Method for the preparation of microcapsules
US4938900A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 28, 1988 |
| Grant date | Jul 3, 1990 |
| Priority date | — |
| Expiry date | Mar 28, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2985
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Microcapsules are prepared by adding a methylolated melamine or methylolated urea to an aqueous emulsion of the core material dispersed in an aqueous solution of a styrene/maleic anhydride copolymer partially hydrolyzed in an alkaline condition and heating the mixture at 40.degree. to 90.degree. C. in an acidic condition so that a reaction product forming the capsule walls is produced by the esterification reaction between the carboxyl groups in the partial hydrolysis product and the methylol groups in the methylolated melamine or urea and the amidation reaction between the carboxylic anhydride groups in the former and the amino groups in the latter. By virtue of the three dimensional network structure, the capsule walls are very dense and highly resistant against heat, water and solvents.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.