WO2008110748A2

WO2008110748A2 - Phthalocyanines and their use in ink-jet printing

Info

Publication number: WO2008110748A2
Application number: PCT/GB2008/000748
Authority: WO
Inventors: Neil James Thompson; Prakash Patel
Original assignee: Fujifilm Imaging Colorants Ltd
Current assignee: Fujifilm Imaging Colorants Ltd
Priority date: 2007-03-15
Filing date: 2008-03-05
Publication date: 2008-09-18
Anticipated expiration: 2009-09-15
Also published as: GB0914164D0; GB2459797A; WO2008110748A3; GB0704967D0

Abstract

A compound of Formula (1 ) and salts thereof: MPc - (R1-NR2-R3)n Formula (1 ) wherein: M is Cu or Ni; Pc represents a | phthalocyanine nucleus of formula; R1 is optionally substituted C1-4alkylene; R2 is H or optionally substituted C1-4alkyl; R3 is optionally substituted alkyl, optionally substituted aryl, optionally substituted acyl or optionally substituted heterocyclyl; or R2 and R3 are joined together to form with the nitrogen a heterocyclic ring which may contain other heteroatoms; n is 1 to 8: and provided that at least one of R1, R2 and R3 carries at least one acidic water solubilising substituent selected from the group consisting Of -SO3H, -CO2H and -PO3H2. Also compositions, inks, printing processes, printed materials and ink-jet cartridges.

Description

PHTHALOCYANINES AND THEIR USE IN INK-JET PRINTING

This invention relates to compounds, compositions and inks, to printing processes, to printed substrates and to ink-jet printer cartridges.

Ink-jet printing is a non-impact printing technique in which droplets of ink are ejected through a fine nozzle onto a substrate without bringing the nozzle into contact with the substrate. The set of inks used in this technique typically comprise yellow, magenta, cyan and black inks.

With the advent of high-resolution digital cameras and ink-jet printers it is becoming increasingly common for consumers to print off photographs using an ink-jet printer. This avoids the expense and inconvenience of conventional silver halide photography and provides a print quickly and conveniently.

While ink-jet printers have many advantages over other forms of printing and image development there are still technical challenges to be addressed. For example, there are the contradictory requirements of providing ink colorants that are soluble in the ink medium and yet display excellent wet-fastness (i.e. prints do not run or smudge when printed). The inks also need to dry quickly to avoid sheets sticking together after they have been printed, but they should not form a crust over the tiny nozzle used in the printer. Storage stability is also important to avoid particle formation that could block the tiny nozzles used in the printer especially since consumers can keep an ink-jet ink cartridge for several months. Furthermore, and especially important with photographic quality reproductions, the resultant images should not fade rapidly on exposure to light or common oxidising gases such as ozone. It is also important that the shade and chroma of the colorant are exactly right so that an image may be optimally reproduced. Most cyan colorants used in ink-jet printing are based on phthalocyanines and problems of fading and shade change on exposure to light and contact with ozone are particularly acute with dyes of this class.

Thus developing new colorants for ink-jet printing presents a unique challenge in balancing all these conflicting and demanding properties. The present invention provides a compound of Formula (1 ) and salts thereof:

MPc — (R¹-NR²-R³)_n

Formula (1 ) wherein:

M is Cu or Ni;

Pc represents a phthalocyanine nucleus of formula;

R¹ is optionally substituted C-^alkylene; R² is H or optionally substituted

R³ is optionally substituted alkyl, optionally substituted aryl, optionally substituted acyl or optionally substituted heterocyclyl; or R² and R³ are joined together to form with the nitrogen a heterocyclic ring which may contain other heteroatoms; n is 1 to 8: and provided that at least one of R¹, R² and R³ carries at least one acidic water solubilising substituent selected from the group consisting of -SOaH, -CO₂H and -PO₃H₂. M is preferably Cu.

Preferably R¹ is unsubstituted more preferably R¹ is methylene.

Preferably R² is H or unsubstitute

ore preferably R² is H or methyl, especially H.

Preferably R³ is optionally substituted C-|.i₂alkyl (especially optionally substituted C-ι_-8alkyl), optionally substituted aryl (especially optionally substituted phenyl) or optionally substituted heteroaryl (especially optionally substituted piperidine, optionally substituted morpholine, optionally substituted pyrrolidine or optionally substituted triazine).

More preferably R³ is optionally substituted Ci_-8alkyl especially: optionally substituted C_halky! substituted with at least one acidic water solubilising substituent selected from the group consisting of -SO₃H, -CO₂H and -POaH₂; optionally substituted Ci_-8alkyl substituted with an optionally substituted heteroaryl; or optionally substituted C_halky! substituted with optionally substituted phenyl.

It is particularly preferred that R³ is carrying 1 or 2, particularly 2, acidic water solubilising substituents selected from the group consisting of -SO₃H,

-CO₂H and -PO₃H₂; C_1-4alkyl carrying an optionally substituted heteroaryl (where preferably the heteroaryl group or substituent thereof carries at least one acidic water solubilising substituent selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂); or C-i^alkyl carrying an optionally substituted phenyl group (where preferably the phenyl group or substituent thereof carries at least one acidic water solubilising substituent selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂).

Preferably the optionally substituted heteroaryl substituent on the optionally substituted C_1-4alkyl of R³ comprises a nitrogen heteroaryl and more preferably comprises a triazinyl radical.

It is especially preferred that R³ is optionally substituted

carrying an optionally substituted triazinyl which carries either directly or on a substituent at least one acidic water solubilising substituent selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂.

It is especially preferred that the optionally substituted triazinyl substituent on the optionally substituted C^alkyl of R³ is a group of Formula (2)

Formula (2) wherein:

X is selected from the group consisting of -OR⁴, -SR⁴, -NR⁴R⁵; Y is selected from the group consisting of -OR⁶, -SR⁶, -NR⁶R⁷;

R⁴, R⁵, R⁶ and R⁷ are independently H, optionally substituted alkyl, optionally substituted aryl or optionally substituted heterocyclyl provided that at least one of the groups represented by R⁴, R⁵, R⁶ and R⁷ carries at least one acidic water solubilising substituent selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂.

Preferred groups represented by X and Y include -OH, -NHCH₃, -N(CH₃)₂, -NHC₂H₄SO₃H₂, -N(CH₃)C₂H₄SO₃H₂, -NC₃H₆SO₃H, -NHdisulfophenyl,

-NHsulfophenyl, -NHcarboxyphenyl or -NHdicarboxyphenyl, -NHsulfonaphthyl, -NHdisulfonaphthyl, -NHtrisulfonaphthyl, -NHcarboxyonaphthyl, NHdicarboxyonaphthyl, NHtricarboxyonaphthyl-NHsulfoheterocyclyl,

NHdisulfoheterocyclyl or -NHtrisulfoheterocyclyl.

It is especially preferred that the triazinyl substituent on the optionally substituted C_1-4alkyl of R³ is a group of Formula (3)

Formula (3) wherein:

R⁸ is H or optionally substituted C^alkyl; R⁹ is H or optionally substituted

R¹⁰ is H or optionally substituted Ci^alkyl;

R¹¹ is optionally substituted alkyl, optionally substituted aryl or optionally substituted heterocyclyl carrying at least one acidic water solubilising substituent selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂.

Preferably R⁸ is H or unsubstituted

more preferably R¹⁰ is H or methyl especially H.

Preferably R⁹ is H (especially methyl), unsubstituted C_1-4alkyl or C^alkyl carrying at least one acidic water solubilising substituent selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂.

Preferably R¹⁰ is H or unsubstituted Ci^alkyl, more preferably R¹² is H or methyl especially H. .

In a preferred embodiment R⁸, R⁹ and R¹⁰ are all independently either H or methyl, more preferably R⁸, R⁹ and R¹⁰ are all H. Preferably R¹¹ is or

carrying at least one acidic water solubilising substituent selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂ or optionally substituted aryl carrying at least one acidic water solubilising substituent selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂. More preferably R¹¹ is C_2-4alkyl carrying at least one acidic water solubilising substituent selected from the group consisting of -SO₃H and -CO₂H or an aryl group (particularly a phenyl group) carrying 1 to 3, especially 2, -SO₃H or -CO₂H substituents.

Preferably n is 1 to 8, more preferably n is 1 to 4, especially 2 to 4, more especially 3 to 4 and particularly 4. A particularly preferred compound of Formula (1 ) is of Formula (4) and salts thereof

Formula (4) wherein:

Pc represents a phthalocyanine nucleus;

R¹³, R¹⁴ and R¹⁶ are each independently H or methyl; R¹⁵ and R¹⁷ are independently

carrying 1 to 3 acidic water solubilising substituents selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂ and optionally other substituents or aryl carrying 1 to 3 acidic water solubilising substituents selected from the group consisting of -SO₃H, -CO2H and -PO₃H₂ and optionally other substituents; and n is 1 to 4.

R¹² is preferably -CH₂-.

In a preferred embodiment R¹³, R¹⁴, R¹⁵ and R¹⁶ are all H and R¹⁷ is aryl carrying 1 to 3 acidic water solubilising substituents selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂ (more preferably -SO₃H and -CO₂H) and optionally other substituents.

In a second preferred embodiment R¹³, R¹⁴ and R¹⁶ are all H and R¹⁵ and R¹⁷ are both Ci^alkyl carrying 1 to 3 acidic water solubilising substituents selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂ (more preferably -SO₃H and -CO₂H) and optionally other substituents.

Preferred optional substituents which may be present on any one of R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹⁵ and R¹⁷ are independently selected from: optionally substituted alkoxy (preferably

optionally substituted aryl (preferably phenyl), optionally substituted aryloxy (preferably phenoxy), optionally substituted heterocyclyl, polyalkylene oxide (preferably polyethylene oxide or polypropylene oxide), phosphato, nitro, cyano, halo, ureido, hydroxy, ester, -NR^aR^b, -COR^a, -CONR^aR^b, -NHCOR³, carboxyester, sulfone, and -SO₂NR^aR^b, wherein R^a and R^b are each independently H or optionally substituted alkyl (especially C_1-4-alkyl). When R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹⁵ and R¹⁷ comprise a cyclic group they may also carry an optionally substituted alkyl (especially d-₄-alkyl) substituent. Optional substituents for any of the substituents described for R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹⁵ and R¹⁷ may be selected from the same list of substituents.

In a particularly preferred embodiment the substituents represented by n are bound only to the β-position of the phthalocyanine ring.

The compounds of Formula (1 ) are also preferably free from fibre reactive groups. The term fibre reactive group is well known in the art and is described for example in EP 0356014 A1. Fibre reactive groups are capable, under suitable conditions, of reacting with the hydroxyl groups present in cellulosic fibres or with the amino groups present in natural fibres to form a covalent linkage between the fibre and the dye. As examples of fibre reactive groups excluded from the compounds of Formula (1 ) there may be mentioned aliphatic sulfonyl groups which contain a sulfate ester group in beta-position to the sulfur atom, e.g. beta- sulfato-ethylsulfonyl groups, alpha, beta-unsaturated acyl radicals of aliphatic carboxylic acids, for example acrylic acid, alpha-chloro-acrylic acid, alpha- bromoacrylic acid, propiolic acid, maleic acid and mono- and dichloro maleic; also the acyl radicals of acids which contain a substituent which reacts with cellulose in the presence of an alkali, e.g. the radical of a halogenated aliphatic acid such as chloroacetic acid, beta-chloro and beta-bromopropionic acids and alpha, beta- dichloro- and dibromopropionic acids or radicals of vinylsulfonyl- or beta- chloroethylsulfonyl- or beta-sulfatoethyl-sulfonyl-endo- methylene cyclohexane carboxylic acids. Other examples of cellulose reactive groups are tetrafluorocyclobutyl carbonyl, trifluoro-cyclobutenyl carbonyl, tetrafluorocyclobutylethenyl carbonyl, trifluoro-cyclobutenylethenyl carbonyl; activated halogenated 1 ,3-dicyanobenzene radicals; and heterocyclic radicals which contain 1 , 2 or 3 nitrogen atoms in the heterocyclic ring and at least one cellulose reactive substituent on a carbon atom of the ring, for example a triazinyl halide. Acid or basic groups on the compounds of Formula (1 ), particularly acid groups, are preferably in the form of a salt. Thus, all Formulae shown herein include the compounds in salt form.

Preferred salts are alkali metal salts, especially lithium, sodium and potassium, ammonium and substituted ammonium salts (including quaternary amines such as ((CH₃)₄N⁺) and mixtures thereof. Especially preferred are salts with sodium, lithium, ammonia and volatile amines, more especially sodium salts.

Compounds of Formula (1 ) may be converted into a salt using known techniques.

The compounds of Formula (1 ) may exist in tautomeric forms other than those shown in this specification. These tautomers are included within the scope of the present invention.

The mixtures of compounds of Formula (1 ) may be prepared by reacting a amino methyl copper phthalocyanine (prepared as in Example 30 of US 2,761 ,868) with a compound of formula R³-X, wherein R³ is as defined above and X is an active leaving group. These compounds are commercially available (e.g. cyanuric chloride) or may be readily made using processes which would be well known to one skilled in the art. The compounds of Formula (1 ) have attractive, strong cyan shades and are valuable colorants for use in the preparation of ink-jet printing inks. They benefit from a good balance of solubility, storage stability and fastness to water, ozone and light. In particular they display excellent wet fastness and ozone fastness.

According to a second aspect of the present invention there is provided a composition comprising a compound of Formula (1 ) as described in the first aspect of the invention and a liquid medium.

Preferred compositions according to the second aspect of the invention comprise:

(a) from 0.01 to 30 parts of a compound of Formula (1 ) according to the first aspect of the invention; and (b) from 70 to 99.99 parts of a liquid medium; wherein all parts are by weight.

Preferably the number of parts of (a)+(b)=100.

The number of parts of component (a) is preferably from 0.1 to 20, more preferably from 0.5 to 15, and especially from 1 to 5 parts. The number of parts of component (b) is preferably from 80 to 99.9, more preferably from 85 to 99.5 and especially from 95 to 99 parts.

Preferably component (a) is completely dissolved in component (b).

Preferably component (a) has a solubility in component (b) at 20°C of at least 10%.

This allows the preparation of liquid dye concentrates that may be used to prepare more dilute inks and reduces the chance of the dye precipitating if evaporation of the liquid medium occurs during storage.

The inks may be incorporated in an ink-jet printer as a high concentration cyan ink, a low concentration cyan ink or both a high concentration and a low concentration ink. In the latter case this can lead to improvements in the resolution and quality of printed images. Thus the present invention also provides a composition (preferably an ink) where component (a) is present in an amount of 2.5 to 7 parts, more preferably 2.5 to 5 parts (a high concentration ink) or component (a) is present in an amount of 0.5 to 2.4 parts, more preferably 0.5 to 1.5 parts (a low concentration ink). Preferred liquid media include water, a mixture of water and organic solvent and organic solvent free from water. Preferably the liquid medium comprises a mixture of water and organic solvent or organic solvent free from water.

When the liquid medium (b) comprises a mixture of water and organic solvent, the weight ratio of water to organic solvent is preferably from 99:1 to 1 :99, more preferably from 99:1 to 50:50 and especially from 95:5 to 80:20.

It is preferred that the organic solvent present in the mixture of water and organic solvent is a water-miscible organic solvent or a mixture of such solvents. Preferred water-miscible organic solvents include d-β-alkanols, preferably methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, n- pentanol, cyclopentanol and cyclohexanol; linear amides, preferably dimethylformamide or dimethylacetamide; ketones and ketone-alcohols, preferably acetone, methyl ether ketone, cyclohexanone and diacetone alcohol; water- miscible ethers, preferably tetrahydrofuran and dioxane; diols, preferably diols having from 2 to 12 carbon atoms, for example pentane-1 ,5-diol, ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol and thiodiglycol and oligo- and poly-alkyleneglycols, preferably diethylene glycol, triethylene glycol, polyethylene glycol and polypropylene glycol; triols, preferably glycerol and 1 ,2,6-hexanetriol; mono-C-u-alkyl ethers of diols, preferably mono-C-_M-alkyl ethers of diols haying 2 to 12 carbon atoms, especially 2-methoxyethanol, 2-(2- methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)-ethanol, 2-[2-(2- methoxyethoxy)ethoxy]ethanol, 2-[2-(2-ethoxyethoxy)-ethoxy]-ethanol and ethylene glycol monoallyl ether; cyclic amides, preferably 2-pyrrolidone, N-methyl-2- pyrrolidone, N-ethyl-2-pyrrolidone, caprolactam and 1 ,3-dimethylimidazolidone; cyclic esters, preferably caprolactone; sulfoxides, preferably dimethyl sulfoxide; and sulfones. Preferably the liquid medium comprises water and 2 or more, especially from 2 to 8, water-miscible organic solvents.

Especially preferred water-miscible organic solvents are cyclic amides, especially 2-pyrrolidone, N-methyl-pyrrolidone and N-ethyl-pyrrolidone; diols, especially 1 ,5-pentane diol, ethylene glycol, thiodiglycol, diethylene glycol and triethylene glycol; and mono-C-_M-alkyl and C-^-alkyl ethers of diols, more preferably mono- Ci^-alkyl ethers of diols having 2 to 12 carbon atoms, especially 2-methoxy-2-ethoxy-2-ethoxyethanol. Examples of further suitable liquid media comprising a mixture of water and one or more organic solvents are described in US 4,963,189, US 4,703,113, US 4,626,284 and EP-A-425,150.

When the liquid medium comprises organic solvent free from water, (i.e. less than 1% water by weight) the solvent preferably has a boiling point of from 30° to 200°C, more preferably of from 40° to 150°C, especially from 50 ° to 125°C. The organic solvent may be water-immiscible, water-miscible or a mixture of such solvents. Preferred water-miscible organic solvents are any of the hereinbefore- described water-miscible organic solvents and mixtures thereof. Preferred water- immiscible solvents include, for example, aliphatic hydrocarbons; esters, preferably ethyl acetate; chlorinated hydrocarbons, preferably CH₂CI₂; and ethers, preferably diethyl ether; and mixtures thereof.

When the liquid medium comprises a water-immiscible organic solvent, preferably a polar solvent is included because this enhances solubility of the mixture of phthalocyanine dyes in the liquid medium. Examples of polar solvents include Ci-₄-alcohols.

In view of the foregoing preferences it is especially preferred that where the liquid medium is organic solvent free from water it comprises a ketone (especially methyl ethyl ketone) and/or an alcohol (especially a d-₄-alkanol, more especially ethanol or propanol).

The organic solvent free from water may be a single organic solvent or a mixture of two or more organic solvents. It is preferred that when the liquid medium is organic solvent free from water it is a mixture of 2 to 5 different organic solvents. This allows a liquid medium to be selected that gives good control over the drying characteristics and storage stability of the ink.

Liquid media comprising organic solvent free from water are particularly useful where fast drying times are required and particularly when printing onto hydrophobic and non-absorbent substrates, for example plastics, metal and glass. The liquid media may of course contain additional components conventionally used in ink-jet printing inks, for example viscosity and surface tension modifiers, corrosion inhibitors, biocides, kogation reducing additives and surfactants which may be ionic or non-ionic.

Although not usually necessary, further colorants may be added to the ink to modify the shade and performance properties. Examples of such colorants include C.I. Direct Yellow 86, 132, 142 and 173; C.I. Direct Blue 307; C.I. Food Black 2; C.I. Direct Black 168 and 195; and C.I. Acid Yellow 23.

It is preferred that the composition according to the invention is ink suitable for use in an ink-jet printer. Ink suitable for use in an ink-jet printer is ink which is able to repeatedly fire through an ink-jet printing head without causing blockage of the fine nozzles. To do this the ink must be particle free, stable (i.e. not precipitate on storage), free from corrosive elements (e.g. chloride) and have a viscosity which allows for good droplet formation at the print head.

Ink suitable for use in an ink-jet printer preferably has a viscosity of less than 20 cP, more preferably less than 10 cP, especially less than 5 cP, at 25°C.

Ink suitable for use in an ink-jet printer preferably contains less than

500ppm, more preferably less than 250ppm, especially less than 100ppm, more especially less than 10ppm in total of divalent and trivalent metal ions (other than any divalent and trivalent metal ions bound to a colorant of Formula (1 ) or any other colorant or additive incorporated in the ink).

Preferably ink suitable for use in an ink-jet printer has been filtered through a filter having a mean pore size below 10μm, more preferably below 3μm, especially below 2μm, more especially below 1μm. This filtration removes particulate matter that could otherwise block the fine nozzles found in many ink-jet printers.

Preferably ink suitable for use in an ink-jet printer contains less than 500ppm, more preferably less than 250ppm, especially less than 100ppm, more especially less than 10ppm in total of halide ions.

A third aspect of the invention provides a process for forming an image on a substrate comprising applying a composition, preferably ink suitable for use in an ink-jet printer, according to the second aspect of the invention, thereto by means of an ink-jet printer. The ink-jet printer preferably applies the ink to the substrate in the form of droplets that are ejected through a small orifice onto the substrate. Preferred ink-jet printers are piezoelectric ink-jet printers and thermal ink-jet printers. In thermal ink- jet printers, programmed pulses of heat are applied to the ink in a reservoir by means of a resistor adjacent to the orifice, thereby causing the ink to be ejected from the orifice in the form of small droplets directed towards the substrate during relative movement between the substrate and the orifice. In piezoelectric ink-jet printers the oscillation of a small crystal causes ejection of the ink from the orifice. Alternately the ink can be ejected by an electromechanical actuator connected to a moveable paddle or plunger, for example as described in International Patent Application WO00/48938 and International Patent Application WO00/55089.

The substrate is preferably paper, plastic, a textile, metal or glass, more preferably paper, an overhead projector slide or a textile material, especially paper.

Preferred papers are plain or treated papers which may have an acid, alkaline or neutral character. Glossy papers are especially preferred. Photographic quality papers are especially preferred.

A fourth aspect of the present invention provides a material preferably paper, plastic, a textile, metal or glass, more preferably paper, an overhead projector slide or a textile material, especially paper more especially plain, coated or treated papers printed with a compound as described in the first aspect of the invention, a composition according to the second aspect of the invention or by means of a process according to the third aspect of the invention.

It is especially preferred that the printed material of the fourth aspect of the invention is a print on a photographic quality paper printed using a process according to the third aspect of the invention.

A fifth aspect of the present invention provides an ink-jet printer cartridge comprising a chamber and a composition, preferably ink suitable for use in an ink- jet printer, wherein the composition is in the chamber and the composition is as defined and preferred in the second aspect of the present invention. The cartridge may contain a high concentration ink and a low concentration ink, as described in the second aspect of the invention, in different chambers.

Example 1 Preparation of

A solution of cyanuric chloride (3.37g) in acetone (25ml) was added drop- wise to a cooled (0-5⁰C), stirred solution of CuPc-(CH₂NH₂)₄.4HCI (4.5g, prepared as described in Example 30 of US 2,761 ,868) in distilled water (100 ml) at pH 5.5- 6 (2N NaOH). The reaction mixture was stirred for 4 hours and then a solution of taurine (2.52g) in distilled water (40ml) was added. The pH of the reaction mixture was maintained at 7 to 7.5 (2N NaOH) and the mixture was stirred overnight, during which time it warmed up to room temperature. A solution of taurine (7.56g) in distilled water (40ml) was then added and the reaction mixture was heated, with stirring, at 8O⁰C and pH 9.5 to 10 (2N NaOH) for 4 hours. The mixture was filtered (GF/F) while hot and the solution was allowed to cool overnight. The pH of the solution was then lowered to 1.5 (cHCI) and the product was precipitated by the addition of sodium chloride (20% w/v). The product was filtered off, washed with acidified saturated brine and redissolved in water. The solution was dialysed, filtered (GF/F) and dried at 5O⁰C in an oven to yield 3.5g of product.

Comparative Dye

The comparative dye was C.I. Direct Blue 199 obtained as Pro-jet^R™ Cyan 1 from Fujifilm Imaging Colorants Ltd, as supplied this is a compound of Formula:

C.I. Direct Blue 199 is the most widely used cyan ink-jet dye.

Example 2

Ink

Ink was prepared from the dye of Example 1 and the Comparative Dye by dissolving 3.5g of the dye in 96.5ml of a liquid medium consisting of 7 parts 2- pyrrolidone; 7 parts diethylene glycol; 7 parts ethylene glycol; 1 part Surfynol^R™ 465; 0.2 parts Tris buffer and the balance deionised water and adjusting the pH to between pH 8 to 8.5 with sodium hydroxide. Surfynol^R™ 465 is a surfactant from Air Products.

Example 3 Ink-jet Printing

Ink, prepared as described above, was filtered through a 0.45 micron nylon filter and then incorporated into an empty print cartridge using a syringe.

These inks were the printed on to the following media at 50% depth percent:

Canon Premium PR101 Photo Paper (PR101 ); and Epson Ultra Premium Glossy Photo Paper (SEC PM)

Print Evaluation Prints, formed by ink-jet printing, were tested for ozone fastness by exposure to 5ppm ozone at 25°C, 50% relative humidity, for 24hrs in a Hampden 903 Ozone cabinet. Fastness of the printed ink to ozone was judged by the difference in the optical density before and after exposure to ozone.

Optical density measurements were performed using a Gretag spectrolino spectrophotometer set to the following parameters :

Measuring Geometry 0°/45° Spectral Range 380 - 730nm Spectral Interval 10nm llluminant D65 Observer 2° (CIE 1931 )

Density Ansi A External Filler None

Ozone fastness was assessed by the percentage change in the optical density of the print, where a lower figure indicates higher fastness, and the degree of fade. The degree of fade is expressed as ΔE and a lower figure indicates higher light fastness. ΔE is defined as the overall change in the CIE colour coordinates L, a, b of the print and is expressed by the equation ΔE = (ΔL² + Δ a² + Δb² )^α5. Ozone Fastness

Clearly dyes according to the present invention, when printed, display an enhanced ozone fastness compared to the market leading cyan dye.

Further Inks

The inks described in Tables A and B may be prepared using the Compound described in the above Example as a dye. Numbers quoted refer to the number of parts of the relevant ingredient and all parts are by weight. The inks may be applied to paper or a specialist ink-jet media by ink-jet printing.

The following abbreviations are used in Tables A and B:

PG = propylene glycol

DEG = diethylene glycol NMP = N-methyl pyrrolidone

DMK = dimethylketone

IPA = isopropanol

MEOH = methanol

2P = 2-pyrrolidone MIBK = methylisobutyl ketone

P12 = propane-1 ,2-diol

BDL = butane-2,3-diol

CET= cetyl ammonium bromide

PHO = Na₂HPO₄ and TBT = tertiary butanol

TDG = thiodiglycol

TABLE B

Ol

Claims

1. A compound of Formula (1 ) and salts thereof:

MPc - (R¹-NR²-R³)_n

Formula (1 ) wherein:

M is Cu or Ni;

Pc represents a phthalocyanine nucleus of formula;

R¹ is optionally substituted

R² is H or optionally substituted Ci^alkyl; R³ is optionally substituted alkyl, optionally substituted aryl, optionally substituted acyl or optionally substituted heterocyclyl; or

R² and R³ are joined together to form with the nitrogen a heterocyclic ring which may contain other heteroatoms; n is 1 to 8: and provided that at least one of R¹, R² and R³ carries at least one acidic water solubilising substituent selected from the group consisting of -SOsH, -CO₂H and -PO₃H₂.

2. A compound and salts thereof as claimed in claim 1 wherein M is Cu.

3. A compound and salts thereof as claimed in either claim 1 or claim 2 wherein R¹ is unsubstituted C-^alkylene.

4. A compound and salts thereof as claimed in any one of the preceding claims wherein R¹ is methylene.

5. A compound and salts thereof as claimed in any one of the preceding claims wherein R² is H or methyl.

6. A compound and salts thereof as claimed in any one of the preceding claims wherein R³ is optionally substituted Ci.i₂alkyl, optionally substituted aryl or optionally substituted heteroaryl.

7. A compound and salts thereof as claimed in any one of the preceding claims wherein R³ is optionally substituted Ci_-8alkyl substituted with at least one acidic water solubilising substituent selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂; optionally substituted C_1-8alkyl substituted with an optionally substituted heteroaryl; or optionally substituted C_1-8alkyl substituted with optionally substituted phenyl.

8. A compound and salts thereof as claimed in any one of the preceding claims wherein R³ is C-i^alkyl carrying 1 or 2 acidic water solubilising substituents selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂;

carrying an optionally substituted heteroaryl where the heteroaryl group or substituent thereof carries at least one acidic water solubilising substituent selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂; or Ci^alkyl carrying an optionally substituted phenyl group where the phenyl group or substituent thereof carries at least one acidic water solubilising substituent selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂.

9. A compound and salts thereof as claimed in any one of the preceding claims wherein R³ is optionally substituted C-i^alkyl carrying an optionally substituted triazinyl which carries either directly or on a substituent an acidic water solubilising substituent selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂.

10. A compound and salts thereof as claimed in claim 9 wherein the optionally substituted triazinyl substituent on the optionally substituted C^alkyl of R³ is a group of Formula (2)

Formula (2) wherein: X is selected from the group consisting of -OR⁴, -SR⁴, -NR⁴R⁵; Y is selected from the group consisting of -OR⁶, -SR⁶, -NR⁶R⁷; R⁴, R⁵, R⁶ and R⁷ are independently H, optionally substituted alkyl, optionally substituted aryl or optionally substituted heterocyclyl provided that at least one of the groups represented by R⁴, R⁵, R⁶ and R⁷ carries at least one acidic water solubilising substituent selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂.

11. A compound and salts thereof as claimed in either claim 9 or claim 10 wherein the triazinyl substituent on the optionally substituted C_1-4alkyl of R³ is a group of Formula (3)

Formula (3) wherein:

R F ⁸ is H or optionally substituted Ci_-4alkyl;

R⁹ is H or optionally substituted d^alkyl; R¹⁰ is H or optionally substituted Ci^alkyl;

12. A compound and salts thereof as claimed in claim 1 wherein the compound of Formula (1 ) is of Formula (4) and salts thereof

Formula (4) wherein:

Pc represents a phthalocyanine nucleus; R¹² is C_1-4alkylene; R¹³, R¹⁴ and R¹⁶ are each independently H or methyl;

R¹⁵ and R¹⁷ are independently Ci^alkyl carrying 1 to 3 acidic water solubilising substituents selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂ and optionally other substituents or aryl carrying 1 to 3 acidic water solubilising substituents selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂ and optionally other substituents; and n is 1 to 4.

13. A composition comprising a compound of Formula (1 ) as described any one of claims 1 to 12 and a liquid medium.

14. A composition as claimed in claim 12 wherein the liquid medium comprises a mixture of water and organic solvent or organic solvent free from water.

15. A composition as claimed in either claim 13 or claim 14 which is ink suitable for use in an ink-jet printer.

16. A process for forming an image on a substrate comprising applying ink suitable for use in an ink-jet printer, according to claim 15, thereto by means of an ink-jet printer.

17. A material printed by means of a process according to claim 16.

18. An ink-jet printer cartridge comprising a chamber and ink suitable for use in an ink-jet printer, according to claim 15, wherein the composition is in the chamber.