Technical field

The present invention belongs to the cosmetic field, and relates to a sunscreen composition without cyclomethicones, especially in form of an emulsion, more especially in form of a W/O-emulsion.

Background art

In western countries, the trend away from genteel pallor towards “healthy, sporty brown skin” has been unbroken for years. In order to achieve this, people subject their skin to solar radia tion since this causes pigment formation in the sense of melanin formation. However, the ul traviolet radiation of sunlight also has a harmful effect on the skin. Besides the acute damage (sunburn), long term damage such as an increased risk of suffering from skin cancer, arises with excessive irradiation with light from the UVB range (wavelength: 280-320 nm). Moreo ver, too much UVB and UVA radiation (wavelength: 320-400 nm) leads to a weakening of the elastic and collagenous fibers of connective tissue. This may result in numerous phototoxic and photoallergic reactions, the effect being premature skin aging.

In Asian countries, a pale skin is preferred. Therefore, the people try to protect their skin from sunrays; this can be achieved by using an umbrella, avoiding sunlight, and/or using photo- protective cosmetic means.

In order to protect the skin by cosmetic photoprotective means, a series of photoprotective filter substances has therefore been developed, which can be used in cosmetic preparations. These UVA and UVB filters are summarized in most industrialized countries in the form of positive lists such as for instance Annex 7 of the German Cosmetics Regulation.

The effect of UV filters in a cosmetic preparation has to be determined; in general the sun protection factor (SPF) is used to characterize the sun protection potential of a cosmetic composition intended for the use as a sunscreen means. The sun protection factor (SPF) in dicates the increased time of exposure to the sun's rays made possible through use of the sunscreen composition. It is the ratio of the erythema threshold time with sunscreen compo sition to erythema threshold time without sunscreen composition.

Another test method, which has become established throughout Europe, is the Australian standard AS/NZS 2604:1997. Said standard involves the measurement of the absorption of the preparation in the UV-A range. To comply with the standard, the preparation must absorb at least 90% of the UV-A radiation in the range from 320 to 360 nm.

In general, to ensure a sufficient photoprotection a cosmetic composition may be character ized by SPF values of 20 or 50. To achieve this comparatively high photoprotection quite a high amount of UV filters has to be used in said compositions. This may result in composi tions, which are highly viscous or even paste-like and difficult to distribute. Moreover, said compositions may stay visible on the skin in form of white films.

However, consumers do like sun protection compositions, which have a light texture, are easily distributed and do not leave a greasy or oily feeling on the skin.

Sunscreen compositions, which are provided in form of a W/O emulsion, help to make availa ble a light product capable of being distributed in an easy and even manner.

A further means to ensure a pleasant skin feeling without any greasiness and oiliness is the use of cyclomethicones. As described in JP 2008195693, disclosing a water-in-oil emulsion sunscreen material, cyclic dimethylpolysiloxanes, amongst others, contribute to an improve ment with regard to spreadability and oiliness.

Additionally, US 5417961 A, disclosing with sunscreen compositions, describes that cy clomethicones influence the skin feel.

There are numerous documents in prior art disclosing sunscreen W/O emulsions containing cyclomethicones, only some of which will be cited: EP 1978916 A2, EP 2296610 A2, EP 2314271 A2, EP 2334283 A2, EP 2392312 A1, EP 2529727 A1, US 9034375 B2, US 7790146 B2, US 6919071 B2, WO 2007/091490 A1, WO 2007/097275 A1.

Concluding from prior art there is a considerable preference for including cyclomethiones in sunscreen compositions in form of W/O emulsions. Cyclomethicones may be characterized by the following formula: - - - n i

GHs wherein n is from 3 to 30.

In cosmetic preparations cyclomethicones with n representing 4 to 6 are mainly used. These components have the property to reduce the stickiness of cosmetic preparations. They are colorless and thin fluid.

According to new evaluations cyclotetrasiloxane (D4) is considered as presumably affecting fertility and being harmful for aquatic organisms. Furthermore, the degradability is slow and therefore this substance may be accumulated in living organisms.

Cyclopentasiloxane (D5) may be absorbed and resorbed by the human organism because of its high volatility.

Hence, it is desirable to replace cyclomethicones in cosmetic preparations.

Moreover, the sunscreen compositions without cyclomethicones should provide compositions with high SPFs, at the same time being easily spreadable, optionally available as very fluid compositions and/or water-resistant.

Summary of the invention

Surprisingly, all the above mentioned problems could be solved by a sunscreen composition, in form of a W/O emulsion containing • at least one oil, chosen from o at least one alkyl-methyl-siloxane, and/or o at least one ester and/or diester, with the proviso that the ester and/or diester is not a UV filter, and/or o at least one dialkylether and/or dialkylcarbonate, • at least one W/O emulsifier having a HLB value of 2 to 7,

• at least one UV filter.

Preferably, said sunscreen composition contains

• at least one oil, chosen from o at least one alkyl-methyl-siloxane, and o at least one ester and/or diester, with the proviso that the ester and/or diester is not a UV filter,

• at least one W/O emulsifier having a HLB value of 2 to 7, and

• at least one UV filter.

More preferably, said sunscreen composition contains

• at least one oil, chosen from o at least one alkyl-methyl-siloxane, and o at least one ester and at least one diester, with the proviso that the ester and diester are not UV filters,

• at least one W/O emulsifier having a HLB value of 2 to 7, and

• at least one UV filter.

Even more preferably said sunscreen composition contains

• at least one oil, chosen from o one alkyl-methyl-siloxane, and o one ester and one diester, with the proviso that the ester and diester are not UV filters,

• at least one W/O emulsifier having a HLB value of 2 to 7, and

• at least one UV filter.

In general, it is understood that emulsions are heterogeneous systems, which consist of two liquids which are immiscible or have only limited miscibility with one another and which are usually referred to as phases. In an emulsion, one of the two liquids is dispersed in the form of very fine droplets in the other liquid. The liquids (pure or as solutions) are present in an emulsion in a more or less fine distribution, which is generally of only limited stability.

If the two liquids are water and oil and oil droplets are present in finely distributed form in wa ter, then this is an oil-in-water emulsion (O/W emulsion, e.g. milk). The basic character of an O/W emulsion, exemplified by electrical conductivity, sensory properties, ability of the contin uous phase to be stained, is determined by the water. In the case of a water-in-oil emulsion (W/O emulsion, e.g. butter), the basic character is determined by the oil.

To stabilize an emulsion, one or more emulsifier(s) is/are contained in general.

Emulsifiers help to combine two immiscible liquids (for example oil in water) in a way to result in a stable preparation, an emulsion. For that reason emulsifiers have to have an amphiphilic character, the hydrophobic part interacts with the oily or lipid phase and the hydrophilic part interacts with the aqueous phase. By stirring or homogenizing the generated droplets are dis persed in the respective environment, namely aqueous droplets in a lipid environment or lipid droplets in an aqueous environment. Primarily, emulsifiers do not have a detersive, surfac tant character. Emulsifiers reduce the interfacial tension between the two phases and, be sides reducing the interfacial work, also achieve a stabilization of the emulsion formed. They stabilize the formed emulsion by means of interfacial films, as well as by forming steric or electrical barriers, as a result of which the merging (coalescence) of the emulsified particles is prevented.

HLB values are suitable to characterize emulsifiers, said values specify the hydrophilicity of a given emulsifier. The HLB value may be determined by the following formula:

HLB-20x(1 Mii _pophiie /M) , where Mii _P0Phiie represents the molar mass of the lipophilic fraction of a given emulsifier and M represents the molar mass of the total emulsifier.

In general, emulsifiers with an HLB value up to about 8 are considered to be W/O-emulsifi- ers. By contrast, O/W-emulsifiers have HLB values of greater than 8 to 15. Substances with HLB values greater than 15 are often referred to as solubilizers.

The sunscreen composition of the present invention contains at least one W/O-emulsifier, es pecially one having an HLB-value of 2 to 7.

The at least one W/O emulsifier may be chosen from Glycerylmonostearate, Glycerylmo- noisostearate, Glycerylmonomyristate, Glycerylmonooleate, Diglycerylmonostearate Diglyc- erylmonoisostearate Propylenglycolmonostearate, Propylenglycolmonoisostearate, Pro- pylenglycolmonocaprylate, Propylenglycolmonolaurate, Sorbitanmonoisostearate, Sorbitan- monolaurate, Sorbitanmonocaprylate, Sorbitanmonoisooleate, Saccharosedistearate, Poly- ethylenglycol(2)stearylether (Steareth-2), Glycerylmonolaurate, Glycerylmonocaprinate, Glycerylmonocaprylate, Polyglycerinpoly-12-hydroxystearat, PEG-30-dipolyhydroxystearat, Triglycerindiisostearat, Diisostearoyl Polyglyceryl-3 Dimer Dilinoleate, Polyglyceryl-4 isos tearate, Polyglyceryl-4 Diisostearate/Polyhydroxystearate/Sebacate and/or Polyclyceryl-3 Ricinoleate. Preferably the W/O emulsifier is Polyclyceryl-3 Ricinoleate.

The at least one W/O emulsifier may also be chosen from emulsifiers being silicone based, such as for example Cetyl PEP/PPG-10/1 Dimethicone.Lauryl PEG-10 Tris(Trime- thylsiloxy)silylethyl Dimethicone, PEP/PPG-18/18 Dimethicone, Cetyl Diglyceryl Tris(Trime- thylsiloxy)silylethyl Dimethicone, Cetyl PEP/PPG-10/1 Dimethiconebeing the preferred one. The emulsifiers may be purchased fromDow Chemical as Dowsil ES-5600 Silicone Glycerol Emulsifier, DowSil ES-5227DM formulation Aid, Dowsil ES-5300 formulation Aid, and Abil EM 90 from Evonik.

In the composition according to the present invention the at least one W/O emulsifier is con tained in a total amount of 0.2 to 1.2 % by weight, preferably 0.3 to 0.9 % by weight, in rela tion to the total weight of the composition.

The sunscreen composition according to the present invention contains at least one oil. The at least one oil may be derived from different chemical classes, but has to be fluid at room temperature.

The at least one oil may be selected from alkyl-methyl-siloxanes. Said alkyl methylsiloxane may be characterized by the following formula: wherein x is a number from 1 to 10, y is a number from 1 to 10 and R is an alkyl residue hav ing 2 to 10 carbon atoms. According to the invention it is preferred, if x and y have the number 1, more preferred are hexyl methicone and caprylyl methicone, most preferred is caprylyl methicone, which may be purchased from Momentive as Silsoft 034.

If the at least one oil is an alkyl methyl siloxane, the at least one alkyl methyl siloxane is con tained in an amount of 1.0 to 30 % by weight, preferably 2 to 8.0 % by weight, in relation to the total weight of the composition.

The at least one oil may be selected from esters and/or diesters of saturated and/or unsatu rated, branched and/or unbranched alkane carboxylic acids with a chain length of from 3 to 20 carbon atoms and saturated and/or unsaturated, branched and/or unbranched alcohols with a chain length of from 1 to 20 carbon atoms, and esters of aromatic carboxylic acids and saturated and/or unsaturated, branched and/or unbranched alcohols with a chain length of from 3 to 20 carbon atoms, with the proviso that said esters are fluid at room temperature. It is preferred, if the at least one oil is selected from esters and/or diesters of alcohols with a small number of carbon atoms, i.e. having 2 to 8 carbon atoms, for instance such as isopro panol, propylenglycol, neopentyl glycol and isopentyl alcohol and fatty acids. Examples of suitable oils are butylene glycol dicaprylate/dicaprate, phenethyl benzoate, C12-15 alkyl ben zoate, dibutyl adipate; diisopropyl sebacate, di-C12-13 alkyl tartrate, butyloctyl salicylate, di- ethylhexyl syringylidene malonate, hydrogenated castor oil dimerate, triheptanoin, C12-13 alkyl lactate, C16-17 alkyl benzoate, propylheptyl caprylate, caprylic/capric triglyceride, dieth- ylhexyl 2,6-naphthalate, caprylic/capric triglyceride, ethylhexyl Cocoate.

It is preferred, if isoamyl laurate is contained in the sunscreen composition according to the invention.

It is likewise preferred, if neopentyl glycol diheptanoate is contained in the sunscreen compo sition according to the invention. Using neopentyl glycol diheptanoate it is advantageous, if neopentyl glycol diheptanoate is used as a combination of neopentyl glycol diheptanoate with isododecane. In said combination neopentyl glycol diheptanoate is present in an amount of 20 to 40 % and isododecane is present in an amount of 60 to 80 %.

More preferably, both neopentyl glycol diheptanoate and isoamyl laurate are contained in the composition of the present invention, even more preferably is the usage of neopentyl glycol diheptanoate and isoamyl laurate, wherein neopentyl glycol diheptanoate is added as a mix ture of neopentyl glycol diheptanoate and isododecane. The at least one oil may be selected from at least one dialkylether and/or dialkylcarbonate, preferably the at least one oil is selected from dialkylcarbonates, more preferably dicaprylyl carbonate.

If the at least one oil is at least one ester and/or diester, said component(s) is/are contained in an amount of 5.0 to 30 % by weight, preferably 8.0 to 30 % by weight, in relation to the to tal weight of the composition.

The sunscreen composition of the present invention contains at least one UV filter; however to provide a composition having a sufficient and broad photoprotective potential, advanta geously a combination of UV filters is present, which absorb sun rays in a range of about 280 to about 400 nm. This may be achieved by a suitable combination of so called UV A and UV B filter or by using broadband filters or combinations thereof.

If the sun screen composition according to the present invention contains at least one UV B filter, said filter may be an oil-soluble or water-soluble one.

According to the present invention suitable oil-soluble UVB filters are: 3-(4-methylbenzylidene) camphor, 3-benzylidenecamphor; isoamyl p-methoxycinnamate; ethylhexyl cinnamate,

Ethylhexyl Salicylate (= I NCI);

2-hydroxy-4-methoxybenzophenone (I NCI: Benzophenone-3); 2,4,6-trianilino(p-carbo-2'-ethyl-T-hexyloxy)-1,3,5-triazine (INCI: Ethylhexyl Triazone), 2,4,-bis-{[4-(2-ethylhexyloxy)-2-hydroxy]phenyl}-6-(4-methox yphenyl)-1,3,5-triazine (INCI: Bisethylhexyloxyphenol Methoxyphenyl Triazine);

Octocrylene (= INCI).

According to the present invention suitable water-soluble UV B filters are: Phenylbenzimidazole Sulfonic Acid (= INCI) and salts thereof;

2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (INCI: Benzophenone-4) and salts thereof; and

Benzylidene Camphor Sulfonic Acid (= INCI) and salts thereof.

If the sun screen composition according to the present invention contains at least one

UV A filter, said filter may be chosen from

Diethylamino Hydroxybenzoyl Hexyl Benzoate (= INCI), and/or Butyl Methoxydibenzoylmethane (= I NCI).

In the composition according to the present invention the at least one UV filter is contained in a total amount of 1.0 to 25 % by weight, preferably 5 to 20 % by weight, in relation to the total weight of the composition.

According to the present invention the sunscreen composition may additionally contain at least one inorganic pigment based on metal oxides, which are insoluble or sparingly soluble in water, in particular the oxides of titanium ( PO2) and zinc (ZnO), or mixtures of such oxides, providing an additional photoprotective effect.

In the composition according to the present invention the at least one inorganic pigment is contained in a total amount of 1.0 to 25 % by weight, preferably 2.0 to 20 % by weight, in re lation to the total weight of the composition.

For the purposes of the present invention the inorganic pigments may be present in hydro- phobic form, i.e. the surface of said pigments has been treated in such a way that water is repelled. This surface-treatment may involve providing the pigments with a thin hydrophobic layer by processes known per se.

To achieve a photoprotection in the range of about 280 nm to about 400 nm a combination of one or more UV A filters, one or more UV B filters and optionally at least one inorganic pig ment is preferred. Even more preferred is a combination of Octocrylene, Ethylhexyl Salicylate and ZnO pigments.

However, likewise a further combination is even more preferred, namely a combination of Ethylhexyl Methoxycinnamate, Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine.

In further embodiments of the inventions it is advantageous, if the UV B filter Octocrylene and/or 2-hydroxy-4-methoxybenzophenone are not contained in the composition of the in vention.

According to the present invention the composition comprises an aqueous phase, the total amount of water ranges from 25 to 80 % by weight, preferably 25 to 50 % by weight, in rela tion to the total weight of the composition. According to the present invention the composition may additionally contain at least one moisturizer, preferably in a total amount of 1 to 5 % by weight, relative to the total weight of the composition. Moisturizers refer to substances or substance mixtures that give cosmetic preparations the property that, after application or distribution on the skin surface, the release of moisture from the corneal layer of the epidermis (also referred to as transepidermal water loss (TEWL)) is reduced and/or the hydration of the corneal layer is positively influenced. Ex amples of advantageous moisturizers within the meaning of the present invention include glycerin, lactic acid and/or lactates, in particular sodium lactate, butylene glycol, propylene glycol, Biosaccharide Gum-1, glycine soja, ethylhexylglycerin, pyrrolidone carboxylic acid, and urea. It is preferred, if butylene glycol is contained.

According to the present invention the composition may additionally contain at least one pre servative. All preservatives, which are allowed and suitable for cosmetic preparations may be contained. However, it is preferred, if methylparaben, ethylparaben, and Phenoxyethanol, or mixtures thereof are contained. Other preservatives may also be used, for example Benzyl Alcohol. These preservatives may be used alone or in combination or in combination with the above mentioned preferred preservatives.

If at least one preservative is contained in the composition of the present invention, the at least one preservative is preferably contained in a total amount of 0.1 to 0.9 % by weight, more preferably 0.4 to 0.6 % by weight, relative to the total weight of the composition. The values are referring to the active content of the preservatives.

Additionally, ethanol may be contained. Ethanol is a solvent and has a preservative effect. Ethanol may be contained as denatured alcohol. If ethanol is contained in the preparation of the present invention, the amount of ethanol ranges from 0.5 to 20 % by weight, preferably 0.7 to 10 % by weight, in relation to the total weight of the composition.

The cosmetic composition according to the invention may additionally contain fillers that fur ther improve, for example, the sensory and cosmetic properties of the formulations, and which, for example, impart or enhance a velvety or silky feel to the skin. Advantageous fillers within the meaning of the present invention are starch and starch derivatives (such as talc, silica, tapioca starch, distarch phosphate, aluminum or sodium starch octenylsuccinate, and the like), pigments without a primary UV filtering or coloring effect (such as boron nitride, etc.), and/or Aerosile* (CAS No. 7631-86-9) or silica dimethyl silylate. Additionally, a natural film former may be contained; a preferred example of such a film for mer is Capryloyl Glycerin/Sebacic Acid Copolymer, which may be purchased from Index un der trade name LexFilm Sun Natural.

According to the present invention the composition may additionally contain cosmetic auxilia ries, which areusually used in such compositions, e.g. preservative aids, complexing agents, electrolytes, perfumes, substances for increasing foaming, dyes, pigments which have a col oring action, fats, further oils, waxes or other common constituents of a cosmetic composi tion.

Examples

The examples below are intended to illustrate the present invention without limiting it. The numerical values in the examples are percentages by weight, based on the total weight of the particular preparations, given as active content.

Preparation method:

The composition of the present invention may be prepared by any technique known or effec tive to prepare a W/O-emulsion. The process to prepare the composition of the present in vention comprises conventional formulating and mixing techniques. However, it is preferred, if the preparation according to the present invention is prepared by the following method:

1. Mix and dissolve the polar oil(s), non-polar oil(s) and emulsifier(s) and other oil soluble components.

2. Mix and dissolve the water soluble components well.

3. Add the water soluble components slowly to oil soluble components while stirring to form the W/O emulsion.

The composition according to the invention preferably has a viscosity of 200 to 1000 mPa-s, more preferably 400 to 500 mPa-s. The viscosity is determined by using a Rheomat R123 at 25°C. Examples 1-7:

* mixture containing 30% Neopentyl Glycol Diheptanoate and 70 % Isododecane.

Experimental data:

To show that compositions according to the invention are easy spreadable and have compa rable, even better properties than a market product containing cyclomethicone and Cyclo pentasiloxane, often abbreviated as D5, a sensory evaluation was conducted.

*Anessa Perfect UV SunScreen Skincare Milk SPF50/PA++++

The market product was Anessa Perfect UV SunScreen Skincare Milk SPF50 PA of the com pany Shiseido. The I NCI listing revealed the following substances:

Aqua, Cyclomethicone, Ethylhexyl Methoxycinnamate, Polymethylsilsesquioxane, Alcohol, Dimethicone, Trimethyl Siloxysilicate, Polybutylene Glycol/PPG-9/1 Copolymer, Octocrylene, Isononyl Isononanoate, Phenylbenzimidazole Sulfonic Acid, Methyl Gluceth-10, C9-15 Fluoroalcohol Phosphate, Dipotassium Glycyrrhizate, Scutellaria Baicalensis Extract, Thy mus Serpyllum, Potentilla Erecta (Tormentil) Root Extract, Lauryl PEG-9 Polymethylsiloxy- ethyl Dimethicone, Triethanolamine, Aluminum Hydroxide, Stearic Acid, Acrylates/Dimethi- cone Copolymer, Silica, Cyclopentasiloxane, Isostearic Acid, Disteardimonium Hectorite, Trisodium EDTA, Butylene Glycol, BHT, Tocopherol, Phenoxyethanol, Perfume, Zinc Oxide. The sensory evaluation was conducted by 10 trained experts, which detect and describe the sensory properties as objectively as possible based on a standardized protocol and question naire.

Cohesiveness describes how a product deforms or strings rather than breaks when separat ing forefinger from thumb 3x quickly - that is, the length of the string before it breaks (0 - no strings; 10 - long strings).

This property was determined when having picked up the product from the packaging.

Soreadabilitv describes the ease of moving a product over the skin. An evaluation of the force needed to spread the product (0 - difficult to spread/drag; 10 - easy to spread/slip).

Thickness describes how thick a product feels between fingertip and skin - how much prod uct is present (denseness, residue) (0 - thin/no product; 10 - thick/high amount of product).

Wetness describes the amount of water perceived between fingertip and skin - how wet the product is (0 - not wet; 10 - high wetness).

Cooling describes the degree to which a product causes the skin to feel cool or cold after blowing lightly onto the skin (0 - not cool; 10 - high cooling).

The properties cohesiveness, thickness, wetness, and cooling were determined during appli cation of the product to the skin while rubbing 5 times in circles and 20 times in circles.

Gloss describes the amount or degree of light reflected off the skin (0 - dull; 10 - shiny).

Stickiness/adhesiveness describes the ease of separating the heel of the hand from the skin (0 - not sticky/tacky; 10 - very sticky/tacky).

The properties gloss and stickiness/adhesiveness were determined immediately after having applied the product on the skin.

The evaluation was performed using a scale of 0 to 10, where 0 to 0.5 means very slight, barely discernible,

0.5 to 2.0 means slight, 2.0 to 4.0 means slight-moderate,

4.0 to 6.0 means moderate,

6.0 to 8.0 means moderate-high 8.0 to 10.0 means high.

It becomes apparent that the inventive compositions are evaluated as good as the market product or nearly as good as the market product in many cases (spreadability 5 circles, wet ness 5 circles, spreadability 20 circles, stickiness immediate, and gliding immediate). Refer ring to properties such as cohesiveness, thickness 5 circles, cooling 5 circles, oily 20 circles, and gloss immediate the compositions of the invention are evaluated even better than the market product.

The problem of the present invention to provide sunscreen compositions containing high amounts of UV filter and at the same time being easily spreadable is solved as the evaluation concerning spreadability show.