JP6884622B2 - Benzoazole compounds or salts thereof, and pigment compositions containing them. - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention relates to a coumarin compound or a salt thereof used for a resist for a color filter used for manufacturing a liquid crystal display or an image sensor, an ink for inkjet, and a pigment composition containing the compound and having excellent fluidity and transparency. Regarding.

Pigments have been used as colorants for paints and printing inks, and in recent years, resists for color filters and ink jet inks. Pigments have various properties such as heat resistance, weather resistance, and migration resistance, and are superior to dyes in terms of toughness. On the other hand, pigments agglomerate, precipitate, increase viscosity over time, and are different from each other when made into a composition. It has potential problems such as color coding when mixed with pigments.

Recently, in order to achieve high contrast of liquid crystal displays, miniaturization of image pickup elements, high coloring and high sharpening of inkjet inks, etc., there is a demand for finer pigments and higher pigment concentrations in pigment compositions. However, as the particle size becomes finer and the concentration of the pigment increases, aggregation tends to occur, making it difficult to obtain a stable dispersion.

In order to solve these problems, improvement studies of the pigment itself (pigment surface treatment), development of dispersants and surfactants having good adsorptivity to pigments, and proposals of pigment derivatives and the like have been made so far. I came. A pigment derivative is a compound in which a substituent such as acidity or basicity is introduced into a pigment having the same structure or a structure similar to that of a pigment to be atomized, and has affinity and adsorptivity with the pigment and acid-base interaction. Because it has a strong binding force with the dispersant, it has the property of improving the fine particle formation and dispersion stabilization of the pigment, and is used in the pigment pulverization / dispersion fine particle formation step and the like. Pigments used in color filters and inkjets include phthalocyanine pigments, diketopyrrolopyrrole pigments, anthracinone pigments, quinacridone pigments, dioxazine pigments, isoindolin pigments, isoindolinone pigments, and azo pigments. Dye lake pigments and the like have been mentioned, and a number of pigment derivatives have been reported, especially phthalocyanine pigments, anthracinone pigments and quinacridone pigments. For example, a method of mixing a sulfonate of a pigment or a metal salt thereof with a pigment (Patent Documents 1 to 3), a method of mixing a substituted aminomethyl derivative (Patent Document 4), a method of mixing a phthalimide methyl derivative (Patent Document 5), and the like. It has been known.

Although these methods are effective for pigments having a specific skeleton, the number of substituents to be introduced and the number of substituents to be introduced for pigments for which it is structurally difficult to introduce sulfone groups, aminomethyl groups, phthalimidemethyl groups, etc. It is difficult to control the position, and as a result, the effect as a dispersant is insufficient, and a large amount of by-products that adversely affect the color tone are generated, and the quality of the pigment dispersion is not stable.
Further, in a pigment composition using Pigment Red 254, which has been widely used as a pigment for red in a color filter, improvement in transmittance has been an issue.

Tokukousho 41-2466 Japanese Unexamined Patent Publication No. 63-172772 Tokukousho 50-4019 Gazette Special Publication No. 39-16787 Japanese Unexamined Patent Publication No. 55-108466 U.S. Pat. No. 4,479,795

The problem to be solved by the present invention is C.I. I. By making a pigment composition (pigment dispersion) containing organic pigments such as red pigments such as Pigment Red 254 into fine particles and increasing the concentration of the pigment without causing aggregation, precipitation, and increase in viscosity over time. An object of the present invention is to provide a stable composition (dispersion) as a colorant for a color filter resist or an ink for inkjet.

As a result of diligent studies to solve the above problems, the present inventor has found that the above problems can be solved by using a compound composed of a benzoazole derivative, and has completed the present invention.
That is, the present invention
(1) The following formula (1)

(In the formula (1), R _{1 to} R ₈ represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a -CO ₂ M group or a -SO ₃ M group. . M represents a hydrogen atom, an alkali metal atom, an alkaline earth metal atom or -NZ ₁ Z ₂ Z ₃ Z ₄ groups. Z _{1 to} Z ₄ are hydrogen atoms, an alkyl group having 1 to 4 carbon atoms, and 1 carbon atom. Represents a hydroxyalkyl group of 4 to 4, an alkoxy group, a cycloalkyl group having 5 or 6 carbon atoms, an aryl group, or an alkyl group having 1 to 4 carbon atoms substituted with a cycloalkyl group having 5 or 6 carbon atoms. X represents an oxygen atom, a sulfur atom or a divalent linking group −NR ₉ −. R ₉ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms). Those salts,
(2) At least one of _{R 1 to} R _{8 is a -CO 2} M group or a -SO ₃ M group, and M is a hydrogen atom, a sodium atom, a potassium atom, a cesium atom, a calcium atom, a barium atom or a rosin ammonium (2). Avieta-8,11,13-triene-18-ammonium) The benzoazole compound according to the previous item (1) or a salt thereof,
(3) The benzoazole compound according to the previous item (2) or a salt thereof, _{wherein R 1 to} R ₈ are hydrogen atoms or -SO _{3 M groups.}
(4) A pigment composition containing the benzoazole compound according to any one of (1) to (3) above or a salt thereof, an organic pigment and a resin dispersant.
(5) The pigment composition according to (4) above, wherein the resin dispersant is a cationic resin dispersant.
(6) The pigment composition according to (4) or (5) above, wherein the amount of the benzoazole compound or a salt thereof added to 100 parts by mass of the organic pigment is 1 to 50 parts by mass.
(7) The pigment composition according to any one of (4) to (6) above, wherein the organic pigment is a pigment having a diketopyrrolopyrrole skeleton.
(8) A color resist containing the pigment composition, binder resin and polymerizable compound according to any one of (4) to (7) above.
(9) An inkjet ink composition containing the benzoazole compound according to any one of (1) to (3) above or a salt thereof, and (10) further containing at least one or more organic solvents. The inkjet ink composition according to (9) above.
Regarding.

The benzoazole compound represented by the formula (1) of the present invention or a salt thereof is extremely easy to produce, and by using the compound, C.I. I. Pigment composition containing pigments such as Pigment Red 254 can be made into fine particles and have a high concentration without causing aggregation, precipitation, and increase in viscosity over time, and is a colorant for color filter resists and inkjet inks. As a result, a stable dispersion can be obtained.

The present invention will be described in detail below.
The benzoazole compound of the present invention or a salt thereof has a structure represented by the following formula (1).

The benzoazole compound of the present invention or a salt thereof can be suitably used as a colorant for a resist for a color filter or an ink for inkjet. Hereinafter, for convenience, the term "compound of the present invention" may be simply referred to as "the compound of the present invention" including "the benzoazole compound of the present invention or a salt thereof".

In the formula (1), R _{1 to} R ₈ represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a -CO ₂ M group or a -SO ₃ M group. M represents a hydrogen atom, an alkali metal atom, an alkaline earth metal atom or -NZ ₁ Z ₂ Z ₃ Z ₄ groups. Z _{1 to} Z ₄ are hydrogen atoms, alkyl groups having 1 to 4 carbon atoms, hydroxyalkyl groups having 1 to 4 carbon atoms, aralkyl groups, cycloalkyl groups having 5 or 6 carbon atoms, aryl groups, or 5 carbon atoms. Alternatively, it represents an alkyl group having 1 to 4 carbon atoms substituted with a cycloalkyl group having 6 carbon atoms. X is an oxygen atom, a sulfur atom or a divalent linking group -NR ₉ - represents a. R ₉ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
_{The alkyl group having 1 to 4 carbon atoms represented by R 1 to} R ₈ of the formula (1) may be either a straight chain or a branched chain, but is preferably a straight chain, and specific examples thereof include a methyl group. Examples thereof include an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a sec-butyl group and a tert-butyl group, and a methyl group or an ethyl group is preferable.
_{The alkoxy group having 1 to 4 carbon atoms represented by R 1 to} R _{8 in} the formula (1) may be either a straight chain or a branched chain, but is preferably a straight chain, and specific examples thereof include a methoxy group. Examples thereof include an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, a sec-butoxy group and a tert-butoxy group, and a methoxy group or an ethoxy group is preferable.
_{Specific examples of the halogen atom represented by R 1 to} R ₈ of the formula (1) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a bromine atom or a chlorine atom is preferable.

Specific examples of the alkali metal atom and alkaline earth metal atom represented by M in the formula (1) include lithium atom, sodium atom, potassium atom, rubidium atom, cesium atom, franchium atom, calcium atom, strontium atom, and barium atom. And a radium atom, preferably a lithium atom, a sodium atom, a potassium atom, a cesium atom, a calcium atom, a strontium atom or a barium atom, and more preferably a cesium atom, a calcium atom or a barium atom. It is more preferably an atom or a calcium atom, and particularly preferably a calcium atom.
When at least one of _{R 1 to} R _{8 represents -CO 2} M group or -SO ₃ M group and M is an alkaline earth metal, it is referred to as the -CO ₂ M group or the -SO ₃ M group. One of the positive charges not involved in the binding may be bonded to any substance or compound having a negative charge, and all of them are benzoazole compounds having a structure represented by the formula (1) of the present invention. Or it is included in the category of those salts.

As a specific example of the alkyl group having 1 to 4 carbon atoms represented by _{Z 1 to} Z ₄ in the formula (1), a specific example of the alkyl group having 1 to 4 carbon atoms represented by _{R 1 to} R _{8 in the formula (1).} The same is mentioned, and the preferred one is also the same.
_{Specific examples of the hydroxyalkyl groups represented by Z 1 to} Z ₄ in the formula (1) include a hydroxymethyl group, a hydroxyethyl group, a 3-hydroxypropyl group, a 2-hydroxypropyl group, a 4-hydroxybutyl group, and 3-. Examples thereof include a hydroxybutyl group and a 2-hydroxybutyl group, and a hydroxyethyl group is preferable.
_{Specific examples of the aralkyl group represented by Z 1 to} Z ₄ in the formula (1) include a benzyl group, a phenylethyl group, a phenylpropyl group and a phenylbutyl group, and a benzyl group is preferable.
_{Specific examples of the cycloalkyl group having 5 or 6 carbon atoms represented by Z 1 to} Z ₄ in the formula (1) include a cyclopentyl group and a cyclohexyl group, and a cyclohexyl group is preferable. The cycloalkyl group referred to here may be expanded with a saturated hydrocarbon ring and / or an unsaturated hydrocarbon ring, and the hydrogen atom on the ring of the cycloalkyl group and / or the hydrogen atom on the expanded ring is alkyl. It may be substituted with a substituent such as a group. _{Specific examples of -NZ 1} Z ₂ Z ₃ Z ₄ groups having a cycloalkyl group having 5 carbon atoms or 6 carbon atoms which are ring-added and have an alkyl group include rosin ammonium (avieta-8,11,13). −Triene-18-ammonium) is preferred.
_{Specific examples of the aryl group represented by Z 1 to} Z ₄ in the formula (1) include a phenyl group and a naphthyl group, and a phenyl group is preferable.

The alkyl group having 1 to 4 carbon atoms substituted by the cycloalkyl group having 5 or 6 carbon atoms represented by _{Z 1 to} Z ₄ in the formula (1) is a cycloalkyl group having 5 or 6 carbon atoms. An alkyl group having 1 to 4 carbon atoms as a substituent, that is, a cycloalkyl-substituted alkyl group, and a specific example of the cycloalkyl group having 5 or 6 carbon atoms in the cycloalkylalkyl group is the formula (1). Specific examples of cycloalkyl groups having 5 or 6 carbon atoms represented by Z _{1 to} Z _{4 in the} group can be mentioned, and specific examples of alkyl groups having 1 to 4 carbon atoms in the cycloalkyl group include those. , The same specific examples of alkyl groups having 1 to 4 carbon atoms represented by _{R 1 to} R ₈ in the formula (1) can be mentioned.

As M in the formula (1), a hydrogen atom, a barium atom, a calcium atom, a cesium atom or a rosin ammonium (avieta-8,11,13-triene-18-ammonium) is preferable, and a hydrogen atom or a calcium atom is more preferable.

In the formula (1), X represents an oxygen atom, a sulfur atom or a divalent linking group -NR ₉ - represents a. R ₉ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
Specific examples of the alkyl group having 1 to 4 carbon atoms represented by R ₉ in the formula (1) are the same as the specific examples of the alkyl group having 1 to 4 carbon atoms represented by _{R 1 to} R _{8 in the formula (1).} The same is true for the preferred ones.
X in the formula (1) is an oxygen atom, a sulfur atom or a divalent linking group −NR ₉ −, and R ₉ is preferably a hydrogen atom or a methyl group, preferably a sulfur atom or a divalent linking group −. It is more preferable that NR ₉ − and R _{9 is a hydrogen atom.}

Examples of the benzoazole compound represented by the formula (1) of the present invention or a salt thereof include the above-mentioned R _{1 to} R ₈ (and -CO ₂ M group, -SO ₃ M group and -NZ ₁ Z ₂ Z ₃ Z. _{Of the four} groups, M, Z _{1 to} Z ₄ ) compounds in which preferable ones are combined or salts thereof are more preferable, and compounds in which more preferable ones are combined or salts thereof are further preferable.

Examples of the amine used when salt-forming the compound of the formula (1) include ammonia, diethylamine, triethanolamine, benzylamine, rosinamine (18-aminoavieta-8,11,13-triene) and the like.

The salt of the benzoazole compound represented by the formula (1) may be a free acid, a tautomer thereof, or a mixture of various salts thereof. Any combination may be used, for example, a mixture of cesium salt and ammonium salt, a mixture of free acid cesium salt, a mixture of lithium salt, calcium salt and cesium salt. Physical properties such as solubility may differ depending on the type of salt, and the physical properties suitable for the purpose can be selected by appropriately selecting the type of salt as necessary, or by changing the ratio when multiple salts are contained. It is also possible to obtain a mixture having.

The benzoazole compound of the present invention represented by the formula (1) can be synthesized by, for example, the following method.
That is, a desired compound can be obtained by subjecting a compound represented by the following formula (2) to a condensation reaction with a compound represented by the following formula (3). In the following formulas (2) and (3), R _{1 to} R ₈ and X have the same meanings as in the above formula (1).

Specific examples of the compound of the present invention are shown below. The acidic functional group of the compound is represented in the form of a free acid for convenience.

The pigment composition of the present invention contains the compound of the present invention, an organic pigment and a resin dispersant.
The organic pigment contained in the pigment composition of the present invention is not particularly limited as long as it is conventionally known, such as those described in the color index, but the compound itself represented by the formula (1) of the present invention is red. Since it has a hue, it is preferable to use a red-based organic pigment in the sense that the original hue of the organic pigment is not impaired, and it is more preferable to use an organic pigment classified as pigment red by the color index. I. Pigment Red 254 is even more preferred. Further, the organic pigment contained in the pigment composition is preferably an organic pigment having a diketopyrrolopyrrole skeleton in the sense that it is excellent in dispersion stability when mixed with the compound of the present invention.

The resin dispersant contained in the pigment composition of the present invention is not particularly limited as long as it is a known resin dispersant, but a cationic resin dispersant is preferable in consideration of affinity with the compound of the present invention. Examples of the cationic resin dispersant include BYK112, 116, 140, 142, 161, 162, 164, 166, 182, 2000, 2001, 2050, 2070, 2150 of Big Chemie Japan Co., Ltd., and EFKA4010 of Fuka Co., Ltd. Examples thereof include 4015, 4020, 4050, 4055, 4060, 4300, 4330, 4400, 4406, Solsperth of Nippon Lubrizol Co., Ltd., 24000, 32500, and Ajinomoto Fine Techno Co., Ltd. The amount of the resin dispersant added is usually 5 to 100 parts by mass, preferably 10 to 50 parts by mass with respect to 100 parts by mass of the organic pigment. When the amount of the resin dispersant added is less than 5 parts by mass, good dispersion stability cannot be obtained.

If necessary, an organic solvent can be added to the pigment composition of the present invention. The organic solvent that can be used is not particularly limited, and for example, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethyl cellosolve acetate, butyl cellosolve acetate, ethyl cellosolve, cyclohexanone, cyclopentanone, ethylene glycol diethyl ether, Examples thereof include diethylene glycol dimethyl ether, ethyl acetate, butyl acetate, methanol, ethanol and isopropyl alcohol. These may be used alone or in combination of two or more. The amount of the organic solvent used is 90% by mass or less in the pigment composition.

The color resist of the present invention contains the pigment composition, binder resin and polymerizable compound of the present invention.
The binder resin that can be used for the color resist of the present invention is not particularly limited, and for example, a styrene-based (co) polymer, a (meth) acrylic acid ester-based (co) polymer, a styrene-maleic acid ester-based copolymer, and cellulose. Examples thereof include acetate-based resins, polyester-based resins, polyurethane-based resins, polyamide-based resins, and polyimide-based resins. These may be used alone or in combination of two or more. The amount of the binder resin used is 50% by mass or less in the pigment composition.

Examples of the polymerizable compound that can be used in the color filter resist of the present invention include photopolymerizable monomers, epoxy compounds, and melamine compounds. Specific examples of these polymerizable compounds include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ethylene glycol di (meth) acrylate, and diethylene glycol di (meth). Acrylate, Triethylene Glyco (Meta) Acrylate, Tetraethylene Glycol (Meta) Acrylate, Trimethylol Propantri (Meta) Acrylate, Pentaerythritol Di (Meta) Acrylate, Pentaerythritol Tri (Meta) Acrylate, Pentaerythritol Tetra (Meta) Acrylate , Dipentaerythritol hexa (meth) acrylate, glycerol (meth) acrylate, bisphenol-A type epoxy di (meth) acrylate, bisphenol-F type epoxy di (meth) acrylate, bisphenol-fluorene type epoxy di (meth) acrylate, trimethyl ethoxylated Propanetri (meth) acrylate, propoxylated trimetyl propanetri (meth) acrylate, ethoxylated glycerin tri (meth) acrylate, ethoxylated isocyanurate tri (meth) acrylate, ditrimethylol propanetetra (meth) acrylate, ethoxylated pentaerythritol Tetra (meth) acrylate, 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene, Kayarad RP-1040 (manufactured by Nippon Kayaku), Kayarad DPCA-30 (manufactured by Nihon Kayaku), UA-33H (Meta) acrylate monomers such as (Shin-Nakamura Chemical), UA-53H (Shin-Nakamura Chemical) and M-8060 (Toa Synthetic); TEMPIC (Sakai Chemical), TMMP (Sakai Chemical), PEMP (Sakai) Thiol-based polymerized monomers such as (manufactured by Chemical) and DPMP (manufactured by Sakai Chemical); NC-6000, NC-6300, NC-6300H, NC-3000, EOCN-1020, XD-1000, EPPN-501H, Nippon Kayaku products. BREN-S, NC-7300L, Celokisite 2021P, EHPE3150, Cyclomer M100, Epolide PB3600, Japan Epoxy Resin Products Epicoat 828, Epicoat YX8000, Epicoat YX4000, Printec Products VG-3101L, Cyra Ace S510 (Chisso) ), TEPIC (Nissan Chemical Industry), etc.; and methylolated melamine And melamine compounds such as Mw-30 (Sanwa Chemical), but are not limited thereto.
It is preferable to use a polymerization initiator, a curing accelerator, or the like in combination with these polymerizable compounds, if necessary.

Other additives that can be added to the pigment composition of the present invention as necessary include, for example, thixo-imparting agents, polymerization initiators and curing agents, curing accelerators, polymerization inhibitors, organic or inorganic fillers, coupling agents and the like. These may be selected depending on the specific purpose and application of the pigment composition, and are not limited to the above. In addition, the amount of the addition may be selected according to the specific purpose and application.

The pigment composition of the present invention can be prepared, for example, by the following method. That is, as a method for blending the organic pigment and the compound of the present invention, various conventionally known methods, for example, a method of simply mixing the respective dry powders and press cakes, and various dispersions of kneaders, bead mills, dissolvers, attritors, etc. Examples thereof include a method of mechanically mixing by a machine, a method of suspending an organic pigment in water or an organic solvent, adding and mixing the compound of the present invention into the suspension, and uniformly depositing on the surface of the organic pigment. Next, a resin dispersant and, if necessary, various organic solvents, binder resins, various additives, etc. are mixed with the obtained mixture of the organic pigment and the compound of the present invention, and a sand mill, an annual bead mill, an attritor, etc. By dispersing in, a desired pigment composition can be produced. Alternatively, for convenience, the organic pigment, the compound of the present invention, the resin dispersant and, if necessary, other components may be mixed and dispersed all at once. The amount of the compound of the present invention added to the pigment composition of the present invention is usually 0.1 to 70 parts by mass, preferably 0.5 to 60 parts by mass, more preferably 0.5 parts by mass with respect to 100 parts by mass of the organic pigment. It is 1 to 50 parts by mass. If the compounding ratio of the compound of the present invention is too small, the desired dispersion stability and fine particle formation of the organic pigment cannot be achieved, and if the compounding ratio is increased too much, the dispersion stability is lowered. Optimization is needed.

The use of the pigment composition of the present invention is not particularly limited, and various printing inks such as gravure printing inks, paints, dry or wet toners for electrophotographic photography, ink jet recording inks, resist colorants for color filters, and the like. Uses can be mentioned. In particular, the pigment composition of the present invention is useful as a resist colorant for a color filter and an ink for inkjet recording, which require fine particle formation and high stability of the pigment.

Hereinafter, the present invention will be specifically described with reference to Examples. In addition, "part" and "%" in the text are based on mass unless otherwise specified. The maximum absorption wavelength in the examples is a value measured by a spectrophotometer "UV-3150 manufactured by Shimadzu Corporation", and the acid value is a value measured by a measuring method based on JIS K-0070: 1992. The weight average molecular weight is a value calculated in terms of polystyrene based on the measurement result of gel permeation chromatography.

Example 1 (Synthesis of the compound represented by No. 1 of the above-mentioned specific example compound)
(Step 1)
To a reaction vessel, 10 parts of 2-methylbenzimidazole, 17 parts of phthalic anhydride, 14 parts of benzoic acid and 100 parts of sulfolane were added, reacted at 160 ° C. for 7 hours, cooled to 30 ° C., and the reaction solution was methanol 300. In addition to the part, "suspension 1" was obtained. After filtering the "suspension 1", 15 parts of the obtained "wet cake 1" was dried with a hot air dryer at 80 ° C. to obtain 12 parts of the compound represented by the following formula (4).

(Step 2)
45 parts of 30% fuming sulfuric acid at 10 ° C. or lower is added to 45 parts of sulfuric acid, and 7 parts of the compound represented by the formula (4) obtained in step 1 is slowly added at 5 to 10 ° C. and then 5 to 10 ° C. Was reacted for 1 hour. This reaction solution was added dropwise to 400 parts of ice for about 10 minutes, and the precipitated solid was filtered and separated to obtain 33 parts of "wet cake 2" containing the compound represented by the following formula (5).

(Step 3)
After suspending 33 parts of "wet cake 2" obtained in step 2 in 100 parts of water and adjusting the pH value to 9 to 10 with a 25% aqueous sodium hydroxide solution, 4.4 parts of calcium chloride was added at room temperature. Stirred for 1 hour. By drying 26 parts of "Wet Cake 3" obtained by filtering the suspension with a hot air dryer at 80 ° C., Specific Example Compound No. Twelve parts of the compound represented by 1 were obtained. The maximum absorption wavelength λmax of the compound was 352 nm (NMP).

Example 2 (Synthesis of the compound represented by No. 2 of the above-mentioned specific example compound)
(Step 4)
To a reaction vessel, 10 parts of 2-methylbenzothiazole, 35 parts of phthalic anhydride, 12 parts of benzoic acid and 100 parts of sulfolane were added, reacted at 180 ° C. for 5 hours, cooled to 30 ° C., and the reaction solution was methanol 300. In addition to the part, "suspension 2" was obtained. After filtering the "suspension 2", 2.7 parts of the obtained "wet cake 4" is dried in a hot air dryer at 80 ° C. to obtain 2.5 of the compound represented by the following formula (6). I got a part.

(Step 5)
20 parts of 30% fuming sulfuric acid at 10 ° C. or lower is added to 20 parts of sulfuric acid, and 2 parts of the compound represented by the formula (6) obtained in step 4 is slowly added at 5 to 10 ° C., and then 5 to 10 ° C. Was reacted for 1 hour. This reaction solution was added dropwise to 100 parts of ice for about 10 minutes, and the precipitated solid was filtered and separated to obtain 10 parts of "wet cake 5" containing the compound represented by the following formula (7).

(Step 6)
After suspending 10 parts of "wet cake 5" obtained in step 5 in 50 parts of water and adjusting the pH value to 9 to 10 with a 25% aqueous sodium hydroxide solution, add 2.0 parts of calcium chloride at room temperature. Stirred for 1 hour. By drying 26 parts of "Wet Cake 6" obtained by filtering the suspension with a hot air dryer at 80 ° C., Specific Example Compound No. 3.1 parts of the compound represented by 2 were obtained. The maximum absorption wavelength λmax of the compound was 374 nm (NMP).

Synthesis Example 1 (Adjustment of binder resin A)
160 parts of methyl ethyl ketone, 10 parts of methacrylic acid, 33 parts of benzyl methacrylate, and 1 part of α, α'-azobis (isobutyronitrile) are charged in a 500 ml four-necked flask, and nitrogen gas flows into the flask for 30 minutes with stirring. did. Then, the temperature was raised to 80 ° C., and the mixture was stirred as it was at 80 to 85 ° C. for 4 hours. After completion of the reaction, the mixture was cooled to room temperature to obtain a colorless, transparent and uniform binder resin solution. This was precipitated in a 1: 1 mixed solution of isopropyl alcohol and water, filtered, and the solid content was taken out and dried to obtain a binder resin A. The polystyrene-equivalent weight average molecular weight of the obtained binder resin A was 18,000, and the acid value was 152.

Example 3 (Preparation of Pigment Composition of the Present Invention)
As an organic pigment, C.I. I. Pigment Red 254 10.0 parts, No. 1 obtained in Example 1 as the compound of the present invention. 1.0 part of the compound shown in 1, 1.8 parts of the binder resin A obtained in Synthesis Example 1 as the binder resin, Azisper PB881 (manufactured by Ajinomoto Fine-Techno) as the resin dispersant, 82 parts of propylene glycol monomethyl ether acetate as the solvent. Was compounded, and after premixing, it was dispersed in a paint shaker for 60 minutes using 0.3 mm zirconia beads. The pigment composition was prepared by filtering the obtained dispersion liquid with a filter of 5 μm.

Example 4 (Preparation of Pigment Composition of the Present Invention)
No. obtained in Example 1. No. 1 obtained in Example 2 instead of the compound shown in 1. A pigment composition was prepared in the same manner as in Example 3 except that the compound shown in 2 was used.

Comparative Example 1 (Preparation of Pigment Composition for Comparison)
No. obtained in Example 1. A pigment composition was prepared in the same manner as in Example 3 except that the compound shown in 1 was not used.

The viscosity of the pigment compositions of Examples 3 and 4 and Comparative Example 1 was measured using a B-type viscometer at room temperature (25 ° C.) and 10 rpm, and evaluated according to the following criteria. In addition to the initial stage (immediately after adjustment), the viscosity after standing at 40 ° C. for 3 days was also measured and evaluated in order to confirm the storage stability. The results are shown in Table 1.
・ Evaluation criteria Initial viscosity: less than 20 mPa ・ s ○, 20 mPa ・ s or more ×
40 ° C x 3 days Viscosity increase rate: Less than 20% ○, 20% or more ×
The viscosity of the gelled product immediately after preparation after being left at 40 ° C. for 3 days was regarded as "unevaluable".

As is clear from Table 1, the pigment compositions of Examples 3 and 4 have lower initial viscosities than Comparative Example 1 to which the present pigment derivative is not added, and the workability and resist in actual use are suppressed. And does not impair the quality of the ink. Furthermore, the storage stability was also better than that of the comparative example.
Specifically, while Comparative Example 1 could not be dispersed due to gelation, Examples 3 and 4 had a viscosity increase rate of 20% or less after 40 ° C. × 3 days.

By using the benzoazole compound of the present invention, it is possible to make fine particles and increase the concentration without aggregation, sedimentation, and increase in viscosity with time, and the pigment derivative can be a color filter resist or an inkjet ink. As a colorant for, it is very useful for obtaining a stable dispersion.

Claims (8)

The following formula (1)

(In the formula (1), R _{1 to} R ₈ represent a hydrogen atom or -SO ₃ M group, where at least one of _{R 1 to} R _{8 represents a -SO 3} M group, where M represents a hydrogen atom or sodium. Represents an atom, a potassium atom, a cesium atom, a calcium atom, a barium atom or a rosin ammonium (avieta-8,11,13-triene-18-ammonium). X is an oxygen atom, a sulfur atom or a divalent linking group-NR _9. Represents −. R ₉ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.) A benzoazole compound having a structure represented by () or a salt thereof. A pigment composition containing the benzoazole compound according to claim 1 or a salt thereof, an organic pigment, and a resin dispersant. The pigment composition according to claim 2, wherein the resin dispersant is a cationic resin dispersant. The pigment composition according to claim 2 or 3, wherein the amount of the benzoazole compound or a salt thereof added to 100 parts by mass of the organic pigment is 1 to 50 parts by mass. The pigment composition according to any one of claims 2 to 4, wherein the organic pigment is a pigment having a diketopyrrolopyrrole skeleton. A color resist containing the pigment composition, binder resin and polymerizable compound according to any one of claims 2 to 5. An inkjet ink composition containing the benzoazole compound according to claim 1 or a salt thereof. The inkjet ink composition according to claim 7, further comprising at least one organic solvent.