JP2005194493A - Monoazo pigment and coloring material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a monoazo pigment having a color tone of a carmine 6B pigment and capable of being widely utilized for color reproduction by tone reduction mixing, without containing rosin, by solving such a problem that use of a large amount of the rosin in a conventional pigment is necessary and indispensable for obtaining the highly transparent color tone given by the carmine 6B pigment and exhibiting high color-rendering properties in the color reduction mixing, and to provide a coloring material by using the same. <P>SOLUTION: This monoazo pigment is provided by combinedly conducting synthesis of the carmine 6B pigment and synthesis of a naphthol AS-based insoluble monoazo pigment, so as to conduct pigmentation at the same time. The coloring material is provided by using the pigment. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a monoazo pigment and a coloring material using the same. The monoazo pigment mentioned here is a pigment having a transparent and good color rendering property that can be obtained only with a Carmine 6B pigment using a large amount of rosin, and this performance can be obtained without rosin. It is composed of two different types of pigments composed of Carmine 6B pigment CIPR57: 1 and a naphthol AS-based insoluble monoazo pigment, and the composition ratio is not limited.
The naphthol AS-based insoluble monoazo pigment, which is one of the constituent pigments, means a red pigment that is pigmented only by a coupling reaction using naphthol ASs as a coupler component.
No matter what kind of pigment is used, this type of pigment is not limited because it has a preventive effect on crystal growth of the carmine 6B pigment when combined.
The naphthol ASs mentioned herein mean naphthol AS (2.3 hydroxy naphthoic acid anilide) and derivatives thereof.

Compounding the synthesis described in the claims is defined as follows.
That is, in order to prevent the crystal growth of the carmine 6B pigment by the action of the naphthol AS-based insoluble monoazo pigment, the two pigments are mixed as necessary, and a series of synthesis is performed together. It means to be pigmented.
The principle of the present invention is to prevent crystal growth of the constituent pigments used by combining the synthesis of different pigments.
A naphthol AS-based insoluble monoazo pigment is a pigment formed by reacting each diazo component and a coupler component only by a coupling reaction, and has only one synthesis step.
On the other hand, Carmine 6B pigment CIPR57: 1 is generally called a soluble monoazo lake pigment. A diazo component and a coupler component are reacted with each other to obtain a water-soluble dye by a coupling reaction. It consists of two synthesizing steps: a rake reaction for pigmenting, i.e., a pigmentation reaction. In the present invention, these syntheses are performed in combination.

The monoazo pigment of the present invention can be used for various colorants. The term “coloring material” as used herein refers to a material used in a color reproduction system that performs subtractive color mixing that turns black when mixed using the three primary colors, and in this case, means a material that performs a coloring role.
Typical examples of this color material include lithographic ink, gravure ink, flexographic ink and the like.

The present invention is particularly effective when used in a lithographic ink that requires a high level of performance, and has the highest utility value. A detailed description of the entire invention will be given.
The term “lithographic ink” means a general term for lithographic inks for sheet-fed printing and lithographic inks for off-wheel printing, including special inks such as offset ink, UV ink, newspaper ink, waterless ink, hybrid ink, and special ink. The lithographic ink expressed in
The lithographic ink is mainly used for lithographic process printing, which is the mainstream of lithographic printing. Process printing is a representative color reproduction system based on subtractive color mixing, and means multicolor printing.
In this case, the color tone of ink with good color rendering properties is required so that subtractive color mixing is more advantageous, and the color tone of Carmine 6B pigment containing a large amount of rosin as a pigment for this is now widely used all over the world. In this application, the Carmine 6B pigment which does not contain rosin has not been used at all because of its color tone. As used herein, rosin means a variety of natural rosins and derivatives thereof.
The color tone with high transparency obtained from the Carmine 6B pigment containing a large amount of rosin is a color tone that is indispensable for lithographic process printing with subtractive color mixing. In general, those containing approximately 20% rosin in the Carmine 6B pigment are widely used.
In the case of lithographic ink, carmine 6B pigment containing a large amount of rosin provides the best performance when the flushing method is used as an ink manufacturing method. Therefore, a press cake that is an aqueous dispersion of pigment is used as a lithographic ink manufacturing method. The flushing method used is well established.
The flushing method is a method of making ink directly from a press cake which is a water dispersion. Since crystal growth of the pigment can be minimized during ink production, it is highly transparent and good for color reproduction by subtractive color mixing. This method is widely used to make red ink having a color tone. Therefore, inking from powder is limited to special cases only in the case of lithographic ink. Since the flushing method cannot be used technically except for lithographic ink, it is generally used in powder form.

On the other hand, the challenge of obtaining the color tone of Carmine 6B pigment obtained only when rosin is used without rosin has been carried out in various places to date, but there is no definitive one, and the field of lithographic process printing However, at present, there is no lithographic ink using Carmin 6B pigment without rosin, and the possibility is not found. Furthermore, no rosin red pigment suitable for lithographic process printing is present in azo pigments or blends other than Carmine 6B. A rosin-free carmine 6B pigment that is not suitable for lithographic process printing can be easily obtained, but it is opaque and extremely poor in color, and for color reproduction by subtractive color mixing including lithographic ink, It cannot be used at all.

In the case of Carmine 6B pigment as a material for the color material for image formation that performs subtractive color mixing, for example, the following are the disadvantages of using rosin.
(1). With lithographic inks, printability is significantly negative.
(2). Water-based flexo inks and gravure inks, etc., have significantly negative stability and fluidity over time.
Therefore, the appearance of pigments having no rosin and having the color tone of the original Carmine 6B pigment has been continuously demanded in order to be effectively used for a wider variety of color materials.
Without rosin, at present, the color tone of Carmine 6B pigment becomes unclear, the transparency is greatly reduced, and the original color tone of Carmine 6B pigment is said to be reduced, resulting in subtractive color mixing including lithographic ink. It has a basic problem that it cannot be used as a color material for color reproduction.

It is generally known that the smaller the particle diameter of the pigment, the more advantageous in terms of transparency, sharpness, and concentration. In order to adjust the particle diameter of the pigment, a method of treating with a rosin at the time of synthesis of the pigment is generally used, and various performances are imparted thereby.
It seems that the addition of rosin inhibits the crystal growth of Carmine 6B pigment, resulting in fine and clear pigment particles.
From this point of view, in the case of the carmine 6B pigment, unless an effective substance replacing rosin is discovered, a carmine 6B pigment having a color tone suitable for subtractive color mixing cannot be obtained. In the past, various attempts have been made including the following patent documents, but none of them is a means for solving the problems to be solved by the present invention.
JP 7-49537 JP 2000-160047 JP 2000-160048

The problem to be solved by the present invention is to provide a pigment having a highly transparent color tone of the widely used carmine 6B pigment and not containing rosin, and to provide a coloring material effectively using the pigment. There is.
The color tone here means the transparency, hue, and density obtained only when a large amount of rosin is used in the pigmentation reaction in the synthesis of the Carmine 6B pigment, and the color using the subtractive color mixture that turns black by mixing the three primary colors. A pigment having a color rendering performance that can be widely used as a pigment used in a color material for reproduction.

Combining the synthesis of carmine 6B pigment and the synthesis of naphthol AS-based insoluble monoazo pigment, it is composed of two different types of pigments consisting of naphthol AS-based insoluble monoazo pigment and carmine 6B pigment obtained by pigmenting together. The monoazo pigment which does not contain rosin was made and the problem was solved by using this.
The present invention is based on a completely new concept of using a naphthol AS-based insoluble monoazo pigment instead of rosin for the purpose of preventing crystal growth in the pigmentation reaction of the carmine 6B pigment.
In principle, the naphthol AS-based insoluble monoazo pigment has the same behavior as the rosin crystal growth preventing effect.
In the case of rosin, the mechanism is effective as follows.
That is, the insoluble rosin is generally hydrophilized in the form of sodium soap or the like, and is first mixed thoroughly in a completely suspended state in a water-soluble dye for carmine 6B pigment. In this case, it is important to keep it completely suspended. Next, during the pigmentation reaction of Carmine 6B pigment, this is simultaneously converted into calcium soap, insolubilized in a completely mixed state while maintaining a complete suspension, oleophilic and fine contamination with a large surface area. This is believed to prevent crystal growth of the oleophilic carmine 6B pigment.
On the other hand, when a naphthol AS-based insoluble monoazo pigment is used, the diazo component or coupler component is completely mixed in the diazo component for coupler 6B pigment or coupler component or dye in a completely suspended state. In this case, it is important to keep it completely suspended as in the case of rosin. Next, when a coupling reaction is sequentially performed, a naphthol AS-based insoluble monoazo pigment is produced in the water-soluble dye for carmine 6B pigment.
In this case, the naphthol AS-based insoluble monoazo pigment is completely insolubilized while maintaining a completely suspended state, and becomes lipophilic to form fine contaminants having a large surface area, simultaneously with this reaction, or Crystal growth of the oleophilic carmine 6B pigment that occurs in the subsequent pigmentation reaction of the carmine 6B pigment is prevented thereby, and the mechanism is exactly the same as in the case of rosin, and only the means are different.

Although there is no carmine 6B pigment that has satisfactory color rendering properties such as transparency, density, and hue without rosin, the present invention is the first to develop a rosin-free pigment with the original color tone of carmine 6B pigment that can be fully satisfied with color reproduction by subtractive color mixing. It became possible to do. And it became possible to give the merit of not containing rosin.

As a result of not using rosin in the pigment, the metal soap, which is the calcium soap of rosin, is no longer present in the colorant using this pigment. For example, in the case of lithographic ink, the printability is significantly improved. . In particular, suitability for long runs such as dirt, emulsification, and roller stripping, which are problems in lithographic process printing, is remarkably improved. Improvements are also expected in the various resistance aspects of the printed matter.
From a practical point of view, naphthol AS-based insoluble monoazo pigments are preferably those that are easy to control color tone, easy to handle, easy to synthesize, and advantageous in price.
CIPR 146, CIPR 147, CIPR 184 and the like are better from a practical point of view, but are not limited thereto. Further, there is no problem even if two or more naphthol AS-based insoluble monoazo pigments are used.
For the purpose of preventing pigment crystal growth, it is understood that the principle of the present invention, in which compounding of different pigments is combined to form a pigment, can be widely used other than the present invention in subsequent studies. 6B pigment CIPR57: 1 and naphthol AS-based insoluble monoazo pigment are limited to use, but other types of soluble azo lakes, other than naphthol AS-based insoluble monoazo pigments, In the future, the development of other objects than the present invention can be expected, such as using one different from the present invention.

By providing the monoazo pigment and coloring material of the present invention, the carmine 6B pigment obtained only by using a large amount of rosin retains the original color tone having good color rendering properties, which is the biggest drawback of the conventional carmine 6B pigment. Poor suitability due to the inclusion of rosin could be completely improved.

The point is that the naphthol AS-based insoluble monoazo pigment is present in a state having an effect of preventing crystal growth during the pigmentation reaction in the synthesis of the carmine 6B pigment.
In general, the coupling reaction of the naphthol AS-based insoluble monoazo pigment, that is, the pigmentation reaction, has a fast reaction speed, and conversely, the rake reaction of the carmine 6B pigment, that is, the pigmentation reaction, tends to be very slow. Therefore, when the synthesis is performed in combination, both methods are produced simultaneously, and the naphthol AS-based insoluble monoazo pigment effectively acts to prevent crystal growth of the carmine 6B pigment. However, it is simplest and most reliable to start the pigmentation reaction of the Carmine 6B pigment last.

If the synthesis conditions set in claim 1 are used, the object can be achieved by any method. The composition ratio of the carmine 6B pigment and the naphthol AS-based insoluble monoazo pigment is not limited at all, but it is better to reduce the use of the naphthol AS-based insoluble monoazo pigment from a practical viewpoint such as price.
In other respects, for example, it is better to select a synthesis condition that seems to be advantageous for the color tone, but the synthesis of the carmine 6B pigment itself is generally performed and there is no problem, and the naphthol AS-based insoluble monoazo pigment is satisfactory. There is no problem with the synthesis of.
Further, various treatments other than synthesis and additives are used as needed and there is no problem.
Since it is used for a special purpose, rosin is consciously added, and there is no problem in the synthesis in the present invention, and further significant transparency can be achieved.
When used as a powder, it is advantageous to increase the dispersibility by chemical treatment or physical treatment such as jet mill grinding.

Hereinafter, the present invention will be described in more detail.
Unless otherwise specified, parts mean parts by weight and% means% by weight.
Each Example or Comparative Example was modified and implemented based on the following model recipe.

The model recipe for Carmine 6B pigment (CIPR 57: 1) is as follows.
Suspend 14.3 parts of 1-amino-4-methylbenzene-2-sulfonic acid in 400 parts of water, and add ice while stirring to 8 ° C. or less. Thereto is added 5.4 parts of sodium nitrite dissolved in 30 parts of water. After stirring for 5 to 10 minutes, diazotization is performed by adding 8.7 parts of 35% hydrochloric acid at 5 ° C. or lower. This is the diazo component. On the other hand, 14.5 parts of β-oxynaphthoic acid is dissolved at 30 ° C. in a solution obtained by dissolving 7.1 parts of caustic soda in 300 parts of water. Further, water is added to make a total amount of 700 parts, which is used as a coupler component. Using a diazo component and a coupler component, a coupling reaction is performed at 20 ° C. or lower to form a dye. The pH of the coupling solution is 11.0 to 13.0. After stirring for 30 minutes, 6.8 parts of rosin is added to a separately prepared rosin solution, that is, a solution of 1.0 part of caustic soda in 80 parts of water, heated, and the dissolved rosin solution is added. A solution obtained by dissolving a part in 40 parts of water is added to perform a lake reaction to form a pigment. The mixture was stirred for 3 hours or more to complete the rake reaction, that is, the pigmentation reaction.
After neutralization with formic acid (pH 8 to 8.5), heat to 80 ° C. and immediately wash with filtered water.
A press cake of 39.5 parts of monoazo lake pigment (CIPR 57: 1) was obtained. The rosin content is 20%. The above is the standard for Carmine 6B pigment synthesis, but the coupling temperature, pH, etc. are preferably carried out on a case-by-case basis under conditions that favor color tone.

The model formulation of the naphthol AS-based insoluble monoazo pigment CIPR146 is as follows.
Dissolve 20 parts of 3-amino-4-methoxy-benzanilide in 33.7 parts of 35% hydrochloric acid, add ice and cool to 0 ° C. to a total volume of 400 parts. A solution obtained by dissolving 5.7 parts of sodium nitrite in 50 parts of water is added dropwise thereto, and further stirred at 5 ° C. or lower for 30 minutes. Then 22.2 parts of sodium nitrite are added. The total amount is 640 parts. This is the diazo component. On the other hand, 6.6 parts of caustic soda were dissolved in 200 parts of water, and 29.6 parts of 4′-chloro-3-hydroxy-2 ′, 5′-dimethoxy-2-naphthanilide (naphthol AS-LC) was added thereto. Heat to ° C and dissolve. The total amount is 960 parts. This is a coupler component. A coupling reaction is performed using a coupler component and a diazo component to form a pigment. The mixture was heated to 60 ° C., stirred for 30 minutes and then heated to 90 ° C. to obtain 50.4 parts of a naphthol AS-based insoluble monoazo pigment (CIPR146) press cake. The above is the standard for CIPR 146 synthesis, but it is preferable to perform the coupling temperature / pH and other conditions that are advantageous for color tone on a case-by-case basis.

In this case, CIPR 147 is obtained when naphthol AS-TR is used as the coupler component and naphthol AS-TR is used as the coupler component, CIPR 31 is obtained when naphthol AS-BS is used, and CIPR 32 is obtained when naphthol AS is used.

In addition, various naphthol AS-based insoluble monoazo pigments can be obtained by changing the diazo component and the type of naphthol AS as a coupler component.
For example, when naphthol AS-D is used as a coupler component and Scarred Base G (2-methyl-5-nitroaniline) manufactured by Daito Chemical Industry is used as a diazo component, CIPR17 is obtained, and Daito Chemical Industries, Ltd. is used as a diazo component. CIPR14 is obtained using red base 3GL (2-nitro-4-chloroaniline).

The coupler component for CIPR146 pigment is added to the dye for carmine 6B pigment obtained by the coupling reaction so that CIPR146 pigment equivalent to 20% can be formed as the finished pigment, and then the diazo component for CIPR146 pigment is added, and CIPR146 pigment is added. Generated and coexisted. Next, a rake reaction for pigmentation of a dye for carmine 6B pigment, ie, a pigmentation reaction, was performed using calcium chloride. After stirring for 3 hours, the mixture was neutralized, heated, washed and washed with water to obtain a press cake of 32% pigment content of a monoazo pigment comprising 80% of Carmine 6B pigment and 20% of CIPR146 pigment. Rosin is not used.

The coupler component for carmine 6B pigment and the coupler component for CIPR146 pigment were mixed so that the resulting pigment was a mixture of 90% carmine 6B pigment and 10% CIPR146 pigment. A diazo component for Carmine 6B pigment was added to this, and subsequently a diazo component for CIPR146 pigment was added to complete the coupling reaction. This allowed CIPR146 pigment to coexist in the dye for Carmine 6B pigment.
Thereafter, a rake reaction of a dye for carmine 6B pigment, ie, a pigmentation reaction was carried out with calcium chloride without using rosin. The mixture was stirred for about 5 hours, neutralized with formic acid, heated at 80 ° C., washed with loca, and washed with water to obtain a press cake of a monoazo pigment consisting of 90% carmine 6B pigment with 30% pigment content and 10% CIPR146 pigment. Rosin is not used.

A coupler component for the carmine 6B pigment and a coupler component for the CIPR146 pigment were mixed so that the CIPR146 pigment was 15% of the finished pigment to obtain a coupler component. On the other hand, a diazo component for Carmine 6B pigment and a diazo component for CIPR146 pigment were mixed to form a diazo component. Thereafter, a coupling reaction was performed in which the diazo component was added to the coupler component. At that time, calcium chloride necessary for the pigmentation reaction of the carmine 6B pigment was previously added to the diazo component. Carmine 6B pigment and CIPR146 pigment were synthesized simultaneously and pigmented together. Stir for about 4 hours, confirm that the pigmentation reaction of carmine 6B pigment has reached the end point, neutralize with formic acid, heat at 80 ° C, wash with water, wash with water, 32% pigment content of carmine 6B pigment is 85% A press cake of a monoazo pigment comprising 15% of CIPR146 pigment was obtained. Rosin is not used.

In Example 2, the synthesis was performed so that the resulting pigment was a mixture of 95% Carmine 6B pigment and 5% CIPR146 pigment. Others were the same as in Example 2, and a press cake was obtained in which the content of the monoazo pigment consisting of 95% of the Carmine 6B pigment and 5% of the CIPR146 pigment was 32%. Rosin is not used.

In Example 2, the diazo component for CIPR 146 pigment is first charged, and then the diazo component for Carmine 6B pigment is charged after changing the order of charging the diazo component into the coupler component. CIPR146 pigment was allowed to coexist in the dye for use. Thereafter, rake formation was performed with calcium chloride without using rosin, and a pigmentation reaction of Carmine 6B pigment was performed. Others were the same as in Example 2, and a press cake of a monoazo pigment comprising 90% of Carmine 6B pigment and 10% of CIPR146 pigment was obtained.
The pigment content of the press cake was 30%. Rosin is not used.

The press cake obtained in Example 1 was dried and pulverized to obtain a powder. In addition, the powder was sufficiently pulverized to increase the dispersibility of the pigment. Rosin is not used.

In Example 2, instead of the coupler component of CIPR146 pigment (naphthol AS-LC), the coupler component of CIPR147 pigment (naphthol AS-TR) was used, and CIPR147 pigment comprised 10% and Carmine 6B pigment comprised 90% 32 A press cake of monoazo pigment with% pigment content was obtained. Others are the same as in Example 2. Rosin is not used.

In Example 2, instead of the coupler component of CIPR146 pigment (naphthol AS-LC), the coupler component of CIPR32 pigment (naphthol AS) was used, and 30% pigment comprising 10% CIPR32 pigment and 90% carmine 6B pigment. A press cake of content monoazo pigment was obtained. Others are the same as in Example 2. Rosin is not used.
(Comparative Example 1)

In the synthesis of the carmine 6B pigment, the carmine 6B pigment was synthesized so that rosin was 0%. A press cake with 30% pigment content was obtained.
(Comparative Example 2)

In the synthesis of the carmine 6B pigment, the carmine 6B pigment was synthesized so that the rosin was 20%. A press cake with 32% pigment content was obtained.
(Comparative Example 3)

A slurry of freshly prepared Carmine 6B pigment synthesized in Comparative Example 1 (90% pigment content) and a freshly prepared CIPR146 pigment slurry (10% pigment content) were blended, mixed well, and then washed with water. -It filtered and it was set as the press cake of the monoazo pigment. Rosin is not used.
(Comparative Example 4)

In Example 2, the coupler component for CIPR146 pigment was not used as the coupler component, and the total amount of the required coupler was replaced with the coupler component for Carmine 6B pigment. The diazo component for Carmine 6B pigment was added to this as in Example 2, followed by the addition of the diazo component for CIPR146 pigment to complete the coupling. Thereafter, rake formation is performed with calcium chloride without using rosin.
The mixture was stirred for about 5 hours, neutralized with formic acid, heated at 80 ° C., washed with water and washed with water to obtain a pigment press cake having a pigment content of 30%. Others were the same as in Example 2. Rosin is not used. As a result, the pigmentation was incomplete.
(Comparative Example 5)

The press cake of Carmine 6B pigment synthesized in Comparative Example 2 was dried and pulverized to obtain a powder. Contains 20% rosin.

The pigments produced in Examples 1 to 5 and Examples 7 to 8 and the pigments produced in Comparative Examples 1 to 4 were evaluated with a lithographic ink that is representative of color reproduction by subtractive color mixing. did. Each was converted into a lithographic ink and used for testing.
Ink was made with a test flasher and a three-roll mill, and flushed under certain conditions to make ink. Ink formulation is done with 16 parts of pigment, 60 parts of binder (GT150 manufactured by Toshin Oil & Fats), 24 parts of # 7 petroleum solvent, after flushing, kneading once with a roll, and if necessary, the amount of solvent and the amount of binder are slightly The test was carried out by controlling the tack to 8.0 ± 0.5 / 30 ° C. and flow 18 ± 0.5 / 20 ° C.

In the color tone test, as a general method that is widely used at present, a sample is prepared on high-quality paper under the same conditions, and a visual comparison is made by relative comparison.
In terms of hue, transparency, and density, an ink sample having a good color tone using Comparative Example 2 in which a large amount (20%) of rosin was used was indicated as A. In addition, the ink sample display using the carmine 6B of Comparative Example 1 having a rosin level of 0% which cannot be used for process printing was defined as C, and each of the Examples A, B and C was evaluated in three stages.
In Example 1, the color tone is good with display A, and no rosin is contained.
In Example 2, the display A has a good color tone and does not contain rosin.
In Example 3, the display A has a good color tone and does not contain rosin.
In Example 4, the color tone is good with display A and no rosin is contained.
In Example 5, the color tone is good with display A, and no rosin is contained.
Example 7 does not contain rosin according to the indication A.
Example 8 does not contain rosin according to Display A.
In Comparative Example 1, the color tone is poor in the display C, and no rosin is contained.
In Comparative Example 2, the color tone is good with display A, and rosin is contained in a large amount (20%).
Comparative Example 3 has a large color tone with the display C and does not contain rosin.
In Comparative Example 4, flushing was not possible and ink could not be made.
As described above, in the examples based on the description of the claims, the test results are all transparent pigments of carmine 6B pigments obtained with a rosin-free pigment and using a large amount of rosin. It was confirmed that the color tone had good reproducibility.

Furthermore, an emulsification coloring test and an interface test were performed and evaluated as marks for the printability of inks using the pigments obtained in these Examples. The result is as follows.
Example 1 has no emulsion coloring. The interface test was 3.0.
Example 2 has no emulsion coloring. The interface test was 3.0.
Example 3 has no emulsion coloring. The interface test was 3.0.
Example 4 has no emulsion coloring. The interface test was 3.0.
Example 5 has no emulsion coloring. The interface test was 3.0.
Example 7 has no emulsion coloring. The interface test was 3.0.
Example 8 has no emulsion coloring. The interface test was 3.0.
Comparative Example 2 is large in emulsion coloring. The interface test was 5.0.
In the emulsification coloring test, 50 g each of ink and tap water are mixed using a Duke emulsification tester, and the coloring of the emulsified water is observed after 10 minutes.
In the interface test, IPA is put into tap water, in which case the IPA contamination percentage is changed, and a certain amount of ink is placed on the surface of the water. Use smaller, better.
Those using the pigments of the examples were clearly good in all tests.

Using the monoazo pigment powder obtained in Example 6 and the carmine 6B pigment powder obtained in Comparative Example 5, the effect of the aqueous flexo ink mainly using powder among the color reproduction color materials was checked. Ink formation was performed by mixing 3 mm glass beads of the same amount as the ink material into a 200 cc mayonnaise bin, using a paint conditioner, and vibrating for 1 hour.
The ink formulation used for making the ink used a pigment content of 35% and a binder (30% John Crill 70, 29.2%, water 30.8%, IPA 5%, manufactured by Johnson Polymer). After kneaded meat, this was thinned to the same level with a binder.
In the ink evaluation, the color tone was determined by visual observation after drying on a hand-held substrate and drying. The viscosity was measured with a Zancup. At the same time, the discoloration and viscosity change over time for one week was stored and checked at 20 ° C.
As for the evaluation results, the color tone using the pigment obtained in Example 6 was more transparent and the color tone better than that using the pigment obtained in Comparative Example 5.
As for fluidity and change with time, any of the pigments of Example 6 were good, but those of Comparative Example 5 were inferior and showed a tendency to be even worse with time.

1. By using the pigment of the present invention, it has become possible to provide an unprecedented color material having good performance in a color reproduction system by various subtractive color mixing and having suitability for each purpose of use.
2. In particular, the provision of lithographic inks has greatly improved the suitability of red printing, which is currently the most troublesome of lithographic process printing, and has been a brake for streamlining and standardization of printing, and is a breakthrough in lithographic process printing. Can be expected.

Claims (2)

A monoazo pigment characterized in that the synthesis of Carmine 6B pigment and the synthesis of a naphthol AS-based insoluble monoazo pigment are combined and pigmented together. A color material comprising the monoazo pigment according to claim 1.