US 3541581 A
Description (OCR text may contain errors)
Nov. 17, 1970 J. A. MONSON 3,541,581
PACKAGE CONTAINING A POST-FOAMING GEL Filed Nov. 13. 1967 4 Sheets-Sheet 1 FLOW CURVES OF POST FOAMING GELS REVOLUTIONS l I PER MINUTE (Rate of shear) O 5 IO I5 20' 25 DIAL READINGS (Shear stress) JAMES A. MO'NSON INVENTOR.
PACKING 4 Sheeizs sheet 2 Filed Nov: 15, 12 E6 5:
E M m WENTOR.
A POST?? Filed Novl mwwmw 1N VENTOR United States Patent 3,541,581 PACKAGE CONTAINING A POST-FOAMING GEL James A. MOIISOI], Racine, Wis., assignor to S. C. Johnson & Son, Inc., Racine, Wis. Filed Nov. 13, 1967, Ser. No. 682,479 Int. Cl. Clld 17/04 US. Cl. 252-90 23 Claims ABSTRACT OF THE DISCLOSURE A package equipped with suitable dispensing means containing a stable post-foaming gel which can be dispensed from the package substantially free from foaming. After being dispensed, the gel will remain substantially free from foaming under static ambient conditions. Under appropriate conditions, the gel will produce a lather having a substantially uniform foam profile suitable for shavmg.
FIELD OF INVENTION Prior to the present invention, personal care preparations employed to produce lathers for shaving, shampooing, and other washing or cleansing operations included soaps which could be whipped into a lather, brushless creams, and aerosol lathers.
Personal care soaps are available today in solid, powdered, liquid, or cream form which can be whipped up into a lather by agitation, sometimes with the aid of a brush or other whipping device, as in preparing shaving lather; sometimes by agitation with the hands, as in shampooing; and sometimes by agitation with Water in preparing the lather for other washing operations. These lathering soaps were considered time-consuming and somewhat inconvenient, particularly for shaving purposes; and as a result, brushless shave creams were introduced to obviate the shortcomings of such lathering operations.
Brushless creams, which are typically modified vanishing creams, are spread upon the face in the state that they are purchased and generally do not form a lather. They are somewhat greasy or salve-like in texture and tend to adhere to the skin. The heavy texture or high viscosity of these creams makes them generally less desirable than the light and more readily removable soap lathers, particularly for the reason that the creams do not permit as close or smooth a shave and, unless thoroughly rinsed off, tend to leave a greasy or sticky feeling on the skin.
Shaving preparations packaged in aerosol containers, such as described in US. 2,655,480 to Spitzer et al., characteristically form a lather as the composition is released from the aerosol container. This lather is applied directly to the skin or hair. Aerosol lathers were first introduced in about 1950 and gained popularity quickly, probably because of such inherent advantages as ease of dispensing for application to the face, curtailment of waste, and minimal clean-up after use. Despite their popularity, aerosol lathers have been the subject of extensive criticism by the consumer since their introduction. Lack of consumer dedication to a specific aerosol lather product and the tendency of the consumer to try new aerosol lathers that are introduced reflect at least in part some of the customer dissatisfaction with present aerosol lathers.
3,541,581 Patented Nov. 17, 1970 One shortcoming characteristic of most aerosol lathers is improper wetting of the skin surface and hair which results in an inferior shave. It has been observed that the wetting of the skin and hair obtained with aerosol lathers is achieved by the liquid present in the lather as opposed to the bubbles present. Studies have shown that the flow of liquid through the space between the lather bubbles, i.e., inter-bubble transport, is a limiting physical factor in the wetting property of aerosol lathers. Thus, the presence of bubbles, although required for shaving lubricity, actually impedes wetting of the skin and hair. Secondly, the foam profile, i.e., foam density, shear stability, and shear stiffness of most commercially available aerosol lathers has been observed to change over the life of the product. Characteristic of such'a change in foam profile is the package which initially dispenses a light billowy foam and dispenses the last portion of the package as a dense liquid cream-like foam. Many commercially available aerosol lathers are known to leave a substantial residue of shaving cream in the package when the propellent is exhausted. This residue is attributed to the internal foaming occurring inside the package when it is agitated prior to discharge and/or to product misuse.
An object of this invention is to provide a lather-producing composition that, in addition to possessing the desirable properties of prior art compositions, is characterized by being discharged as a stablegel substantially free from foaming, which gel can be spread over the skin and beard and after spreading produces a self-generating foam. Another object of the invention is to provide a lather in situ at the surface of the skin and hair. Still another object of the invention is to provide a lather producing composition with improved inter-bubble transport and which will produce improved wetting of the skin and hair. Yet another object of the invention is to provide a post-foaming gel composition which is stable and remains substantially uniform in the container over prolonged periods of storage at ambient conditions. A further object of the invention is to produce a post-foaming gel which will produce a substantially uniform foam profile. Another object of the invention is to provi a lathering composition which can be dispensed substantially in its entirety from a pressure-tight container.
In general, the above and other objects are carried out by employing a package provided with suitable dispensing means containing a composition which under ambient conditions is dispensed as a stable gel substantially free from foaming. Under suitable conditions, the dispensed stable post-foaming gel will remain substantially free from foaming and yet is capable of producing a self-generating lather suitable for shaving, shampooing, or washing. It is critical to the present invention that, when the gel is stored in a' package under ambient conditions for prolonged periods, it remains as a stable homogenous composition. Thus, the entire contents of the package is discharged as a homogeneous gel which can produce a self-generating lather having a substantially uniform foam profile. The compositions of the present invention are useful in topical applications and include cleansing as well as shaving preparations. These compositions are particularly useful when employed as soaps, shampoos, shave creams, and pharmaceutical products.
In describing the invention in detail, reference will be made to the accompanying drawing in which:
FIG. 1 is a graph illustrating the flow curve and yield values of certain post-foaming gels of the invention;
FIG. 2 is a photograph of a hair follicle treated with a commercially available aerosol lather;
FIG. 3 is a photograph of a hair follicle treated with a stable post-foaming gel if the invention;
FIG. 4 illustrates a vertical cross-sectional view of an aerosol dispenser containing a stable gel of the invention maintained separate from a normally gaseous propellent; and
FIG. 5 illustrates a vertical cross-sectional view of an aerosol dispenser containing a stable gel in the presence of a non-condensable propellent.
POST-FOAMING GEL The post-foaming gels of the invention are characterized by the following properties:
(a) They are coherent colloidal dispersions of at least four components including water, a gelling aid, soap, and a post-foaming agent;
(b) They exhibit mechanical properties characteristic of the solid state; and
(c) Both the dispersed components and the dispersion medium extend themselves continuously throughout the entire composition.
The gels of the invention have a yield value; that is, they resist flow up to a given shearing tension and behave as an elastic solid below that tension.
FIG. 1 illustrates the flow curves obtained when the post-forming gels described in Examples 14 below were subjected to viscosity measurements using a Brookfield Synchro-Electric Viscometer. The shear stress, force, applied to these gels was plotted on the abscissa as dial readings. The rate of shear was plotted on the ordinate as revolutions per minute. It is evident from the fiow curves obtained that the rate of shear did not acquire a measureable value until the shear stress exceeded a given value. This latter value is defined as the yield value of the gel. The flow curve designed L was obtained for a viscous Newtonian liquid (syrup) under the same conditions. If the curve L were extrapolated, it would intersect the abscissa and ordinate at about 0. Thus, the liquid does not have a yield value. A Brookfield Synchro-Electric Viscometer, Model LVT, No. 24585, with a No. 4 spindle with a 250 m1. beaker was used for the determinations. The samples and the viscometer were equilibrated at 63 F. for 24 hours prior to making the measurements.
For the purposes of the present invention, when the yield value of the composition is sufficiently high that it can be determined with a Brookfield Synchro-Electric Viscometer, it is considered a gel. The transistion :between the liquid and the gel state is gradual, for the purpose of the present invention those transient preparations having a determinable yield value under the conditions described above are considered gels. It is thought that the solid state properties of the gels of the invention are responsible at least in part for restraining the postfoaming agent under static ambient conditions so that the gel remains substantially free from foaming when dispensed from the package.
For the purposes of the present invention, a postfoaming gel is defined as a gel which remains substantially free from foaming for at least sixty seconds when discharged from a pressure-tight container under static ambient conditions. This property of being substantially free from foaming under static ambient conditions is illustrated in Examples 1-4 below. For the purposes of the present nivention, a gel is dispensed under static ambient conditions when it is discharged at about 63 F. at approximately one atmosphere of pressure under conditions substantially free from shearing tension.
In defining the post-foaming gel of the invention as stable, the accepted definition of the term stable is intended, i.e., not readily changing in physical state or properties. The stability of the gels of the invention can be monitored by comparing the foam profile of the gels obtained from various portions of the container. It has been found that the gels obtained from various'portions of a container have substantially uniform foam density. Foam profile includes properties such as density, stiifness, and shear stability, and is reported in Table I below.
The stability of the gels of the invention can also be monitored by chemical analysis of the gel discharged and/ or by X-raying the container periodically and noting any changes in the gel structure. Instability of the gel in the package would be evidenced by changes in foam profile, changes in gel composition, and/or separation or stratifying of the gel.
In general, gels may be formed either from solution or from a solid substance exhibiting swelling power. However, only those gels formed from solution are suitable for the purposes of the present invention. In order that a stable gel be formed from solution, the following conditions must be fulfilled.
(a) A solid substance separates from the solution in a finely dispersed colloidal state; and
(b) The separated solid particles are neither deposited by gravity nor remain in a colloidal suspension as freely moving kinetic units, but rather they join together to form a continuous coherent framework throughout the mass of the solution.
The preparation of a stable post-foaming gel of the invention is described in detail below.
Briefly summarized, the essential components of the post-foaming gel comprise a major amount of water, soap, gelling aid, and a post-foaming agent. While these components are essential to the novel compositions of the invention, other ingredients are advantageously included. Preferred components in the composition comprise:
(1) a major amount of water;
(2) soap, i.e., water-soluble salts of high molecular weight fatty acids;
(3) gelling aid, i.e., water-soluble derivatives of naturally occurring substances such as cellulose, sucrose, and glucose;
(4) a post-foaming agent, i.e., organic liquids having a vapor pressure from about 6 to about 14 p.s.i.g. at a temperature from about 90 to 100 F.; and
(5) miscellaneous additives such as humectants, foam supplements, perfumes, flavors, skin conditioners, and emollients.
The water in the compositions of the present invention is requisite for the preparation of a post-foaming gel having desirable lathering properties. It has been found that water (tap water, distilled water, deionized water, etc.) possesses adequate solubility for the soap and has the required compatibility with the gelling aid and postfoaming agents to produce stable gels of the invention. In general, relatively small amounts of polar substances, such as lower molecular weight alcohols, methanol, ethanol, propanol, isopropanol, and the like, may be used; the only requirement being that sufiicient water be present to maintain the desired physical characteristic of the gel and the foam profile of the lather as discussed below. Generally, the amount of water employed in the gel may be varied depending upon the properties desired in the final product. The amount of water employed depends on the nature of the soap and gelling aid used.
It has been found, however, that at least about 40 percent and preferably from about 50 to about percent by weight of the total gel composition should be water although higher amounts may be employed if desired, e.g., up to about percent by weight of the total composition. The upper limit is the maximum amount that produces a satisfactory gel and lather at the temperatures likely to be encountered in use, while the lower limit is fixed substantially by economic considerations.
The soap, i.e., the water-soluble salts of higher fatty acids used in accordance with the present invention are well known in the art and may be prepared in any conventional manner. For example, these soaps may be pre pared by reacting a basic material such as triethanolamine directly with a higher fatty acid such as stearic, palmitic, myristic, oleic, coconut oil fatty acids, soya oil fatty acids, and mixtures of these acids.
The nature of the soap or detergent used, although not critical, has an effect on the type of gel and lather produced. Preferred soaps include the water-soluble stearate and palmitate soaps, such as the potassium, ammonium, and soluble amine soaps of commercial stearic acid and palmitic acid. The triethanolamine and morpholine soaps of these acids are preferred. The product sold commercially as stearic acid is actually a mixture consisting primarily of stearic and palmitic acids. The term stearates is used herein to designate soaps of commercial stearic acid, although soaps of chemically pure stearic acid would be the equivalent for the purposes of this invention. The soaps may be made by neutralization of the appropriate higher fatty acid with suitable alkali, or may be introduced in the form of animal fats, such as tallow, or vegetable fats, such as palm oil, which are rich in the appropriate acid and which, when saponified, form soaps rich in the corresponding acid. Mixtures of the various soaps may be used, and small proportions, preferably less than percent, of a less Water-soluble soap, such as a sodium stearate soap, may be used with the more watersoluble soaps mentioned above to obtain the desired properties, particularly when the product is used to produce a shaving lather. Vegetable oil soaps, including the soaps of cottonseed oil, olive oil, soya oil, etc., may be used either alone or preferably in admixture with the animal fat and vegetable fat soaps described above. When the vegetable oil soaps are used alone, or as the primary soap ingredient, the resultant lather is somewhat looser, coarser, and less stable than when water-soluble animal fat and vegetable fat soaps or mixtures are employed. For this reason, when the composition is to be used for producing a shaving lather, a substantial proportion of watersoluble animal fats and vegetable fat soaps is used, whereas stable post-foaming gels of the invention useful as shampoos or washing lathers can contain a substantial proportion of vegetable oil soaps. When preparing a stable post-foaming gel suitable as a shaving lather, it is preferred that upwards of 30 percent and preferably from 60 to 100 percent of the soap used be a water-soluble stearate; the balance, if any, being a palmitate or an ordinary vegetable oil soap. When the product is to be used for shampooing or washing as opposed to shaving, a relatively loose or coarse lather may be more suitable. Such lathers can be obtained with vegetable fats and vegetable oil soaps, examples of which have been referred to above.
Certain surface active agents, usually called wetting agents, may also be used as the soap ingredient. The wetting agents so employed preferably are anionic or nonionic in character. They should be appreciably soluble in the aqueous components of the gel and of the type that produce foam in water solution. Examples of such agents are triethanolamine lauryl sulfate, sodium lauryl sulfate, sodium dodecyl benzene sulfonate, water-soluble polyoxyethylene ethers of alkyl-substituted phenols, and watersoluble polyoxyethylene cetyl ethers. Numerous anionic and nonionic wetting agents suitable for the purposes of the present invention are described in detail in McCutcheons Emulsifiers & Detergents Annual, 1967. Although not essential to the invention, in some cases it may be desirable to add minor concentrations of a wetting agent to the gel as a supplement to the water-soluble soaps described above. The wetting agent has been found to be effective in removing oily residue from the skin and in facilitating rinsing the lather from the skin. When thus added to the composition as a soap supplement, the wetting agent should be used in minor concentrations, preferably from about 0.5 percent to about 5 or 6 percent by weight of the gel.
The amount of soap employed to form the gel is not critical and generally depends upon the nature of the soap used. The low limit is the minimum amount which gives a satisfactory lather and gel, and the upper limit is fixed either by economic considerations or by the amount which will form a suitable gel at the highest temperatures likely to be encountered in use. A preferred range for all soaps employed in the novel compositions herein described should generally amount to at least about 4 percent, usually from about 5 to about 25 percent, and preferably about 8 to 12 percent of the total weight of the preparation. The beneficial effects of the instant invention are achieved to an optimum degree when the composition contains an appreciable amount of soap, such as specified within the preferred range. An aqueous soap intermediate is prepared containing the fatty acid, Wetting agents, and miscellaneous additives according to the procedure described below.
The gelling aids used in accordance with the invention are well known in the art and can be classified as watersoluble derivatives of naturally occurring substances such as cellulose, sucrose, and glucose.
Preferred gelling aids useful in the invention include:
(a) the copolymers of acrylic acid and a polyallyl sucrose; and
(b) reaction products of cellulose or glucose with acids or alkylene oxides.
These substances may be employed in concentrations as low as about 0.01 percent by weight of the total composition to provide suitable gels. They may be included in concentrations as high as about 5.0 percent to obtain gels having substantially higher yield values; however, economics generally mitigrate against such higher concentrations. Preferably, the gelling aid is used in concentrations from about 0.05 to about 1.5 percent by weight of the total composition.
Suitable sucrose derivatives are exemplified and obtainable commercially as Carbopol 9'34, Carbopol 940 and 941 (the word Carbopol is a Registered Trademark). Copolymers of acrylic acid and polyallyl sucrose and their method of preparation are described in US. Pat. 2,798,053 to Brown.
In the shaving compositions of the invention, the cellulose derivative provides superior lubrication for the shaving blade, in addition to its function as a gelling agent. Suitable cellulose derivatives are exemplified by:
(1) Sodium carboxymethylcellulose, the product of the reaction between an alkali cellulose and monochloracetic acid. A product of this type is marketed by the Hercules Powder Company under the trade names Hercules Cellulose Gum and CMC. Depending on the degree of polymerization of the cellulose and the kind and amount of substitution, the viscosity characteristic of the sodium carboxymethylcellulose may vary Widely. Thus, there are many grades available; and 2 percent aqueous solutions of the various grades will vary in viscosity from 10 to 100,000 centipoises at 25 C. or stated differently, for a solution of centipoises the percent of solids in the solution may vary from 0.3 percent for a high viscosity grade (for example, Hercules CMC7H) to 4.0 percent for a low viscosity grade (for example, Hercules CMC-JA). Any of the grades of sodium carboxymethylcellulose is suitable for use in compositions of the invention, but the higher viscosity grades are preferred in order to keep the solids content to a minimum and at the same time be in sufficient quantity to provide satisfactory lubrication. Thus, using the high viscosity grade Hercules CMC-JH, a minimum concentration of about .04 percent is required. Minimum concentrations of the other grades would-be the corresponding amounts to provide equivalent yield values in the composition. The maximum quantity of sodium carboxymethylcellulose acceptable is governed by the yield value and postfoaming properties of the gel. Using Hercules CMC7H, the maximum concentration desired in the composition is about 1 percent. Maximum concentrations of the other grades would be the corresponding amounts to provide equivalent yield values and post-foaming properties.
(b) Cellulose methyl ether, the product of the reaction between an alkali cellulose and methyl chloride is also known as methyl cellulose. A product of this type is marketed by the Dow Chemical Company under the trade name Methocel. As with sodium carboxymethylcellulose and for the same reasons, there are many viscosity grades of methyl cellulose available, and for an aqueous solution of 100 centipoises at 20 C. the percent of solids in solution may vary from 0.5 percent for a high viscosity grade (for example, Methocel, 4000 cps) to 6.0 percent for a low viscosity grade (for example, Methocel, 10 cps). Any grade of methyl cellulose is suitable for use in the composition, with the higher viscosity grades preferred. Corresponding concentrations of the other grades of methyl cellulose are those that provide equivalent viscosity in the liquid shaving composition.
Hydroxyalkyl cellulose, the product of the reaction between an alkali cellulose and an alkylene oxide, such as ethylene or propylene oxide. Products of this type are marketed under the trademarks Natrosol and Klucel. As with sodium carboxymethylcellulose, and for the same reasons, there are many viscosity grades of hydroxyalkyl celluloses. Any grade of hydroxyalkylcellulose is suitable for use in the composition of the invention, with the higher viscosity grades preferred. Using Klucel-HA, a minimum of about 0.01 percent is required and a maximum of about 0.4 percent can be used. These cellulose derivatives are described in detail in Hercules Chemist, April 1967.
Natural gums, other synthetic gums, resins, latices, starches, alcohols, and protein gel-formers generally used as thickeners in cosmetic and pharmaceutical preparations can be used at least in part as gelling aids, provided they produce stable gels having the yield values and postfoaming properties essential to the invention.
An aqueous-base intermediate of the gelling aid is usually prepared which intermediate is introduced into the soap intermediate according to the procedure described in detail below.
It is critical to the present invention that the postfoaming agent used be: non-toxic, capable of being dispersed continuously throughout the stable gel, and compatible with the other components of the gel. The vapor pressure of the post-foaming agent is also critical in that:
(1) When the gel is rubbed either between the fingers or on the skin, a lather should be produced by volatilization of the post-foaming agent; and
(2) When the gel is dispensed from the container under static ambient conditions, the gel remains substantially free from foaming for at least about 60 seconds. That is, the yield value of the gel is such that it substantially restrains the post-foaming agent from volatilizing under static ambient conditions for at least about 60 seconds.
It has been observed that the higher the vapor pressure of the gel at a given temperature, the more rapidly the lather develops. In order to provide a sufiiciently rapid development of the foam at a temperature between about 90 and 100 F., it is necessary for the vapor pressure of the gel to reach a value of from about 6 to about 14 p.s.i.g. The post-foaming agent is primarily responsible for the vapor pressure of the gel.
Certain fatty acid soaps and gelling aids suitable for use in the gel have been observed to lower the vapor pressure of the post-foaming agent. Therefore, not only the vapor pressure of the post-foaming agent but also the influence of the other substances present in the gel and the type of stable gel obtained, as indicated by its yield value, must be considered in preparing the compositions of the invention. It is desirable to prepare post-foaming gel compositions which do not exert a substantial pressure on their packages at ambient temperatures, i.e., F. When such gels are prepared, they can be packaged in flexible containers, such as conventional collapsible tubes, resulting in a substantial savings over the pressure packages used to dispense aerosol lathers.
The post-foaming agents of the invention are liquids or liquifiable and include saturated aliphatic hydrocarbons having from 4 to 6 carbon atoms, such as butanes, preferably n-butane, pentanes, and hexanes, and partially or wholly halogenated hydrocarbons, such as trichlorotrifiuoroethane (Freon 13), 1,2 dichloro, 1,1,2,2-tetrafluoroethane (Freon 114). Mixtures of these hydrocarbon and/ or halogenated hydrocarbon post-foaming agents are useful for providing the particular vapor pressure desired. For example, stable gels containing mixtures of n-pentane and n-butane have been employed in proportions ranging from about :5 to about 70:30 respectively and have been found suitable for the purposes of the present invention. An advantage of using mixtures of two or more post-foaming agents is that, although the individual agents may have vapor pressures outside the desired range, when combined in the gel, the resultant gel has a vapor pressure within the range, i.e., from about 6 to about 14 p.s.i.g. at a temperature from about 90 to about F.
When the product is used to produce shaving lather, it may de desirable to avoid the use of post-foaming agents that result in a marked tingling or burning sensation when the gel is applied to the skin. Generally, useful post-foaming agents are those substances which have very low solubility in water, i.e., less than about 20 cc. of gas in 100 grams of water at one atmosphere absolute and 70 F. The least water-soluble post-foaming agents produce little or no burning sensation on the skin.
The concentration of post-foaming agent used in the gels of the invention is critical. The type and concentration of post-foaming agent is determinative, at least in part, of certain properties of the compositions of the invention including stability, yield value, post-foaming characteristics, and foam profile.
For example, when the concentration of the postfoaming agent in one stable post-foaming gel of the invention was increased substantially by substituting additional post-foaming for a portion of the water, the resultant gel failed to retain its post-foaming properties. That is, it did not remain substantially free from foaming for at least 60 seconds when discharged from a pressuretight container under static ambient conditions. The gel was observed to have substantial foam formation directly upon'discharge from the container. A substantial increase in the concentration of post-foaming agent has also been observed to produce a decrease in foam density and affect the yield value of certain postfoaming gel of the invention.
Aliphatic hydrocarbon post-foaming agents will comprise at least about 0.5 percent and preferably from about 1 to about 4 percent by weight of the gel. Halogenated hydro-carbon post-foaming agents will comprise at least about 1 percent and preferably from about 2 to about 8 percent by Weight of the gel. Mixtures of aliphatic hydrocarbon and halogenated hydrocarbon propellants can be used provided the total post-foaming agent concentration is such that the resultant post-foaming gel has satisfactory stability, yield values, post-foaming characteristics, and foam profile.
As indicated above, the addition of various adjuvant materials to the stable gel is contemplated by the present invention. Thus, the finished compositions ordinarily will contain a humectant, such as a mixture of propylene glycol and sorbitol. Also, ingredients which impart further desired qualities to the skin during and after shaving may be incorporated in the present compositions. Thus, skin fresheners or lather stabilizers or the like, such as glycerine, lanolin, lecithin, higher alcohols, propylene glycol dipelargonate, coconut oil, and mixtures thereof, may generally be used in minor proportions. Furthermore, coloring materials, such as dyes and perfumes, may be used if desired.
Another advantageous modification of the gels of the invention is the inclusion of an agent to act as a preservative or alternatively to provide an antiseptic environment during tis use. A component of this type is common to the cosmetic industry, and many compounds are suitable for this purpose, such as chlorinated phenols, hydroxyquinoline, phenol, thymol, and hexachlorophene.
Still another advantageous modification of the gels of the invention is the inclusion of pharmaceutical additives suitable for topical application to the skin for the purpose of disinfecting the skin, minor wounds, and abrasions. Suitable additives for this purpose include benzalkonium chloride, described in US. Pat. 2,086,585 ,and US. Pat. 2,152,047; benzethonium chloride, described in US. Pats. 2,115,250 and 2,229,024; and meta cresyl acetate described in US. Pat. 1,031,971.
The stable post-foaming gels of the invention can be modified by the homogeneous dispersion therein of discrete insoluble particles such as time-release capsules, pigments, and insoluble insect repellents.
The yield value of the gel may be further controlled by the pH of the composition, the ratio of the soap to the gelling aid, and the ratio of gelling substances and other organic additives such as the humectants to the water. The yield value of the gel can be still further controlled by the nature of the alkaline ingredient of the soap, e.g., triethanolamine, diisopropanolamine, alkali metal hydroxide, depending upon the molecular size and structure of such ingredients.
FOAM PROFILE Foam profile is defined as the density, stiffness, and shear stability properties obtained when the post-foaming gels of the invention are subjected to foaming conditions. The gels of the invention will produce a substantially uniform foam density even when discharged from various portions of the container and/or after prolonged periods of storage. It is suggested that this uniformity in foam density is an indication of gel stability.
For the purposes of the present invention, foam density is defined as the ratio of the weight of foam, in grams per unit volume of the foam in milliliters. Specifically, foam density is obtained by discharging the stable postfoaming gel into the hands and rubbing the hands together to form a lather. Some of this lather is then transferred into a weighed, smooth-topped vessel of known volume (beakers from about to 30 ml. are preferred). The weight of the filled beaker is established and the density calculated. The foams of the invention preferably have densities from about 0. to about 0.5 g./ml.
For the purposes of the present invention, foam stiffness is defined broadly as the viscosity of the foam. Specifically, foam stiffness is obtained by discharging about 400 grams of the post-foaming gel under static ambient conditions into a temperature cell comprising a jacketed glass cylinder provided with a constant flow of water at a given temperature. Water at about 108 F. is passed through the jacket for about 10 minutes, during which time the gel is brought to a temperature of about 94 F. An Instron Tensile Tester (Model TT), equipped with a plexiglass piston about 2% inches in diameter, is used with the glass cylinder, which has an inside diameter of about 3 inches and a height of about 8 inches. The piston is cycled into the cylinder within 1 inch of the bottom of the cylinder at a rate of 10 inches per minute; and the force, in grams, required to drive the piston through the lather is recorded as registered by the calibrated load cell of the Tensile Tester. The Tester is cycled until a maxrnium force value is obtained. To obtain the force per unit area, the maximum value obtained is diveded by the area of the opening between the piston and the cylinder, i.e., 3.90 cm. Thus, the stiffness values are recorded in units of g./cm. The foams obtained from the post-foaming gel of the invention have stiffness' values ranging from about 20 to about g./cm.
For the purposes of the present invention, shear stability is defined as the ratio of the maximum stiffness obtained during a 30-minute cycle with the Instron Tensile Tester to the stiffness value obtained on the final stroke after a 30-minute cycle with the Instron Tensile Tester. Specifically, the procedure used in obtaining the stiffness values is as follows: The piston of the Instron Tensile Tester is cycled through the foam contained in the cylinder using a 2-inch stroke, 2 /2 cycles per minute, for a period of 30 minutes. The ratio of the maximum stiffness value obtained during this period .in g./cm. is compared with the stiffness in g./cm. obtained with the final stroke. Foams obtained from the post-foaming gels of the invention have shear stability values from about 6.8 to about 7.0. The foam profiles of certain compositions of the invention are set forth in Table I below. The foam profile of a commercially availbale aerosol lather was also determined and is discussed below.
FIGS. 2 and 3 of the drawings are photographs of hair follicles treated with a commercially available aerosol lather and a second hair follicle treated with a post-foaming gel of the invention, respectively. These photographs were taken with a dark field illumination using a Zeiss Photomicroscope Pol Microscope. Thirty-five mm. film was used. The photographs were taken at a magnification of 25X. The prints obtained were blown up to a total magnification of x by standard enlargement procedures. Standard developmnet techniques were employed. When FIG. 2 is compared with FIG. 3, the improved 'wetting obtained on the hair follicle in FIG. 3 is apparent, particularly on that portion of the follicle extending above the lather. The increased wetting obtained with the post-foaming gel of the invention is attributed at least in part to: the higher foam density and the improved inter-bubble transport. These properties are characteristic of the foams of the invention. That is, the channels between the bubbles of the composition of the invention are less restricted and interrupted by bubbles than those of aerosol lathers. This is particularly evident in the area surrounding the hair follicle in the lower half of each drawing. Thus, transport of the wetting solution through the channels to the skin and hair is more readily achieved with the post-foaming gels of the invention. In addition, the gels of the invention are applied to the skin as a thin film before foaming occurs. This film is characterized by a body or consistency which tends to hold the hair shafts erect resulting ultimately in a more thorough wetting of the hair and surrounding skin.
PACKAGE The stable post-foaming gels of the invention can be packaged in many types of containers which are commercially available, including collapsible metal tubes and aerosol dispensers. If an aerosol dispenser is employed, it is preferred that the stable post-foaming gel be maintained in the package separate from the propellent by means of a bag or diaphragm inside the package. If a diaphragm is employed, it can be driven by a propellent or a mechanical force, such as a spring. It has been observed that, if a propellant, such as isobutane, is used and is not maintained separate from the gel, at least a portion of the propellent will be absorbed into the gel and cause the gel to be dispensed with some foaming or cause premature foaming, neither of which is suitable for the purposes of the invention.
FIG. 4 illustrates an aerosol dispenser containing a stable gel maintained separate from a normally gaseous liquid propellent. Referring to FIG. 4, the package comprises a closed container 1 provided with a gel-dispensing head 2, a corrugated plastic bag 3 containing the stable post-foaming gel 4, a propellent chamber 5 containing gaseous propellent 6 provided by volatilization of a portion of the liquid propellent 7. The bag is assembled in the container and filled with the gel using standard aerosol filling techniques. Dispensing head 2 is assembled with container 1 and filled plastic bag 3 and sealed at sealing surface 8. This seal can be effected by means of a crimping action such as is achieved during the under-the-cap filling process described in US. Pat. 2,947,626 to Focht. The liquid propellent is introduced through charging port 9. Suitable packages of this type and methods of filling same are described in detail in Drug & Cosmetic Industry, August 1967, and Canadian Pat. 751,775 to Strengelbach et al.
Dispensing head 2 comprises a mounting cup having a central circular aperture formed by an upturned aperture flange 11, substantially perpendicular to wall 12 and joined thereto by radius portion 13. Penetrating the aperture defined by flange 11 and adapted for cross-sealing engagement against the inner surface of flange 11 is a tubular sleeve portion 14 with resilient sealing grommet generally designated 15 formed preferably with synthetic rubber. At the lower end of tubular sleeve portion 14 are two enlarged body portions having sealing faces 16 and 16a, adapted to seal against the inner surface of wall 12 and the outer end of aperture flange 11, respectively. In addition, scaling is also achieved against radius portion 13. Sealing face 16 is surrounded by the tapering, flexible, unsecured peripheral edge 17. The grommet 15 has a valve seal portion 18, which in closed position seals stem orifices 19 and 19a which are discussed in detail below.
The dispensing head is preferably formed of a rigid plastic by injection molding. It comprises tubular spout 20 having an annular shoulder 21 and two stem orifices 19 and 19a. Annular shoulder 21 is in sealing engagement with the upper end of sleeve portion 14. Tubular spout 20 penetrates sleeve portion 14 and seals against the lower end of sleeve portion 14 by means of valve head 22. The stable post-foaming gel of the invention is dispensed from tubular spout 20 through stem orifices 19 and/or 19a by tilting dispensing head 2 so as to displace orifices 19 and/ or 19a from valve seal portion 18. Suitable dispensing heads are described in US. Pats. 2,615,597 to Tomasek et al.; 2,704,172 to Lapin; 2,704,622 to Sofler; 2,739,841 to Sofler; 2,877,936 to Michel 2,906,449 to Focht; 3,132,774 to Solfer; 2,678,147 to Abplanalp; and 2,753,214 to Abplanalp. Other dispensing heads, such as disclosed in U.S. Pats. 2,772,819 to Poarch et al. and 3,249,261 to Benediktson, can also be employed for the purposes of the present invention.
Suitable propellents useful in pressurizing the container described above include the condensable gaseous propellents ordinarily utilized in the manufacture of aerosol compositions. For example, suitable propellents include hydrocarbon propellents, such as propane, butane, isobutane, and isopentane, and halogenated hydrocarbon propellents which can be represented by the structural formula C H Cl F wherein n is a whole number from 1 to 2 and x, y and z is equal to 2n+2.
Examples of halogenated hydrocarbon propellents include: monochlortrifluoromethane, trichloromonofluoromethane, dichlorodifluoromethane, dichloromonofluoromethane, monochlorodifluoromethane, trichlorotrifluoroethane, dichlorotetrafluoroethane, difluoroethane, and difluoromonochloroethane. Most of these halogenated hydrocarbon propellents are available commercially under trade names such as Freon and Genetron. Mixtures of various propellents and diluents are often employed to obtain the desired vapor pressure within the container. In addition to the various condensable gaseous propellents discussed above, propellents suitable for the present invention can comprise blends of the foregoing propellents with noncondensable gases such as nitrous oxide or nitrogen.
FIG. 5 illustrates an aerosol dispenser containing a stable post-foaming gel in the presence of a non-condensable propellent. Referring to FIG. 5, the package comprises a closed container 31 made of any appropriate material, provided with a gel-dispensing head 32, and containing the stable post-foaming gel 33 and a compressed gas propellent 34a in head space 34. This container has a top closure sealed by a cup 35 on which is mounted any appropriate form of valve which will dispense the gel of the invention. For the purpose of illustration, a valve, such as described in US. Pat. 2,631,814 to Abplanalp, is shown. The valve comprises a valve body having therein a valve core 36 provided with a stem 37. Said stem, which is of tubular form, has formed therein a cross-axial opening adapted, when the valve is closed, to be embraced and sealed by a resilient sealing gasket 38. A spring 39 normally moves the valve core into closed position to seal the opening 40. Attached to the lower end of the valve body is an eduction or dip tube 41 which extends to the bottom of the container.
Mounted on the upper end of the container is a dispensing cap 32 of the type described in Reissue Patent 24,555. This cap is provided with a hub 43' formed on a tab 44. The hub has a socket which receives the upper end of the valve stem 37 and from this hub extends an outlet passage 45 formed partially within the body of the cap and extending through a spout 46 projecting beyond one side thereof.
The cap shown in the drawing has heretofore been extensively used on dispersions adapted to deliver foam such for example, as aerosol shaving creams. This type of cap is well adapted to carry out the present invention when incorporated in the system of which the drawing is illustrative. For example, when downward pressure is placed on the tab 44, the valve body is depressed to open the valve as shown in the drawing so that the compressed gas propellent 34 in the head space may force the gel upwardly through the dip tube 41 and through the unsealed opening and then through the tubular valve stem into and out through the passage to be discharged from spout 46.
Suitable propellents useful for pressurizing this container include gases such as nitrogen, argon, neon, krypton, xenon, helium, and radon. Nitrogen is preferred because it is relatively inexpensive and highly effective in carrying out the purpose of the invention. It should be understood, however, that some other propellents, such as nitrous oxide and carbon dioxide, may be employed for use with the container disclosed in FIG. 5, which propellents are not entirely insoluble or inert, depending primarily upon the gel and more particularly upon the materials to be included in the gel. However, the propellent must be such that it will not cause foaming of the gel upon discharge and provided the gel retains its post-foaming properties as described above. When an inert and substantially insoluble propellent is employed, the gel which is discharged is substantially free from propellent. Under some circumstances, it would do no harm to use a propellent which is slightly soluble in the gel or at least not soluble enough to effect the post-foaming properties of the gel. Therefore, while a preferred procedure of the present invention is directed to dispensing gels substantially free from the propellent used to pressurize the package, the use of propellent which might cause the entrapment of a slight amount of gas within the gel will not depart from the invention.
The package can be further modified by the addition of a suitable heating means to the dispensing means so that the post-foaming gel can be heated prior to application to the skin. In this regard, it has been observed that an amount of gel required for one shave can be heated from room temperature to body temperature, about 98 F more efliciently than a corresponding amount of aerosol lather.
The following examples are given by way of illustration only and are not intended as limitations of this invention, many apparent variations of which are possible without departing from the spirit and scope thereof.
EXAMPLES 1-4 Four stable post-foaming shaving compositions of the invention, described in Table I below, were prepared and tested.
The stable post-foaming gel described in Example 1 in Table I below was prepared as follows:
(a) Soap intermediate; 5.8 parts of palmitic acid, 2.0 parts of stearic acid, and 1.0 part of Brij52 were mixed in a suitable beaker. 10 parts of sorbitol was mixed with a portion of the deionized water in a suitable beaker. 4.20 parts of triethanolamine was mixed with a portion of the deionized water in a suitable beaker. The three beakers were heated to about 180 F. The heated aqueous sorbitol solution was added to the heated mixture of acids and surface active agent. This mixture was allowed to stand for about 2 minutes to allow escapement of air. A small portion of the heated triethanolamine solution was introduced to the mixture with agitation, producing a creamy emulsion. The remainder of the heated triethanolamine solution was gradually added to the emulsion with agitation. The resulting soap intermediate was cooled to about 8 F. by means of a water bath and with constant agitation.
(b) Gelling aid intermediates; a 1 percent Klucel-HA intermediate is prepared as follows: 66 parts of deionized water were introduced into a 4000 ml. glass beaker and agitated by an off-set air motor with a 1 /2 inch impeller. Over a space of about 60 seconds, 1 part Klucel HA was added to the vortex created in the water under agitation. Agitation of the resultant thickened liquid was continued for approximately 20 minutes. The remainder of the water, 33 parts, was introduced into the thickened liquid and agitation continued for approximately 10 minutes. A 1.5 percent Carbopol 934 intermediate was prepared in the same manner using 1.5 percent Carbopol and 98.5 percent water. Both gelling aid intermediates were allowed to stand sufliciently long to allow for essentially complete release of the entrapped air. A Klucel- HA/propylene glycol intermediate was prepared as follows: 3.3 parts of propylene glycol and 0.325 part of an appropriate dye solution was added to 6.7 parts of the Klucel-HA intermediate. The resulting intermediate was allowed to stand sufiiciently long to allow for essentially complete release of entrapped air.
(c) Non-pressurized intermediate; 10.325 parts of Klucel-HA/propylene glycol intermediate was added slowly with agitation to a beaker containing 73 parts of the soap intermediate. An appropriate fragrance was introduced into the mixture at this time. The Carbopol 934 intermediate was then gradually added to the beaker with agitation.
(d) Post-forming agent intermediate; 10 parts of normal butane and 40 parts of normal pentane were added to 50 parts of propylene glycol dipelargonate which was being agitated in an open vessel maintained at about 40 F.
The final pressurized product is prepared by introducing 94.5 parts of the non-pressurized intermediate into a .Duralydo 4000 ml. reactor equipped with a fiat stainless baflle and a heavy duty air-driven agitator. Care is taken to avoid significant entrapment of air. The postfoaming agent intermediate is then carefully introduced into the container so that a clear layer of the post-foaming agent intermediate is formed on the top of the nonpressurized intermediate. The reactor is sealed and maintained under approximately 5 pounds of pressure. The pressure is increased to about 7 to 10 p.s.i.g.; and, after the pressure in the reactor reaches equilibrium, the reactor is agitated for about 2 minutes at about 850 rpm. The agitated mixture is then removed from the reactor which is maintained under a constant head of pressure.
Care is taken to avoid entrapping air during this operation. The mixture removed from the reactor is introduced directly into a container provided with a plastic bag such as disclosed in FIG. 4 of the drawing. A valve, such as shown in FIG. 5, is crimped into place immediately after the bag is filled. The container is pressurized through charging port 9 with about 10 ml. of a normally gaseous hydrocarbon propellent containing a mixture of propane and isobutane and having a vapor pressure of approximately 46 p.s.i.g.
The stable post-forming gels described in Examples 24 were prepared in essentially the same manner and pressurized in similar containers under the same conditions.
TABLE I Examples Component (percent by weight) Palmitic acid (95% purity) 5. 6. 50 6. 75 5. Steario acid (97% purity). 2.00 2. 25 1. 00 2.00 Ce t yl alcohoL a 1 00 1. 00 13111-52 1. 00 1. 00 sorbitol (70% solu on in water) 10.00 10. 0 10.00 7. 50 Triethanolamine 4. 20 4. 75 4. 65 1. 40 Mixed isopropanolarnines (mixture of mono-, di, and triisopropanolamines) 2. 90 Propylene glyeoL 30 3. 30 3. 30 2. 50 glued-HA 0. 075 0. 075 0. 075 ye i. .s. .s. .s. Fragrancegs. 8s. (3.5. Carbopol 934- 0. I80 0. 225 0. 225 0. Propylene glycol dlpelargonate 2. 75 2. 75 2. 25 2. 75 t 0. 55 0. 45 0.55 2. 20 1.80 2. 20 Water (deionized) 66. 4.0 68. 50 71. 045 Approximate yield value,
readings 9 9 5 9 Foam density (g./cc.) (first portion of package) 0. 33 0. 31 0. 27 0. 36 Foam density (g./cc.) (last portion of k e) O. 35 0. 32 0. 30 0. 38 29. 0 69. 8 39. 4 48. 0 0. 96 1. 00 0. 99 0.9
The above compositions were tested with and without a preliminary washing or rinsing of the face with water. The post-foaming gel was dispensed from a package such as shown in FIG. 4, applied to the skin by patting and/ or rubbing with the fingers, and after being spread on the face produced a rich lather in each instance. The observed results of the shaving tests showed only minor variations in degree of properties for all of the above samples. In all tests, application was smooth and rapid and resulted in a foam that was well adhering and nonirritating to cuts or sensitive tissues. The gels of all the samples formed a substantially clear, transparent film on the face prior to foaming. The gel softened the hair and skin; and the lather produced lubricated the blade throughout the shave, held up the hair, and permitted a clear, close shave with negligible razor burn. It was particularly noted that, when shaving without preliminary washing or rinsing and without rinsing after shaving, the skin felt soft, fresh, and free from significant razor burn.
When the post-foaming gels described above were dispensed under static ambient conditions after about 60 seconds, they were observed to be substantially free from foaming. The flow curves of each of these compositions are set forth in FIG. 1. It is apparent that all foam compositions did have a yield value characteristic of the gels of the invention. In addition, it is apparent from Table I that the foam density of these compositions remained susbtantially constant when the first and last portions dispensed from the package were tested. The foam profile of commercially available aerosol lathers was observed at the same time under similar conditions. To obtain the foam density values, the foam was dispensed into a beaker and maintained in an oven at about 98.6
15 F. for about 15 minutes. The following results were obtained:
Foam density (g./cc.) (first portion of package) 0.078
Foam density (g./cc.) (last portion of package) 0.30 Stiffness (g./cm. (first portion of package) 199 Stiffness (g./cm. (last portion of package) 83 Shear stability (first portion of package) 0.63 Shear stability (last portion of package) 0.92
In Table II below illustrative examples of compositions suitable for use as hair shampoos, hand cleaners, and pharmaceutical preparations are disclosed:
TABLE II Sham- Pharmaceutical Hand Component (percent by weight) poo preparation cleaner 0 Triethanolaminc myristate 6. 0
Myristic acid (97%) Palmitic acid (97%).
Coconut 011 8.0 Palm oil. 4. 0 Olive oil 8. 0 Triethanolamine Sorbitol (70%) Propylene glyco1 3. 5 noel-HA Dye Propylene glycol dipelargonate- Carbopol 934 Potassium hydroxide Ethyl alcohol Benzalkonium chloride Isopar L n-Butana.
n-P entane- Propellant 114 Isopropyl/isostearate 3.0 Deionized water 59.
1. A cleansing or cosmetic composition in the form of a stable, post-forming gel consisting essentially of about 90% by weight water, about 4-25 by weight water-soluble soap, about 0.512% by weight volatile liquid post-foaming agent selected from the group consisting of saturated aliphatic hydrocarbons, halogenated hydrocarbons and mixtures thereof, and about 0.0l-5% by weight of at least one water-soluble gelling agent which forms in said composition, a gel having a yield value sufficiently high to substantially restrain said composition from foaming for at least about 60 seconds, under static ambient conditions.
2. The composition of claim 1 wherein said gel produces a lather having a substantially uniform foam profile.
3. The composition of claim 1 wherein said gel has a yield value of at least about 4.
4 The composition of claim 1 wherein said gel has a vapor pressure at about 90 to 100 F. from about 6 to about 14 p.s.i.g.
5. The composition according to claim 1 wherein said post-foaming agent is substantially insoluble in said gel.
6. The composition of claim 1 wherein said gel is characterized by improved inter-bubble transport as shown in FIG. 3 of the drawing.
7. The composition of claim 1 wherein said gel has a foam profile comprising: a foam density of from about 0.2 to about 0.5 g./cc., a shear stability of from. about 0.8 to about 1.0, and .1 stiffness from about 20 g./cm. to about 80 g./cm.
8. The composition of claim 1 wherein the gelling aid comprises a water-solublederivative of naturally occurring substances selected from the group consisting of cellulose, sucrose, and glucose.
9. The composition according to claim 1 wherein said gel contains a surface active agent selected from the group consisting of anionic and nonionic detergents.
10. The composition of claim 1 wherein said post-foaming agent is selected from the group consisting of an aliphatic hydrocarbon in a concentration from about 1 to about 4 percent by weight, a halogenated hydrocarbon in a concentration from about 2 to about 8 percent by weight, and mixtures thereof.
11. The composition of claim 1 wherein said post-foaming agent is a halogenated hydrocarbon in a concentration of from about 2 to about 8 percent by weight.
12. The composition of claim 1 wherein said gel is a coherent colloidal suspension formed from aqueous solution.
13. The composition of claim 1 wherein said soap comprises a water-soluable salt of a fatty acid.
14. The composition of claim 1 wherein said soap comprises a triethanolamine salt of palrnitic or stearic acid.
15. The composition of claim 1 wherein said gelling aid is at least one water-soluble material selected from the group consisting of (i) copolymers of acrylic acid and polyallyl sucrose; and (ii) reaction products of cellulose or glucose with acids or alkylene oxides.
16. The composition of claim 1 wherein said post-foaming agent is at least one aliphatic hydrocarbon having from 4 to 6 carbon atoms.
17. A stable, post-foaming gel consisting essentially of about 50-80% by weight water; about 4-25% by weight of at least one Water-soluble stearate or palmitate soap; about 0.0l-5% by Weight of at least one water-soluble gelling agent selected from the group consisting of (i) copolymers of acrylic acids and polyallyl sucrose, and (ii) reaction products of cellulose or glucose with acids or alkylene oxides; and about 0.54% by weight of an aliphatic hydrocarbon post-foaming agent having from 4 to 6 carbon atoms; said gel having a coherent colloidal dispersion formed from aqueous solutions and having a yield value of at least about 4 and sufiicient to substantially restrain said gel from foaming under static ambient conditions for at least about 60 seconds.
18. The composition of claim 17 wherein said watersoluble soap is triethanolamine soap.
19. The composition of claim 17 wherein said cellulose derivative is sodium carboxymethyl cellulose.
20. The composition of claim 17 wherein said cellulose derivative is methyl cellulose.
21. The composition of claim 17 wherein said cellulose derivative is hydroxyethyl cellulose or hydroxypropyl cellulose.
22. The composition of claim 17 wherein said postfoaming agent comprises pentane.
23. The composition of claim 17 wherein said postfoaming agent comprises a mixture of pentane and butane.
LEON D. ROSDOL, Primary Examiner W. E. SCHULZ, Assistant Examiner U.S. C1. X.R.