Process for the preparation of semiordered polyamides-imides
US5118778A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 10, 1991 |
| Grant date | Jun 2, 1992 |
| Priority date | — |
| Expiry date | May 10, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G18/345
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The present invention relates to a process for obtaining semiordered polyamides-imides. More particularly it consists in performing the polycondensation in two separate stages: PA0 1) reaction between a part of an aromatic diisocyanate and all of the trimellitic anhydride in the presence of dimethylalkyleneurea of pH.ltoreq.7 until the intermediate compound has dissolved, PA0 2) successive addition of one or more aromatic diacids and of the remainder of the diisocyanate in the dimethylalkyleneurea of pH.ltoreq.7 until the polyamide-imide obtained has dissolved completely. The semiordered polymers thus obtained have a Tg lower than the random polymers, and this makes them easier to convert.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.