USE OF ZEOLITE POWDERS IN COSMETIC FORMULATIONS

Abstract

The present invention refers to synthetic lipophilic zeolites powder for the preparation of cosmetic compositions.

Claims

1. A method of using zeolite powders to texturize a cosmetic composition, comprising incorporating a zeolite powder in a cosmetic composition. wherein said zeolite powders comprise ZSM-5 type zeolites, Linde Type A (LTA) zeolites or a mixture thereof; said zeolite powders characterized by a) a Si/Al ratio comprised between 1.0 and 25. b) a pore size comprised between 3.0 and 14 and a specific accessible area lower than 1700 m.sup.2/cm.sup.3, c) a Loose Bulk Density (LBD) value comprised between 100 and 700 kg/m.sup.3, d) a Fe (II)/(III) amount lower than 0.5% by weight, and e) sodium, potassium, calcium, or hydrogen as counter-ion at an ion exchange site of a framework structure.

2. (canceled)

3. The method of claim 1, wherein the zeolites have a surface functionalization realized through hydrolysis-condensation reaction with a silane suitable for the use in a cosmetic composition.

4. The method of claim 3, wherein the silane quantity is in amount comprised between 0.4 and 15% by weight with respect to the total zeolites weight.

5. The method of claim 1, wherein said zeolites are characterized by an oil absorption value comprised between 10 and 160 ml/100 g of powder measured by the analytical ASTM D281.

6. The method of claim 1, wherein said zeolites are characterized by a X.sub.90 value comprised between 0.1 and 30 m, measured according to the method ISO 13320:2020.

7. The method of claim 1, wherein said zeolites are characterized by a surface area comprised between 200 and 900 m.sup.2/g.

8. The method of claim 1, wherein the zeolites are used combined in an amount comprised between 1 and 75%, with respect to the total weight of the cosmetic composition.

9. The method of claim 1, wherein said cosmetic composition is a skincare composition.

10. The method of claim 1, wherein said cosmetic composition is a makeup composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0015] Specifically, it has been surprisingly found by the inventors that, by using synthetic lipophilic zeolites with well-defined technical features in a cosmetic formulation, it is possible to obtain a good spreadability and conformability on the skin, while avoiding unpleasant color and odor deriving from starting materials.

[0016] Therefore, the present invention, refers to zeolite powders, more preferably synthetic lipophilic zeolite powders as better defined below, for cosmetic formulations or compositions free of any plastic nano-fillers.

[0017] The adjective lipophilic refers to substances able of dispersing uniformly in oily or fatty phases, without the formation of deposits or precipitates.

[0018] Object of the invention is thus the use of zeolite powders for the preparation of a cosmetic formulation as defined by appended claim 1 and preferably comprising at least a synthetic lipophilic zeolite, more preferably Linde Type A (LTA) zeolites, ZSM-5 type zeolites or mixtures thereof, wherein said zeolites are characterized by a Si/Al ratio comprised between 1.0 and 50, preferably between 1.0 and 25, a pore size comprised between 3.0 and 14 , an accessible area per unit volume (i.e. specific accessible area) lower than 1700 m.sup.2/cm.sup.3 (1%) and a Loose Bulk Density (LBD) value comprised between 100 and 700 kg/m.sup.3.

[0019] The Loose Bulk Density (LBD), defined the mass of an uncompacted sample of the material divided by the volume that the sample occupies, measured in kg/m.sup.3. According to the particles shape and size, resulting LBD can be very different and it was surprisingly found by the inventors, that it can affect the texture and consistency of the final cosmetic product.

[0020] It is important to point out that the use of synthetic zeolites which, according to the present invention are characterized by a Fe (II)/(III) amount lower than 0.5% by weight, brings to several advantages for the cosmetic applications.

[0021] Specifically, contrary to natural zeolites which are typically characterized by the presence of common contaminants and impurities such as Fe.sub.2O.sub.3 or other metal oxides arising from natural source, the synthetic zeolites are in a purer form and, as a consequence, during the formulation further purification steps are not required. Moreover, said materials do not have the characteristic odor and color of the relative natural forms or other synthetic zeolites, with a consequent advantage for the formulation of cosmetic or skincare products which may require specific colors, odors or may have to be free from both.

[0022] Said zeolites preferably comprise sodium, potassium, calcium, or hydrogen as counter-ion at an ion exchange site of the framework structure.

[0023] In the field of filler particles, the use of surface modification can be an important factor to control the surface properties and their relative behavior when added to formulations, powder mixture, rubbers and other complex systems.

[0024] According to that, in a preferred embodiment, said zeolites are characterized by a surface functionalization realized through hydrolysis-condensation reaction with a silane suitable for the use in a cosmetic composition, such as Octyl trimethoxysilane or Caprylyl Triethoxy silane. According to said embodiment, the silane quantity is in amount comprised between 0.4 and 15% by weight with respect to the total zeolites weight.

[0025] A further feature to be considered, in order to improve the texture of a cosmetic formulation, is related to the oil absorption rate of the filler added. According to that, the zeolites herein disclosed can be further characterized by an oil absorption value comprised between 10 and 160 ml/100 g of powder, preferably between 20 and 100 ml/100 g, measured by the analytical ASTM D281, certified oil absorption method by Spatula Rub-out.

[0026] In a preferred embodiment, said zeolites are characterized by an X.sub.90 value comprised between 0.1 m and 30 m, preferably comprised between 0.2 and 10 m and a surface area comprised between 200 and 900 m.sup.2/g, preferably between 300 and 600 m.sup.2/g.

[0027] The X.sub.90 values, which indicates the spherical diameter at which 90% of the particles in the sample are comprised in the given range on a volume basis, have been determined using the analytical protocol defined according to the method ISO 13320:2020.

[0028] The surface area has been determined by suitable gas (CO.sub.2 or Ar) physisorption.

[0029] Inventors found that, in order to obtain optimal results in terms of the desired properties of the cosmetic formulation, the zeolite powders should be added to the cosmetic composition in an amount comprised between 1 and 75% by weight with respect to the total weight of the cosmetic composition; preferably in an amount comprised between 1 and 20% by weight in the case of a skincare product, and in amount comprised between 20 and 75% by weight in the case of a makeup product.

[0030] Indeed, it is finally disclosed that the synthetic lipophilic zeolite powders according to the present invention, are suitable to improve the texture performance of a skincare or a makeup composition.

[0031] Skincare or makeup compositions are as generally known to a person skilled in the art, and preferably they are preparations suitable for topical application in the form of gel, cream, ointment, powder, emulsions etc.

EXAMPLES

[0032] Hereinafter, the invention will be explained in more detail with reference to the following non-limiting examples. Modifications or variations of the embodiments here exemplified, obvious to an expert in the art, are encompassed by the appended claims.

[0033] Table 1 reports some examples according to the present invention, counter examples and their relative characterizations required for the use in a cosmetic composition. Specifically, since the color of an active ingredient is a key aspect for the formulation of a cosmetic composition, the results of a colorimetric test which allow to evaluate the intrinsic color of the zeolites are of high importance.

[0034] The color of zeolites powders is visualized and quantified by using the CIELAB color space. The 3-dimensional color space is built-up from three axes that are perpendicular to one another. The L-axis values gives the lightness: a white object has an L value of 100 and the L value of a black object is 0. The a-axis is the green-red axis and the b-axis goes from blue (b) to yellow (+b)

[0035] Each color is thus represented by a color point (L, a, b) in the color space; L, a and b are the color coordinates of the color point.

[0036] The test is made on compressed powder in a quartz sample container, using a state-of-the-art UV-Visible spectrometer equipped with an integrating sphere in reflection mode and recording the entire visible spectrum. The L, a and b parameters have been then calculated from the resulting spectrum according to CIELAB model.

TABLE-US-00001 TABLE 1 Samples Counter samples Ref. S1 S2 C1 C2 C3 C4 C5 Zeolites ZSM-5 LTA HEU ZSM-5 ZSM-5 ZSM-5 ZSM-5 framework (natural) Counter ion H+ Na+ Ca+ NH4+ NH4+ NH4+ NH4+ Si/Al (molar 11.5 1 6.4 25 40 140 11.5 ratio) Colorimetric 0.44 0.83 5.46 2.4 1.1 1.4 1.53 test (b value) Colorimetric 0.12 0.21 0.99 0.8 0.3 0.3 0.15 test (a value) Colorimetric 88.81 88.9 80.81 82.5 83.3 83.3 89.03 test (L value)

[0037] For the specific use in the cosmetic filed, it is necessary to avoid colors of the starting materials, specifically the yellowish shade, thus a combination of the L, a and b parameters which correspond to white and crystalline powders. Specifically, in order to ensure that, a b value lower than 1.0 is necessary to avoid the yellow shade of the zeolites.

[0038] According to that, it is clear that the zeolites disclosed in the present invention (samples S1-S2) ensure said characteristics, while natural zeolites such as the Heulandite type zeolite (HEU) (see C1), or synthetic zeolites with a Si/Al ratio higher than 50 (C4) or with different counter-ion (C2, C3, C5) does not fulfil the required colorimetric features.

[0039] A further aspect to be evaluate in the field of cosmetic ingredients is represented by their relative odor, which has to be neutral for the correct formulation of the final composition. According to that, the odor test is made by processing an appropriate amount of sample in a headspace vial at 80 C. and then injecting the headspace gas in a gas chromatograph equipped with a mass spectrum detector. The main VOC peaks are then quantified as ethyl acetate using an appropriate calibration and the total VOC amount from each sample is calculated.

[0040] Table 2 reports the relative results, specifically, the natural zeolite (C1) or the synthetic FAU type zeolites (C6-C7) with different Si/Al ratio present a VOC release which make them not suitable for the required application, while it is confirmed that the zeolites of the present invention (S1-S2) does not present any VOC release, thus making them texturizing starting materials which, at the same time, fulfil the required features of absence of color and odor.

TABLE-US-00002 TABLE 2 Samples Counter samples Ref. S1 S2 C1 C6 C7 Zeolites framework ZSM-5 LTA HEU FAU Y FAU Y (natural) Counter ion H+ Na+ Ca+ H+ H+ Si/Al (molar ratio) 11.5 1 6.4 15 30 Odor Test 2.6*10.sup.3 3.6*10 9.2*10.sup.3 GM-MS - 80 C. 3 (30% wt dispersion in CCT)