Process for producing low viscosity isocyanate trimers
US5298431A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1991 |
| Grant date | Mar 29, 1994 |
| Priority date | — |
| Expiry date | Sep 30, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D251/34
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
This invention relates to a multi-step process for isolating a cyclotrimerized isocyanate from mixture containing said cyclotrimerized isocyanate plus an isocyanate oligomer which comprises the steps of: (a) contacting said mixture with a liquid solvent to provide a solvent-containing mixture, (b) extracting said solvent-containing mixture by liquid-liquid extraction to cause said solvent-containing mixture to elute into an extractate and a residue, wherein said extractate is a cyclotrimerized isocyanate that is essentially oligomer-free and is further characterized by having reduced viscosity relative to said solvent-containing mixture, and (c) separating uncyclotrimerized monomer from said extractate to provide a reduced viscosity trimer product that is essentially free of monomer. Also disclosed is the reduced-viscosity product produced by this process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.