GB1577140A - Liquid detergent compositions - Google Patents

Abstract

The homogeneous, liquid detergent based on water contains a) 2 to 20 per cent by weight of a synthetic detergent compound which is not a soap or a fatty acid alkylolamide, b) at least 4 per cent by weight of sodium tripolyphosphate, c) at least 2 per cent by weight of sodium orthophosphate or potassium orthophosphate, the sum of b) and c) being 6 to 35 per cent by weight, and the weight ratio of b) : c) being from 10 : 1 to 1 : 10, d) 1 to 15 per cent by weight of a hydrotropic constituent from the group consisting of alkali metal or ammonium toluene-, -xylene- or -cumenesulphonate, urea, lower aliphatic alcohols and mixtures thereof and e) 1 to 15 per cent by weight of a hydrotropic constituent from the group consisting of C8-C18-fatty acid alkylolamide, calcium soap of C10-C22-fatty acids and calcium soap of dimerised C10-C22-fatty acids in an aqeuous medium which optionally contains further customary detergent constituents.

Description

(54) LIQUID DETERGENT COMPOSITIONS (71) We, UNILEVER LIMITED, a company organised under the laws of Great Britain, of Unilever House, Blackfriars, London, EC4, England, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to liquid detergent compositions which are suitable for fabric washing, and in particular to such compositions containing phosphate detergency builders.

Aqueous built liquid detergent compositions are well known in the art. Although they offer several advantages over other forms of detergent compositions like powders, such as improved solubility and easier dosing, their formulation is very difficult, since they should be physically stable under a wide range of storage conditions, for example from about - 4CC to 37"C. Also they should have satis- factory pouring properties despite containing relatively high concentrations of detergent ingredients, especially builder salts so that ideally they have performances equivalent to the usual powdered detergent compositions.

The prior art mainly teaches the use of more water soluble ingredients, such as tetrapotassium pyrophosphate, usually with expensive stabilising agents, but even then the amount which can be used is lower than would be desired in comparison with powdered detergent compositions. Although such prior liquid formulations may provide acceptable compositions as far as their physical characteristics are concerned, their detergency and other washing properties tend to be unsatisfactory. For example, with the alkali metal pyrophosphates there are often deposits formed on the clothes, especially when the products are used at exceptionally low product concentrations, or at high temperatures. When attempts have been made to improve the detergency, then the stability and pourability have become unsatisfactory.In particular, it has not been possible to incorporate into the liquid detergent compositions sufficiently high levels of the conventional detergency builders such as sodium tripolyphosphate without causing severe problems of separation or solidification of the liquid compositions.

It has now been found that homogeneous, clear, built liquid detergent compositions cat, be obtained by using certain mixtures of sodium tripolyphosphate and sodium or potassium orthophosphate as builders, and using a hydrotrope system which comprises at least two hydrotroping agents, which will be defined hereinafter.

Insofar as the two detergency builder materials function normally in different ways, i.e. by sodium tripolyphosphate acting as a sequestrant detergency builder and the alkali metal orthophosphate functioning as a precipitant builder, it is somewhat surprising that a mixture of the materials functions so effectively. In particular, when sodium orthophosphate is used alone as a detergency builder it tends to cause inorganic deposition on the washed fabrics, which is accompanied by soil redeposition; but in the presence of the sodium tripolyphosphate the soil redeposition is significantly decreased whilst the detergency is apparently boosted.Moreover, in comparison with the use of sodium tripolyphosphate alone as detergency builder, the same amount of the mixed sodium tripolyphosphate and alkali metal orthophosphate detergency builders shows improved detergency and soil redeposition properties, especially in hard water.

There have in the past been many suggestions for using mixed phosphate detergency builders, for example mixtures of sodium pyrophosphate and sodium tripolyphosphate, in liquid compositions, particularly those adapted for hard surface cleaning. Moreover, it is well known that the condensed phosphates such as sodium tripolyphosphate tend to degrade in aqueous alkaline conditions at high temperatures, which are often met during detergent processing conditions, so as to form other phosphates; for example sodium tripolyphosphate tends to break down to give a mixture of sodium pyrophosphate and sodium orthophosphate.

However, to the Applicants' knowledge it has not been proposed hitherto to use the specific mixtures of sodium tripolyphosphate and alkali metal orthophosphate in the proportions as set out below in homogeneous fabric washing liquid detergent compositions according to the present invention. The formation of the clear liquid detergent compositions with much higher detergency builder levels than has hitherto been possible is particularly advantageous. Apart from the consumer benefits of lower viscosity and better storage properties than hetereogeneous, suspended liquid compositions, they can generally be made more easily.

The ratio of the sodium tripolyphosphate to the alkali metal orthophosphate in the detergent composition is from 10:1 to 1:10, particularly 5:1 to 1:2 parts by weight, preferably from 4:1 to 2:3, and especially from 3:1 to 1:1 parts by weight. These ratios of sodium tripolyphosphate to the alkali metal orthophosphates are chosen to give optimum detergency building and other washing properties in relation to the maximum amount of these ingredients which can be tolerated in the liquid compositions without loss of stability.

It will be appreciated that the actual amounts of sodium tripolyphosphate and alkali metal orthophosphate are chosen according to the overall phosphate detergency builder level which is desired or permitted in the liquid detergent compositions. However, it is normal to use a total amount of sodium tripolyphosphate plus alkali metal orthophosphate within the range of from 6% to 35 /O by weight of the composition, preferably from about 10% to 23%, and especially 15% to 25Vó by weight. It is also preferred that the individual amount of each of the sodium tripolyphosphate and the alkali metal orthophosphate should be at least 4% and 2% respectively, the latter preferably at least 4% by weight of the composition.

When higher levels of sodium tripolyphosphate are used, i.e. above 12% by weight of the composition, it is advantageous to use as the sodium tripolyphosphate a type of material which hydrates rapidly, as this aids its solu bilitv, particularly for use in compositions containing higher levels of sodium tripolyphosphate. Suitable types of sodium tripolyphosphate are commercially available with a high, i.e. greater than 50%, phase I content, and they may also be partially or fully prehydrated. Processing conditions, including mixing temperatures, are of course adjusted according to the type of sodium tripolyphosphate employed.

Apart from the mixed phosphate detergency builders, the liquid detergent compositions of the invention contain a detergent active compound, which may be an anionic, nonionic, amphoteric or zwitterionic detergent active compound or mixture thereof. Many suitable detergent active compounds are commercially available and are fully described in the litera ture, for example in "Surface Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch.

The preferred detergent compounds which can be used are synthetic anionic compounds.

These are usually water soluble alkali metal salts of organic sulphates and sulphonates having alkyl radicals containing from 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 primary or secondary alkyl sulphates, especially those obtained by sulphating the higher (Cs-Cis) alcohols produced by reducing the glycerides of tallow or coconut oil; sodium and potassium alkyl kC.,C2") benzene sulphonates, particularly sodium linear secondary alkyl (C,0-C15) 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 acid monoglyceride sulphates and sulphonates; sodium and potassium salts of sulphuric acid esters of higher (CqC18) fatty alcohol-alkylene 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 primary and secondary monosulphonates such as those derived by reacting alpha-olefins (C8-C2) with sodium bisulphite and those derived by reacting paraffins with SO2 and Cl2 and then hydrolysing with a base to produce a random sulphonate; and olefin sulphonates, which term is used to describe the material made by reacting olefins, particularly alpha-olefins, with SO3 and then netralising and hydrolysing the reaction product.

Although in general the sodium salts of the anionic detergent compounds are cheaper, the potassium salts may be used to advantage, particularly in compositions with high levels of other sodium salts such as sodium tripolyphosphate and sodium orthophosphate.

Of the anionic detergent compounds, alkali metal alkyl :C,,,--C,,) benzene sulphates are particularly preferred, both for ready availability and cheapness and also for their advantageous solubility properties.

If desired, nonionic detergent active compounds may be used as the sole detergent compounds, or preferably in admixture with anionic detergent compounds, especially the alkyl benzene sulphonates. Examples include the reaction products of alkylene oxides, usually ethylene oxide, with alkyl (CcC22) phenols, generally 5 to 25 EO; i.e. 5 to 25 units of ethylene oxide per molecule; the condensation products of aliphatic (C8-C1 s) primary or secondary alcohols with ethylene oxide, generally 2 to 30 EO, e.g. 6-20 EO, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylenediamine.It is also possible to use such nonionics which have been prepared by first ethoxylating and subsequently propoxylating the hydroxyl-containing organic radical, e.g. C8C16 alcohols with EO and PO. Other so-called nonionic detergent active compounds include long chain tertiary amine oxides, long chain tertiary phosphine oxides and dialkyl sulphoxides.

Mixtures of detergent active compounds, for example mixed anionic or mixed anionic and nonionic compounds may be used in the detergent compositions, particularly to impart thereto controlled low sudsing properties.

Mixtures of amine oxides and ethoxylated anionic compounds can also be beneficial.

Amounts of amphoteric or zwitterionic detergent active compounds can also be used in the liquid detergent compositions of the invention, but this is not normally desired due to their relatively high cost. If any amphoteric or zwitterionic detergent active compounds are used it is generally in small amounts in compositions based on the much more commonly used anionic and/or nonionic detergent active compounds.

The amount of the detergent active compound or compounds used is generally in the range of from 2% to 20%, preferably 5% to 15%, by weight of the compositions, depending on the desired properties. Lower levels of nonionic detergent compounds should be used within this range, as they tend to form a separate liquid phase if used at higher levels, that is over 5% by weight. The ratio of the total detergent active compounds to the total of the amount of sodium tripolyphosphate and alkali metal orthophosphate should generally be in the range of from 2:1 to 1:5, preferably 1:1 to 1:3 parts by weight.

In order to facilitate the production of the homogeneous liquid detergent compositions with relatively high levels of detergency builders present, it is preferred to use potassium rather than sodium orthophosphate.

Potassium orthophosphate can be added as such, or orthophosphoric acid may be neutralised by a potassium salt such as potassium hydroxide during production of the compositions. It should be understood that the term alkali metal orthophosphate includes the mono-, di- and tri-orthophosphates.

It is essential to have a hydrotrope system in the compositions, to reduce any tendency to separation into different liquid phases. The hydrotrope system which has been found effective for use in the homogeneous liquid detergent compositions comprises a hydrotrope, selected from the group consisting of alkalimetal or ammonium toluene-, cumene- and xylene sulphonates, urea, lower aliphatic C1- C4 monohydric alcohols such as ethanol which is commonly supplied as industrial methylated spirit (IMS), and a hydrotrope selected from the group consisting of lower (C,--C,,) fatty acid alkylolamides such as coconut ethanolamide, and readily water-soluble soaps of C10-C22 fatty acids, including such polymerised fatty acids, such as potassium coconut soap and potassium oleate, potassium soap of dimerized oleic acid and mixtures of these materials. The presence of such soaps as hydrotropes is particularly beneficial in homogeneous liquid compositions containing higher levels of sodium tripolyphosphates, i.e. over 15% by weight. The fatty acid alkylolamides also function as lather boosters and therefore should not normally be used in low sudsing compositions.

The amount of each of the hydrotropes, constituting the hydrotrope system, is normally in the range from 1% to 15%, preferably 5% to 10% by weight of the composition.

It should be noted that an excess of these hydrotropes can be deleterious just as well as too little material, for optimum liquid composition properties, but satisfactory levels can be found readily within the range described.

It is desirable to include one or more antideposition agents in the liquid detergent compositions of the invention, to decrease any tendency to form inorganic deposits on washed fabrics, especially under conditions of use as low product concentration. Examples of preferred anti-deposition agents are homoand copolyacrylates, e.g. sodium polyacrylate, the sodium salt of copolymethacrylamide/ acrylic acid and sodium poly-alpha-hydroxyacrylate, salts of copolymers of maleic anhydride with ethylene, methyl vinyl ether or styrene, especially 1:1 copolymers, optionally with partial esterification of the carboxyl groups, and the sodium salts of polymaleic acid and polyitaconic acid.Such copolymers preferably have relatively low molecular weights, e.g. in the range of 2,000 to 50,0000 The maleic anhydride copolymers can also have some stabilising properties especially when nonionic detergent compounds are used.

Other, less preferred, anti-deposition agents include phosphate esters of ethoxylated aliphatic alcohols, polyethylene glycol phosphate esters, and certain phosphonates such as sodium ethane- 1 - hydroxy - 1,1 - diphosphonate, ethylenediamine tetramethylene phosphonate and sodium 2-phosphonobutane tricarboxylate.

The most preferred anti-deposition agent is sodium polyacrylate having a MW of 2,000 to 30,000, e.g. 1S to 25,000. The amount of such anti-deposition agents is generally 0.1% to 5.0%, preferably 0.2% to 2% by weight of the compositions.

It is also possible to include in the detergent compositions of the invention minor amounts, for example up to 10% by weight, of other detergency builders, which may be either so-called precipitatnt builders or sequestrant builders. This may be of particular benefit where it is desired to increase detergency whilst using particularly low levels of the essential sodium tripolyphosphate and alkali metal orthophosphate builders, so as to achieve particularly low phosphorus contents in the detergent compositions for environmental reasons. Examples of such other detergency builders are amine carboxylates, such as sodium nitrilotriacetate.However, it is desirable to have no other phosphate detergency builders present other than the sodium tripolyphosphate and alkali metal orthoprosphate, and in particular it is desirable to exclude pyrophosphates from the compositions as they tend to increase inorganic deposition and soil redeposition. Some pyrophosphate may be present for example as an impurity in the sodium tripolyphosphate, or it may be produced by hydrolysis of the sodium tripolyphosphate during detergent processing particularly under alkaline conditions at elevated temperatures, so low levels of sodium pyrophosphate may be unavoidable, but it is preferred to have no more than 5%, especially less than 2% by weight of pyrophosphate present in the compositions.

The liquid detergent compositions of the invention can contain any of the conventional additives in the amounts in which such additives are normally employed in liquid fabric washing detergent compositions. Examples of these additives include lather depressants, anti-redeposition agents such as carboxymehtylcellulose (CMC), alkaline salts such as alkali metal carbonate or alkali metal hyldroxides, and, usually present in very minor amounts, fluorescent agents, perfumes, enzymes such as proteases and amylases, germicides and colourants. When CMC is used it has been found advantageous to incorporate also a stabilising agent for this material, e.g. a hydrogenated castor oil (castor wax), carnauba wax, beeswax, etc.

The balance of the compositions is water, which is usually present to the extent of 40%, to 75% by weight, preferably 45% to 65% by weight.

To ensure effective detergency the liquid detergent compositions should be alkaline, and it is preferred that they should provide a pH within the range of 9 to 12, preferably pH 9.5 to 11 when used in aqueous solution of the composition at the recommended concentration. To meet this requirement, the undiluted liquid composition should also be of high pil, for example pH 12 to 13, preferably about pH 12.5. It should be noted that an excessively high .pH, e.g. over pH 13 is less desirable for domestic safety. The ingredients in any such highly alkaline detergent composition should of course be chosen for alkaline stability, especially for pH-sensitive materials such as enzymes, and a particularly suitable proteolytic enzyme in this respect is available under the trade name "Esperase".

It is desirable to include in the compositions an alkaline buffer, for example alkali metal carbonate, to maintain the pH of at least 9 during use, particularly under conditions of use, for example in hard water or at low product concentrations, when the alkali metal orthophosphate is precipitated in the form of its calcium salt and cannot itself then act as an alkaline buffer. Alkali metal silicates, for example sodium ortho-, meta- or preferably neutral or alkaline silicates, which are commonly used as alkaline buffers are more difficult to incorporate in the homogeneous liquid compositions, especially at higher sodium tripolyphosphate levels. An alkali metal hydroxide, may alternatively or additionally be used to provide an initially high pH.

The liquid detergent compositions can be made easily by adding the ingredients to water in conventional detergent processing equipment. It is preferred for higher levels of phosphate builders to heat the water first, e.g. to 60"C to 80"C, and then to add the inorganic detergency builders, followed by the detergent active compound or compounds and then other inorganic materials. Alternatively, if desired, the heat of reaction between acidic and alkaline ingredients may be used to raise the temperature and facilitate mixing of the ingredients.

The resultant compositions have viscosities in the range from 20 to 2,000, especially 50 to 1,000 centipoise, as measured at room temperature in a Brookfield viscometer (Spindle No. 3, 30 rpm).

The invention is illustrated by the following Examples in which parts and percentages are by weight except where otherwise indicated.

Examples I to X.

A series of stable homogeneous liquid detergent compositions were made to the following formulations: Percentages Ingredient Ex 1 Ex 2 Ex 3 Ex 4 Ex 5 Ex 6 Ex 7 Ex 8 Ex 9 Ex 10 Sodium alkyl benzene sulphonate1 6 6 6 6 6 6 7.5 7.5 6 6 Tallow fatty amide - 11 EO 2 2 2 2 2 - - - 2 2 Sodium tripolyphosphate 10 10 10 10 10 10 10 10 13 15 Potassium orthophosphate 10 10 10 10 10 10 7.5 7.5 6 7.5 Coconut fatty acid2 - - 2 5 5 5 11 11 - Potassium hydroxide 2 2 3 4 2 2 4 4 1 1 Dimerised oleic acid3 2 2 2 2 - - - - 5 5 Sodium xylene sulphonate 5 5 5 5 5 5 3 5 5 5 Ethanol - 2 2 2 2 5 2.0 - - Water 63 61 58 54 58 60 55 55 62 58.5 1 In Examples 1 to 8 the alkyl benzene sulphonate had a (C11-C15) alkyl group and in Examples 9 and 10 an alkyl (C11-C12) benzene sulphonate was used.

2 Neutralised by some of the KOH to form potassium coconut soap in the composition.

3 Obtained as EMPOL, used for lather control, neutralised by the KOH in the composition.

All these formulations had good detergency properties due to the relatively high detergency building properties of the sodium tripolyphosphate and potassium orthophosphate.

Example XI.

A clear, homogeneous low-sudsing liquid detergent composition was made to the following formulation: Ingredient Sodium alkyl (C,1-C22) benzene sulphonate 6.0 Tallow fatty amide - 11 EO 2.0 Dimerised oleic acid 5.0 Sodium tripolyphosphate 10.0 Potassium crthophosphate 6.0 Sodium xylene sulphonate 5.0 Potassium hydroxide 1.0 Potassium carbonate 5.0 Water 60.0 This liquid composition was readily pourable and was stable on storage down to about - 10"C. Replacement of the potassium carbonate by sodium carbonate also gave a clear stable liquid but of higher viscosity. In both cases the alkaline buffering effect of the carbonate improved the detergent properties of the composition.

Example XII.

A homogeneous clear built liquid composition was prepared to the following formulation: Ingredient C/c Potassium alkyl benzene sulphonate 7.50 Alkyl (C16-C18) - 25 EO 1.45 Alkyl (C13-C,3) - 11 EO 0.80 Dimerised oleic acid 5.50 Sodium tripolyphosphate 13.00 Potassium orthophosphatel 7.70 Sodium xylene sulphonate 6.10 Fluorescent agent 0.15 Water 57.80 Made by reaction between orthophosphoric acid and potassium hydroxide during pro duction of the composition.

This composition had a low viscosity and was found to be stable down to - 4 C.

Example XI II.

A clear isotropic high-sudsing built liquid detergent composition was prepared to the following formulation: Ingredient Potassium alkyl benzene sulphonate2 8.0 Alkanol (C-C23) - 8 EO 2.0 Potassium hydroxide 4.5 Sodium tripolyphosphate 16.5 Potassium orthophosphate2 5.0 Coconut fatty diethanolamide 2.0 Potassium coconut soap' 1.0 Sodium xylene sulphonate/toluene sulphonate (4:1) 6.0 Water 55.9 1 Calculated in acid form.

2 Formed from dipotassium hydrogen ortho phosphate by reaction with the potassium hydroxide.

This product was found to have good stability ( - 5 C to 520C) and a low viscosity of about 100 to 200 centipoise at room temperature (Brookfield Spindle No. 3, 30 rpm) at pH 12.5. Replacement of the nonionic detergent compound with other similar materials, e.g. alkanol (C1-C,,) - 6 EO, alkanol (C12-C15) 7 - EO or alkanol (C,2 -C13) - 3 EO was found to be equally satisfactory.

Example XIV.

A homogeneous clear built liquid composition was prepared to the following formulation: Ingredient Potassium alkylbenzene sulphonate (C11-C,,) (as acid) 6 C,2-C13 linear primary alcohol, condensed with 7 moles of ethylene/ propylene oxide (mole ratio 88:12) 2.5 Oleic acid 5.0 Sodium tripolyphosphate 16.5 Potassium orthophosphate 6.0 KOH 4.0 Sodium toluene sulphonate 6.0 CMC (sodium salt) 0.25 Castor wax 0.25 Fluorescer, dyes, perfume, etc. 0.3 Water 53.2 The viscosity was 300 cp, the pH 12.5, and the product was stable over prolonged standing periods at -5 and + 37 C.

WHAT WE CLAIM IS: 1. A homogeneous, aqueous built liquid detergent composition comprising: a) from 2-20% by weight of a synthetic detergent active compound; b) at least 4% by weight of sodium or tripolyphosphate; c) at least 2% by weight of sodium or potassium orthophosphate, the sum of b) and c) being from 635% by weight; d) 115% by weight of a hydrotrope selected from alkali metal or ammo nium toluene-, xylene-, cumene-sul phonate, urea, lower aliphatic C1-C4 monohydric alcohols and mixtures thereof; and e) 115% by weight of a hydrotrope selected from a C8-C18 fatty acid alkylolamide, a potassium soap of C,0-C23 fatty acids, and a potassium soap of dimerized C10-C,3 fatty acids.

2. A composition according to claim 1, comprising 515% by weight of a synthetic detergent active compound.

3. A composition according to claim 1 or 2, wherein the sum of b) and c) is 13-23% by weight.

4. A composition according to claims 1-3, wherein the weight ratio of b):c) is from 10:1 to 1:10.

5. A composition according to claim 4, wherein the weight ratio of b):c) is from 4:1 to 2:3.

6. A composition according to claim 5, wherein the weight ratio of b):c) is from 3:1 to 1:1.

7. A composition according to claims 16, comprising the hydrotrope d) in an amount of 5-10% by weight.

8. A composition according to claims 17, comprising potassium orthophosphate.

9. A composition according to claims 1 8, comprising at least 12% by weight of sodium tripolyphosphate.

10. A composition according to claim 9, wherein the sodium tripolyphosphate has a phase I content of more than 50% by weight.

11. A composition according to claims 110, comprising a potassium soap of coconut fatty acids or oleic acid.

12. A composition according to claims 110, comprising a potassium soap of dimerized oleic acid.

13. A composition according to claims 112, further comprising 0.1-5% by weight of an anti-deposition agent.

14. A composition according to claims 113, having a pH of 12-13.

15. A composition according to claims 114, substantially as described in the Examples.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (15)

**WARNING** start of CLMS field may overlap end of DESC **. The viscosity was 300 cp, the pH 12.5, and the product was stable over prolonged standing periods at -5 and + 37 C. WHAT WE CLAIM IS:

1. A homogeneous, aqueous built liquid detergent composition comprising: a) from 2-20% by weight of a synthetic detergent active compound; b) at least 4% by weight of sodium or tripolyphosphate; c) at least 2% by weight of sodium or potassium orthophosphate, the sum of b) and c) being from 635% by weight; d) 115% by weight of a hydrotrope selected from alkali metal or ammo nium toluene-, xylene-, cumene-sul phonate, urea, lower aliphatic C1-C4 monohydric alcohols and mixtures thereof; and e) 115% by weight of a hydrotrope selected from a C8-C18 fatty acid alkylolamide, a potassium soap of C,0-C23 fatty acids, and a potassium soap of dimerized C10-C,3 fatty acids.

2. A composition according to claim 1, comprising 515% by weight of a synthetic detergent active compound.

3. A composition according to claim 1 or 2, wherein the sum of b) and c) is 13-23% by weight.

4. A composition according to claims 1-3, wherein the weight ratio of b):c) is from 10:1 to 1:10.

5. A composition according to claim 4, wherein the weight ratio of b):c) is from 4:1 to 2:3.

6. A composition according to claim 5, wherein the weight ratio of b):c) is from 3:1 to 1:1.

7. A composition according to claims 16, comprising the hydrotrope d) in an amount of 5-10% by weight.

8. A composition according to claims 17, comprising potassium orthophosphate.

9. A composition according to claims 1 8, comprising at least 12% by weight of sodium tripolyphosphate.

10. A composition according to claim 9, wherein the sodium tripolyphosphate has a phase I content of more than 50% by weight.

11. A composition according to claims 110, comprising a potassium soap of coconut fatty acids or oleic acid.

12. A composition according to claims 110, comprising a potassium soap of dimerized oleic acid.

13. A composition according to claims 112, further comprising 0.1-5% by weight of an anti-deposition agent.

14. A composition according to claims 113, having a pH of 12-13.

15. A composition according to claims 114, substantially as described in the Examples.