Controlled release dual walled microcapsules

Patent metadata

Field	Value
Publication number	US-2019282989-A1
Application number	US-201916378648-A
Country	US
Kind code	A1
Filing date	Apr 9, 2019
Priority date	Oct 16, 2014
Publication date	Sep 19, 2019
Grant date	—

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.

First claim

1 . Microcapsules whose shell wall comprises at one surface a melamine resin, at its other surface a (meth)acrylate polymer, and between the two surfaces an intermediate region comprising an interpenetrating network and/or copolymer of melamine resin and (meth)acrylate polymer, wherein the melamine resin is derived from an aqueous phase composition comprising melamine resin wall forming materials and the (meth)acrylic polymer is derived from an oil phase composition comprising (meth)acrylate polymer wall forming materials selected from (A) the 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 and/or prepolymers of two or more of the foregoing and (B) the 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 and/or prepolymers of two or more of the foregoing.

2 . The microcapsule of claim 1 wherein the microcapsule has two discrete polymer layers, a melamine layer and a (meth)acrylate polymer layer and wherein the intermediate region comprises the interface between the melamine layer and the (meth)acrylate polymer layer in which chains of the melamine resin and the (meth)acrylate polymer are intertwined with one another and/or are embedded in the other, said microcapsule wall having been formed by either (i) polymerizing the wall forming materials of one phase before polymerizing the wall forming materials of the other phase or (ii) polymerizing the wall forming materials of one phase and initiating polymerization of the wall forming materials of the other phase once polymerization of the first to be initiated wall forming material achieves the formation of a microcapsule wall through which the wall forming materials of the other phase is unable to penetrate.

3 . The microcapsules of claim 2 wherein initiation of the second to be initiated wall forming material is effected once wall forming materials of that phase is unable to penetrate the shell wall being formed but before polymerization of the first to be initiated wall forming material is completed.

4 . The microcapsule of claim 1 wherein the shell wall is wholly melamine resin at one surface and wholly (meth)acrylate polymer at the other surface and the intermediary section transitions from the wholly melamine based to the wholly (meth)acrylate polymer through the cross-section of the shell wall, said microcapsule wall having been formed by concurrently forming the capsule wall from both the aqueous phase and the oil phase, with or without a brief delay in, the initiation of polymerization of the wall forming materials of one phase relative to the initiation of polymerization of the wall forming materials of the other phase, provided that said delay, if employed, is not so long that the capsule wall being formed of the first to be initiated wall forming material is fully intact and wall forming material of the other phase is unable to penetrate through that capsule wall.

5 . The microcapsule of claim 4 wherein the polymerization of the wall forming materials in both phases is concurrent.

6 . The microcapsule of claim 4 wherein the polymerization of the wall forming materials in both phases is staggered.

7 . The microcapsule of claim 1 wherein the shell wall is wholly melamine resin on one surface and wholly (meth)acrylate polymer on the other surface and the intermediary section transitions from the wholly melamine based to the wholly (meth)acrylate polymer through the cross-section of the shell wall, said microcapsule wall having been formed by forming a seed capsule of the wall forming materials of one phase before initiating polymerization of the wall forming materials of the other phase.

8 . The microcapsules of claim 1 wherein the (meth)acrylate polymer is the reaction product of (A) (a) at least one oil soluble or dispersible amine (meth)acrylate, (b) at least one oil soluble or dispersible acidic (meth)acrylate, and (c) at least one oil soluble or dispersible multifunctional (meth)acrylate monomer or oligomer

9 . The microcapsules of claim 1 wherein the (meth)acrylate polymer is the reaction product of (A) (a) at least one oil soluble or dispersible amine (meth)acrylate, (b) at least one oil soluble or dispersible simple acid, and (c) at least one oil soluble or dispersible multifunctional (meth)acrylate monomer or oligomer.

10 . The microcapsules of claim 1 wherein the (meth)acrylate polymer is the reaction product of (A) (a) at least one oil soluble or dispersible amine (meth)acrylate, (b) the combination of at least one oil soluble or dispersible acidic (meth)acrylate and at least one oil soluble or dispersible simple acid, and (c) at least one oil soluble or dispersible multifunctional (meth)acrylate monomer or oligomer.

11 . The microcapsules of claim 1 wherein the (meth)acrylate polymer is the reaction product of (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.

12 . The microcapsules of claim 1 wherein the melamine resin is selected from a melamine-based polyurea, a melamine-formaldehyde resin, a melamine-aldehyde resin, dimethylol melamine urea, methylated dimethylol melamine urea, methylated melamine formaldehyde, methylated methylol melamine, and mixtures of melamine formaldehyde with urea formaldehyde.

13 . The microcapsules of claim 12 wherein the melamine resin is derived from monomer, oligomers and/or prepolymers of the precursors or building blocks for the melamine resin.

14 . The microcapsules of claim 1 wherein the aqueous phase composition or the oil phase composition or both have been subjected to a prepolymerization step to form prepolymers of the melamine or the (meth)acrylate, respectively, prior to initiation of the wall forming process.

15 . The microcapsules of claim 14 wherein the aqueous phase composition has been subjected to a prepolymerization step.

16 . The microcapsules of claim 14 wherein the aqueous phase composition has been subjected to a prepolymerization step.

17 . The microcapsules of claim 14 wherein both the aqueous phase composition and the oil phase composition have been subjected to a prepolymerization step.

18 . The microcapsules of claim 1 wherein the microcapsules have been formed using (meth)acrylate prepolymers.

19 . The microcapsules of claim 1 wherein the microcapsules have been formed using melamine prepolymers.

20 . The microcapsules of claim 1 wherein the shell wall of the microcapsule further comprises a polymeric emulsifier originating from the aqueous, phase which polymeric emulsifier is entrapped or encased in the shell wall material.

Assignees

• Encapsys Llc

Inventors

• Feng Linsheng
• Bobnock Robert Stanley

Classifications

• C11D17/0017

  Multi-phase liquid compositions · CPC title

• C11D3/3765

  in liquid compositions · CPC title

• A61L15/225

  Mixtures of macromolecular compounds · CPC title

• C11D17/06

  Powder; Flakes; Free-flowing mixtures; Sheets · CPC title

• B01J13/14 Primary

  Polymerisation; cross-linking · CPC title