Naphthol-based azo pigment, coloring composition, and method for producing naphthol-based azo pigment

Abstract

To provide a naphthol-based azo pigment that has superior dispersibility and dispersion stability and exhibits high coloring power and weather resistance, and to provide a method for producing the naphthol-based azo pigment.SOLUTION: A naphthol-based azo pigment represented by the following general formula, has an average primary particle diameter of 90 nm or more and 1000 nm or less, and an average aspect ratio of the primary particles of 1 or more and 3.3 or less. [In the formula, R1 represents H, an alkyl group, a halogen group, a nitro group, a carboxyl group, or the like; R2 and R3 each independently represent H, an alkoxy group, an alkyl group, a halogen group, a nitro group, or the like; one of X1 and X2 is a carboxyl group or a carbamoyl group; and at least one of Y1 to Y3 is an alkoxy group or a halogen group, and the remainder is H.]SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to naphthol-based azo pigments. [Background technology]

[0002] Architectural signs, outdoor signs, paints, etc. are used outdoors for long periods of time, so the pigments used for coloring them must have excellent resistance to heat, light, water, etc. (hereinafter collectively referred to as weather resistance). Among pigments, quinacridone pigments are red pigments with hues ranging from red to magenta and have excellent weather resistance, and Patent Document 1 discloses a printing ink using a quinacridone pigment. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-050818 Summary of the Invention [Problem to be solved by the invention]

[0004] However, quinacridone pigments have good heat resistance and color clarity, but are expensive and have the drawback of poor coloring power and dispersion stability, while naphthol azo pigments, which are classified as insoluble azo pigments, have high coloring power and a good balance between production cost and fastness, but have the problem of insufficient weather resistance.

[0005] An object of the present invention is to provide a naphthol-based azo pigment that is excellent in dispersibility and dispersion stability, and has high tinting power and weather resistance. [Means for solving the problem]

[0006] <1> The present invention provides a naphthol-based azo pigment, which is a compound represented by the following general formula (1) having an average primary particle diameter of 90 nm or more and 1000 nm or less and an average primary particle aspect ratio of 1 or more and 3.3 or less, and which satisfies the following condition 1 or 2: General formula (1) [ka]

[0007] [In general formula (1), R1 is a hydrogen atom, an alkyl group, a halogen group, a nitro group, a carboxy group, a sulfo group, a phosphate group, a sulfamoyl group, a carbamoyl group, an alkylsulfamoyl group, or an alkylcarbamoyl group. R2 and R3 are each independently a hydrogen atom, an alkoxy group, an alkyl group, a halogen group, a nitro group, a carboxy group, a sulfo group, a phosphate group, a sulfamoyl group, a carbamoyl group, an alkylsulfamoyl group, or an alkylcarbamoyl group. Condition 1: Either X1 or X2 is a carboxy group or a carbamoyl group, at least one of Y1, Y2, and Y3 is an alkoxy group or a halogen group, and the remainder of X1, X2, Y1, Y2, and Y3 are hydrogen atoms. Condition 2: Either X1 or X2 is an alkoxy group or a halogen group, at least one of Y1, Y2, and Y3 is a carboxy group or a carbamoyl group, and the remainder of X1, X2, Y1, Y2, and Y3 are hydrogen atoms. <2> R1 is a hydrogen atom or an alkyl group, and R2 and R3 are hydrogen atoms. <1> Naphthol-based azo pigment. <3> <1> or <2> A coloring composition comprising the naphthol azo pigment of the formula (I) and a dispersion medium. <4> <1> or <2> A paint comprising the naphthol azo pigment of the formula (I), a resin, and a solvent. <5> <1> or <2> An ink comprising the naphthol azo pigment of the formula (I), a resin, and a solvent. <6> <1> or <2> and a polymerizable compound. <7> <1> A method for producing a naphthol azo pigment according to claim 1, A method for producing a naphthol-based azo pigment, comprising: subjecting a solution containing a coupler component represented by the following general formula (2) to a coupling reaction with a solution containing a diazonium salt represented by the following general formula (4) obtained by diazotizing an aromatic amine represented by the following general formula (3) in the presence of a water-soluble organic solvent, to obtain a compound represented by the general formula (1). [ka]

[0008] [In general formula (2), general formula (3) and general formula (4), R1 is a hydrogen atom, an alkyl group, a halogen group, a nitro group, a carboxy group, a sulfo group, a phosphate group, a sulfamoyl group, a carbamoyl group, an alkylsulfamoyl group or an alkylcarbamoyl group. R2 and R3 are each independently a hydrogen atom, an alkoxy group, an alkyl group, a halogen group, a nitro group, a carboxy group, a sulfo group, a phosphate group, a sulfamoyl group, a carbamoyl group, an alkylsulfamoyl group, or an alkylcarbamoyl group. [Z n- ] 1 / n is an anion of any valence n (n is an integer from 1 to 3). X1, X2, Y1, Y2, and Y3 satisfy either condition 1 or condition 2 below. Condition 1: Either X1 or X2 is a carboxy group or a carbamoyl group, at least one of Y1, Y2, and Y3 is an alkoxy group or a halogen group, and the remainder of X1, X2, Y1, Y2, and Y3 are hydrogen atoms. Condition 2: Either X1 or X2 is an alkoxy group or a halogen group, at least one of Y1, Y2, and Y3 is a carboxy group or a carbamoyl group, and the remainder of X1, X2, Y1, Y2, and Y3 are hydrogen atoms. [Effects of the Invention]

[0009] According to the present invention, a naphthol-based azo pigment having excellent dispersibility and dispersion stability, as well as high tinting strength and weather resistance, can be provided. The present invention also provides a coloring composition, a paint, an ink, an actinic energy ray-curable ink, and the like. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional side view of an apparatus for producing an evaluation sheet according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, the embodiments of the present invention will be described in more detail. However, the present invention is not limited to the following embodiments, and various modifications may be made within the scope of the present invention, and various embodiments are included. In this specification, the aspect ratio is the value obtained by dividing the major axis of a particle by the minor axis.

[0012] <1> Naphthol-based azo pigments A naphthol-based azo pigment according to an embodiment of the present invention is a compound represented by the following general formula (1), which has an average primary particle diameter of 90 nm or more and 1000 nm or less and an average primary particle aspect ratio of 1 or more and 3.3 or less. The compound represented by general formula (1) satisfies the following condition 1 or condition 2: General formula (1) [ka]

[0013] [In general formula (1), R1 is a hydrogen atom, an alkyl group, a halogen group, a nitro group, a carboxy group, a sulfo group, a phosphate group, a sulfamoyl group, a carbamoyl group, an alkylsulfamoyl group, or an alkylcarbamoyl group. R2 and R3 are each independently a hydrogen atom, an alkoxy group, an alkyl group, a halogen group, a nitro group, a carboxy group, a sulfo group, a phosphate group, a sulfamoyl group, a carbamoyl group, an alkylsulfamoyl group, or an alkylcarbamoyl group. Condition 1: Either one of X1 and X2 is a carboxy group or a carbamoyl group, at least one of Y1, Y2 and Y3 is an alkoxy group or a halogen group, and the remainder of X1, X2, Y1, Y2 and Y3 are hydrogen atoms. Condition 2: Either one of X1 and X2 is an alkoxy group or a halogen group, at least one of Y1, Y2, and Y3 is a carboxy group or a carbamoyl group, and the remaining ones of X1, X2, Y1, Y2, and Y3 are hydrogen atoms.

[0014] When the naphthol azo pigment of this specification satisfies condition 1 or condition 2, the substituent X1 or X2 of the molecule of general formula (1) forms an intermolecular hydrogen bond with the substituents Y1 to Y3 of the adjacent molecule, thereby enhancing chemical stability. This is thought to enable the molecular structure to be maintained even when used for long periods in harsh outdoor environments, thereby providing weather resistance. Furthermore, by setting the aspect ratio of the naphthol-based azo pigment particles to 1 or more and 3.3 or less, the particle shape becomes nearly spherical, allowing for uniform interparticle distances (reaching a suitable interparticle distance). This suppresses particle aggregation, making it difficult for the viscosity to increase when preparing a coloring composition. Furthermore, it is possible to suppress viscosity increases due to particle aggregation during long-term storage of the coloring composition. Additionally, an average primary particle diameter of the particles of 90 nm or more and 1000 nm or less can achieve both dispersibility and weather resistance in addition to coloring power.

[0015] In general formula (1), the "alkyl group" may have 1 to 8 carbon atoms and may have any of a linear structure, a branched structure, and a cyclic structure. In one embodiment, the alkyl group preferably has a linear structure. The number of carbon atoms in the alkyl group is preferably 1 to 4, more preferably 1 or 2, and even more preferably 1.

[0016] The "halogen group" includes a fluorine atom, a chlorine atom, or a bromine atom. In one embodiment, a chlorine atom or a fluorine atom is preferred, and a chlorine atom is more preferred.

[0017] The "alkyl" in the "alkylsulfamoyl group" is the same as the alkyl group described above. The same applies to the "alkyl" in the "alkylcarbamoyl group". Although not particularly limited, in one embodiment, the alkyl groups in the alkylsulfamoyl group and the alkylcarbamoyl group are each independently preferably alkyl groups having 1 to 4 carbon atoms.

[0018] The "alkoxy group" may have 1 to 8 carbon atoms and may have any of a linear, branched, or cyclic structure. In one embodiment, the alkoxy group preferably has a linear structure. The alkoxy group preferably has 1 to 4 carbon atoms, more preferably 1 or 2, and even more preferably 1.

[0019] The naphthol azo pigment of the present invention has an average aspect ratio of primary particles of 1 or more and 3.30 or less. The aspect ratio is preferably 1 or more and 3.11 or less, and more preferably 1 or more and 3 or less. It is presumed that an aspect ratio of 1 or more and 3.3 or less results in pigment particle shapes that are close to spherical, allowing for uniform interparticle distances, thereby suppressing particle aggregation. This is because an aspect ratio within this range can suppress viscosity increases during pigment dispersion and viscosity increases due to particle aggregation during long-term storage. It is not necessary for the aspect ratios of all particles to be within the above range; it is sufficient that the average ratio of the major axis to the minor axis is within the above range. Primary particle size is measured as described below.

[0020] The naphthol azo pigment of the present invention is characterized in that the average major axis of the pigment's primary particles (hereinafter sometimes referred to as "average primary particle diameter") is 90 nm or more and 1,000 nm or less. The average primary particle diameter of the naphthol azo pigment is preferably 700 nm or less, more preferably 503 nm or less, and even more preferably 352 nm or less. The average primary particle diameter can be determined by calculating the average of the longer diameters of approximately 50 primary pigment particles extracted from multiple photographs taken with a transmission electron microscope at 10,000x magnification. Having the average primary particle diameter of compound (A) within the above range ensures that not only tinting power but also dispersibility and weather resistance are compatible. Details of the methods for measuring the major and minor axes of the primary particles and calculating the average values ​​are provided in the Examples.

[0021] In one embodiment, the naphthol azo pigment is represented by general formula (1), where R1 is a hydrogen atom or an alkyl group, and R2 and R3 are preferably hydrogen atoms. The naphthol azo pigment of the present invention can be used in combination with two or more compounds represented by general formula (1) having different substituents.

[0022] In still another embodiment, the naphthol azo pigment may further contain other components, such as a resin and / or a surfactant used for surface modification during production of the naphthol azo pigment, as long as the other components can solve the problem.

[0023] In one embodiment, the content of the resin is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 1 to 5 parts by mass, relative to 100 parts by mass of the pigment. The content of the surfactant is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, and even more preferably 1 to 3 parts by mass, relative to 100 parts by mass of the pigment.

[0024] <2> Pigment manufacturing method The naphthol-based azo pigment of the compound represented by general formula (1) in the above embodiment can be synthesized by a coupling reaction between a base component and a coupler component in the presence of a water-soluble organic solvent. Specifically, an aromatic amine represented by the following general formula (3) is diazotized as the base component to synthesize a solution (1) containing a diazonium salt represented by the following general formula (4). Separately, a solution (2) containing a coupler component represented by general formula (2) is prepared. Next, these solutions (1) and (2) are mixed to carry out a coupling reaction between the diazonium salt and the coupler component. At least one of the solutions (1) containing the diazonium salt and the solution (2) containing the coupler component contains a water-soluble organic solvent. In one embodiment, it is preferable that at least the solution containing the coupler component contains a water-soluble organic solvent. This produces pigment particles with an average primary particle diameter of 90 nm to 1000 nm and an average primary particle aspect ratio of 1 to 3.3.

[0025] [ka]

[0026] In the above general formulas (2), (3), and (4), R1 to R3, X1, X2, and Y1 to Y3 are as already explained. [Z n- ] 1 / n is an anion of any valence n (n is an integer of 1 to 3). Any anion can be used as long as the diazonium salt is stable and soluble in water, but chloride ion, bromide ion, nitrate ion, nitrite ion, acetate ion, sulfate ion, and phosphate ion are preferred.

[0027] The solution containing the coupler component contains the coupler component, a base, and water, and may further contain a water-soluble organic solvent as needed. The solution containing the coupler component is prepared, for example, by dissolving the coupler component in a heated basic aqueous solution. Alternatively, the solution can be prepared by mixing water, a water-soluble organic solvent, the coupler component, and a base at room temperature (approximately 10°C to 30°C) and dissolving the coupler component and the base. The dissolution temperature can be adjusted depending on the type and amount of the water-soluble organic solvent, the amount of water, and the type and amount of the base to be added. For example, when the solution contains a water-soluble organic solvent, the temperature is preferably about 15 to 50°C. When the solution does not contain a water-soluble organic solvent, the temperature is preferably 50 to 95°C.

[0028] The base is, for example, a compound that dissolves in water and dissolves the coupler component. Furthermore, a base that does not form an insoluble salt when neutralized with an acid in an aqueous acid solution or a solution containing a diazonium salt, which will be described later, is preferred. Such a base is advantageous in terms of cost, dissolving power of the coupler component, waste liquid treatment, etc. The base is preferably, for example, sodium hydroxide or potassium hydroxide.

[0029] The solution containing the diazonium salt contains a diazonium salt and water. The solution containing the diazonium salt may contain a reaction mixture of a base component used in preparing the diazonium salt, an acid component, and aqueous sodium nitrite. Diazonium salts can be obtained by diazotizing the base component of the general formula (3) above. Known methods can be used for diazotization. For example, hydrochloric acid or sulfuric acid is added to a solution of the base component slurried in ice water, and the solution is dissolved, followed by the addition of sodium nitrite to perform diazotization. Sulfamic acid may be added to eliminate excess sodium nitrite used for diazotization. A water-soluble organic solvent may also be added to the solution containing the diazonium salt.

[0030] The water-soluble organic solvent that can be used in the coupling reaction is not particularly limited. The water-soluble organic solvent may be any organic solvent that is miscible with water. The water-soluble organic solvent may be used to obtain a solution containing a coupler component and / or a solution containing a diazonium salt. Examples of water-soluble organic solvents include aprotic polar solvents such as acetonitrile, dimethyl sulfoxide, N,N-dimethylformamide, and N-methyl-2-pyrrolidone; ketones such as acetone and methyl ethyl ketone; cyclic ethers such as tetrahydrofuran and 1,4-dioxane; dihydric alcohols such as ethylene glycol, diethylene glycol, and polyethylene glycol; and monohydric alcohols such as methanol, ethanol, and isopropanol.

[0031] The water-soluble organic solvent may be one of the above solvents used alone or a combination of two or more of them. Although not particularly limited, the water-soluble organic solvent is preferably one or more selected from the group consisting of aprotic polar solvents, ketones, monohydric alcohols, and cyclic ethers. Furthermore, the boiling point of the water-soluble organic solvent is preferably 100°C or lower. Such water-soluble organic solvents with a boiling point of 100°C or lower are advantageous in terms of solvent recovery from waste liquid. For example, one or more selected from the group consisting of acetonitrile, acetone, methyl ethyl ketone, methanol, and isopropanol are preferred.

[0032] The amount of water-soluble organic solvent added can be adjusted depending on the type of water-soluble organic solvent. In one embodiment, when a water-soluble organic solvent is added to either the solution containing the coupler component or the solution containing the diazonium salt, the amount added is preferably 3% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on 100% by mass of the total of water and water-soluble organic solvent contained in the slurry after coupling. The amount is also preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less.

[0033] Examples of the coupling method include reverse coupling, forward coupling, acid precipitation forward coupling, etc. Among these, reverse coupling, which will be described later, is preferred from the viewpoints of particle size control and reaction yield.

[0034] The reverse coupling can be carried out by a known method. For example, a method of adding a solution containing a coupler component to a solution containing a diazonium salt can be used. The temperature during coupling is preferably 0 to 50°C. From the viewpoints of preventing alteration and decomposition of the diazonium salt and of reaction rate, a temperature of 10 to 30°C is particularly preferred.

[0035] A buffer solution may be added to the solution containing the diazonium salt beforehand. The type of buffer solution is not particularly limited, and any buffer solution with buffering capacity may be used. For example, an aqueous solution of acetic acid and sodium acetate is preferred. When adding a buffer solution, it is desirable to adjust the pH of the solution containing the diazonium salt to a range of 3.0 to 6.5. To improve the reaction rate and dispersibility, the slurry after coupling may be heated as needed. The heating temperature is preferably 50°C to 100°C.

[0036] The naphthol azo pigment slurry obtained by the coupling reaction can be filtered using a known suction filter, filter press, ultrafilter, or the like to remove water, solvent, water-soluble salts, etc. In this manner, a pigment press cake is obtained. The pigment press cake can be washed with water, an organic solvent, or other solvent, as needed. The pigment press cake can be used as is to produce a coloring composition. A powder pigment can be produced by drying and pulverizing the pigment according to known methods.

[0037] In one embodiment, well-known techniques for producing naphthol azo pigments can be applied to produce the pigment. For example, when producing the pigment, components well known to those skilled in the art may be used in addition to the pigment raw materials, as needed. For example, well-known components such as resins and / or surfactants may be used to be present in the pigment.

[0038] If components such as resins and / or surfactants are used during the production of pigments, they remain on the pigment surface after production. Therefore, it is preferable that the resins and surfactants be hydrophilic or soluble in base. The use of such resins and surfactants can improve dispersibility by reducing pigment aggregation and impart affinity to the dispersing resin and solvent selected for various applications. Furthermore, the use of these components can also improve reactivity by promoting the dissolution of coupler components and inhibit pigment crystal growth.

[0039] Examples of the resin include styrene-(meth)acrylic acid copolymers, (meth)acrylic acid-(meth)acrylic acid alkyl ester copolymers, styrene-(meth)acrylic acid-(meth)acrylic acid alkyl ester copolymers, styrene-α-methylstyrene-(meth)acrylic acid copolymers, styrene-α-methylstyrene-(meth)acrylic acid-(meth)acrylic acid alkyl ester copolymers, polyacrylic acid, polymethacrylic acid, vinylnaphthalene-(meth)acrylic acid copolymers, styrene-maleic acid (anhydride) copolymers, maleic acid-maleic anhydride copolymers, vinylnaphthalene-maleic acid (anhydride) copolymers, α-olefin-maleic acid (anhydride) copolymers, α-olefin-maleic acid alkyl ester copolymers, and resins having acid groups such as polyester-modified acrylic acid polymers, acrylic copolymers, and salts thereof. The resins may be used alone or in combination of two or more.

[0040] When the resin is used, a compound capable of forming a salt with the resin can be further used, such as a basic compound such as an inorganic base or an organic base. Examples of inorganic bases include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; alkali metal salts of silicic acid such as sodium orthosilicate, sodium metasilicate, and sodium sesquisilicate; alkali metal salts of phosphoric acid such as trisodium phosphate; alkali metal salts of carbonate such as disodium carbonate, sodium hydrogencarbonate, and dipotassium carbonate; alkali metal salts of boric acid such as sodium borate; and ammonia.

[0041] Examples of organic bases include alkylamines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, and triethylamine; alkanolamines such as aminoethanol, methylaminoethanol, dimethylaminoethanol, ethylaminoethanol, butylaminoethanol, diethylaminoethanol, dibutylaminoethanol, diethanolamine, and triethanolamine; and amines having a nonionic group such as methoxypoly(oxyethylene / oxypropylene)-2-propylamine. The basic compounds may be used singly or in combination of two or more.

[0042] In yet another embodiment, surfactants can be used in the preparation of the pigment, including, for example, anionic, nonionic, or amphoteric surfactants.

[0043] Examples of anionic surfactants include fatty acid salts, alkyl sulfate ester salts, alkylaryl sulfonates, alkylnaphthalenesulfonates, alkyl sulfates, dialkylsulfonates, dialkylsulfosuccinates, alkyl diaryl ether disulfonates, alkyl phosphates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkylaryl ether sulfates, naphthalenesulfonate-formalin condensates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phosphate ester salts, glycerol borate fatty acid esters, and polyoxyethylene glycerol fatty acid esters.

[0044] Examples of amphoteric surfactants include betaine, sulfobetaine, alkylbetaine, and alkylamine oxide.

[0045] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, polyoxyethylene oxypropylene block copolymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, and polyoxyethylene alkylamines.

[0046] In one embodiment, the surfactant is preferably an amphoteric surfactant or an anionic surfactant. Although not particularly limited, when the surfactant is added to a solution containing the coupler components, an anionic or amphoteric surfactant is preferred. When the surfactant is added to a slurry obtained after the coupling reaction, a nonionic surfactant may be used. The surfactants may be used alone or in combination of two or more.

[0047] <3> coloring composition One embodiment of the present invention is a coloring composition comprising the naphthol-based azo pigment and a dispersion medium. The dispersion medium comprises at least one compound selected from the group consisting of a resin and a polymerizable compound. The dispersion medium may further comprise a solvent.

[0048] The dispersion medium is selected depending on the application of the coloring composition. In one embodiment, the coloring composition includes a pigment and a resin, and may further include a solvent as needed. In another embodiment, the coloring composition includes a pigment and a polymerizable compound, and may further include at least one of a resin and a solvent as needed. The coloring compositions of the above embodiments may each include various additives as needed. Examples of applications of the coloring composition include pigment dispersions, resin colored materials, paints, and printing inks. Other examples include printed materials, coated materials, and resin molded products colored with the pigment dispersions, resin colored materials, paints, and inks. More specific embodiments of the coloring composition will be described below.

[0049] <Pigment dispersion> In one embodiment, the coloring composition may be in the form of a pigment dispersion containing the pigment of the above embodiment as a main component and further containing a dispersion medium for dispersing the pigment. The dispersion medium contains at least a resin and may further contain a solvent depending on the application. In other words, the coloring composition may be referred to as a pigment dispersion. The pigment dispersion can also be suitably used as an intermediate for paints, inks, etc. The pigment dispersion used as the intermediate may contain a pigment, a resin, and a solvent. The resin contained in the pigment dispersion may contain a resin-type pigment dispersant.

[0050] The pigment dispersion of this embodiment is superior to conventional pigment dispersions containing quinacridone pigments in that it has excellent dispersibility and low initial viscosity. The pigment dispersion of this embodiment is also superior in terms of viscosity stability.

[0051] When the pigment dispersion contains a solvent, the solvent can be selected from water, a water-soluble solvent, and a water-insoluble solvent. When the solvent contains at least water, an aqueous pigment dispersion is obtained. The water-soluble solvent and the water-insoluble solvent are not particularly limited. For example, they may be the same as the water-soluble solvent and the water-insoluble solvent that constitute the paint described below.

[0052] Examples of dispersers used to prepare the aqueous pigment dispersion include horizontal sand mills, vertical sand mills, annular bead mills, attritors, microfluidizers, high-speed mixers, homomixers, homogenizers, high-pressure homogenizers, ball mills, paint shakers, roll mills, stone mills, ultrasonic dispersers, high-pressure dispersers, opposed collision dispersers, and oblique collision dispersers.

[0053] Furthermore, prior to dispersion, pre-dispersion using a milling mixer such as a kneader or a three-roll mill, or solid dispersion using a two-roll mill, etc. may be performed. After dispersion using various dispersers, post-treatments such as storing the mixture in a heated state at 30 to 80°C for several hours to about a week, and post-treatments using an ultrasonic disperser or a collision-type beadless disperser improve the dispersion stability of the pigment dispersion.

[0054] <Paint> In one embodiment, the naphthol-based azo pigment can be used as a paint. The paint can contain the naphthol-based azo pigment, a resin, and a solvent. The paint preferably uses the pigment dispersion already described above, and may further contain other resins (binder resins, etc.).

[0055] The other resins include thermosetting resins and thermoplastic resins. The thermosetting resins preferably have a glass transition temperature of 10°C or higher. The thermosetting resins include self-curing resins and resins that are cured by the combined use of a curing agent. Examples of thermosetting resins include acrylic resins, polyester resins, polyurethane resins, and melamine resins. Furthermore, the thermosetting resin preferably has a functional group capable of reacting with a curing agent. Examples of the functional group include a carboxyl group and a hydroxyl group. Examples of the curing agent include an isocyanate curing agent, an epoxy curing agent, an aziridine curing agent, and an amine curing agent. The thermoplastic resin is preferably a resin having a glass transition temperature of 30° C. or higher. Examples of the thermoplastic resin include nitrocellulose resin, acrylic resin, polyester resin, etc. A thermosetting resin and a thermoplastic resin may be used in combination.

[0056] The solvent may be water, a water-insoluble solvent, or a water-soluble solvent. When the solvent contains at least water, it can constitute a water-based paint. Examples of the non-water-soluble solvent include toluene, xylene, butyl acetate, methyl acetate, methyl isobutyl ketone, and aliphatic hydrocarbons. The water-soluble solvent may be, for example, a monohydric alcohol, a dihydric alcohol, etc. Examples of the water-soluble solvent include monohydric alcohols such as ethanol, n-propanol, isopropanol, and isobutanol; dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol; and trihydric or higher polyhydric alcohols such as glycerin. The water-soluble solvent may be a water-dilutable monoether derived from a polyhydric alcohol, such as methoxypropanol or methoxybutanol. Other examples include water-dilutable glycol ethers such as butyl glycol and butyl diglycol.

[0057] In one embodiment, the paint can further contain a lustrous material. Examples of the lustrous material include metal flakes, mica, and coated glass flakes. Examples of metal flakes include aluminum flakes and gold powder. Examples of mica include regular mica and coated mica. Examples of coated glass flakes include glass flakes coated with a metal oxide such as titanium oxide. The content of the lustrous material is preferably 0.1 to 10 mass% relative to 100 mass% of the paint. The lustrous material is preferably particles having an average thickness of 0.5 to 10 μm and an average particle size of 5 to 50 μm.

[0058] The paint may further contain other components, such as color pigments and additives. The method for producing the paint and the methods for applying and drying the paint are not particularly limited, and methods well known in the art can be applied. Examples of uses of the paint include paint for metals and paint for plastics.

[0059] In one embodiment, the paint can be suitably applied to substrates such as metals, resins, wood, concrete, and stone. Examples of metals include iron, aluminum, stainless steel, silver, copper, and gold, as well as alloys containing these. Examples of the shape of the substrate include flat or curved plates, rods, cylinders, and spheres. Examples of resin substrates include molded bodies formed by known methods. Examples of types of resin include polyolefin resins, polyacrylic resins, polycarbonate resins, polystyrene resins, acrylonitrile-styrene copolymer resins, polyvinyl chloride resins, acetate resins, ABS resins, polyester resins, and polyamide resins.

[0060] <Ink> In one embodiment, the naphthol-based azo pigment can be suitably used in ink applications. The ink contains the pigment of the above embodiment and a dispersion medium, and the dispersion medium can be selected appropriately depending on the type of printing ink. Inks can be broadly classified into solvent-based printing inks, water-based printing inks, and actinic energy ray-curable printing inks depending on the presence or absence of a solvent and the type of dispersion medium. Inks can also be classified depending on the printing format, for example, into offset printing inks, flexographic printing inks, gravure printing inks, color filter inks, inkjet printing inks, etc. The pigment of this embodiment has excellent dispersibility, coloring power, clarity, and transparency, and can therefore be suitably used in a variety of printing ink applications. Representative printing inks are exemplified below.

[0061] <Inkjet printing ink> In one embodiment, the naphthol-based azo pigment can be used in inkjet printing inks (hereinafter referred to as IJ inks). In one embodiment, the IJ ink contains a pigment and a resin. In another embodiment, the IJ ink preferably contains a pigment, a resin, and a solvent. The IJ ink is preferably prepared using a pigment dispersion containing a pigment, a resin, and, if necessary, a solvent. In another embodiment, the IJ ink may be a composition in which the resin in the IJ ink of the previously described embodiment is replaced with a polymerizable compound, or a composition in which a resin and a polymerizable compound are used in combination. For example, an IJ ink can be prepared by mixing a pigment dispersion with an IJ ink resin, where the resin in the pigment dispersion and the resin used to prepare the IJ ink can be the same or different.

[0062] Inkjet inks can be broadly classified into (solvent-based) inkjet inks, water-based inkjet inks, and actinic radiation-curable inkjet inks, depending on the presence or absence of a solvent and the type of solvent, as well as the type of resin or polymerizable compound used as the dispersion medium. Actinic radiation-curable inkjet inks can be further classified into photocurable inkjet inks and electron beam-curable inkjet inks, depending on the curing method used to cure the polymerizable compound. Although not particularly limited, the coloring composition of the above embodiment can be suitably used as an aqueous inkjet ink. Below, an aqueous inkjet ink will be described as an example of an inkjet ink.

[0063] When the total mass of the water-based IJ ink is taken as 100 mass %, the content of the pigment is preferably from 0.5 to 30 mass %, and more preferably from 1 to 15 mass %.

[0064] The resin used in water-based inkjet ink is important for ensuring the ink adheres well to the substrate. Examples of resins include acrylic resins, olefin-maleic acid resins, styrene-acrylic resins, polyester resins, polyamide resins, and polyurethane resins. The resin may be in the form of, for example, a water-soluble resin or emulsion particles. Of these, emulsion particles are preferred. The emulsion particles may be, for example, particles of a single composition or core-shell particles, and can be selected and used as desired. When emulsion particles are used, it is easy to reduce the viscosity of the aqueous inkjet ink, and printed matter with excellent water resistance can be easily obtained.

[0065] The resin content of the aqueous IJ ink is preferably 2 to 30% by mass, and more preferably 3 to 20% by mass, relative to 100% by mass of the nonvolatile content. When the IJ ink contains a resin within the above range, the ejection stability and fixability tend to be improved.

[0066] From the viewpoint of forming a water-based inkjet ink, the solvent contains at least water. The solvent may further contain either a water-insoluble solvent or a water-soluble solvent. In one embodiment, the solvent preferably contains both water and a water-soluble solvent. Examples of the water-soluble solvent include glycol ethers, diols, etc. These solvents penetrate into the substrate very quickly, even into substrates with low liquid absorption.

[0067] Examples of low-absorbency substrates include coated paper, art paper, vinyl chloride, plastic film, and leather. When a solvent with excellent permeability to the substrate is used as described above, drying during printing is fast, and accurate printing can be easily achieved. Furthermore, when a water-soluble solvent with a high boiling point is used, the solvent also acts as a wetting agent.

[0068] The water-soluble solvent is important for preventing the water-based inkjet ink from drying and solidifying in the nozzle of the printer head, and for ensuring ink ejection stability. Examples of water-soluble solvents include ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, polyethylene glycol, glycerin, tetraethylene glycol, dipropylene glycol, ketone alcohols, diethylene glycol monobutyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, 1,2-hexanediol, N-methyl-2-pyrrolidone, substituted pyrrolidone, 2,4,6-hexanetriol, tetrafurfuryl alcohol, and 4-methoxy-4-methylpentanone.

[0069] In one embodiment, the total content of water and the water-soluble solvent is preferably 30 to 70% by mass relative to 100% by mass of the IJ ink. Here, the content of the water-soluble solvent may be preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and even more preferably 30 to 70% by mass, relative to the total mass of water and the water-soluble solvent.

[0070] IJ inks can further contain additives such as drying accelerators, penetrants, preservatives, chelating agents, pH adjusters, antifoaming agents, wetting agents, and surfactants.

[0071] In this specification, the actinic energy ray-curable IJ ink contains, in addition to the naphthol-based azo pigment, a polymerizable compound, a photopolymerization initiator, etc. The content of the pigment is preferably 0.5 to 30 mass%, and more preferably 1 to 15 mass%, of the total mass of the actinic energy ray-curable IJ ink taken as 100 mass%.

[0072] The polymerizable compound used in actinic radiation-curable inkjet inks is important for achieving ink fixation to the printed material (substrate). There are no particular limitations on the polymerizable compound, so long as it undergoes a polymerization reaction and hardens when some kind of energy is applied. Monomers, oligomers, and polymers can be used regardless of their type, but radically polymerizable monomers are preferred. Polymerizable monomers can be used alone or in combination to adjust the reaction rate, physical properties of the cured film, physical properties of the ink, and the like. Furthermore, the polymerizable monomer may be a monofunctional monomer or a polyfunctional monomer with two or more functionalities, with a combination of monofunctional and polyfunctional monomers being preferred. Examples of the polymerizable compound include (meth)acrylate compounds, vinyl ether compounds, compounds having a (meth)acrylate group and a vinyl ether group, allyl compounds, N-vinyl compounds, unsaturated carboxylic acids, etc. Among these, one or more compounds selected from (meth)acrylate compounds, compounds having a (meth)acrylate group and a vinyl ether group, and N-vinyl compounds are preferred.

[0073] In one embodiment, the content of the polymerizable compound is preferably 30 to 99 mass %, more preferably 50 to 95 mass %, and even more preferably 60 to 90 mass %, based on the total mass of the active energy ray-curable IJ ink.

[0074] The active energy ray-curable inkjet ink can contain a photopolymerization initiator. In one embodiment, the photopolymerization initiator can be a molecular cleavage-type or hydrogen abstraction-type photopolymerization initiator that generates radicals. In one embodiment, the photopolymerization initiators can be used alone or in combination of two or more. Alternatively, a photopolymerization initiator that generates radicals and a photopolymerization initiator that generates cations can be used in combination. Examples of the photopolymerization initiator include alkylphenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, oxime ester-based photopolymerization initiators, benzophenone-based photopolymerization initiators, etc. Among these, from the viewpoint of curability and storage stability, at least one selected from the group consisting of bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one is preferred.

[0075] The content of the photopolymerization initiator is preferably 2 to 30% by mass, more preferably 5 to 20% by mass, and even more preferably 10 to 20% by mass, based on the total mass of the polymerizable compound. When the content of the photopolymerization initiator is 2% by mass or more, good curability can be easily obtained. On the other hand, when the content is 20% by mass or less, the curing speed can be efficiently increased, no undissolved components of the photopolymerization initiator are generated even at low temperatures, and good inkjet ejection properties can be easily obtained.

[0076] The active energy ray-curable IJ ink may contain additives such as a polymerization inhibitor, an organic solvent, a surface conditioner, and a pigment dispersant, as needed.

[0077] In one embodiment, the inkjet ink is particularly suitable for use as a red or orange ink. The inkjet ink may be combined with inks of colors other than red or orange to form an ink set. Examples of colors that can be combined with the inkjet ink include cyan, yellow, black, white, magenta, green, blue, violet, pink, gold, silver, and bronze.

[0078] The ink set may be, for example, a five-color ink set that adds cyan, yellow, magenta, and black to the red or orange inks using the inkjet inks of the above-described embodiment. In other embodiments, it may be suitable for use as an ink set of six or more colors by adding special colors such as green and violet. The pigment concentration, viscosity, dynamic viscoelasticity, surface tension, application order, evaporation rate of volatile components, and other factors of each ink are design factors and can be adjusted appropriately depending on the desired properties.

[0079] The inkjet ink of the above embodiment can be applied to a variety of conventionally known substrates, including highly water-absorbent substrates such as plain paper, fabric, and knitted fabric, low-absorbent substrates such as art paper, coated paper, vinyl chloride, wood, concrete, polyethylene film, polypropylene film, polyethylene terephthalate film, natural leather, and artificial leather, and non-water-absorbent substrates such as metals (aluminum, stainless steel, etc.).

[0080] <Colored resin composition> In one embodiment, the naphthol-based azo pigment can be suitably used in a colored resin composition. The colored resin composition can be used to produce a resin molded product. The colored resin composition contains the naphthol-based azo pigment of the above embodiment and a dispersion medium (resin). The colored resin composition may further contain components known to those skilled in the art, such as a lubricant and a reinforcing material.

[0081] Examples of the resin include polyethylene resin, polypropylene resin, polystyrene resin, acrylonitrile-styrene (AS) resin, acrylonitrile-butadiene-styrene (ABS) resin, and polyvinyl chloride (PVC) resin.

[0082] In one embodiment, the resin of the colored resin composition is preferably a polyethylene resin, a polystyrene resin, an ABS resin, or a polyvinyl chloride resin, and more preferably a polyvinyl chloride resin. The naphthol-based azo pigment of this embodiment is particularly suitable for polyvinyl chloride resins among the above resins. Therefore, in one embodiment, the colored resin composition preferably contains a naphthol-based azo pigment and a resin containing a polyvinyl chloride resin. In such a colored resin composition, the naphthol-based azo pigment of the above embodiment is uniformly and finely dispersed in the resin containing a polyvinyl chloride resin. Therefore, the naphthol-based azo pigment composition of the above embodiment can provide a high-quality colored resin composition. The colored resin composition of the present invention can be molded into a sheet or film and used for interior materials, cover members, etc. [Example]

[0083] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples. Note that "parts" means "parts by mass" and "%" means "% by mass."

[0084] The abbreviations and product names used in the following examples are as follows: <Coupler> Naphthol AS-RL: 3-hydroxy-4'-methoxy-2-naphthanilide (Sigma-Aldrich) Naphthol AS-E: 4'-chloro-3-hydroxy-2-naphthanilide (Sigma-Aldrich) Naphthol AS-m-OMe: 3-hydroxy-3'-methoxy-2-naphthanilide (Synsonics) Naphthol AS-p-COOH: 4-[[(3-hydroxy-2-naphthyl)carbonyl]amino]benzoic acid Naphthol AS-p-CONH2: N-(4-carbamoylphenyl)-3-hydroxy-2-naphthamide Naphthol AS-OL: 3-hydroxy-2'-methoxy-2-naphthanilide (Sigma-Aldrich)

[0085] <Bass> M-60: 3-amino-4-methylbenzamide (Tokyo Chemical Industry Co., Ltd.) M-70: 4-aminobenzamide (Tokyo Chemical Industry Co., Ltd.) 4-Aminobenzoic acid (Tokyo Chemical Industry Co., Ltd.) 4-Chloroaniline (Tokyo Chemical Industry Co., Ltd.) 4-Methoxyaniline (Tokyo Chemical Industry Co., Ltd.)

[0086] <Naphthol-based azo pigments> [ka] JPEG2025151836000006.jpg48149JPEG2025151836000007.jpg48138 JPEG2025151836000008.jpg49145JPEG2025151836000009.jpg3698

[0087] [Preparation of Coupler] (Production Example 1) Production of Naphthol AS-p-COOH In a 4 L four-neck flask equipped with an internal thermometer, a gas removal tube, and a stirrer, 494.0 parts of 3-hydroxy-2-naphthoic acid and 2470 parts of xylene were placed, and 6 parts of N,N'-dimethylformamide was added. 328 parts of thionyl chloride was added thereto over 1 hour at 47-50°C, and the mixture was then stirred for 3 hours until gas evolution ceased, yielding a xylene solution of 3-hydroxy-2-naphthoyl chloride. Separately, 1800 parts of N-methylpyrrolidone were introduced into a 10-L four-neck flask equipped with a dropping funnel, reflux condenser, internal thermometer, and stirrer, and 291.5 parts of sodium carbonate were added. Then, 342.9 parts of 4-aminobenzoic acid were added at 25°C. The resulting xylene solution of 3-hydroxy-2-naphthoyl chloride was added over 6.5 hours while stirring at 25-28°C. After stirring for another 30 minutes, the product was suction filtered and the filter cake was washed with 215 parts of xylene (10 times). Furthermore, 2500 parts of water were introduced into a 6-L four-neck flask equipped with a distillation bridge equipped with a stirrer, internal thermometer, and a 1-L single-neck flask as a receiver, followed by the filter cake. Next, 200 parts of sodium carbonate were added, and the mixture was heated to 100°C to distill off the xylene and water. The product was filtered under suction at 100°C, and the filter cake was washed with a total of 2100 parts of water in three portions until neutral, and the filter cake was dried at 80°C for 24 hours to give 662 parts of naphthol AS-p-COOH.

[0088] (Production Example 2) Production of naphthol AS-p-CONH2 Naphthol AS-p-CONH2 was obtained in the same manner as in Production Example 1, except that 342.9 parts of 4-aminobenzoic acid in Production Example 1 was replaced with 340.4 parts of 4-aminobenzamide.

[0089] <1> Pigment manufacturing Example 1: Production of Pigment 1 A suspension was prepared by adding 18.02 parts of M-60 as a base component to 267 parts of water and stirring. 55.6 parts of 30% hydrochloric acid was added thereto and stirred for 15 minutes. 57.2 parts of ice was then added and stirred until the temperature reached -5°C to 5°C, and 21.4 parts of a 40% aqueous sodium nitrite solution was added over 20 minutes. Diazotization was carried out by stirring at 5°C or below for 90 minutes. Sulfamic acid was added to the reaction mixture obtained by the diazotization to eliminate excess nitrous acid. Sulfamic acid was added until no free nitrous acid was detected using potassium iodide paper. 24.9 parts of sodium acetate and 2.75 parts of 80% acetic acid were added to the mixture to obtain a solution containing a diazonium salt. Separately, a mixture of 190 parts of methanol as a water-soluble organic solvent and 30.9 parts of 30.5% aqueous sodium hydroxide solution was adjusted to 15 to 25°C. 35.92 parts of naphthol AS-RL as a coupler component was added and dissolved therein to prepare a coupler solution. This solution was added to the solution containing the diazonium salt over 20 minutes to carry out a coupling reaction. The slurry obtained by the coupling reaction was stirred at 25°C for 30 minutes. The slurry was then heated to 70°C and stirred for 60 minutes. The slurry was filtered and washed with water at 60°C to obtain a press cake of a naphthol-based azo pigment. The press cake was dried at 80°C for 24 hours and then pulverized to obtain 53.9 parts of Pigment 1 represented by chemical formula (5).

[0090] (Examples 2 to 8) Production of Pigments 2 to 8 Pigments 2 to 8 were obtained in the same manner as in Example 1, except that the base component was changed to M-60 using the corresponding base type and base mass part in Table 1, and the coupler component was changed to Naphthol AS-RL using the corresponding coupler type and coupler mass part in Table 1.

[0091] Example 9: Preparation of Pigment 9 Pigment 9 was obtained in the same manner as in Example 1, except that M-60 was used as the base component in the corresponding base type and base mass parts in Table 1, naphthol AS-RL was used as the coupler component in the corresponding coupler type and coupler mass parts in Table 1, and the solvent used to dissolve the coupler solution was changed from 190 parts methanol to 190 parts acetonitrile.

[0092] Example 10: Preparation of Pigment 10 Pigment 10 was obtained in the same manner as in Example 1, except that M-60 was used as the base component in accordance with the base type and base mass parts in Table 1, naphthol AS-RL was used as the coupler component in accordance with the coupler type and coupler mass parts in Table 1, and the solvent used to dissolve the coupler solution was changed from 190 parts of methanol to a mixed solvent of 90 parts of isopropanol and 100 parts of water.

[0093] Example 11: Preparation of Pigment 11 Pigment 11 was obtained in the same manner as in Example 1, except that the amount of water used to suspend the base component was reduced by 40 parts, and 40 parts of methanol was added after the addition of sodium acetate following diazotization.

[0094] Example 12: Preparation of Pigment 12 Naphthol-based azo pigment 12 was obtained in the same manner as in Example 2, except that the amount of water used to suspend the base component was reduced by 20 parts and 20 parts of methyl ethyl ketone was added instead, and the solvent used for the coupler solution was changed from 190 parts of methanol to a mixed solvent of 20 parts of methyl ethyl ketone and 170 parts of water.

[0095] Example 13: Preparation of Pigment 13 Pigment 13 was obtained in the same manner as in Example 1, except that the water used to suspend the base component was reduced by 70 parts, 40 parts of acetone was added after the addition of sodium acetate after diazotization, the solvent used to dissolve the coupler was changed from 190 parts of methanol to 190 parts of acetone, and the heating temperature of the slurry after coupling was changed from 70°C to 45°C.

[0096] (Example 14) Preparation of Pigment 14 A press cake prepared in the same manner as in Example 2 was reslurried in a mixed solution of 100 parts water and 100 parts methyl ethyl ketone, and stirred for 1 hour at 35° C. The slurry was filtered, washed with water at 60° C., dried at 80° C. for 24 hours, and then pulverized to obtain pigment 14 represented by chemical formula (6).

[0097] (Comparative Examples 1 and 2) Production of Pigments 101 and 102 Pigments 101 to 102 were obtained in the same manner as in Example 1, except that M-60 was used as the base component in the corresponding base type and base mass parts in Table 1, naphthol AS-RL was used as the coupler component in the corresponding coupler type and coupler mass parts in Table 1, and the solvent used in the coupler solution was changed from 190 parts methanol to 280 parts water.

[0098] (Comparative Example 3) Preparation of Pigment 103 A press cake prepared in the same manner as in Comparative Example 2 was reslurried in a mixed solution of 100 parts water and 100 parts methyl ethyl ketone and stirred for 1 hour at 35° C. The slurry was filtered, washed with water at 60° C., dried at 80° C. for 24 hours, and then pulverized to obtain pigment 103 represented by chemical formula (6).

[0099] (Comparative Example 4) Pigment 104 Pigment 104 represented by chemical formula (15) was obtained in the same manner as in Example 1, except that the base component was changed from M-60 to the corresponding base type and base mass parts in Table 1, and the coupler component was changed from Naphthol AS-RL to the corresponding coupler type and coupler mass parts in Table 1.

[0100] (Comparative Example 5) Pigment 105 CI Pigment Red 150 (TOSHIKI RED 150T, Tokyo Color Materials Co., Ltd., average primary particle diameter 140 nm, average aspect ratio 2.3), which is a naphthol-based azo pigment of chemical formula (16), was used as pigment 105.

[0101] (Comparative Example 6) Pigment 106 CI Pigment Red 122 (TONER MAGENT E, Heubach, average primary particle diameter 80 nm, average aspect ratio 3.25), a quinacridone pigment of chemical formula (17), was used as pigment 106.

[0102] <2> Measurement of particle size and major / minor diameter ratio The average primary particle size and aspect ratio of the colored compositions of the Examples and Comparative Examples were determined by observation with a transmission electron microscope (TEM) as follows. For 50 primary particles of the coloring composition randomly selected from multiple photographs taken at a magnification of 10,000 times using a transmission electron microscope, a rectangle with the smallest area circumscribing the particle image was drawn, and the length of the long side of the rectangle was taken as the major axis, and the length of the short side of the rectangle was taken as the minor axis. The average value of the major axes was taken as the average primary particle diameter, and the average value of the ratio of the major axis to the minor axis was taken as the aspect ratio.

[0103] In Examples 1 to 14 and Comparative Examples 1 to 4, the structure of the produced pigments, the raw materials used in the production of the pigments, the average primary particle diameter, and the aspect ratio are shown in Table 1. [Table 1]

[0104] <3> coloring composition The following relates to specific examples of coloring compositions containing the naphthol azo pigments prepared above. pigment dispersion (A1) Preparation of pigment dispersion (Example A-1) Preparation of pigment dispersion a-1 The following raw materials and 70 parts of zirconia beads with a diameter of 1.25 mm were placed in a 70 ml glass bottle and dispersed for 60 minutes using a paint shaker manufactured by Red Devil Co., Ltd., to obtain a dispersion with a non-volatile content of 19.3%. Naphthol azo pigment 1:3.15 parts Pigment dispersant (Allnex polyester-modified acrylic acid polymer, ADDITOL XW6528): 5.25 parts Wetting agent (Allnex, ADDITOL VXW6374): 0.95 parts Antifoaming agent (Allnex, ADDITOL VXW6211): 0.63 parts Ion-exchanged water: 21.52 parts Next, the zirconia beads were removed from the dispersion to obtain pigment dispersion a-1.

[0105] (Examples A-2 to A-14, Comparative Examples A-1 to A-6) Preparation of Pigment Dispersions a-2 to a-14, a-101 to a-106 The same procedure as in Example A-1 was carried out except that Pigment 1 in Example A-1 was changed as shown in Table 2, to obtain Pigment Dispersions a-2 to a-14 and a-101 to a-106.

[0106] (A2) Evaluation of pigment dispersion <Initial viscosity and viscosity stability> The initial viscosity of the resulting pigment dispersion was measured at 25°C using an E-type viscometer ("ELD-type viscometer" manufactured by Toki Sangyo Co., Ltd.). In the same manner, the viscosity was measured after aging at 60°C for one week. The viscosity increase rate relative to the initial viscosity was calculated based on the obtained measurements, and used as an index of viscosity stability, which was evaluated according to the following evaluation criteria. The results are shown in Table 2. The lower the initial viscosity, the better the dispersibility. Furthermore, the smaller the viscosity increase rate, the better the dispersion stability. A rating of "4" or "3" on the following evaluation criteria is considered to be at a practical level.

[0107] (Evaluation criteria for initial viscosity) 4: Initial viscosity is less than 5.0 mPa·s. Excellent 3: The initial viscosity is 5.0 mPa·s or more and less than 7.5 mPa·s. Good 2: The initial viscosity is 7.5 mPa·s or more and less than 10.0 mPa·s. 1: The initial viscosity is 10.0 mPa·s or more. Very poor

[0108] (Evaluation criteria for viscosity stability) 4: Viscosity increase rate is less than 20%. Very good 3: Viscosity increase rate is 20% or more and less than 30%. Good 2: Viscosity increase rate is 30% or more but less than 40%. 1: Viscosity increase rate is 40% or more. Very poor

[0109] [Table 2]

[0110] water-based paint (B1) Preparation of water-based paints and coating films (Example B-1) Preparation of water-based paint b-1 and production of paint film The following raw materials were mixed using a mixer to obtain a water-based paint b-1 with a non-volatile content of 49.5%. Pigment dispersion a-1: 1.4 parts Acrylic resin (DIC Corporation, Burnock WD-304): 13.6 parts Melamine resin (Allnex, Cymel 325): 3.4 parts

[0111] The resulting water-based paint b-1 was applied to a 100 μm-thick commercially available polyethylene terephthalate (PET) film using a 7 mil applicator. After application, the PET film was dried at room temperature for 18 hours. It was then dried at 60°C for 5 minutes and at 140°C for 20 minutes to obtain a coated film.

[0112] (Examples B-2 to B-14, Comparative Examples B-1 to B-6) Preparation of Water-Based Coatings b-2 to b-14, b-101 to b-106 and Fabrication of Coating Films) Except for changing the pigment dispersion 1 of Example B-1 as shown in Table 3, the same procedure as in Example B-1 was carried out to obtain water-based paints b-2 to b-14 and b-101 to b-106 and their coating films.

[0113] (B2) Evaluation of paint film <Coloring power> The coated films (coated objects) were visually observed and evaluated according to the following criteria. The results are shown in Table 3. A rating of "3" or "2" on the following criteria is considered to be at a practical level. (Evaluation criteria for coloring strength) 3: Extremely strong coloring power compared to standard paint 2: Higher coloring strength than standard paint 1: Tinting strength is equal to or inferior to the standard paint

[0114] <Weather resistance> The coated film was subjected to an accelerated weathering test using an ultra-accelerated weathering tester (Iwasaki Electric Co., Ltd., Eye Super Xenon Tester SUV-W151) at 90 mW / cm 2 The test was carried out for 96 hours (four 12-hour day and night cycles), and the color difference (ΔE*) before and after the weather resistance test was evaluated using a Konica Minolta CM-700d color difference meter. The results are shown in Table 3. A rating of "3" or "2" on the following scale is considered to be at a practical level. (Weather resistance evaluation criteria) 3: Color change before and after the test (ΔE*) is less than 2.5, good 2: The color change (ΔE*) before and after the test is 2.5 or more and less than 4, suitable for practical use 1: Color change before and after the test (ΔE*) is 4 or more, defective

[0115] [Table 3]

[0116] <c>solvent paint (C1) Preparation of solvent paint (Example C-1) Preparation of solvent paint c-1 Naphthol azo pigment 1:9 parts, Acrylic resin (DIC Corporation, Acrydic 47-712): 7.7 parts Dispersion medium (a mixed solvent of toluene, xylene, butyl acetate, and T-SOL150FLUID manufactured by ENEOS Corporation in a mass ratio of 3:3:2:2): 40.7 parts The above materials and 230 parts of steel beads were placed in a sealable glass container, sealed, and dispersed for 60 minutes using a Red Devil paint shaker. 75.4 parts of Acrydic 47-712 and 17.2 parts of melamine resin (DIC Corporation, Amidia L-117-60) were then added and dispersed for another 10 minutes. The steel beads were then removed to obtain solvent paint c-1.

[0117] (Examples C-2 to C-14, Comparative Examples C-1 to C-6) Preparation of solvent paints c-2 to c-14, c-101 to c-106 The same procedure as in Example C-1 was carried out except that the naphthol-based azo pigment 1 in Example C-1 was changed as shown in Table 4, to obtain solvent paints c-2 to c-14 and c-101 to c-106.

[0118] (C2) Evaluation of solvent-based paints <Initial viscosity and viscosity over time> The resulting solvent paint was placed in a sealable glass bottle, sealed, and immersed in a thermostatic bath at 25°C for 1 hour to maintain a constant temperature. The viscosity (referred to as "initial viscosity") was measured at 25°C and 6 rpm using a B-type viscometer (a BII-type viscometer manufactured by Toki Sangyo Co., Ltd.). The viscosity was also measured again in the same manner after storage at 40°C for 1 week (referred to as "viscosity over time"). The results are shown in Table 4. A rating of "4" or "3" on the following evaluation criteria indicates a practical level.

[0119] (Evaluation criteria for initial viscosity and viscosity over time) 4: Viscosity is less than 4000 mPa·s, very good. 3: Viscosity is 4000 mPa·s or more and less than 10000 mPa·s, good. 2: Viscosity is 10,000 mPa·s or more and less than 13,000 mPa·s, defective. 1: Viscosity is 13,000 mPa·s or more, or gelation has occurred, extremely poor.

[0120] (C3) Preparation of top coat clear paint Acrylic resin (DIC Corporation, Acrydic 44-179): 120 parts Melamine resin (DIC Corporation, Amidia L117-60): 30 parts Dilution solvent (a mixed solvent of toluene, xylene, T-SOL150FLUID manufactured by ENEOS Corporation, ethyl 3-ethoxypropionate, and ethyl acetate in a mass ratio of 3:2:2:1:2): 50 parts The above materials were mixed and stirred in a high-speed mixer to obtain a top coat clear paint.

[0121] (C4) Preparation of painted boards Preparation of painted plate c'-1 One part of the solvent-based paint c-1 prepared in Example C-1 was sprayed onto a primer-treated steel plate using a spray gun. To adjust the viscosity to facilitate spraying, a dilution solvent (a mixed solvent consisting of toluene, xylene, T-SOL150FLUID manufactured by ENEOS Corporation, ethyl 3-ethoxypropionate, and ethyl acetate in a mass ratio of 3:2:2:1:2) was appropriately mixed with the solvent-based paint to a concentration of approximately 10 to 20% by mass. The painting was done in nine separate coats, followed by six separate coats of top coat clear paint. After drying at 25°C for 1 hour, the coated plate was dried at 140°C for 30 minutes to obtain a coated product, coated plate c'-1.

[0122] Preparation of painted plates c'-2 to c'-14, c'-101 to c'-106 Coated plates c'-2 to c'-14 and c'-101 to c'-106 were obtained in the same manner as for the preparation of coated plate c'-1, except that the solvent paint c-1 was changed as shown in Table 4.

[0123] (C5) Evaluation of painted panels <Coloring power> The coated panels were visually inspected and evaluated according to the following criteria. The results are shown in Table 4. A rating of "3" or "2" on the following criteria is considered to be at a practical level. (Evaluation criteria for coloring strength) 3: Extremely strong coloring power compared to standard painted boards 2: Higher coloring strength than standard painted board 1: Tinting strength is equal to or inferior to the standard painted board

[0124] <Weather resistance> For the weather resistance test, the above painted panels were subjected to an accelerated weather resistance test using an ultra-accelerated weather resistance tester (Iwasaki Electric Co., Ltd., Eye Super Xenon Tester SUV-W151) at 90 mW / cm 2 The test was carried out for 96 hours (four 12-hour day and night cycles), and the color difference (ΔE*) before and after the weather resistance test was evaluated using a Konica Minolta CM-700d color difference meter. The results are shown in Table 4. A rating of "3" or "2" on the following scale is considered to be at a practical level. (Weather resistance evaluation criteria) 3: Color change before and after the test (ΔE*) is less than 2.5, good 2: The color change (ΔE*) before and after the test is 2.5 or more and less than 4, suitable for practical use 1: Color change before and after the test (ΔE*) is 4 or more, defective

[0125] [Table 4]

[0126] <d>Water-based inkjet ink (D1) Preparation of water-based inkjet ink (water-based IJ ink) (Example D-1) Preparation of Water-Based IJ Ink d-1 200 parts of zirconia beads with a diameter of 1.25 mm and the following raw materials were placed in a 200 ml glass bottle and dispersed for 6 hours using a Red Devil paint shaker. Naphthol azo pigment 1: 19.0 parts Styrene-acrylic acid copolymer (BASF Japan, JONCRYL 61J): 16.4 parts Surfactant (Kao Corporation, Emulgen 420): 5.0 parts Ion-exchanged water: 59.6 parts Next, the zirconia beads were removed from the dispersion to obtain a pigment dispersion.

[0127] Next, the pigment dispersion and the following raw materials were mixed and stirred for 30 minutes using a high-speed mixer to obtain a mixture. Obtained pigment dispersion: 12.5 parts Styrene-acrylic acid copolymer (BASF Japan, JONCRYL 60): 3.3 parts Surfactant (Kao Corporation, Emulgen 420): 2.0 parts Ion-exchanged water: 64.9 parts Next, diethylene glycol monobutyl ether was added to the above mixture to adjust the viscosity at 25°C to 2.5 mPa·s (25°C) and the surface tension to 40 mN / m. The mixture was then filtered using a 1.0 μm membrane filter and then further filtered using a 0.45 μm membrane filter to obtain water-based IJ ink d-1.

[0128] (Examples D-2 to D-14, Comparative Examples D-1 to D-6) Preparation of Water-Based IJ Inks d-2 to d-14 and d-101 to d-106 Except for changing the naphthol azo pigment 1 in Example D-1 as shown in Table 5, the same procedure as in Example D-1 was carried out to obtain water-based IJ inks d-2 to d-14 and d-101 to d-106.

[0129] (D2) Evaluation of water-based inkjet ink <Viscosity stability> The initial viscosity of each water-based inkjet ink was measured at 25°C using an E-type viscometer ("ELD-type viscometer" manufactured by Toki Sangyo Co., Ltd.). In the same manner, the viscosity was measured after aging at 70°C for two weeks. Using each measured value, the viscosity increase rate relative to the initial viscosity was calculated, which was used as an index of viscosity stability and evaluated according to the following criteria. The results are shown in Table 5. The smaller the viscosity increase rate, the better the viscosity stability, and a rating of "3" on the following evaluation criteria is considered to be at a practical level. (Evaluation criteria for viscosity stability) 3: Viscosity increase rate is less than 15% 2: Viscosity increase rate is 15% or more but less than 30% 1: Viscosity increase rate is 30% or more

[0130] <Coloring power> The prepared aqueous inkjet ink was filled into the cartridge of a Seiko Epson PX-105 printer (piezo inkjet printer), and a solid print was made on A4-sized plain paper. The print was visually observed and evaluated according to the following criteria. The results are shown in Table 5. A rating of "3" or "2" on the following criteria is considered to be at a practical level. (Evaluation criteria for coloring strength) 3: Coloring strength is significantly higher than the standard print 2: Higher coloring strength than the standard print 1: Coloring strength is equal to or inferior to the reference print

[0131] <Light resistance> Using the inkjet ink-coated products prepared as described above and standard blue-dyed fabrics (blue scale) of grades 2 to 8 specified in JIS L 0841:2004, lightfastness tests were conducted using a Suga Test Instruments Xenon Weather Meter SX75 under conditions of irradiance of 60 W, black panel temperature of 63°C, and 50% RH, based on the third exposure method of the "Test Method for Color Fastness to Xenon Arc Lamp Light" specified in JIS L 0843:2006. The degree of fading of the blue scale for each grade was then visually assessed to determine the lightfastness of the inkjet ink-coated products. The results are shown in Table 5. A rating of "3" or "2" on the following scale indicates a practical level. (Evaluation criteria for light resistance) 3: Blue scale level 7 or above 2: Blue scale level 5 or above and level 6 or below 1: Blue scale level 4 or below

[0132] In addition, when the substrate was changed from A4 size plain paper to coated paper, polypropylene film (OPP film), aluminum foil, and artificial leather (polyurethane sheet), the same results were obtained when the coloring power was evaluated. When the substrate was not paper, the substrate was attached to A4 size plain paper. In addition, when a tank filled with the prepared water-based inkjet ink was installed as magenta ink in a Canon MAXIFYMB5430 (thermal inkjet printer), the coloring power was evaluated, and similar results were obtained.

[0133] [Table 5]

[0134] <e>Active energy ray curable inkjet ink (active energy ray curable IJ ink) (E1) Preparation of active energy ray curable inkjet ink (Example E-1) Preparation of active energy ray-curable IJ ink e-1 The following materials were mixed and stirred in a high-speed mixer until uniform, and the resulting mill base was dispersed in a horizontal mill for 1 hour to obtain a pigment dispersion. Naphthol azo pigment 1:5 parts Pigment dispersant (Lubrizol, Solsperse 32000): 1 part Polymerizable compound (dipropylene glycol diacrylate, Miramer M222, manufactured by BASF Japan): 19 parts Next, to 25 parts of the obtained pigment dispersion, the following materials were added in order with stirring, and stirring was continued until the photopolymerization initiator was dissolved to obtain a mixture. Polymerizable compound (lauryl acrylate, manufactured by Osaka Organic Industry Co., Ltd.): 30 parts Polymerizable compound (dipropylene glycol diacrylate, Miramer M222, manufactured by BASF Japan): 5.2 parts Polymerizable compound (2-(2-vinyloxyethoxy)ethyl acrylate, VEEA-AI, manufactured by Nippon Shokubai Co., Ltd.): 30 parts Photopolymerization initiator (4-benzoyl-4'-methyl-diphenyl sulfide, KAYACURE BMS, manufactured by Nippon Kayaku Co., Ltd.): 3.0 parts Photopolymerization initiator (2,4,6-trimethylbenzoyl-diphenylphosphine oxide, Irgacure TPO, manufactured by BASF Japan): 3.0 parts Polymerization accelerator (Thought Ethyl 4-(dimethylamino)benzoate, SB-PI-704): 3.0 parts DEDG (Diethylene glycol diethyl ether, manufactured by Nippon Nyukazai Co., Ltd.): 0.5 parts Polymerization inhibitor (Seiko Chemical Co., Ltd., phenothiazine): 0.1 parts Surface conditioner (BYK Chemie polyether-modified polydimethylsiloxane, BYK-UV3510): 0.2 parts The resulting mixture was then filtered through a membrane filter with a pore size of 1 μm to remove coarse particles, yielding active energy ray-curable IJ ink e-1.

[0135] (Examples E-2 to E-14, Comparative Examples E-1 to E-6) Preparation of Water-Based IJ Inks e-2 to e-14, e-101 to e-106) Except for changing the naphthol-based azo pigment 1 in Example E-1 as shown in Table 6, the same procedure as in Example E-1 was carried out to obtain water-based IJ inks e-2 to e-14 and e-101 to e-106.

[0136] (E2) Evaluation of active energy ray curable inkjet ink <Viscosity stability> The ink was filled into a sealable storage bottle to 90% capacity and left at 60°C for two weeks. The rate of change in viscosity before and after leaving the bottle was evaluated based on the following evaluation criteria to evaluate storage stability. The evaluation results are shown in Table 6. A rating of "4" or "3" on the following criteria is considered to be at a practical level. 4: The rate of change is less than 10% of the initial value. 3: The rate of change is 10% or more but less than 15% of the initial value. 2: The rate of change is 15% or more but less than 25% of the initial value. 1: The rate of change is 25% or more compared to the initial value.

[0137] (E3) Preparation of active energy ray curable inkjet prints The prepared ink was printed under the following printing conditions: Using an inkjet ejection device (Tritec OnePassJET) equipped with a Kyocera head (resolution 600 dpi x 600 dpi), 100% solid images were printed on a Lintec PET K2411 substrate under printing conditions of an ink droplet volume of 14 pL. The film thickness of each ink was approximately 8 μm. The conveyor speed was 50 m / min, and a 160 W / cm metal halide lamp (365 nm) manufactured by Harrison Toshiba Lighting was used as the radiation source. The ink was cured in the atmosphere to obtain an inkjet print.

[0138] <Coloring power> The IJ ink prints produced above were visually observed and evaluated according to the following criteria. The results are shown in Table 6. A rating of "3" or "2" on the following criteria is considered to be at a practical level. (Evaluation criteria for coloring strength) 3: Coloring strength is significantly higher than the standard print 2: Higher coloring strength than the standard print 1: Coloring strength is equal to or inferior to the reference print

[0139] <Light resistance> Using the inkjet ink prints prepared as described above and standard blue-dyed fabrics (blue scale) grades 2 to 8 specified in JIS L 0841:2004, lightfastness tests were conducted using a Suga Test Instruments Xenon Weather Meter SX75 under conditions of 60 W irradiance, 63°C black panel temperature, and 50% RH, based on the third exposure method of the "Test Method for Color Fastness to Xenon Arc Lamp Light" specified in JIS L 0843:2006. The degree of fading of the blue scale for each grade was then visually assessed to determine the lightfastness of the inkjet ink coating. The results are shown in Table 6. A rating of "3" or "2" on the following scale indicates a practical level. (Evaluation criteria for light resistance) 3: Blue scale level 7 or above 2: Blue scale level 5 or above and level 6 or below 1: Blue scale level 4 or below

[0140] [Table 6]

[0141] <f>colored resin composition (F1) Preparation of colored resin composition and evaluation sheet (Example F-1) Preparation of Colored Resin Composition f-1 The following raw materials were stirred and mixed in a super mixer while being heated to 100°C, and then cooled to 30°C to prepare a colored resin composition f-1. Pigment: 1:4 parts naphthol azo pigment Chlorinated polyvinyl chloride resin (Kaneka Corporation, H-516A): 75.0 parts Vinyl chloride-ethylene copolymer (manufactured by Taiyo Vinyl Corporation, TE-650): 25.0 parts Impact resistance improver (Kaneka Corporation, Kane Ace FM-50): 6.0 parts Processability improver (Kaneka Corporation, Kane Ace PA-40): 5.0 parts Heat stabilizer (dimethyltin compound, AT-1500, manufactured by Nitto Kasei Co., Ltd.): 3.5 parts Lubricant (Kao Corporation stearic acid, Lunac S-70V): 0.5 parts Lubricant (Honeywell Oxidized Polyethylene Wax, AC-629A): 3.0 parts Antioxidant (BASF Japan hindered phenol antioxidant, Irganox 1010): 0.2 parts The obtained colored resin composition was charged from hopper 100 of manufacturing apparatus 10 shown in FIG. 1 and melt-kneaded in extruder 200 set at a temperature of 180°C. Next, the colored resin composition was extruded as a molten sheet from a calendar head. The sheet was flattened by passing through rollers 301, 302, and 303 while in contact with them. Thereafter, it passed through feed roller 401 and cooled by passing through cooling roller 400. Then, after passing between two guide rollers, it was cut to a predetermined length using cutter 501 to obtain a sheet-like evaluation sheet 1 having a thickness of 2.0 mm.

[0142] (Examples F-2 to F-14, Comparative Examples F-1 to F-6) Preparation of Colored Resin Compositions f-2 to f-14, f-101 to f-106) Colored resin compositions f-2 to f-14 and f-101 to f-106 were obtained in the same manner as in Example F-1, except that the naphthol-based azo pigment 1 in Example F-1 was changed as shown in Table 7. Each of the obtained colored resin compositions was extruded in the same manner to obtain evaluation sheets.

[0143] <Dispersibility> The resulting evaluation sheet was cut into 1 mm squares (approximately 0.001 g), sandwiched between two glass slides, and pressed at 90°C to create a test specimen. The entire specimen was observed under an optical microscope at 450x magnification, and evaluated according to the size and number of coarse particles according to the following criteria. A rating of "4" or "3" on the following scale indicates a practical level. The results are shown in Table 7. 4: No coarse particles of 10 μm or larger exist, and there are 0 to 9 coarse particles of 2 μm or larger exist 3: No coarse particles of 10 μm or larger exist, and there are 10 to 29 coarse particles of 2 μm or larger 2: There are no coarse particles of 10 μm or larger, and there are 30 or more coarse particles of 2 μm or larger 1: Coarse particles of 10 μm or larger are present

[0144] <Coloring power> The evaluation sheets prepared as described above were visually observed and evaluated according to the following criteria. The results are shown in Table 7. A rating of "3" or "2" on the following criteria is considered to be at a practical level. (Evaluation criteria for coloring strength) 3: Extremely high coloring strength compared to standard colored resin compositions 2: Higher coloring strength than the standard colored resin composition 1: Tinting strength is equal to or inferior to the standard colored resin composition

[0145] <Weather resistance> For the weather resistance test, the evaluation sheet was subjected to an accelerated weather resistance test using an ultra-accelerated weather resistance tester (Iwasaki Electric Co., Ltd., Eye Super Xenon Tester SUV-W151) at 90 mW / cm 2 The test was carried out for 96 hours (four 12-hour day and night cycles), and the color difference (ΔE*) before and after the weather resistance test was evaluated using a Konica Minolta CM-700d color difference meter. The results are shown in Table 7. A rating of "3" or "2" on the following scale is considered to be at a practical level. (Weather resistance evaluation criteria) 3: Color change before and after the test (ΔE*) is less than 2.5, good 2: The color change (ΔE*) before and after the test is 2.5 or more and less than 4, suitable for practical use 1: Color change before and after the test (ΔE*) is 4 or more, defective

[0146] [Table 7]

[0147] From the results in Tables 2 to 7, it can be seen that when the naphthol azo pigment of the present invention is used, paints, inks and colored resin compositions excellent in dispersibility, dispersion stability, tinting strength, light resistance and weather resistance can be obtained. On the other hand, the paint and ink using a pigment with a particle size smaller than the specified range in Comparative Example 1 did not have excellent initial viscosity or viscosity stability, and also lacked light resistance and weather resistance. The paint and ink using a pigment with an aspect ratio outside the specified range in Comparative Example 2 lacked viscosity stability. In Comparative Example 3, a pigment with a particle size larger than the specified range was used, so the paint, ink, and colored resin composition lacked coloring power. In addition, in Comparative Examples 4 and 5, conventional naphthol pigments with low lightfastness were used, so paints, inks, and colored resin compositions with excellent lightfastness and weather resistance could not be obtained.In Comparative Example 6, a quinacridone pigment was used, so paints, inks, and colored resin compositions with excellent tinting power, viscosity stability, and dispersibility could not be obtained.< / f> < / e> < / d> < / c>

Claims

1. A compound represented by the following general formula (1), having an average primary particle diameter of 90 nm or more and 1000 nm or less and an average primary particle aspect ratio of 1 or more and 3.3 or less: A naphthol-based azo pigment that satisfies the following condition 1 or 2: General formula (1) 【Chemical 1】 In general formula (1), R1 represents a hydrogen atom, an alkyl group, a halogen group, a nitro group, a carboxy group, a sulfo group, a phosphate group, a sulfamoyl group, a carbamoyl group, an alkylsulfamoyl group, or an alkylcarbamoyl group. R2 and R3 each independently represent a hydrogen atom, an alkoxy group, an alkyl group, a halogen group, a nitro group, a carboxy group, a sulfo group, a phosphate group, a sulfamoyl group, a carbamoyl group, an alkylsulfamoyl group, or an alkylcarbamoyl group. Condition 1: Either X1 or X2 is a carboxy group or a carbamoyl group, at least one of Y1, Y2 and Y3 is an alkoxy group or a halogen group, and the remainder of X1, X2, Y1, Y2 and Y3 are hydrogen atoms. Condition 2: Either X1 or X2 is an alkoxy group or a halogen group, at least one of Y1, Y2, and Y3 is a carboxy group or a carbamoyl group, and the remaining of X1, X2, Y1, Y2, and Y3 are hydrogen atoms.

2. 2. The naphthol azo pigment according to claim 1, wherein R1 is a hydrogen atom or an alkyl group, and R2 and R3 are hydrogen atoms.

3. A coloring composition comprising the naphthol azo pigment according to claim 1 or 2 and a dispersion medium.

4. A paint comprising the naphthol azo pigment according to claim 1 or 2, a resin, and a solvent.

5. An ink comprising the naphthol azo pigment according to claim 1 or 2, a resin, and a solvent.

6. An actinic ray-curable ink comprising the naphthol azo pigment according to claim 1 or 2 and a polymerizable compound.

7. A method for producing the naphthol azo pigment according to claim 1, comprising the steps of: A method for producing a naphthol-based azo pigment, comprising: subjecting a solution containing a coupler component represented by the following general formula (2) to a coupling reaction with a solution containing a diazonium salt represented by the following general formula (4) obtained by diazotizing an aromatic amine represented by the following general formula (3) in the presence of a water-soluble organic solvent, to obtain a compound represented by the general formula (1): 【Chemistry 2】 [In general formula (2), general formula (3), and general formula (4), R1 is a hydrogen atom, an alkyl group, a halogen group, a nitro group, a carboxy group, a sulfo group, a phosphate group, a sulfamoyl group, a carbamoyl group, an alkylsulfamoyl group, or an alkylcarbamoyl group. R2 and R3 each independently represent a hydrogen atom, an alkoxy group, an alkyl group, a halogen group, a nitro group, a carboxy group, a sulfo group, a phosphate group, a sulfamoyl group, a carbamoyl group, an alkylsulfamoyl group, or an alkylcarbamoyl group. [Z ｎ－ ] １／ｎ is an anion of any valence n (n is an integer from 1 to 3). X1, X2, Y1, Y2, and Y3 satisfy either the following condition 1 or condition 2. Condition 1: Either X1 or X2 is a carboxy group or a carbamoyl group, at least one of Y1, Y2 and Y3 is an alkoxy group or a halogen group, and the remainder of X1, X2, Y1, Y2 and Y3 are hydrogen atoms. Condition 2: Either X1 or X2 is an alkoxy group or a halogen group, at least one of Y1, Y2, and Y3 is a carboxy group or a carbamoyl group, and the remaining of X1, X2, Y1, Y2, and Y3 are hydrogen atoms.

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