US 12,071,521 B2
Method, device and use for reprocessing substantially polyalkylene terephthalate
Carsten Eichert, Lüneburg (DE); Esther Brepohl, Lüneburg (DE); Stephan Scholl, Lüneburg (DE); and Lars Biermann, Lüneburg (DE)
Assigned to RITTEC UMWELTTECHNIK GMBH, Lüneburg (DE)
Appl. No. 17/275,822
Filed by Rittec Umwelttechnik GmbH, Lüneburg (DE)
PCT Filed Sep. 4, 2019, PCT No. PCT/EP2019/073598
§ 371(c)(1), (2) Date Mar. 12, 2021,
PCT Pub. No. WO2020/053051, PCT Pub. Date Mar. 19, 2020.
Claims priority of application No. 10 2018 122 210.6 (DE), filed on Sep. 12, 2018.
Prior Publication US 2021/0253823 A1, Aug. 19, 2021
Int. Cl. C08J 11/24 (2006.01); B29B 17/02 (2006.01); B29B 17/04 (2006.01); B29K 67/00 (2006.01)
CPC C08J 11/24 (2013.01) [B29B 17/02 (2013.01); B29B 17/0412 (2013.01); B29B 2017/0296 (2013.01); B29K 2067/003 (2013.01); C08J 2367/02 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A method for reprocessing waste products containing polyalkylene terephthalate, the method comprising the steps of:
depolymerizing the waste products in a continuous process, the continuous process being performed in a twin-screw extruder,
the depolymerizing including adding a solid alkali hydroxide and/or solid alkaline earth hydroxide to the waste products to produce a reaction mixture, the reaction mixture consisting of the waste products and the solid alkali hydroxide and/or solid alkaline earth hydroxide,
adding an alkylene glycol to the reaction mixture as a reactant, wherein the alkylene glycol is an alkylene glycol produced as a product of the depolymerizing, wherein no further reactive components are added to the reaction mixture,
wherein the twin-screw extruder is used for transporting the reaction mixture during the depolymerizing, the screws of the twin-screw extruder are co-rotating, and
the transporting of the reaction mixture includes at least one of kneading, mixing, conveying, and reverse conveying the reaction mixture by the twin-screw extruder such that an average dwell time of the reaction mixture in the twin-screw extruder of no greater than 2 minutes is achieved.