A laundry cleaning composition

Abstract

The present invention is in the field of laundry cleaning compositions. In particular, it relates to a stable laundry cleaning composition that provides efficient cleaning in a shorter wash cycle and less amount of water. There is still a need for an improved stable laundry cleaning composition for cleaning laundry loads with ease. It is desired that such composition provides cleaning in a shorter washing cycle with reduced amount of water. It has been found that a poly-oxyethylene sorbitan alkyl ester having specific HLB values along with a solvent mix, an anionic surfactant and an alkoxylated alkanol provides a stable laundry cleaning composition, wherein the composition provides efficient cleaning in a single wash or rinsing cycle. The composition remains stable under various storage conditions.

Description

[0001] A LAUNDRY CLEANING COMPOSITION

[0002] Field of the Invention

[0003] The present invention is in the field of laundry cleaning compositions. In particular, the present invention relates to a storage stable laundry cleaning composition that provides efficient cleaning in a shorter wash cycle and less amount of water.

[0004] Background of the Invention

[0005] Consumers spend considerable amounts of time and effort in various cleaning processes as part of their house-hold chores. These include laundering, dishwashing and cleaning household surfaces. Often such cleaning processes consume a considerable amount of water. For example, a laundering process typically involve multiple steps, namely, soaking, washing, rinsing etc., where each step requires at least a bucket / drum full of water. Furthermore, consumers often use detergents for efficient cleaning. Typically, detergents generate foam, which act as a cue for cleaning to consumers. However, it also drives consumers to use more water to wash off the foam, since they do not like the foam retaining on fabrics.

[0006] Nowadays consumers are concerned about the environment. They prefer to have products having lower impact on the environment. In laundry context, they often look for a product or a process which provides efficient cleaning with a reduced amount of water. For example, a typical laundry wash process includes steps like, soaking, washing and rinsing. It is desired to have a product that cleans a fabric in a single step thus reducing the consumption of water. This saves time and effort of consumers. Such products become more effective on fabrics having a soil or stain in a particular area rather spreading across the fabric. A shorter wash cycle or a rinsing cycle could then remove the soil / stain efficiently. It may also deliver goodies, like, perfume, hygiene actives.

[0007] In this context, WO 03 / 044149 (Unilever Pic., 2003) discloses a process of cleaning a substrate, the process comprising the steps of contacting a substrate with a composition comprising at least two liquids mutually presenting a liquid-liquid interface with an interfacial tension of at least 5 mN / m and agitating the substrate and / or composition whilst they are in mutual contact, wherein the composition and / or the substrate are also subjected to ultrasound before and / or during the agitation step. This composition does not comprise a bipolar antimicrobial particle. WO 2017 / 144260 (Unilever Pic., 2003) discloses a formulation comprising of a solvent system comprising Methyl Laurate, Di-propylene glycol n-Butyl Ether, and Octane diol. CPC clay is added to provide the antimicrobial benefit. This formulation is effective in solubilizing and removing fatty / oily stain as well as providing a hygiene benefit. However, the formulation disclosed has numerous disadvantages, including instability in hot and dry conditions; the need for a specific order of addition and mixing conditions that make the processing challenging; a high viscosity which makes the formulation hard to spray; and finally gross negative ashing or patching due to the presence of CPC clay.

[0008] WO 2020 / 048679 (Unilever Pic., 2020) discloses a fabric treatment composition comprising a solvent system comprising a glycol ether, a diol, and a fatty acid ester, alkoxylated C8- C18 anionic surfactant, alkoxylated alkanol, hydrotrope, phosphonate-based surfactant and sodium citrate.

[0009] Although various cleaning compositions are disclosed, there is still a need for an improved stable laundry cleaning composition for cleaning laundry loads with ease. It is desired that such composition provides cleaning in a shorter washing cycle with reduced amount of water and remains stable over time.

[0010] Surprisingly, it has been found that a poly-oxyethylene sorbitan alkyl ester having specific HLB values along with a solvent mix, an anionic surfactant and an alkoxylated alkanol provides a laundry cleaning composition, that provides efficient cleaning in a single wash or rinsing cycle with reduced amount of water The composition remains stable under various storage conditions,

[0011] Summary of the Invention

[0012] Accordingly, in a first aspect, the present invention provides an aqueous laundry cleaning composition comprising: i) 0.5 to 35 % by weight solvent mixture comprising:

[0013] (a) a glycol ether;

[0014] (b) a C7 to C14 vicinal diol; and

[0015] (c) a fatty acid ester of the formula RiC(=O) OR2, where R1 represents C6 to C15 alkyl group and R2 is methyl or ethyl group; ii) 0.1 to 15% by weight anionic surfactant comprising at least an alkyl ethoxylated sulphate; iii) 0.1 to 35% by weight alkoxylated alkanol; and iv) 0.1 to 10% by weight poly-oxyethylene sorbitan alkyl ester having HLB values in the range 10 to 20;

[0016] In a second aspect, the present invention provides a method for cleaning a fabric comprising the steps of:

[0017] (i) applying a composition according to the first aspect onto the fabric;

[0018] (ii) rinsing the fabric with water at least once; and

[0019] (iii) allowing the fabric to dry.

[0020] 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.

[0021] 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. Unless otherwise specified, all percentages, ratios or parts herein are on a weight basis. The term “wt%” as used herein is an abbreviation of “% by weight”.

[0022] Detailed Description of the Invention

[0023] The present invention provides an aqueous laundry cleaning composition comprising a solvent mixture, an anionic surfactant, an alkoxylated alkanol and a poly-oxyethylene sorbitan alkyl ester.

[0024] Solvent mixture The composition comprises 0.5 to 35 % by weight of a solvent mixture. Preferably, the composition comprises 1 to 30 % by weight, more preferably 2 to 25% by weight and most preferably 3 to 20% by weight of the solvent mixture.

[0025] The solvent mixture comprises a glycol ether, a C7 to C14 vicinal diol and a fatty acid ester of the formula RiC(=O) OR2, where R1 represents C6 to C15 alkyl group and R2 is methyl or ethyl group.

[0026] Glycol ether:

[0027] The solvent mixture comprises a glycol ether. Preferably the glycol ether is defined by formula: RiO(R2O)nR3; where,

[0028] R1 is a linear or branched C1 to C8 alkyl or phenyl group;

[0029] R2 is ethyl or isopropyl; n is 1 ,2,3;

[0030] R3 is hydrogen or a linear or branched 01 to 010 alkyl or phenyl group;

[0031] Glycol ether herein refers to a class of organic solvent comprising alkyl ether derivative of ethylene glycol or propylene glycol and it is defined by the formula above.

[0032] Preferably the glycol ether is selected on the basis of Hansen Solubility Parameters (HSP). HSP is a well-known computational method used to predict solubility of a material in a solvent. In this method, each material molecule is described in terms of three parameters, namely: 3d: derived from dispersion forces between molecules,

[0033] 8P: derived from dipolar intermolecular forces between molecules, and

[0034] 8h: derived from hydrogen bonds between molecules.

[0035] Different molecules are represented as points on a three-dimensional space, called Hansen space using aforesaid parameters as coordinates. Additionally, a radius Ro, known as interactive radius, is defined for each solute molecule.

[0036] To predict solubility of solute (1) in solvent (2), the HSP distance (Ra) between the two is calculated, using t formula:

[0037] Ra= [4 (8di-2+(SPi- 8p2)2+(8hi-2]1'2, and corresponding, Relative Energy Difference (RED) is calculated by, RED=Ra / R0, For a solute-solvent system, if RED value is less than 1, it means that the solute is likely to be soluble in the solvent and lower the RED value it is preferable. Whereas RED value more than 1 means that the solute may not be soluble in the solvent. Details on Hansen solubility parameters can be found in the textbooks, such as, “Hansen Solubility Parameters- A User’s Handbook”, by Dr. Charles Hansen, CRC press, Boca Raton, 1999,2007. There are software and tools commercially available for calculating HSP parameters. One of such employed here is “HSPiP” 5thedition version 5.3.04. Glycol ethers suitable for the invention have RED values in the order of 0.1 to 0.5, with respect to cooking oil as solute.

[0038] Preferably the R1 in the formula of the glycol ether is C1 to C4 alkyl group. Preferably the R3 in the formula of the glycol ether is C1 to C4 alkyl group.

[0039] Examples of glycol ether suitable for the invention include mono n- butyl ether, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol mono n-butyl ether, ethylene glycol monohexyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono propyl ether, dipropylene glycol mono n-butyl ether, and diethylene glycol butyl ether, propylene glycol mono phenyl ether and propylene glycol monomethyl ether acetate.

[0040] Glycol ether suitable for the present invention includes materials such as DOWANOL™ (trademark of The Dow Chemical Company) P and E series including both water soluble and water insoluble glycol ether or glycol ether ester, ethylene glycol mono n-butyl ether, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol mono n-butyl ether (PnB), di-propylene glycol monomethyl ether, di-propylene glycol mono propyl ether (DPnP), di-propylene glycol mono n-butyl ether (DPnB), ,and di-ethylene glycol butyl ether (DB), propylene glycol mono phenyl ether, propylene glycol monomethyl ether acetate. However, P series glycol ethers are more preferred over E-series as they are more environmentally safe.

[0041] Preferably the glycol ether is selected from di-propylene glycol n-butyl ether, di-propylene glycol dimethyl ether and di-propylene glycol methyl ether acetate, di-ethylene glycol mono hexyl ether (hexyl carbitol) and combinations thereof. Most preferred glycol ether is di-propylene glycol n- butyl ether.

[0042] The glycol ether is preferably present in a concentration of 0.1% to 20% by weight, more preferably 0.3% to 15% by weight, and most preferably 0.5 to 10 % by weight of the composition. Preferably, the glycol ether present in the composition from 2 to 66% by weight, more preferably 5 to 60% by weight, and most preferably 10 to 50 % by weight of the solvent mixture.

[0043] C7 to C14 vicinal diol

[0044] The solvent mixture comprises a C7 to C14 vicinal diol. Examples of diol suitable for the present invention include 1 ,2-heptanediol, 1 ,2-nonanediol, 1,2-decanediol, 1,2-dodecanediol, 1 ,2- tetradecanediol. Preferably, the diol is selected from 1,2 octanediol, 1,2-nonanediol, 1,2- decanediol and combinations thereof.

[0045] Preferred diol is 1 ,2 octanediol due to its superior performance in combination with glycol ether, fatty acid ester and the bipolar antimicrobial particle.

[0046] The diol is preferably present in a concentration of 0.1 to 4 % by weight, more preferably 0.2 to 3 % by weight and most preferably 0.3 to 2% by weight of the composition.

[0047] The diol preferably constitutes 3 to 30% by weight, more preferably 6 to 25% by weight, and most preferably 9 to 20 % by weight of the solvent mixture.

[0048] Fatty acid ester

[0049] The solvent mixture comprises a fatty acid ester the formula: RIC(=O)OR2wherein Ri represents C6 to C15 alkyl group and R2preferably a methyl or ethyl.

[0050] The preferred esters are those where RiCO is relatively long chain fatty acyl group, i.e. , where Ri is C7 to C18 alkyl group. In these compounds R2 is preferably a methyl group.

[0051] Most preferred fatty acid esters are methyl laurate and olefinic methyl laurate e.g., methyl dodec-9-enoate.

[0052] The fatty acid ester is preferably present in a concentration of 0.1% to 20% by weight, more preferably 0.2 to 15 % by weight and most preferably 0.3% to 10% by weight of the composition. The fatty acid ester preferably constitutes 10 to 60% by weight, more preferably 15 to 55% by weight and most preferably 20 to 50 % by weight of the solvent mixture.

[0053] Anionic surfactant

[0054] The composition comprises 0.1 to 15% by weight of anionic surfactant comprising at least an alkyl ethoxylated sulphate. Preferably, the alkyl ethoxylated sulphate has an C8 to C18 alkyl group with 1 to 30 ethoxylated unit.

[0055] The alkyl ethoxylated sulphate may have a normal or branched chain alkyl group containing lower ethoxylated groups with two or three carbon atoms. A general formula of such surfactants is

[0056] RO(C2H4O)X SO3'M+where R is a C8 to C22 alkyl group, saturated or unsaturated, M is a cation which makes the compound water-soluble, especially an alkali metal, ammonium or substituted ammonium cation, and x averages from 1 to 15. Preferably R is a C8 to C18 alkyl group, more preferably C8 to C16 alkyl group, M is sodium and x averages from 1 to 3, more preferably x is 1.

[0057] It is particularly preferred that the alkyl ethoxylated sulphate is sodium lauryl ethoxylated sulphate (SLES). It is the sodium salt of lauryl ethoxylated sulphonic acid in which the predominantly C12 (lauryl) alkyl group is ethoxylated with an average of 1 to 30 moles of ethylene oxide per mole, more preferably 1 to 15 moles of ethylene oxide per mole, still more preferably 1 to 7 moles of ethylene oxide per mole of SLES.

[0058] Other examples of suitable alkyl ethoxylated sulphate surfactants that could be used in the present invention are C12 to C15 normal or primary alkyl tri-ethoxy sulphate, sodium salt; n- decyl di-ethoxy sulphate, sodium salt; C12 primary alkyl di-ethoxy sulphate, ammonium salt; C12 primary alkyl tri-ethoxy sulphate, sodium salt; C15 primary alkyl tetra-ethoxy sulphate, sodium salt; mixed C14 to C15 normal primary alkyl mixed tri- and tetra-ethoxy sulphate, sodium salt; stearyl penta-ethoxy sulphate, sodium salt; and mixed C10 to C15 normal primary alkyl tri-ethoxy sulphate, potassium salt.

[0059] The composition preferably comprises 0.2 to 12 % by weight and more preferably 0.5 to 10 % by weight and most preferably 1 to 8 % by weight of the alkyl ethoxylated sulphate. The composition may further comprise another anionic surfactant such as, alkyl sulphonates and non-ethoxylated sulphates. Example of suitable non-ethoxylated sulphates are primary and secondary alkyl sulphates having a C10 to C18 alkyl group. Example of alkyl sulphonates suitable for the invention are linear alkyl benzene sulphonates having a C8 to C22 alkyl group, more preferably a C10 to C18 alkyl group.

[0060] Alkoxylated alkanol

[0061] The composition according to the present invention comprises 0.1 to 35 % by weight alkoxylated alkanol. Typically, alkoxylated alkanol acts as non-ionic surfactant and consider it in the composition for enhance cleaning. It is found that such compounds are produced by condensation of an organic aliphatic or alkyl aromatic hydrophobic compound with ethylene oxide.

[0062] Preferably the alkoxylated alkanols has C8 to C18 alkanol with 3 to 20 alkoxylated unit. More preferably the alkoxylated unit is ethoxylate or propoxylate. Preferred alkoxylated alkanols are those having C9 to C16 alkanol with 3 to 10 ethoxylate unit. It is preferred to use those wherein the alkoxylated alkanol is C9 to C11 or C12 to C15 alkanol with 5 to 8 or 5 to 9 ethoxy units. Preferably the alkoxylated alkanol is alkoxylated linear alcohol, and more preferably an ethoxylated linear alcohol.

[0063] Exemplary of such compounds are those in which the alkanol is of 10 to 15 carbon atoms, and which contain about 5 to 12 ethylene oxide groups per mole, e.g., Neodol™ family, Tergitol 15- S-7 etc. These are condensation products of a mixture of higher fatty alcohols averaging about 12 to 15 carbon atoms with about 9 moles of ethylene oxide. The higher alcohols are primary alkanols.

[0064] Another subclass of alkoxylated alkanol which may be used contain a precise alkyl chain length rather than an alkyl chain distribution of the alkoxylated surfactants. Typically, these are referred to as narrow range alkoxylates. Examples of these include the Neodol™-1 series of surfactants.

[0065] Examples of other useful alkoxylated alkanols include those commercially available under the trademark Plurafac™ from BASF. The Plurafac™ are the reaction products of a higher linear alcohol and a mixture of ethylene and propylene oxides, containing a mixed chain of ethylene oxide and propylene oxide, terminated by a hydroxyl group. Examples include C13 to C15 fatty alcohols condensed with 6 moles ethylene oxide and 3 moles propylene oxide, C13 to C15 fatty alcohol condensed with 7 moles propylene oxide and 4 moles ethylene oxide, C13 to C15 fatty alcohol condensed with 5 moles propylene oxide and 10 moles ethylene oxide or mixtures of any of the above. Another example includes Dobanol™ which is an ethoxylated C12 to C15 fatty alcohol with an average of 7 moles ethylene oxide per mole of fatty alcohol.

[0066] The composition comprises 0.1 to 35% by weight alkoxylated alkanol. Preferably the composition comprises 0.5 to 30% by weight, more preferably 1 to 25 % by weight and most preferably 2 to 20 % by weight of the composition.

[0067] Preferably the ratio of total amount of surfactant to solvent mixture is in the range 20: 1 to 1 : 1 by weight. More preferably the ratio is in the range 16:1 to 1:1, even more preferably 12:1 to 1 :1, yet more preferably 8:1 to 1:1 and most preferably 4:1 to 1:1 by weight.

[0068] Poly-oxyethylene sorbitan alkyl ester

[0069] The composition comprises 0.1 to 10% by weight poly-oxyethylene sorbitan ester having HLB (hydrophilic lipophilic balance) values in the range 10 to 20.

[0070] It is observed that the poly-oxyethylene sorbitan ester improves storage stability of the composition. Particularly in hot and humid condition, the composition without the polyoxyethylene sorbitan alkyl ester shows creaming on storage, whereas composition with polyoxyethylene sorbitan alkyl ester remain isotropic.

[0071] Preferably the poly-oxyethylene sorbitan alkyl ester has HLB value in the range 12 to 20, and most preferably 14 to 18. Example of such compounds include poly-oxyethylene (4) sorbitan monolaurate, poly-oxyethylene (4) sorbitan mono-stearate, poly-oxyethylene (20) sorbitan trioleate and poly-oxyethylene (20) sorbitan tri-stearate.

[0072] These compounds are also available under the trade name Tween or Triton, for example, Tween 20 (poly-oxyethylene sorbitan mono-laurate, HLB=16.7), Tween 40 (poly-oxyethylene sorbitan mono-palmitate, HLB=15.6), Tween 60 (Poly-oxyethylene sorbitan mono-stearate, HLB=14.9), Tween 65 (Poly-oxyethylene sorbitan tri-stearate, HLB=10.5), Tween 80 (Polyoxyethylene sorbitan mono-oleate, HLB=15.0), Tween 85 (Poly-oxyethylene sorbitan tri-oleate, HLB=11.0). Preferably the poly-oxyethylene sorbitan alkyl ester may be selected from poly-oxyethylene sorbitan mono-laurate, poly-oxyethylene sorbitan mono-palmitate, Poly-oxyethylene sorbitan mono-stearate and combinations thereof. Most preferred poly-oxyethylene sorbital alkyl ester is poly-oxyethylene sorbitan mono-laurate.

[0073] The poly-oxyethylene sorbitan alkyl ester may be present from 0.2 to 9 % by weight, more preferably 0.5 to 8 % by weight and most preferably 1 to 7 % by weight of the composition.

[0074] Water

[0075] The composition of the present invention is an aqueous composition comprising water. The composition is made up to 100 percent by adding water. The composition preferably comprises 40 to 97% by weight of water.

[0076] The composition may further comprise a hydrotrope. Typically hydrotropes are low molecular weight, water-soluble or water-miscible organic liquids such as C1 to C5 monohydric alcohols (such as ethanol and n- or i-propanol); C2 to C6 diols (such as mono-propylene glycol and dipropylene glycol); C3 to C9 triols (such as glycerol); polyethylene glycols having a weight average molecular weight (Mw) ranging from about 200 to 600; C1 to C3 alkanolamines such as mono-, di- and triethanolamines; and alkyl aryl sulfonates having up to 3 carbon atoms in the lower alkyl group (such as the sodium and potassium xylene, toluene, ethylbenzene and isopropyl benzene (cumene) sulfonates. A combination of these compounds may be used.

[0077] Preferably the hydrotrope is selected from 1,2 propane diol, polypropylene glycol, glycerol and combinations thereof. Most preferred hydrotrope is 1,2 propanediol.

[0078] Preferably, the amount of hydrotrope present in the composition is in the range 0.1 to 20 % by weight of the composition, more preferably in the range 1 to 16 % by weight, most preferably in the range 2 to 12 % by weight of the composition.

[0079] Preferably the composition comprises a sequestrant for improving the performance of the composition. It is believed that a sequestrant weakly binds to a calcium ion or to certain transition metal ions, like, Fe3+ which are involved in the attachment of soil to surfaces. Thereby it facilitates the removal of soil from the surfaces. Preferably, the sequestrant is selected from 1 -hydroxyl ethylidene -1,1-diphosphonic acid, 1- hydroxyl ethylidene -1,1-diphosphonic acid sodium salt, ethylidene diamine tris(methylene phosphonic acid), hydroxyl ethylidene -1,1 ,-diphosphonic acid, and sodium salts thereof.

[0080] Most preferably, the phosphonate based sequestrant is selected from 1-hydroxyl ethylidene - 1 ,1-diphosphonic acid, 1-hydroxyl ethylidene -1 ,1-diphosphonic acid sodium salt, ethylidene diamine tris(methylene phosphonic acid) and combinations thereof. The composition may further have other sequestrants such as trisodium salt of methyl glycine di-acetic acid (MGDA),

[0081] N, N-di-carboxymethyl glutamic acid tetrasodium salt (GLDA) in addition to the phosphonate based sequestrant.

[0082] Preferably the sequestrant is present in the composition from 0.5 to 10 % by weight, preferably

[0083] O.8 to 8 % by weight and most preferably 1 to 5 % by weight of the composition.

[0084] Optional ingredients

[0085] The cleaning composition may comprise additional ingredients such as polymeric emulsifiers, SRPs (soil release polymers), perfumes, preservatives, brighteners, salt to control viscosity, pH adjusters or buffers, enzymes etc. The composition of the present invention may also include optional ingredients like perfumes, preservatives, brighteners, salt to control viscosity, pH adjusters or buffers, enzymes etc.

[0086] Process for treating a fabric

[0087] In a second aspect, the invention relates to a method for treating a fabric comprising the steps in sequence of applying the composition according to the invention onto a fabric, providing required agitation as applicable followed by rinsing the fabric at least once with water; and allowing the fabric to dry. The composition may be applied by any known method such as by using wipes, spray, including spray guns, atomizers, or direct application. The method includes washing a fabric in a washing machine, wherein the fabric is treated with the composition and subsequently subjected to a rinsing cycle.

[0088] Product Format

[0089] The composition can be provided various formats, like, spray, foam and wipe. Spray and Foam can be applied to the soiled / stained area e.g., underarm, collar / cuff or can be applied to entire fabric. In a wipe format, the composition preferably be loaded on non-woven fabric. Preferably a product in wipe format can be rubbed directly on to the soil / stained areas. The viscosity of the composition preferably be less than 100 cP at 20° C at 20 S'1shear rate for it to be in foam or spray format. The composition may provide further functional benefit, like, antimicrobial benefit or may deliver a benefit agent, such as, perfume.

[0090] The invention is further illustrated by the following non-limiting examples.

[0091] Examples

[0092] Materials used for preparing various formulations are listed below: Table 1

[0093] Ex-A, B and Ex-1 to 3 were prepared following the recipe provided in table 2 as set out below:

[0094] Table 2

[0095] *Nephelometric Turbidity Unit

[0096] Ex-1 to 3 are according to the invention. Whereas Ex-A does not contain a poly-oxyethylene sorbitan ester representing a control example. Ex-B is a comparative containing polyoxyethylene lauryl ether.

[0097] For storage study, each formulation was filled in an air-tight container and stored at hot and humid condition. Hot and humid condition herein refers to 45 °C and 45 % relative humidity.

[0098] Evaluation of stain removal efficacy:

[0099] Cleaning efficacy of each formulation was evaluated in terms of stain removal index (SRI).

[0100] Standard stain monitors were used for this purpose. Stain monitors are fabrics pre-loaded with a particular type of stain. Such stain monitors are commercially available. In present case, standard single-stain monitors were procured from SUV-TUV South-East Asia Pvt Limited and used for evaluating the formulations.

[0101] SRI (stain removal index) was used to measure the efficacy of each formulation. SRI is estimated from three colour values, namely L, a, b in Cl ELAB colour space and it is defined as:

[0102] SRI = 100 where, LB, 3B, bs are colour values correspond to blank fabric, i.e. , without any stain; and Ls, as, bs are colour values correspond to stained fabric after wash. Higher the SRI value corresponds to better stain removal or better cleaning. A stained fabric, herein a single-stain monitor, was dosed with 1.35 ml of each example and was kept in contact for 5 minutes. Later the fabric was rinsed once, in a front loader washing machine at liquor to cloth ratio of 7:1 for 2 minutes in 24FH (Ca:Mg - 2:1) water. Each fabric was allowed to dry and colour values, i.e. , L, a, b in CIELAB were measured using AtrixScan F1 (Microtek).

[0103] SRI value for Ex-A and Ex-1 were estimated and summarised below:

[0104] Table 3 *type of stain on single-stain monitor.

[0105] From Table 3, it is evident that Ex-1, which is according to the present invention, records higher SRI values, i.e., provides better cleaning over Ex-A.

Claims

Claims1. An aqueous laundry cleaning composition comprising: i) 0.5 to 35 % by weight of a solvent mixture comprising:(a) a glycol ether;(b) a C7 to C14 vicinal diol; and(c) a fatty acid ester of the formula RIC(=O)OR2, where Ri represents C6 to C15 alkyl group and R2 is methyl or ethyl group; ii) 0.1 to 15% by weight of an anionic surfactant comprising at least an alkyl ethoxylated sulphate; iii) 0.1 to 35% by weight of an alkoxylated alkanol; and iv) 0.1 to 10% by weight of a poly-oxyethylene sorbitan alkyl ester having HLB values in the range 10 to 20.

2. A composition as claimed in claim 1, wherein the glycol ether is selected from dipropylene glycol n-butyl ether, di-propylene glycol dimethyl ether, di-propylene glycol methyl ether acetate, di-ethylene glycol mono hexyl ether (hexyl carbitol) and combinations thereof.

3. A composition as claimed in claim 1 or 2, wherein the diol is selected from 1 ,2 octanediol, 1,2-nonanediol, 1,2-decanediol and combinations thereof.

4. A composition as claimed in any one of claims 1 to 3, wherein the fatty acid ester is selected from methyl laurate, olefinic methyl laurate, ethyl laurate, ethyl octanoate and combinations thereof.

5. A composition as claimed in any one of claims 1 to 4 wherein the solvent mixture is a combination of di-propylene glycol n butyl ether, 1 ,2 octane diol and methyl laurate.

6. A composition as claimed in any one of claims 1 to 5, wherein the anionic surfactant comprises C8 to C18 alkyl ethoxylated sulphate having 1 to 30 ethoxylated units.

7. A composition as claimed in any one of claims 1 to 6, wherein the alkoxylated alkanol contains C6 to C18 linear or branched chain alkanol with 3 to 20 ethoxylated or propoxylated unit.

8. A composition as claimed in claim 7 wherein the alkoxylated alkanol is ethoxylated lauryl (C12) alcohol having 7 ethoxylated unit.

9. A composition as claimed in any one of claims 1 to 8 wherein the poly-oxyethylene sorbitan alkyl ester has an HLB value in the range 14 to 18.

10. A composition as claimed in claim 9 wherein the poly-oxyethylene sorbitan alkyl ester is selected from poly-oxyethylene sorbitan mono-laurate, poly-oxyethylene sorbitan monopalmitate, poly-oxyethylene sorbitan mono-stearate and combinations thereof.

11. A composition as claimed in claim 10 wherein the poly-oxyethylene sorbitan alkyl ester is poly-oxyethylene sorbitan mono-laurate.

12. A composition as claimed in any one of claims 1 to 11 comprising 0.1 to 10 % by weight of a sequestrant.

13. A composition as claimed in claim 12 wherein the sequestrant is selected from 1- hydroxyethylidene-1,1-diphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid sodium salt, ethylidene diamine tetra(methylene phosphonic acid) and combinations thereof.

14. A composition according to any one of claims 1 to 13 further comprising a hydrotrope.

15. A method for cleaning a fabric comprising the steps of:(i) applying a composition as claimed in any one of claims 1 to 14 onto the fabric;(ii) rinsing the fabric with water; and(iii) allowing the fabric to dry.

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