WO2009050026A2

WO2009050026A2 - Laundry compositions

Info

Publication number: WO2009050026A2
Application number: PCT/EP2008/063019
Authority: WO
Inventors: Sivakumar Ananthasubramanian; Olaf Cornelis P Beers; Sankha Subrha Roy Choudhury; Stephen Thomas Keningley; Ronladus Theodorus L Van Vliet
Original assignee: Unilever Nv; Unilever Plc; Hindustan Unilever Limited
Priority date: 2007-10-17
Filing date: 2008-09-29
Publication date: 2009-04-23
Also published as: WO2009050026A3

Abstract

The present invention relates to laundry detergent compositions, and has as an object to provide detergent compositions comprising alkyl ester fatty acid sulphonate surfactants, having improved dissolution properties. The invention provides a detergent granule comprising alkyl ester fatty acid sulphonate and alkyl benzene sulphonate.

Description

LAUNDRY COMPOSITIONS

The present invention relates to compositions, specifically the present invention relates to laundry detergent compositions comprising a combination of an alkyl ester fatty acid sulphonate and alkyl benzene sulphonate and methods of making and using the same.

Sulphofatty acid esters in detergent compositions are known in the art. WO 0192457 (Huish Detergents) discloses sulphofatty acid esters in combination with a basic material to reduce the formation of disalts and hence improve the properties of the composition.

US 6534464 (Huish Detergents) discloses a detergent composition comprising particles of a polyalkoxylated alkanolamide and particles of a sulphofatty acid ester admixed to reduce disalt formation and hence improve the cleaning performance in hard water while sparing the need for builders.

US 6509310 (Huish Detergents) discloses a tablet detergent composition comprising a methyl ester sulphonate a second portion comprising at least one basic material with minimal contact between them to reduce disalt formation and hence improve the properties of the composition.

Fine grade sulphofatty acid esters are difficult to handle in mass processing as they are dusty and they are ultimately lump forming in such processing environments. However the coarser grade larger particle size and longer chain sulphofatty acid esters inhibit the dissolution of formulations comprising such esters. There remains a need in detergent compositions containing such larger particle size and longer chain sulphofatty acid esters to have improved solubility.

It has now surprisingly been found that a laundry composition with the particular combination of alkyl ester fatty acid sulphonate and alkyl benzene sulphonate provides a surfactant mix that is more soluble and therefore provides more effective detergency, better dissolution, better foaming and fewer residues.

According to a first aspect of the invention there is provided a detergent granule comprising alkyl ester fatty acid sulphonate and alkyl benzene sulphonate at a ratio of less than 90:10, wherein the detergent granule comprises an amount of surfactant of from 70 to 100 wt%.

According to a second aspect of the invention there is provided a laundry detergent composition comprising from 1 to 20 wt% of the detergent granule as outlined above.

According to a third aspect of the invention there is provided a process of making a detergent granule as outlined above, comprising molecular mixing of an alkyl ester sulphonate and alkyl benzene sulphonate.

According to a fourth aspect of the invention there is provided the use of a detergent granule as outlined above to improve the dissolution of the alkyl ester fatty acid sulphonate. The detergent granule

The detergent granule comprises alkyl ester fatty acid sulphonate and alkyl benzene sulphonate at a ratio of less than 90:10, preferably the alkyl ester fatty acid sulphonate and alkyl benzene sulphonate are at a ratio of 85:15 to 50:50, more preferably 85:15 to 60:40, and most preferably 80:20 to 70:30.

The granule may also comprise salts such as sulphates, and carbonates. It may also comprise granulating aids, polymers such as polyethylene glycol, sodium toluene sulphate, sodium xylene sulphate, and polyacrylates . It may also comprise dissolution aids and binders such as aqueous polymer solutions, and flow aids such as silicates, and zeolite.

The granule has a pH in a 5% solution of granule in dialysed water of 3 to 8, preferably 4 to 6. At high pHs namely a pH of greater than 8, and especially greater than 10 methyl ester fatty acid sulphonate will degrade which can lead to loss of ingredient. Previously methyl ester fatty acid sulphonate when incorporated into spray dried compositions which are formulated at a pH of 8 to 11 is prone to decomposition or malodour problems. This detergent granule is used to improve the dissolution of the alkyl ester fatty acid sulphonate .

The detergent granule comprises an amount of surfactant of from 70 to 100 wt%. Preferably, the detergent granule comprises an amount of surfactant of from 70 to 97 wt%, more preferably from 70 to 96 wt%, and most preferably from 70 to 95 wt%. - A - The anionic surfactants

Alkyl ester fatty acid

The sulphonated alkyl ester may be pure alkyl ester sulphonate or a blend of a mono-salt of a sulphonated alkyl ester of a fatty acid having from 16 to 26 carbon atoms where the alkyl portion forming the ester is a straight or branched chain alkyl of 1 to 6 carbon atoms and a disalt of a sulphonated fatty acid. The ratio of monosalt to disalt being at least 2:1 and up to about 25:1. The sulphonated alkyl esters used are typically prepared by sulphonating an alkyl ester of a fatty acid with a sulphonating agent such as SO₃. When prepared in this way the sulphonated alkyl esters normally contain a minor amount of the disalt of the sulphonated fatty acid which results from hydrolysis of the ester. Preferred sulphonated alkyl esters contain less than about 10% by weight of the disalt of the corresponding sulphonated fatty acid.

The sulphonated alkyl esters, include linear esters of C16 to C26 carboxylic acid which are sulphonated with gaseous SO3 according to the Journal of American oil Chemists Society 52 (1975) pp 323-329. Suitable starting materials would include natural fatty substances as derived from tallow, palm oil, coconut etc

The preferred alkyl ester sulphonate or fatty acid sulphonate surfactants comprise alkyl sulphonate surfactants of the type methyl ester fatty acid sulphonate (MES), having the formula:

where Ak = predominantly linear Cs - C20 alkyl chain, preferably C16 - Cis.

The IUPAC name for e.g. a so-called C16 MES is Hexadecanoic acid, 2-sulfo-, 1-methylester, sodium salt (Ci₇H₃₃NaO₅S) .

Methyl ester sulphonate can be obtained by sulphonation of various renewable oleo-based methyl ester feedstocks derived from e.g. coconut (C12-14), palm kernel (C8-18), palm stearin (C16-18) or tallow (C16-18) . Besides the renewable origin, MES is of special interest due to good biodegradability, detergency and calcium hardness tolerance.

Methods of preparing α-sulfofatty acid esters are known to skilled artisan. (See, e.g., US-A-5 587 500; US-A-5 384 422; US-A-5 382 677; US-A-5 329 030; US-A-4 816 188; and US-A- 4 671 900; and The Journal of American Oil Chemists Society 52:323-29 (1975) the disclosures of which are incorporated herein by reference) . α-Sulfofatty acid esters can be prepared from a variety of sources, including beef tallow, palm kernel oil, palm kernel (olefin) oil, palm kernel (stearin) oil, coconut oil, soybean oil, canola oil, cohune oil, coco butter, palm oil, white grease, cottonseed oil, corn oil, rape seed oil, soybean oil, yellow grease, mixtures thereof or fractions thereof. Suitable fatty acids to make α- sulfofatty acid esters include, but are not limited to, caprylic (Cs) , capric ( (C10) , lauric (C12) , myristic (Ci₄) , myristoleic (Ci₄) , palmitic (Ciε) , palmitoleic (Ciε) , stearic (Cis) , oleic (Cis) , linoleic (Cis) , linolenic (Cis) , ricinoleic (Cis) , arachidic (C20) , gadolic (C20) , behenic (C22) , and erucic (C22) fatty acids. α-Sulfofatty acid esters prepared from one or more of these sources are within the scope of the present invention.

Samples of alkyl ester fatty acid sulphonate surfactant prepared in dry powder form via above mentioned production processes typically contain about 75-85 % by weight of the desired surfactant.

Methyl ester sulphonate can be supplied in such a manner that it comprises a low average particle size, that is that it has a particle size of less than 500μm. Methyl ester sulphonate can be supplied in such a manner that it comprises a higher average particle size, that is that it has a particle size of greater than 500μm, these are sometimes termed coarse grade granules of methyl ester sulphonate. Particular benefits in terms of dissolution can be seen in the present invention with the higher average particle size methyl ester sulphonate granules when these granules are formulated according to the invention. In a preferred embodiment of the invention the alkyl ester fatty acid comprises an average particle size of greater than 500μm.

LAS

The alkyl benzene sulphonate may be branched for example tetrapropylenebenzenesulphonate or linear for example linear alkyl benzene sulphonate. Preferably the alkyl benzene sulphonate is linear alkyl benzene sulphonate. The laundry detergent composition

The laundry detergent composition comprises from 1 to 20 wt%, preferably from 1 to 10 wt% of the detergent granule.

Other surfactants

The composition may also comprise one or more other surfactants. The other surfactant is present in an amount of from 0.5 to 40 wt%, preferably from 5 to 30 wt%, based on the weight of the total composition.

Surfactants are well-known to those skilled in the art. Many suitable detergent-active compounds are available and are fully described in the literature, for example, in "Surface- Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch.

Examples include alkylbenzene sulphonates, branched or linear alkyl benzene sulphonates, primary and secondary alcohol sulphates, particularly C8-C16 primary alcohol sulphates; alkyl ether sulphates, olefin sulphonates, including alpha olefin sulphonates, alkane sulphonates, alkyl xylene sulphonates, dialkyl sulphosuccinates, and alkyl carboxylates . These may be present as sodium, potassium, calcium or magnesium salts or mixtures of these. Sodium salts are generally preferred.

The other surfactant is preferably a sulphonate or sulphate anionic surfactant or a combination thereof. More preferably, the anionic surfactant is linear alkylbenzene sulphonate or primary alkyl sulphate. Most preferably the other surfactant is linear alkylbenzene sulphonate. The linear alkyl benzene sulphonate may be present as sodium, potassium, or alkaline earth metal salts, or mixtures of these salts. Sodium salts are generally preferred.

The other surfactant may also comprise a nonionic surfactant, preferably an ethoxylated alcohol nonionic surfactant with an average degree of ethoxylation ranging from about 3 to 9, preferably from about 3 to 7. The alcohol may be derived from natural or synthetic feedstock. Preferred alcohol feedstocks are coconut and palm kernel, predominantly C12-C14, and oxo C12-C15 alcohols.

The nonionic surfactant is suitably present in an amount of from 1 to 20 wt %, preferably from 1 to 10, more preferably from 2 to 6 wt %, most preferably from 3 to 5 wt %, based on the weight of the total composition.

Additional surfactants or detergent active compounds may comprise other nonionics such as alkylpolyglucosides, polyhydroxyamides (glucamide) , methyl ester ethoxylates and glycerol monoethers . Also cationic, amphoteric surfactants and/or zwitterionic surfactants may be present. Preferred cationic surfactants are quaternary ammonium salts of the general formula R1R2R3R4N₊ X_, for example where Ri is a C12-C14 alkyl group, R2 and R3 are methyl groups, R₄ is a 2-hydroxyethyl group, and X- is a chloride ion. This material is available commercially as Praepagen (Trade Mark) HY from Clariant GmbH, in the form of a 40 wt% aqueous solution.

Preferred amphoteric surfactants are amine oxides, for example coco dimethyl amine oxide. Preferred zwitterionic surfactants are betaines, and especially amidobetaines . Preferred betaines are C8 to C18 alkyl amidoalkyl betaines, for example coco amido betaine. These may be included as co- surfactants, preferably present in an amount of from 0 to 10 wt %, more preferably 1 to 5 wt %, based on the weight of the total composition.

Detergency builder

The compositions may suitably contain from 10 to 80%, preferably from 15 to 70% by weight, of detergency builder. Preferably, the quantity of builder is in the range of from 15 to 50% by weight.

Preferably the builder is selected from sodium tripolyphosphate, zeolite, sodium carbonate, sodium citrate, layered silicate, and combinations of these.

The zeolite used as a builder may be the commercially available zeolite A (zeolite 4A) now widely used in laundry detergent powders. Alternatively, the zeolite may be maximum aluminium zeolite P (zeolite MAP) as described and claimed in EP 384 070B (Unilever), and commercially available as Doucil (Trade Mark) A24 from Ineos Silicas Ltd, UK. Zeolite MAP is defined as an alkali metal aluminosilicate of zeolite P type having a silicon to aluminium ratio not exceeding 1.33, preferably within the range of from 0.90 to 1.33, preferably within the range of from 0.90 to 1.20. Especially preferred is zeolite MAP having a silicon to aluminium ratio not exceeding 1.07, more preferably about 1.00. The particle size of the zeolite is not critical.

Zeolite A or zeolite MAP of any suitable particle size may be used. Also preferred according to the present invention are phosphate builders, especially sodium tripolyphosphate . This may be used in combination with sodium orthophosphate, and/or sodium pyrophosphate.

Other inorganic builders that may be present additionally or alternatively include sodium carbonate, layered silicate, amorphous aluminosilicates .

Organic builders that may be present include polycarboxylate polymers such as polyacrylates and acrylic/maleic copolymers; polyaspartates; monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono-di- and trisuccinates, carboxymethyloxysuccinates, carboxy- methyloxymalonates, dipicolinates, hydroxyethyliminodiacetates, alkyl- and alkenylmalonates and succinates; and sulphonated fatty acid salts.

Organic builders may be used in minor amounts as supplements to inorganic builders such as phosphates and zeolites. Especially preferred supplementary organic builders are citrates, suitably used in amounts of from 5 to 30 wt%, preferably from 10 to 25 wt%; and acrylic polymers, more especially acrylic/maleic copolymers, suitably used in amounts of from 0.5 to 15 wt%, preferably from 1 to 10 wt%.

Builders, both inorganic and organic, are preferably present in alkali metal salt, especially sodium salt, form.

Other detergent ingredients

As well as the surfactants and builders discussed above, the compositions may optionally contain bleaching components and other active ingredients to enhance performance and properties .

These optional ingredients may include, but are not limited to, any one or more of the following: soap, peroxyacid and persalt bleaches, bleach activators, sequestrants, cellulose ethers and esters, other antiredeposition agents, sodium sulphate, sodium silicate, sodium chloride, calcium chloride, sodium bicarbonate, other inorganic salts, fluorescers, photobleaches, polyvinyl pyrrolidone, other dye transfer inhibiting polymers, foam controllers, foam boosters, acrylic and acrylic/maleic polymers, proteases, lipases, cellulases, amylases, other detergent enzymes, citric acid, soil release polymers, fabric conditioning compounds, coloured speckles, and perfume.

Detergent compositions according to the invention may suitably contain a bleach system. The bleach system is preferably based on peroxy bleach compounds, for example, inorganic persalts or organic peroxyacids, capable of yielding hydrogen peroxide in aqueous solution. Suitable peroxy bleach compounds include organic peroxides such as urea peroxide, and inorganic persalts such as the alkali metal perborates, percarbonates, perphosphates, persilicates and persulphates . Preferred inorganic persalts are sodium perborate monohydrate and tetrahydrate, and sodium percarbonate . Especially preferred is sodium percarbonate having a protective coating against destabilisation by moisture. Sodium percarbonate having a protective coating comprising sodium metaborate and sodium silicate is disclosed in GB 2 123 044B (Kao) . The peroxy bleach compound is suitably present in an amount of from 5 to 35 wt%, preferably from 10 to 25 wt%.

The peroxy bleach compound may be used in conjunction with a bleach activator (bleach precursor) to improve bleaching action at low wash temperatures. The bleach precursor is suitably present in an amount of from 1 to 8 wt%, preferably from 2 to 5 wt%.

Preferred bleach precursors are peroxycarboxylic acid precursors, more especially peracetic acid precursors and peroxybenzoic acid precursors; and peroxycarbonic acid precursors. An especially preferred bleach precursor suitable for use in the present invention is N, N, N', N'- tetracetyl ethylenediamine (TAED) . Also of interest are peroxybenzoic acid precursors, in particular, N, N, N- trimethylammonium toluoyloxy benzene sulphonate.

A bleach stabiliser (heavy metal sequestrant) may also be present. Suitable bleach stabilisers include ethylenediamine tetraacetate (EDTA) and the polyphosphonates such as Dequest (Trade Mark), EDTMP.

The detergent compositions may also contain one or more enzymes. Suitable enzymes include the proteases, amylases, cellulases, oxidases, peroxidases and lipases usable for incorporation in detergent compositions.

In particulate detergent compositions, detergency enzymes are commonly employed in granular form in amounts of from about 0.1 to about 3.0 wt%. However, any suitable physical form of enzyme may be used in any effective amount. Antiredeposition agents, for example cellulose esters and ethers, for example sodium carboxymethyl cellulose, may also be present.

The compositions may also contain soil release polymers, for example sulphonated and unsulphonated PET/POET polymers, both end-capped and non-end-capped, and polyethylene glycol/polyvinyl alcohol graft copolymers such as Sokolan (Trade Mark) HP22. Especially preferred soil release polymers are the sulphonated non-end-capped polyesters described and claimed in WO 95 32997A (Rhodia Chimie) .

In a preferred embodiment of the invention the detergent composition further comprises (i) from 5 to 30 wt%, preferably from 10 to 15 wt%, of an anionic surfactant,

(ii) from 0.5 to 10 wt%, preferably from 1 to 5 wt%, of a non-ionic surfactant, (iii) from 10 to 60 wt%, preferably from 15 to 40 wt%, of a detergency builder, (iv) from 0 to 60 wt%, preferably from 10 to 30 wt%, of an inorganic non-builder salt, (v) from 0.5 to 3 wt%, preferably from 1 to 2 wt%, of a polycarboxylate polymer, and(vi) optionally other detergent ingredients to 100 wt%.

Product form and preparation

The compositions of the invention may be of any suitable physical form, for example, particulates (powders, granules, tablets) or bars.

According to one especially preferred embodiment of the invention, the detergent composition is in particulate form. In a preferred embodiment of the invention there is a process of making a detergent granule comprising molecular mixing of an alkyl ester sulphonate and linear alkyl benzene sulphonate. The alkyl ester and/or the linear alkyl benzene may be sulphonated either before, after or during the molecular mixing. The linear alkyl benzene sulphonate and alkyl ester fatty acid sulphonate are prepared as an intimate or molecular mixture that is the materials cannot easily be separated. This can be achieved in many ways, for example the organic feedstocks (Methyl Ester and Linear Alkylbenzene) can be mixed prior to sulphonation or post sulphonation moreover the pastes of the salts of methyl ester sulphonate can be mixed with the salts of linear alkylbenzene sulphonate. Mixing can be achieved by the use of static or dynamic mixers as a batch or continuous operation.

Powders of low to moderate bulk density may be prepared by spray-drying slurry, and optionally post dosing (dry-mixing) further ingredients. The detergent granule according to the invention may be added at any stage of this process. In a preferred embodiment the detergent granule is post dosed, that is added as an adjunct to the composition.

Routes available for powder manufacture include Spray Drying, Drum Drying, Fluid Bed Drying, and Scraped Film Drying devices such as the Wiped Film Evaporator. A preferred form of scraped film device is a wiped film evaporator. One such suitable wiped film evaporator is the "Dryex system" based on a wiped film evaporator available from Ballestra S. p. A.. Alternative equipment would be the Chemithon the "Turbo Tube" dryer system wherein a high active surfactant paste is heated and metering to a multi tube, steam-j acketed drying vessel. "Concentrated" or "compact" powders may be prepared by mixing and granulating processes, for example, using a high-speed mixer/granulator, or other non-tower processes.

Tablets may be prepared by compacting powders, especially "concentrated" powders.

Examples

The invention is illustrated in further detail by the following non-limiting examples, in which parts and percentages are by weight unless otherwise stated.

Methyl ester fatty acid sulphonate as used in the following examples is from Huish, which is a sodium C_±β methyl ester sulphonate (89% pure, having an average molecular weight of 371 g/mol), abbreviated to MES.

Different types of LAS are used in the following examples, i.e. sodium linear alkyl benzene sulphonate (with an average chain length of C12) ; Nansa HS90PF from Huntsman, 92% pure, abbreviated to NaLAS, or linear alkyl benzene sulphonic acid (with an average chain length of C12) ; Marlon AS3 from Chemproha, 100% pure, abbreviated to HLAS.

Preparation of molecular MES/LAS granules

Molecular MES/LAS mixtures were on lab-scale obtained by drying of thin layers of 20% aqueous solutions. Table 1 shows the amounts of MES and LAS used in order to obtain 300 ml of 20% solutions of MES/LAS. The solutions were obtained by mixing the surfactants for about 60 minutes in 300 ml demineralised water at 45°C. MES and NaLAS were used as obtained from the supplier and were compensated for the purity, i.e. 89% and 92% respectively. The LAS-acid was neutralized with 50% NaOH to pH=±10 prior to addition of MES However, the pH-value of all final MES/LAS solutions was about 5.

Thin layers of the aqueous solutions were obtained by transferring into plastic trays of 36cm x 40cm. These were dried at 45°C for about 65 hours. The obtained flakes were milled into powder with a Sirman miller. The obtained powder was sieved into different fractions namely <250μm, 250 < x < 500μm and 500 < x < lOOOμm.

Table 1

20% aqueous solutions of MES/LAS

Dissolution properties

The dissolution properties of the various sieve fractions of all MES/LAS granules were determined by measuring the level of insoluble material. Therefore 0.555 - 0.694 grams MES/LAS granule was added on top of 5 grams of a mixture of dry powder ingredients, see Table 2 below, (without LAS, silicate and perfume) , which delivered powder samples with about 10% MES. The amount of MES/LAS granule is chosen such to have the same MES delivery in solution, and hence is dependent on the MES/LAS-ratio, which is shown in Table 3 below.

Each powder sample was mixed thoroughly by hand. Then the powder was dissolved for 2 min, while stirring with a 4 cm vortex using a magnetic stirrer, in 500 ml demineralised water at 20⁰C and 30⁰FH (Ca:Mg=2 : 1) . After 2 min dissolving, the solution was filtered under vacuum using a 125 μm sieve. The sieve with residue is dried for at least 8 hours at 45°C. The level of the insoluble material could now be measured.

Dissolution is expressed as %insolubles, i.e. (weight of residue) / (weight of product) x 100%.

Table 2

Mixture of dry powder ingredients (without LAS, silicate and perfume)

The dissolution properties of Ci6 MES with particle sizes between 250 < x < 500μm and 500 < x < lOOOμm can be improved by mixing with LAS on a molecular scale. A MES/LAS ratio of less than 90:10 is required to obtain enhanced dissolution.

Table 3

Amounts of MES/LAS granules used for %insoluble-measurements

Results

Claims

1. A detergent granule comprising alkyl ester fatty acid sulphonate and alkyl benzene sulphonate at a ratio of less than 90:10, wherein the detergent granule comprises an amount of surfactant of from 70 to 100 wt%.

2. A detergent granule as claimed in claim 1, wherein the alkyl ester fatty acid comprises an average particle size of greater than 500μm.

3. A detergent granule as claimed in any preceding claim, wherein the detergent granule comprises an amount of surfactant of from 70 to 97 wt%, more preferably from 70 to 96 wt%, and most preferably from 70 to 95 wt%.

4. A detergent granule as claimed in any preceding claim, wherein the alkyl ester fatty acid is methyl ester fatty acid sulphonate

5. A detergent granule as claimed in claim 4, wherein the methyl ester fatty acid sulphonate has a carbon chain length of C_±β to Cis.

6. A detergent granule as claimed in any preceding claim, wherein the methyl ester fatty acid sulphonate and alkyl benzene sulphonate are at a ratio of 85:15 to 50:50, preferably 85:15 to 60:40, most preferably 80:20 to 70:30.

7. A detergent granule as claimed in any preceding claim, wherein the pH of a 5% solution of the granule is from 3 to 8, preferably from 4 to 6.

8. A laundry detergent composition which comprises from 1 to 20 wt%, preferably 1 to 10 wt%, of the detergent granule in any of claims 1 to 7.

9. A laundry detergent composition as claimed in claim 8, wherein the detergent granule is post-dosed.

10. A laundry detergent composition as claimed in claim 8 or claim 9, wherein it further comprises

(i) from 5 to 30 wt%, preferably from 10 to 15 wt%, of an anionic surfactant,

(ii) from 0.5 to 10 wt%, preferably from 1 to 5 wt%, of a non-ionic surfactant,

(iii) from 10 to 60 wt%, preferably from 15 to 40 wt%, of a detergency builder,

(iv) from 0 to 60 wt%, preferably from 10 to 30 wt%, of an inorganic non-builder salt,

(v) from 0.5 to 3 wt%, preferably from 1 to 2 wt%, of a polycarboxylate polymer, and

(vi) optionally other detergent ingredients to 100 wt%.

11. A process of making a detergent granule as claimed in any of claims 1 to 7, comprising molecular mixing of an alkyl ester sulphonate and alkyl benzene sulphonate.

12. Use of a detergent granule as claimed in any of claims 1 to 7, to improve the dissolution of the alkyl ester fatty acid sulphonate.