Copolyamide acid and copolyimide
US4438256A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 6, 1983 |
| Grant date | Mar 20, 1984 |
| Priority date | — |
| Expiry date | Apr 6, 2003 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G73/1067
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A copolyamide acid comprising repeating units represented by the general formulas: ##STR1## in which the repeating unit (A) and the repeating unit (B) are present in a molar ratio from 20:80 to 80:20, and which has a logarithmic viscosity number (.eta..sub.inh) of 0.5 dl/g--10 dl/g measured in N,N-dimethylformamide at a concentration of 0.5 g/dl and at a temperature of 30.degree. C. and a copolyimide comprising repeating units represented by the general formulas: ##STR2## in which the repeating unit (C) and the repeating unit (D) are present in a molar ratio from 20:80 to 80:20 and which has a logarithmic viscosity number (.eta..sub.inh) of o.5 dl/g--10 dl/g measured in 97% concentrated sulfuric acid at a concentration of 0.5 g/dl and at a temperature of 30.degree. C.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.