JP2804431B2 - Pigment composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disazo pigment composition suitable as a lithographic ink pigment capable of performing high-definition printing.

[0002]

2. Description of the Related Art In recent years, with the remarkable progress in printing technology, there has been an increasing demand for high-quality, high-quality printed matter. However, the higher the quality of printed matter, the higher the reproducibility of halftone dots is usually required. In the case of lithographic printing performed on a delicate balance of "ink / fountain solution", very high quality printing is required. Technology is required.

[0003] More specifically, when the "water uptake of ink" during printing becomes too large, the viscosity of the ink during printing decreases, leading to excessive emulsification, resulting in thick dots and conspicuous background stains. If the amount of "ink uptake" is too small, ink will adhere to the non-image area of the plate and the dot gain (thickness of halftone dots) will not be measurable. Is known to be significantly reduced. Incidentally, in the prior art, as a measure for preventing excessive emulsification, one method has been taken to minimize the introduction of a compound which promotes hydrophilicity in a pigment such as a surfactant or an amine-based treating agent. .

[0004] Separately from this, a method of preventing the excessive emulsification by setting the ink viscosity to be slightly higher is also generally performed, but this tends to lower the water intake of the ink and to slow the emulsification rate at the same time. . In this extreme case, water droplets appear on the ink film on the printing plate immediately after passing through the ink applying roller, and the dots of the printed matter after printing appear. There are things.

[0005] In particular, a pigment in which a part of a heterogeneous compound is introduced into a coupling component, such as the pigment described in Example 1 of JP-B-55-49087, or a pigment particle obtained by aging at low temperatures after coupling. For pigments that have stopped growing,
Since the pigment obtained is transparent, the viscosity of the ink increases, and such a phenomenon is likely to occur.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a disazo pigment composition for lithographic ink capable of performing high-definition printing. .

[0007]

The above object is achieved by the present invention described below. That is, the present invention uses an acetoacetanilide compound as a coupling component and prepares 3,3′-
A disazo pigment composition comprising a diazo-tetrazide compound and a tetrazide compound of a diamine of the following formula I, which are coupled as a diazo component. (In the formula, X represents a sulfonic acid group, a sulfamide group, a carboxylic acid group or a carboamide group, and Y represents a hydrogen atom, a sulfonic acid group, a sulfamide group, a carboxylic acid group or a carboamide group.)

[0008]

According to the present invention, when preparing a pigment for a lithographic ink, a pigment composition obtained by using a specific compound as a part of a synthetic component of the pigment is used in a lithographic printing ink to obtain a lithographic printing ink. It was found that the balance of "ink / water" of the lithographic ink was stable and the reproducibility of halftone dots was significantly improved. The lithographic printing ink using the pigment of the present invention specifically includes, for example, (1) easy reproducibility of halftone dots. (2) The time until the emulsification of the ink is stabilized is short, that is, the emulsification speed is high. (3) There are advantages such as suppressing the growth of pigment particles due to heat at the time of flushing during ink production and preventing the ink from becoming opaque.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention is described in more detail with reference to preferred embodiments. The 3,3′-dichlorobenzidine and acetoacetanilide compounds used in the present invention are known, and a part of 3,3′-dichlorobenzidine is substituted by the compound of the formula I, and a mixed tetrazide thereof is obtained. Examples of the acetoacetanilide-based compound that can be coupled include the following compounds.

Acetoacetoanilide, o-chloro-acetoacetoanilide, p-chloroacetoacetoanilide, 4-chloro-2,5-dimethoxyacetoacetoanilide, o-acetoacetoanisidide, o-acetoacetoacetate Toluidide, p-acetoacetotoluidide,
Acetoaceto-m-xylidide, 4-chloro-2-methylacetoacetanilide, p-ethoxyacetoacetoanilide, 4-nitro-2-methylacetoacetoanilide, 4-acetoacetoaminophthalimide, 5-
Acetoacetoaminobenzimidazolone, 4-benzoylamino-2,5-diethoxyacetoacetoanilide and the like.

These acetoacetanilide compounds may be partially mixed with each other and coupled with other acetoacetanilides, and further, a carboxylic acid group, a sulfonic acid group or a carboamide group may be used. Alternatively, an acetoacetanilide compound having a sulfoamide group may be partially used in combination with the above anilide. In particular, the compound of the formula I is used as a part of a diamine in the same manner as described above, and an acetoacetanilide-based compound having a carboxylic acid group or a carboamide group as a coupling component is replaced with a part of the anilide. When introduced, a pigment excellent in transparency, heat resistance during flushing, gloss and the like can be obtained very efficiently.

That is, JP-B-45-11026, JP-B-55-49087, and JP-B-60-36224.
In the examples described in the publication, it is particularly effective to use a tetrazoide of the compound of the formula I as a part of the diazo component. The range of use of the compound of the formula I for 3,3′-dichlorobenzidine is 0.5% of the total diazo component.
%, Preferably 0.5 to 30 mol%.
It is a ratio occupying 4 mol%.

[0013]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the description, parts and% are based on weight unless otherwise specified. Example 1 50.1 parts of 3,3'-dichlorobenzidine and 1,4-
0.75 parts of diaminobenzene-2-sulfonic acid is tetrazotized according to a conventional method to obtain a mixed tetrazonium salt solution. Separately, 70.6 parts of the above-mentioned acetoacetanilide and 4.0 parts of p-acetoacetotoluidide are dissolved and mixed to prepare a mixed marinade. After the two liquids are mixed and coupled, the mixture is filtered and washed with water to obtain a wet press cake. This press cake was used as a lithographic printing ink according to the ink preparation method described below, and then an ink emulsification test was performed.

As a result, as shown in Table 1 below, an ink having an extremely high emulsification rate was obtained as compared with the control pigment to which the technique of the present invention was not applied. Further, when a printing test was performed for each of the inks, a dot (fla
A glossy print having almost no w), a clear outline, and an extremely small dot gain as shown in Table 2 below was obtained.

Example 2 49.6 parts of 3,3'-dichlorobenzidine and 1,4-
1.2 parts of diaminobenzene-2-carboxylic acid is tetrazotized according to a conventional method to obtain a mixed tetrazonium salt solution. On the other hand, 72.1 parts of acetoacetoanilide and 4-chloro-2,5-dimethoxyacetoacetoanilide.
Then, 4 parts are dissolved and mixed to prepare a mixed marinade. After the two liquids are mixed and coupled, the mixture is filtered and washed with water to obtain a wet press cake. This press cake was used as a lithographic printing ink according to the ink preparation method described below, and then an ink emulsification test was performed. As a result, as shown in Table 1 below, compared with the control pigment to which the technology of the present invention was not applied, the emulsification speed was higher, the stability with time was good, and the ink was extremely good in print finish. there were.

Example 3 50.1 parts of 3,3'-dichlorobenzidine and 1,4-
0.75 parts of diaminobenzene-2-sulfonic acid is tetrazotized according to a conventional method to obtain a mixed tetrazonium salt solution. On the other hand, 2,4-acetoacetoxy sulfide 81.8
And 4.0 parts of o-acetoacetotoluidide are dissolved and mixed to prepare a mixed marinade. After mixing and coupling the two solutions, the mixture is filtered and washed with water to obtain a wet press cake. After emulsification using this press cake in the same manner as in Example 1, the obtained ink was subjected to an emulsification test and a printing test. As a result, the ink was extremely good in print finish.

Example 4 50.1 parts of 3,3'-dichlorobenzidine, 0.75 part of 1,4-diaminobenzene-2-sulfonic acid and 3,3
0.25 parts of 3'-dimethoxybenzidine is tetrazotized according to a conventional method to obtain a mixed tetrazonium salt solution.

On the other hand, 85.2 parts of 2,4-acetoacetoxy sulfide and 1.87 parts of acetoaceto-2-carboxyanilide are dissolved and mixed to prepare a mixed marinade.
After the coupling, 6.0 parts of rosin is adsorbed and precipitated on the pigment particles according to a conventional method, and the temperature is raised to 80 ° C., stirred, filtered, washed with water, and dried and pulverized to obtain 140 parts of the powdery pigment of the present invention. After this powdery pigment was converted into an ink, the obtained ink was subjected to an emulsification ratio measurement and a printing test. As a result, it was found that the ink had extremely good print finish.

(Preparation of Ink) Ink of press cake Introduce 300 parts of lithographic ink varnish into the flasher,
The press cake obtained in Examples 1 to 3 was 80% by weight of the pigment.
And kneading at a temperature of 60 ° C. After removing the primary separated water and further removing the secondary separated water under reduced pressure, 420 parts of varnish is added, and an ink is produced through three rolls. still,
In order to compare these inks, control pigments to which the technique of the present invention was not applied were synthesized in the same manner as in the examples, and converted into inks similarly (Comparative Examples 1 to 3).

2. Preparation of powdery pigment as ink 80 parts of powdery pigment of Example 4 and lithographic ink varnish 400
The part is made into ink through three rolls. For comparison, a control pigment to which the technique of the present invention was not applied was synthesized, and was similarly made into an ink (Comparative Example 4).

3. Preparation of Ink The inks of the above 1 and 2 were adjusted to a tack value of 10 to 10.5 with a lithographic varnish and a solvent (incometer, 30 ° C., 1,200 rpm, 20 seconds).

(Emulsification test) The emulsification rate was measured by mixing 100 parts of the ink and 100 parts of the fountain solution with a Duke Mixer. Table 1 shows the results. The dampening water is 1
A 0% isopropyl alcohol aqueous solution was used.

[0023]

[Table 1] Measurement of emulsification rate

(Printing test) Printing was performed on an offset printing machine (Gestetner, Model 211) using a PS plate (screen 10).
0), using the above-mentioned dampening solution and woodfree paper. Observation of the halftone dots and measurement of the area ratio are performed after starting the regular printing for 1,000 hours.
Using the 0th print, the test was performed using beuvac III (manufactured by Toyo Ink) and a densitometer (GRETAG O-142). Note that the measured value of the dot area ratio is based on a solid portion (100% area ratio) of the printed matter. The gloss was measured at this portion with a photometer (60 °).

[0025]

[Table 2]

[0026]

According to the present invention, when preparing a pigment for a lithographic ink, a pigment composition obtained by using a specific compound as a part of a synthetic component of the pigment is used in a lithographic printing ink to obtain a lithographic printing ink. It was found that the balance of "ink / water" of the lithographic ink was stable and the reproducibility of halftone dots was significantly improved. The lithographic printing ink using the pigment of the present invention specifically includes, for example, (1) easy reproducibility of halftone dots. (2) The time until the emulsification of the ink is stabilized is short, that is, the emulsification speed is high. (3) There are advantages such as suppressing the growth of pigment particles due to heat at the time of flushing during ink production and preventing the ink from becoming opaque.

Continuation of the front page (72) Inventor Shojiro Horiguchi 1-7-6, Bakurocho, Nihonbashi, Chuo-ku, Tokyo Inside Dainichi Seika Kogyo Co., Ltd. (56) References JP-A-57-126856 (JP, A) JP-A-61 -200173 (JP, A) JP-A-55-135165 (JP, A) JP-A-54-46225 (JP, A) JP-B-45-11026 (JP, B1) JP-B-47-50767 (JP, B1) (58) Fields surveyed (Int. Cl. ⁶ , DB name) C09B 67/20 C09B 67/22 CA (STN) REGISTRY (STN) WPIDS (STN)

Claims (2)

(57) [Claims] An acetoacetanilide-based compound is used as a coupling component, and a 3,3'-dichloro-benzidine tetrazoide and a diazo tetrazide of the following formula I are coupled as a diazo component. Disazo pigment composition. (In the formula, X represents a sulfonic acid group, a sulfamide group, a carboxylic acid group or a carboamide group, and Y represents a hydrogen atom, a sulfonic acid group, a sulfamide group, a carboxylic acid group or a carboamide group.) 2. The disazo pigment composition according to claim 1, wherein 0.2 to 30 mol% of the total diazo component is a tetrazoide of the compound of the formula I.