Glycolysis of viscoelastic flexible polyurethane foam wastes

Nowadays polymer recycling processes are one of the most published research topics due to the increasing importance that is achieving the environmental world. One of most important types of polymers are the polyurethanes and among them flexible foams are the most produced ones, posing about the half of polyurethane total production. Flexible foams can be classified as conventional, viscoelastic and High Resilience (HR) ones. In recent years, viscoelastic foams have had positive recognition and acceptance from consumers and, therefore, they have seen increased their applications in the world plastic market becoming of this way the PU sector that is undergoing a faster growing. As a consequence, viscoelastic foam wastes are experimenting an exponentially growing and therefore getting a proper solution is a crucial goal. In this work, for the first time in literature, the extension of the glycolysis process to flexible viscoelastic polyurethane foams scraps has been demonstrated based on the optimized conditions determined by the research group in previous papers for conventional flexible polyurethane foam wastes and consequently a glycolyzate susceptible of being foamed in a further step has been obtained. Furthermore, it has been stated that the glycolyzate, once the purification process has taken place, is really similar to the ones achieved in the glycolysis of conventional foams and for this reason the same foaming recipe has been successfully applied. In consequence, one of the biggest challenges of the flexible PU foam glycolysis has been achieved since it has been demonstrated that the joint recycling treatment of conventional and viscoelastic PU foams blends, which mean approximately the 95% of the total flexible PU foam production, would be possible avoiding this way the necessity of a selective collection or a previous separation step of PU scraps. Furthermore, it has been stated that the glycolysis bottom phase obtained from viscoelastic flexible PU foam scraps can be used to replace partially a raw rigid polyol in the synthesis of new rigid PU foams. Hence, a global valorization of the glycolysis phases has been achieved converting them in profitable substances. (C) 2015 Elsevier Ltd. All rights reserved.