Process for the production of polyamidocarboxylic acids
US3981847A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 7, 1974 |
| Grant date | Sep 21, 1976 |
| Priority date | — |
| Expiry date | Nov 7, 1994 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G73/1032
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A process for the producing a polyamidocarboxylic acid, or so-called polyamic acid, which is the prepolymer in forming a polyamide and which requires the reaction of a tetracarboxylic acid dianhydride with a diprimary diamine below about 50.degree.C. in an anhydrous, polar, aprotic organic solvent, characterized by an initial treatment of the dianhydride by only wetting with an inert organic solvent or by at least wetting this dianhydride with the polar, aprotic solvent and thereafter adding to the wetted dianhydride a solution of the diamine in the polar, aprotic solvent under thorough mixing, preferably within a very short period of time after treating the dianhydride. Stable polyamic acid solutions formed in this manner are useful intermediates in preparing films, filaments or other shaped polyimide products.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.