Self-heating non-aerosol shave product

ES 2 399 896 T3

DESCRIPTION

Self-heating non-aerosol type shaving product

Technical field

The present invention relates to self-heating non-aerosol type shaving cream products.

Background

At present, a well-known form of shaving preparation is the type known as a non-aerosol type shaving gel. Such compositions generally take the form of an oil / water emulsion in which the aqueous phase comprises a water dispersible soap or modified soap-like component. The product is dispensed as a smooth cream that may be non-foaming or that can be foamed by the user through fragmentation.

The user of wet razors generally feels a sensation of heat on their skin while shaving. The heat feels pleasant and also hydrates the user's skin and softens the beard, allowing for a more comfortable shave. Various attempts have been made to provide a sensation of warmth during shaving. For example, soap-based shaving creams have been formulated that react exothermically upon release from the shaving product canister such that the cream imparts heat to the skin, for example, as described in US-3,341. 418. US 3,772,203; US-3,819,524; US-3,866,800; and US-3,878,118. In GB-1110557 it refers to methods of producing hot foam by decomposing hydrogen peroxide.

Summary

The invention features a self-heating non-aerosol type shaving cream product according to any of the claims, including a container with two individual chambers, one of which contains an oxidizing component, the other containing a reducing component. The container also has at least one opening for dispensing the contents of the chambers. The oxidizing component includes a first shaving cream base and an oxidizing agent, and the reducing component includes a second shaving cream base and a reducing agent. Each of the shaving cream bases independently of one another contains an oil / water emulsion including water and a water dispersible surfactant comprising a nonionic surfactant. Preferably, one or two of the shaving cream bases include a thickener, which helps stabilize the viscosity. The amount and proportion of the oxidizing agent and reducing agent are selected to provide an exothermic reaction with a desirable heat profile upon mixing of the oxidizing component and reducing component during use of the non-aerosol shaving product. Since it is a non-aerosol type product, it does not include any propellants or volatile foaming agents.

Both shaving cream bases are virtually soap and ionic surfactant (eg, anionic surfactant) free. By "practically free" is meant that the shaving cream base contains less than 2% soap and anionic surfactant, preferably less than 1.5% soap and ionic surfactant, more preferably less than 1% soap and ionic surfactant. and most preferably 0% soap and ionic surfactant.

The practically soap-free non-ionic formulation is compatible with the active principles used to generate the sensation of heat and is stable in their presence. Non-ionic shaving cream base can also offer other benefits, such as alleviating the problems associated with soap-based products. The nonionic surfactant can include a mixture of two surfactants, with one surfactant being more hydrophobic than the other. Typically, the surfactant mixture may include ethoxylated fatty alcohols having relatively long and relatively short polyethylene oxide chains (polyoxyethylene chains). For example, the mixture may include an ethoxylated fatty alcohol of 2 to 20 ethoxy groups and an ethoxylated fatty alcohol of 21 to 100 ethoxy groups in a ratio in the range of 2.5: 1 to 1: 2.5.

The first shaving cream base and the second shaving cream base are preferably practically identical, which means that each shaving cream base has at least three, preferably at least four, ingredients identical to those of the other. shaving cream base and most preferably these ingredients are present in approximately the same proportion as in the other shaving cream base.

Some applications may have one or more of the following advantages: Shaving products provide a pleasant and warm sensation to the user before and during shaving, in addition to the aesthetic properties of a shaving cream. The warming effect of shaving products helps to accelerate the hydration of the wearer's hair (e.g. beard) and prepare the hair for shaving, improving the

ES 2 399 896 T3 user comfort. Shaving products are dispensed from the packaging in an aesthetic and attractive manner. After application to the user's skin (eg, the user's face), the shaving product remains on the skin during shaving (eg, the cream does not run off the face), even when the shaving product heats up due to an exothermic reaction. Shaving product helps soften hair (eg. g., beard hair) and protects the skin during shaving. The shaving product remains creamy and stable when the shaving product is heated. Shaving products provide desirable performance properties such as lubricity and skin safety, which are maintained during and after heating. The chemistry of the heating system used to heat the shaving products is safe to use on the skin and does not irritate the skin. After shaving, the shaving product can be removed from the skin relatively easily.

Other features and advantages of the invention will be apparent from the description and from the claims.

Detailed description

As used in this form, all percentages are by weight of solid (unless otherwise indicated).

The shaving cream composition is divided into two separate components, (a) an oxidizing component containing a first shaving cream base and the oxidizing agent, and (b) a reducing component containing a second shaving cream base. shaving and reducing agent. Any ingredient that can be easily oxidized by the oxidizing agent during the shelf life of the product is included in the reducing component. These two components are kept separate in the packaging of the shaving cream composition, as will be discussed in more detail below, and are mixed during or after dispensing. When the two components are mixed, an exothermic reaction occurs which heats the shaving cream composition. If the exothermic reaction generates an acid that may tend to irritate the skin of the user, then a component (preferably the reducing component) generally includes a neutralizing agent to neutralize this acid.

A preferred shaving cream base for use in the present invention includes water and a water dispersible surfactant comprising a nonionic surfactant. Preferably, the water dispersible surfactant consists substantially of a nonionic surfactant. Preferably, the nonionic surfactant includes a mixture of nonionic surfactants, more preferably a mixture of a relatively hydrophobic nonionic surfactant and a relatively hydrophilic nonionic surfactant. A more preferred shaving cream base includes, in addition to the ingredients mentioned above, one, or more (or, in a more preferred embodiment, all) of the following optional ingredients: a fatty alcohol, an emollient (e.g. g., an oil), and a thickener. The shaving cream base is typically in the form of an oil / water emulsion.

The water dispersible surfactant, which is preferably a mixture of surfactants, is selected to provide various functions. It acts as an emulsifier, solubilizer, detergent, and dispersing agent. First, surfactants provide an emulsion that is stable over the life of the product, allowing the product to be dispensed as a shaving cream composition exhibiting little or no phase separation. Second, surfactants provide lather during the cream application process. Third, surfactants can provide a lather that will remain stable at elevated temperatures, that is, temperatures that the shaving cream composition can reach during heating, typically 35 ° C to 50 ° C. The term "stable" means that the shaving cream will not form a paste in the user's hand or will not run off the user's face, but will maintain substantially the same consistency before, during and after heating. The surfactant mixture is preferably present in both the oxidizing and reducing components, so that both components can be provided as stable emulsions that can be dispensed as a cream.

The water dispersible surfactant includes a nonionic surfactant, more preferably a mixture of two or more nonionic surfactants. Since they are stable in the presence of weak acids and bases, nonionic surfactants can provide formulation flexibility that is generally lacking when using soaps. Preferred nonionic surfactants include polyethoxylated fatty alcohol ethers. These are derived from fatty alcohols with C12-C24, preferably C12-C20, hydrocarbon chains (with a degree of unsaturation of 0-2) ethoxylated with 2-150, preferably 2-100, ethylene oxide units (i.e. ethoxy groups ). Therefore, one or more of the ethoxylated fatty alcohols can have the general formula:

CH₃- (CH₂)_x-CH₂-O- (CH₂-CH₂-OR-)_YH, where x = 10-22 (preferably 10-18), y = 2-150 (preferably 2-100). Examples of such surfactants include Steareth-21, Steareth-100, Myreth-4, Myreth-10, Laureth-4, and Laureth-35. In some embodiments, the water dispersible surfactant may include a mixture of nonionic surfactants having long hydrocarbon chains (C16-C24) and / or nonionic surfactants having medium hydrocarbon chains (C12C14).

ES 2 399 896 T3

The ethoxylated fatty alcohol mixture may include:

(a) at least one ethoxylated fatty alcohol with a long polyethylene oxide chain length (i.e. 21-150, preferably 21-100, ethylene oxide units or ethoxy groups) and at least one ethoxylated fatty alcohol with a short polyethylene oxide chain length (ie, 2-20 ethylene oxide units or ethoxy groups); and / or (b) at least one ethoxylated fatty alcohol with a long polyethylene oxide chain length and a different ethoxylated fatty alcohol with a long polyethylene oxide chain length; and / or (c) at least one ethoxylated fatty alcohol with a short polyethylene oxide chain length and a different ethoxylated fatty alcohol with a short polyethylene oxide chain length.

Preferred long poly (ethylene oxide) chain length ethoxylated fatty alcohols include Steareth100 (100 indicates the poly (ethylene oxide) chain length and Steareth-21. Other poly (ethylene oxide) chain length ethoxylated fatty alcohols may be used Long (ethylene oxide) such as Ceteth-100, Oleth-100, Myreth100, and Beheneth-100. These long poly (ethylene oxide) chain length ethoxylated fatty alcohol surfactants have a preferred HLB range of 15 to 18. The shorter poly (ethylene oxide) chain length ethoxylated fatty alcohols include, for example Example, Steareth-2, Steareth-10, Ceteth-10, Ceteth-20, Steareth-20, Myreth-20, Oleth-20, and Beheneth-20. These shorter polyethylene oxide chain length ethoxylated fatty alcohol surfactants have a preferred HLB range of 4 to 16.

The short and long polyethylene oxide chain length surfactants are included in a ratio that provides the cream with the desired efficacy and aesthetic properties. Levels and types of surfactants can be selected from the HLB match of the ingredients (the non-surfactants) with the HLB of the surfactant system. For this, it is preferred to use a mixture of high and low HLB surfactants. For example Steareth-2 (HLB 4.9) and Stereath-100 (HLB 18.8) can be mixed giving an HLB of about 15. The level of surfactant can be further optimized to provide the desired stability and desired aesthetic formulation properties. Thus, the amounts of the two surfactants can be adjusted to achieve the desired balance of properties. For a shaving cream with good consistency and foaming, a suitable ratio of short polyethylene oxide chain (more hydrophobic) surfactant to long polyethylene oxide chain (more hydrophilic) surfactant would be generally in the range of 2.5: 1 to 1: 2.5, respectively.

In addition to or as an alternative to ethoxylated surfactants, suitable surfactant mixtures may include one or more non-ethoxylated surfactants such as, for example, fatty ether-type or ester-type surfactants (eg, polyglyceryl fatty esters, sugar ethers, sugar esters, esters of sugar derivatives). Examples of fatty esters of the polyglyceryl type include decaglyceryl dipalmitate, decaglyceryl oleate, decaglyceryl stearate, hexaglyceryl monostearate / oleate, decaglyceryl myristate, hexaglyceryl myristate, decagylceryl laurate, triglyceryl stearate, triglyceryl laurate, and hexaglyceryl stearate. Examples of sugar esters include cetearyl polyglucoside, behenyl polyglucoside, myristyl polyglucoside, and cocoyl polyglucoside. Examples of sugar esters include sucrose esters such as sucrose monostearate and distearate. Examples of esters of sugar derivatives include sorbitan esters such as, for example, sorbitan monostearate, sorbitan palmitate, sorbitan oleate, sorbitan sesquioleate, and sorbitan isostearate. Generally, such non-ethoxylated surfactants will be included in the reducing component unless it is also determined that they are stable in the presence of oxidizing agent.

The total amount of water dispersible surfactant in one or both of the shaving cream bases (or in the composition as a whole) is generally in the range of 2% to 15%, preferably 3% to 12%. Including too high a level of surfactants can result in ineffective mixing of the shaving cream bases, which can limit the exothermic reaction between the shaving cream bases, thereby reducing the heat contributed by the shaving cream. shaved off. Including too low a level of the surfactants can result in instability of the shaving cream composition. The mixtures of short and long chain fatty alcohol ethoxylates described hereinbefore can stabilize oil droplets, which are distributed in the aqueous phase and in which the expanding gas (creaming agent) resides.

In certain embodiments, the oxidizing component of a shaving cream composition may include 2% to 8%, preferably 2% to 6% of a nonionic surfactant. In certain embodiments, the oxidizing component may include 1% to 6%, preferably 2% to 4%, of a shorter polyethylene oxide chain length nonionic surfactant such as, for example, Steareth-2 . Alternatively, or additionally, the oxidizing component may include 1% to 6%, preferably 2% to 4%, of a long polyethylene oxide chain length nonionic surfactant such as, for example, Steareth-21. In some embodiments, the oxidizing component may include 1% to 6% of a nonionic surfactant, and 1% to 6% of a different nonionic surfactant.

ES 2 399 896 T3

In certain embodiments, the reducing component of a shaving cream composition may include 2% to 12%, preferably 3% to 8%, of a nonionic surfactant such as, for example, Steareth-100 or Steareth-21. The reducing component can include more than one type of nonionic surfactant. For example, the reducing component may include 1% to 8% of a nonionic surfactant (eg, Steareth-21), and 1% to 8% of a different nonionic surfactant (eg, Steareth -100).

Water is the main component of the composition and is used in amounts sufficient to dissolve or disperse the surfactant components and form the continuous phase of the oil / water emulsion, while providing a stable cream with adequate viscosity and foaming properties. and desired rinse. It is added in a sufficient quantity (qs) until reaching the total of all the components up to 100%. The composition (i.e. each of the components, the oxidant and the reductant, independently of one another) typically includes 55% to 95%, preferably 60% to 90%, more preferably 65% ​​to 85%, of water. In certain embodiments, the oxidizing component of the shaving cream composition may include 60% to 90%, preferably 70% to 85%, water. In some embodiments, the reducing component can include 55% to 90%, preferably 70% to 85%, water. In certain embodiments (eg, embodiments where the reducing component includes a triethanolamine type neutralizer), the reducing component may include 58% to 70% water.

It is preferred that one or both of the shaving cream bases include an emollient to provide desirable cosmetic properties. The oil phase of the emulsion can include any desired emollient that is safe for use in a shaving cream composition, is compatible with the other ingredients of the composition, and provides the desired cosmetic and lubrication properties during shaving. Suitable emollients include mineral oil, petrolatum, squalane / squalene, hydrogenated / unsaturated polyisobutene, and mixtures thereof. These emollients are suitable for use with the surfactant mixtures mentioned above. Preferably, the composition contains 0.25% to 15%, more preferably 0.5% to 12%, and most preferably 0.75% to 8%, of the emollient. The emollient is preferably included in both shaving cream bases. In some embodiments, the oxidizing component of a shaving cream composition may include 1% to 4% of an emollient (eg, mineral oil). In some embodiments, the reducing component of a shaving cream composition may include 1% to 5% of an emollient (eg, mineral oil).

A thickener may be included to improve the consistency and stability of the shaving cream, as well as to adjust its viscosity. The thickener also generally provides body to the shaving cream. The thickener can be a water soluble thickener, a water insoluble thickener, or a mixture thereof. In some embodiments, each component, or both components (preferably both) of a shaving cream composition may include from 0.01% to 15%, preferably from 0.1% to 11%, of a thickener. In certain embodiments, the oxidizing component and / or reducing component of a shaving cream composition may each include 1% to 10%, preferably 3% to 6% of a thickener. The thickener included in the oxidizing component must, of course, be stable in the presence of an oxidizing agent (such thickeners include, for example, polyvinylpyrrolidone).

Shaving cream comprises a fatty alcohol (which is a water-insoluble thickener). Suitable fatty alcohols have a chain length of 12-22 carbon atoms and a degree of unsaturation of 0-1. The fatty alcohol is selected from myristyl alcohol, lauryl alcohol, cocoyl alcohol, cetyl alcohol, cetearyl alcohol, oleyl alcohol, stearyl alcohol, and behenyl alcohol. Generally, the composition may include 0% to 15%, preferably 0.1% to 15%, more preferably 1% to 15%, most preferably 2% to 8%, of an alcohol-type thickener. fatty.

Other examples of suitable water-insoluble thickeners include ethoxylated fatty esters (eg, PEG-150 distearate, PEG-150 pentaerythrityl tetra-stearate), fatty esters (eg, pentaerythrityl tetraisostearate, pentaerythrityl tetrastearate, neopentanoate of isostearyl, and mixtures thereof) and high-melting waxes (eg, hydrogenated castor oil). Such thickeners are especially desirable for maintaining the viscosity of the product at the temperatures reached during the exothermic reaction and preventing it from running off the skin of the user. In some embodiments, the oxidizing component and / or reducing component of a shaving cream composition may include 0.1% to 3% of said thickener, such as, for example, hydrogenated castor oil or PEG-150 distearate.

In addition to the fatty alcohol type thickener, or in some cases in place thereof, the composition may include other thickeners. Examples of suitable thickeners include water soluble thickeners such as hydroxyalkyl cellulose polymers, e.g. eg, hydroxyethylcellulose and hydroxypropylcellulose (marketed under the trademarks “Natrosol” and “Klucel”, respectively), carboxymethylcellulose, cellulose methyl ether (marketed under the trademark “Methocel”), hydroxypropyl starch phosphate (marketed under the trademark “ Structure XL "), other polysaccharides such as xanthan gum, guar gum, modified starch and carrageenan, and mixtures thereof. In some embodiments, the reducing component of a shaving cream composition may advantageously include up to about 1% of a water soluble thickener such as hydroxyethyl cellulose.

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As a thickener and / or to increase lubricity, the shaving cream composition may also include a lubricious water soluble polymer. Such polymers typically have a molecular weight of between 300,000 daltons and 15,000,000 daltons. Suitable polymers include, for example, polyvinylpyrrolidone (PVP), PVP / vinyl acetate copolymer, polyethylene oxide, polyacrylamide, and mixtures thereof. If a lubricious water soluble polymer is included, it is typically provided in the shaving cream composition in an amount of 0.005% to 4%, preferably 0.01% to 1.5%, of the composition. In some embodiments, a reducing component of a shaving cream composition may advantageously include up to 1% of a lubricious water soluble polymer such as polyacrylamide.

As discussed hereinabove, heating reagents generally include an oxidizing agent, included in the oxidizing component, and a reducing agent, included in the reducing component. Suitable oxidizing agents include peroxides such as hydrogen peroxide (typically added as a 35% solution), benzoyl peroxide, peroxomonosulfate, peroxodisulfate, urea hydrogen peroxide, and t-butyl peroxide. In some embodiments, the oxidizing component of a shaving cream composition can include from 2% to 10% of an oxidizing agent. In some embodiments, the oxidizing component may include from 12% to 16% of an oxidizing agent such as hydrogen peroxide (35%) (corresponding to an amount of 4% to 6% of active H2O2).

Suitable reducing agents are those that will react with the oxidizing agent when the two components of the formulation are mixed, producing a perceptible exothermic reaction. Suitable reducing agents should also be safe for use on human skin in the amounts used in the formulation. The reducing agent can include, for example, thiosulfate and sulfite compounds such as, for example, sodium sulfite, sodium thiosulfate (e. g., sodium thiosulfate pentahydrate), ammonium thiosulfate, potassium thiosulfate, and thiourea. Other suitable reducing agents include compounds with a thiourea backbone, such as 1,5-diethyl-2-thiobarbituric acid or its derivatives, or ascorbic acid. Mixtures of the above reducing agents with other suitable reducing agents can also be used. In some embodiments, the reducing component of a shaving cream composition may include 2% to 10%, preferably 3% to 8%, of a reducing agent.

The oxidizing agent and reducing agent are generally included in approximately stoichiometric proportions with respect to the redox reaction that will occur. The predominant redox reaction between hydrogen peroxide and sodium thiosulfate is as follows:

2S2O3^2- + H2O2 - S4O6^2- + 2OH^-

In the presence of a suitable amount of an effective catalyst, the reaction is as follows:

Na2S2O3 + 4H2O2 —— Na2SO4 + 3H2O + H2SO4

The total amount of both agents is selected to provide the desired level of heat and duration of the exothermic reaction. Preferably, the maximum temperature obtained by the shaving cream during the reaction is 30 ° C to 60 ° C, and this temperature is reached 10 seconds to 45 seconds after mixing the components (this is the temperature that the shaving cream reaches when the oxidizing component and the reducing component of the shaving cream are mixed in a beaker in stoichiometric amounts providing a total weight of 10 grams of the shaving cream; When a quantity of 5 grams to 8 grams of shaving cream is applied to the skin, the actual temperature on the skin is typically 28 ° C to 45 ° C). When using the oxidizing agents and reducing agents described above, the shaving cream composition generally includes 2% to 10% of the oxidizing agent and 2% to 10% of the reducing agent, in approximately stoichiometric proportion.

To obtain the heat profile described hereinbefore, it may be advantageous to include a catalyst in the shaving cream composition. The catalyst is selected to catalyze the exothermic reaction but without producing negative effects on the skin or affecting the properties of the shaving cream. The catalyst is generally included in the reducing component of the shaving cream composition. Suitable catalysts for the exothermic reaction described above include sodium molybdate (eg, sodium molybdate dihydrate), potassium molybdate, ammonium molybdate, sodium tungstate, potassium tungstate, and mixtures thereof. The composition generally includes 0.1% to 1.5%, preferably 0.2% to 1.0%, of the catalyst.

If the exothermic reaction generates an acid, as is generally the case with the reaction of oxidizing and reducing agents discussed hereinabove, it is preferred that the composition (eg, reducing component) also includes a neutralizing agent ( a neutralizer). The neutralizing agent is selected and provided in an amount sufficient to neutralize a sufficient amount of the acid so that the exothermic reaction is complete and the shaving cream composition does not irritate the skin of the user. Preferably, virtually all of the acid is neutralized. Suitable neutralizing agents include, for example, triethanolamine,

ES 2 399 896 T3 oxides (eg metal oxides), hydroxides (eg metal hydroxides), and metal carbonates such as alkali metal carbonates (eg sodium, potassium), alkaline earth metals (eg, magnesium, barium), or transition metals (eg, zinc). For example, the neutralizing agent can include calcium oxide, potassium hydroxide, sodium hydroxide, potassium bicarbonate, sodium bicarbonate, or aluminum hydroxycarbonate. In some embodiments, the shaving cream composition (preferably the reducing component of the shaving cream composition) may include from 0.5% to 10% of said neutralizer. For example, the reducing component can include 1% calcium oxide or 7% triethanolamine.

The shaving cream composition may include additional non-ionic surfactants, typically in an amount of 1% to 6%, preferably 2% to 5%. The shaving cream composition may also include additional amphoteric auxiliary surfactants, typically in an amount of 0.1% to 3.0%, preferably 0.2% to 1.5%. These additional surfactants are typically included in the reducing component, unless they are determined to be stable in the presence of oxidizing agent.

Suitable nonionic co-surfactants include the fatty esters of polyhydroalcohols (eg, polyglyceryl oleates), fatty esters of polyoxyethylene oxide of glycerides, and fatty amides, especially the alkyl substituted fatty amides. These surfactants will generally have 6 to 100, preferably 20 to 50, ethylene oxide units per molecule. Typical nonionic co-surfactants include, for example, PEG-40, hydrogenated castor oil, and decaglycerol monooleate. Suitable amphoteric surfactants include, for example, betaines and sultaines such as cocoamidopropyl betaine, cocodimethyl carboxymethyl betaine, cocosultaine, and the like. These amphoteric surfactants may tend to act as cream enhancers and stabilizers, providing greater heat stability to the cream and preventing paste formation. It is preferred that the composition includes 0.2% to 1.5% of an amphoteric surfactant as a cream enhancer. Other suitable auxiliary surfactants that can function as cream enhancers include sodium lauroylactylate, sodium caproylactylate, and short chain alkylpolyglycosides (e.g. (g., alkylpolyglycosides with carbon chain lengths of C12 or less such as, for example, laurylglucoside, caprylglucoside, or caprylylglucoside).

Although not necessary to obtain a useful shaving cream composition, other cosmetic ingredients may be advantageously added to improve the aesthetics of the application and / or achieve other shaving benefits. Of course, said ingredients must be compatible and stable with the reducing component or with the oxidizing component. For example, the composition may include one or more of the following components: beard wetting agents, skin conditioning agents (eg, exfoliants, moisturizers) (eg. e.g. vitamin precursors and derivatives such as vitamins A, C and E, aloe, allantoin, panthenol, alpha-hydroxy acids, beta hydroxy acids, phospholipids, triglycerides, botanical oils, amino acids), cream enhancers (other than surfactants cream enhancing aids described hereinbefore), emollients (eg, sunflower oil, fatty esters, squalane, quaternary compounds (eg, Polyquaternium-10), humectants (eg. g., glycerin, sorbitol, pentylene glycol), phospholipids (used, eg, to encapsulate skin conditioning agents), fragrances, colorants, antioxidants, preservatives, and other similar ingredients. In some embodiments, the reducing component of a shaving cream composition can include 0.1% to 1.5% of a fragrance.

The oxidizing component and the reducing component are kept separate from each other until the product is dispensed. This can be accomplished by using any desired type of two component packaging. The two components are mixed, either automatically when dispensed from the container or manually by the user after dispensing, to form a uniform shaving cream that heats up when oxidizing and reducing agents react with each other and foams when spread over the skin.

As illustrated below, the oxidizing and reducing components can be formed by adding the oxidizing agent and the reducing agent, respectively, to the first and second shaving cream base. Preferably, the first and second shaving cream bases are practically identical. Therefore, advantageously, the oxidizing agent and the reducing agent can each be added to separate parts of the same shaving cream base. Using a single shaving cream base to make both components generally simplifies manufacturing and can facilitate mixing of the two components during or after dispensing.

The shaving creams described above can be formed by any suitable manufacturing process. An example of a suitable process is as follows:

Reducing component An oil phase, containing nonionic emulsifiers, fatty alcohols and thickeners, is mixed at 75 ° C. The oil phase is added to an aqueous phase with rapid stirring and mixed at 75 ° C - 80 ° C for 30 minutes. A neutralizer is added with moderate stirring at 70 ° C. A reducing agent is added at 60 ° C and a catalyst at 55 ° C. After subsequent cooling and under stirring conditions, fragrance and dye are added at 40 ° C. Finally, the mixture is homogenized, using an external homogenizer (type IKA), until it reaches the consistency of a smooth cream.

Oxidizing component: An oil phase, containing nonionic emulsifiers, fatty alcohols and thickeners, is mixed at 75 ° C. The oil phase is added to an aqueous phase with rapid stirring and mixed at 80 ° C for 30 minutes. The mixture is cooled and subjected to moderate agitation using a standard type propellant and a side scraper. The mixture is homogenized at 55 ° C by passing through an external homogenizer to another

ES 2 399 896 T3 mixing vessel. The oxidant is then added at 35 ° C and mixed well. Finally, the mixture is homogenized again until it reaches the consistency of a smooth cream.

The following examples are intended as illustrative, and not limiting.

Example 1

A shaving cream composition is prepared with the following components.

<td></td><td>REDUCING COMPONENT</td><td>OXIDIZING COMPONENT</td>

<td>Ingredients</td><td>% in weigh</td><td>% in weigh</td>

<td>Water</td><td> 74,10</td><td> 79,5</td>

<td>Cetearyl alcohol</td><td> 2,0</td><td> 2,0</td>

<td>Steareth-2</td><td> 3,0</td><td> 3,5</td>

<td>Steareth-21</td><td> 2,0</td><td> 1,5</td>

<td>Sodium molybdate</td><td> 0,7</td><td></td>

<td>Sodium thiosulfate pentahydrate</td><td> 6,5</td><td></td>

<td>Hydrogen peroxide (35%)</td><td></td><td> 11,5</td>

<td>Castor wax</td><td></td><td> 2,0</td>

<td>Vaseline</td><td> 3,0</td><td></td>

<td>Triethanolamine</td><td> 7,0</td><td></td>

<td>Fragrance</td><td> 1,0</td><td></td>

<td>FD&amp;C Blue # 1, 1%</td><td> 0,4</td><td></td>

Example 2

A shaving cream composition is prepared with the following components.

<td></td><td>REDUCING COMPONENT</td><td>OXIDIZING COMPONENT</td>

<td>Ingredients</td><td>% in weigh</td><td>% in weigh</td>

<td>Water</td><td> 71,3</td><td> 78,0</td>

<td>Cetyl alcohol</td><td> 6,0</td><td> 4,0</td>

<td>Steareth-100</td><td> 3,0</td><td></td>

<td>Steareth-21</td><td> 2,0</td><td> 4,0</td>

<td>Sodium molybdate</td><td> 0,7</td><td></td>

<td>Sodium thiosulfate pentahydrate</td><td> 7,0</td><td></td>

<td>Hydrogen peroxide (35%)</td><td></td><td> 14,0</td>

<td>Polyacrylamide</td><td> 0,2</td><td></td>

<td>Polyquaternium-10</td><td> 0,8</td><td></td>

<td>Triethanolamine</td><td> 7,0</td><td></td>

<td>Vaseline</td><td> 1,0</td><td></td>

<td>PEG-150 distearate</td><td> 0,3</td><td></td>

<td>Fragrance / dye</td><td> 0,7</td><td></td>

When dispensed and mixed, the formulations described above create a dense, warm cream on the skin, comparable to the type of cream generally seen when using soap-based shaving creams, but without the negative characteristics of soap-based creams. in soap. The application to the skin of an amount of shaving cream suitable for use in shaving (approximately 8 grams) provides a pleasant sensation of heat. The cream does not melt with heat and lasts the entire time you shave.