Field of the invention

The present invention relates to a hard surface cleaning composition.

Background of the invention

There are several instances in day-to-day activities like e.g. washing, including laundry, dishwashing and household cleaning, which require cleaning compositions. In particular, dishwashing and household cleaning include cleaning of hard surfaces like e.g. utensils, dishes, sinks, platforms, kitchen tops, tiles, floors, cupboards and doors. Typically, hard surfaces like these are cleaned by applying a hard surface cleaning composition in neat or diluted form followed by cleaning the hard surface with a suitable means like e.g. scrub, sponge, paper, cloth, wipes and simply by using hands, and rinsing the hard surface.

Consumers often tend to use an amount of a hard surface cleaning composition, till enough foam is generated, as they usually associate efficacy of a cleaning composition with the volume of foam it generates, i.e. more foam is more efficacious. This, at times, leads to consumers using more than the required amount of a cleaning composition.

Many of the hard surface cleaning compositions available in the market are found to contain an increased amount of detergent surfactant. These increased amounts of detergent surfactant generally deliver effective cleaning. And, typically, these increased amounts of detergent surfactant are found to give rise to increased volume of foam.

These days however, there is an increasing trend to use reduced amounts of detergent surfactant in cleaning compositions from an environment point of view.

However, lowering the amount of detergent surfactant in a cleaning composition may result in ineffective cleaning. And, in many occurrences, it also leads to reduction in volume of foam which is less preferred by consumers as they associate low volume of foam with low or no efficacy of the cleaning composition. JP 05-072960 (Shiseido KK) discloses an acidic detergent composition of pH of 1.5 to 4.0 comprising anionic surfactant which has sulfonic acid or a sulfuric acid group, water- soluble polyacrylic acid or its salt and an organic acid.

Despite efforts thus far, a need for cleaning compositions that deliver effective cleaning and/or high foam volume despite using lower amounts of detergent surfactant, continues to exist.

It has been found that reducing the amount of detergent surfactant whilst maintaining at least part of the cleaning efficacy and/or foam volume is achieved by providing a composition that comprises a specific combination of anionic detergent surfactant, a polymer comprising acrylic acid and water and has pH of 5.5 or lower.

Summary of the invention

In a first aspect, the present invention provides a hard surface cleaning composition comprising:

• 5 to 60 wt% of detergent surfactant;

• 0.5 to 4 wt% of a polymer comprising acrylic acid, and;

• water;

wherein the composition is free of silicone and free of metal bleach catalyst;

wherein the composition has pH of 5.5 or lower; and

wherein at least 50% of the total amount of detergent surfactant is a combination of alkyl ether sulfate (AES) and alkyl benzene sulfonate (ABS) wherein the ratio of AES:ABS is at least 1 :1 .

In a second aspect, the present invention provides a method of cleaning a hard surface comprising the steps of:

a) applying onto a hard surface in neat or diluted form a composition according to the present invention,

b) cleaning the hard surface with a suitable means or simply with hands, and; c) rinsing the hard surface. Detailed description of the invention

Unless specified otherwise, amounts as used herein are expressed in percentage by weight based on total weight of the composition and is abbreviated as "wt%". The use of any and all examples or exemplary language e.g. "such as" provided herein is intended merely to better illuminate the invention and does not in any way limit the scope of the invention otherwise claimed.

The present invention relates to a composition that comprises a specific combination of anionic detergent surfactant, a polymer comprising acrylic acid, water and has pH of 5.5 or lower.

Detergent surfactant

There are various types of detergent surfactant, i.e. anionic, nonionic, amphoteric and cationic detergent surfactant. Detergent surfactants are one of the main ingredients that are known to provide cleaning effect.

The composition according to the present invention comprises from 5 to 60 wt%, preferably from 10 to 50 wt%, more preferably from 20 to 40 wt% and even more preferably from 30 to 35 wt% of detergent surfactant.

Out of the total amount of detergent surfactant, at least 50%, preferably at least 60%, more preferably at least 70%, even more preferably at least 80%, further more preferably at least 90% and most preferably 100%, is made up of a combination of, alkyl ether sulfate (AES) and alkyl benzene sulfonate (ABS).

For example, when the composition comprises 60 wt% detergent surfactant then at least 50% of detergent surfactant, i.e. 30 wt% of the composition in this case, is made up of AES and ABS. AES

AES is an anionic detergent surfactant of the formula Ri-(OR') _n -0-S03 ^" M ⁺ ,

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

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

Illustrative examples of AES include sodium lauryl ether sulfate (SLES), sodium myristyl ether sulfate and sodium palmityl ether sulfate. Preferred AES is SLES having 1 to 3 ethylene oxide units per molecule is preferred. SLES having 1 to 2 ethylene oxide units per molecule is the most preferred.

SLES is found in many products like e.g. soaps, shampoos, toothpaste and cleaning compositions including laundry and hard surfaces.

ABS

ABS is an anionic detergent surfactant that includes water soluble alkali metal salts of organic sulfonates having alkyi radicals typically containing from 8 to 22 carbon atoms, preferably from 8 to 18 carbon atoms, more preferably from 12 to 15 carbon atoms and may be unsaturated.

Illustrative examples of ABS include sodium salt of linear alkyi benzene sulfonate (LAS), alkyi toluene sulfonate, alkyi xylene sulfonate, alkyi phenol sulfonate, alkyi naphthalene sulfonate, ammonium diamylnaphthalene sulfonate and sodium dinonylnaphthalene sulfonate and mixtures with olefin sulfonate.

Preferred ABS is LAS having alkyi radicals containing from 12 to 14 carbon atoms. The ratio of AES:ABS

The detergent surfactant of the composition comprises at least 50% of its total amount as a combination of AES and ABS. The ratio of AES:ABS, weight by weight, is at least 1 :1 , preferably at least 2:1 , more preferably at least 3:1 , even more preferably at least 4:1 further more preferably at least 6:1 and still more preferably at least 8:1 .

When the ratio of AES:ABS is 4:1 , there are 4 parts of AES present for every 1 part of ABS. For example, when the ratio of SLES:LAS is 4:1 , there are 4 parts of SLES present for every 1 part of LAS.

It is preferred that amount of AES, is more than that of ABS. Additional detergent surfactant

The composition may further comprise one or more additional detergent surfactant, i.e. in addition to AES and ABS, as part of the detergent surfactant. These detergent surfactant can be selected from anionic, nonionic, cationic, and amphoteric types of detergent surfactant.

Illustrative examples of anionic detergent surfactant other than SLES and LAS are sodium lauryl sulfate, ammonium lauryl sulfate, soap, diethanolamine lauryl sulphate.

Illustrative examples of nonionic detergent surfactant include 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 like e.g. polyoxyethylene (4) sorbitan monolaurate, polyoxyethylene (4) sorbitan monostearate, polyoxyethylene (20) sorbitan trioleate and polyoxyethylene (20) sorbitan tristearate may also be employed as the nonionic detergent surfactant. These surfactants are commercially available from Imperial Chemical Industries under the trade name Tween™.

Preferred nonionic detergent surfactant are laureth 5, laureth 7 and laureth 9. Illustrative examples of cationic detergent surfactant are quaternary ammonium salts characterised in that the ammonium salt has the general formula: R-i R2R3R ₄ N ⁺ X ^" , wherein Ri is a C12-C18 alkyl group, each of R2, R3 and R ₄ independently is a C1-C3 alkyl group and X is an inorganic anion. Ri is preferably a Ci ₄ -Ci6 straight chain alkyl group, more preferably C16. R2-R ₄ are preferably methyl groups. The inorganic anion is preferably chosen from halide, sulphate, bisulphate or OH ^" . Thus, for the purposes of this invention, a quaternary ammonium hydroxide is considered to be a quaternary ammonium salt. More preferably the anion is a halide ion or sulphate, most preferably a chloride, bromide or sulphate. Cetyl trimethylammonium bromide is a specific example of a suitable compound.

Another type of quaternary ammonium cationic surfactant is the class of benzalkonium halides, also known as alkyldimethylbenzylammonium halides. The most common and preferred is benzalkonium chloride, also known as alkyldimethylbenzylammonium chloride (or ADBAC). A preferred class of bezalkonium chlorides is given in the formula below.

0 = 8 _» 10 _» 12, 14, 16, 18

Amphoteric detergent surfactant can be of amide, betaine, and amine oxide type, i.e. cocoamidopropyl betaine, coco amido propyl amine oxide, cocodiethanol amide and cocomonoethanol amide. Preferred amphoteric detergent surfactant is cocoamidopropyl betaine.

When used, these additional detergent surfactant can be used in an amount from 0.1 to 30 wt%, preferably from 1 to 25 wt%, more preferably from 3 to 20 wt%, even more preferably from 5 to 15 wt% and further more preferably from 8 to 13 wt%. For the avoidance of doubt, 25 wt% of additional detergent surfactant means that if the composition comprises 60 wt% detergent surfactant, the 60 wt% is made up of 35 wt% AES and ABS with the remaining 25 wt% being additional detergent surfactant.

Polymer

The composition further comprises a polymer comprising acrylic acid. The polymer can be a homopolymer or a copolymer. The composition may comprise a combination of homopolymer and a copolymer comprising acrylic acid.

We have found that the polymer in combination with detergent surfactant of the composition enhances cleaning. It also enhances foaming capacity, i.e. volume of foam, of the composition. Illustrative examples of homopolymer of acrylic acid are, hydrophobically modified acrylic based polymer emulsion commercially available under trade name Acusol™ 805s and acrylic acid homopolymer commercially available under trade name Acusol™ 445. Preferred homopolymer is acrylic acid homopolymer. Illustrative examples of copolymer comprising acrylic acid are, polymer of acrylic and methacrylic acid esters commercially available under trade name Acusol™ 845, copolymer of acrylic acid and maleic anhydride commercially available under trade name Acusol™ 497N and acrylic/maleic acid copolymer commercially available under trade name Acusol™ 505N. Preferred copolymer comprising acrylic acid is polymer of acrylic and methacrylic acid esters.

The total amount of polymer comprising acrylic acid that can be present in the composition ranges from 0.5 to 4 wt%, preferably from 0.8 to 3.5 wt%, more preferably from 1 to 3.2 wt%, even more preferably from 1 .3 to 3 wt% and further more preferably from 1 .5 to 2.8 wt%.

Water

The composition further comprises water. The amount of water ranges preferably from 40 to 94 wt%, more preferably from 50 to 90 wt%, even more preferably from 60 to 80 wt% and further more preferably from 65 to 75 wt%.

Free of silicone and free of metal catalyst bleach

The composition is free of silicone. It has been found that silicone compromises the soil tolerance of the composition. Silicone is meant to include any derivative thereof. Free of silicone is defined as not more than 1 .5 wt% silicone on total composition. Preferably the composition comprises not more than 1 wt%, more preferably not more than 0.5 wt% silicone. Even more preferably the composition is essentially free of silicone and does not comprise any silicone.

The composition is free of metal bleach catalyst. Free of metal bleach catalyst is defined as not more than 0.05 wt% metal bleach catalyst. Preferably the composition is essentially free of metal bleach catalyst and does not comprise any metal bleach catalyst.

Preferably the composition is free of any bleach as this may be considered too harsh for use as a hand dish wash composition. Bleach includes compounds containing chlorine like e.g. hypochlorite, hydrogen peroxide, ozone and the like. Free of bleach is defined as not more than 1 .5 wt% bleach on total composition. Preferably the composition comprises not more than 1 wt%, more preferably not more than 0.5 wt% bleach. Even more preferably the composition is essentially free of bleach and does not comprise any bleach. pH of the composition

A polymer as described above, in combination with detergent surfactant of the composition was found to enhance cleaning. It also enhanced the foaming capacity, i.e. volume of foam, of the composition. However, these effects were found to be pH dependent and were obtained only when the pH of the composition was 5.5 or lower. The pH of composition is 5.5 or lower, preferably lower than 5.0, more preferably lower than 4.5, even more preferably lower than 4.0 and further more preferably lower than 3.5. The pH was adjusted using conventional pH adjusters like citric acid and sodium hydroxide.

Preferably, the hard surface cleaning composition comprises:

• 5 to 60 wt% of detergent surfactant,

· 0.5 to 4 wt% of a polymer comprising acrylic acid, and;

• water;

wherein the composition has an acidic pH of 5 or lower; and

wherein at least 50% of the total amount of surfactant is a combination of AES and ABS wherein the ratio of AES:ABS is at least 1 :1 .

Product format

The composition may be used as is, i.e. neat, or it may be diluted before use. For hard surface cleaning, the composition is typically applied in its neat form directly to the surface. However, if applied in diluted form, the composition may be diluted with water in a ratio 1 :1 to 1 :10.

Optional ingredients

The composition may further comprise optional ingredients like e.g. such as colorants, preservatives, antimicrobial agents, perfumes, sequesterants and hydrotropes and polymer like e.g. POLYOX™ WSR N60K, which aid in the cleaning or sensory performance.

Method of cleaning a hard surface

In a second aspect, the present invention relates to a method of cleaning a hard surface comprising steps of:

a. applying onto a hard surface in neat or diluted form a composition according to the present invention, b. cleaning the hard surface with suitable means, and;

c. rinsing the hard surface

The composition may be applied to a hard surface by using any suitable means like e.g. by using a scrub, sponge, paper, cloth, wipes or simply by using hands for directly applying the composition. The hard surface can then be cleaned using the same suitable means.

The invention will now be illustrated by means of the following non limiting examples.

Examples

Protocols

All the compositions shown in examples 1 , 2 and 3 were prepared as described below and using amounts of SLES, LAS and polymer comprising acrylic acid as shown in the respective compositions in examples 1 , 2 and 3 below. All the compositions contained balance water to 100 wt% and contained minors like perfume color.

Preparing the compositions:

LAS acid was dissolved in water and was neutralized using sodium hydroxide. SLES was then added and the mixture was stirred continuously with overhead stirrer till SLES dissolved completely. To this, 2.7 wt% magnesium sulfate and minors like perfume and color were added. Lastly, polymer was added and the pH was adjusted to a desired value using citric acid or sodium hydroxide. Preparation of soil:

The soil used for testing is a mix of wheat flour (Aashirvaad Select Superior Sharbati Atta from ITC), sunflower oil (Sunpure, MK Agrotech Pvt Ltd), oleic acid (Loba Chemie), and stearic acid (SD fine chemicals Ltd). The typical composition of the soil is provided in Table 1. Table 1 : Composition of soil

Soil composition

Components Soil preparation (for 230 g)

( wt%)

Stearic acid 0.22 0.5

Oleic acid 0.22 0.5

Sunflower oil 8.26 19

Plain wheat flour 8.7 20

Demineralised water 82.6 190

Stearic acid and oleic acid were added to sunflower oil and heated till stearic acid melted. Water heated to 60°C was added to wheat flour and mixed thoroughly so as to avoid any lumps. The oil mixture was then added to wheat flour and mixed thoroughly. Finally remaining amount of boiling water was added to the mixture and stirred so as to break all the lumps. This mixture was then heated on a hot plate and allowed to bubble for 3 to 4 minutes. Finally, the mixture was left to cool at room temperature before using it for the studies.

Procedure for measurement of foam volume:

Initial foam volume of the composition was evaluated using Bartsch method. Stock solution containing 6.25 g/L of test solutions were prepared in 24FH water. 50 mL of the stock solution was taken in 250 mL glass cylinders and each cylinder was inverted 10 times manually through 180° using hand shaking. The total foam height was taken as the total foam volume (excluding aliquoted water). Data is reported as % foam volume with respect to control.

For control, a composition that contained 18 wt% of detergent surfactant containing SLES and LAS in 1 :1 ratio was used. The initial foam volume of the control, when measured by the method described above, was found to be 210 mL and was considered as 100%.

Soil tolerance:

Initial foam was generated as described in section above. Once the foam column had been generated, 0.5 g of soil was added to the system and the cylinder was rotated 10 times through 180° using hand shaking. The change in foam height was noted. This process was repeated till the final foam volume came down to less than 10 mL. The total amount of soil required to bring down the foam column to less than 10 mL was considered as soil tolerance of the surfactant system. Higher the soil tolerance number, better is the surfactant system, thereby, more is the efficacy of the composition. Soil tolerance data is reported as % soil tolerance with respect to control.

For control, a composition that contained 18 wt% of detergent surfactant containing SLES and LAS in 1 :1 ratio was used. Soil tolerance value of the control when measured by the soil tolerance method described above was found to be 9.5 g and was considered as 100%.

Example 1 : Effect of pH

Table 2: Effect of pH

Detergent Surfactant

Polymer

(wt%) % Soil

Ex. (Acusol 445) pH

Tolerance

SLES LAS (wt%)

1.1 10.4 2.6 0 6 79

1.2 10.4 2.6 2 6 79

1.3 10.4 2.6 2 5.5 84

1.4 10.4 2.6 2 4 100

1.5 6.5 6.5 0 6 58

1.6 6.5 6.5 2 6 58

1.7 6.5 6.5 0 4 74

1.8 6.5 6.5 2 4 84

It is seen from example 1 .3 in the table above, that at pH 5.5, soil tolerance of the composition is 84%. But at pH 4, the composition in example 1.4, showed 100% soil tolerance. Example 2: Effect of detergent surfactant ratio

Table 3: Effect of detergent surfactant ratio (at pH 4.0)

Detergent Surfactant Polymer Soil

Foam

Ex. (wt%) (Acusol 445) Tolerance

(%)

SLES LAS (wt%)

2.1 0 13 0 26 64

2.2 0 13 2 26 71

2.3 13 0 0 84 76

2.4 13 0 2 100 70

2.5 6.5 6.5 0 74 86

2.6 6.5 6.5 2 84 98

2.7 10.4 2.6 0 84 88

2.8 10.4 2.6 2 100 95

It is seen from example 2.8 in the table above, soil tolerance of the composition containing SLES and LAS in a ratio 4:1 was found to be at par with that of the control. It is also seen that the same composition, volume of foam generated was found to be 95% and was almost at par with that of the control.

Example 3: Effect of polymer levels

Table 4: Effect of polymer levels (at pH 4.0 and SLES:LAS in ratio 4:1 )

Detergent Surfactant Polymer

Soil Tolerance

Ex. (wt%) (Acusol 445)

(%)

SLES LAS (wt%)

3.1 10.4 2.6 0 84

3.2 10.4 2.6 0.25 84

3.3 10.4 2.6 0.5 89

3.4 10.4 2.6 1 100

3.5 10.4 2.6 2 100 It is seen from the table above, inclusion of 1 or 2 wt% of the polymer, soil tolerance as good as that of the control was obtained.

Thus, it can be concluded that the compositions as per the present invention, despite using reduced detergent surfactant (13 wt%) than that contained in the control (18 wt%), provided as efficacious cleaning, i.e. soil tolerance, as that provided by the control. In addition, the compositions of the present invention were also found to provide as much foaming capacity, i.e. volume of foam, as that provided by the control. Example 4: Effect of silicone on soil tolerance

Table 5: Effect of silicone on soil tolerance

Detergent Surfactant Polymer Silicone Soil

Foam

Ex. (wt%) (Acusol 445) (PDMS) Tolerance

(%)

SLES LAS (wt%) (wt%) (%)

4.1 10.4 2.6 0 0 80 92

4.2 10.4 2.6 1 0 100 97

4.3 10.4 2.6 0 4 40 60

4.4 10.4 2.6 1 4 40 50

PDMS = polvdimethylsiloxane