Polyurea or polyurethane capsules
Poiyurea or polyurethane 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 poiyurea or polyurethane wall and an oil core; the poiyurea or polyurethane 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 poiyurea and polyurethane capsule compositions, as well as consumer products containing one of these compositions.
1. A polyurea capsule composition comprising a plurality of capsules and a capsule formation aid, wherein 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; the polyisocyanate is present at a level of 0.1 to 10%; the oil core contains an active material at a level of 0.5 to 80%; the cross-linking agent contains a branched polyethylenimine at a level of 0.1 to 5%; the capsule formation aid is a mixture of polyvinylpyrrolidone and a copolymer of vinyl pyrrolidone and quaternized dimethylaminoethyl methacrylate; polyvinylpyrrolidone is present at a level of 0.1 to 5%; the copolymer of vinyl pyrrolidone and quaternized dimethylaminoethyl methacrylate is present at a level of 0.1 to 5%; the active material contains a fragrance; and all percentages are based on the weight of the polyurea capsule composition.
2. The polyurea capsule composition of claim 1 , wherein the branched polyethylenimine has a molecular weight of 10,000 to 2,000,000 Da.
3. The polyurea capsule composition of claim 1 , wherein the polyisocyanate is an aromatic polyisocyanate, aliphatic polyisocyanate, or combination thereof, the aromatic polyisocyanate containing a phenyl, tolyl, xylyl, naphthyl, or diphenyl moiety, or a combination thereof, and the aliphatic polyisocyanate being a trimer of hexamethylene diisocyanate, a trimer of isophorone diisocyanate, a biuret of hexamethylene diisocyanate, or a combination thereof.
4. The polyurea capsule composition of claim 3 , wherein the polyisocyanate is an aromatic polyisocyanate selected from the group consisting of a polyisocyanurate of toluene diisocyanate, a trimethylol propane-adduct of toluene diisocyanate, and a trimethylol propane-adduct of xylylene diisocyanate.
5. The polyurea capsule composition of claim 3 , wherein the polyisocyanate is an aliphatic polyisocyanate.
6. The polyurea capsule composition of claim 1 , wherein the active material further contains a flavor or a malodor counteracting agent.
7. The polyurea capsule composition of claim 1 , wherein the oil core further contains a core modifier.
8. The polyurea capsule composition of claim 1 , further comprising a deposition aid that is an anionic, cationic, nonionic, or zwitterionic polymer.
9. A method of preparing a polyurea capsule composition of claim 1 comprising:
(a) preparing an oil phase comprising an active material and a polyisocyanate;
(b) preparing a dispersant solution containing a capsule formation aid;
(c) emulsifying the oil phase into the dispersant solution to form an active emulsion;
(d) adding a cross-linking agent to the active emulsion to form a capsule slurry; and
(e) curing the capsule slurry, thereby obtaining a polyurea capsule composition,
wherein the capsule composition has a plurality of capsules and the capsule formation aid; each of the capsules contains a polyurea wall and an oil core; the polyurea wall is formed of a reaction product of the polyisocyanate and the cross-linking agent in the presence of the capsule formation aid; the polyisocyanate is present at a level of 0.1 to 10%; the oil core contains the active material at a level of 0.5 to 80%; the cross-linking agent contains a branched polyethylenimine at a level of 0.1 to 5%; the capsule formation aid is a mixture of polyvinylpyrrolidone and a copolymer of vinyl pyrrolidone and quaternized dimethylaminoethyl methacrylate; polyvinylpyrrolidone is present at a level of 0.1 to 5%; the copolymer of vinyl pyrrolidone and quaternized dimethylaminoethyl methacrylate is present at a level of 0.1 to 5%; the active material contains a fragrance; and all percentages are based on the weight of the polyurea capsule composition.
10. The method of claim 9 , further comprising adding a base into the active emulsion.
11. The method of claim 10 , wherein the base is a metal carbonate, metal bicarbonate, metal hydroxide, or combination thereof.
12. The method of claim 9 , further comprising adding a catalyst to the active emulsion, wherein the catalyst is capable of increasing the rate of the reaction between the polyisocyanate and the cross-linking agent.
13. The method of claim 9 , wherein the cross-linking agent is added to the active emulsion at 20-45° C.
14. The method of claim 9 , wherein the capsule slurry is cured at 55-135° C.
15. The method of claim 9 , further comprising purifying the cured capsule slurry by diafiltration, centrifugation, or washing with water until a neutral pH is achieved.
16. The method of claim 15 , further comprising adding a salt to the cured capsule slurry before washing the capsule slurry with water.
17. A polyurea capsule composition prepared by the method of claim 9 .
18. A consumer product comprising the capsule composition of claim 1 .
19. The consumer product of claim 18 , wherein the consumer product is a shampoo, a hair conditioner, a soap, a body wash, a cosmetic preparation, a body liquid detergent, an all-purpose cleaner, a fabric softener or refresher, an ironing water, a fabric detergent, a softener, a drier sheet, a fine fragrance, an Eau De Toilette product, a deodorant, an roll-on product, or an aerosol product.