GB2364064A - Surface modification of detergents - Google Patents

Abstract

A method of laser marking of solid materials composed of organic / inorganic mixtures, particularly detergents is disclosed whereby improved definition, light and storage stability compared to the use of dyes or dyes alone was observed. The method is particularly suitable for detergents tablets where reduced wicking of surfactant from solids surfaces so treated was also observed.

Description

2364064 Surface modification of detergents The present invention relates

to a method of surface modification of solid or substantially solid detergents articles to give either complete or partial surface modification.

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.

The addition of colour is largely inefficient as dye is distributed throughout the product and in a detergent formulation the surfactants present readily solubilise the dyes and lead to their diffusion This is due to the nature of detergent systems which are designed to solubilise organic materials and particulate materials (i e dirt and soils) to which dyes are closely related Colourant systems therefore have a tendency to be distributed by 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 (c f UK trademark applications 2,149,344, 2,165,230 (Benckiser) by example) In addition, in practice changing colours is time consuming requiring a thorough 'clean-down' of production plant.

Alternatively on larger detergents articles such as soap bars, laundry detergent tablets and the like it is common to make an embossed article in which the embossing gives a visual representation of significance to the consumer, or which reinforces an attribute of the tablet.

The embossing of solid products is typically performed as part of a single extrusion or compressive action which forms the whole shape of the article In compression the punches used are embossed with the reverse image, this obviously increases the surface area of the punches which exacerbates the issue of sticky detergents material adhering to the punches (or dies) and slowing production Whilst methods to alleviate this, for example low temperature die cooling for soaps and rubberised coatings (e g WO 98 /46720, Lever) are well known they add cost and/or reduce the definition available by such methods which is typically low even with metal punches.

In addition changing designs is time consuming and expensive.

The subject of the present invention is a method which overcomes or avoids the aforementioned disadvantages The present invention provides a controlled high intensity laser beam to modify the detergents surface.

2 The prior art widely discloses the use of lasers for the selective modification of plastics packaging materials, for example in date coding (e g Videojet Int, 'Print Source' issue 19, 1999) and is more generally disclosed for the marking of products in (CN 1216270, Uni Cent China) Lasers are also known for the partitioning of dough in to discrete units and the cutting of shapes (EP 930012) and are similarly known for cutting textiles The use for surface decoration of buttons is disclosed in (EP 856 421, SRL) The application of lasers to tablets and inorganic (non metallic) substrates is not disclosed save in the surface activation of rare earth metals on calcium fluoride tablets and is disclosed in (RU 2 098 448, Phys Tech Inst USSR).

Minimum exposure times of 5 seconds at rates of not more than 100 cm/second are clearly out with the parameters suitable for use with products containing organic materials.

The art is limited to the use of carbon dioxide lasers on organic or inorganic substrates and the benefits of surface modification of materials comprising mixtures of organic and inorganic materials, particularly detergents materials is not disclosed.

According to one aspect of the present invention there-is provided the use of high intensity coherent electromagnetic radiation source or sources in the ultra-violet to infra red wavelength range for the surface modification of solid or substantially solid product compositions comprising a predominant mixture or organic volatalisable materials and inorganic, non-metallic substantially non-volatile materials The compositions may include subsidiary amounts of non-volatile organics materials which may be volatalised on decomposition, for example polymers and inorganic materials includes those which may be decomposed on heating, for example carbonates and bicarbonates The surface modification on irradiation referred to may be chemical, physically or both and is preferably a visually perceivable change.

Non-metallic materials includes metal salts but does not include metals as such.

Organic materials are those based primarily on carbon, hydrogen, nitrogen and oxygen.

According to a particularly preferred embodiment of the invention the 'high intensity coherent electromagnetic radiation source' is a carbon dioxide laser, and the 'solid or substantially solid product compositions comprising a predominant mixture or organic volatalisable materials and inorganic, non-metallic substantially non-volatile materials which may or may not be chemically changed on irradiation' is a detergent article.

According to a further aspect of the invention the light source of the invention is controlled by a computer which modifies an acousto optical crystal or electro optical crystal or similar to manipulate the light so as to produce a surface modification which conveys information.

According to a yet further aspect of the invention the light source of the invention is used to remove colouration from an already coloured object of the types described so as to produce a visible surface modification.

3 According to a further aspect of the invention there is provided an the use of high intensity coherent electromagnetic radiation source in the ultra- violet to infra red wavelength range for the surface modification of solid or substantially solid product compositions comprising a predominant mixture or organic volatalisable materials which may or may not be chemically changed on irradiation.

A preferred embodiment of the latter aspect of the invention is a predominant mixture or organic volatalisable materials which is a mixture of surfactants more preferably surfactants as used for personal cleansing, e g soap bars and the like.

Detailed description of the invention.

The invention allows either complete or partial surface modification of a detergents solids with very high resolution, speed and flexibility allowing extremely fast and selective variation in application A particular advantage of the method is that it requires no consumables in use and is therefore environmentally more acceptable.

The invention provides the use of high intensity coherent electromagnetic radiation source in the ultra-violet to infra red wavelength range for the surface modification of solid or substantially solid detergents products The detergents products are preferably in the form of a detergent powder, granulate, extrudate or tablets, most preferably where the detergent article is a detergent or sanitising tablet.

In particular the use of a carbon dioxide laser, preferably with suitable optics to manipulate the beam, typically linked to computer control are within the scope of the invention.

The surface modification may arise from many mechanisms for example surface ablation, deformation, dehydration, distortion, pyrolysis or sublimation Without wishing to be bound by theory it is hypothesised that the high intensity and short duration of the laser beam gives rise to volatilisation, particularly sublimation of organic materials thus preferably avoiding pyrolysis and therefore avoiding burn marks As part of the invention laser intensity and scanning rate and wavelength are chosen to obtain what ever effect is desired.

The invention requires the surface to be irradiated to be predominant mixture or organic volatalisable materials and inorganic, non-metallic substantially non-volatile materials Suitable materials are listed below as detergent components and examples are given of two particularly suitable compositions The person skilled in the art will recognise that the principle extends to a wide range of organic materials, for example pharmaceuticals and that the inorganic materials extend to a wide range of metal salts Though the predominance of alkali and alkaline earth metal salts (herein to include alumino silicates and the like with these counter ions) is a preferred embodiment of the invention Not wishing to be bound by theory it is thought that their low adsorbtion of light and high volatalisation temperatures are beneficial in differentiating them from the organic components response to irradiation However, another preferred embodiment is the use of heat sensitive salts, particularly carbonates and bicarbonates which can loose carbon dioxide and leave a surface more clearly differentiated from any untreated area.

4 The invention is characterised in that there are preferred ratios of inorganic to organic materials and where there are mixtures of liquids and solids preferred ratios of these also Whilst ratios of inorganic to organic materials in the range 1000:1 to 1:1000 typical ratios are in the order 50:1 to 1:2 and more preferably in the range 30:1 to 1:1 A further aspect of the invention is the use of the technique with soap bars and the like wherein typical ratios are much lower and in which very little, even trace amounts of inorganic material are present.

The practical application of the invention arises from three principle uses; surface marking; surface depletion; surface removal of dyes, surface decomposition or combinations thereof.

Surface marking Since visual marking requires only surface modification above the wavelength of light, surfaces treated with a high intensity laser may exhibit visible change.

However, detergents articles typically present a rough surface and it has been found that a combination of the organic volatalisable material and inorganic non-volatile material can give a particularly visually perceivable change of the products surface.

In particular by the differential effects the laser light has when impacting a surface of mixed composition It is an object of the invention to provide to provide a means of marking products, e g with date codes, logo's etc.

It is becoming increasingly popular to pack detergents products in clear wrapping materials to enable the consumer to observe the product clearly on purchase for example This gives rise to the need for colour stability against light, for example UV light It is a particularly advantageous benefit of this method of marking that light fading does not occur.

Surface removal of dyes The inherent laser marking of an uncoloured detergents surface can be limited and hence a further object of the invention is the provision of a coloured surface By for example, spraying colour on to the surface, which colour (e g a dye) is selectively removed or decomposed by the application of the laser light It is an object of the invention to provide to provide a means of marking products by the selective removal of dye from a dyed surface or the surface layer of a dyed body, particularly a detergents body Examples of suitable dyes are listed below.

It is a particularly preferred aspect of the invention that the dye chosen should have a wavelength of adsorbtion within +M-1 O Onm preferably +/-5 Onm of the wavelength of the laser light used.

Surface depletion This is a combination of the above properties whereby liquids materials are volatalised from the surface This is beneficial since liquids typically leach ('bleed') by capillary action from predominantly solid detergents containing them on to the packaging materials (particularly card and paper) causing unsightly 'bleeding' marks.

It is an object of the invention to provide comprehensive surface depletion of such materials with the object of reducing such 'bleeding', It is a particularly preferred aspect of the invention that the wavelength of the laser light be chosen to correspond to the light absorbtion maxima (Lambda max) of one of the components of the surface to be modified, in particular the adsorbtion maxima of the volatile component or components, particularly liquid nonionic surfactants as herein described.

Surface decomposition Detergents products contain components which are desirable in the wash but less desirable in undiluted contact with the skin or delicate articles An aspect of the invention is therefore the surface decomposition of bleach activator or enzyme The former can give localised dye damage of textiles if a washing tablet is placed on damp cloth e g at the beginning of a wash The latter can give skin irritation to sensitive individuals who may handle the tablet before dissolution.

Laser type A Carbon dioxide laser of several watts intensity is typically chosen The active medium being typically a mixture of Carbon dioxide, nitrogen and helium, for example in the ration 0 8 to 1 to 1 7.

Helium-neon lasers are also within the scope of the invention but since these are usually of low wattage (e g < 50 m W) they are usually not economic.

Solid state lasers are also within the scope of the invention, for example, Ruby, Nd:YAG, Nd:Glass lasers These lasers are particularly preferred due to their lower complexity and potential for high power output YAG is a complex crystal of Yttrium, Aluminium, a Garnet or formula Y 3 A 15012.

It is envisaged that other lasers will become available and as such will be chosen by the person skilled in the art to best perform the functions described It is within the scope of the invention to use two laser light sources For example, one to selectively remove dye (e g red light), the other for decomposing material (e g short wavelength UV).

Commercial equipment Suitable equipment for application of the current invention is the Laser Pro DM Tm as sold by Video Jet Systems International a division of GEC.

Laser intensity Intensity required is largely dependent upon the volatility / decomposition and light adsorbtion characteristics of the materials in question However, light intensity in the range from 1 watt to 100 k W watts per square centimetre, preferably from 10 watts to k W watts per square centimetre most preferably from 100 to 1000 watts for square centimetre is within the scope of the invention Typically this will be achieved by scanning a laser beam over the surface to be treated and hence the intensity of the beam need only be a fraction of this wattage Significantly this wattage input should 6 be achieved, for any given area, in a short time period as opposed to irradiation at a low level for a long time period It is therefore implicit in the invention that the laser light should irradiate any given portion of the surface to be treated for not more than 1 second, more preferably not more than 0 5 seconds and most preferably for not more than 0 1 seconds.

Detergent products according to the invention comprise a detersive surfactant and optional additional detergent components as described below:

Detersive surfactant Any surfactant materials capable of reducing the air water surface tension of pure water when incorporated at a level of 1 % is within the scope of the invention.

The detersive surfactant which goes to make a detergent may 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 1 to 25 %, preferably from 5 to 20 % by weight in a detergent formulation.

If 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 1 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).

R 1 R 3-N±CH 2-COO (I) R 2 R' R 3 ONHCH 2 CH 2 CH 2 NCH 2 COO (II) R 2 In the above formula, R 1 and R 2 may be the same or different C 14 alkyl groups whereas R 3 is an alkyl group having 8-22 carbon atoms, more preferably 12 to 18 carbon atoms e g mixed C 10 to C 14.

The preferred betaine for use is cocoamidopropyl betaine.

7 An alternative amphoteric surface active agent for use in the formulation of the invention is a glycinate of the formula R 3 NHCH 2 CO 2 H where R 3 is as defined above.

Other suitable materials are as given in chapter 1 of "Amphoteric Surfactants", e g.

Lomax Ed, Marcel Decker, New York 1996.

It is highly 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 % by 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 (C 1-4) alkyl groups (preferably methyl groups) and a long chain (C 820) alkyl group, e g.

coco trimethyl ammonium chloride Further examples include alkyl pyridinium 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.

If 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 010 to 020, more preferably with, 012 to 018 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 liquid 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 010 to 020, more preferably with, 012 to 018 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 A 3 and SYNPERONIC A 7 Mixtures of the A 7 and A 3 active agents may also be used Also suitable are LUTENSOL A 03 and LUTENSOL A 07 (ex BASF).

8 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 (C 8-22)polyglycosides The preferred glycoside for use in the present invention is a glucoside (i e based on glucose), functionalised with a primary alcohol (e.g C 12-C 14) 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 30 % by weight, more preferably at least 40 % by weight of solid non-ionic surface active agent.

A suitable polyglycosides are available under the name Glucopon (Henkel).

Preferably used as Glucopon G 50 granules ( 50 % APG Glucopon, 50 % sulphate).

The surfactant can be present at up to 25 %, more preferably between 1 % and 20 %.

For textile washing compositions the most preferable range is between 10 and 20 % and for hard surface cleaning between 1 and 5 % and for fabric refresher and air freshener products less than 1 % 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, derivitised 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.

Cyclodextrin 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 % 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 triphosphates 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 A 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.

9 Of the material printed, sprayed or otherwise deposited on the detergent surface a level of polymer from O to 70 % may be used, preferably a polymer level of 0 to 50 %, more preferably from 1 to 20 %, most preferably from 5 to 15 %.

Of any material in the bulk of the composition 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 within the scope of the invention.

Other suitable polymers include condensation polymers e g Poly; esters, and urethanes, gelatine, 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 (e g.

Croduret 50 ex Croda), acrylic acid polymers (e g ex National Starch) Acrylate maleate polymers (e g Sokolan CP-5 and CP-10 ex BASF) and poly ethylene glycols (e g ex Hoechst), poly vinyl pyrrolidone (e g K 50 ex ISP), Carbopol (ex 3 V).

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 substantially water insoluble polymers may be added to perform a variety of functions for example soil release agents and tablet excipients E g.

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 potential 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 e g 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-0 525 239 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 compound 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 937 772 (Procter).

Effervescent systems An effervescent system may be employed Suitable agents include a mixture of an acid and an alkali metal carbonate or bicarbonate, for example citric acid and sodium carbonate Sodium percarbonate peroxohydrate (e g ex Eka chemicals) is also considered.

Clays A 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 formulations Such clays are generally of the "lamellar type" and are such that the layers "separate" to become deposited on the garments being washed The clay 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 SodiumSaponite, 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 11 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, 1987, said patent being incorporated herein by reference Examples of nonionic fabric softeners are the sorbitan esters, C 12 to C 26 fatty alcohols, and fatty amines 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, amide 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 0.1 to 3 % This level is particularly suitable for Savinase 6 O T, Termamyl 60 T, Celluzyme 0 7 T 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 5 % by weight as a processing aid.

Particularly preferred are those with C 8 to C 22 alkyl chains, more preferably C 12 to C 12 alkyl and with an iodine value less than 5 more preferably less than 1 Mono, di and trifunctional acids are not without the scope of the invention Particularly suitable are the Prifac (TM) and Pristerine (TM) materials supplied by 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 zeolite), p H 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 perfume will typically be formulated in a product using the invention The perfume ingredients and compositions preferred are the conventional ones known in the art.

Selection of any perfume component, or amount of perfume, is based on aesthetic 12 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 % of d-limonene Examples of moderately volatile perfume ingredients are: amyl cinnamic aldehyde, iso-amyl salicylate, beta-caryophyllene, cedrene, cinnamic alcohol, coumarin, 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 ( 1,3,4, 6,7,8- hexahydro 4,6,6,7,8,8 hexamethyl-cyclo-penta-gama-2-benzopyran), hexyl cinnamic aldehyde, lyral ( 4 ( 4 hydroxy-4-methyl pentyl) 3 cyclohexene 10 - carboxaldehyde), methyl cedrylone, methyl dihydro jasmonate, methyl-beta-naphthyl ketone, musk indanone, musk ketone, musk tibetene, and phenyl ethyl phenyl acetate Such components are particularly preferred constituents of any perfume composition used in the invention.

Bactericide A 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 1 to 0 005 % most preferably from 0 1 to 0 01 % Biocides as listed in annex 1 of the Biocidal Products Directive of the EC are considered 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, 13 preferably from 3 to 0 0001 %, more preferably from 1 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 theory 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 COURLOSE and NYMCEL A particularly suitable disintegrant for use with the invention is available under the trade mark NILYN (ex FMC), grade LX 16 which is an internally cross-linked carboxymethyl cellulose.

Further examples of disintegrants which may be used include various starches such as potato, rice, corn 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 EXPLOTAB.

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) disulphonate and Tinopal DMS-X ( 4,4 ' bis ( 2-morpholino-4-anilino-5- 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 14 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.

Electricaliy-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 jet printing, the ink is driven from the nozzle toward the print medium by the formation of an expanding vapour 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").

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

Classes and principles of preferred colourant systems In commercially-available thermal ink-jet colour printers, such as the Desk Jet TM printer available from Hewlett-Packard Company, a colour spectrum is achieved by combining cyan, magenta, and yellow inks in various proportions A four- pen set including the three primary colour inks and a black ink is typically employed in such printers to achieve the necessary colour 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 purposes 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 water fastness and light fastness Specific colourant materials Specific dyes within the scope of the invention and preferably used therein.

A water soluble dye system characterised in that the dye system comprises a dye selected from the group consisting of:

1 Quinoline Yellow 70 with colour index no 47005; 2 Tartrazine XX 90 with colour index no 19140; 3 Orange RGL 90 with colour index no 15985; 4 Ponceau 4 RC 82 with colour index no 16255; Blue AE 85 with colour index no 42090; 6 Patent Blue V 85 N 50 with colour index no 42051; and It will be appreciated that the foregoing is a limited list of preferable dyes and that other similar materials familiar to the colourist skilled in the art may be used.

Polymeric colourants Such materials are particularly preferred as, not wishing to be bound by theory, they exhibit lower smudging on storage which is understood to be exacerbated by surfactant and so the beneficial use is specific to or exemplified by detergent compositions.

Polymeric Colourants Supplier Liquitint (tm) blue 710230 Milliken Liquitint (tm) yellow EC 710406 Milliken Liquitint (tm) blue 710407 Milliken Liquitint (tm) violet PG 710233 Milliken Liquitint (tm) red RL 710208 Milliken Use of the above colourants and mixtures thereof is within the scope of the invention.

Specific pigments Pigmentatious colourants are a particularly preferred method of colourantion and, not wishing to be bound by theory, are particularly 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 3 G Ciba-Geigy Yellow 93 Chromophtal (tm) Yellow GR Ciba-Geigy Yellow 95 Chromophtal (tm) Yellow 8 G Ciba-Geigy Yellow 128 Dalamar (tm) Yellow YT-858-D Heubach Yellow 74 16 Hansa Yellow RA Hoechst Yellow 73 Hansa Brilliant Yellow 5 GX-02 Hoechst Yellow 74 Hansa Brilliant Yellow 10 GX Hoechst Yellow 98 Hansa Yellow X Hoechst Yellow 75 Heliogen (tm) Blue K 7090 BASF Blue 15:3 Heliogen (tm) Blue L 7101 F 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 6901 F BASF Blue 15:2 Heucophthal (tm) Blue G Heubach Blue 15:3 Hostaperm (tm) Scarlet GO Hoechst Red 168 Hostaperm (tm) Yellow H 4 G Hoechst Yellow 151 Hostaperm (tm) Yellow H 3 G 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 4 BL Ciba-Geigy Red 57:1 Irgazin (tm) Yellow 5 GT Ciba-Geigy Yellow 129 L 74-1357 Yellow Sun Chem.

L 75-1331 Yellow Sun Chem.

L 75-2377 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 207 Monastral (tm) Red B Ciba-Geigy Violet 18 Novoperm (tm) Yellow FGL Hoechst Yellow 97 Novoperm (tm) Yellow HR Hoechst Yellow 83 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 G 3 R-01 Hoechst Yellow 114 Permanent Rubine F 6 B Hoechst Red 184 Permanent Yellow DHG Hoechst Yellow 12 Quindo (tm) Red R 6713 Mobay Quindo (tm) Red R 6700 Mobay Quindo (tm) Magenta Mobay Red 122 Raven (tm) 1170 Col Chem Black 7 Special Black 4 A Degussa Black 7 Sterling (tm) NSX 76 Cabot Black 7 Sterling (tm) NS Black Cabot Black 7 Tipure (tm) R-101 Du Pont 17 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 11741) Graphite Hansa (tm) Yellow (Pigment Yellow 98) Heucophthal (tm) Blue BT-585-P Indo (tm) Brilliant Scarlet (Pigment Red 123, C I No 71145) Magenta RV-6831 press cake (Mobay Chemical, Haledon,N J) Permanent Rubine F 6 B 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 3) Watchung (tm) Red B (C I Pigment Red 48) Black pigments, such as, Carbon black generally are not available in the form of aqueous press cakes, but such a form is not excluded from the scope of the invention.

The above colourants and mixtures thereof are within the scope of use in the invention.

Metallic ink jet inks Fine 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 ink jet 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 the scope of the invention.

Additional colourant components and adjuncts To form a dye, ink or other formulated colourant composition using the aforementioned basic colour stuffs 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 A segment of said block copolymer is a homo polymer 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 18 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 their corresponding esters of are also considered suitable.

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

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

19 U.S 5,180,425, describes ink jet ink compositions which include an aqueous carrier medium, a pigment dispersion, and a polyol/alkylene oxide co- solvent.

These inks are taught to provide long functional life to ink jet printers and to resist film formation Liponic EG-1 is one of the preferred co-solvents disclosed Other optional solvents which may be used in the described invention include polyethylene glycol U S 5,302,197,, describes aqueous ink jet ink compositions which comprise a pigment dispersion, an aqueous carrier medium, and a co-solvent 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 603,469, describes ink jet inks comprising an aqueous carrier medium, specifically-defined alkyl polyol ether co-solvents, and a pigment dispersion (pigment particles stabilised by a dispersant) These inks are taught to provide a good balance of viscosity, surface tension, 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 co-solvent mixture containing C 2 to C 8 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 optimised properties Specifically, these compositions provide excellent properties in terms of stability, optical density (even when low levels of pigment are utilised), viscosity, printing characteristics (water-fastness, minimised feathering, minimised running of ink on the printed page), and printer maintenance problems (i e, minimised clogging of the printer jets during gaps in printer usage).

Detergent tablets Detergent tablets are a particularly preferred 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, brick, briquette, cake or tablet.

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

A pressure of 100 k Pa to 1000 M Pa will generally be suitable for forming the tablet.

More preferably, a pressure of 200 k Pa to 100 M Pa is used and even more preferably one of 250 k Pa to 10 M Pa, most preferably from 300 k Pa to 5000 k Pa.

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 by 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 PH 400 series ex Korsch of Berlin, the 3090 series ex Wilhem Fette of Hamburg or model MOD BR 680 ex J.

Bonal S A, Barcelona.

Tableting presses generally work by 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 by 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 if 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 by means of scrapers The press should allow the tablet thickness to be adjustable For a given die/punch size,Ahis 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 M Pa, which for a 20 gram tablet would translate to an applied force per tablet of about 0 18 to 45 k N 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 by use of equipment to measure its breaking strength under compression, such as the Holland CT 5 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 1 cm square which corresponds to about 500-5000 k Pa Such a measure can conveniently be taken using a Holland CT 5 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 in juxtaposed 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 20 g to 60 g 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 is considered appropriate and even advantageous to combine such coating with a homogeneously coloured tablet or portion thereof particularly when 21 the tablet is therefore seen to change appearance when the external layer is removed.

Capsules are also within the scope of the invention.

Examples

The invention is illustrated using the following non limiting examples.

Relative persistence under UV light A tabletted detergent was prepared as follows; Composition 1 (Automatic dish washing composition) RAW MATERIAL % by weight Sodium Triphosphate to 100 % Sodium Disilicate Heavy Granular 25 0 Granular Sodium Carbonate 8 40 Sodium Perborate monohydrate 12 5 Polyvinyl pyrrolidone MW 25,000 2 5 Dequest 2016 D 0 40 Benzotriazole 0 20 Polyethylene Glycol 0 20 TAED 3 00 Synperonic LF/RA 260 ex ICI 3 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 36 mm long by 26 mm wide and weighing 20 grams at the pressure indicated of 8 tons.

Tablets are annotated with a 5 mm wide line; (a) by ink jet printing (see application GB 0006768 6 for detailed methodology) using Ink 5; (b) by laser using a Laser Pro DM TM as sold by Video Jet Systems International a division of GEC.

Ink 5 Component Level Blue AE 85 with colour index no 42090 18 % Methacrylic acid, Methyl methacrylate co Polymer 10 % Diethylene glycol Deionized water 41 % to 100 % In both cases a visually distinct line is observable.

23 The tablets where then subjected to accelerated UV stability testingusing a 1 90 nm tubular 30 cm UV lamp of 15 watts at a distance of 5 cm for 1 hour.

Results: Sample a) had faded sufficiently that the annotated stripe was barely visible and the what was visible no longer blue Sample b) had shows no noticeable change in appearance This demonstrates the improved light stability of laser marking of detergents solids.

Surface depletion of dyes A tablet (a) as above was treated as tablet (b) above, but with the stripe offset to one side by 2 mm, this is tablet (c).

Result, the laser treated dyed portion was effectively reduced to the background tablet colour The edge of the treated area (edge t) was subjectively sharper than the edge created from Ink jet printing only (edge i) It appeared that the Ink jet had diffused edges due to some bleeding of dye in to the porous surface, the removal process appeared to remove what was radiated on irrespective of surface roughness, creating a sharper edge The edge created-only by the laser (edge I) is equally sharp.

Anti-bleeding test A tablet of the following composition was prepared; Composition 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 % 7 EO ALKYL ETHOXYLATE 10 % SODIUM ALKYL BENZENE SULPHONATE 10 % % SODIUM SILICATE SOLUTION (BINDER) 12 % PERFUME 0 5 % 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 tabletted at the specified pressure of 2 tons to form a tablet of 44 mm diameter and g weight.

A tablet was treated as in method (a) above and placed on a piece of packing board of 900 um 650 gram Colthrope Coated Greyback packing card (ex Colthrope UK) The sample was left at 37 'C for 24 hours with a weight of 100 g holding the materials in contact.

Result, the laser treated stripe showed less/no wicking of surfactant on to the paper to give staining This shows the anti-bleed benefit of laser surface treatment.

Anti diffusion on storage compared to inks Tablets prepared as (c) using tablet composition above are stored at 37 C and 50 % relative humidity for four weeks.

Result Edge i (definitions above) was diffuse and diffused up to 1 5 mm approximately away from the original position Edge I was less distinct than before but had not diffused Edge t was diffuse and diffused up to 1 25 mm approximately away from the original position This shows that edges on dyed surface created by laser depletion of dye are less prone to future diffusion and can remain clearer longer.

Claims (1)

1. Claims

   1) The use of high intensity coherent electromagnetic radiation source or sources in the ultra-violet to infra red wavelength range for the surface modification of solid or substantially solid product compositions comprising a predominant mixture or organic volatalisable materials and inorganic, non-

   metallic substantially non-volatile materials 2) A method as in claim 1 where the 'high intensity coherent electromagnetic radiation source' is a carbon dioxide, Nd:YAG, Ruby or Helium Neon laser.

   3) A method as in claim 2 where the 'high intensity coherent electromagnetic radiation source' is a carbon dioxide laser.

   4) A method as in claim 1 where the 'solid or substantially solid product compositions comprising a predominant mixture or organic volatalisable materials and inorganic, non-metallic substantially non-volatile materials which may or may not be chemically changed on irradiation' is a detergent article.

   5) A method as in claim 4 wherein the detergent article is a detergent powder, granulate, extrudate or tablet.

   6) A method of annotating detergents articles using laser light so as to produce a surface modification which conveys information.

   7) A method as described in claim 6 whereby the light source of the invention is controlled by a computer which modifies an acousto optical crystal or electro optical crystal or similar to manipulate the light so as to produce a surface modification which conveys information.

   8) A method of surface treatment using laser light so as to remove colouration from an already coloured detergents object so as to produce a visible surface modification.

   9) A method of surface treatment as described in claim 8 wherein the object is coloured at least in part by a surface layer of colouration that is at least partially removed by the laser light.

   1 O)According to a further aspect of the invention there is provided an the use of high intensity coherent electromagnetic radiation source in the ultra- violet to infra red wavelength range for the surface modification of solid or substantially solid product compositions comprising a predominant mixture of predominantly detergent surfactants.