WO2008110747A1

WO2008110747A1 - Phthalocvanines and their use in ink-jet printing

Info

Publication number: WO2008110747A1
Application number: PCT/GB2008/000743
Authority: WO
Inventors: Neil James Thompson
Original assignee: Fujifilm Imaging Colorants Limited
Priority date: 2007-03-15
Filing date: 2008-03-05
Publication date: 2008-09-18
Also published as: GB0914159D0; GB0704970D0; GB2459596A

Abstract

A mixture of com ounds of Formula (1) and salts thereof: wherein: M is 2H, Si, a metal, an oxymetal group, a hydroxymetal group or a halometal group; Pc represents an phthalocyanine nucleus of formula (1a); R1 is H or optionally substituted C1-4alkyl; R2 is H or optionally substituted C1-8alkyl; R3 is H or optionally substituted hydrocarbyl; and R4 is optionally substituted hydrocarbyl; or R3 and R4 together with the nitrogen atom to which they are attached represent an optionally substituted aliphatic or aromatic ring system; each R5 is independently H or optionally substituted C1-4alkyl, provided that at least one R5 is optionally substituted C1-4alkyl; x is 0 to 4; y is 0 to 4; z is greater than 0 to 4; the sum of x+y+z is in the range of from 2 to 4; and the substituents, represented by x, y and z, are attached only to a β-position on the phthalocyanine ring and the substituents represented by y and z are different. Also compositions, inks, printing processes, printed materials and ink-jet cartridges.

Description

Phthalocvanines 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 it is becoming increasingly common for consumers to print off photographs using an ink-jet printer.

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 display bronzing or 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 seem to be 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 mixture of compounds of Formula (1) and salts thereof:

Formula (1) wherein:

M is 2H, Si, a metal, an oxymetal group, a hydroxymetal group or a halometal group;

Pc represents an phthalocyanine nucleus of formula;

R¹ is H or optionally substituted Ci_-4alkyl;

R² is H or optionally substituted C_halky!;

R³ is H or optionally substituted hydrocarbyl; and

R⁴ is optionally substituted hydrocarbyl; or

R³ and R⁴ together with the nitrogen atom to which they are attached represent an optionally substituted aliphatic or aromatic ring system; each R⁵ is independently H or optionally substituted Ci_₄alkyl, provided that at least one R⁵ is optionally substituted Ci_-4alkyl; x is 0 to 4; y is 0 to 4; z is greater than 0 to 4; the sum of x+y+z is in the range of from 2 to 4; and the substituents, represented by x, y and z, are attached only to a β-position on the phthalocyanine ring and the substituents represented by y and z are different.

M is preferably 2Li, 2Na, 2K, Mg, Ca, Ba, Al, Si, Sn, Pb, Rh, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, AIX, GaX, InX or SiX₂, where in X is OH or Cl, more preferably Sc, Ti, Va, Cr, Mn, Fe, Co, Zn, Ni and Cu, especially Cu or Ni and more especially Cu.

In a first embodiment at least one of R¹ and R² is optionally substituted Ci- ₄alkyl carrying at least one water solubilising substituent preferably selected from the group consisting of: -OH, -SO₃H, -CO₂H and -PO₃H₂. In the first embodiment if one of R¹ and R² is not optionally substituted C_1-4alkyl carrying at least one water solubilising substituent then it is H or optionally substituted C_1-4alkyl, preferably H or methyl, especially H. In a second embodiment R¹ and R² independently are H or methyl and more preferably R¹ and R² are both H.

In a third embodiment at least one of R¹ and R² is optionally substituted C_1- ₄alkyl with a phenyl substituent carrying 1 or 2, particularly 2, water solubilising groups, especially water solubilising groups selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂ and more especially -SO₃H and -CO₂H. In the third embodiment if one of R¹ and R² is not optionally substituted Ci_-4alkyl with a phenyl substituent carrying 1 or 2 water solubilising groups then it is H or optionally substituted Ci_-4alkyl, preferably H or methyl and especially H. In a fourth preferred embodiment R¹ is H or optionally substituted Ci_-4alkyl

(preferably H or methyl and especially H) and R² is C-i-salkyl substituted with 2 or more water solubilising groups, especially water solubilising groups selected from the group consisting of -OH, -SO₃H, -CO₂H, and -PO₃H₂. In the fourth preferred embodiment it is especially preferred that R² is C_1-8alkyl substituted with 2 or more, preferably 4 or more, -OH groups and optionally other substituents, especially substituents selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂.

Preferably R³ is H, optionally substituted alkyl, optionally substituted heterocyclyl or optionally substituted aryl.

More preferably R³ is H or optionally substituted C-|.₈alkyl especially Ci- salkyl substituted with 1 or more substituents selected from; water solubilising groups, optionally substituted heteroaryl or optionally substituted phenyl.

It is particularly preferred that R³ is H; C-i^alkyl carrying 1 or 2, particularly

2, water solubilising groups selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂; Ci_-4alkyl carrying an optionally substituted heteroaryl (where preferably the heteroaryl group or substituent thereof carries at least one water solubilising group selected from the group consisting of -SO₃H, -CO₂H and -

PO₃H₂); or C_1-4alkyl carrying an optionally substituted aryl group (where preferably the aryl group or substituent thereof carries at least one water solubilising group selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂). Preferably R⁴ is optionally substituted alkyl, optionally substituted heterocyclyl or optionally substituted aryl.

More preferably R⁴ is optionally substituted C-i-salkyl especially Ci_-8alkyl substituted with 1 or more substituents selected from; water solubilising groups selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂, optionally substituted heteroaryl or optionally substituted phenyl.

It is particularly preferred that R⁴ is Ci_-4alkyl carrying 1 or 2, particularly 2, water solubilising groups selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂; C-i_-4alkyl carrying an optionally substituted heteroaryl (where preferably the heteroaryl group or substituent thereof carries at least one water solubilising group selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂); or C₁. 4alkyl carrying an optionally substituted phenyl group (where preferably the phenyl group or substituent thereof carries at least one water solubilising group selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂). It is especially preferred that R⁴ is optionally substituted Ci_-4alkyl carrying an optionally substituted triazinyl (where preferably the triazinyl group or substituent thereof carries at least one water solubilising group selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂).

Preferably the optionally substituted triazinyl substituent on R⁴ when it is optionally substituted Ci_₄alkyl is a group of Formula (2)

Formula (2) wherein: X is selected from the group consisting of -OR⁶, -SR⁶, -NR⁶R⁷;

Y is selected from the group consisting of -OR⁸, -SR⁸, -NR⁸R⁹; R⁶, R⁷, R⁸ and R⁹ are independently H, optionally substituted alkyl, optionally substituted aryl or optionally substituted heterocyclyl provided that at least one of the groups represented by R⁶, R⁷, R⁸ and R⁹ carries at least one 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.

More preferably the optionally substituted triazinyl substituent on R⁴ when it is optionally substituted Ci_-4alkyl comprises a group of Formula (3)

Formula (3) wherein:

R¹⁰ is H or optionally substituted C^alkyl; R¹¹ is H or optionally substituted Ci_-4alkyl; R¹² is H or optionally substituted Ci_-4alkyl; R¹³ is optionally substituted alkyl, optionally substituted aryl or optionally substituted heterocyclyl carrying at least one substituent selected from the group consisting Of -SO₃H, -CO2H and -PO₃H2. Preferably R¹⁰ is H or unsubstituted Ci_-4alkyl, more preferably R¹⁰ is H or methyl especially H. Preferably R¹¹ is H or unsubstituted Ci_-4alkyl, more preferably R¹¹ is H or methyl especially H.

Preferably R¹² is H or unsubstituted Ci_-4alkyl, more preferably R¹² is H or methyl especially H.

In a preferred embodiment R¹⁰, R¹¹ and R¹² are all independently either H or methyl, more preferably R¹⁰, R¹¹ and R¹² are all H.

Preferably R¹³ is optionally substituted aryl carrying at least one substituent selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂. More preferably R¹³ is an aryl group (particularly a phenyl group) carrying 1 to 3, especially 2, - SO₃H groups. In one preferred embodiment all the R⁵ groups are independently optionally substituted C-ualkyl, more preferably all the R⁵ groups are independently unsubstituted Ci_-4alkyl, especially methyl.

In a second preferred embodiment in each constituent ring of the phthalocyanine one R⁵ group is H and the other is optionally substituted C-i^alkyl, preferably unsubstituted Ci_₄alkyl and especially methyl. Preferably x is 0.1 to 3, more preferably 0.2 to 2.0. Preferably y is 0.1 to 3, more preferably 0.2 to 2.0.

Preferably z is 0.1 to 3.5, more preferably 0.5 to 3, especially 0.8 to 3.0 and more especially 1.0 to 3. In one preferred embodiment x is greater than 1.

In another preferred embodiment y is less than 1 and preferably less than 0.5.

In a third preferred embodiment z is less than 1 and preferably less than 0.3. In a fourth preferred embodiment z is greater than 3 and more preferably greater than 3.5.

In a fifth preferred embodiment x and y are both 0 while z is 2 to 4, more preferably 3 to 4 and especially 4. The sum of (x+y+z) is preferably 3 to 4, more preferably the sum of (x+y+z) is 4.

One particularly preferred mixture of compounds of Formula (1) is of Formula (4) and salts thereof

Formula (4) wherein:

Pc(alkyl) represents an alkyl phthalocyanine nucleus of formula;

each R⁵ is independently H or methyl, provided that at least one R⁵ is methyl;

R¹⁴ is H or optionally substituted C_halky!; R¹⁵, R¹⁶, R¹⁷, R¹⁷, R¹⁸, R¹⁹ and R²¹ are each independently H or methyl;

R²⁰ is aryl carrying 1 to 3 substituents selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂ and other optional substituents; L is optionally substituted C-^alkylene; x, y, and z are each independently greater than 0 and less than 4 x+y+z is in the range of 3 to 4; and the substituents represented by x, y and z are attached to the phthalocyanine nucleus by a β-position.

Preferably R¹⁴ is H, methyl, optionally substituted C_1-4alkyl carrying at least one water solubilising substituent preferably selected from the group consisting of:

-SO₃H, -OH, -CO₂H and -PO₃H₂, C-ι_-4alkyl with a phenyl substituent carrying 1 or 2, particularly 2, water solubilising groups, especially water solubilising groups selected from: -SO₃H, -CO₂H and -PO₃H₂ and more especially -SO₃H, -CO₂H; or Ci_-8alkyl substituted with 2 or more, preferably 4 or more, -OH groups and optionally other substituents, especially substituents selected from the group consisting of -SO₃H, -CO₂H, and -PO₃H₂. Preferably R²⁰ is optionally substituted aryl carrying 1 or 2 substituents selected from the group consisting of -SO₃H, - CO₂H, and -PO₃H₂.

In one preferred embodiment R¹⁵, R¹⁶, R¹⁷, R¹⁸, R¹⁹ and R²¹ are all H.

Preferably L is unsubstituted C-^alkylene, especially -C₂H₄-.

A second particularly preferred mixture of compounds of Formula (1 ) is of Formula (5) and salts thereof:

CuPc(alkyl)— (SO₂NR²¹ R²²)z

Formula (5) wherein:

Pc(alkyl) represents an alkyl phthalocyanine nucleus of formula;

R²¹ is H or optionally substituted Ci_-4alkyl;

R²² is optionally substituted Ci_-4alkyl carrying a water solubilising group selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂; and z is in the range of greater than zero to 4.

Preferred optional substituents which may be present on any one of L, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², R¹³, R¹⁴, R²⁰, R²¹ and R²² are independently selected from: optionally substituted alkoxy (preferably Ci_-4-alkoxy), 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 Ci_-4-alkyl). When L, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², R¹³, R¹⁴, R²⁰, R²¹ and R²² comprise a cyclic group they may also carry an optionally substituted alkyl (especially Ci_-4-alkyl) substituent. Optional substituents for any of the substituents described for L, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², R¹³, R¹⁴, R²⁰, R²¹ and R²² may be selected from the same list of substituents.

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 hydroxy! 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 ((CHs)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 as isomers and in tautomeric forms other than those shown in this specification. These isomers and tautomers are included within the scope of the present invention.

The mixtures of compounds of Formula (1) may be prepared by any method known in the art, and particularly by any method which comprises cyclisation of appropriate α-alkylated- or α-dialkylated- ; phthalic acid, phthalonitrile, iminoisoindoline, phthalic anhydride, phthalimide or phthalamide in the presence of a suitable nitrogen source (if required), a metal salt, such as CuCb, (if required) and a base such as 1 ,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The α-alkylated -phthalocyanine so formed may then be chlorosulfonated in the unsubstituted β-position by reacting with, for example, chlorosulfonic acid and optionally a chlorinating agent (e.g. POCI₃, PCI₅ or thionyl chloride). The sulfonyl chloride groups so formed are reacted with compounds of formula HNR¹R² and HNR³R⁴ wherein R¹, R², R³ and R⁴ are as hereinbefore defined. This reaction is preferably performed in water at a pH above 7. Typically the reaction is performed at a temperature of 30 to 70°C and is usually complete in less than 24 hours. The compounds of formula HNR¹R² and HNR³R⁴ may be used as a mixture or added sequentially.

Many of the compounds of formula HNR¹R² and HNR³R⁴ are commercially available, for example for ammonia or taurine, others may be made easily by a skilled person using methods which are well known in the art.

The ratio of sulfo to different sulfonamide substituents may be varied by varying the nature and amount of chlorinating agent used, the relative amounts of compounds of formula HNR¹R² and HNR³R⁴ used and the reaction conditions in both reactions.

A skilled person will appreciate that the product of these reactions will be a disperse mixture and so the values of x, y and z will represent an average of the groups present in the mixture.

The compounds of Formula (1) have attractive, strong 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 mixture of compounds of Formula (1) and salts thereof 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 mixture of compounds 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 20⁰C 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 ink, a low concentration 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 C-i-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^-alkyl ethers of diols, preferably mono-C_1-4-alkyl ethers of diols having 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 monoally! 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-ι_-4-alkyl and Ci_-4-alkyl ethers of diols, more preferably mono- Ci-₄-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 CH₂Cl₂; 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 C-ι-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 lOOppm, 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 mixture of compounds 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

CuPc-α-(CH₃)₈-β-(Sθ₂NHCH₂CH₂Sθ₃H)₄ Stage 1

Preparation of dimethyl phthalonitrile

The dimethyl phthalonitrile intermediate was prepared as described by N. B. McKeown, I. Chambrier and M. J. Cook, J. Chem. Soc, Perkin Trans. 1, 1990, 1169-1177.

LiN(SiMe₃).,

Stage 2

Preparation of copper α-octamethyl phthalocyanine Copper α-octamethyl phthalocyanine was prepared from the dimethyl phthalonitrile intermediate prepared in stage 1 as described in; D. Wδhrle, G. Schnurpfeil, G. Knothe, Dyes and Pigments 1992, 18, 91-102.

Stage 3 Preparation of

CuPc-α-(CH₃)8-β-(SO₂CI)₄

Phosphorus oxychloride (9.3 g) was added drop-wise over 15 min to stirred chlorosulphonic acid (54 ml) at room temperature. The mixture was stirred for 10 min and copper α-octamethyl phthalocyanine (13.5 g) from stage 2 was added portion-wise to the reaction mixture over 20 min. The reaction mixture was stirred and heated at 15O⁰C for 6 h and allowed to cool down to room temperature overnight. The reaction mixture was then added drop-wise with care to a stirred mixture of ice/water (500 ml) and the temperature was maintained below 1O⁰C in an ice bath. The mixture was stirred for 15 min and the solid was filtered off, washed with water (300 ml) and dried at the pump.

Stage 4 Preparation of the title compound

Half of the sulfonyl chloride prepared in stage 3 suspended in water (200 ml) was added to a cooled (<10°C), stirred solution of taurine (6.25 g) in water (200 ml) at pH 9.5 (2M NaOH). The pH of the reaction was maintained at 9.5 with 2M NaOH and the reaction mixture was stirred overnight and allowed to warm up to room temperature. The reaction mixture was then heated at 6O⁰C for 1 h and allowed to cool to room temperature. The solution was then filtered and the volume reduced to 130 ml. The resultant product was salted out with lithium chloride (20% w/v), filtered off and washed with 30% aqueous lithium chloride (50 ml). The solid was then dissolved in water (150 ml) and the solution was dialysed and then dried overnight in an oven at 5O⁰C.

Example 2

CuPc-α-(CH₃)₈-β-(SO₂NHCH₂CH₂Sθ₃H)₂(SO₂NH₂)₁(SO₃H)₁

Stages 1 to 3 were carried out as described in Example 1. Half of the sulfonyl chloride prepared in stage 3, suspended in water, was added to a cooled (<10°C), stirred solution of taurine (2.75 g) and ammonium chloride (1.38 g) in water (200 ml) at pH 9.5 (adjusted with 2M NaOH). The pH of the reaction mixture was kept at 9.5 with 2M NaOH and the mixture was stirred overnight and allowed to warm up to room temperature. The reaction mixture was then heated at 6O⁰C for 1 h and then allowed to cool down to room temperature. The solution was filtered and dried overnight at 5O⁰C. The solid was dissolved in water (150 ml) and the product was salted out with lithium chloride (15% w/w). The solid was filtered off, dissolved in water (200 ml) and the resultant solution was dialysed and then dried overnight in an oven at 5O⁰C.

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 3

Ink Preparation

Ink was prepared from the dye of Examples 1 and 2 and the Comparative

Dye by dissolving 3.5 g of the dye in 96.5 ml 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 4 Ink-iet 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 25⁰C, 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 = (Δl_² + Δ a² + Δb² )⁰-⁵. Ozone Fastness

Clearly dyes according to the present invention 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 Example 1 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 specialist ink-jet media by an ink-jet printer.

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

CD

Claims

1. A mixture of compounds of Formula (1 ) and salts thereof:

Formula (1) wherein:

Pc represents an phthalocyanine nucleus of formula;

R¹ is H or optionally substituted Ci_-4alkyl;

R² is H or optionally substituted C-|.₈alkyl;

R³ is H or optionally substituted hydrocarbyl; and

R⁴ is optionally substituted hydrocarbyl; or

R³ and R⁴ together with the nitrogen atom to which they are attached represent an optionally substituted aliphatic or aromatic ring system; each R⁵ is independently H or optionally substituted Ci_-4alkyl, provided that at least one R⁵ is optionally substituted C-i_-4alkyl; x is 0 to 4; y is 0 to 4; z is greater than 0 to 4; the sum of x+y+z is in the range of from 2 to 4; and the substituents, represented by x, y and z, are attached only to a β-position on the phthalocyanine ring and the substituents represented by y and z are different.

2. A mixture of compounds of Formula (1) and salts thereof as claimed in claim 1 wherein M is Ni or Cu.

3. A mixture of compounds of Formula (1 ) and salts thereof as claimed in either claim 1 or claim 2 wherein at least one of R¹ and R² is optionally substituted

C_1-4alkyl carrying at least one water solubilising substituent selected from the group consisting of: -OH, -SO₃H, -CO₂H and -PO₃H₂.

4. A mixture of compounds of Formula (1 ) and salts thereof as claimed in either claim 1 or claim 2 wherein R¹ and R² independently are H or methyl.

5. A mixture of compounds of Formula (1) and salts thereof as claimed in either claim 1 or claim 2 wherein at least one of R¹ and R² is optionally substituted C-|,₄alkyl with a phenyl substituent carrying 1 or 2 water solubilising groups selected from the group consisting of -SO₃H, -CO₂H and -PO₃H.

6. A mixture of compounds of Formula (1) and salts thereof as claimed in either claim 1 or claim 2 wherein R² is Ci_-8alkyl substituted with 2 or more water solubilising groups selected from the group consisting of -OH, -SO₃H, -CO₂H, and -PO₃H₂.

7. A mixture of compounds of Formula (1 ) and salts thereof as claimed in any one of claims 1 to 6 wherein R³ is H, optionally substituted alkyl, optionally substituted heterocyclyl or optionally substituted aryl.

8. A mixture of compounds of Formula (1) and salts thereof as claimed in claim 7 wherein R³ is H or optionally substituted Ci_-8alkyl.

9. A mixture of compounds of Formula (1) and salts thereof as claimed in claim 7 or claim 8 wherein R³ is H; Ci_-4alkyl carrying 1 or 2 water solubilising groups selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂; Ci_-4alkyl carrying an optionally substituted heteroaryl group; or

carrying an optionally substituted aryl group.

10. A mixture of compounds of Formula (1 ) and salts thereof as claimed in any one of claims 1 to 9 wherein R⁴ is optionally substituted alkyl, optionally substituted heterocyclyl or optionally substituted aryl.

11. A mixture of compounds of Formula (1 ) and salts thereof as claimed in claim 10 wherein R⁴ is optionally substituted C_1-8alkyl substituted with 1 or more substituents selected from the group consisting of -SO₃H, -CO₂H and -PO₃H₂; optionally substituted heteroaryl; or optionally substituted phenyl.

12. A mixture of compounds of Formula (1) and salts thereof as claimed in either claim 10 or claim 11 wherein R⁴ is C-i_-4alkyl carrying 1 or 2 water solubilising groups selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂; Ci_-4alkyl carrying an optionally substituted heteroaryl where the heteroaryl group or substituent thereof carries at least one water solubilising group selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂; or Ci_-4alkyl carrying an optionally substituted phenyl group where the phenyl group or substituent thereof carries at least one water solubilising group selected from the group consisting of -SO₃H, - CO₂H and -PO₃H₂.

13. A mixture of compounds of Formula (1 ) and salts thereof as claimed in any one of claims 10 to 12 wherein R⁴ is optionally substituted Ci_-4alkyl carrying an optionally substituted triazinyl.

14. A mixture of compounds of Formula (1) and salts thereof as claimed in claim 13 wherein the optionally substituted triazinyl substituent on R⁴ when it is optionally substituted Ci_-4alkyl is a group of Formula (2).

Formula (2) wherein:

X is selected from the group consisting of -OR⁶, -SR⁶, -NR⁶R⁷;

Y is selected from the group consisting of -OR⁸, -SR⁸, -NR⁸R⁹;

R⁶, R⁷, R⁸ and R⁹ are independently H, optionally substituted alkyl, optionally substituted aryl or optionally substituted heterocyclyl provided that at least one of the groups represented by R⁶, R⁷, R⁸ and R⁹ carries at least one substituent selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂.

15. A mixture of compounds of Formula (1 ) and salts thereof as claimed in either claim 13 or claim 14 wherein the optionally substituted triazinyl substituent on R⁴ when it is optionally substituted C_1-4alkyl comprises a group of Formula (3)

Formula (3) wherein:

R¹⁰ is H or optionally substituted C_1-4alkyl;

R¹¹ is H or optionally substituted Ci_-4alkyl; R¹² is H or optionally substituted Ci_-4alkyl;

R¹³ is optionally substituted alkyl, optionally substituted aryl or optionally substituted heterocyclyl carrying at least one substituent selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H₂.

16. A mixture of compounds of Formula (1) and salts thereof as claimed in any one of the preceding claims wherein all the R⁵ groups are methyl.

17. A mixture of compounds of Formula (1 ) and salts thereof as claimed in any one of the preceding claims wherein the sum of (x+y+z) is 3 to 4.

18. A mixture of compounds of Formula (1 ) and salts thereof as claimed in claim 1 of Formula (4) and salts thereof

Formula (4) wherein:

Pc(alkyl) represents an alkyl phthalocyanine nucleus of formula;

each R⁵ is independently H, Cl or methyl, provided that at least one R⁵ is Cl or methyl; R¹⁴ is H or optionally substituted C_1-8alkyl;

R¹⁵, R¹⁶, R¹⁷, R¹⁷, R¹⁸, R¹⁹ and R²¹ are each independently H or methyl;

R²⁰ is aryl carrying 1 to 3 substituents selected from the group consisting of -SO3H, -CO₂H and -PO₃H₂ and other optional substituents;

L is optionally substituted C_1-4alkylene; x, y, and z are each independently greater than 0 and less than 4 x+y+z is in the range of 3 to 4; and the substituents represented by x, y and z are attached to the phthalocyanine nucleus by a β-position.

19. A mixture of compounds of Formula (1 ) and salts thereof as claimed in claim 1 of Formula (5) and salts thereof:

CuPc(alkyl)— (SO₂NR²¹R²²)z Formula (5) wherein:

Pc(alkyl) represents an alkyl phthalocyanine nucleus of formula;

each R⁵ is independently H or methyl, provided that at least one R⁵ is methyl; R²¹ is H or optionally substituted C-i_-4alkyl;

R²¹ is optionally substituted C-i_-4alkyl carrying a water solubilising group selected from the group consisting Of -SO₃H, -CO₂H and -PO₃H2; and z is greater than zero to 4.

20. A composition comprising a mixture of compounds of Formula (1 ) and salts thereof as described in any one of claims 1 to 19 and a liquid medium.

21. A composition according to claim 20 which is ink suitable for use in an ink- jet printer.

22. A process for forming an image on a substrate comprising applying a ink suitable for use in an ink-jet printer, as described in claim 21 , thereto by means of an ink-jet printer.

23. A material printed by means of a process according to claim 22.

24. An ink-jet printer cartridge comprising a chamber and ink suitable for use in an ink-jet printer as described in claim 22, wherein the ink is in the chamber.