Methods and materials for depolymerizing polyesters
US9255194B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 15, 2013 |
| Grant date | Feb 9, 2016 |
| Priority date | — |
| Expiry date | Feb 15, 2034 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/62
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Provided is a method of depolymerizing polyesters from post-consumer products, such as beverage bottles, to produce a high purity reaction product. For the depolymerization reaction, the polyesters are reacted with an alcohol and an amine organocatalyst at a temperature of about 150° C. to about 250° C. In one application, the use of an organocatalyst with a boiling point significantly lower than the boiling point of the reactant alcohol allows for the ready recycling of the amine organocatalyst. In another application, performing the depolymerization reaction under pressure at a temperature above the boiling point of the alcohol allows for accelerated depolymerization rates and the recovery of the organocatalyst with no further heat input. In a further application, glycolytic depolymerization of poly(ethylene terephthalate) (PET) produces a reaction product of bis(2-hydroxyethyl)terephthalate (BHET), which may in turn be used to produce high purity beverage bottle grade PET, in a closed loop process with minimal waste.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.