Squarylium color material, color material dispersion, ink composition, optical filter, and display device

Abstract

To provide a squarylium color material having excellent heat resistance and light resistance, and a color material dispersion, an ink composition, an optical filter, and a display device each containing the squarylium color material.SOLUTION: A squarylium color material comprises a salt-forming compound of a squarylium dye represented by general formula (1) and a heteropoly acid.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a squarylium colorant, a colorant dispersion, an ink composition, an optical filter, and a display device. [Background technology]

[0002] In recent years, LEDs have been increasingly used as light sources for lighting devices and display devices. For example, there are several types of light emission methods, including a method in which LEDs that emit R (red), G (green), and B (blue) light are arranged to obtain white light, a method in which white light is obtained by combining blue light from a blue LED with yellow light emitted from a yellow phosphor, and a method in which white light is obtained by combining blue light from a blue LED with light emitted from red and green phosphors. When using one of these methods to obtain white light by combining a blue LED with a phosphor, the spectrum of the obtained white light contains light that shows an orange color in the region around 590 nm, and it is known that the color rendering decreases when the emission intensity of light in this region is high. Moreover, these issues are also the same when organic electroluminescence is used as the light source for lighting devices and display devices.

[0003] For this reason, conventionally, an optical filter is installed in front of a display device to remove unnecessary luminescent components and make the display color clear, and a dye compound that selectively absorbs light in an unnecessary wavelength range is used. The dye compound that selectively absorbs light in an unnecessary wavelength range and is used in such an optical filter is further required to have both light resistance and heat resistance.

[0004] Patent Document 1 describes that a salt-forming compound of an organic dye and a heteropolyacid, a colorant dispersion and a composition using the same, and a film and an optical filter using the same have excellent light resistance. Patent Document 2 describes that by converting a squarylium dye represented by general formula (1) having a specific structure into a salt-forming compound with a heteropolyacid, a squarylium colorant having good light fastness and reduced absorption (side absorption) at wavelengths different from the maximum absorption wavelength can be obtained. Patent Document 3 describes that a film having good light resistance and suppressed side absorption can be obtained by using a colorant containing a colorless organic cation added thereto when forming a salt of a squarylium dye with a heteropolyacid. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 216282 [Patent Document 2] Patent Publication No. 2023-006190 [Patent Document 3] Patent Publication No. 2023-006191 Summary of the Invention [Problem to be solved by the invention]

[0006] In order to suppress light in unnecessary wavelength regions caused by light sources, optical members, or external light reflection, it is considered effective to use a dye compound that selectively absorbs light in unnecessary wavelength regions. However, the squarylium color materials disclosed in Patent Documents 1 to 3 may have insufficient light fastness and heat resistance, and further improvements in light fastness and heat resistance are desired.

[0007] The present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a squarylium colorant having excellent heat resistance and light fastness, and a colorant dispersion, an ink composition, an optical filter, and a display device containing the squarylium colorant. [Means for solving the problem]

[0008] The present inventors used indole as a skeleton that is stable to heat and light, and synthesized a squarylium dye in which indole is directly bonded to a squaric acid moiety. They found that a salt-forming compound of the squarylium dye and a heteropolyacid has excellent heat resistance and light resistance. The present disclosure includes the following aspects. <1> A squarylium colorant comprising a squarylium dye represented by the following general formula (1) and a salt-forming compound of a heteropolyacid.

[0009] [ka] (In formula (1), R 1 ~R 8 each independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, -OR 10 , -OCOR 11 , -COOR 12 , -COR 13 , -NR 14 R 15 , -NHCOR 16 , -CONR 17 R 18 , -NHCONR 19 R 20 , -NHCOOR 21 , -SR 22 , -SO2R 23 , -SO2OR 24 , -NHSO2R 25 , -SO2NR 26 R 27 , -(R 28 O) n’ R 29 R represents a heterocyclic group or a hydrocarbon group which may have a substituent, and adjacent substituents may be linked to each other to form a ring. 10 ~R 12 and R 21 ~R 25 R each independently represents a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. 13 ~R 20 , R 26 ~R 27 and R 29 R each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. 28 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms. n' represents an integer of 1 to 18. Each X independently represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. Each Y independently represents a divalent organic group; 0 each independently represents a group that can be derived to an organic cationic group or an organic cationic group.

[0010] <2> A squarylium colorant comprising a squarylium dye represented by the following general formula (2) and a salt-forming compound of a heteropolyacid.

[0011] [ka] (In formula (2), R 1 ~R 8 each independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, -OR 10 , -OCOR 11 , -COOR 12 , -COR 13 , -NR 14 R 15 , -NHCOR 16 , -CONR 17 R 18 , -NHCONR 19 R 20 , -NHCOOR 21 , -SR 22 , -SO2R 23 , -SO2OR 24 , -NHSO2R 25 , -SO2NR 26 R 27 , -(R 28 O) n’ R 29 R represents a heterocyclic group or a hydrocarbon group which may have a substituent, and adjacent substituents may be linked to each other to form a ring. 10 ~R 12 and R 21 ~R 25 R each independently represents a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. 13 ~R 20 , R 26 ~R 27 and R 29 R each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. 28each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms. n' represents an integer of 1 to 18. Each X independently represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. Each Q independently represents a direct bond or a divalent organic group; Z 0 each independently represents a group that can be derived to an organic cationic group or an organic cationic group. Each E independently represents a substituent, and adjacent substituents E may form a ring. Each of m and n independently represents an integer of 0 to 4.

[0012] <3> The above <1> or <2> A colorant dispersion comprising the squarylium colorant according to claim 1, a dispersant, and a solvent. <4> The above <1> or <2> and a binder component. <5> The above <1> or <2> An optical filter comprising the squarylium color material according to claim 1. <6> The above <5> A display device comprising the optical filter according to claim 1. Effect of the Invention

[0013] According to the embodiments of the present disclosure, it is possible to provide a squarylium colorant having excellent heat resistance and light resistance, a colorant dispersion containing the squarylium colorant, an ink composition, an optical filter, and a display device. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic configuration diagram of an example of a display device according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a schematic configuration diagram of another example of a display device according to an embodiment of the present disclosure. [Diagram 3] FIG. 3 is a schematic diagram showing an example of the molecular skeleton of a squarylium dye used in the squarylium color material of the present disclosure. [Figure 4] FIG. 4 is a schematic diagram showing an example of a squarylium color material of the present disclosure. [Diagram 5] FIG. 5 is a schematic diagram illustrating an example of a squarylium color material of the present disclosure that includes a colorless organic cation. [Figure 6] FIG. 6 is a 1H-NMR spectrum of squarylium dye 1. [Figure 7] FIG. 7 is a 1H-NMR spectrum of squarylium dye 2. [Figure 8] FIG. 8 is a 1H-NMR spectrum of squarylium dye 3. [Figure 9] FIG. 9 is a 1H-NMR spectrum of the comparative squarylium dye 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the embodiments and examples of the present disclosure will be described with reference to the drawings. However, the present disclosure can be implemented in many different forms, and is not to be interpreted as being limited to the description of the embodiments and examples exemplified below. In addition, in order to make the explanation clearer, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual form, but these are merely examples and do not limit the interpretation of the present disclosure. In addition, in this specification and each figure, elements similar to those described above with respect to the previous figures may be given the same reference numerals, and detailed explanations may be omitted as appropriate. In addition, for convenience of explanation, the terms "upper" and "lower" may be used in the explanation, but the up-down direction may be reversed. "In this specification, when a certain component or region is described as being "on (or under)" another component or region, unless otherwise specified, this includes not only the case where it is directly on (or directly under) the other component, but also the case where it is above (or below) the other component, i.e., the case where another component is included between the other component and the component above (or below) the other component.

[0016] In the present disclosure, (meth)acrylic refers to either acrylic or methacrylic, and (meth)acrylate refers to either acrylate or methacrylate. In addition, in this specification, the terms "plate," "sheet," and "film" are not distinguished from one another solely based on the difference in name, and a "film surface (plate surface, sheet surface)" refers to a surface that coincides with the planar direction of the target film-like (plate-like, sheet-like) member when viewed overall and globally. In this disclosure, the term "colorant" refers to a compound that absorbs at least a portion of visible light (light with a wavelength of 400 nm to 700 nm) and near-infrared light (light with a wavelength of 700 nm to 1100 nm), and also includes a compound that absorbs only near-infrared light. The term "organic group" refers to a group containing a carbon atom, and the term "organic cation" refers to a group containing a carbon atom in the cationic portion. In the present disclosure, unless otherwise specified, the direction of the bond of the divalent linking group is arbitrary. That is, for example, when the divalent linking group of Q in general formula (2) contains -CONH-, -CO is on the phenylene group side and -NH is on the Z 0 On the other hand, -NH may be on the phenylene group side and -CO may be on the Z 0 It may be on the side. The squarylium colorant, colorant dispersion, ink composition, optical filter, and display device of the present disclosure will be described in detail below.

[0017] I. Squaryllium dye A squarylium colorant according to one embodiment of the present disclosure is a squarylium colorant comprising a squarylium dye represented by the following general formula (1) and a salt-forming compound of a heteropolyacid.

[0018] [ka] (In formula (1), R 1 ~R 8 each independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, -OR 10 , -OCOR 11 , -COOR 12 , -COR 13 , -NR14 R 15 , -NHCOR 16 , -CONR 17 R 18 , -NHCONR 19 R 20 , -NHCOOR 21 , -SR 22 , -SO2R 23 , -SO2OR 24 , -NHSO2R 25 , -SO2NR 26 R 27 , -(R 28 O) n’ R 29 R represents a heterocyclic group or a hydrocarbon group which may have a substituent, and adjacent substituents may be linked to each other to form a ring. 10 ~R 12 and R 21 ~R 25 R each independently represents a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. 13 ~R 20 , R 26 ~R 27 and R 29 R each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. 28 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms. n' represents an integer of 1 to 18. Each X independently represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. Each Y independently represents a divalent organic group; 0 each independently represents a group that can be derived to an organic cationic group or an organic cationic group.

[0019] The squarylium colorant according to one embodiment of the present disclosure is a squarylium colorant having excellent heat resistance and light resistance, which is obtained by converting a squarylium dye represented by the general formula (1) in which an indole skeleton is directly bonded to a squaric acid moiety into a salt-forming compound using a heteropolyacid.

[0020] Conventionally, organic dyes are dissolved in a solvent to form a film, but since they tend to aggregate and precipitate in the film, it is difficult to create a uniform film, and as a result, it is difficult to effectively and uniformly exhibit the function of selectively absorbing light of unwanted emission wavelengths. In addition, conventional organic dyes have poor heat resistance and light resistance, which has been a problem in practical use. When an organic dye forms a salt-forming compound with a heteropolyacid, two or more cationized organic dyes are ionically bonded to one polyvalent heteropolyacid anion. Therefore, in the salt-forming compound of an organic dye and a heteropolyacid, a plurality of organic dyes form one molecule with the heteropolyacid anion at the center, and furthermore, ion pair formation between the molecules is possible, so that the association between the molecules is promoted, resulting in fine particles that are poorly soluble in a solvent. When the colorant is present in the form of fine particles, photodegradation is likely to occur only on the particle surface, and the progress of photodegradation is suppressed, so that it is presumed that the light resistance is improved compared to that of an organic dye. However, conventional squarylium colorants in which a squarylium dye is used as a salt-forming compound with a heteropolyacid still have insufficient heat resistance and light resistance in some cases.

[0021] In contrast, the squarylium colorant of one embodiment of the present disclosure uses a squarylium dye represented by the general formula (1) in which an indole skeleton is directly bonded to a squaric acid moiety as the squarylium dye. In the squarylium dye represented by the general formula (1) in which an indole skeleton is directly bonded to a squaric acid moiety, indole is highly stable against heat and light, so it is considered that the light resistance and heat resistance are high. Since the localization of electrons at the nitrogen moiety contained in the indole ring is suppressed compared to the case of a pyrrole ring or an amine, the reactivity at the nitrogen moiety is low. Therefore, it is considered that oxidation reactions in the presence of light or under high temperature conditions, which lead to deterioration of the dye, do not easily proceed, and the light resistance and heat resistance are high.

[0022] Furthermore, the squarylium dye represented by the general formula (1) in which an indole skeleton is directly bonded to the squaric acid moiety can have a maximum absorption wavelength (λmax) of 550 nm to 630 nm within a wavelength range of 400 nm to 700 nm in the absorption spectrum. In addition, the squarylium dye represented by the above general formula (1) in which an indole skeleton is directly bonded to the squaric acid moiety can suppress the spread of the electron distribution involved in color development, and is likely to give a sharp absorption with a narrow half-width.

[0023] <Squarylium dyes> Squarylium dyes are dyes that have a four-membered ring derived from squaric acid. In the squarylium colorant of the present disclosure, a squarylium dye represented by the following general formula (1) is used.

[0024] [ka] (In formula (1), R 1 ~R 8 each independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, -OR 10 , -OCOR 11 , -COOR 12 , -COR 13 , -NR 14 R 15 , -NHCOR 16 , -CONR 17 R 18 , -NHCONR 19 R 20 , -NHCOOR 21 , -SR 22 , -SO2R 23 , -SO2OR 24 , -NHSO2R 25 , -SO2NR 26 R 27 , -(R 28 O) n’ R 29 R represents a heterocyclic group or a hydrocarbon group which may have a substituent, and adjacent substituents may be linked to each other to form a ring. 10 ~R 12 and R 21 ~R 25 R each independently represents a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. 13 ~R 20 , R 26 ~R27 and R 29 R each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. 28 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms. n' represents an integer of 1 to 18. Each X independently represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. Each Y independently represents a divalent organic group; 0 each independently represents a group that can be derived to an organic cationic group or an organic cationic group.

[0025] R 1 ~R 8 In the above, the hydrocarbon group in the optionally substituted hydrocarbon group includes a saturated hydrocarbon group, an unsaturated hydrocarbon group, or a combination thereof. R 1 ~R 8 In the above, the number of carbon atoms in the hydrocarbon group which may have a substituent may be 1 to 30, 1 to 20, 1 to 15, 1 to 12, 1 to 8, or 1 to 6. The saturated hydrocarbon group may be linear, branched, or cyclic, or may be a combination of these. The unsaturated hydrocarbon group may be linear, branched, or cyclic, or may be a combination of these.

[0026] Examples of saturated hydrocarbon groups include linear alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-octyl, n-decyl, and n-dodecyl groups; branched alkyl groups such as isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, and 2-ethylhexyl groups; alicyclic saturated hydrocarbon groups such as cyclopropyl, cyclopentyl, cyclohexyl, norbornyl, and adamantyl groups; and combinations of these groups such as cyclopentylmethyl and cyclohexylmethyl groups. Examples of the unsaturated hydrocarbon group include aromatic hydrocarbon groups such as a phenyl group, a naphthyl group, and a biphenyl group; unsaturated aliphatic hydrocarbon groups such as a vinyl group, a propenyl group, a butenyl group, a pentenyl group, and an ethynyl group; and monovalent alicyclic unsaturated hydrocarbon groups such as a cyclopropenyl group, a cyclopentenyl group, and a cyclohexenyl group. The hydrocarbon group may be a combination of a saturated hydrocarbon group and an unsaturated hydrocarbon group, or may be an aralkyl group such as a benzyl group or a naphthylmethyl group, or an alkylaryl group such as a methylphenyl group or a dimethylphenyl group.

[0027] In addition, examples of the substituent of the hydrocarbon group include a halogen atom, a nitro group, a cyano group, a hydroxyl group, -OR 10 , -OCOR 11 , -COOR 12 , -COR 13 , -NR 14 R 15 , -NHCOR 16 , -CONR 17 R 18 , -NHCONR 19 R 20 , -NHCOOR 21 , -SR 22 , -SO2R 23 , -SO2OR 24 , -NHSO2R 25 , -SO2NR 26 R 27 , -(R 28 O) n’ R 29 Examples of the substituent of the hydrocarbon group include R 1 ~R 8 Halogen atoms in -OR 10 , -OCOR 11 , -COOR 12 , -COR 13 , -NR 14 R 15 , -NHCOR 16 , -CONR 17 R 18 , -NHCONR 19 R 20 , -NHCOOR 21, -SR 22 , -SO2R 23 , -SO2OR 24 , -NHSO2R 25 , -SO2NR 26 R 27 , -(R 28 O) n’ R 29 , may be the same as a heterocyclic group.

[0028] R 1 ~R 8 In the above, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Also, -OR 10 , -OCOR 11 , -COOR 12 , -COR 13 , -NR 14 R 15 , -NHCOR 16 , -CONR 17 R 18 , -NHCONR 19 R 20 , -NHCOOR 21 , -SR 22 , -SO2R 23 , -SO2OR 24 , -NHSO2R 25 , -SO2NR 26 R 27 , -(R 28 O) n’ R 29 In R 10 ~R 12 and R 21 ~R 25 R each independently represents a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. 13 ~R 20 , R 26 ~R 27 and R 29 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. R 10 ~R 29 The hydrocarbon group having 1 to 6 carbon atoms which may have a substituent in R 1 ~R 8Among the optionally substituted hydrocarbon groups in the above, the hydrocarbon groups may be the same as the optionally substituted hydrocarbon groups having 1 to 6 carbon atoms, may be hydrocarbon groups having 1 to 3 carbon atoms, or may be unsubstituted. R 28 Each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms. The divalent hydrocarbon group may be either saturated or unsaturated, and may be any of linear, branched, cyclic, and combinations of cyclic and linear or branched. From the viewpoint of improving the solvent solubility, R 28 The divalent hydrocarbon group of R is preferably a linear or branched hydrocarbon group. 28 The carbon number of the divalent hydrocarbon group may be 2 to 8, or 2 to 6, or preferably 2 to 3, and may be an ethylene group or a propylene group. Furthermore, n' is 1 to 18, or may be 1 to 12, or may be 1 to 6.

[0029] R 1 ~R 8 In the above, the heterocyclic group is preferably a monocyclic ring or a condensed ring, and may be a monocyclic ring or a condensed ring having 2 to 8 condensed rings, or may be a monocyclic ring or a condensed ring having 2 to 4 condensed rings. The number of heteroatoms constituting the ring of the heterocyclic group is preferably 1 to 3. The heteroatom constituting the ring of the heterocyclic group may be at least one selected from the group consisting of a nitrogen atom, an oxygen atom, a sulfur atom, and a phosphorus atom. The heterocyclic group is preferably a 5-membered ring or a 6-membered ring. The number of carbon atoms constituting the ring of the heterocyclic group may be 3 to 30, 3 to 18, 3 to 12, or 3 to 5. Specific examples of heterocyclic groups include pyrrole, furan, phosphole, imidazole, oxazole, thiazole, pyridine, pyran, and phospholine.

[0030] Also, R 1 ~R 8may be bonded to adjacent substituents to form a ring. That is, adjacent substituents may be bonded to each other to form a condensed ring with the benzene ring to which the substituent is bonded. The ring formed may be a heterocycle containing at least one heteroatom. Examples of the condensed ring with the benzene ring when a ring is formed by adjacent substituents include a naphthalene ring, a benzofuran ring, a benzothiophene ring, a quinoline ring, an indole ring, an anthracene ring, an acridine ring, and a phenanthrene ring.

[0031] Each X independently represents a hydrogen atom or an optionally substituted hydrocarbon group having 1 to 12 carbon atoms. The hydrocarbon group having 1 to 12 carbon atoms for X includes a saturated hydrocarbon group, an unsaturated hydrocarbon group, or a combination thereof having 1 to 12 carbon atoms. The hydrocarbon group having 1 to 12 carbon atoms which may have a substituent in X is the same as R 1 ~R 8 Among the optionally substituted hydrocarbon groups in the above, the optionally substituted hydrocarbon groups having 1 to 12 carbon atoms may be the same as those in the above.

[0032] Of these, X is preferably a hydrogen atom or a hydrocarbon group having 3 to 12 carbon atoms which may have a substituent, from the viewpoint of improving heat resistance and light resistance. Among them, when X is a bulky group, it is preferable because the effect of reducing side absorption is improved when a salt-forming compound is prepared from the squarylium dye represented by the general formula (1) and a heteropolyacid. From the viewpoint of reducing side absorption, X is preferably a hydrocarbon group having 4 to 12 carbon atoms which may have a substituent, X is preferably a hydrocarbon group having 6 to 12 carbon atoms which may have a substituent, and X is preferably a hydrocarbon group having a ring structure such as an alicyclic saturated hydrocarbon group, an alicyclic unsaturated hydrocarbon group, or an aromatic hydrocarbon group, or a branched hydrocarbon group. It is presumed that when X is a bulky group, it is possible to physically separate the chromophores of the dye from each other, thereby suppressing interaction. When the side absorption of the squarylium colorant is reduced, the film containing the squarylium colorant is able to suppress the absorption of light in the required wavelength region and selectively absorb light in the unnecessary wavelength region, and can selectively and effectively reduce only the light in the unnecessary wavelength region. Furthermore, the squarylium colorant of the present disclosure with reduced side absorption is a colorant with improved wavelength selectivity. When the squarylium colorant of the present disclosure is used, the decrease in color purity and brightness caused by the side absorption is suppressed, and color purity and brightness are improved.

[0033] In the general formula (1), each Y independently represents a divalent organic group, and at least one of the indole rings of the squarylium dye moiety and Z which is a group that can be derived to a cationic group or an organic cationic group are 0 It functions as a linking group to the Examples of the divalent organic group in Y include -CONH-, -COO-, -CO-, a divalent hydrocarbon group which may contain a heteroatom, or a combination thereof. Examples of the divalent hydrocarbon group which may contain a heteroatom include a divalent hydrocarbon group which may contain O, S, or N in the carbon chain. Examples of the divalent organic group in Y include -CONH-, -COO-, -CO-, a divalent hydrocarbon group, a divalent heterocyclic group, and a divalent group formed by combining a divalent hydrocarbon group with -CONH-, -COO-, -CO-, -O-, -S-, or the like. The divalent hydrocarbon group may be either saturated or unsaturated, and may be any of linear, branched, cyclic, or a combination of cyclic and linear or branched. The divalent hydrocarbon group has preferably 1 to 30 carbon atoms, more preferably 1 to 20, and further preferably 1 to 15. The divalent hydrocarbon group may have 1 to 12 carbon atoms or may have 2 to 8 carbon atoms. The divalent heterocyclic group may be a 5-membered or 6-membered ring, which may be a monocyclic or condensed ring. Examples of heteroatoms contained in the heterocyclic group include a nitrogen atom, an oxygen atom, and a sulfur atom, and nitrogen and sulfur atoms are preferred. The number of heteroatoms is preferably 1 to 3, and more preferably 1 to 2. Specific examples include aromatic heterocyclic groups derived from monocyclic or polycyclic aromatic rings, such as a 5-membered or 6-membered ring containing at least one of a nitrogen atom, an oxygen atom, and a sulfur atom. Examples of heterocyclic groups include a pyrrole ring, a furan ring, a thiophene ring, a pyridine ring, an indole ring, a benzofuran ring, and a benzothiophene ring.

[0034] From the standpoint of stability against light, the divalent organic group for Y is preferably a divalent hydrocarbon group or a combination of a divalent hydrocarbon group and -CONH-. If the squarylium dye moiety involved in color development and the cationic group are electronically independent, the spread of the electron distribution involved in color development can be suppressed and sharp absorption with a narrow half-width can be obtained. In particular, Y may be a combination of an aromatic ring and a hydrocarbon group in which the carbon atom directly bonded to the aromatic ring does not have a π-bond, a combination of an aromatic ring and an aliphatic hydrocarbon group having a saturated aliphatic hydrocarbon group at the end directly bonded to the aromatic ring, or a combination of an aromatic ring and an amide bond. Indole ring and Z 0 From the viewpoint of being inert to oxidation, reduction, or hydrolysis reactions that may cause dye deterioration and linking in a chemically stable manner, suitable examples of Y include, but are not limited to, the following chemical formulas (y-1) to (y-16) and branched alkylene groups having 3 to 6 carbon atoms. In (y-1), (y-7) and (y-14), n is 1 to 6, and may be 2 to 6. The chemical formulas (y-1) to (y-16) and the branched alkylene groups having 3 to 6 carbon atoms may further have a substituent. The substituent here may be the same as the substituent of the hydrocarbon group. Among these, in terms of providing sharp absorption with a narrow half-width, it is preferable that Y is (y-1), (y-3), (y-5), (y-6), (y-7), (y-8), (y-9), (y-10), (y-11), (y-12) or (y-16), or contains a linear or branched alkylene group having 3 to 6 carbon atoms.

[0035] [ka] In the chemical formulas (y-1), (y-7) and (y-14), n is 1 to 6. In the formulas, * represents an indole ring or Z 0 The bond position is shown.)

[0036] In general formula (1), Z 0 is an organic cationic group (Z + ) or an organic cationic group. Z 0 Among them, the organic cationic group (Z + Examples of groups that can be derived to the organic cation group (Z) include monovalent nitrogen-containing compound groups, sulfur-containing compound groups, and phosphorus-containing compound groups that can become oniums. + ) is not limited to a protonated onium, but may be an onium substituted with a hydrocarbon group instead of a proton. Examples of nitrogen-containing compounds that can become oniums include primary amines, secondary amines, tertiary amines, heterocyclic amines such as piperidine, pyrrolidine, and morpholine, nitrogen-containing aromatic compounds such as pyridine, imidazole, and pyrazole, imidazoline, guanidine and its derivatives, and amidine and its derivatives. Examples of guanidine or amidine derivatives include structures in which a hydrocarbon group such as an alkyl group is substituted for the nitrogen. Examples of sulfur-containing compounds that can become oniums include thiols and thioethers. Examples of phosphorus-containing compounds that can become oniums include phosphines. Z 0 Among them, the organic cationic group (Z + ) is a group (Z0 ) is an onium, and examples thereof include ammonium cations such as tetraalkylammonium cation, trialkylammonium cation, dialkylammonium cation, and monoalkylammonium cation; piperidinium cation, pyrrolidinium cation, morpholinium cation, pyridinium cation, and imidazolium cation. Examples of the cationic group that can be used include sulfonium cations such as trialkylsulfonium cations, and phosphonium cations such as tetraalkylphosphonium cations. Among these, Z is the most popular because it can be easily cationized by proton addition and the raw materials are relatively inexpensive and readily available. 0 As the alkyl group, a tertiary amino group, a pyridyl group, an imidazolyl group, a pyrazolyl group, a guanidyl group, etc. are preferably used. Since the onium formed is stable as a cation, the preferred Z 0 Examples of the compound include, but are not limited to, the following chemical formulas (z-1) to (z-18).

[0037] [ka] (In chemical formulas (z-2) to (z-5) and (z-18), R and R' each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or -(CH2CH2O) n” -R ” n" is 2 to 12; R ” represents a hydrocarbon group having 1 to 4 carbon atoms. In the formula, * indicates the bonding position with Y.

[0038] -(CH2CH2O) in chemical formulas (z-2) to (z-5) and (z-18) n” -R ” In the formula, n″ is preferably 1 to 8, and more preferably 1 to 6. ” may be a methyl group, an ethyl group, an n-propyl group, an i-propyl group, or an n-butyl group.

[0039] The symmetry of the electronic state involved in the color development of squarylium dyes is increased, and the dyes tend to give sharp absorption with a narrow half-width. Therefore, it is preferable to use multiple Y and multiple Z 0 are preferably the same as each other.

[0040] The squarylium dye used in the present invention may be a squarylium dye represented by the following general formula (2), from the viewpoint of suppressing side absorption of the coloring material.

[0041] [ka] (In formula (2), R 1 ~R 8 each independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, -OR 10 , -OCOR 11 , -COOR 12 , -COR 13 , -NR 14 R 15 , -NHCOR 16 , -CONR 17 R 18 , -NHCONR 19 R 20 , -NHCOOR 21 , -SR 22 , -SO2R 23 , -SO2OR 24 , -NHSO2R 25 , -SO2NR 26 R 27 , -(R 28 O) n’ R 29 R represents a heterocyclic group or a hydrocarbon group which may have a substituent, and adjacent substituents may be linked to each other to form a ring. 10 ~R 12 and R 21 ~R 25 R each independently represents a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. 13 ~R 20 , R 26 ~R 27 and R 29R each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. 28 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms. n' represents an integer of 1 to 18. Each X independently represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. Each Q independently represents a direct bond or a divalent organic group; Z 0 each independently represents a group that can be derived to an organic cationic group or an organic cationic group. Each E independently represents a substituent, and adjacent substituents E may form a ring. Each of m and n independently represents an integer of 0 to 4.

[0042] The squarylium dye represented by the general formula (2) is -QZ 0 Since is substituted at the ortho position relative to the bonding position of the indole ring, -QZ 0 The torsion angle of the benzene ring to which -QZ is bonded tends to become large. 0 Therefore, the squarylium dye represented by the general formula (2) has one -QZ with respect to the bisindolesquarylium plane. 0 is located diagonally above, and the other -QZ 0 is located diagonally below, resulting in an S-shaped skeleton as shown in Fig. 3. Therefore, as shown in Fig. 4, when a salt is formed between a squarylium dye cation 101 represented by the general formula (2) and a heteropolyacid 103, it is presumed that the bisindole squarylium planes are less likely to approach each other, which makes it easier to suppress interactions between the dyes, and in particular makes it easier to reduce side absorption.

[0043] In the squarylium dye represented by the general formula (2), R 1 ~R 8 , X, and Z 0 is R described in the squarylium dye represented by the general formula (1) above. 1 ~R 8, X, and Z 0 It may be similar to:

[0044] Each E independently represents a substituent. Examples of the substituent include a halogen atom, a nitro group, a cyano group, a hydroxyl group, -OR 10 , -OCOR 11 , -COOR 12 , -COR 13 , -NR 14 R 15 , -NHCOR 16 , -CONR 17 R 18 , -NHCONR 19 R 20 , -NHCOOR 21 , -SR 22 , -SO2R 23 , -SO2OR 24 , -NHSO2R 25 , -SO2NR 26 R 27 , -(R 28 O) n’ R 29 , a heterocyclic group, or a hydrocarbon group which may have a substituent, and in the squarylium dye represented by the general formula (1), R 1 ~R 8 It may be similar to that described above.

[0045] In addition, adjacent substituents E may form a ring. That is, adjacent substituents E may be bonded to each other to form a condensed ring with the benzene ring to which the substituent E is bonded. The ring formed may be a heterocycle containing at least one heteroatom. In the case where adjacent substituents E form a ring, examples of the condensed ring with the benzene ring include a naphthalene ring, a benzofuran ring, a benzothiophene ring, a quinoline ring, an indole ring, an anthracene ring, an acridine ring, and a phenanthrene ring. m and n each independently represent an integer of 0 to 4, may be an integer of 0 to 2, or may be 0 or 1.

[0046] In the squarylium dye represented by the general formula (2), Q represents a direct bond or a divalent organic group, and Z represents a phenylene group bonded to an indole ring of the squarylium dye moiety, and a group that can be derived to a cationic group or an organic cationic group. 0 In this context, a direct bond means a covalent bond without any intervening atom or group. Examples of the divalent organic group in Q include -CONH-, -COO-, -CO-, a divalent hydrocarbon group which may contain a heteroatom, or a combination thereof. The divalent hydrocarbon group which may contain a heteroatom in Q may be the same as the divalent hydrocarbon group which may contain a heteroatom in Y. The divalent hydrocarbon group may be either saturated or unsaturated, and may be any of linear, branched, cyclic, or a combination of cyclic and linear or branched. The divalent hydrocarbon group has preferably 1 to 30 carbon atoms, more preferably 1 to 20, and further preferably 1 to 15. The divalent hydrocarbon group may have 1 to 12 carbon atoms or may have 2 to 8 carbon atoms. From the standpoint of stability against light, the divalent organic group in Q is preferably a divalent hydrocarbon group, -CONH-, or a combination of a divalent hydrocarbon group and -CONH-.

[0047] Suitable examples of Q from the viewpoint of suppressing the spread of electron distribution related to color development and imparting sharp absorption with a narrow half-width include, but are not limited to, the following chemical formulas (q-1) to (q-12), a branched alkylene group having 3 to 6 carbon atoms, and a combination of at least two of these. In (q-1) and (q-12), n can be 1 to 6, and may be 2 to 6. The divalent groups of the chemical formulas (q-1) to (q-12), the branched alkylene group having 3 to 6 carbon atoms, and a combination of at least two of these may further have a substituent. The substituent here may be the same as the substituent of the hydrocarbon group. Among these, in terms of providing sharp absorption with a narrow half-width, it is preferable that Q contains (q-1), (q-3), (q-5), (q-6), (q-7), (q-8), (q-9), (q-10), or a linear or branched alkylene group having 3 to 6 carbon atoms. In addition, from the viewpoint of being able to suppress the spread of electron distribution involved in color development and imparting sharp absorption with a narrow half-width, it is preferable that the atom of Q directly bonded to the phenylene group is a carbon atom not having a π bond or a nitrogen atom, and Q may be an aliphatic hydrocarbon group having a saturated aliphatic hydrocarbon group at the end directly bonded to the phenylene group, or an aromatic hydrocarbon group having a saturated aliphatic hydrocarbon group at the end directly bonded to the phenylene group, a hydrocarbon group having -CO- at the end directly bonded to the phenylene group, or a hydrocarbon group having -NH- at the end directly bonded to the phenylene group.

[0048] [ka] In the chemical formulas (q-1) and (q-12), n is 1 to 6. In the formulas, * represents a phenylene ring or Z 0 The bond position is shown.)

[0049] -QZ used in the present invention 0 Examples of combinations include, but are not limited to, the following:

[0050] [Table 1]

[0051] [Table 2]

[0052] In the squarylium dye used in the present invention, the cation is delocalized as shown below. 1 and A 2 each independently represents a substructure bound to the squaric acid moiety.

[0053] [ka]

[0054] The squarylium dye used in the present invention can be produced by referring to the known production methods described in the above-mentioned publications or known production methods described in other documents. The method for producing the compound represented by the general formula (1) is not particularly limited. For example, a method for producing the compound represented by the general formula (1) can be used to combine X, Y and Z by a carbon-carbon forming reaction such as a reaction using a Grignard reagent, a coupling reaction using a palladium catalyst, an Ullmann reaction, a Friedel-Crafts reaction, an aldol reaction, or a Wittig reaction. 0 An example of such a method is reacting an indole or the like into which the following has been introduced with squaric acid in the presence of a base.

[0055] <Heteropolyacid> The heteropolyacid used in the present invention is a polyacid having two or more kinds of central atoms of the constituent oxoacids. The heteropolyacid becomes a heteropolyacid anion in the salt forming compound. The heteropolyacid anion is represented by the formula (L l M m O n ) a- (a is a number of 2 or more). In the ionic formula, L is a heteroatom, M is a polyatom, O is an oxygen atom, and l, m, and n are the composition ratios of the respective atoms. Examples of the polyatom M include Mo (molybdenum), W (tungsten), V (vanadium), Ti (titanium), and Nb (niobium), and the polyatom M may contain two or more kinds of transition metal atoms. The heteroatom L is not particularly limited, but examples thereof include Si, P, As, S, Fe, and Co. + Or H + A counter cation such as

[0056] Among these, polyacids having one or more elements selected from tungsten (W) and molybdenum (Mo) are preferred because of their excellent heat resistance. Examples of such heteropolyacids include phosphotungstate ions [PW 12 O 40 ] 3- , [P2W 18 O 62 ] 6- , silicotungstate ion [SiW 12 O 40 ] 4- , phosphomolybdate ion [PMo 12 O 40 ] 3- , silicomolybdate ion [SiMo 12 O 40 ] 4- , phosphotungstomolybdate ion [PW 12-s Mo s O 40 ] 3- (s is an integer between 1 and 11), [P2W 18-t Mo t O 62 ] 6- (t is an integer between 1 and 17), and the silicotungstomolybdate ion [SiW 12-u Mo u O 40 ] 4- (u is an integer between 1 and 11).

[0057] From the viewpoint of improving light fastness, the heteropolyacid is preferably a heteropolyacid having an oxidation-reduction potential greater than −0.3 V versus a silver / silver chloride electrode. By using such a heteropolyacid anion having an oxidation-reduction potential greater than a specific value as the counter anion, the heteropolyacid, which is particularly susceptible to reduction, absorbs the energy generated when an organic dye excited by light returns to the ground state, thereby suppressing the generation of singlet oxygen upon light irradiation, and thus further improving the light fastness of the colorant.

[0058] The heteropolyacid used in the present disclosure, which has an oxidation-reduction potential of greater than -0.3 V versus a silver / silver chloride electrode, is, for example, HSiMo 12 O 40 (-0.232V), H3PW6Mo6O 40(-0.197V), H3PW3Mo9O 40 (-0.153V), H3PMo 12 O 40 (-0.082V), H6PW9V3O 40 (0.045V), H5PW 10 V2O 40 (0.050V), H6PMo9V3O 40 (0.168V), H3AsMo 12 O 40 (0.183V), H4PW 11 V1O 40 (0.224V), H5PMo 10 V2O 40 (0.233V), H4PMo 11 V1O 40 (0.261V) etc. Here, the redox potential specified in the present disclosure refers to a measured value of an aqueous heteropolyacid solution using a silver / silver chloride standard electrode (KCl saturated aqueous solution) with platinum as the working electrode, and the aqueous heteropolyacid solution may be an aqueous solution in which 1 mM heteropolyacid is dissolved in a 0.5 M aqueous sodium sulfate electrolyte solution. As for the redox potential of the heteropolyacid under the above measurement conditions, the redox potential (V) values ​​in FIG. 9 of Journal of Molecular Catalysis A: Chemistry 212 (2004) 229-236 can also be referred to, and the value in parentheses above is the value in the said literature.

[0059] <Colorless organic cation> The squarylium color material of the present invention may further contain a colorless organic cation in order to improve light fastness and reduce side absorption. Fig. 5 is a schematic diagram showing an example of a squarylium colorant of the present disclosure further containing a colorless organic cation. Fig. 5 shows, as an example, a salt-forming compound (squarylium colorant of the present disclosure) 110 in which a squarylium dye cation 101 represented by the general formula (1), a divalent colorless organic cation 102, and a trivalent heteropolyacid anion 103 form a salt by ionic bonding. In this way, in the salt-forming compound 110 of the squarylium colorant of the present disclosure further containing a colorless organic cation, it is possible to increase the distance between the squarylium dye cations 101 without affecting the absorption wavelength by the colorless organic cation 102, and it is presumed that the interaction between the squarylium dyes is suppressed, making it difficult for side absorption to occur. It is also presumed that the amount of heteropolyacid that contributes to improving lightfastness increases relative to the amount of squarylium dye in the squarylium colorant, which is the salt-forming compound 110, and thus the lightfastness is further improved.

[0060] The colorless organic cation used in the squarylium colorant of the present invention may be an organic cation having an absorption maximum in the wavelength region of 400 nm or less. Furthermore, the colorless organic cation may be a compound that has no absorption in the wavelength region of more than 400 nm and not more than 780 nm. The colorless organic cation used in the present invention is derived from a nitrogen-containing compound, a sulfur-containing compound, or a phosphorus-containing compound that can be an onium. The organic cation is not limited to a protonated onium, and may be an onium substituted with a hydrocarbon group instead of a proton. Examples of nitrogen-containing compounds that can become oniums include tertiary amines, piperidine, pyrrolidine, pyridine, imidazoline, and morpholine. Examples of sulfur-containing compounds that can become oniums include thiols and thioethers. Examples of phosphorus-containing compounds that can become oniums include phosphines.

[0061] Examples of the colorless organic cation used in the present invention include structures in which a nitrogen-containing compound, a sulfur-containing compound, or a phosphorus-containing compound that can become an onium has become an onium, and examples of such compounds include compounds containing at least one type of cationic group selected from the group consisting of an ammonium group, a pyridinium group, a piperidinium group, a pyrrolidinium group, a pyridinium group, an imidazolium group, a morpholinium group, a sulfonium group such as a trialkylsulfonium cationic group, and a phosphonium group such as a triarylalkylphosphonium group or a tetraalkylphosphonium group.

[0062] The colorless organic cation used in the present invention is preferably a divalent or higher cation, and preferably contains two or more cationic groups in one molecule. The upper limit of the valence of the colorless organic cation used in the present invention is not particularly limited, but may be tetravalent or less, or may be trivalent or less.

[0063] The colorless organic cation used in the present invention is preferably a phosphonium compound, more preferably a divalent or higher phosphonium compound, because it has no absorption in the visible region.

[0064] The colorless organic cation used in the present invention is preferably a phosphonium compound represented by the following general formula (A) from the viewpoint of molecular bulkiness for suppressing association or interaction between dye cations when a dye cation, a heteropolyacid, and a colorless organic cation form a salt. Formula (A): A―[P + R A 3] a (In formula (A), A is an a-valent organic group, and R A each independently represents a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent, and a is an integer of 2 to 4.

[0065] In formula (A), R Aeach independently represents a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent, and examples of the hydrocarbon group having 1 to 6 carbon atoms include saturated or unsaturated hydrocarbon groups having 1 to 6 carbon atoms. Examples of the saturated hydrocarbon group having 1 to 6 carbon atoms include linear alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group; branched alkyl groups such as an isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an isopentyl group, and a neopentyl group; and alicyclic saturated hydrocarbon groups such as a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the unsaturated hydrocarbon group having 1 to 6 carbon atoms include an aromatic hydrocarbon group such as a phenyl group; an unsaturated aliphatic hydrocarbon group such as a vinyl group, a propenyl group, a butenyl group, or a pentenyl group; and an alicyclic unsaturated hydrocarbon group such as a cyclopropenyl group, a cyclopentenyl group, or a cyclohexenyl group. In addition, examples of the substituent of the hydrocarbon group include a halogen atom, a nitro group, a cyano group, a hydroxyl group, -OR a1 , -OCOR a2 , -COOR a3 , -CONHR a4 , -NHCOR a5 , or -NR a6 R a7 (where R a1 , R a2 , and R a3 each independently represents a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent; R a4 , R a5 , R a6 and R a7 R each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. a1 , R a2 , R a3 , R a4 , R a5 , R a6 and R a7 The optionally substituted hydrocarbon group having 1 to 6 carbon atoms in the formula (I) may be the same as above, may be a hydrocarbon group having 1 to 3 carbon atoms, and may not have a substituent.

[0066] In formula (A), A is an a-valent organic group, which may be an aliphatic hydrocarbon group, an aromatic ring group, or a combination thereof, and which may contain a heteroatom such as O (oxygen atom), S (sulfur atom), or N (nitrogen atom) in the carbon chain. In A, the aliphatic hydrocarbon group may be linear, branched or cyclic, the carbon atom may have an unsaturated bond, may have a substituent, and may contain O, S or N in the carbon chain, for example, an ether group, a carbonyl group, an oxycarbonyl group, an amide group, etc. The aromatic ring group in A may be the same as described above, and among others, a monocyclic or polycyclic aromatic group having an aliphatic hydrocarbon group having a saturated aliphatic hydrocarbon group at the end directly bonded to P may be mentioned. The aromatic ring group in A may have a substituent, and may be a heterocycle containing O, S or N. Examples of the substituent that A may have include the above-mentioned R A may be the same as the substituents in Among these, A is preferably an a-valent aliphatic hydrocarbon group, which may be linear, branched or cyclic, and the carbon atom may have an unsaturated bond.

[0067] <Method of manufacturing squarylium color material> The squarylium colorant (salt-forming compound) of the present disclosure can be obtained, for example, by mixing a squarylium dye having a desired structure, a heteropolyacid, and, if necessary, a colorless organic cation in a solvent, and heating as necessary. The squarylium dye, the heteropolyacid, and the colorless organic cation used if necessary may each be used alone or in combination of two or more kinds.

[0068] When the squarylium colorant (salt-forming compound) of the present disclosure further contains a colorless organic cation, the content ratio of the squarylium dye serving as the cation to the colorless organic cation is not particularly limited as long as it can be adjusted to the desired color, and depending on the valence of the cation, from the viewpoint of suppressing the generation of side absorption by maintaining the distance between the dye molecules, the molar ratio of the squarylium dye to the colorless organic cation (squarylium dye:colorless organic cation) may be 6:4 to 2:8, or 5:5 to 3:7.

[0069] Furthermore, when the squarylium colorant (salt-forming compound) of the present disclosure is a normal salt, it is preferable to adjust the number of cations in the squarylium dye and the colorless organic cation, and the number of anions in the heteropolyacid so that the squarylium colorant is a normal salt, since the squarylium colorant has higher dispersibility and dispersion stability than an acid salt or the like.

[0070] <Characteristics of squarylium color material> From the viewpoint of improving color purity in the visible range of a display device, the squarylium colorant may have a maximum absorption wavelength (λmax) within a wavelength range of 400 nm to 700 nm in an absorption spectrum, i.e., a minimum transmission wavelength within a wavelength range of 400 nm to 700 nm in a transmission spectrum of 550 nm to 630 nm or 560 nm to 620 nm; The maximum absorption wavelength to the minimum transmission wavelength within the wavelength range of 400 nm to 700 nm of the squarylium colorant can be appropriately changed by changing the substituent of the squarylium dye. Moreover, the half-value width from the maximum absorption wavelength to the minimum transmission wavelength within the wavelength range of 400 nm to 700 nm may be 85 nm or less, or may be 70 nm or less, in order to cut out only unnecessary light from the display device.

[0071] II. Colorant dispersion liquid A colorant dispersion according to one embodiment of the present disclosure is characterized by containing the squarylium colorant of the present disclosure, a dispersant, and a solvent. The colorant dispersion of the present disclosure contains the squarylium colorant of the present disclosure, which has excellent heat resistance and light resistance, and thus makes it possible to form a film or molded article that has excellent heat resistance and light resistance and is capable of absorbing and reducing light in unnecessary wavelength regions.

[0072] The colorant dispersion of the present disclosure contains at least the squarylium colorant of the present disclosure, a dispersant, and a solvent, and may contain other components as necessary. Hereinafter, each component of the colorant dispersion liquid of the present disclosure will be described in detail in order.

[0073] <Coloring material> The squarylium colorant of the present disclosure used in the colorant dispersion of the present disclosure may be the same as that described above, and therefore a description thereof will be omitted here. In the colorant dispersion of the present disclosure, the squarylium colorant of the present disclosure may be used alone or in combination of two or more. Other coloring materials may also be included. The other coloring materials are blended as necessary for the purpose of controlling color tone. The other coloring materials may be selected from conventionally known materials such as pigments and dyes according to the purpose, and may be used alone or in combination of two or more. The blending amount of the other coloring materials is not particularly limited as long as the effect of the present disclosure is not impaired, and may be the same as that used in the composition described below. In the colorant dispersion liquid of the present disclosure, the content of the colorant is not particularly limited. From the viewpoint of dispersibility and dispersion stability, the content of the colorant is preferably within a range of 5 to 40% by mass, more preferably 10 to 20% by mass, based on the total amount of the colorant dispersion liquid.

[0074] <Dispersant> In the colorant dispersion liquid according to the present disclosure, the colorant is dispersed in a solvent before use. In the present disclosure, a dispersant is used to disperse the colorant well. The dispersant can be appropriately selected from those conventionally used as pigment dispersants. As the dispersant, for example, a cationic, anionic, nonionic, amphoteric, silicone, or fluorine-based surfactant can be used. Among the surfactants, a polymer surfactant (polymer dispersant) is preferred because it can be uniformly and finely dispersed.

[0075] Examples of polymer dispersants include (co)polymers of unsaturated carboxylic acid esters such as polyacrylic acid esters; (co)polymers of unsaturated carboxylic acids such as polyacrylic acid; (partial) amine salts, (partial) ammonium salts, and (partial) alkylamine salts of (co)polymers of unsaturated carboxylic acids such as polyacrylic acid; (co)polymers of hydroxyl-containing unsaturated carboxylic acid esters such as hydroxyl-containing polyacrylic acid esters and modified products thereof; polyurethanes; unsaturated polyamides; polysiloxanes; long-chain polyaminoamide phosphate salts; polyethyleneimine derivatives (amides obtained by reacting poly(lower alkyleneimine) with polyesters containing free carboxyl groups, or bases thereof); polyallylamine derivatives (reaction products obtained by reacting polyallylamine with one or more compounds selected from the three compounds of polyesters having free carboxyl groups, polyamides, or co-condensates of esters and amides (polyesteramides)).

[0076] As the polymer dispersant, an acidic dispersant is preferable because it can suitably disperse the coloring material, which is the salt-forming compound, and has good dispersion stability. Here, an acidic dispersant refers to a dispersant in which the amount of acidic groups is greater than the amount of basic groups, and a basic dispersant refers to a dispersant in which the amount of basic groups is greater than the amount of acidic groups. As the acidic dispersant used in the present disclosure, a resin in which the amount of acidic groups is 80 mol % or more when the total amount of the acidic groups and the basic groups is taken as 100 mol %, is preferable, and a resin that substantially has acidic groups and has no basic groups is more preferable. Among them, the acidic dispersant used in the present disclosure preferably has an acid value but does not have an amine value from the viewpoint of dispersion stability of the colorant. It is presumed that the use of an acidic dispersant not only satisfactorily disperses the color material, which is the salt-forming compound, but also has the effect of allowing the color material, which is the salt-forming compound, to exist stably in the form of an ion pair.

[0077] The acid value of the acidic dispersant used in the present disclosure is preferably 30 mgKOH / g or more, more preferably 60 mgKOH / g or more, and even more preferably 90 mgKOH / g or more. Additionally, the amine value of the acidic dispersant used in the present disclosure is preferably 0 mg KOH / g. The acid value refers to the mass (mg) of potassium hydroxide required to neutralize the acidic components contained in 1 g of the solid content of the dispersant, and is a value measured by the method described in JIS K0070:1992. The amine value represents the mass (mg) of potassium hydroxide equivalent to the amount of hydrochloric acid required to neutralize 1 g of solid content of the dispersant, and is a value measured by the method described in JIS K7237:1995.

[0078] The acidic group of the acidic dispersant used in the present disclosure includes a carboxy group, a phosphoric acid group and its salts, a sulfonic acid group and its salts, and the like. Examples of the acidic dispersant include block or graft copolymers having an acidic group, salts of block copolymers having an acidic group with organic cations such as alkylammonium salts, hydroxyl group-containing carboxylates, fatty acid salts such as salts of high molecular weight polycarboxylates, polyether ester-type anionic surfactants, naphthalenesulfonic acid-formalin condensate salts, phosphates and salts thereof such as polyoxyethylene alkyl phosphates, alkyl sulfate salts, sulfonates such as polyoxyethylene alkyl ether sulfate salts and alkylbenzene sulfonates, and the like.

[0079] Commercially available acidic dispersants include, for example, DISPERBYKR-103, DISPERBYKR-110, DISPERBYK-118, AJISPER PN411, and AJISPER PA111.

[0080] Among the acidic dispersants, from the viewpoint of dispersibility and dispersion stability of the colorant, it is more preferable that the dispersant is a polymer having one or more types selected from the structural unit represented by the following general formula (I) and the structural unit represented by the following general formula (I').

[0081] [ka] (In general formula (I) and general formula (I'), L 1 is a direct bond or a divalent linking group, R 31 is a hydrogen atom or a methyl group, R 32 is a hydroxyl group, a hydrocarbon group, -[CH(R 33 )-CH(R 34 )-O] x1 -R 35 , -[(CH2) y1 -O] z1 -R 35 -OR 36 R is a monovalent group represented by the formula 36 is a hydrocarbon group, -[CH(R 33 )-CH(R 34 )-O] x1 -R 35 , -[(CH2) y1 -O] z1 -R 35 , -C(R 37 )(R 38 )-C(R 39 )(R 40 )-OH or -CH2-C(R 41 )(R 42 )-CH2-OH is a monovalent group. R 33 and R 34 are each independently a hydrogen atom or a methyl group, R 35is a hydrogen atom, a hydrocarbon group, -CHO, -CH2CHO, -CO-CH=CH2, -CO-C(CH3)=CH2 or -CH2COOR 43 R is a monovalent group represented by the formula 43 R is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. 37 , R 38 , R 39 , R 40 , R 41 and R 42 are each independently a hydrogen atom, a hydrocarbon group, or a hydrocarbon group having one or more bonds selected from an ether bond and an ester bond, and R 37 and R 39 may be bonded to each other to form a ring structure. When the ring structure is formed, the ring structure may further include a substituent R 44 R 44 is a hydrocarbon group or a hydrocarbon group having one or more bonds selected from an ether bond and an ester bond. The hydrocarbon group may have a substituent. In the general formula (I'), X + represents an organic cation. x1 represents an integer of 1 to 18, y1 represents an integer of 1 to 5, and z1 represents an integer of 1 to 18.

[0082] In the general formula (I) and the general formula (I'), L 1 is a direct bond or a divalent linking group. 1 A direct bond means that the phosphorus atom is directly bonded to a carbon atom in the main chain skeleton without a linking group. L 1 There are no particular limitations on the divalent linking group in L, so long as it can link a carbon atom in the main chain skeleton to a phosphorus atom. 1Examples of the divalent linking group in include linear, branched or cyclic alkylene groups, linear, branched or cyclic alkylene groups having a hydroxyl group, arylene groups, -CONH- groups, -COO- groups, -NHCOO- groups, ether groups (-O- groups), thioether groups (-S- groups), and combinations thereof. In the present invention, the direction of the bond of the divalent linking group is arbitrary. That is, when the divalent linking group contains -CONH-, -CO may be on the carbon atom side of the main chain and -NH may be on the phosphorus atom side of the side chain, or conversely, -NH may be on the carbon atom side of the main chain and -CO may be on the phosphorus atom side of the side chain.

[0083] The polymer having one or more types selected from the structural unit represented by the general formula (I) and the structural unit represented by the general formula (I') may be similar to the polymer having one or more types selected from the structural unit represented by the general formula (I) and the structural unit represented by the general formula (I') described in JP 2017-002191 A. For the explanation of each symbol of the polymer having one or more selected from the structural units represented by the general formula (I) and the structural units represented by the general formula (I'), please refer to the explanation of each corresponding symbol of the structural units represented by the general formula (I) and the polymer having one or more selected from the structural units represented by the general formula (I') described in JP 2017-002191 A, and the contents of this specification are incorporated herein.

[0084] Among the polymers having one or more types selected from the structural unit represented by the general formula (I) and the structural unit represented by the general formula (I'), the (B) dispersant is preferably a reaction product of a polymer having at least one of an epoxy group and a cyclic ether group in a side chain with an acidic phosphorus compound, in which at least a portion of the acidic phosphorus compound groups may form a salt, from the viewpoint of being capable of forming a film having excellent colorant dispersibility and storage stability, and excellent heat resistance and solvent resistance.

[0085] The polymer having one or more selected from the structural unit represented by the general formula (I) and the structural unit represented by the general formula (I') preferably further has a solvent affinity site from the viewpoint of dispersibility. Among them, such a dispersant is preferably a graft copolymer having one or more selected from the structural unit represented by the general formula (I) and the structural unit represented by the general formula (I') and a structural unit represented by the following general formula (II), or a block copolymer having one or more selected from the structural unit represented by the general formula (I) and the structural unit represented by the general formula (I') and a structural unit represented by the following general formula (III), from the viewpoint of being able to form a film having excellent colorant dispersibility and storage stability, excellent heat resistance and solvent resistance.

[0086] [ka] (In general formula (II), L 2 is a direct bond or a divalent linking group, R 51 represents a hydrogen atom or a methyl group, and Polymer represents a polymer chain having a constituent unit represented by the following general formula (IV). In general formula (III), R 52 is a hydrogen atom or a methyl group, R 53 is a hydrocarbon group, -[CH(R 54 )-CH(R 55 )-O] x2 -R 56 , -[(CH2) y2 -O] z2 -R 56 , -[CO-(CH2) y2 -O] z2 -R 56 , -CO-OR 56’ or -O-CO-R 56” A monovalent group represented by the formula: R 54 and R 55 each independently represents a hydrogen atom or a methyl group; R 56 is a hydrogen atom, a hydrocarbon group, -CHO, -CH2CHO or -CH2COOR 57 R is a monovalent group represented by the formula 56’ is a hydrocarbon group, -[CH(R 54)-CH(R 55 )-O] x2’ -R 56 , -[(CH2) y2’ -O] z2’ -R 56 , -[CO-(CH2) y2’ -O] z2’ -R 56 R is a monovalent group represented by the formula: 56” is an alkyl group having 1 to 18 carbon atoms, R 57 is a hydrogen atom or an alkyl group having a carbon number of 1 to 5. The hydrocarbon group may have a substituent. x2 and x2' are integers from 1 to 18, y2 and y2' are integers from 1 to 5, and z2 and z2' are integers from 1 to 18.

[0087] [ka] (In general formula (IV), R 61 is a hydrogen atom or a methyl group, R 62 is a hydrocarbon group, -[CH(R 63 )-CH(R 64 )-O] x3 -R 65 , -[(CH2) y3 -O] z3 -R 65 , -[CO-(CH2) y3 -O] z3 -R 65 , -CO-OR 66 or -O-CO-R 67 A monovalent group represented by the formula: R 63 and R 64 each independently represents a hydrogen atom or a methyl group; R 65 is a hydrogen atom, a hydrocarbon group, -CHO, -CH2CHO or -CH2COOR 68 A monovalent group represented by the formula: R 66 is a hydrocarbon group, -[CH(R 63 )-CH(R 64 )-O] x4 -R 65 , -[(CH2) y4 -O] z4 -R 65 , -[CO-(CH2) y4 -O]z4 -R 65 A monovalent group represented by the formula: R 67 is an alkyl group having 1 to 18 carbon atoms, R 68 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and the hydrocarbon group may have a substituent. n represents an integer of 5 to 200. x3 and x4 represent integers of 1 to 18, y3 and y4 represent integers of 1 to 5, and z3 and z4 represent integers of 1 to 18.

[0088] As a specific example of a graft copolymer having one or more selected from the structural units represented by the general formula (I) and the structural units represented by the general formula (I') and a structural unit represented by the general formula (II), or a block copolymer having one or more selected from the structural units represented by the general formula (I) and the structural units represented by the general formula (I') and a structural unit represented by the general formula (III), the graft copolymers and block copolymers described in JP 2017-002191 A and the like can be given as suitable examples.

[0089] In the present disclosure, the dispersant may be used alone or in combination of two or more. The content of the dispersant is appropriately selected depending on the type of colorant used, etc. In the colorant dispersion liquid of the present disclosure, the dispersant is usually in the range of 5 to 200 parts by mass, preferably 10 to 100 parts by mass, and more preferably 20 to 80 parts by mass, relative to 100 parts by mass of the colorant. If the content is within the above range, the colorant can be uniformly dispersed. In addition, in the composition described later, the blending ratio of the binder component is not relatively decreased, and a film having sufficient hardness can be formed. In the colorant dispersion of the present disclosure, the content of the dispersant is usually within the range of 1 to 50% by mass, and preferably 1 to 20% by mass, based on the total amount of the dispersion, from the viewpoints of dispersibility and dispersion stability.

[0090] <Solvent> The colorant dispersion according to the present disclosure uses the squarylium colorant dispersed as particles (aggregates) in a solvent. The colorant is a salt-forming compound of the specific dye and heteropolyacid, and is therefore poorly soluble in organic solvents. The salt-forming compound colorant used in the present disclosure is excellent in light resistance when dispersed in a solvent while maintaining its aggregated state. The solvent used in the present disclosure is a solvent that does not substantially dissolve the salt-forming compound colorant or a solvent that is poorly soluble in the salt-forming compound, and is preferably a solvent in which the solubility of the colorant at 23° C. is 0.1 (mg / 10 g solvent) or less. Among these, a solvent in which the solubility of the colorant at 23° C. is 0.01 (mg / 10 g solvent) or less is preferred, and a solvent in which the colorant does not substantially dissolve is more preferred.

[0091] In the present disclosure, a solvent in which the solubility of the squarylium colorant at 23° C. is 0.1 (mg / 10 g solvent) or less can be determined simply by the following evaluation method. 10 g of the solvent to be evaluated is added to a 20 mL sample vial, and 0.1 g of the coloring material is added. The vial is then covered and shaken well for 20 seconds, after which it is left to stand in a water bath at 23°C for 10 minutes. 5 g of the supernatant is filtered to remove insoluble matter. The filtrate obtained is further diluted 1000 times, and the absorption spectrum of the resulting solution is measured using a 1 cm cell with an ultraviolet-visible-near infrared spectrophotometer (e.g., Shimadzu UV-3100PC) to determine the absorbance at the maximum absorption wavelength. If the absorbance at the maximum absorption wavelength is less than 2, the solvent can be evaluated as a solvent (difficult to dissolve) in the coloring material at 23°C with a solubility of 0.1 (mg / 10 g solvent) or less.

[0092] In the above evaluation method, the obtained filtrate is not diluted, and the absorption spectrum is measured in the same manner as above to determine the absorbance at the maximum absorption wavelength. If the absorbance at the maximum absorption wavelength is less than 2, the solvent can be evaluated as a solvent that does not substantially dissolve the coloring material, which is the salt-forming compound.

[0093] The solvent in which the solubility of the squarylium colorant at 23°C is 0.1 (mg / 10 g solvent) or less is not particularly limited as long as it is a solvent that does not substantially dissolve the squarylium colorant or is poorly soluble in the squarylium colorant, and may be appropriately selected from solvents that do not react with the components in the colorant dispersion and can dissolve or disperse them.

[0094] In the colorant dispersion liquid of the present disclosure, it is preferable to use an ester-based solvent from the viewpoint of dispersion stability. Examples of ester-based solvents include ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethyl lactate, methoxyethyl acetate, propylene glycol monomethyl ether acetate, 3-methoxy-3-methyl-1-butyl acetate, 3-methoxybutyl acetate, methoxybutyl acetate, ethoxyethyl acetate, and ethyl cellosolve acetate. These solvents may be used alone or in combination of two or more kinds.

[0095] The colorant dispersion of the present disclosure is prepared by using the above-mentioned solvent in a ratio of usually 50 to 95 mass %, preferably 60 to 85 mass %, based on the total amount of the colorant dispersion including the solvent. If the amount of the solvent is too small, the viscosity increases and the dispersibility is likely to decrease. If the amount of the solvent is too large, the colorant concentration decreases, and depending on the application, there is a risk that sufficient absorption effect of light of a specific wavelength cannot be obtained.

[0096] <Other ingredients> The colorant dispersion of the present disclosure may further contain a dispersion aid resin and other components, if necessary. Examples of the dispersion-assisting resin include an alkali-soluble resin, which may have the effect of reducing the amount of dispersant required by stabilizing the dispersion due to the steric hindrance of the alkali-soluble resin, which may make it difficult for colorant particles to come into contact with each other, and thus stabilizing the dispersion. Examples of other components include surfactants for improving wettability, silane coupling agents for improving adhesion, defoamers, anti-cision agents, antioxidants, anti-aggregation agents, and ultraviolet absorbers.

[0097] <Method of manufacturing colorant dispersion liquid> The colorant dispersion of the present disclosure can be prepared by mixing the dispersant in the solvent, stirring to prepare a dispersant solution, and then mixing the colorant according to the present disclosure and other compounds as necessary in the dispersant solution and dispersing them using a dispersing machine. The colorant dispersion of the present disclosure may also be prepared by mixing the colorant and the dispersing agent in a solvent and dispersing them using a known dispersing machine.

[0098] Examples of dispersing machines for carrying out the dispersion treatment include roll mills such as two-roll and three-roll, ball mills such as ball mills and vibration ball mills, and bead mills such as paint conditioners, continuous disk bead mills, and continuous annular bead mills. As a preferred dispersion condition for the bead mill, the diameter of the beads used is preferably 0.03 to 2.00 mm, and more preferably 0.10 to 1.0 mm.

[0099] Specifically, preliminary dispersion is performed using zirconia beads having a relatively large bead diameter of 2 mm, and then main dispersion is performed using zirconia beads having a relatively small bead diameter of 0.1 mm. After dispersion, it is preferable to filter the mixture using a membrane filter of 0.1 to 0.5 μm.

[0100] In the present disclosure, the dispersion time for dispersing using a known dispersing machine is appropriately adjusted and is not particularly limited. For example, from the viewpoint of finely pulverizing the coloring material and realizing high absorbency for light in unnecessary wavelength regions, it is preferable to set the dispersion time to 5 to 40 hours. In this manner, a colorant dispersion liquid having excellent dispersibility of colorant particles is obtained.

[0101] The average dispersed particle size of the colorant used in the present disclosure in the colorant dispersion liquid is not particularly limited and may be appropriately set depending on the application, but is preferably within the range of 10 to 150 nm, more preferably within the range of 20 to 125 nm, from the viewpoint of excellent light resistance and heat resistance. When the average dispersed particle size of the colorant is within the above range, the surface coated with the colorant dispersion liquid of the present disclosure exhibits uniform and excellent absorption performance against light in an unnecessary wavelength range. The average dispersed particle size of the colorant in the colorant dispersion is the dispersed particle size of the colorant particles dispersed in a dispersion medium containing at least a solvent, and is measured by a laser light scattering particle size distribution meter. The particle size can be measured by diluting the colorant dispersion with the solvent used in the colorant dispersion to a concentration that can be measured by the laser light scattering particle size distribution meter (for example, 1000 times), and measuring the particle size at 23°C by dynamic light scattering using a laser light scattering particle size distribution meter (for example, a nano track particle size distribution measuring device UPA-EX150 manufactured by Nikkiso Co., Ltd.). The average dispersed particle size here is the volume average particle size.

[0102] The colorant dispersion can be used as a preparatory product for preparing the composition described later. That is, the colorant dispersion is a colorant dispersion having a high ratio of (mass of colorant content in the composition) / (mass of solid content other than colorant content in the composition) that is preparatoryly prepared in a stage prior to the preparation of the composition described later. Specifically, the ratio of (mass of colorant content in the composition) / (mass of solid content other than colorant content in the composition) is usually 1.0 or more. By mixing the colorant dispersion with at least a binder component, a composition with excellent dispersibility can be prepared.

[0103] III. Ink Composition The ink composition according to one embodiment of the present disclosure is characterized by containing the squarylium colorant according to the present disclosure and a binder component.

[0104] The ink composition of the present disclosure uses the squarylium colorant of the present disclosure, which has excellent heat resistance and light resistance, in combination with a binder component, making it possible to form a film or molded article that has excellent heat resistance and light resistance and is capable of absorbing and reducing light in unnecessary wavelength regions. The ink composition of the present disclosure contains at least the squarylium colorant of the present disclosure and a binder component, and may contain other components as necessary. The ink composition of the present disclosure may be used by combining the colorant dispersion with a binder component. In this case, the ink composition of the present disclosure contains the squarylium colorant of the present disclosure, a binder component, a dispersant, and a solvent. Hereinafter, each component of the composition of the present disclosure will be described in detail. Note that, as for the components that can be contained in the colorant dispersion liquid according to the present disclosure, the same ones as those described in the section on the colorant dispersion liquid above can be used, so the description here will be omitted. However, the solvent is not limited to the above-mentioned preferred solvents, and a solvent that has high solubility for the binder component and other components added as necessary can be appropriately selected and used.

[0105] <Binder components> The ink composition of the present disclosure contains a binder component in order to impart film-forming properties, moldability, and adhesion to the surface to be coated. The binder component preferably contains at least a resin. The resin may be any of an adhesive, a thermoplastic resin, a thermosetting resin, and a photocurable resin. The resin is not limited to a high molecular weight compound or a polymer, but may be a low molecular weight compound or a monomer. In addition, the resin may be particles of a synthetic resin that constitutes a resin emulsion. The binder component is preferably light-transmitting, and when the binder component is used alone to form a film having a thickness of 3 μm, the transmittance in the visible light region is preferably 80% or more, more preferably 84% or more. The transmittance can be measured in accordance with JIS K7361-1:1997 (Test method for total light transmittance of plastic transparent materials).

[0106] Examples of the adhesive include acrylic adhesives, silicone adhesives, urethane adhesives, polyvinyl butyral adhesives, ethylene-vinyl acetate adhesives, polyvinyl ether, saturated amorphous polyesters, and melamine resins. Examples of thermoplastic resins include acrylic resins such as poly(meth)acrylic acid, poly(meth)acrylic acid esters, polyacrylonitrile, and polyacrylamide; polystyrene resins; cellulose resins such as nitrocellulose, ethyl cellulose, and triacetyl cellulose; polyester resins such as polyethylene terephthalate; polycarbonate resins; thermoplastic urethane resins; modified olefin resins such as chlorinated polyethylene and chlorinated polypropylene; vinyl resins such as vinyl acetate resin, vinyl chloride-vinyl acetate copolymer, and butyral resin, polyamide resins; polyimide resins; and olefin resins such as cyclic polyolefins and polyolefins.

[0107] In order to impart sufficient hardness to the coating film, it is preferable to contain a curable binder component containing a thermosetting resin or a photocurable resin. The curable binder component is not particularly limited, and any conventionally known curable binder component can be appropriately used. As the curable binder component, for example, a photocurable binder component containing a photocurable resin that can be polymerized and cured by visible light, ultraviolet light, electron beam, or the like, or a thermosetting binder component containing a thermosetting resin that can be polymerized and cured by heating can be used.

[0108] As the thermosetting binder, a combination of a compound having two or more thermosetting functional groups in one molecule and a curing agent is usually used, and a catalyst capable of promoting the thermosetting reaction may be added. As the thermosetting functional group, an epoxy group, an oxetanyl group, an isocyanate group, an ethylenically unsaturated bond, etc. are listed. As the thermosetting functional group, an epoxy group is preferably used. As a specific example of the thermosetting binder component, for example, those described in International Publication No. 2012 / 144521 can be listed.

[0109] On the other hand, as the photocurable binder, a combination of a compound having one or more photocurable functional groups in one molecule and a photoinitiator is usually used. These compounds and photoinitiators can be appropriately selected from conventionally known compounds and photoinitiators. Examples of the photocurable functional group include a radically polymerizable ethylenically unsaturated bond-containing group, a cationic polymerizable epoxy group, and an oxetanyl group. As the photocurable functional group, an ethylenically unsaturated bond-containing group is preferably used, and specific examples thereof include a vinyl group and a (meth)acryloyl group. The number of photocurable functional groups that the photocurable compound has in one molecule is preferably 2 or more, and more preferably 3 or more, from the viewpoint of improving hardness. As the radical polymerizable compound, from the viewpoint of high reactivity, a compound having a (meth)acryloyl group is preferred, and a compound called a polyfunctional (meth)acrylate monomer having two or more (meth)acryloyl groups in one molecule, or an oligomer having a molecular weight of several hundred to several thousand and having two or more (meth)acryloyl groups in a molecule called urethane (meth)acrylate, polyester (meth)acrylate, epoxy (meth)acrylate, melamine (meth)acrylate, polyfluoroalkyl (meth)acrylate, or silicone (meth)acrylate, can be preferably used, and a polyfunctional (meth)acrylate polymer having two or more (meth)acryloyl groups in a side chain of an acrylate polymer can also be preferably used. Among them, from the viewpoint of improving hardness, a polyfunctional (meth)acrylate monomer having two or more (meth)acryloyl groups in one molecule can be preferably used.

[0110] Examples of the resin emulsion include acrylic emulsion, styrene-acrylic emulsion, vinyl acetate emulsion, and ethylene-vinyl acetate emulsion.

[0111] Furthermore, when the film has a pattern and a photolithography process is used in forming the film, a photosensitive binder component having alkali developability is preferably used. The photosensitive binder component may be a positive-type photosensitive binder component or a negative-type photosensitive binder component. The positive-type photosensitive binder component may be, for example, a system containing an alkali-soluble resin and an o-quinone diazide group-containing compound as a photosensitivity-imparting component, and the alkali-soluble resin may be, for example, a polyimide precursor.

[0112] As the negative photosensitive binder component, a system containing at least an alkali-soluble resin, a polyfunctional monomer, and a photoinitiator is preferably used. Specific examples of the alkali-soluble resin, the polyfunctional monomer, and the photoinitiator include those described in International Publication No. 2012 / 144521.

[0113] <Optional addition ingredients> The ink composition of the present disclosure may contain other light absorbing compounds and various additives as necessary, as long as the object of the present disclosure is not impaired. Examples of other light-absorbing compounds include compounds having a desired absorption in the visible light region, such as squarylium compounds, anthraquinone compounds, phthalocyanine compounds, methine compounds, azomethine compounds, oxazine compounds, azo compounds, styryl compounds, coumarin compounds, porphyrin compounds, dibenzofuranone compounds, diketopyrrolopyrrole compounds, rhodamine compounds, xanthene compounds, and pyrromethene compounds.

[0114] Examples of additives include polymerization terminators, chain transfer agents, leveling agents, plasticizers, surfactants, defoamers, silane coupling agents, UV absorbers, adhesion promoters, antistatic agents, fillers, etc. The additives may further include inorganic or organic fine particles for adjusting hardness or refractive index, antiglare agents, antifouling agents, flame retardants, antioxidants, light stabilizers, surface modifiers, etc.

[0115] <Ratio of each component in the composition> The total content of the specific colorant used in the present disclosure and other colorants blended as necessary may be appropriately selected according to the purpose and is not particularly limited, but may be, for example, 0.01% by mass or more, 0.05% by mass or more, 0.1% by mass or more, 0.2% by mass or more, 20% by mass or less, or 10% by mass or less, based on the total solid content of the composition. If the colorant is too small, it may be difficult to obtain the desired absorbency for light in an unnecessary wavelength range. If the colorant is too large, the film properties such as adhesion to the substrate when the composition is applied to the substrate and cured, surface roughness of the film, and film hardness may be insufficient. In addition, in the present disclosure, the solid content is everything other than the above-mentioned solvent, and includes polyfunctional monomers that are liquid at 25 ° C. In addition, when a dispersant is used, the content of the dispersant may be appropriately adjusted within a range in which the colorant can be uniformly dispersed. For example, it is preferable to use 10 to 150 parts by mass with respect to 100 parts by mass of the colorant, more preferably to mix at a ratio of 15 to 45 parts by mass with respect to 100 parts by mass of the colorant, and even more preferably to mix at a ratio of 15 to 40 parts by mass with respect to 100 parts by mass of the colorant. In addition, the content of the dispersant is preferably within a range of 0.01 to 30% by mass with respect to the total solid content of the composition, and more preferably within a range of 0.03 to 10% by mass. If the content of the dispersant is less than 0.01% by mass with respect to the total solid content of the composition, the effect of using the dispersant may not be fully exhibited, and if it exceeds 30% by mass, it may cause a decrease in curability and developability. The binder components are preferably blended in such a manner that their total content is 24 to 94 mass %, or 40 to 90 mass %, relative to the total solid content of the composition. When a solvent is used, the content thereof may be appropriately adjusted in terms of dispersibility of the colorant, coatability of the composition, etc. The content of the solvent is usually preferably within a range of 65 to 95% by mass, and more preferably within a range of 75 to 88% by mass, based on the total amount of the composition including the solvent.

[0116] <Production of Ink Composition> The method for producing the ink composition is not particularly limited. When a pressure-sensitive adhesive or a thermoplastic resin is used as the binder component, the specific coloring material used in the present disclosure may be added to the pressure-sensitive adhesive or the thermoplastic resin and kneaded for use. Alternatively, a method may be used in which the binder component and various additive components used as desired are added to a solvent, mixed, and then the coloring material used in the present disclosure is added thereto and mixed. In addition, when preparing a composition using the colorant dispersion liquid according to the present disclosure, for example, a method in which the colorant dispersion liquid according to the present disclosure, a binder component, and various additive components used as desired are simultaneously charged into a solvent and mixed, or a method in which the binder component and various additive components used as desired are added to a solvent, mixed, and then the colorant dispersion liquid according to the present disclosure is added thereto and mixed, can be mentioned.

[0117] <Film or Molded Article> The film or molded article according to one embodiment of the present disclosure is a film or molded article containing at least one of the ink composition according to one embodiment of the present disclosure and a cured product thereof. The film or molded article according to one embodiment of the present disclosure contains at least one of the ink composition according to one embodiment of the present disclosure and a cured product thereof, and thus it is possible to form a film or molded article having excellent heat resistance and light resistance, capable of suppressing light in unnecessary wavelength regions. The film or molded article has good light resistance, reduced side absorption, and improved color purity and brightness. The film of the present disclosure may have a pattern or may be a film (flat film) without a pattern. The film of the present disclosure may be used in a state in which it is laminated on a support, or may be used by peeling the film from the support.

[0118] The film of the present disclosure may be called a sheet or plate, and the film thickness can be appropriately adjusted depending on the purpose. The film thickness may be 200 μm or less, and may be 150 μm or less. In particular, from the viewpoint of ensuring total light transmittance, the film of the present disclosure is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 50 μm or less. The lower limit of the film thickness is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.3 μm or more.

[0119] An example of a method for producing a film according to an embodiment of the present disclosure includes a method including a step of forming a composition layer on a support using the ink composition according to an embodiment of the present disclosure, and, if necessary, a step of curing the composition layer.

[0120] The support is not particularly limited, and may be made of a material such as glass, silicon, polycarbonate, polyester, polyacrylic, aromatic polyamide, polyamideimide, polyimide, cycloolefin polymer, cellulose acylate, or other optical components used in display devices.

[0121] The method of applying the ink composition to the support can be appropriately selected and used as a known method, for example, gravure coating, reverse coating, knife coating, dip coating, spray coating, air knife coating, spin coating, roll coating, printing, immersion and pulling up, curtain coating, die coating, casting, bar coating, extrusion coating, E-type coating, and other coating methods, various printing methods such as ejection printing such as inkjet and nozzle jet, flexographic printing, screen printing, gravure printing, reverse offset printing, and metal mask printing, transfer methods using a mold, and nanoimprinting, and the like can be mentioned.

[0122] The composition layer applied onto the support can be turned into a film by appropriately removing (drying) the solvent as necessary.

[0123] In the step of curing the composition layer, a known method such as applying at least one of heating and light irradiation may be appropriately selected depending on the curing property of the binder component contained in the composition, and the binder component may be cured. After the film is produced, the support may be removed.

[0124] When the film of one embodiment of the present disclosure has a pattern, the production method further includes a method including a step of forming a pattern on the composition layer by photolithography or dry etching. The photolithography method or dry etching method is not particularly limited, and a known method can be appropriately selected and applied in accordance with the binder component contained in the composition.

[0125] A method for producing the molded article according to one embodiment of the present disclosure includes, for example, a method of hot molding using the ink composition according to one embodiment of the present disclosure. As the molding method, a known method can be appropriately selected and applied according to the binder component contained in the ink composition.

[0126] The film or molded article according to one embodiment of the present disclosure can be used in various devices such as solid-state imaging devices, such as CCDs (charge-coupled devices) and CMOSs ​​(complementary metal oxide semiconductors), in addition to image display devices. The film or molded article according to one embodiment of the present disclosure can be suitably used in optical filters, which are described below, for the purpose of transmitting or reflecting and absorbing light rays and providing various effects, and can also be used in recording media that utilize absorption heat of selective wavelengths. For example, the film or molded article according to one embodiment of the present disclosure can also be used to suppress external light reflection in organic EL displays that do not include a circular polarizer (circular polarizer-less), such as quantum dot light-emitting diodes (QLEDs). In addition, the film or molded article according to one embodiment of the present disclosure can also be used as an optical material for transmitting or reflecting and absorbing light rays and for the purpose of providing various effects. As an optical material, it can also be used for lenses such as plastic eyeglass lenses, sunglasses lenses, and goggles.

[0127] IV. Optical Filters An optical filter according to one embodiment of the present disclosure is an optical filter containing the squarylium color material according to the present disclosure. The optical filter of one embodiment of the present disclosure may be a single-layer structure consisting of a layer containing the squarylium color material of the present disclosure, or may be a laminate having a multilayer structure including a layer containing the squarylium color material of the present disclosure. The layer containing the squarylium colorant of the present disclosure may be the same as the film of the embodiment of the present disclosure described above. In an optical filter according to one embodiment of the present disclosure, the layer containing the squarylium color material of the present disclosure may be one layer or two or more layers, and the squarylium color materials of the present disclosure contained in the two or more layers may be the same or different.

[0128] An optical filter according to an embodiment of the present disclosure, which contains the squarylium color material of the present disclosure, may be used, for example, as a specific wavelength absorption filter that selectively absorbs light in an unnecessary wavelength range, a color correction filter that adjusts color tone, or the like. The optical filter is applied to, for example, a display device, a lighting device, a window material, and the like.

[0129] The optical filter according to one embodiment of the present disclosure may include a support, and may further include a pressure-sensitive adhesive layer or a peelable release film. The support, pressure-sensitive adhesive layer, and peelable release film may be appropriately selected from conventionally known structures. Specific examples of the pressure-sensitive adhesive layer and the peelable release film include those described in JP-A-2009-251511.

[0130] The optical filter according to an embodiment of the present disclosure may further include other functional layers. Examples of other functional layers include a polarizer, a retardation film, a protective film, an antireflection layer, an antiglare layer, an antifouling layer, an antistatic layer, a hard coat layer, an adhesive layer, etc. As the polarizer, the retardation film, the protective film, the antireflection layer, the antiglare layer, the antifouling layer, the antistatic layer, the hard coat layer, the adhesive layer, and the adhesive layer, each of them can adopt a conventionally known configuration.

[0131] In the optical filter according to one embodiment of the present disclosure, the layer containing the squarylium colorant of the present disclosure may further have another function, for example, a function possessed by one or more layers selected from the group consisting of a protective film, an antireflection layer, an antiglare layer, an antifouling layer, an antistatic layer, a hard coat layer, an adhesive layer, and an adhesive layer.

[0132] The optical filter according to an embodiment of the present disclosure may contain the squarylium color material of the present disclosure in a configuration of a conventionally known optical filter, for example, an optical filter in which at least one of the functional layers contains the squarylium color material of the present disclosure.

[0133] The optical filter of one embodiment of the present disclosure may be a display surface film that is placed on the viewer-side surface of a display panel in a display device. The display surface film usually has a surface functional layer necessary for the display surface, and may further have a support for the surface functional layer, and a surface functional layer, an adhesive layer, or an adhesive layer on the side of the support opposite to the surface functional layer. Examples of the surface functional layer include at least one of a polarizer, a retardation film, a protective film, a hard coat layer, an antireflection layer, an antiglare layer, an antifouling layer, and an antistatic layer. The surface functional layer may include a layer having the functions of a hard coat layer, in particular, from the viewpoint of improving the surface hardness of the display surface film and enabling the formation of a coating film by a solution process, and may include a layer having at least the functions of a hard coat layer and an anti-reflection layer.

[0134] The hard coat layer is generally a layer that is harder than the protective film and provides at least scratch resistance. The hard coat layer preferably exhibits a hardness of "H" or more in the pencil hardness test (load of 4.9 N) specified in JIS K5600-5-4:1999. The hard coat layer preferably has an anti-reflection function and an anti-glare function for improving visibility, and may further have an anti-soiling function and an anti-static function. The hard coat layer can be appropriately selected from hard coat layers used in optical filters or optical films of conventionally known display devices. For example, the hard coat layers described in International Publication No. 2012 / 018087, International Publication No. 2011 / 065531, JP-A-2018-51918, etc. can be used as the hard coat layer, and the contents of these publications are incorporated herein by reference, but are not limited thereto.

[0135] The configurations of the polarizer, retardation film, protective film, antireflection layer, antiglare layer, antifouling layer, and antistatic layer used in the surface functional layer can be appropriately selected and used from conventionally known configurations. For example, reference can be made to Japanese Patent No. 6070195, Japanese Patent No. 6040936, JP 2017-21293, JP 2013-142817, JP 2011-90301, etc.

[0136] Fig. 1 is a schematic cross-sectional view showing an example of the optical filter of the present disclosure. As shown in Fig. 1, the optical filter 40 can function as a display surface film, and is a laminate having a surface functional layer 30 on one side of the support 1 and an adhesive layer or bonding layer 2 on the other side of the support 1. On the other side of the support 1, a surface functional layer 30 may be further provided between the support 1 and the adhesive layer or bonding layer 2 (not shown). Fig. 1 is merely an example, and the optical filter of the present disclosure is not limited to this configuration. The optical filter of the present disclosure may consist of only a film corresponding to the surface functional layer 30. However, the surface functional layer 30 may be a single layer or a laminate of two or more layers. When the surface functional layer 30 is a laminate, for example, an anti-reflection layer made of a low refractive index layer and a high refractive index layer, and a hard coat layer are laminated in this order.

[0137] 1 may contain the squarylium color material of the present disclosure in any one of the surface functional layer 30, the support 1, and the adhesive layer or the bonding layer 2, or in two or more layers. In order to further improve light resistance, the optical filter of the present disclosure may contain the squarylium color material of the present disclosure in a layer located closer to the display element than the surface functional layer 30 containing an ultraviolet absorber or the support 1 containing an ultraviolet absorber. The surface functional layer 30, support 1, and adhesive layer or bonding layer 2 containing the squarylium colorant of the present disclosure can be manufactured in the same manner as in the manufacturing method of the film of one embodiment of the present disclosure, by appropriately selecting the binder component and, if necessary, other necessary components. The material of the support 1 is preferably appropriately selected from the thermoplastic resins among the binder components of the ink composition of the embodiment of the present disclosure described above, and may be the same as the support of the film of the embodiment of the present disclosure described above. Among them, triacetyl cellulose film (TAC film) and cycloolefin polymer film are preferably used as the support 1 from the viewpoint of optical properties. Furthermore, as the material for the adhesive layer or the bonding layer 2, a binder component having a high transmittance in the visible light region may be appropriately selected from among the adhesives or curable binder components of the binder components of the ink composition of one embodiment of the present disclosure described above.

[0138] The squarylium color material of the present disclosure may be contained in the surface functional layer 30 because existing manufacturing processes for display devices can be used. The squarylium colorant of the present disclosure may be contained in, for example, the hard coat layer of the surface functional layer 30. As the material for the hard coat layer, a binder component having a high transmittance in the visible light region may be appropriately selected from among the photocurable binder components of the ink composition of one embodiment of the present disclosure described above.

[0139] In the optical filter used as the display surface film of the present disclosure, the total thickness of the surface functional layers may be appropriately selected and is, for example, 10 to 150 μm, but is usually 20 to 100 μm. In the optical filter used as the display surface film of the present disclosure, when a support is provided, the thickness of the support may be appropriately selected and is, for example, 10 to 150 μm, but is usually 20 to 100 μm. In the optical filter used as the display surface film of the present disclosure, when an adhesive layer or bonding layer is provided, the thickness of the adhesive layer or bonding layer may be appropriately selected and is, for example, 10 to 150 μm, but is usually 20 to 100 μm.

[0140] The optical filter used as the display surface film of the present disclosure may have a transmittance in the visible light region (380 nm to 750 nm) of 80% or more, or may have a transmittance of 90% or more, as measured in accordance with JIS K7361-1:1997.

[0141] By using the squarylium color material of the present disclosure, the optical filter of the present disclosure can be an optical filter having a maximum absorption wavelength (minimum transmission wavelength) in a wavelength region around 550 to 630 nm, and can selectively absorb wavelengths around 550 to 630 nm. For example, by arranging such an optical filter of the present disclosure on the viewing side of a display element of a display device, it is possible to selectively absorb wavelengths around 550 to 630 nm from light incident on the optical filter, and the light transmitted through the optical filter can have improved color purity of green light and red light compared to the light incident on the optical filter.

[0142] V.Display device A display device according to one embodiment of the present disclosure is a display device including the optical filter according to the one embodiment of the present disclosure. The optical filter of the present disclosure may be incorporated into a display device and used in any manner, and the manner of incorporation is not particularly limited. Examples of the display element constituting the display device include a liquid crystal display element, an EL (inorganic EL, organic EL) display element, a plasma display element, an electronic paper display element, an LED display element (micro LED, etc.), a display element using a quantum dot light-emitting diode (QLED), etc. That is, examples of the display device include a liquid crystal display device, an EL (inorganic EL, organic EL) display device, a plasma display device, an electronic paper display device, an LED display device (micro LED, etc.), a display device using a quantum dot light-emitting diode (QLED), etc. In the case of a liquid crystal display device, it is necessary to place a backlight on the opposite side of the display element from the molded body. In particular, a display device according to one embodiment of the present disclosure is preferably a display device including an optical filter containing the squarylium color material of the present disclosure arranged on the viewing side of a display element, in that the optical filter has excellent heat resistance and light resistance, is capable of absorbing and reducing light in unnecessary wavelength regions, and can increase the color purity of the displayed color and suppress external light reflection. The optical filter containing the squarylium color material of the present disclosure may be provided as a display surface film.

[0143] An example of a display device according to an embodiment of the present disclosure will be described with reference to the drawings. 2, the image display device 100 mainly includes a display panel 10 for displaying an image, and a backlight device 20 arranged on the rear side of the display panel 10. In this embodiment, since the display panel 10 is a liquid crystal display panel, the image display device 100 includes the backlight device 20, but depending on the type of display panel (display element), the image display device 100 may not include the backlight device 20.

[0144] (Display panel) As shown in Fig. 2, the display panel 10 has a structure in which a protective film 11, a polarizer 12, a protective film 13, a light-transmitting adhesive layer 14, a display element 15, a light-transmitting adhesive layer 16, a protective film 17, a polarizer 18, a light-transmitting adhesive layer 16', a protective film 19, and a surface functional layer 30 are laminated in this order from the backlight device 20 side toward the viewer side. In Fig. 2, a laminate of the light-transmitting adhesive layer 16', the protective film 19, and the surface functional layer 30 corresponds to a display surface film 40. The optical filter of the present disclosure may be the display surface film 40, or may be a laminate in which the light-transmitting adhesive layer 16, the protective film 17, the polarizer 18, the light-transmitting adhesive layer 16', the protective film 19, and the surface functional layer 30 are laminated in this order. The display panel 10 only needs to include the display element 15, and may not include the protective film 11 or the like.

[0145] The display element 15 in Fig. 2 is a liquid crystal display element. However, the display element 15 is not limited to a liquid crystal display element, and may be, for example, the display element as described above. The liquid crystal display element has a liquid crystal layer, an alignment film, an electrode layer, a color filter, etc., disposed between two glass substrates. The protective film, polarizer, and light-transmitting adhesive layer may be appropriately selected from conventionally known materials. Suitable examples of the protective film include a triacetyl cellulose film (TAC film) and a cycloolefin polymer film. As the light-transmitting adhesive layer, for example, an adhesive sheet such as OCA (Optical Clear Adhesive) can be suitably used, and it may also be a cured product of a liquid composition for a curable adhesive layer containing a polymerizable compound such as OCR (Optically Clear Resin).

[0146] 2 is a layer located on the surface of a display panel in a display device, and may be one layer or two or more layers that provide various functions. The surface functional layer 30 may be the same as the surface functional layer described in the optical filter of the embodiment of the present disclosure, and may be a layer having at least one function of a hard coat layer, an antireflection layer, an antiglare layer, an antifouling layer, and an antistatic layer.

[0147] (Backlight device) The backlight device 20 illuminates the display panel 10 from the rear side of the display panel 10. A known backlight device can be used as the backlight device 20, and the backlight device 20 may be either an edge-light type or a direct type backlight device. Examples of the light source for the backlight include LEDs and CCFLs (cold cathode fluorescent lamps), and a backlight using quantum dots as the light source tends to improve color reproducibility.

[0148] In the display device according to one embodiment of the present disclosure, the location of the optical filter is not particularly limited as long as it is disposed between the light source serving as the backlight and the viewer of the display device. In one embodiment of the display device of the present disclosure, for example, in FIG. 2, the light-transmitting adhesive layer 16 or protective film 17 present between the display element 15 and the polarizer 18 may be an optical filter containing the squarylium color material of the present disclosure, or the protective film 11, protective film 13, or light-transmitting adhesive layer 14 may be an optical filter containing the squarylium color material of the present disclosure.

[0149] Moreover, the display device according to one embodiment of the present disclosure is provided with an optical filter containing the squarylium color material of the present disclosure, and therefore can be suitably used in a display device using a white LED or a blue LED as a light source. The use of an optical filter containing the squarylium color material of the present disclosure can suitably remove light in the vicinity of 570 to 590 nm, and correct the chromaticity of the white light to a preferred one. Therefore, the display device may be a display device having a light source of a blue LED that obtains white light by combining the blue light of a blue LED and a yellow light emitting phosphor, or a display device having a blue LED and a green and red light emitting phosphor. The use of an optical filter containing the squarylium color material of the present disclosure can suitably remove light in the vicinity of 570 to 590 nm, and improve the color purity of the green light and red light. Therefore, the display device may be a display device having a blue LED as a light source.

[0150] In addition, since the display device according to one embodiment of the present disclosure includes an optical filter containing the squarylium color material of the present disclosure, it can be suitably used in a display device that does not include a circular polarizer (circular polarizer-less) and uses a quantum dot light-emitting diode (QLED) as a light source. By using an optical filter containing the squarylium color material of the present disclosure, it is possible to reduce external light reflection while suppressing a decrease in luminous efficiency, even in a QLED display device that does not include a circular polarizer (circular polarizer-less).

[0151] The display device according to one embodiment of the present disclosure is not limited to the above-mentioned examples, and may be any conventionally known configuration that is appropriately selected and adopted. The display device according to the embodiment of the present disclosure may further include a touch panel, for example, on the viewer side of the display panel 10 in FIG. 2, via, for example, a light-transmitting adhesive layer.

[0152] Furthermore, without being limited to the above examples, a display device of one embodiment of the present disclosure may be adopted by appropriately selecting a conventionally known configuration, and in the display device, the optical filter of one embodiment of the present disclosure may be provided in a position suitable for reducing light in an unnecessary wavelength range, and may be set as appropriate. EXAMPLES

[0153] The present disclosure will be specifically described below with reference to examples, but the embodiments of the present disclosure are not limited to these examples. the below described 1 H-NMR measurements were carried out using AVANCE 400 manufactured by BRUKER. 1 The H-NMR measurement conditions are as follows. < 1 H-NMR measurement conditions> 5 mg of the sample was placed in an NMR sample tube with an inner diameter of 5 mm together with 0.7 mL of DMSO-d6 and tetramethylsilane as a chemical shift standard substance, and the measurement sample was prepared at room temperature. Probe: PA DUL 400S1 CHD-05 Z BTO PLUS Sample temperature: 25℃ Number of times accumulated: 64 Chemical shifts: The proton signal of tetramethylsilane is set at 0.00 ppm, and the chemical shifts of the signals due to other protons are based on this. The following MALDI-MS measurements were carried out using REFLEX II manufactured by BRUKER. Mass spectrometry was carried out using dithranol as a matrix agent. In the elemental analysis described below, organic trace element analysis was performed using CE440 manufactured by Exeter Analytical.

[0154] (Synthesis Example 1: Synthesis of squarylium dye 1) Squarylium dye 1 was synthesized according to the following scheme. (1) Synthesis of intermediate 1 The synthesis was carried out with reference to Penghui Ni et al, Org.Lett. 2019,21,3518-3522. Under an argon atmosphere, polyphosphoric acid (1.0 kg), 2'-bromoacetophenone (64.2 g, 323 mmol), and hydrazine hydrochloride (70.0 g, 484 mmol) were added to a 2 L flask and stirred at an external temperature of 105 ° C. After 3 hours, the reaction solution was poured into ice (2.22 kg) at room temperature. The obtained oily substance was washed with water four times. Then, the oily substance was extracted with toluene (1.1 L), and the insoluble matter was removed from the solution, and the solution was concentrated under reduced pressure. The obtained residue was purified by silica gel chromatography to synthesize intermediate 1 (yield 42.5 g, yield 48%).

[0155] (2) Synthesis of intermediate 2 Under an argon atmosphere, intermediate 1 (41.4 g, 152 mmol) and tetrahydrofuran (264 mL) were added to a 1 L flask and cooled to an internal temperature of 15°C. Next, dimethylaminopyridine (0.37 g, 3.04 mmol) and di-tert-butyl dicarbonate (36.5 g, 167 mmol) were added to the mixture, and triethylamine (17.7 g, 175 mmol) was added dropwise to the mixture over 5 minutes. After stirring at room temperature for 1 hour, the reaction solution was concentrated under reduced pressure, and the resulting residue was purified by silica gel chromatography to obtain intermediate 2 (yield 61.5 g, 90%).

[0156] (3) Synthesis of intermediate 3 Under an argon stream, intermediate 2 (41.0 g, 110 mmol), toluene (220 mL), 4-vinylpyridine (17.4 g, 165 mmol), and diisopropylethylamine (21.4 g, 165 mmol) were added to a 500 mL flask and stirred. The mixture was then heated to an internal temperature of 85°C, and tri-t-butylphosphonium tetrafluoroborate (0.64 g, 2.20 mmol) and tris(dibenzylideneacetone)dipalladium(0) (1.0 g, 1.10 mmol) were added to the mixture. The mixture was heated to an internal temperature of 100°C, and then stirred for 1 hour. The reaction solution was cooled to room temperature and purified by silica gel chromatography. The residue obtained after vacuum concentration was washed with heptane and filtered to obtain a powder of intermediate 3 (yield: 34.2 g, yield: 78%).

[0157] (4) Synthesis of intermediate 4 Intermediate 3 (34.0 g, 85.8 mmol), tetrahydrofuran (170 mL), and methanol (170 mL) were added to a 500 mL autoclave, and the reaction system was replaced with argon gas. Palladium / carbon (Pd content 5%, 3.4 g) was then added to the autoclave, and the system was pressurized with hydrogen gas (0.8 MPa). After the reaction was completed, the system was replaced with argon gas over 30 minutes, and the reaction liquid was filtered. The obtained filtrate was concentrated under reduced pressure to obtain intermediate 4 (yield: 35.3 g, yield: 100%).

[0158] (5) Synthesis of intermediate 5 Intermediate 4 (43.7 g, 119 mmol) and tetrahydrofuran (473 mL) were added to a 1 L flask and cooled to an internal temperature of 1°C. Then, 28% sodium methoxide / methanol solution (37.0 g, 192 mmol) was slowly added, the mixture was warmed to room temperature, and stirred for 1 hour. The reaction solution was then poured into 15% aqueous ammonium chloride solution (946 mL), and the reaction product was extracted with ethyl acetate (946 mL). The resulting organic layer was washed with water (946 mL) and concentrated under reduced pressure. Heptane was added to the resulting residue, and the precipitate was filtered to obtain intermediate 5 (yield: 26.9 g, yield: 76%).

[0159] (6) Synthesis of squarylium dye 1 Under an argon atmosphere, intermediate 5 (13.6 g, 45.4 mmol), squaric acid (2.5 g, 21.6 mmol), and isopropanol (1.7 L) were added to a 5 L flask, and then triethyl orthoformate (340 mL) was added. The internal temperature was raised to 82°C and stirred for 6 hours. The reaction solution was then cooled to 10°C, and the precipitated solid was collected by filtration. 2-propanol (300 mL) was added to the resulting solid (3.2 g), and the mixture was heated and washed for 30 minutes. The mixture was then cooled to room temperature, and the solid was collected by filtration to obtain squarylium dye 1 (yield: 3.2 g, 22%).

[0160] 1 H-NMR confirmed that the resulting compound had the structure of squarylium dye 1 shown below. 1 H NMR(400MHz,DMSO-d6):δ=13.05(br s,2H),8.86(br s,2H),8.23(br s,4H),7.49-7.18(m,14H),6.92(br s,4H),2.89-2.78(m,4H),2.75-2.57(m,4H). In addition, 1 The H-NMR spectrum is shown in Figure 6.

[0161] [ka]

[0162] (Synthesis Example 2: Synthesis of squarylium dye 2) (1) Synthesis of intermediate 6 Intermediate 1 was synthesized in the same manner as in Synthesis Example 1. Under an argon gas flow, intermediate 1 (5.5 g, 20.2 mmol) and dimethyl sulfoxide (55 mL) were added to a 200 mL flask and stirred. Then, potassium hydroxide (1.36 g, 24.2 mmol) and bromoethane (2.64 g, 24.2 mmol) were added to the mixture. The mixture was stirred at room temperature for 12 hours. The resulting reaction solution was then poured into ice water (110 mL), and the reaction product was extracted with toluene. The organic layer was washed with water (550 mL) and 10% saline (550 mL), and concentrated under reduced pressure. Heptane was added to the resulting residue, and the precipitate was collected by filtration to obtain intermediate 6 (5.1 g, 84% yield).

[0163] (2) Synthesis of squarylium dye 2 In the synthesis of squarylium dye 1 in Synthesis Example 1, squarylium dye 2 was synthesized according to the following scheme, except that an equimolar amount of intermediate 6 obtained above was used in place of intermediate 2. 1 The resulting compound was confirmed to have the structure of squarylium dye 2 shown below by H-NMR. 1 H NMR(400MHz,DMSO-d6):δ=9.08(br s,2H),8.35-8.21(m,4H),7.52-7.08(m,18H),6.82(br s,4H),3.97-3.78(m,2H),3.77-3.61(m,2H),3.82-3.56(m,4H),1.28-1.14(m,6H). Obtained 1 The H-NMR spectrum is shown in Figure 7.

[0164] [ka]

[0165] (Synthesis Example 3: Synthesis of squarylium dye 3) (1) Synthesis of intermediate 9 Intermediate 1 was synthesized in the same manner as in Synthesis Example 1. Under an argon gas flow, intermediate 1 (4.4 g, 16.0 mmol) and dimethyl sulfoxide (43 mL) were added to a 200 mL flask and stirred. Then, potassium hydroxide (1.0 g, 17.6 mmol) and cyclohexylmethyl bromide (3.1 g, 26.6 mmol) were added to the mixture, and the mixture was stirred at room temperature for 12 hours. The resulting reaction solution was then poured into ice water (130 mL), and the reaction product was extracted with ethyl acetate. The organic layer was washed with water (65 mL) and concentrated under reduced pressure. The resulting residue was purified using a silica gel column to obtain intermediate 9 (5.4 g, yield 91%).

[0166] [ka]

[0167] (2) Synthesis of squarylium dye 3 Squarylium dye 3 was synthesized in the same manner as in Synthesis Example 2, except that an equimolar amount of intermediate 9 obtained above was used instead of intermediate 6 in the synthesis of squarylium dye 2 in Synthesis Example 2. 1 H-NMR confirmed that the resulting compound had the structure of squarylium dye 3 shown below. 1 H NMR(400MHz,DMSO-d6):δ=9.05(br s,2H),8.32(d,J = 6.0Hz,4H),7.56-7.01(m,18H),6.85(br s,4H),3.89-3.74(m,2H),3.58-3.38(m,2H),3.79-3.54(m,8H),1.84-1.18(m,18H). Obtained 1 The H-NMR spectrum is shown in Figure 8.

[0168] [ka]

[0169] (Comparative Synthesis Example 1: Synthesis of Comparative Compound 1 (Comparative Squarylium Dye 1)) A comparative squarylium dye 1 was obtained in the same manner as in Synthesis Example 1 of JP 2023-006190 A. 1 The obtained comparative squarylium dye 1 was confirmed to have the following structure by H-NMR. 1 H NMR(400MHz,DMSO-d6):δ=10.30(s,1H),8.58-8.42(m,4H),7.46-6.92(m,17H ),3.36-3.04(m,2H),2.88-2.66(m,8H),2.66-3.32(m,2H),2.18-2.06(m,8H). Obtained 1 The H-NMR spectrum is shown in Figure 9.

[0170] [ka]

[0171] (Preparation Example 1: Preparation of Dispersant Solution) (1) Preparation of block copolymer A reactor equipped with a cooling tube, an addition funnel, a nitrogen inlet, a mechanical stirrer, and a digital thermometer was charged with 100 parts by mass of dehydrated tetrahydrofuran (THF) and 3.00 parts by mass of dimethylketene methyl trimethylsilyl acetal, and the atmosphere was sufficiently replaced with nitrogen. After 0.25 parts by mass of a 1M acetonitrile solution of tetrabutylammonium m-chlorobenzoate was injected with a syringe, a mixture of 50.0 parts by mass of methyl methacrylate, 30.0 parts by mass of n-butyl methacrylate, and 20.0 parts by mass of benzyl methacrylate was added dropwise over 60 minutes. The temperature was kept below 40°C by cooling the reactor in an ice bath. After 1 hour, 50.0 parts by mass of glycidyl methacrylate (GMA) was added dropwise over 30 minutes. After reacting for 1 hour, 1 part by mass of methanol was added to stop the reaction. To the obtained THF solution of the block copolymer, 450.0 parts by mass of propylene glycol methyl ether acetate (PGMEA) was added and solvent replacement was carried out by evaporation, thereby obtaining a 25.0 mass % PGMEA solution of the block copolymer. The resulting block copolymer had a mass average molecular weight (Mw) of 11,320, a number average molecular weight (Mn) of 8,950, and a molecular weight distribution (Mw / Mn) of 1.26. (2) Preparation of phosphorus-based block copolymer solution 27.80 parts by mass of PGMEA and 9.27 parts by mass of phenylphosphonic acid (PPA) were charged into a reactor equipped with a cooling tube, an addition funnel, a nitrogen inlet, a mechanical stirrer, and a digital thermometer, and the mixture was heated to a temperature of 90°C while stirring under a nitrogen stream. 100.0 parts by mass of the block copolymer were added dropwise over 30 minutes, and the mixture was heated and stirred for 2 hours to obtain a phosphorus-based block copolymer (dispersant) solution (solid content 25% by mass). The progress of the esterification reaction of GMA and PPA in the block copolymer was monitored by acid value measurement and 1 The acid value of the resulting phosphorus-based block copolymer was confirmed by H-NMR measurement, and was found to be 100 mg KOH / g.

[0172] (Preparation Example 2: Preparation of Binder Composition 1) Binder composition 1 (solid content 30% by mass) was prepared by mixing 70.0 parts by mass of PGMEA and 30.0 parts by mass of polymethyl methacrylate (Mw: 15,000, Sigma-Aldrich).

[0173] (Preparation Example 3: Preparation of Binder Composition 2) Binder composition 2 (solid content 40% by mass) was prepared by mixing 60.0 parts by mass of PGMEA, 38.40 parts by mass of a multifunctional monomer (Aronix M305, manufactured by Toagosei Co., Ltd.), and 1.60 parts by mass of a photoinitiator (Irgacure 184, manufactured by BASF Co., Ltd.).

[0174] Example 1 (1) Production of squarylium dye 1 1.00 g (0.43 mmol) of phosphomolybdic acid n-hydrate (manufactured by Nippon Inorganic Chemical Industry Co., Ltd.) was dissolved in 50 mL of methanol at 60°C, and 0.44 g (0.65 mmol) of squarylium dye 1 obtained in Synthesis Example 1 was added and stirred for 1 hour. The precipitate was collected by filtration and washed with water. The resulting precipitate was dried under reduced pressure to obtain squarylium colorant 1, which is a salt-formed compound of the squarylium dye represented by general formula (1) and a heteropolyacid (yield 95%). The resulting compound was confirmed to be the desired compound based on the following analytical results. MS(MALDI) (m / z): 675(MH + ), 1824(MH 3- ) Elemental analysis: CHN measured (85.32%, 5.90%, 8.75%); theoretical (85.41%, 5.93%, 8.67%)

[0175] (2) Manufacturing of colorant dispersion 10.00 parts by mass of squarylium colorant 1, 20.0 parts by mass of the dispersant solution of Preparation Example 1 (solid content 25.0% by mass), and 185 parts by mass of PGMEA were mixed, and the mixture was dispersed in a paint shaker (manufactured by Asada Iron Works) for 1 hour with 2 mm zirconia beads as pre-dispersion, and then for 6 hours with 0.1 mm zirconia beads as main dispersion, to obtain colorant dispersion liquid 1.

[0176] (3) Manufacturing of ink composition for heat resistance evaluation 2.85 parts by mass of the colorant dispersion 1 obtained in (2) above, 4.54 parts by mass of the binder composition 1 of Preparation Example 2, 2.73 parts by mass of PGMEA, and 0.01 parts by mass of the surfactant F-559 (manufactured by DIC) were added and mixed, and the mixture was filtered under pressure to obtain an ink composition 1-1 of Example 1.

[0177] (4) Manufacturing of ink composition for lightfastness evaluation 3.64 parts by mass of the colorant dispersion 1 obtained in (2) above, 4.32 parts by mass of the binder composition 2 of Preparation Example 3, 2.05 parts by mass of PGMEA, 0.05 parts by mass of the surfactant R08MH (manufactured by DIC), and 0.05 parts by mass of the silane coupling agent KBM503 (manufactured by Shin-Etsu Silicones) were added and mixed, and the mixture was filtered under pressure to obtain ink composition 1-2 of Example 1.

[0178] Example 2 (1) Production of squarylium dye 2 Squarylium colorant 2 was produced in the same manner as in the production of squarylium colorant 1 in Example 1, except that the squarylium dye 1 in the production of squarylium colorant 1 in Example 1 was changed to an equimolar amount of squarylium dye 2 obtained in Synthesis Example 2. The obtained squarylium colorant 2 was confirmed to be the desired compound based on the following analytical results. MS(MALDI) (m / z): 731(MH + ), 1824(MH 3- ) Elemental analysis: CHN measured (85.53%, 6.37%, 8.08%); theoretical (85.67%, 6.33%, 8.00%)

[0179] (2) Manufacturing of colorant dispersion Colorant dispersion liquid 2 was obtained in the same manner as in the production of the colorant dispersion liquid of Example 1, except that squarylium colorant 1 was changed to squarylium colorant 2 in the production of the colorant dispersion liquid of Example 1.

[0180] (3) Manufacturing of ink composition for heat resistance evaluation Ink composition 2-1 for evaluating heat resistance was obtained in the same manner as in the preparation of ink composition 1-1 for evaluating heat resistance in Example 1, except that colorant dispersion liquid 1 was changed to colorant dispersion liquid 2 in the preparation of ink composition 1-1 for evaluating heat resistance in Example 1.

[0181] (4) Manufacturing of ink composition for lightfastness evaluation Ink composition 2-2 for lightfastness evaluation was obtained in the same manner as in the preparation of ink composition 1-2 for lightfastness evaluation in Example 1, except that colorant dispersion liquid 1 was changed to colorant dispersion liquid 2 in the preparation of ink composition 1-2 for lightfastness evaluation in Example 1.

[0182] Example 3 (1) Production of squarylium dye 3 Squarylium colorant 3 was produced in the same manner as in the production of squarylium colorant 1 in Example 1, except that the squarylium dye 1 in the production of squarylium colorant 1 in Example 1 was changed to an equimolar amount of squarylium dye 3 obtained in Synthesis Example 3. The obtained squarylium colorant 3 was confirmed to be the desired compound based on the following analytical results. MS(MALDI) (m / z): 868(MH + ), 1824(MH 3- ) Elemental analysis: CHN measured (86.12%, 7.19%, 6.67%); theoretical (86.07%, 7.23%, 6.70%)

[0183] (2) Manufacturing of colorant dispersion Colorant dispersion liquid 3 was obtained in the same manner as in the production of the colorant dispersion liquid of Example 1, except that squarylium colorant 1 was changed to squarylium colorant 3 in the production of the colorant dispersion liquid of Example 1.

[0184] (3) Manufacturing of ink composition for heat resistance evaluation Ink composition 3-1 for evaluating heat resistance was obtained in the same manner as in the preparation of ink composition 1-1 for evaluating heat resistance in Example 1, except that colorant dispersion liquid 1 was changed to colorant dispersion liquid 3 in the preparation of ink composition 1-1 for evaluating heat resistance in Example 1.

[0185] (4) Manufacturing of ink composition for lightfastness evaluation Ink composition 3-2 for lightfastness evaluation was obtained in the same manner as in the preparation of ink composition 1-2 for lightfastness evaluation in Example 1, except that colorant dispersion liquid 1 was changed to colorant dispersion liquid 3 in the preparation of ink composition 1-2 for lightfastness evaluation in Example 1.

[0186] Comparative Example 1 (1) Preparation of comparative colorant solution 10.00 parts by mass of the squarylium dye 1 obtained in Synthesis Example 1 and 190 parts by mass of PGMEA were mixed and stirred for 1 hour using a magnetic stirrer to obtain a comparative colorant solution 1.

[0187] (2) Preparation of ink composition for comparative heat resistance evaluation A comparative ink composition C1-1 of Comparative Example 1 was obtained in the same manner as in Example 1(3), except that in Example 1(3), colorant dispersion liquid 1 was changed to comparative colorant solution 1.

[0188] (3) Preparation of ink composition for comparative lightfastness evaluation A comparative ink composition C1-2 of Comparative Example 1 was obtained in the same manner as in Example 1(4), except that in Example 1(4), colorant dispersion liquid 1 was changed to comparative colorant solution 1.

[0189] (Comparative Examples 2 to 4) (1) Preparation of comparative colorant solution Comparative colorant solutions 2, 3, and 4 were prepared in the same manner as in Comparative Example 1(1), except that in Comparative Example 1(1), squarylium dye 1 obtained in Synthesis Example 1 was changed to squarylium dye 2 obtained in Synthesis Example 2, squarylium dye 3 obtained in Synthesis Example 3, or comparative squarylium dye 1 obtained in Comparative Synthesis Example 1, respectively.

[0190] (2) Preparation of ink composition for comparative heat resistance evaluation Comparative ink compositions C2-1, C3-1, and C4-1 were obtained in the same manner as in Comparative Example 1(2), except that in Comparative Example 1(2), comparative colorant solution 1 was changed to comparative colorant solution 2, 3, or 4, respectively.

[0191] (3) Preparation of ink composition for comparative lightfastness evaluation Comparative ink compositions C2-2, C3-2, and C4-2 were obtained in the same manner as in Comparative Example 1(3), except that in Comparative Example 1(3), comparative colorant solution 1 was changed to comparative colorant solution 2, 3, or 4, respectively.

[0192] Comparative Example 5 (1) Preparation of Comparative Squarylium Dye 1 Comparative squarylium colorant 1, which is a salt-forming compound, was obtained in the same manner as in the production of squarylium colorant 1 in Example 1, except that the squarylium dye 1 obtained in Synthesis Example 1 in the production of squarylium colorant 1 in Example 1 was changed to comparative squarylium dye 1. The resulting compound was confirmed to be the desired compound based on the following analytical results. (Comparative squarylium color material 1) MS(MALDI) (m / z): 663(MH + ), 1824(MH 3- ) Elemental analysis: CHN measured (83.38%, 7.60%, 9.00%); theoretical (83.45%, 7.65%, 8.86%) (2) Manufacturing of colorant dispersion Comparative colorant dispersion 5 was obtained in the same manner as in the production of the colorant dispersion of Example 1, except that squarylium colorant 1 was changed to comparative squarylium colorant 1 in the production of the colorant dispersion of Example 1.

[0193] (3) Preparation of ink composition for comparative heat resistance evaluation Comparative ink composition C5-1 of Comparative Example 5 was obtained in the same manner as in Example 1(3), except that colorant dispersion 1 in Example 1(3) was changed to comparative colorant dispersion 5.

[0194] (4) Preparation of ink composition for comparative lightfastness evaluation Comparative ink composition C5-2 of Comparative Example 5 was obtained in the same manner as in Example 1(4), except that colorant dispersion 1 was changed to comparative colorant dispersion 5 in Example 1(4).

[0195] [evaluation] (1) Heat resistance (1-1) Preparation of film for heat resistance evaluation and initial spectroscopic measurement Each of the ink compositions for evaluating heat resistance obtained in the Examples and Comparative Examples was applied onto a 0.7 mm thick glass substrate (manufactured by Nippon Electric Glass, "OA-10G") using a spin coater. The substrate was then heated and dried for 3 minutes on a hot plate at 80°C to obtain a coating film. The transmission spectrum, chromaticity (x, y), luminance (Y) and L, a, b (L1, a1, b1) of the obtained coating film were measured using an Olympus "Microspectrophotometer OSP-SP200". In the measured transmission spectrum, the film thickness was adjusted so that the transmittance of the maximum absorption wavelength in the visible range (400 nm to 700 nm), that is, the minimum transmission wavelength (the wavelength at which the transmittance is at a minimum value) was 40%. (1-2) Heat resistance test The coating film obtained above was stored for 500 hours under the condition of 100° C. After the test, the transmission spectrum of the coating film was measured again. The retention rate of the maximum absorption wavelength of the coloring material or dye, that is, the transmittance value of the minimum transmission wavelength in the transmission spectrum, was calculated from the following formula (1). Transmittance retention rate = (100 - transmittance of minimum transmission wavelength after test (%)) / (100 - transmittance of minimum transmission wavelength before test (%)) x 100 ...(1)

[0196] (2) Light resistance (2-1) Preparation of film for light resistance evaluation and initial spectroscopic measurement Each ink composition for evaluating lightfastness obtained in the Examples and Comparative Examples was applied onto a 0.7 mm thick glass substrate (manufactured by Nippon Electric Glass, "OA-10G") using a spin coater. The substrate was then heated and dried on a hot plate at 80°C for 3 minutes to obtain a coating film. The obtained coating film was irradiated with 500 mJ / cm using an ultra-high pressure mercury lamp. 2 A cured film was obtained by irradiating the film with ultraviolet light of 1000 nm. The transmission spectrum, chromaticity (x, y), brightness (Y) and L, a, b (L1, a1, b1) of the obtained cured film were measured using an Olympus "Microspectrophotometer OSP-SP200". In the measured transmission spectrum, the film thickness was adjusted so that the transmittance of the maximum absorption wavelength in the visible range (400 nm to 700 nm), i.e., the minimum transmission wavelength (the wavelength at which the transmittance is the minimum value) was 40%. (2-2) Light resistance test The transmission spectrum of the cured film before the test was measured, and then the cured film was irradiated with an ultraviolet autofade meter (manufactured by Suga Test Instruments, product number: U48AU) for 100 hours at a black panel temperature of 63° C. The transmission spectrum and color coordinates (L2, a2, b2) of the cured film after light irradiation were measured again. The retention rate of the maximum absorption wavelength of the coloring material or dye, that is, the transmittance value of the minimum transmission wavelength in the transmission spectrum, was calculated from the above formula (1).

[0197] (3) Suppression of secondary absorption of colorants In the same manner as in (1-1) Preparation of a film for evaluating heat resistance and initial spectroscopic measurement, a coating film was obtained using each of the ink compositions for evaluating heat resistance obtained in the Examples and Comparative Examples. The transmission spectrum, chromaticity (x, y), luminance (Y) and L, a, b (L1, a1, b1) of the obtained coating film were measured using an Olympus "Microspectrophotometer OSP-SP200". In the measured transmission spectrum, the film thickness was adjusted so that the transmittance at the maximum absorption wavelength in the visible range (400 nm to 700 nm), i.e., the minimum transmission wavelength (the wavelength at which the transmittance is at its minimum value), was 40%, and the side absorption was evaluated using the transmittance at the wavelength of [minimum transmission wavelength (nm) - 50 nm] and the transmittance at the wavelength of [minimum transmission wavelength (nm) + 50 nm]. (Evaluation Criteria) ⊚: Both the transmittance at the wavelength of [minimum transmission wavelength (nm) - 50 nm] and the transmittance at the wavelength of [minimum transmission wavelength (nm) + 50 nm] are 70% or more. ◯: Both the transmittance at the wavelength of [minimum transmission wavelength (nm) - 50 nm] and the transmittance at the wavelength of [minimum transmission wavelength (nm) + 50 nm] are 60% or more, and at least one of them is less than 70%. ×: At least one of the transmittance at a wavelength of [minimum transmission wavelength (nm)−50 nm] and the transmittance at a wavelength of [minimum transmission wavelength (nm)+50 nm] is less than 60%.

[0198] [Table 3]

[0199] (Summary of results) It was revealed that the films of Examples 1 to 3 using squarylium dyes of the present invention in which indole is directly bonded to the squaric acid moiety and squarylium colorants 1 to 3, which are salt-forming compounds of heteropolyacids, all had excellent heat resistance and light resistance. The minimum transmission wavelengths of the films of Examples 1 to 3 using squarylium colorants 1 to 3 were 601 nm, 604 nm, and 606 nm, respectively. In particular, Example 3, in which the substituent X on the nitrogen of the indole ring in the squarylium dye represented by general formula (1) or (2) is a bulky substituent, was shown to have reduced side absorption compared to Examples 1 and 2. When a squarylium dye is used as a salt-forming compound, absorption (side absorption) is likely to occur at a wavelength different from the maximum absorption wavelength. However, when the substituent X on the indole ring is a bulky substituent, it is possible to physically separate the chromophores of the squarylium dye and suppress interactions, which is presumably why side absorption is reduced. Also, when the substituent X on the indole ring is a bulky substituent, in the squarylium dye represented by general formula (2), the chromophore plane and the phenyl-QZ 0 It is presumed that reducing the degree of freedom of the plane angle limits the range of possible ground states, thereby reducing side absorption. [Explanation of symbols]

[0200] 100 Image display device 10 Display Panel 11, 13, 17, 19 Protective film 12, 18 Polarizer 14, 16, 16' Light transparent adhesive layer 15 Display element 20 Backlight device 30 Surface functional layer 40 Display surface film (an example of an optical filter) 1 Support 2 Adhesive layer or adhesive layer 101 Squarylium dye cation 102 Colorless organic cations 103 Heteropolyacid anion 110 Salt forming compound (squarylium colorant of the present disclosure)

Claims

1. A squarylium colorant comprising a squarylium dye represented by the following general formula (1) and a salt-forming compound of a heteropolyacid: 【Chemistry 1】 (In formula (1), R １ ~R ８ each independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, -OR １０ , -OCOR １１ , -COOR １２ , -COR １３ , -NR １４ R １５ , -NHCOR １６ , -CONR １７ R １８ , -NHCONR １９ R ２０ , -NHCOOR ２１ , -SR ２２ , -SO ２ R ２３ , -SO ２ OR ２４ , -NHSO ２ R ２５ , -SO ２ N.R. ２６ R ２７ , -(R ２８ O) ｎ’ R ２９ R represents a heterocyclic group or a hydrocarbon group which may have a substituent, and adjacent substituents may be linked to each other to form a ring. １０ ~R １２ and R ２１ ~R ２５ R each independently represents a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. １３ ~R ２０ , R ２６ ~R ２７ and R ２９ R each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. ２８ each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and n′ represents an integer of 1 to 18. Each X independently represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. Each Y independently represents a divalent organic group; ０ each independently represents a group that can be derived to an organic cationic group or an organic cationic group.

2. A squarylium colorant comprising a squarylium dye represented by the following general formula (2) and a salt-forming compound of a heteropolyacid: 【Chemistry 2】 (In formula (2), R １ ~R ８ each independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, -OR １０ , -OCOR １１ , -COOR １２ , -COR １３ , -NR １４ R １５ , -NHCOR １６ , -CONR １７ R １８ , -NHCONR １９ R ２０ , -NHCOOR ２１ , -SR ２２ , -SO ２ R ２３ , -SO ２ OR ２４ , -NHSO ２ R ２５ , -SO ２ N.R. ２６ R ２７ , -(R ２８ O) ｎ’ R ２９ R represents a heterocyclic group or a hydrocarbon group which may have a substituent, and adjacent substituents may be linked to each other to form a ring. １０ ~R １２ and R ２１ ~R ２５ R each independently represents a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. １３ ~R ２０ , R ２６ ~R ２７ and R ２９ R each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent. ２８ each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and n′ represents an integer of 1 to 18. Each X independently represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. Each Q independently represents a direct bond or a divalent organic group; ０ each independently represents a group that can be derived to an organic cationic group or an organic cationic group. Each E independently represents a substituent, and adjacent substituents E may form a ring. Each of m and n independently represents an integer of 0 to 4.

3. A colorant dispersion comprising the squarylium colorant according to claim 1 or 2, a dispersant, and a solvent.

4. An ink composition comprising the squarylium colorant according to claim 1 or 2 and a binder component.

5. An optical filter comprising the squarylium color material according to claim 1 or 2.

6. A display device comprising the optical filter according to claim 5 .

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