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Process for Preparation of Microcapsules

IP.com Disclosure Number: IPCOM000095511D
Original Publication Date: 1964-Feb-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Reyes, Z: AUTHOR

Abstract

Microcapsules are prepared (1) by dissolving a polymer in a solvent in which the polymer is relatively soluble at higher temperatures and relatively insoluble at lower temperatures; (2) forming an emulsion of the heated solution with the fluid to be encapsulated as the dispersed phase; and (3) very slowly cooling the emulsion to precipitate the polymer from the continuous phase around the dispersed phase.

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Process for Preparation of Microcapsules

Microcapsules are prepared (1) by dissolving a polymer in a solvent in which the polymer is relatively soluble at higher temperatures and relatively insoluble at lower temperatures; (2) forming an emulsion of the heated solution with the fluid to be encapsulated as the dispersed phase; and (3) very slowly cooling the emulsion to precipitate the polymer from the continuous phase around the dispersed phase.

The procedure provides a successful method for preparation of microcapsules from chemically inert polymers, such as polyethylene, polypropylene, and TEFLON* capsules. An example of the process is as follows: Solutions are prepared comprising the following ingredients: I. 20 g of POLYETHYLENE 629** 1 g of PETRONAUBA H** wax 80 g of toluene at 100 degrees C. II. 1.6 of sodium silicate 38.4 of water (30 mg of sodium alginate could be included).

Solution II is emulsified in solution I at 70 degrees C. in a three-necked flask fitted with an efficient stirrer and reflux condenser. The particle size of the internal phase of the resulting emulsion ranges from 2 to 30 microns. Stirring is continued while the emulsion is cooled gradually to room temperature. During this time, the particle size of the emulsion becomes more uniform and the polyethylene is gradually precipitated at the water-oil interphase. The emulsion is further cooled to 5 degrees C. and is stored in a refrigerator overnight. The dispersion obtained can then be fil...