Polyamide-imide solutions and a process for obtaining them
US4950700A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 9, 1989 |
| Grant date | Aug 21, 1990 |
| Priority date | — |
| Expiry date | Feb 9, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2379/08
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The present invention relates to solutions of polyamide-imides which can be spun and shaped, and to a process for their preparation. They contain 5 to 30% of a polyamide-imide in a solvent mixture comprising 40-80% by weight of butyrolactone and 20-60% of an aprotic amide solvent. They are obtained by the reaction, in butyrolactone as polycondensation solvent, of a diisocyanate, an aromatic acid anhydride, optionally an alkali or alkaline-earth metal dicarboxybenzenesulfonate, and optionally another aromatic diacid, the concentration of polyamide-imide being from 15 to 36%, followed by dilution in an amide solvent, at a temperature between 120.degree. and 165.degree. C. The solutions obtained are clear at room temperature, are storable, and possess improved color.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.