INK
Description of the Invention This invention relates to inks and their use in inkjet printing ("IJP"). IJP is a non-impact printing technique in which ink droplets are ejected through a thin nozzle onto a substrate without bringing the nozzle into contact with the substrate. There are many demanding performance requirements for the inks used in IJP. For example, they desirably provide images without halos, sharp, which have good firmness in wet conditions, good firmness against light and good optical density. Inks are often required to dry quickly when applied to a substrate to prevent staining, but they should not form a coating on the tip of a nozzle for inkjet because this will stop the printer from working . The inks must also be stable in storage during the course of time without decomposition or formation of a precipitate which could block the fine nozzle. O 01/48090 refers to azo compounds of the metal chelate comprising a component of naphthol and certain heterocyclic groups. WO 01/48090 does not describe such
Ref. 160739 compounds further substituted by a triazole ring for use in ink formulations. According to a first aspect of the present invention there is provided an ink comprising: (a) A metal chelate compound of the Formula
(1) or a salt thereof, where it is nickel;
Formula (1) and (b) a liquid medium. It is especially preferred that the inks comprising the compound of Formula (1) are magenta. The inks comprising the compound of
Formula (1) provide impressions exhibiting high firmness against light, good firmness against oxidative gases such as ozone and good optical density, particularly when used for ink jet printing. The inks according to the present invention are also highly soluble which improves the operational capacity and reduces the formation of layers and blocking of the nozzle when the inks containing the compounds are used in an ink jet printer. It is especially preferred that the compound of
Formula (1) is in the form of a sodium, lithium, potassium, ammonium or substituted ammonium salt, because it has been found that these salts provide prints that exhibit a high firmness against light when incorporated in an ink to inkjet printing. The metal chelate compound of the Formula (1) or a salt thereof according to the present invention and the inks comprising the compound of the Formula (1) also include the tautomers thereof, especially the tautomers of the triazole ring. The compound of Formula (1) can be converted to a salt using known techniques. For example, an alkali metal salt of a compound can be converted to a salt with ammonia or an amine by dissolving an alkali metal salt of the dye in water and passing the solution through a column of a properly modified ion exchange resin. . The inks according to the present invention can be, and preferably are, purified to remove undesirable impurities before they are incorporated into the inks for ink jet printing. Conventional techniques can be used for purification, for example ultrafiltration, reverse osmosis and / or dialysis. The liquid medium preferably comprises: (i) water; (ii) a mixture of water and an organic solvent; or (iii) a water-free organic solvent. The number of parts by weight of component (a) of the ink is preferably from 0.01 to 30, more preferably from 0.1 to 20, especially from 0.5 to 15, and more especially from 1 to 5 parts. The number of parts by weight of component (b) is preferably from 99.99 to 70, more preferably from 99.9 to 80, especially from 99.5 to 85, and more especially from 99 to 95 parts. The number of parts of (a) + (b) is 100 and all the parts mentioned here are by weight. 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 concentrates that can be used to prepare more dilute inks and reduces the probability of precipitation of the compound (s) of the component (a) of the ink if evaporation of the liquid medium occurs during storage.
When the liquid medium comprises a mixture of water and an organic solvent, the weight ratio of the water to the 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 be a water miscible organic solvent or a mixture of such solvents. Preferred water-miscible organic solvents include Ca_6 alkanols; preferably methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, n-pentanol, cyclopentanol and cyclohexanol; linear amides, preferably dimethylforde or dimethylacetamide; ketones and ketone alcohols, preferably acetone, methyl ether ketone, cyclohexanone and diacetone alcohol; ethers miscible in water, 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-alkylene glycols, preferably diethylene glycol, triethylene glycol, polyethylene glycol and polypropylene glycol; triols, preferably glycerol and 1,2, S-hexanetriol; mono-Ci_-ethers of diols, preferably mono-Ci-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-ethoxyethoxy) 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 sulfolane. Preferably the liquid medium comprises water and 2 or more, especially from 2 to 8, organic solvents miscible in water. 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, ethylene glycol, thiodiglycol, diethylene glycol and triethylene glycol; and monoCi-alkyl and Ci_4-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. When the liquid medium comprises a water-free organic solvent, (ie less than 1% water by weight) the solvent preferably has a boiling point from 30 ° to 200 ° C, more preferably from 40 ° to 150 ° C, especially from 50 to 125 ° C. The organic solvent may be non-miscible in water, miscible in water or a mixture of such solvents. Preferred water miscible organic solvents are any of the water-miscible organic solvents described hereinbefore and mixtures thereof. Preferred non-miscible solvents in water include, for example, aliphatic hydrocarbons; esters, preferably ethyl acetate; chlorinated hydrocarbons, preferably C 2 Cl 2 and ethers, preferably diethyl ether; and mixtures thereof. When the liquid medium comprises an organic solvent immiscible with water, preferably a polar solvent is included because it improves the solubility of the metal chelate compound in the liquid medium. Examples of the polar solvents include C1-4 alcohols. In view of the above preferences it is especially preferred that wherein the liquid medium is a water-free organic solvent, it comprises a ketone (especially methyl ethyl ketone) and / or an alcohol (especially a C 1-4 alkanol, such as ethanol or propanol). The water-free organic solvent can be a single organic solvent or a mixture of two or more organic solvents. It is preferred that when the medium is a water-free organic solvent, it is a mixture of 2 to 5 different organic solvents. This allows a medium to be selected which provides good control over the drying characteristics and the storage stability of the ink.
The ink medium comprising a water-free organic solvent is particularly useful where fast drying times are required and particularly when printing on hydrophobic and non-absorbent substrates, for example plastics, metals and glass. A preferred ink especially comprises: (i) 1 to 10 parts in total of the compound of the Formula (1) or a salt thereof; (ii) 2 to 60, more preferably 5 to 40 parts of water soluble organic solvent; and (iii) 30 to 97, more preferably 40 to 85 parts of water; wherein all the parts are by weight and the sum of the parts (i) + (ii) + (iii) = 100. When the liquid medium in the ink comprises a mixture of water and an organic solvent; or a water-free organic solvent, component (i) of the ink may comprise a compound of Formula (1) or a salt thereof, as defined herein above. The preferred low melting point solid medium has a melting point in the range from 60 ° C to 125 ° C. Suitable low melting solids include long chain fatty acids or alcohols, preferably those with chains of C18-2A, and sulfonamides. A compound of Formula (1) can be dissolved in the low melting point solid or can be finely dispersed therein. The inks according to the present invention may also contain additional components conventionally used in inks for ink-jet printing, for example viscosity and surface tension modifiers, corrosion inhibitors, biocides, additives for the reduction of the formation of a cake, anti-wrinkle agents to reduce curling of the paper and surfactants which can be ionic or non-ionic. The pH of the ink is preferably from 4 to 11, more preferably from 7 to 10. The viscosity of the ink at 25 ° C is preferably less than 50 cP, more preferably less than 20 cP and especially less than 5 cP. A second aspect of the present invention provides a process for printing an image onto a substrate comprising the application thereto by means of an ink jet printer, of an ink according to the first aspect of the present invention. The preferences for the ink used in this process are defined as hereinabove with respect to the first aspect of the present invention. The ink jet printer preferably applies the ink to the substrate in the form of droplets which are ejected through a small hole on the substrate. Preferred ink jet printers are ink jet printers, piezoelectric printers, and thermal ink jet printers. In thermal inkjet printers, programmed heat pulses are applied to the ink in a reservoir by means of a resistor adjacent to the orifice, thereby causing the ink to be ejected in the form of small droplets directed towards the ink. the substrate during the relative movement between the substrate and the hole. In piezoelectric ink jet printers, the oscillation of a small crystal causes ejection of the ink from the hole. 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 common or treated papers which may have an acid, alkaline or neutral character. Examples of commercially available papers include, HP Premium Coated Paper, HP Photo Paper (all available from Hewlett Packard Inc.), Stylus Pro 720 dpi Coated Paper, Epson Photo Quality Shiny Film, Epson Photo Quality Shiny Paper (available from Seiko Epson Corp.), High Resolution Paper Canon HR 101, Glossy Paper Canon GP 201, High Brightness Film Canon HG 101 (all available from Canon Inc.), Wiggins Conqueror Paper (available from Wiggins Teape Ltd), Xerox Acid Paper and Xerox Alkaline Paper, Xerox Acid Paper (available from Xerox). A third aspect of the present invention provides a substrate, preferably a paper, an overhead projector slide or a textile material, printed with an ink according to the first aspect of the present invention or by means of the process according to the second aspect of the present invention. According to a fourth aspect of the present invention there is provided an ink jet printer cartridge comprising a chamber and an ink, wherein the ink is present in the chamber and is as defined in the first aspect of the present invention. . According to a fifth aspect of the present invention there is provided an ink jet printer containing an ink jet printer cartridge, wherein the ink jet printer cartridge is as defined in the fourth aspect of the invention. present invention. The invention is further illustrated by the following Examples in which all parts and percentages are by weight unless otherwise specified.
Example 1 Compound (1) wherein M is nickel
Compound (1)
Step (a): Preparation of 2-acetoxynaphthalene-3,6-disulfonic acid
Acetic anhydride (350 ml, 3.8 mol) was added dropwise to a suspension of disodium salt of 2-hydroxynaphthalene-3,6-disulfonic acid (87 g, 0.25 mol) in N, N-dimethylacetamide (350 ml). The reaction mixture is stirred at 125 ° C for 24 hours, cooled to room temperature and added to the acetone (2500 ml). The product was removed by filtration, washed with acetone (3 x 100 mL) and dried to give 95.2 g of a cream colored solid. Step (b): Preparation of 3,6-bis- (4-carboxy-phenylsulfamoyl) -2-hydroxynaphthalene
POCI3 (50 ml, 0.538 mol) is added dropwise to a suspension of the product of step (a) (50 g, 0.128 mol) in acetonitrile (250 ml) at reflux. The reaction mixture is stirred for 3 hours at 70 ° C, cooled, added to ice / water (4000 ml) and the naphthalene disulfonyl chloride is extracted with dichloromethane (4 x 300 ml). The combined extracts are dried with gSO4, evaporated under reduced pressure and the residue is dissolved in N, -dimethylacetamide (400 ml). 4-Aminobenzoic acid (34.3 g, 0.25 mol) is added to the above solution, the reaction mixture is stirred overnight at room temperature and then added to the water (3000 ml). The pH is then reduced to 0.5 with concentrated H2SO4 and the precipitated product is extracted from ethyl acetate (4 x 300 mL). The combined extracts were washed with 1N HC1 (600 mL), dried with gSC > 4 and evaporate under reduced pressure. The residue is dissolved in water (1000 ml) at pH 12 (2N NaOH) and then stirred for 1 hour at 50-60 ° C. The solution is allowed to cool, the pH is reduced to pH 4 with concentrated HCl and the product is removed by filtration and dried to give 41.5 g (53% yield) of a tan solid. Step (c): 3-amino-1,2,4-triazolo-5-carboxylic acid hydrate (1.28 g, 0.01 mol) was suspended in water (50 ml) and dissolved by the addition of 2M NaOH to pH 8. The sodium nitrite (0.76 g, 0.011 mol) was added and the solution stirred until the sodium nitrite had dissolved. The mixture was then added dropwise to a cooled mixture of ice-water (30 g) and concentrated HCl (3.0 ml) at 0-5 ° C, the mixture was stirred for 30 minutes, at 0-5 ° C and then remove excess nitrous acid by the addition of sulfamic acid. The diazo suspension was slowly added to a solution of the product from step (b) (5.42 g, 0.01 mol) in water (100 ml) at pH 7-8 (2N NaOH) cooled down to 5 ° C. The reaction mixture was then stirred at 0-5 ° C for an additional hour, the product was precipitated by acidification to pH 4 with 2N HCl and collected by filtration. The product is then washed with water and dried in a vacuum desiccator to give 6.4 g of an orange solid. Step (d): Preparation of Compound (1) A solution of tetrahydrate and nickel acetate (1.38 g, 0.0055 mol) in water (10 ml) is added dropwise to the product of step (c) (5.0 g, 0.0073 mol ) dissolved in water (100 ml) at pH 7 (2N NaOH). The reaction mixture is stirred for 2 hours at room temperature, dialyzed using a SpectraPor membrane pipe (cut-off molecular weight of 3500) to a low conductivity (<100μ?). The product was obtained by evaporation under reduced pressure to give a dark crystalline solid (6 g). The analysis by mass spectrometry found was m / z 1419. Required M + = 1420. Example 2 - Inks The inks described in Tables I and II can be prepared wherein the Compound described in the first column is the Compound made in the Example 1. The numbers cited in the second column, progressive, refer to the number of parts of the relevant ingredient and all parts are by weight. Inks can be applied to paper by ink jet printing, in thermal or piezoelectric printers. The following abbreviations are used in Tables I and II: PG = propylene glycol DEG = diethylene glycol NMP = N-methyl pyrrolidone DMK = dimethyl ketone IPA = isopropanol MEOH = 2P methanol = 2-pyrrolidone MIBK = methyl isobutyl ketone P12 = propane-1, 2- diol BDL = butane-2, 3-diol CET = cetyl ammonium bromide PHO = Na2HP0 and TBT = tertiary butanol TDG = thiodiglycol TABLE I ComConteniAgua PG DEG NMP DMK NaOH Estea- IPA MEOH 2P M1BK put from time Na dye 2.0 80 5 6 4 5 1 3.0 90 5 5 0.2 1 10.0 85 3 3 3 5 1 1 2.1 91 8 1
1 3.1 86 5 0.2 4 5
1 1.1 81 9 0.5 0.5 9 1 2.5 60 4 15 3 3 6 10 5 4
1 5 65 20 10 1 2.4 75 5 4 5 6 5
1 4.1 80 3 5 2 10 0.3 1 3.2 65 5 4 6 5 4 6 5
1 5.1 96 4 1 10.8 90 5 5 1 10.0 80 2 6 2 5 1 4 1 1.8 80 5 15
1 2.6 84 11 5
TABLE I (Cont.)
TABLE II
It is noted that in relation to this date the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.