A process for incorporating automotive shredder residue into thermoplastic mouldings

This paper describes a process for utilising the waste that remains when all of the economically reclaimable materials have been recovered from automobiles that have reached the end of their lives. This waste material, known as automotive shredder residue (ASR), is currently disposed of in landfill sites but forthcoming environmental legislation in the European Union and elsewhere will drastically restrict the amount that can be disposed of in this way. By 2015, 80% of the ASR currently going to landfill must be recycled. The dual injection moulding process is used to mould a skin of virgin polymer over a compound containing the ASR which forms the core of a new component. Polypropylene (PP) was used as the skin material and also as the material to compound with the ASR. A 50%/50% mix by volume of PP and ASR granules was found to produce good results as the core material. Experiments were performed to vary the skin to core ratio in order to establish the effect of varying the proportion of ASR on the mechanical proper-ties of mouldings. It was found that mouldings produced containing 25% by volume of ASR were visually excellent due to the pure PP skin. Inclusion of higher proportions of ASR by decreasing the skin:core thickness ratio was found to produce "breakthrough" of the ASR particles into the skin and test results were highly inconsistent. Using smaller proportions of ASR can be predicted to produce better mechanical properties but would have been contrary to the aim of developing a process capable of disposing of large quantities of ASR. It is concluded that recycling of ASR by using it as a core material in the dual injection moulding process is a feasible option for mouldings requiring good visual appearance but is not suited to components requiring significant strength. (C) 2003 Elsevier Science B.V. All rights reserved