WO2011020991A1

WO2011020991A1 - Granular hueing ingredient for fabric washing compositions

Info

Publication number: WO2011020991A1
Application number: PCT/GB2010/001539
Authority: WO
Inventors: Mark De Witte
Original assignee: Brunner Mond (Uk) Limited
Priority date: 2009-08-18
Filing date: 2010-08-13
Publication date: 2011-02-24
Also published as: GB0914437D0; WO2011020991A4

Abstract

A granular hueing ingredient suitable for incorporation into a granular fabric washing composition comprises a hueing agent, water, and inorganic carrier particles. The inorganic carrier particles comprise or consist of particles of a porous sodium carbonate, so that the ingredient comprises 60 % or more by weight of the particles of porous sodium carbonate, with at least 20 % by weight of the sodium carbonate in a monohydrate state. A process for preparing the granular ingredient involves blending the hueing agent, water and the inorganic carrier particles to form a premix and forming the premix into granules, wherein the inorganic carrier particles comprise particles of a porous sodium carbonate, and wherein at least 60 % by weight, preferably at least 80 % by weight of the porous sodium carbonate, is in the anhydrate state immediately prior to forming the premix. The granular hueing ingredient may be formed in a simple process without the need for binding agents, leading to rapid process changeover times and reduced risk of undesired spotting from the hueing agent on washed fabrics.

Description

Granular Hueinq Ingredient for Fabric Washing Compositions Field The invention relates to a granular hueing ingredient suitable for incorporation into powdered or granular fabric washing compositions, to processes for the production of the hueing ingredient and to use of the ingredient in granular fabric washing compositions. Background

The use of hueing agents, such as whitening agents or blueing agents, in fabric washing applications is well known in the prior art. As fabrics age, their colour tends to fade upon exposure to air, UV light and soil deposits. The purpose of hueing agents is to counteract this natural yellowing of fabrics by providing light emission or absorption so that the overall light emission appears to be of a white rather than a yellow colour.

It has already been suggested that active hueing substances should be added to fabric washing powders in the form of granules or particles. For instance, WO

2006/020162 discloses coloured particles comprising a hueing agent, a binder and a suspending agent.

Hueing agents suitable for use in fabric washing powders are set out in WO

2006/020162, as well as in WO 2008/091524.

Problems in the prior art relating to the incorporation of hueing agents into granular fabric washing compositions include a number of issues set out below. When a coloured hueing agent is incorporated as part of the overall composition of fabric washing composition granules, it may lead to an undesirable appearance for the composition. Incorporation of hueing agents in the form of adjunct or speckles may lead to staining of fabrics. This may arise where speckles containing relatively high levels of hueing agent are trapped against fabric for an extended period of time. In modern front-loading washing machines with reduced water usage, poor dissolution of fabric washing granules is a problem and unintended residues of granules may frequently occur. The presence of organic surfactants or binders in fabric washing compositions, which may form viscous mesophases (i.e. liquid crystalline phases) when wetted, can exacerbate such problems. Any adjuncts or speckles should be highly soluble but this may not be compatible with ensuring that an adjunct is not friable. Another problem is that the hueing agent may bleed out of the adjuncts or speckles containing it, into the rest of the fabric washing composition granules, leading to overall discolouration.

It is also important that hueing agent addition is compatible with the logistics in the fabric washing composition manufacturing process. Post-dosing of ingredients required at low levels into a fabric washing composition so that the ingredients are distributed homogeneously throughout the composition is desirable. For convenient factory handling of ingredients, they must be free-flowing, non-friable powders or granules and should not be prone to caking upon storage. In order to reduce raw material costs, it is desirable that easily sourced materials should be used as ingredients for adjuncts. It is also desirable that the ingredients may be easily manufactured with existing processing equipment, without the need for additional apparatus, hence the ability to be able to store ingredients for long periods after manufacture is highly desirable, so that the same apparatus may be used to manufacture different ingredients at different times. Contamination of process apparatus with binders and organic surfactant residues may make the apparatus difficult to wash down and clean. It is also desirable that such minor ingredient adjuncts remain evenly distributed throughout the composition during handling and transport to consumer outlets. This is to ensure that when a consumer takes an aliquot or dose of composition from a package, each aliquot contains approximately the correct amount of adjuncts.

Different granules within a granular fabric washing composition may have differing equilibrium RH values. Redistribution of moisture on storage can lead to

decomposition of bleach ingredients such as percarbonates or perborates, and may also lead to caking and poor powder flow of the composition. It is important that speckles or adjuncts are compatible with other ingredients of the composition.

When organic surfactants or binders are used to form granules, these are typically used in the form of aqueous pastes or slurries, and after granulation has been carried out, it is generally necessary to dry the resulting granules to remove excess water prior to storage and use in detergent compositions. It is desirable to form hueing granules without the need for a drying step. Furthermore, organic

surfactants or binders used in hueing granules may interact with the combination of surfactants selected for optimal detergency in a detergent composition. This may lead to a change in level of hueing agent requiring rebalancing of other components in a formulation. It is desirable to avoid such interactions between adjuncts and detergent systems.

Hence there is a need for granular hueing ingredients for fabric washing granular compositions which overcome or address some or all of the problems in the prior art.

Summary of the invention

One object of the invention, amongst others, is to provide a granular hueing ingredient for incorporation into granular fabric washing compositions which reduces risk of staining of fabrics and bleeding of the hueing agent into the composition. Furthermore, it is an object of the invention to provide a granular hueing ingredient which includes high levels of readily available raw materials in addition to the hueing agent itself. It is also an object of the invention to provide a granular hueing agent ingredient which is free-flowing, not prone to excessive caking and which is of similar density and particle size to conventional granular components of fabric washing compositions. It is a further object of the invention to provide a process for forming hueing granules which does not require a separate drying step after granulation, hence giving a simple process. Another object of the invention is to provide a process for forming granular hueing ingredients which may be carried out using conventional granulation apparatus with easy cleaning of the granulation apparatus after use.

Accordingly, a first aspect of the invention provides a granular hueing ingredient suitable for incorporation into a granular fabric washing composition, the ingredient comprising:

(i) a hueing agent,

(ii) water, and

(iii) inorganic carrier particles, wherein the inorganic carrier particles comprise particles of a porous sodium carbonate, wherein at least 20% by weight of the sodium carbonate is in a monohydrate state, and wherein the granular hueing agent comprises 60% or more by weight of the particles of porous sodium carbonate, expressed as anhydrous sodium carbonate.

A second aspect of the invention provides a process for the preparation of a granular hueing ingredient comprising the steps of:

(i) blending a hueing agent, water and inorganic carrier particles to form a premix and (ii) forming the premix into granules, wherein the inorganic carrier particles comprise particles of a porous sodium carbonate, whereby the resulting granular hueing agent comprises 60% or more by weight of the particles of porous sodium carbonate, expressed as anhydrous sodium carbonate and wherein at least 60% by weight, preferably at least 80% by weight of the porous sodium carbonate, is in the anhydrate state immediately prior to step (i).

A third aspect of the invention provides a granular hueing ingredient obtained or obtainable by the process of the second aspect of the invention.

A fourth aspect of the invention provides a granular fabric washing composition comprising a granular hueing ingredient according to the first or third aspects of the invention. A fifth aspect of the invention provides a method for incorporating a hueing agent into a granular fabric washing composition comprising providing a granular hueing ingredient according to the first or third aspects of the invention and blending the granular hueing ingredient into the granular fabric washing composition. A sixth aspect of the invention provides the use of a granular hueing ingredient according to the first or third aspects of the invention as an adjunct to provide a hueing agent in a granular fabric washing composition.

Detailed description

The following features, set out in detail in relation to the first aspect of the invention, or in relation to other aspects of the invention are applicable to all the various aspects of the invention where appropriate. When suitable, combinations of the following features may be employed as part of the various aspects of the invention, for instance as set out in the claims. The first aspect of the invention provides a granular hueing ingredient suitable for incorporation into a granular fabric washing composition, the ingredient comprising: a hueing agent, water, and inorganic carrier particles. The inorganic carrier particles may include different types of inorganic particles, but specifically comprise particles of a porous inorganic salt having first and second hydration states, the second hydration state having a higher water content than the first hydration state, and wherein at least 20% by weight of the inorganic salt is in the second hydration state. Specifically, the porous inorganic salt is a porous sodium carbonate, wherein the first hydration state is the anhydrate and the second hydration state is the

monohydrate.

Preferably, the porous sodium carbonate that is not in the monohydrate state is in an anhydrous state. Suitably, the particles of porous sodium carbonate have a median particle diameter, from 20 to 200 μm. This may be measured prior to incorporation into the granular hueing ingredient. Preferably, the median particle diameter is from 50 to 120 μ. Typically, this will be measured on the sodium carbonate prior to its incorporation into the granular hueing ingredient of the invention.

It is to be understood that the porous sodium carbonate particles referred to herein may themselves be formed from smaller crystalline structures having size from 0.1 to 50 μm. These smaller crystallites are generally known as primary particles.

Groups of such primary particles become agglomerated to form larger secondary particles of the inorganic porous salt. It is these secondary particles which are referred to as the particles of porous sodium carbonate and it is these secondary particles which have a median particle diameter from 20 to 200 μm as set out hereinbefore. The porosity of the secondary particles of porous sodium carbonate may arise from voids between the primary particles from which it is made up. In this specification, particle sizes are measured by sieving using standard ASTM sieves having sieve sizes separated by factors of 1.414. When calculating particle diameters, it is assumed that the diameter of particles on a particular sieve is the geometric mean of the mesh separation of that sieve and the mesh separation of the next larger sieve in the series. By "median" in this specification is meant the particle diameter where 50% by weight of particles have a diameter less than the median diameter and 50% by weight have a diameter larger than the median diameter. This is sometimes referred to in the art as d₅o or D5₀. The porous sodium carbonate suitably has a pore volume of from 0.2 to 1.0 cm³/g, such as 0.4 to 0.8 cm³/g. The median pore diameter is suitably from 3 to 20 μm, preferably 5 to 15 μm. Again this will typically be measured prior to the

incorporation of the sodium carbonate into the granular hueing ingredient. Pore volumes and diameters are suitably measured by standard mercury

porosimetry techniques, and refer to intra-particle pores only. This is achieved by discarding porosimetry data for inter-particle void spaces. For the material of interest, this will be achieved by discarding porosimetry data corresponding to pore sizes greater than 0.25 times the median particle diameter. The measurement is carried out on the secondary particles of porous inorganic salt. At very high mercury pressures, these may be broken down into their primary particles. Such data is also discarded.

The porous sodium carbonate is a salt soluble in water. Preferably, to avoid residues, any inorganic carrier particle is also soluble in water, having a solubility of at least 5g/100ml in water at 20⁰C, preferably at least 10g/100ml, more preferably at least 20g/100ml.

A suitable commercial source of the porous inorganic salt is known as light ash. Preferably, the granular hueing ingredient of the invention comprises less than 5%, preferably less than 1%, more preferably less than 0.5% and even more preferably less than 0.1% by weight of organic surfactant, binding agent or mixtures thereof. In other words, if both surfactant and binder are present in the granular hueing ingredient, the combined amount of surfactant and binder is preferably less than 5% by weight of the granular hueing ingredient.

Such components (i.e. organic surfactant or binding agent) in the granular ingredient of the invention are thought to lead to possible formation of viscous phases during dissolution of the ingredient in use, and this may give rise to adhesion to fabrics and spotting or staining. By "organic surfactant" is meant surfactants such as those commonly used in granular fabric washing products, such as anionic surfactants, non-ionic surfactants, cationic surfactants, zwitterionic surfactants, amphoteric surfactants.

Binders may gel at very high concentrations in aqueous detergent solutions, even though at low concentrations such as in the wash water they may substantially completely dissolve or disperse to enable the contents of the particle to be released in the wash water. Hence, the presence of binder, or binder combined with surfactant, in the granular hueing ingredient of the invention, is not preferred.

By binder is meant any binder material commonly used in the art. Typical binders include synthetic organic polymers such as polyethylene glycols,

polyvinylpyrrolidones, polyacetates, polymeric polycarboxylates such as water- soluble acrylate copolymers, cationic polymers such as ethoxylated hexamethylene diamine quaternary compounds, surfactants, liquid glucose, sugars and sugar alcohol such as sorbitol, manitol, Xylitol and mixtures thereof. It is to be noted that the term binders may also encompass organic surfactants as set out hereinbefore. Other examples of materials used as binders include Acacia, Alginic Acid,

Carbomer, Dextrin, Gelatin, Guar Gum, Hydrogenated vegetable oil type 1 , Magnesium aluminium silicate, Maltodextrin, Methylcellulose, polymethacrylates, povidone, sodium alginate, starch and zein, crosslinked, water-insoluble polymers such as crosslinked cellulose, water-swellable celluloses, crosslinked starch, crosslinked carboxymethyl cellulose, crosslinked carboxymethyl starch, crosslinked polyacrylates, and crosslinked polyvinyl pyrrolidones, anionic exchange resins such as those based on polyacrylate or sulfonate.

In other words, the granular hueing ingredient of the invention preferably consists essentially of (i) the hueing agent, (ii) water, and (iii) the inorganic carrier particles. Similarly, the inorganic carrier particles consist essentially of the porous sodium carbonate.

By "consist essentially" it is meant that the ingredients include only the listed components along with the normal impurities present in commercial materials and with any other additives present at levels which do not affect the operation of the invention, for instance at levels less than 5% by weight, typically less than 1% or even 0.5% by weight.

Suitably, the granular hueing ingredient of the invention will have a median diameter from 300 to 2000 μm, preferably from 350 to 1200 μm. This is in order for it to be compatible with the other granular components of granular fabric washing compositions so that the granular hueing ingredient of the invention does not tend to segregate out on packing and transport after incorporation into a granular fabric washing composition.

The density of the granular hueing ingredient (pouring, i.e. loose packed density) will typically be from 800 to 1100 kg/m³.

Typically, the granular hueing ingredient of the invention comprises from 1 to 10% by weight of hueing agent. Hueing agents are compounds which can alter the tint of a surface as they absorb at least a portion of the visible light spectrum. Suitable fabric hueing agents for use in the invention include dyes, dye-clay conjugates, and pigments. Dyes mat be soluble in water or insoluble. Suitable dyes include small molecule dyes and polymeric dyes. Suitable small molecule dyes include small molecule dyes selected from the group consisting of dyes falling into the Colour Index (C.I.) classifications of Direct Blue, Direct Red, Direct Violet, Acid Blue, Acid Red, Acid Violet, Basic Blue, Basic Violet and Basic Red, or mixtures thereof. Particularly useful small molecule dyes for use as hueing agents include small molecule dyes selected from the group consisting of Colour Index (Society of Dyers and Colourists, Bradford, UK) numbers Direct Violet 9, Direct Violet 35, Direct Violet 48, Direct Violet 51 , Direct Violet 66, Direct Blue 1 , Direct Blue 71 , Direct Blue 80, Direct Blue 279, Acid Red 17, Acid Red 73, Acid Red 88, Acid Red 150, Acid Violet 15, Acid Violet 17, Acid Violet 24, Acid Violet 43, Acid Red 52, Acid Violet 49, Acid Blue 15, Acid Blue 17, Acid Blue 25, Acid Blue 29, Acid Blue 40, Acid Blue 45, Acid Blue 75, Acid Blue 80, Acid Blue 83, Acid Blue 90 and Acid Blue 113, Acid Black 1 , Basic Violet 1 , Basic Violet 3, Basic Violet 4, Basic Violet 10, Basic Violet 35, Basic Blue 3, Basic Blue 16, Basic Blue 22, Basic Blue 47, Basic Blue 66, Basic Blue 75, Basic Blue 159 and mixtures thereof. Preferred are small molecule dyes selected from the group consisting of Colour Index (Society of Dyers and Colourists,

Bradford, UK) numbers Acid Violet 17, Direct Blue 71 , Direct Violet 51 , Direct Blue 1 , Acid Red 88, Acid Red 150, Acid Blue 29, Acid Blue 113 or mixtures thereof. Suitable polymeric dyes for use as hueing agents include polymeric dyes selected from the group consisting of polymers containing conjugated chromogens (dye- polymer conjugates) and polymers with chromogens co-polymerized into the backbone of the polymer and mixtures thereof. Particularly suitable polymeric dyes include polymeric dyes selected from the group consisting of fabric-substantive colorants sold under the name of Liquitint® (Milliken Chemical): dye-polymer conjugates formed from at least one reactive dye and a polymer selected from the group consisting of polymers comprising a moiety selected from the group consisting of a hydroxyl moiety, a primary amine moiety, a secondary amine moiety, a thiol moiety and mixtures thereof. In still another aspect, suitable polymeric dyes include polymeric dyes selected from the group consisting of Liquitint®(Milliken Chemical) Violet CT or Violet DD, carboxymethyl cellulose (CMC) conjugated with a reactive blue, reactive violet or reactive red dye such as CMC conjugated with C.I. Reactive Blue 19, sold by Megazyme, Wicklow, Ireland under the product name AZO-CM-CELLULOSE, product code S-ACMC,

alkoxylated triphenyl-methane polymeric colourants, alkoxylated thiophene polymeric colourants, and mixtures thereof.

Suitable dye clay conjugates include dye clay conjugates selected from the group comprising at least one cationic/basic dye and a smectite clay, and mixtures thereof. In another aspect, suitable dye clay conjugates include dye clay conjugates selected from the group consisting of one cationic/basic dye selected from the group consisting of C.I. Basic Yellow I through 108, C.I. Basic Orange 1 through 69, C.I. Basic Red 1 through 118, C.I. Basic Violet 1 through 51 , C.I. Basic Blue 1 through 164, C.I. Basic Green 1 through 14, C.I. Basic Brown 1 through 23, Cl Basic Black 1 through 11 , and a clay selected from the group consisting of

Montmorillonite clay, Hectorite clay, Saponite clay and mixtures thereof. In still another aspect, suitable dye clay conjugates include dye clay conjugates selected from the group consisting of: Montmorillonite Basic Blue B7 C.I. 42595 conjugate, Montmorillonite Basic Blue B9 C.I. 52015 conjugate, Montmorillonite Basic Violet V3 C.I. 42555 conjugate, Montmorillonite Basic Green G1 C.I. 42040 conjugate, Montmorillonite Basic Red R1 C.I. 45160 conjugate, Montmorillonite C.I. Basic Black 2 conjugate, Hectorite Basic Blue B7 C.I. 42595 conjugate, Hectorite Basic Blue B9 C.I. 52015 conjugate, Hectorite Basic Violet V3 C.I. 42555 conjugate, Hectorite Basic Green G1 C.I. 42040 conjugate, Hectorite Basic Red R1 C.I. 45160 conjugate, Hectorite C.I. Basic Black 2 conjugate, Saponite Basic Blue B7 C.I.

42595 conjugate, Saponite Basic Blue B9 C.I. 52015 conjugate, Saponite Basic Violet V3 C.I. 42555 conjugate, Saponite Basic Green G1 C.I. 42040 conjugate, Saponite Basic Red R1 C.I. 45160 conjugate, Saponite C.I. Basic Black 2 conjugate and mixtures thereof. Suitable pigments include pigments selected from the group consisting of flavanthrone, indanthrone, chlorinated indanthrone containing from 1 to 4 chlorine atoms, pyranthrone, dichloropyranthrone, monobromodichloropyranthrone, dibromodichloropyranthrone, tetrabromopyranthrone, perylene-3,4,9,10- tetracarboxylic acid diimide, wherein the imide groups may be unsubstituted or substituted by C1-C3-alkyl or a phenyl or heterocyclic radical, and wherein the phenyl and heterocyclic radicals may additionally carry substituents which do not confer solubility in water, anthrapyrimidinecarboxylic acid amides, violanthrone, isoviolanthrone, dioxazine pigments, copper phthalocyanine which may contain up to 2 chlorine atoms per molecule, polychloro-copper phthalocyanine or

polybromochloro-copper phthalocyanine containing up to 14 bromine atoms per molecule and mixtures thereof. In another aspect, suitable pigments include pigments selected from the group consisting of Ultramarine Blue (C.I. Pigment Blue 29), Ultramarine Violet (C.I. Pigment Violet 15) and mixtures thereof. The aforementioned fabric hueing agents can be used in combination (any mixture of fabric hueing agents can be used).

Suitable hueing agents are also described in detail in U.S. Patent publication No. 7,208,459 B2.

A particularly preferred hueing agents are dye-polymer conjugates formed from at least one reactive dye and a polymer such as Liquitint®Violet DD provided by Milliken Chemical. The granular hueing ingredient may typically have from 2 to 15%, preferably from 3 to 10%, more preferably from 3 to 6% by weight of water. The weight of water in the granules of the composition may be measured suitably by drying to constant weight in an oven at 45O⁰C. Hence, the amount of water specified here includes water of hydration bound into the chemical structure of the porous inorganic particles in addition to any free water present inside pores.

The granular hueing ingredient may suitably comprise from 60 to 97% by weight of porous sodium carbonate expressed as anhydrate by weight, for instance, 65%, 70%, 75% or even 80% or more, or 90% or more. There may be up to 96% by weight, or lower amounts such as to 90%, or up to 85% depending upon other formulation components present.

The second aspect of the invention provides a process for the preparation of a granular hueing ingredient comprising the steps of: (i) blending a hueing agent, water and inorganic carrier particles to form a premix, and (ii) forming the premix into granules, wherein the inorganic carrier particles comprise particles of a porous sodium carbonate, whereby the resulting granular hueing agent comprises 60% or more by weight of the particles of porous sodium carbonate, expressed as anhydrous sodium carbonate. At least 60% by weight, preferably at least 80% by weight, more preferably at least 95% by weight of the porous sodium carbonate is in the anhydrate state immediately prior to step (i). The % weight is expressed as % weight of porous sodium carbonate as anhydrate.

Preferably, the granulation of the premix takes place soon after the premix has been formed. Without wishing to be bound by any theory, it is thought that the hydration of the porous sodium carbonate may lead to recrystallisation of at least some of the salt from its first hydrate state (anhydrate) to its second hydrate state (monohydrate), causing interlocking crystals to form and grow, locking together the secondary particles of the salt into a bound granule. Hence it is preferable to form the granules from the premix before such recrystallisation has occurred. The operation of the granulation process of the invention suitably takes place below about 100⁰C as the monohydrate is unstable and loses water of hydration above this temperature. Preferably, granulation is effected below 8O⁰C, preferably below 65⁰C.

In a batch process, or in a continuous granulation process, the granulation step should take place within 24 hours of the start of formation of the premix to be granulated, preferably within 4 hours or even within 1 hour or within 10 minutes, whereby granule strength I improved.

As with any industrial granulation process, some material may be recycled back for reprocessing. Typically, the amount of recycled material to be used in the process should be limited to less than 30%, preferably less than 10% by weight of the total process stream in order to reduce loss in granule strength.

The premix may be prepared by any suitable process. For example, a solution or slurry of hueing agent and water may be prepared and sprayed onto the inorganic carrier particles in a fluid bed dryer/coater or into a mixing-container or mixer drum.

The premix may be formed into granules by for example an extrusion process, a fluid bed process, rotary atomization, agglomeration or a moulding process.

Preferably, the granules are formed by an agglomeration and/or extrusion process. The agglomeration and also the extrusion processes, provide a simple, fast, efficient, cost-effective means of preparing a granule, with the term granule herein including noodle, needle or shaped form of particles.

Formation of the premix (i) and the granulation step (ii) may also take place concurrently.

Suitable pieces of equipment in which to carry out the mixing and granulation of the present invention are mixers of Fukae type such as the Fukae® FS-G Series manufactured by Fukae Powtech Kogyo Co. Japan. This apparatus is essentially in the form of a bowl-shaped vessel accessible via a top port, provided near its base with a stirrer having substantially vertical axis, and a cutter positioned on a side wall. The stirrer and cutter may be operated independently of one another and at separately variable speeds. The vessel can be fitted with a heating or cooling jacket. Other similar mixers found to be suitable for use in the process of the invention include Diosna® V series ex Dierks & Sahne, Germany; and the Pharma Matrix® ex T K Fielder Ltd., England. Other mixers believed to be suitable for use in the process of the invention are the Fuji® VG-C series ex Fuji Sangyo Co., Japan; and the Roto® ex Zanchetta & Co SRL, Italy. Patterson-Kelly V- Blender, ribbon mixers, Sigma, Z-blade, Forberg mixers may also be suitable. High shear mixer-granulators for example as outlined below may be preferred although medium or low shear mixing and granulation may be equally suitable.

Other suitable equipment can include Eirich® Series R and RV, manufactured by Gustau Eirich Hardheim, Germany; Lόdige, Series FM for batch mixing or series CB and KM, either separately or in series for continuous mixing/agglomeration, manufactured by Lόdige Maschinenbau GmbH, Paderborn Germany; Drais® T 160 Series, manufactured by Drais Werke GmbH, Mannheim, Germany; and

Winkworth® RT 25 series, manufactured by Winkworth Machinery Ltd., Berkshire, England. Any suitable mixer with mixing and granulation capability and having a residence time in the order of 0.1 to 10 minutes can be used. The "turbine-type" impeller mixer, having several blades on an axis of rotation, is also suitable. The invention can be practiced as a batch or a continuous process. The granular hueing ingredient obtained by the processes set above is suitable for direct use, or may be treated by additional process steps such as the commonly used steps drying and or cooling, and/or dusting.

One preferred process for the invention involves the use of a roller

compactor/granulator apparatus such as the WP120 Pharma made by Alexander Wercke AG. Such apparatus forms a granule from a premix by first passing the premix through the gap of a roller mill to form a compacted sheet which is subsequently fragmented into granules by a nibbler or toothed cutter. Suitable granule sizes are obtained by passing or forcing the granules through screens, with granules which are too large or too small recycled back to the premix. Coarse material may be comminuted prior to recycling by means of, for instance, a hammer mill.

Another preferred process involves the use of a high shear mixer known as a recycler, for instance a Lόdige™Recycler, operating as part of a continuous process, where the inorganic carrier particles are fed in at one end of the recycler and a solution of the hueing agent is sprayed into the recycler. Rotating blades form the premix and granulate the premix into granules which emerge from the other end of the recycler. Once again, the granules may be classified using screens with fines and excessively coarse material returned to recycle. Coarse material may be comminuted prior to recycling by means of, for instance, a hammer mill.

A third aspect of the invention provides a granular hueing ingredient obtained or obtainable by the process of the second aspect of the invention. The fourth aspect of the invention provides a granular fabric washing composition comprising a granular hueing ingredient of the invention as set out hereinbefore.

Further aspects of the invention include a method for incorporating a hueing agent into a granular fabric washing composition comprising providing a granular hueing ingredient according to the invention and blending the granular hueing ingredient into the granular fabric washing composition.

Another aspect of the invention is the use of a granular hueing ingredient according to the invention as an adjunct to provide a hueing agent in a granular fabric washing composition. By "granular fabric washing composition" is meant a fabric washing composition in solid powder or granule form, typically containing detergent active compounds such as organic surfactants as set out hereinbefore. Such compositions generally also include detergency builders and may include other components such as bleaches, bleach activators, enzymes and the like.

The hueing granule ingredient of the invention is suitable for use with fabric washing compositions where the bulk of the composition has been made, for instance, by a mechanical granulation route (so-called high bulk density powders) or by a spray-drying route (so-called low or medium bulk density powders).

A fabric washing composition may comprise from 0.1 to 5%, preferably from 0.2 to 3% and most preferably from 0.5 to 2% by weight of the granular hueing ingredient. A fabric washing composition which suited to the incorporation of a granular hueing ingredient according to the invention will generally comprise one or more detergent active compounds which can be chosen from soap and non-soap anionic, cationic, nonionic, amphoteric or zwitterionic detergent active compounds, and mixtures thereof. Many suitable detergent-active compounds are commercially 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.

Bleaching materials which may be present include peroxy bleach compounds, such as inorganic persalts and organic peracids. Inorganic persalts can be used in combination with suitable transition metal catalysts or organic peracid precursors as activators for the persalt. Preferably, peroxy bleach compounds are employed together with an activator.

The inorganic persalt, acts to release active oxygen in solution, and the activator for use with the persalt is usually an organic compound having one or more reactive acyl residues, which cause the formation of peracids, the latter providing a more effective bleaching action at a low temperature, that is, in the range from 20 to 60 ⁰C, than is possible with the inorganic persalt itself.

Typical examples of suitable peroxy bleach compounds are inorganic persalts such as alkali metal perborates, i.e. tetrahydrates and/or monohydrates, alkali metal percarbonates, persilicates and perphosphates and mixtures thereof. Sodium percarbonate is the preferred inorganic persalt.

Detergency builders include soaps, inorganic and organic water-soluble builder salts, as well as various water-insoluble and so-called "seeded" builders, whose function is to soften hard water by solubilisation or by removal by other means (e.g. by sequestration, precipitation or ion exchange) of calcium and to a lesser extent magnesium salts responsible for water hardness, thereby improving detergency. Inorganic detergency builders include, for example, water-soluble salts of phosphates, pyrophosphates, orthophosphates, polyphosphates, phosphonates, and polyphosphonates. Specific examples of inorganic phosphate builders include sodium and potassium tripolyphosphates, phosphate and hexametaphosphates. Non-phosphorus-containing inorganic water-soluble sequestrants can also be selected for use as detergency builders. Specific examples of such non- phosphorus, inorganic builders include borate, silicate and aluminate salts. The alkali metal, especially sodium or potassium, salts are particularly preferred.

Organic non-phosphorus-containing, water-soluble detergency builders include, for example, the alkali metal, ammonium and substituted ammonium polyacetates, carboxylates, polycarboxylates, succinates, oxalates and polyhydroxysulphonates. Specific examples of the polyacetate and polycarboxylate builder salts include sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylenediamine tetraacetic acid, nitrilotriacetic acid, oxydisuccinic acid, mellitic acid, benzene polycarboxylic acids, citric acid, carboxymethyoxysuccinic acid, carboxymethyoxymalonic acid and mixtures thereof. Organic water-soluble non- phosphorus-containing builders include sodium citrate, sodium oxydisuccinate, sodium mellitate, sodium nitrilotriacetate, and sodium ethylenediaminetetraacetate. Other builders can include organic polymers such as polyacrylates, maleate, acetal carboxylates and copolymers. Other types of builder that can be used include various substantially water-insoluble materials which are capable of reducing the hardness content of laundering liquors by an ion-exchange process. Examples of such ion-exchange materials are the complex aluminosilicates, i.e. zeolite-type materials, which are useful pre-soaking or washing adjuncts which soften water by removal of calcium ion. Both the naturally occurring and synthetic "zeolites", especially Zeolite A and hydrated Zeolite A materials, are useful as builders.

Further ingredients which can optionally be employed in the detergent compositions of the invention include anti-redeposition agents such as sodium carboxymethyl- cellulose, polyvinyl pyrrolidone and the cellulose ethers such as methyl cellulose and ethyl hydroxyethyl cellulose; stabilisers such as ethylenediamine

tetramethylene phosphonate and diethylenetriamine pentamethylene phosphonate; fabric-softening agents; inorganic salts such as sodium and magnesium sulphate; and, usually present in small amounts, fluorescers, enzymes such as proteases and amylases, anti-caking agents, thickeners, germicides and colourants.

Various detergency enzymes well-known in the art for their ability to degrade and aid in the removal of various soils and stains can also optionally be employed in the compositions according to this invention. Detergency enzymes are commonly used at concentrations of from about 0.1 % to about 1.0% by weight of such

compositions. Typical enzymes include the various proteases, lipases, amylases, and mixtures thereof, which are designed to remove a variety of soils and stains from fabrics.

It may also be desirable to include one or more antideposition agents in the compositions of the invention, to decrease a tendency to form inorganic deposits on washed fabrics. The amount of any such antideposition agent when employed is normally from 0.1% to 5% by weight, preferably from 0.2% to 2.5% by weight of the composition. The preferred antideposition agents are anionic polyelectrolytes, especially polymeric aliphatic carboxylates, or organic phosphonates. It may also be desirable to include in the detergent compositions an amount of an alkali metal silicate, particularly sodium ortho-, meta- or preferably neutral or alkaline silicate. The presence of such alkali metal silicates at levels of at least 1%, and preferably from 5% to 15% by weight of the product, is advantageous in decreasing the corrosion of metal parts in washing machines, besides providing some measure of building and giving processing benefits and generally improved powder properties. The more highly alkaline ortho- and meta-silicates would normally only be used at lower amounts within this range, in admixture with the neutral or alkaline silicates. The detergent composition can be employed in a normal domestic or other laundry process conveniently employing a fabric washing machine. It is intended that the product is effective both in removing soil from fabrics being washed, and in optionally conferring other attributes such as bleaching, perfuming and fabric softening as appropriate.

For most purposes, the detergent composition can be employed at a concentration of 0.05 to 5% by weight of the wash liquor. Preferably, the concentration in the wash is from 0.2 to 2%, most preferably from 0.3 to 1.5% by weight of the wash liquor.

Specific embodiments of the present invention will now be described, by way of example only.

Example

This first example describes a granular hueing ingredient according to an embodiment of the invention containing light soda ash (anhydrous sodium carbonate) as porous sodium carbonate. In this Example, the inorganic carrier particles consist of the porous sodium carbonate (i.e. light ash). A solution was prepared of comprising 50% by weight of Liquitint Violet DD® hueing agent in water (i.e. 1:1 by weight hueing agent : water).

This was sprayed onto porous anhydrous sodium carbonate (light grade ash ) having a median particle size of 100 μm in a rotating blade mixer operating at low shear rates so that an un-granulated premix was formed.

The ingredient weights used to form the premix consisted of 100 parts light ash with 4 parts water and 4 parts hueing agent. The resulting premix was granulated using a roller compactor/granulator employing a roller pressure of 1200 psi (8.27 MPa) to yield a free-flowing granular hueing ingredient having 3.7% by weight hueing agent and having a median particle diameter of 848 μm. The pouring density of the resulting granular hueing ingredient was 957 kg/m³. The granules were violet in colour. Granulation was effected using materials initially at ambient temperature (about 25⁰C).

The following formulations are further examples suitable to give effective

granulation into hueing granules, for instance using the method set out for the first example above:

A 61% light ash, 8% hueing agent, 5% water, 26% sodium sulphate,

B 83% light ash, 4% hueing agent, 13% water,

C 90% light ash, 6.5% hueing agent, 3.5% water,

D 95% light ash, 1 % hueing agent, 4% water,

E 70% light ash, 10% hueing agent, 4% water, 16% sodium sulphate. For Examples A and E, commercial anhydrous sodium sulphate is suitable as additional inorganic carrier particle to be used alongside the light ash. Hueing agent is expressed as 100% hueing agent (Liquitint Violet DD®) by weight and sodium carbonate (light ash) as anhydrate.

It will be appreciated that numerous modifications to the above described

embodiment may be made without departing from the scope of the invention as defined in the appended claims. For example a continuous granulation apparatus such as a recycler may be used to perform premix formation and granulation concurrently.

The described and illustrated embodiment is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the scope of the inventions as defined in the claims are desired to be protected. It should be understood that while the use of words such as "preferable", "preferably", "preferred" or "more preferred" in the description suggest that a feature so described may be desirable, it may nevertheless not be necessary and

embodiments lacking such a feature may be contemplated as within the scope of the invention as defined in the appended claims. In relation to the claims, it is intended that when words such as "a," "an," "at least one," or "at least one portion" are used to preface a feature there is no intention to limit the claim to only one such feature unless specifically stated to the contrary in the claim. When the language "at least a portion" and/or "a portion" is used the item can include a portion and/or the entire item unless specifically stated to the contrary.

Claims

1. A granular hueing ingredient suitable for incorporation into a granular fabric washing composition, the ingredient comprising:

(i) a hueing agent,

(ii) water, and

(iii) inorganic carrier particles, wherein the inorganic carrier particles comprise particles of a porous sodium carbonate,

wherein at least 20% by weight of the sodium carbonate is in a monohydrate state, and

wherein the granular hueing agent comprises 60% or more by weight of the particles of porous sodium carbonate, expressed as anhydrous sodium carbonate.

2. A granular hueing agent according to claim 1 wherein the porous sodium carbonate that is not in the monohydrate state is in an anhydrous state.

3. A granular hueing ingredient according to claim 1 or claim 2 wherein the particles of porous sodium carbonate have a median particle diameter from 20 to

200 μm.

4. A granular hueing ingredient according to any preceding claim wherein the porous sodium carbonate has a pore volume of from 0.2 to 1.0 cm³/g.

5. A granular hueing ingredient according to any preceding claim wherein the porous sodium carbonate has a median pore diameter from 5 to 20 μm.

6. A granular hueing ingredient according to any preceding claim wherein the sodium carbonate is light ash.

7. A granular hueing ingredient according to any preceding claim which comprises less than 5%, preferably less than 1 %, more preferably less than 0.5% by weight of organic surfactant, binding agent or mixtures thereof.

8. A granular hueing ingredient according to any preceding claim which consists essentially of

(i) the hueing agent,

(ii) water, and

(iii) the inorganic carrier particles.

9. A granular hueing ingredient according to claim 8 wherein the inorganic carrier particles consist essentially of the porous sodium carbonate particles.

10. A granular hueing ingredient according to any preceding claim having a median diameter from 300 to 2000 μm, preferably from 350 to 1200 μm.

11. A granular hueing ingredient according to any preceding claim comprising from 1 to 10% by weight of hueing agent.

12. A granular hueing ingredient according to any preceding claim comprising from 60 to 96% by weight of inorganic porous salt expressed as anhydrous inorganic salt.

13. A process for the preparation of a granular hueing ingredient comprising the steps of:

(i) blending a hueing agent, water and inorganic carrier particles to form a premix and

(ii) forming the premix into granules, wherein the inorganic carrier particles comprise particles of a porous sodium carbonate, whereby the resulting granular hueing agent comprises 60% or more by weight of the particles of porous sodium carbonate, expressed as anhydrous sodium carbonate, and wherein at least 60% by weight, preferably at least 80% by weight of the porous sodium carbonate, is in the anhydrate state immediately prior to step (i).

14. A granular hueing ingredient obtained or obtainable by the process of claim 13.

15. A granular fabric washing composition comprising a granular hueing ingredient according to any one of claims 1 to 12 or claim 14.

16. A method for incorporating a hueing agent into a granular fabric washing composition comprising providing a granular hueing ingredient according to any one of claims 1 to 12 or claim 14 and blending the granular hueing ingredient into the granular fabric washing composition.

17. The use of a granular hueing ingredient according to any one of claims 1 to 12 or claim 14 as an adjunct to provide a hueing agent in a granular fabric washing composition.