US 3484378 A
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United States Patent Office 3,484,378 Patented Dec. 16, 1969 3,484,378 AEROSOL HEATED SHAVING LATHER DISPENSING PACKAGE Irving Reich, Princeton Junction, and Hans Breuer, Somerville, N.J., assignors to Carter-Wallace, Inc., New York, N.Y., a corporation of Maryland N Drawing. Filed Mar. 17, 1966, Ser. No. 535,043 Int. Cl. C11d 17/00, 9/30; C09k 3/30 US. Cl. 252-90 ABSTRACT OF THE DISCLOSURE A package comprising a valve-actuated, pressurized aerosol shaving lather product dispensing container for passing a lather product being dispensed from said container in physical heat-transfer relation with means for heating said product, said container containing an aerosol lather formulation for use in roducing a heated shaving lather consisting essentially of a liquid mixture of an aqueous soap solution and a volatile halogenated alkane propelent, said soap solution containing 618 percent by weight of triethanolamine stearate, 1-3 percent by weight of triethanolamine cocoanut oil soap and excess stearic acid in an amount from 1 to 3 percent by weight.
This invention relates to an aerosol package for dispensing heated aerosol shaving lathers of satisfactory quality, stability and performance.
Aerosol shaving lathers have been in widespread use since 1949, the basic formulations being first described in US. Patent No. 2,655,480. Recently, considerable interest has developed in the possibility of heating these aerosol lathers before use. A heated lather is superior to a cold lather in comfort of use and in ability to swell and soften the beard hairs. Several patents have issued describing methods of applying heat to a portion of the lather either while it is emerging from the container or just before it emerges (US. Patent Nos. 2,873,351; 3,098,925; 3,095,122 and 3,171,572).
Typical formulations for producing aerosol shaving lathers are described in column 9 of the hereinbe-fore mentioned US. Patent No. 2,655,480. A basic formula which is still widely used with limited modifications is a composition consisting of a soap solution containing 8% triethanolamine stearate plus 2% triethanolamine cocoanut-oil soap, pressurized with a mixture of Freon 12 (dichlorodifiuoromethane) and Freon 114 (1,2 dichlor- 1,1,2,2 tetrafluorethane).
Triethanolamine soaps of this type were unusual in shaving lathers when Patent No. 2,655,480 issued, but they proved especially suitable for aerosol lathers because they provided lather which was milder, finerbubbled, and more stable than the conventional potassium-sodium soap. The triethanolamine stearate serves as the main lather-forming soap, with the triethanolamine cocoanut-oil soap serving the function of maintaining the solution fluid in the can and minimizing the chances of this solution thickening and hence emerging as a sputtery, uneven lather.
Various modifications of this basic formula are in general use in the aerosol shaving-cream industry. The soap solution usually contains a solube humectant, such as glycerin or propylene glycol. The levels of the soaps may be somewhat higher or lower, leading to some variations in the texture and viscosity of the lather. Sometimes lanolin or other oily substances are included for their alleged skin-conditioning action. Non-ionic wetting agents, such as the polyoxyethylene esters of fatty acids may be included for their alleged ability to improve beard wetting and because they cause the lather to feel heavier and richer. Menthol and various medicating agents are often incorporated.
4 Claims It has been found that the conventional aerosol lather formulas, although perfectly satisfactory for cold lather, are unsuitable for heated aerosol lather. The heated lather is unduly soft and wispy. It appears coarse and lacks the heaviness and body needed for proper shaving performance. For reasons which are not fully understood this deficiency is much more noticeable in heated aerosol lathers than in warm lathers generated by the old-fashioned brush method.
This defect is augmented when the heated lather is forced through a narrow space under pressure. All of the heating methods described in the above referred to patents related to heated lathers involve passage of heated lather through narrowly-constricted spaces, such as a tube or the space between two closely-opposed plates or a maze of steel Wool plus a valve opening, The shearing action to which the heated lather is subjected increases its tendency to become coarse, soft and Weak.
Objects and advantages of the invention will be Set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the steps, methods, compositions, combinations and improvements pointed out in the appended claims.
The invention consists in the novel steps, methods, compositions, combinations and improvements herein shown and described.
An object of this invention is to provide an improved aerosol heated shaving lather dispensing package. M re particularly, an object of this invention is to provide an aerosol heated shaving lather dispensing package package wherein the heated lather dispensed therefrom is of satisfactory quality, stability and performance.
It has been found that the objects of this invention may be realized by employing as the shaving lather formulation in an aerosol heated shaving lather dispensing package, an aqueous solution of triethanolamine stearate superfatted with an excess of stearic acid; such soap solution forming a heated lather which is rich, heavy, fine-bubbled, and generally satisfactory. In general, the concentration of triethanolamine stearate may range from about 6% to about 20% and the concentration of excess stearic acid from about 1% to about 4%. However, for the lower portion of the range of triethanolamine stearate concentration, it is necessary to employ a rather large concentration of stearic acid, while at the higher levels of triethanolamine stearate, as little as 1% of excess stearic acid is adequate.
In testing aerosol lathers, the products were passed through the heater described in claim 18 of US. Patent 3,171,572. The cup was filled with water at approximately 138 F. and the lather emerged at approximately 7 cc. per second, at a temperature of -115 F. The lather quality was graded on a scale running A+ to D. A grade of A+ represents a rich, stable, fine-bubbled lather fully equal in consistency and texture to a usual cold aerosol lather, such as the one formed according to the formula in claim 21 of US. Patent 2,655 ,480. A grade of A is slightly poorer but still satisfactory, while A- is poorer still, indicating some obvious weakness and coarseness. Grades of B+ are marginal, while lower grades are considered poor and not desirable for shaving use, although the grading system is continued down as far as D in order to develop the full pattern of lather performance as a function of formula.
In addition to the quality of the heated lather, ratings were made of fluidity of the pressurized soap solution. All solutions were pressurized with a combination of Freons 12 and 114 to yield a lather of density 0.085 grams/ cc. and having a pressure of 50 p.s.i.g. in the container. Fluidity was noted after pressurizing in a transparent glass bottle, shaking as usual, allowing the container to stand for several days, and then observing whether the liquid in the container was gelled and immobile (gelled), or moved sluggishly on shaking (viscous), or flowed readily (fluid).
Gelling of the fluid in the container is highly objectionable, since it makes it impossible for the user to distribute the emulsified propellant evenly throughout the soap solution by shaking. It is also likely to result in the lather emerging unevenly, with sputtering. A viscous liquid is acceptable but is less desirable than a fluid liquid, since it requires more shaking for proper distribution of propellant and since it might gel under unusual conditions of storage. The following table shows the qualities of heated lathers and the fluidities of pressurized soap solutions made with various proportions of triethanolamine stearate and excess stearic acid. All soap solutions referred to in this disclosure contained glycerin, a standard humectant, except where otherwise indicated.
TABLE I Percent Excess Stcaric Acid Triethanolamine Stearate 0 1 2 3 4 Percent: 6
Formulas with 2% and 3% excess stearic acid give fair to good results, but the solutions are usually viscous. With 4% excess stearic acid the solutions gel and hence are unsuitable. With only 1% stearic acid, results are good provided the concentration of triethanolamine stearate is high, in the neighborhood of 16%. At no level of triethanolamine stearate is a satisfactory lather obtained in the absence of excess stearic acid.
In general, solutions of triethanolamine stearate Without cocoanut soap are superior to solutions containing cocoanut soap in stability of heated lather. If a limited amount of cocoanut-oil soap is included, these solutions become more fluid, but at the same time the qualities of the heated lathers become poorer. However, the quality of heated lather can be restored by going to higher levels of stearic acid. In general, if 1% cocoanut-oil soap is present, the excess stearic acid should be at least 2%, while if 2% cocoanut-oil soap is present, 3% or more excess stearic acid is desirable.
These combinations of triethanolamine stearate, triethanolamine cocoanut-oil soap, and excess stearic acid in correct proportions will form excellent soap solutions which are quite fluid and yet yield rich, stable heated lathers. The following table shows data for compositions containing 1% triethanolamine cocoanut-oil soap.
TABLE II Percent Excess stearic Acid (All Solutions Contain 1% TEA Coco) Triethanolarnine (viscous). n
TABLE III Percent Excess stearic Acid (All Solutions Contain 2% TEA Coco) Trictliaiiolaiuirie Stearate 0 1 2 3 4 Percent 7 D B A (fluid) (fluid). (fluid). 8 C- A+ A+ (fluid) (fluid) (fluid) (fluid). 10 O B+ A+ (fluid). (fluid) (fluid). 13 B- A A A (fluid) (fluid) (semi-vis- (fluid) cous). 16 B A- (fluid). (fluid). (gelled We have found that the quality of the heated lather can be defined in terms of the functions Q=T+1OS4C Where T is the percentage of triethanolamine stearate, S is the percentage of excess free stearic acid, and C is the percentage of triethanolamine coco soap. Compositions with Q- less than 20 are unsatisfactory. Compositions with Q over 20 give satisfactory heated lather, with the best results obtainable when Q is over 24.
As noted earlier, some compositions are unsuitable because the pressurized soap solution gels. Gelling is promoted by unduly high concentrations of triethanolamine stearate and especially by unduly high concentrations of excess free stearic acid, while it is reduced by triethanolamine coco soap. We have set up the function with T, S, and C defined as above. Gelling is likely to occur when G is over 20, and it is virtually certain to occur when G is over 25.
It follows that acceptable formulas include those with Q over 20 and G under 25, while preferred formulas are those with Q over 24 and G under 20.
Since a given formula can be calculated in various ways to show various apparent levels of the two soaps and excess fatty acids, We have adopted the following conventions for expressing all formulas in this disclosure:
(1) All of the cocoanut fatty acids are assumed united with the triethanolamine as triethanolamine coco soap.
(2) The remaining triethanolamine is assumed united with stearic acid as triethanolamine stearate.
(3) The remainder of the stearic acid is assumed present as free excess stearic acid.
These conventions have been used in specifying all listed formulas and in calculating the functions Q and G.
Preferred ranges of individual components are triethanolamine stearate 6l8%, excess stearic acid l4%, triethanolamine coco soap 0-4%. Examples of typical formulas are given below, showing how their characteristics correspond with the criteria noted above. The formulations which follow may contain conventional shaving lather additives, such, for example, minor amounts of glycerin (5%) to aid in preventing the lather from drying out, perfume (3%) etc,
PREFERRED FORMULAS Heated TEA Excess TEA Lather Stearate Stearie Coco Q Grade G Fluidity us 1 20 A 19 Fluid. 14. 2 1 30. 5 A 19. 5 Do. 11 3 1 37 A 19 D0. 8 3 2 130 A+ 15 Do. 10 4 2 42 11+ 20 Do. 8 4 2 40 A 18 D0. 10 3 3 28 A+ 19 Do.
ACCEPTABLE FO RMULAS 12 1 0 22 A- Fluid. 12 3 0 42 A 21 Viscous 14. 5 4 1 5o. 5 A+ 25. 5 o
10 2 2 22 13+ 14 Fluid.
UNSA'IISFACTO RY FORMULAS 0 0 8 C 8 Fluid. 1% 0 0 15 B 15 Do. 15 4 0 55 A-i- 27 Gelled. 14. 5 O 1 10. 5 B 13. 5 Fluid.
8 0 2 0 O- 7 D0. 16 0 2 8 B 14 Do. 7 2 2 19 B 11 D0. 16 4 2 48 A+ 26 Gelled.
Since incorporation of propylene glycol or water soluble non-ionic wetting agents in the soap solution makes the cold lather considerably richer and more viscous, it mlght be expected that this would result in improved quality for the heated lather. Surprisingly, we have found ust the opposite. Triethanolamine soap solutions contarnlng appreciable levels of non-ionic wetting agents or propylene glycol and forming heavy, rich lathers at room temperature break down to almost watery consistency when heated and spread on the face.
Addition of excess stearic acid has only a moderate tendency to increase the stability and viscosity of cold lather. It is surprising that it is highly effective 111 increasing the stability and viscosity of heated lather, whereas such conventional additives as water-soluble nonionic surfactants, which greatly increase the viscosity of cold lather, are entirely useless in heated lather. We have found that the addition of excess stearic acid results in soap solutions which become very viscous when heated, whereas water-soluble non-ionic agents cause the soap solution to become thinner upon heating. It appears, therefore, although this invention is not limited to any theory of action, that this tendency of excess stearic acid to stabilize hot lathers depends on its ability to thicken heated soap solutions. The fact remains that excess stearic acid at proper levels does modify alkylolamine soap solutions in such a way that they form rich, stable heated lathers.
It is interesting to note that the fifth formula in the foregoing unsatisfactory group is that described in claim 21 of the original aerosol lather Patent No. 2,655,480. This is the preferred formula in the patent and it does, in fact, give an excellent cold aerosol lather, with fine body and stability, but on heating the lather becomes weak, thin, and unsatisfactory for shaving purposes.
The container for the aerosol formulation used in accordance with this invention may be any of the known value-actuated, pressurized, aerosol-type foam or lather product dispensing pressure-tight containers provided with, or in association with, heating means for heating lather product dispensed from the container. The aforementioned heating means may be a heating device which heats the lather as, or just prior to or after, it emerges from the outlet of the container. A preferred container is that of the type disclosed in U.S. Patent 3,171,572. Examples of other containers which may be used for producing the package of this invention are those disclosed in U.S. Patents 2,873,351; 3,098,925; 3,175,733.
The propellant of the aerosol formulations used in accordance with this invention may be any of the conventionally used halogenated alkanes having not more than two carbon atoms and containing at least one fluorine atom, the atomic weight of each halogen atom not exceeding 36, disclosed in column 5, line 14 to column 7, line 3 of U.S. Patent 2,655,480. As pointed out in the column 3, line 73 to column 6, line 20 of the above referred to patent, the most desirable propellants for lather forming compositions are the substantially water insoluble chlorine and fluorine substituted hydrocarbons of the proper vapor pressure range. Examples of these propellants are:
1,2-dichlor-l,1,2,2-tetrafluorethane (CClF CClF Trichlortrifluorethane (C CI F Dichlordifluormethane (CCl F Monochlordifluormethane (CHCIF Monofiuortrichlormethane (CFCl l,l-difluorethane (CH CHF l-monochlor- 1 1 -difluorethane (CClF- CH As to these compounds, absence of tingling sensation combined with production of the best shaving lather consistency is achieved by using those propellants in which all of the hydrogen atoms are replaced by chlorine and fluorine and in which the number of fluorine atoms equals or exceeds the number of chlorine atoms, as is true, for example, of dichlordifluormethane, l,2-dichlor-1,l,2,2- tetrafluorethane and trichlortrifluorethane.
Mixtures of different propellant compounds are useful for providing the particular vapor pressure desired, and propellants comprising mixtures of dichlordifluormethane and 1,Z-dichlor-l,1,2,2-tetrafluorethane, of monofluortrichlormethane and dichlordifluormethane and of trichlortrifluorethane and dichlordifluormethane are satisfactory for this purpose. For example, dichlordifluormethane, which has a vapor pressure of about pounds per square inch gauge and 1,2-dichloro-1,1,2,2- tetrafluormethane, with a vapor pressure of about 13 pounds per square inch gauge at 70 F., may be mixed in various proportions to form a propellant having an intermediate vapor pressure which is well suited for use in relatively inexpensive containers.
As indicated hereinbefore, an important element of the aerosol formulation used in accordance with this invention is triethanolamine stearate. As is well known, the product sold commercially as stearic acid is actually a mixture consisting primarily of stearic and palrnitic acid. The term stearate as used herein is to designate the triethanolamine soap of commercial stearic acid; although the triethanolamine soap of the chemically pure above mentioned acids would be equivalent for the purposes of this invention.
The invention in its broader aspects is not limited to the specific steps, methods, compositions, combinations and improvements described, but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.
What is claimed is:
1. A package comprising a valve-actuated, pressurized aerosol shaving lather product dispensing container for passing a lather product being dispensed from said container in physical heat-transfer relation with means for heating said product, said container containing an aerosol lather formulation for use in producing a heated shaving lather consisting essentially of a liquid mixture of an aqueous soap solution and a volatile halogenated alkane propellant having not more than two carbon atoms and containing at least one fluorine atom, the atomic weight of each halogen atom not exceeding 36, said soap solution containing 6-18% by weight of triethanolamine stearate and excess stearic acid in an amount from 1 to 3% by weight.
2. A package comprising a valve-actuated, pressurized aerosol shaving lather product dispensing container for passing a lather product being dispensed from said container in physical heat-transfer relation with means for heating said product, said container containing an aerosol lather formulation for use in producing a heated shaving lather consisting essentially of a liquid mixture of an aqueous soap solution and a volatile halogenated alkane propellant having not more than two carbon atoms and containing at least one fluorine atom, the atomic weight of each halogen atom not exceeding 36, said soap solution containing 845% by weight of triethanolamine stearate, 13% by weight of triethanolamine cocoanut oil soap and excess stearic acid in an amount from 2 to 4% by weight.
3. A package comprising a valve-actuated, pressurized aerosol shaving lather product dispensing container for passing a lather product being dispensed from said container in physical heat-transfer relation with means for heating said product, said container containing an aerosol lather formulation for use in producing a heated shaving lather consisting essentially of a liquid mixture of an aqueous soap solution and a volatile halogenated alkane propellant having not more than two carbon atoms and containing at least one fluorine atom, the atomic weight of each halogen atom not exceeding 36, said soap solution containing triethanolamine stearate in an amount of 713% by weight, excess stearic acid in an amount of 34% by weight and triethanolamine cocoanut oil soap in an amount of 2% by weight.
4. A package comprising a valve-actuated, pressurized aerosol shaving lather product dispensing container for passing a lather product being dispensed from said container in physical heat-transfer relation with means for heating said product, said container containing an aerosol lather formulation for use in producing a heated shaving lather consisting essentially of a liquid mixture of an aqueous soap solution and a volatile halogenated alkane propellant having not more than two carbon atoms and containing at least one fluorine atom, the atomic weight of each halogen atom not exceeding 36, said soap solution containing triethanolamine stearate in an amount of 14.5% excess stearic acid in an amount of 2% and triethanolamine cocoanut oil soap in an amount of 1%, and wherein the propellant is a combination of dichlordifluormethane and 1,Z-dichlor-l,1,2,2-tetrafluorethane.
References Cited UNITED STATES PATENTS 8/1961 Bluard 252 8/1967 Marcoux 167-82 US. Cl. X.R. 252-117, 118, 305