Incorporation of finely divided additives at the surface of microcapsule walls
AssigneeEurand America, Inc.
InventorJoseph A. Scarpelli
Life of this patent
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Abstract
Microcapsules are prepared en masse which contain a substantially water-insoluble core and, incorporated at their surface under a thin film of hydrophilic polymeric colloid, a substantially water insoluble finely divided additive. In the preparation, a primary microcapsule is made in an aqueous vehicle to surround the water-insoluble core, the finely divided additive is then added under stirring to form a fine dispersion and cationic hydrophilic polymeric colloid solution is added to cause the colloid to envelop the additive and deposit it on the capsule wall under a thin film.
Claims6
A method for preparing en masse, in an aqueous manufacturing vehicle, microcapsules with a substantially water-insoluble core and containing incorporated at their surface under a thin polymer film a substantially water-insoluble finely divided additive which comprises the steps of:
- (a) producing an aqueous suspension of microcapsules containing a substantially water-insoluble core material and having as at least one wall material component an anionic hydrophilic polymeric colloid which produces a solid wall around the core,
- (b) then adding substantially water-insoluble finely divided additive under stirring to produce a fine dispersion, and
- (c) adding cationic hydrophilic polymeric colloid solution without further addition of anionic hydrophilic colloid to cause the colloid to envelop the additive and deposit it on the capsule wall under a thin film.
Dependencies are inferred from the claim text.