Process for recycling polyester materials
US7192988B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 2004 |
| Grant date | Mar 20, 2007 |
| Priority date | — |
| Expiry date | Jun 11, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/62
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The present invention is a process for recycling colored polyester. More specifically, colored polyester for recycling is depolymerized by the addition of glycol to form the monomer BHET. The BHET is contacted with activated carbon to remove some colorant. The remaining colorant is extracted with water, alcohol, or glycol to produce white, purified BHET. The white, purified BHET is separated from the extraction solvent (water, alcohol, or glycol) by filtering, decanting, or centrifuging, for example. The purified BHET monomer can be polymerized to polyethylene terephthalate meeting food contact specifications, using known polymerization processes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.