Method for producing resin-treated pigment, method for producing pigment dispersion, method for producing ultraviolet curable inkjet ink, and method for producing printed film

Abstract

To provide a resin-treated pigment which enables production of a pigment dispersion liquid useful as a raw material for preparing ultraviolet curable inkjet ink that has low viscosity and excellent storage stability, in which a pigment is finely dispersed, even if a monomer having a comparatively small SP value is contained as a liquid medium.SOLUTION: A resin-treated pigment is obtained by adding a resin A having a constitutional unit (ii) represented by general formula (3) and having a quaternary chloride rate of 20 to 35 mol%, to a mixture containing an organic cyan pigment and a pigment derivative represented by general formula (1), and precipitating a resin B in which at least a part of the constitutional unit (ii) is converted into a constitutional unit (iv) represented by general formula (4). In the formulae, M is Na or the like, E is an organic pigment skeleton, C is O or NH, D is an ethylene group or the like, and X is Cl or the like.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a resin-treated pigment, a pigment dispersion, an ultraviolet-curable inkjet ink, and a printed film. [Background technology]

[0002] The inkjet printing method does not require a plate and is capable of printing images on demand by data output from a personal computer. In the inkjet printing method, aqueous inkjet ink, solvent-based inkjet ink, ultraviolet-curable inkjet ink, etc. are used. When a solvent-based inkjet ink is used, there is a concern that the organic solvent released from the ink may cause a burden on the environment. For this reason, aqueous inkjet ink using water as a solvent and ultraviolet-curable inkjet ink that does not substantially contain volatile components and all components form a coating film are widely used in industrial applications.

[0003] In particular, printing methods using ultraviolet-curable inkjet (hereinafter also referred to as "UVIJ") inks, which do not require a drying process and can produce images with excellent durability, are being considered for industrial applications such as sign displays, packaging, and printing on plastic containers. Printing methods using UVIJ inks are shifting from conventional single-pass printing to high-speed printing in which ink is ejected from a line head at one time to print large-area images at once. There is a demand for UVIJ inks that can handle such high-speed printing.

[0004] UVIJ ink is prepared by blending a pigment dispersion liquid in which an ultraviolet-curable monomer is used as a liquid medium, an oligomer, a photoinitiator, and the like. The hues of UVIJ ink include the three primary colors of cyan, magenta, and yellow, as well as black and white, and complementary colors such as green, orange, and blue. A pigment dispersion liquid containing a pigment of each color is used to prepare UVIJ ink of each color. In order to prepare an ink that can be stably ejected from a recording head, in which the pigment is finely dispersed, and has a low viscosity, a pigment dispersion liquid in which the pigment is finely dispersed, in which the pigment is less likely to aggregate even after storage, and in which the viscosity is stable is required. Various pigment dispersion liquids having such characteristics have been studied (Patent Documents 1 to 6). An ink in which the pigment is finely dispersed, has a low viscosity, and in which the pigment dispersion state is stably maintained has good ejection properties from a recording head, can record images with clear dots, and can also be used for the above-mentioned high-speed printing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2006-282758 A [Patent Document 2] JP 2004-2528 A [Patent Document 3] JP 2014-145053 A [Patent Document 4] JP 2001-288386 A [Patent Document 5] JP 2003-321628 A [Patent Document 6] JP 2008-285677 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, when attempting to finely disperse a pigment, the pigment is more likely to aggregate due to an increase in surface energy. As a result, problems such as an increase in the viscosity of the pigment dispersion during storage and an increase in the particle size of the pigment occur, resulting in problems such as a decrease in the storage stability of the pigment dispersion. In addition, in order to achieve low viscosity and fine dispersion of the pigment in a pigment dispersion containing an ultraviolet-curable monomer, a pigment, and a pigment dispersant, a long dispersion process is required, which leads to problems such as increased costs and energy consumption.

[0007] Furthermore, the type of UV-curable monomer is selected depending on the substrate to be coated. Therefore, it is necessary to prepare a pigment dispersion liquid according to the type of UV-curable monomer, and there are cases where a large number of types of pigment dispersion liquids need to be prepared. In addition, there are various regulations when transporting pigment dispersion liquids containing various monomers, and there are also issues such as increased costs and energy consumption.

[0008] In recent years, the use of biomass in inkjet inks has been promoted. In particular, the use of biomass-derived monomers as monomers to be blended into UVIJ inks and the like is one of the useful methods for improving the biomass content of inks. However, for example, isobornyl acrylate (IBXA), a monofunctional monomer derived from biomass, has a relatively small SP value (SP value: 8.34). When a monomer with such a small SP value is used, it may take a long time to disperse the pigment compared to when a monomer with a large SP value is used. Furthermore, it may be difficult to improve the color development of an image printed with UVIJ ink prepared using a pigment dispersion containing a monomer with a small SP value.

[0009] The present invention has been made in consideration of the problems associated with the conventional techniques, and an object of the present invention is to provide a resin-treated pigment that can be used to produce a pigment dispersion that is useful as a raw material for preparing an ultraviolet-curable inkjet ink, in which the pigment is finely dispersed with low viscosity and has excellent storage stability, even when the liquid medium contains a monomer with a relatively small SP value.

[0010] Another object of the present invention is to provide a pigment dispersion which is useful as a raw material for preparing an ultraviolet-curable inkjet ink, which uses the above-mentioned resin-treated pigment and has a low viscosity, finely dispersed pigment, and excellent storage stability, even when the liquid medium contains a monomer having a relatively small SP value.

[0011] Another object of the present invention is to provide an ultraviolet-curable inkjet ink that uses the above-mentioned pigment dispersion, in which the pigment is finely dispersed at a low viscosity, has excellent storage stability, and is capable of forming a printed film that is excellent in color development, adhesion to a substrate, etc. Another object of the present invention is to provide a printed film that is formed using the above-mentioned ultraviolet-curable inkjet ink, and that is excellent in color development, adhesion to a substrate, etc. [Means for solving the problem]

[0012] That is, according to the present invention, there is provided the following resin-treated pigment. [1] A resin-treated pigment obtained by adding 20 to 70 parts by mass of a resin A that is liquid at room temperature, the resin A having 40 to 80 mass% of structural units (i) represented by general formula (2) below, 3 to 30 mass% of structural units (ii) represented by general formula (3) below, and 1 to 57 mass% of other structural units (iii), a number average molecular weight of 9,000 to 30,000, and a quaternary chloride ratio of 20 to 35 mol% to a mixture containing 100 parts by mass of a cyan organic pigment, 5 to 20 parts by mass of a dye derivative represented by general formula (1) below, and water, to precipitate a resin B in which at least a portion of the structural units (ii) have been converted to structural units (iv) represented by general formula (4) below.

[0013] TIFF2025057778000001.tif24170 (In the general formula (1), M represents a lithium atom, a sodium atom, or a potassium atom, and E represents an organic dye skeleton.)

[0014] TIFF2025057778000002.tif34170 (In the above general formula (2), R represents a hydrogen atom or a methyl group, and R 1 represents a hydrogen atom or a methyl group, R 2 represents a hydrogen atom, a methyl group, or a butyl group, A represents O or NH, B represents an ethylene group or a methylethylene group, X represents O, NHCOO, or NHCONH, n is a number from 20 to 100 representing the average number of repeating units, and p represents an arbitrary number of repeating units.

[0015] TIFF2025057778000003.tif37170 (wherein R 3 represents a hydrogen atom or a methyl group, R 4 each independently represents a methyl group, an ethyl group, or a propyl group; R 5 represents a methyl group or a benzyl group, C represents O or NH, D represents an ethylene group or a propylene group, X represents a chlorine atom, a bromine atom, or an iodine atom, and q represents any number of repetitions.

[0016] TIFF2025057778000004.tif39170 (In the above general formula (4), R 3 represents a hydrogen atom or a methyl group, R 4 each independently represents a methyl group, an ethyl group, or a propyl group; R 5 represents a methyl group or a benzyl group, C represents O or NH, D represents an ethylene group or a propylene group, E represents an organic dye skeleton, and r represents any number of repetitions.

[0017] [2] The resin-treated pigment according to [1], wherein the organic dye skeleton represented by E in the general formula (1) is a phthalocyanine dye skeleton. [3] The resin-treated pigment according to [1] or [2], wherein the content of the resin B per 100 parts by mass of the organic pigment is 30 to 70 parts by mass. [4] The resin-treated pigment according to any one of [1] to [3] above, wherein the structural unit (iii) is a structural unit derived from α-methylstyrene. [5] The resin-treated pigment according to [4], wherein the structural unit (iii) comprises a structural unit (iii-1) represented by the following general formula (5):

[0018] TIFF2025057778000005.tif34170 (wherein R 3 represents a hydrogen atom or a methyl group, C represents O or NH, D represents an ethylene group or a propylene group, R 4 each independently represents a methyl group, an ethyl group, or a propyl group, and s represents an arbitrary number of repetitions.

[0019] According to the present invention, there is also provided a pigment dispersion liquid as shown below. [6] A pigment dispersion comprising a liquid medium and the resin-treated pigment according to any one of [1] to [5] above dispersed in the liquid medium. [7] The pigment dispersion according to [6], wherein the liquid medium is an ultraviolet-curable monomer.

[0020] Furthermore, according to the present invention, there are provided the following ultraviolet-curable ink-jet inks and printed films. [8] An ultraviolet-curable inkjet ink containing the pigment dispersion liquid described in [7] above. [9] A printed film which is a cured product of the ultraviolet-curable inkjet ink described in [8] above. Effect of the Invention

[0021] According to the present invention, it is possible to provide a resin-treated pigment capable of producing a pigment dispersion liquid useful as a raw material for preparing an ultraviolet-curable inkjet ink, which has low viscosity, finely dispersed pigments, and excellent storage stability, even when the liquid medium contains a monomer having a relatively small SP value.

[0022] Furthermore, according to the present invention, even when the liquid medium contains a monomer having a relatively small SP value, it is possible to provide a pigment dispersion liquid which is useful as a raw material for preparing an ultraviolet-curable inkjet ink, which has a low viscosity and in which the pigment is finely dispersed, and which has excellent storage stability.

[0023] Furthermore, according to the present invention, it is possible to provide an ultraviolet-curable inkjet ink that uses the above-mentioned pigment dispersion, in which the pigment is finely dispersed with low viscosity, has excellent storage stability, and is capable of forming a printed film that is excellent in color development, adhesion to a substrate, etc. Furthermore, according to the present invention, it is possible to provide a printed film that is formed using the above-mentioned ultraviolet-curable inkjet ink, and that is excellent in color development, adhesion to a substrate, etc. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] <Resin-treated pigment> Hereinafter, the embodiment of the present invention will be described, but the present invention is not limited to the following embodiment. One embodiment of the resin-treated pigment of the present invention is produced by the production method shown below. That is, the production method of the resin-treated pigment includes a step of adding 20 to 70 parts by mass of resin A to a mixture containing 100 parts by mass of a cyan organic pigment, 5 to 20 parts by mass of a dye derivative represented by the following general formula (1), and water. Resin A is a resin that is liquid under room temperature conditions, has a number average molecular weight of 9,000 to 30,000, a quaternary chloride ratio of 20 to 35 mol%, and contains 40 to 80% by mass of a structural unit (i) represented by the following general formula (2), 3 to 30% by mass of a structural unit (ii) represented by the following general formula (3), and 1 to 57% by mass of other structural units (iii). In the above step, resin A is added to a mixture containing an organic pigment, a dye derivative, and water, thereby precipitating resin B in which at least a part of the structural unit (ii) in resin A is converted to a structural unit (iv) represented by the following general formula (4), thereby obtaining a resin-treated pigment.

[0025] TIFF2025057778000006.tif24170 (In the general formula (1), M represents a lithium atom, a sodium atom, or a potassium atom, and E represents an organic dye skeleton.)

[0026] TIFF2025057778000007.tif34170 (In the above general formula (2), R represents a hydrogen atom or a methyl group, and R 1 represents a hydrogen atom or a methyl group, R 2 represents a hydrogen atom, a methyl group, or a butyl group, A represents O or NH, B represents an ethylene group or a methylethylene group, X represents O, NHCOO, or NHCONH, n is a number from 20 to 100 representing the average number of repeating units, and p represents an arbitrary number of repeating units.

[0027] TIFF2025057778000008.tif37170 (In the above general formula (3), R 3 represents a hydrogen atom or a methyl group, R 4 each independently represents a methyl group, an ethyl group, or a propyl group; R 5 represents a methyl group or a benzyl group, C represents O or NH, D represents an ethylene group or a propylene group, X represents a chlorine atom, a bromine atom, or an iodine atom, and q represents any number of repetitions.

[0028] TIFF2025057778000009.tif39170 (In the above general formula (4), R 3 represents a hydrogen atom or a methyl group, R 4 each independently represents a methyl group, an ethyl group, or a propyl group; R 5 represents a methyl group or a benzyl group, C represents O or NH, D represents an ethylene group or a propylene group, E represents an organic dye skeleton, and r represents any number of repetitions.

[0029] (Organic pigments) As the organic pigment, a cyan organic pigment is used. As the cyan organic pigment, an organic pigment used in inkjet ink is preferable, and examples of the organic pigment include pigment blue 15:3, 15:4, 15:6, and 60 in terms of color index name.

[0030] The organic pigment is usually particulate. The number average particle diameter (primary particle diameter) of the particulate organic pigment is preferably 150 nm or less. By using an organic pigment having a number average particle diameter of 150 nm or less, the optical density, saturation, color development, and print quality of the recorded image can be improved, and clogging of the recording head can be prevented, allowing for good ejection. The number average particle diameter of the organic pigment can be measured, for example, using an electron microscope or a light scattering particle size distribution meter.

[0031] (Pigment Derivatives) The dye derivative is a compound represented by the following general formula (1) in which an anion of a sulfonic acid group is bonded to an organic dye skeleton. In general formula (1), it is preferable that the organic dye skeleton represented by E has a structure equivalent to or similar to that of an organic pigment, since it is easily and strongly adsorbed to the organic pigment. Resin B having a structural unit (iv) having a counter ion derived from the dye derivative is insoluble in liquid media such as water and organic solvents. Then, it is adsorbed to the organic pigment to introduce an anion of a sulfonic acid group, and is difficult to be detached from the adsorbed organic pigment, so that the organic pigment can be stably and finely dispersed in the liquid medium.

[0032] TIFF2025057778000010.tif24170 (In the general formula (1), M represents a lithium atom, a sodium atom, or a potassium atom, and E represents an organic dye skeleton.)

[0033] In the general formula (1), the organic dye skeleton represented by E is preferably a phthalocyanine dye skeleton. In the general formula (1), M is a lithium atom, a sodium atom, or a potassium atom, and is preferably a sodium atom or a potassium atom. When M is a lithium atom in the general formula (1), dissociation in water may be difficult. One sulfonic acid anion may be bonded to the organic dye skeleton represented by E, and two or more may be bonded.

[0034] Examples of the dye derivative having a phthalocyanine dye skeleton include compounds represented by the following formulas (A) and (B).

[0035] TIFF2025057778000011.tif63170

[0036] TIFF2025057778000012.tif61170

[0037] (Resin A) Resin A has a structural unit (i) represented by the following general formula (2), a structural unit (ii) represented by the following general formula (3), and another structural unit (iii).

[0038] TIFF2025057778000013.tif34170 (In the general formula (2), R represents a hydrogen atom or a methyl group, and R 1 represents a hydrogen atom or a methyl group, R 2 represents a hydrogen atom, a methyl group, or a butyl group, A represents O or NH, B represents an ethylene group or a methylethylene group, X represents O, NHCOO, or NHCONH, n is a number from 20 to 100 representing the average number of repeating units, and p represents an arbitrary number of repeating units.

[0039] TIFF2025057778000014.tif37170 (In the above general formula (3), R 3 represents a hydrogen atom or a methyl group, R 4 each independently represents a methyl group, an ethyl group, or a propyl group; R 5 represents a methyl group or a benzyl group, C represents O or NH, D represents an ethylene group or a propylene group, X represents a chlorine atom, a bromine atom, or an iodine atom, and q represents any number of repetitions.

[0040] The structural unit (i) is a structural unit derived from a macromonomer having a polyalkylene glycol chain. The structural unit (i) dissolves in a dispersion medium such as an ultraviolet-curable monomer and acts as a steric hindrance between particles, causing repulsion, and the organic pigment can be stably dispersed in the dispersion medium for a long period of time. In addition, by containing a large amount of polyalkylene glycol chains, the resin A can be made liquid under room temperature conditions.

[0041] In general formula (2), the average number of repeating units represented by n is a number from 20 to 100, and therefore the molecular weight of the macromonomer is within the range of 880 to 5,800.

[0042] Examples of the macromonomer constituting the structural unit (i) include polyethylene glycol mono(meth)acrylate, polyethylene glycol monomethyl mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, polyethylene glycol polypropylene glycol mono(meth)acrylate, polyethylene glycol polypropylene glycol monobutyl(meth)acrylate, a reaction product of (meth)acryloyloxyethyl isocyanate with polyethylene glycol monomethyl ether, polyethylene glycol polypropylene glycol monobutyl ether, etc., a reaction product of (meth)acryloyloxyethyl isocyanate with polyethylene glycol monomethyl ether monoamine, polyethylene glycol polypropylene glycol monomethyl ether monoamine, a reaction product of (meth)acrylic acid, (meth)acrylic acid chloride, (meth)acrylic acid anhydride with polyethylene glycol monomethyl ether monoamine, polyethylene glycol polypropylene glycol monomethyl ether monoamine, etc. Among them, water-insoluble monomers are preferred, and macromonomers containing 50 mol% or more of polypropylene glycol in the glycol chain are preferred, and monomers containing 70 mol% or more are more preferred.

[0043] The structural unit (ii) is a monomer having a quaternary ammonium base with a chlorine, bromine, or iodine anion as a counter ion. The structural unit (ii) makes the resin A soluble in water. When the dye derivative represented by the general formula (1) and the resin A are mixed in water, an anion exchange reaction occurs, and the salt formed by the alkali metal ion and the halide ion is eliminated, and the counter ion of the quaternary ammonium base in the resin A becomes the anion of the sulfonic acid group of the dye derivative. This produces a resin B in which at least a part of the structural unit (ii) is converted to the structural unit (iv) represented by the general formula (4).

[0044] With the anions of the sulfonic acid groups in the dye derivative adsorbed to the organic pigment, resin A is converted to resin B, and the converted resin B is adsorbed to at least a portion of the surface of the organic pigment, resulting in a surface treatment of the organic pigment. Resin A, which has an affinity for and is soluble in water due to the structure of structural unit (ii), becomes insoluble in water as the sulfonic acid ions of the dye derivative become counter ions from the halide ions, and precipitates on the pigment surface while undergoing desalting and ion exchange. The dispersibility of the organic pigment is then maintained in a good state for a long period of time due to the solubility and steric repulsion of structural unit (i).

[0045] Examples of monomers constituting the structural unit (ii) include (meth)acryloyloxyethyl trimethylammonium chloride, (meth)acryloyloxyethyl diethylmethylammonium chloride, (meth)acryloyloxyethyl benzyl dimethyl chloride, (meth)acryloyloxyethyl benzyl diethyl chloride, (meth)acryloyloxyethyl trimethylammonium bromide, (meth)acryloyloxyethyl diethylmethylammonium bromide, (meth)acryloyloxyethyl benzyl dimethyl bromide, (meth)acryloyloxyethyl benzyl diethyl bromide, (meth)acryloyloxyethyl trimethylammonium iod ... Examples of the acryloyloxyethyl diethylmethyl ammonium iodide include (meth)acryloyloxyethyl benzyl dimethyl iodide, (meth)acryloyloxyethyl benzyl diethyl iodide, (meth)acryloylaminopropyl trimethyl ammonium chloride, (meth)acryloylaminopropyl benzyl trimethyl ammonium chloride, (meth)acryloylaminopropyl diethylmethyl ammonium chloride, (meth)acryloylaminopropyl benzyl diethyl chloride, (meth)acryloylaminopropyl dibutyl methyl chloride, and (meth)acryloylaminopropyl benzyl dibutyl ammonium chloride.

[0046] The other structural unit (iii) is a structural unit that can be linked to the structural units (i) and (ii). As the monomer that constitutes the structural unit (iii), a conventionally known monomer that can undergo radical polymerization can be used. As the monomer that constitutes the structural unit (iii), (meth)acrylic acid-based monomers such as (meth)acrylic acid and (meth)acrylate; vinyl monomers such as styrene, vinyl toluene, vinyl pyridine, vinyl caprolactone, vinyl imidazole, α-methyl styrene, and vinyl acetate; and the like can be mentioned. Among them, α-methyl styrene is preferred because it is easy to adjust the molecular weight and control the polymerization.

[0047] The structural unit (iii) preferably contains a structural unit (iii-1) represented by the following general formula (5).

[0048] TIFF2025057778000015.tif34170 (In the above general formula (5), R 3 represents a hydrogen atom or a methyl group, C represents O or NH, D represents an ethylene group or a propylene group, R 4 each independently represents a methyl group, an ethyl group, or a propyl group, and s represents an arbitrary number of repetitions.

[0049] Examples of monomers that constitute the structural unit (iii-1) include dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylamide, diethylaminoethylpropyl (meth)acrylamide, and dibutylaminopropyl (meth)acrylamide.

[0050] In the resin A, the proportion of the structural unit (i) is 40 to 80 mass%, preferably 50 to 70 mass%, the proportion of the structural unit (ii) is 3 to 30 mass%, preferably 5 to 20 mass%, and the proportion of the structural unit (iii) is 1 to 57 mass%. The total of the structural units (i) to (iii) is 100 mass%. If the proportion of the structural unit (i) is less than 40 mass%, the steric hindrance is insufficient, and the dispersibility of the organic pigment decreases. On the other hand, if the proportion of the structural unit (i) is more than 80 mass%, the macromonomer has a high molecular weight, so the polymerizable group at the end becomes diluted and is likely to remain without being polymerized.

[0051] If the ratio of the structural unit (ii) is less than 3% by mass, the amount of the dye derivative bonded decreases, and the adsorption portion of the organic pigment decreases. As a result, the resin B is detached from the organic pigment during dispersion or storage, and the dispersion stability decreases. On the other hand, if the ratio of the structural unit (ii) is more than 30% by mass, the amount of the dye derivative bonded increases, and the pigment dispersibility decreases or the pigment aggregates. In addition, since a large amount of the dye derivative is introduced, the hue of the dye derivative is easily expressed.

[0052] The number average molecular weight of resin A is 9,000 to 30,000, preferably 12,000 to 24,000. In this specification, "number average molecular weight (Mn)" means the number average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC). If the number average molecular weight of resin A is less than 9,000, the dispersibility of the pigment may decrease, and the pigment dispersion may thicken or the pigment may settle. On the other hand, if the number average molecular weight of resin A is more than 30,000, the polymerization time may become longer or the process may become complicated in order to obtain a high molecular weight, and the viscosity of the pigment dispersion may become excessively high.

[0053] The quaternary chloride ratio of resin A is 20 to 35 mol%. By using resin A having a quaternary chloride ratio in the range of 20 to 35 mol%, a resin-treated pigment can be obtained that has low viscosity, finely dispersed pigment, and excellent storage stability, and can be used to produce a pigment dispersion useful as a raw material for preparing ultraviolet-curable inkjet ink. Resin A is produced, for example, by reacting a precursor of resin A having an amino group with an alkylating agent such as an alkyl halide to alkylate a portion of the amino group to form a quaternary ammonium salt. In this specification, the "quaternary chloride ratio of resin A" is a physical property value that means the ratio (mol%) of amino groups (quaternary ammonium salt group) that have been converted to a quaternary ammonium salt among the amino groups in the precursor of resin A.

[0054] Resin A is a resin that is liquid at room temperature (25°C). If a pigment is treated with a solid resin at room temperature to produce a dry powder, the solid resin must be dissolved in the liquid medium when dispersing it in the liquid medium, which takes time to disperse and can result in the resin not being completely dissolved and forming "lumps." In contrast, if Resin A, which is liquid at room temperature, is used, the resin quickly becomes compatible with the liquid medium, making it easy to obtain the desired resin-treated pigment.

[0055] Resin A can be synthesized by a conventionally known method. For example, it can be synthesized by a conventionally known radical polymerization method; a polymerization method that adjusts the molecular weight using a chain transfer agent such as thiol; a living radical polymerization method that can make the molecular weight of the main chain more uniform and can form an AB block copolymer by an addition method, specifically, an atom transfer radical polymerization method (ATRP method), a reversible addition-fragmentation chain transfer polymerization method (RAFT method), a nitroxide method (NMP method), an organotellurium method (TERP method), an iodine transfer polymerization method (ITP method), a reversible transfer catalyst polymerization method (RTCP method), a reversible catalyst-mediated polymerization method (RCMP method), and other living radical polymerization methods.

[0056] The polymerization may be either thermal polymerization or photopolymerization, and an azo-based radical generator, a peroxide-based radical generator, a photosensitizer, or the like may be added to the polymerization reaction system. The polymerization form may be any of solventless, solution polymerization, and emulsion polymerization, among which solution polymerization is preferred. In the manufacturing method of the present invention, a water-soluble organic solvent can be used when mixing the organic pigment, the dye derivative, and the resin A in water. Therefore, since the resin A obtained by the polymerization reaction can be used as it is without isolation, it is preferable to synthesize the resin A by solution polymerization in a water-soluble organic solvent. Examples of the water-soluble organic solvent include lower alcohols, polyhydric alcohols, glycols, glycol ethers, glycol esters, amides, sulfoxides, and ureas. The resin A obtained by the polymerization reaction may be isolated.

[0057] (Method of manufacturing resin-treated pigment) 20 to 70 parts by mass of resin A is added to a mixture containing 100 parts by mass of organic pigment, 5 to 20 parts by mass of dye derivative, and water, and mixed. As a result, the counter ion (X - ) and the cation in the dye derivative (M + ) is eliminated (desalted), and at least a portion of the structural unit (ii) is converted to the structural unit (iv) represented by the following general formula (4) by ion exchange to produce a resin B. Since the produced resin B is substantially insoluble in water, it is believed to precipitate and be adsorbed and deposited on at least a portion of the surface of the pigment. This makes it possible to obtain the desired resin-treated pigment in which the resin B is adsorbed and deposited on at least a portion of the surface of the pigment.

[0058] TIFF2025057778000016.tif39170 (In the above general formula (4), R 3 represents a hydrogen atom or a methyl group, R 4 each independently represents a methyl group, an ethyl group, or a propyl group; R 5 represents a methyl group or a benzyl group, C represents O or NH, D represents an ethylene group or a propylene group, E represents an organic dye skeleton, and r represents any number of repetitions.

[0059] The mixture containing the organic pigment, the dye derivative, and water may further contain a water-soluble organic solvent, if necessary. Examples of the water-soluble organic solvent include alcohols such as methanol, ethanol, and isopropanol; glycols such as ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, diethylene glycol butyl ether, and triethylene glycol dimethyl ether; glycerin; amide-based solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; urea-based solvents such as tetramethylurea; and carbonate-based solvents such as ethylene carbonate.

[0060] It is preferable that the resin B is uniformly adsorbed and deposited on the surface of the primary particles of the organic pigment. For this reason, the pigment used in preparing the mixture may be a dry powder, but is preferably in the form of a water paste. In the case of a water paste, since it is not dried, even if the organic pigment forms secondary particles, the cohesive force is weak, and it can be easily made into fine primary particles by stirring. The amount of the organic pigment in the mixture is preferably 1 to 10% by mass.

[0061] The dye derivative may be pre-adsorbed on the surface of the organic pigment. The sulfonic acid group in the dye derivative may be a free acid that is not neutralized, but it is preferable to add an aqueous solution of an alkali metal hydroxide or the like to form a salt before adding the resin A. It is preferable to thoroughly mix and stir a mixture (aqueous slurry) containing the organic pigment, the dye derivative, and water to finely disperse the organic pigment particles.

[0062] The liquid property of the mixture when resin A is added is preferably neutral to alkaline, and more preferably in the range of pH 6.5 to 9.5. If the liquid property of the mixture is acidic, resin B may be difficult to form (precipitate). In addition, when resin A has an amino group, the amino group is easily ionized, so resin B may be difficult to precipitate and may be difficult to filter during post-treatment. On the other hand, if the liquid property of the mixture is strongly alkaline (for example, pH 9.5 or more), resin B may be difficult to precipitate in water. In addition, when resin A has an acidic group, the acidic group is easily ionized, so resin B may be difficult to precipitate and may be difficult to filter during post-treatment. After resin A is added to the mixture to precipitate resin B, it is recommended to heat the mixture to preferably 80°C or less, more preferably 60°C or less, and then filter it in order to make it easier to filter.

[0063] The mixture is filtered to obtain a solid content, which is then washed, and dried and pulverized as necessary to obtain the desired resin-treated pigment. The temperature during drying is preferably 150°C or lower, and more preferably 110°C or lower. When pulverizing the solid content, if an attempt is made to pulverize too finely, the particles may be easily fused together due to the heat during pulverization. Even a coarse particle size such as 100 mesh pass can be used sufficiently.

[0064] The amount of the dye derivative relative to 100 parts of the organic pigment is 5 to 20 parts by mass, preferably 6 to 15 parts by mass, and more preferably 6.5 to 10 parts by mass. If it is less than 5 parts by mass, the amount of the dye derivative is so small that the resin B is easily detached from the particle surface of the organic pigment, and the dispersion stability decreases. On the other hand, if it exceeds 20 parts by mass, the hue of the dye derivative may affect the hue of the organic pigment, and the viscosity of the dispersion may become excessively high.

[0065] The amount of resin A added is 20 to 70 parts by mass, preferably 20 to 60 parts by mass, more preferably 25 to 45 parts by mass, and particularly preferably 30 to 45 parts by mass, based on 100 parts by mass of the organic pigment. If the amount is less than 20 parts by mass, the resin content is insufficient, and the dispersion stability decreases. On the other hand, if the amount exceeds 70 parts by mass, the viscosity of the dispersion may become excessively high.

[0066] The amount of resin A added to the mixture (addition amount) is preferably an amount in which the amount of the quaternary ammonium salt in general formula (3) is 1.45 to 1.80 molar equivalents relative to the amount of sulfonate ions in general formula (1), and more preferably an amount in which the amount is 1.50 to 1.70 molar equivalents. If the amount of the quaternary ammonium salt is too small, the amount of the salt that is eliminated is small, and the amount of the resin B that precipitates may be insufficient. For this reason, it may be difficult to sufficiently cover the organic pigment, and the viscosity of the pigment dispersion obtained by dispersing in a monomer with a small SP value may become excessively high or aggregates may be generated. On the other hand, if the amount of the quaternary ammonium salt is too large, the viscosity of the pigment dispersion obtained may become excessively high or filtration may become difficult due to the influence of the excess quaternary ammonium salt that remains.

[0067] (Resin B) Resin B preferably contains 35 to 70 mass % of the structural unit (i) represented by the following general formula (2), other structural units (iii), and 10 to 50 mass % of the structural unit (iv) represented by the following general formula (4).

[0068] TIFF2025057778000017.tif34170 (In the above general formula (2), R represents a hydrogen atom or a methyl group, and R 1 represents a hydrogen atom or a methyl group, R 2 represents a hydrogen atom, a methyl group, or a butyl group, A represents O or NH, B represents an ethylene group or a methylethylene group, X represents O, NHCOO, or NHCONH, n is a number from 20 to 100 representing the average number of repeating units, and p represents an arbitrary number of repeating units.

[0069] TIFF2025057778000018.tif39170 (In the above general formula (4), R 3 represents a hydrogen atom or a methyl group, R 4 each independently represents a methyl group, an ethyl group, or a propyl group; R 5 represents a methyl group or a benzyl group, C represents O or NH, D represents an ethylene group or a propylene group, E represents an organic dye skeleton, and r represents any number of repetitions.

[0070] In resin B, the ratio of the structural unit (i) is preferably 35 to 70% by mass, more preferably 40 to 65% by mass. In addition, in resin B, the ratio of the structural unit (iv) is preferably 10 to 50% by mass, more preferably 15 to 45% by mass. The total of all structural units is 100% by mass. If the ratio of the structural unit (i) is less than 35% by mass, the amount of polyalkylene glycol chain becomes insufficient, resulting in a slight lack of steric repulsion and a decrease in dispersion stability. If the ratio of the structural unit (iv) is less than 10% by mass, the amount of the dye derivative in the blend during production becomes less than 5% by mass, resulting in a slight lack of adsorption to the organic pigment and a decrease in dispersion stability. On the other hand, if it exceeds 50% by mass, the amount of the dye derivative becomes excessive, which may cause the hue to change easily and the water resistance to decrease.

[0071] Resin B may further include a structural unit (ii) represented by the following general formula (3). The total content of structural unit (ii) and structural unit (iii) in resin B is preferably 0.5 to 60 mass%. Hereinafter, for convenience, "structural unit (ii)" and "structural unit (iii)" are collectively referred to as "structural unit (v)". That is, structural unit (v) is a structural unit containing structural unit (iii) in resin A and structural unit (ii) remaining without ion exchange.

[0072] TIFF2025057778000019.tif37170 (In the above general formula (3), R 3 represents a hydrogen atom or a methyl group, R 4 each independently represents a methyl group, an ethyl group, or a propyl group; R5 represents a methyl group or a benzyl group, C represents O or NH, D represents an ethylene group or a propylene group, X represents a chlorine atom, a bromine atom, or an iodine atom, and q represents any number of repetitions.

[0073] In the resin-treated pigment, the amount of resin B relative to 100 parts by mass of the organic pigment is preferably 30 to 70 parts by mass, more preferably 30 to 50 parts by mass. If the amount of resin B is less than 30 parts by mass relative to 100 parts by mass of the organic pigment, the dispersion stability may be insufficient. On the other hand, if the amount of resin B is more than 70 parts by mass relative to 100 parts by mass of the organic pigment, the viscosity of the pigment dispersion may increase excessively. In addition, since resin A, which is liquid under room temperature conditions, is used, the pigment may fuse due to heat during grinding or during storage.

[0074] <Pigment dispersion> One embodiment of the pigment dispersion of the present invention contains a liquid medium and the above-mentioned resin-treated pigment dispersed in the liquid medium. Hereinafter, the pigment dispersion of this embodiment will be described in detail.

[0075] (liquid medium) As the liquid medium, a normal liquid medium capable of dispersing a resin-treated pigment, such as a general organic solvent, can be used. Among them, it is preferable to use an ultraviolet-curable monomer as the liquid medium, since it can provide a pigment dispersion liquid useful as a raw material for preparing ultraviolet-curable inkjet ink (UVIJ ink).

[0076] The SP value of the liquid medium such as the ultraviolet curable monomer is preferably 7.0 to 10.0, more preferably 8.0 to 10.0. If the SP value of the liquid medium is less than 7.0, it may be difficult to disperse the resin-treated pigment, and the viscosity of the resulting pigment dispersion may become excessively high and aggregates may easily occur. On the other hand, if the SP value of the liquid medium is more than 10.0, the viscosity of the resulting pigment dispersion may become excessively high and the dispersion stability of the pigment may be slightly reduced. In addition, the mass ratio of the organic pigment to the liquid medium in the pigment dispersion is preferably organic pigment:liquid medium=2:98 to 50:50.

[0077] The "SP value" in this specification is the Hildebrand solubility parameter (SP value: δ) calculated from the Hansen solubility parameter (HSP value). The HSP value is a value calculated using the Y-MB method in the HSPiP (version 5.4.03) software, and is calculated by subtracting the dispersion force term (δ D ), polarity term (δ P ), and the hydrogen bond term (δ H The relationship between HSP and SP values ​​is given by the formula: δ 2 = δ D 2 +δ P 2 +δ H 2 , is expressed as:

[0078] As the ultraviolet curable monomer, a conventionally known monomer that is cured by irradiation with ultraviolet light can be used. The ultraviolet curable monomer may be a monofunctional monomer having one reactive group, or a polyfunctional monomer having two or more reactive groups. Furthermore, a photocurable oligomer or photocurable polymer having an ultraviolet curable group may be used in combination.

[0079] 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, cyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, adamantyl (meth)acrylate, adamantyl methyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and the like. Examples of the radical polymerizable monomer include tetrahydrofurfuryl (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, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, (3-ethyloxetan-3-yl)methyl (meth)acrylate, an adduct of phthalic anhydride and 2-hydroxyethyl (meth)acrylate, acroylmorpholine, N-vinylpyrrolidone, and N-vinylcaprolactam. Among them, those containing an acrylate skeleton with good ultraviolet curing properties are preferred.

[0080] Examples of polyfunctional monomers and photocurable oligomers include vinyloxyethoxyethyl (meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, poly(n=2 or more) ethylene glycol di(meth)acrylate, polypropylene glycol (n=2 or more) di(meth)acrylate, polybutylene glycol (n=2 or more) di(meth)acrylate, 2,2-bis(4-(meth)acryloxyethoxyphenyl)propane, 2,2-bis(4-(meth)acryloxydiethoxyphenyl)propane, trimethylolpropane diacrylate, bis(2-( Epoxy poly(meth)acrylates such as epoxy di(meth)acrylate obtained by reacting bisphenol A diepoxy with (meth)acrylic acid, 1,Urethane tri(meth)acrylate obtained by reacting 2-hydroxyethyl(meth)acrylate with a trimer of 6-hexamethylene diisocyanate, 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, dicyclohexyl diisocyanate with 2-hydroxyethyl(meth)acrylate, Examples of the poly(meth)acrylate include urethane poly(meth)acrylates such as urethane di(meth)acrylate obtained by reacting a urethane reaction product of xyl diisocyanate and poly(n=6-15)tetramethylene glycol with 2-hydroxyethyl (meth)acrylate, polyester (meth)acrylates obtained by reacting trimethylolethane with succinic acid and (meth)acrylic acid, and polyester poly(meth)acrylates such as polyester (meth)acrylates obtained by reacting trimethylolpropane with succinic acid, ethylene glycol, and (meth)acrylic acid. Among these, those containing an acrylate skeleton with good ultraviolet curing properties are preferred.

[0081] Examples of photocurable polymers include those having a plurality of radical polymerizable groups, such as (meth)acryloyloxy groups, at the ends or side chains of polymers such as poly(meth)acrylate, polyurethane, polyester, polyamide, polyimide, and polyepoxy resin.

[0082] In a general oil-based pigment dispersion, the dispersant is adsorbed to the pigment by ionic bonds between the acidic group of the pigment and the basic group of the resin used as the dispersant. Therefore, when a highly polar monomer (a compound having an amide bond such as acryloylmorpholine, vinylpyrrolidone, vinylcaprolactone, etc.; an ether-based compound such as acryloyloxyethyl vinyl ether, etc.) is used as the ultraviolet-curable monomer, the ionic bonds are easily dissociated, the dispersant is detached from the pigment, and the dispersibility of the pigment is likely to decrease. In contrast, in the case of the above-mentioned resin-treated pigment used in the pigment dispersion of this embodiment, since an organic dye skeleton is introduced into the resin B adsorbed to the pigment, the resin B is firmly adsorbed to the pigment and is not easily detached. Furthermore, since the structural unit (iv) is not easily dissolved in a highly polar monomer, the dispersion stability of the pigment can be maintained at a high level.

[0083] (Other Ingredients) The pigment dispersion and the UVIJ ink described later may further contain various additives. Examples of the additives include polymerization inhibitors, surfactants, antioxidants, UV absorbers, light stabilizers, leveling agents, thickeners, viscosity adjusters, preservatives, antifungal agents, dyes, waxes, fillers, acid generators, and alkali generators. Examples of the polymerization inhibitors include phenolic compounds such as p-methoxyphenol, t-butylcatechol, di-t-butyl-p-cresol, hydroquinone monomethyl ether, 3,5-di-t-butyl-4-hydroxytoluene, and 2,2'-methylenebis(4-methyl-6-t-butylphenol); quinone compounds such as p-benzoquinone; amine compounds such as p-benzylaminophenol, di-β-naphthyl-p-phenylenediamine, phenylhydroxylamine, and diethylhydroxylamine; oxime compounds such as quinonedioxime and cyclohexanoneoxime; and sulfur compounds such as phenothiazine. A photopolymerization initiator may be previously blended in the pigment dispersion.

[0084] The composition of the pigment dispersion can be set arbitrarily. As a specific example, the pigment dispersion preferably contains 5 to 30% by mass of the resin-treated pigment, 0.5 to 30% by mass of the polymer dispersant, and 40 to 94.5% by mass of the liquid medium such as the ultraviolet absorbing monomer. It is more preferable that the pigment dispersion contains 10 to 25% by mass of the resin-treated pigment, 1 to 25% by mass of the polymer dispersant, and 60 to 90% by mass of the liquid medium such as the ultraviolet absorbing monomer.

[0085] (Method of manufacturing pigment dispersion) The pigment dispersion can be prepared according to a conventional method. For example, a mixture of a monomer, a resin-treated pigment, a polymeric dispersant, and the like is prepared, and an organic solvent is added as necessary. A pigment dispersion can be obtained by performing a dispersion treatment using a paint shaker, a ball mill, an attritor, a sand mill, a horizontal media mill, a colloid mill, a roll mill, or the like. The pigment concentration can be adjusted by adding a monomer to the obtained pigment dispersion. In addition, other additives may be added as necessary. Furthermore, it is preferable to remove coarse particles by processing with a centrifuge or a filter.

[0086] To set the number average particle size (particle size distribution) of the pigment within the desired range, the following techniques are used: using small-sized grinding media, increasing the packing rate of the grinding media, lengthening the dispersion treatment time, slowing down the discharge speed, and classifying the particles after grinding with a filter or centrifuge. The viscosity of the pigment dispersion at 25°C is preferably 3 to 100 mPa·s.

[0087] <UV-curable inkjet ink and printing film> One embodiment of the ultraviolet-curable inkjet ink (UVIJ ink) of the present invention contains the above-mentioned pigment dispersion liquid using an ultraviolet-curable monomer as a liquid medium. One embodiment of the printed film of the present invention is a cured product of this UVIJ ink. The UVIJ ink of this embodiment is an inkjet ink in which an ultraviolet-curable monomer is used as a liquid medium and a cyan organic pigment is finely dispersed. The UVIJ ink of this embodiment is an environmentally friendly ink that contains substantially no volatile components, and in which the components applied to a recording medium are cured by irradiating ultraviolet light to form an image (printed film).

[0088] The UVIJ ink of the present embodiment may further contain, in addition to the pigment dispersion liquid described above, for example, a photopolymerization initiator, an ultraviolet-curable polymer, and the various additives described above. As the photopolymerization initiator, a photoradical polymerization initiator or a photocationic polymerization initiator can be used. Among them, it is preferable to use a photoradical polymerization initiator. As the photopolymerization initiator, a benzophenone-based photopolymerization initiator, a thioxanthone-based photopolymerization initiator, a ketoxime ester-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, and the like can be mentioned. The content of the photopolymerization initiator in the UVIJ ink is preferably 3 to 12% by mass. If the content of the photopolymerization initiator is less than 3% by mass, curing failure may easily occur. On the other hand, if the content of the photopolymerization initiator is more than 12% by mass, the photopolymerization initiator may remain or coloring may occur due to the photopolymerization initiator.

[0089] The above components are mixed and thoroughly stirred, and then filtered through a filter to obtain the desired UVIJ ink. The surface tension of the UVIJ ink at 25°C is preferably 15 to 45 mN / m, and more preferably 20 to 40 mN / m.

[0090] By using the UVIJ ink of the present invention, it is possible to record (print) images on various substrates by the inkjet recording method, which are printing films with high saturation, high color development, adhesion, and durability such as abrasion resistance, etc. Examples of substrates (recording media) include paper, photographic paper, glossy photographic paper, plastic film, fabric, ceramics, metal, etc. EXAMPLES

[0091] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" and "%" are by mass unless otherwise specified.

[0092] <Synthesis of Resin A> (Synthesis Example 1) In a reaction vessel, 156 parts of propylene glycol monomethyl ether (MPG), 100 parts of propylene glycol monomethacrylate (MAC-1) (trade name "Blenmar PP-2000", NOF Corporation, hydroxyl value 26 mg KOH / g, molecular weight converted from hydroxyl value 2,160, number average molecular weight converted into polystyrene measured by GPC (THF-GPC) using tetrahydrofuran (THF) as a developing solvent 3,400), 5.2 parts of α-methylstyrene (MSt), 10 parts of methyl methacrylate (MMA), and 35.5 parts of dimethylaminoethyl methacrylate (DMAEMA) were placed, stirred while flowing nitrogen, and heated to 75 ° C. 2,2'-azobis (isobutyric acid) dimethyl (V-601) (trade name "V-601", Fujifilm Wako Pure Chemical Industries, Ltd.) was added, polymerized for 8 hours, and then cooled to obtain a resin precursor solution. A portion of the solution was sampled and measured at 180°C using an infrared moisture meter to find that the solid content of the precursor solution was 50.1%, confirming that most of the solution had polymerized. The amine value of the precursor was measured using an automatic potentiometric titrator with a 0.1 mol / L isopropanolic hydrochloric acid solution to find that it was 85.1 mg KOH / g. When the precursor solution was added to water, it became cloudy and a white viscous substance precipitated. In other words, the precursor of the resin that was produced was insoluble in water.

[0093] In a separate container, 5.72 parts of benzyl chloride and 5.72 parts of MPG were placed, and the precursor solution was added at room temperature. After stirring for 1 hour, the mixture was heated to 80°C and reacted for 5 hours to obtain a viscous solution of resin A-1 with some turbidity. The solid content of the resin A-1 solution measured by sampling a portion was 50.5%. The solid content (resin A-1) was a viscous liquid at room temperature. The number average molecular weight (Mn) of resin A-1 in terms of polystyrene, measured by GPC (DMF-GPC) using a dimethylformamide (DMF) solution of 0.1 mmol / L lithium bromide as the developing solvent, was 9,400, and the molecular weight distribution (PDI = weight average molecular weight / number average molecular weight) was 1.85. In DMF-GPC, almost no peak of MAC-1 was detected, indicating that most of MAC-1 was introduced into resin A-1. The amine value of resin A-1 was 62.3 mg KOH / g, and it was found that 20 mol% of the amino groups in the precursor were converted to quaternary salts, i.e., the quaternary salt ratio was 20 mol%. The amount of quaternary salt contained in 1 g of resin A-1 was calculated to be 0.276 mmol. In the obtained resin A-1, the proportion of structural unit (i) was 61.0%, the proportion of structural unit (ii) was 7.8%, and the proportion of structural unit (iii) was 31.2%. When a solution of resin A-1 was added to water, it dissolved in water without producing insoluble matter.

[0094] (Synthesis Examples 2 and 3) A solution of resin A-2 and a solution of resin A-3 were obtained in the same manner as in the above Synthesis Example 1, except that the amounts of benzyl chloride shown in Table 1 were used.

[0095] TIFF2025057778000020.tif105170

[0096] <Production of resin-treated pigments> Example 1 In a beaker, 285.7 parts of CI Pigment Blue 15:3 (PB15:3) (product name "3463", Dainichi Seikagaku Kogyo Co., Ltd.) water paste (purity 35%) and 1,714 parts of ion-exchanged water were placed and stirred at 2,000 rpm using a disper to obtain a water slurry. 207 parts of copper phthalocyanine monosodium sulfonate (MSPCNa) aqueous solution (purity 2.5%, pH 8.9, transparent blue solution) represented by formula (A) was added to the water slurry and stirred at 2,000 rpm for 2 hours. When the water slurry after stirring was spotted on filter paper, the pigment was placed on the filter paper, and the MSPCNa caused bleeding around the pigment, and the back of the filter paper bled blue. The pH of the water slurry was 7.8.

[0097] In a separate container, 62.3 parts of the resin A-1 solution and 62.3 parts of ion-exchanged water were mixed to obtain a uniform mixture. The resulting mixture was gradually added to the water slurry. When the water slurry was spotted on filter paper, no bleeding or strike-through occurred. The mixture was heated to 60°C and stirred for 30 minutes, then filtered and washed with ion-exchanged water. The mixture was dried at 80°C for 24 hours using a dryer, and then pulverized using a pulverizer to obtain 133 parts of resin-treated pigment 1. The yield was 93%, and the non-volatile content measured after drying at 120°C was 99%. At least a portion of the structural unit (ii) in resin A was converted to structural unit (iv), and resin B derived from resin A was formed. The amount of quaternary ammonium salt (DMQ) relative to the amount of sulfonic acid ions was 1.2 molar equivalents. The amount of resin B relative to 100 parts of pigment was 37.1 parts. In the formed resin B, the proportion of structural unit (i) was 53.2%, the proportion of structural unit (iv) was 18.4%, and the proportion of other structural units (the total of structural unit (ii) and structural unit (iii)) was 28.3%.

[0098] (Examples 2 to 6, Comparative Examples 1 to 3) Resin-treated pigments 2 to 9 were obtained in the same manner as in Example 1, except that the formulations shown in Tables 2-1 and 2-2 were used. Details of the obtained resin-treated pigments are shown in Tables 2-1 and 2-2.

[0099] TIFF2025057778000021.tif99170

[0100] TIFF2025057778000022.tif112170

[0101] <Production of pigment dispersion> Example 7 A resin container was charged with 19.6 parts of resin-treated pigment 1 and 80.4 parts of isobornyl acrylate (IBXA, SP value: 8.34). 400 parts of zirconia beads with a diameter of 0.5 mm were further added and the container was sealed, and dispersion treatment was carried out using a paint shaker. The zirconia beads were separated and removed to obtain pigment dispersion 1. The viscosity (initial viscosity) of pigment dispersion 1 measured at 60 rpm and 25°C using an E-type viscometer was 25.0 mPa s. The number average particle diameter (initial number average particle diameter) of the pigment in pigment dispersion 1 measured using a dynamic light scattering particle size distribution meter was 103 nm.

[0102] A storage test was carried out by storing the obtained pigment dispersion liquid 1 for one week at 60° C. The ratio of the viscosity after the storage test based on the initial viscosity (viscosity retention rate) was 93%.

[0103] A filterability test was conducted by filtering 30 g of the obtained pigment dispersion liquid 1 at a load pressure of 0.04 MPa using a filter with a retention particle size of 5 μm (product name "PF-050", manufactured by ADVANTEC Co., Ltd.). The filterability was evaluated according to the following evaluation criteria, and was rated as "○". [Evaluation criteria for filterability] ◯: The entire amount of the liquid passed through, and the filtration time was good. △: The entire amount of liquid passed through. ×: The liquid did not pass through very well, and clogging occurred.

[0104] (Examples 8 to 12, Comparative Examples 4 to 6) Pigment dispersions 2 to 9 were obtained in the same manner as in Example 7, except that the formulations shown in Tables 3-1 and 3-2 were used. Details of the obtained pigment dispersions are shown in Tables 3-1 and 3-2.

[0105] TIFF2025057778000023.tif137170

[0106] TIFF2025057778000024.tif141170

[0107] <Manufacture of UVIJ Ink> (Example 13) 18 parts of Pigment Dispersion 1, 53.5 parts of PEA, 19 parts of acryloyloxyethoxyethyl vinyl ether (VEEA, manufactured by Nippon Shokubai Co., Ltd.), 5 parts of Photoinitiator 1 (trade name "Lucirin TPO", manufactured by BASF), and 4.5 parts of Photoinitiator 2 (trade name "Irgacure 819", manufactured by BASF) were mixed. After thorough stirring, the mixture was filtered through a 5 μm filter to obtain UVIJ Ink (UVIJINK-C-1). The viscosity of the obtained ink and the number average particle diameter of the pigment were measured. The results are shown in Table 4. Also, the above-mentioned storage test was conducted by putting the obtained ink into a brown sample bottle and storing it at 60 °C for 1 week. Then, the ratio of the viscosity after the storage test (viscosity retention rate) based on the initial viscosity, and the ratio of the number average particle diameter of the pigment after the storage test (particle diameter retention rate) based on the initial number average particle diameter were calculated. The results are shown in Table 4.

[0108] (Examples 14 to 18, Comparative Example 7) Except for using the formulations shown in Table 4, UVIJ Inks (UVIJINK-C-2 to 7) were obtained in the same manner as in Example 13 described above. The details of the obtained UVIJ Inks are shown in Table 4.

[0109] <Manufacture and Evaluation of UV-Cured Coating Film (Printing Film)> Using an automatic bar coater, UVIJ Ink was applied onto a PET film with a thickness of 100 μm so that the film thickness became 6 μm to form a coating film. Next, the formed coating film was cured using a UV curing device to form a UV-cured coating film (printing film).

[0110] (1) Reflectance Density The reflection density of the formed UV-cured coating film was measured (average value of 10 measurements at different positions) using a colorimeter (product name "i1PRO", manufactured by X-Rite). The reflection density of the UV-cured coating film was evaluated according to the following evaluation criteria. The results are shown in Table 4. [Reflection density evaluation criteria] ⊚: The reflection density was 2.35 or more and less than 2.40. ◯: The reflection density was 2.30 or more and less than 2.35. Δ: The reflection density was 2.25 or more and less than 2.30.

[0111] (2) Glossiness Using a surface gloss meter (product name "micro-tri-gloss", manufactured by BYK), the gloss of the formed UV-cured coating film at 20° (average value of values ​​measured seven times at different positions) was measured. The gloss of the UV-cured coating film was then evaluated according to the following evaluation criteria. The results are shown in Table 4. [Gloss evaluation criteria] ⊚: Glossiness was 100 or more and less than 105. ◯: Glossiness was 95 or more and less than 100. Δ: Glossiness was 90 or more and less than 95.

[0112] (3) Adhesion Using an automatic bar coater, the UVIJ ink was applied to a 250 μm thick PET film to a thickness of 6 μm to form a coating film. The coating film was then cured using a UV curing device to form a UV-cured coating film (printed film). An adhesion test was then conducted using the cross-cut method in accordance with the JIS standard (JIS K5600-5-6), and the adhesion of the UV-cured coating film was evaluated according to the following evaluation criteria. The results are shown in Table 4. [Adhesion evaluation criteria] 0: No peeling in any of the grids. 1: Minor delamination at the intersection of the cuts, less than 5% of the crosscut area affected. 2: Delamination at cut edges or intersections, with more than 5% but less than 15% affected. 3: Large amount of flaking along the edges of the cut, more than 15% but less than 35% affected. 4: Large amounts of flaking along the edges of the cut, with more than 35% but less than 65% affected. 5: The degree of peeling exceeded the rating of "4".

[0113] TIFF2025057778000025.tif131170 [Industrial Applicability]

[0114] The resin-treated pigment and pigment dispersion of the present invention are useful as raw materials for preparing ultraviolet-curable inkjet inks, and biomass-derived monomers can be actively used.

Claims

1. A mixture containing 100 parts by mass of a cyan organic pigment, 5 to 20 parts by mass of a dye derivative represented by the following general formula (1), and water, adding 20 to 70 parts by mass of a resin A that is liquid under room temperature conditions, the resin A having a number average molecular weight of 9,000 to 30,000 and a quaternary chloride ratio of 20 to 35 mol%, which resin A has 40 to 80 mass% of structural units (i) represented by the following general formula (2), 3 to 30 mass% of structural units (ii) represented by the following general formula (3), and 1 to 57 mass% of other structural units (iii); A resin-treated pigment obtained by precipitating a resin B in which at least a portion of the structural unit (ii) is converted to a structural unit (iv) represented by the following general formula (4): (In the general formula (1), M represents a lithium atom, a sodium atom, or a potassium atom, and E represents an organic dye skeleton.) (In the general formula (2), R represents a hydrogen atom or a methyl group, and R １ represents a hydrogen atom or a methyl group, R ２ represents a hydrogen atom, a methyl group, or a butyl group, A represents O or NH, B represents an ethylene group or a methylethylene group, X represents O, NHCOO, or NHCONH, n is a number from 20 to 100 representing the average number of repeating units, and p represents an arbitrary number of repeating units. (In the general formula (3), R ３ represents a hydrogen atom or a methyl group, R ４ each independently represents a methyl group, an ethyl group, or a propyl group; R ５ represents a methyl group or a benzyl group, C represents O or NH, D represents an ethylene group or a propylene group, X represents a chlorine atom, a bromine atom, or an iodine atom, and q represents any number of repetitions. (In the general formula (4), R ３ represents a hydrogen atom or a methyl group, R ４ each independently represents a methyl group, an ethyl group, or a propyl group; R ５ represents a methyl group or a benzyl group, C represents O or NH, D represents an ethylene group or a propylene group, E represents an organic dye skeleton, and r represents any number of repetitions.

2. 2. The resin-treated pigment according to claim 1, wherein the organic dye skeleton represented by E in the general formula (1) is a phthalocyanine dye skeleton.

3. 2. The resin-treated pigment according to claim 1, wherein the content of said resin B is 30 to 70 parts by mass based on 100 parts by mass of said organic pigment.

4. 2. The resin-treated pigment according to claim 1, wherein the structural unit (iii) is a structural unit derived from α-methylstyrene.

5. The resin-treated pigment according to claim 4, wherein the structural unit (iii) comprises a structural unit (iii-1) represented by the following general formula (5): (In the general formula (5), R ３ represents a hydrogen atom or a methyl group, C represents O or NH, D represents an ethylene group or a propylene group, R ４ each independently represents a methyl group, an ethyl group, or a propyl group, and s represents an arbitrary number of repetitions.

6. A pigment dispersion comprising a liquid medium and the resin-treated pigment according to any one of claims 1 to 5 dispersed in the liquid medium.

7. The pigment dispersion according to claim 6 , wherein the liquid medium is an ultraviolet-curable monomer.

8. An ultraviolet-curable ink-jet ink comprising the pigment dispersion liquid according to claim 7.

9. A printed film which is a cured product of the ultraviolet-curable ink-jet ink according to claim 8.

Images