JPS6035055A - Production of quinacridone solid solution pigment - Google Patents

Abstract

PURPOSE:To obtain a pigment in a simple, shortened treating process with less cost, by dissolving crude unsubstituted quinacridone and a quinacridone compd. in an aprotic polor org. solvent and reprecipitating them. CONSTITUTION:A mixture of crude unsubstituted quinacridone and a quinacridone compd. is dissolved in an aprotic polor org. solvent in the presence of caustic alkali to form a homogeneous soln. The soln. is neutralized with an acid to reprecipitate them, thus obtaining the desired pigment. Examples of the quinacridone compds. are 2,9-dimethylquinacridone, 4,11-dichloroquinacridone and 6,13- dihydroderivatives thereof. Examples of the aprotic solvents are dimethyl sulfide, N-methylpyrrolidone, etc. Preferred caustic alkalis include sodium hydroxide and potassium hydroxide. Examples of the acids are sulfuric acid, hydrochloric acid, acetic acid, etc., and sulfuric acid is particularly preferred.

Description

[Detailed description of the invention] Concerning a simple method for producing pigments.

Regarding solid solution formation of pigments by combining various quinacridone derivatives, US Pat. No. 3,160,510 and 52
98847, and is already a known fact. This solid solution technology provides a powerful means for expanding the color gamut of quinacridone pigments and improving weather resistance and other properties, and is a technology that is expected to continue to develop further. For its production, a large amount of sulfuric acid is required, the size of the pigment particles cannot be controlled arbitrarily, and when solid type pigments with large particle sizes are used, solid solution formation is difficult to proceed sufficiently. It has the following drawbacks, and overall it lacks ease of operation.

In order to improve these shortcomings, the present inventors conducted extensive research on a method for producing solid solution pigments that is easy to operate and allows for arbitrary control of particle size.
It was confirmed that many quinacridone derivatives dissolve in polar organic solvents such as dimethyl sulfoxide in the presence of caustic alkali, and the inventors discovered that the quinacridone derivatives can be applied to the formation of pigments, leading to the present invention. That is, in the present invention, solutions of various quinacridone derivatives in a polar organic solvent such as dimethyl sulfoxide are mixed in an arbitrary ratio to form a homogeneous mixed solution, and then each crystal is prepared by neutralizing and reprecipitating with an acid. Particles can be controlled arbitrarily in the range of 005 to [L25 microns by producing a crystal system with a different form that is clearly different from the system mixture system and adjusting the temperature during neutralization and reprecipitation. Another object of the present invention is to provide a method for producing solid solution pigments that is simple, has short processing steps, does not involve treatment with a large amount of waste acid, and is advantageous in terms of equipment and cost.

That is, the present invention involves dissolving and mixing various quinacridone derivatives in arbitrary ratios of two or more in a polar organic solvent such as dimethyl sulfoxide in the presence of caustic alkali, and then neutralizing and re-mixing with an acid such as sulfuric acid. It is characterized by forming a solid solution by precipitation, and this requires that the various quinacridone derivatives form a salt with a caustic alkali and be completely dissolved in a polar organic solvent such as dimethyl sulfoxide. Examples of such types of quinacridones, other than unsubstituted quinacridone, include 2.4-dimethylquinacridone, 4.
Examples include 11-dichloroquinacridone and 413-dihydroquinacridone, but substituents that do not have to be affected by hydrolysis with alkali, such as alkyl groups other than methyl.

Derivatives containing halogens other than chlorine can be used in the same manner. Regarding the combination of two or more of these, there is no particularly defined composition range for forming a solid solution, and it can be done in any ratio, and by appropriately adjusting the neutralization and reprecipitation conditions, pigment The particle size can also be arbitrarily manufactured within the range of 105 to 025 microns. In manufacturing such solid solution pigments, it is assumed that the combination of crude pigments as raw materials will form caustic alkali and salt in the solvent and dissolve completely. Examples include dimethyl sulfoxide and dimethylimidazolidinone.

Examples include N-methylpyrrolidone, but dimethylsulfoxide is better in terms of solubility and solvent recovery.

These solvents are difficult to dissolve completely in a completely non-aqueous state, but
Mixing a small amount of water increases solubility and facilitates complete dissolution. However, when the water content exceeds 20%, the solubility decreases again and complete dissolution is no longer achieved. Usually, a water content of about 10 to 15 inches is most effective. This is because caustic alkali has poor solubility in these solvents in a completely non-aqueous state, hindering salt formation with quinacridone or quinacridone derivatives. As the caustic alkali used in this dissolution operation, caustic soda and caustic potash are preferably used. This is because alkalis other than these have poor solubility.

The obtained mixed solution consisting of a combination of various quinacridone derivatives is converted into a solid solution pigment by setting neutralization and reprecipitation conditions according to the intended use of the pigment. At this time, as acids used for neutralization, sulfuric acid, hydrochloric acid, acetic acid, etc. can be used, but sulfuric acid is the best when considering the weather resistance of the resulting material.

As for neutralization and reprecipitation conditions, the temperature during neutralization and reprecipitation has a large effect on particle size, so it is necessary to perform neutralization and reprecipitation while controlling the temperature to be suitable for obtaining the desired particle size. Usually 0.2 to 0.25 microns at 60℃, 4
[115~α2 micron at 0℃ range, α1~α at 20℃ level]
Since the particle size varies from 15 microns to α05 to 11 microns at 0° C., the desired particle size may be selected within this range.

The precipitate slurry obtained by neutralization and reprecipitation is filtered and washed using normal means, and if necessary, surface treatment is applied to produce a product with excellent coloring power, clarity, and heat resistance.

Obtain a finely divided solid solution pigment with great light resistance.

Formation of a solid solution can be easily confirmed by X-ray diffraction analysis of the resulting product pigment.

In the case of a simple mixture, the X-ray diffraction pattern corresponds to a superposition of the unique X-ray diffraction patterns of each mixture, and the peak intensity is proportional to the blending ratio, but it does not indicate the formation of a solid solution. In some cases, the difference between the two can be clearly distinguished by showing a diffraction pattern with unique characteristics of the newly formed crystal.

In order to clarify these facts, explanation will be given based on drawings. In FIG. 1, (11 is γ-type quinacridone, (2) is λ9-dimethylquinacridone, (3) is a mixture of r-type quinacridone and 2.9-dimethylquinacridone at a ratio of 6:4 (weight ratio), (4 ) respectively show characteristic patterns of the X-ray diffraction diagram of a solid solution of unsubstituted quinacridone and 2,9-dimethylquinacridone, which is an embodiment of the present invention.

In addition, in Fig. 2, (1) is γ-type quinacridone, (2) is 4,11-dichloroquinacridone, and (3) is 6=4 of r-type quinacridone and 4,11-dichloroquinacridone.
(weight ratio), (4) shows the characteristic patterns of the X-ray diffraction diagram of a solid solution of unsubstituted quinacridone and 4,11-dichloroquinacridone, which is another embodiment of the present invention. . The X-ray diffraction angle 2θ in each drawing was measured using a 0uKdN i filter.

From these facts, it is clear that all the solid solutions of the present invention exhibit novel patterns.

The solid solution pigment formation method according to the present invention has the following features compared to known methods, and is extremely advantageous from an industrial perspective.

These are as follows: (1) Since it dissolves uniformly in a polar organic solvent such as dimethyl sulfoxide, it is easy to remove foreign substances.

■ The crystal form of the crude pigment used as a raw material does not matter.

■ The melting operation can be completed in a short time without requiring high temperatures.

■ By controlling the temperature during neutralization and reprecipitation, particle tolerance can be controlled as desired.

■ Since there is no contamination of the solvent system with anything other than quince, it is easy to recover and reuse the solvent.

■ The entire process is extremely simple and short, so productivity is good regardless of the scale.

(There is no particularly defined compositional range in which it is necessary to form a solid solution, and any combination and ratio can be used.

etc.

Hereinafter, the present invention will be explained in more detail with reference to examples.

Example 1 15 parts of crude unsubstituted quinacridone 1, 4.5 parts of crude 2,9-dimethylquinacridone, and 150 parts of dimethyl sulfoxide containing 10% of water were weighed into a flask,
Add 77.5 parts of caustic force I with stirring to form a homogeneous slurry.

When stirring is continued at room temperature, the system gradually turns blue-purple, changing from a slurry to a deep blue-purple solution.

After stirring for about 1.5 hours, if necessary, use a filter to remove trace amounts of insoluble matter, cool and keep warm at 0°C, and add sulfuric acid water diluted with 5 parts of sulfuric acid to 1010 parts. Slowly pour the mixture through the dropping funnel over a period of about 5 minutes. As the neutralization progresses, the system becomes a slurry again and rapidly thickens, so the stirring speed is increased as the viscosity increases. When the slurry is finished, stirring is continued to maintain a sufficiently homogeneous slurry, and the slurry is aged for 1 hour. The slurry is diluted with 150 parts of water to lower the viscosity of the slurry, and then filtered using a filter. The obtained cake-like material was re-dispersed and washed with water in Step 11 using a dispersing mixer, and then F
treat This operation was repeated three times before and after drying for 12 hours in a hot air dryer at 60° C. to obtain the desired solid solution pigment with a recovery rate close to a quantitative amount.

Confirmation that this substance has formed a solid solution is performed by X-ray diffraction. That is, in the γ-type crystal phase, a mixture of unsubstituted quinacridone and 2,9-dimethylquinacridone is
-In contrast to the superposition of the line diffraction patterns, the product of this example is 5,95° in 2θ.

156°, 26. A high intensity peak was observed at 5°EL and 27.4°, and a weaker intensity peak was observed at 12.0°, clearly indicating that a different type of crystal form was formed, indicating solid solution formation (see Figure 1). ).

As a result of observing the particle state using an electron microscope photograph (20,000x magnification), it was confirmed that the particles were fine particles with an average distribution of around n and os microns, and the coloring exhibited excellent transparency in the coating test. The results of the accelerated weathering test also confirmed that the solid solution product shows less deterioration and has better light resistance than a mixed toned product of the same composition.

Example 2 Example 10 2.9-dimethylquinacridone to 4.11-
The treatment was carried out under the same conditions except that dichloroquinacridone was used, and a red pigment powder with a very strong yellowish tinge was almost quantitatively obtained. Formation of a solid solution was confirmed using an X-ray diffraction chart in the same manner as in Example 1. ．． 1°, 151
Strong peaks at 12.7° and 24°, 2 & 5°
It was confirmed that a simple toning mixture showed a diffractogram of a superposition of unique patterns, but a different type of crystal form clearly indicating solid solution formation was produced ( (See Figure 2).

According to the observation results using an electron microscope fs (transmission type 20,000 times), α0
It was found to have an extremely narrow particle size distribution on the order of 5 microns, and the accelerated weathering test results were also extremely good compared to the toned mixture.

[Brief explanation of the drawing]

FIGS. 1 and 2 show an X-ray diffraction diagram of a conventionally known quinacridone and an X-ray diffraction diagram of a solid solution obtained in one embodiment of the present invention. In all measurements, the X-ray diffraction angle 2θ was measured using an OuKαN1 filter. Patent applicant: Toyo Ichida Kogyo Co., Ltd. No. 1 Figure 5° 10" 15° 20" 25° 30@da 1
0° 15' 2σ 25"30'Figure 2

Claims (1)

[Scope of Claims] [1] Solid solution formation characterized by dissolving a mixture of crude unsubstituted quinacridone and a quinacridone compound in an aprotic polar organic solvent in the presence of caustic alkali, and neutralizing and reprecipitating with an acid. A method for producing quinacridone pigments. 2) The production method according to claim (1), wherein λ9-dimethylquinacridone, 4,11-dichloroquinacridone, or a 415-dihydroquinacridone derivative thereof is used as the quinacridone compound. (3) The manufacturing method according to claim 11+ or (2), wherein the caustic alkali is caustic soda or caustic potash. (4) As described in any one of claims (1) to (3), in which dimethyl sulfoxide, dimethylimidazolidinone, or I/i, N-methylpyrrolidone is used as the aprotic polar organic solvent. manufacturing method. (ω) The manufacturing method according to any one of claims 11 to 11, in which sulfuric acid, hydrochloric acid, or acetic acid is used as the acid.