KR102696391B1 - Method of manufacturing aqueous pigment ink of self-dispersible pigment dispersion - Google Patents

Abstract

The present invention discloses a method for producing an aqueous pigment ink using a self-dispersing pigment dispersion, which can provide a pigment ink having improved dispersibility and not harmful to the human body, including a step (S110) of synthesizing a diazonium salt of a precursor of a diazo compound, and a step (S120) of synthesizing violet, cyan, and yellow diazo pigments by reacting the diazonium salt with a coupler component,

Description

{METHOD OF MANUFACTURING AQUEOUS PIGMENT INK OF SELF-DISPERSIBLE PIGMENT DISPERSION}

The present invention relates to a method for producing an aqueous pigment ink using a self-dispersing pigment dispersion, which can provide a high-yield pigment ink having improved water dispersibility and colorfastness and which is not harmful to the human body.

As is known, pigments commonly used as colorants for inkjet printing inks are divided into organic pigments and inorganic pigments. Organic pigments are pigments mainly composed of organic compounds, which are precipitated by adding metal salts to water-insoluble dyes or water-soluble dyes. They come in a variety of colors, have good coloring power, are vivid, and come in a variety of colors, but are expensive. Examples include insoluble azo pigments, azo lake pigments, condensed azo pigments, and metal salt azo pigments.

In addition, inorganic pigments are chemically inorganic pigments, and are mineral pigments. They are used as natural minerals, or manufactured through processing and grinding, or manufactured using metal compounds such as zinc, titanium, lead, iron, copper, and chromium as raw materials. Compared to organic pigments, they are opaque and have insufficient concentration, but they have good light and heat resistance, do not dissolve in organic solvents, and are inexpensive.

On the other hand, unlike dyes, pigments do not dissolve in water, so it is important to disperse them in water as fine particles. However, pigments are difficult to maintain in the form of single crystal particles, and are rather obtained as large aggregates of crystals. The particle size distribution of the aggregates is wide, making it difficult to spray evenly through an inkjet nozzle.

In addition, various surfactants and aqueous resins are used as dispersants to improve dispersibility, make pigment particles easily wettable in water, and prevent pigment particles from settling. Such dispersants include surfactants such as anionic or nonionic auxiliaries, and representative surfactants include nonylphenol ethoxylate and octylphenol ethoxylate. However, nonylphenol ethoxylate and octylphenol ethoxylate are known to be a type of environmental hormone that can cause endocrine disorders, liver and kidney damage, and their use is gradually being prohibited.

Republic of Korea Patent Publication No. 10-2165470 (October 14, 2020) Republic of Korea Patent Publication No. 10-1670771 (October 31, 2016)

The technical problem to be achieved by the present invention is to provide a method for manufacturing a self-dispersing pigment dispersion aqueous pigment ink, which has improved water dispersibility and color, and can provide a high yield pigment ink that is not harmful to the human body.

In order to achieve the above-mentioned object, an embodiment of the present invention provides a method for producing an aqueous pigment ink using a self-dispersing pigment dispersion, comprising the steps of: synthesizing a diazonium salt of a precursor of a diazo compound; and reacting the diazonium salt with a coupler component to synthesize violet, cyan, and yellow diazo pigments, respectively.

Here, the diazonium salt synthesis step may be comprised of the steps of dissolving p-tuloidine-2-sulfonic acid in a 0.5 M KOH aqueous solution, cooling to 0°C, adding a 20 wt% sodium nitrite aqueous solution dropwise, and maintaining the temperature at 2°C or lower for 1 hour and adding an HCl solution dropwise.

In addition, the step of synthesizing the violet diazo pigment may include a step of dissolving pigment violet 19 in a 0.5 M KOH aqueous solution and then cooling to 15°C to produce a solution, a step of adding a suspension of the diazonium salt to the solution and stirring at room temperature to synthesize a violet pigment, and a step of filtering the violet pigment and then diluting it in distilled water so that the pigment solid content becomes 10 wt%.

In addition, the cyan diazo pigment synthesis step may be comprised of a step of dissolving pigment blue 15:3 in a 0.5 M KOH aqueous solution and then cooling to 15°C to produce a solution, a step of adding a suspension of the diazonium salt to the solution and stirring at room temperature to synthesize a cyan pigment, and a step of filtering the cyan pigment and then diluting it in distilled water so that the pigment solid content becomes 10 wt%.

In addition, the yellow diazo pigment synthesis step may be comprised of a step of dissolving Pigment Yellow 155 in a 0.5 M KOH aqueous solution and then cooling to 15°C to produce a solution, a step of adding a suspension of the diazonium salt to the solution and stirring at room temperature to synthesize a yellow pigment, and a step of filtering the yellow pigment and then diluting it in distilled water so that the pigment solid content becomes 10 wt%.

According to the present invention, there is an effect of being able to provide a pigment ink having improved water dispersibility and color and having a high yield that is not harmful to the human body.

Figure 1 is a schematic flow chart illustrating a method for manufacturing a self-dispersing pigment dispersion aqueous pigment ink according to an embodiment of the present invention.
Figure 2 illustrates a diazonium salt synthesis step of the method for manufacturing a self-dispersing pigment dispersion aqueous pigment ink of Figure 1.
Figure 3 illustrates ART analysis and UV-Vis analysis, respectively, at the violet diazo pigment synthesis step of the method for manufacturing a self-dispersing pigment dispersion aqueous pigment ink of Figure 1.
Figure 4 illustrates ART analysis and UV-Vis analysis, respectively, at the cyan diazo pigment synthesis step of the method for manufacturing a self-dispersing pigment dispersion aqueous pigment ink of Figure 1.

Hereinafter, an embodiment of the present invention having the above-described features will be described in more detail with reference to the attached drawings.

The method for manufacturing an aqueous pigment ink using a self-dispersing pigment dispersion according to an embodiment of the present invention comprises a step (S110) of synthesizing a diazonium salt of a precursor of a diazo compound, and a step (S120) of reacting the diazonium salt with a coupler component to synthesize violet, cyan, and yellow diazo pigments, respectively, thereby providing a pigment ink having improved dispersibility and not harmful to the human body.

Hereinafter, with reference to FIGS. 1 to 4, a method for manufacturing a self-dispersing pigment dispersion aqueous pigment ink having the aforementioned composition will be specifically described as follows.

First, in the diazonium salt synthesis step (S110), a diazonium salt of a precursor of a diazo compound is synthesized.

Specifically, referring to FIG. 2, the diazonium salt synthesis step (S110) may include a step (S111) of dissolving p-toluidine-2-sulfonic acid in a 0.5 M KOH aqueous solution at room temperature, a step (S112) of cooling to 0°C, and then adding a 20 wt% sodium nitrite aqueous solution dropwise to convert 2-nitroaniline into a diazonium salt form to produce a precursor of a diazo compound, and a step (S113) of adding a HCl solution (10 M, 14.15 ml) dropwise to produce a precursor of a diazo compound while maintaining the temperature below 2°C for 1 hour using a cooling/heating circulator due to the continued exothermic reaction.

Next, in the diazo pigment synthesis step (S120), a diazonium salt is reacted with a coupler component to synthesize violet, cyan, and yellow diazo pigments, respectively.

Specifically, among the diazo pigment synthesis steps (S120), the violet diazo pigment synthesis step (S121) includes a step (S121a) of dissolving pigment violet 19 in a 0.5 M KOH aqueous solution and cooling to 15°C to generate a solution, a step (S121b) of adding a suspension of a diazonium salt to the solution and stirring at room temperature to synthesize a violet pigment, and a step (S121c) of filtering the violet pigment and diluting it in distilled water so that the pigment solid content becomes 10 wt%, thereby finally obtaining a reaction product of pigment violet 19 + diazonium salt.

Here, [Table 1] illustrates the synthetic formula of a violet diazo pigment, and [Table 2] illustrates the manufacturing results of a violet diazo pigment.

Materials Input (g) mole Molar ratio p-toluidine-2-sulfonic acid 4 0.016 1.0 Hydrochloric acid(37%) 14.19 - - NaNO ₂ 9.29 - - KOH 23.21 - - Water 474.82 - - Pigment violet 19 40 0.128 8.0

Materials Usage (g) mole M.W. transference number(%) p-toluidine-2-sulfonic acid 4 0.016 187.21 - Pigment violet 19 40 0.128 312.32 - Pigment violet 19 + Diazonium salt 37.23 0.075 497.52 52

In addition, Fig. 3 (a) and [Table 3] are examples of ART analysis at the synthesis stage of a violet diazo pigment. The purified violet diazo pigment was analyzed by the ART method, and the presence of a hydroxy structure was confirmed as an absorption peak was confirmed at 3,100 cm ^-1 , and the presence of a diazole structure was confirmed as an absorption peak was confirmed at 2,300 cm ^-1 .

IR absorption(cm ^-1 ) Group Compound class 3100 O-H stretch Hydroxy 2305 C-N=N-C peak Diazole

In addition, Fig. 3 (b) illustrates UV-Vis analysis at the stage of synthesizing a violet diazo pigment. When comparing the analysis results before and after purification, it can be confirmed that the absorption peak after the reaction is increased due to the improvement in water dispersibility by the sulfonic group.

Meanwhile, the diazo pigment synthesis step (S120) of the cyan diazo pigment synthesis step (S122) includes a step (S122a) of dissolving pigment blue 15:3 in a 0.5 M KOH aqueous solution and cooling to 15°C to generate a solution, a step (S122b) of adding a suspension of a diazonium salt to the solution and stirring at room temperature for 2 hours to synthesize a cyan pigment, and a step (S122c) of diluting in distilled water by pouring the solution twice or more so that the pigment solid content becomes 10 wt% to remove residual reactants after filtering the cyan pigment, so that a final reaction product of pigment blue 15:3 + diazonium salt can be obtained.

Here, Fig. 4 (a) illustrates ART analysis in the cyan diazo pigment synthesis step, where the presence of a hydroxy structure can be confirmed by the confirmation of an absorption peak at 3,100 cm ^-1 , and the presence of a diazole structure can be confirmed by the confirmation of an absorption peak at 2,300 cm ^-1 .

In addition, Fig. 4 (b) illustrates UV-Vis analysis, respectively. When comparing the analysis results before and after purification, it can be confirmed that the absorption peak after the reaction is higher, and the water dispersibility due to the sulfone group of p-tuloidine-2-sulfonic acid is increased, and it can be confirmed that light is better blocked by the evenly dispersed particle size.

Meanwhile, among the diazo pigment synthesis steps (S120), the yellow diazo pigment synthesis step (S123) includes a step (S123a) of dissolving pigment yellow 155 in a 0.5 M KOH aqueous solution and cooling it to 15°C to generate a solution, a step (S123b) of adding a suspension of a diazonium salt to the solution and stirring it at room temperature for 2 hours to synthesize a yellow pigment, and a step (S123c) of filtering the yellow pigment and diluting it in distilled water by pouring it twice or more so that the pigment solid content becomes 10 wt% to remove residual reactants, so that a final reaction product of pigment yellow 155 + diazonium salt can be obtained.

Here, [Table 4] shows an example of ART analysis of a yellow diazo pigment. The presence of a hydroxy structure can be seen as an absorption peak is confirmed at 3,100 cm ^-1 , and the presence of a diazole structure can be seen as an absorption peak is confirmed at 2,300 cm ^-1 .

IR absorption(cm ^-1 ) Group Compound class 3100 O-H stretch Hydroxy 2305 C-N=N-C peak Diazole

In addition, although not shown separately, when analyzing the purified yellow diazo pigment using the UV-Vis method, comparing the analysis results before and after purification, it can be confirmed that the absorption peak after the reaction is high, and it can be confirmed that the water dispersibility due to the sulfone group of p-toluidine-2-sulfonic acid is increased, and the light is better blocked by the evenly dispersed particle size.

Therefore, by the composition of the method for manufacturing a water-based pigment ink using a self-dispersing pigment dispersion as described above, a pigment ink having improved water dispersibility and chromaticity and having a high yield that is not harmful to the human body can be provided.

The embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

S110: Diazonium salt synthesis step S111: Dissolution step
S112: Sodium nitrite solution dropwise addition step S113: HCl solution dropwise addition step
S120: Diazo pigment synthesis step
S121: Synthesis step of violet diazo pigment
S122: Cyan diazo pigment synthesis step
S123: Yellow Diazo Pigment Synthesis Step

Claims (5)

A step of synthesizing a diazonium salt of a precursor of a diazo compound; and
A step of reacting the above diazonium salt with a coupler component to synthesize violet, cyan, and yellow diazo pigments, respectively;
The above diazonium salt synthesis step is,
A method for producing a diazo compound precursor, comprising the steps of: dissolving p-tuloidine-2-sulfonic acid in a 0.5 M KOH aqueous solution; cooling to 0°C; adding 20 wt% sodium nitrite aqueous solution dropwise; converting 2-nitroaniline into a diazonium salt; and adding HCl solution dropwise while maintaining the temperature at 2°C or lower for 1 hour using a cooling/heating circulator.
The above violet diazo pigment synthesis step comprises a step of dissolving pigment violet 19 in a 0.5 M KOH aqueous solution and then cooling to 15°C to produce a solution, a step of adding a suspension of the diazonium salt to the solution and stirring at room temperature to synthesize a violet pigment, and a step of filtering the violet pigment and then diluting it in distilled water so that the pigment solid content becomes 10 wt%.
The above cyan diazo pigment synthesis step comprises a step of dissolving pigment blue 15:3 in a 0.5 M KOH aqueous solution and cooling to 15°C to produce a solution, a step of adding a suspension of the diazonium salt to the solution and stirring at room temperature to synthesize a cyan pigment, and a step of filtering the cyan pigment and then diluting it in distilled water so that the pigment solid content becomes 10 wt%.
The above yellow diazo pigment synthesis step is characterized by comprising the steps of dissolving pigment yellow 155 in a 0.5 M KOH aqueous solution and then cooling to 15°C to produce a solution, adding a suspension of the diazonium salt to the solution and stirring at room temperature to synthesize a yellow pigment, and then filtering the yellow pigment and diluting it in distilled water so that the pigment solid content becomes 10 wt%.
Method for manufacturing water-based pigment ink using self-dispersing pigment dispersion. delete delete delete delete