Process for preparing polymethylene-polyphenyl polyisocyanates
US4307029A · kind A · utility
4Cited by
6References
16Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 1, 1980 |
| Grant date | Dec 22, 1981 |
| Priority date | — |
| Expiry date | Dec 1, 2000 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G18/8064
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A process for preparing polymethylene polyphenyl polyisocyanates, in which N-phenyl carbamic acid esters are subjected to a condensation reaction with formaldehyde, and the reaction product containing polymethylene polyphenyl polycarbamic acid esters and unreacted N-phenyl carbamic acid esters is thermally decomposed to obtain polymethylene polyphenyl polyisocyanates.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.