Hydrolysis of polyurethane resin using a twin screw reactive extruder for recycle

A twin screw reactive extruder was applied for hydrolysis of a thermosetting polyurethane resin to improve the productivity of polyurethane recycling, The obtained hydrolysate was powder in the case of lower extrusion temperature but liquid when higher temperature was applied. The powdery hydrolysate was 140 mu m in average diameter. The liquid one consisted of two components; a liquid fraction of polyetherpolyol, whose molecular weight was nearly equal to that of the original one, and a solid fraction whose crosslink density was lower than that of the original polyurethane due to the hydrolysis of its urethane bond. These hydrolysates were added to raw materials of polyurethane resin and molded for recycling. The obtained polyurethane resin was found to show good formability and mechanical properties because added hydrolysate had low amine number, The hydrolysis of thermosetting polyurethane resin using a twin screw reactive extruder was effective for polyurethane recycling as regards productivity and mechanical properties of the recycled materials.