GB2360526A - Selective detergent colouration - Google Patents

Abstract

A method of coating detergent products containing surfactants using ink jet printing is disclosed. Dyes, pigments and inks of preferred composition are provided which show a tendency to bleed and retain good stability.

Description

SELECTIVE DETERGENT COLOURATION FIELD OF THE INVENTION The present invention relates to a method of selectively surface coating, particularly colouring, detergent compositions.

<B><U>BACKGROUND</U></B><U> TO THE INVENTION</U> Detergent compositions are primarily composed of colourless components with various actions. Hence, particularly with consumer products, it has often been the practice to colour the product or parts of the product so as to give a visual indication of a chemical, performance or other in-use attribute. This is achieved by adding a dye to the composition or part of the composition, for example, as individual granules of a powder to give speckles. With tablet form products areas of the tablet are made separately from compositions of different colours.

This approach is due to the nature of detergent systems which are designed to solubilise organic materials and particulate materials (ie dirt and soils) to which dyes are closely related. Colourant systems therefore have a tendency to be distributed<B>by</B> the surfactant components of a composition and hence 'smudge', diffuse or otherwise discolour towards homogeneous colouration. Hence, for example, separate colouration with speckles typically places the colourant on particles not containing surfactant, examples being bleach activator (ex Hoechst) and enzymes (ex Novo) granules where the colour is itself incorporated homogeneously. Detergents tablets and toilet block compositions with layers of differing colours are known but colour diffusion is common, hence only gross blocks of homogeneously coloured material are used (cf UK trademark applications 2,149,344, 2,165,230 (Benckiser) by example).

Examples of dye use in detergents include: WO 9720914 (CDCC Co.) discloses a cleaning composition containing particles of dye, WO 9907817 and WO 9719163 (Procter & Gamble) disclose particles with dye in a cleaning composition which decolourise after dissolution. WO<B>9620995</B> (Texas inc) discloses a dye in a decontamination powder and EP<B>0352892</B> (Kao) discloses a granular, concentrated detergent composition containing a fluorescent dye. The use of dyes as optional components is also disclosed in much of the art on powdered detergents. These uses disclose homogeneous incorporation of the dye in whatever part of the composition it may be associated with.

EP<B>0728804</B> (IFF) discloses up to<B>5%</B> dye in a toilet rim block, EP 0423391 (Kiwi) and WO <B>9847998 (S. C.</B> Johnson) also disclose similar blocks. The use of dyes as optional components is also disclosed in much of the art on detergent blocks and tablets. These uses disclose homogeneous incorporation of the dye in whatever part of the composition it may be associated with.

EP<B>0635569</B> (Unilever) discloses dye particles in a non-aqueous liquid detergent composition, WO<B>9808927</B> (Colgate) discloses a liquid colour/perfume concentrate containing a polymer bound water soluble azo dye and a perfume for use in detergents compositions. The use of dyes as optional components is also disclosed in much of the art on detergents liquids. These uses disclose homogeneous incorporation of the dye in whatever part of the composition it may be associated with.

It is evident from the art that whilst the use of dyes is well established all uses disclose their homogeneous incorporation in detergents compositions. It is maintained that there is a prejudice in the art against the incorporation of dye and colorific components other than<B>by</B> homogeneous incorporation. This has two significant deficiencies. First since only the dye on the surface of a solid or opaque liquid composition is visible only a small fraction of the dye is actually being used in its function. This is both significant economically and also in the intensity of the colours obtainable. Intense colouration requires high dye levels which can give intense colours and leads to the risk of dyeing the article to be cleaned, thus restricting the suitable dyes, as described in WO 9704068 and EP 0754749 (Procter). Whilst a 'disclosing' function in dyeing a substrate can be used as described in EP 0631610 (Unilever), which discloses a cleaning composition with a protein disclosing dye, this is largely undesirable in a consumer product as it highlights any ineffectiveness in the cleaning process. In addition the homogeneous incorporation of a dye requires complex mechanical arrangements in order to derive patterns etc.

Examples of localised dye incorporation have been disclosed in EP<B>0767829,</B> EP<B>0716685</B> and EP<B>0767830</B> (Henkel) disclose extruded enzyme granules for use in washing to which a dye- and/or pigment-containing coating can be applied. These granules are of potential application as one component of a detergent but are not detergents and do not contain surfactant.

Localised dye inclusion in a detergent is disclosed in EP<B>0333270</B> (Procter) which discloses a photo activator dye composition for detergent wherein the dye is held in a localised region of the composition as micro capsules. In this instance the dye is physically separated from the detergent in separate capsules which are themselves homogeneously incorporated and is not conceptually different from a speckle.

Surprisingly it has been found that the incorporation of low levels of colourant incorporated non- homogeneously as a thin layer gives improved colour intensity with particularly low levels of Colourant whilst enabling high definition rendition with good storage stability.

The present invention provides a method of applying a surface coating to a detergent material using<B>by</B> the printing of a pigment ink. In particular using ink<B>j</B> ey printing.

DRIATI-M <U>DESCRIPTION OF THE</U> INVENTI The invention comprises a detergent composition, preferably as a tablet, a colourant, preferably formulated as an ink and a method of applying the ink, preferably using an ink jet printing method.

Detergent products according to the invention comprise a detersive surfactant and optional additional detergent components as desribed below: Detersive surfactant Any surfactant materials capable of reducing the air water surface tension of pure water when incorporated at a level of<B>1%</B> is within the scope of the invention. The detersive surfactant detergent formulation in accordance with the invention will include at least one surface active agent which may, for example, be an anionic, cationic, non-anionic or amphoteric surface active agent. Any of the surface active agents widely used in detergent formulations may be employed in the present invention. Such agents are typically employed in amounts of from I to 25%, preferably from 5 to 20% by weight in a detergent formulation.

<B>If</B> an amphoteric surface active agent is used it may be present in the formulation in an amount of 0. 1 to 10% by weight, more preferably 0.5 to 5%, even more preferably I to 4% on the same basis.

The amphoteric surface active agent may be betaine surface active agent. Preferred betaines may be either of the formula (I) or (II).

In the above formula, R1 and R2may be the same or differentCl-4alkyl groups whereas W is an alkyl group having 8-22 carbon atoms, more preferably 12 to 18 carbon atoms e.g. mixed CIO to C 14' The preferred betaine for use is cocoamidopropyl betaine.

An alternative amphoteric surface active agent for use in the formulation of the invention is a glycinate of the formula R3NHCH2CO2H where R3 is as defined above.

Other suitable materials are as given in chapter 1 of "Amphoteric Surfactants", e.g. Lomax Ed, Marcel Decker, New York<B>1996.</B>

It is<B>highly</B> preferred that a cationic surface active agent is employed in conjunction with the amphoteric surface active agent. The cationic surface active agent is preferably used in an amount of up to 2%<B>by</B> weight of the formulation and is conveniently added in conjunction with the clay. Examples of suitable cationic surface active agents include quaternary ammonium salts having three lower (CI-4) alkyl groups (preferably methyl groups) and a long chain (Cs-20) alkyl group, e.g. coco trimethyl ammonium chloride. Further examples include alkyl pyridiniurn salts and other compounds in which the nitrogen atom of the pyridine assumes a quaternary form, e.g. as in an alkyl pyridinium bromide.

Further examples of cationic surface active agents which may be used include amine and imidazoline salts.

<B>If</B> an anionic surface active agent is used then it is preferably present in the formulation in an amount of up to 20%, more preferably up to 10%, even more preferably up to 5% by weight of the formulation. Examples of anionic surface active agents which may be employed include alkyl aryl sulphonates, alkyl sulphates, ether sulphates and ether carboxylates all as conventionally employed in laundry detergent formulations. Di-anionic surfactants are noted as being particularly useful. Anionics with C 10 to C20, more preferably with, C 12 to C 18 alkyl chains are preferred.

If a non-ionic surface active agent is used then it is preferably present in an amount of up to 20% by weight of the formulation, more preferably 2 to 10% on the same basis. Examples of predominantly liqiuid non-ionic surface active agents which may be used include alkoxylates, ethylene oxide/propylene oxide block copolymers, alkanolamides (e.g. monoethanolamides and diethanolamides), esters and amine oxides. Non-ionics with C 10 to C20, more preferably with, C 12 to C 18 alkyl chains are preferred.

If a liquid non-ionic surface active agent is to be included then it may for example an alcohol ethoxylate. The alcohol residue (which may be of a primary or secondary alcohol) may for example comprise 8 to 18 carbon atoms and be ethoxylated with an average of 3 to 20 moles of ethylene oxide per mole of alcohol.

Suitable liquid non-ionic surface active agents are available from ICI under the designations SYNPERONIC A3 and SYNPERONIC A7. Mixtures of the A7 and A3 active agents may also be used. Also suitable are LUTENSOL A03 and LUTENSOL A07 (ex BASF).

Examples of solid non-ionic surface active agents which may be used in the formulation in accordance with the first aspect of the formulation include alkyl(C8-22)PolyglycoSides. The preferred glycoside employed in the present invention is a glucoside (i.e. based on glucose), functionalised with a primary alcohol (e.g. C12-C14). More preferably the glucoside is in the form of a polyglucoside, with a preferred degree of polymerisation of between 1-2, most preferably about 1.4. Non-ionic surface active agents may be used in the form of particles or granules containing at least<B>30% by</B> weight, more preferably at least 40%<B>by</B> weight of solid non-ionic surface active agent.

<B>A</B> suitable polyglycosides are available under the name Glucopan (Henkel). Preferably used as Glucopon <B>G50</B> granules<B>(50%</B> APG Glucon, <B>50%</B> sulphate).

The surfactant can be present at up to<B>2S%,</B> more preferably between<B>I%</B> and 20%. For textile washing compositions the most preferable range is between<B>10</B> and 20% and for hard surface cleaning between<B>I</B> and<B>5%</B> and for fabric refresher and air freshener products less than<B>1 %.</B> The preferred surfactant is one carrying an electrical charge, most preferably an amphoteric: or anionic surfactant.

Cyclodextrins and cyclodextrinoids, optionally as alcohol, amide, ether, ester, hydrophobised, conjugated, granulated, encapsulated and solubilised, denivitised and embodied as such are all envisaged as being potentially incorporated ways of changing their use provided that they retain some ability to complex smaller molecules.

Cyclodextnin incorporation of between 0 and 5%, more preferably between 0.05 and 2%, most preferably between 0.075 and 1.25% is within the scope of the invention.

Additional detergent components Builder The formulation may include at least one builder salt in a total amount of 0. 1 % to 5 0% by weight of the formulation. Mixtures of builder salts are typically employed. The builder may be for example be an alkali metal phosphate or alkali metal carbonate. The person skilled in the art will select a suitable combination of phosphates from ortho, pyro and triphosphates. In particular alkali metal tniphosphates with a Phase 1 content of greater than 40% are preferable for applications requiring rapid dissolution, whereas for applications requiring slow release a Phase 2 content of greater than 40% is desirable. Similarly the degree of hydration of the salts will be chosen, salts with less than 5% water of hydration are preferred. Other suitable builders are zeolites, citric acid, nitrilo tri-acetic acid, Alkali metal carbonates or sodium citrate. Zeolites X, Y and MAP are all considered suitable.

Polymeric components <B>A</B> number of polymeric components will typically be considered for use as part of compositions within the scope of the invention.

In particular the coating will preferably but optionally include a polymeric component.

<B>Of</B> the material printed, sprayed or otherwise deposited on the detergent surface a level of polymer from 0 to 70% may be used, preferably a polymer level of 0 to 50%, more preferably from I to 20%, most preferably from 5 to 15%.

Of any material 'in the bulk of the compostion suitable levels of polymer inclusion are between 0. 1 to 10% more preferably between 0.2 and 2% most preferably between 0.3 and 1.2%.

A variety of water soluble polymers may be added to perform variety of functions. For example as thickeners and anti scaling agents.

Suitable polymers include, Addition polymers - e.g. Poly Vinyl ; ethers, esters, amides, carboxylates, maleates, methacrylates, acrylates, alcohols, acetates, sulphonated polymers and amphoteric polymers and copolymers thereof. In particular block copolymers, homo polymer and copolymer prepared using vinyl carboxylates in combination with monomer selected from the group consisting of (meth)acrylonitrile, 2-trimethylsiloxyethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-trimethyl-siloxyethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-ethoxyethyl(meth)acrylate, sorbyl(meth)acrylate, butyl(meth)acrylate, ethyl (meth)acrylate, glycidyl (meth)acrylate, hexyl (meth)acrylate, hexyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, (meth)acrylonitrile, lauryl (meth)acrylate, methyl (meth)acrylate, octyl (meth)acrylate, p-tolyl (meth)acrylate, phenyl (meth)acrylate, propyl (meth)acrylate, sorbyl (meth)acrylate, and stearyl (meth)acrylate, may be used. Homo and block polymers of the above monomers are particularly suitable for use in the inks of the 'invention. Other suitable polymers include condensation polymers<B>-</B> eg Poly<B>;</B> esters, and urethanes, gelatin, xanthan gums, guar gum and alginates. Preferred molecular weights are from 5,000 to 100,000. More preferably from 10,000 to 30,000. Suitable polymeric materials known in the art are Hydrogenated caster oils (eg Croduret 50 ex Croda), acrylic acid polymers (eg ex National Starch) Acrylate maleate polymers (eg Sokolan CP-5 and CP- 10 ex BASF) and poly ethylene glycols (eg ex Hoechst), poly vinyl pyrrolidone (eg K50 ex ISP), Carbopol (ex 3V). Suitable levels of polymer inclusion are between 0. 1 to 10% more preferably between 0.2 and 2% most preferably between 0.3 and 1.2%.

<B>A</B> variety of substantially water insoluble polymers may be added to perform a varierty of functions for example soil release agents and tablet excipients. Eg polyoxyethylene terephthalate, polyethylene terephthalate and cellulose and its hydroxy alkyl and carboxy alkyl derivatives. Bleaches A bleaching composition may also be included. The preferred bleaching system for use in the invention comprises a hydrogen peroxide precursor compound and the bleach activator as known in the art which is capable of reacting with the hydrogen peroxide to generate a peracid.

The hydrogen peroxide precursor compound may, for example, be an inorganic persalt e.g. a perborate (in the monohydrate and/or tetra hydrate form), a percarbonate or a persulphate. The alkali metal salts of these compounds are preferred, particularly sodium and potassium salts. Alternatively in the case where the detergent formulation is in solid form, the bleaching agent may be a urea-hydrogen peroxide complex. In the case of a liquid formulation the hydrogen peroxide precursor compound may be hydrogen peroxide per se. Pre-formed per acids known in the art are also considered suitable.

Specific examples of bleach activator which may be used in the detergent formulations of the invention include tetra acetyl ethylene diamine, phthalimido peroxihexanoic acid eg Eureco ex Ausimont), hexa acetyl sorbitol, hexa acetyl mannitol, penta acetyl glucose and octa acetyl sucrose. Particularly preferred are hexa acetyl sorbitol and hexa acetyl mannitol which may be used in admixture, e.g. as disclosed in EP-A-0 <B>525 239.</B> Further examples are compounds having nitrogen atoms in the basic carbohydrate skeleton, e.g. the peracetylated forms of N-methyl gluxconamide, N-methyl glucamine and glucopyronosyl amine.

Chlorine bleaches may also be employed either as a hypochlorite, for example, an alkali metal hypochlorite or as a precursor compund such as Trichloro iso cyanuric acid, sodium dichloro isocyanurate and its di hydrate (eg Oxidan (tm) DCN/WSG ex Sigma). Such systems may be used in conjunction with a suitable catalyst for example as described in EP<B>937 772</B> (Procter). Effervescent systems An effervescent system may be employed. Suitable agents include a micxture of an acid and an alkali metal carbonate or bicarbonate, for exaple citric acid and sodium carbonate. Sodium percarbonate peroxohydrate (eg ex Eka chemicals) is also considered.

Clays <B>A</B> clay may be used in the composition, either per se or as a carrier for the perfume. The clay which is used in the formulation of the invention may be any one of the fabric softening clays having fabric softening properties used in laundry detergent formnulations. Such clays are generally of the "lamellar type" and are such that the layers "separate" to become deposited on the ganments being washed. The clay may for example be a Smectite such as a Laponite, Bentonite, Montmorrillonite, Hectonite or Saponite. For example, the clay may be a Sodium Montmorrillonite, a Sodium Hectorite, a Sodium Saponite, a Calcium Montmorrillonite or a Lithium Hectorite.

Softener components The term "fabric softening agent" as used herein includes cationic, and nonionic fabric softeners used alone and also in combination with each other. A preferred fabric softening agent of the present invention is a mixture of cationic and nonionic, fabric softeners. (i) Fabric Softening Agents Examples of fabric softening agents that are especially useful in the substrate articles are the compositions described in U.S. 4,103,047, 4,237,155, 3,686,025, 3,849,435 and U.S. 4,073,996, said patents are hereby incorporated herein by reference. Another preferred type of fabric softener is described in detail in U.S. 4,661,269, Toan Trinh, Errol H. Wahl, Donald M. Swartley and Ronald L. Hemingway, issued Apr. 28, 1987, said patent being incorporated herein by reference. Examples of nonionic fabric softeners are the sorbitan esters, C12 to C26 fatty alcohols, and fatty arnines described herein. More biodegradable fabric softener compounds can be desirable. Biodegradability can be increased, e.g., by incorporating easily destroyed linkages into hydrophobic groups. Such linkages include ester linkages, ainide linkages, and linkages containing unsaturation and/or hydroxy groups. Examples of such fabric softeners can be found in U.S. 3,408,361, 4,709,045, 4,233,451, 4,127,489, 3,689,424, 4,128,485, 4,161,604, 4,189,593, 4,339,391, said patents being incorporated herein by reference.

Enzymes An enzyme may be included in the composition. The enzyme may, for example, be a protease, amylase, lipase or cellulase (or mixtures thereof) such as commonly used in detergent formulations. Examples of suitable enzymes are available under the names Opticlean (tm), Savinase (tm), Esperase (tm); Termamyl (tm), Maxamayl (tm), Lipomax (tm), Lipolase (tm); Celluzyme (tm) and Carezyme (tm). The amount of enzyme incorporated in the formulation will depend on activity but will typically be<B>0. 1</B> to<B>3%.</B> This level is particularly suitable for Savinase 6.OT, Termamyl <B>60T,</B> Celluzyme <B>0.7T</B> and Lipomax.

It will be appreciated that the formulation may incorporate additional components as conventionally included in a hard surface cleaner, laundry detergent, fabric refresher, fabric conditioner or similar product.

For a laundry detergent formulation it will be appreciated that the formulation may incorporate additional components as conventionally included. One example of such an additional component is a soap which may be used in an amount up to<B>5% by</B> weight as a processing aid. Particularly preferred are those with<B>C 8</B> to<B>C22</B> alkyl chains, more preferably<B>C</B> 12 to<B>C</B> 12 alkyl and with an iodine value less than<B>5</B> more preferably less than<B>1.</B> Mono, di and trifimctional acids are not without the scope of the invention. Particularly suitable are the Prifac (TM) and Pristerine (TM) materials supplied<B>by</B> Uniquema. Further examples include anti-foam agents, sequestrants (e.g. of the phosphonate type), whiteness maintenance agents (e.g. CMC, polyoxyethylene terephthalate, polyethylene terephthalate), colourants (e.g. dyestuffs), perfume, flow control agents (e.g. a sulphate) flow enhancer (e.g. a zeodite), pH regulators (e.g. a carbonate or bicarbonate), anti-corrosion agents, dye transfer inhibitors (e.g. PVP) and optical brighteners (e.g. Tinopal CBS-X and Tinopal DMS-X). These components may, for example, each be present in amounts up to 1% by weight of the formulation. Perfumes A perfurme will typically be formulated in a product using the invention. The perfume ingredients and compositions of this invention are the conventional ones known in the art. Selection of any perfume component, or amount of perfume, is based on aesthetic considerations. Examples of suitable perfume compounds and compositions can be found in US 4,145,184, Brain and Cummins, US 4,209,417, Whyte, US 4,515,705, Moeddel and 4,152,272, Young, all of which are patents being incorporated herein by reference.

Many suitable of the perfume ingredients with their odour characters, and their physical and chemical properties, such as molecular weight and boiling point, are given in "Perfume and Flavour Chemicals (Aroma Chemicals)," Steffen Arctander, 1969, publ., Steffen Arctander incorporated herein by reference. Examples of the highly volatile, low boiling, perfume ingredients are: anethole, benzaldehyde, benzyl acetate, benzyl alcohol, benzyl formate, iso-bornyl acetate, camphene, cis-citral (neral), citronellal, citronellol, citronellyl acetate, para-cymene, decanal, dihydrolinalool, dihydromyrcenol, dimethyl phenyl carbinol, eucalyptol, geranial, geraniol, geranyl acetate, geranyl nitrile, cis-3-hexenyl acetate, hydroxycitronellal, d-limonene, linalool, linalool oxide, linalyl acetate, linalyl propionate, methyl anthranilate, alpha-methyl ionone, methyl nonyl acetaldehyde, methyl phenyl carbinyl acetate, laevo-menthyl acetate, menthone, iso-menthone, myrcene, myrcenyl acetate, myrcenol, nerol, neryl acetate, nonyl acetate, phenyl ethyl alcohol, alpha-pinene, beta-pinene, gamma-terpinene, alpha-terpineol, beta-terpineol, terpinyl acetate, and vertenex (para-tertiary-butyl cyclohexyl acetate). Some natural oils also contain large percentages of highly volatile perfume ingredients. For example, lavandin contains as major components: linalool; linalyl acetate; geraniol; and citronellol. Lemon oil and orange terpenes both contain about 95% of d-limonene. Examples of moderately volatile perfume ingredients are: amyl cinnamic aldehyde, iso-amyl salicylate, beta-caryophyllene, cedrene, cinnamic alcohol, cournarin, dimethyl benzyl carbinyl acetate, ethyl vanillin, eugenol, iso-eugenol, flor acetate, heliotropine, 3-cis-hexenyl salicylate, hexyl salicylate, lilial (para-tertiarybutyl-alpha-methyl hydrocinnamic aldehyde), gamma-methyl ionone, nerolidol, patchouli alcohol, phenyl hexanol, beta-selinene, trichloromethyl phenyl carbinyl acetate, triethyl citrate, vanillin, and veratraldehyde. Cedarwood terpenes are composed mainly of alpha-cedrene, beta-cedrene, and other C.sub.15 H.sub.24 sesquiterpenes. Examples of the less volatile, high boiling, perfume ingredients are: benzophenone, benzyl salicylate, ethylene brassylate, galaxolide <B>(1,3,4,6,7,8-</B> hexahydro- 4,6,6,7,8,8- hexamethyl-cyclo-penta-gama-2-benzopyran), hexyl cinnamic aldehyde, lyral (4<B>-</B> (4 - hydroxy-4-methyl pentyl) <B>- 3 -</B> cyclohexene <B>- 10 -</B> carboxaldehyde), methyl cedrylone, methyl dihydro jasmonate, methyl-beta-naphthyl ketone, musk indanone, musk ketone, musk tibetene, and phenylethyl phenyl acetate. Such components are particularly preferred constituents of any perfume composition used in the invention.

Bactericide <B>A</B> bactericide may be optionally included in the detergent product or the external carton packaging. Compositions containing bactericide will contain from 5 to 0.0001% bactericide, virucide or anti-microbial agent, preferably from 2 to 0.001%, more preferably from I to 0.005% most preferably from 0.1 to 0.01%. Biocides as listed in annex I of the Biocidal Products Directive of the EC. are considerec particularly suitable. Such materials may be used in combination, when used in combination such bactericidal, virucidal or anti-microbial agents will each be present at a level of from 5 to 0.00003% bactericide, virucide or anti-microbial agent, preferably from 3 to 0.0001%, more preferably from I to 0.0001% most preferably from 0.1 to 0.001%.

Most preferred are bactericidal agents which are single organic molecules with a molecular weight above 250. Not wishing to be bound by theorey such molecules possess lower potential for human toxicity by virtue of their higher molecular weigh and absence of inorganic materials. Disintegrants A disintegrant may also be included, for example to aid powder and tablet dispersability. Most preferably any disintegrant is a cellulose based material. Such cellulose based material may for example comprise both crystalline and amorphous cellulose. Examples of suitable materials are disclosed, for example, in WO-A-9855575 (Henkel), WO-A-9840462 (Herzog). The cellulose may be a cross-linked modified cellulose e.g. AC-DI-SOL and/or may comprise micro crystalline cellulose fibres (e.g. HANFLOC). The cellulose based material may be a cellulose derivative which may be cross-linked, e.g. a cross-linked carboxymethyl cellulose.

The disintegrant may be a cellulose derivative, for example a sodium carboxymethyl cellulose. Examples include CORALOSE and NYMCEL. A particularly suitable disintegrant for use in the invention is available under the trade mark NELYN. (ex FMC, grade LX16 which is ail internally cross-linked carboxymethyl cellulose.

Further examples of disintegrants which may be used include various starches such as potato, rice, com ore maize starch. The disintegrant may be a starch derivative, e.g. carboxymethyl starch such as available under the trade mark PRIMOGEL or a sodium starch glycolate such as available under the trade mark EX2LOTAB.

It is also possible for the disintegrating agent to be a clay. Such clays are generally of the "lamellar type" and may for example be a smectite such as a Laponite, Bentonite, Montmorrillonite, Hectorite or Saponite. For example, the clay may be a Sodium Montmorrillonite, a Sodium Hectorite, a Sodium Saponite, a Calcium Montmorrillonite or a Lithium Hectorite.

Furthermore, it is possible for the disintegrating agent to be a synthetic polymer, for example a cross-linked polyvinyl pyrrolidone, POLYPLASDONE XL or KOLLIDON XL. Additional optional components The detergent used in the invention may also contain an optical brighteners or fluorescer. For example Tinopal CBS-X (disodium 2,2-bis-(phenyl-styryl)sisulphonate and Tinopal DMS-X (4,4'bis <B>-</B> (2-morpholino-4-anilino-s-triazin-6-ylamino) stilbene disulphonate) and the various possible alkali metal salts thereof particularly the potassium salts. Methods of applying the colourant Any method of applying the colourant is within the scope of the invention, for example, Transfer printing, Screen printing, lithographic printing, dot matrix printing, brushing, daubing, contact printing methods and spraying as non limiting examples. The preferred methods do not involve contact, save between the ink and the surface being printed, for example as obtained by spraying. A particularly preferred method is Ink jet printing. Ink Jet Printing Ink jet printing is accomplished by ejecting ink from a nozzle toward paper or another print medium. The ink may be driven toward the medium in a variety of ways. For example, in electrostatic printing, the ink is driven from a nozzle toward a medium by an electrostatic field. Another ink jet printing procedure, known as squeeze tube, employs a piezo-electric element in the ink nozzle. Electrically-caused distortions of the piezo-electric element pump the ink through the nozzle and toward the print medium. In still another ink jet printing procedure, known as thermal or bubble ink<B>jet</B> printing, the ink is driven from the nozzle toward the print medium by the formation of an expanding vapor phase bubble in the nozzle. These various printing methods are described in "Output Hard Copy Devices," edited by Durbeck and Sherr, Academic Press, 1988 (especially ch 13, "Ink Jet Printing").

Ink-jet printing is as non-impact printing process in which droplets of ink are deposited on a print medium in a particular order to form alphanumeric characters, area fills, and other patterns thereon. Low cost and<B>high</B> quality of output, combined with relatively noise-free operation, have made ink-jet printers a popular alternative to other types of printers used with computers. The non-impact printing process of ink-jet printing involves the ejection of fine droplets of ink onto a print media such as paper, transparency film, or textiles in response to electrical signals generated<B>by</B> a microprocessor. There are two basic means currently available for achieving ink droplet ejection in ink-jet printing: thermally and piezoelectrically. In thermal ink-jet printing, the energy for drop ejection is generated<B>by</B> electrically-heated resistor elements, which heat up rapidly in response to electrical signals from a microprocessor to create a vapor bubble, resulting in the expulsion of ink through nozzles associated with the resistor elements. In piezoelectric ink-Jet printing, the ink droplets are ejected due to the vibrations of piezoelectric crystals, again, in response to electrical signals generated<B>by</B> a microprocessor.

The printed image produced<B>by</B> an ink Jet printer, as in most printing processes, consists of discrete dots. However, such dots may produce a continuum of coverage and therefore their origin as individual dots is not limiting.

Colourants Any suitable colourant may be used in the invention, particularly those which adsorb light between<B>180</B> and 500nm. Notwithstanding, the following describes preferable colourants and compositions.

Classes and principles of preferred colourant systems In conunercially-available thermal ink-jet color printers, such as the DeskJet.reg. printer available from Hewlett-Packard Company, a color spectrum is achieved by combining cyan, magenta, and yellow inks in various proportions. A four-pen set including the three primary color inks and a black ink is typically employed in such printers to achieve the necessary color combinations. The cyan, magenta, and yellow inks derive their hues from cyan, magenta, and yellow colorants, respectively.

Colorants for inks are available in the form of dyes or pigments. Accordingly, ink-jet inks are available as either dye-based or pigment-based compositions. Of the two, dye-based ink-jet ink compositions are much more widely available. However, it has been found that for the puposese of this invention pigmentatious and polymeric dye based inks are preferred. Dye-based ink-jet ink compositions are generally aqueous-based and are formulated by dissolving dye in an ink vehicle. The dye molecules employed in ink-jet ink compositions are often in the form of dye salts made of a dye anion and a cation such as sodium or tetramethylammunium (TMA). A limited number of pigment-based ink-jet inks are also available, which generally comprise a pigment dispersed in an aqueous solution by a dispersant. Although pigments offer the very desirable properties of waterfastriess and lightfastriess Specific colourant materials Specific dyes within the scope of the invention and preferably used therein.

<B>A</B> water soluble<B>dye</B> system characterized in that the dye system comprises a dye selected from the group consisting of :

1. Quinoline Yellow 70 with color index no. 47005; 2. Tartrazine XX90 with color index no. 19140; 3. Orange RGL90 with colorindex no. 15985; 4. Ponceau. 4RC82 with color index no. 16255; 5. Blue AE85 with color index no. 42090; 6. Patent Blue V85N50 with color index no. 42051 ; and It will be appreciated that the foregoing is a limited list of preferble dyes and that other similar materials farnilliar to the colourist skilled 'in the art may be used.

Polymeric colourants Such materials are particularly prefered as, not wishing to be bound by theorey, they exhibit lower smudging on storage which is understood to be exacebated <B>by</B> surfacatsnt and so the beneficial use is specific to or exemplified by detergent compositions.

Polymeric Coulourants Supplier Liquitint (tm) blue <B>710230</B> Milliken Liquitint (tm) yellow <B>EC</B> 710406 Milliken Liquitint (tm) blue <B>710407</B> Milliken Liquitint (tm) violet <B>PG 710233</B> Milliken Liquitint (tm) red RL <B>710208</B> Milliken The above coloarants and mixtures thereof are within the scope of the invention. Specific pigments Pigmentatious colourants are a particularly preferred method of colourantion and, not wishing to be bound by theorey, are particualy chemically stable and resistant to smudging or other diffusive processies which reduce their effectiveness and moreover are specific to or exemplified by detergent compositions.

Representative commercial dry pigments that may be selected to advantage are:

Pigment Brand Name Supplier Colour Index BK 8200 Paul Uhlich Black 7 Chromophtal (tm) Yellow 3G Ciba-Geigy Yellow 93 Chromophtal (tm) Yellow GR Ciba-Geigy Yellow 95 Chromophtal (tm) Yellow 8G Ciba-Geigy Yellow 128 Dalamar (tm) Yellow YT-858-D Heubach Yellow 74 Hansa Yellow RA Hoechst Yellow 73 Hansa Brilliant Yellow 5GX-02 Hoechst Yellow 74 Hansa Brilliant Yellow I 0GX Hoechst Yellow 98 Hansa Yellow X Hoechst Yellow 75 Heliogen (tm) Blue K 7090 BASF Blue 15:3 Heliogen (tm) Blue L 7101F BASF Blue 15:4 Heliogen (tm) Green K 8683 BASF Green 7 Heliogen (tm) Blue NBD 7010 BASF Heliogen (tm) Green L 9140 BASF Green 36 Heliogen (tm) Blue L 6901F BASF Blue 15:2 Heucophthal (tm) Blue G Heubach Blue 15:3 Hostaperm (tm) Scarlet GO Hoechst Red 168 Hostaperm (tm) Yellow H4G Hoechst Yellow 151 Hostaperm (tm) Yellow H3G Hoechst Yellow 154 Hostaperm (tm) Orange GR Hoechst Orange 43 Indofast (tm) Violet Mobay Violet 23 Indofast (tm) Brilliant Scarlet Mobay Red 123 Irgalite (tm) Rubine 4BL Ciba-Geigy Red 57:1 Irgazin (tm) Yellow 5GT Ciba-Geigy Yellow 129 L74-1357 Yellow Sun Chem. L75-1331 Yellow Sun Chem. L75-2377 Yellow Sun Chem. Monastral (tm) Violet R Ciba-Geigy Violet 19 Monastral (tm) Violet Maroon B Ciba-Geigy Violet 42 Monastral (tm) Magenta Ciba-Geigy Red 202 Monastral (tm) Scarlet Ciba-Geigy Red <B>207</B> Monastral (tm) Red B Ciba-Geigy Violet <B>18</B> Novoperm (tm) Yellow <B>FGL</B> Hoechst Yellow <B>97</B> Novoperm (tm) Yellow HR Hoechst Yellow <B>83</B>

Paliogen (tm) Orange BASF Orange 51 Paliogen (tm) Blue L 6470 BASF Blue 60 Permanent Yellow NCG-71 Hoechst Yellow 16 Permanent Yellow G Hoechst Yellow 14 Permanent Yellow GR Hoechst Yellow 13 Permanent Yellow GG Hoechst Yellow 17 Permanent Yellow G3R-01 Hoechst Yellow 114 Permanent Rubine F6B Hoechst Red 184 Permanent Yellow DHG Hoechst Yellow 12 Quindo (tm) Red R6713 Mobay Quindo (tm) Red R6700 Mobay Quindo (tm) Magenta Mobay Red 122 Raven (tm) 1170 Col. Chem. Black 7 Special Black 4A Degussa Black 7 Sterling (tmn) NSX 76 Cabot Black 7 Sterling (tm) NS Black Cabot Black 7 Tipure (tm) R-101 Du Pont Particularly suitable commercial dry pigments are: Auric Brown (C.I. Pigment Brown 6) Carbon black Dalamar (tm) Yellow YT-839-P (Pigment Yellow 74, C.I. No. 1174 1) Graphite Hansa (tm) Yellow (Pigment Yellow 98) Heucophthal (tm) Blue BT-585-P Indo (trn) Brilliant Scarlet (Pigment Red 123, C.I. No. 71145) Magenta RV-6831 presscake (Mobay Chemical, Haledon,N.J.) Permanent Rubine F6B 13-1731 (Pigment Red 184) Pigment Scarlet (C.I. Pigment Red 60) Quindo (tm) Magenta (Pigment Red 122) Sunbrite (tm) Yellow 17 (Sun Chemical Corp, Cincinnati, Ohio) Sunfast (tm) Magenta 122 (Sun Chemical Corp., Cincinnati, Ohio) Toluidine Yellow G (C.I. Pigment Yellow 1) Toluidine Red B (C.I. Pigment Red 3) Toluidine Red Y (C.I. Pigment Red<B>3)</B> Watchung (tm) Red B (C.I. Pigment Red 48) Black pigments, such as, Carbon black generally are not available in the form of aqueous presscakes, but such a form is not excluded from te scope of the invention.

The above colourants and mixtures thereof are within the scope of the invention. Metallic ink<B>j</B>et inks F mie particles of metal or metal oxides also may be used to practice the invention. For example, metal and metal oxides are suitable for the preparation of magnetic inkjet inks. Fine particle size oxides, such as silica, alumina, titania, and the like, also may be selected. Furthermore, finely divided metal particles, such as copper, iron, steel, aluminum and alloys, may be selected for appropriate applications.

The above colourants and mixtures thereof are within tile scope of the invention. Additional colourant components and adjuncts To form a dye, ink or other formulated colourant composition using the aforementioned basic colourstuffs it will be usual to add additional components. Any conventional adjunct as would be considered by the person skilled in the art is considered within the scope of the invention. However, particularly preferred materials are as follows.

Polymeric carrier component <B>A</B> segment of said block copolymer is a homopolymer or copolymer prepared from at least one monomer selected from the group consisting of methacylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, lauryl methacrylate, stearyl methacrylate, phenyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, 2-ethoxyethyl methacrylate, methacrylonitrile, 2-trimethylsiloxyethyl methacrylate, glycidyl methacrylate, p-tolyl methacrylate, sorbyl methacrylate, acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, lauryl acrylate, stearyl acrylate, phenyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate acrylonitrile, 2-trimethyl-siloxyethyl acrylate, glycidyl acrylate, p-tolyl acrylate, and sorbyl acrylate. Maleic acid and itaconic acid and thier correponding esters of are also considered suitable.

Further formulation principles Colourants in conj unction with materials to formulate inks would be chosen by the person skiled in the art. However, for their use in the detergents firled the following principles olf composition describe materials particularly, preferably, within the scope of the invention. Ink compositions used in ink Jet printers generally comprise delonized water, a water-soluble or water-miscible organic solvent, and a colorant.

The formulator of suitable inks for detergents use will also be guided<B>by</B> the prior art wherein various polymeric dispersants and camers are further described.

U.S. <B>5,180,425,</B> describes inkjet ink compositions which include an aqueous carrier medium, <B>I</B> ht to provide a pigment dispersion, and a polyol/alkylene oxide cosolvent. These inks are taug long functional life to inkjet printers and to resist film fort-nation. Liponic EG- <B>1</B> is one of the preferred cosolvents disclosed. Other optional solvents which may<B>be</B> used in the described invention include polyethylene glycol. U.S. <B>5,302,197,,</B> describes aqueous ink jet ink compositions which comprise a pigment dispersion, an aqueous carrier medium, and a cosolvent mixture which includes a polyol/alkylene oxide condensate together with a cyclic amide derivative. Liponic EG-1 is taught to be useful as the polyol/alkylene oxide condensate component. EP<B>603,469,</B> describes ink jet inks comprising an aqueous carrier medium, specifically-defined alkyl polyol ether cosolvents, and a pigment dispersion (pigment particles stabilized<B>by</B> a dispersant). These inks are taught to provide a good balance of viscosity, surface tcrision, resistance to nozzle pluggage, print quality, light stability and smear and water resistance. The solvents which may be used in the disclosed invention include 1,2,3-butanetriol. U.S. 4,597,794, describes an ink formulation used in ink jet printing processes which is said to form a clear image and have good physical properties. Specifically disclosed solvents for use in the ink include polyethylene glycol and 1,2,6-hexanetriol.

it has now been discovered that the use of a very specific cosolvent mixture containing<B>C2</B> to C8 terminal alkanediol or mixture thereof together with either (a) a low molecular weight polyethylene glycol or related compound or (b) a polyol/alkylene oxide condensate, in an aqueous ink composition containing a dispersion of an insoluble pigment, provides a unique blend of optimized properties. Specifically, these compositions provide excellent properties in terms of stability, optical density (even when low levels of pigment are utilized), viscosity, printing characteristics (water-fastness, minimized feathering, minimized running of ink on the printed page), and printer maintenance problems (i.e., minimized clogging of the printerjets during gaps in printer usage).

Detergent tablets Detergent tablets are a particularly presferred product form for use in the invention. Tablets are known in the art and any suitable method of preparation is within the scope of the invention. As used herein the term tablet refers to a non particulate solid, which may be a bar, block, shaped body, bnick, briquette, cake or tablet.

Particularly preferred are tablets formed by the compression of a particulate paterial.

A pressure of 100 kPa to 1000 MPa will generally be suitable for forming the tablet. More preferably, a pressure of 200 kPa to 100 MPa is used and even more preferably one of 25 OkPa to 10 MPa, most preferably from 300 kPa to 5000 kPa.

There are a number of models of tableting press which are capable of producing dual layer tablets, for instance the "Excelapress" and "Rotapress" models are produced<B>by</B> BWI Manesty of Liverpool. It is also possible to modify a single layer press to produce dual layer tablets, for instance an RS model, also ex Manesty, could be modified in this way. Other examples are the PH400 series ex Korsch of Berlin, the<B>3090</B> series ex Wilhem Fette of Hambury or model MOD BR680 ex<B>J.</B> Bonal S.A., Barcelona.

Tableting presses generally work<B>by</B> having a rotating circular turret with arrays of punches which compress the tablets from above and below. The cycle consists of filling the die with the powder which will make up one of the layers, optionally followed<B>by</B> filling with the powder of the second layer, compression of the tablet, and release.

Machines specially designed for dual layer operation usually have a small amount of pre- compression between filling the die with the powders of the first and second layers. This gives a sharper definition between the two layers which may be more aesthetically pleasing, particularly<B>if</B> the layers are of different colours.

The tableting press should be equipped with a feed mechanism so that the two powders are fed into the die in the weight ratio desired. Excess powder is removed from the area of the die<B>by</B> means of scrapers. The press should allow the tablet thickness to be adjustable. For a given die/punch size, this allows the tablet weight to be regulated.

The press should also have a control to regulate the applied force used in the main compression. The applied pressure should typically be about 0.2 to 50 NMPa, which for a 20 gram tablet would translate to an applied force per tablet of about 0. 18 to 45 kN. The pressure applied is a crucial part of the tableting operation as inadequate pressure will give a tablet which is not robust enough to withstand handling, while excess pressure gives a tablet which dissolves too slowly. The tablet strength may be monitored<B>by</B> use of equipment to measure its breaking strength under compression, such as the Holland CT5 automatic compression tester. The tablet is placed so that its smallest two opposite faces are placed between the compression bars. A 50 gram tablet should break at about 15-150 kg applied force, as applied by pseudo static compressive breaking force between flat faced, parallel opposed anvils or circular cross section of<B>I</B> cm square which corresponds to about<B>500-5000</B> kPa. Such a measure can conveniently be taken using a Holland CT5 automatic compression tester.

Tablets produced in accordance with the invention will generally consist of a single layer or only the first and second layers as discussed above although we do not preclude the possibility of additional layers being present. The tablet may, for example, comprise the second layer sandwiched between two of the first layers. Each of the first and second layers will, in the depth dimension of the tablet, generally have a thickness considerably less than the other two dimensions so that in a two layer tablet the individual layers have major faces injuxtaposed face- to-face relationship. The first and second layers may, for example, have a major face of circular or rectangular shape. The tablet may typically weight about<B>20g</B> to<B>60g</B> and if desired the first and second layers may be differently coloured.

Therefore whilst the invention relates to a product with a colourant applied as described it<B>Is</B> considerd appropriate and even advantagious to combine such coating with a homogeniously coloured tablet or portion thereof particularly when the tablet is therefore seen to change appearance when the external layer is removed.

Capsules are also within the scope of the invention. <U>Examples</U> The invention is illustrated using the following non limiting examples.

<U>omposition <B>I</B> (Automatic dish washing composition)</U> RAW MATERIAL % byweight Sodium Tripolyphosphate to 100% Sodium Disilicate Heavy Gran 25.0 Granular Sodium Carbonate 8.40 Sodium Perborate monohydrate 12.5 Polyvinyl pyrrolidone MW 25,000 5.0 50% solution Dequest 2016D 0.40 Benzotriazole 0.20 Polyethylene Glycol 0.20 TAED 3.00 Synperonic LF/RA 260 3.00 FGlycerol triactete 6.00 The composition was mixed to form a homogeneous powder using a low shear mixing process (Lodige ploughshare horizontal mixer) for 5 minutes. The mixture was then compressed in to tablets of 36mm long by 26mm wide and weighing 20grammes at the pressure indicated.

The encapsulating material used was a cross linked polyacrylate.

omposition 2 (Textile washing composition) RAW MATERIAL % by weight SODIUM TRIPOLYPHOSPHATE 32% LIGHT SODIUM CARBONATE To 100% PERBORATE TETRA HYDRATE 22% SODIUM CARBOXY METHYL CELLULOSE 2% TINOPAL DMS-X (FLUORESCER) 0.2% TINOPAL CBS (FLUORESCER) 0.1% PROTEASE ENZYME 0.7% AMYLASE ENZYME 0.7% CELLULASE ENZYME 0.7% POLY DIMETHYL SILOXANE 0.4% SODIUM SILICATE 2% TETRA ACETYL ETHYLENE DIAMINE 3% 7EO ALKYL ETHOXYLATE 5% SODIUM ALKYL <B>BENZENE SULPHONATE 10%</B> 40% <B>SODIUM</B> SILICATE <B>SOLUTION</B> (BINDER) 12% PERFUME <B>0.5%</B> The silicate is sprayed on to the powder whilst mixing under low shear in a Lodige ploughshare mixer to give a granular powder for agglomeration. This was then tableted at the specified pressure to form a tablet of 44mm diameter and 50g weight.

Composition<B>3</B> Example of isotropic liquid detergent: preferred composition

Raw material % by weight Propylene glycol To 100% C 1 3/C 15 fatty alcohol with 7 EO (1) 12.60 C I 3/C 15 fatty alcohol with 3 EO (2) 9.00 Mono ethanolamine 9.60 Dodecyl benzene sulphonic acid 97% (3) 25.20 Fatty acids blend (4) 18.00 Denaturated ethyl alcohol 94% 4.26 Protease enzyme (5) 2.00 Sodium phosphonate (6) 3.50 O.B.A. (7) 0.50 Denathonium benzoate 2.5%. (8) 0.01 Dye C.I. 42051 blue Trace Fragrance Trace The above composition after thorough mixing and degassing was encapsulated in a lmrn thick coating of 80% hydrolysed polyvinyl acetate. This material contained 3% titanium dioxide powder (ex Aldrich) to provide opacity. Each spherical capsule contained I OOg of liquid.

In Summary - Unit dose Composition 1 A dishwasher tablet Composition 2<B>A</B> textile washing tablet Composition<B>3</B> An capsule

Ink <B>I</B> Component Level Carbon black 3% Methacrylic acid, Stearyl methacrylate 0.75% copolymer Polyethylene glycol (mw <B≥</B> 400) 14% 1,3-propanediol <B>6%</B> Deionised water to <B>100%</B> <B><U>I</U></B>

Ink 2 Component Level Heucophthal tin Blue G, XBT-583D 20% (Pigment, ex Heubach, Inc., Newark, NJ) Methacrylic acid, Methyl methacrylate co 10% Polymer Diethylene glycol 41% Deionized water to 100% Ink <B>3</B> Component Level Heucophthal tm Blue G, XBT-583D 20% (Pigment, ex Heubach, Inc., Newark, NJ) Methacrylic acid, Methyl methacrylate co 0% Polymer Diethylene glycol 41% Deionized water to 100% Ink 4 Component Level Heucophthal tm Blue G, XBT-583D 20% (Pigment, ex Heubach, Inc., Newark, NJ) Methacrylic acid, Methyl methacrylate co 10% Polymer Diethylene glycol 41% Deionized water to 100% Ink <B>5</B> Component Level Blue AE85 with color index no. 42090 18% Methacrylic acid, Methyl methacrylate co Polymer 10% Diethylene glycol Deionized water 41% to <B>100%</B> In summary - Inks Ink I - Carbon black Ink 2 - Pigmentatious Ink 3 - Pigmentatious, with polymer Ink 4 - Polymeric colourant Ink 5 - Dye The compositions were prepared using an ultraturrox (tm) high speed mixer and used shortly after use to avoid stability issues.

<U>Testing methodology</U> Two lines of ink, 5mm appart edge to edge and 5mm wide were jetted on to the appropriate substrate.

The width of substrate left in its original colour is recorded as 'diffusion band width'. The lower this figure the greater diffusion had occurred.

The intensity of the colour of the printed stripe as measured before and after storage. The change as a percentage decrease in intensity was recorded. Due to the differences in wavelength of adsorbance and intensity of the dyes this enables some comparison to be made.

The colour of the lines was measured using a McBeth Colour Eye 3 100 colounimeter using the CIElab L, a,<B>b</B> (CIE<B>1976)</B> colour space measurements. The difference in the colour in terms of delta<B>E</B> ab* (i.e. the square root of the sum of the squares of the differences in the L, a and<B>b</B> measures before and after the use of the product). was then determined for an area of the sheet. Results were rounded to the first decimal. Each reading was an average of five separate readings. The samples were storted at<B>37C</B> and<B>50%</B> relative humidity for four weeks.

D) i ffu s i o n bmd width Ink Comp. I Comp.2 Comp. 3 1 4.75 4 .5 4 .5 2 4.5 4.0 4.0 3 4.75 4 .5 4.5 4 4.5 4.75 5.0 5 3.5 3.0 3.75 This data shows that the polymeric and pigmentatious inks are preferred.

<U>Percentage fading</U> Lower is better lak Comp. I Comp.2 Comp. 3 1 2%a 3%D 4% 2 5y, so8% 7%Z 3 5% 7% 7%Z 4 1D2% 1d% 5% 5 21% 281a 90/. This data shows that the pigmem*tatious Inks are preferred.

Claims (4)

1. <U>Claim</U> 1) A method of applying a surface coating to a detergent material using by the printing of a pigment ink.
2. 2) A method as described in claim I wherein the printing method is an Ink Jet printing method.
3. 3) A method as described in claim I wherein the detergent material is predominantly solid. 4)<B>A</B> method as described in claim<B>3</B> wherein the detergent material is a tablet of compressed detergent powder. 5) A method as described in claims 2 and
4. 4. <B>6) A</B> method as described in claim<B>5</B> wherein the ink is predominantly based upon pigmentatious colourants. <B>7) A</B> method as described in claim<B>5</B> wherein the ink includes a polymeric colourant. <B>8) A</B> method as described in claim<B>I</B> wherein the detergent material contamins more than<B>1%</B> surfactant. <B>9) A</B> method according to claims<B>1</B> wherein a detergent tablet is printed using conventional printing processies using an ink containing from<B>I</B> to<B>50%</B> polymer and ans at least one organic <B>dye</B> or inorganive pigment. <B>10) A</B> detergent tablet with a printed surface coating for use in domestic laundry.