Background of the invention Polymer-containing particles for use in aqueous and non- aqueous detergent compositions are well known. However, polymer-containing particles suitable for use in aqueous liquid detergent should meet different requirements than polymer-containing particles for use in non-aqueous liquid detergent compositions. Polymer-containing particles suitable for use in aqueous liquid detergent compositions should be stable therein i. e., the particles should be essentially insoluble in the composition. Furthermore, when the aqueous laundry liquid detergent composition with the polymer-containing particle are used in a laundering operation, they should not leave any residue on the laundered clothes. The polymer-containing particle should be at least dispersible and preferably soluble in the wash liquor, also at lower temperature, including room temperature. Furthermore, when dye or pigment is

incorporated in the particle the dye or pigment should not leach into the liquid detergent composition during storage.

Polymer-containing particles for use in liquid detergent products have been described before. GB-A-2 194 793 discloses particles of wax or gelatine. US-A-5 846 927 describes particles made from an emulsion of a wax and polyvinylalcohol-latex to protect enzymes encapsulated in the particle. US-A-4 946 624 discloses capsules containing perfume, wherein the capsule is made by a coacervation process from gelatine and a polyanionic material. However, in some circumstances gelatine and wax may leave residues on fabrics. Therefore, these materials are not preferred as particle material.

US-5 846 927 describes enzyme capsules comprising a hydrophobic polymer core and hydrocarbon oil. The complex structure of these capsules inherently makes the processing more expensive and more complicated. Therefore, there is a need for simple polymer-containing particle which is easy and inexpensive to prepare.

GB-1 461 775 discloses a liquid detergent with carrageenan particles. These particles have a simple structure but are not preferred because large scale preparation thereof is problematic. Another problem is that these particles cannot be flexibly used in any liquid detergent composition. This is because the composition should have a very good suspending capacity to prevent the particles from separating from the liquid. Carrageenan particles are usually prepared by dissolving carrageenan in water thereby producing a carrageenan solution. Heating the solution is preferred to dissolve the carrageenan completely. Then

droplets of the carrageenan solution can be made and contacted with a salt solution to harden said droplets to form carrageenan particles. However, relatively high concentrations of carrageenan, i. e. 0.2 % are needed in order for the droplets to solidify as particles when contacted with the hardening solution. Such concentrated carrageenan solutions tend to be rather viscous at room temperature making it difficult to process it without the need for expensive grinding steps or keeping the temperature elevated during the whole process. Furthermore, it has been noticed that the carrageenan solution and the carrageenan particles are prone to microbial degradation if they are stored at ambient temperatures without expensive preservatives.

Summary of the invention Surprisingly, it has now been found that one or more of the aforementioned problems can be overcome by formulating stable polymer-containing particles comprising a) more than 0.2% of a polymer selected from the group comprising kappa-carrageenan, iota-carrageenan, gellan gum, and mixtures thereof; b) more than 0.1% of a solid selected from the group consisting of silicates, carbonates, silicas, phosphates and mixtures thereof.

The present invention also encompasses a process to prepare the polymer-containing particles whereby the polymer solution remains mobile at room temperature and can be easily processed. Surprisingly, it has been found that

adding more than 0.1% of a solid to the carrageenan solution delays or prevents the solidification of said solution at room temperature making it easier to process the polymer solution.

The inventive process to prepare a polymer-containing particle suitable for use in an aqueous liquid detergent comprises the steps of: a) dissolving more than 0.1% polymer selected from the group comprising carrageenan and gellan gum and mixtures thereof, in water, preferably of more than 40°C thereby forming a polymer solution; b) adding more than 0.1% of a solid selected from the group consisting of aluminium silicates, carbonates, silicas, phosphates and mixtures thereof; c) optionally adding an effective amount of dye material; d) producing droplets of the solution; and e) contacting said droplets with a curing solution.

Detailed description of the invention The carrageenan particles described in GB-1 461 775 are difficult to process because the carrageenan solution tends to become too viscous too form droplets of the appropriate size. Unexpectedly, we have now found that the incorporation of a solid prevents this increase in viscosity. The solid can be any inorganic salt.

Furthermore, particles described in GB-1 461 775 can only be used in liquid detergent compositions with a relatively rigid structure to maintain the particles suspended. We have surprisingly found that incorporating zeolite and

carbonate salt in the carrageenan solution, the formed particles have a higher density and can be suspended in a wider range of compositions.

In addition, the carrageenan particles disclosed in GB-1 461 775 tend to be prone to microbial degradation if they are stored at ambient temperatures without expensive preservatives. Unexpectedly, we have now found that this problem can be overcome by increasing the pH to higher than 7.5 during the preparation and/or storage of the particles.

Thus, in another aspect the invention encompasses process of to prepare the inventive particle whereby the polymer solution has a pH of higher than 7.5 prior to contact with the curing solution.

Furthermore, we noticed that an important problem in large scale processing of carrageenan is the variability of strength of the formed gel. It is known that the strength of the gel can be influenced by the salt concentration of the curing solution. The strength of the gel is important because when this is too low the particles are not stable in the liquid detergent composition. We have now found that the weight average molecular weight of the carrageenan is an important factor. Preferably, the carrageenan is a kappa-carrageenan. It is also possible to use mixtures of kappa-carrageenan and iota-or lambda-carrageenan.

Preferably, the particle according the invention comprises less than 0.5% of gelatine, wax or petrolatum.

Polymer-containing particle The polymer-containing particle preferably has a particle diameter in the range of 300 to 5000 microns, more

preferably 500 to 2500 microns, and most preferably 700 to 2000. The density should preferably be in the range of 0.8 to 3 g/cm3, more preferably in the range of 0.9 to 1.8 g/cm3, and most preferably in the range of 0.95 to 1.20 g/cm3.

The amount of polymer-containing particles added to the liquid detergent composition is less than 50%, preferably less than 15%, more preferably less than 9% and more than 0.01%, preferably more than 0.1%, more preferably more than 0.3%. These percentages are calculated by using the weight of the polymer-containing particles prior to the addition and the weight of total composition after addition.

Polymer One polymer which may be used, for example, is carrageenan, especially kappa carrageenan. Kappa carrageenans are a class of polysaccharides which occur in some other red seaweed species. They are linear polysaccharides made up from alternating beta-1,3-and alpha-1,4-linked galactose residues. The 1,4-linked residues are the D- enantiomer and sometimes occur as the 3,6-anhydride. Many of the galactose resides are sulfated.

A number of carrageenan structures have been described and commercial materials are available which approximate to the ideal structures. However, variations between these structures occur, depending on the source of the carrageenan and the treatment of it after extraction.

A description of different carrageenan types is given in "Carrageenans"by Norman F. Stanley which is Chapter 3 of "Food Gels"edited by Peter Harris. Kappa carrageenan is sulfated on the 1,3-linked galactose residues, but not on the 1,4-linked resides. Iota carrageenan is sulfated on both residues. Lambda carrageenan has two sulfate groups on the 1,4-linked residues and one sulfate group on 70% of the 1,3-linked residues.

Other types of carrageenan may be used in mixtures with kappa. Aqueous solutions of iota carrageenan exist as reversible gels, but these are self healing. Iota carrageenan can be used to form compositions in accordance with this invention, but the compositions become lumpy during storage because of the self-healing property of iota carrageenan gels. Therefore, for this invention it is preferred to use kappa carrageenan or mixtures of kappa and iota.

Lambda carrageenan on its own in aqueous solution does not form gels because its higher charge density inhibits association between molecules and consequent structuring in liquids. However, some lambda carrageenan may be included in mixtures with kappa, or may be present as an impurity in commercial supplies of kappa or iota carrageenan.

If lambda carrageenan is included in a mixture of carrageenans, the mixture may contain a majority (more than half of the polysaccharide) of kappa or kappa and iota

carrageenan with a minority proportion of lambda carrageenan.

A polymer/gum of bacterial origin which also may be used is gellan. It is the polymer of a tetrasaccharide repeat unit, containing glucose, glucurronic acid, glucose and rhamrose residues. There is some substitution with acyl groups but these are often removed during production to give a low acyl gellan. Gellans are the subject of Chapter 6 by G. R.

Saunderson in"Food Gels"mentioned above.

Another possibility is to use a so-called synergistic gel which relies on the interaction of two polymer types. In general these may be formed from a polysaccharide, which is a glucomannan with sequences of mannose residue in its polymer chain, such as locust bean gum or guar gum, and a second polymer, for example, is carrageenan.

The polymer is selected from carrageenan, gellan gum, and mixtures thereof. Especially suitable polymers have a weight average molecular weight of at most 500,000 dalton.

Preferably the carrageenan is selected from the group including of kappa and iota carrageenan and mixtures thereof. Especially preferred particles are those wherein at least one polymer is a kappa carrageenan.

The polymer-containing particle comprises less than 15%, preferably less than 7.5%, more preferably less than 5% and more than 0.01% of the polymer, preferably more than 0.1%, more preferably more than 0.3%.

Solid Preferably the solid is selected from the group comprising silicates, carbonates, silicas, phosphates and mixtures thereof. The silicate may be a aluminium or a magnesium silicate. Especially preferred are aluminium silicate and calcium carbonate. Especially preferred is aluminium silicate. Examples are the different types Zeolite.

The solid should have a particle diameter of less than 200 micron, preferably less than 100 micron, more preferably less than 50 micron and a diameter of more than 0.01 micron, preferably more than 0.1 micron, more preferably more than 0.5 micron. The particle comprises less than 50%, preferably less than 7.5%, more preferably less than 5% and more than 0.01% of the solid, preferably more than 0.1%, more preferably more than 0.3%, even more preferably more than 2%. These percentages are by weight of the particle prior to addition of the particles to the liquid detergent.

Dye material For the purpose of the present invention the term dye material also covers pigment material.

The dye material is selected from the group including red, orange, yellow, green, blue dyes and mixtures thereof such as pink. More preferably dyes are selected that have a colour selected from blue, green and pink.

Preferably the dye is chemically and physically stable in association with the polymer material in the aqueous liquid

and preferably the dye does not cause spotting on articles in the wash cycle.

Dye material from any of the established dye classes can be selected. Preferably the dye is selected from Disperse, Acid, Reactive, Direct, Sulphur, VAT and Azo type dyes.

Pigments can be applied in a similar manner. Examples of Disperse dyes are Dispersed Blue 69-0007 ex BASF (CI pigment Blue 15: 1 CI constitution number 74160) and Patent Blue V80 (CI 42051). A especially preferred material is Monastral Blue dye.

Preferably the dye material is included in the polymer- containing particle in an effective amount to give the particle the desired colour. Preferably an effective amount is at levels of at least 10-6% by weight of the composition, more preferably at least 10-4% by weight of the composition, most preferably at least 10-2% by weight of the composition. Preferably the level is at most 2% by weight of the composition, more preferably at most 1% by weight of the composition, more preferably at most 0.75% by weight of the composition. The dye material can for example be included in levels of 0.0075% or of 0.025% by weight of the particle composition. For the dye material the percentages are by weight of the particle composition.

Detergent additive Optionally, at least one other detergent additive can be included in the inventive particle. Any compound suitable for use in detergent compositions may be included.

Additives which are simply more desirably released later in the wash (e. g., perfumes, fabric softening agents or anti- foams) can be included and controllably released, for example, by dilution of a concentrated liquid.

Other additives, such as anti-redeposition agent CP-5 polymer are not dissoluble in isotropic heavy duty liquid detergent compositions. These fine, insoluble particles cause the opaqueness of products. To prevent the opaqueness, these fine particle components can be included in the inventive particles.

Liquid detergent additives that are immiscible with liquid detergent compositions, such as amino silicone and silicone defoamer can be included in the inventive particles.

Functional polymers including color protecting polymers, fabric protection polymers and soil release polymers, such as PVP (polyvinylpyrrolidone), Narlex DC-1 ex National Starch (e. g., polyacrylate/methacrylate copolymer) and that can be salted out due to the high electrolyte concentration in liquid detergent compositions also can be incorporated in the polymer-containing particle.

In particular, it is desirable to include one or more enzymes since enzymes are highly efficient laundry washing ingredients used to promote removal of soils and stains during the cleaning process. Furthermore, it is also desirable to incorporate bleach and enzymes separately to further enhance detergent efficacies.

Process The process according the invention comprises the following steps: a) dissolving more than 0.1% polymer selected from the group comprising carrageenan and gellan gum and mixtures thereof, in water, preferably of more than 40°C thereby forming a polymer solution; b) adding more than 0.1% of a solid selected from the group consisting of silicates, carbonates, silicas, phosphates and mixtures thereof; c) optionally adding an effective amount of dye material; d) producing droplets of the solution ; and e) contacting said droplets with a curing solution.

For step a) it is preferred that the water temperature is less than 90°C, preferably less than 80°C, more preferably less than 70°C and more than 40°C of the solid, preferably more than 50°C, more preferably more than 55°C.

Preferably, the solid is added after the polymer had dissolved completely.

Droplets can be produced by any way known in the art.

Preferably the droplets are produced by spraying the carrageenan solution through a nozzle thereby forming droplets of an appropriate size.

The curing solution comprises less than 50%, preferably less than 15%, more preferably less than 6% of a salt and more than 0.01%, preferably more than 0.1%, more preferably more than 0.3% of a salt. Preferably, the salt contains a

cation selected from the group including K+, Rb+, Cs+, and Ca2+.

In a preferred process to prepare the inventive particle the pH is higher than 7.5 during the preparation and/or storage of the particles to minimise and/or block mould growth during storage. Preferably, the pH of the polymer solution is higher than 7.5 prior to hardening.

Alternatively, the particles may be stored at a pH higher than 7.5 after hardening. Thus in another aspect, the invention encompasses a process to prepare a polymer- containing particle comprising the steps of increasing the pH of the polymer solution prior to hardening to a pH of higher than 7.5 and/or storing the particles after hardening at a pH higher than 7.5. More preferably, the pH is higher than 8, most preferably higher than 8. 5.

Preferably, the pH is lower than 14, more preferably lower than 13, most preferably lower than 12. The pH may be adjusted by a adding any alkaline material compatible with the polymer. The alkaline material can be a alkali metal hydroxide but also a silicate or carbonate. Preferably, the alkaline material is an alkaline solid e. g. aluminium silicate or calcium carbonate.

Aqueous liquid detergent composition There are two general and separate classes of liquid detergent compositions, isotropic and structured liquids.

Isotropic liquids are liquids in which all ingredients are dissolved and, contrary to structured liquids, there is no structure present in isotropic liquid.

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

Externally structured liquids may provide a high viscosity upon storage.

In general, the degree of ordering of surfactant containing systems increases with increasing surfactant and/or electrolyte concentrations. At very low concentrations of surfactant and/or electrolyte, the surfactant can exist as a molecular solution, or as a solution of spherical micelles, both of these solutions being isotropic, i. e. they are not structured. With the addition of further surfactant and/or electrolyte structures of surfactant material may form. Various forms of such structures exists, e. g. bi-layers. They are referred to by various terms such as rod-micelles, anisotropic surfactant phase, planar lamellar structures, lamellar droplets and liquid crystalline phases. Various examples of liquids, which are internally structured with surfactant material, are given

in H. A. Barnes,"Detergents", Ch. 2. in K. Walters (Ed), "Rheometry: Industrial Applications", J. Wiley & Sons, Letchworth 1980. Often different workers have used different terminology to refer to the structures which are really the same. For instance, in European patent specification EP-A-0151884, lamellar droplets are called spherulites.

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

Preferably, the detergent composition according the invention is externally or internally structured. Even more preferred are lamellar-structured compositions.

Especially preferred are transparent/translucent liquid detergent compositions with at least about 50% transmittance of light using 1 centimeter cuvette at a wavelength of 410-800 nm, preferably 570-690 nanometers, wherein the composition is measured in absence of dies.

Alternatively, transparency of the composition may be measured as having an absorbency in the visible light wavelength (about 410 to 800 nm) of less than 0.3 which is in turn equivalent to at least 50% transmittance using cuvette and wavelength noted above. For purposes of the invention, as long as one wavelength in the visible light range has greater than 50% transmittance, it is considered to be transparent/translucent.

The liquid detergent composition comprises from 5-50% surfactant selected from the group comprising anionic, cationic, nonionic, amphoteric surfactants and mixtures thereof. Preferably, the liquid detergent composition comprises 1-40% a builder suitable for such compositions. Preferably, the builder is selected from the group comprising zeolites, sodium tripolyphosphate, citrate and organic polymers. Optionally, the liquid detergent composition may comprise an enzyme, a bleach, a perfume, a brightener, a sequestrant, a thickener, electrolyte, a hydrotrope, organic solvent, soil release polymer, anti dye transfer agents and other detergent additives common in the art.

Definitions All percentages used herein are expressed as percentages by weight unless otherwise indicated. All documents are incorporated herein by reference.

Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material, pH, temperatures etc., ought to be understood as modified by the word"about".

Where the term comprising is used in the specification or claims, it is not intended to exclude any terms, steps or features not specifically recited.

For the purpose of the present invention any reference to average particle diameter refers to the D (4,3) particle size, which is a volume-weighted mean diameter as described by M. Alderliesten, Part. Part. Cyst. Charact. 8, (1991) 237-241., unless explicitly stated to the contrary. The particle size can for example be determined with a Malvern Mastersizer and preferably by using a sweep sieve.

As used herein the term"stable particle"refers to particles of which more than 70% do not dissolve or disperse when stored in a liquid detergent composition for 12 weeks at 37°C wherein said liquid detergent composition comprises 10% surfactant, 10% builder.

As used herein the term"liquid detergent composition" encompasses both liquid and more viscous or gel like compositions. The term refers to a liquid detergent composition with a viscosity of less than 5000 mPAS, preferably less than 3000 mPAS, more preferably less than 2000 mPAS and a viscosity of more than 20 mPAS, preferably more than 100 mPAS, more preferably more than 500 mPAS when measured at a shear rate 21-S at 25°C. The term aqueous refers to composition comprising more than 5%, preferably more than 10%, more preferably more than 25% water and preferably less than 95% water.

EXAMPLES Examples A-D-Preparation of Suspended Capsules Several types of capsules were prepared in the lab to use for suspending and storage studies. The composition variations are shown in Table 1.

Table 1 Raws ExampleB,ExampleA, D, g g g g Deionized 2820. 00 98. 00 32. 20 29.40 water K-carrageenan 60. 00 2. 00 0. 80 0.60 gum Zeolite 90. 00 0. 00 4. 00 2.00 white pigment 30.00 0.00 0. 00 0.00 30% PVP 0. 00 40. 00 40. 00 20.00 solution Fluorescent 0.00 1.00 0. 00 0.00 dye

PVP = polyvinyl pyrrolidone Specifically, Kappa-carrageenan gum powder and water were mixed and heated to 160°F until the gum was well dispersed and hydrated. Other ingredients were added according to the list of Table 1 and mixing was continued until the ingredients were well mixed. The composition was cooled to room temperature for spraying through a two-fluid nozzle into a 5k KCl hardening solution bath. Capsules were collected and passed through screens of 500 and 2000 microns.

Example E-Preparation of Suspended Capsules Capsules using gellan gum were also prepared by: a) mixing 1000 g of deionized water, 5 g of Kelcogel LT (gellan gum Ex Monsanto) and 1.5 g of sodium citrate; b)

mixing and heating to 180°F for 30 minutes; c) turning off heat and mixing in 10 g pigment; d) letting cool to room temperature; and e) spraying through two-fluid nozzle into 10% NaCl hardening solution.

Particles Example E Raws Kelcogel Water sodium Pigmen LT citrate t g 5 1000 1. 5 10 Hardening solution Raws NaCl Water g 200 1800 Other functional ingredients were added to the gellan capsules similar to ingredients added to kappa-carrageenan capsules of Examples A-D. Other examples of ingredients which can be added to the capsules include PVP, fluorescent dye and silicone oil.