EP0550652B1

EP0550652B1 - Detergent compositions containing alkyl ethoxy carbozylates and polyhydroxy fatty acid amides

Info

Publication number: EP0550652B1
Application number: EP91918309A
Authority: EP
Inventors: Yi-Chang Fu; Jeffrey John Scheibel
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1990-09-28
Filing date: 1991-09-25
Publication date: 1994-05-04
Anticipated expiration: 2011-09-25
Also published as: DK0550652T3; FI931363A0; AU663855B2; ATE105332T1; NO301283B1; JPH06501730A; EG19520A; SK25793A3; PT99085A; RU2105790C1; DE69101928T2; CZ40593A3; MY109694A; FI931363A; EP0550652A1; DE69101928D1; HU213735B; HU9300895D0; WO1992006157A1; BR9106896A

Abstract

Disclosed are detergent compositions comprising and alkyl ethoxy carboxylate component and a polyhydroxy fatty acid amide component. The detergent compositions of the present invention possess improved cleaning and sudsing properties and exhibit enhanced mildness to the skin. Also disclosed is a method for cleaning soiled dishes by treating said dishes with the detergent compositions disclosed herein.

Description

TECHNICAL FIELD

The present invention relates to detergent compositions comprising alkyl ethoxy carboxylates and polyhydroxy fatty acid amides. In particular, it relates to detergent compositions which possess desirable cleaning and sudsing properties, and are especially suitable for use in dishwashing applications.

BACKGROUND OF THE INVENTION

Alkyl ethoxy carboxylates, and their use in detergent compositions, are known in the art. U.S. Patent Application Serial No. 516,292, entitled "Light-Duty Liquid Dishwashing Detergent Composition Containing an Alkyl Ethoxy Surfactant," filed May 4, 1989 on behalf of Rodney M. Wise and Thomas A. Cripe, discloses such carboxylates and their use in detergent compositions. While these carboxylates provide improved cleaning performance, the suds they produce generally have poor initial volume and poor stability. This poor suds volume and stability may cause an incorrect perception on the part of the consumer that the detergent compositions provide inferior cleaning performance. Therefore, it would be desirable to combine such carboxylates with a component or components which provide improved sudsing performance. It has been found that the compositions claimed in the present invention provide this desired effect.
The polyhydroxy fatty acid amide component contained in the composition of the present invention is known in the art, as are several of its uses.
N-acyl, N-methyl glucamides, for example, are disclosed by J. W. Goodby, M. A. Marcus, E. Chin, and P. L. Finn in "The Thermotropic Liquid-Crystalline Properties of Some Straight Chain Carbohydrate Amphiphiles," Liquid Crystals, 1988, Volume 3, No. 11, pp 1569-1581, and by A. Muller-Fahrnow, V. Zabel, M. Steifa, and R. Hilgenfeld in "Molecular and Crystal Structure of a Nonionic Detergent: Nonanoyl-N-methylglucamide," J. Chem. Soc. Chem. Commun., 1986, pp 1573-1574. The use of N-alkyl polyhydroxyamide surfactants has been of substantial interest recently for use in biochemistry, for example in the dissociation of biological membranes. See, for example, the journal article "N-D-Gluco-N-methyl-alkanamide Compounds, a New Class of Non-Ionic Detergents For Membrane Biochemistry," Biochem. J. (1982), Vol. 207, pp 363-366, by J. E. K. Hildreth.
The use of N-alkyl glucamides in detergent compositions has also been discussed. U.S. Patent 2,965,576, issued December 20, 1960 to E. R. Wilson, and G.B. Patent 809,060, published February 18, 1959, assigned to Thomas Hedley & Co., Ltd. relate to detergent compositions containing anionic surfactants and certain amide surfactants, which can include N-methyl glucamide, added as a low temperature suds enhancing agent. These compounds include an N-acyl radical of a higher straight chain fatty acid having 10-14 carbon atoms. These compositions may also contain auxiliary materials such as alkali metal phosphates, alkali metal silicates, sulfates, and carbonates. It is also generally indicated that additional constituents to impart desirable properties to the composition can also be included in the compositions, such as fluorescent dyes, bleaching agents, perfumes, etc.
U.S. Patent 2,703,798, issued March 8, 1955 to A. M. Schwartz, relates to aqueous detergent compositions containing the condensation reaction product of N-alkyl glucamine and an aliphatic ester of a fatty acid. The product of this reaction is said to be useable in aqueous detergent compositions without further purification. It is also known to prepare a sulfuric ester of acylated glucamine as disclosed in U.S. Patent 2,717,894, issued September 13, 1955, to A. M. Schwartz.
PCT International Application WO 83/04412, published December 22, 1983, by J. Hildreth, relates to amphiphilic compounds containing polyhydroxyl aliphatic groups said to be useful for a variety of purposes including use as surfactants in cosmetics, drugs, shampoos, lotions, and eye ointments, as emulsifiers and dispensing agents for medicines, and in biochemistry for solubilizing membranes, whole cells, or other tissue samples, and for preparing liposomes. Included in this disclosure are compounds of the formula R'CON(R)CH₂R" and R"CON(R)R' wherein R is hydrogen or an organic grouping, R' is an aliphatic hydrocarbon group of at least three carbon atoms, and R" is the residue of an aldose.
European Patent 0 285 768, published October 12, 1988, H. Kelkenberg, et al., relates to the use of N-polyhydroxy alkyl fatty acid amides as thickening agents in aqueous detergent systems. Included are amides of the formula R₁C(O)N(X)R₂ wherein R₁ is a C₁-C₁₇ (preferably C₇-C₁₇) alkyl, R₂ is hydrogen, a C₁-C₁₈ (preferably C₁-C₆) alkyl, or an alkylene oxide, and X is a polyhydroxy alkyl having four to seven carbon atoms, e.g., N-methyl, coconut fatty acid glucamide. The thickening properties of the amides are indicated as being of particular use in liquid surfactant systems containing paraffin sulfonate, although the aqueous surfactant systems can contain other anionic surfactants, such as alkylaryl sulfonates, olefin sulfonate, sulfosuccinic acid half ester salts, and fatty alcohol ether sulfonates, and nonionic surfactants such as fatty alcohol polyglycol ether, alkylphenol polyglycol ether, fatty acid polyglycol ester, polypropylene oxide-polyethylene oxide mixed polymers, etc. Paraffin sulfonate/N-methyl coconut fatty acid glucamide/nonionic surfactant shampoo formulations are exemplified. In addition to thickening attributes, the N-polyhydroxy alkyl fatty acid amides are said to have superior skin tolerance attributes.
U.S. Patent 2,982,737, issued May 2, 1961, to Boettner, et al., relates to detergent bars containing urea, sodium lauryl sulfate anionic surfactant, and an N-alkylglucamide nonionic surfactant which is selected from N-methyl,N-sorbityl lauramide and N-methyl, N-sorbityl myristamide.
Other glucamide surfactants are disclosed, for example, in DT 2,226,872, published December 20, 1973, H. W. Eckert, et al., which relates to washing compositions comprising one or more surfactants and builder salts selected from polymeric phosphates, sequestering agents, and washing alkalis, improved by the addition of an N-acylpolyhydroxyalkyl-amine of the formula R₁C(O)N(R₂)CH₂(CHOH)_nCH₂OH, wherein R₁ is a C₁-C₃ alkyl, R₂ is a C₁₀-C₂₂ alkyl, and n is 3 or 4. The N-acylpolyhydroxyalkyl-amine is added as a soil suspending agent.
U.S. Patent 3,654,166, issued April 4, 1972, to H. W. Eckert, et al., relates to detergent compositions comprising at least one surfactant selected from the group of anionic, zwitterionic, and nonionic surfactants and, as a textile softener, an N-acyl, N-alkyl polyhydroxyalkyl compound of the formula R₁N(Z)C(O)R₂ wherein R₁ is a C₁₀-C₂₂ alkyl, R₂ is a C₇-C₂₁ alkyl, R₁ and R₂ total from 23 to 39 carbon atoms, and Z is a polyhydroxyalkyl which can be -CH₂(CHOH)_m-CH₂OH where m is 3 or 4.
U.S. Patent 4,021,539, issued May 3, 1977, to H. Moller, et al., relates to skin treating cosmetic compositions containing N-polyhydroxyalkyl-amines which include compounds of the formula R₁N(R)CH(CHOH)_mR₂ wherein R₁ is H, lower alkyl, hydroxy-lower alkyl, or aminoalkyl, as well as heterocyclic aminoalkyl, R is the same as R₁ but both cannot be H, and R₂ is CH₂OH or COOH.
French Patent 1,360,018, April 26, 1963, assigned to Commercial Solvents Corporation, relates to solutions of formaldehyde stabilized against polymerization with the addition of amides of the formula RC(O)N(R₁)G wherein R is a carboxylic acid functionality having at least seven carbon atoms, R₁ is hydrogen or a lower alkyl group, and G is a glycitol radical with at least 5 carbon atoms.
German Patent 1,261,861, February 29, 1968, A. Heins, relates to glucamine derivatives useful as wetting and dispersing agents of the formula N(R)(R₁)(R₂) wherein R is a sugar residue of glucamine, R₁ is a C₁₀-C₂₀ alkyl radical, and R₂ is a C₁-C₅ acyl radical.
G.B. Patent 745,036, published February 15, 1956, assigned to Atlas Powder Company, relates to heterocyclic amides and carboxylic esters thereof that are said to be useful as chemical intermediates, emulsifiers, wetting and dispersing agents, detergents, textile softeners, etc. The compounds are expressed by the formula N(R)(R₁)C(O)R₂ wherein R is the residue of an anhydrized hexane pentol or a carboxylic acid ester thereof, R₁ is a monovalent hydrocarbon radical, and -C(O)R₂ is the acyl radical of a carboxylic acid having from 2 to 25 carbon atoms.
U.S. Patent 3,312,627, issued April 4, 1967 to D. T. Hooker, discloses solid toilet bars that are substantially free of anionic detergents and alkaline builder materials, and which contain lithium soap of certain fatty acids, a nonionic surfactant selected from certain propylene oxide-ethylenediamine-ethylene oxide condensates, propylene oxide-propylene glycol-ethylene oxide condensates, and polymerized ethylene glycol, and also contain a nonionic lathering component which can include polyhydroxyamide of the formula RC(O)NR¹(R₂) wherein RC(O) contains from about 10 to about 14 carbon atoms, and R¹ and R² each are H or C₁-C₆ alkyl groups, said alkyl groups containing a total number of carbon atoms of from 2 to about 7 and a total number of substituent hydroxyl groups of from 2 to about 6. A substantially similar disclosure is found in U.S. Patent 3,312,626, also issued April 4, 1967 to D. T. Hooker.
However, none of these references teach combining an alkyl ethoxy carboxylate and a polyhydroxy fatty acid amide in a detergent composition. Furthermore, nothing in the art teaches the unexpected improved sudsing characteristics and improved cleaning properties, especially grease cleaning properties, of such detergent compositions.
There is also nothing in the art which teaches the mildness to the hand exhibited by such detergent compositions.
It is therefore an object of the present invention to provide for detergent compositions containing an alkyl ethoxy carboxylate and a polyhydroxy fatty acid amide which exhibit improved sudsing and cleaning properties, and are mild to the skin.
It is still another object of the present invention to provide a method for cleaning soiled dishes by treating said dishes with the particular detergent compositions described herein.
These objects are realized by the present invention.

SUMMARY OF THE INVENTION

The present invention is directed to detergent compositions comprising from about 1%, preferably about 5%, to about 65% by weight of a surfactant mixture comprising:

(a) from about 5% to about 95% by weight of one or more alkyl ethoxy carboxylates having the general formula

RO(CH₂CH₂O)_kCH₂COO⁻M⁺

wherein R is a C₈-C₂₂ alkyl group, k is an integer ranging from 0 to 10, and M is a cation;
(b) from about 5% to about 95% by weight of one or more polyhydroxy fatty acid amides having the general formula
wherein R¹ is H, a C₁-C₄ hydrocarbyl, 2-hydroxy ethyl, 2-hydroxy propyl, or mixtures thereof, R² is a C₅-C₃₁ hydrocarbyl, and Z is a polyhydroxyhydrocarbyl having a linear hydrocarbyl chain with at least 3 hydroxyl groups directly connected to the chain, or an alkoxylated derivative thereof.

The present invention is also directed toward a method for cleaning soiled dishes, said method comprising treating said dishes with the detergent compositions claimed herein.

DETAILED DESCRIPTION OF THE INVENTION

The detergent compositions of the present invention are preferably liquid or gel detergent compositions, more preferably light-duty liquid detergent compositions, most preferably light-duty liquid dishwashing detergent compositions. These detergent compositions comprise from about 5% to about 65% by weight, preferably from about 10% to about 50% by weight, most preferably from about 20% to about 40% by weight of a surfactant mixture comprising one or more alkyl ethoxy carboxylates and one or more polyhydroxy fatty acid amides. These and other optional ingredients typically found in detergent compositions are set forth below.

Alkyl Ethoxy Carboxylate Component

The surfactant mixture of the present invention comprises from about 5% to about 95% by weight, preferably from about 20% to about 80% by weight, more preferably from about 40% to about 60% by weight of one or more alkyl ethoxy carboxylates having the general formula

RO(CH₂CH₂O)_kCH₂COO⁻M⁺ (I)

wherein R is a C₈-C₂₂ alkyl group, preferably a C₁₂-C₁₄ alkyl group, k is an integer ranging from 0 to 10, preferably from 1 to 5, and M is a cation, preferably an alkali metal, alkaline earth metal, ammonium, lower alkanol ammonium, and mono-, di-, and triethanolammonium, more preferably sodium, potassium and ammonium, most preferably sodium and potassium, and mixtures thereof with magnesium and calcium ions. The number of carbon atoms on the R group and the value of the integer k are interrelated in that if the number of carbon atoms on the R group is increased, then it is preferable that the value of the integer k be correspondingly increased to preserve the solubility of the detergent compound. Typically, when R is a C₁₂-C₁₄ alkyl group, k will be in the range of from about 1 to about 4, when R is a C₁₂-C₁₈ alkyl group, k will be in the range of from about 1 to about 6, and when R is a C₈-C₁₂ alkyl group, k will be in the range of from 0 to about 3.
The alkyl ethoxy carboxylate component of the present invention may be prepared by methods known in the art. One preferred method is disclosed in U.S. Patent Application Serial No. 354,968, entitled "Process for Making Alkyl Ethoxy Carboxylates," filed May 22, 1989 on behalf of Thomas A. Cripe, the disclosure of which is incorporated herein.
The alkyl ethoxy carboxylate component of the present invention may comprise a distribution of alkyl ethoxy carboxylates. When the composition of the present invention does comprise such a distribution, the ethoxylate distribution will be such that, on a weight basis, the amount of material where k is 0 is less than about 20%, preferably less than about 15%, most preferably less than about 10%, and the amount of material where k is greater than 7 is less than about 25%, preferably less than about 15%, most preferably less than about 10%. The average k will fall in the range of from 1 to 4 when the average R is C₁₃ or less, and the average k will fall in the range of from 2 to 6 when the average R is greater than C₁₃. Such a distribution, and its preparation, is described in greater detail in U.S. Patent Application No. 516,292, filed May 4, 1989, the disclosure of which is incorporated herein. When the compositions of the present invention are comprised of a distribution of ethoxy carboxylates, the desired distribution of carboxylates may be derived by reacting a corresponding distribution of ethoxylated alcohol precursors.
It has been found that the presence of divalent cations with the alkyl ethoxy carboxylates in the compositions of the present invention greatly improves the cleansing of greasy soils. This is especially true when the composition is used in softened water that contains few divalent ions. It is believed that divalent ions increase the packing of the alkyl ethoxy carboxylates at the oil/water interface, thereby producing reduced interfacial tension and improved grease cleaning. However, liquid detergent compositions used in dishwashing applications which contain alkyl ethoxy carboxylates and which do not conform to the narrow definition of this invention will benefit less from the addition of divalent ions and, in many cases, will actually exhibit reduced cleaning performance upon the addition of divalent cations.
When included in the compositions of the present invention, the divalent ions are preferably added as a chloride, sulfate salt, or a hydroxide, most preferably the chloride salt, to compositions containing alkali metal or ammonium salts of the alkyl ethoxy carboxylates, most preferably sodium or potassium salts, after the composition has been neutralized with a strong base. The concentration of divalent ion is typically in the range of from 0% to about 1.5%, preferably from about 0.2% to about 1%, most preferably from about 0.3% to about 0.8% by weight. Magnesium and calcium ions are particularly preferred divalent ions.
Depending upon the preparation method utilized to prepare the alkyl ethoxy carboxylate component of the present invention, and the method of preparation of the compositions of the present invention, such compositions may also contain from 0% to about 5.0%, preferably less than 4.0%, more preferably less than 2.5% by weight of alcohol ethoxylates of the formula

R'O(CH₂CH₂O)_wH (II)

wherein R' is a C₁₂-C₁₆ alkyl group and w is in the range of from 0 to about 10, with the average w being less than 6.
The uncarboxylated alcohol ethoxylates of structure (II) are a detriment to the alkyl ethoxy carboxylate-containing compositions of the present invention. Therefore, it is critical that such compositions contain no more than about 5.0% by weight of the alcohol ethoxylates from which the alkyl ethoxy carboxylates are derived. Although commercially available alkyl ethoxy carboxylates contain 10% or more of alcohol ethoxylates, there are known routes to obtain the desired high purity alkyl ethoxy carboxylates. For example, unreacted alcohol ethoxylates can be removed by steam distillation, U.S. Pat. No. 4,098,818 (Example I), or by recrystallization of the alkyl ethoxy carboxylate, British Pat. No. 1,027,481 (Example I). Other routes to the desired carboxylates are the reaction of sodium hydroxide or sodium metal and monochloracetic acid, or its salt, with alcohol ethoxylates under special pressure and temperature conditions, as described in U.S. Pat. Nos. 3,992,443 and 4,098,818; and Japanese Patent Application No. 50-24215, all incorporated herein.
Other routes to high purity alkyl ethoxy carboxylates are disclosed in U.S. Patent Application Serial No. 516,292, filed May 4, 1989, already referred to herein, which is incorporated herein.

Polyhydroxy Fatty Acid Amide Component

The surfactant mixture of the present invention further comprises from about 5% to about 95% by weight, preferably from about 20% to about 80% by weight, more preferably from about 20% to about 60% by weight of one or more polyhydroxy fatty acid amides having the formula

wherein: R¹ is H, C₁-C₄ hydrocarbyl, 2-hydroxy ethyl, 2-hydroxy propyl, or a mixture thereof, preferably C₁-C₄ alkyl, more preferably C₁ or C₂ alkyl, most preferably C₁ alkyl (i.e., methyl); and R² is a C₅-C₃₁ hydrocarbyl, preferably straight chain C₇-C₁₉ alkyl or alkenyl, more preferably straight chain C₉-C₁₇ alkyl or alkenyl, most preferably straight chain C₁₁-C₁₇ alkyl or alkenyl, or mixture thereof; and Z is a polyhydroxyhydrocarbyl having a linear hydrocarbyl chain with at least 3 hydroxyls directly connected to the chain, or an anhydro derivative derived by dehydration of such polyhydroxyhydrocarbyl, or an alkoxylated derivative (preferably ethoxylated or propoxylated) thereof. Z preferably will be derived from a reducing sugar in a reductive amination reaction; more preferably Z is a glycityl. Suitable reducing sugars include glucose, fructose, maltose, lactose, galactose, mannose, and xylose. As raw materials, high dextrose corn syrup, high fructose corn syrup, and high maltose corn syrup can be utilized as well as the individual sugars listed above. These corn syrups may yield a mix of sugar components for Z. It should be understood that it is by no means intended to exclude other suitable raw materials. Z preferably will be selected from the group consisting of -CH₂-(CHOH)n-CH₂OH, -CH(CH₂OH)-(CHOH)_n-1-CH₂OH, -CH₂-(CHOH)₂(CHOR'')(CHOH)-CH₂OH, where n is an integer from 3 to 5, inclusive, and R'' is H or a cyclic or aliphatic monosaccharide, and alkoxylated derivatives thereof. Most preferred are glycityls wherein n is 4.
In Formula (I), R¹ can be, for example, N-methyl, N-ethyl, N-propyl, N-isopropyl , N-butyl, N-2-hydroxy ethyl, or N-2-hydroxy propyl.
R²-CO-N< can be, for example, cocamide, stearamide, oleamide, lauramide, myristamide, capricamide, palmitamide, tallowamide, etc.
Z can be 1-deoxyglucityl, 2-deoxyfructityl, 1-deoxymaltityl, 1-deoxylactityl, 1-deoxygalactityl, 1-deoxymannityl, 1-deoxymaltotriotityl, etc.
The most preferred polyhydroxy fatty acid amide has the general formula

wherein R² is a straight-chain C₁₁-C₁₇ alkyl or alkenyl group.
Methods for making polyhydroxy fatty acid amides are known in the art. In general, they can be made by reacting an alkyl amine with a reducing sugar in a reductive amination reaction to form a corresponding N-alkyl polyhydroxyamine, and then reacting the N-alkyl polyhydroxyamine with a fatty aliphatic ester or triglyceride in a condensation/amidation step to form the N-alkyl, N-polyhydroxy fatty acid amide product. Processes for making compositions containing polyhydroxy fatty acid amides are disclosed, for example, in G.B. Patent Specification 809,060, published February 18, 1959, by Thomas Hedley & Co., Ltd., U.S. Patent 2,965,576, issued December 20, 1960 to E. R. Wilson, and U.S. Patent 2,703,798, Anthony M. Schwartz, issued March 8, 1955, and U.S. Patent 1,985,424, issued December 25, 1934 to Piggott, each of which is incorporated herein by reference.
In one process for producing N-alkyl or N-hydroxyalkyl, N-deoxyglycityl fatty acid amides wherein the glycityl component is derived from glucose and the N-alkyl or N-hydroxyalkyl functionality is N-methyl, N-ethyl, N-propyl, N-butyl, N-hydroxyethyl, or N-hydroxy-propyl, the product is made by reacting N-alkyl- or N-hydroxyalkyl-glucamine with a fatty ester selected from fatty methyl esters, fatty ethyl esters, and fatty triglycerides in the presence of a catalyst selected from the group consisting of trilithium phosphate, trisodium phosphate, tripotassium phosphate, tetrasodium pyrophosphate, pentapotassium tripolyphosphate, lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, disodium tartrate, dipotassium tartrate, sodium potassium tartrate, trisodium citrate, tripotassium citrate, sodium basic silicates, potassium basic silicates, sodium basic aluminosilicates, and potassium basic aluminosilicates, and mixtures thereof. The amount of catalyst is preferably from about 0.5 mole % to about 50 mole %, more preferably from about 2.0 mole % to about 10 mole %, on an N-alkyl or N-hydroxyalkyl-glucamine molar basis. The reaction is preferably carried out at from about 138°C to about 170°C for typically from about 20 to about 90 minutes. When triglycerides are utilized in the reaction mixture as the fatty ester source, the reaction is also preferably carried out using from about 1 to about 10 weight % of a phase transfer agent, calculated on a weight percent basis of total reaction mixture, selected from saturated fatty alcohol polyethoxylates, alkylpolyglucosides, linear glucamide surfactant, and mixtures thereof.
Preferably, this process is carried out as follows:

(a) preheating the fatty ester to about 138°C to about 170°C;
(b) adding the N-alkyl N-hydroxyalkyl glucamine to the heated fatty acid ester and mixing to the extent needed to form a two-phase liquid/liquid mixture;
(c) mixing the catalyst into the reaction mixture; and
(d) stirring for the specified reaction time.

Also preferably, from about 2% to about 20% of preformed linear N-alkyl/N-hydroxyalkyl, N-linear glucosyl fatty acid amide product is added to the reaction mixture, by weight of the reactants, as the phase transfer agent if the fatty ester is a triglyceride. This seeds the reaction, thereby increasing reaction rate. A detailed experimental procedure is provided below in the section entitled Experimental.
The polyhydroxy "fatty acid" amide materials used herein also offer the advantages to the detergent formulator that they can be prepared wholly or primarily from natural, renewable, non-petrochemical feedstocks and are degradable. They also exhibit low toxicity to aquatic life.
It should be recognized that along with the polyhydroxy fatty acid amides of Formula (I), the processes used to produce them will also typically produce quantities of nonvolatile by-product such as esteramides and cyclic polyhydroxy fatty acid amide. The level of these by-products will vary depending upon the particular reactants and process conditions. Preferably, the polyhydroxy fatty acid amide incorporated into the detergent compositions hereof will be provided in a form such that the polyhydroxy fatty acid amide-containing composition added to the detergent contains less than about 2%, preferably less than about 0.5%, of cyclic polyhydroxy fatty acid amide. The preferred processes described above are advantageous in that they can yield rather low levels of by-products, including such cyclic amide by-product.

Optional Ingredients

Liquid Carrier

In a preferred embodiment, the detergent compositions of the present invention are liquid detergent compositions. These preferred liquid detergent compositions comprise from about 95% to about 35% by weight, preferably from about 90% to about 50% by weight, most preferably from about 80% to about 60% by weight of a liquid carrier, e.g., water, preferably a mixture of water and a C₁-C₄ monohydric alcohol (e.g., ethanol, propanol, isopropanol, butanol, and mixtures thereof), with ethanol being the preferred alcohol.

Composition pH

The liquid detergent compositions hereof will preferably be formulated such that during use in aqueous cleaning operations the wash water will have a pH of between about 8 and about 10, more preferably between about 8.5 and about 9.5. Liquid product formulations of the present invention are prepared at a pH in the range of from about 7.0 to about 11.0, preferably from about 8.5 to about 10.5, more preferably from about 8.8 to about 10.0. The liquid detergent compositions may be adjusted to these pH levels using methods known to those skilled in the art, for example by adding a base to the compositions. Traditionally, liquid dishwashing compositions have a pH of about 7. It has been found that when in the form of a liquid detergent, the compositions of the present invention exhibit greatly improved grease cleaning if formulated at an alkaline pH, as compared to a pH of below 7. This cleaning benefit appears to be unique to liquid detergent compositions containing the present alkyl ethoxy carboxylate component. Surprisingly, the compositions of this invention are still very mild to the hand at this alkaline pH.
It is desirable to include a buffering agent in order to prepare liquid detergent compositions having enhanced pH stability. Examples of typical buffering agents include, but are not necessarily limited to, glycine (preferred), N,N-bis(2-hydroxyethyl)glycine (preferred), tris(hydroxymethyl)aminomethane, triethanolamine, monoethanolamine, 2-amino-2-ethyl-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol, N-methyl diethanol amine, 1,3-diamino-2-hydroxypropane, and mixtures thereof. When included in the liquid compositions prepared in accordance with the present invention, such buffering agents are typically present at a level of from about 0.1% to about 15% by weight, preferably from about 1% to about 7% by weight, most preferably from about 1.5% to about 5% by weight.

Thickening Agent

The detergent compositions of the present invention may also be in the form of a gel. Such compositions are typically formulated in the same manner as liquid detergent compositions, except they contain an additional thickening agent.
Any material or materials which can be admixed with the aqueous liquid to provide shear-thinning compositions having sufficient yield values can be used in the compositions of this invention. Materials such as colloidal silica, particulate polymers, such as polystyrene and oxidized polystyrene, combinations of certain surfactants, and water-soluble polymers such as polyacrylate are known to provide yield values.
A preferred thickening agent useful in the compositions of the present invention is a high molecular weight polycarboxylate polymer thickener. By "high molecular weight" it is meant from about 500,000 to about 5,000,000, preferably from about 750,000 to about 4,000,000.
The polycarboxylate polymer may be a carboxyvinyl polymer. Such compounds are disclosed in U.S. Patent 2,798,053, which is incorporated herein by reference. Methods for making carboxyvinyl polymers are also disclosed in Brown, and are also incorporated herein by reference.
A carboxyvinyl polymer is an interpolymer of a monomeric mixture comprising a monomeric olefinically unsaturated carboxylic acid, and from about 0.1% to about 10% by weight of the total monomers of a polyether of a polyhydric alcohol, which polyhydric alcohol contains at least four carbon atoms to which are attached at least three hydroxyl groups, the polyether containing more than one alkenyl group per molecule. Other monoolefinic monomeric materials may be present in the monomeric mixture if desired, even in predominant proportion. Carboxyvinyl polymers are substantially insoluble in liquid, volatile organic hydrocarbons and are dimensionally stable on exposure to air.
Preferred polyhydric alcohols used to produce carboxyvinyl polymers include polyols selected from the class consisting of oligosaccharides, reduced derivatives thereof in which the carbonyl group is converted to an alcohol group, and pentaerythritol; more preferred are oligosaccharides, most preferred is sucrose. It is preferred that the hydroxyl groups of the polyol which are modified be etherified with allyl groups, the polyol having at least two allyl ether groups per polyol molecule. When the polyol is sucrose, it is preferred that the sucrose have at least about five allyl ether groups per sucrose molecule. It is preferred that the polyether of the polyol comprise from about 0.1% to about 4% of the total monomers, more preferably from about 0.2% to about 2.5%.
Preferred monomeric olefinically unsaturated carboxylic acids for use in producing carboxyvinyl polymers used herein include monomeric, polymerizable, alpha-beta monoolefinically unsaturated lower aliphatic carboxylic acids; more preferred are monomeric monoolefinic acrylic acids of the structure

wherein R is a substituent selected from the group consisting of hydrogen and lower alkyl groups; most preferred is acrylic acid.
Carboxyvinyl polymers useful in formulations of the present invention have a molecular weight of at least about 750,000. Preferred are highly cross-linked carboxyvinyl polymers having a molecular weight of at least about 1,250,000. Also preferred are carboxyvinyl polymers having a molecular weight of at least about 3,000,000, which may be less highly cross-linked.
Various carboxyvinyl polymers are commercially available from B. F. Goodrich Company, New York, N.Y., under the trade name Carbopol. Carboxyvinyl polymers useful in formulations of the present invention include Carbopol 910 having a molecular weight of about 750,000; preferred is Carbopol 941 having a molecular weight of about 1,250,000, and more preferred are Carbopols 934 and 940 having molecular weights of about 3,000,000 and 4,000,000, respectively.
Carbopol 934 is a very slightly cross-linked carboxyvinyl polymer having a molecular weight of about 3,000,000. It has been described as a high molecular weight polyacrylic acid cross-linked with about 1% of polyallyl sucrose having an average of about 5.8 allyl groups for each molecule of sucrose.
Additional polycarboxylate polymers useful in the present invention are Sokolan PHC-25^R, a polyacrylic acid available from BASF Corp., and Gantrez^R a poly(methyl vinyl ether/maleic acid) interpolymer available from GAF Corp.
Preferred polycarboxylate polymers of the present invention are non-linear, water-dispersible, polyacrylic acid cross-linked with a polyalkenyl polyether and having a molecular weight of from about 750,000 to about 4,000,000.
Highly preferred examples of these polycarboxylate polymer thickeners are the Carbopol 600 series resins available from B. F. Goodrich. Especially preferred are Carbopol 616 and 617. It is believed that these resins are more highly cross-linked than the 900 series resins and have molecular weights between about 1,000,000 and 4,000,000. Mixtures of polycarboxylate polymers as herein described may also be used in the present invention. Particularly preferred is a mixture of Carbopol 616 and 617 series resins.
The polycarboxylate polymer thickener is utilized preferably with essentially no clay thickening agents. In fact, it has been found that if the polycarboxylate polymers of the present invention are utilized with clay in the composition of the present invention, a less desirable product, in terms of phase instability, results. In other words, the polycarboxylate polymer is preferably used instead of clay as a thickening/stabilizing agent in the present compositions.
The polycarboxylate polymer also provides a reduction in what is commonly called "bottle hang-up". This term refers to the inability to dispense all of the dishwashing detergent product from its container. Without intending to be bound by theory, it is believed that the thickened compositions of the present invention provide this benefit because the force of cohesion of the composition is greater than the force of adhesion to the container wall. With clay thickener systems, which most commercially available products contain, bottle hang-up can be a significant problem under certain conditions.
Without intending to be bound by theory, it is also believed that the long chain molecules of the polycarboxylate polymer thickener help suspend solids in the thickened detergent compositions of the present invention and help keep the matrix expanded. The polymeric material is also less sensitive than clay thickeners to destruction due to repeated shearing, such as occurs when the composition is vigorously mixed.
If the polycarboxylate polymer is used as a thickening agent in the compositions of the present invention, it is typically present at a level of from about 0.1% to about 10%, preferably from about 0.2% to about 2% by weight.
The thickening agents are used to provide a yield value of from about 50 to about 350 and most preferably from about 75 to about 250.

Yield Value Analysis

The yield value is an indication of the shear stress at which the gel strength is exceeded and flow is initiated. It is measured herein with a Brookfield RVT model viscometer with a T-bar B spindle at 25°C utilizing a Helipath drive upward during associated readings. The system is set to 0.5 rpm and a reading is taken for the composition to be tested after 30 seconds or after the system is stable. The system is stopped and the rpm is reset to 1.0 rpm. A reading is taken for the same composition after 30 seconds or after the system is stable. Stress at zero shear is equal to two times the 0.5 rpm reading minus the reading at 1.0 rpm. The yield value is calculated as the stress at zero shear times 18.8 (conversion factor).

Other Surfactants

Other surfactants, such as anionic, nonionic, ampholytic and zwitterionic surfactants may also be incorporated into the detergent compositions of the present invention.

Anionic Surfactants

One type of anionic surfactant which can be utilized encompasses alkyl ester sulfonates. Alkyl ester sulfonate surfactants hereof include linear esters of C₈-C₂₀ carboxylic acids (i.e., fatty acids) which are sulfonated with gaseous SO₃ according to "The Journal of the American Oil Chemists Society," 52 (1975), pp. 323-329. Suitable starting materials would include natural fatty substances as derived from tallow, palm oil, etc.
The preferred alkyl ester sulfonate surfactant, especially for laundry applications, comprise alkyl ester sulfonate surfactants of the structural formula:

wherein R³ is a C₈-C₂₀ hydrocarbyl, preferably an alkyl, or combination thereof, R⁴ is a C₁-C₆ hydrocarbyl, preferably an alkyl, or combination thereof, and M is a cation which forms a water soluble salt with the alkyl ester sulfonate. Suitable salt-forming cations include metals such as sodium, potassium, and lithium, and substituted or unsubstituted ammonium cations, such as monoethanolamine, diethanolamine, and triethanolamine. Preferably, R³ is C₁₄-C₁₆ alkyl, and R⁴ is methyl, ethyl or isopropyl. Especially preferred are the methyl ester sulfonates wherein R³ is C₁₄-C₁₆ alkyl.

Alkyl Sulfate Surfactant

Alkyl sulfate surfactants hereof are water soluble salts or acids of the formula ROSO₃M wherein R preferably is a C₁₀-C₂₄ hydrocarbyl, preferably an alkyl or hydroxyalkyl having a C₁₀-C₂₀ alkyl component, more preferably a C₁₂-C₁₈ alkyl or hydroxyalkyl, and M is H or a cation, e.g., an alkali metal cation (e.g., sodium, potassium, lithium), or ammonium or substituted ammonium (e.g., methyl-, dimethyl-, and trimethyl ammonium cations and quaternary ammonium cations such as tetramethylammonium and dimethyl piperdinium cations and quaternary ammonium cations derived from alkylamines such as ethylamine, diethylamine, triethylamine, and mixtures thereof, and the like). Typically, alkyl chains of C₁₂₋₁₆ are preferred for lower wash temperatures (e.g., below about 50°C) and C₁₄₋₁₈ alkyl chains are preferred for higher wash temperatures (e.g., above about 50°C).

Alkyl Alkoxylated Sulfate Surfactant

Alkyl alkoxylated sulfate surfactants hereof are water soluble salts or acids of the formula RO(A)_mSO₃M wherein R is an unsubstituted C₁₀-C₂₄ alkyl or hydroxyalkyl group having a C₁₀-C₂₄ alkyl component, preferably a C₁₂-C₂₀ alkyl or hydroxyalkyl, more preferably C₁₂-C₁₈ alkyl or hydroxyalkyl, A is an ethoxy or propoxy unit, m is greater than zero, typically between about 0.5 and about 6, more preferably between about 0.5 and about 3, and M is H or a cation which can be, for example, a metal cation (e.g., sodium, potassium, lithium, calcium, magnesium, etc.), ammonium or substituted-ammonium cation. Alkyl ethoxylated sulfates as well as alkyl propoxylated sulfates are contemplated herein. Specific examples of substituted ammonium cations include methyl-, dimethyl-, trimethyl-ammonium cations and quaternary ammonium cations such as tetramethyl-ammonium and dimethyl piperdinium cations and those derived from alkylamines such as ethylamine, diethylamine, triethylamine, mixtures thereof, and the like. Exemplary surfactants are C₁₂-C₁₈ alkyl polyethoxylate (1.0) sulfate (C₁₂-C₁₈E(1.0)M), C₁₂-C₁₈ alkyl polyethoxylate (2.25) sulfate (C₁₂-C₁₈E(2.25)M), C₁₂-C₁₈ alkyl polyethoxylate (3.0) sulfate (C₁₂-C₁₈E(3.0)M), and C₁₂-C₁₈ alkyl polyethoxylate (4.0) sulfate (C₁₂-C₁₈E(4.0)M), wherein M is conveniently selected from sodium and potassium.

Other Anionic Surfactants

Other anionic surfactants useful for detersive purposes can also be included in the compositions hereof. These can include salts (including, for example, sodium, potassium, ammonium, and substituted ammonium salts such as mono-, di- and triethanolamine salts) of soap, C₉-C₂₀ linear alkylbenzenesulfonates, C₈-C₂₂ primary or secondary alkanesulfonates, C₈-C₂₄ olefinsulfonates, sulfonated polycarboxylic acids prepared by sulfonation of the pyrolyzed product of alkaline earth metal citrates, e.g., as described in British patent specification No. 1,082,179, C₈-C₂₄ alkylpolyglycolethersulfates (containing up to 10 moles of ethylene oxide); alkyl glycerol sulfonates, fatty acyl glycerol sulfonates, fatty oleyl glycerol sulfates, alkyl phenol ethylene oxide ether sulfates, paraffin sulfonates, alkyl phosphates, isethionates such as the acyl isethionates, acyl taurates, fatty acid amides of methyl tauride, alkyl succinamates and sulfosuccinates, monoesters of sulfosuccinates (especially saturated and unsaturated C₁₂-C₁₈ monoesters), diesters of sulfosuccinates (especially saturated and unsaturated C₆-C₁₂ diesters), acyl sarcosinates, sulfates of alkylpolysaccharides such as the sulfates of alkylpolyglucoside (the nonionic nonsulfated compounds being described below), C₉-C₁₇ acyl-N-(C₁-C₄ alkyl) or -N-(C₂-C₄ hydroxyalkyl) glucamine sulfates, branched primary alkyl sulfates, and fatty acids esterified with isethionic acid and neutralized with sodium hydroxide. Resin acids and hydrogenated resin acids are also suitable, such as rosin, hydrogenated rosin, and resin acids and hydrogenated resin acids present in or derived from tall oil. Further examples are described in "Surface Active Agents and Detergents" (Vol. I and II by Schwartz, Perry and Berch). A variety of such surfactants are also generally disclosed in U.S. Patent 3,929,678, issued December 30, 1975 to Laughlin, et al. at Column 23, line 58 through Column 29, line 23 (herein incorporated by reference).

Nonionic Detergent Surfactants

Suitable nonionic detergent surfactants are generally disclosed in U.S. Patent 3,929,678, Laughlin et al., issued December 30, 1975, at column 13, line 14 through column 16, line 6, incorporated herein by reference. Exemplary, non-limiting classes of useful nonionic surfactants are listed below.

1. The polyethylene, polypropylene, and polybutylene oxide condensates of alkyl phenols. In general, the polyethylene oxide condensates are preferred. These compounds include the condensation products of alkyl phenols having an alkyl group containing from about 6 to about 12 carbon atoms in either a straight chain or branched chain configuration with the alkylene oxide. In a preferred embodiment, the ethylene oxide is present in an amount equal to from about 5 to about 25 moles of ethylene oxide per mole of alkyl phenol. Commercially available nonionic surfactants of this type include Igepal^TM CO-630, marketed by the GAF Corporation; and Triton^TM X-45, X-114, X-100, and X-102, all marketed by the Rohm & Haas Company.
2. The condensation products of aliphatic alcohols with from about 1 to about 25 moles of ethylene oxide. The alkyl chain of the aliphatic alcohol can either be straight or branched, primary or secondary, and generally contains from about 8 to about 22 carbon atoms. Particularly preferred are the condensation products of alcohols having an alkyl group containing from about 10 to about 20 carbon atoms with from about 2 to about 10 moles of ethylene oxide per mole of alcohol. Examples of commercially available nonionic surfactants of this type include Tergitol^TM 15-S-9 (the condensation product of C₁₁-C₁₅ linear alcohol with 9 moles ethylene oxide), Tergitol^TM 24-L-6 NMW (the condensation product of C₁₂-C₁₄ primary alcohol with 6 moles ethylene oxide with a narrow molecular weight distribution), both marketed by Union Carbide Corporation; Neodol^TM 45-9 (the condensation product of C₁₄-C₁₅ linear alcohol with 9 moles of ethylene oxide), Neodol^TM 23-6.5 (the condensation product of C₁₂-C₁₃ linear alcohol with 6.5 moles of ethylene oxide), Neodol^TM 45-7 (the condensation product of C₁₄-C₁₅ linear alcohol with 7 moles of ethylene oxide), Neodol^TM 45-4 (the condensation product of C₁₄-C₁₅ linear alcohol with 4 moles of ethylene oxide), marketed by Shell Chemical Company, and Kyro^TM EOB (the condensation product of C₁₃-C₁₅ alcohol with 9 moles ethylene oxide), marketed by The Procter & Gamble Company.
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 preferably has a molecular weight of from about 1500 to about 1800 and 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% of the total weight of the condensation product, which corresponds to condensation with up to about 40 moles of ethylene oxide. Examples of compounds of this type include certain of the commercially-available Pluronic^TM surfactants, marketed by BASF.
4. The condensation products of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylenediamine. The hydrophobic moiety of these products consists of the reaction product of ethylenediamine and excess propylene oxide, and generally has a molecular weight of from about 2500 to about 3000. This hydrophobic moiety is condensed with ethylene oxide to the extent that the condensation product contains from about 40% to about 80% 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 TetronicTM compounds, marketed by BASF.
5. Semi-polar nonionic surfactants are a special category of nonionic surfactants which include water-soluble amine oxides containing one alkyl moiety of from about 10 to about 18 carbon atoms and 2 moieties selected from the group consisting of alkyl groups and hydroxyalkyl groups containing from about 1 to about 3 carbon atoms; water-soluble phosphine oxides containing one alkyl moiety of from about 10 to about 18 carbon atoms and 2 moieties selected from the group consisting of alkyl groups and hydroxyalkyl groups containing from about 1 to about 3 carbon atoms; and water-soluble sulfoxides containing one alkyl moiety of from about 10 to about 18 carbon atoms and a moiety selected from the group consisting of alkyl and hydroxyalkyl moieties of from about 1 to about 3 carbon atoms.
Semi-polar nonionic detergent surfactants include the amine oxide surfactants having the formula
wherein R³ is an alkyl, hydroxyalkyl, or alkyl phenyl group or mixtures thereof containing from about 8 to about 22 carbon atoms; R⁴ is an alkylene or hydroxyalkylene group containing from about 2 to about 3 carbon atoms or mixtures thereof; x is from 0 to about 3; and each R⁵ is an alkyl or hydroxyalkyl group containing from about 1 to about 3 carbon atoms or a polyethylene oxide group containing from about 1 to about 3 ethylene oxide groups. The R⁵ groups can be attached to each other, e.g., through an oxygen or nitrogen atom, to form a ring structure.
These amine oxide surfactants in particular include C₁₀-C₁₈ alkyl dimethyl amine oxides and C₈-C₁₂ alkoxy ethyl dihydroxy ethyl amine oxides.
6. Alkylpolysaccharides disclosed in U.S. Patent 4,565,647, Llenado, issued January 21, 1986, having a hydrophobic group containing from about 6 to about 30 carbon atoms, preferably from about 10 to about 16 carbon atoms and a polysaccharide, e.g., a polyglycoside, hydrophilic group containing from about 1.3 to about 10, preferably from about 1.3 to about 3, most preferably from about 1.3 to about 2.7 saccharide units. Any reducing saccharide containing 5 or 6 carbon atoms can be used, e.g., glucose, galactose and galactosyl moieties can be substituted for the glucosyl moieties. (Optionally the hydrophobic group is attached at the 2-, 3-, 4-, etc. positions thus giving a glucose or galactose as opposed to a glucoside or galactoside.) The intersaccharide bonds can be, e.g., between the one position of the additional saccharide units and the 2-, 3-, 4-, and/or 6- positions on the preceding saccharide units.
Optionally, and less desirably, there can be a polyalkyleneoxide chain joining the hydrophobic moiety and the polysaccharide moiety. The preferred alkyleneoxide is ethylene oxide. Typical hydrophobic groups include alkyl groups, either saturated or unsaturated, branched or unbranched containing from about 8 to about 18, preferably from about 10 to about 16, carbon atoms. Preferably, the alkyl group is a straight chain saturated alkyl group. The alkyl group can contain up to about 3 hydroxy groups and/or the polyalkyleneoxide chain can contain up to about 10, preferably less than 5, alkyleneoxide moieties. Suitable alkyl polysaccharides are octyl, nonyldecyl, undecyldodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl, di-, tri-, tetra-, penta-, and hexaglucosides, galactosides, lactosides, glucoses, fructosides, fructoses and/or galactoses. Suitable mixtures include coconut alkyl, di-, tri-, tetra-, and pentaglucosides and tallow alkyl tetra-, penta-, and hexaglucosides.
The preferred alkylpolyglycosides have the formula

R²O(C_nH_2nO)_t(glycosyl)_x

wherein R² is selected from the group consisting of alkyl, alkylphenyl, hydroxyalkyl, hydroxyalkylphenyl, and mixtures thereof in which the alkyl groups contain from about 10 to about 18, preferably from about 12 to about 14, carbon atoms; n is 2 or 3, preferably 2; t is from 0 to about 10, preferably 0; and x is from about 1.3 to about 10, preferably from about 1.3 to about 3, most preferably from about 1.3 to about 2.7. The glycosyl is preferably derived from glucose. To prepare these compounds, the alcohol or alkylpolyethoxy alcohol is formed first and then reacted with glucose, or a source of glucose, to form the glucoside (attachment at the 1-position). The additional glycosyl units can then be attached between their 1-position and the preceding glycosyl units 2-, 3-, 4- and/or 6-position, preferably predominately the 2-position.
7. Fatty acid amide surfactants having the formula:
wherein R⁶ is an alkyl group containing from about 7 to about 21 (preferably from about 9 to about 17) carbon atoms and each R⁷ is selected from the group consisting of hydrogen, C₁-C₄ alkyl, C₁-C₄ hydroxyalkyl, and -(C₂H₄O)_xH where x varies from about 1 to about 3.

Preferred amides are C₈-C₂₀ ammonia amides, monoethanolamides, diethanolamides, and isopropanolamides.

Ampholytic Surfactants

Ampholytic surfactants can be incorporated into the detergent compositions hereof. These surfactants can be broadly described as aliphatic derivatives of secondary or tertiary amines, or aliphatic derivatives of heterocyclic secondary and tertiary amines in which the aliphatic radical can be straight chain or branched. One of the aliphatic substituents contains at least 8 carbon atoms, typically from 8 to 18 carbon atoms, and at least one contains an anionic water-solubilizing group, e.g., carboxy, sulfonate, sulfate. See U.S. Patent No. 3,929,678 to Laughlin et al., issued December 30, 1975 at column 19, lines 18-35 (herein incorporated by reference) for examples of ampholytic surfactants.

Zwitterionic Surfactants

Zwitterionic surfactants can also be incorporated into the detergent compositions hereof. These surfactants can be broadly described as derivatives of secondary and tertiary amines, derivatives of heterocyclic secondary and tertiary amines, or derivatives of quaternary ammonium, quaternary phosphonium or tertiary sulfonium compounds. See U.S. Patent No. 3,929,678 to Laughlin et al., issued December 30, 1975 at column 19, line 38 through column 22, line 48 (herein incorporated by reference) for examples of zwitterionic surfactants.
Ampholytic and zwitterionic surfactants are generally used in combination with one or more anionic and/or nonionic surfactants.
Preferred additional surfactants are anionic and nonionic surfactants, with C₁₁₋₂₇ alkyl ester sulfonates, C₈₋₂₂ primary and secondary alkane sulfonates, C₁₀₋₁₈ alkyl dimethyl amine oxides, alkylpolysaccharides, and mixtures thereof being most preferred.
If included in the compositions of the present invention, these optional additional surfactants are typically present at a concentration of from about 1.0% to about 10%, preferably from about 2% to about 5% by weight.

Other Optional Ingredients

Other optional ingredients include detergency builders, either of the organic or inorganic type, although such builders in general are not preferred for use in the composition of the present invention. Examples of water-soluble inorganic builders which can be used, either alone or in admixture with themselves or with organic alkaline sequestrant builder salts, are glycine, alkyl and alkenyl succinates, alkali metal carbonates, phosphates, polyphosphates, and silicates. Specific examples of such salts are sodium tripolyphosphate, sodium carbonate, potassium carbonate, sodium pyrophosphate, potassium pyrophosphate, potassium tripolyphosphate, and sodium hexametaphosphate. 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, examples of which include, but are not limited to, water-soluble citrates such as sodium and potassium citrate, sodium and potassium tartrate, sodium and potassium ethylenediaminetetraacetate, sodium and potassium N-(2-hydroxyethyl)-ethylene diamine triacetates, sodium and potassium nitrilo triacetates, sodium and potassium N-(2-hydroxy- ethyl)-nitrilo diacetates , sodium and potassium oxydisuccinates, and sodium and potassium tartrate mono- and disuccinates, such as those described in U.S. Patent 4,663,071 (Bush et al., issued May 5, 1987), the disclosure of which is incorporated herein. Other organic detergency builders, such as water-soluble phosphonates, can be used in the compositions of the present invention. However, detergency builders in general have limited value when the compositions of the present invention are in the form of light-duty liquid dishwashing detergent compositions. If included in the compositions of the present invention, these optional builders are typically present at a concentration of from about 1.0% to about 10%, preferably from about 2% to about 5% by weight.
Other desirable ingredients include diluents, solvents, dyes, perfumes and hydrotropes (preferred). Diluents can be inorganic salts, such as sodium and potassium sulfate, ammonium chloride, sodium and potassium chloride, sodium bicarbonate, etc. Diluents useful in the compositions of the present invention are typically present at levels of from about 1% to about 10%, preferably from about 2% to about 5% by weight.
Solvents useful herein include water and lower molecular weight alcohols, such as ethyl alcohol, isopropyl alcohol, etc. Solvents useful in the compositions of the present invention are typically present at levels of from about 1% to about 60%, preferably from about 5% to about 50% by weight.
Hydrotropes such as sodium and potassium toluene sulfonate, sodium and potassium xylene sulfonate, sodium and potassium cumene sulfonate, trisodium and tripotassium sulfosuccinate, and related compounds (as disclosed in U.S. Patent 3,915,903, the disclosure of which is incorporated herein) can be utilized in the interests of achieving a desired product phase stability and viscosity. It has been found that the hydrotropes can have a positive effect on the suds benefit of the present invention. While not intending to be bound by theory, it is believed that this benefit is due to the viscosity characteristics of such hydrotropes. Hydrotropes useful in the compositions of the present invention are typically present at a level of from about 1% to about 10% by weight, preferably from about 2% to about 5% by weight.
The claimed compositions of the present invention are beneficial in that they provide unexpected improved sudsing performance when the particular polyhydroxy fatty acid amide is combined with the alkyl ethoxy carboxylate. While not intending to be bound by theory, it is believed that the compositions of the present invention offer the additional benefits of improved cleaning performance and are mild to the skin, even when formulated as a liquid and having a high alkaline pH. Again, while not intending to be bound by theory, it is further believed that an additional benefit of the compositions of the present invention is that they clean dishes without imparting a "greasy" feel to the finish product. This is especially important in consumer markets where the cleanliness of a dish is judged by the lack of such a "greasy" feel. Additionally, it is believed that the compositions of the present invention offer the further benefit of a reduced "slippery" feel typically associated with detergent compositions. This is especially important in consumer markets where such a feeling is not favored and is viewed as incomplete rinsing of surfactants from the dish surface.
In the method aspect of this invention, soiled dishes are contacted with an effective amount, typically from about 0.5 ml. to about 20 ml. (per 25 dishes being treated), preferably from about 3 ml. to about 10 ml., of the composition of the present invention. The actual amount of liquid detergent composition used will be based on the judgement of user, and will typically depend upon factors such as the particular product formulation of the composition, including the concentration of active ingredient in the composition, the number of soiled dishes to be cleaned, the degree of soiling on the dishes, and the like. The particular product formulation, in turn, will depend upon a number of factors, such as the intended market (i.e., U.S., Europe, Japan, etc.) for the composition product. The following are examples of typical methods in which the detergent compositions of the present invention may be used to clean soiled dishes. These examples are for illustrative purposes and are not intended to be limiting.
In a typical U.S. application, from about 3 ml. to about 15 ml., preferably from about 5 ml. to about 10 ml. of a liquid detergent composition is combined with from about 1,000 ml. to about 10,000 ml., more typically from about 3,000 ml. to about 5,000 ml. of water in a sink having a volumetric capacity in the range of from about 5,000 ml. to about 20,000 ml., more typically from about 10,000 ml. to about 15,000 ml. The detergent composition has a surfactant mixture concentration of from about 21% to about 44% by weight, preferably from about 25% to about 40% by weight. The soiled dishes are immersed in the sink containing the detergent composition and water, where they are cleaned by contacting the soiled surface of the dish with a cloth, sponge, or similar article. The cloth, sponge, or similar article may be immersed in the detergent composition and water mixture prior to being contacted with the dish surface, and is typically contacted with the dish surface for a period of time ranging from about 1 to about 10 seconds, although the actual time will vary with each application and user. The contacting of the cloth, sponge, or similar article to the dish surface is preferably accompanied by a concurrent scrubbing of the dish surface.
In a typical European market application, from about 3 ml. to about 15 ml. preferably from about 3 ml. to about 10 ml. of a liquid detergent composition is combined with from about 1,000 ml. to about 10,000 ml., preferably from about 3,000 ml. to about 5,000 ml. of water in a sink having a volumetric capacity in the range of from about 5,000 ml. to about 20,000 ml., more typically from about 10,000 ml. to about 15,000 ml. The detergent composition has a surfactant mixture concentration of from about 21% to about 44% by weight, preferably from about 25% to about 35% by weight. The soiled dishes are immersed in the sink containing the detergent composition and water, where they are cleaned by contacting the soiled surface of the dish with a cloth, sponge, or similar article. The cloth, sponge, or similar article may be immersed in the detergent composition and water mixture prior to being contacted with the dish surface, and is typically contacted with the dish surface for a period of time ranging from about 1 to about 10 seconds, although the actual time will vary with each application and user. The contacting of the cloth, sponge, or similar article to the dish surface is preferably accompanied by a concurrent scrubbing of the dish surface.
In a typical Latin American and Japanese market application, from about 1 ml. to about 50 ml., preferably from about 2 ml. to about 10 ml. of a composition is combined with from about 50 ml. to about 2,000 ml., more typically from about 100 ml. to about 1,000 ml. of water in a bowl having a volumetric capacity in the range of from about 500 ml. to about 5,000 ml., more typically from about 500 ml. to about 2,000 ml. The detergent composition has a surfactant mixture concentration of from about 5% to about 40% by weight, preferably from about 10% to about 30% by weight. The soiled dishes are cleaned by contacting the soiled surface of the dish with a cloth, sponge, or similar article. The cloth, sponge, or similar article may be immersed in the detergent composition and water mixture prior to being contacted with the dish surface, and is typically contacted with the dish surface for a period of time ranging from about 1 to about 10 seconds, although the actual time will vary with each application and user. The contacting of the cloth, sponge, or similar article to the dish surface is preferably accompanied by a concurrent scrubbing of the dish surface.
Another method of use will comprise immersing the soiled dishes into a water bath which is absent any liquid dishwashing detergent. A device for absorbing liquid dishwashing detergent, such as a sponge, is placed directly into a separate quantity of undiluted liquid dishwashing composition for a period of time typically ranging from about 1 to about 5 seconds. The absorbing device, and consequently the undiluted liquid dishwashing composition, is then contacted individually to the surface of each of the soiled dishes to remove said soiling. The absorbing device is typically contacted with each dish surface for a period of time range from about 1 to about 10 seconds, although the actual time of application will be dependent upon factors such as the degree of soiling of the dish. The contacting of the absorbing device to the dish surface is preferably accompanied by concurrent scrubbing.

EXPERIMENTAL

This exemplifies a process for making a N-methyl, 1-deoxyglucityl lauramide surfactant for use herein. Although a skilled chemist can vary apparatus configuration, one suitable apparatus for use herein comprises a three-liter four-necked flask fitted with a motor-driven paddle stirrer and a thermometer of length sufficient to contact the reaction medium. The other two necks of the flask are fitted with a nitrogen sweep and a wide-bore side-arm (caution: a wide-bore side-arm is important in case of very rapid methanol evolution) to which is connected an efficient collecting condenser and vacuum outlet. The latter is connected to a nitrogen bleed and vacuum gauge, then to an aspirator and a trap. A 500 watt heating mantle with a variable transformer temperature controller ("Variac") used to heat the reaction is so placed on a lab-jack that it may be readily raised or lowered to further control temperature of the reaction.
N-methylglucamine (195 g., 1.0 mole, Aldrich, M4700-0) and methyl laurate (Procter & Gamble CE 1270, 220.9 g., 1.0 mole) are placed in a flask. The solid/liquid mixture is heated with stirring under a nitrogen sweep to form a melt (approximately 25 minutes). When the melt temperature reaches 145° C, catalyst (anhydrous powdered sodium carbonate, 10.5 g., 0.1 mole, J. T. Baker) is added. The nitrogen sweep is shut off and the aspirator and nitrogen bleed are adjusted to give 5 inches (5/31 atm.) Hg. vacuum. From this point on, the reaction temperature is held at 150° C by adjusting the Variac and/or by raising or lowering the mantle.
Within 7 minutes, first methanol bubbles are sighted at- the meniscus of the reaction mixture. A vigorous reaction soon follows. Methanol is distilled over until its rate subsides. The vacuum is adjusted to give about 10 inches Hg. (10/31 atm.) vacuum. The vacuum is increased approximately as follows (in inches Hg. at minutes): 10 at 3, 20 at 7, 25 at 10. 11 minutes from the onset of methanol evolution, heating and stirring are discontinued coincident with some foaming. The product is cooled and solidifies.
The following examples are meant to exemplify compositions of the present invention, but are not necessarily meant to limit or otherwise define the scope of the invention, said scope being determined according to claims which follow.

EXAMPLES

The following examples illustrate the practice of the present invention, but are not intended to be limiting thereof.

EXAMPLE I

The following three formulations A, B and C of the present invention are prepared according to the description set forth below:
Formulation A is made by initially combining an alkyl ethoxy carboxylate detergent mixture with a C₁₂₋₁₄ fatty acid N-methyl glucamide to form a mixture. Ethanol, sodium chloride and sodium xylene sulfonate are then added to this mixture. Any desired remaining surfactants are then added. Glycine is added and the pH is adjusted to about 9.0 with sodium hydroxide. Finally, magnesium chloride is added, which reduces the pH accordingly. Final viscosity and pH adjustments can be made at this time, followed by the addition of perfume and dye. The balance is water.
Formulation B is made by adding ethanol, sodium chloride and sodium xylene sulfonate to an alkyl ethoxy carboxylate detergent/polyhydroxy fatty acid amide mixture of the type prepared in Formulation A. The remaining formula components are added in the order given in the table below.
Formulation C is made by adding ethanol, sodium chloride and sodium xylene sulfonate to an alkyl ethoxy carboxylate detergent/polyhydroxy fatty acid amide mixture of the type prepared in Formulation A. C₁₂₋₁₄ monoethanol amide is warmed to about 65°C and is then added to the mixture. Minor pH and viscosity adjustments are made at this time, followed by the addition of dye, perfume and water to bring the formulation to 100%.
In the above formulations of Example I, the surfactant portion contains about 93.9% alkyl ethoxy carboxylates of the formula RO(CH₂CH₂O)_xCH₂COO⁻Na⁺, wherein R is a C₁₂₋₁₃ alkyl averaging 12.5, x ranges from 0 to about 10, and the ethoxylate distribution is such that the amount of material where x is 0 is about 2.8% and the amount of material where x is greater than 7 is less than about 2% by weight of the alkyl ethoxy carboxylates. The average x in the distribution is 2.8. The surfactant mixture also contains about 6.1% of alcohol ethoxylates of the formula RO(CH₂CH₂O)_xH with R being a C₁₂₋₁₃ alkyl averaging 12.5 and the average x = 2.8. The surfactant mixture contains 0% soap materials.

EXAMPLE II

The following three formulations C, D and E of the present invention are prepared in the same manner as the formulations of

Example I:

EXAMPLE III

An alternate method for preparing the polyhydroxy fatty acid amides used herein is as follows. A reaction mixture consisting of 84.87g. fatty acid methyl ester (source: Procter & Gamble methyl ester CE1270), 75g. N-methyl-D-glucamine (source: Aldrich Chemical Company M4700-0), 1.04g. sodium methoxide (source: Aldrich Chemical Company 16,499-2), and 68.51g. methyl alcohol is used. The reaction vessel comprises a standard reflux set-up fitted with a drying tube, condenser and stir bar. In this procedure, the N-methyl glucamine is combined with methanol with stirring under argon and heating is begun with good mixing (stir bar; reflux). After 15-20 minutes, when the solution has reached the desired temperature, the ester and sodium methoxide catalyst are added. Samples are taken periodically to monitor the course of the reaction, but it is noted that the solution is completely clear by 63.5 minutes. It is judged that the reaction is, in fact, nearly complete at that point. The reaction mixture is maintained at reflux for 4 hours. After removal of the methanol, the recovered crude product weighs 156.16 grams. After vacuum drying and purification, an overall yield of 106.92 grams purified product is recovered. However, percentage yields are not calculated on this basis, inasmuch as regular sampling throughout the course of the reaction makes an overall percentage yield value meaningless.
The following is not intended to limit the invention herein, but is simply to further illustrate additional aspects of the technology which may be considered by the formulator in the manufacture of a wide variety of detergent compositions using the polyhydroxy fatty acid amides.
It will be readily appreciated that the polyhydroxy fatty acid amides are, by virtue of their amide bond, subject to some instability under highly basic or highly acidic conditions. While some decomposition can be tolerated, it is preferred that these materials not be subjected to pH's above about 11, preferably 10, nor below about 3 for unduly extended periods. Final product pH (liquids) is typically 7.0-9.0.
During the manufacture of the polyhydroxy fatty acid amides it will typically be necessary to at least partially neutralize the base catalyst used to form the amide bond. While any acid can be used for this purpose, the detergent formulator will recognize that it is a simple and convenient matter to use an acid which provides an anion that is otherwise useful and desirable in the finished detergent composition. For example, citric acid can be used for purposes of neutralization and the resulting citrate ion (ca. 1%) be allowed to remain with a ca. 40% polyhydroxy fatty acid amide slurry and be pumped into the later manufacturing stages of the overall detergent-manufacturing process. The acid forms of materials such as oxydisuccinate, nitrilotriacetate, ethylenediaminetetraacetate, tartrate/succinate, and the like, can be used similarly.
The polyhydroxy fatty acid amides derived from coconut alkyl fatty acids (predominantly C₁₂-C₁₄) are more soluble than their tallow alkyl (predominantly C₁₆-C₁₈) counterparts. Accordingly, the C₁₂-C₁₄ materials are somewhat easier to formulate in liquid compositions, and are more soluble in cool-water laundering baths. However, the C₁₆-C₁₈ materials are also quite useful, especially under circumstances where warm-to-hot wash water is used. Indeed, the C₁₆-C₁₈ materials may be better detersive surfactants than their C₁₂-C₁₄ counterparts. Accordingly, the formulator may wish to balance ease-of-manufacture vs. performance when selecting a particular polyhydroxy fatty acid amide for use in a given formulation.
It will also be appreciated that the solubility of the polyhydroxy fatty acid amides can be increased by having points of unsaturation and/or chain branching in the fatty acid moiety. Thus, materials such as the polyhydroxy fatty acid amides derived from oleic acid and iso-stearic acid are more soluble than their n-alkyl counterparts.
Likewise, the solubility of polyhydroxy fatty acid amides prepared from disaccharides, trisaccharides, etc., will ordinarily be greater than the solubility of their monosaccharide-derived counterpart materials. This higher solubility can be of particular assistance when formulating liquid compositions. Moreover, the polyhydroxy fatty acid amides wherein the polyhydroxy group is derived from maltose appear to function especially well as detergents when used in combination with conventional alkylbenzene sulfonate ("LAS") surfactants. While not intending to be limited by theory, it appears that the combination of LAS with the polyhydroxy fatty acid amides derived from the higher saccharides such as maltose causes a substantial and unexpected lowering of interfacial tension in aqueous media, thereby enhancing net detergency performance. (The manufacture of a polyhydroxy fatty acid amide derived from maltose is described hereinafter.)
The polyhydroxy fatty acid amides can be manufactured not only from the purified sugars, but also from hydrolyzed starches, e.g., corn starch, potato starch, or any other convenient plant-derived starch which contains the mono-, di-, etc. saccharide desired by the formulator. This is of particular importance from the economic standpoint. Thus, "high glucose" corn syrup, "high maltose" corn syrup, etc. can conveniently and economically be used. De-lignified, hydrolyzed cellulose pulp can also provide a raw material source for the polyhydroxy fatty acid amides.
As noted above, polyhydroxy fatty acid amides derived from the higher saccharides, such as maltose, lactose, etc., are more soluble than their glucose counterparts. Moreover, it appears that the more soluble polyhydroxy fatty acid amides can help solubilize their less soluble counterparts, to varying degrees. Accordingly, the formulator may elect to use a raw material comprising a high glucose corn syrup, for example, but to select a syrup which contains a modicum of maltose (e.g., 1% or more). The resulting mixture of polyhydroxy fatty acids will, in general, exhibit more preferred solubility properties over a broader range of temperatures and concentrations than would a "pure" glucose-derived polyhydroxy fatty acid amide. Thus, in addition to any economic advantages for using sugar mixtures rather than pure sugar reactants, the polyhydroxy fatty acid amides prepared from mixed sugars can offer very substantial advantages with respect to performance and/or ease-of-formulation. In some instances, however, some loss of grease removal performance (dishwashing) may be noted at fatty acid malt-amide levels above about 25% and some loss in sudsing above about 33% (said percentages being the percentage of maltamide-derived polyhydroxy fatty acid amide vs. glucose-derived polyhydroxy fatty acid amide in the mixture). This can vary somewhat, depending on the chain length of the fatty acid moiety. Typically, then, the formulator electing to use such mixtures may find it advantageous to select polyhydroxy fatty acid amide mixtures which contain ratios of monosaccharides (e.g., glucose) to di- and higher saccharides (e.g., maltose) from about 4:1 to about 99:1.
The manufacture of preferred uncyclized polyhydroxy fatty acid amides from fatty esters and N-alkyl polyols can be carried out in alcohol solvents at temperatures from about 30°C to 90°C, preferably about 50°C-80°C. It has now been determined that it may be convenient for the formulator of, for example, liquid detergents to conduct such processes in 1,2-propylene glycol solvent, since the glycol solvent need not be completely removed from the reaction product prior to use in the finished detergent formulation. Likewise, the formulator of, for example, solid, typically granular, detergent compositions may find it convenient to run the process at 30°C-90°C in solvents which comprise ethoxylated alcohols, such as the ethoxylated (EO 3-8) C₁₂-C₁₄ alcohols, such as those available as NEODOL 23 EO6.5 (Shell). When such ethoxylates are used, it is preferred that they not contain substantial amounts of unethoxylated alcohol and, most preferably, not contain substantial amounts of mono-ethoxylated alcohol. ("T" designation.)
While methods for making polyhydroxy fatty acid amides per se form no part of the invention herein, the formulator can also note other syntheses of polyhydroxy fatty acid amides as described hereinafter.
Typically, the industrial scale reaction sequence for preparing the preferred acyclic polyhydroxy fatty acid amides will comprise: Step 1 - preparing the N-alkyl polyhydroxy amine derivative from the desired sugar or sugar mixture by formation of an adduct of the N-alkyl amine and the sugar, followed by reaction with hydrogen in the presence of a catalyst; followed by Step 2 - reacting the aforesaid polyhydroxy amine with, preferably, a fatty ester to form an amide bond. While a variety of N-alkyl polyhydroxy amines useful in Step 2 of the reaction sequence can be prepared by various art-disclosed processes, the following process is convenient and makes use of economical sugar syrup as the raw material. It is to be understood that, for best results when using such syrup raw materials, the manufacturer should select syrups that are quite light in color or, preferably, nearly colorless ("water-white").

Preparation of N-Alkyl Polyhydroxy Amine From Plant-Derived Sugar Syrup

I. Adduct Formation - The following is a standard process in which about 420 g of about 55% glucose solution (corn syrup - about 231 g glucose - about 1.28 moles) having a Gardner Color of less than 1 is reacted with about 119 g of about 50% aqueous methylamine (59.5 g of methylamine - 1.92 moles) solution. The methylamine (MMA) solution is purged and shielded with N₂ and cooled to about 10°C, or less. The corn syrup is purged and shielded with N₂ at a temperature of about 10°-20°C. The corn syrup is added slowly to the MMA solution at the indicated reaction temperature as shown. The Gardner Color is measured at the indicated approximate times in minutes.
As can be seen from the above data, the Gardner Color for the adduct is much worse as the temperature is raised above about 30°C and at about 50°C, the time that the adduct has a Gardner Color below 7 is only about 30 minutes. For longer reaction, and/or holding times, the temperature should be less than about 20°C. The Gardner Color should be less than about 7, and preferably less than about 4 for good color glucamine.
When one uses lower temperatures for forming the adduct, the time to reach substantial equilibrium concentration of the adduct is shortened by the use of higher ratios of amine to sugar. With the 1.5:1 mole ratio of amine to sugar noted, equilibrium is reached in about two hours at a reaction temperature of about 30°C. At a 1.2:1 mole ratio, under the same conditions, the time is at least about three hours. For good color, the combination of amine:sugar ratio; reaction temperature; and reaction time is selected to achieve substantially equilibrium conversion, e.g., more than about 90%, preferably more than about 95%, even more preferably more than about 99%, based upon the sugar, and a color that is less than about 7, preferably less than about 4, more preferably less than about 1, for the adduct.
Using the above process at a reaction temperature of less than about 20°C and corn syrups with different Gardner Colors as indicated, the MMA adduct color (after substantial equilibrium is reached in at least about two hours) is as indicated.
As can be seen from the above, the starting sugar material must be very near colorless in order to consistently have adduct that is acceptable. When the sugar has a Gardner Color of about 1, the adduct is sometimes acceptable and sometimes not acceptable. When the Gardner Color is above 1 the resulting adduct is unacceptable. The better the initial color of the sugar, the better is the color of the adduct.
II. Hydrogen Reaction - Adduct from the above having a Gardner Color of 1 or less is hydrogenated according to the following procedure.
About 539 g of adduct in water and about 23.1 g of United Catalyst G49B Ni catalyst are added to a one liter autoclave and purged two times with 14.06 bar (200 psig) H₂ at about 20°C. The H₂ pressure is raised to about 98.45 bar (1400 psi) and the temperature is raised to about 50°C. The pressure is then raised to about 112.52 bar (1600 psig) and the temperature is held at about 50-55°C for about three hours. The product is about 95% hydrogenated at this point. The temperature is then raised to about 85°C for about 30 minutes and the reaction mixture is decanted and the catalyst is filtered out. The product, after removal of water and MMA by evaporation, is about 95% N-methyl glucamine, a white powder.
The above procedure is repeated with about 23.1 g of Raney Ni catalyst with the following changes. The catalyst is washed three times and the reactor, with the catalyst in the reactor, is purged twice with 14.06 bar (200 psig) H₂ and the reactor is pressurized with H₂ at 112.52 bar (1600 psig) for two hours, the pressure is released at one hour and the reactor is repressurized to 112.52 bar (1600 psig). The adduct is then pumped into the reactor which is at 14.06 bar (200 psig) and 20°C, and the reactor is purged with 14.06 bar (200 psig) H₂, etc., as above.
The resulting product in each case is greater than about 95% N-methyl glucamine; has less than about 10 ppm Ni based upon the glucamine; and has a solution color of less than about Gardner 2.
The crude N-methyl glucamine is color stable to about 140°C for a short exposure time.
It is important to have good adduct that has low sugar content (less than about 5%, preferably less than about 1%) and a good color (less than about 7, preferably less than about 4 Gardner, more preferably less than about 1).
In another reaction, adduct is prepared starting with about 159 g of about 50% methylamine in water, which is purged and shielded with N₂ at about 10-20°C. About 330 g of about 70% corn syrup (near water-white) is degassed with N₂ at about 50°C and is added slowly to the methylamine solution at a temperature of less than about 20°C. The solution is mixed for about 30 minutes to give about 95% adduct that is a very light yellow solution.
About 190 g of adduct in water and about 9 g of United Catalyst G49B Ni catalyst are added to a 200 ml autoclave and purged three times with H₂ at about 20°C. The H₂ pressure is raised to about 14.06 bar (200 psi) and the temperature is raised to about 50°C. The pressure is raised to 17.58 bar (250 psi) and the temperature is held at about 50-55°C for about three hours. The product, which is about 95% hydrogenated at this point, is then raised to a temperature of about 85°C for about 30 minutes and the product, after removal of water and evaporation, is about 95% N-methyl glucamine, a white powder.
It is also important to minimize contact between adduct and catalyst when the H₂ pressure is less than about 70.32 bar (1000 psig) to minimize Ni content in the glucamine. The nickel content in the N-methyl glucamine in this reaction is about 100 ppm as compared to the less than 10 ppm in the previous reaction.
The following reactions with H₂ are run for direct comparison of reaction temperature effects.
A 200 ml autoclave reactor is used following typical procedures similar to those set forth above to make adduct and to run the hydrogen reaction at various temperatures.
Adduct for use in making glucamine is prepared by combining about 420 g of about 55% glucose (corn syrup) solution (231 g glucose; 1.28 moles) (the solution is made using 99DE corn syrup from CarGill, the solution having a color less than Gardner 1) and about 119 g of 50% methylamine (59.5 g MMA; 1.92 moles) (from Air Products).
The reaction procedure is as follows:

1. Add about 119 g of the 50% methylamine solution to a N₂ purged reactor, shield with N₂ and cool down to less than about 10°C.
2. Degas and/or purge the 55% corn syrup solution at 10-20°C with N₂ to remove oxygen in the solution.
3. Slowly add the corn syrup solution to the methylamine solution and keep the temperature less than about 20°C.
4. Once all corn syrup solution is added in, agitate for about 1-2 hours.

The adduct is used for the hydrogen reaction right after making, or is stored at low temperature to prevent further degradation.
The glucamine adduct hydrogen reactions are as follows:

1. Add about 134 g adduct (color less than about Gardner 1) and about 5.8 g G49B Ni to a 200 ml autoclave.
2. Purge the reaction mix with about 14.06 bar (200 psi) H₂ twice at about 20-30°C.
3. Pressure with H₂ to about 28.12 bar (400 psi) and raise the temperature to about 50°C.
4. Raise pressure to about 35.16 bar (500 psi), react for about 3 hours. Keep temperature at about 50-55°C. Take Sample 1.
5. Raise temperature to about 85°C for about 30 minutes.
6. Decant and filter out the Ni catalyst. Take Sample 2.

Conditions for constant temperature reactions:

1. Add about 134 g adduct and about 5.8 g G49B Ni to a 200 ml autoclave.
2. Purge with about 14.06 bar (200 psi) H₂ twice at low temperature.
3. Pressure with H₂ to about 28.12 bar (400 psi) and raise temperature to about 50°C.
4. Raise pressure to about 35.16 bar (500 psi), react for about 3.5 hours.
Keep temperature at indicated temperature.
5. Decant and filter out the Ni catalyst. Sample 3 is for about 50-55°C; Sample 4 is for about 75°C; and Sample 5 is for about 85°C. (The reaction time for about 85°C is about 45 minutes.)

All runs give similar purity of N-methyl glucamine (about 94%); the Gardner Colors of the runs are similar right after reaction, but only the two-stage heat treatment gives good color stability; and the 85°C run gives marginal color immediately after reaction.

EXAMPLE IV

The preparation of the tallow (hardened) fatty acid amide of N-methyl maltamine for use in detergent compositions according to this invention is as follows.
Step 1 - Reactants: Maltose monohydrate (Aldrich, lot 01318KW); methylamine (40 wt% in water) (Aldrich, lot 03325TM); Raney nickel, 50% slurry (UAD 52-73D, Aldrich, lot 12921LW).
The reactants are added to glass liner (250 g maltose, 428 g methylamine solution, 100 g catalyst slurry - 50 g Raney Ni) and placed in 3 L rocking autoclave, which is purged with nitrogen [3x35.16 bar (3X500 psig)] and hydrogen [2x35.16 bar (2X500 psig)] and rocked under H₂ at room temperature over a weekend at temperature ranging from 28°C to 50°C. The crude reaction mixture is vacuum filtered 2X through a glass microfiber filter with a silica gel plug. The filtrate is concentrated to a viscous material. The final traces of water are azetroped off by dissolving the material in methanol and then removing the methanol/water on a rotary evaporator. Final drying is done under high vacuum. The crude product is dissolved in refluxing methanol, filtered, cooled to recrystallize, filtered and the filter cake is dried under vacuum at 35°C. This is cut #1. The filtrate is concentrated until a precipitate begins to form and is stored in a refrigerator overnight. The solid is filtered and dried under vacuum. This is cut #2. The filtrate is again concentrated to half its volume and a recrystallization is performed. Very little precipitate forms. A small quantity of ethanol is added and the solution is left in the freezer over a weekend. The solid material is filtered and dried under vacuum. The combined solids comprise N-methyl maltamine which is used in Step 2 of the overall synthesis.
Step 2 - Reactants: N-methyl maltamine (from Step 1); hardened tallow methyl esters; sodium methoxide (25% in methanol); absolute methanol (solvent); mole ratio 1:1 amine:ester; initial catalyst level 10 mole % (w/r maltamine), raised to 20 mole %; solvent level 50% (wt.).
In a sealed bottle, 20.36 g of the tallow methyl ester is heated to its melting point (water bath) and loaded into a 250 ml 3-neck round-bottom flask with mechanical stirring. The flask is heated to ca. 70°C to prevent the ester from solidifying. Separately, 25.0 g of N-methyl maltamine is combined with 45.36 g of methanol, and the resulting slurry is added to the tallow ester with good mixing. 1.51 g of 25% sodium methoxide in methanol is added. After four hours the reaction mixture has not clarified, so an additional 10 mole % of catalyst (to a total of 20 mole %) is added and the reaction is allowed to continue overnight (ca. 68°C) after which time the mixture is clear. The reaction flask is then modified for distillation. The temperature is increased to 110°C. Distillation at atmospheric pressure is continued for 60 minutes. High vacuum distillation is then begun and continued for 14 minutes, at which time the product is very thick. The product is allowed to remain in the reaction flask at 110°C (external temperature) for 60 minutes. The product is scraped from the flask and triturated in ethyl ether over a weekend. Ether is removed on a rotary evaporator and the product is stored in an oven overnight, and ground to a powder. Any remaining N-methyl maltamine is removed from the product using silica gel. A silica gel slurry in 100% methanol is loaded into a funnel and washed several times with 100% methanol. A concentrated sample of the product (20 g in 100 ml of 100% methanol) is loaded onto the silica gel and eluted several times using vacuum and several methanol washes. The collected eluant is evaporated to dryness (rotary evaporator). Any remaining tallow ester is removed by trituration in ethyl acetate overnight, followed by filtration. The filter cake is vacuum dried overnight. The product is the tallowalkyl N-methyl maltamide.
In an alternate mode, Step 1 of the foregoing reaction sequence can be conducted using commercial corn syrup comprising glucose or mixtures of glucose and, typically, 5%, or higher, maltose. The resulting polyhydroxy fatty acid amides and mixtures can be used in any of the detergent compositions herein.
In still another mode, Step 2 of the foregoing reaction sequence can be carried out in 1,2-propylene glycol or NEODOL. At the discretion of the formulator, the propylene glycol or NEODOL need not be removed from the reaction product prior to its use to formulate detergent compositions. Again, according to the desires of the formulator, the methoxide catalyst can be neutralized by citric acid to provide sodium citrate, which can remain in the polyhydroxy fatty acid amide.
Depending on the desires of the formulator, the compositions herein can contain more or less of various suds control agents. Typically, for dishwashing high sudsing is desirable so no suds control agent will be used.

EXAMPLE V

In any of the foregoing examples of detergent compositions, the fatty acid glucamide surfactant can be replaced by an equivalent amount of the maltamide surfactant, or mixtures of glucamide/malt-amide surfactants derived from plant sugar sources. In the compositions the use of ethanolamides appears to help cold temperature stability of the finished formulations. Moreover, the use of sulfobetaine (aka "sultaine") surfactants provides superior sudsing. CaCl₂ can be used (ca. 1%) in the formulations to enhance greasy soil removal from dishes. MgCl₂ enhances sudsing.
Since the present invention provides especially high sudsing compositions, it is preferred that less than about 5%, more preferably less than about 2%, most preferably substantially no C₁₄ or higher fatty acids be present, since these can suppress sudsing. Accordingly, the formulator of high sudsing compositions will desirably avoid the introduction of suds-suppressing amounts of such fatty acids into high sudsing compositions with the polyhydroxy fatty acid amides, and/or avoid the formation of C₁₄ and higher fatty acids on storage of the finished compositions. One simple means is to use C₁₂ ester reactants to prepare the polyhydroxy fatty acid amides herein. Fortunately, the use of amine oxide or sulfobetaine surfactants such as cocoamidopropyl hydroxysultaine and betaines such as cocoamidopropyl betaine can overcome some of the negative sudsing effects caused by the fatty acids.
The formulator wishing to add anionic optical brighteners to liquid detergents containing relatively high concentrations (e.g., 10% and greater) of anionic or polyanionic substituents such as the polycarboxylate builders may find it useful to pre-mix the brightener with water and the polyhydroxy fatty acid amide, and then to add the pre-mix to the final composition.
It will be appreciated by those skilled in the chemical arts that the preparation of the polyhydroxy fatty acid amides herein using the di- and higher saccharides such as maltose will result in the formation of polyhydroxy fatty acid amides wherein linear substituent Z is "capped" by a polyhydroxy ring structure. Such materials are fully contemplated for use herein and do not depart from the spirit and scope of the invention as disclosed and claimed.

Claims

An alkoxy carboxylate detergent composition characterized in that it comprises from 1% to 65% by weight of a surfactant mixture comprising:
(a) from 5% to 95% by weight of one or more alkyl ethoxy carboxylates having the general formula

RO(CH₂CH₂O)_kCH₂COO⁻M⁺

wherein R is a C₈-C₂₂ alkyl group, k is an integer ranging from 0 to 10, and M is a cation; and

(b) from 5% to 95% by weight of one or more polyhydroxy fatty acid amides having the general formula
wherein R¹ is H, a C₁-C₄ hydrocarbyl, 2-hydroxy ethyl, 2-hydroxy propyl, or mixtures thereof, R² is a C₅-C₃₁ hydrocarbyl, and Z is a polyhydroxyhydrocarbyl having a linear hydrocarbyl chain with at least 3 hydroxyl groups directly connected to the chain, or an alkoxylated derivative thereof.
A composition according to Claim 1 wherein the alkyl alkoxy carboxylate component (a) is distributed such that the amount of material where k is 0 is less than 20% and the amount of material where k is greater than 7 is less than 25%, the average k is in the range of from 1 to 4 when the average R is C₁₃ or less, and the average k is in the range of from 2 to 6 when the average R is greater than C₁₃.
A composition according to Claim 1 wherein the detergent composition is a liquid, preferably water or a mixture of water and a C₁-C₄ alcohol, and comprises from 10% to 50% by weight of the surfactant mixture and from 90% to 50% by weight of a liquid carrier.
A composition according to Claim 3 wherein the surfactant mixture comprises from 20% to 80% by weight of the alkyl alkoxy carboxylate component and from 20% to 80% by weight of the polyhydroxy fatty acid amide component.
A composition according to Claim 4 wherein the cation M for the alkyl ethoxy carboxylate (a) is selected from the group consisting of an alkali metal, alkaline earth metal, ammonium, lower alkanol ammonium, and mono-, di-, and tri-ethanolammonium, and mixtures thereof with magnesium and calcium ions.
A composition according to Claim 5 wherein the pH is in the range of from 7.0 to 11.0, and preferably additionally contains from 0.1% to 15% by weight of a buffering agent and also preferably additionally contains from 2% to 5% by weight of a hydrotrope.
A composition according to Claim 6 wherein the liquid detergent contains one or more additional anionic or nonionic surfactants selected from the group consisting of a C₁₂-C₂₇ alkyl ester sulfonates, C₈-C₂₂ primary and secondary alkane sulfonates, C₁₀-C₁₈ alkyl dimethyl amine oxides, alkylpolysaccharides, and mixtures thereof.
A composition according to Claim 7 wherein the surfactant mixture comprises from 40% to 60% by weight of the alkyl ethoxy carboxylate component and from 20% to 60% by weight of the polyhydroxy fatty acid amide component, and wherein the liquid carrier comprises water or a mixture of water and ethanol.
A composition according to Claim 8 wherein the cation M for the alkyl ethoxy carboxylate component (a) is selected from sodium, potassium and ammonium, and mixtures thereof with magnesium and calcium ions, and wherein the polyhydroxy fatty acid amide (b) has the formula
wherein R² is a straight-chain C₁₁-C₁₇ alkyl or alkenyl group, and wherein Z is derived from glucose, maltose or mixtures thereof.
A method for cleaning soiled dishes characterized by contacting said dishes with an effective amount of a detergent composition comprising from 5% to 65% by weight of a surfactant mixture comprising:
(a) from 5% to 95% by weight of one or more alkyl ethoxy carboxylates having the general formula

RO(CH₂CH₂O)_kCH₂COO⁻M⁺

wherein R is a C₈-C₂₂ alkyl group, k is an integer averaging from 1 to 4, and M is a cation; and

(b) from 5% to 95% by weight of one or more polyhydroxy fatty acid amides having the general formula
wherein R¹ is H, a C₁-C₄ hydrocarbyl, 2-hydroxy ethyl, 2-hydroxy propyl, or mixtures thereof, R² is a C₅-C₃₁ hydrocarbyl, and Z is a polyhydroxyhydrocarbyl having a linear hydrocarbyl chain with at least 3 hydroxyl groups directly connected to the chain, preferably C₁₁-C₁₇ N-methyl glucamide, C₁₁-C₁₇ N-methyl maltamide, or mixtures of said glucamide and maltamide, or an alkoxylated derivative thereof; and, optionally,

(c) one or more noncarboxylate anionic surfactants.
A method according to Claim 10 wherein said Z moiety in said polyhydroxy fatty acid amide is derived from mixed monosaccharides, disaccharides and polysaccharides available from plant sources.
A method according to Claim 10 wherein said R² moiety in said polyhydroxy fatty acid amide is C₁₅-C₁₇ alkyl, alkenyl, or mixtures thereof.