Capsule manufacture
US4490313A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 24, 1983 |
| Grant date | Dec 25, 1984 |
| Priority date | — |
| Expiry date | Jan 24, 2003 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2985
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A process is disclosed for performing encapsulation, en masse, by an in situ polymerization reaction to yield capsule wall material. The reaction comprises the polymerization of urea and formaldehyde, monomeric or low molecular weight polymers of dimethylol urea or methylated dimethylol urea, melamine and formaldehyde, monomeric or low molecular weight polymers of methylol melamine or methylated methylol melamine, in an aqueous vehicle and the reaction is conducted in the presence of mixtures of poly-electrolyte material, esp. poly(acrylic acid), and polystyrene sulfonic acid and/or salts thereof in certain critical proportions. The disclosed encapsulation process provides improved resistance of the emulsion of intended capsule core material to destabilization and permits the manufacture of micro-capsules with improved drop size distribution.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.