GLYCOLYSIS OF FLEXIBLE POLYURETHANE FOAMS

Flexible water blown polyurethanes are polymers with repeating urethan e and urea groups. When they undergo heating in the presence of glycol s the reaction of these groups leads to soluble products. The transest erification reaction of the groups, that leads to the formation of new carbamate is faster than that of the urea groups. Carbamates in turn undergo aminolysis due to the amines formed in the glycolysis of the u rea groups. The use of ethylene glycol (EG) allows the process to be c arried out with high polymer/glycol ratio (up to 4:1). A polyphase pro duct is obtained with a top liquid phase mainly formed by the polyethe r polyol from the polymer, an intermediate liquid phase formed by the solution of carbamates, ureas and amines in EG and a bottom solid phas e with compounds with prevalent urea bonds.