Process for preparation of polyethylene terephthalate modified by o-phthalic acid units
US6515080B1 · kind B1 · utility
1Cited by
6References
3Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Feb 5, 2002 |
| Grant date | Feb 4, 2003 |
| Priority date | — |
| Expiry date | Mar 21, 2023 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G63/78
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The invention relates to a process to produce polyethylene terephthalate modified with o-phthalic acid units while avoiding any high phthalic acid losses during esterification or polycondensation and while maintaining the favorable use properties effected by the phthalic acid.According to the present invention, a precondensate made of phthalic anhydride and ethylene glycol in a non-catalytic reaction is added in the esterification and/or polycondensation stages, whereby the ethylene glycol is used at a molar excess of 2 to 3.5 relative to the phthalic anhydride.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.