Process for microencapsulation
US5164126A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 5, 1991 |
| Grant date | Nov 17, 1992 |
| Priority date | — |
| Expiry date | Mar 5, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2985
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
An improved process for producing by interfacial reaction, a high solids an aqueous slurry of microcapsules is disclosed. Typical interfacial reaction involves the steps of emulsifying an oil phase containing the material to be encapsulated plus an oil-soluble, film-forming polyisocyanate in a continuous aqueous phase containing an emulsifying polymer under high shear conditions until the desired droplet size is obtained and then, under low shear conditions, adding a polyamine solution followed by an elevated temperature reaction sufficient to complete hardening of the polyurea capsule walls. The improvement of the invention comprising the introduction of a reaction period at elevated temperature between emulsification and polyamine addition, said reaction period permitting capsules of 10 microns or less average diameter to be made at greater than 40% by weight solids without agglomeration or resultant excess viscosity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.