Method for preparing refined lactide from recovered polylactic acid
US9475790B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 5, 2014 |
| Grant date | Oct 25, 2016 |
| Priority date | — |
| Expiry date | Nov 5, 2034 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/62
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method for preparing lactide from recovered polylactic acid, the method including the following steps: A. pretreating the recovered polylactic acid; B. extruding the treated polylactic acid from a twin screw extruder to yield a polylactic acid melt, and introducing the polylactic acid melt to a pre-depolymerization kettle; C. carrying out a chain scission reaction to break molecular chains in the polylactic acid melt and to decrease the number-average molecular weight of the polylactic acid melt to below 5000; D. conducting depolymerization reaction to yield a crude lactide; and E. purifying the crude lactide and crystallizing the purified lactide.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.