Title:
Liquid detergent compositions
United States Patent 3869399
Abstract:
Concentrated heavy duty liquid detergent compositions containing a mixture of a nonionic surfactant, an anionic surfactant and ethanolamine and being especially adapted to stain and soil removal from fabrics, either applied directly to such fabrics before washing or employed as detergent compositions for conventional fabric laundering.
US Patent References:
Laundering composition and process
Hall - July 1937 - 2086867
Liquid soap composition
Price - May 1951 - 2551634
Stable liquid shampoos
Henkin - November 1956 - 2770599
Liquid detergent compositions
Coskie - August 1960 - 2947702
Hard surface cleaning compositions
Herrick - March 1966 - 3239468
Laundering composition and process
Hall - July 1937 - 2086867
Liquid soap composition
Price - May 1951 - 2551634
Stable liquid shampoos
Henkin - November 1956 - 2770599
Liquid detergent compositions
Coskie - August 1960 - 2947702
Hard surface cleaning compositions
Herrick - March 1966 - 3239468
Application Number:
05/222363
Publication Date:
03/04/1975
Filing Date:
01/31/1972
View Patent Images:
Export Citation:
Assignee:
The Procter & Gamble Company (Cincinnati, OH)
Primary Class:
Other Classes:
510/341, 510/425, 510/342, 510/343, 510/284, 510/325
International Classes:
C11D3/30; C11D9/02; C11D9/30; C11D10/04; C11D17/00; C11D1/02; C11D1/22; C11D1/66; C11D1/72; C11D3/26; C11D9/00; C11D9/04; C11D10/00; C11D17/08; C11D9/46; C11D1/83
Field of Search:
252/110,111,112,117,118,545,539,540,548,115,558,559
US Patent References:
Other References:
Kastra, Defensive Publication of S.N. 182,863, filed 9/22/71, published in 903 O.G 6, on 10/3/72, Defensive Publication No. T903, 009. .
Kastra, Defensive Publication of S.N. 182,883, filed 9/22/71, published in 903 O.G. 6, on 10/3/72, Defensive Publication No. T903,010. .
"Emulsions and Detergents" booklet published by Union Carbide, 1961, pages 7-9..
Primary Examiner:
Weinblatt, Mayer
Assistant Examiner:
Albrecht, Dennis L.
Attorney, Agent or Firm:
Allen, Yetter Schaeffer G. W. J. J. J. D.
Claims:
What is claimed is
1. A liquid fabric cleaning detergent composition consisting essentially of
2. A composition in accordance with claim 1 wherein
3. The composition of claim 2 which contains triethanolamine citrate in a concentration based upon the citric acid form of from about 0.05 to about 0.10 percent by weight of the composition.
1. A liquid fabric cleaning detergent composition consisting essentially of
2. A composition in accordance with claim 1 wherein
3. The composition of claim 2 which contains triethanolamine citrate in a concentration based upon the citric acid form of from about 0.05 to about 0.10 percent by weight of the composition.
Description:
BACKGROUND OF THE INVENTION
The present invention relates to concentrated heavy duty liquid detergent compositions. As used herein, the term "liquid" encompasses semi-liquid or gel compositions as well as more conventional freely-flowing formulations. Such compositions contain a nonionic surfactant component, a mixture of anionic surfactants and an ethanolamine component.
Heavy duty liquid detergent compositions are wellknown in the art. Usually such compositions (see, for example, U.S. Pat. Nos. 2,908,651; 2,920,045; 3,272,753, 3,393,154; and Belgian Pat. Nos. 613,165 and 665,532) contain a synthetic organic detergent component which is generally anionic, nonionic, 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 solubilizing 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 compositions 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 if such compositions are employed on a broad scale.
Several attempts have been made to formulate builderfree, hydrotrope-free liquid detergent compositions. For example, U.S. Pat. No. 3,528,925 discloses substantially anhydrous liquid detergent compositions which consist of alkyl aryl sulfonic acid, a nonionic surface active agent and an alkanolamine component. U.S. Pat. No. 2,875,153 discloses liquid detergent compositions containing a nonionic surfactant component and a sodium soap component. U.S. Pat. No. 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 as pre-treatment and heavy duty washing agents for cleaning both natural and synthetic fabrics.
Accordingly, it is an object of the present invention to provide concentrated heavy duty liquid detergent compositions which are highly effective on all types of fabrics both as stain pre-treatment agents and as laundry washing agents.
It is a further object of the instant invention to provide liquid detergent compositions which are free of inorganic builders and conventional hydrotropes.
It is a further object of the instant invention to formulate such heavy duty liquid detergent compositions which are chemically and physically stable and which are relatively non-toxic and non-irritating.
It has been discovered that by employing particular nonionic and anionic surfactants in combination with certain ethanolamine compounds in very specific ratios of such components, these above-described objectives can be attained, and liquid detergent compositions can be formulated which are unexpectedly superior to liquid detergent compositions presently known to the prior art.
SUMMARY OF THE INVENTION
The present invention provides liquid detergent compositions consisting essentially of (a) from about 30 to about 60 percent by weight of a nonionic surfactant produced by the condensation of alkylene oxide with an organic hydrophobic compound; (b) an anionic surfactant mixture (as hereinafter defined) in an amount sufficient to provide a weight ratio of nonionic surfactant to anionic surfactant mixture within the range of from about 2.5:1 to about 3.5:1 based on the free acid form of the anionic surfactants; and (c) an ethanolamine in an amount sufficient to provide at least 1 percent by weight of the composition of ethanolamine.
The anionic surfactant mixture consists of two components: (1) a mono-, di- or tri-ethanolamine alkyl benzene sulfonate having from about 9 to about 15 carbon atoms in the alkyl chain; and (2) a mono-, di- or tri-ethanolamine soap containing from about 8 to about 24 carbon atoms in the fatty acid moiety thereof. These two components of the anionic surfactant mixture are present in quantities sufficient to provide a weight ratio of the acid form of the sulfonate to the acid form of the soap of from about 20:1 to about 1:1.
DESCRIPTION OF THE INVENTION
The components of the instant detergent compositions are discussed in detail as follows:
THE NONIONIC SURFACTANT
From about 30 to about 60 percent by weight of the liquid detergent compositions of the present invention consists of a nonionic surfactant derived by the condensation of an alkylene oxide (hydrophilic in nature) with an organic hydrophobic compound, which is usually aliphatic or alkyl aromatic in nature. The length of the hydrophilic or polyoxyalkylene moiety which is condensed with any particular hydrophobic compound can be readily adjusted to yield a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements. Examples of suitable nonionic surfactants are:
1. The polyethylene oxide condensates of alkyl phenols. These compounds include the condensation products of alkyl phenols having an alkyl group containing from about 6 to 12 carbon atoms in either a straight chain or branched chain configuration, with ethylene oxide, the said ethylene oxide being present in amounts equal to 5 to 25 moles of ethylene oxide per mole of alkyl phenol. The alkyl substituent in such compounds may be derived, for example, from polymerized propylene, diisobutylene, octene, or nonene. Examples of compounds of this type include nonyl phenol condensed with about 9.5 moles of ethylene oxide per mole of nonyl phenol, dodecyl phenol condensed with about 12 moles of ethylene oxide per mole of phenol, di- nonyl phenol condensed with about 15 moles of ethylene oxide per mole of phenol, di-isooctylphenol condensed with about 15 moles of ethylene oxide per mole of phenol. Commercially available nonionic surfactants of this type include Igepal CO-630 marketed by the GAF Corp.; and Triton X-45, X-114, X-100 and X-102, all marketed by the Rohm and Haas Co.
2. The condensation products of aliphatic alcohols with ethylene oxide. The alkyl chain of the aliphatic alcohol may either be straight or branched and generally contains from about 8 to about 22 carbon atoms. Examples of such ethoxylated alcohols include the condensation product of about 6 moles of ethylene oxide with 1 mole of tridecanol, myristyl alcohol condensed with about 10 moles of ethylene oxide per mole of myristyl alcohol, the condensation product of ethylene oxide with coconut fatty alcohol wherein the coconut alcohol is a mixture of fatty alcohols with alkyl chains varying from 10 to 14 carbon atoms in length and wherein the condensate contains about 6 moles of ethylene oxide per mole of alcohol, and the condensation product of about 9 moles of ethylene oxide with the above-described coconut alcohol. Examples of commercially available nonionic surfactants of this type include Tergitol 15-S-9 marketed by the Union Carbide Corp., Neodol 23-6.5 marketed by the Shell Chemical Co. and Kyro EOB marketed by the Procter & Gamble Co.
3. The condensation products of ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol. The hydrophobic portion of these compounds has a molecular weight of from about 1,500 to 1,800 and of course exhibits water insolubility. The addition of polyoxyethylene moieties to this hydrophobic portion tends to increase the water-solubility of the molecule as a whole, and the liquid character of the product is retained up to the point where the polyoxyethylene content is about 50 percent of the total weight of the condensation product. Examples of compounds of this type include certain of the commercially available Pluronic surfactants marketed by the Wyandotte Chemicals Corp.
4. The condensation products of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylene diamine. The hydrophobic base of these products consists of the reaction product of ethylene diamine and excess propylene oxide, said base having a molecular weight of from about 2,500 to about 3,000. This base is condensed with ethylene oxide to the extent that the condensation product contains from about 40 to about 80 percent by weight of polyoxyethylene and has a molecular weight of from about 5,000 to about 11,000. Examples of this type of nonionic surfactant include certain of the commercially available Tetronic compounds marketed by the Wyandotte Chemicals Corp.
For use in the detergent compositions of the instant invention, it is preferred that the particular nonionic surfactant employed have a hydrophilic-lipophilic balance (HLB) of from about 8 to about 15. A highly preferred nonionic surfactant within this range is the condensation product of 6 moles of ethylene oxide with coconut fatty alcohol. (HLB = 12)
The presence of the nonionic surfactant in the instant liquid detergent compositions in the essential specified concentration provides the necessary oily stain removal in both pre-treatment application and wash water utilization of the instant invention. Such nonionic surfactant also contributes to the physical stability of the liquid detergent compositions.
THE ANIONIC SURFACTANT MIXTURE
The anionic component of the instant detergent compositions consists of a mixture of an ethanolamine salt of an alkylbenzene sulfonic acid (an ethanolamine alkylbenzene sulfonate) and an ethanolamine salt of a fatty acid (hereinafter referred to as an ethanolamine soap). Both of these salts are prepared by neutralizing the corresponding anionic acids with an ethanolamine selected from the group consisting of monoethanolamine, diethanolamine and triethanolamine. The mixture of anionic surfactant salts is employed herein in a quantity sufficient to provide a weight ratio of nonionic surfactant to anionic surfactant mixture of from about 2.5:1 to about 3.5:1, based on the free acid form of the anionic surfactants.
The non-soap component of the anionic surfactant mixture consists of a mono-, di- or tri-ethanolamine salt of a straight or branched chain alkyl benzene sulfonic acid in which the alkyl group contains from about 9 to about 15 carbon atoms. Preferred surfactants of this type are those in which the alkyl chain is linear and averages about 12 carbon atoms in length. Examples of ethanolamine alkyl benzene sulfonates useful in the instant invention include monoethanolamine decyl benzene sulfonate, diethanolamine undecyl benzene sulfonate, triethanolamine dodecyl benzene sulfonate, monoethanolamine tridecyl benzene sulfonate, triethanolamine tetradecyl benzene sulfonate and diethanolamine tetrapropylene benzene sulfonate. Examples of commercially available alkyl benzene sulfonic acids useful in preparing the ethanolamine sulfonates of the instant invention include Conoco SA 515, SA 597, and SA 697 all marketed by the Continental Oil Co. and Calsoft LAS 99 marketed by the Pilot Chemical Co.
The soap component of the anionic surfactant mixture consists of mono-, di- and triethanolamine soaps of fatty acids containing from about 8 to about 24 carbon atoms and 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, grease, lard, 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 suitable soaps for use in the instant invention include monoethanolamine caproate, diethanolamine laurate, triethanolamine myristate, triethanolamine palmitate, monoethanolamine stearate and diethanolamine palmitoleate. Preferred soaps include the mono-, di- and triethanolamine soaps of mixtures of fatty acids derived from coconut oil and tallow. A highly preferred soap for use in the instant invention is triethanolamine oleate. Examples of commercially available fatty acids for use in preparing the ethanolamine soaps of the instant invention include C-105, C-108, C-110, T-10, T-11 and OL-910 all marketed by The Proctor & Gamble Co., and Hyfac, a hydrogenated fish oil fatty acid marketed by Emery Industries, Inc.
Within the anionic surfactant mixture, the two components thereof are present in quantities sufficient to provide a weight ratio of the acid form of the sulfonate (an alkyl benzene sulfonic acid) to the acid form of the soap (a fatty acid) of from about 20:1 to about 1:1, preferably from about 4:1 to 8:1. It has been found that anionic mixture component weight ratios within this range provide an unexpectedly high degree of soil and stain removal and at the same time maintain excellent suds control during both wash and rinse.
As noted, the anionic surfactant mixture as a whole must be present in the instant liquid detergent compositions to such an extent that the weight ratio of nonionic surfactant to anionic surfactant (calculated on a free anionic acid basis) is approximately 3:1, i.e., from about 2.5:1 to about 3.5:1. The reasons for this essential weight ratio limitation will be discussed more fully below.
THE ETHANOLAMINE
A third essential component of the liquid detergent composition of the present invention is the ethanolamine compound. The ethanolamine useful herein is selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine and mixtures thereof. Mixtures of these three ethanolamine compounds are produced by the reaction of ethylene oxide with ammonia. The pure compounds can be separated from this mixture by standard distillation procedures.
The ethanolamine 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 ethanolamine neutralizes the free acid form of the anionic surfactant mixture to provide the corresponding ethanolamine salts which are essential components of the instant detergent compositions. In addition, the excess ethanolamine beyond that necessary to form the anionic surfactant salts in accordance with the invention contributes to detergency performance and serves as a buffering agent which maintains wash 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 percent by weight of the total composition of free ethanolamine.
The above-described compositions containing nonionic, anionic and ethanolamine components can be formulated 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 ethanolamine components are formulated simultaneously by over-neutralizing with ethanolamine appropriate mixtures of sulfonic and fatty acids. This method forms the requisite ethanolamine alkyl benzene sulfonate and ethanolamine soap in situ and also provides the free ethanolamine component of the instant composition.
When this preferred composition formulation method is utilized, the total amount of ethanolamine employed will vary with the nature and proportion of the particular alkyl benzene sulfonic and fatty acids and with the particular ethanolamine employed. A highly preferred ethanolamine concentration for formulation of the anionic-ethanolamine portion of the composition is that ethanolamine weight percentage which is approximately equal to the weight percent of anionic surfactant mixture (on a free acid basis) present in any given detergent composition of the instant invention. By adding this preferred amount, ethanolamine will always be present in greater than stoichiometric amount for complete neutralization of the acid mixture and will provide the requisite excess free ethanolamine no matter which ethanolamine is employed and which anionic acid mixture within the limits of the present invention is utilized.
OPTIONAL COMPONENTS
Although the liquid detergent compositions of the instant invention need only contain the above-described three components (i.e., anhydrous compositions), highly preferred compositions of the present invention contain in addition to the three active components a solvent selected from the group consisting of water and water-alcohol mixtures. Generally, such solvents can be added to the extent of from about 1 to 45 percent by weight of the total detergent composition. In preferred compositions the solvent comprises from about 25 to 45 percent by weight. Addition of such solvents has several advantages. First, the physical stability of the detergent compositions can be improved by such solvents in that clear points can thereby be lowered to provide compositions which do not cloud at lower temperatures which might be 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.
Finally, detergent compositions of the instant type containing such solvents are desirable from the standpoint of several safety considerations. More dilute solutions tend to be less toxic and tend to produce less eye irritation than more concentrated or anhydrous detergent compositions containing the three active components.
When an alcohol-water mixture is employed as a solvent, the weight ratio of water to alcohol preferably is maintained above about 3:1, more preferably from about 4:1 to about 7:1. Alcohol (particularly ethanol) concentrations higher than this in water-alcohol mixtures used in the instant invention are preferably avoided because of flammability problems which arise at higher alcohol levels.
Any alcohol containing from 1 to about 5 carbon atoms can be employed in the water-alcohol mixture if such a mixture is utilized in the instant detergent compositions. Examples of operable alcohols include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, and pentanol. From toxicological standpoint, ethanol is highly preferred.
A second optional component which may be added to the detergent compositions of the instant invention is an electrolyte salt. Addition of an electrolyte salt serves to lessen gel formation which tends to occur upon dilution of the instant detergent compositions. When used in combination with a water-alcohol solvent, from about 0.5 to 5 percent by weight of an electrolyte salt can completely eliminate gel formation without utilization of alcohol levels which exceed the flammability safety levels discussed above.
Suitable electrolyte salts include the alkali metal, chlorides, sulfates and carbonates, and the salts formed from the reaction of ethanolamines with formic, acetic, propionic, butyric, citric or sulfuric acid. Specific examples of such salts include sodium chloride, potassium chloride, sodium carbonate, potassium carbonate, potassium sulfate, sodium sulfate, triethanolamine sulfate, triethanolamine citrate, triethanolamine acetate, triethanolamine formate, monoethanolamine propionate and diethanolamine butyrate. Potassium chloride is preferred and is preferably added to the instant compositions to the extent of from about 1 to 3 percent by weight.
As noted, the employment of a solvent and electrolyte serves to control and regulate gel formation 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. (As noted a gel composition is a "liquid" for purposes of this invention.) Thus compositions containing the three active components in the above-specified concentrations and a water solvent comprising from about 15 to 35 percent by weight will be gel compositions provided no alcohol or electrolyte is present.
Other optional non-essential, non-interfering components may be added to the instant compositions to provide improved performance or aesthetic appeal. Preferred compositions of the invention are those to which a color 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 ethanolamine citrate when added to the instant compositions containing excess ethanolamine. For convenience however, this ethanolamine citrate concentration in 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 percent 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 0.10 percent by weight of composition.
Other optional components include brighteners, fluorescers, enzymes, bleaching agents, anti-microbial agents, corrosion inhibitors and coloring agents. Such components preferably comprise no more than about 3 percent by weight of the total composition.
Utilization of nonionic surfactant to anionic surfactant mixture (free acid basis) ratios of from about 2.5:1 to about 3.5:1 in combination with utilization of excess free ethanolamine is critical to formation of detergent compositions having the unexpected performance and stability characteristics of the instant invention. Formation of mixed micelles which results from employment of the particular nonionic/anionic surfactant ratio of the instant invention provides unexpected detergency performance which is insensitive to water hardness.
Employment of ethanolamine salts and excess ethanolamine also contributes to the effectiveness of the instant detergent compositions. For example, these compositions containing the ethanolamine counterion in combination with excess free ethanolamine are much superior in cleaning polyester/cotton than corresponding compositions containing the more conventional sodium or potassium salts of the anionic surfactant acids and no free ethanolamine.
Compositions of the instant invention are used in two different ways for fabric cleaning. They may be used as pre-treatment agents which are applied in concentrated form directly onto fabric stains prior to fabric washing. The instant compositions are also useful as detergents for conventional fabric laundering operations. Both stain removal and soil removal are attained when the instant compositions are dissolved in washing solution to the extent of about 0.10 percent by weight. (Approximately 1/4 cup per 17-19 gallons of wash water.)
With regard to pre-treatment efficacy, compositions of the instant invention containing the specified components 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 comparable in oily stain removal to that attained with those nonionic surfactants which are particularly useful in such pre-treatment stain removal. On the other hand the specific compositions of the instant invention are far superior to conventional nonionic surfactant-based products for soil removal (especially from cotton) in the wash water under standard home laundering conditions. Detergency performance is in fact comparable to that attained with conventional built granular anionic detergent compositions.
The following examples illustrate the liquid detergent compositions of the instant invention:
EXAMPLE I
One hundred grams of a heavy duty liquid detergent composition are formulated having the following composition: Component Wt. % ______________________________________ Condensation product of 6 moles of 33.0 ethylene oxide with coconut fatty alcohol Triethanolamine salt of linear alkyl 16.1 benzene sulfonic acid wherein the alkyl chain averages 12 carbon atoms in length Triethanolamine oleate 2.3 Free triethanolamine 5.3 Ethanol 5.5 Potassium chloride 2.5 Brighteners, perfume, dye 1.2 Water Balance ______________________________________
In the above composition the weight ratio of nonionic surfactant to anionic surfactant (on a free acid basis) is 2.64:1 and the weight ratio of the acid form of the sulfonate to the acid form of the soap is 7.35:1. The anionic surfactant-ethanolamine portion of this composition is prepared by admixing 11 grams of the C 12 alkyl benzene sulfonic acid, 1.5 grams of oleic acid, and 11 grams of triethanolamine.
Such a composition is a stable clear liquid detergent which does not gel upon dilution with water, which is relatively non-toxic (LD 50 = 8 ml./kg.; ED 50 < 1 ml./kg.) which is stable to freeze-thaw, which is relatively non-flammable (Tagliabue Open Cup Flash Point = about 157°F), which provides consistent medium-high sudsing in wash water of varying temperature and hardness and which provides excellent pre-treatment and wash water detergency performance. Addition of 0.05 grams of citric acid to the above-described compositions markedly improves its color stability.
Several heavy duty liquid detergent compositions are formulated having the compositions set forth in Table 1. The combination of the anionic and ethanolamine components in such compositions are all prepared by ethanolamine neutralization of the acid form of the anionic surfactants as described in Example I.
TABLE 1 ____________________________________________________________ ______________ EXAMPLE NO. COMPONENT - % Wt. II III IV V VI VII VIII IX X XI ____________________________________________________________ ______________ Condensation product of 6 52.8 52.8 41.1 33.8 41.1 moles of ethylene oxide with coconut fatty alcohol Kyro EOB (HLB=13.3) 1 52.8 Condensation product of 9.5 52.8 33.0 moles of ethylene oxide with nonyl phenol Pluronic L-43 2 41.1 (HLB = 12) Tetronic 704 3 52.8 (HLB = 15) Ethanolamine*salt of linear 25.6 12.8 25.6 20.0 16.2 16.5 25.6 alkyl benzene sulfonic acid wherein the alkyl chain averages 12 carbon atoms in length Ethanolamine* salt of 16.0 20.8 11.1 tetrapropylene benzene sulfonic acid Ethanolamine* salt of 2.3 2.3 11.6 oleic acid Ethanolamine* salt of 13.6 1.5 1.8 1.2 1.5 tallow fatty acid Mixture in a 3:1 weight 1.5 1.1 ratio of the ethanolamine* salt of tallow fatty acid and the ethanolamine* salt of a saturated fatty acid known commercially as Hyfac Free triethanolamine 8.9 8.7 8.9 6.5 5.2 5.9 8.9 6.2 Free monoethanolamine 10.7 14.0 Ethanol 2.3 5.1 5.1 17.0 Butanol 5.5 Potassium chloride 1.0 Triethanolamine acetate 2.5 Potassium carbonate 1.0 Minors (Brighteners, color 0.9 0.9 0.9 1.2 1.4 1.2 0.9 0.9 0.9 1.2 stabilizers, perfume color- ing agents) Water Balance Weight ratio of nonionic 2.84 3.00 2.84 2.70 2.64 2.70 2.84 2.81 2.84 2.70 surfactant to anionic sur- factant (on an anionic free acid basis) Weight ratio of the acid 11.7 1.0 17.6 9.1 7.3 9.1 11.7 16.1 17.6 1.0 form of the sulfonate com- ponent to acid form of the soap component ____________________________________________________________ ______________ *Triethanolamine salt for Compositions 1-5 and 8-9; Monoethanolamine sal for Compositions 6 and 7 1 Ethoxylated fatty alcohol 2 Condensation product of ethylene oxide with a hydrophobic base formed by condensing propylene oxide with propylene glycol 3Condensation product of ethylene oxide with the compound resulting from the reaction of propylene oxide and ethylene diamine
Examples II through XI represent various detergent compositions within the scope of the present invention. Examples II, III, IV, VIII and X represent highly concentrated liquid detergent systems. Examples V, VI, VII and XI are lower in active detergent content. Example XI represents a detergent gel. All the compositions provide excellent pre-treatment performance when employed directly on fabric stains and provide excellent detergency performance when employed to the extent of about 1/4 cup per 17-19 gallons of wash water.
WASH-WEAR TEST
Wash water detergency performance for several of the compositions of the instant invention was compared with that of a commercially available built granular laundry detergent in a wash and wear test. The test employed was conducted in the following manner: White dress shirts, cotton T-shirts and other fabrics were distributed among various individuals. Each dress shirt and T-shirt was worn for one normal working day under uniform conditions, and the other articles were used for their generally intended purposes. The soiled clothes and fabrics were then washed in an automatic agitating type washer, for a period of 10 minutes, with detergent solutions at 105°F. The detergents employed were the compositions of Examples II, III, IX and X at a concentration of 1/4 cup per 17 gallons of water, and Tide, a commercially available built granular detergent marketed by The Procter & Gamble Co., used at concentrations of both 11/4 cup and 1 cup per 17 gallons of water. The wash water for the liquid detergent solutions had a pH of about 7.2 and for the Tide solutions about 9.5. Wash water hardness was about 7 grains per gallon. After washing, the clothes were rinsed (six spray rinses and one deep rinse) and then dried.
Direct visual comparisons were made by a panel of expert graders between pairs of shirts and fabrics worn and soiled by the same individual. The dress shirts, T-shirts and other fabrics used were graded on the degree of whiteness and the degree of cleaning obtained, paying particular attention on this latter feature to the dress shirt collars and cuffs. For purposes of this invention, the tern "cleaning" or "cleanliness" measures the ability of a washing composition to remove actual soil lines or deposits such as at crease lines of collars and cuffs where the soil has had an opportunity to become deeply embedded. Whiteness, on the other hand, is a more general concept which measures the ability of a cleaning composition to whiten areas which are only slightly or moderately soiled. The relative cleaning effectiveness of each detergent composition in each area was graded visually on a nine point scale under artificial light wherein the highest grade was assigned to the relatively best performance obtained.
Based upon such comparisons, it was found that all of the liquid detergent compositions of the instant invention provided cleaning comparable to 11/4 cups of Tide. Further, all compositions of the instant invention provided combined whiteness performance comparable to 11/4 cups of Tide. except for dilute Example IV which provided combined whiteness performance comparable to 1 cup of Tide.
OILY STAIN REMOVAL TEST
A representative composition of the instant invention was compared with other commercially available laundry products in its ability to remove various types of oily stains from polyester/cotton (65/35 percent) fabrics. Swatches of 11 × 11 inch olive-colored polyester/cotton were stained with one drop each of "Crisco" cooking oil, bacon grease, mineral oil, dirty engine oil, French dressing and suntan oil and aged for 16-20 hours. Four of these swatches were used for each product tested. The first swatch had 1 cc. of product applied directly to each stain; the second 2 cc. per stain; the third, 3 cc. per stain; and the fourth, 4 cc. per stain. After product was applied, each stain was rubbed 10 seconds horizontally and 5 seconds vertically to simulate in-home pretreatment practice.
The products tested were (1) the citric acid-containing liquid detergent composition for Example I above; (2) a commercially available built heavy duty liquid detergent; (3) a commercially available unbuilt heavy duty liquid detergent; and (4) a 50 percent water-product paste made from a granular built laundry detergent, Tide, marketed by The Procter & Gamble Co.
For each product the four swatches as prepared above were washed in an automatic washing machine containing 18.5 gallons of water of 7 grains/gallon hardness at 125°F and a standard family wash load. Each load contained approximately enough of the product being tested (including that already rubbed into the four swatches) to provide the "recommended" usage concentration in wash water solution, i.e., Example I Composition -- 1/4 cup; build liquid -- 1/2 cup; unbuilt liquid -- 1/4 cup; and Tide -- 1 cup.
Each stain on each swatch was graded by two graders on a 0 to 10 scale with 0 corresponding to no stain removal and 10 corresponding to complete stain removal. Grades for the six stains were totaled and divided by 60. This quotient was multiplied by 100 in order to provide a composite Stain Removal Index for each swatch. Results of the test are summarized in Tables 2 and 3 below:
TABLE 2 ____________________________________________________________ ______________ EXAMPLE I COMPOSITION COMMERCIAL BUILT LIQUID 1 cc/ 2 cc/ 3 cc/ 4 cc/ 1 cc/ 2 cc/ 3 cc/ 4 cc/ stain stain stain stain stain stain stain stain ____________________________________________________________ ______________ Crisco oil 9.5 8.0 9.0 9.5 7.5 7.0 6.5 6.5 Bacon grease 8.5 8.5 8.5 8.0 6.0 6.5 5.5 7.0 Mineral oil 9.5 9.5 9.5 9.5 7.0 7.5 6.5 7.5 Dirty Engine oil 9.5 8.0 8.0 8.5 7.5 6.0 6.5 6.0 French Dressing 10.0 9.5 9.0 9.5 7.5 7.0 6.5 7.0 Suntan oil 10.0 10.0 9.5 9.5 7.0 7.0 7.5 7.0 TOTAL 57.0 53.5 53.5 54.5 42.5 41.0 39.0 41.0 STAIN REMOVAL INDEX 95.0 89.1 89.1 90.8 70.8 68.3 65.0 68.3 ____________________________________________________________ ______________
TABLE 3 ____________________________________________________________ ______________ COMMERCIAL UNBUILT LIQUID TIDE PASTE 1 cc/ 2 cc/ 3 cc/ 4 cc/ 1 cc/ 2 cc/ 3 cc/ 4 cc/ stain stain stain stain stain stain stain stain ____________________________________________________________ ______________ Crisco oil 6.5 6.0 6.5 7.5 4.0 2.5 3.0 2.5 Bacon grease 5.0 7.0 5.5 6.5 3.0 2.5 3.0 1.5 Mineral oil 6.5 7.0 6.5 7.5 3.0 2.0 3.5 1.5 Dirty Engine oil 3.5 6.5 4.5 5.5 1.5 1.5 1.5 1.5 French Dressing 7.0 5.5 6.5 9.0 2.5 2.5 2.5 3.5 Suntan oil 6.0 7.5 6.0 8.5 2.5 2.0 1.5 2.0 TOTAL 34.5 39.5 35.5 44.5 16.5 13.0 15.0 12.5 STAIN REMOVAL INDEX 57.5 65.8 59.1 74.1 27.5 21.6 25.0 20.8 ____________________________________________________________ ______________
From these results it can be seen that the composition of the instant invention was generally superior to the other formulations in removng oily stains from polyester-containing fabric.
SUDSING PERFORMANCE TEST
The unusual sudsing consistency of the instant heavy duty liquid detergent compositions is demonstrated by the following suds height evaluation. The citric acid-containing composition of Example I was used under varying conditions of water temperature and water hardness in a General Electric top-loading automatic washer at a concentration of 1/4 cup per 17 gallons with a standard wash load. After 10 minutes, suds heights were measured in inches and averaged for 24 runs under each set of conditions. Results of such sudsing experiments are summarized below.
______________________________________ Suds Height Conditions Average (Inches) ______________________________________ 70°F.; 7 grains 2.6 100°F.; 2 grains 3.4 100°F.; 7 grains 3.4 100°F.; 14 grains 2.5 125°F.; 7 grains 2.6 140°F.; 2 grains 2.8 140°F.; 7 grains 3.1 ______________________________________
It can be seen that under a variety of temperature and hardness conditions, the composition of the instant invention provided average suds heights varying no more than one inch.
The present invention relates to concentrated heavy duty liquid detergent compositions. As used herein, the term "liquid" encompasses semi-liquid or gel compositions as well as more conventional freely-flowing formulations. Such compositions contain a nonionic surfactant component, a mixture of anionic surfactants and an ethanolamine component.
Heavy duty liquid detergent compositions are wellknown in the art. Usually such compositions (see, for example, U.S. Pat. Nos. 2,908,651; 2,920,045; 3,272,753, 3,393,154; and Belgian Pat. Nos. 613,165 and 665,532) contain a synthetic organic detergent component which is generally anionic, nonionic, 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 solubilizing 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 compositions 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 if such compositions are employed on a broad scale.
Several attempts have been made to formulate builderfree, hydrotrope-free liquid detergent compositions. For example, U.S. Pat. No. 3,528,925 discloses substantially anhydrous liquid detergent compositions which consist of alkyl aryl sulfonic acid, a nonionic surface active agent and an alkanolamine component. U.S. Pat. No. 2,875,153 discloses liquid detergent compositions containing a nonionic surfactant component and a sodium soap component. U.S. Pat. No. 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 as pre-treatment and heavy duty washing agents for cleaning both natural and synthetic fabrics.
Accordingly, it is an object of the present invention to provide concentrated heavy duty liquid detergent compositions which are highly effective on all types of fabrics both as stain pre-treatment agents and as laundry washing agents.
It is a further object of the instant invention to provide liquid detergent compositions which are free of inorganic builders and conventional hydrotropes.
It is a further object of the instant invention to formulate such heavy duty liquid detergent compositions which are chemically and physically stable and which are relatively non-toxic and non-irritating.
It has been discovered that by employing particular nonionic and anionic surfactants in combination with certain ethanolamine compounds in very specific ratios of such components, these above-described objectives can be attained, and liquid detergent compositions can be formulated which are unexpectedly superior to liquid detergent compositions presently known to the prior art.
SUMMARY OF THE INVENTION
The present invention provides liquid detergent compositions consisting essentially of (a) from about 30 to about 60 percent by weight of a nonionic surfactant produced by the condensation of alkylene oxide with an organic hydrophobic compound; (b) an anionic surfactant mixture (as hereinafter defined) in an amount sufficient to provide a weight ratio of nonionic surfactant to anionic surfactant mixture within the range of from about 2.5:1 to about 3.5:1 based on the free acid form of the anionic surfactants; and (c) an ethanolamine in an amount sufficient to provide at least 1 percent by weight of the composition of ethanolamine.
The anionic surfactant mixture consists of two components: (1) a mono-, di- or tri-ethanolamine alkyl benzene sulfonate having from about 9 to about 15 carbon atoms in the alkyl chain; and (2) a mono-, di- or tri-ethanolamine soap containing from about 8 to about 24 carbon atoms in the fatty acid moiety thereof. These two components of the anionic surfactant mixture are present in quantities sufficient to provide a weight ratio of the acid form of the sulfonate to the acid form of the soap of from about 20:1 to about 1:1.
DESCRIPTION OF THE INVENTION
The components of the instant detergent compositions are discussed in detail as follows:
THE NONIONIC SURFACTANT
From about 30 to about 60 percent by weight of the liquid detergent compositions of the present invention consists of a nonionic surfactant derived by the condensation of an alkylene oxide (hydrophilic in nature) with an organic hydrophobic compound, which is usually aliphatic or alkyl aromatic in nature. The length of the hydrophilic or polyoxyalkylene moiety which is condensed with any particular hydrophobic compound can be readily adjusted to yield a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements. Examples of suitable nonionic surfactants are:
1. The polyethylene oxide condensates of alkyl phenols. These compounds include the condensation products of alkyl phenols having an alkyl group containing from about 6 to 12 carbon atoms in either a straight chain or branched chain configuration, with ethylene oxide, the said ethylene oxide being present in amounts equal to 5 to 25 moles of ethylene oxide per mole of alkyl phenol. The alkyl substituent in such compounds may be derived, for example, from polymerized propylene, diisobutylene, octene, or nonene. Examples of compounds of this type include nonyl phenol condensed with about 9.5 moles of ethylene oxide per mole of nonyl phenol, dodecyl phenol condensed with about 12 moles of ethylene oxide per mole of phenol, di- nonyl phenol condensed with about 15 moles of ethylene oxide per mole of phenol, di-isooctylphenol condensed with about 15 moles of ethylene oxide per mole of phenol. Commercially available nonionic surfactants of this type include Igepal CO-630 marketed by the GAF Corp.; and Triton X-45, X-114, X-100 and X-102, all marketed by the Rohm and Haas Co.
2. The condensation products of aliphatic alcohols with ethylene oxide. The alkyl chain of the aliphatic alcohol may either be straight or branched and generally contains from about 8 to about 22 carbon atoms. Examples of such ethoxylated alcohols include the condensation product of about 6 moles of ethylene oxide with 1 mole of tridecanol, myristyl alcohol condensed with about 10 moles of ethylene oxide per mole of myristyl alcohol, the condensation product of ethylene oxide with coconut fatty alcohol wherein the coconut alcohol is a mixture of fatty alcohols with alkyl chains varying from 10 to 14 carbon atoms in length and wherein the condensate contains about 6 moles of ethylene oxide per mole of alcohol, and the condensation product of about 9 moles of ethylene oxide with the above-described coconut alcohol. Examples of commercially available nonionic surfactants of this type include Tergitol 15-S-9 marketed by the Union Carbide Corp., Neodol 23-6.5 marketed by the Shell Chemical Co. and Kyro EOB marketed by the Procter & Gamble Co.
3. The condensation products of ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol. The hydrophobic portion of these compounds has a molecular weight of from about 1,500 to 1,800 and of course exhibits water insolubility. The addition of polyoxyethylene moieties to this hydrophobic portion tends to increase the water-solubility of the molecule as a whole, and the liquid character of the product is retained up to the point where the polyoxyethylene content is about 50 percent of the total weight of the condensation product. Examples of compounds of this type include certain of the commercially available Pluronic surfactants marketed by the Wyandotte Chemicals Corp.
4. The condensation products of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylene diamine. The hydrophobic base of these products consists of the reaction product of ethylene diamine and excess propylene oxide, said base having a molecular weight of from about 2,500 to about 3,000. This base is condensed with ethylene oxide to the extent that the condensation product contains from about 40 to about 80 percent by weight of polyoxyethylene and has a molecular weight of from about 5,000 to about 11,000. Examples of this type of nonionic surfactant include certain of the commercially available Tetronic compounds marketed by the Wyandotte Chemicals Corp.
For use in the detergent compositions of the instant invention, it is preferred that the particular nonionic surfactant employed have a hydrophilic-lipophilic balance (HLB) of from about 8 to about 15. A highly preferred nonionic surfactant within this range is the condensation product of 6 moles of ethylene oxide with coconut fatty alcohol. (HLB = 12)
The presence of the nonionic surfactant in the instant liquid detergent compositions in the essential specified concentration provides the necessary oily stain removal in both pre-treatment application and wash water utilization of the instant invention. Such nonionic surfactant also contributes to the physical stability of the liquid detergent compositions.
THE ANIONIC SURFACTANT MIXTURE
The anionic component of the instant detergent compositions consists of a mixture of an ethanolamine salt of an alkylbenzene sulfonic acid (an ethanolamine alkylbenzene sulfonate) and an ethanolamine salt of a fatty acid (hereinafter referred to as an ethanolamine soap). Both of these salts are prepared by neutralizing the corresponding anionic acids with an ethanolamine selected from the group consisting of monoethanolamine, diethanolamine and triethanolamine. The mixture of anionic surfactant salts is employed herein in a quantity sufficient to provide a weight ratio of nonionic surfactant to anionic surfactant mixture of from about 2.5:1 to about 3.5:1, based on the free acid form of the anionic surfactants.
The non-soap component of the anionic surfactant mixture consists of a mono-, di- or tri-ethanolamine salt of a straight or branched chain alkyl benzene sulfonic acid in which the alkyl group contains from about 9 to about 15 carbon atoms. Preferred surfactants of this type are those in which the alkyl chain is linear and averages about 12 carbon atoms in length. Examples of ethanolamine alkyl benzene sulfonates useful in the instant invention include monoethanolamine decyl benzene sulfonate, diethanolamine undecyl benzene sulfonate, triethanolamine dodecyl benzene sulfonate, monoethanolamine tridecyl benzene sulfonate, triethanolamine tetradecyl benzene sulfonate and diethanolamine tetrapropylene benzene sulfonate. Examples of commercially available alkyl benzene sulfonic acids useful in preparing the ethanolamine sulfonates of the instant invention include Conoco SA 515, SA 597, and SA 697 all marketed by the Continental Oil Co. and Calsoft LAS 99 marketed by the Pilot Chemical Co.
The soap component of the anionic surfactant mixture consists of mono-, di- and triethanolamine soaps of fatty acids containing from about 8 to about 24 carbon atoms and 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, grease, lard, 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 suitable soaps for use in the instant invention include monoethanolamine caproate, diethanolamine laurate, triethanolamine myristate, triethanolamine palmitate, monoethanolamine stearate and diethanolamine palmitoleate. Preferred soaps include the mono-, di- and triethanolamine soaps of mixtures of fatty acids derived from coconut oil and tallow. A highly preferred soap for use in the instant invention is triethanolamine oleate. Examples of commercially available fatty acids for use in preparing the ethanolamine soaps of the instant invention include C-105, C-108, C-110, T-10, T-11 and OL-910 all marketed by The Proctor & Gamble Co., and Hyfac, a hydrogenated fish oil fatty acid marketed by Emery Industries, Inc.
Within the anionic surfactant mixture, the two components thereof are present in quantities sufficient to provide a weight ratio of the acid form of the sulfonate (an alkyl benzene sulfonic acid) to the acid form of the soap (a fatty acid) of from about 20:1 to about 1:1, preferably from about 4:1 to 8:1. It has been found that anionic mixture component weight ratios within this range provide an unexpectedly high degree of soil and stain removal and at the same time maintain excellent suds control during both wash and rinse.
As noted, the anionic surfactant mixture as a whole must be present in the instant liquid detergent compositions to such an extent that the weight ratio of nonionic surfactant to anionic surfactant (calculated on a free anionic acid basis) is approximately 3:1, i.e., from about 2.5:1 to about 3.5:1. The reasons for this essential weight ratio limitation will be discussed more fully below.
THE ETHANOLAMINE
A third essential component of the liquid detergent composition of the present invention is the ethanolamine compound. The ethanolamine useful herein is selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine and mixtures thereof. Mixtures of these three ethanolamine compounds are produced by the reaction of ethylene oxide with ammonia. The pure compounds can be separated from this mixture by standard distillation procedures.
The ethanolamine 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 ethanolamine neutralizes the free acid form of the anionic surfactant mixture to provide the corresponding ethanolamine salts which are essential components of the instant detergent compositions. In addition, the excess ethanolamine beyond that necessary to form the anionic surfactant salts in accordance with the invention contributes to detergency performance and serves as a buffering agent which maintains wash 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 percent by weight of the total composition of free ethanolamine.
The above-described compositions containing nonionic, anionic and ethanolamine components can be formulated 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 ethanolamine components are formulated simultaneously by over-neutralizing with ethanolamine appropriate mixtures of sulfonic and fatty acids. This method forms the requisite ethanolamine alkyl benzene sulfonate and ethanolamine soap in situ and also provides the free ethanolamine component of the instant composition.
When this preferred composition formulation method is utilized, the total amount of ethanolamine employed will vary with the nature and proportion of the particular alkyl benzene sulfonic and fatty acids and with the particular ethanolamine employed. A highly preferred ethanolamine concentration for formulation of the anionic-ethanolamine portion of the composition is that ethanolamine weight percentage which is approximately equal to the weight percent of anionic surfactant mixture (on a free acid basis) present in any given detergent composition of the instant invention. By adding this preferred amount, ethanolamine will always be present in greater than stoichiometric amount for complete neutralization of the acid mixture and will provide the requisite excess free ethanolamine no matter which ethanolamine is employed and which anionic acid mixture within the limits of the present invention is utilized.
OPTIONAL COMPONENTS
Although the liquid detergent compositions of the instant invention need only contain the above-described three components (i.e., anhydrous compositions), highly preferred compositions of the present invention contain in addition to the three active components a solvent selected from the group consisting of water and water-alcohol mixtures. Generally, such solvents can be added to the extent of from about 1 to 45 percent by weight of the total detergent composition. In preferred compositions the solvent comprises from about 25 to 45 percent by weight. Addition of such solvents has several advantages. First, the physical stability of the detergent compositions can be improved by such solvents in that clear points can thereby be lowered to provide compositions which do not cloud at lower temperatures which might be 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.
Finally, detergent compositions of the instant type containing such solvents are desirable from the standpoint of several safety considerations. More dilute solutions tend to be less toxic and tend to produce less eye irritation than more concentrated or anhydrous detergent compositions containing the three active components.
When an alcohol-water mixture is employed as a solvent, the weight ratio of water to alcohol preferably is maintained above about 3:1, more preferably from about 4:1 to about 7:1. Alcohol (particularly ethanol) concentrations higher than this in water-alcohol mixtures used in the instant invention are preferably avoided because of flammability problems which arise at higher alcohol levels.
Any alcohol containing from 1 to about 5 carbon atoms can be employed in the water-alcohol mixture if such a mixture is utilized in the instant detergent compositions. Examples of operable alcohols include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, and pentanol. From toxicological standpoint, ethanol is highly preferred.
A second optional component which may be added to the detergent compositions of the instant invention is an electrolyte salt. Addition of an electrolyte salt serves to lessen gel formation which tends to occur upon dilution of the instant detergent compositions. When used in combination with a water-alcohol solvent, from about 0.5 to 5 percent by weight of an electrolyte salt can completely eliminate gel formation without utilization of alcohol levels which exceed the flammability safety levels discussed above.
Suitable electrolyte salts include the alkali metal, chlorides, sulfates and carbonates, and the salts formed from the reaction of ethanolamines with formic, acetic, propionic, butyric, citric or sulfuric acid. Specific examples of such salts include sodium chloride, potassium chloride, sodium carbonate, potassium carbonate, potassium sulfate, sodium sulfate, triethanolamine sulfate, triethanolamine citrate, triethanolamine acetate, triethanolamine formate, monoethanolamine propionate and diethanolamine butyrate. Potassium chloride is preferred and is preferably added to the instant compositions to the extent of from about 1 to 3 percent by weight.
As noted, the employment of a solvent and electrolyte serves to control and regulate gel formation 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. (As noted a gel composition is a "liquid" for purposes of this invention.) Thus compositions containing the three active components in the above-specified concentrations and a water solvent comprising from about 15 to 35 percent by weight will be gel compositions provided no alcohol or electrolyte is present.
Other optional non-essential, non-interfering components may be added to the instant compositions to provide improved performance or aesthetic appeal. Preferred compositions of the invention are those to which a color 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 ethanolamine citrate when added to the instant compositions containing excess ethanolamine. For convenience however, this ethanolamine citrate concentration in 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 percent 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 0.10 percent by weight of composition.
Other optional components include brighteners, fluorescers, enzymes, bleaching agents, anti-microbial agents, corrosion inhibitors and coloring agents. Such components preferably comprise no more than about 3 percent by weight of the total composition.
Utilization of nonionic surfactant to anionic surfactant mixture (free acid basis) ratios of from about 2.5:1 to about 3.5:1 in combination with utilization of excess free ethanolamine is critical to formation of detergent compositions having the unexpected performance and stability characteristics of the instant invention. Formation of mixed micelles which results from employment of the particular nonionic/anionic surfactant ratio of the instant invention provides unexpected detergency performance which is insensitive to water hardness.
Employment of ethanolamine salts and excess ethanolamine also contributes to the effectiveness of the instant detergent compositions. For example, these compositions containing the ethanolamine counterion in combination with excess free ethanolamine are much superior in cleaning polyester/cotton than corresponding compositions containing the more conventional sodium or potassium salts of the anionic surfactant acids and no free ethanolamine.
Compositions of the instant invention are used in two different ways for fabric cleaning. They may be used as pre-treatment agents which are applied in concentrated form directly onto fabric stains prior to fabric washing. The instant compositions are also useful as detergents for conventional fabric laundering operations. Both stain removal and soil removal are attained when the instant compositions are dissolved in washing solution to the extent of about 0.10 percent by weight. (Approximately 1/4 cup per 17-19 gallons of wash water.)
With regard to pre-treatment efficacy, compositions of the instant invention containing the specified components 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 comparable in oily stain removal to that attained with those nonionic surfactants which are particularly useful in such pre-treatment stain removal. On the other hand the specific compositions of the instant invention are far superior to conventional nonionic surfactant-based products for soil removal (especially from cotton) in the wash water under standard home laundering conditions. Detergency performance is in fact comparable to that attained with conventional built granular anionic detergent compositions.
The following examples illustrate the liquid detergent compositions of the instant invention:
EXAMPLE I
One hundred grams of a heavy duty liquid detergent composition are formulated having the following composition: Component Wt. % ______________________________________ Condensation product of 6 moles of 33.0 ethylene oxide with coconut fatty alcohol Triethanolamine salt of linear alkyl 16.1 benzene sulfonic acid wherein the alkyl chain averages 12 carbon atoms in length Triethanolamine oleate 2.3 Free triethanolamine 5.3 Ethanol 5.5 Potassium chloride 2.5 Brighteners, perfume, dye 1.2 Water Balance ______________________________________
In the above composition the weight ratio of nonionic surfactant to anionic surfactant (on a free acid basis) is 2.64:1 and the weight ratio of the acid form of the sulfonate to the acid form of the soap is 7.35:1. The anionic surfactant-ethanolamine portion of this composition is prepared by admixing 11 grams of the C 12 alkyl benzene sulfonic acid, 1.5 grams of oleic acid, and 11 grams of triethanolamine.
Such a composition is a stable clear liquid detergent which does not gel upon dilution with water, which is relatively non-toxic (LD 50 = 8 ml./kg.; ED 50 < 1 ml./kg.) which is stable to freeze-thaw, which is relatively non-flammable (Tagliabue Open Cup Flash Point = about 157°F), which provides consistent medium-high sudsing in wash water of varying temperature and hardness and which provides excellent pre-treatment and wash water detergency performance. Addition of 0.05 grams of citric acid to the above-described compositions markedly improves its color stability.
Several heavy duty liquid detergent compositions are formulated having the compositions set forth in Table 1. The combination of the anionic and ethanolamine components in such compositions are all prepared by ethanolamine neutralization of the acid form of the anionic surfactants as described in Example I.
TABLE 1 ____________________________________________________________ ______________ EXAMPLE NO. COMPONENT - % Wt. II III IV V VI VII VIII IX X XI ____________________________________________________________ ______________ Condensation product of 6 52.8 52.8 41.1 33.8 41.1 moles of ethylene oxide with coconut fatty alcohol Kyro EOB (HLB=13.3) 1 52.8 Condensation product of 9.5 52.8 33.0 moles of ethylene oxide with nonyl phenol Pluronic L-43 2 41.1 (HLB = 12) Tetronic 704 3 52.8 (HLB = 15) Ethanolamine*salt of linear 25.6 12.8 25.6 20.0 16.2 16.5 25.6 alkyl benzene sulfonic acid wherein the alkyl chain averages 12 carbon atoms in length Ethanolamine* salt of 16.0 20.8 11.1 tetrapropylene benzene sulfonic acid Ethanolamine* salt of 2.3 2.3 11.6 oleic acid Ethanolamine* salt of 13.6 1.5 1.8 1.2 1.5 tallow fatty acid Mixture in a 3:1 weight 1.5 1.1 ratio of the ethanolamine* salt of tallow fatty acid and the ethanolamine* salt of a saturated fatty acid known commercially as Hyfac Free triethanolamine 8.9 8.7 8.9 6.5 5.2 5.9 8.9 6.2 Free monoethanolamine 10.7 14.0 Ethanol 2.3 5.1 5.1 17.0 Butanol 5.5 Potassium chloride 1.0 Triethanolamine acetate 2.5 Potassium carbonate 1.0 Minors (Brighteners, color 0.9 0.9 0.9 1.2 1.4 1.2 0.9 0.9 0.9 1.2 stabilizers, perfume color- ing agents) Water Balance Weight ratio of nonionic 2.84 3.00 2.84 2.70 2.64 2.70 2.84 2.81 2.84 2.70 surfactant to anionic sur- factant (on an anionic free acid basis) Weight ratio of the acid 11.7 1.0 17.6 9.1 7.3 9.1 11.7 16.1 17.6 1.0 form of the sulfonate com- ponent to acid form of the soap component ____________________________________________________________ ______________ *Triethanolamine salt for Compositions 1-5 and 8-9; Monoethanolamine sal for Compositions 6 and 7 1 Ethoxylated fatty alcohol 2 Condensation product of ethylene oxide with a hydrophobic base formed by condensing propylene oxide with propylene glycol 3Condensation product of ethylene oxide with the compound resulting from the reaction of propylene oxide and ethylene diamine
Examples II through XI represent various detergent compositions within the scope of the present invention. Examples II, III, IV, VIII and X represent highly concentrated liquid detergent systems. Examples V, VI, VII and XI are lower in active detergent content. Example XI represents a detergent gel. All the compositions provide excellent pre-treatment performance when employed directly on fabric stains and provide excellent detergency performance when employed to the extent of about 1/4 cup per 17-19 gallons of wash water.
WASH-WEAR TEST
Wash water detergency performance for several of the compositions of the instant invention was compared with that of a commercially available built granular laundry detergent in a wash and wear test. The test employed was conducted in the following manner: White dress shirts, cotton T-shirts and other fabrics were distributed among various individuals. Each dress shirt and T-shirt was worn for one normal working day under uniform conditions, and the other articles were used for their generally intended purposes. The soiled clothes and fabrics were then washed in an automatic agitating type washer, for a period of 10 minutes, with detergent solutions at 105°F. The detergents employed were the compositions of Examples II, III, IX and X at a concentration of 1/4 cup per 17 gallons of water, and Tide, a commercially available built granular detergent marketed by The Procter & Gamble Co., used at concentrations of both 11/4 cup and 1 cup per 17 gallons of water. The wash water for the liquid detergent solutions had a pH of about 7.2 and for the Tide solutions about 9.5. Wash water hardness was about 7 grains per gallon. After washing, the clothes were rinsed (six spray rinses and one deep rinse) and then dried.
Direct visual comparisons were made by a panel of expert graders between pairs of shirts and fabrics worn and soiled by the same individual. The dress shirts, T-shirts and other fabrics used were graded on the degree of whiteness and the degree of cleaning obtained, paying particular attention on this latter feature to the dress shirt collars and cuffs. For purposes of this invention, the tern "cleaning" or "cleanliness" measures the ability of a washing composition to remove actual soil lines or deposits such as at crease lines of collars and cuffs where the soil has had an opportunity to become deeply embedded. Whiteness, on the other hand, is a more general concept which measures the ability of a cleaning composition to whiten areas which are only slightly or moderately soiled. The relative cleaning effectiveness of each detergent composition in each area was graded visually on a nine point scale under artificial light wherein the highest grade was assigned to the relatively best performance obtained.
Based upon such comparisons, it was found that all of the liquid detergent compositions of the instant invention provided cleaning comparable to 11/4 cups of Tide. Further, all compositions of the instant invention provided combined whiteness performance comparable to 11/4 cups of Tide. except for dilute Example IV which provided combined whiteness performance comparable to 1 cup of Tide.
OILY STAIN REMOVAL TEST
A representative composition of the instant invention was compared with other commercially available laundry products in its ability to remove various types of oily stains from polyester/cotton (65/35 percent) fabrics. Swatches of 11 × 11 inch olive-colored polyester/cotton were stained with one drop each of "Crisco" cooking oil, bacon grease, mineral oil, dirty engine oil, French dressing and suntan oil and aged for 16-20 hours. Four of these swatches were used for each product tested. The first swatch had 1 cc. of product applied directly to each stain; the second 2 cc. per stain; the third, 3 cc. per stain; and the fourth, 4 cc. per stain. After product was applied, each stain was rubbed 10 seconds horizontally and 5 seconds vertically to simulate in-home pretreatment practice.
The products tested were (1) the citric acid-containing liquid detergent composition for Example I above; (2) a commercially available built heavy duty liquid detergent; (3) a commercially available unbuilt heavy duty liquid detergent; and (4) a 50 percent water-product paste made from a granular built laundry detergent, Tide, marketed by The Procter & Gamble Co.
For each product the four swatches as prepared above were washed in an automatic washing machine containing 18.5 gallons of water of 7 grains/gallon hardness at 125°F and a standard family wash load. Each load contained approximately enough of the product being tested (including that already rubbed into the four swatches) to provide the "recommended" usage concentration in wash water solution, i.e., Example I Composition -- 1/4 cup; build liquid -- 1/2 cup; unbuilt liquid -- 1/4 cup; and Tide -- 1 cup.
Each stain on each swatch was graded by two graders on a 0 to 10 scale with 0 corresponding to no stain removal and 10 corresponding to complete stain removal. Grades for the six stains were totaled and divided by 60. This quotient was multiplied by 100 in order to provide a composite Stain Removal Index for each swatch. Results of the test are summarized in Tables 2 and 3 below:
TABLE 2 ____________________________________________________________ ______________ EXAMPLE I COMPOSITION COMMERCIAL BUILT LIQUID 1 cc/ 2 cc/ 3 cc/ 4 cc/ 1 cc/ 2 cc/ 3 cc/ 4 cc/ stain stain stain stain stain stain stain stain ____________________________________________________________ ______________ Crisco oil 9.5 8.0 9.0 9.5 7.5 7.0 6.5 6.5 Bacon grease 8.5 8.5 8.5 8.0 6.0 6.5 5.5 7.0 Mineral oil 9.5 9.5 9.5 9.5 7.0 7.5 6.5 7.5 Dirty Engine oil 9.5 8.0 8.0 8.5 7.5 6.0 6.5 6.0 French Dressing 10.0 9.5 9.0 9.5 7.5 7.0 6.5 7.0 Suntan oil 10.0 10.0 9.5 9.5 7.0 7.0 7.5 7.0 TOTAL 57.0 53.5 53.5 54.5 42.5 41.0 39.0 41.0 STAIN REMOVAL INDEX 95.0 89.1 89.1 90.8 70.8 68.3 65.0 68.3 ____________________________________________________________ ______________
TABLE 3 ____________________________________________________________ ______________ COMMERCIAL UNBUILT LIQUID TIDE PASTE 1 cc/ 2 cc/ 3 cc/ 4 cc/ 1 cc/ 2 cc/ 3 cc/ 4 cc/ stain stain stain stain stain stain stain stain ____________________________________________________________ ______________ Crisco oil 6.5 6.0 6.5 7.5 4.0 2.5 3.0 2.5 Bacon grease 5.0 7.0 5.5 6.5 3.0 2.5 3.0 1.5 Mineral oil 6.5 7.0 6.5 7.5 3.0 2.0 3.5 1.5 Dirty Engine oil 3.5 6.5 4.5 5.5 1.5 1.5 1.5 1.5 French Dressing 7.0 5.5 6.5 9.0 2.5 2.5 2.5 3.5 Suntan oil 6.0 7.5 6.0 8.5 2.5 2.0 1.5 2.0 TOTAL 34.5 39.5 35.5 44.5 16.5 13.0 15.0 12.5 STAIN REMOVAL INDEX 57.5 65.8 59.1 74.1 27.5 21.6 25.0 20.8 ____________________________________________________________ ______________
From these results it can be seen that the composition of the instant invention was generally superior to the other formulations in removng oily stains from polyester-containing fabric.
SUDSING PERFORMANCE TEST
The unusual sudsing consistency of the instant heavy duty liquid detergent compositions is demonstrated by the following suds height evaluation. The citric acid-containing composition of Example I was used under varying conditions of water temperature and water hardness in a General Electric top-loading automatic washer at a concentration of 1/4 cup per 17 gallons with a standard wash load. After 10 minutes, suds heights were measured in inches and averaged for 24 runs under each set of conditions. Results of such sudsing experiments are summarized below.
______________________________________ Suds Height Conditions Average (Inches) ______________________________________ 70°F.; 7 grains 2.6 100°F.; 2 grains 3.4 100°F.; 7 grains 3.4 100°F.; 14 grains 2.5 125°F.; 7 grains 2.6 140°F.; 2 grains 2.8 140°F.; 7 grains 3.1 ______________________________________
It can be seen that under a variety of temperature and hardness conditions, the composition of the instant invention provided average suds heights varying no more than one inch.