METHOD FOR DEPOLYMERIZING POLYETHYLENE TEREPHTHALATE

摘要

PROBLEM TO BE SOLVED: To depolymerize a polyethylene terephthalate to be recycled within a short time. SOLUTION: In producing an unsaturated polyester resin by using a polyethylene terephthalate to be recycled after it is molten by heating, the heating, melting, and depolymerization of the polyethylene terephthalate are practiced at a time by using one or more extruders or by using an extruder and a reactor provided at the exit of the extruder.