Skin cleansing composition

Abstract

The present invention discloses a skin cleansing composition comprising an anionic surfactant selected from alkyl sulfate, alkyl ether sulfate or a mixture thereof; polypropylene glycol; and glycol; wherein the weight ratio of glycol to anionic surfactant is at least 1:5.

Description

Technical Field

[0001] The present invention relates to a skin cleansing composition suitable for an automatic dispensing device. In particular, such a composition can generate fine, uniform and stable foam by the automatic dispensing device after being stored at high and low temperatures, and leave less residue at high temperatures. Background Art

[0002] Due to their convenience and contactless nature, automatic dispensing devices have been widely used to provide skin cleansing compositions in many settings, such as airports, hotels, and homes. Ambient temperatures can vary significantly depending on the region and / or location. Such temperatures can affect the performance of skin cleansing compositions in automatic dispensing devices. The present inventors have discovered that certain issues exist, such as a lack of smooth and dense foam produced after storage at low temperatures, and increased residue around the device's nozzle at high temperatures, increasing the risk of nozzle clogging.

[0003] The present inventors recognized the need to develop skin cleansing compositions that are broadly adaptable to different temperatures. Thus, they can provide consumers with a good cleansing experience at low temperatures while producing less residue at high temperatures. Surprisingly, they discovered that by including polypropylene glycol and glycol in a skin cleansing composition containing an anionic surfactant at a specific weight ratio of glycol to anionic surfactant, the composition can produce a smooth, uniform, and stable foam after storage at both high and low temperatures using an automatic dispensing device, while leaving less residue at high temperatures. Summary of the Invention

[0004] In a first aspect, the present invention relates to a skin cleansing composition comprising an anionic surfactant selected from alkyl sulfates, alkyl ether sulfates or mixtures thereof; polypropylene glycol and a glycol, wherein the weight ratio of the glycol to the anionic surfactant is at least 1:5.

[0005]

[0011] All further aspects of the invention will become more apparent upon consideration of the following detailed description and examples. DETAILED DESCRIPTION

[0006] Except in the examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or reaction conditions, physical properties of materials and / or use may optionally be understood as modified by the word "about."

[0007] All amounts are by weight of the composition unless otherwise indicated.

[0008] It should be noted that when specifying any range of values, any particular upper value can be associated with any particular lower value.

[0009] For the avoidance of doubt, the word "comprising" is intended to mean "including" but not necessarily "consisting of" or "composed of." In other words, the listed steps or options need not be exhaustive.

[0010] The disclosure of the invention provided herein is deemed to cover all embodiments as presented in the claims that are multiply dependent on each other, irrespective of the fact that the claims may not have multiply dependence or redundancy.

[0011] Where a feature is disclosed with respect to a particular aspect of the invention (eg, a composition of the invention), such disclosure is also considered applicable, mutatis mutandis, to any other aspect of the invention (eg, a method of the invention).

[0012] The anionic surfactants suitable for use in the present invention are selected from alkyl sulfates (i.e., sulfates), alkyl ether sulfates, or mixtures thereof. Preferably, the alkyl sulfates and alkyl ether sulfates have the corresponding formulas R1OSO3M and R1O(C2H4O) x SO3M, wherein each R1 is an alkyl or alkenyl group having 8 to 18 carbon atoms, x is an integer having a value of 1 to 10, and each M is a cation such as ammonium, an alkanolamine such as triethanolamine, a monovalent metal such as sodium and potassium, and a polyvalent metal cation such as magnesium and calcium. More preferably, each R1 is an alkyl or alkenyl group having 10 to 16 carbon atoms, x is an integer having a value of 1 to 10, and each M is a cation of triethanolamine, sodium or potassium. Most preferably, each R1 and R2 has 12 to 14 carbon atoms and is a straight chain rather than a branched chain.

[0013] Typically, the anionic surfactant is selected from sodium lauryl sulfate and sodium lauryl ether sulfate, sodium trideceth sulfate, ammonium lauryl sulfate, lauryl ethylammonium sulfate, or mixtures thereof. Preferred anionic surfactants are selected from sodium lauryl sulfate and sodium lauryl ether sulfate (n) EO, (wherein n is 1 to 3); more preferably sodium lauryl ether sulfate (n) EO, (wherein n is 1 to 3); most preferably sodium lauryl ether sulfate (n) EO, where n=1.

[0014] Preferably, the total amount of alkyl sulphate and alkyl ether sulphate is from 1% to 25%, more preferably from 2% to 20%, even more preferably from 4% to 16% and still even more preferably from 6% to 14% by weight of the composition.

[0015] Preferably, the polypropylene glycol comprises 2 to 200, more preferably 3 to 50, even more preferably 4 to 20 polymerized propylene oxide units. Preferably, the polypropylene glycol has a number average molecular weight of 100 to 50,000, more preferably 200 to 5,000. Most preferably, the polypropylene glycol is polypropylene glycol-7 (PPG-7).

[0016] Preferably, the polypropylene glycol is present in an amount of 0.1 to 10%, more preferably 0.5 to 7%, more preferably 1 to 4% by weight of the composition.

[0017] As used herein, diol refers to an alcohol having two hydroxyl groups. Preferably, the diol has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, and most preferably, the diol has 3 to 4 carbon atoms.

[0018] Particularly preferred glycols include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, isoprene glycol, hexylene glycol, or a mixture thereof. More preferably, the glycol includes ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, or a mixture thereof. Even more preferably, the glycol includes propylene glycol, butylene glycol, or a mixture thereof. Even more preferably, the glycol includes propylene glycol, and most preferably, the glycol is propylene glycol. For clarity, glycol is chemically different from polypropylene glycol.

[0019] Typically, the amount of diol is 0.1-30 wt%, preferably 0.5-20 wt%, more preferably 1-15 wt%, even more preferably 2-10 wt%, based on the total weight of the composition.

[0020] In order to obtain better foaming properties and / or sensory properties, the weight ratio of glycol to the total amount of alkyl sulfate and alkyl ether sulfate is preferably 1:5 to 50:1, more preferably 1:5 to 5:1, even more preferably 1:4 to 2: 1. In order to obtain better foaming properties and / or sensory properties, the weight ratio of polypropylene glycol to the total amount of alkyl sulfate and alkyl ether sulfate is preferably 1:50 to 10:1, more preferably 1:20 to 5:1, even more preferably 1:10 to 2:1, and still even more preferably 1:8 to 1:1.

[0021] The composition may further comprise a monomeric alcohol. As used herein, a monomeric alcohol refers to an alcohol that is not a polymer. Monomeric alcohols are chemically different from glycols and polypropylene glycols. Preferably, the monomeric alcohol comprises glycerol (i.e., glycerol or glycerine), sorbitol, hydroxypropyl sorbitol, 1,2,6-hexanetriol, ethoxylated glycerol, propoxylated glycerol, or a mixture thereof. More preferably, it comprises glycerol, sorbitol, or a mixture thereof. Even more preferably, the monomeric alcohol comprises glycerol, and most preferably, the monomeric alcohol is glycerol. Preferably, the monomeric alcohol has a molecular weight of 50 to 500, more preferably 60 to 300.

[0022] Preferably, the amount of monomeric alcohol is 0.1-30 wt%, preferably 1-20 wt%, more preferably 3-15 wt%, even more preferably 5-10 wt%, based on the total weight of the composition.

[0023] Preferably, the total amount of monomeric alcohols and diols is 0.1-40 wt %, preferably 1-20 wt %, more preferably 3-15 wt %, even more preferably 6-12 wt %, based on the total weight of the composition. Preferably, the weight ratio of the total weight of monomeric alcohols and diols to the total weight of alkyl sulfate and alkyl ether sulfate is in the range of 1:10 to 10:1, more preferably in the range of 1:6 to 6:1, even more preferably in the range of 1:2 to 2:1, to achieve better foaming and / or sensory properties.

[0024] The composition may additionally comprise an amphoteric surfactant.The amount of the amphoteric surfactant may range from 0.5 to 8%, preferably from 1 to 4% by weight of the total composition.

[0025] Examples of amphoteric surfactants include alkylamine oxides, alkyl betaines, alkylamidopropyl betaines, alkyl sulfobetaines (sulfobetaines), alkyl glycinates, alkyl carboxyglycinates, alkyl amphoacetates, alkyl amphopropionates, alkyl amphoglycinates, alkylamidopropyl hydroxysulfobetaines and / or acyltaurates and acylglutamates, wherein the alkyl and acyl groups have 8-19 carbon atoms. Typical amphoteric surfactants for the compositions of the present invention include laurylamine oxide, cocodimethyl sulfopropyl betaine, lauryl betaine, cocamidopropyl betaine and / or sodium cocoamphoacetate. A particularly preferred amphoteric surfactant is cocamidopropyl betaine.

[0026] Water-insoluble skin benefit agents can also be formulated into the composition as conditioning agents and moisturizers. Examples include silicone oils; hydrocarbons such as liquid paraffin, petrolatum, microcrystalline wax, and mineral oil; and vegetable triglycerides such as sunflower oil and cottonseed oil.

[0027] Some compositions can include thickeners. These can be selected from celluloses, natural gums and acrylic polymers, but are not limited to these thickener types. Cellulose includes sodium carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methylcellulose and combinations thereof. Suitable gums include xanthan gum, pectin, karaya gum, agar, alginate gum and combinations thereof. Acrylic thickeners include homopolymers and copolymers of acrylic acid and methacrylic acid, including carbomers, such as Carbopol 1382, Carbopol 982, Ultrez, Aqua SF-1 and Aqua SF-2, available from Lubrizol. The amount of thickener can be in the range of 0.01-3% by weight of the active polymer (outside solvent or water) in the composition.

[0028] Preservatives may be desirably incorporated into the compositions of the present invention to prevent the growth of potentially harmful microorganisms. Traditional preservatives suitable for use in the compositions of the present invention are alkyl esters of parahydroxybenzoic acid. Other preservatives that have recently come into use include hydantoin derivatives, propionates, and various quaternary ammonium compounds. Particularly preferred preservatives are phenoxyethanol, methylparaben, propylparaben, imidazolidinyl urea, sodium dehydroacetate, and benzyl alcohol. The preservative should be selected taking into account the intended use of the composition and any potential incompatibilities between the preservative and other ingredients. The preservative is preferably used in an amount ranging from 0.01% to 2% by weight of the composition.

[0029] A variety of other optional materials may be formulated into the composition. These may include: antimicrobial agents such as 2-hydroxy-4,2',4'-trichlorodiphenyl ether (triclosan), 2,6-dimethyl-4-hydroxychlorobenzene, and 3,4,4'-trichlorocarbonanilide; scrubbing and exfoliating particles, such as polyethylene and silica or alumina; cooling agents such as menthol; skin calming agents such as aloe vera; and coloring agents.

[0030] In addition, the composition of the present invention may further comprise 0.05 to 10% by weight of a chelating agent, such as tetrasodium ethylenediaminetetraacetic acid (EDTA), EHDP, or a mixture; opacifiers and pearlescent agents, such as ethylene glycol distearate, titanium dioxide, or Lytron 621 (styrene / acrylate copolymer); all of which may be used to enhance the appearance or performance of the product.

[0031] The composition may comprise water in an amount of 10-95%, more preferably 20-88%, even more preferably 35-82%, most preferably 45-75% by weight of the composition.

[0032] Preferably, when heated at 20°C for about 20 seconds -1 The composition has a viscosity of at least 5 mPa·s, more preferably in the range of 8 to 10,000 mPa·s, even more preferably 10 to 1,000 mPa·s, and most preferably 20 to 200 mPa·s when measured at a relatively high shear rate of 10000 mPa·s. Preferably, the composition is in fluid form.

[0033] Skin cleansing compositions (products) refer to compositions (products) suitable for topical application to human skin, preferably rinse-off products. The term "rinse-off" as used herein with respect to the compositions herein refers to compositions that are applied to the skin or rubbed on the skin and then washed off. The term "skin" as used herein includes the skin on the face (excluding the eyelids and lips), neck, chest, abdomen, back, arms, underarms, hands, and legs. Preferably, "skin" refers to the skin including the face (excluding the eyelids and lips) and underarms, and more preferably, skin refers to the skin on the face excluding the lips and eyelids.

[0034] The following examples are provided to facilitate understanding of the present invention. The examples are not intended to limit the scope of the claims.

[0035] Example

[0036] Example 1

[0037] This example illustrates the effect of propylene glycol and glycol on foaming performance.

[0038] Table 1

[0039]

[0040] *Ingredient levels refer to active substance levels.

[0041] A series of skin cleansing compositions were formulated according to Table 1 by following the standard procedure.

[0042] All samples were evaluated for their low-temperature foaming performance using the following procedure. Each sample was placed in the same automated dosing device and stored at 5°C for 15 days. The same amount of sample was then pumped from the device onto a watch glass. The foam was observed and evaluated based on its richness and fineness. Foam with a high number of large bubbles was labeled "Unacceptable," fine and dense foam was labeled "Good," and intermediate foam was labeled "Acceptable."

[0043] The samples' performance at high temperatures was evaluated using the following procedure. Each sample was placed into an identical automated dosing device. The sample was pumped from the device into a glass beaker, filling the beaker with foam. The glass beakers containing the samples were then placed in a 50°C oven for 7 hours. The beakers were then removed and observed. Samples with significant residue on the beaker walls were marked "unacceptable," samples with no visible residue on the beaker walls were marked "good," and intermediate samples were marked "acceptable."

[0044] The properties of all samples are reported in Table 2.

[0045] Table 2

[0046]

[0047] X: unacceptable; √: acceptable; √√: good

[0048] Surprisingly, it has been discovered that by including polypropylene glycol and glycol in a specific weight ratio of glycol to anionic surfactant into a skin cleansing composition containing anionic surfactant, the composition is capable of producing a fine, uniform, and stable foam by an automatic dispensing device (even after storage at low temperatures), and leaving much less residue at high temperatures.

Claims

1. A skin cleansing composition comprising: (a) an anionic surfactant selected from alkyl sulfates, alkyl ether sulfates, or mixtures thereof, wherein the total amount of the alkyl sulfates and the alkyl ether sulfates is from 1% to 25% by weight of the composition; (b) polypropylene glycol, wherein the polypropylene glycol is present in an amount of 0.1% to 10% by weight of the composition; and (c) a diol, wherein the diol comprises ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, or a mixture thereof, wherein the amount of the diol is from 0.1 wt % to 30 wt % of the total weight of the composition; wherein the weight ratio of the diol to the anionic surfactant is at least 1:

5.

2. A composition according to claim 1 wherein the total amount of said alkyl sulfate and said alkyl ether sulfate is from 4% to 16% by weight of the composition.

3. The composition according to claim 1 or 2, wherein the anionic surfactant is selected from sodium lauryl sulfate and sodium lauryl ether sulfate, sodium trideceth sulfate, ammonium lauryl sulfate, lauryl ethylammonium sulfate or mixtures thereof.

4. The composition according to claim 1 or 2, wherein the polypropylene glycol is polypropylene glycol-7.

5. The composition of claim 1 or 2, wherein the polypropylene glycol is present in an amount of 1% to 4% by weight of the composition.

6. The composition of claim 1 or 2, wherein the glycol comprises propylene glycol.

7. The composition according to claim 1 or 2, wherein the amount of the diol is 1 to 15 wt% based on the total weight of the composition.

8. The composition according to claim 1 or 2, wherein the weight ratio of the glycol to the total amount of the alkyl sulfate and the alkyl ether sulfate is from 1:5 to 50:

1.

9. The composition according to claim 1 or 2, wherein the weight ratio of the glycol to the total amount of the alkyl sulfate and the alkyl ether sulfate is from 1:4 to 2:

1.

10. The composition according to claim 1 or 2, wherein the weight ratio of the polypropylene glycol to the total amount of the alkyl sulfate and the alkyl ether sulfate is 1:50 to 10:

1.

11. The composition according to claim 1 or 2, wherein the weight ratio of the polypropylene glycol to the total amount of the alkyl sulfate and the alkyl ether sulfate is 1:10 to 2:

1.

12. The composition of claim 1 or 2, wherein the composition further comprises a monomeric alcohol.

13. The composition of claim 12, wherein the monomeric alcohol is glycerol.

14. The composition of claim 12, wherein the weight ratio of the total weight of the monomeric alcohol and the diol to the total weight of the alkyl sulfate and the alkyl ether sulfate is in the range of 1:10 to 10:

1.

15. The composition of claim 12, wherein the weight ratio of the total weight of the monomeric alcohol and the diol to the total weight of the alkyl sulfate and the alkyl ether sulfate is in the range of 1:2 to 2:

1.

16. The composition of claim 12, wherein the total amount of the monomeric alcohol and the diol is 0.1-40 wt% based on the total weight of the composition.

17. The composition of claim 12, wherein the total amount of the monomeric alcohol and the diol is 3-15 wt% based on the total weight of the composition.

18. The composition of claim 1 or 2, wherein the composition comprises an amphoteric surfactant.

19. The composition of claim 18, wherein the amphoteric surfactant is cocamidopropyl betaine.

20. The composition of claim 18, wherein the amount of the amphoteric surfactant is 0.5-8% by weight of the total composition.

21. The composition of claim 1 or 2, wherein the composition comprises from 35% to 82% water, by weight of the composition.

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