Squarylium compound

Abstract

Provided is a squarylium compound represented by formula (1). [In formula (1), R11 and R21 each represent an alkyl group or an aralkyl group, R12, R13, R22, and R23 each represent a hydrogen atom or an alkyl group, R14 and R24 each represent a C26-C35 branched alkyl group, a group represented by formula (2), or a group represented by formula (3), and ring A1 and ring A2 each represent a nitrogen-containing heterocyclic ring.] [In formulae (2) and (3), R31 includes a group represented by -C(=O)-R34, a group represented by -SO2-R35, or a group represented by -SiR36R37R38, ring B represents a hydrocarbon ring, and at least one of R32 to R38 is a C12 or higher, linear alkyl group, an aryl group, or an aralkyl group.]

Description

Squarylium Compounds

[0001] The present disclosure relates to a squarylium compound, a resin composition containing the squarylium compound, and a molded article and optical filter formed from the resin composition.

[0002] Squarylium compounds are useful as dyes having an absorption range in the red to near-infrared region, and the present applicant has filed patent applications relating to various squarylium compounds. For example, Patent Documents 1 to 4 disclose squarylium compounds having a structure in which pyrrole rings are bonded to both sides of a squarylium skeleton via carbon atoms, and Patent Document 5 discloses a squarylium compound having a structure in which benzene rings are bonded to both sides of a squarylium skeleton.

[0003] JP 2016-074649 A JP 2017-067963 A WO 2017 / 146187 JP 2018-095798 A JP 2019-031637 A

[0004] Taking advantage of their absorption range in the red to near-infrared region, squarylium compounds are expected to be used in near-infrared cut filters, near-infrared absorbing films, security inks, and the like. Because squarylium compounds generally have low solubility in organic solvents, when squarylium compounds are used for such purposes, it is desirable to handle the squarylium compounds by dissolving them in an organic solvent, thereby improving the handleability of the squarylium compounds. Examples of squarylium compounds with excellent solubility in organic solvents include the squarylium compounds disclosed in Patent Document 5. However, when the present applicant dissolved the squarylium compound disclosed in Patent Document 5 in an organic solvent to prepare a squarylium compound solution and stored it at a low temperature of −20°C, it was found that the squarylium compound solution solidified (see FIG. 3 ). This phenomenon differs from the precipitation of the squarylium compound from the squarylium compound solution, and also differs from the usual phase change from liquid to solid upon cooling, since the storage temperature of −20°C is much higher than the melting point of the solvent, resulting in a partial gel state rather than simple solidification.

[0005] In view of the above circumstances, an object of the present disclosure is to provide a squarylium compound having a structure in which benzene rings are bonded to both sides of a squarylium skeleton, which can prevent the solution from solidifying when dissolved in an organic solvent to form a squarylium compound solution and stored at a low temperature (but higher than the melting point of the solvent).

[0006] The squarylium compound according to the present disclosure that can solve the above problems is as follows: [1] A squarylium compound represented by the following formula (1): [In formula (1), R １１ and R ２１ each independently represents an alkyl group which may have a substituent or an aralkyl group which may have a substituent; R １２ , R １３ , R ２２ and R ２３ each independently represents a hydrogen atom or an alkyl group; R １４ and R ２４ each independently represents a branched alkyl group having 26 to 35 carbon atoms which may have a substituent, a group represented by the following formula (2), or a group represented by the following formula (3); １ and Ring A ２ each independently represents a 5- to 8-membered nitrogen-containing heterocycle, and the nitrogen-containing heterocycle is １１ and R ２１ may have a substituent other than the above.] [In formula (2), R ３１ is -C(=O)-R ３４ an acyl group represented by —SO ２ -R ３５ or a sulfonyl group-containing group represented by —Si(R ３６ ) (R ３７ ) (R ３８ ) and R ３４ ~R ３８ each independently represents an alkyl group which may have a substituent, an aryl group which may have a substituent, or an aralkyl group which may have a substituent; R ３２ and R ３３each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted aralkyl group; R ３２ ~R ３８ at least one of R is an optionally substituted linear alkyl group having 12 or more carbon atoms, an optionally substituted aryl group, or an optionally substituted aralkyl group; ３１ represents the same meaning as above; Ring B represents a hydrocarbon ring which may have a substituent and / or a fused ring structure; R ３４ ~R ３８ At least one of the R is a linear alkyl group having 12 or more carbon atoms which may have a substituent, an aryl group which may have a substituent, or an aralkyl group which may have a substituent. １４ and R ２４ is a branched alkyl group having 26 to 35 carbon atoms which may have a substituent, and the branched alkyl group is branched at the carbon atom at the α-position. ３２ represents an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted aralkyl group. １４ and R ２４ is a group represented by the formula (2), and ３１ contains the acyl group, and the R ３２ ~R ３４ At least one of R is a linear alkyl having 12 or more carbon atoms which may have a substituent, or １４ and R ２４ is a group represented by the formula (3), and ３１ contains the acyl group, and the R ３４ [5] The squarylium compound according to [1] or [3], wherein R is a linear alkyl having 12 or more carbon atoms which may have a substituent. １４ and R ２４ is a group represented by the formula (2), and ３１ contains the sulfonyl group-containing group, and the R ３２ , R３３ and R ３５ At least one of R is a linear alkyl having 12 or more carbon atoms which may have a substituent, or １４ and R ２４ is a group represented by the formula (3), and ３１ contains the sulfonyl group-containing group, and the R ３５ [6] The squarylium compound according to [1] or [3], wherein R is a linear alkyl having 12 or more carbon atoms which may have a substituent. １４ and R ２４ is a group represented by the formula (2), and ３１ contains the silyl group, and the R ３２ , R ３３ and R ３６ ~R ３８ two or more of R are aryl groups which may have a substituent, or １４ and R ２４ is a group represented by the formula (3), and ３１ contains the silyl group, and the R ３６ ~R ３８ The squarylium compound according to [1] or [3], wherein at least one of the groups is an aryl group which may have a substituent.

[0007] The present disclosure also provides the following resin composition, molded article, and optical filter. [7] A resin composition containing the scrillium compound according to any one of [1] to [6] and a resin component. [8] A molded article formed from the resin composition according to [7]. [9] An optical filter having a resin layer formed from the resin composition according to [7].

[0008] When the squarylium compound according to the present disclosure is dissolved in an organic solvent to form a squarylium compound solution and stored at low temperature, solidification of the solution can be suppressed.

[0009] 1 shows a transmission spectrum of an optical filter formed from resin composition 2 examined in the examples. 2 shows a transmission spectrum of an optical filter formed from resin composition 4 examined in the examples. 3 shows a photograph of the appearance of a toluene solution of a squarylium compound of Patent Document 5, which has solidified when the solution is stored at low temperature. 4 shows a photograph of the appearance of a toluene solution of a squarylium compound that does not solidify when stored at low temperature in the examples.

[0010] The squarylium compound according to the present disclosure is represented by the following formula (1): １１ and R ２１ each independently represents an alkyl group which may have a substituent or an aralkyl group which may have a substituent; R １２ , R １３ , R ２２ and R ２３ each independently represents a hydrogen atom or an alkyl group, R １４ and R ２４ each independently represents a branched alkyl group having 26 to 35 carbon atoms which may have a substituent, a group represented by the following formula (2), or a group represented by the following formula (3), and ring A １ and Ring A ２ each independently represents a 5- to 8-membered nitrogen-containing heterocycle, and the nitrogen-containing heterocycle is １１ and R ２１ In addition, it may have a substituent.

[0011]

[0012]

[0013] In formula (2), R ３１ is -C(=O)-R ３４ an acyl group represented by —SO ２ -R ３５ or a sulfonyl group-containing group represented by —Si(R ３６ ) (R ３７ ) (R ３８ ) and R ３４ ~R ３８each independently represents an alkyl group which may have a substituent, an aryl group which may have a substituent, or an aralkyl group which may have a substituent; R ３２ and R ３３ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted aralkyl group; R ３２ ~R ３８ At least one of the groups is an optionally substituted linear alkyl group having 12 or more carbon atoms, an optionally substituted aryl group, or an optionally substituted aralkyl group.

[0014] In formula (3), R ３１ represents the same meaning as above, ring B represents a hydrocarbon ring which may have a substituent and / or a fused ring structure, R ３４ ~R ３８ At least one of the groups is an optionally substituted linear alkyl group having 12 or more carbon atoms, an optionally substituted aryl group, or an optionally substituted aralkyl group.

[0015] Squarylium compounds may have compounds that have a resonance relationship with them. Examples of compounds that have a resonance relationship with the squarylium compound of formula (1) include compounds represented by the following formulas (1a) and (1b). The squarylium compounds according to the present disclosure include all of these compounds that have a resonance relationship.

[0016]

[0017] In formula (1), the groups bonded to one side and the other side of the squarylium skeleton may be the same or different. １１ , R １２ , R １３ , R １４ and Ring A １ are R ２１ , R ２２ , R ２３ , R ２４ and Ring A ２When the groups bonded to one side and the other side of the squarylium skeleton are the same, the squarylium compound is expected to have improved durability against heat and light. When the groups bonded to one side and the other side of the squarylium skeleton are different, association and aggregation between molecules of the squarylium compound is suppressed, and improved solubility in organic solvents and resins is expected.

[0018] The squarylium compound represented by formula (1) can prevent the solution from solidifying when it is dissolved in an organic solvent to form a squarylium compound solution and stored at low temperature. The squarylium compound represented by formula (1) is similar to the squarylium compound disclosed in Patent Document 5, but the squarylium compound in Patent Document 5 has a structure similar to that of the squarylium compound represented by formula (1) except that the squarylium compound in Patent Document 5 has a structure similar to that of the squarylium compound represented by formula (1) but not R １４ and R ２４ is a linear alkyl group having 5 or more carbon atoms. The squarylium compound of Patent Document 5 has excellent solubility in organic solvents, but when a squarylium compound solution in which the squarylium compound is dissolved in an organic solvent is stored at low temperature, the squarylium compound solution may solidify. In contrast, the squarylium compound represented by formula (1) has １１ and R ２１ is an alkyl group or an aralkyl group, and R １４ and R ２４ is a branched alkyl group having from 26 to 35 carbon atoms, a group represented by the above formula (2), or a group represented by the above formula (3), solidification of the squarylium compound solution can be prevented when the squarylium compound solution is dissolved in an organic solvent and stored at low temperature.

[0019] In the examples described below, it was confirmed that when the squarylium compound of Patent Document 5 (Comparative Squaryllium Compound 1) was dissolved in toluene to form a toluene solution of the squarylium compound, the solution solidified. Although the mechanism of this solidification is not entirely clear, it is believed to be due to the squarylium compound of Patent Document 5 having a structure in which relatively long-chain linear alkyl groups extend via amide groups from a highly planar aromatic unit (a structural unit in which benzene rings are bonded to both sides of a squarylium skeleton). When such a squarylium compound is dissolved in toluene, the linear alkyl groups attract each other through intermolecular forces, forming a mesh-like network, and the aromatic units and toluene associate through π-π stacking. When this is cooled, it solidifies in a state in which toluene is contained within the mesh structure formed by the relatively long-chain linear alkyl groups, and the toluene solution of the squarylium compound is believed to solidify.

[0020] In formula (1), R １１ and R ２１ each independently represents an alkyl group which may have a substituent, or an aralkyl group which may have a substituent. The squarylium compound of formula (1) can be １１ and R ２１ When is an alkyl group or an aralkyl group, the solubility in organic solvents and resins can be increased.

[0021] R １１ and R ２１Examples of the alkyl group include linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl; and cyclic (alicyclic) alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl. The alkyl group may have a substituent, and examples of the substituent on the alkyl group include an aryl group, a heteroaryl group, a halogeno group, an alkoxy group, a cyano group, a nitro group, and an amino group. Examples of alkyl groups having a halogeno group include monohalogenoalkyl groups, dihalogenoalkyl groups, alkyl groups having a trihalomethyl unit, and perhalogenoalkyl groups. As the halogeno group, a fluorine atom, a chlorine atom, or a bromine atom is preferred, with a fluorine atom being particularly preferred. The number of carbon atoms in the alkyl group (the number of carbon atoms excluding substituents) is preferably 1 to 20. Specifically, if the alkyl group is a linear or branched alkyl group, the number of carbon atoms is preferably 1 to 22, more preferably 1 to 12, even more preferably 1 to 8, and even more preferably 1 to 6; if the alkyl group is a cyclic alkyl group, the number of carbon atoms is preferably 4 to 10, more preferably 5 to 8.

[0022] R １１ and R ２１ The alkyl group in R is preferably branched. This effectively increases the solubility of the squarylium compound in organic solvents and resins. １１ and R ２１ The number of carbon atoms in the alkyl group (excluding the number of carbon atoms in the substituent) is 3 or more. １１ and R ２１ Examples of the branched alkyl group include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a sec-pentyl group, a 1-ethylpropyl group, a neopentyl group, a tert-pentyl group, an isohexyl group, a sec-hexyl group, a 2-methylpentyl group, a 3-methylpentyl group, a tert-hexyl group, and a 2-ethylhexyl group.

[0023] R １１ and R ２１ Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a phenylbutyl group, a phenylpentyl group, and a naphthylmethyl group. The aralkyl group may have a substituent, and examples of the substituent that the aralkyl group has include an alkyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, a halogeno group, a halogenoalkyl group, a cyano group, a nitro group, a thiocyanate group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an aralkyloxycarbonyl group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, and a sulfamoyl group. The number of carbon atoms in the aralkyl group (the number of carbon atoms excluding the substituent) is preferably 7 to 25, and more preferably 7 to 15. The ring A contained in the aralkyl group １ or ring A ２ The alkylene group bonded to the nitrogen atom preferably has 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms, and even more preferably 1 or 2 carbon atoms.

[0024] In formula (1), R １２ , R １３ , R ２２ and R ２３ R each independently represents a hydrogen atom or an alkyl group. １２ , R １３ , R ２２ and R ２３ The details of the alkyl group of R １１ and R ２１ The description of alkyl groups is given in R １２ , R １３ , R ２２ and R ２３ is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom.

[0025] In formula (1), R １４ and R ２４each independently represents [1] a branched alkyl group having 26 to 35 carbon atoms which may have a substituent, [2] a group represented by the above formula (2), or [3] a group represented by the above formula (3). The squarylium compound disclosed in Patent Document 5 is １４ and R ２４ is a linear alkyl group having 5 or more carbon atoms, but this can be changed to a branched alkyl group having a larger number of carbon atoms, or R １４ and R ２４ By incorporating an acyl group, a sulfonyl group-containing group, or a silyl group into the compound, solidification of the squarylium compound solution can be suppressed even when the solution is stored at low temperatures, and the solubility of the squarylium compound in organic solvents and resins can be easily ensured.

[0026] R １４ and R ２４ [1] In the case of a branched alkyl group having 26 to 35 carbon atoms, the number of carbon atoms in the branched alkyl group is preferably 28 or more, more preferably 30 or more, and preferably 34 or less. When the branched alkyl group has a substituent, the number of carbon atoms in the branched alkyl group means the number of carbon atoms excluding the substituent. The number of branching points in the carbon chain of the branched alkyl group is not particularly limited as long as it is 1 or more, and may be 2 or more or 3 or more. The upper limit of the number of branching points is not particularly limited, and may be, for example, 10 or less, 8 or less, or 6 or less. The number of carbon chains branching at one branching point may be 2 or 3. The branching points in the carbon chain of the branched alkyl group are R １４ or R ２４ may be a carbon atom at the α-position relative to the amide group to which the carbon atom is bonded (the carbon atom adjacent to the amide group), may be a carbon atom at the β-position, may be a carbon atom at the γ-position, or may be a carbon atom further away from these.

[0027] R １４ and R ２４ The branched alkyl group may have a substituent, and examples of the substituent include an aryl group, a heteroaryl group, a halogeno group, a cyano group, a nitro group, and an amino group. １４ and R ２４The branched alkyl group preferably has no substituent.

[0028] R １４ and R ２４ The number of branching points of the branched alkyl group of R is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. １４ and R ２４ The branched alkyl group is preferably branched at a carbon atom at the α-position to the γ-position, more preferably at the α-position or the β-position, and even more preferably at the α-position, which allows the branched alkyl group to have a longer chain.

[0029] R １４ and R ２４ In the branched alkyl group of R, the alkyl group at the branching point is preferably a linear alkyl group having 8 or more carbon atoms, more preferably 10 or more carbon atoms, even more preferably 12 or more carbon atoms, and even more preferably 14 or more carbon atoms, and preferably 22 or less carbon atoms, more preferably 20 or less carbon atoms, and even more preferably 18 or less carbon atoms. １４ and R ２４ In the branched alkyl group of R, each alkyl group at the branching point is preferably such a linear alkyl group. １４ and R ２４ If the alkyl group is such a branched alkyl group, the squarylium compound solution can be more effectively prevented from solidifying when stored at low temperature.

[0030] R １４ and R ２４ When R is a branched alkyl group, １４ and R ２４ is preferably a group represented by the following formula (4): ４１ and R ４２ each independently represents a linear alkyl group having 8 to 22 carbon atoms; R ４３ represents a hydrogen atom or a linear alkyl group having 8 to 22 carbon atoms. ４３ is preferably a hydrogen atom, and R ４１ and R ４２The linear alkyl group preferably has 10 or more carbon atoms, more preferably 12 or more carbon atoms, and preferably has 20 or less carbon atoms, more preferably 18 or less carbon atoms.

[0031]

[0032] R １４ and R ２４ is a group represented by formula (2), R ３１ is -C(=O)-R ３４ an acyl group represented by —SO ２ -R ３５ or a sulfonyl group-containing group represented by —Si(R ３６ ) (R ３７ ) (R ３８ ) and R ３４ ~R ３８ each independently represents an alkyl group which may have a substituent, an aryl group which may have a substituent, or an aralkyl group which may have a substituent; R ３４ ~R ３８ The details of the alkyl group and aralkyl group are as described above for R １１ and R ２１ The explanation of alkyl groups and aralkyl groups is referred to. ３４ ~R ３８ The alkyl group in R is preferably a linear or branched alkyl group. ３４ ~R ３８ The alkyl group preferably has 1 to 22 carbon atoms, more preferably 2 to 20 carbon atoms, and even more preferably 3 to 18 carbon atoms.

[0033]

[0034] R ３４ ~R ３８Examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a pyrenyl group, and an indenyl group. The aryl group may have a substituent, and examples of the substituent that the aryl group has include an alkyl group, an alkoxy group, a heteroaryl group, a halogeno group, a halogenoalkyl group, a cyano group, a nitro group, an amino group, a thiocyanate group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, and a sulfamoyl group. The number of carbon atoms in the aryl group (the number of carbon atoms excluding the substituent) is preferably 6 to 20, and more preferably 6 to 12.

[0035] R ３１ The acyl group, sulfonyl group-containing group, and silyl group contained in R are preferably an acyloxy group, a sulfonyloxy group-containing group, and a silyloxy group, respectively. ３１ preferably contains an acyloxy group represented by the following formula (5), a sulfonyloxy group-containing group represented by the following formula (6), or a silyloxy group represented by the following formula (7). ３１ This makes it easy to introduce an acyl group, a sulfonyl group-containing group, or a silyl group into the

[0036]

[0037] The acyloxy group represented by formula (5), the sulfonyloxy group-containing group represented by formula (6), and the silyloxy group represented by formula (7) are R ３２ and R ３３ In the latter case, the acyloxy group, sulfonyloxy group-containing group, or silyloxy group is bonded to the carbon atom to which R in formula (2) is bonded via an alkylene group having 1 to 5 carbon atoms. ３２ and R ３３ The alkylene group preferably has 1 to 3 carbon atoms, and more preferably 1 or 2 carbon atoms. The alkylene group may have a substituent, and examples of the substituent include an aryl group, an aralkyl group, a heteroaryl group, and a halogeno group.

[0038] R ３１ When contains an acyl group, R ３４ is preferably an alkyl group or an aralkyl group, and more preferably an alkyl group. ３１ When R contains a sulfonyl group-containing group, R ３５ is preferably an aryl group or an aralkyl group, and more preferably an aryl group. ３１ When contains a silyl group, R contained in the silyl group ３６ ~R ３８ Preferably, at least one of the groups is an alkyl group and at least one of the groups is an aryl group or an aralkyl group.

[0039] R in formula (2) ３２ and R ３３ The details of the alkyl group, aryl group and aralkyl group are as described above for R ３４ ~R ３８ The alkyl group, aryl group, and aralkyl group may have a substituent. ３２ and R ３３ and are preferably not both hydrogen atoms, and therefore, at least R ３２ is preferably an alkyl group, an aryl group or an aralkyl group.

[0040] R ３２ and R ３３ The number of carbon atoms in the alkyl group of R may be 8 or more, 10 or more, or 12 or more, and may be 20 or less, or 18 or less. ３２ and R ３３ and R are preferably not alkyl groups having 8 or more carbon atoms. ３２ and R ３３ When one of R is an alkyl group having 8 or more carbon atoms, ３２ and R ３３ The other is preferably a hydrogen atom.

[0041] R ３２ and R ３３ When one of R is an aryl group or an aralkyl group, R ３２ and R ３３The other is preferably a hydrogen atom, an aryl group, or an aralkyl group.

[0042] In formula (2), R ３２ ~R ３８ At least one of R is a linear alkyl group having 12 or more carbon atoms (meaning the number of carbon atoms excluding substituents, the number of carbon atoms is preferably 13 or more, more preferably 14 or more, and preferably 22 or less, more preferably 20 or less, even more preferably 18 or less, and even more preferably 16 or less), which may have a substituent, an aryl group, or an aralkyl group which may have a substituent. ３２ ~R ３８ When at least one of the groups is such a group, the squarylium compound solution is prevented from solidifying when stored at low temperature.

[0043] In formula (2), R ３１ When R contains an acyl group, ３２ ~R ３４ At least one of R is preferably a linear alkyl having 12 or more carbon atoms which may have a substituent, ３２ and R ３４ at least one of R is a linear alkyl having 12 or more carbon atoms which may have a substituent; ３３ is more preferably a hydrogen atom, an aryl group which may have a substituent, or an aralkyl group which may have a substituent.

[0044] In formula (2), R ３１ When R contains a sulfonyl group-containing group, ３２ , R ３３ and R ３５ At least one of R is preferably a linear alkyl having 12 or more carbon atoms which may have a substituent, ３２ and R ３５ at least one of R is a linear alkyl having 12 or more carbon atoms which may have a substituent; ３３ is more preferably a hydrogen atom, an optionally substituted aryl group, or an optionally substituted aralkyl group, and R ３２ and R ３５one of R is a linear alkyl group having 12 or more carbon atoms which may have a substituent, ３２ and R ３５ the other is an optionally substituted aryl group or an optionally substituted aralkyl group, and R ３３ It is more preferred that is a hydrogen atom.

[0045] In formula (2), R ３１ When R contains a silyl group, ３２ , R ３３ and R ３６ ~R ３８ Preferably, two or more of R are optionally substituted aryl groups, ３２ and R ３３ at least one of R is an aryl group which may have a substituent; ３６ ~R ３８ It is more preferable that at least one of R is an aryl group which may have a substituent. ３２ and R ３３ is an aryl group which may have a substituent, and R ３２ and R ３３ the other is a hydrogen atom or an alkyl group, and R ３６ ~R ３８ one or two of R are optionally substituted aryl groups, ３６ ~R ３８ It is more preferred that the remainder of R is an alkyl group. ３６ ~R ３８ The remaining alkyl groups preferably have 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 2 to 5 carbon atoms.

[0046] R １４ and R ２４ is a group represented by formula (3), R ３１ is -C(=O)-R ３４ an acyl group represented by —SO ２ -R ３５ or a sulfonyl group-containing group represented by —Si(R ３６ ) (R ３７ ) (R ３８ ) and R ３４ ~R ３８each independently represents an alkyl group which may have a substituent, an aryl group which may have a substituent, or an aralkyl group which may have a substituent, and R in formula (3) ３１ The details of R in the above formula (2) ３１ Reference is made to the explanation regarding

[0047]

[0048] Ring B represents a hydrocarbon ring which may have a substituent and / or a fused ring structure. Examples of the hydrocarbon ring of Ring B include aliphatic hydrocarbon rings, such as monocyclic cycloalkanes having 3 to 10 carbon atoms, such as cyclopentane, cyclohexane, and cycloheptane; and monocyclic cycloalkenes having 3 to 10 carbon atoms, such as cyclopentene, cyclopentadiene, cyclohexene, cyclohexadiene (e.g., 1,3-cyclohexadiene), cycloheptene, and cycloheptadiene. The hydrocarbon ring of Ring B may have a fused ring structure fused with another ring, and examples of such ring structures of Ring B include an indene ring, a naphthalene ring, an anthracene ring, a fluorene ring, a benzofluorene ring, an indole ring, an isoindole ring, a benzimidazole ring, a quinoline ring, a benzopyran ring, an acridine ring, a xanthene ring, a carbazole ring, a purine ring, and a pteridine ring. When the squarylium compound has ring B, molecular distortion of the squarylium compound is more likely to occur, and association and aggregation of the squarylium compound are suppressed.

[0049] Ring B may have a substituent, and examples of the substituent include an alkyl group, an alkoxy group, an alkylthio group, an alkoxycarbonyl group, an aryl group, an aryloxycarbonyl group, a halogeno group, and a halogenoalkyl group. The alkyl group and the alkyl group contained in the alkoxy group, alkylthio group, alkoxycarbonyl group, and halogenoalkyl group are preferably linear or branched alkyl groups. In this case, the alkyl group, alkoxy group, alkylthio group, and halogenoalkyl group preferably have 1 to 8 carbon atoms, more preferably 1 to 6, and even more preferably 1 to 4 carbon atoms; the alkoxycarbonyl group preferably has 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms; and the aryl group and aryloxycarbonyl group preferably have 6 to 12 carbon atoms, more preferably 6 to 10 carbon atoms. Ring B may not have a substituent. When Ring B has a substituent, the number of substituents is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 to 2. When Ring B has multiple substituents, the multiple substituents may be the same or different.

[0050] The number of ring members in ring B is not particularly limited, but R ３１ The hydrocarbon ring to which the is bonded preferably has 5 to 8 ring members, more preferably 5 to 7 ring members, and even more preferably 5 or 6 ring members.

[0051] The hydrocarbon ring of ring B preferably has a π bond. This makes it easier for ring B to assume a distorted configuration with respect to the main plane of the squarylium, thereby increasing the molecular distortion of the squarylium compound. In this case, in ring B, R ３１ Preferably, the atom one atom away from the carbon to which the ring B is bonded is connected to the atom two atoms away from the carbon to which the ring B is bonded by a π bond. An example of the π bond is a double bond between carbon atoms. Ring B preferably has a fused ring structure fused with a hydrocarbon ring having a π bond, and examples of such ring structures include an indene ring, a naphthalene ring, an anthracene ring, a pentalene ring, an azulene ring, a fluorene ring, and a benzofluorene ring.

[0052] In formula (3), R ３４ ~R ３８At least one of R is a linear alkyl group having 12 or more carbon atoms (meaning the number of carbon atoms excluding substituents, the number of carbon atoms is preferably 13 or more, more preferably 14 or more, and preferably 22 or less, more preferably 20 or less, even more preferably 18 or less, and even more preferably 16 or less), which may have a substituent, an aryl group, or an aralkyl group which may have a substituent. ３４ ~R ３８ When at least one of the groups is such a group, the squarylium compound solution can be prevented from solidifying when stored at low temperature.

[0053] In formula (3), R ３１ When R contains an acyl group, ３４ is preferably a linear alkyl having 12 or more carbon atoms which may have a substituent. ３１ When R contains a sulfonyl group-containing group, ３５ is preferably a linear alkyl having 12 or more carbon atoms which may have a substituent. ３１ When R contains a silyl group, ３６ ~R ３８ Preferably, at least one of R is an aryl group which may have a substituent, ３６ ~R ３８ one or two of R are optionally substituted aryl groups, ３６ ~R ３８ The remainder is preferably an alkyl group. The alkyl group preferably has 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 2 to 5 carbon atoms.

[0054] Ring A of formula (1) １ and Ring A ２ each independently represents a 5- to 8-membered nitrogen-containing heterocycle. １ and Ring A ２ The nitrogen-containing heterocycle is ring A １ or ring A ２ is a heterocyclic ring in which a nitrogen atom is bonded to the carbon atom at the para-position relative to the bonding position of the squarylium skeleton of the fused benzene ring. １ and Ring A ２When ring A is formed from such a nitrogen-containing heterocycle, the maximum absorption peak of the squarylium compound shifts to the longer wavelength side (for example, 685 nm or more), increasing the transmittance of light in the red region and making it easier to make the color of the transmitted light closer to the actual color. １ and Ring A ２ The nitrogen-containing heterocycle of １ or ring A ２ The nitrogen atom bonded to the carbon atom at the para-position relative to the bonding position of the squarylium skeleton of the benzene ring to which the substituent R １１ or R ２１ is bonded, and the nitrogen-containing heterocycle is R １１ and R ２１ In addition to the ring A, the ring A may have a substituent. １ and Ring A ２ is preferably a non-aromatic nitrogen-containing heterocycle.

[0055] Ring A １ and Ring A ２ The nitrogen-containing heterocycle may have only one nitrogen atom as a heteroatom constituting the ring, or may have two or more heteroatoms. When having two or more heteroatoms, it must have at least one nitrogen atom and further have one or more atoms of at least one kind selected from N (nitrogen atom), S (sulfur atom), and O (oxygen atom). １ and Ring A ２ Examples of the nitrogen-containing heterocyclic ring include a pyrrolidine ring, a piperidine ring, a hexamethyleneimine ring, a heptamethyleneimine ring, a morpholine ring, a thiomorpholine ring, and a piperazine ring. １ and Ring A ２ The nitrogen-containing heterocycle preferably has only one nitrogen atom as a heteroatom. １ and Ring A ２ The nitrogen atom bonded to the carbon atom at the para-position to the bonding position of the squarylium skeleton of the benzene ring to which is fused is not included in Ring A. １ and Ring A ２ It is preferable that the carbon atoms of ring A are linked to form a ring. １ and Ring A ２is preferably a ring formed by bonding a carbon atom to a nitrogen atom or bonding carbon atoms together via a single bond, except for the carbon-carbon bond condensed with the benzene ring.

[0056] Ring A １ and Ring A ２ The nitrogen-containing heterocycle is R １１ and R ２１ In other words, ring A may have a substituent. １ and Ring A ２ The nitrogen-containing heterocycle is ring A １ or ring A ２ A substituent may be bonded to a ring-constituting atom other than the nitrogen atom bonded to the carbon atom at the para-position relative to the bonding position of the squarylium skeleton of the benzene ring to which the ring is fused. Examples of the substituent include an alkyl group, an alkoxy group, an aryl group, an aralkyl group, a halogeno group, a halogenoalkyl group, etc., with an alkyl group, an aryl group, an aralkyl group, and a halogenoalkyl group being more preferred. In this case, the alkyl group, alkoxy group, and halogenoalkyl group preferably have 1 to 8 carbon atoms, more preferably 1 to 5, and even more preferably 1 to 3 carbon atoms, the aryl group preferably has 6 to 12 carbon atoms, more preferably 6 to 10 carbon atoms, and the aralkyl group preferably has 7 to 13 carbon atoms, more preferably 7 to 11 carbon atoms. The alkyl group may be linear or branched. In addition, in the case of ring A, １ and Ring A ２ is R １１ and R ２１ It may not have any other substituents.

[0057] Ring A １ and Ring A ２ The number of ring members of ring A is 5 or more and 8 or less, preferably 6 or more and 7 or less. １ and Ring A ２ If the number of ring members is 6 or more, the absorption peak having the maximum absorption in the red to near-infrared region can be made sharp, and the slope of the slope on the short wavelength side of the absorption peak can be made to be absorbing. Therefore, the boundary between the transmission wavelength region and the absorption wavelength region is formed sharply, and it becomes possible to selectively cut off light in the wavelength region corresponding to the absorption peak.

[0058] Ring A described above １ and Ring A２ Regarding the constitution of (1), a preferred squarylium compound is a squarylium compound represented by the following formula (8):

[0059]

[0060] In formula (8), R １１ ~R １４ , R ２１ ~R ２４ is as explained above. １５ is ring A １ represents a hydrogen atom or a substituent bonded to a carbon atom constituting R ２５ is ring A ２ represents a hydrogen atom or a substituent bonded to a carbon atom constituting the group, and m and n represent integers of 1 to 4 (preferably integers of 1 to 3, more preferably 2 or 3). １５ may be the same or different, and multiple R ２５ may be the same or different. The squarylium compound of formula (8) is １ and Ring A ２ However, it is a 5- to 8-membered heterocyclic ring with only one nitrogen atom as the heteroatom, and except for the carbon-carbon bond condensed with the benzene ring, the carbon atoms are bonded to the nitrogen atom or to each other by single bonds to form the ring.

[0061] R １５ and R ２５ are each independently preferably a group or atom selected from the group consisting of a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, a halogeno group, and a halogenoalkyl group, more preferably a group or atom selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, and a halogenoalkyl group, and even more preferably a group or atom selected from the group consisting of a hydrogen atom, an alkyl group, and a halogenoalkyl group. In this case, the alkyl group and the halogenoalkyl group preferably have 1 to 8 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 3 carbon atoms.

[0062] A particularly preferred example of the squarylium compound represented by formula (8) is a compound represented by the following formula (9): １１ ~R １４ , R ２１ ~R ２４ The above explanation is referred to. １ and Ring A ２ is a 6-membered nitrogen-containing heterocycle having only one nitrogen atom as a heteroatom constituting the ring, and the nitrogen-containing heterocycle is R １１ and R ２１ It is preferable that the ring A has no substituents other than １ and Ring A ２ Of the atoms constituting the formula (I), it is preferred that no substituent is bonded to the carbon atom that is not condensed with the benzene ring.

[0063]

[0064] The squarylium compound according to the present disclosure exhibits excellent stability when a squarylium compound solution dissolved in a solvent is stored at low temperature. Therefore, the present disclosure can provide a squarylium compound solution containing a squarylium compound represented by formula (1) and a solvent. An organic solvent is preferably used as the solvent, thereby providing a squarylium compound solution with excellent storage stability. The squarylium compound solution can be applied to, for example, security inks and can be used as an ink composition.

[0065] Examples of the solvent used for the squarylium compound solution include ketones such as methyl ethyl ketone (dipole moment: 2.76 D), methyl isobutyl ketone (dipole moment: 2.56 D), cyclopentanone, and cyclohexanone (dipole moment: 3.01 D); glycol derivatives (e.g., ether compounds, ester compounds, ether ester compounds, etc.) such as PGMEA (2-acetoxy-1-methoxypropane), ethylene glycol mono-n-butyl ether (dipole moment: 2.08 D), ethylene glycol monoethyl ether (dipole moment: 2.08 D), and ethylene glycol ethyl ether acetate; amides such as N,N-dimethylacetamide (dipole moment: 3.72 D); ethyl acetate, propyl acetate, Examples of suitable solvents include esters such as butyl acetate; pyrrolidones such as N-methylpyrrolidone (dipole moment: 4.08 D); aromatic hydrocarbons such as benzene (dipole moment: 0 D), toluene (dipole moment: 0.37 D), and xylene (dipole moment: 0 to 0.44 D); aliphatic hydrocarbons such as cyclohexane and heptane (dipole moment: 0 D); ethers such as tetrahydrofuran (dipole moment: 1.70 D), dioxane, diethyl ether (dipole moment: 1.12 D), and dibutyl ether (dipole moment: 1.22 D); alcohols such as methanol, ethanol, and isopropanol; and halogen-containing aromatic hydrocarbons such as chlorobenzene and o-dichlorobenzene (dipole moment: 2.27 D). These solvents may be used alone or in combination. Oxocarbon compounds have high durability against solvents with small dipole moments. Therefore, a solvent having a dipole moment of 4.0 D or less is preferred, a solvent having a dipole moment of 3.5 D or less is more preferred, and a solvent having a dipole moment of 3.0 D or less is even more preferred. Specific examples of such solvents include o-dichlorobenzene, cyclopentanone, PGMEA, ethylcyclohexane, xylene, toluene, trimethylbenzene, and limonene. Among these, ketones, glycol derivatives, aliphatic hydrocarbons, and aromatic hydrocarbons are preferred.

[0066] The amount of solvent used may be appropriately set depending on the desired concentration of the squarylium compound in the squarylium compound solution, which may be set, for example, in the range of 0.01 to 10% by mass, and may be 0.05% by mass or more, 0.1% by mass or more, or 0.2% by mass or more, or 5% by mass or less, 3% by mass or less, or 1% by mass or less.

[0067] The squarylium compound solution may contain only one type of squarylium compound according to the present disclosure, or two or more types. The squarylium compound solution may contain another dye together with the squarylium compound according to the present disclosure, and may contain, for example, at least one selected from a near-infrared absorbing dye, a visible light absorbing dye, and an ultraviolet absorbing dye. For details of the near-infrared absorbing dye, the visible light absorbing dye, and the ultraviolet absorbing dye, see the explanations of the near-infrared absorbing dye, the visible light absorbing dye, and the ultraviolet absorbing dye that can be contained in the resin composition described below.

[0068] The squarylium compound according to the present disclosure can be mixed with a resin component to form a resin composition. The resin composition contains at least the squarylium compound according to the present disclosure and a resin component. The resin composition according to the present disclosure can be suitably applied to optical filters by being formed into a resin molded article such as a film. Since the squarylium compound according to the present disclosure can function as a near-infrared absorbing dye, an optical filter formed from the resin composition according to the present disclosure can be applied to a near-infrared cut filter. The resin molded article can also be applied to near-infrared absorbing films and plates that block heat rays for energy conservation, solar cell materials that utilize visible light and near-infrared light, specific wavelength absorption filters for plasma display panels (PDPs) and CCDs, etc.

[0069] The resin composition may contain only one squarylium compound according to the present disclosure, or two or more squarylium compounds according to the present disclosure. The resin composition may contain, in addition to the squarylium compound according to the present disclosure, other dyes, for example, at least one selected from a near-infrared absorbing dye, a visible light absorbing dye, and an ultraviolet absorbing dye, as long as the desired performance according to the application is ensured.

[0070] If the resin composition further contains a near-infrared absorbing dye and / or a visible light absorbing dye, an optical filter having light selective transparency can be obtained from the resin composition. For example, when a resin composition contains a squarylium compound according to the present disclosure and a near-infrared absorbing dye, it can be used as a resin composition for an optical filter that suppresses transmission of light over a wide range from red to near-infrared and preferentially transmits light in the visible light region. When a resin composition contains a squarylium compound according to the present disclosure and a visible light absorbing dye, it can be used as a resin composition for a colored filter, a blue light reduction filter, or the like.

[0071] The near-infrared absorbing dye preferably has an absorption maximum in the wavelength range of 600 nm to 1100 nm. More preferably, the near-infrared dye has an absorption peak in the wavelength range of 600 nm to 1100 nm in its absorption spectrum in the wavelength range of 450 nm to 1100 nm, and the absorption maximum of the absorption peak reaches its maximum value in the wavelength range of 450 nm to 1100 nm. The absorption maximum wavelength is more preferably 630 nm or longer, even more preferably 660 nm or longer, and more preferably 1000 nm or shorter, even more preferably 900 nm or shorter, and even more preferably 800 nm or shorter.

[0072] The visible light absorbing dye can be any dye having a maximum absorption wavelength of the maximum absorption peak in the visible light region (for example, a wavelength range of more than 420 nm and less than 680 nm), without any particular limitation. In particular, it is preferable to use a visible light absorbing dye having a maximum absorption wavelength of the maximum absorption peak in the wavelength range of 500 nm or more and less than 680 nm, where visibility is high.

[0073] The near-infrared absorbing dye and the visible light absorbing dye may be organic dyes, inorganic dyes, or organic-inorganic composite dyes (e.g., organic compounds with coordinated metal atoms or ions). Examples of near-infrared absorbing dyes and visible light absorbing dyes include squarylium dyes other than the squarylium compounds according to the present disclosure, croconium dyes, cyclic tetrapyrrole dyes (e.g., porphyrins, chlorins, phthalocyanines, naphthalocyanines, cholines, etc.) that may have copper (e.g., Cu(II)) or zinc (e.g., Zn(II)) as a central metal ion), cyanine dyes, azo dyes, quinone dyes, xanthene dyes, indoline dyes, arylmethane dyes, quaterrylene dyes, diimonium dyes, perylene dyes, quinacrylonitrile dyes, oxazine dyes, dipyrromethene dyes, nickel complex dyes, and copper ion dyes. These dyes may be used alone or in combination of two or more. Among these, it is preferable to use at least one selected from squarylium dyes other than the squarylium compounds according to the present disclosure, croconium dyes, phthalocyanine dyes, cyanine dyes, and dipyrromethene dyes as the near-infrared absorbing dye and visible light absorbing dye, from the viewpoint of being able to effectively absorb light of the desired wavelength. As the near-infrared absorbing dye, it is preferable to use at least one selected from squarylium dyes other than the squarylium compounds according to the present disclosure, croconium dyes, phthalocyanine dyes, and cyanine dyes. This makes it easy to effectively absorb light in the near-infrared region and increase the visible light transmittance. For example, the squarylium compounds and croconium compounds described in JP 2016-074649 A can be used.

[0074] The resin composition may contain an ultraviolet absorbing dye. The ultraviolet absorbing dye preferably has a maximum absorption in the range of 300 nm to 400 nm, for example. By including an ultraviolet absorbing dye in the resin composition, an optical filter having selective light transmission properties in which transmission of light in the ultraviolet to purple region is suppressed can be obtained from the resin composition. Furthermore, deterioration of the resin composition caused by light in the ultraviolet to purple region can be suppressed, and even if the resin composition is exposed to ultraviolet light during storage of the resin composition or during production and processing of the optical filter (for example, vapor deposition or mounting), deterioration of the resin component and other components contained in the resin composition, such as the squarylium compound, from the ultraviolet light can be suppressed.

[0075] As the ultraviolet absorbing dye, known ultraviolet absorbers such as benzotriazole compounds, benzophenone compounds, salicylic acid compounds, benzoxazinone compounds, cyanoacrylate compounds, benzoxazole compounds, merocyanine compounds, and triazine compounds can be used. Only one type of ultraviolet absorbing dye may be used, or two or more types may be used. As the ultraviolet absorbing dye (ultraviolet absorber), commercially available substances may be used, such as the Adekastab (registered trademark) series manufactured by ADEKA Corporation, the TINUVIN (registered trademark) series manufactured by BASF, the DiSlyzer (registered trademark) series manufactured by Sankyo Kasei Co., Ltd., the Sumisorb (registered trademark) series manufactured by Sumitomo Chemical Co., Ltd., the Biosorb (registered trademark) series manufactured by Kyodo Pharmaceutical Co., Ltd., and the Seesorb (registered trademark) series manufactured by Shipro Kasei Co., Ltd. can be used. In addition, the ethylene compounds disclosed in JP 2019-014707 A and JP 2022-158995 A can also be used as the ultraviolet absorbing dye.

[0076] From the viewpoint of achieving the desired performance, the content of the squarylium compound in the resin composition is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, and even more preferably 0.1% by mass or more, based on 100% by mass of the solid content of the resin composition. Furthermore, from the viewpoint of improving the moldability and film-forming properties of the resin composition, the content of the squarylium compound in the resin composition is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on 100% by mass of the solid content of the resin composition. When the resin composition also contains other dyes, it is preferable that the total content of these is within the above range. Note that, when the resin composition contains a solvent, the solid content of the resin composition means the amount of the resin composition excluding the solvent.

[0077] A known resin can be used as the resin component contained in the resin composition. The resin component is preferably one that is highly transparent and can dissolve the squarylium compound according to the present disclosure. When other dyes are used in combination, the resin component is preferably one that can also dissolve the other dyes. By selecting such a resin component, it is possible to achieve both high transmittance in the wavelength range that is desired to be transmitted and high absorbance in the wavelength range that is desired to be blocked.

[0078] The resin component can be not only a polymerized resin, but also a resin raw material (including a resin precursor, raw materials for the precursor, a monomer constituting the resin, etc.) that is incorporated into the resin through a polymerization reaction or a crosslinking reaction when the resin composition is molded, and any resin is included in the resin component. In the latter case, the structure of the squarylium compound may be partially or completely decomposed by unreacted substances, reactive terminal functional groups, ionic groups, catalysts, acidic / basic groups, etc. present in the reaction liquid obtained by the polymerization reaction. Therefore, if such a concern exists, it is desirable to form a resin composition by blending a squarylium compound with a polymerized resin.

[0079] As the resin component, known resins can be used, and it is preferable to use a resin with high transparency. The resin component may be a thermoplastic resin or a thermosetting resin. Examples of the resin component include (meth)acrylic resins, (meth)acrylic urethane resins, polyvinyl chloride resins, polyvinylidene chloride resins, polyolefin resins (e.g., polyethylene resins, polypropylene resins), cycloolefin resins, melamine resins, urethane resins, styrene resins, polyvinyl acetate, polyamide resins (e.g., nylon), aramid resins, polyimide resins, polyamideimide resins, alkyd resins, phenolic resins, epoxy resins, polyester resins (e.g., polybutylene terephthalate (PBT) resins, polyethylene terephthalate (PET) resins, polyarylate resins, etc.), polysulfone resins, butyral resins, polycarbonate resins, poly Examples of suitable resins include ether resins, ABS resins (acrylonitrile butadiene styrene resins), AS resins (acrylonitrile-styrene copolymers), silicone resins, modified silicone resins (e.g., (meth)acrylic silicone resins, alkyl polysiloxane resins, silicone urethane resins, silicone polyester resins, and silicone acrylic resins), and fluorine-based resins (e.g., fluorinated aromatic polymers, polytetrafluoroethylene (PTFE), perfluoroalkoxy fluorine resins (PFA), fluorinated polyaryl ether ketones (FPEK), fluorinated polyimides (FPI), fluorinated polyamic acids (FPAA), and fluorinated polyether nitriles (FPEN)). Among these, (meth)acrylic resins, cycloolefin resins, polyimide resins, polyamide-imide resins, polyester resins, polyarylate resins, polyamide resins, polycarbonate resins, epoxy resins, polysulfone resins, and fluorinated aromatic polymers are preferred from the viewpoints of excellent transparency and heat resistance.

[0080] The (meth)acrylic resin is a polymer having a repeating unit derived from (meth)acrylic acid or its derivative, and for example, a resin having a repeating unit derived from a (meth)acrylic acid ester, such as a poly(meth)acrylic acid ester resin, is preferably used. The (meth)acrylic resin is also preferably one having a ring structure in the main chain, and examples thereof include carbonyl group-containing ring structures such as lactone ring structures, glutaric anhydride structures, glutarimide structures, maleic anhydride structures, and maleimide ring structures; and carbonyl group-free ring structures such as oxetane ring structures, azetidine ring structures, tetrahydrofuran ring structures, pyrrolidine ring structures, tetrahydropyran ring structures, and piperidine ring structures. The carbonyl group-containing ring structures also include structures containing carbonyl group derivative groups such as imide groups. Examples of (meth)acrylic resins having a carbonyl group-containing ring structure that can be used include those described in JP-A Nos. 2004-168882, 2008-179677, WO 2005 / 54311, and 2007-31537.

[0081] The cycloolefin resin is a polymer obtained by polymerizing a cycloolefin as at least a part of a monomer component, and is not particularly limited as long as it has an alicyclic structure in a part of the main chain. Examples of the cycloolefin resin include Topas (registered trademark) manufactured by Polyplastics Co., Ltd., Apel (registered trademark) manufactured by Mitsui Chemicals, Inc., Zeonex (registered trademark) and Zeonor (registered trademark) manufactured by Nippon Zeon Co., Ltd., and Arton (registered trademark) manufactured by JSR Corporation.

[0082] Polyimide resins are polymers containing imide bonds in the repeating units of the main chain, and can be produced, for example, by polymerizing tetracarboxylic dianhydride and diamine to obtain polyamic acid, which is then dehydrated and cyclized (imidized). As the polyimide resin, aromatic polyimides in which aromatic rings are linked by imide bonds are preferably used. Examples of polyimide resins that can be used include Kapton (registered trademark) manufactured by DuPont, Aurum (registered trademark) manufactured by Mitsui Chemicals, Inc., Merdin (registered trademark) manufactured by Saint-Gobain, and TPS (registered trademark) TI3000 series manufactured by Toray Plastics Seiko Co., Ltd.

[0083] The polyamide-imide resin is a polymer containing an amide bond and an imide bond in the repeating unit of the main chain. Examples of the polyamide-imide resin include Torlon (registered trademark) manufactured by Solvay Advanced Polymers, Viromax (registered trademark) manufactured by Toyobo Co., Ltd., and TPS (registered trademark) TI5000 series manufactured by Toray Plastics Seiko Co., Ltd.

[0084] The polyester resin is a polymer containing an ester bond in the repeating unit of the main chain, and can be obtained by, for example, condensation polymerization of a polycarboxylic acid (dicarboxylic acid) and a polyalcohol (diol). Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. Examples of the polyester resin include the OKP series manufactured by Osaka Gas Chemical Co., Ltd., the TRN series manufactured by Teijin Limited, Teonex (registered trademark), Rynite (registered trademark) manufactured by DuPont, Novapex (registered trademark) manufactured by Mitsubishi Chemical Corporation, Novaduran (registered trademark) manufactured by Mitsubishi Engineering Plastics Corporation, and Lumirror (registered trademark) and Toraycon (registered trademark) manufactured by Toray Industries, Inc.

[0085] The polyarylate resin is a polymer obtained by condensation polymerization of a dihydric phenol compound and a dibasic acid (e.g., an aromatic dicarboxylic acid such as phthalic acid), and has a repeating unit containing an aromatic ring and an ester bond in the repeating unit of the main chain. Examples of the polyarylate resin that can be used include Vectran (registered trademark) manufactured by Kuraray Co., Ltd. and U-Polymer (registered trademark) manufactured by Unitika Ltd.

[0086] Polyamide resins are polymers containing amide bonds in the repeating units of their main chains, and can be obtained, for example, by condensation polymerization of diamines and dicarboxylic acids. Polyamide resins may have an aliphatic skeleton in their main chains, and nylon, for example, can be used as such an amide resin. Polyamide resins may have an aromatic skeleton, and aramid resins are known as such polyamide resins. Aramid resins are preferably used because of their excellent heat resistance and high mechanical strength, and examples of such aramid resins include Twaron (registered trademark) and Conex (registered trademark) manufactured by Teijin Limited, and Kevlar (registered trademark) and Nomex (registered trademark) manufactured by DuPont.

[0087] Polycarbonate resin is a polymer containing a carbonate group (—O—(C═O)—O—) in the repeating unit of the main chain. Examples of polycarbonate resins that can be used include Panlite (registered trademark) manufactured by Teijin Limited, Iupizeta (registered trademark) manufactured by Mitsubishi Gas Chemical Company, Inc., Iupilon (registered trademark), Novarex (registered trademark), and Zanter (registered trademark) manufactured by Mitsubishi Engineering Plastics Corporation, and SD Polyca (registered trademark) manufactured by Sumika Styron Polycarbonate Co., Ltd.

[0088] Epoxy resins are resins that can be cured by crosslinking an epoxy compound (prepolymer) in the presence of a curing agent or curing catalyst. Examples of epoxy compounds include aromatic epoxy compounds, aliphatic epoxy compounds, alicyclic epoxy compounds, and hydrogenated epoxy compounds. Examples of such epoxy compounds include fluorene epoxy (Oxol (registered trademark) PG-100) manufactured by Osaka Gas Chemicals Co., Ltd., bisphenol A epoxy compound (JER (registered trademark) 828EL) and hydrogenated bisphenol A epoxy compound (JER (registered trademark) YX8000) manufactured by Mitsubishi Chemical Corporation, and alicyclic liquid epoxy compound (Celloxide (registered trademark) 2021P, EHPE-3150) manufactured by Daicel Corporation.

[0089] Polysulfone resins consist of aromatic rings and sulfonyl groups (-SO ２The polysulfone resin is a polymer having a repeating unit containing a hydroxyl group (-) and an oxygen atom. Examples of polysulfone resins that can be used include Sumikaexcel (registered trademark) PES3600P and PES4100P manufactured by Sumitomo Chemical Co., Ltd., and UDEL (registered trademark) P-1700 manufactured by Solvay Specialty Polymers.

[0090] The fluorinated aromatic polymer is a polymer having a repeating unit containing an aromatic ring having one or more fluorine atoms and at least one bond selected from the group consisting of an ether bond, a ketone bond, a sulfone bond, an amide bond, an imide bond, and an ester bond, and among these, a polymer essentially containing a repeating unit containing an aromatic ring having one or more fluorine atoms and an ether bond is preferred. As the fluorinated aromatic polymer, for example, those described in JP 2008-181121 A can be used.

[0091] The resin preferably has high transparency, which makes it easier to suitably apply the resin composition to optical applications. For example, the resin preferably has a total light transmittance of 75% or more at a thickness of 0.1 mm, more preferably 80% or more, and even more preferably 85% or more. The upper limit of the total light transmittance of the resin is not particularly limited, and the total light transmittance may be 100% or less, but may be, for example, 95% or less. The total light transmittance is measured based on JIS K 7105.

[0092] The glass transition temperature (Tg) of the resin is not particularly limited, but is preferably relatively high, which can improve the heat resistance of the resin layer formed from the resin composition. The glass transition temperature of the resin is, for example, preferably 110°C or higher, more preferably 120°C or higher, and even more preferably 130°C or higher. The upper limit of the glass transition temperature of the resin is not particularly limited, but is preferably, for example, 380°C or lower, from the viewpoint of improving the moldability of the resin composition.

[0093] The resin component preferably has high transparency, which makes it easier to suitably apply the resin composition to optical applications. For example, the resin component preferably has a total light transmittance of 75% or more at a thickness of 0.1 mm, more preferably 80% or more, and even more preferably 85% or more. The upper limit of the total light transmittance of the resin component is not particularly limited, and the total light transmittance may be 100% or less, but may be, for example, 95% or less. The total light transmittance is measured based on JIS K 7105.

[0094] The resin composition may contain a solvent. For example, when the resin composition is a paint-formed resin composition, the inclusion of a solvent makes it easier to apply the resin composition. A resin composition containing a solvent can also be used as an ink composition.

[0095] The solvent may function to dissolve each component contained in the resin composition or may function as a dispersion medium, but is preferably one that dissolves the squarylium compound according to the present disclosure. As the solvent, any of the solvents usable for the squarylium compound solution described above can be used.

[0096] The content of the solvent is, for example, preferably 50% by mass or more, more preferably 70% by mass or more, and preferably less than 100% by mass, more preferably 95% by mass or less, based on 100% by mass of the resin composition. By adjusting the content of the solvent within this range, it becomes easier to obtain a resin composition having a high concentration of the squarylium compound.

[0097] The resin composition may contain a surface conditioner, which can prevent appearance defects such as striations and dents from occurring in the resin layer when the resin composition is cured to form a resin layer. The type of surface conditioner is not particularly limited, and siloxane-based surfactants, acetylene glycol-based surfactants, fluorine-based surfactants, acrylic leveling agents, etc. can be used. Examples of surface conditioners that can be used include the BYK (registered trademark) series manufactured by BYK-Chemie and the KF series manufactured by Shin-Etsu Chemical Co., Ltd.

[0098] The resin composition may contain a dispersant, which stabilizes the dispersibility of the squarylium compound even when a portion of the squarylium compound is present in a dispersed state in the resin composition, thereby suppressing re-aggregation of the squarylium compound. The type of dispersant is not particularly limited, and examples that can be used include the EFKA series manufactured by EFKA Additives, the BYK (registered trademark) series manufactured by BYK-Chemie, the Solsperse (registered trademark) series manufactured by The Lubrizol Corporation of Japan, the Disparlon (registered trademark) series manufactured by Kusumoto Chemicals, Ltd., the Ajisper (registered trademark) series manufactured by Ajinomoto Fine-Techno Co., Ltd., the KP series manufactured by Shin-Etsu Chemical Co., Ltd., the Polyflow series manufactured by Kyoeisha Chemical Co., Ltd., the Megafac (registered trademark) series manufactured by DIC Corporation, and the Disper Aid series manufactured by San Nopco.

[0099] The resin composition may contain a silane coupling agent or its hydrolysate or hydrolyzed condensate, which can enhance the adhesion of the resin layer to the substrate when the resin composition is cured on a substrate to form a resin layer.

[0100] The resin composition may contain various additives such as a plasticizer, a surfactant, a viscosity modifier, an antifoaming agent, an antiseptic, and a resistivity modifier, as required.

[0101] A molded article can be obtained by forming the resin composition into a predetermined shape. The molded article may be formed by curing the resin composition by heating (softening) and cooling it, by curing it through a reaction of the resin components (e.g., a polymerization reaction or a crosslinking reaction), or by curing it by removing the solvent contained in the resin composition. Examples of the resin composition that can be used include thermoplastic resin compositions that can be molded by injection molding, extrusion molding, etc., and resin compositions that have been made into paints so that they can be applied by spin coating, solvent casting, roll coating, spray coating, bar coating, dip coating, screen printing, flexographic printing, inkjet printing, etc.

[0102] When the resin composition is a thermoplastic resin composition, a molded article can be obtained by subjecting the resin composition to injection molding, extrusion molding, vacuum molding, compression molding, blow molding, or the like. In this method, a molded article can be obtained by blending a squarylium compound with a thermoplastic resin and heat-molding the mixture. For example, the squarylium compound can be added to a powder or pellet of a base resin, heated to about 150°C to 350°C, dissolved, and then molded. The shape of the molded article is not particularly limited, and examples include plate-like, sheet-like, granular, powder-like, block-like, particle aggregate-like, spherical, oval-spherical, lenticular, cubic, columnar, rod-like, conical, cylindrical, needle-like, fibrous, hollow fiber-like, and porous shapes. Furthermore, when kneading the resin, additives typically used in resin molding, such as plasticizers, may be added.

[0103] When the resin composition is a paint-formed resin composition, a liquid or paste-like resin composition containing a squarylium compound can be applied to a substrate (e.g., a resin plate, a film, a glass plate, etc.) to obtain a film-like molded article having a thickness of 200 μm or less or a sheet-like molded article having a thickness of more than 200 μm. The molded article thus obtained can be peeled from the substrate and handled as a film or sheet, or can be handled integrally with the substrate.

[0104] The molded article of the resin composition may be composed of a single resin layer (a layer formed by curing the resin composition) or may be composed of multiple resin layers. When the molded article is handled as an integral part of a substrate, the molded article may be formed on only one side of the substrate, or on both sides. Note that the molded article and the substrate may also be integrated by thermocompression bonding or chemical bonding a molded article formed from the resin composition to the substrate.

[0105] The resin composition according to the present disclosure can be preferably used as a resin composition for forming filters used in various applications such as optical devices, display devices, mechanical parts, and electrical / electronic parts. The resin composition and its molded article can be suitably applied to optical filters such as near-infrared cut filters, and the optical filter thus formed has a resin layer formed from the resin composition according to the present disclosure. The optical filter may be formed from a single or multiple resin layers, or may be formed integrally with a support.

[0106] A filter integrated with a support can be formed, for example, by applying the resin composition to the surface of the support (or, if another layer such as a binder layer is present between the support and the resin layer, to the surface of the other layer) by spin coating or solvent casting, followed by drying or curing. Alternatively, a filter can be formed by thermocompression bonding a sheet-shaped molded article formed from the resin composition to the support.

[0107] The resin layer formed from the resin composition may be provided on only one side of the support, or on both sides. The thickness of the resin layer is not particularly limited, but from the viewpoint of ensuring the desired near-infrared cut performance, it is, for example, preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 2 μm or more, and preferably 1 mm or less, more preferably 500 μm or less, and even more preferably 200 μm or less. When the resin layer is formed by coating a paint-formed resin composition on the support, the strength of the filter can be ensured by the support, so the thickness of the resin layer can be further reduced. When the resin layer is formed on the support, the thickness of the resin layer is, for example, preferably 50 μm or less, more preferably 20 μm or less, even more preferably 10 μm or less, and particularly preferably 5 μm or less.

[0108] As the support, it is preferable to use a transparent substrate such as a resin plate, resin film, or glass plate. The resin plate or resin film used as the support is preferably formed from, for example, the resin components described above. From the viewpoint of improving the heat resistance of the optical filter, it is preferable to use a glass substrate as the support, and the optical filter thus formed can be mounted on an electronic component, for example, by solder reflow. Furthermore, since glass substrates are less likely to crack or warp even when exposed to high temperatures, adhesion with the resin layer is more easily ensured. When a glass substrate is used as the support, a binder layer formed from, for example, a silane coupling agent may be provided between the support and the resin layer, thereby improving the adhesion between the resin layer and the glass substrate. Incidentally, the adhesion between the resin layer and the glass substrate can also be improved by adding a silane coupling agent as an adhesion improver to the resin composition forming the resin layer.

[0109] The thickness of the support (substrate) is, for example, preferably 0.05 mm or more, more preferably 0.1 mm or more, from the viewpoint of ensuring strength, and is preferably 0.4 mm or less, more preferably 0.3 mm or less, from the viewpoint of thinning.

[0110] A protective layer made of the same or a different resin as that of the resin layer may be laminated as a second resin layer on the resin layer formed from the resin composition. By providing the protective layer, the durability (decomposition resistance) of the squarylium compound contained in the resin layer can be increased. The protective layer may be provided on only one side of the resin layer or on both sides. When the resin layer is provided on a support, the protective layer is preferably provided on the side of the resin layer opposite the support.

[0111] When an optical filter is formed from the resin composition, the optical filter may have a layer (anti-reflection film) having anti-reflection or anti-glare properties that reduce reflections from fluorescent lights, etc., a layer having scratch resistance, a transparent substrate having other functions, etc. The optical filter may have a near-infrared reflective film or an ultraviolet reflective film. These anti-reflection films, reflective films, or other layers are preferably provided on the light incident side of the resin layer.

[0112] Near-infrared reflective films, ultraviolet reflective films, and anti-reflection films (visible light anti-reflection films) can be composed of dielectric films. The dielectric film is typically composed of a dielectric multilayer film in which high-refractive index material layers and low-refractive index material layers are alternately stacked, but it may also be composed of only one of the high-refractive index material layers and the low-refractive index material layers. The high-refractive index material layer can be composed of a material with a refractive index of 1.7 or higher. A material with a refractive index ranging from 1.7 to 2.5 is preferably selected, with a refractive index ranging from 1.8 or higher being more preferred, and a refractive index of 2.0 or higher being even more preferred. Examples of materials that can be used to compose the high-refractive index material layer include oxides such as titanium oxide, zinc oxide, zirconium oxide, lanthanum oxide, yttrium oxide, indium oxide, niobium oxide, tantalum oxide, tin oxide, and bismuth oxide; nitrides such as silicon nitride; mixtures of these oxides and nitrides, and mixtures thereof doped with metals such as aluminum and copper or carbon (e.g., tin-doped indium oxide (ITO) and antimony-doped tin oxide (ATO)). The material constituting the low refractive index material layer can be a material with a refractive index of less than 1.7, and preferably a material with a refractive index in the range of 1.2 to 1.6, and more preferably a material with a refractive index in the range of 1.3 to 1.5. Examples of materials constituting the low refractive index material layer include silicon oxide (silica, SiOx (x = 1 to 2)), alumina, lanthanum fluoride, magnesium fluoride, and sodium aluminum hexafluoride. Among these, the high refractive index material layer is preferably composed of titanium oxide, and the low refractive index material layer is preferably composed of silicon oxide.

[0113] The thickness of each of the high refractive index material layer and the low refractive index material layer is preferably adjusted to a range of 0.1λ to 0.5λ, more preferably 0.2λ to 0.3λ, of the wavelength λ (nm) of light to be blocked. By forming the dielectric film in this manner, it is possible to selectively reflect light in a desired wavelength range, and the dielectric film can be used to form a near-infrared reflective film, an ultraviolet reflective film, an anti-reflective film (visible light anti-reflective film), etc. The ultraviolet reflective film and the near-infrared reflective film may be a single film that has both ultraviolet and near-infrared reflective functions.

[0114] The number of layers in the dielectric film is not particularly limited as long as it is one or more, but from the viewpoint of exhibiting the desired optical performance as a near-infrared reflective film, an ultraviolet reflective film, an anti-reflection film, etc., it is preferably, for example, 2 to 80 layers. The number of layers in the dielectric film may be 5 or more, 10 or more, or 20 or more, and may be 70 or less, or 60 or less. The thickness of the dielectric film is not particularly limited and may be, for example, in the range of 0.01 μm to 10 μm, but from the viewpoint of sufficiently blocking the incidence of light in the desired wavelength range, it is preferably 0.02 μm or more, more preferably 0.03 μm or more, and from the viewpoint of thinning, it is preferably 5 μm or less, more preferably 3 μm or less.

[0115] The optical filter may have an aluminum vapor deposition film, a noble metal thin film, a resin film in which metal oxide fine particles containing indium oxide as the main component and a small amount of tin oxide are dispersed, or the like.

[0116] The thickness of the optical filter is preferably, for example, 1 mm or less. This makes it possible to fully meet the demand for miniaturization of image sensors, for example. The thickness of the optical filter is more preferably 500 μm or less, even more preferably 300 μm or less, and even more preferably 150 μm or less, and is preferably 30 μm or more, and even more preferably 50 μm or more.

[0117] Optical filters can be used as one of the components of sensors such as image sensors (imaging elements), illuminance sensors, and proximity sensors. For example, image sensors are used as electronic components that convert light from a subject into an electrical signal or the like and output the signal, and examples of such sensors include CCDs (Charge Coupled Devices) and CMOSs ​​(Complementary Metal-Oxide Semiconductors). Image sensors can be used in mobile phone cameras, digital cameras, in-vehicle cameras, surveillance cameras, display elements (LEDs, etc.), and the like. The sensor includes one or more of the optical filters described above and may further include other filters (for example, a visible light cut filter, an infrared cut filter, an ultraviolet cut filter, etc.) and lenses, as necessary.

[0118] This application claims the benefit of priority based on Japanese Patent Application No. 2024-125042, filed on July 31, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-125042, filed on July 31, 2024, are incorporated herein by reference.

[0119] The contents of the present disclosure will be explained in more detail below using examples, but the contents of the present disclosure are not limited to the following examples, and can be implemented with appropriate modifications within the scope that is consistent with the intent described above and below, and all of these modifications are included in the technical scope of the present disclosure.

[0120] (1) Synthesis of Compounds (1-1) Synthesis Example 1: Synthesis of Squarylium Compound 1 Intermediate 1A was synthesized according to the method described in Example 1-3 of JP 2016-74649 A. Next, 0.50 g (2.45 mmol) of intermediate 1A, 1.12 g (4.91 mmol) of DL-benzilic acid, and 15 g of toluene were placed in a 100 mL four-neck flask, and the mixture was allowed to react for 6 hours under reflux conditions while stirring using a magnetic stirrer under a nitrogen flow (20 mL / min). After completion of the reaction, the organic phase obtained by filtering the reaction solution was concentrated using an evaporator, and the concentrated solution was purified by column chromatography using silica gel (developing solvent: ethyl acetate), yielding 1.20 g of intermediate 1B. The yield relative to intermediate 1A was 59 mol%.

[0121] Next, 1.20 g (2.89 mmol) of Intermediate 1B and 6.6 g of ultra-dehydrated tetrahydrofuran were placed in a 100 mL four-neck flask. Under nitrogen flow (5 mL / min), 0.44 g (0.0433 mmol) of triethylamine and 0.92 g (3.18 mmol) of palmitoyl chloride were added while stirring using a magnetic stirrer. The reaction was allowed to proceed at room temperature for 12 hours. After completion of the reaction, the resulting reaction solution was added to ion-exchanged water and extracted with chloroform. Anhydrous magnesium sulfate was added to the extracted organic phase for dehydration. After filtering the solids (inorganic components) from the organic phase, the solvent was concentrated using an evaporator. The mixture was then subjected to silica gel column chromatography (developing solvent: chloroform), followed by concentration and vacuum drying, yielding 1.08 g of Intermediate 1C. The yield relative to Intermediate 1B was 57.1 mol%.

[0122] Next, 1.08 g (1.65 mmol) of intermediate 1C, 0.094 g (0.83 mmol), 5.4 g of 1-butanol, and 5.4 g of toluene were placed in a 100 mL four-neck flask, and the mixture was stirred using a magnetic stirrer under a nitrogen flow (10 mL / min). The mixture was then reacted under reflux conditions for 3 hours while removing the eluted water using a Dean-Stark apparatus. After the reaction was completed, the mixture was cooled to room temperature, and the precipitate was separated by filtration. The separated precipitate was washed with methanol, and the precipitate was filtered again. The resulting cake (solid) was appropriately purified by column chromatography using silica or alumina (developing solvent: chloroform). The resulting purified product was dried at 60°C for 12 hours using a vacuum dryer, yielding 0.10 g of the target squarylium compound 1. The yield relative to squaric acid was 4.4 mol%.

[0123]

[0124] (1-2) Synthesis Example 2: Synthesis of squarylium compound 2 The squarylium compound 2 shown in Table 1 was obtained in the same manner as in Synthesis Example 1, except that 9-hydroxyfluorene-9-carboxylic acid was used instead of DL-benzilic acid. The yield based on squaric acid was 7.1 mol %.

[0125] (1-3) Synthesis Example 3: Synthesis of squarylium compound 3 The squarylium compound 3 shown in Table 1 was obtained in the same manner as in Synthesis Example 1, except that L-phenyllactonic acid was used instead of DL-benzilic acid. The yield based on squaric acid was 6.5 mol %.

[0126] (1-4) Synthesis Example 4: Synthesis of squarylium compound 4 The squarylium compound 4 shown in Table 1 was obtained in the same manner as in Synthesis Example 1, except that 2-hydroxypalmitic acid was used instead of DL-benzilic acid and 2,2-dimethylbutyryl chloride was used instead of palmitoyl chloride. The yield based on squaric acid was 49.0 mol%.

[0127] (1-5) Synthesis Example 5: Synthesis of squarylium compound 5 Squarylium compound 5 shown in Table 1 was obtained in the same manner as in Synthesis Example 1, except that 2-hydroxypalmitic acid was used instead of DL-benzilic acid. The yield based on squaric acid was 63.1 mol %.

[0128] (1-6) Synthesis Example 6: Synthesis of squarylium compound 6 3.00 g (5.89 mmol) of 2-hexadecyl octadecanoic acid and 28.1 g (0.236 mol) of thionyl chloride were placed in a 100 mL four-neck flask and stirred for 1 hour at 40°C under a nitrogen flow (20 mL / min) using a magnetic stirrer. Thereafter, excess thionyl chloride was distilled off under reduced pressure to obtain 3.11 g of 2-hexadecyl octadecanoyl chloride (acid chloride 1). The yield based on 2-hexadecyl octadecanoic acid was 100 mol%.

[0129] Next, 0.20 g (0.95 mmol) of Intermediate 1A and 2.5 g of ultra-dehydrated tetrahydrofuran were placed in a 50 mL three-neck flask. Under nitrogen flow (5 mL / min), 0.14 g (1.43 mmol) of triethylamine and 0.55 g (1.05 mmol) of acid chloride 1 were added while stirring using a magnetic stirrer. The mixture was allowed to react at room temperature for 12 hours. After completion of the reaction, the resulting reaction solution was added to ion-exchanged water and extracted with chloroform. Anhydrous magnesium sulfate was added to the extracted organic phase for dehydration. After filtering the solids (inorganic components) from the organic phase, the solvent was concentrated using an evaporator. The mixture was then subjected to silica gel column chromatography (developing solvent: chloroform), followed by concentration and vacuum drying, to obtain 0.58 g of Intermediate 6A. The yield relative to Intermediate 1A was 87.5 mol%.

[0130] Next, 0.58 g (0.834 mmol) of intermediate 6A, 0.05 g (0.417 mmol) of squaric acid, 2.9 g of 1-butanol, and 2.9 g of toluene were placed in a 50 mL two-neck flask, and the mixture was stirred using a magnetic stirrer under a nitrogen flow (10 mL / min). The reaction was carried out under reflux conditions for 3 hours while removing the eluted water using a Dean-Stark apparatus. After the reaction was completed, the mixture was cooled to room temperature, and the precipitate was separated by filtration. The separated precipitate was washed with methanol, and the precipitate was filtered again. The resulting cake (solid) was appropriately purified by column chromatography using silica or alumina (developing solvent: chloroform). The resulting purified product was dried at 60°C for 12 hours using a vacuum dryer, yielding 0.32 g of the target squarylium compound 6. The yield relative to squaric acid was 52.8 mol%.

[0131]

[0132] (1-7) Synthesis Example 7: Synthesis of squarylium compound 7 A 100 mL four-neck flask was charged with 7.4 g of acetonitrile, 0.34 g of acetic acid, 1.00 g (5.61 mmol) of 7-nitro-1,2,3,4-tetrahydroquinoline, and 2.62 g (12.4 mmol) of sodium triacetoxyborohydride, and 3.93 g (12.4 mmol) of 3,5-dibenzyloxybenzaldehyde was added dropwise over 10 minutes under nitrogen flow (10 mL / min) while stirring with a stirring blade. After completion of the dropwise addition, 11 g of toluene was added to the resulting reaction solution, and the mixture was neutralized with an aqueous sodium hydroxide solution. After the aqueous phase was removed, an aqueous sodium chloride solution was added, and the mixture was stirred and allowed to stand, and the organic phase was removed. This operation was repeated three times, and then anhydrous sodium sulfate was added to the resulting organic phase for dehydration. After filtering out solid matter from this organic phase, the solvent was concentrated using an evaporator, and then the residue was subjected to silica gel column chromatography (developing solvent: chloroform) as appropriate, followed by concentration and vacuum drying to obtain Intermediate 7A.

[0133] Next, the entire amount of Intermediate 7A and 16.2 g of concentrated hydrochloric acid (hydrochloric acid concentration 36 wt%) were placed in a 100 mL two-neck flask. Under nitrogen flow (5 mL / min), 4.3 g of tin chloride dihydrate was added little by little while stirring using a magnetic stirrer, while taking care not to generate heat of reaction. After the addition, the mixture was stirred at room temperature for about 3 hours. 8.2 g of toluene was then added, and the mixture was stirred and allowed to stand, after which the organic phase was extracted. This operation was repeated three times, after which 7.5 g of sodium hydroxide and 32.4 g of ethyl acetate were added, taking care not to generate heat, to neutralize the aqueous phase. The organic phase was then extracted, and 16.2 g of ethyl acetate was added, followed by stirring and allowing to stand, after which the aqueous phase was extracted. This operation was repeated three times, after which anhydrous magnesium sulfate was added to the organic phase to dehydrate it. After filtering off the solid matter from the organic phase, the solvent was concentrated using an evaporator, and then the residue was concentrated and vacuum dried using silica gel column chromatography (developing solvent: chloroform) to obtain 1.52 g of Intermediate 7B. The yield relative to Intermediate 7A was 60.0 mol %.

[0134] Next, squarylium compound 7 was obtained in the same manner as in Synthesis Example 6, except that intermediate 7B was used instead of intermediate 1A. The yield based on squaric acid was 62.1 mol %.

[0135]

[0136] (1-8) Synthesis Example 8: Synthesis of squarylium compound 8 The squarylium compound 8 shown in Table 1 was obtained in the same manner as in Synthesis Example 1, except that 2-hydroxypalmitic acid was used instead of DL-benzilic acid and pentafluorobenzenesulfonyl chloride was used instead of palmitoyl chloride. The yield based on squaric acid was 32.1 mol %.

[0137] (1-9) Synthesis Example 9: Synthesis of squarylium compound 9 2.00 g (9.79 mmol) of intermediate 1A, 2.98 g (19.6 mmol) of DL-mandelic acid, and 60 g of toluene were placed in a 200 mL four-neck flask, and the mixture was allowed to react for 6 hours under reflux conditions while stirring using a magnetic stirrer under a nitrogen flow (20 mL / min). After completion of the reaction, the reaction solution was filtered, and the resulting organic phase was concentrated using an evaporator. The concentrate was purified by silica gel column chromatography (developing solvent: ethyl acetate), yielding 2.09 g of intermediate 9A. The yield relative to intermediate 1A was 63.0 mol%.

[0138] Next, 0.86 g (2.54 mmol) of Intermediate 9A, 0.86 g (12.7 mmol) of imidazole, and 8.6 g of N,N-dimethylformamide were added to a 100 mL four-neck flask, and while stirring using a magnetic stirrer under a nitrogen flow (10 mL / min), 3.49 g (12.7 mmol) of tert-butyldiphenylchlorosilane was added while taking care to avoid heat generation, and the reaction was carried out at room temperature for 12 hours. After completion of the reaction, the reaction solution was concentrated using an evaporator, and the concentrated solution was purified by column chromatography using silica gel (developing solvent: ethyl acetate), yielding 1.50 g of Intermediate 9B. The yield based on Intermediate 9A was 100 mol%.

[0139] Next, 1.50 g (0.260 mmol) of intermediate 9B, 0.12 g (1.04 mmol), 7.5 g of 1-butanol, and 7.5 g of toluene were placed in a 50 mL two-neck flask, and the mixture was stirred using a magnetic stirrer under a nitrogen flow (10 mL / min). The mixture was then reacted under reflux conditions for 3 hours while removing the eluted water using a Dean-Stark apparatus. After the reaction was completed, the mixture was cooled to room temperature, and the precipitate was separated by filtration. The separated precipitate was washed with methanol, and the precipitate was filtered again. The resulting cake (solid) was appropriately purified by column chromatography using silica or alumina (developing solvent: chloroform). The resulting purified product was dried at 60°C for 12 hours using a vacuum dryer, yielding 0.24 g of the target squarylium compound 9. The yield relative to squaric acid was 22.4 mol%.

[0140]

[0141] (1-10) Synthesis Example 10: Synthesis of squarylium compound 10 7.4 g of acetonitrile, 0.34 g of acetic acid, 1.00 g (5.61 mmol) of 7-nitro-1,2,3,4-tetrahydroquinoline, and 2.62 g (12.3 mmol) of sodium triacetoxyborohydride were placed in a 100 mL four-neck flask, and 2.99 g (12.3 mmol) of 3,5-bis(trifluoromethyl)benzaldehyde was added dropwise over 10 minutes under nitrogen flow (10 mL / min) while stirring with a stirring blade. After completion of the dropwise addition, 11 g of toluene was added to the resulting reaction solution, and the mixture was neutralized with an aqueous sodium hydroxide solution. After the aqueous phase was removed, an aqueous sodium chloride solution was added, and the mixture was stirred and allowed to stand, and the organic phase was removed. This operation was repeated three times, and then anhydrous sodium sulfate was added to the resulting organic phase for dehydration. After filtering out solid matter (inorganic matter) from this organic phase, the solvent was concentrated using an evaporator, and then the residue was subjected to silica gel column chromatography (developing solvent: chloroform) as appropriate, followed by concentration and vacuum drying, thereby obtaining Intermediate 10A.

[0142] Next, the entire amount of Intermediate 10A and 16.2 g of concentrated hydrochloric acid (hydrochloric acid concentration 36 wt%) were placed in a 100 mL two-neck flask. Under nitrogen flow (5 mL / min), 4.3 g of tin chloride dihydrate was added little by little while stirring using a magnetic stirrer, while taking care not to generate heat of reaction. After the addition, the mixture was stirred at room temperature for about 3 hours. 8.2 g of toluene was then added, and the mixture was stirred and allowed to stand, after which the organic phase was extracted. This operation was repeated three times, after which 7.5 g of sodium hydroxide and 32.4 g of ethyl acetate were added, taking care not to generate heat, to neutralize the aqueous phase. The organic phase was then extracted, and 16.2 g of ethyl acetate was added, followed by stirring and allowing to stand, after which the aqueous phase was extracted. This operation was repeated three times, after which anhydrous magnesium sulfate was added to the organic phase to dehydrate it. After filtering the solid matter from the organic phase, the solvent was concentrated using an evaporator, and then the residue was concentrated and vacuum-dried using silica gel column chromatography (developing solvent: chloroform) to obtain 0.67 g of Intermediate 10B. The yield relative to Intermediate 10A was 45.0 mol %.

[0143] Next, 0.50 g (1.34 mmol) of Intermediate 10B, 0.41 g (2.67 mmol) of DL-mandelic acid, and 7.0 g of toluene were placed in a 100 mL four-neck flask, and the mixture was allowed to react for 6 hours under reflux conditions while stirring using a magnetic stirrer under a nitrogen flow (20 mL / min). After completion of the reaction, the reaction solution was filtered and the resulting organic phase was concentrated using an evaporator. The concentrated solution was purified by column chromatography using silica gel (developing solvent: ethyl acetate), yielding 0.34 g of Intermediate 10C. The yield relative to Intermediate 10B was 50.1 mol%.

[0144] Next, 0.34 g (0.67 mmol) of intermediate 10C, 0.09 g (1.34 mmol) of imidazole, and 1.0 g of N,N-dimethylformamide were added to a 50 mL three-neck flask, and while stirring using a magnetic stirrer under a nitrogen flow (10 mL / min), 0.37 g (1.34 mmol) of tert-butyldiphenylchlorosilane was added while taking care to avoid heat generation, and the reaction was carried out at room temperature for 12 hours. After completion of the reaction, the reaction solution was concentrated using an evaporator, and the concentrated solution was purified by column chromatography using silica gel (developing solvent: ethyl acetate), yielding 0.43 g of intermediate 10D. The yield based on intermediate 10C was 87.0 mol%.

[0145] Next, 0.43 g (0.58 mmol) of intermediate 10C, 0.12 g (0.29 mmol) of squaric acid, 3.0 g of 1-butanol, and 3.0 g of toluene were placed in a 50 mL two-neck flask, and the mixture was stirred using a magnetic stirrer under a nitrogen flow (10 mL / min), and the reaction was carried out under reflux conditions for 3 hours while removing the eluted water using a Dean-Stark apparatus. After the reaction was completed, the mixture was cooled to room temperature, and the precipitate was separated by filtration. The separated precipitate was washed with methanol, and the precipitate was filtered again. The resulting cake (solid) was appropriately purified by column chromatography using silica or alumina (developing solvent: chloroform). The resulting purified product was dried at 60°C for 12 hours using a vacuum dryer, yielding 0.14 g of the target squarylium compound 10. The yield relative to squaric acid was 31.0 mol%.

[0146]

[0147] (1-11) Synthesis Example 11: Synthesis of squarylium compound 11 The squarylium compound 11 shown in Table 2 was obtained in the same manner as in Synthesis Example 1, except that DL-benzilic acid was changed to DL-mandelic acid. The yield based on squaric acid was 50.6 mol%.

[0148] (1-12) Synthesis Example 12: Synthesis of squarylium compound 12 The squarylium compound 12 shown in Table 2 was obtained in the same manner as in Synthesis Example 1, except that DL-benzilic acid was changed to 4-fluoro-DL-mandelic acid. The yield based on squaric acid was 61.2 mol%.

[0149] (1-13) Synthesis Example 13: Synthesis of squarylium compound 13 The squarylium compound 13 shown in Table 2 was obtained in the same manner as in Synthesis Example 1, except that DL-benzilic acid was changed to 4-trifluoromethyl-DL-mandelic acid. The yield based on squaric acid was 60.5 mol%.

[0150] (1-14) Synthesis Example 14: Synthesis of squarylium compound 14 The squarylium compound 14 shown in Table 2 was obtained in the same manner as in Synthesis Example 1, except that DL-benzilic acid was changed to 2-fluoro-DL-mandelic acid. The yield based on squaric acid was 41.1 mol%.

[0151] (1-15) Synthesis Example 15: Synthesis of squarylium compound 15 The squarylium compound 15 shown in Table 2 was obtained in the same manner as in Synthesis Example 1, except that DL-tropic acid was used instead of DL-benzilic acid. The yield based on squaric acid was 8.9 mol %.

[0152] (1-16) Synthesis Example 16: Synthesis of squarylium compound 16 The squarylium compound 16 shown in Table 2 was obtained in the same manner as in Synthesis Example 6, except that Intermediate 10B was used instead of Intermediate 1A in Synthesis Example 6. The yield based on squaric acid was 50.1 mol%.

[0153] (1-17) Synthesis Example 17: Synthesis of squarylium compound 17 Intermediate 17B was obtained instead of intermediate 10B by the same procedure as in Synthesis Example 10, except that 3-trifluoromethylbenzaldehyde was used instead of 3,5-bis(trifluoromethyl)benzaldehyde in Synthesis Example 10. Next, squarylium compound 17 shown in Table 3 was obtained by the same procedure as in Synthesis Example 6, except that intermediate 17B was used instead of intermediate 1A in Synthesis Example 6. The yield based on squaric acid was 23.0 mol%.

[0154] (1-18) Synthesis Example 18: Synthesis of squarylium compound 18 110 g of chloroform, 1.8 g of acetic acid, 5.0 g (0.0303 mol) of 6-nitroindoline, and 12.84 g (0.0606 mol) of sodium triacetoxyborohydride were placed in a 300 mL four-neck flask, and 4.37 g (0.0606 mol) of isobutyraldehyde was added dropwise over 10 minutes while stirring with a stirring blade under a nitrogen flow (10 mL / min). After completion of the dropwise addition, the resulting reaction solution was added to 300 g of water and neutralized with hydrochloric acid. 300 g of ethyl acetate was added thereto, and the organic phase was extracted using a separatory funnel. Anhydrous magnesium sulfate was added to the extracted organic phase for dehydration. After filtering off solids (inorganic components) from the organic phase, the solvent was concentrated using an evaporator, and then the concentrate was subjected to silica gel column chromatography (developing solvent: chloroform) as appropriate, followed by concentration and vacuum drying to obtain 3.36 g of Intermediate 18A. The yield based on 6-nitroindoline was 50.4%.

[0155] Next, intermediate 18B was obtained in place of intermediate 10B by the same procedure as in Synthesis Example 10, except that intermediate 18A was used instead of intermediate 10A in Synthesis Example 10. Next, squarylium compound 18 shown in Table 3 was obtained by the same procedure as in Synthesis Example 6, except that intermediate 18B was used instead of intermediate 1A in Synthesis Example 6. The yield based on squaric acid was 34.1 mol%.

[0156] (1-19) Synthesis Example 19: Synthesis of comparative squarylium compound 1 Comparative squarylium compound 1 shown in Table 3 was synthesized according to Synthesis Example 4 of Patent Document 5 (JP 2019-031637 A).

[0157]

[0158]

[0159]

[0160] (2) Squarylium Compound Solution (2-1) Evaluation of Coagulation Properties Toluene solutions of squarylium compounds 1 to 18 and comparative squarylium compound 1 were prepared. The toluene solutions of the squarylium compounds were prepared by mixing the squarylium compound and toluene at 25°C in a mass ratio of 0.28:99.72, subjecting the mixture to ultrasonic treatment for 15 minutes, and filtering the mixture through a filter with a pore size of 0.45 μm (GL Sciences, GL Chromatodisc, non-aqueous 13N). The toluene solutions of the squarylium compounds were allowed to stand overnight in a freezer at -20°C, then slowly removed from the freezer, and visually inspected for the presence or absence of coagulation. The results are shown in Table 4.

[0161] (2-2) Spectroscopic Measurement Chloroform or toluene solutions of squarylium compounds 1 to 18 and comparative squarylium compound 1 were prepared, and their absorption spectra were measured in the wavelength range of 300 nm to 1100 nm. The concentration of each squarylium compound solution was adjusted so that the transmittance at the absorption maximum wavelength was 10% (±0.05%). The light transmittance was measured at a measurement interval of 1 nm using a spectrophotometer (Shimadzu Corporation, UV-1800), and the wavelength at which absorption was maximum in the wavelength range of 300 nm to 1100 nm (maximum absorption wavelength λmax) was determined. The results are shown in Table 4.

[0162]

[0163] (2-3) Results All of squarylium compounds 1 to 18 exhibited absorption maximum wavelengths close to that of comparative squarylium compound 1. When a toluene solution of comparative squarylium compound 1 was left standing overnight at −20°C, the toluene solution solidified, as shown in FIG. 3, making it difficult to handle as a solution. On the other hand, when a toluene solution of squarylium compounds 1 to 18 was left standing overnight at −20°C, the solution did not solidify, as shown in FIG. 4. Squarylium compounds 1 to 18 can suppress solidification when stored in solution at low temperatures while maintaining the optical properties of existing useful squarylium compounds.

[0164] (3) Resin Composition (3-1) Preparation of Resin Composition 1: A 2-liter reaction vessel equipped with a stirring blade was charged with 10.01 g (0.044 mol) of 2,2'-bis(4-hydroxyphenyl)propane, 3.59 g (0.090 mol) of sodium hydroxide, and 300 g of ion-exchanged water. After dissolving, 0.89 g (0.009 mol) of triethylamine was added and dissolved. A solution of 3.57 g (0.021 mol) of terephthalic acid dichloride and 3.57 g (0.021 mol) of isophthalic acid dichloride dissolved in 500 g of methylene chloride was placed in a dropping funnel and attached to the reaction vessel. The solution in the reaction vessel was stirred while maintaining the temperature at 20°C, and the methylene chloride solution was added dropwise from the dropping funnel over 60 minutes. Further, a solution of 0.71 g (0.005 mol) of benzoyl chloride dissolved in 10 g of methylene chloride was added thereto and stirred for 60 minutes. The resulting reaction solution was neutralized with an aqueous acetic acid solution, the pH of the aqueous phase was adjusted to 7, and the oil and aqueous phases were separated using a separatory funnel. The resulting oil phase was added dropwise to methanol under stirring to reprecipitate the polymer, and the precipitate was collected by filtration and dried in an oven at 80°C to obtain a white solid polyarylate resin. The yield was 11.5 g. The weight average molecular weight (Mw) of the resulting polyarylate resin was 33,780 and the number average molecular weight (Mn) was 8,130. The weight average molecular weight and number average molecular weight of the polyarylate resin were determined by gel permeation chromatography and expressed in terms of polystyrene.

[0165] 100 parts by mass of the polyarylate resin obtained above was added to a mixed solvent of 283 parts by mass of toluene and 283 parts by mass of o-xylene, and 1.1 parts by mass of comparative squarylium compound 1 as a near-infrared absorbing dye, 3.3 parts by mass of squarylium compound A shown below, 8 parts by mass of ultraviolet absorbing dye A, and 0.52 parts by mass of BYK-330 (polyether-modified polydimethylsiloxane) manufactured by BYK-Chemie KK as a surface conditioner were added and mixed uniformly to obtain resin composition 1.

[0166]

[0167] (3-2) Preparation of Resin Composition 2 24.7 parts by weight of 3-glycidoxypropyltrimethoxysilane (Dow-Toray, OFS-6040), 32.1 parts by weight of 2-propanol, and 3.4 parts by weight of distilled water were blended and mixed uniformly at 25 ° C., and then 1.54 parts by weight of formic acid was added and mixed for 90 minutes to allow the hydrolysis reaction of 3-glycidoxypropyltrimethoxysilane to proceed, thereby preparing a hydrolysis solution of the silane coupling agent. The resin composition 1 obtained above and the hydrolysis solution of the silane coupling agent were mixed uniformly at 25 ° C. in a mass ratio of 99:1, and the mixture was filtered through a 0.1 μm pore size filter (GL Sciences, GL Chromatodisc, non-aqueous 13N) to remove foreign matter, thereby obtaining a resin composition 2.

[0168] (3-3) Preparation of Resin Composition 3 Resin composition 3 was obtained in the same manner as in the preparation example of Resin Composition 1, except that squarylium compound 6 shown in Table 1 was used instead of squarylium compound A in the preparation example of Resin Composition 1.

[0169] (3-4) Preparation of Resin Composition 4 Resin composition 4 was obtained in the same manner as in the preparation example of Resin Composition 2, except that Resin Composition 3 was used instead of Resin Composition 1 in the preparation example of Resin Composition 2.

[0170] (4) Optical Filter (4-1) Preparation of Optical Filter Each resin composition obtained above was dropped in 2 cc onto a glass substrate (Schott, D263Teco), and then a spin coater (Mikasa, 1H-D7) was used to rotate the resin composition at 1600 rpm over 0.2 seconds, maintain the rotation speed for 20 seconds, and then reduce the rotation speed to 0 rpm over 0.2 seconds. The resin composition was then deposited on the glass substrate. The glass substrate on which the resin composition was deposited was initially dried at 100 ° C. for 3 minutes using a precision incubator (Yamato Scientific, DH611) (before curing). Thereafter, the atmosphere was substituted with nitrogen at 50 ° C. for 30 minutes using an inert oven (Yamato Scientific, DN610I), and then heated to 190 ° C. in about 15 minutes. The resin layer (absorption layer) was formed on the glass substrate by drying at 190 ° C. for 60 minutes under a nitrogen atmosphere (after curing). The thickness of the resin layer formed on the glass substrate was 2 μm. An optical filter was produced by forming a resin layer on the glass substrate in this manner. The thickness of the resin layer was determined by measuring the thickness of the glass substrate on which the resin layer was formed and the thickness of the glass substrate alone using a micrometer, and then calculating the difference between the two.

[0171] (4-2) Measurement of Transmission Spectrum For each optical filter having a resin layer formed on a glass substrate, the transmission spectrum was measured at a measurement interval of 1 nm using a spectrophotometer (Shimadzu Corporation, UV-1800), and the transmittance of light at wavelengths of 300 nm to 900 nm was determined. The transmission spectra were measured for the optical filters before and after curing of the resin layer. The results for the optical filter formed from resin composition 2 are shown in Figure 1, and the results for the optical filter formed from resin composition 4 are shown in Figure 2.

[0172] The squarylium compounds according to the present disclosure can be used, for example, in electronic components such as mobile phone cameras, digital cameras, in-vehicle cameras, surveillance cameras, and display elements (LEDs, etc.), as well as in security inks.

Claims

1. A squarylium compound represented by the following formula (1): [In formula (1), R １１ and R ２１ each independently represents an alkyl group which may have a substituent or an aralkyl group which may have a substituent; R １２ , R １３ , R ２２ and R ２３ each independently represents a hydrogen atom or an alkyl group; R １４ and R ２４ each independently represents a branched alkyl group having from 26 to 35 carbon atoms which may have a substituent, a group represented by the following formula (2), or a group represented by the following formula (3), １ and Ring A ２ each independently represents a 5- to 8-membered nitrogen-containing heterocycle, and the nitrogen-containing heterocycle is １１ and R ２１ may have a substituent other than the above.] [In formula (2), R ３１ is -C(=O)-R ３４ an acyl group represented by —SO ２ -R ３５ or a sulfonyl group-containing group represented by —Si(R ３６ ) (R ３７ ) (R ３８ ) and R ３４ ~R ３８ each independently represents an alkyl group which may have a substituent, an aryl group which may have a substituent, or an aralkyl group which may have a substituent; R ３２ and R ３３ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted aralkyl group; R ３２ ~R ３８ at least one of R is an optionally substituted linear alkyl group having 12 or more carbon atoms, an optionally substituted aryl group, or an optionally substituted aralkyl group, ３１ represents the same meaning as above, Ring B represents a hydrocarbon ring which may have a substituent and / or a fused ring structure, R ３４ ~R ３８ At least one of the groups is a linear alkyl group having 12 or more carbon atoms which may have a substituent, an aryl group which may have a substituent, or an aralkyl group which may have a substituent.] 2. The above R １４ and R ２４ 2. The squarylium compound according to claim 1, wherein: is a branched alkyl group having 26 to 35 carbon atoms which may have a substituent, and the branched alkyl group is branched at the carbon atom at the α-position.

3. In the formula (2), the R ３２ 2. The squarylium compound according to claim 1, wherein R represents an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted aralkyl group.

4. The above R １４ and R ２４ is a group represented by the formula (2), and ３１ contains the acyl group, and the R ３２ ~R ３４ At least one of R is a linear alkyl having 12 or more carbon atoms which may have a substituent, or １４ and R ２４ is a group represented by the formula (3), and ３１ contains the acyl group, and the R ３４ 2. The squarylium compound according to claim 1, wherein is an optionally substituted linear alkyl having 12 or more carbon atoms.

5. The above R １４ and R ２４ is a group represented by the formula (2), and ３１ contains the sulfonyl group-containing group, and the R ３２ , R ３３ and R ３５ At least one of R is a linear alkyl having 12 or more carbon atoms which may have a substituent, or １４ and R ２４ is a group represented by the formula (3), and ３１ contains the sulfonyl group-containing group, and the R ３５ 2. The squarylium compound according to claim 1, wherein is an optionally substituted linear alkyl having 12 or more carbon atoms.

6. The above R １４ and R ２４ is a group represented by the formula (2), and ３１ contains the silyl group, and the R ３２ , R ３３ and R ３６ ~R ３８ two or more of R are aryl groups which may have a substituent, or １４ and R ２４ is a group represented by the formula (3), and ３１ contains the silyl group, and the R ３６ ~R ３８ 2. The squarylium compound according to claim 1, wherein at least one of the groups is an aryl group which may have a substituent.

7. A resin composition comprising the scrillium compound according to any one of claims 1 to 6 and a resin component.

8. A molded article formed from the resin composition according to claim 7.

9. An optical filter having a resin layer formed from the resin composition according to claim 7.

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