Microcapsule compositions and the method of their release

Abstract

The present invention provides microcapsules with good barrier properties and the ability to release encapsulated hydrophobic liquids at low and high pH.

Claims

1. A microcapsule composition comprising: i) a core comprising a hydrophobic liquid; and ii) a shell comprising the reaction product of at least one simple diester diacid chloride monomer and N,N,N-tris-(2-aminoethyl)-1,3,5-triazine-2,4,6-triamine.

2. The microcapsule composition of claim 1 wherein the simple diester diacid chloride monomer is pyromellitic diester diacid chloride.

3. The microcapsule composition of claim 1 wherein the hydrophobic liquid is 4,5-dichloro-2-n-octyl-3(2H)-isothiazolone.

4. The microcapsule composition of claim 1 wherein the hydrophobic liquid is a solution of dichloro-2-n-octyl-3(2H)-isothiazolone in a hydrophobic solvent.

5. A method of releasing a hydrophobic liquid wherein the method comprises placing a microcapsule composition comprising: i) a core comprising a hydrophobic liquid; and ii) a shell comprising the reaction product of at least one simple diester diacid chloride monomer and N,N,N-tris-(2-aminoethyl)-1,3,5-triazine-2,4,6-triamine into an aqueous environment having a pH of 6 or less.

6. A method of releasing a hydrophobic liquid wherein the method comprises placing a microcapsule composition comprising: iii) a core comprising a hydrophobic liquid; and iv) a shell comprising the reaction product of at least one simple diester diacid chloride monomer and N,N,N-tris-(2-aminoethyl)-1,3,5-triazine-2,4,6-triamine into an aqueous environment having a pH of 9 or greater.

Description

EXAMPLES

(1) Method of Making:

(2) The microcapsules of the present invention were prepared by interfacial polymerization based on a slight modification of procedure reported by Frechet in Broaders, K. E.; Pastine, S. J.; Grandhe, S.; Frchet, J. M. J. Chemical Communications 2011, 47, 665. A saturated solution of pyromellitic diester diacid chloride (PDDC) in toluene was emulsified with an aqueous 0.4 w/w % polyvinyl alcohol solution with magnetic stirring to produce a suspension of oil-in-water emulsion droplets, whose shapes and sizes determine the final capsule dimensions. Dropwise addition of an aqueous solution of the hydrophilic monomers, triazine and DETA initiated the polycondensation reactions at the water-oil interface to form a cross-linked polyamide shell. Maturation for 60 min afforded a suspension of microcapsules that were vacuum filtered, rinsed with DI water and acetone, and allowed to dry in air to give a white, free flowing powder.

(3) The percent of hydrophobic liquid dye solution, comprising a dye mixed with toluene, released at various points in time at low, neutral, and high pH is captured in the tables below.

(4) TABLE-US-00001 TABLE 1 1:1 Triazine:DETA - terephthaloyl chloride (TC) (Control) Time (h) pH 5 pH 7 pH 10 Toluene 2 2.65 3.06 2.74 4.86 12 0.70 1.45 0.18 4.30 24 3.66 0.16 2.23 3.56 50 5.92 0.64 3.82 4.12 72 5.33 0.32 4.63 5.81 96 6.06 0.16 5.91 5.80 120 9.45 2.25 9.44 4.12

(5) TABLE-US-00002 TABLE 2 3:1 Triazine:DETA - PDDC Time (h) pH 5 pH 7 pH 10 Toluene 3 2.80 0.27 1.88 2.42 13 10.79 3.84 8.99 1.83 24 21.44 6.92 22.85 2.56 48 39.71 14.04 60.19 2.79 72 54.58 22.35 86.51 2.08 96 64.97 31.50 96.82 2.29 120 72.11 41.60 100.35 1.39

(6) TABLE-US-00003 TABLE 3 1:1 Triazine:DETA - PDDC Time (h) pH 5 pH 7 pH 10 Toluene 3 4.76 3.96 3.66 3.29 13 26.66 1.19 30.58 3.69 24 51.46 9.79 69.54 3.83 48 83.89 35.71 97.54 4.24 72 98.41 66.52 101.38 3.27 96 101.61 90.05 100.67 3.42 120 104.43 103.27 102.45 3.41