Wholly aromatic polyamic acid solution composition
US4535105A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 1984 |
| Grant date | Aug 13, 1985 |
| Priority date | — |
| Expiry date | Mar 7, 2004 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2379/08
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An aromatic polyamic acid solution composition useful as an electrically insulating varnish, comprises (1) an aromatic polyamic acid which is a polymerization product of (A) a tetracarboxylic acid component containing at least 80 molar % of the sum of (a) a first acid ingredient consisting of 3,3',4,4'-biphenyltetracarboxylic dianhydride and (b) a second acid ingredient consisting of at least one member selected from the group consisting of pyromellitic dianhydride, and 3,3'4,4'-benzophenone tetracarboxylic dianhydride, the molar ratio of the first acid ingredient to the second acid ingredient being in the range of from 30:70 to 75:25, with (B) an amine component consisting of at least one aromatic amine in a molar ratio of the tetracarboxylic acid component to the amine component of from 97:100 to 103:100, and which polymeric acid has a logarithmic viscosity number of from 0.1 to 1.5 determined in a concentration of 0.5 g/100 ml in N-methyl-2-pyrrolidone at a temperature of 30.degree. C., and dissolved in a concentration of from 5% to 40% by weight in (2) an organic polar solvent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.