WO1994014947A1

WO1994014947A1 - Clear detergent gels

Info

Publication number: WO1994014947A1
Application number: PCT/US1993/012422
Authority: WO
Inventors: Alan Edward Sherry; John Downing Curry
Original assignee: The Procter & Gamble Company
Priority date: 1992-12-28
Filing date: 1993-12-17
Publication date: 1994-07-07
Also published as: MA23073A1; AU5853294A; BR9307795A; CN1090321A; MX9400089A

Abstract

A detergent composition comprising a gel wholly or predominantly in hexagonal liquid crystal phase comprising: (a) from 15 % to 60 % surfactant system comprising: i) from 14.5 % to 59.5 % ethoxylated alkyl sulfate surfactant, and ii) from 0.5 % to 10 % amine oxides or betaines; where the ratio of (i) to (ii) is not more than 40:1; and (b) from 30 % to 80 % water; where the amount of divalent ions in the gel is between 0.2 % and 2.0 %. The detergent gel provides good cleaning and sudsing, and has an aesthetically pleasing clear appearance. Preferred are dishcare gels.

Description

CLEAR DETERGENT GELS

FIELD OF THE INVENTION

This invention relates to detergent compositions, in particular detergents in the form of clear gels in hexagonal liquid crystal phase. A preferred embodiment of the invention is dishcare gels.

Detergents in gel form present many advantages. For example, gel hard surface cleaners adhere well, to the surfaces to be cleaned, are easy to. use, and can provide concentrated cleaning ability. Similarly, laundry detergents in gel form are particularly good at stain removal because they can provide a concentrated amount of surfactants. As another example, dishcare gels are preferred for use in washing dishes in some parts of the world. The gel product form best lends itself to the "direct application" habit in which persons apply a sponge or other cleaning applicator directly onto the dishcare detergent and then onto the dishes; the dishes are then typically washed and rinsed under running water. Additionally, dishcare gels can be stored in inexpensive tubs or similar packages instead of the more complex plastic bottles required for dishwashing liquids.

It is important for detergent gels to provide good cleaning, sudsing and other performance benefits. It is also desirable for detergent gels to have an appearance that is aesthetically pleasing. Moreover, it is desirable for detergent gels to be easy to process, and to have a viscosity that can be adjusted to meet different packaging needs. It would be particularly preferred to have a detergent gel that provides all these beneficial properties.

Therefore, it is an object of the present invention to provide detergent compositions in the form of gels. It is also an object of the present invention to provide detergent gels that have good grease/oil cleaning ability and sudsing, and a good dissolution rate in water.

It is another object of the present invention to provide detergent gels having an appearance that is clear and very aesthetically appealing.

It is still another object of the present invention to provide detergent gels that are easy to process and that form gels quickly upon cooling to facilitate packaging and transportation.

It is a further object of the present invention to provide detergent gels having viscosities which can be easily fine-tuned over a wide range, and are therefore readily adaptable to different consumer preferences and packaging options.

It is a further object of the present invention to provide hexagonal phase detergent gels which can be made without the requirement for additives such as urea.

It is a particular object of the present invention to provide detergent gels in the form of dishcare gels, and to provide dishcare gels that are mild to the hands.

These and other objects of the invention will be described in further detail herein.

SUMMARY OF THE INVENTION

The present invention relates to a detergent composition comprising a gel wholly or predominantly in hexagonal liquid crystal phase, said gel comprising:

(a) from about 15% to about 60% surfactant system by weight of the gel, the surfactant system comprising:

(i) from about 14.5% to about 59.5% ethoxylated alkyl sulfate surfactant by weight of the gel, wherein the alkyl group of the ethoxylated alkyl sulfate surfactant has an average from about 8 to about 20 carbon atoms, and wherein the ethoxylated alkyl sulfate surfactant has an average degree of ethoxylation from about 0.5 to about 15; and (ii) from about 0.5% to about 10%, by weight of the gel, surfactant selected from the group consisting of amine oxides and betaines, and mixtures thereof; wherein the ratio of surfactant (i) to surfactant (ii) is not more than about 40:1; and (b) from about 30% to about 80% water by weight of the gel; wherein the amount of divalent ions in the gel is between about 0.2% and about 2.0% by weight of the gel.

The divalent ions can be introduced into the gel as the cation portion of the ethoxylated alkyl sulfate surfactant, and/or they can be introduced, by adding from 0% to about 8% divalent salts by weight of the gel. The gel can also contain from 0% to about 15% other surfactants by weight of the gel. The detergent gel provides good cleaning, sudsing, and dissolution in water. The detergent gel has a clear, aesthetically pleasing appearance. The gel is easy to process and package, and its viscosity can be easily adjusted. Preferred detergent gels according to the invention are dishcare gels which are mild to the hands.

DETAILED DESCRIPTION OF THE INVENTION

A detergent gel composition according to the present invention comprises from about 15% to about 60% "surfactant system" by weight of the gel. By "surfactant system", as used herein, is meant the total amount of ethoxylated alkyl sulfate, amine oxide, and betaine, these surfactants being discussed in more detail hereinbelow. At least about 15% surfactant system is needed to make a suitably thickened gel. Above about 60% surfactant system, processing becomes more difficult and the mixture may not exist in the hexagonal phase. A detergent gel composition, according to the present invention, preferably comprises from about 20% to about 50% surfactant system, and most preferably from about 25% to about 40%. The surfactant system includes from about 14.5% to about 59.5% ethoxylated alkyl sulfate surfactant by weight of the detergent gel, preferably from about 20% to about 50% ethoxylated alkyl sulfate. Preferably at least about 60% by weight of the surfactant system is the ethoxylated alkyl sulfate surfactant, and more preferably at least about 70% by weight. An ethoxylated alkyl sulfate surfactant, AExS, is one having, on average, "x" degree of ethoxylation. The ethoxylated alkyl sulfate surfactant for use in the present invention has an average degree of ethoxylation from about 0.5 to about 15, and preferably from about 1 to about 6.5. The a kyl group of the ethoxylated alkyl sulfate surfactant can have an average from about 8 to about 20 carbon atoms, preferably from about 8 to about 15 carbon atoms, and most preferably from about 12 to about 15 carbon atoms. The alkyl groups are preferably linear, but they can also be branched.

Blends of different ethoxylated alkyl sulfate surfactants can be used, for example a blend of two surfactants having different degrees of ethoxylation. In general, highly ethoxylated surfactants (e.g., ethoxylation of 3 or more) provide more mildness, while mono- and di-ethoxylated surfactants contribute more to cleaning ability. As a result, it may be desirable to use a blend of AEiS and AE3S or similar blends to provide the optimum combination of cleaning and mildness. Variation in degrees of ethoxylation of the surfactants provides broad formulation flexibility.

The cation group combined with the ethoxylated alkyl sulfate surfactant (an anionic surfactant) can be sodium, potassium, lithium, calcium, magnesium, ethylene diamine, ammonium, aluminum, zinc, or lower alkanol ammonium ions, and other cations which are known in the detergent field to be useful in surfactants. Most preferred are cations selected from the group consisting of magnesium, sodium, and mixtures thereof. The preferred magnesium or sodium ethoxylated alkyl sulfate surfactant can be either introduced as a raw material, or it can be generated in situ through counterion exchange with Mg++ or Na+ salts (this can also be done for the less preferred surfactants). Preferred ethoxylated alkyl sulfate surfactants according to the present invention include those where the alkyl group is derived from coconut or palm base, such as mid-cut coconut (C12-14) or broad-cut coconut (C12-I8)♦ Surfactants of the Cj2-14 type are available commercially from Akzo Chemicals, 516 Duren, West Germany, under the tradenames ELFAN NS 243 S cone, and NS 242 S cone. (Na+ cation, alkyl group having an average chain length of C12-14, average degree of ethoxylation of 3 and 2 respectively), and ELFAN NS 243 S Mg++ concentrate (same as above, but with Mg++ cation); and from Taiwan NJC, No. 45, Chung-Cheng Rd., M1ng-Hsiung Industrial Park, Ming Hsuing, Chia-Yi Hsien, Taiwan, R.O.C. under the tradena e Sinolin SPE-70 (Na AE2S and Na AE3S, where the alkyl group is C12-14).

Synthetic ethoxylated alkyl sulfate surfactants (derived from synthetic alcohols) such as those containing C12-13 or C12-15 alkyl groups are also preferred. Such synthetic surfactants are commercially available from South Pearl Corp., Ponce, Puerto Rico, 00731 and other suppliers. Specific examples of preferred surfactants are Na C12-14AE2S, Na C12-15AE3S, Na C12-13AE1S, and their counterparts containing magnesium cations and/or having other degrees of ethoxylation. Other suitable surfactants include, but are not limited to, ethoxylated alkyl sulfate surfactants where the alkyl group is lauryl (C12) or myristyl (C14).

The ethoxylated alkyl sulfate surfactant used in the detergent gel is preferably a high active surfactant. By "high active" surfactant is meant the surfactant has at least about 60% active surfactancy, preferably at least about 65%. Most preferred are high active surfactants that contain little or no alcohols, glycols, inorganic salts or hydrotopes. Ethoxylated alkyl sulfate surfactant stocks which are not "high active" will necessarily contain additives such as alcohols and glycols, or hydrotropes such as toluene, xylene and cumene sulfonates. The ethoxylated alkyl sulfate surfactant stocks of this invention should contain little or no short chain alcohols and glycols (C6 or lower), preferably less than about 10%^*by weight, most preferably less than about 5% by weight. Additionally, they should contain little or no hydrotropes, preferably less than about 8% by weight, most preferably less than about 4% by weight. Without limiting the scope of this invention, it has been found that stable hexagonal phase gels can be made in the presence of small quantities of alcohols, glycols and/or hydrotropes, but these gels usually require higher surfactant concentrations.

In addition to the ethoxylated alkyl sulfate surfactant, the surfactant system of the detergent gel also includes from about 0.5% to about 10%, by weight of the gel, surfactant selected from the group consisting of amine oxides and betaines, and mixtures thereof.

Amine oxide semi-polar nonionic surfactants comprise compounds and mixtures of compounds having the formula:

R2

I

Rl(C2H4θ)_nN — 0

I R3

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

R2

I

Rl — N —> 0

I

R3 wherein Ri is a Cχo-18 ^a1kyl and R2 and R3 are methyl. The above amine oxides are more fully described in U.S. Patent 4,316,824 to Pancheri, which is incorporated herein by reference. The Procter & Gamble Company, Cincinnati, Ohio, also manufactures suitable amine oxides such as Cιo-16 (predominantly C12) alkyl dimethyl amine oxides. The C12, C14, Ci6, 14.16, and Ci6_ιs alkyl dimethyl amine oxides are available commercially from Stepan Chemical Company under the tradename Ammonyx. It has been found that longer chain amine oxides provide particularly good cleaning benefits, as determined by interfacial tension measurements. The benefits of the longer chain length amine oxides are illustrated in Examples 2 and 3.

Betaines are surfactants having the general formula:

(+) (-)

wherein R is a hydrophobic group selected from the group consisting of alkyl groups containing from about 10 to about 22 carbon atoms, preferably from about 12 to about 18 carbon atoms; alkyl aryl and aryl alkyl groups containing a similar number of carbon atoms with a benzene ring being treated as equivalent to about 2 carbon atoms, and similar structures interrupted by amido or ether linkages; each Rl is an alkyl group- containing from 1 to about 3 carbon atoms; and R2 is an alkylene group containing from 1 to about 6 carbon atoms. Examples of preferred betaines are cetyl dimethyl betaine, dodecyl dimethyl betaine, coco amido propyl betaine, dodecyl amidopropyldimethyl betaine, and dodecyldimethylammonium hexanoate. Other suitable amidoalkyl betaines are disclosed in U. S. Pat. Nos. 3,950,417; 4,137,191; 4,375,421; and 4,555,360; and British Patent GB No. 2,103,236, all of which are incorporated herein by reference. Betaines are preferably used in conjunction with amine oxides, as formulations which contain only betaine (and no amine oxide) do not provide optimal cleaning.

The ratio of ethoxylated alkyl sulfate:amine oxide and/or betaine should be not more than about 40:1, and preferably not more than about 20:1. Addition of amine oxide and/or betaine tends to reduce the viscosity of the gels, but these surfactants are important for their contribution to cleaning performance and sudsing, and are thus an indispensable component of this invention.

A gel according to the present invention will contain from about 0.2% to about 2.0% divalent ions by weight of the gel. Divalent ions can be introduced by use of magnesium and/or calcium neutralized ethoxylated alkyl sulfate surfactants and/or other surfactants. Divalent ions can also be introduced in the form of divalent salts. Examples of divalent salts include magnesium sulfate, magnesium formate, magnesium chloride, calcium chloride, and others. Divalent salts may also be introduced as impurities in the surfactants used. For example, magnesium sulfate impurity is usually present in a magnesium ethoxylated alkyl sulfate surfactant as a result of the synthesis process used. In total, the gels of the present invention will contain from 0% to about 8% divalent salts.

When excellent performance hexagonal phase gels of high viscosity are desired (2.0 - 4.5 million centipoise), it is preferable to use magnesium neutralized stock surfactants, most preferably high active surfactants. High performance hexagonal phase gels of low viscosity (0.5 - 2.0 million centipoise) can be obtained from magnesium neutralized surfactants, or surfactants neutralized with onovalent cations, provided that divalent salts are added into the formulation. Most preferred formulations contain divalent ions in the form of magnesium ions. These formulations form aesthetically attractive, clear, transparent gels and have the most desirable performance characteristics. Formulations that contain the divalent ions in the form of calcium ions tend to be more opaque and do not have as good performance properties.

Along with the ethoxylated alkyl sulfate and amine oxide and/or betaine surfactants, the detergent gel can also optionally include from 0% to about 15% other surfactants by weight of the gel. The other surfactants can be anionic, cationic, nonionic, zwitterionic, ampholytic or amphoteric surfactants known to persons skilled in the art. Preferably not more than about 5% by weight cationic surfactant is used. Preferred surfactants are nonionic. Nonionic surfactants useful in the detergent gel of this invention include the fatty acyl ethanolamides, ethoxylated fatty alcohols, alkyl phenols, polypropylene oxides, polyethylene oxides, copolymers of polypropylene oxide and polyethylene oxide, sorbitan esters, and the like.

A detergent gel composition according to the invention also contains from about 30% to about 80% water by weight of the gel, preferably from about 40% to about 70%, and most preferably from about 45% to about 65%.

The viscosity of a detergent gel of the present invention can be easily tuned over a wide range of viscosities by varying the total amount of electrolytes in the gel. The electrolytes are inorganic or organic salts ( onovalent, divalent or trlvalent) which are either intentionally added for their performance benefits in the gel (e.g., the added divalent salts discussed above), or which are incorporated into the gel as part of a raw material (e.g., as an impurity present in a raw material as a result of a manufacturing process). The electrolytes are preferably introduced as the divalent salts.

The detergent compositions of this invention can contain thickening or suspending agents or fillers, although these materials usually opacify the gel. If used, these materials should be limited to no more than about 2% by weight of the gel composition.

The detergent gel composition of the Invention can contain, if desired, other additives known to persons skilled in the art for use in detergents, for example, bleaching agents, perfumes, builders, amino acids, dyes, ant1tarnishing agents, antimicrobial agents, abrasives, suds enhancers, coloring agents, and the like. The amounts of these additives should be limited to avoid interfering with the clarity and viscosity of the gel.

To provide optimum cleaning properties, product viscosity, and overall performance, the pH of a 6% product concentration of the present detergent compositions is preferably maintained at a pH between about 7.0 and about 9.0, more preferably between about 7.0 and about 8.0. The detergent compositions of the present invention are in the form of gels which have a viscosity between about 500,000 centipoise and about 4,500,000 centipoise. As discussed hereinabove, the viscosity of the gels can be readily varied within this viscosity range depending on the properties desired in the final product. Viscosity measurements of the gels of this invention are taken by means of an Exact Viscometer HAAKE RV20 ROTOVISCO using Cone P 1; r with M-30.2. The viscosity is measured on a 0.5 gram sample of the gel sandwiched between the Cone and the instrument's plate, using a shear rate gradient of 0 to 3 seconds"!, at a temperature of 23'C (73.4^*F). The recorded viscosity corresponds to the highest viscosity reading obtained on the instrument when a sweep time of 2 minutes is used.

A detergent gel according to this invention is wholly or predominantly in hexagonal liquid crystal phase. By "predominantly" is meant greater than about 50%. The liquid crystal phase of the detergent gel can be determined by polarizing light microscope studies, use of X-ray diffraction or other various spectroscopic techniques known to persons skilled in the art. The hexagonal liquid crystal phase is intermediate in rigidity between the lamellar and cubic liquid crystal phases. The hexagonal liquid crystal phase is further described at column 3, lines 12-31, of U.S. Patent 4,615,819 to Leng et al., issued October 7, 1986, which is incorporated by reference herein.

The detergent compositions of this invention can be dishwashing detergents for use with the "direct application" habit discussed above, or for use with batch dishwashing typical of liquid detergents; general purpose industrial and household cleaners for use in cleaning hard surfaces such as metal, glass, ceramic, tile and linoleum; concentrated laundry detergents; hand cleaners; shampoos; or other detergent compositions known in the detergent field. Laundry detergents according to the invention will contain surfactant, builder, and typically components such as brighteners, bleach, enzymes, chelating agents, and suds suppressors. General purpose hard surface cleaners will contain surfactants, builder, and someti es abrasive and solvent. Most preferred detergents according to this invention are dishcare gels suitable for use with the direct application habit, in removing food soils from housewares including dishes, pots and pans, glasses, utensils, etc.

The detergent gel compositions of the invention can be prepared in any suitable manner, for instance by simply mixing together the components. The gels are easily processable as fluid liquids at temperatures of 140'F (60'C) to 190'F (88'C), preferably about 180'F (82^*C) to 190^*F (88'C). The order of mixing of the components is not critical. A preferred order of addition involves dissolution of divalent salts, amine oxides and betaines first, followed by addition of other nonionic surfactants. The ethoxylated alkyl sulfate surfactant is preferably added to the mixture last. Upon cooling, the compositions become viscous and set up as gels more quickly than similar gels made with urea or other additives. This is advantageous because the gels can be packaged and transported without concern that they will flow and lose their desired shape.

An important advantage of the present detergent gel compositions is that they are very mild to the skin, for example mild to the hands during dishwashing. This benefit is possible because the detergent gels provide excellent cleaning and sudsing without the use of harsh surfactants. U.S. Patent 4,555,360 to Bissett et al., issued November 26, 1985, presents dishwashing panelist and hand soak test data (Examples I and II) showing that liquid detergents containing ethoxylated alkyl sulfate, betaine and amine oxide are very mild to the hands.

As mentioned above, the detergent gel compositions provide good cleaning of grease/oil and other soils, good sudsing, and good overall performance. A low interfacial tension or "IFT" (disclosed in Examples 1 and 3 hereinbelow) is a measure of good grease/oil cleaning ability. Moreover, the detergent gels provide a good dissolution rate in water. The detergent gels of the invention have an excellent appearance and a smooth, homogeneous consistency. The very aesthetically appealing gels can be colorless or colored, and transparent or translucent; the formulations offer complete flexibility with regard to choice of dye and desired opacity. Particularly preferred gels have an excellent clear, water-white appearance.

As previously discussed, the viscosity of the detergent gels can be easily fine-tuned over a wide viscosity range. This ease of viscosity adjustment is possible because the relationship between percent electrolyte and viscosity of the detergent gels of the invention is a gently sloping curve (illustrated in Example 2, hereinbelow). As a result, the gel viscosity can be readily adjusted to accommodate a variety of packaging needs and consumer preferences.

The detergent gels- of the invention have good viscosity and performance without requiring the use of additives such as urea or hydrotropes which are commonly found in other detergent gels. The gels have less than 1% urea. Consequently, it is unnecessary to add a large amount of perfume to mask ammonia odor which can form in urea-containing gels at high pH. The gels of the invention have only a mild base odor which is easily overcome by addition of small amounts of perfume.

The following nonlimiting examples are performed using water at a 6-12 grains per gallon hardness. All percentages herein are by weight unless otherwise defined.

EXAMPLE 1

A dishcare gel according to the present invention is made as fol1ows:

Active Final Product Formula: Percent

Magnesium triethoxylated 28.50% alkyl sulfate*

Amine oxide** 4.75%

Water 66.75%

^rM9(Cl2-14AE3S)2 (70% active, manufactured by the Akzo Chemical Company, Duren, Germany)

** Cχo-16 Dimethyl amine oxide (32% active, manufactured by The Procter & Gamble Company, Cincinnati, OH, U.S.A.)

Process:

14.84 grams of amine oxide are stirred into, and dissolved in 44.44 grams of water at 70'-80^*F (21.T-26.7'C) using a LABMASTER 1500 MSV 1500 U mixer. The resulting solution is then heated to 160*F (71.l'C) and 40.71 grams of Mg(Ci2-i4AE3S)2 are added. The mixture is stirred continually at lδO'-UO'F (71.r-76.7^*C) until a homogeneous solution is obtained. Upon cooling, .a clear stable gel having an excellent appearance is obtained. The gel is predominantly in hexagonal liquid crystal phase as determined by x-ray diffraction. The amount of divalent ions in the gel is about 0.9% by weight of the gel. Gel viscosity at 23^*C (73.4'F) is 3.1 million centipoise. The interfacial tension ("IFT") of the product is 0.7 dyne/cm, indicating good cleaning (IFT is measured at 6% product concentration, at 23^*C [73.4^*F], not more than 10 grains per gallon water hardness, using a "soil" composed of 99.8% canola oil and 0.2% oleic acid, and measured by a Model 500 Spinning Drop Interfacial Tensiometer manufactured by the University of Texas, U.S.A. A lower interfacial tension measurement suggests improved cleaning performance.) The pH of the product at a 6% concentration in water is 7.8. The product provides good sudsing and has excellent stability.

EXAMPLE 2

The following Examples 2A, 2B and 2C illustrate how the viscosity of a final product can be fine-tuned by controlling the level of electrolyte present in the formulation.

Example 2A:

A dishcare gel according to the present invention is made as fol1ows:

Active Final Product Formul : Percent

Sodium triethoxylated 28.50% alkyl sulfate*

Amine oxide** 4.75%

MgS04 2.00%

Water 64.75%

*Na C12-15AE3S (69.3% active, manufactured by South Pearl Corporation, Puerto Rico, U.S.A.) **Same as in Example 1

Process:

To 42.0 grams of water, 2.02 grams of MgSθ4 (99% active) and 14.84 grams of amine oxide are added at 70'-80^*F (21.r-26.7^*C) with stirring. Once a homogeneous solution is obtained, the solution is heated to 165-170'F (73.9'-76.7^*C) and 41.1 grams of Na C12-15AE3S are added. The mixture is then continually stirred until it again becomes homogeneous. The final product is a liquid which forms a soft gel upon cooling to yield a clear, water-white predominantly hexagonal phase gel. Product viscosity at 23^*C (73.4'C) is 2.0 million centipoise. Exa pl e 2B :

A dishcare gel is made as described in Example 2A, except that the gel is formulated to contain 2.50% MgSθ4 (instead of 2.00%) and

64.25% water. The product is a predominantly hexagonal phase gel having a viscosity of 1.5 million centipoise at 23^*C (73.4*F).

Example 2C:

A dishcare gel is made as described in Example 2A, except that the gel is formulated to contain 3.00% MgS04 (instead of 2.00%) and 63.75% water. The product is a predominantly hexagonal phase gel having a viscosity of 0.8 million centipoise at 23^*C (73.4'F).

Discussion:

It is seen from Examples 2A, 2B and 2C that the viscosity of the gels can be readily adjusted by varying the amount of electrolytes.

% Electrolyte

Example as MQSOA Viscosity (cPl

2A 2.00 2.0 million

2B 2.50 1.5 million 2C 3.00 0.8 million

EXAMPLE 3

Dishcare gels with improved ability to reduce oil/water interfacial tension are made using formulas similar to those described in Examples 2A and 2C, except that a longer chain length amine oxide is employed.

Example 3A;

Active Final Product Formula: Percent

Sodium triethoxylated 28.50% alkyl sulfate*

C14-16 amine oxide** 4.75%

MgS04 2.00%

Water 64.75%

* Same as in Example 2 ** Myristyl-cetyl dimethyl amine oxide

(29.3% active, manufactured by Stepan, Northfield, Illinois, U.S.A., and sold under the tradename A monyx MCO)

Process:

To 40.64 grams of water, 2.02 grams of MgSθ4 (99% active) and 16.21 grams of amine oxide are added at about 70*-80^*F (21.1^*-26.7*C) with stirring. Once a homogeneous solution is obtained, the solution is heated to 175^*-180'F (79.4'-82.2'C) and 41.1 grams of NaCi2-isAE3S are added. The mixture is then stirred for about 1 hour. The mixture forms into a clear gel immediately upon cooling. Polarized light microcopy studies indicate the gel is predominantly hexagonal phase. The viscosity of the gel is about 2.5 million centipoise at 23*C (73.4'F). The interfacial tension (conditions identical to those described in Example 1) of the product is 0.65 dyne/cm at pH 8.0. For comparison purposes, the interfacial tension of the product made in Example 2A which uses Cιo-16 (predominantly C12) amine oxide under similar experimental conditions is 1.0 dyne/cm. The use of the C14-I6 amine oxide brings about a significant improvement in performance.

Example 3B:

A dishcare gel is made as described in Example 3A, except that the gel is formulated to contain 3.00% MgS04 (instead of 2.00%) and 63.75% water (instead of 64.75%). The product is a predominantly hexagonal phase gel with a viscosity of 0.7 million centipoise at 23'C (73.4'F), and an IFT of 0.55 dyne/cm. The comparable gel using C10-I6 amine oxide (predominantly C12) in Example 2C has a viscosity of 0.8 million centipoise and an IFT of 0.75 dyne/cm.

EXAMPLE 4

A dishcare gel according to the present invention is made as follows:

Active Final Product Formula: Percent

Sodium triethoxylated 28.50% alkyl sulfate*

Betaine** 4.75%

MgS04 3.00%

Water 63.75%

^♦Same as in Example 2

**Coco amido propyl betaine (30% active, manufactured by the Sherex Corporation, U.S.A.)

3.00 grams of MgS04 are stirred in and dissolved in water at 70^*-80'F (21.1'-26.7'C), 15.8 grams of betaine are added, and the mixture is then heated to 165'-170'F (73.9'-76.7'C). Once a homogeneous solution is obtained, 41.1 grams of aCi2-isAE3S are added. The mixture is then stirred at constant heat until a homogeneous solution is obtained. Upon cooling, the final product is a soft gel with a viscosity of 0.8 million centipoise at 23'C (73.4'F). The amount of divalent ions in the gel is about 0.6% by weight of the gel. The gel has an excellent clear, water-white appearance, and the gel is predominantly in hexagonal liquid crystal phase. EXAMPLE 5

A dishcare gel according to the present invention is made as follows:

Active Final Product Formula: Percent

Sodium diethoxylated 28.50% alkyl sulfate*

Amine oxide** 4.75%

Magnesium formate*** 1.75%

Q Water 65.00%

*NaCi2-l4AE S obtained as a 70% active paste from Akzo Chemical, Duren, Germany under the tradena e ELFAN NS 242 S cone. The surfactant stock contains no alcohol or hydrotropes.

5 **Same as in Example 1.

***The magnesium formate (95% active) is purchased from Pfaltz and Bauer Inc., Waterbury, Connecticut, U.S.A. It is further purified by dissolving the purchased material in hot water and filtering out insoluble particles. The water is removed from the soluble fraction by evaporation to dryness. The resulting white powder is then stored in an oven prior to use.

Process:

1.84 grams of magnesium formate and 14.75 grams of amine oxide are dissolved in 44.53 grams of water at 70'-80'F (21.1'-26.7'C) . The mixture is then heated to 180'F (82.2'C), and 40.71 grams of aCi2-l4AE2S are added with stirring. The final product is a viscous liquid which forms into a clear stable gel upon cooling. The gel is predominantly hexagonal phase and it has an excellent appearance. Product viscosity at 23'C (73.4'F) is 1.0 million centipoise. The divalent ion concentration is 0.37% by weight of the gel.

EXAMPLE 6

The following example illustrates the formation of a hexagonal phase dishcare gel with an AE1S/AE6.5S surfactant paste that contains ethanol :

Active

Final Product Formula: Percent

NH4AE1S* 19.75%

NH4AE6.5S* 15.25%

Ethanol* 8.00%

Amine oxide** 3.20%

MgS0₄ 2.00%

Water 51.80%

^♦Derived from a pre-made paste which contains 38.4% NH4 Cl2-13AEιS, 28.6% NH4 C12.13AE6.5S and 11.75% ethanol.

**Same as in Example 1.

Process:

2.00 grams of MgS04 and 9.94 grams of amine oxide are added with stirring to 38.59 grams of water at 57'-70'F (13.9'-21.1'C). The mixture is then heated to 178'F (81.1'C), and 51.47 grams of surfactant paste are added. The mixture is heated until all the paste is dissolved and a homogeneous solution obtained. Upon cooling, an attractive transparent gel with a viscosity of 1.3 million centipoise at 23'C (73.4'F) is obtained. Polarized light microscopy indicates a predominantly hexagonal phase gel. The gel contains 0.4% by weight divalent ions.

EXAMPLE 7

The following dishcare gel example incorporates calcium ions into the formul ation:

*Same as in Example 1

Process:

To 40.66 grams of water, 0.86 grams of CaCl2 (96.5% active) and 8.11 grams of amine oxide are added at 70*-80' (21.1'-26.7'C) with stirring. Once a homogeneous solution is obtained, the mixture is heated to about 175'F (79.4'C), and 40.71 grams of Mg (Ci2-14AE3S)2 paste are added. Stirring is continued at about 175'F (79.4'C) until all of the Mg (C 2-14AE3S)2 paste is dissolved and mixed. The final product is a liquid which cools to form a clear gel with a viscosity of 0.7 million centipoise at 23'C (73.4'F). The IFT of this product (conditions as in Example 1) is 1.15 dynes/cm. The final product contains about 1.2% divalent ions by weight.

Claims

1. A detergent composition comprising a gel wholly or predominantly in hexagonal liquid crystal phase, said gel comprising: (a) from 15% to 60% surfactant system by weight of the gel, the surfactant system comprising:

(i) from 14.5% to 59.5% ethoxylated alkyl sulfate surfactant by weight of the gel, wherein the alkyl group of the ethoxylated alkyl sulfate surfactant has an average from 8 to 20 carbon atoms, and wherein the ethoxylated alkyl sulfate surfactant has an average degree of ethoxylation from 0.5 to 15; and (ii) from 0.5% to 10%, by weight of the gel, surfactant selected from the group consisting of amine oxides and betaines, and mixtures thereof; wherein the ratio of surfactant (i) to surfactant (ii) is not more than 40: 1 ; and

(b) from 30% to 80% water by weight of the gel; wherein the amount of divalent ions in the gel is between 0.2% and 2.0% by weight of the gel.

2. A detergent composition according to Claim 1 wherein the cation group combined with the ethoxylated alkyl sulfate surfactant is selected from the group consisting of magnesium, calcium, and sodium cations, and mixtures thereof.

3. A detergent composition according to Claim 1 wherein the divalent ions are present as magnesium ions.

4. A detergent composition according to Claim 1 wherein the amine oxides are selected from the group consisting of C alkyl dimethyl amine oxides and

C alkoxy ethyl dihydroxy ethyl amine oxides, and mixtures thereof.

5. A detergent composition according to Claim 1 wherein the betaines are selected from the group consisting of alkyl betaines, amido betaines, and mixtures thereof.

6. A detergent composition according to Claim 1 wherein the ratio of surfactant (i) to surfactant (ii) is not more than 20: 1.

7. A detergent composition according to Claim 1 which contains from 0% to 8% divalent salts by weight of the gel.

8. A detergent composition according to Claim 1 wherein the pH of the composition is between 7.0 and 9.0.

9. A detergent composition according to Claim 1 which is a dishcare gel.