Process for the purification of high molecular weight polyesters
US4591629A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 21, 1983 |
| Grant date | May 27, 1986 |
| Priority date | — |
| Expiry date | Apr 21, 2003 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G63/90
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A method for reducing the volatile component content of crude high molecular weight polyesters containing said component. The method comprises first contacting the crude polyester with steam, or a mixture of steam and inert gas and/or air, at a temperature of 100.degree. to 245.degree. C. to form a partially treated polyester. The second step comprises further contacting the product of the first step with an inert gas and/or air at a temperature of 200.degree. to 245.degree. C. to produce the purified polyester. In particular, the method is intended for use with such polyesters as polyethylene terephthalate which contains acetaldehyde as the undesired volatile component. A new method of analysis useful in the foregoing process is also disclosed. The products of the new process are primarily intended for use in the manufacture of plastic bottles or similar containers for use in the foodstuffs industry.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.