JPH05262999A - Disazo compound - Google Patents

Abstract

PURPOSE:To provide the subject new pigment resistive to thermal decomposition even in a remarkably sever condition of high temperatures, excellent in heat resistance when used as a pigment in a resin and useful as a printing ink, plastic colorant, coating material, printing agent, etc. CONSTITUTION:A compound of formula I. This compound is obtained recommendably by reacting dichlorobenzidin of formula II with sodium nitrite in the presence of a hydrochloric acid salt at 0 to 10 deg.C and subsequently reacting the resultant tetrazotized compound with a coupler component prepared by dissolving barbituric acid of formula III in water and adjusting its pH to 5 to 6 according to a method in which the tetrazotized compound is added dropwise to the coupler component at 15 to 20 deg.C. In addition, the resultant disazo pigment is preferably treated in an amide-based solvent such as formamide at >=100 deg.C and <= the boiling point of the amide-based solvent since the clearness, the tinting strength and the light resistance can be remarkably improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel disazo pigment which is excellent in heat resistance and is suitable for printing inks, plastic colorants, paints, printing agents and the like.

[0002]

2. Description of the Related Art Disazo pigments have excellent coloring power, vividness,
It is the most excellent pigment for printing inks because of its relatively low price.

However, when used for applications such as plastic colorants and paints, the heat resistance is not sufficient, and in order to improve this point, the following structural formula (2) structural formula (2)

[0004]

[Chemical 4]

C. represented by I. Pigment Yellow 8
No. 3 is known as a disazo pigment excellent in heat resistance.

[0006]

However, the above C. I.
Pigment Yellow 83, when used in engineering plastics such as polyamide and polycarbonate, and in general plastic materials such as polyethylene, polypropylene and ABS resin at temperatures exceeding 250 ° C. It has a problem that it is easily decomposed by heat and causes discoloration.

The problem to be solved by the present invention is to provide a disazo pigment which is not easily decomposed by heat even under extremely severe high temperature conditions and which has excellent heat resistance of the resin when used as a coloring agent in the resin. It is in.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have solved the above problems by using a disazo pigment represented by the following structural formula (1). After finding out the above, the present invention has been completed.

That is, the present invention relates to a disazo pigment represented by the following structural formula (1). Structural formula (1)

[0010]

[Chemical 5]

The disazo pigment of the present invention can be manufactured as follows. That is, sodium nitrite is reacted with dichlorobenzidine represented by the following structural formula (3) at 10 to 0 ° C. in the presence of hydrochloride to form tetrazo. Structural formula (3)

[0012]

[Chemical 6]

Next, this tetrazodide and barbituric acid represented by the following structural formula (4) are dissolved in water to obtain PH3.
To 7, preferably PH 5 to 6, and a coupler component prepared by a coupling reaction. This coupling reaction is carried out by continuously or intermittently dropping the tetrazo compound in the temperature range of 15 to 20 ° C. from the viewpoint that the coupler component becomes 10 to 30 ° C. and the hue of the pigment becomes more vivid. . Structural formula (4)

[0014]

[Chemical 7]

The thus-obtained disazo pigment of the present invention represented by the above structural formula (1) is usually crystallized by X-ray diffraction analysis shown in FIG. 1 unless special treatment is applied after purification. As shown in the figure (hereinafter, this crystal form is referred to as α type), the powder or aqueous paste of this α type disazo pigment is treated in an amide solvent at 50 ° C. or higher, preferably 100 ° C.
By performing the treatment above the boiling point of the amide solvent, the sharpness, the coloring power and the light resistance can be remarkably improved.

The crystal form of the disazo pigment thus obtained by treatment with an amide-based solvent is as shown in FIG. 2 in the X-ray diffraction pattern, the diffraction angle (2θ ± 0.2 °; Cu-K).
α) has the strongest diffraction strength at 28.4 °, the next highest diffraction strength at 13.3 °, and the weaker diffraction strengths at 10.6 ° and 16.2 °. (Hereinafter, this crystal type is referred to as β type).

Examples of the amide-based polar solvent used in the present invention include formamide, dimethylformamide, dimethylacetamide, diethylformamide, N-methyl-2-pyrrolidone and hexamethylenephosphamide.

The disazo pigment thus obtained, regardless of whether its crystal form is α-type or β-type, has a strong hydrogen bond between hydrogen atoms and oxygen atoms in the molecular structure, resulting in a large crystal as a whole. Since it behaves as a molecule, it has extremely excellent heat resistance. Therefore, it can be used as a colorant in various resins, for example, vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, polyvinyl alcohol, polyvinyl acetal, polystyrene,
AS resin, ABS resin, methacrylic resin, polyethylene, polypropylene, fluororesin, polyamide, polyacetal, polycarbonate, polysulfone, celluloid, acetic acid fiber plastic, polyethylene terephthalate, thermoplastic resin, phenol resin, urea resin,
Examples thereof include melamine resin, furan resin, alkyd resin, unsaturated polyester, diallyl phthalate resin, epoxy resin, silicone resin, polyurethane, and thermosetting resin. Among them, vinyl chloride resin, vinylidene chloride resin, polypropylene, polyethylene, and polyethylene terephthalate are preferable because they have excellent dispersibility of the pigment and excellent color development of the resin.

[0019]

EXAMPLES Examples, comparative examples and test examples are given below,
The present invention will be described in more detail, but the present invention is not limited thereto. Various tests were conducted in the following manner, and parts and% in Examples and Comparative Examples are based on weight.

(Thermogravimetric analysis and differential thermal analysis) Thermogravimetric analysis and differential thermal analysis were carried out using a thermal analysis system TA-50 manufactured by Shimadzu Corporation. Α-Alumina was used as the standard substance, the temperature rising rate was kept constant at 10 ° C./min, and the test was performed in a nitrogen atmosphere. The sampling amount was 10 mg.

(Heat resistance test) A dry color consisting of 3 parts of the pigment and 3 parts of zinc stearate obtained in each Example and Comparative Example was blended with 1000 parts of polypropylene, and a 3 ounce in-line screw type injection molding machine was used. Molding temperature 220 ° C, residence time 10 minutes, 250 ° C 10 minutes, 2
A flat plate was formed under the conditions of 80 ° C for 10 minutes, and three dyes (△
E) was measured and the heat resistance was evaluated. The result is first
Shown in the table.

(Plastic Coloring Test) A dry color composed of 3 parts of the pigment and 3 parts of zinc stearate obtained in each Example and Comparative Example was blended with 1000 parts of polypropylene, and a 3 oz in-line screw type injection molding machine was used. A flat plate was prepared under the conditions of a molding temperature of 220 ° C. and a residence time of 10 minutes, and the chroma (C *) was measured by a spectrophotometric method. The results are shown in Table 2.

(Lightfastness test) 4.0 parts of the pigment obtained in each of the examples and comparative examples and 16.0 of a rosin-modified phenolic resin
The part was kneaded with a Hoover type muller three times at 100 revolutions to prepare an ink paste, which was spread on a test paper. These are accelerated light resistance test 60, 9 by UV carbon arc lamp.
Three dyes (△ E *) over 0, 120 and 150 hours
Was measured and the light resistance was evaluated. The results are shown in Table 3.

Example 1 16.4 parts of 3,3'-dichlorobenzidine hydrochloride was added to 2 parts.
After dispersing in 35.6 parts of 0% hydrochloric acid, add 500 parts of water and
31.1 parts of 30% sodium nitrite is added while maintaining
Tetrazo was converted to a tetrazo solution.

Next, 18.1 parts of barbituric acid was dissolved in 500 parts of water at 80 ° C., and 3.6 parts of 90% acetic acid was added.
Then, cool to 15 ° C and adjust the pH with a 5% aqueous sodium hydroxide solution.
The coupler solution was adjusted to 5.5 to obtain a coupler solution.

2 parts of the above tetrazo solution was added to this coupler solution.
The mixture was dropped over a period of time to carry out a coupling reaction. After completion of the coupling reaction, the pH was adjusted to 6.0 with a 5% aqueous sodium hydroxide solution, the liquid temperature was raised to 90 ° C., the mixture was heated with stirring for 1 hour, filtered, washed with water, and dried at 90 ° C. to obtain a disazo pigment.

As shown in FIG. 1, this pigment has a diffraction angle (2θ ± 0.2 °; Cu-Kα) 2 in an X-ray diffraction pattern.
It had a strong diffraction intensity at 6.7 °, a medium diffraction intensity at 12.4 °, and a relatively weak diffraction intensity at 17.7 °. The infrared absorption spectrum of this pigment is shown in FIG.

Using this pigment, various tests such as a pigment thermal characteristic test, a heat resistance test, a plastic coloring test and a light resistance test were conducted. Figure 6 shows the results of the pigment thermal characteristics test, Table 1 shows the results of the heat resistance test, and Table 2 shows the results of the plastic coloring test.
The results of the table and the light resistance test are shown in Table 3.

Example 2 35.4 parts of the disazo pigment obtained in the same manner as in Example 1 was put together with 350 parts of dimethylformamide in a closed container equipped with a stirrer, the temperature was raised to 140 ° C. in 60 minutes, and 4 After stirring for an hour, it is cooled to 60 ° C., filtered, washed with water,
After drying at ° C, the disazo pigment of the present invention was obtained.

As shown in FIG. 3, this pigment has a diffraction angle (2θ ± 0.2 °; Cu-Kα) 2 in the X-ray diffraction pattern.
It has the strongest diffraction strength at 8.4 °, the next highest diffraction strength at 13.3 °, and the weaker diffraction strength at 1 °.
It was at 0.6 ° and 16.2 °. The infrared absorption spectrum of this pigment is shown in FIG.

Using this pigment, a pigment thermal characteristic test, a heat resistance test, a plastic coloring test and a light resistance test were conducted.
The results of the pigment thermal property test are shown in FIG. 7, the heat resistance test results are shown in Table 1, the plastic coloring test results are shown in Table 2, and the light resistance test results are shown in Table 3.

Example 3 The aqueous paste of disazo pigment obtained by carrying out the coupling reaction in the same manner as in Example 1 was put together with 500 parts of diethylformamide in a closed container equipped with a stirrer and heated to 150 ° C. in 60 minutes. After stirring for 3 hours as it was, the mixture was cooled to 60 ° C., filtered, washed with water, and dried at 90 ° C. to obtain 35.4 parts of a disazo pigment.

In the X-ray diffraction pattern, this pigment had almost the same diffraction intensity at the same diffraction angle as in Example 1. Using this pigment, heat resistance test, plastic coloring test and light resistance test were conducted. The results of the heat resistance test are shown in Table 1, the results of the plastic coloring test are shown in Table 2, and the results of the light resistance test are shown in Table 3.

Comparative Example 1 A tetrazo solution was obtained in the same manner as in Example. Then acetoaceto-2,5-dimethoxy-4-chloroanilide 38.3
After being dispersed in 500 parts of water at 20 ° C., 41.4 parts of a 25% aqueous sodium hydroxide solution was added and dissolved. Furthermore, add 2 to this solution.
A coupler solution was obtained by dropping 80 parts of 0% acetic acid.

2 parts of the above tetrazo solution was added to this coupler solution.
The mixture was dropped over a period of time to carry out a coupling reaction. After completion of the coupling reaction, the pH was adjusted to 6.0 with a 5% aqueous sodium hydroxide solution, the liquid temperature was raised to 90 ° C., the mixture was heated with stirring for 1 hour, filtered, washed with water, and dried at 90 ° C. to obtain a disazo pigment.

This pigment is C.I. I. Pigment Yellow 8
3, which is an existing disazo pigment known to have good heat resistance. The infrared absorption spectrum of this pigment is shown in FIG. Using this pigment, a pigment thermal characteristic test and a heat resistance test were conducted. The results of the pigment thermal characteristics test are shown in FIG. 8, and the results of the heat resistance test are shown in Table 1.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

EFFECTS OF THE INVENTION According to the present invention, there can be provided a disazo pigment which is not easily thermally decomposed under extremely severe high temperature conditions and which has excellent heat resistance of the resin when used as a coloring agent in the resin.

[Brief description of drawings]

FIG. 1 is an X-ray diffraction diagram (2θ ± 0.2 °; Cu-Kα) of the disazo pigment of the present invention obtained in Example 1.

FIG. 2 is an infrared absorption spectrum diagram of the disazo pigment of the present invention obtained in Example 1.

FIG. 3 is an X-ray diffraction diagram (2θ ± 0.2 °; Cu-Kα) of the disazo pigment of the present invention obtained in Example 2.

FIG. 4 is an infrared absorption spectrum chart of the disazo pigment of the present invention obtained in Example 2.

FIG. 5 shows the C.I. I. It is an infrared absorption spectrum diagram of Pigment Yellow 83.

FIG. 6 is a diagram showing the results of thermogravimetric analysis and differential thermal analysis of the disazo pigment of the present invention obtained in Example 1. a ₁ : Calorimetric analysis curve b ₁ : Differential thermal analysis curve

FIG. 7 is a view showing the results of thermogravimetric analysis and differential thermal analysis of the disazo pigment of the present invention obtained in Example 2. a ₂ : Calorimetric analysis curve b ₂ : Differential thermal analysis curve

FIG. 8 shows C.I. obtained in Comparative Example 12. I. FIG. 3 is a diagram showing the results of thermogravimetric analysis and differential thermal analysis of the disazo pigment of the present invention of Pigment Yellow 83. a ₃ : Calorimetric analysis curve b ₃ : Differential thermal analysis curve

Claims (3)

[Claims] 1. A disazo pigment represented by the following structural formula (1). Structural formula (1) 2. The structure is represented by the following structural formula (1), and the crystal has a diffraction angle (2θ ± 0.2 °;
Cu-Kα) has the strongest diffraction strength at 28.4 °, the next strongest diffraction strength at 13.3 °, and the weaker diffraction strengths at 10.6 ° and 16.2 °. The disazo pigment according to claim 1, which is contained in Structural formula (1) 3. The disazo pigment according to claim 2, which is obtained by treating a disazo pigment represented by the following structural formula (1) in an amide solvent at 50 ° C. or higher and at a boiling point of the solvent or lower. Structural formula (1)