WO2016180552A1

WO2016180552A1 - Laundry detergent composition

Info

Publication number: WO2016180552A1
Application number: PCT/EP2016/054286
Authority: WO
Inventors: Stephen Norman Batchelor; Jayne Michelle Bird
Original assignee: Unilever Plc; Unilever N.V.; Conopco, Inc., D/B/A Unilever
Priority date: 2015-05-08
Filing date: 2016-03-01
Publication date: 2016-11-17
Also published as: BR112017023681B1; ZA201706682B; EP3294852A1; CN107592883A; CN107592883B; PH12017501848A1; BR112017023681A2; CL2017002802A1; AR104534A1; PH12017501848B1; EP3294852B1

Abstract

The present Invention provides and enzymatic and dispersant formulation for use in domestic laundry comprising alkyl ether carboxylic acid, protease, anionic surfactant and optional nonionic surfactant.

Description

LAUNDRY DETERGENT COMPOSITION

FIELD OF INVENTION

The present invention provides an enzymatic and dispersant formulation for use in domestic laundry.

BACKGROUND OF INVENTION

Laundry detergent formulations containing a high fraction of anionic surfactant relative to non-ionic surfactant are ubiquitous. Protease enzymes are used in laundry detergent formulations to remove protein containing stains from fabrics.

WO2013/087286 (Unilever) discloses liquids formulations containing alkyl ether carboxylic acids, betaines, anionic surfactant, non-ionic surfactant for providing softening benefits.

DE 3320340 discloses laundry detergent formulations containing and alkyl ether carboxylate with 4.5 ethoxylate units and protease enzyme. In Example A of DE 3320340 it is shown that such formulations do not stabilise the protease enzyme during storage. In Example B, D and E of DE 3320340 formulations containing alkyl ether carboxylate with 3.8 ethoxylate units and protease enzyme are stabilized for some proteases.

There is a need to increase stain removal in laundry formulations containing a high fraction of anionic surfactant relative to non-ionic surfactant.

SUMMARY OF THE INVENTION

Surprisingly the combination of a protease with specific alkyl ether carboxylic acid, provides enhanced stain removal. one aspect the present invention provides a laundry detergent composition comprising: from 5 to 50 wt% of a surfactant selected from: anionic and non-ionic surfactants, preferably from 6 to 30 wt%, more preferably 8 to 20 wt%;

wherein the weight fraction of non-ionic surfactant anionic surfactant is from 0 to 0.3, preferably 0 to 0.15, most preferably 0.05 to 0.12; from 0.5 to 20 wt%, preferably 1 .5 to 10 wt%, most preferably 2.5 to 5 wt% of an alkyl ether carboxylic acid dispersant of the following structure:

R-(OCH₂CH₂)n-OCH₂-COOH, wherein:

R is selected from saturated and mono-unsaturated C10 to C26 linear or branched alkyl chains, preferably C12 to C24 linear or branched alkyl chains, most preferably a C16 to C20 linear alkyl chain;

n is selected from 5 to 20, preferably 7 to 13, more preferably 8 to 12, most preferably 9.5 to 10.5; and, (iii) from 0.0005 to 0.2wt% of a protease enzyme, preferably from 0.002 to 0.02 wt%.

Preferably the protease is a serine protease, more preferably a subtilase type serine proteases, most preferably a subtilisin subtilase type serine protease. The wt% of anionic surfactants are calculated as the sodium salt. The wt% of the alkyl ether carboxylic acid dispersant is calculated as the COOH form. With regard to the above the alkyl ether carboxylic acid dispersants are not included as anionic surfactants.

In a further aspect the present invention provides a domestic method of treating a textile, the method comprising the steps of:

(i) treating a textile with from 1 g/L of an aqueous solution of the laundry detergent

composition as defined in any one of the preceding claims; and, (ii) allowing said aqueous laundry detergent solution to remain in contact with the textile for 10 minutes to 2 days then rinsing and drying the textile. DETAILED DESCRIPTION OF THE INVENTION Detergent format

Preferably the laundry detergent formulation is a non-phosphate built laundry detergent formulation, i.e., contains less than 1 wt% of phosphate. Preferably powder laundry detergent formulations are predominantly carbonate built. Powders, should preferably give an in use pH of 9.5-1 1.

Most preferably the laundry detergent is an aqueous liquid laundry detergent, preferably with a pH of from 7 to 9.

Protease

Protease enzymes hydrolyse bonds within peptides and proteins, in the laundry context this leads to enhanced removal of protein or peptide containing stains. Examples of suitable proteases families include aspartic proteases; cysteine proteases; glutamic proteases; aspargine peptide lyase; serine proteases and threonine proteases. Such protease families are described in the MEROPS peptidase database (http://merops.sanger.ac.uk/). Serine proteases are preferred. Subtilase type serine proteases are more preferred. The term "subtilases" refers to a sub-group of serine protease according to Siezen et al., Protein Engng. 4 (1991 ) 719-737 and Siezen et al. Protein Science 6 (1997) 501 -523. Serine proteases are a subgroup of proteases characterized by having a serine in the active site, which forms a covalent adduct with the substrate. The subtilases may be divided into 6 subdivisions, i.e. the Subtilisin family, the Thermitase family, the Proteinase K family, the Lantibiotic peptidase family, the Kexin family and the Pyrolysin family.

Examples of subtilases are those derived from Bacillus such as Bacillus lentus, B.

alkalophilus, B. subtilis, B. amyloliquefaciens, Bacillus pumilus and Bacillus gibsonii described in; US7262042 and WO09/021867, and subtilisin lentus, subtilisin Novo, subtilisin Carlsberg, Bacillus licheniformis, subtilisin BPN', subtilisin 309, subtilisin 147 and subtilisin 168 described in WO89/06279 and protease PD138 described in (WO93/18140). Other useful proteases may be those described in W092/175177, WO01/016285, WO02/026024 and WO02/016547. Examples of trypsin-like proteases are trypsin (e.g. of porcine or bovine origin) and the Fusarium protease described in WO89/06270, W094/25583 and

WO05/040372, and the chymotrypsin proteases derived from Cellumonas described in WO05/052161 and WO05/052146. Further Examples of useful proteases are the variants described in: W092/19729,

WO96/034946, WO98/201 15, WO98/201 16, WO99/01 1768, WO01/44452, WO03/006602, WO04/03186, WO04/041979, WO07/006305, W01 1/036263, W01 1/036264, especially the variants with substitutions in one or more of the following positions: 3, 4, 9, 15, 27, 36, 57, 68, 76, 87, 95, 96, 97, 98, 99, 100, 101 , 102, 103, 104, 106, 1 18, 120, 123, 128, 129, 130, 160, 167, 170, 194, 195, 199, 205, 206, 217, 218, 222, 224, 232, 235, 236, 245, 248, 252 and 274 using the BPN' numbering. More preferred the subtilase variants may comprise the mutations: S3T, V4I, S9R, A15T, K27R, ^*36D, V68A, N76D, N87S,R, ^*97E, A98S, S99G,D,A, S99AD, S101 G,M,R S103A, V104I,Y,N, S106A, G1 18V,R, H120D,N, N123S, S128L, P129Q, S130A, G160D, Y167A, R170S, A194P, G195E, V199M, V205I, L217D, N218D, M222S, A232V, K235L, Q236H, Q245R, N252K, T274A (using BPN' numbering).

Most preferably the protease is a subtilisins (EC 3.4.21 .62). Examples of subtilases are those derived from Bacillus such as Bacillus lentus, B.

alkalophilus, B. subtilis, B. amyloliquefaciens, Bacillus pumilus and Bacillus gibsonii described in; US7262042 and WO09/021867, and subtilisin lentus, subtilisin Novo, subtilisin Carlsberg, Bacillus licheniformis, subtilisin BPN', subtilisin 309, subtilisin 147 and subtilisin 168 described in WO89/06279 and protease PD138 described in (WO93/18140). Preferably the subsilisin is derived from Bacillus, preferably Bacillus lentus, B. alkalophilus, B. subtilis, B. amyloliquefaciens, Bacillus pumilus and Bacillus gibsonii as described in

US 6,312,936 Bl, US 5,679,630, US 4,760,025, US7,262,042 and WO09/021867. Most preferably the subtilisin is derived from Bacillus gibsonii or Bacillus Lentus. Suitable commercially available protease enzymes include those sold under the trade names names Alcalase®, Blaze®; DuralaseTm, DurazymTm, Relase®, Relase® Ultra, Savinase®, Savinase® Ultra, Primase®, Polarzyme®, Kannase®, Liquanase®, Liquanase® Ultra, Ovozyme®, Coronase®, Coronase® Ultra, Neutrase®, Everlase® and Esperase® all could be sold as Ultra® or Evity® (Novozymes A/S).

Those sold under the tradename Maxatase®, Maxacal®, Maxapem®, Properase®,

Purafect®, Purafect Prime®, Purafect Ox®, FN 3®, FN4®, Excellase® and Purafect OXP® by Genencor International. Those sold under the tradename Maxatase®, Maxacal®, Maxapem®, Purafect®, Purafect Prime®, PreferenzTm, Purafect MA®, Purafect Ox®, Purafect OxP®, Puramax®, Properase®, EffectenzTm, FN2®, FN3® , FN4®, Excellase®, Opticlean® and Optimase® (Danisco/DuPont), Axapem™ (Gist-Brocases N.V.),

Those available from Henkel/ Kemira, namely BLAP (sequence shown in Figure 29 of US 5,352,604 with the following mutations S99D + SIOI R + S103A + V104I + G159S, hereinafter referred to as BLAP), BLAP R (BLAP with S3T + V4I + V199M + V205I + L217D), BLAP X (BLAP with S3T + V4I + V205I) and BLAP F49 (BLAP with S3T + V4I + A194P + V199M + V205I + L217D) - all from Henkel/Kemira; and KAP (Bacillus alkalophilus subtilisin with mutations A230V + S256G + S259N) from Kao.

AlkyI Ether Carboxylic acid

In the context of the current invention alkyl ether carboxylic acid dispersants are not included as anionic surfactants. Weights of alkyl ether carboxylic acid are calculated as the protonated form, R-(OCH2CH2)n-OCH2COOH. They may be used as salt version for example sodium salt, or amine salt.

The alkyl chain may be linear or branched, preferably it is linear.

The alkyl chain may be aliphatic or contain one cis-double bond.

The alkyl chain is most preferably CH3(CH2)7CH=CH(CH₂)8-

The alkyl ether carboxylic acid is most preferably of the structure: CH₃(CH2)7CH=CH(CH2)8(OCH2CH2)ioOCH₂COOH.

Alkyl ether carboxylic acid are available from Kao (Akypo ®), Huntsman (Empicol®) and Clariant (Emulsogen ®) Surfactants

The laundry composition comprises anionic charged surfactant (which includes a mixture of the same).

Suitable anionic detergent compounds which may be used are usually water-soluble alkali metal salts of organic sulphates and sulphonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term alkyl being used to include the alkyl portion of higher alkyl radicals.

Examples of suitable synthetic anionic detergent compounds are sodium and potassium alkyl sulphates, especially those obtained by sulphating higher Cs to Cie alcohols, produced for example from tallow or coconut oil, sodium and potassium alkyl Cg to C20 benzene sulphonates, particularly sodium linear secondary alkyl C10 to C15 benzene sulphonates; and sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum.

The anionic surfactant is preferably selected from: linear alkyl benzene sulphonate; alkyl sulphates; alkyl ether sulphates; soaps; alkyl (preferably methyl) ester sulphonates, and mixtures thereof. The most preferred anionic surfactants are selected from: linear alkyl benzene sulphonate; alkyl sulphates; alkyl ether sulphates and mixtures thereof. Preferably the alkyl ether sulphate is a C12-C14 n-alkyl ether sulphate with an average of 1 to 3EO (ethoxylate) units. Sodium lauryl ether sulphate is particularly preferred (SLES). Preferably the linear alkyl benzene sulphonate is a sodium Cn to C15 alkyl benzene sulphonates. Preferably the alkyl sulphates is a linear or branched sodium C12 to Cie alkyl sulphates. Sodium dodecyl sulphate is particularly preferred, (SDS, also known as primary alkyl sulphate).

The level of anionic surfactant in the laundry composition is preferably from (i) 5 to 50 wt% negatively charged surfactant, preferably the level of negatively charged surfactant is from 6 to 30 wt%, more preferably 8 to 20 wt%.

Preferably two or more anionic surfactant are present, preferably linear alkyl benzene sulphonate together with an alkyl ether sulphate. Non-ionic surfactant may be present in the surfactant mix.

Suitable nonionic detergent compounds which may be used include, in particular, the reaction products of compounds having an aliphatic hydrophobic group and a reactive hydrogen atom, for example, aliphatic alcohols, acids or amides, especially ethylene oxide either alone or with propylene oxide. Preferred nonionic detergent compounds are the condensation products of aliphatic Cs to Cis primary or secondary linear or branched alcohols with ethylene oxide.

Preferably the alkyl ethoxylated non-ionic surfactant is a Cs to Cie primary alcohol with an average ethoxylation of 7EO to 9EO units.

Builders or Complexing Agents Builder materials may be selected from 1 ) calcium sequestrant materials, 2) precipitating materials, 3) calcium ion-exchange materials and 4) mixtures thereof.

Examples of calcium sequestrant builder materials include alkali metal polyphosphates, such as sodium tripolyphosphate and organic sequestrants, such as ethylene diamine tetra-acetic acid.

Examples of precipitating builder materials include sodium orthophosphate and sodium carbonate. Examples of calcium ion-exchange builder materials include the various types of water- insoluble crystalline or amorphous aluminosilicates, of which zeolites are the best known representatives, e.g. zeolite A, zeolite B (also known as zeolite P), zeolite C, zeolite X, zeolite Y and also the zeolite P-type as described in EP-A-0,384,070. The composition may also contain 0-65 % of a builder or complexing agent such as ethylenediaminetetraacetic acid, diethylenetriamine-pentaacetic acid, alkyl- or

alkenylsuccinic acid, nitrilotriacetic acid or the other builders mentioned below. Many builders are also bleach-stabilising agents by virtue of their ability to complex metal ions. Zeolite and carbonate (carbonate (including bicarbonate and sesquicarbonate) are preferred builders for powder detergents.

The composition may contain as builder a crystalline aluminosilicate, preferably an alkali metal aluminosilicate, more preferably a sodium aluminosilicate. This is typically present at a level of less than 15%w. Aluminosilicates are materials having the general formula: 0.8-1.5 M₂0. AI2O3. 0.8-6 Si02 where M is a monovalent cation, preferably sodium. These materials contain some bound water and are required to have a calcium ion exchange capacity of at least

50 mg CaO/g. The preferred sodium aluminosilicates contain 1.5-3.5 S1O2 units in the formula above. They can be prepared readily by reaction between sodium silicate and sodium aluminate, as amply described in the literature. The ratio of surfactants to alumuminosilicate (where present) is preferably greater than 5:2, more preferably greater than 3:1 .

Alternatively, or additionally to the aluminosilicate builders, phosphate builders may be used. In this art the term 'phosphate' embraces diphosphate, triphosphate, and phosphonate species. Other forms of builder include silicates, such as soluble silicates, metasilicates, layered silicates (e.g. SKS-6 from Hoechst).

Preferably the laundry detergent formulation is a non-phosphate built laundry detergent formulation, i.e., contains less than 1 wt% of phosphate. Preferably the powder laundry detergent formulation is carbonate built. Fluorescent Agent

The composition preferably comprises a fluorescent agent (optical brightener). Fluorescent agents are well known and many such fluorescent agents are available commercially.

Usually, these fluorescent agents are supplied and used in the form of their alkali metal salts, for example, the sodium salts. The total amount of the fluorescent agent or agents used in the composition is generally from 0.005 to 2 wt %, more preferably 0.01 to 0.1 wt %. Preferred classes of fluorescer are: Di-styryl biphenyl compounds, e.g. Tinopal (Trade Mark) CBS-X, Di-amine stilbene di-sulphonic acid compounds, e.g. Tinopal DMS pure Xtra and Blankophor (Trade Mark) HRH, and Pyrazoline compounds, e.g. Blankophor SN. Preferred fluorescers are: sodium 2 (4-styryl-3-sulfophenyl)-2H-napthol[1 ,2-d]triazole, disodium 4,4'- bis{[(4-anilino-6-(N methyl-N-2 hydroxyethyl) amino 1 ,3,5-triazin-2-yl)]amino}stilbene-2-2' disulfonate, disodium 4,4'-bis{[(4-anilino-6-morpholino-1 ,3,5-triazin-2-yl)]amino} stilbene-2-2' disulfonate, and disodium 4,4'-bis(2-sulfostyryl)biphenyl. It is preferred that the aqueous solution used in the method has a fluorescer present. When a fluorescer is present in the aqueous solution used in the method it is preferably in the range from 0.0001 g/l to 0.1 g/l, preferably 0.001 to 0.02 g/l.

Perfume

Preferably the composition comprises a perfume. The perfume is preferably in the range from 0.001 to 3 wt %, most preferably 0.1 to 1 wt %. Many suitable examples of perfumes are provided in the CTFA (Cosmetic, Toiletry and Fragrance Association) 1992 International Buyers Guide, published by CFTA Publications and OPD 1993 Chemicals Buyers Directory 80th Annual Edition, published by Schnell Publishing Co.

It is commonplace for a plurality of perfume components to be present in a formulation. In the compositions of the present invention it is envisaged that there will be four or more, preferably five or more, more preferably six or more or even seven or more different perfume components.

In perfume mixtures preferably 15 to 25 wt% are top notes. Top notes are defined by Poucher (Journal of the Society of Cosmetic Chemists 6(2):80 [1955]). Preferred top-notes are selected from citrus oils, linalool, linalyl acetate, lavender, dihydromyrcenol, rose oxide and cis-3-hexanol.

Perfume and top note may be used to cue the whiteness benefit of the invention.

It is preferred that the laundry treatment composition does not contain a peroxygen bleach, e.g., sodium percarbonate, sodium perborate, and peracid.

Polymers

The composition may comprise one or more further polymers. Examples are

carboxymethylcellulose, poly (ethylene glycol), polyvinyl alcohol), polycarboxylates such as polyacrylates, maleic/acrylic acid copolymers and lauryl methacrylate/acrylic acid copolymers. Polymers present to prevent dye deposition, for example poly(vinylpyrrolidone), poly(vinylpyridine-N-oxide), and poly(vinylimidazole), are preferably absent from the formulation.

Further Enzymes

One or more further enzymes are preferred present in a laundry composition of the invention and when practicing a method of the invention.

Preferably the level of each enzyme in the laundry composition of the invention is from 0.0001 wt% to 0.1 wt% protein.

The further enzyme is preferably selected from: amylases lipases; and, cellulases.

Any enzyme present in the composition may be stabilized using conventional stabilizing agents, e.g., a polyol such as propylene glycol or glycerol, a sugar or sugar alcohol, lactic acid, boric acid, or a boric acid derivative, e.g., an aromatic borate ester, or a phenyl boronic acid derivative such as 4-formylphenyl boronic acid, and the composition may be formulated as described in e.g. WO 92/19709 and WO 92/19708.

Shading Dyes Shading dyes are preferably present in the formulation at a level from 0.002 to 0.2 wt%.

Dyes are described in Color Chemistry Synthesis, Properties and Applications of Organic Dyes and Pigments, (H Zollinger, Wiley VCH, Zurich, 2003) and, Industrial Dyes Chemistry, Properties Applications. (K Hunger (ed), Wiley-VCH Weinheim 2003).

Shading Dyes for use in laundry detergents preferably have an extinction coefficient at the maximum absorption in the visible range (400 to 700nm) of greater than 5000 L mol^"1 cm^-1, preferably greater than 10000 L mol^"1 cm^-1. The dyes are blue or violet in colour. Preferred shading dye chromophores are azo, azine, anthraquinone, and triphenylmethane. Azo, anthraquinone, phthalocyanine and triphenylmethane dyes preferably carry a net anionic charged or are uncharged. Azine preferably carry a net anionic or cationic charge.

Blue or violet shading dyes deposit to fabric during the wash or rinse step of the washing process providing a visible hue to the fabric. In this regard the dye gives a blue or violet colour to a white cloth with a hue angle of 240 to 345, more preferably 250 to 320, most preferably 250 to 280. The white cloth used in this test is bleached non-mercerised woven cotton sheeting. Shading dyes are discussed in WO2005/003274, WO2006/032327(Unilever),

WO 2006/032397 (Unilever), WO2006/045275 (Unilever), WO06/027086 (Unilever), WO 2008/017570 (Unilever), WO 2008/141880 (Unilever), WO2009/132870 (Unilever), WO 2009/141 173 (Unilever), WO 2010/099997 (Unilever), WO 2010/102861 (Unilever), WO 2010/148624 (Unilever), WO2008/087497 (P&G), WO201 1/01 1799 (P&G),

WO2012/054820 (P&G), WO2013/142495 (P&G), and WO2013/151970 (P&G).

Mono-azo dyes preferably contain a heterocyclic ring and are most preferably thiophene dyes. The mono-azo dyes are preferably alkoxylated and are preferably uncharged or anionically charged at pH=7. Alkoxylated thiophene dyes are discussed in WO/2013/142495 and WO/2008/087497. Preferred examples of thiophene dyes are shown below:

Bis-azo dyes are preferably sulphonated bis-azo dyes. Preferred examples of sulphonated bis-azo compounds are direct violet 7, direct violet 9, direct violet 1 1 , direct violet 26, direct violet 31 , direct violet 35, direct violet 40, direct violet 41 , direct violet 51 , Direct Violet 66, direct violet 99 and alkoxylated versions thereof. Alkoxylated bis-azo dyes are discussed in WO2012/054058 and WO2010/151906. An example of an alkoxylated bis-azo dye is:

Azine dye are preferably selected from sulphonated phenazine dyes and cationic phenazine dyes. Preferred examples are acid blue 98, acid violet 50, dye with CAS-No 72749-80-5, acid blue 59, and the phenazine dye selected from:

wherein:

X₃ is selected from: -H; -F; -CH₃; -C₂H₅; -OCH₃; and, -OC₂H₅; X₄ is selected from: -H; -CH₃; -C₂H₅; -OCH₃; and, -OC₂H₅;

Y₂ is selected from: -OH; -OCH₂CH₂OH; -CH(OH)CH₂OH; -OC(0)CH₃; and, C(0)OCH₃.

The shading dye is present is present in the composition in range from 0.0001 to

0.5 wt %, preferably 0.001 to 0.1 wt%. Depending upon the nature of the shading dye there are preferred ranges depending upon the efficacy of the shading dye which is dependent on class and particular efficacy within any particular class. As stated above the shading dye is a blue or violet shading dye. A mixture of shading dyes may be used.

The shading dye is most preferably a reactive blue anthraquinone dye covalently linked to an alkoxylated polyethyleneimine. The alkoxylation is preferably selected from ethoxylation and propoxylation, most preferably propoxylation. Preferably 80 to 95 mol% of the N-H groups in the polyethylene imine are replaced with iso-propyl alcohol groups by propoxylation.

Preferably the polyethylene imine before reaction with the dye and the propoxylation has a molecular weight of 600 to 1800.

An example structure of a preferred reactive anthraquinone covalently attached to a propoxylated polyethylene imine is:

(Structure I).

Preferred reactive anthraquinone dyes are: Reactive blue 1 ; Reactive blue 2; Reactive blue 4; Reactive blue 5; Reactive blue 6; Reactive blue 12; Reactive blue 16; reactive blue 19;

Reactive blue 24 ; Reactive blue 27; Reactive blue 29; Reactive blue 36; Reactive blue 44;

Reactive blue 46 ; Reactive blue 47; reactive blue 49; Reactive blue 50; Reactive blue 53;

Reactive blue 55; Reactive blue 61 ; Reactive blue 66; Reactive blue 68; Reactive blue 69;

Reactive blue 74; Reactive blue 86; Reactive blue 93; Reactive blue 94; Reactive bluel 01 ; Reactive bluel 03; Reactive bluel 14; Reactive bluel 17; Reactive bluel 25; Reactive blue141 ; Reactive blue142; Reactive blue 145; Reactive blue 149; Reactive blue 155;

Reactive blue 164; Reactive blue 166; Reactive blue 177; Reactive blue 181 ; Reactive blue

185; Reactive blue 188; Reactive blue 189; Reactive blue 206; Reactive blue 208; Reactive blue 246; Reactive blue 247; Reactive blue 258; Reactive blue 261 ; Reactive blue 262; Reactive blue 263; and Reactive blue 172.

The dyes are listed according to Colour Index (Society of Dyers and Colourists/American Association of Textile Chemists and Colorists) classification. Experimental Example 1 An aqueous liquid laundry detergent was prepared of the following formulation:

The formulation was used to wash eight 5x5cm EMPA 1 17 stain monitor (blood/milk/ink stain on polycotton) in a tergotometer set at 200rpm. A 20 minute wash was conducted in 800ml of 26° French Hard water at 35°C, with 2.3g/L of the formulation. To simulate oily soil (12.5 g) of an SBL2004 soil strip (ex Warwick Equest) was added to the wash liquor. Once the wash had been completed the cotton monitors were rinsed once in 400ml clean water, removed dried and the colour measured on a reflectometer and expressed as the CIE L^*a^*b^* values.

Equivalent Formulations but with the addition of 8.7wt% alkyl ether carboxylic acid, wherein the alkyl group was cis-9-octadecene, were tested. The average number of ethoxy groups was varied from 2 to 10.

Experiments were repeated with and without the addition of a subtilisin serine protease ((EC no. 232-752-2) to the wash liquor (Evity® 16L ex Novozymes). The enzyme was added to give 0.009 wt% pure active protein to the formulation.

95% confidence limits are also given calculated from the standard deviation on the measurements from the 8 monitors. Without protease With protease Expected

L^* 95% L^* 95% L^* 95%

Control 49.15 0.36 50.58 0.47 - -

2EO reference 50.77 0.42 53.03 0.21 52.20 0.62

5EO 54.65 0.48 58.04 0.46 56.08 0.75

8EO 54.33 0.37 58.54 0.62 55.76 0.86

10EO 55.84 0.49 60.90 0.24 57.28 0.64

Inclusion of protease and alkyl ether carboxylic acid to the formulation increases the stain removal as seen by higher L^* values. The increase is larger for the 5EO, 8EO and largest for the 10EO. The combination of protease and alkyl ether carboxylic acid with 5EO, 8EO and 10EO gives a greater increase in stain removal than expected from combination of the effects of the single components. For 5EO/protease an L^* value of 56.08 is expected and 58.04 obtained. For 8EO/protease a value of 55.76 is expected and 58.54 obtained. The increase was greatest for 10EO/protease where a value of 57.28 is expected and 60.90 obtained.

Claims

A laundry detergent composition comprising:

(i) from 5 to 50 wt% of a surfactant selected from: anionic and non-ionic surfactants; wherein the weight fraction of non-ionic surfactant/anionic surfactant is from 0 to 0.3;

(ii) from 0.5 to 20 wt% of an alkyl ether carboxylic acid dispersant of the following structure:

R-(OCH₂CH2)n-OCH2-COOH, wherein:

R is selected from saturated and mono-unsaturated C10 to C26 linear or branched alkyl chains, and wherein n is selected from 5 to 20; and,

(iii) from 0.0005 to 0.2 wt% of a protease enzyme.

A laundry detergent composition according to claim 1 , wherein the anionic surfactant is selected from: linear alkyl benzene sulphonates; alkyl sulphates; alkyl ether sulphates; and mixtures thereof, and the non-ionic surfactant selected from: alkyl ethers with 7 to 9 ethoxy groups.

A laundry detergent composition according to claim 1 or 2, wherein the protease is a serine protease.

A laundry detergent composition according to claim 3, wherein the protease is a subtilase type serine protease.

A laundry detergent composition according to any one of claims 1 to 4, wherein n is selected from 7 to 13.

A laundry detergent composition according to any preceding claim, wherein the composition is an aqueous laundry liquid detergent. A laundry detergent composition according to any preceding claim, wherein n is selected from 9.5 to 10.5. 8. A laundry detergent composition according to any preceding claim, wherein the alkyl ether carboxylic acid dispersant is:

CH₃(CH2)7CH=CH(CH2)8(OCH2CH2)ioOCH₂COOH.

9. A laundry detergent composition according to any preceding claim, wherein the anionic and non-ionic surfactants is/are present in the range from 8 to 20 wt%. 10 A laundry detergent composition according to any preceding claim, wherein the weight fraction of non-ionic surfactant/anionic surfactant is from 0.05 to 0.12.

1 1 A laundry detergent composition according to any preceding claim, wherein the alkyl ether carboxylic acid dispersant is present in the range 1 .5 to 10 wt%. 12 A domestic method of treating a textile, the method comprising the steps of:

(i) treating a textile with from 1 g/L of an aqueous solution of the laundry detergent composition as defined in any one of the preceding claims; and, (ii) allowing said aqueous laundry detergent solution to remain in contact with the textile for 10 minutes to 2 days then rinsing and drying the textile.