Squarylium dye, method for purifying the same, dispersion, and near-infrared absorbing composition

Abstract

To provide a squarylium dye having excellent heat resistance, and a method for purifying the same.SOLUTION: A squarylium dye comprises at least one of a compound represented by the formula (1) in the figure and an isomer thereof, where the purity measured by high-performance liquid chromatography at a detection wavelength of 254 nm is such that the ratio of the peak area derived from the compound represented by the formula (1) and isomer thereof to the total peak area excluding peaks derived from a measurement solvent is 90% or more. Also provided are: a method for purifying the squarylium dye; and a dispersion and a near-infrared absorbing composition that comprise the squarylium dye.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to squarylium dyes, a method for purifying the same, a dispersion, and a near-infrared absorbing composition.

Background Art

[0002] Charge-coupled devices (CCDs), complementary metal-oxide semiconductor (CMOS), etc., which are solid-state imaging devices for color images, are used in video cameras, digital still cameras, mobile phones with camera functions, and the like. Since these solid-state imaging devices use silicon photodiodes having sensitivity to near-infrared light in their light-receiving portions, it is necessary to perform visual sensitivity correction, and a near-infrared absorption filter is often used. As near-infrared absorbing substances, squarylium compounds and the like are known (see, for example, Patent Document 1 or 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by an embodiment of the present invention is to provide a squarylium dye having excellent heat resistance and a method for purifying the same. Another problem to be solved by an embodiment of the present invention is to provide a dispersion and a near-infrared absorbing composition containing the above squarylium dye.

Means for Solving the Problems

[0005] Means for solving the above problems include the following aspects. <1> A squarylium dye containing at least one of the compound represented by the following formula (1) and its isomers, wherein the purity measured at a detection wavelength of 254 nm using high-performance liquid chromatography is 90% or more with respect to the peak areas of all peaks excluding the peaks derived from the measurement solvent, based on the peak areas of the compound represented by the formula (1) and its isomers.

[0006]

Chemical formula

[0007] In formula (1), R 1 and R 2 each independently represents an alkyl group, an alkenyl group, an aryl group or a heteroaryl group, R 3 and R 4 each independently represents a hydrogen atom or an alkyl group, X 1 and X 2 each independently represents an oxygen atom or -N(R 5 )-, R 5 represents a hydrogen atom, an alkyl group, an aryl group or a heteroaryl group, Y 1 ~Y 4 each independently represents a halogen atom or a monovalent organic group, and Y 1 and Y 2 , and Y 3 and Y 4 may be bonded to each other to form a ring structure, Y 1 ~Y 4 When there are a plurality of each, the plurality of Y 1 among themselves, the plurality of Y 2 among themselves, the plurality of Y 3 among themselves or the plurality of Y 4 among themselves may be bonded to each other to form a ring structure, p and s each independently represent an integer from 0 to 3, q and r each independently represent an integer from 0 to 2.

[0008] <2> R 3 and R 4 are hydrogen atoms, and X 1 and X 2 is NH as described in <1>. <3> R 1 and R 2 are the same group as described in <1> or <2>. <4> The squarylium dye according to any one of <1> to <3> which is a particle. <5> A dispersion containing the squarylium dye according to any one of <1> to <4> and a resin. <6> A near-infrared absorbing composition containing the squarylium dye according to any one of <1> to <4>. <7> A step of preparing at least one crude product of the compound represented by the above formula (1) and its isomers, a step of stirring the crude product in an organic polar solvent at 20 ° C or lower, and a step of filtering the stirred mixture after the stirring. A method for purifying the squarylium dye according to any one of <1> to <4>. <8> The method for purifying a squarylium dye according to <7>, wherein the organic polar solvent is an amide-based solvent. <9> The method for purifying a squarylium dye according to <7> or <8>, wherein the temperature of the organic polar solvent in the stirring step is 10 ° C or lower. <10> After the filtering step, mixing the filtrate with an ester-based solvent, heating the mixture to 50 ° C to the boiling point of the ester-based solvent, and filtering the heated mixture after the heating. A method for purifying a squarylium dye according to any one of <7> to <9>.

Advantages of the Invention

[0009] According to an embodiment of the present invention, a squarylium dye excellent in heat resistance and a method for purifying the same can be provided. According to another embodiment of the present invention, a dispersion and a near-infrared absorbing composition containing the above squarylium dye can be provided.

Modes for Carrying Out the Invention

[0010] Hereinafter, the content of the present disclosure will be described in detail. The description of the constituent elements described below may be based on typical embodiments of the present disclosure, but the present disclosure is not limited to such embodiments. In this specification, the symbol "~" indicating a numerical range is used to mean that the numerical values described before and after it are included as the lower limit value and the upper limit value. In the numerical ranges described step by step in this specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in other step-by-step descriptions. Also, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. Also, in the notation of a group (atomic group) in this specification, the notation that does not describe substitution and non-substitution includes both those having no substituent and those having a substituent. For example, the term "alkyl group" includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group). Also, the term "step" in this specification includes not only an independent step but also a step that cannot be clearly distinguished from other steps as long as the intended purpose of the step is achieved. Also, in the present disclosure, "mass%" and "weight%" are synonymous, and "parts by mass" and "parts by weight" are synonymous. Furthermore, in the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. In the present disclosure, the total solid content means the total mass of the components obtained by removing the solvent from the entire composition of the composition. The solid content in the present disclosure is the solid content at 25°C. Hereinafter, the present disclosure will be described in detail.

[0011] (Squarylium dye) The squarylium dye according to the present disclosure includes at least one of a compound represented by the following formula (1) and its isomers, and the purity measured at a detection wavelength of 254 nm using high performance liquid chromatography is 90% or more with respect to the peak areas of all peaks excluding the peaks derived from the measurement solvent, for the peak areas of the compound represented by the above formula (1) and its isomers.

[0012]

Chemical formula

[0013] In formula (1), R 1 and R 2 each independently represents an alkyl group, an alkenyl group, an aryl group or a heteroaryl group, R 3 and R 4 each independently represents a hydrogen atom or an alkyl group, X 1 and X 2 each independently represents an oxygen atom or -N(R 5 )-, R 5 represents a hydrogen atom, an alkyl group, an aryl group or a heteroaryl group, Y 1 ~Y 4 each independently represents a halogen atom or a monovalent organic group, and Y 1 and Y 2 , and Y 3 and Y 4 may be bonded to each other to form a ring structure, Y 1 ~Y 4 When there are a plurality of each of Y 1 among themselves, a plurality of Y 2 among themselves, a plurality of Y 3 among themselves or a plurality of Y 4 among themselves may be bonded to each other to form a ring structure, p and s each independently represent an integer from 0 to 3, q and r each independently represent an integer from 0 to 2.

[0014] In the conventional squarylium dye represented by the formula (1), impurities were contained and the heat resistance was not sufficient. The squarylium dye according to the present disclosure has a purity measured at a detection wavelength of 254 nm using high performance liquid chromatography, and the ratio of the peak areas derived from the compound represented by the above formula (1) and its isomers to all peak areas excluding the peaks derived from the measurement solvent is 90% or more. It is estimated that many impurities are removed and the heat resistance, which has been deteriorated due to impurities, is improved.

[0015] In addition, the squarylium dye according to the present disclosure is presumed to be excellent in dispersion stability and light resistance by having the above configuration.

[0016] Hereinafter, the squarylium dye according to the present disclosure will be described in detail.

[0017] <Ratio of peak area> The squarylium dye according to the present disclosure has a purity measured at a detection wavelength of 254 nm using high performance liquid chromatography, and the ratio (also referred to as "area ratio") of the peak areas derived from the compound represented by the above formula (1) and its isomers to all peak areas excluding the peaks derived from the measurement solvent is 90% or more. From the viewpoints of heat resistance, light resistance, and dispersion stability, it is preferably 91% or more, more preferably 92% or more, still more preferably 93% or more, and particularly preferably 94% or more and 100% or less.

[0018] The ratio of the peak areas derived from the compound represented by the above formula (1) and its isomers to all peak areas excluding the peaks derived from the measurement solvent, with respect to the purity measured at a detection wavelength of 254 nm using high performance liquid chromatography in the present disclosure, shall be measured by the following method. - Sample preparation method - Weigh 10 mg of the sample to be measured, make up to 20 ml with N-methylpyrrolidone (NMP), which is the measurement solvent, and dissolve it by applying ultrasonic waves for 5 minutes while keeping the liquid temperature at 10°C or lower. After filtering the dissolved solution through a syringe filter, measure it promptly by HPLC under the following measurement conditions. - HPLC Measurement Conditions - Apparatus: Nexera X2 manufactured by Shimadzu Corporation Column: Kinetex C18 2.6 μm, 150 mm × 4.6 mm Flow rate: 1.0 ml / min Column temperature: 40°C Detection wavelength: 254 nm Mobile phase: ultrapure water / tetrahydrofuran (THF) / acetic acid = 50 / 50 / 0.1 (volume %)

[0019] <Compound represented by formula (1) and its isomers> The squarylium dye according to the present disclosure may contain only the compound represented by the above formula (1), may contain its isomers, or may contain both of them. Examples of the isomers include optical isomers and the following tautomers. In addition, the squarylium structure in the compound represented by the above formula (1) exists with the charge delocalized as follows, and all represent the same compound.

[0020]

Chemical formula

[0021] R in formula (1) 1 and R 2 are each independently preferably an alkyl group or an aryl group, and more preferably an aryl group, from the viewpoints of heat resistance, light resistance, and dispersion stability. R 1 and R 2The alkyl group, alkenyl group, aryl group, and heteroaryl group in [the compound] may have substituents. Examples of the above substituents include an alkyl group, alkenyl group, aryl group, heteroaryl group, halogen atom, alkoxy group, alkoxycarbonyl group, amide group, and the like. Among them, the above substituents preferably include an alkyl group, alkoxy group, alkoxycarbonyl group, or amide group. Also, R in formula (1) 1 and R 2 are preferably the same group from the viewpoints of heat resistance, light resistance, dispersion stability, and ease of synthesis.

[0022] R 1 and R 2 The number of carbon atoms of the alkyl group represented by [R and R] (also referred to as "the number of carbon atoms") is preferably 1 to 30. The lower limit is more preferably 1 or more, and even more preferably 3 or more. The upper limit is more preferably 20 or less, and even more preferably 12 or less. The alkyl group may be linear, branched, or cyclic, but linear or branched is preferred. The number of branches of the branched alkyl group is preferably, for example, 2 to 10, and more preferably 2 to 8. If the number of branches is within the above range, the solvent solubility is good. R 1 and R 2 The number of carbon atoms of the alkenyl group represented by [R and R] is preferably 2 to 30. The lower limit is, for example, more preferably 3 or more, and even more preferably 5 or more. The upper limit is more preferably 25 or less, and even more preferably 20 or less. The alkenyl group is preferably linear or branched. The number of branches of the branched alkenyl group is preferably 2 to 10, and more preferably 2 to 8. If the number of branches is within the above range, the solvent solubility is good. R 1 and R 2 The number of carbon atoms of the aryl group represented by [R and R] is preferably 6 to 30, more preferably 6 to 20, and even more preferably 6 to 12. R 1 and R 2The heteroaryl group represented by may be monocyclic or polycyclic. The number of heteroatoms constituting the ring of the heteroaryl group is preferably 1 to 3. The heteroatoms constituting the ring of the heteroaryl group are preferably nitrogen atoms, oxygen atoms or sulfur atoms. The number of carbon atoms constituting the ring of the heteroaryl group is preferably 3 to 30, more preferably 3 to 18, and still more preferably 3 to 12.

[0023] R in formula (1) 3 and R 4 are each independently preferably a hydrogen atom, a methyl group or an ethyl group from the viewpoints of heat resistance, light resistance, and dispersion stability, more preferably a hydrogen atom or a methyl group, and particularly preferably a hydrogen atom. R in formula (1) 3 and R 4 are preferably the same group from the viewpoints of heat resistance, light resistance, dispersion stability, and ease of synthesis. R 3 and R 4 The number of carbon atoms of the alkyl group represented by is preferably 1 to 20, more preferably 1 to 10, still more preferably 1 to 4, and particularly preferably 1 or 2. The alkyl group may be linear or branched. Specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, etc. may be mentioned.

[0024] X in formula (1) 1 and X 2 are preferably -N(R 5 )- from the viewpoints of heat resistance, light resistance, dispersion stability, and ease of synthesis, and more preferably -NH-. Also, X in formula (1) 1 and X 2 are preferably the same group from the viewpoints of heat resistance, light resistance, dispersion stability, and ease of synthesis. R 5 is preferably a hydrogen atom, an alkyl group or an aryl group from the viewpoints of heat resistance, light resistance, and dispersion stability, more preferably a hydrogen atom or an alkyl group, and particularly preferably a hydrogen atom. R5 The alkyl group, aryl group, and heteroaryl group represented by may be unsubstituted or may have substituents. Examples of the substituents include an alkyl group, an alkenyl group, an aryl group, a heteroaryl group, a halogen atom, an alkoxy group, an alkoxycarbonyl group, an amide group, and the like.

[0025] Y in formula (1) 1 ~Y 4 are each independently preferably a monovalent organic group, more preferably an alkyl group, an aryl group, an alkoxy group, an alkoxycarbonyl group, or an amide group. Examples of the monovalent organic group include a cyano group, a nitro group, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an aralkyl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an alkylthio group, an arylthio group, a heteroarylthio group, -NR a1 R a2 , -COR a3 , -COOR a4 , -OCOR a5 , -NHCOR a6 , -CONR a7 R a8 , -NHCONR a9 R a10 , -NHCOOR a11 , -SO2R a12 , -SO2OR a13 , -NHSO2R a14 or -SO2NR a15 R a16 . R a1 ~R a16 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or a heteroaryl group.

[0026] Y 1 and Y 2 , and Y 3 and Y 4 may be bonded to each other to form a ring structure. For example, Y 1 and Y 2 are bonded to each other, and Y 1 and Y 2Together with the naphthalene ring directly connected thereto, it may be a tricyclic ring such as an acenaphthene ring or an acenaphthylene ring, for example. Y 1 ~Y 4 When there are a plurality of each, they may be bonded to each other to form a ring structure. For example, when 1 there are a plurality of Y 1 are bonded to each other, and Y 1 and Y 2 together with the naphthalene ring directly connected thereto, it may be a tricyclic ring such as an anthracene ring or a phenanthrene ring, for example. Note that when 1 are bonded to each other to form a ring structure, Y 1 Y which is a substituent other than 2 ~Y 4 does not necessarily have to be present in a plurality. Also, Y 2 ~Y 4 does not have to be present. The same applies when Y 2 are bonded to each other, Y 3 are bonded to each other, and Y 4 are bonded to each other to form a ring structure.

[0027] Further, in formula (1), from the viewpoints of heat resistance, light resistance, dispersion stability, and ease of synthesis, R 3 and R 4 are preferably hydrogen atoms, and X 1 and X 2 are preferably NH.

[0028] p and s are each independently preferably 0 or 1, and more preferably 0. q and r are each independently preferably 0 or 1, and more preferably 0.

[0029] Preferred specific examples of the compound represented by formula 1 are described below, but the present disclosure is not limited by these examples.

[0030]

Chemical formula

[0031] [Chemical formula]

[0032] [Chemical formula]

[0033] (In the case of) the method for producing the compound represented by formula 1 and its tautomer, there is no particular limitation, but for example, it can be synthesized by the method described in JP-A-2011-208101.

[0034] The molecular weight of the compound represented by formula (1) is preferably from 400 to 3,000, more preferably from 500 to 2,000. The compound represented by formula (1) preferably has a maximum absorption wavelength in the range of 700 nm to 1,200 nm, more preferably in the range of 750 nm to 1,000 nm. In the present disclosure, the value of the maximum absorption wavelength is obtained from the spectrum measured in the wavelength range of 350 nm to 1,200 nm using UV-1800 manufactured by Shimadzu Corporation, after dissolving the compound represented by formula (1) in chloroform to prepare a solution with a concentration of 1 g / L. The molar absorption coefficient of the compound represented by formula (1) is not limited, but is preferably from 5,000 to 250,000, more preferably from 50,000 to 200,000. The compound represented by formula (1) is preferably transparent, but may have slight coloring such as green, gray, or brown.

[0035] In addition, from the viewpoints of heat resistance and light resistance, the squarylium dye according to the present disclosure is preferably in the form of particles. The volume-average particle diameter of the squarylium dye according to the present disclosure is not particularly limited and may be appropriately selected according to the use and the like. From the viewpoints of heat resistance, light resistance, and dispersion stability, it is preferably from 10 nm to 10 μm, more preferably from 50 nm to 1 μm, still more preferably from 100 nm to 500 nm, and particularly preferably from 100 nm to 300 nm. In the present disclosure, the volume-average particle diameter of the squarylium dye is measured by preparing an aqueous dispersion of the squarylium dye and using a Zetasizer NanoZS (manufactured by Malvern Panalytical).

[0036] The squarylium dye according to the present disclosure may be a pigment or a dye, but from the viewpoints of heat resistance and light resistance, it is preferably a pigment. In the present disclosure, the pigment refers to a compound having a solubility of 0.1 g or less in 100 g of water at 25°C and a solubility of 0.1 g or less in 100 g of propylene glycol monomethyl ether acetate at 25°C.

[0037] (Purification method of squarylium dye) The purification method of the squarylium dye according to the present disclosure preferably includes a step of preparing a crude product of at least one of the compound represented by the above formula (1) and its isomers, a step of stirring the crude product in an organic polar solvent at 20°C or lower, and a step of filtering the stirred mixture after the stirring. The squarylium dye according to the present disclosure is preferably purified by the purification method of the squarylium dye according to the present disclosure.

[0038] The impurities contained in the compound represented by the above formula (1) and its isomers have low solubility and are difficult to purify. Further, it is difficult to remove the impurities incorporated inside the compound represented by the above formula (1) and its isomers. Also, the compound represented by the above formula (1) and its isomers and these impurities tend to dissolve under basic conditions, but it is known that the compound represented by the above formula (1) and its isomers are unstable under basic conditions. In the above purification method, the purity measured at a detection wavelength of 254 nm using high-performance liquid chromatography is such that the ratio of the peak areas derived from the compound represented by the above formula (1) and its isomers to the peak areas of all peaks excluding the peaks derived from the measurement solvent is 90% or more, and a squarylium dye can be easily produced. By performing the above purification method, the squarylium dye according to the present disclosure can be stably produced. In addition, the dispersion stability is improved due to the removal of impurities. Furthermore, an unexpected effect that the crystallite size increases is also observed, and the heat resistance is improved.

[0039] The above step of preparation is not particularly limited. As described above, for example, a crude product of the compound represented by the above formula (1) and its isomers can be produced by the method described in JP-A-2011-208101.

[0040] Examples of the organic polar solvent used in the above step of stirring include amide solvents such as N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, and N,N-diethylacetamide; pyrrolidone solvents such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and N-vinyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide; phenol solvents such as phenol, o-, m-, or p-cresol, xylenol, halogenated phenol, and catechol; ether solvents such as tetrahydrofuran, dioxane, and dioxolane; ketone solvents such as acetone and methyl ethyl ketone; alcohol solvents such as methanol, ethanol, and butanol; cellosolve solvents such as butyl cellosolve; pyridine, hexamethylphosphoramide, γ-butyrolactone, and the like. Among these, as the organic polar solvent, from the viewpoints of impurity removability, heat resistance, and light resistance, it is preferably at least one solvent selected from the group consisting of amide solvents, pyrrolidone solvents, sulfoxide solvents, and pyridine, more preferably an amide solvent, and particularly preferably at least one solvent selected from the group consisting of N,N-dimethylformamide and N,N-dimethylacetamide. Also, as the organic polar solvent, from the viewpoints of impurity removability, heat resistance, and light resistance, it is preferably at least one solvent selected from the group consisting of pyridine, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and dimethyl sulfoxide, and particularly preferably at least one solvent selected from the group consisting of N,N-dimethylformamide and N,N-dimethylacetamide.

[0041] The temperature of the organic polar solvent in the step of stirring is 20°C or lower, and from the viewpoints of impurity removability, heat resistance, and light resistance, it is preferably 15°C or lower, more preferably 10°C or lower, still more preferably exceeding the melting point of the organic polar solvent and 10°C or lower, particularly preferably -15°C to 10°C, and most preferably 0°C to 10°C.

[0042] The amount of the organic polar solvent used in the step of stirring is preferably 2 to 100 times the total volume of the above-mentioned crude purification product, more preferably 5 to 50 times the total volume, and particularly preferably 8 to 30 times the total volume, from the viewpoints of yield, impurity removability, heat resistance, and light resistance.

[0043] The stirring means used in the step of stirring is not particularly limited, and known stirring utensils or stirring devices can be used. In addition, the stirring vessel used in the above stirring step is not particularly limited, and known ones can be used. However, it preferably has a cooling means or a temperature adjusting means capable of adjusting the internal temperature to 15°C or lower. As the cooling means and the temperature adjusting means, known ones can be used. The stirring time used in the above stirring step is preferably 5 minutes or more, more preferably 10 minutes or more, still more preferably 20 to 600 minutes, and particularly preferably 25 to 120 minutes.

[0044] The filtering means used in the above filtering step is not particularly limited as long as the obtained squarylium dye can be filtered off, and known ones can be used. The obtained filtrate is preferably washed one or more times with a solvent in which the obtained squarylium dye has low solubility, such as an ester solvent such as ethyl acetate.

[0045] From the viewpoints of impurity removal property, heat resistance, and light resistance, the method for purifying a squarylium dye according to the present disclosure preferably includes, after the above filtering step, a step of mixing the filtrate with at least one solvent selected from the group consisting of an ester solvent, a ketone solvent, an ether solvent, and an alcohol solvent, and heating the mixture to 50°C to the boiling point of the solvent, and a step of filtering the heated mixture after the above heating. Among them, an ester solvent, a ketone solvent, or an alcohol solvent is preferable, and an ester solvent is particularly preferable. Examples of the ester solvent include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, and the like. From the viewpoints of yield, impurity removal property, heat resistance, and light resistance, the temperature in the above heating step is preferably 60°C to the boiling point of the above ester solvent. From the viewpoints of yield, impurity removal property, heat resistance, and light resistance, the amount of the ester solvent used in the above heating step is preferably 1 to 100 times the total volume of the above filtrate, more preferably 2 to 50 times the total volume, and particularly preferably 5 to 30 times the total volume.

[0046] The filtering means used in the step of filtering the heated mixture can be the same as the filtering means used in the step of filtering. Also, the obtained filtrate (also referred to as "filter cake") is preferably washed one or more times with a solvent in which the obtained squarylium dye has low solubility, such as an ester-based solvent like ethyl acetate.

[0047] Also, the method for purifying the squarylium dye according to the present disclosure preferably includes a step of drying the obtained filtrate. There is no particular limitation on the drying means in the drying step, and known drying means can be used. The drying temperature in the drying step may be a temperature at which the obtained squarylium dye does not decompose, but is preferably 10°C to 80°C, more preferably 25°C to 60°C, and particularly preferably 40°C to 60°C.

[0048] (Dispersion) The dispersion according to the present disclosure includes the squarylium dye according to the present disclosure and a resin. Examples of the resin include polymer-type dispersants described later, aqueous resins, resins used in non-aqueous vehicles, resins used in near-infrared absorbing compositions described later, and the like. The dispersion according to the present disclosure may be an aqueous dispersion or a non-aqueous dispersion. As the solvent contained in the aqueous dispersion, for example, a mixture mainly composed of water and optionally added with a hydrophilic organic solvent can be used. Examples of the hydrophilic organic solvent include alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, t-butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol; polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol; glycol derivatives such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol diacetate, ethylene glycol monomethyl ether acetate triethylene glycol monoethyl ether, ethylene glycol monophenyl ether; amines such as ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenetriamine, triethylenetetramine, polyethyleneimine, tetramethylpropylenediamine; amides such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide; and others such as dimethyl sulfoxide, sulfolane, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, acetonitrile, acetone, etc.

[0049] Furthermore, the dispersion according to the present disclosure may contain an aqueous resin as the resin. Examples of the aqueous resin include water-soluble resins that dissolve in water, water-dispersible resins that are dispersed in water, or mixtures thereof. Specific examples of the aqueous resin include resins such as acrylic, styrene-acrylic, polyester, polyamide, polyurethane, and fluorine-based resins.

[0050] The water content contained in the solvent is preferably 30% by mass to less than 100% by mass, more preferably 50% by mass to 100% by mass.

[0051] Furthermore, a surfactant and a dispersant may be used. Examples of the surfactant include anionic, nonionic, cationic, and zwitterionic surfactants, and any surfactant may be used.

[0052] Examples of the anionic surfactant include fatty acid salts, alkyl sulfate esters, alkylbenzene sulfonates, alkylnaphthalene sulfonates, dialkyl sulfosuccinates, alkyl diaryl ether disulfonates, alkyl phosphates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl aryl ether sulfates, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkyl phosphate esters, glycerol borate fatty acid esters, polyoxyethylene glycerol fatty acid esters, and the like.

[0053] Examples of the nonionic surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, polyoxyethylene oxypropylene block copolymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerol fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkyl amines, fluorine-based, silicone-based, and the like.

[0054] Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, and the like.

[0055] Examples of the amphoteric surfactant include alkyl betaine and amine oxide.

[0056] Known dispersants can be used. Examples of the dispersant include polyester-based, ε-caprolactone-based, polycarboxylate, polyphosphate, hydrostearate, amidosulfonate, polyacrylate, olefin maleate copolymer, acrylic-maleate copolymer, alkylamine acetate, organic phosphoric acids, alkyl fatty acid salts, fatty acid polyethylene glycol ester-based, silicone-based, and fluorine-based ones. Specifically, Disperbyk series (manufactured by Big Chem Japan), Solsperse series (manufactured by Zeneca), TAMN series (manufactured by Nikko Chemicals), etc. can be mentioned.

[0057] Examples of the non-aqueous dispersion include those obtained by dispersing the squarylium dye according to the present disclosure in a non-aqueous vehicle. Examples of the resin used for the non-aqueous vehicle include petroleum resin, casein, shellac, rosin-modified maleic resin, rosin-modified phenol resin, nitrocellulose, cellulose acetate butyrate, cyclized rubber, chlorinated rubber, oxidized rubber, hydrochloric rubber, phenol resin, alkyd resin, polyester resin, unsaturated polyester resin, amino resin, epoxy resin, vinyl resin, vinyl chloride, vinyl chloride-vinyl acetate copolymer, acrylic resin, methacrylic resin, polyurethane resin, silicone resin, fluorine resin, drying oil, synthetic drying oil, styrene / maleic resin, styrene / acrylic resin, polyamide resin, polyimide resin, polyester resin, benzoguanamine resin, melamine resin, urea resin, chlorinated polypropylene, butyral resin, vinylidene chloride resin, etc. As the non-aqueous vehicle, a photocurable resin or a thermosetting resin may be used.

[0058] In addition, examples of the solvent used in the non-aqueous vehicle include aromatic solvents such as toluene, xylene, and methoxybenzene; acetate solvents such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate; propionate solvents such as ethoxyethyl propionate; alcohol solvents such as methanol and ethanol; ether solvents such as butyl cellosolve, propylene glycol monomethyl ether, diethylene glycol ethyl ether, and diethylene glycol dimethyl ether; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; aliphatic hydrocarbon solvents such as hexane; nitrogen compound solvents such as N,N-dimethylformamide, γ-butyrolactam, N-methyl-2-pyrrolidone, aniline, and pyridine; lactone solvents such as γ-butyrolactone; and carbamate esters such as a 48:52 mixture of methyl carbamate and ethyl carbamate.

[0059] The content of the squarylium dye contained in the dispersion according to the present disclosure is preferably 0.1% by mass to 35% by mass, more preferably 0.5% by mass to 25% by mass, based on the total mass of the dispersion.

[0060] The dispersion according to the present disclosure may also contain various additives according to the purpose and use. For example, a surface tension adjuster, a viscosity adjuster, a specific resistance adjuster, an antifoaming agent, a fungicide, etc. can also be added.

[0061] (Near-infrared absorbing composition) The near-infrared absorbing composition according to the present disclosure contains the squarylium dye according to the present disclosure. The near-infrared absorbing composition according to the present disclosure preferably contains the squarylium dye according to the present disclosure in an amount of 0.1% by mass to 90% by mass based on the total solid content of the near-infrared absorbing composition. The lower limit is more preferably 0.5% by mass or more, still more preferably 1% by mass or more. The upper limit is more preferably 80% by mass or less, still more preferably 70% by mass or less.

[0062] <Resin> The near-infrared absorbing composition according to the present disclosure preferably contains a resin. The weight average molecular weight (Mw) of the resin is preferably from 2,000 to 2,000,000. The upper limit is more preferably 1,000,000 or less, still more preferably 500,000 or less. The lower limit is more preferably 3,000 or more, still more preferably 5,000 or more. In the case of an epoxy resin, the weight average molecular weight (Mw) of the epoxy resin is preferably 100 or more, more preferably from 200 to 2,000,000. The upper limit is still more preferably 1,000,000 or less, particularly preferably 500,000 or less. The lower limit is preferably 100 or more, more preferably 200 or more.

[0063] Examples of the resin include (meth)acrylic resin, epoxy resin, ene-thiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyethersulfone resin, polyphenylene resin, polyarylene ether phosphine oxide resin, polyimide resin, polyamideimide resin, polyolefin resin, cyclic olefin resin, and polyester resin. One of these resins may be used alone, or two or more thereof may be mixed and used. Among them, from the viewpoints of solubility and visible transparency, acrylic resin, polyester resin, or epoxy resin is preferable, and acrylic resin is more preferable.

[0064] Examples of the (meth)acrylic resin include polymers containing structural units derived from at least one of (meth)acrylic acid and its esters. Specifically, examples include polymers obtained by polymerizing at least one selected from (meth)acrylic acid, (meth)acrylic esters, (meth)acrylamide, and (meth)acrylonitrile.

[0065] Examples of the polyester resin include polymers obtained by the reaction of a polyol (e.g., ethylene glycol, propylene glycol, glycerin, trimethylolpropane) and a polybasic acid (e.g., aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, and aromatic dicarboxylic acids in which the hydrogen atoms of these aromatic nuclei are substituted with a methyl group, an ethyl group, a phenyl group, etc.), aliphatic dicarboxylic acids having 2 to 20 carbon atoms such as adipic acid, sebacic acid, dodecanedicarboxylic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid), and polymers obtained by ring-opening polymerization of cyclic ester compounds such as caprolactone monomers (e.g., polycaprolactone).

[0066] Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, aliphatic epoxy resin, etc. Examples of commercially available products include the following. Examples of the bisphenol A type epoxy resin include JER827, JER828, JER834, JER1001, JER1002, JER1003, JER1055, JER1007, JER1009, JER1010 (manufactured by Mitsubishi Chemical Corporation), EPICLON860, EPICLON1050, EPICLON1051, EPICLON1055 (manufactured by DIC Corporation), etc. Examples of the bisphenol F type epoxy resin include JER806, JER807, JER4004, JER4005, JER4007, JER4010 (manufactured by Mitsubishi Chemical Corporation), EPICLON830, EPICLON835 (manufactured by DIC Corporation), LCE-21, RE-602S (manufactured by Nippon Kayaku Co., Ltd.), etc. Examples of the phenol novolac type epoxy resin include JER152, JER154, JER157S70, JER157S65 (manufactured by Mitsubishi Chemical Corporation), EPICLON N-740, EPICLON N-770, EPICLON N-775 (manufactured by DIC Corporation), etc. Examples of cresol novolak type epoxy resins include EPICLON N-660, EPICLON N-665, EPICLON N-670, EPICLON N-673, EPICLON N-680, EPICLON N-690, EPICLON N-695 (manufactured by DIC Corporation), EOCN-1020 (manufactured by Nippon Kayaku Co., Ltd.), and the like. Examples of aliphatic epoxy resins include ADEKA RESIN EP-4080S, EP-4085S, EP-4088S (manufactured by ADEKA Corporation), Celoxide 2021P, Celoxide 2081, Celoxide 2083, Celoxide 2085, EHPE3150, EPOLEAD PB 3600, PB 4700 (manufactured by Daicel Chemical Industries, Ltd.), Denacol EX-212L, EX-214L, EX-216L, EX-321L, EX-850L (manufactured by Nagase ChemteX Corporation), and the like. Other examples include ADEKA RESIN EP-4000S, EP-4003S, EP-4010S, EP-4011S (manufactured by ADEKA Corporation), NC-2000, NC-3000, NC-7300, XD-1000, EPPN-501, EPPN-502 (manufactured by ADEKA Corporation), JER1031S (manufactured by Mitsubishi Chemical Corporation), and the like.

[0067] In addition, the resin may have a group that promotes alkali solubility (hereinafter also referred to as an acid group). Examples of the acid group include a carboxy group, a phosphoric acid group, a sulfonic acid group, a phenolic hydroxy group, and the like. These acid groups may be only one type or two or more types. Note that a resin having a group that promotes alkali solubility is also referred to as an alkali-soluble resin.

[0068] As the alkali-soluble resin, a polymer having a carboxy group in the side chain is preferable, and examples thereof include methacrylic acid copolymers, acrylic acid copolymers, itaconic acid copolymers, crotonic acid copolymers, maleic acid copolymers, partially esterified maleic acid copolymers, alkali-soluble phenol resins such as novolak-type resins, and acidic cellulose derivatives having a carboxy group in the side chain, and those obtained by adding an acid anhydride to a polymer having a hydroxy group. In particular, a copolymer of (meth)acrylic acid and another monomer copolymerizable therewith is suitable as the alkali-soluble resin. Examples of the other monomer copolymerizable with (meth)acrylic acid include alkyl (meth)acrylates, aryl (meth)acrylates, vinyl compounds, etc. Examples of the alkyl (meth)acrylate and aryl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, tolyl (meth)acrylate, naphthyl (meth)acrylate, cyclohexyl (meth)acrylate, etc. Examples of the vinyl compound include styrene, α-methylstyrene, vinyltoluene, glycidyl methacrylate, acrylonitrile, vinyl acetate, N-vinylpyrrolidone, tetrahydrofurfuryl methacrylate, polystyrene macromonomer, polymethyl methacrylate macromonomer, etc. Further, as the other monomer, N-phenylmaleimide, N-cyclohexylmaleimide, etc., which are N-substituted maleimide monomers described in JP-A-10-300922, can also be used. Note that these other monomers copolymerizable with (meth)acrylic acid may be only one kind or two or more kinds.

[0069] As the alkali-soluble resin, a copolymer of benzyl (meth) acrylate / (meth) acrylic acid, a copolymer of benzyl (meth) acrylate / (meth) acrylic acid / 2-hydroxyethyl (meth) acrylate, or a copolymer of benzyl (meth) acrylate / (meth) acrylic acid / other monomers can be preferably used. Also, those copolymerized with 2-hydroxyethyl (meth) acrylate, the 2-hydroxypropyl (meth) acrylate / polystyrene macromonomer / benzyl methacrylate / methacrylic acid copolymer described in JP-A-7-140654, the 2-hydroxy-3-phenoxypropyl acrylate / polymethyl methacrylate macromonomer / benzyl methacrylate / methacrylic acid copolymer, the 2-hydroxyethyl methacrylate / polystyrene macromonomer / methyl methacrylate / methacrylic acid copolymer, the 2-hydroxyethyl methacrylate / polystyrene macromonomer / benzyl methacrylate / methacrylic acid copolymer, etc. can also be preferably used.

[0070] It is also preferable that the alkali-soluble resin contains a polymer (a) obtained by polymerizing a monomer component containing at least one of the compound represented by the following formula (ED1) and the compound represented by the following formula (ED2) (hereinafter, these compounds may be referred to as "ether dimer").

[0071]

Chemical formula

[0072] In formula (ED1), R 1 and R 2 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 25 carbon atoms which may have a substituent.

[0073]

Chemical formula

[0074] In formula (ED2), R represents a hydrogen atom or an organic group having 1 to 30 carbon atoms. As specific examples of formula (ED2), the description in JP-A-2010-168539 can be referred to.

[0075] In formula (ED1), R 1 and R 2 The hydrocarbon group having 1 to 25 carbon atoms which may have a substituent represented by is not particularly limited. For example, linear or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, tert-amyl, stearyl, lauryl, 2-ethylhexyl; aryl groups such as phenyl; alicyclic groups such as cyclohexyl, tert-butylcyclohexyl, dicyclopentadienyl, tricyclodecanyl, isobornyl, adamantyl, 2-methyl-2-adamantyl; alkyl groups substituted with alkoxy such as 1-methoxyethyl, 1-ethoxyethyl; alkyl groups substituted with aryl groups such as benzyl; and the like. Among these, in particular, substituents on primary or secondary carbons that are difficult to eliminate by acids or heat, such as methyl, ethyl, cyclohexyl, benzyl, etc., are preferable from the viewpoint of heat resistance.

[0076] As specific examples of the ether dimer, for example, paragraph 0317 of JP-A-2013-29760 can be referred to, and this content is incorporated herein. The ether dimer may be only one kind or two or more kinds.

[0077] The alkali-soluble resin may contain a structural unit derived from a compound represented by the following formula (X).

[0078]

Chemical formula

[0079] In formula (X), R1 represents a hydrogen atom or a methyl group, R2 represents an alkylene group having 2 to 10 carbon atoms, R3 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms which may contain a benzene ring. n represents an integer of 1 to 15.

[0080] In the above formula (X), the alkylene group of R2 preferably has 2 to 3 carbon atoms. Further, the alkyl group of R3 has 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, and the alkyl group of R3 may contain a benzene ring. Examples of the alkyl group containing a benzene ring represented by R3 include a benzyl group and a 2-phenyl(isopropyl) group.

[0081] As the alkali-soluble resin, reference can be made to the descriptions in paragraphs 0558 to 0571 of JP-A-2012-208494 (corresponding to paragraphs

[0685] to

[0700] of the specification of US Patent Application Publication No. 2012 / 0235099) and paragraphs 0076 to 0099 of JP-A-2012-198408, and these contents are incorporated herein.

[0082] The acid value of the alkali-soluble resin is preferably 30 mgKOH / g to 200 mgKOH / g. The lower limit is more preferably 50 mgKOH / g or more, and even more preferably 70 mgKOH / g or more. The upper limit is more preferably 150 mgKOH / g or less, and even more preferably 120 mgKOH / g or less.

[0083] Further, the resin may have a polymerizable group. By having a polymerizable group in the resin, a hard film can be formed without using a curable compound described later. Examples of the polymerizable group include a (meth)allyl group and a (meth)acryloyl group. Examples of the resin containing a polymerizable group include Diana-NR series (manufactured by Mitsubishi Rayon Co., Ltd.), Photomer6173 (COOH-containing polyurethane acrylate oligomer, manufactured by Diamond Shamrock Co., Ltd.), Biscoat R-264, KS Resist 106 (all manufactured by Osaka Organic Chemical Industry Co., Ltd.), Cyclomer P series (for example, ACA230AA), Placcel CF200 series (all manufactured by Daicel Chemical Industries, Ltd.), Ebecryl3800 (manufactured by Daicel UCB Co., Ltd.), and Acry Cure RD-F8 (manufactured by Nippon Shokubai Co., Ltd.). Further, the above-described epoxy resins and the like are also included.

[0084] In the near-infrared absorbing composition according to the present disclosure, the resin content is preferably 1% by mass to 80% by mass based on the total solid content of the near-infrared absorbing composition. The lower limit is more preferably 5% by mass or more, and even more preferably 7% by mass or more. The upper limit is more preferably 50% by mass or less, and even more preferably 30% by mass or less.

[0085] <<Curable compound>> The near-infrared absorbing composition according to the present disclosure may contain a curable compound. As the curable compound, a compound having a polymerizable group (hereinafter sometimes referred to as a "polymerizable compound") is preferable. Examples of the polymerizable compound include compounds containing a group having an ethylenically unsaturated bond, a cyclic ether (epoxy, oxetane) group, a methylol group, etc., and compounds containing a group having an ethylenically unsaturated bond are preferable. Examples of the group having an ethylenically unsaturated bond include a vinyl group, a (meth)allyl group, a (meth)acryloyl group, etc. The polymerizable compound may be monofunctional or polyfunctional, but is preferably polyfunctional. By including a polyfunctional polymerizable compound, the near-infrared shielding property and heat resistance can be further improved. The number of functional groups is not particularly limited, but 2 to 8 functional groups are preferable, and 3 to 6 functional groups are more preferable. The polymerizable compound may be in any chemical form such as, for example, a monomer, a prepolymer, an oligomer, and a mixture thereof, and a multimer thereof. As the polymerizable compound, a monomer is preferable. The polymerizable compound is preferably a (meth)acrylate compound having 3 to 15 functional groups, and more preferably a (meth)acrylate compound having 3 to 6 functional groups.

[0086] The curable compound is preferably a compound containing a group having an ethylenically unsaturated bond. As an example of the compound containing a group having an ethylenically unsaturated bond, the descriptions in paragraphs 0033 to 0034 of JP 2013-253224 A can be referred to, and this content is incorporated herein. Specific examples include ethylene oxide-modified pentaerythritol tetraacrylate (commercially available as NK Ester ATM-35E; manufactured by Shin-Nakamura Chemical Co., Ltd.), dipentaerythritol triacrylate (commercially available as KAYARAD D-330; manufactured by Nippon Kayaku Co., Ltd.), dipentaerythritol tetraacrylate (commercially available as KAYARAD D-320; manufactured by Nippon Kayaku Co., Ltd.), dipentaerythritol penta(meth)acrylate (commercially available as KAYARAD D-310; manufactured by Nippon Kayaku Co., Ltd.), dipentaerythritol hexa(meth)acrylate (commercially available as KAYARAD DPHA; manufactured by Nippon Kayaku Co., Ltd., A-DPH-12E; manufactured by Shin-Nakamura Chemical Co., Ltd.), and compounds containing a structure in which these (meth)acryloyl groups are bonded via ethylene glycol or propylene glycol residues are preferred. These oligomer types can also be used. In addition, the descriptions of the polymerizable compounds in paragraphs 0034 to 0038 of JP-A-2013-253224 can be referred to, and this content is incorporated herein. In addition, polymerizable monomers and the like described in paragraph 0477 of JP-A-2012-208494 (

[0585] in the specification of corresponding US Patent Application Publication No. 2012 / 0235099) are cited as specific examples, and these contents are incorporated herein. As the compound containing a group having an ethylenically unsaturated bond, diglycerin EO (ethylene oxide) -modified (meth)acrylate (commercially available as M-460; manufactured by Toagosei Co., Ltd.) is preferred. Pentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-TMMT), 1,6-hexanediol diacrylate (manufactured by Nippon Kayaku Co., Ltd., KAYARAD HDDA) are also preferred. These oligomer types can also be used. For example, RP-1040 (manufactured by Nippon Kayaku Co., Ltd.) and the like can be mentioned.

[0087] The compound containing a group having an ethylenically unsaturated bond may further have an acid group such as a carboxy group, a sulfonic acid group, or a phosphoric acid group. Examples of the compound having an acid group include esters of an aliphatic polyhydroxy compound and an unsaturated carboxylic acid. A polyfunctional monomer having an acid group formed by reacting an unreacted hydroxy group of an aliphatic polyhydroxy compound with a non-aromatic carboxylic anhydride is preferred. Particularly preferred is a compound in which the aliphatic polyhydroxy compound is at least one of pentaerythritol and dipentaerythritol. Commercially available products include, for example, M-305, M-510, M-520, etc. of the Aronix series, which are polybasic acid-modified acrylic oligomers manufactured by Toagosei Co., Ltd. The acid value of the compound having an acid group is preferably 0.1 to 40 mgKOH / g. The lower limit is more preferably 5 mgKOH / g or more. The upper limit is more preferably 30 mgKOH / g or less.

[0088] The curable compound is also a preferred embodiment in a compound having a caprolactone structure. As the compound having a caprolactone structure, the descriptions in paragraphs 0042 to 0045 of JP-A-2013-253224 can be referred to, and this content is incorporated herein. Commercially available products include, for example, SR-494, a tetrafunctional acrylate having 4 ethyleneoxy chains manufactured by Sartomer Co., Ltd., DPCA-60, a hexafunctional acrylate having 6 pentyleneoxy chains manufactured by Nippon Kayaku Co., Ltd., TPA-330, a trifunctional acrylate having 3 isobutyleneoxy chains, and the like.

[0089] When the near-infrared absorbing composition according to the present disclosure contains a curable compound, the content of the curable compound is preferably 1% by mass to 90% by mass based on the total solid content of the near-infrared absorbing composition. The lower limit is more preferably 15% by mass or more, and even more preferably 40% by mass or more. The upper limit is more preferably 80% by mass or less, and even more preferably 75% by mass or less. The curable compound may be only one type or two or more types. In the case of two or more types, the total amount is preferably within the above range.

[0090] <<Photoinitiator>> The near-infrared absorbing composition according to the present disclosure may contain a photoinitiator. The content of the photoinitiator is preferably 0.01% by mass to 30% by mass based on the total solid content of the near-infrared absorbing composition. The lower limit is more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more. The upper limit is more preferably 20% by mass or less, and even more preferably 15% by mass or less. The photoinitiator may be only one type or two or more types. In the case of two or more types, the total amount is preferably within the above range. The photoinitiator is not particularly limited as long as it has the ability to initiate the polymerization of the curable compound by light, and can be appropriately selected according to the purpose. Among them, those having photosensitivity to light rays in the ultraviolet region to the visible region are preferred.

[0091] The photoinitiator is preferably a compound having an aromatic group. For example, acylphosphine compounds, acetophenone-based compounds, α-aminoketone compounds, benzophenone-based compounds, benzoin ether-based compounds, ketal derivative compounds, thioxanthone compounds, oxime compounds, hexaarylbiimidazole compounds, trihalomethyl compounds, azo compounds, organic peroxides, diazonium compounds, iodonium compounds, sulfonium compounds, azinium compounds, benzoin ether-based compounds, ketal derivative compounds, onium salt compounds such as metallocene compounds, organic boron salt compounds, disulfone compounds, thiol compounds, etc. may be mentioned. Regarding the photoinitiator, the descriptions in paragraphs 0217 to 0228 of JP-A No. 2013-253224 can be referred to, and this content is incorporated herein. As the oxime compound, commercially available products such as IRGACURE-OXE01 and IRGACURE-OXE02 (both manufactured by BASF), TR-PBG-304 (manufactured by Changzhou Qiangli Electronic New Materials Co., Ltd.), Adeka Arcles NCI-831, and Adeka Arcles NCI-930 (both manufactured by ADEKA) can be used. As acetophenone compounds, commercially available IRGACURE-907, IRGACURE-369, and IRGACURE-379 (all manufactured by BASF) can be used. As acylphosphine compounds, commercially available IRGACURE-819 and DAROCUR-TPO (both manufactured by BASF) can be used. In the present invention, an oxime compound having a fluorine atom can also be used as a photopolymerization initiator. Specific examples of the oxime compound having a fluorine atom include the compounds described in JP-A-2010-262028, compounds 24, 36 to 40 described in JP-T-2014-500852, and compound (C-3) described in JP-A-2013-164471. This content is incorporated herein.

[0092] <<Solvent>> The near-infrared absorbing composition according to the present disclosure may contain a solvent. The solvent is not particularly limited, and can be appropriately selected according to the purpose as long as it can uniformly dissolve or disperse each component of the near-infrared absorbing composition according to the present disclosure. For example, water or an organic solvent can be used, and an organic solvent is preferred. Examples of the organic solvent include alcohols (e.g., methanol), ketones, esters, aromatic hydrocarbons, halogenated hydrocarbons, and dimethylformamide, dimethylacetamide, dimethyl sulfoxide, sulfolane, etc. These may be used alone or in combination of two or more. When two or more solvents are used in combination, a mixed solution composed of two or more selected from methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl cellosolve acetate, ethyl lactate, diethylene glycol dimethyl ether, butyl acetate, methyl 3-methoxypropionate, 2-heptanone, cyclohexanone, ethyl carbitol acetate, butyl carbitol acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate is preferred. Specific examples of alcohols, aromatic hydrocarbons, and halogenated hydrocarbons include those described in Paragraph 0136 of JP-A-2012-194534, the content of which is incorporated herein. Specific examples of esters, ketones, and ethers include those described in Paragraph 0497 of JP-A-2012-208494 (

[0609] of the corresponding US Patent Application Publication No. 2012 / 0235099), and further include n-amyl acetate, ethyl propionate, dimethyl phthalate, ethyl benzoate, methyl sulfate, acetone, methyl isobutyl ketone, diethyl ether, ethylene glycol monobutyl ether acetate, and the like. The amount of the solvent in the near-infrared absorbing composition according to the present disclosure is preferably an amount such that the solid content of the squarylium dye according to the present disclosure is 10% by mass to 90% by mass. The lower limit is more preferably 20% by mass or more. The upper limit is more preferably 80% by mass or less.

[0093] <<Surfactant>> The near-infrared absorbing composition according to the present disclosure may contain a surfactant. Only one type of surfactant may be used, or two or more types may be combined. The content of the surfactant is preferably 0.0001 to 5% by mass based on the total solid content of the near-infrared absorbing composition according to the present disclosure. The lower limit is more preferably 0.005% by mass or more, and even more preferably 0.01% by mass or more. The upper limit is more preferably 2% by mass or less, and even more preferably 1% by mass or less. As the surfactant, various surfactants such as fluorosurfactants, nonionic surfactants, cationic surfactants, anionic surfactants, and silicone surfactants can be used. The near-infrared absorbing composition according to the present disclosure preferably contains at least one of a fluorosurfactant and a silicone surfactant. The surfactant reduces the interfacial tension between the surface to be coated and the coating liquid, improving the wettability of the surface to be coated. For this reason, the liquid characteristics (particularly, fluidity) of the composition are improved, and the uniformity of the coating thickness and the liquid-saving property are further improved. As a result, even when a thin film of about several μm is formed with a small amount of liquid, a film with a uniform thickness and small thickness unevenness can be formed.

[0094] The fluorine content of the fluorosurfactant is preferably 3 to 40% by mass. The lower limit is more preferably 5% by mass or more, and even more preferably 7% by mass or more. The upper limit is more preferably 30% by mass or less, and even more preferably 25% by mass or less. When the fluorine content is within the above-described range, it is effective in terms of the uniformity of the coating film thickness and liquid-saving property, and the solubility is also good. Specific examples of the fluorosurfactant include the surfactants described in paragraphs 0060 to 0064 of JP-A-2014-41318 (corresponding to paragraphs 0060 to 0064 of the pamphlet of International Publication WO2014 / 17669), and the contents thereof are incorporated herein. Commercially available products of fluorosurfactants include, for example, Megafac F-171, F-172, F-173, F-176, F-177, F-141, F-142, F-143, F-144, R30, F-437, F-475, F-479, F-482, F-554, F-780 (above, manufactured by DIC Corporation), Fluorad FC430, FC431, FC171 (above, manufactured by Sumitomo 3M Limited), Surflon S-382, SC-101, SC-103, SC-104, SC-105, SC-1068, SC-381, SC-383, S-393, KH-40 (above, manufactured by Asahi Glass Co., Ltd.), and the like. Also, the following compounds are exemplified as the fluorosurfactants used in the present invention.

[0095]

Chemical formula

[0096] The weight average molecular weight of the above compounds is, for example, 14,000. Specific examples of the nonionic surfactant include the nonionic surfactants described in paragraph 0553 of JP-A-2012-208494 (

[0679] of the specification of US Patent Application Publication No. 2012 / 0235099 corresponding thereto), and the contents thereof are incorporated herein. Specific examples of the cationic surfactant include those described in paragraph 0554 of JP-A-2012-208494 (paragraph

[0680] of the specification of US Patent Application Publication No. 2012 / 0235099 corresponding thereto), and the contents thereof are incorporated herein. Specific examples of the anionic surfactant include W004, W005, W017 (manufactured by Yusho Co., Ltd.), and the like. Examples of the silicone surfactant include those described in paragraph 0556 of JP-A-2012-208494 (paragraph

[0682] of the specification of US Patent Application Publication No. 2012 / 0235099 corresponding thereto), and the contents thereof are incorporated herein.

[0097] <<Polymerization inhibitor>> The near-infrared absorbing composition according to the present disclosure may contain a small amount of a polymerization inhibitor in order to prevent unnecessary reactions of the curable compound during production or storage. Examples of the polymerization inhibitor include hydroquinone, paramethoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis(3-methyl-6-t-butylphenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), N-nitrosophenylhydroxylamine cerium(I) salt, and the like, and paramethoxyphenol is preferred. When the near-infrared absorbing composition according to the present disclosure contains a polymerization inhibitor, the content of the polymerization inhibitor is preferably 0.01% by mass to 5% by mass based on the total solid content of the near-infrared absorbing composition according to the present disclosure.

[0098] <<Ultraviolet absorber>> The near-infrared absorbing composition according to the present disclosure may contain an ultraviolet absorber. As the ultraviolet absorber, the compounds described in paragraphs 0137 to 0142 of JP-A-2012-068418 (corresponding to paragraphs 0251 to 0254 of the specification of US Patent Application Publication No. 2012 / 0068292) and the compounds described in Patent No. 7330295 can be used, and the contents thereof can be incorporated herein by reference and incorporated into this specification. Examples of commercially available products include UV503 (Daito Chemical Co., Ltd.). The near-infrared absorbing composition according to the present disclosure may or may not contain an ultraviolet absorber. When it contains an ultraviolet absorber, the content of the ultraviolet absorber is preferably 0.01% by mass to 10% by mass, more preferably 0.01% by mass to 5% by mass, based on the total solid content of the composition. In the present disclosure, one type of ultraviolet absorber may be used alone, or two or more types may be used in combination.

[0099] <<Other near-infrared absorbing substances>> The near-infrared absorbing composition according to the present disclosure may further contain a near-infrared absorbing substance (hereinafter also referred to as other near-infrared absorbing substances) having a maximum absorption wavelength in the near-infrared region different from the maximum absorption wavelength of the squarylium dye according to the present disclosure. According to this aspect, a near-infrared cut filter capable of absorbing light in a wider wavelength region of the near-infrared region than only the squarylium dye according to the present disclosure can be obtained. Examples of other near-infrared absorbing substances include copper compounds, cyanine compounds, phthalocyanine compounds, iminium compounds, thiol complex compounds, transition metal oxide compounds, squarylium compounds other than the squarylium dye according to the present disclosure, naphthalocyanine compounds, quaterrylene compounds, dithiol metal complex compounds, croconium compounds, and the like. As the phthalocyanine compound, naphthalocyanine compound, iminium compound, cyanine compound, squarylium compound, and croconium compound, the compounds described in paragraphs 0010 to 0081 of JP-A-2010-111750 may be used, and this content is incorporated herein. Regarding the cyanine compound, for example, "Functional Dyes, Nobuaki Ohkawa / Ken Matsuoka / Tetsujiro Kitao / Tsuneaki Hirashima, published by Kodansha Scientific" can be referred to, and this content is incorporated herein. As the copper compound, the copper compounds described in paragraphs 0013 to 0056 of JP-A-2014-41318 and paragraphs 0012 to 0030 of JP-A-2014-32380 may be used, and this content is incorporated herein. In addition, the compounds disclosed in paragraphs 0004 to 0016 of JP-A-07-164729, the compounds disclosed in paragraphs 0027 to 0062 of JP-A-2002-146254, and the crystallites of oxides containing at least one of Cu and P disclosed in paragraphs 0034 to 0067 of JP-A-2011-164583 and having a number average aggregate particle diameter of 5 to 200 nm may be used as the near-infrared absorbing particles, and this content is incorporated herein. As commercially available products, "IRA842" manufactured by Exiton, "FD-25" manufactured by Yamada Chemical, etc. can also be used. When containing other near-infrared absorbing substances, the content of the other near-infrared absorbing substances is preferably 0.01% by mass to 50% by mass, more preferably 0.01 to 45% by mass, based on the total solid content of the composition of the present invention. In the present disclosure, the other near-infrared absorbing substances may be used alone or in combination of two or more.

[0100] <<Other Components>> Examples of other components that can be used in combination with the near-infrared absorbing composition according to the present disclosure include a sensitizer, a crosslinking agent, a curing accelerator, a filler, a heat curing accelerator, a thermal polymerization inhibitor, a plasticizer, etc. Further, an adhesion promoter to the substrate surface and other auxiliaries (for example, conductive particles, fillers, defoaming agents, flame retardants, leveling agents, peeling accelerators, antioxidants, fragrances, surface tension regulators, chain transfer agents, etc.) may be used in combination. By appropriately containing these components, properties such as the stability and film physical properties of the target near-infrared cut filter can be adjusted. These components can refer to the descriptions in, for example, paragraphs 0183 to 0228 of JP-A-2012-003225 (corresponding to

[0237] to

[0309] of the specification of US Patent Application Publication No. 2013 / 0034812), paragraphs 0101 to 0104, paragraphs 0107 to 0109 of JP-A-2008-250074, paragraphs 0159 to 0184 of JP-A-2013-195480, etc. These contents are incorporated herein.

[0101] <Preparation of Composition> The near-infrared absorbing composition according to the present disclosure can be prepared by mixing the above components. When preparing the composition, each component constituting the composition may be batch-blended, or each component may be dissolved or dispersed in an organic solvent and then sequentially blended. Also, the charging order and working conditions during blending are not particularly restricted. In the present disclosure, for the purposes of removing foreign substances and reducing defects, etc., it is preferable to filter the composition with a filter. As the filter, any filter that has been conventionally used for filtration purposes, etc., can be used without particular limitation. For example, filters composed of fluororesins such as polytetrafluoroethylene (PTFE), polyamide resins such as nylon-6 and nylon-6,6, polyolefin resins such as polyethylene and polypropylene (PP) (including high density and ultra-high molecular weight), etc., can be mentioned. Among these materials, polypropylene (including high density polypropylene) and nylon are preferable. The pore diameter of the filter is preferably 0.1 μm to 7.0 μm, more preferably 0.2 μm to 2.5 μm, still more preferably 0.2 μm to 1.5 μm, and particularly preferably 0.3 μm to 0.7 μm. By setting it within this range, it is possible to surely remove fine foreign substances such as impurities and aggregates contained in the composition while suppressing filter clogging. When using filters, different filters may be combined. In that case, the filtering with the first filter may be performed only once or may be performed two or more times. When performing filtering two or more times by combining different filters, it is preferable that the pore diameter of the subsequent filtering is the same as or larger than that of the first filtering. Also, the first filters with different pore diameters may be combined within the above-described range. The pore diameter here can refer to the nominal value of the filter manufacturer. As commercially available filters, for example, various filters provided by Nippon Pall Corporation, Advantec Toyo Co., Ltd., Nippon Integris Co., Ltd. (former Nippon Microlith Co., Ltd.) or Kits Microfilter Co., Ltd. can be selected. As the second filter, one formed of the same material as the above-described first filter can be used. The pore diameter of the second filter is preferably 0.2 to 10.0 μm, more preferably 0.2 to 7.0 μm, and still more preferably 0.3 to 6.0 μm. By setting it within this range, foreign matters can be removed while leaving the component particles contained in the composition.

[0102] The viscosity of the near-infrared absorbing composition according to the present disclosure is preferably in the range of 1 to 3000 mPa·s, for example, when forming a near-infrared cut filter by coating. The lower limit is more preferably 10 mPa·s or more, and still more preferably 100 mPa·s or more. The upper limit is more preferably 2000 mPa·s or less, and still more preferably 1500 mPa·s or less. The near-infrared absorbing composition according to the present disclosure can also be used for a near-infrared cut filter on the light-receiving side of a solid-state imaging device (for example, a near-infrared cut filter for a wafer-level lens), a near-infrared cut filter on the back side (opposite to the light-receiving side) of the solid-state imaging device, etc. Further, the near-infrared absorbing composition according to the present disclosure may be directly applied onto an image sensor to form a coating film for use. Since the near-infrared absorbing composition according to the present disclosure can be supplied in a coatable state, a near-infrared cut filter can be easily formed on a desired member or position of a solid-state imaging device.

[0103] <Use of Near-Infrared Absorbing Composition> The near-infrared absorbing composition according to the present disclosure can be used, for example, in (i) a near-infrared cut filter application capable of absorbing light in a specific near-infrared region, (ii) a near-infrared cut filter application capable of absorbing light in a wider wavelength range of the near-infrared region than only the squarylium dye according to the present disclosure, and the like. When used in the near-infrared cut filter application of (i) above, the near-infrared absorbing composition according to the present disclosure contains the squarylium dye according to the present disclosure and preferably does not substantially contain a near-infrared absorbing substance having a maximum absorption wavelength in a near-infrared region different from the maximum absorption wavelength of the squarylium dye according to the present disclosure. Here, "not substantially containing" means that the content is 1% by mass or less of the squarylium dye according to the present disclosure. When used in the near-infrared cut filter application of (ii) above, the near-infrared absorbing composition according to the present disclosure preferably contains, in addition to the squarylium dye according to the present disclosure, an infrared absorbing substance having a maximum absorption wavelength in a near-infrared region different from the maximum absorption wavelength of the squarylium dye according to the present disclosure.

[0104] <Hardened Film, Near-Infrared Cut Filter> The hardened film according to the present disclosure and the near-infrared cut filter according to the present disclosure are made using the above-described near-infrared absorbing composition according to the present disclosure. The near-infrared cut filter according to the present disclosure preferably satisfies at least one of the following conditions (1) to (4) for the light transmittance, and more preferably satisfies all of the conditions (1) to (4). (1) The light transmittance at a wavelength of 400 nm is preferably 70% or more, more preferably 80% or more, still more preferably 85% or more, and particularly preferably 90% or more. (2) The light transmittance at a wavelength of 500 nm is preferably 70% or more, more preferably 80% or more, still more preferably 90% or more, and particularly preferably 95% or more. (3) The light transmittance at a wavelength of 600 nm is preferably 70% or more, more preferably 80% or more, still more preferably 90% or more, and particularly preferably 95% or more. (4) The light transmittance at a wavelength of 650 nm is preferably 70% or more, more preferably 80% or more, still more preferably 90% or more, and particularly preferably 95% or more.

[0105] The film thickness of the near-infrared cut filter according to the present disclosure can be appropriately selected according to the purpose. The film thickness is preferably 300 μm or less, more preferably 200 μm or less, and still more preferably 100 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 still more preferably 0.3 μm or more. The near-infrared cut filter according to the present disclosure preferably has a film thickness of 200 μm or less and a light transmittance of 70% or more, more preferably 80% or more, and still more preferably 90% or more in the entire range of wavelengths from 400 to 650 nm. Also, the light transmittance at at least one point in the range of wavelengths from 750 to 830 nm is preferably 20% or less, and more preferably 10% or less.

[0106] <Use of the near-infrared cut filter> The near-infrared cut filter according to the present disclosure is used for lenses having a function of absorbing and cutting near-infrared rays (camera lenses for cameras such as digital cameras, mobile phones, and in-vehicle cameras, f-θ lenses, optical lenses such as pickup lenses), optical filters for semiconductor light-receiving elements, near-infrared absorption films and near-infrared absorption plates for blocking heat rays for energy saving, agricultural coating agents for selective utilization of sunlight, recording media using the absorption heat of near-infrared rays, near-infrared cut filters for electronic devices and photography, protective glasses, sunglasses, heat ray shielding films, optical character reading and recording, prevention of copying of confidential documents, electrophotographic photoreceptors, laser welding, etc. It is also useful as a noise cut filter for CCD cameras and a filter for CMOS image sensors.

[0107] <Manufacturing method of the cured film and the near-infrared cut filter> The cured film according to the present disclosure and the near-infrared cut filter according to the present disclosure are obtained using the near-infrared absorbing composition according to the present disclosure. Specifically, it can be manufactured through a process of forming a film by applying the near-infrared absorbing composition according to the present disclosure to a support, and a process of drying the film. The film thickness, laminated structure, etc. can be appropriately selected according to the purpose. Further, a process of forming a pattern may be performed.

[0108] The process of forming a film can be carried out, for example, by dropping the near-infrared absorbing composition according to the present disclosure onto a support using a drop casting method, a spin coater, a slit spin coater, a slit coater, screen printing, an applicator coating, etc. In the case of the drop casting method, it is preferable to form a dropping region of the composition with a photoresist as a partition wall on the support so that a uniform film can be obtained with a predetermined film thickness. The support may be a transparent substrate made of glass or the like. It may also be a solid-state imaging device. It may also be another substrate provided on the light-receiving side of the solid-state imaging device. It may also be a layer such as a planarization layer provided on the light-receiving side of the solid-state imaging device. In the process of drying the film, the drying conditions vary depending on each component, the type of solvent, the usage ratio, etc., but are about 30 seconds to 15 minutes at a temperature of 60°C to 150°C. Examples of the process of forming a pattern include a method that includes a process of applying the near-infrared absorbing composition according to the present disclosure onto a support to form a film-like composition layer, a process of exposing the composition layer in a pattern, and a process of developing and removing the unexposed portion to form a pattern. As the process of forming a pattern, a pattern may be formed by a photolithography method or a dry etching method. The manufacturing method of the near-infrared cut filter may include other processes. There are no particular restrictions on the other processes, and they can be appropriately selected according to the purpose. For example, a surface treatment process of the base material, a preheating process (pre-bake process), a curing process, a post-heating process (post-bake process), etc. can be mentioned.

[0109] <<Pre-heating process and post-heating process>> The heating temperature in the pre-heating process and the post-heating process is preferably 80 to 200 °C. The upper limit is more preferably 150 °C or less. The lower limit is more preferably 90 °C or more. The heating time in the pre-heating process and the post-heating process is preferably 30 to 240 seconds. The upper limit is more preferably 180 seconds or less. The lower limit is more preferably 60 seconds or more.

[0110] <<Hardening treatment process>> The hardening treatment process is a process of performing a hardening treatment on the formed film as necessary. By performing this treatment, the mechanical strength of the near-infrared cut filter is improved. The above hardening treatment process is not particularly limited and can be appropriately selected according to the purpose. For example, full-surface exposure treatment, full-surface heat treatment, etc. are preferably cited. In the present invention, "exposure" is used in the sense of including not only irradiation with light of various wavelengths but also irradiation with radiation such as electron beams and X-rays. Exposure is preferably performed by irradiation with radiation. As the radiation that can be used for exposure, in particular, electron beams, ultraviolet rays such as KrF, ArF, g-line, h-line, i-line, and visible light are preferably used. Examples of the exposure method include stepper exposure and exposure using a high-pressure mercury lamp. The exposure dose is preferably 5 mJ / cm 2 ~3,000 mJ / cm 2 The upper limit is more preferably 2,000 mJ / cm 2 or less, and even more preferably 1,000 mJ / cm 2 or less. The lower limit is more preferably 10 mJ / cm 2 or more, and even more preferably 50 mJ / cm 2 or more. Examples of the method of full-surface exposure treatment include, for example, a method of exposing the entire surface of the formed film. When the near-infrared absorbing composition according to the present disclosure contains a polymerizable compound, full-surface exposure promotes the hardening of the polymer components in the film, further progresses the hardening of the film, and improves the mechanical strength and durability. The apparatus for performing full-surface exposure is not particularly limited and can be appropriately selected according to the purpose. For example, an ultraviolet (UV) exposure machine such as an ultra-high pressure mercury lamp is preferably mentioned. As a method of full-surface heat treatment, a method of heating the entire surface of the formed film is mentioned. By full-surface heating, the film strength of the pattern can be increased. The heating temperature in full-surface heating is preferably 100 to 260°C. The lower limit is more preferably 120°C or higher, and even more preferably 160°C or higher. The upper limit is more preferably 240°C or lower, and even more preferably 220°C or lower. If the heating temperature is within the above range, a film with excellent strength can be easily obtained. The heating time in full-surface heating is preferably 1 to 180 minutes. The lower limit is more preferably 3 minutes or longer, and even more preferably 5 minutes or longer. The upper limit is more preferably 120 minutes or shorter. The apparatus for performing full-surface heating is not particularly limited and can be appropriately selected from known apparatuses according to the purpose. For example, a dry oven, a hot plate, an infrared heater, etc. are mentioned.

[0111] <Solid-state imaging device, infrared sensor> The solid-state imaging device according to the present disclosure includes a cured film formed using the near-infrared absorbing composition according to the present disclosure. Further, the infrared sensor according to the present disclosure includes a cured film formed using the near-infrared absorbing composition according to the present disclosure. As an embodiment of the infrared sensor according to the present disclosure, an imaging region provided on a solid-state imaging device may have a near-infrared cut filter and a color filter. The near-infrared cut filter can be formed, for example, using the near-infrared absorbing composition according to the present disclosure. In addition, as the solid-state imaging device and the infrared sensor according to the present disclosure, for example, reference can be made to the solid-state imaging device and the infrared sensor described in International Publication No. 2016 / 136783. Further, as the infrared sensor according to the present disclosure, for example, in an imaging device, it can be used for a motion sensor, a proximity sensor, a gesture sensor, etc. Furthermore, the imaging device can incorporate a camera module having a solid-state imaging device and the above-described near-infrared cut filter.

[0112] <Other coloring compounds> The dispersion according to the present disclosure and the near-infrared absorbing composition according to the present disclosure may contain other coloring compounds (pigments, dyes, etc.) other than the squarylium dye according to the present disclosure. The other coloring compounds may be dyes or pigments. The pigment may be contained as a solid particle dispersion such as a pigment dispersion. Also, it may be an existing dye or a newly synthesized dye.

[0113] Examples of the dye include anthraquinone-based (e.g., anthraquinone compounds described in JP-A-2001-108815), phthalocyanine-based (e.g., phthalocyanine compounds described in US Patent Application Publication No. 2008 / 0076044), xanthene-based (e.g., C.I. Acid Red 289), triarylmethane-based (e.g., C.I. Acid Blue 7, C.I. Acid Blue 83, C.I. Acid Blue 90, C.I. Solvent Blue 38, C.I. Acid Violet 17, C.I. Acid Violet 49, C.I. Acid Green 3, squarylium-based, pyrazole azo-based, methine-based, pyrazolone azo-based, barbituric acid azo-based, etc.).

[0114] Examples of the direct dye include C.I. Direct Black 17, 19, 22, 31, 32, 38, 51, 62, 71, 74, 112, 113, 154, 168, C.I. Direct Yellow 4, 8, 11, 12, 26, 27, 28, 33, 39, 44, 50, 58, 85, 86, 87, 88, 89, 98, 100, 110, C.I. Direct Red 1, 2, 4, 9, 11, 20, 23, 24, 31, 37, 39, 46, 62, 75, 79, 80, 81, 83, 89, 95, 197, 201, 218, 220, 224, 225, 226, 227, 228, 230, Examples include C.I. Direct Blue 1, 15, 22, 25, 41, 71, 76, 77, 80, 86, 90, 98, 106, 108, 199, 120, 158, 163, 168, 199, 226, etc.

[0115] Examples of acid dyes include C.I. Acid Black 1, 2, 24, 26, 31, 48, 51, 52, 107, 109, 110, 115, 119, 154, 156, C.I. Acid Yellow 1, 3, 7, 11, 17, 23, 25, 29, 36, 38, 40, 42, 44, 49, 61, 72, 78, 110, 135, 127, 141, 142, C.I. Acid Red 6, 8, 9, 13, 14, 18, 26, 27, 32, 35, 37, 42, 51, 52, 57, 80, 82, 83, 87, 89, 92, 94, 106, 111, 114, 115, 129, 131, 133, 134, 138, 145, 158, 186, 198, 249, 254, 265, 276, 289, C.I. Acid Violet 15, 17, 49, C.I. Acid Blue 1, 7, 9, 15, 22, 23, 25, 29, 40, 41, 43, 59, 62, 74, 78, 80, 83, 90, 93, 100, 102, 103, 104, 112, 113, 117, 127, 138, 158, 161, Examples include C.I. Acid Green 3, 9, 16, 25, 27, etc. Examples of basic dyes include C.I. Basic Red 1, 2, 9, 12, 13, 38, 39, 92, C.I. Basic Blue 1, 3, 7, 5, 9, 19, 24, 25, 26, 28, 45, 54, 65, Examples include C.I. Basic Black 2, 8, etc.

[0116] As the oil-soluble dye, oil-soluble dyes such as nigrosine-based, azine-based, monoazo-based, disazo-based, metal complex salt type monoazo-based, anthraquinone-based, phthalocyanine-based, triarylmethane-based dyes, oil-soluble salt-forming dyes, and oil-soluble gold-containing dyes can be used. As the oil-soluble dye, Nigrosine base EE, EEL, EX, EXBP, EB, Oil Yellow 105, 107, Oil Pink 312, Oil Scarlet 318, Oil Brown BB, GR, 416, Oil Green BG, Oil Blue 613, BOS, Oil Black HBB, 860, BS, Vari Fast Yellow 1101, 1105, 3108, 4120, 4121, Vari Fast Orange 2210, 3209, 3210, Vari Fast Red 1306, 1308, 1355, 1360, 2303, 2320, 3304, 3306, 3320, Vari Fast Pink 2310N, Vari Fast Brown 2402, 3405, Vari Fast Green 1501, Vari Fast Blue 1603, 1605, 1631, 2606, 2610, 2620, Vari Fast Violet 1701, 1702, Vari Fast Black 1807, 3804, 3806, 3808, 3810, 3820, 3830, OSP Yellow RY, ROB-B, MVB3, SP Blue 105 (above, manufactured by Orient Chemical Industries, Ltd.), Eisenspirone Yellow 3RH, GRLH Special, C-2GH, C-GNH, Eisenspirone Orange 2RH, GRH Concentration Special, Eisenspirone Red GEH, BEH, GRLH Special, C-GH, C-BH, Eisenspirone Violet RH, C-RH, Izen Spiron Brown BH Conc., RH, Izen Spiron Mahogany RH, Izen Spiron Blue GNH, 2BNH, C-RH, BPNH, Izen Spiron Green C-GH, Izen Spiron Black BNH, MH, RLH, GMH Special, BH Special, S.B.N. Orange 703, S.B.N. Violet 510, 521, S.P.T. Orange 6, S.P.T. Blue 111, SOT Pink 1, SOT Blue 4, SOT Black 1, 6, 10, 12, 13 Liquid, Izen Rhodamine B base, Izen Methyl Violet base, Izen Victoria Blue B base (all manufactured by Hodogaya Chemical Co., Ltd.), Oil Yellow CH, Oil Pink 330, Oil Blue 8B, Oil Black S, FS Special A, 2020, 109, 215, AL Yellow 1106D, 3101, AL Red 2308, Neo Super Yellow C-131, C-132, C-134, Neo Super Orange C-233, Neo Super Red C-431, Neo Super Blue C-555, Neo Super Brown C-732, C-733, (all manufactured by Chuo Gosei Kagaku Co., Ltd.) and the like can be mentioned. In addition, dyes such as natural dyes, food dyes, and plant dyes can be used.

[0117] As pigments, conventionally known organic pigments and inorganic pigments can be used. Examples of pigments include organic pigments such as azo, phthalocyanine, quinacridone, anthraquinone, dioxazine, indigo / thioindigo, perinone / perylene, isoindolinone, azomethine azo, etc., inorganic pigments such as carbon black and titanium white, colored resin emulsions, pearl pigments, aluminum pigments, bright pigments, phosphorescent pigments, fluorescent pigments, and the like can be used.

[0118] Examples of pigment compounds include perylene, perinone, quinacridone, quinacridone quinone, anthraquinone, anthraanthrone, benzimidazolone, disazo condensation, disazo, azo, indanthrone, phthalocyanine, triarylcarbonium, dioxazine, aminoanthraquinone, diketopyrrolopyrrole, indigo, thioindigo, isoindoline, isoindolinone, pyranthrone, isoviolanthrone, and the like.

[0119] More specifically, for example, perylene compound pigments such as Pigment Red 190, Pigment Red 224, Pigment Violet 29, perinone compound pigments such as Pigment Orange 43 or Pigment Red 194, quinacridone compound pigments such as Pigment Violet 19, Pigment Violet 42, Pigment Red 122, Pigment Red 192, Pigment Red 202, Pigment Red 207 or Pigment Red 209, quinacridone quinone compound pigments such as Pigment Red 206, Pigment Orange 48 or Pigment Orange 49, anthraquinone compound pigments such as Pigment Yellow 147, anthraanthrone compound pigments such as Pigment Red 168, benzimidazolone compound pigments such as Pigment Brown 25, Pigment Violet 32, Pigment Orange 36, Pigment Yellow 120, Pigment Yellow 180, Pigment Yellow 181, Pigment Orange 62 or Pigment Red 185, disazo condensation compound pigments such as Pigment Yellow 93, Pigment Yellow 94, Pigment Yellow 95, Pigment Yellow 128, Pigment Yellow 166, Pigment Orange 34, Pigment Orange 13, Pigment Orange 31, Pigment Red 144, Pigment Red 166, Pigment Red 220, Pigment Red 221, Pigment Red 242, Pigment Red 248, Pigment Red 262 or Pigment Brown 23, disazo compounds such as Pigment Yellow 13, Pigment Yellow 83 or Pigment Yellow 188, azo compounds such as Pigment Red 187, Pigment Red 170, Pigment Yellow 74, Pigment Yellow 150, Pigment Red 48, Pigment Red 53, Pigment Orange 64 or Pigment Red 247, indanthrone compound pigments such as Pigment Blue 60, phthalocyanine compound pigments such as Pigment Green 7, Pigment Green 36, Pigment Green 37, Pigment Green 58, Pigment Blue 16, Pigment Blue 75 or Pigment Blue 15, triarylcarbonium compound pigments such as Pigment Blue 56 or Pigment Blue 61, Pigment Violet 23Alternatively, dioxazine compound pigments such as Pigment Violet 37, aminoanthraquinone compound pigments such as Pigment Red 177, Pigment Red 254, Pigment Red 255, Pigment Red 264, Pigment Red 272, Pigment Orange 71, or diketopyrrolopyrrole compound pigments such as Pigment Orange 73, thioindigo compound pigments such as Pigment Red 88, isindoline compound pigments such as Pigment Yellow 139, Pigment Orange 66, isatinone compound pigments such as Pigment Yellow 109 or Pigment Orange 61, pyranthrone compound pigments such as Pigment Orange 40 or Pigment Red 216, or isoviolanthrone compound pigments such as Pigment Violet 31 may be mentioned.

[0120] The pigment may be directly contained in the dispersion according to the present disclosure or the near-infrared absorbing composition according to the present disclosure, or may be contained as a pigment dispersion after preparing a dispersion. When using a pigment as another coloring compound, the dispersion method of the pigment, the preferred particle size, etc. are the same as the examples of the pigment in the above-described near-infrared absorbing dye.

[0121] The pigment may be kneaded into known resins such as polyacrylic acid, polymethacrylic acid, styrene-acrylic acid copolymer, and their metal salts, ammonium salts, and amine salts to form a processed pigment. The processed pigment kneaded into the resin is preferable because it is easily dispersed when mixed with a solvent. As the processed pigment, commercially available processed pigments in which the pigment has already been kneaded into a dispersant may be used. Specific examples of commercially available processed pigments that can be used include MICROLITH Yellow 3G-WA, MICROLITH Yellow 2R-WA, MICROLITH Scarlet R-WA, MICROLITH Blue 4G-WA, MICROLITH Yellow 2R-A, MICROLITH Scarlet R-A, MICROLITH Blue 4G-A (manufactured by Ciba Specialty Chemicals Co., Ltd.), EM YELLOW FX-3024, EM SCARLET 2YD, EM GREEN G, EM PINK 2B, EM BLUE 2G (manufactured by Toyo Ink Co., Ltd.), SANDY ESUPE R YELLOW 1608, SANDY ESUPE R YELLOW D215, SANDY ESUPE R BLUE GLL, SANDY ESUPE R CARMINE FB (manufactured by Sanyo Color Works Co., Ltd.), and the like.

[0122] The dispersion according to the present disclosure and the near-infrared absorbing composition according to the present disclosure may contain one other coloring compound alone, or may contain two or more thereof depending on the purpose. As other coloring compounds, from the viewpoints of the relationship with specific infrared absorbing dyes, spectroscopy, and higher fastness, dyes selected from phthalocyanine, triarylmethane, squarylium, azo, metal complex type azo, methine, quinacridone, anthraquinone, perylene, benzimidazolone, dioxazine, diketopyrrolopyrrole, isoindoline, carbon black, titanium, and the like are preferable.

[0123] There is no particular limitation on the content of other coloring compounds in the dispersion according to the present disclosure and the near-infrared absorbing composition according to the present disclosure, and it can be appropriately determined according to the purpose of use of the dispersion or the near-infrared absorbing composition, the required hue, and the color density. The content of other coloring compounds is preferably 0.01% by mass to 50% by mass, more preferably 0.1% by mass to 30% by mass, and still more preferably 0.5% by mass to 20% by mass with respect to the total amount of the dispersion according to the present disclosure and the near-infrared absorbing composition according to the present disclosure. When the content of other coloring compounds is within the above range, clearer color development can be obtained, and physical properties with good handleability can be easily obtained.

[0124] There is no particular limitation on the content ratio of the squarylium dye according to the present disclosure and other coloring compounds, and it can be appropriately determined according to the purpose of use of the dispersion or the near-infrared absorbing composition, the required hue, and the color development density. In the dispersion according to the present disclosure or the near-infrared absorbing composition according to the present disclosure, the content ratio (IR / CL) of the squarylium dye (IR) according to the present disclosure and other coloring compounds (CL) is preferably 1 / 1000 to 1 / 1, more preferably 1 / 1000 to 1 / 2, still more preferably 1 / 500 to 1 / 2, and particularly preferably 1 / 200 to 1 / 2 in terms of mass ratio. When the content ratio of the squarylium dye according to the present disclosure and other coloring compounds is within the above range, there is an advantage that the hue of other coloring compounds is more easily reproducible.

[0125] <Ink for inkjet recording> The ink for inkjet recording according to the present disclosure (hereinafter, also simply referred to as "ink") contains the squarylium dye according to the present disclosure. The content of the squarylium dye according to the present disclosure is preferably 0.1% by mass to 20% by mass, more preferably 0.1% by mass to 10% by mass, and still more preferably 0.3% by mass to 7% by mass based on the total amount of the ink. Further, the ink according to the present disclosure preferably contains a polymerizable monomer and a polymerization initiator.

[0126] <Polymerizable monomer> The ink according to the present disclosure preferably contains a polymerizable monomer. In the present disclosure, the polymerizable monomer means all polymerizable monomers that can be contained in the ink. The polymerizable monomer may be only one kind of polymerizable monomer or two or more kinds of polymerizable monomers.

[0127] In the present disclosure, a monomer refers to a compound having a molecular weight of less than 1000. A polymerizable monomer refers to a compound having a polymerizable group and a molecular weight of less than 1000.

[0128] The molecular weight of the polymerizable monomer is preferably 100 or more and less than 1000, more preferably 100 to 800, and even more preferably 150 to 700. The molecular weight of the polymerizable monomer is calculated from the types and numbers of atoms constituting the polymerizable monomer.

[0129] Examples of the polymerizable monomer include a photopolymerizable monomer in which a polymerization reaction proceeds by irradiation with light, and a thermopolymerizable monomer in which a polymerization reaction proceeds by heating or irradiation with infrared rays. Examples of the photopolymerizable monomer include a polymerizable monomer having a radically polymerizable radically polymerizable group (i.e., a radically polymerizable monomer), and a polymerizable monomer having a cationically polymerizable cationically polymerizable group (i.e., a cationically polymerizable monomer). Among them, the polymerizable monomer is preferably a photopolymerizable monomer, and more preferably a radically polymerizable monomer.

[0130] The radically polymerizable monomer is preferably an ethylenically unsaturated monomer having an ethylenically unsaturated group as a radically polymerizable group. Examples of the ethylenically unsaturated monomer include a monofunctional ethylenically unsaturated monomer and a polyfunctional ethylenically unsaturated monomer.

[0131] The monofunctional ethylenically unsaturated monomer is a monomer having one ethylenically unsaturated group, and examples thereof include monofunctional (meth)acrylate, monofunctional (meth)acrylamide, monofunctional aromatic vinyl compound, monofunctional vinyl ether, and monofunctional N-vinyl compound.

[0132] Examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, tert-octyl (meth)acrylate, isoamyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, 4-n-butylcyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, bornyl (meth)acrylate, isobornyl (meth)acrylate, 2-ethylhexyldiglycol (meth)acrylate, butoxyethyl (meth)acrylate, 2-chloroethyl (meth)acrylate, 4-bromobutyl (meth)acrylate, cyanoethyl (meth)acrylate, benzyl (meth)acrylate, butoxymethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-(2-methoxyethoxy)ethyl (meth)acrylate, 2-(2-butoxyethoxy)ethyl (meth)acrylate, ethyl carbitol (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 1H,1H,2H,2H-perfluorodecyl (meth)acrylate, 4-butylphenyl (meth)acrylate, phenyl (meth)acrylate, 2,4,5-Tetramethylphenyl (meth)acrylate, 4-chlorophenyl (meth)acrylate, 2-phenoxymethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, glycidyl (meth)acrylate, glycidyloxybutyl (meth)acrylate, glycidyloxyethyl (meth)acrylate, glycidyloxypropyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, diethylaminopropyl (meth)acrylate, trimethoxysilylpropyl (meth)acrylate, trimethylsilylpropyl (meth)acrylate, polyethylene oxide monomethyl ether (meth)acrylate, polyethylene oxide (meth)acrylate, polyethylene oxide monoalkyl ether (meth)acrylate, dipropylene glycol (meth)acrylate, polypropylene oxide monoalkyl ether (meth)acrylate, 2-methacryloyloxyethyl succinate, 2-methacryloyloxyhexahydrophthalate, 2-methacryloyloxyethyl-2-hydroxypropyl phthalate, butoxydiethylene glycol (meth)acrylate, trifluoroethyl (meth)acrylate, perfluorooctylethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, ethylene oxide (EO) modified phenol, Examples of the mono-functional (meth)acrylate include (meth)acrylate, EO-modified cresol (meth)acrylate, EO-modified nonylphenol (meth)acrylate, propylene oxide (PO)-modified nonylphenol (meth)acrylate, EO-modified 2-ethylhexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyl oxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, (3-ethyl-3-oxetanylmethyl)(meth)acrylate, phenoxyethylene glycol (meth)acrylate, and cyclic trimethylolpropane formal (meth)acrylate.

[0133] Examples of the mono-functional (meth)acrylamide include (meth)acrylamide, N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-propyl (meth)acrylamide, N-n-butyl (meth)acrylamide, N-t-butyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-methylol (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, and (meth)acryloylmorpholine.

[0134] Examples of the mono-functional aromatic vinyl compound include styrene, dimethylstyrene, trimethylstyrene, isopropylstyrene, chloromethylstyrene, methoxystyrene, acetoxystyrene, chlorostyrene, dichlorostyrene, bromostyrene, methyl vinyl benzoate, 3-methylstyrene, 4-methylstyrene, 3-ethylstyrene, 4-ethylstyrene, 3-propylstyrene, 4-propylstyrene, 3-butylstyrene, 4-butylstyrene, 3-hexylstyrene, 4-hexylstyrene, 3-octylstyrene, 4-octylstyrene, 3-(2-ethylhexyl)styrene, 4-(2-ethylhexyl)styrene, allylstyrene, isopropenylstyrene, butenylstyrene, octenylstyrene, 4-t-butoxycarbonylstyrene, and 4-t-butoxystyrene.

[0135] Examples of the monofunctional vinyl ether include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, cyclohexylmethyl vinyl ether, 4-methylcyclohexylmethyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl ether, methoxypolyethylene glycol vinyl ether, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxymethylcyclohexylmethyl vinyl ether, diethylene glycol monovinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether, chloroethoxyethyl vinyl ether, phenylethyl vinyl ether, and phenoxypolyethylene glycol vinyl ether.

[0136] Examples of the monofunctional N-vinyl compound include N-vinyl-ε-caprolactam and N-vinylpyrrolidone.

[0137] From the viewpoint of improving curability, the monofunctional ethylenically unsaturated compound is preferably a compound having a ring structure. Examples of the monofunctional ethylenically unsaturated compound having a ring structure include cyclohexyl (meth)acrylate, 4-n-butylcyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, bornyl (meth)acry Rate, isobornyl (meth) acrylate, benzyl (meth) acrylate, 4-butylphenyl (meth) acrylate, phenyl (meth) acrylate, 2,4,5-trimethylphenyl (meth) acrylate, 4-chlorophenyl (meth) acrylate, 2-phenoxymethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyl oxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, (3-ethyl-3-oxetananylmethyl) (meth) acrylate, phenoxyethylene glycol (meth) acrylate, cyclic trimethylolpropane formal (meth) acrylate and other monofunctional (meth) acrylates having a ring structure; Monofunctional aromatic vinyl compounds; Monofunctional vinyl ethers having a ring structure such as cyclohexyl vinyl ether, cyclohexylmethyl vinyl ether, 4-methylcyclohexylmethyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, phenylethyl vinyl ether, phenoxypolyethylene glycol vinyl ether; Examples of monofunctional N-vinyl compounds having a ring structure include N-vinyl-ε-caprolactam and N-vinylpyrrolidone.

[0138] A polyfunctional ethylenically unsaturated monomer is a monomer having two or more ethylenically unsaturated groups, and examples thereof include polyfunctional (meth) acrylates and polyfunctional vinyl ethers.

[0139] Examples of the polyfunctional (meth)acrylate include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, hexanediol di(meth)acrylate, heptanediol di(meth)acrylate, EO-modified neopentyl glycol di(meth)acrylate, PO-modified neopentyl glycol di(meth)acrylate, EO-modified hexanediol di(meth)acrylate, PO-modified hexanediol di(meth)acrylate, octanediol di(meth)acrylate, nonanediol di(meth)acrylate, decanediol di(meth)acrylate, dodecanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, glycerin di(meth)acrylate, pentaerythritol di(meth)acrylate, ethylene glycol diglycidyl ether di(meth)acrylate, diethylene glycol diglycidyl ether di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane EO adduct tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tri(meth)acryloyloxyethoxy trimethylolpropane, glycerin polyglycidyl ether poly(meth)acrylate, tris(2-acryloyloxyethyl) isocyanurate and Examples include 2-(2-vinyloxyethoxy)ethyl (meth)acrylate.

[0140] Examples of the polyfunctional vinyl ether include 1,4-butanediol divinyl ether, ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, bisphenol A alkylene oxide divinyl ether, bisphenol F alkylene oxide divinyl ether, trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol hexavinyl ether, EO-added trimethylolpropane trivinyl ether, PO-added trimethylolpropane trivinyl ether, EO-added ditrimethylolpropane tetravinyl ether, PO-added ditrimethylolpropane tetravinyl ether, EO-added pentaerythritol tetravinyl ether, PO-added pentaerythritol tetravinyl ether, EO-added dipentaerythritol hexavinyl ether, and PO-added dipentaerythritol hexavinyl ether.

[0141] From the viewpoint of improving curability, the polyfunctional ethylenically unsaturated monomer is preferably a compound having an oxygen atom, and the ratio of the number of oxygen atoms to the number of carbon atoms contained in one molecule is preferably 0.2 or more, more preferably 0.3 or more. The upper limit value of the ratio is not particularly limited, and for example, it is 0.5. Examples of the compound having a ratio of the number of oxygen atoms to the number of carbon atoms contained in one molecule of 0.2 or more include polyethylene glycol diacrylate.

[0142] The polymerizable monomer may also be a commercially available product described in "Crosslinking Agent Handbook" edited by Shinzo Yamashita (Daishesha, 1981); "UV / EB Curing Handbook (Raw Material Edition)" edited by Kiyomi Kato (Polymer Publishing Society, 1985); "Applications and Markets of UV / EB Curing Technology" edited by the Radtech Research Group, page 79 (CMC, 1989); "Polyester Resin Handbook" written by Eiichiro Takiyama (Nikkkan Kogyo Shimbun, 1988), etc.

[0143] The ink according to the present disclosure preferably contains a polyfunctional polymerizable monomer as the polymerizable monomer, and more preferably contains a monofunctional polymerizable monomer and a polyfunctional polymerizable monomer. By containing a polyfunctional polymerizable monomer in the ink, an image excellent in curability can be recorded. Further, by containing a polyfunctional polymerizable monomer in the ink, the phenomenon (so-called migration) in which unreacted polymerizable monomer transfers to the outside from the image recording material can be suppressed. In particular, it is excellent in that it can be applied to packaging materials in the food packaging field and the cosmetic packaging field where strict safety requirements are imposed on the base material.

[0144] From the viewpoint of curability, the proportion of the polyfunctional polymerizable monomer in the polymerizable monomer contained in the ink is preferably 50% by mass or more, and more preferably 60% by mass or more. Further, the upper limit value of the proportion of the polyfunctional polymerizable monomer in the polymerizable monomer contained in the ink is not particularly limited, and it may be 100% by mass.

[0145] From the viewpoint of further improving the alcohol resistance of the near-infrared absorption image, the proportion of the monofunctional polymerizable monomer in the polymerizable monomer contained in the ink is preferably 50% by mass or less, and more preferably 40% by mass or less. Also, the proportion of the monofunctional polymerizable monomer in the polymerizable monomer contained in the ink may be 0 % by mass.

[0146] The proportion of the polymerizable monomer in the total amount of the ink according to the present disclosure is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass or more. The upper limit of the polymerizable monomer in the total amount of the ink according to the present disclosure depends on the amounts of other components, and is, for example, 95% by mass, 90% by mass, etc.

[0147] In the present disclosure, from the viewpoint of improving the readability after the rubbing test and the solvent resistance, the polymerizable monomer preferably has a glass transition temperature (Tg) of 30°C or higher, more preferably 60°C or higher. In particular, the proportion of the polymerizable monomer having a glass transition temperature of 30°C or higher in the polymerizable monomer is preferably 90% by mass or more, more preferably 92% by mass or more. The upper limit value of the above proportion is not particularly limited, and is, for example, 100% by mass. When the proportion of the polymerizable monomer having a glass transition temperature of 30°C or higher in the polymerizable monomer is 90% by mass or more, the readability after the rubbing test is further improved. Examples of the polymerizable monomer having a Tg of 30°C or higher include isobornyl (meth)acrylate (Tg: 97°C).

[0148] Note that the glass transition temperature (Tg) of the polymerizable monomer means the glass transition temperature when the polymerizable monomer (A) is a homopolymer. An arbitrary polymerization initiator is added to the polymerizable monomer (A) to obtain a homopolymer having a weight average molecular weight of 10,000 to 20,000. The glass transition temperature (Tg) of the homopolymer having a weight average molecular weight of 10,000 to 20,000 is adopted as the glass transition temperature of the polymerizable monomer (A). Although the glass transition temperature (Tg) of the homopolymer varies depending on the weight average molecular weight, in the range where the weight average molecular weight is 10,000 to 20,000, the variation in Tg due to the difference in the weight average molecular weight is negligible. Note that the weight average molecular weight means a value measured by gel permeation chromatography (GPC). The measurement by GPC is performed using HLC (registered trademark)-8020GPC (manufactured by Tosoh Corporation) as a measuring device, three TSKgel (registered trademark) Super Multipore HZ-H (4.6 mm ID × 15 cm, manufactured by Tosoh Corporation) columns, and THF (tetrahydrofuran) as an eluent. The measurement is carried out at a sample concentration of 0.45 mass%, a flow rate of 0.35 ml / min, a sample injection volume of 10 μl, and a measurement temperature of 40°C, using a differential refractive index (RI) detector. The calibration curve is prepared from eight samples of "Standard sample TSK standard, polystyrene" manufactured by Tosoh Corporation: "F-40", "F-20", "F-4", "F-1", "A-5000", "A-2500", "A-1000", and "n-propylbenzene".

[0149] The glass transition temperature (Tg) is measured using a differential scanning calorimeter (DSC) in accordance with ASTM D3418-8. For example, the glass transition temperature (Tg) is measured under normal measurement conditions using a differential scanning calorimeter (product name "EXSTAR6220") manufactured by SII NanoTechnology Inc.

[0150] <Polymerization initiator> The ink according to the present disclosure preferably contains a polymerization initiator. In the present disclosure, the polymerization initiator means all the polymerization initiators that can be contained in the ink. The polymerization initiator may be only one kind of compound or two or more kinds of compounds. When the polymerizable monomer in the ink according to the present disclosure contains a radical polymerizable monomer, the polymerization initiator preferably contains a radical polymerization initiator.

[0151] Examples of the radical polymerization initiator include alkylphenone compounds, acylphosphine compounds, aromatic onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon-halogen bond, and alkylamine compounds.

[0152] Examples of the acylphosphine oxide compound include monoacylphosphine oxide compounds and bisacylphosphine oxide compounds, and bisacylphosphine oxide compounds are preferred.

[0153] Examples of the monoacylphosphine oxide compound include isobutyryldiphenylphosphine oxide, 2-ethylhexanoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide, o-tolyldiphenylphosphine oxide, p-t-butylbenzoyldiphenylphosphine oxide, 3-pyridylcarbonyldiphenylphosphine oxide, acryloyldiphenylphosphine oxide, benzoyldiphenylphosphine oxide, vinyl pivaloyl phenylphosphinate, adipoyl bisdiphenylphosphine oxide, pivaloyldiphenylphosphine oxide, p-tolyldiphenylphosphine oxide, 4-(t-butyl)benzoyldiphenylphosphine oxide, terephthaloyl bisdiphenylphosphine oxide, 2-methylbenzoyldiphenylphosphine oxide, versatoyldiphenylphosphine oxide, 2-methyl-2-ethylhexanoyldiphenylphosphine oxide, 1-methyl-cyclohexanoyldiphenylphosphine oxide, methyl pivaloyl phenylphosphinate and isopropyl pivaloyl phenylphosphinate.

[0154] Examples of the bisacylphosphine oxide compound include bis(2,6-dichloro benzene Zoyl)phenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-ethoxyphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2-naphthylphosphine oxide, bis(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-chlorophenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,4-dimethoxyphenylphosphine oxide, bis(2,6-dichlorobenzoyl)decylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-octylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,6-dichloro-3,4,5-trimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,6-dichloro-3,4,5-trimethoxybenzoyl)-4-ethoxyphenylphosphine oxide, bis(2-methyl-1-naphthoyl)-2,5-dimethylphenylphosphine oxide, bis(2-methyl-1-naphthoyl)-4-ethoxyphenylphosphine oxide, bis(2-methyl-1-naphthoyl)-2-naphthylphosphine oxide, bis(2-methyl-1-naphthoyl)-4-propylphenylphosphine oxide, bis(2-methyl-1-naphthoyl)-2,5-dimethylphenylphosphine oxide, bis(2-methoxy-1-naphthoyl)-4-ethoxyphenylphosphine oxide, bis(2-chloro-1-naphthoyl)-2,5-dimethylphenylphosphine oxide and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide.

[0155] Among them, as the acylphosphine oxide compound, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (product name: "Omnirad 819", manufactured by IGM Resins B.V.), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (product name: "Omnirad TPO H", manufactured by IGM Resins B.V.) or (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide (product name: "Omnirad TPO-L", manufactured by IGM Resins B.V.) is preferable.

[0156] Examples of thioxanthone compounds include thioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dichlorothioxanthone, 2-dodecylthioxanthone, 2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, 1-methoxycarbonylthioxanthone, 2-ethoxycarbonylthioxanthone, 3-(2-methoxyethoxycarbonyl)thioxanthone, 4-butoxycarbonylthioxanthone, 3-butoxycarbonyl-7-methylthioxanthone, 1-cyano-3-chlorothioxanthone, 1-ethoxycarbonyl-3-chlorothioxanthone, 1-ethoxycarbonyl-3-ethoxythioxanthone, 1-ethoxycarbonyl-3-aminothioxanthone, 1-ethoxycarbonyl-3-phenylsulfurylthioxanthone, 3,4-di[2-(2-methoxyethoxy)ethoxycarbonyl]thioxanthone, 1-ethoxycarbonyl-3-(1-methyl-1-morpholinoethyl)thioxanthone, 2-methyl-6-dimethoxymethylthioxanthone, 2-methyl-6-(1,1-dimethoxybenzyl)thioxanthone, 2-morpholinomethylthioxanthone, 2-methyl-6-morpholinomethylthioxanthone, n-allylthioxanthone-3,4-dicarboximide, n-octylthioxanthone-3,4-dicarboximide, N-(1,1,3,3-tetramethylbutyl)thioxanthone-3,4-dicarboximide, 1-phenoxythioxanthone, 6-ethoxycarbonyl-2-methoxythioxanthone, 6-ethoxycarbonyl-2-methylthioxanthone, thioxanthone-2-polyethylene glycol ester, and 2-hydroxy-3-(3,4-dimethyl-9-oxo-9 H-thioxanthon-2-yloxy)-N,N,N-trimethyl-1-propanaminium chloride.

[0157] The thioxanthone compound may be a commercially available product. Examples of commercially available products include the SPEEDCURE series manufactured by Lambson (e.g., SPEEDCURE 7010, SPEEDCURE 7010L, SPEEDCURE CPTX, SPEEDCURE ITX, etc.).

[0158] From the viewpoint of further improving the alcohol resistance of the near-infrared absorption image, the content of the polymerization initiator is preferably 5% by mass or more, more preferably 10% by mass or more, based on the total amount of the ink. The upper limit of the content of the polymerization initiator is not particularly limited, and is, for example, 30% by mass.

[0159] When the polymerization initiator contains an acylphosphine oxide compound, the content of the acylphosphine oxide compound is preferably 5% by mass to 15% by mass, more preferably 8% by mass to 12% by mass, based on the total amount of the ink, from the viewpoint of further improving the alcohol resistance of the near-infrared absorption image.

[0160] When the polymerization initiator contains a thioxanthone compound, the content of the thioxanthone compound is preferably 0.5% by mass to 5% by mass, more preferably 1% by mass to 3% by mass, based on the total amount of the ink, from the viewpoint of further improving the alcohol resistance of the near-infrared absorption image.

[0161] <Dispersant> The ink according to the present disclosure preferably contains at least one dispersant. The dispersant has a function of dispersing the near-infrared absorption dye (D).

[0162] The weight average molecular weight of the dispersant is preferably 100,000 or less, more preferably 75,000 or less, and still more preferably 50,000 or less. When the weight average molecular weight of the dispersant is 100,000 or less, the diffusion rate of the dispersant into the dispersion medium is improved, and an image recording material excellent in readability can be obtained. The weight average molecular weight of the dispersant is preferably 1,000 or more, more preferably 2,000 or more, and still more preferably 3,000 or more. When the weight average molecular weight of the dispersant is 1,000 or more, the compatibility with the dispersion medium does not become too high, and the near-infrared absorption dye represented by Formula 1 can be stably dispersed by the dispersant.

[0163] The dispersant is preferably a polymer, and the polymer may be any of a random polymer, a block polymer, and a graft polymer.

[0164] Among them, from the viewpoint of readability over time, the dispersant is preferably a block polymer. The block polymer has, for example, an adsorption block having an adsorption group that adsorbs to the near-infrared absorbing dye represented by Formula 1 and a dispersion medium affinity block having a functional group having an affinity for the dispersion medium. In the block polymer, since the shielding property of the adsorption group is low and the motility is high, the adsorption rate to the near-infrared absorbing dye represented by Formula 1 is fast. Therefore, when the dispersant is a block polymer, the readability is further improved. Further, in the block polymer, since the adsorption groups are aggregated, the adsorption force for the near-infrared absorbing dye represented by Formula 1 is high. Therefore, when the dispersant is a block polymer, the readability over time is further improved.

[0165] The dispersant preferably has a basic functional group or an acidic functional group. When the pigment derivative described later is contained in the ink, a combination of a dispersant having a basic functional group and a pigment derivative having an acidic functional group, or a combination of a dispersant having an acidic functional group and a pigment derivative having a basic functional group is preferable. When a dispersant having a basic functional group and a pigment derivative having an acidic functional group are combined and contained in the ink, the pigment derivative is likely to be adsorbed to the dispersant by acid-base interaction. Similarly, when a dispersant having an acidic functional group and a pigment derivative having a basic functional group are combined and contained in the ink, the pigment derivative is likely to be adsorbed to the dispersant by acid-base interaction. Due to the steric repulsion between the dispersants, the near-infrared absorbing dye represented by Formula 1 can be stably dispersed in the ink, and the stability over time is improved. As a result, the readability over time is improved. When a dispersant having a basic functional group and a pigment derivative having an acidic functional group are combined and contained in the ink, the pigment derivative is likely to be adsorbed to the dispersant by acid-base interaction. Due to the steric repulsion between the dispersants, the near-infrared absorbing dye represented by Formula 1 can be stably dispersed in the ink, and the stability over time is improved. As a result, the readability over time is improved.

[0166] Examples of the basic functional group include an amino group, an amide group, and an imino group. The dispersant may have only one kind of basic functional group or may have two or more kinds of basic functional groups.

[0167] Examples of the acidic functional group include a carboxy group and a sulfo group. The dispersant may have only one type of acidic functional group, or may have two or more types of acidic functional groups.

[0168] When the dispersant is a dispersant having a basic functional group, from the viewpoint of improving readability and readability after aging, the base number of the dispersant is preferably 15 mgKOH / g or more, more preferably 20 mgKOH / g or more, and still more preferably 25 mgKOH / g or more. The upper limit value of the base number of the dispersant is not particularly limited, and for example, it is 40 mgKOH / g.

[0169] In the present disclosure, the base number is a value measured by the perchloric acid method defined by JIS K 2501:2003. The base number is obtained as the number of milligrams (mg) of potassium hydroxide equivalent to hydrochloric acid or perchloric acid required to neutralize all basic components contained in 1 g of the sample.

[0170] When the dispersant is a dispersant having an acidic functional group, from the viewpoint of improving readability and readability after aging, the acid value of the dispersant is preferably 15 mgKOH / g or more, more preferably 20 mgKOH / g or more, and still more preferably 25 mgKOH / g or more. The upper limit value of the acid value of the dispersant is not particularly limited, and for example, it is 40 mgKOH / g.

[0171] In the present disclosure, the acid value is a value measured by the method described in JIS K0070:1992. The acid value is obtained as the number of milligrams (mg) of potassium hydroxide required to neutralize all acidic components contained in 1 g of the sample.

[0172] The dispersant may be a commercially available product. Examples of commercially available products include the SOLSPERSE (registered trademark) series of Lubrizol Corporation (e.g., SOLSPERSE 16000, 21000, 32000, 35000, 41000, 41090, 43000, 44000, 46000, 54000, 55000, 71000, etc.), the DISPERBYK (registered trademark) series of BYK (e.g., DISPERBYK 102, 110, 111, 118, 170, 190, 194N, 2001, 2013, 2015, 2090, 2096, etc.), the TEGO (registered trademark) Dispers series of Evonik (e.g., TEGO Dispers 610, 610S, 630, 651, 655, 750W, 755W, etc.), the Disparon (registered trademark) series of Kusumoto Chemical Co., Ltd. (e.g., DA-375, DA-1200, etc.), the Floren series of Kyoei Chemical Industry Co., Ltd. (e.g., WK-13E, G-700, G-900, GW-1500, GW-1640, WK-13E, etc.), the EFKA (registered trademark) series of BASF (e.g., EFKA PX 4701, EFKA PX 4731, EFKA PX 4732, etc.).

[0173] From the viewpoint of improving readability and readability over time, the content of the dispersant is preferably 0.7% by mass to 5% by mass, more preferably 0.8% by mass to 4% by mass, based on the total amount of the ink.

[0174] The ratio of the content of the dispersant to the content of the squarylium dye according to the present disclosure is preferably 0.1 to 20, more preferably 0.2 to 5, and even more preferably 0.5 to 5 on a mass basis.

[0175] <Pigment Derivative> The ink according to the present disclosure preferably further contains at least one pigment derivative.

[0176] A pigment derivative is a compound having a structure derived from a pigment in the molecule and a molecular weight of less than 1000.

[0177] When the ink contains a pigment derivative, π-π interaction occurs between the pigment derivative and the near-infrared absorbing dye represented by Formula 1, and acid-base interaction occurs between the pigment derivative and the dispersant. Therefore, the near-infrared absorbing dye represented by Formula 1 is more stably dispersed by the dispersant, and the stability of the ink over time is improved. As a result, the readability after aging is improved.

[0178] The pigment derivative preferably has a basic functional group or an acidic functional group.

[0179] Examples of the basic functional group include an amino group, an amide group, and an imino group. The pigment derivative may have only one kind of basic functional group or two or more kinds of basic functional groups.

[0180] Examples of the acidic functional group include a carboxy group and a sulfo group. The pigment derivative may have only one kind of acidic functional group or two or more kinds of acidic functional groups.

[0181] The ink may contain one kind of pigment derivative or two or more kinds of pigment derivatives. From the viewpoint of improving the readability and the readability after aging, the content of the pigment derivative is preferably 0.005% by mass to 0.1% by mass based on the total amount of the ink.

[0182] From the viewpoint of improving the readability and the readability after aging, the content of the pigment derivative is preferably 0.12% by mass to 15% by mass based on the total amount of the near-infrared absorbing dye represented by Formula 1, and more preferably 0.15% by mass to 12% by mass.

[0183] The ink according to the present disclosure may further contain the following other components.

[0184] <Polymerization inhibitor> The ink according to the present disclosure preferably contains a polymerization inhibitor. The ink may contain one kind of polymerization inhibitor or two or more kinds of polymerization inhibitors.

[0185] Examples of the polymerization inhibitor include hydroquinone compounds, phenothiazine, catechols, alkylphenols, alkylbisphenols, zinc dimethyldithiocarbamate, copper dimethyldithiocarbamate, copper dibutyldithiocarbamate, copper salicylate, thiodipropionate esters, mercaptobenzimidazole, phosphites, nitrosoamine compounds, hindered amine compounds, and nitroxyl radicals.

[0186] Among them, the polymerization inhibitor is preferably at least one selected from the group consisting of nitrosoamine compounds, hindered amine compounds, hydroquinone compounds, and nitroxyl radicals, more preferably at least one selected from the group consisting of nitrosoamine compounds, hydroquinone compounds, and nitroxyl radicals, and even more preferably contains nitrosoamine compounds, hydroquinone compounds, and nitroxyl radicals.

[0187] Examples of the nitrosoamine compounds include N-nitroso-N-phenylhydroxylamine aluminum salt and N-nitroso-N-phenylhydroxylamine. Among them, the nitrosoamine compound is preferably N-nitroso-N-phenylhydroxylamine aluminum salt.

[0188] The hindered amine compound is a compound having a hindered amine structure in the molecule. Examples of the hindered amine compound include the compounds described in JP-A-61-91257. Among them, the hindered amine compound preferably has a structure in which all hydrogens on the carbons at the 2- and 6-positions of piperidine are substituted with methyl groups, and is a derivative of 2,2,6,6-tetramethylpiperidine. Examples of the hindered amine compound include 4-benzoyloxy-2,2,6,6-tetramethylpiperidine and 1-(3,5-di-tert-butyl-4-hydroxy-phenylpropionyloxyethyl)-4-(3,5-di-tert-butyl-4-hydroxy-phenylpropionyloxy)-2,2,6,6-tetramethylpiperidine.

[0189] Examples of the hydroquinone compound include hydroquinone, methylhydroquinone, t-butylhydroquinone, and p-methoxyphenol. Among them, the hydroquinone compound is preferably p-methoxyphenol.

[0190] Examples of the nitroxyl radical include 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl (TEMPOL). Among them, the nitroxyl radical is preferably 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl (TEMPOL).

[0191] From the viewpoint of improving the temporal stability of the ink, the content of the polymerization inhibitor is preferably 1% by mass or more, more preferably 1.5% by mass or more, based on the total amount of the ink. The upper limit of the content of the polymerization inhibitor is not particularly limited, but from the viewpoint of polymerizability, it is preferably 5% by mass.

[0192] When the polymerization inhibitor contains a nitrosoamine compound, the content of the nitrosoamine compound is preferably 0.5% by mass to 5% by mass, more preferably 0.5% by mass to 2% by mass, based on the total amount of the ink, from the viewpoint of improving the temporal stability of the ink.

[0193] When the polymerization inhibitor contains a hydroquinone compound, the content of the hydroquinone compound is preferably 0.1% by mass to 5% by mass, more preferably 0.5% by mass to 2% by mass, based on the total amount of the ink, from the viewpoint of improving the temporal stability of the ink.

[0194] <Sensitizer> When the ink according to the present disclosure contains a polymerization initiator, it may contain a sensitizer together with the polymerization initiator. When the ink contains a sensitizer, the curability is improved, and particularly the curability when using an LED light source is improved. In addition, the sensitizer also contributes to the improvement of the light resistance of the ink.

[0195] A sensitizer is a substance that absorbs specific active energy rays and enters an electronically excited state. The sensitizer in the electronically excited state comes into contact with a photoinitiator, causing effects such as electron transfer, energy transfer, and heat generation. As a result, the chemical change of the photoinitiator is promoted.

[0196] Examples of the sensitizer include ethyl 4-(dimethylamino)benzoate (EDB), anthraquinone, 3-acylcoumarin derivatives, terphenyl, styryl ketone, 3-(aroylmethylene)thiazoline, camphorquinone, eosin, rhodamine, erythrosine, the compound represented by the general formula (i) described in JP-A-2010-24276, and the compound represented by the general formula (I) described in JP-A-6-107718.

[0197] When the ink contains a sensitizer, the content of the sensitizer is preferably 1.0% by mass to 15.0% by mass, more preferably 1.5% by mass to 10.0% by mass, and even more preferably 2.0% by mass to 6.0% by mass based on the total amount of the ink. is even more preferable.

[0198] <Organic solvent> The ink according to the present disclosure may contain at least one organic solvent. Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone, and diethyl ketone; alcohols such as methanol, ethanol, 2-propanol, 1-propanol, 1-butanol, and tert-butanol; chlorine-based solvents such as chloroform and methylene chloride; aromatic solvents such as benzene and toluene; ester solvents such as ethyl acetate, butyl acetate, isopropyl acetate, ethyl lactate, butyl lactate, and isopropyl lactate; ether solvents such as diethyl ether, tetrahydrofuran, and dioxane; glycol ether solvents such as ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, and propylene glycol monomethyl ether; and glycol ether acetate solvents such as propylene glycol monomethyl ether acetate.

[0199] When the ink according to the present disclosure contains an organic solvent, the content of the organic solvent is preferably 5% by mass or less, more preferably 2% by mass or less, based on the total amount of the ink. The ink according to the present disclosure may have a composition that does not contain an organic solvent (i.e., the content of the organic solvent is 0% by mass based on the total amount of the ink).

[0200] <Resin> The ink according to the present disclosure preferably contains a resin. When a resin is contained in the ink, a near-infrared absorption image excellent in alcohol resistance can be obtained. The resin referred to herein does not have an action of dispersing the squarylium dye according to the present disclosure and is distinguished from the above dispersant. Further, the resin referred to herein does not have a polymerizable group and is distinguished from the above polymerizable monomer.

[0201] Examples of the resin include acrylic resin, cellulose derivative, epoxy resin, polyester, polyurethane, polyamide, polyvinyl chloride, polyimide, phenol resin, and silicone resin.

[0202] Among them, from the viewpoint of dispersion stability, the resin is preferably an acrylic resin. That is, the ink according to the present disclosure preferably contains an acrylic resin. In the present disclosure, the "acrylic resin" refers to a polymer containing a structural unit derived from a (meth)acrylic compound.

[0203] (Meth)acrylic compound is a compound having an acryloyl group (CH2=CH-C(=O)-) or a methacryloyl group (CH2=C(CH3)-C(=O)-). (Meth)acrylic compounds include, for example, (meth)acrylic acid, (meth)acrylic acid esters, and (meth)acrylamides.

[0204] The acrylic resin is preferably a polymer containing a structural unit derived from a (meth)acrylic acid ester, more preferably a polymer containing a structural unit derived from methyl (meth)acrylate, and even more preferably poly(methyl (meth)acrylate).

[0205] From the viewpoint of improving the alcohol resistance of the near-infrared absorption image, the content of the acrylic resin is preferably 0.5% by mass to 2% by mass based on the total amount of the ink.

[0206] From the viewpoint of improving the alcohol resistance of the near-infrared absorption image, when the total amount of the polymerizable monomer is 100 parts by mass, the content of the acrylic resin is preferably 0.40 part by mass to 1.70 parts by mass. parts by mass.

[0207] From the viewpoint of ejection properties when ejecting the ink by an inkjet recording method, the weight average molecular weight of the resin is preferably 5000 to 100000, and more preferably 10000 to 75000.

[0208] From the viewpoint of ejection properties, the content of the component having a molecular weight of 1000 or more in the whole ink is preferably 6.5% by mass or less based on the total amount of the ink. From the viewpoint of ejection properties, there is no particular limitation on the lower limit of the content of the component having a molecular weight of 1000 or more in the whole ink. The content of the component having a molecular weight of 1000 or more in the whole ink may be 0.5% by mass or more, 1.0% by mass or more, or 2.0% by mass or more.

[0209] The ink according to the present disclosure may further contain additives such as a surfactant such as a siloxane compound, an ultraviolet absorber, a co-sensitizer, an antioxidant, a fading inhibitor, and a conductive salt. For the additives, known documents such as JP-A-2011-225848 and JP-A-2009-209352 can be appropriately referred to.

[0210] <Physical properties> The viscosity of the ink according to the present disclosure is preferably 10 mPa·s to 50 mPa·s, more preferably 10 mPa·s to 30 mPa·s, and even more preferably 10 mPa·s to 25 mPa·s. The viscosity is a value measured at 25°C using a viscometer. The viscosity is measured, for example, using a VISCOMETER TV-22 type viscometer (manufactured by Toki Sangyo Co., Ltd.).

[0211] The surface tension of the ink according to the present disclosure is preferably 20 mN / m to 45 mN / m, and more preferably 20 mN / m to 30 mN / m. The surface tension is a value measured at 25°C using a surface tension meter. The surface tension is measured, for example, using DY-700 (manufactured by Kyowa Interface Science Co., Ltd.).

[0212] (Resin molded body) The resin molded body according to the present disclosure includes the squarylium dye according to the present disclosure and a resin. The resin molded body according to the present disclosure can further include a colorant. The resin used for the resin molded body is not particularly limited as long as a resin composition containing the squarylium dye according to the present disclosure can be prepared. In the present disclosure, the resin includes general synthetic resins. Among the resins, a thermoplastic resin is preferable from the viewpoint of easy molding. Examples of the thermoplastic resin include polyester, polystyrene, polyamide, polyurethane, polycarbonate, cellulose acetate, polyacrylic, polyacetal, polypropylene, polyvinyl, polysulfone, polyimide, polyolefin, etc., and at least one resin selected from the group consisting of polyester, polyamide, and polyurethane is preferable. The resin may contain only one kind or two or more kinds.

[0213] The colorant used for the resin molded body is not particularly limited, and a known colorant can be used, and the other coloring compounds described above can also be used. When the resin composition contains a colorant, the colorant may contain only one kind or two or more kinds. When using a colorant, the content is preferably 0.0001% by mass to 20% by mass, more preferably 0.001% by mass to 10% by mass, based on the total amount of the resin molded body.

[0214] In the resin molded body according to the present disclosure, further, if necessary, for the purpose of improving impact resistance, antibacterial property, gas barrier property, conductivity, magnetism, piezoelectricity, vibration damping property, sound insulation property, slidability, electromagnetic wave absorption property, flame retardancy, water repellency, deodorization property, antiblocking property, oil absorption property, water absorption property, moldability, etc., an inorganic filler can be further blended. Examples of the inorganic filler include carbon fiber, glass fiber, glass flake, zeolite, mica, graphite, metal powder, ferrite, alumina, barium titanate, potassium titanate, barium sulfate lithium, Teflon (registered trademark) powder, talc, charcoal powder, carbon nanotube (CNT), carbon microcoil (CMC), antimony oxide, aluminum hydroxide, magnesium hydroxide, hydrotalcite, calcium oxide, silica, calcium carbonate, etc. The inorganic filler is preferably blended to such an extent that it does not reduce the transparency of the resin molded body.

[0215] In addition, the resin molded body according to the present disclosure can be appropriately selected and blended with known additives such as a leveling agent, a pigment dispersant, an ultraviolet absorber, an antioxidant, a viscosity modifier, a light stabilizer, a heat stabilizer, a metal deactivator, a peroxide decomposer, a processing stabilizer, a nucleating agent, a crystallization accelerator, a crystallization retarder, a gelation inhibitor, a filler, a reinforcing agent, a plasticizer, a lubricant, a flame retardant, a rust preventive, a fluorescent brightening agent, a fluidity modifier, an antistatic agent, etc.

[0216] The shape and use of the resin molded body are not particularly limited, and it can be processed into various molded bodies. Specific examples of the form of the resin molded body include, for example, a resin film; a synthetic fiber; a resin container such as a bottle, a cosmetic container, a food container, etc.; a resin plate; a lens; a toner; exterior parts of various household appliances and electronic devices including general ornaments; interior building materials parts such as interior materials and exterior materials; interior and exterior parts of aircraft, vehicles, etc.; and the like, and forms of resin molded bodies used for various applications can be mentioned. Furthermore, examples of the resin molded body include resin pellets or granular resins that can be used as raw materials for the various resin molded bodies described above. Among them, the resin molded body according to the present disclosure has an unchanged color tone of the resin, maintains infrared absorption ability for a long time, and the heat-molded resin molded body maintains good infrared absorption ability. Therefore, when used in resin films, synthetic fibers, etc., a near-infrared absorbing resin film and a near-infrared absorbing synthetic resin can be obtained, and it can be said that the effects in the present disclosure are remarkable. In addition, the resin molded body according to the present disclosure can also be suitably applied to resin pellets or resin particles as resin raw materials to be subjected to heat molding.

[0217] There is no particular limitation on the method for manufacturing the resin molded body, and known resin molding methods can be appropriately applied. As an example, the squarylium dye according to the present disclosure and resin chips are mixed at a predetermined content, and other optional components such as a colorant are added as necessary, and a resin composition is obtained by mixing or melt-kneading, etc., and the obtained resin composition can be molded by any method.

[0218] <Other applications> In addition to those described above, the uses of the squarylium dye according to the present disclosure, the dispersion according to the present disclosure, and the near-infrared absorbing composition according to the present disclosure include black matrices used in displays such as liquid crystal displays (LCDs) and plasma display panels (PDPs), curable compositions for producing these black matrices, color image recording materials for forming color images, ink compositions, heat ray shielding materials, heat ray absorbing materials, optical recording media, laser welding materials, laser marking materials, sensors (such as biometric authentication), etc. Specifically, sublimation type thermal recording materials, recording materials using an electrophotographic method (for example, color toners), transfer type silver halide photosensitive materials, printing inks, security inks, traceability inks, recording pens, dyeing of fibers, films for greenhouses, glasses, use in optical disks, etc. can be mentioned. In addition, sensors for biometric authentication (fingerprint authentication, vein authentication, etc.) are used for biometric authentication functions such as fingerprint authentication and finger vein authentication for security protection in smartphones, tablet computers, etc., as well as in bank ATMs, multimedia terminals, etc. Further, the biometric authentication sensor is preferably used for an in-display fingerprint authentication sensor in a smartphone, a tablet computer, or the like.

Example

[0219] Hereinafter, the present disclosure will be described in detail by way of examples, but the present disclosure is not limited thereto. In this example, “%” and “parts” mean “mass %” and “parts by mass”, respectively, unless otherwise specified. Note that B-1 to B-35 in the examples are the same compounds as B-1 to B-35 described above, respectively.

[0220] (Example 1)

[0221]

Chemical formula

[0222] Compound A-1 (38 g), squaric acid 15 g, toluene 650 ml, and butanol 240 ml were added, and the mixture was heated to reflux for 6 hours. At this time, under nitrogen flow conditions, a Dean-Stark tube was used to perform azeotropic dehydration of water. The reaction solution was cooled to room temperature (25 °C, the same hereinafter), and the generated precipitate was filtered and washed with ethyl acetate. Subsequently, 520 ml of dimethylformamide was cooled in another container to an internal temperature of 5 °C or lower, and then the precipitate obtained above was added, and the mixture was stirred at 5 °C or lower for 30 minutes. After completion of stirring, filtration was quickly performed, and the precipitate was washed with ethyl acetate. The obtained precipitate was returned to the original container, 390 ml of ethyl acetate was added, and the mixture was heated and dispersed. After allowing to cool, filtration was performed, the precipitate was washed with ethyl acetate, and dried by blowing air at 50 °C. 37.2 g of the target product was obtained. The area ratio of the peak corresponding to compound B-1 was 93%.

[0223] (Example 3)

[0224]

Chem.

[0225] Compound A-3 (10 g), squaric acid 3.4 g, toluene 160 ml, and isopropanol 30 ml were added, and the mixture was heated to reflux for 8 hours. At this time, under nitrogen flow conditions, a Dean-Stark tube was used to perform azeotropic dehydration of water. The reaction solution was cooled to room temperature, and the resulting precipitate was filtered and washed with ethyl acetate. Subsequently, 120 ml of dimethylformamide was cooled in a separate container to an internal temperature of 5°C or lower, and then the previously obtained precipitate was added, and the mixture was stirred at 5°C or lower for 30 minutes. After completion of stirring, it was quickly filtered, and the precipitate was washed with ethyl acetate. The obtained precipitate was returned to the original container, 120 ml of ethyl acetate was added, and the mixture was heated and dispersed. After allowing to cool, it was filtered, the precipitate was washed with ethyl acetate, and dried by blowing air at 50°C. 9.1 g of the target product was obtained. The area ratio of the peak corresponding to Compound B-3 was 95%.

[0226] (Example 8)

[0227]

Chem.

[0228] Compound A-22 (12 g), squaric acid 3.4 g, toluene 160 ml, and butanol 30 ml were added, and the mixture was heated to reflux for 8 hours. At this time, under nitrogen flow conditions, a Dean-Stark tube was used to perform azeotropic dehydration of water. The reaction solution was cooled to room temperature, and the resulting precipitate was filtered and washed with ethyl acetate. Subsequently, 120 ml of dimethylformamide was cooled in a separate container to an internal temperature of 5°C or lower, and then the previously obtained precipitate was added, and the mixture was stirred at 5°C or lower for 30 minutes. After completion of stirring, it was quickly filtered, and the precipitate was washed with ethyl acetate. The obtained precipitate was returned to the original container, 120 ml of ethyl acetate was added, and the mixture was heated and dispersed. After allowing to cool, it was filtered, the precipitate was washed with ethyl acetate, and dried by blowing air at 50°C. 9.5 g of the target product was obtained. The area ratio of the peak corresponding to Compound B-22 was 94%.

[0229] (Examples 2, 4 to 7, and 9 to 19) Squarylium dyes other than those described above were synthesized in the same manner as in Example 1, except that the starting materials were changed to substrates corresponding to the final products.

[0230] (Comparative Example 1: Synthesis of Low-Purity Form T-22 of B-22) Compound A-22 (54 g), squaric acid 15 g, toluene 650 ml, and butanol 240 ml were added, and the mixture was heated under reflux for 8 hours. At this time, while using a Dean-Stark tube under a nitrogen flow condition, water was azeotropically dehydrated. The reaction solution was cooled to room temperature, the resulting precipitate was filtered, washed with ethyl acetate, and 52 g of the target product was obtained. The area ratio of the peak corresponding to Compound B-22 was 88%.

[0231] ><Method for Measuring Peak Area Ratio Using High-Performance Liquid Chromatography (HPLC)> - Sample Preparation Method - 10 mg of the sample was weighed, made up to 20 ml with N-methylpyrrolidone (NMP), and dissolved by applying ultrasonic waves for 5 minutes while maintaining the liquid temperature at 10°C or lower. After filtering through a syringe filter, the measurement was performed immediately. - Measurement Conditions - Apparatus: Nexera X2 manufactured by Shimadzu Corporation Column: Kinetex C18 2.6 μm, 150 mm × 4.6 mm Flow rate: 1.0 ml / min Column temperature: 40°C Detection wavelength: 254 nm Mobile phase: ultrapure water / tetrahydrofuran (THF) / acetic acid = 50 / 50 / 0.1 (volume%)

[0232]

Table 1

[0233] In Table 1, DMF represents N,N-dimethylformamide, DMAc represents N,N-dimethylacetamide, NMP represents N-methylpyrrolidone, and DMSO represents dimethyl sulfoxide.

[0234] (Example C1) 90 mg of Compound B-1, 9 g of ultrapure water, and 60 mg of DisperBYK-191 (dispersant, manufactured by BYK) were added, and 9 g of zirconia beads with a diameter of Φ0.1 mm were added. Subsequently, the mixture was dispersed at 500 rpm for 6 hours using a planetary bead mill disperser. After the dispersion was completed, the beads were filtered to prepare Dispersion C-1 (dispersion). Dispersion C-1 was spin-coated on a glass substrate and then dried on a hot plate at 120 °C for 2 minutes to prepare a cured film.

[0235] (Examples C2 to C13 and Comparative Example C1) A dispersion was prepared and a cured film was prepared in the same manner as in Example C1, except that the compound obtained in Example 2 to 13 or Comparative Example 1 was used.

[0236] <Average particle size> The volume average particle size of the dispersion was measured using a Zetasizer NanoZS (manufactured by Malvern Panalytical).

[0237] <Heat resistance> After heating the obtained cured film at 210 °C for 5 minutes, the ΔEab value of the color difference before and after the heat resistance test was measured using a colorimeter MCPD-1000 (manufactured by Otsuka Electronics Co., Ltd.). A smaller ΔEab value indicates better heat resistance. Note that the ΔEab value is a value obtained from the following color difference formula in the CIE1976 (L * , a * , b * ) spatial color system (New Edition Color Science Handbook edited by the Color Science Society of Japan (1985), p. 266). ΔEab = {(ΔL * ) 2 + (Δa * ) 2 + (Δb * )2} 1 / 2 <<Judgment Criteria>> A: ΔEab value < 5 B: 5 ≤ ΔEab value < 20 C: 20 ≤ ΔEab value

[0238] <Light Resistance> For the obtained cured film, after irradiating light of 10,000 lux for 20 hours through an ultraviolet cut filter with a Xe lamp, the ΔEab value of the color difference before and after the light resistance test was measured with a colorimeter MCPD - 1000 (manufactured by Otsuka Electronics Co., Ltd.). <<Judgment Criteria>> A: ΔEab value < 5 B: 5 ≤ ΔEab value < 20 C: 20 ≤ ΔEab value

[0239] <Dispersion Stability> After allowing the obtained dispersion to stand at 25°C for one week, the particle size was measured again. A: The change rate is < 10% B: The change rate is 10% - 20% C: The change rate is > 20%

[0240] The evaluation results are shown in Table 2 below.

[0241]

Table 2

[0242] (Example C14) Except that DisperBYK - 191 was changed to DisperBYK - 190 (dispersant, manufactured by BYK), evaluation was carried out in the same manner as in Example C1. As a result, the average particle size was 242 nm, the dispersion stability was A, the heat resistance was A, and the light resistance was A.

[0243] (Example C15) Except that DisperBYK - 191 was changed to DisperBYK - 180 (dispersant, manufactured by BYK), evaluation was carried out in the same manner as in Example C1. As a result, the average particle size was 271 nm, the dispersion stability was A, the heat resistance was A, and the light resistance was A.

[0244] (Example C16) Except that DisperBYK-191 was changed to sodium dodecylbenzenesulfonate (an anionic surfactant), the evaluation was carried out in the same manner as in Example C1. As a result, the average particle size was 265 nm, the dispersion stability was A, the heat resistance was A, and the light resistance was A.

[0245] (Example C17) 100 mg of Compound B-3, 5 g of 3-methyl-1,5-pentanediol diacrylate (product name SR341, manufactured by Sartomer), and 100 mg of Biolin D-7240 (a nonionic surfactant, manufactured by Takemoto Yushi Co., Ltd.) were added, and 12 g of zirconia beads with a diameter of Φ0.1 mm were added. Subsequently, the mixture was dispersed at 500 rpm for 6 hours using a planetary bead mill disperser. After the dispersion was completed, the beads were filtered to prepare a dispersion liquid C-14 (dispersion). When evaluated in the same manner as in Example C1, the average particle size was 274 nm, the dispersion stability was A, the heat resistance was A, and the light resistance was A.

[0246] (Example 20) After Compound B-1 was synthesized in the same procedure as before, it was stirred using dimethylformamide and purified in the same manner except that the washing solvent after filtration was changed from ethyl acetate to methanol. The yield was 37.5 g, and the area ratio of the peak corresponding to Compound B-1 was 93%. In addition, except that the obtained Compound B-1 was used, a dispersion liquid was prepared in the same manner as in Example C1, and the heat resistance was evaluated. As a result, it was evaluated as A.

[0247] (Example 21) After Compound B-3 was synthesized in the same procedure as before, it was stirred using dimethylformamide and purified in the same manner except that the washing solvent after filtration was changed from ethyl acetate to acetone. The yield was 9.2 g, and the area ratio of the peak corresponding to Compound B-3 was 95%. In addition, except that the obtained Compound B-1 was used, a dispersion liquid was prepared in the same manner as in Example C1, and the heat resistance was evaluated. As a result, it was evaluated as A.

[0248] (Comparative Example 2) Compound A-3 (10 g), squaric acid 3.4 g, toluene 160 ml, and isopropanol 30 ml were added, and the mixture was heated under reflux for 8 hours. At this time, it was carried out while azeotropically dehydrating water using a Dean-Stark tube under nitrogen flow conditions. The reaction solution was cooled to room temperature, and the resulting precipitate was filtered and washed with ethyl acetate. Subsequently, 120 ml of dimethylformamide was heated to 40 °C in a separate container, and then the precipitate obtained above was added and stirred at 40 °C for 30 minutes. After completion of stirring, it was immediately filtered, and the precipitate was washed with ethyl acetate. The obtained precipitate was returned to the original container, 120 ml of ethyl acetate was added, and it was heated and dispersed. After allowing to cool, it was filtered, the precipitate was washed with ethyl acetate, and dried by blowing air at 50 °C. However, a large amount of impurities were generated, and the filtration became clogged, resulting in only a small amount of the target product being obtained. Also, a cured film could not be produced, and the heat resistance could not be evaluated.

[0249] (Comparative Example 3) In Comparative Example 2, when carried out in the same manner except that the temperature of dimethylformamide was 25 °C, although the target product was obtained in a yield of about 85%, a large amount of impurities were generated. Also, a cured film could not be produced, and the heat resistance could not be evaluated.

[0250] (Example 22) In Synthesis Example 2, when carried out in the same manner except that the temperature of dimethylformamide was 15 °C, 9.1 g of Compound B-3, which is the target product, was obtained. Also, the area ratio of the peak corresponding to Compound B-3 was 95%. Also, except using the obtained Compound B-3, a dispersion was prepared and the heat resistance was evaluated in the same manner as in Example 1, and the evaluation was Grade A.

[0251] (Example 101) (Preparation of Near-Infrared Absorbing Composition) The following composition was mixed to prepare a near-infrared absorbing composition. - Composition - Compound B-31: 1.2 parts Resin: Copolymer of allyl methacrylate (AMA) and methacrylic acid (MAA) (composition ratio (mass ratio): (AMA / MAA) = (80 / 20), Mw = 15,000): 14 parts Polymerizable compound: Dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd., product name KAYARAD DPHA): 12.9 parts Photoinitiator: IRGACURE - OXEO1 [2-(o-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione], manufactured by BASF: 2.5 parts Ultraviolet absorber: UV503 (Daito Chemical Co., Ltd.): 0.5 part Surfactant: The following mixture (Mw = 14000): 0.04 part Polymerization inhibitor: p-methoxyphenol: 0.006 part Cyclohexanone: 49.6 parts Propylene glycol monomethyl ether acetate: 19.3 parts

[0252]

Chemical formula

[0253] <Preparation of cured film> The obtained composition was applied onto a glass substrate (Corning 1737) using a spin coater so that the film thickness after drying would be 1.0 μm, and heat treatment (pre-bake) was performed for 120 seconds using a hot plate at 100°C. Next, using an i-line stepper exposure apparatus FPA - 3000i5+ (manufactured by Canon Inc.), full surface exposure was performed at 500 mJ / cm 2 Then paddle development was carried out at 23°C for 60 seconds using a developing machine (CD - 2060, manufactured by Fujifilm Electronic Materials Co., Ltd.), then rinsing treatment was performed with pure water, and then spray drying was carried out. Further, heat treatment (post-bake) was performed for 300 seconds using a hot plate at 200°C to obtain a cured film. As a result of evaluating the heat resistance and light resistance of the obtained cured film, both were rated A.

Claims

1. Comprising at least one of a compound represented by the following formula (1) and its isomers, The purity measured at a detection wavelength of 254 nm using high performance liquid chromatography is 90% or more with respect to the peak areas of all peaks excluding the peaks derived from the measurement solvent, for the peak areas of the compound represented by the formula (1) and its isomers. A squarylium dye. 【Chemical 1】 In formula (1), R １ and R ２ each independently represent an alkyl group, an alkenyl group, an aryl group or a heteroaryl group, R ３ and R ４ each independently represents a hydrogen atom or an alkyl group, X １ and X ２ each independently represents an oxygen atom or -N(R ５ ), R ５ represents a hydrogen atom, an alkyl group, an aryl group or a heteroaryl group, Y １ ~Y ４ each independently represents a halogen atom or a monovalent organic group, and Y １ and Y ２ , and, Y ３ and Y ４ may be bonded to each other to form a ring structure, Y １ ~Y ４ When there are a plurality of each of them, the plurality of Ys １ among themselves, the plurality of Ys ２ among themselves, the plurality of Ys ３ among themselves or the plurality of Ys ４ among themselves may be bonded to each other to form a ring structure, p and s each independently represent an integer from 0 to 3, q and r each independently represent an integer from 0 to 2.

2. R ３ and R ４ are hydrogen atoms, and X １ and X ２ is NH, the squarylium dye according to Claim 1.

3. R １ and R ２ The squarylium dye according to claim 1 or claim 2, wherein are the same group.

4. The squarylium dye according to claim 1 or claim 2, which is in the form of particles.

5. A dispersion comprising the squarylium dye according to claim 1 or claim 2 and a resin.

6. A near-infrared absorbing composition comprising the squarylium dye according to claim 1 or claim 2.

7. A step of preparing at least one crude product of the compound represented by the formula (1) and its isomers, A step of stirring the crude product in an organic polar solvent at 20°C or lower, and A method for purifying the squarylium dye according to claim 1 or claim 2, comprising a step of filtering the stirred mixture after the stirring.

8. The method for purifying the squarylium dye according to claim 7, wherein the organic polar solvent is an amide-based solvent.

9. The method for purifying the squarylium dye according to claim 7, wherein the temperature of the organic polar solvent in the stirring step is 10°C or lower.

10. The method for purifying the squarylium dye according to claim 7, comprising a step of mixing the filtrate with an ester-based solvent after the filtering step, heating the mixture to 50°C to the boiling point of the ester-based solvent, and filtering the heated mixture after the heating.

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