Process for the preparation of polyester, a polyester and its use
US5417908A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 15, 1993 |
| Grant date | May 23, 1995 |
| Priority date | — |
| Expiry date | Dec 15, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2913
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Process for making a polyester having polyethylene terephthalate units including transesterifying a terephthalic acid ester with a glycol using a manganese salt as catalyst and then subjecting the product to a polycondensation reaction using a germanium-containing catalyst to form a polyester; adding phosphorous compounds to block 80 to 99% by weight of the active manganese salt thus leaving an unblocked portion of the manganese salt prior to the polycondensation; and adding 10 to 100 ppm of Ge at the end of a ethylene glycol stage of the polymerization so that the Ge and the unblocked portion of the manganese salts provide the germanium-containing catalyst for the polycondensation reaction. The P/Mn molar ratio being less than 1. The reaction mixture contains 10 to 100 ppm of manganese during the reaction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.