Process for crystallizing polyethylene naphthalate copolymers in the absence of devolatilization
US6124423A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 24, 1999 |
| Grant date | Sep 26, 2000 |
| Priority date | — |
| Expiry date | Jun 24, 2019 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G63/80
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A process for crystallizing a polyethylene naphthalate copolymer by: PA1 a) copolymerizing at least 60 mole % of 2,6-naphthalene dicarboxylic acid, based on the total moles of carboxylic acids, with polyols such as at least 80 mole % of ethylene glycol and from 2 mole % to 20 mole % of a polyol having three or more carbon atoms, each based on the total moles of polyols, to form PEN copolymer solids, and PA1 b) subsequently crystallizing the PEN copolymer solids by heating the solids to at least their sticking temperature at an average rate of at least 10.degree. C./min, to form agglomerate-free crystallized solids. The process may be performed under agitation. The pellets heated up in a during the crystallization step do not agglomerate or suddenly expand as the temperature rises to and through the sticking temperature of the PEN copolymers. The process allows one to rapidly heat up PEN during crystallization, and do so without conducting a prior drying step or a devolitilization step.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.