Microencapsulation process and resulting microcapsules
US4269729A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 23, 1979 |
| Grant date | May 26, 1981 |
| Priority date | — |
| Expiry date | Jul 23, 1999 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2989
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Microcapsules having walls formed from polyvinyl alcohol are prepared by dispersing a substantially water insoluble nuclear material in an aqueous solution of a polyvinyl alcohol polymer, which solution has a cloud point, phase separating and depositing a concentrated aqueous solution of the polyvinyl alcohol polymer as a separated phase around said nuclear material from the bulk continuous phase by maintaining the temperature of the system above the cloud point of the aqueous polyvinyl alcohol polymer solution, and subjecting the phase separated solution to conditions which substantially solidify or gel said polyvinyl alcohol polymer in said concentrated aqueous solution of said separated phase around said nuclear material but which do not substantially solidify or gel the polyvinyl alcohol in the diluted aqueous solution of the continuous phase.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.