GB2031277A - Bicarbonate-containing stick deodorant - Google Patents

Abstract

A stick deodorant comprises from 0.1 to 70% of an alkali metal bicarbonate dispersed or dissolved in a soap based gel which comprises a polyhydric alcohol or a mixture of a polyhydric alcohol and a monohydric alcohol solidified or gelled by a minor amount of an alkali metal salt of a saturated C14 to C20 fatty acid gelling agent.

Description

SPECIFICATION Bicarbonate-containing stick deodorant This invention relates to a stable, saturated fatty acid soap based stick deodorant containing alkali metal bicarbonate as the essential deodorizing agent, and to the method of making said bicarbonatecontaining deodorant sticks.

Cosmetic sticks having antiperspirant and/or deodorizing effects and based on alcoholic soap gels and/or propylene glycol soap gels are known in the prior art and are described in U.S. Patents No.

2,900,306; 2,857,315; 2,933,433; 3,259,545; 2,970,083, Canadian Patent No. 567,499 and British Patent No. 795,773. The deodorizing agents incorporated into such soap gels include halogenated dihydroxydiphenyl methanes, particularly hexachlorophenes, as disclosed in U.S. Patents Nos.

2,900,306 and 2,970,083.

In addition to or in lieu of these deodorizing agents, antiperspirant agents such as sodium zirconium lactate, aluminum hydroxide gel, aluminum chlorhydroxy complex, aluminum hydroxy chloride, sodium aluminum chlorhydroxy lactate complex or mixtures thereof have been added to said propylene glycol soap gel sticks as disclosed in U.S. Patents Nos. 2,857,315; 3,933,433; 3,259,545; and 2,970,083.

Antiperspirants combat axillary odours by inhibiting perspiration through the action of astringent salts such as aluminum and zinc salts and may be irritating to users. On the other hand, deodorants neutralize the objectionable odours resulting from the degradation of the components of sweat due to chemical and microbial attack into foul smelling fatty acids. Deodorants however, do not inhibit sweating, but rather neutralize the odourous degradation products of sweat. This may be by their own odourous properties, by the inhibition of the chemical or microbial decomposition of the fats in the sweat residues, or by reaction with the foul smelling fatty acids. Combinations of these mechanisms may also be involved. Accordingly, deodorants are often not as irritating as antiperspirants.

Sodium bicarbonate has long been recognized for its deodorant properties, and has commonly been used as a deodorant in refrigerators. In addition, plain powdered sodium bicarbonate or diluted with talc, cornstarch, rice-flour, or other suitable filler has been used as an underarm deodorant -- see the Journal of Investigative Dermatology Vol.71946 pages 131-133 and U.S. Patents Nos. 279,195 and 1,558,405.

However, the development of a practical and effective deodorant composition in stick form, which is acceptabie to consumers presents many considerations which are unique. For example, because sodium and potassium bicarbonate have only limited solubility in water, alcohol and other solvents, the preparation of a composition suitable for dispensing in stick form has been an exceedingly difficult and perplexing problem. Furthermore, the limited solubility of the bicarbonates, their compatibility with the other ingredients of conventional stick compositions, the dimensional stability of a stick containing bicarbonates, and the aesthetic appearance and feel on the skin of such a stick are just a few of the additional problems encountered in the preparation of an acceptable carbonate e.g. sodium bicarbonate-containing deodorant stick.

Accordingly, it is a primary object of this invention to provide a non-shrinking, non-stinging, stearate soap based deodorant stick containing an effective amount of an alkali metal bicarbonate as the aetive deodorant, the bicarbonate eliminating the need for bacteriostats as the deodorizing agent.

According to the present invention a deodorant stick comprises from 0.1 to 70% by weight of an alkali metal bicarbonate, (and optionally up to 1 0% suspending agent), dispersed in a soap based gel which comprises a polyhydric alcohol or a mixture of a polyhydric and monohydric alcohol, gelled by a minor amount of an alkali metal salt of a fatty acid containing 14 to 20 carbon atoms. The polyhydric alcohol may be aqueous or anhydrous and may constitute a major amount of the gel.

The alkali metal bicarbonate incorporated into the fatty acid soap based stick will generally be sodium bicarbonate or potassium bicarbonate. It has been found that low levels of bicarbonate, such as 0.1 to 3% can be readily dissolved in an aqueous solution in the preparation of a transparent stick according to the invention. Higher levels, such as about 8% potassium bicarbonate can also be used in the preparation of the solid deodorant sticks. Moreover, larger amounts still of sodium or potassium bicarbonate, beyond their solubility ranges can also be incorporated into such sticks by using an optional suspending agent, with particular effect if micro-pulverized sodium or potassium bicarbonate powder, having a particle size of about 5 to 100 microns and preferably 10 to 25 microns is used. The smaller the bicarbonate particles, the easier is the suspension in the soap based gel.

Extra strength deodorant sticks, i.e. sticks containing more than about 3% bicarbonate, can also be formulated using a suspending agent. Suitable suspending agents are the known bulking agent compounds such as colloidal silica such as "Cab-O-Sil" (trade mark); a pyrogenic silica having a particle diameter between about 0.001 and 0.03 microns as disclosed in British Patent No. 987,301; colloidal (fumed) alumina; finely divided hydrophobically treated clays such as a reaction product of a clay such as bentonite or hectorite with, for example, dimethyldistearyl ammonium chloride; colloidal magnesium alumina silicates; other montmorillonite clays; and also hydrophobically treated montmorillonite clays.

The preferred suspending agents are the hydrophobically treated montmorillonite or hectorite clays available under the trademark "Bentone" which are prepared by reacting a clay such as bentonite or hectorite in a cation exchanging system with a variety of amines. Different amines are reacted to obtain different Bentone suspending agents which may also differ in proportions of SiO2, MgO and Awl203. Such treated clays having a particle size below about 5 microns are commercially available from the NL Industries, Inc. of U.S.A. The suspending agent may be employed in amounts of about 0.1 to 10% and preferably 0.5 to 2% by weight of the total composition.

The transparency of the bicarbonate stick is reduced i.e. the stick becomes opaque as the solubility of the bicarbonate in the soap gel is reduced, because of the increased proportion of suspended bicarbonate. Such opaque sticks which may contain up to 70%, preferably up to 50%, bicarbonate may be very effective stick deodorants and feel like a cream when applied to the skin, without the hardness characteristics of the stick being unduly affected. Partial substitution of talc for bicarbonate may further improve the after-feel of such sticks.

It has further been found that the substitution of water-absorptive insoluble filler materials in finely divided particulate form such as talc, cornstarch and the like for a portion of the bicarbonate content, not to exceed the amount of bicarbonate, can also be incorporated into the soap based gel stick to give a smooth feel and/or water absorbing properties to the product. Such materials act by absorbing sweat e.g. from under the armpit assuring a dry feeling without altering the normal perspiration process.

It has also been found that sodium or potassium bicarbonate buffers and lowers the pH of the soap based stick deodorant from about 10 to about 8.5 to 9, and from 10.5 to 9.5 respectively, thereby reducing possible skin sensitivity without adversely affecting the required hardness characteristics of the stick.

The sodium or potassium soap based gel into which the aqueous bicarbonate solution or suspension is incorporated comprises a polyhydric alcohol or a mixture or a polyhydric and monohydric alcohol, solidified or gelled by means of an alkali metal salt of a saturated fatty acid containing about 14 to 20 carbon atoms. Suitable polyhydric alcohols include glycerin and the lower alkylene glycols of low molecular weight which are liquid at room temperature, such as ethylene glycol, diethylene glycol, butylene glycol. Propylene glycol is preferred. The alcohol content, which includes the polyhydric alcohol and monohydric alcohol (if any), constitutes the major liquid ingredient of instant composition, and may comprise from about 20% to 90% by weight of the total composition.

The monohydric alcohol may be a lower alkanol such as ethanol or isopropyl alcohol and may be substituted for only part of the polyhydric alcohol, in an amount not in excess of 2.5 times the weight of the polyhydric alcohol and preferably not in excess of the polyhydric alcohol content. These combined alcohol containing sticks are also effective as deodorant sticks. However, transparency of the alcohol containing stick is reduced considerably, i.e., said sticks are opaque, not transparent or translucent. The use of ethanol as the sole alcohol base has been found to be undesirable due to its drying out properties, i.e., synaeresis.

The polyhydric alcohol or the combination of a monohydric alcohol such as ethanol with the polyhydric alcohol, specifically propylene glycol is converted into a gel with a solidifying ingredient in a known manner to form the solid cosmetic product. In particular, it is preferred to employ a stearic acid soap as the gelling agent which is formed preferably in situ by the admixture of aqueous alkali such as sodium or potassium hydroxide with a warm solution of stearic acid in propylene glycol or mixture thereof with ethanol. The resulting mixture solidifies to a gel upon cooling. Any type of high molecular weight saturated fatty acid may be used though it is preferred to employ the commercial stearic acid which comprises essentially a mixture of stearic and palmitic acids.The gelling or solidifying agent is used in minor amounts such as from 2 to 1 5% and preferably about 4 to 8% by weight. Although a sodium, potassium, or sodium-potassium stearate is contemplated as the gelling agent, the sodium stearate is preferred.

In addition to the essential components of the present composition, one may also include therein minor amounts of additional components such as perfumes, colouring agents, ultraviolet absorbers to enhance the colour, to improve the aesthetic value and consumer acceptability of the product.

Other optional ingredients which may be incorporated in the stick compositions in minor amounts without adversely affecting the beneficial properties are the potassium, aluminum and amine soaps and emollients and emulsifiers such as silicones, fatty esters, fatty amides, fatty alcohols, and ethoxylated fatty alcohols and acids. The emulsifiers help make the sticks into a melting stick so that upon contact with the skin, a layer of the composition is deposited thereon. Preferred emulsifiers include alkoxylated cetyl alcohol such as polypropylene glycol of the condensate of cetyi alcohol with 20 moles of ethylene oxide, oleyl alcohol, ethoxylated lanolin, particularly "Solulon" (trade mark) which is a polyethylene glycol ether of lanolin alcohols (average 1 6 moles ethylene oxide).

Other optional ingredients which may have beneficial effects on the deodorant stick of the invention are thickeners or viscosity builders which alone or in combination with suspending agents retard the settling out of materials before the gel solidifies. Particularly useful thickeners include cellulosic derivatives such as hydroxyethyl cellose, hydroxypropyl cellulose, sodium carboxymethyl cellulose (CMC) and "Methocel" (trade mark) which is a hydroxypropylmethyl cellulose containing about 23 to 32% hydroxypropyl groups, about 1 6.5 to 20% methyl groups and about 5% NaCI, having a viscosity of about 4000 to 6000 centipoises.

Known bacteriostats may also be added if required to modify the deodorant properties of the stick. The method of making the aqueous bicarbonate-containing deodorant stick of invention generally comprises mixing an aqueous dispersion or solution of the bicarbonate plus suspending agent (when used) with a hot or heated solution of polyhydric alcohol, stearic acid and alkali metal hydroxide, preferably at about 1 600 F; followed by the addition of perfume, colorants and other optional ingredients (if any) to form a homogeneous liquid product; pouring the warm liquid into moulds and cooling the moulds to room temperature.During the cooling period, gelation takes place and the resultant product assumes a rigid form which is capable of application to the skin by yentle rubbing, having a thin film of the composition on the desired areas of the skin. The resultant rigid stick is transparent or opaque, depending on the amount of bicarbonate added and the particular ingredients employed. This stick is stable, i.e., there is no significant separation out of specific ingredients; and it possesses a good shelflife, i.e., no significant synaeresis or shrinkage occurs.

Another method of making the aqueous bicarbonate-containing sticks of the invention comprises the addition of the powdered bicarbonate and filler such as talc (if desired) directly to the hot liquid soap base with agitation, and pouring the warm flowable mixture into containers to harden into deodorant sticks.

A preferred method of making said bicarbonate-containing stick is to combine the stearic acid with sodium carbonate or potassium carbonate to form the sodium or potassium soap and the sodium or potassium bicarbonate in situ. This reaction is shown by the following equation wherein R represents the stearyl radical:

The preferred method of preparing the anhydrous soap based sticks comprises dissolving the alkali metal soap such as the stearate in hot polyhydric alcohol containing a suspending agent; adding the bicarbonate thereto with agitation; followed by the addition of the water absorptive materials, perfume, colouring agents, etc.; and pouring the resulting mixture into containers to cool and solidify.

The following specific Examples illustrate the invention. All amounts and percentages of various ingredients are by weight unless otherwise specified.

EXAMPLES 1-5 (Sodium Soap - Propylene Glycol -Water Based) Example 1 2 3 4 5 Part 1 Propylene Glycol 53.45 53.35 52.45 50.45 45.45 Stearic Acid 6.00 6.00 6.00 6.00 6.00 19.1% Na2O Caustic Soda 3.60 3.60 3.60 3.60 3.60 Part2 Deionized water 35.6 35.6 35.6 35.6 28.20 Sodium Bicarbonate - 0.1 1.0 3.0 Sodium Bicarbonate (micro pulverized) - - - - 15.00 Bentone LT - - - - 0.50 Part 3 Perfume 1.00 1.00 1.00 1.00 1.00 Triclosan (Bacteriostate)1 0.10 0.10- 0.10 0.10 Uvinul 400 (Ultra-violet absorber)2 0.05 0.05 0.05 0.05 0.05 Part4 FDC Blue 1 0.1% of Soln. 0.20 0.20 0.20 0.20 0.20 100.00 100.00 100.00 100.00 100.00 Visual Appearance Trans- Trans- Trans- Trans- Opaque lucent parent parent lucent to Opaque pH(10%AqueousSoln.) 10.32 9.7 9.1 8.9 8.5 1.4,2',4' trichloro-2-hydroxy diphenyl ether 2. 2,4 dihydroxy benzophenone The stearic acid and the propylene glycol are mixed and heated to 1 600 F, followed by addition of the caustic soda.

The Bentone is gradually added to the water with rapid and/or high shear mixing, followed by the addition of the sodium bicarbonate.

The two solutions are mixed together and cooled to 125-130"F. The perfume, bacteriostat and univol are admixed and added to the above mixture, followed by the addition of the colouring agent.

The total mixture is poured into moulds and chilled to solidify into stable deodorant sticks.

These Examples clearly show the buffering affect of the sodium bicarbonate, as well as the improved transparency of the stick at concentrations of 0.1 to 3% bicarbonate content.

The pH measurements are made by dissolving 10 gms of stick deodorant in 90 gms deionized water by heating, and then cooling to room temperature before taking readings.

EXAMPLES 6 AND 7 (Sodium Soap - Propylene Glycol - Ethanol - Water Based) Example 6 7 Part 1 Propylene Glycol 32.80 32.80 Ethanol (95%) 35.75 32.75 Stearic Acid (B Grade) 6.00 6.00 19.1% nazi Caustic Soda 3.60 3.60 Part 2 Deionized Water 20.00 20.00 Sodium Bicarbonate - 3.00 Part 3 Perfume 1.00 1.00 Triclosan (Bacteriostat) 0.10 0.10 Uvinul 400 0.05 0.05 Butyl Stearate 0.50 0.50 Part4 FDC Blue 1 0.1% aq. soln. 0.20 0.20 100.00 100.00 Visual Appearance Opaque Opaque pH 9.5 8.8 The same procedure as in Example 1 to 5 is followed.

These Examples also show the buffering action of the bicarbonate in the presence of a mixture of ethanol and propylene glycol.

EXAMPLES 8 AND 9 (Combining Stearic Acid with Sodium Carbonate) Example 8 9 Part 1 Propylene Glycol 53.45 52.60 Stearic Acid (B Grade) 6.00 6=00 Trichlorocarbanilide (TCC) 0.15 Part2 Deionized water 36.60 33.75 Sodium Carbonate 2.40 2.40 Sodium Bicarbonate 3.00 Bentone LT 0.50 Methocel (thickener) 0.40 Part 3 Perfume 1.00 1.00 Uvinul 400 1.05 0.05 Triclosan (Bacteriostat) 0.05 Part4 FDC Blue 1 0.1% aq. soln. 0.30 0.30 100.00 100.00 Visual Appearance Transparent Opaque pH (10% aqueous Soln.) 9.0 8.8 1. hydroxy propylmethyl cellulose Part 1 is prepared by heating and dissolving the TCC and the stearic acid in propylene glycol at 1600F.

Part 2 is prepared by dissolving the sodium carbonate and/or the sodium bicarbonate in water with mixing and heating to 1 600 F. Methocel is gradually added with rapid mixing followed by the general addition of Bentone.

Part 1 is gradually added to Part 2 and cooled to about 1300 F.

Part 3 ingredients are admixed and added to the above liquid mixture, followed by the addition of the colour. This homogeneous mixture is poured into moulds and chilled.

These Examples are specific to the preferred method of forming the sodium bicarbonate in situ by the addition of stearic acid to the sodium carbonate. The stick containing less than 3% bicarbonate is transparent, whereas the greater quantity of bicarbonate produces an opaque stick.

In Example 9, the total quantity of sodium bicarbonate formed exceeds its solubility in the system so that the excess amount precipitates out as fine particles on the Bentone suspending agent.

EXAMPLES 10-12 Example 10 11 12 Propylene glycol 53.45 53.45 53.45 Stearic Acid 6.00 6.00 6.00 TCC 0.15 0.15 0.15 Deionized water 33.5 33.4 33.4 Caustic Soda (19.1 %) 3.6 3.6 3.6 NaCI - 0.1 Sodium Bicarbonate - - 0.1 Diisopropyl adipate 1.0 1.0 1.0 Benzyl alcohol 1.0 1.0 1.0 Lavender 1.0 1.0 1.0 FDC Blue 1(0.1%) 0.2- 0.3 0.3 U.V.400 0.05 0.05 0.05 DP 300 0.05 0.05 0.05 Example 12 is significantly more transparent than Examples 10 and 11 and retains its transparency after 20 minutes at 0 in a freezer, whereas the other sticks become slightly hazy after freezing, thereby demonstrating the superior stability of the bicarbonate-containing stick.In addition, Example 12 retains its transparency after standing overnight, whereas the other sticks become less transparent.

EXAMPLES 13 AND 14 Cream Sticks Example 13 14 Base A C Part 1 Propylene Glycol 55.0 75.73 Stearic Acid (Double pressed grade) 6.0 Stearic Acid (Triple pressed grade) 5.00 Bentone LT 2.0 1.00 Tallow Fatty Acid 1.00 Part 2 Water 26.48 10.0 Soda Ash (Sodium Carbonate) 2.40 2.37 Part3 Perfume 1.0 1.0 Glycerol Monostearate - 0.5 Procetyl AWS (emulsifier)1 7.0 3.0 D and C Green 8 (1.75%) 0.08 FDC Green 3 (0.1%) 0.04 D and C Red 9 (0.1%) 0.4 100.00 100.00 50% Cream Stick 50% Cream Stick Base A Base C 50% Baking Soda 25% Baking Soda (Micropulver- (Micropulver ized) ized) 25% Italian Talc 100% 100% 1. polypropylene glycol (5 moles) of condensate of cetyl alcohol with 20 moles of ethylene oxide.

Part 1 ingredients are admixed and heated to 1 600F and added to the aqueous solution of Part 2 at 1 F. The mixture is cooled to 1400F and a mixture of Part 3 ingredients are added thereto with mixing to form the cream stick base.

The micropulverized baking soda perse or jointly with the talc powder are mixed with the hot liquid cream base at a temperature of at least 1250 F. The warm flowable mixture is poured into containers and cooled to form a solid stick. These high solid stick deodorants go on the skin like a cream.The talc baking soda sticks give a particularly smooth feel when rubbed on the skin. EXAMPLES 15 AND 16 (Use of Potassium Bicarbonate) Example 15 16 Part 1 Propylene Glycol 52.3 44.3 Sodium Stearate 8.0 8.0 Procetyl AWS 3.0 3.0 Part 2 Deionized water 35.0 35.0 Potassium Bicarbonate - 8.0 Part3 Sodium Chloride 0.2 0.2 Perfume 1.5 1.5 100.0 100.0 Appearance Translucent to Translucent to Transparent Transparent pH (10% aqueous solution) 10.5 9.5 Sodium stearate and procetyl AWS are dissolved in hot propylene glycol at about 1 800 F.

Potassium bicarbonate is dissolved in warm deionized water. Part 2 is added to Part 1 with mixing and Part 3 ingredients are admixed.

Results show the buffering affect of potassium bicarbonate and its usefulness at 8% in solution.

EXAMPLE 17 Example 17 (An hydrous Stick) Propylene Glycol 75.8 Sodium Stearate 8 Procetyl AWS 4 Sodium Bicarbonate (micropulverized) 10 Bentone LT 0.5 Perfume 1.5 FDC Green 3 (0.1% in ethanol) 0.2 100.0 Appearance Greenish opaque Bentone LT is dispersed in propylene glycol and procetyl AWS solution with rapid mixing. Sodium stearate is dissolved in the mixture at about 185 F. The temperature is reduced to 1 600F and the sodium bicarbonate powder is admixed followed by perfume and colour. The product is poured into containers and cooled to form a solid stick.

EXAMPLE 1 8 Example 18 (Substitution of Glycerine for Propylene Glycol) Part 1 Glycerine 50.00 Stearic Acid (Double Pressed Grade) 6.00 Part 2 Deionized water 35.83 Soda Ash (Sodium carbonate) 2.40 Part 3 Perfume 1.50 Triclosan (Bacteriostat) 0.15 Procetyl AWS 4.00 D and C Green 8 (2.75%) 0.08 FDC Green 3 (0.1%) 0.04 100.00 Appearance Transparent Part 1 is prepared by dissolving stearic acid in glycerine at 1 600 F.

Part 2 is prepared by dissolving soda ash in deionized water at 1600 F.

Part 1 is added gradually to Part 2 with mixing and cooled to 1450 F.

Part 3 ingredients are admixed and the solution is poured into containers and cooled to form a solid stick.

Other polyhydric alcohols can be substituted for propylene glycol in part or in total in the above Examples, such as ethylene glycol, butylene glycol, etc. Similarly the ethanol can be replaced by other monohydric alcohols such as isopropyl alcohol. Likewise, other fatty acid soaps can be substituted for the stearate soap.

Ail of the sticks containing the bicarbonate have been found to be a highly effective deodorant without the use of bacteriostat, stable, non-stinging and non-shrinking.

Claims (21)

1. A deodorant stick comprising from 0.1 to 70% of an alkali metal bicarbonate dispersed or dissolved in a soap based gel which comprises a polyhydric alcohol or a mixture of a polyhydric alcohol and a monohydric alcohol solidified or gelled by a minor amount of an alkali metal salt of a saturated C14 to C20 fatty acid gelling agent.

2. A deodorant stick as claimed in Claim 1 containing 3 to 50% of the alkali metal bicarbonate.

3. A deodorant stick as claimed in Claim 1 or Claim 2, wherein the soap based gel contains the monohydric alcohol in an amount not exceeding 2.5 times that of the polyhydric alcohol.

4. A deodorant stick as claimed in any of Claims 1 to 3, wherein the polyhydric alcohol is glycerin or a lower alkylene glycol which is of low molecular weight and which is liquid at room temperature, and wherein the monohydric alcohol is a lower alkanol, the total alcohol constituting from 20 to 90% of the stick.

5. A deodorant stick as claimed in any of the preceding claims wherein the polyhydric alcohol is propylene glycol and the monohydric alcohol is ethanol.

6. A deodorant stick as claimed in any of the preceding Claims wherein the gelling agent constitutes about 2 to 1 5% by weight of the stick.

7. A deodorant stick as claimed in any of the preceding Claims wherein the gelling agent is sodium or potassium stearate.

8. A deodorant stick as claimed in any of the preceding Claims, wherein the polyhydric alcohol constitutes 20 to 90% propylene glycol, and the gelling agent constitutes about 2 to 1 5% by weight of the stick.

9. A deodorant stick as claimed in any of the preceding Claims further comprising up to 10% by weight of a suspending agent dispersed in the soap based gel.

1 0. A deodorant stick as claimed in Claim 9 which contains an alkali metal bicarbonate powder having a particle size of about 5 to 100 microns and from 0.1 to 10% by weight of suspending agent which is colloidal silica, colloidal alumina, colloidal magnesium alumina silicates, a finely divided hydrophobic clay, or a mixture thereof.

11. A deodorant stick as claimed in Claim 10. wherein the clay used is a hydrophobically treated reaction product of bentonite or hectorite.

12. A deodorant stick as claimed in any of the preceding Claims containing a finely divided particulate water-absorptive filler material in combination with the bicarbonate powder in an essentially anhydrous soap gel.

1 3. A deodorant stick as claimed in Claim 12, wherein the filler material is talc or cornstarch.

1 4. A deodorant stick as claimed in any of the preceding Claims, wherein the alkali metal bicarbonate is formed in situ simultaneously with the alkali metal stearate soap by reacting the stearic acid with alkali metal carbonate.

1 5. A deodorant stick substantially as described herein with reference to Examples 2 to 5, 7 to 9, 12to 14 or

16 to 18.

1 6. A method of producing a deodorant stick as claimed in any of the preceding Claims wherein an aqueous dispersion or solution of an alkali metal bicarbonate is added to a hot or heated solution of a polyhydric alcohol, a saturated C14 to C20 fatty acid and an alkali metal hydroxide, pouring the warm liquid into moulds and cooling to room temperature.

1 7. A method of producing a deodorant stick as claimed in any of Claims 1 to 1 5 wherein powdered bicarbonate is added directly to the hot liquid soap based gel, pouring the warm liquid into moulds and cooling to room temperature.

18. A method of producing a deodorant stick as claimed in any of Claims 1 to 1 5 wherein a C14 to C20 fatty acid is reacted with an alkali metal carbonate to form the soap base and the alkali metal bicarbonate in situ.

1 9. A method of producing a deodorant stick as claimed in any of Claims 1 to 1 5 wherein an alkali metal soap is dissolved in hot polyhydric alcohol, the bicarbonate is added and the resultant mixture poured into containers to cool and solidify.

20. A method of producing a deodorant stick substantially as described herein with reference to Examples 2 to 5,7,11,12, and 18, or Examples 8,9,13 13 and or Example 17.

21. A deodorant stick which has been produced by the method of any of Claims 16 to 20.