JP2002146224A - Quinacridone solid solution pigment and method for producing the same - Google Patents

Abstract

(57) [Summary] [Problem] To obtain a quinacridone pigment excellent in transparency compared to the conventional method by a simpler method than the conventional method. SOLUTION: The unsubstituted quinacridone is heated by heating a crude quinacridone solid solution pigment containing unsubstituted quinacridone and 4,11-dichloroquinacridone as essential components in a liquid medium in excess of the crude quinacridone solid solution pigment. And 4,11-dichloroquinacridone as essential components, and a CuKα characteristic X-ray (wavelength 1.54
1A; Angstrom), the Bragg angle (2θ ± 0.2 °) in the powder X-ray diffraction diagram was 26.7 °, 13.
In a quinacridone solid solution pigment having peaks at 3 ° and 6.4 °, the respective peak intensities are 5,000 to 75.
00 cps, 2100-6500 cps, 2000-5
A quinacridone solid solution pigment of 000 cps is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a quinacridone solid solution pigment excellent in transparency and its production in finely divided pigments used in the fields of paints, printing inks, ink jets, writing instruments, color filters, etc., which require transparency. It is about the method.

[0002]

2. Description of the Related Art Since finely divided pigments have high transparency, they have been used in metallic paints and mica paints for automobiles and candy tone inks in metal inks. More recently, demands for inkjet inks, writing instruments, color filters, and the like have increased, and there has been a high demand for finely divided pigments.

[0003] Micronized pigments are usually produced by making the crude pigment finer or by growing the preliminarily pulverized amorphous pigment in a crystal form. Heretofore, quinacridone-based pigments have been mainly used for applications requiring hiding properties, such as general-purpose paints, and methods for producing finely divided pigments have not been well known. The quinacridone pigment is a slightly bluish red pigment, but there is a so-called solid solution pigment composed of two or more kinds of quinacridone compounds having different chemical structures, and the color gamut of the quinacridone pigment is expanded. These solid solution pigments are characterized by a powder X-ray diffraction pattern.

Under such circumstances, as a method for producing a finely divided pigment in a solid solution pigment of unsubstituted quinacridone and 4,11-dichloroquinacridone as described in the present invention, for example, JP-A-60-35055 and US Pat. 3rd, 60th
7,336 and JP-A-9-176507.

JP-A-60-35055 describes a method in which two or more kinds of quinacridones having different chemical structures are dissolved in an aprotic polar organic solvent in the presence of a caustic alkali and neutralized and reprecipitated with an acid. Have been. However, in order to obtain a finely divided pigment by this method, the temperature at the time of neutralization and reprecipitation needs to be 0 ° C., and the operation is complicated, and a great deal of know-how is required for industrialization. .

In US Pat. No. 3,607,336, two or more quinacridones having different chemical structures are dissolved in sulfuric acid and introduced into high turbulent water. -Turbulance (HT) drowing]
The resulting slurry is heated at a temperature in the range of 40 ° C. to the boiling point for 10 minutes.
A method of performing heat treatment for minutes to 2 hours is described. However, the average particle size of the pigment obtained by this method is relatively large, and the particle size distribution is wide. Besides, not only is the production and drying of each crude quinacridone necessary,
Cost is high because waste acid treatment is required. Furthermore, in order to control the particle size, it is necessary to control the temperature of the water and the mixed turbulence, and it is difficult to produce constant particles.

Japanese Patent Application Laid-Open No. 09-176507 discloses that two or more kinds of quinacridones having different chemical structures and an inorganic salt are preliminarily pulverized by a ball mill or the like, and the obtained semipigment type powder is diluted with sulfuric acid and an organic liquid. A method is described in which, if necessary, a dispersion is dispersed in a medium containing a surfactant, heated to form a pigment, and then the organic liquid is removed to produce the pigment.
However, this method also requires not only the production and drying of crude quinacridone, but also preliminary grinding.
Although the cost of treating waste acid is reduced as compared with the above method, the treatment of inorganic salts also poses a problem.

[0008]

However, the transparency of the quinacridone solid solution pigments obtained by these methods is still insufficient for social needs. The present invention provides a quinacridone solid solution pigment which is more excellent in transparency corresponding to social needs, and
An object of the present invention is to provide a method for producing a quinacridone solid solution pigment which is advantageous for industrially overcoming the drawbacks of the conventional method and is simple to operate with a quinacridone solid solution pigment without complicated steps. .

[0009]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a crude quinacridone solid solution pigment containing unsubstituted quinacridone and 4,11-dichloroquinacridone as essential components, and a quinacridone pigment derivative if necessary. And a heat treatment in a liquid medium containing water and a water-soluble organic solvent, without passing through complicated steps, in a powder X-ray diffraction diagram, a solid solution pigment showing a specific peak intensity at a specific Bragg angle is obtained. It was found that this solid solution pigment was more transparent than those produced by conventional methods, leading to the completion of the present invention.

That is, the present invention provides the following invention. 1. Powder X which contains unsubstituted quinacridone and 4,11-dichloroquinacridone as essential components, and is characterized by CuKα characteristic X-rays (wavelength 1.541 A; Angstrom)
Bragg angle (2θ ± 0.2 °) by X-ray diffraction
In the quinacridone solid solution pigment having peaks at 6.7 °, 13.3 ° and 6.4 °, the respective peak intensities are 5000 to 7500 cps, 2100 to 6500 cps.
A quinacridone solid solution pigment having a ps of 2000 to 5000 cps. 2. The crude quinacridone solid solution pigment containing unsubstituted quinacridone and 4,11-dichloroquinacridone as essential components is heated in a liquid medium in a large excess of the crude quinacridone solid solution pigment to give a quinacridone solid solution pigment. A method for producing a quinacridone solid solution pigment.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the quinacridone solid solution contains unsubstituted quinacridone and 4,11-dichloroquinacridone as essential components, and 4,11-dichloroquinacridone is dissolved in the crystal phase of unsubstituted quinacridone. Are those that form a mixed phase considered to be
Therefore, this solid solution contains unsubstituted quinacridone single crystals,
4,11-Dichloroquinacridone has a peak at the Bragg angle by X-ray powder diffraction that is not present in the single crystal. Therefore, whether the solid solution or the mixture of each single crystal is powder X
It can be easily determined by line diffraction.

The quinacridone solid solution pigment of the present invention has peaks at Bragg angles (2θ ± 0.2 °) of 26.7 °, 13.3 ° and 6.4 °, and each peak intensity is 5000-7500cps, 2100-650
With 0 cps and 2000 to 5000 cps, excellent transparency can be obtained.

In the powder X-ray diffraction pattern of the pigment, the peak intensity is regarded as a substitute characteristic representing the size of the primary particles of the pigment. That is, among pigments having the same crystal structure, a pigment having a lower peak intensity is recognized as having a smaller primary particle diameter. Accordingly, a coating film having higher transparency can be obtained with a pigment having a lower strength. However, when the strength is extremely weak, the pigment particles are extremely agglomerated, and it is often difficult to disperse the pigment particles into primary particles. As a result, a coating film having high transparency cannot be obtained.

Further, the quinacridone solid solution pigment of the present invention comprises:
BET specific surface area by nitrogen adsorption method is 10 to 60 m ² /
It is preferable to have g in terms of obtaining excellent transparency in combination with the peak intensity described above. still,
BET specific surface area in the nitrogen adsorption method in the present invention,
It is measured according to JIS Z 8830-1990 (a method for measuring the specific surface area of powder by gas adsorption).

The particle size of the quinacridone solid solution pigment of the present invention is not particularly limited, but is excellent in hue and dispersibility.
The major axis preferably has an average particle diameter of 0.03 to 0.1 μm.

The quinacridone solid solution pigment of the present invention may further contain a quinacridone pigment derivative in addition to unsubstituted quinacridone and 4,11-dichloroquinacridone. The quinacridone pigment derivative will be described later.

The presence or absence of the quinacridone pigment derivative in the quinacridone solid solution pigment can be confirmed by, for example, an infrared absorption spectrum (IR) or a mass spectrum (MS).

The weight ratio of unsubstituted quinacridone and 4,11-dichloroquinacridone constituting the solid solution pigment is usually 78:22 to 25:75, preferably 60:40 to 40:60. is there. When a quinacridone-based pigment derivative is further used, the amount is preferably 1 to 10% by weight based on the weight of the quinacridone solid solution pigment.

The present invention is characterized in that a crude quinacridone solid solution pigment is used without using a commercially available unsubstituted quinacridone pigment or 4,11-dichloroquinacridone pigment. That is, the process of the present invention eliminates the steps of destructing the separate types of crystals and then rearranging them into solid solution, and the attendant additional processing steps.

The particle size of the crude quinacridone solid solution pigment, which is a raw material of the solid solution pigment, is not particularly limited.
The thickness is 0.05 μm. The crude quinacridone solid solution pigment used here may be in any state, for example, powder, wet cake, slurry, etc., but in the heating step in the next liquid medium, has excellent wettability, and is easy to operate. In view of this, it is preferable to use a wet cake.

The crude quinacridone solid solution pigment used in the present invention can be produced by a conventionally known method. Specifically, for example, there is the following method. (1) 2,5 which is a raw material of crude quinacridone solid solution pigment
-A method in which dianilinoterephthalic acid and 2,5-di-o-chloroaniline are dehydrated and cyclized in polyphosphoric acid, and the resulting precipitate is filtered and washed with water. (2) A crude quinacridone pigment having no substituent and a crude 4,11-dichloroquinacridone pigment are dissolved in polyphosphoric acid or concentrated sulfuric acid, and the resulting solution is poured into water.
How to wash with water.

Here, the weight ratio of 2,5-dianilinoterephthalic acid to 2,5-di-o-chloroaniline for obtaining a crude quinacridone solid solution pigment, or the crude quinacridone pigment and the crude 4,11-dichloroquinacridone The weight ratio with the pigment is usually the former: the latter = 78: 22 to 25: 7.
5, preferably 60:40 to 40:60.

In the present invention, it is advantageous to use the above-mentioned method (1) in that the waste acid treatment and the inorganic salt removal treatment are unnecessary.

In the method (1), a temperature of 100
It is preferable to carry out the dehydration cyclization reaction at ~ 140 ° C for 1-5 hours, and then to crystallize. The crude quinacridone solid solution pigment thus obtained can be purified and dried as necessary. However, after washing with water, hot water, alkali washing, etc., the filtered wet wet cake is dried (not dried). It is preferable to use it in the next step as it is because the step of drying the crude quinacridone solid solution pigment can be omitted. This washing can be performed 1 to 5 times. In particular, the alkali washing is for neutralizing the remaining phosphoric acid, and its use amount needs to be small so that the crude quinacridone solid solution pigment does not dissolve in the liquid medium in the heat treatment described below.

The quinacridone solid solution pigment of the present invention can be preferably produced by heating the above crude quinacridone solid solution pigment in a liquid medium in which a large excess of the crude quinacridone solid solution pigment is not dissolved. .

The liquid medium of the present invention is selected from those which do not dissolve the crude quinacridone solid solution pigment. As this liquid medium, it is preferable to use a liquid medium containing a water-soluble organic solvent as an essential component in order to more stably control the crystal of the crude quinacridone solid solution pigment.

The water-soluble organic solvent used in the present invention includes, for example, dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, ethanol, propanol, butanol, ethylene glycol, and the like. Considering price and safety, use of dimethylformamide or butanol is particularly preferred.

Although the amount of the water-soluble organic solvent is not particularly limited, it may be in the range of 0.1 to 20 times by weight or more based on the weight of the crude quinacridone solid solution pigment, but may be more than that. Only the recovery cost increases. Therefore, the preferred amount of the water-soluble organic solvent is
The equivalent amount of 0.1 to 10 times by weight is most preferable.

Among liquid media containing a water-soluble organic solvent as an essential component, it is particularly preferable to use a liquid medium containing water and a water-soluble organic solvent. In this case, the water content in the liquid medium containing water and the water-soluble organic solvent is 35 to 95% by weight.
So that This prevents dissolution of the crude quinacridone solid solution pigment. In preparing a liquid medium containing water and a water-soluble organic solvent, it is easier to recover the organic solvent from the mixed liquid medium containing water, and even if the heating conditions in the solvent are slightly varied, the intended pigment is not obtained. As a water-soluble organic solvent, dimethylformamide is particularly preferred in that it can be easily obtained.

On the other hand, the amount of the entire liquid medium is not particularly limited, but is preferably in a large excess, especially 5 to 10 times by weight based on the weight of the crude quinacridone solid solution pigment.

The heating temperature of the liquid medium in the production method of the present invention may vary depending on the type of the water-soluble organic solvent used, but may be any temperature of 25 to 140 ° C.
It is preferably carried out at a temperature of from 70 to 100 ° C. Although the heating time is not particularly limited, it is usually 2 to 10 hours in order to obtain a pigment having a more uniform particle size.

This heating can be carried out, for example, by mixing a crude quinacridone solid solution pigment and a liquid medium as essential components and stirring the mixture at the above-mentioned predetermined temperature. In this heating operation, the temperature and the stirring conditions are fixed in advance, and sampling is performed every time, and the powder X-ray diffraction measurement and the BE
The T specific surface area is determined, and in actual production, the quinacridone solid solution pigment is stopped at a time when the powder X-ray diffraction intensity or the BET specific surface area is intended.

By heating the crude quinacridone solid solution pigment in combination with another quinacridone-based pigment derivative in a liquid medium, the sudden crystal growth that may occur may be suppressed and relaxed, and the heating conditions in the solvent may vary somewhat. However, a quinacridone solid solution pigment having intended characteristics can be easily obtained.

The quinacridone pigment derivatives used in the present invention include quinacridonesulfonic acid, pyrazolyl-methylquinacridone and quinacridonesulfonic acid, which are known in the art.
Includes dimethylaminopropylquinacridone monosulfonamide, dimethylaminopropylquinacridone disulfonamide and 2-phthalimidomethylquinacridone. In the case where a wet wet cake is used as the crude quinacridone solid solution pigment, it is preferable to use a wet wet cake as the quinacridone pigment derivative.

The quinacridone pigment derivative can be added to the system during the production process of the crude quinacridone solid solution pigment. In this case, the wet cake of the quinacridone pigment derivative must be dried, Considering the problems such as the chemical stability of the quinacridone-based pigment derivative and the degree of freedom in changing the addition amount, it is preferable to add the crude quinacridone solid solution pigment as a wet cake before heating it in a liquid medium. .

The amount of the quinacridone-based pigment derivative suitable for producing a fine quinacridone solid solution pigment having excellent transparency is suitably 1 to 10% by weight based on the weight of the crude quinacridone solid solution pigment. . Among the above quinacridone-based pigment derivatives, quinacridonesulfonic acid is particularly preferred because it has a large effect of suppressing crystal growth when used in the same amount and can impart excellent applicability to the quinacridone solid solution pigment.

When the above heating is performed, if necessary, an inorganic material such as sodium hydroxide or potassium hydroxide may be used so that the crude quinacridone solid solution pigment and the quinacridone pigment derivative used as needed are not dissolved in the system. A base can be used in combination.

After the heating is stopped, the mixture of the crude quinacridone solid solution pigment and the liquid medium is usually filtered, and the obtained quinacridone solid solution pigment is washed and dried. After the water-soluble organic solvent is removed from the system in advance, these operations can be performed on a mixture of the crude quinacridone solid solution pigment and water.

For the washing, the method for obtaining the above crude quinacridone solid solution pigment can be employed. For drying, a hot air drier or a spray drier can be used.

The quinacridone solid solution pigment of the present invention thus obtained can be used in various known applications such as coloring of printing inks, paints, thermoplastic resin moldings, coloring of photoresists, and toners for developing electrostatic images. Can be used.

[0041]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to test examples with reference to examples and comparative examples, but the present invention is not limited to these examples. In addition, "%" in the following examples is weight% unless otherwise specified.

[Evaluation Method] Powder X-Ray Diffraction The powder of quinacridone solid solution pigment was packed in a predetermined holder, and measured with RINT X-RAY DIFFRACTMETER (model: RINT1100) manufactured by Rigaku Corporation.・ BET specific surface area The specific surface area of the quinacridone solid solution pigment can be measured using an automatic surface area analyzer (AUTOMATIC SURFACE AREA ANALYZER,
(Model: MODEL-4232II, manufactured by MICRO-DATA) using nitrogen gas.

(Evaluation as Colorant) Preparation of Base Coatings 6.0 g of each pigment of Examples and Comparative Examples, 12.0 g of acrylic resin (Acrydic 47-712; manufactured by Dainippon Ink and Chemicals, Inc.), xylene and butanol at a weight ratio of 3: 1. Thinner 16.0 and average diameter 3m
100 ml of 80 g of glass beads are charged. After this mixture was dispersed for 2 hours with a paint shaker, 36 g of an acrylic resin and a melamine resin (Super Beckamine L-1)
17-60; manufactured by Dainippon Ink and Chemicals, Inc.) 10.0
g and mix for 10 minutes to make a paint with 7.5% pigment.

2. Preparation of aluminum paint Aluminum paste (SPARKLE SILVE manufactured by SILVERLINE)
R 5242-AR) 15.75 g, acrylic resin 120 g, melamine resin 25 g and thinner 49.25 g of the above composition
Is mixed well until there are no lumps to obtain an aluminum paint having an aluminum content of 7.5%.

3. Preparation of Colored Product and Hue Evaluation (1) The base paint is colorized on a polyester film using a 6 mil applicator. The film is dried at room temperature for several hours and baked at 140 ° C. for 20 minutes. Colored products (hereinafter referred to as primary color coating films) using the pigments of Examples and Comparative Examples produced in this way were visually evaluated from the back side of the colored surface with a hue using a colorimeter. (2) After 5 g of base paint and 5 g of aluminum are mixed well, the color is spread on a polyester film using a 6 mil applicator. The film is dried at room temperature for several hours and baked at 140 ° C. for 20 minutes. The hue of the thus-prepared colored product (hereinafter, referred to as a metallic coating film) was also performed in the same manner as described above.

Note that, in the colorimetric values described in the following Examples and Comparative Examples, the upper numerical values are the values in the middle when a black paper is laid below the developed material (hereinafter referred to as a black background). Indicates a colorimetric value of a metallic coating film when quinacridone solid solution pigment and aluminum are in a ratio of 1: 1 when white paper is laid below the developed material (hereinafter referred to as white background).
The transparency was judged by L * on a black background and by visual observation.

Production Example of Crude Quinacridone Solid Solution Pigment 458.4 g of 85% phosphoric acid in a 2 L separable flask
Was weighed, and 804.0 g of phosphoric anhydride was added, and 86.6%
Polyphosphoric acid was prepared. When the internal temperature drops to about 100 ° C., OCTA (2,5-bis-o-chloroanilino-
40.0 g of terephthalic acid) and then DATA (2.5
-Dianilino-terephthalic acid) was slowly added. After the addition was completed, a condensation reaction was performed at 120 ° C. for 3 hours.

After completion of the reaction, place 1 in a 12 L stainless steel cup.
The reaction solution was poured into 6 L of water at 2 to 15 ° C. After filtration and washing with water, transfer to a 5 L stainless steel container and add water 3.
2 L was added and stirred, 110 ml of 48% sodium hydroxide was added to adjust the pH to 12 to 14, and the mixture was heated at 80 ° C. for 1.5 hours.

Filter and wash with water and 1190.3 g of a crude quinacridone solid solution pigment wet cake having a solid content of 16.2%.
(Solid content: 175 g) was obtained. Observation of the pigment particles with a transmission electron microscope revealed that the pigment particles were extremely agglomerated due to the extremely fine particle size, and the average particle size could not be determined.

Example 1 In a 1 L cylindrical flask, 510.2 g of a wet cake of the crude quinacridone solid solution pigment obtained in the above Production Example was obtained.
(Solid content: 75.0 g), dimethylformamide 48
After charging and dispersing 7.4 g and 52.8 g of water, p
48% caustic soda (about 4.0 g) was added so that H became alkaline (9.5 ± 1.0), the temperature was raised to 95 ° C. over 1 hour, and the mixture was treated at the same temperature for 5 hours. PH after treatment is about 12
Met. After cooling to 50 ° C or lower, the mixture was filtered, washed with hot water and water until the filtrate became colorless, and dried at 90 ° C.

The quinacridone solid solution pigment was disintegrated with a juicer mixer, and the BET specific surface area was measured.
m ² / g, and the peak intensities at the Bragg angles (2θ ± 0.2 °) of 26.7 °, 13.3 ° and 6.4 ° according to the powder X-ray diffraction pattern (FIG. 1) are as follows: About 5300 cps
Hereinafter, it was about 3700 cps and about 2800 cps.
When the pigment particles were observed with a transmission electron microscope,
The average particle size of the major axis was about 0.05 μm.

L * is the lightness, C * is the saturation, H * is the hue angle, and the colorimetry is SPECTRAFLA, a spectrophotometer manufactured by Data-color.
SH500 type was used. The values obtained when the primary color coating film was measured on a black background are as follows, and it can be seen that this pigment has a smaller value of L * and higher transparency than the pigment of Comparative Example,
The transparency was also high visually.

[0053]

[Table 1]

In addition, from the C * of the white background of the primary color coating film and the C * of the metallic coating film, it was found that the present pigment had higher chroma and clear hue than the pigment of the comparative example. Also had high clarity.

Example 2 In a 1 L cylindrical flask, 476.2 g (solid content: 70.0 g) of a wet cake of the crude quinacridone solid solution pigment obtained in the above Preparation Example, 486.9 dimethylformamide
g, 64.2 g of water, and 21.4 g (solid content: 4.9 g) of a wet cake of quinacridonesulfonic acid,
After dispersing, about 5 g of 48% caustic soda was added so that the pH became alkaline (9.5 ± 1.0), the temperature was raised to 95 ° C. over 1 hour, and the mixture was treated at the same temperature for 5 hours. The pH after the treatment was about 12. After cooling to 50 ° C or lower, the mixture was filtered, washed with hot water and water until the filtrate became colorless, and dried at 90 ° C.

The quinacridone solid solution pigment was disintegrated with a juicer mixer and its specific surface area was measured to be 47 m ² / g.
And the Bragg angle (2) according to the powder X-ray diffraction pattern (FIG. 2).
θ ± 0.2 °) is 26.7 °, 13.3 ° and 6.
The 4 ° peak intensities were about 5500 cps and about 46 cps, respectively.
00 cps and about 3700 cps. When the pigment particles were observed with a transmission electron microscope, the average particle diameter on the long axis was about 0.05 μm.

The values obtained by measuring the color of the primary color coating film against a black background are as follows. It can be seen that the present pigment has a smaller value of L * and higher transparency than the pigment of the comparative example. ,
The transparency was also high visually.

[0058]

[Table 2]

From the C * of the white background of the primary color coating film and the C * of the metallic coating film, it can be seen that the present pigment has a higher chroma and a clearer hue than the pigment of the comparative example. Also had high clarity.

Example 3 In a 1 L cylindrical flask, 476.2 g (solid content: 70.0 g) of the wet cake of the crude quinacridone solid solution pigment obtained in the above Production Example, 47.8 g of isobutanol, and water 2
After charging and dispersing 21.6 g, 2.4 g of 48% caustic soda was added so that the pH became alkaline, the temperature was raised to 88 ° C. over 1 hour, and the mixture was treated at the same temperature for 5 hours. 140 ml of water was added, the temperature was raised to 89 ° C., and isobutanol was distilled off. Filtration, washing with water and drying.

The quinacridone solid solution pigment was disintegrated with a juicer mixer, and the specific surface area was measured to be 41 m ² / g.
And the Bragg angle (2) according to the powder X-ray diffraction pattern (FIG. 3).
θ ± 0.2 °) is 26.7 °, 13.3 ° and 6.
The peak intensity at 4 ° is about 7100 cps and about 61 cps, respectively.
00 cps and about 4500 cps. When the pigment particles were observed with a transmission electron microscope, the average particle diameter of the major axis was about 0.07 μm.

Further, the values obtained by measuring the color of the primary color coating film against a black background are as follows. It can be seen that the present pigment has a smaller value of L * and higher transparency than the pigment of the comparative example. ,
The transparency was also high visually.

[0063]

[Table 3]

COMPARATIVE EXAMPLE 1 A 1 L pressurizable container containing 118.0 g of a crude quinacridone solid solution pigment wet cake (solid content: 20 g) and 812.0 g of dimethylformamide obtained in the same manner as in the production example. After sufficiently stirring, a small amount of caustic soda was added to adjust the pH to about 9. Then, the temperature was raised to 130 ° C. over 1.5 hours,
Heated and stirred for hours. The internal pressure at this time is a maximum of 0.4MP
Met. After allowing the content to cool to room temperature, it was filtered and washed with hot water until the filtrate became colorless.

After the obtained quinacridone solid solution pigment wet cake was dried at 90 ° C., it was disintegrated with a juicer mixer, and the specific surface area was measured to be 36 m ² / g.
According to the powder X-ray diffraction pattern (FIG. 4), the Bragg angle (2θ ± 0.
2) However, the peak intensities at 26.7 °, 13.3 ° and 6.4 ° are 8900 cps, 7223 cps and 59, respectively.
00 cps. When the pigment particles were observed with a transmission electron microscope, the average particle diameter of the long axis was about 0.2 μm.
m.

Further, the values obtained by measuring the color of the primary color coating film against a black background are as follows. This pigment has a very large L * value and low transparency compared to the pigments of the examples. It was clear, and the transparency was quite low visually.

[0067]

[Table 4]

In addition, from the C * of the white background of the primary color coating film and the C * of the metallic coating film, it was found that the present pigment had higher chroma and sharper hue than the pigment of the comparative example. Also had high clarity.

Comparative Example 2 The crude quinacridone solid solution pigment used in Comparative Example 1 was heated at 90 ° C.
To obtain a sandy powdery crude pigment. Next, 20 g of the crude pigment ground in a mortar was dissolved in 300 g of 98% sulfuric acid, and mixed with water using an aspirator to precipitate a quinacridone solid solution pigment. The total volume reached approximately 5 L. The pigment slurry was filtered and washed with hot water until the filtrate became colorless. This filtrate required waste acid treatment.

After the obtained quinacridone solid solution pigment wet cake was dried at 90 ° C., it was disentangled with a juicer mixer, and the specific surface area was measured to be 0.2 m ² / g.
According to the powder X-ray diffraction pattern (FIG. 5), the Bragg angle (2θ ± 0.
2) However, the peak intensities at 26.7 °, 13.3 ° and 6.4 ° are 5200 cps, 2400 cps and 21
It was 40 cps. When the pigment particles were observed with a transmission electron microscope, the average particle size could not be measured because the particles were aggregates.

Further, the values obtained by measuring the color of the primary color coating film against a black background are as follows. The quinacridone solid solution pigment has a very large value of L * and low transparency as compared with the pigment of Example. It was found that the transparency was considerably low visually. evaluated. In the primary color paint film, many spots which are considered to be poorly dispersed pigments were observed.

[0072]

[Table 5]

[0073]

The quinacridone solid solution pigment of the present invention has a specific intensity peak at a specific Bragg angle in powder X-ray diffraction, so that it is excellent in transparency as compared with the conventional quinacridone solid solution pigment. Has a remarkable effect. Further, the production method of the present invention has an effect that a quinacridone solid solution pigment having excellent transparency can be produced with high productivity by a simple operation without going through complicated steps as in the prior art. Therefore, by using the pigment, a good colorant can be obtained in a field requiring transparency such as a metallic paint, a metal ink, a gravure ink, a writing implement, and a color filter.

[Brief description of the drawings]

FIG. 1 is a powder X-ray diffraction diagram of a quinacridone solid solution pigment obtained in Example 1.

FIG. 2 is a powder X-ray diffraction diagram of the quinacridone solid solution pigment obtained in Example 2.

FIG. 3 is a powder X-ray diffraction diagram of the quinacridone solid solution pigment obtained in Example 3.

4 is a powder X-ray diffraction chart of the quinacridone solid solution pigment obtained in Comparative Example 1. FIG.

5 is a powder X-ray diffraction diagram of the quinacridone solid solution pigment obtained in Comparative Example 2. FIG.

Claims (9)

[Claims] An unsubstituted quinacridone and 4,11-dichloroquinacridone as essential components, and a Bragg angle (2θ ± 0.2) based on a powder X-ray diffraction pattern by CuKα characteristic X-ray (wavelength: 1.541 A; Angstrom).゜)
However, in a quinacridone solid solution pigment having peaks at 26.7 °, 13.3 ° and 6.4 °, the respective peak intensities are 5000 to 7500 cps, 2100 to 650 cps.
A quinacridone solid solution pigment having 0 cps and 2000 to 5000 cps. 2. A BET specific surface area by a nitrogen adsorption method of 1
Quinacridone solid solution pigment of claim 1 wherein the 0~60m ² / g. 3. The long axis has an average particle size of 0.03 to 0.1.
3. The pigment according to claim 1, which has a size of μm. 4. The pigment according to claim 1, further comprising a quinacridone pigment derivative. 5. A crude quinacridone solid solution pigment containing unsubstituted quinacridone and 4,11-dichloroquinacridone as essential components is heated in a liquid medium in excess of the crude quinacridone solid solution pigment to form a quinacridone solid solution pigment. A method for producing a quinacridone solid solution pigment according to claim 1. 6. The method according to claim 4, wherein the liquid medium is a liquid medium containing a water-soluble organic solvent as an essential component. 7. The method according to claim 5, wherein the liquid medium is a liquid medium containing water and a water-soluble organic solvent. 8. The production method according to claim 6, wherein the heating is performed to a temperature of 70 to 100 ° C. 9. The method of claim 5, wherein the crude quinacridone solid solution pigment is heated in the presence of a quinacridone-based pigment derivative.
9. The production method according to 7 or 8.