US2863836A - Detergent composition of improved foam performance - Google Patents

Description

2,863,836 DETERGENT COMPOSITION OF IMPROVED FOAM PERFORMANCE Richard D. Stayner, Berkeley, Calif., assignor to California Research Corporation, San Francisco, Calif., a

corporation of Delaware No Drawing. Application September 23, 1955 Serial No. 536,265 3 Claims. (Cl. 252-152) This invention relates to anionic sulfated synthetic detergent compositions having improved properties.

Although the exact relationship between foaming and detergency of anionic sulfated synthetic detergents is not known, the formulators preparing detergent compositions intended for use in agitator-type washing machines strive to impart the best foam performance to these compositions, that is to aqueous dilute solutions thereof. These desirable foam characteristics are: (1) good quality, which means a foam texture of uniformly small-sized bubbles having a white, lather-like consistency; (2) stability in the presence of soil; (3) persistence under agitation in the bowl of a washing machine, particularly when the same detergent solution is employed repeatedly (that is, in a multiplicity of washing cycles); and (4) high mechanical stability resulting in a slow decay rate.

To impart simultaneously good quality, stability and persistence to the foam of a conventional dilute aqueous washing solution of an anionic detergent formulation is definitely not a simple task, and its realization, without detracting at the same time from the detergent or cleansing property of the formulation, would promise a substantial expansion of the popular demand for anionic sulfated synthetic detergent formulations.

I have found that the foam performance of a large group of organic sulfate detergents, namely, of those which contain in their molecular structure a straight saturated C C hydrocarbon chain, can be surprisingly and significantly enhanced by adding to these sulfate detergents a mixture or blend of a particular fatty acid amide and a particular kind of a p-acyl phenoxy compound in certain critical weight ratios, namely from 3 to 0.3 parts of the p-acyl phenoxy compound to 1 part of the fatty acid amide, and preferably from 2:1 to 1:2.

The effective fatty acid amide component of the blend to be added to the organic sulfate detergent for the purpose of improving its foam performance in agitated aqueous solutions thereof is a primary amide of palmitic and/ or myristic acid (palmitamide and/ or myn'stamide).

The other component of the blend is a p-acyl phenoxy compound of the general formula:

in which R is a straight C C saturated hydrocarbon chain and A is a radical from the group consisting of hydroxy, oxyethanol and oxethoxyethanol radicals. In other words, this component may be a straight-chain C C saturated p-acyl phenol, or a monoethylene glycol or a diethylene glycol ether of such a phenol. e

The organic sulfated detergents, whose aqueous solutions exhibit improved foam performance on addition thereto of the aforementioned blend of the fatty acid amide and the p-acyl phenoxy compound, are those which contain in their hydrophobic portion a straight Cpl-C1 ice genation techniques. Since the detergent alcohol sulfates of this kind ordinarily produce an inadequate volume of foam or suds in agitated dilute aqueous solutions, in order to enhance the foam volume they are combined with the well-known water-soluble detergent C -C monoalkylbenzene sulfonates, as exemplified by C -C polypropylene benzene sulfonates, preferably in proportions from about 50% to as high as about 85% of the combined weight of the organic sulfate and sulfonate detergents. Furthermore, the compositions improved in accordance with the invention may contain conventional watersoluble inorganic salt detergent builders, such as sodium sulfate, sodium tripolyphosphate, tetrasodium pyrophosphate, sodium silicate, borax, sodium carbonate, etc. The total amount of these builders-may range from 40% to 90% of the combined weight of organic sulfate and sulfonate detergents in the formulation, without adversely affecting the desirable action of the foam-improving blend saturated hydrocarbon chain which can be interrupted by groups such as -O, C(O)O, -C(O)NH etc., and particularly Water-soluble organic straight-chain C C alcohol sulfates, preferably derived from materials such as tallow by conventional hydrolysis and hydro and without detracting from the detergent property of the final formulation. Additionally, conventional additives, such as extenders (e. g., carboxymethyl cellulose), optical bleach, emollients, perfume, dyes, anti-caking agents, etc., may be added to the detergent formulations in amounts which, as a rule, do not exceed all in all 5% by weight.

The aforementioned foam-improving blend is particu larly effective when employed in the detergent formulations in amounts ranging from about 5 to about based on the weight of the detergent organic sulfate component.

The improved detergent compositions of the present invention can be formulated by employing any suitable known technique of the art. Detergent organic sulfates, and in particular straight-chain C14-C13 alkyl (alcohol) sulfates derived from tallow by hydrolysis and hydro genation procedures, may be combined with detergent alkyl benzene sulfonates, inorganic salt builders and other desired conventional additives in the proportions indicated hereinbefore and with the foam-improving blend in accordance with the invention. Preferably, the several ingredients are combined to form a solution or a slurry, whereupon the resulting mixture is dried to give a particleform product characterized by a substantially uniform distribution of all of the ingredients within each individual particle.

Often it may be preferred to prepare first the alkyl benzene sulfonic acid by sulfonating a suitable alkyl benzene stock with an excess of concentrated sulfuric acid or oleum and then to add to the sulfonation reaction mixture the sulfatable component, e. g., molten or flaked C -C aliphatic alcohols derived from hydrogenated tallow fatty acids, or molten or flaked C C alkylolamides of 0 -0 straight-chain saturated fatty acids. By employing an appropriate quantity of the sulfonating agent, the desired weight ratio of detergent organic sulfate to alkyl benzene sulfonate is achieved in the final neutralized sulfate-sulfonate product slurry. Thereafter, the foam-improving agent prepared as a blend according to the invention, detergent builders and other additives which may be required, are introduced into the slurry, and this latter is dried to the solid particle form, or processed to yield a paste, or diluted to form a liquid concentrate.

A typical detergent formulation, from 20 to 22% by weight of which consisted of detergent straight-chain C C alkyl sulfates, alkyl benzene sulfonates and the foam-improving agent of the invention was tested in a conventional agitator-type domestic washing machine.

The alkyl sulfate component of this formulation con' sisted of sodium C -C alkyl sulfates prepared by neutralizing sulfated alcohols derived from hydrogenated tallow fatty acids, the larger proportion (60 to 70% by weight) being sodium C alkyl sulfates. The alkyl benzene sulfonate component consisted of sodium C -C polypropylene benzene sulfonates produced in accord- .ance with the teaching of U. S. Patent 2,477,383 to A. H. Lewis. The weight ratio of the alkyl sulfate component to the alkyl benzene sulfonate component in this formulation was about 1:1. The foam-improving agent in all test runs was present in an amount equal to about 2% by weight of the total formulation. The formulation was furthermore built by employing 30% of sodium tripolyphosphate, 20% of tetrasodium pyrophosphate, 5% of liquid commercial N" grade sodium silicate, the balance to make up 100% by weight being essentially solium sulfate.

Dilute solutions of 0.3% concentration of this formulation in soft water (50 p. p. m. of calciummagnesium hardness calculated as calcium carbonate and magnesium carbonate in the weight ratio .of 2:1) at a temperature of 120 F. were employed in the tests. The bowl of the machine, containing the test solution in an amount corresponding to the ration specified therefor by its manufacturer, received a charge of cotton towels (6 pounds) soiled with a specified amount of lard oil. The lid of the bowl was closed and the machine was run the first cycle of ten minutes. Upon stopping the machine, the foam height in inches and the quality of the suds were noted. More lard oil in the same amount as in the first cycle was added to the towels, and the ten-minute operating cycle was repeated six times. At the end of each cycle, the foam height and the quality of the suds were observed and the same amount of lard oil added. In the sixth and seventh cycle, however, lard oil was added in the amount which was double of the amount originally applied in cycle 1.

Table I.Cmparis0n of the effect of different foaml'mprow'ng agents on foam performance P-aeyl Phenoxyethanol l Blend (50/50) Foam Additive Foam Foam Height Quality Height Quality 111 in Inches Inches 3.5 White, Stablev 2 White, Stable Lather-like.

0. 5 1. 5 Still white,

stable, creamy, soaplike.

1 Aeyl group derived from coconut oil fatty acids. 2 Blend of p-aeyl phenoxycthanol and palmitamide.

When a monoethylene glycol ether of a p-acyl phenol (the acyl group being derived from coconut oil fatty acids) was the sole foam-improving additive, the foam height was adequate at first (Nos. 1 to 4 cycles), but the suds lacked the desired lather-like quality. Furthermore, on continuing the multiple cycle operation, the suds decayed sooner, so that at the end of the seventh cycle, less than. 0.5 inches of gray, irregular, lacy suds could be observed on the surface of the liquid in the bowl. In contrast to the above, employment of a 50/ 50 blend of palmitamide and monoethylene glycol ether of p-acyl phenol (the acyl group being derived from coconut oil fatty acids) resulted in an adequate head of foam which retained its creamy, soap-like, white texture despite the multiple cycle operation and even at the end of the seventh cycle displayed an uninterrupted, fairly high (1 /2 inches) body of suds above the surface of the liquid in the bowl. The presence of a conventional amount of a hypochlorite bleach (0.005 to 0.03%), added either at the beginning or during the agitation of the solution, does not affect the stability of the foam.

A blend of palmitamide and p-acyl phenol (the acyl group being derived from coconut oil fatty acids) is equally effective as a foam-improving agent, provided hypochlorite bleaches are not employed. Addition of I these bleaches to the solutions prior to the addition of the detergent is found to impair the foam stability.

When the test solution is prepared by using hard water (300 p. p. m. calculated as calcium carbonate and magnesium carbonate in a weight ratio of 2:1), the foam height and the quality of the suds produced by the detergent composition containing the blend of the primary amide and the p-acyl phenoxy compound are superior to those obtained by using the individual components of the blend as the foam-improving agent.

In order to bring out the specificity 0f the fatty acid amides, present as one of the components in the foamimproving agent of this invention, a comparative test series was carried out employing difi'erent fatty acid amides in the same detergent formulation containing a combination by weight) of organic sulfate and sulfonate detergents in a weight ratio of 1:1 as the surface-active matcrial. The foam-improving additives in the amount of 2% by weight of the total solids in the formulation were either the long-chain saturated primary fatty acid amides alone or blends of these amides with a monoethylene glycol ether of p-acyl phenol (the acyl group being derived from coconut oil fatty acids). Builders were present in the same amounts as in the previously described test series. The test solution was prepared by dissolving the detergent formulation to 0.15% concentration in soft water p. p. m. of calcium-magnesium hardness in a weight ratio of 2:1). The bowl of the washing machine containing this solution at a temperature of about F. received a charge (6 pounds) of cotton towels soiled with a specified amount of lard oil. The contents of the Table II.Effect of the presence of diflerent amides in the foam-improving agent P-aeyl Phenoxy- Foam Test. Amide Percent; ethanol Height Foam Quality No. by Wt. in Perin cen t by inches 2 2.8 White, creamy, very stiff, dry. 1 1 3. 4 White, creamy, moderately v stiti, wet. Palmitamide. 2 3.1 Brightly white, dry, crerhny,

very stiti. do 1 1 3.1 White, creamy, moderatelv stiti, wot. Stearam1de.. 2 r. 1.6 White, dry, chalky, very still. 3, 1 do 1 1 2.5 White, wetter than in No. 5, moderately stiff. 7...--- None 3.5 Grey, definitely lat-y texture,

low hulk viscosity. 8 2 White, lacy, lacking in latherllrzc quality.

bowl were agitated in a conventional manner, their average foam height in inches above the liquid level was observed after 2, 5, l0, l5 and 20 minutes of operation.

The results shown in Table 11 indicate that the best suds are obtained by employing the blend of palmitamide and the glycol ether of p-acyl phenol (run No. 4). The foam height lies in the satisfactory range from 2 /2 to 4 inches, while the quality of the foam is unquestionably excellent: it is white, creamy, soap-like and wet, although less stiff than in run No. 3 where palmitamide is the sole foam-improving additive. In this latter instance, although a moderately high head of foam was obtained on the surface of the wash solution, the bulk viscosity was too high, so that the suds were too stiff and rather chalky in appearance. Such suds are diflicult to eliminate after the washing cycle and interfere with proper rinsing.

Myristamide added alone (run No. l), secures a foam which is less dense-bodied (has lower bulk density) than with palmitamide alone, but is still more stiff and drier than when myristamide is added in a blend with the monoethylene glycol ether of p-acyl phenol (p-acyl phenoxyethanol), in which case it contributes to the latherlike quality of foam, almost as good as that secured with the palmitamide blend (run No. 2).

Stearamide employed alone is obviously unsatisfactory; the foam height is low and the foam is dry, stiff and chalky (run No. 5). However, blended with the glycol ether of p-acyl phenol in a 50/50 weight ratio, stearamide gives a higher level of foam which has a wetter character (run No. 6).

Neither lauramide nor arachidamide (alone or in a blend with an acylphenoxyethanol) are satisfactory. The first amide fails to contribute to an improved bulk viscosity of the foam and, therefore, cannot form densebodied, soaplather-like suds; the second causes formation of suds which are altogether. too stiff and chalky and are of an inadequate volume.

Alkylolamides, e. g., stearic ethanolamide and palmitic ethanolamide, reported elsewhere in the art as foam-improving additives, are inferior to palmitamide, whether alone or blended with the glycol ethers of p-acyl phenols. The bubbles of the resulting foam are not creamy like soap suds.

The aforegiven illustrative data clearly bring forth the advantages of introducing the foam-improving blend of the invention into the detergent formulations containing organic sulfated detergents in which the hydrophobic portion is characterized by the presence of a straight C14-C13 saturated hydrocarbon chain. These advantages are greater soil tolerance and higher mechanical stability and persistence under agitation in the presence of soil, being more effective in multiple-cycle operation.

At this point I wish to reiterate that the aforegiven description and examples are offered merely to illustrate the operativeness of the invention, and that the foamimproving blends of palmitamide and/or myristamide with lower molecular weight glycol ethers of p-acyl phenols, or with the corresponding p-acyl phenols, are effective in improving foam characteristics of other similar organic sulfated detergents; for instance, sulfated alkylolamides of straight-chain C C saturated fatty acids, sulfated monoglycerides of straight-chain C -C saturated fatty acids and of many other organic detergent sulfates, in which the hydrophobic portion contains a straight C -C saturated hydrocarbon chain.

I claim:

1. A detergent composition of improved foam performance consisting essentially of, by weight, 15 to parts of a saturated normal C -C alkyl sulfate detergent, 50 to parts of a (l -C monoalkyl benzene sulfonate detergent, and, as foam-improving material, about /2 to 2 parts of saturated normal c -c fatty acid amide per one part of a para-acylphenoxy compound of the formula wherein R is a straight C -C saturated hydrocarbon chain and A is a radical from the group consisting of hydroxy, oxyethanol and oxyethoxy-ethanol radicals, said foam-improving material being present in an amount from about 5% to about 75% based on the sulfate detergent.

2. A detergent composition according to claim 1 wherein the monoalkyl benzene sulfonate detergent is a (Z -C polypropylene benzene sulfonate detergent, the paraacylphenoxy compound is a straight-chain C -C paraacylphenoxy ethanol and the saturated fatty acid amide is palmitamide.

3. A built detergent composition consisting essentially of, by weight, 10 to 40 percent of the composition as defined in claim 1, and 60 to percent of water-soluble inorganic salt builders.

References Cited in the file of this patent UNITED STATES PATENTS 2,383,738 Richardson Aug. 28, 1945 2,477,383 Lewis July 26, 1949 2,519,062 Miskel Aug. 15, 1950 2,768,956 Scott Oct. 30, 1956 2,772,239 Lewis Nov. 27, 1956 FOREIGN PATENTS 157,394 Australia Aug. 23, 1951

Claims (2)

1. A DETERGENT COMPOSITION OF IMPROVED FOAM PERFORMANCE CONSISTING ESSENTIALLY OF, BY WEIGHT, 15 TO 50 PARTS A SATURATED NORMAL C14-C18 ALKYL SULFATE DETERGENT, 50 TO 85 PARTS OF A C9-C18 ALKYL SULFATE DESULFONATE DETERGENT, AND, AS FOAM-IMPROVING MATERIAL, ABOUT 1/2 TI 2 PARTS OF SATURATED NORMAL C14-C16 FATTY ACID AMIDE PER ONE PART OF A PARA-ACYLPHENOXY COMPOUND OF THE FORMULA

3. A BUILT DETERGENT COMPOSITION CONSISTING ESSENTIALLY OF, BY WEIGHT, 10 TO 40 PERCENT OF THE COMPOSITION AS DEFINED IN CLAIM 1, AND 60 TO 90 PERCENT OF WATER-SOLUBLE INORGANIC SALT BUILDERS.