Process for producing microcapsules

Patent metadata

Field	Value
Publication number	US-10195577-B2
Application number	US-201515305682-A
Country	US
Kind code	B2
Filing date	Apr 27, 2015
Priority date	Apr 29, 2014
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

A process for producing microcapsules containing a shell and a core of a liquid water-insoluble material is disclosed. The microcapsules are prepared using a bifunctional isocyanate, an anionically modified diisocyanate, a bifunctional amine, and a protective colloid. The protective colloid is a polyvinyl alcohol copolymer having hydrolysis degrees from 85 to 99.9%.

First claim

The invention claimed is:

1. A process for producing microcapsules which contain a shell and a core of a liquid water-insoluble material, comprising
(a) preparing a premix (I) from water and a protective colloid;
(b) preparing a further premix (II) from a water-insoluble liquid component and at least one bifunctional isocyanate (A) or a mixture of two or more different isocyanates containing (A) and an anionically modified diisocyanate (B) is used, wherein the anionically modified diisocyanates (B) are selected from the group which contain at least one sulfonic acid group in the molecule;
(c) mixing the two premixes (I) and (II) together until an emulsion is formed; and
(d) then pouring at least a bifunctional amine into the emulsion from step (c); and
(e) then heating the emulsion to at least 50° C. until the microcapsules are formed,
wherein the protective colloid is a polyvinyl alcohol copolymer having hydrolysis degrees from 85 to 99.9%; and
wherein the polyvinyl alcohol copolymer contains 0.1 to 30 mol % comonomers with anionic groups.

2. The process as claimed in claim 1 , wherein the polyvinyl alcohol copolymer has hydrolysis degrees between 85 to 95%.

3. The process as claimed in claim 1 , wherein the polyvinyl alcohol copolymer contains 0.1-30 mol % comonomers with sulfonic and/or carboxylate groups as anionic groups.

4. The process as claimed in claim 1 , wherein the at least one bifunctional isocyanate (A) is selected from the group consisting of hexane 1,6 diisocyanate, hexane 1,6 diisocyanate biuret, oligomers of hexane 1,6 diisocyanate, and dicyclohexanemethylene diisocyanate.

5. The process as claimed in claim 1 , wherein the weight ratio between the isocyanates (A) and (B) is in the range from 10:1 to 1:10.

6. The process as claimed in claim 1 , wherein the at least one bifunctional amine used is a polyethyleneimine.

7. The process as claimed in claim 1 , wherein the core-shell ratio (w/w) of the microcapsules is 20:1 to 1:10.

8. The process as claim in claim 3 wherein the polyvinyl alcohol contains 0.1 to 15 mol % comonomers with sulfonic and/or carboxylate groups as anionic groups.

9. The process as claim in claim 8 wherein the polyvinyl alcohol contains 0.1 to 10 mol % comonomers with sulfonic and/or carboxylate groups as anionic groups.

10. The process as claimed in claim 4 wherein the at least one bifunctional isocyanate (A) comprises a trimer of hexane 1,6 diisocyanate or dicyclohexanemethylene diisocyanate.

Assignees

• Basf Se

Inventors

• Burakowska-Meise Ewelina
• Denuell Wolfgang
• Issberner Ulrich

Classifications

• B01J13/14 Primary

  Polymerisation; cross-linking · CPC title

• A61K9/5026

  obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyvinyl pyrrolidone, poly(meth)acrylates · CPC title

• A61K9/5089

  Processes · CPC title

• A61Q19/00

  Preparations for care of the skin · CPC title

• A61K8/8129

  Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical; Compositions of hydrolysed polymers or esters of unsaturated alcohols with saturated carboxylic acids; Compositions of derivatives of such polymers, e.g. polyvinylmethylether · CPC title