MXPA06005253A - Antiperspirant compositions - Google Patents

Abstract

An antiperspirant composition comprising an aqueous phase, an antiperspirant salt and a polymer having Bronsted acid groups, characterised in that the antiperspirant salt sand polymer are suspended in the aqueous phase and the composition has a Sauter mean particle size (D[3,2]) of 30 microns or less.

Description

ANTITRANSPIRANT COMPOSITIONS FIELD OF THE INVENTION This invention relates to the field of cosmetic compositions that give an antiperspirant and deodorant benefit. More specifically, it relates to aqueous antiperspirant compositions comprising a suspension of an antiperspirant salt and a polymer having Bronsted acid groups.

BACKGROUND OF THE INVENTION Antiperspirant cosmetic compositions are well known. The antiperspirant cosmetic compositions comprise an antiperspirant salt, such as an aluminum or aluminum / zirconium astringent salt, in combination with a cosmetically suitable vehicle. Such antiperspirant cosmetic compositions are available in a variety of product forms, for example, as bars, creams, soft solids, roll-on lotions, aerosols, pump sprays and squeezing sprays. Although such compositions provide a degree of anti-transpiration and reduction of bad odor, there are problems associated with their use and there is always the desire for improved performance. A problem encountered by some people is that the application of certain antiperspirant compositions, in particular those having a high level of antiperspirant astringent salt, leads to skin irritation. Other problems include formulation difficulties with the high levels of active ingredients sometimes required and incompatibility between certain components of the composition. An objective of the present invention is to reduce perspiration and achieve excellent protection of body odor without the use of high concentrations of conventional antiperspirant or deodorant agents. The above problems have been solved in a variety of ways in the past, examples including the use of certain polymers as antiperspirant actives. WO 93/241 05 (Tranner) describes the use of particular water insoluble film forming polymers with conventional antiperspirant salts which are optional components, not essential in the compositions of the invention. The examples given including antiperspirant salt also comprise octylacrylamide / acrylate co-polymers or PVP / acrylates. No reference is made to the interactions between the antiperspirant salts and the polymers. References are also made to the film-forming polymers in JP 229081 0 (Nagagawa et al) and WO 95/27473 (Causton and Baines). An alternative approach is described in EP 701 81 82 (Abrutyn et al), wherein the porous polymer beads are claimed to be capable of absorbing the sweat components. Polymers have also been used to enhance the performance of antiperspirant salts by increasing the residual amount of antiperspirant salt in the skin. Thus, EP 222580 (Klein and Sykes) describes the use of dimethyldiallyl ammonium chloride polymers (DMDAAC) for this purpose. The use of DMDAAC / acrylic acid co-polymers to thicken personal care products is described in EP 266, 1111 (Boothe et al) and EP 478, 327 (Melby and Boothe). The last of these patents discusses the thickening of aqueous compositions containing metal by said copolymers. Aqueous compositions comprising a polymer containing acrylic acid and an antiperspirant salt are described in WO 98/50005 and WO 98/48768 (Ron et al). In these patents, the proposed invention relates to the inverse thermal viscosity benefit of the polymer. US 5,122,262 and US 5,271,934 (Goldber et al) disclose antiperspirant compositions containing microcapsules comprising an antiperspirant salt encapsulated within a water soluble shell possessing a bioadhesive. Polyacrylic acid is described as a possible component of both the water-soluble shell and the bioadhesive. WO 02/49590 (Smith et al) discloses antiperspirant compositions comprising an antiperspirant salt and a polymer having Bronsted acid groups which, in the presence of water, acts as a co-gellant for the antiperspirant salt; however, unlike the case in the present invention, the antiperspirant salt and the polymer are kept physically separate prior to application.

BRIEF DESCRIPTION OF THE INVENTION We have discovered that antiperspirant compositions having superior performance and stability can be prepared by suspending an antiperspirant salt and a polymer having Bronsted acid groups in an aqueous phase, provided that the particle size of the composition is kept low enough Thus, according to a first aspect of the present invention, there is provided an antiperspirant composition comprising an aqueous phase, an antiperspirant salt and a polymer having Bronsted acid groups, characterized in that the antiperspirant salt and a polymer are suspended in the aqueous phase and the composition has an average Sauter particle size (D [3,2]) of 30 microns or less. According to a second aspect of the invention, there is provided a cosmetic method for achieving an antiperspirant and / or deodorant benefit, said method comprising applying to the human body a composition as described in the first aspect of the invention. According to a third aspect of the present invention, there is provided a method for the manufacture of an antiperspirant composition, said method comprising suspending in an aqueous phase an antiperspirant salt and a polymer having Bronsted acid groups, the composition to give an average Sauter particle size (D [3.2J) of 30 microns or less. According to a fourth aspect of the present invention, there is provided a product comprising a composition as described in the first aspect of the invention and a suitable applicator for roll-on application of the composition.

DESCRI PCI DETAILED I NVENTION The antiperspirant compositions of the present invention can give excellent results in terms of anti-transpiration and deodorance. They are also surprisingly stable, well dispensed and have acceptable sensory properties. The stability of the compositions of the invention is particularly surprising when one considers the strong interaction that occurs between the antiperspirant salt (AP) and the polymer having Bronsted acid groups in the presence of water. The interaction is chemical in nature and results in the production of co-gel particles. These particles have to be relatively small, if they are to be formulated in a stable antiperspirant composition. Typically, the co-gel particles have an average Sauter particle size (D [3,2]) of 30 microns or less, in particular 25 microns or less, and especially 20 microns or less. Measurements of particle size can be made using standard light scattering techniques, in instruments such as the Malvern Mastersizer. The antiperspirant compositions according to the invention have an average Sauter particle size (D [3,2]) of 30 microns or less, preferably 25 microns, and more preferably 20 microns or less. When processing the composition to have these particle sizes relatively low, one can gain benefits in terms of stability, dispensed and / or sensory. The average Sauter particle size (D [3.2j) of antiperspirant compositions according to the invention is a measurement made in the complete composition, different dispersed phase components of the co-gel particles (such as oil droplets) being included in the determination.

Polymers The polymers used in the present invention have groups of Bronsted acid that can interact with polyvalent hydrated metal salts, such salts resulting from the addition of AP salts to the aqueous environment of the composition. It is preferred that the polymer acts as a co-gellant for the AP salt. It is highly preferred that the polymer be soluble in water. A simple test that can be used to determine whether or not a water-soluble polymer is capable of acting as a co-gellant for a given AP salt is to mix aqueous solutions of the polymer and the AP salt and look for an increase in viscosity. The water solubility of the polymers used in the present invention, when measured at 37 ° C, is preferably 1 μg / L or greater, more preferably 50 g / L or greater, and most preferably 1 00 g / L or greater. It is desirable that polymers form true solutions, instead of dispersions, in water; such true solutions usually have an absorbance of less than 0.2, preferably less than 0.1 (for a path length of 1 cm to 600 nm) measured at 20 ° C using a Pharmacia Biotech Ultrospec 200 spectrophotometer or similar instrument. It is also desirable that the polymer be soluble in water at pH 7; obtaining said pH generally requires a certain amount of neutralization of the Bronsted acid groups present. The Bronsted acid groups in the polymer may be present in their protonated form or may be present in their neutralized form as groups of salts. Both partially neutralized or fully neutralized acid polymers can be employed. Suitable Bronsted acid groups include carboxylic acid groups, sulfonic acid groups and phosphonic acid groups. The carboxylic acid groups are particularly preferred. Bronsted acid groups are preferably present at a concentration of more than 0.1 mmol per gram of polymer, more preferably at a concentration of more than 1.0 mmol per gram of polymer and most preferably at a concentration of more than 3.0 mmol. per gram of polymer. These preferred levels refer to Bronsted monobasic acid groups and should be reduced pro rata for polybasic Bronsted acid groups. Latent Bronsted acid groups, such as anhydrides or other groups that generate Bronsted acid groups in addition to water, may also be present in the polymer used to prepare the compositions of the invention. Preferred polymers are organic polymers, in particular, organic polymers possessing only limited positive charge - for example, organic polymers having less than 50 mol%, preferably less than 25 mol%, of positively charged monomer units. Especially preferred organic polymers are nonionic and ammonium polymer. Normal polymers have carbon skeletons, optionally interrupted by ester or amide bonds. The acid value of a polymer is a widely used means of characterization. Acid values generally express the acidity of a polymer in terms of the number of milligrams of potassium hydroxide base required to completely neutralize one gram of the polymer. In this way, the unit of measurement can be abbreviated to mg KOH / g.

The polymers used in the present invention may have acid values greater than 1 60. Preferred polymers have acid values greater than 320 or even greater than 450. Particularly preferred polymers have acid values greater than 580. These acid values are based on the polymer in its fully protonated state; that is, the actual degree of neutralization use of the polymer is ignored with respect to the "acid value". The acid values can be measured experimentally or can be estimated theoretically. When the latter method is used, the acid anhydride groups present in a polymer should be counted as two acid groups, such anhydrides are generally hydrolyzed to di-acids by potassium hydroxide. Preferred carboxylic acid groups can be introduced into the polymer by inclusion of monomers, such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, crotonic acid, maleic anhydride or itaconyl anhydride in the polymer. When the sole source of Bronsted acid groups are anhydride monomers, it is required that the anhydride groups be at least partially hydrolyzed before incorporation of the polymer into the composition. Polymers comprising a mixture of any of the above acid and / or anhydride monomers can also be advantageously employed. Particularly preferred polymers are those derived, at least in part, from maleic acid and / or maleic anhydride monomers. Sometimes it is desirable to include other monomers in the polymer.

Suitable monomers include methyl vinyl ether, C-β-C8 alkyl acrylates and methacrylates, vinyl acetate, ethylene and propylene. The inclusion of such monomers can aid polymer synthesis, easy handling and / or polymer formulation and can improve polymer performance as a co-gelling agent. The molecular weight of the polymer is preferably in the range of 500 to 5,000,000, in particular 1, 000 to 3, 000, 000 and especially 1, 000 to 2,500, 000. The selection of an appropriate molecular weight of the polymer can lead to to benefits in terms of ease of formulation, product aesthetics (in particular product sensation) and product performance. The polymer is preferably incorporated into the composition in an amount from 0.01% to 10% by weight, more preferably from 0.05% to 5% by weight, and most preferably from 1% to 3% by weight of said composition.

Antiperspirant salts The antiperspirant salts for use herein are usually selected from astringent salts including, in particular, aluminum and aluminum / zirconium salts mixed, including both inorganic salts, salts with organic anions and complexes. Preferred astringent salts are salts of aluminum and alumiumiumium zirconium halides and halohydrates, such as chlorohydrates. Aluminum salts that exclude zirconium are especially preferred, these salts being more clearly enhanced in anti-transpiration by the presence of the polymer having Bronsted acid groups. Aluminum halohydrates are usually defined by the general formula AI2 (OH) xQy.wH20, in which Q represents chlorine, bromine or iodine, x is variable from 2 to 5 and x + y = 6, while wH20 represents a variable amount of hydration. Especially effective aluminum halohydrate salts, known as activated aluminum chlorohydrates, are described in EP006,739 (Unilever PLC and NV). Some activated salts do not retain their enhanced activity in the presence of water, but are useful in substantially anhydrous formulations, ie, formulations that do not contain a different aqueous phase. Zirconium salts are usually defined by the general formula ZrO (OH) 2- xQx.wH20, in which Q represents chlorine, bromine or iodine; x is from about 1 to 2; w is from about 1 to 7; and x and w can have both non-integer values. Zirconyl oxyhalides, zirconium hydroxyhalides and combinations thereof are preferred. Non-limiting examples of zirconium salts and processes for making them are described in the Belgian patent 825, 146, Schmitz, issued August 4, 1975 and US patent 4, 223.01 0 (Rubino). The above aluminum and aluminum / zirconium salts can have coordinated and / or bound water in various amounts and / or be present as polymeric species, mixtures or complexes. Suitable aluminum-zirconium complexes frequently comprise a compound with a carboxylate group, for example, an amino acid. Examples of suitable amino acids include tryptophan, phenylalanine, valine, methionine, alanine and, most preferably, glycine.

It is sometimes desirable to employ complexes of a combination of aluminum halohydrates and zirconium chlorohydrates together with amino acids, such as glycine, which are described in US 3,792,068 (Procter and Gamble Co.). Certain of these Al / Zr complexes are commonly called ZA in the literature. ZAG assets generally contain aluminum, zirconium and chloride with a ratio of Al / Zr in a range from 2 to 10, especially 2 to 6, a ratio of AI / CI from 2. 1 to 0.9 and a variable amount of glycine. Assets of this preferred type are available from Westwood, Summit and Reheis. Other active ingredients that can be used include astringent titanium salts, for example, those described in GB 2,299, 506. Antiperspirant salts are preferably incorporated in a composition in an amount from 0.5-60, in particular from 3 to 30% or 40%. % and especially from 5 or 10% up to 30 or 35% of the weight of the composition. The proportion of AP salt in a composition excludes the weight of any water of hydration present in the salt prior to its addition to the aqueous phase, but includes the weight of any complexing agent present. The weight ratio of the AP salt to the polymer is preferably 50: 1 or less, more preferably is from 25: 1 to 1: 10, and most preferably is from 1: 1 to 1: 5.

The aqueous phase The aqueous phase is usually a continuous phase and may comprise a water-soluble species, in addition to water by itself. However, water is usually the main component of this phase and usually responds by 40% or more, in particular 55% or more and especially 70% or more of the composition. Other water-soluble liquids may also be present; for example, short chain alcohols (C? -C4), in particular monohydric alcohols, such as ethanol or isopropanol, can be present, usually at a level from 1 to 50%, in particular from 2 to 40% and especially from 5 to 30% by weight of the composition. In certain preferred embodiments, the short-chain polyhydric alcohols (d-C) are employed, suitable materials include glycerol and propylene glycol. Alternatively, longer-chain water-soluble polyhydric alcohols, such as dipropylene glycol or polyethylene glycol, may be employed.

Optional additional components An emollient oil, normally accompanied by an emulsifier, is a highly preferred additional component of the compositions according to the invention. Such materials can intensify the sensory benefits delivered. The total level of oil or emollient oils used can be from 0.1% to 20% of the total weight of the composition. Suitable emollient oils include cyclomethicone, dimethicone, dimethiconol, isopropyl myristate, isopropyl palmitate, sunflower oil, C 1 2 -CI 65 alcohol benzoate, PPG-3 myristyl ether, octyl dodecanol, C 7 -C 14 isoparaffins, adipate di-isopropyl, isosorbide laurate, PPG-14 butyl ether, PPG-1 stearyl ether, glycerol, propylene glycol, poly (ethylene glycol), hydrogenated polyisobutene, podecene, phenyl trimethicone, dioctyl adipate and hexamethyl disiloxane. The emollient oil is usually part of an oil-in-water emulsion composition having a continuous aqueous phase with emulsified oil droplets and AP-polymer salt co-gel particles suspended therein. In such compositions, the total level of oil or emollient oils used is preferably from 0.2% to 5% of the total weight of the composition. As indicated above, emulsifiers can be used in the compositions according to the invention. The total level of emulsifier or emulsifiers used can be from 0.1% to 10% of the total weight of the composition. Suitable emulsifiers include steareth-2, steareth-20, steareth-21, ceteareth-20, glyceryl stearate, cetyl alcohol, cetearyl alcohol, PEG-20 stearate and dimethicone copolyol. Desirable emulsifiers in certain compositions of the invention are perfume solubilizers and washing agents. Examples of the above include hydrogenated castor oil-PEG, available from BASF in the Cremophor RH and CO ranges, preferably present up to 1.5% by weight, more preferably 0.3 to 0.7% by weight. Examples of the latter include poly (oxyethylene) ethers. A fragrance oil or perfume is a highly preferred additional component of the compositions according to the invention. Suitable materials include conventional perfumes and so-called deo-perfumes, as described in EP 545, 556 and other publications. The levels of incorporation are preferably up to 4% by weight, in particular from 0.1% to 2% by weight, and especially from 0.7% to 1.7% by weight of the composition. A suspending agent can also be used to further enhance the stability of compositions according to the invention. The total amount of suspending agent or agents can be from 0.1 to 5% by weight of the total weight of the composition. Suitable suspending agents include quaternium-8 bentonite, quaternium-1 hectorite 8, silica (in particular, finely divided or smoked silica) and propylene carbonate. An additional component that can sometimes increase deodorant performance is an organic anti-microbial agent. The levels of incorporation are preferably from 0.01% to 3%, more preferably from 0.03%) to 0.5% by weight of the composition. Preferred organic anti-microbial agents are those that are more effective than ethanol. Anti-microbials that are sunbathing in water are also preferred. Preferred organic antimicrobials are also bactericidal, for example, quaternary ammonium compounds, such as cetyltrimethylammonium salts; chlorhexidine and salts thereof; and diglycerol monocaprate, diglycerol monolurate, glycerol monolaurate and similar materials, as described in "Deodorant Ingredient" (I ngredientes deodorants), S.A. Makin and M. R. Lowry, in "Antiperspirants and Deodorants", Ed. K. Laden (1 999, Marcel Dekker, New York). More preferred anti-microbials are polyhexamethylene biguanide salts (also known as polyaminopropyl biguanide salts), with one Cosmocil CQ example available from Zeneca PLC; 2 ', 4,4'-trichloro, 2-hydroxy-diphenyl ether (triclosan); and 3, 7, 1-trimethyldodeca-2,6, 1-trienol (farnesol). The most preferred anti-microbials are transition metal chelators, in particular those which have a binding coefficient for iron (I I I) of more than 1026, such as diethylenetriaminepentaacetic acid (DTPA) and salts thereof. One or more of the following additional components may also be included in the compositions of the invention: colorants; preservatives, such as C! -C3 alkyl parabens; and irritation reducing agents, such as borage seed oil or ricinoleic acid.

Product forms The composition of the invention is usually an emulsion, in particular an oil-in-water emulsion. The composition is preferably used as a roll-on product, together with a suitable applicator for roll-on application of the composition and usually comprises a spinning ball. Such roll-on compositions usually have a continuous aqueous phase and frequently an emulsified oil phase, in addition to co-gel particles suspended from the AP-polymer salt. However, other product forms are possible, the composition of the invention is possibly a mild atomizer, stick or solid product, with the addition of suitable auxiliaries. The aerosol spray compositions can be prepared by adding a polar propellant, such as dimethyl ether to an aqueous ethanol base. The stick and soft compositions can be prepared as water-in-oil emulsions, the AP-polymer salt co-gel particles being suspended in the water droplets. This last product structure can also be used for roll-on and atomizer products.

MANUFACTURING METHODS The method for the manufacture of antiperspirant compositions according to the invention comprises the suspension in an aqueous phase of an antiperspirant salt and a polymer having Bronsted acid groups, the composition being shared to give an average particle size. of Sauter (D [3,2]) of 30 microns or less. The cut used normally produces AP-polymer salt co-gel particles suspended in the aqueous phase. The method can also involve the emulsification of oil in the aqueous phase, producing an oil-in-water emulsion. In a preferred manufacturing method, the method comprises adding a suspension of AP-polymer salt co-gel particles in water to an oil-in-water emulsion, the composition being cut to give an average Sauter particle size. (D [3,2j) of 30 microns or less.

EXAMPLES In the following examples, the comparative examples are indicated by letters and examples according to the invention are indicated by numbers. All percentages are by weight. The percentages indicated in the Tables are percentages by weight of the total composition. Example 1, as detailed in Table 1, was prepared as follows. A 20% aqueous solution of the Gantrez S-95 co-polymer was slowly added to a 50% aqueous solution of ACH, while stirring at 8000 rpm using a Silverson L4RT laboratory scale mixer. The addition was carried out at room temperature and resulted in an increase in temperature. Stirring was continued for 10 minutes after the addition was complete and the resulting viscous liquid / gel mixture was allowed to cool again to room temperature. Volpo S-2, Brij 721, and sunflower oil at 85 ° C were heated. In a separate vessel, the water was heated to the same temperature. While stirring at 4500 rpm, the water was added to the oil / surfactant mixture, maintaining the temperature at 85 ° C. Stirring at 4500 rpm was continued at 85 ° C for 10 minutes and then while cooling the mixture at 35 ° C. The viscous liquid / gel mixture prepared from ACH and the co-poimer of Gantrez S-95 was then added while stirring at 4500 rpm. Following cooling to 25 ° C, the perfume was added and the mixture was stirred for an additional two minutes. Comparative Example A was prepared in a manner analogous to Example 1, but without the addition of Gantrez S-95 to the ACH solution.

Table 1 1 . Ex. Reheis Added as a 50% aqueous solution to give 17.5% ACH solids in the final products. 2. Ex. I nternational Specialty Products, I nc. Added as a 20% aqueous solution to give 2.0% co-polymer solids in the final product. 3. Eg Croda. 4. Ex. Uniqema Using standard "hot room" evaluation protocols, the underarm anti-transpiration performance of Examples 1 and A were compared, using panels of at least 30 female volunteers. In a first test, the average sweat weight reduction resulting from the use of Example 1 was 17% greater than that resulting from the use of Example A. In a second test, the average sweat weight reduction resulting from the use of Example 1 it was 18% greater than that resulting from the use of Example A. Both of these results were significant at the 95% level. The average Sauter particle size (D [3,2]) of a liquid / gel mixture prepared from a 50% ACH solution and a Gantrez S-95 co-polymer solution, prepared as described before, it was measured as 1 7.2 microns using a Malvern Mastersizer. It was found that this composition has a storage stability much higher than the other two compositions of the same components at the same levels having Sauter average particle sizes (D [3.2j) of 45.3 mers and 60.5 mers; these latter compositions are prepared by using smaller amounts of cut. The larger particle size blends were not suitable for use in commercial antiperspirant compositions due to their instability. The compositions detailed in Table 2 can also be prepared according to the invention, using methods analogous to that used in the preparation of Example 1.

Table 2 1 . As in Table 1. 2. Ej International Speciality Products Inc. The amounts indicated are polymer solids. 3. Ej Finetex, Inc. 4. Ej Amerchol Corp.

Claims (11)

1. REIVI NDI CATIONS 1 . An antiperspirant composition comprising an aqueous phase, an antiperspirant salt and a polymer having Bronsted acid groups, characterized in that the antiperspirant and polymer salt are suspended in the aqueous phase and the composition has an average particle size of Sauter (D [3,2]) of 30 microns or less.
2. 2. An antiperspirant composition according to claim 1, wherein the polymer acts as co-gelling agent for the anti-perspirant salt.
3. 3. An antiperspirant composition according to claim 2, wherein the antiperspirant salt and the polymer exist as co-gel particles suspended in the aqueous phase.
4. An antiperspirant composition according to claim 3, wherein the antiperspirant salt and the polymer exist as cogel particles having an average Sauter particle size (D [3,2]) of 30 microns or less.
5. 5. An antiperspirant composition according to any of the preceding claims, wherein the polymer is water soluble.
6. 6. An antiperspirant composition according to any preceding claim, wherein the aqueous phase is a continuous phase.
7. 7. An antiperspirant composition according to claim 67, having emulsified oil droplets and AP-polymer salt co-gel particles suspended therein.
8. 8. An antiperspirant composition according to any one of the preceding claims, wherein the antiperspirant salt is present at a level of from 5% to 35% by weight of the composition.
9. 9. An antiperspirant composition according to any preceding claim, wherein the polymer is present at a level from 0.05% to 5% by weight of the composition.
10. 1 0. An antiperspirant composition according to any of the preceding claims, wherein the weight ratio of the AP salt to the polymer is 50: 1 or less. eleven . An antiperspirant composition according to any of the preceding claims, comprising a perfume at a level from 0.7% to 1.7% by weight of the composition. 2. A product comprising a composition as described in any of the preceding claims and a suitable applicator for roll-on application of the composition. 13. A cosmetic method for achieving an antiperspirant and / or deodorant benefit, said method comprising applying to the human body a composition as described in any of claims 1 to
11. 11. A method for the manufacture of an antiperspirant composition, said method comprising suspending in an aqueous phase an antiperspirant salt and a polymer having Bronsted acid groups, the composition being cut to give an average particle size of Sauter (D [3.2j) of 30 microns or less. (54) Title: COMPOSITIONS ANTITRANSPI RANTES (57) Summary: An antiperspirant composition comprising an aqueous phase, an antiperspirant salt and a polymer having Bronsted acid groups, characterized in that the antiperspirant salt and the polymer are suspended in the aqueous phase and the composition has an average particle size of Sauter (D [3,2J) of 30 microns or less.