Molding compositions or masses suitable for manufacturing foundry molds and cores using the cold box method
US4076683A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 15, 1975 |
| Grant date | Feb 28, 1978 |
| Priority date | — |
| Expiry date | Aug 15, 1995 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB22C1/2273
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Molding compositions or masses comprising sand and a two-component binder system are prepared. These two-component binders consist essentially of 1) polyisocyanate and 2) a low molecular weight polymethylol produced by the controlled condensation of narrow mole ratios of acetone and formaldehyde under alkaline reaction conditions followed by acidification and removal of sufficient water to produce a minimum solid content of at least 95%. These molding compositions cure so fast that they may be taken off the mold five minutes after having been cured with an amine curing agent, and reach a substantial bending strength within minutes of curing compared to prior art compositions which achieve comparable bending strength only after a period of as long as one hour.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.