Poly(ethylene terephthalate) waste was glycolized with diethylene glycol, optionally with trimethylolpropane, at 220 degrees C to resp. polyesterol. The product was reacted with diphenylmethane 4,4-diisocyanate in presence of foaming agents (water, pentane) and catalyst to produce polyurethane resin for adhesives (steel sheet-expanded polystyrene system). The polyesterols were also used for plastification of com. epoxy resins, optionally in presence of a vegetable oil. The plastics produced showed good mech. properties.