WO2023057177A1

WO2023057177A1 - Use of surfactants to provide a protective layer against pollution

Info

Publication number: WO2023057177A1
Application number: PCT/EP2022/075340
Authority: WO
Inventors: Anais IBARRA; Thais Leticia ROVIGATTI; Sonia Ariadne RAMIREZ; Leonardo Francisconi ADAMI; Yanel DE MORAL
Original assignee: Beiersdorf Ag
Priority date: 2021-10-05
Filing date: 2022-09-13
Publication date: 2023-04-13

Abstract

The present invention belongs to the cosmetic field.

Description

Use of surfactants to provide a protective layer against pollution

The present invention belongs to the cosmetic field and relates to a specific use of cosmetic ingredients allowing for an effective protection of the human skin from particulate matter by forming by protective layer or conditioning the skin in a way such that particulate matter does less adhere to the skin and can be washed away easily with tap water.

A beautiful and attractive appearance is a desire for many people. One typical sign of such an appearance is a healthy and smooth looking skin. Therefore, in order to take care on the skin, it is for many people a daily routine to apply cosmetic products such as cleansing formulations, in particular body wash or shampoo products.

One purpose of cosmetic products is to protect the human skin from environmental effects. For example, compositions containing UV-filters are commonly used to protect the skin from the ultraviolet radiation of the sunlight. In addition to the acute damage (sunburn), long-term damage such as an increased risk of skin cancer occurs in case of excessive irradiation with light from the UVB range (wavelength: 280-320 nm). The excessive exposure of UVB and UVA radiation (wavelength: 320-400 nm) also leads to a weakening of the elastic and collagen fibers of the connective tissue. This leads to numerous photo-toxic and photo- allergic reactions and results in premature skin ageing.

To protect the skin, a number of light protection filter substances have been developed, which can be used in cosmetic preparations. These UVA and UVB filters are grouped in the most developed countries in the form of positive lists such as Annex VI of the Regulation (EC) No 1223/2009 of the European Parliament and of the Council.

However, besides the sunlight the human skin is also exposed to many other environmental factors. For example, in some global regions it is problematic that due to the environmental pollution the concentration of fine particulate matter in the air is high. The term particulate matter is understood as solid matter suspended in the earth’s atmosphere. Sources of particulate matter can be natural or anthropogenic.

A special kind of particulate matter are particles from smog, tabacco smoke and flying ash, which appearance may be caused by forest fires, smoking or the exhaust of engines. Such particulate matter usually has a diameter in the range from 0.01 m to 100 pm, wherein smog and tobacco smoke typically cover the range from 0.01 pm to 2.5pm.

It is generally known that particulate matter, especially from smog and tobacco smoke, may adversely affect the human health. Inhalation of such particles may lead to an increased risk of lung cancer. However, high concentration of such particulate matter in the air also leads to an increased particle deposition on the skin. The correlation between high concentration of particulate matter in the air and the effect on the skin has recently been evaluated in a number of scientific studies.

For example, the disclosure “Premature skin aging by infrared radiation, tobacco smoke and ozone" by P. Schroder, S.M. Schieke and A. Morita (Skin Aging; Springer-Verlag; pp 45-55) discusses the effect of faster aging skin caused by tobacco smoke. Furthermore, a study by A. Vierkbtter, T. Schikowski, II. Ranft, D. Sugiri, M. Matsui, II. Kramer and J. Krutmann (Airborn Particle Exposure and Extrinsic Skin Aging, Journal of Investigative Dermatology 2010; 130; pp 2719-2726) indicated that the particle emission of engines may also correlate to a faster skin aging.

Cosmetic products are often used to protect the human skin from environmental effects. For example, the US2007/0003536 discloses a method for protecting human skin against oxidizing species and oxidative damages of the skin. Although the document is addressed to environmental effects, it does not address the easy and effective removal of particulate matter after deposition from the air.

Furthermore, the US2002/0192178 discloses a method for protecting the skin against the effects of pollution, comprising the application of a composition which contains an aqueous extract of maize. The extract of the invention is used as a heavy metal-scavening agent. However, the document does not address the easy and effective removal of particulate matter after deposition from the air.

Another example is the US patent application 2009/0035235, which describes a cosmetic composition that is capable of combating and preventing the effects of atmospheric pollution on the skin containing two vegetable extracts: Camellia sinensis (white tea) and Lapsana communis. The composition containing these two extracts exhibits an antiradical activity, provides protection against lipoperoxidation caused by exhaust gases and stimulates the mitochondrial respiration. Again, there is no disclosure in regard to an effective removal of particulate matter. Looking at the state of the art, it can be noticed that there are a number of documents addressing pollution effects. However, it is pointed out that none of the cited documents addresses compositions which can be applied to the skin before the exposure to the particulate matter and which allow an easy and effective removal of the deposited material with water after exposure.

Further, it can be noticed that cleansing formulations to be used as body wash are conventionally be used to remove particulate matter from the skin in the following manner:

1. Applying water to skin which has absorbed particulate matter

2. Applying the cleansing formulation to the wet skin

3. Washing off the cleansing formulation and the particulate matter with water.

In this way the skin is sufficiently cleansed. However, in the case that new particulate matter is deposited on the skin, the steps 1. to 3. have to be repeated to cleanse the skin again. Thus, the same amount of cleansing formulation is released due to step 3 in the sewage system a second time. However, in environmental terms it is of general interest to reduce the amount of cleansing formulations which is released in the sewage system.

Thus, it is desirable to provide ways to reduce the amount of cleansing formulation to be used.

It is desirable to provide a measures which allows to wash the skin a first time and a second time with water, whereby there is no need to apply a cleansing formulation a second time to allow for an effective removal of particulate matter, which is deposited on the skin after the wash.

It was surprisingly found by the application that the use of specific surfactants allows to address the points raised above. The use of other surfactants does not show the described effect.

A first object of the present invention is the use of cocamidopropyl betaine and/or an alkyl glycosides to condition the human skin such that particulate matter, which is deposited onto the skin after the skin is washed with a composition comprising cocamidopropyl betaine and/or an alkyl glycosides, can be rinsed off the skin with water. The term “washed” is understood as a process wherein the composition is applied to the human skin and consecutively rinsed off the skin with water. A further object of the invention is the use of a composition comprising cocamidopropyl betaine and/or an alkyl glycosides to form a protective layer or protective barrier on the human skin, whereby the protective layer or barrier allows particulate matter, which is deposited onto the skin after application of the composition, to be rinsed off the skin with water.

Preferably the protective layer or protective barrier is formed by applying the composition to the human skin and washing the composition off the skin with water, which happens before the particulate matter is deposited.

It was surprisingly noticed that after washing the human skin with the composition particulate matter, which is deposited after washing, may again be removed easily by rinsing the skin with tap water. Accordingly, the objectives of the present invention are solved.

All the weight percentages (% by weight) given below relate, unless otherwise stated, to the total weight of the cosmetic composition. 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%.

In the following description the terms ..according to the invention”, “preferred according to the invention” and so on are always directed to the use according to the invention and to the method according to the invention.

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 the human skin.

Emulsifiers are understood to be all substances which are listed in the International Cosmetic

Ingredient Dictionary and Handbook, Thirteenth Edition 2010, (ISBN 1-882621-47-6) under the name "emulsifying agent". Surfactants are understood to be all substances which are listed in the International Cosmetic Ingredient Dictionary and Handbook, Thirteenth Edition 2010, (ISBN 1-882621-47-6) under the name "surfactant".

The composition of the invention is preferably a cleansing composition, preferably a skin cleanser, body wash or shampoo.

According to the invention it is preferred if cocam idopropyl betaine is contained in the composition in a total quantity ranging from 2.0 to 10% by weight, more preferably 2.5 to 8.0% by weight and most preferably 3.0 to 6.0% by weight, calculated to the total weight of the composition.

It is also preferred if alkyl glycosides are contained in the composition in a total quantity ranging from 0.1 to 10% by weight, more preferably 0.5 to 8.0% by weight and most preferably 1.0 to 6.0% by weight, calculated to the total weight of the composition.

According to the invention it is preferred if the alkyl glycosides are chosen from lauryl glucoside, decyl glucoside and coco glucoside. Among those, lauryl glucoside is preferred.

For the case that lauryl glucoside, decyl glucoside and/or coco glucoside are contained, it is preferred if the total quantity of lauryl glucoside, decyl glucoside and/or coco glucoside is in the range from 0.1 to 10% by weight, more preferably 0.5 to 8.0% by weight and most preferably 1.0 to 6.0% by weight, calculated to the total weight of the composition.

It is preferred if the total quantity of lauryl glucoside is in the range from 0.1 to 10% by weight, more preferably 0.5 to 8.0% by weight and most preferably 1.0 to 6.0% by weight, calculated to the total weight of the composition.

The compositions according to the invention may further comprise components conveniently contained in cleansing formulations.

For example, it is preferred to add further surfactants such that the total quantity of surfactants ranges from 6.0 to 15% by weight, more preferably from 7.0 to 12% by weight, calculated to the total weight of the composition.

Typically, those further added surfactants may be anionic surfactants, which include: linear and branched fatty acids having 8 to 30 C atoms (soaps), ether carboxylic acids of the formula R — O — (CH2 — CH2O)x — CH2 — COOH, in which R is a linear or branched, saturated or unsaturated alkyl group having 8 to 30 C atoms and x=0 or 1 to 16, acyl sarcosides having 8 to 24 C atoms in the acyl group, acyl taurides having 8 to 24 C atoms in the acyl group, acyl isethionates having 8 to 24 C atoms in the acyl group, sulfosuccinic acid mono- and/or dialkyl esters having 8 to 24 C atoms in the alkyl group and sulfosuccinic acid monoalkylpolyoxyethyl esters having 8 to 24 C atoms in the alkyl group and 1 to 6 oxyethyl groups, alpha-olefinsulfonates having 8 to 24 C atoms, alkyl sulfate and/or alkyl polyglycol ether sulfate salts of the formula R — (OCH2 — CH₂)X — OSO3 "M⁺, in which R is a preferably linear or branched, saturated or unsaturated alkyl group having 8 to 30 C atoms, x=0 or 1 to 12, and M is an alkali or ammonium ion, sulfonates of unsaturated fatty acids having 8 to 24 C atoms and 1 to 6 double bonds, esters of tartaric acid and citric acid with alcohols, which are adducts of about 2-15 molecules of ethylene oxide and/or propylene oxide to fatty alcohols having 8 to 22 C atoms, alkyl and/or alkenyl ether phosphates of the formula,

in which R¹ preferably stands for an aliphatic hydrocarbon group having 8 to 30 carbon atoms, R² for hydrogen, a group (CH2CH2O)_nR¹ or X, n for numbers from 0 to 10, and X for hydrogen, an alkali metal or alkaline earth metal, or NR³R⁴R⁵R⁶, where R³ to R⁶ independently of one another stand for a Ci to C4 hydrocarbon group.

Preferred anionic surfactants are ether carboxylic acids of the aforementioned formula, acyl sarcosides having 8 to 24C atoms in the acyl group, sulfosuccinic acid mono and/or -dialkyl esters having 8 to 24 C atoms in the alkyl group and sulfosuccinic acid monoalkyl polyoxyethyl esters having 8 to 24C atoms in the alkyl group and 1 to 6 oxyethyl groups, alpha-olefinsulfonates having 8 to 24C atoms, and/or alkylsulfate salts and/or alkyl polyglycol ether sulfate salts of the aforementioned formula.

Especially preferred anionic surfactants are straight-chain or branched alkyl ether sulfates, which include an alkyl group having 8 to 18 and especially having 10 to 16 C atoms, and 1 to 6 and particularly 2 to 4 ethylene oxide units. Furthermore, especially preferred anionic surfactants are straight-chain or branched alkyl sulfonates, which include an alkyl group having 8 to 18 and especially having 10 to 16 C atoms. Preferred in particular are the sodium, magnesium, and/or triethanolamine salts of linear or branched lauryl, tridecyl, and/or myristyl sulfates, which have a degree of ethoxylation of 2 to 4.

Preferred compositions according to the invention are characterized in that they include at least one anionic surfactant from the group of alkyl sulfates and alkyl polyglycol ether sulfates of the formula R — (OCH2 — CH2)x — OSO3M, in which R preferably stands for a straight-chain or branched, saturated or mono- or polyunsaturated alkyl or alkenyl group having 8 to 24 carbon atoms, x for 0 or 1 to 12, and M for an alkali metal or alkaline earth metal or for triethanolamine, whereby anionic surfactants with the INCI name Sodium Lauryl Sulfate are especially preferred.

Other preferred compositions according to the invention are characterized in that the composition is free (meaning does not contain) from anionic surfactant from the group of alkyl sulfates and alkyl polyglycol ether sulfates of the formula R — (OCH2 — CH2)x — OSO3M, in which R preferably stands for a straight-chain or branched, saturated or mono- or polyunsaturated alkyl or alkenyl group having 8 to 24 carbon atoms, x for 0 or 1 to 12, and M for an alkali metal or alkaline earth metal or for triethanolamine.

In addition to cocam idopropyl betaine compositions may contain further amphoteric surfactants. One suitable further amphoteric surfactant is known under the INCI designation Disodium Cocoamphodiacetate.

Further compositions according to the invention may comprise oils to provide an extra caring effect. The oils can preferably be selected from mineral, natural, and synthetic oil components. However, natural and/or synthetic oils are more preferred than mineral oils.

Triglycerides and mixtures of triglycerides are usually employed as natural (plant) oils. Preferred natural oils are coconut oil, (sweet) almond oil, walnut oil, peach kernel oil, apricot kernel oil, avocado oil, tea tree oil, soybean oil, glycine soja oil, sesame oil, sunflower oil, tsubaki oil, evening primrose oil, rice bran oil, palm kernel oil, mango kernel oil, cuckoo flower oil, thistle oil, macadamia nut oil, grape seed oil, amaranth seed oil, argan oil, bamboo oil, olive oil, wheat germ oil, pumpkin seed oil, mallow oil, hazelnut oil, safflower oil, canola oil, sasanqua oil, jojoba oil, rambutan oil, cocoa butter, and shea butter. Glycine soja oil is preferred. Mineral oils, paraffin oils, and isoparaffin oils, and synthetic hydrocarbons in particular are used as mineral oils.

A dialkyl ether can serve furthermore as an oil. Dialkyl ethers which can be used are, in particular, di-n-alkyl ethers having a total of between 12 and 36 carbon atoms, particularly 12 to 24 carbon atoms, such as, for example, di-n-octyl ether, di-n-decyl ether, di-n-nonyl ether, di-n-undecyl ether, di-n-dodecyl ether, n-hexyl n-octyl ether, n-octyl n-decyl ether, n-decyl n- undecyl ether, n-undecyl n-dodecyl ether, and n-hexyl n-undecyl ether, as well as di-tert-butyl ether, di-isopentyl ether, di-3-ethyldecyl ether, tert-butyl n-octyl ether, isopentyl n-octyl ether, and 2-methylpentyl n-octyl ether.

Further oils preferred according to the invention are ester oils. Ester oils are understood to be the esters of C6-C30 fatty acids with C2-C30 fatty alcohols. The monoesters of the fatty acids with alcohols having 2 to 24 C atoms are preferred. Examples of employed fatty acid components in the esters are caproic acid, caprylic acid, 2-ethylhexanoic acid, capric acid, lauric acid, isotridecanoic acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, isostearic acid, oleic acid, elaidic acid, petroselic acid, linoleic acid, linolenic acid, elaeostearic acid, arachidic acid, gadoleic acid, behenic acid, and erucic acid, and technical mixtures thereof. Examples of the fatty alcohol components in the ester oils are isopropyl alcohol, caproic alcohol, caprylic alcohol, 2-ethylhexyl alcohol, capric alcohol, lauryl alcohol, isotridecyl alcohol, myristyl alcohol, cetyl alcohol, palmoleyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, elaidyl alcohol, petroselinyl alcohol, linolyl alcohol, linolenyl alcohol, elaeostearyl alcohol, arachyl alcohol, gadoleyl alcohol, behenyl alcohol, erucyl alcohol, and brassidyl alcohol, and technical mixtures thereof. Isopropyl myristate (Rilanit® I PM), isononanoic acid C16-18 alkyl ester (Cetiol® SN), 2-ethylhexyl palmitate (Cegesoft® 24), stearic acid 2-ethylhexyl ester (Cetiol® 868), cetyl oleate, glycerol tricaprylate, coconut fatty alcohol caprinate/caprylate (Cetiol® LC), n-butyl stearate, oleyl erucate (Cetiol® J 600), isopropyl palmitate (Rilanit® IPP), oleyl oleate (Cetiol®), lauric acid hexyl ester (Cetiol® A), di-n-butyl adipate (Cetiol® B), myristyl myristate (Cetiol® MM), cetearyl isononanoate (Cetiol® SN), and oleic acid decyl ester (Cetiol® V) are especially preferred.

Further, it is preferred if the oil contained in the emulsion is a PPG-alkyl ether. Preferred PPG-alkyl ethers are selected from the group defined by the formula

wherein / is an integer in the range from 4 to 20, and j is an integer in the range from 2 to 20.

Preferred PPG-alkyl ethers are defined by / being an integer in the range from 10 to 18 and j being an integer in the range from 10 to 16. More preferred is the PPG-15 stearyl ether.

Most preferred is the use of PPG-alkyl ethers as defined above and/or natural oils as described above.

Further, it is preferred if the composition comprises one or more further polymeric compounds. Polymeric compounds are preferably polysaccharides. It is preferred if the polymeric compound is an non-ionic polysaccharide. According to the invention it is preferred if the nonionic Polysaccharide is selected from natural gums. Natural gums are for example sclerotium gum and xanthan gum. It is particularly preferred if xanthan gum is included as nonionic polysaccharide.

Accordingly, it is preferred if a natural gum is included in the range from 0.02 to 1.2% by weight, more preferably 0.03 to 1.0% by weight, more preferably 0.04 to 0.8% and most preferably 0.05 to 0.7% by weight, calculated to the total weight of the composition.

In one embodiment of the invention it is preferred if nonionic emulsifier are contained. Although, basically all nonionic emulsifier can be contained in the composition of the invention, some emulsifiers were found to be particularly beneficial for the effect described. Preferred nonionic emulsifier are selected from oleth-20, glyceryl stearate, glyceryl stearate SE and PEG-40 hydrogenated castor oil.

Further, it was noted that it is beneficial according to the invention if the composition further comprises at least one fatty alcohol. Fatty alcohols are straight-chain primary alcohols containing 8 to 26 carbon atoms. For the case that at least one fatty alcohol is contained, it is preferred if the total quantity of the fatty alcohols is in the range from 0.05 to 4.0% by weight, more preferably 0.2 to 3% by weight and most preferably 0.5 to 2.5% by weight, calculated to the total weight of the composition. It is preferred if the composition is an oil in water emulsion. If the two liquids of an emulsion are water and oil and if oil droplets are finely distributed in water, then this is an oil in water emulsion (O/W emulsion, e.g., milk). The basic character of an O/W emulsion is determined by the water. In the case of a water-in-oil emulsion (W/O emulsion, e.g., butter), the principle is reversed, the basic character here being determined by the oil.

Further it is preferred if the composition is free from polymers polymerized from a mixture comprising acrylic acid and/or methacrylic acid. Such polymers were often used in the past. However, due to not known biodegradability these polymers should not be included in state- of-the-art formulations anymore. Accordingly, it is preferred if no polymers polymerized from a mixture comprising acrylic acid and/or methacrylic acid are contained.

Furthermore, it is advantageous if the cosmetic composition according to the invention contains water as cosmetic carrier in a proportion of 50% by weight to 98% by weight, preferably 60% by weight to 94% by weight and most preferably from 65% by weight to 95% by weight, based on the total weight of the composition.

Further it is preferred if the composition comprises sodium benzoate and/or sodium salicylate to ensure antimicrobial stability. For that purpose, it is preferred to have sodium benzoate and/or sodium salicylate contained in a total quantity ranging from 0.1 to 2% by weight, calculated to the total weight of the composition.

Further it is preferred if the composition comprises phenoxyethanol to ensure antimicrobial stability. For that purpose, it is preferred to have phenoxyethanol contained in a total quantity ranging from 0.1 to 1% by weight, calculated to the total weight of the composition.

The composition may further comprise sodium chloride in order to thicken the composition. Sodium chloride is preferably contained in quantities ranging from 0.1 to 1.5% by weight, calculated to the total weight of the composition.

According to the invention the composition may preferably contain at least one compound selected from the group of limonene, linalool, citral, alpha-isomethylionone and geraniol.

According to the invention it is further preferred if the composition has a pH value in the range from 4.5 to 8. The pH may be adjusted using citric acid or sodium hydroxide.

Examples: The following examples should illustrate the compositions and the use 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.

The following methodology was applied to analyze the effective removal of particulate matter after cleansing the skin with a composition followed by the exposure of the skin to particulate matter.

A group of participants has been selected for the study. The forearms of the participants were prepared by cleaning them with water, soap and ethanol. Afterwards several sections having a diameter of 2.5 cm were marked on the forearm. In each section 10 pl of one of the compositions as disclosed in the following table was applied. After absorption a photo was taken of each section. 30 minutes after application an excessive amount of charcoal powder (vegetable charcoal, 90% below 9.4 pm diameter, 10% below 2.5 pm diameter) was sprinkled over the marked sections ensuring that all sections were fully covered. The excessive amount of charcoal was then removed by flipping the arm 10 times until no further charcoal fell off.

To analyze the effectiveness of the removal of charcoal the marked sections were washed by pouring water onto the sections for 10 seconds. Afterwards, the amount of removed charcoal was evaluated by taking a second photo of the relevant section.

The photos were analyzed using the software Imaged. For that purpose, the total area in % of black sections in both, the image before application of the charcoal and after washing off the charcoal within the relevant marked section were determined.

The experimental results are indicated in the following table containing example formulations. The formulations Ex.1 and Ex.3 are according to the invention. The remaining formulations are non-inventive reference examples.

The test performed allowed a superior removal score for the inventive examples, as shown in the table. These are indicated by lower increase of the black area as shown in the difference in % area in the last

Further formulations are indicated in the table below:

Claims

1. Use of cocamidopropyl betaine and/or an alkyl glycosides to condition the human skin such that particulate matter, which is deposited onto the skin after the skin is washed with a composition comprising cocamidopropyl betaine and/or an alkyl glycosides, can be rinsed off the skin with water.

2. Use of a composition comprising cocamidopropyl betaine and/or an alkyl glycosides to form a protective layer or protective barrier on the human skin, whereby the protective layer or barrier allows particulate matter, which is deposited onto the skin after application of the composition, to be rinsed off the skin with water.

3. Use according to claim 2 characterized in that the protective layer or protective barrier is formed by applying the composition to the human skin and washing the composition off the skin with water, which happens before the particulate matter is deposited.

4. Use according to any of the proceeding claims characterized in that cocamidopropyl betaine is contained in the composition in a total quantity ranging from 2.0 to 10% by weight, more preferably 2.5 to 8.0% by weight and most preferably 3.0 to 6.0% by weight, calculated to the total weight of the composition.

5. Use according to any of the proceeding claims characterized in that alkyl glycosides are contained in the composition in a total quantity ranging from 0.1 to 10% by weight, more preferably 0.5 to 8.0% by weight and most preferably 1.0 to 6.0% by weight, calculated to the total weight of the composition.

6. Use according to any of the proceeding claims characterized in that the alkyl glycosides are chosen from lauryl glucoside, decyl glucoside and coco glucoside.

7. Use according to any of the proceeding claims characterized in that lauryl glucoside is contained as alkyl glycosides.

8. Use according any proceeding claim characterized in that the compositions comprises water as cosmetic carrier in a proportion of 50% by weight to 98% by weight, preferably 60% by weight to 94% by weight and most preferably from 65% by weight to 95% by weight, based on the total weight of the composition.

9. Use according any proceeding claim characterized in that the composition comprises sodium benzoate and/or sodium salicylate.

10. Use according any proceeding claim characterized in that the composition comprises phenoxyethanol.

11 . Use according any proceeding claim characterized in that the composition is free from polymers polymerized from a mixture comprising acrylic acid and/or methacrylic acid.