Patent ID: 7985445

Claim:
A process for preparing microcapsules encapsulating a water phase, the process comprising: dispersing an oil soluble amine modified ethoxylated trimethylol propane triacrylate and an oil soluble diethylene glycol dimethacrylate along with free radical initiator and an organic acid into 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 alkyldiphenoxide sulfonic acid; a first heating step comprising, heating for time and temperature sufficient to oligomerize the amine modified ethoxylated trimethylol propane triacrylate and a diethylene glycol dimethacrylate forming a pre-polymer; adding to the oil phase a water phase comprising a dispersion in water of a polyacrylic or polymethacrylic acid, a core material, and an emulsifying agent; 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 at least a portion of the free radical initiator in the oil phase; 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 at least 90° C. for at least three hours to polymerize the wall material.