Image recording composition and method for producing the same

Abstract

To provide an image recording composition with excellent storage stability that enables recording of images with little change in hue, and a method for producing the same.SOLUTION: The image recording composition contains a pigment composition, which comprises a yellow monoazo pigment and a compound represented by formula (1) or (2) different from the yellow monoazo pigment. The method for producing the image recording composition comprises a step of coupling a diazo component (c1), which is obtained by diazotizing 2-methoxy-4-nitroaniline, with a coupler component mixture (c2), which contains coupler components (a2) and (b2) that are acetoacetoanilide derivatives, thereby simultaneously synthesizing the yellow monoazo pigment and the compound represented by formula (1) or (2) to obtain a crude pigment composition.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an image recording composition and a method for producing the same. [Background technology]

[0002] Conventionally, pigments have been widely used as coloring materials for image recording such as inkjet recording, electrophotography, and thermal transfer recording from the viewpoint of fastness. Yellow azo pigments are widely used as yellow pigments. It is known that when a yellow azo pigment is micronized by a method such as solvent salt milling, various physical properties such as color development, color tone, coloring power, and transparency as well as heat resistance and light resistance are improved. In particular, in the case of inkjet ink, various properties are remarkably improved by micronizing the pigment.

[0003] When micronizing a yellow azo pigment, a pigment derivative (synergist) with a similar chemical structure may be used in combination with the pigment to suppress the crystal growth of the pigment. For example, it has been proposed to use a monoazo compound having various substituents such as an alkyl group or a sulfonic acid group as the pigment derivative (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 50-010324 Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventors have investigated the micronization of a yellow monoazo pigment in the presence of a pigment derivative. As a result, it has been found that when a pigment derivative in which the type and position of the substituent are not optimized is used, the micronization is insufficient, or the pigment particles tend to grow due to treatment such as heating, making it difficult to maintain the particle size. When a pigment in which crystal growth is not suppressed is used, the color tone of the recorded image is likely to change, and the image quality is likely to decrease. In particular, in the case of inkjet ink, it has been found that the color tone of the image changes significantly when a pigment in which crystal growth is not sufficiently suppressed is used.

[0006] The present inventors also prepared a pigment composition using a pigment that was micronized in the presence of the pigment derivative proposed in Patent Document 1, and investigated images recorded with an inkjet ink containing this pigment composition. As a result, it was found that the color tone of the recorded image was prone to change and the particle size of the pigment in the ink after storage increased due to insufficient inhibition of the pigment crystal growth.

[0007] Therefore, an object of the present invention is to provide an image recording composition having excellent storage stability and capable of recording an image whose color tone is unlikely to change. Another object of the present invention is to provide a method for producing an image recording composition having excellent storage stability and capable of recording an image whose color tone is unlikely to change. [Means for solving the problem]

[0008] The above object can be achieved by the present invention, which provides an image-recording composition comprising a pigment composition containing a yellow monoazo pigment and a compound represented by the following formula (1) or a compound represented by the following formula (2) that is different from the yellow monoazo pigment.

[0009] TIFF2025078475000001.tif43170 Effect of the Invention

[0010] According to the present invention, it is possible to provide an image recording composition having excellent storage stability and capable of recording an image whose color tone is unlikely to change. Also, according to the present invention, it is possible to provide a method for producing an image recording composition having excellent storage stability and capable of recording an image whose color tone is unlikely to change. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described in more detail below with reference to preferred embodiments. In the present invention, the inkjet ink may be simply referred to as "ink." The "unit" of a resin refers to the smallest repeating unit constituting the resin, and means a structure formed by (co)polymerization of one monomer. Physical property values ​​are values ​​at room temperature (25°C) unless otherwise specified.

[0012] The present inventors have investigated the reason why it is difficult to sufficiently micronize a yellow monoazo pigment when the pigment derivative is present in the pigment. As a result, it has been found that when a pigment derivative in which the type and position of the substituent are not optimized is used, the pigment derivative is not effectively adsorbed to the particle (crystal) surface of the yellow monoazo pigment, and the suppression of crystal growth is insufficient.

[0013] Generally, pigment particles grow and increase in particle size due to Ostwald ripening, in which particles grow to minimize the specific surface area of ​​the entire system in order to minimize the total interfacial energy between the pigment particle surface and the medium in the entire system, and coarse particles are formed. At this time, it is known that new pigment molecules are adsorbed to steps and kinks on the pigment crystal surface and incorporated into the crystal, thereby progressing crystal growth. If a pigment derivative (synergist) is present at this time, the pigment derivative molecules are adsorbed to the crystal surface and incorporated, and further pigment molecules are inhibited from adsorbing in the vicinity. It is believed that this reduces the particle growth rate and inhibits crystal growth.

[0014] Taking the above-mentioned mechanism into consideration, the present inventors have investigated the structure of pigment derivatives in order to significantly reduce the crystal growth rate and improve the crystal growth suppression effect. As a result, they have found that two properties of the pigment derivative, the adsorptive power and molecular planarity, are important. Below, the above two properties are explained using an example in which a yellow monoazo pigment is used as a pigment and a derivative of this yellow monoazo pigment is used as a pigment derivative.

[0015] (i) Adsorption strength The adsorption strength of a pigment derivative refers to the affinity between the pigment derivative and the pigment crystal surface. The higher the affinity between the two, the greater the adsorption strength of the pigment derivative to the pigment crystal surface, and the easier it is for the pigment derivative to be adsorbed to the pigment crystal surface. The affinity between a pigment derivative and a pigment crystal surface can be predicted by molecular orbital calculations using density functional theory. Specifically, the energy (E 1 ), and the energy of a system consisting of only one molecule of the pigment derivative (E 2 ), and the energy of the mixture in which one molecule of the pigment derivative is adsorbed on the pigment crystal surface at the most stable distance (E 1+2 ) and then E 1+2 -(E 1 +E 2 The smaller the value of E (larger negative value), the stronger the interaction between the pigment derivative and the pigment crystal surface, and the higher the affinity between them. 1+2 -(E 1 +E 2 The absolute value of E is the adsorption stabilization energy obtained when the pigment derivative is adsorbed on the pigment particle surface. 1+2 -(E 1 +E 2 ) is larger, the adsorption state is more stable, and the pigment derivative is more likely to be adsorbed onto the pigment crystal surface.

[0016] In order to increase the adsorption power of the pigment derivative, the above-mentioned adsorption stabilization energy can be increased, and a substituent that electronically interacts with the pigment crystal surface and has small steric interactions can be introduced into the pigment derivative molecule. As a result of the investigation, the present inventors found that the adsorption stabilization energy can be increased by introducing a methoxy group into the aromatic ring on the coupler side of the pigment derivative. Due to the characteristic electron density environment of the alkoxy group, the alkoxy group enhances the electronic interaction with the pigment crystal surface. Furthermore, it is believed that the introduction of a methoxy group, which has the shortest carbon chain among alkoxy groups, weakens the steric interaction with the pigment crystal surface. It is also believed that the methoxy group affects the π electron environment of the aromatic ring on the coupler side of the pigment derivative, enhancing the π-π interaction between the pigment crystal surface and the pigment derivative.

[0017] (ii) Molecular planarity The planarity of the entire molecule of the yellow monoazo pigment is maintained by strong hydrogen bonds between the two aromatic rings and the hydrazone (or azo) and amide moieties. In particular, if a substituent with an element that easily forms hydrogen bonds, such as an oxygen atom, is present in the ortho position of the aromatic ring on the coupler side, a strong intramolecular hydrogen bond is formed with the hydrogen atom bonded to the nitrogen atom of the amide moiety, increasing the planarity of the entire molecule. This is thought to facilitate regular arrangement of the pigment molecules and facilitate crystal growth. Therefore, the crystal growth of the pigment can be suppressed by adsorbing a pigment derivative that reduces the crystallinity of the pigment particle surface.

[0018] As a result of the investigation, the present inventors found that the crystallinity of the pigment derivative is reduced by making the ortho position of the aromatic ring on the coupler unsubstituted, and that the crystallinity of the pigment particle surface is reduced by the adsorption of this pigment derivative. When a hydrogen atom is present at the ortho position of the aromatic ring on the coupler side, an intramolecular hydrogen bond is not formed between the hydrogen atom bonded to the nitrogen atom of the amide site, and the planarity of the entire molecule is reduced, which is thought to reduce the crystallinity of the pigment derivative. In addition, since the ortho position is unsubstituted, the degree of freedom of rotation between the amide site and the aromatic ring is increased, which is thought to reduce the crystallinity of the pigment derivative. When a pigment derivative with low molecular planarity is adsorbed on the pigment particle surface, the planarity of the outermost surface of the pigment particle is reduced, making it difficult for the pigment molecules to be regularly arranged, and it is thought that the crystal growth of the pigment is suppressed.

[0019] Based on the above considerations, the present inventors have conducted various investigations into pigment derivatives capable of suppressing the crystal growth of a yellow monoazo pigment, and as a result, have found that the crystal growth of a yellow monoazo pigment can be significantly suppressed by using a compound represented by the following formula (1) or a compound represented by the following formula (2) as a pigment derivative, thereby completing the present invention.

[0020] TIFF2025078475000002.tif43170

[0021] As shown in formula (1), a methoxy group is introduced at the meta position of the aromatic ring on the coupler side. Also, as shown in formula (2), a methoxy group is introduced at the para position of the aromatic ring on the coupler side. Because a methoxy group is introduced at the aromatic ring on the coupler side, these compounds are strongly adsorbed to the pigment particle surface. Furthermore, because the ortho position of the aromatic ring on the coupler side is unsubstituted, these compounds have low planarity of the entire molecule and low crystallinity. For this reason, by using the compound represented by formula (1) or the compound represented by formula (2) as a pigment derivative and combining it with a yellow monoazo pigment, the crystal growth of the yellow monoazo pigment can be suppressed.

[0022] <Image Recording Composition> The image recording composition of the present invention is an image recording material containing a pigment composition including a yellow monoazo pigment and a compound represented by the following formula (1) or a compound represented by the following formula (2) different from the yellow monoazo pigment. That is, the image recording composition of the present invention is an image recording material suitably used for image recording such as inkjet recording, electrophotography, and thermal transfer recording. More specifically, the image recording composition of the present invention is a composition that can be used as an image recording material such as inkjet ink and electrophotographic toner by containing components such as appropriate resins, additives, carriers, and solvents. Hereinafter, the components constituting the image recording composition of the present invention will be described in detail.

[0023] TIFF2025078475000003.tif43170

[0024] (Yellow monoazo pigment) The image recording composition of the present invention contains a pigment composition including a yellow monoazo pigment and a compound represented by formula (1) or a compound represented by formula (2) (pigment derivative) different from the yellow monoazo pigment. The yellow monoazo pigment is an acetoacetanilide-based monoazo pigment having one azo group or one hydrazone group in the molecule and exhibiting a yellow hue. Specific examples of the yellow monoazo pigment include CI Pigment Yellow 1, CI Pigment Yellow 2, CI Pigment Yellow 3, CI Pigment Yellow 4, CI Pigment Yellow 5, CI Pigment Yellow 6, CI Pigment Yellow 9, CI Pigment Yellow 49, CI Pigment Yellow 65, CI Pigment Yellow 73, CI Pigment Yellow 74, CI Pigment Yellow 75, CI Pigment Yellow 97, CI Pigment Yellow 98, CI Pigment Yellow 111, CI Pigment Yellow 116, CI Pigment Yellow 130, CI Pigment Yellow 133, CI Pigment Yellow 169, and CI Pigment Yellow 203. Among these, the yellow monoazo pigment is preferably CI Pigment Yellow 74 (PY74), which is excellent in terms of hue and vividness.

[0025] Yellow monoazo pigments are usually synthesized by coupling a diazo component (a1) obtained by converting an aniline derivative into a diazonium salt with a coupler component (a2) that is an acetoacetanilide derivative. For example, CI Pigment Yellow 74 can be synthesized by coupling the diazo component (a1) obtained by converting 2-methoxy-4-nitroaniline into a diazonium salt with o-acetoacetanilide (coupler component (a2)).

[0026] (Compound represented by formula (1) and compound represented by formula (2)) The pigment composition used in the image recording composition of the present invention contains a compound represented by the following formula (1) or a compound represented by the following formula (2) (hereinafter also referred to as a "pigment derivative").

[0027] TIFF2025078475000004.tif43170

[0028] These compounds (pigment derivatives) have a molecular structure similar to that of the yellow monoazo pigment, so they are easily adsorbed to the surface of the pigment particles and can suppress the crystal growth of the pigment. In particular, when CI Pigment Yellow 74 is used as the yellow monoazo pigment, the crystal growth suppression effect is higher because the diazo side structure is common. In addition, these compounds are reddish in color compared to general yellow monoazo pigments such as CI Pigment Yellow 74. Therefore, by adsorbing them to the yellow monoazo pigment at a specific ratio, the hue of the image can be appropriately controlled.

[0029] The compound represented by formula (1) and the compound represented by formula (2) can be synthesized, for example, by the same method as that for the yellow monoazo pigment. That is, these compounds can be synthesized by coupling a diazo component (b1) obtained by converting an aniline derivative into a diazonium salt with a coupler component (b2) that is an acetoacetanilide derivative. Specifically, the compound represented by formula (1) can be synthesized by coupling a diazo component (b1) obtained by converting 2-methoxy-4-nitroaniline into a diazonium salt with m-acetoacetanisidide, which is the coupler component (b2). The compound represented by formula (2) can be synthesized by coupling a diazo component (b1) obtained by converting 2-methoxy-4-nitroaniline into a diazonium salt with p-acetoacetanisidide, which is the coupler component (b2).

[0030] In the image recording composition, the content (mass%) of the compound represented by formula (1) or the compound represented by formula (2) is preferably 0.001 times or more and 0.100 times or less in mass ratio to the content (mass%) of the yellow monoazo pigment. It is more preferably 0.010 times or more and 0.080 times or less. If the mass ratio is less than 0.001 times, the crystal growth suppression effect may be insufficient. On the other hand, if the mass ratio is more than 0.100 times, the color of the pigment composition may easily deviate from the color of the main component yellow monoazo pigment due to the influence of the color of the pigment derivative, which is a secondary component. The main component of the pigment composition is the yellow monoazo pigment, which is a component with a large mass ratio in the pigment composition. The secondary component of the pigment composition is the pigment derivative (the compound represented by formula (1) or the compound represented by formula (2)), which is a component with a small mass ratio in the pigment composition.

[0031] (Pigment Composition) The image recording composition of the present invention contains a pigment composition including a yellow monoazo pigment and a compound represented by the following formula (1) or a compound represented by the following formula (2) that is different from the yellow monoazo pigment. It is preferable that the pigment composition is substantially composed of the yellow monoazo pigment and the compound represented by the following formula (1) or the compound represented by the following formula (2) (pigment derivative).

[0032] TIFF2025078475000005.tif43170

[0033] The pigment composition is preferably formed by physically adsorbing the compound represented by formula (1) or the compound represented by formula (2) to the particle surface of the yellow monoazo pigment. That is, molecules or microcrystalline particles of the pigment derivative, which is a secondary component, are physically adsorbed to at least a part of the particle (crystal) surface of the yellow monoazo pigment, which is the main component in the pigment composition. For this reason, for example, the surface (particle surface) of the pigment composition, which is a granular material, is composed of the particle surface of the yellow monoazo pigment, which is the main component, and the crystal surface of the pigment derivative, which is the secondary component. It is difficult to form such a surface state of the pigment composition by simply mixing the yellow monoazo pigment and the pigment derivative (for example, powder or particulate). A method for producing the pigment composition will be described later.

[0034] (rosins) The pigment composition is preferably a surface-treated product in which the particle surfaces are treated with a rosin. By using a pigment composition in which the particle surfaces are treated with a rosin, the crystal growth inhibitory effect of the compound represented by formula (1) or formula (2) can be further enhanced.

[0035] Examples of rosins include rosin, rosin ester, hydrogenated rosin, hydrogenated rosin ester, disproportionated rosin, disproportionated rosin ester, and rosin amine. Among these, rosin amine is preferred. The rosins may be used alone or in combination of two or more.

[0036] In the image recording composition, the content of the rosins (mass%) is preferably 0.001 times or more and 0.050 times or less, more preferably 0.005 times or more and 0.030 times or less, in terms of mass ratio to the content of the yellow monoazo pigment (mass%). If the mass ratio is less than 0.001 times, the amount of rosins physically adsorbed on the particle surface of the yellow monoazo pigment may be slightly insufficient, and the crystal growth inhibition effect obtained by surface treatment with rosins may be insufficient. On the other hand, if the mass ratio is more than 0.050 times, the amount of rosins free from the particle surface of the pigment composition may increase. Therefore, when the image recording composition is used as, for example, an inkjet ink, the storage stability and ejection performance of the ink may be slightly decreased.

[0037] <Ink> The image recording composition of the present invention is a suitable composition for use as an image recording agent such as an inkjet ink and an electrophotographic toner, etc. Hereinafter, the image recording composition used as an inkjet ink will be described in detail.

[0038] The ink contains a pigment composition containing a yellow monoazo pigment and a compound represented by formula (1) or a compound represented by formula (2) (pigment derivative) as a coloring material. The content (mass %) of the pigment composition in the ink is preferably 0.1 mass % or more and 15.0 mass % or less, and more preferably 1.0 mass % or more and 10.0 mass % or less, based on the total mass of the ink.

[0039] Examples of pigment dispersion methods include resin-dispersed pigments that use a resin (resin dispersant) as a dispersant, and self-dispersed pigments in which hydrophilic groups are bonded to the pigment particle surface. Other examples include resin-bonded pigments in which an organic group containing a resin is chemically bonded to the pigment particle surface, and microcapsule pigments in which the pigment particle surface is coated with a resin. Of these, it is preferable to use resin-dispersed pigments in which a resin as a dispersant is physically adsorbed onto the pigment particle surface, rather than resin-bonded pigments or microcapsule pigments.

[0040] The ink may further contain other pigments other than the pigment composition. In particular, it is preferable to further contain an azo pigment that exhibits a yellow hue. The content (mass %) of the other pigments in the ink is preferably 0.1% by mass or more and 5.0% by mass or less, and more preferably 0.1% by mass or more and 1.0% by mass or less, based on the total mass of the ink.

[0041] (resin) The ink may contain a resin. The content (mass %) of the resin in the ink is preferably 0.1% by mass to 5.0% by mass based on the total mass of the ink. Also, the content is more preferably 0.3% by mass to 2.0% by mass, and particularly preferably 0.5% by mass to 1.5% by mass.

[0042] The resin can be contained in the ink for the purposes of (i) stabilizing the dispersion state of the pigment, i.e., as a resin dispersant for the pigment or as an auxiliary thereof, and (ii) improving various properties of the recorded image. In particular, since the ink preferably contains a resin-dispersed pigment, the resin is preferably a resin dispersant. In other words, it is preferable that the ink contains a resin dispersant in addition to the above-mentioned pigment derivative.

[0043] The form of the resin may be a block copolymer, a random copolymer, a graft copolymer, or a combination thereof. The resin may be a soluble resin that can be dissolved in a liquid medium, or may be resin particles that are dispersed in the liquid medium. The resin particles do not need to encapsulate a coloring material.

[0044] In this specification, "a resin is soluble" means that when the resin is neutralized with an alkali equivalent to the acid value, the resin is present in a liquid medium in a state in which it does not form particles whose particle size can be measured by dynamic light scattering. Whether or not a resin is soluble can be determined according to the following method. First, a liquid (resin solid content: 10 mass%) containing a resin neutralized with an alkali (sodium hydroxide, potassium hydroxide, etc.) equivalent to the acid value is prepared. Next, the prepared liquid is diluted 10 times (volume basis) with pure water to prepare a sample solution. Then, when the particle size of the resin in the sample solution is measured by dynamic light scattering, if particles having a particle size are not measured, the resin can be determined to be soluble. The measurement conditions at this time can be, for example, SetZero: 30 seconds, number of measurements: 3 times, and measurement time: 180 seconds. As a particle size distribution measuring device, a particle size analyzer using a dynamic light scattering method (for example, product name "UPA-EX150", manufactured by Nikkiso) can be used. Of course, the particle size distribution measuring device and the measurement conditions are not limited to those described above.

[0045] Examples of the resin include acrylic resins, urethane resins, and urea resins. Among them, acrylic resins are preferred, and acrylic resins having hydrophilic and hydrophobic units are more preferred. When the resin is used as a resin dispersant for aqueous inks, acrylic resins having a hydrophilic unit derived from (meth)acrylic acid and a hydrophobic unit derived from a monomer having an aliphatic group or an aromatic ring are preferred. Furthermore, it is preferred to use an acrylic resin having a hydrophilic unit derived from (meth)acrylic acid and a hydrophobic unit derived from at least one monomer of styrene and α-methylstyrene as a resin dispersant. These resin dispersants are suitable because they are particularly prone to interact with pigments.

[0046] The hydrophilic unit is a unit having a hydrophilic group such as a hydroxy group or an ethylene oxide group. The hydrophilic unit can be formed, for example, by polymerizing a hydrophilic monomer having a hydrophilic group. Examples of the hydrophilic monomer include 2-hydroxyethyl (meth)acrylate and (poly)ethylene glycol (meth)acrylate. The hydrophobic unit is a unit not having a hydrophilic group such as an anionic group, a hydroxy group, or an ethylene oxide group. The hydrophobic unit can be formed, for example, by polymerizing a hydrophobic monomer not having the above-mentioned hydrophilic group. Examples of the hydrophobic monomer include (meth)acrylic acid ester monomers such as ethyl (meth)acrylate, methyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.

[0047] When a resin is used as a resin dispersant for an oil-based ink, examples of the resin include hydroxy group-containing carboxylic acid esters, salts of polyaminoamides and polymeric acid esters, salts of polycarboxylic acids, salts of polar acid esters such as polyaminoamides and sulfuric acid esters, unsaturated acid esters, copolymers of vinylpyrrolidone and alkenes, modified polyurethanes, modified polyacrylates, polyether ester-type anionic surfactants, polyoxyethylene alkyl phosphates, and polyester polyamines. Examples of modified polyurethanes and modified polyacrylates include those that are epoxy-modified or acrylic-modified.

[0048] The weight average molecular weight of the resin is preferably 1,000 to 30,000, more preferably 5,000 to 15,000. The weight average molecular weight of the resin is a value calculated as polystyrene by gel permeation chromatography (GPC). The acid value of the resin is preferably 80 mgKOH / g to 250 mgKOH / g, more preferably 100 mgKOH / g to 200 mgKOH / g.

[0049] The ink may further contain other resins in addition to the above-mentioned resins. The content (mass %) of the other resins in the ink is preferably 0.1 mass % or more and 5.0 mass % or less based on the total mass of the ink.

[0050] (liquid medium) Ink usually contains a liquid medium. As the liquid medium of oil-based ink, it is preferable to use a water-insoluble organic solvent such as hydrocarbon compounds, ketones, ethers, acetates, and aromatic compounds. Water-soluble organic solvents described later may also be used. These organic solvents may be used alone or in combination as long as they form a single phase. The content (mass %) of the organic solvent in the oil-based ink is preferably 60.0 mass % or more and 95.0 mass % or less, and more preferably 80.0 mass % or more and 95.0 mass % or less, based on the total mass of the ink.

[0051] As the liquid medium of the aqueous ink, it is preferable to use water or an aqueous medium which is a mixed solvent of water and a water-soluble organic solvent. As the water, it is preferable to use deionized water (ion-exchanged water). The content (mass%) of water in the ink is preferably 50.0 mass% or more and 95.0 mass% or less based on the total mass of the ink. There is no particular limitation on the water-soluble organic solvent that can be used in the aqueous ink, so long as it is water-soluble (preferably, dissolves in water at any ratio at 25°C). Specifically, monohydric or polyhydric alcohols, alkylene glycols, glycol ethers, nitrogen-containing polar compounds, and sulfur-containing polar compounds can be used. The content (mass%) of the water-soluble organic solvent in the ink is preferably 5.0 mass% or more and 90.0 mass% or less based on the total mass of the ink, and more preferably 10.0 mass% or more and 50.0 mass% or less.

[0052] (Other additives) The ink may contain various additives such as surfactants, pH adjusters, preservatives, antifungal agents, antioxidants, reduction inhibitors, evaporation promoters, and chelating agents, as necessary. Of these, it is preferable that the ink contains a surfactant. The content (mass %) of the surfactant in the ink is preferably 0.1% by mass or more and 5.0% by mass or less, and more preferably 0.1% by mass or more and 2.0% by mass or less, based on the total mass of the ink. Examples of the surfactant include anionic surfactants, cationic surfactants, and nonionic surfactants.

[0053] (Ink properties) Since the ink is applied to the inkjet method, it is preferable to appropriately control the physical properties of the ink. The surface tension of the ink at 25°C is preferably 10 mN / m or more and 60 mN / m or less, and more preferably 20 mN / m or more and 40 mN / m or less. The surface tension of the ink can be adjusted by appropriately setting the type and content of the surfactant in the ink. The viscosity of the ink at 25°C is preferably 1.0 mPa·s or more and 10.0 mPa·s or less. When the ink is a water-based ink, the pH of the ink at 25°C is preferably 5.0 or more and 10.0 or less.

[0054] <Method of manufacturing image-recording composition> The method for producing the image-recording composition of the present invention includes the following steps. [1] A first step for producing a pigment composition containing a yellow monoazo pigment and a compound represented by formula (1) or a compound represented by formula (2) [2] The second step is to process the pigment composition according to each image recording method. [3] The third step is mixing the treated pigment composition with other components required for each image recording method.

[0055] <Ink manufacturing method> Among the image recording compositions, a method for producing an inkjet ink will be described in detail below. The method for producing the ink includes the following steps. [1] A first step for producing a pigment composition containing a yellow monoazo pigment and a compound represented by formula (1) or a compound represented by formula (2) [2] The second step of producing a pigment dispersion using the pigment composition [3] The third step is to mix the pigment dispersion with other components required for the inkjet recording method.

[0056] (First step: Production of pigment composition) The pigment composition can be produced according to the method described below. From the viewpoint of producing a pigment dispersion liquid, it is preferable that the pigment in the pigment composition is finely divided.

[0057] (i) Mixed coupling reaction The pigment composition can be produced, for example, by a so-called "mixed coupling reaction" in which a yellow monoazo pigment and a compound represented by formula (1) or a compound represented by formula (2) (pigment derivative) are simultaneously synthesized in the same system. Specifically, a diazo component (c1) obtained by converting 2-methoxy-4-nitroaniline into a diazonium salt is coupled with a coupler component mixture (c2) containing a coupler component (a2) and a coupler component (b2) that are acetoacetanilide derivatives. The diazo component (c1) means a common diazo component in the case where the diazo component (a1) for the yellow monoazo pigment and the diazo component (b1) for the pigment derivative are the same component. In this way, a crude pigment composition containing a yellow monoazo pigment and a pigment derivative can be obtained by a "mixed coupling reaction" in which the diazo component (c1) and the coupler component mixture (c2) are coupled. In addition, by coupling the diazo component (c1), a yellow monoazo pigment and a pigment derivative having the same molecular structure portion derived from a diazonium salt can be simultaneously synthesized. The yellow monoazo pigment produced by this "mixed coupling reaction" has a high structural similarity to the pigment derivative molecule, and the pigment derivative is easily adsorbed to the crystal surface of the yellow monoazo pigment. This makes it possible to obtain an image recording composition containing a highly finely divided pigment composition that has an excellent crystal growth suppression effect.

[0058] (ii) Solvent Salt Milling Method The pigment composition can be produced by wet kneading and grinding a crude mixture (pretreated mixture) containing a crude yellow monoazo pigment and a crude compound represented by formula (1) or a crude compound represented by formula (2) by a solvent salt milling method. The crude mixture may be a crude pigment composition obtained by the above-mentioned mixing and coupling reaction, or may be a mixture containing a crude yellow monoazo pigment and a crude pigment derivative that are separately produced. In particular, it is preferable to wet knead and grind the crude pigment composition obtained by the mixing and coupling reaction by a solvent salt milling method, since this makes it possible to obtain a pigment composition in which the yellow monoazo pigment and the pigment derivative are more uniformly mixed.

[0059] In addition, when a mixture (crude mixture) containing a crude yellow monoazo pigment and a crude pigment derivative produced separately is wet kneaded and pulverized by the solvent salt milling method, it is preferable to pretreat the crude mixture. That is, at least a part of the crude mixture is dissolved in an organic solvent, and then at least a part of the organic solvent is removed from the crude mixture. Then, it is preferable to physically adsorb the compound represented by formula (1) or the compound represented by formula (2) onto the particle surface of the yellow monoazo pigment to obtain a pretreated mixture. By pretreating the crude mixture, it is possible to perform solvent salt milling in a state in which at least a part of the pigment derivative is physically adsorbed onto the particle surface of the yellow monoazo pigment. This allows the yellow monoazo pigment and the pigment derivative to be mixed more uniformly.

[0060] To obtain a pigment composition in which the particle surfaces are treated with rosins, first, rosins are added to a synthesis system of a yellow monoazo pigment to obtain a crude yellow monoazo pigment in which the particle surfaces are treated with rosins. Then, a crude mixture containing the obtained crude yellow monoazo pigment and a crude compound represented by formula (1) or a crude compound represented by formula (2) is subjected to solvent salt milling. Alternatively, rosins may be added to the reaction system of the mixed coupling reaction to obtain a pigment composition in which the particle surfaces are treated with rosins.

[0061] (Solvent Salt Milling Method) As a method for reducing the size of coarse pigment particles, a wet kneading and pulverizing method such as a salt milling method and a dry pulverizing method are known. Among them, the wet kneading and pulverizing method using the solvent salt milling method is preferred because it is possible to obtain a more uniform pigment composition.

[0062] The solvent salt milling method is a method in which pigment particles are mechanically ground using a kneader or the like in the presence of a water-soluble inorganic salt (salt) and an organic solvent (solvent), and is a method that can efficiently reduce the size of pigment particles. The solvent salt milling method usually includes a kneading step of producing a kneaded product of the pigment, etc. in the presence of the water-soluble inorganic salt and the organic solvent, and a subsequent step of removing the water-soluble inorganic salt and the organic solvent.

[0063] [Water-soluble inorganic salts] Inorganic salts are used to pulverize and micronize pigments during the kneading process, taking advantage of their high hardness. Taking into consideration the ease of handling during removal, it is preferable to use inorganic salts that are water-soluble (water-soluble inorganic salts). Examples of water-soluble inorganic salts include chlorides of alkali metals such as sodium chloride and potassium chloride; chlorides of polyvalent metals such as zinc chloride and magnesium chloride; and the like.

[0064] The cumulative 50% particle size (D 50The cumulative 95% particle diameter (D) of the water-soluble inorganic salt based on the volume is preferably 1 μm or more and 50 μm or less. 95 ) is preferably 80 μm or less. 50 and D. 95 are the diameters of particles that are 50% and 95% of the total volume of the measured particles, calculated from the small particle size side, in the particle size integration curve. 50 and D. 95 can be measured, for example, using a particle size analyzer using dynamic light scattering.

[0065] [Organic solvents] The organic solvent is used in the kneading step to wet the pigment particles, the pigment derivative, and the water-soluble inorganic salt to increase the grinding effect and promote the fineness of the pigment. As the organic solvent, water-soluble organic solvents such as alcohols, glycols, and ethers are preferred. Among them, water-soluble organic solvents with high viscosity such as ethylene glycol, diethylene glycol, and polyethylene glycol are more preferred from the viewpoint of improving the grinding effect.

[0066] [Mixing process] The kneading step is a step of kneading a mixture of a pigment and a pigment derivative in the presence of a water-soluble inorganic salt and an organic solvent while compressing the mixture under a load. Examples of the apparatus used in the kneading step include a kneader, a roll mill, a ball mill, an attritor, a sand mill, and a planetary mixer. Among these, it is preferable to use a kneader.

[0067] The amount (mass%) of the compound represented by formula (1) or the compound represented by formula (2) used in the kneading step is preferably 0.001 to 0.100 times the amount (mass%) of the yellow monoazo pigment used. More preferably, it is 0.01 to 0.07 times. If the mass ratio is less than 0.001, the crystal growth inhibition effect may be insufficient. On the other hand, if the mass ratio is more than 0.100, the color of the pigment composition may easily deviate from the color of the yellow monoazo pigment, which is the main component, due to the influence of the color of the pigment derivative, which is the secondary component.

[0068] The temperature during the kneading step is preferably 25°C or higher and 90°C or lower. If the temperature is lower than 25°C, the pigment particles may be excessively fined, and the light resistance of the image may be insufficient. On the other hand, if the temperature is higher than 90°C, the pigment crystal growth rate may be excessively fast. As a result, the pigment particles are not easily fined, and the color development of the image may be insufficient.

[0069] [Post-process] The post-process is a process for removing the water-soluble inorganic salt and the organic solvent from the kneaded product obtained in the kneading process. Specifically, water is added to the kneaded product in a predetermined ratio to form a slurry, and the slurry is filtered and washed. As the water, it is preferable to use ion-exchanged water or pure water. Methods for filtering the slurry include a method of passing the slurry through an ultrafiltration membrane or a dialysis membrane for separation, and a method of separating the slurry using a high-pressure filter press. By carrying out the post-process, a pigment composition in which the organic solvent and the water-soluble inorganic salt have been reduced or removed can be obtained in the form of a wet cake.

[0070] In order to inhibit bacterial growth, the pigment composition obtained in the form of a wet cake is preferably dried until the water content (moisture content) is 5% by mass or less. In particular, when preparing a pigment dispersion for oil-based ink, it is preferable to dry until the water content is 0%. Methods for removing water include, for example, a batch or continuous drying method in which the mixture is heated to 80 to 120°C by a heat source installed in the dryer to dehydrate, and a drying method under reduced pressure. As the dryer, a box dryer, a band dryer, a spray dryer, and the like can be used.

[0071] (Second step: Production of pigment dispersion) By using the pigment composition, for example, a pigment dispersion liquid used for producing an inkjet ink can be obtained. Specifically, the pigment composition is dispersed in a liquid medium to obtain a pigment dispersion liquid. If necessary, an additive such as a pH adjuster may be used. Furthermore, it is also preferable to carry out a treatment to obtain a desired particle size distribution, such as applying a shear force.

[0072] Examples of the pigment dispersion method include resin-dispersed pigment, self-dispersed pigment, resin-bonded pigment, and microcapsule pigment. Among them, resin-dispersed pigment is preferable. When preparing a pigment dispersion using a pigment composition, a known dispersion method such as media dispersion or media-less dispersion can be adopted. Examples of dispersing machines using media dispersion include paint shakers, bead mills, sand mills, ball mills, and roll mills. Examples of dispersing machines using media-less dispersion include ultrasonic homogenizers and high-pressure homogenizers. Two or more types of dispersing machines may be used in combination during dispersion.

[0073] The temperature when dispersing the pigment composition in the liquid medium (during the dispersion treatment) can be set arbitrarily. When dispersing the pigment composition in an aqueous liquid medium, the temperature is preferably set to 0°C or more and 100°C or less. When heat is generated during the dispersion treatment or a media dispersion method is adopted, the temperature is preferably set to 10°C or more and 40°C or less from the viewpoint of media reliability. The time of the dispersion treatment may be adjusted according to the device used and the concentration of the pigment dispersion liquid. In addition, a preliminary dispersion treatment may be performed to mix the components containing the pigment composition, wet them into the liquid medium, and make them easier to disperse. The above-mentioned dispersion method and device can be adopted in the preliminary dispersion treatment.

[0074] [Liquid medium] When preparing a pigment dispersion for aqueous ink, an aqueous liquid medium is used. As the aqueous liquid medium, water or an aqueous medium using water as a main solvent in combination with an organic solvent can be used. As the organic solvent, it is preferable to use one that is miscible or soluble with water at any ratio. In particular, it is preferable to use a uniform mixed solvent containing 50% by mass or more of water as the aqueous medium. As the water, it is preferable to use ion-exchanged water or pure water.

[0075] As the organic solvent, a protic organic solvent or an aprotic organic solvent can be used. In addition, a protic organic solvent and an aprotic organic solvent may be used in combination. A protic organic solvent is an organic solvent having a hydrogen atom (acidic hydrogen atom) bonded to an oxygen atom or a nitrogen atom. In addition, an aprotic organic solvent is an organic solvent having no acidic hydrogen atom. Examples of the organic solvent include alcohols, alkylene glycols, polyalkylene glycols, glycol ethers, glycol ether esters, carboxylic acid amides, ketones, ketoalcohols, cyclic ethers, nitrogen-containing compounds, and sulfur-containing compounds.

[0076] [Post-processing] The produced pigment dispersion can be used for producing inkjet inks, preferably after general post-treatment such as purification. When only water is used as the liquid medium without using an organic solvent, the obtained dispersion can be used for producing ink as it is, or the final dispersion can be obtained after washing or adjusting the pigment content. When a liquid medium containing an organic solvent is used, the organic solvent may be removed. Examples of methods for removing the organic solvent include a method of adding water while removing the organic solvent by reducing pressure or heating using an evaporator or the like. Furthermore, there is also a method of repeating the operation of removing the organic solvent by ultrafiltration or the like and then adding water.

[0077] (Step 3: Ink production) A desired ink can be obtained by mixing the pigment dispersion with other components necessary for the inkjet recording method. Examples of the other components include water, a water-soluble organic solvent, a water-insoluble organic solvent, a resin, and the above-mentioned "other additives." For example, the desired ink can be prepared by putting the pigment dispersion and other ink components into a suitable container and stirring them. Conditions such as the stirring speed, temperature, and time can be set appropriately. Other known manufacturing processes may also be combined. EXAMPLES

[0078] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples without departing from the gist of the invention. "Parts" and "%" used to describe the amounts of components are based on mass unless otherwise specified.

[0079] <Analysis of pigments> ( 1 H-NMR analysis) 1 H-NMR analysis was carried out under the following conditions. [ 1 H-NMR analysis conditions] Measurement device: Nuclear magnetic resonance spectrometer (NMR) (product name "AVANCE III 500MHz", manufactured by Bruker Biospin) Solvent used: deuterated chloroform (CDCl 3 )

[0080] (High performance liquid chromatography mass spectrometry) High performance liquid chromatography mass spectrometry (HPLC / MS) was carried out under the following conditions. [HPLC analysis conditions] Column: Silica gel column (product name "SunFire C18 Column", 2.1 mm x 150 mm, manufactured by Waters) Column temperature: 40℃ ·Flow rate: 0.2mL / min Detector: Diode array (PDA) detector Detection range: 200nm~700nm ·Analysis time: 45 minutes Mobile phase gradient conditions: Table 1 below Sample solution: Dimethyl sulfoxide (DMSO) solution with a pigment concentration of 30 ppm Sample solution injection volume: 2μL

[0081] TIFF2025078475000006.tif35170

[0082] [Mass spectrometry conditions] Mass spectra were measured under the following conditions for the peaks obtained in the HPLC analysis performed under the above conditions. The most strongly detected m / z was measured for each of the positivity (ES+) and negativity (ES-). Ionization method: Electrospray ionization (ESI) Capillary voltage: 3.5kV Desolvation gas: 350℃ Ion source temperature: 120℃ Detector: 40V, 200~1,500amu / 0.9sec (for posi(ES+)); 40V, 200~1,500amu / 0.9sec (for nega(ES-))

[0083] [Measurement of the mass ratio of each pigment component in a pigment mixture] The mixed pigment sample was analyzed by HPLC analysis performed under the above conditions, and the peak area of ​​each pigment component in the mixed pigment obtained on the chromatogram at a detection wavelength of 254 nm was measured. At the same time, a standard DMSO solution for calibration curves with a pigment concentration of 30 ppm for each pigment component alone was also analyzed, and a concentration calibration curve for each pigment component at a detection wavelength of 254 nm was created. Then, the pigment concentration of each pigment component in the mixed pigment sample was calculated from the created concentration calibration curve, and the mass ratio of each pigment component in the mixed pigment was determined.

[0084] [Measurement of the mass ratio of rosins in pigments] The pigment sample was analyzed by HPLC analysis performed under the above conditions. Next, the area of ​​the MS count peak of the rosins obtained on the MS chromatogram at the m / z of the target rosins was measured. At the same time, a standard DMSO solution for a calibration curve with a concentration of 1 ppm of the target rosins alone was also analyzed, and a concentration calibration curve of the target rosins was created. Then, the concentration of the rosins in the pigment sample was calculated from the created concentration calibration curve, and the mass ratio of the rosins in the pigment was obtained.

[0085] <Synthesis of raw materials> (Synthesis Example 1) 10.0 parts of m-anisidine was added to 240 parts of ion-exchanged water heated to 50°C, and the mixture was stirred and heated to 100°C. 18.2 parts of 2,2,6-trimethyl-1,3-dioxin-4-one was added, and the mixture was heated to 100°C and stirred for 2.5 hours. After cooling, 35.0 parts of 2mol / L hydrochloric acid was added and stirred. The extract obtained using ethyl acetate was washed with a saturated aqueous sodium chloride solution and then dried over sodium sulfate. After removing the sodium sulfate, the ethyl acetate was distilled off with an evaporator to obtain a viscous substance. The obtained viscous substance was cooled and left to stand, whereupon it crystallized, and 10.7 parts of m-acetoacetanisidide was obtained as a light brown solid (yield 64%).

[0086] 1 The results of the analysis of m-acetoacetaniside by H-NMR are shown below. [ 1 H-NMR] δ(ppm):9.09(s,1H),7.28(m,1H),7.21(t,1H),7.03(d,1H),6.67(dd,1H),3.80(s,3H),3.58(s,2H),2.32(s,3H)

[0087] <Production of pigment derivatives> (Syn01) 10.1 parts of 2-methoxy-4-nitroaniline was added to 108.84 parts of ion-exchanged water and stirred to prepare a suspension. 13.0 parts of 35% hydrochloric acid was added and stirred for 1 hour, and then cooled in an ice-salt bath until the internal temperature was 0°C or lower. An aqueous solution of sodium nitrite prepared by adding 10.8 parts of ion-exchanged water to 4.18 parts of sodium nitrite was added, and the internal temperature was maintained at 0°C or lower in an ice-salt bath and stirred for 1 hour to convert it into diazonium salt, thereby obtaining a diazonium salt solution. 0.059 parts of sulfamic acid was added to the obtained diazonium salt solution to remove excess nitrous acid, and a diazo component solution was prepared.

[0088] 12.2 parts of m-acetoacetaniside, 6.14 parts of sodium hydroxide, and 96.7 parts of ion-exchanged water were mixed and stirred to obtain a liquid. The above liquid was added to an aqueous solution of 9.84 parts of acetic acid and 65.4 parts of ion-exchanged water, and the mixture was stirred to prepare a coupler component slurry.

[0089] The coupler component slurry was heated to 40°C using a hot stirrer, and the diazo component solution was added dropwise over 30 minutes while maintaining the internal temperature at 40°C. After stirring at 40°C for 30 minutes, the internal temperature was raised to 70°C and stirred for 20 minutes to complete the reaction. The reaction solution was filtered to remove the reaction precipitate, which was washed three times with an appropriate amount of ion-exchanged water to obtain a crude cake of the reaction product. Ethanol was added to the obtained crude cake, which was stirred for 1 hour to wash. The filtered precipitate was dried to obtain 21.9 parts of Syn01 (yield 96%).

[0090] 1 The results of the analysis of Syn01 by H-NMR and HPLC / MS are shown below. [1 H-NMR] δ(ppm):14.74(s,1H),11.34(s,1H),7.99(dd,1H),7.84(d,1H),7.74(d,1H),7.33(dd ,1H),7.28(t,1H),7.19(dd,1H),6.73(dd,1H),4.08(s,3H),3.84(s,3H),2.63(s,3H) [HPLC / MS] Measured value: MS(ES+) m / z 387.31(M+H) + MS(ES-)m / z 385.33(MH) - Calculated value: C 18 H 18 N 4 O 6 =386.12

[0091] (Syn02) Except for using 12.2 parts of p-acetoacetanisidide instead of 12.2 parts of m-acetoacetanisidide, the same procedure as in the case of Syn01 described above was carried out to obtain 21.2 parts of Syn02 (yield 93%).

[0092] 1 The results of the analysis of Syn02 by H-NMR and HPLC / MS are shown below. [ 1 H-NMR] δ(ppm):14.77(s,1H),11.21(s,1H),7.98(dd,1H),7.83(d,1H),7.72(d,1H),7.55(d,2H),6.92(d,2H),4.06(s,3H),3.82(s,3H),2.62(s,3H) [HPLC / MS] Measured value: MS(ES+) m / z 387.40(M+H) + MS(ES-)m / z 385.39(MH) - Calculated value: C 18 H 18 N 4 O 6 =386.12

[0093] (Comparative compound 1) A pigment derivative (Synergist) described in Patent Document 1 was produced as Comparative Compound 1. Specifically, 22.5 parts of Comparative Compound 1 represented by the following formula (A) were obtained (yield 92%) in the same manner as in the case of Syn01 described above, except that 14.0 parts of 2',5'-dimethoxyacetoacetanilide was used instead of 12.2 parts of m-acetoacetanisidide.

[0094] The results of the analysis of Comparative Compound 1 by HPLC / MS are shown below. [HPLC / MS] Measured value: MS(ES+) m / z 417.35(M+H) + MS(ES-)m / z 415.33(MH) - Calculated value: C 19 H 20 N 4 O 7 =416.13

[0095] (Comparative compound 2) A pigment composition (Synergist) was produced as Comparative Compound 2, which was synthesized from the exemplary raw materials described in Patent Document 1. Specifically, except that 13.0 parts of 4'-ethoxyacetoacetanilide was used instead of 12.2 parts of m-acetoacetanilide, 21.4 parts of Comparative Compound 2 represented by the following formula (B) were obtained in the same manner as in the case of Syn01 described above (yield 91%).

[0096] The results of the analysis of Comparative Compound 2 by HPLC / MS are shown below. [HPLC / MS] Measured value: MS(ES+) m / z 401.34(M+H) + MS(ES-)m / z 399.33(MH) - Calculated value: C 19 H 20 N 4 O 6 =400.14

[0097] TIFF2025078475000007.tif41170

[0098] <Production of mixed coupling product> (Mixed coupling product 1) 50.4 parts of 2-methoxy-4-nitroaniline were added to 360 parts of ion-exchanged water, and the mixture was stirred to prepare a suspension. 78.1 parts of 35% hydrochloric acid were added and stirred for 1 hour, and then the mixture was cooled in an ice-salt bath until the internal temperature was 0°C or lower. An aqueous solution of sodium nitrite prepared by adding 53.7 parts of ion-exchanged water to 20.9 parts of sodium nitrite was added, and the mixture was stirred for 1 hour while maintaining the internal temperature at 0°C or lower in an ice-salt bath to convert the mixture into diazonium salt, thereby obtaining a diazonium salt solution. 0.29 parts of sulfamic acid were added to the obtained diazonium salt solution to remove excess nitrous acid, and a diazo component solution was prepared.

[0099] 59.1 parts of o-acetoacetaniside, 3.1 parts of p-acetoacetaniside, 30.7 parts of sodium hydroxide, and 400 parts of ion-exchanged water were mixed and stirred to completely dissolve the mixture, obtaining a liquid. The above liquid was added to an aqueous solution of 49.2 parts of acetic acid and 327 parts of ion-exchanged water, and the mixture was stirred to prepare a mixed coupler component slurry.

[0100] The mixed coupler component slurry was heated to 40°C using an oil bath, and the diazo component solution was added dropwise over 45 minutes while maintaining the internal temperature at 40°C. After stirring at 40°C for 30 minutes, the internal temperature was raised to 70°C and stirred for 20 minutes to complete the reaction. The reaction solution was allowed to cool to room temperature, and the reaction precipitate was filtered and taken out, and washed three times with 1,500 parts of ion-exchanged water to obtain a cake-like crude reaction product. The crude reaction product was added with 5,000 parts of ion-exchanged water to obtain a slurry, which was stirred for 1 hour, washed, and filtered. The filtrate was added with 2,500 parts of ethanol and washed in the same manner, and the obtained filtrate was dried to obtain 99.0 parts of a mixed coupling product 1 containing PY74 and Syn02 (yield 87%).

[0101] The results of analysis of mixed coupling product 1 by HPLC / MS are shown below. [HPLC / MS] (i) Peak (a): PY74 Measured value: MS(ES+) m / z 387.34(M+H) + MS(ES-)m / z 385.34(MH) - Calculated value: C 18 H 18 N 4 O 6 =386.12 (ii) Peak (b): Syn02 Measured value: MS(ES+) m / z 387.35(M+H) + MS(ES-)m / z 385.35(MH) - Calculated value: C 18 H 18 N 4 O 6 =386.12 (iii) Mass ratio PY74: 95.13% Syn02: 4.87% Mass ratio of Syn02 to PY74 (Syn02 / PY74): 0.051

[0102] (Mixed coupling product 2) A diazo component solution and a mixed coupler component slurry were prepared in the same manner as in the case of the mixed coupling product 1 described above, except that 3.1 parts of m-acetoacetanisidide were used instead of 3.1 parts of p-acetoacetanisidide. The mixed coupler component slurry was heated to 40°C using an oil bath, and the diazo component solution was added dropwise over 45 minutes while maintaining the internal temperature at 40°C. Next, a rosinamine acetic acid solution obtained by dissolving 1.36 parts of rosinamine in 7.22 parts of acetic acid was added. After stirring for 5 minutes, an aqueous sodium hydroxide solution was added to adjust the pH to 8.5, and the mixture was stirred for another 5 minutes. After adding acetic acid to adjust the pH to 7.0, the internal temperature was raised to 70°C and stirred for 20 minutes to complete the reaction. The reaction solution was allowed to cool to room temperature, and the reaction precipitate taken out by filtration was washed three times with 1,500 parts of ion-exchanged water to obtain a cake-like crude reaction product. The crude reactant was added with 5,000 parts of ion-exchanged water to obtain a slurry, which was stirred for 1 hour, washed, and filtered. The filtered product was added with 2,500 parts of ethanol and washed in the same manner, and the obtained filtered product was dried to obtain 101.1 parts of a rosin amine-treated mixed coupling product 2 containing PY74 and Syn01 (yield 88%).

[0103] The results of analysis of mixed coupling product 2 by HPLC / MS are shown below. [HPLC / MS] (i) Peak (a): PY74 Measured value: MS(ES+) m / z 387.34(M+H) + MS(ES-)m / z 385.35(MH) - Calculated value: C 18 H 18 N 4 O 6 =386.12 (ii) Peak (b): Syn01 Measured value: MS(ES+) m / z 387.35(M+H) + MS(ES-)m / z 385.35(MH) - Calculated value: C 18 H 18 N4 O 6 =386.12 (iii) Mass ratio PY74: 94.23% Syn01: 4.82% Rosin amine: 0.95% Mass ratio of Syn01 to PY74 (Syn01 / PY74): 0.051 Mass ratio of rosin amine to PY74 (rosin amine / PY74): 0.010

[0104] (Mixed coupling product 3) Instead of 3.1 parts of m-acetoacetanisidide, 3.1 parts of p-acetoacetanisidide was used. Except for this, the procedure was carried out in the same manner as in the case of the above-mentioned mixed coupling product 2 to obtain 99.3 parts of a rosin amine-treated mixed coupling product 3 containing PY74 and Syn02 (yield 86%).

[0105] The results of analysis of mixed coupling product 3 by HPLC / MS are shown below. [HPLC / MS] (i) Peak (a): PY74 Measured value: MS(ES+) m / z 387.33(M+H) + MS(ES-)m / z 385.34(MH) - Calculated value: C 18 H 18 N 4 O 6 =386.12 (ii) Peak (b): Syn02 Measured value: MS(ES+) m / z 387.34(M+H) + MS(ES-)m / z 385.35(MH) - Calculated value: C 18 H 18 N 4 O 6 =386.12 (iii) Mass ratio PY74: 94.20% Syn02: 4.89% Rosin amine: 0.91% Mass ratio of Syn02 to PY74 (Syn02 / PY74): 0.052 Mass ratio of rosin amine to PY74 (rosin amine / PY74): 0.010

[0106] <Preparation of Pigment Composition> (crude yellow pigment) Yellow pigment crude materials Y1 to Y10 of the types shown in Table 2 were prepared. The meanings of the abbreviations in Table 2 are as follows. PY74: CI Pigment Yellow 74 PY73: CI Pigment Yellow 73 PY3: CI Pigment Yellow 3 RA: Rosin amine HR: Hydrogenated rosin

[0107] TIFF2025078475000008.tif104170

[0108] (Pigment Compositions 1, 2, and 15) 500 parts of sodium chloride (trade name "Naclfo 1", manufactured by Naikai Salt Co., Ltd.) and 85 parts of diethylene glycol were added to 100 parts of the mixed coupling product of the type shown in Table 3. Then, the pigments were mixed and pulverized by a solvent salt milling method in which the mixture was kneaded at 30°C for 4 hours using a kneader (trade name "TX-2L", manufactured by Inoue Seisakusho Co., Ltd.) to obtain a kneaded product. The kneaded product obtained was thoroughly washed with ion-exchanged water, filtered and dried to obtain pigment compositions 1, 2, and 15.

[0109] (Pigment compositions 4, 5, 9-14, 16-21, and 23-25) Pigment compositions 4, 5, 9 to 14, 16 to 21, and 23 to 25 were obtained by the same solvent salt milling method as in the case of pigment compositions 1, 2, and 15, using the types and amounts of yellow pigment crude and pigment derivatives shown in Table 3. Note that for pigment composition 23, only the yellow pigment crude was used as the raw material without using the pigment derivative.

[0110] (Pigment Compositions 6 and 7) The yellow pigment crude and pigment derivative of the type and amount shown in Table 3 were mixed, and 1,000 parts of the solvent of the type shown in Table 3 were added to obtain a suspension, which was stirred at 25°C for 2 hours. The suspension was filtered to obtain a filtrate. The filtrate obtained was washed twice by adding 3,000 parts of ion-exchanged water and stirring for 30 minutes, and then pretreated by drying to obtain a pretreated pigment. Then, pigment compositions 6 and 7 were obtained in the same manner as in the above-mentioned pigment compositions 1, 2, and 15, except that the pretreated pigment obtained was used instead of the mixed coupling product. In Table 3, "NMP" means N-methylpyrrolidone, and "DMSO" means dimethyl sulfoxide.

[0111] (Pigment Compositions 3, 8, and 22) The raw materials shown in Table 3 in their types and amounts were placed in a mortar and thoroughly mixed to obtain pigment compositions 3, 8, and 22. That is, pigment compositions 3, 8, and 22 were prepared by subjecting the pigments to a micronizing treatment by a dry grinding method.

[0112] The properties of the resulting pigment composition are summarized in Table 3.

[0113] TIFF2025078475000009.tif186170

[0114] <Resin synthesis> (Resin 1) 200.0 parts of isopropanol was placed in a flask equipped with a stirrer, a nitrogen inlet tube, a reflux condenser, and a thermometer, and the temperature was raised to 85°C under a nitrogen atmosphere while stirring. A mixture of 60.0 parts of styrene, 20.0 parts of n-butyl acrylate, 20.0 parts of acrylic acid, and 5.0 parts of a polymerization initiator was added dropwise to the flask over a period of 2 hours while maintaining the system at 85°C. As the polymerization initiator, a solution in which 5.0 parts of "Percadox L-W75 (LS)" (dibenzoyl peroxide, manufactured by Kayaku Akzo, purity 75%) was dissolved in 10.0 parts of isopropanol was used. The system was kept at 85°C and stirred for 4 hours to synthesize resin 1. After adding potassium hydroxide 0.9 times (molar basis) the acid value of the resin and an appropriate amount of ion-exchanged water, isopropanol was removed under reduced pressure to obtain a liquid containing resin 1 with a resin content of 20.0%.

[0115] (Resin 2) A commercially available polymer dispersant (product name "Solsperse 17000", manufactured by Lubrizol Japan) was used as resin 2. The resin content in resin 2 was 100.0%.

[0116] <Preparation of pigment dispersion> (Pigment dispersions 1-21 and 23-26) The pigment composition, resin (liquid containing resin), and liquid medium were mixed in the types and amounts shown in Table 4, and dispersed at a processing pressure of 200 MPa using a homogenizer (product name "Starburst", manufactured by Sugino Machine). An appropriate amount of ion-exchanged water was then added to obtain pigment dispersions 1 to 21 and 23 to 26 with a pigment content (including pigment derivatives and rosins) of 15.0%.

[0117] (Pigment Dispersion 22) After the dispersion treatment, a pigment dispersion 22 having a pigment content (including pigment derivatives and rosins) of 15.0% was obtained in the same manner as in the above-mentioned pigment dispersions 1 to 21 and 23 to 26, except that an appropriate amount of isopropyl palmitate was added instead of the ion-exchanged water. In Table 4, "IPP" means isopropyl palmitate.

[0118] TIFF2025078475000010.tif197170

[0119] <Ink Preparation> Each ink was prepared by mixing the components (unit: parts) shown in Tables 5 to 7, thoroughly stirring, and then filtering under pressure with a microfilter (manufactured by Fujifilm) with a pore size of 2.5 μm. In Tables 5 to 7, "Acetylenol E100" is the product name of a nonionic surfactant manufactured by Kawaken Fine Chemicals. Also, "AF Solvent No. 4" is the product name of a non-polar organic solvent manufactured by ENEOS.

[0120] TIFF2025078475000011.tif148170

[0121] TIFF2025078475000012.tif147170

[0122] TIFF2025078475000013.tif138170

[0123] <Evaluation> Each ink obtained above was filled into an ink cartridge, and the ink was mounted on an inkjet recording device (trade name "PIXUS PRO-10S", manufactured by Canon) that ejects ink from a recording head by thermal energy. In this embodiment, the recording duty of a solid image recorded under the condition that 8 drops of 3.8 ng of ink are applied to a unit area of ​​1 / 600 inch x 1 / 600 inch is defined as 100%. Using the above inkjet recording device, 14 types of solid images were recorded on an A4-sized recording medium (photo paper, trade name "Canon Photo Paper Gloss Gold GL-101", manufactured by Canon) with the recording duty changed in 10% increments from 10 to 140%. After that, the images were dried at 25°C for 24 hours and used for the following evaluation. In the present invention, "A" and "B" were defined as acceptable levels and "C" was defined as unacceptable levels in the evaluation criteria for each of the following items. The evaluation results are shown in Table 8.

[0124] (Storage stability) The prepared ink was sealed and stored in a thermostatic chamber at 60° C. for one month. Using a nanoparticle size measuring device (product name "Nanotrac Wave", manufactured by MicrotracBEL), the particle size of the pigment in the ink (cumulative 50% particle size on a volume basis D 50 ) was measured in mono-disperse mode. The "particle size change rate (%) before and after storage" was calculated from the following formula (X), and the storage stability of the ink was evaluated according to the following evaluation criteria. Particle size change rate before and after storage (%) = {(d s -d i ) / d i}×100 ···(X) d s :D of pigment in ink after storage 50 d i : D of pigment in ink immediately after preparation 50 A: The change in particle size before and after storage was less than 5%. B: The rate of change in particle size before and after storage was 5% or more and less than 10%. C: The rate of change in particle size before and after storage was 10% or more.

[0125] (color stability) A fluorescence spectrodensitometer (product name "FD-7", manufactured by Konica Minolta) was used to measure the chromaticity a* of a solid image with a recording duty of 30%. The ink was sealed and left to stand in a thermostatic chamber at 60°C for one month. A solid image with a recording duty of 30% was recorded using the ink after storage in the same manner as above, and the chromaticity a* was measured. The "chromaticity change rate (%) before and after storage" was then calculated from the following formula (Y), and the color tone stability was evaluated according to the evaluation criteria shown below. Color change rate before and after storage (%) = {(a* s -a* i ) / a* i}×100 ··(Y) a* s : Chromaticity of a solid image recorded using the ink after storage a* i Chromaticity of a solid image recorded using the ink immediately after preparation A: The change in color before and after storage was less than 5%. B: The rate of change in color before and after storage was 5% or more and less than 10%. C: The rate of change in color before and after storage was 10% or more.

[0126] TIFF2025078475000014.tif110170

[0127] The disclosure of this embodiment includes the following configurations and methods. (Configuration 1) An image-recording composition comprising a pigment composition containing a yellow monoazo pigment and a compound represented by the following formula (1) or a compound represented by the following formula (2) which is different from the yellow monoazo pigment:

[0128] TIFF2025078475000015.tif43170

[0129] (Configuration 2) The image-recording composition according to Configuration 1, wherein the content (mass%) of the compound represented by Formula (1) or the compound represented by Formula (2) is 0.001 times or more and 0.100 times or less in mass ratio to the content (mass%) of the yellow monoazo pigment. (Configuration 3) The image recording composition according to configuration 1 or 2, wherein the pigment composition is a surface-treated product in which the particle surfaces are treated with rosins. (Configuration 4) The image recording composition according to Configuration 3, wherein the content (mass%) of the rosin is 0.001 to 0.050 times the content (mass%) of the yellow monoazo pigment in terms of a mass ratio. (Configuration 5) The image-recording composition according to any one of Configurations 1 to 4, wherein the yellow monoazo pigment is CI Pigment Yellow 74. (Configuration 6) The image-recording composition according to any one of Configurations 1 to 5, wherein the compound represented by Formula (1) or the compound represented by Formula (2) is physically adsorbed onto particle surfaces of the yellow monoazo pigment to form the pigment composition. (Configuration 7) The image-recording composition according to any one of Configurations 1 to 6, which is a water-based inkjet ink. (Method 1) A method for producing an image-recording composition containing a pigment composition including a yellow monoazo pigment and a compound represented by the following formula (1) or a compound represented by the following formula (2) different from the yellow monoazo pigment, the method comprising the steps of: coupling a diazo component (c1) obtained by converting 2-methoxy-4-nitroaniline into a diazonium salt with a coupler component mixture (c2) containing a coupler component (a2) and a coupler component (b2) that are acetoacetanilide derivatives; A method for producing an image-recording composition, comprising: simultaneously synthesizing the yellow monoazo pigment and a compound represented by the following formula (1) or a compound represented by the following formula (2) to obtain a crude product of the pigment composition:

[0130] TIFF2025078475000016.tif43170

[0131] (Method 2) The method for producing an image-recording composition according to Method 1, further comprising the step of subjecting the crude pigment composition to solvent salt milling to obtain the pigment composition. (Method 3) A method for producing an image-recording composition containing a pigment composition including a yellow monoazo pigment and a compound represented by the following formula (1) or a compound represented by the following formula (2) different from the yellow monoazo pigment, the method comprising the steps of: a process for producing an image-recording composition, the process comprising subjecting a pre-treatment mixture containing the crude yellow monoazo pigment and a compound represented by the following formula (1) or a compound represented by the following formula (2) to solvent salt milling to obtain the pigment composition.

[0132] TIFF2025078475000017.tif43170

[0133] (Method 4) further comprising a step of dissolving at least a part of a crude mixture containing the crude yellow monoazo pigment, and the crude compound represented by formula (1) or the crude compound represented by formula (2) in an organic solvent; removing at least a part of the organic solvent from the crude mixture and physically adsorbing the compound represented by formula (1) or the compound represented by formula (2) onto particle surfaces of the yellow monoazo pigment to obtain the pretreated mixture; Method 3 for producing the image-recording composition according to the present invention, comprising the steps of:

Claims

1. 1. An image-recording composition comprising a pigment composition containing a yellow monoazo pigment and a compound represented by the following formula (1) or a compound represented by the following formula (2) which is different from the yellow monoazo pigment:

2. 2. The image-recording composition according to claim 1, wherein the content (mass%) of the compound represented by formula (1) or the compound represented by formula (2) is 0.001 times or more and 0.100 times or less in mass ratio to the content (mass%) of the yellow monoazo pigment.

3. 2. The image recording composition according to claim 1, wherein the pigment composition is a surface-treated product in which the particle surfaces are treated with a rosin.

4. 4. The image recording composition according to claim 3, wherein the content (mass %) of the rosin is 0.001 to 0.050 times the content (mass %) of the yellow monoazo pigment in terms of a mass ratio.

5. 2. The image-recording composition according to claim 1, wherein the yellow monoazo pigment is C.I. Pigment Yellow 74.

6. 2. The image-recording composition according to claim 1, wherein the compound represented by formula (1) or the compound represented by formula (2) is physically adsorbed onto particle surfaces of the yellow monoazo pigment to form the pigment composition.

7. 2. The image recording composition according to claim 1, which is a water-based inkjet ink.

8. A method for producing an image-recording composition containing a pigment composition including a yellow monoazo pigment and a compound represented by the following formula (1) or a compound represented by the following formula (2) different from the yellow monoazo pigment, comprising: coupling a diazo component (c1) obtained by converting 2-methoxy-4-nitroaniline into a diazonium salt with a coupler component mixture (c2) containing a coupler component (a2) and a coupler component (b2) that are acetoacetanilide derivatives; A method for producing an image-recording composition, comprising: simultaneously synthesizing the yellow monoazo pigment, and a compound represented by the following formula (1) or a compound represented by the following formula (2) to obtain a crude product of the pigment composition:

9. The method for producing an image-recording composition according to claim 8 , further comprising a step of subjecting the crude pigment composition to solvent salt milling to obtain the pigment composition.

10. A method for producing an image-recording composition containing a pigment composition including a yellow monoazo pigment and a compound represented by the following formula (1) or a compound represented by the following formula (2) different from the yellow monoazo pigment, comprising: a pretreatment mixture containing the crude yellow monoazo pigment and a compound represented by the following formula (1) or a compound represented by the following formula (2), thereby obtaining the pigment composition.

11. Furthermore, a step of dissolving at least a part of a crude mixture containing the crude yellow monoazo pigment and the crude compound represented by formula (1) or the crude compound represented by formula (2) in an organic solvent; removing at least a portion of the organic solvent from the crude mixture and physically adsorbing the compound represented by formula (1) or the compound represented by formula (2) onto particle surfaces of the yellow monoazo pigment to obtain the pre-treated mixture; The method for producing the image-recording composition according to claim 10, comprising the steps of:

Images