JP2019031638A - Resin composition - Google Patents

Abstract

To provide a resin composition capable of exhibiting original optical characteristics of a squarylium compound which allow selective absorption of light in a red to near-infrared region while transmitting light in a visible light region at a high transmittance.SOLUTION: The resin composition contains a squarylium compound represented by formula (1) and a thermosetting resin. [Rto Rand Rto Rare each independently H, an organic group or a polar functional group; ring A and ring B are each independently a nitrogen-containing heterocyclic ring; and a substituted/unsubstituted branched alkyl group is bonded to N of the heterocyclic ring.]SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resin composition containing a squarylium compound, a cured product thereof, and an optical filter or sensor formed from these.

  The squarylium compound is useful as a dye having an absorption range in the red to near infrared region, and various types of squarylium compounds have been known so far. For example, Patent Documents 1 to 3 disclose a squarylium compound having a structure in which a benzene ring is bonded to both sides of a squarylium skeleton, and Patent Documents 4 and 5 include a heterocyclic ring bonded to both sides of a squarylium skeleton via a carbon atom. A squarylium compound having the structure is disclosed. Patent Document 6 discloses a squarylium compound having a structure in which a heterocycle is bonded to both sides of a squarylium skeleton via a carbon atom, and the carbon atom and the carbon atom constituting the heterocycle form a hydrocarbon ring. Yes.

International Publication No. 2014/088063 JP 2012-008532 A Japanese Patent Application Laid-Open No. 2015-086378 JP 2008-308602 A JP 2014-148567 A JP 2006-074649 A

  A squarylium compound cuts near-infrared light using a spectral characteristic that it can selectively absorb light in the red to near-infrared region while transmitting light in the visible region with high transmittance. It is expected to be used for near-infrared absorbing films and security inks. When the squarylium compound is applied to such a use, it is desirable to handle the squarylium compound as a resin composition, thereby improving the handleability of the squarylium compound and improving the workability. However, when the present inventors examined, a part of squarylium compound was mix | blended with a thermosetting resin, and when this was hardened | cured, it does not show the original spectral characteristic of a squarylium compound, but visible region (for example, wavelength) It became clear that there was a thing showing a new absorption peak in the range of 500 nm to 600 nm.

  The present invention has been made in view of the above circumstances, and an object of the present invention is a resin composition containing a squarylium compound and a thermosetting resin. An object of the present invention is to provide a resin composition capable of exhibiting the original optical characteristics of a squarylium compound that can selectively absorb light in the red to near-infrared region while transmitting at a high transmittance.

The present invention includes the following inventions.
[1] A resin composition comprising a squarylium compound represented by the following formula (1) and a thermosetting resin.

[In Formula (1),
R ^{1 to} R ³ and R ^{5 to} R ⁷ each independently represents a hydrogen atom, an organic group or a polar functional group,
Ring A and ring B each independently represent a nitrogen-containing heterocyclic ring, and a branched alkyl group which may have a substituent is bonded to the nitrogen atom of the heterocyclic ring. ]
[2] The resin composition according to [1], wherein the squarylium compound is represented by the following formula (2).

[In Formula (2),
R ^{1 to} R ³ and R ^{5 to} R ⁷ have the same meaning as above,
R ⁴ and R ⁸ represent a branched alkyl group which may have a substituent. ]

[3] R ¹ or R ² represents a group represented by the following formula (3), and R ⁵ or R ⁶ represents a group represented by the following formula (4). The resin composition as described.

—NH—C (═O) —R ⁹ (3)
—NH—C (═O) —R ¹⁰ (4)
[In Formula (3) and Formula (4), R ⁹ and R ¹⁰ each independently represents an alkyl group having 5 or more carbon atoms which may have a substituent. ]
[4] The resin composition according to any one of [1] to [3], wherein the thermosetting resin is an epoxy resin.
[5] A cured product obtained by curing the resin composition according to any one of [1] to [4].
[6] An optical filter comprising the resin composition according to any one of [1] to [4] or the cured product according to [5].
[7] A sensor comprising the optical filter according to [6].

  The resin composition of the present invention is an original material of a squarylium compound that can selectively absorb light in the red to near infrared region while transmitting light in the visible light region with high transmittance in the cured resin. Optical properties can be exhibited.

The absorption spectrum of the hardened | cured material of the resin composition containing the squarylium compound B examined in the Example is represented. The absorption spectrum of the hardened | cured material of the resin composition containing the comparison squarylium compound A examined in the Example is represented.

  The resin composition of the present invention contains a squarylium compound represented by the following formula (1) and a thermosetting resin.

In the above formula (1), R ^{1 to} R ³ and R ^{5 to} R ⁷ each independently represent a hydrogen atom, an organic group or a polar functional group, and Ring A and Ring B are each independently a nitrogen-containing heterocyclic ring. A branched alkyl group which may have a substituent is bonded to the nitrogen atom of the heterocyclic ring.

  The squarylium compound has a spectral characteristic of selectively absorbing light in the red to near infrared region and transmitting light in the visible light region with high transmittance. In particular, a squarylium compound in which a benzene ring in which a nitrogen-containing heterocycle is condensed to a squarylium skeleton as represented by the above formula (1) is bonded has a sharp absorption peak in the red to near infrared region. It becomes possible to selectively cut light in a wavelength region corresponding to this absorption peak.

  By the way, the present inventors have formulated a squarylium compound represented by the above formula (1) in which an alkyl group is bonded to the nitrogen atom of the nitrogen-containing heterocycle of ring A and ring B, and this is compounded in a thermosetting resin and cured. When the absorption (transmission) spectrum of the product is measured, the squarylium compound in which the linear alkyl group is bonded to the nitrogen atom of the nitrogen-containing heterocyclic ring of ring A and ring B, the visible light region (for example, wavelength) It became clear that there was a thing showing a new absorption peak in the range of 500 nm to 600 nm. In this case, it is difficult to exhibit the spectral characteristics inherent to the squarylium compound, that is, to selectively absorb light in the red to near-infrared region and transmit light in the visible light region with high transmittance. It is not preferable in that spectral design becomes difficult, such as when an optical filter is formed from a resin composition. Therefore, when various squarylium compounds were examined, by connecting a branched alkyl group instead of a linear alkyl group to the nitrogen atoms of the nitrogen-containing heterocycles of ring A and ring B, the original spectrum of the squarylium compound was obtained even in the cured resin. It became clear that the characteristics can be exhibited. Hereinafter, the resin composition of the present invention will be described in detail.

  The squarylium compound contained in the resin composition is represented by the above formula (1). The squarylium compound may have a compound having a resonance relationship. Examples of the compound having a resonance relationship with the squarylium compound of the formula (1) include compounds represented by the following formulas (1a) and (1b): Is mentioned. The squarylium compound of the present invention includes all these compounds having a resonance relationship. Specifically, the squarylium compound of the formula (1) includes a resonance relationship represented by the following formulas (1a) and (1b). Are included.

In the formula (1), groups bonded to one side and the other side of the squarylium skeleton may be the same as or different from each other. That is, R ¹ , R ² , R ³ and ring A may be the same as or different from R ⁵ , R ⁶ , R ⁷ and ring B, respectively. In the case where the groups bonded to one side and the other side of the squarylium skeleton are the same, the durability of the squarylium compound against heat and light can be expected. When the groups bonded to one side and the other side of the squarylium skeleton are different from each other, the association and aggregation of the molecules of the squarylium compound are suppressed, and an improvement in solubility in solvents and resins can be expected.

In formula (1), R < ¹ > -R < ³ >, R < ⁵ > -R < ⁷ > represents a hydrogen atom, an organic group, or a polar functional group each independently. Examples of the organic group represented by R ^{1 to} R ³ and R ^{5 to} R ⁷ include an alkyl group, an alkoxy group, an alkylthio group, an alkoxycarbonyl group, an alkylsulfonyl group, an alkylsulfinyl group, an aryl group, an aralkyl group, an aryloxy group, Examples thereof include an arylthio group, an aryloxycarbonyl group, an arylsulfonyl group, an arylsulfinyl group, a heteroaryl group, an amino group, an amide group, a sulfonamide group, a carboxy group (carboxylic acid group), and a cyano group. Examples of polar functional groups of R ^{1 to} R ³ and R ^{5 to} R ⁷ include a halogeno group, a hydroxyl group, a nitro group, and a sulfo group (sulfonic acid group).

Examples of the alkyl group for R ^{1 to} R ³ and R ^{5 to} R ⁷ include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, a pentyl group, a hexyl group, and a heptyl group. Linear or branched alkyl groups such as octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group A cyclic (alicyclic) alkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, and a cyclodecyl group; The alkyl group may have a substituent, and examples of the substituent that the alkyl group has include aryl group, heteroaryl group, halogeno group, hydroxyl group, carboxy group, alkoxy group, cyano group, nitro group, amino group, sulfo group. Groups and the like. Examples of the alkyl group having a halogeno group include a monohalogenoalkyl group, a dihalogenoalkyl group, an alkyl group having a trihalomethyl unit, and a perhalogenoalkyl group. As the halogeno group, a fluorine atom, a chlorine atom and a bromine atom are preferable, and a fluorine atom is particularly preferable. The number of carbon atoms of the alkyl group (the number of carbon atoms excluding substituents) is preferably 1-20, and specifically, if it is a linear or branched alkyl group, it preferably has 1-20 carbon atoms, more preferably 1-carbon. It is 10, More preferably, it is 1-5, C4-C10 is preferable if it is a cyclic alkyl group, and 5-8 are more preferable.

For specific examples of the alkyl group contained in the alkoxy group, alkylthio group, alkoxycarbonyl group, alkylsulfonyl group, and alkylsulfinyl group of R ^{1 to} R ³ and R ^{5 to} R ⁷ , refer to the description regarding the above alkyl group.

Examples of the aryl group represented by R ^{1 to} R ³ and R ^{5 to} R ⁷ 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 hydroxyl group, a cyano group, a nitro group, an amino group, Examples include thiocyanate group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, sulfo group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group and the like. 6-20 are preferable and, as for carbon number (carbon number except a substituent) of an aryl group, More preferably, it is 6-12.

Examples of the aralkyl groups of R ^{1 to} R ³ and R ^{5 to} R ⁷ 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, a halogeno group, a halogenoalkyl group, a cyano group, a nitro group, a thiocyanate group, an acyl group, and an alkoxycarbonyl group. Aryloxycarbonyl group, carbamoyl group, sulfo group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group and the like. 7-25 are preferable and, as for carbon number (carbon number except a substituent) of an aralkyl group, 7-15 are more preferable.

For specific examples of the aryl group contained in the aryloxy group, arylthio group, aryloxycarbonyl group, arylsulfonyl group, and arylsulfinyl group of R ^{1 to} R ³ and R ^{5 to} R ⁷ , refer to the description regarding the aryl group. The

Examples of the heteroaryl group of R ^{1 to} R ³ and R ^{5 to} R ⁷ include a thienyl group, a thiopyranyl group, an isothiochromenyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a pyridyl group, a pyralidinyl group, a pyrimidinyl group, and a pyridazinyl group. Group, thiazolyl group, isothiazolyl group, furanyl group, pyranyl group and the like. The heteroaryl group may have a substituent, and examples of the substituent that the heteroaryl group has include an alkyl group, an alkoxy group, an aryl group, a halogeno group, a halogenoalkyl group, a hydroxyl group, a cyano group, an amino group, and a nitro group. , Thiocyanate group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, sulfo group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group and the like. As for carbon number (carbon number except a substituent) of a heteroaryl group, 2-20 are preferable, More preferably, it is 3-15.

The amino groups of R ^{1 to} R ³ and R ^{5 to} R ⁷ are represented by the formula: —NR ^a1 R ^a2 , and R ^a1 and R ^a2 are each independently a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group. , Aryl groups, aralkyl groups, heteroaryl groups, and the like. For specific examples of the alkyl group, aryl group, aralkyl group, and heteroaryl group, the description of these groups is referred to above. As the alkenyl group and alkynyl group, one of the carbon-carbon single bonds of the alkyl group exemplified above is used. And groups in which a part is replaced with a double bond or a triple bond. R ^a1 and R ^a2 may be linked to each other to form a ring.

The amide group of R ^{1 to} R ³ and R ^{5 to} R ⁷ is represented by the formula: —NH—C (═O) —R ^a3 , where R ^a3 is an alkyl group, an aryl group, an aralkyl group, or a heteroaryl group. Some are listed. For specific examples of the alkyl group, aryl group, aralkyl group, and heteroaryl group, the description of these groups above is referred to.

The sulfonamide group of R ^{1 to} R ³ and R ^{5 to} R ⁷ is represented by the formula: —NH—SO ₂ —R ^a4 , and R ^a4 is an alkyl group, an aryl group, an aralkyl group, or a heteroaryl group Etc. For specific examples of the alkyl group, aryl group, aralkyl group, and heteroaryl group, the description of these groups above is referred to.

Examples of the halogeno group for R ^{1 to} R ³ and R ^{5 to} R ⁷ include a fluoro group, a chloro group, a bromo group, and an iodo group.

R ^{1 to} R ³ and R ^{5 to} R ^{7 in} Formula (1) are each independently preferably a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, an amide group, or a hydroxyl group. Such a squarylium compound is relatively easy to manufacture, and the maximum absorption wavelength of the squarylium compound can be controlled to a desired wavelength range by appropriately selecting R ^{1 to} R ³ and R ^{5 to} R ^7. It becomes. Especially, it is preferable that R < ¹ > -R < ³ >, R < ⁵ > -R < ⁷ > is respectively independently a hydrogen atom, an alkyl group, or an amide group from the point of stability of a squarylium compound and manufacture ease. In this case, the alkyl group is preferably linear or branched, and the carbon number thereof is preferably 1 to 6, more preferably 1 to 4, and still more preferably 1 to 3.

  The nitrogen-containing heterocycle of the ring A and the ring B in the formula (1) has at least one nitrogen atom as a hetero atom constituting the ring, and a branched alkyl group is bonded to this nitrogen atom. For example, when a linear alkyl group is bonded to the nitrogen atoms constituting Ring A and Ring B, the squarylium compound originally shows in the cured product of the resin composition in which the squarylium compound is blended with the thermosetting resin. A new absorption peak may be shown in the visible light region (for example, a wavelength range of 500 nm to 600 nm), which is different from the absorption peak, but a branched alkyl group is bonded to the nitrogen atoms constituting Ring A and Ring B. Therefore, the spectral characteristics inherent to the squarylium compound can be exhibited even in the cured product of the thermosetting resin. The cause of such a difference in the absorption spectrum depending on the type of alkyl group bonded to the nitrogen atom constituting ring A and ring B is not clear, but if the alkyl group is linear, a thermosetting resin During the curing reaction, the squarylium compound forms an aggregate and is fixed in that state, so that it is considered that a new absorption peak that has not been seen with the squarylium compound alone appears.

  The branched alkyl group bonded to the nitrogen atoms constituting ring A and ring B is not particularly limited as long as it has 3 or more carbon atoms. Examples of the branched alkyl group include isopropyl group, isobutyl group, tert-butyl group, isopentyl group, sec-pentyl group, 1-ethylpropyl group, neopentyl group, tert-pentyl group, isohexyl group, sec-hexyl group, 2- Examples thereof include a methylpentyl group, a 3-methylpentyl group, a tert-hexyl group, and a 2-ethylhexyl group. The upper limit of the carbon number of the branched alkyl group (the number of carbon atoms excluding the substituent) is not particularly limited, but is preferably 20 or less, more preferably 12 or less, still more preferably 8 or less, and even more preferably 6 or less. The branched alkyl group bonded to the nitrogen atom constituting ring A and ring B may have a substituent, and examples of the substituent include an aryl group, a heteroaryl group, a halogeno group, a hydroxyl group, a carboxy group, A cyano group, a nitro group, a sulfo group, etc. are mentioned. The branched alkyl group preferably has no substituent.

  The nitrogen-containing heterocycle of ring A and ring B may have only one nitrogen atom as a ring constituent atom, or may have two or more heteroatoms. When it has two or more heteroatoms, it has at least one nitrogen atom, and at least one atom selected from N (nitrogen atom), S (sulfur atom), and O (oxygen atom). Have one or more. Examples of the nitrogen-containing heterocycle of ring A and ring B include a pyrrolidine ring, a piperidine ring, a hexamethyleneimine ring, a heptamethyleneimine ring, a morpholine ring, a thiomorpholine ring, and a piperazine ring. From the viewpoint of ease of production of the squarylium compound, the nitrogen-containing heterocycle of ring A and ring B preferably has only one nitrogen atom as a hetero atom constituting the ring. Ring A and ring B are preferably non-aromatic nitrogen-containing heterocycles, and except for a carbon-carbon bond condensed with a benzene ring, a carbon atom and a nitrogen atom or carbon atoms are bonded by a single bond. It is more preferable that the ring is formed.

In the nitrogen-containing heterocycle of ring A and ring B, it is preferable that a nitrogen atom is bonded to the carbon atom at the para position of the bond position of the squarylium skeleton of the benzene ring to which ring A or ring B is condensed. That is, as a squarylium compound contained in a resin composition, what is represented by following formula (2) is preferable. In the following formula (2), R ^{1 to} R ³ and R ^{5 to} R ⁷ represent the same meaning as described above, and R ⁴ and R ⁸ are the branched alkyl which may have a substituent as described above. Represents a group. With such a squarylium compound, the maximum absorption peak of the absorption spectrum is shifted to the long wavelength side (for example, 685 nm or more), the transmittance of light in the red region is increased, and the color of the transmitted light is made actual. It becomes easy to get closer.

  The nitrogen-containing heterocycle of ring A and ring B may have a substituent other than the branched alkyl group described above. That is, in the nitrogen-containing heterocycle of ring A and ring B, a substituent may be bonded to a ring constituent atom other than the nitrogen atom, and examples of such substituent include the organic group and polar functional group described above. Can be mentioned. Among them, the substituents that ring A and ring B may have (excluding the substituent bonded to the nitrogen atom constituting ring A or ring B) include an alkyl group, an alkoxy group, an aryl group, and an aralkyl group. , A halogeno group, a halogenoalkyl group and a hydroxyl group are preferred, and an alkyl group, an aryl group, an aralkyl group and a halogenoalkyl group are 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 carbon atoms, still more preferably 1 to 3 carbon atoms, and the aryl group has 6 to 12 carbon atoms. Preferably, 6 to 10 is more preferable, and the number of carbon atoms of the aralkyl group is preferably 7 to 13, and more preferably 7 to 11. The alkyl group may be linear or branched. Ring A and ring B may not have a substituent other than the branched alkyl group bonded to the ring nitrogen atom.

  The number of ring members of ring A and ring B is preferably 5 or more, more preferably 6 or more, 12 or less, more preferably 10 or less, and even more preferably 8 or less. In particular, if the number of ring members in ring A and ring B is 6 or more, the absorption peak having the maximum absorption in the red to near infrared region can be made particularly sharp, and the inclined part on the short wavelength side of the absorption peak Can be absorbed. Therefore, the boundary between the transmission wavelength region and the absorption wavelength region is sharply formed, and light in the wavelength region corresponding to the absorption peak can be selectively cut.

  As the squarylium compound in which ring A and ring B are 5-membered or more nitrogen-containing heterocycles, a squarylium compound represented by the following formula (5) is preferably shown.

In the formula (5), R ^{1 to} R ⁸ are as described above, R ¹¹ represents a hydrogen atom or a substituent bonded to the carbon atom constituting the ring A, and R ¹² represents the ring B A hydrogen atom or a substituent bonded to the constituent carbon atom is represented, and m and n represent an integer of 1 or more. A plurality of R ¹¹ may be independently identical or different from each other, a plurality of R ¹² may be the same or different from each other. In the squarylium compound of formula (5), ring A and ring B are 5-membered or higher heterocycles having only one nitrogen atom as a hetero atom, except for a carbon-carbon bond condensed with a benzene ring, A carbon atom and a nitrogen atom or carbon atoms are bonded by a single bond to form a ring.

In the formula (5), examples of the substituent for R ¹¹ and R ¹² include the organic groups and polar functional groups described above. m and n are preferably 2 or more, preferably 8 or less, more preferably 6 or less, and still more preferably 4 or less.

R ¹¹ and R ¹² are preferably each independently 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, a halogenoalkyl group, and a hydroxyl group. More preferably a group or an atom selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, and a halogenoalkyl group, and a group selected from the group consisting of a hydrogen atom, an alkyl group, and a halogenoalkyl group Or it is more preferable that it is an atom. 1-8 are preferable, as for carbon number of the alkyl group and halogenoalkyl group in this case, 1-5 are more preferable, and 1-3 are more preferable. Among them, R ¹¹ and R ¹² are preferably hydrogen atoms, that is, ring A and ring B preferably have no substituent other than R ⁴ and R ⁸ .

In the squarylium compound, R ¹ or R ² is preferably a group represented by the following formula (3), and R ⁵ or R ⁶ is preferably a group represented by the following formula (4). In the following formula (3) and the following formula (4), R ⁹ and R ¹⁰ each independently represents an alkyl group having 5 or more carbon atoms which may have a substituent. Such squarylium compounds are excellent in solubility in organic solvents and resins. Therefore, it becomes possible to contain the squarylium compound in the resin composition at a high concentration, and even when the optical filter is formed from the resin composition, even if the thickness is formed thin, it is derived from the squarylium compound. Light in the near infrared region can be suitably absorbed.
—NH—C (═O) —R ⁹ (3)
—NH—C (═O) —R ¹⁰ (4)

The number of carbon atoms (the number of carbon atoms excluding the substituent) of R ⁹ and R ¹⁰ is preferably 6 or more, more preferably 7 or more, and even more preferably 8 or more from the viewpoint of increasing the solubility in organic solvents and resins. The upper limit of the carbon number of the alkyl group of R ⁹ and R ¹⁰ is not particularly limited, but is preferably 30 or less, more preferably 25 or less, still more preferably 20 or less, and even more preferably 18 or less. Examples of the alkyl group of R ⁹ and R ¹⁰ include pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, An octadecyl group, a nonadecyl group, an icosyl group, etc. are mentioned.

The alkyl group of R ⁹ and R ¹⁰ may have a substituent, and examples of the substituent include an aryl group, heteroaryl group, halogeno group, hydroxyl group, carboxy group, cyano group, nitro group, amino group, sulfo group. Groups and the like. The alkyl group of R ⁹ and R ¹⁰ preferably does not have a substituent.

The alkyl groups of R ⁹ and R ¹⁰ are preferably linear. When R ⁹ and R ¹⁰ are linear alkyl groups, the heat resistance of the squarylium compound tends to increase, and the decomposition of the squarylium compound can be suppressed when the squarylium compound is blended with a resin and cured by heating. Therefore, the squarylium compound can be present at a high concentration even in the cured resin that has undergone the heat treatment.

Squarylium compounds, from the viewpoint of easy production, more preferably R ¹ is a group represented by the formula (3), and more preferably R ⁵ is a group represented by the formula (4) . In this case, R ² , R ³ , R ⁶ and R ⁷ are preferably not an amide group, for example, preferably a hydrogen atom or an alkyl group.

As the squarylium compound in which R ¹ is a group represented by the formula (3) and R ⁵ is a group represented by the formula (4), a squarylium compound represented by the following formula (6) is preferably shown. . In the following formula (6), R ^{2 to} R ⁴ , R ^{6 to} R ¹⁰ , ring A and ring B are as described above.

  The squarylium compound represented by the formula (6) is relatively easy to produce and has excellent solubility in organic solvents and resins. Therefore, it becomes possible to contain the squarylium compound in the resin composition at a high concentration, and even when the optical filter is formed from the resin composition, even if the thickness is formed thin, it is derived from the squarylium compound. Light in the near infrared region can be suitably absorbed. Moreover, when using a squarylium compound for a security ink etc., a squarylium compound can be contained in high concentration in an ink, and the coloring property of an ink can be improved. Furthermore, among the cured products of the thermosetting resin composition, according to the original absorption spectrum of the squarylium compound, it selectively absorbs light in the red to near infrared region while transmitting light in the visible light region with high transmittance. Is possible.

As the squarylium compound contained in the resin composition of the present invention, a squarylium compound represented by the following formula (7) is particularly preferred. In the following formula (7), R ^{2 to} R ⁴ , R ^{6 to} R ¹² , ring A, ring B, m, and n are referred to the above description.

The squarylium compound demonstrated above can be manufactured by making the compound of a following formula (8-1), and the compound of a following formula (8-2) react with squaric acid. In the following formulas (8-1) and (8-2), R ^{1 to} R ³ , R ^{5 to} R ⁷ , ring A and ring B have the same meanings as in the above formula (1), and preferred The aspect is also as described above. The compound of formula (8-1) and the compound of formula (8-2) may be the same.

  The reaction between squaric acid and the above compound is preferably carried out in the presence of a solvent. Solvents that can be used include, for example, chlorinated hydrocarbons such as chloroform and methylene chloride; aromatic hydrocarbons such as benzene, toluene, xylene and trimethylbenzene; chlorinated aromatics such as chlorotoluene and dichlorobenzene; tetrahydrofuran (THF), dioxane, cyclopentyl methyl ether, diisopropyl ether, diethyl ether and other ethers; methanol, ethanol, propanol, butanol and other alcohols; and the like. These solvents may use only 1 type and may use 2 or more types together.

  In the reaction with squaric acid, the reaction temperature may be appropriately set. For example, 30 ° C or higher is preferable, 60 ° C or higher is more preferable, 80 ° C or higher is more preferable, 170 ° C or lower is preferable, and 140 ° C or lower is more preferable. . The reaction is preferably performed under reflux. The reaction time is not particularly limited and may be appropriately set according to the progress of the reaction. For example, 0.5 hour or more is preferable, 1 hour or more is more preferable, 48 hours or less is preferable, and 24 hours or less is preferable. More preferred. The atmosphere during the reaction is preferably an inert gas (nitrogen, argon, etc.) atmosphere.

  The production of squarylium compounds can also be referred to the following article: Serguei Miltsov et al., “New Cyanine Dyes: Norindosquarocyanines”, Tetrahedron Letters, Vol. 40, Issue 21, p. 4067-4068 (1999).

  The obtained squarylium compound can be appropriately purified by known purification means such as filtration, silica gel column chromatography, alumina column chromatography, sublimation, recrystallization, and crystallization as necessary. The chemical structure of the squarylium compound can be analyzed by known analysis methods such as mass spectrometry, single crystal X-ray structure analysis, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy.

  The thermosetting resin used for the resin composition of the present invention will be described. The thermosetting resin is not particularly limited as long as the resin component undergoes a polymerization reaction upon heating and is cured. Epoxy resin, phenol resin, polyurethane resin, melamine resin, urea resin, unsaturated polyester resin, silicone resin, diallyl Examples include phthalate resins and vinyl ester resins. Especially, as a thermosetting resin, it is preferable to use an epoxy resin from the point that heat resistance is high and the shape stability under high temperature is excellent.

  The oxirane compound contained in the epoxy resin may contain an epoxy group (oxirane ring) in the form of a glycidyl group, and an alicyclic epoxy group (cycloalkene oxide) obtained by oxidizing and epoxidizing a double bond of a cycloalkylene ring. ) May be included. When the epoxy group is included in the form of a glycidyl group, the glycidyl group may be present, for example, in the form of a glycidyl ether, may be present in the form of a glycidyl amine, or may be present in the form of a glycidyl ester. Of course, the glycidyl group may be directly bonded to the main chain.

  The epoxy resin includes an aromatic epoxy resin having an aromatic ring structure in the main chain, an alicyclic epoxy resin having an alicyclic structure, an aliphatic hydrocarbon chain structure having neither an aromatic ring structure nor an alicyclic structure in the main chain. The aliphatic epoxy resin which has can be used, and the kind in particular is not limited.

  Examples of the aromatic epoxy resin include oxirane compounds having a bisphenol skeleton, a fluorene skeleton, a biphenyl skeleton, a naphthalene ring, an anthracene ring, etc. in the main chain, and these compounds usually contain an epoxy group in the form of a glycidyl group. Examples of the aromatic epoxy resin include bisphenol type epoxy resin; biphenyl type epoxy resin; polyfunctional glycidyl amine resin such as tetraglycidylaminodiphenylmethane; polyfunctional glycidyl ether resin such as tetraphenyl glycidyl ether ethane; phenol novolac type epoxy. Resin; Cresol novolak type epoxy resin; Reaction product of polyphenol compound obtained by condensation reaction of phenolic compound such as phenol, o-cresol, m-cresol, naphthol and aromatic aldehyde having phenolic hydroxyl group and epichlorohydrin; A polyphenol compound obtained by an addition reaction between a phenol compound and a diolefin compound such as divinylbenzene or dicyclopentadiene, and epichlorohydrin Applied Physics, and the like.

  Examples of the alicyclic epoxy resin include oxirane compounds having an alicyclic structure such as a cyclohexane ring, and the epoxy group is included in the form of a glycidyl group or a cycloalkene oxide. Examples of the alicyclic epoxy resin having a glycidyl group include those having an alicyclic structure in the main chain, such as those obtained by hydrogenating the aromatic ring of the above aromatic epoxy resin (hydrogenated epoxy resin), 2 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2-bis (hydroxymethyl) -1-butanol and the like. Examples of the alicyclic epoxy resin having a cycloalkene oxide structure include 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, epsilon-caprolactone-modified-3,4-epoxycyclohexylmethyl-3 ′, 4. Examples include '-epoxycyclohexanecarboxylate, bis- (3,4-epoxycyclohexyl) adipate, and the like.

  Examples of the aliphatic epoxy resin include oxirane compounds having a propylene glycol structure, an alkylene structure, an oxyalkylene structure, etc. in the main chain, and these compounds usually contain an epoxy group in the form of a glycidyl group. Examples of the aliphatic epoxy resin include polyhydroxy compounds (ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol (PEG 600), propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, polypropylene glycol ( PPG), glycerol, diglycerol, tetraglycerol, polyglycerol, trimethylolpropane and its multimers, pentaerythritol and its multimers, mono / polysaccharides such as glucose, fructose, lactose, maltose, etc.) and epihalohydrin Can be obtained.

  It is preferable to use an alicyclic epoxy resin as the epoxy resin. If an alicyclic epoxy resin is used, it becomes easy to improve the heat resistance of a resin cured material, and it can make it a thing with little coloring.

  The oxirane compound contained in the epoxy resin preferably contains an epoxy group (oxirane ring) in the form of a glycidyl group. Epoxy resins are usually handled as a resin composition containing a curing agent and a curing catalyst, but if an epoxy resin having a glycidyl group is used, various types of curing agents and curing catalysts can be used for curing. In addition, the scope of application as a resin composition can be expanded by appropriately selecting a curing agent and a curing catalyst. More preferably, the oxirane compound contained in the epoxy resin contains 3 or more epoxy groups (oxirane rings) in one molecule (polyfunctional type).

  The resin composition containing an epoxy resin preferably contains a curing agent and / or a curing catalyst. A well-known thing can be used for a hardening | curing agent and a hardening catalyst, and what is necessary is just to select suitably according to the kind and desired property of an epoxy resin. Curing agents include amines (aliphatic diamines, aliphatic polyamines, alicyclic diamines, alicyclic polyamines, aromatic diamines, aromatic polyamines, etc.), polyaminoamides, acid anhydrides (aliphatic acid anhydrides). Alicyclic acid anhydrides, aromatic acid anhydrides, etc.), phenols (bisphenol, polyphenols, etc.), polymercaptans and the like. As the curing catalyst, tertiary amines (tris (dimethylaminomethyl) phenol, dimethylbenzylamine, 1,8-diazabicyclo (5.4.0) undecane, 1,5-diazabicyclo (4.3.0) -nonene -5), imidazoles (1-cyanoethyl-2-ethyl-4-methylimidazole, 2-ethyl-4-methylimidazole, etc.), Lewis acid salts and Bronsted acid salts. Only one type of curing agent and curing catalyst may be used, or two or more types may be used in combination. The curing agent and the curing catalyst may be used in a total amount of, for example, 0.1 to 10 parts by mass with respect to 100 parts by mass of the epoxy resin.

  A latent curing catalyst is preferably used as the curing agent. Examples of the latent curing catalyst include a thermal latent curing catalyst and a photolatent curing catalyst, and there are a cationic curing catalyst and a radical curing catalyst depending on the reaction type. Even if the latent curing catalyst is contained in the resin composition together with the epoxy resin, the latent curing catalyst can be stably stored for a long period of time if it does not trigger heat or light reaction initiation. Handleability is improved. If it is a heat-latent curing catalyst, the curing reaction proceeds by heating the resin composition, and if it is a photo-latent curing catalyst, the curing reaction proceeds by irradiating the resin composition with active energy rays. Thus, when a latent curing catalyst is used as a curing agent, the curing reaction of the epoxy resin can be freely adjusted, and even when prepared as a one-component resin composition, it has excellent storage stability and is desired to be cured. Can promptly advance the curing reaction by giving a reaction trigger by heating or irradiation with active energy rays. Especially, it is preferable to use a heat latent cationic curing catalyst or a photolatent cationic curing catalyst from the viewpoint that the shrinkage amount of the cured product can be reduced.

As the heat latent cationic curing catalyst, a known catalyst may be used as appropriate, and among them, a salt of an organic borane and a Lewis base is preferably used. It is also preferable to use a salt of an organic borane and a Lewis base. The organic borane functions as a Lewis acid, and for example, those represented by the following formula (9) are preferably used. By using such a heat-latent cationic curing catalyst, it becomes easy to obtain a cured product having excellent durability such as heat resistance and moisture resistance and reduced coloring.
BR ^b1 _u R ^b2 _3-u (9)

In the above formula (9), R ^b1 represents a fluorophenyl group, R ^b2 represents a hydrocarbon group which may have a substituent, and u represents an integer of 1 to 3. In the fluorinated phenyl group of R ^b1 , the hydrogen atom of the phenyl group is substituted with 1 to 5 fluorine atoms. If R ^b1 have more than one plurality of R ^b1 may be the same or different and if R ^b2 have more than one plurality of R ^b2 may be the same or different. The hydrocarbon group for R ^b2 preferably has 1 to 20 carbon atoms, and is preferably an alkyl group, an aryl group, or an alkenyl group. Examples of the substituent that these groups may have include a halogen atom, a hydroxyl group, an alkyl group, an aryl group, an alkenyl group, and an alkoxy group.

  Specific examples of the organic borane (Lewis acid) represented by the above formula (9) include, for example, tris (pentafluorophenyl) borane (hereinafter referred to as “TPB”), bis (pentafluorophenyl) phenylborane, penta Fluorophenyl-diphenylborane, tris (4-fluorophenyl) borane and the like are preferable. Among these, TPB is more preferable because it can improve the heat resistance, moist heat resistance, temperature impact resistance, and the like of the cured product. A catalyst containing TPB as a Lewis acid is referred to as a “TPB catalyst”.

  The Lewis base used as the counter ion of the organic borane is not limited as long as it can form a coordinate bond with the boron atom of the organic borane, and those commonly used as Lewis bases can be used, and have an unshared electron pair. A compound having an atom is preferably used. Specifically, a compound having a nitrogen atom, a phosphorus atom or a sulfur atom can be used. In this case, the Lewis base can form a coordination bond by donating a non-shared electron pair possessed by a nitrogen atom, a phosphorus atom, or a sulfur atom to a boron atom of an organic borane.

Examples of the salt of organic borane and Lewis base include organic borane / amine such as TPB / monoalkylamine complex, TPB / dialkylamine complex, TPB / alkylamine complex such as TPB / trialkylamine complex, and TPB / hindered amine complex. Complex: Organic borane / ammonia complex such as TPB / NH ₃ complex; Organic borane / phosphine complex such as TPB / triarylphosphine complex, TPB / diarylphosphine complex, TPB / monoarylphosphine complex; Organic such as TPB / alkylthiol complex Examples include borane / thiol complexes; organic borane / sulfide complexes such as TPB / diaryl sulfide complexes and TPB / dialkyl sulfide complexes. Among these, TPB / alkylamine complexes, TPB / hindered amine complexes, TPB / NH ₃ complexes, and TPB / phosphine complexes are preferably used.

  Examples of the photolatent cationic curing catalyst include triphenylsulfonium hexafluoroantimonate, triphenylsulfonium phosphate, p- (phenylthio) phenyldiphenylsulfonium hexafluoroantimonate, p- (phenylthio) phenyldiphenylsulfonium hexafluorophosphate, 4 -Chlorophenyldiphenylsulfonium hexafluorophosphate, 4-chlorophenyldiphenylsulfonium hexafluoroantimonate, bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluorophosphate, bis [4- (diphenylsulfonio) phenyl] sulfide Bishexafluoroantimonate, (2,4-cyclopentadien-1-yl) [(1-methyl ester Le) benzene] -Fe- hexafluorophosphate, diaryliodonium hexafluoroantimonate, and the like. Among these, it is preferable to use an onium salt, and it is preferable to use at least one of a triarylsulfonium salt and a diaryliodonium salt.

  The resin composition of the present invention contains at least the squarylium compound and the thermosetting resin described above, and the squarylium compound contained in the resin composition may be only one type or two or more types. There may be.

  Although the squarylium compound can be regarded as a kind of dye, the resin composition of the present invention is not limited to the squarylium compound represented by the above formula (1) as long as the desired performance according to the application is ensured. May be contained. Examples of the dye that may be contained in the resin composition include a squarylium dye other than the squarylium compound represented by the above formula (1), a croconium dye, copper (for example, Cu (II)) or zinc as a central metal ion. (For example, Zn (II)) cyclic tetrapyrrole dyes (porphyrins, chlorins, phthalocyanines, cholines, etc.), cyanine dyes, quaterylene dyes, naphthalocyanine dyes, nickel Examples thereof include complex dyes, copper ion dyes, diimmonium dyes, subphthalocyanine dyes, xanthene dyes, azo dyes, and dipyrromethene dyes. These other pigments may be used alone or in combination of two or more. Among these, it is preferable to use a combination of the squarylium compound of the formula (1) and the squarylium compound disclosed in JP-A-2006-074649 (the squarylium compound represented by the following formula (10)). It becomes easy to form a resin composition having a wide absorption wavelength region in the outer region and having a high transmittance in a wide range of the visible light region on the shorter wavelength side.

In the above formula (10), R ²¹ and R ²² each independently represent a group represented by the following formula (11). In the following formula (11), the ring P is a 4-9 membered unsaturated carbonization. Represents a hydrogen ring, ring Q represents an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocyclic ring which may have a substituent, or a condensed ring containing these ring structures; R ²³ represents a hydrogen atom, an organic group or a polar functional group, R ²⁴ represents an organic group or a polar functional group, and * represents a bonding site with a 4-membered ring (squarylium skeleton) in formula (10). , K is an integer of 0 to 6 and is less than or equal to h (where h is a value obtained by subtracting 3 from the number of members of ring P), and when k is 2 or more, a plurality of R ²⁴ are the same Or different.

For details of the organic group and polar functional group of R ²³ and R ²⁴ , refer to the description of the organic group and polar functional group of R ^{1 to} R ³ and R ^{5 to} R ⁷ . R ²³ is preferably a hydrogen atom, an alkyl group, an alkoxycarbonyl group or an aryl group, more preferably an alkyl group or an aryl group. In this case, the number of carbon atoms of the alkyl group is preferably 1 to 6 if it is a linear or branched alkyl group, more preferably 1 to 4, and 4 to 7 if it is an alicyclic alkyl group. Preferably, it is 5-6. 6-10 are preferable and, as for carbon number of an aryl group, More preferably, it is 6-8. When R ²³ is an alkyl group or an aryl group, a methyl group, an ethyl group, an isopropyl group, an isobutyl group, a t-butyl group, a cyclopentyl group, a cyclohexyl group, a phenyl group and the like are preferable. R ²⁴ is preferably an alkyl group, an alkoxy group, a halogeno group, an aryl group, an alkoxycarbonyl group (ester group), an amide group, a sulfonamide group, or a hydroxyl group, more preferably an alkyl group or a hydroxyl group. Preferable examples include linear or branched alkyl groups having 1 to 4 carbon atoms. Ring P preferably has no substituent R ²⁴ , that is, k is preferably 0.

  As the structure of the ring P, for example, cyclobutene, cyclopentene, cyclopentadiene, cyclohexene, cyclohexadiene, cycloheptene, cycloheptadiene, cycloheptatriene, cyclooctene, cyclooctadiene, cyclooctatriene, cyclononene, cyclononadiene, cyclononatriene, Examples include cycloalkene structures such as cyclononatetraene. Of these, cycloalkane monoenes such as cyclopentene, cyclohexene, cycloheptene, and cyclooctene are preferable, and cyclohexene, cycloheptene, and cyclooctene are more preferable.

  Examples of the aromatic hydrocarbon ring of ring Q include a benzene ring, a naphthalene ring, a phenanthrene ring, an anthracene ring, a fluoranthene ring, a cyclotetradecaheptaene ring, and the like. The aromatic hydrocarbon ring may have only one ring structure or may be a condensation of two or more ring structures. The aromatic heterocyclic ring of ring Q includes one or more atoms selected from N (nitrogen atom), O (oxygen atom) and S (sulfur atom) in the ring structure, and has aromaticity. , Furan ring, thiophene ring, pyrrole ring, pyrazole ring, oxazole ring, thiazole ring, imidazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, purine ring, pteridine ring and the like. The aromatic heterocycle may have only one ring structure, or may be a condensation of two or more ring structures. The condensed ring containing these ring structures of the ring Q has a structure in which an aromatic hydrocarbon ring and an aromatic heterocyclic ring are condensed. For example, an indole ring, an isoindole ring, a benzimidazole ring, a quinoline ring Benzopyran ring, acridine ring, xanthene ring, carbazole ring and the like.

  Ring Q may have a substituent, and examples of the substituent include the organic groups and polar functional groups described above. Among them, an alkyl group (preferably a linear or branched alkyl group having 1 to 4 carbon atoms), an aryl group, an alkoxy group (preferably an alkoxy group having 1 to 4 carbon atoms), an alkylthio group (preferably 1 carbon atom). ~ 2 alkylthio groups), heteroaryl groups, amino groups, amide groups, sulfonamido groups, hydroxyl groups, thiol groups, benzothiazole groups, indolinyl groups and the like; halogeno groups (preferably fluoro groups, chloro groups) , Bromo group), halogenoalkyl group (preferably perhalogenoalkyl group having 1 to 3 carbon atoms), cyano group, alkoxycarbonyl group (ester group), carboxy group (carboxylic acid group), carboxylic acid ester group, carboxylic acid amide Preferred examples include electron-withdrawing groups such as a group, a sulfo group (sulfonic acid group), and a nitro group. Among these, an electron withdrawing group is more preferable, and a halogeno group is particularly preferable. Ring Q may not have a substituent. When the ring Q has a substituent, the number is preferably 1 to 3, more preferably 1 to 2, and still more preferably 1.

  Specific examples of the squarylium compound represented by the formula (10) include squarylium compound 01 to squarylium compound 30 described in Examples of JP-A-2006-074649. As the squarylium compound represented by the formula (10), the ring P is preferably a cyclohexene ring or a cyclooctene ring, more preferably a cyclooctene ring, and the ring Q may have a substituent. A benzene ring or an optionally substituted naphthalene ring is preferred. For details of the squarylium compound represented by the formula (10), refer to the description of JP-A-2006-074649.

  The content of the squarylium compound in the resin composition (when two or more squarylium compounds are used, the total content thereof) is 0 in 100% by mass of the solid content of the resin composition from the viewpoint of expressing desired performance. It is preferably 0.01% by mass or more, more preferably 0.3% by mass or more, and further preferably 1% by mass or more. Moreover, from the point which improves the moldability, film formability, etc. of the resin composition, the content of the squarylium compound in the resin composition is preferably 25% by mass or less in 100% by mass of the solid content of the resin composition, and 20% by mass. % Or less is more preferable, and 15% by mass or less is more preferable. When the resin composition also contains a dye other than the squarylium compound, the total content thereof is preferably in the above range. By adjusting the content of the squarylium compound in the resin composition in this way, when forming a resin layer from the resin composition to form an optical filter, while transmitting light in the visible light region with high transmittance, It becomes easy to selectively absorb light in the red to near-infrared region.

  When the squarylium compound of the formula (1) and the squarylium compound of the formula (10) are used in combination, the content of the squarylium compound of the formula (1) is the squarylium compound of the formula (1) and the squarylium of the formula (10). 20 mass% or more is preferable with respect to a total of 100 mass% with a compound, 30 mass% or more is more preferable, 80 mass% or less is preferable, and 70 mass% or less is more preferable.

  When the resin composition also contains a dye other than the squarylium compound, the content of the other dye is preferably 100 parts by mass or less, more preferably 60 parts by mass or less, with respect to 100 parts by mass of the squarylium compound. More preferred is less than or equal to parts by weight.

  The thermosetting resin contained in the resin composition is preferably a highly transparent resin, which facilitates the application of the resin composition to optical applications. For example, the thermosetting resin preferably has a total light transmittance of 75% or more at a thickness of 0.1 mm, more preferably 80% or more, and still more preferably 85% or more. The upper limit of the total light transmittance is not particularly limited, and the total light transmittance may be 100% or less, but may be 95% or less, for example. The total light transmittance is measured based on JIS K 7105.

  The resin composition may contain a solvent or may be a paint. The resin composition formed into a paint can be easily applied by including a solvent. The resin composition formed into a paint can be obtained, for example, by dissolving the squarylium compound in a solvent containing a thermosetting resin or by dispersing the squarylium compound in a solvent (dispersion medium) containing a thermosetting resin. The solvent may function as a solvent (solvent) for the squarylium compound or may function as a dispersion medium. Examples of the solvent include ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; glycol derivatives such as PGMEA (2-acetoxy-1-methoxypropane), ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, and ethylene glycol ethyl ether acetate (Ether compounds, ester compounds, ether ester compounds, etc.); amides such as N, N-dimethylacetamide; esters such as ethyl acetate, propyl acetate, butyl acetate; N-methyl-pyrrolidone (specifically 1 -Pyrrolidones such as methyl-2-pyrrolidone); aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as cyclohexane and heptane; tetrahydrofuran, dioxane, diethyl ether, di Ethers such as Chirueteru; and the like. These solvents may use only 1 type and may use 2 or more types together.

  The content of the solvent is preferably 50% by mass or more, for example, preferably 70% by mass or more, more preferably less than 100% by mass, and more preferably 95% by mass or less, in 100% by mass of the resin composition. By adjusting the content of the solvent within such a range, it becomes easy to obtain a resin composition having a high squarylium compound concentration.

  It should be noted that amides such as N, N-dimethylacetamide and the like may decompose the squarylium compound, so that the amount used is preferably small. Therefore, the content of amides is preferably 60% by mass or less, more preferably 40% by mass or less, further preferably 20% by mass or less, still more preferably 5% by mass or less, and further preferably 0% by mass in 100% by mass of the resin composition. % Is particularly preferred (ie does not include amides).

  The resin composition may contain, for example, a compound (ultraviolet absorber) having an absorption ability in a wavelength range of 350 nm to 400 nm. Due to the presence of these compounds, it is possible to suppress deterioration of the resin composition due to light in the wavelength range of 350 nm to 400 nm. When a compound having an absorption ability in the wavelength range of 350 nm to 400 nm is used in combination, examples of the compound having an absorption ability in the wavelength range of 350 nm to 400 nm include TINUVIN (registered trademark) series manufactured by BASF, Sankyo Chemical Co., Ltd. Zithriser (registered trademark) series, Adeka's Adekastab (registered trademark) series, Sumitomo Chemical's Sumisorb (registered trademark) series, Kyodo Yakuhin Biosorb (registered trademark) series, Sipro Kasei's Seasorb (registered) Trademark) series or the like can be used.

  The resin composition may contain a surface conditioner, thereby suppressing appearance defects such as striations and dents in the resin layer when the resin composition is cured to form a resin layer. can do. The kind of surface conditioning agent is not specifically limited, A siloxane type surfactant, an acetylene glycol type surfactant, a fluorine type surfactant, an acrylic leveling agent, etc. can be used. As the surface conditioner, for example, BYK (registered trademark) series manufactured by Big Chemie, KF series manufactured by Shin-Etsu Chemical Co., Ltd., or the like can be used.

  The resin composition may contain a dispersant, which stabilizes the dispersibility and suppresses reaggregation of the squarylium compound even if a part of the squarylium compound in the resin composition exists in a dispersed state. can do. The type of the dispersant is not particularly limited. The EFKA series manufactured by Fuka Additives, the BYK (registered trademark) series manufactured by Big Chemie, the Solsperse (registered trademark) series manufactured by Lubrizol Japan, and the Disparon manufactured by Enomoto Kasei Co., Ltd. (Registered trademark) series, Ajinomoto Fine Techno Co., Ltd. Ajisper (registered trademark) series, Shin-Etsu Chemical Co., Ltd. KP series, Kyoeisha Chemical Co., Ltd. polyflow series, DIC Co., Ltd. Megafak (registered trademark) series, Sannopco's Dispar Aid series and the like can be used.

  The resin composition may contain a silane coupling agent or a hydrolyzate or hydrolysis condensate thereof. When the resin composition is cured on the substrate, the cured resin layer is applied to the substrate. Adhesion can be increased.

  The resin composition may contain various additives such as a plasticizer, a surfactant, a viscosity modifier, an antifoaming agent, a preservative, and a specific resistance modifier as necessary.

  The resin composition can be cured by curing. Since the resin composition of this invention contains the squarylium compound represented by the said Formula (1), it can exhibit the original spectral characteristic of a squarylium compound also in hardened | cured material. Therefore, it can be suitably applied to an optical filter or the like that can selectively absorb light in the red to near infrared region and transmit light in the visible light region with high transmittance.

  The cured product may be, for example, a molded product obtained by curing the resin composition in a predetermined shape. The shape of the molded product is not particularly limited, but plate shape, sheet shape, granular shape, powder shape, lump shape, particle aggregate shape, spherical shape, elliptical spherical shape, lens shape, cubic shape, column shape, rod shape, cone shape, Examples include a cylindrical shape, a needle shape, a fiber shape, a hollow fiber shape, and a porous shape.

  The cured product may be one obtained by applying a cured resin composition and curing it. In this case, a liquid or paste-like resin composition is applied on a substrate (for example, a resin plate, a film, a glass plate, etc.) and cured to form a film having a thickness of 200 μm or less or a thickness of more than 200 μm. A sheet-like cured product can be obtained. For the coating of the resin composition, a known method such as a spin coating method, a solvent casting method, a roll coating method, a spray coating method, a bar coating method, a dip coating method, a screen printing method, a flexographic printing method, or an inkjet method is adopted. be able to. The obtained cured product may be peeled off from the substrate and handled as a film or sheet, or may be handled integrally with the substrate.

  The cured product 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 a plurality of resin layers. When the cured product is handled integrally with the substrate, the cured product may be formed only on one side of the substrate or on both sides. In addition, what integrated hardened | cured material and a base material can be formed also by carrying out the thermocompression bonding and the chemical bond of the molded object formed from the resin composition with the base material.

  The cured product obtained from the resin composition of the present invention preferably has a maximum absorption peak in the wavelength range of 650 nm to 950 nm in the absorption spectrum in the wavelength range of 450 nm to 1100 nm. That is, when the absorption spectrum of the cured product is measured, it is preferable to have a peak having an absorption maximum in the wavelength range of 650 nm to 950 nm, and the absorption maximum of the absorption peak to take a maximum value in the wavelength range of 450 nm to 1100 nm. If the cured product of the resin composition exhibits such an absorption spectrum, light in the red to near infrared region can be effectively absorbed. The maximum wavelength is more preferably 670 nm or more, further preferably 685 nm or more, more preferably 900 nm or less, further preferably 850 nm or less, and still more preferably 800 nm or less.

  The resin composition of the present invention can be preferably used as a resin composition for forming a filter used in various applications such as an optical device application, a display device application, a machine part, and an electric / electronic part. The resin composition and its cured product are applied to optical filters such as near-infrared cut filters, or use near-infrared absorbing films and near-infrared absorbing plates that cut off heat rays for energy saving, visible light and near-infrared light. The present invention can also be applied to solar cell materials, plasma display panels (PDPs), specific wavelength absorption filters for CCDs, and the like. Such a filter may be formed from a single or a plurality of resin layers, or may be formed integrally with a support.

  The filter integrated with the support, for example, the resin composition, the surface of the support (or the surface of the other layer in the case of having another layer such as a binder layer between the support and the resin layer). ) By a spin coat method or a solvent cast method and cured. Moreover, you may form a filter by thermocompression-bonding the planar molded body formed from the resin composition with respect to the support body.

  The resin layer formed from the resin composition may be provided only on one side of the support, or may be provided on both sides. The thickness of the resin layer is not particularly limited, but is preferably, for example, 0.5 μm or more, more preferably 1 μm or more, further preferably 2 μm or more, and preferably 1 mm or less, and 500 μm from the viewpoint of securing desired near infrared ray cutting performance. The following is more preferable, and 200 μm or less is more preferable. When the resin layer is formed by applying a resin composition that has been made into a coating on the support, the strength of the filter can be secured by the support, so the thickness of the resin layer should be further reduced. Can do. 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, further preferably 10 μm or less, and particularly preferably 5 μm or less.

  As the support, a transparent substrate such as a resin plate, a resin film, or a glass plate is preferably used. Among these, from the viewpoint of increasing the heat resistance of the optical filter, it is preferable to use a glass substrate as the support, and the optical filter formed in this way can be mounted on an electronic component by, for example, solder reflow. Further, since the glass substrate is not easily cracked or warped even when exposed to a high temperature, it is easy to ensure adhesion with the resin layer. Moreover, you may provide the binder layer formed, for example from the silane coupling agent between a support body and the resin layer, and can improve the adhesiveness of a resin layer and a glass substrate by this. In addition, even if it includes a silane coupling agent, its hydrolyzate, or a hydrolysis condensate in the resin composition which forms a resin layer, the adhesiveness of a resin layer and a glass substrate can be improved.

  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 securing strength, and preferably 0.4 mm or less, and 0.3 mm from the viewpoint of thinning. The following is more preferable.

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

  In the case of forming an optical filter from the resin composition of the present invention, the optical filter is a layer having antireflection and antiglare properties (antireflection film) for reducing the reflection of a fluorescent lamp or the like, and a layer having scratch resistance. In addition, a transparent substrate having other functions may be included.

  The optical filter may have a near-infrared reflective film (for example, a reflective film having a wavelength range of 700 nm to 800 nm) on the resin layer. It is preferable that the near-infrared reflective film is provided on the light incident side with respect to the resin layer. If the optical filter is provided with a near-infrared reflective film, the near-infrared light can be further cut from the transmitted light of the optical filter. Note that the near-infrared reflective film may have an ultraviolet reflection function.

  The near-infrared reflective film or antireflection film (visible light antireflection film) can be composed of a dielectric multilayer film in which high refractive index material layers and low refractive index material layers are alternately laminated. Therefore, when providing such a function to an optical filter, the optical filter preferably has a dielectric multilayer film. As a material constituting the high refractive index material layer, a material having a refractive index of 1.7 or more can be used, and a material having a refractive index range of 1.7 to 2.5 is usually selected. Examples of the material constituting 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; silicon nitride Nitrides such as oxides, mixtures of the nitrides, and those doped with metals such as aluminum and copper and carbon (for example, tin-doped indium oxide (ITO), antimony-doped tin oxide (ATO)), etc. It is done. As a material constituting the low refractive index material layer, a material having a refractive index of 1.6 or less can be used, and a material having a refractive index range of 1.2 to 1.6 is usually selected. Examples of the material constituting the low refractive index material layer include silicon dioxide (silica), alumina, lanthanum fluoride, magnesium fluoride, and aluminum hexafluoride sodium.

  The optical filter may also include an aluminum vapor deposition film, a noble metal thin film, a resin film in which metal oxide fine particles containing indium oxide as a main component and containing a small amount of tin oxide are dispersed.

  The thickness of the optical filter is preferably 1 mm or less, for example. Thereby, for example, it is possible to sufficiently meet the demand for downsizing of the image sensor. The thickness of the optical filter is more preferably 500 μm or less, further preferably 300 μm or less, still more preferably 150 μm or less, and preferably 30 μm or more, more preferably 50 μm or more.

  The optical filter can be used as one of constituent members of sensors such as an image sensor (imaging device), an illuminance sensor, and a proximity sensor. For example, an image sensor is used as an electronic component that converts light of a subject into an electrical signal and outputs the signal, and includes a charge coupled device (CCD), a complementary metal-oxide semiconductor (CMOS), and the like. The image sensor can be used for a mobile phone camera, a digital camera, an in-vehicle camera, a surveillance camera, a display element (LED or the like), 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.) or a lens as necessary.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples, and is implemented with appropriate modifications within a range that can meet the purpose described above and below. Any of these may be included in the technical scope of the present invention.

(1) Synthesis of compound (1-1) Synthesis example 1: Synthesis of squarylium compound A In a 300 mL four-necked flask, 5 g of dimethylformamide, 2.2 g of potassium carbonate, 1.07 g of 1,2,3,4-tetrahydroquinoline (0.008 mol) and 1.4 g of 2-iodopropane were added, and the mixture was reacted for 4 hours under conditions of 80 ° C. with stirring using a stirring blade under nitrogen flow (10 mL / min). After completion of the reaction, the obtained reaction solution was added to a beaker containing 50 mL of an aqueous potassium hydroxide solution and 50 mL of ethyl acetate while stirring. The aqueous solution was alkaline. After stirring for a while, the organic phase was extracted with a separatory funnel, and magnesium sulfate (anhydrous) was added to the extracted organic phase for dehydration. After the solid matter (inorganic content) was filtered off from the organic phase, the solvent was distilled off using an evaporator. After evaporation, 0.9 g of intermediate A1 was obtained by appropriately using silica gel column chromatography (developing solvent: chloroform) and concentrating and vacuum drying. The yield based on 1,2,3,4-tetrahydroquinoline was 64.2 mol%.

  Next, 2.80 g (0.0160 mol) of intermediate A1 and 46 g of sulfuric acid were placed in a 50 mL two-necked flask under nitrogen flow (10 mL / min), and the temperature in the flask was 0 while stirring using a stirring blade. Ice-cooled to ˜5 ° C. Thereto, 8.2 g of mixed acid composed of 1.6 g of nitric acid and 6.6 g of sulfuric acid was gently added dropwise so that the temperature in the flask could be maintained at 0 to 5 ° C., and stirring was continued for 1 hour after completion of the addition. After the stirring was completed, the obtained reaction solution was poured into 200 g of ice water, and neutralized by adding 60 g of potassium hydroxide little by little. After addition of potassium hydroxide, the aqueous solution was alkaline. After adding 200 g of ethyl acetate and stirring for a while, the organic phase was extracted with a separatory funnel, and magnesium sulfate (anhydrous) was added to the extracted organic phase for dehydration. After the solid matter (inorganic content) was filtered off from the organic phase, the solvent was distilled off using an evaporator. After distillation, 3.1 g of intermediate A2 was obtained by appropriately using silica gel column chromatography (developing solvent: chloroform) and concentrating and vacuum drying. The yield based on the intermediate A1 was 88.0 mol%.

  Next, 2.64 g (0.012 mol) of intermediate A2 and 9.0 g of concentrated hydrochloric acid (hydrochloric acid concentration 36% by weight) were placed in a 100 mL two-necked flask, and a magnetic stirrer was placed under a nitrogen flow (5 mL / min). While stirring, a solution containing 9.1 g of tin chloride dihydrate and 9.1 g of concentrated hydrochloric acid (hydrochloric acid concentration 36% by weight) was added little by little while paying attention to the heat of reaction. After the addition, the mixture was stirred at room temperature for about 3 hours. Thereafter, the obtained reaction solution was added to a beaker containing 100 g of pure water and 100 g of ethyl acetate while stirring. Potassium hydroxide solution was added little by little, and after stirring for a while when the pH of the aqueous solution reached about 10, the organic phase was extracted with a separatory funnel, and magnesium sulfate (anhydrous) was added to the extracted organic phase. And dehydrated. After filtering off solids (inorganic content) from this organic phase, the solvent was concentrated using an evaporator, then appropriately using silica gel column chromatography (developing solvent: chloroform), and concentrating and vacuum drying to obtain an intermediate. 0.96 g of body A3 was obtained. The yield based on the intermediate A2 was 42.0 mol%.

  Next, 2.72 g (0.0143 mol) of intermediate A3 and 50 g of ultra-dehydrated chloroform were placed in a 100 mL three-necked flask, and triethylamine was stirred with a magnetic stirrer under nitrogen flow (5 mL / min). 4.34 g (0.0429 mol) and 5.45 g (0.0286 mol) of n-decanoyl chloride were added and reacted at room temperature for 12 hours. After completion of the reaction, the resulting reaction solution was added to ion exchange water and extracted with ethyl acetate. Magnesium sulfate (anhydrous) was added to the extracted organic phase for dehydration. After filtering off solids (inorganic content) from this organic phase, the solvent was concentrated using an evaporator, then appropriately using silica gel column chromatography (developing solvent: chloroform), and concentrating and vacuum drying to obtain an intermediate. 3.10 g of body A4 was obtained. The yield based on the intermediate A3 was 62.9 mol%.

  Next, 4.93 g (0.0143 mol) of intermediate A4, 0.82 g (0.0072 mmol) of squaric acid, 30 g of 1-butanol and 30 g of toluene were placed in a 300 mL two-necked flask under nitrogen flow (10 mL / min). ), The mixture was stirred using a magnetic stirrer, and the reaction was carried out for 3 hours under reflux conditions while removing the eluted water using a Dean Stark apparatus. After completion of the reaction, the mixture was cooled to room temperature, and the precipitate was filtered off. The precipitate separated by filtration was washed with methanol, only the precipitate was filtered again, and the obtained cake (solid) was purified by column chromatography using alumina (developing solvent: chloroform). The obtained purified product was dried at 60 ° C. for 12 hours using a vacuum dryer to obtain 3.9 g of the target product, squarylium compound A. The yield based on squaric acid was 71.1 mol%.

(1-2) Synthesis Example 2: Synthesis of squarylium compound B According to the same procedure as in Synthesis Example 1, except that n-decanoyl chloride was changed to palmitoyl chloride (n-hexadecanoyl chloride) in Synthesis Example 1. The squarylium compound B shown in Table 1 was obtained. The yield based on squaric acid was 86.1 mol%.

(1-3) Synthesis Example 3: Synthesis of squarylium compound C In a 300 mL four-necked flask, 110 g of chloroform, 1.8 g of acetic acid, 5.4 g of 7-nitro-1,2,3,4-tetrahydroquinoline (0.0303 mol) ), 12.84 g (0.0606 mol) of sodium triacetoxyborohydride was added, and 4.37 g (0.0606 mol) of isobutyraldehyde was added over 10 minutes while stirring with a stirring blade under nitrogen flow (10 mL / min). It was dripped. After completion of the dropwise addition, the resulting reaction solution was added to 300 g of water and neutralized with hydrochloric acid. Thereto, 300 g of ethyl acetate was added, the organic phase was extracted with a separatory funnel, and magnesium sulfate (anhydrous) was added to the extracted organic phase for dehydration. After filtering off solids (inorganic content) from this organic phase, the solvent was concentrated using an evaporator, then appropriately using silica gel column chromatography (developing solvent: chloroform), and concentrating and vacuum drying to obtain an intermediate. 6.13 g of body C1 was obtained. The yield based on 7-nitro-1,2,3,4-tetrahydroquinoline was 86.4 mol%. Next, intermediate C2 was synthesized from intermediate C1 according to the synthesis procedure from intermediate A2 of synthesis example 1 to intermediate A3 (however, intermediate A2 was changed to intermediate C1). The yield of the intermediate C2 with respect to the intermediate C1 was 83.0 mol%. Further, intermediate C3 was synthesized from intermediate C2 according to the synthesis procedure from intermediate A3 of synthesis example 1 to intermediate A4 (however, intermediate A3 was changed to intermediate C2). The yield of intermediate C3 with respect to intermediate C2 was 92.0 mol%. Subsequently, from the intermediate C3, the squarylium compound C was synthesized according to the synthesis procedure of the squarylium compound A from the intermediate A4 of Synthesis Example 1 (however, the intermediate A4 is changed to the intermediate C3). The yield of squarylium compound C with respect to squaric acid was 63.5 mol%.

(1-4) Synthesis Example 4: Synthesis of squarylium compound D According to the same procedure as in Synthesis Example 3, except that n-decanoyl chloride was changed to palmitoyl chloride (n-hexadecanoyl chloride) in Synthesis Example 3. The squarylium compound D shown in Table 1 was obtained. The yield based on squaric acid was 77.4 mol%.

(1-5) Synthesis Example 5: Synthesis of comparative squarylium compound A Comparative synthetic squarylium compound A shown in Table 1 was obtained by the same procedure as in Synthesis example 4 except that isobutyraldehyde was changed to propionaldehyde in synthesis example 4. It was. The yield based on squaric acid was 69.9 mol%.

(2) Preparation of resin composition (2-1) Preparation of curing catalyst In accordance with the synthesis method described in International Publication No. 1997/031924, Ando Parachemy Co., Ltd. having a TPB (tris (pentafluorophenyl) borane) content of 7% 255 g of Isopar (registered trademark) E solution produced was prepared. Water was added dropwise to this solution at 60 ° C. to precipitate white crystals, which were cooled to room temperature, filtered with suction, and washed with n-heptane. The obtained cake was dried at 60 ° C. under reduced pressure to obtain 18.7 g of TPB / water complex (TPB-containing powder) as white crystals. This complex had a water content of 9.2% (Karl Fischer moisture meter) and a TPB content of 90.8%. ¹⁹ F-NMR analysis and GC analysis were performed on the dried complex, but no peaks other than TPB were detected. 2.0 g of the obtained TPB / water complex and 1.1 g of toluene were blended and mixed at room temperature for 10 minutes. Thereafter, 2.6 g of a 2 mol / L ammonia / ethanol solution was added and mixed for 60 minutes at room temperature to obtain a uniform solution of TPB catalyst. This was used as a cationic curing catalyst.

(2-2) Preparation of Silane Hydrolyzate Solution 3-Glycidoxypropyltrimethoxysilane (manufactured by Dow Corning Toray, ofs-6040) 24.7 parts by mass, 32.1 parts by mass of 2-propanol, and distilled water It mixed with 3.4 mass parts, and mixed uniformly at 25 degreeC. Thereto, 1.54 parts by mass of formic acid was added and mixed for 90 minutes, and the hydrolysis reaction of 3-glycidoxypropyltrimethoxysilane was advanced to obtain a silane hydrolyzate solution.

(2-3) Preparation of epoxy resin composition 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol as an epoxy resin (manufactured by Daicel, EHPE3150) ) 100 parts by mass, toluene 150 parts by mass and o-xylene 75 parts by mass, 8.9 parts by mass of any of squarylium compounds A to D obtained in the above synthesis examples or comparative squarylium compound A, and surface adjustment As an agent, BYK-306 (polyether-modified polydimethylsiloxane) manufactured by BYK-Chemie Co., Ltd. was blended in an amount of 0.3 part by mass and mixed uniformly at 40 ° C. After the temperature of the obtained mixture was lowered to 25 ° C., 2.5 parts by mass of the cationic curing catalyst obtained above and 10 parts by mass of the silane hydrolyzate solution were added and mixed uniformly, and this was mixed with a filter having a pore size of 0.45 μm ( The product was filtered through GL Sciences Co., Ltd. (Chromatodisc non-aqueous 13N) to remove foreign matters, and an epoxy resin composition was obtained.

(3) Production of optical filter Each resin composition obtained above was dropped on a glass substrate (Schott, D263Teco) by 2 cc, and then spin coater (Mikasa, 1H-D7) was used. The resin composition was formed on a glass substrate at 1600 rotations over 2 seconds, held at that number of rotations for 20 seconds, and then 0 rotations over 0.2 seconds. The glass substrate on which the resin composition was formed was initially dried at 100 ° C. for 3 minutes using a precision thermostat (manufactured by Yamato Scientific Co., Ltd., DH611). Then, after nitrogen substitution at 50 ° C. for 30 minutes using an inert oven (manufactured by Yamato Kagaku Co., Ltd., DN610I), the temperature was raised to 190 ° C. in about 15 minutes and dried at 190 ° C. for 30 minutes in a nitrogen atmosphere. A resin layer (absorbing layer) was formed on the glass substrate. The thickness of the resin layer formed on the glass substrate was 2 μm. The thickness of the resin layer was determined from the difference between the thickness of the glass substrate on which the resin layer was formed and the thickness of the glass substrate alone with a micrometer.

(4) Transmission spectrum measurement of optical filter About each optical filter which formed the resin layer on the glass substrate, a transmission spectrum was measured at a measurement pitch of 1 nm using a spectrophotometer (manufactured by Shimadzu Corporation, UV-1800). The light transmittance at 300 nm to 1100 nm was determined. The transmission spectrum of the optical filter formed from the resin composition containing the squarylium compound B is shown in FIG. 1, and the transmission spectrum of the optical filter formed from the resin composition containing the comparative squarylium compound A is shown in FIG.

  In the squarylium compounds A to D, a branched alkyl group is bonded to the nitrogen atom of the nitrogen-containing heterocyclic ring of the ring A and the ring B of the above formula (1). When the optical filter formed from the resin composition containing any of the squarylium compounds A to D measured the transmission spectrum, it showed an absorption peak having an absorption maximum in the vicinity of a wavelength of 700 nm, and had a wavelength of 450 nm to 600 nm in the visible light region. There was virtually no absorption peak in the range. The resin composition containing the squarylium compounds A to D was able to exhibit the original spectral characteristics of the squarylium compounds A to D in the cured product.

  On the other hand, the comparative squarylium compound A is a compound in which a linear alkyl group is bonded to the nitrogen atom of the nitrogen-containing heterocyclic ring of the ring A and the ring B of the above formula (1). The optical filter formed from the resin composition containing the comparative squarylium compound A was measured for a transmission spectrum. As a result, a relatively large absorption peak having an absorption maximum near a wavelength of 560 nm in addition to an absorption peak having an absorption maximum near a wavelength of 700 nm. showed that. The comparative squarylium compound A showed an absorption peak having an absorption maximum in the vicinity of a wavelength of 700 nm and did not show an absorption peak having an absorption maximum in the vicinity of a wavelength of 560 nm in the solution. The comparative squarylium compound A did not show the original spectral characteristics of the comparative squarylium compound A as shown in the solution in the resin cured product.

  The resin composition of the present invention can be used for, for example, an optical filter used for a mobile phone camera, a digital camera, an in-vehicle camera, a surveillance camera, a display element (LED or the like), and the like.

Claims (7)

A resin composition comprising a squarylium compound represented by the following formula (1) and a thermosetting resin.

[In Formula (1),
R ^{1 to} R ³ and R ^{5 to} R ⁷ each independently represents a hydrogen atom, an organic group or a polar functional group,
Ring A and ring B each independently represent a nitrogen-containing heterocyclic ring, and a branched alkyl group which may have a substituent is bonded to the nitrogen atom of the heterocyclic ring. ] The resin composition according to claim 1, wherein the squarylium compound is represented by the following formula (2).

[In Formula (2),
R ^{1 to} R ³ and R ^{5 to} R ⁷ have the same meaning as above,
R ⁴ and R ⁸ represent a branched alkyl group which may have a substituent. ] The resin composition according to claim 1 or 2, wherein R ¹ or R ² represents a group represented by the following formula (3), and R ⁵ or R ⁶ represents a group represented by the following formula (4). .
—NH—C (═O) —R ⁹ (3)
—NH—C (═O) —R ¹⁰ (4)
[In Formula (3) and Formula (4), R ⁹ and R ¹⁰ each independently represents an alkyl group having 5 or more carbon atoms which may have a substituent. ]   The resin composition according to any one of claims 1 to 3, wherein the thermosetting resin is an epoxy resin.   Hardened | cured material which hardened | cured the resin composition as described in any one of Claims 1-4.   An optical filter comprising the resin composition according to any one of claims 1 to 4 or the cured product according to claim 5.   A sensor comprising the optical filter according to claim 6.

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