JPH08269347A - Production of azo pigment - Google Patents

Abstract

PURPOSE: To enable to easily obtain an azo pigment excellent in colorability and dispersibility and useful for coatings, etc., by subjecting diazotized anthranilic acid to a coupling reaction with an acetoacetylaminobenzimidazolone, and subsequently thermally treating the reaction product under specific conditions. CONSTITUTION: This method for producing an azo pigment comprises subjecting diazotized anthranilic acid to a coupling reaction with 5-acetoacetylamino- benzimidazolone, thermally treating the coupling reaction product in the presence of an alkali (preferably used in a molar ratio of 0.1-0.4 to the coupling reaction product), filtering the treated product, washing the obtained solid product, dissolving the product in an acid (preferably acidified to a pH of 2.0-6.5), and subsequently thermally treating the obtained acidic aqueous solution.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an azo pigment.

[0002]

[Prior Art] Expression

[0003]

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As a method for converting the azo compound represented by the formula (1) into a pigment form, for example, (1) JP-B-47-30412 discloses that a crude pigment obtained by coupling in an aqueous medium is isolated and dried. , Pulverization, heating under reflux in glacial acetic acid, filtration, washing and drying. The pigments obtained in this way are described as soft particles, having good tinting strength and clear shades.

Further, in (2) Japanese Patent Publication No. 3-66351, coupling is carried out in an aqueous medium in the presence of an oxyethylated product of a long-chain alcohol, and an aqueous pigment suspension is prepared after completion of the coupling. It is stated that upon heating, a valuable pigmentary form of this azo compound is obtained.

[0006]

However, in the case of the above method (1), since the crude pigment is dried and crushed and glacial acetic acid is used in order to obtain the pigment form, the operation is complicated. Moreover, there is a drawback that the manufacturing cost becomes high.

Further, in the case of the above method (2), although the operation is simple, ethylene oxide and the alcohol reactant are adsorbed on the surface of the pigment because ethylene oxide and the alcohol reactant are added for coupling. When the surface state of the pigment is changed and the pigment is made into a coating material, blisters and the like may occur.

[0008] The problem to be solved by the present invention is to provide a method for obtaining a pigment form in water only with an acid and an alkali, without using a special pigmenting solvent and without using additives. It is in.

[0009]

SUMMARY OF THE INVENTION The present inventors have completed the present invention as a result of earnest research to solve the drawbacks of the prior art in view of these circumstances.

That is, in order to solve the above-mentioned problems, the present invention provides a compound of the formula: diazotized anthranilic acid by a coupling reaction with 5-acetoacetylamino-benzimidazolone, followed by thermal post-treatment.

[0011]

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In the method for producing an azo pigment, the pigment form of the azo compound represented by

The thermal post-treatment includes (1) a first step in which the coupling reaction product is heat-treated with an alkali, and (2) a heat treatment in which the alkali heat-treated product is filtered and washed, and then made into an acidic aqueous solution. Provided is a method for producing an azo pigment, which comprises two steps.

Next, the present invention will be described in detail.

The coupling reaction of diazotized anthranilic acid with 5-acetoacetylamino-benzimidazolone is carried out according to conventional methods, for example in acetic acid-sodium acetate buffered aqueous medium.

The coupling reaction product is obtained in the first stage by
After making the alkali weak, the carboxylic acid of the azo compound is partially converted to a sodium carboxylic acid salt by heating in an alkaline state.

Examples of the alkali to be added after the completion of the coupling reaction include sodium hydroxide aqueous solution and potassium hydroxide aqueous solution.

The amount of alkali added after the completion of the coupling reaction is preferably an amount that makes the coupling reaction product a weak alkali. Specifically, 0.05 to 0.6 mol relative to the coupling reaction product. A ratio range is preferred and 0.
A range of 1 to 0.4 molar ratio is particularly preferred.

After the coupling reaction product is weakly alkaline, the heating temperature is preferably in the range of 60 to 100 ° C.

The coupling reaction product is heated in an alkaline state, then filtered and washed to obtain a wet crude pigment.
By filtering and washing in this state, unreacted 5-acetoacetylamino-benzimidazolone and by-produced salts can be removed. Incidentally, the sodium salt of carboxylic acid of azo compound does not dissolve.

In the second step, the crude pigment wet obtained in the first step is redispersed in water, and then a mineral acid or an organic acid is added to make an acidic aqueous solution, and then heat treatment is performed.

Examples of the mineral acid or organic acid include hydrochloric acid, acetic acid and the like.

The addition amount of the mineral acid or organic acid used in the second step is preferably such that the pH of the acidic aqueous solution is in the range of 2.0 to 6.5.

The heating temperature in the second stage is 60
The range of 150 to 150 ° C is preferable, and the range of 90 to 98 ° C is particularly preferable. The heating time is preferably in the range of 1 to 8 hours, particularly preferably in the range of 3 to 5 hours.

What should be noted here is that the azo compound is completely converted to a carboxylic acid. Since the sodium salt of carboxylic acid of azo compound has a function of a kind of buffer solution and the suspension, the rate of conversion of sodium carboxylate into carboxylic acid is slow, and the pH also changes. Is important to adjust to 2.0 to 6.5.

As described above, the pigment form is adjusted with acid and alkali in water without using a special pigment-forming solvent and without using ethylene oxide and an alcohol reaction product which may change the surface condition of the pigment. Obtainable.

The pigment obtained in the present invention has a good coloring power,
It is a greenish yellow pigment with high hiding power, good dispersibility, high gloss, and good weather resistance.

The pigment form is adjusted in this way, the suspension is filtered, washed and dried.

The pigment obtained by the present invention is suitable for coloring various plastics, paints, printing inks, rubber, leather, pigment printing and the like.

[0030]

EXAMPLES Next, the present invention will be specifically described with reference to Examples, Reference Examples and Comparative Examples. In the following, all "parts" and "%" are based on weight unless otherwise specified.

(Example 1) 47 parts of anthranilic acid was added to 3 parts of water.
After stirring with 00 parts and 188 parts of 20% hydrochloric acid and cooling to 5 ° C. or lower, 87 parts of 30% aqueous sodium nitrite solution was added to diazotize. Excess nitrous acid was decomposed with sulfamic acid to prepare a diazo solution.

84 parts of 5-acetoacetylamino-benzimidazolone, 600 parts of water and 48% of water at 20-25 ° C.
It was dissolved in a mixture with 74 parts of an aqueous sodium hydroxide solution, and 57 parts of 20% acetic acid was added dropwise with stirring to prepare a coupler suspension.

Coupling was carried out by injecting the above diazo solution into the coupler suspension while maintaining the pH of the coupler suspension in the range of 6.5 to 7.0 by appropriately adding 5% sodium hydroxide. The reaction was carried out.

After completion of the coupling reaction, the reaction mixture was charged with 2
After adding 20 parts of 0% sodium hydroxide, the mixture was heated at 80 ° C. for 2 hours. Then, the reaction mixture was filtered and washed to obtain a wet crude pigment. Wet this crude pigment with water 40
Disperse into 100 parts, adjust the pH to 3.5 with hydrochloric acid, and 90 ° C
After heating for 6 hours, it was collected by filtration, washed and dried to obtain a greenish yellow azo pigment.

(Example 2) 47 parts of anthranilic acid was added to 3 parts of water.
After stirring with 00 parts and 188 parts of 20% hydrochloric acid and cooling to 5 ° C. or lower, 87 parts of 30% aqueous sodium nitrite solution was added to diazotize. Excess nitrous acid was decomposed with sulfamic acid to prepare a diazo solution.

84 parts of 5-acetoacetylamino-benzimidazolone, 600 parts of water and 48% of water at 20-25 ° C.
It was dissolved in a mixture with 74.4 parts of an aqueous sodium hydroxide solution, and this solution was added dropwise to a solution consisting of 1500 parts of water and 13 parts of 90% acetic acid to prepare a coupler suspension.

Coupling was performed by injecting the above diazo solution into the coupler suspension while maintaining the pH of the coupler suspension in the range of 6.5 to 7.0 by appropriately adding 5% sodium hydroxide. The reaction was carried out.

After the completion of the coupling reaction, acetic acid was added to the reaction mixture to neutralize it so that the amount of alkali was 0.3 mol ratio, and then the mixture was heated at 90 ° C. for 3 hours. Then, the reaction mixture was filtered and washed to obtain a crude pigment wet. Disperse the wet wet of this crude pigment in 4000 parts of water and adjust the pH with acetic acid.
Was adjusted to 5.5 and heated at 95 ° C for 4 hours, then filtered
It was washed and dried to obtain a greenish yellow azo pigment.

(Comparative Example) 13.7 g of anthranilic acid was added to
Stir with 250 ml of water and 50 ml of 5N hydrochloric acid,
20 ml of N sodium nitrite solution was added for diazotization.

24 g of 5-acetoacetylamino-benzimidazolone was stirred with 200 ml of water at room temperature to give 5N.
60 ml of an aqueous sodium hydroxide solution was added and dissolved.
The solution was clarified with activated carbon and the filtrate was stirred for 30 minutes with 30 ml of water, 41 ml of glacial acetic acid, 80 ml of 5N aqueous sodium hydroxide solution and 1 mol of an industrial alcohol fraction having 9 to 11 carbon atoms and ethylene oxide. It was added dropwise to a solution consisting of 3 g of a reaction product with 5 mol to obtain an acetic acid acidic suspension of a coupling component.

While stirring the acetic acid acidic suspension of the coupling component, the diazo solution was added dropwise thereto at 25 ° C.

After the coupling was completed, the suspension was mixed with 95-
Heated to 97 ° C. for 3 hours. After filtering the suspension at 60 to 70 ° C., the presscake was washed until it was free of salt, and then dried to obtain a pale yellow azo pigment.

<Preparation of Melamine Alkyd Baking Paint> (Preparation of Color Enamel) 4.0 g of any pigment obtained in each Example and Comparative Example, alkyd resin (“Beckosol J-524 manufactured by Dainippon Ink and Chemicals, Inc.”) -IM-60 ")
16.0 g, xylene 75% and n-butanol 25%
10.0g mixed solvent consisting of and glass beads (3mm
φ) 80 g was put in a glass bottle having a capacity of 100 ml and dispersed with a paint conditioner for 1 hour, and then alkyd resin (Dainippon Ink and Chemicals Co., Ltd. “Beckosol J-
524-IM-60 ") and 30.2 g of melamine (manufactured by Dainippon Ink and Chemicals, Inc.," Super Beckamine L-11 ").
7-60 ") 19.8 g was added and dispersed for 10 minutes with a paint conditioner to obtain a colored enamel.

(Preparation of white enamel) 24.0 g of titanium white ("Taipec R-930" manufactured by Ishihara Sangyo Co., Ltd.), 24.0 g of alkyd resin ("Beckosol J-524-IM- manufactured by Dainippon Ink and Chemicals, Inc." 60 "), xylene 75
% And n-butanol 25% mixed solvent 4.8 g
And glass beads (3mmφ) 80.0g capacity 500m
It was placed in a glass bottle of 1 l and dispersed for 1 hour with a paint conditioner, and then alkyd resin (“Beckosol J-524-IM-60” manufactured by Dainippon Ink and Chemicals, Inc.) 1
1.8 g and 15.4 g of melamine ("Super Beckamine L-117-60" manufactured by Dainippon Ink and Chemicals, Inc.)
Was added and mixed with a paint conditioner for another 10 minutes to obtain white enamel.

<< Test Method for Paint >> <Evaluation of Dispersibility of Paint> Evaluation Method: The dispersed paint was evaluated with a crush gauge.

The evaluation criteria are as follows. ◯: 10 μm or less Δ: 10 to 20 μm ×: 20 μm or more

<Evaluation of tinting strength> Evaluation method: White diluted paint (6 g of colored enamel and 1 of white enamel)
0 g of the mixture) was applied onto art paper using an applicator to a wet film thickness of 150 μm, and then 13
Baking at 0 ° C. for 20 minutes. The color of the test piece is measured with a spectrophotometer, and the standard pigment (Hostaper manufactured by Hoechst Co.)
The coloring power when the coloring power of m Yellow H4G) was set to 100 was calculated.

The evaluation criteria are as follows. ○: 98% or more △: 95 to 98% ×: 95% or less

<Evaluation of Concealment Power> The color enamel was coated on a concealment test paper with an applicator to obtain a wet film thickness of 250 μm.
After being applied so as to have the following composition, it was baked at 130 ° C. for 20 minutes.

The evaluation method is as follows: Lightness Lb of black background
And the brightness Lw of the white background were measured and calculated by the ratio of Lb / Lw.

The evaluation criteria are as follows. ◯: Lb / Lw is 0.90 or more Δ: Lb / Lw is 0.85 to 0.90 x: Lb / Lw is 0.85 or less

<Bleed resistance test> A mixed solvent consisting of 40 parts of "Solvesso # 100", 30 parts of xylene, 20 parts of n-butanol, and 10 parts of cellosolve acetate was added to the colored enamel, and Ford cup No. A colored coating material was prepared so that the viscosity according to No. 4 was adjusted to 21 seconds.

On a 150 × 70 mm water-polished dull steel plate (manufactured by Nippon Test Panel Co., Ltd.), the above paint was applied by using a spray gun so that the film thickness after drying was 25 to 30 μm. After leaving the coated steel plate at room temperature for 1 hour,
It was baked and dried in a drier at 140 ° C. for 30 minutes to obtain a colored coated plate. This colored coated plate is also used in the water resistance test described below.

[Solvesso # 100] 4 on white enamel
A mixed solvent consisting of 0 part, 30 parts of xylene, 20 parts of n-butanol and 10 parts of cellosolve acetate was added, and Ford cup No. A white paint was prepared so that the viscosity according to No. 4 was adjusted to 21 seconds.

The white paint was applied to the colored coated plate by using a spella gun until the color of the coated plate was completely covered. At that time, as a standard coated plate for comparison, the above white paint was simultaneously spray-coated on a dull steel plate (manufactured by Japan Test Panel Co., Ltd.) that had been water-polished with intermediate coating. After leaving these coated plates at room temperature for 1 hour, dry them in a dryer at 140 ° C for 3 hours.
The coated plate was obtained by baking and drying for 0 minutes.

Bleed was evaluated by comparing a coated plate having a white coating on the colored coating with a standard plate, and the results are shown in Table 1.
Are summarized in.

The evaluation criteria were as follows by measuring the color difference ΔE from the standard plate and from the color difference. ◯: Color difference ΔE 0.8 or less Δ: Color difference ΔE 0.8 to 1.5 ×: Color difference ΔE 1.5 or more

<Water resistance test> A colored coated plate prepared in the same manner as in the bleed resistance test was protected with a polyester adhesive tape. Put this coated plate in a constant temperature water bath at 50 ℃.
After soaking for a day, the state of the coating film on the surface was observed, and the observation results are summarized in Table 1.

The evaluation criteria are as follows. ○: No blisters (blister) are seen on the painted surface. Δ: A little blister (blister) is seen on the coated surface.

X: A blister (blister) is seen on the coated surface.

[0061]

[Table 1]

From the results shown in Table 1, the pigments obtained in Examples have good dispersibility and coloring power, high hiding power, and excellent bleeding resistance and water resistance when used in melamine alkyd baking paints. It is clear that In contrast,
When using the pigment obtained in Comparative Example, dispersibility, hiding property is slightly inferior, blister occurs in the water resistance test,
Clearly not suitable for melamine alkyd baking paints.

<< Testing Method for Lithographic Ink >> (Preparation of Dark Ink) 0.6 g of any pigment and varnish (Dainippon Ink and Chemicals) obtained in each Example and Comparative Example
1.5 mg of "MG-63" manufactured by Co., Ltd.) was dispersed using a Hoover Mahler by repeating a load of 150 pounds and 100 rotations three times to prepare an ink.

(Preparation of light color ink) Dark color ink 0.11
g, titanium white (R-550 manufactured by Ishihara Sangyo Co., Ltd.) 1.5 g, and varnish 1.1 g using a Hoover Mahler load 15
The ink was prepared by dispersing 0 pounds and 100 revolutions twice.

<Evaluation of dispersibility of planographic ink> Evaluation method: The size and number of coarse particles of the ink were observed with an optical microscope.

The evaluation criteria are as follows. ◯: No coarse particles are seen. Δ: Some coarse particles are seen.

X: There are many coarse particles.

<Evaluation of tinting strength> Evaluation method: A light-colored ink was drawn on a spreading paper with a spatula to prepare a standard pigment (Hostaperm Yellow H from Hoechst Co.).
4G) and the relative density.

The evaluation criteria are as follows. ◯: Equal to or higher than standard. Δ: Slightly inferior to standard.

X: Clearly inferior to the standard.

<Evaluation of hiding power> Evaluation method: A dark ink was drawn on a spreading paper with a black band with a spatula, and the hiding property at the black band was visually compared with a standard pigment (Hostaperm Yellow H4G from Hoechst). It was judged.

The evaluation criteria are as follows. ◯: Concealability equal to or higher than standard. Δ: Slightly inferior to standard.

X: Clearly inferior to the standard.

[0074]

[Table 2]

From the results shown in Table 2, it is clear that the pigments obtained in Examples have good dispersibility and coloring power and high hiding power when used in planographic ink. On the other hand, when the pigments obtained in Comparative Examples are used, the dispersibility and hiding property are slightly inferior, and it is clear that they are not suitable for lithographic ink.

<< Vinyl Chloride Test Method >> (Preparation of Specimen) 1.0 g of any of the pigments obtained in each Example and Comparative Example and 1.5 g of dioctyl phthalate were used at a load of 150 pounds and 100 revolutions using a Hoover Mahler. Was repeated 3 times for dispersion to obtain a vinyl chloride toner.

Next, 0.5 part of this vinyl chloride toner, 4.0 parts of vinyl chloride white masterbatch (manufactured by Dainippon Ink and Chemicals, Inc.) and vinyl chloride compound ("Binica compound C982 clear" manufactured by Mitsubishi Kasei Vinyl Co., Ltd.) 1
Milling of 00 parts was carried out for 3 minutes at 150 ° C. using a heated two-roll to prepare a vinyl chloride crude sheet having a pigment content of 0.2% and a pigment / titanium dioxide ratio of 1:10. The rough sheet was pressed with a hot press for 3 minutes to produce a vinyl chloride sheet.

<Evaluation of tinting strength> Evaluation method: Standard pigment (Hostaperm manufactured by Hoechst Co.)
(Yellow H4G) was visually evaluated.

The evaluation criteria are as follows. ◯: Equal to or higher than standard. Δ: Slightly inferior to standard.

X: Clearly inferior to the standard.

<Evaluation of heat resistance> Evaluation method: Put in an oven at 175 ° C. for 30 minutes, and measure the degree of color change.

The evaluation criteria are as follows. ◯: Color difference ΔE1.5 or less Δ: Color difference ΔE1.5 to 3.0 ×: Color difference ΔE3.0 or more

[0083]

[Table 3]

From the results shown in Table 3, it is apparent that the pigments obtained in Examples have good tinting strength and excellent heat resistance when applied to the coloring of vinyl chloride sheets. On the other hand, even when using the pigment obtained in Comparative Example, the coloring power,
It is clear that the heat resistance is excellent.

[0085]

EFFECTS OF THE INVENTION According to the present invention, a greenish yellow azo pigment can be easily produced in water using only an acid and an alkali without using a special pigmenting solvent and without using additives. The pigment obtained by the production method of the present invention is
(1) A paint having good coloring power and dispersibility, high hiding power, and excellent bleeding resistance and water resistance, (2) Ink having good dispersibility and coloring power, and high hiding power, (3) Dispersion It is possible to provide a colored resin having excellent heat resistance and heat resistance.

[Procedure amendment]

[Submission date] April 11, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction content]

After the coupling was completed, the suspension was mixed with 95-
Heated to 97 ° C. for 3 hours. After filtering the suspension at 60 to 70 ° C., the presscake was washed until it was free of salt and then dried to obtain a greenish yellow azo pigment.

Claims (7)

[Claims] 1. A diazotized anthranilic acid is subjected to a coupling reaction with 5-acetoacetylamino-benzimidazolone, followed by a thermal aftertreatment to give a compound of formula In the method for producing an azo pigment to obtain a pigment form of an azo compound represented by the formula (1), the thermal post-treatment comprises (1) a first step in which the coupling reaction product is heat-treated with an alkali, and (2) an alkali heat-treated product is filtered and washed. After that, the method for producing an azo pigment is characterized by comprising the second step of heat treatment after being made into an acidic aqueous solution. 2. The amount of alkali used in the first stage of thermal post-treatment is from 0.05 to 0.5 based on the coupling reaction product.
The method for producing an azo pigment according to claim 1, wherein the azo pigment has a molar ratio in the range of 0.6. 3. The amount of alkali used in the first stage of thermal aftertreatment is 0.1 to 0.
The method for producing an azo pigment according to claim 1, wherein the ratio is in the range of 4 molar ratio. 4. The method for producing an azo pigment according to claim 1, 2 or 3, wherein the pH of the acidic aqueous solution used in the second stage of the thermal post-treatment is in the range of 2.0 to 6.5. 5. The process for producing an azo pigment according to claim 1, 2, 3 or 4, wherein the first step of the heat treatment is heat treatment in the range of 60 to 100 ° C. 6. The method for producing an azo pigment according to claim 1, wherein the second step of thermal post-treatment is heat treatment in the range of 60 to 150 ° C. 7. The method for producing an azo pigment according to claim 1, wherein the second step of thermal post-treatment is heat treatment in the range of 80 to 98 ° C.