Polyurea or polyurethane capsules
Polyurea capsule compositions. A subset of these compositions contain a plurality of capsules and a capsule formation aid, in which each of the capsules contains a polyurea wall and an oil core; the polyurea wall is formed of a reaction product of a polyisocyanate and a cross-linking agent in the presence of the capsule formation aid; and the oil core contains an active material. The polyisocyante, cross-linking agent, and capsule formation aids are described herein. Also disclosed are methods of preparing polyurea capsule compositions, as well as consumer products containing one of these compositions.
1. A method of preparing a capsule composition comprising the steps of:
(a) providing an active emulsion containing droplets of a water-immiscible phase and an aqueous phase,
(b) causing formation of capsules in the active emulsion, in the presence of (i) gum Arabic or (ii) polyvinylpyrrolidone and a copolymer of vinyl pyrrolidone and quaternized dimethylaminoethyl methacrylate, by adding a catalyst to obtain a capsule slurry; and
(c) curing the capsule slurry thereby obtaining the capsule composition,
wherein the capsule composition has capsules each containing a capsule wall and a capsule core, the capsule wall encapsulates the capsule core, the active emulsion contains a polyisocyanate and a pectin or guar gum.
2. The method of claim 1 , further comprising the step of (d) adding a deposition aid to the capsule slurry.
3. The method of claim 1 , wherein the active material is a fragrance, flavor, malodor counteracting agent, or combination thereof.
4. The method of claim 1 , wherein the polyisocyanate is an aromatic polyisocyanate, aliphatic polyisocyanate, or combination thereof; the aromatic polyisocyanate contains a phenyl moiety, a tolyl moiety, a xylyl moiety, a naphthyl moiety, a diphenyl moiety, or a combination thereof; and the aliphatic polyisocyanate is a trimer of hexamethylene diisocyanate, a trimer of isophorone diisocyanate, a biuret of hexamethylene diisocyanate, or a combination thereof.
5. The method of claim 4 , wherein the aromatic polyisocyanate is selected from the group consisting of a polyisocyanurate of toluene diisocyanate, a trimethylol propane-adduct of toluene diisocyanate, a trimethylol propane-adduct of xylylene diisocyanate, and combinations thereof; and the aliphatic polyisocyanate is based on hexamethylene diisocyanate.
6. The method for claim 1 , further comprising step (d) purifying the capsule composition by washing with water, diafiltration, or centrifugation.
7. The method of claim 1 , wherein the capsule core further contains a solvent or core modifier.
8. The method of claim 1 , wherein the active emulsion is prepared by emulsifying an oil phase into an aqueous phase, and the oil phase comprises the active material.
9. A capsule composition prepared by the method of claim 1 .
10. A consumer product comprising a capsule composition of claim 9 .