Black azo pigment and colorant

Abstract

To provide a black azo pigment having a novel skeleton, which has sufficient blackness, is superior in durability such as solvent resistance, substantially does not contain halogen atoms in its structure, and does not absorb near-infrared radiation.SOLUTION: A black azo pigment comprises a compound represented by the following formula (1). In the formula, R1 represents an arylene group optionally having a substituent free of halogen atoms, and R2 and R3 each independently represent an aryl group optionally having a substituent free of halogen atoms.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to black azo pigments and colorants. [Background technology]

[0002] Conventionally, carbon black pigments and iron oxide pigments have been commonly used as black pigments in paints, printing inks, colorants for plastics, and the like. These black pigments, particularly carbon black pigments, show black color by absorbing all light in the visible light region (wavelength of about 380 to 780 nm) of sunlight, but in reality, they also absorb light in the near infrared region including the wavelength region of 800 to 1,400 nm. Since light in the near infrared region contributes greatly to heat, there is a problem that articles colored with the above-mentioned black pigments easily heat up when exposed to sunlight. In addition, as articles colored with black pigments, sophisticated products such as black matrices for color filters have appeared in recent years. For this reason, various studies have been conducted on black pigments that do not heat up even when exposed to sunlight, and colorants (coloring compositions) used to color articles black.

[0003] For example, Patent Documents 1 and 2 propose a black azo pigment that absorbs light in the visible region to show a black color but does not absorb light in the infrared region (infrared rays). Patent Documents 1 and 2 disclose that by using a colorant containing this black azo pigment, an article can be obtained that does not excessively increase in temperature even when exposed to direct sunlight, etc. In addition, they disclose that by using a black pigment dispersant, it is possible to significantly improve the fluidity of liquid materials such as inks and paints that contain pigment particles such as black azo pigments in a dispersed state, and it is also possible to suppress the aggregation of pigment particles, and it is possible to obtain a colored article with excellent optical density while preventing the generation of foreign matter. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 4-015265 [Patent Document 2] Patent No. 6615684 Summary of the Invention [Problem to be solved by the invention]

[0005] However, many of the general azo pigments have poor durability, such as poor heat resistance and solvent resistance, and also have the problem of being prone to insufficient blackness.

[0006] Compounds containing halogen atoms tend to generate harmful gases when burned. For this reason, black pigments used as black colorants for forming electronic materials such as black matrices for color filters and light-shielding films are also required to be halogen-free. However, the black azo pigment proposed in Patent Document 1 does not meet the halogen-free requirement because it contains chlorine atoms in its structure.

[0007] The black azo pigment proposed in Patent Document 2 has excellent solvent resistance and high blackness. However, when used in paint, there is a problem that sufficient heat shielding effect cannot be obtained because of poor solar reflectance. In addition, when used as a material for forming a black matrix for a color filter, a higher near-infrared non-absorption property is required, so it cannot be said that it is necessarily a suitable pigment.

[0008] The present invention has been made in consideration of the problems associated with the conventional techniques, and an object of the present invention is to provide a near-infrared non-absorbing black azo pigment having a novel skeleton which has sufficient blackness, is excellent in durability such as solvent resistance, and is substantially free of halogen atoms in its structure, and a colorant using the same. [Means for solving the problem]

[0009] The present invention has the following aspects. [1] A black azo pigment comprising a compound represented by the following formula (1): [ka] In the formula, R 1 represents an arylene group which may have a substituent not containing a halogen atom, R 2 and R 3 each independently represents an aryl group which may have a substituent not containing a halogen atom. [2] In the formula (1), R 3 The black azo pigment according to [1], wherein the black azo pigment is represented by the following formula (3-1) or (3-2): [ka] In the formula, R 4 represents an aryl group which may have a substituent not containing a halogen atom. [3] In the formula (1), R 2 The black azo pigment according to [1] or [2], wherein the black azo pigment is represented by the following formula (2-1), (2-2) or (2-3): [ka] In the formula, R 5 represents an alkoxy group or an alkyl group, a represents an integer of 0 to 5, and when a is 2 or more, multiple R 5 may be the same or different, R 6 represents an alkoxy group or an alkyl group, b represents an integer of 0 to 3, and when b is 2 or more, multiple R 6 may be the same or different, R 7 represents an alkoxy group or an alkyl group, c represents an integer of 0 to 7, and when c is 2 or more, multiple R 7 may be the same or different. [4] In the formula (3-1) or (3-2), R 4 The black azo pigment according to [2], wherein the black azo pigment is represented by the following formula (2-1), (2-2) or (2-3): [ka] In the formula, R 5represents an alkoxy group or an alkyl group, a represents an integer of 0 to 5, and when a is 2 or more, multiple R 5 may be the same or different, R 6 represents an alkoxy group or an alkyl group, b represents an integer of 0 to 3, and when b is 2 or more, multiple R 6 may be the same or different, R 7 represents an alkoxy group or an alkyl group, c represents an integer of 0 to 7, and when c is 2 or more, multiple R 7 may be the same or different. [5] The black azo pigment according to any one of [1] to [4], wherein the particles have a volume average particle diameter of 20 to 1,000 nm. [6] A colorant comprising the black azo pigment according to any one of [1] to [5]. [7] The colorant according to [6], which is used to form a black matrix for a color filter. [8] The colorant according to [6], which is used to form a light-shielding film. [9] The colorant according to [6], which is used as a paint. Effect of the Invention

[0010] According to the present invention, it is possible to provide a near-infrared non-absorbing black azo pigment having a novel skeleton which has sufficient blackness, excellent durability such as solvent resistance, and is substantially free of halogen atoms in its structure, and a colorant using the same. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described, however, the present invention is not limited to the following embodiment.

[0012] <Black azo pigment> A black azo pigment according to one embodiment of the present invention is made of a compound represented by the following formula (1).

[0013] [ka]

[0014] In the formula, R 1 represents an arylene group which may have a substituent not containing a halogen atom, R 2 and R 3 each independently represents an aryl group which may have a substituent not containing a halogen atom.

[0015] R 1 The arylene group in the above may have a ring skeleton consisting of only carbon atoms, or may contain a heteroatom in the ring skeleton. Examples of the heteroatom include a nitrogen atom, an oxygen atom, and a sulfur atom. The arylene group may be monocyclic or polycyclic. Examples of the arylene group include a phenylene group and a naphthylene group. Examples of the phenylene group include a p-phenylene group, an m-phenylene group, and an o-phenylene group. Examples of the naphthylene group include a 1,5-naphthylene group, a 1,8-naphthylene group, and a 2,3-naphthylene group.

[0016] Examples of the substituent that does not contain a halogen atom include a hydroxyl group, an alkoxy group, an alkyl group, an aryl group, -C(=O)-NH-R 8 (However, R 8 represents an aryl group.) and divalent substituents such as -NH-C(=O)-NH-. The divalent substituent is, for example, bonded to two of the carbon atoms constituting the ring skeleton of the arylene group, forming a ring together with those carbon atoms.

[0017] The number of carbon atoms in the alkoxy group as a substituent is, for example, 1 to 8. The alkyl group in the alkoxy group may be linear, branched, or cyclic. The alkoxy group may have a substituent that does not contain a halogen atom. The number of carbon atoms of the alkyl group as a substituent is, for example, 1 to 8. The alkyl group may be linear, branched, or cyclic. The alkyl group may have a substituent that does not contain a halogen atom.

[0018] The aryl group as a substituent may have a ring skeleton consisting of only carbon atoms, or may have a heteroatom in the ring skeleton. Examples of the heteroatom include those described above. The aryl group may be monocyclic or polycyclic. Examples of the aryl group include a phenyl group, a naphthyl group, and a 11H-benzo[a]carbazol-3-yl group. The aryl group may have a substituent that does not contain a halogen atom.

[0019] R 1 From the viewpoint of availability of raw materials, a phenylene group which may have a substituent which does not contain a halogen atom, or a naphthylene group which may have a substituent which does not contain a halogen atom is preferred.

[0020] R 2 and R 3 As the aryl group in the above, the same aryl groups as those mentioned above as the substituent can be mentioned. Examples of the substituent not containing a halogen atom which the aryl group may have include the same substituents not containing a halogen atom which the arylene group may have.

[0021] R 2 From the viewpoint of availability of raw materials, the group represented by the following formula (2-1), (2-2) or (2-3) is preferable.

[0022] [ka]

[0023] In the formula, R 5 represents an alkoxy group or an alkyl group, a represents an integer of 0 to 5, and when a is 2 or more, multiple R 5 may be the same or different, R 6 represents an alkoxy group or an alkyl group, b represents an integer of 0 to 3, and when b is 2 or more, multiple R 6 may be the same or different, R 7represents an alkoxy group or an alkyl group, c represents an integer of 0 to 7, and when c is 2 or more, multiple R 7 may be the same or different. R 5 , R 6 , R 7 The alkoxy group and the alkyl group in each of the above-mentioned groups are the same as the alkoxy group and the alkyl group as the substituent.

[0024] R 2 From the viewpoint of availability of raw materials, groups represented by the following formula (2-11), (2-12), (2-13) or (2-14) are more preferable.

[0025] [ka]

[0026] R 3 From the viewpoint of availability of raw materials, the group represented by the following formula (3-1) or (3-2) is preferable. In terms of cheaper raw materials, the group represented by formula (3-1) is more preferable, and in terms of symmetry as a black azo pigment, the group represented by formula (3-2) is more preferable.

[0027] [ka]

[0028] In the formula, R 4 represents an aryl group which may have a substituent not containing a halogen atom. R 4 As the above, R 2 The same can be mentioned. R 2 and R 4 may be the same or different.

[0029] R 3 As the alkyl group, a group represented by the following formula (3-11), (3-12), (3-13), (3-14) or (3-15) is more preferable.

[0030] [ka]

[0031] The compound represented by the formula (1) includes, in the formula (1), R 2 is a group represented by the formula (2-1), (2-2) or (2-3), and R 3 is preferably a compound represented by the above formula (3-1) or (3-2), 2 is a group represented by the formula (2-1), (2-2) or (2-3), and R 3 is a group represented by the above formula (3-11), (3-12), (3-13), (3-14) or (3-15).

[0032] Specific examples of the compound represented by formula (1) include compounds represented by the following formulas (A) to (L).

[0033] [ka]

[0034] [ka]

[0035] The black azo pigment of the present embodiment may contain impurities. Examples of impurities include those (unreacted raw materials, etc.) derived from the method for producing the black azo pigment, which will be described later. The content of impurities in the black azo pigment is preferably 1 mass % or less, and more preferably 0.1 mass % or less, based on the total mass of the black azo pigment. The content of impurities is measured by high performance liquid chromatography.

[0036] The black azo pigment of the present embodiment is made of the compound represented by the formula (1) above, and therefore has excellent blackness while being non-absorbent of near infrared rays. For example, by incorporating the black azo pigment of this embodiment into an alkyd / melamine baking paint, a coating film can be formed having a black value, preferably an optical density (OD value) of 2.2 or more, more preferably 2.5 or more, as shown in the examples described later.

[0037] Since the compound represented by the formula (1) does not contain a halogen atom in its molecular structure, the black azo pigment of the present embodiment does not substantially contain a halogen atom. "Substantially does not contain a halogen atom" means that the black azo pigment is halogen-free. The content of halogen atoms in the black azo pigment is preferably 100 ppm by mass or less, and more preferably 50 ppm by mass or less, based on the total mass of the black azo pigment. The content of halogen atoms is measured by an elemental analyzer. Pigments containing halogen atoms often cause problems, particularly when used as constituent materials for electronic materials, etc. The black azo pigment of the present embodiment is advantageous over the halogen-containing black azo pigment described in Patent Document 1 from the viewpoint of being halogen-free. Generally, organic pigments that have halogen atoms introduced into their molecular structure tend to have improved durability such as solvent resistance and heat resistance, so it is not necessarily easy to design a halogen-free organic pigment from the viewpoint of maintaining a high level of durability. In contrast, the compound represented by the above formula (1) has excellent durability, even though it does not contain halogen atoms in its molecular structure.

[0038] The black azo pigment of the present embodiment may be in a particulate form. In this specification, the particulate form includes a powder form. When the black azo pigment of the present embodiment is in the form of particles, the volume average particle diameter is preferably 20 to 1,000 nm. If the volume average particle diameter is within this range, the black pigment can be used without problems in various applications. It may be physically difficult to obtain a black pigment having a volume average particle diameter of less than 20 nm. On the other hand, if the volume average particle diameter is more than 1,000 nm, the coloring power may be insufficient when used as a colorant. To further increase the blackness and non-absorption of near-infrared rays, the volume average particle diameter of the black azo pigment is more preferably 20 to 300 nm.To further increase the blackness (OD value: 2.2 or more), the volume average particle diameter of the black azo pigment is even more preferably 20 to 100 nm. The volume average particle size is measured by dynamic light scattering (diameter equivalent to the diffusion coefficient, distribution standard: light intensity).

[0039] (Manufacturing method of black azo pigment) The black azo pigment of the present embodiment can be produced, for example, by the following production method A or B.

[0040] Manufacturing method A: H 2 NR 1 -NH-C(=O)-CH 3 Compounds represented by the formula (R 1 is R in the above formula (1). 1 The compound (X) is diazotized by a conventional method and subjected to a coupling reaction with 2-hydroxy-11H-benzo[a]carbazole-3-carboxamide to obtain an intermediate (X) represented by the following formula (X). Intermediate (X) is heated in the presence of an acid such as hydrochloric acid or acetic acid to hydrolyze the acetyl group to an amino group, and after cooling, is diazotized in a conventional manner to give R 3 -C(=O)-NH 2 Carboxamides represented by the formula (R 3 is R in the above formula (1). 3 This is the same as: (1) is subjected to a coupling reaction with the above-mentioned aryl group.

[0041] [ka] In the formula, R 1 and R 2 are R in the above formula (1), 1 and R 2 is the same as:

[0042] Manufacturing method B: H 2NR 1 -NH 2 The compound represented by the formula (1) is tetrazotized by a conventional method and then subjected to a coupling reaction with 2-hydroxy-11H-benzo[a]carbazole-3-carboxamide. 3 is a group represented by the above formula (3-2).

[0043] The H used in the above manufacturing method A 2 NR 1 -NH-C(=O)-CH 3 Examples of the compound represented by the formula (I) include aminoacetanilides such as 2'-aminoacetanilide, 3'-aminoacetanilide, 4'-aminoacetanilide, and 5'-amino-2'-methylacetanilide.

[0044] Examples of the 2-hydroxy-11H-benzo[a]carbazole-3-carboxamides used in the above-mentioned production methods A and B include 2-hydroxy-N-phenyl-11H-benzo[a]carbazole-3-carboxamide, 2-hydroxy-N-(4-methoxyphenyl)-11H-benzo[a]carbazole-3-carboxamide, 2-hydroxy-N-(4-methoxy-2-methylphenyl)-11H-benzo[a]carbazole-3-carboxamide, 2-hydroxy-N-(4-methoxy-2-methylphenyl)-11H-benzo[a]carbazole-3-carboxamide, Examples of such compounds include hydroxy-N-(2-oxo-2,3-dihydro-1H-benzo[d]imidazol-5-yl)-11H-benzo[a]carbazole-3-carboxamide, N-(1,3-dioxoisoindolin-5-yl)-2-hydroxy-11H-benzo[a]carbazole-3-carboxamide, and N-(9,10-dioxo-9,10-dihydroanthracen-1-yl)-2-hydroxy-11H-benzo[a]carbazole-3-carboxamide.

[0045] The H used in the above manufacturing method B 2 NR 1 -NH 2 Examples of the compound represented by the formula (1) include diaminonaphthalenes such as 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, and 2,3-diaminonaphthalene.

[0046] R used in the above manufacturing method B 3 -C(=O)-NH 2 Examples of the carboxamides represented by the formula (I) include the above-mentioned 2-hydroxy-11H-benzo[a]carbazole-3-carboxamides; 3-hydroxy-N-(1-naphthyl)-2-naphthamide, 3-hydroxy-N-(2-naphthyl)-2-naphthamide, 3-hydroxy-N-(2-oxo-2,3-dihydro-1H-1,3-benzodiazol-5-yl)naphthalene-2-carboxamide, N- Examples of such naphthol carboxamides include (1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl)-3-hydroxynaphthalene-2-carboxamide, N-(9-ethyl-9H-carbazol-3-yl)-3-hydroxynaphthalene-2-carboxamide, and 3-hydroxy-N-(2-methoxydibenzo[b,d]furan-3-yl)naphthalene-2-carboxamide.

[0047] The diazotization reaction or tetrazo reaction is preferably carried out in water or an organic solvent. Examples of the organic solvent include alcohols such as methanol and ethanol, aromatic solvents such as toluene, xylene, o-dichlorobenzene, nitrobenzene, and o-nitrotoluene, and polar solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone. These organic solvents can be used alone or in combination of two or more. After the coupling reaction, the reaction product may be dried, washed, microparticulated, etc., if necessary.

[0048] The reaction product obtained as described above is a pigment exhibiting a dark color such as black or dark purple, dark brown, or dark green, and has good solvent resistance, light resistance, heat resistance, water resistance, and chemical resistance, high coloring power, and is a pigment exhibiting properties that are particularly excellent in heat resistance. By further microparticulating the pigment, a hue with even greater clarity, brightness, and transparency can be imparted to the pigment. The preferred range of the volume average particle size of the finely divided pigment is as described above.

[0049] As for the method of microparticulation, several methods will be exemplified below, but the present invention is not limited to these methods. (1) Solvent-salt milling method, in which pigments are ground. In this method, a pigment, a water-soluble inorganic salt, and a water-soluble organic solvent are charged in a kneader in an appropriate ratio, and the contents are compressed and kneaded for a certain period of time while controlling the temperature, and then the kneaded product is poured into a heated dilute aqueous sulfuric acid solution, stirred, filtered, and washed with water to remove the water-soluble inorganic salt and the water-soluble organic solvent, and then dried with hot air, etc. Examples of the water-soluble inorganic salt include sodium chloride, sodium sulfate, etc. Examples of the water-soluble organic solvent include ethylene glycol, diethylene glycol, polyethylene glycol, etc.

[0050] (2) Dry milling method using a ball mill or a vibrating mill. In this method, grinding media such as steel balls and steel rods are used, and, if necessary, grinding aids such as inorganic salts such as sodium chloride, sodium sulfate, and aluminum nitrate are used.

[0051] (3) Acid paste method. In this method, the crude pigment is dissolved in a good solvent such as sulfuric acid or polyphosphoric acid, and the solution is then poured into a poor solvent such as water to reprecipitate the pigment. Although the desired fine pigment can be obtained by simply washing the thus obtained pigment thoroughly with water, the desired pigment can be obtained reliably by pigmenting the pigment with an appropriate organic solvent and regulating the particle size.

[0052] (4) A method for producing a fine pigment by using two or more types of diazotized intermediate (X) or using one or more other coupling components in combination when subjecting a diazotized intermediate (X) to a coupling reaction with a coupling component (a carboxamide) in the above-mentioned production method A, thereby inhibiting the growth of the pigment particles produced. Although the desired micronized pigment may be obtained only by this method, it is more preferable to use the solvent-salt milling method of (1) in combination with the method of (4) above.

[0053] The black azo pigment of this embodiment has, as optical properties, the property of reflecting or transmitting infrared rays and heat rays of sunlight, and has excellent fastness as pigment properties, particularly excellent heat resistance. The black azo pigment of this embodiment can be used as a colorant for a coloring composition for paints, a coloring composition for plastics, a coloring composition for fibers, a coloring composition for printing inks, a coloring composition for image recording, a coloring composition for image display, or a coloring composition for pigment resist dyes. These coloring compositions are used as coloring compositions containing a pigment component containing the black azo pigment of this embodiment dispersed in a liquid dispersion medium or a solid dispersion medium depending on the application and the form of use.

[0054] <Colorant> The colorant (coloring composition) according to an embodiment of the present invention contains the black azo pigment of the present invention.

[0055] The colorant of this embodiment may contain other pigment components other than the black azo pigment of the present invention. Examples of other pigment components include other black pigments, colored pigments, white pigments, and extender pigments other than the black azo pigment of the present invention. Two or more other pigment components may be used in combination according to the target color. Other pigment components may contain halogen atoms, but preferably do not contain them. The content of halogen atoms in other pigment components is preferably 100 mass ppm or less, more preferably 50 mass ppm or less, based on the total mass of other pigment components.

[0056] The colorant of this embodiment may contain a liquid dispersion medium or a solid dispersion medium in order to disperse the pigment component. That is, the colorant of the present embodiment may be, depending on the purpose, application, method of use, etc., (i) a liquid colorant composition in which a pigment component containing the black azo pigment of the present invention is contained in a liquid dispersion medium, or (ii) a solid colorant composition in which a pigment component containing the black azo pigment of the present invention is contained in a solid dispersion medium. Such a colorant can be prepared, for example, by dispersing pigment components including the black azo pigment of the present invention in a liquid dispersion medium or a solid dispersion medium.

[0057] The liquid dispersion medium may be a liquid by itself or a liquid that becomes liquid by containing a solvent or water. The liquid dispersion medium may contain at least one film-forming material selected from the group consisting of polymers which may have reactive groups, oligomers which may have reactive groups, and monomers which may have reactive groups.

[0058] The liquid colorant composition is mainly used as a colorant to be applied to the surface of an article, to impregnate an article, or to be drawn or printed on the surface of an article. That is, the liquid colorant composition can be used in various applications such as paint, a colorant for plastics, a fiber colorant, a printing ink, stationery, a colorant for image recording, or a colorant for image display. It is preferable to prepare a high-concentration pigment processed product (high-concentration pigment dispersion) in advance, in which a pigment component containing the black azo pigment of the present invention is dispersed in a liquid dispersion medium at a higher concentration than that of the colorant composition, because this makes it easy to manufacture colorant compositions for various applications. Such high-concentration pigment processed products are generally used as "base colors" or "base inks."

[0059] Examples of the solid dispersion medium include thermoplastic resins, thermosetting resins, waxes, fatty acid amides, fatty acid metal soaps, etc. These solid dispersion media can be used alone or in combination of two or more.

[0060] The solid coloring agent composition is mainly used as a coloring agent for coloring plastic products and synthetic fibers. If a high-concentration pigment processed product (high-concentration pigment dispersion) in which the pigment component containing the black azo pigment of the present invention is dispersed in a solid dispersion medium at a higher concentration than the coloring agent composition is prepared in advance, it is preferable because coloring agent compositions for various uses can be easily manufactured. Such high-concentration pigment processed products are used in known product forms such as master powder, masterbatch, or entirely colored color pellets.

[0061] The coloring agent of the present embodiment may contain a halogen atom due to the pigment component and other components, but preferably does not contain it. The content of the halogen atom in the coloring agent is preferably 100 mass ppm or less, more preferably 50 mass ppm or less, based on the total mass of the coloring agent.

[0062] According to the coloring agent of the present embodiment, an article or the like can be colored black with an extremely high blackness degree. Also, depending on the concentration, the blackness degree can be increased compared to the case of using carbon black. Therefore, the coloring agent of the present embodiment is useful, for example, as a material for forming a black matrix for a color filter, a material for forming a light-shielding film, or a paint.

[0063] Hereinafter, for further details of the coloring agent of the present embodiment, the coloring agent for a black matrix (hereinafter also referred to as BM) of a color filter (hereinafter also referred to as CF) will be described as a representative example. The coloring agent for BM is typically a pigment dispersion in which a pigment component is dispersed in a liquid containing a film-forming material. To prepare a BM colorant, for example, first, a pigment component containing the black azo pigment of the present invention is added to a liquid containing a film-forming material and premixed. Then, a dispersion treatment is performed to obtain a BM colorant. More specifically, the pigment component that has been uniformly ground using a dispersing machine such as a vertical media dispersing machine, a horizontal media dispersing machine, or a ball mill is added to and mixed with a liquid containing a film-forming material to obtain a BM colorant. Alternatively, the black azo pigment and the pigment dispersant are dissolved in sulfuric acid or the like, and the resulting solution is mixed with water to precipitate and separate a pigment composition containing the black azo pigment and the pigment dispersant as a solid solution or a co-precipitate. The separated pigment composition is added to a liquid containing a film-forming material, mixed, and then ground and dispersed using a horizontal wet media disperser (bead mill) such as a Dyno Mill. A BM colorant can also be obtained in this manner.

[0064] The liquid containing the film-forming material used to prepare the BM colorant can be a solution of a film-forming polymer contained in a known pigment dispersion for CF. The liquid medium used in the liquid containing the film-forming material can be an organic solvent, water, or a mixture of an organic solvent and water. As the pigment dispersant, known ones can be used, and examples thereof include the pigment dispersants and polymer dispersants described in Japanese Patent No. 6745777. The pigment colorant for BM may contain known additives such as a dispersing agent, a leveling agent, and an adhesion agent, if necessary.

[0065] By using the pigment colorants for the BM described above, including the black azo pigment, it is possible to form the BM of the CF that is substantially electrically insulating. The BM can be formed on the CF substrate by, for example, using a colorant for the BM, a method such as photolithography, laser ablation, inkjet printing, printing, transfer, or pasting. Thereafter, chromatic pixels can be further formed on the CF substrate on which the BM has been formed, using a known coloring agent for forming chromatic pixels.

[0066] The film thickness of the BM is, for example, 0.5 to 3 μm, and usually 1 to 2 μm. By using the pigment colorant for BM, it is possible to form a BM with sufficient optical density. The optical density of the BM is, for example, 1.6 or more, preferably 2.0 or more, and more preferably 2.2 or more.

[0067] The BM can also function as a spacer. Specific methods for making the BM function as a spacer include a method of forming the BM itself thick, a method of stacking pixels on the BM, a method of stacking a colorless resin film on the BM, etc. In any method, it is preferable to set the film thickness to about 5 to 10 μm. EXAMPLES

[0068] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" and "%" are by mass unless otherwise specified.

[0069] (Synthesis Example 1) Preparation of Intermediate (X-1) A solution (1) was prepared by dissolving 61.2 parts of 2-hydroxy-N-(4-methoxyphenyl)-11H-benzo[a]carbazole-3-carboxamide, 12.8 parts of sodium hydroxide, and 87 parts of sodium acetate trihydrate in 1000 parts of methanol. Separately, 24 parts of 4'-aminoacetanilide and 60 parts of 35% hydrochloric acid were added to 100 parts of water, and the mixture was stirred for 30 minutes at 0 to 10° C. A solution of 12 parts of sodium nitrite dissolved in 24 parts of water was added thereto to obtain a diazonium salt solution (2). Solution (2) was added to solution (1), and a coupling reaction was carried out for 5 hours at 20 to 30° C. After filtration and washing with water, the mixture was dried to obtain 82 parts of intermediate (X-1) represented by the following formula (X-1).

[0070] [ka]

[0071] (Synthesis Example 2) Production of Intermediate (X-2) 85 parts of intermediate (X-2) represented by the following formula (X-2) was obtained in the same manner as in Synthesis Example 1 described above, except that 63.4 parts of 2-hydroxy-N-(4-methoxy-2-methylphenyl)-11H-benzo[a]carbazole-3-carboxamide was used instead of 61.2 parts of 2-hydroxy-N-(4-methoxy-2-methylphenyl)-11H-benzo[a]carbazole-3-carboxamide.

[0072] [ka]

[0073] (Synthesis Example 3) Production of Intermediate (X-3) 86 parts of intermediate (X-3) represented by the following formula (X-3) was obtained in the same manner as in Synthesis Example 1 described above, except that 65.3 parts of 2-hydroxy-N-(2-oxo-2,3-dihydro-1H-benzo[d]imidazol-5-yl)-11H-benzo[a]carbazole-3-carboxamide was used instead of 61.2 parts of 2-hydroxy-N-(4-methoxyphenyl)-11H-benzo[a]carbazole-3-carboxamide.

[0074] [ka]

[0075] <Production of black azo pigment> (Example 1) Production of black azo pigment (A) 54.4 parts of intermediate (X-1) was dispersed in 300 parts of acetic acid, 41.7 parts of 35% hydrochloric acid was added, and the mixture was stirred at 90 to 100° C. for 4 hours to hydrolyze the acetyl group. The mixture was cooled to 0 to 10° C., and a solution of 7.6 parts of sodium nitrite dissolved in 15 parts of water was added to prepare a diazonium salt suspension. Separately, a coupling component solution was prepared by dissolving 38.2 parts of 2-hydroxy-N-(4-methoxyphenyl)-11H-benzo[a]carbazole-3-carboxamide in 16 parts of sodium hydroxide and 900 parts of methanol. The above diazonium salt suspension was added to this, and a coupling reaction was carried out at 0 to 10°C for 1 hour and at 20 to 30°C for 5 hours. After filtration and washing with water, the solution was dried to obtain 85 parts of a black azo pigment (A) represented by the following formula (A).

[0076] [ka]

[0077] Mass spectrometry using MALDI (matrix-assisted laser desorption / ionization) detected a peak with a molecular weight of 894.93. The raw materials used and the results of mass spectrometry confirmed that a compound with the desired structure was obtained.

[0078] (Example 2) Production of black azo pigment (B) Instead of 54.4 parts of intermediate (X-1), 55.8 parts of intermediate (X-2) were used, and instead of 38.2 parts of 2-hydroxy-N-(4-methoxy-2-methylphenyl)-11H-benzo[a]carbazole-3-carboxamide, 39.7 parts of 2-hydroxy-N-(4-methoxy-2-methylphenyl)-11H-benzo[a]carbazole-3-carboxamide were used, except that 87 parts of black azo pigment (B) represented by the following formula (B) was obtained in the same manner as in Example 1 described above. A peak of molecular weight 923.0 was detected by mass spectrometry using MALDI. It was confirmed that a compound of the desired structure was obtained from the raw materials used and the results of mass spectrometry.

[0079] [ka]

[0080] (Example 3) Production of black azo pigment (C) Instead of 54.4 parts of intermediate (X-1), 57 parts of intermediate (X-3) were used, and instead of 38.2 parts of 2-hydroxy-N-(4-methoxyphenyl)-11H-benzo[a]carbazole-3-carboxamide, 40.8 parts of 2-hydroxy-N-(2-oxo-2,3-dihydro-1H-benzo[d]imidazol-5-yl)-11H-benzo[a]carbazole-3-carboxamide were used. Except for this, 89 parts of black azo pigment (C) represented by the following formula (C) was obtained in the same manner as in Example 1 described above. A peak of molecular weight 946.94 was detected by mass spectrometry using MALDI. It was confirmed that the compound of the desired structure was obtained from the raw materials used and the results of mass spectrometry.

[0081] [ka]

[0082] (Example 4) Production of black azo pigment (D) A solution (3) was prepared by dissolving 76.5 parts of 2-hydroxy-N-(4-methoxyphenyl)-11H-benzo[a]carbazole-3-carboxamide and 24 parts of sodium hydroxide in 1200 parts of methanol. Separately, 15.8 parts of 1,5-diaminonaphthalene and 62.5 parts of 35% hydrochloric acid were added to 120 parts of water, and the mixture was stirred for 30 minutes at 0 to 10° C. A solution of 15.2 parts of sodium nitrite dissolved in 30 parts of water was added thereto to obtain a tetrazonium salt solution (4). Solution (4) was added to solution (3), and a coupling reaction was carried out at 20 to 30°C for 5 hours. After filtration and washing with water, the mixture was dried to obtain 85 parts of a black azo pigment (D) represented by the following formula (D). A peak of molecular weight 944.99 was detected by mass spectrometry using MALDI. It was confirmed that a compound of the desired structure was obtained based on the raw materials used and the results of mass spectrometry.

[0083] [ka]

[0084] (Example 5) Production of black azo pigment (E) 83 parts of a black azo pigment (E) represented by the following formula (E) was obtained in the same manner as in Example 4, except that 79.3 parts of 2-hydroxy-N-(4-methoxy-2-methylphenyl)-11H-benzo[a]carbazole-3-carboxamide was used instead of 76.5 parts of 2-hydroxy-N-(4-methoxy-2-methylphenyl)-11H-benzo[a]carbazole-3-carboxamide. A peak of molecular weight 973.06 was detected by mass spectrometry using MALDI. It was confirmed that a compound of the desired structure was obtained from the raw materials used and the results of mass spectrometry.

[0085] [ka]

[0086] (Example 6) Production of black azo pigment (F) 94 parts of a black azo pigment (F) represented by the following formula (F) was obtained in the same manner as in Example 4 described above, except that 81.7 parts of 2-hydroxy-N-(4-methoxyphenyl)-11H-benzo[a]carbazole-3-carboxamide was used instead of 76.5 parts of 2-hydroxy-N-(2-oxo-2,3-dihydro-1H-benzo[d]imidazol-5-yl)-11H-benzo[a]carbazole-3-carboxamide was used. A peak of molecular weight 977.00 was detected by mass spectrometry using MALDI. It was confirmed that a compound of the desired structure was obtained from the raw materials used and the results of mass spectrometry.

[0087] [ka]

[0088] (Example 7) Production of black azo pigment (G) Except for using 31.3 parts of 3-hydroxy-N-(1-naphthyl)-2-naphthamide instead of 38.2 parts of 2-hydroxy-N-(4-methoxyphenyl)-11H-benzo[a]carbazole-3-carboxamide, 74 parts of black azo pigment (G) represented by the following formula (G) was obtained in the same manner as in Example 1 described above. A peak of molecular weight 825.89 was detected by mass spectrometry using MALDI. It was confirmed that a compound of the desired structure was obtained based on the raw materials used and the results of mass spectrometry.

[0089] [ka]

[0090] (Example 8) Production of black azo pigment (H) Except for using 31.3 parts of 3-hydroxy-N-(1-naphthyl)-2-naphthamide instead of 39.7 parts of 2-hydroxy-N-(4-methoxy-2-methylphenyl)-11H-benzo[a]carbazole-3-carboxamide, 76 parts of black azo pigment (H) represented by the following formula (H) was obtained in the same manner as in Example 2 described above. A peak of molecular weight 839.91 was detected by mass spectrometry using MALDI. It was confirmed that a compound of the desired structure was obtained based on the raw materials used and the results of mass spectrometry.

[0091] [ka]

[0092] (Example 9) Preparation of black azo pigment (I) Instead of 40.8 parts of 2-hydroxy-N-(2-oxo-2,3-dihydro-1H-benzo[d]imidazol-5-yl)-11H-benzo[a]carbazole-3-carboxamide, 31.3 parts of 3-hydroxy-N-(1-naphthyl)-2-naphthamide were used. Otherwise, in the same manner as in Example 3 described above, 77 parts of a black azo pigment (I) represented by the following formula (I) were obtained. By mass spectrometry using MALDI, a peak with a molecular weight of 851.88 was detected. From the raw materials used and the results of mass spectrometry, it was confirmed that a compound with the target structure was obtained.

[0093] [Chemical formula]

[0094] (Example 10) Production of black azo pigment (J) Instead of 38.2 parts of 2-hydroxy-N-(4-methoxyphenyl)-11H-benzo[a]carbazole-3-carboxamide, 31.9 parts of 3-hydroxy-N-(2-oxo-2,3-dihydro-1H-1,3-benzodiazol-5-yl)naphthalene-2-carboxamide were used. Otherwise, in the same manner as in Example 1 described above, 76 parts of a black azo pigment (J) represented by the following formula (J) were obtained. By mass spectrometry using MALDI, a peak with a molecular weight of 831.85 was detected. From the raw materials used and the results of mass spectrometry, it was confirmed that a compound with the target structure was obtained.

[0095] [Chemical formula]

[0096] (Example 11) Production of black azo pigment (K) Instead of 39.7 parts of 2-hydroxy-N-(4-methoxy-2-methylphenyl)-11H-benzo[a]carbazole-3-carboxamide, 31.9 parts of 3-hydroxy-N-(2-oxo-2,3-dihydro-1H-1,3-benzodiazol-5-yl)naphthalene-2-carboxamide was used. Otherwise, in the same manner as in Example 2 described above, 77 parts of a black azo pigment (K) represented by the following formula (K) was obtained. By mass spectrometry using MALDI, a peak with a molecular weight of 845.88 was detected. From the raw materials used and the results of mass spectrometry, it was confirmed that a compound with the target structure was obtained.

[0097] [Chemical formula]

[0098] (Example 12) Production of black azo pigment (L) Instead of 40.8 parts of 2-hydroxy-N-(2-oxo-2,3-dihydro-1H-benzo[d]imidazol-5-yl)-11H-benzo[a]carbazole-3-carboxamide, 31.9 parts of 3-hydroxy-N-(2-oxo-2,3-dihydro-1H-1,3-benzodiazol-5-yl)naphthalene-2-carboxamide was used. Otherwise, in the same manner as in Example 3 described above, 80 parts of a black azo pigment (L) represented by the following formula (L) was obtained. By mass spectrometry using MALDI, a peak with a molecular weight of 857.85 was detected. From the raw materials used and the results of mass spectrometry, it was confirmed that a compound with the target structure was obtained.

[0099] [Chemical formula]

[0100] (Comparative Example 1) Production of black azo pigment (M) According to the method described in Patent Document 1, a black azo pigment (M) represented by the following formula (M) was produced.

[0101] [Chemical formula]

[0102] (Comparative Example 2) Production of black azo pigment (N) According to the method described in Patent Document 2, a black azo pigment (N) represented by the following formula (N) was produced.

[0103] [ka]

[0104] (Comparative Example 3) Production of black azo pigment (O) According to a conventional method, a black azo pigment (O) represented by the following formula (O) was produced.

[0105] [ka]

[0106] Comparative Example 4 As the pigment of Comparative Example 4, carbon black (brand "#45B", manufactured by Mitsubishi Chemical Corporation) was prepared.

[0107] <Evaluation> (Paint preparation) Using the pigments of each example, the components were mixed according to the formulation shown below, and the mixture was dispersed for 90 minutes using a paint conditioner to prepare paints. Pigment 1.5 parts Product name: "Super Beckamin J-820" (*1) 8.5 parts Product name: "Futarukid 133~60" (*2) 17.0 parts 5.0 parts xylene / 1-butanol (2 / 1 mass ratio) mixed solvent (*1) Butylated melamine resin (manufactured by Dainippon Ink and Chemicals) (*2) Short-oil alkyd resin made from coconut oil (manufactured by Hitachi Chemical)

[0108] (Making of colored paper) The prepared paint was applied to a drawing paper using an applicator (3 mil) and then baked at 140° C. for 30 minutes to form a coating film with a thickness of about 20 μm, thereby obtaining a drawing paper with a coating film.

[0109] (Blackness) Using a spectrophotometer (product name "CM-3600A", manufactured by Konica Minolta), the CIE three color stimulus values ​​of the above-mentioned color-developing paper were measured, and the optical density (OD value) of the coating film was calculated. The blackness was then evaluated according to the following criteria. The evaluation results are shown in Table 1. ○: Very high blackness (OD value: 2.5 or more). △: High blackness (OD value: 2.2 or more and less than 2.5). ×: Low blackness (OD value: less than 2.2).

[0110] (Solvent resistance) One part of the pigment of each example was added to 10 parts of nitrobenzene and boiled. The presence or absence of bleeding was then visually observed, and the solvent resistance was evaluated according to the following criteria. The evaluation results are shown in Table 1. ○: Almost no bleeding. △: Significant bleeding. ×: Almost completely dissolved.

[0111] (Near infrared properties) Using a spectrophotometer (product name "U-4100", manufactured by Hitachi High-Technologies Corporation), the reflectance of the coating film formed on the aforementioned colored paper was measured, and the near-infrared properties were evaluated according to the following criteria. The higher the reflectance of light with a wavelength of 800 nm, the better the non-absorption of near-infrared rays. The evaluation results are shown in Table 1. ◯: The reflectance of light with a wavelength of 800 nm is 50% or more. △: The reflectance of light with a wavelength of 800 nm is 10% or more and less than 50%. ×: The reflectance of light with a wavelength of 800 nm is less than 10%.

[0112] (halogen) For each example pigment, the pigments not containing halogen atoms were marked with an ◯, and the pigments containing halogen atoms were marked with an X. The evaluation results are shown in Table 1.

[0113] [Table 1]

[0114] The black azo pigments (A) to (L) of Examples 1 to 12 did not contain halogen atoms, had high blackness, and were excellent in solvent resistance and near-infrared properties.

[0115] <Preparation of black pigment dispersion> Example 13 [Preparation of fine powder of black pigment] In a kneader equipped with a pressure lid, 100 parts of the black azo pigment (D) of Example 4, 500 parts of sodium chloride powder, and 50 parts of diethylene glycol were charged. After premixing until a uniformly wetted mass was formed, the pressure lid was closed and a pressure of 6 kg / cm was applied. 2 The contents were kneaded and milled for 2 hours while controlling the temperature to 92-98°C while pressing down with a pressure washer. The milled product obtained was placed in 3,000 parts of water heated to 80°C and stirred for 1 hour, after which it was filtered and washed with water to remove sodium chloride and diethylene glycol, and a press cake was obtained. The press cake obtained was dried and pulverized to obtain a fine powder of the black azo pigment (D). Separately, a nonionic surfactant (200% of the pigment) was added to the press cake, and the mixture was diluted with water, followed by ultrasonic dispersion to prepare a pigment dispersion. The volume average particle diameter of the fine particles in the pigment dispersion was measured using a particle size measuring device (Model N-4, manufactured by Coulter) and was approximately 90 nm. The volume average particle diameter of the fine particles in the pigment dispersion can be regarded as the volume average particle diameter of the finely divided powder.

[0116] [Preparation of black pigment dispersion] 25 parts of a micronized powder of a black azo pigment (D), 1.5 parts of the following pigment dispersant (P) described in Japanese Patent No. 6745777, 10 parts of a benzyl methacrylate / methacrylic acid / 2-hydroxyethyl methacrylate copolymer (molar ratio: 60 / 20 / 20, weight average molecular weight 30,000), 5.5 parts of a basic polymer dispersant (trade name "DISPERBYK-2001", manufactured by BYK-Chemie, solid content 46%), and 65 parts of propylene glycol-1-monomethyl ether-2-acetate were mixed. After premixing, dispersion treatment was carried out using a horizontal bead mill to obtain a black pigment dispersion (Example 13).

[0117]

Chemical formula

[0118] <Formation and Evaluation of CF's BM Pattern> (Example 14) (1) Preparation of Photosensitive Black Resist Ink 40 parts of the black pigment dispersion obtained in Example 13, 5 parts of a 60% propylene glycol-1-monomethyl ether-2-acetate solution of an acrylated acrylic polyol photosensitive resin, 2 parts of trimethylolpropane triacrylate, 3 parts of dipentaerythritol hexaacrylate, 1 part of a photopolymerization initiator (ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetoxime), trade name "Irgacure OXE02", manufactured by BASF), and 51 parts of propylene glycol-1-monomethyl ether-2-acetate were blended. After sufficiently stirring uniformly using a high-speed stirrer, filtration was carried out through a filter with a pore size of 3 μm to prepare a photosensitive black resist ink.

[0119] (2) Evaluation of Black Coating Film (Resist Film) The photosensitive black resist ink was applied onto a glass substrate using a spin coater. After preliminary drying at 60 °C, pre-baking was carried out. After exposure using an ultra-high pressure mercury lamp with a light quantity of 400 mJ / cm², post-baking was carried out at 230 °C for 30 minutes to form a black coating film with a thickness of 2 μm. The transmittance of the black coating film formed was 20% or less for light from the long wavelength side of the visible light region to around 710 nm, and the transmittance of light at 780 nm reached 85%, after which it gradually increased and reached equilibrium. In particular, the transmittance of light in the range of 580 to 625 nm was extremely low, at 5% or less. The volume resistivity of the black coating film formed was 10 14 The resistance was found to be over Ω·cm, indicating that the coating is highly insulating.

[0120] (3) BM pattern formation A photosensitive black resist ink was applied onto a glass substrate using a spin coater, and then prebaked at 80°C for 10 minutes to form a black coating film with a thickness of 2 μm. Using an ultra-high pressure mercury lamp, the substrate was exposed to light at a dose of 100 mJ / cm through a negative photomask pattern of the BM pattern. After development with an alkaline developer, the substrate was washed with water and dried to form a BM pattern (BM film).

[0121] Since the formed BM film is a highly insulating coating film, it can be used, for example, as a BM film to maintain the thickness of the liquid crystal layer in place of a spacer, and can be used to construct liquid crystals in IPS and COA modes, etc. In addition, since it sufficiently absorbs visible light up to the long wavelength region, it can be suitably used as the BM for LCD panels that use LED backlights.

[0122] (4) Preparation of red, green, blue, yellow, and purple pigment dispersions Pigment dispersions of each color were prepared in the same manner as in Example 13 described above, except that PR254 (diketopyrrolopyrrole red pigment), PR177 (anthraquinone red pigment), PG36 (copper phthalocyanine green pigment), PB15:6 (ε-type copper phthalocyanine blue pigment), PY185 (yellow pigment), and PV23 (dioxazine violet pigment) were used instead of the black azo pigment (D) in Example 4, and a known pigment derivative having a sulfone group was used.

[0123] (5) Preparation of photosensitive resist inks of each color A pigment dispersion using PR254 and a pigment dispersion using PR177 were mixed in a ratio of 8:2 to obtain a blend. A photosensitive red resist ink was prepared in the same manner as the photosensitive black resist ink described above, except that the resulting blend was used instead of the black pigment dispersion.

[0124] A pigment dispersion using PG36 and a pigment dispersion using PY185 were mixed in a ratio of 6:4 to obtain a blend. A photosensitive green resist ink was prepared in the same manner as the photosensitive black resist ink described above, except that the blend obtained was used instead of the black pigment dispersion.

[0125] Furthermore, a pigment dispersion using PB15:6 and a pigment dispersion using PV23 were mixed in a ratio of 8:2 to obtain a blend. A photosensitive blue resist ink was prepared in the same manner as the photosensitive black resist ink described above, except that the blend obtained was used instead of the black pigment dispersion.

[0126] (6) Formation of RGB pixels on CF The glass substrate on which the BM was formed was set on a spin coater. The prepared photosensitive red resist ink was spin-coated onto the glass substrate, and then pre-baked at 80°C for 10 minutes. Using a proximity exposure machine equipped with an ultra-high pressure mercury lamp, 100 mJ / cm was applied through a photomask with a mosaic pattern. 2 The substrate was exposed to light at a light intensity of 10 ... [Industrial Applicability]

[0127] The black azo pigment of the present invention is useful as a material for producing products that require a high degree of blackness, such as the black matrix of a color filter, a light-shielding film, etc. In addition, since it is a near-infrared non-absorbing pigment, it is also useful as a heat ray non-absorbing black pigment for which carbon black, etc. are inappropriate.

Claims

1. A black azo pigment comprising a compound represented by the following formula (1): 【Chemistry 1】 In the formula, R １ represents an arylene group which may have a substituent not containing a halogen atom, R ２ and R ３ each independently represents an aryl group which may have a substituent not containing a halogen atom.

2. In the formula (1), R ３ The black azo pigment according to claim 1, wherein the black azo pigment is represented by the following formula (3-1) or (3-2): 【Chemistry 2】 In the formula, R ４ represents an aryl group which may have a substituent not containing a halogen atom.

3. In the formula (1), R ２ The black azo pigment according to claim 1, wherein is represented by the following formula (2-1), (2-2) or (2-3): 【Chemistry 3】 In the formula, R ５ represents an alkoxy group or an alkyl group, a represents an integer of 0 to 5, and when a is 2 or more, multiple R ５ may be the same or different, R ６ represents an alkoxy group or an alkyl group; b represents an integer of 0 to 3; when b is 2 or more, multiple R ６ may be the same or different, R ７ represents an alkoxy group or an alkyl group, c represents an integer of 0 to 7, and when c is 2 or more, multiple R ７ may be the same or different.

4. In the formula (3-1) or (3-2), R ４ The black azo pigment according to claim 2, wherein is represented by the following formula (2-1), (2-2) or (2-3): 【Chemistry 4】 In the formula, R ５ represents an alkoxy group or an alkyl group, a represents an integer of 0 to 5, and when a is 2 or more, multiple R ５ may be the same or different, R ６ represents an alkoxy group or an alkyl group; b represents an integer of 0 to 3; when b is 2 or more, multiple R ６ may be the same or different, R ７ represents an alkoxy group or an alkyl group, c represents an integer of 0 to 7, and when c is 2 or more, multiple R ７ may be the same or different.

5. 2. The black azo pigment according to claim 1, wherein the particles have a volume average particle size of 20 to 1,000 nm.

6. A colorant comprising the black azo pigment according to any one of claims 1 to 5.

7. 7. The colorant according to claim 6, which is used to form a black matrix for a color filter.

8. The colorant according to claim 6, which is used to form a light-shielding film.

9. The colorant according to claim 6, which is used as a paint.

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