Purification/isolation of isocyanate condensates
US4871828A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 26, 1988 |
| Grant date | Oct 3, 1989 |
| Priority date | — |
| Expiry date | Sep 26, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P20/54
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Polyisocyanates containing only trace amounts of free aromatic diisocyanates are recovered by purifying and isolating an isocyanate condensate containing free NCO groups from an impure admixture thereof, said isocyanate condensate impure admixture having been prepared by reacting a stoichiometric excess of an aromatic di- or polyisocyanate with a reactant compound containing at least two functional groups which are reactive with NCO groups, and such purification/isolation entailing extracting unreacted excess di- or polyisocyanate from said impure admixture with an inert gas, e.g., carbon dioxide, in either the liquid or supercritical state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.