Melamine formaldehyde microencapsulation in aqueous solutions containing high concentrations of organic solvent
US5268130A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 20, 1990 |
| Grant date | Dec 7, 1993 |
| Priority date | — |
| Expiry date | Dec 20, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2985
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A process for making melamine-formaldehyde microcapsules in an aqueous solution containing a high concentration of a water miscible or water soluble organic solvent is provided. The aqueous solution is prepared and a water insoluble melamine-formaldehyde pre-condensate is dissolved therein by adjusting the temperature and organic solvent concentration of the aqueous solution such that the melamine-formaldehyde pre-condensate is barely soluble therein. A substance to be encapsulated, preferably an oily solution containing a dyestuff precursor, is dispersed into the aqueous solution to form an emulsion, the melamine-formaldehyde pre-condensate being insoluble in the substance to be encapsulated. The melamine-formaldehyde pre-condensate is separated from the aqueous solution onto droplets of the substance to be encapsulated and the self-condensation reaction of the phase-separated melamine-formaldehyde pre-condensate initiated to form capsule walls around the droplets, thereby producing melamine-formaldehyde microcapsules in the aqueous solution containing a high concentration of a water miscible or water soluble organic solvent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.