US 11,926,709 B2
Method for recycling waste polyester
Huayu Fang, Shanghai (CN); Enbin Zhu, Shanghai (CN); Dubin Wang, Shanghai (CN); Guoqing Yu, Shanghai (CN); Jincheng Chen, Shanghai (CN); Tianyuan Li, Shanghai (CN); Jiantong Wu, Shanghai (CN); Jianhua Chen, Shanghai (CN); and Shengyao Lin, Shanghai (CN)
Filed by AVANTGARDE (SHANGHAI) ENVIRONMENTAL TECHNOLOGY CO., LTD., Shanghai (CN)
Filed on Sep. 7, 2020, as Appl. No. 17/013,674.
Application 17/013,674 is a continuation in part of application No. PCT/CN2020/076452, filed on Feb. 24, 2020.
Claims priority of application No. 201910617915.X (CN), filed on Jul. 10, 2019.
Prior Publication US 2021/0024718 A1, Jan. 28, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. C08J 11/22 (2006.01); C07C 67/02 (2006.01); C07C 69/82 (2006.01)
CPC C08J 11/22 (2013.01) [C07C 67/02 (2013.01); C07C 69/82 (2013.01); C08J 2367/02 (2013.01)] 11 Claims
 
1. A method for recycling waste polyester comprising:
material pretreatment: dewatering and deoxidizing waste polyester material to obtain waste polyester as raw material;
feeding in melted state: after the step of material pretreatment melting the waste polyester to obtain melted waste polyester and feeding the melted waste polyester to a alcoholysis tank, wherein before the step of feeding the melted waste polyester to the alcoholysis tank the alcoholysis agent is added in the melted waste polyester for preliminary alcoholysis and the alcoholysis agent is ethylene glycol;
alcoholysis: the melted waste polyester, an alcoholysis agent, and an alcoholysis catalyst undergo depolymerization reaction in the alcoholysis tank to obtain alcoholysis product; and
transesterification: the transesterification agent, a transesterification catalyst and the alcoholysis product undergo transesterification reaction in the transesterification tank;
wherein based on the weight of the waste polyester raw material, the dosage of the alcoholysis agent is 10 ppm-5% during the preliminary alcoholysis.