Stable aerosol shaving foams containing mineral oil

Abstract

A shaving cream composition packaged in a pressure container comprising an emulsion system characterized by good foam stability when discharged from the container said emulsion comprising from 4 to 16% by weight of sodium, potassium and/or alkylolamine soaps of fatty acids, 1 to 6% by weight of emulsifiers of the class of sorbitan esters of fatty acids, 0 to 4% by weight of an amide, 5 to 25% by weight of mineral oil and the balance composed of auxiliary emulsifiers, stabilizers, surfactants, perfume and water.

Description

BACKGROUND OF THE INVENTION

This invention relates to pressurized shaving cream compositions which provide relatively stable aerosol shaving foams having improved lubricating properties. More particularly, this invention relates to a foam concentrate in a pressure container which concentrate when discharged produces stable, rigid shaving foams characterized by good lubricating properties as well as persisting throughout the shaving operation.

While aerosol shaving creams having been popular for the past twenty years, these compositions have been the subject of continuing research in order to improve their characteristics, particularly foam characteristics, and overcome consumer dissatisfactions. For example, much effort has been expended on improving the lubricating properties of the lathers so as to protect the face and speed the shaving operation. In the course of these efforts, a wide variety of additives for the shaving cream compositions have been proposed and tested. For instance, polysiloxanes have been added in amounts of up to 5% by weight to enhance lubricity. Similarly, up to 5% of water-soluble polymeric materials such as polyvinylpyrrolidone, polyacrylamide, carboxymethylcellulose, polyethylene oxide, and copolymers of acrylic acid and polyallyl sucrose have been employed for the same purpose. Additionally, oily materials such as lanolin, lanolin fractions, petrolatum, mineral oil, fatty acids, fatty alcohols, etc. have been added to shaving creams in varying amounts from about 0.5% up to about 20% by weight for a variety of reasons including lubrication.

In the preparation of the prior art emulsions as heretofore described, it is the preferred practice in preparing concentrate emulsions to add lipophilic emulsifiers to the oil phase and hydrophilic emulsifiers to the water phase. The water phase is then added to the oil phase such procedures as described by W. C. Girffin in Sagarin, Cosmetic Science and Technology p. 1025 (1957) as well as in Sanders, P. Aerosol Emulsion Foams J. Soc. Cos. Chem. Vol. 24, No. 10, P. 637, September, 1973.

Alternatively, the oil phase may be added to the water phase, but in all cases, a lipophilic emulsifier is added to the oil phase and a hydrophilic emulsifier is added to the water phase.

In preparing the compositions of the prior art following the conventional compounding methods, the foams obtained upon extrusion of the emulsion from the aerosol container are generally characterized by a soft watery consistency. It is often necessary to subject the container to vigorous and prolonged shaking in order to obtain a suitable foam for shaving. This has been found to be particularly true in the case of concentrates containing mineral oil. The latter not only tend to yield weak and unstable foams when extruded from the container, but in addition when propellant is being added during the filling operation the emulsions tend to separate, giving different lather properties depending on how hard the container is shaken before use.

It has now been found that pressurized shaving cream compositions, containing emollient materials, and which have improved lubricating qualities and relatively good emulsion stability are obtained when such shaving cream compositions include as emulsifiers sorbitan esters of fatty acids having an HLB of 1-9. In addition ethers of oleyl alcohol and ethylene oxide which have a similar HLB are also suitable.

DESCRIPTION OF THE INVENTION

The shaving cream compositions of the present invention comprise from about 4 to 16% by weight of a water-soluble soap selected from the group comprising sodium, potassium, ammonium and alkylolamine soaps of fatty acids containing 8 to 24 carbon atoms; from about 1 to 6% by weight of a sorbitan emulsifier of the class of sorbitan esters of fatty acids and ethers of oleyl alcohol and ethylene oxide having an HLB of 1-9; and from about 10 to 20% of an emollient material such as mineral oil.

The preferred compositions of the present invention are a blend of:

a. Sodium and/or potassium and alkylolamine soaps of fatty acids varying in chain length from 8-22 carbon atoms. The total soap level may vary from 4 to 16% by weight. The ratio of alkali to triethanolamine bases is not critical to this invention.

b. Emulsifiers of the class of sorbitan esters of fatty acids having an HLB of 1-9. Particularly sorbitan esters of oleic acid having an HLB of 1.8-5.0 are suitable. Ethers of oleyl alcohol and ethylene oxide which have similar HLB are also suitable. The sorbitan emulsifiers are present in amounts of from 1 to 6% by weight, preferably 4 to 5% by weight.

c. Amides of lauric acid with diethanolamine made according to the Kritschevsky process or by reacting methyl laurate with diethanolamine. The amides are present in amounts of from 0 to 4% by weight.

d. Mineral oil of Saybolt viscosities of 48-364 universal seconds at 100.degree.F. The mineral oil, which is present in amounts of from 5 to 25% by weight, must be of cosmetic, NF or USP grade.

e. The balance of the formulations is composed of auxiliary emulsifiers such as gums, polyvinylpyrrolidone or similar stabilizers of other surface active agents of the class of ethoxylated fatty acid esters or ethers and ethoxylates of sorbitan fatty acid esters, perfume and water.

Table 1 which follows sets out ten specific examples of the novel compositions of the present invention.

Additional ingredients which are compatible with the described shaving cream compositions can also be added to modify or enhance the properties thereof as desired. For example, up to about 4% of an amide of a C.sub.8 -C.sub.18 fatty acid as well as minor proportions of 0.5 to 3% by weight of water-soluble synthetic anionic, amphoteric or nonionic wetting agents such as lauryl sulfate salts, higher alkyl substituted imidazolinium salts can be included to further modify lather characteristics. In addition small amounts of water-soluble polymeric materials such as polyvinylpyrrolidone, polyacrylamide, carboxymethyl cellulose etc. and humectants such as glycerin, propylene glycol, sorbitol and polyethylene glycols can be added. Also, minor amounts of various adjuvants such as water-soluble and water-insoluble germicides, coloring agents, sequestering agents, menthol, and corrosion inhibitors such as silicates, phosphates, etc. may be incorporated in the compositions.

The propellant used in the inventive compositions can be any liquefied, normally gaseous, hydrocarbon or halogenated hydrocarbon or mixture thereof which is effective to provide a pressure in the range of about 30 to 70 p.s.i.g., preferable 40 to 55 p.s.i.g., in the ultimate container.

TABLE 1 __________________________________________________________________________ EXAMPLES 1-10 __________________________________________________________________________ INGREDIENT 1 2 3 4 5 6 7 8 9 10 __________________________________________________________________________ Stearic Acid, Triple Pressed, Flake OR 7.63 7.63 7.63 7.63 7.63 7.63 8.63 7.63 7.63 7.63 Stearic Acid, Emersol 132 Lily, Flake Stripped Coconut Fatty Acid 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 -- Potassium Hydroxide (45%) 2.32 2.32 2.32 2.32 2.32 2.32 2.32 2.32 2.32 2.32 Sodium Hydroxide, Beads 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 Glycerin, U.S.P. 3.99 3.99 3.99 3.99 3.99 3.99 3.99 3.99 3.99 3.99 Triethanolamine, N.F., (85%) 1.17 1.17 1.17 1.17 1.17 1.17 1.17 1.17 1.17 1.17 Light Mineral Oil, N.F. 13-16 centi- stokes 14.00 14.00 14.00 14.00 14.00 -- 14.00 14.00 14.00 14.00 Lauramide DEA 2.00 2.00 2.00 2.00 -- 2.00 2.00 -- 2.00 2.00 Polyvinylpyrrolidone (PVP-K-30) 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 Perfume 33.269/B/NY 0.46 0.46 0.46 0.46 0.46 0.46 0.46 0.46 0.46 0.46 Sorbitan Sesquioleate (Arlacel 83)ICI 4.64 -- -- -- 4.64 4.64 4.64 -- 4.64 4.64 Deionized Water 55.39 55.39 55.39 55.39 55.39 55.39 55.39 55.39 55.39 55.39 Propellant Mix "0" (P12/P22:90.8%/9.2%) 7.15 7.15 7.15 7.15 7.15 7.15 7.15 7.15 -- -- Sorbitan Monolaurate -- 4.64 -- -- -- -- -- -- -- -- Sorbitan Monopalmitate -- -- 4.64 -- -- -- -- -- -- -- Sorbitan Monostearate -- -- -- 4.64 -- -- -- -- -- -- Superamide L-9C (Onyx Oil and Chem.) -- -- -- -- 2.00 -- -- -- -- -- Mineral Oil, USP 38-41 centistokes -- -- -- -- -- 14.00 -- -- -- -- Polyoxyethylene (2) oleyl ether -- -- -- -- -- -- -- 4.64 -- -- n-propane -- -- -- -- -- -- -- -- 7.15 7.15 Lauric Acid (95% min. purity) -- -- -- -- -- -- -- -- -- 0.85 TOTAL 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 __________________________________________________________________________

The well known C.sub.3 -C.sub.4 hydrocarbons as well as the chlorofluorinated C.sub.1 -C.sub.2 hydrocarbons are suitable propellants because they are odorless, non-toxic and exhibit minimal skin irritation tendencies. The propellant may also be formed of a mixture of two or more such compounds. Suitable propellants include dichlorodifluoromethane (CCl.sub.3 F), dichlorotetrafluoroethane (CClF.sub.2 CClE.sub.2), monochloropentafluoroethane (CClF.sub.2 CF.sub.3), dichloromonofluoromethane (CHCl.sub.2 F), monochlorodifluoromethane (CHClF.sub.2), monochlorodifluoroethane (CH.sub.3 CClF.sub.2), trichlorotrifluoroethane (C.sub.2 Cl.sub.3 F.sub.3), and difluoroethane (CH.sub.3 CHF.sub.2). Preferred propellants are propane, dichlorodifluoromethane and mixtures of dichlorodifluoromethane and dichlorotetrafluoroethane.

As indicated above, the proportion of propellant must be sufficient to provide the desired pressure within the container. Generally, the propellant will be present in an amount of from 1 to 15% by weight of the composition, and preferable about 2.5 to 8% by weight. After giving effect to the known vapor-reducing effects of the oily material such as mineral oil, the proportion of propellant or propellant mixture can be readily ascertained by calculation. Moreover, the propellant level depends greatly upon the molecular weight and density of the particular gas used.

Further improvements in the handling properties of the emulsions present in the invention are attained when the novel method of formulation disclosed in copending application Ser. No. 456,237 filed concurrently herewith is employed. This process allows the formulations, such as exemplified by Examples 1-10 to remain reasonably fluid (200-2,000 cps.) at the point of aerosolization and at room temperature. Thus, the emulsions are easy to handle during manufacturing and filling as well as during pressuring. Normally the concentrates of the present invention are prepared by adding lipophilic emulsifiers to the oil phase and hydrophilic emulsifiers to the aqueous phase. The water phase is then added to the oil phase. It has been found that by following the process of said copending application when the mineral oil phase is added as the last essential ingredient, at the end of the soap formation, just before cooling and before adding the perfume, a much thinner lotion is obtained which can be easily handled during processing and aerosolization.

The novel compositions of the present invention as exemplified by Examples 1-10 are prepared as follows:

The polymeric material such as polyvinylpyrrolidone is admixed with deionized water in a processing kettle equipped with a large and small mixer both operated at high speed, after the polyvinylpyrrolidone is completely dispersed and the mixture lump free, the mixers are slowed and the following ingredients added in the order indicated:

1. Humectant i.e. glycerin -- if required

2. Potassium hydroxide and/or sodium hydroxide

3. Triethanolamine

The mixers are again operated at high speed and stearic acid is slowly added at a rate designed to easily disperse the acid and prevent clumping, upon complete dispersion of the stearic acid the batch is heated to 60.degree. .+-. 2.degree.C and additional water is added when the batch temperature reaches approximately 60.degree.C the following ingredients are added in the order indicated:

1. Coconut fatty acid or equivalent

2. Lauric diethanolamide if required

The batch is then heated to 80.degree. .+-. 2.degree.C and held at this temperature for a period of time sufficient to melt all waxes. While the batch is mixed. A sorbitan oleate is then added and the batch mixed for an additional 5 minutes maintaining the temperature at 80.degree. .+-. 2.degree.C. While maintaining the temperature of the mixture, mineral oil is then added at a uniform rate over a 5 minute period. After all of the mineral oil has been added the batch is held at 80.degree. .+-. 2.degree.C for approximately 10 minutes and the batch is then pumped from the kettle and cooled to 23.degree. .+-. 3.degree.C, perfume is added and the entire batch mixed until of a uniform consistency being careful not to aerate the batch.

In some of the examples, notably No. 4 all or part of the sorbitan oleate may be premixed with the mineral oil. This component is then added at the point where mineral oil would normally be incorporated as described above.

The compositions of the present invention prepared in the manner as hereinabove described are readily adapted for use in conventional aerosol dispensers now in use in a manner well known to those skilled in the art.

The foams obtained from the concentrates of the present invention exhibit desired wetting action while at the same time lubricating the face so that a minimal razor drag is experienced. Additionally, the lather serves to deposit an oil film on the skn and thus leaves the face smooth and in non-irritated condition.

Claims

What is claimed is:

1. An aqueous soap emulsion suitable for aerosolization comprising about 4 to about 16% by weight of a water-soluble soap selected from the group consisting of sodium, potassium, ammonium, an alkylolamine soap of a fatty acid and mixtures thereof, from 3 to 6% by weight of an emulsifier selected from the group consisting of a sorbitan ester of a fatty acid and a polyoxyethylene oleyl ether having an HLB of 1-9 and from 5 to about 25% by weight mineral oil.

2. The soap emulsion in accordance with claim 1 which also includes up to about 4% by weight of an amide of lauric acid with diethanolamine.

3. The soap emulsion in accordance with claim 1 wherein said emulsifier is a sorbitan ester having an HLB of 1-9.

4. The soap emulsion in accordance with claim 3 wherein said sorbitan ester is a srobitan ester of oleic acid having an HLB of 1.8 to 5.0.

5. An aerosol shave cream package comprising a valve-controlled pressure-tight container containing from 1 to 15% of a liquefied propellant gas and the balance being the soap emulsion of claim 1.

6. The aerosol shave cream package in accordance with claim 5 wherein said emulsion includes from 1 to 6% by weight of said sorbitan ester.

7. The shave cream package of claim 6 wherein said sorbitan ester is present in an amount of from 4 to 5% by weight.

8. The shave cream package of claim 7 wherein said sorbitan ester is sorbitan sesquioleate.

9. The shave cream package of claim 7 wherein said sorbitan ester is sorbitan monolaurate.