GB2311075A - Ester or amide containing xanthene dyes for use in ink jet or hot melt inks - Google Patents

Abstract

A compound of Formula (1): wherein: X 1 is an ester group or an amide group (eg of a carboxylic or sulphonic acid) or a fatty amine salt of a sulphonic acid; each X 2 independently is a substituent; m has a value of from 0 to 2; Y 1 and Y 2 are each independently H, alkyl or halo; each Z independently is an ester or amide group; and A - is an anion. The compound is useful as a colorant for toners, D2T2 printing, plastics, polyesters, nylons and inks, especially inkjet or hot melt inks.

Description

CHEMICAL COMPOUNDS This invention relates to xanthene compounds having ester or amide groups and to processes for their preparation and use. The compounds may be used as coloured toners in photocopiers, in D2T2 printing or as a colorant for plastics, polyesters, nylons or inks, particularly inks used in phase change ink jet printing.

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

wherein: xl is an ester or amide group or a fatty amine salt of a sulphonic acid; each X2 independently is a substituent; m has a value of from 0 to 2; yl and y2 are each independently H, alkyl or halo; each Z independently is an ester or amide group; and A- is an anion.

It is preferred that xl is an ester or amide group, especially an ester group.

A preferred ester group is of the formula -C02R1 or -S020R1 wherein R1 is optionally substituted phenyl or optionally substituted C1-20-alkyl, especially a phenyl or Cl,q-alkyl group substituted by O to 3 groups selected from halo, especially chloro or bromo; alkyl, especially C1-4-alkyl; and alkoxy, especially C4-alkoxy.

Examples of preferred ester groups include -C02(CH2)3CH3, C02(CH2)2CH3, CO2Cli2CH3, C02CH2CH20CH2CH3, C02CH2CH20(CH2)3CH3, C02CH(CH3)CH2CH3 and C02(CH2)5CH3.

A preferred amide group is of the formula -C02NR2R3 or -S02NR2R3 wherein R2 and R3 are each independently H or C1,20-alkyl, more preferably C2,10-alkyl. Preferably R2 is H and R3 is Cl~20-alkyl.

Preferred fatty amine salts of a sulphonic acid are of the formula -S03-M+ wherein M+ is a quaternary amine containing at least 8 carbon atoms. M+ is preferably of formula +NQ4 wherein each Q independently is H or alkyl, provided that M+ contains at least 8 carbon atoms, preferably from 8 to 18 carbon atoms. It is preferred that three Qs are H and one Q contains from 8 to 18 carbon atoms.

An especially preferred fatty amine salt is derived from tertiary alkyl primary amine, for example as described in US patent 5,084,099 column 4, line 24 to column 5, line 48, which is incorporated herein by reference thereto.

The nature and position of the substituent or substituents defined by -(X2)m is generally selected on the basis of synthetic convenience. It is preferred that each X2 independently contains less than 7 carbon atoms. As examples of substituents represented by X2 there may be mentioned halo, especially chloro; an amide group; alkyl, especially C14-alkyl; alkoxy, especially C1,4-alkoxy; and an ester group. It is preferred that m has a value of 1, more preferably 0.

As will be appreciated the compound of Formula (1) can exist in tautomeric forms other than that illustrated and these are intended to be included in the definition provided by Formula (1).

When yl or Y2 is an alkyl group it preferably has less than seven carbon atoms, and more preferably is Cl~4-alkyl, especially methyl. When yl or Y2'is halo it is preferably chloro. It is preferred that yl and Y2 are identical to each other.

It is preferred that one or both of the groups represented by Z are at the 5-position indicated in Formula (1). Preferably the groups represented by Z are identical to each other and, in one embodiement, are identical to the group represented by X1.

The anion represented by A- is preferably a colourless anion.

Examples of colourless anions include a carbonate, bicarbonate, sulphate, nitrate, bisulphate, acetate, benzoate, halide or phosphate, especially chloride, bromide and sulphate.

The compounds of Formula (1) may be prepared by condensing together compounds of Formula (2), (3) and (4) wherein X2, m, yl and y2 are as hereinbefore defined, zl is an acid group, preferably a sulpho or carboxy group, and X3 is C=O or SO2, followed by esterification or amidification of the acid groups Z1 to give a compound of Formula (1):

Condensation of compounds (2), (3) and (4) is preferably performed at a high temperature, more preferably above l500C, especially in the range 170-1900C. The condensation may be performed in a high boiling solvent, for example sulpholane.

Esterification of the acid groups may be achieved by heating with an alcohol and mineral acid or by converting them to an acid chloride and reacting with an alcohol. It will be apparent to those skilled in the art how acid groups can be converted to an acid chloride, for example carboxy groups may be heated with thionyl chloride and sulpho groups may be heated with chlorosulphonic acid. Methods of converting acid groups to amides (ie, amidification) will also be apparent to those skilled in the art, for example by converting an acid to an acid chloride and reacting an acid chloride with the amine.

Compounds containing both ester and amide groups may be prepared by performing the above described condensation using a compound of formula (2) or (3) where Z1 is an ester or amide group and subsequently converting any acid group present, for example a carboxy or sulpho group derived from X3, to an amide or ester group as desired.

When X3 is S02 a compound of Formula (3) may be condensed in a step-wise manner with a compound of Formula (2) under mild conditions, followed by condensation with a compound of Formula (4) under more forcing conditions. This is of particular value where the compounds of Formula (2) and (4) are different to each other.

The compound of Formula (1) may be used in coloured toners, D2T2 printing, coloured plastics, as a disperse dye for cotton or nylon or as an ink colorant.

The compounds of Formula (1) are especially useful for the preparation of inks, especially phase change inks, used in ink jet printing. The inks can be prepared according to formulations analogous to those known in the art, for example those described in US patents 5,084,099, 4,390,369 or European Patent 0181198. The preferred inks contain up to 102, or preferably l-5Z (by weight), of a compound of Formula (1) and a vehicle having a melting point in the range 30"C to 1300C. Preferred vehicles having a melting point in the range 30"C to 1300C comprise a paraffin, fatty acid, fatty alcohol or fatty ester or a wax or mixture thereof.

The ink preferably has a maximum viscosity of 50 centipoises, more preferably less than 20 centipoises, especially less than 14 centipoises when molten.

In addition to the above-described components, the ink of the present invention may contain a ketone, preferably having a melting point in the range of 65 to 1200C, for example a stearone or laurone.

The ketone preferably does not exceed 50Z by weight of said ink. The present inks may optionally also contain up to 4Z by weight of a plasticizer, such as an acrylic resin plasticizer, for example as described in European Patent Application 85.305977.2.

The preferred paraffin is a chlorinated paraffin having a chlorine content of 65X to 72Z by weight, obtained by chlorinating a paraffin or mixture of paraffins containing from 18 to 35 carbon atoms.

Especially preferred paraffins are described in EP 333,335 A2, column 2 lines 17 to 43 which are incorporated herein by reference thereto.

The preferred fatty acid, fatty alcohol or fatty ester vehicle contains from 18 to 26 carbon atoms, especially preferred are C1824 alcohols. Stearic acid or behenic acids are suitable fatty acids, behenic presently being preferred over stearic.

The preferred vehicle is a wax, particularly candelilla wax, having a melting point above 65 CC. Other waxes believed suitable include bamboo leaf, bees waxes, caranda, carnauba, hydrogenated castor oil, Chinese insect, cotton, cranberry, certain Douglas-fir bark, asparto, certain flax, Indian corn, Madagascar, most micro-crystalline waxes, montan, ouricury, ozocerite, palm, peat wax, rice bran, shellac wax, sisal hemp, sorghum grain, Spanish moss, refined sugar cane waxes and mixtures thereof, each of which waxes has a melting temperature above about 650C. Mixtures of such waxes found suitable for jetting include 50-50 mixture of candelilla and carnauba wax.

In addition to providing an ink, the present invention also provides a method of ink jet printing comprising the steps of (a) heating an ink as hereinbefore described to a temperature above its melting point, preferably above 80"C, and (b) impulse jetting said ink onto a substrate whereupon said ink solidifies to form a print.

Suitable methods of impulse jetting an ink as hereinbefore described will be apparent to those skilled in the art, for example using a commercially available phase change ink jet printer.

The compound of Formula (1) has an attractive bright magenta shade, high tinctorial'strength and excellent water fastness when printed on plain paper or an overhead projector sheet.

The invention is further illustrated by the following Examples in which all parts and percentages are by weight unless otherwise indicated.

Example 1 Preparation of the compound of Formula (5) where X is n-butoxycarbonyl and Q1 and Q2 are both 2-methyl-5-n-butoxycarbonylphenyl

Stage a) - Condensation A mixture of 3,6-dichlorofluoran (7.4g), 3-amino-4methylbenzoic acid (9.lg), zinc chloride (4.2g) and sulpholane (20g) was stirred at 1800C for 3 hours. After cooling, the mixture was added to icelwater (200g) and concentrated hydrochloric acid (10 ml) was added.

The resultant precipitate was filtered off and washed with water.

The precipitate was added to water (600ml) and the pH adjusted to 9.0-9.5 by addition of sodium hydroxide solution. The solution was screened and the filtrate acidified to pH 3 with concentrated hydrochloric acid. The carboxy dye in the free acid form was filtered off, washed with a little water to give a solid and then dried.

Stave b) - Esterification To log of the product of stage a) in n-Butanol (300ml) was added concentrated sulphuric acid SG 1.84 (3ml) and the mixture stirred under reflux for 4 hours. After cooling to room temperature the solution was poured onto water (1 litre). The organic layer was separated from the aqueous layer and dried over Magnesium Sulphate. The dry solution was screened and n-butanol evaporated off leaving an oil.

The oil was dissolved in toluene (100ml) and screened. The toluene was evaporated off, hexane added and the title product (~SO42- salt) precipitated from the oil as a solid. The product was filtered off and dried, and was found to have a lambda max at 545nm in toluene.

Example 2 The method of Example 1, Stage a), was repeated and 10g of the product of Stage a) was added to toluene (200ml). One drop of dimethyl formamide was added, followed by dropwise addition of thionyl chloride (8.3g) and the mixture stirred and heated under reflux for 1 hour.

Approximately lOml of the reaction mixture was allowed to distill off to remove excess thionyl chloride. The mixture was cooled to 400C and 20g of n-butanol added dropwise. The mixture was stirred under reflux for 1 hour and cooled. Further toluene (200ml) was added followed by water (600ml) and the pH adjusted to 9-10 by addition of 2N sodium hydroxide solution.

The resultant organic layer was separated off, washed with water (lOOml) and dried over magnesium sulphate. The solvent was then evaporated off and the solid residue dried at 5O0C, to give the title product (chloride salt).

A solid phase change ink may be prepared by adding C.75g of the title dye to a vehicle prepared by mixing Kemamide S-180 (56g, Witco Corporation), Unirez X37-523-235 (a dimer acid based tetra-amide material manufactured by Union Corporation, formed by the reaction of one mole of dimer acid, two moles of ethylenediamine and two moles of stearic acid), Arakawa KE-311 resin (lOg) and Naugard 524 (0.lg) at 1100C to give a homogenous solution, and removing any solids by filtration. The ink so prepared may be used to print paper using a conventional phase change ink jet printer.

Claims (9)

1. A compound of Formula (1):

wherein: xl is an ester or amide group or a fatty amine salt of a sulphonic acid; each X2 independently is a substituent; m has a value of from 0 to 2; yl and Y2 are each independently H, alkyl or halo; each Z independently is an ester or amide group; and A- is an anion.

2. A compound according to Claim 1 wherein X1 is an ester group.

3. A compound according to Claim 2 wherein X1 is an ester group of the formula -C02R1 or -S020R1 wherein R1 is optionally substituted phenyl or optionally substituted Cl~20-alkyl.

4. A compound according to any one of the preceding claims wherein X2 contains less than 7 carbon atoms.

5. An ink comprising upto 101 of a compound according to any one of Claims 1 to 4 and a vehicle having a melting point in the range 30"C to 1300C.

6. An ink according to Claim 5 having a viscosity of up to 50 centipoises when molten.

7. A method of ink jet printing comprising the steps of (a) heating an ink according to Claim 5 or 6 above its melting point and (b) impulse jetting the ink onto a substrate whereupon the ink solidifies to form a print.

8. A substrate printed by a method according to Claim 7.

9. Use of a compound defined in Claim 1 as a colorant in a hot melt ink jet printing ink.