Process for preparing high molecular weight polyesters
US4446303A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 1983 |
| Grant date | May 1, 1984 |
| Priority date | — |
| Expiry date | Jul 26, 2003 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G63/80
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Disclosed is a process for the manufacture of high molecular weight polyesters, particularly poly(ethylene terephthalate) (PET) and modified PET, having inherent viscosities (I.V.) for example, above about 0.6, and up to about 1.3 or higher. Such polymers are useful, for example, as structural moldings, self-supporting sheets and films, and blow-molded bottles. The process involves one or more recrystallizations of the polymer incident to solid-state polycondensation, which recrystallizations, it has been discovered, restores the high polycondensation activity of the polymer experienced in the early stages thereof and allows greatly increased overall build-up rate and higher final I.V. for the total polycondensation period. The process is particularly applicable to crystallizable polyesters in general which lend to solid-state build-up.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.