Convective leaching of polybenzazole films
US5292470A · kind A · utility
3Cited by
14References
19Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 5, 1993 |
| Grant date | Mar 8, 1994 |
| Priority date | — |
| Expiry date | Jan 5, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2379/06
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Films made from polybenzazole dopes can quickly be leached to remove polyphosphoric acid and other residual solvents by passing a leaching fluid such as steam through pores in the wet, never dried film. The process can reach acceptable residual phosphorous levels (1500-2000 ppm) in as little as about 2 or 3 minutes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.