US2944028A - Sulfonate detergent compositions - Google Patents

Description

, ,W 2,944,028, SULFONATE DETERGENT coMrosmoNs j Richard D. staynenberkeley, Calif.,"assignor to California Re'searchjCorporation, jfia'n Francisco, Calif, a

. corporationoflDelaware This invention relates to improved washing formulations 1 weakv and lacy and rapidly collapse and disappear during the agitation of the contents of the tub containing the washing solution and the soiled articles. This constitutes a serious drawback since a considerable proportion of the consumer publicstill believe that a large volume of suds ;is concomitant with the washing efliciency and gives an rndicatlon of the amount of the detergent necessary for 3 effective washing.

.zTfliS deficiency with respect to theability of producing V persistent suds is noted only in using solutions of poly- @propylcne benzene sulfonates derived from propylene which containa branched-chain polypropylene benzene 1 sulfonate as their active detergentfcomponent, and which arecapableof producing a large. volume of stable suds maintaining a satisfactory highslevel in the continuously agitated aqueous solutions thereof in the presence of soil. C -C polypropylene benzene sulfonates, which may be also designated as sulfonated monophenyl-substituted acyclic C -C polypropylenes are known in the art to beeffective detergents and, when suitably formulated, are

used in a variety of industrial and household cleaning applications, particularlyin the washing of soiled clothes, fabrics and dishes. A-number of'washing formulations, based on these polypropylene benzenesulfonate detergents and containing different additives for the, purpose of modifying one or another particular property of these detergents, have been described in the art. In U.S. Patent 2,712,530, Baumgartner proposed to add to these detergent sulfonates from 5 to 50% by weight of a secondary alkylary-l sulfonate ofthe general structural formula in which R was a straight-chain Ci-C alkylgroup, R"

was a straight-chain Cg-C14 alkyl group, the sum of R and R" equalled 9 to 15 carbons and M was an alkali metal. The addition of this secondary alkyl benzene sulfonate was said' to improve the detergent property of the polypropylene benzene sulfonate at concentrations below about 0.25%

British Patent No. 702,013 disclosed the addition to C -C polypropylene benzene sulfonate detergents of at least by weight of sulfonated 2-phenyl alkanes containing a straight alkyl chain of 10 to 16 carbon atoms in their alkane portion for the purpose of reducing the caking tendency of the formulations containingthe aforementioned detergent polypropylene benzene sulfonates as their main active component.

. In his U.S. Patent 2,477,383, Lewis described detergent branched-chain polypropylenebenzene sulfonates (sulfonated mono-phenyl substituted acyclic polypropylenes), pointingout that commercial: polypropylene benzene snlfonates characterized by an average contento'f about 12 barbonatorns in the polypropylene chaiiiwere particularly effective as detergent ingredients in formulations employed for a great manyhousehold and industrial applications. It'has been noted in the. actual practice that dilute soft water solutions of these commercialC '(dodecyl) polypropylene benzene sulfonate detergents, when employed. in the tub of agitator-type washing machines at low-use concentrationstof the order of 0.15%) and attemperatures above 100 F., and usually from about 120 to about 1410" F.,- generally fail to produce an adequate volume of persistent suds, lasting the entire periodbfagitation and, particularly, in contact with soil (soiled clothes, etc.) Although the volume of suds initially produced on starting the washing cycle is relatively large, these suds are tetramer fractions, such as commercial dodecyl benzene sulfonate It is clearlyin contrast with thefoam perforrm ance of polyprop ylen'e' benzene sulfonates derived from propylene pentamer fractions characterized by an aver-Q age content of about 15 carbon atoms, the solutions of which produce adequate and persistent suds, and which therefore need not be improved as regards their foam per-.

formance.

A number of additives and of combinations of additives 5,; have been proposed in the past for the purpose of im-, proving the foam'performance of commercial C poly- I propylene benzene sulfonatesl However, in most cases, these additives failto secure, in warm soft water solutions ofthe1 polypropylene benzene sulfonatefietergents a sat- 1 isfactory'foar'n which would persist under' continued agitation in the presence of soil. The term soft water, as em ployed in this description 'designateswater of a Ca-Mg hardnessfrom about 50 to less than about ppm, calculated as parts per million of CaCO and MgCO in 3 a, weight ratio of about 2:1. Furtherm0re, most of the proposed additives were comparatively expensive and their employment resulted in an undue increase of the sales price of the final detergent formulations.

It is therefore the object of the present invention to provide a new and inexpensive foam-improving agent for commercial C polypropylene benzene sulfonates, capa ble of assuring persistence of the suds formed by dilute washing solutions of these detergent sulfonates under agitation and in the presence of soil.

I found that the persistence of the suds produced by dilute solutions of commercial C polypropylene benzene I sulfonates can be markedly and unexpectedly enhanced. by combining these detergent sulfonates with effective proportions of an improving agent from the group of straightchain alkyl benzene sulfonates characterized by the gen eral formula V SOaM inwhich n is an integer from 5 to 7, n is an integer from 5 to 8, and M is selected from thegroup consisting of? alkalimetal and ammonium cations. As examples of. these straight-chain alkylbenzene sulfonates, there may: be mentioned: 7-phenyl tetradecane sulfonate, 8.-phenyit hexadecane sulfonate, 9-phenyl"octade'cane sulfonate and: the like. When a sulfonate having a structure correspond, ing to this formula is added to-a' commercial C poly-g propylene benzene sulfonate detergent, dilute aqueous solutions of the resulting combination in conventional low-. use concentrations from about 0.1 .upto about 0.2% form: large volumes of suds, and these suds'persist above the surface of the solution in'the tube of a washing machine; notwithstanding the continued agitation of the contents of; the tub and notwithstanding the presence therein of soiled I clothes or fabrics.

Patented July 5, 1960 based on the total weight of sulf'ona-tes inthe detergent composition.

This improvement in the foam persistence of commercial C polypropylene benzene sulfonate detergents is entirely unexpected and specific to the groupof alkylbenzene sulfonate additives described hereinbefore. The

length. of the alkyl chain and the point of attachment to the aromatic (benzene) ring in the molecule of the sulfa-- nat'e additive are critical tothe production of an adequate and persistent layer of suds above the liquid surface in the tub. This specificity is surprising because'nei-ther the sulfonate detergency improvers of' the aforementioned Bau'mgartner patent, such as 6-phenyl dodecane sulfonate, nor the sulfonat'ed- Z-phenyl alkane caking preventives'of British Patent 702,018, for instance, Z-phenyl dodecane andtetradecane sulfonates, are capable of providing the desired persistent suds above the liquid level in the tub of an agitator-type washing machine.

The presence of the foam-improving additive of the invention does not detract in any way from the excellent soil-removing ability (detergency) of the C polypropylene benzene sulfonates.

The polypropylene benzene sulfonate detergents which have an averageof twelve carbon atoms in the polypropylene chains and the foam persistence of which is enhanced by their combination with-the aforementioned sulfonate additive, are generally employed in the form of water-soluble alkali metal and ammonium salts, sodium salts being preferred. Heavy-duty formulations based on these C polypropylene benzene sulfonates usually contain from about 20 to. about 35% of the, sulfonates by weight of the. total solids. in the formulation.

Formulations containing these detergent commercial C polypropylene benzene sulfonates in combination with from 5. to 50% by weight of thesulfonate additive for achieving foam persistence may contain conventional Water-soluble inorganic salt detergent builders, such as. salts of stronginorganic acids, exemplified by sodium sulfate, sodium chloride and potassium. chloride, ammonium; sulfate and/or alkaline salts of weak inorganic acids, exemplified by various polyphosphates, for instance,

tetrasodium pyrophosphate, sodium tripolyphosphate, so-

dium hexametaphosphate, and salts, such as sodium carbonate, sodium silicate. and borax. From. 60 to 90 parts by weight ofthese inorganic salt detergent builders, prefer-' ably as sodium salts, may be present in each 100- parts by weight of a detergent formulation containing the two aforementioned sulfonates (detergent and additive) in accordance with the invention. Where heavy-duty formulations are prepared, from about 10 to about 90% by weight of the inorganic salt. builders may consist of inorganic polyphosphates, such as Na P O and Na P O and the like. Fatty acid alkylolamides such as lauric isopropanolamide and lauric ethanolarnide known in the art to enhance the tolerance of the foam with respect to soil, may also be included in the detergent formulations of this invention inconventional small quantities. Other. conventional additives, such as carboxymethylcellulose and oxidized cellulose (celluronic acid) organic builders or extenders, anti-caking agents, optical bleaches, cor1'o sion inhibitors, perfume, dyes and skin emollients, such asalkyl glycines, may be employed in the sulfonate detergent formulations. of the. present invention, the total weight of these various additives seldom exceeding 5% by weight of the entire amount of solids in a formulation, and, in all events, being such that the presence of these additives does not interfere with the improved persistence,

of the suds produced by the. agitated dilute solutions of,

the detergent formulations.

The preparation of the detergent formulations of this invention may be effected by blending the detergent C polypropylene benzene sulfonates with the sulfonate additive for the improvement of foamv persistenceinto an,

aqueous slurry, or solution, adding the desired builders and other additives to the slurry, and reducing this slurry by drying, if necessary, to the desired form (liquid concentrate, paste or solid particle).

Another way of preparing, the, detergent formulations of the present invention consists in blending the C polypropylene benzeneswith. from about.- 5. to, about 50%} by weight thereof, of suitable. mono-phenyl. substituted.

straight-chain. alkanes and then. sulfonating the, resulting hydrocarbon blend with the aid. of an appropriate sulfjonating agent, such as fuming sulfuric acid, neutralizing the sulfonation product mixture, introducing into the resulting neutralized; slurry the desiredbuilders and other additives and, finally, reducing the slurry to the desired form, such as liquid concentrate, paste or solid particle.

The improvement in the foam persistence was re peatedly observed by'preparing dilute aqueous, solutions of different detergent formulations containing in their or ganic active portion a blend of- C polypropylene benzene sulfonates and of from 5 to 50% by weight. of straight chain alkylbenzene sulfonates of the previously given formula V and testing; these solutions in an agitator-type automatic washing machine under the conditions approximating thoseof actual household laundering practice. The results of the tests werecompared with the results of numerous test runs which employed detergent formulations contain:

. .ing blends of the C polypropylene benzene sulfonate detergents with straight-chain alkylbenzene sulfonates other than those defined by the aforegiven formula, and also with the results of test runs in which no sulfonate additive was blended with the polypropylene benzene sulfonate detergent component. The solutions for the tests were prepared by using water of 50 ppm. hardness, the

hardness being figured as parts per million of CaCO and MgCO hardness in a weight ratio of 2:1.

The tub of the machine was filled with water, and

a specified quantity of soil thoroughly distributed therein,

followed by such a quantity of. the detergent formulation as to give a 0.15% concentration in the water. Thereafter, a charge of clean cotton towels was placed in the tub assuring aneven distribution below the surface of .the solution which had a temperature of about F. The agitation was, commenced and the level of the suds .was added to the wash solution, and the run resumed for 5' minutes more to complete the 20 minute cycle.

'Persistence of the suds was rated as follows: When suds lasted through a complete washing cycle of 20 minutes, or even longer, and presented a substantially unbroken blanket of foam of /2 or more above the surface of the liquid in the tub, their persistence was rated to be Good. When suds lasted through the whole washing cycle but rose to less than /2" above, the liquid surface and did not. cover the entire surface of the washing solution, the persistence was rated to be Fair." Finally, when practically no suds were formed or, if formed, the suds disappeared before the completion of they washing cycle, the persistence was rated to be Poor.

In an illustrative test series, a representative formulation contained 20 parts of sodium polypropylene benzene sulfonate. having an average of 12 carbon atoms in the polypropylene chain, B'Oparts .of sodium tripolyphosphate,

stance 3 parts by weight of the polypropylene benzene sulfonate detergent by the sulfonate additive, and used in the tests as described hereinbefore.

Representative data from this test series are tabulated on the following page.

and data are merely illustrative of the present invention, and that it may be modified without substantial departure from the spirit and scope thereof, provided that the modifications fall within the scope of the following claims:

-I claim: V V

1. A detergent composition consisting essentially of a. water-soluble polypropylene benzene sulfonate detergent having an average carbon content in the polypropylene V 10 chain of about 12 carbon atoms, and, in an amount suf- Suds persistence evaluation data Commercial Cu Polypropyl- Parts By Suds Per- Test Run No. one Benzene Sultanate Desulfonate Additive Weight sistence tergent in Parts By Weight Addl- Rating tive 1 20 None Poor. 2 2a do r. Do. 3 17 l-phenyl tetradecane sulfonate- 3 Do. 4 30 l-phenyl octadecane sulfonate.-. 3 Do. 1 5 17 2-pheny1 hexadecane sulfonate 3 Fair.

6 17 6 phenyl dodecane sulfonate- 3 Poor. 7 17 ll-phenyl doeosane sulfonate- 3 Do.

a 9n Q-phenyl octadecane sulfonate"--- 1 Fair. 9 17 do 3 Good. 10 17 S-phenyl hexadecane su1fonate. 3 Do. 11 17 7-phenyl tetradecane sulfonatm 3 Do. 12 7-phenyl tetradecane sulfonate. 10 Do. 13 G15 (pentamer) polypropylene None"; Do.

benzene sulfonate 20. r

The data shown in the table clearly indicate the remarkable improvement in the foam persistence of dilutev aqueous solutions of the formulations containing C polypropylene benzene sulfonate detergents, under the conditions of agitation and in the presence of soil, due to the introduction of straight-chain alkylbenzene sulfonate additives in accordance with the invention (runs 8, 9, 10, 11 and 12).- The table furthermore shows that straightchain alkylbenzene sulfonates other than those of the subject invention are ineffective for the purpose of providing good foam persistence (runs3, 4, 5, 6 and 7),.when present in the solutions of washing formulations which contain C polypropylene benzene sulfonate detergents. Run 13 is given to emphasize the deficiency of the tetramer polypropylene derived detergents (runs 1 and 2) in regard to the foam persistence as contrasted with the fpentamer polypropylene derived detergents.

Throughout the aforegiven description of my invention the term commercial C polypropylene benzene sulfonate detergent refers to those polypropylenebenzene sulfonate detergent materials which have been obtained from a tetramer fraction of polypropylene characterized by an average content of about 12 carbon atoms.

It is to be understood that the aforegiven description ficient to enhance the sudsing properties of said polypropylene benzene sulfonate, of a straight-chain alkylbenzene sulfonate having the formula CH8-(CHg)n (oH.).. cHt wherein n is an integer from 5 to 7, n is an integer from 5 to 8, and M is a radical selected from the group consisting of alkali metals and ammonium.

2. A built detergent composition consisting essentially of 10 to 40 parts, by weight, of the composition of claim 1 and to parts, by weight, of inorganic salt detergent builders.

Claims (1)

1. A DETERGENT COMPOSITION CONSISTING ESSENTIALLY OF A WATER-SOLUBLE POLYPROPYLENE BENZENE SULFONATE DETERGENT HAVING AN AVERAGE CARBON CONTENT IN THE POLYPROPYLENE CHAIN OF ABOUT 12 CARBON ATOMS, AND, IN AN AMOUNT SUFFICIENT TO ENHANCE THE SUDSING PROPERTIES OF SAID POLYPROPYLENE BENZENE SULFONATE, OF A STRAIGHT-CHAIN ALKYLBENZENE SULFONATE HAVING THE FORMULA