US2956025A - Sulfonate detergent compositions with improved foam characteristics - Google Patents

Description

SULFONATE DETERGENT COMPOSITIONS WITH INIPROVED FOAM CHARACTERISTICS Filed Mar. 22, 1955, Ser. No. 496,080

4 Claims. (Cl. 252-161) No Drawing.

The present invention relates to washing compositions containing anionic synthetic alkyl benzene sulfonate detergents capable of producing stable, good-quality, persistent suds in conventional dilute aqueous washing solutions under conditions of agitation and in the presence of soil.

Alkyl benzene sulfonate detergents, such as are produced in the art by sulfonating (E -C monoalkyl benzenes which have been obtained either by condensing chlorinated parafiins with benzene in the presence of a Friedel-Crafts catalyst, or by alkylating benzene with long branched-chain olefins or olefin polymers having a branched-chain structure, as in polypropylene, likewise in the presence of a suitable catalyst, e.g., HF, are widely employed by laundries and in homes because of their excellent soil-removal characteristics.

However, the foam performance of these sulfonate determents during the washing of soiled clothes and fabrics is far from being as satisfactory as their ability to remove soil. As a matter of fact, although C C branched-chain monoalkyl benzene sulfonates when present in dilute aqueous solutions in the bowl'of a washing machine produce relatively large amounts of suds, these suds are extremely unstable, lacy in texture, and readily break down and disappear under agitation andin contact with soil. This inability to produce stable, satisfactory suds represents a drawback in the eyes of a large fraction of the consumer public who arenot only accustomed to a high, creamy foam of conventional fatty acid soaps and expect the same kind of foam from synthetic detergents, but frequently consider the foam tobe an index of the Washing efliciency and a measure of the quantity of powdered soap or synthetic detergent required for efiicient'washing.

A large number of additives thought likely to improve the foam performance of branched-chain alkyl benzene sulfonate detergents has been proposed-in the past with out succeeding, in most cases, to secure satisfactorytoam characteristics and, in particular, to secure a greater foam stability and a better foam quality, i.e., a texture approximating that of conventional soapsuds. Besides, many of these puroposed additives were relatively expensive and their inclusion in alkyl benzene sulfonate detergent formulations tended to increase unduly the ultimate sales price of these formulations.

Thus, the search for new, inexpensive and eflicient foam-improving agents for alkyl benzene sulfonate detergents continued on unabated.

I have now discovered that by combining detergent As shown later in this specification, the two-component stability and quality. On the other hand, the additionof a C -C straight-chain saturated aliphatic alcohol or a straight-chain c c alkane 1,2-glycol, to the dedetergent branched-chain alkyl benzene sulfonate, while stabilizing the foam of this latter, provides but an inadequate volume of the foam. In fact, the alcohol tends to act as a defoamer and to decrease the formation of foam. It is, therefore, entirely unexpected that the threecornponent combination of a detergent branched-chain alkyl benzene sulfonate, a normal primary C C alkyl benzene sulfonate, and a c c straight-chain saturated aliphatic alcohol, or a straight-chain 0 0 alkane 1,2-glycol, is capable of producing a stable, good-quality, and persistent foam.

In the aforementioned three-component combination, the normal primary C -C alkyl benzene sulfonate can be present in amounts ranging from about 5 to about 50% by weight, Whereas, the alcohol or 1,2-glycol component can be present in amounts ranging from about 2 to about 15% by weight, the balance to make up by weight being the detergent branched-chain alkyl benzene sulfonate. More aliphatic alcohol or glycol in proportions up to 25% by weight may be added, if it is desired, to increase the opacity, whiteness, and bulk density and volume of the foam.

Any suitable effective detergent water-soluble salt of a branched-chain C -C3 monoalkyl benzene sulfonic acid, e.g., an alkali metal, an alkaline earth metal, an ammonium, an alkyl ammonium, and an :alkylol ammonium sulfonate may be employed; Water-soluble C C monoalkyl benzene sulfonates such as are described in U.S. Patent 2,477,383 to Lewis and keryl benzene sulfonates described in U.S. Patent 2,218,472 to Kyrides areLusually preferred. Particularly satisfactory, owing to their excellent soil-removing ability, are branchedchain C C monoalkyl benzene sulfonates, such as polypropylene benzene su'lfonates. Employment of such sulfonate detergent materials made up of predominantly C polypropylene benzene sulfonates is found to be particularly effective, resulting'in'a'n enhanced ivolume of stable, good-quality foam. t

The term a normal primary C -Cm'alkyl benzene sulfonate, as employed throughout this description refers to water-soluble salts of norm-a1 l-phenyl 'C C alkane sulfonic acids having the general formula: RASO M, wherein M is a cation from the group consisting of alkali metal, alkaline earth metal, ammonium, alkyl ammonium, and alkylo'l ammonium cations, R is a straight-chain saturated C -C aliphatic radical, and A is a phenylene linkage.

The effective foam-stabilizing alcohols of the detergent composition of the present invention are straight-chain saturated C C alcohols and straight-chain C -C alkane 1,2-glycols (C C alkanols-and C C alkane 1,2-diols') 'If desired, a fatty acid alkylolamide such as lauric ethanolamide, lauric isopropanolamide or lauiic glycerylamide may be added to the three-component combination of this invention in amounts which may range from about 2' to about 25 by Weight thereof.

The improved foam characteristics of alkyl benzene sulfonate detergent compositions formulated in accordance with the invention are not affected adversely by the presence of conventional water-soluble inorganic salt builders, i.e., neutral salts of strong inorganic acids, such as sodium chloride, potassium chloride, sodium sulfate,

atent filce Patented Oct. 11, 1960 sodium tripolyphosphate, sodium silicate, borax, and the like. From 60 to 90 parts by weight of these inorganic salt builders, preferably as sodium salts, may be present in each 100 parts by weight of a detergent formulation solved in soft water obtained from the laboratory tap and having a hardness of 50 ppm, calculated as calcium carbonate and magnesium carbonate in a weight ratio of 2:1. The temperature of the 0.15% solution containing the three-component combination of the pres- 5 was 120 F., and in each test run 500 ml. thereof was cut invention. placed in a two-liter beaker. The solutions were tested If so desired, other conventionally employed additives at the bench by agitating the contents of the beaker-s such as anti-caking agents, optical bleaches, corrosion with the aid of propeller-type stirrers for one minute, inhibitors, e.g., sodium silicate, perfume and dyes, may whereupon foam height in millimeters was measured and be added in small amounts to the formulation. Carboxythe foam quality and foam stability were observed. methyl cellulose or celluronic acid salts also may be an Fifteen minutes after agitation the foam height, quality ployed in small amounts to prevent redeposition of the and stability were again observed. The stability was soil. Likewise, N-alkyl glycines and diglycines may be rated by observing the rate of foam decay under mechaniadded to prevent occurrence of skin rashes and erythemas. cal stress as by blowing on a small volume of foam All of these additives are introduced in comparatively gently with air. A foam that withstands being blown small amounts, rarely exceeding 5% by weight based on upon without collapse of surface bubbles has Good the total amounts of solids in the formulation, and in all stability. A foam having poor stability rapidly collapses events in such amounts as not to interfere with the imwhen blown upon. Intermediate stabilities are rated as provement of foam performance in accordance with the Fair. A foam characterized by Good quality is made up invention. of uniformly small-sized, dense-bodied bubbles of high Ordinarily, the blending of these several components of bulk viscosity. This foam is white and opaque. Foam the improved detergent composition of the present invenof Poor quality displays large-sized bubbles, has a low tion is carried out in a straightforward manner by mixing bulk viscosity, and tends to be lacy. It is, furthermore, the components to form a solution or slurry, drying this grayish in color and relatively transparent. Foams inslurry to the solid particle-form; or, if so desired, evaptermediate in quality between Poor and Good are rated orating it to form a paste; or, yet, diluting it to produce to be Fair. a liquid concentrate. The data from these representative test runs are tabu- Foarn evaluation bench tests were carried out at the lated in the following table.

Branched- Foam Height Chain Saturated in mm. Test Parts 1 Aliphatic Parts Foam Run n-Alkyl Benzene Sulfonate by Benzene Alcohol by Foam No. (as Na salt)-Name Weight Sulionate Component- Weight bility Quality Detergent Name After After inParts lMin. 15 Min. by Weight 1 None 20 None 87 68 Poor.... Poor. 9 None 20 n-Hexadecanol 2 78 12 do.- Fair. q Nnnp 20 n-Hexadecane 4 83 52 "110... Poor.

1,2-glycol. 4 n-Hexadecyl benzene sul- 2O ne fonate. Less than 10 do.... Do. R dn 20 n-Hexadecnnol.-- 2 Less than 10 Good... Fair. 6 do 1O 10 N 62 0 Poor Poor. 7 n-Tetradecyl benzene sul- 10 10 n-HexadecanoL-.. 3 56 42 Good-.. Good.

11 e. 8 n-Hexadecyl benzene sul- 10 10 ...do.... 0.4 36 do Do.

11 e. Q sec. n-Octadecyl benzene 10 10 ---..d0 2 68 57 Poor Poor.

sulfonate. 10 n-glexidecyl benzene 3111- 10 10 d0 2 50 36 Good. Good.

0113 e. 11 dn 1 19 -.-do 1 82 70 Fair... Fair. 19 rin 5 15 d0 4 33 30 Good Good. H M t r of 11-0 43 alkyl 5 15 n-TetradeeanoL.-- 2 68 57 ..-cio....- Do.

benzene sulfonates 1 d0 5 15 n-O ctadecane 1,2- 2 71 -do.... Do.

g yco nfHexadecyl benzene 5111- 10 10 n-Dodecanol 2 68 42 F001;... Fair.

0118 B 16 do 10 10 n-0ctadecanql... 2 52 30 do. Do.

1 The alkyl portion derived from tallow by hydrogenation and hydrolysis.

laboratory on aqueous wash solutions of the detergent formulations prepared in accordance with the present invention. In these tests, each 100 parts by weight of a solid, dried, particulate detergent composition contained from 20 to 24 parts by weight of the active threecomponent combination of the invention. Sodium C -C polypropylene benzene sulfonate was employed as a typical monoalkyl benzene sulfonate detergent component. A number of representative sodium salts of normal l-phenyl C -C alkane sulfonic acids (sodium n-alkyl benzene sulfonates) were combined therewith together with effective proportions of a normal aliphatic C -C alcohol or a normal C14-C22 alkane 1,2-glycol. Detergent builders were present in the following amounts: 30 parts by weight of sodium tripolyphosphate, 20 parts by weight of tetrasodium pyrophosphate, 5 parts by weight of commercial liquid N sodium silicate, and the remainder to make up 100 parts by weight was sodium sulfate.

The particles of the detergent formulation were dis- In the table, run No. 1 shows that branched alkyl benzene sulfonate detergent produces foam which, although possessing considerable volume, utterly lacks stability and quality, and, consequently, will not persist under agitation in the presence of soil.

Runs Nos. 2 and 3 show that addition of C -C saturated aliphatic alcohols, or C C alkane 1,2-glycols, is incapable of providing stability for the foam of branched alkyl benzene sulfonated detergents.

Run No. 4 indicates that normal primary C -C alkyl benzene sulfonates are incapable of forming a substantial volume of suds which, furthermore, utterly lack quality and stability.

Run No. 5 shows that the addition of a C C saturated aliphatic alcohol fails to impart a satisfactory foam performance to a solution of a normal primary C -C alkyl benzene sulfonate; the volume of foam is so low that the improvement in stability is inadequate to insure foam persistence under agitation.

Run No. 6 illustrates the fact that two-component mixtures of branched-chain alkyl benzene sulfonate detergents with normal primary C C alkyl benzene sulfonates in the absence of an alcohol, or a 1,2-glycol, is incapable of producing stabilized suds which would persist throughout the complete washing cycle in the bowl of a washing machine.

In contrast to the aforementioned runs, test runs Nos. 7, 8, 10, 11, 12, 13 and 14 clearly demonstrate the ability of the active three-component combination of the present invention to create adequate suds of fair to good stability and quality, which persist throughout the washing operation.

Run No. 9 points out the criticality of the bonding of normal alkane groups to the phenylene linkage in the normal primary C C alkyl benzene sulfonates through the terminal carbon. Secondary normal octadecyl benzene sulfonate failed to provide a stable foam, when employed in the three-component combination of the invention.

The detergent formulations prepared in accordance with the invention are highly effective in laundering operations in automatic and non-automatic agitator-type washing machines, their dilute solutions maintaining a persistent level of good quality suds in the machine throughout the complete washing cycle of at least 20 minutes and providing a satisfactory detergency, i.e., efiectively removing the soil from dirty laundry when employed in concentrations of 0.1 to 0.4, comomn to laundry practice.

The improvement in the foam performance of detergent compositions containing active branched-chain alkyl benzene sulfonates, when formulated in accordance with the invention, is entirely unexpected, particularly in view of the fact that neither n-dodecanol, mentioned in the prior art as a foam stabilizer, nor the lower molecular weight saturated aliphatic alcohols, such as decanol, octanol, etc., nor the higher molecular weight saturated aliphatic alcohols containing 18 and more carbon atoms,

e.g., octadecanol, etc., are found capable of improving the foam stability of these sulfonate detergent formulations, In fact, these alcohols tend to act as defoamers.

I claim:

1. A detergent composition consisting essentially, by weight, of 10 to of active organic detergent material and to of water-soluble inorganic salt detergent builders, said organic detergent material consisting essentially, by weight, of about 5 to 50% normal primary C -C monoalkylbenzene sulfonate, 35 to 90% branched-chain C C monoalkyl benzene sulfonate detergent, and 2 to 15% of a normal alcohol selected form the group consisting of C -C saturated primary monohydn'c alcohols and C -C 1,2-glycols.

2. A detergent composition according to claim 1 wherein the alcohol is a saturated primary normal C -C monohydric alcohol.

3. A detergent composition according to claim '1 wherein the normal primary alkyl benzene sulfonate and the branched-chain alkylbenzene sulfonate are sodium sulfonates.

4. A detergent composition according to claim 2 wherein the branched-chain alkylbenzene sulfonate is a C -C branched-chain alkylbenzene sulfonate.

References Cited in the file of this patent UNITED STATES PATENTS 2,166,314 Martin July 18, 1939 2,477,383 Lewis July 26, 1949 2,519,062 Miskel Aug. 15, 1950 2,679,482 Ross May 25, 1954 2,712,530 Baumgartner July 5, 1955 2,746,932 Vitale May 22, 1956 2,768,095 Tadema et al. Oct. 23, 1956 2,770,600 Ricciardi Nov. 13, 1956 2,796,429 Kreps et a1. June 18, 1957

Claims (1)

1. A DETERGENT COMPOSITION CONSISTING ESSENTIALLY, BY WEIGHT, OF 10 TO 40% OF ACTIVE ORGANIC DETERGENT MATERIAL AND 60 TO 90% OF WATER-SOLUBLE INORGANIC SALT DETERGENT BUILDERS, SAID ORGANIC DETERGENT MATERIAL CONSISTING ESSENTIALLY, BY WEIGHT, OF ABOUT 5 TO 50% NORMAL PRIMARY C10-C18 MONOALKYLBENZENE SULFONATE, 35 TO 90% BRANCHED-CHAIN C9-C18 MONOALKYL BENZENE SULFONATE DETERGENT, AND 2 TO 15% OF A NORMAL ALCOHOL SELECTED FROM THE GROUP CONSISTING OF C14-C16 SATURATED PRIMARY MONOHYDRIC ALCOHOLS AND C14-C22 1,2-GLYCOLS.