Transparent aqueous sunscreen

Abstract

The invention relates to a water-based cosmetic preparation containing a) 0.2 to 10 wt.% 2-phenylbenzimidazole-5-sulfonic acid salts, b) 0.1 to 5 wt.% hydrolyzed corn starch with a glass transition temperature of at least -20°C, measured using DSC with a continuous heating rate of 10 K / min. in the range from -100 to 95°C, where the weight figures relate to the total weight of the water-based preparation.

Description

[0001] Description

[0002] Transparent, water-based sunscreen

[0003] The present invention relates to a water-based cosmetic preparation containing a) 0.2 to 10 wt% 2-phenylbenzimidazole-5-sulfonic acid salts, b) 0.1 to 5 wt% hydrolyzed corn starch (INCI: Hydrolyzed Corn Starch) with a glass transition temperature of at least -20 °C, measured by DSC, wherein the weight specifications refer to the total weight of the water-based preparation.

[0004] The trend away from a pale complexion and towards a "healthy, sporty tan" has been unbroken for years. To achieve this, people expose their skin to sunlight, as this stimulates pigment production in the form of melanin. However, the ultraviolet radiation in sunlight also has a damaging effect on the skin. In addition to acute damage (sunburn), long-term damage such as an increased risk of developing skin cancer occurs with excessive exposure to UVB light (wavelength: 280-320 nm). Furthermore, excessive exposure to UVB and UVA radiation (wavelength: 320-400 nm) leads to a weakening of the elastic and collagen fibers of the connective tissue. This results in numerous phototoxic and photoallergic reactions and premature skin aging.

[0005] To protect the skin, a number of sunscreen filters have been developed that can be used in cosmetic preparations. These UVA and UVB filters are listed in positive lists in most industrialized countries, such as Annex 7 of the Cosmetics Regulation.

[0006] However, the large number of commercially available sunscreens should not obscure the fact that these state-of-the-art preparations have a number of disadvantages.

[0007] Most cosmetic sunscreens are offered in the form of emulsions, oils, or ethanolic solutions. The fact that there are practically no purely aqueous sunscreens is primarily due to the fact that most UV filter substances are either soluble in ethanol or lipids. The lack of sufficient water-soluble UV filters for balanced and high UVA and UVB protection presents a major initial hurdle for experts in the development of aqueous products.

[0008] For aqueous systems, practically only UV filter substances based on sulfonic acids are suitable. Besides benzophenone-4 (IUPAC: 5-benzoyl-4-hydroxy-2-methoxybenzenesulfonic acid), these include in particular 2-phenylbenzimidazole-5-sulfonic acid, terephthalidene dicamphor sulfonic acid (INCI: Terephthalidiene Dicamphor Sulfonic Acid), and disodium phenylbenzimidazole sulfonic acid (INCI: Disodium Phenyl Dibenzimidazole Tetrasulfonate).

[0009] However, aqueous preparations containing these UV filters have a number of disadvantages: According to current technology, high sun protection factors cannot be achieved with such aqueous systems. They typically remain well below SPF 20.

[0010] Furthermore, such preparations have a very high spread value. This means they spread very quickly and heavily on the skin and drip off. Sunscreens with a high spread value would, in principle, be very appealing from a sensory perspective, as they feel light on the skin and are quickly absorbed. However, according to current technology, an even application of larger quantities of sunscreen to the skin is practically impossible due to the high spread values. According to general scientific knowledge, this problem is addressed by adding viscosity-regulating thickeners. While these thickeners reduce the spread value, they also increase the viscosity of the formulation. This makes it more difficult to spread on the skin, and the formulation feels relatively heavy and rich.Furthermore, transparent preparations can only be developed using polyacrylates, while cellulose- or starch-based polymers cloud the preparation or render it completely opaque. However, due to the discussion surrounding "microplastics," polyacrylates are increasingly undesirable among consumers (whether rightly or wrongly is irrelevant for the purposes of this disclosure). Therefore, the goal is to develop cosmetics that are as "polyacrylate-free" as possible.

[0011] The object of the present invention was therefore to develop a water-based cosmetic sunscreen that offers high UV protection (i.e., a sun protection factor of at least 20 and preferably a sun protection factor of 30). This water-based sunscreen should ideally be transparent (i.e., clear and see-through) and, although thin, should spread well in larger quantities on the skin without immediately running off upon application. Furthermore, the preparation should be free of polyacrylates and polyacrylic acid copolymers.

[0012] This problem is surprisingly solved by a water-based cosmetic preparation containing a) 0.2 to 10 wt% 2-phenylbenzimidazole-5-sulfonic acid salts, b) 0.1 to 5 wt% hydrolyzed corn starch (INCI: Hydrolyzed Corn Starch) with a glass transition temperature of at least -20 °C, measured by DSC with a continuous heating rate of 10 K / min in the range of -100 to 95 °C, where the weight specifications refer to the total weight of the water-based preparation.

[0013] A glass transition temperature of at least -20 °C means that higher temperatures (e.g., -10 °C, +10 °C, etc.) are within the scope of the invention, i.e., higher temperatures fall below the protected area. Furthermore, the value of the second measurement is decisive for the glass transition temperature determined by DSC.

[0014] The hydrolyzed corn starch according to the invention can be purchased, for example, under the trade name “MaizeCare Clarity Polymer” from Dow Chemical.

[0015] While the use of this cornstarch in cosmetics is known in itself, it has so far only been used as a "hair-styling polymer" in hair styling products.

[0016] According to the invention, it is preferred if the 2-phenylbenzimidazole-5-sulfonic acid salts are contained in the water-based preparation in an amount of 0.5 to 4% by weight, based on the total weight of the preparation.

[0017] According to the invention, it is preferred if the hydrolyzed corn starch (INCI: Hydrolyzed Corn Starch) with a glass transition temperature of at least -20 °C is included in the water-based preparation in an amount of 0.5 to 3% by weight, based on the total weight of the preparation.

[0018] Preferred embodiments of the present invention are characterized in that hydrolyzed corn starch (INCI: Hydrolyzed Corn Starch) with a glass transition temperature of at least -19 °C, measured by DSC with a continuous heating rate of 10 K / min in the range of -100 to 95 °C, is used. This is the case with the "MaizeCare Clarity Polymer" from Dow Chemical. According to the invention, it is advantageous if the water-based preparation is transparent. A preparation is considered "transparent" or "clear" within the meaning of the present invention if it is possible to see through a disposable cuvette (Brand, 2.5 ml, wavelength range: 220 nm–900 nm) filled with the preparation according to the invention with the naked eye in daylight. Text (Arial font, size 8) located directly behind the disposable cuvette must be clearly visible and legible.

[0019] It is advantageous according to the invention if the water-based preparation has a viscosity of less than 25 mPas. -1 , measured with measuring body 1 at 25°C.

[0020] According to the invention, the viscosity is measured as follows:

[0021] The measurement is taken at 25°C and a frequency of 10 1 rad / s in a 150 mL rolled-rim vial using the Rheomat R 123 from proRheo. Depending on the viscosity of the sample, measuring body 1 (up to 10 Pa·s) and measuring body 2 (from 10 Pa·s) are used. All viscosity measurements are always performed 24 hours after preparation of the sample.

[0022] If a balanced protection against IIV-A and UV-B radiation is to be achieved, it is advantageous according to the invention to use additional UV filters.

[0023] According to the invention, it is advantageous if the water-based preparation contains salts of 3,3'-(1,4-phenylenedimethylene)bis[7,7-dimethyl-2-oxo-bicyclo[2.2.1]heptane-1-methanesulfonic acid] (INCI: Terephthalidiene Dicamphor Sulfonic Acid) in an amount of 0.5 to 3.5% by weight, based on the total weight of the water-based preparation. An amount of 1 to 3% by weight, based on the total weight of the water-based preparation, is preferred according to the invention.

[0024] An advantageous alternative according to the invention is characterized in that the water-based preparation contains the disodium salt of 2,2'-(biphenyl-4,4'-diyldiethene-2,1-diyl)dibenzenesulfonic acid (INCI: Disodium Phenyl Dibenzimidazole Tetrasulfonate) in an amount of 0.5 to 3.5% by weight, based on the total weight of the water-based preparation. An amount of 0.5 to 3.0% by weight, based on the total weight of the water-based preparation, is preferred according to the invention.

[0025] According to the invention, it is particularly preferred if the preparation contains a combination of both UV filters (terephthalidiene dicamphor sulfonic acid and disodium phenyl dibenzimidazole tetrasulfonate). Preferred embodiments of the present invention are further characterized in that the sulfonic acid salts are a mixture of triethanolamine and sodium salts.

[0026] Such a mixture is obtained, in particular, by neutralizing (at least partially) the sulfonic acids of the three sulfonic acid groups of UV filters (2-phenylbenzimidazole-5-sulfonic acid, terephthalide dicamphor sulfonic acid, and disodium phenyl dibenzimidazole tetrasulfonate) with triethanolamine and sodium hydroxide solution. Particularly high sun protection factors can be achieved with formulations neutralized in this way.

[0027] It is advantageous within the meaning of the present invention if the water-based preparation contains water in an amount of at least 60% by weight, based on the total weight of the water-based preparation. A water quantity of at least 70% by weight, based on the total weight of the water-based preparation, is preferred according to the invention.

[0028] Furthermore, according to the invention, it is advantageous if the water-based preparation contains ethylhexylglycerin in an amount of at least 0.05 to 1.0% by weight, based on the total weight of the water-based preparation.

[0029] Furthermore, according to the invention, it is advantageous if the water-based preparation contains phenoxyethanol in an amount of at least 0.05 to 1.0% by weight, based on the total weight of the water-based preparation.

[0030] Furthermore, it is advantageous according to the present invention if the water-based preparation contains one or more alkanediols from the group consisting of 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol, 1,2-decanediol, and 2-methyl-1,3-propanediol. The use of 1,2-hexanediol is preferred according to the invention.

[0031] If, for various reasons, it is desirable for the preparation according to the invention to have a higher viscosity, it has proven advantageous according to the invention if the water-based preparation contains one or more gums (INCI: Gum).

[0032] According to the invention, it is preferred if the water-based preparation contains one or more gums selected from the group consisting of xanthan gum (INCI: Xanthan Gum), dehydroxanthan gum (INCI: Dehydroxanthan Gum), sclerotium gum (INCI: Sclerotium Gum) and / or carob gum (INCI: Ceratonia Siliqua Gum). Furthermore, according to the invention, the water-based preparation may advantageously contain hydroxypropyl guar to increase the viscosity.

[0033] Another advantageous component of the water-based preparation according to the invention is EDTA.

[0034] The water-based preparation according to the invention can, advantageously according to the invention, be used in two different forms: as an aqueous preparation, in particular as an aqueous spray or gel, and as the aqueous phase of an emulsion.

[0035] Therefore, according to the invention, it is advantageous if the water-based preparation is presented as an aqueous spray or gel.

[0036] On the other hand, according to the invention, it is advantageous if the water-based preparation forms the water phase of an emulsion.

[0037] In such a case, it is preferred according to the invention if the emulsion is in the form of an O / W emulsion. If such an O / W emulsion is present, one or more O / W emulsifiers are preferably selected from the group consisting of the following compounds: glyceryl stearate citrate, glyceryl stearate (self-emulsifying), stearic acid, stearate salts, polyglyceryl-3-methylglycosedearate, sodium cetearyl sulfate, potassium cetyl phosphate, polyglyceryl-10 stearate, and sodium stearoyl glutamate.

[0038] According to the invention, it is preferred if the preparation is free of polyethylene glycol, polyethylene glycol ethers and polyethylene glycol esters (so-called PEG derivatives), polyacrylates and polyacrylic acid copolymers.

[0039] Furthermore, according to the invention, it is advantageous if the preparation is free of polymers based on polyvinylpyrrolidone (PVP).

[0040] In particular, according to the invention, it is preferred if the preparation is free from parabens, methylisothiazolinone, chloromethylisothiazolinone and DMDM ​​hydantoin.

[0041] Furthermore, according to the invention, it can be advantageous if the preparation contains one or more active ingredients selected from the group of compounds alpha-lipoic acid, folic acid, phytoene, D-biotin, coenzyme Q10, alpha-glucosylrutin, carnitine, carnosine, natural and / or synthetic isoflavonoids, flavonoids, creatine, creatinine, taurine, β-alanine, panthenol, magnolol, honokiol, tocopheryl acetate, dihydroxyacetone; 8-hexadecene-1,16-dicarboxylic acid, glyceryl glycose, (2-hydroxyethyl) urea, vitamin E or its derivatives, hyaluronic acid and / or its salts, / V-[4-(2,4-dihydroxyphenyl)-1,3-thiazol-2-yl]-2-methylpropanamide (INGI: isobutylamido thiazolyl resorcinol) and / or licochalcone A.

[0042] Comparative experiments / execution example

[0043] The following recipes were produced and their transparency verified. 1 , glass transition temperature 4 , spread value 2 and sun protection factor 3 certainly: Composition Gotaras#142:

[0044] 1 The transparency was determined optically using the method described above. 2 The spread value is determined at 20 °C using the following method: 25 pl of the test solution are dispensed from an Eppendorf pipette from a drop height of 30 mm onto a round filter paper (Whatman 589 / 2, 110 mm ashless / white) placed centrally on a horizontal, smooth surface. The circular spread is determined after 10 minutes, and the diameter is measured at three points. The measurement is repeated five times, and the mean of all area measurements (area of ​​filter paper wetted by the test solution) is determined. The spread value is expressed in mm. 2 / 25pl and 10 min. specified.

[0045] 3The SPF is determined using the following method: The in-vitro SPF is measured on 3 or 4 PMMA plates (WW5, 3 using an older method, 4 using a newer method). The PMMA plates conform to Annex D of ISO method 24443 and are 5x5 cm in size. Before the product is applied to the PMMA plate, a vinyl finger cot is pre-conditioned with the product. Approximately 5-10 ml of the product to be measured is placed on the finger cot and rubbed against another PMMA plate for 90 seconds. After 90 seconds, the excess product is completely removed from the finger cot with a lint-free cloth. Following the ISO 24443 method, 1 liter of droplets are distributed as evenly as possible onto the PMMA plate using an Eppendorf pipette. A mass of 1.3 mg / cm² should be applied (total 32.5 mg + / - 0.5 mg). The mixture is then spread evenly with a finger (vinyl finger cot) for 90 seconds without applying pressure.After that, the coating is applied 10 times in each direction with a finger, applying greater pressure. Once the plate is coated, it is dried for at least 30 minutes at 35°C. The plate is then measured at at least 9 (12) evenly distributed points using the Labsphere UV2000 S. (Wl Labsphere).

[0046] 4 The glass transition temperature is determined using the following method: Sample preparation:

[0047] Dissolve sample in water (49-51% w / m)

[0048] Weight 9-12mg

[0049] Closed crucible

[0050] Measurement:

[0051] No pre-rinse, 10K / min heating rate, -100 to 95°C (without holding). Tg (Midlso) is, according to STARe, the temperature at which the bisector of the angle between the extrapolated baselines before and after the effect touches the DSC measurement curve.

[0052] The decisive factor is the value of the second measurement. Example recipes

[0053] The following examples are intended to illustrate the present invention without limiting it. Unless otherwise stated, all quantities, proportions, and percentages are based on the weight and total quantity or total weight of the preparations.

Claims

1. Water-based cosmetic preparation containing a) 0.2 to 10 wt% 2-phenylbenzimidazole-5-sulfonic acid salts, b) 0.1 to 5 wt% hydrolyzed corn starch (INCI: Hydrolyzed Corn Starch) with a glass transition temperature of at least -20 °C, measured by DSC with a continuous heating rate of 10 K / min in the range of -100 to 95 °C, wherein the weight specifications refer to the total weight of the water-based preparation.

2. Cosmetic preparation according to claim 1, characterized in that hydrolyzed corn starch (INCI: Hydrolyzed Corn Starch) with a glass transition temperature of at least -15 °C, measured by DSC with a continuous heating rate of 10K / min in the range of -100 to 95 °C, is used.

3. Cosmetic preparation according to one of the preceding claims, characterized in that the preparation is water-based and transparent.

4. Cosmetic preparation according to one of the preceding claims, characterized in that the water-based preparation has a viscosity of less than 25 mPas -1 , measured with measuring body 1 (RheoMat R123) at 25 °C.

5. Cosmetic preparation according to one of the preceding claims, characterized in that the water-based preparation contains salts of 3,3'-(1,4-phenylenedimethylene)bis[7,7-dimethyl-2-oxo-bicyclo[2.2.1]heptane-1-methanesulfonic acid] (INCI: Terephtalydiene Dicamphor Sulfonic Acid) in an amount of 1.0 to 3.5% by weight, based on the total weight of the water-based preparation.

6. Cosmetic preparation according to one of the preceding claims, characterized in that the water-based preparation contains the disodium salt of 2,2'-(biphenyl-4,4'-diyldiethene-2,1-diyl)dibenzenesulfonic acid (INCI: Disodium Phenyl Dibenzimidazole Tetrasulfonate) in an amount of 0.5 to 3.5 wt%, based on the total weight of the water-based preparation.

7. Cosmetic preparation according to one of the preceding claims, characterized in that the sulfonic acid salts are a mixture of triethanolamine and sodium salts.

8. Cosmetic preparation according to one of the preceding claims, characterized in that the water-based preparation contains water in an amount of at least 60% by weight, based on the total weight of the water-based preparation.

9. Cosmetic preparation according to one of the preceding claims, characterized in that the preparation is water-based and contains ethylhexylglycerin in a Contains a quantity of at least 0.05 to 1.0% by weight, based on the total weight of the water-based preparation.

10. Cosmetic preparation according to one of the preceding claims, characterized in that the water-based preparation contains phenoxyethanol in an amount of at least 0.05 to 1.0 wt%, based on the total weight of the water-based preparation.

11. Cosmetic preparation according to one of the preceding claims, characterized in that the water-based preparation contains one or more alkanediols from the group consisting of the compounds 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol, 1,2-decanediol, 2-methyl-1,3-propanediol.

12. Cosmetic preparation according to one of the preceding claims, characterized in that the water-based preparation contains one or more gums (INGI: Gum).

13. Cosmetic preparation according to one of the preceding claims, characterized in that the water-based preparation contains one or more gums selected from the group of compounds xanthan gum (INCI: Xanthan Gum), dehydroxanthan gum (INCI: Dehydroxanthan Gum), sclerotium gum (INCI: Sclerotium Gum) and / or carob gum (INCI: Ceratonia Siliqua Gum).

14. Cosmetic preparation according to one of the preceding claims, characterized in that the preparation is water-based and contains hydroxypropylguar.

15. Cosmetic preparation according to one of the preceding claims, characterized in that the water-based preparation contains EDTA.

16. Cosmetic preparation according to one of the preceding claims, characterized in that the preparation is water-based and is presented as an aqueous spray or gel.

17. Cosmetic preparation according to one of the preceding claims, characterized in that the water-based preparation forms the water phase of an emulsion.

18. Cosmetic preparation according to claim 17, characterized in that the emulsion is in the form of an O / W emulsion containing one or more O / W emulsifiers selected from the group consisting of glyceryl stearate citrate, glyceryl stearate (self-emulsifying), stearic acid, stearate salts, polyglyceryl-3-methylglycosederate, sodium cetearyl sulfate, potassium cetyl phosphate, polyglyceryl-10 stearate, sodium stearoyl glutamate.

19. Cosmetic preparation according to one of the preceding claims, characterized in that the preparation is free of polyethylene glycol, Polyethylene glycol ethers and polyethylene glycol esters (so-called PEG derivatives), polyacrylates and polyacrylic acid copolymers.

20. Cosmetic preparation according to one of the preceding claims, characterized in that the preparation is free of polymers based on polyvinylpyrrolidone (PVP).

21. Cosmetic preparation according to one of the preceding claims, characterized in that the preparation is free from parabens, methylisothiazolinone, chloromethylisothiazolinone and DMDM ​​hydantoin.

22. Cosmetic preparation according to one of the preceding claims, characterized in that the preparation contains one or more active ingredients selected from the group consisting of the compounds alpha-lipoic acid, folic acid, phytoene, D-biotin, coenzyme Q10, alpha-glucosylrutin, carnitine, carnosine, natural and / or synthetic isoflavonoids, flavonoids, creatine, creatinine, taurine, β-alanine, panthenol, magnolol, honokiol, tocopheryl acetate, dihydroxyacetone; Contains 8-Hexadecene-1,16-dicarboxylic acid, glyceryl glycose, (2-hydroxyethyl)urea, vitamin E or its derivatives, hyaluronic acid and / or its salts, / V-[4-(2,4-dihydroxyphenyl)-1,3-thiazol-2-yl]-2-methylpropanamide (INCI: Isobutylamido Thiazolyl Resorcinol) and / or licochalcone A.

23. Transparent packaging material containing a preparation according to one of the preceding claims.

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