Liquid carbodiimide-uretonimine modified polymethylene polyphenylene polyisocyanates and polyurethane foams made therefrom
US4743626A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 14, 1987 |
| Grant date | May 10, 1988 |
| Priority date | — |
| Expiry date | Sep 14, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G18/797
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A process for the preparation of liquid polymethylene polyphenylene polyisocyanate blends containing carbodiimide-uretonimine isocyanate linkages, containing a high two-ring methylene bis(phenylisocyanate) content, and light colored polyurethane foams made therefrom. The process is comprised of reacting polymethylene polyphenylene polyisocyanate with a catalytically effective amount of a carbodiimide-uretonimine promoting compound at a temperature sufficient to promote the formation of carbodiimide-uretonimine linkages and an isocyanate content of about 25 percent and the desired viscosity is reached, and then reacting that product to deactivate the carbodiimide-uretonimine catalyst, and finally blending two ring methylene bis(phenylisocyanate) with the product to produce a mixture having a two ring isocyanate content of about 60 percent of the total ring content and a viscosity comparable to standard polymeric MDI. Urethane foams made from this material are lighter in color than those formed from standard polymeric MDI.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.