Technical Field

The present invention relates to a granule made by drying of double or inverse emulsions, particularly to a granule containing a benefit agent, such as a polysaccharide, to a process for manufacturing the granule and to the use of the granules, for example in a laundry treatment composition.

Background of the Invention

PCT application number PCT/EP03/13641 is directed towards a process for the preparation of polysaccharide grafted latex particles which comprises conventional emulsion polymerisation and to the materials thus produced. The particles have been used as carriers for benefit agents, including softeners, for deposition under main wash conditions. However, constraints on the amount of benefit agents which can be incorporated into the particles and the types of monomer units that can be used, which are inherent to conventional emulsion polymerisation, are inevitable.

WO 0232563 describes the stabilisation of granules obtained by drying a multiple emulsion. The emulsions comprise an internal aqueous phase, an oily phase including 5% surfactant stabiliser and the external aqueous phase initially including Arlatone F127G, a non-ionic polyalkoxylated amphiphilic polymer from ICI and Geropon T36, a maleic anhydride/diisobutylene copolymer with molecular weight of 5000, used as emulsifier and /or stabilising agent.

In WO 9116359 it has been proposed to use the polysaccharide: Cellulose Mono-Acetate (CMA) , as a benefit agent in a laundry composition. More recently in WO 00 18861 it has been proposed to modify the CMA by grafting silicone onto it.

WO 03049846 describes a process for forming double emulsion particles which could be useful for delivery of modified polysaccharides such as CMA or silicone graft CMA. A problem with double emulsions of this type is that it is very difficult to granulate them to make them suitable for inclusion in a powdered detergent formulation. In particular they are difficult to dry effectively at large scale. The oily phase is stabilised by Arlatone F127G.

EP 0239378, teaches using salts in the internal water phase of an emulsion in order to facilitate the rehydration of a dried double emulsion.

Definition of the Invention

According to the present invention there is provided a process for the granulation of a double emulsion or inverse emulsion of a benefit agent including the steps of: adding an aqueous solution of an organic salt with a molecular weight of less than 400, preferably less than 250, and optionally a polysaccharide salt, to the emulsion and then, spray drying the dispersion so formed to make granules containing the organic salt .

The polysaccharide salt may be sodium caseinate.

The organic salt is preferably a trisodium salt of a tricarboxylic acid, and more preferably sodium citrate.

The benefit agent is advantageously a polysaccharide, especially a polysaccharide with /3-1,4 linkages.

The granule may usefully be included in a detergent composition.

Also according to the present invention there is provided a granule comprising a dried double or inverse emulsion the inner aqueous phase containing a benefit agent and a stabilising surfactant, the oil phase comprising a stabilising surfactant and the granule comprising from at least 1% by weight preferably from 5 to 25% by weight, more preferably from 10 to 20% by weight, of an organic salt of molecular weight less than 400, preferably less than 250.

The organic salt is preferably a trisodium salt of a tricarboxylic acid, most preferably sodium citrate. The granule may further comprises a polysaccharide salt . The organic salt is advantageously located on the external surface of the granule. Advantageously the organic salt is sodium citrate as this gives a viscosity reduction to the dispersion which allows rapid and effective spray drying to form particles of ideal diameter, allowing rapid redispersion of the granules and re-hydration and formation of the double emulsion.

The Benefit Agent

The benefit agent may be anything that is required to be delivered from an emulsion system. It may, in a preferred embodiment of the invention, be a polysaccharide which is to be applied to a fabric during laundering. It may provide one or more of the following benefits to the fabric: stiffening, starching, softening, drape modifying, lubricating, elastomeric, shape retention, crease reduction, ease of ironing, moisturising, colour preservation and anti- pilling, depending on the specific particle monomers utilised.

Furthermore, in addition to the polysaccharide or in place of it the benefit agent could be a material which may enhance the benefit (s) conferred by the polysaccharide and/or confer further benefit (s) .

The benefit agent may be any agent that is capable of imparting desirable properties to the substrate it is applied to. Preferably, the benefit agent is a fabric benefit agent capable of affecting the feel, appearance, or perception of a fabric. The fabric benefit agent, may be selected from, but is not limited to, the following: fabric softeners, lubricants, ease of ironing aids, stiffening agents, moisturising agents, shape retention aids, crease reduction agents, anti-pilling agents, colour preservatives, perfumes, drape modifiers, fluorescers, sunscreens, photofading inhibitors, fungicides and insect repellents.

Suitable fabric softeners are amino functional silicone oils such as Rhodorsil Oil Extrasoft supplied by Rhodia Silicones. Other silicones may be selected from those disclosed GB 1,549, 180A, EP 459,821A2 and EP 459822A. These silicones can also be used as lubricants. Other suitable lubricants include any of those known for use as dye bath lubricants in the textile industry.

When used as a benefit agent, the polysaccharide preferably has a β-l,4-linked backbone. Preferably the polysaccharide is a cellulose, a cellulose derivative, or another β-1,4- linked polysaccharide having an affinity for cellulose, such as polymannan, polyglucan, polyglucomannan, polyxyloglucan and polygalactomannan. More preferably, the polysaccharide is selected from the group consisting of polyxyloglucan and polygalactomannan. For example, preferred polysaccharides are locust bean gum, tamarind xyloglucan, guar gum or mixtures thereof. Most preferably, the polysaccharide is CMA.

The polysaccharide may act as a delivery aid/deposition agent for the particle and/or any other benefit agent present.

Preferably, the polysaccharide backbone has only β-1,4 linkages. Optionally, the polysaccharide has linkages in addition to the β-1,4 linkages, such as β-1,3 linkages. Thus, optionally some other linkages are present. Polysaccharide backbones which include some material which is not a saccharide ring are also within the ambit of the present invention, whether terminal or within the polysaccharide chain.

The polysaccharide may be straight or branched. Many naturally occurring polysaccharides have at least some degree of branching, or at any rate at least some saccharide rings are in the form of pendant side groups, which are therefore not in themselves counted in determining the degree of substitution, on a main polysaccharide backbone.

Preferably, the polysaccharide is present at levels of between 0.1% to 10% w/w by weight of the granule, preferably 2% w/w by weight.

The polysaccharide may be grafted to a polymer. By grafted as used herein, in the context of the invention, is meant attached. Attachment may be by means of a covalent bond, entanglement or strong adsorption, preferably by a covalent bond or entanglement and most preferably by means of a covalent bond. By entanglement as used herein is meant that the polysaccharide is adsorbed onto the particle and part of the adsorbed polysaccharide is buried within the interior of the particle. Hence, part of the polysaccharide is entrapped and bound in the particle polymer matrix, whilst the remainder is free to extend into the aqueous phase. By strong adsorption as used herein is meant strong adsorption of the polysaccharide to the surface of the particle; such adsorption can, for example, occur due to hydrogen bonding, Van der Waals or electrostatic attraction between the polysaccharide chains and the particle.

The grafted polysaccharide is thus mainly attached to the particle surface and is not, to any significant extent, distributed throughout the internal bulk of the particle. This is distinct from graft copolymers in which a polysaccharide may be grafted along the length of a polymer chain. A particle which is formed from a graft copolymer would, therefore, contain polysaccharide throughout the internal bulk of the particle as well as on the particle surface. Thus the particle of the invention can be thought of as a "hairy particle" , which is different from a graft copolymer. This feature of the invention provides significant cost reduction opportunities for the manufacturer as much less polysaccharide is required to achieve the same level of activity as systems which utilise polysaccharide copolymers.

The Double or Inverse Emulsion

The emulsion can be prepared following the method described in WO 03 049846. The emulsion comprises an inner water phase 'including the polysaccharide and a stabilising system including surfactant . This is surrounded by an oil phase comprising silicone oil and, in turn, the oil phase is distributed as an emulsion in water. Usually a film forming material is included in the external water phase and also an antimicrobial and possibly a further surfactant, such as an amphiphilic surfactant.

The Granulation Process

To an emulsion, preferably a double emulsion such as that described above, is added water and dissolved in the water an organic salt with molecular weight less than 400, preferably less than 250. Advantageously the organic salt is a trisodium salt of a tricarboxylic acid, preferably sodium citrate. Optionally a sodium salt of polysaccharide, preferably sodium caseinate, is also dissolved or dispersed in the water.

When the optional high molecular weight caseinate is used, the organic salt should be used in an amount to give a ratio of: organic salt: caseinate/polysaccharide salt from 0.5:1 to 2:1, preferably about 0.8:1.2. In a particular embodiment containing the caseinate the ratios of salt to caseinate to oil to stabilising surfactant are: organic salt : caseinate : oil : water : non ionic = 0.4 : 0.6 : 1.0 : 4.4 : 0'.04.

When used, the level of caseinate may be in the range 25 to 50% in the final granule (after drying) .

The caseinate may be substituted by non-ionic stabiliser. Generally the amounts of material in the final granule and in the mix to be dried vary only by the amount of water present, the water being the main change during the drying process. Typically as little water as possible is added to the system, for example the water content before spray- drying should be in the range 65 to 95% by weight of the liquor. The amounts of materials present in the resulting granule are discussed below.

Without wishing to be bound by theory it is believed that the viscosity modification and/or the increase in electrolyte concentration caused by introduction of the organic salt allows rapid drying of the particles without breaking the emulsion. It does this by removal of water through osmotic pressure and also by forming a film (with the film forming polymer already present in the emulsion) , which is sufficiently water permeable to allow rapid drying of the emulsion particles and without allowing the oil droplets to begin to coalesce into larger particles which ■ would then suffer from poor dispersion and performance when redispersed in a wash liquor. Furthermore the use' of this drying technique beneficially modifies the particle size and the particle size distribution of the particles obtained which improved both their stability and their wash performance.

The Granule

The granule comprises a dried double or inverse emulsion, the inner aqueous phase containing the benefit agent and a stabilising surfactant, the oil phase comprising a stabilising surfactant and the granule comprising from 5 to 50% by weight, preferably from 10 to 30% by weight, of an organic salt of molecular weight less than 400, preferably less than 250. Typically the organic salt will be on the outer surface of the granule at a level of about 10 to 20% by weight .

The organic salt is preferably a trisodium salt of a tricarboxylic acid, most preferably sodium citrate. The granule may further comprises a polysaccharide salt. The organic salt is advantageously located on the external surface of the granule.

The maximum water level in the granule should be no more than 25%, preferably no more than 15% and more preferably no more than 10% or even 5% by weight. The lowest possible amount of water may be about 2% if spray drying is used with the organic salt at a high level .

When present the optional caseinate will be used in an amount of from 25 to 50%. The caseinate may be substituted by increased levels of non-ionic stabiliser. The ratio of non-ionic to organic salt should lie in the range 1:25 to 25:1.

The balance of the granule will usually comprise the emulsion and stabilising system together with any benefit agents carried in the emulsion.

The organic salt will preferably be on the outside of the granule and should be in between the double/inverse emulsion droplets of the granule. Laundry Treatment Compositions

The granules may be incorporated into laundry treatment compositions.

The granules are typically included in said compositions at levels of from 0.001% to 10%, preferably from 0.005% to 5%, most preferably from 0.01% to 3% by weight of the total composition.

The active ingredient in the laundry treatment compositions is preferably a surface active agent or a fabric conditioning agent. More than one active ingredient may be included. For some applications a mixture of active ingredients may be used.

The compositions of the invention may be in any physical form e.g. a solid such as a powder or granules, a tablet, a solid bar, a paste, gel or liquid, especially, an aqueous based liquid. In particular the compositions may be used in laundry compositions, especially in liquid, powder or tablet laundry composition.

The compositions of the present invention are preferably laundry compositions, especially main wash (fabric washing) compositions or rinse-added softening compositions. The main wash compositions may include a fabric softening agent and the rinse-added fabric softening compositions may include surface-active compounds, particularly non-ionic surface-active compounds. The detergent compositions of the invention may contain a surface-active compound (surfactant) which may be chosen from soap and non-soap anionic, cationic, non-ionic, amphoteric and zwitterionic surface-active compounds and mixtures thereof. Many suitable surface-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 that can be used are soaps and synthetic non-soap anionic, and non-ionic compounds .

The compositions of the invention may contain linear alkylbenzene sulphonate, particularly linear alkylbenzene sulphonates having an alkyl chain length of from C8 to C15. It is preferred if the level of linear alkylbenzene sulphonate is from 0 wt% to 30 wt%, more preferably from 1 wt% to 25 wt%, most preferably from 2 wt% to 15 wt%, by weight of the total composition.

The compositions of the invention may contain other anionic surfactants in amounts additional to the percentages quoted above. Suitable anionic surfactants are well-known to those skilled in the art. Examples include primary and secondary alkyl sulphates, particularly C8 to C15 primary alkyl sulphates; alkyl ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates. Sodium salts are generally preferred. The compositions of the invention may also contain non-ionic surfactant. Nonionic surfactants that may be used include the primary and secondary alcohol ethoxylates, especially the C8 to C20 aliphatic alcohols ethoxylated with an average of from 1 to 20 moles of ethylene oxide per mole of alcohol, and more especially the ClO to Cl5 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) .

It is preferred if the level of non-ionic surfactant is from 0 wt% to 30 wt%, preferably from 1 wt% to 25 wt%, most preferably from 2 wt% to 15 wt%, by weight of the total composition.

Any conventional fabric conditioning agent may be used in the compositions of the present invention. The conditioning agents may be cationic or non-ionic. If the fabric conditioning compound is to be employed in a main wash detergent composition the compound will typically be non¬ ionic. For use in the rinse phase, typically they will be cationic. They may for example be used in amounts from 0.5% to 35%, preferably from 1% to 30% more preferably from 3% to 25% by weight of the composition.

Suitable cationic fabric softening compounds are substantially water-insoluble quaternary ammonium materials comprising a single alkyl or alkenyl long chain having an average chain length greater than or equal to C20 or, more preferably, compounds comprising a polar head group and two alkyl or alkenyl chains having an average chain length greater than or equal to C14. Preferably the fabric softening compounds have two long chain alkyl or alkenyl chains each having an average chain length greater than or equal to C16. Most preferably at least 50% of the long chain alkyl or alkenyl groups have a chain length of C18 or above. It is preferred if the long chain alkyl or alkenyl groups of the fabric softening compound are predominantly linear.

Quaternary ammonium compounds having two long-chain aliphatic groups, for example, distearyldimethyl ammonium chloride and di (hardened tallow alkyl) dimethyl ammonium chloride, are widely used in commercially available rinse conditioner compositions. Other examples of these cationic compounds are to be found in "Surfactants Science Series" volume 34 ed. Richmond 1990, volume 37 ed. Rubingh 1991 and volume 53 eds. Cross and Singer 1994, Marcel Dekker Inc. New York" .

Any of the conventional types of such compounds may be used in the compositions of the present invention.

The fabric softening compounds are preferably compounds that provide excellent softening, and are characterised by a chain melting L/3 to La transition temperature greater than 250°C, preferably greater than 35O0C, most preferably greater than 450°C. This L/3 to Lo; transition can be measured by differential scanning calorimetry as defined in "Handbook of Lipid Bilayers", D Marsh, CRC Press, Boca Raton, Florida, 1990 (pages 137 and 337) .

Substantially water-insoluble fabric softening compounds are defined as fabric softening compounds having a solubility of less than 1 x 10 wt % in demineralised water at 20°C. Preferably the fabric softening compounds have a solubility -4 of less than 1 x 10 wt%, more preferably from less than 1

x lθ"8 to 1 x 10~6 wt%.

Especially preferred are cationic fabric softening compounds that are water-insoluble quaternary ammonium materials having two C12-22 alkyl or alkenyl groups connected to the molecule via at least one ester link, preferably two ester links. An especially preferred ester-linked quaternary ammonium material can be represented by the formula:

R5 I R5 N+ R7-T-R6 I (CH2)p-T-R6

wherein each R5 group is independently selected from Cl-4 alkyl or hydroxyalkyl groups or C2-4 alkenyl groups; each R6 group is independently selected from C8-28 alkyl or alkenyl groups; and wherein R7 is a linear or branched alkylene group of 1 to 5 carbon atoms, T is

and p is 0 or is an integer from 1 to 5.

Di (tallowoxyloxyethyl) dimethyl ammonium chloride and/or its hardened tallow analogue is an especially preferred compound of this formula.

A second preferred type of quaternary ammonium material can be represented by the formula:

0OC R6

(R5)3N+- (CH2)P CH

CH2OOCR6

wherein R5, p and R6 are as defined above.

A third preferred type of quaternary ammonium material are those derived from triethanolamine (hereinafter referred to as "TEA quats') as described in for example US 3915867 and represented by formula:

(TOCH2CH2) 3N+(R9)

wherein T is H or (R8-CO-) where R8 group is independently selected from C8-28 alkyl or alkenyl groups and R9 is Cl-4 alkyl or hydroxyalkyl groups or C2-4 alkenyl groups. For example N-methyl-N,N,N-triethanolamine ditallowester or di- hardened-tallowester quaternary ammonium chloride or methosulphate. Examples of commercially available TEA quats include Rewoquat WE18 and Rewoquat WE20, both partially unsaturated (ex. WITCO) , Tetranyl AOT-I, fully saturated (ex. KAO) and Stepantex VP 85, fully saturated (ex. Stepan) .

It is advantageous if the quaternary ammonium material is biologically biodegradable.

Preferred materials of this class such as 1,2-bis (hardened tallowoyloxy) -3-trimethylammonium propane chloride and their methods of preparation are, for example, described in US 4 137 180 (Lever Brothers Co) . Preferably these materials comprise small amounts of the corresponding monoester as described in US 4 137 180, for example, 1-hardened tallowoyloxy-2-hydroxy-3-trimethylammonium propane chloride.

Other useful cationic softening agents are alkyl pyridinium salts and substituted imidazoline species. Also useful are primary, secondary and tertiary amines and the condensation products of fatty acids with alkylpolyamines.

The compositions may alternatively or additionally contain water-soluble cationic fabric softeners, as described in GB 2 039 556B (Unilever) .

The compositions may comprise a cationic fabric softening compound and an oil, for example as disclosed in EP-A- 0829531. The compositions may alternatively or additionally contain nonionic fabric softening agents such as lanolin and derivatives thereof.

Lecithins and other phospholipids are also suitable softening compounds.

In fabric softening compositions nonionic stabilising agent may be present. Suitable nonionic stabilising agents may be present such as linear C8 to C22 alcohols alkoxylated with 10 to 20 moles of alkylene oxide, ClO to C20 alcohols, or mixtures thereof. Other stabilising agents include the deflocculating polymers as described in EP 0415698A2 and EP 0458599 Bl.

Advantageously the nonionic stabilising agent is a linear C8 to C22 alcohol alkoxylated with 10 to 20 moles of alkylene oxide. Preferably, the level of nonionic stabiliser is within the range from 0.1 to 10% by weight, more preferably from 0.5 to 5% by weight, most preferably from 1 to 4% by weight. The mole ratio of the quaternary ammonium compound and/or other cationic softening agent to the nonionic stabilising agent is suitably within the range from 40:1 to about 1:1, preferably within the range from 18:1 to about 3:1.

The composition can also contain fatty acids, for example C8 to C24 alkyl or alkenyl monocarboxylic acids or polymers thereof. Preferably saturated fatty acids are used, in particular, hardened tallow C16 to C18 fatty acids. Preferably the fatty acid is non-saponified, more preferably the fatty acid is free, for example oleic acid, lauric acid or tallow fatty acid. The level of fatty acid material is preferably more than 0.1% by weight, more preferably more than 0.2% by weight. Concentrated compositions may comprise from 0.5 to 20% by weight of fatty acid, more preferably 1% to 10% by weight. The weight ratio of quaternary ammonium material or other cationic softening agent to fatty acid material is preferably from 10:1 to 1:10.

It is also possible to include certain mono-alkyl cationic surfactants which can be used in main-wash compositions for fabrics . Cationic surfactants that may be used include quaternary ammonium salts of the general formula R1R2R3R4N+ X- wherein the R groups are long or short hydrocarbon chains, typically alkyl, hydroxyalkyl or ethoxylated alkyl groups, and X is a counter-ion (for example, compounds in which Rl is a C8-C22 alkyl group, preferably a C8-C10 or C12-C14 alkyl group, R2 is a methyl group, and R3 and R4, which may be the same or different, are methyl or hydroxyethyl groups) ; and cationic esters (for example, choline esters) .

The choice of surface-active compound (surfactant) , and the amount present, will depend on the intended use of the detergent composition. In fabric washing compositions, different surfactant systems may be chosen, as is well known to the skilled formulator, for handwashing products and for products intended for use in different types of washing machine. The total amount of surfactant present will also depend on the intended end use and may be as high as 60 wt%, for example, in a composition for washing fabrics by hand. In compositions for machine washing of fabrics, an amount of from 5 to 40 wt% is generally appropriate. Typically the compositions will comprise at least 2 wt% surfactant e.g. 2- 60%, preferably 15-40% most preferably 25-35%, by weight of the composition.

Detergent compositions suitable for use in most automatic fabric washing machines generally contain anionic non-soap surfactant, or non-ionic surfactant, or combinations of the two in any suitable ratio, optionally together with soap. The compositions of the invention, when used as main wash fabric washing compositions, will generally also contain one or more detergency builders. The total amount of detergency builder in the compositions will typically range from 5 to 80 wt%, preferably from 10 to 60 wt%, by weight of the compositions.

Inorganic builders that may be present include sodium carbonate, if desired in combination with a crystallisation seed for calcium carbonate, as disclosed in GB 1 437 950 (Unilever) ; crystalline and amorphous aluminosilicates, for example, zeolites as disclosed in GB 1 473 201 (Henkel) , amorphous aluminosilicates as disclosed in GB 1 473 202 (Henkel) and mixed crystalline/amorphous aluminosilicates as disclosed in GB 1 470 250 (Procter & Gamble) ; and layered silicates as disclosed in EP 164 514B (Hoechst) . Inorganic phosphate builders, for example, sodium orthophosphate, pyrophosphate and tripolyphosphate are also suitable for use with this invention.

The compositions of the invention preferably contain an alkali metal, preferably sodium, aluminosilicate builder. Sodium aluminosilicates may generally be incorporated in amounts of from 10 to 70% by weight (anhydrous basis) , preferably from 25 to 50 wt%.

The alkali metal aluminosilicate may be either crystalline or amorphous or mixtures thereof, having the general formula: 0.8-1.5 Na2O. Al2O3. 0.8-6 SiO2

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. Suitable crystalline sodium aluminosilicate ion-exchange detergency builders are described, for example, in GB 1 429 143 (Procter & Gamble) . The preferred sodium aluminosilicates of this type are the well-known commercially available zeolites A and X, and mixtures thereof.

The zeolite may be the commercially available zeolite 4A now widely used in laundry detergent powders. However, according to a preferred embodiment of the invention, the zeolite builder incorporated in the compositions of the invention is maximum aluminium zeolite P (zeolite MAP) as described and claimed in EP 384 070A (Unilever) . Zeolite MAP is defined as an alkali metal aluminosilicate of the zeolite P type having a silicon to aluminium weight ratio not exceeding 1.33, preferably within the range of from 0.90 to 1.33, and more preferably within the range of from 0.90 to 1.20.

Especially preferred is zeolite MAP having a silicon to aluminium weight ratio not exceeding 1.07, more preferably about 1.00. The calcium binding capacity of zeolite MAP is generally at least 150 mg CaO per g of anhydrous material.

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, carboxymethyloxy succinates, carboxymethyloxymalonates, dipicolinates, hydroxyethyliminodiacetates, alkyl- and alkenylmalonates and succinates; and sulphonated fatty acid salts. This list is not intended to be exhaustive.

Especially preferred 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. Compositions according to the invention may also suitably contain a bleach system. Fabric washing compositions may desirably contain 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 aπtount of from 0.1 to 35 wt%, preferably from 0.5 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 0.1 to 8 wt%, preferably from 0.5 to 5 wt%.

Preferred bleach precursors are peroxycarboxylic acid precursors, more especially peracetic acid precursors and pernoanoic acid precursors. Especially preferred bleach precursors suitable for use in the present invention are N,N,N' ,N1 , -tetracetyl ethylenediamine (TAED) and sodium nonanoyloxybenzene sulphonate (SNOBS) . The novel quaternary ammonium and phosphonium bleach precursors disclosed in US 4 751 015 and US 4 818 426 (Lever Brothers Company) and EP 402 971A (Unilever) , and the cationic bleach precursors disclosed in EP 284 292A and EP 303 520A (Kao) are also of interest .

The bleach system can be either supplemented with or replaced by a peroxyacid. Examples of such peracids can be found in US 4 686 063 and US 5 397 501 (Unilever) . A preferred example is the imido peroxycarboxylic class of peracids described in EP A 325 288, EP A 349 940, DE 382 3172 and EP 325 289. A particularly preferred example is phthalimido peroxy caproic acid (PAP) . Such peracids are suitably present at 0.1 - 12%, preferably 0.5 - 10%.

A bleach stabiliser (transition metal sequestrant) may also be present. Suitable bleach stabilisers include ethylenediamine tetra-acetate (EDTA) , the polyphosphonates such as Dequest (Trade Mark) and non-phosphate stabilisers such as EDDS (ethylene diamine di-succinic acid) . These bleach stabilisers are also useful for stain removal especially in products containing low levels of bleaching species or no bleaching species.

An especially preferred bleach system comprises a peroxy bleach compound (preferably sodium percarbonate optionally together with a bleach activator) , and a transition metal bleach catalyst as described and claimed in EP 458 397A, EP 458 398A and EP 509 787A • (Unilever) . The compositions according to the invention may also contain one or more enzyme (s) .

Suitable enzymes include the proteases, amylases, cellulases, oxidases, peroxidases and lipases usable for incorporation in detergent compositions. Preferred proteolytic enzymes (proteases) are, catalytically active protein materials which degrade or alter protein types of stains when present as in fabric stains in a hydrolysis reaction. They may be of any suitable origin, such as vegetable, animal, bacterial or yeast origin.

Proteolytic enzymes or proteases of various qualities and origins and having activity in various pH ranges of from 4-12 are available and can be used in the instant invention. Examples of suitable proteolytic enzymes are the subtilisins which are obtained from particular strains of B. Subtilis B. licheniformis, such as the commercially available subtilisins Maxatase (Trade Mark) , as supplied by Genencor International N.V. , Delft, Holland, and Alcalase (Trade Mark) , as supplied by Novozymes Industri A/S, Copenhagen, Denmark.

Particularly suitable is a protease obtained from a strain of Bacillus having maximum activity throughout the pH range of 8-12, being commercially available, e.g. from Novozymes Industri A/S under the registered trade-names Esperase (Trade Mark) and Savinase (Trade-Mark) . The preparation of these and analogous enzymes is described in GB 1 243 785. Other commercial proteases are Kazusase (Trade Mark obtainable from Showa-Denko of Japan) , Optimase (Trade Mark from Miles Kali-Chemie, Hannover, West Germany) , and Superase (Trade Mark obtainable from Pfizer of U.S.A.) .

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.

The compositions of the invention may contain alkali metal, preferably sodium carbonate, in order to increase detergency and ease processing. Sodium carbonate may suitably be present in amounts ranging from 1 to 60 wt%, preferably from 2 to 40 wt%. However, compositions containing little or no sodium carbonate are also within the scope of the invention.

Powder flow may be improved by the incorporation of a small amount of a powder structurant, for example, a fatty acid (or fatty acid soap) , a sugar, an acrylate or acrylate/maleate copolymer, or sodium silicate. One preferred powder structurant is fatty acid soap, suitably present in an amount of from 1 to 5 wt%.

Other materials that may be present in detergent compositions of the invention include sodium silicate; antiredeposition agents such as cellulosic polymers; soil release polymers; inorganic salts such as sodium sulphate; or lather boosters as appropriate; proteolytic and lipolytic enzymes; dyes; coloured speckles; fluorescers and decoupling polymers. This list is not intended to be exhaustive. However, many of these ingredients will be better delivered as benefit agent groups in materials produced according to the first aspect of the invention. The detergent composition when diluted in the wash liquor (during a typical wash cycle) will typically give a pH of the wash liquor from 7 to 10.5 for a main wash detergent.

Particulate detergent compositions are suitably prepared by spray-drying a slurry of compatible heat-insensitive ingredients, and then spraying on or post-dosing those ingredients unsuitable for processing via the slurry. The skilled detergent formulator will have no difficulty in deciding which ingredients should be included in the slurry and which should not.

Particulate detergent compositions of the invention preferably have a bulk density of at least 400 g/litre, more preferably at least 500 g/litre. Especially preferred compositions have bulk densities of at least 650 g/litre, more preferably at least 700 g/litre.

Such powders may be prepared either by post-tower densification of spray-dried powder, or by wholly non-tower methods such as dry mixing and granulation; in both cases a high-speed mixer/granulator may advantageously be used. Processes using high-speed mixer/granulators are disclosed, for example, in EP 340 013A, EP 367 339A, EP 390 251A and EP 420 317A (Unilever) .

Liquid detergent compositions can be prepared by admixing the essential and optional ingredients thereof in any desired order to provide compositions containing components in the requisite concentrations. Liquid compositions according to the present invention can also be in compact form which means it will contain a lower level of water compared to a conventional liquid detergent.

Product Forms

Product forms include powders, liquids, gels, tablets, any of which are optionally incorporated in a water-soluble or water dispersible sachet, powders are preferred. The means for manufacturing any of the product forms are well known in the art. If the polysaccharide-grafted polymer particles are to be incorporated in a powder (optionally the powder to be tableted) , and whether or not pre-emulsified, they are optionally included in a separate granular component, e.g. also containing a water soluble organic or inorganic material, or in encapsulated form.

Examples

The present invention will now be described with reference to the following non-limiting examples :-

In the following examples where percentages are mentioned, this is to be understood as percentage by weight.

Example 1 : Preparation of Granules

Casein sodium salt ex Sigma is dissolved in warm water. Then the double emulsion of CMA, containing extrasoft silicon oil, water, cellulose mono-acetate (CMA) , and Arlatone F127 non-ionic is added to the casein sodium salt solution and stirred to obtain a homogenous mix. Finally Sodium citrate (2aq) is added to the mix and stirred in.

The dilute dispersion thus obtained was spray dried after further dilution according to the table below. Two examples were produced using identical conditions, one used a citrate and caseinate structurant (Example 1) and the other only used caseinate as the structurant (Comparative example A) . In each case the ratio of structurant to oil was 1:1. The mixed structurant system used 35 parts of citrate to 65 parts of caseinate.

Example 1 and comparative example A were tested as follows:

Viscosity: was measured using a Physica rheometer MCR300. Method: plate-plate rheometer, 500 mum distance, 20 C, flow measurement increasing shear rate.

Drying: was measured using a Mettler Toledo LJ16 Moisture Analyser. Method: infra red balance, setting at 16O0C, sample weight used was 2.5 g.

Dispersion: Dispersion of the samples was measured using a Malvern 260OLBD optical laser.

Viscosity The viscosity drops after addition of citrate by a factor of at least 10. Drying time and Moisture Example 1 lost 90% of its water after 360 seconds, whereas the Comparative example A lost 90% of its water 50 seconds slower, i.e. after 410 sec.

A minimum of 1% citrate is needed to obtain the drying effect, the effect is further improved at 2%. Increasing to 10% shows a further slight improvement. Thus, although the maximum amount of sodium citrate that can be used is fixed by the maximum binder capacity for the granule, typically as high as 75%, or more usefully 50%, in practice the preferred range is 0.5% to 15%, preferably 1% to 10 %, most preferably 1.5% to 5%.

The differing levels of citrate influence the oil droplet size by "forcing" water out of the internal phase. Table 2 - Particle size of oil droplets measured with a Malvern

Surprisingly the use of the citrate reduces the particle size without destabilising the system which would cause the oil droplets to coalesce to form larger particles. The granules produced are found to have approximately 20% citrate contained therein.