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 polyisocyanate, 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 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 cross-linking agent contains a branched polyethylenimine at a level of 0.1% to 5%, the polyisocyanate is a trimethylol propane-adduct of toluene diisocyanate, and a trimethylol propane-adduct of xylylene diisocyanate, or a combination of thereof and is present at a level of 0.1% to 10%, the oil core contains a fragrance at a level of 0.5% to 80%, 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 200 to 2,000,000 Da.
3. The polyurea capsule composition of claim 1 , wherein the capsule formation aid is (i) a mixture of carboxymethyl cellulose and polystyrene sulfonate, or (ii) a mixture of carboxymethyl cellulose and polyvinylpyrrolidone, carboxymethyl cellulose is present at a level of 0.1% to 5%, sulfonated polystyrene when present is at a level of 0.1% to 5%, and polyvinylpyrrolidone when present is at a level of 0.1% to 5%.
4. The polyurea capsule composition of claim 1 , wherein the oil core further contains a malodor counteracting agent or a core modifier.
5. The polyurea capsule composition of claim 1 , further comprising a deposition aid that is an anionic, cationic, nonionic, or zwitterionic polymer.
6. 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 a trimethylol propane-adduct of toluene diisocyanate, a trimethylol propane-adduct of xylylene diisocyanate, or a combination thereof and is present at a level of 0.1 to 10%; the oil core contains a fragrance at a level of 0.5 to 80%; and the cross-linking agent contains a branched polyethylenimine at a level of 0.1 to 5%; the capsule formation aid is (i) a mixture of carboxymethyl cellulose and sulfonated polystyrene or (ii) a mixture of carboxymethyl cellulose and polyvinylpyrrolidone; carboxyrnethyl cellulose is present at a level of 0.1% to 5%; sultonated polystyrene when used is present at a level of 0.1% to 5%, polyvinylpyrrolidone when used is present at a level of 0.1% to 5%; and all percentages are based on the weight of the polyurea capsule composition.
7. The method of claim 6 , further comprising adding a base or a catalyst into the active emulsion, wherein the base is a metal carbonate, metal bicarbonate, metal hydroxide, or combination thereof; and the catalyst is capable of increasing the rate of the reaction between the polyisocyanate and the cross-linking agent.
8. The method of claim 6 , wherein the capsule slurry is cured at 55° C. to 135° C.
9. The method of claim 6 , further comprising purifying the cured capsule slurry by diafiltration, centrifugation, or washing with water until a neutral pH is achieved.
10. The method of claim 9 , further comprising adding a salt to the cured capsule slurry before washing the capsule slurry with water.
11. A polyurea capsule composition prepared by the method of claim 6 .
12. A consumer product comprising the capsule composition of claim 1 .
13. A consumer product comprising the capsule composition of claim 11 .
14. The consumer product of claim 12 , 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.