Foaming dishwashing liquid compositions

This invention relates to liquid dishwashing detergent compositions which provide controllable aqueous foams.

Alkylpolyglucosides 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 alkylpolyglucoside surfactants and built liquid detergent compositions containing these surfactants. U.S.Patent 3,219,656 discloses alkylmonoglucosides and suggests their utility as foam stabilisers for other surfactants. Various polyglucoside surfactant structures and processes for making them are disclosed in U.S.Patents 2,974,134; 3,640,998; 3,839,318; 3,314,558; 4,011,389; 4,223,129. Dishwashing compositions containing anionic surfactants, nonionic surfactants and amine oxides or amides are known from Fette, Seifen, Anstrichmittel, Die Ernahungsindustrie 68, 551-556 (1966).

Foam compositions containing an alkylpolysaccharide surfactant, and anionic cosurfactants are described in copending published EP-A-0070074 and EP-A-0070075.

Light duty detergent compositions containing an alkylpolysaccharide, alkylbenzene sulfonate and alkylpo- lyethoxylate sulfate cosurfactants are described in copending published EP-A-0070077.

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

This invention relates to foaming liquid diswhashing detergents comprising 10-50% (by weight of the composition) of a mixture of surfactants comprising

• (1) an alkyl polyglucoside of the formula

  wherein Z is derived from glucose; R² is a hydrophobic saturated alkyl group containing from 12 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 4, preferably from 1.6 to 2.7, and including less than 10% unreacted fatty alcohol and less than 50% short chain alkyl polyglucoside.

• (2) an anionic cosurfactant selected from the group consisting of sulfates, sulfonates, carboxylates and mixtures thereof neutralised with one or more cationic moieties, the weight ratio of (2) to (1) being from 1:10 to 10:1; and
• (3) from 2% to 10% (by weight of the composition) of an auxiliary foam booster selected from the group consisting of

  • (a) amides having the formula

    wherein R⁷ is an alkyl group containing from 8 to 18 carbon atoms and each R⁸ is the same or different and is selected from the group consisting of hydrogen, C_1-3 alkyl, Cl-3alkanol, and -(C₂H₄O-)_1-4H groups and mixtures thereof;

  • (b) amine oxides having the formula:

    wherein R⁴ is an alkyl group containing from 8 to 18, preferably from 12 to 14, carbon atoms, each R⁵ contains two or three carbon atom, b is from 0 to 30, each R⁶ is the same or different and is selected from the group consisting of C_1-3 alkyl, C_1-3 alkanol, and -(C₂H₄O)_1-6H groups and mixtures thereof; and

  • (c) mixtures thereof.

It has surprisingly been found that the cosurfactants interact with the alkylpolyglucoside surfactant to provide a relatively stable foam which is readily rinsed and in particular that gives good suds mileage and "Suds during Washing" values.

The alkylpolyglucoside are those having an alkyl hydrophobic group that is saturated and that contains from 12 to 18 carbon atoms preferably from 12 to 16 carbon atoms. The number indicates the number of saccharide units in a particular alkylpolyglucoside surfactant. For a particular alkylpolyglucoside 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 characterised 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 (R²) can be attached at the 2-, 3-, or 4-positions rather than at the 1- position, (thus giving e.g. a glucosyl as opposed to a glucoside). However, attachment through the 1-position, i.e., glucosides, is preferred. In the preferred product the additional glucoside units are predominately attached to the previous glucoside units'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 (R²) and the polyglucoside chain. The preferred alkoxide moiety is ethoxide.

The alkylmonoglucoside are relatively less soluble in water than the higher alkylpolyglucosides. When used in admixture with alkylpolyglucosides the alkylmonoglucosides are solubilised to some extent. The use of alkylmonoglucosides in admixture with alkylpolyglucosides is a preferred mode of carrying out the invention. Suitable mixtures include coconut alkyl, di-, tri- and, tetraglucosides and tallow alkyl tetraglucosides.

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 alkylpolyglucoside surfactant is preferably less than 2%, more preferably less than 0.5% by weight of the total of the alkylpolyglucoside plus unreacted alcohol. The amount of alkylmonoglucoside is 20% to 70%, preferably 30% to 60%, most preferably 30% to 50% by weight of the total of the alkylpolyglucoside. For some uses it is desirable to have the alkylmonoglucoside content less than 10%.

Throughout this specification, "alkylglucoside" is used to include alkylglycosides because the sterochem- istry of the saccharide moiety is changed during the preparation reaction.

Anionic cosurfactants can be selected from the group consisting of sulfates, sulfonates, carboxylates and mixtures thereof. The cosurfactants are neutralised 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.

One of the cosurfactants for use in this invention can be 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 9 to 25 carbon atoms, preferably 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 polyglucoside chain averages greater than 3 glucosides units. Suitable alkylbenzene sulfonates include C₁₁ alkylbenzene sulfonates with low 2-phenyl content.

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 stabilises 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 ammoniun, 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.

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 10 hydroxy groups and/or ether linkages. Examples include C_14-15 paraffin sulfonates and C₁₄-₁₆ olefin sulfonates.

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

The alkylpolyglucosides can be contaminated with less than 50% short chain alkylpolyglucosides and with less than 10%, preferably less than 2%, most preferably less than 0.5% unreacted fatty alcohol and 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.

The compositions of the invention provide superior suds mileage.

Preferred anionic cosurfactants are alkylbenzene sulfonate, alpha-olefin sulfonate, alkylsulfates, alkylpo- lyethoxylate sulfates an paraffin sulfonates and mixtures thereof. The cationic moieties are selected from the group consisting of sodium, potassium, ammonium, monoethanolammonium, diethanolammonium, triethanolammonium, triethanolammonium, calcium, magnesium and mixtures thereof.

Preferred compositions of this embodiment of the invention comprise from 1% to 95%, preferably 5% to 50% of an akylpolyglucoside surfactant in which the alkyl group contains from 12 to 14 carbon atoms, x is from 1.5 to 4, more preferably 1.5 to 2.7; from 1 % to 95%, preferably from 10% to about 50% of an anionic cosurfactant neutralised with one or more cationic moieties and which is a mixture of

• (1) from 1 % to 95%, preferably from 5% to 50% of an alkyl benzene sulfonate in which the alkyl group contains from 8 to 13 carbon atoms or an alpha-olefin sulfonate in which the olefin group contains from 10 to 18 carbon atoms, or mixtures thereof; and
• (2) from 1% to 95%, preferably from 5% to 50% of an alkyl polyethoxylate sulfate in which the alkyl group contains from 8 to 18 carbon atoms, preferably from 12 to 14 carbon atoms and from one to six ethoxylate moieties and wherein from 1% to 100%, preferably from 10% to 80% of the cationic moieties are magnesium; and wherein the auxiliary foam booster is an amide.

Typical compositions for use as light duty liquid detergent compositions in washing dishes comprise from 10% to 50%, preferably from 10% to 40% of the mixture of surfactants disclosed hereinbefore and from 1 % to 50% of a solvent selected from the group consisting of C₁-₃ alkanols, C₁-₃ 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. Fatty alcohols should not be used.

The compositions of this invention can utilise other compatible ingredients, including other surfactants, in addition to the mixture of cosurfactants herein disclosed.

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:

• 100mi of the test solution at 46.1 °C is placed in a 500ml 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 grams per liter (Ca/Mg=3/1).

Example 1

The following formulas were prepared:

Formulas A, B and C were compared by generating suds with a constant source of agitation under standard conditions [3.785 I (1 gal) water, 46.1°C (115°F) 0.12 g/I hardness in a 11.3 dishpan using a standardised mixture of fat plus protein, carbohydrate and edible acid]. Dinner plates are washed with 4mi of soil on each plate and the suds height is measured after each five plates. 30 plates in total are washed and the integral of the suds height taken over the number of plates washed is reported as the SDW grade (SDW = Suds During Washing).

This shows that the addition of a small amount of these amine oxides dramatically increases the amount of dishes that can be washed. Similar results are obtained when a fatty acid amide, e.g., a coconut fatty acid amide, diethanol amide, and/or isopropanol amide is substituted, at least in part for the specific amide oxides.

Exemple 2

The following formulas were prepared:

The SDW index is the SDW grade for each product as a percentage of the SDW value of a standard commercial product.

The following is an example of particularly preferred compositions. The broad and preferred ranges of ingredients which can be used are given in the second and third columns, respectively, in each example.

Example 3

Known analytical techniques can be used to determine the structures of the alkylpolyglucoside surfactants herein; for example to determine the glycosidic chain length, the amount of butyl glucoside, the free fatty alcohol content, and the level of unreacted polyglucoside. More specifically, gas or liquid chromatrography can be used to determine the unreacted alcohol content and the unreacted polyglucoside 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 alkylpolyglucoside 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 analysing the components of a particular alkylpolyglucoside surfactant can be obtained from Calbiochem Behring Co.Lajolla, California. These standards include those for octylglucoside (Calbiochem #494559), decylglucoside (Calbiochem #252715), dodecylmaltoside (Calbiochem #3243555).