CA1044983A - Liquid detergent compositions - Google Patents

Abstract

LIQUID DETERGENT COMPOSITIONS

Abstract of the Disclosure Heavy duty liquid detergent compositions are prepared which contain a mixture of particular nonionic surfactants, anionic surfactants and alkanolamines which are especially adapted for good sudsing in the wash and good rinsing under cool water washing conditions.

Description

10449~3 Background of the Invention Field of the Invention This invention relates to concentrated heavy duty liquid compositions for use in cool water fabric laundering. Such compositions contain a nonionic surfactant component, an anionic surfactant component and an alkanol-amine component.
More particularly the invention concerns the use of narrowly defined primary alcohol ethoxylates having the ability to remove soils from fabrics which also provide adequate suds during the wash and easy rinsing after the wash.
In formùlating a liquid detergent composition for consumer use it is important to provide a formulation whose sudsing behavior is similar to the granular .~ , ~L

products customarily used by the consumer i.e., good sudsing during the wash and low suds in the rinse. Nonionics are generally known as low foamers whose foam is persistent at low concentrations even though they do not foam freely at higher concentrations. Under these conditions, the housewife will tend to overuse product to get the desired suds level during the wash and have to contend with a persistent foam during the rinsing operation. These problems may be particularly impor-tant when washing and rinsing at ambient temperature which is the normal practice in some countries, which is desirable for modern fabrics, and which has been suggested as an energy conservation measure.
Prior Art Heavy duty liquid detergent compositions are well known in the art. Usually such compositions (see, for example, U.S. Patents 2,908,651; 2,920,045; 3,272,753; 3,393,154; and Belgian Patents 613,155 and 6Ç5,532) contain a synthetic organic detergent component which is generally anionic, non-ionic, or mixed anionic-nonionic in nature; an inorganic builder salt; and a solvent, usually water and/or alcohol.
These compositions frequently contain a hydrotrope or sol-ubilizing agent to permit the addition of sufficient quantities of surfactant and builder salt to provide a reasonable volume usage/performance ratio. While such liquid detergent composi-tions have been found effective for some types of home laundering, the presence of inorganic builder salts in such compositions may be undesirable from an ecological standpoint in improperly treated sewage.
Several attempts have been made to formulate builder-free~ hydrotrope-free liquid detergent compositions. For example, U.S. Patent 3,528,925 491~3 discloses substantially anhydrous liquid detergent com-positions which consist of an alkyl aryl sulfonic acid, a nonionic surface active agent and an alkanolamine component. U.S. Patent 2,875,153 discloses liquid detergent compositions containing a nonionic surfactant component and a sodium soap component. U.S. Patent 2,543,744 discloses a low-foaming dishwashing composition comprising a nonionic, water-soluble, synthetic detergent and a water-soluble soap in the form of an alkali metal, ammonium or amine salt. All of these detergent compositions are effective for certain types of washing operations, but none of the commercially available compositions of this kind are highly effective both as pretreatment and heavy duty washing agents for cleaning both natural and synthetic fabrics.
U.S. Patent 3,663,445 relates to liquid cleaning and defatting compositions containing a nonionic sur-factant, an alkanolamine-neutralized anionic surfactant and alkanolamine.
Collins, Canadian Patent 992,835 issued July 13, 1976, relates to detergent mixtures comprising a high ratio of nonionic to anionic surfactant and free alkanolamine.
Collins et al, Canadian Patent 1,020,039 issued November 1, 1977, teaches that certain ethylene oxide-based nonionic surfactants can be used at high concentrations in liquid detergent compositions, in combination with alkanol-amines and certain anionic surfactants, and without the need for fatty acid-based stabilizers.

~04~3 U.S. Patents 3,709,838; 3,697,451; 3,55~,916;
3,239,468; 2,947,702; 2,551,634; British Patents 900,000;
842,813; 759,877; and Canadian Patent 615,583 disclose a variety of detergent compositions containing mixed nonionic-anionic surfactants, both with and without alkanolamines.
As can be seen from the foregoing, a substantial effort has been expended in developing low-built and builder-free detergent compositions in liquid form. Yet, there are several problems associàted with the art-disclosed compositions which render them less than optimal for wide-scale use.
First, the prior art is particularly concerned about liquid compositions suitable for fabric cleaning and has not been concerned with formulations that give satisfactory suds during the wash and whose suds are easily broken down during the rinsing operation.
Second, many of the prior art compositions contain phosphorus-based builder materials. Such builders, and compositions containing same, may not be useful in areas of the country having improperly treated sewer~age effluents.
Third, many of the prior art compositions are formulated at too low a ratio of nonionic:anionic surfactant to provide optimal oil~ soil removal from fabrics.
Finally, many of the prior art compositions are formulated to provide satisfactory through-the-w`ash fabric cleaning performance, but do not provide good pre-wash treatment of oily soil iound in collars and .____ _ .. . . . .. . ., . ~ .. .. ..

~L0~4~3 cuffs of fabrics. Most users of liquid laundry detergent compositions expect that superior fabric cleansing can be secured by applying the liquid product directly, at Eull strength, to heavily soiled areas of the fabric prior to laundering. Accordingly, it is desirable t:o provide a liquid detergent having good pre-treatment cleaning benefits as well as good through-the-wash cleaning per-farmance.
It is an object of this invention to provide builder-free, liquid detergent compositions having good pre-wash and through-the-wash fabric cleaning which also suds satisfactorily during the wash and can readily be rinsed away during the rinsing operation.
SUMM~RY OF THE INVENTION
The present invention provides liquid detexgent compositions comprising (a) from about 20~ to about 50%
by weight of a nonionic surfactant produced by the condensation of from about 2 to about 15 moles of ethylene oxide with one mole of a primary alcohol having a straight or branched alkyl chain having 8 to 12 carbon atoms, said nonionic surfactant being further characterized by an HLB
(hydrophilic-lipophilic balance) of from about 8 to abou~
17, preferably 9.0 to 13.5 and especially preferred 9.5 to 12, and a CMC from about 0.006 to about 0.10, preferably 0.008 to 0.05, weight percent, at 25C; (b) an anionic surfactant which is an alkanolamine salt thereof, wherein the anionic portion is selected from the group consisting of alkylbenzene sulfonic acids having from about 9 to about 15 carbon atoms in the alkyl group, alkyl sulfuric acids ha~ing the formula ROSO3H wherein R is an alkyl, straight or branched chain, of about 12 to 16 atoms and mixtures 49~3 thereof, and wherein the alkanolamine is a member selected from the group consisting of monoethanolamine, die~hanol-amine, triethanolamine and mixtures thereof, and wherein the weight ratio of nonionic surfactant to anionic sur-fac~ant is from about 1.8:1 to about 8.0:1 based on the free acid form of the anionic surfactant; and (c) at least 1~ by weight of the composition of free al~anolamine which is a member selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine and mixtures thereof.
_TAILED DESCRIPTION OE' THE INVE NTION
The individual components of t~le instant liquid detergent compositions are described in detail below.
THE NONIONIC SURFACTANT
The compositions o~ this invention contain as an essential ingredient about 20% to about 50%, preferably from about 25% to about 40%, by weig~t of a nonionic sur-factant derived by the condensation of ethylene oxide with a primary alcohol. The general formula for the non ionic surfactant is CnH2n~lO(CH2CH2O)eH-appreciated that the molecule consists of a lipophilic portion derived from the alcohol and a,hydrophilic portion derived from the ethylene oxide. The subscript e refers to the number of moles of ethylene oxide condensed with one mole of alcohol and can be defined as ethoxylate number. The ethoxylate number may refer to the number of moles of ethylene oxide condensed in a single species, i.e., a pure compou~d, but for commercial materials it represents an average.
In the lipophilic portion of -the molecule n is the number of carbons in the alkyl chain of the primary alcohol precursor and is defined as carbon number. For this invention the carbon chain of the aloohol may ~e strai~lt or branched.

Examples of suitable primary straight chain alcohols are the linear primary alcohols obtained from the hydrogenation of vegetable or animal oil fatty acids such as coconut, palm kernel and tallow fatty acids, or by ethylene build-up reactions (Ziegler process) and subsequent hydrolysis of the terminal double bond. Preferred alcohols are n-nonyl, n-decyl and n-undecyl and mixtures thereof. Suitable commercially available ethoxylated alcohols are sold under the trademark "Alfonic" by Conoco Chemicals, Continental Oil Company~
Saddlebrook New Jersey.
E~amples of suitable primary branched chain alcohols are those obtained from the well known O~o process in which linear olefins are reacted with carbon monoxide and hydrogen to produce aldehydes which are then hydrogenated to giv0 alcohols. Both linear and branched chain alcohols are formed.
Commercially available ethoxylates made from these alcohol blends suitable for this invention are marketed by Royal Dutch Shell N.V. under the trademarks "Dobanol" and "Neodol".
The suitable ethoxylated alcohols which enable the formulation of liquid de~ergent compositions for cool water washing having good suds in the wash are shown to contain 2 to 15 moles of ethylene oxide and have an HLB range between 8.0 and 17.0 preferably between 9 and 13.5 and especially preferred between 9.5 and 12. As will be seen in Tables I
and IV and Figure 1 those formulations whose nonionic component has an HLB of 8 to 17 have generally good to intermediate suds in the wash. Those formulations within the preferred HLB range have generally good suds in the wash. The one sample (#9-n=15,e=7) that is within the preferred HLB range but is not satisfactory in suds in the wash is outside the scope of the invention; it does not satisfy the good rinsing ~04~83 requirement which is discussed hereinafter.
The HLB refers to the hydrophilic - lipophilic balance of the nonionic which is a widely accepted measure of the polarity of a surfactant and its relative affinity for aqueous or hydrocarbon media. Developed originally by W. C. Griffin (J.Soc. Cosmetic Chemist Vo:L. I, p. 311, 1949) the concept permits numerical values to be given to surfactant materials, the scale being such that hydrophilicity increases with increase in HLB value. The HLB of the nonionic surfactants herein can be experimentally determined in well-known fashion r or can be calculated in the manner set forth in Decker, "Emulsions Theory and Practice" Reinhold (1965), pp. 233 and 248. For example, the HLB of the nonionic surfactants herein can be simply approximated by the term ~LB = 51[weight percent of ethylene oxide in the molecule].
As indicated by this formula, the HLB will vary, for a given alcohol chain length, with the amount of ethylene oxide present in the molecule. This is shown in more detail in Figure 1 which was constructed by pLotting the calculated HLB'S of alcohol ethoxylates and drawing lines to connect those alcohol ethoxylates having the same HLB.
A second requirement for the nonionic surfactants suitable for this invention is that subsequent to the wash they exhibit good rinsing~ Nonionic surfactants fitting this requirement are shown to have a critical micelle concentration (CMC) of between about 0.006 and about 0.1 weight percent, preferably between 0.008 and 0.05 weight percent in water, provided that the carbon number of the alcohol portion is 8 to 12. The CMC refers to the saturated concentration of nonionic surfactant as singly dispersed species in water.
When additional surfactant is added to such a solution the 1~4D~9~3 additional molecules do not disperse as single species but in dispersing form micelles. This is a well recognized phenomenon in the study of solutions of surface active agents.
Referring now to Tables I and IV and Figure 2, it will be seen that good rinsing was obtained for those com-positions containing an ethoxylated alcohol having a carbon number of 8 to 12 and a CMC between about 0.006 and about 0.1%, preferably 0.008 to 0.05% by weight. The CMC's presented on Figure 2 were derived from the data given in "Nonionic Surfactants" Vol. 1, Marcel Dekker, Inc., N.Y. (1967), M. J. Schick, editor, Table 15.3 pp. 482-486. The CMC data used for Figure 2 were all determined by the surface tension method at 23-25C. The CMC data in Table 15.3 are given in ~-moles per liter but were converted to weight percent in constructing Figure 2 which shows a series of constant CMC
lines as the carbon number and the ethoxylate number of the molecule vary. It will be noted that the sample having n=15,e=3, while having desirable suds in the rinse character-istics, is not within the scope of the invention because this sample does not fall within the HLB limit~ needed for good suds in the wash; i.e., the n=15,e=3 sample has low suds in the rinse because it is a very low sudser in the wash. The n=11,e=12 sample is satisfactory in rinse suds and intermediate in wash sudsing. The sudsing of this sample in~the wash can be made satisfactory without affecting rinse suds by increasing the anionic level in the formula (see Table V).
It should be noted that the CMC requirement applies to the nonionic component of the formulation whether it is a pure component or a mixture of different carbon numbers and/or ethoxylate numbers.
As has been noted, formulations with good sudsing in 9~3 the wash and good rinsing require a nonionic component having a partiaular range of CMC values and carbon numbers. The upper c~a limit serves to define nonionics having a low enough CMC to provide good suds in the wash. It will be appreciated that for good sudsing in the wash, the concentration of the nonionic in the wash solution must exceed the CMC of the nonionic. The upper CMC limit and lower carbon number limit also serve to eliminate those materials which have an appreciable odor intensity which can be a problem in formulating compositions having little odor or in which it is desired to add perfume. The lower CMC and upper carbon number limits define nonionics having good rinsing characteristics; i.e., they exclude nonionics which have persistent suds in the rinse.
It has been discovered that stripping of the nonionic surfactant after ethoxylation, i.e., removing some or all of unethoxylated alcohol, improves detergency. This is described in Collins' concurrently filed copending application, entitled "DETEROENT COMæOSITION", Attorney's Docket Number P&G 2063. Stripping however, is not a factor in achieving 0 the suds characteristics of this invention.
THE ANIONIC SURFACTANT
The anionic component of the instant detergent compositions is a high sudsing alkanolamine salt of an organic anionic acid surfactant. Suitable examp`les include alkylbenzene sulfonic acids, alkyl sulfuric acid, esters of fatty acids sulfonated in the alpha position, alpha olefin sulfonic acids, and mixtures thereof. The alkanolamine anionic salts are prepared by neutralizing the anionic sulfuric or sulfonic organic acid with an alkanolamine selected from the group consisting of monoethanolamine, diethylanolamine, triethanolamine and mixtures thereof.

The triethanolamine salts are preferred herein. The-anionic surfactant salt is employed herein in a quantity sufficient to provide a weight ratio of nonionic surfactant to a~ionic surfactant of from about 1.8:1 to abou~ 8.0:1, preferably at a ratio of 2.5:1 to 5.0:1, based on the free acid form of the anionic surfactant.
For example, the alkanolamine alkylbenzene sulfonate herein preferably consists of a mono-, di- or tri-ethanolamine salt of a straight or branched chain alkylbenzene sulfonic acid in which the alkyl group contains from about 9 to about 15 carbon atoms. Especially preferred surfactants of this type are those in which the alkyl chain i5 linear and averages about 11 to 12 carbon atoms in length. Examples of alkanolamine alkylbenzene sulfonates useful in the instant invention include monoethanolamine decylbenzene sulfonate, diethanolamine undecylbenzene sulfonate, triethanolamine dodecylbenzene sulfonate, monoethanolamine tridecylbenzene sulfonate, triethanolamine tetradecylbenzene sulfonate, and diethanol-amine tetrapropylenebenzene sulfonate, and mixtures thereof.
Examples of cornmercially available alkylbenzene sulfonic acids useful in preparing the alkanolamine sulfonates of the instant invention include Conoco~ SA 515jSA 597 and SA 697, all marketed by the Con-tinental Oil Company, and Calsoft ~ LAS 99~ marketed by the Pilot Chemical Company.
The alkanolamine alkyl sulfate herein consists of a mono-, di- or tri-ethanolamine salt of an alkyl sulfuric acid reaction product having the formula ROS03H wherein R is an alkyl, straight chain or branched chain, of about 8 to 18 carbon atoms. Th`e alkyl sulfuric acid reaction product is made by reacting sulfuric acid with a monohyclric alcohol having about 8 to 18 carbon atoms. Preferably R
has 12 to 16 carbon atoms.
Another anionic detergent useful herein is the ethanolamine salt o an alpha sulfonated fatty acid.
These materials have the formula H O

Ri -- C - C -- O -- R2 wherein X is selected from the group consisting of .nonG-ethanolamine, diethanolamine, triethanolamine and mixtures thereof; Rl is an alkyl chain of from about 6 to about 20 carbon atoms ~forming with the two carbon atoms a fatty acid group); and R2 is an alkyl chain, the sum of the carbon atoms in Rl and R2 being from about 13 to about 23 carbon atoms. Specific examples of this class of compounds include esters wherein R2 is methyl, ethyl, propyl, butyl, hexyl and octyl groups and the fatty acid group (Rl plus the two carbon atoms in the structure above) is lauric, myristic, palmitic, stearic acids and mixtures thereof.

Yet another anionic detergent useful herein consists of a mono-, di- or tri-ethanolamine salt of 10~49~3 alpha olefin sulfonic acids and mixtures thereof. The sulfonation of alpha olefins and the compositions resulting therefrom are described more fully in U.S. Patent 3,332,880 of Phillip F. Pflaumer and Adriaan Kessler, issued July Z5, 1967, titled DETERGENT COMPOSITION.
The Alkanolamine A third essential component of the liquid detergent composition of the present invention is the alkanolamine compound. The alkanolamine useful herein is selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine, and mixtures thereof.
Mixtures of these three alkanolamine compounds are produced by the reaction of ethylene oxide with ammonia. The pu e compounds can be separated from this mixture by stanclard distillation procedures.
The alkanolamine component of the present invention serves two purposes. As will be discussed more fully hereinafter, in the preferred method for preparing the instant compositions the alkanolamine Z0 neutralizes the free acid form of the anionic surfactant to provide the corresponding alkanolamine salt which is an essential component of the instant detergent compositions, In addition, the excess alkanolamine beyond that necessary to form the anionic surfactant salt contributes to detergency performance and serves as a buffering agent which maintains wash .~ .

4t9~3 water pH of the instant compositions within the range from about 7 to about 9. It is essential that the compositions of this invention contain at least 1~ by weight of the total composition of free alkanolamine, i.e., an excess over that needed to neutralize the alkylbenzene sulfonic acid anionic surfactant.
Stable liquid ~etergent compositions containing nonionic, anionic and alkanolamine components can be for-mulated by preparing each component separately and thoroughly mixing them together in any order. In a preferred method for preparing the instant compositions, the anionic and alkanol-amine components are formulated simultaneously by over-neutralizing the alkylbenzene sulfonic acid with alkanolamine.
This method forms the requisite alkanolamine alkyl benzene sulfonate and provides the free alkanolamine component of the instant composition. Preferably, the compositions contain from about 2.0% to about 15.0~ by weight of free alkanolamine, most preferably triethanolamine.
Optional Components Although the liquid detergent compositions of the instant invention need only contain the above-described three components (i.e., thick, anhydrous compositions), highly preferred compositions herein contain, in addition to the three active components, a solvent selected from`the group consisting of water and water-alcohol mixtures. Such solvents can be employed to the extent of from about 1% to 45% by weight of the total detergent composition. In preferred compositions the solvent comprises from about 25% to 45% by weight of the total composition. Use of such solvents in the compositions herein has several advantages. First, the physical stability of the detergent compositions can be 9~3 improved by dilution with such solven-ts in that clear points Gan thereby be lowered. The diluted compositions do not cloud at the low temperatures which are commonly encountered during shipping or storing of commercially marketed detergent compositions.
Secondly, addition of solvents, especially water-alcohol mixtures, serves to regulate the gelling tendency which liquid detergent compositions of the instant type exhibit upon dilution with water.
When an alcohol-water mixture is employed as a solvent, the weight ratio of water to alcohol preferably is main-tained above about 3:1, more preferably from about 4:1 to about 7:1. ~liyh alcohol (particularly e-thanol) concentrations in the water-alcohol mixtures used in the instant invention are preferably avoided because of flammability problems which may arise at such higher alcohol levels.
Any alcohol containing from 1 to about 5 carbon atoms can be employed in the water-alcoho:L diluent used to prepare the instant detergent compositions. Examples of operable alcohols include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, and pentanol; ethanol is highly preferred for general use.
A second optional component which can be added to the detergent compositions of the instant invention is an electrolyte salt. As pointed out in U.S. Patents 2,530,173 and 3,440,171, electrolyte salts lessen the gel formation which tends to occur with alkanolamine-neutralized surfactants.
Such electrolytes, when used herein in combination with a water-alcohol solvent at a weight percent of the total com-position of from about 0.2% to 5% of said electrolyte salt, 491~3 substantially eliminate gelation of the anionic surfactant without the need for excessively high alcohol levels.
Operable electrolyte salts include the alkali metal chlorides, sulfates and carbonates, and the salts formed from the reaction of alkanolamines with inorganic acids, e.g.
HCl, H2SO4, and organic acids such as formic, acetic, propionic, butyric and citric acid. Specific examples of such salts include sodium chloride, potassium chloride, sodium carbonate, potassium carbonate, potassium sulfate, sodium sulfate, tri-ethanolamine sulfate, triethanolamine citrate, triethanolamineacetate, triethanolamine formate, monoethanolamine proprionate and diethanolamine butyrate. Of all the possible electrolyte salts useful to prevent gelation of the compositions herein, potassium chloride is highly effective and pre~erred. Potassium chloride is preferably added to the instant compositions to the extent of from about 1~ to 3% by weigh-t to provide its anti-gelling effects.
As noted, the employment of a solvent and electrolyte serves to control and regulate gel formati~n in the instant liquid detergent compositions. If, however, gel formation is desired, it is possible to select particular concentrations of a water solvent which yield gelled compositions in the absence of alcohol and electrolyte salt. Thus, compositions containing the three active components in the above-specified concentrations and a water solvent comprising from about 15%
to 35~ by weight will be thick or gelled compositions, provided no alcohol or electrolyte is present.
Other optional, non-essential, non-interfering components can be added to the instant compositions to provide improved performance or aesthetic appeal. Preferred compositions of the invention are those to which a color L9~33 stabilizing agent such as citric acid has been added. These compositions exhibit surprising stability against the tendency of such compositions to develop a reddening upon storage. In addition, the presence of citric acid in the compositions of the invention has a beneficial effect from the standpoint of preventing the development of the stains observed on the outer surfaces of plastic bottles and occasioned by spillage, seepage or handling of bottles with hands previously contacted with the compositions of the invention. As with the anionic surfactant acids, the citric acid forms alkanolamine citrate when added to the instant compositions containing excess alkanolamine. For convenience however, this alkanolam:ine citrate concentration ln the compositions is expressed as a weight percentage of the free acid form of the citrate, i.e., citric acid, added to the compositions. An amount of citric acid of up to about 1~ by weight of composition is generally added to obtain these color benefits. A highly preferred range for the added citric acid is from about 0.05% to about 0.30~ by weight of composition. Of course, the com-positions must still be formulated to maintain the minimumof about 1% (wt.) of free alkanolamine.
Suds suppressing agents can be present in the instant compositions in minor proportions to provide lower foaming products. While the compositions herein inhere~tly provide adequate suds levels during the wash and good rinsing after the wash, some users desire lower sudsing products for the washing cycle which also improves rinsing. Accordingly, the compositions herein can optionally contain from about 0.5% to about 3% by weight of fatty acids as suds suppressing agents.
Useful fatty acids for this purpose consist of those fatty acids containing from about 8 to about 24 carbon atoms and ' 9~3 preferably from about 10 to about 20 carbon atoms. Suitable fatty acids can be obtained from natural sources such as, for example, plant or animal esters (e.g., palm oil, coconut oil, babassu oil, soybean oil, safflower oil, tall oil, castor oil, tallow, whale and fish oils, lord, grease and mixtures thereof).
The fatty acids also can be synthetically prepared (e.g., by the oxidation of petroleum or by hydrogenation of carbon monoxide via the Fischer-Tropsch process). Examples of preferred fatty acids for use as suds suppressing agents are those derived from coconut oil, olein and tallow. It should be understood that the fatty acid suds suppressor, while added as the acid in making the composition, will exist as the alkanolamine salt of the fatty acid in the composition because of the requirement that there be at least 1~ by weiyht oE free alkanolamine in the composition.
Other optional components include brightne~s, bluing agents, fluorescers, enzymes, bleaching agents, anti-microbial agents, corrosion inhibitors and coloring agents.
Such components preferably comprise no more than about 3~ by weight of the total composition.
Utilization of nonionic surfactant to anionic surfactant (free acid basis) ratios of from about 1.8:1 to about 8.0:1 in combination with utilization of excess free alkanolamine is important to formation of detergent compositions having good cleaning performance and good stability character-istics of the instant invention. Formation of mixed surfactant micelles, which results from employment of the particular nonionic-anionic surfactant ratio of the instant invention, provides good detergency performance which is insensitive to water hardness.
Employment of alkanolamine salts and excess alkanolamine also contributes to the ef~ec-tiveness of the instant detergent compositions. For example, these com-positions containing the alkanolamine counterion in combination with excess free alkanolamine are superior in cleaning polyester/cotton than corresponding com-positions containing the more conventional sodium or potassium salts of the anionic surfactant acids and no free alkanolamine. Of the alkanolamines, triethanolamine is preferred herein from the sta~dpoint of availability and cleaning efficiency.
The compositions of the instant invention are also designed to provide good cleaning benefits when used in either of the two modes commonly employed with liquid detergent compositions. First, the compositions herein can be used as pre-treatment agents which are applied in concentrated form directly onto fabric stains prior to fabric washing. Second, the instant compositions are also useful as detergents for conventional through-the-wash fabric laundering operations. Good stain removal and soil removal are attained when the instant compositions are dissolved in an aqueous washing solution at a concentration of at least about 0.10% by weight ~approximately 30 grams per 30 liters of wash water.) For through-the-wash fabric laundering, a concen~tration of the instant compositions in the range of from 0.08%
to about 0.20% by weight of the laundering liquor is preferred. Of course, this can be adjusted, depending on the soil load and the desires of the user.
With regard to pre-treatment efficacy, the instant compositions containing the herein specified 3 ~44~B3 componen-ts and component ratios provide oily stain removal from polyester or polyester/cotton fabrics which is superior to similar pre treatment performance attained by utilization of conventional built anionic detergent compositions and which is, in fact, com-- parable in oily stain removal with that attained with pure nonionic surfactan-ts which are known to be par-ticularly useful in such pre-treatment stain removal.
Through-the-wash detergency performance of the instant compositions is, in fact, comparable with that attained with conventional built granular anionic detergent compositions.
The following examples illustrate the liquid detergent compositions of the instant invention.
EXAMPLES
Laundry Procedure Several formulations were evaluated for sudsing characteristics during washing and after the rinsing operation. The procedure consisted of filling the wash tub with water, adding the product, agitating for 1 minute to dissolve the product and then adding a load of naturally soiled clothes. After the clothes were washed they were removed from the wash tub and extracted to remove some of the washing solution~.
The washing solution in the tub was drained off, the tub rinsed and then filled with water. The extracted clothes were then added back to the wash tub and rinsed with agitation. During the rinse additional water flowed into the tub and the overflow ran into a pipe leading to the drain. Sudsing observations .

~o~
were made during the washing process, during the rinsing operation and when the rinsing time allowed was completed.
Washing machine - top loading semiautomatic;
impeller type with reversing agitation; operated manually during the rinse; has built in extractor adjacent to the wash tub.
10 Model - National NA6050 Manufacturer - MATSUSHITA DENKI SANGYO KK
Washing Machine Division Osaka, Japan Agitation - Normal spee~, reversing Wash fill level - 30 liters Water temperature - 21C (70F) Water hardness - 0.79 grains/liter as CaCO

(3 gr/U.S. gal.) Product usage ~ 35 grams 20 Fabric load - 1.2 kilograms of naturally soiled clothes Washing time - 10 minutes Extraction - 2 minute spin Rinse - 34 liters of water, as abovè, 10 minutes rinsing time with normal speed reversing agitation;
during rinsing additional water ~ flows into the tub and the over-; flow goes to the drain through an overflow pipe.

9~)4~ 3 The sudsing characteristics of the t~st products were judged by the following scale:
During t wash (1) Suds cover may be present but is less than 1 cm. in height.

(2) Suds cover is present but the suds height falls in the 1 to 3 cm. range.

(3) Sudsing during the wash was similar to Japanese granular products on the cu~rent retail market. "Typical"
suds caver is about 3 to 6 cm.
Suds _ the rinse (1) No suds in the rinse water or, if present, collapse readily to yield a clear solution with only traces of very finely divided bubbles.
(2) Residual foam is present at low level or that slight turbidity persisted after agitation st~pped.
This grade defines a rinsing character that is slightly poorer than desired.
(3) Substantial or very persistent suds observed in the rinse.

: Using the procedure outlined above several-liquid compositions were tested for their suds characteristics.
The results observed are shown in the following table:

' ' .

.

. ~ 983 . ,~: ~ .. .
. ~ ~' ' - .

. ~ . ', . I
., ~, .

h X X X X X X X X ~ ~ ~1 ~ ~ . ..
n c~
.
. . '' . ~ ~ .

ol u~ D r-C~ o o ~1 æ a) , ~ ~ O ''' '' '' '' I '~ '' O O
Q ~ 2 ;
. u I
. ., , ', . .
. . Ql ' x I J ~ ~ ~ ~ ~ ~ O~3 .
: ' .

Explanation of Table I
Description of Column Headings A . Identification of alcohol lipophile:
(a) A mixture of linear primary alcohols (5~ C8, 95% C10) ethoxylated with an average of 3.0 moles ethylene oxide per mole of alcohol, which was stripped under vacuum (thereby removing most of the residual unethoxylated alcohol, resulting in an average ethoxylate number of 4.1).
(b) Alcohol derived from coconut oil.
(c) A mixture of linear primary alcohols (5% C8, 95% C10) ethoxylated with an average o~ 9.0 moles ethylene oxide per mole of alcohol.
(d) Fatty alcohol derived from natural sources.
te) "Oxo" alcohol.
B,C. Carbon number is defined as the number of carbon atoms in the alcohol lipophile. Colloidal properties such as micellization, foaming and detergency are well-known to be dominated, in mixtures, by components having low critical micelle concentration CMC. As shown on Figure 1, CMC is primarily a function of carbon number among the lipophiles of this invention. Hence the "dominant" carbon number is selected to be distinctly above the average carbon number ~or alllipophiles.
~. Ethoxylate number is defined as the average number of moles of ethylene oxide condensed onto each mole of alcohol lipophile.

E. Symbol "x" indicates the following liquid detergent composition:
Composition Wt.
Nonionic (as indicated below) 33.0 Linear alkyl benzenesulfonic acid 11.0 (HLAS) (added as acid form but neutralized with TEA during making).
Triethanolàmine 11.0 Ethanol 5.0 KCL 2.5 Citric Acid 0.25 Brightener 0.~
Water (inc. optional color/perfume) Balance 100.0 Symbol "y" indicates a similar composition where the HLAS usage has ~een increased from 11.0% to 16.5%, replacing water, and all other usages remain the same. Symbol "~"
indicates a composition to which 2~ oleic acid has been added, replacing water.
F,G. Sudsing is graded on a 3-point scale: "3"
signifies high suds; "2" signifies an inter-mediate suds level; and "1" signifies low suds. Sudsing in the wash and in the rinse were graded on separate and relative scales.
It will be noted that "high" sudsing with references to the rinse indicates a vastly lower absolute level of suds than "high"
sudsing in the wash. Desirable properties are "high" suds in the wash and "low" suds in the rinse.

3t83 Examples 1, 10 and 11 are within the scope-of the invention.
To help visualize the nonionics of interest, which unexpectedly provide good sudsing in the wash and good rinsing after the wash, Examples 1-11 are plot-ted (the circled numbers) in Figures 1 and 2.
Using the above procedure, additional heavy duty liquid detergent composi~ions containing ethoxylated alcohols are tested. Table II summarizes the ethoxylates that are used and the results that are obtained.

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that denotes the use of Ziegler fatty alcohol as the lipophile.
Examples 12-16 illustrate the good sudsing and good rinsing results that are obtained when the ethoxylate is within the preferred HLB range of 9.0 to 13.5 and the preferred CMC range of 0.008 to 0.05.
Examples 17-23 illustrate the results that are obtained when the ethoxylate is within the broad range of 8.0 to 15.0 for HLB and 0.006 to 0.10 for CMC.
Formulations are prepared with the nonionic composition used in Example 1 to test the formula variations.
Table III summarizes the formulations that are prepared~

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9~3 For each of the above compositions, substantially similar sudsing results in both the wash and the rinse are obtained as for the compositions of Example 1. Detergency for laundry pre-treatment is good and detergency through-the-wash is in each case satisfactory.
Sudsing_Evaluation Using Artificial Soil Several formulations were evaluated for sudsing characteristics during the wash and rinsing after the wash as hereinbefore described except for the following differences:
Product usage: 40 grams.
Fabric Load: 8 clean T-shirts (1.0 Kg.) Artificial Soil Load: (added immediately after the Eabric load) (a) Three 15x28 cm. muslin swatches containing a total of 5.0 grams of organic soil as hereinafter described and (b) 10 grams of "inorganic" soil as hereinafter described.
The artificially soiled swatches were prepared by dissolving 5.0 grams of organic soil in 20 ml. of carbon tetrachloride, allowing the solution to be absorbed by three pieces of 15x28 cm. cotton muslin fabric and drying and aging the swatches overnight in a fume hood. The organic soil consisted of 1.0 grams of lactic acid and 4.0 grams of synthetic sebum having the following composition:

9~3 - Palmitic acid 10~0%
Stearic acid 5.0 Oleic acid 15.0 Coconut oil 15~0 Olive oil 20.0 Squaline 5.0 Paraffin 10.0 Cholesterol 5.0 Spermaceti 15.0 100.O
The "inorganic" soil consisted of a mix-ture of 5.0 grams of bentonite clay, 4.0 grams of salt and 1.0 gramr, of urea.
The sudsing characteristics of the compositions tested using artificial soil were made using the washing and rinsing procedure hereinbefore described. The formulations tested and the results observed are given in Table IV.

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Examples 31, 32, 33, and 35 are within the scope of the invention. It will be noted that Example 33 was rated as slightly less than satisfactory in sudsing during the wash. The sudsing in the wash of Example 33 can be improved without effecting rinse 5 Suds by increasing the anionic level (see Table V).
To help visualize the nonionics of interest, which unexpectedly provide good sudsing in the wash and good rinsing after the wash, Examples 30-35 (numbers in square boxes) are plotted in Figures 1 and 2.
Additional compositions are tested for sudsing character-istics with artificial soil using the washing and rinsing procedure hereinbefore described. TABLE V summarizes the compositions that are tested and the results that are obtained.

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Example 36, which is identical to Example 33 (Table IV), is observed to have marginal to satisfactory sudsing during the wash and satisfactory suds in the rinse. Example 37 is similar to Example 36 except that the HL~S content is higher (16.5~ vs 11%). The effect of increasing the HLAS content in the composition is seen to improve the sudsing characteristics during the wash and to have no effect on the rinse characteristics following the wash.
Examples 36 through 39 are within 1:he scope of the in-vention.

WHAT IS CLAIMED IS:

~ 36

Claims (15)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
l. A liquid detergent composition, consisting essentially of:
(a) from about 20% to about 50 % by weight of a.
nonionic surfactant which is an ethoxylated alcohol having an average mole ratio of ethylene oxide to alcohol of from about 2:1 to 15:1, wherein the alcohol is a straight or branched, primary alcohol having 8 to 12 carbon atoms in the alkyl chain, said nonionic surfactant being further characterized by an HLB of from about 8.0 to about 17.0 and a CMC from about 0.006 to about 0.10 weight percent at 25°C;
(b) an anionic surfactant which is an alkanolamine salt thereof, wherein the anionic portion is selected from the group consisting of alkyl-benzene sulfonic acids having from about 9 to about 15 carbon atoms in the alkyl group, alkyl sulfuric acids having the formula ROSO3H wherein R is an alkyl, straight or branched chain, of about 12 to 16 atoms and mixtures thereof, and wherein the alkanolamine is a member selected from the group consisting of monoethanolamine, di-ethanolamine, triethanolamine and mixtures thereof, and wherein the weight ratio of nonionic surfactant to anionic surfactant is from about

1.8:1 to about 8.0:1 based on the free acid form of the anionic surfactant; and (c) at least 1% by weight of the composition of free alkanolamine which is a member selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine and mixtures thereof.

2. A composition according to claim 1 wherein the CMC of the nonionic surfactant is from about 0.008 to about 0.05.

3. A composition according to claim 2 wherein the HLB of the nonionic surfactant is from about 9.5 to about 12.

4. A composition according to claim 1 wherein the anionic surfactant is alkylbenzene sulfonic acid wherein the alkyl chain is linear and averages about 11 to 12 carbon atoms in length.

5. A composition according to claim 4 wherein the nonionic surfactant has a CMC of from about 0.006 to 0.05 and an HLB from about 9.5 to about 12.

6. A composition according to claim 1 wherein the alkanolamine salt of the anionic surfactant is the tri-ethanolamine salt.

7. A composition according to claim 1 wherein the free alkanolamine is triethanolamine and is present in the composition at a concentration of from about 2.0 to about 15% by weight.

8. A composition according to claim 1 where in the nonionic:anionic surfactant weight ratio is in the range of from 2.5:1 to 5.0:1.

9. A composition according to claim 1 wherein the ninionic surfactant is characterized by a CMC of from .008 to 0.05 and an HLB from 9.5 to 12; the anionic sur-factant is a triethanolamine salt of an alkylbenzene sulfonic acid having an average of 11 to 12 carbon atoms in the alkyl group; and the free alkanolamine is triethanol-amine.

10. A composition according to claim 1 which additionally contains from about 1% to about 45% by weight of a solvent selected from the group consisting of water, methanol, ethanol, propanol, isopropanol, butanol, iso-butanol, pentanol and mixtures thereof.

11. A composition according to claim 10 wherein the alcohol is ethanol.

12. A composition according to claim 10 which additionally contains from about 0.2% to about 5% by weight of potassium chloride.

13. A composition according to claim 10 which additionally contains from about 0.05% to about 1% by weight of citric acid, based on the free acid form.

14. A composition according to claim 10 which additionally contains from about 1% to about 3% by weight of oleic acid, based on the free acid form.

15. A composition according to claim 9 wherein the nonionic:anionic surfactant weight ratio is in the range of from 2.5:1 to 5.0:1 and wherein the triethanolamine is present in the composition at a concentration of from about 2% to about 15% by weight.