WO2006133790A1

WO2006133790A1 - Bleaching composition

Info

Publication number: WO2006133790A1
Application number: PCT/EP2006/004889
Authority: WO
Inventors: Matthew Elliot Helton; Matthew Lloyd Parry; Christopher John Whiteoak; Marc Philip Woolfall
Original assignee: Unilever Plc; Unilever Nv; Hindustan Unilever Limited
Priority date: 2005-06-11
Filing date: 2006-05-23
Publication date: 2006-12-21
Also published as: BRPI0611890A2; CN101248167A; EP1888731A1; GB0511874D0; AR054469A1

Abstract

The present invention provides a bleaching composition comprising transition metal complex of a catechol moiety.

Description

BLEACHING COMPOSITION

FIELD OF INVENTION

This invention relates to bleaching compositions primarily for use in laundry bleaching.

BACKGROUND OF INVENTION

The use of bleaching catalysts for stain removal has been developed over recent years. The recent discovery that some catalysts are capable of bleaching effectively in the absence and presence of a peroxyl species has recently become the focus of some interest, for example: WO9965905; WO0012667; WO0012808; WO0029537, and, WO0060045.

SUMMARY OF INVENTION

The bleaching composition of the present invention also has use as an anti-dye transfer agent.

In one aspect the present invention provides a bleaching composition comprising between 0.001 to 50 wt % of a catechol moiety or transition metal complex thereof together with between 2 to 60 wt % of a surfactant, wherein the bleaching composition is substantially devoid of a peroxygen bleach or a peroxy-based or peroxyl-generating bleach system, wherein the catechol of the following formula:

or the deprotonated form thereof, wherein: Rl, R2, R3, and R4 may be independently selected from -H, - Cl, -F, -S03, -NO3, -COOH, -CH3, -C2H5, -OMe, -OEt and R2 and R3 may together form a another five or six membered aromatic ring optionally substituted with one or more groups selected from the group consisting of -H, -Cl, -F, -S03, - N03, -COOH, -CH3, -C2H5, -OMe, and -OEt.

In another aspect the present invention provides a method of treating a textile, the method comprising the steps of: (i) treating a textile with an aqueous solution of the catechol moiety, the aqueous solution having a pH of at least 7 and substantially devoid of a peroxygen bleach or a peroxy-based or peroxyl-generating bleach system, the aqueous solution comprising from 1 μM to 50 mM of a catechol transition metal complex and from 0.2 g/L to 3 g/L of a surfactant; and, (ii) rinsing and drying the textile.

The term "substantially devoid of a peroxygen bleach or a peroxy-based or peroxyl-generating bleach system" should be construed within spirit of the invention. It is preferred that the composition has as low a content of peroxyl species present as possible. It is preferred that the bleaching formulation contains less that 1 % wt/wt total concentration of peracid or hydrogen peroxide or source thereof, preferably the bleaching formulation contains less that 0.3 % wt/wt total concentration of peracid or hydrogen peroxide or source thereof, most preferably the bleaching composition is devoid of peracid or hydrogen peroxide or source thereof. In a wash environment the concentration of hydrogen peroxide or source thereof will be below 0.5 mMolar. A unit dose as used herein is a particular amount of the bleaching composition used for a type of wash. The unit dose may be in the form of a defined volume of powder, granules or tablet or unit dose detergent liquid.

DETAIL DESCRIPTION OF THE INVENTION Catechol Moiety

The catechol moiety has the core structure of 1,2- benzenediol as given immediately below.

The term catechol moiety includes the deprotonated form thereof. The core structure may in essence have any substituents about it, including conjugation with other aromatics, and still be able to co-ordinate to a transition metal centre. In basic media the catechol moiety will be present as its deprotonated analogue. Examples of extended conjugated aromatics are those of aromatic structures of naphthalene, indole, antharcene, and indene.

However, preferably the catechol moiety is of the core 1,2- benzenediol structure, that is to say that it is not in conjugation with other aromatics. Further is preferred that the catechol moiety only has two hydroxyl groups.

The catechol moiety is preferably soluble in water to the extent of at least 5mg/mL. In this regard, the presence of water solubilising groups is preferred. The water solubilizing group is most preferably a charged species: cationic or anionic. Examples of such water solubilising groups are: -S03, and -COOH. An example of a preferred catechol is Tiron® which is commercially available (4,5- dihydroxy-m-benzenedisulfonic acid disodium salt).

The catechol moiety may be used such that it forms a complex in situ during the wash. The presence of a transition metal salt in the formulation will aid complexation. However, transition metal ions, particularly iron and manganese are present in tap water and textile stains. Alternatively the catechol moiety is present as a performed complex and this is one preferred embodiment of the invention. In another preferred embodiment the catechol is uncomplexed and is used preferably in combination with sulphite and/or a transition metal complex.

When the catechol is present as the free catechol usually higher levels are present than when the transition metal complex thereof is present.

The level of the catechol moiety in a laundry detergent product will be present at 0.001 to 50 wt %, most preferably 0.1 to 25 wt %, and even more preferably from 1 to 15 wt %.

When free catechol is used in the bleaching composition the level of catechol moiety present in the wash liquor is between 0.001 to 5 g/L, most preferably between 0.01 to 3 g/L, and even more preferably from 0.1 to 1.0 g/L. In a bleaching formulation where free catechol is employed the level of transition metal salt is preferably 10 to 50 micromolar. The transition metal salt is preferably Mn(II)- (HI)-(IV)-(V) or Fe(II)-(III)-(IV)-(V) for generation of the catechol complex in situ.

The transition metal of the complex of the catechol is preferably that of Mn(II)-(III)-(IV)-(V), Fe(II)-(III)-(IV)- (V), Cu(I)-(II), Mo(IV)-(V)-(VI), W(IV)-(V)-(VI), or V(III)- (IV)-(V). Most preferably Mn(II)-(III)-(IV)-(V) or Fe(II)- (HI)-(IV)-(V) and in particular Mn(III) or Mn(IV). The level of the transition metal-catechol complex is such that the in-use level is from 1 μM to 50 mM, with preferred in- use levels for domestic laundry operations falling in the range 1 μM to 100 μM. This is preferably provided by a preformed complex in the bleaching composition. Higher levels may be desired and applied in industrial bleaching processes, such as textile and paper pulp bleaching.

The levels of active in the bleaching composition are provided by a unit dose of the laundry bleaching composition in a designated aqueous volume as directed on the package of a commercial formulation. It is also preferred that the aqueous solution has an ionic strength from 0.001 to 0.5 which is conferred by use of a unit dose of the laundry bleaching composition. It is most preferred that a unit dose of the bleaching composition confers a pH to the aqueous wash environment of at least 7, most preferably 8 and even more preferably 9.5.

Second Transition Metal Catalyst In a preferred embodiment the bleaching composition comprises a second catalyst which is other than a catechol moiety such as exemplified in WO9965905; WO0012667; WO0012808; WO0029537, and, WO0060045. The level of the second catalyst is in the same range as that for the catechol transition metal catalyst.

The second transition metal catalyst is preferably of the form:

wherein each R is independently selected from: hydrogen, hydroxyl, -NH-CO-H, -NH-CO-Cl-C4-alkyl, -NH2, -NH-C1-C4- alkyl, and Cl-C4-alkyl;

Rl and R2 are independently selected from:

Cl to ClO-alkyl, preferably Cl-C4-alkyl,

C6-C10-aryl, and, a group containing a nitrogen heteroatom capable of coordinating to a transition metal;

R3 and R4 are independently selected from hydrogen, C1-C8 alkyl, Cl-C8-alkyl-O-Cl-C8-alkyl, Cl-C8-alkyl-O-C6-C10-aryl,

Cβ-ClO-aryl, Cl-C8-hydroxyalkyl, and - (CH2) _nC (O) 0R5 wherein R5 is Cl-C4-alkyl, n is from 0 to 4, and mixtures thereof; and,

X is selected from C=O, -[C(R6)2]_y- wherein Y is from 0 to 3 each R6 is independently selected from hydrogen, hydroxyl,

Cl-C4-alkoxy and Cl-C4-alkyl. Preferred groups containing the heteroatom may be found in a heterocycloalkyl : selected from the group consisting of: pyrrolinyl; pyrrolidinyl; morpholinyl; piperidinyl; piperazinyl; hexamethylene imine; 1, 4-piperazinyl; tetrahydrothiophenyl; tetrahydrofuranyl; tetrahydropyranyl; and oxazolidinyl, wherein the heterocycloalkyl may be connected to the ligand via any atom in the ring of the selected heterocycloalkyl, a -Cl-C6-alkyl-heterocycloalkyl, wherein the heterocycloalkyl of the -Cl-C6-heterocycloalkyl is selected from the group consisting of: piperidinyl; piperidine; 1,4- piperazine, tetrahydrothiophene; tetrahydrofuran; pyrrolidine,- and tetrahydropyran, wherein the heterocycloalkyl may be connected to the -Cl-C6-alkyl via any atom in the ring of the selected heterocycloalkyl, a -Cl-C6-alkyl-heteroaryl, wherein the heteroaryl of the - Cl-C6-alkylheteroaryl is selected from the group consisting of: pyridinyl; pyrimidinyl; pyrazinyl; triazolyl; pyridazinyl; 1, 3, 5-triazinyl; quinolinyl; isoquinolinyl; quinoxalinyl; imidazolyl; pyrazolyl; benzimidazolyl; thiazolyl; oxazolidinyl; pyrrolyl; carbazolyl; indolyl; and isoindolyl, wherein the heteroaryl may be connected to the - Cl-C6-alkyl via any atom in the ring of the selected heteroaryl and the selected heteroaryl is optionally substituted by -Cl-C4-alkyl . A preferred heteroaryl substituent is Pyridine-2-ylmethyl .

Examples of most preferred groups containing the heteroatom are optionally substituted tertiary amine of the form -C2- C4-alkyl-NR7R8, in which R7 and R8 are independently selected from the group consisting of straight chain, branched or cyclo C1-C12 alkyl, benzyl, the -C2-C4-alkyl- of the -C2-C4-alkyl-NR7R8 may be substituted by 1 to 4 C1-C2- alkyl, or may form part of a C3 to C6 alkyl ring, and in which R7 and R8 may together form a saturated ring containing one or more other heteroatoms . Exemplified examples of -C2-C4-alkyl-NR7R8 are -CH2CH2-NR7R8 , -CH2CMe2- NR7R8, -CMe2CH2-NR7R8, -CMeHCH2-NR7R8, -CMeHCMeH-NR7R8 , - CH2CMeH-NR7R8, -CH2CH2CH2-NR7R8, -CH2CH2CMe2-NR7R8, - CH2CMe2CH2-NR7R8, -CH2CH2-NEt2, -CH2CH2-N (i-Pr) 2,

The second transition metal is preferably of the complex of the general formula (Al) :

[M_aL_kX_n] Y_m (Al)

in which:

M represents a metal selected from Mn(II)-(III)-(IV)-

(V), Cu(I)-(II)-(III), Fe(II)-(III)-(IV)-(V), Co(I)-(II)- (III), Ti(II)-(III)-(IV), V(II)-(III)-(IV)-(V), Mo(II)-

(IH)-(IV)-(V)-(VI) and W(IV)- (V)-(VI) , preferably selected from Fe(II)-(III)-(IV)-(V);

L represents a ligand as herein defined, or its protonated or deprotonated analogue; X represents a coordinating species selected from any mono, bi or tri charged anions and any neutral molecules able to coordinate the metal in a mono, bi or tridentate manner, preferably selected from O^2", RBO₂ ^2", RCOO^', RCONR , OH^", NO₃ ^", NO, S^2", RS^", PO₄ ^3", PO₃OR^3", H₂O, CO₃ ^2", HCO₃ ^", ROH, N(R)₃, ROO^", O₂ ^2", O₂ ^", RCN, Cl^", Br^", OCN^", SCN^", CN^", N₃ ^", F^", I^", RO^", ClO₄ ^", and CF₃SO₃ ^", and more preferably selected from O^2", RBO₂ ^2", RCOO^", OH^", NO₃ ^", S^2", RS^", PO₃ ^4", H₂O, CO₃ ^2", HCO₃ ^", ROH, N(R)₃, Cl^" , Br^", OCN^", SCN^", RCN, N₃ ^", F^", I^", RO^", ClO₄ ^", and CF₃SO₃ ^";

Y represents any non-coordinated counter ion, preferably selected from ClO₄ ^", BR₄ ^", [MX₄]^", [MX₄]^2", PF₆ ^", RCOO^", NO₃ ^", RO^", N⁺(R)₄, ROO^", O₂ ^2", O₂ ^", Cl^" , Br^", F^", I^",

CF₃SO₃ ^", S₂O₆ ^2" , OCN^", SCN^", H₂O, RBO₂ ^2", BF₄ ^" and BPh₄ ^", and more preferably selected from ClO₄ ^", BR₄ ^" , [FeCl₄] ^", PF₆ ^", RCOO^", NO₃ ^", RO^", N⁺(R)₄, Cl^" , Br^", F^", I^", CF₃SO₃ ^", S₂O₆ ^2" , OCN^", SCN^", H₂O and BF₄ ^"; a represents an integer from 1 to 10, preferably from 1 to 4; k represents an integer from 1 to 10; n represents an integer from 1 to 10, preferably from 1 to 4; m represents zero or an integer from 1 to 20, preferably from 1 to 8; and each R independently represents a group selected from hydrogen, hydroxyl, -R' and -OR', wherein R'= alkyl, alkenyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl or a carbonyl derivative group, R' being optionally substituted by one or more functional groups E, wherein E independently represents a functional group selected from -F, -Cl, -Br, -I, -OH, -OR', -NH₂, -NHR', -N (R') ₂, -N(R')₃ ⁺, -C(O)R', -OC(O)R', -COOH, -COO^" (Na⁺, K⁺), -COOR', -C(O)NH₂, -C(O)NHR', -C (O)N (R') ₂, heteroaryl, -R', -SR', -SH, -P(R')₂, -P(O) (R')₂, -P(O) (OH)₂, - P(O) (OR') 2, -NO₂, -SO₃H, -SO₃-(Na⁺, K⁺), -S(O)₂R', -NHC(O)R', and -N (R') C (0) R', wherein R' represents cycloalkyl, aryl, arylalkyl, or alkyl optionally substituted by -F, -Cl, -Br, -I, -NH₃ ⁺, -SO₃H, -SO₃-(Na⁺, K⁺), -COOH, -COO-(Na⁺, K⁺), - P(O)(OH)₂, or -P(O) (O-(Na⁺, K⁺J)₂, and preferably each R independently represents hydrogen, optionally substituted alkyl or optionally substituted aryl, more preferably hydrogen or optionally substituted phenyl, naphthyl or Ci_₄- alkyl.

The counter ions Y in formula (Al) balance the charge z on the complex formed by the ligand L, metal M and coordinating species X. Thus, if the charge z is positive, Y may be an anion such as RCOO^", BPh₄ ^", ClO₄ ^", BF₄ ^", PF₆ ^", RSO₃ ^", RSO₄ ^", SO₄ ^2" , NO₃ ^", F^", Cl^", Br^", or I^", with R being hydrogen, optionally substituted alkyl or optionally substituted aryl. If z is negative, Y may be a common cation such as an alkali metal, alkaline earth metal or (alkyl) ammonium cation.

Alkali Metal Sulphite

The alkali metal sulphite is present in the composition in the range of 0.001 to 50 wt %, most preferably 0.1 to 25 wt %, and even more preferably from 1 to 15 wt %. In the aqueous wash liquor, the level of alkali metal sulphite present in the wash liquor is between 0.001 to 5 g/L, most preferably 0.01 to 3 g/L, and even more preferably from 0.1 to 1 g/L. The alkali metal sulphite is preferably sodium sulphite . The preferred medium for use of the bleaching composition is an aqueous medium. However, organic solvents may be used, for example, methanol or ethanol .

BALANCE CARRIERS AND ADJUNCT INGREDIENTS

The bleaching composition in addition to the transition metal-catechol complex/catechol comprises the balance carriers and adjunct ingredients to 100 wt % of the composition.

These may be, for example, surfactants, builders, foam agents, anti-foam agents, solvents, fluorescers, bleaching agents, perfume and enzymes. The use and amounts of these components are such that the composition performs depending upon economics, environmental factors and use of the composition.

The composition may comprise a surfactant and optionally other conventional detergent ingredients. The composition may also comprise an enzymatic detergent composition which comprises from 0.1 to 50 wt %, based on the total detergent composition, of one or more surfactants. This surfactant system may in turn comprise 0 to 95 wt % of one or more anionic surfactants and 5 to 100 wt % of one or more nonionic surfactants. The surfactant system may additionally contain amphoteric or zwitterionic detergent compounds, but this in not normally desired owing to their relatively high cost. The enzymatic detergent composition according to the invention will generally be used as a dilution in water of about 0.05 to 2 wt%. It is preferred that the composition comprises between 2 to 60 wt % of a surfactant, most preferably 10 to 30 wt %. In general, the nonionic and anionic surfactants of the surfactant system may be chosen from the surfactants described "Surface Active Agents" Vol. 1, by Schwartz &

Perry, Interscience 1949, Vol. 2 by Schwartz, Perry & Berch, Interscience 1958, in the current edition of "McCutcheon¹ s Emulsifiers and Detergents" published by Manufacturing Confectioners Company or in "Tenside-Taschenbuch" , H. Stache, 2nd Edn., Carl Hauser Verlag, 1981.

Suitable nonionic detergent compounds which may be used include, in particular, the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example, aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide. Specific nonionic detergent compounds are Ce to C₂₂ alkyl phenol-ethylene oxide condensates, generally 5 to 25 EO, i.e. 5 to 25 units of ethylene oxide per molecule, and the condensation products of aliphatic Cs to Ciβ primary or secondary linear or branched alcohols with ethylene oxide, generally 5 to 40 EO.

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 acyl radicals. Examples of suitable synthetic anionic detergent compounds are sodium and potassium alkyl sulphates, especially those obtained by sulphating higher Ce to Cie alcohols, produced for example from tallow or coconut oil, sodium and potassium alkyl C₉ to C₂₀ benzene sulphonates, particularly sodium linear secondary alkyl Cio 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 preferred anionic detergent compounds are sodium Cu to Ci₅ alkyl benzene sulphonates and sodium C₁₂ to Cis alkyl sulphates. Also applicable are surfactants such as those described in EP-A-328 177 (Unilever) , which show resistance to salting-out, the alkyl polyglycoside surfactants described in EP-A-070 074, and alkyl monoglycosides .

Preferred surfactant systems are mixtures of anionic with nonionic detergent active materials, in particular the groups and examples of anionic and nonionic surfactants pointed out in EP-A-346 995 (Unilever) . Especially preferred is surfactant system that is a mixture of an alkali metal salt of a Ci₆ to Ci₈ primary alcohol sulphate together with a C12 to C1₅ primary alcohol 3 to 7 EO ethoxylate.

The nonionic detergent is preferably present in amounts greater than 10%, e.g. 25 to 90 wt % of the surfactant system. Anionic surfactants can be present for example in amounts in the range from about 5% to about 40 wt % of the surfactant system.

Enzymes

The bleaching compositions of the present invention preferably comprise one or more enzymes, which provide cleaning performance, fabric care and/or sanitation benefits. Reference is made to WO 03/104378 where suitable and preferred enzymes are discussed. Of the lipases Lipex® is the preferred enzyme.

FLUORESCENT AGENT

The laundry treatment 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 laundry treatment 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] trazole, disodium 4 , 4 ' -bis { [ (4-anilino-β- (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-l, 3, 5-triazin-2-yl) ] amino} stilbene-2- 2' disulfonate, and disodium 4, 4 '-bis (2- sulfoslyryl) biphenyl .

PERFUME

Preferably the bleaching composition 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.

Experimental

The synthesis of MnOOl: (H₂bispictn) [Mn₂ ¹¹¹ (Cl₄Cat) ₄ (DMF) ₂] is described by Pradyot Banerjee in Inorganic Chemistry 2004, 43(19), 5908-5918; this compound was provided by the Author.

The synthesis of FeOOl: [Fe¹¹¹ (bispicen) (Cl₄Cat) (Cl₄SQ) ]• DMF is described by Pradyot Banerjee in Inorganic Chemistry 2004, 43(19), 5908-5918; this compound was provided by the Author. The synthesis of Mn002: (Bu₄N) [Mn (Cl₄Cat) ₂ (H₂O) (EtOH) ] and

Mn003: (Bu₄N) ₂ [Mn (Cl₄Cat) ₃] is described by Tippu S. Sheriff in Inorganica Chimica Acta 2004, 357, 2494-2502; this compound was provided by the Author.

The synthesis of Mn004: (Tiron® derivative): [Na] ₅ [Mn (3, 5- (SO₃)₂Cat)₂] .10 (H₂O) (EtOH) ] is described by Tippu S. Sheriff in Inorganica Chimica Acta 2003, 348, 115-122; this compound was provided by the Author.

In the following description Cl₄Cat = 1, 2-dihydroxy-3, 4 , 5, 6- tetrachlorobenzene but one skilled in the art will appreciate that the catechol moiety when in the form of a complex will lose the two phenolic hydrogens. Measurements

After the washes, the cloths were rinsed with water and the change in colour was measured immediately after drying for 3 h at 45 °C. To express the bleaching effect a value called deltaE is used which is defined as the difference between a white cloth and that of the stained cloth after being washed. Mathematically, the definition of deltaE is:

deltaE = [ (ΔL) ² + (Δa) ² + (Δb) ² ] ^1/2

wherein ΔL is a measure of the difference in darkness between the washed and white cloth; Δa and Δb are measures for the difference in redness and yellowness respectively between both cloths. From this equation, it is clear that the lower the value of deltaE, the whiter the cloth will be. With regard to this colour measurement technique, reference is made to Commission International de l'Eclairage (CIE); Recommendation on Uniform Colour Spaces, colour difference equations, psychometric colour terms, supplement no 2 to CIE Publication, no 15, Colormetry, Bureau Central de Ia CIE, Paris 1978. The results are shown below in the tables and are listed. In the tables below the bleaching effect is expressed in the form of a stain removal index (SRI) : SRI = 100 - deltaE.

Sulphite/Tiron® on tea and wine stains at pH 10 Bleaching experiments were performed on home-made tea (PG Tips) and wine (Jacob's Creek) stains using Tiron® (4,5- dihydroxy-1, 3-benzenedisulfonic acid) and a reducing agent (Na₂SOs, sodium sulphite) . Bleaching results are given in the form of a stain removal index (SRI) where SRI = 100 - DeltaE. The higher the SRI the cleaner the cloth, SRI = 100 (white) .

Tea Stain Bleaching at pH 10

Wine Stain Bleaching at pH 10

The wash was conducted in an aqueous carbonate buffer environment at pH 10 for 60 minutes.

Sulphite/TironΘ/Mn¹¹ salt on tea stain at pH 10 Bleaching experiments were performed on a home-made tea (PG Tips) stain using Tiron® (4, 5-dihydroxy-l, 3- benzenedisulfonic acid) in the presence and absence of a reducing agent (Na₂SO₃), and a metal salt [Mn(II)Cl₂] while bubbling with and without O₂. The wash was conducted in an aqueous carbonate buffer environment at pH 10 for 30 minutes .

Tea Stain Bleaching at pH 10

Catechols and reducing agents with MnCl₂ salt on tea and wine at pH 8.5

A metal salt [Mn(II)Cl₂] and catecholate ligands were mixed in a wash experiment in the presence of reducing agents, the resulting systems were tested for bleaching activity against home-made tea (PG Tips) and red wine (Jacob's Creek) stains at pH 8.5.

Tea Stain Bleaching at pH 8.5 The wash was conducted in an aqueous EPPS (3- [4- (2-

Hydroxyethyl) -1-piperazinyl] propanesulfonic acid) buffer at pH 8.5 for 30 minutes.

Wine Stain Bleaching at pH 8.5

The wash was conducted in an aqueous EPPS buffer at pH .5 for 30 minutes.

Bleaching experiments were performed on home-made tea (PG Tips) stains using a Mn-catechol complex (MnOOl) in the presence and absence of H₂O₂. For SRI, 100 = white.

Bleaching experiments were performed on spicy turmeric (curry) stains at pH 10 with three Mn-catechol complexes, The wash was conducted in an aqueous carbonate buffer environment at pH 10 for 30 minutes.

The fact that the catechol formulation per se may be used in air or peroxyl mode, as demonstrated above, permits options for duel bleaching. A peroxyl pretreatment of a stained garment followed by addition to an aqueous medium containing catechol which is substantially devoid of peroxyl species permits the stain to be subjected to two different types of bleaching. Alternatively, after treating a stained garment in air mode a peroxyl species may be post dosed to an aqueous washing medium.

Claims

We claim :

A bleaching composition comprising between 0.001 to 50 wt % of a catechol moiety or transition metal complex thereof together with between 2 to 60 wt % of a surfactant, wherein the bleaching composition is substantially devoid of a peroxygen bleach or a peroxy- based or peroxyl-generating bleach system, wherein the catechol of the following formula:

or the deprotonated form thereof, wherein:

Rl, R2, R3, and R4 may be independently selected from - H, -Cl, -F, -S03, -N03, -COOH, -CH3, -C2H5, -OMe, -OEt and R2 and R3 may together form a another five or six membered aromatic ring optionally substituted with one or more groups selected from the group consisting of -H, -Cl, -F, -S03, -N03, -COOH, -CH3, -C2H5, -OMe, and -OEt.

2. A bleaching composition according to claim 1, wherein at least one of Rl, R2 , R3, and R4 are independently selected from S03 and Cl.

3. A bleaching composition according to claim 2, wherein the catechol is selected from the group consisting of:

4. A bleaching composition according to claim 1, wherein

the catechol is

5. A bleaching composition according to any preceding claim, wherein the catechol is a preformed complex with Mn (II), Mn (III) or Mn (IV).

6. A bleaching composition according to any preceding claim, wherein the bleaching composition comprises from 0.001 to 50 wt % of an alkali metal sulphite.

7. A bleaching composition according to any preceding claim, wherein the bleaching composition comprises a second transition metal catalyst, the second transition metal catalyst other than a catechol moiety.

8. A bleaching composition according to claim 7, wherein the second transition metal catalyst is of the form:

Rl and R2 are independently selected from: Cl to C20-alkyl, C6 to ClO-aryl, and, a group containing a nitrogen heteroatom capable of coordinating to a transition metal;

R3 and R4 are independently selected from hydrogen, Cl- C8 alkyl, Cl-C8-alkyl-O-Cl-C8-alkyl, Cl-C8-alkyl-O-C6- C10-aryl, C6-C10-aryl, Cl-C8-hydroxyalkyl, and - (CH2)_nC(O)OR5 wherein R5 is Cl-C4-alkyl, n is from 0 to 4, and mixtures thereof; and,

X is selected from C=O, -[C(R6)2_-y- wherein Y is from 0 to 3 each Rβ is independently selected from hydrogen, hydroxyl, Cl-C4-alkoxy and Cl-C4-alkyl.

A method of treating a textile, the method comprising the steps of:

(i) treating a textile with an aqueous solution of a catechol moiety as defined in any one of claims 1 to 5, the aqueous solution have a pH of at least 7 and substantially devoid of a peroxygen bleach or a peroxy- based or peroxyl-generating bleach system, the aqueous solution comprising from 1 μM to 50 mM of a catechol transition metal complex and from 0.2 g/L to 3 g/L of a surfactant; and, (ϋ) rinsing and drying the textile.

10. A method of treating a textile according to claim 9, wherein the aqueous solution has an ionic strength from 0.001 to 0.5.