Recycling of Microcellular Polyurethane Elastomer Waste

Abstract

Waste and scraps from polyurethane rigid foams, with a glycolysis process, can be transformed into products that are liquid at room temperature and terminated with hydrogen active groups, so that they can be directly recycled in the production process of new rigid foams. The process is a very con venient solution to an ecological problem. With proper variations the process can be applied to the recycling of polyurethane structural foams and of microcellular elastomers. The glycolysis chemistry is very complicated because of the presence in the polymer of numer ous groups taking part in the reactions, and because at the process tempera ture, secondary reactions of pyrolysis products cannot be excluded. Moreover, these reaction products can react with themselves and with the glycolysis products. It is therefore of paramount importance that the selective catalysts for the transesterification reactions be active at the lowest possible tempera tures. Chemical plants which are easily managed and require small invest ments have been built in situ by the industries that produce the waste and scraps that are available in the appropriate form and free from transport costs.