KR100420028B1 - Black Dye for Inkjet Inks - Google Patents

Abstract

As a dye for inkjet ink, which solves the problems of the conventional water-soluble black dye and exhibits excellent printing quality while retaining moisture and light durability, through the azo bond of naphthalene derivatives, the following Chemical Formula 1 is a basic skeleton structure and three naphthalenes It is a novel compound with derivatives.

[Formula 1]

Wherein W is hydrogen or a carboxyl group and X, Y and Z represent hydrogen or sulfonic acid groups the same or differently.

Description

Black Dye for Inkjet Inks

[Industrial use]

The present invention relates to ink jet inks, and more particularly, to a novel black dye useful as a dye for ink jet inks having a basic skeleton structure of formula (1) and a method for producing the same.

[Formula 1]

Wherein W is hydrogen or carboxyl group (COOH) and X, Y and Z represent hydrogen or sulfonic acid group (SO ₃ H).

[Prior art]

In general, inkjet inks using water-soluble pigments in which water is used as the main solvent have been employed in inkjet printers. The general basic requirements for such inkjet inks are summarized as follows.

First, after ink is jetted by a bubble jet or thermal jet or Piezo-electric jet, it must have basic physical properties as ink to form a constant image. These properties include surface tension, Viscosity and electrical conductivity. In the case of having such basic physical properties, it is possible not only to output a clear image as ink, but also to solve a problem caused by jetting.

Second, the storage stability of the ink should be excellent. In other words, when ink is used as a cartridge or a rechargeable battery, the pigment or composition does not precipitate or float even if it is stored for a long time in the storage container. By doing so, it is necessary to fundamentally solve the clogging of the nozzle and to continuously output a clear image.

Third, a clear image must be formed after the ink is jetted. In other words, the intensity of the color should be high and there should be no bleeding, and the image after printing should be clear because it has the proper penetration speed in the proper medium such as paper or film. In order to have such an image, it can be said that selection of a pigment is important above all.

Fourth, the fastness of the image should be excellent. In general, durability means fastness due to light or water, which is the most important requirement for maintaining the color as the primary color even after long time storage after printing. Depending on the durability may vary.

On the other hand, the water-soluble black dye is a C.I. Numerous textile dyes have been developed since Direct Black 51 (Color Index, 3rd ed., Vol. 4, No. 27720, p4251) was developed by K. Krekeler et al. CI of Formula 3 as disclosed in US Pat. No. 4,761,180 and USP 4,767,459 and USP 5,026,425, etc. Food Black 2 (Color Index, 3rd ed., Vol. 4, No. 27755, p4251) and C.I. Direct Black 168.

[Formula 2]

[Formula 3]

[Formula 4]

However, when the ink is used using such a dye, the color density and the color direction are relatively satisfactory, but as shown in the molecular structure, the sulfonic acid group, which is a water-soluble group, has a lot of water durability after forming the image after jetting. Have

Numerous efforts have been made to supplement and improve the moisture durability. In US Pat. No. 5,053,495, a method of improving moisture durability by selecting a ratio of carboxyl and sulfonic acid groups in a constant state was selected. Although this method has been somewhat successful in improving moisture durability, there are problems in nozzle clogging due to solubility limitations and storage stability due to problems of color density and storage stability.

Another approach to improve moisture durability is to choose a method of increasing the structure of the molecule to increase the color fastness to the water, such as US Patent Nos. 5,127,946 and USP 5,127,947. Such pigments are generally used instead of monoazo or disazo. Tris azo having three azo groups in the skeletal structure has been published. However, the pigments presented here have problems of difficulty in controlling the proper ratio of sulfonic acid groups or carboxyl groups having water-soluble groups and water solubility and permeability after jetting, which may cause problems in storage stability and print quality. Have.

The basic skeleton is a pigment having a naphthalene derivative and a naphthalene derivative as an azo bond, and is disclosed in US Pat. No. 5,254,160, but this is a monoazo derivative having a single azo bond. The problem that the light durability which is the biggest drawback of monoazo is pointed out is pointed out.

The present invention has been made to solve the above problems of the prior art, an object of the present invention is to provide a novel pigment for ink that can exhibit excellent print quality while retaining moisture and light durability and a method for producing the same.

[Means for solving the problem]

The present invention has the following configuration to achieve the above object of the present invention.

In the present invention, a free dye form provides a black dye for inkjet ink represented by the following formula (1).

[Formula 1]

Wherein W is hydrogen or a carboxyl group and X, Y and Z represent hydrogen or sulfonic acid groups the same or differently.

The present invention is preferably in the form of an alkali metal salt or ammonium salt or organic ammonium salt by neutralizing the carboxyl group and sulfonic acid group of the formula (1).

In addition, in the present invention, the black dye is preferably selected from the group consisting of compounds having Formula 7, Formula 8, Formula 9, Formula 10, and Formula 11.

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

[Formula 11]

Also, in the present invention, the inkjet ink comprising the step of synthesizing the compound of formula 1 by the diazotization reaction of the compound of formula 5 and the compound of formula 5 subjected to the diazotization reaction with the compound of formula 6 It provides a method for producing a black dye.

[Formula 5]

[Formula 6]

Wherein W is hydrogen or a carboxyl group and X, Y and Z represent hydrogen or sulfonic acid groups the same or differently.

The present invention also provides an inkjet ink composition comprising a black dye for inkjet ink, an alkali metal salt or an ammonium salt or an organic ammonium salt obtained by neutralizing the carboxylic acid and sulfonic acid groups of the formula (1) in free acid form, and a solvent and a surfactant. .

Preferably, the black dye for inkjet ink is 0.1 wt% to 10 wt%, and the solvent is water or a mixed solution of water and a water-soluble organic solvent, and the water-soluble organic solvent has an alcohol having 1 to 4 carbon atoms and a hydroxy group of 2 It is preferably selected from the group consisting of two or more polyols, heterocyclic solvents, polyhydric ethers.

In addition, the ink composition for inkjet preferably further comprises a buffer or fungicide.

Accordingly, the present inventors have been observing the conventional problems, and as a result, they have been able to complete the present invention by designing a new molecular structure that can solve each problem and synthesizing a pigment having a new skeleton structure through the design of a new pigment, which is a naphthalene derivative. In addition to synthesizing new molecules having azo bonds with and naphthalene derivatives, new pigments having three naphthalene derivatives in the basic framework can be solved by dramatically improving light durability and water fastness. As shown in the structure of Formula 1 below, each skeleton has a perfect penetration effect on paper and the like by controlling the number of carboxyl and sulfonic acid groups appropriately as substituents for b, b, and la rings, thereby further improving water fastness. It can be effectively maintained. It has water solubility group of at least one carboxyl group or sulfonic acid group in each phenyl structure or naphthalene structure skeleton, so that it has molecular solubility and controls the number of these sulfonic acid groups and carboxyl groups appropriately so as to control moisture durability and light durability. The same properties could be improved.

[Formula 1]

In the above formula, W, X, Y, Z are as defined above.

The compound of Formula 1 may be synthesized by the following scheme.

Scheme 1

That is, the novel pigment | dye of general formula (I) can be synthesize | combined by carrying out the coupling reaction with the compound of general formula (III) after diazolating the compound of general formula (II).

On the other hand, the compound of the general formula (II) can be synthesized by diazotizing generally known derivatives of aniline and then using naphthyl amines as couplers. This general method is also commonly used in the synthesis of Food Black 2, as previously known.

Scheme 2

In addition, the compound of general formula (III) can be synthesize | combined by carrying out a coupling reaction with the compound of general formula (IV) by diazotizing a naphthyl amine derivative as follows.

Eq 3

Inkjet for inkjet using the new pigment of the formula 1 synthesized in the above process is preferably the following content and input conditions. The dye is used in the state of neutralizing carboxylic acid and sulfonic acid groups, and the counter ions used in this case are alkali metal salts such as sodium and potassium or ammonium, organic ammonium, and organic ammonium salts. It is possible to obtain a color density of the image which is excellent in that the content of the pigment is contained in a weight ratio of 0.5% to 20%, preferably 1% to 10%. As a solvent, water and an organic solvent having solubility in water and water can be mixed. As an organic solvent which can be mixed, alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, etc. And hydroxy groups such as ethylene glycol, propylene glycol, diethylene glycol, glycerol, two or more polyols, heterocyclic solvents such as tetrahydrofuran, 2-pyrrolidone, 2-methoxy ethyl alcohol, 2-butoxy ethyl alcohol, It is possible to use the same polyhydric ether.

In order to have basic properties according to other jetting mechanisms, it is preferable to add an appropriate amount of surfactant, and an appropriate amount of buffer and fungicide is used for long term storage.

The following presents a preferred embodiment to aid the understanding of the present invention. However, the following examples are merely provided to more easily understand the present invention, and the present invention is not limited to the following examples.

EXAMPLE

Example 1

First step

2.5 g of 2-amino-8-hydroxy-6-naphthalene sulfonic acid (gamma acid) was dissolved in 40 g of water with 0.8 g of 50% sodium hydroxide, and 3.6 g of 36% hydrochloric acid was added at room temperature. Ice was added to adjust the temperature to 0 ° C. to 15 ° C., and 0.7 g of sodium nitrite was added thereto, followed by stirring for about 1 hour. After removing excess sodium nitrite with sulfamic acid, the diazo reaction was completed.

In another reaction vessel, 3.2 g of 2-amino-8-hydroxy-3,6-naphthalene disulfonic acid (2R-ACID) was dissolved in 60 ml of water, such as 2.2 g of 50% sodium hydroxide, and the temperature was adjusted to 20 ° C. .

The diazo solution prepared above was added to the 2R-ACID solution for about 20 minutes to 60 minutes while maintaining the pH of the alkali to perform a coupling reaction. The intermediate thus synthesized is a compound of formula 12

[Formula 12]

2nd step

Dissolve 1.9 g of 5-amino isophthalic acid in 30 g of water with 1.6 g of 50% sodium hydroxide at room temperature, add 5.0 g of 36% hydrochloric acid, adjust the temperature to 0 ° C to 10 ° C by adding ice, and then add 0.7 g of sodium nitrite. It was added after dissolving. Sulfamic acid removed excess sodium nitrite.

In another reaction vessel, 2.2 g of 1-naphthylamine-7-sulfonic acid was dissolved in 0.8 g of sodium hydroxide solution in 20 ml of water at 60 ° C.

The diazo solution was added to the 1-naphthylamine-7-sulfonic acid solution to cause a coupling reaction. The final pH was maintained as an acid and stirred to obtain a compound of formula (13).

[Formula 13]

3rd step

3.0 g of 36% hydrochloric acid was added to the aqueous solution of Formula 13 synthesized in the second step, 0.7 g of sodium nitrite was dissolved, and then agitated at 10 ° C. to 50 ° C. for 1 to 3 hours to conduct a diazotization reaction. . After the reaction was completed, excess sodium nitrite was removed as sulfamic acid.

The dye having the above formula (7) was obtained by adding the finished solution of diazo to the solution of formula (12) prepared above while maintaining the pH at basic. Inks containing about 3% of this dye exhibited excellent print fastness and moisture fastness, and excellent print quality and color strength.

Example 2

First stage

2.5 g of 2-amino-8-hydroxy-6-naphthalene sulfonic acid (gamma acid) was dissolved in 40 g of water with 0.8 g of 50% sodium hydroxide, and 3.6 g of 36% hydrochloric acid was added at room temperature. Ice was added to adjust the temperature to 0 ° C. to 15 ° C., and 0.7 g of sodium nitrite was added thereto, followed by stirring for about 1 hour. After removing excess sodium nitrite with sulfamic acid, the diazo reaction was completed.

In another reaction vessel, 2.5 g of 2-amino-8-hydroxy-6-naphthalene sulfonic acid was dissolved in 60 mL of water, such as 2.2 g of 50% sodium hydroxide, and the temperature was adjusted to 20 ° C.

The diazo solution prepared above was added to the gamma acid solution for about 20 minutes to 60 minutes while maintaining the pH of the alkali to cause a coupling reaction. The intermediate thus synthesized is a compound of formula (14).

[Formula 14]

2nd step

After adding 1.4 g of metaamino benzoic acid to 3.0 g of 36% hydrochloric acid, stirring it thoroughly with 30 ml of water and stirring it at room temperature, adding ice to adjust the temperature to 0 ° C. to 10 ° C., and then dissolving 0.7 g of sodium nitrite. The mixture was stirred for about 1 hour to complete the diazo reaction, and excess sodium nitrite was removed with sulfamic acid.

In another reaction vessel, 1.4 g of 1-naphthylamine was dissolved in 20 ml of water at 60 ° C. using 1.2 g of 36% hydrochloric acid and adjusted to room temperature again.

The diazo solution was added to the 1-naphthylamine solution to cause a coupling reaction. The final pH was maintained as an acid and stirred to obtain a compound of Formula 15.

[Formula 15]

3rd step

3.0 g of 36% hydrochloric acid was added to the aqueous solution of Formula 15 synthesized in the second step, 0.7 g of sodium nitrite was dissolved, and then agitated at 5 ° C. to 40 ° C. for 1 to 3 hours to conduct a diazotization reaction. . After the reaction was completed, excess sodium nitrite was removed as sulfamic acid.

The diazo-completed solution was added to the solution of Formula 14 prepared above while maintaining the pH at a basic level, thereby obtaining a dye as in Formula 8. Inks containing about 3% of this dye exhibited excellent print fastness and moisture fastness, and excellent print quality and color strength.

Example 3

First stage

2.5 g of 2-amino-8-hydroxy-6-naphthalene sulfonic acid (gamma acid) was dissolved in 40 g of water with 0.8 g of 50% sodium hydroxide, and 3.6 g of 36% hydrochloric acid was added at room temperature. Ice was added to adjust the temperature to 0 ° C. to 15 ° C., and 0.7 g of sodium nitrite was added thereto, followed by stirring for about 1 hour. After removing excess sodium nitrite with sulfamic acid, the diazo reaction was completed.

In another reaction vessel, 2.5 g of 2-amino-8-hydroxy-6-naphthalene sulfonic acid (gamma acid) was dissolved in 60 ml of water, such as 2.2 g of 50% sodium hydroxide, and the temperature was adjusted to 20 ° C.

The diazo solution prepared above was added to the gamma acid solution for about 20 minutes to 60 minutes while maintaining the pH of the alkali to cause a coupling reaction. The intermediate thus synthesized is a compound of Formula 16 below.

[Formula 16]

2nd step

Dissolve 1.9 g of 5-amino isophthalic acid in 30 g of water with 1.6 g of 50% sodium hydroxide at room temperature, add 5.0 g of 36% hydrochloric acid, adjust the temperature to 0 ° C to 10 ° C by adding ice, and then add 0.7 g of sodium nitrite. The excess nitrite was removed by sulfamic acid.

In another reaction vessel, 1.4 g of 1-naphthylamine was dissolved in 20 ml of water using 1.2 g of 36% hydrochloric acid, which was readjusted at room temperature.

1-naphthylamine solution was added to the diazo solution for coupling reaction. The final pH was maintained as an acid and stirred to obtain a compound of formula 17.

[Formula 17]

3rd step

3.0 g of 36% hydrochloric acid was added to the aqueous solution of Formula 17 synthesized in the second step, 0.7 g of sodium nitrite was dissolved, and then agitated at 10 ° C. to 50 ° C. for 1 to 3 hours to conduct a diazotization reaction. . After the reaction was completed, excess sodium nitrite was removed as sulfamic acid.

The diazo-completed solution was added to the solution of Formula 16 prepared above while maintaining the pH at a basic level to obtain a dye as in Formula 9. Inks containing about 3% of this dye exhibited excellent print fastness and moisture fastness, and excellent print quality and color strength.

Example 4

The method of Example 3 above was carried out by dissolving 1.9 g of 1-naphthylamine-7-sulfonic acid in sodium hydroxide instead of 1.4 g of 1-naphthyl amine used in the second step of Example 3. And the rest was obtained in the same manner to obtain a dye of formula (10). Inks containing about 3% by weight of this pigment showed very good water fastness and light fastness and excellent print quality and color strength after printing.

Comparative example

An ink containing about 3% by weight of Food Black 2 pigment was used.

The moisture fastness, light fastness, sharpness and color intensity of the inks of Examples 1 to 4 and Comparative Examples were measured, and the results are shown in Table 1 below. Moisture fastness was measured after leaving the ink in paper for 24 hours in natural condition and drying it naturally. After immersing the print in water for exactly 1 minute under the same conditions, it measured the degree of the print out of the water. It was measured by the fade metric method in KS 0700/1985, "Daylight Fastness Test Method of Dyestuff". In addition, sharpness was visually observed and color intensity was measured with a densitometer.

Moisture fastness (%) ^a Light Fastness (%) ^b definition Color intensity Example 1 12 2.1 Great 1.32 Example 2  9 2.8 Great 1.30 Example 3  8 2.3 Great 1.38 Example 4 10 2.2 Great 1.35 Comparative example 90 10 - 1.23

a. Moisture fastness (%): Percentage of concentration lost (bleached) after soaking in water.

                   Lower means less color change.

b. Light Fastness (%): percentage of bleached concentration after 100 hours light resistance test.

                 Lower means less color change.

By securing a dye for ink with moisture durability, light durability and excellent print quality, a high quality dye for ink can be obtained without adding an additive.

Claims (8)

The black dye for inkjet ink whose free acid form is represented by following General formula (1). [Formula 1]

Wherein W is hydrogen or a carboxyl group and X, Y and Z represent hydrogen or sulfonic acid groups the same or differently. The black dye of claim 1, wherein the carboxylic acid and sulfonic acid of Formula 1 are neutralized to form an alkali metal salt, an ammonium salt, or an organic ammonium salt. The black dye according to claim 1, wherein the black dye is selected from the group consisting of compounds having Formula 7, Formula 8, Formula 9, Formula 10, and Formula 11. [Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

[Formula 11]

Diazotizing the compound of formula 5; Synthesizing the compound of Formula 1 by coupling the compound of Formula 5 to a diazotization reaction with a compound of Formula 6; The manufacturing method of the black dye for inkjet ink containing the process. [Formula 5]

[Formula 6]

Wherein W is hydrogen or a carboxyl group and X, Y and Z represent hydrogen or sulfonic acid groups the same or differently. Black dyes for inkjet inks which are alkali metal salts or ammonium salts or organic ammonium salts obtained by neutralizing the carboxylic acid and sulfonic acid groups of the formula (1) in free acid form; Solvent; Surfactants; Ink composition for ink jet containing. The ink composition of claim 5, wherein the black dye for inkjet ink is 0.1 wt% to 10 wt%. The solvent according to claim 5, wherein the solvent is water or a mixed solution of water and a water-soluble organic solvent, wherein the water-soluble organic solvent comprises an alcohol having 1 to 4 carbon atoms, a polyol having at least two hydroxyl groups, a heterocyclic solvent, and a polyhydric ether. Ink composition for an ink jet selected from the group consisting of. The ink composition of claim 5, wherein the ink composition for ink jet further comprises a buffer or a fungicide.