Process for making polyethylene terephthalate
US8901271B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 17, 2010 |
| Grant date | Dec 2, 2014 |
| Priority date | — |
| Expiry date | Nov 16, 2030 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G63/85
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The invention relates to a process for making polyethylene terephthalate (PET) from ethylene glycol (EG), purified terephthalic acid (PTA) and optionally up to 6 mol % comonomer, using a mixed metal catalyst system and comprising the steps of a) esterifying EG and PTA to form diethyleneglycol terephthalate and oligomers (DGT), and b) melt-phase polycondensing DGT to form PET and EG, wherein the catalyst system substantially consists of 70-160 ppm of Sb-compound, 20-70 ppm of Zn-compound, and 0.5-20 ppm of Ti-glycolate as active components (ppm metal based on PET). With this process that applies reduced amount of metal catalyst components PET can be obtained with high productivity, which polyester shows favorable color and optical clarity, also if recycling of EG is applied within the process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.