Field of the invention

The present invention is in the field of hard surface cleaning compositions; in particular liquid detergent compositions having foaming and cleaning characteristics in the main wash, yet significant foam reduction during rinse.

Background of the invention

Water is becoming a more and more scarcely available commodity, especially in developing countries, where it is not unusual that people have to walk many kilometres to arrive at a water source. As a result of which, there is an increasing need to save water.

One way of saving water is to reuse the water and another way is to reduce the amount of water being used.

Washing processes, including laundry, dishwashing and other household cleaning processes, require large amounts of water throughout the world. These are daily chores in which the use of water and a detergent cannot be avoided. Consumers usually like to see a lot of foam while washing as they associate foaming with detergent efficiency. However, it's rinsing that often takes a lot of effort and uses excess of water.

The amount of water required for rinse is entirely dependent on the detergent used. Therefore, the use of water can be reduced or controlled based on the detergent.

Thus, it has been a challenge to provide consumers with a cleaning composition that maintains the initial foam while exhibiting an antifoaming effect during rinse.

WO 98/27189 discloses a mildly acid laundry detergent composition for improved protection of fine fabrics during washing and enhanced removal of generated foam during rinsing in hand wash comprising at least one anionic surfactant and/or at least one non-ionic surfactant and a rinse-active pH sensitive foam control agent comprising a fatty acid, whereby upon rinsing, at least a portion of said fatty acid is converted to a soap which functions to suppress foam during rinsing. In this document, the fatty acid may be selected from saturated or unsaturated fatty acids and preferably are lauric, myristic, oleic and stearic, natural coconut, palmitic and tallow fatty acids. However, there is no disclosure that a specific combination of saturated stearic acid and saturated lauric acid is preferred. The composition of W098/27189 also does not disclose the specific surfactant system of the present invention.

JP 2004-203989 discloses a liquid detergent composition for tableware washing comprising 5-50 mass % of a sulfuric ester and/or a sulfonate type anionic surfactant, 1-30 mass % of a specific alkoxylate type nonionic surfactant and an 8-20C saturated and/or unsaturated fatty acid/salt and has pH of 4-8. In this document, the fatty acid may be selected from saturated or unsaturated C8-20 fatty acids. However, there is no disclosure that a specific combination of saturated stearic acid and saturated lauric acid is preferred.

US 6090764 discloses a manual dishwashing detergent composition containing 0.2 to 10% by weight of a glycerol sulfate, 1 to 50% by weight of a C6-22 alkyl sulfate, Ce-22 alkyl ether sulfate, C9-13 alkyl benzene sulfonate or a mixture thereof and 1 to 20% by weight based on the detergent as a whole of an alkyl glucoside. The composition of US 6090764 does not include fatty acids, however very small quantities of soap may be present.

CN 102876483 discloses a low foam easy bleaching liquid detergent composition and its preparation method. The liquid detergent composition comprises 0.1 to 20% unsaturated fatty acid, 0.1 to 5% saturated fatty acids, 0.1 to 5% alkali neutralizing agent, 1 to 25% non-ionic surfactant, 1 to 25% anionic surfactant, 0.5 to 20% of other additives and water. This formulation uses saturated and unsaturated fatty acids to reduce the amount of the liquid detergent wash foam, to solve the problem of difficulty in rinsing. However, there is no disclosure that a specific combination of saturated stearic acid and saturated lauric acid is preferred.

WO 2013/038750 discloses a liquid detergent composition which contains one or more kinds of anionic surfactant selected from the group consisting of polyoxyalkylene alkyl ether sulfuric acid ester salts and alkylbenzene sulfonic acid salts, a fatty acid and/or a salt thereof, an alkanol amine, a carbonate, a nonionic surfactant and water. However, there is no disclosure about the specific combination of saturated fatty acids selected from stearic and lauric acid.

It is therefore an object of the present invention to provide water saving in household process, especially hand dish wash processes.

It is another object of the present invention to provide a liquid detergent that has an antifoaming effect during rinse while maintaining foaming characteristics in the mainwash.

It is a further object of the present invention to provide a liquid detergent composition that uses less water during rinsing in hand dish wash processes.

Surprisingly, it has been found that an antifoaming effect may be obtained only during rinse in hard surface cleaning processes by a liquid detergent comprising a surfactant system of a primary and a secondary surfactant, a combination of saturated fatty acids selected from lauric and stearic acid and a non-ionic surfactant.

Summary of the invention

Accordingly, in a first aspect, the present invention provides a liquid detergent composition comprising 8 to 30% by weight of a surfactant system comprising a primary surfactant of the formula Ri-(OR') _n -0-S03 ^" M ⁺ , wherein: Ri is saturated or unsaturated Cs-Ci6 alkyl chain; R' is ethylene; n is from 1 to 18; M ⁺ is a suitable cation which provides charge neutrality selected from sodium, calcium, potassium and magnesium; and a secondary surfactant selected from alkylbenzene sulphonate and derivatives; and alkyl sulphates; less than or equal to 1 % by weight of a combination of saturated fatty acids selected from lauric and stearic acid; less than or equal to 3% by weight of a non-ionic surfactant; and water.

In a second aspect, the invention provides a process of reducing foam during rinse in dishwashing comprising the steps of applying onto the hard surface in neat or diluted form a liquid composition according to the invention; cleaning the hard surface with a cleaning implement; and rinsing the hard surface.

In a third aspect, the invention provides use of a composition according to the invention for providing anti-foaming activity upon rinse.

In the context of the present invention, the reference to "hard surface" typically means utensils or kitchenware, kitchen tops, kitchen floors, sinks and platforms, floors and bathrooms.

These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the present invention may be utilised in any other aspect of the invention. The word "comprising" is intended to mean "including" but not necessarily "consisting of" or "composed of." In other words, the listed steps or options need not be exhaustive. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about".

Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated.

Detailed description of the invention

In a first aspect, the invention relates to a liquid detergent composition comprising a surfactant system, a combination of fatty acids, a non-ionic surfactant and water. Surfactant System

The liquid detergent composition of the present invention comprises a surfactant system. The surfactant system comprises a primary and a secondary surfactant. Both the primary and the secondary surfactants are selected from anionic surfactants.

Primary surfactant

The primary surfactant of the present invention is a surfactant of the formula:

Ri-(OR') _n -0-S0 ₃ ^" M ⁺ , wherein:

Ri is saturated or unsaturated C8-C16, preferably C12-C14 alkyl chain; preferably, Ri is a saturated Cs-Ci6, more preferably a saturated C12-C14 alkyl chain;

R' is ethylene; n is from 1 to 18; preferably from 1 to 15, more preferably from 1 to 10 , still more preferably from 1 to 5.

M ⁺ is a suitable cation which provides charge neutrality, preferably sodium, calcium, potassium, or magnesium, more preferably a sodium cation.

Preferred primary surfactants are sodium lauryl ether sulphate having 1 to 3 ethylene oxide units per molecule.

Most preferred primary surfactant of the present invention is sodium lauryl ether sulphate having 1 to 2 ethylene oxide units per molecule. Primary surfactant may be present in a concentration of 5 to 95 %, preferably at least 12%, more preferably at least 20%, still more preferably at least 30% but typically not more than 85%, preferably not more than 75%, more preferably not more than 65% , still more preferably not more than 55% by weight of the surfactant system. Secondary surfactant

The secondary surfactant of the present invention may be selected from alkylbenzene sulphonates and derivatives; and alkyl sulphates.

Alkylbenzene sulphonates and derivatives include water-soluble alkali metal salts of organic sulphonates having alkyl radicals typically containing from about 8 to about 22 carbon atoms, preferably 8 to 18 carbon atoms, still more preferably 12 to 15 carbon atoms and may be unsaturated.

Examples include sodium salt of linear alkylbenzene sulphonate, alkyl toluene sulphonate, alkyl xylene sulphonate, alkyl phenol sulphonate, alkyl naphthalene- sulphonate, ammonium diamylnaphthalene-sulphonate and sodium

dinonylnaphthalene-sulphonate and mixtures with olefin sulphonates.

Examples of alkyl sulphates include sodium lauryl sulphate, ammonium lauryl sulphate, diethanolamine(DEA) lauryl sulphate. Suitable examples also includes alkyl sulphates commercially available from natural source with trade names Galaxy 689, Galaxy 780, Galaxy 789, Galaxy 799 SP and from synthetic origin with trade names Safol 23, Dobanol 23A or 23S, Lial 123 S, Alfol 1412S, Empicol LC3, Empicol 075SR.

Preferred secondary surfactants are sodium salt of linear alkylbenzene sulphonate and sodium lauryl sulphate. Most preferred secondary surfactant is sodium salt of linear alkylbenzene sulphonate.

Secondary surfactant may be present in a concentration of 5 to 95 %, preferably at least 12%, more preferably at least 20%, still more preferably at least 30% but typically not more than 85%, preferably not more than 75%, more preferably not more than 65%, still more preferably not more than 55% by weight of the surfactant system.

The surfactant system of the present invention may further comprise an amphoteric surfactant. Suitable surfactants include cocoamidopropyl betaine (CAPB), coco amido propyl amine oxide (CAPAO), cocodiethanol amide (CDEA) and cocomonoethanol amide (CMEA).

Most preferred amphoteric surfactant is cocoamidopropyl betaine.

When present, the amphoteric surfactant is in a concentration of 0.1 to 20%, preferably at least 0.5%, more preferably at least 3%, still more preferably atleast 6% or even more preferably at least 8% but typically not more than 18%, preferably not more than 16%, more preferably not more than 13%, still more preferably not more than 10% by weight of the surfactant system.

The surfactant system is present in the composition in a concentration of 8 to 30%, preferably not less than 15%, more preferably not less than 18%, still more preferably not less than 20% but typically not more than 28%, preferably not more than 27% or even not more than 26% by weight of the composition.

Combination of Fatty Acids

The liquid detergent composition of the present invention comprises a combination of fatty acids.

The combination of fatty acids used in present invention is selected from lauric (C12) and stearic acid (Cis).

Without wishing to be bound by a theory, it is thought that when C12 and C18 fatty acids are used in combination, the chain lengths of these fatty acids have a crucial role on the flash foam and the antifoam activity during rinse. C12 ensures there is no adverse effect on the flash foam of surfactant solution while C18 triggers the antifoam activity only during rinse. Individual fatty acids are found to either kill the surfactant's flash foam or have poor antifoaming activity.

Fatty acids used in the present invention are saturated fatty acids. Saturated lauric (C12) and stearic acid (Cis) are preferred. Unsaturated fatty acids are not preferred in the present invention. Laurie and stearic acid are present in the composition in a ratio of 1 :1.

The fatty acids are present in the composition in a concentration of 0.1 to 1 % by weight, preferably at least 0.5% but typically not more than 0.9%, more preferably not more than 0.8% by weight of the composition.

Non-ionic surfactant

The liquid detergent composition of the present invention comprises a non-ionic surfactant.

The nonionic surfactant of the present invention includes the condensation products of a higher alcohol (e.g., an alkanol containing about 8 to 18 carbon atoms in a straight or branched chain configuration) condensed with about 5 to 30 moles of ethylene oxide, for example, lauryl or myristyl alcohol condensed with about 16 moles of ethylene oxide (EO), tridecanol condensed with about 6 moles of EO, myristyl alcohol condensed with about 10 moles of EO per mole of myristyl alcohol, the condensation product of EO with a cut of coconut fatty alcohol containing a mixture of fatty alcohols with alkyl chains varying from 10 to about 14 carbon atoms in length and wherein the condensate contains either about 6 moles of EO per mole of total alcohol or about 9 moles of EO per mole of alcohol and tallow alcohol ethoxylates containing 6 EO to 1 1 EO per mole of alcohol. Particularly preferred is Lauryl alcohol condensed with 5, 7 and 9 moles of ethylene oxide (Laureth 5, Laureth 7 and Laureth 9).

Condensates of 2 to 30 moles of ethylene oxide with sorbitan mono- and tri-Cio-C2o alkanoic acid esters having a HLB of 8 to 15 also may be employed as the nonionic surfactant. These surfactants are well known and are available from Imperial Chemical Industries under the Tween trade name. Suitable surfactants include polyoxyethylene (4) sorbitan monolaurate, polyoxyethylene (4) sorbitan monostearate, polyoxyethylene (20) sorbitan trioleate and polyoxyethylene (20) sorbitan tristearate.

Preferred non-ionic surfactants of the present invention are Laureth 5, Laureth 7 and Laureth 9.

The non-ionic surfactant is present in the composition in a concentration of 0.1 to to 3% by weight, preferably at least 0.5%, still more preferably at least 1 % but typically not more than 2.5%, more preferably not more than 2% by weight of the composition.

Water

The composition further comprises water. Preferably 60 to 92%, more preferably not less than 62%, still more preferably not less than 65% but typically not more than 85%, more preferably not more than 80%, still more preferably not more than 75% by weight of the composition. Optional Ingredients

The composition according to the invention may contain other ingredients which aid in the cleaning or sensory performance. Compositions according to the invention can also contain, in addition to the ingredients already mentioned, various other optional ingredients such as thickeners, colorants, preservatives, polymers, anti microbial agents, perfumes, pH adjusters, sequesterants, alkalinity agents and hydrotropes. pH of the composition

pH of the composition of the present invention is between 4.5 and 6.5, preferably between 5 and 6.5, more preferably between 5.5 and 6.

Product format

The composition may be used neat or diluted.

For hard surface cleaning or for dishwashing purposes, the composition is typically applied neat directly to the surface. When applied in a diluted form, the composition is preferably diluted with water in a ratio of between 1 :1 to 1 :10

Both manual dishwashing and machine dishwashing are considered in the context of the present invention.

The composition may be packaged in the form of any commercially available bottle for storing the liquid. The bottle containing the liquid can be of different sizes and shapes to accommodate different volumes of the liquid; preferably between 0.25 and 2 L, more preferably between 0.25 and 1.5 L or even between 0.25 and 1 L. The bottle is preferably provided with a dispenser, which enables the consumer an easier mode of dispersion of the liquid. Spray or pump-dispensers may also be used.

Process

In a second aspect, the invention relates to a process of reducing foam during rinse in dishwashing comprising the steps of applying onto the hard surface in neat or diluted form a liquid composition according to the invention, cleaning the hard surface with a cleaning implement; and rinsing the hard surface.

The composition may be applied by any known ways such as by using a scrub, sponge paper, cloth, wipes or any other direct application. The applied composition may be cleaned using a cleaning implement such as a scrub, sponge, paper, cloth or wipes.

In a third aspect, the invention relates to use of a composition according to the invention for providing anti-foaming activity upon rinse. The invention will now be illustrated by means of the following non-limiting examples.

Examples

Materials Table 1

Manufacturer/

Name Chemical /Material Grade

Supplier

Caprylic acid Lab Grade Sigma

Laurie acid Lab Grade SD Fine Chem

Myristic acid Lab Grade Fluka

Palmitic acid Lab Grade Sigma

Fatty Acids Stearic acid Lab Grade SDFine Chem

Oleic acid Lab Grade Sigma

Prifac 5908 Lab Grade CRODA (Hydrogenated topped

palm kernel fatty acids) Non-ionic Laureth 7 (Lauryl alcohol Commercial Galaxy

Surfactant ethoxylates) Surfactants

LAS powder (Linear alkyl Commercial Advance benzene suphonate) Surfactants India (97% active content) Limited

Anionic Surfactant

SLES 2EO (Sodium Commercial Galaxy

Lauryl ether sulfonate)

(70% active content)

CAPB (Cocoamidopropyl Commercial Galaxy

Amphoteric

betaine) (29-31 % active

Surfactant

content)

Methods

Preparing the compositions:

The compositions were prepared in a batch size of 30 grams each. A mixture of the primary and the secondary surfactant was taken in a 50 mL Tarson tube (the

concentrations of the surfactants in the examples have been calculated taking into account the purity of the material). De-mineralized water was added to this mixture and vortexed till the surfactants had dissolved completely. The fatty acid(s) was then added to the mixture and heated to a temperature of 60°C in a water bath (maintained at 65°C). The mixture was stirred in between to ensure homogenous mixing. After complete solubilization of the fatty acid, the mixture was cooled to a temperature of 25 to 30°C, to which the non-ionic surfactant was added and stirred for about 2 to 3 minutes. In compositions with amphoteric surfactant, the amphoteric surfactant was added along with the non-ionic surfactant. The final mixture was allowed to cool before using it for foam volume studies.

Procedure for measurement of foam volume:

For the measurement of foam volume, standard cylinder shake method was used.

6.25 g/L of the test solution was prepared in 24 FH water. 50 mL of the test solution was taken in a 250 mL graduated glass cylinder. The solution was shook by covering the opening of the cylinder and inverting it 10 times. Then the cylinder was placed on a flat surface of a table for 1 minute for the aqueous layer to separate and it was shook once again to even out the foam level. The volume of foam (excluding aliquote water), in mL was measured and recorded as the initial foam volume. To measure the foam in the first and further rinse cycles, the aliquote water was decanted along the sides of the cylinder retaining foam in the cylinder. 50 mL of fresh 24 FH water was added along the sides of the cylinder and the solution was shook and the foam volume measured as mentioned for initial foam measurement above. The cycles were repeated till the foam volume was <10 mL.

Initial foam volume equal to the control or upto 10 mL lesser than the control is considered to be good. Foam volume reduction of <10 mL in the fourth or lower cycles are considered to be good.

Example 1 : Effect of the specific combination of lauric and stearic acid on foam volume In this example, the volume of foam generated in the initial wash and the antifoaming effect during rinse by the composition according to the invention (Ex1 ) is compared to comparative compositions (C2 to C15) comprising various other fatty acids and their combinations. Table 2

Set *S Non- Fatty acid Wat Foam volume per rinse cycle, ml

urf loni wt% Type er Initi 1 2 3 4 5 6 act c wt% al

an Surf foa

t acta m

wt nt

% wt%

C1 18 - - - 82 160 160 145 1 10 60 30 12

C2 18 0.5 0.5 C8 81 147 137 123 83 40 12 <1

0

C3 18 0.5 0.5 C12 81 147 130 1 10 55 19 <1 -

0

C4 18 0.5 0.5 C14 81 120 1 10 80 40 12

<1

0

C5 18 0.5 0.5 C16 81 130 1 10 60 <10 - - -

C6 18 0.5 0.5 C18 81 133 1 13 47 <10 - - -

C7 18 0.5 0.5 C8+C 81 130 130 140 70 30 12

12 <1

0 C8 18 0.5 0.5 C8+C 81 135 130 1 10 50 18

14 <1

0

C9 18 0.5 0.5 C8+C 81 140 140 1 10 70 30 <1 - 16 0

C10 18 0.5 0.5 C8+C 81 130 130 1 10 60 30 <1 - 18 0

C1 1 18 0.5 0.5 C12+ 81 140 120 1 10 70 30 <1 - C14 0

C12 18 0.5 0.5 C12+ 81 130 130 100 50 16 - - C16

Ex1 18 0.5 0.5 C12+ 81 160 150 97 15 <10 - - C18

C13 18 0.5 0.5 C14+ 81 130 1 10 70 26 - - C16 <10

C14 18 0.5 0.5 C14+ 81 130 120 50 <10 - - - C18

C15 18 0.5 0.5 C16+ 81 1 10 100 40 <10 - - - C18

^* 13.50% LAS + 3.94% SLES 2EO + 0.56% CAPB The table above shows that the composition according to the invention (Ex1 ) performs best when compared to any other compositions comprising fatty acids outside the scope of the present invention (C2 to C15). It is noted that Ex1 maintains the same initial foam as the control (C1 ) and requires lesser rinse cycles compared to other compositions.

Example 2: Effect of each component of the composition on foam volume

In this example, the volume of foam generated in the initial wash and the antifoaming effect during rinse by the composition according to the invention (Ex1 ) is compared to comparative combinations (C16 and C17) comprising only one component of the composition. Table 3

*13.50% LAS + 3.94% SLES 2EO + 0.56% CAPB

The table shows that the composition according to the invention performs better with respect to the number of rinse cycles and initial foam volume than the compositions with one of the components missing.

Example 3: Effect of concentration of the fatty acid combination on foam volume This example demonstrates the effect of concentration of the fatty acid combination on the volume of foam generated in the initial wash and the antifoaming effect during rinse. The example compositions Ex1 and Ex2 are compared with comparative compositions C18 and C19 comprising the fatty acid combination in a concentration outside the scope of the invention.

Table 4

Set *Su Non- Fatty acid Wate Foam volume per rinse cycle, m rfac Ionic (C12 + r wt% Initi 1 2 3 4 5 6 tant Surfa C18) al

wt ctant wt% foa

% wt% m

Ex1 18 0.5 0.5 81 160 150 97 15 <10 - -

Ex2 18 0.5 1 80.5 160 160 90 42 <10 - -

C18 18 0.5 2 79.5 1 10 90 56 26 <10 - -

C19 18 0.5 3 78.5 80 60 24 <10 - - - ^* 13.50% LAS + 3.94% SLES 2EO + 0.56% CAPB

The table above shows that best results for initial foam and an antifoaming effect during rinse are obtained at a fatty acid combination concentration within the scope of the present invention. The table also shows that at higher fatty acid combination concentrations, the initial foam is compromised (C18 and C19).

Example 4: Effect of concentration of non-ionic surfactant on foam volume

In this example, compositions according to the invention comprising different concentrations of non-ionic surfactant (Ex1 and Ex3 to Ex5) are compared with comparative compositions having non-ionic surfactant in a concentration outside the scope of the present invention (C20 and C21 ).

Table 5

*13.50% LAS + 3.94% SLES 2EO + 0.56% CAPB

It is inferred from the results of the above table that good initial foam and reduction in foam during rinse are obtained with compositions comprising the non-ionic surfactant in a concentration according to the invention. At concentrations outside the scope of the invention, the compositions appear to result in phase separation. Example 5: Effect of the specific combination of fatty acids on foam volume in comparison to commercially available fatty acid mixtures

In this example, the specific combination of fatty acids according to the invention (Ex1 ) is compared to a composition comprising commercially available mixtures of natural and distilled fatty acids such as coconut fatty acid and palm kernel fatty acid (C22).

Table 6

*13.50% LAS + 3.94% SLES 2EO + 0.56% CAPB

The above table shows that the good initial foam generated by Ex1 and the antifoaming effect during rinse is still not obtained even if the fatty acid combination is replaced by commercially available mixtures having combinations of the same.

Example 6: Effect of the surfactant system on foam volume

In this example, a composition comprising the anionic surfactant system (Ex6) is compared to a surfactant system additionally comprising an amphoteric surfactant (Ex1 ). Table 7

^* 13.50% LAS + 3.94% SLES 2EO + 0.56% CAPB

* ^* 9% LAS + 9% SLES 2EO

The above table shows that addition of an amphoteric surfactant helps in boosting the initial foam generated by the composition according to the invention.

Example 7: Effect of the saturation of fatty acids on foam volume

In this example, the composition comprising the fatty acid combination according to the invention is compared to verify if the same initial foam volume and antifoaming effect as in Ex1 are obtained with the same unsaturated fatty acid or with a combination having one of unsaturated fatty acid (C23 and C24).

Table 8

Set *S Non- Fatt} / acid Wat Foam volume per rinse cycle, m urf loni wt% Type er Initi 1 2 3 4 5 6 act c wt% al

an Surf foa

t acta m

wt nt

% wt%

Ex1 18 0.5 0.5 C12+ 81 160 150 97 15 <10 - - C18

C3 18 0.5 0.5 C12 81 147 130 1 10 55 19 <1 -

0

C23 18 0.5 0.5 C18:1 81 1 10 1 10 70 10 - - - C24 18 0.5 0.5 C12+ 81 1 10 1 10 80 30 <10 - -

C18:1

^* 13.50% LAS + 3.94% SLES 2EO + 0.56% CAPB The above table clearly shows that use of the same unsaturated fatty acid alone or in combination with a saturated fatty acid in the composition considerably decreases the initial foam volume.