Soy Extender Oils in Automotive Rubber: Case Studies of Natural Rubber and EPDM

Research and development of renewable or recycled materials provides an opportunity to support Ford’s corporate environmental strategy. Within elastomer components, one opportunity for using these sustainable materials is incorporation of soybean oil as a replacement for petroleum based oils in formulations. Technical case studies were conducted using degummed and modified soy oils in two different rubber matrices, Natural Rubber (NR) and Ethylene Propylene Diene Monomer (EPDM) rubber. Soy oil was incorporated at various loading levels ranging from 5-20 wt% replacement of petroleum oil in EPDM and 20-100 wt% in NR model compound formulations.  Key physical and rheological properties of these rubber compounds using renewable extender oils were assessed, including cure kinetics, tensile properties, durometer and tear resistance.  Selected formulations were evaluated for lab scale testing and prototype part trial evaluations in an exterior automotive application.  The primary technical challenges and outlook for using renewable oils in automotive rubber compounds are also discussed.

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