The project “ReProOrgano” was carried out from 1 September 2019 to 31 December 2022 under the German Federal Ministry of Education and Research’s framework programme “Research at Universities of Applied Sciences with Companies (FHprofUnt 2018)”. The project carrier was VDI Technology Center GmbH, and the research was conducted in close cooperation with the Technical University Rosenheim and the industrial partners Bond‑Laminates, Brose, ElringKlinger and KraussMaffei. The aim was to develop a closed‑loop recycling strategy for the nesting waste generated during the production of hybrid injection‑moulded components made from endless‑fiber reinforced thermoplastics, also known as organoblech. In the automotive sector, where lightweight construction is increasingly driven by fuel‑efficiency and CO₂‑emission targets, the use of such composites has become widespread. However, the nesting process that shapes the raw material into the required geometry can produce up to 35 % waste. Until 2020 this waste was typically burned in energy recovery plants or processed into regranulate, which caused a significant loss of fibre length and consequently a reduction in mechanical performance – a phenomenon referred to as down‑cycling.

The technical work of the project focused on retaining the mechanical properties of the recycled material while enabling its direct use in the hybrid injection‑moulding process. The waste was first crushed into a fine powder using a range of crushing strategies that were systematically evaluated for feedability and processability. The resulting powder was then blended with neat polypropylene and a masterbatch to provide the necessary functionalisation. This blend was fed directly into the hybrid injection‑moulding machine, thereby closing the material loop. A key requirement was to preserve the length of the endless fibres; the project therefore defined a specification that guided the crushing and blending process. The reference part used for the experimental validation was the door‑module carrier of the Ford Focus, a component that represents a typical automotive application. Mechanical testing of the moulded parts showed that the recycled material could be incorporated without a measurable loss of strength or stiffness, demonstrating that the closed‑loop process is viable for functional components. The project also quantified the economic and ecological benefits of incorporating a high share of production waste, showing that the approach reduces both material consumption and waste disposal.

Beyond the laboratory and pilot‑scale tests, the project produced a comprehensive closed‑loop recycling concept that can be scaled to industrial production. The results are being used as a basis for subsequent projects, notably the “Recycling material in fibre‑reinforced hybrid composites – ReProHybrid” initiative, which is currently being submitted to the German Innovation Programme for SMEs (ZIM) under the Ministry of Economic Affairs and Climate Action. Dissemination of the findings will occur through presentations at industry trade fairs such as K and Fakuma, conferences and seminars (e.g. VDI meetings, Technomer), and publications in specialist journals including “Kunststoffe”, “K‑Zeitung” and the “International Journal of Life Cycle Assessment”. The collaboration between the university and the industry partners has already led to the integration of the results into teaching and industrial training programmes, and the project has fostered further interdisciplinary cooperation between the faculties of engineering and economics at the Technical University Rosenheim.