EP2627576B1

EP2627576B1 - Packaged concentrated particulate detergent composition

Info

Publication number: EP2627576B1
Application number: EP11752244.1A
Authority: EP
Inventors: Stephen Norman Batchelor; Andrew Paul Chapple; Stephen Thomas Keningley
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 2010-10-14
Filing date: 2011-09-07
Publication date: 2017-11-08
Anticipated expiration: 2031-09-07
Also published as: BR112013008954A2; ES2655979T3; CN103180222B; BR112013009125A2; BR112013009125B1; WO2012048956A1; CN103180222A; ZA201301715B; EP2627576A1; IN2013MN00624A

Description

This invention relates to a packaged concentrated particulate detergent composition with high visual appeal. In particular it relates to a product used at low dosage levels, for example less than 40g dose per wash. In particular it relates to concentrated particulate detergent compositions formed by extrusion and coating, particularly to those formed by extrusion of a dried surfactant blend, cutting of the extrudates into particles having a diameter of at least twice their thickness and coating the particles so formed by spraying on of an aqueous solution of an inorganic salt in a fluid bed and drying to form a hard shell.
Compact or concentrated compositions offer the advantage that pack size is reduced which is environmentally desirable. However shelf-impact at point-of-sale retail outlets e.g. on crowded shelves in supermarkets, may also be reduced as a result of the small product size. Visual appeal can be improved by enlarging the packaging, but this counter productive from an environmental point of view.
EP2166077A1 discloses a particle for use in a composition comprising a first coating layer comprising a coating material selected from a surfactant, surfactant precursor, builder, film-forming polymer and mixtures thereof, and a core, at least a portion of said core being coated by said coating wherein the particle additionally comprises a hueing dye.
It is an object of the present invention to provide a packaged concentrated particulate detergent composition which has visual appeal and yet storage stability in so far as visual features are concerned.
According to the present invention there is provided a packaged particulate detergent composition contained in a package according to claim 1.
With the above arrangement, the particulate product is coloured but the colourant, the dye, has greater photostability versus visible light, and can be stored in transparent packaging thereby improving the stability of the very feature providing shelf standout.

TRANSPARENT PACKAGING

In so far as the packaging is concerned, "transparent" means that its light transmittance is greater than 25% at wavelength of about 410-800 nm.
The transparent layer of the package according to the invention preferably has a transmittance of more than 25%, more preferably more than 30%, more preferably more than 40%, more preferably more than 50% in the visible part of the spectrum (approx. 410-800 nm).
Alternatively, absorbency of transparent layer may be measured as less than 0.6 (approximately equivalent to 25% transmitting) or by having transmittance greater than 25% wherein % transmittance equals: $\frac{1}{10^{absorbancy}} \times 100 %$
Conversely, absorbency of the opaque layer may be measured as more than 0.6. For purposes of the invention, as long as one wavelength in the visible light range has greater than 25% transmittance, the container is considered to be transparent.
All percentages, unless indicated otherwise, are intended to be percentages by weight.
Suitable materials for the transparent inner layer of the package include, but are not limited to: polypropylene (PP), polyethylene (PE), polycarbonate (PC), polyamides (PA) and/or polyethylene terephthalate (PETE), polyvinylchloride (PVC); and polystyrene (PS). The container may formed by extrusion, moulding e.g. blow moulding from a preform or by thermoforming or by injection moulding. Alternatively, absorbency of bottle may be measured as less than 0.6 (approximately equivalent to 25% transmitting) or by having transmittance greater than 25% wherein % transmittance equals: 1 10^absorbancy x 100% and corresponding absorbency levels for the remaining preferred levels above.

DYE

The dye is added to the surfactant mix in the core, preferably the dye is dissolved in the surfactant before the core is formed.
Dyes are described in Industrial Dyes edited by K. Hunger 2003 Wiley-VCH ISBN 3-527-30426-6.
Dyes for use in the current invention are selected from anionic and non-ionic dyes Anionic dyes are negatively charged in an aqueous medium at pH 7. Examples of anionic dyes are found in the classes of acid and direct dyes in the Color Index (Society of Dyers and Colourists and American Association of Textile Chemists and Colorists). Anionic dyes preferably contain at least one sulphonate or carboxylate groups. Non-ionic dyes are uncharged in an aqueous medium at pH 7, examples are found in the class of disperse dyes in the Color Index.
The dyes may be alkoxylated. Alkoxylated dyes are preferably of the following generic form: Dye-NR₁R₂. The NR₁R₂ group is attached to an aromatic ring of the dye. R₁ and R₂ are independently selected from polyoxyalkylene chains having 2 or more repeating units and preferably having 2 to 20 repeating units. Examples of polyoxyalkylene chains include ethylene oxide, propylene oxide, glycidol oxide, butylene oxide and mixtures thereof.
A preferred polyoxyalkylene chain is [(CH₂CR₃HO)_x(CH₂CR₄HO)_yR₅) in which x+y ≤ 5 wherein y ≥ 1 and z = 0 to 5, R₃ is selected from: H; CH₃; CH₂O(CH₂CH₂O)_zH and mixtures thereof; R₄ is selected from: H; CH₂O(CH₂CH₂O)_zH and mixtures thereof; and, R₅ is selected from: H; and, CH₃
A preferred alkoxylated dye for use in the invention is:
Preferably the dye is selected from acid dyes; disperse dyes and alkoxylated dyes.
Most preferably the dye is a non-ionic dye.
Preferably the dye is selected from those having: anthraquinone; mono-azo; bis-azo; xanthene; phthalocyanine; and, phenazine chromophores. More preferably the dye is selected from those having: anthraquinone and, mono-azo chromophores.
The dye is added to the coating slurry and agitated before applying to the core of the particle. Application may be by any suitable method, preferably spraying on to the core particle as detailed above.
The dye may be any colour, preferable the dye is blue, violet, green or red. Most preferably the dye is blue or violet.
Preferably the dye is selected from: acid blue 80, acid blue 62, acid violet 43, acid green 25, direct blue 86, acid blue 59, acid blue 98, direct violet 9, direct violet 99, direct violet 35, direct violet 51, acid violet 50, acid yellow 3, acid red 94, acid red 51, acid red 95, acid red 92, acid red 98, acid red 87, acid yellow 73, acid red 50, acid violet 9, acid red 52, food black 1, food black 2, acid red 163, acid black 1, acid orange 24, acid yellow 23, acid yellow 40, acid yellow 11, acid red 180, acid red 155, acid red 1, acid red 33, acid red 41, acid red 19, acid orange 10, acid red 27, acid red 26, acid orange 20, acid orange 6, sulphonated Al and Zn phthalocyanines, solvent violet 13, disperse violet 26, disperse violet 28, solvent green 3, solvent blue 63, disperse blue 56, disperse violet 27, solvent yellow 33, disperse blue 79:1.
The dye is preferably a shading dye for imparting a perception of whiteness to a textile.
The dye may be covalently bound to polymeric species.
A combination of dyes may be used.
Each particle has perpendicular dimensions x, y and z, wherein x is from 0.2 to 2 mm, y is from 2.5 to 8 mm (preferably 3 to 8 mm), and z is from 2.5 to 8 mm (preferably 3 to 8 mm).
The amount of coating on each coated particle is advantageously from 10 to 45, more preferably 20 to 35% by weight of the particles.
The number percentage of the packaged composition of particles comprising the core and coating is preferably at least 85%.
The coated particles preferably comprise from 0.001 to 3 wt % perfume.
The core of the coated particles preferably comprises less than 5 wt%, even more preferably less than 2.5 wt% inorganic materials.
The coating is preferably sodium carbonate, optionally in admixture with a minor amount of SCMC and further optionally in admixture with one or more of sodium silicate, water soluble fluorescer, water soluble or dispersible shading dye and pigment or coloured dye.
The particles are desirably oblate spheroids with diameter of 3 to 6 mm and thickness of 1 to 2 mm.
At least some, and preferably a major portion by number of the particles may be coloured other than white, as this can enhance the coloured particles. Multicoloured, e.g. some blue and some white, particles have also been found to provide even higher visual definition for the optimum control of dose.
It may be provided with a handle and /or a dose measuring device, or scoop. The measuring device may be a cap. Most preferably, it is a screw cap as that provides for more reliable protection against ingress of large amounts of water due to the cap being incorrectly replaced in use.

Manufacturing

The composition may be manufactured according to the process described in PCT/EP2010/055256 and PCT/EP2010/055257 i.e. comprising the steps of:

a) forming a liquid surfactant blend comprising a major amount of surfactant and a minor amount of water, the surfactant part consisting of at least 51 wt% linear alkylbenzene sulfonate and at least one co-surfactant, the surfactant blend consisting of at most 20 wt% nonionic surfactant;
b) drying the liquid surfactant blend of step (a) in an evaporator or drier to a moisture content of less than 1.5 wt% and cooling the output from the evaporator or dryer;
c) feeding the cooled material, which output comprises at least 93 wt% surfactant blend with a major part of LAS, to an extruder, optionally along with less than 10 wt% of other materials such as perfume, fluorescer, and extruding the surfactant blend to form an extrudate while periodically cutting the extrudate to form hard detergent particles with a diameter across the extruder of greater than 2 mm and a thickness along the axis of the extruder of greater than 0.2 mm, provided that the diameter is greater than the thickness;
d) optionally, coating the extruded hard detergent particles with up to 30 wt% coating material, preferably selected from inorganic material and mixtures of such material and nonionic material with a melting point in the range 40 to 90°C.

To facilitate extrusion it may be advantageous for the cooled dried output from the evaporator or drier stage (b) comprising at least 95 wt% preferably 96 wt%, more preferably 97 wt%, most preferably 98 wt% surfactant to be transferred to a mill and milled to particles of less than 1.5 mm, preferably less than 1 mm average diameter before it is fed to the extrusion step (c).
To modify the properties of the milled material a powdered flow aid, such as Aerosil®, Alusil®, or Microsil®, with a particle diameter of from 0.1 to 10 µm may be added to the mill in an amount of 0.5 to 5 wt%, preferably 0.5 to 3 wt% (based on output from the mill) and blended into the particles during milling.
The output from step b, or the intermediate milling step, if used, is fed to the extruder, optionally along with minor amounts (less than 10 wt% total) of other materials such as perfume and /or fluorescer, and the mixture of materials fed to the extruder is extruded to form an extrudate with a diameter of greater than 2 mm, preferably greater than 3 mm, most preferably greater than 4 mm and preferably with a diameter of less than 7 mm, most preferably less than 5 mm, while periodically cutting the extrudate to form hard detergent particles with a maximum thickness of greater than 0.2 mm and less than 3 mm, preferably less than 2 mm, most preferably less than about 1.5 mm and more than about 0.5 mm, even 0.7 mm. Whilst the preferred extrudate is of circular cross section, the invention also encompasses other cross sections such as triangular, rectangular and even complex cross sections, such as one mimicking a flower with rotationally symmetrical "petals". Indeed the invention can be operated on any extrudate that can be forced through a hole in the extruder or extruder plate; the key being that the average thickness of the extrudate should be kept below the level where dissolution will be slow. As discussed above this is a thickness of about 2 mm. Desirably multiple extrusions are made simultaneously and they may all have the same cross section or may have different cross sections. Normally they will all have the same length as they are cut off by the knife. The cutting knife should be as thin as possible to allow high speed extrusion and minimal distortion of the extrudate during cutting. The extrusion should preferably take place at a temperature of less than 45°C, more preferably less than 40°C to avoid stickiness and facilitate cutting. The extrudates according to the present process are cut so that their major dimension is across the extruder and the minor dimension is along the axis of the extruder. This is the opposite to the normal extrusion of surfactants. Cutting in this way increases the surface area that is a "cut" surface. It also allows the extruded particle to expand considerably along its axis after cutting, whilst maintaining a relatively high surface to volume ratio, which is believed to increase its solubility and also results in an attractive biconvex, or lentil, appearance. Elsewhere we refer to this shape as an oblate spheroid. This is essentially a rotation of an ellipse about its minor axis.
It is surprising that at very low water contents the LAS containing surfactant blends can be extruded to make solid detergent particles that are hard enough to be used without any need to be structured by inorganic materials or other structurants as commonly found in prior art extruded detergent particles. Thus, the amount of surfactant in the detergent particle can be much higher and the amount of builder in the detergent particle can be much lower.
Preferably the blend in step (a) comprises at least about 60 wt%, most preferably at least about 70 wt% surfactant and preferably at most about 40 wt%, most preferably at most 30 wt% water, the surfactant part consisting of at least 51 wt% linear alkyl benzene sulphonate salt (LAS) and at least one co-surfactant;
Preferably, the co-surfactant is chosen from the group consisting of: SLES, and nonionic, together with optional soap and mixtures thereof. The only proviso is that when nonionic is used the upper limit for the amount of nonionic surfactant has been found to be 20 wt% of the total surfactant to avoid the dried material being too soft and cohesive to extrude because it has a hardness value less than 0.5 MPa.
Preferably, the surfactant blend is dried in step (b) to a moisture content of less than 1.2 wt%, more preferably less than 1.1 wt%, and most preferably less than 1 wt%.
Drying may suitably be carried out using a wiped film evaporator or a Chemithon Turbo Tube® drier.
The extruded hard detergent particles may be coated by transferring them to a fluid bed and spraying onto them up to 40 wt% (based on coated detergent particle) of inorganic material in aqueous solution and drying off the water.
If the coating material is not contributing to the wash performance of the composition then it is desirable to keep the level of coating as low as possible, preferably less than 35 wt% even less than 30 wt%, especially for larger extruded particles with a surface area to volume ratio of greater than 4 mm^-1.
Surprisingly we have found that the appearance of the coated particles in a package is very pleasing. Without wishing to be bound by theory, we believe that this high quality coating appearance is due to the smoothness of the underlying extruded and cut particle. By starting with a smooth surface, we unexpectedly found it easy to obtain a high quality coating finish (as measured by light reflectance and smoothness) using simple coating techniques.
The detergent composition preferably comprises at least 85 wt% of coated particles. However, compositions with up to 100 wt% of the particles are possible when basic additives are incorporated into the extruded particles, or into their coating. The composition may also comprise, for example, an antifoam granule.
Particles of different colours may be used in admixture, or they can be blended with contrasting powder. Of course, particles of the same colour as one another may also be used to form a full composition. As described above the coating quality and appearance is very good due to the excellent surface of the cut extrudates onto which the coating is applied in association with the large particle size and S/V ratios of the preferred particles.
It is particularly preferred that the detergent particles comprise perfume. The perfume may be added into the extruder or premixed with the surfactant blend in the mill, or in a mixer placed after the mill, either as a liquid or as encapsulated perfume particles. In an alternative process, the perfume may be mixed with a nonionic material and blended. Such a blend may alternatively be applied by coating the extruded particles, for example by spraying it mixed with molten nonionic surfactant. Perfume may also be introduced into the composition by means of a separate perfume granule and then the detergent particle does not need to comprise any perfume.

The Surfactant Blend

Surfactant blends that do not require builders to be present for effective detergency in hard water are preferred. Such blends are called calcium tolerant surfactant blends if they pass the test set out hereinafter. Thus, it may be advantageous if the extruded core is made using a calcium tolerant surfactant blend according to the test herein described. However, the invention may also be of use for washing with soft water, either naturally occurring or made using a water softener. In this case, calcium tolerance is no longer important and blends other than calcium tolerant ones may be used.
LAS can be at least partially replaced by MES, or, less preferably, partially replaced by up to 20 wt % PAS.

Blending

The surfactants are mixed together before being input to the drier. Conventional mixing equipment is used.

Drying

To achieve the very low moisture content of the surfactant blend, scraped film devices may be used. A preferred form of scraped film device is a wiped film evaporator. One such suitable wiped film evaporator is the "Dryex system" based on a wiped film evaporator available from Ballestra S.p.A.. Alternative drying equipment includes tube-type driers, such as a Chemithon Turbo Tube® drier, and soap driers.

Chilling and Milling

The hot material exiting the scraped film drier is subsequently cooled and broken up into suitable sized pieces to feed to the extruder. Simultaneous cooling and breaking into flakes may conveniently be carried out using a chill roll. If the flakes from the chill roll are not suitable for direct feed to the extruder then they can be milled in a milling apparatus and /or they can be blended with other liquid or solid ingredients in a blending and milling apparatus, such as a ribbon mill. Such milled or blended material is desirably of particle size 1 mm or less for feeding to the extruder.
It is particularly advantageous to add a milling aid at this point in the process. Particulate material with a mean particle size of 10 nm to 10 µm is preferred for use as a milling aid. Among such materials, there may be mentioned, by way of example: aerosil®, alusil®, and microsil®.

Extruding and Cutting

The extruder provides further opportunities to blend in ingredients other than surfactants, or even to add further surfactants. However, it is generally preferred that all of the anionic surfactant, or other surfactant supplied in admixture with water; i.e. as paste or as solution, is added into the drier to ensure that the water content can then be reduced and the material fed to and through the extruder is sufficiently dry. Additional materials that can be blended into the extruder are thus mainly those that are used at very low levels in a detergent composition: such as fluorescer, shading dye, enzymes, perfume, silicone antifoams, polymeric additives and preservatives. The limit on such additional materials blended in the extruder has been found to be about 10 wt%, but it is preferred for product quality to be ideal to keep it to a maximum of 5 wt%. Solid additives are generally preferred. Liquids, such as perfume may be added at levels up to 2.5 wt%, preferably up to 1.5 wt%. Solid particulate structuring (liquid absorbing) materials or builders, such as zeolite, carbonate, silicate are preferably not added to the blend being extruded. These materials are not needed due to the self structuring properties of the very dry LAS-based feed material. If any is used the total amount should be less than 5 wt%, preferably less than 4 wt%, most preferably less than 3 wt%. At such levels no significant structuring occurs and the inorganic particulate material is added for a different purpose, for instance as a flow aid to improve the feed of particles to the extruder.
The output from the extruder is shaped by the die plate used. The extruded material has a tendency to swell up in the centre relative to the periphery. We have found that if a cylindrical extrudate is regularly sliced as it exits the extruder the resulting shapes are short cylinders with two convex ends. These particles are herein described as oblate spheroids, or lentils. This shape is pleasing visually.

Coating

An advantageous variant of the process takes the sliced extruded particles and coats them. This allows the particles to be coloured easily. It also further reduces the stickiness of the hygroscopic surfactant core to a point where the particles are free flowing. Coating makes them more suitable for use in detergent compositions that may be exposed to high humidity for long periods.
By coating such large extruded particles the thickness of coating obtainable by use of a coating level of say 5 wt% is much greater than would be achieved on typically sized detergent granules (0.5-2mm diameter sphere).
The extruded particles can be considered as oblate spheroids with a major radius "a" and minor radius "b". Hence, the surface area(S) to volume (V) ratio can be calculated as: $\frac{S}{V} = \frac{3}{2 b} + \frac{3 b}{4 \in a^{2}} \ln {(\frac{1 + \in}{1 - \in})}_{mm - 1}$
When ∈ is the eccentricity of the particle.
For optimum dissolution properties, this surface area to volume ratio must be greater than 3 mm-1. However, the coating thickness is inversely proportional to this coefficient and hence for the coating the ratio "Surface area of coated particle" divided by "Volume of coated particle" should be less than 15 mm-1.
Although the skilled person might assume that any known coating may be used, for instance organic, including polymer, it has been found to be particularly advantageous to use an inorganic coating deposited by crystallisation from an aqueous solution as this appears to give positive dissolution benefits and the coating gives a good colour to the detergent particle, even at lower coating levels. An aqueous spray-on of coating solution in a fluidised bed may also generate a further slight rounding of the detergent particles during the fluidisation process.
Suitable inorganic coating solutions include sodium carbonate, possibly in admixture with sodium sulphate, and sodium chloride. Food dyes, shading dyes, fluorescer and other optical modifiers can be added to the coating by dissolving them in the spray-on solution or dispersion. Use of a builder salt such as sodium carbonate is particularly advantageous because it allows the detergent particle to have an even better performance by buffering the system in use at an ideal pH for maximum detergency of the anionic surfactant system. It also increases ionic strength, which is known to improve cleaning in hard water, and it is compatible with other detergent ingredients that may be admixed with the coated extruded detergent particles. If a fluid bed is used to apply the coating solution, the skilled worker will know how to adjust the spray conditions in terms of Stokes number and possibly Akkermans number (FNm) so that the particles are coated and not significantly agglomerated. Suitable teaching to assist in this may be found in EP1187903 , EP993505 and Powder technology 65 (1991) 257-272 (Ennis).
It will be appreciated by those skilled in the art that multiple layered coatings, of the same or different coating materials, could be applied, but a single coating layer is preferred, for simplicity of operation, and to maximise the thickness of the coating. The amount of coating should lie in the range 3 to 50 wt% of the particle, preferably 20 to 40 wt% for the best results in terms of anti-caking properties of the detergent particles.

The Extruded Particulate Detergent Composition

The coated particles dissolve easily in water and leave very low or no residues on dissolution, due to the absence of insoluble structurant materials such as zeolite. The coated particles have an exceptional visual appearance, due to the smoothness of the coating coupled with the smoothness of the underlying particles, which is also believed to be a result of the lack of particulate structuring material in the extruded particles.

SHAPE

The coated detergent particle is curved. The coated detergent particle is preferably lenticular (shaped like a whole dried lentil), an oblate ellipsoid, where z and y are the equatorial diameters and x is the polar diameter; preferably y = z.
The size is such that y and z are at least 3 mm, preferably 4 mm, most preferably 5 mm and x lies in the range 1 to 2 mm.
The coated laundry detergent particle may be shaped as a disc.

CORE COMPOSITION

The core is primarily surfactant. It may also include detergency additives, such as perfume, shading dye, enzymes, cleaning polymers and soil release polymers.

SURFACTANT

The coated laundry detergent particle comprises between 50 to 90 wt% of a surfactant, most preferably 70 to 90 wt%. In general, the nonionic and anionic surfactants of the surfactant system may be chosen from the surfactants described "Surface Active Agents" Vol. 1, by Schwartz & Perry, Interscience 1949, Vol. 2 by Schwartz, Perry & Berch, Interscience 1958, in the current edition of "McCutcheon's Emulsifiers and Detergents" published by Manufacturing Confectioners Company or in "Tenside Taschenbuch", H. Stache, 2nd Edn., Carl Hauser Verlag, 1981. Preferably the surfactants used are saturated.

1) Anionic Surfactants

Suitable anionic detergent compounds that may be used are usually water-soluble alkali metal salts of organic sulphates and sulphonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term alkyl being used to include the alkyl portion of higher acyl radicals. Examples of suitable synthetic anionic detergent compounds are sodium and potassium alkyl sulphates, especially those obtained by sulphating higher C8 to C18 alcohols, produced for example from tallow or coconut oil, sodium and potassium alkyl C9 to C20 benzene sulphonates, particularly sodium linear secondary alkyl C10 to C15 benzene sulphonates; and sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum. Most preferred anionic surfactants are sodium lauryl ether sulphate (SLES), particularly preferred with 1 to 3 ethoxy groups, sodium C10 to C15 alkyl benzene sulphonates and sodium C12 to C18 alkyl sulphates. Also applicable are surfactants such as those described in EP-A-328 177 (Unilever), which show resistance to salting out, the alkyl polyglycoside surfactants described in EP-A-070 074 , and alkyl monoglycosides. The chains of the surfactants may be branched or linear.
Soaps may also be present. The fatty acid soap used preferably contains from about 16 to about 22 carbon atoms, preferably in a straight chain configuration. The anionic contribution from soap may be from 0 to 30 wt% of the total anionic. Use of more than 10 wt% soap is not preferred.
Preferably, at least 50 wt% of the anionic surfactant is selected from: sodium C11 to C15 alkyl benzene sulphonates; and, sodium C12 to C18 alkyl sulphates.
Preferably, the anionic surfactant is present in the coated laundry detergent particle at levels between 15 to 85 wt%, more preferably 50 to 80wt%.

2) Non-Ionic Surfactants

Suitable non-ionic detergent compounds which may be used include, in particular, the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example, aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide. Preferred nonionic detergent compounds are C6 to C22 alkyl phenol-ethylene oxide condensates, generally 5 to 25 EO, i.e. 5 to 25 units of ethylene oxide per molecule, and the condensation products of aliphatic C8 to C18 primary or secondary linear or branched alcohols with ethylene oxide, generally 5 to 50 EO. Preferably, the non-ionic is 10 to 50 EO, more preferably 20 to 35 EO. Alkyl ethoxylates are particularly preferred.
Preferably the non-ionic surfactant is present in the coated laundry detergent particle at levels between 5 to 75 wt%, more preferably 10 to 40 wt%.
Cationic surfactant may be present as minor ingredients at levels preferably between 0 to 5 wt%.
Preferably all the surfactants are mixed together before being dried. Conventional mixing equipment may be used. The surfactant core of the laundry detergent particle may be formed by roller compaction and subsequently coated with an inorganic salt.

Calcium Tolerant Surfactant System

In another aspect the core is calcium tolerant and this is a preferred aspect because this reduces the need for a builder.
Surfactant blends that do not require builders to be present for effective detergency in hard water are preferred. Such blends are called calcium tolerant surfactant blends if they pass the test set out hereinafter. However, the invention may also be of use for washing with soft water, either naturally occurring or made using a water softener. In this case, calcium tolerance is no longer important and blends other than calcium tolerant ones may be used.
Calcium-tolerance of the surfactant blend is tested as follows:
The surfactant blend in question is prepared at a concentration of 0.7 g surfactant solids per litre of water containing sufficient calcium ions to give a French hardness of 40 (4 x 10-3 Molar Ca2+). Other hardness ion free electrolytes such as sodium chloride, sodium sulphate, and sodium hydroxide are added to the solution to adjust the ionic strength to 0.05M and the pH to 10. The adsorption of light of wavelength 540 nm through 4 mm of sample is measured 15 minutes after sample preparation. Ten measurements are made and an average value is calculated. Samples that give an absorption value of less than 0.08 are deemed to be calcium tolerant.
Examples of surfactant blends that satisfy the above test for calcium tolerance include those having a major part of LAS surfactant (which is not of itself calcium tolerant) blended with one or more other surfactants (co-surfactants) that are calcium tolerant to give a blend that is sufficiently calcium tolerant to be usable with little or no builder and to pass the given test. Suitable calcium tolerant co-surfactants include SLES 1-7EO, and alkyl ethoxylate non-ionic surfactants, particularly those with melting points less than 40°C.
A LAS/SLES surfactant blend has a superior foam profile to a LAS Nonionic surfactant blend and is therefore preferred for hand washing formulations requiring high levels of foam. SLES may be used at levels of up to 30%.
A LAS/NI surfactant blend provides a harder particle and its lower foam profile makes it more suited for automatic washing machine use.

THE COATING

The main component of the coating is the water soluble inorganic salt. Other water compatible ingredients may be included in the coating. For example fluorescer, SCMC, additional dyes e.g. shading dyes, pigments, silicate.

Water Soluble Inorganic Salts

The water soluble inorganic salts are preferably selected from sodium carbonate, sodium chloride, sodium silicate and sodium sulphate, or mixtures thereof, most preferably 70 to 100 wt % sodium carbonate. The water soluble inorganic salt is present as a coating on the particle. The water soluble inorganic salt is preferably present at a level that reduces the stickiness of the laundry detergent particle to a point where the particles are free flowing.
It will be appreciated by those skilled in the art that multiple layered coatings, of the same or different coating materials, could be applied, but a single coating layer is preferred, for simplicity of operation, and to maximise the thickness of the coating. The amount of coating should lay in the range 1 to 40 wt% of the particle, preferably 20 to 40 wt%, even more preferably 25 to 35 wt% for the best results in terms of anti-caking properties of the detergent particles.
The coating is applied to the surface of the surfactant core, by crystallisation from an aqueous solution of the water soluble inorganic salt. The aqueous solution preferably contains greater than 50g/L, more preferably 200 g/L of the salt. An aqueous spray-on of the coating solution in a fluidised bed has been found to give good results and may also generate a slight rounding of the detergent particles during the fluidisation process. Drying and/or cooling may be needed to finish the process.
By coating the large detergent particles of the current invention the thickness of coating obtainable by use of a coating level of say 5 wt% is much greater than would be achieved on typically sized detergent granules (0.5-2 mm diameter sphere).
For optimum dissolution properties, this surface area to volume ratio must be greater than 3 mm^-1. However, the coating thickness is inversely proportional to this coefficient and hence for the coating the ratio "Surface area of coated particle" divided by "Volume of coated particle" should be less than 15 mm^-1.
A preferred calcium tolerant coated laundry detergent particle comprises 15 to 100 wt% anionic surfactant of which 20 to 30 wt% is sodium lauryl ether sulphate.

The Coated Detergent Particle

Preferably, the coated detergent particle comprises from 70 to 100 wt%, more preferably 85 to 90 wt%, of a detergent composition in a package.
Preferably, the coated detergent particles are substantially the same shape and size by this is meant that at least 90 to 100% of the coated laundry detergent particles in the in the x, y and z dimensions are within a 20%, preferably 10%, variable from the largest to the smallest coated laundry detergent particle in the corresponding dimension.

Water Content

The particle preferably comprises from 0 to 15 wt% water, more preferably 0 to 10 wt%, most preferably from 1 to 5 wt% water, at 293K and 50% relative humidity. This facilitates the storage stability of the particle and its mechanical properties.

Other Ingredients

The ingredients described below may be present in the coating or the core.

Fluorescent Agent

The coated laundry detergent particle preferably comprises a fluorescent agent (optical brightener). Fluorescent agents are well known and many such fluorescent agents are available commercially. Usually, these fluorescent agents are supplied and used in the form of their alkali metal salts, for example, the sodium salts. The total amount of the fluorescent agent or agents used in the composition is generally from 0.005 to 2 wt%, more preferably 0.01 to 0.1 wt%. Suitable Fluorescers for use in the invention are described in chapter 7 of Industrial Dyes edited by K. Hunger 2003 Wiley-VCH ISBN 3-527-30426-6.
Preferred fluorescers are selected from the classes distyrylbiphenyls, triazinylaminostilbenes, bis(1,2,3-triazol-2-yl)stilbenes, bis(benzo[b]furan-2-yl)biphenyls, 1,3-diphenyl-2-pyrazolines and courmarins. The fluorescer is preferably sulphonated.
Preferred classes of fluorescer are: Di-styryl biphenyl compounds, e.g. Tinopal (Trade Mark) CBS-X, Di-amine stilbene di-sulphonic acid compounds, e.g. Tinopal DMS pure Xtra and Blankophor (Trade Mark) HRH, and Pyrazoline compounds, e.g. Blankophor SN. Preferred fluorescers are: sodium 2 (4-styryl-3-sulfophenyl)-2H-napthol[1,2-d]triazole, disodium 4,4'-bis{[(4-anilino-6-(N methyl-N-2 hydroxyethyl) amino 1,3,5-triazin-2-yl)]amino}stilbene-2-2' disulfonate, disodium 4,4'-bis{[(4-anilino-6-morpholino-1,3,5-triazin-2-yl)]amino} stilbene-2-2' disulfonate, and disodium 4,4'-bis(2-sulfostyryl)biphenyl.
Tinopal® DMS is the disodium salt of disodium 4,4'-bis{[(4-anilino-6-morpholino-1,3,5-triazin-2-yl)]amino} stilbene-2-2' disulfonate. Tinopal® CBS is the disodium salt of disodium 4,4'-bis(2-sulfostyryl)biphenyl.

Perfume

Preferably, the composition comprises a perfume. The perfume is preferably in the range from 0.001 to 3 wt%, most preferably 0.1 to 1 wt%. Many suitable examples of perfumes are provided in the CTFA (Cosmetic, Toiletry and Fragrance Association) 1992 International Buyers Guide, published by CFTA Publications and OPD 1993 Chemicals Buyers Directory 80th Annual Edition, published by Schnell Publishing Co.
It is commonplace for a plurality of perfume components to be present in a formulation. In the compositions of the present invention it is envisaged that there will be four or more, preferably five or more, more preferably six or more or even seven or more different perfume components.
In perfume mixtures preferably 15 to 25 wt% are top notes. Top notes are defined by Poucher (Journal of the Society of Cosmetic Chemists 6(2):80 [1955]). Preferred top-notes are selected from citrus oils, linalool, linalyl acetate, lavender, dihydromyrcenol, rose oxide and cis-3-hexanol.
It is preferred that the coated laundry detergent particles do not contain a peroxygen bleach, e.g., sodium percarbonate, sodium perborate, and peracid.

Polymers

The composition may comprise one or more further polymers. Examples are carboxymethylcellulose, poly (ethylene glycol), poly(vinyl alcohol), polyethylene imines, ethoxylated polyethylene imines, water soluble polyester polymers polycarboxylates such as polyacrylates, maleic/acrylic acid copolymers and lauryl methacrylate/acrylic acid copolymers.

Enzymes

One or more enzymes are preferably present in the composition.
Preferably the level of each enzyme is from 0.0001 wt% to 0.5 wt% protein.
Especially contemplated enzymes include proteases, alpha-amylases, cellulases, lipases, peroxidases/oxidases, pectate lyases, and mannanases, or mixtures thereof.
Suitable lipases include those of bacterial or fungal origin. Chemically modified or protein engineered mutants are included. Examples of useful lipases include lipases from Humicola (synonym Thermomyces), e.g. from H. lanuginosa (T. lanuginosus) as described in EP 258 068 and EP 305 216 or from H. insolens as described in WO 96/13580 , a Pseudomonas lipase, e.g. from P. alcaligenes or P. pseudoalcaligenes ( EP 218 272 ), P. cepacia ( EP 331 376 ), P. stutzeri ( GB 1,372,034 ), P. fluorescens, Pseudomonas sp. strain SD 705 ( WO 95/06720 and WO 96/27002 ), P. wisconsinensis ( WO 96/12012 ), a Bacillus lipase, e.g. from B. subtilis (Dartois et al. (1993), Biochemica et Biophysica Acta, 1131, 253-360), B. stearothermophilus ( JP 64/744992 ) or B. pumilus ( WO 91/16422 ).
Other examples are lipase variants such as those described in WO 92/05249 , WO 94/01541 , EP 407 225 , EP 260 105 , WO 95/35381 , WO 96/00292 , WO 95/30744 , WO 94/25578 , WO 95/14783 , WO 95/22615 , WO 97/04079 and WO 97/07202 , WO 00/60063 , WO 09/107091 and WO09/111258 .
Preferred lipase enzymes include Lipolase™ and Lipolase Ultra™, Lipex™ (Novozymes A/S) and Lipoclean™.
The method of the invention may be carried out in the presence of phospholipase classified as EC 3.1.1.4 and/or EC 3.1.1.32. As used herein, the term phospholipase is an enzyme that has activity towards phospholipids.
Phospholipids, such as lecithin or phosphatidylcholine, consist of glycerol esterified with two fatty acids in an outer (sn-1) and the middle (sn-2) positions and esterified with phosphoric acid in the third position; the phosphoric acid, in turn, may be esterified to an amino-alcohol. Phospholipases are enzymes that participate in the hydrolysis of phospholipids. Several types of phospholipase activity can be distinguished, including phospholipases A1 and A2 which hydrolyze one fatty acyl group (in the sn-1 and sn-2 position, respectively) to form lysophospholipid; and lysophospholipase (or phospholipase B) which can hydrolyze the remaining fatty acyl group in lysophospholipid. Phospholipase C and phospholipase D (phosphodiesterases) release diacyl glycerol or phosphatidic acid respectively.
Suitable proteases include those of animal, vegetable or microbial origin. Microbial origin is preferred. Chemically modified or protein engineered mutants are included. The protease may be a serine protease or a metallo protease, preferably an alkaline microbial protease or a trypsin-like protease. Suitable protease enzymes include Alcalase™, Savinase™, Primase™, Duralase™, Dyrazym™, Esperase™, Everlase™, Polarzyme™, and Kannase™, (Novozymes A/S), Maxatase™, Maxacal™, Maxapem™, Properase™, Purafect™, Purafect OxP™, FN2™, and FN3™ (Genencor International Inc.).
The method of the invention may be carried out in the presence of cutinase. classified in EC 3.1.1.74. The cutinase used according to the invention may be of any origin. Preferably, cutinases are of microbial origin, in particular of bacterial, of fungal or of yeast origin.
Suitable amylases (alpha and/or beta) include those of bacterial or fungal origin. Chemically modified or protein engineered mutants are included. Amylases include, for example, alpha-amylases obtained from Bacillus, e.g. a special strain of B. licheniformis, described in more detail in GB 1,296,839 , or the Bacillus sp. strains disclosed in WO 95/026397 or WO 00/060060 . Suitable amylases are Duramyl™, Termamyl™, Termamyl Ultra™, Natalase™, Stainzyme™, Fungamyl™ and BAN™ (Novozymes A/S), Rapidase™ and Purastar™ (from Genencor International Inc.).
Suitable cellulases include those of bacterial or fungal origin. Chemically modified or protein engineered mutants are included. Suitable cellulases include cellulases from the genera Bacillus, Pseudomonas, Humicola, Fusarium, Thielavia, Acremonium, e.g. the fungal cellulases produced from Humicola insolens, Thielavia terrestris, Myceliophthora thermophila, and Fusarium oxysporum disclosed in US 4,435,307 , US 5,648,263 , US 5,691,178 , US 5,776,757 , WO 89/09259 , WO 96/029397 , and WO 98/012307 . Cellulases include Celluzyme™, Carezyme™, Endolase™, Renozyme™ (Novozymes A/S), Clazinase™ and Puradax HA™ (Genencor International Inc.), and KAC-500(B)™ (Kao Corporation).
Suitable peroxidases/oxidases include those of plant, bacterial or fungal origin. Chemically modified or protein engineered mutants are included. Examples of useful peroxidases include peroxidases from Coprinus, e.g. from C. cinereus, and variants thereof as those described in WO 93/24618 , WO 95/10602 , and WO 98/15257 . Peroxidases include Guardzyme™ and Novozym™ 51004 (Novozymes A/S).
Further suitable enzymes are disclosed in WO2009/087524 , WO2009/090576 , WO2009/148983 and WO2008/007318 .

Enzyme Stabilizers

Any enzyme present in the composition may be stabilized using conventional stabilizing agents, e.g., a polyol such as propylene glycol or glycerol, a sugar or sugar alcohol, lactic acid, boric acid, or a boric acid derivative, e.g., an aromatic borate ester, or a phenyl boronic acid derivative such as 4-formylphenyl boronic acid, and the composition may be formulated as described in e.g. WO 92/19709 and WO 92/19708 .
Sequestrants may be present in the detergent particles.
The invention will be further described with reference to the following non-limiting examples.

EXAMPLES

Example 1: (particle manufacture)

A coated detergent particle colour were created containing Acid Violet 50 in the core.
The particles were oblate elipisoids which had the following dimensions x= 1.1 mm y= 4.0 mm z= 5.0 mm. The particles weighed ∼0.013g each. The Particle appeared a gorgeous violet to the eye

Preparation of Core

1962.5g of dried, milled surfactant blend (LAS/NI 85/15 by weight) was thoroughly mixed with 37.38g of perfume oil and 0.124g of Acid Violet 50 dye. The mixture was then extruded using a ThermoFisher 24HC twin screw extruder, operated at a rate of 8kg/hr. Inlet temperature of the extruder was set at 20°C, rising to 40°C just prior to the die-plate. The die-plate used was drilled with 6 circular orifices of 5mm diameter.
The extruded product was cut after the die-plate using a high speed cutter set up to produce particle with a thickness of ∼1.1 mm.

Coating of Particle

764g of the extrudates above were charged to the fluidising chamber of a Strea 1 laboratory fluid bed drier (Aeromatic-Fielder AG) and spray coated using 1069g of a solution containing 320.7g of sodium carbonate in 748.3g of water, using a top-spray configuration.
The coating solution was fed to the spray nozzle of the Strea 1 via a peristaltic pump (Watson-Marlow model 101U/R) at an initial rate of 3.3g/min, rising to 9.1g/min during the course of the coating trial.
The Fluid bed coater was operated with an initial air inlet air temperature of 55°C increasing to 90°C during the course of the coating trial whilst maintaining the outlet temperature in the range 45-50°C throughout the coating process.

Example 2: (Coated detergent particle colour)

The colour of the particles of example 1 was measured using a reflectometer (UV-excluded) and expressed as the CIE L*a*b* value. The results are shown below

	L*	a*	b*
Particle : Dye in the Core	76.2	2.9	-7.9

L* is the lightness, as objects become coloured L* drops
a* is the red-green axis with +ve values indicating a red colour and -ve a green colour
b* is the yellow-blue axis with +ve values indicating a yellow colour and -ve a blue colour

The particle is clearly violet with a negative b* value.

Example 3: (Liquor colour)

2.25g of the Particle of example were dissolved in 100ml of deminerailised water. The solutions were centrifuged at 15 minutes for 11000 RPM and the colour of the liquid measured on A UV-VIS absorption spectrometer. The liquid appeared violet to the eye.
The UV-VIS spectrum gave the spectrum of Acid Violet 50 for both solutions with a maximum absorption at 570nm. The optical densities are given in the table below

Optical density (5cm) at 570nm

Particle : Dye in Core 0.175

Both particles effectively deliver Acid Violet 50 to solution.

Claims

A packaged particulate detergent composition contained in a package, the package comprising at least one transparent portion and the composition comprising greater than 50 wt% detergent surfactant and at least 70 % by number of the particles comprising
(i) a core, comprising mainly surfactant and from 0.0001 to 0.1% dye preferably 0.001 to 0.01% dye, wherein the dye is selected from anionic dyes and non-ionic dyes; and

(ii) a coating, comprising water soluble inorganic salt deposited by crystallisation from an aqueous solution, the particles being substantially the same shape and size as one another, characterised in that each particle has perpendicular dimensions x, y and z, wherein x is from 0.2 to 2 mm, y is from 2.5 to 8mm (preferably 3 to 8 mm), and z is from 2.5 to 8 mm (preferably 3 to 8 mm).
A packaged composition according to any preceding claim wherein the at least one transparent portion has a transmittance of more than 25%, more preferably more than 30%, more preferably more than 40%, more preferably more than 50% in the visible part of the spectrum.
A packaged composition according to any preceding claim wherein the at least one transparent portion comprises an aperture in an opaque portion.
A packaged composition according to any preceding claim wherein the at least one transparent portion comprises the whole package, which may include one or more opaque labels.
A packaged composition according to any preceding claim wherein the dye is selected from those having: anthraquinone; mono-azo; bis-azo; xanthene; phthalocyanine; and, phenazine chromophores.
A packaged composition according to any preceding claim wherein the dye is selected from those having: anthraquinone and mono-azo chromophores.
A packaged composition according to any preceding claim in which the number percentage of the packaged composition of particles comprising the core and coating is at least 85%.
A packaged composition according to any preceding claim wherein the dye is selected from acid dyes; disperse dyes and alkoxylated dyes.
A packaged composition according to any preceding claim in which the coating comprises sodium carbonate.
A packaged composition according to any preceding claim in which the coated particles are oblate spheroids with diameter of 3 to 6 mm and thickness of 1 to 2 mm.
A packaged composition according to any preceding claim in which a major portion by number of the particles in the composition are coloured other than white.
A packaged composition according to any preceding claim in which the package is resealable.
A packaged composition according to claim 12 in which the package is resealed by means of a screw cap, which also serves as a dosing measure.
A packaged composition according to any preceding claim, which is a laundry detergent composition.