Method for preparing biuret-structure polyisocyanates
US4218390A · kind A · utility
Inventors
Key dates
| Filing date | May 9, 1979 |
| Grant date | Aug 19, 1980 |
| Priority date | — |
| Expiry date | May 9, 1999 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G18/7831
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A method for preparing biuret-structure polyisocyanates which comprises reacting 1,6-hexamethylenediisocyanate with water which is introduced into the reaction zone in the form of vapors in a mixture with air or an inert gas at a moisture content of said mixture of from 0.1 to 2.0 kg/kg and temperature of from 110.degree. to 130.degree. C. The reaction is carried out at a temperature ranging from 150.degree. to 170.degree. C. The polyisocyanates having biuret structure as produced by the method according to the present invention have a molecular mass of about 800, the content of isocyanate groups is as high as 23.59%. No polyurea is formed in the reaction. The process is single-staged, technologically simple and can be performed continuously.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.