Composition, Process For Preparation And Method Of Use

Abstract

Depilatory compositions including a depilatory agent, fatty alcohol and VP/hexadecene copolymer that provide increased resistance to rinsing of the compositions from the skin. The compositions provide for a method of depilation in wet conditions using a tool to apply and remove the compositions.

Claims

1. A depilatory composition comprising: an emulsion of hydrophobic particles in a continuous aqueous phase; wherein the continuous aqueous phase comprises a depilatory agent; and wherein the hydrophobic particles comprise a fatty alcohol and hexadecene copolymer.

2. The depilatory composition of claim 1, wherein the hexadecene copolymer is a VP/hexadecene copolymer having a molecular weight of from about 4,000 to 13,000 mass units.

3. The depilatory composition of claim 1, wherein the hexadecene copolymer is a VP/hexadecene copolymer having a molecular weight in the range 6,500 to 8,500 mass units.

4. The depilatory composition of claim 1, wherein hexadecene copolymer is a polymer with the structure (C.sub.22H.sub.41NO).sub.x.

5. The depilatory composition of claim 1 comprising from 3 to 20% by weight of fatty alcohol and 0.2 to 5% by weight of an oil gelling agent.

6. The depilatory composition of claim 1, wherein the fatty alcohol has an alkyl chain comprising from 8 to 22 carbon atoms.

7. The depilatory composition of claim 1, wherein the depilatory agent is a sulfhydryl compound.

8. The depilatory composition of claim 1 comprising from 1 to 8% by weight of depilatory agent, expressed as the equivalent acid form of the depilatory agent.

9. The depilatory composition of claim 1, wherein the depilatory agent is a sulfhydryl compound; and the inclusion of a hexadecene copolymer and a fatty alcohol in a hydrophobic particle provide adherence qualities of the depilatory composition.

10. The depilatory composition of claim 9, wherein the hexadecene copolymer comprises vinylpyrrolidone/hexadecene copolymer; wherein the vinylpyrrolidone/hexadecene copolymer is in an amount of about 1.9% by weight of the total composition; wherein the vinylpyrrolidone/hexadecene copolymer has a molecular weight in the range of 6,500 to 8,500 mass units; and wherein the vinylpyrrolidone/hexadecene copolymer is a polymer with the structure (C.sub.22H.sub.41NO).sub.x.

11. The depilatory composition of claim 9, wherein the inclusion of a hexadecene copolymer and a fatty alcohol in a hydrophobic particle provide adherence qualities of the depilatory composition to hairy skin such that the depilatory composition has a degradation period greater than three minutes, wherein the degradation period is the time the depilatory composition is left in contact with hairy skin to achieve adequate hair degradation even when rinsed or immersed in water.

12. The depilatory composition of claim 9, wherein the inclusion of a hexadecene copolymer and a fatty alcohol in a hydrophobic particle provide adherence qualities of the depilatory composition to an applied surface such that over 60% of the depilatory composition remains on a surface when subjected to three minutes of running water.

13. The depilatory composition of claim 9, wherein the inclusion of a hexadecene copolymer and a fatty alcohol in a hydrophobic particle provide adherence qualities of the depilatory composition to an applied surface such that over 60% of the depilatory composition remains on a surface when subjected to five minutes of running water.

14. A kit for hair removal comprising: a depilatory tool; and the depilatory composition of claim 1; wherein the depilatory tool comprises a first side arranged to apply a depilatory composition, and a second side arranged to remove a depilatory composition; and wherein the first side and the second side are substantially of a different texture and/or color.

15. The kit of claim 14, wherein the hydrophobic particles of the depilatory composition comprise a fatty alcohol and a VP/hexadecene copolymer is a polymer with the structure (C.sub.22H.sub.41NO).sub.x and has a molecular weight of from 6,500 to 8,500 mass units.

16. The kit of claim 15, wherein the depilatory composition comprises from 3 to 20% by weight of fatty alcohol and 0.2 to 5% by weight of an oil gelling agent; and wherein the fatty alcohol has an alkyl chain having from 16 to 22 carbon atoms.

17. The kit of claim 14, wherein the depilatory agent of the depilatory composition comprises a cosmetically acceptable salt of thioglycolic acid; and wherein the depilatory agent of the depilatory composition comprises from 1 to 8%, by weight of the depilatory composition, expressed as an equivalent acid form of the depilatory agent.

18. The kit of claim 14, wherein the depilatory agent of the depilatory composition is a sulfhydryl compound; and the inclusion of a hexadecene copolymer and a fatty alcohol in a hydrophobic particle provide adherence qualities of the depilatory composition.

19. The kit of claim 18, wherein the hexadecene copolymer of the hydrophobic particles comprises vinylpyrrolidone/hexadecene copolymer; wherein the vinylpyrrolidone/hexadecene copolymer is in an amount of about 1.9% by weight of the total depilatory composition; wherein the vinylpyrrolidone/hexadecene copolymer has a molecular weight in the range of 6,500 to 8,500 mass units; and wherein the vinylpyrrolidone/hexadecene copolymer is a polymer with the structure (C.sub.22H.sub.41NO).sub.x.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0037] The sole FIGURE is a graph of an experimental result for the present invention.

DETAIL DESCRIPTION OF THE INVENTION

[0038] To facilitate an understanding of the principles and features of the various embodiments of the invention, various illustrative embodiments are explained below. Although exemplary embodiments of the invention are explained in detail, it is to be understood that other embodiments are contemplated. Accordingly, it is not intended that the invention is limited in its scope to the details of construction and arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways. Also, in describing the exemplary embodiments, specific terminology will be resorted to for the sake of clarity.

[0039] It should also be noted that, as used in the specification and the appended claims, the singular forms a, an and the include plural references unless the context clearly dictates otherwise. For example, reference to a component is intended also to include composition of a plurality of components. References to a composition containing a constituent is intended to include other constituents in addition to the one named.

[0040] Also, in describing the exemplary embodiments, terminology will be resorted to for the sake of clarity. It is intended that each term contemplates its broadest meaning as understood by those skilled in the art and includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.

[0041] Ranges may be expressed herein as from about or approximately or substantially one particular value and/or to about or approximately or substantially another particular value. When such a range is expressed, other exemplary embodiments include from the one particular value and/or to the other particular value.

[0042] Similarly, as used herein, substantially free of something, or substantially pure, and like characterizations, can include both being at least substantially free of something, or at least substantially pure, and being completely free of something, or completely pure.

[0043] By comprising or containing or including is meant that at least the named compound, element, particle, or method step is present in the composition or article or method, but does not exclude the presence of other compounds, materials, particles, method steps, even if the other such compounds, material, particles, method steps have the same function as what is named.

[0044] It is also to be understood that the mention of one or more method steps does not preclude the presence of additional method steps or intervening method steps between those steps expressly identified. Similarly, it is also to be understood that the mention of one or more components in a composition does not preclude the presence of additional components than those expressly identified.

[0045] The materials described as making up the various elements of the invention are intended to be illustrative and not restrictive. Many suitable materials that would perform the same or a similar function as the materials described herein are intended to be embraced within the scope of the invention. Such other materials not described herein can include, but are not limited to, for example, materials that are developed after the time of the development of the invention.

[0046] In an exemplary embodiment, the invention provides a depilatory composition which is an emulsion of hydrophobic particles in a continuous aqueous phase wherein the aqueous phase comprises at least one depilatory agent and the hydrophobic particles comprise a fatty alcohol and a vinylpyrrolidone (VP) hexadecene copolymer.

[0047] A particularly preferred hexadecene copolymer is a VP/hexadecene copolymer preferably having a molecular weight from about 4000 to 13,000, such as 5000 to 11,000, mass units. A particularly preferred molecular weight is in the range 6,500 to 8,500, such as about 7,300. Such a copolymer provides the advantage of ease of incorporation of the hexadecene into the hydrophobic particles of the invention by melting and blending. A VP hexadecene suitable for use in compositions of the invention is a polymer with the structure (C.sub.22H.sub.41NO).sub.x.

[0048] The depilatory agent is a substance capable of degrading keratin. The depilatory agent, according to the present invention, may include a mixture of one or more depilatory agents. Preferred depilatory agents are sulfhydryl compounds, meaning a compound having an SH group. Suitable sulfhydryl depilatory agents include but are not limited to the group consisting of thioglycolic acid, cysteine, homocysteine, glutathione, thioglycerol, thiomalic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiodiglycol, 2-mercaptoethanol, dithiothreitol, thioxanthene, thiosalicylic acid, thiolactic acid, thiopropionic acid, thiodiglycolic acid, N-acetyl-L-cysteine, lipoic acid, and cosmetically- and/or pharmaceutically acceptable salts of any of the foregoing compounds.

[0049] Preferred sulfhydryl compounds include thioglycolic acid, cysteine, glutathione, N-acetyl-L-cysteine, lipoic acid, thiosalicylic acid, and thiolactic acid and cosmetically- and/or pharmaceutically-acceptable salts thereof. More preferred sulfhydryl compounds include thioglycolic acid, cysteine, glutathione and N-acetyl-L-cysteine and cosmetically- and/or pharmaceutically acceptable salts thereof. A preferred sulfhydryl compound is thioglycolic acid and cosmetically- and/or pharmaceutically-acceptable salts thereof. As used herein, cosmetically- and/or pharmaceutically-acceptable salts of the sulfhydryl compounds include, but are not limited to alkali metal salts, e.g., sodium, lithium, rubidium and potassium salts; alkaline earth metal salts, e.g., magnesium, calcium and strontium salts; non-toxic heavy metal salts, e.g., aluminum salts and zinc salts; boron salts; silicon salts; ammonium salts; trialkylammonium salts, e.g., trimethylammonium and triethylammonium; and tetralkylonium salts.

[0050] Preferred cosmetically- and/or pharmaceutically-acceptable salts of the sulfhydryl compound include sodium, potassium and calcium salts. Preferred salts of the sulfhydryl compound are potassium and calcium salts.

[0051] Suitably, the composition comprises from 1 to 8% by weight, preferably from 2 to 6% by weight, of depilatory agent expressed as the acid form of the depilatory agent. For example, it is preferred that the composition comprises potassium glycolate at pH 12.3, this is not expressed as potassium thioglycolate, but as the equivalent weight of thioglycolic acid.

[0052] Optionally, the composition includes an accelerator that will accelerate the keratin degradation reaction. Suitable accelerators include urea, thiourea, dimethyl isosorbide, ethoxydiglycol and methyl propyl diol. Preferably the accelerator is urea or methyl propyl diol. The composition according to the invention preferably comprises from 5% to 15% by weight, more preferably 7% to 10% by weight of an accelerator.

[0053] It is particularly preferred for the composition to comprise a pH regulator to assist in activating the depilatory agent, particularly when the depilatory agent is a sulfhydryl compound. Preferably the quantity and type of pH regulator is chosen to maintain the pH of the composition at a value greater than 5, preferably greater than 7, more preferably from 8 to 13, more preferably from 10 to 12.9, especially from 12 to 12.7.

[0054] For example, by ensuring that the pH is about 12.1 to 12.7, depilation can occur within about five minutes, as desired by the user, without causing undue irritation. Higher pH levels can lead to irritation problems with some users.

[0055] The pH regulator preferably is in the continuous aqueous phase (between the hydrophobic particles) when present. Examples of the pH regulator include arginine (especially L-arginine), silicates (e.g. sodium or potassium silicate), calcium hydroxide and polyethyleneimine. Mixtures of pH regulators may be used. It is particularly preferred for the pH regulator also to include calcium hydroxide in an amount from 2 to 4% by weight of the composition. The pH regulator may be dissolved in the aqueous phase of the composition or may be present as solid particles dispersed throughout the composition.

[0056] Compositions according to the invention comprise hydrophobic particles distributed as an emulsion (an oil-in-water emulsion) in an aqueous continuous phase which is a liquid at 25 C. By aqueous it is meant that the continuous phase comprises at least 50% by weight of water, preferably 70% by weight or more based on the total weight of the continuous phase. The amount of water in the composition as a whole will typically be from 40% to 95% by weight of the composition.

[0057] The hydrophobic particles of the compositions of the invention may comprise non-polar oily or waxy materials which are insoluble in water (by insoluble is meant a solubility in water of 0.1% by weight or less at 25 C.) but should comprise a fatty alcohol. Preferably, the alkyl/alkenyl chain of the fatty material is fully saturated. Suitable fatty alcohols comprise from 8 to 22 carbon atoms, more preferably 16 to 22. A mixture of fatty alcohols may also be used. Preferred fatty alcohols include cetyl alcohol, stearyl alcohol and mixtures thereof.

[0058] Suitably, the amount of fatty alcohol in compositions of the invention is 3% or more, preferably 5% or more, more preferably 7% or more by weight of the composition. Suitably, compositions of the invention comprise less than 20%, preferably less than 15%, more preferably less than 11% by weight of fatty alcohol.

[0059] The hydrophobic particles of the composition further comprise an oil gelling agent. Suitable oil gelling agents include waxes having a melting point from 65 C. to 130 C., polymeric gelling agents and mixtures thereof. Compositions of the invention suitably comprise from 0.2 to 5%, preferably from 0.5 to 4% more preferably from 1 to 3% by weight of the oil gelling agent.

[0060] Suitable waxes include beeswax, carnauba, baysberry, candelilla, montan, ozokerite, ceresin, hydrogenated castor oil (castor wax), synthetic waxes such as Fisher-Tropsch waxes, microcrystalline waxes, and mixtures thereof. Waxes such as triglycerides or glycol diesters of C.sub.18 to C.sub.36 fatty acids are also suitable as gelling agent for the oil phase.

[0061] Particles means finely divided parts, and encompasses solid particles, liquid particles and plastic or waxy particles. Preferably, the particles are solid at a temperature of 25 C. or less. Preferably, the particles are liquid at a temperature of 80 C. or more in order to facilitate the preparation of the composition. The hydrophobic particles suitably have a mean diameter D.sub.4,.sub.3 as measured by laser light scattering (using apparatus such as a Malvern Mastersizer) from 0.1 to 50 micrometers, preferably from 0.5 to 20 micrometers, more preferably from 1 to 10 micrometers.

[0062] Preferably, compositions of the invention include an emulsifier to facilitate the emulsification of the hydrophobic particles in the continuous aqueous phase and to stabilize the emulsion against coalescence of the hydrophobic particles. In general the emulsifier is an anionic, cationic, non-ionic or zwitterionic surfactant. Preferably the emulsifier is a non-ionic surfactant. Suitable nonionic surfactants include alkyl ethers of polyethylene glycol and/or polypropylene glycol, including mixed ethers and mixtures thereof. The emulsifier is suitably present in an amount of from 2% to 10%, more preferably from 3% to 8% by weight of the composition.

[0063] The compositions of the invention, in addition to the hydrophobic particles and the aqueous continuous liquid phase, may also include other ingredients that are conventionally present in depilatory formulations, such as perfumes, oils, and pigments (such as titanium dioxide) and thickeners such as a clay.

[0064] Suitable clays for thickening may include organophilic and layered clay minerals belonging to the geological classes of the smectites, the kaolins, the illites, the chlorites, the attapulgites and the mixed layer clays. Typical examples of specific clays belonging to these classes are: 1) smectites, e.g. montmorillonite, bentonite, pyrophyllite, hectorite, saponite, sauconite, nontronite, talc, beidellite; 2) illites, e.g., bravaisite, muscovite, paragonite, phlogopite; 3) chlorites, e.g., corrensite, penninite, donbassite, sudoite; 4) attapulgites, e.g., sepiolite, and polygorskyte.

[0065] The layered clay minerals may be either naturally occurring or synthetic. Preferred clay minerals for use in the present invention are natural or synthetic smectites and attapulgites, (particularly the hectorites, montmorillonites and bentonites,) and of these the hectorites are especially preferred. Many of the above clays are available commercially, and typical examples of commercial hectorites are the Laponites ex Laporte Industries Ltd., England; Veegum Pro and Veegum F ex R. T. Vanderbilt, USA; and the Barasyms, Macaloids and Propaloids ex Baroid Division, National Lead Company, USA. If a clay is used for thickening, it is preferably in an amount of from 0.1 to 10% by weight, more preferably from 0.1 to 1% by weight of the composition.

[0066] The inclusion of a clay, preferably sodium lithium magnesium silicate, is particularly advantageous, since this provides lithium, sodium and magnesium ions for the buffer system and improves the efficiency of depilation. It is particularly preferred if the clay is a synthetic hectorite clay such as laponite.

[0067] Other optional water-soluble thickening agents which may be used include Carbomer (Acrylic acid polymer, preferably cross-linked), acrylic polymer emulsions (e.g. acrylate/steareth-20 methracylate copolymer), polysaccharides, cellulose based thickeners or natural thickeners such as gum arabic, alginates, carrageenan, locust bean gum, xanthan gum and polyvinyl alcohol. Mixtures of thickeners may be used.

[0068] A suitable method for preparing compositions according to the invention comprises the following steps:

[0069] blending the fatty alcohol, emulsifier and oil gelling agent together into a molten phase at a temperature of 60, preferably 70 C. or more,

[0070] emulsifying the molten phase into an aqueous phase, the temperature of the aqueous phase prior to emulsification being 50 C., preferably 60 C., more preferably 70 C. or more, whereby an emulsion comprising dispersed hydrophobic particles is formed,

[0071] cooling the emulsion to a temperature of 40 C. or less, and

[0072] dispersing the depilatory agent and at least a portion of any accelerator in the emulsion.

[0073] The depilatory agent and any portion of any optional accelerator are preferably not added until after the emulsion has been cooled to prevent degradation of the depilatory agent (which may occur at substantially elevated temperatures). Any optional ingredients may be added thereafter; however it is preferred for at least a portion of any clay to be added at an elevated temperature.

[0074] In an alternative process according to the invention, the temperature of the aqueous phase may be below 40 C., preferably below 25 C. prior to emulsification whereby the temperature of the resulting emulsion, comprising dispersed particles, has a temperature of 40 C. or less, whereby no further cooling step is required prior to dispersing the depilatory agent and at least a portion of any accelerator in the emulsion. Alternatively, the depilatory agent and at least a portion of any optional accelerator may be present in the aqueous phase prior to the addition of the molten phase to the aqueous phase.

[0075] The second aspect of the invention provides a method of hair removal from human skin including the steps of

[0076] applying a composition according to the first aspect of the invention to the skin where superfluous hair is present,

[0077] allowing the composition to remain in contact with the skin for a predetermined time,

[0078] removing the composition and degraded hair using a removal tool, and

[0079] preferably washing the skin,

[0080] For this second aspect of the invention, it is preferred if the composition is applied to the skin with an application tool, giving the advantage that the composition does not come into contact with the users hands. A block of material such as a sponge or a spatula may be employed, but a preferred application tool is a glove, mitt or thumbless mitt, preferably furnished with an inner layer or membrane which is impermeable to the composition. Preferably, the membrane is also impermeable to water.

[0081] The composition and degraded hair are preferably removed from the skin using a removal tool. A block of material such as a sponge or a spatula may be employed, but a preferred application tool is a glove, mitt or thumbless mitt, preferably furnished with an inner layer or membrane which is impermeable to the composition. Preferably, the membrane is also impermeable to water.

[0082] It is particularly advantageous if the application tool and removal tool are provided as a combined tool which has two distinct sides, i.e. front and back, which are distinguishable by the user, one side being adapted to apply the composition to the skin, and the other side being adapted to remove the composition from the skin. This has the advantage that only a single combined tool is needed for the application and removal while minimizing or preventing contact of the users hands with the composition and preventing accidental transfer of the composition to other parts of the body while ablutions are being performed. Preferably the front and back faces of the tool are of distinctly different texture and/or color.

[0083] Preferably the tool is a mitt or glove, more preferably a thumbless mitt, comprising an inner layer of a first material and an outer layer of a second material with an impermeable layer of flexible polymer membrane sandwiched between the inner and outer layers. Preferably the front and back faces of the tool are of distinctly different texture and/or color. A thumbless mitt has the advantage that the user can apply the composition with the mitt on one hand, using the application side, then use the same mitt on the same hand for removal, using the removal side.

[0084] In an alternative embodiment, the tool may be in the form of a block of material, such as a rectangular parallelipiped or an ellipsoidal shape suitable to be held in the hand.

[0085] Preferably the block is formed of two portions which are joined together, wherein one portion is adapted for application of the composition of the invention, and preferably is non-porous, and the other portion is adapted for removal of the composition and degraded hair, and is preferably porous and more preferably spongy and is even more preferably furnished with a textured surface suitable for massaging or exfoliating the skin. Preferably the portion adapted for application of the composition is substantially impermeable to water and to the composition.

[0086] Therefore, according to yet a further aspect of the present invention, there is provided a depilatory tool having a first side arranged to apply a depilatory composition, and a second side arranged to remove a depilatory composition, wherein the first side and the second side are substantially of a different texture and/or color.

[0087] Advantageously, the first side and/or the second side are in of cellular material such as a foam or sponge-like material. The sponge may be a natural sponge or a synthetic sponge. It is envisaged that the second side is more coarse or abrasive then the first side thereby assisting in the removal of the depilatory cream together with the degraded hair.

[0088] According to the invention there is further provided the use of a composition according to the invention to degrade hair keratin.

[0089] Throughout this specification, percentages of ingredients by weight are referenced to the weight of the total composition, unless otherwise specified. The following Examples illustrate the invention.

[0090] A composition was prepared according to the formulation given in table 1 by emulsifying a melt at 70 C. formed from the cetearyl alcohol, ceteareth 20, ppg-15 stearyl ether paraffin wax and VP hexadecene copolymer. The resulting blend was cooled to 40 C. prior to addition of the depilatory agent: other ingredients were blended while cooling from 70 to 40 C.

[0091] The resultant composition was applied to an area of skin having superfluous hair thereon, a prior art depilatory formulation was applied to a similar sized area of skin having superfluous hair thereon. The % of depilatory cream left on the skin after 3, 4, 5 and 6 minutes under a stream of water from a shower head is given in the form of a graph in the sole FIGURE, wherein the graph represents the % of cream remaining on the skin during the test.

[0092] The resultant composition demonstrated improved reduced rinsability when compared to prior art depilatory compositions.

TABLE-US-00001 TABLE 1 Ingredient % Ceteareth 20 (Emulgin B2) 3.0 Cetearyl Alcohol 30/70 8.0 PPG - 15 Stearyl Ether (Arlamol E) 2.55 VP/Hexadecene Copolymer 1.9 Paraffin Wax 5.2 Urea 7.5 Ca Hydroxide 4.00 Na Gluconate 0.1 Mg Trisilicate 0.75 Premix Pink Paste 0.5 Lotus Flower Milk 0.15 Acrylate Copolymers 0.15 Potassium Thioglycolate Premix 12.0 Thelma 200 0.6 Spray Dried Silica 0.05 KOH 50% Solution 1 Deionized Water 52.55

[0093] Numerous characteristics and advantages have been set forth in the foregoing description, together with details of structure and function. While the invention has been disclosed in several forms, it will be apparent to those skilled in the art that many modifications, additions, and deletions, especially in matters of shape, size, and arrangement of parts, can be made therein without departing from the spirit and scope of the invention and its equivalents as set forth in the following claims. Therefore, other modifications or embodiments as may be suggested by the teachings herein are particularly reserved as they fall within the breadth and scope of the claims here appended.