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.
Claims47
Microcapsules whose shell wall comprises both melamine resin and (meth)acrylate polymer wherein the melamine resin is derived from an aqueous phase and the (meth)acrylate polymer is derived from an oil phase, said (meth)acrylate polymer comprising the reaction product of either (A) (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) 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.
Microcapsules whose shell wall comprises both melamine resin and (meth)acrylate polymer wherein the melamine resin is derived from a first aqueous phase and the (meth)acrylate polymer is derived from a second aqueous phase, said (meth)acrylate polymer comprising the reaction product of (a) at least one water soluble or dispersible multifunctional (meth)acrylate monomer or oligomer alone or in combination with (b) at least one water soluble or dispersible mono- and/or di-functional (meth)acrylate and/or (c) at least one water soluble or dispersible simple base, wherein said shell wall is formed by the sequential polymerization of the wall forming materials of the two aqueous phases, one aqueous phase, either the first aqueous phase or the second aqueous phase, being subjected to wall forming conditions to form a first microcapsule wall before the other aqueous phase is subjected to wall forming conditions to effect deposition and polymerization of the second wall forming material upon the first microcapsule wall.
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 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.
A method of making dual melamine resin/(meth)acrylate polymer walled microcapsules from a first water phase composition comprising a melamine resin forming composition and a second water phase composition comprising a (meth)acrylate polymer forming composition wherein the method comprises:
- (i) forming an oil-in-water emulsion wherein the oil phase comprises the core material to be encapsulated and one of the first or second aqueous phase compositions,
- (ii) subjecting the oil-in-water emulsion to conditions for effecting polymerization of the wall forming material contained in the selected aqueous phase composition,
- (iii) maintaining the reaction mix under such conditions as will effect the encapsulation of the oil phase in a polymer shell formed of the wall forming composition of the selected aqueous phase composition;
- (iv) once the oil phase is fully encapsulated, adding the other aqueous phase composition to the reaction mix or isolating the microcapsules so formed and adding them to the other aqueous phase, and subjecting the so formed mixture to such conditions as will effect polymerization of the wall forming material of the subsequently added/other aqueous phase composition, and
- (v) maintaining the reaction mix under such conditions as will effect deposition and polymerization of the wall forming material of the subsequently added aqueous phase composition until the desired wall thickness is attained.
Dependencies are inferred from the claim text.