Foaming dishwashing liquid compositions

Technical field

This invention relates to surfactant combinations which provide controllable aqueous foams. Such compositions can be used in any situation where foams are desirable, including the laundry, personal cleaning products, dishwashing, fire fighting, oil well drilling, ore beneficiation, solution mining, washing hair, preparation of foamed solid structures, etc.

Description of the prior art

Alkylpolyglycosides which are surfactants have been disclosed in U.S. Patents 3,598,865; 3,721,633; and 3,772,269. These patents also disclose processes for making alkylpolyglycoside surfactants and built liquid detergent compositions containing these surfactants. U.S. Patent 3,219,656 discloses alkylmonoglucosides and suggests their utility as foam stabilizers for other surfactants. Various polyglycoside surfactant structures and processes for making them are disclosed in U.S. Patents 2,974,134; 3,640,998; 3,839,318; 3,314,936; 3,346,558; 4,011,389; 4,223,129.

Foaming compositions containing an alkylpolysaccharide surfactant, an anionic cosurfactant and possibly an auxiliary foam booster, are described in copending published EP-A-0 070 076 and EP-A-0070074.

Light duty detergent compositions containing an alkylpolysaccharide, alkylbenzene sulfonate and alkylpolyethoxylate sulfate cosurfactants are described in published EP-A-0 070 077.

All percentages, parts and ratios used herein are by weight unless otherwise specified.

Summary of the invention

This invention relates to the discovery of certain combinations of surfactants which provide unusual foams. Specifically this invention relates to foaming compositions comprising:

• (1) an alkylpolysaccharide surfactant having the formula RO(R'O)_tZ_x wherein Z is a moiety derived from a reducing saccharide containing from 5 to 6 carbon atoms, preferably a glucose, galactose, glucosyl, or galactosyl residue or mixtures thereof; R is a hydrophobic group selected from the group consisting of alkyl or alkyl phenyl groups or mixtures thereof in which said alkyl groups contain from 8 to 18 carbon atoms, preferably from 12 to 14 carbon atoms, said alkyl group being either saturated or unsaturated and said alkyl or phenyl groups containing from 0 to 3 hydroxy groups, R' is ethylene, propylene and/or glyceryl, t is from 0 to 30, preferably 0 to 10, most preferably 0; wherein x is a number from 1.5 to 10, preferably 1.5 to 4, most preferably 1.6 to 2.7; and
• (2) a mixture of anionic cosurfactants neutralized with one or more cationic moieties consisting essentially of:

  • (a) from 1% to 95%, preferably from 10% to 50%, of a water-soluble alkylbenzene sulfonate in which the alkyl group contins from 10 to 13 carbon atoms, and
  • (b) from 5% to 99%, preferably from 50-90%, of a cosurfactant selected from the group consisting of an alkyl glyceryl ether sulfonate in which the alkyl group contains from 8 to 18 carbon atoms, an alphaolefin sulfonate in which the olefin group contains from 10 to 18 carbon atoms, an alkyl polyethoxylate carboxylate in which the alkyl group contains from 10 to 18 carbon atoms, and the polyethoxylate chain contains from 2 to 6 ethoxylate groups, and mixtures thereof.

It has surprisingly been found that the cosurfactants interact with the alkylpolysaccharide surfactant of this invention to provide a relatively stable foam which is readily rinsed.

Description of the preferred embodiments

The alkylpolysaccharide surfactant

The alkylpolysaccharides are those having a hydrophobic group containing from 8 to 18 carbon atoms, preferably from 10 to 16 carbon atoms, most preferably from 12 to 14 carbon atoms, and a polysaccharide hydrophilic group containing from 1.5 to 10, preferably from 1.5 to 4, most preferably from 1.6 to 2.7 saccharide units (e.g., galactoside, glucoside, fructoside, glucosyl, fructosyl and/or galactosyl units). Mixtures of saccharide moieties may be used in the alkyl polysaccharide surfactants. The number x indicates the number of saccharide units in a particular alkylpolysaccharide surfactant. For a particular alkylpolysaccharide molecule x can only assume integral values. In any physical sample of alkylpolysaccharide surfactants there will in general be molecules having different x values. The physical sample can be characterized by the average value of x and this average value can assume non-integral values. In this specification the values of x are to be understood to be average values. The hydrophobic group (R) can be attached at the 2-, 3-, or 4-positions rather than at the 1-position, (thus giving e.g. a glucosyl or galactosyl as opposed to a glucoside or galactoside). However, attachment through the 1-position, i.e., glucosides, galactosides, fructosides, etc., is preferred. In the preferred product the additional saccharide units are predominately attached to the previous saccharide unit's 2-position. Attachment through the 3-, 4-, and 6-positions can also occur.

Optionally and less desirably there can be a polyalkoxide chain joining the hydrophobic moiety (R) and the polysaccharide-chain. The preferred alkoxide moiety is ethoxide.

Typical hydrophobic groups include alkyl groups, either saturated or unsaturated, branched or unbranched containing from 8 to 18, preferably from 10 to 16 carbon atoms. Preferably, the alkyl group is a straight chain saturated alkyl group. The alkyl group can contain up to 3 hydroxy groups and/or the polyalkoxide chain can contain up to 30, preferably less than 10, most preferably 0, alkoxide moieties.

Suitable alkyl polysaccharides are decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl, di-, tri-, tetra-, penta-, and hexaglucosides, galactosides, lactosides, fructosides, fructosyls, lactosyls, glucosyls and/or galactosyls and mixtures thereof.

The alkylmonosaccharides are relatively less soluble in water than the higher alkylpolysaccharides. When used in admixture with alkylpolysaccharides, the alkylmonosaccharides are solubilized to some extent. The use of alkylmonosaccharides in admixture with alkylpolysaccharides is a preferred mode of carrying out the invention. Suitable mixtures include coconut alkyl, di-, tri-, tetra-, and pentaglucosides and tallow alkyl tetra-, penta-, and hexaglucosides.

The preferred alkyl polysaccharides are alkyl polyglucosides having the formula

wherein Z is derived from glucose, R² is a hydrophobic group selected from the group consisting of alkyl, alkylphenyl, hydroxyalkyl, hydroxyalkylphenyl, and mixtures thereof in which said alkyl groups contain from 10 to 18, preferably from 12 to 14 carbon atoms; n is 2 or 3, preferably 2, t is from 0 to 10, preferably 0; and x is from 1.5 to 8, preferably from 1.5 to 4, most preferably from 1.6 to 2.7. To prepare these compounds a long chain alcohol (R²0H) can be reacted with glucose, in the presence of an acid catalyst to form the desired glucoside. Alternatively the alkylpolyglucosides can be prepared by a two step procedure in which a short chain alcohol (C_l-₆) is reacted with glucose or a polyglucoside (x=2 to 4) to yield a short chain alkyl glucoside (x=₁ to 4) which can in turn be reacted with a longer chain alcohol (R²0H) to displace the short chain alcohol and obtain the desired alkylpolyglucoside. If this two step procedure is used, the short chain alkylglucoside content of the final alkylpolyglucoside material should be less than 50%, preferably less than 10%, more preferably less than 5%, most preferably 0% of the alkylpolyglucoside.

The amount of unreacted alcohol (the free fatty alcohol content) in the desired alkylpolysaccharide surfactant is preferably less than about 2%, more preferably less than 0.5% by weight of the total of the alkyl polysaccharide plus unreacted alcohol. The amount of alkylmonosaccharide is 20% to 70%, preferably 30% to 60%, most preferably 30% to 50% by weight of the total of the alkylpolysaccharide. For some uses it is desirable to have the alkylmonosaccharide content less than about 10%.

As used herein, "alkylpolysaccharide surfactant" is intended to represent both the preferred glucose and galactose derived curfactants and the less preferred alkylpolysaccharide surfactants. Throughout this specification, "alkylglucoside" is used to include alkylglycosides because the stereochemistry of the saccharide moiety is changed during the preparation reaction.

The anionic cosurfactants

Anionic cosurfactants can be selected from the group consisting of sulfonates, carboxylates and mixtures thereof. The cosurfactants are neutralized with a cationic moiety or moieties selected from the group consisting of alkali metal, e.g. sodium or potassium, alkaline earth metal, e.g. calcium or magnesium, ammonium, substituted ammonium, including mono-, di-, or tri-, ethanolammonium cations. Mixtures of cations can be desirable. The anionic cosurfactants useful in the present invention all have detergent properties and are all water-soluble or dispersible in water.

Alkylbenzene sulfonates

One of the cosurfactants for use in this invention is an alkylbenzene sulfonate. The alkyl group can be either saturated or unsaturated, branched or straight chain and is optionally substituted with a hydroxy group. Middle phenyl positions are generally preferred for volume of foaming in light soil conditions. However, in heavier soil conditions, phenyl attachment at the 1- or 2- position is preferred.

The preferred alkylbenzene sulfonates contain a straight alkyl chain containing from 10 to 13 carbon atoms, and the cation is sodium, potassium, ammonium, mono-, di-, or triethanolammonium, calcium or magnesium and mixtures thereof. Magnesium is the preferred cationic moiety. These same cations are preferred for other anionic surfactants and ingredients. The magnesium alkylbenzene sulfonates where the phenyl group is attached near the middle of the alkyl chain are surprisingly better than the ones with the phenyl near the end of the chain when the polysaccharide chain averages greater than about 3 saccharide units. Suitable alkylbenzene sulfonates include C" alkylbenzene sulfonates with low 2-phenyl content.

The alkylbenzene sulfonate cosurfactant is desirable in the foaming compositions of the invention since the foams produced therewith are exceptionally stable, have a large volume, rinse quickly, and do not have a "slippery" feel. These compositions are particularly desirable for industrial and commercial processes as discussed hereinafter. The volume of foam produced using the alkylbenzene sulfonate cosurfactant is larger than for any other cosurfactant.

Soap

Other preferred cosurfactants for use in this invention are carboxylates, e.g. fatty acid soaps and similar surfactants. The soaps can be saturated or unsaturated and can contain various substituents such as hydroxy groups and alpha- sulfonate groups. Preferably, the hydrophobic portion of the soap is a straight chain saturated or unsaturated hydrocarbon. The hydrophobic portion of the soap usually contains from 6 to 30 carbon atoms, preferably from 10 to 18 carbon atoms. The use of carboxylate cosurfactants is especially valuable since the alkylpolysaccharide surfactants are exceptional lime soap dispersers.

The cationic moiety (M) for carboxylate cosurfactants is selected from the group consisting of alkali metal, for example, sodium or potassium, alkaline earth metal, for example, calcium or magnesium, ammonium, or substituted ammonium, including mono-, di-, or triethanolammonium cations. Mixtures of cations can be desirable.

In addition to the preferred alkylbenzene sulfonate and soap cosurfactants many other surfactants which contain sulfonate or carboxylate groups can be used in the foaming compositions of the invention. Generally the use of these latter cosurfactants produces less foam volume than does the use of the preferred cosurfactants. However, the alkylpolysaccharide surfactant stabilizes the foams which are produced and allows the foams to be rinsed more quickly.

One group of cosurfactants that are of interest because of their superior detergency are the zwitterionic detergents which contain both a cationic group, either ammonium, phosphonium, sulfonium or mixtures thereof and a sulfonate or carboxylate group. Preferably there are at least about four atoms separating the cationic and anionic groups. Suitable zwitterionic surfactants are disclosed in U.S. Patents 4,159,277; 3,928,251; 3,925,262; 3,929,678; 3,227,749; 3,539,521; 3,383,321; 3,390,094; and 3,239,560. Such cosurfactants are especially desirable for shampoos.

Another group of cosurfactants are the amphoteric detergents which have the same general structure as the zwitterionic surfactants but with an amine group instead of the quaternary ammonium group.

Yet other cosurfactants are the alkyl (paraffin or olefin) sulfonates, preferably with a more central hydrophilic group, containing from 6 to 30 carbon atoms. Compositions containing these cosurfactants produce the least volume of foam, if that is desired. The hydrophobic group can contain up to about 10 hydroxy groups and/or ether linkages. Examples include C₁₄-₁₅ paraffin sulfonates and C,₄_,₆ olefin sulfonates.

Still another cosurfactant is a soap structure containing up to about 10 ether linkages in the chain and from about 1 to about 4 carbon atoms between ether linkages with from about 6 to about 30 carbon atoms in a terminal portion containing no ether linkages.

The preferred alkylpolyglucosides that contain an average of from 1.5 to 4 glucoside units, preferably from 1.6 to 2.7 glucoside units; less than 50% short chain alkylpolyglucosides; less than 10%, preferably less than 2%, most preferably less than 0.5% unreacted fatty alcohol, increase the sudsing ability of conventional sulfate detergent cosurfactants, especially alkyl sulfate and alkyl polyether sulfate cosurfactants having the formula:

wherein R³ is an alkyl or hydroxyalkyl group containing from 8 to 18 carbon atoms, n is 2 or 3, t can vary from 0 to 30, and M is a cationic moiety as defined above, the cosurfactant being water soluble or dispersible.

Such compositions have improved suds mileage as compared to compositions containing only the alkyl benzene sulfonate cosurfactant and the alkylpolysaccharide surfactant.

Mixtures of alkylbenzene sulfonate and/or the soap cosurfactant and the alkylpolysaccharide surfactant can be used at levels of from 0.01 % to 95%, in ratios of cosurfactant to alkylpolysaccharide of from 10:1 to 1:10, in water with agitation to provide foams. These foams are relatively stable and, if not disturbed, can exist for several days. Furthermore, the foam has structural integrity and does not spread out. The foams prepared using mixtures of alkylbenzene sulfonate and the alkylpolysaccharide are unique in that they do not have a "slippery" feel. All of the foams rinse quickly.

The unusual properties of the foams of this invention make them valuable for use not only in soap bars, bubble baths, shaving creams, laundry, dishwashing, and washing hair, where a good volume of stable suds and quick rinsability are desirable, but also in a large number of fields unrelated to detergency.

The compositions of this invention are particularly valuable for use in the "foam" or "mist" well drilling processes in which the foam is used to carry water and/or soil particles to the surface of the bore hole. A description of such a drilling method can be found in U.S. Patents 3,303,896; 3,111,178; 3,130,798; and 3,215,200. In such a process, the surfactants are present at a level of from 0.01 % to 5%, preferably from 0.01 % to 2%, most preferably from 0.05% to 0.5%. The preferred cosurfactant is an alkylbenzene sulfonate.

The compositions of this invention are also of considerable value in fire fighting or fire prevention processes where a stable foam is used to extinguish a flame or sparks by cutting off the oxygen supply. This includes fire fighting and foaming runways for crash-landings as disclosed in U.S. Patents 2,514,310; 3,186,943; 3,422,011; 3,457,172; 3,479,285; and 3,541,010. Concentrations of from 0.1% to 5% are useful.

The compositions of this invention are also especially valuable in the field of preparing gypsum board, plastic, and resin foams. The foams of this invention provide a stable relatively thick structure permitting solidification of the resins, plastics, cellulosic particles, etc., into stable foam structures having light densities, thick cell walls and good structural integrity. Examples of forming processes which utilize foaming agents are described in U.S. Patents 3,669,898; 4,907,982; 4,423,720; and 4,423,720.

The flotation of minerals so as to concentrate the mineral values, e.g., in the foam (beneficiation), can be carried out advantageously using the compositions and processes of this invention. Such processes are described in U.S. Patents 3,147,644; 4,139,482; 4,139,481; 4,138,350; 4,090,972; and 3,640,862.

A special advantage of the compositions of this invention involves making use of their exceptional stability to provide temporary insulation for plants when freezing conditions are expected. An alkylbenzene sulfonate is the preferred cosurfactant and the foam can be applied to the foliage etc., of the plants. Such a process is disclosed in U.S. Patent 3,669,898.

The range of utilities which are possible with the compositions of this invention include all of the above and many more.

Typical compositions for use as light duty liquid detergent compositions in washing dishes comprise from 5% to 50%, preferably from 10% to 40% of the mixture of surfactants disclosed hereinbefore. From 1% to 50% of a solvent selected from the group consisting of C_'-₃ alkanols, C_1-3 alkanolamines, C₂-₄ polyols, mixtures thereof, and the balance water. It is a special advantage of the compositions of this invention that they can be made in concentrated form (up to 50% by wt. of the mixture of surfactants) with only very low levels of organic solvents and without the addition of expensive hydrotropic materials. Additional suds boosters or builders such as trialkyl amine oxides and fatty acid amides can also be used in amounts up to 20%. Fatty alcohols should not be used.

Shampoo compositions comprise from about 1% to about 95%, preferably from 5% to 20% of the mixture of surfactants mentioned hereinbefore, from 1% to 5% of an alkanol amide, from 0.5% to 3% of a polymeric thickener, and the balance water. It is a special advantage of the shampoos that they rinse quickly and readily.

Additional ingredients

The compositions of this invention can utilize other compatible ingredients, including other surfactants, in addition to the mixture of surfactants herein disclosed. In detergent compositions the compositions can contain any of the well known ingredients including minor amounts of other surfactants, detergency builders, soil suspending agents, brighteners, abrasives, dyes, fabric conditioning agents, hair conditioning agents, hydrotropes, solvents, fillers, clays, perfumes, etc. Suitable ingredients are disclosed in U.S. Patents 4,166,039-Wise; 4,157,978-Llenado; 4,056,481-Tape; 3,049,586-Collier; 4,035,257-Cherney; 4,019,998-Benson et al; 4,000,080―Bartolotta et al; and 3,983,078-Collins. The shampoo compositions of this invention can contain any of the additional ingredients known to the art to be suitable for use in shampoos. Listings of suitable additional ingredients, including low levels of other surfactants can be found in U.S. Patents 4,089,945; 3,987,161; and 3,962,418..

Of special interest are ingredients which modify the feel of aqueous solutions containing the foaming compositions of this invention. For example, raising the pH to above 8.5 by alkaline materials or incorporating the tertiary alcohols of EP-A-0 049 546. Such ingredients are desirable for some consumers since the solutions do not have the normal "soapy" feel associated with surfactant solutions.

The following nonlimiting examples illustrate the foaming compositions of the present invention.

The relative volume of suds in ml. is determined by the following test procedure:

100 ml of the test solution at 44.5°C is placed in a 500 ml graduated cylinder: the solution is agitated by repeated inversion of the graduated cylinder until the amount of suds in the cylinder does not increase with further agitation. Suds height is measured directly on the cylinder scale making allowance for the height of liquid remaining in the cylinder. The test solution is made by adding the test product to water having a hardness of 0.12 gram per liter (Ca/Mg=_3/1).

Example I

Ammonium C_11.2 linear alkyl benzene sulfonate was admixed with C₁₂ alkylpolyglucoside G_3.5 in a ratio of about 2: 1. The mixture was used at a level of 400 ppm in city water. The initial suds volume was more than 300 ml., but after the addition of about 1.25 grams of a standard grease soil per 200 ml. of wash solution, the suds had disappeared. Substitution of a sodium C₁₂-₁₆ alkyl glyceryl ether sulfonate for 25% and 40% of the mixture extended the point at which there was no suds to 1.5 and 1.75 grams of soil per 200 ml. of wash solution respectively.

Similar results are obtained when a sodium, potassium, ammonium, or monoethanolammonium C_12-16 alkylpolyethoxy₃ acetate, or C₁₄-₁₆ olefin sulfonate or mixtures thereof is substituted for at least part of the alkyl glyceryl ether sulfonate.

Example II

A 2:1 mixture of an ammonium C_11.2 alkylbenzene sulfonate and the C,₂-₁₃ alkylpolyglucoside (2-4) (>2% free fatty alcohol) are tested for suds volume as described hereinbefore. The initial suds volume is good, but the SDW (Suds During Washing) grade is not as good as some premium commercial products. Substitution of between 25% and 50% of the mixture with a sodium C₁₂-₁₆ alkyl glyceryl ether sulfonate, or sodium C₁₄-₁₆ olefin sulfonate, or sodium C₁₂-₁₃ alkyl polyethoxylate,₃, acetate increases the SDW grade without lowering the initial sudsing excessively.

Known analytical techniques can be used to determine the structures of the alkylpolysaccharide surfactants hererin; for example, to determine the glycosidic chain length, the amount of butyl glucoside, the free fatty alcohol content, and the level of unreacted polysaccharide. More specifically, gas or liquid chromatography can be used to determine the unreacted alcohol content and the unreacted polysaccharide content respectively. Proton nmr can be used to determine the average glycosidic chain length. The point of attachment of the hydrophilic portion of the molecule to the hydrophobic portion of the molecule can be determined by 13C nmr.

The alkylpolysaccharide surfactants are complex mixtures. Their components vary depending upon the nature of the starting materials and the reaction by which they are prepared. Analytical standards which are useful in calibrating instruments for analyzing the components of a particular alkylpolysaccharide surfactant can be obtained from Calbiochem Behring Co. LaJolla, California. These standards include those for octylglucoside (Calbiochem #494559), decylglucoside (Calbiochem #252715), dodecylmaltoside (Calbiochem #3243555).