US2316194A

US2316194A - Detergent composition

Info

Publication number: US2316194A
Application number: US236090A
Authority: US
Inventors: Gilbert C Toone; Lawrence H Flett
Original assignee: Allied Chemical and Dye Corp
Current assignee: Allied Corp
Priority date: 1938-10-20
Filing date: 1938-10-20
Publication date: 1943-04-13
Anticipated expiration: 1960-04-13

Description

Patented Apr. 13, 1943 DETERGENT COMPOSITION Gilbert 0. Toone and Lawrence H. Flett,

' N. Y., assignors to Allied Chemical & poration, a corporation of New York,

Hamburg, Dye Cor- No Drawing. Application October 20, 1938,

Serial No. 236,090

11 Claims.

The present invention relates to detergent compositions containing'as an essential detergent ingredient one or more water-soluble salts of alkyl esters described more fully below. 'The invention more particularly relates to detergent compositions comprising one or more of these alkyl ester salts which compositions in the dry form or in the form of solutions are especially adapted for use as shampoos.

The alkyl ester salts which constitute the essential detergent ingredient of the detergent compositions of the present invention are alkali metal salts (which term is meant to also include the ammonium salts) of sulfo aliphatic mono carboxylic alkyl esters (sulfo-fatty esters) containing 2 to 4 carbon atoms in the acyl radicals and 12 to 18 carbon atoms in the alkyl radicals thereof. (Hereinafter, these esters are sometimes referred to as alkyl esters of sulfo aliphatic carboxylic acids, and sometimes simplyas alkyl ester salts.) These alkyl ester salts are derivable from sulfoacetic acid, sulfopropionic acid, and

sulfobutyric acid, and any of a wide variety of aliphatic alcohols (e. g., straight and branched chain aliphatic alcohols) containing 12 to 18 carbon atoms. Inasmuch as alcohols of this class derived from naturally occurring fatty acids may be used in the preparation of the alkyl ester salts, the alkyl ester salts, when manufactured from said alcohols, are ordinarily mixtures of compounds rather than single compounds; An outstanding example of this class of alkyl ester salts is the mixture of sulfo acetates, designated lauryl sulfo acetate and prepared from commercial lauryl alcohol which is derived from the mixed fatty acid glycerides of cocoanut oil.

Although these alkyl ester salts have good detergent power, and are neutral in character, attempts to employ them alone or in an unmodifled form for cleaning applications in which their lathering properties are especially desirable, and particularly for use as shampoos, have not been entirely successful. This is due to a number of factors related to the requirements of an acceptable shampoo, and the properties of the alkyl ester salts. In order for a shampoo to'be commercially acceptable, it should have good la'thering power. Further, it should be an effective cleansing agent for the hair and scalp, but it should possess little, if any, of the objectionable property of removing too much oil from the hair and scalp and leaving these in an excessively dry state. Further, the aqueous solutions of the shampoo preferably should be stable over a wide range of temperatures, and have a of viscosity.

The above alkyl ester salts in themselves do not have all these required properties. Thusfor aqueous solutions of these alkyl ester salts alone to have strong lathering powers, when used in fair degree the usual small amounts, the alkyl ester salts must be present in substantial concentration. When using a concentrated aqueous solution of one of these alkyl ester salts, it has been found that the defatting power of the solution is such that when the solution is used in sufiicient amounts to produce a satisfactory lather, the 'defatting power of the solution is, in general, too drastic, since it not only is eflective in cleansing the hair and scalp, but also removes an excessive quantity of the natural oils from the hair and skin. In the case of barbers and beauty parlor operators who, as a rule, manipulate shampoos with bare hands, this would be especially objectionable because the removal of the natural oils from their hands by the continual use of the solutions would lead to cracking of the skin. Solutions of this type obviously are objectionable if used as shampoos for dry hair and scalp.

These concentrated solutions sometimes have a further disadvantage resulting from the fact that the solubilities of these alkyl ester salts in water vary greatly with changes in temperature. Thus, a concentrated aqueous solution of an alkyl 'ester in the form of a neutral salt; e. g., a sodium salt, may be prepared so as to-be perfectly clear at the temperature of preparation. However, on lowering the temperature of such a solution, it becomes supersaturated, and for a time persists as a clear solution and then precipitates to yield a cloudy solution or unsightly mixture. Aqueous mixtures which are cloudy 'or' which contain unsightly precipitates are not acceptable to consumers.

It is an object of this invention to prepare detergent compositions which contain one or more alkali metal salts of alkyl esters of sulfo aliphatic carboxylic acids containing 2 to 4 carbon atoms in the acyl radicals and 12 to 18 carbon atoms in the alkyl radicals thereof, which compositions are superior in their characteristics to compositions containing one or more of these alkyl ester salts only, and are particularly well adapted for use as shampoos and for related purposes.

A further object of the invention is to provide compositions comprising aqueous solutions containing one or more of the above-described alkyl ester salts, which compositions lather freely, and may be produced economically.

A further object of the invention is to provide compositions comprising concentrated aqueous solutions containing one or more of the abovedescribed alkyl ester salts, which solutions lather freely, and have detergent power such that they may be used as shampoos without injury to the hair, scalp, or skin.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

It has been discovered in accordance with the present invention that detergent compositions which contain as the essential detergent; ingredient one or more alkali metal salts of alkyl esters of sulfo 1, aliphatic carboxylic acids which contain 2.to 4 carbon atoms in the acyl radicals and 12 to 18 carbon atoms in the alkyl radicals thereof and which are substantially free from the abovediscussed disadvantages of these alkyl ester salts when used alone can be prepared by associating with one or a mixture of these alkyl ester salts a compound of the class described more fully blow. For simplicity in terminology, a compound of this class, whether used singly or in admixture with one or more other compounds of the class, is referred to herein as a stabilizing agent. The compositions may be in the form of dry mixtures which are very readily soluble in water, and therefore can be applied directly to the hair and scalp. They may also be in the form of aqueous solutions which are particularly adapted for use as shampoos for the hair and for the washing of fine fabrics, upholstery and rugs.

Thus it has been found that by associating a stabilizing agent with an alkyl ester salt of the above class, such as sodium lauryl sulfoacetate,

compositions are obtained which can be employed for the preparation of concentrated aqueous solutions which have lathering powers considerably in excess of the lathering powers of solutions containing the same amount of alkyl ester salt, but omitting the stabilizing agent. In fact, an aqueous solution which contains a mixture of an alkyl ester salt and a stabilizing agent in a certain total concentration of alkyl ester salt and stabilizing agent can be prepared which possesses substantially the same lathering power as a solution having a concentration of alkyl ester salt alone equal to this total concentration. The compositions of the present invention in the form of aqueous solutions have the important advantage over solutions of alkyl ester salts alone in that, while they have substantially equal lathering powers and satisfactory cleansing properties, they have weaker defatting properties and therefor, when used for shampooing the hair, do not remove an excessive amount of oil from the hair, scalp, or skin.

Asbefore pointed out, it is important that commercial shampoos in the form of solutions should remain clear at relatively low temperatures; that is, they should have relatively low turbidity points. The surprising discovery has been made that by adding the stabilizing agents to aqueous solutions of one of the above-described alkyl ester salts of sutiicient concentration to be turbid to solid at room temperatures, solutions are formed which not only do not have higher turbidity points than the aqueous solutions of the alkyl ester salts, but in such cases the turbidity points are lower. Because of this property of the stabilizing agents, it has been found that aqueous solutions can be prepared having high total content of alkyl ester salt and stabilizing agent so that the solutions have excellent lathering properties and yet, despite the highly concen- I trated nature of the solutions, their turbidity points are such that they may be handled and stored at ordinary household temperatures without developing turbidity.

The stabilizing agents used in accordance with the present invention are composed of one or more compounds which are alkali metal salts (which term is meant to include also the ammonium salts) of mono alkyl sulfates and of sulfo aliphatic monocarboxylic alkyl esters in which the alkyl radicals contain 5 to 11 carbon atoms, but contain no straight carbon chain of more than 9 carbon atoms, and the organic acyl radicals contain 2 to 4 carbon atoms. Th..s the stabilizing agents are composed of one or more water-soluble monoalkyl esters of sulfuric acid, sulfoacetic acid, sulfopropionic acid, or sulfobutyric acid, wherein the alkyl groups contain 5 to 11 carbon atoms, but not more than 9 carbon atoms in a straight chain. The compounds are preferably used in the form of their neutral salts, such as their alkali metal (including ammonium) salts, particularly the sodium salts. It has been found that of the compounds of this class those which contain 6 to 8 carbon atoms in the alkyl groups thereof, are generally to be preferred for use in the present compositions. larly it has been found that monoalkyl esters of the above class in which the alkyl groups are octyl groups, especially 2-ethyl-hex'yl groups, are particularly effective for use in the stabilizing agents. Specific examples of compounds which may be used singly or in the form of mixtures as stabilizing agents in the compositions are the following: neutral sodium, potassium, ammonium salts of normal hexyl sulfoacetate, secondary hexyl sulfoacetate, mono-normal hexyl sulfate, mono-Z-ethyl-butyl sulfate, heptyl sulfoacetates, normal octyl sulfoacetate, secondary octyl sulfoacetate, Z-ethyl-hexyl sulfoacetate, mono-2- ethyl-hexyl sulfate, 2'-ethyl-hexyl sulfobutyrate, mono-nonyl sulfate, and an alkyl sulfoacetate in which the alkyl group contains 11 carbon atoms in a branched-chain in which not more than 9 carbon atoms are in a straight chain.

The stabilizing agents alone are at best weak lathering agents and in some cases display no lathering properties at all. Nevertheless, these agents have surprisingly been found to possess the ability of increasing the lathering properties of the long-chain alkyl ester salts described above. At the same time, since the stabilizing agents have substantially no defatting properties, the aqueous solutions of mixtures of the alkyl ester salts and stabilizing agents in general are' less drastic in their defatting action than aqueous solutions of the alkyl ester salts alone having the same lathering properties. The reason why the stabilizing agents do not raise the turbidity points of aqueous solutions of the long-chain alkyl ester salts, but, instead act to lower the turbidity points of such solutions, is not clearly understood. Whatever the theoretical explanation of the action of the stabilizing agents may be, the compositions of the present invention containing the stabilizing agents in association with the long-chain alkyl ester salts so combine the excellent cleansing and lathering powers of the latter compounds with the lather-inducing and stabilizing powers of the stabilizing agents that the concentrated aqueous solutions of the compositions are characterized by the controlled washing and 'high lathering qualities, and stability and clarity which are demanded of the highest quality shampoos; yet they do not have the i excessive defatting powers that are an objectionable feature of the ordinary aqueous solutions of the long-chain alkyl esters.

As previously indicated, the long-chain alkyl ester salts used in the compositions of the present invention may be single compounds or mixtures of compounds, as, for example, the mixture of alkyl sulfoacetates which contains a preponderating amount of monolauryl, monomyristyl, and monocetyl sulfoacetates, and which can be made More particufrom the commercial lauryl alcohol obtained as a mixture of alcohols resulting from the hydrogenation 'of the lower alkyl esters of the fatty acids of saponifled cocoanut oil. In referring to lauryl sulfoacetate or other alkyl sulfoacetate herein and in the'claims, it will be understood that the commercial product as well as the substantially pure compound is'intended.

While any of the above-described long-chain alkyl ester salts may be used in the present compositions, it has been found that particularly valuable compositions are obtained with the use of commercial lauryl sulfoacetate, preferably in the form of the sodium salt. Compositions containing this compound and a stabilizing agent, especially a stabilizing agent containing a compound having a 2-ethyl-hexyl group, have been found to be particularly valuable for use as shampoos.

The compositions of thepresent invention are conveniently prepared in a simple manner by mixing the long-chain alkyl ester salt and the stabilizing agent in the dry state in proportions such that the resulting mixture may be dissolved in water to produce an aqueous solution having the desired properties of detergency. lathering. and solubility; the components and proportions to be employed in any particular case being dependent upon the properties which it is desired to have the resulting composition possess. Be-

cause of the variable properties of the compounds composing the stabilizing agents, in many cases it is preferred to employ a stabilizing agent containing two or more compounds rather than one consisting of a single compound.

In connection with the proportioning of the components of the compositions, it should also be noted that while the above-described longchain alkyl ester salts as a class possess the properties described herein, individual members of the class differ one from another in the degree in which they possess one or more of these properties. Hence, no general rule as to the optimum specific proportions is applicable to all mixtures. However, it can be stated that the amount of stabilizing agent to produce the beneficial results of the present invention should not be less than three-fourths to one part by weight-for each part by weight of the alkyl ester salt or mixture of alkyl ester salts and as a general rule the compositions preferably should not contain more than ten parts byweight of stabilizing agent for each part by weight of the alkyl ester salt or mixture of alkyl ester salts. compositions of the invention contain from about one and one-half to about five parts, or better, from about one and one-half to about four parts. by weight of the stabilizing agent for each part by weight of the alkyl ester salt.

In preparing the compositions of the invention in the form of aqueous solutions, in order for the solutions to possess adequate cleansing and lathering powers, it is necessary that the combined content of long-clrain alkyl ester salt and stabilizing agent should constitute at least five per" cent, and preferably at least ten per cent, by weight of the solutions. Further, to avoid high turbidity points, the solutions preferably should not have more than fifty per cent combined content of alkyl ester salt and stabilizing agent. In fact, for most purposes, solutions having such a combined content of not more than 35 per cent are preferable. The preferred solutions, therefore, are those which have a combined The preferred alkyl ester salt and stabilizing agent content of from 10 to 35 per cent.

When making up these solutions, it will be understood that the proportioning of theingredients will be dependent upon the concentrations of the solutions as well as upon the specific longchain alkyl ester salts and stabilizing agents used. The preferred solutions of the present invention are those which remain clear above 10 C. and, after being precipitated, clear up below 20 C. By applying the above principles with respect to the proportioning and selection of ingredients, concentrated solutions can be prepared having turbidity points of this nature.

A property of aqueous solutions of the longchain alkyl ester salts intended for use as shamp005 and for related purposes which is of some importance is the viscosity of the solutions. While this property is not an indication of the basic functional worth of the solutions, it does have an effect on their merchantability. It has been found that the viscosity of aqueous solutions of the alkyl ester salts may be controlled by the amount and character of stabilizing agent incorporated therein. Thus it has been found that as the amount of stabilizing agent is increased in proportion to the amount of alkyl ester salt, the viscosity of the solution decreases to a minimum and then increases rapidly.

In order to obtain a solution having the detergent and lathering properties in the degree desired in a particular instance, which properties are dependent in some measure upon the specific properties of the alkyl ester salt and the stabilizing agent, it may not be feasible to employ an amount of stabilizing agent such as to impart optimum viscosity characteristics to the solution. In many cases, however, it is possible to prepare solutions having excellent viscosity characteristics, and the desired detergent and lathering qualities, by taking into account the above-mentioned property of the stabilizing agents when making up the compositions. As a feature of the invention, it has been found that the viscosity of highly concentrated solutions, say from 16 per cent to 50 per cent strength, can be increased by using in the compositions highly solublestabilizing agents with or without the further addition of a compatible highly soluble salt such as ammonium sulfate, sodium citrate, sodium tartrate,

sodium malate, etc. The viscosity of lower conhighly concentrated solutions, say from 15 per cent strength, can be increased by the addition of gums such as karaya, locust bean gum, gum tragacanth, etc. compositions not only increases the viscosity of their aqueous solutions, but also increases the stability of the foam or lather which they produce on use. The aforementioned highly soluble salts also act as buffers, and they may be added to solutions for this purpose, if desired.

The following examples are given to illustrate the invention. The parts in the examples are by weight:

Examples 1 to 3 illustrate the properties of the stabilizing agents of increasing the lathering properties (used herein to denote, generically,

foaming, frothing, and lathering properties) of the aqueous solutions of the long-chain alkyl ester salts. To demonstrate the lathring properties of the aqueous solutions, an apparatus was used consisting of a 500 cc. cylindrical graduate and a plunger consisting of a No. 9 rubber stopper or cork (having a top diameter of about 1% inches, a bottom diameter of about i inches, and a The addition of a gum to the v of the graduate at a rate of about two strokes per second for thirty seconds. The stopper or cork was of such a size that it slipped easily inside the cylinder. The solutions were tested at about the same temperature and the time intervals were measured by a stop watch. After the lather was generated, the volume of liquidwhich had separated at the bottom of the graduate was measured at half minute intervals for three minutes, and at one minute intervals for the next two minutes. The smaller the amount of liquid separated, the greater was the lathering power of the tested solutions.

EXAMPLE 1.Three aqueous solutions were pre-- pared as follows: f

Solution #1.One part by weight of commercial sodium lauryl sulfoacetate (prepared from commercial lauryl alcohol obtained by the reduction of the fatty acids derived from cocoanut oil) was dissolved in 100 parts water.

Solution #2.One part by weight of commer cial sodium 2-ethyl-hexyl sulfoacetate was dissolved in 100 parts water.

Solution #3.One part by weight of a mixture of equal weights of sodium lauryl sulfoacetate and sodium Z-ethyl-hexyl sulfoacetate was dissolved in 100 parts water.

Each of the solutions was tested for lathering qualities in the manner described above. The results obtained are recorded in the following table, in which the average experimental error is about two units at the five minute interval:

It will be seen from the results obtained with Solutions #1 and #3 that by replacing one-half of the sodium lauryl sulfoacetate in Solution #1 with sodium Z-ethyl-hexyl sulfoacetate, a solution is obtained (Solution #3) having substantially the same lathering properties. This is surprising since the results obtained with Solution #2 show that sodium 2-ethyl-hexy1 sulfoacetate has weak lathering properties. This example, therefore, illustrates an important advantage characterizing the present compositions; i. e., aqueous solutions of the compositions of the present invention having a certain total concentration of long-chain alkyl ester salt and stabilizing agent having lathering properties comparable to the lathering properties of solutions having a concentration of the same alkyl ester salt alone equal to this total concentration.

EXAMPLE 2.The lathering qualities of aqueous solutions at different concentrations of sodium lauryl sulfoacetate, of sodium 2-ethyl-hexyl sulfoacetate, and of a mixture of these were determined in the foregoing manner. The following table summarizes the results obtained:

cgmtggsifioln (if es so ut on n Amount liquid in 00. separated from zgg g g ggi lather obtained from treatment of 50 (x3. mug agent pet of solution in desi nated time intervals 100 0c- Sodium Sodium lauryl 1 2 3 14 1 1% 2 2% 3 4 5 sulroe y min. min. min. min min. min. min. min. acetate acetate 0 1 1 2 5 6 12 18 (i 1 3 5 7 10 21 0 1 3 5 8 11 26 3 7 11 15 19 22 26 29 6 14 19 27 29 33 35 0. 10 41 44 44 44 45 46 46 0. 19 37 42 44 45 45 45 45 46 0. 28 33 39 41 42 43 44 '15 45 0. 40 12 21 27 31 34 37 40 41 0. 5 12 18 23 28 32 37 40 0.10 0 0 1 2 4 6 10 15 0.19 0 0 l 3 5 6 12 18 O. 28 0 0 1 3 5 7 2 19 O. 40 0 0 2 4 6 8 15 21 These results show clearly that the lathering properties of alkyl ester salts are improved by mixing the said detergents with stabilizing agents which per se have little, if any, lathering properties. In some instances the lathering power of the mixtures has been found to be even greater than that of a detergent solution of equal concentration. (For example, compare 3, 4 and 5 minute readings of horizontal row 1 with those of horizontal rows 11 and 12 in the above table.)

EXAMPLE 3.-Comparisons were made of the lathering qualities of aqueous solutions of sodium lauryl sulfoacet-ate and of mixtures of this detergent with each of the following stabilizing agents (the octyl group of these agents is the Z-ethyl-hexyl group) (a) Sodium octyl sulfate (1)) Sodium octyl sulfoacetate The results of the several tests are summarized in the following tables:

Table 1 LIQUID SEPARATION FROM LATHER GENERATED WITH A SOLUTION CONTAINING 0.5 GRAM SODIUM LAURYL SULFOACETATE PER CC. OF SOLUTION Elapsed time in minutes kiln/22143 4 s No. of cc. of liquid separation 0 1 l 2 5 6 12 18 Table 2 LIQUID SEPARATION FROIVI LATHER GENERAIED W'ITH SOLUTIONS CONTAINING 0.2 GRAM SO'DIUIVI LAURYL SULFOACETATE AND 0.3 GRAM OF STA- BILIZING AGENT PER 100 CC. OF SOLUTION Elapsed time in minutes Solutions containing:

No stabilizing agent 1 5 s 11 14 1s 24 29 Sodium octyl sulfate 0 1 3 4 6 10 16 23 Sodium octyl sulfoacetate 0 0 l 3 4 7 l3 l8 Table 3 Elapsed time in minutes Solutions containing:

No stabilizing agent 6 14 19 23 27 29 33 35 Sodium octyl sullate 1 3 5 7 ll 15 23 28 Sodium octyl sulfoacetate 0 l 2 4 6 ll 19 Table 4 LIQUID SEPARATION FROM LATHER GENERATED \VITH SOLUTIONS CONTAINING 0.05 GRAM SODIUM: LAURYL SULFOACETATE AND 0.45 GRAML STABILIZ- ING AGENT PER 100 00. OF SOLUTION Elapsed time in minutes Solutions containing:

No stabilizing agent ll 25 29 32 35 35 36 38 Sodium octyl sullate 2 4 8 12 17 20 27 30 Sodium octyl sulfoacetate 0 1 3 5 8 13 20 Composition of 100 parts of 5 solution Tub 'lurbidityd agg Solution appeare No. Sodium on gg lauryl hexyl Water coolmg heating sullo- Sun-m to acetate acetate C'. C. 26 74 53 70 90 36 10 16 74 2 21 l0 10 80 6 26 10 5 85 10 29 5 95 10 30 2 3 95 2 18 3 2 95 2 S7 Solution No. 1 above, a 26% solution of sodium lauryl sulfoacetate in water, on being cooled slowly, becomes slightly turbid at about 53 C., milky and thick at about 35 0., pasty at about 27 C., and solid at about C. When heated slowly, the mass becomes clear liquid at about 70 C.

The results recorded in the foregoing table show the surprising efiect which the addition of a stabilizing agent composed of sodium 2-ethylhexyl sulfoacetate has on the turbidity points of aqueous solutions of a representative alkyl ester salt, sodium lauryl sulfoacetate. Because of this efiect, aqueous solutions of sodium lauryl sulfoacetate which remain clear at low temperatures may be prepared containing an amount of sodium lauryl sulfoacetate such that, in the absence of the sodium 2-ethyl-hexyl sulfoacetate, the solutions would become turbid at a relatively high temperature.

EXAMPLE 5.-In a manner similar to that described in Example 4, a mixture of 10 per cent sodium lauryl sulfoacetate, 16 per cent sodium 2-ethyl-hexyl sulfate, and 74 per cent water was made.= It showed no turbidity at -7 C.

EXAMPLE 6.Aqueous solutions containing the specified quantities of sodium lauryl sulfoacetate, stabilizing agents and water shown in the following table were prepared. The temperatures in degrees centigrade at which turbidity appeared on cooling'and at which turbidity disappeared on warming the turbid liquids were determined. The results obtained are summarized in the following table: I

9 parts of sodium lauryl sull'oacetate dissolved with- Parts stabilizingagont 0 9 18 36 Parts water 91 82 73 Total parts =l00.

Temperature in degrees oentigrade at Nature of stabilizing which humansagent Ap. Dis. Ap. Dis. Ap. Dis. Ap. Dis.

Sodium secondary hexyl sulioacetate 20 35 13 32 2 22 0 8 Sodium heptyl sulloacetate 20 35 20 31 13 31 8 28 Sodium 2-ethyl-hexyl sulfoaoetate 20 35 1 22 3 15 35 46 Sodium 2-ethyl-hexyl sulfate 20 35 2 l8 2 0 8 3 Sodium 2'-Ethyl-hexyl sulfobutyrate i. 20 35 2 28 2 22 7 8 Sodium n-hexyl sulloacetate 20 35 4 41 6 l8 9 4 Sodium n-ootyl sulioacetate .s 20 35 2 39 2 ,34 3 10 Ap.=appeared. Dis.=disappeared.

This example illustrates the efiects of the specified stabilizing agents in reducing the tur- ,bidity points of-aqueous solutions of a long-chain alkyl ester salt; in this case, sodium lauryl sulfoacetate. It also shows that the compounds composing the stabilizing agents, although they exhibit the valuable propertieshereinbefore pointed out in an important degree, differ one from another in particular cases. Because of this fact, in preparing the compositions of the present invention, it is advisable to select the stabilizing agent and its proportion with a view to the specific properties which it compositions possess.

As already stated, as a general rule, the addition of a stabilizing agent to a concentrated aqueous solution of a long-chain alkyl ester'salt first decreases the viscosityof the solution and then, as the amount of the stabilizing agent in the solution is increased, the viscosity of the solution is increased. The following example offers specific illustrations of the effect of the stabilizing agents on the viscosities of an aqueous solution of an alkyl ester salt.

EXAMPLE 7 .An aqueous solution, containing 9 parts of sodium lauryl sulfoacetate and 91 parts water was warmed to about 32 C. and transferred to a 25 cc. pipette in which it was allowed to cool to 30 C. The time in seconds required to run the solution out of the pipette from the 25 cc. mark was noted. In the same manner, other solutions which contained 9 parts of sodium lauryl sulfoacetate and specified amounts of stabilizing agents and water were made, and times in seconds required to run 25cc. portions of the respeois desired to have the acetate and 10 parts ammonium sulfate.

tive solutions at 30 C. from the pipette were noted. The time intervals thus recorded indicated the relative viscosities of the several solutions. The results obtained are recorded in the following table:

Tested solutions contained 9 parts of sodium lauryl sulfoaoetate and- From the results recorded in the above table, it will be seen that by the proper selection of a stabilizing agent, and the use of it in the most desirable proportions in relation to the alkyl ester salt, it is possible to prepare solutions having viscosities greater than the viscosity of the aqueous solution of the alkyl ester salt in the absence of the stabilizing agent.

The following examples illustrate preferred compositions of the invention containing a proportion ofstabilizing agent within the limits of about 1 to about 4 .parts by weight of a stabilizing agent for each part by weight of the alkyl ester salt. The com-positions also contain a highly water-soluble salt which has the effect of increasing the viscosity of the aqueous solutions.

' EXAMPLE 8.-10 parts of commercial sodium lauryl sulfoacetate, identified in Example 1, are mixed with 16 parts sodium 2-ethyl-hexyl sul lffie mixture dissolved in 64 parts water furnishes a concentrated solution which, in terms of flow time as indicated above, has a viscosity requiring 85 seconds of flow for 25 cc, as compared with water which requires 26 seconds, and when the solution is cooled, turbidity appears at C. anddisappears, on warming, at C.

This concentrated solution is especially adapted for use as a shampoo, although it is also valuable for other purposes, such as for the washing of fine fabrics, rugs, and upholstery. It may be handled and stored under the usual conditions without developing turbidity, because of its low turbidity point. I

Exams 9.--10 parts of commercial sodium lauryl sulfoacetate are mixed with 16 parts sodium capryl (secondary octyl) sulfoacetate and 10 parts ammonium sulfate. The mixture dissolved in 64 parts water furnishes a concentrated solution which on cooling develops turbidity at 4 C. and the turbid solution, on being warmed, becomes clear at C. This concentrated solution, similarly to that disclosed in Example 8, is particularly valuable when employed as a shampoo.

The composition of this example, when compared with the composition of Example 8, illustrates the superior properties of the 2-ethyl-hexyl compound as compared with the capryl (secondary octyl) compound; 1. e., while compositions containing, the capryl compound exhibit improved properties as compared with compositions containing the long-chain alkyl ester salts alone, the 2-ethy1-hexyl compound imparts particularly valuable properties to the compositions.

EXAMPLE 10.-A composition containing 8 parts 0., compared with water at 26 seconds; when the solution was cooled, turbidity appeared at 0 C., and when the turbid solution was warmed, turbidity disappeared at 10 C.

The following examples illustrate shampoo compositions of the invention which contain stav bilizing agents composed of a mixture of compounds, a highly water-soluble salt, and a gum:

ExAMPLE 11.-A shampoo composition in the form of an aqueous solution is made by mixing 4 parts of commercial sodium lauryl sulfoacetate with 9 parts of sodium 2-ethyl-hexyl sulfoacetate, 4 parts sodium normal hexyl sulfoacetate, and 2 parts of trisodium citrate crystals, and adding the aqueous solution prepared from 1 part of powdered gum karaya, and parts of Water. The resulting solution has a turbidity point of --4 C. and the turbid mixture clears at 0 C.

EXAMPLE l2.4 parts of commercial sodium lauryl sulfoacetate are intimately mixed with 11 parts of sodium 2-ethy1-hexyl sulfoacetate, 4 parts of sodium Z-ethyl-butyl sulfate, and 2 parts of trisodium citrate crystal This mixture is added to a. solution of 1.2 parts of powdered gum karaya in 77.8 parts of water. The aqueous solution thus formed is adapted for use as a shampoo. It becomes turbid at 4.5 C. and the turbid mixture clears at =0.5 C.

In. place of the long-chain alkyl ester salts, stabilizing agents, and water-soluble salts employed in the foregoing examples, there may be employed in the compositions of the invention any of the other members of these classes of compounds hereinbefore disclosed.

From the foregoing description it will be apparent that the present invention provides compositions having good lathering properties and controlled detergent power. In the form of aqueous solutions, the compositions remain clear over a wide range of temperatures and have good viscosity characteristics. The compositions and their aqueous solutions, therefore, are admirably adapted for use as shampoos and for washing fine fabrics, rugs, and upholstery.

Since certain changes may be made in the compositions disclosed without departing from the scope of the invention, all matter contained in the above description should be taken as illustrative and not in a limiting sense.

We claim:

1. A detergent composition adapted for use as a shampoo comprising an alkali metal salt of a long-chain alkyl ester of a suite aliphatic monocarboxylic acid containing 2 to 4 carbon atoms in the acyl radical and 12 to 18 carbon atoms in the alkyl radical thereof, and for each part by weight of said alkali metal salt of a long-chain alkyl ester, at least three-fourths part by weight of a 1 stabilizing agent composed of at least one compound which is an alkali metal salt of a monoallwl ester of an acid selected fromthe group consisting of sulfuric acid and sulfo aliphatic mono-carboxylic acids containing 2 to 4 carbon atoms, said monoalkyl ester salt containing 5 to 11 carbon atoms but not more than 9 carbon atoms in a straight chain in the alkyl radical thereof.

2. A detergent composition adapted for use as a shampoo comprising an alkali metal salt of a long-chain allgvl ester of sulfoacetic acid containing 12 to 18 carbon atoms in the alkyl radical thereof, and for each part by weight of said alkali metal salt of a long-chain alkyl ester threefourths to ten parts by weight of a stabilizing agent composed of at least one compound which is an alkali metal salt of a monoalkyl ester of sulfoacetic acid containing to 11 carbon atoms but not more than 9 carbon atoms in a straight chain in the alkyl radical thereof.

3. A detergent composition adapted for use as a shampoo comprising an alkali metal salt of a long-chain alkyl ester of sulfoacetic acid containing 12 to 18 carbon atoms in the alkyl radical thereof, and for each part by weight of said alkali metal salt of a long-chain alkyl ester threefourths to ten parts by weight of a stabilizing agent composed of at least on compound which is an alkali metal salt of a monoalkyl ester of sulfuric acid containing 5 to 11 carbon atoms but not more than 9 carbon atoms in a straight chain in the alkyl radical thereof.

4. A detergent compositionadapted for use as a shampoo comprising sodium lauryl sulfoacetate, and for each part by weight of said sodium lauryl sulfoacetate one and one-half to five parts by weight of a stabilizing agent composed of at least one compound which is an alkali metal salt of a monoalkyl ester of an acid selected from the group consisting of sulfuric acid and sulfo aliphatic mono-carboxylic acids containing 2 to 4 carbon atoms, said monoalkyl ester salt containing 6 to 8 carbon atoms in the alkyl radical thereof.

5. A detergent composition adapted for use as a shampoo comprising an alkali metal salt of a long-chain alkyl ester of sulfoacetic acid containing 12 to 18 carbon atoms in the alkyl radical thereof, for each part by weight of said alkali metal salt of a long-chain alkyl ester one and one-half to five parts by weight of a stabilizing agent composed of at least one compound which is an alkali metal salt of a monoalkyl ester of an acid selected from the group consisting of sulfuric acid and sulfo aliphatic mono-carboxylic acids containing 2 to 4 carbon atoms, said monoalkyl ester salt containing 5 to 11 carbon atoms but not more than 9 carbon atoms in a straight chain in the alkyl radical thereof, a highly watersoluble salt selected from the group consisting of ammonium sulfate, sodium citrate, sodium tartrate, and sodium malate, and a gum selected from the group consisting of gum karaya, locust bean gum, and gum tragacanth.

6. A detergent composition adapted for use as a shampoo comprising an aqueous solution of a sodium salt of a long-chain alkyl ester of a sulfo aliphatic mono-carboxylic acid containing 2 to 4 carbon atoms in the acyl radical and 12 to 18 carbon atoms in the alkyl radical thereof, and for each part by weight of said sodium salt of a long-chain alkyl ester one and one-half to five parts by Weight of a stabilizing agent composed of at least one compound which is an alkali metal salt of a monoalkyl ester of an acid selected from the group consisting of sulfuric acid and sulfo aliphatic mono-carboxylic acids containing 2 to 4 carbon atoms, said monoalkyl ester salt containing 5 to 11 carbon atoms but not more than 9 carbon atoms in a straight chain in the alkyl radical thereof, said aqueous solution having a total concentration of said sodium salt of a longchain alkyl ester and said stabilizing agent of 5 to 50 per cent.

7. A detergent composition adapted for'use as I a shampoo comprising an aqueous solution of an by weight of said alkali metal lauryl sulfoacetate at least three-fourths part by weight of a etabilizing agent composed of at least One compound which is an alkali metal salt of a monoalkyl ester of an acid selected from the group consisting of sulfuric acid and sulfo aliphatic mono-carboxylic acids containing 2 to 4 carbon atoms, said monoalkyl ester salt containing 5 to 11 carbon atoms but not more than 9 carbon atoms in a straight chain in the alkyl radical thereof, said aqueous solution having a total concentration of said alkali metal lauryl sulfoacetate and said stabilizing agent of 5 to 50 per cent.

8. A detergent composition adapted for use as a shampoo comprising an aqueous solution of sodium lauryl sulfoacetate, a highly water-soluble salt selected from the group consisting of ammonium sulfate, sodium citrate, sodium tartrate, and sodium malate, and for each part by weight of said sodium lauryl sulfoacetate threefourths to ten parts by weight of a stabilizing agent composed of at least one compound which is an alkali metal salt of a monoalkyl ester of an acid selected from the group consisting of sulfuric acid and sulfo aliphatic mono-carboxylic acids containing 2 to 4 carbon atoms, said monoalkyl ester salt containing 6 to 8 carbon atoms in the alkyl radical thereof, said aqueous solution having a total concentration of said sodium lauryl sulfoacetate and said stabilizing agent of 5 to 50 per cent.

9. A detergent composition adapted for use as a shampoo-comprising an aqueous solution of sodium lauryl sulfoacetate, a salt selected from the group consisting of ammonium sulfate, sodium citrate, sodium tartrate, and sodium malate, and a gum selected from the group consisting of gum karaya, locust bean gum, and gum tragacanth, and for each part by weight of said sodium lauryl sulfoacetate one and one-half to five parts by weight of a stabilizing agent composed of at least one compound which is a sodium salt of a monoalkyl ester of an acid selected from the group consisting of sulfuric acid and sulfo aliphatic mono-carboxylic acids containing 2 to 4 carbon atoms, said monoalkyl ester salt containing 6 to 8 carbon atoms in the alkyl radical thereof, said aqueous solution having a total concentration of said sodium lauryl sulfoacetate and said stabilizing agent of 10 to 35 per cent.

10. A detergent composition adapted for use as a shampoo comprising an aqueous solution of sodium lauryl sulfoacetate, a salt selected from 'alkali metal lauryl sulfoacetate, and for each part the group consisting of ammonium sulfate, sodium citrate, sodium tartrate, and sodium malate, and for each part by weight of said sodium lauryl sulfoacetate one and one-half to five parts by weight of sodium 2-ethy1-hexyl sulfoacetate, said aqueous solution having a total concentration of said sodium lauryl sulfoacetate and said 2-ethylhexyl sulfoacetate of 10 to 35 per cent.

11. A detergent composition adapted for use as a shampoo comprising an aqueous solution of about 4 parts by weight of sodium lauryl sulfoacetate, about 9 parts by weight of sodium 2- ethyl-hexyl sulfoacetate, about 4 parts by weight of sodium normal hexyl sulfoacetate, about 2 parts by weight of trisodium citrate, and about 1 part by weight of gum karaya, said aqueous solution having a total concentration of saidv sodium lauryl sulfoacetate, said sodium 2-ethyl-hexyl sulfoacetate, and said sodium normal hexyl sulfoacetate of 10 to 35 per cent.

GILBERT C. TOONE. LAWRENCE H. FLE'II.

' Patent No. 2,516,19h.

CERTIFICATE OF CORRECTION.

April 15, 19M.

GILBERT c. T001133, ET AL.

It is hereby certified that error appears in the printed specification oi the above mnnbered patent requiring correction as'follows: Page Z'Qfirst column, line 11, for "blow" read -below--; line M5, for "therefor" read --therefore-; page 5, second column, line 14.5, for "from 16" read '--from 15-; line 51 after lower strike out con-"g line 52, before concentrated" strike out highly; same line, aiter "from" insert --5 per cent to--; page 11., first column, line 69, for 'fhaving" read --have--; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of June, A. D. 19,15.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

' Patent No. 2,516,19h.

"the same may conform to the record ofthe CERTIFICATE or CORRECTION.

April 15; 19h}.

GILBERT c. room-g, ETIAL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction aafollows: Page 2', first column, line 11; for blow read --below--; line 145, for- "therefor" read line 11.5,for ffrom l6" read'--from l5-- lihe 51, after "lower" strike out-com; line 52, before "concen- 'trated" strike out "highly"; same line, after "from" insert --5 per cent to----; page 11., first column, line 69, for "having" read --he.ve--; and that the said'Le tters Patent should be read with this correction"therein that case in the Patent Office.

-therefore--; page 5, second column,

Signed and sealed this 15th day r June, A. D. 19h}.

Henry Van Arsdale,

(Seal) Acting Commissioner of Patents.