Pigment dispersion liquid and coating agent

Abstract

To provide a pigment dispersion liquid that can easily suppress the aggregation of C.I. Pigment Orange 43, ensuring long-term storage stability.SOLUTION: A pigment dispersion liquid contains a liquid medium, C.I. Pigment Orange 43 and a dispersant. The dispersant includes at least one benzothiazole derivative selected from the group consisting of a compound represented by the general formula (1), and its metal salts, ammonium salts, organic amine salts, and salts of organic quaternary ammonium compounds. (In the general formula (1), R1 is an optionally substituted aryl group).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a pigment dispersion and a coating agent.

Background Art

[0002] Generally, when mixing and dispersing pigments in vehicles such as paints, gravure inks, offset inks, inks for writing instruments, and inkjet inks, it is difficult to stably disperse the pigments in the vehicle, and the dispersed fine pigment particles tend to aggregate in the vehicle. As a result, problems such as an increase in viscosity, a decrease in coloring power and gloss, etc. may occur.

[0003] In recent years, due to its simple and inexpensive characteristics in the inkjet image forming method, the development of commercial printing equipment and industrial printing equipment has been carried out. For example, so-called sign applications such as outdoor billboards fall into this category. In this case, high weather resistance and wide color reproducibility outdoors are required. To achieve these, in addition to inks of each color of yellow, magenta, cyan, and black, an ink set using an ink containing C.I. Pigment Orange 43 having relatively high weather resistance as a feature has been proposed (Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] Aggregation tendency in the vehicle has also been confirmed for C.I. Pigment Orange 43. Therefore, the dispersion containing C.I. Pigment Orange 43 has low storage stability, and when the dispersion is stored for a long period of time, thickening of the dispersion, generation of foreign substances, etc. are confirmed. These cause clogging of the nozzles that discharge coating agents such as inks containing the above dispersion, and induce problems such as nozzle detachment. As a solution to this, Patent Document 3 proposes containing a glycol ether having a flash point of 70°C or lower in the ink. According to the description in Patent Document 3, it is presumed that the above glycol ether can suppress the increase in moisture during long-term storage of the ink, and thus aggregation of C.I. Pigment Orange 43 is suppressed. However, with this method, it is necessary to dehydrate solvents, etc. in advance, and it is also necessary to pay attention to moisture absorption in the process of manufacturing the ink.

[0006] In view of the prior art as described above, the present invention aims to provide a pigment dispersion that can more simply suppress the aggregation of C.I. Pigment Orange 43 without going through a dehydration process and has good long-term storage stability.

Means for Solving the Problems

[0007] According to the present invention, there is provided a pigment dispersion containing a liquid medium, C.I. Pigment Orange 43, and a dispersant, wherein the dispersant contains at least one selected from the group consisting of a benzothiazole derivative represented by the following general formula (1), and its metal salts, ammonium salts, organic amine salts, and salts of organic quaternary ammonium compounds.

[0008] TIFF0007691953000001.tif43170(In the general formula (1), R 1 represents an aryl group which may have a substituent.)

Effects of the Invention

[0009] According to the present invention, it is possible to suppress the aggregation of C.I. Pigment Orange 43, and a pigment dispersion having good long-term storage stability can be provided.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0011] <Pigment Dispersion Liquid> The pigment dispersion liquid of one embodiment of the present invention contains a liquid medium, C.I. Pigment Orange 43, and a dispersant. The dispersant contained in the pigment dispersion liquid includes at least one benzothiazole derivative selected from the group consisting of a compound represented by the following general formula (1), and its metal salts, ammonium salts, organic amine salts, and salts of organic quaternary ammonium compounds.

[0012] TIFF0007691953000002.tif43170 (R in the general formula (1) 1 represents an aryl group which may have a substituent.)

[0013] Since the pigment dispersion liquid of the present embodiment contains a specific benzothiazole derivative, it is possible to suppress the aggregation of C.I. Pigment Orange 43 and has good storage stability over a long period. From the viewpoint of obtaining these effects, the preferred configuration and the like of the pigment dispersion liquid will be described below.

[0014] (C.I. Pigment Orange 43) The pigment dispersion liquid of the present embodiment contains C.I. Pigment Orange 43 (hereinafter, may be referred to as "PO43"). In the pigment dispersion liquid, PO43 can be in a form dispersed in the liquid medium by a dispersant described later.

[0015] PO43 is a pigment with a CAS registration number of 4424-06-0. The chemical name of PO43 is bisbenzimidazo[2,1-b:2’,1’-i]benzol[lmn][3,8]phenanthroline-8,17-dione, or 1,8-(1H-benzimidazole-2,1-diylcarbonyl)-5,4-(1H-benzimidazole-2,1-diylcarbonyl)naphthalene. C.I. Pigment Orange 43 has a perylene structure and has a vivid orange hue with a red tint.

[0016] The volume average particle diameter of C.I. Pigment Orange 43 contained in the pigment dispersion is preferably 80 nm or more and 400 nm or less, more preferably 90 nm or more and 350 nm or less, and even more preferably 100 nm or more and 300 nm or less. Even when PO43s with different volume average particle diameters are mixed and used, the volume average particle diameter of each PO43 is preferably within the above range. When the volume average particle diameter of PO43 is within the above range, the dispersion stability is good, and when the pigment dispersion is contained in a coating agent such as ink, the ejection property and the weather resistance of the coating film are more likely to be good. From the viewpoint of storage stability, the volume average particle diameter of PO43 is preferably 80 nm or more, more preferably 90 nm or more, and even more preferably 100 nm or more. On the other hand, from the viewpoint of suppressing nozzle clogging, etc., that is, from the viewpoint of ejection property, the volume average particle diameter of PO43 is preferably 400 nm or less, more preferably 350 nm or less, and even more preferably 300 nm or less.

[0017] In this specification, the volume average particle diameter of PO43 means the particle diameter (median diameter; D 50 ) that becomes 50% cumulative in the volume-based particle size distribution measured by the dynamic light scattering method. For the measurement of the volume average particle diameter of PO43, a particle size distribution measuring device using the dynamic light scattering method (for example, the product name “FPAR-1000” manufactured by Otsuka Electronics Co., Ltd.) can be used.

[0018] The content of C.I. Pigment Orange 43 in the pigment dispersion is preferably 1% by mass or more and 90% by mass or less based on the total mass of the pigment dispersion. When the content of PO43 is within the above range, sufficient color development property is easily obtained, and the dispersion stability is likely to be enhanced. From the viewpoint of color development property, the above content of PO43 is preferably 1% by mass or more, more preferably 5% by mass or more, further preferably 10% by mass or more, and even more preferably 15% by mass or more. On the other hand, from the viewpoint of dispersion stability, the above content of PO43 is preferably 90% by mass or less, more preferably 70% by mass or less, further preferably 50% by mass or less, and even more preferably 30% by mass or less.

[0019] The pigment dispersion may contain a colorant such as a pigment other than PO43, but the ratio of PO43 to the total mass of the colorant is preferably 50% by mass or more, more preferably 70% by mass or more, and further preferably 90% by mass or more. Thus, it is preferable to use PO43 as the main component of the colorant and use the pigment dispersion as an orange pigment dispersion.

[0020] (Benzothiazole derivative) The pigment dispersion of the present embodiment contains at least one benzothiazole derivative (hereinafter, may be simply referred to as "benzothiazole derivative") selected from the group consisting of a compound represented by the following general formula (1), and its metal salts, ammonium salts, organic amine salts, and salts of organic quaternary ammonium compounds (hereinafter, various salts may be collectively simply referred to as "salts"). In the pigment dispersion, the benzothiazole derivative has a role as a dispersant for dispersing C.I. Pigment Orange 43 in the liquid medium.

[0021] TIFF0007691953000003.tif43170

[0022] R in the general formula (1) 1represents an aryl group which may have a substituent. Examples of the aryl group include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, and a biphenylyl group, etc. Among these, a phenyl group is preferred.

[0023] Examples of the substituent include halogen atoms such as a fluorine atom, a chlorine atom, and a bromine atom, alkyl groups such as a methyl group, an ethyl group, and a propyl group, alkoxy groups such as a methoxy group, an ethoxy group, and a propoxy group, and a hydroxy group, an amino group, a nitro group, a carbamoyl group, a sulfamoyl group, a carboxylic acid group, a sulfonic acid group, and a phosphonic acid group, etc. The number of substituents may be one or two or more. Among the substituents, a halogen atom and an alkyl group are preferred. Also, R in the general formula (1) 1 more preferably represents an unsubstituted phenyl group or a phenyl group substituted with a halogen atom or an alkyl group.

[0024] Examples of the compound (benzothiazole derivative) represented by the general formula (1) include compounds having a structure represented by the following structural formula as a structure bonded to the azo group (N=N) in the general formula (1). In the following structural formula, * represents the bonding site with the azo group in the general formula (1).

[0025] TIFF0007691953000004.tif138170

[0026] As a result of the intensive studies by the present inventors, among the compounds represented by the general formula (1), the compounds (benzothiazole derivatives) represented by the following chemical formulas (1-1), (1-2), and (1-3) were found to be more effective in the dispersion stabilization of C.I. Pigment Orange 43. Therefore, the pigment dispersion preferably contains at least one selected from the group consisting of the compounds represented by the following chemical formulas (1-1) to (1-3) and their salts.

[0027] TIFF0007691953000005.tif45170

[0028] TIFF0007691953000006.tif51170

[0029] TIFF0007691953000007.tif50169

[0030] The benzothiazole derivative may be a metal salt, ammonium salt, organic amine salt, or salt of an organic quaternary ammonium compound of the compound represented by the above general formula (1). Examples of the metal constituting the metal salt include alkali metals such as lithium, sodium, and potassium. Examples of the organic amine constituting the organic amine salt include trimethylamine, triethylamine, dimethylaminoethanol, and triethanolamine. Examples of the quaternary ammonium constituting the salt of the organic quaternary ammonium compound include tetramethylammonium and tetraethylammonium.

[0031] The compound (benzothiazole derivative) represented by the general formula (1) can be obtained by subjecting a diazonium compound (diazonium salt) obtained by diazotizing 2-(4-aminophenyl)-6-methylbenzothiazole-7-sulfonic acid by a conventional method to a coupling reaction with a compound represented by the following general formula (A). Further, for example, when isolating and purifying the obtained compound represented by the general formula (1), salts of the compound represented by the general formula (1) can also be obtained by a salting-out method using the salts constituting the above-mentioned salts.

[0032] TIFF0007691953000008.tif36170 (R in the general formula (A) 1 is synonymous with R in the general formula (1).) 1

[0033] ​The content of the benzothiazole derivative in the pigment dispersion is preferably 0.05% by mass or more and 40% by mass or less with respect to the content of C.I. Pigment Orange 43 in the pigment dispersion. When the content of the benzothiazole derivative with respect to the content of PO43 is within the above range, it is easy to obtain a pigment dispersion having good weather resistance and even better storage stability. From these viewpoints, the content of the benzothiazole derivative with respect to the content of PO43 is more preferably 0.1% by mass or more and 30% by mass or less, even more preferably 0.5% by mass or more and 20% by mass or less, and still more preferably 1% by mass or more and 10% by mass or less. The content of the benzothiazole derivative with respect to the content of PO43 can be determined from the content P of PO43 and the content B of the benzothiazole derivative in the pigment dispersion by [B / P]×100 (mass%).

[0034] If the content of the benzothiazole derivative with respect to the content of PO43 is within the above range, the content of the benzothiazole derivative with respect to the total mass of the pigment dispersion is not particularly limited. The content of the benzothiazole derivative is preferably 0.0005% by mass or more and 36% by mass or less with respect to the total mass of the pigment dispersion. The content of the benzothiazole derivative with respect to the total mass of the pigment dispersion is more preferably 0.0025% by mass or more, even more preferably 0.005% by mass or more, and still more preferably 0.0075% by mass or more. On the other hand, the content of the benzothiazole derivative with respect to the total mass of the pigment dispersion is more preferably 28% by mass or less, even more preferably 20% by mass or less, and still more preferably 12% by mass or less.

[0035] (Liquid medium) The pigment dispersion of this embodiment contains a liquid medium. In the pigment dispersion, the liquid medium serves as a dispersion medium for C.I. Pigment Orange 43. As the liquid medium, those in a liquid form at normal temperature (20°C ± 15°C) can be used.

[0036] The liquid medium is not particularly limited, and an appropriate liquid medium can be selected and used according to the application for which the pigment dispersion is used. For example, when the pigment dispersion is used as a colorant for gravure ink, a colorant for paint, a colorant for color filter, etc. in a solvent-based ink (oil-based ink), an organic solvent can be preferably used as the liquid medium. Further, when the pigment dispersion is used as a colorant for an active energy ray curable inkjet ink, etc. in an active energy ray curable ink such as an ultraviolet curable ink and an electron beam curable ink, a polymerizable compound can be preferably used as the liquid medium. The liquid medium preferably contains at least one selected from the group consisting of an organic solvent and a polymerizable compound. By using the liquid medium as an organic solvent and / or a polymerizable compound, an oil-based pigment dispersion that is non-aqueous can be obtained.

[0037] As the organic solvent, for example, those conventionally used in oil-based inks can be used. Examples of the organic solvent include ketone solvents, hydrocarbon solvents, ester solvents, ether solvents, glycol ether solvents, and alcohol solvents, etc., and one of them can be used alone or two or more of them can be used in combination.

[0038] Examples of the ketone solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl cyclohexanone, and diacetone alcohol. Examples of the hydrocarbon solvents include aromatic hydrocarbon solvents such as toluene and xylene; aliphatic hydrocarbon solvents such as n-hexane, n-heptane, and n-octane; and alicyclic hydrocarbon solvents such as cyclopentane, cyclohexane, methyl cyclohexane, dimethyl cyclohexane, and cyclooctane. Examples of the ester solvents include methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, and isobutyl acetate. Examples of the ether solvents include tetrahydrofuran, dioxane, diethyl ether, and methyl ethyl ether. Examples of the glycol ether solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and propylene glycol monomethyl ether. Examples of the alcohol solvents include monohydric alcohols such as methanol, ethanol, n-propanol, isopropanol, and n-butanol; and polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin.

[0039] As the polymerizable compound, for example, those conventionally used in the active energy ray-curable ink can be used. Examples of the polymerizable compound include monofunctional monomers, polyfunctional monomers, photocurable oligomers, and photocurable polymers, and one of them can be used alone or in combination of two or more. In the present specification, the phrase “(meth)acryl” means that both the phrases “acryl” and “methacryl” are included. Similarly, the phrase “(meth)acrylate” means that both the phrases “acrylate” and “methacrylate” are included.

[0040] Examples of monofunctional monomers include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, adamantyl (meth)acrylate, adamantylmethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polyethylene glycol monomethyl ether (meth)acrylate, 2-ethoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, allyl (meth)acrylate, vinyloxyethoxyethyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, an adduct of phthalic anhydride and 2-hydroxyethyl (meth)acrylate, acryloylmorpholine, and N-vinylcaprolactam, etc.

[0041] Examples of the polyfunctional monomer and the photocurable oligomer include neopentyl glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, poly(n≥2)ethylene glycol di(meth)acrylate, polypropylene glycol (n≥2) di(meth)acrylate, polybutylene glycol (n≥2) di(meth)acrylate, 2,2-bis(4-(meth)acryloxyethoxyphenyl)propane, 2,2-bis(4-(meth)acryloxydiethoxyphenyl)propane, trimethylolpropane diacrylate, bis(2-(meth)acryloxyethyl)-hydroxyethyl-isocyanurate, trimethylolpropane tri(meth)acrylate, tris(2-(meth)acryloxyethyl) isocyanurate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy poly(meth)acrylate such as epoxy di(meth)acrylate obtained by reacting bisphenol A type diepoxy with (meth)acrylic acid, 1,Urethane tri(meth)acrylate obtained by reacting a trimer of 6-hexamethylene diisocyanate with 2-hydroxyethyl (meth)acrylate, urethane di(meth)acrylate obtained by reacting isophorone diisocyanate with 2-hydroxypropyl (meth)acrylate, urethane hexa(meth)acrylate obtained by reacting isophorone diisocyanate with pentaerythritol tri(meth)acrylate, urethane di(meth)acrylate obtained by reacting dicyclohexyl diisocyanate with 2-hydroxyethyl (meth)acrylate, urethane poly(meth)acrylate such as urethane di(meth)acrylate obtained by reacting a urethanization reaction product of dicyclohexyl diisocyanate and poly(n = 6 to 15) tetramethylene glycol with 2-hydroxyethyl (meth)acrylate, polyester poly(meth)acrylate such as polyester (meth)acrylate obtained by reacting trimethylolethane with succinic acid and (meth)acrylic acid, polyester (meth)acrylate obtained by reacting trimethylolpropane with succinic acid, ethylene glycol, and (meth)acrylic acid, etc. can be mentioned.,

[0042] Examples of the photocurable polymer include polymers in which a plurality of (meth)acryloyloxy groups exhibiting radical polymerizability are introduced at the terminals or side chains of polymers such as poly(meth)acrylate, polyurethane, polyester, polyamide, polyimide, and epoxy resin. Furthermore, an alkali-developable photocurable polymer having a carboxy group or the like can also be used.,

[0043] The content of the liquid medium in the pigment dispersion is preferably 9% by mass or more and 98% by mass or less with respect to the total mass of the pigment dispersion. The above content of the liquid medium is more preferably 29% by mass or more, and even more preferably 49% by mass or more. Also, the above content of the liquid medium is more preferably 94% by mass or less, and even more preferably 89% by mass or less.,

[0044] (Other components) In addition to PO43, benzothiazole derivatives, and a liquid medium, the pigment dispersion may contain other components. Examples of other components include colorants other than PO43, dispersants other than benzothiazole derivatives (e.g., polyurethane resins, acrylic resins, styrene-acrylic acid copolymers, polyester polyamide resins, etc.), surfactants, light stabilizers, ultraviolet absorbers, leveling agents, and defoaming agents, etc. One or more of these can be used.

[0045] (Method for producing a pigment dispersion) The method for producing the pigment dispersion is not particularly limited, and the pigment dispersion can be produced by mixing and dispersing C.I. Pigment Orange 43, benzothiazole derivatives, a liquid medium, and, if necessary, other components.

[0046] From the viewpoint of enhancing dispersion stability, it is preferable to adsorb a dispersant containing a benzothiazole derivative onto C.I. Pigment Orange 43. Examples of the adsorption method include methods carried out during the refinement of the pigment (PO43) such as a salt milling process or a dry grinding process, a method of mixing the respective powders, a method of mixing slurries, or a method carried out during the dispersion process of pigments etc. using a dispersant. Among these, in order to perform a uniform adsorption treatment of the dispersant containing a benzothiazole derivative on the particle surface of the pigment (PO43), it is preferably carried out during the dispersion process.

[0047] When producing the pigment dispersion, it is preferable to mix and stir a dispersant containing a benzothiazole derivative, PO43, and a liquid medium, and, if necessary, other components, and use a disperser to disperse PO43.

[0048] Examples of the disperser include kneaders such as a kneader, two-roll mill, three-roll mill, SS5 (trade name, M-Technique Co., Ltd.), Miracle KCK (trade name, Asada Steel Co., Ltd.), ultrasonic dispersers, high-pressure homogenizers, Microfluidizer (trade name, Mizuhobankogyo Co., Ltd.), Nanomizer (trade name, Yoshida Kikai Kogyo Co., Ltd.), Starburst (trade name, Sugino Machine Ltd.), G-Smasher (trade name, Rix Co., Ltd.), paint shaker, ball mill, attritor, and sand mill. Also, for those using bead media such as glass, zircon, and zirconia, a paint shaker, ball mill, attritor, sand mill, horizontal media mill disperser, and colloid mill can be used. As the bead media, for example, bead media with a diameter of about 0.5 mm or more and 1 mm or less is preferably used. In the dispersion of the colorant for the color filter, it is preferable to perform dispersion twice by changing the bead diameter, and in the second dispersion, by using beads with a diameter smaller than the diameter of the beads used in the first dispersion, the pigment (PO43) can be made finer. Further, the obtained pigment dispersion may be used as it is, but it is preferable to remove any coarse particles that may be present using a centrifuge, ultracentrifuge, or filter.

[0049] Since the pigment dispersion of the present embodiment described in detail above contains a liquid medium, PO43, and the aforementioned specific benzothiazole derivative, it is possible to more easily suppress the aggregation of C.I. Pigment Orange 43 and has good long-term storage stability. Therefore, by using this pigment dispersion, it is possible to provide a coating agent that has good long-term storage stability and is difficult for PO43 to aggregate. Therefore, the pigment dispersion can be suitably used as a colorant for an active energy ray-curable inkjet ink, a colorant for gravure ink, or a colorant for paint. Further, since the pigment dispersion of the present embodiment has good weather resistance, it is suitable for outdoor applications such as sign displays and as a colorant for color filters. Next, the coating agent will be described.

[0050] <Coating agent> The coating agent of one embodiment of the present invention contains the aforementioned pigment dispersion. Since the pigment dispersion is preferably an oil-based pigment dispersion that is non-aqueous as described above, an oil-based coating agent that is non-aqueous is also preferred for the coating agent.

[0051] A coating agent is an agent that adheres to the surface of an article or the like and exhibits the action of covering at least a part of the surface of the article or the like. Therefore, the coating agent can be applied to various applications that exhibit such an action. Specifically, paints, stationery, electronic materials, gravure inks, offset inks, inkjet inks, active energy ray curable inks, color filters, toners, cosmetics, resist printing, adhesives, pressure-sensitive adhesives, photoresist materials, and medical materials, etc. can be mentioned. Among these, the coating agent is preferably a paint, gravure ink, inkjet ink, or active energy ray curable ink, and more preferably a gravure ink or an active energy ray curable inkjet ink.

[0052] The content of C.I. Pigment Orange 43 in the coating agent is preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.5% by mass or more and 15% by mass or less, and even more preferably 1% by mass or more and 10% by mass or less, based on the total mass of the coating agent.

[0053] In addition to the aforementioned pigment dispersion, the coating agent can contain the organic solvent and polymerizable compound described in the description of the liquid medium contained in the pigment dispersion, the other components described in the description of the pigment dispersion, and other additives, etc. By mixing these optional components with the aforementioned pigment dispersion, a coating agent can be obtained. Examples of other additives include binder resins, photopolymerization initiators, photopolymerization inhibitors, slip agents, and antioxidants, etc. These may be added during dispersion when preparing the pigment dispersion, but it is preferable to add them during the ink formation process.

[0054] The coating agent of this embodiment can be applied to a base material which is various articles, and a coating film can be formed by drying and / or reacting the coating agent. The method of applying the coating agent is not particularly limited. For example, the coating agent can be applied to the base material by a spin coating method, a gravure coating method, an inkjet method, a screen printing method, a bar coating method, a doctor blade method, a roll coating method, a dip method, a spray method, a flexographic printing method, a reverse roll coater method, etc.

[0055] The base material to which the coating agent is applied is not particularly limited, and examples thereof include base materials used in the fields of optical materials, electrical materials, building materials, recording materials, display materials, and medical materials. The coating agent can be preferably used as a surface coating agent or a surface treatment agent for articles in those fields. The material of the base material is not particularly limited, and examples thereof include metals such as stainless steel and copper, glass, ceramics, inorganic oxides, silicon, wood, paper, plastic materials, and the like.

[0056] As described above, in this embodiment, the following configurations can be adopted. [1] A pigment dispersion liquid containing a liquid medium, C.I. Pigment Orange 43, and a dispersant, wherein the dispersant contains at least one benzothiazole derivative selected from the group consisting of a compound represented by the above general formula (1), and its metal salts, ammonium salts, organic amine salts, and salts of organic quaternary ammonium compounds. [2] The pigment dispersion liquid according to the above [1], wherein the content of C.I. Pigment Orange 43 in the pigment dispersion liquid is 1% by mass or more and 90% by mass or less based on the total mass of the pigment dispersion liquid. [3] The pigment dispersion liquid according to the above [1] or [2], wherein the content of the benzothiazole derivative in the pigment dispersion liquid is 0.05% by mass or more and 40% by mass or less based on the content of C.I. Pigment Orange 43 in the pigment dispersion liquid. [4] The pigment dispersion liquid according to any one of the above [1] to [3], wherein the liquid medium contains at least one selected from the group consisting of an organic solvent and a polymerizable compound. [5] The pigment dispersion according to any one of [1] to [4] above, which is a colorant for active energy ray curable inkjet ink, a colorant for gravure ink, a colorant for paint, or a colorant for color filter. [6] A coating agent containing the pigment dispersion according to any one of [1] to [5] above.

Examples

[0057] Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. In addition, "parts" and "%" in the examples and comparative examples are based on mass unless otherwise specified.

[0058] <Preparation of materials> The following pigments, dispersants, polymerizable compounds, photoinitiators, photopolymerization inhibitors, and slip agents were prepared.

[0059] (Pigment) · C.I. Pigment Orange 43 (trade name "PV Gast Orange GRL", manufactured by Clariant; hereinafter may be referred to as "PO43").

[0060] (Dispersant) · Solsperse 37500 (trade name of Lubrizol; polyester polyamide resin)

[0061] (Polymerizable compound〉 · 2-(2-Vinyloxyethoxy)ethyl acrylate (manufactured by Nippon Shokubai; hereinafter may be referred to as "VEEA"). · Isobornyl acrylate (manufactured by Osaka Organic Chemical Industry; hereinafter may be referred to as "IBXA"). · N-Vinylcaprolactam (manufactured by ISP Japan; hereinafter may be referred to as "V-CAP"). · Phenoxyethyl acrylate (trade name "SR339A" of Sartomer; hereinafter may be referred to as "PEA").

[0062] (Photoinitiator) ·IRGACURE 819 (trade name of bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide manufactured by BASF) ·DAROCURE TPO (trade name of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide manufactured by BASF)

[0063] (Photopolymerization inhibitor) ·p-Methoxyphenol (manufactured by Kanto Chemical Co., Inc.)

[0064] (Slip agent) ·BYK-UV3500 (trade name of BYK; polydimethylsiloxane having a polyether-modified acrylic group)

[0065] (Production of benzothiazole derivatives) Benzothiazole derivatives (1-1) to (1-3) were produced according to the following procedure. For the measurement of molecular weight and the identification of structure, a matrix-assisted laser desorption ionization time-of-flight mass spectrometer (MALDI-TOF MS (hereinafter simply referred to as "MALDI"; trade name "autoflex maX", manufactured by BRUKER)) was used.

[0066] (Synthesis Example 1) Production of benzothiazole derivative (1-1) 9.61 parts of 2-(4-aminophenyl)-6-methylbenzothiazole-7-sulfonic acid was diazotized by a conventional method to obtain a solution of a diazonium salt. On the other hand, 5.23 parts of 3-methyl-1-phenyl-2-pyrazolin-5-one and 4.8 parts of sodium hydroxide were dissolved in 450 parts of water to prepare a solution. The solution of the above diazonium salt was added to this solution, and a coupling reaction was carried out at room temperature for 3 hours. After filtration and washing with water, it was dried to obtain 11.7 parts of the benzothiazole derivative (1-1) represented by the above chemical formula (1-1). When mass spectrometry was performed by MALDI, a peak with a molecular weight of 506 was detected.

[0067] (Synthesis Example 2) Production of benzothiazole derivative (1-2) Instead of 5.23 parts of 3-methyl-1-phenyl-2-pyrazolin-5-one used in Synthesis Example 1, 5.65 parts of 3-methyl-1-p-tolyl-2-pyrazolin-5-one was used for synthesis. Otherwise, in the same manner as in Synthesis Example 1, 12.3 parts of the benzothiazole derivative (1-2) represented by the above-mentioned chemical formula (1-2) was obtained. When mass spectrometry was performed by MALDI, a peak with a molecular weight of 519 was detected.

[0068] (Synthesis Example 3) Production of Benzothiazole Derivative (1-3) Instead of 5.23 parts of 3-methyl-1-phenyl-2-pyrazolin-5-one used in Synthesis Example 1, 6.26 parts of 3-methyl-1-chlorophenyl-2-pyrazolin-5-one was used for synthesis. Otherwise, in the same manner as in Synthesis Example 1, 16.0 parts of the benzothiazole derivative (1-3) represented by the above-mentioned chemical formula (1-3) was obtained. When mass spectrometry was performed by MALDI, a peak with a molecular weight of 540 was detected.

[0069] <Preparation of Pigment Dispersion> (Example 1) Preparation of Orange Pigment Dispersion (1-1) Dissolve 12 parts of a dispersant (Solsperse 37500) in 73.0 parts of PEA, add 14.5 parts of PO43 and 0.5 part of the benzothiazole derivative (1-1) of Synthesis Example 1, and use a paint shaker with zirconia beads having a diameter of 1 mm to disperse so that the volume average particle diameter (median diameter; D 50 ) is 200 nm or less to prepare the orange pigment dispersion (1-1) of Example 1.

[0070] (Example 2) Preparation of Orange Pigment Dispersion (1-2) The orange pigment dispersion (1-2) of Example 2 was prepared in the same manner as in Example 1, except that 0.5 part of the benzothiazole derivative (1-2) was used instead of the benzothiazole derivative (1-1) used in Example 1.

[0071] (Example 3) Preparation of Orange Pigment Dispersion (1-3) Except that 0.5 part of benzothiazole derivative (1-3) was used instead of the benzothiazole derivative (1-1) used in Example 1, an orange pigment dispersion (1-3) of Example 3 was prepared in the same manner as in Example 1.

[0072] (Example 4) Preparation of orange pigment dispersion (1-4) Except that the amount of PO43 used in Example 1, 14.5 parts, and the amount of benzothiazole derivative (1-1) used, 0.5 part, were changed to 14.95 parts and 0.05 part, respectively, an orange pigment dispersion (1-4) of Example 4 was prepared in the same manner as in Example 1.

[0073] (Example 5) Preparation of orange pigment dispersion (1-5) Except that the amount of PO43 used in Example 1, 14.5 parts, and the amount of benzothiazole derivative (1-1) used, 0.5 part, were changed to 11.0 parts and 4.0 parts, respectively, an orange pigment dispersion (1-5) of Example 5 was prepared in the same manner as in Example 1.

[0074] (Comparative Example 1) Preparation of orange pigment dispersion (2) Except that Direct Yellow 8 was used instead of the benzothiazole derivative (1-1) used in Example 1, an orange pigment dispersion (2) of Comparative Example 1 was prepared in the same manner as in Example 1. In Comparative Example 1, Direct Yellow 8 having a structural part common to the chemical structure of the compound (benzothiazole derivative) represented by the general formula (1) was used for comparison.

[0075] (Comparative Example 2) Preparation of orange pigment dispersion (3) In Example 1, except that the benzothiazole derivative (1-1) was not added, an orange pigment dispersion (3) of Comparative Example 2 was prepared in the same manner as in Example 1.

[0076] (Evaluation of pigment dispersion) (Volume average particle diameter) For each prepared orange pigment dispersion, using a particle size distribution measuring device that utilizes the dynamic light scattering method (product name "FPAR-1000", manufactured by Otsuka Electronics Co., Ltd.), the volume average particle diameter (D 50 ) of PO43 in the pigment dispersion was measured.

[0077] (Storage stability) After accommodating the orange pigment dispersions immediately prepared in each example and comparative example in glass bottles, the glass bottles were sealed and stored at 60°C for 2 weeks. The viscosities at 25°C of the orange pigment dispersions before and after storage were measured using an E-type viscometer (product name "TV33-L", manufactured by Toki Sangyo Co., Ltd.). Then, it was calculated by what percentage the viscosity of the orange pigment dispersion after storage increased, that is, by what percentage it thickened, with respect to the viscosity of the orange pigment dispersion before storage. Based on the results, the storage stability of the pigment dispersion was evaluated according to the following evaluation criteria. The smaller the thickening, the better the storage stability of the orange pigment dispersion. "A" and "B" in the following evaluation criteria are acceptable levels, and "C" is an unacceptable level. A: The thickening is less than 5%. B: The thickening is 5% or more and less than 10%. C: The thickening is 10% or more.

[0078] (Pigment aggregation) The orange pigment dispersions immediately prepared in each example and comparative example were filtered using filter paper (manufactured by Advantec, No. 5A), and then the foreign substances remaining on the filter paper were visually observed. Based on the observation results, the degree of aggregation of the pigment (C.I. Pigment Orange 43) in the pigment dispersion was evaluated according to the following evaluation criteria. The less or no foreign substances are confirmed, the more difficult it is for PO43 in the orange pigment dispersion to aggregate. "A" and "B" in the following evaluation criteria are acceptable levels, and "C" is an unacceptable level. A: No foreign substances are observed. B: Some foreign substances are observed. C: Many foreign substances are observed.

[0079] The compositions (unit: parts) and evaluation results of the orange pigment dispersions of Examples 1 to 5 and Comparative Examples 1 and 2 are shown in Table 1 (Table 1-1 and Table 1-2).

[0080] TIFF0007691953000009.tif95170

[0081] TIFF0007691953000010.tif94169

[0082] <Preparation of Inkjet Ink> (Examples 6 to 8 and Comparative Examples 3 and 4) To the orange pigment dispersions obtained in Examples 1 to 3 and Comparative Examples 1 and 2, a polymerizable compound, a photopolymerization initiator, a photopolymerization inhibitor, and a slip agent were respectively blended so as to have the compositions shown in Table 2 below, and a non-aqueous orange ink, an inkjet ink curable by active energy rays (hereinafter, may be simply referred to as "ink") was prepared.

[0083] <Evaluation of Inkjet Ink> (Storage Stability) The ink immediately after preparation in each example and comparative example was placed in a glass bottle, the glass bottle was sealed, and stored at 60°C for 2 weeks. The viscosity of the ink at 25°C before and after storage was measured with an E-type viscometer (product name "TV33-L", manufactured by Toki Sangyo Co., Ltd.), and it was calculated by what percentage the viscosity of the ink after storage increased with respect to the viscosity of the ink before storage, that is, by what percentage the viscosity increased. Based on the results, the storage stability of the ink was evaluated according to the following evaluation criteria. The smaller the increase in viscosity, the better the storage stability of the ink. "A" and "B" in the following evaluation criteria are acceptable levels, and "C" is an unacceptable level. A: The increase in viscosity is less than 5%. B: The increase in viscosity is 5% or more and less than 10%. C: The increase in viscosity is 10% or more.

[0084] (Pigment Aggregation) The inks prepared in each of the examples and comparative examples were filtered using filter paper (Advantec, No. 5A), and then foreign substances remaining on the filter paper were visually observed. Based on the observation results, the degree of aggregation of the pigment (C.I. Pigment Orange 43) in the ink was evaluated according to the following evaluation criteria. The less or no foreign substances were confirmed, the more difficult it was for PO43 in the ink to aggregate. "A" and "B" in the following evaluation criteria are acceptable levels, and "C" is an unacceptable level. A: No foreign substances were observed. B: Some foreign substances were observed. C: Many foreign substances were observed.

[0085] Table 2 shows the compositions (unit: %) and evaluation results of the inkjet inks of Examples 6 to 8 and Comparative Examples 3 and 4.

[0086] TIFF0007691953000011.tif123170

Claims

1. A pigment dispersion containing a liquid medium, C.I. Pigment Orange 43, and a dispersant, wherein the dispersant contains at least one benzothiazole derivative selected from the group consisting of a compound represented by the following general formula (1), and its metal salts, ammonium salts, organic amine salts, and salts of organic quaternary ammonium compounds. (In the general formula (1), R １ represents an aryl group which may have a substituent.)

2. The pigment dispersion according to Claim 1, wherein the content of C.I. Pigment Orange 43 in the pigment dispersion is 1% by mass or more and 90% by mass or less based on the total mass of the pigment dispersion.

3. The pigment dispersion according to Claim 1 or 2, wherein the content of the benzothiazole derivative in the pigment dispersion is 0.05% by mass or more and 40% by mass or less based on the content of C.I. Pigment Orange 43 in the pigment dispersion.

4. The pigment dispersion according to any one of Claims 1 to 3, wherein the liquid medium contains at least one selected from the group consisting of an organic solvent and a polymerizable compound.

5. The pigment dispersion according to any one of Claims 1 to 4, which is a colorant for an active energy ray curable inkjet ink, a colorant for a gravure ink, a colorant for a paint, or a colorant for a color filter.

6. A coating agent containing the pigment dispersion according to any one of Claims 1 to 5.

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