Color reduction of polymeric isocyanates via multiple solvent fractionation
US4876380A · kind A · utility
6Cited by
6References
16Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1988 |
| Grant date | Oct 24, 1989 |
| Priority date | — |
| Expiry date | Aug 31, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C263/20
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Disclosed is an extraction process wherein a crude polyisocyanate is separated into a purified fraction and residual fraction wherein the purified fraction is characterized by greatly improved color over the crude material but with little or no difference in viscosity. The residual fraction remains perfectly useful for those applications where color is not a critical requirement. Significantly, the disclosed purification is achieved with literally a 100 percent material balance. No loss in polyisocyanate is encountered.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.