AU728140B2 - Detergent powder compositions with glucamide-like bleach enhancers - Google Patents

Description

WO 99/25796 PCT/EP98/07324 1 DETERGENT POWDER COMPOSITIONS WITH GLUCAMIDE-LIKE BLEACH ENHANCERS The present invention relates to detergent powder compositions, particularly those which contain a bleach component to facilitate removal of certain kinds of stains from fabrics.

Over the past few years, there has been an interest in incorporating polyhydroxy fatty acid amides into a variety of laundry products. Typically, these have been used.

for enhancement of detergency. These materials are typically surfactant compounds of formula O R 1 II I (A)

R

2

-C-N-Z

in which R' is hydrogen or a hydrocarbyl moiety of up to four carbon atoms, R 2 is a fatty-type hydrocarbyl moiety, typically having from 5 to 31 carbon atoms, and Z is an optionally alkoxylated polyhydroxy group, either of linear or sugar-type configuration.

There are many patent documents relating to the use of polyhydroxy fatty acid amides in laundry products. For example, WO-A-92 06155 describes the use of materials of formula in which Z is linear, in detergent compositions which contain a non-borate bleach.

GB-A-2 292 564 discloses the optional use of a polyhydroxy fatty acid amide in a granular detergent composition comprising surfactant, bleach and builder, wherein the surfactant builder ratio is 0.8 1 or greater. These compositions have a low pH in wash solution.

SUBSTITUTE SHEET (RULE 26) WO 99/25796 PCT/EP98/07324 2 The use of polyhydroxy fatty acid amides for stabilising aqueous liquid or paste detergent compositions is also known, for example from WO-A-93 25647. However, the latter document also states that for use in such liquid detergent applications, a preferred polyhydroxy fatty acid amide is an N-acetyl glucamide. Nevertheless, an Nacetyl glucamide is not, chemically, a polyhydroxy fatty acid amide. It actually corresponds to a compound like of formula but with the long-chain (R 2 and shortchain groups transposed and wherein Z is a glucose moiety.

EP-A-285 768 discloses the use as thickeners, in aqueous liquid detergent liquids, of a genus of materials which encompasses both the polyhydroxy fatty acid amides and N-acetyl glucamides.

Surprisingly though, it has now been found that the N-acetyl glucamides and certain analogous materials are beneficial in enhancing removal of bleach-sensitive stains when incorporated in detergent powder compositions. Thus the present invention now provides a detergent powder composition comprising an anionic and/or nonionic surfactant, a bleach and a stain-removal enhancer selected from N-(optionally substituted) acyl-N-(C 5

C

31 hydrocarbyl polyhydroxy amides, alkyl aldonamides, alkyl or alkenyl glycasuccinimides and N-(optionally substituted) aminoalkyl polyhydroxy fatty acid amides.

If the stain removal enhancer comprises an N-(optionally substituted) acyl-N-

(C

5

.C

31 hydrocarbyl polyhydroxy amide, it is preferably a compound of formula O R 3 II I (I)

R

4 -C-N-Zl wherein R 3 is a C 5

C

31 hydrocarbyl group, R 4 is hydrogen or a Ci4 alkyl group and Z' is a mono-, di- or oligo-saccharide or a polyhydroxy alkyl group optionally linked by a glycoside linkage with a mono-, di- or oligo-saccharide group.

Generally speaking, materials of formula are commercially available.

WO 99/25796 PCT/EP98/07324 3 An alkyl aldonamide is the alkyl derivative of the amide of an aldonic acid (or aldonolactone), and an aldonic acid in turn is defined as a sugar substance in which the pseudoaldehyde or pseudoketose group, generally found at the C, or C 2 position on the sugar, has been oxidized to a carboxylic acid group which upon drying cyclizes to an aldonolactone. Aldonamides may be based on compounds comprising one saccharide unit glyceramides, ribonamides, gluconamides or glucoheptonamides), two saccharide units lactobionamides, maltobionamides, melibionamides, cellobioamides, gentiobionamides or D-glucopyranosyl-(l-5)-D-arabinoamides) or they may be based on compounds comprising more than two saccharide units (e.g.

maltotrionamides or maltohexonamides). Any carbohydrate can be used as long as the sugar has a pseudoaldehyde or pseudoketose group available for oxidation to a carboxylic acid group.

If the stain removal enhancer is an alkyl aldonamide, it is preferably a compound of formula (II) O Al GlOCH2 CH C-N CH W1- CH W1--R 5

(II)

OG

n X m Xm 'p wherein: n 1-6: m =1-6; each X' is independently hydrogen or a C 1

-C

4 alkyl group; each W' is independently amine amine salt ether sulfur sulfur monoxide sulfur dioxide (SO 2 ester (SOO or OOC), amide (NACO, CONA or NCOA) group; p 0-50; G and G 2 independently represent a mono-, di-, oligo-, polysaccharide group, or a

(CH

2

CH

2 0) H or (CH 2

CHCH

3 group WO 99/25796 PCT/EP98/07324 4 q 1-50; r= 1-50; A' hydrogen, a hydroxy C 1 -C18 alkyl group, a C 1

-C,

8 straight or branched chain, a saturated or unsaturated hydrocarbon which may be unsubstituted or substituted with an aromatic, cycloaliphatic, mixed aromatic aliphatic radical or mixtures thereof; and R is a straight or branched chain, saturated or unsaturated hydrocarbon which may be unsubstituted or substituted with an aromatic, cycloaliphatic, or mixed aromatic aliphatic radical comprising from about 4 to about 28 carbon atoms.

Materials of formula (II) may be prepared as described in US-A-5 521 293.

If the stain remover is an alkyl- or alkenyl-glycasuccinimide, preferably it is a compound of formula (III): S26 I W f CH)Y 1

ZLR

CH2)c e

O

wherein A 2 is selected from the group consisting of the following structures which are attached to the succinate ring via the nitrogen atom on said structures: WO 99/25796 PTE9/72 PCT/EP98/07324 H (CHOG)f CH 2

N

GOCH

2 j H H-~CHN (CHOG)g \OGgCH H H-(CH2), (GOCH)i (GOCH)i 0OOG 0 GO(GO-CH)j OR (CE2NCCH

OG~

CH

2 N

H

(GOCH)i(GC) 0 0N

GOGO

H

(GO H)i

CH

2

N

0 N (GOCH)i

C

GOG

CH, H2GN (GOCH)i 0 OG

CH

2 0G (C j WO 99/25796 PCT/EP98/07324 6 wherein each group G is independently selected from the group consisting of hydrogen,

SO

3 M, PO 3 M, (CH 2 CH20),H, (CH 2

CHCH

3 0)bH, and mono-, di-, oligo- or polysaccharide; M is selected from hydrogen, an alkali metal, alkaline earth metal, ammonium, alkyl substituted ammonium and mono-, di-, tri-alkanolammonium groups having about 1 to about 5 carbon atoms; each W 2 is independently selected from a CH 2 group and an oxygen atom; each X 2 is independently selected from hydrogen and alkyl groups having about 1 to about 4 carbon atoms; each Y is independently selected from NR 7

+N(R

7 2 0, S, SO, SO 2 COO, OOC,

CONR

7 and NR 7 CO groups; each Z 2 is independently selected from a CH=CH and a CH 2

CH

2 group;

R

6 is a straight or branched chain saturated or unsaturated hydrocarbon which may be unsubstituted or substituted with an aromatic, cycloaliphatic or mixed aromatic radical having about 1 to about 31 carbon atoms;

R

7 is selected from hydrogen, a hydroxyl alkyl group having about 1 to about 6 carbon atoms, and straight or branched chain, saturated or unsaturated hydrocarbons which may be unsubstituted or substituted with an aromatic, cycloaliphatic or mixed aromatic aliphatic radical having about 1 to about 8 carbon atoms;

R

8 is selected from hydrogen and an alkyl, alkenyl or hydroxyalkyl group having about 1 to about 6 carbon atoms; R is selected from hydrogen and an alkyl, alkenyl or hydroxyalkyl group having about 1 to about 6 carbon atoms; and WO 99/25796 PCT/EP98/07324 7 a=0-35; b=0-35; c=1-3; d=1-5; e=0-35; f=0-8; g=1-6; h=0-2; i=0-4;j=0-3; k=0-3; and 1=0-1.

Materials of formula (III) may be prepared as described in US-A-5 541 341.

If the stain removal enhancer is an N-(optionally substituted) aminoalkyl polyhydroxy fatty acid amide, then preferably it is a compound of formula (IV): 0 Z3 R12 R1 -C-N-R11-N-R1 3

(IV)

wherein R" 0 is as hereinbefore defined for the group R 3 R" is C 1 or C 2 alkylene, R 12 and R' 3 are independently selected from hydrogen and C 1 4 alkyl, and Z 3 is as hereinbefore defined for the group Z'.

Compositions of the present invention may optionally comprise more than one stain removal enhancer selected from any of the kinds as hereinbefore defined.

Preferably, the total amount of the stain removal enhancer is from 0.1% to 10% by weight of the total composition, typically from 0.5 to 5% and especially from 2% to 3% by weight of the total composition.

Compositions according to the present invention also comprise a bleach.

Suitable bleaches include the halogen, particularly chlorine bleaches such as are provided in the form of alkalimetal hypohalites, e.g. hypochlorites. The oxygen bleaches are preferred, for example in the form of an inorganic persalt, preferably with a precursor, or else as a peroxy acid compound.

In the case of the inorganic persalt bleaches, the precursor makes the bleaching more effective at lower temperatures, i.e. in the range from ambient temperature to about 60 0 C, so that such bleach systems are commonly known as low-temperature bleach systems and are well known in the art. The inorganic persalt such as sodium perborate, both the monohydrate and the tetrahydrate, acts to release active oxygen in solution, and the precursor is usually an organic compound having one or more reactiveacyl residues, which cause the formation of peracids, the latter providing for a more WO 99/25796 PCT/EP98/07324 8 effective bleaching action at lower temperatures than the peroxybleach compound alone.

Typical examples of the suitable persalt compounds are alkalimetal perborates, both tetrahydrates and monohydrates, alkali metal percarbonates, persilicates and perphosphates, of which sodium perborate and sodium percarbonate are preferred.

Another preferred class of peroxygen compounds which can be incorporated to enhance dispensing/dispersibility in water are the anhydrous perborates described for that purpose in the EP-A-217454.

Precursors for peroxybleaches have been amply described in the literature, including in GB-A-836,988, GB-A-855,735, GB-A-907,356, GB-A-907,358, GB-A- 907,950, GB-A-1,003,310, and GB-A-1,246,339, US-A-3,332,882, US-A-4,128,494, CA-A-844,481 and ZA-A-686,344.

The exact mode of action of such precursors is not known, but it is believed that peracids are formed by reaction of the precursors with the inorganic peroxy compound, which peracids then liberate active-oxygen by decomposition.

They are generally compounds which contain N-acyl or O-acyl residues in the molecule and which exert their activating action on the peroxy compounds on contact with these in the washing liquor.

Typical examples of precursors within these groups are polyacylated alkylene diamines, such as N,N,N',N'-tetraacetylethylene diamine (TAED) and N,N,N,N'tetraacetylmethylene diamine (TAMD); acylated glycolurils, such as tetraacetylgylcoluril (TAGU); triacetylcyanurate and sodium sulphophenyl ethyl carbonic acid ester.

A particularly preferred precursor is N,N,N ,N'-tetra-acetylethylene diamine

(TAED).

WO 99/25796 PCT/EP98/07324 9 The organic peroxyacid compound bleaches are preferably those which are solid at room temperature and most preferably should have a melting point of at least 50 0

C.

Most commonly, they are the organic peroxyacids and water-soluble salts thereof having the general formula: 0

HO-O-C-R-Y

wherein R is an alkylene or substituted alkylene group containing 1 to 20 carbon atoms or an arylene group containing from 6 to 8 carbon atoms, and Y is hydrogen, halogen, alkyl, aryl or any group which provides an anionic moiety in aqueous solution.

The amount of bleach may for example be from 5% to 50% by weight of the total composition according to the present invention, for example from 10% to 30% by weight. When the bleach comprises an inorganic persalt and a precursor, and/or a peracid, the amount of the persalt may for example be from 6% to 30%, preferably from 10% to 30%, more preferably from 15% to 25%, by weight of the total composition.

The amount of any precursor and/or peracid is preferably from 0.5% to more preferably from 1% to 5% by weight of the total composition. Generally speaking though the ratio by weight of the persalt compound to the precursor is from about 15 1 to about 2 1, preferably from about 10 1 to about 3.5 1.

Compositions according to the present invention also comprise one or more anionic surfactants.

Suitable anionic surfactants are usually water-soluble alkali metal salts of organic sulphates and sulphonates having alkyl radicals containing from about 8 to 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 (C 8

-C

20 alcohols produced, for example, from tallow or coconut oil, sodium and potassium alkyl WO 99/25796 PCT/EP98/07324

(C

9

-C

2 0 benzene sulphonates, particularly sodium linear secondary alkyl (Clo-C 1 5 benzene sulphonates; sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum; sodium coconut oil fatty monoglyceride sulphates and sulphonates; sodium and potassium salts of sulphuric acid esters of higher (C 6

-C

1 8 fatty alcoholalkylene oxide, particularly ethylene oxide, reaction products; the reaction products of fatty acids such as coconut fatty acids esterified with isethionic acid and neutralised with sodium hydroxide; sodium and potassium salts of fatty acid amides of methyl taurine; alkane monosulphonates such as those derived by reacting alpha-olefins (C8- 20 with sodium bisulphite and those derived from reacting paraffins with SO 2 and Cl 2 and then hydrolyzing with a base to produce a random sulphonate; and olefin sulphonates, which term is used to describe the material made by reacting olefins, particularly CIo-

C

2 0 alpha-olefins, with S03 and then neutralising and hydrolyzing the reaction product.

The preferred anionic detergent compounds are sodium (C 11

-C

1 5 alkyl benzene sulphonates and sodium (C 16

-C

1 8 alkyl sulphates.

The amount of anionic surfactant in compositions according to the present invention is preferably no more than 30%, preferably from 1% to 20% by weight, more preferably from 5% to 15% by weight of the total composition.

Suitable nonionic surfactants include, in particular, the reaction products of compounds having a hydrophobic group and 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 alkyl (C 6

-C

1 8 primary or secondary linear or branched alcohols with ethylene oxide, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylenediamine. Other so-called nonionic detergent compounds include long chain tertiary amine oxides, long chain tertiary phosphine oxides and dialkyl sulphoxides.

WO 99/25796 PCT/EP98/07324 11 Optionally, compositions according to the present invention may also comprise one or more surfactants of another kind, selected from cationic, zwitterionic and amphoteric species, and (provided mutually compatible) mixtures thereof. For example, they may be chosen from any of the classes, sub-classes and specific materials described in 'Surface Active Agents', Vol. I, by Schwartz Perry, (Interscience 1949) and 'Surface Active Agents', Vol. II by Schwartz, Perry Berch (Interscience 1958), in the current edition of"McCutcheon's Emulsifiers Detergents" published by the McCutcheon division of Manufacturing Confectioners Company or in 'Tensid- Taschenbuch", H. Stache, 2nd Edn,., Carl Hanser Verlag, Minchen Wien, 1981.

The total amount of surfactant material in compositions according to the present invention, including the anionic surfactant, for example may be from 2% to 30% by weight of the total composition, for example from 5% to 25% and typically from to 25% by weight.

Optionally, compositions according to the present invention also comprise an alkali metal soap of a long chain mono- or dicarboxylic acid for example one having from 12 to 18 carbon atoms. Typical acids of this kind are oleic acid, ricinoleic acid and fatty acids derived from castor oil, rapeseed oil, groundnut oil, coconut oil, palm kernel oil or mixtures thereof. The sodium or potassium soaps of these acids can be used. Typical amounts of soap are from 0.5% to 5% by weight of the total composition.

It is also preferred that compositions according to the present invention include detergency builder material. The builder material is any capable of reducing the level of free calcium ions in the wash liquor and will preferably provide the composition with other beneficial properties such as the generation of an alkaline pH, the suspension of soil removed from the fabric and the dispersion of the fabric softening clay material.

Examples of phosphorus-containing inorganic detergency builders, when present, include the water-soluble salts, especially alkali metal pyrophosphates, orthophosphates, polyphosphates and phosphonates. Specific examples of inorganic WO 99/25796 PCT/EP98/07324 12 phosphate builders include sodium and potassium tripolyphosphates, phosphates and hexametaphosphates. Phosphonate sequestrant builders may also be used.

Examples of non-phosphorus-containing inorganic detergency builders, when present, include water-soluble alkali metal carbonates, bicarbonates, silicates and crystalline and amorphous aluminosilicates. Specific examples include sodium carbonate (with or without calcite seeds), potassium carbonate, sodium and potassium bicarbonates, silicates and zeolites.

Examples of organic detergency builders, when present, include the alkaline metal, ammonium and substituted ammonium polyacetates, carboxylates, polycarboxylates, polyacetyl carboxylates, carboxymethyloxysuccinates, carboxymethyloxymalonates, ethylene diamine-N,N, disuccinic acid salts, polyepoxysuccinates, oxydiacetates, triethylene tetramine hexacetic acid salts, N-alkyl imino diacetates or dipropionates, alpha sulpho-fatty acid salts, dipicolinic acid salts, oxidised polysaccharides, polyhydroxysulphonates and mixtures thereof.

Specific examples include sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylenediaminetetraacetic acid, nitrilitriacetic acid, oxydissuccinic acid, melitic acid, benzene polycarboxylic acids and citric acid, tartrate monosuccinate and tartrate disuccinate.

The amount of detergency builder is typically from 10% to 60% by weight of the total composition, preferably from 20% to 50% and more preferably from 30% to by weight of the total composition.

Apart from the ingredients already mentioned, a number of optional minor ingredients may also be present in compositions according to the present invention, for example lather boosters such as alkanolamides, particularly the monoethanolamides derived from palm kernel fatty acids and coconut fatty acids, fabric softeners such as clays, amines and amine oxides, lather depressants, inorganic salts such as sodium sulphate, and, usually present in very minor amounts, fluorescent agents, perfumes, enzymes such as proteases, amylases and lipases, germicides and colourants.

WO 99/25796 PCT/EP98/07324 13 Compositions according to the present invention may be prepared by the conventional spray-drying process or by mixing processes. In any event, components which are sensitive to any such process may be post-dosed if necessary.

The invention will now be illustrated by way of the following examples. In all examples, unless stated to the contrary, all percentages are by weight.

WO 99/25796 PCT/EP98/07324

EXAMPLES

TABLE 1 BASE FORMULATIONS A B Na PAS 9.30 Na LAS 5.88 Nonionic 7 EO 5.95 3.91 Nonionic 3 EO 3.97 2.94 Soap 1.54 0.56 Zeolite A24 31.27 STP 22.29 Na Citrate 2aq 5.19 Na-carbonate (light) 1.85 Na-disilicate 5.88 Sokalan CP5 1.06 Fluorescer 0.05 0.08 SCMC 0.88 0.21 Sokalan HP22 0.21 Remainder (11) 5.34 8.78 Sub total base powder 65.33 51.88 The following ingredients have been added (over the side) to the product: EAG fluorescer adjunct 4.00 0.8 Na carbonate 9.15 Na bicarbonate 1.00 Na percarbonate 20.50 Na perborate 4aq 18.73 TAED granules 6.50 2.06 Dequest 2047 0.45 EDDS (12) various WO 99/25796 PCT/EP98/07324

C

12

-C

1 4 primary alkyl sulphate sodium salt, anionic surfactant.

C

1 -Ci 3 alkyl benzene sulphonate sodium salt, anionic surfactant.

C

12

-C

15 fatty alcohol ethoxylated with an average of seven ethylenoxide groups per molecule, nonionic surfactant.

C

12

C

15 fatty alcohol ethoxylated with an average of three ethyleneoxide groups per molecule, nonionic surfactant.

Tinopal CBS-X optical brightener ex Ciba Sodium carboxymethyl cellulose.

Soil-release polymer ex BASF.

Silicone antifoam.

Soil-release polymer ex BASF.

Sequestering agent ex Monsanto.

(11) Moisture, salts and undefined organics.

(12) Ethylene diamino disuccinate.

To each of base formulations A and B as was added on additional by weight of a single stain removal enhancer. This was done for each of the following stain removal enhancers, respectively:- Example 1.

2.

3.

4.

6.

7.

8.

9.

Stain Removal Enhancer C12/C14 dimethylaminopropyl glucamide Undecanoyl 4-hydroxy glucamide C12/C14 N-methyl glucamide Hexadecanoyl N-methyl glucamide Coconut N-methyl glucamide N-acetyl-N-dodecyl-1-amino-l -deoxy-D-glucitol N-acetyl-N-tetradecyl-1 -amino-I -deoxy-D-glucitol N-acetyl-N-hexadecyl- 1-amino-l -deoxy-D-glucitol N-propionyl-N-dodecyl- I-amino-1 -deoxy-D-glucitol N-propionyl-N-tetradecyl-1-amino-1 -deoxy-D-glucitol WO 99/25796 PCT/EP98/07324 16 11. N-propionyl-N-hexadecyl- 1-amino-l -deoxy-D-glucitol 12. Coconut aminopropyl D-gluconamide 13. Oleyl aminopropyl D-gluconamide 14. C8/C10 oxypropyl D-gluconamide 15. Dodecyl oxypropyl D-gluconamide 16. Dodecyl N-methyl glucosylamide 17. Dodecyl lactobionamide 18. Coconut lactobionamide 19. Oleyl lactobionamide 20. Tallow (hardened) lactobionamide 21. Dodecyl oxypropyl D-lactobionamide 22. Hexadecyl maltobionamide 23. Coconut maltobionamide 24. Dodecyl oxazolidine acetamide 25. Tetradecyl oxazolidine acetamide 26. Tetradecenyl N-methyl D-glucosuccinamide 27. Decyl D-glucosuccinimide 28. Dodecenyl D-glucosuccinimide 29. Dodecenyl D-glucosuccinimide 30. Tetradecenyl D-glucosuccinimide The products were used in a concentration of 5 g/l, in a wash of 30 minutes at in a 3L beakerglass equipped with heater element and magnetic stirrer. The water was artificially hardened water of 30.4°FH (Ca Mg 4 1) with extra transition metals to imitate practical wash conditions. To ease the dissolution of the sugar-amino compounds some LES was added. This does not influence the bleach results on BC-1 test cloth.

In the case of product A the added metals were 2 ppm Fe and 2.3 ppm Zn. The bleach results on BC1 bleach test cloth ex CFT reflectance values (AR) were: WO 99/25796 PCT/EP98/07324 17 Without addition of stain removal enhancer AR 460 With 2.01% of the enhancer of Example 6 AR 460 9.9,10.4 In the case of product B the same metals were added as for A, but extra 1.1 ppm Cu and 0.12 ppm Mn. The formulations washed contained EDDS as stabiliser at 3 levels, respectively 0.20, 0.40 and 1.19% on the weight of the formulation. The experiments were performed with and without 3% of the stain removal enhancer of Example 1. The bleach results were: Without glucamide With C12/C14 glucamide 0.20% EDDS AR 460 6.5 AR 460 8.3 0.40% EDDS AR 460 6.9 AR 460 9.2 1.19% EDDS AR 460 6.5 AR 460 In the light of this disclosure, modifications of the described examples, as well as other examples, all within the scope of the present invention as defined by the appended claims will now become apparent to persons skilled in the art.

Claims (7)

1. A detergent powder composition comprising: an anionic and/or nonionic surfactant; a bleach; and a stain-removal enhancer selected from N-(optionally substituted) acyl-N-(Cs. C 3 1 hydrocarbyl polyhydroxy amides, alkyl aldonamides, alkyl or alkenyl glycasuccinimides and N-(optionally substituted) aminoalkyl polyhydroxy fatty acid amides.

2. A composition according to claim 1, wherein the amount of stain-removal enhancer is from 0.1% to 10% by weight of the total composition.

3. A composition according to claim 1 or claim 2, wherein the bleach comprises a peracid or a combination of an inorganic persalt and a bleach precursor, or both.

4. A composition according to claim 3, wherein the amount of inorganic persalt is from 6% to 30% by weight of the total composition and the amount of peracid or precursor is from 0.5% to 10% by weight of the total composition.

A composition according to claim 4, wherein the amount of inorganic persalt is from 10% to 30% by weight of the total composition.

6. A composition according to any preceding claim, wherein the amount of anionic and/or nonionic surfactant is no more than 30% by weight of the total composition.

7. A composition according to claim 6, wherein the amount of anionic and/or nonionic surfactant is from 1% to 20% by weight of the total composition.