Azo compound or salt thereof, and polarizing film containing same, polarizing plate, and display device

Abstract

Provided is an azo compound represented by formula (0) or a salt thereof. In formula (0), X represents an amino group that may have a substituent or a phenylamino group that may have a substituent, Q and R1 to R5 each independently represent a substituent, n represents an integer of 1 to 3, and s, t, u, and v each independently represent an integer of 0 to 2.

Description

Azo compounds or salts thereof, and polarizing films, polarizing plates, and displays containing the same

[0001] The present invention relates to a novel azo compound or a salt thereof, and a polarizing film, a polarizing plate and a display device containing the same.

[0002] Polarizing plates, which have the function of transmitting and blocking light, are fundamental components of display devices such as liquid crystal displays (LCDs), along with liquid crystals, which have a light switching function. Applications of LCDs range from small devices such as early calculators and clocks to laptops, word processors, LCD projectors, LCD televisions, car navigation systems, and indoor and outdoor measuring instruments. Polarizing plates can also be applied to lenses with polarization functions, and have been used in sunglasses with improved visibility and, in recent years, polarized glasses compatible with 3D televisions. As the applications of polarizing plates expand widely, they are used under a wide range of conditions, from low to high temperatures, low to high humidity, and low to high light intensity, creating a demand for polarizing plates with high polarization performance and durability.

[0003] Currently, polarizing plates are manufactured by dyeing or impregnating a film of polyvinyl alcohol or its derivative with iodine or a dichroic dye, stretching it, and then orienting it, or by dehydrochlorinating a polyvinyl chloride film or dehydrating a polyvinyl alcohol film to produce a polyene, which is then oriented. Iodine-based polarizing films generally have excellent polarization performance but are vulnerable to water and heat, resulting in poor durability when used for long periods of time under high temperature and humidity conditions. While methods for improving durability have been considered, such as treating the film with an aqueous solution containing formalin or boric acid, or using a polymer film with low moisture permeability as a protective film, these methods are not sufficiently effective. On the other hand, dye-based polarizing films generally have poorer performance than iodine-based polarizing films.

[0004] Dye-based polarizing films are generally produced using multiple color dyes to produce polarizing films with a wide variety of absorption bands suited to various purposes. For example, by mixing dyes selected from yellow to red, purple to blue, and blue-green to green, a polarizing film covering the entire visible wavelength range can be obtained, making it suitable for use as a polarizing plate in a display device. In recent years, LED backlights using light-emitting diodes (LEDs) as light sources have become mainstream in display devices, and photometric colorimetry using LED light sources is defined in JIS Z8724:2015. This standard specifies the wavelength range of color-matching functions as 360 nm to 830 nm, and also specifies that the wavelength range may be 380 nm to 780 nm when spectroscopically measuring an LED light source for colorimetry purposes. Therefore, it is obvious that for applications such as display devices using LED backlights, it is preferable for the polarizing plate to exhibit high optical properties in a wavelength range up to at least 780 nm.

[0005] However, in patents relating to polarizing plates for use in display devices that have been reported so far, many describe the wavelength range of optical measurement as 400 nm to 700 nm, as in Patent Document 1, and it appears that there has been no discussion of optical properties above 700 nm.

[0006] Patent Document 2 describes a case where an LED light source having almost no emission lines at 700 nm or above is used as the light source for a display device. However, even such LED light sources do not have zero emission lines at 700 nm or above, and some light sources have emission lines at 700 nm or above. Therefore, it can be said that using a polarizing film that exhibits polarization performance in the wavelength range of 700 nm or above is preferable because it can be widely applied without being limited to the type of light source.

[0007] An example of a dichroic dye having λmax around 700 nm that can handle the long wavelength region of 700 nm or more is a polarizing film containing an azo compound described in Patent Document 3. However, when a polarizing film was prepared with reference to the examples in this patent and its optical properties were measured, the degree of polarization at λmax at a single transmittance of around 44% and the degree of polarization at 700 nm or more remained low.

[0008] Copper complex azo compounds are known as azo compounds that are capable of operating in the long wavelength region. A method using an amine is commonly used to synthesize copper complex azo compounds. While various examples of the types of amines used are described in Patent Documents 3 and 4, there is no mention of amines being coordinated to copper. Thus, it is not believed that amine ligands significantly affect the performance of dichroic dyes, and thus no mention has been made of the effect of the type of amine coordinated to copper on the performance of azo compounds.

[0009] International Publication No. 2016 / 186183 Japanese Patent Application Laid-Open No. 2020-042111 International Publication No. 2017 / 135392 Japanese Patent Application Laid-Open No. 01-313568

[0010] "Dye Chemistry", by Yutaka Hosoda, Gihodo Publishing, 1957. "Application of Functional Dyes", supervised by Masahiro Irie, CMC Publishing Co., Ltd., 1st edition, pp. 98-100.

[0011] One object of the present invention is to provide a novel azo compound. Another object of the present invention is to provide a novel dichroic dye azo compound and a polarizing film and a polarizing plate containing the same, which have excellent polarizing performance. Another object of the present invention is to provide a polarizing film and a polarizing plate which have excellent polarizing performance even at wavelengths of 700 nm or more.

[0012] As a result of intensive research to achieve this object, the present inventors have found a novel azo compound that can be used as a dichroic dye for forming a polarizing film and a polarizing plate, and have also found that the use of this azo compound can realize a polarizing film and a polarizing plate having excellent polarization performance, thereby completing the present invention.

[0013] That is, the present invention relates to the following [1] to [7], but is not limited thereto. [1] An azo compound represented by the following formula (0) or a salt thereof: (In formula (0), X represents an amino group which may have a substituent, or a phenylamino group which may have a substituent; Q and R １ ~R ５each independently represents an arbitrary substituent, n represents an integer of 1 to 3, and s, t, u, and v each independently represent an integer of 0 to 2. [2] In formula (0), Q represents a C group having a hydrogen atom, a carboxy group, or a sulfo group. １ -C ４ is an alkoxy group, R １ ~R ５ are each independently a hydrogen atom, C １ -C ４ Alkyl group, C １ -C ４ C having an alkoxy group or a sulfo group １ -C ４ an alkoxy group, X is unsubstituted or C １ ~C ４ C having an alkoxy group or a sulfo group １ -C ４ Alkoxy group, C １ ~C ４ a phenylamino group having one or two substituents selected from the group consisting of an alkyl group, a carboxy group, a hydroxy group, a sulfo group, and an amino group, or an unsubstituted or one or two C １ ~C ４ [3] The azo compound or salt thereof according to [1], wherein the azo compound or salt thereof represented by formula (0) is represented by the following formula (2) or a salt thereof: (In formula (2), R １ ~R ４ are each independently a hydrogen atom, C １ -C ４ Alkyl group, C １ -C ４ C having an alkoxy group or a sulfo group １ -C ４ [4] The azo compound or a salt thereof according to [1], wherein the azo compound or a salt thereof represented by the formula (0) is represented by the following formula (3) or a salt thereof: (In formula (3), n represents an integer of 1 to 3.) [5] A polarizing film containing a substrate, characterized in that the azo compound or salt thereof according to any one of [1] to [4] is contained in the substrate. [6] A polarizing plate comprising transparent protective films provided on one side and both sides of the polarizing film according to [5]. [7] A display device comprising the polarizing plate according to [6].

[0014] The azo compound or a salt thereof of the present invention is useful as a dichroic dye for a polarizing film, and it has been found that by using N-methylethanolamine as the amine species in the synthesis step (cupration reaction) instead of commonly used ammonia water or monoethanolamine (hydroxyethylamine), the polarizing performance of the polarizing film is superior to that when other amine species are used. Furthermore, in one aspect, the polarizing film and polarizing plate of the present invention exhibit excellent polarizing performance in the wavelength range of 700 nm or more.

[0015] In this specification and claims, unless it clearly represents a free form, "azo compounds or salts thereof" may be simply referred to as "azo compounds." In this specification and claims, since "substituents" may contain hydrogen atoms, hydrogen atoms may be described as "substituents" for convenience. "Optionally substituted" means that the case where no substituent is present is also included. For example, "optionally substituted phenyl group" includes a simple unsubstituted phenyl group and a substituted phenyl group.

[0016] The azo compound or a salt thereof of the present invention is represented by the following formula (0). (In formula (0), X represents an amino group which may have a substituent, or a phenylamino group which may have a substituent; Q and R １ ~R ５ each independently represents an arbitrary substituent, n represents an integer of 1 to 3, and s, t, u, and v each independently represent an integer of 0 to 2.

[0017] When s, t, u, and v in formula (0) are 1, formula (0) is represented by the following formula (1).

[0018] In formulas (0) and (1), the ring structures drawn with solid and broken lines represent a phenyl (phenylene) group or a naphthyl (naphthylene) group.

[0019] In the above formulas (0) and (1), X represents an amino group which may have a substituent, or a phenylamino group which may have a substituent; Q and R １ ~R ５ Each of Q and R independently represents an optional substituent. １ ~R ５ Examples of the optional substituent in include a diazenyl group, a heterocyclic amino group, a fused-ring heterocyclic amino group, an alkyl group, an alkoxy group, an alkoxy group having a sulfo group, an aryloxy group, an alkylcarbonylamino group, an arylcarbonylamino group, an alkylcarbonyloxy group, an arylcarbonyloxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkylcarbamoyl group, an arylcarbamoyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonylamino group, an arylsulfonylamino group, an alkylsulfamoyl group, an arylsulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, an alkylthio group, an arylthio group, an alkylureido group, an arylureido group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, an alkylamino group, an arylamino group, a hydroxy group (—OH), a cyano group (—CN), a nitro group (—NO ２ ), mercapto group (—SH), halogen atom, carboxy group (—CO ２ H), sulfo group (-SO ３ H), amino group (-NH ２ ), a hydrogen atom, etc. As will be described later, the "amino group which may have a substituent" and the "phenylamino group which may have a substituent" as X, and the "amino group which may have a substituent" and the "phenylamino group which may have a substituent" as Q and R １ ~R ５ may be the structure at the corresponding position in formula (2) or (3).

[0020] The heterocyclic amino group includes a 5- or 6-membered heterocyclic amino group containing 1 to 3 heteroatoms selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom. Specific examples of such heterocyclic amino groups include: 5-membered heteroalicyclic amino groups such as pyrrolidinylamino, tetrahydrofurylamino, tetrahydrothiophen-2-ylamino, and tetrahydrothiophen-3-ylamino; 6-membered heteroalicyclic amino groups such as piperidinylamino, piperazinylamino, dioxan-2-ylamino, morpholinylamino, and thiomorpholinylamino; 5-membered aromatic heterocyclic amino groups such as pyrroleamino, pyrazoleamino, imidazoleamino, triazoleamino, furylamino, thiophen-2-ylamino, thiophen-3-ylamino, oxazoleamino, and thiazoleamino; and 6-membered aromatic heterocyclic amino groups such as pyridylamino, pyrazylamino, pyridazinylamino, and triazinylamino. The heterocyclic ring preferably has a heterocyclic moiety that is an aromatic ring, and the heteroatom constituting the heterocyclic ring is preferably selected from a nitrogen atom and a sulfur atom.

[0021] Examples of the fused heterocyclic amino group include fused 5- or 6-membered heterocyclic amino groups in which one benzene ring is fused to a 5- or 6-membered heterocycle containing 1 to 3 heteroatoms selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom. Specific examples of such fused heterocyclic amino groups include: fused heteroalicyclic amino groups having a 5-membered alicyclic heterocyclic moiety, such as phthalanylamino; fused heteroalicyclic amino groups having a 6-membered alicyclic heterocyclic moiety, such as benzopyranylamino; fused aromatic heterocyclic amino groups having a 5-membered aromatic heterocyclic moiety, such as benzopyrroleamino, benzopyrazoleamino, benzimidazoleamino, benzotriazoleamino, benzofuranylamino, benzothiophen-2-ylamino, benzothiophen-3-ylamino, benzoxazoleamino, and benzothiazoleamino; and fused aromatic heterocyclic amino groups having a 6-membered aromatic heterocyclic moiety, such as quinolinylamino, cinnolinylamino, phthalazinylamino, quinazolinylamino, and quinoxalinylamino. The heterocyclic moiety of the heterocycle is preferably an aromatic ring. Furthermore, the heteroatom constituting the heterocycle is preferably selected from nitrogen and sulfur atoms.

[0022] The alkyl group is a linear, branched or cyclic alkyl group, preferably C １ -C １０ Examples of the alkyl group include C. １ -C １０ Specific examples of the alkyl group include linear C alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl. １ -C １０ Alkyl groups: branched C alkyl groups such as isopropyl, isobutyl, sec-butyl, t-butyl, isoamyl, t-amyl, isohexyl, t-hexyl, isoheptyl, t-heptyl, isooctyl, t-octyl, 2-ethylhexyl, isononyl, and isodecyl. ３ -C １０ an alkyl group; or a cyclic C group such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, or cycloheptyl. ３ -C７ Among these, a linear or branched alkyl group is preferred, and C １ -C ４ A straight chain alkyl group of the formula is more preferred.

[0023] The alkoxy group is a linear, branched or cyclic alkoxy group, preferably a C １ -C １０ Examples of the alkyl group include an alkoxy group. １ -C １０ Specific examples of the alkoxy group include linear C alkoxy groups such as methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, n-hexyloxy, n-heptoxy, n-octyloxy, n-nonyloxy, and n-decyloxy. １ -C １０ Alkoxy groups: branched C alkoxy groups such as isopropoxy, isobutoxy, sec-butoxy, t-butoxy, isoamyloxy, t-amyloxy, isohexyloxy, t-hexyloxy, isoheptoxy, t-heptoxy, isooctyloxy, t-octyloxy, 2-ethylhexyloxy, isononyloxy, and isodecyloxy. ３ -C １０ an alkoxy group; or a cyclic C group such as cyclopropoxy, cyclobutoxy, cyclopentoxy, cyclohexyloxy, or cycloheptoxy; ３ -C ７ Among these, a linear or branched alkoxy group is preferred, and C １ -C ４ A linear alkoxy group of the formula is more preferred.

[0024] The alkoxy group having a sulfo group is preferably a linear alkoxy group, and the substitution position of the sulfo group is preferably the terminal of the alkoxy group. １ -C ４ Alkoxy groups of the formula (I) are preferred, 3-sulfopropoxy group and 4-sulfobutoxy group are more preferred, and 3-sulfopropoxy group is particularly preferred.

[0025] The aryloxy group is preferably C ６ -C １２It is an aryloxy group, and specific examples include phenoxy, naphthyloxy, biphenyloxy, and the like.

[0026] The alkylcarbonylamino group may be a linear, branched or cyclic alkylcarbonylamino group, preferably a C １ -C １０ Examples of the alkyl group include an alkylcarbonylamino group. １ -C １０ Specific examples of the alkylcarbonylamino group include straight-chain C alkylamino groups such as methylcarbonylamino (acetylamino), ethylcarbonylamino, n-propylcarbonylamino, n-butylcarbonylamino, n-pentylcarbonylamino, n-hexylcarbonylamino, n-heptylcarbonylamino, n-octylcarbonylamino, n-nonylcarbonylamino, and n-decylcarbonylamino. １ -C １０ alkylcarbonylamino groups; branched C alkylcarbonylamino groups such as isopropylcarbonylamino, isobutylcarbonylamino, sec-butylcarbonylamino, t-butylcarbonylamino, isoamylcarbonylamino, t-amylcarbonylamino, isohexylcarbonylamino, t-hexylcarbonylamino, isoheptylcarbonylamino, t-heptylcarbonylamino, isooctylcarbonylamino, t-octylcarbonylamino, 2-ethylhexylcarbonylamino, isononylcarbonylamino, and isodecylcarbonylamino; ３ -C １０ an alkylcarbonylamino group; or a cyclic C 1 group such as cyclopropylcarbonylamino, cyclobutylcarbonylamino, cyclopentylcarbonylamino, cyclohexylcarbonylamino, or cycloheptylcarbonylamino; ３ -C ７ Among these, a linear or branched alkylcarbonylamino group is preferred, and a linear alkylcarbonylamino group is more preferred.

[0027] The arylcarbonylamino group is preferably C ６ -C １２It is an arylcarbonylamino group, and specific examples include phenylcarbonylamino (benzoylamino), naphthylcarbonylamino, biphenylcarbonylamino, and the like.

[0028] The alkylcarbonyloxy group may be a linear, branched or cyclic alkylcarbonyloxy group, preferably a C １ -C １０ Examples of the alkyl group include an alkylcarbonyloxy group. １ -C １０ Specific examples of the alkylcarbonyloxy group include linear C alkylcarbonyloxy groups such as methylcarbonyloxy, ethylcarbonyloxy, n-propylcarbonyloxy, n-butylcarbonyloxy, n-pentylcarbonyloxy, n-hexylcarbonyloxy, n-heptylcarbonyloxy, n-octylcarbonyloxy, n-nonylcarbonyloxy, and n-decylcarbonyloxy. １ -C １０ Alkylcarbonyloxy groups include branched C alkylcarbonyloxy groups such as isopropylcarbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, t-butylcarbonyloxy, isoamylcarbonyloxy, t-amylcarbonyloxy, isohexylcarbonyloxy, t-hexylcarbonyloxy, isoheptylcarbonyloxy, t-heptylcarbonyloxy, isooctylcarbonyloxy, t-octylcarbonyloxy, 2-ethylhexylcarbonyloxy, isononylcarbonyloxy, and isodecylcarbonyloxy. ３ -C １０ an alkylcarbonyloxy group; or a cyclic C 1 group such as cyclopropylcarbonyloxy, cyclobutylcarbonyloxy, cyclopentylcarbonyloxy, cyclohexylcarbonyloxy, or cycloheptylcarbonyloxy; ３ -C ７ Among these, a linear or branched alkylcarbonyloxy group is preferred, and a linear alkylcarbonyloxy group is more preferred.

[0029] The arylcarbonyloxy group is preferably C ６-C １２ It is an arylcarbonyloxy group, and specific examples include phenylcarbonyloxy, naphthylcarbonyloxy, biphenylcarbonyloxy, and the like.

[0030] The alkylcarbonyl group may be a linear, branched or cyclic alkylcarbonyl group, preferably a C １ -C １０ Examples of the alkyl group include an alkylcarbonyl group. １ -C １０ Specific examples of the alkylcarbonyl group include linear C alkylcarbonyl groups such as methylcarbonyl, ethylcarbonyl, n-propylcarbonyl, n-butylcarbonyl, n-pentylcarbonyl, n-hexylcarbonyl, n-heptylcarbonyl, n-octylcarbonyl, n-nonylcarbonyl, and n-decylcarbonyl. １ -C １０ Alkylcarbonyl groups include branched C alkylcarbonyl groups such as isopropylcarbonyl, isobutylcarbonyl, sec-butylcarbonyl, t-butylcarbonyl, isoamylcarbonyl, t-amylcarbonyl, isohexylcarbonyl, t-hexylcarbonyl, isoheptylcarbonyl, t-heptylcarbonyl, isooctylcarbonyl, t-octylcarbonyl, 2-ethylhexylcarbonyl, isononylcarbonyl, and isodecylcarbonyl. ３ -C １０ an alkylcarbonyl group; or a cyclic C group such as cyclopropylcarbonyl, cyclobutylcarbonyl, cyclopentylcarbonyl, cyclohexylcarbonyl, or cycloheptylcarbonyl; ３ -C ７ Among these, a linear or branched alkylcarbonyl group is preferred, and a linear alkylcarbonyl group is more preferred.

[0031] The arylcarbonyl group is preferably C ６ -C １２ It is an arylcarbonyl group, and specific examples include phenylcarbonyl (benzoyl), naphthylcarbonyl, biphenylcarbonyl, and the like.

[0032] The alkylcarbamoyl group may be a linear, branched or cyclic monoalkylcarbamoyl group or a dialkylcarbamoyl group.

[0033] The monoalkylcarbamoyl group is preferably a mono-C １ -C １０ Specific examples of the alkylcarbamoyl group include linear mono-C alkylcarbamoyl groups such as methylcarbamoyl, ethylcarbamoyl, n-propylcarbamoyl, n-butylcarbamoyl, n-pentylcarbamoyl, n-hexylcarbamoyl, n-heptylcarbamoyl, n-octylcarbamoyl, n-nonylcarbamoyl, and n-decylcarbamoyl. １ -C １０ Alkylcarbamoyl groups: branched mono-C alkylcarbamoyl groups such as isopropylcarbamoyl, isobutylcarbamoyl, sec-butylcarbamoyl, t-butylcarbamoyl, isoamylcarbamoyl, t-amylcarbamoyl, isohexylcarbamoyl, t-hexylcarbamoyl, isoheptylcarbamoyl, t-heptylcarbamoyl, isooctylcarbamoyl, t-octylcarbamoyl, 2-ethylhexylcarbamoyl, isononylcarbamoyl, and isodecylcarbamoyl. ３ -C １０ an alkylcarbamoyl group; or a cyclic mono-C group such as cyclopropylcarbamoyl, cyclobutylcarbamoyl, cyclopentylcarbamoyl, cyclohexylcarbamoyl, or cycloheptylcarbamoyl; ３ -C ７ Among these, a linear or branched monoalkylcarbamoyl group is preferred, and a linear monoalkylcarbamoyl group is more preferred.

[0034] The dialkylcarbamoyl group is preferably a diC １ -C １０Specific examples of the alkylcarbamoyl group include linear di-C alkylcarbamoyl groups such as dimethylcarbamoyl, diethylcarbamoyl, di-n-propylcarbamoyl, di-n-butylcarbamoyl, di-n-pentylcarbamoyl, di-n-hexylcarbamoyl, di-n-heptylcarbamoyl, di-n-octylcarbamoyl, di-n-nonylcarbamoyl, and di-n-decylcarbamoyl. １ -C １０ Alkylcarbamoyl groups include branched di-C alkyl groups having two branched chains, such as diisopropylcarbamoyl, diisobutylcarbamoyl, di-sec-butylcarbamoyl, di-t-butylcarbamoyl, diisoamylcarbamoyl, di-t-amylcarbamoyl, diisohexylcarbamoyl, di-t-hexylcarbamoyl, diisoheptylcarbamoyl, di-t-heptylcarbamoyl, diisooctylcarbamoyl, di-t-octylcarbamoyl, di-(2-ethylhexyl)carbamoyl, diisononylcarbamoyl, and diisodecylcarbamoyl. ３ -C １０ an alkylcarbamoyl group; or a cyclic di-C group having two rings, such as dicyclopropylcarbamoyl, dicyclobutylcarbamoyl, dicyclopentylcarbamoyl, dicyclohexylcarbamoyl, or dicycloheptylcarbamoyl; ３ -C ７ Among these, a linear or branched dialkylcarbamoyl group is preferred, and a linear dialkylcarbamoyl group is more preferred.

[0035] The arylcarbamoyl group includes a monoarylcarbamoyl group and a diarylcarbamoyl group.

[0036] The monoarylcarbamoyl group is preferably a monoC ６ -C １２ It is an arylcarbamoyl group, and specific examples include phenylcarbamoyl, naphthylcarbamoyl, biphenylcarbamoyl, and the like.

[0037] The diarylcarbamoyl group is preferably a di-C ６ -C １２It is an arylcarbamoyl group, and specific examples include diphenylcarbamoyl, dinaphthylcarbamoyl, and di(biphenyl)carbamoyl.

[0038] The alkoxycarbonyl group is a linear, branched or cyclic alkoxycarbonyl group, preferably a C １ -C １０ Examples of the alkyl group include an alkoxycarbonyl group. １ -C １０ Specific examples of the alkoxycarbonyl group include linear C alkoxycarbonyl groups such as methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, n-butoxycarbonyl, n-pentoxycarbonyl, n-hexyloxycarbonyl, n-heptoxycarbonyl, n-octyloxycarbonyl, n-nonyloxycarbonyl, and n-decyloxycarbonyl. １ -C １０ Alkoxycarbonyl groups include branched C alkoxycarbonyl groups such as isopropoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, t-butoxycarbonyl, isoamyloxycarbonyl, t-amyloxycarbonyl, isohexyloxycarbonyl, t-hexyloxycarbonyl, isoheptoxycarbonyl, t-heptoxycarbonyl, isooctyloxycarbonyl, t-octyloxycarbonyl, 2-ethylhexyloxycarbonyl, isononyloxycarbonyl, and isodecyloxycarbonyl. ３ -C １０ an alkoxycarbonyl group; or a cyclic C alkoxycarbonyl group such as cyclopropoxycarbonyl, cyclobutoxycarbonyl, cyclopentoxycarbonyl, cyclohexyloxycarbonyl, or cycloheptoxycarbonyl; ３ -C ７ Among these, a linear or branched alkoxycarbonyl group is preferred, and a linear alkoxycarbonyl group is more preferred.

[0039] The aryloxycarbonyl group is preferably C ６ -C １２It is an aryloxycarbonyl group, and specific examples include phenoxycarbonyl, naphthyloxycarbonyl, biphenyloxycarbonyl, and the like.

[0040] The alkylsulfonylamino group may be a linear, branched or cyclic alkylsulfonylamino group, preferably a C １ -C １０ Examples of the alkylsulfonylamino group include alkylsulfonylamino groups. １ -C １０ Specific examples of the alkylsulfonylamino group include linear C alkylsulfonylamino groups such as methylsulfonylamino, ethylsulfonylamino, n-propylsulfonylamino, n-butylsulfonylamino, n-pentylsulfonylamino, n-hexylsulfonylamino, n-heptylsulfonylamino, n-octylsulfonylamino, n-nonylsulfonylamino, and n-decylsulfonylamino. １ -C １０ Alkyl sulfonylamino groups include branched C alkylsulfonylamino groups such as isopropyl sulfonylamino, isobutyl sulfonylamino, sec-butyl sulfonylamino, t-butyl sulfonylamino, isoamyl sulfonylamino, t-amyl sulfonylamino, isohexyl sulfonylamino, t-hexyl sulfonylamino, isoheptyl sulfonylamino, t-heptyl sulfonylamino, isooctyl sulfonylamino, t-octyl sulfonylamino, 2-ethylhexyl sulfonylamino, isononyl sulfonylamino, and isodecyl sulfonylamino. ３ -C １０ an alkylsulfonylamino group; or a cyclic C 1 group such as cyclopropylsulfonylamino, cyclobutylsulfonylamino, cyclopentylsulfonylamino, cyclohexylsulfonylamino, or cycloheptylsulfonylamino; ３ -C ７ Among these, a linear or branched alkylsulfonylamino group is preferred, and a linear alkylsulfonylamino group is more preferred.

[0041] The arylsulfonylamino group is preferably C ６ -C １２It is an arylsulfonylamino group, and specific examples include phenylsulfonylamino, toluenesulfonylamino, naphthylsulfonylamino, biphenylsulfonylamino, and the like.

[0042] The alkylsulfamoyl group may be a linear, branched or cyclic monoalkylsulfamoyl group or a dialkylsulfamoyl group.

[0043] The monoalkylsulfamoyl group is preferably a monoC １ -C １０ Specific examples of the alkylsulfamoyl group include linear mono-C alkylsulfamoyl groups such as methylsulfamoyl, ethylsulfamoyl, n-propylsulfamoyl, n-butylsulfamoyl, n-pentylsulfamoyl, n-hexylsulfamoyl, n-heptylsulfamoyl, n-octylsulfamoyl, n-nonylsulfamoyl, and n-decylsulfamoyl. １ -C １０ Alkylsulfamoyl groups: branched mono-C alkylsulfamoyl groups such as isopropylsulfamoyl, isobutylsulfamoyl, sec-butylsulfamoyl, t-butylsulfamoyl, isoamylsulfamoyl, t-amylsulfamoyl, isohexylsulfamoyl, t-hexylsulfamoyl, isoheptylsulfamoyl, t-heptylsulfamoyl, isooctylsulfamoyl, t-octylsulfamoyl, 2-ethylhexylsulfamoyl, isononylsulfamoyl, and isodecylsulfamoyl. ３ -C １０ an alkylsulfamoyl group; or a cyclic mono-C group such as cyclopropylsulfamoyl, cyclobutylsulfamoyl, cyclopentylsulfamoyl, cyclohexylsulfamoyl, or cycloheptylsulfamoyl; ３ -C ７ Among these, a linear or branched monoalkylsulfamoyl group is preferred, and a linear monoalkylsulfamoyl group is more preferred.

[0044] The dialkylsulfamoyl group is preferably a diC １ -C１０ Specific examples of the alkylsulfamoyl group include linear di-C alkylsulfamoyl groups such as dimethylsulfamoyl, diethylsulfamoyl, di-n-propylsulfamoyl, di-n-butylsulfamoyl, di-n-pentylsulfamoyl, di-n-hexylsulfamoyl, di-n-heptylsulfamoyl, di-n-octylsulfamoyl, di-n-nonylsulfamoyl, and di-n-decylsulfamoyl. １ -C １０ Alkyl sulfamoyl groups include branched di-C alkylsulfamoyl groups having two branched chains, such as diisopropylsulfamoyl, diisobutylsulfamoyl, di-sec-butylsulfamoyl, di-t-butylsulfamoyl, diisoamylsulfamoyl, di-t-amylsulfamoyl, diisohexylsulfamoyl, di-t-hexylsulfamoyl, diisoheptylsulfamoyl, di-t-heptylsulfamoyl, diisooctylsulfamoyl, di-t-octylsulfamoyl, di-(2-ethylhexyl)sulfamoyl, diisononylsulfamoyl, and diisodecylsulfamoyl. ３ -C １０ an alkylsulfamoyl group; or a cyclic di-C group having two rings, such as dicyclopropylsulfamoyl, dicyclobutylsulfamoyl, dicyclopentylsulfamoyl, dicyclohexylsulfamoyl, or dicycloheptylsulfamoyl; ３ -C ７ Among these, a linear or branched dialkylsulfamoyl group is preferred, and a linear dialkylsulfamoyl group is more preferred.

[0045] The arylsulfamoyl group includes a monoarylsulfamoyl group and a diarylsulfamoyl group.

[0046] The monoarylsulfamoyl group is preferably a monoC ６ -C １２ It is an arylsulfamoyl group, and specific examples include phenylsulfamoyl, naphthylsulfamoyl, biphenylsulfamoyl, and the like.

[0047] The diarylsulfamoyl group is preferably a diC ６ -C １２ It is an arylsulfamoyl group, and specific examples include diphenylsulfamoyl, dinaphthylsulfamoyl, and di(biphenyl)sulfamoyl.

[0048] The alkylsulfonyl group may be a linear, branched or cyclic alkylsulfonyl group, preferably a C １ -C １２ Examples of the alkylsulfonyl group include C. １ -C １２ Specific examples of the alkylsulfonyl group include linear C alkylsulfonyl groups such as methylsulfonyl, ethylsulfonyl, n-propylsulfonyl, n-butylsulfonyl, n-pentylsulfonyl, n-hexylsulfonyl, n-heptylsulfonyl, n-octylsulfonyl, n-nonylsulfonyl, n-decylsulfonyl, n-undecylsulfonyl, and n-dodecylsulfonyl. １ -C １２ Alkyl sulfonyl groups include branched C alkylsulfonyl groups such as isopropyl sulfonyl, isobutyl sulfonyl, sec-butyl sulfonyl, t-butyl sulfonyl, isoamyl sulfonyl, t-amyl sulfonyl, isohexyl sulfonyl, t-hexyl sulfonyl, isoheptyl sulfonyl, t-heptyl sulfonyl, isooctyl sulfonyl, t-octylsulfonyl, 2-ethylhexyl sulfonyl, isononyl sulfonyl, isodecyl sulfonyl, isoundecyl sulfonyl, t-undecyl sulfonyl, isododecyl sulfonyl, and t-dodecyl sulfonyl. ３ -C １２ an alkylsulfonyl group; or a cyclic C group such as cyclopropylsulfonyl, cyclobutylsulfonyl, cyclopentylsulfonyl, cyclohexylsulfonyl, or cycloheptylsulfonyl; ３ -C ７ Among these, a linear or branched alkylsulfonyl group is preferred, and a linear alkylsulfonyl group is more preferred.

[0049] The arylsulfonyl group is preferably C ６-C １２ It is an arylsulfonyl group, and specific examples include phenylsulfonyl, naphthylsulfonyl, biphenylsulfonyl, and the like.

[0050] The alkylthio group may be a linear, branched or cyclic alkylthio group, preferably a C １ -C １０ Examples of the alkylthio group include C. １ -C １０ Specific examples of the alkylthio group include linear C alkylthio groups such as methylthio, ethylthio, n-propylthio, n-butylthio, n-pentylthio, n-hexylthio, n-heptylthio, n-octylthio, n-nonylthio, and n-decylthio. １ -C １０ Alkylthio groups include branched C alkylthio groups such as isopropylthio, isobutylthio, sec-butylthio, t-butylthio, isoamylthio, t-amylthio, isohexylthio, t-hexylthio, isoheptylthio, t-heptylthio, isooctylthio, t-octylthio, 2-ethylhexylthio, isononylthio, and isodecylthio. ３ -C １０ an alkylthio group; or a cyclic C thio group such as cyclopropylthio, cyclobutylthio, cyclopentylthio, cyclohexylthio, or cycloheptylthio; ３ -C ７ Among these, a linear or branched alkylthio group is preferred, and a linear alkylthio group is more preferred.

[0051] The arylthio group is preferably C ６ -C １２ It is an arylthio group, and specific examples include phenylthio, naphthylthio, biphenylthio, and the like.

[0052] The alkylureido group may be a linear, branched or cyclic monoalkylureido group or a dialkylureido group.

[0053] The monoalkylureido group is preferably a monoC １ -C １０Specific examples of the alkylureido group include linear mono-C alkylureido groups such as methylureido, ethylureido, n-propylureido, n-butylureido, n-pentylureido, n-hexylureido, n-heptylureido, n-octylureido, n-nonylureido, and n-decylureido. １ -C １０ Alkylureido groups: branched mono-C alkylureido groups such as isopropylureido, isobutylureido, sec-butylureido, t-butylureido, isoamylureido, t-amylureido, isohexylureido, t-hexylureido, isoheptylureido, t-heptylureido, isooctylureido, t-octylureido, 2-ethylhexylureido, isononylureido, and isodecylureido. ３ -C １０ an alkylureido group; or a cyclic mono-C group such as cyclopropylureido, cyclobutylureido, cyclopentylureido, cyclohexylureido, or cycloheptylureido; ３ -C ７ Among these, a linear or branched alkylureido group is preferred, and a linear alkylureido group is particularly preferred.

[0054] The dialkylureido group is preferably a diC １ -C １０ Specific examples of alkylureido groups include linear di-C alkylureido groups such as dimethylureido, diethylureido, di-n-propylureido, di-n-butylureido, di-n-pentylureido, di-n-hexylureido, di-n-heptylureido, di-n-octylureido, di-n-nonylureido, and di-n-decylureido. １ -C １０alkylureido group; branched di-C alkyl ureido groups having two branched chains, such as diisopropylureido, diisobutylureido, di-sec-butylureido, di-t-butylureido, diisoamylureido, di-t-amylureido, diisohexylureido, di-t-hexylureido, diisoheptylureido, di-t-heptylureido, diisooctylureido, di-t-octylureido, di-(2-ethylhexyl)ureido, diisononylureido, and diisodecylureido; ３ -C １０ an alkylureido group; or a cyclic di-C group having two rings, such as dicyclopropylureido, dicyclobutylureido, dicyclopentylureido, dicyclohexylureido, or dicycloheptylureido; ３ -C ７ Among these, a linear or branched dialkylureido group is preferred, and a linear dialkylureido group is more preferred.

[0055] The arylureido group includes a monoarylureido group and a diarylureido group.

[0056] The monoarylureido group is preferably a monoC ６ -C １２ It is an arylureido group, and specific examples include phenylureido, naphthylureido, biphenylureido, and the like.

[0057] The diarylureido group is preferably a diC ６ -C １２ It is an arylureido group, and specific examples include diphenylureido, dinaphthylureido, and di(biphenyl)ureido.

[0058] The alkoxycarbonylamino group may be a linear, branched or cyclic alkoxycarbonylamino group, preferably a C １ -C １０ Examples of the alkyl group include an alkoxycarbonylamino group. １ -C １０Specific examples of the alkoxycarbonylamino group include linear C alkoxycarbonylamino groups such as methoxycarbonylamino, ethoxycarbonylamino, n-propoxycarbonylamino, n-butoxycarbonylamino, n-pentoxycarbonylamino, n-hexyloxycarbonylamino, n-heptoxycarbonylamino, n-octyloxycarbonylamino, n-nonyloxycarbonylamino, and n-decyloxycarbonylamino. １ -C １０ Alkoxycarbonylamino groups include branched C alkoxycarbonylamino groups such as isopropoxycarbonylamino, isobutoxycarbonylamino, sec-butoxycarbonylamino, t-butoxycarbonylamino, isoamyloxycarbonylamino, t-amyloxycarbonylamino, isohexyloxycarbonylamino, t-hexyloxycarbonylamino, isoheptoxycarbonylamino, t-heptoxycarbonylamino, isooctyloxycarbonylamino, t-octyloxycarbonylamino, 2-ethylhexyloxycarbonylamino, isononyloxycarbonylamino, and isodecyloxycarbonylamino. ３ -C １０ an alkoxycarbonylamino group; or a cyclic C alkoxycarbonylamino group such as cyclopropoxycarbonylamino, cyclobutoxycarbonylamino, cyclopentoxycarbonylamino, cyclohexyloxycarbonylamino, or cycloheptoxycarbonylamino; ３ -C ７ Among these, a linear or branched alkoxycarbonylamino group is preferred, and a linear alkoxycarbonylamino group is more preferred.

[0059] The aryloxycarbonylamino group is preferably C ６ -C １２ It is an aryloxycarbonylamino group, and specific examples include phenylcarbonylamino, naphthylcarbonylamino, biphenylcarbonylamino, and the like.

[0060] The alkylamino group may be a linear, branched, or cyclic monoalkylamino group or dialkylamino group.

[0061] The monoalkylamino group is preferably a monoC １ -C １０ Specific examples of the alkylamino group include linear mono-C alkylamino groups such as methylamino, ethylamino, n-propylamino, n-butylamino, n-pentylamino, n-hexylamino, n-heptylamino, n-octylamino, n-nonylamino, and n-decylamino. １ -C １０ Alkylamino groups: branched mono-C alkylamino groups such as isopropylamino, isobutylamino, sec-butylamino, t-butylamino, isoamylamino, t-amylamino, isohexylamino, t-hexylamino, isoheptylamino, t-heptylamino, isooctylamino, t-octylamino, 2-ethylhexylamino, isononylamino, and isodecylamino. ３ -C １０ alkylamino group; or a cyclic mono-C group such as cyclopropylamino, cyclobutylamino, cyclopentylamino, cyclohexylamino, or cycloheptylamino. ３ -C ７ Among these, a linear or branched monoalkylamino group is preferred, and a linear monoalkylamino group is more preferred.

[0062] The dialkylamino group is preferably a diC １ -C １０ Specific examples of the alkylamino group include linear di-C alkylamino groups such as dimethylamino, diethylamino, di-n-propylamino, di-n-butylamino, di-n-pentylamino, di-n-hexylamino, di-n-heptylamino, di-n-octylamino, di-n-nonylamino, and di-n-decylamino. １ -C １０Alkylamino groups: branched di-C alkylamino groups having two branched chains, such as diisopropylamino, diisobutylamino, di-sec-butylamino, di-t-butylamino, diisoamylamino, di-t-amylamino, diisohexylamino, di-t-hexylamino, diisoheptylamino, di-t-heptylamino, diisooctylamino, di-t-octylamino, di-(2-ethylhexyl)amino, diisononylamino, and diisodecylamino; ３ -C １０ an alkylamino group; or a cyclic di-C group having two rings, such as dicyclopropylamino, dicyclobutylamino, dicyclopentylamino, dicyclohexylamino, and dicycloheptylamino; ３ -C ７ Among these, a linear or branched dialkylamino group is preferred, and a linear dialkylamino group is more preferred.

[0063] The arylamino group may be a monoarylamino group or a diarylamino group.

[0064] The monoarylamino group is preferably a mono-C ６ -C １２ It is an arylamino group, and specific examples include phenylamino (anilino), naphthylamino, and biphenylamino.

[0065] The diarylamino group is preferably a diC ６ -C １２ It is an arylamino group, and specific examples include diphenylamino, dinaphthylamino, and di(biphenyl)amino.

[0066] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom, a chlorine atom, or a bromine atom being preferred.

[0067] More preferred examples of Q include C having a hydrogen atom, a carboxy group, or a sulfo group. １ -C ４ An alkoxy group is preferred. １ ~R ５Examples of the group include a hydrogen atom and C １ -C ４ Alkyl group, C １ -C ４ C having an alkoxy group or a sulfo group １ -C ４ An alkoxy group is particularly preferred. ５ As for C １ -C ４ More preferred examples of X include unsubstituted or C １ ~C ４ C having an alkoxy group or a sulfo group １ -C ４ Alkoxy group, C １ ~C ４ a phenylamino group having one or two substituents selected from the group consisting of an alkyl group, a carboxy group, a hydroxy group, a sulfo group, and an amino group, and an unsubstituted or one or two C １ ~C ４ An amino group having an alkyl group is preferable. １ ~C ４ and a phenylamino group having an alkoxy group. Preferably, n is 2 or 3. Preferably, s, t, u, and v each independently represent 0 or 1.

[0068] When the azo compound represented by formula (0) or (1) or a salt thereof is an azo compound represented by the following formula (2) or a salt thereof, a polarizing film having higher transmittance and a higher polarization degree can be provided, which is preferable. (In formula (2), R １ ~R ４ are each independently a hydrogen atom, C １ -C ４ Alkyl group, C １ -C ４ C having an alkoxy group or a sulfo group １ -C ４ represents an alkoxy group, and n represents an integer of 1 to 3. Preferably, n is 2 or 3.

[0069] In formula (0), formula (1) and formula (2), "C １ -C ４Examples of the "alkyl group" include straight-chain alkyl groups such as methyl, ethyl, n-propyl, and n-butyl, and branched-chain alkyl groups such as sec-butyl and tert-butyl.

[0070] In formula (0), formula (1) and formula (2), "C １ -C ４ Examples of the "alkoxy group" include a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, a sec-butoxy group, and a tert-butoxy group.

[0071] In the formula (0), the formula (1) and the formula (2), "C having a sulfo group" １ -C ４ The "alkoxy group" is preferably a straight-chain alkoxy group, and the substitution position of the sulfo group is preferably the terminal alkoxy group. More preferred are a 3-sulfopropoxy group and a 4-sulfobutoxy group, and particularly preferred is a 3-sulfopropoxy group.

[0072] The azo compound represented by formula (2) or a salt thereof is more preferably an azo compound represented by the following formula (3) or a salt thereof. (In formula (3), n represents an integer of 1 to 3.)

[0073] In the above formula (3), n has the same meaning as in formula (2).

[0074] The azo compound represented by the above formula (0) or (1) or a salt thereof can be easily produced by carrying out known diazotization and coupling in accordance with a typical method for producing azo compounds, such as that described in Non-Patent Document 1. The synthesis method will be illustrated using the azo compound of formula (1) as an example.

[0075] First, an aromatic amine represented by the following formula (A) is diazotized by a known method such as that described in Non-Patent Document 1, and then subjected to primary coupling with an aromatic amine represented by the following formula (B) to obtain a monoazoamino compound represented by the following formula (C). (In formulas (A) to (C), Q and R １ ~R ２ have the same meanings as in formula (1).

[0076] Next, this monoazoamino compound (C) is diazotized by a known method such as that described in Non-Patent Document 1, and subjected to secondary coupling with an aromatic amine of the following formula (D) to obtain a disazoamino compound represented by the following formula (E). (In formula (D) and formula (E), Q and R １ ~R ４ have the same meanings as in formula (1).

[0077] Next, the compound of formula (E) is diazotized by a known method such as that described in Non-Patent Document 1, and subjected to tertiary coupling with an aromatic amine substituted with a methoxy group of the following formula (F), to obtain a trisazoamino compound of the following formula (G).

[0078] Next, the compound of formula (G) is diazotized by a known method such as that described in Non-Patent Document 1, and subjected to quaternary coupling with a 4-hydroxynaphthalene-2-sulfonic acid having a substituent at the 7-position of the compound of formula (H) below, to obtain a tetrakisazo compound of formula (I) below.

[0079] Next, the azo compound of formula (1) is obtained by copperating the compound of formula (I) using copper sulfate and N-methylethanolamine by a known method such as that described in Patent Document 3.

[0080] In the above reaction, the diazotization step is carried out either by the normal method of mixing a nitrite such as sodium nitrite with an aqueous solution or suspension of the diazo component in a mineral acid such as hydrochloric acid or sulfuric acid, or by the reverse method of adding a nitrite to a neutral or weakly alkaline aqueous solution of the diazo component and then mixing this with a mineral acid. The diazotization temperature is suitably -10 to 40°C. The coupling step with aromatic amines is carried out by mixing each of the above diazo solutions with an acidic aqueous solution such as hydrochloric acid or acetic acid, under acidic conditions at a temperature of -10 to 40°C and a pH of 2 to 7.

[0081] The monoazo compound, disazo compound, or trisazo compound obtained by coupling can be used as is or precipitated by acid precipitation or salting out and filtered, or can be used in the next step as a solution or suspension. If the monoazo compound, disazo compound, or trisazo compound obtained by coupling is poorly soluble and in the form of a suspension, it can be filtered and used as a press cake in the next coupling step.

[0082] The coupling reaction between the diazotized trisazo compound and the naphthol represented by formula (H) is carried out at a temperature of −10 to 40° C. under neutral to alkaline conditions at a pH of 7 to 10. After completion of the reaction, the compound represented by formula (I) is precipitated by salting out and filtered out.

[0083] The copper-containing tetrakis azo compound of formula (1) can be obtained by adding copper sulfate and 2-methylaminoethanol to a tetrakis azo compound solution and reacting at 90°C or higher. After the reaction is complete, the compound is precipitated by salting out and then filtered. If purification is required, the salting out can be repeated or an organic solvent can be used to precipitate the compound from water. Examples of organic solvents used for purification include water-soluble organic solvents such as alcohols such as methanol and ethanol, and ketones such as acetone.

[0084] The compound of formula (1) prepared by the above procedure was subjected to TG-MS analysis using a Thermo Mass Photo 410 / S manufactured by Rigaku Corporation, and it was confirmed that the amine was coordinated to the dye.

[0085] When the aromatic amine represented by formula (A) which is a starting material for synthesizing the azo compound represented by formula (1) or a salt thereof is a substituted naphthylamine compound, for example, 2-aminonaphthalene-6-sulfonic acid, 2-aminonaphthalene-6,8-disulfonic acid, 2-aminonaphthalene-5,7-disulfonic acid, 2-aminonaphthalene-4,8-disulfonic acid, 2-aminonaphthalene-4,6,8-trisulfonic acid, 2-aminonaphthalene-3,6,8-trisulfonic acid, Phenylic acid, 2-amino-1-hydroxy-naphthalene-6-sulfonic acid, 3-amino-1-hydroxy-naphthalene-6-sulfonic acid, 2-amino-8-hydroxy-naphthalene-6-sulfonic acid, 3-amino-8-hydroxy-naphthalene-6-sulfonic acid, 2-amino-1,8-dihydroxy-naphthalene-6-sulfonic acid, 3-amino-1,8-dihydroxy-naphthalene-6-sulfonic acid, 2-amino-1,8-dihydroxy-naphthalene-3-sulfonic acid acid, 2-amino-1,8-dihydroxy-naphthalene-3,6-disulfonic acid, 2-amino-1-methoxy-8-hydroxy-naphthalene-6-sulfonic acid, 3-amino-1-methoxy-8-hydroxy-naphthalene-6-sulfonic acid, 2-amino-1-hydroxy-8-methoxy-naphthalene-6-sulfonic acid, 3-amino-1-hydroxy-8-methoxy-naphthalene-6-sulfonic acid, 2-amino-1-hydroxy-8-(3-sulfopropoxy)- Examples of the sulfonic acid include, but are not limited to, naphthalene-3-sulfonic acid, 2-amino-1-hydroxy-8-(4-sulfobutoxy)-naphthalene-3-sulfonic acid, 2-amino-1-(3-sulfopropoxy)-8-hydroxy-naphthalene-3-sulfonic acid, 2-amino-1-(4-sulfobutoxy)-8-hydroxy-naphthalene-3-sulfonic acid, and 2-amino-1,8-dihydroxy-naphthalene-6-aminomethyl-3-disulfonic acid. Preferred are 2-aminonaphthalene-6,8-disulfonic acid, 2-aminonaphthalene-5,7-disulfonic acid, 2-aminonaphthalene-4,8-disulfonic acid, and 2-aminonaphthalene-3,6,8-trisulfonic acid.

[0086] When the aromatic amine represented by formula (A), which is used as a starting material for synthesizing the azo compound represented by formula (2) or a salt thereof, is a substituted phenylamine compound, examples thereof include, but are not limited to, 4-sulfoaniline, 3-sulfoaniline, 2-sulfoaniline, 2,4-disulfoaniline, 2,5-disulfoaniline, 4-nitro-2-sulfoaniline, 2-nitro-4-sulfoaniline, 4-methoxy-2-sulfoaniline, 2-methoxy-4-sulfoaniline, 4-chloro-3-sulfoaniline, 4-(3-sulfopropoxy)-2-sulfoaniline, and 2-carboxy-4-sulfoaniline. Preferred are 4-sulfoaniline, 2,4-disulfoaniline, and 2-carboxy-4-sulfoaniline.

[0087] When the aromatic amines represented by formula (B), formula (D), and formula (F), which are starting materials for synthesizing the azo compound represented by formula (2) or a salt thereof, are substituted phenylamine compounds, for example, aniline, 2-methylaniline, 2-ethylaniline, 2-propylaniline, 2-butylaniline, 3-methylaniline, 3-ethylaniline, 3-propylaniline, 3-butylaniline, 2,5-dimethylaniline, 2,5-diethylaniline, 2-methoxyaniline, 2-ethoxyaniline, 2-propoxyaniline, 2-butoxyaniline, 3-methoxyaniline, 3-ethoxyaniline, 3-propoxyaniline, 3-butoxyaniline, 2-methoxy-5-methylaniline, 2,5-Dimethoxyaniline, 3-(2-amino-4-methylphenoxy)propane-1-sulfonic acid, 3-(2-aminophenoxy)propane-1-sulfonic acid, 4-(2-amino-4-methylphenoxy)butane-1-sulfonic acid, 4-(2-aminophenoxy)butane-1-sulfonic acid, 2-(2-amino-4-methylphenoxy)ethane-1-sulfonic acid, 2-(2-aminophenoxy)ethane-1-sulfonic acid, 3-(3-amino 4-(3-amino-4-methylphenoxy)propane-1-sulfonic acid, 3-(3-aminophenoxy)propane-1-sulfonic acid, 4-(3-amino-4-methylphenoxy)butane-1-sulfonic acid, 4-(3-aminophenoxy)butane-1-sulfonic acid, 2-(3-amino-4-methylphenoxy)ethane-1-sulfonic acid, 2-(3-aminophenoxy)ethane-1-sulfonic acid, 3-(2-amino-4-methoxyphenoxy)propane-1-sulfonic acid sulfonic acid, 4-(2-amino-4-methoxyphenoxy)butane-1-sulfonic acid, 2-(2-amino-4-methoxyphenoxy)ethane-1-sulfonic acid, 3-(3-amino-4-methoxyphenoxy)propane-1-sulfonic acid, 4-(3-amino-4-methoxyphenoxy)butane-1-sulfonic acid, 2-(3-amino-4-methoxyphenoxy)ethane-1-sulfonic acid, 3-(2-amino-4-ethoxyphenoxy)propane- Examples of aromatic amines include, but are not limited to, 1-sulfonic acid, 4-(2-amino-4-ethoxyphenoxy)butane-1-sulfonic acid, 2-(2-amino-4-ethoxyphenoxy)ethane-1-sulfonic acid, 3-(3-amino-4-ethoxyphenoxy)propane-1-sulfonic acid, 4-(3-amino-4-ethoxyphenoxy)butane-1-sulfonic acid, and 2-(3-amino-4-ethoxyphenoxy)ethane-1-sulfonic acid. Furthermore, the amino group of these aromatic amines may be protected. Examples of the protecting group include an ω-methanesulfonic group.

[0088] Specific examples of the azo compounds represented by the formula (0) or (1) or salts thereof are listed below. The azo compounds are represented in the form of free acids.

[0089] The azo compounds represented by the above formula (0) or (1) may be in the form of a free acid or a salt, and may also be salts of metal ions or ammonium ions. Examples of metal ions include alkali metal ions such as lithium ion, sodium ion, and potassium ion, and alkaline earth metal ions such as calcium ion and magnesium ion. Examples of ammonium ions include ammonium ion, methylammonium ion, dimethylammonium ion, triethylammonium ion, tetraethylammonium ion, tetra-n-propylammonium ion, tetra-n-butylammonium ion, monoethanolammonium ion, diethanolammonium ion, triethanolammonium ion, and N-methyl-N-monoethanolammonium ion. More specifically, in the case of a free acid, for example, sulfonic acid (-SO ３ H) in the case of sodium ions, and sodium sulfonate (-SO ３ Na), and for ammonium ions, ammonium sulfonate (-SO ３ NH ４ In the case of N-methyl-N-monoethanolammonium ion, it represents (-SO ３ － ・[MeNH ２ CH ２ CH ２ OH] ＋ )represent.

[0090] <Polarizing Film> The polarizing film of the present invention contains, as a dichroic dye, one or more azo compounds represented by the above formula (0) or (1) or salts thereof, and may further contain, as necessary, one or more organic dyes other than the azo compounds represented by the above formula (0) or (1). The other organic dye is not particularly limited, but is preferably a dye having absorption characteristics in a wavelength range different from the absorption wavelength range of the azo compounds represented by the above formula (0) or (1) or salts thereof and having high dichroism. Examples of the other organic dye include C.I. Direct Yellow 12, C.I. Direct Yellow 28, C.I. Direct Yellow 44, C.I. Direct Orange 26, C.I. Direct Orange 39, C.I. Direct Orange 71, C.I. Direct Orange 107, C.I. Direct Red 2, C.I. Direct Red 31, and C.I. Direct Red 107. Representative examples include dyes such as Red 79, C.I. Direct Red 81, C.I. Direct Red 247, C.I. Direct Blue 69, C.I. Direct Green 80, and C.I. Direct Green 59, as well as those described in Non-Patent Document 2. However, depending on the purpose, it is preferable to use dyes developed for polarizing plates such as those described in International Publication Nos. 2017 / 146212, 2019 / 117131, 2020 / 050333, and 2021 / 015188. These organic dyes are used as free acids, alkali metal salts (e.g., Na salts, K salts, Li salts), ammonium salts, or salts of amines.

[0091] The polarizing film of the present invention, which is produced using the azo compound represented by formula (0) or (1) or its salt as a dichroic dye and another dichroic dye, is a neutral gray polarizing film, a color polarizing film, etc., and can be used depending on the application. Here, "neutral gray" means that when two polarizing films are superimposed so that their orientation directions are perpendicular to each other (hereinafter also referred to as "orthogonal orientation"), there is little light leakage (color leakage) of a specific wavelength in the visible light wavelength range.

[0092] The degree of polarization at the maximum absorption wavelength of the polarizing film of the present invention is preferably 99.0% or more when the single transmittance Ts is 44.0±0.2%. Furthermore, the polarizing film of the present invention can be suitably used to control optical performance in the wavelength range of 700 nm or more. For example, in applications requiring high optical properties in the wavelength range of 700 nm or more, the desirable optical performance is such that, when the single transmittance Ts is 44.0±0.2%, the dichroic ratio at 700 nm is preferably 35.0 or more, more preferably 40.0 or more, and even more preferably 45.0 or more. Furthermore, the dichroic ratio at 720 nm is preferably 35.0 or more, more preferably 40.0 or more, and even more preferably 45.0 or more. Furthermore, when Ts is 44.0±0.2%, the degree of polarization at 700 nm and 720 nm is preferably 98.5% or more, more preferably 99.0% or more. By having such polarization performance, the polarizing film can provide a high-quality neutral gray polarizing film without color leakage.

[0093] When an azo compound of formula (0) or (1) or a salt thereof is used in combination with multiple dichroic dyes, the type of organic dye to be blended varies depending on whether the target polarizing film is a neutral gray polarizing film, a color polarizing film for liquid crystal projectors, or other color polarizing films. The blending ratio is not particularly limited, but generally, the total amount of at least one other organic dye is preferably in the range of 0.01 to 100 parts by mass, more preferably 0.1 to 10 parts by mass, per part by mass of the azo compound of formula (0) or (1) or a salt thereof.

[0094] When the intended polarizing film is a neutral gray polarizing film, the types and blending ratios of other organic dyes used in combination are adjusted so that the resulting polarizing film will have less color leakage in the visible light wavelength region.

[0095] When the intended polarizing film is a color polarizing film, the types and blending ratios of other organic dyes used in combination are adjusted so that the resulting polarizing film has a high single-plate average light transmittance in a specific wavelength range and a low average light transmittance in the orthogonal direction.

[0096] The polarizing film of the present invention can be produced by incorporating a dichroic dye containing an azo compound represented by the above formula (0) or (1) or a salt thereof and, if necessary, other dyes into a polarizing film substrate (also simply referred to as "substrate") by a known method, and then orienting the resulting dyes.

[0097] The polarizing film substrate is preferably a polymer film, and more preferably a film made of polyvinyl alcohol resin or a derivative thereof. Specific examples of polarizing film substrates include polyvinyl alcohol resins and those modified with olefins such as ethylene and propylene, or unsaturated carboxylic acids such as crotonic acid, acrylic acid, methacrylic acid, and maleic acid. Films made of polyvinyl alcohol resins or derivatives thereof are preferably used as polarizing film substrates from the viewpoint of dye adsorption and orientation. The thickness of the polarizing film substrate is typically 10 to 100 μm, and preferably about 20 to 80 μm.

[0098] When the polarizing film substrate is a polymer film, the azo compound of formula (0) or (1) or its salt is typically incorporated into the polymer film by dyeing the polymer film. Dyeing can be performed, for example, as follows: First, a dye bath is prepared by dissolving the azo compound of formula (0) or (1) or its salt, and, if necessary, other organic dyes, in water. The dye concentration in the dye bath is not particularly limited, but is typically selected from the range of about 0.001 to 10% by mass. If necessary, a dyeing assistant may also be used; for example, Glauber's salt is preferably used at a concentration of about 0.1 to 10% by mass. The polymer film can be dyed by immersing it in the dye bath prepared in this manner for, for example, 1 to 10 minutes. The dyeing temperature is preferably about 30 to 80°C.

[0099] Orientation of the azo compound represented by formula (0) or (1) or its salt is achieved by stretching a polymer film dyed with a dichroic dye. The stretching ratio is generally 2 to 9 times, preferably 3 to 8 times, and more preferably 4 to 7 times. Any known stretching method, such as a wet method or a dry method, may be used. Stretching of the polymer film may optionally be performed before dyeing. In this case, orientation of the water-soluble dye occurs at the time of dyeing. The oriented polymer film containing the water-soluble dye may be subjected to post-treatment such as boric acid treatment by a known method, if necessary. This post-treatment is performed for the purpose of improving the transmittance and polarization degree of the polarizing film. The conditions for the boric acid treatment vary depending on the type of polymer film and the type of dye used, but generally, the boric acid concentration of the boric acid aqueous solution is, for example, 0.1 to 15% by mass, preferably 1 to 10% by mass, at a treatment temperature of 30 to 80°C, preferably 40 to 75°C, and the film is immersed for 0.5 to 10 minutes. Furthermore, if necessary, a fixing treatment may also be carried out using an aqueous solution containing a cationic polymer compound.

[0100] <Polarizing Plate> The polarizing plate of the present invention (hereinafter also referred to as a "dye-based polarizing plate") can be obtained by laminating a transparent protective film on one or both sides of a polarizing film prepared using the compound of the present invention as a dichroic dye for controlling the transmittance in the long wavelength region. Materials for forming the transparent protective film are preferably those having excellent optical transparency, mechanical strength, thermal stability, moisture-blocking properties, etc. Examples of such materials include, but are not limited to, cellulose acetate films, acrylic films, fluorine-based films such as tetrafluoroethylene / hexafluoropropylene copolymers, and films made of polyester resins, polyolefin resins, or polyamide resins. The transparent protective film is preferably a triacetyl cellulose (TAC) film or a cycloolefin film, and the thickness of the protective film is preferably typically 10 to 200 μm. The transparent protective film is not limited to films. A protective layer made of an organic composition, inorganic composition, or a mixture thereof made of a material having excellent optical transparency, mechanical strength, thermal stability, moisture-blocking properties, etc. may also be formed on the polarizing film.

[0101] Furthermore, the polarizing film can be applied as a support-integrated polarizing plate in which a transparent substrate having a thickness greater than that of the film is attached to one or both sides of the polarizing film. Supports can be broadly divided into inorganic substrates and organic substrates, and examples of such substrates include inorganic substrates such as soda glass, borosilicate glass, quartz substrates, sapphire substrates, and spinel substrates, and organic substrates such as acrylic, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, and polyolefin.

[0102] A polarizing plate can use an adhesive or pressure-sensitive adhesive to bond the polarizing film to the transparent protective film or protective substrate. Examples of adhesives include thermosetting adhesives and ultraviolet-curing adhesives, and examples of such adhesives include, but are not limited to, polyvinyl alcohol adhesives, urethane emulsion adhesives, acrylic adhesives, and polyester-isocyanate adhesives. To improve adhesive strength or water resistance, a crosslinking agent, a water-resistant agent, or an additive can be added to the adhesive. These are not particularly limited and can be selected as appropriate.

[0103] A transparent protective layer or functional layer may be further provided on one or both sides of the polarizing plate on which the transparent protective film or the like is formed. Examples of transparent protective layers include hard coat layers made of acrylic, polysiloxane, or urethane materials. To further improve the unit transmittance, functional layers such as an antireflection layer (such as an anti-reflection layer or a low-reflection layer, or a combination thereof), an anti-glare layer (anti-glare layer), or an anti-fouling layer may be provided on the transparent protective film, transparent substrate, or transparent protective layer. The anti-reflection layer can be formed by vapor deposition or sputtering of a material such as silicon dioxide or titanium oxide, or by thinly coating a fluorine-based material.

[0104] An optical member may be laminated on one or both sides of the polarizing plate, or may be directly attached to the polarizing film. Examples of the optical member include a cover glass, a light diffusion film, and a retardation film.

[0105] For example, retardation films include retardation films made of transparent resins such as polycarbonate resins, and retardation films made of liquid crystal coatings. The polarizing plate and retardation film can be attached to each other via an adhesive or pressure-sensitive adhesive. A polarizing plate attached with a retardation film becomes an elliptical polarizing plate or a circular polarizing plate, and can be appropriately selected depending on the display device used to provide viewing angle compensation effects, interfacial reflection prevention effects, etc.

[0106] A support may be provided on one or both sides of the polarizing plate of the present invention, and the polarizing plate may be used as a support-attached polarizing plate. The support preferably has a flat surface for attaching the polarizing plate, and is preferably a transparent substrate because it is used for optical purposes. Transparent substrates are broadly divided into inorganic substrates and organic substrates, and examples thereof include inorganic substrates such as soda glass, borosilicate glass, quartz substrates, sapphire substrates, and spinel substrates, and organic substrates such as acrylic, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, and cycloolefin polymers.

[0107] In order to bond the polarizing plate to an optical member or a support, an adhesive layer may be formed on one or both sides of the polarizing plate. The adhesive layer formed can be an adhesive or a pressure-sensitive adhesive, but pressure-sensitive adhesives such as acrylic resin, polyester resin, and polyurethane resin are preferably used. The pressure-sensitive adhesive used is not limited to these and can be selected appropriately depending on the application and the member.

[0108] The polarizing plate of the present invention may be either a neutral gray polarizing plate or a color polarizing plate depending on the intended use. In addition, these polarizing plates have excellent polarizing performance and are further prevented from discoloring or from deteriorating in polarizing performance even under high-temperature and high-humidity conditions, and are therefore suitable for in-vehicle or outdoor displays.

[0109] <Display Device> The display device of the present invention includes the polarizing film or polarizing plate of the present invention. Examples of the display device include known liquid crystal display devices, projectors, and organic electronics display devices, and are applicable to, but are not limited to, displays for calculators, clocks, laptops, LCD televisions, car navigation systems, and indoor and outdoor measuring instruments and displays. In particular, the present invention is suitable for use in various displays requiring high polarization performance and durability, such as in-vehicle displays or outdoor displays (e.g., displays for industrial instruments or wearable applications). The dye-based polarizing film or dye-based polarizing plate included in the display device is preferably neutral gray.

[0110] For example, in the case of a liquid crystal display device, a dye-based polarizer is disposed on either the entrance side or the exit side or both of the liquid crystal cell. The dye-based polarizer may or may not be in contact with the liquid crystal cell, but from the viewpoint of durability, it is preferable that it is not in contact. When the dye-based polarizer is in contact with the liquid crystal cell on the exit side of the liquid crystal cell, the liquid crystal cell can be used as a support for the dye-based polarizer. When the dye-based polarizer is not in contact with the liquid crystal cell, it is preferable to use a dye-based polarizer provided with a support other than the liquid crystal cell. Furthermore, from the viewpoint of durability, it is preferable to dispose a dye-based polarizer on both the entrance side and the exit side of the liquid crystal cell, and further it is preferable to dispose the polarizer surface of the dye-based polarizer on the liquid crystal cell side and the support surface on the light source side. Note that the entrance side of the liquid crystal cell refers to the light source side, and the opposite side is called the exit side.

[0111] The liquid crystal display device can be driven by any suitable method known in the art. For example, an active matrix drive type is preferred, in which a liquid crystal is sealed between a transparent substrate on which electrodes and thin film transistors are formed and a transparent substrate on which a counter electrode is formed. Light emitted from a light source such as a cold cathode tube lamp or a white LED passes through a dye-based polarizer, then a liquid crystal cell, a color filter, and another dye-based polarizer, before being projected onto a display screen.

[0112] The present invention will be described in more detail below with reference to examples, but these are merely illustrative and do not limit the present invention in any way. Percentages and parts in the examples are by weight unless otherwise specified.

[0113] Example 1 (Step 1) A tetrakisazo compound represented by formula (4) was obtained according to the method described in International Publication No. WO 2012 / 108169. Details are described below. 25.3 parts by weight of 4-aminobenzene-1,3-disulfonic acid was added to 500 parts by weight of water, and the mixture was cooled to 10°C or below. 31.3 parts by weight of a 35 wt% aqueous hydrochloric acid solution was then added, followed by 6.9 parts by weight of sodium nitrite. The mixture was stirred at 5 to 10°C for 1 hour to effect diazotization. 10.7 parts by weight of 3-methylaniline dissolved in a dilute aqueous hydrochloric acid solution as a primary coupler (coupling component) was then added, and while stirring at 10 to 30°C, sodium carbonate was added to adjust the pH to 3. The mixture was further stirred to complete the coupling reaction, and the mixture was filtered to obtain 29.7 parts by weight of a monoazoamino compound represented by formula (1A).

[0114] Next, the obtained monoazoamino compound of formula (1A) was added to 400 parts by weight of water and dissolved with sodium hydroxide, and 25.0 parts by weight of a 35 wt % aqueous hydrochloric acid solution was added at 10 to 30° C., followed by 5.5 parts by weight of sodium nitrite, and the mixture was stirred at 20 to 30° C. for 1 hour to perform diazotization. To this was added 8.6 parts by weight of 3-methylaniline dissolved in a dilute aqueous hydrochloric acid solution as a secondary coupler, and sodium carbonate was added while stirring at 20 to 30° C. to adjust the pH to 3. The mixture was further stirred to cause a coupling reaction, and then filtered to obtain 31.3 parts by weight of a disazoamino compound represented by formula (2A).

[0115] Next, the obtained disazoamino compound of formula (2A) was added to 250 parts by weight of water and dissolved with sodium hydroxide, and 20.0 parts by weight of a 35 wt % aqueous hydrochloric acid solution was added at 20 to 30° C., followed by 4.4 parts by weight of sodium nitrite, and the mixture was stirred at 20 to 30° C. for 1 hour to perform diazotization. To this was added 9.8 parts by weight of 2,5-dimethoxyaniline dissolved in a dilute aqueous hydrochloric acid solution as a tertiary coupler, and sodium carbonate was added while stirring at 20 to 30° C. to adjust the pH to 3.5. The mixture was further stirred to complete the coupling reaction, and then filtered to obtain 32.6 parts by weight of a trisazoamino compound represented by formula (3A).

[0116] Next, the obtained trisazoamino compound of formula (3A) was added to 200 parts by weight of water and dissolved with sodium hydroxide, and then 16.0 parts by weight of a 35 wt % aqueous hydrochloric acid solution was added at 20 to 30°C, followed by 3.5 parts by weight of sodium nitrite, and the mixture was stirred at 20 to 30°C for 1 hour to diazotize, thereby obtaining a diazotized trisazoamino compound.

[0117] As a quaternary coupler, 17.6 parts by weight of 6-(4'-methoxyphenylamino)-1-naphthol-3-sulfonic acid was added to 50 parts by weight of water, and the solution was dissolved in a weak alkaline solution made with sodium carbonate to obtain a quaternary coupler solution.

[0118] The diazotized trisazoamino compound obtained earlier was added to this quaternary coupler solution while maintaining the pH at 8 to 10, and the mixture was stirred to complete the coupling reaction. The mixture was then filtered to obtain 38.2 parts of the tetrakisazo compound represented by formula (4).

[0119] (Step 2) 38.2 parts of the tetrakis azo compound obtained in Step 1 was added to 900 parts of water and stirred to form a suspension. 28.4 parts of N-methylethanolamine and 11.3 parts of copper sulfate pentahydrate were added thereto and reacted at 90 to 98°C for 10 hours to complete the copperation reaction. After salting out with sodium chloride, the mixture was filtered and dried to obtain 8.7 parts of a coppered tetrakis azo compound represented by formula (5) (Example Compound 1-4).

[0120] Example 2 (Step 1) In accordance with the method described in WO 2012 / 108173, 39.6 parts by weight of the tetrakisazo compound represented by formula (6) was obtained in the same manner as in Step 1 of Example 1, except that the reaction starting material was changed from 25.3 parts by weight of 4-aminobenzene-1,3-disulfonic acid to 38.3 parts by weight of 7-aminonaphthalene-1,3,6-trisulfonic acid.

[0121] (Step 2) 6.7 parts of a coppered tetrakisazo compound represented by formula (7) (Example Compound 1-24) was obtained in the same manner as in Step 2 of Example 1, except that the tetrakisazo compound obtained in Step 1 of Example 2 was used.

[0122] Example 3 (Step 1) 33.2 parts by weight of a tetrakisazo compound represented by formula (101) was obtained in the same manner as in Example 1, except that 9.8 parts by weight of 2,5-dimethoxyaniline as a tertiary coupler was changed to 8.8 parts by weight of 2-methoxy-5-methylaniline.

[0123] (Step 2) 8.5 parts of a coppered tetrakisazo compound represented by formula (102) was obtained in the same manner as in step 2 of Example 1, except that the tetrakisazo compound obtained in step 1 of Example 3 was used.

[0124] Example 4 (Step 1) 31.9 parts by weight of a tetrakisazo compound represented by formula (103) was obtained in the same manner as in Example 3, except that 17.6 parts by weight of 6-(4'-methoxyphenylamino)-1-naphthol-3-sulfonic acid as the quaternary coupler was changed to 16.1 parts by weight of 6-phenylamino-1-naphthol-3-sulfonic acid.

[0125] (Step 2) 8.3 parts of a coppered tetrakisazo compound represented by formula (104) was obtained in the same manner as in step 2 of Example 1, except that the tetrakisazo compound obtained in step 1 of Example 4 was used.

[0126] Example 5 (Step 1) 28.5 parts by weight of a tetrakisazo compound represented by formula (105) was obtained in the same manner as in Example 3, except that 17.6 parts by weight of 6-(4'-methoxyphenylamino)-1-naphthol-3-sulfonic acid as the quaternary coupler was changed to 12.2 parts by weight of 6-amino-1-naphthol-3-sulfonic acid.

[0127] (Step 2) 7.7 parts of a coppered tetrakisazo compound represented by formula (106) was obtained in the same manner as in step 2 of Example 1, except that the tetrakisazo compound obtained in step 1 of Example 5 was used.

[0128] Comparative Example 1 9.3 parts of a coppered tetrakisazo compound represented by formula (8) was obtained in the same manner as in Example 1, except that 23.1 parts by weight of monoethanolamine was used instead of 28.4 parts by weight of N-methylethanolamine used in step 2 of Example 1.

[0129] Comparative Example 2 With reference to Patent Document 3, a compound was synthesized in which monoethanolamine was coordinated to the compound described in Example 1, Compound Example 1 of Patent Document 3. The structure is shown in formula (9).

[0130] Comparative Example 3 With reference to the method described in Patent Document 3, a compound was synthesized in which monoethanolamine was coordinated to the compound described in Compound Example 13 of Patent Document 3. The structure is shown in formula (10).

[0131] Comparative Example 4 7.7 parts of a coppered tetrakisazo compound represented by formula (11) was obtained in the same manner as in Example 2, except that 23.1 parts by weight of monoethanolamine was used instead of 28.4 parts by weight of N-methylethanolamine used in step 2 of Example 2.

[0132] (Examples 1 to 5 and Comparative Examples 1 to 4: Preparation of Polarizing Film) A 75 μm thick polyvinyl alcohol film was immersed for 4 minutes in a 45° C. aqueous solution (dye bath) containing 0.03% of each of the azo compounds obtained in Examples 1 to 5 and Comparative Examples 1 to 4 and 0.1% sodium sulfate. This film was stretched 5 times at 55° C. in a 3% aqueous boric acid solution, and then washed with water and dried while maintaining the tension to prepare a polarizing film. The prepared polarizing films were used as measurement samples for Examples 1 and 2 and Comparative Examples 1 to 4.

[0133] The polarizing films obtained in Examples 1 to 5 and Comparative Examples 1 to 4 were evaluated as follows. (a) Polarized Parallel Transmittance (Ky) and Polarized Crossed Transmittance (Kz) The maximum absorption wavelength, polarized parallel transmittance (Ky), and polarized crossed transmittance (Kz) of the polarizing film were measured using a spectrophotometer (UH-4150, manufactured by Hitachi High-Tech Science Corporation). Ky refers to the transmittance when the absorption axis of the absolute polarizer and the polarizing film are superimposed parallel to each other, and Kz refers to the transmittance when the absorption axis of the absolute polarizer and the polarizing film are superimposed perpendicular to each other. Ky and Kz were measured at wavelength intervals of 1 nm from 380 nm to 780 nm (or 720 nm, or 700 nm). (b) Single-Phase Transmittance (Ts) The single-ply transmittance (Ts) represents the spectral transmittance of a single polarizing film. From the measured Ky and Kz at the maximum absorption wavelength, the transmittance was calculated using the following formula (I): Ts(%) = (Ky+Kz) / 2 Formula (I)

[0134] (c) Degree of polarization (ρ) and dichroic ratio The degree of polarization (ρ) and dichroic ratio at the maximum absorption wavelength of each measurement sample were calculated using the following formulas (II) and (III): ρ(%) = [(Ky-Kz) / (Ky+Kz)]×100 (calculation formula (II)) Dichroic ratio = log(Kz / 100) / log(Ky / 100) (calculation formula (III))

[0135] Table 1 shows the values ​​obtained by measurement and calculation of the polarizing films of Example 1 and Comparative Example 1.

[0136] As shown in Table 1, Example 1 using N-methylethanolamine had a higher polarization degree and dichroic ratio than Comparative Example 1 using monoethanolamine adjusted to the same level of single transmittance.

[0137] Table 2 shows the values ​​obtained by measurement and calculation of the polarizing films of Example 1 and Comparative Examples 2 and 3.

[0138] As shown in Table 2, Example 1 has a higher dichroic ratio and a higher degree of polarization than Comparative Examples 2 and 3. In other words, Example 1 is a dichroic dye with better optical properties than known dichroic dyes capable of handling the long wavelength region, such as Comparative Examples 2 and 3 described in Patent Document 3.

[0139] As shown in Table 3, Examples 3 to 5 have higher dichroic ratios and polarization degrees than Comparative Examples 2 and 3. In other words, it was demonstrated that Examples 3 to 5 are dichroic dyes with better optical properties than known dichroic dyes capable of handling the long wavelength region, such as Comparative Examples 2 and 3 described in Patent Document 3.

[0140] Table 4 shows the values ​​of ρ and dichroic ratio at 700 nm and 720 nm obtained by measurement and calculation of the polarizing films of Example 1 and Comparative Examples 1 to 3.

[0141] As shown in Table 4, Example 1 has a polarization degree of 99.0% or more at 700 nm and 720 nm, and also a high dichroic ratio of 45 or more, demonstrating higher polarization performance than Comparative Examples 1 to 3. Comparative Examples 1 and 3 have λmax similar to that of Example 1, but show lower polarization degrees and dichroic ratios at 700 nm and 720 nm, indicating that their polarization performance in the long wavelength region is lower than that of Example 1. Thus, Example 1 exhibits excellent optical properties even in the long wavelength region of 700 nm or more, demonstrating that it is a dichroic dye capable of producing a polarizing film with excellent optical properties over a wide absorption band.

[0142] Table 5 shows the values ​​obtained by measurement and calculation of the polarizing films of Example 2 and Comparative Example 4.

[0143]

[0144] As shown in Table 5, Example 2, which used N-methylethanolamine, had a polarization degree of 99.0% or more, which was higher than that of Comparative Example 4, which used monoethanolamine. In other words, even in Example 2, which has a different chemical structural formula from Example 1, it was shown that the difference in the type of amine coordinated to copper affects the polarization performance.

[0145] Example 6 Dye-Based Polarizing Plate A dye-based polarizing plate was prepared by bonding triacetyl cellulose films via a polyvinyl alcohol adhesive to both sides of the polarizing film obtained in Example 1. One side of the obtained polarizing plate was attached to glass using a pressure-sensitive adhesive, and this was used as an observation sample for Example 6.

[0146] Comparative Example 5 Iodine-Based Polarizing Plate As a general iodine-based polarizing plate, one side of an iodine-based polarizing plate (product name: SKN-18243P) manufactured by Nippon Kayaku Co., Ltd. was attached to glass using an adhesive, and used as an observation sample in Comparative Example 5.

[0147] The polarizing plates of Example 6 and Comparative Example 5 were visually observed for hue change after 500 hours under heat-resistant conditions at an ambient temperature of 105°C or 500 hours under high-temperature, high-humidity conditions at an ambient temperature of 80°C and a relative humidity of 90%. The observations were conducted by five experts, and the consensus of the observation results was determined. The results are shown in Table 6 (no or almost no hue change: ◯, slight hue change: △, significant hue change: ×).

[0148]

[0149] The results in Table 6 show that the dye-based polarizing plate of Example 6 showed almost no change in hue even under high temperature and high temperature / high humidity conditions. On the other hand, a very large change in hue was observed in the iodine-based polarizing plate of Comparative Example 5. In other words, the dye-based polarizing plate of the present invention has high environmental resistance and is suitable for use in display devices used in harsh environments.

[0150] A polarizing film or polarizing plate prepared using the azo compound of the present invention may be provided with a protective layer or functional layer and a transparent support such as glass, quartz, or sapphire, as necessary, and is used in liquid crystal projectors, calculators, clocks, notebook computers, liquid crystal televisions, polarized lenses, polarized glasses, car navigation systems, and indoor and outdoor measuring instruments and displays, etc. In particular, the polarizing film or polarizing plate of the present invention can be suitably used in display devices such as reflective liquid crystal display devices, semi-transmissive liquid crystal display devices, and organic electroluminescence displays (commonly known as OLEDs) other than liquid crystal display devices.

Claims

1. An azo compound represented by the following formula (0) or a salt thereof: (In formula (0), X represents an amino group which may have a substituent, or a phenylamino group which may have a substituent; Q and R １ ~R ５ each independently represents an arbitrary substituent, n represents an integer of 1 to 3, and s, t, u, and v each independently represent an integer of 0 to 2.

2. In formula (0), Q is a C group having a hydrogen atom, a carboxy group, or a sulfo group. １ -C ４ is an alkoxy group, R １ ~R ５ are each independently a hydrogen atom, C １ -C ４ Alkyl group, C １ -C ４ C having an alkoxy group or a sulfo group １ -C ４ an alkoxy group, X is unsubstituted or C １ ~C ４ C having an alkoxy group or a sulfo group １ -C ４ Alkoxy group, C １ ~C ４ a phenylamino group having one or two substituents selected from the group consisting of an alkyl group, a carboxy group, a hydroxy group, a sulfo group, and an amino group, or an unsubstituted or one or two C １ ~C ４ The azo compound or a salt thereof according to claim 1 , wherein the azo compound or a salt thereof is an amino group having an alkyl group.

3. The azo compound or salt thereof according to claim 1, wherein the azo compound represented by formula (0) or a salt thereof is represented by the following formula (2) or a salt thereof: (In formula (2), R １ ~R ４ are each independently a hydrogen atom, C １ -C ４ Alkyl group, C １ -C ４ C having an alkoxy group or a sulfo group １ -C ４ represents an alkoxy group, and n represents an integer of 1 to 3.

4. The azo compound or salt thereof according to claim 1, wherein the azo compound represented by formula (0) or a salt thereof is represented by the following formula (3) or a salt thereof: (In formula (3), n represents an integer of 1 to 3.) 5. A polarizing film containing a substrate, characterized in that the azo compound or salt thereof according to any one of claims 1 to 4 is contained in the substrate.

6. A polarizing plate comprising a transparent protective film provided on one side and both sides of the polarizing film according to claim 5.

7. A display device comprising the polarizing plate according to claim 6.

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