Dye-based polarizing film, and polarizing plate and display device containing the same

Abstract

A polarizing film containing a substrate, wherein the polarizing film is characterized in that the substrate contains an azo compound represented by formula (1) or a salt thereof (compound A), and an azo compound represented by formula (2) or a salt thereof (compound B). (In formula (1), X1 represents an amino group which may have a substituent, a phenylamino group which may have a substituent, a naphthylamino group which may have a substituent, a benzoylamino group which may have a substituent, or a naphthotriazole group which may have a substituent. Q1 and R1 to R4 each independently represent an optional substituent, and m represents an integer of 1 to 3.) (In formula (2), X2 represents an amino group which may have a substituent, a phenylamino group which may have a substituent, a naphthylamino group which may have a substituent, a benzoylamino group which may have a substituent, or a naphthotriazole group which may have a substituent. Q2, Q3, and R5-R8 each independently represent an optional substituent. A represents a sulfonyl group or a carboxyl group, and n represents an integer of 0 to 3.)

Description

Dye-based polarizing film, and polarizing plate and display device containing the same.

[0001] The present invention relates to a dye-based polarizing film having high contrast, and to a polarizing plate and display device containing the same (hereinafter also referred to as "polarizing film, etc.").

[0002] In recent years, display devices have predominantly utilized LED backlights as their light source, and their photometric colorimetric measurement is defined in JIS Z8724:2015. This standard specifies that the wavelength range for color matching functions is 360 nm to 830 nm, and that when performing spectral measurements of LED light sources for colorimetric purposes, the wavelength range may also be 380 nm to 780 nm.

[0003] Furthermore, polarizing films and polarizing plates in organic electroluminescent (EL) display devices (hereinafter referred to as OLEDs) are used to provide an anti-reflective function against the phenomenon of external light being reflected (internal reflection) by the metal electrodes and other components that constitute the OLED. In this case, an optical laminate, which is generally made by laminating a phase difference plate such as a λ / 4 film and a polarizing film, is bonded to the surface of the OLED so that the polarizing film is on the viewing side, thereby exhibiting an anti-reflective function. However, even polarizing films used in this way to suppress internal reflection do not have high optical properties in the wavelength range up to 780 nm, so reflected light may appear colored, which significantly deteriorates the display quality in bright indoor and outdoor environments.

[0004] As for the formulation of general dichroic dyes, various dye-based polarizers with different characteristics have been developed, as exemplified by Patent Documents 1-5, 8, and 9. However, in the applications for polarizers for display devices reported to date, the wavelength range for optical measurement is either 400 nm to 700 nm, or the wavelength range for optical measurement itself is not described, and the optical properties above 700 nm have not been discussed. In fact, the dye-based polarizer described in Patent Document 2 has low absorption performance above 700 nm, so when the absorption axes of the two polarizers are placed perpendicular to each other, a phenomenon occurs where the backlight appears to leak through (hereinafter referred to as light leakage).

[0005] In recent years, tetrakiscopper dyes have been developed. Patent documents 1 to 8 describe dichroic dyes with good polarization properties and examples of formulations using them. For example, Example 8 of Patent Document 1 discloses a formulation containing a tetrakisazo compound and a tetrakisazocopper compound. However, the contrast described is low, and no combination of tetrakisazocopper compounds has been reported that provides sufficient polarization performance in the 380-780 nm range.

[0006] International Publication No. 2017 / 135392, International Publication No. 2016 / 186183, Japanese Patent Publication No. 2021-002043, Japanese Patent Publication No. 2017-090903, International Publication No. 2020 / 050333, International Publication No. 2012 / 108169, International Publication No. 2012 / 108173, International Publication No. 2017 / 135391, International Publication No. 2019 / 117131, International Publication No. 2022 / 071201, International Publication No. 2022 / 071204

[0007] The object of the present invention is to provide a polarizing film having high contrast, as well as a polarizing plate and a display device containing the same.

[0008] As a result of diligent research to solve the aforementioned problems, the present inventors have discovered that by combining two types of azo compounds having a specific structure as dichroic dyes, namely a predetermined trisazo compound and a tetrakisazo copper compound, a polarizing film with high contrast, as well as a polarizing plate and display device containing the same, can be obtained, thus completing the present invention.

[0009] In other words, the present invention relates to, but is not limited to, the following [1] to [9]. [1] A polarizing film containing a substrate, wherein the substrate contains an azo compound or a salt thereof represented by the following formula (1) (compound A) and an azo compound or a salt thereof represented by the following formula (2) (compound B). (In formula (1), X １ Q represents an optionally substituted amino group, or an optionally substituted phenylamino group, an optionally substituted naphthylamino group, an optionally substituted benzoylamino group, or an optionally substituted naphthotriazole group. １ and R１ to R ４ each independently represents an arbitrary substituent, and m represents an integer of 1 to 3. (In formula (2), X ２ represents an amino group which may have a substituent, or a phenylamino group which may have a substituent, a naphthylamino group which may have a substituent, a benzoylamino group which may have a substituent, a naphthotriazole group which may have a substituent, Q ２ , Q ３ , and R ５ to R ８ each independently represents an arbitrary substituent, A represents a sulfo group or a carboxy group, and n represents an integer of 0 to 3. ) [2] In formula (1), Q １ is a hydrogen atom, a C １ to C ４ alkoxy group having a sulfo group, or a carboxy group, and X １ is an unsubstituted amino group; an amino group having one or two C １ to C ４ alkyl groups; an unsubstituted phenylamino group; or a phenylamino group having one or two substituents selected from the group consisting of a C １ to C ４ alkoxy group, a C １ to C[[ID=第34]] ４ alkoxy group having a sulfo group, a C １ to C ４ alkyl group, a carboxy group, a hydroxy group, a sulfo group, and an amino group, and in formula (2), Q ２ and Q ３ each independently is a hydrogen atom, a C[[ID=第44]] １ to C ４ alkoxy group having a sulfo group, or a carboxy group, and X ２ is an unsubstituted amino group; an amino group having one or two C １ to C ４ alkyl groups; an unsubstituted phenylamino group; or a phenylamino group having one or two substituents selected from the group consisting of a C １ to C ４ alkoxy group, a C[[ID=5第58]] １ to C ４ alkoxy group having a sulfo group, a C １ to C ４ It should be noted that there may be some inaccuracies in the original text numbering (such as "第34", "第44", "第58" etc. which seem to be incorrect numbering in the original). This translation is done based on the best understanding of the text.The polarizing film according to [1], wherein the phenylamino group has one or two substituents selected from the group consisting of alkyl groups, carboxyl groups, hydroxyl groups, sulfo groups, and amino groups. [3] The polarizing film according to [1], wherein the compound represented by formula (1) is represented by the following formula (3), and the compound represented by formula (2) is represented by the following formula (4). (In formula (3), R １ ~R ４ Each of these independently represents an arbitrary substituent, and m represents an integer from 1 to 3. (In formula (4), R ５ ~R ８ Each of these independently represents an arbitrary substituent, R ９ R represents a hydrogen or methoxy group, A represents a sulfo group or carboxyl group, and n represents an integer from 0 to 3.) [4] In formula (3), R １ ~R ４ Each of them independently forms a hydrogen atom, C １ ~C ４ alkyl group, C １ ~C ４ C having an alkoxy group and a sulfo group １ ~C ４ It is an alkoxy group, and in formula (4), R ５ ~R ８ Each of them independently forms a hydrogen atom, C １ ~C ４ alkyl group, C １ ~C ４ C having an alkoxy group and a sulfo group １ ~C ４A polarizing film according to [3], wherein the polarizing film is an alkoxy group, A is a sulfo group or a carboxyl group, and n is an integer of 1 or 2. [5] A polarizing film according to any one of [1] to [4], comprising one or more dichroic dyes other than the azo compounds or salts thereof described in any one of [1] to [4]. [6] A polarizing film according to any one of [1] to [5], wherein the single-layer transmittance (Ys) after luminous efficiency correction in the range of 380 nm to 780 nm is 39% or more, and the orthogonal transmittance (Tc) at 730 nm is 1% or less. [7] A polarizing film according to any one of [1] to [6], characterized in that the substrate described in [1] is a film made of a polyvinyl alcohol-based resin. [8] A polarizing plate comprising a transparent protective film provided on one or both sides of the polarizing film according to any one of [1] to [7]. [9] A display device comprising the polarizing plate described in [8].

[0010] According to the present invention, it is possible to provide a polarizing film having high contrast.

[0011] In this specification and in the claims, unless it clearly refers to a free form, “azo compound or salt thereof” may also be simply referred to as “azo compound.” In this specification and in the claims, since “substituents” may include hydrogen atoms, hydrogen atoms may also be described as “substituents” for convenience. “May have substituents” means that it also includes cases without substituents. For example, “a phenyl group that may have substituents” includes an unsubstituted, simple phenyl group and a phenyl group with substituents.

[0012] Furthermore, in this specification and the claims, the term "polarizing plate" includes linear polarizing plates, circular polarizing plates, and elliptical polarizing plates.

[0013] The polarizing film of the present invention is characterized in that it contains a substrate, the substrate contains an azo compound or a salt thereof represented by the following formula (1) (compound A), and an azo compound or a salt thereof represented by the following formula (2) (compound B). Compound A: (In formula (1), X １Q represents an optionally substituted amino group, or an optionally substituted phenylamino group, an optionally substituted naphthylamino group, an optionally substituted benzoylamino group, or an optionally substituted naphthotriazole group. １ and R １ ~R ４ Each of these independently represents an arbitrary substituent, and m represents an integer from 1 to 3. ) Compound B: (In formula (2), X ２ Q represents an optionally substituted amino group, or an optionally substituted phenylamino group, an optionally substituted naphthylamino group, an optionally substituted benzoylamino group, or an optionally substituted naphthotriazole group. ２ Q ３ , and R ５ ~R ８ Each of the following independently represents an arbitrary substituent: A represents a sulfo group or a carboxyl group, and n represents an integer from 0 to 3.

[0014] In formulas (1) and (2), the ring structures drawn with solid and dashed lines represent a phenyl (phenylene) group or a naphthyl (naphthylene) group.

[0015] In the above formulas (1) and (2), X １ and X ２ Each of these represents an optionally substituted amino group, an optionally substituted phenylamino group, an optionally substituted naphthylamino group, an optionally substituted benzoylamino group, or an optionally substituted naphthotriazole group, preferably an optionally substituted phenylamino group, and Q １ Q ２ Q ３ , and R １ ~R ８ Each of these independently represents an arbitrary substituent. The substituents that may be present as described above, and Q １ Q ２ Q ３ , and R １ ~R ８Any substituents shown by include, for example, a phenyl group, a diazenyl group, a heterocyclic amino group, a fused 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 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 hydroxyl group (-OH), a cyano group (-CN), a nitro group (-NO) ２ ), mercapto group (-SH), halogen atom, carboxyl group (-CO ２ H), sulfo group (-SO ３ H), amino group (-NH ２ Examples include hydrogen atoms, etc.

[0016] The above-mentioned heterocyclic amino groups include heterocyclic amino groups of five or six members containing one to three heteroatoms selected from the group consisting of nitrogen, oxygen, and sulfur atoms. Specific examples of such heterocyclic amino groups include, for example, five-membered heteroalicyclic amino groups such as pyrrolidinylamino, tetrahydrofurylamino, tetrahydrothiophen-2-ylamino, and tetrahydrothiophen-3-ylamino; six-membered heteroalicyclic amino groups such as piperidinylamino, piperazinylamino, dioxan-2-ylamino, morpholinylamino, and thiomorpholinylamino; five-membered aromatic heterocyclic amino groups such as pyrroleamino, pyrazoleamino, imidazoleamino, triazoleamino, furylamino, thiophen-2-ylamino, thiophen-3-ylamino, oxazoleamino, and thiazoleamino; or six-membered aromatic heterocyclic amino groups such as pyridylamino, pyrazylamino, pyridadinylamino, and triazinylamino. The heterocyclic group preferably has an aromatic ring as its heterocyclic portion. Furthermore, the heteroatoms constituting the heterocyclic ring are preferably selected from nitrogen atoms and sulfur atoms.

[0017] Examples of the fused heterocyclic amino group mentioned above include a fused heterocyclic amino group of five or six members, in which one benzene ring is fused to a five or six-membered heterocyclic group containing one to three heteroatoms selected from the group consisting of nitrogen, oxygen, and sulfur atoms. Specific examples of such fused heterocyclic amino groups include, for example, fused heterocyclic amino groups in which the heterocyclic portion is a five-membered alicyclic ring, such as phthalanylamino; fused heterocyclic amino groups in which the heterocyclic portion is a six-membered alicyclic ring, such as benzopyranylamino; fused aromatic heterocyclic amino groups in which the heterocyclic portion is an aromatic five-membered ring, such as benzopyrroleamino, benzopyrazoleamino, benzimidazoleamino, benzotriazoleamino, benzofuranylamino, benzothiophen-2-ylamino, benzothiophen-3-ylamino, benzoxazoleamino, and benzothiazoleamino; or fused aromatic heterocyclic amino groups in which the heterocyclic portion is an aromatic six-membered ring, such as quinolinylamino, synnolinylamino, phthalazinylamino, quinazolinylamino, and quinoxalinylamino. It is preferable that the heterocyclic portion of the heterocyclic group is an aromatic ring. Furthermore, it is preferable that the heteroatoms constituting the heterocycle be selected from nitrogen atoms and sulfur atoms.

[0018] The alkyl group mentioned above is a linear, branched, or cyclic alkyl group, preferably C １ ~C １０ Alkyl groups are examples. C １ ~C １０ Specific examples of alkyl groups include linear C molecules 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 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 Alkyl groups; or cyclic C such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, etc. ３ ~C７ An alkyl group can be mentioned. Among these, a linear or branched alkyl group is preferable, and a linear C １ to C ４ alkyl group is more preferable.

[0019] As the above alkoxy group, a linear, branched or cyclic alkoxy group, preferably a C １ to C １０ alkoxy group can be mentioned. C １ to C １０ Specific examples of the C １ to C １０ alkoxy group include, for example, linear C ３ to C １０ alkoxy groups such as methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy; branched C ３ to C ７ alkoxy groups such as isopropoxy, isobutoxy, sec-butoxy, t-butoxy, isoamyloxy, t-amyloxy, isohexyloxy, t-hexyloxy, isoheptyloxy, t-heptyloxy, isooctyloxy, t-octyloxy, 2-ethylhexyloxy, isononyloxy, isodecyloxy; or cyclic C １ to C ４ alkoxy groups such as cyclopropoxy, cyclobutoxy, cyclopentoxy, cyclohexyloxy, cycloheptyloxy. Among these, a linear or branched alkoxy group is preferable, and a linear C

[0020] As the alkoxy group having the above sulfo group, a linear C １ to C<00​​​​​​​These are aryloxy groups, and specific examples include phenoxy, naphthyloxy, and biphenyloxy.

[0022] The alkylcarbonylamino group mentioned above is a linear, branched, or cyclic alkylcarbonylamino group, preferably C １ ~C １０ Examples include alkylcarbonylamino groups. １ ~C １０ Specific examples of alkylcarbonylamino groups include linear carbonylamino 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-chain carbons such as isopropylcarbonylamino, isobutylcarbonylamino, sec-butylcarbonylamino, t-butylcarbonylamino, isoamylcarbonylamino, t-amylcarbonylamino, isohexylcarbonylamino, t-hexylcarbonylamino, isoheptylcarbonylamino, t-heptylcarbonylamino, isooctylcarbonylamino, t-octylcarbonylamino, 2-ethylhexylcarbonylamino, isononylcarbonylamino, isodecylcarbonylamino, etc. ３ ~C １０ Alkylcarbonylamino group; or cyclic C such as cyclopropylcarbonylamino, cyclobutylcarbonylamino, cyclopentylcarbonylamino, cyclohexylcarbonylamino, cycloheptylcarbonylamino, etc. ３ ~C ７ Examples include alkylcarbonylamino groups. Among these, linear or branched alkylcarbonylamino groups are preferred, and linear alkylcarbonylamino groups are more preferred.

[0023] The above arylcarbonylamino group is preferably C ６ ~C １２These are arylcarbonylamino groups, and specific examples include phenylcarbonylamino (benzoylamino), naphthylcarbonylamino, and biphenylcarbonylamino.

[0024] The alkylcarbonyloxy group mentioned above is a linear, branched, or cyclic alkylcarbonyloxy group, preferably C １ ~C １０ Examples include alkylcarbonyloxy groups. １ ~C １０ Specific examples of alkylcarbonyloxy groups include linear carbonyloxy 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; branched-chain carbonyloxy groups such as isopropylcarbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, t-butylcarbonyloxy, isoamylcarbonyloxy, t-amylcarbonyloxy, isohexylcarbonyloxy, t-hexylcarbonyloxy, isoheptylcarbonyloxy, t-heptylcarbonyloxy, isooctylcarbonyloxy, t-octylcarbonyloxy, 2-ethylhexylcarbonyloxy, isononylcarbonyloxy, isodecylcarbonyloxy, etc. ３ ~C １０ Alkylcarbonyloxy group; or cyclic C such as cyclopropylcarbonyloxy, cyclobutylcarbonyloxy, cyclopentylcarbonyloxy, cyclohexylcarbonyloxy, cycloheptylcarbonyloxy. ３ ~C ７ Examples include alkylcarbonyloxy groups. Among these, linear or branched alkylcarbonyloxy groups are preferred, and linear alkylcarbonyloxy groups are more preferred.

[0025] The above arylcarbonyloxy group is preferably C ６ ~C１２ These are arylcarbonyloxy groups, and specific examples include phenylcarbonyloxy, naphthylcarbonyloxy, and biphenylcarbonyloxy.

[0026] The alkylcarbonyl group mentioned above is a linear, branched, or cyclic alkylcarbonyl group, preferably C １ ~C １０ Examples include alkylcarbonyl groups. １ ~C １０ Specific examples of alkylcarbonyl groups include linear carbonyl 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 Alkyl carbonyl groups; branched C groups such as isopropyl carbonyl, isobutyl carbonyl, sec-butyl carbonyl, t-butyl carbonyl, isoamyl carbonyl, t-amyl carbonyl, isohexyl carbonyl, t-hexyl carbonyl, isoheptyl carbonyl, t-heptyl carbonyl, isooctyl carbonyl, t-octyl carbonyl, 2-ethylhexyl carbonyl, isononyl carbonyl, and isodecyl carbonyl. ３ ~C １０ Alkyl carbonyl group; or cyclic carbon such as cyclopropyl carbonyl, cyclobutyl carbonyl, cyclopentyl carbonyl, cyclohexyl carbonyl, cycloheptyl carbonyl, etc. ３ ~C ７ Examples include alkylcarbonyl groups. Among these, linear or branched alkylcarbonyl groups are preferred, and linear alkylcarbonyl groups are more preferred.

[0027] The above arylcarbonyl group is preferably C ６ ~C １２ These are arylcarbonyl groups, and specific examples include phenylcarbonyl (benzoyl), naphthylcarbonyl, and biphenylcarbonyl.

[0028] Examples of the alkylcarbamoyl groups mentioned above include linear, branched, or cyclic monoalkylcarbamoyl groups or dialkylcarbamoyl groups.

[0029] The monoalkylcarbamoyl group is preferably monoC １ ~C １０ These are alkylcarbamoyl groups, and specific examples include linear mono-C 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 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 Alkylcarbamoyl group; or cyclic mono-C such as cyclopropylcarbamoyl, cyclobutylcarbamoyl, cyclopentylcarbamoyl, cyclohexylcarbamoyl, cycloheptylcarbamoyl, etc. ３ ~C ７ Examples include alkylcarbamoyl groups. Among these, linear or branched monoalkylcarbamoyl groups are preferred, and linear monoalkylcarbamoyl groups are more preferred.

[0030] The dialkylcarbamoyl group is preferably diC １ ~C １０These are alkylcarbamoyl groups, and specific examples include linear diC 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 group; branched-chain diC2, 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, diisodecylcarbamoyl, etc. ３ ~C １０ Alkylcarbamoyl group; or a cyclic diC having two rings, such as dicyclopropylcarbamoyl, dicyclobutylcarbamoyl, dicyclopentylcarbamoyl, dicyclohexylcarbamoyl, or dicycloheptylcarbamoyl. ３ ~C ７ Examples include alkylcarbamoyl groups. Among these, linear or branched dialkylcarbamoyl groups are preferred, and linear dialkylcarbamoyl groups are more preferred.

[0031] Examples of the arylcarbamoyl group mentioned above include a monoarylcarbamoyl group or a diarylcarbamoyl group.

[0032] The monoarylcarbamoyl group is preferably monoC ６ ~C １２ These are arylcarbamoyl groups, and specific examples include phenylcarbamoyl, naphthylcarbamoyl, and biphenylcarbamoyl.

[0033] Preferably, the diarylcarbamoyl group is diC ６ ~C １２These are arylcarbamoyl groups, and specific examples include diphenylcarbamoyl, dinaphthylcarbamoyl, and di(biphenyl)carbamoyl.

[0034] The alkoxycarbonyl group mentioned above is a linear, branched, or cyclic alkoxycarbonyl group, preferably C １ ~C １０ An example is the alkoxycarbonyl group. １ ~C １０ Specific examples of alkoxycarbonyl groups include, for example, linear carbon atoms 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; branched C 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 Alkoxycarbonyl group; or cyclic C such as cyclopropoxycarbonyl, cyclobutoxycarbonyl, cyclopentoxycarbonyl, cyclohexyloxycarbonyl, and cycloheptoxycarbonyl. ３ ~C ７ Examples include alkoxycarbonyl groups. Among these, linear or branched alkoxycarbonyl groups are preferred, and linear alkoxycarbonyl groups are more preferred.

[0035] The above aryloxycarbonyl group is preferably C ６ ~C １２These are aryloxycarbonyl groups, and specific examples include phenoxycarbonyl, naphthyloxycarbonyl, and biphenyloxycarbonyl.

[0036] The alkylsulfonylamino group mentioned above is a linear, branched, or cyclic alkylsulfonylamino group, preferably C １ ~C １０ Examples include alkylsulfonylamino groups. １ ~C １０ Specific examples of alkylsulfonylamino groups include linear C 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 Alkylsulfonylamino groups; branched C groups such as isopropylsulfonylamino, isobutylsulfonylamino, sec-butylsulfonylamino, t-butylsulfonylamino, isoamylsulfonylamino, t-amylsulfonylamino, isohexylsulfonylamino, t-hexylsulfonylamino, isoheptylsulfonylamino, t-heptylsulfonylamino, isooctylsulfonylamino, t-octylsulfonylamino, 2-ethylhexylsulfonylamino, isononylsulfonylamino, and isodecylsulfonylamino. ３ ~C １０ Alkyl sulfonylamino group; or cyclic C such as cyclopropyl sulfonylamino, cyclobutyl sulfonylamino, cyclopentyl sulfonylamino, cyclohexyl sulfonylamino, cycloheptyl sulfonylamino, etc. ３ ~C ７ Examples include alkylsulfonylamino groups. Among these, linear or branched alkylsulfonylamino groups are preferred, and linear alkylsulfonylamino groups are more preferred.

[0037] The above arylsulfonylamino group is preferably C ６ ~C １２These are arylsulfonylamino groups, and specific examples include phenylsulfonylamino, toluenesulfonylamino, naphthylsulfonylamino, and biphenylsulfonylamino.

[0038] Examples of the alkylsulfamoyl groups mentioned above include linear, branched, or cyclic monoalkylsulfamoyl groups or dialkylsulfamoyl groups.

[0039] The monoalkylsulfamoyl group is preferably monoC １ ~C １０ These are alkylsulfamoyl groups, and specific examples include linear mono-C 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 Alkyl sulfamoyl groups; branched mono-C groups such as isopropyl sulfamoyl, isobutyl sulfamoyl, sec-butyl sulfamoyl, t-butyl sulfamoyl, isoamyl sulfamoyl, t-amyl sulfamoyl, isohexyl sulfamoyl, t-hexyl sulfamoyl, isoheptyl sulfamoyl, t-heptyl sulfamoyl, isooctyl sulfamoyl, t-octyl sulfamoyl, 2-ethylhexyl sulfamoyl, isononyl sulfamoyl, and isodecyl sulfamoyl. ３ ~C １０ Alkyl sulfamoyl group; or cyclic mono-C such as cyclopropyl sulfamoyl, cyclobutyl sulfamoyl, cyclopentyl sulfamoyl, cyclohexyl sulfamoyl, cycloheptyl sulfamoyl, etc. ３ ~C ７ Examples include alkylsulfamoyl groups. Among these, linear or branched monoalkylsulfamoyl groups are preferred, and linear monoalkylsulfamoyl groups are more preferred.

[0040] The dialkylsulfamoyl group is preferably diC １ ~C１０ These are alkylsulfamoyl groups, and specific examples include linear diC 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 group; branched C2C2 having two branched chains, such as diisopropyl sulfamoyl, diisobutyl sulfamoyl, di-sec-butyl sulfamoyl, di-t-butyl sulfamoyl, diisoamyl sulfamoyl, di-t-amyl sulfamoyl, diisohexyl sulfamoyl, di-t-hexyl sulfamoyl, diisoheptyl sulfamoyl, di-t-heptyl sulfamoyl, diisooctyl sulfamoyl, di-t-octyl sulfamoyl, di-(2-ethylhexyl) sulfamoyl, diisononyl sulfamoyl, diisodecyl sulfamoyl, etc. ３ ~C １０ Alkyl sulfamoyl group; or a cyclic diC having two rings, such as dicyclopropyl sulfamoyl, dicyclobutyl sulfamoyl, dicyclopentyl sulfamoyl, dicyclohexyl sulfamoyl, or dicycloheptyl sulfamoyl. ３ ~C ７ Examples include alkylsulfamoyl groups. Among these, linear or branched dialkylsulfamoyl groups are preferred, and linear dialkylsulfamoyl groups are more preferred.

[0041] Examples of the arylsulfamoyl group mentioned above include a monoarylsulfamoyl group or a diarylsulfamoyl group.

[0042] The monoarylsulfamoyl group is preferably monoC ６ ~C １２ These are arylsulfamoyl groups, and specific examples include phenylsulfamoyl, naphthylsulfamoyl, and biphenylsulfamoyl.

[0043] The diarylsulfamoyl group is preferably diC ６ ~C １２ These are arylsulfamoyl groups, and specific examples include diphenylsulfamoyl, dinaphthylsulfamoyl, and di(biphenyl)sulfamoyl.

[0044] The alkylsulfonyl group mentioned above is a linear, branched, or cyclic alkylsulfonyl group, preferably C １ ~C １２ Examples include alkylsulfonyl groups. １ ~C １２ Specific examples of alkylsulfonyl groups include linear C 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; branched C 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-octyl sulfonyl, 2-ethylhexyl sulfonyl, isononyl sulfonyl, isodecyl sulfonyl, isoundecyl sulfonyl, t-undecyl sulfonyl, isododecyl sulfonyl, t-dodecyl sulfonyl, etc. ３ ~C １２ Alkyl sulfonyl group; or cyclic C such as cyclopropyl sulfonyl, cyclobutyl sulfonyl, cyclopentyl sulfonyl, cyclohexyl sulfonyl, cycloheptyl sulfonyl, etc. ３ ~C ７ Examples include alkylsulfonyl groups. Among these, linear or branched alkylsulfonyl groups are preferred, and linear alkylsulfonyl groups are more preferred.

[0045] The above aryl sulfonyl group is preferably C ６ ~C１２ These are arylsulfonyl groups, and specific examples include phenylsulfonyl, naphthylsulfonyl, and biphenylsulfonyl.

[0046] The alkylthio group mentioned above is a linear, branched, or cyclic alkylthio group, preferably C １ ~C １０ Examples include alkylthio groups. １ ~C １０ Specific examples of alkylthio groups include linear C 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; branched C groups such as isopropylthio, isobutylthio, sec-butylthio, t-butylthio, isoamylthio, t-amylthio, isohexylthio, t-hexylthio, isoheptylthio, t-heptylthio, isooctylthio, t-octylthio, 2-ethylhexylthio, isononylthio, isodecylthio, etc. ３ ~C １０ Alkylthio group; or cyclic C such as cyclopropylthio, cyclobutylthio, cyclopentylthio, cyclohexylthio, cycloheptylthio, etc. ３ ~C ７ Examples include alkylthio groups. Among these, linear or branched alkylthio groups are preferred, and linear alkylthio groups are more preferred.

[0047] The above arylthio group is preferably C ６ ~C １２ These are arylthio groups, and specific examples include phenylthio, naphthylthio, and biphenylthio.

[0048] Examples of the alkylureido groups mentioned above include linear, branched, or cyclic monoalkylureido groups or dialkylureido groups.

[0049] The monoalkylureide group is preferably monoC １ ~C １０These are alkylureide groups, and specific examples include linear mono-C groups such as methylureide, ethylureide, n-propylureide, n-butylureide, n-pentylureide, n-hexylureide, n-heptylureide, n-octylureide, n-nonylureide, and n-decylureide. １ ~C １０ Alkylureide groups; branched mono-C groups such as isopropylureide, isobutylureide, sec-butylureide, t-butylureide, isoamylureide, t-amylureide, isohexylureide, t-hexylureide, isoheptylureide, t-heptylureide, isooctylureide, t-octylureide, 2-ethylhexylureide, isononylureide, and isodecylureide. ３ ~C １０ Alkylureide group; or cyclic mono-C such as cyclopropylureide, cyclobutylureide, cyclopentylureide, cyclohexylureide, and cycloheptylureide. ３ ~C ７ Examples include alkylureido groups. Among these, linear or branched alkylureido groups are preferred, with linear alkylureido groups being a prime example.

[0050] The dialkylureide group is preferably diC １ ~C １０ These are alkylureide groups, and specific examples include linear diC groups such as dimethylureide, diethylureide, di-n-propylureide, di-n-butylureide, di-n-pentylureide, di-n-hexylureide, di-n-heptylureide, di-n-octylureide, di-n-nonylureide, and di-n-decylureide. １ ~C １０Alkylureide group; branched-chain diC with two branched chains, such as diisopropylureide, diisobutylureide, di-sec-butylureide, di-t-butylureide, diisoamylureide, di-t-amylureide, diisohexylureide, di-t-hexylureide, diisoheptylureide, di-t-heptylureide, diisooctylureide, di-t-octylureide, di-(2-ethylhexyl)ureide, diisononylureide, diisodecylureide, etc. ３ ~C １０ Alkylureide group; or a cyclic diC having two rings, such as dicyclopropylureide, dicyclobutylureide, dicyclopentylureide, dicyclohexylureide, or dicycloheptylureide. ３ ~C ７ Examples include alkylureido groups. Among these, linear or branched dialkylureido groups are preferred, and linear dialkylureido groups are more preferred.

[0051] Examples of the above-mentioned arylureide group include a monoarylureide group or a diarylureide group.

[0052] The monoarylureide group is preferably monoC ６ ~C １２ These are arylureide groups, and specific examples include phenylureide, naphthylureide, and biphenylureide.

[0053] The diaryluide group is preferably diC ６ ~C １２ These are aryl ureido groups, and specific examples include diphenylureido, dinaphthylureido, and di(biphenyl)ureido.

[0054] The alkoxycarbonylamino group mentioned above is a linear, branched, or cyclic alkoxycarbonylamino group, preferably C １ ~C １０ An example is the alkoxycarbonylamino group. １ ~C １０Specific examples of alkoxycarbonylamino groups include linear carbon atoms 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 group; branched chain C such as isopropoxycarbonylamino, isobutoxycarbonylamino, sec-butoxycarbonylamino, t-butoxycarbonylamino, isoamyloxycarbonylamino, t-amyloxycarbonylamino, isohexyloxycarbonylamino, t-hexyloxycarbonylamino, isoheptoxycarbonylamino, t-heptoxycarbonylamino, isooctyloxycarbonylamino, t-octyloxycarbonylamino, 2-ethylhexyloxycarbonylamino, isononyloxycarbonylamino, isodecyloxycarbonylamino, etc. ３ ~C １０ Alkoxycarbonylamino group; or cyclic C such as cyclopropoxycarbonylamino, cyclobutoxycarbonylamino, cyclopentoxycarbonylamino, cyclohexyloxycarbonylamino, cycloheptoxycarbonylamino, etc. ３ ~C ７ Examples include alkoxycarbonylamino groups. Among these, linear or branched alkoxycarbonylamino groups are preferred, and linear alkoxycarbonylamino groups are more preferred.

[0055] The above aryloxycarbonylamino group is preferably C ６ ~C １２ These are aryloxycarbonylamino groups, and specific examples include phenylcarbonylamino, naphthylcarbonylamino, and biphenylcarbonylamino.

[0056] Examples of the alkylamino groups mentioned above include linear, branched, or cyclic monoalkylamino groups or dialkylamino groups.

[0057] The monoalkylamino group is preferably monoC １ ~C １０ These are alkylamino groups, and specific examples include linear mono-C 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 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 cyclic mono-C such as cyclopropylamino, cyclobutylamino, cyclopentylamino, cyclohexylamino, cycloheptylamino, etc. ３ ~C ７ Examples include alkylamino groups. Among these, linear or branched monoalkylamino groups are preferred, and linear monoalkylamino groups are more preferred.

[0058] The dialkylamino group is preferably diC １ ~C １０ These are alkylamino groups, and specific examples include linear diC 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 group; branched C2 molecules 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 Alkylamino group; or a cyclic diC having two rings such as dicyclopropylamino, dicyclobutylamino, dicyclopentylamino, dicyclohexylamino, dicycloheptylamino, etc. ３ ~C ７ Examples include alkylamino groups. Among these, linear or branched dialkylamino groups are preferred, and linear dialkylamino groups are more preferred.

[0059] Examples of the arylamino group mentioned above include a monoarylamino group or a diarylamino group.

[0060] The monoarylamino group is preferably mono-C. ６ ~C １２ These are arylamino groups, and specific examples include phenylamino (anilino), naphthylamino, and biphenylamino.

[0061] The diarylamino group is preferably diC ６ ~C １２ These are arylamino groups, and specific examples include diphenylamino, dinaphthylamino, and di(biphenyl)amino.

[0062] Examples of the halogen atoms mentioned above include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, with fluorine atoms, chlorine atoms, or bromine atoms being preferred.

[0063] In one embodiment, X １ and X ２ Each of these independently comprises an amino group which may have substituents (e.g., unsubstituted, mono, or di-C). １ ~C ４The group may be a phenylamino group (having an alkyl group), a phenylamino group which may be substituted, a naphthylamino group which may be substituted (e.g., unsubstituted or having a hydroxyl group and / or a sulfo group), a benzoylamino group which may be substituted (e.g., unsubstituted or having an amino group), or a naphthotriazole group which may be substituted (e.g., unsubstituted or having a mono or di-sulfo group). Preferably, X １ and X ２ Each independently consists of an unsubstituted amino group; one or two C groups. １ ~C ４ amino group having an alkyl group; unsubstituted phenylamino group; or C １ ~C ４ C having an alkoxy group and 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 alkyl groups, carboxyl groups, hydroxyl groups, sulfol groups, and amino groups. More preferably, X １ and X ２ Each of these independently consists of an unsubstituted phenylamino group or (C １ ~C ４ (alkoxyphenyl)amino group. Preferably, the above (C １ ~C ４ The alkoxyphenyl is 4-methoxyphenyl. In one embodiment, the above C １ ~C ４ The alkyl group may further have substituents such as a phenyl group, and the phenyl group may further have substituents such as an amino group.

[0064] A more favorable Q １ Q ２ Q ３ , and R １ ~R ８ Examples include hydrogen atoms, chlorine atoms, and C １ ~C ４ alkyl group, C １ ~C ４ C having an alkoxy group and a sulfo group １ ~C ４Examples include alkoxy groups, nitro groups, carboxyl groups, and sulfo groups.

[0065] In formula (1) above, A represents a sulfo group or a carboxyl group, preferably a sulfo group, and m represents an integer from 1 to 3, preferably 2. In formula (2), n represents an integer from 0 to 3, preferably 1.

[0066] It is preferable that a polarizing film with higher contrast and higher polarization degree can be provided when the azo compound or salt thereof represented by formula (1) is the azo compound or salt thereof represented by formula (3) below, and the azo compound or salt thereof represented by formula (2) is the azo compound or salt thereof represented by formula (4). Compound A: (In formula (3), R １ ~R ４ Each of these independently represents an arbitrary substituent, and m represents an integer from 1 to 3. ) Compound B:

[0067] (In formula (4), R ５ ~R ８ Each of these independently represents an arbitrary substituent, R ９ (where represents a hydrogen or methoxy group, A represents a sulfo group or carboxyl group, and n represents an integer from 0 to 3.)

[0068] In formulas (3) and (4), the ring structures drawn with solid and dashed lines represent a phenyl (phenylene) group or a naphthyl (naphthylene) group.

[0069] In equations (3) and (4), R １ ~R ８ Each of these independently represents an arbitrary substituent, and as an arbitrary substituent, it has the same meaning as the substituents that may be present in formulas (1) and (2).

[0070] In formula (3), m represents an integer from 1 to 3, preferably 2. Also, in formula (4), R ９ represents a hydrogen or methoxy group, preferably hydrogen; A represents a sulfo group or a carboxyl group, preferably a sulfo group; and n represents an integer from 0 to 3, preferably 1.

[0071] In formula (3), R １ ~R ４ Each of them independently forms a hydrogen atom, C１ ~C ４ alkyl group, C １ ~C ４ C having an alkoxy group and a sulfo group １ ~C ４ It is an alkoxy group, and in formula (4), R ５ ~R ８ Each of them independently forms a hydrogen atom, C １ ~C ４ alkyl group, C １ ~C ４ C having an alkoxy group and a sulfo group １ ~C ４ When the group is an alkoxy group, it is preferable because it can provide a polarizing film with even higher transmittance and polarization.

[0072] The azo compound or its salt (compound A) represented by formulas (1) and (3) is often represented as formulas (1) and (3) in general, as described in Patent Document 10. However, it is generally believed that the amine species (Y) used during synthesis is coordinated, as shown in formula (5). In this application, the expected effect can be achieved regardless of which amine is coordinated. Examples of amine species (Y) include aqueous ammonia, amino alcohols, and hexamethylenetetramine, pyridine, etc. Preferably, monoethanolamine, N-methylethanolamine, diethanolamine, and pyridine, and more preferably monoethanolamine and N-methylethanolamine.

[0073] (In formula (5), X １ Q １ , R １ ~R ４ ,m represents the same meaning as in equation (1).

[0074] <Polarizing Film> In the present invention, by incorporating an azo compound represented by formula (1) or a salt thereof (compound A) and an azo compound represented by formula (2) or a salt thereof (compound B) into the substrate, a high-performance polarizing film exhibiting high polarization degree and high contrast, as well as high durability, can be obtained. Furthermore, when the single-component transmittance (Ys) after luminous efficiency correction in the 380 nm to 780 nm range is 39% or more, it is preferable that the orthogonal transmittance at a wavelength of 730 nm is 0% to 4%, more preferably 0% to 2%, and most preferably 0% to 1%.

[0075] <Substrate> The substrate contained in the polarizing film according to the present invention is preferably a film obtained by forming a film of a hydrophilic polymer that readily adsorbs the compounds (A) and (B) of the present invention, and dichroic dyes, particularly azo compounds. The hydrophilic polymer is not particularly limited, but examples include polyvinyl alcohol resins, amylose resins, starch resins, cellulose resins, and polyacrylate resins. Among such resins, polyvinyl alcohol resins or derivatives thereof are preferred from the viewpoint of dyeability, processability, and crosslinkability of dichroic dyes. The shape of the substrate is not particularly limited and can be made into any shape, such as a film, sheet, flat plate, curved plate, and hemispherical shape. The thickness of the substrate can be appropriately designed according to the application of the polarizing film, but is preferably in the range of 5 μm to 150 μm, and more preferably in the range of 10 μm to 100 μm. The polarizing film according to the present invention can be produced, for example, by forming the above-mentioned hydrophilic polymer as a substrate into a film, then incorporating compound A, compound B, an azo compound, or a salt thereof into the film, and then applying an orientation treatment such as stretching to the obtained film.

[0076] The azo compound represented by formula (1) or its salt (compound A) can be produced, for example, by the method described in Patent Document 1. Specific examples of compound A are listed below, but are not limited to these. The azo compound is expressed in the form of a free acid. In the following formula, the coordination of the amine species (Y) as represented by formula (5) is omitted, but any amine species may be coordinated.

[0077] The azo compound represented by formula (2) or its salt (compound B) can be produced by general azo compound synthesis methods, such as those described in Patent Documents 2-3. Specific examples of compound B are listed below, but are not limited to these. Note that the azo compound is expressed in the form of a free acid.

[0078] Compound A is typically a green dye with a maximum absorption wavelength exceeding 640 nm. Compound B is typically a purple to blue dye with a maximum absorption wavelength exceeding 570 nm. The polarizing film of the present invention preferably contains one type each of Compound A and Compound B. The polarizing film of the present invention preferably further contains one or more types of dichroic dyes other than Compound A and Compound B. The dichroic dyes preferably include a yellow to orange dichroic dye (hereinafter referred to as Compound C) and a red to purple dichroic dye (hereinafter referred to as Compound D) that have absorption in the short wavelength region. It is preferable that one type each of Compound C and Compound D are included. The polarizing film of the present invention has a higher degree of polarization and higher contrast over a wider wavelength range than conventional dye-based polarizing films. Furthermore, a polarizing plate made of this polarizing film exhibits higher durability against heat, humidity, and light compared to conventional dye-based polarizing plates.

[0079] Compound C, a yellow to orange dichroic dye with a maximum absorption wavelength of 400 nm or more and less than 500 nm, which can be used in the polarizing film of the present invention, can be a commercially available product such as 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, etc. In addition, stilbene-based orange dyes of formula (2) described in Example 1 of International Publication No. 2007 / 138980 and ureido-based orange dyes described in International Publication No. 2018 / 181470 and International Publication No. 2019 / 124161 can also be used as appropriate, but are not limited to these. Examples of the above compounds are shown below.

[0080] Compound D, a red to purple dichroic dye with a maximum absorption wavelength of 500 nm or more and less than 600 nm, which can be used in the polarizing film of the present invention, can be a commercially available product such as C.I. Direct Red 2, C.I. Direct Red 31, C.I. Direct Red 79, C.I. Direct Red 81, C.I. Direct Red 117, C.I. Direct Red 247, etc. Furthermore, ureido-based red dyes, such as those described in International Publication No. 2016 / 186194, International Publication No. 2016 / 186195, and International Publication No. 2016 / 186196, and 1-naphthol-3-sulfonic acid (J-acid)-based red dyes, such as those described in Japanese Patent Publication No. 08-291259, Japanese Patent Publication No. 2002-275381, and International Publication No. 2017 / 135391, may also be used as appropriate, but are not limited to these. Examples of the aforementioned compounds are shown below.

[0081] The azo compounds represented by formulas (1) to (5) above, and the dichroic dyes used in combination, may be in the form of free acids or salts, or they may be salts of metal ions or ammonium ions. Examples of metal ions include alkali metal ions such as lithium ions, sodium ions, and potassium ions, and alkaline earth metal ions such as calcium ions and magnesium ions. Examples of ammonium ions include ammonium ions in the narrow sense (NH₄). ４ ＋ Examples include methylammonium ion, dimethylammonium ion, triethylammonium ion, tetraethylammonium ion, tetra-n-propylammonium ion, tetra-n-butylammonium ion, monoethanolammonium ion, diethanolammonium ion, triethanolammonium ion, N-methyl-N-monoethanolammonium ion, etc. More specifically, for example, in the case of free acids, sulfonic acid (-SO ３ H) is used, and in the case of sodium ions, sodium sulfonate (-SO ３ In the case of ammonium ions, use Na, and ammonium sulfonate (-SO ３ NH ４ ) In the case of N-methyl-N-monoethanolammonium ion, -SO ３ － ・[MeNH ２ CH ２ CH ２ OH] ＋ It represents.

[0082] In the polarizing film according to the present invention, it is preferable that the blending ratio of the azo compounds used be adjusted so that the transmittance is within a preferred range as described later. The polarization performance of the polarizing film is affected not only by the blending ratio of each azo compound in the polarizing film, but also by various factors such as the degree of swelling and stretching ratio of the substrate on which the azo compounds are adsorbed, the dyeing time, the dyeing temperature, the pH during dyeing, and the effect of salt. Therefore, such blending ratios can be adjusted as appropriate based on the explanation described later.

[0083] (Transmittance after luminous sensitivity correction) The transmittance of the polarizing film, etc., according to the present invention is measured in accordance with JIS Z 8722:2009.

[0084] (Combined transmittance after luminous sensitivity correction) The polarizing film, etc., according to the present invention preferably has a combined transmittance of 35% to 70% after luminous sensitivity correction in the wavelength range of 380 nm to 780 nm. The combined transmittance after luminous sensitivity correction is the transmittance corrected to luminous sensitivity for one measurement sample (e.g., polarizing film or polarizing plate) according to JIS Z 8722:2009. As performance of the polarizing film or polarizing plate, a higher combined transmittance after luminous sensitivity correction is required, but if the combined transmittance after luminous sensitivity correction is 35% to 70%, brightness can be expressed without discomfort even when used in various display devices. If the combined transmittance after luminous sensitivity correction exceeds 70%, the degree of polarization may decrease significantly, which is undesirable. On the other hand, the degree of polarization tends to decrease as the transmittance increases, so from the viewpoint of balancing with the degree of polarization, the combined transmittance after luminous sensitivity correction is more preferably 35% to 60%, even more preferably 37% to 55%, and particularly preferably 39% to 50%.

[0085] The polarization degree of the polarizing film is preferably 50% to 100%, more preferably 80% to 100%, even more preferably 95% to 100%, and particularly preferably 99% to 100%. While a higher polarization degree is preferable, the relationship between polarization degree and transmittance can be adjusted to suit the transmittance and polarization degree, depending on whether brightness or polarization degree (or contrast) is prioritized, allowing for application in display devices and the like.

[0086] Regarding the absorption band, adjusting the transmittance in the 400-700 nm range causes light leakage on the longer wavelength side, resulting in a decrease in actual contrast (reduced display quality). To suppress this, it is preferable to have a uniform absorption band in the range of 380-780 nm. For example, in order to be effective against light leakage on the longer wavelength side above 700 nm, it is preferable to adjust the orthogonal transmittance above 700 nm, specifically the orthogonal transmittance at 730 nm. The transmittance is preferably 0-20%, more preferably 0-4%, and more preferably adjusted to 0-1%.

[0087] Next, we will explain a specific method for producing a polarizing film, using the example of a case where an azo compound is adsorbed onto a polyvinyl alcohol-based resin substrate. Note that the method for producing a polarizing film according to the present invention is not limited to the following method.

[0088] (Preparation of base film) The film that will be the basis of the base film (hereinafter referred to as base film or film) can be made by forming a film of polyvinyl alcohol resin. The polyvinyl alcohol resin is not particularly limited, and commercially available resins may be used, or resins synthesized by known methods may be used. The polyvinyl alcohol resin can be obtained, for example, by saponifying a polyvinyl acetate resin. Examples of polyvinyl acetate resins include polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids. The degree of saponification of the polyvinyl alcohol resin is usually preferably about 85 to 100 mol%, and more preferably 95 mol% or more. The polyvinyl alcohol resin may be further modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can also be used. Furthermore, the degree of polymerization of the polyvinyl alcohol-based resin refers to the viscosity-average degree of polymerization, which can be determined by methods well known in the art, and is usually preferably around 1,000 to 10,000, and more preferably around 1,500 to 6,000.

[0089] The method for forming the polyvinyl alcohol-based resin film is not particularly limited, and the film can be formed using known methods. In this case, the polyvinyl alcohol-based resin film may contain plasticizers such as glycerin, ethylene glycol, propylene glycol, and low molecular weight polyethylene glycol. The plasticizer content is preferably 5 to 20% by mass, and more preferably 8 to 15% by mass, relative to the total film. The film thickness of the raw film is not particularly limited, but for example, it is about 5 μm to 150 μm, preferably about 10 μm to 100 μm.

[0090] (Swelling Process) The obtained raw film is subjected to a swelling treatment. The swelling treatment is preferably carried out by immersing the raw film in a solution at 20 to 50°C for 30 seconds to 10 minutes, and the solution is preferably water. The stretching ratio of the raw film due to swelling is preferably adjusted to 1.00 to 1.50 times, and more preferably to 1.10 to 1.35 times. If the time for manufacturing the polarizing film is to be shortened, the swelling treatment can be omitted because the raw film also swells during the dyeing treatment described later.

[0091] (Dyeing Process) Next, a dyeing process is carried out in which a dichroic dye such as an azo compound is adsorbed and impregnated onto the film obtained by the swelling process. If the swelling process is omitted, the swelling process of the raw film can be carried out simultaneously in the dyeing process. In the dyeing process, for example, an azo compound, which is a dichroic dye exemplified in Masahiro Irie (ed.), "Applications of Functional Dyes," 1st edition, CMC Corporation, June 2002, pp. 98-100, may be used to adjust the color of the resin film to an extent that does not impair the performance of the polarizing film according to the present invention.

[0092] The dyeing process is not particularly limited as long as it involves adsorbing and impregnating the film with an azo compound as a dichroic dye. For example, it is preferable to color the film by immersing it in a dyeing solution, or it is also possible to color the film by coating it with the dyeing solution. The concentration of each azo compound in the dyeing solution is not particularly limited as long as the film is sufficiently colored, but it can be adjusted, for example, within the range of 0.05 g / liter to 100 g / liter.

[0093] The temperature of the dyeing solution in the dyeing process is preferably 5 to 60°C, more preferably 20 to 50°C, and particularly preferably 35 to 50°C. The immersion time of the film in the dyeing solution can be adjusted as appropriate, preferably between 30 seconds and 20 minutes, and more preferably between 1 and 10 minutes.

[0094] The dyeing solution may, in addition to the azo compound used in the present invention, further contain a dyeing aid as needed. Examples of dyeing aids include sodium carbonate, sodium bicarbonate, sodium chloride, sodium sulfate, anhydrous sodium sulfate, and sodium tripolyphosphate. The content of the dyeing aid can be arbitrarily adjusted depending on the immersion time and temperature of the dyeing solution based on the dyeing properties of the dye used, but it is preferably 0.01 to 5% by mass in the dyeing solution, and more preferably 0.1 to 2% by mass.

[0095] (Washing Step 1) After the dyeing step, a washing step (hereinafter also referred to as "washing step 1") can be performed to remove the dyeing solution adhering to the surface of the resin film. By performing washing step 1, it is possible to suppress the migration of dye remaining on the surface of the resin film into the liquid to be processed next. In washing step 1, water is generally used as the washing solution. The washing method is preferably to immerse the dyed resin film in the washing solution, or to wash by applying the washing solution to the resin film. The washing time is not particularly limited, but is preferably 1 to 300 seconds, and more preferably 1 to 60 seconds. The temperature of the washing solution in washing step 1 must be such that the material constituting the resin film (for example, a hydrophilic polymer, in this case a polyvinyl alcohol-based resin) does not dissolve, and the washing treatment is generally performed at 5 to 40°C. However, washing step 1 can be omitted as it does not affect the performance of the polarizing film.

[0096] (Step of incorporating a crosslinking agent and / or water-resistant agent into the film) After the dyeing step or washing step 1, a crosslinking agent and / or water-resistant agent may be incorporated. The method of incorporating a crosslinking agent and / or water-resistant agent into the resin film is preferably by immersing the resin film in a treatment solution containing the crosslinking agent and / or water-resistant agent, or the treatment solution may be applied or coated onto the resin film. The treatment solution contains at least one type of crosslinking agent and / or water-resistant agent and a solvent. The temperature of the treatment solution is preferably 5 to 70°C, and more preferably 5 to 50°C. The treatment time in this step is preferably 30 seconds to 6 minutes, and more preferably 1 to 5 minutes.

[0097] Examples of crosslinking agents include boric acid, boron compounds such as borax or ammonium borate, polyhydric aldehydes such as glyoxal or glutaraldehyde, polyhydric isocyanate compounds such as biuret type, isocyanurate type or block type, and titanium compounds such as titanium oxysulfate. Other options include ethylene glycol glycidyl ether and polyamide epichlorohydrin. Examples of water-resistant agents include succinic acid peroxide, ammonium persulfate, calcium perchlorate, benzoin ethyl ether, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, ammonium chloride, or magnesium chloride, but boric acid is preferred. The solvent for the crosslinking agent and / or water-resistant agent is not particularly limited, but water is preferred. The concentration of the crosslinking agent and / or water-resistant agent in the treatment solution can be appropriately determined depending on the type of agent. For example, when using boric acid, the concentration of boric acid in the treatment solution is preferably 0.1 to 6.0% by mass, and more preferably 1.0 to 4.0% by mass. Furthermore, if it is desired to shorten the time required to manufacture the polarizing film, or if crosslinking or water-resistant treatment is unnecessary, the process can be omitted.

[0098] (Stretching Process) After the dyeing process, or optionally after the washing process 1 or the process of adding a crosslinking agent and / or a water-resistant agent, the stretching process is carried out. The stretching process is performed by stretching the resin film uniaxially. The stretching method may be either a dry stretching method or a wet stretching method. The stretching ratio is preferably 3 times or more, and more preferably 5 to 8 times.

[0099] In the dry stretching method, when the stretching heating medium is air, it is preferable to stretch the resin film at a temperature of room temperature to 180°C. Furthermore, the humidity is preferably in an atmosphere of 20-95% RH. Examples of methods for heating the resin film include, but are not limited to, the inter-roll zone stretching method, the roll heating stretching method, the hot pressure stretching method, and the infrared heating stretching method. The dry stretching process may be carried out in a single stage or in two or more stages.

[0100] In the wet stretching method, it is preferable to stretch the resin film in water, a water-soluble organic solvent, or a mixed solution thereof. More preferably, the stretching process is carried out while immersing the resin film in a solution containing at least one crosslinking agent and / or water-resistant agent. The crosslinking agent and / or water-resistant agent can be the same as those described above in the step of incorporating the crosslinking agent and / or water-resistant agent. The concentration of the crosslinking agent and / or water-resistant agent in the solution during the stretching process is preferably 0.5 to 15% by mass, and more preferably 2.0 to 8.0% by mass. The stretching temperature is preferably 40 to 60°C, and more preferably 45 to 58°C. The stretching time is usually 30 seconds to 20 minutes, and preferably 2 to 5 minutes. The wet stretching process may be carried out in one stage or in two or more stages.

[0101] (Cleaning Step 2) After the stretching step, crosslinking agents and / or water-resistant agents may precipitate on the surface of the resin film, or foreign matter may adhere to it. Therefore, a cleaning step (hereinafter also referred to as "Cleaning Step 2") to clean the surface of the resin film may be optionally performed. The cleaning time is preferably 1 second to 5 minutes. The cleaning method is preferably immersing the resin film in a cleaning solution, but the cleaning solution can also be applied to or coated onto the resin film. Water is preferred as the cleaning solution. The cleaning process may be carried out in one step or in a multi-stage process of two or more steps. The temperature of the cleaning solution in the cleaning step is not particularly limited, but is usually 5 to 50°C, preferably 10 to 40°C. If it is desired to shorten the time required to manufacture the polarizing film, this step may be omitted, but it is preferable to perform it from a quality perspective.

[0102] In addition to water, other examples of processing liquids or solvents used in each of the processing steps described above include alcohols such as dimethyl sulfoxide, N-methylpyrrolidone, methanol, ethanol, propanol, isopropyl alcohol, glycerin, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, or trimethylolpropane, and amines such as ethylenediamine and diethylenetriamine. The processing liquid or solvent is not limited to these, but water is most preferred. Furthermore, these processing liquids or solvents may be used individually or as a mixture of two or more.

[0103] (Drying Process) After the stretching process or washing process 2, the resin film is dried. Although the drying process can be carried out by natural drying, in order to improve drying efficiency, it is possible to perform the drying by compression with a roll, removal of surface moisture with an air knife or water-absorbing roll, etc., and it is also possible to perform forced-air drying. The drying temperature is preferably 20 to 100°C, and more preferably 60 to 100°C. The drying time is preferably 30 seconds to 20 minutes, and more preferably 5 to 10 minutes.

[0104] (Polarizing plate) The polarizing plate according to the present invention comprises a polarizing film containing the above-mentioned azo compound in a base film, and a transparent protective layer provided on one or both sides of the polarizing film. The transparent protective layer is used to improve the water resistance and handling properties of the polarizing film.

[0105] The transparent protective layer is a protective film formed using a transparent material. The protective film is a film having a layered shape that can maintain the shape of the polarizing film, and is preferably made of a transparent resin that has excellent transparency, mechanical strength, thermal stability, moisture shielding properties, etc. On the other hand, a protective film made of other materials that can have functions equivalent to such a transparent resin may also be used.

[0106] When a polarizing plate is bonded to a display device such as a liquid crystal display or OLED, various functional layers for improving display quality such as viewing angle, or layers or films that enhance brightness, can be provided on the surface of the transparent protective layer that is not exposed. Examples of these functional layers include layers or films that control phase differences. It is preferable that the polarizing plate is bonded to these films with an adhesive. Furthermore, these functional layers or films can also be used as substitutes for the transparent protective layer that constitutes the polarizing plate.

[0107] Furthermore, the polarizing plate may appropriately have various known functional layers such as an anti-reflective layer, an anti-glare layer, or a hard coat layer on the exposed surface of the protective layer or protective film. When producing such functional layers, it is preferable to coat the material having the various functional properties onto the exposed surface of the protective layer or protective film. Alternatively, it is also possible to bond such functional layers or films to the exposed surface of the protective layer or protective film via an adhesive or bonding agent.

[0108] Examples of plastics that make up the protective film include thermoplastic resins such as polyester resins, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, or acrylic resins; thermosetting resins such as acrylic, urethane, acrylic urethane, epoxy, or silicone resins; and UV-curable resins. Among these, as polyolefin resins, amorphous polyolefin resins having polymerization units of cyclic polyolefins such as norbornene monomers or polycyclic norbornene monomers are used. Generally, it is preferable to select a protective film that does not impair the performance of the polarizing film, and triacetylcellulose (TAC) or norbornene made from cellulose acetate resins are particularly preferred as such protective films. Furthermore, the protective film may be treated with a hard coat, an anti-reflective coating, or a treatment for preventing sticking, diffusion, anti-glare, etc., as long as it does not impair the effects of the present invention. The thickness of the transparent protective layer can be appropriately designed depending on the application of the polarizing film, but is preferably in the range of 1 μm to 200 μm, more preferably in the range of 5 μm to 150 μm, and particularly preferably in the range of 10 μm to 100 μm.

[0109] Specific examples of phase difference films include various known technologies such as films made by stretching transparent resins such as polycarbonate resin, and phase difference films made by coating, oriented, and fixing various liquid crystalline compounds. Phase difference films are used as laminated films bonded to polarizing plates via adhesives or tacks. The phase difference film is arbitrary, and various known types can be used depending on the display device used. The thickness of the film and its optical properties (in-plane retardation value Re and thickness-direction retardation value Rth of the phase difference film) are not particularly limited, and the phase difference film may consist of multiple layers.

[0110] For example, in liquid crystal display devices, phase difference films are known to be used as optical compensation films to expand the viewing angle and improve image coloring. Depending on the active matrix system, passive matrix system, and various liquid crystal driving modes (TN mode, VA mode, IPS mode, etc.), the optical properties of the film are controlled to achieve the desired optical anisotropy. In addition, depending on the required optical compensation function, multiple phase difference films may be used in combination.

[0111] Furthermore, in OLEDs, a circular polarizer (a combination of a polarizer and a phase difference film) is sometimes placed on the viewing surface of the image display panel to suppress internal reflection phenomena. The phase difference film in this case may be, for example, a λ / 4 film alone, or a configuration in which a λ / 2 film and a λ / 4 film are laminated, but is not limited to these. Known technologies also use circular polarizers that combine a single or multiple phase difference films, and the polarizer of the present invention can also be used in combination with these technologies.

[0112] The polarizing plate preferably further comprises an adhesive layer between the transparent protective layer and the polarizing film for bonding the transparent protective layer to the polarizing film. The adhesive constituting the adhesive layer is not particularly limited, but a polyvinyl alcohol-based adhesive is preferred. Examples of polyvinyl alcohol-based adhesives include, but are not limited to, Exceval RS-2117 (manufactured by Kuraray Co., Ltd.). A crosslinking agent and / or a water-resistant agent may also be added to the adhesive. As the polymer constituting the polyvinyl alcohol-based adhesive, a maleic anhydride-isobutylene copolymer is preferred, and an adhesive mixed with a crosslinking agent may be used if necessary. Examples of maleic anhydride-isobutylene copolymers include Isoban #18 (manufactured by Kuraray Co., Ltd.), Isoban #04 (manufactured by Kuraray Co., Ltd.), ammonia-modified Isoban #104 (manufactured by Kuraray Co., Ltd.), ammonia-modified Isoban #110 (manufactured by Kuraray Co., Ltd.), imidized Isoban #304 (manufactured by Kuraray Co., Ltd.), and imidized Isoban #310 (manufactured by Kuraray Co., Ltd.). Water-soluble polyvalent epoxy compounds can be used as crosslinking agents. Examples of water-soluble polyvalent epoxy compounds include Denacol EX-521 (manufactured by Nagase Chemtec Co., Ltd.) and Tetrat-C (manufactured by Mitsui Gas Chemical Co., Ltd.). In addition, known adhesives other than polyvinyl alcohol-based resins, such as urethane-based, acrylic-based, and epoxy-based adhesives, can also be used. In particular, it is preferable to use acetoacetyl-modified polyvinyl alcohol, and it is even preferable to use a polyvalent aldehyde as its crosslinking agent. Furthermore, from the viewpoint of improving the adhesive strength or water resistance of the adhesive, additives such as zinc compounds, chlorides, or iodides can be included in the adhesive alone or in combination at a concentration of about 0.1 to 10% by mass. The additives that can be included in the adhesive are not particularly limited and can be selected as appropriate. After bonding the transparent protective layer and the polarizing film with the adhesive, a polarizing plate can be manufactured by drying or heat-treating it at an appropriate temperature.

[0113] When a polarizing plate is bonded to a display device such as a liquid crystal display or OLED, various functional layers for improving viewing angle and / or contrast, or layers or films for improving brightness, can be provided on the surface of the transparent protective layer or film that will be the non-exposed surface afterward. These functional layers include, for example, layers or films that control phase differences. It is preferable that the polarizing plate is bonded to these films or display devices using an adhesive.

[0114] To bond the polarizing plate to optical components, supports, or display devices, an adhesive layer may be formed on one or both sides of the polarizing plate. The adhesive layer can be made of adhesives or tacks, but acrylic resin, polyester resin, polyurethane resin, and other tacks are preferred. The tacks used are not limited to these and can be appropriately selected depending on the application and components.

[0115] The polarizing film or polarizing plate according to the present invention may be provided with a protective layer and / or a functional layer, as well as a transparent support such as glass, quartz, or sapphire, as needed, and is applicable to, but not limited to, liquid crystal projectors, OLEDs, calculators, watches, laptop computers, word processors, liquid crystal televisions, polarizing lenses, polarizing glasses, car navigation systems, or indoor and outdoor measuring instruments and displays. In particular, the polarizing film or polarizing plate according to the present invention is suitably used in liquid crystal display devices, such as reflective liquid crystal display devices, semi-transparent liquid crystal display devices, or OLEDs. It is also suitably used in various displays that require high polarization performance and durability, such as in-vehicle displays or outdoor displays (for example, for industrial instrument displays and wearable applications). A display device using the polarizing film or polarizing plate according to the present invention can express high-quality paper-like white and neutral black. Furthermore, a display device using the polarizing film or polarizing plate according to the present invention is a display device that has high durability, high reliability, high contrast over the long term, and high color reproducibility.

[0116] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0117] [Example 1] <Synthesis Example 1-1> (Step 1) A tetrakisazo compound represented by formula (6) was obtained according to the method described in International Publication No. 2012 / 108169. The process is described in detail below. 25.3 parts by weight of 4-aminobenzene-1,3-disulfonic acid was added to 500 parts by weight of water, cooled to below 10°C, 31.3 parts by weight of 35% hydrochloric acid aqueous solution was added, then 6.9 parts by weight of sodium nitrite was added, and the mixture was stirred at 5-10°C for 1 hour to diazotize it. Then, 10.7 parts by weight of 3-methylaniline dissolved in dilute hydrochloric acid aqueous solution was added as a primary coupler (coupling component), and sodium carbonate was added while stirring at 10-30°C to adjust the pH to 3, and the mixture was stirred further to complete the coupling reaction, filtered, and 29.7 parts by weight of a monoazoamino compound represented by formula (1A) was obtained.

[0118] Next, 29.7 parts by weight of the monoazoamino compound of formula (1A) obtained was added to 400 parts by weight of water and dissolved with sodium hydroxide. 25.0 parts by weight of a 35% hydrochloric acid aqueous solution was added at 10-30°C, followed by 5.5 parts by weight of sodium nitrite, and the mixture was stirred at 20-30°C for 1 hour to diazotize it. Then, 8.6 parts by weight of 3-methylaniline dissolved in dilute hydrochloric acid aqueous solution was added as a secondary coupler, and sodium carbonate was added while stirring at 20-30°C to adjust the pH to 3. The mixture was further stirred to induce a coupling reaction, filtered, and 31.3 parts by weight of the disazoamino compound represented by formula (2A) was obtained.

[0119] Next, 31.3 parts by weight of the disazoamino compound of formula (2A) obtained was added to 250 parts by weight of water and dissolved with sodium hydroxide. Then, 20.0 parts by weight of a 35% hydrochloric acid aqueous solution was added at 20-30°C, followed by 4.4 parts by weight of sodium nitrite, and the mixture was stirred at 20-30°C for 1 hour to diazotize it. To this, 9.8 parts by weight of 2,5-dimethoxyaniline dissolved in dilute hydrochloric acid aqueous solution was added as a tertiary coupler, and sodium carbonate was added while stirring at 20-30°C to adjust the pH to 3.5. The mixture was further stirred to complete the coupling reaction, filtered, and 32.6 parts by weight of the trisazoamino compound represented by formula (3A) was obtained.

[0120] Next, 32.6 parts by weight of the trisazoamino compound of formula (3A) obtained was added to 200 parts by weight of water and dissolved with sodium hydroxide. Then, 16.0 parts by weight of a 35% hydrochloric acid aqueous solution was added at 20-30°C, followed by 3.5 parts by weight of sodium nitrite, and the mixture was stirred at 20-30°C for 1 hour to diazotize it and obtain the diazotized product of the trisazoamino compound. Furthermore, 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 dissolved in sodium carbonate to make it weakly alkaline to obtain a solution of the quaternary coupler.

[0121] To this quaternary coupler solution, while maintaining the pH at 8-10, the diazotized trisazoamino compound obtained earlier was injected, stirred to complete the coupling reaction, filtered, and 38.2 parts of the tetrakisazo compound shown in formula (6) were obtained.

[0122] (Step 2) 38.2 parts of the tetrakisazo compound obtained in Step 1 were added to 900 parts of water and stirred to suspend. 28.4 parts of N-methylethanolamine and 11.3 parts of copper sulfate pentahydrate were added and the mixture was stirred at 90-98°C for 10 hours to complete the copperization reaction. After that, the copperized azo compound was salted out with sodium chloride, filtered, and dried to obtain 7.0 parts of the copperized azo compound represented by [Compound Example A-1].

[0123] <Synthesis Example 1-2> (Process) A trisazo compound represented by [Compound Example B-17] described in Example 1 of Japanese Patent No. 2622748 was obtained according to the method described in Japanese Patent No. 2622748.

[0124] <Preparation of polarizing films and polarizing plates> A polyvinyl alcohol resin film (VF-PE#4500 manufactured by Kuraray Co., Ltd.; hereinafter simply referred to as "film") with a saponification degree of 99 mol% or more and a film thickness of 45 μm was immersed in 35°C warm water for 3 minutes to swell. The swollen film was then immersed for 5 minutes in a 48°C aqueous solution consisting of 1.0 part by weight of an azo compound represented by [Compound Example A-1] as compound A, 0.3 parts by weight of an azo compound represented by [Compound Example B-17] as compound B, 0.1 parts by weight of an azo compound represented by [Compound Example C-1] as compound C, 0.3 parts by weight of C.I. Direct Red 117 as compound D, 1.5 parts by weight of sodium tripolyphosphate, 3.0 parts by weight of anhydrous sodium sulfate, and 1500 parts by weight of water to incorporate the azo compounds. A film containing an azo compound was washed with water, and after washing, it was crosslinked with boric acid in an aqueous solution containing 2.7% by weight of boric acid at 40°C for 5 minutes. The film obtained after the crosslinking treatment was stretched to 6.0 times its original size while being crosslinked in an aqueous solution containing 3.0% by weight of boric acid at 58°C for 5 minutes. While maintaining the tension of the stretched film, it was washed with room temperature water for 10 seconds. The film obtained after the washing treatment was immediately dried at 70°C for 3 minutes to obtain a polarizing film. By the above method, a polarizing film according to the present invention containing an azo compound having the structure of formula (1) and an azo compound having the structure of formula (2) was prepared. A polarizing plate according to the present invention was fabricated by laminating a 60 μm thick alkali-treated triacetylcellulose film (TG-60UL, manufactured by Fujifilm Corporation, hereinafter abbreviated as "TAC") as a transparent protective layer on both sides of the polarizing film using a polyvinyl alcohol adhesive, and then laminating it, resulting in a structure of TAC / adhesive layer / polarizing film / adhesive layer / TAC. The obtained polarizing plate maintained the optical performance of the above polarizing film, particularly its single-layer transmittance, hue, and polarization degree. This polarizing plate was used as the measurement sample for Example 1.

[0125] [Example 2]

[0126] <Preparation of polarizing film and polarizing plate> A polarizing plate was prepared in the same manner as the preparation of the polarizing film and polarizing plate in Example 1, except that compound C used in the preparation of the polarizing film in Example 1 was replaced with 0.2 parts by weight of the azo compound represented by [Compound Example C-2].

[0127] [Example 3] <Preparation of polarizing film and polarizing plate> A polarizing plate was prepared in the same manner as the preparation of the polarizing film and polarizing plate in Example 1, except that compound D used in the preparation of the polarizing film in Example 1 was replaced with 0.5 parts by weight of the azo compound represented by [Compound Example D-1].

[0128] [Example 4] <Preparation of polarizing film and polarizing plate> A polarizing plate was prepared in the same manner as the preparation of the polarizing film and polarizing plate in Example 1, except that the four types of compounds used in the preparation of the polarizing film in Example 1 were replaced with three types of compounds: "1.4 parts by weight of the azo compound represented by [Compound Example A-1] as Compound A, 0.3 parts by weight of the azo compound represented by [Compound Example B-17] as Compound B, and 1.8 parts by weight of the azo compound represented by [Compound Example D-1] as Compound D".

[0129] [Example 5] <Synthesis Example 5> (Step) A trisazo compound represented by formula (7) was obtained with reference to the method described in Japanese Patent Publication No. 2622748. <Preparation of polarizing film and polarizing plate> A polarizing plate was prepared in the same manner as the preparation of the polarizing film and polarizing plate in Example 3, except that compound B used in the preparation of the polarizing film in Example 3 was replaced with 0.6 parts by weight of the azo compound represented by formula (7).

[0130] [Example 6] <Synthesis Example 6> (Step) A trisazo compound represented by formula (8) was obtained with reference to the method described in Japanese Patent Publication No. 2622748. <Preparation of polarizing film and polarizing plate> A polarizing plate was prepared in the same manner as the preparation of the polarizing film and polarizing plate in Example 3, except that compound B used in the preparation of the polarizing film in Example 3 was replaced with 0.5 parts by weight of the azo compound represented by formula (8).

[0131] [Comparative Example 1] A polarizing plate was prepared in the same manner as in Example 1, except that the four compounds used in the preparation of the polarizing film in Example 1 were changed to "compounds represented by compound example 99 (formula (9) below) and compound example 1 (formula (10) below) described in Example 8 of Patent Document 1, C.I. Direct Orange 39, and C.I. Direct Red 117." This polarizing plate is composed of compounds represented by formulas (9) and (10) below as dyes corresponding to compounds A and B, C.I. Direct Orange 39 as compound C, and C.I. Direct Red 117 as compound D. However, the maximum absorption wavelength of the dichroic dye of formula (9) was 579 nm, and it exhibited a purple color.

[0132] [Comparative Example 2] A polarizing plate was prepared in the same manner as in Example 1, except that the four types of compounds used in the preparation of the polarizing film in Example 1 were replaced with the compounds represented by Compound Example 7-39 (formula (11) below) and Compound Example 5-1 (formula (12) below) described in Example 87 of Patent Document 2, and the compounds described in Compound Example C-1 and Compound Example D-1. This polarizing plate is composed of the compounds represented by the following formulas (11) and (12) as dyes corresponding to Compound A and Compound B, Compound Example C-1 as Compound C, and Compound Example D-1 as Compound D. However, the maximum absorption wavelengths of the dichroic dyes of formula (11) and formula (12) were 603 nm and 609 nm, respectively, and both exhibited a blue color.

[0133] [Comparative Example 3] A polarizing plate was prepared in the same manner as in Example 1, except that the four types of compounds used in the preparation of the polarizing film in Example 1 were changed to "compounds represented by compound example 111 (formula (9) below) and compound example 138 (formula (13) below) described in Example 19 of Patent Document 3, compound example C-1 and compound example D-2". This polarizing plate is composed of compounds represented by formulas (9) and (13) below as dyes corresponding to compounds A and B, compound example C-1 as compound C, and compound example D-2 as compound D.

[0134] [Comparative Example 4] A polarizing plate was prepared in the same manner as in Example 1, except that the four types of compounds used in the preparation of the polarizing film in Example 1 were changed to "compounds represented by compound example 120 (formula (11) below) and compound example 138 (formula (13) below) described in Example 13 of Patent Document 3, compound example C-1, and C.I. Direct Red 117." This polarizing plate is composed of compounds represented by formulas (11) and (13) below as dyes corresponding to compounds A and B, compound example C-1 as compound C, and compound example D-1 as compound D.

[0135] [Comparative Example 5] A polarizing plate was prepared in the same manner as in Example 1, except that the four types of compounds used in the preparation of the polarizing film in Example 1 were changed to "compounds represented by compound example 5-8 (formula (6) below) and compound example 4-1 (formula (14) below) described in Example B1 of Patent Document 4, C.I. Direct Orange 39, and [compound example D-3]". This polarizing plate is composed of compounds represented by formulas (6) and (14) below as dyes corresponding to compounds A and B, C.I. Direct Orange 39 as compound C, and [compound example D-3] as compound D.

[0136] [Comparative Example 6] A polarizing plate was prepared in the same manner as in Example 1, except that the four types of compounds used in the preparation of the polarizing film in Example 1 were changed to three types of compounds represented by "Compound Example 2-8 (Formula (6)) described in Example 18 of Patent Document 2, [Compound Example C-1] and [Compound Example D-1]". This polarizing plate is composed of 1.3 parts by weight of the compound represented by Formula (6) below as dyes corresponding to Compound A and Compound B, 0.1 parts by weight of [Compound Example C-1] as Compound C, and 0.3 parts by weight of [Compound Example D-1] as Compound D.

[0137] [Comparative Example 7] A polarizing plate was prepared in the same manner as in Example 1, except that the four types of compounds used in the preparation of the polarizing film in Example 1 were changed to three types: "the compound represented by compound example 17 (formula (15)) described in Patent Document 1, Example 4, [compound example C-1], and C.I. Direct Red 117." This polarizing plate is composed of the compound represented by formula (15) below as the dye corresponding to compound A and compound B, [compound example C-1] as compound C, and C.I. Direct Red 117 as compound D.

[0138] [Comparative Example 8] A polarizing plate was prepared in the same manner as in Example 1, except that the four types of compounds used in the preparation of the polarizing film in Example 1 were changed to three types of compounds: "compound example 2-4 (formula (16)) described in Example 6 of Patent Document 5, [compound example C-1] and [compound example D-4]". This polarizing plate is composed of the compound represented by formula (16) below as the dye corresponding to compound A and compound B, compound C as [compound example C-1], and compound D as [compound example D-4].

[0139] [Comparative Example 9] A polarizing plate was prepared in the same manner as in Example 1, except that the four types of compounds used in the preparation of the polarizing film in Example 1 were changed to three types: "the compound represented by compound example 2-20 (formula (17) below) described in Example 3 of Patent Document 9, C.I. Direct Orange 39, and [compound example D-5]". This polarizing plate is composed of the compound represented by formula (17 below) as the dye corresponding to compound A and compound B, C.I. Direct Orange 39 as compound C, and [compound example D-5] as compound D.

[0140] [Comparative Example 10] A polarizing plate was prepared in the same manner as in Example 1, except that the four types of compounds used in the preparation of the polarizing film in Example 1 were changed to three types: "compound example 41 (formula (18) below) and compound example 1 (formula (10) below) described in Example 5 of Patent Document 1, and [compound example C-1]". This polarizing plate is composed of compounds represented by formulas (18) and (10) below as dyes corresponding to compounds A and B, and compound example C-1 as compound C.

[0141] [Comparative Example 11] A polarizing plate was prepared in the same manner as in Example 1, except that the four types of compounds used in the preparation of the polarizing film in Example 1 were changed to three types: "the compound represented by compound example 2-10 (formula (19) below) described in Example 22 of Patent Document 10, [compound example C-2] and [compound example D-6]". This polarizing plate is composed of 0.62 parts by weight of the compound represented by formula (19 below) as dyes corresponding to compound A and compound B, 0.69 parts by weight of [compound example C-2] as compound C, and 0.28 parts by weight of [compound example D-6] as compound D.

[0142] [Comparative Example 12] A polarizing plate was prepared in the same manner as in Example 1, except that the four types of compounds used in the preparation of the polarizing film in Example 1 were changed to three types: "the compound represented by compound example 3-20 (formula (20) below) described in Example 3 of Patent Document 11, C.I. Direct Orange 39, and [compound example D-7]". This polarizing plate is composed of the compound represented by formula (20) below as the dye corresponding to compound A and compound B, C.I. Direct Orange 39 as compound C, and [compound example D-7] as compound D.

[0143] [Comparative Example 13] A polarizing plate was prepared in the same manner as in Comparative Example 6, except that the parts by weight of the dye used were changed. Specifically, compound B was changed to 2.0 parts by weight of the azo compound represented by formula (6), compound C to 0.1 parts by weight of the azo compound represented by [Compound Example C-1], and compound D to 0.3 parts by weight of the azo compound represented by [Compound Example D-1]. By changing the parts by weight, a polarizing plate with a single-component transmittance (Ys) after luminous efficiency correction of 40.0% was obtained.

[0144] [Comparative Example 14] A polarizing plate was prepared using the same method as in Comparative Example 11, except that the parts by weight of the dye used were changed. Specifically, compound B was changed to 1.5 parts by weight of the azo compound represented by formula (19) above, compound C was changed to 1.5 parts by weight of the azo compound represented by [Compound Example C-2], and compound D was changed to 0.9 parts by weight of the azo compound represented by [Compound Example D-6]. By changing the parts by weight, a polarizing plate with a single-component transmittance of 40.0% after luminous efficiency correction was obtained.

[0145] <Evaluation> The measurement samples obtained in Examples 1 to 6 and Comparative Examples 1 to 14 were evaluated as follows.

[0146] <Parallel Polarization Transmittance Ky, Orthogonal Polarization Transmittance Kz> The parallel polarization transmittance (Ky) and orthogonal polarization transmittance (Kz) of each sample were measured using a spectrophotometer (Hitachi High-Tech Science Co., Ltd. UH-4150). Here, Ky is the transmittance when the absorption axis of the absolute polarizer and the absorption axis of the polarizing film and polarizing plate are superimposed in parallel, and Kz is the transmittance when the absorption axis of the absolute polarizer and the absorption axis of the polarizing plate and polarizing film are superimposed orthogonally. The parallel polarization transmittances Ky and Kz for each wavelength were measured at wavelength intervals of 1 to 10 nm in the range of 380 to 780 nm.

[0147] <Single-piece transmittance Ts, parallel-position transmittance Tp, and orthogonal-position transmittance Tc> Single-piece transmittance Ts is the spectral transmittance at each wavelength when the measurement sample is measured with a single sample. Parallel-position transmittance Tp is the spectral transmittance at each wavelength when two measurement samples are superimposed so that their absorption axes are parallel. Orthogonal-position transmittance Tc is the spectral transmittance when two polarizers are superimposed so that their absorption axes are orthogonal. Using the Ky and Kz values ​​obtained from the measurements in the 380-780 nm range, various transmittances in the 380-780 nm range were calculated using the following formulas (i) to (iii).

[0148] <Transmittance Ys after luminous sensitivity correction> ３８０～７８０ or Ys ４００～７００ , Parallel transmittance Yp after visibility correction ３８０～７８０ or Yp ４００～７００ , and the orthogonal transmittance Yc after luminous efficiency correction. ３８０～７８０ or Yc ４００～７００ > Transmittance Ys after luminous sensitivity correction ３８０～７８０ , Parallel transmittance Yp after visibility correction ３８０～７８０ and the orthogonal transmittance Yc after luminous sensitivity correction. ３８０～７８０ The values ​​are the transmittances obtained by correcting the luminous sensitivity according to JIS Z 8722:2009 for each of the single-element transmittance Ts, parallel-element transmittance Tp, and orthogonal-element transmittance Tc, which were determined at predetermined wavelength intervals dλ in the wavelength range of 380 to 780 nm. Specifically, the single-element transmittance Ts, parallel-element transmittance Tp, and orthogonal-element transmittance Tc were calculated by substituting them into the following formulas. In the formulas below, Pλ represents the spectral distribution of the standard light (C light source), and yλ represents the 2-degree field-of-view color matching function. When setting the wavelength range, it is necessary to set the spectral distribution and color matching function of the standard light used to the same wavelength range.

[0149] Formulas (1) to (3) show various transmittances (Ys) when the wavelength range is set to 380 to 780 nm. ３８０～７８０ Yp ３８０～７８０ ۀYc ３８０～７８０ This is the formula for calculating it.

[0150] Similar to Patent Documents 2, 4, and 9, the wavelength range was set to 400 to 700 nm and the evaluation was performed. Note that calculation formulas (4) to (6) are calculated according to calculation formulas (1) to (3), and various transmittances (Ys) are obtained when the wavelength range is set to 400 to 700 nm. ４００～７００ Yp ４００～７００ ۀYc ４００～７００ This is the formula for calculating it.

[0151] <Degree of polarization ρy> ３８０～７８０ or ρy ４００～７００ > For each measurement sample, the degree of polarization ρy ３８０～７８０ or ρy ４００～７００ The polarization degree ρy was calculated. ３８０～７８０ In formula (7), the polarization degree ρy ４００～７００ The calculation formula (8) is shown. The degree of polarization is the parallel transmittance Yp after luminous efficiency correction. ３８０～７８０ or Yp ４００～７００ and the orthogonal transmittance Yc after luminous sensitivity correction. ３８０～７８０ or Yc ４００～７００ The calculation was performed by substituting the values.

[0152] <Contrast> Calculation formula (9) or (10) plus parallel transmittance Yp after luminous efficiency correction. ３８０～７８０ or Yp ４００～７００ and the orthogonal transmittance Yc after luminous sensitivity correction. ３８０～７８０ or Yc ４００～７００ Substitute the following and adjust the contrast (CR ３８０～７８０ or CR ４００～７００ ) was obtained.

[0153] Table 1 shows the results of various transmittances and polarization performances, corrected for luminous efficiency, for each measurement sample prepared in Examples 1 to 6 and Comparative Examples 1 to 10, in the wavelength range of 400 to 700 nm.

[0154] The polarizers of Examples 1 to 6 shown in Table 1 exhibited higher performance than any of the polarizers of Comparative Examples 1 to 10. Specifically, each example of the present invention showed higher contrast than any of the four-color composites of Comparative Examples 1 to 5, and also than any of the three-color composites of Comparative Examples 6 to 10, when compared in the wavelength range of 400 to 700 nm.

[0155] Table 2 shows the results of various transmittances and polarization performances, corrected for luminous efficiency, for each measurement sample prepared in Examples 1 to 6 and Comparative Examples 11 and 12, in the wavelength range of 380 nm to 780 nm.

[0156] Table 2 shows that the polarizers of Examples 1 to 6 of the present invention exhibited higher performance than both of the polarizers of Comparative Examples 11 and 12. Specifically, each example of the present invention showed higher contrast than both of the three-color formulations of Comparative Examples 11 and 12 when compared in the wavelength range of 380 to 780 nm.

[0157] Comparing the contrast of Examples 1 to 6, it can be seen that the values ​​shown in Table 2 are up to approximately 2000 lower than those in Table 1. This result is influenced by the luminous efficiency correction range, as shown by calculation formulas (1) to (10). Furthermore, it is thought that the contrast of Comparative Examples 1 to 10 would similarly decrease if luminous efficiency correction were applied in the range of 380 to 780 nm.

[0158] Table 3 shows the polarization performance results when the single-element transmittance (Ys) after luminous efficiency correction at 380-780 nm was standardized for each measurement sample in Examples 1-6 and Comparative Examples 13 and 14.

[0159] Table 3 shows that the polarizers of Examples 1 to 6 of the present invention exhibited higher polarization performance than the polarizers of Comparative Examples 13 and 14. When comparing Comparative Examples 13 and 14, which were prepared by adjusting Comparative Example 6, which has a Ys close to that of each example, the highest degree of polarization, and good contrast among the comparative examples listed in Table 1, and Comparative Example 11, which has the highest degree of polarization and good contrast among the comparative examples listed in Table 2, to a single transmittance (Ys) of approximately 39% to 40%, similar to that of each example, it was found that each example had higher contrast. Furthermore, by using compounds A and B in combination, the polarizers of Examples 1 to 6 have lower orthogonal transmittance values ​​above 700 nm, particularly at 730 nm, which is 0 to 1% or less, compared to Comparative Examples 13 and 14, indicating improved polarization performance on the longer wavelength side. In other words, it was revealed that the polarizers of each example have high polarization and high contrast over a wide range of 380 nm to 780 nm, and have almost no light leakage in the long wavelength range.

[0160] Furthermore, after 500 hours under ambient temperature conditions of 105°C, and after 500 hours under ambient temperature conditions of 85°C and relative humidity conditions of 85%, the polarizing plates of Examples 1 to 6 showed almost no decrease in contrast or polarization degree, demonstrating long-term durability even under high temperature and high humidity conditions.

[0161] The present invention can provide polarizing films, polarizing plates, and optical components having optical properties equivalent to or better than those of conventional products. The polarizing film or polarizing plate of the present invention can be used in liquid crystal projectors, calculators, watches, laptop computers, word processors, liquid crystal televisions, polarizing lenses, polarizing glasses, head-up displays, car navigation systems, OLEDs, and display devices used in indoor and outdoor measuring instruments and displays, or similar optical devices. A display device in which the polarizing film or polarizing plate of the present invention is used in an OLED is one embodiment of the present invention. Furthermore, as one particularly preferred application of the polarizing plate of the present invention, a display device equipped with the polarizing film or polarizing plate of the present invention can not only provide a high degree of polarization, i.e., contrast, in the visible light region, particularly in the wavelength region of 380 to 780 nm, but also high durability. This durability means that the display device can be provided in which there is almost no decrease in the degree of polarization and contrast even in an environment of 85°C with an ambient temperature of 105°C or a relative humidity of 85%. Particularly preferred applications include in-vehicle displays, liquid crystal projectors, head-up displays, and outdoor displays, which can be suitably used in fields where not only high contrast but also heat resistance, humidity resistance, and light resistance are required.

Claims

A polarizing film containing a substrate, wherein the substrate contains an azo compound or a salt thereof represented by the following formula (1) (compound A) and an azo compound or a salt thereof represented by the following formula (2) (compound B). (In formula (1), X １ Q represents an optionally substituted amino group, or an optionally substituted phenylamino group, an optionally substituted naphthylamino group, an optionally substituted benzoylamino group, or an optionally substituted naphthotriazole group. １ and R １ ~R ４ Each of these independently represents an arbitrary substituent, and m represents an integer from 1 to 3. (In formula (2), X ２ represents an amino group which may have a substituent, or a phenylamino group which may have a substituent, a naphthylamino group which may have a substituent, a benzoylamino group which may have a substituent, or a naphthotriazole group which may have a substituent; Q ２ , Q ３ , and R ５ to R ８ each independently represent an arbitrary substituent; A represents a sulfo group or a carboxy group; and n represents an integer of 0 to 3.) In formula (1), Q １ However, C has a hydrogen atom and a sulfo group. １ ~C ４ It is an alkoxy group or a carboxyl group, X １ However, an unsubstituted amino group; one or two C １ ~C ４ amino group having an alkyl group; unsubstituted phenylamino group; or C １ ~C ４ C having an alkoxy group and 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 alkyl groups, carboxyl groups, hydroxyl groups, sulfo groups, and amino groups. In formula (2), Q ２ and Q ３ Each of them independently has a hydrogen atom and a sulfo group C １ ~C ４ It is an alkoxy group or a carboxyl group, X ２ However, an unsubstituted amino group; one or two C １ ~C ４ amino group having an alkyl group; unsubstituted phenylamino group; or C １ ~C ４ C having an alkoxy group and 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 alkyl groups, carboxyl groups, hydroxyl groups, sulfol groups, and amino groups. The polarizing film according to claim 1. 　 The polarizing film according to claim 1, wherein the compound represented by formula (1) is represented by the following formula (3), and the compound represented by formula (2) is represented by the following formula (4). (In formula (3), R １ ~R ４ Each of these independently represents an arbitrary substituent, and m represents an integer from 1 to 3. (In formula (4), R ５ ~R ８ Each of these independently represents an arbitrary substituent, R ９ (where represents a hydrogen or methoxy group, A represents a sulfo group or carboxyl group, and n represents an integer from 0 to 3.) In formula (3), R １ ~R ４ Each of them independently forms a hydrogen atom, C １ ~C ４ alkyl group, C １ ~C ４ C having an alkoxy group and a sulfo group １ ~C ４ It is an alkoxy group, and in formula (4), R ５ ~R ８ Each of them independently forms a hydrogen atom, C １ ~C ４ alkyl group, C １ ~C ４ C having an alkoxy group and a sulfo group １ ~C ４ The polarizing film according to claim 3, wherein the group is an alkoxy group, A is a sulfo group or a carboxyl group, and n is an integer of 1 or 2. 　 The polarizing film according to claim 1, comprising one or more dichroic dyes other than the azo compound or salt thereof described in claim 1. 　 The polarizing film according to claim 1, wherein the single-layer transmittance (Ys) after luminous efficiency correction in the 380 nm to 780 nm range is 39% or more, and the orthogonal transmittance (Tc) at 730 nm is 1% or less. 　 The polarizing film according to claim 1, characterized in that the substrate according to claim 1 is a film made of a polyvinyl alcohol-based resin. 　 A polarizing plate comprising a transparent protective film provided on one or both sides of the polarizing film according to any one of claims 1 to 7. 　 A display device comprising the polarizing plate according to claim 8.

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