ENCAPSULATED COMPOSITION

Abstract

Described is an encapsulated composition comprising at least one core-shell microcapsule. The at least one core-shell microcapsule comprises a core comprising at least one perfume and/or cosmetic ingredient, and a shell surrounding the core. The shell comprises a polymeric stabilizer that is formed by combination of a polymeric surfactant with at least one bipodal aminosilane. Disclosed is also a method of preparing an encapsulated composition and a use of such an encapsulated composition to enhance the performance of perfume and/or cosmetic ingredients in consumer goods.

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 perfume and/or cosmetic ingredient, and a shell surrounding the core, wherein the shell comprises a polymeric stabilizer that is formed by combination of a polymeric surfactant with at least one bipodal aminosilane.

2. The encapsulated composition according to claim 1, wherein the bipodal aminosilane is an aminosilane of Formula (I)
(O—R.sup.4).sub.(3-f)(R.sup.3).sub.fSi—R.sup.2—X—R.sup.2—Si(O—R.sup.4).sub.(3-f)(R.sup.3).sub.f   Formula (I) wherein X stands for —NR.sup.1—, —NR.sup.1—CH.sub.2—NR.sup.1—, —NR.sup.1—CH.sub.2—CH.sub.2—NR.sup.1—, —NR.sup.1—CO—NR.sup.1— or ##STR00004## R.sup.1 each independently stands for H, CH.sub.3 or C.sub.2H.sub.5; R.sup.2 each independently stands for a linear or branched alkylene group with 1 to 6 carbon atoms; R.sup.3 each independently stands for a linear or branched alkyl group with 1 to 4 carbon atoms; R.sup.4 each independently stands for H or for a linear or branched alkyl group with 1 to 4 carbon atoms; f stands for 0, 1 or 2.

3. The encapsulated composition according to claim 2, wherein the bipodal aminosilane is selected from the group consisting of bis(3-(triethoxysilyl)propyl)amine, N,N′-bis(3-(trimethoxysilyl)propyl)urea, bis(3-(methyldiethoxysilyl)propyl)amine, N,N′-bis(3-(trimethoxysilyl)propyl)ethane-1,2-diamine, bis(3-(methyldimethoxysilyl)propyl)-N-methylamine and 1,4-bis(3-(triethoxysilyl)propyl)piperazine.

4. The encapsulated composition according to claim 1, wherein the bipodal aminosilane is a secondary aminosilane.

5. The encapsulated composition according to claim 1, wherein the polymeric stabilizer is formed by combination of the polymeric surfactant with the at least one bipodal aminosilane and a further aminosilane, preferably an aromatic aminosilane, even more preferably selected from the group consisting of compounds having Formula II ##STR00005## wherein R.sup.1 stands for a linear or branched alkylene group with 1 to 6 carbon atoms; R.sup.2 each independently stands for a linear or branched alkyl group with 1 to 4 carbon atoms; R.sup.3 each independently stands for H or for a linear or branched alkyl group with 1 to 4 carbon atoms; f stands for 0, 1, or 2.

6. The encapsulated composition according to claim 5, wherein the aromatic aminosilane is selected from the group consisting of N-(3-(trimethoxysilyl)propyl)aniline and N-((trimethoxysilyl)methy)aniline.

7. The encapsulated composition according to claim 1, wherein the polymeric surfactant is a co-polymer of maleic anhydride and ethylene and/or vinyl methyl ether.

8. The encapsulated composition according to claim 7, wherein the co-polymer of maleic anhydride and ethylene and/or vinyl methyl ether is alternate.

9. The encapsulated composition according to claim 7, wherein the co-polymer of maleic anhydride and ethylene and/or vinyl methyl ether is fully or partially hydrolyzed.

10. The encapsulated composition according to claim 1, wherein the polymeric stabilizer is formed by combination of bis(3-(triethoxysilyl)propyl)amine with (3-(trimethoxysilyl)propyl)aniline and fully or partially hydrolyzed poly(ethylene-maleic anhydride) and/or poly(vinylmethylether-maleic anhydride).

11. The encapsulated composition according to claim 1, wherein the bipodal aminosilane to polymeric surfactant weight ratio is from 0.02 to 1.

12. The encapsulated composition according to claim 5, wherein the further aminosilane to polymeric surfactant weight ratio is from 0.02 to 1.

13. The encapsulated composition according to claim 1, wherein the shell additionally comprises at least one shell-forming material obtainable by: reacting an alkylolated polyfunctional amine or reacting a polyfunctional amine an aldehyde; reacting a polyisocyanate and a polyfunctional amine; reacting a polyfunctional amine and a polyfunctional (meth)acrylate; and/or reacting unsaturated monomers selected from the group consisting of styrene, divinylbenzene, alkyl (meth)acrilyates, polyfunctional (meth)acrylates, and vinyl monomes.

14. A method for preparing an encapsulated composition, in particular an encapsulated composition according to claim 1, the method comprising the steps of: a. Dissolving a polymeric surfactant in an aqueous phase; b. Dissolving at least one bipodal aminosilane in an oil phase comprising at least one perfume and/or cosmetic ingredient; c. Emulsifying the oil phase into the aqueous phase to form an oil-in-water emulsion; d. Causing the bipodal aminosilane and the polymeric surfactant to form a first shell of polymeric stabilizer encapsulating the dispersed oil droplets, thereby forming a slurry of microcapsules; and optionally: e. Providing additional shell-forming materials and causing them to react in order to form an additional shell encapsulating the microcapsules formed in step d.

15. (canceled)

16. (canceled)

17. A consumer good comprising an encapsulated composition according to claim 1, wherein the consumer good is preferably selected from the group consisting of fabric care detergents and conditioners, hair care conditioners, shampoos, heavy duty liquid detergents, hard surface cleaners, detergent powders, soaps, shower gels and skin care products.

18. A polymeric stabilizer which is formed by combination of a polymeric surfactant with a bipodal aminosilane.

19. (canceled)

20. The encapsulated composition according to claim 11, wherein the bipodal aminosilane to polymeric surfactant weight ratio is from 0.2 to 0.9.

21. The encapsulated composition according to claim 12, wherein the further aminosilane to polymeric surfactant weight ratio is from 0.1 to 0.7.

Description

EXAMPLE 1

[0136] Formation of microcapsules having first shell comprising a polymeric stabilizer according to the present invention:

[0137] In EXAMPLES 1.1 to 1.6, a series of core-shell microcapsules have been obtained, wherein the levels of polymeric surfactant (of ZeMac E400, ex Vertellus), bipodal aminosilane (bis(3-(triethoxysilyl)propyl)amine) and further aminosilane (((trimethoxysilyl)propyl)anilin) have been varied according to Table 1.

[0138] The microcapsules have been obtained by performing the steps of: [0139] a. Preparing a core composition comprising a well-defined amount (see Table 1) of bipodal aminosilane (bis(3-(triethoxysilyl)propyl)amine) and a well-defined amount (see Table 1) of further aminosilane (((trimethoxysilyl)propyl)anilin) by admixing both aminosilanes with 40 g of fragrance composition; [0140] b. Emulsifying the core composition obtained in step a. in a mixture of a well-defined amount (see Table 1) of ZeMac E400 in 39 g of water by using a 300 ml reactor and a cross-beam stirrer with pitched beam operating at a stirring speed of 600 rpm at a temperature of 25±2° C.; [0141] c. Adjusting the pH of the continuous phase of the emulsion to 4.4±0.5 with a 20% NH.sub.3 solution in water and maintaining the system at a temperature of 25±2° C. for 3.5 h while maintaining stirring as in step b.; [0142] d. Increasing the temperature to 80° C. for 1 h while maintaining stirring as in steps b. and c. to complete the formation of core-shell capsules; [0143] e. Letting the slurry of core-shell capsules obtained in step d. cool to room temperature.

[0144] The solid content of each of the slurries 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.-%.

TABLE-US-00001 TABLE 1 Formulation details for EXAMPLES 1.1 through 1.6 Dipodal Further ZeMac Encapsulation aminosilane aminosilane E400 yield [wt.-%] [wt.-%] [wt.-%] [wt.-%] EXAMPLE 1.1 0.2 — 1.5 40 EXAMPLE 1.2 0.5 — 1.5 90 EXAMPLE 1.3 0.5 — 0.75 <20 EXAMPLE 1.4 1.0 — 1.5 100 EXAMPLE 1.5 — 1.0 1.5 <20 EXAMPLE 1.6 0.5 0.5 1.5 100

[0145] As apparent from encapsulation yield, the presence of the dipodal aminosilane is a prerequisite for obtaining core-shell microcapsules having a high encapsulation yield. If the dipodal aminosilane is used alone with ZeMac E400, then optimal dipodal aminosilane to ZeMac E400 weight ratio range is from 0.3 to 0.7. If the dipodal aminosilane is used along with a further aminosilane and ZeMac E400, then the optimal dipodal aminosilane to ZeMac E400 weight ratio range is from 0.3 to 0.5 and the further aminosilane to polymer surfactant weight ratio in the emulsion is set within a range of from 0.3 to 0.5.

EXAMPLE 2

[0146] In EXAMPLE 2, microcapsules according to the prior art were prepared using the method described in US 2014/0331414 A1:

[0147] 462 g of water, 15 g of formic acid and 250 g of a 10% polyvinylpyrrolidone solution were introduced into a 1 L reactor under stirring. The stirring speed was set to 600 rpm and 200 g of perfume was added, followed by 44.6 g of methyl triethoxysilane, 16.4 g of tetraethoxysilane, 11.4 g of dimethyldiethoxysilane and 2.5 g of aminopropyltriethoxysilane at room temperature. After 2 h, the pH was slowly increased to 6 with a 20% sodium hydroxide solution and the temperature increased to 80° C. After 4 h at 80° C., the microcapsule slurry was slowly cooled to 25° C. A slurry of microcapsules of solid contents of 26% was obtained. The microcapsules had an average particle size of 17 micrometers.

EXAMPLE 3

[0148] In EXAMPLE 3, microcapsules having a first shell comprising a polymeric stabilizer according to the present invention and a second shell comprising an aminoplast resin were prepared by performing the steps of: [0149] a. Preparing microcapsules comprising the polymeric stabilizer as described in EXAMPLE 1.6; [0150] b. Adding 0.75 g of urea and 1.15 g of Luracoll SD (methylolated melamine pre-condensates ex. BASF), under continuous and stirring for 30 minutes at 35° C.; [0151] c. Increasing the temperature to 60° C. for 1 h and then to 80° C. for 1 h, while maintaining under stirring to obtain a slurry of microcapsules having a second shell of aminoplast resin surrounding the first shell comprising the polymeric stabilizer; [0152] d. Cooling down the slurry to room temperature.

EXAMPLE 4

[0153] In EXAMPLE 4, microcapsules having a first shell comprising a polymeric stabilizer according to the present invention and a second polyurea-based shell were prepared by performing the steps of: [0154] a. Preparing microcapsules comprising the polymeric stabilizer as described in EXAMPLE 1.6; [0155] b. Adding 2 g of hydrodispersible isocyanate based on hexamethylene diisocyanate (Bayhydur® XP2547, Covestro) and 22 g of diisocyanate 4,4-dicyclohexylmethanediyle (Desmodur® W1, Covestro) to the emulsion, while maintaining the system stirring as in step b. and c. of Example 1 at a temperature of 35±2° C. for 30 minutes; [0156] c. Adding 8 g of polyethyleneimine solution (Lupasol® G100 at 35% by weight in deionized water, BASF) in one step and heating reaction mixture gradually to 70° C. during 2 h; [0157] d. Adding 12.5 g of a 40 wt.-% aqueous solution of copolymer of acrylic acid and diallyldimethylammonium chloride (Merquat 281, Lubrizol) and further heating the reaction mixture to 85° C. for 2 h; [0158] e. Adding 410 g of ammonia solution and 3 g hydroxyethyl cellulose (Natrosol™ 250 HX, Ashland) and cooling down the mixture to room temperature. [0159] f. Adjusting the final pH of the suspension to 4.0±0.2 with citric acid solution.

EXAMPLE 5

Assessment of Leakage of Microcapsules in a Model Extractive Medium:

[0160] The model extractive medium was a system consisting of an aqueous solution of ethanol at an initial concentration of 30 vol.-% co-existing with an immiscible cyclohexane phase.

[0161] In a first step, 10 ml of cyclohexane was put into a vial. Then 1.8 ml of the 30 vol.-% ethanol in water was added to the vial. After equilibration, taking into account the partition coefficient of ethanol between cyclohexane and the water of 0.03, the percentage of ethanol in the aqueous phase was 25.2±0.5 vol.-% and the percentage of ethanol referred to the whole system was 2.4±0.05 vol.-%.

[0162] In a second step, the slurry to be assessed was diluted in such a way that the perfume concentration in the diluted slurry was about 10 wt.-% and 200 microliters of this diluted slurry was added to the vial.

[0163] In a third step, the vial was submitted to a horizontal mixing on an elliptic xy-mixing equipment operating at a 250 rpm for 4 h (shaking in the z direction was avoided).

[0164] In a fourth step, the upper cyclohexane phase containing the extracted perfume was analysed spectrophotometrically by using a UV/visible light spectrometer. The perfume concentration was determined by measuring the intensity of the absorbed UV/visible light at the maximum absorbance wavelength, which has been determined previously by using a reference perfume/cyclohexane solution of known concentration. This latter reference solution was used as an external standard for the quantification of the extracted perfume. The leakage value is defined as the percentage of the encapsulated perfume that has been recovered in the hexane phase.

[0165] Representative leakage values are given in Table 2, hereunder.

EXAMPLE 6

Assessment of Fragrance Release Performance:

[0166] The release performance of the microcapsule slurries was measured by using a texture analyzer (TA XT PLUS, ex TA instruments). 300 microliters of undiluted slurry were deposited on the surface of filter paper in three successive applications of 100 microliters and left to dry overnight. Then, the lower surface of a mechanical sensor probe, consisting of a flat metal cylinder having a diameter of 12.5 micrometer, was applied on the deposited microcapsules with a penetration velocity of 0.01 mm/s.

[0167] As the probe penetrates the bed of microcapsules deposited on the filter paper, it experiences a back elastic force which is proportional to the elastic bending modulus of the microcapsules, which is inversely proportional to the release performance of the microcapsules. The value of the measured force at the 50% deformation of the microcapsule bed is taken as a measurement of the release performance of the microcapsules. The displacement corresponding to 50% deformation point is determined as the half way point between the displacement point where the first contact with the microcapsules occurs, which is marked by the onset of a back force and the point where the probe motion is stopped by the filter paper.

TABLE-US-00002 TABLE 2 Perfume leakage in water/ethanol/cyclohexane and force at 50% deformation for selected examples Leakage at 30 vol.-% EtOH Force at 50% Example [wt.-%] deformation [N] EXAMPLE 1.4 50 1.7 EXAMPLE 1.6 25 3.0 EXAMPLE 2 100 2.9 EXAMPLE 3 <20 7.2 EXAMPLE 4 <20 6.9

[0168] It may be concluded from the value of the force at 50% deformation measured on the microcapsules of EXAMPLE 1.4 that the shells comprising the new polymeric stabilizer are solid and have a measurable elastic modulus. This result, combined with the limited leakage in model extractive medium, confirms that an encapsulating shell has been effectively formed in this example. The values for EXAMPLE 1.6 confirm that adding a further aminosilane effectively improves both mechanical stability and stability with respect to leakage. The leakage values of EXAMPLE 3 and 4 confirm the stabilizing effect of adding a second aminoplast shell. Finally, comparison with prior art microcapsules comprising conventional alkoxysilanes and aminopropyltriethoxysilane shows that the latter are much less stable with respect to leakage.

EXAMPLE 7

Comparison of Olfactive Performance of New and Conventional Silane-Based Microcapsules:

[0169] The olfactive performance of microcapsules of EXAMPLES 1.6, 3 and 4 according to the present invention have been compared with the olfactive performance of conventional silane-based microcapsules according to EXAMPLE 2. The samples were evaluated in a unperfumed hair care conditioner. The aforementioned microcapsule slurries were added to a hair care conditioner composition under gentle stirring with a paddle mixer, so that the level of slurry in the hair care conditioner base was 1 wt.-% referred to the total weight of the hair care conditioner base. 1.5 g of hair care conditioner was applied on 15 g swatches humidified with 12 g water. The swatches were submitted to a massage, left to stand for 1 minute and then rinsed 30 seconds under running tap water at 37° C. at a flow rate of 3.2 l/min, without touching the swatch by hand. The pre-rub olfactive evaluation was performed on the swatches after 4 h. For this evaluation, the swatches were handled carefully in order to minimize the risk of breaking the microcapsules mechanically. The post-rub olfactive evaluation was performed after drying the swatches for 24 h at room temperature. This evaluation was performed by gently rubbing one part of each swatch. The olfactive performance (intensity) was assessed by a panel of 4 experts rated on a scale of 1-5 (1=barely noticeable, 2=weak, 3=medium, 4=strong and 5=very strong). When relevant, qualitative comments on the perceived odor direction were recorded.

[0170] This evaluation was performed on fresh samples and on samples that have been stored for one month at 37° C.

TABLE-US-00003 TABLE 3 Olfactive performance on hair swatch of freshly prepared and aged microcapsules Pre-rub Pre-rub Post-rub Post-rub intensity intensity intensity intensity (fresh (aged (fresh (aged sample) sample) sample) sample) EXAMPLE 1.6 1.9 1.6 4.1 3.8 EXAMPLE 2 3.1 0.4 3.3 0.5 EXAMPLE 3 3.6 3.1 4.6 4.0 EXAMPLE 4 3.4 2.9 4.4 3.9

[0171] The results show that microcapsules according to the present invention provide significant enhancement of the perfume performance compared to conventional aminoplast silane-based microcapsules.