BACKGROUND OF THE INVENTION In countries where textile fabrics are habitually washed by hand, even using premium products, the degree of cleaning achieved is frequently disappointing.

One route to improving handwash performance is to try to improve the ingredients in the main wash detergent formulation.

Clays are often added in small quantities as softening ingredients in detergent wash formulations. However in WO 01 44561 (Unilever) it is disclosed that cleaning performance can be enhanced by including clay in the rinse liquor. It is postulated that the clay remains on the clothes after they have dried and provides a sacrificial layer to which dirt adheres and so is more easily removed during subsequent washing the next time. This reduces a build-up of particulate soil on the textile.

Adding acids and bases, to provide effervescence, to detergent wash formulations is already known in the art, for example US 4 414 130 (Colgate-Palmolive), WO 92 18596

(Procter & Gamble), EP 534 525 (Unilever), WO 98 04662 (Procter & Gamble).

STATEMENT OF INVENTION The present inventors have now surprisingly discovered that the dispersion and deposition efficiency of such clays may be enhanced if accompanied by an alkali metal salt and organic acid which react together in solution to produce carbon dioxide gas. This may additionally act as a cue to the consumer, for example, to provide reassurance that some functional ingredient is present and effective in the liquor.

Thus a first aspect of the present invention provides a composition for treating textile fabrics, which comprises: (a) at least 10 wt% of a crystalline clay mineral; (b) at least 5 wt% of a combination of (b) (i) an alkali metal salt selected from carbonate, bicarbonate, sesquicarbonate and combinations thereof, and (b) (ii) a water-soluble organic acid which, when reacted with (b) (i) in solution, generates a water-soluble electrolyte and carbon dioxide gas; (c) optionally from 0 to 85 wt% of a water-soluble inorganic salt; the weight ratio of (b) (i): (b) (ii) being from 10: 1 to 1: 5.

Another aspect of the invention provides for a composition for treating textile fabrics, which comprises: (a) a crystalline clay mineral; (b) a combination of (b) (i) an alkali metal salt selected from carbonate, bicarbonate, sesquicarbonate and combinations thereof, and (b) (ii) a water-soluble organic acid which, when reacted with (b) (i) in solution, generates a water-soluble electrolyte and carbon dioxide gas; (c) optionally, a water-soluble inorganic salt; the weight ratio of (b) (i): (b) (ii) being from 10: 1 to 1: 5; the composition containing no more than 10 wt% synthetic non-soap surfactant.

Another aspect of the present invention provides a process for the treatment of textile fabrics, which comprises a step in which the textiles are immersed for at least 30 seconds in an aqueous solution of the composition defined above.

Another aspect of the invention provides the use of an alkali metal salt and an organic acid for enhancing the dispersion and/or deposition of clay onto a textile in an aqueous medium.

Another aspect of the invention provides for the use of an alkali metal salt, an organic acid and a crystalline clay mineral for the manufacture of a textile treatment composition, the composition upon addition to an aqueous

medium generates carbon dioxide gas and aids the dispersion and/or deposition of the clay.

DETAILED DESCRIPTION OF THE INVENTION The Crystalline Clay Mineral In the first aspect of the invention the crystalline clay mineral is present at a level of at least 10 wt%, preferably at least 20 wt%, more preferably at least 30 wt% and most preferably at least 40 wt%.

The crystalline clay mineral is preferably light coloured and has a reflectance of at least 60, preferably at least 70, more preferably at least 80 at a wavelength of 460 nm.

Ideally the crystalline clay mineral is white. For the purposes of the present invention, the reflectance was measured on a Macbeth Colour-eye 7000A reflectometer, although other methods may also be suitable.

The crystalline clay may be any appropriate mineral and preferably is selected from one or more clays selected from bi-layer clays (e. g. china clay and halloysite) which may be dioctahedral clays (such as kaolin) or trioctahedral clays (such as antigorite and amesite); tri-layer clays such as smectite and hormite, bentonite, beidelite, nontronite, hectorite, attapulgite, pimelite, mica, muscovite and vermiculite as well as pyrophyllite/talc, willemseite and minnesotaite clays. A preferred class of clays is bi-layer dioctahedral within which kaolin is especially preferred.

Preferably also, the number average particle diameter of the clay mineral particles should not exceed 5 pm, and preferably does not exceed 2 µm. This particle size diameter is that measured by use of a Malvern ZetasizerTM, using a dispersion of the clay mineral at 0.1 g/1 in deionised water at 25°C, the clay being dispersed by vigorous hand agitation using a glass rod stirrer for 1 minute.

The Alkali Metal Salt and the Organic Acid The alkali metal salt and the organic acid are capable of reacting together in solution to produce effervescent carbon dioxide gas and an electrolyte in solution. The alkali metal salt is most preferably selected from carbonate, bicarbonate, sesquicarbonate and combinations thereof.

There is preferably a sufficient concentration of the alkali metal salt and the organic acid in order to provide an acceptable amount of effervescence. Hence the combined amounts of alkali metal salt and organic acid is at least 5 wt% of the total composition. Preferably the combined amount is at least 10 wt% and more preferably at least 20 wt% of the total composition.

The alkali metal salt may have any suitable cation but it is preferred that it is a sodium salt.

The organic acid may be any suitable compound but is preferably non-hygroscopic, in order to improve storage stability. The acid is preferably water-soluble. Suitable

acids include citric, glutaric, succinic or adipic, however citric acid is preferred.

The weight ratio of the alkali metal salt (b) (i) to the organic acid (b) (ii) is in the range of from 10 : 1 to 1: 5.

Preferably they are present at a weight ratio of from 3: 1 to 1: 3 and even more preferably at a weight ratio of from 2: 1 to 1: 2.

Without wishing to be bound by theory it is believed that the produced effervescence enhances the dispersion and deposition of the clay onto the textile which has an effect above and beyond any enhanced dispersion and deposition effects due to the electrolyte produced. Furthermore the effervescence may provide a cue to the user that something special is happening, especially in a hand wash process.

The effervescence may also enhance the efficacy of any perfumes which may be present.

The Optional Water-Soluble Salt The optional water-soluble salt is believed to be beneficial because it further promotes dispersion and assists flocculation of the clay particles in the treatment solution and enables them to be uniformly dispersed and so deposit more uniformly on the textile.

Any non-surfactant water-soluble salt may be used. The term "non-surfactant"salt is used because many surfactants, e. g. anionic surfactants are in the form of water soluble alkali metal salts and cationic surfactants are usually in

water-soluble salt form with a counter-anion. For the non- surfactant water-soluble salts, salts of the metal cations with inorganic or organic anions are appropriate. A mixture of salts may also be used, but it is preferable to use a material which is widely available at low cost. Thus, one may use a soluble salt of a monovalent metal such as an alkali metal, for example sodium or potassium, e. g. as the chloride or sulphate. However, weight for weight, it is more effective to use a salt of a divalent metal, or a water-soluble salt of a metal having a valency of three or more; the tetravalent tetrasodium pyrophosphate being especially preferred. It could also be a water-soluble detergency builder such as an alkali metal citrate or tripolyphosphate.

If present, the salt may comprise any suitable level up to as much as 85 wt% of the full formulation. However, preferably the salt will be present at a level of from 5 to 20 wt%.

The Treatment Composition The treatment composition, which has as components the clay, the alkali metal salt and the organic acid, may also contain other optional ingredients. For example, clays which do not have the required level of whiteness may still be used if a clay whitening ingredient is also included. A whitening agent is a particulate material which is lightly coloured, preferably white. Examples of preferred whiteners are calcite, dolomite and titanium dioxide. Even if the clay is already white, such whiteners may still be included to

ensure the clay remains white during storage before use by the consumer.

The primary function of the composition of the present invention is to deposit clay on the textiles. Hence typically such compositions may contain no more than 10 wt% synthetic non-soap surfactant, preferably no more than 5 wt%, more preferably no more than 1 wt% and most preferably substantially zero wt%. If present, detergent- active compounds or surfactants may be chosen from soap and non-soap anionic, cationic, nonionic, amphoteric and zwitterionic detergent-active compounds, and mixtures thereof. 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. The preferred detergent-active compounds are soaps and synthetic non-soap anionic and nonionic compounds.

Anionic surfactants are well-known to those skilled in the art. Examples include alkylbenzene sulphonates, particularly linear alkylbenzene sulphonates having an alkyl chain length of Cl-ci ; primary and secondary alkylsulphates, particularly Cg-C15 primary alkyl sulphates; alkyl ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates.

Sodium salts are generally preferred.

Nonionic surfactants that may be used include the primary and secondary alcohol ethoxylates, especially the C8-C20 aliphatic alcohols ethoxylated with an average of from 1 to 20 moles of ethylene oxide per mole of alcohol, and more especially the C1o-Cls primary and secondary aliphatic alcohols ethoxylated with an average of from 1 to 10 moles of ethylene oxide per mole of alcohol. Non- ethoxylated nonionic surfactants include alkylpolyglycosides, glycerol monoethers, and polyhydroxyamides (glucamide).

Detergency builders may also be included. Those which are water-soluble salts may form all or part of the optional water-soluble salt (c). The composition of the invention may also contain an alkali metal, preferably sodium, aluminosilicate builder. If present it is preferably within the range of from 10 to 80 wt%, preferably from 15 to 70 wt% and more preferably from 20 to 60 wt%. The alkali metal aluminosilicate may be either crystalline or amorphous or mixtures thereof, having the general formula: 0.8-1.5 Na20. A1203. 0. 8-6 Si02 These materials contain some bound water and are required to have a calcium ion exchange capacity of at least 50 mg CaO/g. The preferred sodium aluminosilicates contain 1.5-3.5 SiO2 units (in the formula above). Both the amorphous and the crystalline materials can be prepared readily by reaction between sodium silicate and sodium aluminate, as amply described in the literature.

The crystalline materials (zeolites) are preferred. The preferred detergent zeolites are zeolites A (4A), X, and, most preferably, maximum aluminium zeolite P (zeolite MAP) as described and claimed in EP 384 070B (Unilever).

Zeolite MAP is defined as an alkali metal aluminosilicate of the zeolite P type having a silicon to aluminium ratio not exceeding 1.33, and preferably not exceeding 1.07. The calcium binding capacity of zeolite MAP is generally at least 150 mg CaO per g of anhydrous material.

Supplementary builders may also be present. These are generally organic. Organic builders that may be present include polycarboxylate polymers such as polyacrylates, acrylic/maleic copolymers, and acrylic phosphinates; monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono-, di-and trisuccinates, carboxymethyloxysuccinates, carboxymethyloxymalonates, dipicolinates, hydroxyethyliminodiacetates, alkyl-and alkenylmalonates and succinates; and sulphonated fatty acid salts.

Compositions of the present invention optionally may contain one or more additional benefit agents. These may, for example, be selected from fluorescers, perfumes, starches, enzymes such as lipases, antiredeposition, anti-dye-transfer and soil release polymers, bleaches, photobleaches and blueing agents.

Any fluorescer present is preferably incorporated in an amount of from 0.01 to 1% by weight of the composition, although the upper limit of this range is more preferably

0.75%, still more preferably 0.5%, most preferably 0. 1% by weight of the composition. Typical perfume levels are from 0. 1% to 1%, e. g. from 0.2% to 0.5% by weight of the composition.

The compositions of the present invention may be provided in any suitable form to allow convenient dispersion/solution in the water by the consumer. Thus, for example, they may be provided as powders, granulated solids, bars or tablets.

The compositions may be provided in a product form whereby they are provided alongside a main wash product, for example comprising a detergent surfactant, a detergency builder and optionally, other detergent ingredients. Conveniently, the main wash product and the composition according to the present invention may be provided in respective secondary packaging inside a unitary primary package.

The Treatment Process The composition of the invention is intended to be added to water in order for the effervescent pair to react together to produce an in-situ electrolyte and evolved carbon dioxide gas. The treatment step of the invention involves the immersion of the textile in the solution for a minimum of 30 seconds.

This treatment step may also be preceded by a wash step.

The treatment step may also be preceded by a rinse step, wherein the process step of the invention is the last rinse step. The treatment step of the invention is preferably carried out by hand. If the process is carried out by hand

then the dispersion of the composition preferably does not need to be assisted by hand action.

EXAMPLES Examples 1 to 3 and Comparative Examples A and B Cotton and polycotton textiles were treated with the compositions shown in Table 1, giving a total of ten treated textiles. Examples 1-3 are within the invention and were compared to Examples A and B.

Table 1 Example Ingredient 1 2 3 A B 46.89 53.97 57.71 88.90 - China clay Sodium carbonate 18.75 21.59 23.08 - - 15.38 17.70 18.93 - - Citric acid Magnesiumsulphate - - - - - Sodiumchloride - - - - - 18.75 6.48 - 10.67 - TSPP Photine C 0.19 0.22 0.23 0.36 - Blue 0.04 0.04 0.05 0.07 - Product 5.34 4.64 4.34 2.82 - concentration (g/l) Clay 2.5 2.5 2.5 2.5 - concentration (g/l)

The clay used was China clay, India clay"A" (ex. English India China Clay). The alkali metal salt used was sodium carbonate (ex Saurastra Chemicals). The organic acid used was citric acid (ex. Ranbaxy Chemicals). The inorganic water-soluble salts used were magnesium sulphate (ex. Loba Chemie), sodium chloride (ex. Gujarat Heavy Chemicals) and tetrasodium pyrophosphate (TSPP) (ex. Albright & Wilson).

The fluorescer used was Photine (Trade Mark) C (ex Hickson & Dadaji). The blueing agent was Vitasyn patent blue V85 CI42051 (ex. Clariant).

Experimental Protocol The following three steps constitute one cycle of treating, soiling and washing. The protocol consists of a total of four such cycles.

Step 1: Treatment A clean cotton textile and a clean polycotton textile were subjected to compositions 1,2,3 and A in a aqueous medium and in Example B no composition was used. This stage was carried out on clean textiles for cycle 1, and thereafter on the washed textiles for cycles 2,'3 and 4. After drying, the textiles were exposed to soiling.

Step 2: Soiling The treated textiles were then placed on purpose built racks, and exposed on an open, but covered, terrace located within the confines of Hindustan Lever Research Centre,

Mumbai, India. This soiling method imitates the environmental soiling conditions experienced by consumers in urban environments. The samples were subjected to an exposure period of 2 days, before being removed for washing.

The cotton textiles (five out of ten) were further subjected to soiling by a model sebum.

Step 3: Washing The textiles were washed by hand at a liquor to cloth ratio of 5: 1 in a wash water at 24°FH (with the ratio of calcium to magnesium ions being at 2: 1) with a commercially available detergent composition at a concentration of 5 g/1 at a wash temperature of 28°C.

Ten textiles were treated according to the experimental protocol detailed above. Five of them (Examples 1 to 3 for both cotton and polycotton) were treated with a composition of the present invention, two of them (Comparative Example A for both cotton and polycotton) were treated with compositions that did not provide effervescence, and two (Comparative Example B for both cotton and polycotton) were rinsed only in water.

The reflectance values of the textiles was measured using a Macbeth Colour-eye 7000A reflectometer, at a wavelength of 460 nm, after cycle one and cycle four. The reflectance measurements are shown in Table 2.

Table 2 Reflectance values Textile 1 2 3 A B cotton after 96. 6 95.1 88.3 92.0 93.9 cycle one cotton after 90.5 92.1 90.1 90.9 87.6 cyclefour polycotton after 95.7 94. 2 93.4 94.4 93.6 cycle one polycotton after 91.1 90.8 89.8 91.5 89.7 cycle four