and energy-efficient unidirectional (UD) fibre-reinforced tapes (UD tapes), which are either applied to a component using an additive tape-laying process for local reinforcement or integrated into a component as inserts in injection moulding or compression moulding processes. Instead of using energy- and cost-intensive glass and carbon fibres, the innovative approach is to use plastic fibres. These can be produced in an extraordinarily energy-efficient way, are sorted according to type and are completely recyclable.
How did you go about your research?
Rathgeber: The potential to use recyclates from one application in another high-value application was investigated using use cases from different industries. Here we focused on important key industries such as automotive (Röchling Automotive), logistics (Infinex Holding) and agriculture, forestry and construction (Hahn Kunststoffe). The start-up A+ Composites produces UD tapes with the plastic fibre Dyneema®, which are unique worldwide according to the fibre manufacturer DSM.
By investigating the tape-component adhesion as well as by means of mechanical characterisation, the requirements for the various applications could be identified and the UD tapes and component properties adapted. The connection between the component and the UD-Tape was made using a welding or pressing process, depending on the application. Both processes could be significantly improved through the cooperation and adapted to the requirements of the components. Stable processes leading to well adhering tapes were realised.
An examination of the ecological and economic framework conditions by the Technical University of Kaiserlautern (Chair of Sustainability Management) supported the technical development. The status quo of the participating companies in the Circular Economy could be recorded through an accompanying circularity assessment. In addition, potentials were identified through which the project participants can position themselves even more sustainably in the future. For one of the use cases, a life cycle analysis including a CO2 balance was also prepared.