The present invention belongs to the cosmetic field and relates to a cosmetic oil-in-water emulsion containing at least one antiperspirant active ingredient, at least one silicone oil and glycerol, characterized in that ratio by weight of the at least one silicone oil and the glycerol is in the range from 2:1 to 6:1. The cosmetic oil-in-water emulsion of the present invention is in particular suitable for the application with a roll-on applicator to the human skin. After application and drying the oil-in-water emulsion leaves only an insignificant amount of white marks behind on the skin and the applied emulsion does not feel sticky on the skin.

Antiperspirant products are commonly applied to the axillary region of the human body to prevent and/or reduce the sweat production. Technically this effect is achieved by

antiperspirant active ingredients blocking the sweat glands. Most commonly, those antiperspirant active ingredients are specific aluminum salts, which polymerize and thereby block the entrance of the sweat glands. Here, it should be noted that such a blocking of the sweat glands is only temporarily. The aluminum salts, which are most commonly used as antiperspirant active ingredients, are water soluble such that normal sweat production usually removes the polymerized aluminum salts within 72 hours from the sweat glands. In addition, the aluminum salts may be removed by washing the axillary region with water.

Standard commercial antiperspirant products are mostly formulated as aerosol, pump spray, roll-on preparation, cream or stick. The popularity of these products varies depending on the region. For example, in Europe most markets are dominated by aerosol and roll-on preparations, whereby in North America customers prefer to use antiperspirant sticks.

Roll-on preparations are applied from a reservoir container via a rotatably mounted ball by rolling the ball over the human skin.

Antiperspirant cosmetic compositions suitable to be applied with a roll-on applicator are usually either formulated as an alcoholic solution or as an oil-in-water emulsion. In the latter case, the oil compounds are included in the formulation, which allow for an enhanced skin caring effect. Additionally, due to a low content or the total absence of primary alcohols, such as ethanol, those oil-in-water emulsions can be applied to the skin after shaving without causing a burning effect. However, due to the presence of the water-soluble aluminum, zinc and/or aluminum zirconium salts in these oil-in-water emulsions, a number of adverse effects may become obvious upon application to the human skin. For example, when the oil-in-water emulsion is applied to the skin, the antiperspirant ingredient is still dissolved in the aqueous phase of the oil-in-water emulsion. But, after drying it is often found that white residues become apparent. These white residues may also be transferred from the skin to the clothes which is rather annoying for the customer.

One well known approach to reduce the appearance of white residues on the skin is to mask these residues with non-volatile oils such as alkyl benzoate and/or isopropyl palmitate. These oils prevent a complete drying of the formulation such that white residue do not become apparent on the skin. However, such a masking approach has the disadvantage that the masking oils may also be transferred to the clothes and thereby lead to fabric staining. Furthermore, the presence of the masking agents may cause a very sticky feeling, which is also not desirable for most customers. Accordingly, it is in particular problematic to provide composition, which leave a reduced amount of white residues behind after application to the skin and which do not feel sticky after application to the skin.

Therefore, it remains desirable to provide antiperspirant oil-in-water emulsions, which do not suffer the disadvantages discussed above. In particular it is desirable to provide an antiperspirant oil-in-water emulsion which leaves fewer white residues behind after application and which simultaneously feels less sticky and dries quickly upon application to the skin.

US 7776317 B2 discloses in example E5 an antiperspirant roll-on emulsion containing glycerol and cyclomethicone. However, in contrast to the present invention, glycerol was used in excess in relation to the cyclomethicone.

WO 2013182667 A2 discloses antiperspirant compositions, which are formulates as an emulsion. The objective of the described invention was to provide antiperspirant roll-on formulations which leave a reduced amount of white residues behind after application. On page 18 volatile silicone oils are disclosed as optional ingredient for the formulation. However, there is no disclosure for a composition according the present invention.

WO 9832418 A1 discloses clear antiperspirant composition with reduced fabric staining. Here, it should be emphasized that staining is a different effect in comparison to leaving white residues on the skin after application and drying. The water-in-oil emulsions disclosed in WO 9832418 A1 contain an antiperspirant active ingredient and at least one volatile silicone oil. However, there is no disclosure concerning a water-in-oil emulsion, concerning the addition of glycerol and selecting a specific ratio between volatile silicone oils and glycerol.

For this reason, none of the cited documents could direct the skilled person to the solution of the technical problem as proposed according to the present invention.

The present invention is a cosmetic oil-in-water emulsion containing

a) at least one antiperspirant active ingredient,

b) at least one volatile silicone oil, and

c) glycerol,

wherein the ratio by weight between the at least one volatile silicone oil b) and the glycerol c) is in the range from 2:1 to 6:1.

It was surprisingly found that the cosmetic oil-in-water emulsion according to the invention does not suffer the disadvantages of the prior art. In detail, it was surprisingly found that after application of the cosmetic oil-in-water emulsion to the skin a significantly reduced amount of white residues is left behind after drying. Simultaneously, the cosmetic oil-in-water emulsion feels less sticky on the skin and dries very quickly after application.

Therefore, another subject of the present invention is the use of the cosmetic oil-in-water emulsion according to the invention to provide an antiperspirant roll-on product, which leaves fewer white residues after application to the human skin and/or which feels less sticky upon application to the skin.

All the weight percentages (% by weight) given below relate, unless otherwise stated, to the total weight of the cosmetic oil-in-water emulsion. If ratios of certain components are disclosed in the following description, these ratios refer, unless otherwise stated, to weight ratios of the components.

Unless otherwise stated, all tests and measurements were performed under“normal conditions”. The term "normal conditions" refers to 20°C, 1013 hPa and a relative humidity of 50%.

For the purposes of the present disclosure, the term "free from" means that the proportion of the respective substance is less than 0.05% by weight. This ensures that entrainments or impurities with these substances are not included as "free from" according to the invention. The term“skin” refers solely to human skin.

According to the present invention, the cosmetic oil-in-water emulsion contains at least one antiperspirant active ingredient.

One group of preferred antiperspirant active ingredients, which is in accordance with the present invention, are aluminum salts, which may be selected from the following non-limiting list:

Aluminum salts such as aluminum chloride, AICI ₃ , aluminum sulfate, Al ₂ (S0 ₄ ) ₃ Aluminum chlorides of the empirical formula [Al ₂ (OH) _m Cl _n ], where m + n = 6 Aluminum chlorohydrate [Al ₂ (OH) ₅ Cl] ^c H ₂ 0

Standard Al complexes: Locron P (Clariant), Micro-Dry (Reheis), ACH-331 (Summit), Aloxicoll PF 40 (Giulini). - Capitalized Al complexes: Reach 501 (Reheis), AACH 324 (Summit), AACH 7171 (Summit), Aloxicoll P (Giulini), Aloxicoll SD100

Aluminum sesquichlorohydrate [AI ₂ (OH) _4,5 CI _{I ,} 5] ^x H ₂ 0 - Standard Al complexes: Aluminum sesquichlorohydrate (Reheis), AACH 308 (Summit) - Capitalized Al complexes: Reach 301 (Reheis)

Aluminum chlorohydrate [Al2(OH) ₄ Cl2] ^x H2O

Another group of preferred antiperspirant active ingredients which can be included in the cosmetic oil-in-water emulsion of the present invention are aluminum-zirconium salts. These aluminum-zirconium salts may be selected from the following non-limiting list:

Aluminum / zirconium glycine trichlorohydrex [AI ₄ Zr(OH)i3Cl3] * H ₂ 0 Gly - standard Al/Zr complexes: Rezal 33GP (Reheis), AZG 7164 (Summit), Zirkonal P3G (Giulini) - Capitalized Al/Zr complexes: Reach AZZ 902 (Reheis), AAZG- 7160 (Summit), Zirkonal AP3G (Giulini)

Aluminum / zirconium glycine tetrachlorhydrex [AI ₄ Zr(OH)i2CI ₄ ] ^c H ₂ 0 Gly - standard Al / Zr complexes: Rezal 36G (Reheis), AZG-368 (Summit), Zirkonal L435G (Giulini) - Capitalized Al / Zr complexes : Reach 908 (Reheis), AAZG-7167 (Summit), Zirkonal AP4G (Giulini)

Aluminum / zirconium glycine Pentachlorhydrex [Al8Zr(OH)23Cl5] ^c H ₂ 0 Gly Aluminum / zirconium glycine Octachlorhydrex [Al8Zr(OH)2oCl8] ^x H2O Gly Glycin-free aluminum /zirconium salts According to the present invention it is particularly preferred, if the at least one antiperspirant active ingredients is chosen from aluminum chlorohydrate and aluminum

sesquichlorohydrate. Most preferred is aluminum chlorohydrate.

It is also preferred if the total quantity of the at least one antiperspirant active ingredient is in the range from 5% to 15% by weight, more preferably 7.5% to 12.5% by weight and most preferably 9% to 11 % by weight, calculated to the total weight of the cosmetic oil-in-water emulsion.

The cosmetic oil-in-water emulsion of the present invention contains in addition to the antiperspirant active ingredient at least one volatile silicone oil. The term silicone oil generally conforms to polyalkylsiloxanes, preferably solely to polydimethylsiloxanes.

As used herein, the term“volatile” refers to those materials which have a measurable vapor pressure at normal conditions. A general description of non-limiting examples of volatile silicone oils can be found in the article“Volatile silicone fluids for cosmetics”, 91 Cosmetic and Toiletries 27-32 (1976).

Furthermore, the volatile silicone oils which are in accordance with the invention are preferably therein characterized that they have a kinematic viscosity in the range from 0.5 cSt (Centistoke) to 10 cSt, preferably 2 cSt to 6 cSt at 25°C. The kinematic viscosity of the volatile silicone oils can be determined using a glass capillary viscometer. The method is described in the publication of the American Society for Testing And Materials (ASTM), Philadelphia, Penn., ASTM D 445-94,“Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (the Calculation of Dynamic Viscosity)”.

In one embodiment of the invention the volatile silicone oil contained in the cosmetic oil-in- water emulsion is chosen from volatile linear silicone oils. Preferred linear silicone oils that are in accordance with the present invention are volatile linear silicone oils having 2 to 10 siloxane units as for example in the commercial products Dow Corning ® 200 (0.65 cSt),

Dow Corning ® 200 (1 ,5 cSt) and Dow Corning ® 200 (5 cSt) from Dow Corning.

In another embodiment of the invention the volatile silicone oil contained in the cosmetic oil- in-water emulsion is chosen from volatile cyclic silicone oils. Cyclic silicone oils are generally marketed under CTFA designation Cyclomethicone. Volatile cyclic silicone oils that are preferred according to the invention conform to the formula (I) wherein n is an integer in the range from 3 to 9, more preferably 4 to 6. These oils usually have a vapor pressure of about 13-25 Pa at 20°C.

Suitable cyclic volatile silicone oils for use herein include, but are not limited to the commercial products Mirasil CM5 (Bluestar Silicones) and Xiameter PMX-0245 (Dow Corning).

In terms of the present invention volatile cyclic silicone oils are chosen in favor of the volatile linear silicone oils. Therefore, it is preferred if the at least one volatile silicone oil is selected from volatile cyclic silicone oils, most preferred from volatile cyclic silicone oils which are in accordance with the formula I, wherein n is 5.

According to the invention the cosmetic oil-in-water emulsion contains glycerol. Thereby, it is preferred, if the quantity of glycerol is in the range from 0.5% to 2% by weight, more preferably 0.8% to 1.2% by weight, calculated to the total weight of the composition.

In addition, the ratio by weight between the at least one volatile silicone oil and the glycerol is in the range from 2:1 to 6:1 , preferably from 2.3:1 to 4:1 and most preferably from 2.5:1 to 3.5:1.

In a first preferred embodiment of the present invention the cosmetic oil-in-water emulsion contains

a) at least one antiperspirant active ingredient selected from aluminum chlorohydrate and aluminum sesquichlorohydrate,

b) at least one volatile silicone oil selected from volatile cyclic silicone oils which conform to the structure

wherein n is an integer in the range from 3 to 9, preferably 4 to 6, and

c) glycerol,

wherein the ratio by weight between the at least one volatile silicone oil b) and the glycerol c) is in the range from 2:1 to 6:1 , preferably from 2.3:1 to 4:1 and most preferably from 2.5:1 to 3.5:1.

Within the first preferred embodiment of the invention it is more preferred if the oil-in-water emulsion contains - calculated to the total weight of the cosmetic oil-in-water emulsion - a) 7.5% to 12.5% by weight at least one antiperspirant active ingredient selected from aluminum chlorohydrate and aluminum sesquichlorohydrate,

b) at least one volatile silicone oil selected from volatile cyclic silicone oils which conform to the structure

wherein n is an integer in the range from 4 to 6, and

c) 0.5% to 2% by weight of glycerol,

wherein the ratio by weight between the at least one volatile silicone oil b) and the glycerol c) is in the range from 2.3:1 to 4:1 and more preferably from 2.5:1 to 3.5:1.

Within the first preferred embodiment of the invention it is most preferred if the oil-in-water emulsion contains - calculated to the total weight of the cosmetic oil-in-water emulsion - a) 7.5% to 12.5% by weight, preferably 9% to 1 1% by weight aluminum chlorohydrate, b) at least one volatile silicone oil selected from cyclic silicone oils which conform to the structure

wherein n is an integer in the range from 4 to 6, and

c) 0.8% to 1.2% by weight of glycerol,

wherein the ratio by weight between the at least one volatile silicone oil b) and the glycerol c) is in the range from 2.5:1 to 3.5:1.

Furthermore, it is preferred if the cosmetic oil-in-water emulsion is a macro-emulsion. In terms of the present invention the term macro-emulsion is understood to be an emulsion therein characterized that the average diameter of the emulsified droplets exceeds 1 pm.

Within the meaning of the present invention, the "average diameter of the emulsified droplets" is preferably understood to be the volume-average droplet diameter D50, which can be determined by the conventional methods, for example by laser diffraction. The volume- average droplet diameter D50 is the point in the particle size distribution at which 50 vol.% of the emulsified droplets have a smaller diameter and 50 vol.% of the emulsified droplets have a larger diameter.

The cosmetic oil-in-water emulsion of the present invention is preferably therein

characterized that the total amount of the oil phase and lipid phase is in the range from 0.5% to 6.5% by weight, more preferably 2.5% to 4.5% by weight, calculated to the total weight of the cosmetic oil-in-water emulsion. By definition, emulsifiers are generally not included in the oil phase and lipid phase.

Furthermore, in terms of the present invention it is favorable if the oil-in-water emulsion is free from PPG alkyl ethers as these components may adversely affect the properties of the composition. The same is true for C12-15 alkyl benzoate.

Generally, it is preferred if the oil phase and lipid phase of the oil-in-water emulsion solely contains volatile silicon oils and perfume, wherein the perfume does preferably not exceed 1.2% by weight, calculated to the total weight of the cosmetic oil-in-water emulsion. It was further found that in accordance with the present invention the stability of the cosmetic oil-in-water emulsion can be increased by adding at least one nonionic emulsifier having an HLB value in the range from 12 to 18. Thus, preferred cosmetic oil-in-water emulsions of the present invention are therein characterized that at least one nonionic emulsifier having an HLB value in the range from 12 to 18 is contained.

According to the invention the nonionic emulsifiers having an HLB value in the range from 12 to 18 are preferably selected from linear saturated and unsaturated C12 to C24 primary alcohols that are etherified with 7 to 40 ethylene oxide units per molecule. In particular those nonionic emulsifiers having an HLB value in the range from 12 to 18 are preferred that are selected from Laureth, Trideceth, Myristeth, Ceteth, Steareth, Arachideth, and Beheneth, having respectively 7 to 40 ethylene oxide units per molecule. Nonionic emulsifier having an HLB value in the range from 12 to 18 that most preferred are selected from the group of Steareth-15, Steareth-20, Steareth-21 , Arachideth-20, Arachideth-21 , Beheneth-20,

Beheneth-21 , Ceteth-20, Ceteth-30, Ceteth-15, and Myristeth-15.

Further it is preferred if the cosmetic oil-in-water emulsion contains at least one nonionic emulsifier having an HLB value in the range from 12 to 18, preferably at least one of the above disclosed preferred and most preferred nonionic emulsifier having an HLB value in the range from 12 to 18, in a total quantity from 0.5% to 2% by weight, more preferably 1 % to 1.4% by weight, and most preferably from 1.1% to 1.3% by weight, calculated to the total weight of the cosmetic oil-in-water emulsion.

Preferred cosmetic oil-in-water emulsions are further therein characterized that they contain at least one nonionic emulsifier with an HLB value in the range from 3 to 6 to increase the stability of the emulsion. In this manner, it is avoided that the emulsion separates shortly after the preparation and the product experiences a prolonged shelf lifetime without changing its appearance.

Typical examples of preferred nonionic emulsifiers having an HLB value in the range from 3 to 6 are selected from linear saturated and unsaturated C12 to C30 primary alcohols that are etherified with 1 to 4 ethylene oxide units per molecule. More preferred nonionic emulsifiers having an HLB value in the range from 3 to 6 are selected from Laureth, Trideceth, Myristeth, Ceteth, Steareth, Arachideth, and Beheneth, having respectively 1 to 4 ethylene oxide units per molecule. Even more preferred are Steareth-1 , Steareth-2, Steareth-3, Ceteth-1 , Ceteth- 2, Ceteth-3, Myristeth-1 , Myristeth-2, Laureth-1 , Beheneth-2, Beheneth-3, and Beheneth-4, whereby Steareth-2 is chosen as the most preferred nonionic emulsifier having an HLB value in the range from 3 to 6.

Generally, it has to be pointed out that in terms of stability the combination of Steareth-21 as nonionic emulsifier having an HLB value of 12 to 18 and Steareth-2 as nonionic emulsifier having an HLB value in the range from 3 to 6 is most preferred.

Further cosmetic oil-in-water emulsions preferred according to the present invention are therein characterized that the weight ratio of the total quantity of the nonionic emulsifiers having an HLB value in the range from 12 to 18, especially the above disclosed preferred and most preferred nonionic emulsifiers having an HLB value from 12 to 18, and the total quantity of the nonionic emulsifiers having an HLB value in the range from 3 to 6, especially the above disclosed preferred and most preferred nonionic emulsifiers having an HLB value from 3 to 6, is in the range from 1 :1.2 to 1 :2, preferably 1 :1 .4 to 1 :1.8 and most preferably 1 :1 .5 to 1 :1 .7.

According to the present invention it is possible to include further emulsifier, however it is preferred if the emulsifiers included in the cosmetic oil-in-water composition are limited to those specified above, more preferably to Steareth-2 and Steareth-21.

Cosmetic oil-in-water emulsions, which are preferred according to the present invention, are also therein characterized that these contain at least one mineral. In one embodiment of the invention the mineral is chosen from the group of Talc, Perlite, Kaolin, Diatomaceous Earth and/or mica, whereby Diatomaceous Earth is most preferred. In another embodiment of the invention the at least mineral contained in the cosmetic oil-in-water emulsion is chosen from the group of minerals having an oil absorption capability from 20 ml/100g mineral to 350 ml/100g mineral, more preferably from 100 ml/100g mineral to 300 ml/100g mineral and most preferably from 200 ml/100g mineral to 250 ml/100g mineral. One suitable example of such a mineral having an oil absorption capability of 225 ml/1 OOg mineral is marketed under the trade name ImerCare 400D (S) by the company IMERYS. According to the invention the oil absorption capability of the mineral is determined according to the ASTM D-1483 - 12(2016) Standard Test Method for Oil Absorption of Pigments by Gardner-Coleman Method.

According to the present invention the minerals, especially the minerals described in the embodiments disclosed above are contained in a total quantity of 0.5% to 2% by weight, more preferably 0.75% to 1.25% by weight, calculated to the total weight of the cosmetic oil-in-water emulsion. According to the present invention it is additionally preferred if water is contained in the cosmetic oil-in-water emulsion in a quantity in the range from 60% to 90% by weight, more preferably 75% to 85% by weight, calculated to the total weight of the cosmetic oil-in-water emulsion.

The cosmetic oil-in-water emulsion of the present invention are intended to be applied to the human skin using a roll-on dispenser, such as known from commercial antiperspirant products. It was found that preferred cosmetic oil-in-water emulsions of the present invention are therein characterized that they have a viscosity in the range from 400 to 1500 mPa-s and preferably 500 to 1300 mPa-s at 35°C.

The viscosity of the cosmetic oil-in-water emulsion of the invention is determined at 35° C in a 150 ml beaker using a Rheomat R 123 by the company proRheo. The Rheomat R 123 is a rotational viscometer, i.e. a measuring body rotates in the substance to be measured. It measures the force required to rotate the measuring body in the sample at a predetermined speed. For this torque, the rotational speed of the measuring body and the geometric dimensions of the measurement system used, the viscosity is calculated. As a measuring body the measurement bob 1 (Part no. 200 0191 ) at a rotational speed range of 62.5 min -1 is used.

Examples:

The following examples should illustrate the compositions of this invention, without intending to limit the invention to these examples. The numerical values in the examples are percentages by weight, based on the total weight of the preparations.

Com = Comparative example, not according to the invention

Inv = Inventive example, according to the invention

*lmerCare 400D (S), IMERYS; ^** Mirasil CM5

The formulations according to the invention were prepared in the following manner. All ingredients of the 1. Part were melted at 75°C. Then the 2. Part (35°C) was added to the 1. Part. After mixing both the 3. Part was added and the mixture was homogenized. After homogenization the 4. Part was added. The 5. Part was added at a temperature of 30°C and the final composition was obtained after a final homogenization.

The viscosity of the example composition Inv. 1 was determined to be 500 mPa-s at 35°C using a Rheomat R 123 (See method disclosed in the description above).

The stickiness of the example compositions was evaluated in the following manner:

i) Circles with 2 cm diameter were marked on the forearms of each participant taking part in the study.

ii) Per marked section on the forearm 25 pg of one of the composition listed in the

following table was applied

iii) The compositions were evenly spread with a finger to form an evenly spread layer in the marked section. Then the stickiness of the compositions were evaluated by continuous repetition of pressing the fingertip onto the skin and removing the finger from the skin until the skin feels dry.

iv) The stickiness was rated on a scale from 1 to 5, wherein 1 means not sticky at all and 5 means very sticky.