| abstract |
(57) [Problem] To depolymerize polyethylene terephthalate to be recycled in a short time. SOLUTION: In producing an unsaturated polyester resin by using polyethylene terephthalate to be recycled by heating and melting it, using one or more extruders, or using an extruder and an outlet of this extruder Using the provided reactor, the heating, melting, and depolymerization reactions of the polyethylene terephthalate to be recycled are performed at a time. |