CA1230534A - Stabilized oil-in-water cleaning microemulsions - Google Patents

Abstract

STABILIZED OIL-IN-WATER CLEANING
MICROEMULSIONS
ABSTRACT

Solvent-containing liquid detergent compositions containing degreasing solvents such as n-octyl benzene, terpenes or olefins are prepared with high levels of fatty acid/soap at a pH of ca. 6.5.
The compositions are pH-adjusted to neutrality or the alkaline pH range using various amines, amine oxides or quaternary ammonium salts.

Description

~:3~34 STABILIZED OIL-IN-WATER CLEANING MICROEMULSIONS

James Pyott JOHNSTON
John Richard WALKER
Ivan HERBOTS

TECHNICAL FIELD

The present invention relates to methods for ad-justing the pH of carboxylic acid-containing oil-in-water microemulsions towards the alkaline range using a variety of nitrogen-functional ingredients such as amines, quaternary ammonium salts and amine oxides.
Liquid laundry detergent compositions, liquid hard sur-face cleaners, and the like, are thereby provided.

BACKGROUND
Various organic solvents, for example terpenes and terpene-like compounds, are rather well-known for use in hard surface cleaners for their grease removal abi-lity. Such cleaners often contain 10%, or more, of a solvent such as d-limonene, together with a surfactant, especially nonionic surfactants which are also well-known for their grease removal performance. Such compositions have also been suggested for cleaning carpets. British Patent 1 603 047, 1981. EPO applica-tion 0 040 882 published December 2, 1981 discloses hard surface cleaners comprising a mixture of benzyl alcohol, terpenes, surfactants and other detersive ingredients.

.~ .

~1230534 European Patent Application 0 072 488 (published February 23, 1983) suggests that terpenes such as d-limonene can be incorporated into fabric pre-treating compositions as a non-homogeneous emulsion. Such emulsions are apparently designed to be packaged in relatively small volume containers which can be shaken immediately prior to use to restore some semblance of homogeneity, then dispensed directly onto fabrics by spraying.
Clear emulsions comprising water, surfactant and various other solvents are disclosed by Davidsohn in 3rd International Congress of Surface Activity, Cologne (1960).
Terpineols, e.g. from pine oil, have been disclosed for use in wet-scouring of textiles. In particular, in 1937, U.S. Patent 2.073.464 disclosed clear compositions which can be prepared from pine oil terpineol such as alpha terpineol and fatty acid soap or free acid neu-tralized in situ to alkaline pH.
More recently, an article in Soap Perfumery Cosmetics April 1983, pages 174, 175 suggests that only low levels of terpenes (3%) can be incorporated into heavy duty liquid detergents.
Citrus juices, which contain relatively low amounts of terpenes, have been suggested for use in hand soaps and dishwashing liquids. UOS. Patent 3.650.968; Memoire descriptif 873,051 (relating to Brevet Anglais 53472/77, 22 December 1977).
The use of relatively high concentrations of sol-vents in heavy duty liquid laundry detergents offers many advantages. The liquid form of such products al-lows them to be used as pre-treatment agents. When used through-the-wash, solvents such as terpenes, certain alkyl-aromatics and certain olefin hydrocarbon solvents, have now been found to provide additional cleaning benefits over and above those provided by detersive ~ 33 ~

surfactants. Unfo~tunately, the non-homog~neity of compositions such as those disclosed in EPO 0 072 48a makes them inconvenient for use as a general purpose laundry deteryent, since most heavy duty liquid detergents are packayed in relatively large containers which are unhandy for the user to shake thoroughly.
The present ;nvention provides fully-formulated heavy duty liquid detergent compositions comprisiny as much as 20%, and higher, by weight of essentially water-insoluble solvent, in the form of homogeneous, fatty acid-built liquids that are quite suitable for use in both the fabric pre-treatment and through-the-wash laundry modes, as hard-surface cleaners, and the like.
Importantly, means are disclosed which allows such compositions to be formulated as stable microemulsions at pH's above their "as is" formulation pH oE about 6.5 SUMMARY OF THE I~VENTION
The present invention encompasses means for adjusting the p~ of an oil-in-water microemulsion typically comprising a mixture of water (l0~ to 70%), grease--removal solvent or solvent mixture (5~ to 20%), fatty acid or fatty acid~soap mixture (5% to 35%) and detersive surfactant (1% to 40%), together with optional detersive ingredients (generally 0.1% to 15%), by admixing therewi-th a nitrogen-functional material such as an amine, a quaternary ammonium salt, or an amine oxide, whereby the "as is" pH of said microemulsion is adjusted from its original pH of around 5.5 towards a neutral or alkaline pH, whereby the cleaning performance, especially enzyme cleaning action, of said microemulsion i8 improved.
The invention also encompasses compositions prepared in the foregoing manner, as well as methods of cleaning fabrics and hard surfaces using said compositions.

~L230534 pETAILED DESCRIPTION OF T~E INVENTION
The essential solvent, fatty acid (or soap) and water emulsification system, the detersive surfactant components, the means for stabilizing the formulation at pH~s above 6.5, and various other optional ingredients used in the practice of the present invention are described in more detail, hereinafter. All percentages and ratios mentioned in this application are by weight, unless otherwise stated.
Solvent - The solvents employed herein can be any of the well-known "degreasing" solvents commonly known for use, in, for example, the commercial laundry and dry-cleaning industry, in the hard-surface cleaner industry and the metalworking industry. Typically, such solvents comprise hydrocarbon or halogenated hydrocarbon moieties of the alkyl or cyclo-alkyl type, and have a boiling point well above room temperature.
The formulator of compositions of the present type will be guided in the selection of solvent partly by the need to provide good grease-cutting properties, and partly by aesthetic considerations. For example, kerosene hydrocarbons function quite well in the present compositions, but can be malodorous. Kerosene can be used in commercial laundries. For home use, where malodors would not be tolerated, the formulator would be more likely to select solvents which have a relatively pleasant odor, or odors which can be reasonably modified by perfuming. Such solvents include, for example, the terpenes and terpenoid solvents obtainable from citrus fruits, especially orange terpenes and d-limonene. Benzyl alcohol is another relatively pleasant smelling solvent for use herein. Mixtures of orange terpene and benzyl alcohol are especially suitable for removing certain types of stains, e.g. marker ink, shoe polish, and dirty motor Oil, 12305i~

Accordinyly, one preferred class of solvents used herein are the liqui~ para~ins, especially the "iso"
C10 paraffins and the mono- and bicyclic mono-terpenes, i.e., those o~ the hydrocarbon class, which include, for example, the terpinenes, limonenes and pinenes, and rnixture thereo~. ~ighly pre~ecred rnaterials of this latter type are d -limonene and the mixture of terpene hydrocarbons obtained from the essence of oranges (e.g.
cold-pressed orange terpenes and orange terpene oil phase ex fruit juice). Also use~ul are, for example, terpenes such as dipentene, alpha-pinene, beta-pinene and the mixture of terpene hydrocarbons expressed from lemons and grape-fruit.
Another preferred class of solvents are the C6-Cg alkyl aromatic hydrocarbons, especially the C6-Cg alkyl benzenes, in particular, octyl benzene. Short--chain alkyl benzenes (e.g. toluene) are not preferred herein due to toxicity and odor problems, and longer-chain alkyl benzenes have undesirable soil redeposition problQms.
especially when used to launder fabrics.
Still another preferred class of solvents are the olefins having a boiling point of a~ least about 100C.
The alpha-olefins have no~ been found to possess excellent cleaning properties and low, rather pleasant odors. The compounds l-decene and l-dodecene are especially preferred olefin solvents for laundry detergent use.
In a highly preferred mode, the relatively non-polar solvents, such as paraffin, olefin, terpene or alkyl benzene solvents mentioned above, are used in combination with a more polar solvent such as, for example, benzyl alcohol, n-hexanol, phthalic acid esters such as dimethyl-, diethyl--(preferred), dipropyl- or dibutyl~pththalate, or the "Carbitol" solvents such as Butyl Carbitol (trade mark for 2-(2-butoxyethoxy)ethanol) ~L23Q~3~

to provide broad-spectrum cleaning of a variety of polar and non-polar soils. Such mixtures will have a ratio of non--polar:polar solvent in the range of lO:l to l:lO.
preferably 5:1 to 1:5, and most preferably have a bit more non-polar than polar solvent, generally a ratio of 5:1 to 5:4, especially for fabric laundering.
The examples disclosed hereinafter describe various other solvents which can be used in the present compositions.
As will be seen from the following disclosure, various conventional detergent ingredients are used herein at conventional amounts and concentrations.
Importantly, in the formulation of li~uid detergents, the solvents herein can be used in combination with relatively high (15%-25%, and higher depending on solvent~
levels of fatty acid/soap, which provide an important detergency builder function, ~3L23~;34 Detersive Surfactants - The compositions of this invention will typically contain organic surface-active agents ~surfactants) to provide the usual cleaning benefits associated with the use of such materials.
Detersive surfactants useful herein include well-known synthetic anionic, nonionic, amphoteric and zwitterionic surfactants. Typical of these are the alkyl benzene sulfo-nates, alkyl- and alkylether sulfates, paraffin sulfonates, olefin sulfonates, alkoxylated (especially ethoxylated) al-cohols and alkyl phenols, amine oxides, ~-sulfonates of fatty acids and of fatty acid esters, and the like, which are well-known from the detergency art. In general, such detersive surfactants contain an alkyl group in the Cg-Cl8 range; the anionic detersive surfactants can be used in the form of their sodium, potassium or triethanolammonium salts but it is to be understood that the presence of magnesium cations in the compositions usually means that at least some portion of the anionic surfactant will be in the magnesium salt form; the nonionics generally contain from about 5 to about 17 ethylene oxide groups. U.S. Patents 4 111 855 and 3 995 669 contain detailed listings of such typical deter-sive surfactants. cll-cl6 alkyl benzene sulfonates, C12-C18 paraffin-sulfonates and alkyl sulfates, and the ethoxylated alcohols and alkyl phenols are especially preferred in the compositions of the present type.
The surfactant component can comprise as little as 1% of the compositions herein, but preferably the composi-tion~ will contain 1% to 40% , preferably 10% to 4~% , of sur-factant. Mixtures of the ethoxylated nonionics with anionics such as the alkyl benzene sulfonates, alkyl sulfates and paraffin sulfonates are preferred for through-the-wash cleansing of a broad spectrum of soils and stains from fabrics.
Such surfactants and mixes typically have ~LB s of 20 and above.

Polyamlnes - Polyamine materlals are optional ingredients in the present compositions by virtue of their ability to co-act with the solvent to remove the solid material that is present in many greasy stains (e.g., carbon black in motor oil stain; clay and color bodies in cosmetic stain). It is to be understood that the term "polyamines" as used herein represents generically the alkoxylated polyamines, both in their amine form and in their quaternarized form. Such materials can conveniently be represented as molecules of the empirical structures with repeating units:

t N - R t- Amine for~
x dlXQXy and - R -~ ~ Quaternarized I x form alkoxy wherein R is a hydrocarbyl group, usually of 2-6 carbon atoms; R may be a Cl-C20 hydrocarbon; the alkoxy groups are polyethoxy, polypropoxy, and the li~e, with polyethoxy having a degree of polymerization of 2-30, most preferably lO to 20; x is an integer of at least 2, preferably from

2-20, most preferably 3-5; and ~ is an anion such as halide or methylsulfate, resulting from the quaternization reaction. The anion X~ is of no particular consequence to performance of the polyamine in the present context, and is mentioned only for completeness in the above formula.
The most highly preferred polyamines for use herein are the so-called ethoxylated polyethylene imines, i.e., the polymerized reaction product of ethylene oxide with ethylene-imine, having the general formula:

~L~31~34 g N--CH2--CH2----~--x (E+O)y wherein x is an integer of 3 to 5 and y is an integer of 10 to 20.
Polyamines typically will comprise at least about 0.2% of the preferred comFositions herein, generally 0.5~-5%.
Other OFtional In~redients - The compositions herein can contain other ingredients which aid in their cleaning performance. For example, it is highly preferred that through-the-wash detergent o~npositions con-tain a detergent builder and/or metal ion sequestrant. Com~ounds classifiable and well-known in the art as detergent builders include the nitrilotriacetates, polycartoxylates, c;trates, water-soluble phosphates suc'n as tri-polyphosphate and sodium ortho- and pyro~
phosphates, silicates, and mixtures thereof. Metal ion sequestrants include all of the a~ove, plus materials like ethylenediaminetetra-acetate, the amino-polyphosphonates and phosphates (DEQUES~ and a wide variety of other poly-functional organic acids and salts too numerous to mention in detail here. See U.S. Patent 3 579.454 for typical examples of the use of such materials in various cleaning compositions. In general, the builder/sequestrant will comprise about 0.5~ to 15% of the composition. Citrate is one of the most ~referred builders since it is readily soluble in the aqueous phase of heavy-duty liquid detergent compositions. Such ingredients are also useful in hard-surface cleaners.
A source of magnesium ions can be used in the compositions, to assist grease removal. Besides magnesium hydroxide, water-soluble salts such as magnesium chloride, acetate, sulfate, and the like, can be used.
The laundry compositions herein also pre~erably contain enzymes to enhance their through-the-wash cleaning perfor-mance on a variety of soils and stains. Amylase and pro-tease enzymes suitable for use in detergents are well-known ~Z3~53~

in the art and in commercially available liquid and granular detergents. Commercial detersive enzymes (preferably a mixture of amylase and protease) typically function best at pH above about 7 and are typically used at levels of 0.001% to 2%, and higher, in the present compositions.
Ingredients such as propane diol and/or formate and calcium can be added to help stabilize the enzymes in well-known fashion, according to the desires of the formulator.
Moreover, the compositions herein can contain, in addition to ingredients already mentioned, various other optional ingredients typically used in commercial products to provide aesthetic- or additional product performance benefits.
Typical ingredients include pH regulants, perfumes, dyes, optical brighteners, soil suspending agents, hydrotopes and gel-control agents, freeze-thaw stabilizers, bactericides, preservatives, suds control agents and the like. Such ingredients typically comprise 0.1% - 10% of the formulations.
Water or water-alcohol (e.g., ethanol, isopropanol, etc.) mixtures are used as the carrier vehicle, and alkylated polysaccharides can be used to increase the stability and performanc~ characteristics of the compositions.

~ 230534 Inustrial App'ication .:-e Lo~ lowina e.~ampLes describe a variety of formulations ;;..lC'' can be ~re~ared in the manner of the present invention.
~e examDles are a;iven by wav of illustration and are not ntande~ ~o be li,T,iting of the scope of the invention. In .he polvamine-containing formulations listed, the terms "x"
and "y" are stated in parentheses to designate the degree of polymerization and degree of alkoxylation of the polyamine.
For some "polyamines", the designation R is also included, therebv denoting a quaternarized polyamine. For such auater-narized materials, the resulting anion X is of no consequence to cleaning performance, and is not designated.

..~e~y-n~y.li~i~ e~
Special attention is directed to highly preferred formula-tions which are particularly useful as heavy duty liquid detergents that are suitable for laundering all manner of fabrics in a typical home laundering operation.
The heavy duty liquid detergents disclosed hereinafter are formulated with a variety of detersive ingredients to provide excellent cleaning of a wide variety soils and stains, with particularly noteworthy benefits with regard to cosmetic and dirty motor oil stains.
It is to be understood that the following formulations are in the fonn of oil-in-water emulsions (wherein the sol-vent is considered the "oil" phase) and are substantially clear, homogeneous, stable microemulsions. Surprisingly, when used in a pre-treatment mode, the oil-in-water micro-emulsions herein are comparable in grease-cutting performance to water-in-oil emulsions, which have much higher concentra-tions of solvent. The compositions also exhibit excellent whiteness maintenance on cotton fabrics, apparently because the solvent reduces fatty acid soap build-up on fabric surfaces and the pH of the composition enhances enzyme cleaning performance. These performance advanta~es are particularly noti~ceable after multi-cycle washings.

~Z30534 The preparation of s-table, heavy-duty liq~id detergents in their preferred oil-in-water microemulsion ~orm iS
carried-out with attention being ~iven to the water carrier liquid, the use of Eatty acid/soap as a detergency builder/
emulslon stabll~zer ingredient and proper attention to pH regulation.

Fatty Acids and Soaps - Fatty acids ~uch as lauric, myristic, palmitic, stearic and oleic acids, and poly-unsat-urated fatty acids, as well as their water-soluble salts (i.e., "soaps") are employed in tlie present compositions to provide clear, homogeneous ~ormula-tions containing the solvent and water. Mixtures o fatty acids (or soaps) such as palm oil acids, coconut oil acids, and the lxke, in the Cl2-Cl8 carbon ~ai~ l~n~t~, can be used. ~'In general, the concentration of fatty acid (or soap~ is from 5 % to 50 ~, preferably 5 ~ to 35 ~, most preferably ln % to ~0 ~, and the weight ratio of fatty acid (or soap):solvent is generally in the range of 4:l to l:4, preferably 3:l to l:2. When using fatty soap, the potassium salt and sodium forms are preferred, but any convenient water-soluble salt may be used.
Apart from their function as microemulsion stabilizers, these fatty acid/soap materials provide an important deter-gency bui~lder function in the present compositions. However, it has now been discovered that when formulating oil-in-water microemulsion compositions at a pH greater than about 6.5, the presence of fatty acid/soap can actually destabilize the system. Means or overcQming this de-stabilization while maintaining a pH of 6,5 or aboYe in microemulsions containing builder levels of fatty acid/soap are disclosed in detail, here~nafte~.

Water - The liquid compositions herein may properly be characterized ~s "water-based", in contXast wi~th or~nic solvent-based cleaners known in ~he art.

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lZ~053A

SurprLsingly, water can inteLfere with the ability of solven~s to remove gre~sy stains from fabrics, For example, a fabric stai~ned w~th motor oil and dampened with ~,a,ter prior to tre~tment with a terpene solvent is not very well de-greased, if at all, By contrast, the present co~positions whereIn the solvents are microemulsi~ied in water are excellent greasy stain removers when used directly on dry or damp fabrics.
Apart ~rom water's obvious envi~ronmental ~nd safety pedigrees and lo~ cost as opposed to organic solvents, water-based heavy duty liquid detergents offer ease-of-for-mulation ad~antages with respect to Ingredients such as most detergency bui~lders, sani~tizers, chelants, soil-suspending agents, pH-control agents, and the l~ke, which are usually water-soluble.
Accordingly, the compositions hereIn exhibit the advantages of water-based for~ulation flexibility, together with the superior grease removal qualities of solvent-based compositions.
As will be described more fully hereinafter, the present compositions generally comprise from 10 % to 70 %, preferably 20 '~ to 50 ~ water. The weight ratio of water:solvent is generally 10:1 to 1:1, preferably 5:1 to 2:1.
pH/S*abilizer - As is well-known in the detergency arts, it is preferred for detergent compositions to be used in the near-neutral to alkaline pH range, i.e., pH 6.5, and above.
This is for a variety of reasons. For example, many soils are partly peptized or emulsified by alkalinity, itself. And, many commercially aYailable detersive enzymes (e,g,, the "alkaline protea,ses") function optimally in alkaline laundering liquors~
It has nDw been d~scovere,d tha,t stable ol~-in-water microemuls~on detergent compos,itions, ~hich co~pr~se builder leveis of fatty acid/s~a~p are. de-st,a,bilized ~hen the~r ",as-is" pH

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OS;~A

lS ad~usted to about 6.5, and above. (The pH where instabi-lity is noted may vary slightly with the actual grease-cutting sol~en~ ~IsQ~l in the mi.cruelllulsio~, i-ts lev~l, and the chain length and de-gree of unsaturation of the fatty acid.) This prob]em is especially acute with substantially non-polar, hydrocarbon grease-cutting solvents, e.g., alkyl benzenes and alpha-oleflns~
and liquid paraffin solvents.
The stability problem seems to arise by virtue of the fatty acid, which has an HLB of approximately 2, being con-verted almost entirely to soap, with an HLB of about 20, over a very narrow pH range, roughly 6.5-6.9. Thus, since the fatty acid is present in substantial amounts (ca. 5~, and higher) this major shift in HLB upsets the HLB of the emulsification system and results in de-stabilization.
It is to be understood that formulation stability could theoretically be achieved ~y proper selection of surfactants (discussed hereinafter) with low HLB's. For example, nonionic surfactants such as Cl4 15 alcohols with low ethoxylate numbers (1-3) could be used. However, such low HLB surfactants do not function well as detersive sur-factants, and the object herein is not only to provide stable mlcr~emulsions, but also good pre-treat and through-the-wash detergency.
It has now been found that by either increasing the ionic strength of the aqueous phase, or by adding solvent-soluble ingredients with low HLB's, which increase solvent polarity, to the solvent phase, or by us~ both means conjointly, the microemulsion is stabilizec.In particular, adding water-soluble, high ionic strength ingredients such as, for example, formate, sulfate, citrate, and the like, increases stability. By contrast, adding water-soluble, low ionic strength materials such as ethanol has no stabilizing effect.

)534 Also, adding slightly polar but solvent-soluble ingredients with low HLB's such as n-hexanol, benzyl alcohol, diethyl phthalate and the like increases stability.
Conjointly adding the ionic strength ingredients and the solvent-soluble ingredients further enchances stability.
Of course, the formulator can select ingredients with a view towards not only increasing microemulsion stability, but also providing optimal cleaning benefits. For example, one can choose citrate as an ionic strength agent which also has detergency builder properties, formate as an ionic strength agent which also stabilizes detergent enzymes, and n-hexanol or benzyl alcohol or diethyl phthalate as a low HLB ingredient which also serves a useful co-solvent cleaning function.
The amount of ionic strength or low e.g. (2-5) HLB
solvent-soluble ingredients, or both, used in the compositions will depend somewhat on the pH desired, the concentration of fatty acid, the level of grease-cutting solvent, the composition of the detersive surfactant system, and the like. Microemulsion stability can be monitored rather simply since the true microemulsions are clear, but turn hazy and non-homogeneous,with eventual phase separation at the point of instability. Moreover, true oil-in-water microemulsions turn hazy when diluted with water, whereas water-in-oil emulsions tend to gel, and micellar oil-plus-water systems remain clear.
With regard to pH adjustments in the comPositions u~ to a~out pY.6.5-6.6, any of the well-known base materials can be used, for example, triethanolamine, alkali metal hydroxide and the like.
Potassium hydroxide is preferred over sodium hydroxide, inasmuch as the ease of formulation of stable systems is increased substantially by the potassium cation.
Nitrogen-functional Stabllizers/pH Regulants - It has now been discovered that various alkyl and cyclo-alkyl amines, quaternary ammonium compounds and amine oxides constitute a highly preferred class of pH regulants and stabilizers in the oil-in-water microemulsion detergent compositions of the ~230~i3~

present type. Apparently, such materials may somehow associate with the fatty acid or anionic surfactants to form a complex which stabilizes the microemulsified oil (solvent). While the nitrogen functional compounds do not boost the pH very much towards the alkaline range (only several tenths of a pH unit, measured on the product formul-ated "as is") the resulting boost in detergency performance is substantial.
Dioctyl dimethyl ammonium chloride is a highly preferred quaternary used herein as a pH-regulant, but there can also be mentioned the following quaternaries in increasing order of preference of use : coconut trimethyl ammonium chloride (6.66) ; di-coconut dimethyl ammonium chloride (6.84) ; coconut benzyl dimethyl ammonium chloride (6.84) ; and dihexyl dimethyl ammonium chloride (6.89). The numbers in parentheses denote the pH achievable by adding the respective quaternaries to a liquid oil-in-water microemulsion containing fatty acid and formulated at an "as is" pH of 6.5. For the preferred dioctyl dimethyl ammonium chloride, the pH figure is 6.94.
Suitable alkyl and cyclo-alkyl amines-useful herein (with attendant pH's) include : coconutalkyl diethanol amine (6.65) ; coconutalkyl dimethyl amine (6.75) ;
trioctyl amine (7.0) ; and cyclohexyl amine (7.5).
Suitable amine oxides herein include coconutalkyl dimethylamine oxide (6.7) and dioctyl methylamine oxide (est.> 7).
It is to be understood that the foregoing nitrogen compounds are added to the compositions until the desired pH is obtained. To achieve the pH listed,from 0.5~ to 5~ -of the compounds are typically used in the compositions. Cyclo-hexyl amine (1-5~) is most preferred for use herein.
The highly preferred, fully-formulated compositons herein are in liquid form, which can be prepared by simply blending the essential and optional ingredients in the aqueous carrier. Microemulsion stability can be estimated visually by watching for phase separation, or can be monitored more quantitatively by standard turbidometric /~
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techniques.
In one process aspect, the compositions can be used to pre-treat soiled fabrics by rubbing a few milliliters of the composition directly onto and into the soiled 5 area, followed by laundering, in standard fashion. In a through-the-wash mode, the compositions are typically used at a concentration of at least 500 ppm, preferably O.l % to l.5 % in an aqueous laundry bath at p~ 6.5 and above to launder fabrics. The laundering can be carried out over the range from 5 C to the boil, with excellent results.
For use on hard surfaces, as rug cleaners, and as general-purpose cleaners, such compositions are usually diluted with water.
The following ~xamples illustrate the practice of this invention, but are not intended to be limiting thereof.

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lZ30534 EXAMPLE I

INGREDIENT % By Weight Cll 8 Alkyl Benzene Sulphonic Acid 10.0 14/15 Alkyl Ethoxylate (E0 7) 10.9 Coconut Fatty Acid (Broad Cut) 18.2 Oleic Acid 2.3 Monomethyl Ethanolamine 5.8 n-Octyl Benzene 9.1 Ethanol (95 %) 2.7 DEQUEST (50 %)1 1.09 Formic Acid 0.18 K3 Citrate.H2O (63.5% in H2O) 4-4 CaC12.2H20 0.05 Maxatase Enzyme (Protease) 0.73 Termamyl Enzyme (amylase) 0.10 Ethoxylated Polyamine 2. 1.73 Perfume/Optical Brightener/Dye 0.5 Water Balance Product pH "as is" 6.6 Dioctyl Dimethyl Ammonium Chloride to pH 6.94 1. Diethylene triamine pentamethylenephosphonic acid.
2, Tetraethylene Pentamine 105 EO units/molecule The composition of Example I is a stable, oil-in-water microemulsion suitable for use as a laundry detergent.

~230~;34 EX~MPLE II
-The composition of Example I is modified by replacing the n-octyl benzene by the same amount (9.1 % total formulation) of l-decene. Product pH "as is" : 6.6. The pH is adjusted to 6.94 with dioctyl dimethyl ammonium chloride.
EXAMPLE III
The composition of Example I is modified by replacing the n-octyl benzene by any of the following solvent mixtures (percentages of total formulation being specified in parentheses):
l-Decene (6.1 %) Diethylphthalate (3.0 %); l-Dodecene (7.3 %)/
Benzyl alcohol (1.8 %) ; n-octyl benzene (6.2 %)/Diethylphthalate (2.9 %) ; octyl benzene (6.0 %)/Butyl Carbitol (3.1 %).
Product pH's as is : 6.6 In each instance, product pH is adjusted to 6.9 with dioctyl dimethyl ammonium chloride.

EXAMPLE IV
The compositions of Example III comprising solvent mixtures are adjusted to pH 7.0 with trioctyl amine and to pH 7.1 with dioctyl methylamine oxide, respectively, and stable, microemulsions are secured.
As can be seen from the foregoing, the present invention provides effective means whereby microemulsions comprising fatty acid~soap at high levels can be adjusted to a preferred pH range of 6.65 to 7.3 using mono- and di- C6-C18 tri- and dimethyl ammonium salts ; or C4-C8 alkyl or cycloalkyl amines;
or mono- and di- C6C18 alkyl dimethyl and monomethyl amine oxides.
Further examples of the compositions herein are as follows.
EXAMPLE V
The composition of Example I is modified by replacing the Ethoxylated Polyamine with any of the following alkoxylated polyamines A, ~ or C, having the general formula disclosed hereinbefore.
Iq lZ30S34 Polyamine A : x = 2; y = 2; R = ethylene; aIkoxy = ethoxy Polyamine B : x = 20; y = 30; R = propylene;alkoxy = propoxy Polyamine C : x = 3, y = 15; R = ethylene; alkoxy = ethoxy; R' = butyl The alkoxylated polyamines contribute to the clay soil removal performance of the compositions.
EXAMPLE VI
The pH of the compositions of Example V are adjusted to 7.3 with addition of 5 parts (by weight of composition) of cyclohexyl amine.
EXAMPLE VII
The composition of example II is modified by replacing the l-Decene by a mix of 6 % diethylphthalate/2 % liquid iso-paraffin/2 % orange terpene . The product is stable at pH 6.94 when dioctyl dimethyl ammonium chloride is present at a level of about 2.5 %.

Another preferred olefin solvent herein by virtue of its relatively low odor is the so-called "P-4" polymer, available from a number of petrochemical suppliers to the detergent industry as a raw material for branched alkyl benzene. P-4 is an isomer mix of the condensation product of 4 moles of propylene, i.e., Cl2 branched olefins.
P-4 is non-polar, and is preferably used in combination with a polar solvent such as benzyl alcohol, diethylphthate, Butyl Carbitol or the like, Other useful polar solvents herein include the "Cellosolves"
e.g. alkoxyl alkanols such as 2-butoxyethanol ; C6-C12 alkanols lincluding benzyl alcohol) such as dodecanol, phenethyl alcohol, diglycolether acetates, and the like.

EXAMPLE VI I I
Other solvent mixtures useLul herein are as follows.

Composition Inqredient Percent A Octyl benzene 70%
Diethyl phthalate 30%
B '-Decene 70%
Diethyl phthalate 30%
C Octyl benzene 80%
Benzyl alcohol 20%
D n-Octyl benzene 90%
Butyl carbitol 10%
E l-Decene 65%
Dibutyl phthalate 35%
F n-Octyl benzene 30%
l-Decene 40%
Benzyl alcohol 10%
Butyl carbitol 20%
G l-Decene 80%
n-Hexanol 20%
H l-Decene 60%
Diethyl phthalate 40%
I l-Dodecene 80%
Hexyl cellosolve 20%
J Mixed 1:1 nonyl/hexyl benzene 35%
2-Dodecene 35%
Dimethyl phthalate 30%
In a preferred method of use aspect, the compositions herein are used in an aqueous laundering liquor, preferably at a liquor pH of 6.5-8.0 tmeasured as 1% of composition in water) to launder fabrics. Excellent cleaning is attained by agitating fabrics in such liquors especially at this preferred in-use pH range.

-- ~ 2 --E_MPLE IX
A highly preferred liquid laundry detergent by virtue of the low odor properties o~ its grease removal solvent system, its stability in microemulsion form, and its enzymatic cleaning activity (by virtue of its pH) is as follows.

Inqredient Parts by Weiqht Alkyl(Cll 8)benzene sulfonic acid 11.0 Alkyl(cl4/l5)ethoxylate (E07) 12.0 Topped whole cut coconut fatty acid (1) 20.5 C10~ soparaffins 4 0 Diethyl phthalate 6.0 Cyclohexylamine 2.0 Monomethyl ethanolamine (2)4.3 Pota~sium citrate monohydrate (63.5% in water) 2.4 Dequest 2060 S 1.7 Ethoxylated polyamine (x=5, y=15) 1.5 Ethanol 3.0 Potassium hydroxide (50% in water) (2) 3.0 Formic acid 0.2 CaC12 2H2O 0.05 Optical brightener (anionic) 0.18 Maxatase enzyme (3) 0.71 Termamyl 300L enzyme (4) 0.10 Dye 20 ppm Perfume 0 5 Water up to 110 parts Product pH 6.9 (1) Chain length mixture: Clo(5%) Clz(55%) C~(22~) C18(2~) oleic(lo%) (2) To adjust pH to 6.6

(3) From KNGS

(4) From NOVO

~30534 The composition of Example IX is used in an aqueous laundry bath at a concentration of 100ml/10 liters and provides an in-use pH of about 7.2 (varies with water hardness).
As can be seen from the foregoing, the primary amines are preferred pH-adjusting agents herein. In general, the C4-C18 alkyl amines are used, since the lower molecular weight amines tend to be excessively malodorous. Other examples of amines useful herein include dibutyl- and di-isobutyl amine. For typical use in detergent compositions intended for home-use, amines having a boiling point above 100C are preferred.
Product "as is" pH is measured at ambient (23C) temperature using a commercial pH meter. The electrode is immersed in the product and the meter is allowed to stabilize before reading.

Claims (13)

Claims:

1. A detergent composition in the form of a liquid oil-in-water microemulsion, wherein said oil is one or more non-polar or polar "grease-removal" solvents, said composition comprising from 10% to 70% water; from 5% to 20% grease removal solvent or solvent mixture; from 5% to 35% fatty acid or fatty acid soap mixture; from 1% to 40%
detersive surfactant, as well as optional detersive ingre-dients, said composition comprising a sufficient quantity of an amine, a quaternary ammonium salt or an amine oxide to provide a pH of said composition (undiluted) above 6.5.

2. A composition according to claim 1 wherein the amine is selected from alkyl or cyclo-alkyl amines and the pH is in the range of 6.65 to 7.5.

3. A composition according to claim 2 wherein the amine is selected from coconut diethanol amine; coconut alkyl dimethyl amine; trioctyl amine; dibutyl amine; di-isobutyl amine and cyclohexyl amine.

4. A composition according to claim 1 wherein the quaternary ammonium salt is selected from mono- and di-C8-C18 tri- and di-methyl ammonium salts.

5. A composition according to claim 4 wherein the quaternary ammonium salt is selected from coconutalkyl trimethyl ammonium chloride, dicoconutalkyl dimethyl am-monium chloride, dihexyl dimethyl ammonium chloride and dioctyl dimethyl ammonium chloride.

6. A composition according to claim 1 wherein the amine oxide is selected from the mono- and di-C6-C18 alkyl dimethyl and monomethyl amine oxides.

7. A composition according to claim 6 wherein the amine oxide is selected from coconutalkyl dimethyl amine oxide and dioctyl methyl amine oxide.

8. A composition according to claim 1 wherein the detersive surfactant is selected from alkyl benzene sul-fonates, paraffin sulfonates alkyl sulfates, ethoxylated alcohols or alkyl phenols, or mixtures thereof.

9. A composition according to claim 1 wherein the solvent is selected from: C6-C9 alkyl benezenes; liquid olefins having a boiling point of at least 100°C; terpene hydrocarbons, C6-C12 alcohols, paraffins, and mixtures thereof.

10. A composition according to claim 1 wherein the solvent is selected from a mixture of:
a) n-octyl benzene, 1-decene, 1-dodene, liquid C10 iso-paraffin or terpene; and b) benzyl alcohol, diethylphthalate, dibutyl-phthalate, or 2-(2-butoxyethoxy)ethanol at a weight ratio of (a) to (b) of 10:1 to 1:10.

11. A composition according to claim 10 which contains 0.5%-5% cyclohexylamine.

12. A composition according to claim 1 which also contains a detersive enzyme.

13. A method of laundering fabrics by agitating fabrics in an aqueous liquor containing a composition according to claim 1 at a liquor pH of 6.5-8Ø