UV-curable inkjet composition, cured film, color filter, solid-state image sensor, and image display device.

Abstract

The present invention aims to provide an ultraviolet-curable inkjet composition, a cured film, a color filter, a solid-state image sensor equipped with the color filter, and an image display device that have a high concentration of colorant and high coloring power, yet have low viscosity, good storage stability, excellent filterability, and few surface foreign matter when a cured film is formed. [Solution] The above problem is solved by an ultraviolet-curable inkjet composition comprising a colorant (A), a resin (B), a polymerizable compound (C), and a polymerization initiator (D), wherein the content of the colorant (A) is 9.0% by mass or more and 16.0% by mass or less in the ultraviolet-curable inkjet composition, and the polymerizable compound (C) comprises a monofunctional and / or bifunctional monomer (C1) having a viscosity of 10 mPa·s or less, and the content of the monomer (C1) is 90% by mass or more and 100% by mass or less in the polymerizable compound (C).

Description

Technical Field

[0001] The present invention relates to an ultraviolet-curable inkjet composition, a cured film, a color filter, a solid-state imaging device, and an image display device.

Background Art

[0002] A solventless inkjet recording method has attracted attention, in which an ink curable by irradiation with radiation such as ultraviolet rays is applied in an image-like manner to a desired material, and the ink applied in an image-like manner is cured to record an image. In recent years, in color filters used in smartphones and tablet terminals, development of a solventless inkjet recording method has been progressing from the viewpoints of improving yield, simplifying the manufacturing process, etc. With the thinning and weight reduction of smartphones and tablet terminals, the color filter incorporated in a liquid crystal display or an organic EL display has been thinned, and also, in order to enhance color reproducibility, high coloring power and high concentration of ink have been demanded. In an ultraviolet-curable inkjet composition, it is important to ensure the dispersion stability of a colorant. When there is a problem in dispersion stability, various problems such as deposition of aggregated foreign substances on the film surface and deterioration of the ejection property of the inkjet composition are caused. As a method for obtaining a stable inkjet composition, for example, Patent Document 1 proposes a composition using a pigment derivative. Also, Patent Documents 2 and 3 disclose proposals for defining the content ratio of a monofunctional monomer and a monomer having two or more functional groups. However, although the inkjet compositions disclosed in these documents have dispersion stability and ejection stability, the ejection stability and dispersion stability at high concentration are not mentioned.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

[0004] The present invention aims to provide an ultraviolet-curable inkjet composition, a cured film, a color filter, a solid-state image sensor equipped with the color filter, and an image display device that have a high concentration of colorant and high coloring power, yet have low viscosity, good storage stability, excellent filterability, and few surface foreign matter when a cured film is formed. [Means for solving the problem]

[0005] As a result of diligent research to solve the aforementioned problems, the present inventors have found that by specifying the content of monofunctional and / or bifunctional monomers having a viscosity of 10 mPa·s or less at 25°C, the above problems can be solved when the colorant concentration of the UV-curable inkjet composition is 9.0% by mass or more and 16.0% by mass or less, leading to the present invention.

[0006] In other words, the present invention relates to an ultraviolet-curable inkjet composition comprising a colorant (A), a resin (B), a polymerizable compound (C), and a polymerization initiator (D), The content of colorant (A) is 9.0% by mass or more and 16.0% by mass or less in the UV-curable inkjet composition. The polymerizable compound (C) comprises a monofunctional and / or bifunctional monomer (C1) having a viscosity of 10 mPa·s or less at 25°C. The present invention relates to an ultraviolet-curable inkjet composition in which the content of a monofunctional or / or bifunctional monomer (C1) is 90% by mass or more and 100% by mass or less in a polymerizable compound (C).

[0007] Furthermore, the present invention relates to an early ultraviolet-curable inkjet composition having a viscosity of 10 mPa·s or more and 40 mPa·s or less at 25°C.

[0008] Furthermore, the present invention relates to an early ultraviolet-curable inkjet composition in which the coloring agent (A) contains a pigment, and the particle size of the pigment is 50 to 150 nm or less.

[0009] Furthermore, the present invention relates to the ultraviolet-curable inkjet composition wherein the polymerization initiator (D) comprises an acylphosphine compound and / or an oxime ester compound.

[0010] Furthermore, the present invention relates to a cured film formed by the aforementioned ultraviolet-curable inkjet composition.

[0011] Furthermore, the present invention relates to a color filter having a substrate and the cured film.

[0012] Furthermore, the present invention relates to a solid-state image sensor comprising the aforementioned color filter.

[0013] Furthermore, the present invention relates to an image display device comprising the aforementioned color filter. [Effects of the Invention]

[0014] The present invention provides an ultraviolet-curable inkjet composition, a cured film, a color filter, a solid-state image sensor, and an image display device that have a high concentration of colorant and high coloring power, yet have low viscosity, good storage stability, excellent filterability, and few surface foreign matter when a cured film is formed. [Modes for carrying out the invention]

[0015] The embodiments for carrying out the ultraviolet-curable inkjet composition of the present invention will be described in detail below. However, the present invention is not limited to the following embodiments and can be modified and implemented within the scope of solving the problem.

[0016] In this specification, unless otherwise specified, "(meth)acryloyl," "(meth)acrylic," "(meth)acrylic acid," "(meth)acrylate," "(meth)acryloyloxy," or "(meth)acrylamide" means, respectively, "acryloyl and / or methacryloyl," "acrylic and / or methacrylic," "acrylic acid and / or methacrylic acid," "acrylate and / or methacrylate," "acryloyloxy and / or methacryloyloxy," or "acrylamide and / or meth-acrylamide." It means "crilamide." Also, "CI" stands for Color Index (CI; published by The Society of Dyers and Colourists).

[0017] <Coloring agent (A)> The UV-curable inkjet composition of the present invention contains a colorant (A) in an amount of 9.0% to 16.0% by mass. This range results in high coloring power and makes the composition suitable for color filter formation. The colorant (A) can be arbitrarily selected from various conventionally known pigments and dyes. Specific examples of colorants (A) usable in the UV-curable inkjet composition of the present invention are shown below by their color index numbers.

[0018] Examples of red pigments include CI Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 12, 14, 15, 16, 17, 21, 22, 23, 31, 32, 37, 38, 41, 47, 48, 48:1, 48:2, 48:3, 48:4, 49, 49:1, 49:2, 50:1, 52:1, 52:2, 53, 53:1, 53:2, 53:3, 57, 57:1, 57:2, 58:4, 60, 63, 6 3:1, 63:2, 64, 64:1, 68, 69, 81, 81:1, 81:2, 81:3, 81:4, 83, 88, 90:1, 101, 101:1, 104, 108, 108:1, 109, 112, 113, 114, 122, 123, 144, 146, 147, 149, 151, 166, 168, 169, 170, 172, 173, 174, 175, 176, 177, 178, 179, 181, 184, 185, 187, 188, 190, 193, 194, 200, 202, 206, 207, 208, 209, 210, 214, 216, 220, 221, 224, 230, 231, 232, 233, 235, 236, 237, 238, 239, 242, 243, 245, 247, 249, 250, 251, 253, 254, 255, 256, 257, 258, 259, 260, 262, 2 Red pigments such as 63, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 291, 295, or 296, the pigment described in Japanese Patent Publication No. 2014-134712, the pigment described in Japanese Patent Publication No. 6368844, etc. can be used. In addition, red dyes such as xanthene, azo, disazo, and anthraquinone dyes can also be used. Specifically, examples include xanthene acid dye salt compounds such as CI Acid Red 52, 87, 92, 289, and 338. In particular, CI Pigment Red 122, 177, 254, and 291 are preferred from the viewpoint of coloring power and storage stability.

[0019] As the orange pigment, you can use orange pigments such as CI Pigment Orange 34, 36, 38, 43, 51, 55, 59, 61, 62, 64, 71, or 73.

[0020] As for yellow pigments, CI Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 20, 24, 31, 32, 34, 35, 35:1, 36, 36:1, 37, 37:1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 86, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 125, 126, 127, Yellow pigments such as 128, 129, 137, 138, 139, 147, 148, 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181, 182, 185, 187, 188, 193, 194, 198, 199, 213, 214, 218, 219, 220, 221, 231, 233, or 234 can be used. Additionally, yellow dyes such as quinoline, azo, disazo, and methine can also be used. In particular, CI Pigment Yellow 138, 139, 150, 185, and 231 are preferred in terms of coloring power and storage stability.

[0021] As green pigments, for example, zinc phthalocyanine pigments described in CI Pigment Green 7, 10, 36, 37, 58, 59, 62, 63, Japanese Patent Publication No. 2008-19383, Japanese Patent Publication No. 2007-320986, Japanese Patent Publication No. 2004-70342, International Publication No. 2015 / 118720, etc., and aluminum talocyanine pigments described in Japanese Patent No. 4893859, etc. can be used. In particular, CI Pigment Green 7, 36, 58, 59, 62, and 63 are preferred in terms of coloring power and storage stability.

[0022] For example, CI Pigment Blue 1, 1:2, 1:3, 2, 2: Blue pigments such as 1, 2:2, 3, 8, 9, 10, 10:1, 11, 12, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 18, 19, 22, 24, 24:1, 53, 56, 56:1, 57, 58, 59, 60, 61, 62, and 64 can be used.

[0023] As purple pigments, for example, CI Pigment Violet 1, 1:1, 2, 2:2, 3, 3:1, 3:3, 5, 5:1, 14, 15, 16, 19, 23, 25, 27, 29, 31, 32, 37, 39, 42, 44, 47, 49, and 50 can be used.

[0024] In addition, examples of inorganic pigments include titanium dioxide, barium sulfate, zinc oxide, lead sulfate, lead yellow, zinc yellow, red iron(III) oxide, cadmium red, ultramarine, Prussian blue, chromium oxide green, cobalt green, amber, and synthetic iron black. Inorganic pigments are used in combination with organic pigments to ensure good coating properties, sensitivity, and developability while maintaining a balance between saturation and brightness.

[0025] From the viewpoint of storage stability, it is preferable that the colorant (A) contains at least one selected from phthalocyanine pigments, isoindoline pigments, azo metal complex pigments, quinophthalone pigments, diketopyrrolopyrrole pigments, and anthraquinone pigments, with phthalocyanine pigments, isoindoline pigments, azo metal complex pigments, quinophthalone pigments, and anthraquinone pigments being particularly preferred.

[0026] (Pigment refinement) When the colorant (A) used in the UV-curable inkjet composition of the present invention is a pigment, it is preferable to use it after micronization. The micronization method is not particularly limited, and for example, wet grinding, dry grinding, or dissolution extraction methods can all be used. As exemplified in the present invention, micronization can be performed by salt milling using a kneader method, which is a type of wet grinding. The average primary particle size of the pigment, as determined by TEM (transmission electron microscope), is preferably in the range of 50 to 150 nm, and more preferably 55 to 120 nm. Having the average primary particle size in the above range results in good dispersion stability, high transmittance, and a good surface condition when a cured film is formed. The average primary particle diameter is the average value of approximately 200 particles arbitrarily selected from magnified images obtained using a TEM (transmission electron microscope). If a particle has both a long axis and a short axis, the length of the long axis is used.

[0027] Salt milling is a process in which a mixture of pigment, water-soluble inorganic salt, and water-soluble organic solvent is mechanically kneaded while heated using batch or continuous kneading machines such as kneaders, two-roll mills, three-roll mills, ball mills, attritors, sand mills, and planetary mixers, and then washed with water to remove the water-soluble inorganic salt and water-soluble organic solvent. The water-soluble inorganic salt acts as a crushing aid, and the pigment is crushed by utilizing the high hardness of the inorganic salt during salt milling. By optimizing the conditions for salt milling the pigment, it is possible to obtain pigments with a very fine primary particle size, a narrow distribution width, and a sharp particle size distribution.

[0028] As the water-soluble inorganic salt, sodium chloride, potassium chloride, sodium sulfate, etc., can be used, but from the standpoint of cost, sodium chloride (table salt) is preferred. From the perspective of both processing efficiency and production efficiency, it is preferable to use 50 to 2000 parts by weight of the water-soluble inorganic salt per 100 parts by weight of pigment, and most preferably 300 to 1000 parts by weight.

[0029] The water-soluble organic solvent serves to wet the pigment and the water-soluble inorganic salt. It is not particularly limited as long as it dissolves (miscible) in water and does not substantially dissolve the inorganic salt used. However, since the temperature rises during salt milling and the solvent is prone to evaporation, a high-boiling-point solvent with a boiling point of 120°C or higher is preferred from a safety standpoint. For example, 2-methoxyethanol, 2-butoxyethanol, 2-(isopentyloxy)ethanol, 2-(hexyloxy)ethanol, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, liquid polyethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, liquid polypropylene glycol, etc. are used. The water-soluble organic solvent is preferably used in an amount of 5 to 1000 parts by weight, and most preferably 50 to 500 parts by weight, per 100 parts by weight of pigment.

[0030] When the pigment is subjected to salt milling, a resin may be added as needed. The type of resin used is not particularly limited, and natural resins, modified natural resins, synthetic resins, synthetic resins modified with natural resins, etc., can be used. The resin used is preferably solid at room temperature, insoluble in water, and more preferably partially soluble in the above organic solvent. The amount of resin used is preferably in the range of 5 to 200 parts by weight per 100 parts by weight of pigment.

[0031] <Pigment derivatives> In the present invention, the colorant (A) may contain a pigment derivative. Examples of pigment derivatives include compounds having an acidic group, a basic group, a neutral group, etc., in addition to the pigment structure or triazine structure. The acidic group, basic group, neutral group, etc., may be directly bonded to the pigment structure or triazine structure, or they may be bonded via a linking group.

[0032] Examples of pigment structures include diketopyrrolopyrrole pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, perinone pigments, perylene pigments, thiaidine indigo pigments, benzimidazolon pigments, indole pigments such as benzoisoindole, isoindoline pigments, isoindolinone pigments, quinophthalone pigments, naphthol pigments, surene pigments, metal complex pigments, and azo pigments such as azo, disazo, and polyazo.

[0033] Examples of acidic groups include sulfo groups, carboxyl groups, and phosphate groups. Examples of basic groups include sulfonamide groups and tertiary amino groups. Examples of neutral groups include salts of the above-mentioned acidic groups, salts of basic groups, phenyl groups, and phthalimide groups.

[0034] In the present invention, the pigment derivative is preferably a compound having an organic pigment structure or a triazine structure, with at least one selected from the group consisting of an acidic group, a basic group, a group having a salt structure, and a phthalimide group, and more preferably has an acidic substituent.

[0035] Specific examples of pigment derivatives are shown below, but the invention is not limited to these.

[0036] <<Diketopyrrolopyrrole-based pigment derivatives>> [ka]

[0037] <<Phthalocyanine-based pigment derivatives>> [ka]

[0038] <<Anthraquinone-based pigment derivatives>> [ka]

[0039] <<Quinacridone-based pigment derivatives>>

change

[0040] <<Surface pigment derivative>>

change

[0041] <<チアジンインジゴ pigment derivative>>

change

[0042] <<Torion pigment derivative>>

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[0043] <<Polychrome pigment derivatives>>

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[0044] <<Coronol pigment derivative>>

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[0045] <<Nano-based pigment inducer>>

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[0046] <<アゾ-based pigment inducer>>

change

[0047] In general formulas (101) to (112), (114) to (128), and (130) to (133), R 101 ~R 117 、R 129 、R 130 、R 141 ~R 145 each independently represents a hydrogen atom, a hydroxyl group, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a phthalimidoalkyl group which may have a substituent, an acyl group which may have a substituent, an amino group, a sulfo group, a carboxyl group, a phosphate group, a halogen group, a group represented by general formulas (150) to (155), (158), or (159). m and n each independently represent a positive integer. However, when there are a plurality of substituents in one molecule, one or more are substituents other than a hydrogen atom. Also, when there is only one substituent in one molecule, it is a substituent other than a hydrogen atom.

[0048] In general formula (113), R 118 represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, an alkoxy group, an aryloxy group, -SO2R 177 , or -NR 178 R 179 . However, R 177 represents a hydrogen atom, an alkyl group which may have a substituent, a phenyl group which may have a substituent, or a halogen atom, and R 178 and R 179 each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a heterocyclic ring which may contain an additional nitrogen, oxygen or sulfur atom formed integrally by R 178 and R 179 . R 119 represents a hydrogen atom, an alkyl group which may have a substituent, or an acyl group which may have a substituent. R 120 , R 121 , R 123 ~R 128Each of these independently comprises a hydrogen atom, an optionally substituted alkyl group, an optionally substituted phenyl group, a halogen atom, a cyano group, an optionally substituted alkoxy group, or NR 180 R 181 However, R 180 and R 181 These are, independently of each other, a hydrogen atom, an alkyl group which may have substituents, or R 180 and R 181 Together, they represent a heterocycle that may contain further nitrogen, oxygen, or sulfur atoms. R 122 This represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted acyl group, or a group represented by general formulas (150) to (155).

[0049] In general formula (129), R 131 ~R 140 Each of these independently represents a hydrogen atom, a halogen atom, an alkyl group, a perfluoroalkyl group, an alkoxyl group, or a group represented by general formula (150), (153), or (159). 131 ~R 140 The adjacent groups may be bonded by -NHCONH- groups to form a benzimidazolon ring. 131 ~R 140 At least one of these is a group represented by general formula (150), (153), or (159).

[0050] [ka] JPEG0007841632000016.jpg143170

[0051] In general formulas (150) to (155), X1 represents a direct bond, -SO2-, -CO-, -CH2-, -CH2NHCOCH2-, -CONHC6H4CO-, or -CONHC6H4-. Y1 is directly coupled, -NR 170 SO2-, -SO2NR 170 -, -CONR 170 -, - NR 170CO- or -CH2NR 170 COCH2NR 170 - represents Y2 represents a direct bond, an optionally substituted arylene group, or an optionally substituted heteroaromatic ring, and these groups are -NR 170 They may be linked to each other by divalent linking groups selected from -, -O-, -SO2-, or CO-. Y3 is directly bonded, -NR 170 - or -O- represents. 'o' represents an integer between 0 and 20. M1 represents hydrogen, copper, zinc, manganese, nickel, cobalt, and iron atoms. M2 represents a hydrogen atom, calcium atom, barium atom, strontium atom, manganese atom, or aluminum atom. i represents the valence of M2. R 150 and R 151 Each of these can independently be an optionally substituted alkyl group, an optionally substituted alkenyl group, an optionally substituted phenyl group, or R 150 and R 151 Together, they represent a heterocycle that may have substituents, further containing nitrogen, oxygen, or sulfur atoms. R 152 ~R 156 , R 159 ~R 162 Each of these independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkenyl group, an optionally substituted phenyl group, or a polyoxyalkylene group. R 157 and R 158 These are, independently, groups represented by the following general formulas (156) or (157), -O-(CH2) o -R 171 , -OR 172 , -NR 173 R 174 , represents -Cl, -F or Y3-Y2-Y1-Q, R 157 and R 158 Either one of them is a group represented by the following general formula (156) or (157), -O-(CH2)o -R 171 , -OR 172 , or NR 173 R 174 That is the case. R 170 This represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted phenyl group. R 171 R represents a heterocyclic residue which may have substituents. 172 ~R 174 Each of the following independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted phenyl group, and Q represents an organic dye residue.

[0052] [ka]

[0053] In the general formula (156), Z1 is -NR 170 - represents -CONH- or -O-, and Z2 represents an optionally substituted alkylene group, an optionally substituted alkenylene group, or an optionally substituted arylene group, and these groups are -NR 170 They may be linked together by divalent linking groups selected from -, -O-, -SO2-, or CO-. However, R 170 This is R in general formulas (150) to (155). 170 It is synonymous with [the above]. R 150 and R 151 Each of these can independently be an optionally substituted alkyl group, an optionally substituted alkenyl group, an optionally substituted phenyl group, or R 150 and R 151 Together, they represent a heterocycle that may have substituents, further containing nitrogen, oxygen, or sulfur atoms.

[0054] [ka]

[0055] In the general formula (157), Z3 represents a single bond connecting a triazine ring and a nitrogen atom, -NR 175 -, -NR 175 -, -NR 175 -Z4-CO-, -NR 176 -, -NR 175 -Z4-SO2-, -NR 175 -Z4-SO2NR 176 -, -O-Z4-CO-, -O-Z4-CONR 175 -, -O-Z4-SO2-, or O-Z4-SO2NR 175 -, R 175 and R 176 each independently represent a hydrogen atom, an alkyl group which may have a substituent, an alkenyl group which may have a substituent or a phenyl group which may have a substituent, and Z4 represents an alkylene group which may have a substituent, an alkenylene group which may have a substituent or an arylene group which may have a substituent. R 152 ~R 156 each independently represent a hydrogen atom, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, a phenyl group which may have a substituent or a polyoxyalkylene group.

[0056]

Chemical formula

[0057]

Chemical formula

[0058] In the general formula (159), X2 represents -SO2-, -CO-, -NH-, -SO2NH-, -NHSO2-, -CONH- or -NHCO-, and R 163 ~R 167 each independently represent a hydrogen atom, an alkoxyl group, an amino group, a sulfo group, a carboxy group, a phosphoric acid group or a group represented by the general formulas (150) to (155).

[0059] The alkyl group, which may have substituents, is preferably a linear alkyl group having 1 to 20 carbon atoms, and the substituents are preferably hydrogen or halogen groups. The phthalimide alkyl group, which may have substituents, is preferably an alkyl group having 1 to 3 carbon atoms, and the substituents are preferably hydrogen or a halogen group. The acyl group, which may have substituents, is preferably an acyl group having 1 to 10 carbon atoms as an alkyl group, and preferably a hydrogen or halogen group as an substituent. The alkoxy group, which may have substituents, is preferably a linear alkoxy group having 1 to 5 carbon atoms as the alkyl group, and hydrogen or halogen groups are preferred as the substituents. The alkenyl or alkenylene group, which may have substituents, preferably has hydrogen or a linear alkyl group having 1 to 10 carbon atoms as substituents. The phenyl group, which may have substituents, preferably has hydrogen, a halogen group, a linear alkyl group having 1 to 10 carbon atoms, or an alkoxy group as substituents. The arylene group, which may have substituents, preferably has hydrogen, a halogen group, a linear alkyl group having 1 to 10 carbon atoms, or an alkoxy group as substituents. The heterocycles that may have substituents are preferably azacyclobutane, pyrrolidine, piperidine, tetrahydrofuran, tetrahydropyran, tetrahydrothiophene, and tetrahydrothiopyran, and the substituents that may be present are preferably hydrogen, halogen groups, linear alkyl groups having 1 to 10 carbon atoms, and alkoxy groups. The heteroaromatic ring, which may have substituents, is preferably pyrrole, pyridine, furan, or thiophene, and the substituents that may be present are preferably hydrogen, a halogen group, a linear alkyl group having 1 to 10 carbon atoms, or an alkoxy group.

[0060] In the ultraviolet-curable inkjet composition of the present invention, the pigment derivative is preferably in a total amount of 1 to 30% by mass, and more preferably in a total amount of 3 to 20% by mass, in the colorant (A).

[0061] <Resin (B)> The UV-curable inkjet composition of the present invention contains resin (B). Resin (B) is incorporated for the purpose of dispersing particles such as pigments in the UV-curable inkjet composition, or as a binder. Resins used primarily to disperse particles such as pigments are also called dispersants. However, these uses of the resin are just examples, and it can also be used for purposes other than those described above.

[0062] Regarding dispersants, references to publicly available documents such as Japanese Patent Publication No. 2011-225848 may be made as appropriate. Specifically, examples include Lubrizol's SOLSPERSE series (e.g., SOLSPERSE 16000, 21000, 32000, 33000, 41000, J180, J200, etc.), BIC-Chemie's DISPERBYK series (e.g., DISPERBYK 102, 110, 111, 118, 165, 168, 190, 2013, etc.), and Evonik's TEGO Dispers series (e.g., TEGO Dispers 610, 630, 651, 655, 750W, 755W, etc.).

[0063] <Polymerizable compound (C)> The ultraviolet-curable inkjet composition of the present invention contains a polymerizable compound (C). While the polymerizable compound (C) is not particularly limited, conventionally known monofunctional, difunctional, and polyfunctional monomers and oligomers with three or more functions can be used. The polymerizable compound (C) may be used alone or in combination of two or more. The content of polymerizable compound (C) is preferably 71.5% to 82.5% by mass in the UV-curable inkjet composition. From the viewpoint of low viscosity and filterability, 71.5% to 80.0% by mass is more preferable.

[0064] Examples of monofunctional monomers include monofunctional acrylic monomers and monofunctional vinyl monomers. Specific examples of compounds include benzyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, (ethoxylated (or propoxylated)) 2-phenoxyethyl (meth)acrylate, dicyclopentenyl (oxyethyl) (meth)acrylate, and ethoxyethyl. Diethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, 2-methoxyethyl (methacrylate, methoxytriethylene glycol) Methacrylate, 2-ethoxyethyl methacrylate, ethoxyethoxyethyl methacrylate, methoxydipropylene glycol (methacrylate) Dipropylene glycol (meth)acrylate, nonylphenol EO modified acrylate, nonylphenol PO modified acrylate, o-phenylphenol EO modified acrylate, 2-ethylhexyl EO modified acrylate, β-carboxyethyl (meth)acrylate, trimethylolpropane formal (meth)acrylate, isoamyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isoboronyl (meth)acrylate, norbornyl (meth)acrylate Dicyclopentanyl (meth)acrylate, isooctyl (meth)acrylate, Lauryl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 1,4-cyclohexanedimethanol (meth)acrylate, 2-hydroxy Examples include monofunctional acrylic monomers such as ethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, acryloylmorpholine, and N-acryloyloxyethylhexahydrophthalimide, as well as monofunctional vinyl monomers such as N-vinylcaprolactam, N-vinylpyrrolidone, and N-vinylformamide. These compounds may be used individually or in combination of two or more.

[0065] Polyfunctional monomers include compounds having two or more polymerizable functional groups within their molecule. Examples include polyfunctional acrylic monomers other than 2-(2-vinyloxyethoxy)ethyl acrylate, and vinyl monomers. Examples of specific compounds include dimethylol tricyclodecane di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, and propoxylated bisphenol A. Di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, (poly ) Ethylene glycol di(meth)acrylate, (ethoxylated (or propoxylated) 1 Examples include 6-hexanediol di(meth)acrylate, 1,9-nonanediol acrylate, 1,10-decanediol diacrylate, (ethoxylated (or propoxylated)) neopentyl glycol di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, (neopentyl glycol modified) trimethylolpropane di(meth)acrylate, tripropylene glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, pentaerythritol tri(or tetra)(meth)acrylate, trimethylolpropane tri(or tetra)(meth)acrylate, tetramethylolmethane tri(or tetra)(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. Another example of a polyfunctional monomer is a polyfunctional vinyl monomer containing multiple vinyl groups within its molecule. Specific examples of compounds include butanediol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, cyclohexanedimethanol divinyl ether, trimethylolpropane divinyl ether, pentaerythritol tri(or tetra)vinyl ether, trimethylolpropanediallyl ether, and pentaerythritol tri(or tetra)allyl ether. These compounds may be used individually or in combination of two or more. Note that "EO modification" refers to ethylene oxide modification, and "PO modification" refers to propylene oxide modification.

[0066] (Monomer (C1)) The UV-curable inkjet composition of the present invention comprises a monofunctional and / or bifunctional monomer (C1) as a polymerizable compound (C), having a viscosity of 10 mPa·s or less at 25°C. The viscosity of monomer (C1) is preferably 0.5 mPa·s or more and 10 mPa·s or less, and more preferably 0.5 mPa·s or more and 8.0 mPa·s or less from the viewpoint of low viscosity. The viscosity of the monomer shall be measured using an E-type viscometer (ELD-type viscometer manufactured by Toki Sangyo Co., Ltd.) at 25°C and a rotation speed of 50 rpm. The monomer (C1) content is 90% to 100% by mass of the polymerizable compound (C). From the viewpoint of low viscosity and filterability, 95% to 100% by mass is more preferable. Normally, as pigment concentration increases, pigment particles tend to aggregate, leading to increased viscosity of the composition and deterioration of filterability and surface impurities. However, by keeping the monomer (C1) within the above range, it is possible to maintain low viscosity and ensure dispersibility even at high pigment concentrations, dramatically improving the filterability and surface impurities of the composition.

[0067] Examples of monofunctional and / or bifunctional monomers (C1) with a viscosity of 10 mPa·s or less at 25°C include isobornyl acrylate (viscosity 7.7 mPa·s), benzyl acrylate (viscosity 2.2 mPa·s), 2-phenoxyethyl (meth)acrylate (viscosity 9.0 mPa·s), dipropylene glycol diacrylate (viscosity 8.0 mPa·s), 1,6-hexanediol diacrylate (viscosity 7.0 mPa·s), and 1,9-nonanediol diacrylate (viscosity 8.0 mPa·s). Among these, dipropylene glycol diacrylate is preferred from the viewpoint of storage stability and dispersibility.

[0068] Furthermore, 2-(2-vinyloxyethoxy)ethyl acrylate (viscosity 3.7 mPa·s) is also preferred as the monomer (C1). 2-(2-vinyloxyethoxy)ethyl acrylate is commercially available, for example, as "VEEA" and "VEEA-AI" manufactured by Nippon Shokubai Co., Ltd. 2-(2-vinyloxyethoxy)ethyl acrylate has low viscosity and high reactivity. Therefore, it is excellent as a material for producing low-viscosity, highly sensitive UV-curable inkjet compositions. The content of 2-(2-vinyloxyethoxy)ethyl acrylate is preferably 5 to 70% by mass, and more preferably 5 to 60% by mass, based on the total weight of the UV-curable inkjet composition.

[0069] In the ultraviolet-curable inkjet composition of the present invention, from the viewpoint of viscosity and filterability, it is preferable to add monomer (C1) when mixing pigments, pigment derivatives, etc. and performing dispersion treatment, so as to adhere it to the surface of the pigments, pigment derivatives, etc.

[0070] <Polymerization initiator (D)> The ultraviolet-curable inkjet composition of the present invention contains a polymerization initiator (D). The polymerization initiator that can be used in the present invention may be a known polymerization initiator. For example, it is preferable to use a polymerization initiator that generates radicals by molecular cleavage or hydrogen abstraction. In the present invention, polymerization initiator (D) may be used alone or in combination of two or more. Furthermore, a polymerization initiator that generates radicals and a polymerization initiator that generates cations may be used in combination.

[0071] Specific examples of polymerization initiators (D) include 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 1-[4- (2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-p Lopionyl)-benzyl]-phenyl}-2-methyl-propan-1-one, phenyl α-hydroxyalkylphenone compounds such as glyoxylic acid methyl ester; 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane- 1-one,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butanone-1-one,2-(dimethylamino)-2-[ α-aminoalkylphenone compounds such as (4-methylphenyl)methyl]-1-[4-(4-molformyl)phenyl]-1-butanone; acylphosphine oxide compounds such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide; 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime), etc. Tanone 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyloxime) and other oxime ester compounds; Benzophenone 4 Benzophenone compounds such as phenylbenzophenone, isophthalphenone, and 4-benzoyl-4'-methyl-diphenyl sulfide; 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis(trichloromethyl)-s-triazine, 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-tolyl)-4,6-bis(trichloromethyl)-s-triazine, 2-piperonyl-4,6-bis(trichloromethyl)-s-triazine, 2,4-bis(bi) Examples include triazine compounds such as su(trichloromethyl)-6-styryl-s-triazine, 2-(naphtho-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxynaphtho-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2,4-trichloromethyl-(piperonyl)-6-triazine, or 2,4-trichloromethyl-(4'-methoxystyryl)-6-triazine.

[0072] Commercially available products include α-hydroxyalkylphenone compounds such as Omnirad 127, 184, 1173, and 2959 from IGM Resins; aminoalkylphenone compounds such as Omnirad 907, 369E, and 379EG from IGM Resins; acylphosphine oxide compounds such as Omnirad 819 and TPO from IGM Resins; oxime ester compounds such as IRGACURE OXE-01, 02, 03, 04, and 05 from BASF Japan; ADEKA Arcules N-1919, NCI-730, 831E, and 930 from ADEKA; and TRONLY TR-PBG-301, 304, 305, 309, 314, 345, 358, 380, 365, 610, 3054, and 3057 from Changzhou Strong New Materials Co., Ltd. Examples include Omnirad 1312, 1314, and 1316 from Resins, SPI-02, 03, 04, 05, 06, and 07 from Samyang Corporation, and DFI-020, 306, and EOX-01 from Daito Chemix.

[0073] In particular, acylphosphine compounds and / or oxime ester compounds are preferred from the viewpoint of curability and suppression of surface foreign matter.

[0074] (Acylphosphine compounds) Examples of acylphosphine compounds include monoacylphosphine oxides and bisacylphosphine oxides. Examples of monoacylphosphine oxides, though not particularly limited, include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-triethylbenzoyldiphenylphosphine oxide, and 2,4,6-triphenylbenzoyldiphenylphosphine oxide. Examples of bisacylphosphine oxides, though not particularly limited, include bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide and bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide. Examples of commercially available acylphosphine compounds include Omnirad TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide), Omnirad 819 (bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide), and Omnirad TPOL (ethyl(2,4,6-trimethylbenzoyl)-phenylphosphenate).

[0075] (Oxime ester compounds) Oxime ester compounds undergo cleavage of the oxime's NO bond upon absorption of ultraviolet light, generating iminyl radicals and alkyloxy radicals. These radicals further decompose to produce highly reactive radicals, allowing the ink to cure with less exposure. Oxime ester compounds have high quantum efficiency, resulting in a highly curable coating film with fewer impurities.

[0076] Examples of oxime ester compounds include those described in Japanese Patent Publication No. 2007-210991, Japanese Patent Publication No. 2009-179619, Japanese Patent Publication No. 2010-037223, Japanese Patent Publication No. 2010-215575, Japanese Patent Publication No. 2011-020998, International Publication No. 2021 / 175855, etc.

[0077] The polymerization initiator (D) content is preferably 1 to 15% by mass, and more preferably 3 to 10% by mass, in the UV-curable inkjet composition. Adding an appropriate amount further improves photocurability.

[0078] <Solvent> To reduce the viscosity of the UV-curable inkjet composition and improve its wettability on the substrate, a small amount of solvent may be included in the UV-curable inkjet composition. The solvent is selected considering the solubility of each component of the UV-curable inkjet composition, as well as safety. From the viewpoint of curability, the solvent content should be 5.0% by mass or less in the UV-curable inkjet composition. From the viewpoint of ejection stability, it is preferably 0.2 to 5.0% by mass, more preferably 0.5 to 4.0% by mass.

[0079] The boiling point of the solvent is preferably 120°C to 300°C, and more preferably 140°C to 270°C. Preferred solvents include glycol compounds such as monoacetates, diacetates, diols, monoalkyl ethers, and dialkyl ethers, as well as lactic acid esters. Among these, glycol compounds such as monoacetates, monoalkyl ethers, and dialkyl ethers are preferred. More specifically, tetraethylene glycol dialkyl ether, ethylene glycol monobutyl ether acetate, and diethylene glycol diethyl ether are preferred.

[0080] <Sensitizer> The UV-curable inkjet composition of the present invention may contain a sensitizer. Examples of sensitizers include chalcone derivatives, unsaturated ketones such as dibenzalacetone, 1,2-diketone derivatives such as benzyl and camphorquinone, benzoin derivatives, fluorene derivatives, naphthoquinone derivatives, anthraquinone derivatives, xanthene derivatives, thioxanthene derivatives, xanthone derivatives, thioxanthone derivatives, coumarin derivatives, ketocoumarin derivatives, cyanine derivatives, merocyanine derivatives, polymethine dyes such as oxonol derivatives, acridine derivatives, azine derivatives, thiaidine derivatives, oxazine derivatives, indoline derivatives, azulene derivatives, azulenium derivatives, squarylium derivatives, porphyrin derivatives, tetraphenylporphyrin derivatives, triarylmethane derivatives, tetrabenzoporphyrin derivatives, and tetrapyradinoporphyrazine derivatives. Examples include phthalocyanine derivatives, tetraazaporphyrazine derivatives, tetraquinoxaliloporphyrazine derivatives, naphthalocyanine derivatives, subphthalocyanine derivatives, pyrylium derivatives, thiopyrillium derivatives, tetraphylline derivatives, annulene derivatives, spiropyran derivatives, spirooxazine derivatives, thiospilopyran derivatives, metal arene complexes, organic ruthenium complexes, or Michler ketone derivatives, α-acyloxyesters, acylphosphine oxides, methylphenylglyoxylates, benzyl, 9,10-phenanthrenequinone, camphorquinone, ethyl anthraquinone, 4,4'-diethylisophthalophenone, 3,3' or 4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 4,4'-bis(diethylamino)benzophenone, and the like.

[0081] Among the sensitizers mentioned above, thioxanthone derivatives, Michler ketone derivatives, and carbazole derivatives are particularly suitable for sensitizing. More specifically, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-dichlorothioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 1-chloro-4-propoxythioxanthone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(ethylmethylamino)benzophenone, N-ethylcarbazole, 3-benzoyl-N-ethylcarbazole, 3,6-dibenzoyl-N-ethylcarbazole, etc., can be used.

[0082] More specifically, examples of sensitizers include, but are not limited to, those described in "Pigment Handbook" (1986, Kodansha) edited by Shin Okawara et al., "Chemistry of Functional Pigments" (1981, CMC) edited by Shin Okawara et al., and "Special Functional Materials" (1986, CMC). In addition, sensitizers that exhibit absorption in the ultraviolet to near-infrared region can also be included. Sensitizers can be used alone or in combination of two or more types. The sensitizer content is preferably 3 to 60 parts by mass, and more preferably 5 to 50 parts by mass, per 100 parts by mass of polymerization initiator (D). Including an appropriate amount further improves curability and the surface condition of the coating film.

[0083] <Polymerization inhibitor> The UV-curable inkjet composition of the present invention may use polymerization inhibitors to enhance viscosity stability over time, ejection stability after time, and viscosity stability within the inkjet recording device. Hindered phenol compounds, phenothiazine compounds, hindered amine compounds, and phosphorus compounds are particularly preferred as polymerization inhibitors. Specifically, examples include 4-methoxyphenol, hydroquinone, methylhydroquinone, t-butylhydroquinone, 2,6-di-t-butyl-4-methylphenol, phenothiazine, and aluminum salts of N-nitrosophenylhydroxylamine. From the viewpoint of enhancing stability over time while maintaining curability, it is preferable to incorporate the polymerization inhibitor at a ratio of 0.01 to 2% by mass of the total UV-curable inkjet composition.

[0084] <Antioxidant> The UV-curable inkjet composition of the present invention may contain an antioxidant. The antioxidant prevents the polymerization initiator (D) contained in the UV-curable inkjet composition from oxidizing and yellowing, thereby improving the transmittance of the coating film.

[0085] Examples of antioxidants include hindered phenol, hindered amine, phosphorus, sulfur, and hydroxylamine compounds. In this invention, it is preferable that the antioxidant is a compound that does not contain halogen atoms.

[0086] Among these, hindered phenol-based antioxidants, hindered amine-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants are preferred from the viewpoint of achieving both the transmittance and sensitivity of the coating film.

[0087] Antioxidants can be used alone or in combination of two or more types.

[0088] The antioxidant content is more preferable when it is 0.5 to 5.0% by mass of 100% by mass of the solid content of the UV-curable inkjet composition, as this results in good transmittance and spectral characteristics.

[0089] <Surface modifier> The ultraviolet-curable inkjet composition of the present invention may contain a surface modifier. As used herein, a surface modifier refers to a substance that, when added, reduces the surface tension of the ultraviolet-curable inkjet composition. Examples of surface modifiers include silicone-based surface modifiers, fluorine-based surface modifiers, acrylic-based surface modifiers, and acetylene glycol-based surface modifiers. From the viewpoint of surface tension reduction ability and compatibility with polymerizable compounds, the use of a silicone-based surface modifier is preferred.

[0090] Specific examples of silicone-based surface modifiers include modified dimethylsiloxane skeletons. Among these, polyether-modified siloxane-based surface modifiers are preferred. Polyethers may be, for example, polyethylene oxide and polypropylene oxide. In one embodiment of the present invention, commercially available polyether-modified silicone surfactants can be used. Examples of representative products that can be preferably used include polyether-modified siloxanes such as BYK(registered trademark-378, 348, and 349) from Bic Chemie; and Examples include polyether-modified polydimethylsiloxanes such as BYK-UV3500 and UV3510. Also, examples include polyether-modified siloxane copolymers such as TEGO® GLIDE 450, 440, 435, 432, 410, 406, 130, 110, and 100 from Evonik Degussa. Among these, polyether-modified silicone-based surface modifiers such as BYK-331, 378, 348, UV3510, TEGO GLIDE 450, 440, 432, and 410 are preferred from the viewpoint of forming good image quality.

[0091] The content of the silicone-based surface modifier is preferably in the range of 0.1 to 5.0% by mass relative to the total weight of the UV-curable inkjet composition. By setting the content to 0.1% by mass or more, the wettability of the UV-curable inkjet composition to the substrate can be easily improved. On the other hand, by setting the content to 5.0% by mass or less, it becomes easier to ensure the storage stability of the UV-curable inkjet composition.

[0092] <Storage stabilizer> The UV-curable inkjet composition of the present invention may contain a storage stabilizer to stabilize the viscosity of the composition over time. Examples of storage stabilizers include benzyl trimethyl chloride, quaternary ammonium chlorides such as diethylhydroxyamine, organic acids such as lactic acid and oxalic acid and their methyl ethers, organic phosphines such as t-butyl pyrocatechol, tetraethylphosphine, and tetraphenylphosphine, and phosphates. The storage stabilizer can be used in an amount of 0.1 to 10% by mass, based on the total amount of the colorant (A) (100% by mass).

[0093] <Other ingredients> The ultraviolet-curable inkjet composition of the present invention may contain other components besides those listed above. Examples of other components include binder resins, thermal crosslinking agents, curing agents, curing accelerators, acid generators, curing catalysts, chain transfer agents, silane coupling agents, and near-infrared absorbers. The content of these other components can be appropriately set within a range that solves the problems of the present invention.

[0094] <Method for preparing UV-curable inkjet compositions> The UV-curable inkjet composition of the present invention can be prepared by further diluting a colorant dispersion, which is produced by finely dispersing a colorant carrier such as a colorant (A), resin (B), and polymerizable compound (C) using various dispersion methods such as a kneader, two-roll mill, three-roll mill, ball mill, horizontal sand mill, vertical sand mill, annular bead mill, or attritor, with a polymerizable compound (C), polymerization initiator (D), etc. When preparing the colorant dispersion, two or more colorants may be dispersed simultaneously on the colorant carrier, or they may be dispersed separately on the colorant carrier and then mixed. If the colorant has high solubility, such as a dye, specifically if it has high solubility in the polymerizable compound (C) used and dissolves upon stirring without the presence of foreign matter, then it is not necessary to produce it by fine dispersion as described above.

[0095] <Water content> From the viewpoint of stability, the UV-curable inkjet composition of the present invention preferably contains 2.0% by mass or less of water.

[0096] The water content in the UV-curable inkjet composition is more preferably 1.5% by mass or less, and particularly preferably 1.0% by mass or less. Furthermore, the lower limit of the water content is preferable as much as possible, but there are no particular restrictions.

[0097] There are no particular restrictions on the method for controlling the water content, and known methods can be used. For example, each of the above-mentioned components can be thoroughly dried to reduce the amount of water contained in the components before use. Another example is a method of producing an ultraviolet-curable inkjet composition while blowing in dry air, an inert gas, or a mixture thereof.

[0098] <Specific metal atoms> The UV-curable inkjet composition of the present invention may contain small amounts of metal components, including Li, Na, Mg, K, Cs, Co, Ca, Fe, Si, and Zr (hereinafter also referred to as specific metal atoms), in addition to the components of the colorant (A), resin (B), polymerizable compound (C), and polymerization initiator (D). If a large amount of these metal components containing specific metal atoms is present, storage stability may be impaired, heat resistance may decrease, and ejection performance may deteriorate. Furthermore, color filters made using UV-curable inkjet compositions containing a large amount of metal components, including such specific metal atoms, may generate foreign matter, which can easily lead to a decrease in transmittance. Preferably, the total content of specific metal atoms in the metal components of the UV-curable inkjet composition of the present invention is 1 to 1000 ppm by mass relative to the entire UV-curable inkjet composition.

[0099] <Average dispersed particle size> The average dispersed particle diameter (secondary particle diameter) of particles in the UV-curable inkjet composition is preferably 10 to 200 nm, and more preferably 30 to 150 nm. Having an appropriate particle diameter makes it easier to obtain a UV-curable inkjet composition with high dispersion stability.

[0100] The method for measuring the average dispersed particle diameter (secondary particle diameter) uses, for example, Nikkiso's Microtrac UPA-EX150, which employs dynamic light scattering (FFT power-spectrum method), with particle permeability set to absorption mode, particle shape to non-spherical, and D50 particle diameter as the average diameter. The diluent solvent used for measurement is the same solvent used for dispersion, and it is preferable to measure immediately after sample preparation of ultrasonically treated samples to obtain results with less variation.

[0101] <Removal of coarse particles> It is preferable to remove coarse particles of 5 μm or larger, preferably 1 μm or larger, more preferably 0.5 μm or larger, and any mixed dust from the UV-curable inkjet composition by means of centrifugal separation, sintering filters, or membrane filters. The UV-curable inkjet composition of the present invention preferably contains substantially no particles of 0.5 μm or larger, and more preferably contains no particles of 0.3 μm or smaller.

[0102] <Viscosity> The UV-curable inkjet composition of the present invention preferably has a viscosity of 10 mPa·s to 40 mPa·s at 25°C. A viscosity within this range provides excellent ejection responsiveness and stability.

[0103] <Cured film> The cured film of the present invention is formed by the ultraviolet-curable inkjet composition of the present invention. The cured film may be used in a laminated state on a substrate, or the cured film may be peeled off from the substrate. The method for manufacturing the cured film is not particularly limited, and known methods can be used. For example, the ultraviolet-curable inkjet composition of the present invention can be printed on a substrate using the printing method described later to manufacture the film.

[0104] Examples of substrates include those made of materials such as glass, resin, and silicon. An organic light-emitting layer may be formed on these substrates. An image sensor such as a CCD or CMOS may also be formed on the substrate. Furthermore, a primer layer may be provided on the substrate as needed to improve adhesion with the upper layer, prevent diffusion of materials, and flatten the substrate surface.

[0105] <Printing method> The ultraviolet-curable inkjet composition of the present invention has excellent curability and can therefore be used in a single-pass printing method. A single-pass printing method includes, for example, an ink ejection mechanism having one or more inkjet heads, a mechanism for transporting the substrate on which the ink has landed at a desired speed, and a mechanism for curing the composition by irradiating it with active energy rays such as a UV lamp or electron beam.

[0106] The optimal film thickness is preferably 2 μm to 20 μm, more preferably 3 μm to 15 μm, and even more preferably 4 μm to 10 μm. Within this range, good color development and excellent curing properties are obtained.

[0107] (Inkjet head) In inkjet printing, the inkjet head used may be either on-demand or continuous. Furthermore, specific examples of ejection methods include electromechanical conversion methods (e.g., single-cavity type, double-cavity type, bender type, piston type, shear-mode type, shear-wall type, etc.), electro-thermal conversion methods (e.g., thermal inkjet type, bubble jet (registered trademark) type, etc.), electrostatic attraction methods (e.g., electric field control type, slit jet type, etc.), and discharge methods (e.g., spark jet type, etc.). Any of these ejection methods may be used.

[0108] (Ink droplet size) The volume of ink droplets ejected from the inkjet head is preferably in the range of 0.5 to 100 pL. More preferably, it is in the range of 2 to 20 pL, from the viewpoint of minimizing uneven coating and enabling high printing speeds.

[0109] (Printing method) There are two main inkjet printing methods: one-pass printing and multi-pass printing. One-pass printing involves fixing multiple inkjet heads in a predetermined printing area and printing with a single head scan. In contrast, multi-pass printing (also known as serial printing) involves printing a predetermined printing area with multiple head scans.

[0110] In a single-pass printing method, it is preferable to use a wide head in which nozzles are arranged in a width greater than or equal to the width of the desired coating pattern. When forming multiple independent coating patterns on the same substrate that are not continuous with each other, it is sufficient to use a wide head that is at least greater than the width of each coating pattern.

[0111] The active energy ray used to cure the inkjet composition can be any ultraviolet light that can affect the electron orbitals of the irradiated object and induce polymerization reactions such as radicals, cations, and anions.

[0112] Specific examples of ultraviolet light sources that can be used include high-pressure mercury lamps, metal halide lamps, low-pressure mercury lamps, ultra-high-pressure mercury lamps, ultraviolet lasers, LEDs, and sunlight. From the standpoint of convenience and cost, it is preferable to use high-pressure mercury lamps, metal halide lamps, and LEDs. The emission maximum wavelength is preferably 200 to 600 nm, more preferably 300 to 450 nm, even more preferably 320 to 420 nm, and particularly preferably ultraviolet light in the range of 340 to 400 nm.

[0113] <Color Filter> The color filter of the present invention comprises a substrate and a cured film of the present invention. The color filter of the present invention comprises at least one red filter segment, at least one green filter segment, and at least one blue filter segment. Furthermore, in addition to the above three color filter segments, it may also comprise a yellow filter segment.

[0114] <How to manufacture color filters> The color filter of the present invention can be manufactured by printing.

[0115] The formation of filter segments by printing is a low-cost and highly mass-producible method for manufacturing color filters, as patterns can be created by printing UV-curable inkjet compositions. Furthermore, advancements in printing technology enable the printing of fine patterns with high dimensional accuracy and smoothness. Controlling the fluidity of the composition on the printing press is also important, and the viscosity of the composition can be adjusted using dispersants and extender pigments.

[0116] <Solid-state image sensor> The solid-state image sensor of the present invention comprises the color filter of the present invention. The form used in the solid-state image sensor is not particularly limited, but for example, it may have a substrate on which a plurality of photodiodes constituting the light-receiving area of ​​the solid-state image sensor (CCD image sensor, CMOS image sensor, etc.) and transfer electrodes made of polysilicon or the like are provided, a light-shielding film with an opening only for the light-receiving portion of the photodiode is provided on the photodiode and transfer electrodes, a device protective film made of silicon nitride or the like is provided on the light-shielding film so as to cover the entire surface of the light-shielding film and the light-receiving portion of the photodiode, and a filter on the device protective film. Furthermore, it may have a configuration in which a light-gathering means (e.g., a microlens, etc.; the same applies hereinafter) is provided on the device protective film below the filter (closer to the substrate), or a configuration in which the light-gathering means is provided on the filter. The filter may also have a structure in which a hardened film forming each colored pixel is embedded in a space partitioned, for example, in a grid pattern by partitions. In this case, it is preferable that the partitions have a low refractive index with respect to each colored pixel. The imaging device equipped with the solid-state image sensor of the present invention can be used in a variety of applications, such as digital cameras, electronic devices with imaging functions (smartphones, tablet terminals, etc.), in-vehicle cameras, surveillance cameras, and optical sensors.

[0117] <Image display device> The image display device of the present invention comprises the color filter of the present invention. Examples of image display devices include liquid crystal displays and organic EL displays. The form in which it is used in the image display device is not particularly limited, but it can be used as a color filter, black matrix, light-shielding filter, infrared cut filter, or infrared transmission filter. The form used in the image display device is not particularly limited, as long as it functions as an image display device. For example, the configuration described in "Next-Generation Liquid Crystal Display Technology" (by Tatsuo Uchida, published by Kogyo Chosakai Co., Ltd. in 1994) is one such example. For definitions of image display devices and details of various image display devices, see, for example, "Electronic Display Devices" (by Akio Sasaki, Kogyo Chosakai Co., Ltd., published in 1990) and "Display Devices" (by Junsho Ibuki, Sangyo Tosho Co., Ltd., published in 1989). [Examples]

[0118] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples. Note that "parts" refers to "parts by mass" and "%" refers to "percentage by mass".

[0119] (Average primary particle size of pigments) The average primary particle size of the manufactured pigment composition was measured (calculated) using the following method. The average primary particle size of the pigment was measured by directly measuring the size of the primary particles from electron microscope images using a transmission electron microscope (TEM). Specifically, the average of approximately 200 arbitrarily selected particles was used as the particle size of the pigment's primary particles. If a particle had a long axis and a short axis, the length of the long axis was used.

[0120] [Manufacturing Example 1] <Manufacturing of micronized pigments> (Manufacturing of finely milled green pigment (PG36-1)) 200 parts of phthalocyanine-based green pigment CI Pigment Green 36 (CLARIANT's "Green8G"), 1400 parts of sodium chloride, and 360 parts of diethylene glycol were charged into a stainless steel 1-gallon kneader (Inoue Seisakusho Co., Ltd.) and kneaded at 80°C for 6 hours. Next, this mixture was added to 8000 parts of warm water and stirred for 2 hours while heating to 70°C to form a slurry. After filtering and repeatedly washing with water to remove sodium chloride and diethylene glycol, the slurry was dried at 85°C overnight to obtain finely ground green pigment (PG36-1).

[0121] [Manufacturing Examples 2-5] (Manufacturing of finely milled green pigment (PG36-2~5)) In the production of the finely milled green pigment (PG36-1), the same procedure as in the production of the finely milled green pigment (PG36-1) was performed, except that the mixing temperature and mixing time were changed to the conditions listed in Table 1, to obtain the finely milled green pigments (PG36-2) to (PG36-5), respectively. Table 1 shows the average primary particle size of the obtained refined green pigment.

[0122] [Table 1]

[0123] [Manufacturing Example 6] (Manufacturing of finely milled yellow pigment (PY231-1)) 200 parts of quinophthalone-based yellow pigment CI Pigment Yellow 231, 1400 parts of sodium chloride, and 360 parts of diethylene glycol were charged into a stainless steel 1-gallon kneader (manufactured by Inoue Seisakusho Co., Ltd.) and kneaded at 80°C for 6 hours. Next, this mixture was added to 8 liters of warm water and stirred for 2 hours while heating to 80°C to form a slurry. After filtering and repeatedly washing with water to remove sodium chloride and diethylene glycol, the slurry was dried at 85°C overnight to obtain finely ground yellow pigment (PY231-1).

[0124] [Manufacturing Examples 7-13] (Manufacturing of finely milled yellow pigment (PY150-1), finely milled yellow pigment (PY138-1), finely milled yellow pigment (PY139-1), finely milled yellow pigment (PY185-1), finely milled red pigment (PR177-1), finely milled blue pigment (PB15:6-1), manufacturing of finely milled blue pigment (PB15:3-1)) In the production of the finely milled yellow pigment (PY231-1), the same procedure as in the production of the finely milled yellow pigment (PY231-1) was performed, except that CI Pigment Yellow 231 was replaced with the pigments listed in Table 2, thereby obtaining finely milled yellow pigment (PY231-1), finely milled yellow pigment (PY138-1), finely milled yellow pigment (PY139-1), finely milled yellow pigment (PY185-1), finely milled red pigment (PR177-1), finely milled blue pigment (PB15:6-1), and finely milled blue pigment (PB15:3-1). Table 2 shows the average primary particle size of each refined pigment.

[0125] [Table 2]

[0126] <Manufacturing of pigment dispersions> [Manufacturing Example 14] (Production of pigment dispersion (d-1)) A pigment dispersion (d-1) was prepared by uniformly stirring and mixing a mixture of the following compositions using a high-speed mixer or the like, and then dispersing the resulting mill base in a horizontal sand mill for approximately one hour. Finely milled green pigment (PG36-1) 11.7 parts Pigment derivative (B1) 1.3 parts SP32000 7.8 parts Dipropylene glycol diacrylate 44.2 parts

[0127] [Manufacturing Examples 15-29] (Manufacturing of pigment dispersions (d-2) to (d-16)) Pigment dispersions (d-2) to (d-16) were produced by following the same procedure as for the production of pigment dispersion (d-1), except that the composition and amount of the colorant (A), pigment derivative, dispersant, and polymerizable compound (C) were changed as shown in Table 3.

[0128] [Table 3]

[0129] <Pigment derivatives> [ka] <Dispersant> • "SP32000"; Basic pigment dispersion resin "Solspers 32000" (manufactured by Lubrizol Japan Co., Ltd.) <Polymerizable compound (C)> • DPGDA: Dipropylene glycol diacrylate, manufactured by BASF as "Laromer DPGDA" (Viscosity at 25°C: 8.0 mPa·s) • VEEA: 2-(2-vinyloxyethoxy)ethyl acrylate, manufactured by Nippon Shokubai Co., Ltd. (Viscosity at 25°C: 3.7 mPa·s) • IBXA: Isovonyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd. (viscosity 7.7 mPa·s at 25°C) • BZA: Benzyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd., "Viscoat #160" (Viscosity at 25°C: 2.2 mPa·s)

[0130] <Manufacturing of UV-curable inkjet compositions> [Example 1] (UV-curable inkjet composition (D-1)) To achieve the formulations shown in Table 4, a mixture of polymerizable compound, polymerization initiator, and stabilizer was slowly added to the previously prepared pigment dispersion, and the resulting mixture was stirred. Next, a surface tension modifier was added to the mixture, and it was shaken in a shaker for 6 hours. The composition was then filtered through a PTFE filter with a pore diameter of 0.5 microns to remove dust and coarse particles, and ultraviolet-curable inkjet composition (D-1) was obtained. Note that the order in which the raw materials are added and mixed to obtain the above mixture may not be significant.

[0131] [Examples 2-25, Comparative Examples 1-27] (UV-curable inkjet compositions (D-2) to (D-52)) Except for the material types and masses listed in Table 4, ultraviolet-curable inkjet compositions (D-2) to (D-52) were manufactured in the same manner as the ultraviolet-curable inkjet compositions.

[0132] [Table 4]

[0133] <Polymerizable compound (C)> • DPHA: Dipentaerythritol pentaacrylate and hexaacrylate, manufactured by Toagosei Co., Ltd. as "Aronics M-402" (Solid at 25°C) <Polymerization initiator (D)> • Omnirad819: Manufactured by IGM Resins, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide • Omnirad369: Manufactured by IGM Resins, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 • IlgaCure OXE-04: Manufactured by BASF Japan • D-1: The following compounds [ka] ·D-2: The following compounds [ka] <Surface modifier> • BYK-UV3510: Manufactured by BYK Chemie, polyether-modified polydimethyl sulfide Roxan <solvent> • DEDG: Diethylene glycol diethyl ether • Butycel acetate: Ethylene glycol monobutyl ether acetate

[0134] <Evaluation method for UV-curable inkjet compositions> The UV-curable inkjet compositions prepared in each example and comparative example were printed using a single-pass inkjet printer (OnePass Jet, manufactured by Tritech Co., Ltd.) equipped with an inkjet ejection mechanism featuring a Kyocera head (KJ4A), a mechanism for transporting the ink-deposited substrate at a desired speed, and a mechanism for subsequent irradiation with a UV lamp. The print conditions were 14 pl of ink droplets and 600 × 600 dpi, and various characteristics were evaluated. An experimental 385 nm UV-LED irradiator (manufactured by CCS Corporation) was used as the exposure device, with an exposure energy of 1000 mJ / cm². 2 The film was cured by irradiation under the specified exposure conditions, and a sample of the cured film was prepared. The printing speed and printed image were changed for each performance evaluation.

[0135] (Initial viscosity, storage stability) The obtained UV-curable inkjet composition was measured for viscosity using an E-type viscometer (ELD-type viscometer manufactured by Toki Sangyo Co., Ltd.) at 25°C and a rotation speed of 20 rpm, and this was defined as the initial viscosity. Furthermore, an accelerated aging test was performed at 60°C for two weeks, and the accelerated viscosity over time was measured. The rate of change due to accelerated aging was calculated as accelerated viscosity over time / initial viscosity, and evaluated according to the following criteria. ◎: Change rate less than 5% ○: Change rate of 5% or more but less than 10% △: Change rate between 10% and less than 20% ×: Change rate of 20% or more

[0136] (coloring power) A UV-curable inkjet composition was printed onto a 100mm x 100mm, 0.5mm thick glass substrate using an inkjet printer to obtain cured films with the following chromaticities for each color under a C light source. The film thickness of the obtained cured films was measured using a surface shape measuring device "Dektak8 (manufactured by Veeco)". Evaluation was performed according to the following criteria. The thinner the film thickness, the higher the coloring power. ≪Chromaticity≫ GREEN :y=0.420 YELLOW: x = 0.440 RED:x=0.640 BLUE: y=0.105 ◎: Film thickness less than 6.0 μm ○: Film thickness of 6.0 μm or more, and less than 8.0 μm. △: Film thickness is 8.0 μm or more, but less than 10.0 μm. ×: Film thickness is 10.0 μm or more

[0137] (filtration) Twenty parts of the obtained UV-curable inkjet composition were passed through a filter (φ1.0 μm, manufactured by Whatman, GLASS MICROFIBER FILTERS) under nitrogen pressure (0.3 MPa), and the mass that could be filtered was measured and evaluated according to the following criteria. ◎: Filtration volume of 15.0 parts or more (good) ○: Filtration volume is 10.0 parts or more but less than 15.0 parts (practical) ×: Filtration volume is less than 10.0 parts (not practical)

[0138] (Surface foreign matter) A sample of the hardened film was obtained by printing the evaluation ink onto a 1.1 mm thick glass substrate using an inkjet printer. The conveyor speed was set to 35 m / min. Subsequently, the surface of the obtained sample was observed. For evaluation, an Olympus Systems BX60 metal microscope was used to observe the surface at a magnification of 500x using transmission, and the number of foreign matter was measured in five arbitrary fields and evaluated according to the following criteria. Note that ◎ indicates an excellent level, ○ indicates a good level, △ indicates a usable level, and × indicates a level unsuitable for practical use. ◎: Number of foreign objects is less than 10 ○: Number of foreign objects is 10 or more but less than 20. △: Number of foreign objects is 20 or more but less than 60. ×: More than 60 foreign objects

[0139] [Table 5]

[0140] As shown in Table 5, Examples 1-25 exhibited high coloring power, low viscosity, good storage stability, excellent filterability, and minimal surface impurities when a cured film was formed.

[0141] [Examples 101-140] (UV-curable inkjet compositions (DD-1) to (DD-40)) To achieve the formulations described in Tables 6-1 to 6-4, a mixture of polymerizable compound, photopolymerization initiator, and polymerization inhibitor was slowly added to the previously prepared pigment dispersion, and the resulting mixture was stirred. Next, a surface tension modifier was added to the mixture, and the mixture was shaken in a shaker for 6 hours to prepare UV-curable inkjet compositions (DD-1) to (DD-40). The obtained UV-curable inkjet compositions were filtered through a PTFE filter with a pore diameter of 0.5 microns to remove dust and coarse particles, and used as evaluation inks. Note that the order in which the raw materials are added and mixed to obtain the above mixtures does not matter. Also, the content of the colorant in the ultraviolet curable inkjet compositions (DD-1) to (DD-40) is 13% by mass in the ultraviolet curable inkjet composition.

[0142]

Table 6-1

[0143]

Table 6-2

[0144]

Table 6-3

[0145]

Table 6-4

[0146] <Evaluation of Ultraviolet Curable Inkjet Composition> The obtained ultraviolet curable inkjet compositions (DD-1) to (DD-40) were evaluated in the same manner as the ultraviolet curable inkjet compositions (D-1) to (D-52). The test results are shown in Tables 7-1 to 7-4.

[0147]

Table 7-1

[0148]

Table 7-2

[0149]

Table 7-3

[0150]

Table 7-4

[0151] The results in Tables 7-1 to 7-4 show that even with high coloring power, the viscosity was low, storage stability was good, and furthermore, the filterability was excellent, and there was little surface foreign matter when a cured film was formed.

[0152] A color filter was created by printing with the ultraviolet-curable inkjet composition of the present invention. Due to its excellent properties, the resulting color filter is expected to be suitably used in solid-state image sensors, image display devices, and the like.

Claims

1. A UV-curable inkjet composition for color filters comprising a colorant (A), a resin (B), a polymerizable compound (C), and a polymerization initiator (D), The coloring agent (A) comprises at least one selected from isoindoline pigments, azo metal complex pigments, quinophthalone pigments, diketopyrrolopyrrole pigments, and anthraquinone pigments. The content of colorant (A) is 9.0% by mass or more and 16.0% by mass or less in the UV-curable inkjet composition. The polymerizable compound (C) comprises a monofunctional and / or bifunctional monomer (C1) having a viscosity of 10 mPa·s or less at 25°C. A UV-curable inkjet composition for color filters, wherein the content of a monofunctional or / or bifunctional monomer (C1) is 90% by mass or more and 100% by mass or less in a polymerizable compound (C).

2. The ultraviolet-curable inkjet composition for color filters according to claim 1, wherein the viscosity at 25°C is 10 mPa·s or more and 40 mPa·s or less.

3. The ultraviolet-curable inkjet composition for color filters according to claim 1, wherein the coloring agent (A) contains a pigment, and the particle size of the pigment is 50 to 150 nm or less.

4. The ultraviolet-curable inkjet composition for color filters according to claim 1, wherein the polymerization initiator (D) comprises an acylphosphine compound and / or an oxime ester compound.

5. A cured film formed by an ultraviolet-curable inkjet composition for color filters according to any one of claims 1 to 4.

6. A color filter having a substrate and the cured film described in claim 5.

7. A solid-state image sensor comprising the color filter described in claim 6.

8. An image display device comprising the color filter described in claim 6.

Images