WO2001066648A1

WO2001066648A1 - Compound, compositions and use

Info

Publication number: WO2001066648A1
Application number: PCT/GB2001/000570
Authority: WO
Inventors: Prakash Patel; Paul Wight
Original assignee: Avecia Limited
Priority date: 2000-03-07
Filing date: 2001-02-12
Publication date: 2001-09-13
Also published as: AU2001232080A1; GB0005299D0

Abstract

A compound of formula (1): Pc-SO2-L-SO2-Pc wherein each Pc is independently an optionally substituted phthalocyanine group; and L is a divalent linking group; provided that: (i) L is free from halo-s-triazine groups; and (ii) L is not -NH-CH2-CH2-NH-CH2-CH2-NH-. Inks comprising these compounds, ink jet printer cartridges containing these inks, their use in ink jet printing and substrates printed with these compounds and/or inks.

Description

COMPOUND. COMPOSITIONS AND USE

This invention relates to dyes, to compositions containing these dyes, to inks, to printing processes, to printed substrates and to ink jet printer cartridges. UP 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.

There are many demanding performance requirements for dyes and inks used in UP. For example they desirably provide sharp, non-feathered images having good water- fastness, light-fastness and optical density. The inks are often required to dry quickly when applied to a substrate to prevent smudging, but they should not form a crust over the tip of an ink jet nozzle because this will stop the printer from working. The inks should also be stable to storage over time without decomposing or forming a precipitate which could block the fine nozzle.

Dyes containing a single copper phthalocyanine group and their use in ink jet printing are known. For example, Cl Direct Blue 199 and Cl Direct Blue 86 are used as colorants in commercial ink jet printing inks. However, there is a continuing need to provide colorants having superior properties in ink jet printing inks.

According to the present invention there is provided a compound of Formula (1 ):

Pc -SO₂-L-SO₂-Pc

Formula (1 ) wherein: each Pc independently is an optionally substituted phthalocyanine group; and L is a divalent linking group; provided that:

(i) L is free from halo-s-triazine groups; and (ii) L is not -NH-CH₂-CH₂-NH-CH₂-CH₂-NH-. Preferably L is a group of Formula (2):

-NP U-NR¹-

Formula (2) wherein: R¹ is H, optionally substituted alkyl or optionally substituted aryl; and

L¹ is a divalent linking group; provided that:

(i) L is free from halo-s-triazine groups; and (ii) L is not -NH-CH₂-CH₂-NH-CH₂-CH₂-NH-. Preferably L comprises one or more carbon atoms and optionally one or more heteroatoms, preferably nitrogen, oxygen and/or sulphur. More preferably L¹ comprises from 1 to 30, especially 2 to 20 carbon atoms and 0 to 20 atoms, especially 1 to 10 atoms selected from oxygen nitrogen and sulphur. In a particularly preferred embodiment L¹ is of Formula (3):

-G-X(C_nH_2n - X)_p-G-

Formula (3) wherein: each G independently is optionally substituted alkylene or arylene; each X independently is an ester, amide, amine, sulphone, sulphoxide, ether or thioether; n is from 1 to 6; and p has a value of from 0 to 10; provided that:

(i) L is free from halo-s-triazine groups; and (ii) L is not -NH-CH₂-CH₂-NH-CH₂-CH₂-NH-.

Preferably each G independently is optionally substituted C_1-6 alkylene or optionally substituted phenylene.

Preferably each X independently is a group of formula -CO₂-, -CONR²-, -NR²-, -O-, -SO-, -SO₂- or -S- wherein R² is H or optionally substituted C_1-4 alkyl.

Preferably n is 2, 3 or 4, more preferably 2 or 3 especially 2. The value of n may vary from one group of formula (C_nH_2n - X) to another, but preferably n has the same value in all groups of formula (C_nH_2n - X).

Preferably p has a value of from 0 to 8, more preferably 0 to 6, especially 0,1 ,2,3,4 or 5.

In a preferred embodiment one G is optionally substituted phenylene and the other G is optionally substituted phenylene or optionally substituted C_1-6 alkylene and each X independently is -O-, -SO-, -SO₂- or -NR²- wherein R² is H or optionally substituted C^ alkyl, n is 2 or 3 and p is 0, 1 , 2, 3, 4 or 5.

The optional substituents which may be present on G are preferably selected from

C alkyl (especially methyl), halo (especially Cl, F or Br), CN, NO₂, SO₂F, OH,

-NR³CONR³R⁴, -NR³R⁴, -COR³, -COR³R⁴, -CO₂R³ and -SO₂R³ wherein R³ and R⁴ are each independently H or optionally substituted C_1-4 alkyl or, in the case of -CO₂R³ and -SO₂R³,

R³ may also be a cation (especially a metal or optionally substituted ammonium cation).

Preferred phthalocyanine groups represented by Pc are each independently selected from metal-free phthalocyanines and metal-containing phthalocyanines. More preferably phthalocyanine groups represented by Pc are each independently selected from copper phthalocyanine and nickel phthalocyanine.

It is preferred that at least one, and preferably both, of the phthalocyanine groups carries a sulpho substituent. It is also preferred that at least one, and preferably both, of the phthalocyanine groups carries a sulphonamide substituent, preferably of the formula SO₂NR⁵R⁶ wherein R⁵ and R⁶ are each independently H, optionally substituted alkyl, optionally substituted aryl or R⁵ and R⁶ together with the N atom to which they are attached form an optionally substituted five or six membered ring. Preferably R⁵ and R⁶ are each independently H or optionally substituted C^-alkyi, especially H or methyl. It is especially preferred that at least one of the phthalocyanine groups carries a sulpho substituent and a sulphonamide substituent of the formula SO₂NR⁵R⁶ wherein R⁵ and R⁶ are as hereinbefore defined.

The optional substituents which may be present on R⁵ and R⁶ are preferably each independently selected from sulpho, carboxy, phosphato, hydroxy and amino. Preferably the compounds described herein are water-soluble.

Compounds of the type as herein described may be prepared by a process comprising condensing at least two molar equivalents of a phthalocyanine compound carrying a group of formula -SO₂Z, wherein Z is a labile group, with a divalent linking group reactive towards -SO₂Z groups. For example diamines of formula HNR¹-L¹-R¹-NH, wherein L¹ and each R¹ independently are as defined above. Alternately the compounds may be prepared by condensing a phthalocyanine compound carrying a substituent of the formula -SO₂NR¹-L¹-NH¹H with a phthalocyanine compound carrying a substituent of the formula -SO₂Z, wherein Z is a labile group and L¹ and R¹ independently are as defined above. Typical labile groups are halogens, especially chloro. According to a second aspect of the present invention there is provided a composition comprising a compound of Formula (1 ) and a liquid medium. Preferred compositions comprise:

(a) from 0.01 to 30 parts of a compound of Formula (1 ); and

(b) from 70 to 99.99 parts of a liquid medium; wherein all parts are by weight and 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 99.9 to 80, more preferably from 99.5 to 85, especially from 99 to 95 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 which 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. Preferred liquid media include water, a mixture of water and an organic solvent and an organic solvent free from water.

When the medium comprises a mixture of water and an 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^-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, pentyiene 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^-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)- ethoxyj-ethanol and ethyleneglycol monoallylether; cyclic amides, preferably 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, caprolactam and 1 ,3-dimethylimidazolidone; cyclic esters, preferably caprolactone; sulphoxides, preferably dimethyl sulphoxide and sulpholane. Preferably the liquid medium comprises water and 2 or more, especially from 2 to 8, water-soluble organic solvents. Especially preferred water-soluble organic solvents are cyclic amides, especially 2- pyrrolidone, N-methyl-pyrrolidone and N-ethyl-pyrrolidone; diols, especially 1 ,5-pentane diol, ethyleneglycol, thiodiglycol, diethyleneglycol and t ethyleneglycol; and mono- C^-alkyl and C_1-4-alkyl ethers of diols, more preferably mono-C^-alkyl ethers of diols having 2 to 12 carbon atoms, especially 2-methoxy-2-ethoxy-2-ethoxyethanol. Although not usually necessary, further colorants may be present in the liquid medium to modify the shade and performance properties of the composition. Examples of such colorants include C.I. Direct Yellow 86, 132, 142 and 173; C.I. Direct Blue 199, and 307; C.I. Food Black 2; C.I. Direct Black 168 and 195; C.I. Acid Yellow 23; and any of the dyes used in ink jet printers sold by Seiko Epson Corporation, Hewlett Packard Company, Canon Inc. & Lexmark International. Addition of such further dyes can increase overall solubility leading to less kogation (nozzle blockage) for the resultant ink.

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 4,251 ,50A. When the liquid medium comprises an 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 dye in the liquid medium. Examples of polar solvents include C^-alcohols. In view of the foregoing preferences it is especially preferred that where the liquid medium is an organic solvent free from water it comprises a ketone (especially methyl ethyl ketone) and/or an alcohol (especially a C_1-4-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 medium is organic solvent free from water it is a mixture of 2 to 5 different organic solvents. This allows a medium to be selected which gives good control over the drying characteristics and storage stability of the ink.

Liquid media comprising an 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.

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

The compositions preferably have a total concentration of divalent and trivalent metal ions other than those associated with the phthalocyanine below 1000, more preferably below 100, especially below 20, more especially below 10 parts per million by weight relative to the total weight of ink. Pure compositions of this type may be prepared by using high purity ingredients and/or by purifying the composition after it has been prepared. Suitable purification techniques are well known, e.g. ultrafiltration, reverse osmosis, ion exchange and combinations thereof. The liquid medium may also contain further components which are 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. The composition may be an ink, especially an ink-jet printing ink, or a liquid dye concentrate which is used to prepare inks. The concentrates are useful as a means for transporting colorant and so minimising costs associated with drying the dye and transporting excess liquid. The compounds of Formula (1 ) have attractive, strong cyan shades and are valuable colorants for ink-jet printing inks. They benefit from a good balance of solubility, storage stability and fastness to water and light. In particular the compounds of Formula (1) are stable to oxidative gases such as ozone, nitrous oxide, NO and NO₂. The compounds of Formula (1 ) particularly benefit from their stability to ozone. A third aspect of the invention provides a process for printing an image on a substrate comprising applying a composition according to the second aspect of the current invention to the substrate by means of an ink jet printer.

The ink jet printer preferably applies the composition to the substrate in the form of droplets which 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 composition in a reservoir by means of a resistor adjacent to the orifice, thereby causing the composition to be ejected 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 composition from the orifice.

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. A fourth aspect of the present invention provides a substrate, especially paper, an overhead projector slide, a textile material, a plastic, glass and metal, printed with a composition, a compound or by means of a process as hereinbefore defined.

A fifth aspect of the present invention provides an ink jet printer cartridge comprising a chamber and a composition wherein the composition is in the chamber and the composition is as described according to the second aspect of the present invention.

A sixth aspect of the invention is a method for the coloration of a substrate which comprises applying thereto a compound according to the first aspect of the invention.

The invention is further illustrated by the following Examples in which all parts and percentages are by weight unless otherwise stated. Example 1 Preparation of:

CuPc NiPc sodium salt

wherein the sum of a + b is 3.

Step 1 : Preparation of:

This compound was prepared by the method described in EP471456A1 , Example 1 first two paragraphs.

Step 2:

The product of step 1 (10.6g) was stirred in water (600ml) at room temperature and pH 9-10. Cl Reactive Blue 25 (11.3g) was added stepwise and the pH maintained at 9-10 using 2M NaOH.

Cl. Reactive Blue 23

The mixture was heated at 70°C for 4hr, cooled and the pH lowered to 7 with concentrated HCI. The precipitated product was filtered, washed with 0.5M HCI, converted to the sodium salt, desalinated and dried to give the product (18.7g) having absorbance maxima at 615 and 660 nm. Analysis by mass spectroscopy revealed multiple species of which the title product was the major component. Example 2 Preparation of:

CuPc sodium salt

Stepl : Preparation of:

Sulphuric acid (9.4g) was added to chlorosulphonic acid (192g) followed by copper phthalocyanine (38.4g) below 60°C. The reaction mixture was heated at 130-140°C for 2hr, cooled and drowned out into ice/water (480g). The precipitated solid was filtered-off and washed with 0.5M HCI (600ml). The solid was added stepwise to a stirred solution of ethylene diamine (4g) in ice/water (340g). The reaction mixture was then heated at 40°C, pH7-8 for 2hr, cooled and the pH was lowered to 3-4 using concentrated HCI. The precipitate was filtered-off and washed with saturated brine to give the compound shown above.

Step 2:

Preparation of:

Copper phthalocyanine (115g) was added in portions to stirred chlorosulphonic acid (317 ml) and concentrated sulphuric acid (147 ml). The mixture was heated to 140°C for 3 hours and then cooled to room temperature. This mixture was then poured onto a stirred mixture of ice (1 kg), water (200 ml), concentrated hydrochloric acid (44 ml) and sodium chloride (40g). The precipitated product was collected by filtration at reduced pressure to obtain a paste of CuPc(SO₃H)₃(SO₂CI)₁ (817.8 g) which was used directly in the next step. Step 3 Preparation of:

The product of step 2 was added to a mixture of p-aminobenzenesulphatoethyl sulphone (133g) in water (700 ml) at pH 5.2 (adjusted by adding 15 % aqueous NaOH). The mixture was stirred at pH 5.2 and room temperature for 3 hours. Sodium chloride (20% w/v) was added to the mixture which was stirred for 15 minutes and the pH of the mixture was adjusted to 1.0 with concentrated hydrochloric acid. The resultant precipitate was collected by filtration at reduced pressure and washed with ice-cold brine (10%) and dried under reduced pressure to obtain 688 g of product.

Step 4: The product of step 1 (23g) was added portion-wise to a stirred solution of the product of step 3 (148 g, 28% strength) in water (1000ml) at pH 9-10 and room temperature. The mixture was heated at 70°C for 4.5 hr at pH 9-10 and then cooled and the pH lowered to pH 3-4 using concentrated HCI. The precipitated solid was filtered-off, washed with 0.5M HCI, converted to the sodium salt, desalinated and dried to give the product (62g) having absorbance maxima at 625 and 665 nm. Analysis by mass spectroscopy revealed multiple species of which the title product was the major component.

Example 3 Preparation of:

The product of Example 1 , Step 1 (20g) was added to a solution of the product of Example 2 Step 3 (92g, 28% strength) in water (1000ml) at pH 9-10. The mixture was heated at 70°C for 4hr, cooled and the pH lowered to 3-4 with concentrated HCI. The precipitate was filtered-off, washed with 0.5M HCI, converted to the sodium salt, desalinated and dried to give the product as a solid (30g) having absorbance maxima at 625 and 660 nm. Analysis by mass spectroscopy revealed multiple species of which the title product was the major component.

Example 4 Preparation of:

sodium salt

Step 1 :

Pre pa ration of:

Copper phthalocyanine (115.2g) was added to chlorosulphonic acid (308ml) below 50°C and then heated at 140°C for 3hr. The mixture was cooled to 40°C and phosphorous trichloride (52g) was added over 1 hr below 50°C. The mixture was then heated at 90°C for 1.5 hr, cooled and poured into ice/water (1400ml). The solid was filtered-off and washed with 0.5M HCI (2000ml). This was added to a stirred solution of chloroethylamine hydrochloride (46.6g) in water (1000ml) at 0°C and the pH was raised to 7-8 with 2M ammonium hydroxide, stirred at 0°C for 1 hr and at 40°C for 0.5 hr. The reaction mixture was cooled, the pH lowered to 1.5 with concentrated HCI and the precipitate was filtered-off and washed with 0.5M HCI. This solid was then stirred in water (2000ml) and concentrated ammonia (500ml) was added. The reaction was then heated at 60-70°C for 4 hr, cooled and the pH adjusted to 4 with concentrated HCI. Precipitated product was filtered-off, washed with water and acetone and dried to give the intermediate (180g) shown above.

Step 2:

The product of Step 1 (18g) was added to the product of Example 2, Step 3 (130g, 28% strength) in aqueous (2000ml) pH 9-10 solution. The reaction mixture was heated at

70°C for 5 hr, cooled and the pH was lowered to 3-4 with concentrated HCI. The resultant precipitate was filtered off, washed with 0.5M HCI, converted to the sodium salt, desalinated and dried to give the product (31 g) having absorbance maxima at 625 and 665 nm. Analysis by mass spectroscopy revealed multiple species of which the title product was the major component.

Example 5 Preparation of:

The compound from Example 2, Step 3 (90g, 28%) was dissolved in water

(1000ml). Ethylene diamine (0.6g) was added and the pH was maintained at 9-10 by the addition of 2M NaOH. The reaction mixture was stirred at room temperature for 1 hr and then at 70°C for 2.5 hr, cooled and the pH lowered to 2-3 with concentrated HCI. The precipitate was collected by filtration, converted to the sodium salt, desalinated and dried to give the product (21.7g) as a solid having absorbance maxima at 630 and 665 nm. Analysis by mass spectroscopy revealed multiple species of which the title product was the major component.

Example 6 Preparation of:

sodium salt

The compound shown in Example 2, Step 2 (90g, 28% strength) was dissolved in water (1000ml). 4,7,10-trioxatridecadiamine (2.2g) was added and the pH was maintained at 9-10 by the addition of 2M NaOH. The reaction mixture was stirred at room temperature for 1 hr and then at 70°C for 2.5 hr, cooled and pH lowered to 2-3 with concentrated HCI. The precipitate was filtered-off, converted to the sodium salt, desalinated and dried to give the product (23g) as a solid having absorbance maxima at 630 and 665 nm. Analysis by mass spectroscopy revealed multiple species of which the title product was the major component.

Example 7

Preparation of inks Inks were prepared by dissolving 3 parts (weight by weight) of the dye in a stock solution of 5 parts 2-pyrrolidone, 5 parts thiodiglycol, 2 parts Surfynol 465 (a surfactant commercially available from Air Products Inc.) and 85 parts distilled water with the addition of concentrated sodium hydroxide to give a pH of 8.5 to 9. The resultant inks were as follows:

Ink (1) contained Dye (1 )

Ink (2) contained Dye (2)

Ink (3) contained Dye (3)

Ink (4) contained Dye (4) Ink (5) contained Dye (5)

Ink (6) contained Dye (6)

Comparative Ink contained Comparative Dye

The Comparative Dye was C.I. Direct Blue 199, a copper phthalocyanine dye obtained from Avecia Limited.

Each ink was filtered through a 0.45μm filter and put into one chamber of a Canon trichamber inkjet cartridge.

"Surfynol" is a registered trade mark of Air Products Inc.

Ink Jet Printing

Inks 1 and 2 were then ink jet printed onto each of the substrates shown in Tables A to F using a Canon 4300 U printer, the following results were obtained:

The CIE colour co-ordinates of each print (a, b, L, Chroma) were measured using a Xrite 983 Spectrodensitometer with 0°/45° measuring geometry with a spectral range of 400-700nm at 20nm spectral intervals, using illuminant C with a 2° (CIE 1931 ) observer angle and a density operation of status T. No less than 4 measurements were taken diagonally across a solid colour block on the print with a size greater than 10mm x 10mm.

The OD is the optical density of the printed paper, as measured by a Xrite 983 Spectrodensitometer Table A: Ink 1

Table E: Ink 5

Further Inks

The inks described in Tables I and II may be prepared wherein the Dye described in the first column is the Dye made in the above example of the same number. Numbers quoted in the second column onwards refer to the number of parts of the relevant ingredient and all parts are by weight. The inks may be applied to paper by thermal or piezo ink jet printing.

The following abbreviations are used in Table I and II:

PG = propylene glycol

DEG = diethylene glycol NMP = N-methyl pyrollidone

DMK = dimethylketone

I PA = isopropanol

MEOH = methanol

2P = 2-pyrollidone 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

Claims

1. A compound of Formula (1 ):

Pc -SO₂-L-SO₂-Pc

Formula (1 ) wherein: each Pc is independently an optionally substituted phthalocyanine group; and L is a divalent linking group; provided that:

2. A compound according to claim 1 wherein L is a group of Formula (2):

-NR¹-L¹-NR¹-

Formula (2)

wherein:

R¹ is H, optionally substituted alkyl or optionally substituted aryl; and L¹ is a divalent linking group comprising from 1 to 30 carbon atoms and 0 to 20 atoms selected from oxygen nitrogen and sulphur. provided that:

3. A compound according to claim 1 and claim 2 wherein L¹ is of Formula (3):

-G-X(C_nH_2n - X)_p-G-

Formula (3)

wherein: each G independently is optionally substituted alkylene or arylene; each X independently is an ester, amide, amine, sulphone, sulphoxide, ether or thioether; n is from 1 to 6; and p has a value of from 0 to 10. provided that:

4. A compound according to any one of the preceding claims wherein the phthalocyanine groups are each independently selected from metal-free phthalocyanines and metal containing phthalocyanines.

5. A compound according to any one of the preceding claims wherein the phthalocyanine groups are each independently selected from copper phthalocyanine and nickel phthalocyanine.

6. A compound according to any one of the preceding claims wherein at least one of the phthalocyanine groups carries a sulpho substituent.

7. A compound according to any one of the preceding claims wherein at least one of the phthalocyanine groups carries a sulphonamide substituent.

8. A compound according to any one of the preceding claims wherein at least one of the phthalocyanine groups carries a sulpho substituent and a sulphonamide substituent of the formula SO₂NR⁵R⁶ wherein R⁵ and R⁶ are each independently H, optionally substituted alkyl, optionally substituted aryl or R⁵ and R⁶ together with the N atom to which they are attached form an optionally substituted five or six membered ring.

9. A compound according to any one of the preceding claims which is water-soluble.

10. A process for preparing a compound according to any one of the preceding claims comprising condensing two molar equivalents of a phthalocyanine compound carrying a group of formula -SO₂Z with a diamine of formula HNR¹-L¹-R¹-NH wherein Z is a labile group and L¹ and each R¹ independently are as defined in claim 2.

11. A process for preparing a compound according to any one of claims 1 to 9 wherein a phthalocyanine compound carrying a substituent of the formula -SO₂NR¹-L¹-NH¹H is condensed with a phthalocyanine compounds carrying a substituent of the formula -SO₂Z, wherein Z is a labile group and L¹ and R¹ independently are as defined in claim 2.

12. A composition comprising a compound according to any one of claims 1 to 9 and a liquid medium.

13. A composition according to claim 12 which is an ink or liquid dye concentrate.

14. A process for printing an image on a substrate comprising applying a composition according to claim 12 to the substrate by means of an ink jet printer.

15. A paper, an overhead projector slide, a textile material, a plastic, glass and metal printed with a composition according to claim 12, with a compound according to any one of claims 1 to 9 or by means of a process according to claim 14.

16. An ink-jet printer cartridge comprising a chamber and a composition wherein the composition is in the chamber and the composition is as described in claim 12.

17. A method for the coloration of a substrate which comprises applying thereto a compound according to any one of claims 1 to 9.