This paper discusses a unique process for the post consumer recycling of complex automotive parts, such as Foam Sheet Laminate (FSL) headliners and Instrument Panel (IP) supports, produced with a Styrene Maleic Anhydride (SMA) copolymer core. This new recycling method has been developed by a German engineering company, RCM GmbH. The SMA polymers described in the paper are marketed by ARCO Chemical under the tradename DYLARK Engineering Resins.
This recycling principle is based on selective solution of different polymers. The recycled polymer, which in this case is the SMA, is dissolved in a suitable solvent and the polymer is thereafter precipitated and recovered. Both solvent and precipitation agent are recovered and reused in the process. Factors contributing to the success of this process are the ability to recover the major polymer in a complex part, as for example, in an instrument panel laminate which consists of a decorative skin, a polyurethane layer and a base of glass fibre reinforced SMA. Moreover, the solvent is relatively cheap and is not regarded as an environmental hazard.
The general principle of the process is described in a case study, that is, by describing the route of the material from parts to recycled material in a 60 metric TPA pilot plant situated in Germany. The efficiency of the process is demonstrated by giving examples of parts that have successfully been moulded from a blend of the virgin/recycled material (ratio 70130 % w/w) under fully automatic production conditions and have passed without problem through post processing including assembly by vibration welding. Physical testing indicates that the physical properties of the virgin/recycle mixture lie within 10 % of the values obtained from virgin material.