Microencapsulation process
US4956129A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 1, 1988 |
| Grant date | Sep 11, 1990 |
| Priority date | — |
| Expiry date | Feb 1, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2985
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A process is disclosed for the microencapsulation of a substantially water-insoluble liquid material within a porous shell to effect a slow rate of release of said material through said shell which comprises (a) providing an organic solution comprising said material and an etherified urea-formaldehyde prepolymer dissolved therein which from about 50% to about 98% of the methylol groups of said prepolymer have been etherified with a C.sub.4 -C.sub.10 alcohol; (b) creating an emulsion of said organic solution in an continuous phase aqueous solution comprising water and a surfaceactive agent, wherein said emulsion comprises discrete droplets of said organic solution dispersed in said continuous phase aqueous solution, there being formed thereby an interface between the discrete droplets of organic solution and the surrounding continuous phase aqueous solution; and (c) causing in situ self-condensation and curing of said ureaformaldehyde prepolymers in the organic phase of said discrete droplets adjacent to said interface by simultaneously heating said emulsion to a temperature between about 20.degree. C. to about 100.degree. C., and adding to said emulsion an acidifying agent and main…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.