Although the use of anionic surfactants in these compositions permits the attainment of desirable properties, including good foamability, the degree of foaming and its stability is oftentimes still insufficient.

Foam stability relates to the ability of the foam, once formed, to remain intact for extended periods of time, thus enhancing the cleaning performance of the surfactant compositions.

It is sometimes advantageous to use mixtures of surfactants in cleaning compositions wherein the surfactants can serve different functions, e. g., one serving to improve foamability and another serving to adjust viscosity. However, known surfactant mixtures typically provide a compromise when compared to the specific characteristics of the individual surfactants if used by themselves. For example, a mixture of more costly surfactants such as amine oxides, betaines and alkanolamides which provide good foamability by themselves, with less expensive surfactants which provide poorer foamability, will result in the formulation of a surfactant composition having an intermediate degree of foamability and poor foam stability.

While mixtures of alkyl glycosides and anionic surfactants oftentimes result in the formation of a surfactant composition which produces adequate amounts of stable foam, even higher levels of more stable foam are desirable for many applications.

BRIEF SUMMARY OF THE INVENTION : The present invention is directed to a cleaning composition containing a mixture of : (a) an alpha-olefin sulfonate ; (b) a sugar surfactant selected from the group consisting of an alkyl polyglycoside, a polyhydroxy fatty acid amide and mixtures thereof ; and (c) a foam stabilizer, wherein the alpha-olefin sulfonate and sugar surfactant are present in the composition in a ratio by weight of from about 1 : 2 to about 2 : 1.

The present invention is also directed to a process for making a cleaning composition involving : (a) providing an alpha-olefin sulfonate ; (b) providing a sugar surfactant selected from the group consisting of an alkyl polyglycoside, a polyhydroxy fatty acid amide and mixtures thereof ; (c) providing a foam stabilizer ; and (d) combining (a) - (c) to form a cleaning composition, and wherein (a) and (b) are combined in a ratio by weight of from about 1 : 2 to about 2 : 1.

DETAILED DESCRIPTION OF THE INVENTION : Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as being modified in all instances by the term "about".

It has surprisingly been discovered that by combining an alpha-olefin sulfonate with an alkyl polyglycoside, a synergy is realized in terms of foam stability which results in enhanced cleaning effectiveness.

The alpha-olefin sulfonates which may be employed by the present invention include those having a carbon chain length of from about 6 to about 30. Particularly preferred alpha-olefin sulfonates are those having a C14 to C16 carbon chain length.

Suitable sugar surfactants which may be employed by the present invention include, but are not necessarily limited to, polyhydroxy fatty acid amides, alkyl polyglycosides, and mixtures thereof. The polyhydroxy fatty acid amides which can be used in the compositions and processes according to the invention correspond to formula I : 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 C alkyl (i.e., methyl); and R2 is a C -c3l hydrocarbyl moiety, preferably straight chain C7-C, g alkyl or alkenyl, more preferably straight chain Cg-Cl7 alkyl or alkenyl, most preferably straight chain C11-C19 alkyl or alkenyl, or mixtures thereof ; and Y is a polyhydroxyhydrocarbyl moiety having a linear hydrocarbyl chain with at least 3 hydroxyls directly connected to the chain, or an alkoxylated derivative (preferably ethoxylated or propoxylated) thereof. Y preferably will be derived from a reducing sugar in a reductive amination reaction ; more preferably Y is a glycityl moiety. 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 Y. It should be understood that it is by no means intended to exclude other suitable raw materials. Y preferably will be selected from the group consisting of -CHZ- (CHOH) n-CHzOH, -CH(CH20H)-(CHOH) n- 1-CH20H, -CH2-(CHOH) 2 ( CHOR')(CHOH)-CH20H, where n is an integer from 3 to 5, inclusive, and R'is H or a cyclic mono- or poly- saccharide, and alkoxylated derivatives thereof. Most preferred are glycityls wherein n is 4, particularly -CH2-(CHOH)4-CH20H. Compounds of the formula I are also known as glucamides. Therefore, when, for example, Ri is methyl, R2 dodecyl; and Y is -CH2-(CHOH)4-CH20H, the compound in question is referred to as dodecyl N-methylglucamide.

Methods for making polyhydroxy fatty acid amides are known in the art. In general, polyhydroxy fatty acid amides can be made by reductively aminating a reducing sugar reacting with an alkyl amine to form a corresponding N-alkyl polyhydroxyamine and then reacting the N-alkyl polyhydroxyamine with a fatty aliphatic ester or triglyceride to form the N-alkyl, polyhydroxy fatty acid amide. Processes for making polyhydroxy fatty acid amides are disclosed in U. S. patent numbers 1, 985, 424 ; 2, 965, 576 ; 5, 194, 639 ; and 5, 334, 764, the entire contents of each of which is incorporated herein by reference.

The alkyl polyglycosides which may be employed by the present invention correspond to formula II : R30 (Z) a (II) wherein R3 is a monovalent organic radical having from about 12 to about 16 carbon atoms ; Z is a saccharide residue having 5 or 6 carbon atoms ; and a is a number having a value from about 1. 4 to about 1. 6. Such alkyl polyglucosides which are made by reacting a mixture of fatty alcohols having 12 to 16 carbon atoms and glucose and are available commercially, for example, from Henkel Corporation as GLUCOPONG) 600 and GLUCOPONX 625 SURFACTANT, or APG 600 and APGd9 625 SURFACTANT or PLANTARENO 1200 and 1300 SURFACTANT.

These alkyl polyglycosides have an average degree of polymerization, which is typically defined as the average number of repeat units, or in this case glucose units, per polymer chain, in the range of about 1. 4 to about 1. 6. The pH of the alkyl polyglycoside is typically in the range of about 6 to about 12. The percent actives of the alkyl polyglycosides employed in the present invention is in the range of about 5 to about 80%, and preferably about 40%.

Examples of suitable foam stabilizers include, but are not limited to, amides such as monoethanolamides and diethanolamides, betaines such as coco betaine and cocoamidopropyl betaine, amine oxides such as cocoamidopropyl amine oxide and cocodimethyl amine oxide, and amphoacetates. A particularly preferred foam stabilizer for use in the present invention is a cocodimethyl amine oxide. The foam stabilizer will typically be used at from about 0. 5 to about 10. 0% actives, and preferably at about 1. 5% actives.

According to one embodiment of the present invention, there is provided a cleaning composition containing : (a) from about 5 to about 50% by weight, preferably from about 5 to about 30% by weight, and most preferably from about 10 to about 25% by weight, of an alpha-olefin sulfonate, preferably a Cl4 l6 alpha-olefin sulfonate ; (b) from about 5 to about 50% by weight, preferably from about 5 to about 30% by weight, and most preferably from about 10 to about 25% by weight, of a sugar surfactant, preferably an alkyl polyglycoside ; and (c) from about 0. 5 to about 10. 0% by weight, preferably from about 1. 0 to about 7. 0% by weight, and most preferably about 1. 5% by weight of a foam stabilizer, preferably cocodimethyl amine oxide. The specific amounts of alpha-olefin sulfonate and sugar surfactant to be employed will depend on the particular cleaning composition being formulated, i. e., a dishwashing liquid, a hair shampoo, a personal cleansing bar, etc. , and can be determined by those skilled in the relevant art.

However, it is imperative that these two compounds be employed at a ratio by weight of from about 2 : 1 to about 1 : 2, and preferably about 1 : 1, in order to realize a synergy in foam stability and enhanced cleaning efficacy.

The cleaning composition of the present invention may contain additional components which are conventionally used such as viscosity modifiers, pH adjusters, colorants, pearlizing agents, clarifying agents, fragrances, preservatives, antioxidants, chelating agents, skin and hair conditioners, botanical extracts, and antibacterial agents.

The present invention also provides a process for formulating a cleaning composition having enhanced foam stability and cleaning efficacy involving combining the above-identified components in the disclosed ratios by weight and weight percentages.

The present invention will be better understood from the examples which follow, all of which are intended to be illustrative only and not meant to unduly limit the scope of the invention. Unless otherwise indicated, percentages are on a weight-by-weight basis.

EXAMPLES Formulations were tested containing 20% active primary surfactant and 1. 5% active lauryl monoethanol amide as a foam stabilizer, totaling 21. 5% active surfactant compositions. The formulations were tested using a Terg Test(1) and a Modified Shell Test The results are found in Table 1, below. Component Modified Shell Terg Test | AOS 28.5 9.8 LAS 20. 5 5. 9 GLUCOPON 625 30. 1 7. 5 AES-2EO 28.0 8.5 AOS/AES (1:1)32.59.4 AOS/LAS (1:1)24.08.4 AOS/GLUCOPON 625 (1 : 1) 38. 5 10. 0 (1) The modified shell test is used to evaluate the performance of a liquid hand dishwashing detergent. The materials employed in running this test include : a surfactant, Crisco shortening, olive oil, potato powder, milk, an aluminum mold, a stop watch, a thermometer, a tergotometer, waxed paper, a rubber spatula and dry ice.

Soil pellets were prepared comprising : 15. 0% potato powder, 24. 8% deionized water, 30. 0% milk, 15. 0% olive oil, 15. 0% melted Crisco, and 0. 2% formaldehyde. These ingredients were stirred with a high speed mixer until smooth and creamy, after which pellets were formed.

A 4% aqueous solution of cleaning composition was prepared using 3 mls of the test solution in a tergotometer bucket containing 397 mls of water. The temperature of the tergotometer bath was adjusted to 110°F. Each bucket was filled with 367 mls of DI water and 30 mls of 2000 ppm concentrated hard water to give a calculated water hardness of 150 ppm. The temperature in the bucket was 108°F when the test was begun.

The test detergent solution was agitated and soil pellets were added every 30 seconds until a no foam end point was reached.

(2) The terg test is also used to evaluate the performance of a liquid hand dishwashing detergent. The materials used in this test include : a surfactant, a whole egg powder, Crisco Shortening, terry cloth swatches, a stop watch, a mixer with a stainless steel bowl, 1-3 ml SML digital adjust micro/pettor, a balance, a thermometer and a tergotometer.

A 400g soil preparation was formed by combining 150. Og of 37. 5% Crisco Shortening, 50. Og of 12. 5% egg powder and 200. Og of 50% 150 ppm hard water. The soil preparation was applied onto the swatches which, when dried, weighed 0. 97 grams.

A 4% aqueous solution of detergent was prepared, wherein 15 mls of the solution was added to 385 ml of water into the tergotometer bucket. The tergotometer was then heated to 110°F. Each bucket was filled with 355 mls of distilled water and 30 mls of 2000 ppm concentrated hard water. The agitation speed was adjusted to 75 rpm using a hand crank. The detergent was added and agitated for 1 min and 45 sec. Into the bucket there was then added one swatch, at which time agitation was again begun for 45 sec.

Soil addition and agitation was repeated until a no foam end point was reached.

As is clearly seen from the results, by employing an alpha-olefin sulfonate and an alkyl polyglycoside in a ratio by weight of 1 : 1 (10% active : 10% active), significantly enhanced foam stability and cleaning efficacy properties are obtained. The advantages associated with this discovery include : (1) the ability to manufacture an inexpensive, yet highly effective cleaning composition ; (2) the ability to lower the chemical content of a cleaning composition by employing less total actives of the surfactant components, while maintaining exceptional cleaning efficacy, thereby imparting less of an environmental impact ; and (3) the ability to formulate a cleaning composition which is very mild to the skin since both alpha-olefins and sugar surfactants are known to possess a low skin-irritation profile.