CORE-SHELL CAPSULES PREPARED WITH LINEAR AND CYCLIC ALIPHATIC POLYISOCYANATES

Abstract

The present invention relates to core-shell capsules prepared with linear and/or branched and cyclic aliphatic polyisocyanates. In particular, the present invention discloses a core-shell capsule, wherein the shell comprises or consists of a polymeric material which is produced or producible by reacting two components, the first component comprising or consisting of at least one linear aliphatic polyisocyanate and/or at least one branched aliphatic polyisocyanate having more than one isocyanate group, respectively, and at least one cyclic aliphatic polyisocyanate having more than one isocyanate group, the second component comprising or consisting of one or more crosslinking agent(s). Furthermore, a product comprising the present core-shell capsule, a process for producing the present core-shell capsules and the use of the present core-shell capsules is provided.

Claims

1. A core-shell capsule comprising: a shell comprising a polymeric material, wherein the polymeric material is produced or producible by reacting component (A) with component (B), wherein component (A) comprises at least one linear aliphatic polyisocyanate and/or at least one branched aliphatic polyisocyanate having more than one isocyanate group, respectively, and at least one cyclic aliphatic polyisocyanate having more than one isocyanate group, and component (B) comprises one or more crosslinking agent(s).

2. The core-shell capsule according to claim 1, wherein the at least one linear and/or the at least one branched aliphatic polyisocyanate or the at least one cyclic aliphatic polyisocyanate of component (A) are free of aromatic structure(s).

3. Core-shell capsule according to claim 1, wherein the linear or branched aliphatic polyisocyanate(s) is selected from the group consisting of pentamethylene diisocyanate, hexamethylene diisocyanate, ethyl ester lysine triisocyanate, lysine diisocyanate ethyl ester and derivatives thereof, and/or wherein the cyclic aliphatic polyisocyanate(s) is or are selected from the group consisting of isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 1,2-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, methylenebis(cyclohexyl isocyanate) and derivatives thereof.

4. The core-shell capsule according to claim 1, wherein the crosslinking agent(s) is a polyamine(s) with more than one amino group or salts thereof.

5. The core-shell Core shell capsule according to claim 1, wherein the capsule is a microcapsule, preferably is a microcapsule with a diameter of 2 to 500 μm.

6. The core-shell capsule according to claim 1, wherein the reaction is an interfacial reaction comprising contacting a first phase comprising component (A) with a second phase comprising component (B).

7. The core-shell capsule according to claim 6, wherein the first phase is dispersed in the second phase before the interfacial reaction and wherein the first phase further comprises one or more further ingredients of the core.

8. The core-shell capsule according to claim 6, wherein the second phase further comprises one or more colloidal stabilizer(s) to prevent coalescing of the first phase.

9. The core-shell capsule according to claim 4, wherein component (B) comprises 0.5 to 4 moles of amino groups per 1 mol of isocyanate groups present in component (A).

10. The core-shell capsule according to claim 1, wherein the core comprises one or more further ingredients selected from the group consisting of odorous substances, aroma molecules, cooling agents, TRPV1/TRPV3 modulators, dyes, dye precursors, phase change materials, catalysts for chemical reactions, adhesives, reactive substances for adhesive applications, pharmaceutical active substances, UV-filters, cosmetic active substances, plant protection active substances, insect repellents, water repellents, flame retardants, agrochemicals, lubricants and solvents.

11. A product comprising: the core-shell capsule of according to claim 1.

12. A process for producing the core-shell capsules comprising: (i) providing at least one linear aliphatic polyisocyanate and/or at least one branched aliphatic polyisocyanate having more than one isocyanate group, respectively, and at least one cyclic aliphatic polyisocyanate having more than one isocyanate group, one or more further ingredient(s) to be encapsulated, and optionally one or more solvent(s), (ii) providing one or more crosslinking agent(s), (iii) producing a solution (1) comprising the components of step (i), if applicable, wherein solution (1) is not water-soluble, (iv) producing a dispersion of solution (1) in an aqueous solution (2) of the component(s) of step (ii), optionally wherein the aqueous solution (2) further comprises one or more colloidal stabilizer(s), (v) reacting the polyisocyanates of solution (1) with the crosslinking agent(s) of solution (2), and (vi) optionally, subsequently maintaining the temperature of the reaction mixture in a range of 40 to 80° C. for 0.5 to 5 hours.

13. The process according to claim 12, wherein the linear or branched aliphatic polyisocyanate(s) of step (i) is selected from the group consisting of pentamethylene diisocyanate, hexamethylene diisocyanate, ethyl ester lysine triisocyanate, lysine diisocyanate ethyl ester and derivatives thereof, and/or wherein the cyclic aliphatic polyisocyanate(s) of step (i) is or are selected from the group consisting of isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 1,2-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanato-methyl)cyclohexane, methylenebis(cyclohexyl isocyanate) and derivatives thereof.

14. A core-shell capsule according produced or producible by a process as defined in claim 12.

15. A method for perfuming textiles, hair, skin, surfaces and/or ambient air by administering and/or releasing the core-shell capsule according to claim 1.

16. The core-shell capsule of claim 1, wherein a weight ratio of the total amount of said linear and/or branched aliphatic polyisocyanate(s) to the total amount of said cyclic aliphatic polyisocyanate(s) is from 90:10 to 10:90.

17. The core-shell capsule of claim 4, wherein the crosslinker(s) is selected from the group consisting of guanidine carbonate, guanidine hydrochloride, tris(2-aminoethyl)amine, ethylenediamine, butylenediamine, propanediamine, pentane-1,5-diamine, phenylenediamine, and linear or branched polyethyleneimines, and diethylenetriamine.

18. The core-shell capsule of claim 6, wherein (i) the polyisocyanate(s) of component (A) is water-insoluble and/or (ii) the crosslinking agent(s) of component (B) is water-soluble.

19. The core-shell capsule of claim 8, wherein the stabilizer(s) is selected from the group consisting of cellulose derivatives, low molecular surfactants, polyethylene oxides, and polyvinyl alcohols, polycations, polyanions, polyacrylamidosulfonates, and derivatives thereof.

20. The process of claim 12, wherein a weight ratio of the total amount of said linear and/or branched aliphatic polyisocyanate(s) to the total amount of said cyclic aliphatic polyisocyanate(s) is from 90:10 to 10:90.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0108] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0109] FIG. 1 shows a schematic view of a preferred embodiment of the process for producing core-shell capsules;

[0110] FIG. 2 shows the fragrance release from paper towels on which 0.2% aqueous dilutions of the capsule slurries have been sprayed;

[0111] FIG. 3 shows the fragrance release of capsules from freshly prepared fabric softener samples after kneading and after rubbing of the treated test fabric;

[0112] FIG. 4 shows the fragrance release from capsules stored for four weeks at 40° C. in fabric softener after kneading and after rubbing of the treated test fabric;

[0113] FIG. 5 shows the burst over time of core-shell capsules according to the present invention; and

[0114] FIG. 6 shows the fragrance release of capsules from freshly prepared fabric softener samples after kneading and after rubbing of the treated test fabric.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0115] In FIG. 1 a schematic view of an exemplary process according to the invention for producing core-shell capsules is shown. The internal phase is prepared by thoroughly mixing the isocyanate precursors, i.e. component (A) comprising or consisting of at least one linear aliphatic polyisocyanate and/or at least one branched aliphatic polyisocyanate having more than one isocyanate group, respectively, and at least one cyclic aliphatic polyisocyanate having more than one isocyanate group, with the fragrance and/or (an)other active ingredient(s). In a separate beaker, the external phase comprising a protective colloid is prepared in water by thoroughly mixing the constituents. In a next step the internal and external phases are thoroughly mixed for obtaining an emulsion of fragrance in water. Subsequently, the crosslinker(s) is/are added and mixing is continued until the core-shell capsules containing fragrance and/or other active ingredient(s) are cured. All steps are preferably performed under thorough mixing employing, for instance, a conventional turbine stirrer or dissolver disk. In general, high shear mixing/static mixing may be employed for preparing the emulsion.

[0116] Table 1 shows the analytical storage stabilities of the capsules in fabric softener.

TABLE-US-00001 TABLE 1 Examples of core-shell capsules prepared according to the invention containing the fragrance Tomcap/VOT (vegetable oil triglyceride). Ot 16 2049 Ot 16 2057 Ot 16 2059 Ot 16 2068 Ot 16 2074 Ot 16 2075 stability 94 93 98 97 95 96 in softener test formulation fresh [%] stability in 81 81 89 86 84 87 softener test formulation 1 week @40° C. [%] stability in 73 73 86 76 81 76 softener test formulation 4 week @40° C. [%] stability in 70 67 84 70 73 68 softener test formulation 8 week @40° C. [%] stability in 66 62 82 63 63 54 softener test formulation 12 week @40° C. [%] comment capsules capsules capsules capsules capsules capsules according according according not according according to the to the to the according to the to the state of invention invention to the invention invention the art invention ratio of see 4:6 2:8 see 1:1 4:6 isocyanates example 2 HDI:H6XDI HDI:H6XDI example 3 PDI:H6XDI PDI:H6XDI Free oil 0.1 0.0 0.2 0.1 0.1 0.1 total oil 16.8 13.8 14.1 16.6 15.3 16.2 particle size 22.5 28.7 25.8 23.2 25.5 25.8 D50 [μm] dry residue 38.7 34.2 33.8 34.5 35.5 33.9 [%]

[0117] Towels treated with fabric softener containing capsules according to the invention have been subjected to kneading and rubbing. The olfactory intensity of the samples was assessed on a scale from 1 to 9 before kneading, after kneading and after rubbing. The same has been performed for towels treated with unperfumed softener base. As expected, the unperfumed softener base does not show development of any significant odour. In all examples capsules prepared according to the invention show equal or higher intensities than the reference sample which have been prepared according to the state of the art. Capsules according to the invention freshly added to a fabric softener formulation (cf. FIG. 3) show the same tendency as capsules according to the invention after 4 weeks storage in fabric softener (cf. FIG. 4, at 40° C. and packed in plastic bags). The test shown in FIG. 3 has been repeated and the results have been confirmed (FIG. 6).

[0118] FIG. 5 shows the burst over storage time of the capsules in fabric softener. It is shown that all capsules prepared according to the invention show a significantly higher olfactory intensity after storage than the reference sample (capsules according to the state of the art) and unperfumed samples.

[0119] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments.

[0120] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practising the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

[0121] What has been stated herein with regard to the (preferred) embodiments of the core-shell capsules according to the invention applies accordingly to the products, processes and uses according to the invention described herein. Thus, the embodiments described herein are—as long as technically sensible—combinable with one another.

[0122] In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single element or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different independent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

[0123] In the following, the present invention will be described by way of examples, wherein the present invention is not limited to the examples below.

EXAMPLES

Example 1: Capsule Slurries According to the Invention

[0124] An external phase is created by dissolving 0.7 g of polyvinylalcohol (e.g. Celvol 523, ex. Sekisui Speciality Chemicals Europe, S.L. Spain) in 250 g deionized water. 5 g of H6XDI (e.g, Takenate 600 ex. Mitsui Chemicals Inc., Japan) and 5 g of PDI (e.g. Stabio D-376N ex. Mitsui Chemicals Inc., Japan) are dissolved in 95 g 266485 TOMCAP and 95 g 192060 VEGETABLE OIL TRIGLYCERIDE (both ex. Symrise AG Holzminden). This solution is emulsified in the external phase until a particle size distribution of approx. 20 μm is reached. A solution of 5 g guanidinium carbonate in 30 g of water (ex. Aldrich, Germany) is added and the system is heated up 70° C. This temperature is kept for 2-5 h under stirring. The solution is cooled to room temperature and 0.6 g of KelcoVis DG (ex. CP Kelco, France) is added.

Example 2: Capsule Slurries According to the State of the Art

[0125] An external phase is created by dissolving 2.5 g of polyvinylalcohol (e.g. Celvol 523, ex. Sekisui Speciality Chemicals Europe, S.L. Spain) in 250 g deionized water. 2 g of MDI (Fennocap 2301, ex. Kemira Chemicals, USA) and 8 g of HDI (Desmodur N 3400, ex. Covestro, Germany) are dissolved in 95 g 266485 TOMCAP and 95 g 192060 VEGETABLE OIL TRIGLYCERIDE (both ex. Symrise AG Holzminden). This solution is emulsified in the external phase until a particle size distribution of approx. 20 μm is reached. Then a solution of 5 g guanidinium carbonate (ex. Aldrich, Germany) in 30 g of deionized water is added and the system is heated up 70° C. This temperature is kept for 2-5 h under stirring. The solution is cooled to room temperature and 0.6 g of KelcoVis DG (ex. CP Kelco, France) is added.

Example 3: Capsule Slurries According to the Invention

[0126] An external phase is created by dissolving 0.7 g of polyvinylalcohol (e.g. Celvol 523, ex. Sekisui Speciality Chemicals Europe, S.L. Spain) in 250 g deionized water. 6 g of H6XDI (e.g, Takenate 600, ex. Mitsui Chemicals Inc., Japan) and 4 g of HDI (e.g. Desmodur N 3400, ex. Covestro, Germany) are dissolved in 95 g 266485 TOMCAP and 95 g 192060 VEGETABLE OIL TRIGLYCERIDE (both ex. Symrise AG Holzminden). This solution is emulsified in the external phase until a particle size distribution of approx. 20 μm is reached. Then a solution of 5 g guanidinium carbonate in 30 g of water (ex. Aldrich, Germany) is added and the system is heated up 70° C. This temperature is kept for 2-5 h under stirring.

[0127] The solution is cooled to room temperature and 0.6 g of KelcoVis DG (ex. CP Kelco, France) is added.

Example 4: Capsules not According to the Invention

[0128] An external phase is created by dissolving 0.7 g of polyvinylalcohol (e.g. Celvol 523, ex. Sekisui Speciality Chemicals Europe, S.L. Spain) in 250 g deionized water. 2 g of MDI (Desmodur M44, e.g, ex. Covestro, Germany) and 8 g of HDI (e.g. Desmodur N 3400, ex. Covestro, Germany) are dissolved 95 g 266485 TOMCAP and 95 g 192060 VEGETABLE OIL TRIGLYCERIDE (both ex. Symrise AG, Holzminden). This solution is emulsified in the external phase until a particle size distribution of approx. 20 μm is reached. Then a solution of 5 g guanidinium carbonate in 30 g of water (ex. Aldrich, Germany) is added and the system is heated up 70° C. This temperature is kept for 2-5 h under stirring. The solution is cooled to room temperature and 0.6 g of KelcoVis DG (ex. CP Kelco, France) is added.

Testing of Analytical Stability in Fabric Softeners

[0129] An unperfumed fabric softener test formulation having an ester quat content of approximately 17 wt.-% was mixed with 1 wt.-% of the capsule slurries and stored at 40° C. After a storage period of 1; 4; 8 and 12 weeks, respectively, the amount of fragrance raw materials diffused from the capsules into the base was determined with the aid of headspace measurements in the air phase above. The reported value is the percentage of fragrance oil still remaining in the capsule after storage.

Sensory Performance Testing

Method A

[0130] A 0.2% aqueous dilution of the obtained capsule dispersions are sprayed on paper towels (Katrin® Classic industrial towel XXL 2500 blue, Metsä Tissue GmbH, Kreuzau, Germany). After drying at ambient temperature for two days the sensory performance of the samples was tested. The olfactory intensity was determined by a panel of 5 experienced testers from the towels before kneading, after kneading and after rubbing. The olfactory intensity has been judged by a scale from 1 (no scent detectable) to 9 (very strong scent).

Method B

[0131] An unperfumed fabric softener test formulation was mixed with 0.3 wt.-% of capsule slurries. These samples have been stored for 0; 1; 4 and 8 weeks, respectively. In each case 20 g of the softener capsule slurry mixture were washed onto terrycloth towels in a standard European domestic washing machine. After the spin cycle, the towels were removed from the machine and line dried. Subsequently, the olfactory intensity was determined by a panel of 11 experienced testers from the towels before kneading (“untreated”), after kneading and after rubbing. The olfactory intensity has been judged by a scale from 1 (no scent detectable) to 9 (very strong scent).

Fabric Softener Test Formulation

[0132]

TABLE-US-00002 percentage Ingredient source by weight Water, demin. 82.68 Rewoquat WE 18 Evonik Nutrition and Care GmbH, 16.60 Germany Parmetol K 40 Julius Hoesch GmbH & Co. KG, 0.10 Germany Xiameter AFE-1520 Biesterfeld Spezialchemie GmbH, 0.30 Germany Magnesium chloride Sigma-Aldrich, Germany 0.32