CHEMICAL RECYCLING OF REINFORCED POLYURETHANE FROM THE AUTOMOTIVE INDUSTRY

R-RIM PU (reinforced-reaction injection molding polyurethanes) from th e automotive industry (production scrap and parts at the end of their life cycle) can be recycled for the production of new RIM PU by a chem ical process. Among the various possible chemical processes (hydrolysi s, alcoholysis, aminolysis, and pyrolysis), we have examined glycolysi s. a particular form of alcoholysis, for the purpose of obtaining a mi xture of oligomers sufficiently similar to a polyol to be used in the production of new R-RIM PU. Glycolysis with dipropylene glycol (DPG) o f R-RIM PU forms a monophasic product that could be used in the prepar ation of new, highly crosslinked polymers, similar to those used in th e preparation of rigid thermal insulation foams. The same product, bec ause of its high hydroxyl number, cannot be directly re-used in the pr oduction of new RIM PU. Partial substitution of free DPG in the glycol ysis product with a triol having high molecular weight forms a homogen eous mixture suitable for production of new RIM PU. This final product has been used in the original R-RIM application introducing an approp riate optimization of formulation. In comparison with RIM FU obtained from only virgin materials, the loss in properties of molded parts bas ed on even high amounts of regenerated polyol was only marginal.