IMPROVEMENTS IN OR RELATING TO ORGANIC COMPOUNDS

Abstract

Described are encapsulated compositions comprising at least one core-shell microcapsule. The at least one core-shell microcapsule comprises a core comprising at least one benefit agent and a shell surrounding the core. The shell comprises a polyurea resin formed by reaction of at least one trifunctional isocyanate with at least one polyfunctional amine not being chitosan. The at least one trifunctional isocyanate is an adduct of an aliphatic triol with at least one araliphatic diisocyanate. The weight ratio between moieties of the polyurea resin, which are derived from the trifunctional isocyanate, and the core is between 0.09 and 0.30, preferably between 0.10 and 0.20, more preferably between 0.11 and 0.18. The shell additionally comprises chitosan. The present disclosure also relates to a method for preparing such encapsulated compositions and to their use to enhance the performance of a benefit agent in a consumer product.

Claims

1. An encapsulated composition comprising at least one core-shell microcapsule, wherein the at least one core-shell microcapsule comprises a core comprising at least one benefit agent and a shell surrounding the core, wherein the shell comprises a polyurea resin formed by reaction of at least one trifunctional isocyanate with at least one polyfunctional amine not being chitosan, wherein the at least one trifunctional isocyanate is an adduct of an aliphatic triol with at least one araliphatic diisocyanate, wherein the weight ratio between moieties of the polyurea resin, which are derived from the trifunctional isocyanate, and the core is between 0.09 and 0.30, and wherein the shell additionally comprises chitosan.

2. The composition according to claim 1, wherein the aliphatic triol is selected from the group consisting of 2-ethylpropane-1,2,3-triol and 2-ethyl-2-(hydroxymethyl)propane-1,3-diol.

3. The composition according to claim 1, wherein the at least one araliphatic diisocyanate is selected from the group consisting of 1,2-bis(isocyanatomethyl)benzene, 1,3-bis(isocyanatomethyl)benzene, 1,4-bis(isocyanatomethyl)benzene, 1-isocyanato-2-(isocyanatomethyl)benzene, 1-isocyanato-3-(isocyanatomethyl)benzene and 1-isocyanato-4-(isocyanatomethyl)benzene.

4. The composition according to claim 1, wherein the at least one trifunctional isocyanate is an adduct of 2-ethylpropane-1,2,3-triol and 1,3-bis(isocyanatomethyl)benzene.

5. The composition according to claim 1, wherein the chitosan is deposited on an outer surface of the shell surrounding the core and/or the chitosan is entrapped in the shell surrounding the core.

6. The composition according to claim 5, additionally comprising free chitosan.

7. The composition according to claim 1, wherein the polyurea resin is formed by reaction of the at least one trifunctional isocyanate with the at least one polyfunctional amine not being chitosan and with the chitosan.

8. The composition according to claim 1, wherein the polyurea resin is formed by reaction of the at least one trifunctional isocyanate and a water-dispersible polyisocyanate with the at least one polyfunctional amine not being chitosan, and optionally with the chitosan.

9. The composition of according to claim 1, wherein the water-dispersible polyisocyanate is a water-dispersible polyisocyanate based on hexamethylene diisocyanate.

10. The composition according to claim 1, wherein the polyfunctional amine not being chitosan is a poly(ethyleneimine).

11. The composition according to claim 1, wherein shell additionally comprises a cationic polymer.

12. The composition according to claim 1, wherein the weight ratio between the chitosan and/or moieties of the polyurea resin, which are derived from the chitosan, and the core is between 0.002 and 0.01.

13. The composition according to claim 1, wherein the chitosan has an average molecular weight of from 5,000 to 1,000,000 g/mol, preferably from 7,500 to 500,000 g/mol, still more preferably from 10,000 to 250,000 g/mol.

14. The composition according to claim 1, wherein the chitosan has an average deacetylation grade of higher than 60%.

15. The composition according to claim 1, wherein the benefit agent is selected from the group consisting of at least one perfume ingredient and at least one cosmetic ingredient.

16. A method of preparing an encapsulated composition, the method comprising the steps of: a) Providing a core composition comprising at least one trifunctional isocyanate, optionally a water dispersible polyisocyanate, and at least one benefit agent; b) Mixing the core composition with water and optionally a cationic copolymer; c) Emulsifying the mixture obtained in b) in order to obtain core composition droplets having a volume average size of 1 to 100 μm; d) Adding at least one polyfunctional amine not being chitosan, preferably while keeping the mixture obtained in c) under stirring; e) Heating progressively the mixture obtained in d) to a temperature of from 60 to 95° C.; f) Adding chitosan to the mixture obtained in step e), and preferably maintaining the mixture at the temperature applied in step e), over a period of time from 1 to 5 hours; g) Letting the mixture obtained in f) cool down to room temperature, in order to obtain a slurry of microcapsules, wherein the weight of the trifunctional isocyanate used in step a) in relation to the weight of the core composition provided in step a) is between 8 and 20 wt. %.

17. The method according to claim 16, wherein the mixture formed in step b) is allowed to stand without stirring until the core composition and the water phase separate.

18. An encapsulated composition obtained by the method of claim 16.

19. A method of enhancing the performance of a benefit agent in a consumer product, the method comprising the step of: including the encapsulated composition within the composition of the consumer product.

20. A consumer product comprising an encapsulated composition according to claim 1.

21. The consumer product of claim 21, wherein the consumer product is a hair care product.

Description

EXAMPLE 1—PREPARATION OF POLYUREA MICROCAPSULES ACCORDING TO THE PRESENT INVENTION

[0109] In Example 1.1, the microcapsules have been obtained by performing the steps of: [0110] Preparing a core composition by admixing 1 g of Bayhydur XP 2547 (ex Covestro), 4 g of Takenate D110N (ex Mitsui) and 30 g of perfume composition (ex Givaudan) in a reactor equipped with a stirrer; [0111] Stirring the core composition for 10 minutes at 600 rpm; [0112] Adding 40 g of water to the core composition and then adding 3 g of poly(methacrylamidopropyltrimethylammonium chloride-co-acrylic acid) copolymer having 71 mol-% methacrylamidopropyltrimethylammonium chloride and 29 mol-% acrylic acid, prepared according to WO 2016/207187 A1 (Example 1); [0113] Stirring the mixture obtained at 1100 rpm for 30 minutes in order to obtain an emulsion with a volume-average core composition droplet size (d50) of 10±2 μm; [0114] Adding 0.6 g of Lupasol G100, (ex BASF); [0115] Heating the mixture at a rate of 0.3° C./min; [0116] After 120 minutes, adding a mixture of 0.2 g chitosan with an average molecular weight of 200′000 g/mol (from shrimps, ex Acros), 0.4 g of 30 vol.-% acetic acid in water, and 10 g of water; [0117] Once the temperature of 85° C. has been reached, keeping the mixture for an additional 120 minutes at this temperature; [0118] Adding 4 g of a 20% ammonia solution in water and keeping the mixture for an additional 35 minutes; [0119] Letting the resulting mixture cool to 25° C. within 60 minutes, in order to obtain a slurry of microcapsules.

[0120] The solid content of the slurry was measured by using a thermo-balance operating at 120° C. The solid content, expressed as weight percentage of the initial slurry deposited on the balance, was taken at the point where the drying-induced rate of weight change had dropped below 0.1%/min. The ratio of the measured solid content to the theoretical solid content calculated based on the weight of perfume and encapsulating materials involved is taken as a measurement of encapsulation yield, expressed in wt.-%.

[0121] The solid content of the slurry obtained was 37 wt.-%, the volume average size (d50) of the capsules was 10±1 μm and the encapsulation efficiency was 100%.

[0122] In Example 1.1, the weight of the trifunctional isocyanate used in relation to the weight of the core composition provided was 11 wt.-% (Trifunctional isocyanate to perfume weight ratio: 0.13).

[0123] In Example 1.2, the microcapsules have been obtained by using the same process as in Example 1.1, but the weight of the trifunctional isocyanate used in relation to the weight of the core composition provided was 14 wt.-% (Trifunctional isocyanate to perfume weight ratio: 0.17).

[0124] In Example 1.3, the microcapsules have been obtained by using the same process as in Example 1.1, but the weight of the trifunctional isocyanate used in relation to the weight of the core composition provided was 19 wt.-% (Trifunctional isocyanate to perfume weight ratio: 0.25).

[0125] In Example 1.4, the microcapsules have been obtained by using the same process as in Example 1.1, but with mushroom chitosan having a molecular weight of 85′000 g/mol (ex Kionutrime).

[0126] In Example 1.5, the microcapsules have been obtained by using the same process as in Example 1.1, but with mushroom chitosan having a molecular weight of 15′000 g/mol (ex Kionutrime).

TABLE-US-00001 TABLE 1 Variations of polyisocyanate and chitosan types Trifunctional isocyanate (Takenate D110N) to perfume weight ratio Type of chitosan EXAMPLE 1.1 0.13 Shrimp (200′000 g/mol) EXAMPLE 1.2 0.17 Shrimp (200′000 g/mol) EXAMPLE 1.3 0.25 Shrimp (200′000 g/mol) EXAMPLE 1.4 0.13 Mushroom (85′000 g/mol) EXAMPLE 1.5 0.13 Mushroom (15′000 g/mol)

EXAMPLE 2—COMPARATIVE EXAMPLES

[0127] A series of microcapsules have been obtained by performing the process described in Example 1.1, wherein the Takenate D110N to perfume oil weight ratio and chitosan to perfume oil weight ratio have been varied according to Table 2.

[0128] In example 2.1 and 2.2, Takenate D110N was replaced by Desmodur W (methylenebis(4-cyclohexylisocyanate)).

TABLE-US-00002 TABLE 2 Variations of polyisocyanate and chitosan amounts Trifunctional Trifunctional isocyanate isocyanate (Takenate D110N) (Desmodur W) to perfume to perfume Chitosan to weight ratio weight ratio perfume ratio EXAMPLE 2.1 0 0.13 0 EXAMPLE 2.2 0 0.13 0.0067 EXAMPLE 2.3 0.08 0 0 EXAMPLE 2.4 0.08 0 0.0067 EXAMPLE 2.5 0.13 0 0

[0129] The reference samples 2.1 and 2.2 were not stable over storage, with 100% perfume leakage in shampoo base.

EXAMPLE 3—COMPARISON OF OLFACTIVE PERFORMANCE

[0130] The olfactive performance of the microcapsules was assessed by a panel of four experts who rated the odor intensity on a scale of 1-5 (1=barely noticeable, 2=weak, 3=medium, 4=strong and 5=very strong).

[0131] The samples were evaluated in unperfumed shampoo and in unperfumed hair care conditioner. The aforementioned slurries were added to these bases under gentle stirring with a paddle mixer, so that the level of slurry was 0.6 wt.-%, referred to the total weight of each base.

[0132] In the case of shampoos, 20 wt.-% of shampoo, based on the total weight of hair swatches, was applied on the swatches that were previously humidified with the same weight of water. The dry weight of each swatch was about 12 g.

[0133] In the case of hair conditioners, the swatches were previously washed with an unperfumed shampoo and rinsed with water. Then, 10 wt.-% of conditioner, based on the total weight of the swatches, was applied just after washing with the shampoo.

[0134] For both shampoos and hair conditioners, the swatches were submitted to a massage 20 sec and then rinsed 30 seconds under running tap water at 37° C. at a flow rate of 3.2 I/min, without touching the swatch by hand. For this evaluation, the swatches were handled carefully in order to minimize the risk of breaking the microcapsules mechanically. The pre-rub and post-rub olfactive evaluation was performed after drying the swatches for 24 h at room temperature (cold air dying). This evaluation was performed by gently combing one part of each swatch 5 times.

[0135] For evaluation involving hair dryer (hot hair drying), the hair swatches were let in air for 15 minutes. Then a standard hair dryer operating at an inner temperature of 180° C. and providing a volumetric air flow rate of 0.016 m.sup.3/s was placed at 5 cm apart from the hair swatch and the air flow was applied for 5 minutes while moving the air flow up and down the swatch during these 5 minutes. The temperature on the hair was about 40-45° C.

[0136] The results are shown in Table 3 and Table 4.

TABLE-US-00003 TABLE 3 Olfactive performance on hair swatch - shampoo case Perfume impact on dry brushed hair, after hot drying with hair dryer Sample aged for 2 Fresh sample weeks at 37° C. Reference microcapsules with 1.5 n.d. Takenate D110N to perfume ratio of 0.08; Without chitosan (EXAMPLE 2.3) Reference microcapsules with 1.3 n.d. Takenate D110N to perfume ratio of 0.13; Without chitosan (EXAMPLE 2.5) Microcapsules with Takenate 2.5 n.d. D110N to perfume ratio of 0.13; Shrimp chitosan 200′000 g/mol (EXAMPLE 1.1) Microcapsules with Takenate 2.5 2.2 D110N to perfume ratio of 0.13; Mushroom chitosan 85′000 g/mol (EXAMPLE 1.4) Microcapsules with Takenate 2.5 2.3 D110N to perfume ratio of 0.13; Mushroom chitosan 15′000 g/mol (EXAMPLE 1.5)

TABLE-US-00004 TABLE 4 Olfactive performance on hair swatch of freshly prepared and aged microcapsules - hair conditioner case Perfume impact on dry brushed hair, after drying with hair dryer Sample aged for 2 Fresh sample weeks at 37° C. Reference microcapsules with 1.7 n.d. Takenate D110N to perfume ratio of 0.08; Without chitosan (EXAMPLE 2.3) Reference microcapsules with 1.3 n.d. Takenate D110N to perfume ratio of 0.13; Without chitosan (EXAMPLE 2.5) Microcapsules with Takenate 1.3 n.d. D110N to perfume ratio of 0.08; Shrimp chitosan 200′000 g/mol (EXAMPLE 2.4) Microcapsules with Takenate 2.9 n.d. D110N to perfume ratio of 0.13; Shrimp chitosan 200′000 g/mol (EXAMPLE 1.1) Microcapsules with Takenate 2.5 2.0 D110N to perfume ratio of 0.17; chitosan (EXAMPLE 1.2) Microcapsules with Takenate 2.0 1.9 D110N to perfume ratio of 0.13; Mushroom chitosan 85′000 g/mol (EXAMPLE 1.4)

[0137] These results demonstrate the positive impact of combining Takenate D110N with chitosan on retaining the performance of microcapsules after hair drying with a hair drier, even after storage in shampoo and conditioner bases.