Process for the purification of polycarbonates
US4013702A · kind A · utility
14Cited by
3References
13Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 4, 1975 |
| Grant date | Mar 22, 1977 |
| Priority date | — |
| Expiry date | Dec 4, 1995 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G64/406
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The free and bonded residual phenol content of oligocarbonates prepared by transesterification between a diol and a diphenyl carbonate is substantially reduced by a process comprising (i) introducing water into the oligocarbonate in the liquid state at an elevated temperature under reduced pressure and (ii) purging the mixture with an inert gas to effect degassing. The purified oligocarbonates are particularly resistant to yellowing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.