Modified polymeric aromatic isocyanates having allophanate linkages
US5902840A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 7, 1996 |
| Grant date | May 11, 1999 |
| Priority date | — |
| Expiry date | Nov 7, 2016 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB22C1/2273
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The invention relates to modified polymeric aromatic isocyanates having allophanate linkages prepared by (a) reacting a polymeric aromatic isocyanate with a monofunctional aliphatic alcohol to form an intermediate modified polymeric isocyanate; and (b) reacting the intermediate modified polymeric isocyanate at an elevated temperature in the presence of a divalent metal catalyst. The invention also relates to foundry binder systems which use these modified polyisocyanates. These modified polyisocyanates, along with a phenolic resole resin, are added to a foundry aggregate to form a foundry mix which is shaped and cured with a gaseous amine curing catalyst by the cold-box process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.