Patent Description:
Hand dishwashing compositions should provide good grease cleaning and sudsing. Moreover, during manual dishwashing, whether first added to a sink full of water or added directly to the dish to be washed or to a cleaning implement, the user expects a consistent usage and product performance experience. This includes the viscosity of the product as it directly impacts the user dosing experience, e.g. a low viscous product will flow faster out of the detergent container than a high viscous product will. As such, high viscosities are desired. However, high viscosities typically require higher levels of organic solvents or the addition of structurants. In addition, changes in viscosity, such as due to temperature changes, or even shear rate changes as the container is squeezed, can give rise to a less consistent dosing experience. Moreover, changes in viscosity can give rise to changes in filling volume during packaging of the detergent composition after making. Hence, it is desirable for detergent compositions to have a Newtonian viscosity over as broad a range of shear-rates as possible. At shear rates beyond the Newtonian viscosity plateau, the composition becomes typically more shear thinning.

Hand dishwashing cleaning compositions are typically formulated using alkyl ether sulfate surfactants as the principal anionic surfactant. However, processes to make such alkyl ether sulfate anionic surfactants may result in trace residual amounts of <NUM>,<NUM>-dioxane by-product being present. The amount of <NUM>,<NUM>-dioxane by-product within alkoxylated especially ethoxylated alkyl sulfates can be reduced. Based on recent advances in technology, a further reduction of <NUM>,<NUM>-dioxane by-product can be achieved by subsequent stripping, distillation, evaporation, centrifugation, microwave irradiation, molecular sieving or catalytic or enzymatic degradation steps. An alternative is to use alkyl sulfate anionic surfactants which comprise only low levels of ethoxylation, or even being free of ethoxylation. However, formulating with such alkyl sulfate anionic surfactants lead to poor low temperature stability and can even lead to lower starting viscosities.

Moreover, it is known that formulating the composition using an alkyl sulfate anionic surfactant having little or no alkoxylation results in improved grease removal.

As such, there is a need for a liquid detergent composition comprising alkyl sulfate anionic surfactant which comprises little or no alkoxylation which provides a Newtonian viscosity profile over a larger shear rate range, and where the composition viscosity is less affected by changes in temperature.

<CIT> relates to a process for preparing secondary alkyl sulfate-containing surface active compositions substantially free of unreacted organic matter and water. <CIT> relates to cleaning compositions with improved sudsing profiles, which contain one or more branched and unalkoxylated C6-C14 alkyl sulfate anionic surfactants in combination with one or more linear or branched C4-C11 alkyl or aryl alkoxylated alcohol nonionic surfactants, such cleaning compositions are particularly suitable for use in hand-washing fabrics. <CIT> relates to cleaning compositions with improved sudsing profiles, which contain the combination of one or more branched, unethoxylated C6-C14 alkyl sulfate surfactants with one or more linear, unalkoxylated C6-C18 alkyl sulfate surfactants, such cleaning compositions are particularly suitable for hand-washing dishes or fabrics. <CIT> relates to a light duty liquid detergent composition that includes a C14-C15 alcohol and alcohol ethoxylate sulfate surfactant blend as an efficient and effective foaming agent, the surfactant-based product may be a hand dishwashing liquid, a liquid skin cleanser or any type of cleaning or cleansing product based on surfactants, the light duty liquid detergent composition includes an anionic sulfonate surfactant, an amine oxide, a C14-C15 alcohol sulfate, and a C14-C15 alcohol ethoxylate sulfate. <CIT> relates to a dishwashing detergent composition, including an alkyl sulfate having a branched chain, wherein the refractive index of the dishwashing detergent composition is <NUM> or more to <NUM> or less; the viscosity of the dishwashing detergent composition is <NUM> mPa·s or more to <NUM> mPa·s or less; and the dishwashing detergent composition includes the alkyl sulfate in a content of <NUM>% by mass or more to <NUM>% by mass or less, based on the total amount of the dishwashing detergent composition. <CIT> relates to cleaning compositions with improved sudsing profiles, which contain the combination of one or more branched, unethoxylated C6-C14 alkyl sulphate surfactants with one or more linear, unalkoxylated C6-C18 alkyl sulfate surfactants, the cleaning compositions are particularly suitable for hand-washing dishes or fabrics.

The present invention relates to a liquid hand dishwashing cleaning composition comprising from <NUM>% to <NUM>% by weight of the total composition of a surfactant system, wherein the surfactant system comprises an anionic surfactant and a co-surfactant, wherein the surfactant system comprises at least <NUM>% by weight of the surfactant system of anionic surfactant, wherein the anionic surfactant comprises at least <NUM>% by weight of the anionic surfactant of alkyl sulfate anionic surfactant, wherein the alkyl sulfate anionic surfactant comprises branched alkyl sulfate anionic surfactant such that the alkyl sulfate anionic surfactant has an average degree of branching of from <NUM>% to <NUM>%, wherein: the branched alkyl sulfate anionic surfactant comprises: at least <NUM>% by weight of the branched alkyl sulfate anionic surfactant of C2-branched alkyl sulfate anionic surfactant and at most <NUM>% by weight of the branched alkyl sulfate anionic surfactant of non-C2-branched alkyl sulfate anionic surfactant; the alkyl sulfate anionic surfactant has an alkyl chain comprising an average of from <NUM> to <NUM> carbon atoms; and the alkyl sulfate anionic surfactant has an average degree of alkoxylation of less than <NUM>, wherein the co-surfactant is selected from the group consisting of an amphoteric surfactant, a zwitterionic surfactant, and mixtures thereof, and the weight ratio of the anionic surfactant to the co-surfactant is from <NUM>:<NUM> to <NUM>:<NUM>.

It has been found that a liquid hand dishwashing detergent composition that comprises branched alkyl sulphate anionic surfactant with an average degree of alkoxylation of less than <NUM> and with the specific alkyl branching distribution as described herein, results in a composition that has a viscosity which is Newtonian over a larger shear rate range, which is also less sensitive to changes in temperature.

The term "comprising" as used herein means that steps and ingredients other than those specifically mentioned can be added. This term encompasses the terms "consisting of" and "consisting essentially of. " The compositions of the present invention can comprise, consist of, and consist essentially of the essential elements and limitations of the invention described herein, as well as any of the additional or optional ingredients, components, steps, or limitations described herein.

The term "dishware" as used herein includes cookware and tableware made from, by non-limiting examples, ceramic, china, metal, glass, plastic (e.g., polyethylene, polypropylene, polystyrene, etc.) and wood.

The term "grease" or "greasy" as used herein means materials comprising at least in part (i.e., at least <NUM> wt% by weight of the grease) saturated and unsaturated fats and oils, preferably oils and fats derived from animal sources such as beef, pig and/or chicken.

The terms "include", "includes" and "including" are meant to be non-limiting.

The term "particulate soils" as used herein means inorganic and especially organic, solid soil particles, especially food particles, such as for non-limiting examples: finely divided elemental carbon, baked grease particle, and meat particles.

The term "sudsing profile" as used herein refers to the properties of a cleaning composition relating to suds character during the dishwashing process. The term "sudsing profile" of a cleaning composition includes suds volume generated upon dissolving and agitation, typically manual agitation, of the cleaning composition in the aqueous washing solution, and the retention of the suds during the dishwashing process. Preferably, hand dishwashing cleaning compositions characterized as having "good sudsing profile" tend to have high suds volume and/or sustained suds volume, particularly during a substantial portion of or for the entire manual dishwashing process. This is important as the consumer uses high suds as an indicator that sufficient cleaning composition has been dosed. Moreover, the consumer also uses the sustained suds volume as an indicator that sufficient active cleaning ingredients (e.g., surfactants) are present, even towards the end of the dishwashing process. The consumer usually renews the washing solution when the sudsing subsides. Thus, a low sudsing cleaning composition will tend to be replaced by the consumer more frequently than is necessary because of the low sudsing level.

It is understood that the test methods that are disclosed in the Test Methods Section of the present application must be used to determine the respective values of the parameters of Applicants' inventions as described and claimed herein.

In all embodiments of the present invention, all percentages are by weight of the total composition, as evident by the context, unless specifically stated otherwise. All ratios are weight ratios, unless specifically stated otherwise, and all measurements are made at <NUM>, unless otherwise designated.

The cleaning composition is a hand dishwashing cleaning composition in liquid form. The cleaning composition is preferably an aqueous cleaning composition. As such, the composition can comprise from <NUM>% to <NUM>%, preferably from <NUM>% to <NUM>%, by weight of the total composition of water.

Preferably, the pH of the composition is from about <NUM> to about <NUM>, preferably from about <NUM> to about <NUM>, or more preferably from about <NUM> to about <NUM>, as measured at <NUM>% dilution in distilled water at <NUM>. The pH of the composition can be adjusted using pH modifying ingredients known in the art.

The composition of the present invention can be Newtonian or non-Newtonian, preferably Newtonian. Preferably, the composition has a viscosity of from <NUM> mPa·s to <NUM>,<NUM> mPa·s, preferably from <NUM> mPa·s to <NUM>,<NUM> mPa·s, more preferably from <NUM> mPa·s to <NUM>,<NUM> mPa·s, or most preferably from <NUM> mPa·s to <NUM>,<NUM> mPa·s, alternatively combinations thereof. The viscosity is measured at <NUM> with a Brookfield RT Viscometer using spindle <NUM> with the RPM of the viscometer adjusted to achieve a torque of between <NUM>% and <NUM>%.

The cleaning composition comprises from <NUM> to <NUM>%, preferably from <NUM>% to <NUM>%, more preferably from <NUM>% to <NUM>%, by weight of the total composition of a surfactant system. The surfactant system comprises an anionic surfactant and a co-surfactant.

For improved sudsing, the surfactant system comprises at least <NUM>%, preferably from <NUM>% to <NUM>%, more preferably from <NUM> to <NUM>% by weight of the surfactant system of the anionic surfactant. The anionic surfactant comprises at least <NUM>%, preferably at least <NUM>%, more preferably at least <NUM>% by weight of the anionic surfactant of alkyl sulfate anionic surfactant. Most preferably, the anionic surfactant consists of alkyl sulfate surfactant, most preferably primary alkyl sulfate anionic surfactant. As such, while the surfactant system may comprise small amounts of further anionic surfactant, including sulfonates such as HLAS, or sulfosuccinate anionic surfactants, the surfactant system preferably comprises no further anionic surfactant beyond the alkyl sulfate anionic surfactant.

The alkyl sulfate anionic surfactant has an alkyl chain comprising an average of from <NUM> to <NUM> carbon atoms, preferably from <NUM> to <NUM> carbon atoms, more preferably from <NUM> to <NUM> carbon atoms.

The alkyl chain of the alkyl sulfated anionic surfactant preferably has a mol fraction of C12 and C13 chains of at least <NUM>%, preferably at least <NUM>%, more preferably at least <NUM>%, most preferably at least <NUM>%. Suds mileage is particularly improved, especially in the presence of greasy soils, when the C13/C12 mol ratio of the alkyl chain is at least <NUM>/<NUM>, preferably from <NUM>/<NUM> to <NUM>/<NUM>, most preferably from <NUM>/<NUM> to <NUM>/<NUM>, while not compromising suds mileage in the presence of particulate soils.

The alkyl sulfate anionic surfactant comprises branched alkyl sulfate anionic surfactant such that the alkyl sulfate anionic surfactant has an average degree of branching of from <NUM>% to <NUM>%. As such, the alkyl sulfate anionic surfactant can comprise a mixture of linear and branched alkyl sulfate anionic surfactant.

The weight average degree of branching for an anionic surfactant mixture can be calculated using the following formula:
The level of branching in the branched alkyl sulfate or alkyl alkoxy sulfate used in the detergent composition is calculated on a molecular basis. Commercially available alkyl sulfate anionic surfactant blends that are sold as "branched" will typically comprise a blend of linear alkyl sulfate as well as branched alkyl sulfate molecules. Commercially available alkyl alkoxy sulfate anionic surfactant blends that are sold as "branched" will typically comprise a blend of linear alkyl sulfate branched alkyl sulfate, as well as linear alkyl alkoxy sulfate branched alkyl alkoxy sulfate molecules. The actual calculation of the degree of branching is done based on the starting alcohol (and alkoxylated alcohols for alkyl alkoxy sulfate blends), rather than on the final sulfated materials, as explained in the weight average degree of branching calculation below: <MAT> wherein x1, x2,. are the weight in grams of each alcohol in the total alcohol mixture of the alcohols which were used as starting material before (alkoxylation and) sulphation to produce the alkyl (alkoxy) sulfate anionic surfactant. In the weight average degree of branching calculation, the weight of the alkyl alcohol used to form the alkyl sulfate anionic surfactant which is not branched is included.

The weight average degree of branching and the distribution of branching can typically be obtained from the technical data sheet for the surfactant or constituent alkyl alcohol. Alternatively, the branching can also be determined through analytical methods known in the art, including capillary gas chromatography with flame ionisation detection on medium polar capillary column, using hexane as the solvent. The weight average degree of branching and the distribution of branching is based on the starting alcohol used to produce the alkyl sulfate anionic surfactant.

The branched alkyl sulfate anionic surfactant comprises C2-branched alkyl sulfate anionic surfactant and optionally non-C2-branched alkyl sulfate anionic surfactant. The branched alkyl sulfate anionic surfactant comprises at least <NUM>%, preferably at least <NUM>%, more preferably at least <NUM>% by weight of the branched alkyl sulfate anionic surfactant of C2-branched alkyl sulfate anionic surfactant and at most <NUM>%, preferably at most <NUM>%, most preferably at most <NUM>% by weight of the branched alkyl sulfate anionic surfactant of non-C2 branched alkyl sulfate anionic surfactant.

C2-branched means the alkyl branching is a single alkyl branching on the alkyl chain of the alkyl sulfate anionic surfactant and is positioned on the C2 position, as measured counting carbon atoms from the sulfate group for non-alkoxylated alkyl sulfate anionic surfactants, or counting from the alkoxy-group furthest from the sulfate group for alkoxylated alkyl sulfate anionic surfactants.

Non-C2 branching means the alkyl chain comprises branching at multiple carbon positions along the alkyl chain backbone, or a single branching group present on a branching position on the alkyl chain other than the C2 position.

The non-C2 branched alkyl sulfate anionic surfactant can comprise less than <NUM>%, preferably less than <NUM>%, more preferably less than <NUM>% by weight of the non-C2 branched alkyl sulfate anionic surfactant of C1-branched alkyl sulfate anionic surfactant, most preferably the non-C2 branched alkyl sulfate anionic surfactant is free of C1-branched alkyl sulfate anionic surfactant.

The non-C2 branched alkyl sulfate anionic surfactant can comprise at least <NUM>%, preferably from <NUM> to <NUM>%, more preferably from <NUM> to <NUM>% by weight of the non-C2 branched alkyl sulfate anionic surfactant of isomers comprising a single branching at a branching position greater than the <NUM>-position. That is, more than <NUM> carbons atoms away from the hydrophilic headgroup, as defined above. The non-C2 branched alkyl sulfate anionic surfactant can comprise from <NUM>% to <NUM>%, preferably from <NUM>% to <NUM>%, more preferably from <NUM>% to <NUM>% by weight of the non-C2 branched alkyl sulfate anionic surfactant of multi branched isomers. The non-C2 branched alkyl sulfate anionic surfactant can comprise from <NUM>% to <NUM>%, preferably from <NUM>% to <NUM>%, more preferably from <NUM>% to <NUM>% by weight of non-C2 branched alkyl sulfate anionic surfactant of cyclic isomers. If present, the acyclic branching groups can be selected from C1 to C5 alkyl groups, and mixtures thereof.

It has been found that formulating the compositions using alkyl sulfate anionic surfactants having the aforementioned branching distribution and reduced to nil ethoxylation results in reduced viscosensitivity to variations in temperature and, as such, a more consistent dosage experience, compared to compositions comprising alkyl sulfate anionic surfactants with a comparative branching distribution. Moreover, the composition maintains a Newtonian viscosity profile for higher shear rates, which means less dosage variation and a more consistent user experience, regardless of how hard the container is squeezed.

Moreover, because of the increased branching relative to fully linear surfactant systems, such compositions require less solvent in order to achieve good physical stability at low temperatures. As such, the compositions can comprise lower levels of organic solvent, of less than <NUM>% by weight of the cleaning composition of organic solvent, while still having good low temperature stability. Higher surfactant branching also provides faster initial suds generation. The weight average branching, described herein, has been found to improve low temperature stability and initial foam generation relative to fully linear surfactant systems.

The alkyl sulfate anionic surfactant has an average degree of alkoxylation of less than <NUM>, and preferably, the alkyl sulfate anionic surfactant is free of alkoxylation. As such, the alkyl sulfate surfactant comprises less than <NUM>% preferably less than <NUM>% by weight of the alkyl sulfate anionic surfactant of an alkoxylated alkyl sulfate surfactant, more preferably wherein the alkyl sulfate anionic surfactant is free of an alkoxylated alkyl sulfate surfactant. If alkoxylated, the alkyl sulfated anionic surfactant is preferably ethoxylated.

The average degree of alkoxylation is the mol average degree of alkoxylation (i.e., mol average alkoxylation degree) of all the alkyl sulfate anionic surfactant. Hence, when calculating the mol average alkoxylation degree, the mols of non-alkoxylated sulfate anionic surfactant are included: <MAT> wherein x1, x2,. are the number of moles of each alkyl (or alkoxy) sulfate anionic surfactant of the mixture and alkoxylation degree is the number of alkoxy groups in each alkyl sulfate anionic surfactant.

Suitable counterions for the anionic surfactant include alkali metal cation earth alkali metal cation, alkanolammonium or ammonium or substituted ammonium, but preferably sodium.

Suitable examples of commercially available alkyl sulfate anionic surfactants include, those derived from alcohols sold under the Neodol® brand-name by Shell, or the Lial®, Isalchem®, and Safol® brand-names by Sasol, or some of the natural alcohols produced by The Procter & Gamble Chemicals company. The alcohols can be blended in order to achieve the desired average alkyl chain, average degree of branching and type of branching distribution according to the invention. Considering the targeted branched alkyl sulfate anionic surfactant according to the invention has a high dominance of C2 branched alkyl sulfate content, preferably the alkyl sulfate anionic surfactant comprises an OXO derived alkyl sulfate anionic surfactant, such as commercially available under the lial and isalchem brandname from the Sasol company, and Neodol from the Shell company, OXO derived alkyl sulfate anionic surfactants comprising branched alkyl sulfate anionic surfactant consisting essentially of C2 branched alkyl sulfate anionic surfactant. OXO alcohols are alcohols that are prepared by adding carbon monoxide (CO) and hydrogen (usually combined together as synthesis gas) to an olefin to obtain an aldehyde using the hydroformylation reaction and then hydrogenating the aldehyde to obtain the alcohol. More preferably the alkyl sulfate anionic surfactant comprises from <NUM>% to <NUM>%, preferably from <NUM>% to <NUM>% by weight of the alkyl sulfate anionic surfactant of OXO-derived alkyl sulfate anionic surfactant, wherein OXO alcohols are alcohols that are prepared by adding carbon monoxide (CO) and hydrogen to an olefin to obtain an aldehyde using the hydroformylation reaction and then hydrogenating the aldehyde to obtain the alcohol. Alternative processes yielding alkyl sulfate anionic surfactants comprising branched alkyl sulfate anionic surfactant with high dominance of C2 branched alkyl sulfate anionic surfactant are also considered suitable for the invention. An example of such an alternative process is described in <CIT> and <CIT>. As such the alkyl sulfate anionic surfactant then comprises at least <NUM>%, preferably from <NUM>% to <NUM>%, more preferably from <NUM>% to <NUM>% by weight of alkyl sulfate anionic surfactant of this alternative process derived alkyl sulfate anionic surfactant, or of a mixture of OXO derived and this alternative process derived alkyl sulfate anionic surfactant.

If ethoxylated alkyl sulfate is present, without wishing to be bound by theory, through tight control of processing conditions and feedstock material compositions, both during alkoxylation especially ethoxylation and sulfation steps, the amount of <NUM>,<NUM>-dioxane by-product within alkoxylated especially ethoxylated alkyl sulfates can be reduced. Based on recent advances in technology, a further reduction of <NUM>,<NUM>-dioxane by-product can be achieved by subsequent stripping, distillation, evaporation, centrifugation, microwave irradiation, molecular sieving or catalytic or enzymatic degradation steps. Processes to control <NUM>,<NUM>-dioxane content within alkoxylated/ethoxylated alkyl sulfates have been described extensively in the art. Alternatively <NUM>,<NUM>-dioxane level control within detergent formulations has also been described in the art through addition of <NUM>,<NUM>-dioxane inhibitors to <NUM>,<NUM>-dioxane comprising formulations, such as <NUM>,<NUM>-dihydro-<NUM>-(<NUM>-morpholinyl)-<NUM>-[<NUM>-(<NUM>-oxo-<NUM>-piperidinyl)-phenyl]-<NUM>-(<NUM>-H)-pyridone, <NUM>-α-hydroxy-<NUM>-oxo stereoisomer-mixtures of cholinic acid, <NUM>-(N- methyl amino)-L-alanine, and mixtures thereof.

In order to improve surfactant packing after dilution and hence improve suds mileage, the surfactant system comprises a co-surfactant in addition to the anionic surfactant.

The co-surfactant is selected from the group consisting of an amphoteric surfactant, a zwitterionic surfactant, and mixtures thereof. The co-surfactant is preferably an amphoteric surfactant, more preferably an amine oxide surfactant.

The weight ratio of anionic surfactant to the co-surfactant is from <NUM>:<NUM> to <NUM>:<NUM>, preferably from <NUM>:<NUM> to <NUM>:<NUM>, more preferably from <NUM>:<NUM> to <NUM>:<NUM>, in order to provide improved grease cleaning, sudsing and viscosity build.

The surfactant system can comprise from <NUM>% to <NUM>%, preferably from <NUM>% to <NUM>%, more preferably from <NUM>% to <NUM>% by weight of the cleaning composition of the co-surfactant. The surfactant system of the cleaning composition of the present invention can comprise from <NUM>% to <NUM>%, preferably from <NUM>% to <NUM>%, more preferably from <NUM>% to <NUM>%, by weight of the surfactant system of the co-surfactant.

The amine oxide surfactant can be linear or branched, though linear are preferred. Suitable linear amine oxides are typically water-soluble, and characterized by the formula R1 - N(R2)(R3) O wherein R1 is a C8-<NUM> alkyl, and the R2 and R3 moieties are selected from the group consisting of C1-<NUM> alkyl groups, C1-<NUM> hydroxyalkyl groups, and mixtures thereof. For instance, R2 and R3 can be selected from the group consisting of: methyl, ethyl, propyl, isopropyl, <NUM>-hydroxethyl, <NUM>-hydroxypropyl and <NUM>-hydroxypropyl, and mixtures thereof, though methyl is preferred for one or both of R2 and R3. The linear amine oxide surfactants in particular may include linear C10-C18 alkyl dimethyl amine oxides and linear C8-C12 alkoxy ethyl dihydroxy ethyl amine oxides.

Preferably, the amine oxide surfactant is selected from the group consisting of: alkyl dimethyl amine oxide, alkyl amido propyl dimethyl amine oxide, and mixtures thereof. Alkyl dimethyl amine oxides are preferred, such as C8-<NUM> alkyl dimethyl amine oxides, or C10-<NUM> alkyl dimethyl amine oxides (such as coco dimethyl amine oxide). Suitable alkyl dimethyl amine oxides include C10 alkyl dimethyl amine oxide surfactant, C10-<NUM> alkyl dimethyl amine oxide surfactant, C12-C14 alkyl dimethyl amine oxide surfactant, and mixtures thereof. C12-C14 alkyl dimethyl amine oxide are particularly preferred. Preferably, the alkyl chain of the alkyl dimethyl amine oxide is a linear alkyl chain, preferably a C12-C14 alkyl chain, more preferably a C12-C14 alkyl chain derived from coconut oil or palm kernel oil.

Alternative suitable amine oxide surfactants include mid-branched amine oxide surfactants. As used herein, "mid-branched" means that the amine oxide has one alkyl moiety having n1 carbon atoms with one alkyl branch on the alkyl moiety having n2 carbon atoms. The alkyl branch is located on the α carbon from the nitrogen on the alkyl moiety. This type of branching for the amine oxide is also known in the art as an internal amine oxide. The total sum of n1 and n2 can be from <NUM> to <NUM> carbon atoms, preferably from <NUM> to <NUM>, and more preferably from <NUM> to <NUM>. The number of carbon atoms for the one alkyl moiety (n1) is preferably the same or similar to the number of carbon atoms as the one alkyl branch (n2) such that the one alkyl moiety and the one alkyl branch are symmetric. As used herein "symmetric" means that | n1 - n2 | is less than or equal to <NUM>, preferably <NUM>, most preferably from <NUM> to <NUM> carbon atoms in at least <NUM> wt%, more preferably at least <NUM> wt% to <NUM> wt% of the mid-branched amine oxides for use herein. The amine oxide further comprises two moieties, independently selected from a C1-<NUM> alkyl, a C1-<NUM> hydroxyalkyl group, or a polyethylene oxide group containing an average of from <NUM> to <NUM> ethylene oxide groups. Preferably, the two moieties are selected from a C1-<NUM> alkyl, more preferably both are selected as C1 alkyl.

Alternatively, the amine oxide surfactant can be a mixture of amine oxides comprising a mixture of low-cut amine oxide and mid-cut amine oxide. The amine oxide of the composition of the invention can then comprises:.

In a preferred low-cut amine oxide for use herein R3 is n-decyl, with preferably both R1 and R2 being methyl. In the mid-cut amine oxide of formula R4R5R6AO, R4 and R5 are preferably both methyl.

Preferably, the amine oxide comprises less than <NUM>%, more preferably less than <NUM>%, by weight of the amine oxide of an amine oxide of formula R7R8R9AO wherein R7 and R8 are selected from hydrogen, C1-C4 alkyls and mixtures thereof and wherein R9 is selected from C8 alkyls and mixtures thereof. Limiting the amount of amine oxides of formula R7R8R9AO improves both physical stability and suds mileage.

Suitable zwitterionic surfactants include betaine surfactants. Such betaine surfactants includes alkyl betaines, alkylamidobetaine, amidazoliniumbetaine, sulphobetaine (INCI Sultaines) as well as the Phosphobetaine, and preferably meets formula (I):.

R<NUM>-[CO-X(CH<NUM>)n]x-N+(R<NUM>)(R<NUM>)-(CH<NUM>)m-[CH(OH)-CH<NUM>]y-Y-.

Preferred betaines are the alkyl betaines of formula (Ila), the alkyl amido propyl betaine of formula (IIb), the sulphobetaines of formula (IIc) and the amido sulphobetaine of formula (IId):.

R<NUM>-N+(CH<NUM>)<NUM>-CH<NUM>COO-     (IIa).

R<NUM>-CO-NH-(CH<NUM>)<NUM>-N+(CH<NUM>)<NUM>-CH<NUM>COO-     (IIb).

R<NUM>-N+(CH<NUM>)<NUM>-CH<NUM>CH(OH)CH<NUM>SO<NUM>-     (IIc).

R<NUM>-CO-NH-(CH<NUM>)<NUM>-N+(CH<NUM>)<NUM>-CH<NUM>CH(OH)CH<NUM>SO<NUM>-     (IId).

in which R1 has the same meaning as in formula (I). Particularly preferred are the carbobetaines [i.e. wherein Y-=COO- in formula (I)] of formulae (IIa) and (IIb), more preferred are the alkylamidobetaine of formula (IIb).

Suitable betaines can be selected from the group consisting or [designated in accordance with INCI]: capryl/capramidopropyl betaine, cetyl betaine, cetyl amidopropyl betaine, cocamidoethyl betaine, cocamidopropyl betaine, cocobetaines, decyl betaine, decyl amidopropyl betaine, hydrogenated tallow betaine / amidopropyl betaine, isostearamidopropyl betaine, lauramidopropyl betaine, lauryl betaine, myristyl amidopropyl betaine, myristyl betaine, oleamidopropyl betaine, oleyl betaine, palmamidopropyl betaine, palmitamidopropyl betaine, palm-kernelamidopropyl betaine, stearamidopropyl betaine, stearyl betaine, tallowamidopropyl betaine, tallow betaine, undecylenamidopropyl betaine, undecyl betaine, and mixtures thereof. Preferred betaines are selected from the group consisting of: cocamidopropyl betaine, cocobetaines, lauramidopropyl betaine, lauryl betaine, myristyl amidopropyl betaine, myristyl betaine, and mixtures thereof. Cocamidopropyl betaine is particularly preferred.

The composition can comprise a nonionic surfactant. The nonionic surfactant is preferably selected from the group consisting of: alkoxylated alkyl alcohol, alkyl polyglucoside, and mixtures thereof, more preferably the nonionic surfactant is selected from alkoxylated alkyl alcohols, most preferably ethoxylated alcohols.

The surfactant system can comprise the nonionic surfactant at a level of from <NUM>% to <NUM>%, preferably from <NUM>% to <NUM>%, more preferably from <NUM>% to <NUM>%, by weight of the surfactant system.

Suitable alkoxylated non-ionic surfactants can be linear or branched, primary or secondary alkyl alkoxylated non-ionic surfactants. The alkoxylated nonionic surfactant can comprise on average of from <NUM> to <NUM>, preferably from <NUM> to <NUM>, more preferably from <NUM> to <NUM> carbon atoms in its alkyl chain.

Alkyl ethoxylated non-ionic surfactant are preferred. Suitable alkyl ethoxylated non-ionic surfactants can comprise an average of from <NUM> to <NUM>, preferably from <NUM> to <NUM>, more preferably from <NUM> to <NUM>, units of ethylene oxide per mole of alcohol. Such alkyl ethoxylated nonionic surfactants can be derived from synthetic alcohols, such as OXO-alcohols and Fisher Tropsh alcohols, or from naturally derived alcohols, or from mixtures thereof. Suitable examples of commercially available alkyl ethoxylate nonionic surfactants include, those derived from synthetic alcohols sold under the Neodol® brand-name by Shell, or the Lial®, Isalchem®, and Safol® brand-names by Sasol, or some of the natural alcohols produced by The Procter & Gamble Chemicals company.

The surfactant system can comprise an alkyl polyglucoside nonionic surfactant. Alkyl polyglucoside nonionic surfactants are typically more sudsing than other nonionic surfactants such as alkyl ethoxlated alcohols, especially in the presence of particulate soils.

A combination of alkylpolyglucoside and alkyl sulfate anionic surfactant has been found to improve polymerized grease removal, suds mileage performance, reduced viscosity variation with changes in the surfactant and/or the surfactant system, and a more sustained Newtonian rheology across a wider surfactant active level range.

The alkyl poly glucoside surfactant can be selected from C6-C18 alkyl polyglucoside surfactant. The alkyl polyglucoside surfactant can have a number average degree of polymerization of from <NUM> to <NUM>, preferably from <NUM> to <NUM>, more preferably from <NUM> to <NUM>. The alkyl polyglucoside surfactant can comprise a blend of short chain alkyl polyglucoside surfactant having an alkyl chain comprising <NUM> carbon atoms or less, and mid to long chain alkyl polyglucoside surfactant having an alkyl chain comprising greater than <NUM> carbon atoms to <NUM> carbon atoms, preferably from <NUM> to <NUM> carbon atoms.

Short chain alkyl polyglucoside surfactants have a monomodal chain length distribution between C8-C10, mid to long chain alkyl polyglucoside surfactants have a monomodal chain length distribution between C10-C18, while mid chain alkyl polyglucoside surfactants have a monomodal chain length distribution between C12-C14. In contrast, C8 to C18 alkyl polyglucoside surfactants typically have a monomodal distribution of alkyl chains between C8 and C18, as with C8 to C16 and the like. As such, a combination of short chain alkyl polyglucoside surfactants with mid to long chain or mid chain alkyl polyglucoside surfactants have a broader distribution of chain lengths, or even a bimodal distribution, than non-blended C8 to C18 alkyl polyglucoside surfactants. Preferably, the weight ratio of short chain alkyl polyglucoside surfactant to long chain alkyl polyglucoside surfactant is from <NUM>:<NUM> to <NUM>:<NUM>, preferably from <NUM>:<NUM> to <NUM>:<NUM>, more preferably from <NUM>:<NUM> to <NUM>:<NUM>. It has been found that a blend of such short chain alkyl polyglucoside surfactant and long chain alkyl polyglucoside surfactant results in faster dissolution of the detergent solution in water and improved initial sudsing, in combination with improved suds stability.

The anionic surfactant and alkyl polyglucoside surfactant can be present at a weight ratio of from greater than <NUM>:<NUM> to <NUM>:<NUM>, preferably from <NUM>:<NUM> to <NUM>:<NUM>, more preferably from <NUM>:<NUM> to <NUM>:<NUM>
C8-C16 alkyl polyglucosides are commercially available from several suppliers (e.g., Simusol® surfactants from Seppic Corporation; and Glucopon® <NUM> CSUP, Glucopon® <NUM> EC, Glucopon® <NUM> CSUP/MB, and Glucopon® <NUM> EC/MB, from BASF Corporation). Glucopon® 215UP is a preferred short chain APG surfactant. Glucopon® 600CSUP is a preferred mid to long chain APG surfactant.

The composition can comprise further ingredients such as those selected from: amphiphilic alkoxylated polyalkyleneimines, cyclic polyamines, triblock copolymers, salts, hydrotropes, organic solvents, other adjunct ingredients such as those described herein, and mixtures thereof.

The composition of the present invention may further comprise from <NUM>% to <NUM>%, preferably from <NUM>% to <NUM>% by weight of the total composition of an amphiphilic polymer. Suitable amphiphilic polymers can be selected from the group consisting of: amphiphilic alkoxylated polyalkyleneimine and mixtures thereof. The amphiphilic alkoxylated polyalkyleneimine polymer has been found to reduce gel formation on the hard surfaces to be cleaned when the liquid composition is added directly to a cleaning implement (such as a sponge) before cleaning and consequently brought in contact with heavily greased surfaces, especially when the cleaning implement comprises a low amount to nil water such as when light pre-wetted sponges are used.

A preferred amphiphilic alkoxylated polyethyleneimine polymer has the general structure of formula (I):
<CHM>
wherein the polyethyleneimine backbone has a weight average molecular weight of <NUM>, n of formula (I) has an average of <NUM>, m of formula (I) has an average of <NUM> and R of formula (I) is selected from hydrogen, a C<NUM>-C<NUM> alkyl and mixtures thereof, preferably hydrogen. The degree of permanent quaternization of formula (I) may be from <NUM>% to <NUM>% of the polyethyleneimine backbone nitrogen atoms. The molecular weight of this amphiphilic alkoxylated polyethyleneimine polymer preferably is between <NUM>,<NUM> and <NUM>,<NUM> Da.

More preferably, the amphiphilic alkoxylated polyethyleneimine polymer has the general structure of formula (I) but wherein the polyethyleneimine backbone has a weight average molecular weight of <NUM> Da, n of Formula (I) has an average of <NUM>, m of Formula (I) has an average of <NUM> and R of Formula (I) is selected from hydrogen, a C<NUM>-C<NUM> alkyl and mixtures thereof, preferably hydrogen. The degree of permanent quaternization of Formula (I) may be from <NUM>% to <NUM>% of the polyethyleneimine backbone nitrogen atoms and is preferably <NUM>%. The molecular weight of this amphiphilic alkoxylated polyethyleneimine polymer preferably is between <NUM>,<NUM> and <NUM>,<NUM>, most preferably <NUM>,<NUM> Da.

The amphiphilic alkoxylated polyethyleneimine polymers can be made by the methods described in more detail in <CIT>.

The composition can comprise a cyclic polyamine having amine functionalities that helps cleaning. The composition of the invention preferably comprises from <NUM>% to <NUM>%, more preferably from <NUM>% to <NUM>%, and especially from <NUM>% to <NUM>%, by weight of the composition, of the cyclic polyamine.

The cyclic polyamine has at least two primary amine functionalities. The primary amines can be in any position in the cyclic amine but it has been found that in terms of grease cleaning, better performance is obtained when the primary amines are in positions <NUM>,<NUM>. It has also been found that cyclic amines in which one of the substituents is -CH3 and the rest are H provided for improved grease cleaning performance.

Accordingly, the most preferred cyclic polyamine for use with the cleaning composition of the present invention are cyclic polyamine selected from the group consisting of: <NUM>-methylcyclohexane-<NUM>,<NUM>-diamine, <NUM>-methylcyclohexane-<NUM>,<NUM>-diamine and mixtures thereof. These specific cyclic polyamines work to improve suds and grease cleaning profile through-out the dishwashing process when formulated together with the surfactant system of the composition of the present invention.

Suitable cyclic polyamines can be supplied by BASF, under the Baxxodur tradename, with Baxxodur ECX-<NUM> being particularly preferred.

A combination of the cyclic polyamine and magnesium sulphate is particularly preferred. As such, the composition can further comprise magnesium sulphate at a level of from <NUM> % to <NUM> %, preferably from <NUM> % to <NUM> %, more preferably from <NUM> % to <NUM> % by weight of the composition.

The composition of the invention can comprise a triblock copolymer. The triblock co-polymers can be present at a level of from <NUM>% to <NUM>%, preferably from <NUM>% to <NUM>%, more preferably from <NUM>% to <NUM>%, by weight of the total composition. Suitable triblock copolymers include alkylene oxide triblock co-polymers, defined as a triblock co-polymer having alkylene oxide moieties according to Formula (I): (EO)x(PO)y(EO)x, wherein EO represents ethylene oxide, and each x represents the number of EO units within the EO block. Each x can independently be on average of from <NUM> to <NUM>, preferably from <NUM> to <NUM>, more preferably from <NUM> to <NUM>. Preferably x is the same for both EO blocks, wherein the "same" means that the x between the two EO blocks varies within a maximum <NUM> units, preferably within a maximum of <NUM> unit, more preferably both x's are the same number of units. PO represents propylene oxide, and y represents the number of PO units in the PO block. Each y can on average be from between <NUM> to <NUM>, preferably from <NUM> to <NUM>, more preferably from <NUM> to <NUM>.

Preferably the triblock co-polymer has a ratio of y to each x of from <NUM>:<NUM> to <NUM>:<NUM>. The triblock co-polymer preferably has a ratio of y to the average x of <NUM> EO blocks of from <NUM>:<NUM> to <NUM>:<NUM>. Preferably the triblock co-polymer has an average weight percentage of total EO of between <NUM>% and <NUM>% by weight of the tri-block co-polymer. Preferably the triblock co-polymer has an average weight percentage of total PO of between <NUM>% and <NUM>% by weight of the triblock co-polymer. It is understood that the average total weight % of EO and PO for the triblock co-polymer adds up to <NUM>%. The triblock co-polymer can have an average molecular weight of between <NUM> and <NUM>, preferably between <NUM> and <NUM>, more preferably between <NUM> and <NUM>, most preferably between <NUM> and <NUM>. Average molecular weight is determined using a <NUM> NMR spectroscopy (see Thermo scientific application note No. AN52907).

Triblock co-polymers have the basic structure ABA, wherein A and B are different homopolymeric and/or monomeric units. In this case A is ethylene oxide (EO) and B is propylene oxide (PO). Those skilled in the art will recognize the phrase "block copolymers" is synonymous with this definition of "block polymers".

Triblock co-polymers according to Formula (I) with the specific EO/PO/EO arrangement and respective homopolymeric lengths have been found to enhances suds mileage performance of the liquid hand dishwashing detergent composition in the presence of greasy soils and/or suds consistency throughout dilution in the wash process.

Suitable EO-PO-EO triblock co-polymers are commercially available from BASF such as Pluronic® PE series, and from the Dow Chemical Company such as Tergitol™ L series. Particularly preferred triblock co-polymer from BASF are sold under the tradenames Pluronic® PE6400 (MW ca <NUM>, ca 40wt% EO) and Pluronic® PE <NUM> (MW ca <NUM>, <NUM> wt% EO). Particularly preferred triblock co-polymer from the Dow Chemical Company is sold under the tradename Tergitol™ L64 (MW ca <NUM>, ca <NUM> wt% EO).

Preferred triblock co-polymers are readily biodegradable under aerobic conditions.

The composition of the present invention may further comprise at least one active selected from the group consisting of: salt, hydrotrope, organic solvent, and mixtures thereof.

The composition of the present invention may comprise from <NUM>% to <NUM>%, preferably from <NUM>% to <NUM>%, or more preferably from <NUM>% to <NUM>%, by weight of the total composition of a salt, preferably a monovalent or divalent inorganic salt, or a mixture thereof, more preferably selected from: sodium chloride, sodium sulfate, and mixtures thereof. Sodium chloride is most preferred.

The composition of the present invention may comprise from <NUM>% to <NUM>%, or preferably from <NUM>% to <NUM>%, or more preferably from <NUM>% to <NUM>% by weight of the total composition of a hydrotrope or a mixture thereof, preferably sodium cumene sulfonate.

The composition can comprise from <NUM>% to <NUM>%, or preferably from <NUM>% to <NUM>%, or more preferably from <NUM>% to <NUM>% by weight of the total composition of an organic solvent. Suitable organic solvents include organic solvents selected from the group consisting of: alcohols, glycols, glycol ethers, and mixtures thereof, preferably alcohols, glycols, and mixtures thereof. Ethanol is the preferred alcohol. Polyalkyleneglycols, especially polypropyleneglycol (PPG), are the preferred glycol. The polypropyleneglycol can have a molecular weight of from <NUM> to <NUM>, preferably from <NUM> to <NUM>, more preferably from <NUM> to <NUM>. The polypropyleneglycol is preferably poly-<NUM>,<NUM>-propyleneglycol.

The cleaning composition may optionally comprise a number of other adjunct ingredients such as builders (preferably citrate), chelants, conditioning polymers, other cleaning polymers, surface modifying polymers, structurants, emollients, humectants, skin rejuvenating actives, enzymes, carboxylic acids, scrubbing particles, perfumes, malodor control agents, pigments, dyes, opacifiers, pearlescent particles, inorganic cations such as alkaline earth metals such as Ca/Mg-ions, antibacterial agents, preservatives, viscosity adjusters (e.g., salt such as NaCl, and other mono-, di- and trivalent salts) and pH adjusters and buffering means (e.g. carboxylic acids such as citric acid, HCl, NaOH, KOH, alkanolamines, carbonates such as sodium carbonates, bicarbonates, sesquicarbonates, and alike).

The compositions of the present invention can be used in methods of manually washing dishware. Suitable methods can include the steps of delivering a composition of the present invention to a volume of water to form a wash solution and immersing the dishware in the solution. The dishware is cleaned with the composition in the presence of water.

Typically from <NUM> to <NUM>, preferably from <NUM> to <NUM> of the detergent composition, preferably in liquid form, can be added to the water to form the wash liquor. The actual amount of detergent composition used will be based on the judgment of the user, and will typically depend upon factors such as the particular product formulation of the detergent composition, including the concentration of active ingredients in the detergent composition, the number of soiled dishes to be cleaned, the degree of soiling on the dishes, and the like.

The detergent composition can be combined with from <NUM> to <NUM>, typically from <NUM> to <NUM> of water to form a wash liquor, such as in a sink. The soiled dishware is immersed in the wash liquor obtained, before scrubbing the soiled surface of the dishware with a cloth, sponge, or similar cleaning implement. The cloth, sponge, or similar cleaning implement is typically contacted with the dishware for a period of time ranged from <NUM> to <NUM> seconds, although the actual time will vary with each application and user preferences.

Optionally, the dishware can be subsequently rinsed. By "rinsing", it is meant herein contacting the dishware cleaned with the process according to the present invention with substantial quantities water. By "substantial quantities", it is meant usually from <NUM> to <NUM>, or under running water.

Alternatively, the composition herein can be applied in its neat form to the dishware to be treated. By "in its neat form", it is meant herein that said composition is applied directly onto the surface to be treated, or onto a cleaning device or implement such as a brush, a sponge, a nonwoven material, or a woven material, without undergoing any significant dilution by the user (immediately) prior to application. "In its neat form", also includes slight dilutions, for instance, arising from the presence of water on the cleaning device, or the addition of water by the consumer to remove the remaining quantities of the composition from a bottle. Therefore, the composition in its neat form includes mixtures having the composition and water at ratios ranging from <NUM>:<NUM> to <NUM>:<NUM>, preferably <NUM>:<NUM> to <NUM>:<NUM>, more preferably <NUM>:<NUM> to <NUM>:<NUM>, even more preferably <NUM>:<NUM> to <NUM>:<NUM> depending on the user habits and the cleaning task.

Such methods of neat application comprise the step of contacting the liquid hand dishwashing detergent composition in its neat form, with the dish. The composition may be poured directly onto the dish from its container. Alternatively, the composition may be applied first to a cleaning device or implement such as a brush, a sponge, a nonwoven material, or a woven material. The cleaning device or implement, and consequently the liquid dishwashing composition in its neat form, is then directly contacted to the surface of each of the soiled dishes, to remove said soiling. The cleaning device or implement is typically contacted with each dish surface for a period of time range from <NUM> to <NUM> seconds, although the actual time of application will depend upon factors such as the degree of soiling of the dish. The contacting of said cleaning device or implement to the dish surface is preferably accompanied by concurrent scrubbing.

Subsequently, the dishware can be rinsed, either by submersing in clean water or under running water.

The viscosity is measured at <NUM> with a Brookfield RT Viscometer using spindle <NUM> with the RPM of the viscometer adjusted to achieve a torque of <NUM>% +/-<NUM>% a Discovery HR-<NUM> Hybrid Rheometer using a flow sweep of shear rate from <NUM> to <NUM>-<NUM>. The maximum shear rate of the Newtonian rheology plateau within the viscosity upon shear rate graph has been defined by the shear rate at which the maximum shear stress is reached.

The effect of branching distribution within the starting alcohol used for the alkyl chain of the alkyl sulfate anionic surfactant on the Newtonian plateau range for the liquid hand dishwashing detergent composition was evaluated using the test method described herein.

Non-alkoxylated C12-C13 alkyl sulfate anionic surfactants were made from the starting alcohols summarized in tables <NUM> and <NUM> and used in the following comparative test. As can be seen from Table <NUM>, alkyl sulfate anionic surfactant A was <NUM>% linear and <NUM>% branched. Alkyl sulfate anionic surfactant B had a similar level of branching (<NUM>% linear and <NUM>% branched). In contrast, the alkyl sulfate anionic surfactant C was essentially linear (<NUM>% linear, <NUM>% branched), and the alkyl sulfate anionic surfactant D has an average degree of branching of over <NUM>% (<NUM>% linear, <NUM>% branched). The resultant branching distribution is given in table <NUM>, with alkyl sulfate anionic surfactant A being of use in compositions of the present invention. In contrast, alkyl sulfate anionic surfactant B had a weight fraction of non-C2-branched alkyl sulfate anionic surfactant which was higher than that required by the present invention. Alkyl sulfate anionic surfactant C had a degree of branching which was below that required by the present invention. Alkyl sulfate anionic surfactant D had a degree of branching which was above that required by the present invention.

Safol <NUM>™ is derived from a Fischer-Tropsh process, while Neodol™ <NUM>, Lial™ <NUM>, and Isalchem™ <NUM> are derived from OXO processes. The natural mid cut alcohols are derived from natural sources.

Hand dishwashing compositions were prepared using the alkyl sulfate anionic surfactants A to D. As such, detergent example <NUM> of Table <NUM>, comprising alkyl sulfate anionic surfactant A was an example according to the invention, while detergent examples A and B were comparative, comprising alkyl sulfate anionic surfactant B and C respectively. Comparative examples C to E comprised alkyl sulfate anionic surfactant D having an average degree of branching above that required by the present invention. For the compositions of example <NUM> and comparative examples A and B, the target viscosity of about <NUM> mPas could be achieved. As can be seen from the viscosity results of table <NUM>, for the compositions comprising alkyl sulfate anionic surfactant D, the target viscosity could only be reached by removing all of the salts and solvents (comparative example E). Hence, the shear rate range for the Newtonian plateau at <NUM> cps could not be measured for comparative examples C and D.

Table <NUM> includes the shear rate at which the Newtonian rheology plateau ends (the higher the better) for the compositions where the target viscosity of about <NUM> mPas could be achieved. From the data it can be seen that compositions of the invention comprising alkyl sulfate anionic surfactants having the required branching distribution results in a Newtonian rheology profile in a broader shear rate range, in comparison to examples A and B which comprised alkyl sulfate anionic surfactants having a branching distribution outside the scope of the invention or a degree of branching below that required by the present scope.

Claim 1:
A liquid hand dishwashing cleaning composition comprising from <NUM>% to <NUM>% by weight of the total composition of a surfactant system, wherein the surfactant system comprises an anionic surfactant and a co-surfactant,
wherein the surfactant system comprises at least <NUM>% by weight of the surfactant system of anionic surfactant, wherein the anionic surfactant comprises at least <NUM>% by weight of the anionic surfactant of alkyl sulfate anionic surfactant, wherein the alkyl sulfate anionic surfactant comprises branched alkyl sulfate anionic surfactant such that the alkyl sulfate anionic surfactant has an average degree of branching of from <NUM>% to <NUM>%, wherein:
a) the branched alkyl sulfate anionic surfactant comprises:
a. at least <NUM>% by weight of the branched alkyl sulfate anionic surfactant of C2-branched alkyl sulfate anionic surfactant and
b. at most <NUM>% by weight of the branched alkyl sulfate anionic surfactant of non-C2-branched alkyl sulfate anionic surfactant;
wherein C2-branched means the alkyl branching is a single alkyl branching on the alkyl chain of the alkyl sulfate anionic surfactant and is positioned on the C2 position, as measured counting carbon atoms from the sulfate group for non-alkoxylated alkyl sulfate anionic surfactants, or counting from the alkoxy-group furthest from the sulfate group for alkoxylated alkyl sulfate anionic surfactants;
b) the alkyl sulfate anionic surfactant has an alkyl chain comprising an average of from <NUM> to <NUM> carbon atoms; and
c) the alkyl sulfate anionic surfactant has an average degree of alkoxylation of less than <NUM>,
wherein the co-surfactant is selected from the group consisting of an amphoteric surfactant, a zwitterionic surfactant, and mixtures thereof, and the weight ratio of the anionic surfactant to the co-surfactant is from <NUM>:<NUM> to <NUM>:<NUM>.