TWI772405B - Method for producing quinacridone solid solution pigment, pigment dispersion and ink for inkjet - Google Patents

Abstract

The present invention provides a quinacridone solid solution pigment technology that can form a quinacridone solid solution pigment with high chroma and a moderately yellowish phase, and can obtain the desired hue of the quinacridone solid solution pigment by controlling the particle size. The method for producing the quinacridone solid solution pigment provided by the present invention is to perform a co-cyclization reaction between diarylamine terephthalic acid and dialkylarylamine terephthalic acid in polyphosphoric acid to obtain unsubstituted terephthalic acid. In a solid solution with a mass ratio of quinacridone to 2,9-dialkylquinacridone of 85:15 to 60:40, the crude quinacridone solid solution in a water-containing state containing water, will be dried as described above using the drying step. Obtain the crude quinacridone solid solution in a water-containing state and dry it to obtain a powdery crude quinacridone solid solution with a moisture content of less than 1%, and then in the pigmentation step, the above-mentioned powdery crude quinacridone solid solution is , heating is performed in a liquid medium that does not dissolve the crude quinacridone solid solution. The present invention also provides a pigment dispersion liquid and an inkjet ink containing the obtained quinacridone solid solution pigment.

Description

Method for producing quinacridone solid solution pigment, pigment dispersion and ink for inkjet

The present invention relates to a method for producing a quinacridone solid solution pigment, a pigment dispersion and an ink for inkjet. In detail, it provides: when applied as a colorant, the obtained colorant has high chroma and can become a quinacridone solid solution pigment having a desired moderate yellowish phase, and can be controlled to be suitable for spraying. A method for producing a quinacridone solid solution pigment of a quinacridone solid solution pigment with a particle size of an ink for ink, a pigment dispersion liquid containing a quinacridone solid solution pigment of a characteristic hue obtained according to the production method, and an ink for inkjet technology.

It is known that quinacridones are synthetic pigments with bright color and weather resistance, and are typically red to purple. The hue is affected by the substituents on the conjugated ring and the crystal structure. For the quinacridone solid solution pigment, which is one of the fields of quinacridone pigments, there have been many studies in the field of organic pigments. For example: quinacridone pigment composed of solid solution of unsubstituted quinacridone and 2,9-dimethylquinacridone; quinacridone composed of solid solution of unsubstituted quinacridone and quinacridone quinone Pigment C.I. Pigment Red 206, and C.I. Pigment Red 207, a quinacridone pigment composed of a solid solution of unsubstituted quinacridone and 4,11-dichloroquinacridone, etc. (refer to Patent Documents 1 and 2).

[Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2000-281930

[Patent Document 2] Japanese Patent Laid-Open No. 2002-146224

However, there is still a problem that the chroma of the colorant obtained from the quinacridone solid solution pigment is insufficient. In addition, in recent years, the market has demanded a quinacridone solid solution with a yellowish phase, but there has not been a quinacridone solid solution with a high chroma and a moderately yellowish phase that can fully meet the market demand. In addition, for example, pigments used in colorants for inkjet inks are required to be fine and uniform in particle size, but solid solution pigments have a problem that it is difficult to control the size of the fine particle size and become uniform.

The purpose of the present invention is to provide: when used as a colorant, it can form a quinacridone solid solution pigment with high chroma and a desired moderately yellowish coloring matter, and it is more preferable to control the particle size to obtain the desired quinacridone solid solution pigment. Quinacridone solid solution pigment technology for particle size quinacridone solid solution pigments. Also, the object of the present invention is: for example, by developing a technology that is quite suitable for ink-jet ink colorants such as the above-mentioned excellent quinacridone solid solution pigments, it is possible to provide a colorant that can form high chroma and has a yellowish phase coloring. Pigment dispersions and inkjet inks.

The above-mentioned problems of the conventional technology can be achieved by the following invention. That is, the present invention provides:

[1] A manufacturing method of a quinacridone solid solution pigment, comprising: a manufacturing step of a crude quinacridone solid solution, a drying step of drying the crude quinacridone solid solution, and a drying step of the crude quinacridone solid solution The pigmentation step of heating the solid solution in a solvent and pigmentation; wherein, the production step of the above-mentioned crude quinacridone solid solution is in polyphosphoric acid, and diarylamino terephthalic acid and dialkylarylamino terephthalic acid are made. The acid undergoes a co-cyclization reaction to obtain a solid solution of unsubstituted quinacridone and 2,9-dialkyl quinacridone, in a solid solution with a mass ratio of 85:15~60:40, containing water. The crude quinacridone solid solution in a water-containing state; the above-mentioned drying step is to dry the crude quinacridone solid solution in the above-mentioned water-containing state, so that the moisture content is less than 1%, and a powdery crude quinacridone solid solution is obtained; The above-mentioned In the pigmentation step, the above-mentioned powdery crude quinacridone solid solution is heated in a liquid medium that does not dissolve the crude quinacridone solid solution.

The preferred form of the manufacturing method of the above-mentioned quinacridone solid solution pigment of the present invention can be, for example, as follows:

[2] The method for producing a quinacridone solid solution pigment according to [1], wherein the diarylamino terephthalic acid is 2,5-diphenylamino terephthalic acid; Phthalic acid is 2,5-bis(p-toluidine) terephthalic acid.

[3] The method for producing a quinacridone solid solution pigment according to [1] or [2], wherein, in the pigmentation step, the powdery crude quinacridone solid solution is applied in the liquid medium. During heating, the quinacridone-based pigment derivative is allowed to exist.

[4] The method for producing a quinacridone solid solution pigment according to [3], wherein the quinacridone-based pigment derivative is 2-phthalimidomethylquinacridone.

[5] The method for producing a quinacridone solid solution pigment according to any one of [1] to [4], wherein the liquid medium in which the crude quinacridone solid solution does not dissolve is dimethylsulfoxide.

[6] The method for producing a quinacridone solid solution pigment according to [5], wherein the heating temperature in the pigmentation step is 60°C or higher and 120°C or lower.

[7] The method for producing a quinacridone solid solution pigment according to any one of [1] to [6], which is for obtaining a quinacridone solid solution pigment with a long-axis particle diameter of 20 to 80 nm .

Another embodiment of the present invention provides the following pigment dispersion.

[8] A pigment dispersion liquid comprising: a quinacridone solid solution pigment of unsubstituted quinacridone and 2,9-dialkylquinacridone, a pigment dispersant, and water; wherein the quinacridone solid solution The solution pigment has specific diffraction peaks of 27.5°, 13.8° and 6.0° using the Bragg angle (θ) of (2θ±0.2°) 2θ values in powder X-ray diffraction.

Another embodiment of the present invention provides the following inkjet inks.

[9] An ink for inkjet, comprising: a quinacridone solid solution pigment, a pigment dispersant and an inkjet ink composed of water, the quinacridone solid solution pigment is composed of unsubstituted quinacridone and 2, The solid solution composition of 9-dialkylquinacridone, and the long-axis particle diameter is 20~80nm; wherein, the above-mentioned quinacridone solid solution pigment is in powder X-ray diffraction, and has the use of Bragg angle (θ). The 2θ values of (2θ±0.2°) are specific diffraction peaks at 27.5°, 13.8° and 6.0°.

According to the present invention, a quinacridone solid solution pigment without substituted quinacridone and 2,9-dialkyl quinacridone can be provided with high chroma and required moderate yellowish phase. Furthermore, in addition to the above-mentioned effects, according to the preferred embodiment of the present invention, there is still a quinacridone solid solution pigment whose particle size is controlled to an appropriate size, which is an important requirement for practical application. Furthermore, according to the present invention, by using the above-mentioned excellent quinacridone solid solution pigment, it is possible to provide a pigment dispersion liquid and an inkjet ink which can obtain high chroma and have a desired moderately yellowish coloring matter.

Next, the present invention will be described in more detail by citing preferred embodiments for carrying out the present invention. The inventors of the present invention have completed the present invention through intensive research in order to solve the above-mentioned problems of the conventional technology. First, it is known that when a solid solution pigment of unsubstituted quinacridone and 2,9-dialkylquinacridone is formed, in order to make the hue of the obtained pigment yellowish, the mass ratio must be set to 85:15~60 : 40. Therefore, a crude quinacridone solid solution in an aqueous state containing water in the solid solution of the unsubstituted quinacridone and 2,9-dialkylquinacridone in the above mass ratio was obtained, and by pigmenting the solid solution, the Can produce yellowish quinacridone solid solution pigment.

The inventors of the present invention have conducted further studies in order to achieve the above-mentioned object of the present invention. First, in the solid solution of the unsubstituted quinacridone and 2,9-dialkyl quinacridone in the mass ratio above, the crude quinacridone solid solution in the aqueous state containing water is obtained by adding in polyphosphoric acid, It can be obtained by the co-cyclization reaction of diarylamine terephthalic acid and dialkylarylamine terephthalic acid. The manufacturing method of the quinacridone solid solution pigment of the conventional unsubstituted quinacridone and 2,9-dialkyl quinacridone is to make the crude quinacridone solid solution in the water-containing state produced in this way, in the water-containing state. , heated in a solvent for pigmentation. According to the review by the inventors of the present invention, it is found that the pigment obtained by pigmentation according to such a conventional production method is more yellowish than the crude quinacridone solid solution of the raw material, which is not the purpose of the present invention. The chroma is high, and the desired moderate yellowish hue is present. The inventors of the present invention have conducted further investigations in order to find a method for producing a quinacridone solid solution pigment which can improve this point and make the color material exhibit the high chroma required by the market, and a moderately yellowish good hue.

As a result, the inventors of the present invention newly provided a drying step for forming a powdery crude quinacridone solid solution before the pigmentation step with respect to the above-mentioned conventional method for producing a quinacridone solid solution pigment, and performed the drying step by using the drying step. Dry to a moisture content of less than 1%, and then perform pigmentation by applying the dried powdery crude quinacridone solid solution, thereby utilizing the coloring matter formed by the quinacridone solid solution pigment thus obtained, compared to The coloring matter formed using the solid solution pigment obtained by the conventional manufacturing method can have high chroma and a moderately yellowish good hue. Furthermore, according to the examination of the present inventors, it was found that the particle diameter of the obtained quinacridone solid solution pigment can be controlled to a desired fine size by appropriately setting the production method of the present invention. In particular, according to the preferred embodiment of the present invention, it is also possible to provide a quinacridone solid solution pigment having a particle size suitable for ink jet inks that require ink discharge stability.

<Production method of quinacridone solid solution pigment>

The method for producing a quinacridone solid solution pigment of the present invention comprises the following steps: a step of obtaining a crude quinacridone solid solution in a water-containing state of a specific composition; a drying step of drying the crude quinacridone solid solution in a water-containing state; And the pigmentation step of heating the dry powdery crude quinacridone solid solution in a solvent to make it pigmented; wherein, the new setting is: drying the crude quinacridone solid solution in a water-containing state of a specific composition to make the moisture content less than 1% drying step. Specifically, first, in the same manner as the conventional method for producing crude quinacridone solid solution, the mass ratio of unsubstituted quinacridone and 2,9-dialkylquinacridone of 85:15 to 60:40 was obtained, and Crude quinacridone solid solution in aqueous state with a yellowish hue. Then, using the drying step featured in the present invention, the crude quinacridone solid solution in a water-containing state with the specific composition obtained above is dried until the moisture content is less than 1% to obtain a powdery crude quinacridone solid solution. Then, the powdery crude quinacridone solid solution having a moisture content of less than 1% was pigmented by the pigmentation step performed. In the pigmentation step, in the same manner as in the conventional production method, heating is performed in a liquid medium in which the crude quinacridone solid solution does not dissolve to be pigmented. According to the review by the inventors of the present invention, according to the above-mentioned production method of the present invention, if the crude quinacridone solid solution in a water-containing state of a specific composition is dried to a water content of less than 1%, the hue is slightly shifted compared with that in the water-containing state. Blue to yellowish. As a result, it was found that the quinacridone solid solution pigment finally obtained by pigmentation can be a good hue with high chroma and moderate yellowishness.

Furthermore, according to the review of the present inventors, in the above-mentioned pigmentation step, by using dimethyl sulfoxide as a liquid medium, the particle size of the obtained quinacridone solid solution pigment can be stably controlled to an appropriate size. In particular, when the pigment is heated in such a liquid medium, the particle size of the obtained quinacridone solid solution pigment can be stably changed by setting the heating temperature in the range of 60°C or higher and 120°C or lower. Control the size suitable for use.

Furthermore, according to the review by the present inventors, when the dried powdery crude quinacridone solid solution is heated in a liquid medium to be pigmented, the presence of a quinacridone-based pigment derivative can further increase the level of quinacridone. Acridine solid solution pigment particles exhibit a uniform effect and an effect of improving the chroma of the coloring matter.

The so-called "quinacridone solid solution pigment" here refers to a pigment that exists in a uniform solid state in a mixed state in which a plurality of different quinacridone pigment molecules are co-dissolved, not simply a mixture of a plurality of different quinacridone pigments. . It is known that the formation of a solid solution causes changes in properties such as color. In the present invention, the objective is to produce "a solid solution of unsubstituted quinacridone and 2,9-dialkylquinacridone". In addition, individually, the unsubstituted quinacridone series corresponds to C.I. Pigment Violet 19, and the 2,9-dialkylquinacridone series corresponds to C.I. Pigment Red 122. Hereinafter, each step of the production method of the present invention will be described.

(Production step of crude quinacridone solid solution)

In the production method of the present invention, firstly, using the production step of the crude quinacridone solid solution, a specific ratio of unsubstituted quinacridone and 2,9-dialkyl quinacridone is obtained, and the crude quinacridone in a water-containing state is hydrated solid solution. Specifically, in polyphosphoric acid, the co-cyclization reaction of diarylamino terephthalic acid and dialkylarylamino terephthalic acid is carried out, and the water-containing crude quinacridone solid solution of the above-mentioned constitution is easily obtained. This step is the same as the conventional method for obtaining a quinacridone-based solid solution pigment. In addition, in the conventional production method, the pigmentation of the crude quinacridone solid solution is directly performed while maintaining the water-containing state.

Preferably, the diarylamino terephthalic acid used in the above-mentioned steps is, for example, 2,5-diphenylamino terephthalic acid. Moreover, as a dialkylarylamino terephthalic acid, for example, 2, 5- bis(p-toluidine) terephthalic acid is preferable. In order to more stably obtain the quinacridone solid solution pigment which can make the coloring matter have high chroma and have a moderate yellowish phase, which is the ultimate objective of the present invention, it is preferable to use these compounds.

According to the review by the inventors of the present invention, in order to obtain the quinacridone solid solution pigment required by the market, the coloring matter is high chroma and has a moderate yellowish hue. The mass ratio of unsubstituted quinacridone and 2,9-dialkylquinacridone in the ketone solid solution must be set to 85:15~60:40.

(drying step)

The production method of the present invention is different from the conventional production method of quinacridone solid solution pigment, and is characterized in that: it is necessary to use a newly provided drying step to obtain the above-mentioned crude quinacridone solid solution according to the production step of the crude quinacridone solid solution. The formed crude quinacridone solid solution in a water state is dried to obtain a powdery crude quinacridone solid solution with a moisture content of less than 1%, and the dried crude quinacridone solid solution is then pigmented. As mentioned above, the present invention firstly obtains a yellowish yellow crude quinacridone solid solution of the raw material, and the mass ratio of unsubstituted quinacridone to 2,9-dialkylquinacridone is 85:15-60:40. Then, the crude quinacridone solid solution in the water-containing state is used to form a moisture content of less than 1% by the drying step specified in the present invention, and then the pigmentation is carried out to obtain a coloring agent that can be used as a colorant. It is a useful quinacridone solid solution pigment with high chroma and moderate yellowish hue. The key point of the present invention is: obtaining the water-containing state crude quinacridone solid solution of the above-mentioned unique composition, and fully drying it to form a powdery crude quinacridone solid solution with a moisture content of less than 1%, and then the powdery crude quinacridone solid solution is formed. Acridine solid solution is pigmented.

The technical feature of the present invention is that the mass ratio of the unsubstituted quinacridone and 2,9-dialkylquinacridone constituting the crude quinacridone solid solution is made into a specific composition, and furthermore, the conventional manufacturing method is updated and set up. The drying step of the hydrated crude quinacridone solid solution was performed, and the moisture content of the hydrated crude quinacridone solid solution was set to less than 1%. As a result of the above constitution, a quinacridone solid solution pigment that can be used as a colorant with high chroma and a moderately yellowish hue can be obtained stably.

On the other hand, as described above, when the crude quinacridone solid solution in the water-yellow state is directly pigmented, the yellowishness is enhanced, and the pigment of the desired hue cannot be obtained. Furthermore, according to the review of the inventors of the present invention, when the drying is performed but not sufficiently dried (specifically, the moisture content reaches 1% or more), the coloring matter formed will not be the object of the present invention, and the coloring matter has high chroma and moderate partiality. Pigment with a good yellow hue. Specifically, the b ^* of the formed coloring matter becomes too large, resulting in the coloring matter hue formed by the finally obtained quinacridone solid solution pigment, which is more yellowish than the target hue, and is not a moderately yellowish hue required by the market in recent years. 's coloring. This point will be described later.

(pigmentation step)

In the production method of the present invention, the "powdered crude quinacridone solid solution with a moisture content of less than 1%" obtained in the pigmentation step is heated in a liquid medium in which the crude quinacridone solid solution does not dissolve to be pigmented . This step is basically the same as the pigmentation method employed in the conventional method.

The liquid medium that does not dissolve the crude quinacridone solid solution used in pigmentation can be, for example, dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, ethanol, propanol, butanol, and ethylene glycol. In Patent Document 2 listed in the aforementioned conventional technique, among the above, dimethylformamide and butanol are preferable. In addition, Patent Document 2 discloses that the heating temperature may be any temperature of 25 to 140°C.

In order to achieve the object of the present invention and obtain more obvious effects, the inventors of the present invention have conducted intensive studies on the pigmentation step constituting the production method of the present invention. As a result, it was found that it is more effective to first focus on the type of liquid medium used, and more specifically on the temperature at which the liquid medium is heated. That is, when dimethyl sulfite is used as the liquid medium in which the crude quinacridone solid solution does not dissolve, it was found that when the heating temperature in the pigmentation step is 60°C or higher and 120°C or lower, a better Quinacridone solid solution pigment.

Specifically, as described above, the present inventors found that the crude quinacridone solid solution obtained in a water-containing state was dried to a moisture content of less than 1% by a newly provided drying step, and then the powdery crude quinacridone was dried. Pigmentation of the ketone solid solution is effective. In addition, if the pigmentation step is used, the powder of the crude quinacridone solid solution is heated in a dimethyl sulfoxide solvent, and the obtained quinacridone solid solution can be obtained. The particle size of the pigment is controlled to an appropriate desired size. In addition, by setting the heating temperature at this time within a specific temperature range of 60°C or higher and 120°C or lower, the particle size of the obtained quinacridone solid solution pigment can be controlled more stably to whatever is suitable for the application. size required.

For example, when a colorant is dispersed in an aqueous medium to constitute an inkjet ink, and when a fine quinacridone solid solution pigment used in the colorant is obtained, if the heating temperature exceeds 120°C, the particle size of the quinacridone solid solution pigment will change. for too large. On the other hand, when the heating temperature is lower than 60°C, the particle size of the quinacridone solid solution pigment becomes too small, and in any case, it is difficult to obtain a quinacridone solid solution pigment that is good in an aqueous medium. dispersion.

According to the review by the present inventors, the effect of controlling the particle size of the quinacridone solid solution pigment obtained above is particularly significant when dimethylsulfoxide is used as the solvent used in the pigmentation step.

Furthermore, according to the review by the inventors of the present invention, when the dried powdery crude quinacridone solid solution is heated in dimethyl sulfoxide using the pigmentation step, a quinacridone-based pigment derivative is further added. It is an effective practice to carry out pigmentation in the presence of quinacridone-based pigment derivatives. With this configuration, the particle uniformity effect of the obtained quinacridone solid solution pigment and the effect of improving the chromaticity of the formed coloring matter can be further enhanced. The quinacridone-based pigment derivative used above may be, for example, 2-phthalimidomethylquinacridone.

<Quinacridone Solid Solution Pigment>

According to the quinacridone solid solution pigment obtained by the production method of the present invention, as mentioned above, the unsubstituted quinacridone and 2,9-dialkylquinacridone are essential components, and these are formed into a specific mass ratio, forming In the crystalline phase of the unsubstituted quinacridone, a mixed phase of 2,9-dialkylquinacridone was dissolved. Therefore, it has a specific winding angle that is not present in the unsubstituted quinacridone single crystal and the 2,9-dialkylquinacridone single crystal, and the Bragg angle (θ) measured by powder X-ray diffraction is represented by (2θ). Spectral peaks. Therefore, whether the pigment is a solid solution or a mixture of these single crystals can be easily determined by powder X-ray diffraction.

The quinacridone solid solution pigment obtained according to the production method of the present invention can provide a quinacridone solid solution pigment with high chroma and a moderately yellowish good hue, and the Bragg angle (θ) of (2θ±0.2°) is used in powder X-ray diffraction. The 2θ values are 27.5°, 13.8° and 6.0°, which are characterized by specific diffraction peaks. More specifically, it is characterized in that unique diffraction peaks appear at 2θ values of 27.3° to 27.7°, 13.6° to 14.0°, and 5.8° to 6.2°. Furthermore, when the 6.0° peak intensity defined in the present invention is set to 100, the 13.8° peak intensity ratio is 70 to 80, and the 27.5° peak intensity ratio is 55 to 70.

The particle size of the quinacridone solid solution pigment obtained by the production method of the present invention is not particularly limited, and it may be appropriately produced according to the application. For example, in the case of a quinacridone solid solution pigment to be used as a colorant of the inkjet ink of the present invention, it is manufactured under the condition that the long-axis particle size is 20 to 80 nm in consideration of discharge stability and the like. In addition, the long-axis particle diameter of the quinacridone solid solution pigment is more preferably about 30 nm. In addition, the above-mentioned long-axis particle diameter is an average value observed by a transmission electron microscope.

<Ink for Inkjet>

The ink-based colorant for inkjet of the present invention contains a long-axis particle diameter of 20 to 80 nm, and has 2θ values of (2θ±0.2°) using Bragg angles (θ) of 27.5° and 13.8° in powder X-ray diffraction. and quinacridone solid solution pigment with a specific diffraction peak of 6.0°. Such a quinacridone solid solution pigment can be easily obtained according to the above-described production method of the present invention. In addition, in order to improve the dispersibility and dispersion stability of the quinacridone solid solution pigment, and the storage stability over time of the ink, the inkjet ink of the present invention contains a pigment dispersant. The pigment dispersant can be suitably used by those using water-based pigment inks for conventionally known inkjets. In addition to these, additives such as surfactants, organic solvents, and moisturizing agents may also be added to the inkjet ink of the present invention as necessary, and known techniques of related inkjet aqueous pigment inks may also be used for these.

The inkjet ink system of the present invention contains a quinacridone solid solution pigment that makes the coloring matter high in chroma and has a moderately yellowish and favorable hue. The addition amount of the quinacridone solid solution pigment is not particularly limited, as long as it is contained within a conventionally known range. Specifically, it is only necessary to contain about 0.5 to 30 mass % in 100 mass % of the ink, more preferably about 4 to 10 mass %. If the addition amount is less than 0.5% by mass, the printing density may not be ensured. On the other hand, if the addition amount exceeds 30% by mass, the viscosity of the ink will increase, and the viscosity characteristics will become structurally viscous, causing the ink to become viscous. When the stability of discharge from the inkjet head is deteriorated.

[Example]

Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples. In addition, the following "%" and "part" are "quality standards" unless otherwise stated.

[Quinacridone Solid Solution Pigment] <Example 1>

In a 100 ml separable flask, 65.6 g of 85% phosphoric acid was weighed, and 98.7 g of phosphoric anhydride was added to prepare 84.0% polyphosphoric acid. When the internal temperature dropped to about 100°C, 6.12 g of 2,5-bis(p-toluidine)terephthalic acid (DM-DATA) was slowly added, and then 2,5-diphenylaminoterephthalic acid (DATA) was slowly added. ) 14.28g. After the addition, the co-cyclization reaction was carried out at 120° C. for 4 hours. After the reaction was completed, the above-mentioned reaction solution was thrown into 400 ml of normal temperature water in a 1L beaker. After filtration and water washing, it was transferred to a 1L beaker, 800 ml of water was added and stirred, and caustic soda was added to adjust the pH to 7~8. It was filtered and washed with hot water to obtain a crude quinacridone solid solution in a water-containing state. The mass ratio of unsubstituted quinacridone to 2,9-dialkylquinacridone in the crude quinacridone solid solution was 7:3.

The crude quinacridone solid solution in a water-containing state obtained as described above was dried at 80° C. overnight so that the moisture content was less than 1%. After drying, pulverization was performed to obtain 18.0 g of a powder of a crude quinacridone solid solution. The obtained powder was observed by a transmission electron microscope, and as a result, the average particle diameter of the long axis was about 20 nm.

Next, the crude quinacridone solid solution was pigmented using dimethyl sulfoxide (DMSO) in a liquid medium in which the powder was not dissolved. Specifically, 7.0 g of the powder of the crude quinacridone solid solution obtained above, and 70.0 g of dimethyl sulfoxide were charged into a 100-ml separable flask, and the temperature was raised to 80° C. over 30 minutes, and the treatment was carried out at the same temperature. 1 hour heat treatment. Then, after cooling to below 70°C, the powder was filtered, washed with hot water and water until the filtrate was colorless, and then dried at 80°C to obtain the powder of the quinacridone solid solution pigment of this example.

It was confirmed by powder X-ray diffraction that the pigment obtained as described above is indeed the objective quinacridone solid solution of the present invention. Specifically, the powder of the quinacridone solid solution pigment to be measured was packed in a predetermined container, and the measurement was performed using a powder X-ray diffraction apparatus mini Flex600 (trade name, manufactured by Rigaku Co., Ltd., and the same apparatus was used in other examples). . As a result, the powder X-ray diffraction of the quinacridone solid solution pigment obtained as described above had spectral peaks at 27.5°, 13.8°, and 6.0° of 2θ values. Also, the peak intensity ratio is about 63:78:100.

Furthermore, when the pigment particles of the quinacridone solid solution pigment obtained above were observed with a transmission electron microscope, the average particle diameter of the long axis was about 30 nm. This is referred to as quinacridone solid solution pigment 1, or simply referred to as solid solution pigment 1. The color evaluation result of the colorant obtained when the quinacridone solid solution pigment 1 was obtained as described above will be described later together with other examples.

<Example 2>

In this example, the powdery crude quinacridone solid solution obtained in Example 1 was used, and it was heated in the presence of a quinacridone-based pigment derivative for pigmentation. Specifically, 7.0 g of the crude quinacridone solid solution powder obtained in Example 1, 70.0 g of dimethylsulfoxide (DMSO) as a liquid medium, and 2-phthalimide group of the quinacridone-based pigment derivative 0.35 g of methyl quinacridone powder was charged into a 100 ml separable flask, and the temperature was raised to 80° C. over 30 minutes, and the treatment was performed at the same temperature for 3 hours. Then, after cooling to below 70°C, it was filtered, washed with hot water and water until the filtrate was colorless, and then dried at 80°C to obtain the powder of the quinacridone solid solution pigment of this example.

It was confirmed by powder X-ray diffraction that the pigment obtained as described above is indeed the objective quinacridone solid solution of the present invention. As a result, there were spectral peaks at 27.5°, 13.8°, and 6.0°, respectively, according to the 2θ value obtained in powder X-ray diffraction. Also, the peak intensity ratio is about 64:77:100. Moreover, in the same manner as in Example 1, the pigment particles were observed with a transmission electron microscope, and as a result, the average particle diameter of the long axis was about 25 nm. This is referred to as quinacridone solid solution pigment 2, or simply referred to as solid solution pigment 2.

<Example 3>

In a 100 ml separable flask, 65.6 g of 85% phosphoric acid was weighed, and 98.7 g of phosphoric anhydride was added to prepare 84.0% polyphosphoric acid. When the internal temperature dropped to about 100°C, 4.08 g of 2,5-bis(p-toluidine)terephthalic acid (DM-DATA) was slowly added, and then 2,5-diphenylaminoterephthalic acid (DATA) was slowly added. ) 16.32g. After the addition, the co-cyclization reaction was carried out at 120° C. for 4 hours. After the reaction was completed, the above-mentioned reaction solution was thrown into 400 ml of normal temperature water in a 1L beaker. After filtration and water washing, it was transferred to a 1L beaker, 800 ml of water was added and stirred, and caustic soda was added to adjust the pH to 7~8. It was filtered and washed with hot water to obtain a crude quinacridone solid solution in a water-containing state. The mass ratio of unsubstituted quinacridone to 2,9-dialkylquinacridone in the crude quinacridone solid solution is 8:2.

The crude quinacridone solid solution in a water-containing state obtained as described above was dried at 80° C. overnight so that the moisture content was less than 1%. After drying, pulverization was performed to obtain 17.9 g of a powder of a crude quinacridone solid solution. The obtained powder was observed by a transmission electron microscope, and as a result, the average particle diameter of the long axis was about 20 nm.

Next, the crude quinacridone solid solution was pigmented in the same manner as in Example 1 to obtain a powder of the quinacridone solid solution pigment of this example.

The pigment obtained as described above has spectral peaks at 2θ values of 27.6°, 13.8° and 6.1° in powder X-ray diffraction, and the peak intensity ratio is about 57:77:100. Moreover, in the same manner as in Example 1, when the pigment particles were observed by a transmission electron microscope, the average particle diameter of the long axis was about 30 nm. This is referred to as quinacridone solid solution pigment 3, or simply referred to as solid solution pigment 3.

<Example 4>

In a 100 ml separable flask, 65.6 g of 85% phosphoric acid was weighed, and 98.7 g of phosphoric anhydride was added to prepare 84.0% polyphosphoric acid. When the internal temperature dropped to about 100°C, 8.16 g of 2,5-bis(p-toluidine)terephthalic acid (DM-DATA) was slowly added, and then 2,5-diphenylaminoterephthalic acid (DATA) was slowly added. ) 12.24g. After the addition, the co-cyclization reaction was carried out at 120° C. for 4 hours. After the reaction was completed, the above-mentioned reaction solution was thrown into 400 ml of normal temperature water in a 1L beaker. After filtration and water washing, it was transferred to a 1L beaker, 800 ml of water was added and stirred, and caustic soda was added to adjust the pH to 7~8. It was filtered and washed with hot water to obtain a crude quinacridone solid solution in a water-containing state. The mass ratio of unsubstituted quinacridone to 2,9-dialkylquinacridone in the crude quinacridone solid solution is 6:4.

The crude quinacridone solid solution in a water-containing state obtained as described above was dried at 80° C. overnight so that the moisture content was less than 1%. After drying, pulverization was performed to obtain 18.1 g of a powder of a crude quinacridone solid solution. The obtained powder was observed by a transmission electron microscope, and as a result, the average particle diameter of the long axis was about 20 nm.

Next, the crude quinacridone solid solution was pigmented in the same manner as in Example 1 to obtain a powder of the quinacridone solid solution pigment of this example.

The pigment obtained as described above has spectral peaks at 27.4°, 13.8° and 5.9° in 2θ value in powder X-ray diffraction, and the peak intensity ratio is about 71:76:100. Moreover, in the same manner as in Example 1, when the pigment particles were observed by a transmission electron microscope, the average particle diameter of the long axis was about 30 nm. This is referred to as quinacridone solid solution pigment 4, or simply referred to as solid solution pigment 4.

<Comparative Example 1>

In a 100 ml separable flask, 65.6 g of 85% phosphoric acid was weighed, and 98.7 g of phosphoric anhydride was added to prepare 84.0% polyphosphoric acid. When the internal temperature dropped to about 100°C, 14.28 g of 2,5-bis(p-toluidine)terephthalic acid (DM-DATA) was slowly added, and then 2,5-diphenylaminoterephthalic acid (DATA) was slowly added. ) 6.12g. After the addition, the co-cyclization reaction was carried out at 120° C. for 4 hours. After the reaction was completed, the above-mentioned reaction solution was thrown into 400 ml of normal temperature water in a 1L beaker. After filtration and water washing, it was transferred to a 1L beaker, 800 ml of water was added and stirred, and caustic soda was added to adjust the pH to 7~8. It was filtered and washed with hot water to obtain a crude quinacridone solid solution in a water-containing state. The mass ratio of unsubstituted quinacridone and 2,9-dialkyl quinacridone in the crude quinacridone solid solution is 3:7, which is beyond the scope of the present invention.

The crude quinacridone solid solution in a water-containing state obtained as described above was dried at 80° C. overnight so that the moisture content was less than 1%. After drying, pulverization was performed to obtain 18.0 g of a powder of a crude quinacridone solid solution. The obtained powder was observed by a transmission electron microscope, and as a result, the average particle diameter of the long axis was about 20 nm.

Next, the crude quinacridone solid solution was pigmented using dimethyl sulfite as a liquid medium in which the powder was not dissolved. Specifically, 7.0 g of the powder of the crude quinacridone solid solution obtained above, and 70.0 g of dimethyl sulfite were charged into a 100-ml separable flask, and the temperature was raised to 105° C. over 1 hour, and the treatment was carried out at the same temperature. 6 hours heat treatment. Then, after cooling to 70°C or lower, the powder was filtered, washed with hot water and water until the filtrate was colorless, and then dried at 80°C to obtain the powder of the quinacridone solid solution pigment of this comparative example.

The pigment obtained as described above has peaks at 27.3°, 13.9°, and 5.6° in 2θ values in powder X-ray diffraction, and it was confirmed that the combination of diffraction peaks differs from that specified in the present invention. Also, the peak intensity ratio is about 75:65:100. In addition, when the pigment particles were observed with a transmission electron microscope, the average particle diameter of the long axis was about 50 nm. This is referred to as Comparative Quinacridone Solid Solution Pigment 1, or simply as Comparative Solid Solution Pigment 1.

<Comparative Example 2>

Two different quinacridone pigments, such as crude unsubstituted quinacridone and crude 2,9-dimethyl quinacridone, were made up of 7:3 in the same mass ratio as the solid solution pigment of Example 1. After mixing, it is pigmented with dimethyl sulfite. Specifically, 7.0 g of the powder of the crude mixed quinacridone and 70.0 g of dimethyl sulfoxide were charged into a 100 ml separable flask, the temperature was raised to 80° C. over 30 minutes, and a heat treatment was performed at the same temperature for 1 hour. . Then, after cooling to below 70°C, the filtrate was filtered, washed with hot water and water until the filtrate was colorless, and then dried at 80°C to obtain a quinacridone pigment which belongs to a mixture of two different quinacridone pigments in this comparative example. powder. In addition, as a result of observing the pigment particles with a transmission electron microscope, the average particle diameter of the long axis was about 30 nm. This is referred to as Comparative Quinacridone Solid Solution Pigment 2, or simply as Comparative Solid Solution Pigment 2.

<Evaluation 1>

Using each of the quinacridone solid solution pigments obtained in Examples 1 to 4 and Comparative Example 1, and the mixed pigment obtained in Comparative Example 2, two kinds of paints obtained respectively as follows were used to prepare primary color coating films and light color coating films. Then, the L ^* a ^* b ^* value was measured for each coating film, and the color tone was evaluated. The results obtained are shown in Table 1.

1. Production of paint (1) Production of primer coating

0.8 g of each pigment of Examples and Comparative Examples, 5.0 g of an alkyd-melamine resin (trade name: 106-3700 Rukaclear artclear (trade name); manufactured by Isamu Paint Co., Ltd.), and the main components were toluene, ethyl acetate, and butyl 5.0 g of an alcohol thinner (trade name: NIPPE 2500 thinner (trade name); manufactured by Nippon Paint Co., Ltd.) and 50.0 g of glass beads were placed in a plastic container. Then, after dispersing this mixture with a paint shaker for 1 hour, 35.0 g of the above-mentioned alkyd-melamine resin and 4.0 g of the above-mentioned diluent were added and dispersed for 10 minutes to obtain a dispersion liquid of each pigment. 10.0 g of each of the obtained dispersions and 20.0 g of the above-mentioned alkyd-melamine resin were placed in a plastic container, and dispersed and mixed with a planetary mixer (trade name, manufactured by KURABO Corporation) to obtain primer paints containing each pigment.

(2) Production of light-colored paint

0.8 g of each of the pigments of Examples and Comparative Examples, 5.0 g of the above-mentioned alkyd-melamine resin, 5.0 g of the above-mentioned diluent, and 50 g of glass beads were placed in a plastic container. Then, after this mixture was dispersed for 1 hour with a paint shaker, 35.0 g of the above-mentioned alkyd-melamine resin and 4.0 g of the above-mentioned diluent were added and dispersed for 10 minutes to obtain a dispersion liquid of each pigment. 10.0 g of each of the obtained dispersions and 20.0 g of white ink mainly composed of titanium oxide (trade name: 10 Super 300 White (trade name); manufactured by Nippon Paint Co., Ltd.) were placed in a plastic container, and a planetary mixer was used. Dispersion mixing is performed to form a light-colored paint containing each pigment.

2. Production of color exhibit and evaluation of hue

(1) The prepared primer coating was developed on the development paper using a 6mil dripper. The development paper was dried at room temperature for several hours. The color development paper (hereinafter also referred to as primary color coating film) produced in this way using the paints containing the respective pigments of the Examples and Comparative Examples was subjected to comparative evaluation of the hue by visual observation and using a colorimeter. The results are shown in Table 1. In addition, the visual observation is a relative evaluation.

(2) Using a 6 mil dripper to develop the produced light color paint on a development paper, the development paper was dried at room temperature for several hours. Evaluation was performed similarly to the above about the hue of the colored development paper (henceforth also called a light color coating film) obtained in this way. The results are shown in Table 1.

求取。 (3) For the primary color coating films and light color coating films of Examples 1 to 4 and Comparative Examples 1 and 2 produced as described above, color measurement was performed using a color measuring machine, respectively. The color measurement values are shown in Table 1. At this time, color measurement was performed using a spectrophotometer CM-3600d (trade name, manufactured by Konica Minolta). L ^* is lightness, C ^* is chroma, and C ^* is chroma

ask for.

The difference between Example 1 and Comparative Example 1 is: only in the mass ratio of unsubstituted quinacridone and 2,9-dialkyl quinacridone, but as shown in Table 1, it is particularly found that the b ^* value appears larger. difference. Although the visual observation results are consistent, the smaller the b ^* value is, the more the blue is shifted, resulting in a more bluish hue. If the b ^* value is larger, the more yellowish the hue is. The solid solution pigments obtained in other examples were also confirmed to have a large b ^* value and a yellowish hue. In addition, in the case of Comparative Quinacridone Pigment 2 of Comparative Example 2, which was composed of a mixture of two kinds of quinacridone pigments, although the hue was yellowish, it was confirmed that the vividness when visually observed was significantly inferior to the case of the Examples. .

[Ink for Inkjet] <Preparation of Magenta Aqueous Pigment Dispersion Liquid 1>

The quinacridone solid solution pigment obtained in Example 1 of the magenta pigment is 1:200 parts, 200 parts of pigment dispersant, and diethylene glycol monobutyl ether (also known as butyl diethylene glycol, hereinafter referred to as the liquid medium). BDG) 30 parts and 340 parts of water were blended, and the pre-grinding base was prepared by performing degumming using a disperser. The above-mentioned pigment dispersant is an aqueous solution of ammonia neutralization product using a number-average molecular weight of 7000, an acid value of 155 mgKOH/g, and a copolymer of styrene/acrylic acid-2-ethylhexyl/acrylic acid (mass ratio: 50/30/20). 30% solids). Next, the obtained pre-milled base was used a horizontal media disperser "bead mill 0.6 liter ECM type" (trade name, manufactured by SHINMARU ENTERPRISES, zirconium dioxide ball diameter 0.3 mm), at a peripheral speed of 7 m/ s implement decentralized processing. Dispersion was completed after 1 hour of dispersion to obtain a mill base.

The obtained grinding base was diluted with ion-exchanged water to a state of 15% of the pigment content, followed by centrifugal separation treatment to obtain a pigment dispersion liquid composed of quinacridone solid solution pigment 1 dispersed. Then, the obtained pigment dispersion liquid was filtered through a 10 μm membrane filter, and predetermined amounts of ion-exchanged water, preservatives, and glycerin were added to obtain a magenta pigment dispersion liquid 1 having a pigment concentration of 12%.

The magenta pigment dispersion liquid 1 obtained above was measured (25°C) for the average particle diameter by a particle size analyzer "NICOMP 380ZLS-S" (particle size measuring system, manufactured by PSS Corporation), and the average particle diameter was 126 nm. In addition, the viscosity is 4.03 mPa·s, the surface tension is 44.0 mN/m, and the pH is 9.6. In Table 2, the formula and physical property results of the magenta pigment dispersion liquid 1 are collectively indicated.

<Preparation of magenta aqueous pigment dispersion liquid 2~6>

In addition to replacing the quinacridone solid solution pigment 1 used in the production of the magenta water-based pigment dispersion 1, the quinacridone solid solution pigments 2 to 4 obtained in the examples and comparative examples were used instead. Except for the solution pigment 1 and the comparison quinacridone pigment 2, the rest were in accordance with the magenta aqueous pigment dispersion liquid 1, and the magenta pigment dispersion liquids 2 to 6 were obtained. In Table 2, the formulations and physical properties of the pigment dispersions 2 to 6 are indicated overall.

<Magenta inkjet water-based pigment ink 1~6 production>

Next, using the magenta aqueous pigment dispersion liquid 1 obtained above, to this aqueous pigment dispersion liquid 1: 41.7 parts, BDG: 5.0 parts, triethylene glycol monobutyl ether (BTG): 2.5 parts, glycerin 18 parts, "SURFYNOL 465" (trade name, manufactured by Air Products Co., Ltd.) 1 part, and water, adjust the total amount to a state of 100 parts, and stir well. Then, filtration was performed with a membrane filter having a pore size of 10 μm to remove large pigment particles, thereby obtaining aqueous pigment ink 1 for magenta inkjet.

The particle size of the pigment in the obtained ink was measured as an average particle size (25°C) using a particle size analyzer "NICOMP 380ZLS-S" (trade name, particle size measurement system, manufactured by PSS Corporation), and the result was 124 nm, and the ink viscosity was 3.41 mPa·s, pH 9.5. The particle size of the pigment in the ink is the average particle size value based on the scattered light intensity measured by a particle size analyzer "NICOMP 380ZLS-S". In addition, the ink viscosity is the value measured by the particle size measuring apparatus "NICOMP 380ZLS-S".

Aqueous pigment inks 2 to 6 for magenta inkjet were produced in the same manner as above, except that aqueous pigment dispersions 2 to 6 were used instead of aqueous pigment dispersion 1. Table 3 summarizes the physical properties of the prepared inks.

<Evaluation 2: Evaluation of Pigment Dispersion Liquid and Ink> 1. Evaluation of dispersion stability and storage stability

For the magenta aqueous pigment dispersions 1 to 6 and the magenta inkjet aqueous pigment inks 1 to 6 prepared above, the viscosity and particle size were measured at the initial stage and at 70° C. for 7 days, respectively. Using these measured values, the viscosity change rate (%) and the particle size change rate (%) were calculated, respectively, and the dispersion stability and storage stability of the ink were evaluated according to the following criteria. In addition, the change rate was calculated|required from the percentage (%) of (value after 7 days)/(initial value)-1, and the result obtained is shown in Table 4.

[Evaluation Criteria] (Particle size change)

A: The particle size change rate is less than ±5%

B: The particle size change rate is ±5% or more and less than 10%

C: The particle size change rate is ±10% or more and less than 15%

D: The particle size change rate is more than ±15%

(viscosity change)

A: The initial viscosity is low and the change rate is less than ±10%

B: The initial viscosity is high, and the change rate is less than ±10%

C: The initial viscosity is low, and the change rate is more than ±10%

D: The initial viscosity is high, and the change rate is more than ±10%

In addition, the viscosity "over 4mPa·s" was set as "high viscosity", and the "less than 4mPa·s" was set as "low viscosity".

(Quality Evaluation of Printed Matter)

Fill the ink cartridges with the magenta inkjet water-based pigment inks 1 to 6 produced as described above, and use an inkjet printer in the photo mode on (i) photo-specific glossy paper (PGPP), and (ii) Printing is performed on two types of paper, such as plain paper, to obtain prints respectively. As an inkjet printer, "PM4000PX" (trade name, manufactured by Seiko Epson Corporation) was used. In addition, as the plain paper, "Xerox Business 4200 paper" (trade name, manufactured by Xerox, USA) was used. As a result, it was confirmed that any of the aqueous pigment inks could be discharged from the nozzles of the inkjet without any problems.

The quality of the obtained printed matter was evaluated using a spectrophotometer "i1 basic Pro" (trade name, manufactured by X-rite Corporation). Specifically, the chromaticity C ^* and the optical density (OD value) were measured and evaluated under the following conditions using a spectrophotometer for each obtained printed matter. However, the measurement results are shown in Table 5. In addition, the results of color tone observation by visual observation are combined and displayed. In addition, both the optical density (OD value) and the chroma C ^* can be evaluated that the larger the numerical value, the better.

[Measurement conditions]

Plain paper optical density (OD value): average value of 3 measurements at 6 locations

Optical properties of plain paper (chromaticity C ^* ): average value of 1 measurement at 6 locations

Density (OD value) of glossy paper for photo: average value of 1 measurement at 3 locations

Characteristics of glossy paper for photographic use (chroma C ^* ): average value of 1 measurement at 3 locations

From the results shown in Table 5, it can be seen that the printed matter printed by the water-based pigment ink 1 for magenta inkjet using the quinacridone solid solution pigment 1 of Example 1 is on plain paper and glossy paper. When any one of them is printed, compared with the magenta inkjet water-based pigment ink 6 using the PV19 pigment and PR122 mixed pigment of Comparative Example 2 obtained according to the conventional manufacturing method, the obtained print material has the former's hair color. Both chromaticity (OD value) and chroma (C ^* ) were excellent. In addition, as a result of visual observation of the printed matter, the printed matter printed by the water-based pigment ink 1, compared with the printed matter printed by the water-based pigment ink 5 of the comparative example 1, it can be confirmed that the former is significantly Has a yellowish phase. From this, it can be seen that by using the quinacridone solid solution pigment obtained by the production method of the present invention, the obtained printed matter is confirmed to be able to maintain the chroma and chroma at a high level compared with the conventional printed matter. The printing density is excellent, and the color development is excellent. At the same time, it has the inkjet characteristics that can fully meet the requirements of the market to form images with a yellowish phase.

Claims (9)

A manufacturing method of a quinacridone solid solution pigment, comprising: a manufacturing step of a crude quinacridone solid solution, a drying step of drying the crude quinacridone solid solution, and a drying step of the crude quinacridone solid solution The pigmentation step of heating in a solvent to make a pigment; it is characterized in that the production step of the above-mentioned crude quinacridone solid solution is in polyphosphoric acid, and diarylamine terephthalic acid and dialkylarylamine terephthalic acid are prepared Carry out a co-cyclization reaction to obtain a crude quinacridone solid in a water-containing state containing water in a solid solution with a mass ratio of 85:15 to 60:40 of unsubstituted quinacridone and 2,9-dialkyl quinacridone. solution; the above-mentioned drying step is to dry the crude quinacridone solid solution according to the above-mentioned water-containing state, so that the moisture content is less than 1%, to obtain a powdery crude quinacridone solid solution; the above-mentioned pigmentation step is to dry the above-mentioned powder The crude quinacridone solid solution in the form of a solid solution is heated in a liquid medium that does not dissolve the crude quinacridone solid solution; ) of the (2θ±0.2°) 2θ value is the specific diffraction peak at 27.5°, 13.8° and 6.0°, when the above-mentioned 6.0° spectrum peak intensity is set as 100, the 13.8° spectrum peak intensity ratio is 70~80, The 27.5° peak intensity ratio is 55~71. The method for producing a quinacridone solid solution pigment of claim 1, wherein the diarylamino terephthalic acid is 2,5-diphenylamino terephthalic acid; the dialkylarylamino terephthalic acid is 2,5-diphenylamino terephthalic acid; 5-bis(p-toluidine)terephthalic acid. The method for producing a quinacridone solid solution pigment according to claim 1 or 2, wherein the pigmentation step is to heat the powdery crude quinacridone solid solution in the liquid medium to make the quinacridone Pigment derivatives exist. The method for producing a quinacridone solid solution pigment according to claim 3, wherein the quinacridone The ketone-based pigment derivative is 2-phthalimidomethylquinacridone. The method for producing a quinacridone solid solution pigment according to claim 1 or 2, wherein the liquid medium that does not dissolve the crude quinacridone solid solution is dimethyl sulfite. The method for producing a quinacridone solid solution pigment according to claim 5, wherein the heating temperature in the pigmentation step is 60°C or higher and 120°C or lower. As claimed in claim 1 or 2, the method for producing a quinacridone solid solution pigment is for obtaining a quinacridone solid solution pigment with a long-axis particle diameter of 20 to 80 nm. A pigment dispersion liquid containing: a quinacridone solid solution pigment of unsubstituted quinacridone and 2,9-dialkyl quinacridone, a pigment dispersant and water; it is characterized in that the above-mentioned quinacridone solid solution In powder X-ray diffraction, the body pigment has specific diffraction peaks of 27.5°, 13.8° and 6.0° using the Bragg angle (θ) of (2θ±0.2°), and the above-mentioned 6.0° spectrum peak When the intensity is set to 100, the 13.8° peak intensity ratio is 70~80, and the 27.5° peak intensity ratio is 55~71. A kind of inkjet ink, which is composed of: quinacridone solid solution pigment, pigment dispersant and water inkjet ink; the quinacridone solid solution pigment is composed of unsubstituted quinacridone and 2,9-diol The solid solution composition of alkyl quinacridone, and the long-axis particle diameter is 20~80nm; It is characterized in that, the above-mentioned quinacridone solid solution pigment is in powder X-ray diffraction, and has a Bragg angle (θ) of ( 2θ±0.2°) are specific diffraction peaks with 2θ values of 27.5°, 13.8° and 6.0°. When the above-mentioned 6.0° spectrum peak intensity is set to 100, the 13.8° spectrum peak intensity ratio is 70~80, 27.5° spectrum The peak intensity ratio was 55-71.