Exterior components based on renewable resources produced with SMC technology—Considering a bus component as example

The importance of renewable resources in technical applications has increased. Within the framework of the studies, a bus body component based on natural fibres and PTP®, a vegetable based thermoset resin, is produced with the sheet-moulding-compound technology (SMC). Hitherto, the conventional component was produced of glass fibre reinforced polyester resin. The mid-term results of the studies show that it is possible to optimise the production of this textile semi-finished part by selecting qualified hemp fibres and developing a technically matured PTP®-SMC variant in such a way that the component production process based on the semi-finished parts need not be changed. All in all, it was possible to produce a homogeneous body part with the hemp/PTP®-prepreg due to the flow ability that was achieved for the natural fibres. The technical feasibility of producing an SMC-component based on renewable resources was demonstrated. The properties of the component, e.g. tensile strength, burning behaviour and water absorption, are shown and compared to the results of the series component. An assessment of the component from the end-user perspective is presented. According to the End-of-Life Vehicles Regulation, there is no advantage in components based on renewable resources over components based on petrochemical resources. However, the application of renewable resources has advantages in terms of recycling technologies, which are accepted for SMC and which will become economically more important in the future. In comparison with the polyester system, the life-cycle assessment of the polymer material PTP® shows lower values in nearly all impact categories.