Most of polyurethanes are thermoset that means after completion of the production reactions and when polyurethane reaches to the final properties; transformation and reformation by applying heat and increasing temperature without destruction of structure is impossible this thermal stability is due to the degree of cross-linking of polymer chain or the nature and repetition of functional group in polymeric chains. Polyurethane foams and some type of polyurethane elastomer are kinds of thermoset.
This type of polyurethanes which can be obtained from a wide range of formulation are often in the form of pellets and bullets to be used as feed for polyurethane production. Unlike the thermoset, this type of polyurethanes are able to be reshaped by applying heat at high temperature and by using injection molding and extrusion. Market demand for thermoplastic polyurethane is in shoe production industry with high performance, automotive spare part industry made by elastomers with high quality and production of pipes, hoses and electrical cables.