EP0222557B1

EP0222557B1 - Liquid detergent composition

Info

Publication number: EP0222557B1
Application number: EP19860308453
Authority: EP
Inventors: Eugene Joseph Pancheri; Young Sik Oh; Rodney Mahlon Wise
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1985-10-31
Filing date: 1986-10-30
Publication date: 1993-10-13
Anticipated expiration: 2006-10-30
Also published as: DE3689165T2; MX165143B; FI87086C; AU589225B2; FI87086B; EP0222557A2; CA1299962C; DK522786A; EP0222557A3; FI864424A0; DE3689165D1; AU6454286A; DK522786D0; FI864424A

Abstract

High sudsing liquid detergent compositions contain anionic surfactant and polymeric surfactant which contains ether linkages, the anionic surfactant forming stable complexes with the polymeric surfactant for improved grease handling.

Description

Technical Field and Background Art

The invention relates to aqueous high sudsing liquid detergent compositions containing specified amounts and types of polymeric surfactants especially useful in the washing of tableware, kitchenware and other hard surfaces.
Compositions incorporating polymeric surfactants are known in the art.
For example EP-A-0105556 discloses an aqueous liquid dishwashing detergent composition containing a mixture of anionic, alkoxylated nonionic and alkyl polysaccharide surfactants that provide enhanced drainage of rinse water from articles washed by the compositions. Examples of suitable nonionic surfactants include the condensate of ethylene oxide, propylene oxide and a compound containing hydroxyl or amine groups onto which the alkylene oxides can be polymerised.
EP-A-0083223 also discloses detergent compositions incorporating alkylene oxide homo- and co-polymers for grease and oil emulsification.
EP-A-0024711 discloses concentrated aqueous anionic surfactant solutions incorporating the mono- and/or di-sulfates of poly C₂-C₃ alkylene glycols of MW >600 as viscosity modifiers, optionally together with unsulfated C₂-C₃ polyalkylene glycols of MW >1500.
The compositions of this invention have superior ability to handle grease.
The performance of a detergent composition for cleaning tableware and kitchen utensils is evaluated by its ability to handle grease. The detergent solution should readily remove grease and minimize its redeposition.
There is continuing need for improved compositions and methods which can be employed during dishwashing operations to improve the appearance of kitchen utensils and articles. Such compositions and methods should provide improved removal of grease in conventional dishwashing soil removal operations while maintaining the sudsing attributes of an acceptable dishwashing detergent composition.

Summary of the Invention

According to the present invention there is provided a high sudsing liquid detergent composition with enhanced grease handling ability containing by weight:

(a) from 5% to 50% anionic surfactant;
(b) from 0.1% to 10% of polymeric surfactant containing polymerised ethylene oxide and/or propylene oxide groups, said polymeric surfactant having a molecular weight of from 400 to 60,000;
(c) from 0% to 10% of a suds stabilizing nonionic surfactant selected from fatty acid amides, trialkyl amine oxides and mixtures thereof;
(d) from 0% to 10% of a detergency builder selected from inorganic phosphates, inorganic polyphosphates, inorganic silicates, inorganic carbonates, organic carboxylates, organic phosphonates, and mixtures thereof;
(e) from 0% to 15% of an alkanol containing from one to six carbon atoms; and
(f) from 20% to 90% water,

_n

_m

_y

i) alkylene groups containing from one to 18 carbon atoms,
ii) poly (hydroxyalkylene oxide) groups wherein each alkylene group has from one to six hydroxy groups and contains from three to eight carbon atoms and there are from two to fifty hydroxy alkylene oxide groups and from two to fifty hydroxy groups,
iii) (=NR²N=), and
(iv) =N(̵R²NH)̵_x,

_x

_y

_n

_z

Dishware, glassware, and other tableware and kitchenware are washed in water solutions of the detergent composition, generally at a weight concentration of from 0.05% to 0.4% of the composition in water at a temperature of from 15.6°C (60°F) to 48.9°C (120°F).

Detailed Description of the Invention

The liquid detergent compositions of the present invention contain two essential components:

(a) anionic surfactant which when there are no betaine surfactants or magnesium ions present is a C₁₀-C₂₀ alkylpolyethoxylate sulfate containing an average of from 0.25 to 10 ethoxy groups per molecule, said average being computed herein by treating any alkyl sulfate surfactant as an alkylpolyethoxylate sulfate containing 0 ethoxy groups, to provide good sudsing, and preferably a low interfacial tension; and
(b) the polymeric surfactant, which improves grease handling.

Optional ingredients can be added to provide various performance and aesthetic characteristics.

Anionic Surfactant

The compositions of this invention contain from 5% to 50% by weight of an anionic surfactant or mixtures thereof preferably comprising at least 5%, more preferably at least 8%, and most preferably more than 10% of an alkyl polyethoxylate (polyethylene oxide) sulfate having from 10 to 20, preferably from 10 to 16 carbon atoms in the alkyl group and containing from $\frac{1}{4}$
to 10, preferably from 1 to 8, most preferably from 1 to 6 ethoxy groups on the average. Preferred compositions contain from 20% to 40% of anionic surfactant by weight.
Most anionic detergents can be broadly described as the water-soluble salts, particularly the alkali metal, alkaline earth metal, ammonium or amine salts, of organic sulfuric reaction products having in their molecular structure an alkyl radical containing from 8 to 22 carbon atoms and a radical selected from the group consisting of sulfonic acid and sulfuric acid ester radicals. Included in the term "alkyl" is the alkyl portion of acyl radicals. Examples of the anionic synthetic detergents which can form the surfactant component of the compositions of the present invention are the salts of compatible cations, e.g. sodium, ammonium, monoethanolammonium, diethanolammonium, triethanolammonium, potassium and/or, especially, magnesium cations with: alkyl sulfates, especially those obtained by sulfating the higher alcohols (C₈-C₁₈ carbon atoms), alkyl benzene, or alkyl toluene, sulfonates, in which the alkyl group contains from 9 to 15 carbon atoms, the alkyl radical being either a straight or branched aliphatic chain; paraffin sulfonates or olefin sulfonates in which the alkyl or alkenyl group contains from 10 to 20 carbon atoms; sodium C₁₀₋₂₀ alkyl glyceryl ether sulfonates, especially those ethers of alcohols derived from tallow and coconut oil; coconut oil fatty acid monoglyceride sulfates and sulfonates; alkylphenolpolyethylene oxide ether sulfates with from 1 to 10 units of ethylene oxide per molecule on the average in which the alkyl radicals contain from 8 to 12 carbon atoms; the reaction products of fatty acids esterified with isethionic acid where, for example, the fatty acids are derived from coconut oil; fatty acid amides of a methyl tauride in which the fatty acids, for example, are derived from coconut oil; and beta-acetoxy- or beta-acetamido-alkanesulfonates where the alkane has from 8 to 22 carbon atoms.
Specific examples of alkyl sulfate salts which can be employed in the instant detergent compositions include sodium, potassium, ammonium, monoethanolammonium, diethanolammonium, triethanolammonium, and magnesium: lauryl sulfates, stearyl sulfates, palmityl sulfates, decyl sulfates, myristyl sulfates, tallow alkyl sulfates, coconut alkyl sulfates, C₁₂₋₁₅ alkyl sulfates and mixtures of these surfactants. Preferred alkyl sulfates include the C₁₂₋₁₅ alkyl sulfates.
Suitable alkylbenzene, or alkyltoluene, sulfonates include the alkali metal (lithium, sodium, and/or potassium), alkaline earth (preferably magnesium), ammonium and for alkanolammonium salts of straight, or branched-chain, alkylbenzene, or alkyltoluene, sulfonic acids. Alkylbenzene sulfonic acids useful as precursors for these surfactants include decyl benzene sulfonic acid, undecyl benzene sulfonic acid, dodecyl benzene sulfonic acid, tridecyl benzene sulfonic acid, tetrapropylene benzene sulfonic acid and mixtures thereof. Preferred sulfonic acids as precursors of the alkyl-benzene sulfonates useful for compositions herein are those in which the alkyl chain is linear and averages 11 to 13 carbon atoms in length.
The preferred anionic surfactants herein, which are essential if there are no, e.g., magnesium ions or betaine surfactant present, are alkylpolyethoxylate sulfates having the formula RO(C₂H₄O)_xSO₃M wherein R is alkyl of from 10 to 20 carbon atoms, x is from 1/4 to ten on the average, treating alkyl sulfates as if they had 0 ethoxy groups, preferably from $\frac{1}{2}$
to eight, most preferably from one to six, and M is a water-soluble compatible cation such as those disclosed hereinbefore. The alkylpolyethoxylate sulfates useful in the present invention are sulfates of condensation products of ethylene oxide and monohydric alcohols having from 10 to 20 carbon atoms. Preferably, R has 10 to 16 carbon atoms. The alcohols can be derived from natural fats, e.g., coconut oil or tallow, or can be synthetic. Such alcohols can be reacted with from $\frac{1}{2}$
to 20, especially from one to 14, and more especially from one to eight, molar proportions of ethylene oxide and the resulting mixture of molecular species is sulfated and neutralized.
There should be more than 10%, preferably more than 15% of such molecules containing one to 10 ethoxylate groups calculated as a percentage of the total anionic surfactant in the composition. When these molecules are mixed with alkyl sulfates which are treated as containing 0 ethoxylate groups, the computed average degree of ethoxylation should be more than 0.25, preferably more than 0.6. One can use a similar approach in computing the minimum desired amount of the alkyl polyethoxylate sulfate which should be present when admixed with any anionic surfactant. E.g. the other anionic surfactant can be treated as if it were an alkyl sulfate to compute the average degree of ethoxylation.
Specific examples of alkylpolyethoxylate sulfates of the present invention are sodium coconut alkylpolyethoxylate (3) ether sulfate, magnesium C₁₂₋₁₅ alkylpolyethoxylate (3) ether sulfate, and sodium tallow alkylpolyethoxylate (6) ether sulfate. A particularly preferred example is a water soluble, e.g. magnesium, C₁₂₋₁₃ alkylpolyethoxylate (1) ether sulfate. Preferred alkyl polyethoxylate sulfates are those comprising a mixture of individual compounds, said mixture having an average alkyl chain length of from 10 to 16 carbon atoms and an average degree of ethoxylation of from 1 to 8 moles of ethylene oxide.
For use in completely soft water, the compositions should contain magnesium ions, and/or at least 10%, preferably at least 15% by weight of the anionic surfactant, of the preferred alkyl polyethoxylate sulfates described hereinbefore. It is preferred that the compositions of this invention, including those that contain the preferred alkylpolyethoxylate sulfates, also contain magnesium and/or calcium ions, most preferably magnesium ions, to act as cations for a portion of the anionic surfactant. If the composition is to be used primarily in water containing more than 0.17 ppm Ca++ of hardness, added magnesium may not be essential. In use, from 10% to 100%, preferably from 20% to 90%, of the anionic surfactant should be the magnesium salt.
The formulation of anionic surfactant systems that will reduce the interfacial tension is well within the skill of the typical detergent formulator. For the purposes of this invention, the surfactant system minus the polymeric surfactant should preferably reduce the interfacial tension to below 0.25 Pa.cm, preferably below 0.2 Pa.cm , against triolein at a concentration of 0.2% and a temperature of 115°F (46°C) in a spinning drop Tensiometer. Interfacial tension is lowered by any detergent surfactant, but the efficiency can be improved by selection of surfactants which have longer alkyl chain lengths, use of cations such as magnesium which minimize charge effects when anionic surfactants are used, and use of anionic surfactants combined with cosurfactants like trialkylamine oxides which form complexes with the anionic surfactant. A more complete discussion of such effects can be found in Milton J. Rosen, Surfactants and Interfacial Phenomena, 149-173 (1978).

The Polymeric Surfactant

The compositions of the present invention contain from 0.1% to 10%, preferably from 1/2% to 4%, and most preferably from 1/2% to 2%, of the polymeric surfactant described generically hereinbefore and discussed in detail hereinafter.
The polymeric surfactant can be a compound according to any one of the following formulae:

1) [R¹(̵R²O)̵_n(̵R³O)̵_m]_y[R⁴]

wherein each R¹ is hydrogen, each R² or R³ is an alkylene group containing from two to six carbon atoms with no more than 90% of said molecule comprising R² and R³ groups containing two carbon atoms; wherein R⁴ is selected from alkylene groups containing from one to 18 carbon atoms, polyhydroxyalkylene oxide groups wherein each alkylene group has from one to six hydroxy groups and contains from three to eight carbon atoms and there are from two to 50 hydroxyalkylene oxide groups and from two to about 50 hydroxy groups, (=NR²N=) and =N(̵R²NH)̵_x;
wherein n is from 0 to 500, m is from 0 to 500, n + m is from 5 to 1000, x is from 2 to 50, and y is from one to 50 and equal to the valences of R⁴; wherein the molecular weight is from 400 to 60,000; and wherein the (R²O) and the (R³O) groups are interchangeable;

where: -
R¹ is H, or CH₃, or CH₃(CH₂)_n, or unsaturated analogues thereof
where:
n is 1-17
x,y is 2-500
R² is -O(CH₂)̵_z or unsaturated analogues of these where z is 1-18, the percentage of (̵OCH₂CH₂)̵ groups in the molecule being less than 90%;

where
X=8, Y=4
X=8, Y=14
X=17, Y=10

where
X=16, Y=2.75
X=7.5, Y=2.75
While not wishing to be bound by theory, it is believed that the polymeric surfactant functions by forming complexes with the hydrophilic portions of the anionic surfactants, thereby minimizing the ability of the anionic surfactants to leave a micelle or other interfacial region once formed. Long terminal hydrocarbons pull the polymer into any oil phase, thereby minimizing the number of anionic surfactant molecules that are stabilized. Similarly, if the hydrophilic portion of the molecule is too hydrophilic, the molecule is pulled into the aqueous phase too far. The molecule should be balanced between hydrophobicity and hydrophilicity and have enough ether and/or amine linkages spread throughout the structure to complex the anionic surfactant. The anionic surfactant also must be one that will form the complex. Magnesium cations, ether linkages, and amine or ammonium groups form stable complexes with the polymeric surfactants.
Preferably the surfactant contains a hydrophilic group comprising polyethylene oxide and/or ethyleneimine groups containing from 1 to 500 ethylene oxide and/or ethyleneimine derived moieties. The polymeric surfactant also contains at least one hydrophobic group, preferably comprising polyalkylene oxide groups wherein the alkylene contains from three to six, most preferably three, carbon atoms and the molecular weight is from 400 to 60,000. The alkylene groups containing from 7 to 18, preferably from 10 to 18, carbon atoms can also be used, abut preferably only short chain relatively nonoleophilic alkyl or acyl groups containing less than ten carbon atoms are pendant on the polymeric surfactant.
Preferred surfactants are block copolymers comprising one or more groups that are hydrophilic and which contain mostly ethylene oxide groups and one or more hydrophobic groups which contain mostly propylene oxide groups attached to the residue of a compound that contained one or more hydroxy or amine groups onto which the respective alkylene oxides were polymerized, said polymers having molecular weights of from 400 to 60,000, an ethylene oxide content of from 10% to 90% by weight and a propylene oxide content of from 10% to 90% by weight.
Preferred surfactants are those in which propylene oxide is condensed with an amine, especially ethylenediamine to provide a hydrophobic base having a molecular weight of from 350 to 55,000, preferably from 500 to 40,000. This hydrophobic base is then condensed with ethylene oxide to provide from 10% to 90%, preferably from 20% to 80% ethylene oxide. Reverse structures in which the ethylene oxide is condensed first are also desirable. These structures are especially easy to formulate into desirable single phase liquid compositions.
Similar structures in which the ethylediamine is replaced by a polyol, especially propylene glycol, or glycerine, or condensation products of glycerine, are also desirable.
In similar compositions, the polypropylene glycol portion can be replaced by an alkyl, or alkylene group containing from 5 to 18, preferably from 8 to 16 carbon atoms.

Suds Stabilizing Nonionic Surfactant

The compositions of this invention contain from 0% to 10%, preferably from 1% to 8%, of suds stabilizing nonionic surfactant or mixtures thereof.
Suds stabilizing nonionic surfactants operable in the instant compositions are of two basic types: fatty acid amides and the trialkyl amine oxide semi-polar nonionics.
The amide type of nonionic surface active agent includes the ammonia, monoethanol and diethanol amides of fatty acids having an acyl moiety of from 8 to 18 carbon atoms and represented by the general formula:

R¹-CO-N(H)_m(R²OH)_2-m

wherein R₁ is a saturated or unsaturated, aliphatic hydrocarbon radical having from 7 to 21, preferably from 11 to 17 carbon atoms; R² represents a methylene or ethylene group; and m is 1 or 2. Specific examples of said amides are coconut fatty acid monoethanol amide and dodecyl fatty acid diethanol amide. These acyl moieties may be derived from naturally occurring glycerides e.g., coconut oil, palm oil, soybean oil and tallow, but can be derived synthetically, e.g., by the oxidation of petroleum, or hydrogenation of carbon monoxide by the Fischer-Tropsch process. The monoethanol amides and diethanolamides of C₁₂₋₁₄ fatty acids are preferred.
Amine oxide semi-polar nonionic surface active agents comprise compounds and mixtures of compounds having the formula:

wherein R¹ is an alkyl, 2-hydroxyalkyl, 3-hydroxyalkyl, or 3-alkoxy-2-hydroxypropyl radical in which the alkyl and alkoxy, respectively, contain from 8 to 18 carbon atoms, R² and R³ are each a methyl, ethyl, propyl, isopropyl, 2-hydroxyethyl, 2-hydroxypropyl, or 3-hydroxypropyl radical and n is from 0 to 10. Particularly preferred are amine oxides of the formula:

wherein R¹ is a C₁₀₋₁₄ alkyl and R² and R³ are methyl or ethyl.
The preferred sudsing characteristics of the compositions of the invention are those which will provide the user of the product with an indication of cleaning potential in a dishwashing solution. Soils encountered in dishwashing act as suds depressants and the presence or absence of suds from the surface of a dishwashing solution is a convenient guide to product usage. Mixtures of anionic surfactants and suds stabilizing nonionic surfactants are utilized in the compositions of the invention because of their high sudsing characteristics, their suds stability in the presence of food soils and their ability to indicate accurately an adequate level of product usage in the presence of soil.
In preferred embodiments of the invention, the ratio of anionic surfactants to suds stabilizing nonionic surfactants in the composition will be in a molar ratio of from 11:1 to 1:1, and more preferably from 8:1 to 3:1.

Other Optional Surfactants

The compositions of the invention can desirably contain optional surfactants, especially ampholytic and/or zwitterionic surfactants. However, when the level of anionic surfactant is less than 20%, the composition should not contain any substantial amount of conventional nonionic surfactant, e.g., an alkylpolyethoxylate, in addition to the polymeric surfactant. Large amounts of conventional nonionic surfactants, e.g., more than about three or four percent, tend to harm the sudsing ability of the composition.
When larger amounts ( > 20%) of anionic surfactants are present it is sometimes desirable to have a low level, up to 5%, of conventional nonionic surfactants; "conventional" nonionic surfactants are, e.g., C₈₋₁₈ alkyl polyethoxylates (4-15) or C₈₋₁₅ alkyl phenol polyethoxylates (4-15).
Ampholytlc surfactants can be broadly described as derivatives of aliphatic amines which contain a long chain of 8 to 18 carbon atoms and an anionic water-solubilizing group, e.g. carboxylate, sulfonate or sulfate. Examples of compounds falling within this definition are sodium-3-dodecylamino propane sulfonate, and dodecyl dimethylammonium hexanoate.
Zwitterionic surface active agents operable in the instant composition are broadly described as internally-neutralized derivatives of aliphatic quaternary ammonium and phosphonium, and tertiary sulfonium compounds in which the aliphatic radical can be straight chain or branched, and wherein one of the aliphatic substituents contains from 8 to 18 carbon atoms and one contains an anionic water solubilizing group, e.g., carboxy, sulfo, sulfato, phosphato, or phosphono.
Highly preferred are betaine detergent surfactants which synergistically interact with the polymeric surfactant to provide improved grease handling.

The Betaine Detergent Surfactant

The betaine detergent surfactant has the general formula:

wherein R is a hydrophobic group selected from alkyl groups containing from 10 to 22 carbon atoms, preferably from 12 to 18 carbon atoms, alkyl aryl and aryl alkyl groups containing a similar number of carbon atoms with a benzene ring being treated as equivalent to 2 carbon atoms, and similar structures interrupted by amido or ether linkages; each R⁶ is an alkyl group containing from one to 3 carbon atoms; and R⁷ is an alkylene group containing from one to 6 carbon atoms.
Examples of preferred betaines are dodecylamidopropyl dimethylbetaine; dodecyldimethylbetaine; tetradecyldimethylbetaine; cetyldimethylbetaine; cetylamidopropyldimethylbetaine, tetradecyldimethylbetaine, tetradecylamidopropyldimethylbetaine, and docosyldimethylammonium hexanoate and mixtures thereof.
Betaine surfactants are unique ingredients that provide exceptional benefits. When betaine surfactant and polymeric surfactant are combined with any anionic surfactant with, or without magnesium ions being present, superior grease holding benefits are provided.
Betaines containing a C₁₂₋₁₄ alkyl provide a much bigger benefit when combined with polymeric surfactant than when used by themselves.
The betaine is preferably present at a level of from $\frac{1}{2}$
% to 15% by weight of the formula, preferably from 1% to 10%, most preferably from 1% to 8%. The ratio of anionic detergent surfactants to the betaine is from 1 to 80, preferably from 1 to 40, more preferably from 2 to 40.
When betaines are present, the composition should preferably have a ratio of betaine to polymeric surfactant of more than 7:1, preferably more than 9:1.

Solvents

Alcohols, such as ethyl alcohol, and hydrotropes, such as sodium and potassium toluene sulfonate, sodium and potassium xylene sulfonate, trisodium sulfosuccinate and related compounds (as disclosed in U.S. Patent 3,915,903), and urea, can be utilized in the interests of achieving a desired product phase stability and viscosity. Alkanols containing from one to six carbon atoms, especially two, and especially ethyl alcohol can be present. Ethyl alcohol at a level of from 0% to 15%, preferably from 1% to 6%, and potassium and/or sodium toluene, xylene, and/or cumene sulfonates at a level of from 1% to 6% can be used in the compositions of the invention. The viscosity should be greater than 0.1 Pa.s, more preferably greater than 0.14 Pa.s, more preferably greater than 0.2 Pa.s for consumer acceptance.
However the polymeric surfactant can be used to reduce the viscosity and provide phase stability, e.g., when either the preferred alkyl polyethoxylate sulfate or magnesium ions are present in the composition. For viscosity reduction, the percentage of ethylene oxide in the polymer should be less than 70%, preferably less than 50%. Preferred compositions contain less than 2% alcohol and less than 3% hydrotrope and preferably essentially none while maintaining a viscosity of from 0.15 Pa.s to 0.5 Pa.s, preferably from 0.2 Pa.s to 0.4 Pa.s. If viscosity reduction is not desired the percentage of ethylene oxide in the polymer should be more than 50%, preferably more than 70%. The polymeric surfactant reduces viscosity for all water soluble anionic surfactants.
The compositions of this invention contain from 20% to 90%, preferably from 30% to 80%, water.

Additional Optional Ingredients

The compositions of this invention can contain up to 10%, by weight of selected detergency builders either of the organic or inorganic type. Examples of water-soluble inorganic builders which can be used, alone or in admixture with themselves and organic alkaline sequestrant builder salts, are alkali metal carbonates, phosphates, polyphosphates, and silicates. Specific examples of such salts are sodium tripolyphosphate, sodium carbonate, potassium carbonate, sodium pyrophosphate, potassium pyrophosphate, and potassium tripolyphosphate. Examples of organic builder salts which can be used alone, or in admixture with each other or with the preceding inorganic alkaline builder salts, are alkali metal polycarboxylates, e.g., water-soluble citrates and tartrates, such as sodium and potassium citrate and sodium and potassium tartrate. In general, however, detergency builders have limited value in dishwashing detergent compositions and use at levels above 10% can restrict formulation flexibility in liquid compositions because of solubility and phase stability considerations. It is preferred that any builder used be relatively specific to control of calcium as opposed to magnesium, Citrates, tartrates, malates, maleates, succinates and malonates are especially preferred.
The detergent compositions of this invention can contain, if desired, any of the usual adjuvants, diluents and additives, for example, perfumes, electrolytes, enzymes, dyes, antitarnishing agents and antimicrobial agents, without detracting from the advantageous properties of the compositions. Alkalinity sources and pH buffering agents such as monoethanolamine, triethanolamine and alkali metal hydroxides can also be utilized.
When the anionic surfactant is a C₁₀-C₂₀ alkylpolyethoxylate sulfate surfactant containing from 0.25 to 10 ethoxy groups per molecule on average, the pH should be above 6, preferably above 7 to avoid hydrolysis of the ester linkage. Also, it is desirable that the composition be substantially free of antibacterial agents such as N-trichloromethyl-thio-4-cyclohexene-1,2,dicarboximide for safety.
Low levels of antibacterial agents that will prevent growth of bacteria or molds in the product, but which have essentially no effect in use can be desirable, especially when low levels of alcohol are present.
All percentages and ratios herein are by weight unless otherwise indicated.
The following examples are given to illustrate the compositions of the invention.

In the following examples, the compounds have the following definitions. E stands for an ethoxylate group and P stands for a propoxylate group.

Name	Formula	MW	HLB
Tetronic 504	(E₈P_8.5)₄(=NCH₂CH₂N=)	3400	15.5
Tetronic 702	(E_4.5P₁₄)₄(=NCH₂CH₂N=)	4000	7
Tetronic 704	(E_12.5P₁₄)₄(=NCH₂CH₂N=)	5500	15
Tetronic 707	(E_47.5P₁₄)₄(=NCH₂CH₂N=)	12000	27
Tetronic 902*	(E₆P₁₇)₄(=NCH₂CH₂N=)	5300	6.5
Tetronic 904*	(E₁₇P₁₇)₄(=NCH₂CH₂N=)	7500	14.5
Tetronic 907*	(E₅₅P₁₇)₄(=NCH₂CH₂N=)	13900	26
Tetronic 908	(E₉₁P₁₇)₄(=NCH₂CH₂N=)	20000	30.5
Tetronic 1307	(E₇₄P₂₄)₄(=NCH₂CH₂N=)	18600	23.5
Tetronic 1502*	(E₁₀P₃₁)₄(=NCH₂CH₂N=)	9000	5
Tetronic 1504	(E_28.5P₃₁)₄(=NCH₂CH₂N=)	12500	13
Tetronic 70R4	(P₁₄E_12.5)₄(=NCH₂CH₂N=)	5500

* Prepared by blending other commercially available materials.
Tetronic is a Registered Trade Mark of the Union Carbide Co.

The base product contains 5% magnesium C₁₂₋₁₃ alkyl sulfate, 23% mixed magnesium and ammonium C₁₂₋₁₃ alkyl polyethoxylate (1) sulfate, 2.7% C₁₂₋₁₃ alkyl dimethyl amine oxide; 5% ethyl alcohol, 3% sodium toluene sulfonate, about 60% water, and the balance being inorganic salts and minor ingredients.
In the following examples, "grease cutting" is determined by the following test. A preweighed 250 cc. polypropylene cup has 3 cc. of a melted beef grease applied to its inner bottom surface. After the grease has solidified, the cup is reweighed. Then a 0.4% aqueous solution of the composition to be tested is added to the cup to completely fill it. The aqueous solution has a temperature of 46°C. After 15 minutes, the cup is emptied and rinsed with distilled water. The cup is dried and then weighed to determine the amount of grease removal. The amount removed by the base product is indexed at 100.
In the following examples, "grease capacity" is determined by modifying the above grease cutting test by using 10 ml of an easier to remove fat which is an 80/20 mixture of a solid vegetable shortening and a liquid vegetable shortening, lowering the detergent concentration to about 0.2%, and soaking for 30 minutes to allow equilibrium to occur.
In the Examples "*" indicates a significant difference and the figures in parentheses under the headings "Grease Capacity" and "Grease Cutting" are the number of replicates run and averaged to give the indicated test scores.
In all of the Examples, the viscosity of the composition is greater than about 1.5 Pa.s and less than about 5 Pa.s centipoise.

EXAMPLE I

This test shows the improvement in grease capacity and grease cutting obtainable with various Tetronics.

EXAMPLE II

This example demonstrates that reversing the order of addition of the ethylene oxide and propylene oxide to create a hydrophilic center and hydrophobic ends provides compounds which are equally as effective as the Tetronics.

EXAMPLE III

This example demonstrates that a polymeric surfactant with a somewhat hydrophilic center, two or more intermediate hydrophobic moieties and terminal hydrophilic moieties provides almost the same benefits as the Tetronics.

EXAMPLE IV

This example demonstrates that a compound with a hydrophilic chain with grafted polypropylene oxide hydrophobic chains can provide grease capacity and grease cutting benefits in accordance with the invention.

EXAMPLE V

This example shows that similar structures in which alkylene chains are substituted, at least in part, for polypropoxylate moieties provide benefits in accordance with the present invention.

COMPARATIVE EXAMPLE VI

This example demonstrates that mixtures of polypropylene glycol and polyethylene glycol, and the individual materials do not provide the benefits.

COMPARATIVE EXAMPLE VII

This example demonstrates that excessively water-soluble compounds and compounds which are more like conventional surfactants and contain terminal oleophilic hydrophobic groups do not provide the benefits.

COMPARATIVE EXAMPLE VIII

This example is a continuation of Example VII.

COMPARATIVE EXAMPLE IX

This example also demonstrates that other conventional surfactants do not provide the benefits.

EXAMPLE X

This example, shows the effect of increased Tetronic surfactant. Above 4%, there is a loss which becomes substantial before a level of about 9% is reached.

COMPARATIVE EXAMPLE XI

This example shows the effect of using twice the amount of a commercial detergent. The Grease Capacity and Grease Cutting are increased, but at a much greater cost than associated with the invention.

Grease Capacity Grease Cutting Total

Reps (4) (4) -

Base Product 100 100 200

Base Product (Double Usage) 140* 130* 270*

LSD₁₀ 8 10 13

EXAMPLE XII

Viscosity Reduction
This example demonstrates the large reductions in viscosity obtained by adding the polymeric surfactant. The viscosity can be adjusted back up by reducing alcohol and/or hydrotrope levels. As can be seen, the higher the level of ethoxylate moieties in the polymers, the less the reduction in viscosity.

Additional Materials Description

The additional polymeric surfactants not defined hereinbefore are as follows:

Name Formula MW HLB

Tetronic 1302 (E₉ P₂₄)₄ (=NCH₂CH₂N=) 7800 5.5

Tetronic 1304 (E₂₄ P₂₄)₄ (=NCH₂CH₂N=) 10500 13.5

EXAMPLE XIII

In this example, a different type of test was used to demonstrate another aspect of grease control by the detergent compositions. In most cases, this test gives a ranking between formulations similar to that of the total index value of the preceeding examples.
This test determines the effectiveness or strength of the grease emulsification by the detergent by measuring the level of grease deposition on a hydrophobic surface after its exposure to a detergent solution to which a grease has been added. This test models the actual situation of redeposition of greases onto later washed items, especially plastics.
For this experiment, 7.6 ℓ (2 gallons) of median hardness water [102.6 x 10⁻³ g/ℓ] (6 grains/gallon) were held at 40.6°C (105°F), a common end-of-wash temperature for dishwater. A 0.1% solution of the detergent product was made and mild agitation was begun. Liquid vegetable oil was added in 6cc increments. At totals of 18cc, 36cc, and 54cc, plastic items (3 for each grease level, 9 total) are dipped in succession into the water. After drying , the mean weight gain per plastic item unit area is calculated and indexed to a reference product.
The reference product used here is the base product. The polymeric surfactant is added at the 1% level to the base.
A "*" indicates a statistically significant (LSD₀₅) reduction in grease redeposition compared to the Base Product.
The compounds tested herein were those of formula 3.

in which, in compound,

P: X=8, Y=4
Q: X=8, Y=14
R: X=43, Y=4
S: X=43, Y=14
T: X=17, Y=10

Note from the above that Tetronic 704 and Compound F did not excel in this test, but did perform well in the previous examples. Again, the Methocel® polymer does not provide sufficient benefit.
Also, certain very high molecular weight compounds (R and S) do not show any advantage.

PREFERRED PROCESS

When some of the compositions of this invention are first made, they are not at equilibrium. They typically require an aging period to reach equilibrium and exhibit the full benefit. A period of about two weeks, which is about equivalent to the normal time between making and use by the consumer is usually sufficient.

Claims

A high sudsing liquid detergent composition with enhanced grease handling ability containing by weight:
(a) from 5% to 50% anionic surfactant;

(b) from 0.1% to 10% of polymeric surfactant containing polymerised ethylene oxide and/or propylene oxide groups, said polymeric surfactant having a molecular weight of from 400 to 60,000;

(c) from 0% to 10% of a suds stabilizing nonionic surfactant selected from fatty acid amides, trialkyl amine oxides and mixtures thereof;

(d) from 0% to 10% of a detergency builder selected from inorganic phosphates, inorganic polyphosphates, inorganic silicates, inorganic carbonates, organic carboxylates, organic phosphonates, and mixtures thereof;

(e) from 0% to 15% of an alkanol containing from one to six carbon atoms; and

(f) from 20% to 90% water,
characterised in that said polymeric surfactant is selected from compounds of formula

1) [R¹(R²O)_n(R³0)_m]_y[R⁴]

wherein R¹ is hydrogen, each R² or R³ is an alkylene group containing from two to six carbon atoms with no more than 90% of said molecule comprising R² or R³ groups containing two carbon atoms the (R₂O) and (R₃O) groups being interchangeable; wherein R⁴ is selected from
i) alkylene groups containing from one to 18 carbon atoms,

ii) poly (hydroxyalkylene oxide) groups wherein each alkylene group has from one to six hydroxy groups and contains from three to eight carbon atoms and there are from to two fifty hydroxyalkylene oxide groups and from two to fifty hydroxy groups,

iii) (=NR²N=), and

(iv) =N (̵R²NH)̵_x,
wherein n is from 0 to 500, m is from 0 to 500, n+m is from 5 to 1000, x is from 2 to 50, and y is from 2 to 50 and equal to the available bonds of R⁴,

2) R¹ (̵OCH₂CH₂)̵_xR²(̵OCH₂CH₂)̵_yOR¹

where: R¹ is H, CH₃, or CH₃(CH₂)_n where n is 1-17, or unsaturated analogues thereof, each of x and y is 2-500, and R² is -O(CH₂)̵_z
where z = 1-18, or unsaturated analogues thereof, the percentage of (̵OCH₂CH₂)̵ groups in the molecule being less than 90%;
wherein x is 8 and y is 4 or 14 or x is 17 and y is 10.
wherein x is 7.5 or 16, and y is 2.75;
said composition having a pH of greater than six when the composition contains a C₁₀-C₂₀ alkylpolyethoxylate sulfate surfactant containing from 0.25 to 10 ethoxy groups per molecule on average and having a viscosity of greater than 0.1 Pa.s, said composition being substantially free of nonionic alkylpolyethoxylate detergent surfactant when the amount of anionic surfactant is less than 20%, said anionic surfactant being a C₁₀-C₂₀ alkyl polyethoxylate sulfate surfactant salt containing from 0.25 to 10 ethoxy groups per molecule on the average when no magnesium ions or betaine surfactants are present.
A composition according to Claim 1 wherein there is from 0.1% to 7%, preferably from 0.5% to 4%, polymeric surfactant.
A composition according to either one of claims 1 & 2 wherein the anionic detergent is selected from sodium, ammonium, monoethanolammonium, diethanolammonium, triethanolammonium, potassium and magnesium salts of alkyl sulfates containing 8-18 carbon atoms, alkyl benzene sulfonates in which the alkyl group contains form 9 to 15 carbon atoms, and alkyl polyethoxylate sulfates in which the alkyl group contains from 10 to 20 carbon atoms and there are from 0.5 to 10 ethoxylate groups on the average, and mixtures thereof.
A composition according to any one of claims 1-3 wherein there is less than 2% polymeric surfactant and in which from 10% to 100% of the anionic surfactant is in the form of a magnesium salt.
A composition according to any one of claims 1-3 wherein there is at least 8% of an alkylpolyethoxylate sulfate containing from 10 to 16 carbon atoms in the alkyl group and from 0.5 to 8 ethoxylates on the average; wherein from 20% to 90% of the anionic surfactant is the magnesium salt.
A composition according to any one of claims 1-4 wherein the anionic surfactant comprises at least 10% alkylpolyethoxylate sulfate in which the alkyl group contains from 10 to 20 carbon atoms and containing from 1 to 6 ethoxylates on the average, alkyl sulfates containing from 8 to 18 carbon atoms on the average, and mixtures thereof, and wherein the suds stabilizing nonionic surfactant is an amine oxide semipolar nonionic surface active agent comprising compounds having the formula:
wherein R¹ is an alkyl, 2-hydroxyalkyl, 3-hydroxyalkyl, or 3-alkoxy-2-hydroxypropyl radical in which the alkyl and alkoxy groups, respectively, contain from 8 to 18 carbon atoms, R² and R³ are each a methyl, ethyl, propyl, isopropyl, 2-hydroxyethyl, 2-hydroxypropyl, or 3-hydroxypropyl radical and n is from 0 to 10.
A composition according to claim 4 when dependent on claim 3, wherein the anionic surfactant is selected from mixtures of alkylbenzene sulfonates in which the alkyl group contains from 9 to 15 carbon atoms and alkylpolyethoxylate sulfates in which the alkyl group contains from 10 to 16 carbon atoms and there are from 0.5 to 6 ethoxylates on the average and in which the suds stabilizing nonionic surfactant is a fatty acid amide represented by the general formula:

R¹-CO-N(H)_m(R²OH)_2-m

wherein R₁ is a saturated or unsaturated, aliphatic hydrocarbon radical having from 7 to 21 carbon atoms, R² represents a methylene or ethylene group; and m is 1 or 2 and there is from 2% to 8% of said fatty acid amide.
A composition according to any one of claims 1-3 wherein there is from 0.5% to 4% polymeric surfactant, in which surfactant the amount of ethylene oxide is less than 70% by weight, said composition containing less than 2% alkanol and less than 3% of a hydrotrope material, and having a viscosity of from 0.15 to 0.5 Pa.s.
A composition according to claim 8 wherein there is less than 2% polymeric surfactant, in which surfactant the amount of ethylene oxide in the polymeric surfactant is less than 50% by weight, and wherein the viscosity is from 0.2 to 0.4 Pa.s.