Process for preparing microcapsules having gelatin walls crosslinked with quinone

Claim 1

A process for preparing a microcapsule comprising the steps of: a) emulsifying a core material in an aqueous solution of gelatin at a temperature of about 40° C. to about 50° C. so as to produce particles having a diameter of about 30 to about 100 microns, said aqueous solution of gelatin comprising an acid precursor gelatin having a bloom strength between about 160 and about 280 and distilled water, b) adding an aqueous polyanion solution comprising distilled water and a polyanion to the emulsion, c) adding a pH adjusting agent selected from the group consisting of acetic acid, sodium hydroxide and a mixture of the two so as to adjust the pH of the emulsion to between about 4 and about 5 so as to allow coacervation, d) cooling the coacervate to room temperature at a rate of about 1° C. every 10 minutes so as to allow the coacervate to gel around the core material forming microcapsules with a wall comprising gelatin, e) rinsing said microcapsules with distilled water to remove excess coacervate, f) cooling said microcapsules for at least about 30 minutes at about 5° C. to about 10° C., g) allowing said microcapsules to come to room temperature, and h) crosslinking said wall with a saturated quinone solution for about 18 to about 36 hours at room temperature.