Transparent sunscreen

Abstract

The invention relates to a transparent sunscreen comprising a solution in which the solute is formed by a combination of five chemical solar filters in an amount of 25-40%, and the solvent is formed by a combination of oils comprising a first oil formed by dibutyl adipate in an amount of 5-15%, a second oil formed by isododecane in an amount of 40-55% and a third oil formed by dimethicone / bis-isobutyl PPG-20 crosspolymer in an amount of 5-15%, wherein the second and third oils are mixed in a ratio of 85:15 and the amount of the first oil with respect to the mixture of the second and third oils is in a ratio of 1:5.

Description

[0001] DESCRIPTION

[0002] Clear sunscreen

[0003] Technical field of the invention

[0004] The present invention pertains to the technical field of cosmetics and specifically to a sun protection product.

[0005] Background of the Invention

[0006] Protecting your skin from solar radiation is crucial, as skin health depends on it. Therefore, proper protection against UVA and UVB rays is essential to keep your skin healthy, preventing damage from solar radiation that can lead to premature aging, blemishes, or more serious health problems.

[0007] For this reason, it is necessary to use sunscreen on both the face and body. These sunscreens have been continuously improved and nowadays, for example, they can contain nutrients, as well as other skin-friendly compounds, which provide additional benefits to the product.

[0008] Furthermore, since they are most used in summer, during beach and pool hours, most sunscreens already have a water-resistant formulation, which allows the sunscreen to remain on the skin after swimming and thus continue to exert a protective effect despite having been in contact with water.

[0009] Despite all the evolution and improvements this product has undergone, it still presents some problems. These sunscreens often leave a whitish layer on the skin after application, and while this is acceptable when sunbathing at the beach or pool, in other situations, such as the workplace, the fact that the sunscreen leaves this white cast on the face is neither aesthetically pleasing nor appropriate. Therefore, many users prefer to forgo using sunscreen on their face regularly in their daily routine. Examples of the prior art include reference documents US2020113798, EP3056192, ES2484815, CN 107625660, and AU2014295502.

[0010] Document US2020113798 defines a transparent cosmetic composition with ultraviolet protection function, comprising an elastomer composition, an oil, and an organic ultraviolet protection agent that in turn comprises at least one liquid organic ultraviolet protection agent selected from the group consisting of ethylhexyl methoxycinnamate, ethylhexyl salicylate, homosalate, polysilicone-15, and p-isoamyl methoxycinnamate and at least one solid organic ultraviolet protection agent selected from the group consisting of ethylhexyl triazone, butyl methoxydibenzoylmethane, bis-ethylhexyloxyphenol methoxyphenyl triazine, and diethylamino hydroxybenzoyl hexyl benzoate.

[0011] The weight ratio of the mixture of at least one liquid organic ultraviolet protection agent and the solid is in the range of 3.5 to 5:1.

[0012] Document EP3056192 discloses a composition for use as a sunscreen comprising an organic silicone elastomer mixture formed by a crosslinked polymer of dimethicone / bis-isobutyl PPG-20 in isododecane in a concentration range of 30% to 90% w / w, a silicone elastomer formed by a crosslinked polymer of dimethicone / vinyl dimethicone and silica in a concentration range of 0.1% to 10% w / w, wherein the sunscreen is applied to the skin in the presence of water.

[0013] In both cases, an organic protective agent against ultraviolet rays, consisting of one or two compounds, is used. Given the dangers of exposure to this radiation, it is necessary to find ways to increase this protection as much as possible.

[0014] Finally, reference document ES2484815 deals with a transparent cosmetic sunscreen containing from 20 to 80% by weight of ethanol, from 15 to 45% by weight of oily components, liquid at 20°C, from 1 to 12% by weight of UV-A photoprotective filters from the group of compounds consisting of 2-(4'-diethylamino-2'-hydroxybenzoyl)-hexyl benzoate and 4-(tert-butyl)-4'-methoxybenzoylmethane, whose concentration data are referred to the total weight of the preparation.

[0015] In this sunscreen, the oily components that are liquid at 20°C are selected from the group of compounds consisting of C12-15 alkyl benzoate, octyldodecanol, phenethyl benzoate, coco-glyceride, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, homomentyl salicylate, ethylhexyl salicylate, isoamyl 4-methoxycinnamate, dibutyl adipate, 2-ethylhexyl 4-methoxycinnamate, cyclomethicone, and dimethicone. Furthermore, the water content of the preparation is a maximum of 4.5% by weight of the total weight of the preparation.

[0016] In this case, there is a proportion of water in the composition of the sunscreen, and it has been shown that the presence of water is the cause, among other things, of the whitish effect on the skin when applying sunscreen.

[0017] Another aspect to consider about this sunscreen is that it has a high percentage of alcohol, a component that, due to its volatility, provides a dry touch, which has the disadvantage of considerably drying out the skin after application and can be irritating.

[0018] Reference document CN 107625660 defines a transparent sunscreen gel whose formulation comprises a surfactant formed by one or at least one of sodium lipopeptide, lecithin or hydrogenated lecithin or at least the combination of the two.

[0019] The problem with this sunscreen is that it is an emulsion and uses water in its formulation, which causes the characteristic whitish effect of this type of product.

[0020] Document AU2014295502 defines a transparent sunscreen consisting of a transparent liquid that can be sprayed as an aerosol containing at least one ester of an α-hydrocarboxylic acid, at least one water-insoluble and solid organic UV filter, and at most 1% by weight of water and at most 1% by weight of ethanol.

[0021] In this case, although the problems associated with using alcohol and water in the formulation of this type of product are already indicated, they continue to use a percentage of both elements. What is necessary and advisable is to achieve a formulation that completely eliminates both components.

[0022] It is therefore necessary to solve these existing problems in order to maximize protection against ultraviolet rays and ensure that there are no aspects that would cause users to reject the application of the sunscreen, so that they can use it whenever they wish to protect their skin from the effects of the sun. Description of the invention

[0023] The transparent sunscreen presented here comprises a solution with a solute and a solvent, in which the solute is formed by the combination of five chemical sunscreens in a percentage between 25 and 40%, and the solvent is formed by a combination of oils.

[0024] This combination of oils comprises a first oil formed by dibutyl adipate, in a percentage between 5 and 15%, a second oil formed by isododecane, in a percentage between 40 and 55%, and a third oil formed by dimethicone / bis-isobutanol crosspolymer PPG-20, in a percentage between 5 and 15%.

[0025] Furthermore, these three oils appear in said combination in certain proportions such that the mixture of the second and third oil has a ratio of 85:15, and, in addition, the amount of the first oil with respect to said mixture of the second and third oil has a ratio of 1:5.

[0026] The transparent sunscreen proposed here represents a significant improvement over the state of the art.

[0027] This is because a formula for a sunscreen is achieved with a very high content of ultraviolet filters and with oils that act as a support for these filters by dissolving them and preventing their subsequent crystallization so that the high protection (SPF+50) is maintained.

[0028] In addition, this protector creates a water-insoluble film on the skin so that it can withstand contact with water and remain on the skin, providing protection against solar radiation.

[0029] Furthermore, the great advantage of this sunscreen is its formulation, achieved through an oil-based solution, thus avoiding emulsions and the presence of water in the formula. Emulsions, and especially water, are what cause the whitening effect when sunscreen is applied to the skin. In this way, a specific and precise combination of oils creates a solution of ultraviolet filters, resulting in a colorless and transparent sunscreen. This allows the product to be virtually invisible on the skin, as it is completely transparent and does not produce any whitening effect.

[0030] This creates an invisible, water-insoluble film on the skin, allowing for comfortable, discreet, and longer sun protection, making it easy for users to apply it wherever they go.

[0031] It is therefore a very effective sunscreen that solves the existing problem and allows anyone to apply sunscreen and be safe from the sun in any circumstance.

[0032] Detailed description of a preferred embodiment of the invention

[0033] In a preferred embodiment of the invention, the transparent sunscreen proposed herein comprises a solution with a solute and a solvent, wherein the solute is formed by the combination of five chemical sunscreens in a percentage between 25 and 40%, and the solvent is formed by a combination of oils.

[0034] This combination of oils comprises a first oil formed by dibutyl adipate, in a percentage between 5 and 15%, a second oil formed by isododecane, in a percentage between 40 and 55%, and a third oil formed by dimethicone / bis-isobutanol crosspolymer PPG-20, in a percentage between 5 and 15%.

[0035] Specifically, in this preferred embodiment, the percentage of the first oil is between 10 and 13%, the percentage of the second oil is between 45 and 48%, and the percentage of the third oil is between 6 and 9%.

[0036] Furthermore, these quantities must be such that the mixture of the second and third oils has a ratio of 85:15 and the quantity of the first oil with respect to said mixture of the second and third oils has a ratio of 1:5. In this preferred embodiment of the invention, the sunscreens are formed by ethylhexyl methoxycinnamate in a percentage between 5 and 15%, diethylamino hydroxybenzoyl hexyl benzoate, in a percentage between 5 and 15%, ethylhexyl triazone in a percentage between 1 and 8%, ethylhexyl salicylate in a percentage between 1 and 10%, and bis-ethylhexyloxyphenol methoxyphenyl triazine in a percentage between 1 and 10%.

[0037] In other embodiments, any other combination of UV filters from the list of authorized UV filters for cosmetic use may be used, with the corresponding restrictions on the use of each one.

[0038] In this preferred embodiment, the sunscreen also comprises at least one additive, which in this case consists of vitamins and anti-aging actives. In other embodiments, it may also contain a perfume, nutrients, or any other additive suitable for this use on the skin.

[0039] Once the protector was obtained in this preferred embodiment, a series of tests were carried out for water resistance, UVB SPF, UVA rays and transparency.

[0040] For the UVA protection value, the in vitro analysis method was carried out according to ISO 24443:2021 “Determination of sunscreen UVA photoprotection in vitro” and a protection value of 21.2 was obtained.

[0041] For the value of the sun protection factor, SPF UVB, the method of analysis used is the in vivo test on volunteers according to the ISO 24444:2019 standard. The value obtained in this case is 62.7 ± 4.1.

[0042] This UVB SPF factor is calculated through the ratio between the minimum dose to cause erythema on skin protected by a sun protection product and the minimum dose to cause erythema on the same unprotected skin.

[0043] For UVB protection, a minimum SPF of 6 must be guaranteed, as well as a UVA protection factor of 1 / 3 of the SPF. It is observed, therefore, that the obtained SPF value of 62.7 ± 4.1 meets this condition, and likewise, the obtained UVA protection factor of 21.2 also meets the requirement of being greater than or equal to one-third of 62.7, that is, greater than 20.9. A preliminary water resistance test was also performed on this sunscreen using a method according to ISO 16217:2020, "Water immersion procedure for determining water resistance."

[0044] This first method involves applying a controlled amount of product to a specific area of ​​each subject's skin and immersing them in water in a simulated swimming or jet spa test device for a designated period. After an additional drying period, both the unprotected and protected areas are exposed to ultraviolet light using the same procedure as in the test to determine static SPF according to ISO 24444:2019.

[0045] In addition, a second water resistance test was performed according to ISO 18861:2020, "Percentage of water resistance." Following the guidelines of this second test, the SPF of the sunscreen was compared before and after a period of immersion in water. The procedure used to obtain the SPF is the same as that of ISO 24444:2021, except that two SPF protection factors are obtained: the initial protection factor (SPFis) and the protection factor after contact with water (SPFiwr).

[0046] This test method indicates that the sequence should be 20 minutes of immersion in circulating water and 5 to 20 minutes of air drying without rubbing with a towel.

[0047] These immersions can be repeated to verify water resistance at 40 and 80 minutes. This checks whether the SPF value in contact with water remains the same or if its effectiveness changes after the different immersion times.

[0048] In order to determine the condition of "water resistant" in a sun protection product, it must continue to be effective after 40 or 80 minutes of immersion in water.

[0049] Thus, the transparent sunscreen analyzed here, after both the first and second water resistance tests, offers a result of "water resistant".

[0050] Furthermore, a series of additional tests were conducted to analyze the various physicochemical and microbiological specifications of the transparent sunscreen proposed here. The results are shown in Table 1.

[0051] Table 1

[0052] Table 1 shows that the results of this test, in terms of physicochemical specifications, indicate that the protector has a low density, making it very comfortable and easy to apply to the skin. Regarding the odor, it is indicated that it is standard, although this may vary depending on whether a perfume is added.

[0053] Regarding the color, after the corresponding test the result is a rating of "transparent, colorless" and this is due, as already indicated, to the preparation of this protector without the use of water or emulsifiers.

[0054] Finally, regarding microbiological specifications, there may be a very small amount of aerobic bacteria, molds and yeasts, less than the maximum limit established by cosmetic legislation, which is 1000 colony forming units per gram.

[0055] Furthermore, there is a total absence of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans.

Claims

CLAIMS 1- Transparent sunscreen, characterized in that it comprises a solution with a solute and a solvent, in which the solute is formed by the combination of five chemical sunscreens in a percentage between 25 and 40%, and the solvent is formed by a combination of oils comprising - a first oil formed by dibutyl adipate, in a percentage between 5 and 15%; - a second oil consisting of isododecane, in a percentage between 40 and 55%, and; - a third oil formed by dimethicone / bis-isobutanol crosspolymer PPG-20, in a percentage between 5 and 15%; wherein the mixture of the second and third oil has a ratio of 85:15 and the amount of the first oil with respect to said mixture of the second and third oil has a ratio of 1:

5. 2- Sunscreen according to claim 1, wherein at least one of the sunscreen filters is formed by ethylhexyl methoxycinnamate in a percentage between 5 and 15%. 3- Sunscreen according to any of claims 1 or 2, wherein at least one of the sunscreen filters is formed by diethylamino hydroxybenzoyl hexyl benzoate, in a percentage between 5 and 15%. 4- Sunscreen according to any of the preceding claims, wherein at least one of the sunscreen filters is formed by ethylhexyl triazone in a percentage between 1 and 8%. 5- Sunscreen according to any of the preceding claims, wherein at least one of the sunscreen filters is formed by ethylhexyl salicylate in a percentage between 1 and 10%. 6- Sunscreen according to any of the preceding claims, wherein at least one of the sunscreen filters is formed by bis-ethylhexyloxyphenol methoxyphenyl triazine in a percentage between 1 and 10%. 7- Sunscreen according to any of the preceding claims, comprising at least one additive. 8- Sunscreen according to claim 7, wherein the additive consists of a perfume and / or vitamins and / or anti-aging actives.

Images