Resin composition, coated and dried product, melt-kneaded product, optical filter, image display device, solid-state imaging device, squarylium compound and method for producing the same

Abstract

Provided are: a resin composition comprising one or more squarylium compounds and a resin, wherein the squarylium compounds include at least one squarylium compound selected from among ones represented by a specific formula; a dried coating or a melt-kneaded mixture; an optical filter including either of these; an image display device and a solid imaging element which include this optical filter; squarylium compounds represented by the specific formula; and a method for producing the squarylium compounds.

Description

[Technical Field]

[0001] The present invention relates to a resin composition suitable as a constituent material for optical filters, a coated and dried product or a melt-kneaded product thereof, an optical filter using the composition, and an image display device and a solid-state imaging device using the optical filter. The present invention also relates to a squarylium compound suitable as a light-absorbing component of the resin composition, and a method for producing the same. [Background technology]

[0002] Because squarylium compounds can absorb light having a specific wavelength, they are promising compounds for use as optical materials such as organic dyes, etc. For example, their application to optical applications such as charge generation materials for electrophotographic photoreceptors (e.g., Patent Document 1), dyes (e.g., dyes for electrophotographic toners (Patent Document 2)), and light absorbers for optical filters attached to image display devices and the like (e.g., Patent Document 3) has been proposed.

[0003] Among image display devices, liquid crystal display devices are finding increasing applications due to their low power consumption and space-saving features. In these liquid crystal display devices, the liquid crystal panel that displays images is a non-emissive element that does not emit light, so a backlight unit is disposed behind the liquid crystal panel. This backlight unit uses a white LED as its light source, which produces white light by mixing blue light emitted from a blue light-emitting diode (LED) with light emitted from a yellow phosphor or green and red phosphors. For backlight units using such white LEDs, technologies have been proposed that block (absorb) light of unnecessary wavelengths emitted from the white LED to improve the color reproduction range. Various optical filters (light-absorbing films) that block (absorb) light of unnecessary wavelengths have been proposed, including those containing a dye such as a squarylium compound and a resin. Squarylium compounds are fluorescent dyes with high fluorescence quantum yields, but they are easily oxidized (decomposed) by light (irradiation), impairing their dye function. Therefore, it has been considered difficult to apply them to applications requiring high light resistance, i.e., image display devices, inkjet dyes, etc., that maintain the ability to block specific wavelengths of light (light absorption ability) even when irradiated with light. As an optical filter for improving such a decrease in light resistance, for example, Patent Document 3 proposes an optical filter made of a resin composition containing a compound represented by a specific general formula having a specific squarylium compound structural portion and a metallocene structural portion, and a resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 169453 / 1983 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-036811 [Patent Document 3] International Publication No. 2019 / 167930A1 Summary of the Invention [Problem to be solved by the invention]

[0005] When a film is formed using a resin solution in which a typical squarylium compound and resin are dissolved in an organic solvent, the film formation state and the state of the squarylium compound are likely to be uneven, which can impair the light absorption ability of the optical filter.

[0006] An object of the present invention is to provide an optical filter that can highly absorb (block passage of) light of a specific target wavelength, such as light of an unwanted wavelength among incident light, and that also has excellent light resistance. Another object of the present invention is to provide a resin composition, a coated and dried product, or a melt-kneaded product that is suitable as a material for forming the optical filter, etc., as well as a squarylium compound that is suitable as a light-absorbing component of the resin composition, coated and dried product, or melt-kneaded product, and a method for producing the same. A further object of the present invention is to provide an image display device and a solid-state imaging device that include the optical filter. [Means for solving the problem]

[0007] In view of the above-mentioned problems, the present inventors have conducted extensive research and found that squarylium compounds having a specific chemical structure represented by formula (1) or (3) exhibit sufficient solubility in organic solvents used in the film formation of optical filters, while suppressing association due to the high planarity of the squarylium compound, despite having a betaine structure in the molecule. Further research based on this finding has revealed that when a resin composition containing the squarylium compound in combination with a resin is dissolved in an organic solvent to form a film, a coated and dried product (e.g., a film) can be formed with reduced variation in the film formation state and the state of the squarylium compound present, and the obtained film (optical filter) can selectively and effectively absorb light of a specific wavelength, and maintains a high level of light absorption ability even when irradiated with light, thereby exhibiting excellent light resistance. Furthermore, the inventors have found that a melt-kneaded product obtained by melt-kneading a squarylium compound with a resin can also selectively and effectively absorb light of a specific wavelength, similar to the coated and dried product, and exhibits excellent light resistance. The present invention has been completed as a result of further investigations based on these findings.

[0008] That is, the above problem is solved by the following means. <1> A resin composition containing a squarylium compound and a resin, A resin composition, wherein the squarylium compound comprises at least one selected from squarylium compounds represented by the following formula (1) and squarylium compounds represented by the following formula (3): [ka] In formula (1), R 1 ~R 4 represents an alkyl group or an aryl group which may have a substituent, provided that R 1 ~R 4 at least one of R is an aryl group; 1 ~R 4 At least one of R is an alkyl group. 5 and R 6 Ha-NR 9 R 10 indicates R 9 and R 10 is a hydrogen atom, -COR N , -COOR N , -CON(R N )2 or -SO2R N indicates R N represents a hydrogen atom or an alkyl or aryl group which may have a substituent. 7 and R 8 represents a substituent, and m and n are integers of 0 to 3. However, the squarylium compound represented by formula (1) has at least one branched alkyl group having 4 or more carbon atoms. [ka] In formula (3), Dye represents a structural portion obtained by removing n1 hydrogen atoms from a squarylium compound represented by formula (4) below, and Q 1 represents a group represented by the following formula (4M), wherein n1 is an integer of 1 to 6. [ka] In formula (4), R 1 ~R 4 represents an alkyl group or an aryl group which may have a substituent, provided that R 1 ~R 4at least one of R is an aryl group; 1 ~R 4 At least one of R is an alkyl group. 5 and R 6 Ha-NR 9 R 10 indicates R 9 and R 10 is a hydrogen atom, -COR N , -COOR N , -CON(R N )2 or -SO2R N indicates R N represents a hydrogen atom or an alkyl or aryl group which may have a substituent. 7 and R 8 represents a substituent, and m and n are integers of 0 to 3. [ka] In formula (4M), L represents a single bond or a divalent linking group that is not conjugated with the dye. 1m ~R 9m represents a hydrogen atom or a substituent. M represents Fe, Co, Ni, Ti, Cu, Zn, Zr, Cr, Mo, Os, Mn, Ru, Sn, Pd, Rh, V, or Pt. * represents the bond to the dye. <2> The squarylium compound represented by formula (1) is represented by the following formula (2): <1> The resin composition according to claim 1. [ka] In formula (2), R 2 and R 4 represents an alkyl group. 11 and R 12 represents a substituent, and p and q are integers of 0 to 5. 5 ~R 8 , m and n are R in formula (1) 5 ~R 8 , m and n. However, the squarylium compound represented by formula (2) has at least one branched alkyl group having 4 or more carbon atoms. <3> R 2 , R 4 , R 9 and R10 At least one of the above contains a branched alkyl group having 4 or more carbon atoms. <1> or <2> The resin composition according to claim 1.

[0009] <4> The squarylium compound represented by formula (4) is represented by the following formula (5): <1> The resin composition according to claim 1. [ka] In formula (5), R 2 and R 4 represents an alkyl group. 11 and R 12 represents a substituent, and p and q are integers of 0 to 5. 5 ~R 8 , m and n are R in formula (4) 5 ~R 8 , m and n. <5> The squarylium compound represented by formula (4) or the squarylium compound represented by formula (5) has at least one branched alkyl group having 4 or more carbon atoms. <1> or <4> The resin composition according to claim 1. <6> M in formula (4M) is Fe; <1> , <4> or <5> The resin composition according to claim 1. <7> The glass transition temperature of the resin is -80 to 200°C. <1> ~ <6> The resin composition according to any one of the above. <8> The resin is at least one selected from polystyrene resin, cellulose acylate resin, poly(meth)acrylic resin, polyester resin, cycloolefin resin, and polycarbonate resin. <1> ~ <7> The resin composition according to any one of the above. <9> The composition contains a solvent having a boiling point of 200°C or less, and a resin and a squarylium compound are dissolved in the solvent. <1> ~ <7> The resin composition according to any one of the above. <10> the above <9> 2. A dried coated product obtained by coating the resin composition according to claim 1 on a substrate and drying it. <11> the above <1> ~ <8> A melt-kneaded product of the resin composition according to any one of the above.

[0010] <12> the above <1> ~ <7> The resin composition according to any one of the above items. <10> or the coated and dried product according to <11> An optical filter comprising the melt-kneaded product according to claim 1. <13> It is in the form of a membrane or film, <12> The optical filter according to claim 1. <14> the above <12> or <13> An image display device comprising the optical filter according to claim 1. <15> the above <12> or <13> A solid-state imaging device comprising the optical filter according to claim 1.

[0011] <16> A squarylium compound represented by the following formula (1) or (3): [ka] In formula (1), R 1 ~R 4 represents an alkyl group or an aryl group which may have a substituent, provided that R 1 ~R 4 at least one of R is an aryl group; 1 ~R 4 At least one of R is an alkyl group. 5 and R 6 Ha-NR 9 R 10 indicates R 9 and R 10 is a hydrogen atom, -COR N , -COOR N , -CON(R N )2 or -SO2R N indicates R N represents a hydrogen atom or an alkyl or aryl group which may have a substituent. 7 and R 8 represents a substituent, and m and n are integers of 0 to 3. However, the squarylium compound represented by formula (1) has at least one branched alkyl group having 4 or more carbon atoms. [ka] In formula (3), Dye represents a structural portion obtained by removing n1 hydrogen atoms from a squarylium compound represented by formula (4) below, and Q 1represents a group represented by the following formula (4M), wherein n1 is an integer of 1 to 6. [ka] In formula (4), R 1 ~R 4 represents an alkyl group or an aryl group which may have a substituent, provided that R 1 ~R 4 at least one of R is an aryl group; 1 ~R 4 At least one of R is an alkyl group. 5 and R 6 Ha-NR 9 R 10 indicates R 9 and R 10 is a hydrogen atom, -COR N , -COOR N , -CON(R N )2 or -SO2R N indicates R N represents a hydrogen atom or an alkyl or aryl group which may have a substituent. 7 and R 8 represents a substituent, and m and n are integers of 0 to 3. [ka] In formula (4M), L represents a single bond or a divalent linking group that is not conjugated with the dye. 1m ~R 9m represents a hydrogen atom or a substituent. M represents Fe, Co, Ni, Ti, Cu, Zn, Zr, Cr, Mo, Os, Mn, Ru, Sn, Pd, Rh, V, or Pt. * represents the bond to the dye. <17> The squarylium compound represented by formula (1) is represented by the following formula (2): <16> The squarylium compound according to claim 1. [ka] In formula (2), R 2 and R 4 represents an alkyl group. 11 and R 12 represents a substituent, and p and q are integers of 0 to 5.5 ~R 8 , m and n are R in formula (1) 5 ~R 8 , m and n. However, the squarylium compound represented by formula (2) has at least one branched alkyl group having 4 or more carbon atoms. <18> The squarylium compound represented by formula (4) is represented by the following formula (5): <16> The squarylium compound according to claim 1. [ka] In formula (5), R 2 and R 4 represents an alkyl group. 11 and R 12 represents a substituent, and p and q are integers of 0 to 5. 5 ~R 8 , m and n are R in formula (4) 5 ~R 8 , m and n. <19> A method for producing a squarylium compound, comprising reacting a compound represented by the following formula (A) with squaric acid or a compound represented by the following formula (B) to produce a squarylium compound represented by the following formula (1): [ka] In formula (A), formula (B) and formula (1), R 1 ~R 4 represents an alkyl group or an aryl group which may have a substituent. 5 and R 6 Ha-NR 9 R 10 indicates R 9 and R 10 is a hydrogen atom, -COR N , -COOR N , -CON(R N )2 or -SO2R N indicates R N represents a hydrogen atom or an alkyl or aryl group which may have a substituent. 7 and R 8 represents a substituent, and m and n are integers of 0 to 3. However, in the compound represented by formula (A) to be reacted with squaric acid, R 1 and R 2 at least one of R is an aryl group; 1 and R 2 At least one of them is an alkyl group, and has at least one branched alkyl group having 4 or more carbon atoms. In the compounds of formula (A) or formula (B) that are reacted with each other, R 1 ~R 4 at least one of R is an aryl group; 1 ~R 4 At least one of them is an alkyl group, and has at least one branched alkyl group having 4 or more carbon atoms. The squarylium compound represented by formula (1) has at least one branched alkyl group having 4 or more carbon atoms. [Effects of the Invention]

[0012] The present invention can provide an optical filter that can highly absorb (block passage of) light of a specific target wavelength, such as light of an unwanted wavelength, among incident light, and that also has excellent light resistance. The present invention can also provide a resin composition, a coated and dried product, or a melt-kneaded product suitable as a material for forming the optical filter, etc., as well as a squarylium compound suitable as a light-absorbing component thereof and a method for producing the same. Furthermore, the present invention can provide an image display device and a solid-state imaging device equipped with the optical filter. The above and other features and advantages of the present invention will become more apparent from the following description, taken in conjunction with the accompanying drawings where appropriate. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram illustrating an outline of an embodiment of a liquid crystal display device provided with an optical filter of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] In the compounds (dyes) represented by the chemical structural formulas of the present invention and the present specification, the cations are delocalized, and multiple tautomeric structures exist. Therefore, in the present invention, if at least one tautomeric structure of a dye corresponds to a chemical structural formula defined by each general formula, the dye is considered to be a dye represented by each general formula. Therefore, a dye represented by a specific general formula can be said to be a dye whose at least one tautomeric structure can be represented by a specific general formula. In the present invention, the dye represented by a general formula may have any tautomeric structure, as long as at least one of the tautomeric structures corresponds to this general formula.

[0015] In the present invention, a numerical range expressed by "to" means that the numerical values ​​before and after it are included as the upper and lower limits. In the present invention, when multiple numerical ranges are set for the content, physical properties, etc. of a compound, etc., the upper and lower limits forming the numerical range are not limited to a specific combination of upper and lower limits, and any numerical range can be formed by appropriately combining the upper and lower limits of each numerical range.

[0016] In the present invention, when there are multiple substituents, linking groups, etc. (hereinafter referred to as "substituents, etc.") represented by a specific symbol, or when multiple substituents, etc. are specified simultaneously or alternatively, it means that the respective substituents, etc. may be the same or different from each other. This also applies to the specification of the number of substituents, etc. Furthermore, when multiple substituents, etc. are close to each other (particularly adjacent), it means that they may be linked to each other or condensed to form a ring.

[0017] In the present invention, the term "compound" is used to mean not only the compound itself, but also its salts and ions. It also means compounds in which the structure has been partially modified as long as the intended effect is not impaired. Examples of salts of compounds include acid addition salts of compounds formed between a compound and an inorganic or organic acid, and base addition salts of compounds formed between a compound and an inorganic or organic base. Examples of ions of compounds include ions generated when the salts of the above-mentioned compounds are dissolved in water or a solvent.

[0018] In this specification, substituents (similar to linking groups) that are not specified as substituted or unsubstituted mean that the group may have any substituent within the range that does not impair the desired effect. This also applies to compounds or repeating units that are not specified as substituted or unsubstituted.

[0019] In the present invention, when the number of carbon atoms (also referred to as the carbon number) of a certain group is specified, this number of carbon atoms means the number of carbon atoms in the entire group. In other words, when this group has a further substituent, this number means the total number of carbon atoms including this substituent. In this case, when a certain group has a metallocene structural part (group) as a substituent, the number of carbon atoms forming this metallocene structural part is not included in the number of carbon atoms of the certain group.

[0020] In the present invention, when a group can form both an acyclic skeleton and a cyclic skeleton, the group includes both an acyclic skeleton group and a cyclic skeleton group unless otherwise specified. For example, an alkyl group includes a linear alkyl group, a branched alkyl group, and a cyclic (cyclo)alkyl group unless otherwise specified. When a group forms a cyclic skeleton, the lower limit of the number of carbon atoms in the cyclic skeleton group is preferably 3 or more, more preferably 5 or more, regardless of the lower limit of the number of carbon atoms specifically specified for the group.

[0021] In the present invention, the term "(meth)acrylic" is used to mean both methacrylic and acrylic.

[0022] [Resin composition] The resin composition of the present invention contains a squarylium compound represented by the following formula (1) or (3) and a resin as a binder. The squarylium compound and the resin contained in the resin composition of the present invention may each be one type, or two or more types. This squarylium compound has a squarylium structural moiety that absorbs visible light in a specific wavelength region, as represented by formula (1) or (3) described below, and further has a branched alkyl group having 4 or more carbon atoms or a specific metallocene structural moiety. As described below, squarylium compounds having such a structure can provide optical filters with high light absorption ability and excellent light resistance. Moreover, when the squarylium compound having a metallocene structural moiety represented by formula (3) is excited by light absorption, the metallocene structural moiety suppresses decomposition of the squarylium compound, thereby enabling further improvement in light resistance. In a preferred embodiment in which the squarylium compound represented by formula (3) has at least one branched alkyl group having 4 or more carbon atoms, the above properties are further enhanced. In the squarylium compounds represented by formula (1) and formula (3), decomposition of the squarylium compounds can be effectively suppressed by a preferred embodiment in which the squarylium compounds form intramolecular hydrogen bonds. Therefore, the resin composition of the present invention is suitable as a material for forming components that absorb light with wavelengths of 670 to 740 nm, such as the optical filter of the present invention (a filter containing a squarylium compound and a resin), and also as a material for forming a near-infrared cut filter, as described below.

[0023] The resin composition of the present invention may be any composition containing a squarylium compound and a resin, and may take an appropriate form depending on the intended use, the method of manufacturing the optical filter, and the like. Examples of suitable compositions include a (simple) mixture obtained by dry-mixing a squarylium compound and a resin using a standard method; a liquid composition obtained by dissolving a squarylium compound and a resin in a solvent (described below) (obtained by wet-mixing a squarylium compound, a resin, and a solvent using a standard method); a coated and dried product (usually a membrane-like or film-like molded product) obtained by coating and drying this liquid composition; and a molten mixture (also referred to as a melt-solidified product) obtained by melt-mixing a squarylium compound and a resin and then cooling and solidifying the mixture. The coated and dried product may contain residual solvent as long as the effects of the present invention are not impaired. The residual solvent amount can be, for example, 5% by mass or less in the coated and dried product. The coated and dried product and the melt-kneaded product differ from simple mixtures of a squarylium compound and a resin in that the resin forms a (continuous) matrix. That is, the coated and dried product is a product in which the squarylium compound and resin are once dissolved in a solvent and mixed, and then the resin (including the squarylium compound) precipitates (solidifies) while still in this mixed state. On the other hand, the melt-kneaded product is a product in which the squarylium compound and resin are once melted and melt-mixed, and then the resin (including the squarylium compound) is cooled and solidified while still in this molten mixed state. As will be described later, the resin composition of the present invention, particularly the liquid composition, can suppress variations during film formation and photooxidative decomposition of the squarylium compound. Furthermore, the coated and dried product and molten mixture of the present invention suppress variations in the state of the squarylium compound, so that they do not impair light absorption ability, and they also suppress oxidative decomposition due to light irradiation, thereby exhibiting high light resistance. The methods and conditions for coating, drying, and melt-kneading will be described later. The resin composition of the present invention, particularly the coated and dried product and the molten mixture, may be a cured product, but is preferably an uncured product.

[0024] <Squarylium compounds> The squarylium compound contained in the resin composition of the present invention (also referred to as the squarylium compound of the present invention) is a dye compound represented by the following formula (1) or (3). A squarylium compound represented by the following formula (1) (sometimes referred to as compound (1)) has a chemical structure represented by formula (1) and has at least one branched alkyl group having 4 or more carbon atoms introduced therein. On the other hand, a squarylium compound represented by formula (3) (sometimes referred to as compound (3)) is a compound having a specific metallocene structural part introduced into a chemical structure represented by formula (4), and is preferably a compound having at least one branched alkyl group having 4 or more carbon atoms introduced therein. Both Compound (1) and Compound (3) have a sharp absorption spectrum with a maximum absorption wavelength in the wavelength region of 670 to 740 nm, preferably 680 to 720 nm. This wavelength region is near the border between the near-infrared region and the visible region, and is the wavelength region of light that should be absorbed as unwanted light in display applications, sensor applications, and the like. Therefore, optical filters containing the above compounds are preferably used as light-blocking members (optical components) in displays having LED backlights, for example, as optical filters in image display devices. Furthermore, the optical filter of the present invention is preferably used as a near-infrared cut filter for correcting the luminosity of solid-state imaging devices that use silicon photodiodes that sense infrared light as their light-receiving sections.

[0025] In general, squarylium compounds are easily oxidatively decomposed by light absorption, making them difficult to apply to image display devices and the like that require high light resistance. In addition, when a solution (liquid composition) containing a squarylium compound and a resin is formed into a film, it is prone to generating variations in the film formation state, the state of the squarylium compound present, etc. (also referred to as variations during film formation), which reduces the light absorption capacity. In contrast, the squarylium compounds of the present invention, having chemical structures represented by the following formulas, as described above, can solve the problem of the photooxidative decomposition property of squarylium compounds while suppressing variations during film formation and overcoming the drawback of reduced light absorption capacity. The reason for this is not yet clear, but is presumed to be as follows. Squarylium compounds generally have high planarity and are poorly soluble in organic solvents. Even when dissolved, they tend to form various aggregates, such as H-aggregates. The formation of such aggregates broadens the absorption spectrum of the squarylium compound, reduces lightfastness, and can lead to variations in the film formation state and the state of the squarylium compound. However, both compounds (1) and (3) employ a combination of at least one alkyl group and one aryl group as the total of four substituents on the two disubstituted amino groups in the squarylium structural unit. Furthermore, compound (1) has at least one branched alkyl group having four or more carbon atoms, and compound (3) has a specific metallocene structural unit. These structures make compounds (1) and (3) highly soluble in organic solvents, and even when dissolved at high concentrations, they are unlikely to form aggregates due to moderate steric hindrance. Furthermore, they are also likely to have high compatibility with resins. Therefore, both compounds can be formed into films with minimal variation during film formation, enabling optical filters to exhibit high light absorption capabilities while maintaining excellent lightfastness. In particular, compound (3) having a specific metallocene structure highly suppresses the decomposition of squarylium compounds, enabling further improvement in light resistance. While the reason for this is unclear, it is believed to be due to the deactivation of the excited state of compound (3) and the back electron transfer described below. That is, when compound (3) is photoexcited, the electron-donating metallocene structure quickly injects electrons into the squarylium compound structure corresponding to "Dye" in formula (3), deactivating the excited state. This suppresses the decomposition of compound (3) due to photoexcitation. Furthermore, fluorescence deactivation due to electron transfer typically tends to cause the dye to enter an unstable state (anion radical) when an excess of electrons is given, which promotes dye decomposition. However, compound (3) also promotes back electron transfer from the dye structure converted into anion radical to the metallocene structure. The above-mentioned effects of squarylium compounds are believed to be exhibited not only in liquid compositions but also in melt-kneaded products. Furthermore, the resin composition of the present invention makes it possible to prepare optical filters with various compound concentrations depending on the purpose.

[0026] (Squarylium compound represented by formula (1)) First, the squarylium compound represented by formula (1) will be described. One form of the squarylium compound contained in the resin composition of the present invention is squarylium compound (1) represented by the following formula (1): This compound (1) has at least one branched alkyl group having 4 or more carbon atoms. That is, the groups represented by each symbol in the following formula (1) have at least one branched alkyl group having 4 or more carbon atoms as a substituent on the group represented by each symbol. This compound (1) is constructed by appropriately selecting the groups represented by the symbols in the formula from the ranges described below, and has a symmetric structure with respect to the four-membered carbon ring (R 5 A benzene ring having R 6 and the benzene ring having the same chemical structure are preferred. [ka] In formula (1), R 1 ~R 4 each independently represents an alkyl group or an aryl group, which may have a substituent. 1 ~R 4 at least one of R is an aryl group; 1 ~R 4 At least one of R is an alkyl group. 5 and R 6 Ha-NR 9 R 10 indicates R 9 and R 10 is a hydrogen atom, -COR N , -COOR N , -CON(R N )2 or -SO2R N indicates R N represents a hydrogen atom, or an alkyl or aryl group which may have a substituent. 7 and R 8 represents a substituent, and m and n are integers of 0 to 3.

[0027] R 1 ~R4 The alkyl group may be a straight chain, a branched chain, or a cyclic chain. A straight chain or branched chain is preferred, and a branched chain is particularly preferred. The number of carbon atoms in the alkyl group is not particularly limited and is usually preferably selected from the range of 1 to 40. The lower limit is more preferably 3 or more, even more preferably 5 or more, and particularly preferably 8 or more. The upper limit is more preferably 35 or less, and even more preferably 30 or less. Within the above range, the number of carbon atoms in the branched chain alkyl group is more preferably selected from the range of 3 to 40. In the branched chain alkyl group, the lower limit of the number of carbon atoms is usually more preferably 4 or more, particularly preferably 6 or more, and most preferably 8 or more. The upper limit is usually more preferably 35 or less, and particularly preferably 30 or less. However, from the viewpoints of optical properties such as light absorption ability and light resistance, as well as solubility in organic solvents and compatibility with resins, the number of carbon atoms in the branched chain alkyl group is more preferably in the range of 6 to 35, particularly preferably in the range of 8 to 30, and most preferably in the range of 8 to 24. On the other hand, from a comprehensive viewpoint including ease of synthesis (cost) while maintaining optical properties, solubility, and compatibility, a range of 6 to 24 is more preferable, and a range of 8 to 16 is particularly preferable. The number of branches in the branched alkyl group is preferably 2 to 10, and more preferably 2 to 8, for example. R 1 ~R 4 The aryl group which can be taken as may be a group having a monocyclic structure or a group having a polycyclic structure (such as a fused ring structure or a bridged ring structure), with a group having a monocyclic structure being preferred. The number of carbon atoms in the aryl group is not particularly limited, but is preferably 6 to 30, more preferably 6 to 20, still more preferably 6 to 12, and particularly preferably 6. Examples of the aryl group include groups consisting of a benzene ring and a naphthalene ring, with a group consisting of a benzene ring being more preferred.

[0028] R 1 ~R 4Each of the alkyl group and aryl group that can be taken as may have at least one substituent X, and when having a plurality of substituents X, adjacent substituents may be bonded to each other to form a ring structure. The number of substituents X in one alkyl group is not particularly limited and can be, for example, the same as p in formula (2) described below. The position to which the substituent X is bonded in the alkyl group is not particularly limited and can be determined appropriately. Furthermore, the number of substituents X and the position to which the substituent X is bonded in one aryl group are not particularly limited and are the same as p and q and the substitution position in formula (2) described below.

[0029] - Substituent X - The substituent X is not particularly limited, and examples thereof include alkyl groups (methyl groups, ethyl groups, propyl groups, isopropyl groups, butyl groups, t-butyl groups, isobutyl groups, pentyl groups, hexyl groups, octyl groups, dodecyl groups, trifluoromethyl groups, etc.), cycloalkyl groups (cyclopentyl groups, cyclohexyl groups, etc.), alkenyl groups (vinyl groups, allyl groups, etc.), alkynyl groups (ethynyl groups, propargyl groups, etc.), aryl groups (phenyl groups, naphthyl groups, etc.), heteroaryl groups (furyl groups, thienyl groups, pyridyl groups, pyridazyl groups, pyrimidyl groups, pyrazyl groups, triaryl groups, etc.), and the like. pyrrolidyl group, imidazolyl group, pyrazolyl group, thiazolyl group, benzimidazolyl group, benzoxazolyl group, benzothiazolyl group, quinazolyl group, phthalazyl group, etc.), heterocyclic group (also called (non-aromatic) heterocyclic group, for example, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy group (methoxy group, ethoxy group, propyloxy group, etc.), cycloalkoxy group (cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (phenoxy group, naphthyloxy group, etc.), heteroaryloxy group (aromatic heterocyclic oxy group ), heterocyclic oxy groups (non-aromatic heterocyclic oxy groups), alkylthio groups (methylthio groups, ethylthio groups, propylthio groups, etc.), cycloalkylthio groups (cyclopentylthio groups, cyclohexylthio groups, etc.), arylthio groups (phenylthio groups, naphthylthio groups, etc.), heteroarylthio groups (aromatic heterocyclic thio groups), heterocyclic thio groups (non-aromatic heterocyclic thio groups), alkoxycarbonyl groups (methyloxycarbonyl groups, ethyloxycarbonyl groups, butyloxycarbonyl groups, octyloxycarbonyl groups, etc.), aryloxycarbonyl groups (phenyloxycarbonyl groups, a cyclohexyl group, an octyl group, a phenyl group, a 2-pyridyl group, etc.), an acyl group (an acetyl group, an ethyl group, a propyl group, a cyclohexyl group, an octyl group, a 2-ethylhexyl group, etc.), an aryl group (an aryl group, an ...phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, phenylcarbonyloxy group, etc.), acylamino group (acetylamino group, ethylcarbonylamino group, butylcarbonylamino group, octylcarbonylamino group, phenylcarbonylamino group, etc.), amido group (methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, sulfonylamide groups (methylsulfonylamino groups, octylsulfonylamino groups, 2-ethylhexylsulfonylamino groups, trifluoromethylsulfonylamino groups, etc.), carbamoyl groups (aminocarbonyl groups, methylaminocarbonyl groups, dimethylaminocarbonyl groups, propylaminocarbonyl groups, pentylaminocarbonyl groups, etc.), , cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido groups (methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), alkylsulfonyl groups (methylsulfonyl group, ethylsulfonyl group, butyl sulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, etc.), arylsulfonyl group (phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (amino group, ethylamino group, dimethylamino group, butylamino group, dibutylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), alkylsulfonyloxy group (methanesulfonyloxy), cyano group, nitro group, halogen atom (fluorine atom, chlorine atom,bromine atom, etc.), hydroxy group, sulfo group, carboxy group, etc.

[0030] The number of carbon atoms in the above group as the substituent X is not particularly limited, but can be set, for example, within the following range. The number of carbon atoms in the alkyl group is 1 ~R 4 The number of carbon atoms in the alkenyl group may be within the same range as the number of carbon atoms in the aryl group that can be taken as the alkyl group, or alternatively, may be 1 to 20 (preferably 1 to 15, more preferably 1 to 8). The number of carbon atoms in the alkenyl group is preferably 2 to 20, more preferably 2 to 12, and even more preferably 2 to 8. The number of carbon atoms in the alkynyl group is preferably 2 to 40, more preferably 2 to 30, and particularly preferably 2 to 25. The alkyl group, alkenyl group, and alkynyl group may each be linear, branched, or cyclic, and linear or branched is preferred. The aryl group includes a monocyclic or fused ring group, and preferably has 6 to 30 carbon atoms, more preferably 6 to 20, and even more preferably 6 to 12. The heteroaryl group includes a monocyclic or fused ring group, and preferably has a monocyclic ring or a group having 2 to 8 fused rings, and more preferably has a monocyclic ring or a group having 2 to 4 fused rings. The number of heteroatoms constituting the ring of the heteroaryl group is preferably 1 to 3. Examples of heteroatoms constituting the ring of the heteroaryl group include a nitrogen atom, an oxygen atom, and a sulfur atom. The heteroaryl group is preferably a group consisting of a 5-membered or 6-membered ring. The number of carbon atoms constituting the ring of the heteroaryl group is preferably 3 to 30, more preferably 3 to 18, and even more preferably 3 to 12. The heterocyclic group has the same meaning as the heteroaryl group above, except that it does not have aromaticity. The alkyl group in a substituent containing an alkyl group such as an alkoxy group has the same meaning as the alkyl group described above. Furthermore, the aryl group or heteroaryl group in a substituent containing an aryl group or heteroaryl group such as an aryloxy group or heteroaryloxy group has the same meaning as the aryl group or heteroaryl group described above. R 1 ~R 4As the substituent X which the alkyl group and aryl group may have, among the above, an alkyl group, an aryl group, an acyl group, an alkoxy group, an acylamino group or a sulfonylamino group is preferred.

[0031] R 1 ~R 4 At least one of R is an aryl group and at least one is an alkyl group. 1 ~R 4 The number of aryl groups that can be used as R is 3 or less, preferably 2 or 3, and more preferably 2. 1 ~R 4 The number of alkyl groups that can be used as R is 3 or less, but is preferably 1 or 2, and more preferably 2. 1 ~R 4 When R has two alkyl groups and two aryl groups, 1 and R 2 is an aryl group, R 1 and R 3 and R is an aryl group. 1 ~R 4 When has a plurality of alkyl groups or aryl groups, the plurality of alkyl groups or aryl groups may be the same or different. From the viewpoint of synthetic simplicity, R 1 and R 3 is an aryl group, and R 1 and R 2 is preferably an alkyl group, and R 1 and R 3 are the same aryl group, and R 2 and R 4 are most preferably the same alkyl group.

[0032] R 5 and R 6 are each independently -NR 9 R 10 where R 9 and R 10 are each independently a hydrogen atom, -COR N , -COORN , -CON(R N )2 and -SO2R N -NR 9 R 10 In the formula, R bonded to the same nitrogen atom 9 and R 10 are selected appropriately, but R bonded to the same nitrogen atom 9 and R 10 Preferably, one of R is a hydrogen atom. This forms an intramolecular hydrogen bond with the oxygen atom bonded to the four-membered carbon ring, making the compound (1) itself rigid and significantly improving its light resistance. 9 and R 10 The other is -COR N , -COOR N , -CON(R N )2 and -SO2R N Selected from -COR N or -SO2R N In compound (1), R 5 and R 6 are the different structures of -NR 9 R 10 may be -NR 9 R 10 It is preferable that: Above R N R represents a hydrogen atom, an alkyl group, or an aryl group, and in compound (1), an alkyl group or an aryl group is preferred, and an alkyl group is more preferred. N The alkyl group and aryl group that can be taken as R are not particularly limited, but 1 ~R 4 Preferably, R has the same meaning as the alkyl group and aryl group that can be taken as R. N The alkyl group and aryl group that can be taken as X may have a substituent. Such a substituent is preferably a group selected from the above-mentioned substituent X, and among them, a halogen atom (particularly a fluorine atom), an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an acyl group, etc. are preferred. The halogen-substituted alkyl group may be one in which some of the hydrogen atoms are substituted, or may be a perhalogenoalkyl group in which all of the hydrogen atoms are substituted. -CON(R N )2 has two R N may be the same or different from each other.

[0033] R 7 and R 8 R each independently represents a substituent. 7 and R 8 The substituent that can be taken as is not particularly limited, and examples thereof include groups selected from the above-mentioned substituents X. Among these, an alkenyl group, a halogen atom, an alkyl group, an acyl group, an alkoxy group, an acylamino group, a sulfonylamino group, or a hydroxy group is preferred. R 7 and R 8 The substituents that can be used as R may form a ring. For example, multiple R 7 and R 8 may be bonded to each other to form a fused ring together with the benzene ring. For example, in the exemplary compound A-15 described below, two ethylene groups bonded to the same benzene ring are bonded to form a benzene ring (i.e., a naphthalene ring) fused with the benzene ring. The ring formed in this case is not particularly limited, and may be a hydrocarbon ring or a hetero ring, or may be an aliphatic ring or an aromatic ring. R 7 and R 8 The substituents which may be present may further have a substituent, and examples of the substituents which may further have include groups selected from the above-mentioned substituents X.

[0034] m and n each independently represent an integer of 0 to 3, and are preferably 0 or 1. When m and n are 2 or 3, a plurality of R 7 and R 8 may be the same or different.

[0035] Compound (1) has at least one branched alkyl group having 4 or more carbon atoms as a group represented by each symbol in the above formula (1) or as a substituent on a group represented by each symbol. The number of carbon atoms in the branched alkyl group is not particularly limited as long as it is 4 or more. 1 ~R4 It is preferable that the number of carbon atoms of the branched alkyl group is in the same range as that of the branched alkyl group. The total number of branched alkyl groups in compound (1) is not particularly limited, but from the viewpoint of optical properties and solubility, it is preferably 2 or more, more preferably 2 to 6, more preferably 2 to 4, and even more preferably 2 or 4. In compound (1), the branched alkyl group is R 1 ~R 4 , R 7 , R 8 , R 9 and R 10 or as a substituent on at least one of these, and R 1 ~R 4 , R 9 and R 10 More preferably, R 2 , R 4 , R 9 and R 10 It is more preferred that it is incorporated as at least one of the following:

[0036] In the compound (1), the groups represented by the symbols in the formula (1) can be used in appropriate combination, and it is preferable to use preferred groups in combination.

[0037] - A squarylium compound represented by formula (2) - The compound (1) is preferably a squarylium compound represented by the following formula (2) (sometimes referred to as compound (2)), provided that the squarylium compound represented by formula (2) has at least one branched alkyl group having 4 or more carbon atoms. [ka] In formula (2), R 2 and R 4 Each R independently represents an alkyl group. 11 and R 12 represents a substituent, and p and q are integers of 0 to 5.5 ~R 8 , m and n are R in the above formula (1) 5 ~R 8 , m and n.

[0038] R 2 and R 4 The alkyl group that can be taken as R in formula (1) 1 ~R 4 The alkyl group has the same meaning as the alkyl group which can be taken as the alkyl group. R 11 and R 12 R each independently represents a substituent. 11 and R 12 Possible substituents for R 1 ~R 4 Specific examples include groups selected from the above-mentioned substituents X. Among these, an alkyl group, an aryl group, an acyl group, an alkoxy group, an acylamino group, or a sulfonylamino group is preferred. p and q each independently represent an integer of 0 to 5, preferably 0 to 3, more preferably 0 to 2, and even more preferably 1. When p and q are integers of 2 or more, a plurality of R 11 and R 12 may be the same or different. 11 and R 12 The position at which is bonded is not particularly limited, and may be, for example, any of the ortho-position (2nd position), meta-position (3rd position), or para-position (4th position) relative to the ring-constituting carbon atom (1st position) bonded to the nitrogen atom of each benzene ring, with the para-position being preferred. R 5 ~R 8 , m and n are R in formula (1), respectively. 5 ~R 8 , m and n.

[0039] Compound (2) has at least one branched alkyl group having 4 or more carbon atoms as a group represented by each symbol in the above formula (2) or as a substituent on a group represented by each symbol. The number of carbon atoms in the branched alkyl group and the total number of branched alkyl groups in compound (2) are synonymous with the number of carbon atoms and the total number of branched alkyl groups in compound (1) described above. In compound (2), the branched alkyl group is R 2 , R 4 , R 7 , R 8 , R 9 , R 10 , R 11 and R 12 or as a substituent on at least one of these, and R 2 , R 4 , R 9 and R 10 More preferably, R 2 , R 4 , R 9 and R 10 Among them, R 2 and R 4 It is more preferred that it is incorporated as at least one of the following: In the compound (2), the groups represented by the symbols in the formula (2) can be used in appropriate combination, and it is preferable to use preferred groups in combination.

[0040] Specific examples of squarylium compounds represented by formula (1) are shown below, but the present invention is not limited thereto. The following specific examples are shown as tautomeric structures of squarylium compounds represented by formula (1). In the following specific examples, -C a H (2a+1) The alkyl group represented by the formula (I) is a straight-chain alkyl group, and Me is methyl.

[0041] [ka]

[0042] [ka]

[0043] (Squarylium compound represented by formula (3)) Another form of the squarylium compound contained in the resin composition of the present invention is squarylium compound (3) represented by formula (3) below. This compound (3) has at least one group represented by formula (4M) below. That is, it is a compound in which at least one hydrogen atom of a compound represented by formula (4) is substituted with a group represented by formula (4M). This compound (3) preferably has at least one branched alkyl group having 4 or more carbon atoms as a substituent on the group represented by each symbol in formula (4) below. This compound (3) is constructed by appropriately selecting the groups represented by the symbols in the formula from the ranges described below, and has a symmetric structure with respect to the four-membered carbon ring in formula (4) (R 5 A benzene ring having R 6 and the benzene ring having the same chemical structure are preferred.

[0044] [ka] In formula (3), Dye represents a structural portion obtained by removing n1 hydrogen atoms from a squarylium compound represented by formula (4) below (sometimes referred to as compound (4)), and Q 1 represents a group represented by the following formula (4M), wherein n1 is an integer of 1 to 6.

[0045] - A squarylium compound represented by formula (4) - The compound (4) from which the dye of the compound (3) is derived is represented by the following formula (4). [ka] In formula (4), R 1 ~R 4 represents an alkyl group or an aryl group which may have a substituent, provided that R 1 ~R 4 at least one of R is an aryl group; 1 ~R 4 At least one of R is an alkyl group. 5and R 6 Ha-NR 9 R 10 indicates R 9 and R 10 is a hydrogen atom, -COR N , -COOR N , -CON(R N )2 or -SO2R N indicates R N represents a hydrogen atom or an alkyl or aryl group which may have a substituent. 7 and R 8 represents a substituent, and m and n are integers of 0 to 3.

[0046] Compound (4) is the same as compound (1) except that it does not need to have a branched alkyl group having 4 or more carbon atoms. 1 ~R 8 , m and n are the R 1 ~R 8 , m and n. However, R 1 ~R 4 When a group represented by formula (4M) is introduced into an alkyl group that can be taken as the alkyl group, the alkyl group is preferably a linear alkyl group, and the number of carbon atoms therein is preferably in the range of 1 to 10, more preferably in the range of 2 to 6, within the above range. Also, -NR 9 R 10 When a group represented by formula (4M) is introduced into R 9 and R 10 It can be taken as -COR N , -COOR N , -CON(R N )2 and -SO2R N R has N is preferably a hydrogen atom or an alkyl group. Compound (4) does not necessarily have to have a branched alkyl group having 4 or more carbon atoms, but preferably has at least one branched alkyl group having 4 or more carbon atoms. The embodiment in which compound (4) has a branched alkyl group having 4 or more carbon atoms is synonymous with the embodiment in which compound (1) has a branched alkyl group having 4 or more carbon atoms, and in this case, compound (4) is preferably synonymous with compound (1). In the compound (4), the groups represented by the symbols in the formula (4) can be used in appropriate combination, and it is preferable to use preferred groups in combination.

[0047] The part (atom) obtained by removing the hydrogen atom from compound (4) becomes the bond to L in formula (4M) below (the bond indicated by "*" in the formula). The manner in which hydrogen atoms are removed from compound (4) is not particularly limited, and any suitable hydrogen atoms can be removed. For example, R 1 ~R 8 and a hydrogen atom possessed by each group represented by any one of the following: 5 or R 6 and R 1 ~R 6 A hydrogen atom contained in each group represented by any one of the following is preferred. The number of hydrogen atoms to be removed is not particularly limited, but is the same as n1 described below. The manner in which a hydrogen atom is removed from compound (4) is not particularly limited, and examples thereof include R 1 and R 2 the mode of removing one hydrogen atom from each group represented by R 1 and R 3 Each group represented by R 2 and R 4 the mode of removing one hydrogen atom from each group represented by R 5 and R 6 and a combination of these embodiments. 1 and R 3 Each group represented by R 2 and R 4the mode of removing one hydrogen atom from each group represented by R 5 and R 6 More preferred examples include an embodiment in which one hydrogen atom is removed from each group represented by R 5 and R 6 A preferred embodiment is one in which one hydrogen atom is removed from each group represented by the formula:

[0048] - A squarylium compound represented by formula (5) - The compound (4) is preferably a squarylium compound represented by the following formula (5) (sometimes referred to as compound (5)). [ka] In formula (5), R 2 and R 4 Each R independently represents an alkyl group. 11 and R 12 represents a substituent, and p and q are integers of 0 to 5. 5 ~R 8 , m and n are R in formula (4) 5 ~R 8 , m and n. R 2 and R 4 The alkyl group that can be taken as R in formula (1) 1 ~R 4 The alkyl group has the same meaning as the alkyl group which can be taken as the alkyl group. R 11 and R 12 R each independently represents a substituent. 11 and R 12 Possible substituents for R 1 ~R 4 Specific examples include groups selected from the above-mentioned substituents X. Among these, an alkyl group, an aryl group, an acyl group, an alkoxy group, an acylamino group, or a sulfonylamino group is preferred. p and q each independently represent an integer of 0 to 5, preferably 0 to 3, more preferably 0 to 2, and even more preferably 1. When p and q are integers of 2 or more, a plurality of R 11 and R 12 may be the same or different. 11 and R 12 The position at which is bonded is not particularly limited, and may be, for example, either the meta position (3rd position) or the para position (4th position) relative to the ring-constituting carbon atom (1st position) bonded to the nitrogen atom of each benzene ring, with the para position being preferred. R 5 ~R 8 , m and n are R in formula (4), respectively. 5 ~R 8 , m and n.

[0049] Compound (5) is a preferred embodiment of compound (4), but can also be said to be the same as compound (2) above, except that it does not necessarily have a branched alkyl group having 4 or more carbon atoms. However, compound (5) preferably has at least one branched alkyl group having 4 or more carbon atoms. An embodiment in which compound (5) has a branched alkyl group having 4 or more carbon atoms is synonymous with an embodiment in which compound (4) has a branched alkyl group having 4 or more carbon atoms, and in this case, compound (5) is preferably synonymous with compound (2). In the compound (5), the groups represented by the symbols in the formula (5) can be applied in appropriate combination, and it is preferable to apply preferred groups in combination.

[0050] The manner in which hydrogen atoms are removed from compound (5) is not particularly limited, and any suitable hydrogen atoms can be removed. For example, R 2 , R 4 ~R 8 and R 11 ~R 12 and a hydrogen atom possessed by each group represented by any one of the following: 5 or R 6 or R 11 or R 12The number of hydrogen atoms to be removed is not particularly limited, but is the same as n1, which will be described later. The manner in which a hydrogen atom is removed from compound (5) is not particularly limited, and examples thereof include R 2 and R 4 the mode of removing one hydrogen atom from each group represented by R 5 and R 6 Preferred examples include an embodiment in which one hydrogen atom is removed from each group (preferably a group other than a hydrogen atom) represented by the following formula: and further, a combination of these embodiments.

[0051] In formula (3), n1 represents the number of Q1s bonded to Dye, and is usually selected appropriately from the range of 1 or more and not more than the number of hydrogen atoms possessed by compound (4). For example, n1 can be an integer of 1 to 6, preferably an integer of 1 to 4, and more preferably 1 or 2. When n1 is an integer of 2 or more, multiple Q1s can be bonded to Dye. 1 may be the same or different.

[0052] Q in equation (3) 1 represents a group represented by the following formula (4M). [ka] In formula (4M), L represents a single bond or a divalent linking group that is not conjugated with the dye. 1m ~R 9m represents a hydrogen atom or a substituent. M represents Fe, Co, Ni, Ti, Cu, Zn, Zr, Cr, Mo, Os, Mn, Ru, Sn, Pd, Rh, V, or Pt. * represents the bond to the dye.

[0053] In compound (3), R in formula (4) 1 ~R 8 When a group represented by the above formula (4M) is introduced into each group represented by any one of the following formulas, L in formula (4M) is interpreted as a single bond. In compound (3), when L in formula (4M) is a divalent linking group, Dye is a structure extending up to the portion (atom) where the conjugated structure is interrupted by the linkage with L. In other words, when L is a divalent linking group rather than a single bond, the bond portion of L to Dye does not form a conjugated structure. In other words, when a conjugated structure continues from Dye to the group represented by formula (4M) (the metallocene structural portion) (i.e., when a conjugated structure continues from Dye to the metallocene skeleton in formula (4M)), L becomes a single bond. Here, the conjugated structure refers to a structure that forms a bonded p-orbital system with delocalized electrons in alternating single bonds and multiple bonds, and also includes a structure containing a p-orbital donor group, a p-orbital donor atom, or a p-orbital donor group and a p-orbital donor atom. Examples of p-orbital donor groups include a carbonyl group and a sulfonyl group. A p-orbital donor atom refers to an atom having two lone electron pairs, one of which occupies a p-orbital. Examples of atoms that can be p-orbital donors include an oxygen atom, a nitrogen atom, and a sulfur atom. When a p-orbital donor group and a p-orbital donor atom are contained, examples include a structure formed by combining a plurality of p-orbital donor atoms and p-orbital donor groups (preferably an integer of 2 to 10). For example, divalent groups represented by -O-CO-, -NH-CO-, -NH-SO2-, -NH-CO-NH-, etc. are groups that form a conjugated structure. In the present invention, when L in formula (4M) is a single bond, the cyclopentadienyl ring (R in formula (4M)) directly bonded to Dye is a cyclopentadienyl ring. 1m The ring having the formula (I) is not included in the conjugated structure conjugated with the dye.

[0054] In light of the above, the divalent linking group that can be used as L is not particularly limited as long as it is a linking group that is not conjugated with the dye, and may contain the above-mentioned conjugated structure inside it or at the end of the cyclopentadiene ring in formula (4M). Examples of the divalent linking group include an alkylene group having 1 to 20 carbon atoms, an arylene group having 6 to 20 carbon atoms, a divalent heterocyclic group obtained by removing two hydrogen atoms from a heterocycle, -CH=CH-, -CO-, -CS-, -NR- (R represents a hydrogen atom or a monovalent substituent), -O-, -S-, -SO2- or -N=CH-, and a divalent linking group formed by combining a plurality of these (preferably 2 to 6 groups) that is not conjugated with the dye. Preferably, the linking group is a divalent linking group selected from the group consisting of an alkylene group having 1 to 8 carbon atoms, an arylene group having 6 to 12 carbon atoms, -CH=CH-, -CO-, -NR- (wherein R is as defined above), -O-, -S-, -SO2-, and -N=CH-, or a combination of two or more (preferably 2 to 6) groups selected from this group, which does not conjugate with the dye. Particularly preferred are alkylene groups having 1 to 4 carbon atoms, a phenylene group, a group selected from the group consisting of -CO-, -NH-, -O-, and -SO2-, or a combination of two or more (preferably 2 to 6) groups selected from this group, which does not conjugate with the dye. The combined divalent linking group is not particularly limited, but is preferably a group containing -CO-, -NH-, -O-, or -SO2-, and examples thereof include linking groups containing a group formed by combining two or more of -CO-, -NH-, -O-, or -SO2-, or linking groups formed by combining at least one of -CO-, -NH-, -O-, and -SO2- with an alkylene group or an arylene group, which do not conjugate with the dye. Examples of linking groups containing a group formed by combining two or more of -CO-, -NH-, -O-, or -SO2- include linking groups containing -COO-, -OCO-, -CONH-, -NHCOO-, -NHCONH-, or -SONH-, which do not conjugate with the dye. Examples of the linking group formed by combining at least one of -CO-, -NH-, -O-, and -SO2- with an alkylene group or an arylene group include linking groups that are not conjugated with the dye and that are formed by combining -CO-, -COO-, or -CONH- with an alkylene group or an arylene group. The substituent that can be taken as R is not particularly limited, and examples thereof include the above-mentioned substituent X.

[0055] L is preferably a single bond, or a group selected from the group consisting of an alkylene group having 1 to 8 carbon atoms, an arylene group having 6 to 12 carbon atoms, -CH=CH-, -CO-, -NR- (wherein R is as defined above), -O-, -S-, -SO2-, and -N=CH-, or a group formed by combining two or more groups selected from this group.

[0056] L may have one or more substituents. The substituent that L may have is not particularly limited and has the same meaning as the above-mentioned substituent X, for example. When L has multiple substituents, the substituents bonded to adjacent atoms may further bond to each other to form a ring structure.

[0057] The alkylene group that can be taken as L may be any of linear, branched, and cyclic, so long as it has 1 to 20 carbon atoms, and examples thereof include methylene, ethylene, propylene, methylethylene, methylmethylene, dimethylmethylene, 1,1-dimethylethylene, butylene, 1-methylpropylene, 2-methylpropylene, 1,2-dimethylpropylene, 1,3-dimethylpropylene, 1-methylbutylene, 2-methylbutylene, 3-methylbutylene, 4-methylbutylene, 2,4-dimethylbutylene, 1,3-dimethylbutylene, pentylene, Examples include hexylene, heptylene, octylene, ethane-1,1-diyl, propane-2,2-diyl, cyclopropane-1,1-diyl, cyclopropane-1,2-diyl, cyclobutane-1,1-diyl, cyclobutane-1,2-diyl, cyclopentane-1,1-diyl, cyclopentane-1,2-diyl, cyclopentane-1,3-diyl, cyclohexane-1,1-diyl, cyclohexane-1,2-diyl, cyclohexane-1,3-diyl, cyclohexane-1,4-diyl, and methylcyclohexane-1,4-diyl. When L is a linking group containing at least one of -CO-, -CS-, -NR- (wherein R is as defined above), -O-, -S-, -SO2-, and -N=CH- in an alkylene group, the group such as -CO- may be incorporated at any position in the alkylene group, and the number of groups incorporated is not particularly limited.

[0058] The arylene group that can be used as L is not particularly limited as long as it is a group derived by removing a hydrogen atom from an aryl group having 6 to 20 carbon atoms. The heterocyclic group that can be used as L is not particularly limited, and examples thereof include groups consisting of an aliphatic heterocycle or an aromatic heterocycle. As the heterocyclic group, a 5-membered or 6-membered ring group is preferable. Examples of the heterocyclic group that can be used as L include groups in which two hydrogen atoms have been removed from a pyrrole ring, a furan ring, a thiophene ring, an imidazole ring, a pyrazole ring, a thiazole ring, an oxazole ring, a triazole ring, an indole ring, an indolenine ring, an indoline ring, a pyridine ring, a pyrimidine ring, a quinoline ring, a benzothiazole ring, a benzoxazole ring, or a pyrazolotriazole ring.

[0059] In formula (4M), the remaining partial structure excluding the linking group L corresponds to a structure (metallocene structural part) obtained by removing one hydrogen atom from a metallocene compound. In the present invention, the metallocene compound that serves as the metallocene structural part is not particularly limited, and any known metallocene compound can be used as long as it is a compound that conforms to the partial structure defined by formula (4M) above (a compound in which a hydrogen atom is bonded instead of L). The metallocene structural part defined by formula (4M) will be specifically described below.

[0060] In formula (4M), R 1m ~R 9m R each represents a hydrogen atom or a substituent. 1m ~R 9m The substituents that can be used as R are not particularly limited, but can be selected from the substituents X, for example. 1m ~R 9mare each preferably a hydrogen atom, a halogen atom, an alkyl group, an acyl group, an alkoxy group, an amino group, or an amide group, more preferably a hydrogen atom, a halogen atom, an alkyl group, an acyl group, or an alkoxy group, still more preferably a hydrogen atom, a halogen atom, an alkyl group, or an acyl group, particularly preferably a hydrogen atom, a halogen atom, or an alkyl group, and most preferably a hydrogen atom.

[0061] R 1m ~R 9m The alkyl group that can be used as R 1 Among the alkyl groups that can be taken as a substituent, alkyl groups having 1 to 8 carbon atoms are preferred, and examples thereof include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, isobutyl, pentyl, tert-pentyl, hexyl, octyl, and 2-ethylhexyl. This alkyl group may have a halogen atom as a substituent. Examples of the alkyl group substituted with a halogen atom include chloromethyl, dichloromethyl, trichloromethyl, bromomethyl, dibromomethyl, tribromomethyl, fluoromethyl, difluoromethyl, trifluoromethyl, 2,2,2-trifluoroethyl, perfluoroethyl, perfluoropropyl, and perfluorobutyl. Also, R 1mIn the alkyl groups which can be taken as examples such as above, at least one methylene group forming the carbon chain may be substituted with -O- or -CO-. Examples of alkyl groups in which a methylene group is substituted with -O- include alkyl groups in which a terminal methylene group is substituted, such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, sec-butoxy, tert-butoxy, 2-methoxyethoxy, chloromethyloxy, dichloromethyloxy, trichloromethyloxy, bromomethyloxy, dibromomethyloxy, tribromomethyloxy, fluoromethyloxy, difluoromethyloxy, trifluoromethyloxy, 2,2,2-trifluoroethyloxy, perfluoroethyloxy, perfluoropropyloxy, and perfluorobutyloxy, as well as alkyl groups in which an internal methylene group of the carbon chain, such as 2-methoxyethyl, is substituted. Examples of the alkyl group in which a methylene group is substituted with -CO- include acetyl, propionyl, monochloroacetyl, dichloroacetyl, trichloroacetyl, trifluoroacetyl, propan-2-one-1-yl, and butan-2-one-1-yl.

[0062] In formula (4M), M is an atom that can constitute a metallocene compound and represents Fe, Co, Ni, Ti, Cu, Zn, Zr, Cr, Mo, Os, Mn, Ru, Sn, Pd, Rh, V, or Pt. Among these, M is preferably Fe, Ti, Co, Ni, Zr, Ru, or Os, more preferably Fe, Ti, Ni, Ru, or Os, still more preferably Fe or Ti, and most preferably Fe.

[0063] The group represented by formula (4M) includes L, R 1m ~R 9m and M are preferably a group formed by combining the preferred ones of M and M, and for example, L is a single bond, or a group selected from the group consisting of an alkylene group having 2 to 8 carbon atoms, an arylene group having 6 to 12 carbon atoms, -CH=CH-, -CO-, -NR- (R is as defined above), -O-, -S-, -SO2- and -N=CH-, or a group formed by combining two or more groups selected from this group, and R 1m ~R 9mExamples of the group include a group formed by combining a hydrogen atom, a halogen atom, an alkyl group, an acyl group, or an alkoxy group with Fe as M.

[0064] Specific examples of squarylium compounds represented by formula (3) are shown below, but the present invention is not limited thereto. The following specific examples are shown as tautomeric structures of squarylium compounds represented by formula (1). In the following specific examples, -C a H (2a+1) The alkyl group represented by the formula (I) is a straight-chain alkyl group, and Me is methyl.

[0065] [ka]

[0066] [ka]

[0067] The content of the squarylium compound in the resin composition of the present invention is not particularly limited and is set appropriately taking into consideration the type or solubility of the squarylium compound, the required optical properties, etc. The content is, for example, preferably 0.005 to 15 parts by mass, more preferably 0.01 to 10 parts by mass, and even more preferably 0.01 to 5 parts by mass, relative to 100 parts by mass of the binder resin described below. The resin composition of the present invention can also have a high squarylium compound content, and in this case, it can be set to, for example, 10 to 30 parts by mass. Furthermore, squarylium compounds are easily soluble in solvents, and for example, in the "Solubility Evaluation" section in the Examples described below, they exhibit a solubility of 0.01 parts by mass or more in 100 parts by mass of a toluene / cyclohexanone mixed solvent. When the optical filter contains two or more squarylium compounds, the above content is the total content of these compounds. In addition, when the optical filter of the present invention also serves as a polarizing plate protective film or a pressure-sensitive adhesive layer, as described below, the content of the dye (squarylium compound) may also be within the above range.

[0068] (Method for synthesizing squarylium compounds) The squarylium compounds represented by each formula can be synthesized according to known methods, for example, according to the synthesis methods described in Patent Documents 1 to 3, and further according to the synthesis methods described in the Examples below.

[0069] A preferred synthesis (production) method for the squarylium compound represented by formula (1) includes, for example, a synthesis method (hereinafter sometimes referred to as a preferred production method) in which a compound represented by formula (A) below is reacted with squaric acid or a compound represented by formula (B) below. Note that in the formula below, the compound to be reacted with squaric acid is the compound represented by formula (A) below, but this is synonymous with the combination of the compound represented by formula (A) and the compound represented by formula (B1) described below. [ka]

[0070] In formula (A), formula (B) and formula (1), R 1 ~R 4 represents an alkyl group or an aryl group which may have a substituent. 5 and R 6 Ha-NR 9 R 10 indicates R 9 and R 10 is a hydrogen atom, -COR N , -COOR N , -CON(R N )2 or -SO2R N indicates R N represents a hydrogen atom or an alkyl or aryl group which may have a substituent. 7 and R 8 represents a substituent, and m and n are integers of 0 to 3. Each symbol in formula (A), formula (B) and formula (1) is the same as the corresponding symbol in formula (1) above.

[0071] However, when the compound represented by formula (A) is reacted with squaric acid, in the combination of the compound represented by formula (A) to be reacted with squaric acid, R 1 and R 2 at least one of R is an aryl group; 1 and R 2 At least one of the compounds represented by formula (A) has at least one branched alkyl group having 4 or more carbon atoms. It is preferable that the two molecules of the compound represented by formula (A) to be reacted with squaric acid have the same chemical structure. In addition, in the combination of the compound represented by formula (A) and the compound represented by formula (B1) described later, the above "R 1 and R 2 " to "R 1 ~R 4 " and "at least one of the compounds represented by formula (A)" shall be read as "at least one of the compounds represented by formula (A) and formula (B1)." When a compound represented by formula (A) and a compound represented by formula (B) are reacted with each other, in the combination of the compounds represented by formula (A) or formula (B) to be reacted with each other, R 1 ~R 4 at least one of R is an aryl group; 1 ~R 4 At least one of the groups is an alkyl group, and at least one of the compound represented by formula (A) and the compound represented by formula (B) has at least one branched alkyl group having 4 or more carbon atoms. It is preferable that the compound represented by formula (A) and the aminobenzene moiety in formula (B) have different chemical structures. The squarylium compound represented by formula (1) has at least one branched alkyl group having 4 or more carbon atoms. In the above combination, the embodiment having an aryl group and an alkyl group, and the embodiment having at least one branched alkyl group having 4 or more carbon atoms are the same as the embodiments in the compound represented by formula (1) above.

[0072] In the above-mentioned preferred production method, the compound to be reacted with the compound represented by formula (A) can be selected depending on the chemical structure of the squarylium compound to be produced. For example, when the squarylium compound represented by formula (1) has a chemical structure symmetrical with respect to the four-membered carbon ring (R 5 A benzene ring having R 6 The compound represented by formula (A) can be reacted with the compound represented by formula (B) when the benzene ring having the same chemical structure as the compound represented by formula (A) has the same chemical structure. However, it is preferable to react squaric acid with two molecules of the compound represented by formula (A) (the compound represented by formula (A) and the compound represented by formula (B1) described below). On the other hand, when the squarylium compound represented by formula (1) has an asymmetric chemical structure with respect to the four-membered carbon ring (when the R 5 A benzene ring having R 6 In the case where the benzene ring having the formula (A) has a different chemical structure from the benzene ring having the formula (B), it is preferable to react the compound represented by formula (A) with the compound represented by formula (B).

[0073] The conditions for reacting the compound represented by formula (A) with squaric acid (dehydration condensation reaction) are not particularly limited as long as the conditions allow the reaction to proceed, and can be set appropriately. The amount of the compound represented by formula (A) used is stoichiometrically 2 moles per mole of squaric acid, but in practice it is preferably 1.5 to 2.5 moles. The reaction temperature is preferably equal to or higher than the boiling point (reflux temperature) of the solvent described below, and is, for example, preferably 50 to 150° C., more preferably 80 to 120° C. The reaction time can be, for example, 0.5 to 20 hours. This reaction is usually carried out in a solvent. The solvent to be used is not particularly limited as long as it does not inhibit the reaction. Among them, a solvent that forms an azeotrope with water generated as a by-product as the reaction proceeds is preferred, and examples thereof include alcohol solvents having 1 to 6 carbon atoms, aromatic hydrocarbon solvents such as benzene, toluene, and xylene, and mixed solvents thereof. In this reaction, it is preferable to remove and separate the by-produced water from the reaction system, and a conventional apparatus, for example, a Dean-Stark apparatus, can be used when heating under reflux. After the reaction, if the produced squarylium compound is dissolved in the reaction solution, the squarylium compound can be obtained as a precipitate by diluting the reaction solution with an alcohol solvent or the like or by cooling the reaction solution. The precipitate can also be purified by a conventional purification method. Regarding the reaction conditions, post-treatment, etc., known synthesis methods can be referred to as appropriate.

[0074] The conditions for reacting the compound represented by formula (A) with the compound represented by formula (B) are not particularly limited and can be appropriately set. For example, the conditions for reacting the compound represented by formula (A) with squaric acid can be mentioned. Note that, for the reaction conditions, post-treatment, etc., known synthesis methods can be referred to as appropriate.

[0075] The compound represented by formula (B) can be synthesized by reacting a compound represented by the following formula (B1) with a compound represented by the following formula (B2). [ka] In formula (B1), each symbol is the same as the corresponding symbol in formula (1) above. In formula (B2), X represents an alkoxy group or a halogen atom. The alkoxy group that can be represented by X is not particularly limited, and examples thereof include R 1 Examples of the substituent X that may be present on the alkyl group or the like include an alkoxy group, among which an alkoxy group having 1 to 8 carbon atoms is preferred, and an alkoxy group having 1 to 4 carbon atoms is more preferred. Examples of the halogen atom that may be present as X include the halogen atom in the substituent X, and a chlorine atom is preferred. X is preferably a methoxy group, an ethoxy group, or a chlorine atom, and the two Xs may be the same or different.

[0076] The conditions for reacting the compound represented by formula (B1) with the compound represented by formula (B2) are not particularly limited as long as the conditions allow the reaction to proceed, and can be set appropriately. The amount of the compound represented by formula (B2) used is stoichiometrically 1 mole per mole of the compound represented by formula (B1), but in practice it is preferably 0.8 to 1.2 moles. The reaction temperature is preferably 20 to 150° C., more preferably 50 to 120° C. The reaction time can be, for example, 0.5 to 20 hours. This reaction is usually carried out in a solvent. The solvent to be used is not particularly limited as long as it does not inhibit the reaction, and preferred examples include the above-mentioned aromatic hydrocarbon solvents. After completion of the reaction between the compound represented by formula (B1) and the compound represented by formula (B2), the resulting compound can be subjected to, for example, hydrolysis reaction in water in the presence of an organic acid such as acetic acid or an inorganic acid such as hydrochloric acid, if necessary, by heating, to obtain the compound represented by formula (B). The resulting compound can be purified by a conventional purification method. Regarding the reaction conditions, post-treatment, etc., known synthesis methods can be referred to as appropriate.

[0077] The above-mentioned preferred production method can synthesize a squarylium compound represented by the above formula (1), formula (2), formula (4), or formula (5). When synthesizing a squarylium compound represented by formula (4) or formula (5), each of the compounds represented by formula (A), formula (B), and formula (B1) does not need to have a branched alkyl group having 4 or more carbon atoms. In the above-mentioned preferred production method, the squarylium compound represented by the above formula (3) can be synthesized by introducing the group represented by the above formula (4M) into each of the compounds represented by the above formula (A), formula (B), and formula (B1) by a conventional method.

[0078] <Resin> The resin composition of the present invention contains a resin (binder) (the binder may contain any conventional component in addition to the polymer. Hereinafter, it may be referred to as a "binder resin"). The resin used in the present invention is preferably transparent, which means that the total light transmittance measured on a test piece having a thickness of 1 mm is usually 70% or more, preferably 80% or more, and more preferably 90% or more. The resin used as the binder in the resin composition of the present invention is not particularly limited, and any resin commonly used as a component of an optical filter can be used without particular limitation. It can be appropriately selected from resins that satisfy the various physical properties required for the application or purpose, such as transparency, refractive index, and processability. The resin may be a thermoplastic resin or a thermosetting resin. Examples of resins include poly(meth)acrylic resins, epoxy resins, enethiol resins, polycarbonate resins, polyether resins, polyarylate resins, polysulfone resins, polyethersulfone resins, polyphenylene resins, polyarylene ether phosphine oxide resins, polyimide resins, polyamideimide resins, polyolefin resins, cycloolefin resins (cyclic olefin resins), polyester resins, polystyrene resins, polyurethane resins, polythiourethane resins, cellulose acylate resins, and episulfide resins. Since the squarylium compound of the present invention exhibits a certain degree of compatibility with hydrophobic resins, hydrophobic resins can also be used in combination. Among the above, preferred examples of the resin contained in the resin composition include polystyrene resin, cellulose acylate resin, poly(meth)acrylic resin, polyester resin, cycloolefin resin, polycarbonate resin, etc., and from the viewpoint of further reducing the fluorescence quantum yield, polystyrene resin or cycloolefin resin is preferred. The squarylium compound represented by the above formula (1) and the squarylium compound represented by the above formula (3) can both be used in appropriate combination with the above resins. Taking one embodiment of a combination of a squarylium compound and a resin as an example, for example, from the viewpoint of compatibility with the resin, the squarylium compound represented by the above formula (1) is preferably combined with, among the above resins, poly(meth)acrylic resin, polystyrene resin, cellulose acylate resin, cycloolefin resin, polycarbonate resin, polyester resin, etc. Furthermore, for example, from the viewpoint of achieving high light resistance, the squarylium compound represented by the above formula (3) is preferably combined with, among the above resins, a hydrophobic resin, and specifically, combinations with polystyrene resin, cycloolefin resin, etc. are more preferred.

[0079] (Polystyrene resin) The polystyrene contained in the polystyrene resin means a copolymer containing 50% by mass or more of a styrene component. In the present invention, only one type of polystyrene may be used, or two or more types may be used in combination. Here, the styrene component is a constituent unit derived from a monomer having a styrene skeleton in its structure. For the purpose of controlling the resin composition or optical filter to a preferred photoelastic coefficient and to a preferred moisture absorption, the polystyrene preferably contains 70% by mass or more, and even more preferably 85% by mass or more, of a styrene component. It is also preferable that the polystyrene is composed only of a styrene component.

[0080] Examples of polystyrene include homopolymers of styrene compounds and copolymers of two or more styrene compounds. Here, the term "styrene compound" refers to a compound having a styrene skeleton in its structure, and includes styrene as well as compounds in which a substituent has been introduced into a portion other than the ethylenically unsaturated bond. Examples of styrene compounds include styrene; alkylstyrenes such as α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 3,5-dimethylstyrene, 2,4-dimethylstyrene, o-ethylstyrene, p-ethylstyrene, and tert-butylstyrene; and substituted styrenes in which a hydroxyl group, an alkoxy group, a carboxyl group, a halogen, or the like has been introduced into the benzene nucleus of styrene, such as hydroxystyrene, tert-butoxystyrene, vinylbenzoic acid, o-chlorostyrene, and p-chlorostyrene. Among these, from the viewpoints of availability and material cost, the polystyrene used in the present invention is preferably a homopolymer of styrene (i.e., polystyrene).

[0081] The components other than the styrene component contained in the polystyrene are not particularly limited. That is, the polystyrene may be a styrene-diene copolymer or a styrene-polymerizable unsaturated carboxylic acid ester copolymer. A mixture of polystyrene and synthetic rubber (e.g., polybutadiene, polyisoprene, etc.) can also be used. High impact polystyrene (HIPS) obtained by graft-polymerizing styrene onto synthetic rubber is also preferred. Also preferred is polystyrene obtained by dispersing a rubber-like elastomer in a continuous phase of a polymer containing a styrene component (e.g., a copolymer of a styrene component and a (meth)acrylic acid ester component) and graft-polymerizing the copolymer onto the rubber-like elastomer (graft-type high impact polystyrene, referred to as "graft HIPS"). Furthermore, so-called styrene-based elastomers can also be suitably used. The polystyrene may be hydrogenated (it may be hydrogenated polystyrene). The hydrogenated polystyrene is not particularly limited, but hydrogenated styrene-diene copolymers such as hydrogenated styrene-butadiene-styrene block copolymer (SEBS) and hydrogenated styrene-isoprene-styrene block copolymer (SEPS), which are resins obtained by adding hydrogen to SBS or SIS, are preferred. The hydrogenated polystyrene may be used alone or in combination of two or more.

[0082] The molecular weight of the polystyrene used in the present invention is appropriately selected depending on the intended use, but the mass average molecular weight (standard polystyrene equivalent) measured by gel permeation chromatography of a tetrahydrofuran solution (or a toluene solution if the polymer is not soluble) is usually in the range of 5,000 to 500,000, preferably 8,000 to 200,000, and more preferably 10,000 to 100,000. A polymer having a molecular weight within the above range can achieve a good balance between high levels of mechanical strength and moldability of the molded article.

[0083] As the polystyrene, a plurality of types having different compositions, molecular weights, etc. can be used in combination. Polystyrene resins can be obtained by known anionic, bulk, suspension, emulsion, or solution polymerization methods. Furthermore, in polystyrene resins, the unsaturated double bonds of the benzene rings of the conjugated dienes or styrene monomers may be hydrogenated. The degree of hydrogenation can be measured by nuclear magnetic resonance (NMR) spectroscopy. As the polystyrene resin, commercially available products may be used, and examples thereof include "CLEAREN 530L" and "CLEAREN 730L" manufactured by Denki Kagaku Kogyo Co., Ltd., "TUFPREN 126S" and "ASAPRENE T411" manufactured by Asahi Kasei Corporation, "KRATON D1102A" and "KRATON D1116A" manufactured by Kraton Polymers Japan, "STYROLUX S" and "STYROLUX T" manufactured by Styrolution, "ASAFLEX 840" and "ASAFLEX 860" manufactured by Asahi Kasei Chemicals Corporation (SBS), "679", "HF77", and "SGP-10" manufactured by PS Japan, "DIC STYRENE XC-515" and "DIC STYRENE XC-535" manufactured by DIC Corporation (general-purpose polystyrene: GPPS), "475D", "H0103", and "HT478" manufactured by PS Japan, and "DIC STYRENE GH-8300-5" manufactured by DIC Corporation (HIPS). Examples of hydrogenated polystyrene resins include the "Tuftec H Series" manufactured by Asahi Kasei Chemicals Corporation, the "Kraton G Series" manufactured by Shell Japan (both of which are SEBS), the "Dynalon" (hydrogenated styrene-butadiene random copolymer) manufactured by JSR Corporation, and the "Septon" (SEPS) manufactured by Kuraray Co., Ltd. Examples of modified polystyrene resins include the "Tuftec M Series" manufactured by Asahi Kasei Chemicals Corporation, the "Epofriend" manufactured by Daicel Corporation, the "Polar Group Modified Dynalon" manufactured by JSR Corporation, and the "Reseda" manufactured by Toagosei Co., Ltd.

[0084] (cycloolefin resin) The cyclic olefin compound forming the cycloolefin polymer (also referred to as cyclic polyolefin) contained in the cycloolefin resin is not particularly limited as long as it is a compound having a ring structure containing a carbon-carbon double bond, and examples thereof include norbornene compounds, monocyclic olefin compounds other than norbornene compounds, cyclic conjugated diene compounds, and vinyl alicyclic hydrocarbon compounds. Examples of cycloolefin polymers contained in cycloolefin resins include (R1) polymers containing structural units derived from norbornene compounds, (R2) polymers containing structural units derived from monocyclic olefin compounds other than norbornene compounds, (R3) polymers containing structural units derived from cyclic conjugated diene compounds, (R4) polymers containing structural units derived from vinyl alicyclic hydrocarbon compounds, and hydrogenated polymers containing structural units derived from each of the compounds (R1) to (R4). In the present invention, the polymers containing structural units derived from norbornene compounds and the polymers containing structural units derived from monocyclic olefin compounds include ring-opened polymers of each compound.

[0085] The cycloolefin polymer is not particularly limited, but is preferably a polymer having a structural unit derived from a norbornene compound, represented by the following general formula (A-II) or (A-III): The polymer having the structural unit represented by the following general formula (A-II) is an addition polymer of a norbornene compound, and the polymer having the structural unit represented by the following general formula (A-III) is a ring-opening polymer of a norbornene compound.

[0086] [ka]

[0087] In the general formula (A-II) or (A-III), m is an integer of 0 to 4, with 0 or 1 being preferred. R of formula (A-II) or (A-III) 3 ~R 6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. In the present invention, the hydrocarbon group is not particularly limited as long as it is a group consisting of carbon atoms and hydrogen atoms, and examples thereof include alkyl groups, alkenyl groups, alkynyl groups, aryl groups (aromatic hydrocarbon groups), etc. Among these, alkyl groups and aryl groups are preferred. X 2 and X 3 , Y 2 and Y 3each independently represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms substituted with a halogen atom, -(CH2)nCOOR 11 , -(CH2)nOCOR 12 , -(CH2)nNCO, -(CH2)nNO2, -(CH2)nCN, -(CH2)nCONR 13 R 14 , -(CH2)nNR 13 R 14 , -(CH2)nOZ, -(CH2)nW, or X 2 and Y 2 or X 3 and Y 3 are bonded to each other to form (-CO)2O or (-CO)2NR 15 Represents. where X 2 , X 3 , Y 2 and Y 3 R in each of the above groups 11 ~R 15 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, Z represents a hydrocarbon group or a hydrocarbon group substituted with a halogen, and W represents Si(R 16 ) p D (3-p) (R 16 represents a hydrocarbon group having 1 to 10 carbon atoms, D represents a halogen atom, -OCOR 17 -OR 17 (R 17 represents a hydrocarbon group having 1 to 10 carbon atoms. p represents an integer of 0 to 3. n represents an integer of 0 to 10, preferably 0 to 8, and more preferably 0 to 6.

[0088] R in general formula (A-II) or (A-III) 3 ~R 6 are each preferably a hydrogen atom or —CH 3 , and more preferably a hydrogen atom in terms of moisture permeability. X 2 and X 3 are each preferably a hydrogen atom, —CH 3 , or —C 2 H 5 , and more preferably a hydrogen atom in terms of moisture permeability. Y 2 and Y3 are respectively a hydrogen atom, a halogen atom (especially a chlorine atom) or -(CH2)nCOOR 11 (particularly -COOCH3) is preferred, and in terms of moisture permeability, a hydrogen atom is more preferred. The other groups are selected appropriately.

[0089] The polymer having the structural unit represented by general formula (A-II) or (A-III) may further contain at least one structural unit represented by the following general formula (AI).

[0090] [ka]

[0091] R in general formula (AI) 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms; X 1 and Y 1 each independently represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms substituted with a halogen atom, -(CH2)nCOOR 11 , -(CH2)nOCOR 12 , -(CH2)nNCO, -(CH2)nNO2, -(CH2)nCN, -(CH2)nCONR 13 R 14 , -(CH2)nNR 13 R 14 , -(CH2)nOZ, -(CH2)nW, or X 1 and Y 1 are bonded to each other to form (-CO)2O or (-CO)2NR 15 Represents. where X 1 and Y 1 R in each of the above groups 11 ~R 15 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, Z represents a hydrocarbon group or a hydrocarbon group substituted with a halogen, and W represents Si(R 16 ) p D (3-p) (R16 represents a hydrocarbon group having 1 to 10 carbon atoms, D represents a halogen atom, -OCOR 17 -OR 17 (R 17 represents a hydrocarbon group having 1 to 10 carbon atoms. p represents an integer of 0 to 3. n represents an integer of 0 to 10.

[0092] From the viewpoint of adhesion to polarizers, the cyclic polyolefin having structural units represented by general formula (A-II) or (A-III) preferably contains the structural units derived from the above-mentioned norbornene compound in an amount of 90 mass % or less, more preferably 30 to 85 mass %, even more preferably 50 to 79 mass %, and most preferably 60 to 75 mass %, based on the total mass of the cyclic polyolefin. Here, the proportion of the structural units derived from the norbornene compound represents the average value in the cyclic polyolefin.

[0093] Addition (co)polymers of norbornene compounds are described in JP-A-10-7732, JP-A-2002-504184, U.S. Patent Publication No. 2004 / 229157A1, WO 2004 / 070463, etc., the contents of which can be referenced as appropriate, and the contents thereof are incorporated herein in their entirety as part of the present specification. A polymer of a norbornene compound can be obtained by addition polymerization of norbornene compounds (for example, polycyclic unsaturated compounds of norbornene).

[0094] Further, examples of polymers of norbornene compounds include copolymers obtained by addition copolymerization of a norbornene compound with an olefin such as ethylene, propylene, or butene, a conjugated diene such as butadiene or isoprene, a non-conjugated diene such as ethylidene norbornene, or an ethylenically unsaturated compound such as acrylonitrile, acrylic acid, methacrylic acid, maleic anhydride, an acrylic acid ester, a methacrylic acid ester, maleimide, vinyl acetate, or vinyl chloride. Among these, copolymers with ethylene are preferred. Such addition (co)polymers of norbornene compounds are sold by Mitsui Chemicals, Inc. under the trade name APEL, and examples thereof include APL8008T (Tg 70°C), APL6011T (Tg 105°C), APL6013T (Tg 125°C), and APL6015T (Tg 145°C), which have different glass transition temperatures (Tg). Polyplastics also sells pellets such as TOPAS8007, TOPAS6013, and TOPAS6015. Ferrania also sells Appear3000.

[0095] The above-mentioned polymer of a norbornene compound may be commercially available, for example, under the trade names Arton, specifically Arton G, F, and RX4500, from JSR Corporation, or Zeonor ZF14, ZF16, Zeonex 250, or Zeonex 280, from Zeon Corporation.

[0096] A hydrogenated polymer of a norbornene compound can be synthesized by subjecting a norbornene compound, etc., to addition polymerization or metathesis ring-opening polymerization, followed by hydrogenation. The synthesis method is described in, for example, JP-A Nos. 1-240517, 7-196736, 60-26024, 62-19801, 2003-159767, and 2004-309979.

[0097] The molecular weight of the cycloolefin polymer used in the present invention is appropriately selected depending on the intended use, but the mass average molecular weight, calculated as polyisoprene or polystyrene, measured by gel permeation chromatography of a cyclohexane solution (or a toluene solution if the polymer is not soluble) is usually in the range of 5,000 to 500,000, preferably 8,000 to 200,000, and more preferably 10,000 to 100,000. A polymer having a molecular weight within the above range can achieve a good balance between high levels of mechanical strength and molding processability in a molded article.

[0098] (Poly(meth)acrylic resin) The poly(meth)acrylic polymer contained in the poly(meth)acrylic resin includes a polymer containing a structural unit derived from (meth)acrylic acid and / or its ester, specifically a polymer obtained by polymerizing at least one compound selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid ester, (meth)acrylamide, and (meth)acrylonitrile. The poly(meth)acrylic polymer preferably includes a homopolymer or copolymer obtained by (co)polymerizing a compound represented by the following general formula A1 as a monomer component. [ka]

[0099] In general formula A1, R a1 represents a hydroxy group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. a1 is preferably a hydroxy group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted aryloxy group, and more preferably a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 18 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 24 carbon atoms. R a2 represents a hydrogen atom, a methyl group, or an alkyl group having two or more carbon atoms. a2 is preferably a hydrogen atom or a methyl group. R in General Formula A1 a1 and R a2 A preferred combination of R a1 is a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 18 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 24 carbon atoms, and R a2 is a hydrogen atom or a methyl group.

[0100] Specific examples of the compound represented by the general formula A1 include the following. Acrylic acid compounds or methacrylic acid compounds Acrylic ester compounds Methyl acrylate, ethyl acrylate, (n- or i-)propyl acrylate, (n-, i-, sec- or t-)butyl acrylate, amyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxypentyl acrylate, cyclohexyl acrylate, allyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, benzyl acrylate, methoxybenzyl acrylate, chlorobenzyl acrylate, hydroxybenzyl acrylate, hydroxyphenethyl acrylate, dihydroxyphenethyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, phenyl acrylate, hydroxyphenyl acrylate, chlorophenyl acrylate, sulfamoylphenyl acrylate, 2-(hydroxyphenylcarbonyloxy)ethyl acrylate

[0101] Methacrylate compounds Methyl methacrylate, ethyl methacrylate, (n- or i-)propyl methacrylate, (n-, i-, sec- or t-)butyl methacrylate, amyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, chloroethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxypentyl methacrylate, cyclohexyl methacrylate, allyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, benzyl methacrylate, methoxybenzyl methacrylate, chlorobenzyl methacrylate, hydroxybenzyl methacrylate, hydroxyphenethyl methacrylate, dihydroxyphenethyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, phenyl methacrylate, hydroxyphenyl methacrylate, chlorophenyl methacrylate, sulfamoylphenyl methacrylate, 2-(hydroxyphenylcarbonyloxy)ethyl methacrylate

[0102] Acrylamide compounds Acrylamide, N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide, N-butylacrylamide, N-benzylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-tolylacrylamide, N-(hydroxyphenyl)acrylamide, N-(sulfamoylphenyl)acrylamide, N-(phenylsulfonyl)acrylamide, N-(tolylsulfonyl)acrylamide, N,N-dimethylacrylamide, N-methyl-N-phenylacrylamide, N-hydroxyethyl-N-methylacrylamide

[0103] Methacrylamide compounds Methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N-propylmethacrylamide, N-butylmethacrylamide, N-benzylmethacrylamide, N-hydroxyethylmethacrylamide, N-phenylmethacrylamide, N-tolylmethacrylamide, N-(hydroxyphenyl)methacrylamide, N-(sulfamoylphenyl)methacrylamide, N-(phenylsulfonyl)methacrylamide, N-(tolylsulfonyl)methacrylamide, N,N-dimethylmethacrylamide, N-methyl-N-phenylmethacrylamide, N-hydroxyethyl-N-methylmethacrylamide

[0104] Preferred poly(meth)acrylic polymers are homopolymers obtained by polymerizing the compound represented by the general formula A1, and two- to four-component, preferably two- or three-component copolymers obtained by polymerizing 10 to 90%, preferably 20 to 80%, in a molar ratio of the compound represented by the general formula A1 together with other compounds or further compounds represented by the general formula A1. Examples of such other compounds include substituted or unsubstituted styrene compounds and acrylonitrile. The poly(meth)acrylic polymer is preferably a homopolymer obtained by polymerizing an acrylic acid ester or methacrylic acid ester having 4 to 24 carbon atoms, a copolymer obtained by polymerizing two or more compounds represented by the above general formula A1, or a two- or three-component copolymer containing an acrylic acid ester and a methacrylic acid ester in a molar ratio of 10 to 90%.

[0105] The molecular weight of the poly(meth)acrylic polymer is selected appropriately depending on the intended use, but the weight average molecular weight, calculated as polyisoprene or polystyrene, measured by gel permeation chromatography of a cyclohexane solution (or a toluene solution if the polymer is not soluble) is usually in the range of 5,000 to 500,000, preferably 8,000 to 200,000, and more preferably 10,000 to 100,000. A polymer having a molecular weight within the above range can achieve a good balance between high levels of mechanical strength and moldability of the molded article.

[0106] (polyester resin) Examples of polyester polymers contained in the polyester resin include polymers obtained by reacting a polyol (e.g., ethylene glycol, propylene glycol, glycerin, and trimethylolpropane) with a polybasic acid (e.g., aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and dicarboxylic acids in which hydrogen atoms on these aromatic rings are substituted with methyl groups, ethyl groups, or phenyl groups), aliphatic dicarboxylic acids having 2 to 20 carbon atoms (e.g., adipic acid, sebacic acid, and dodecanedicarboxylic acid), or alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid), as well as polymers obtained by ring-opening polymerization of cyclic ester compounds such as caprolactone monomers (e.g., polycaprolactone). Furthermore, for polyester polymers, the disclosure of "Polyester" in JP 2009-096971 A can be referenced as appropriate, and the disclosure thereof is incorporated herein in its entirety as part of the present specification.

[0107] (cellulose acylate resin) The cellulose acylate contained in the cellulose acylate resin is not particularly limited, and any commonly used cellulose acylate can be used appropriately. For example, the cellulose acylates described in paragraphs 0016 to 0021 of JP-A No. 2012-215689 are preferably used, and the contents of these paragraphs are incorporated herein as is.

[0108] (Polycarbonate resin) The polycarbonate contained in the polycarbonate resin is composed of the following polyhydric phenol compound and a carbonate compound such as a bisalkyl carbonate, a bisaryl carbonate, or phosgene. Examples of polyhydric phenol compounds include hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bisphenol A, bisphenol C, bisphenol E, bisphenol F, bisphenol M, bisphenol P, bisphenol S, bisphenol Z, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(3-phenyl-4 -hydroxyphenyl)propane, 2,2-bis(3-isopropyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfide, 3,3'-dimethyl-4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl oxide, and the like. Of the above polyhydric phenol compounds, hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, and bisphenol A are preferred.

[0109] Examples of the carbonate ester compound include phosgene, diphenyl carbonate, bis(chlorophenyl) carbonate, dinaphthyl carbonate, bis(diphenyl) carbonate, dimethyl carbonate, diethyl carbonate, and dibutyl carbonate. Of the above carbonate ester compounds, phosgene, bis(diphenyl)carbonate, dimethyl carbonate, and diethyl carbonate are preferred.

[0110] In the polycarbonate, a preferred combination of monomers and polymers includes bisphenol A polycarbonate using bisphenol A as the polyhydric phenol compound and phosgene as the carbonate ester compound. As the polycarbonate, commercially available products may be used, such as Panlite (registered trademark) L-1250WP (trade name, aromatic polycarbonate resin powder, manufactured by Teijin Limited), Panlite (registered trademark) SP-1516 (trade name, manufactured by Teijin Limited), Iupizeta (registered trademark) EP-5000 (trade name, manufactured by Mitsubishi Gas Chemical Company, Inc.), Iupizeta (registered trademark) EP-4000 (trade name, manufactured by Mitsubishi Gas Chemical Company, Inc.), and Caliber 301-30 (SD Polyca 301-30) (trade name, manufactured by Sumika Styron Polycarbonate Co., Ltd.).

[0111] (Polythiourethane resin) Polythiourethane resin is a urethane bond (-NR T Any polymer having a thiourethane bond in which at least one oxygen atom in —CO—O—) is substituted with a sulfur atom may be used, and examples thereof include a polymer having a thiourethane bond in the form of —NR T -CS-O-, -NR T -CO-S- or -NR T -CS-S-, where R T represents a hydrogen atom or a substituent.

[0112] The resin used in the resin composition of the present invention preferably has a glass transition temperature (Tg) of -80 to 200°C, more preferably -30 to 180°C. When the resin composition contains a resin exhibiting a Tg within the above range, an optical filter with appropriate softness and hardness can be produced. The glass transition temperature of the resin can be appropriately adjusted by the resin composition (type or content of constituent components), etc. The glass transition temperature of the resin can be measured using a differential scanning calorimeter (DSC) according to the method described in "Guide to Instrumental Analysis" (publisher: Kagaku Dojin Co., Ltd.).

[0113] The resin composition of the present invention preferably contains 50% by mass or more of a binder resin in the total solid content (specifically, in the components excluding the organic solvent described below) from the viewpoint of the sharpness of the absorption waveform and light resistance, more preferably 70% by mass or more, and particularly preferably 90% by mass or more. The resin composition may contain two or more binder resins, and binder resins with different composition ratios and / or molecular weights may be used in combination, in which case the total content of each binder resin falls within the above range.

[0114] <Additives> The resin composition of the present invention may contain additives as long as they do not impair the effects of the present invention. For example, if necessary, additives that are commonly incorporated into plastic films may be contained. Examples of such additives include antioxidants, heat stabilizers, light resistance stabilizers, UV absorbers, antistatic agents, lubricants, plasticizers, and fillers, and the content thereof may be selected within a range that does not impair the object of the present invention. Examples of additives include known plasticizers, organic acids, polymers, retardation adjusters, UV absorbers, antioxidants, and matting agents. For details, please refer to paragraphs

[0062] to

[0097] of JP 2012-155287 A, the contents of which are incorporated herein by reference. Examples of additives include release promoters, organic acids, and polycarboxylic acid derivatives. For these details, please refer to the descriptions in paragraphs

[0212] to

[0219] of WO 2015 / 005398, the contents of which are incorporated herein by reference. Further examples of additives include radical scavengers and deterioration inhibitors, which will be described later. The content of the additives (when the resin composition contains two or more types of additives, the total content of these additives) is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 5 to 30 parts by mass, per 100 parts by mass of the binder resin.

[0115] (antioxidant) One preferred additive is an antioxidant. For details of antioxidants, please refer to paragraphs

[0143] to

[0165] of WO 2015 / 005398, the contents of which are incorporated herein by reference.

[0116] (radical scavenger) A preferred additive is a radical scavenger. For details of the radical scavenger, please refer to paragraphs

[0166] to

[0199] of WO 2015 / 005398, the contents of which are incorporated herein by reference.

[0117] (anti-deterioration agent) One preferred additive is an anti-degradant. For details of the anti-degradant, please refer to paragraphs

[0205] and

[0206] of WO 2015 / 005398, the contents of which are incorporated herein by reference.

[0118] (ultraviolet absorber) In the present invention, an ultraviolet absorber may be added to the optical filter from the viewpoint of preventing deterioration. As the ultraviolet absorber, one that has excellent absorption ability for ultraviolet light with a wavelength of 370 nm or less and has little absorption of visible light with a wavelength of 400 nm or more is preferably used from the viewpoint of good liquid crystal display properties. Specific examples of ultraviolet absorbers that are preferably used in the present invention include hindered phenol compounds, hydroxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, and nickel complex salt compounds. Examples of hindered phenolic compounds include 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and tris-(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate. Examples of benzotriazole compounds include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2,2-methylenebis(4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol), (2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylanilino)-1,3,5-triazine, triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 1,3,5-trimethyl-2 ,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 2(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, (2(2'-hydroxy-3',5'-di-tert-amylphenyl)-5-chlorobenzotriazole, 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol, and the like.

[0119] The resin composition of the present invention may contain various additives. However, when used as a material for forming an optical filter, it may be in an embodiment in which it does not contain an antifading agent. In the present invention, "not containing an antifading agent" refers to a case in which the antifading agent is contained in an amount less than the amount necessary to prevent fading of the optical filter (the dye contained in the optical filter), for example, less than 1% by mass, preferably less than 0.5% by mass, based on 100% by mass of the total solids content. The antifading agent is not particularly limited, and examples include commonly used antifading agents, such as the antioxidants described in paragraphs

[0143] to

[0165] of WO 2015 / 005398 A1, the radical scavengers described in paragraphs

[0166] to

[0199] of WO 2015 / 005398 A1, and the antidegradants described in paragraphs

[0205] to

[0206] of WO 2015 / 005398 A1. Furthermore, when the resin composition of the present invention is used as a material for forming an optical filter, it can be configured not to contain the copper compound described in Patent Document 2.

[0120] <Solvent> The resin composition of the present invention may also contain a solvent. In particular, the resin composition of the present invention for forming the coated and dried product described below preferably contains a solvent having a boiling point of 200°C or less, and the squarylium compound and resin are dissolved in the solvent. Here, "dissolved squarylium compound and resin" includes not only an embodiment in which the squarylium compound and resin are completely dissolved in the solvent, but also an embodiment in which a portion of the squarylium compound and resin are not dissolved, for example, an embodiment in which 0.5% by mass or less of the squarylium compound and resin are undissolved and exist in a solid state, relative to a total of 100% by mass of the squarylium compound and resin. The boiling point of the solvent can be appropriately determined depending on the coating and drying conditions described below, but is preferably 180°C or lower, more preferably 160°C or lower, from the viewpoint of avoiding excessive heating during drying and saving energy. On the other hand, the lower limit is not particularly limited and can be, for example, 60°C or higher. In the present invention, the boiling point of the solvent is the standard boiling point or ordinary boiling point, and means the boiling point under a pressure of 101,325 Pa (normal pressure). The organic solvent and its content are the same as those in the "Method for producing an optical filter" below.

[0121] <Preparation of Resin Composition> The resin composition of the present invention can be prepared by a conventional method. When the resin composition of the present invention is a simple mixture of a squarylium compound and a resin, it can be prepared by dry mixing the squarylium compound and the resin by a conventional method. When the resin composition of the present invention is a liquid composition, it can be prepared by wet mixing the squarylium compound, resin, and solvent by a standard method. When the resin composition of the present invention is a coated and dried product, it can be prepared by coating and drying the liquid composition on a substrate. The substrate is not particularly limited, and examples thereof include a resin substrate, a glass substrate, a metal substrate, a vapor-deposited film, and the surface of a member on which an optical filter (described later) is disposed. The method for applying the liquid composition is not particularly limited, and examples thereof include spraying, dipping, roller coating, flow coating (e.g., the solution casting film-forming method described later), flow coating, bar coating, blade coating, and spin coating. The coating conditions are not particularly limited, and are appropriately set taking into consideration the coating amount and viscosity of the liquid composition, as well as the shape and dimensions of the coated and dried product. The drying method and conditions are not particularly limited, and are appropriately set, as long as the solvent in the liquid composition can be removed to the above-mentioned residual amount or less. For example, heating methods include heat drying and air drying, with heat drying being preferred. The heating temperature is not particularly limited, and can be a temperature above the boiling point of the solvent under the ambient pressure during drying, for example, 50 to 200°C under normal pressure. When the resin composition of the present invention is a melt mixture, it can be prepared by mixing the squarylium compound and the resin (including a simple mixture) while heating to melt the resin, and then cooling and solidifying. The melt mixing temperature is not particularly limited as long as it is equal to or higher than the temperature at which the resin melts, and can be appropriately determined depending on the type of resin, melting point, glass transition temperature, etc. For example, it can be 180°C or higher, and preferably 200°C or higher. The upper limit can be, for example, 400°C or lower, and preferably 350°C or lower. The melt mixing method and conditions are appropriately determined, and are usually performed using various mixers. When preparing the coated dried product and molten mixture, preparation conditions, such as the amount of coating and cooling method, can be determined so that the shape and dimensions will be appropriate for the application. The prepared resin composition can be adjusted to a shape and further to a size according to the intended use, etc., by a conventional method, such as a molding method, a size adjustment method, etc. The molten mixture can also be subjected to the later-described heat melt molding method in which melt solidification and molding are carried out.

[0122] [Optical filter] The resin composition of the present invention is suitable as a material for forming an optical filter by appropriately molding, etc. Optical filters are usually molded into a flat membrane or film shape, but in the present invention, the optical filter may also be molded into various shapes such as a curved membrane or film shape corresponding to the surface shape of a member on which the optical filter is to be disposed, or a powder shape, a sphere shape, a crushed particle shape, a continuous aggregate shape, a fiber shape, a tube shape, a hollow fiber shape, a granular shape, a porous shape, etc. The optical filter of the present invention is formed from the resin composition, the coated and dried product, or the melt-kneaded product of the present invention and has a predetermined shape. The optical filter of the present invention is preferably a film-shaped product obtained by molding the resin composition, the coated and dried product, or the melt-kneaded product of the present invention into a membrane or film, and more preferably a membrane-shaped or film-shaped molded product of the resin composition of the present invention. The content of each component (solid content excluding organic solvent) in the optical filter is the same as the content in the resin composition of the present invention (solid content).

[0123] The optical filter of the present invention can be suitably used as a light absorption filter (film) that highly absorbs (blocks) light of a specific target wavelength, such as light of an unwanted wavelength, from incident light. Furthermore, the optical filter of the present invention exhibits the above-mentioned excellent properties, can highly absorb (block) near-infrared light in the above-mentioned wavelength range, and also has excellent oblique incidence characteristics. Therefore, in addition to being a light absorption filter, the optical filter of the present invention can also be suitably used as a near-infrared cut filter that performs luminosity correction for solid-state imaging devices that use silicon photodiodes that sense infrared light as their light receiving section. When the optical filter of the present invention is used as a near-infrared cut filter, it can be used in the usual manner (method of use, etc.). For example, the description of Japanese Patent No. 6605039 is useful, and the contents of this specification are incorporated herein by reference.

[0124] <Method of manufacturing optical filters> A method for producing an optical filter will be described below. The optical filter is not particularly limited except that the resin composition, the coated and dried product, or the melt-kneaded product of the present invention is used, and can be appropriately produced by a conventional production method. For example, the method described above for preparing the resin composition can be applied.

[0125] (Solution casting film forming method) When the optical filter of the present invention is in the form of a membrane or film, it can be produced using the above-mentioned dried coating or molten mixture, but one of the preferred embodiments is to produce it by a solution casting film-forming method. In the solution casting film-forming method, a film is produced using a solution (dope, a "liquid composition" as one form of the resin composition of the present invention) in which at least a squarylium compound and a binder resin are dissolved in an organic solvent.

[0126] The organic solvent is not particularly limited as long as it can dissolve the squarylium compound and the binder resin. For example, a solvent selected from aliphatic hydrocarbon solvents having 6 to 12 carbon atoms, aromatic hydrocarbon solvents having 6 to 20 carbon atoms, alcohol solvents having 1 to 4 carbon atoms, ether solvents having 3 to 12 carbon atoms, ketone solvents having 3 to 12 carbon atoms, ester solvents having 3 to 12 carbon atoms, and halogenated hydrocarbon solvents having 1 to 6 carbon atoms, as well as mixed solvents thereof, can be used. Preferred examples of mixed solvents include mixed solvents of aliphatic hydrocarbon solvents or ketone solvents with aromatic hydrocarbon solvents. Aliphatic hydrocarbon solvents, ether solvents, ketone solvents, and ester solvents may have a cyclic structure. Compounds having two or more of the functional groups (i.e., -O-, -CO-, and COO-) of the ether solvents, ketone solvents, and ester solvents (e.g., alkylene glycol monoalkyl ethers, alkylene glycol dialkyl ethers, alkylene glycol monoalkyl ether acetates, and alkylene glycol dialkyl ether acetates) can also be used as the organic solvent. The organic solvent may also have other functional groups, such as alcoholic hydroxyl groups. In the case of an organic solvent having two or more types of functional groups, the number of carbon atoms thereof is preferably within the above-mentioned preferred carbon atom number range for the solvent having any of the functional groups. The organic solvent should have a boiling point of 200° C. or less, so that drying at an excessively high temperature after coating can be avoided. The preferred range of the boiling point is as described above.

[0127] The content of the binder resin in the solution is preferably adjusted to 1 to 80% by mass, and more preferably 10 to 75% by mass. The organic solvent (main solvent) may contain any of the above-mentioned additives. The total content of all solids in the solution is the sum of the contents of the squarylium compound, binder resin, and additives, and is, for example, preferably 1 to 80 mass%, more preferably 5 to 75 mass%, and even more preferably 10 to 65 mass%.

[0128] For drying methods in solution casting film formation methods, reference can be made to the specifications of U.S. Patent Nos. 2,336,310, 2,367,603, 2,492,078, 2,492,977, 2,492,978, 2,607,704, 2,739,069, and 2,739,070, the specifications of British Patent Nos. 640731 and 736892, and Japanese Patent Publication Nos. 45-4554, 49-5614, and Japanese Patent Laid-Open Nos. 60-176834, 60-203430, and 62-115035. Drying on a band can be carried out by blowing an inert gas such as air or nitrogen.

[0129] The dope is preferably cast onto a band and the solvent is evaporated to form a film. The concentration of the dope before casting is preferably adjusted so that the solid content is in the range of 10 to 40 mass %. The surface of the band is preferably mirror-finished. The prepared solution (dope) can be cast into two or more layers to form a film.

[0130] When multiple dopes, such as cycloolefin resin solutions, are cast to produce a film having two or more layers, the dopes may be cast from multiple casting nozzles spaced apart in the direction of travel of the support to produce a laminated film. For example, methods described in JP-A-61-158414, JP-A-1-122419, and JP-A-11-198285 can be used. Alternatively, a film can be produced by casting a dope from two casting nozzles. For example, methods described in JP-B-60-27562, JP-A-61-94724, JP-A-61-947245, JP-A-61-104813, JP-A-61-158413, and JP-A-6-134933 can be used. Furthermore, a resin film casting method can be used, as described in Japanese Patent Application Laid-Open No. 56-162617, in which a flow of a high viscosity resin solution is enveloped in a low viscosity resin solution, and the high and low viscosity resin solutions are extruded simultaneously.

[0131] Alternatively, a film can be produced by using two casting nozzles, peeling off the film cast on the support through the first casting nozzle, and casting the second film on the side that had been in contact with the support surface, as described in, for example, JP-B-44-20235.

[0132] The solution to be cast may be the same solution, or two or more different solutions may be used. To impart functions to multiple layers, solutions according to the functions may be extruded from the respective casting nozzles. Furthermore, the solution casting film formation can also be performed by simultaneously casting other functional layers (e.g., adhesive layer, dye layer, antistatic layer, antihalation layer, UV absorbing layer, polarizing layer, etc.).

[0133] The compound (dye) represented by the general formula (1) can be added to the above solution by, for example, mixing it in an organic solvent together with a binder resin when preparing a dope.

[0134] (Drying process) The process from casting the dope to post-drying may be carried out in an air atmosphere or an inert gas atmosphere such as nitrogen gas. The winding machine used for producing the optical filter of the present invention may be a commonly used one, and winding may be carried out by a winding method such as a constant tension method, a constant torque method, a taper tension method, or a program tension control method with a constant internal stress. The drying conditions may be, for example, the drying conditions used for producing a coated and dried product.

[0135] (Stretching process) The optical filter may be stretched to impart a desired retardation to the optical filter. The optical filter may be stretched in either the width direction or the length direction. Methods of stretching in the width direction are described in, for example, JP-A Nos. 62-115035, 4-152125, 4-284211, 4-298310, and 11-48271.

[0136] The film (optical filter before stretching) is stretched under heating conditions. The film can be stretched during the drying process, which is particularly effective when a solvent remains. In the case of longitudinal stretching, for example, the film can be stretched by adjusting the speed of the film transport roller so that the film winding speed is faster than the film peeling speed. In the case of widthwise stretching, the film can also be stretched by transporting the film while holding its width with a tenter and gradually widening the tenter width. After drying, the film can also be stretched using a stretching machine (preferably uniaxial stretching using a long stretching machine).

[0137] The molding method for optical filters is not particularly limited, and can be the same as the method described above. Furthermore, both hot melt molding and solution casting can be used. Hot melt molding can be further classified into extrusion molding, press molding, inflation molding, injection molding, blow molding, and stretch molding. Among these methods, extrusion molding, inflation molding, and press molding are preferred, with extrusion molding being the most preferred, in order to obtain films with excellent mechanical strength and surface precision. Molding conditions are appropriately selected depending on the intended use and molding method. When using hot melt molding, the cylinder temperature is typically set within the range of 150 to 400°C, preferably 200 to 350°C, and more preferably 230 to 330°C. An excessively low polymer temperature can result in poor flowability, causing sink marks and distortion in the film. An excessively high polymer temperature can result in voids or silver streaks due to thermal decomposition of the polymer, or molding defects such as yellowing of the film.

[0138] (Physical properties or characteristics of optical filters) The preferred physical properties or characteristics of the optical filter of the present invention will now be described. As described above, the optical filter of the present invention has little variation in the state of existence of the squarylium compound and is excellent in surface condition, as specifically shown in the evaluation of surface condition in the examples described later.

[0139] The thickness of the optical filter is usually in the range of 0.1 to 300 μm, preferably 0.2 to 200 μm, and more preferably 0.3 to 100 μm, taking into consideration ease of handling during lamination and improved productivity due to a shortened drying time.

[0140] The optical filter preferably has a surface wetting tension of 40 mN / m or more, more preferably 50 mN / m or more, and even more preferably 55 mN / m or more. When the surface wetting tension is within the above range, the adhesive strength between the optical filter and the polarizer is improved. To adjust the surface wetting tension, for example, corona discharge treatment, ozone spraying, ultraviolet irradiation, flame treatment, chemical treatment, or other known surface treatments can be performed.

[0141] The retardation of the optical filter of the present invention will now be described. The in-plane retardation value Ro at 589 nm of the optical filter of the present invention is preferably 0 to 20 nm, more preferably 0 to 10 nm. The retardation value Rth in the thickness direction is preferably -20 to 50 nm, more preferably -10 to 20 nm. Generally, retardation can be controlled by the retardation of the film before stretching, the stretching ratio, the stretching temperature, and the thickness of the stretch-oriented film. When the thickness of the film before stretching is constant, the absolute value of retardation tends to increase as the stretching ratio increases, so a stretch-oriented film with a desired retardation can be obtained by changing the stretching ratio.

[0142] When an optical filter is stretched, the thickness of the optical filter before stretching is preferably about 50 to 500 μm, and the smaller the thickness unevenness, the better, within ±8% over the entire surface, preferably within ±6%, and more preferably within ±4%. The stretching ratio is preferably 1.1 to 10 times, more preferably 1.3 to 8 times, and it is sufficient to obtain a desired retardation within this range. The optical filter thus obtained can have a desired retardation value due to molecular orientation caused by stretching.

[0143] The smaller the variation in retardation, the better. The optical filter of the present invention has a small variation in retardation at a wavelength of 589 nm, both in the in-plane and thickness direction, usually within ±50 nm, preferably ±30 nm or less, and more preferably ±20 nm or less.

[0144] The in-plane and thickness-direction variations in retardation and thickness unevenness of the optical filter can be reduced by using a film before stretching that has small variations in retardation and by applying uniform stress to the film during stretching. To achieve this, it is desirable to stretch the film under a uniform temperature distribution, preferably in an environment where the temperature is controlled within ±5°C, more preferably within ±2°C, and particularly preferably within ±0.5°C.

[0145] [Image display device] Examples of the image display device of the present invention include a liquid crystal display device and an organic electroluminescence display device. The image display device of the present invention will be described below taking as an example a liquid crystal display device (also referred to as "the liquid crystal display device of the present invention"), which is a preferred embodiment. The liquid crystal display device of the present invention is characterized by including at least one optical filter of the present invention. The optical filter of the present invention may be used as a polarizing plate protective film and / or a pressure-sensitive adhesive layer as described below, or may be included in a backlight unit used in the liquid crystal display device.

[0146] The liquid crystal display device preferably includes an optical filter, a polarizing plate including a polarizer and a polarizing plate protective film, a pressure-sensitive adhesive layer, and a liquid crystal cell, and the polarizing plate is preferably attached to the liquid crystal cell via the pressure-sensitive adhesive layer. In this liquid crystal display device, the optical filter may also serve as the polarizing plate protective film or the pressure-sensitive adhesive layer. That is, the liquid crystal display device can be divided into a case where it includes a polarizing plate including a polarizer and an optical filter (polarizing plate protective film), a pressure-sensitive adhesive layer, and a liquid crystal cell, and a case where it includes a polarizing plate including a polarizer and a polarizing plate protective film, an optical filter (pressure-sensitive adhesive layer), and a liquid crystal cell.

[0147] FIG. 1 is a schematic diagram showing an example of a liquid crystal display device of the present invention. In FIG. 1, the liquid crystal display device 10 comprises a liquid crystal cell having a liquid crystal layer 5 and a liquid crystal cell upper electrode substrate 3 and a liquid crystal cell lower electrode substrate 6 arranged above and below the liquid crystal layer 5, and an upper polarizer 1 and a lower polarizer 8 arranged on either side of the liquid crystal cell (the directions of their respective absorption axes are indicated by arrows labeled 2 and 9). A color filter layer may be laminated on the liquid crystal cell upper electrode substrate 3 or the liquid crystal cell lower electrode substrate 6 (the respective alignment control is indicated by arrows labeled 4 and 7). A backlight unit B is arranged on the back of the liquid crystal display device 10. The light source of the backlight unit B is not particularly limited. For example, a light-emitting device using a white LED can be used.

[0148] The upper polarizing plate 1 and the lower polarizing plate 8 each have a structure in which two polarizing plate protective films are laminated to sandwich a polarizer, and it is preferable that in the liquid crystal display device 10 of the present invention, at least one of the polarizing plates is a polarizing plate that includes the optical filter (not shown) of the present invention. In the liquid crystal display device 10 of the present invention, the liquid crystal cell and the polarizing plate (upper polarizing plate 1 and / or lower polarizing plate 8) may be bonded together via an adhesive layer (not shown). In this case, the optical filter of the present invention may also serve as the adhesive layer. The liquid crystal display device 10 may be of a direct-view type, a projection type, or a light modulation type. The present invention is effective for active matrix liquid crystal display devices using three-terminal or two-terminal semiconductor elements such as TFTs or MIMs. Of course, the present invention is also effective for passive matrix liquid crystal display devices, such as the STN mode, which is known as time-division driving. When the optical filter of the present invention is included in the backlight unit B, the polarizing plate of the liquid crystal display device may be a normal polarizing plate (a polarizing plate not including the optical filter of the present invention) or a polarizing plate including the optical filter of the present invention. In addition, the pressure-sensitive adhesive layer may be a normal pressure-sensitive adhesive layer (not including the optical filter of the present invention) or a pressure-sensitive adhesive layer including the optical filter of the present invention.

[0149] The IPS mode liquid crystal display device described in paragraphs 128 to 136 of JP-A No. 2010-102296 is preferable as the liquid crystal display device of the present invention.

[0150] <Polarizing plate> The polarizing plate used in the present invention includes a polarizer and at least one polarizing plate protective film. The polarizing plate used in the present invention preferably has a polarizer and polarizing plate protective films on both sides of the polarizer, and preferably includes the optical filter of the present invention as a polarizing plate protective film on at least one side. The polarizer may have a conventional polarizing plate protective film on the side opposite to the side having the optical filter (polarizing plate protective film) of the present invention. The thickness of the polarizing plate protective film used in the present invention is 5 μm or more and 120 μm or less, and more preferably 10 μm or more and 100 μm or less. A thinner film is preferable because it is less likely to cause display unevenness after aging at high temperature and high humidity when incorporated into a liquid crystal display device. On the other hand, if the film is too thin, it becomes difficult to transport stably during film production and polarizing plate fabrication. It is preferable that the thickness of the optical filter constituting the polarizing plate protective film satisfies the above range.

[0151] -Shape, composition- The shape of the polarizing plate used in the present invention includes not only polarizing plates in the form of film pieces cut into a size that can be directly incorporated into a liquid crystal display device, but also polarizing plates produced in a long form by continuous production and wound up into a roll (for example, a roll length of 2500 m or more or 3900 m or more). For use in large-screen liquid crystal displays, the width of the polarizing plate is preferably 1470 mm or more.

[0152] The polarizing plate used in the present invention is composed of a polarizer and at least one polarizing plate protective film, and it is also preferable that a separate film be further laminated on one surface of the polarizing plate. Separation film is used to protect the polarizing plate during shipping, product inspection, etc. Separation film is used to cover the adhesive layer that is attached to the liquid crystal plate, and is used on the side where the polarizing plate is attached to the liquid crystal plate.

[0153] (polarizer) The polarizer used in the polarizing plate of the present invention will be described below. The polarizer that can be used in the polarizing plate used in the present invention is preferably composed of polyvinyl alcohol (PVA) and dichroic molecules, but as described in JP-A-11-248937, a polyvinylene-based polarizer can also be used, which is produced by dehydrating and dechlorinating PVA or polyvinyl chloride to produce a polyene structure and then oriented this structure.

[0154] -Polarizer film thickness- The thickness of the polarizer film before stretching is not particularly limited, but is preferably 1 μm to 1 mm, particularly preferably 5 to 200 μm, from the viewpoints of film holding stability and stretching uniformity. Alternatively, as described in JP-A-2002-236212, a thin PVA film may be used that generates a stress of 10 N or less when stretched 4 to 6 times in water.

[0155] -Polarizer manufacturing method- The method for producing a polarizer is not particularly limited, but it is preferable to form a film from the PVA and then introduce dichroic molecules to form a polarizer. The PVA film can be produced by referring to the methods described in

[0213] to

[0237] of JP 2007-86748 A, Japanese Patent No. 3342516, JP 09-328593 A, JP 2001-302817 A, JP 2002-144401 A, etc.

[0156] (Lamination method of polarizer and polarizing plate protective film) The polarizing plate used in the present invention is produced by adhering (laminating) at least one polarizing plate protective film (preferably the optical filter of the present invention) to at least one surface of the above polarizer. It is preferable to prepare the polarizer by alkali-treating a polarizing plate protective film, immersing a polyvinyl alcohol film in an iodine solution and stretching it, and laminating the film on both sides of the polarizer using an aqueous solution of fully saponified polyvinyl alcohol. Examples of adhesives used to attach the treated surface of the polarizing plate protective film to the polarizer include polyvinyl alcohol-based adhesives such as polyvinyl alcohol and polyvinyl butyral, and vinyl latexes such as butyl acrylate.

[0157] The polarizing plate protective film of the polarizing plate used in the present invention is preferably attached to the polarizer so that the transmission axis of the polarizer and the slow axis of the polarizing plate protective film are substantially parallel, perpendicular or at 45°. The slow axis can be measured by various known methods, for example, using a birefringence meter (KOBRADH, manufactured by Oji Scientific Instruments). Here, "substantially parallel" means that the direction of the principal refractive index nx of the polarizing plate protective film and the direction of the transmission axis of the polarizing plate intersect at an angle of ±5° or less, preferably at an angle of ±1° or less, and more preferably at an angle of ±0.5° or less. If the angle of intersection is within 1°, the polarization performance under crossed Nicol conditions of the polarizing plate is less likely to decrease and light leakage is less likely to occur, which is preferable. The direction of the principal refractive index nx and the direction of the transmission axis being orthogonal or 45° to each other means that the angle at which the direction of the principal refractive index nx and the direction of the transmission axis intersect is within a range of ±5° from the exact angle related to orthogonality and 45°, and the error from the exact angle is preferably within a range of ±1°, and more preferably within a range of ±0.5°.

[0158] (Functionalization of polarizing plates) The polarizing plate used in the present invention is also preferably used as a functionalized polarizing plate in combination with an optical film having a functional layer such as an antireflection film for improving the visibility of the display, a brightness-enhancing film, a hard coat layer, a forward scattering layer, an antiglare (anti-glare) layer, an antifouling layer, or an antistatic layer. Antireflection films, brightness-enhancing films, other functional optical films, hard coat layers, forward scattering layers, and antiglare layers for functionalization are described in

[0257] to

[0276] of JP-A No. 2007-86748, and functionalized polarizing plates can be produced based on these descriptions.

[0159] (Adhesive layer) In the liquid crystal display device of the present invention, the polarizing plate is preferably attached to the liquid crystal cell via a pressure-sensitive adhesive layer. The optical filter of the present invention may also serve as the pressure-sensitive adhesive layer. When the optical filter of the present invention does not also serve as the pressure-sensitive adhesive layer, a conventional pressure-sensitive adhesive layer can be used as the pressure-sensitive adhesive layer. The adhesive layer is not particularly limited as long as it can bond the polarizing plate and the liquid crystal cell together, but for example, acrylic, urethane, polyisobutylene, etc. are preferred. When the optical filter of the present invention also serves as an adhesive layer, the adhesive layer contains the above-mentioned dye and binder, and further contains a crosslinking agent, a coupling agent, etc. to impart adhesiveness. When the optical filter also serves as the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer preferably contains the above-mentioned binder in an amount of 90 to 100% by mass, more preferably 95 to 100% by mass. The content of the dye is as described above. The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 1 to 50 μm, and more preferably 3 to 30 μm, for example.

[0160] (liquid crystal cell) The liquid crystal cell is not particularly limited, and a conventional one can be used.

[0161] [Solid-state imaging device] The solid-state imaging device of the present invention includes the optical filter of the present invention described above. The configuration of the solid-state imaging device of the present invention is not particularly limited as long as it includes the optical filter of the present invention and functions as a solid-state imaging device. The solid-state imaging device of the present invention includes the optical filter (color filter) of the present invention, which has excellent weather resistance and contrast, and therefore has excellent image color tone and color reproducibility over long-term use.

[0162] The configuration of the solid-state imaging device is not particularly limited as long as it has the color filter of the present invention and functions as a solid-state imaging device. For example, a configuration can be mentioned in which a support has a plurality of photodiodes and light-receiving elements made of polysilicon or the like that constitute the light-receiving area of ​​a solid-state imaging device (such as a CCD image sensor or a CMOS image sensor) on the support, and the color filter of the present invention is provided on the side of the support where the light-receiving elements are formed (for example, a portion other than the light-receiving portion or a color-adjusting pixel portion) or on the opposite side of this formation surface. [Example]

[0163] The present invention will be explained in more detail below with reference to examples. The materials, reagents, amounts and proportions of substances, procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples. In the present invention, "room temperature" means 25°C.

[0164] [Example A] Synthesis and evaluation of squarylium compounds [Synthesis Example 1] Synthesis of Compound B-12

[0165] [ka]

[0166] 0.91 g of 4-butylaniline, 1.00 g of 3-bromonitrobenzene, 1.85 g of potassium carbonate, and 30 mL of isopropanol were mixed and stirred at room temperature for 1 hour while bubbling with nitrogen. Next, 0.16 g of 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (xPhos) and 0.061 g of tris(dibenzylideneacetone)dipalladium (Pd2bda3) were added, followed by heating and stirring at 110 °C for 8 hours. After the reaction was complete, the reaction mixture was returned to room temperature, ice-cooled, and 30 mL of water containing 2.15 g of ammonium chloride was slowly added dropwise. The mixture was stirred for an additional 1 hour. The resulting crystals were filtered, and the filtrate (crystals) was purified by silica gel column chromatography to yield 0.65 g (54%) of Intermediate 1.

[0167] 4.5 g of intermediate 1 and 40 mL of dimethylacetamide were added, and 0.7 g of sodium hydride was slowly added while stirring under ice cooling, followed by stirring for 30 minutes. Subsequently, 4.25 g of 2-ethylhexyl bromide was added dropwise, followed by heating and stirring at room temperature for 6 hours and then at an internal temperature of 45°C for 6 hours. After the reaction was completed, the reaction mixture was cooled and then 100 mL of water was added dropwise. Subsequently, 100 mL of ethyl acetate and 100 mL of hexane were added to extract the organic layer. The organic layer was washed with water and saturated brine, and the resulting organic layer was dried over magnesium sulfate, concentrated, and then purified by silica gel column chromatography (hexane / ethyl acetate = 4 / 1) to obtain 2.0 g (31%) of intermediate 2.

[0168] 2.0 g of intermediate 2 and 20 mL of tetrahydrofuran were added and stirred, and then 1.0 g of palladium hydroxide was added. The atmosphere in the flask was then thoroughly purged with hydrogen gas, and the reaction was carried out at room temperature for 5 hours. After the reaction was completed, the reaction mixture was filtered through Celite, and the resulting filtrate was concentrated and then purified by silica gel column chromatography (hexane / ethyl acetate = 4 / 1), yielding 1.8 g (61%) of intermediate 3.

[0169] 1.1 g of intermediate 3 and 15 mL of dimethylacetamide were added, followed by 0.42 g of dimethylaminopyridine and 0.72 g of ferrocenecarboxylic acid, and the mixture was stirred at room temperature for 30 minutes. Subsequently, 0.66 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride was added to the resulting mixture, and the mixture was stirred at room temperature for 24 hours. After the reaction was completed, 50 mL of hexane, ethyl acetate, and 100 mL of 1N hydrochloric acid were added to the reaction mixture, and the organic layer was extracted. The organic layer was washed with water and saturated brine, dried over magnesium sulfate, concentrated, and then purified by silica gel column chromatography (hexane / ethyl acetate = 4 / 1) to obtain 1.8 g (88%) of intermediate 4.

[0170] In a flask equipped with a Dean-Stark tube, 0.80 g of intermediate 4, 0.08 g of squaric acid, 10 mL of toluene, and 10 mL of n-butanol were added, mixed, and heated under reflux for 4 hours. After the reaction was completed, the reaction mixture was cooled to 0°C, and the resulting crystals were filtered. The filtrate (crystals) was washed with methanol. 10 mL of methanol was added to the resulting crude crystals, and the mixture was heated under reflux for 1 hour. The resulting crystals were filtered, and the filtrate (crystals) was washed with methanol. In this way, 0.69 g (80%) of squarylium compound B-12 was obtained.

[0171] The identification of the obtained squarylium compound B-12 was confirmed by nuclear magnetic resonance spectroscopy ( 1 H-NMR). 1 H-NMR(CDCl3):δ 11.77~11.33(m, 2H), 8.50~8.22(m, 4H), 7.28~7.26(m, 4H), 7.15~7.13(m, 4 H), 6.36~6.33(m, 2H), 5.32~5.20(m, 4H), 4.44~4.34(m, 4H), 4.23~4.15(m, 1 0H), 3.84~3.74(m, 4H), 2.69~2.65(m, 4H), 1.85~1.80(m, 2H), 1.69~1.62(m, 4H), 1.51~1.36(m, 12H), 1.24~1.22(m, 8H), 0.97(t, 6H), 0.87~0.83(m, 12H)

[0172] [Test Example 1] Measurement of maximum absorption wavelength of squarylium compounds The obtained squarylium compound B-12 was dissolved in chloroform (concentration 1 × 10 -6 The maximum absorption wavelength λmax of squarylium compound B-12 was measured using a UV-1800PC spectrophotometer (Shimadzu Corporation) with a cell having a light path length of 10 mm and a concentration of 100 mol / L. The measurement results of the maximum absorption wavelength λmax of compound B-12 are shown in Table 1 below.

[0173] [Test Example 2] Evaluation of solubility of squarylium compounds The solubility of the obtained squarylium compound B-12 in a mixed solvent of toluene and cyclohexanone (toluene / cyclohexanone = 90 / 10 (vol%)) was confirmed. Specifically, the amount (mass%) of squarylium compound B-12 dissolved in 100 parts by mass of the mixed solvent of toluene and cyclohexanone was measured. The obtained dissolved amount was applied to the following criteria to evaluate the solubility. - Evaluation criteria for solubility - A: 0.1% by mass or more B: 0.01% by mass or more and less than 0.1% by mass C: less than 0.01% by mass

[0174] According to the above-mentioned [Synthesis Example 1], the squarylium compounds shown in the following Table 1 and the following comparative compounds C-1 to C-6 were each synthesized. Specific methods for synthesizing compounds A-19, A-28 and A-4 are shown below.

[0175] [Synthesis Example 2] Synthesis of Compound A-19 Compound A-19 was synthesized according to the following scheme.

[0176] [ka]

[0177] 2.1 g of Intermediate 3 obtained in [Synthesis Example 1] above was added to 13 mL of dimethylacetamide and stirred under ice cooling. Subsequently, 0.92 g of 2,2-dimethylbutyryl chloride was added and slowly added dropwise. After the addition was complete, the mixture was returned to room temperature and stirred at room temperature for 4 hours. After the reaction was completed, the mixture was ice-cooled again, and 40 mL of water was added dropwise. Further, 5% aqueous NaOH solution was added until the reaction solution reached pH 8. Then, 60 mL of ethyl acetate was added to extract the organic layer. The organic layer was washed with water and saturated brine, and the resulting organic layer was dried over magnesium sulfate and concentrated. After purification by silica gel column chromatography (hexane / ethyl acetate = 8 / 1), 2.4 g (86%) of Intermediate 5 was obtained.

[0178] In a flask equipped with a Dean-Stark tube, 2.2 g of intermediate 5, 0.42 g of squaric acid, 10 mL of toluene, and 10 mL of n-butanol were added, mixed, and heated under reflux for 10 hours. After the reaction was completed, the reaction mixture was cooled to room temperature, and then 30 mL of methanol was added and stirred at room temperature for 2 hours. The resulting crystals were filtered, and the filtrate (crystals) was washed with methanol. In this way, 2.0 g (85%) of squarylium compound A-19 was obtained.

[0179] The identification of the obtained squarylium compound A-19 was confirmed by nuclear magnetic resonance spectroscopy ( 1 H-NMR). 1 H-NMR(CDCl3):δ 11.37~11.05(m, 2H), 8.48~8.41(m, 4H), 7.26~7.24(d, 4H), 7.11~7.09(d, 4H), 6.26~6.24(d, 2H), 3.76~3.74(m, 4H), 2.67~2. 63(m, 4H), 1.83~1.74(m, 6H), 1.67~1.60(m, 4H), 1.41~1.33(m, 24H), 1.25~1.21(m, 8H), 0.97~0.93(m, 6H), 0.89~0.81(m, 18H)

[0180] [Synthesis Example 3] Synthesis of Compound A-28 Compound A-28 was synthesized according to the following scheme.

[0181] [ka]

[0182] In a flask equipped with a Dean-Stark tube, 2.2 g of intermediate 6, 0.42 g of squaric acid, 10 mL of toluene, and 10 mL of n-butanol were added, mixed, and heated under reflux for 10 hours. After the reaction was completed, the reaction mixture was cooled to room temperature, and then 30 mL of methanol was added and stirred at room temperature for 2 hours. The resulting crystals were filtered, and the filtrate (crystals) was washed with methanol. The crude crystals obtained were further purified by silica gel column chromatography (hexane / ethyl acetate = 6 / 1) and then dried. In this way, 1.6 g (67%) of squarylium compound A-28 was obtained. Intermediate 6 was synthesized with reference to the synthesis method for intermediate 5 in [Synthesis Example 2].

[0183] The identification of the obtained squarylium compound A-28 was confirmed by nuclear magnetic resonance spectroscopy ( 1 H-NMR). 1 H-NMR(CDCl3):δ 12.40~12.03(m, 2H), 8.44~8.34(m, 4H), 8.12~7.90(m, 4H), 7.65~7.39( m, 4H), 7.37~7.27(m, 5H), 7.13~7.03(m, 5H), 6.35~6.32(m, 2H), 3.85~3. 75(m, 4H), 2.68~2.64(m, 4H), 1.85~1.79(m, 2H), 1.68~1.61(m, 4H), 1.51 ~1.33(m, 12H), 1.25~1.21(m, 8H), 0.98~0.94(m, 6H), 0.87~0.81(m, 12H)

[0184] [Synthesis Example 4] Synthesis of Compound A-4 Compound A-4 was synthesized according to the following scheme.

[0185] [ka]

[0186] 5.7 g of intermediate 7, 2.0 g of squaric acid dichloride, and 50 mL of toluene were added and heated to reflux for 8 hours. After the reaction was completed, 100 mL of water was added dropwise to the reaction mixture cooled to room temperature and stirred for 1 hour. 50 mL of toluene was then added to extract the organic layer. The organic layer was repeatedly washed with water and then concentrated under reduced pressure. 50 mL of acetic acid, 50 mL of water, and 4 mL of 2N aqueous hydrochloric acid were then added to the concentrated residue and heated to reflux for 8 hours. After the reaction was completed, the reaction mixture was cooled to room temperature, the reaction solvent was concentrated under reduced pressure, and 10 mL of methanol was added. After stirring at room temperature for 1 hour, the resulting crystals were filtered, washed with water and methanol, and then dried. 3.1 g (45%) of the desired intermediate 8 was thus obtained.

[0187] In a flask equipped with a Dean-Stark tube, 1.0 g of intermediate 8, 0.73 g of intermediate 9, 10 mL of toluene, and 10 mL of n-butanol were added, mixed, and heated under reflux for 2 hours. After the reaction was completed, the reaction mixture was cooled to 0°C, and the resulting crystals were filtered. The filtrate (crystals) was washed with methanol. The resulting crude crystals were purified by silica gel column chromatography (hexane / ethyl acetate = 2 / 1) and then dried. Thus, 1.1 g (68%) of the target compound A-4 was obtained. Intermediate 7 and Intermediate 9 were each synthesized with reference to the synthesis method for Intermediate 5 in [Synthesis Example 2].

[0188] The squarylium compound A-4 was identified by matrix-assisted laser desorption / ionization mass spectrometry (MALDI-MS). MS: m / z = 895.6 ([M+H] + )

[0189] For each synthesized compound, the maximum absorption wavelength λmax was measured and the solubility was evaluated in the same manner as in Test Examples 1 and 2, and the results are shown in Table 1. For comparative compounds C-1 to C-3, C-5, and C-6, the measured solubility was also shown. In Table 1, the numbers assigned to each squarylium compound correspond to the numbers of the exemplified squarylium compounds described above (the same applies to Tables 2 to 5).

[0190] [ka]

[0191] [Table 1]

[0192] [Example B] Preparation of resin composition, and production and evaluation of optical filters A resin composition (liquid composition) of the present invention was prepared using the squarylium compound synthesized in Example A, and then an optical filter was produced, and the light resistance and surface condition were evaluated. The materials used in this example are listed below. (Resin 1) Commercially available polystyrene (PS Japan, SGP-10, Tg: 100°C) was heated to 110°C and allowed to cool to room temperature (23°C) before use. (Resin 2) Commercially available Arton (manufactured by JSR Corporation, RX4500, Tg 140°C, cyclic polyolefin) was heated to 110°C and allowed to cool to room temperature before use. (Base film 1) A commercially available polyethylene terephthalate film, Lumirror (R) S105 (film thickness 38 μm, manufactured by Toray Industries, Inc.), was used as the substrate 1.

[0193] Example 28 (Preparation of Resin Composition) The components shown below were mixed (dissolved in a toluene / cyclohexanone mixed solvent) to prepare a resin solution S-1 as one form of the resin composition of the present invention. ------------------------------------------------------------------ Composition of resin solution S-1 Resin 1 100 parts by mass Squarylium compound B-12 1.49 parts by mass Toluene (solvent) 1710 parts by mass Cyclohexanone (solvent) 190 parts by mass -------------------------------------------------

[0194] The resulting resin solution S-1 was then filtered through a filter paper (#63, manufactured by Toyo Roshi Kaisha) with an absolute filtration accuracy of 10 μm, and further filtered through a sintered metal filter (FH025, manufactured by Pall Corporation) with an absolute filtration accuracy of 2.5 μm.

[0195] (Fabrication of optical filters) The resin solution S-1 after the above filtration treatment was applied to the substrate film 1 using a bar coater so that the thickness after drying would be 5.0 μm, and then dried at 100°C to produce an optical filter (resin film) 101 as a coated and dried product.

[0196] <Test Example 3> Evaluation of light resistance of optical filters The light resistance of the optical filter 101 prepared in Example 28 was evaluated based on the rate of change in absorbance (%). Specifically, the optical filter 101 was irradiated with light at 100,000 lux for 90 hours using a Super Xenon Weather Meter SX75 (trade name, manufactured by Suga Test Instruments Co., Ltd.) in an environment of 50°C and 50% relative humidity, and then the absorbance difference at the maximum absorption wavelength was measured and the absorbance change rate was calculated using the following formula. The results are shown in Table 2. (Absorbance change rate) (%) = [(difference in absorbance after 90 hours of irradiation) / (difference in absorbance before 90 hours of irradiation)] × 100 Here, the absorbance difference at the maximum absorption wavelength of the optical filter was determined as follows. Using a spectrophotometer UV3600 (Shimadzu Corporation), the absorbance in the wavelength range of 400 to 800 nm was measured in 1 nm increments for the optical filter 101 and a filter (blank) prepared in the same manner as the optical filter 101 except that it did not contain the squarylium compound B-12. The absorbance difference between the absorbance of the optical filter 101 at each wavelength and the absorbance of the filter (blank) was calculated, and the wavelength at which the absorbance difference was maximum was defined as the maximum absorption wavelength. In other words, the maximum absorbance difference was taken as the absorbance difference at the maximum absorption wavelength of the optical filter 101.

[0197] Test Example 4: Evaluation of the surface condition of optical filters The surface condition of the optical filter 101 produced in Example 28 was evaluated by visual observation using an optical microscope. Specifically, the optical filter 101 was observed at 200x bright field magnification at 10 random points using an optical microscope MX-61L (trade name, manufactured by Olympus Corporation). At each observation point, the presence or absence of unevenness in the resin film (irregularities such as linear scratches or protrusions on the surface, uneven distribution or aggregates of the squarylium compound within or on the film surface, etc.) was confirmed. Specifically, when linear scratches on the surface, irregularities due to repellency, and scattering or turbidity of the resin film due to precipitates resulting from uneven distribution or aggregate formation of the squarylium compound were visually recognized, it was determined that unevenness was present. The total number of observation points that showed a uniform film without any irregularities was added up out of the total 10 observation points, and the surface condition was evaluated according to the following evaluation criteria. The results are shown in Table 2. - Surface condition evaluation criteria - A: The total number of observation points is 9 or more. B: The total number of observation points is 6 or more and 8 or less. C: The total number of observation points is less than 6 points.

[0198] <Examples 1 to 15, 21 to 27, 29 to 34 and Comparative Examples 1 to 6> The resin compositions and optical filters of Examples 1 to 15, 21 to 27, 29 to 34 and Comparative Examples 1 to 6 were prepared or produced in the same manner as in Example 28, except that the resin, squarylium compound, and its content used in Example 28 were changed to those shown in Table 2. The thickness of each optical filter was also set to the same as that of optical filter 101 of Example 28. In Examples 11 to 13, 15, and 31 to 34 using Resin 2, the toluene / cyclohexanone mixed solvent was changed to a mixed solvent of 1,427 parts by mass of cyclohexane and 250 parts by mass of ethyl acetate in the preparation of the resin composition, and the base film 1 was changed to a triacetyl cellulose film ZRD40SL (trade name, manufactured by Fujifilm Corporation) in the production of the optical filter. Furthermore, since the comparative compounds C-1 to C-6 were not completely dissolved in the toluene / cyclohexanone mixed solvent at the following contents, the insoluble matter was filtered off and the obtained resin solution was used to prepare an optical filter for each compound. The light resistance and surface condition of each of the prepared optical filters were evaluated in the same manner as in Test Examples 3 and 4 above. The results are shown in Table 2.

[0199] [Table 2]

[0200] In Examples 1 to 15, 21 to 27, 29 to 34 and Comparative Examples 1 to 6, resin compositions were prepared and optical filters were fabricated in the same manner as in each Example or Comparative Example, except that the content of the squarylium compound was changed to 1.49 parts by mass, as in Example 28 (resin solution S-1). As a result, in all of Examples 1 to 15, 21 to 27, and 29 to 34 and Comparative Examples 1 to 6, the light fastness measurement results showed values ​​almost equivalent to the values ​​shown in Table 2, although they varied slightly from the values ​​shown in Table 2, and the same tendency of improvement in light fastness was confirmed. Furthermore, the surface state of the optical filter obtained was the same as that shown in Table 2. Thus, it was found that similar effects could be obtained even if the content of the squarylium compound in the resin composition and the optical filter was appropriately changed within the range specified in the present invention.

[0201] [Example C] Preparation of resin composition, and production and evaluation of optical filters The resin composition (liquid composition) of the present invention, prepared using the squarylium compound synthesized in Example A and a poly(meth)acrylic resin as resin 3, was coated and dried to produce an optical filter as a coated and dried product, and the light resistance and surface condition of the obtained optical filter were evaluated. <Example 107> A liquid resin composition was prepared by mixing 0.07 parts by mass of squarylium compound B-12, 14 parts by mass of a propylene glycol monomethyl ether acetate solution containing 40% by mass of resin 3: benzyl methacrylate / methacrylic acid copolymer (molar ratio = 70 / 30, Tg = 80 to 90°C), and 30 parts by mass of tetrahydrofuran to dissolve the squarylium compound and resin 3. The resulting resin composition was spin-coated onto a glass substrate (rotation speed 500 rpm, 30 seconds) to form a coating film, which was then dried at 110°C for 2 minutes to produce a dried coating (resin film) with a thickness of 10 μm.

[0202] Test Example 5: Evaluation of light resistance of coated and dried product For the coated and dried products prepared as described above, the rate of absorbance retention at the maximum absorption wavelength (λmax) was determined under the following (Condition 1) to evaluate lightfastness. Specifically, the absorbance of the coated and dried products at the maximum absorption wavelength (λmax) was measured, and then a lightfastness test was conducted after 50 hours of irradiation under the following (Condition 2), and the absorbance of the coated and dried products at the maximum absorption wavelength (λmax) after the lightfastness test was measured. The rate of change in absorbance at the maximum absorption wavelength (λmax) was calculated using the following formula. The results are shown in Table 3. Absorbance change rate (%) = [(absorbance at λmax after 50 hours of irradiation) / (absorbance at λmax before 50 hours of irradiation)] × 100 (Condition 1) The absorbance of the glass substrate on which the coating film was formed was measured at wavelength intervals of 1 nm in the wavelength range of 300 to 1000 nm using a spectrophotometer UV1900 (Shimadzu Corporation). (Condition 2) Equipment: Xenon weather meter (Suga Test Instruments: XL75) Illuminance: 10klx (40w / m 2 ) Exam duration: 50 hours Environment: 23°C, relative humidity 50%

[0203] Test Example 6: Evaluation of the surface condition of the dried coated product The surface condition of the coated and dried product was examined in the same manner as in Test Example 4. The results are shown in Table 3.

[0204] <Examples 101 to 106 and 108> The coated and dried products of Examples 101 to 106 and 108 were prepared in the same manner as in Example 107, except that the squarylium compound and its content (parts by mass) used in Example 107 were changed to those shown in Table 3. The thickness of each coated and dried product was also set to the same thickness as that of the coated and dried product of Example 107. The light resistance and surface condition of each of the prepared coated and dried products were evaluated in the same manner as in Test Examples 5 and 6 above. The results are shown in Table 3.

[0205] [Table 3]

[0206] [Example D] Preparation of resin composition, and production and evaluation of optical filters A resin composition (molten mixture) of the present invention was prepared using the squarylium compound synthesized in Example A and a polycarbonate resin as resin 4, and an optical filter was produced. The presence of precipitates of the squarylium compound in the obtained optical filter was evaluated. <Examples 201 to 208> A mixture was obtained by stirring 1 kg of polycarbonate resin (SD Polyca 301-30 (trade name), glass transition point 145-150°C, manufactured by Sumika Polycarbonate Co., Ltd.) and 0.4 g of a squarylium compound shown in Table 4 below in a stainless steel tumbler for 1 hour. The resulting mixture was melt-kneaded at 280-320°C for 1 minute using a twin-screw kneading extruder (KZW15TW-45 / 60MG-NH (trade name), manufactured by Technovel Co., Ltd.) to obtain a pellet-shaped melt-kneaded product. The pellet-shaped melt-kneaded product was dried at 80°C for 3 hours and then molded in a press to produce molded plates with a thickness of 0.15 mm. <Test Example 7> Each of the produced molded plates (polycarbonate films) was visually inspected for the presence or absence of precipitates of the squarylium compound. - Evaluation Criteria - A: No precipitates B: Precipitates present

[0207] [Table 4]

[0208] [Example E] Preparation of resin composition, and production and evaluation of optical filters A resin composition (molten mixture) of the present invention was prepared using the squarylium compound synthesized in Example A and polyethylene terephthalate resin as resin 5, and an optical filter was produced. The presence of precipitates of the squarylium compound in the obtained optical filter was evaluated. <Examples 301 to 308> 500 g of polyethylene terephthalate (TRN-8550F (trade name), melting point 252°C, manufactured by Teijin Limited) and 0.4 g of a squarylium compound shown in Table 5 below were stirred in a stainless steel tumbler for 1 hour to obtain a mixture. The obtained mixture was melt-kneaded at 270°C to obtain a molten kneaded product in the form of pellets. The obtained molten kneaded product in the form of pellets was dried at 80°C for 3 hours and then molded in a press to produce molded plates with a thickness of 0.15 mm. <Test Example 8> Each of the produced molded plates (PET films) was visually inspected for the presence or absence of precipitates of the squarylium compound. - Evaluation Criteria - A: No precipitates B: Precipitates present

[0209] [Table 5]

[0210] The results in Tables 1 to 5 reveal the following. It can be seen that the comparative compounds C-1 to C-3, C-5 and C-6 do not exhibit solubility in organic solvents, and the comparative compound C-4 exhibits solubility in organic solvents, but optical filters containing these comparative compounds cannot achieve both light resistance and surface appearance. This is because the comparative compounds C-1 and C-4 are 1 ~R 4 Although the comparative compound C-2 satisfies the conditions for the group R in formula (1), it does not have any branched alkyl group having 4 or more carbon atoms. 1 ~R 4 This is thought to be because all of the R in formula (1) are phenyl groups and there is no branched alkyl group having 4 or more carbon atoms. 1 ~R 4 Although it satisfies the possible groups as R 5 and R 6Although Comparative Example C-5 has a metallocene structure in the molecule, it is believed that the compound has a hydroxyl group as R in formula (4). 1 ~R 4 The reason for this is thought to be that the R in the formula (1) and the R in the formula (2) are all methyl groups, and furthermore, the compound has no branched alkyl group having 4 or more carbon atoms, and is therefore poor in solubility. 2 , R 4 Although all of these are alkyl groups having four carbon atoms, this is thought to be because they are linear rather than branched. In particular, comparative compounds C-1 to C-3 and C-5 have low solubility and tend to form aggregates, so the surface condition of the optical filters is also significantly inferior.

[0211] In contrast, the squarylium compounds of the present invention represented by formula (1) or (3) exhibit sufficient solubility in organic solvents while exhibiting a maximum absorption wavelength in the wavelength range of 670 to 740 nm. Furthermore, optical filters of the present invention containing these squarylium compounds exhibit excellent surface properties (with minimal variation during film formation) and become uniform membrane filters, regardless of their production method. Therefore, optical filters containing these squarylium compounds allow incident light to enter the filter without reflection, specifically absorb and block light in a specific wavelength range as insoluble wavelength light, and exhibit a higher absorbance change rate (lightfastness) than comparative optical filters. Furthermore, it can be seen that even when the squarylium compounds of the present invention are contained at high concentrations, resin compositions free of precipitates or deposits due to aggregation (association) of the squarylium compounds can be realized, as well as optical filters capable of specifically absorbing and blocking light in a specific wavelength range. Therefore, an image display device equipped with the optical filter of the present invention is expected to exhibit excellent light resistance, a wide color reproduction range, and spectral characteristics close to the relative luminosity curve, particularly on the long wavelength side, and a solid-state imaging device including the optical filter of the present invention is expected to exhibit excellent light resistance and excellent color reproduction. Furthermore, the optical filter of the present invention has excellent transmittance in the 400 to 600 nm range and excellent oblique incidence characteristics due to its lack of incidence angle dependency, and therefore can be suitably used as a highly light-resistant near-infrared cut filter.

[0212] While the present invention has been described in connection with embodiments thereof, we do not intend to limit our invention to any of the details of the description unless otherwise specified, and believe that the claims should be construed broadly without departing from the spirit and scope of the invention as set forth in the appended claims.

[0213] This application claims priority based on Japanese Patent Application No. 2020-217497 filed in Japan on December 25, 2020, and Japanese Patent Application No. 2021-196123 filed in Japan on December 2, 2021, the contents of which are incorporated herein by reference. [Explanation of symbols]

[0214] 1 Upper polarizer 2 Direction of absorption axis of upper polarizer 3. Liquid crystal cell electrode substrate 4. Alignment direction of electrode substrate on liquid crystal cell 5 Liquid crystal layer 6. Liquid crystal cell electrode substrate 7. Alignment direction of electrode substrate under liquid crystal cell 8 Lower polarizer 9 Direction of absorption axis of lower polarizer B Backlight unit 10 LCD display device

Claims

1. A resin composition containing a squarylium compound and a resin, The resin composition, wherein the squarylium compound comprises at least one selected from squarylium compounds represented by the following formula (1) and squarylium compounds represented by the following formula (3): 【Chemistry 1】 In the formula (1), R １ ~R ４ represents an alkyl group or an aryl group which may have a substituent, provided that R １ ~R ４ At least one of R is an aryl group; １ ~R ４ At least one of R is an alkyl group. ５ and R ６ Ha-NR ９ R １０ indicates R ９ and R １０ is a hydrogen atom, -COR Ｎ , -COOR Ｎ , -CON(R Ｎ ) ２ or -SO ２ R Ｎ indicates R Ｎ represents a hydrogen atom or an alkyl or aryl group which may have a substituent. ７ and R ８ represents a substituent, and m and n are integers of 0 to 3. However, the squarylium compound represented by the formula (1) has at least one branched alkyl group having 4 or more carbon atoms. 【Chemistry 2】 In the formula (3), Dye represents a structural portion obtained by removing n1 hydrogen atoms from a compound represented by the following formula (4), and Q １ represents a group represented by the following formula (4M), and n1 is an integer of 1 to 6. 【Transformation 3】 In the formula (4), R １ ~R ４ represents an alkyl group or an aryl group which may have a substituent, provided that R １ ~R ４ At least one of R is an aryl group; １ ~R ４ At least one of R is an alkyl group. ５ and R ６ Ha-NR ９ R １０ indicates R ９ and R １０ is a hydrogen atom, -COR Ｎ , -COOR Ｎ , -CON(R Ｎ ) ２ or -SO ２ R Ｎ indicates R Ｎ represents a hydrogen atom or an alkyl or aryl group which may have a substituent. ７ and R ８ represents a substituent, and m and n are integers of 0 to 3. 【Chemistry 4】 In the formula (4M), L represents a single bond or a divalent linking group that is not conjugated with Dye. １ｍ ~R ９ｍ represents a hydrogen atom or a substituent, and M represents Fe, Co, Ni, Ti, Cu, Zn, Zr, Cr, Mo, Os, Mn, Ru, Sn, Pd, Rh, V, or Pt. * indicates the bond with dye.

2. The resin composition according to claim 1, wherein the squarylium compound represented by formula (1) is represented by the following formula (2): 【Transformation 5】 In the formula (2), R ２ and R ４ represents an alkyl group. １１ and R １２ represents a substituent, and p and q are integers of 0 to 5. ５ ~R ８ , m and n are R in the formula (1) ５ ~R ８ , m and n are synonymous with each other. However, the squarylium compound represented by the formula (2) has at least one branched alkyl group having 4 or more carbon atoms.

3. R ２ , R ４ , R ９ and R １０ The resin composition according to claim 1 or 2, wherein at least one of the above groups contains a branched alkyl group having 4 or more carbon atoms.

4. The resin composition according to claim 1, wherein the compound represented by formula (4) is represented by the following formula (5): 【Transformation 6】 In the formula (5), R ２ and R ４ represents an alkyl group. １１ and R １２ represents a substituent, and p and q are integers of 0 to 5. ５ ~R ８ , m and n are R in the formula (4) ５ ~R ８ , m and n are synonymous with each other.

5. The resin composition according to claim 1 or 4, wherein the compound represented by formula (4) or the compound represented by formula (5) has at least one branched alkyl group having 4 or more carbon atoms.

6. The resin composition according to claim 1 , 4 or 5, wherein M in formula (4M) is Fe.

7. The resin composition according to any one of claims 1 to 6, wherein the resin has a glass transition temperature of -80 to 200°C.

8. The resin composition according to any one of claims 1 to 7, wherein the resin is at least one selected from the group consisting of polystyrene resin, cellulose acylate resin, poly(meth)acrylic resin, polyester resin, cycloolefin resin, and polycarbonate resin.

9. 9. The resin composition according to claim 1, further comprising a solvent having a boiling point of 200° C. or less, in which the resin and the squarylium compound are dissolved.

10. A dried coated product obtained by coating and drying the resin composition according to claim 9 on a substrate.

11. A melt-kneaded product of the resin composition according to any one of claims 1 to 8.

12. An optical filter comprising the resin composition according to any one of claims 1 to 7, the coated and dried product according to claim 10, or the melt-kneaded product according to claim 11.

13. The optical filter according to claim 12, which is in the form of a membrane or film.

14. An image display device comprising the optical filter according to claim 12 or 13.

15. A solid-state imaging device comprising the optical filter according to claim 12 or 13.

16. A squarylium compound represented by the following formula (1) or (3): 【Transformation 7】 In the formula (1), R １ ~R ４ represents an alkyl group or an aryl group which may have a substituent, provided that R １ ~R ４ At least one of R is an aryl group; １ ~R ４ At least one of R is an alkyl group. ５ and R ６ Ha-NR ９ R １０ indicates R ９ and R １０ is a hydrogen atom, -COR Ｎ , -COOR Ｎ , -CON(R Ｎ ) ２ or -SO ２ R Ｎ indicates R Ｎ represents a hydrogen atom, or an alkyl or aryl group which may have a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group or an acyl group as a substituent. ７ and R ８ represents a substituent, and m and n are integers of 0 to 3. However, the squarylium compound represented by the formula (1) has at least one branched alkyl group having 4 or more carbon atoms. 【Transformation 8】 In the formula (3), Dye represents a structural portion obtained by removing n1 hydrogen atoms from a compound represented by the following formula (4), and Q １ represents a group represented by the following formula (4M), and n1 is an integer of 1 to 6. 【Chemistry 9】 In the formula (4), R １ ~R ４ represents an alkyl group or an aryl group which may have a substituent, provided that R １ ~R ４ At least one of R is an aryl group; １ ~R ４ At least one of R is an alkyl group. ５ and R ６ Ha-NR ９ R １０ indicates R ９ and R １０ is a hydrogen atom, -COR Ｎ , -COOR Ｎ , -CON(R Ｎ ) ２ or -SO ２ R Ｎ indicates R Ｎ represents a hydrogen atom or an alkyl or aryl group which may have a substituent. ７ and R ８ represents a substituent, and m and n are integers of 0 to 3. 【Chemistry 10】 In the formula (4M), L represents a single bond or a divalent linking group that is not conjugated with Dye. １ｍ ~R ９ｍ represents a hydrogen atom or a substituent, and M represents Fe, Co, Ni, Ti, Cu, Zn, Zr, Cr, Mo, Os, Mn, Ru, Sn, Pd, Rh, V, or Pt. * indicates the bond with dye.

17. The squarylium compound according to claim 16, wherein the squarylium compound represented by formula (1) is represented by the following formula (2): 【Chemistry 11】 In the formula (2), R ２ and R ４ represents an alkyl group. １１ and R １２ represents a substituent, and p and q are integers of 0 to 5. ５ ~R ８ , m and n are R in the formula (1) ５ ~R ８ , m and n are synonymous with each other. However, the squarylium compound represented by the formula (2) has at least one branched alkyl group having 4 or more carbon atoms.

18. The squarylium compound according to claim 16, wherein the compound represented by formula (4) is represented by the following formula (5): 【Chemistry 12】 In the formula (5), R ２ and R ４ represents an alkyl group. １１ and R １２ represents a substituent, and p and q are integers of 0 to 5. ５ ~R ８ , m and n are R in the formula (4) ５ ~R ８ , m and n are synonymous with each other.

19. A method for producing a squarylium compound, comprising reacting a compound represented by the following formula (A) with squaric acid or a compound represented by the following formula (B) to produce a squarylium compound represented by the following formula (1): 【Chemistry 13】 In the formula (A), the formula (B) and the formula (1), R １ ~R ４ represents an alkyl group or an aryl group which may have a substituent. ５ and R ６ Ha-NR ９ R １０ indicates R ９ and R １０ is a hydrogen atom, -COR Ｎ , -COOR Ｎ , -CON(R Ｎ ) ２ or -SO ２ R Ｎ indicates R Ｎ R represents an alkyl group or an aryl group which may have a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group or an acyl group as a substituent. ７ and R ８ represents a substituent, and m and n are integers of 0 to 3. However, in the compound represented by formula (A) to be reacted with squaric acid, R １ and R ２ At least one of R is an aryl group; １ and R ２ At least one of them is an alkyl group, and has at least one branched alkyl group having 4 or more carbon atoms. In the compounds represented by the formula (A) or the formula (B) that are reacted with each other, R １ ~R ４ At least one of R is an aryl group; １ ~R ４ At least one of them is an alkyl group, and has at least one branched alkyl group having 4 or more carbon atoms. The squarylium compound represented by the formula (1) has at least one branched alkyl group having 4 or more carbon atoms.

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