Patent ID: 7803422

Claim:
A process for preparing microcapsules encapsulating a water phase, the process comprising: dispersing an oil soluble amine modified polyfunctional polyvinyl monomer or oligomer and an oil soluble bi- or polyfunctional vinyl monomer or oligomer along with a free radical initiator and an organic acid into an excess of an oil phase which is a nonsolvent for the water phase; the organic acid selected from the group consisting of monoalkyl maleate, alkyl benzene sulfonic acid, and alkyldiphenyloxide sulfonic acid; a first heating step comprising, heating for a time and temperature sufficient to oligomerize or further oligomerize the amine modified polyfunctional polyvinyl monomer or oligomer and oil soluble bi- or polyfunctional vinyl monomer oligomer forming a pre-polymer; adding to the oil phase a water phase comprising a dispersion in water of an anionic emulsifier and a free radical initiator and a core material, and emulsifying the water phase into the oil phase forming droplets of the water phase dispersed in the oil phase; a second heating step comprising, heating for a time and temperature sufficient to decompose the free radical initiators in the oil and water phases; thereby forming microcapsule wall material at the interface of the water and oil phases, the microcapsules encapsulating the water phase droplets; and a third heating step comprising heating to a temperature equal to or greater than the second heating step temperature for a time sufficient to polymerize the wall material.