EP1115833A1

EP1115833A1 - Detergent composition

Info

Publication number: EP1115833A1
Application number: EP99947291A
Authority: EP
Inventors: Dirk Johannes Unilever Research Vlaardingen BIJL; Johannes C. Unilever Res. Vlaardingen PAS VAN DE; Charles C. Unilever Res. Vlaardingen VERBURG; Johannes J. Unilever Res. Vlaardingen VERHAGEN; Pieter Unilever Res. Vlaardingen VERSLUIS; Petronella C. Unilever Res.Vlaardingen WISSENBURG
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 1998-09-25
Filing date: 1999-09-08
Publication date: 2001-07-18
Anticipated expiration: 2019-09-08
Also published as: TR200100847T2; WO2000018868A1; ES2230892T3; DE69922672T2; CA2345644A1; ATE284949T1; BR9913923A; DE69922672D1; AU6080699A; CN1354784A; ZA200101410B; EP1115833B1

Abstract

There is provided a structured liquid detergent composition with (i) less than 10 % volume phase separation after 21 days at 25 DEG C from the time of preparation; (ii) a viscosity lower than 500 mPa.s at a shear rate of 21 s-1; and (iii) a Dissolution Time - as measured herein - of less than 120 seconds while being stable without deflocculating polymer. In addition a process is provided to clean laundry using said composition.

Description

DETERGENT COMPOSITION

Technical field

The present invention relates to detergent compositions, in particular to structured liquid detergent compositions.

Background & Prior Art

Liquid detergent compositions offer several advantages over granular detergent compositions. For example, liquid compositions are easy to dose and give confidence to the consumer of being safe to the fabrics. This may be the reason why heavy duty and light duty built laundry liquid detergent products have gained a great popularity ever since their introduction on the market.

There are two general and separate classes of liquid detergent compositions, isotropic and structured liquids. Isotropic liquids are liquids in which all ingredients are dissolved and, contrary to structured liquids, there is no structure present in isotropic liquid.

In structured liquids, structuring may be brought about to endow properties such as consumer preferred flow properties and/or turbid appearance. Many structured liquids are also capable of suspending particulate solids. Examples of structured liquids are given in US-A-4244840, EP-A-0160342 , EP-A-0038101 and EP-A-0140452. Structured liquids can be "internally structured", whereby the structure is formed by primary ingredients, preferably by surfactant material, and/or "externally structured" whereby a three dimensional matrix structure is provided by using secondary additives, preferably polymers, clay, silica and/or silicate material. Externally structured liquids may provide a high viscosity upon storage.

In general, the degree of ordering of surfactant containing systems increases with increasing surfactant and/or electrolyte concentrations. At very low concentrations of surfactant and/or electrolyte, the surfactant can exist as a molecular solution, or as a solution of spherical micelles, both of these solutions being isotropic, i.e. they are not structured. With the addition of further surfactant and/or electrolyte structures of surfactant material may form. Various forms of such structures exists, e.g. bi-layers. They are referred to by various terms such as rod-micelles, anisotropic surfactant phase, planar lamellar structures, lamellar droplets and liquid crystalline phases. Various examples of liquids, which are internally structured with surfactant material, are given in H.A. Barnes, "Detergents", Ch. 2. in K. Walters (Ed), "Rheometry: Industrial Applications", J. Wiley & Sons, Letchworth 1980. Often different workers have used different terminology to refer to the structures which are really the same. For instance, in European patent specification EP-A-0151884 , lamellar droplets are called spherulites.

A preferred lamellar structure is characterised by lamellar droplets of surfactant material in an aqueous continuous phase wherein the dispersed structuring phase is generally believed to consist of an onion-like configuration comprising concentric bilayers surfactant molecules, between which water is trapped, the aqueous phase. Liquids with a lamellar droplets structure are preferred as systems in which such droplets are close-packed providing a very desirable combination of physical stability with useful flow properties, i.e., good pourability combined with adequate stability. Such liquids have, for example, been described in A. Jurgens, Micro-structure and Viscosity of Liquid Detergent, Tenside Surfactants Detergent 26 (1989), page 222 and J.C. van de Pas, Liquid Detergents, Tenside Surfactants Detergents 28 (1991), page 158. The presence and identity of a surfactant structuring system in a liquid may be determined by means known to those skilled in the art for example, optical techniques, various rheometrical measurements, X-ray or neutron diffraction, and sometimes, electron microscopy.

The large number of interactions between the ingredients of liquid detergent compositions generally makes it difficult to prepare compositions which are chemically and physically stable, especially upon storage. Such detergent compositions may become inhomogeneous, e.g. ingredients may separate out by crystallisation or precipitation. Another aspect of liquid detergents is their dissolution behaviour. Thus far, little attention has been paid to the dissolution behaviour of liquid detergents. When a detergent composition is used, consumers prefer to see it rapidly dissolve in water. This assures the user that the detergent composition quickly becomes fully active. Structured liquid detergent compositions already dissolve more rapidly than powdered detergents. But for liquid detergent compositions that may be used for hand-wash applications including laundry, an excellent dissolution behaviour is required. Low viscous liquids detergents such as pure nonionic surfactants show a complicated and poor dissolution behaviour via the formation of mesophases. Another example wherein the dissolution may also be problematic is in the case of lamellar structured liquid detergents which also consist of mesophases. Although we do not wish to be bound by any theory, we believe that the dissolution of structured liquid detergents comprising lamellar droplets can be divided in two phases. In the first phase of the dilution the droplets disperse and in the second phase the droplets disintegrate. However, the dilution with water may cause a decrease in the salt concentration outside the lamellar droplets. This may result in swelling of the lamellar droplets due to the osmotic pressure. Such a process could help to explain the poor dissolution of some structured liquid detergents.

Many structured liquid detergent compositions are capable of suspending solids such as zeolite. However, such compositions pose significant problems with regard to rheology and stability because the solids should remain suspended over at least 1-3 weeks while the compositions should remain pourable. However, suspension of solids is not always needed. Structured liquid detergents that do not contain stably suspended solids may then be preferred because these compositions do not have to fulfil such stringent requirements and may therefore be easier to formulate. However, most prior art is related to structured liquids having stably suspending solids. EP-A-301 882 discloses structured liquid detergent compositions having stably suspended solids such as 20 wt% zeolite. The dissolution behaviour of the compositions is not disclosed. EP-A-362 916 relates to the incorporation of high levels of a functional polymer to counteract the effects of fabric softening clays. The compositions exemplified are capable of suspending solids. The dissolution behaviour of the resulting compositions is unclear. EP-A-829 530 describes structured hard surface cleaning compositions contain stably suspended solids. It contains no disclosure regarding the dissolution behaviour of the exemplified compositions. EP-A-74 134 discloses structured liquid detergent composition having stably suspended solids. The patent describes that sodium sulphite can be used in compositions with high levels of sodium triphosphate (25 to 26%) if sodium xylene sulphonate or sodium toluene sulphonate is used to obtain the right viscosity and good stability. Again, there is no disclosure on the dissolution behaviour of the disclosed compositions.

Thus, there is still a need for stable structured liquid detergent compositions which do not contain stably suspended solids, have good dissolution properties, and which do not exhibit one or more of the drawbacks mentioned above.

Surprisingly, we have now found that it is possible to formulate stable structured liquid detergent which show an excellent dissolution rate if the viscosity is maintained below 500 mPa . s at a shear rate of 21 s^"1, said composition being essentially free from deflocculating polymer and stably suspended solids.

Definition of the invention

The present invention relates to a stable, structured liquid detergent composition characterised in that:

(i) the composition will yield less than 10 % volume phase separation after 21 days at 25 °C from the time of preparation; and (ii) the viscosity is lower than 500 mPa.s at a shear rate of 21 s^_1; and (iii) upon dissolution of 10 ml of the composition in 2.5 litre water at 25 °C and 4 °FH, the Dissolution Time - as measured herein - is less than 120 seconds; and (iv) if the composition comprises a Viscosity Reducing Polymer, then the Viscosity Reducing Polymer does not consist solely of dextran, dextran sulphonate or polyethylene glycol; provided that when the composition consists of 10.4 wt% sodium dodecyl benzene sulphonate, 6.7 wt% C12-13 fatty alcohol alkoxylated with an average of 7 moles ethylene oxide per molecule, 4.6 wt% of sodium chloride, then the composition comprises at least one builder that does not consist solely of sodium polyacrylate with a Mw of 1200 to 8000; said composition being essentially free from deflocculating polymers and stably suspended solids In this context, compositions with stably suspended solids are compositions that are able to suspend 20 wt% of zeolite 4A for 3 wks at 25°C under normal pressure without showing more than 2% of an upper layer which contains less zeolite than the bottom layer.

Yet another embodiment provides for a process to clean laundry using a liquid detergent composition according the present invention.

Detailed description of the invention

The relatively low dissolution rate of aqueous structured liquid detergent compositions may be a major consumer- perceived drawback. A high dissolution rate may assure the consumer that the liquid detergent composition is properly dissolved and therefore completely active. This applies in general to all liquid detergent compositions but in particular for liquid detergent compositions that are suitable for hand wash applications. A favourable dissolution rate is when the Dissolution Time (as measured below) is less than 120, preferably less than 100, more preferably less than 90, more preferably less than 80, even more preferably less than 60 seconds. According the present invention 10 ml liquid detergent is dosed with a regular flow via a syringe to a beaker of 3 litre (diameter 14 cm) filled with 2.5 litres of water of 4 °FH at 25 °C. The water in the beaker is stirred with a magnetic stirrer (rod of 6 cm length) in such a way that a vortex of 1 cm is formed in the centre of the beaker. The liquid detergent is dosed outside the vortex. The electrical conductivity is recorded as function of time, 1 cm from the wall of the beaker till constant reading (all liquid detergent is dissolved) . From the data the Dissolution Time is calculated by taking the time to reach 90% of the equilibrium conductivity value, i.e., when 90% by weight of the composition is dissolved.

We have now found that limiting the viscosity of the liquid detergent compositions to a particular level is a surprisingly significant factor in formulating liquid detergent compositions with a favourable dissolution rate.

Viscosity reduction

The viscosity of the composition of the present invention may be controlled by various methods known in the art. In a preferred embodiment the composition comprises Viscosity Reducing Polymer as described in EP-A-0301882. The Viscosity Reducing Polymer is able to reduce the viscosity of the composition by more than 5% when measured at a shear rate of 21 S^"1, in comparison with an identical composition except that all such polymer is omitted. A number of different polymers may be used, provided the electrolyte resistance and vapour pressure requirements are met. The former is measured as the amount of sodium nitrilotriacetate (NaNTA) solution necessary to reach the cloud point of 100 ml of a 5% solution of the polymer in water at 25°C, with the system adjusted to neutral pH, i.e. about 7. This is preferably effected using sodium hydroxide. Most preferably the electrolyte resistance is 10 g NaNTA, especially 15g. The latter requirement indicates a vapour pressure low enough to have sufficient water binding capability, as generally explained in the applicants' specification GB-A-2, 053, 249. Thus, the polymer preferably has a vapour pressure in 20% aqueous solution equal to or less than the vapour pressure of a reference 10% by weight aqueous solution of polyethylene glycol having an average molecular weight of 6000. It needs to be emphasised that, in contrast to the present invention, EP-A-0301882 discloses how to use Viscosity Reducing Polymer to improve the pourability of the liquids (page 2, line 43) without mentioning possible effects on the dissolution behaviour. In a preferred embodiment the composition according the present invention comprises more than 0.01%, preferably more than 0.05%, more preferably more than 0.1% and less than 10%, preferably less than 5%, more preferably less than 2.5% by weight of Viscosity Reducing Polymer. In many compositions (but not all) levels above these can cause instability.

The Viscosity Reducing Polymer may be selected from the group consisting of polyacrylates, polysaccharides, modified polysaccharides, polyalkyleneoxydes, polyvinylpyrrolidone, copolymers such as poly (acrylate-co- maleate) , poly (acrylate-co-styrene) and poly (ethylene terephtalate-co-ethylene oxide) and mixtures thereof. Examples of suitable polymers include: Sokalan PA50™, Sokalan CP5™ (both ex BASF), Narlex LD31™ and Narlex H1200™ (both ex National Starch) , Alcosperse 725™ (ex National Starch) , sodium carboxylmethyl cellulose, inuline, PEG 1500 and Aquaperle (ex ICI). Alternatively, the composition according the present invention is formulated according conventional means to reduce the viscosity including the following options or any combination of the following options:

(i) Increasing of the electrolyte level in the formulation. A possible drawback is that too high an electrolyte level may cause physical instability with as end result layer separation upon storage. In turn, there are several routes to repair this physical instability, these routes include addition of salting-in electrolytes (e.g. EP-A-00796 6) , addition of salting-out resistant surfactants (e.g. EP-A- 0328177) and the addition of deflocculating polymers (e.g. EP-A-0346995 and EP-A-0623670) (ii) Decreasing surfactant level (iii) Changing the surfactant ratio. For example, in a composition containing anionic(s) and nonionic(s) a viscosity reduction may be obtained by both an decrease and an increase of the anionic/nonionic surfactant ratio. It will depend on the position of the formulation in the compositional diagram what the best route is to bring about viscosity reduction by this route. A person skilled in the art will by simple experimentation find the best practical means to reduce the viscosity by this route. (iv) Changing the ratio of the cations. Often the cations are sodium and potassium, sometimes tri- or mono- ethanolamine . A change of the cations, e.g. an increase of the potassium/sodium ratio, may result in an increase of the dissolved concentration of electrolyte (when part of the electrolyte is present as crystals). This may reduce viscosity according to route (i) and or by a reduction of the amount of solids particles when crystal dissolution takes place . (v) Adding small amounts of hydrotropic agents including sodium xylene sulphonate, ethanol, propylene glycol and the like (e.g. EP-A-0491723) . The amounts of hydrotropes must not be too high otherwise the product will suffer from physical instability. It is believed that reduction of the viscosity via this route is caused by an increase of the flexibility of the lamellar bilayers resulting in an increase of the deformability of the lamellar droplets. However, on addition of a too high level of hydrotrope the integrity of the bilayer is lost with as a result a breakdown of the lamellar droplets and physical instability.

Surfactant Material

Liquid detergent compositions of the invention comprise surfactant materials, preferably at a level of at least 1% by weight of the composition, more preferred at least 5% by weight, most preferred at least 10% by weight of the composition; and preferably at a level of at most 80% by weight, more preferably at most 40%, most preferably at most 35% by weight.

In the widest definition the detergent-active material in general, may comprise one or more surfactants, and may be selected from anionic, cationic, nonionic, 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. 1. By Schwartz & Perry, Interscience 1949 and 'Surface Active Agents' Vol. II by Schwarz, Perry & Berch (Interscience 1958), in the current edition of "McCutcheon' s Emulsifiers & Detergents" published by the McCutcheon division of Manufacturing

Confectioners Company, in 'Tensid-Taschenbuch' , H. Stache, 2nd Edn., Carl Hanser Verlag, Mϋnchen & Wien, 1981 or US-A- 5750733.

Suitable nonionic surfactants 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 alkyl (C₆-C₁₈) 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 phospine oxides, alkylpolysaccharides and dialkyl sulphoxides. Preferably, the level of nonionic surfactant materials is at least 1%, more preferred at least 2%, even more preferred at least 5%, most preferred at least 10%, and at most 80%, more preferred at most 50%, even more preferred at most 30% by weight of the composition.

Suitable anionic surfactants 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 (Cβ-Ciβ) alcohols produced, for example, from tallow or coconut oil, sodium and potassium alkyl (C₉- C₂₀) benzene sulphonates, particularly sodium linear secondary alkyl (Cι₀-Cι₅) 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; ethercarboxylates ; sodium coconut oil fatty monoglyceride sulphates and sulphonates; sodium and potassium salts of sulphuric acid esters of higher (C₈-Cι₈) 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 monosulphonates such as those derived by reacting alpha- olefins (C₈-₂o) with sodium bisulphite and those derived from reacting paraffins with S0₂ 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 Cι₀-C₂₀ alpha-olefins, with S0₃ and then neutralising and hydrolysing the reaction product. The preferred anionic detergent compounds are sodium (Cu-Cis) alkyl benzene sulphonates and sodium (Cι₆-Cι₈) alkyl sulphates. Generally the level of the above mentioned non-soap anionic surfactant material is at least 1%, more preferred at least 2%, even more preferred at least 5%, even more preferred at least 8%, most preferred at least 10%, and at most 80%, more preferred at most 40% and even more preferred at most 25% by weight of the composition.

Also possible is that part or all of the detergent active material is a stabilising surfactant, which has an average alkyl chain length greater than 6 C-atoms, and which has a salting out resistance, greater than, or equal to 6.4. These stabilising surfactants are disclosed in our European patent application EP-A-328 , 177. Examples of these materials are alkyl polyalkyloxated carboxylates, alkyl polyalkoxylated phosphates, alkyl polyalkoxylated sulphosuccinates; dialkyl diphenyloxide disulphonates; alkyl polysacccharides and mixtures thereof. It is also possible, and sometimes preferred, to include 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. Preferably the level of soap is at least 1%, preferably at least 5% by weight of the composition, and at most 35%, preferably at most 25% by weight of the composition .

Electrolyte Material

Compositions according to the invention may comprise electrolyte material, some or all of which may be builder material. It is noted that for the purpose of the invention, the term electrolytes may include builder material .

Preferably, liquid detergent compositions according to the invention comprise salting-out electrolyte having a lyotropic value of less than 9.5 and preferably less than 9.0. Salting-out electrolyte has the meaning ascribed in specification EP-A-0079646. Preferred salting-out electrolytes are selected from alkali metal and ammonium salts of phosphates (including pyro, ortho and poly phosphates), silicates, borates, carbonates, sulphates, citrates, NTA and succinates. Preferably, the liquid compositions contain at least 1% by weight of a salting-out electrolyte, more preferably at least 2%, most preferably at least 5% by weight and preferably at most 30% by weight, more preferably at most 20% by weight of a salting-out electrolyte. Optionally, some salting-in electrolyte (as defined in the latter specification) may also be included.

Preferably, the total level of electrolyte is at least 1%, more preferred at least 5%, most preferred at least 10% and at most 60%, more preferred at most 45% and most preferred at most 30% by weight.

In any event, it is preferred that compositions according to the present invention include detergency builder material, some or all of which may be electrolyte. In this context it should be noted that some surfactant materials such as for example soaps, also have builder properties. Preferably, the builder material is selected from soap and non-soap builder material. The compositions according the invention are built. Preferably, the level of total builder material is from 0.1 to 60% by weight of the composition, more preferred from 0.5 to 50% by weight of the composition and even more preferred from 2 to 30% by weight of the composition. Preferably, the builder material is water soluble.

Non-soap builder materials are for example of inorganic detergency builders with or without phosphor. Examples of phosphorous-containing inorganic detergency builders include the water-soluble salts, especially alkali metalpyrophosphates, orthophosphates, polyphosphates and phosphonates . Examples of non phosphorus-containing inorganic detergency builders, when present, include water- soluble alkali metal carbonates, bicarbonates, silicates and crystalline and amorphous aluminosilicates . Examples of organic detergency builders, when present, include the alkaline metal, ammonium and substituted ammonium polyacetates, carboxylates, polycarboxylates, polyacetyl carboxylates and polyhydroxysulphonates .

It is preferred that when the composition contains a builder, the builder does not consist solely of sodium polyacrylate of Mw 1200-8000.

Preferably, the level of non-soap builder material is from 1 to 40% by weight of the composition, more preferred from 3 to less than 24% by weight of the composition.

The use of deflocculating polymer (sometimes referred to as stabiliser), has been disclosed before e.g. in WO 91/06622, WO 91/06623, GB-A-2237813, WO 91/09109, PCT Application No. EP/93/01882 and/or EP-A-0346995 including end-capped deflocculating polymer as described in e.g., EP-A-0623670 US-A-5489397, EP-A-691399 and/or GB Application No.

9711849.1. The liquid detergent composition of the present invention is essentially free from deflocculating polymer. This means that generally, the composition comprises less than 0.01%, more preferably less than 0.001% and even more preferably 0.0001% by weight of said deflocculating polymer.

Preferably, the composition according the present invention is internally structured, more preferably, the composition comprises lamellar droplets of surfactant material in an aqueous continuous phase. Optional Ingredients

Apart from the ingredients already mentioned, a number of optional ingredients may also be present, for example lather boosters, lather depressants, oxygen-releasing bleaching agents such as sodium perborate and sodium percarbonate, peracid bleach precursors, chlorine-releasing bleaching agents such as trichloroisocyanuric acid, inorganic salts such as sodium sulphite and, usually present in very minor amounts, fluorescent agents, perfumes, enzymes such as proteases, amylases, cellulases and upases (including Lipolase (Trade Mark) ex Novo) , enzyme stabilisers, anti-redeposition agents, soil release agents, anti dye transfer agents, germicides and colorants.

Although we prefer that no fabric softening, swelling clay be present, if included at less than 5% by weight, the clay containing material may be any such material capable of providing a fabric softening benefit. Usually these materials will be of natural origin containing a three- layer swellable smectite clay which is ideally of the calcium and/or sodium montmorillonite type. It is preferable to exchange the natural calcium clays to the sodium form by using sodium carbonate, either before of during granulation, as described in GB-A-2138037 (Colgate) . The effectiveness of a clay containing material as a fabric softener will depend inter alia on the level of smectite clay. Impurities such as calcite, feldspar and silica will often be present. Relatively impure clays can be used provide that such impurities are tolerable in the composition.

Product Forms Liquid compositions of the invention preferably have a viscosity of less than 500 mPa . s at 21 s^_1, more preferred less than 450 mPa . s at 21 s^-1, most preferred less than 400 mPa.s at 21 s^"1 and preferably higher than 10 mPa . s at 21 s^~ ^l , more preferably higher than 50 mPa . s at 21 s^"1. Liquid detergent compositions according to the invention are stable, i.e. the compositions will yield less than 10 %, preferably less than 5 %, most preferred less than 2% by volume phase separation as evidenced by appearance of 2 or more separate phases when stored at 25 °C for 21 days from the time of preparation.

Preferably, the pH, as provided to the wash liquor, preferably by a liquid, is at least 6, more preferably at least 6.5, most preferably at least 7. Preferably, the pH is at most 12, more preferably at most 11, more preferably at most 10, more preferably at most 9.

Preferably, the liquid compositions of the invention comprise water at levels of at least 10%, more preferably at least 20%, most preferably at least 30% by weight of the composition. Preferably, the liquid compositions of the invention comprise water at levels of at most 80%, more preferably at most 70%, most preferably at most 60% by weight of the composition. Preferably, the liquids are concentrated. Process to clean laundry

Another embodiment encompasses a process to clean laundry using the liquid detergent composition according the present invention. Preferably, the laundry is cleaned by hand in said process.

Other than in the examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term "about". Similarly, all percentages are by weight unless otherwise indicated. The term "comprise" is intended to have an open-ended character, i.e., if a composition comprises X, other ingredient (s) may also be present in the composition in addition to X.

The following examples are illustrative of the invention.

Examples

.^'comparative example)

Raw materials LAS-acid approx. C12 alkyl benzene sulphonic acid, (ex Hύls or Industrial Gessy Lever Ltd, Brazil)

LES Sodium lauryl ether (approx. 3 ethylene oxide) sulphate, Manro Bes 70 ex Hickson Manro or Genapol LRO B. (ex Clariant S.A., (Brazil) STP Sodium Tri (Poly) Phosphate, Thermphos

NW, ex Knapsack or ex Copebras S.A. (Brazil) Sokalan PA50™ sodium polyacrylate, ex BASF Sodium Sulphate ex Crimidesa S.A. (Spain) Propylene Glycol ex Dow Quimica S.A. (Brazil) Borax ex Merck

Claims

1. A stable, structured liquid detergent composition characterised in that:

(i) the composition will yield less than 10 % volume phase separation after 21 days at 25 °C from the time of preparation; and (ii) the viscosity is lower than 500 mPa . s at a shear rate of 21 s^_1; and (iii) upon dissolution of 10 ml of the composition in 2.5 litre water at 25 °C and 4 °FH, the Dissolution Time - as measured herein - is less than 120 seconds; and (iv) if the composition comprises a Viscosity

Reducing Polymer, then the Viscosity Reducing Polymer does not consist solely of dextran, dextran sulphonate or polyethylene glycol; provided that when the composition consists of 10.4 wt% sodium dodecyl benzene sulphonate, 6.7 wt% C12-13 fatty alcohol alkoxylated with an average of 7 moles ethylene oxide per molecule, 4.6 wt% of sodium chloride, then the composition comprises at least one builder that does not consist solely of sodium polyacrylate with a Mw of 1200 to 8000; said composition being essentially free from deflocculating polymers and stably suspended solids.

2. A composition according to any preceding claim, wherein the viscosity is lower than 450 mPa . s . , preferably lower than 400 mPa . s . , at a shear rate of 21 s^"1.

3. A composition according to any preceding claim, wherein the Dissolution Time - as measured herein - is less than 100 seconds, preferably less than 80 seconds .

4. A composition according to any preceding claim, wherein the composition comprises a Viscosity Reducing Polymer having an electrolyte resistance and vapour pressure as herein described.

5. A composition according to claim 4, wherein the composition comprises more than 0.01% and less than 10%, preferably more than 0.05% and less than 5% by weight of the composition of Viscosity Reducing Polymer .

6. A composition according to claims 4 and 5, wherein the Viscosity Reducing Polymer is selected from the group consisting of polyacrylates, polysaccharides, modified polysaccharides, polyalkyleneoxydes, polyvinylpyrrolidone, copolymers such as poly (acrylate-co-maleate) , poly (acrylate-co-styrene) and poly (ethylene terephtalate-co-ethylene oxide) and mixtures thereof.

7. A composition according to claim 1, wherein the liquid detergent composition is internally structured.

8. A composition according to claim 7, wherein the liquid detergent composition comprises lamellar droplets of surfactant material in an aqueous continuous phase.

9. A composition according to any preceding claim, characterised in that the composition comprises from 0.1 to 60% of builder material by weight of the composition selected from soap and non-soap builder material .

10. A composition according to any preceding claim characterised in that the composition comprises at least 8% and at most 25% by weight of the composition of non-soap anionic surfactant material.

11. A composition according to claim 1 characterised in that the composition comprises a) 0.1 to 60% of builder material by weight of the composition selected from soap and non-soap builder material. b) at least 8% and at most 25% by weight of the composition of non-soap anionic surfactant material . c) comprises more than 0.01% and less than 10% by weight of the composition of Viscosity Reducing Polymer preferably selected from the group consisting of polyacrylates, polysaccharides, modified polysaccharides, polyalkyleneoxydes, polyvinylpyrrolidone, copolymers such as poly (acrylate-co-maleate) , poly (acrylate-co- styrene) and poly (ethylene terephtalate-co- ethylene oxide) and mixtures thereof.

12. Process to clean laundry using a liquid detergent composition according to any of the preceding claims.

13. Process according claim 12 wherein the laundry is cleaned by hand.