Bicarbonate-Containing Deodorant Cosmetic Stick Compositions

The subject matter of this patent application is related to that disclosed in copending patent application Ser. No. 08/503,939, filed Jul. 19, 1995; Ser. No. 08/526,269, filed Sep. 13, 1995; and Ser. No. 08/655,140, filed May 30, 1996.

Numerous solid antiperspirant and/or deodorant compositions have been described in the chemical and cosmetic literature. These compositions generally are emulsion sticks or suspensoid sticks. Emulsion sticks contain a solution of the antiperspirant ingredient incorporated into the stick via an emulsion. Although emulsion sticks are desirable in certain respects, they tend to be unstable, exhibit tackiness, and leave a visible residue on the skin after use. Suspensoid sticks contain the powdered antiperspirant ingredient suspended in the stick without the use of water or an emulsion. While suspensoids have stability, they tend to leave a white chalky residue on the skin after application.

With respect to deodorant activity, sodium bicarbonate has long been recognized for its deodorant properties, and has commonly been used as a household deodorant. Plain powdered sodium bicarbonate, or sodium bicarbonate diluted with talc or other filler, has been used as an underarm deodorant as disclosed in U.S. Pat. No. 4,382,079. Other publications which describe cosmetic stick compositions containing a bicarbonate deodorant include U.S. Pat. Nos. 4,822,602 and 4,832,945.

However, the development of a practical and effective composition in cosmetic stick form which has a deodorization capacity, and which is capable of consumer acceptability, presents many factors which are unique. Because sodium and potassium bicarbonate have only limited solubility in water, alcohol and other solvents, the preparation of a composition suitable for dispensing in cosmetic stick form has involved many processing obstacles. In addition to the problem of limited solubility, sodium bicarbonate often is incompatible with other ingredients of conventional stick compositions. Also, the dimensional stability of the cosmetic stick containing sodium bicarbonate, and the esthetic appearance and the "feel" on the skin, are just a few of the additional difficulties encountered in the preparation of a low residue deodorant cosmetic stick product.

A recent trend is toward the development of cosmetic sticks which have light transmitting properties, i.e., the cosmetic sticks are translucent or transparent in light transmitting properties, and engender a perceived appearance of purity.

Cosmetic sticks which are soap-based and which have a content of sodium bicarbonate as a deodorant ingredient typically are opaque in appearance. U.S. Pat. No. 4,440,742 describes anhydrous and water-based deodorant cosmetic sticks which contain sodium bicarbonate, and which vary from opaque to transparent in appearance as determined by the proportions of sodium bicarbonate and water, in combination with other ingredients.

There are difficulties associated with the preparation of water-based cosmetic stick products which contain sodium bicarbonate as a deodorant ingredient. Thus, the transparency properties do not have long-term stability. Acceptable degrees of hardness and smoothness are not readily achieved, and an unpleasant cool-wetness is experienced when the cosmetic stick is applied to a skin surface.

There is continuing interest in the development of water-based deodorant cosmetic stick products which have a high degree of consumer acceptance.

Accordingly, it is an object of this invention to provide a cosmetic stick product which is a water-based composition having an effective deodorizing content of particulate alkali metal bicarbonate salt.

It is another object of this invention to provide a bicarbonate salt-containing deodorant cosmetic stick product having stable transparency and affording a comfortable dry feel when applied to a skin surface.

Other objects and advantages of the present invention shall become apparent from the accompanying description and examples.

One or more objects of the present invention are accomplished by the provision of a deodorant cosmetic stick product with transparency which comprises (1) about 0.1-8 weight percent of alkali metal bicarbonate ingredient, (2) about 40-70 weight percent of polyhydric alcohol ingredient, (3) about 1-8 weight percent of hydrophilic polyoxyalkylene block polymer clarifier-surfactant ingredient, (4) about 2-8 weight percent of C.sub.14 -C.sub.22 fatty acid salt ingredient, and (5) about 10-80 weight percent of water; wherein the deodorant stick product has a penetration value between about 2.0-8.0.

The alkali metal bicarbonate ingredient is selected from sodium bicarbonate and potassium bicarbonate and mixtures thereof. The bicarbonate salt is dispersed in the cosmetic stick solid matrix in the form of fine particles. The bicarbonate can have an average particle size between about 10-150 microns, and typically is in the range between about 20-100 microns. The bicarbonate salt also can be in the form of encapsulated particles, such as with a coating of a xanthan gum hydrocolloid type polymer.

The bicarbonate-salt functions as a deodorant-active ingredient when a cosmetic stick is applied to underarm skin. The bicarbonate salt ingredient combats malodors by absorbing the objectional byproduct resulting from bacterial degradation of perspiration constituents.

The transparency of an invention cosmetic stick product is directly dependent on the proportions of dissolved and undissolved bicarbonate salt in the cosmetic stick matrix. When a cosmetic stick has a content of about 3 weight percent of bicarbonate salt, the cosmetic stick is translucent when the water content of the cosmetic stick is between about 20-50 weight percent. Depending on the content of other ingredients which can function as clarifying agents, the cosmetic stick is essentially transparent when the water content of the cosmetic stick is between about 50-80 weight percent.

The term "transparency" as employed herein refers to invention cosmetic stick products which have translucent or transparent light transmitting properties.

The term "transparent" refers to a clear body which has the property of transmitting light without appreciable scattering, so that objects beyond are entirely visible.

The term "translucent" refers to a body which is partly transparent. The body admits and diffuses light, so that objects beyond cannot be clearly distinguished.

The term "opaque" refers to a body which is impervious to visible light. An opaque body lacks any degree of transparency.

The polyhydric alcohol ingredient is selected from organic compounds which contain about 2-6 carbon atoms, and about 2-6 hydroxy groups. Illustrative of polyhydric alcohols are ethylene glycol, propylene glycol, trimethylene glycol, butylene glycol, diethylene glycol, dipropylene glycol, glycerin, sorbitol, and the like, and mixtures thereof. Preferred polyhydric alcohols are those which are water-miscible in all proportions such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and glycerin.

An essential aspect of a present invention cosmetic stick product is a content of a hydrophilic clarifier-surfactant ingredient. The clarifier-surfactant ingredient is selected from specific structural types of hydrophilic polyoxyalkylene block polymers. Suitable polymers include poloxomers corresponding to the formula: ##STR1## where x has an average value between 2-98, y has an average value between 16-67, and z has an average value between 2-98.

Other suitable polymers include poloxamines corresponding to the formula: ##STR2## where x has a value between 4-22, and y has a value between 3-122.

The term "hydrophilic" as employed herein refers to a water-dispersible polyoxyalkylene block polymer ingredient which has a water-solubility of at least about two grams per one hundred grams of water at 25.degree. C.

Illustrative of hydrophilic polyoxyalkylene block polymer clarifier-surfactants are commercial products such as Hodag Nonionic 1031-L (Hodag), Synperonic PE/F38 (ICI Americas), Chemal BF-261 (Chemax), Pluracare/Pluronic L-64 (BASF), Hodag Nonionic 1084-P (Hodag), Chemal BP-2101 (Chemax), Pluracare/Pluronic P-103 (BASF), Synperonic PE/L121 (ICI Americas), Macol 27 (PPG/Mazer), Tetronic 304 (BASF), Synperonic T/701 (ICI Americas), Tetronic 704 (BASF), Synperonic T/908 (ICI Americas), Tetronic 1307 (BASF), Tetronic 1508 (BASF), and the like; and similar hydrophilic poloxomer and poloxamine polymers as listed in the CFTA International Cosmetic Ingredient Dictionary (Fourth Edition), incorporated by reference.

The chemical structure and physical properties of hydrophilic Pluronic and Tetronic surfactants are described in a Technical Bulletin published by BASF Specialty Products (1989), incorporated by reference.

The clarifier-surfactant ingredient can comprise a single ingredient such as Pluronic F-127 (BASF) of Tetronic 1307 (BASF), or it can be in admixture with one or more other poloxomers or polyoxamines. In another embodiment, the polyoxyalkylene block polymer clarifier-surfactant is blended with between about 0.5-60 weight percent of another hydrophilic clarifier-surfactant, based on the total clarifier-surfactant weight. Dimethicone copolyol is a preferred type of optional hydrophilic clarifier-surfactant ingredient.

The hydrophilic clarifier-surfactant ingredient contributes important advantages to a present invention cosmetic stick product. The clarifier-surfactant ingredient enhances the transparency of the cosmetic stick, and stabilizes the degree of clarity over an extended period of six months or longer under normal storage and usage conditions.

The clarifier-surfactant ingredient has a gelling effect, and increases the hardness of the cosmetic stick. The clarifier-surfactant ingredient also functions as a compatibility enhancing agent, which improves the homogeneity of the diverse inorganic and organic constituents in the solid matrix.

Other advantages of the clarifier-surfactant ingredient are apparent when an invention cosmetic stick product is applied to an underarm skin area. There is ease and smoothness of application, because of the physical glidability of the clarifier-surfactant ingredient. There is an improvement in other esthetic values as well, such as a reduction in the unpleasant cool-wetness typical of cosmetic stick usage. The clarifier-surfactant ingredient also is a contributing factor to the absence of a visually perceptible residue as characteristic of a present invention cosmetic stick product after application.

A present invention cosmetic stick product includes a hardener ingredient, which preferably is selected from C.sub.14 -C.sub.2 fatty acid salts. Suitable fatty acid salts include alkali metal, alkaline earth metal, aluminum, ammonium and amine salts of fatty acids such as myristic, palmitic, stearic, behenic, oleic, linoleic, linolenic, and the like, and mixtures thereof. Illustrative of specific fatty acid salts are sodium stearate, potassium stearate, aluminum monostearate, sodium oleate, sodium palmitate, sodium behenate, diethylamine stearate, triethylamine stearate, triethylamine oleate, and the like.

A present invention cosmetic stick product can contain one or more optional ingredients such as clarifying agents, bacteriostats, antiperspirants, fragrances, colorants, and the like.

Between about 0.5-5 weight percent of a clarifying agent can be included as an optional ingredient. Suitable clarifying agents include Pentadoxynol-200 (RTD Chemicals Corp.), tetra(hydroxypropyl)diamine (Quadrol, BASF), 2-amino-2-methylpropanol (AMP, Angus Chemical Company), 2-amino-2-hydroxymethyl-1,3-propanediol (Tromethamine, Sigma Chemical Company), and the like.

Between about 0.01-0.5 weight percent of a bacteriostat can be included as an optional ingredient. The bacteriostat functions as a deodorant by preventing bacterial generation of malodorous degradation byproducts from perspiration. Typical bacteriostatic compounds include Triclosan (Ciba-Geigy), Chloracel (Reheis Chemical Company), zinc phenolsulfonate, dichloro-m-xylenol, sodium N-lauroyl sarcosine, and the like.

Between about 0.1-3 weight percent of a fragrance can be included as an optional ingredient. The selected fragrance ingredient is one which does not adversely affect the clarity of the cosmetic stick product, and preferably which contributes an odorant masking effect. Fragrances typically are organic compounds of specific type structures, which include phenolic materials, essential oils, synthetic oils, aldehydes and ketones, polycyclic compounds, esters, and alcohols. Specific fragrances are illustrated by linalyl acetate, isopropyl myristate, cedryl acetate, myrcenyl acetate, and other compounds such as those listed in U.S. Pat. No. 5,114,717; incorporated by reference. The fragrance ingredient can be encapsulated with a film-forming polymer such as polyvinyl acetate.

A present invention deodorant cosmetic stick product can be produced by blending the ingredients in a prescribed order of addition.

In a general procedure, the clarifier-surfactant and optional ingredients are added to propylene glycol with heating to form a solution. The propylene glycol solution then is blended with an aqueous sodium bicarbonate solution at about 90.degree. C. to form a homogeneous liquid medium. The warm liquid medium is poured into molds, and the molded units are cooled to room temperature to form rigid structures.

The hardness of a present invention cosmetic stick can have a value which varies in the range between about 2.0-8.0, and preferably is in the range between about 2.3-3.3.

The penetration values (in millimeters) of the cosmetic stick products described herein are measured with a Universal Penetrometer, Model TS-73510 AN-2 (Precision Scientific Inc.).

The penetration values are obtained by following a standardized procedure in accordance with ASTM Method D217-94.

The following examples are further illustrative of the present invention. The components and specific ingredients are presented as being typical, and various modifications can be derived in view of the foregoing disclosure within the scope of the invention.

This Example illustrates the preparation of a translucent deodorant cosmetic stick product in accordance with the present invention.

The sodium bicarbonate is dissolved in the water with heating to form an aqueous solution.

The triclosan and Poloxomer 407 are added to the propylene glycol, and the mixture is heated to 90.degree. C. The Part 3 ingredients are added to the propylene glycol, and heating at 90.degree.-105.degree. C. is maintained until a solution is formed.

The propylene glycol solution and aqueous solution are blended, and the colorant and fragrance ingredients are blended with the liquid medium (65.degree.-70.degree. C.).

The fluid blend is poured into Plastek 2 oz. bottom-fill cosmetic stick containers. The container contents are cooled to a room temperature solid stick over a period of 45 minutes. The solid stick is translucent in light transmitting appearance, and has an average hardness value of 2.4 millimeters (ASTM Method 217-94).

This Example illustrates the preparation of a translucent deodorant cosmetic stick product in accordance with the present invention.

The sodium bicarbonate is dissolved in the water with heating to form an aqueous solution.

The triclosan and Poloxomer 407 are added to the propylene glycol, and the mixture is heated to 90.degree. C. The Part 3 ingredients are added to the propylene glycol, and heating at 90.degree.-105.degree. C. is maintained until a solution is formed.

The propylene glycol solution and aqueous solution are blended, and the colorant and fragrance ingredients are blended with the liquid medium (65.degree.-70.degree. C.).

The fluid blend is poured into Plastek 2 oz. bottom-fill cosmetic stick containers. The container contents are cooled to a room temperature solid stick over a period of 45 minutes. The solid stick is translucent in light transmitting appearance, and has an average hardness value of 2.6 millimeters (ASTM Method 217-94).

This Example illustrates the preparation of a transparent deodorant cosmetic stick product in accordance with the present invention.

The ingredients are blended in the manner described in Example I to form a batch of packaged cosmetic stick products.

The solid stick is transparent in light transmitting appearance, and has an average hardness value of 2.9 millimeters (ASTM Method D217-94).

This Example illustrates the preparation of a translucent deodorant cosmetic stick product in accordance with the present invention.

The ingredients are blended in the manner described in Example I to form a batch of packaged cosmetic stick products.

The solid stick is transparent in light transmitting appearance, and has an average hardness value of 2.8 millimeters (ASTM Method D217-94).

This Example illustrates the preparation of a transparent deodorant cosmetic stick product in accordance with the present invention.

The ingredients are blended in the manner described in Example I to form a batch of packaged cosmetic stick products.

The solid stick is transparent in light transmitting appearance, and has an average hardness value of 3.1 millimeters (ASTM Method D217-94).