Controlled release dual walled microcapsules
AssigneeEncapsys, LLC
InventorsLinsheng Feng, Robert Stanley Bobnock
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Abstract
A method of forming dual melamine/acrylic walled microcapsules having improved physical properties and release control as well as the microcapsules formed by the process wherein the capsule wall is formed by the use of select (meth)acrylate monomers and/or oligomers and/or select self-condensing melamine resins.
Claims18
A method of making microcapsules whose shell wall comprises on one surface a melamine resin and on its other surface a (meth)acrylate polymer, said melamine resin derived from an aqueous phase composition and said (meth)acrylic polymer comprising the reaction product of either (A) a combination of (a) at least one oil soluble or dispersible amine (meth)acrylate, (b) at least one oil soluble or dispersible acidic (meth)acrylate or at least one oil soluble or dispersible simple acid or both, and (c) at least one oil soluble or dispersible multifunctional (meth)acrylate monomer or oligomer or (B) a combination of (a) at least one oil soluble or dispersible acidic (meth)acrylate, (b) at least one oil soluble or dispersible simple base, and (c) at least one oil soluble or dispersible multifunctional (meth)acrylate monomer or oligomer derived from an oil phase composition, and an intermediate region comprising an interpenetrating network and/or copolymer of melamine resin and (meth)acrylate polymer, said method comprising:
- (i) forming an oil-in-water or a water-in-oil emulsion of the melamine based aqueous phase and the (meth)acrylate ester oil phase,
- (ii) subjecting the emulsion to conditions for concurrently, at last in part, polymerizing the wall forming materials of each of the oil phase and water phase, and
- (iii) allowing the reaction to continue until the microcapsules of desired wall thickness are attained.
Dependencies are inferred from the claim text.