CN108603039B - Azo compound, polarizing element and polarizing plate using the same, and display device - Google Patents

Abstract

The present invention provides a polarizing element and a polarizing plate having excellent polarizing performance and contrast, a display device having excellent contrast, and a novel azo compound useful in the polarizing element and the polarizing plate and the display device. The azo compound is represented by the following general formula (1) (wherein Ab₁Represents a substituted phenyl group or a substituted naphthyl group, Rb₁To Rb₅Each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a sulfonic acid group, or an alkoxy group having 1 to 4 carbon atoms and having a sulfonic acid group, Xb₁Represents an amino group which may have a substituent, a phenylamino group which may have a substituent, a benzoylamino group which may have a substituent, a phenylazo group which may have a substituent, or a naphthotriazole group which may have a substituent). The polarizing plate and the polarizing plate comprise a substrate and the azo compound. The display device is provided with the polarizing component or the polarizing plate.

Description

Azo compound, polarizing element and polarizing plate using the same, and display equipment

technical field

The present invention relates to a novel azo compound, a polarizing element and a polarizing plate with a high degree of polarization using the azo compound, and a display device.

Background technique

The polarizer is usually produced by directional adsorption of iodine or a dichroic dye, which is a dichroic dye, on a polyvinyl alcohol resin film. A polarizing plate can be produced by bonding a protective film made of triacetyl cellulose or the like to at least one surface of the polarizing element via an adhesive layer. Polarizing plate, which can be used in display equipment, etc. A polarizing plate using iodine as a dichroic dye is called an iodine-based polarizing plate, while a polarizing plate using a dichroic dye as a dichroic dye is called a dye-based polarizing plate. Among these, dye-based polarizing plates are characterized by high heat resistance, high humidity and heat durability, and high stability, and high color selectivity due to the preparation of dichroic dyes.

In Patent Documents 1 to 4 and Non-Patent Documents 1 and 2, dye-based polarizers containing azo compounds are disclosed.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Laid-Open No. 11-218611

Patent Document 2: Japanese Patent No. 4162334

Patent Document 3: Japanese Patent No. 4360100

Patent Document 4: Japanese Patent Laid-Open No. 2004-075719.

Non-patent literature

Non-Patent Document 1: Toyo Hosoda, "Dye Chemistry", Gihodo Publishing Co., Ltd., 1957, p. 621

Non-Patent Document 2: Supervised by Masahiro Irie, "Application of Functional Pigments" (1st Edition), CMC Publishing Co., Ltd., June 2002, pp. 98-104.

SUMMARY OF THE INVENTION

(The problem to be solved by the invention)

However, the conventional azo compound-containing polarizers described in Patent Documents 1 to 4 and Non-Patent Documents 1 and 2 have poor polarization performance and contrast, and cannot sufficiently respond to recent demands for high-precision display orientation.

One of the objectives of the present invention is to provide polarizing components and polarizing plates with excellent polarization performance and contrast, display devices with excellent contrast, and novel azo compounds that can be used in polarizing components, polarizing plates and display devices.

(the way to solve the problem)

As a result of intensive research to solve the above-mentioned problems, the present inventors have found that a novel azo compound as a dichroic dye constituting a polarizing element and a polarizing plate can be utilized, and that excellent polarized light can be realized by using the azo compound. The present invention is achieved by providing a polarizing element and a polarizing plate with performance and contrast, as well as a display device with excellent contrast.

That is, the present invention is related to the following:

(1) An azo compound which is an azo compound represented by the following general formula (1) or a salt thereof.

(In the formula, Ab ₁ represents a substituted phenyl group or a substituted naphthyl group, and Rb ₁ to Rb ₅ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. , a sulfonic acid group, or an alkoxy group having a sulfonic acid group with 1 to 4 carbon atoms, Xb ₁ represents an amino group that may have a substituent, a phenylamino group that may have a substituent, a benzoylamino group that may have a substituent, optionally substituted phenylazo, or optionally substituted naphthotriazolyl);

(2) An azo compound which is the azo compound described in (1) and is an azo compound represented by the following general formula (2) or a salt thereof.

(in the formula, Ab ₁ represents a phenyl group having one or two substituents selected from the group consisting of a sulfonic acid group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms, Or a naphthyl group with 2 or 3 substituents selected from the group consisting of a sulfonic acid group, a hydroxyl group and an alkoxy group with a carbon number of 1 to 4 having a sulfonic acid group; Rb ₁ to Rb ₅ each independently represent a hydrogen atom , an alkyl group with 1 to 4 carbon atoms, an alkoxy group with ₁ to 4 carbon atoms or an alkoxy group with a sulfonic acid group with 1 to 4 carbon atoms; A phenylamino group with one or two substituents in the group consisting of an acid group, an amino group and an alkylamino group having 1 to 4 carbon atoms, and may have one selected from the group consisting of a hydroxyl group, an amino group and a carboxyethylamino group The benzoylamino group of the substituent may have 1 to 3 substituents selected from the group consisting of hydroxyl, alkyl with 1 to 4 carbons, alkoxy with 1 to 4 carbons, amino and carboxyethylamino phenylazo, or naphthotriazolyl substituted with 1 or 2 sulfonic acid groups);

(3) An azo compound, which is the azo compound described in (1) or (2), wherein Xb ₁ in the aforementioned general formula (1) or (2) may have a group selected from methyl, methoxy phenylamino group with 1 or 2 substituents in the group consisting of sulfonic acid group, sulfonic acid group, amino group and alkylamino group with 1 to 4 carbon atoms;

(4) A polarizing component, comprising a base material and the azo compound described in any one of (1) to (3);

(5) A polarizing element, which is the polarizing element described in (4), further comprising an azo compound represented by the following general formula (3) or a salt thereof,

(in the formula, Ar ₁ represents a substituted phenyl group or a substituted naphthyl group, and Rr ₁ to Rr ₆ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. or an alkoxy group having a carbon number of 1 to 4 with a sulfonic acid group, Xr ₁ represents an amino group which may have a substituent, a phenylamino group which may have a substituent, a benzoylamino group which may have a substituent, Phenylazo or naphthotriazolyl which may have substituents, m and n independently represent 0 or 1);

(6) A polarizing element, which is the polarizing element described in (4) or (5), further comprising an azo compound represented by the following general formula (4) or a salt thereof,

(in the formula, Ay ₁ represents a sulfonic acid group, a carboxyl group, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and Ry ₁ to Ry ₄ independently represent a hydrogen atom, a sulfonic acid group, a carbon alkyl of 1 to 4 or alkoxy of 1 to 4 carbons, p represents an integer of 1 to 3);

(7) A polarizing element according to (5), wherein the azo compound represented by the aforementioned general formula (3) or a salt thereof is an azo compound represented by the following general formula (5) or a salt thereof ,

(in the formula, Ar ₁ represents a phenyl group having one or two substituents selected from the group consisting of a sulfonic acid group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms, Or a naphthyl group with 2 or 3 substituents selected from the group consisting of a sulfonic acid group, a hydroxyl group and an alkoxy group having a carbon number of 1 to 4 with a sulfonic acid group; Rr ₁ to Rr ₆ each independently represent a hydrogen atom , alkyl with 1 to 4 carbons, alkoxy with 1 to 4 carbons or alkoxy with ₁ to 4 carbons with sulfonic acid group; The phenylamino group with one or two substituents in the group consisting of an acid group, an amino group, and an alkylamino group having 1 to 4 carbon atoms may have 1 selected from the group consisting of a hydroxyl group, an amino group, and a carboxyethylamino group. The benzoylamino group of one substituent may have 1 to 3 substitutions selected from the group consisting of hydroxyl, alkyl with 1 to 4 carbons, alkoxy with 1 to 4 carbons, amino and carboxyethylamino phenylazo of the base, or naphthotriazolyl substituted with 1 or 2 sulfonic acid groups; m and n independently represent 0 or 1);

(8) A polarizing component, which is the polarizing component described in (5) or (7), wherein one of Rr ₅ and Rr ₆ in the aforementioned general formula (3) or (5) is a carbon number of 1 to 4 alkoxy, and the other is an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms;

(9) A polarizing component, which is the polarizing component described in (5) or (7), wherein Xr ₁ in the aforementioned general formula (3) or (5) may have a group selected from methyl, methoxy, A phenylamino group with one or two substituents in the group consisting of a sulfonic acid group, an amino group and an alkylamino group having 1 to 4 carbon atoms, or a phenylamino group selected from the group consisting of a hydroxyl group, an amino group and a carboxyethylamino group 1 substituent benzoylamino;

(10) A polarizing component, which is the polarizing component described in (6), wherein Ay ₁ in the general formula (4) is a carboxyl group or a sulfonic acid group;

(11) A polarizing component, which is the polarizing component according to any one of (4) to (10), wherein the substrate is a film formed of polyvinyl alcohol or a derivative thereof;

(12) A polarizing plate comprising the polarizing assembly described in any one of (4) to (11), and a transparent protective layer provided on at least one side of the polarizing assembly;

(13) A display device including the polarizing assembly according to any one of (4) to (11), or the polarizing plate according to (12).

(effect of invention)

The present invention can provide a polarizing element and a polarizing plate with excellent polarization performance and contrast, a display device with excellent contrast, and a novel azo compound that can be used in the polarizing element, polarizing plate and display device.

Detailed ways

Hereinafter, the present invention will be described in detail.

[novel azo compound]

The azo compound of the present invention is an azo compound represented by the following general formula (1) or a salt thereof. The azo compound of the present invention is a water-soluble dye that functions as a dye, generally called a dichroic dye.

In the general formula (1), Ab ₁ represents a substituted phenyl group or a substituted naphthyl group, and Rb ₁ to Rb ₅ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkyl group having 1 to 4 carbon atoms. An alkoxy group, a sulfonic acid group or an alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms, Xb ₁ represents an amino group which may have a substituent (excluding phenyl and benzoyl), a phenylamino which may have a substituent , an optionally substituted benzoylamino group, an optionally substituted phenylazo group, or an optionally substituted naphthotriazolyl group.

The azo compound represented by the aforementioned general formula (1) is preferably an azo compound represented by the following general formula (2). Thereby, the polarizing performance of the polarizing element using the azo compound represented by General formula (1) can be improved more.

(In the formula, Ab ₁ , Rb ₁ to Rb ₅ and Xb ₁ have the same meanings as in the general formula (1))

Ab ₁ in the aforementioned general formula (1) or (2) represents a substituted phenyl group or a substituted naphthyl group, but has a sulfonic acid group, a carboxyl group, and an alkyl group having 1 to 4 carbon atoms. phenyl group with one or two substituents in the group consisting of alkoxy groups with 1 to 4 carbon atoms, or alkoxy groups with 1 to 4 carbon atoms selected from the group consisting of sulfonic acid groups, hydroxyl groups and sulfonic acid groups Naphthyl groups of 2 or 3 substituents in the formed group are preferred.

When Ab ₁ in the aforementioned general formula (1) or (2) is a substituted phenyl group, it is preferable to have at least one sulfonic acid group or carboxyl group as the substituent. When Ab ₁ is a phenyl group having two or more substituents, among these substituents, (part of) at least one substituent is a sulfonic acid group or a carboxyl group, and the other substituents are a sulfonic acid group, a carboxyl group, a carbon number 1 An alkyl group of to 4, an alkoxy group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms having a sulfonic acid group, a nitro group, an amino group, an acetylamino group or an alkylamino group of 1 to 4 carbon atoms is Preferred. The substituent on the phenyl group is more preferably a sulfonic acid group, an alkyl group with 1 to 4 carbon atoms, an alkoxy group with a carbon number of 1 to 4, a nitro group, an amino group or a carboxyl group, and a sulfonic acid group, methyl group, methyl group Oxy, ethoxy or carboxyl groups are particularly preferred. The number of substituents on the phenyl group is preferably two. The substitution position of the substituent on the phenyl group is not particularly limited, but when the number of the substituent group on the phenyl group is two, a combination of the 2-position and the 4-position is preferable.

When Ab ₁ in the aforementioned general formula (1) or (2) is a naphthyl group having a substituent, it is preferable to have at least one sulfonic acid group as the substituent. When Ab ₁ is a naphthyl group having two or more substituents, among these substituents, (part of) at least one substituent is a sulfonic acid group, and the other substituents are a sulfonic acid group, a hydroxyl group, a carboxyl group or a sulfonic acid group An alkoxy group having 1 to 4 carbon atoms in the acid group is preferable. When the number of substituents on the naphthyl group is 2, the combination of the substitution positions of these substituents is preferably the combination of the 4-position and the 8-position or the combination of the 6-position and the 8-position, and the combination of the 6-position and the 8-position is preferred. Combinations of position and 8-position are particularly preferred. When the number of the substituents on the naphthyl group is three, the combination of the substitution positions of these substituents is particularly preferably a combination of the 1-position and the 3-position and the 6-position.

The C1-C4 alkoxy group having a sulfonic acid group as the substituent on the phenyl group or the naphthyl group in Ab ₁ is preferably a C1-C4 linear alkoxy group having a sulfonic acid group . In the C1-C4 alkoxy group having a sulfonic acid group, the substitution position of the sulfonic acid group is preferably an alkoxy terminal. As the alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms, 3-sulfopropoxy or 4-sulfobutoxy is more preferable, and 3-sulfopropoxy is particularly preferable.

Although Xb ₁ in the general formula (1) or (2) represents an optionally substituted amino group (excluding phenyl and benzoyl), an optionally substituted phenylamino group, and an optionally substituted benzoylamino group , a phenylazo group that may have a substituent, or a naphthotriazolyl that may have a substituent; but preferably: may have a group selected from methyl, methoxy, sulfonic acid, amino and carbon number 1 to 4 A phenylamino group with one or two substituents in the group consisting of alkylamino may have a benzoylamino group with one substituent selected from the group consisting of hydroxyl, amino and carboxyethylamino, and may have an optional phenylazo with 1 to 3 substituents selected from the group consisting of hydroxyl, alkyl having 1 to 4 carbons, alkoxy having 1 to 4 carbons, amino and carboxyethylamino, or 1 to 3 substituents Or a naphthotriazolyl group substituted with 2 sulfonic acid groups; more preferably: may have 1 selected from the group consisting of methyl, methoxy, sulfonic acid, amino and alkylamino groups with 1 to 4 carbon atoms Or a phenylamino group with two substituents, or a benzoylamino group with one substituent selected from the group consisting of hydroxyl, amino and carboxyethylamino; A phenylamino group with one or two substituents in the group consisting of an oxy group, a sulfonic acid group, an amino group and an alkylamino group having 1 to 4 carbon atoms. The substitution position of the substituent is not particularly limited, but when Xb ₁ is a phenylamino group having one substituent, a benzoylamino group having one substituent, or a phenylazo group having one substituent , the para position is especially preferred.

Rb ₁ to Rb ₅ in the general formula (1) or (2) each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a carbon number having a sulfonic acid group 1 to 4 alkoxy groups, preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and more preferably a hydrogen atom, a methyl group or a methoxy group. And in order to improve the optical properties, the combination of the substitution positions of Rb ₁ and Rb ₂ and the combination of the substitution positions of Rb ₃ and Rb ₄ are independently the combination of the 2-position and the 6-position, and the combination of the 2-position and the 5-position. The combination or the combination of the 3-position and the 5-position is preferred, and the combination of the 2-position and the 5-position is more preferred. The substitution position of Rb ₅ is preferably the 2-position or the 3-position, and more preferably the 2-position. When the combination of the substitution positions of Rb ₁ and Rb ₂ and the combination of the substitution positions of Rb ₃ and Rb ₄ are each independently and at least one of them is a methoxy group, the combination of the 2-position and the 6-position, the 2-position and the 5-position A combination of positions or a combination of 3-position and 5-position is preferred, and a combination of 2-position and 5-position is more preferred.

The method for producing the azo compound represented by the aforementioned general formula (1) will be described below. Since the azo compound represented by the aforementioned general formula (1) can be produced by the same production method as the known production method, the production method of the azo compound represented by the aforementioned general formula (1) is not limited to the one described here. Manufacturing method. For example, according to the production method of a general azo dye as described in Non-Patent Document 1, the azo compound represented by the aforementioned general formula (1) can be easily produced by performing well-known diazotization and coupling.

The azo compound represented by the aforementioned general formula (1) can be produced as follows. First, a monoazoamino compound represented by the following general formula (6) is obtained.

(In the formula, Ab ₁ , Rb ₁ and Rb ₂ have the same meanings as in the aforementioned general formulae (1) and (2))

In the monoazoamino compound represented by the aforementioned general formula (6), when Ab ₁ is a phenyl group having at least one sulfonic acid group, well-known aromatic amines represented by the following general formula (7) can be used. Method The sulfonic alkoxyaniline acids obtained by alkylation of the sulfonic acid group are obtained by diazotization and primary coupling with anilines represented by the following general formula (8).

(in the formula, one of Rb ₁₁ and Rb ₁₂ represents a sulfonic acid group or a carboxyl group, and the other represents a sulfonic acid group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a sulfonic acid group alkoxy, nitro, amino, acetylamino, or alkylamino having 1 to 4 carbon atoms, or the compound represented by the general formula (7) can be 4-aminobenzenesulfonic acid , 3-aminobenzenesulfonic acid, 2-aminobenzenesulfonic acid, or 4-aminobenzoic acid)

(In the formula, Rb ₁ and Rb ₂ have the same meanings as in the aforementioned general formulae (1) and (2))

In the monoazoamino compound represented by the aforementioned general formula (6), when Ab ₁ is a naphthyl group having at least one sulfonic acid group, a naphthylamine sulfonic acid represented by the following general formula (9) or Amino naphthol sulfonic acids are diazotized with sulfoalkoxy naphthyl amine sulfonic acids obtained by alkylation of sulfonic acid groups using a known method, and the anilines represented by the aforementioned general formula (8) are subjected to primary diazotization. coupled.

(wherein, Rb ₁₃ represents a hydrogen atom, a hydroxyl group, a carboxyl group, a sulfonic acid group, a tosylate-esterified hydroxyl group, an amino group, a substituted amino group, a nitro group, a substituted amide group, or a sulfonic acid group having 1 to 4 carbon atoms. alkoxy, q represents an integer from 1 to 3)

Next, the monoazoamino compound represented by the aforementioned general formula (6) is diazotized to couple with anilines represented by the following general formula (10) twice to obtain a bis(2) compound represented by the following general formula (11). Azoamino compounds.

(In the formula, Rb ₃ and Rb ₄ have the same meanings as in the aforementioned general formula (1) and (2))

(In the formula, Ab ₁ , Rb ₁ , Rb ₂ , Rb ₃ and Rb ₄ have the same meanings as in the aforementioned general formula (1) and (2))

Next, the bisazoamino compound represented by the general formula (11) is diazotized to couple with anilines represented by the following general formula (12) three times to obtain a compound represented by the following general formula (13). Trisazoamino compound.

(In the formula, Ab ₁ and Rb ₁ to Rb ₅ have the same meanings as in the general formulae (1) and (2))

Next, the trisazoamino compound represented by the aforementioned general formula (13) is diazotized by a known method to couple with the naphthols represented by the following general formula (14) four times to obtain the following general formula ( The tetrazo compound represented by 15).

(In the formula, Xb ₁ has the same meaning as in the aforementioned general formulae (1) and (2))

(In the formula, Ab ₁ , Rb ₁ to Rb ₅ and Xb ₁ have the same meanings as in the aforementioned general formulae (1) and (2))

In the tetrazo compound represented by the aforementioned general formula (15), a copper complex salt compound formed by copper sulfate and at least one selected from the group consisting of ammonia water, amino alcohol and hexamethylenetetramine is added, and the It is preferable to carry out the copperization reaction at 85°C to 95°C, thereby obtaining the copper complex salted azo compound represented by the general formula (1) or the general formula (2).

The diazotization step in the above-mentioned synthesis can be by the forward method of mixing nitrites such as sodium nitrite in the aqueous solution of mineral acids such as hydrochloric acid and sulfuric acid of the diazo component or the suspension, or by adding the diazo component in advance. The neutral or weakly alkaline aqueous solution is added with nitrite and mixed with mineral acid by the reverse method. The temperature of the diazotization is suitably -10 to 40°C. In addition, the coupling step of diazonium compounds and anilines is to mix acidic aqueous solutions such as hydrochloric acid and acetic acid with each of the above-mentioned diazonium liquids (aqueous solutions or suspensions of diazonium compounds) at a temperature of -10 to 40°C and a pH of 2 to 7. carried out under acidic conditions.

The monoazoamino compound, bisazoamino compound and triazoamino compound obtained by coupling can be taken out directly or by acid precipitation or salt precipitation, then filtered and taken out, or the solution or suspension can be maintained directly. Go to the next step. When the diazonium salt is poorly soluble and forms a suspension, it can also be filtered into a press cake and used in the next coupling step.

Four coupling reactions of the diazonium compound of the trisazoamino compound represented by the general formula (13) and the naphthols represented by the general formula (14) at a temperature of -10 to 40°C and a neutral to 10 pH of under alkaline conditions. After completion of the reaction, it was taken out by precipitation by salting and filtration. In addition, when purification is necessary, it is sufficient to repeat salting out or to precipitate out of water using an organic solvent. Examples of the organic solvent used for purification include alcohols such as methanol and ethanol; and water-soluble organic solvents such as ketones such as acetone.

The aromatic amines represented by the general formula (7) are starting materials (raw material compounds) for synthesizing the azo compounds represented by the aforementioned general formula (1) when Ab ₁ is a substituted phenyl group, wherein the general formula ( Rb ₁₁ and Rb ₁₂ of the aromatic amines represented by 7) include a hydrogen atom, a sulfonic acid group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a sulfonic acid group. The acid group is an alkoxy group having 1 to 4 carbon atoms, a naphthotriazolyl group substituted with a sulfonic acid group or the like, a nitro group, an amino group, an acetylamino group, or an alkylamino group having 1 to 4 carbon atoms. Rb ₁₁ and Rb ₁₂ are preferably each independently a hydrogen atom, a sulfonic acid group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and at least 1 of Rb ₁₁ and Rb ₁₂ is preferred. It is more preferable that each is a sulfonic acid group, and the number of substituents of Rb ₁₁ and Rb ₁₂ is 2 (that is, both Rb ₁₁ and Rb ₁₂ are not hydrogen atoms). The alkoxy group having 1 to 4 carbon atoms having a sulfonic acid group is preferably a linear alkoxy group having 1 to 4 carbon atoms having a sulfonic acid group. In the alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms, the substitution position of the sulfonic acid group is preferably an alkoxy terminal. The alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms is more preferably 3-sulfopropoxy or 4-sulfobutoxy.

Examples of the aromatic amines represented by the general formula (7) include 4-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid, 2-aminobenzenesulfonic acid, 4-aminobenzoic acid, and 2-amino-5-methane benzenesulfonic acid, 2-amino-5-methoxybenzenesulfonic acid, 4-amino-2-methylbenzenesulfonic acid, 3-amino-4-methoxybenzenesulfonic acid, 2-amino-4-sulfonic acid Acid benzoic acid, 2-amino-5-sulfobenzoic acid, etc., 5-aminoisophthalic acid, 2-amino-5-nitrobenzenesulfonic acid, 5-acetamide-2-aminobenzenesulfonic acid, 2-Amino-5-(3-sulfopropoxy)benzenesulfonic acid, 4-aminobenzene-1,3-disulfonic acid, 2-aminobenzene-1,4-disulfonic acid, etc., and 4-aminobenzene-1,4-disulfonic acid, etc. - Aminobenzenesulfonic acid, 2-amino-5-methoxybenzenesulfonic acid, 4-amino-2-methylbenzenesulfonic acid, 4-aminobenzene-1,3-disulfonic acid are especially preferred. In addition, the aromatic amines represented by the general formula (7) may have a naphthotriazolyl group as a substituent on the phenyl group. The aforementioned naphthotriazolyl groups include 6,8-disulfonaphthotriazolyl, 7,9-disulfonaphthotriazolyl, 7-sulfonaphthotriazolyl, 5 -Sulfonyl naphthotriazolyl, etc. In this case, the naphthotriazolyl group is particularly preferred at the para position to the phenyl group.

The naphthylamine sulfonic acids represented by the aforementioned general formula (9) are starting materials (raw material compounds) for synthesizing the azo compounds represented by the aforementioned general formula (1) when Ab ₁ is a substituted naphthyl group, wherein the aforementioned Rb ₁₃ of the naphthylamine sulfonic acids represented by the general formula (9) is a hydrogen atom, a hydroxyl group, a carboxyl group, a sulfonic acid group, a tosylate-esterified hydroxyl group, an amino group, a substituted amino group, a nitro group, a substituted amido group, or a sulfonic acid group. The alkoxy group having 1 to 4 carbon atoms in the acid group is preferably a hydrogen atom, a sulfonic acid group, and an alkoxy group having 1 to 4 carbon atoms having a sulfonic acid group. Moreover, Rb ₁₃ is preferably a hydrogen atom, a hydroxyl group, a carboxyl group, or a lower alkoxy group having a sulfonic acid group. The alkoxy group having 1 to 4 carbon atoms having a sulfonic acid group is preferably a linear alkoxy group having 1 to 4 carbon atoms having a sulfonic acid group. In the C1-C4 alkoxy group having a sulfonic acid group, the substitution position of the sulfonic acid group is preferably an alkoxy terminal. The alkoxy group having 1 to 4 carbon atoms having a sulfonic acid group is preferably 3-sulfopropoxy or 4-sulfobutoxy. In the naphthylamine sulfonic acids represented by the aforementioned general formula (9), the substitution position of the sulfonic acid group may be on any benzene nucleus of the naphthalene ring. When the number q of the sulfonic acid group is 1, the substitution position of the sulfonic acid group is preferably any one of the 1-position, the 3-position and the 6-position, and when the number q of the sulfonic acid group is 2 or 3 The combination of the substitution positions of the sulfonic acid group is preferably a combination of 2 or 3 selected from the group consisting of 1-position, 3-position, 6-position and 7-position.

The naphthylamine sulfonic acids represented by the aforementioned general formula (9) include, for example, 2-aminonaphthalene-1-sulfonic acid, 8-aminonaphthalene-1-sulfonic acid, 5-aminonaphthalene-1-sulfonic acid, 5-aminonaphthalene-2-sulfonic acid, 8-aminonaphthalene-2-sulfonic acid, 3-aminonaphthalene-1-sulfonic acid, 6-aminonaphthalene-2-sulfonic acid, 4-aminonaphthalene-1-sulfonic acid, 7-aminonaphthalene-1,3-disulfonic acid, 6-aminonaphthalene-1,3-disulfonic acid, 3-amino-7-nitronaphthalene-1,5-disulfonic acid, 4-aminonaphthalene-1 ,6-disulfonic acid, 4-aminonaphthalene-1,5-disulfonic acid, 5-aminonaphthalene-1,3-disulfonic acid, 3-aminonaphthalene-1,5-disulfonic acid, 2-aminonaphthalene -1,5-disulfonic acid, 7-aminonaphthalene-1,3,6-trisulfonic acid, 7-aminonaphthalene-1,3,5-trisulfonic acid, 8-aminonaphthalene-1,3,6- Trisulfonic acid, 5-aminonaphthalene-1,3,6-trisulfonic acid, 7-amino-3-(3-sulfopropoxy)naphthalene-1-sulfonic acid, 7-amino-3-(4 - Sulfobutoxy)naphthalene-1-sulfonic acid, 7-amino-4-(3-sulfopropoxy)naphthalene-2-sulfonic acid, 7-amino-4-(4-sulfonic acid) Butoxy)naphthalene-2-sulfonic acid, 6-amino-4-(3-sulfopropoxy)naphthalene-2-sulfonic acid, 6-amino-4-(4-sulfobutoxy) Naphthalene-2-sulfonic acid, 2-amino-5-(3-sulfopropoxy)naphthalene-1,7-disulfonic acid, 6-amino-4-(3-sulfopropoxy)naphthalene -2,7-disulfonic acid or 7-amino-3-(3-sulfopropoxy)naphthalene-1,5-disulfonic acid, etc., but with 7-aminonaphthalene-1,3-disulfonic acid , 6-aminonaphthalene-1,3-disulfonic acid, 7-aminonaphthalene-1,3,6-trisulfonic acid, 7-amino-4-(3-sulfopropoxy)naphthalene-2-sulfonic acid Acid, 6-amino-4-(3-sulfopropoxy)naphthalene-2-sulfonic acid is preferred, and 7-aminonaphthalene-1,3-disulfonic acid, 7-aminonaphthalene-1,3 ,6-trisulfonic acid and 7-amino-4-(3-sulfopropoxy)naphthalene-2-sulfonic acid are especially preferred.

Rb ₁ and Rb ₂ possessed by the anilines represented by the aforementioned general formula (8), which are primary coupling components, and Rb ₃ and Rb ₄ possessed by the anilines represented by the aforementioned general formula (10), which are secondary coupling components, although each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms, but preferably a hydrogen atom, methyl group, methyl group Oxy group, 3-sulfonylpropoxy group, 4-sulfonylbutoxy group, more preferably hydrogen atom, methyl group, methoxy group. The combination of the substitution positions of Rb ₁ and Rb ₂ and the combination of the substitution positions of Rb ₃ and Rb ₄ , respectively independently and relative to the combination of the 2-position and the 6-position of the amino group, the combination of the 2-position and the 5-position, Or a combination of 3-position and 5-position is preferable, and a combination of 2-position and 5-position is more preferable. 3-( 2-Amino-4-methylphenoxy)propane-1-sulfonic acid, 3-(2-aminophenoxy)propane-1-sulfonic acid, 3-(2-amino-4-methylphenoxy) ) butane-1-sulfonic acid, etc. Anilines other than the above, which can be used as the anilines represented by the aforementioned general formula (8) and the anilines represented by the aforementioned general formula (10), include, for example, 2,5-dimethylaniline and 2,5-diethylaniline. aniline, 2-methoxy-5-methylaniline, 2,5-dimethoxyaniline, 3,5-dimethylaniline, 2,6-dimethylaniline or 3,5-dimethoxyaniline aniline, etc. These anilines may be anilines in which the amino group is protected by a protecting group. Examples of the aforementioned protecting group include its ω-methanesulfonic acid group. The anilines represented by the aforementioned general formula (8) used for the primary coupling and the anilines represented by the aforementioned general formula (10) used for the secondary coupling may be the same or different.

The anilines having a methoxy group represented by the aforementioned general formula (12), which are tertiary coupling components, may be any anilines having a methoxy group at the ortho-position with respect to the amino group, but 2,5-dimethoxy Aniline, 2-methoxyaniline, and 2-methoxy-5-methylaniline are preferred.

Substituent Xb ₁ which the naphthols represented by the aforementioned general formula (14) belonging to the quaternary coupling component has an amino group which may have a substituent (excluding a phenyl group and a benzoyl group), a phenylamino group which may have a substituent, A benzoylamino group that may have a substituent, a phenylazo group that may have a substituent, or a naphthotriazolyl group that may have a substituent; but preferably: may have a group selected from methyl, methoxy, sulfonic acid, A phenylamino group with one or two substituents in the group consisting of an amino group and an alkylamino group having 1 to 4 carbon atoms may have one substituent selected from the group consisting of a hydroxyl group, an amino group and a carboxyethylamino group. Benzoylamino, a phenyl group having 1 to 3 substituents selected from the group consisting of hydroxy, alkyl with 1 to 4 carbons, alkoxy with 1 to 4 carbons, amino and carboxyethylamino Azo group, or naphthotriazolyl group substituted with 1 or 2 sulfonic acid groups; more preferably: may have selected from methyl group, methoxy group, sulfonic acid group, amino group and alkyl group with 1 to 4 carbon atoms A phenylamino group with 1 or 2 substituents in the group formed by amino, or a benzoylamino group with 1 substituent selected from the group formed by hydroxyl, amino and carboxyethylamino; and more preferably: A phenylamino group which may have one or two substituents selected from the group consisting of a methyl group, a methoxy group, a sulfonic acid group, an amino group, and an alkylamino group having 1 to 4 carbon atoms. When Xb ₁ is a phenylamino group having one substituent, a benzoylamino group having one substituent, or a phenylazo group having one substituent, the substitution position of the substituent is not particularly limited, but Xb When ₁ is a phenylamino group having one substituent, a benzoylamino group having one substituent, or a phenylazo group having one substituent, the para-position is particularly preferable.

The azo compound of the present invention can exist in the form of the free acid represented by the aforementioned general formula (1) or in the form of a salt thereof. The above-mentioned salts include, for example, alkali metal salts, alkaline earth metal salts, alkylamine salts, alkanolamine salts, ammonium salts, and the like. The above-mentioned salts are preferably sodium salts, potassium salts or ammonium salts when used for dyeing the base material for polarizing elements. The azo compound represented by the general formula (1) can be isolated in the form of a free acid by adding mineral acid after the coupling reaction, and the isolated azo compound represented by the general formula (1) can be water or acidified. The inorganic salt can be removed from the isolated azo compound represented by the general formula (1) by washing with water. In this way, the azo compound represented by the general formula (1) in the acid form having a low salt content can be obtained. Next, the azo compound represented by the general formula (1) in the acid form can be neutralized with a desired inorganic or organic base in an aqueous solvent to obtain a solution of the corresponding salt. Or in the case of salting out after the coupling reaction, the azo compound represented by the general formula (1) can be made into a sodium salt using, for example, sodium chloride, or the azo compound represented by the general formula (1) can be made using, for example, potassium chloride. Make potassium salt. In this way, the azo compound represented by the general formula (1) can be turned into a desired salt.

Specific examples of the azo compound represented by the general formula (1) or (2) of the present invention or a salt thereof are given below. In addition, the compound example is shown in the form of a free acid.

(Compound Example 1)

(Compound Example 2)

(Compound Example 3)

(Compound Example 4)

(Compound Example 5)

(Compound Example 6)

(Compound Example 7)

(Compound Example 8)

(Compound Example 9)

(Compound Example 10)

(Compound Example 11)

(Compound Example 12)

(Compound Example 13)

(Compound Example 14)

(Compound Example 15)

(Compound Example 16)

(Compound Example 17)

(Compound Example 18)

[polarizing unit]

The polarizing element of the present invention includes a base material and the aforementioned azo compound of the present invention. The azo compound of the present invention is preferably adsorbed on the aforementioned substrate. The azo compound that can be used as a dye in the polarizing element of the present invention can generally be synthesized by a well-known diazo dye method (for example, page 626 of Non-Patent Document 1) known in the technical field. Manufactured and coupled. The polarizer can be produced by dissolving the azo compound in the solution and impregnating the substrate in the dyeing step.

The polarizing element of the present invention preferably contains, in addition to the azo compound of the present invention, an azo compound or a salt thereof represented by the following general formula (3), which is a dichroic dye.

In this way, a polarizing assembly with higher polarizing performance can be realized. The azo compound represented by the aforementioned general formula (3) or a salt thereof is also preferably adsorbed on the aforementioned substrate.

In the general formula (3), Ar ₁ represents a substituted phenyl group or a substituted naphthyl group, and Rr ₁ to Rr ₆ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkyl group having 1 to 4 carbon atoms. An alkoxy group or an alkoxy group having a sulfonic acid group and having 1 to 4 carbon atoms, Xr ₁ represents an amino group which may have a substituent (excluding phenyl and benzoyl), a phenylamino group which may have a substituent, and an optionally substituted amino group benzoylamino group, optionally substituted phenylazo group, or optionally substituted naphthotriazolyl group, m and n each independently represent 0 or 1.

The azo compound represented by the aforementioned general formula (3) is preferably an azo compound represented by the following general formula (5).

(In the formula, Ar ₁ , Rr ₁ to Rr ₆ , and Xr ₁ have the same meanings as in the general formula (3))

In the aforementioned general formula (3) or (5), Ar ₁ represents a substituted phenyl group or a substituted naphthyl group, and Rr ₁ to Rr ₆ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or An alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms, Xr ₁ represents an amino group that may have a substituent (excluding phenyl and benzoyl), a group that may have a substituent In a phenylamino group, an optionally substituted benzoylamino group, an optionally substituted phenylazo group, or an optionally substituted naphthotriazolyl group, m and n each independently represent 0 or 1.

Rr ₁ to Rr ₆ in the aforementioned general formula (3) or (5) are preferably independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and particularly preferably a hydrogen atom or a methyl group. Rr ₅ and Rr ₆ in the aforementioned general formula (3) or (5), one is an alkoxy group having 1 to 4 carbon atoms, and the other is an alkyl group having 1 to 4 carbon atoms or an alkane having 1 to 4 carbon atoms Oxygen is preferred.

Xr ₁ in the aforementioned general formula (3) or (5) may preferably have one or more selected from the group consisting of methyl, methoxy, sulfonic acid, amino and alkylamino having 1 to 4 carbon atoms. A phenylamino group with two substituents may have a benzoylamino group with one substituent selected from the group consisting of hydroxyl, amino and carboxyethylamino, and may have a hydroxyl group and an alkyl group with 1 to 4 carbon atoms. , phenylazo with 1 to 3 substituents in the group consisting of alkoxy, amino and carboxyethylamino with 1 to 4 carbon atoms, or naphthotri group substituted with 1 or 2 sulfonic acid groups azole group; more preferably a phenylamino group which may have one or two substituents selected from the group consisting of methyl, methoxy, sulfonic acid, amino and alkylamino having 1 to 4 carbon atoms, and may have A benzoylamino group with one substituent selected from the group consisting of hydroxyl, amino and carboxyethylamino groups, or a naphthotriazolyl group substituted with one or two sulfonic acid groups; phenylamino group with one or two substituents in the group consisting of hydroxy group, methoxy group, sulfonic acid group, and amino group, or may have one substituent group selected from the group consisting of hydroxyl group, amino group and carboxyethylamino group benzoylamino.

Ar ₁ in the aforementioned general formula (3) or (5), although it is a substituted phenyl group or a substituted naphthyl group, has an alkyl group selected from a sulfonic acid group, a carboxyl group, and an alkyl group having 1 to 4 carbon atoms. phenyl group with one or two substituents in the group consisting of alkoxy groups with 1 to 4 carbon atoms, or alkoxy groups with 1 to 4 carbon atoms selected from the group consisting of sulfonic acid groups, hydroxyl groups and sulfonic acid groups Naphthyl groups of 2 or 3 substituents in the formed group are preferred.

In Ar ₁ in the aforementioned general formula (3) or (5), the substituent on the phenyl group is a sulfonic acid group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a hydroxyl group. , an alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms, a naphthotriazolyl group substituted with a sulfonic acid group, a nitro group, an amino group, an acetylamino group, or an alkylamino group having 1 to 4 carbon atoms is preferred. In Ar ₁ in the aforementioned general formula (3) or (5), the substituent on the naphthyl group is preferably a sulfonic acid group, a hydroxyl group, or an alkoxy group having a sulfonic acid group and having 1 to 4 carbon atoms. Ar ₁ in the aforementioned general formula (3) or (5) is preferably a phenyl group or a naphthyl group having one or more sulfonic acid groups or carboxyl groups, and in order to improve durability, it is preferable to have two or more sulfonic acid groups The phenyl or naphthyl group of the carboxyl group is more preferred. Ar ₁ in the aforementioned general formula (3) or (5) is more preferably a phenyl group having a sulfonic acid group or a carboxyl group in order to further improve the polarization characteristics and to prepare a neutral-colored polarizing element.

Although m and n in the general formula (3) can be independently 0 or 1, it is preferable that at least one of m and n be 1 to obtain good polarization performance in the polarizing assembly of the present invention, and more Preferably, both m and n are 1. In addition, the substituted amino group is not particularly limited, but may contain, for example, an amino group substituted with an alkyl group or an acyl group having 1 to 4 carbon atoms. Further, although the substituted amide group is not particularly limited, an amide group substituted with an alkyl group having 1 to 4 carbon atoms, a phenyl group which may have a substituent, or a naphthyl group which may have a substituent may be contained.

Although the synthesis method of the azo compound represented by the aforementioned general formula (3) or its salt can be used, for example, Japanese Patent Laid-Open No. 9-302250, Japanese Patent No. 4662853, International Publication No. 2012/108169, International Publication No. 2012/ The method described in No. 108173 etc. is produced, but it is not limited to these methods.

Although the azo compound represented by the aforementioned general formula (3) or its salt can be exemplified by C.I. Direct Red 81, C.I. Direct Red 117, C.I. Direct Red 127, azo compounds described in International Publication No. 2005/075572 (for example, International Publication No. 2005/075572) The azo compound described in Example 1 of Publication No. 2005/075572), the dye described in Japanese Patent No. 4662853, the dye described in International Publication No. 2013/008735, described in Japanese Patent Publication No. 2-61988 azo compounds, azo compounds described in Japanese Patent Laid-Open No. 2013-57909, azo compounds described in International Publication No. 2012/108169 (for example, formulas (8), (9) of International Publication No. 2012/108169 ), (10), (17), azo compounds represented by (21)), etc., but not limited to these.

The azo compound represented by the aforementioned general formula (3) or a salt thereof can be contained in the polarizing element in the form of the free acid represented by the aforementioned general formula (3), and can also be the azo compound represented by the aforementioned general formula (3) The salt form is contained in the polarizer. The above-mentioned salts may be alkali metal salts such as lithium salts, sodium salts, and potassium salts, or organic salts such as ammonium salts or alkylamine salts. Of the above salts, lithium salts or sodium salts are preferred, and sodium salts are more preferred.

Next, specific examples of the azo compound represented by the general formula (3) or a salt thereof that can be used in the polarizing element of the present invention are given below. In addition, in the following compound examples, although substituents, such as a sulfonic acid group, a carboxyl group, and a hydroxyl group, are shown in the form of a free acid, these substituents may be in the form of a salt. (Compound Example 19)

(Compound Example 20)

(Compound Example 21)

(Compound Example 22)

(Compound Example 23)

(Compound Example 24)

(Compound Example 25)

(Compound Example 26)

(Compound Example 27)

(Compound Example 28)

(Compound Example 29)

(Compound Example 30)

(Compound Example 31)

(Compound Example 32)

(Compound Example 33)

(Compound Example 34)

(Compound Example 35)

(化合物例36)

(Compound Example 36)

(Compound Example 37)

(Compound Example 38)

(Compound Example 39)

(Compound Example 40)

(Compound Example 41)

(Compound Example 42)

(Compound Example 43)

(Compound Example 44)

(Compound Example 45)

(Compound Example 46)

(Compound Example 47)

(Compound Example 48)

(Compound Example 49)

(Compound Example 50)

(Compound Example 51)

(Compound Example 52)

(Compound Example 53)

(Compound Example 54)

(Compound Example 55)

(Compound Example 56)

(Compound Example 57)

(Compound Example 58)

(Compound Example 59)

(Compound Example 60)

(Compound Example 61)

(Compound Example 62)

(Compound Example 63)

(Compound Example 64)

(Compound Example 65)

(Compound Example 66)

(Compound Example 67)

(Compound Example 68)

(Compound Example 69)

(Compound Example 70)

(Compound Example 71)

(Compound Example 72)

(Compound Example 73)

(Compound Example 74)

(Compound Example 75)

(Compound Example 76)

(Compound Example 77)

(Compound Example 78)

(Compound Example 79)

(Compound Example 80)

(Compound Example 81)

(Compound Example 82)

(Compound Example 83)

(Compound Example 84)

(Compound Example 85)

(Compound Example 86)

(Compound Example 87)

(Compound Example 88)

(Compound Example 89)

(Compound Example 90)

(Compound Example 91)

(Compound Example 92)

(Compound Example 93)

(Compound Example 94)

(Compound Example 95)

(Compound Example 96)

(Compound Example 97)

(Compound Example 98)

(Compound Example 99)

(Compound Example 100)

(Compound Example 101)

(Compound Example 102)

(Compound Example 103)

(Compound Example 104)

(Compound Example 105)

(Compound Example 106)

(Compound Example 107)

In the polarizing element of the present invention, with respect to 100 parts by weight of the azo compound represented by the general formula (1) or the salt thereof, the content of the azo compound represented by the general formula (3) or the salt thereof is 1 A range of to 200 parts by weight is preferable, and a range of 50 to 100 parts by weight is more preferable.

The polarizing element of the present invention preferably contains an azo compound represented by the following general formula (4) or a salt thereof in addition to the azo compound represented by the aforementioned general formula (1) of the present invention or a salt thereof,

Furthermore, it is more preferable to further contain the azo compound represented by the aforementioned general formula (3) or a salt thereof and the azo compound represented by the aforementioned general formula (4) or a salt thereof. Thereby, a polarizing element having a higher degree of polarization can be realized. The azo compound represented by the aforementioned general formula (4) or a salt thereof is also preferably adsorbed on the aforementioned substrate.

In the aforementioned general formula (4), Ay ₁ represents a sulfonic acid group, a carboxyl group, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and Ry ₁ to Ry ₄ each independently represent a hydrogen atom, In a sulfonic acid group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, p represents an integer of 1 to 3. Ay ₁ in the aforementioned general formula (4) is preferably a carboxyl group or a sulfonic acid group.

Although the synthesis method of the azo compound represented by the aforementioned general formula (4) or its salt can be, for example, the synthesis method described in Non-Patent Document 1 or the synthesis method described in International Publication No. 2007/138980, it is not limited to these methods.

As the azo compound represented by the aforementioned general formula (4) or a salt thereof, for example, C.I. Direct Yellow 12, C.I. Direct Yellow 72, C.I. Direct Orange 39 (CAS number: 1325-54-8), International Publication No. 2007/138980 can be used. The azo compound described in No. (for example, the azo compound of Compound Example 111 described in Example 1 of International Publication No. 2007/138980) is not limited to these compounds.

The azo compound represented by the aforementioned general formula (4) or a salt thereof can be contained in the polarizer in the form of the free acid represented by the aforementioned general formula (4), and can also be the azo compound represented by the aforementioned general formula (4) The salt form is contained in the polarizer. The above-mentioned salts may be alkali metal salts such as lithium salts, sodium salts, and potassium salts, or organic salts such as ammonium salts or alkylamine salts. Of the above salts, lithium salts or sodium salts are preferred, and sodium salts are more preferred.

Next, specific examples of the azo compound represented by the general formula (4) or a salt thereof that can be used in the polarizing element of the present invention are given below. In addition, in the following compound examples, although the sulfonic acid group and the carboxyl group are shown in the form of a free acid, the sulfonic acid group and the carboxyl group may be in the form of a salt.

(Compound Example 108)

(Compound Example 109)

(Compound Example 110)

(Compound Example 111)

In the polarizing element of the present invention, with respect to 100 parts by weight of the azo compound represented by the general formula (1) or the salt thereof of the present invention, the content of the azo compound represented by the general formula (4) or the salt thereof is 1 A range of to 200 parts by weight is preferable, and a range of 50 to 100 parts by weight is more preferable.

In the polarizing element of the present invention, one or more organic dyes other than the azo compounds represented by the general formulae (1), (3) and (4) or salts thereof may be used in combination with color adjustment or the like (for example, non-patent literature). 2, the azo compound, etc.) and the azo compound represented by the general formula (1) of the present invention or a salt thereof. The other organic dye used in combination is not particularly limited, but it is preferable to dye a hydrophilic polymer and belong to a wavelength region different from the absorption wavelength region of the azo compound represented by the general formula (1) of the present invention or a salt thereof. Dyes with absorbing properties and high dichroism. Other organic dyes include, for example, the azo compounds described in Non-Patent Document 2 (for example, C.I. Direct Yellow 28), or C.I. Direct Red 2, C.I. Direct Red 31, C.I. Direct Red 79, C.I. Direct Red 247, and C.I. Direct Red Green 80, C.I. Direct Green 59, C.I. Direct Blue 202, C.I. Direct Violet 9, etc. These azo compounds can be used in the form of free acid or in the form of salts such as alkali metal salts (eg, sodium salts, potassium salts, lithium salts), ammonium salts, and amine salts. When other organic dyes are used in combination as necessary, according to which of the target polarizers belong to more neutral color polarizers, polarizers with characteristic colors, color polarizers for liquid crystal projectors and other color polarizers different types of other organic dyes. The compounding amount of other organic dyes (in the case of two or more types, the total compounding amount of these organic dyes) is not particularly limited, but generally, the amount is relative to the azo compound represented by the general formula (1) of the present invention or a salt thereof. The total amount of the azo compound represented by the aforementioned general formula (3) or its salt, and the azo compound represented by the aforementioned general formula (4) or its salt is 100 parts by weight, preferably in the range of 0.1 to 10 parts by weight.

The aforementioned substrate is preferably a hydrophilic polymer. Although the aforementioned hydrophilic polymer is not particularly limited, for example, polyvinyl alcohol or derivatives thereof, amylose-based resins, starch-based resins, cellulose-based resins, polyacrylate-based resins, etc. may be mentioned. . The base material containing the azo compound of the present invention is most preferably polyvinyl alcohol or its derivative (hereinafter, referred to as "polyvinyl alcohol-based resin") in terms of dyeability, crosslinkability, and the like. The polarizing element of the present invention can be produced by making a substrate into a film shape, adsorbing the azo compound and other formulations of the present invention on the film-like substrate, and applying an orientation treatment such as stretching.

The production method of the polyvinyl alcohol-based resin is not particularly limited, and a known production method can be employed. The manufacturing method of a polyvinyl alcohol-type resin can be obtained by saponifying, for example, a polyvinyl acetate-type resin (homopolymer or copolymer of vinyl acetate). As the polyvinyl acetate-based resin, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, vinyl acetate and copolymers of other monomers that can be copolymerized with vinyl acetate, and the like are exemplified. Examples of other monomers that can be copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids. The polyvinyl alcohol or its derivatives can be further modified, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes.

The degree of saponification of the polyvinyl alcohol-based resin is usually preferably 85 mol% or more, more preferably 95 mol% or more, still more preferably 99 mol% or more, and particularly preferably 99.5 mol% or more. If the degree of saponification is less than the above-mentioned lower limit, the polyvinyl alcohol-based resin may be easily eluted, resulting in in-plane unevenness in optical properties, lowering of dyeability in the dyeing step, cutting in the stretching step, and a concern that the productivity will be significantly lowered. , so not good.

In order to improve the optical properties of the polarizing element of the present invention, the degree of polymerization of the polyvinyl alcohol-based resin is preferably 1,000 to 10,000, more preferably 2,000 to 10,000, still more preferably 3,500 to 10,000, and especially 5,000 to 10,000 Preferred. When the degree of polymerization exceeds 10,000, the polyvinyl alcohol-based resin becomes hard, film-forming properties or elongation are lowered, and productivity is lowered, so from an industrial point of view, the degree of polymerization is preferably 10,000 or less. The degree of polymerization of the polyvinyl alcohol-based resin, which means the viscosity-average degree of polymerization, can be obtained by a well-known method in the technical field.

Hereinafter, a specific manufacturing method of a polarizing element will be described by taking a case where the substrate is a film formed of a polyvinyl alcohol-based resin as an example.

First, by forming the polyvinyl alcohol-based resin into a film, a raw film formed of the polyvinyl alcohol-based resin is obtained. The film-forming method of polyvinyl alcohol-based resin, although in addition to the method of melting and extruding the water-containing polyvinyl alcohol-based resin, casting film-forming method, wet film-forming method (film-forming by discharging into a poor solvent) can also be used. method), gel film-forming method (a method in which an aqueous solution of polyvinyl alcohol-based resin is temporarily cooled and gelled, and then the solvent is extracted and removed), casting film-forming method (where an aqueous solution of polyvinyl alcohol-based resin is made to flow on a substrate) , drying method) and methods obtained by combining these methods, etc., but are not limited to these methods.

When a solvent is used for film formation, the solvent is not particularly limited, and examples thereof include dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene glycol, glycerin, and propylene glycol. , Diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylolpropane, ethylenediamine, diethylenetriamine, water, etc. The solvent may be used alone or in combination of two or more. The amount of the solvent used in film formation is preferably 70 to 95% by weight relative to the entire film formation stock solution (mixed solution containing polyvinyl alcohol-based resin and solvent used in film formation), but is not limited. However, if the amount of the solvent is less than 70% by weight, the viscosity of the membrane-forming stock solution becomes high, filtration and defoaming during preparation become difficult, and it is difficult to obtain a native membrane without foreign matter or defects. In addition, if the amount of the solvent exceeds 95% by weight, the viscosity of the film-forming stock solution becomes too low, and it is difficult to control the desired thickness, the influence of surface fluctuations due to the wind during drying increases, and the drying time becomes longer and the production Decreased sex.

Plasticizers can also be used when making virgin films. The aforementioned plasticizers include, but are not limited to, glycerin, diglycerol, ethylene glycol, propylene glycol, and low-molecular-weight polyethylene glycol. Although the usage-amount of the said plasticizer is not specifically limited, Usually, it is suitable in the range of 5-15 weight part with respect to 100 weight part of polyvinyl alcohol-type resin.

The drying method of the raw film after film formation includes, for example, drying by hot air, contact drying by a hot roll, drying by an infrared heater, and the like, but is not limited. One of these drying methods may be used alone, or two or more of them may be used in combination. Although the drying temperature is not particularly limited, it is preferably in the range of 50 to 70°C.

When the degree of swelling of the dried virgin film is to be controlled within a predetermined range described later, it is preferable to perform heat treatment. The heat treatment method of the raw film after film formation includes, for example, a method by hot air, a method of contacting the raw film with a heated roll, and the like, but is not particularly limited as long as it is a method that can be processed by heat. One of these methods may be used alone, or two or more of them may be used in combination. Although the heat treatment temperature is not particularly limited, it is preferably in the range of 110 to 140°C. The time for the heat treatment is usually about 1 to 10 minutes, but is not particularly limited.

The thickness of the primary film thus obtained is preferably 20 to 100 μm, more preferably 20 to 80 μm, and still more preferably 20 to 60 μm. When the thickness is less than 20 μm, cracking of the film is likely to occur. If the thickness exceeds 100 μm, the stress on the film during stretching increases, and the mechanical load during the stretching step increases, and a large-scale device capable of withstanding the load is required.

The following swelling process was implemented about the raw film formed from the polyvinyl alcohol-type resin obtained by the above.

The said swelling process is performed by immersing the virgin film formed of the polyvinyl alcohol-based resin in a solution of 20 to 50° C. for 30 seconds to 10 minutes. The aforementioned solution is preferably an aqueous solution. Since the swelling of the film also occurs during the dyeing process of the azo compound, the swelling step may be omitted when it is desired to shorten the time for producing the polarizer.

The degree of swelling F of the native film is preferably 180 to 260%, more preferably 200 to 240%, and still more preferably 210 to 230%. When the degree of swelling F is less than 200%, the elongation at the time of stretching becomes small, and the possibility of cracking at a low magnification becomes high. If it is less than 180%, the elongation at the time of elongation is remarkably lowered, the possibility of cracking becomes high, and it becomes difficult to carry out sufficient elongation. On the other hand, when the degree of swelling F exceeds 240%, the swelling becomes excessive, and wrinkles or slack occur, which gradually causes cutting at the time of stretching. When the degree of swelling F exceeds 260%, it is unfavorable because it obviously causes wrinkles or sagging. When it is desired to control the degree of swelling F, for example, an appropriate degree of swelling F can be achieved by the temperature and time when heat-treating the original film after film formation.

The degree of swelling F of the virgin membrane can be measured by a well-known method in this technical field, for example, by the following method. First, the native membrane was cut into 5 cm×5 cm, and immersed in 1 L of distilled water at 30° C. for 4 hours. The immersed membrane was taken out from distilled water and sandwiched between two pieces of filter paper to absorb water droplets on the membrane surface, and then the weight [β(g)] of the membrane immersed in water was measured. Then, the film immersed and absorbed the water droplets was dried using a dryer at 105°C for 20 hours, cooled in a desiccator for 30 minutes, and then the weight [γ(g)] of the dried film was measured. Then, the degree of swelling F of the native membrane was calculated by the following formula (v).

Degree of swelling F=100×β/γ(%)…(v)

After the swelling step, a dyeing step is performed. In the dyeing step, the azo compound of the present invention (an azo compound represented by the general formula (1) or a salt thereof) may be mixed with other azo compounds (an azo compound represented by the general formula (3) or a salt thereof) as needed , the azo compound represented by the general formula (4) or its salt, etc.) and adsorbed together on the polyvinyl alcohol-based resin film.

The above-mentioned dyeing step is not particularly limited as long as it is a method of adsorbing the azo compound to the polyvinyl alcohol-based resin film. For example, it can be performed by immersing the polyvinyl alcohol-based resin film in a solution containing the azo compound. The solution temperature in this dyeing step is preferably 5 to 60°C, more preferably 20 to 50°C, and particularly preferably 35 to 50°C. The time of immersion in the solution can be appropriately adjusted, but it is preferably adjusted to 30 seconds to 20 minutes, and more preferably 1 to 10 minutes. The dyeing method is preferably a method of immersing the polyvinyl alcohol-based resin film in the above-mentioned solution, but may be a method of applying the solution to the polyvinyl alcohol-based resin film.

A solution containing an azo compound belonging to a dichroic dye may contain sodium carbonate, sodium bicarbonate, sodium chloride, sodium sulfate, anhydrous sodium sulfate, sodium tripolyphosphate, etc. as dyeing auxiliaries. The content of these dyeing auxiliaries can be adjusted to any concentration in accordance with the time and temperature of dyeing due to the dyeability of the azo compound, but is preferably 0 to 5% by weight, and more preferably 0.1 to 2% by weight.

After the dyeing step, before proceeding to the next step, a washing step (hereinafter, referred to as "washing step 1") may be performed. The cleaning step 1 is a step of cleaning the dye solvent adhering to the surface of the polyvinyl alcohol-based resin film in the dyeing step with a cleaning solution. By performing the washing step 1, it is possible to suppress the migration of the dye to the liquid to be processed next. In the cleaning step 1, water is usually used as the cleaning liquid. The cleaning method is preferably a method of immersing in a cleaning solution, but a method of applying the cleaning solution to the polyvinyl alcohol-based resin film may also be used. Although the washing time is not particularly limited, it is preferably 1 to 300 seconds, and more preferably 1 to 60 seconds. The temperature of the cleaning solution in the cleaning step 1 must be a temperature at which the hydrophilic polymer is not dissolved, and is usually 5 to 40°C.

After the dyeing step or the washing step 1, a step of adding a crosslinking agent and/or a water-resistant agent to the polyvinyl alcohol-based resin film may be performed. As the aforementioned crosslinking agent, for example, boron compounds such as boric acid, borax or ammonium borate, polyaldehydes such as glyoxal and glutaraldehyde, polyisocyanates such as biuret type, isocyanurate type or block type can be used. Compounds, titanium-based compounds such as titanium oxysulfate, etc., and ethylene glycol glycidyl ether, polyamide epichlorohydrin, etc. can also be used, but boric acid is preferable. The aforementioned water-resistant agents include peroxysuccinic acid, ammonium persulfate, calcium perchlorate, benzoin ethyl ether, ethylene glycol diglycidyl ether, glycerol diglycidyl ether, ammonium chloride, and magnesium chloride. Wait.

The step of making the polyvinyl alcohol-based resin film contain the crosslinking agent and/or the water resistance agent is performed using at least one of the crosslinking agents and/or the water resistance agent shown above. The aforementioned crosslinking agent and/or water-resistance agent are usually used in the state of a solution dissolved in a solvent. Although the aforementioned solvent is preferably water, it is not limited. In the step of containing the aforementioned cross-linking agent and/or water-resistance agent, the concentration of the cross-linking agent and/or water-resistance agent in the solvent is preferably 0.1 to 6.0% by weight relative to the solvent when boric acid is used as an example. , and more preferably 1.0 to 4.0% by weight. The temperature of the solvent in this step is preferably 5 to 70°C, and more preferably 5 to 50°C. The method of making the polyvinyl alcohol-based resin film contain a cross-linking agent and/or a water-resistant agent is preferably a method of immersing the polyvinyl-alcohol-based resin film in a solution of the cross-linking agent and/or the water-resistant agent, but may also be It is a method of applying or coating the solution to a polyvinyl alcohol-based resin film. The treatment time in this step is preferably 30 seconds to 6 minutes, and more preferably 1 to 5 minutes. However, it is not necessary to include a cross-linking agent and/or a water-resistance agent in the polyvinyl alcohol-based resin film. Therefore, when the manufacturing time of the polarizing element is to be shortened, and when the cross-linking treatment or water-resistance treatment is not required, this treatment may be omitted. step.

The stretching step is performed after the dyeing step, after the washing step 1, or after the step containing a crosslinking agent and/or a water-resistance agent. The stretching step is a step of uniaxially stretching the polyvinyl alcohol-based resin film. The stretching method may be either a wet stretching method or a dry stretching method. Although the stretching ratio can achieve the present invention as long as 3 times or more, it is preferably 5 times to 7 times.

In the dry stretching method, when the stretching heating medium is an air medium, the temperature of the air medium during stretching is preferably from normal temperature to 180°C. In addition, it is preferable to carry out the stretching treatment in an ambient air having a humidity of 20 to 95% RH. The stretching method includes, for example, the inter-roll zone stretching method, the roll heating stretching method, the pressure stretching method, the infrared heating stretching method, and the like, but is not limited to this stretching method. The stretching step may be performed by one-stage stretching, or may be performed by two or more multi-stage stretching.

In the wet stretching method, the polyvinyl alcohol-based resin film is stretched in water, a water-soluble organic solvent, or a mixed solution of these. It is preferable to carry out the stretching treatment while immersing the polyvinyl alcohol-based resin film in a solution containing the above-mentioned crosslinking agent and/or water resistance agent. As the aforementioned crosslinking agent, for example, boron compounds such as boric acid, borax, or ammonium borate, polyaldehydes such as glyoxal and glutaraldehyde, and polyisocyanates such as biuret-type, isocyanurate-type, or block-type can be used. Compounds, titanium-based compounds such as titanium oxysulfate, and the like, and others such as ethylene glycol glycidyl ether, polyamide epichlorohydrin, and the like can also be used. The aforementioned water-resistant agents include peroxysuccinic acid, ammonium persulfate, calcium perchlorate, benzoin ethyl ether, ethylene glycol diglycidyl ether, glycerol diglycidyl ether, ammonium chloride, and magnesium chloride. Wait.

The step of incorporating a crosslinking agent and/or a water resistance agent in the polyvinyl alcohol-based resin film is performed using at least one of the crosslinking agents and/or water resistance agents shown above. The aforementioned crosslinking agent and/or water-resistance agent are usually used in the state of a solution dissolved in a solvent. Although the aforementioned solvent is preferably water, it is not limited.

The stretching of the polyvinyl alcohol-based resin film is performed in a solution containing at least one or more of the above-described crosslinking agents and/or water-resistance agents. The aforementioned crosslinking agent is preferably boric acid. The concentration of the crosslinking agent and/or the water-resistance agent in the aforementioned extending step is preferably, for example, 0.5 to 15 wt %, and more preferably 2.0 to 8.0 wt %. The stretching ratio is preferably 2 to 8 times, and more preferably 5 to 7 times. The extension temperature is preferably 40 to 60°C, and more preferably 45 to 58°C. The extension time is usually 30 seconds to 20 minutes, but more preferably 2 to 5 minutes. The wet stretching step may be performed by one-stage stretching, or may be performed by two or more multi-stage stretching.

After the stretching step, the crosslinking agent and/or water-resisting agent may be precipitated on the membrane surface, or foreign matter may be adsorbed, so a washing step (hereinafter, referred to as "washing step 2") for washing the membrane surface may be performed. . The washing time is preferably 1 second to 5 minutes. The cleaning method is preferably a method of immersing in a cleaning solution, but a method of applying or coating the cleaning solution to a polyvinyl alcohol-based resin film may also be used. The cleaning treatment may be performed in one stage, or in two or more stages of multi-stage treatment. 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.

Examples of the solvent used in the treatment steps up to this point include water; dimethyl sulfoxide; N-methylpyrrolidone; methanol, ethanol, propanol, isopropanol, glycerol, ethylene glycol, propylene glycol, and diethylene glycol. Alcohols, such as alcohols, triethylene glycol, tetraethylene glycol, and trimethylolpropane; solvents such as amines such as ethylenediamine and diethylenetriamine, but are not limited to these solvents. In addition, a mixture of one or more of these solvents may be used. The most preferred solvent is water.

After the stretching step or the washing step 2, the drying step of the polyvinyl alcohol-based resin film is performed. The drying treatment can be carried out by natural drying, but in order to further improve the drying efficiency, the moisture on the surface can be removed by compression through a roll, an air knife, a suction roll, etc. Air drying is performed together with the removal of moisture, or air drying is performed in place of such water removal. The temperature of the drying treatment is preferably 20 to 100°C, and more preferably 60 to 100°C. Although the drying time can be set in the range of 30 seconds to 20 minutes, it is preferably 5 to 10 minutes.

In the present invention, when the polarization performance is to be further improved, iodine may be adsorbed on the substrate by using, for example, an iodine-containing dyeing solution within the range in which the desired durability can be maintained, and the iodine may be contained in the polarizer. middle. The aforementioned dyeing solution contains iodine and iodide. As the aforementioned iodide, for example, potassium iodide, ammonium iodide, cobalt iodide, zinc iodide and the like can be used, but it is not limited to the iodide shown here. The iodine concentration is preferably 0.0001 to 0.5% by weight, and more preferably 0.001 to 0.4% by weight. The iodide concentration is preferably 0.0001 to 8% by weight. As the processing step at this time, for example, any one of the dyeing step, the washing step 1, the stretching step, and the washing step 2 can be used, or a plurality of these steps can be used. The treatment temperature is preferably 5 to 60°C, more preferably 5 to 50°C, and particularly preferably 10 to 40°C. Although the treatment time can be adjusted appropriately, it is preferably adjusted to 30 seconds to 20 minutes, and more preferably 1 to 5 minutes.

As described above, the polarizing element of the present invention has excellent polarization performance because the azo compound represented by the general formula (1) is used as the azo compound in the polarizing element including the base material and the azo compound.

[polarizing plate]

The polarizing plate of the present invention includes the polarizing element of the present invention and a transparent protective layer provided on at least one side of the polarizing element.

The said transparent protective layer can be provided as a coating layer which consists of a transparent polymer, or a laminated|stacked layer of a transparent film. The transparent polymer or transparent film forming the transparent protective layer is preferably a transparent polymer or transparent film with high mechanical strength and good thermal stability. The transparent polymer or transparent film used for the transparent protective layer includes, for example, cellulose acetate resin such as triacetyl cellulose or diacetyl cellulose, or its film, acrylic resin or its film, and polyvinyl chloride resin. or its film, nylon resin or its film, polyester resin or its film, polyarylate resin or its film, cyclic polyolefin resin or its film containing cyclic olefin such as norbornene as a monomer, polyethylene, Polypropylene, polyolefins having a ring system or norbornene skeleton or copolymers thereof, polymers (or resins) whose main chain or side chain is imide and/or amide, or films thereof, etc. In addition, a resin having liquid crystallinity or a film thereof may be provided as the transparent protective layer. The thickness of the aforementioned protective film is, for example, about 0.5 to 200 μm. One layer of resin or film can be provided on one side of the polarizer, two or more layers of the same or different resins or films can be provided on one side of the polarizer, and one or more layers of the same type can be provided on both sides of the polarizer. Or different kinds of resins or films.

Adhesives can be used to bond the aforementioned transparent protective layer to the polarizing element. Although the aforementioned adhesive is not particularly limited, a polyvinyl alcohol adhesive is preferred. The aforementioned polyvinyl alcohol adhesives include, for example, GOHSENOL (registered trademark) NH-26 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), EXCEVAL (registered trademark) RS-2117 (manufactured by KURARAY Co., Ltd.), etc., but not limited to to these. In the aforementioned adhesive, a cross-linking agent and/or a water-resistant agent may be added. In the aforementioned polyvinyl alcohol adhesive, maleic anhydride-isobutylene copolymer may be mixed, and at this time, a cross-linking agent may be further mixed as required. Examples of the maleic anhydride-isobutylene copolymer include ISOBAM (registered trademark) #18 (manufactured by KURARAY Co., Ltd.), ISOBAM (registered trademark) #04 (manufactured by KURARAY Co., Ltd.), ammonia-modified ISOBAM (registered trademark) #104 (manufactured by KURARAY Co., Ltd.), ammonia-modified ISOBAM (registered trademark) #110 (manufactured by KURARAY Co., Ltd.), imidized ISOBAM (registered trademark) #304 (manufactured by KURARAY Co., Ltd.) , Imidated ISOBAM (registered trademark) #310 (manufactured by KURARAY Co., Ltd.), and the like. A water-soluble polyvalent epoxy compound can be used as the crosslinking agent to be mixed in the maleic anhydride-isobutylene copolymer as needed. As said water-soluble polyvalent epoxy compound, DENACOL EX-521 (made by Nagase ChemteX Co., Ltd.), TETRAD (registered trademark)-C (made by Mitsubishi Gas Chemical Co., Ltd.), etc. are mentioned, for example. Moreover, well-known adhesives other than polyvinyl alcohol adhesives, such as a urethane type adhesive agent, an acrylic type adhesive agent, and an epoxy type adhesive agent, can also be used for the said adhesive agent. In addition, additives such as zinc compounds, chlorides, and iodides may be contained in the adhesive at a concentration of about 0.1 to 10% by weight for the purpose of improving the adhesive strength of the adhesive or improving the water resistance. Additives are not limited. After attaching the transparent protective layer with an adhesive on at least one side of the polarizing element, drying or heat treatment at a moderate temperature can obtain a polarizing plate.

The aforementioned polarizing plate can also be attached to display devices such as liquid crystal display devices, organic electroluminescent display devices, etc., depending on the situation, or can be provided on the surface of the transparent protective layer that will become a non-exposed surface after lamination. Various functional layers, layers or films with improved viewing angle and/or improved contrast. When attaching a polarizing plate to these layers or films, or a display device, it is preferable to use an adhesive.

The polarizing plate may be a polarizing plate provided with various well-known functional layers such as an antireflection layer, an antiglare layer, and a hard coat layer on the other surface, that is, the exposed surface, of the transparent protective layer. When producing these various functional layers, although a coating method is preferable, a method of bonding a film having the function through an adhesive or an adhesive can also be used. In addition, the above-mentioned functional layer can be used as a layer or film for controlling the retardation.

As described above, the polarizing plate of the present invention is represented by the aforementioned general formula (1) in a polarizing plate including a polarizing element containing a base material and an azo compound, and a transparent protective layer provided on at least one side of the polarizing element. As the aforementioned azo compound, the azo compound has excellent polarizing properties.

The polarizing assembly and polarizing plate of the present invention can be used in display devices such as liquid crystal display devices. A display device using the polarizing assembly or polarizing plate of the present invention can be a display device with high contrast ratio.

In addition, the polarizing assembly and polarizing plate of the present invention are respectively provided with protective layers or functional layers and supports as required, and are used in liquid crystal projectors, electronic calculators, clocks, notebook computers, word processors, liquid crystal televisions, polarized light Lenses, polarized glasses, car navigators, organic electroluminescent displays, indoor and outdoor measuring instruments and indicators, etc.

In the application method of the polarizing plate of the present invention, the polarizing plate of the present invention can be attached to a support and used as a polarizing plate with a support. The aforementioned support body preferably has a flat portion because the polarizing plate is attached. Moreover, since the said support body belongs to an optical use, it is preferable to use a glass molded article. As said glass molded article, a glass plate, a lens, a prism (for example, a triangular prism, a cubic prism, etc.) etc. are mentioned, for example. A polarizing plate is attached to the lens, which can be used as a condenser lens with a polarizing plate in an LCD video camera. In addition, a polarizing plate is attached to the prism, and it can be used as a polarizing beam splitter with a polarizing plate or a dichroic prism with a polarizing plate in a liquid crystal projector. Alternatively, a polarizing plate may be attached to the liquid crystal cell. The material of the glass molded article includes, for example, inorganic glass such as soda glass, borosilicate glass, crystal, and sapphire, and organic plastic such as acrylic resin and polycarbonate, but inorganic glass is preferred. . The thickness or size of the aforementioned glass plate may be a desired size. In addition, in the polarizing plate with a supporting body provided with a supporting body formed of glass, when it is desired to further improve the light transmittance of a single plate, an anti-reflection layer (AR layer) is provided on one or both surfaces of the glass surface and the polarizing plate surface. Preferred. On the surface of such a support, for example, the surface of the plane part of the support, a transparent adhesive (adhesive) agent is coated, and then the polarizing plate of the present invention is attached to the coated surface. In addition, a transparent adhesive (adhesive) agent can also be coated on the polarizing plate, and then the support body can be attached to the coated surface. The adhesive (adhesive) used at this time is preferably, for example, an acrylate type. In addition, when combining this polarizing plate with a retardation plate and using it as an elliptical polarizing plate, although the retardation plate side of the elliptical polarizing plate is usually attached to the support, the polarizing plate side of the elliptical polarizing plate may also be attached. on the support body.

[display screen]

The display device of the present invention includes the polarizing assembly of the present invention or the polarizing plate of the present invention. In addition, the display device of the present invention may be a reflective type, transmissive type, or both transmission/reflection type including, for example, a liquid crystal cell and the polarizing element of the present invention or the polarizing plate of the present invention arranged on one side or both sides of the liquid crystal cell. and other liquid crystal display devices. The above-mentioned liquid crystal cell is optional, for example, an active matrix driving type liquid crystal cell represented by a thin film transistor type, a simple matrix driving type liquid crystal cell represented by a twisted nematic type or a super twisted nematic type, and the like can be used. liquid crystal cell.

In addition, in the display device of the present invention, one or more other suitable optical members such as prism array sheets, lens array sheets, light diffusing plates, and backlights may be arranged at suitable positions. When the polarizing assembly of the present invention, the polarizing plate of the present invention, and other optical members are provided, these may be the same on both sides, or may be different on both sides.

The display device of the present invention can also be made into a display device having an adhesive layer on one side or both sides of the polarizing assembly of the present invention or the polarizing plate of the present invention for adhering to other components such as liquid crystal cells. For the formation of the adhesive layer, suitable adhesive substances or adhesives can be used, and there is no particular limitation. Examples of the constituent material of the adhesive layer include materials in which suitable polymers such as acrylic resins, silicone resins, polyesters, polyurethanes, polyamides, polyethers, fluororesins, and rubbers are used as matrix polymers.

The display device of the present invention can be used for twisted nematic (TN), super twisted nematic (STN), thin film transistor (TFT), vertical alignment (VA), in-plane switching (IPS) and other liquid crystal displays The device as a whole, and other display devices.

[Example]

Hereinafter, although the present invention will be described in more detail by way of examples, the present invention is not limited to the scope of these examples. In addition, the measurement of the transmittance|permeability, polarization degree, and contrast value of the polarizing element and the polarizing plate obtained in the Example and the comparative example was performed as follows.

[Measurement method of transmittance and polarization degree of polarizing element]

Let the transmittance at each wavelength of one polarizer be the single transmittance Ts, and the transmittance at each wavelength when two polarizers are superimposed so that the absorption axis directions of these polarizers are the same as the parallel The vertical transmittance Tp and the transmittance at each wavelength when two polarizers are superimposed so that the absorption axes of these polarizers are perpendicular are referred to as the vertical transmittance Tc. The respective transmittances Ts, Tp, and Tc were measured at each wavelength at 5 nm intervals using a spectrophotometer (“U-4100” manufactured by Hitachi High-Technologies Co., Ltd.).

The degree of polarization ρ (%) of the polarizer is calculated by the following formula from the transmittance Tp at the parallel position and the transmittance Tc at the perpendicular position.

ρ={(Tp-Tc)/(Tp+Tc)} ^1/2 ×100

[Measurement method of transmittance, polarization degree and contrast value of polarizing plate]

When the transmittance obtained by correcting the transmittance at each wavelength of one polarizing plate by visual sensitivity is taken as the single transmittance Ys, and when two polarizing plates are superimposed so that the absorption axis directions of these polarizing plates are the same The transmittance at each wavelength obtained by correcting the visual sensitivity is defined as the parallel-position transmittance Yp, and the transmittance at each wavelength when two polarizers are superimposed so that the absorption axes of these polarizers are perpendicular to each other. The transmittance obtained by the sensitivity correction is referred to as the vertical position transmittance Yc. The visual sensitivity correction is performed according to JIS Z 8722:2009 with a C light source of 2° field of view and a chromaticity function. The respective transmittances Ys, Yp, and Yc were measured at respective wavelengths at 5 nm intervals using a spectrophotometer (“U-4100” manufactured by Hitachi High-Tech Co., Ltd.).

The degree of polarization Py (%) of the polarizing plate is calculated by the following formula (16) from the parallel position transmittance Yp corrected for viewing sensitivity and the vertical position transmittance Yc corrected for viewing sensitivity.

Py={(Yp-Yc)/(Yp+Yc)} ^1/2 ×100…(16)

The contrast value (CR) of the polarizing plate is calculated by the following formula (17) from the parallel position transmittance Yp corrected for viewing sensitivity and the vertical position transmittance Yc corrected for viewing sensitivity.

CR=Yp/Yc…(17)

[Example 1]

<Synthesis of azo compound of compound example 1>

25.3 parts by weight of 4-aminobenzene-1,3-disulfonic acid was added to 500 parts by weight of water, cooled and below 10°C, 31.3 parts by weight of a 35% by weight aqueous hydrochloric acid solution, and then 6.9 parts by weight of sodium nitrite, It was diazotized by stirring at 5 to 10°C for 1 hour. For this, 10.7 parts by weight of 3-methylaniline dissolved in a dilute aqueous hydrochloric acid solution was added as a primary coupling agent (coupling component), and while stirring at 10 to 30° C., sodium carbonate was added to make pH 3, and the coupling was further stirred. After the reaction was completed, 29.7 parts by weight of the monoazoamino compound represented by the following structural formula (18) was obtained by filtration.

The obtained monoazoamino compound of structural formula (18) was added to 400 parts by weight of water, dissolved in sodium hydroxide, 25.0 parts by weight of a 35% by weight aqueous hydrochloric acid solution was added at 10 to 30° C., and then 5.5 parts by weight of sodium nitrite was added. , and stirred at 20 to 30 °C for 1 h to diazotize it. For this, 8.6 parts by weight of 3-methylaniline dissolved in a dilute aqueous hydrochloric acid solution was added as a secondary coupling agent, and while stirring at 20 to 30 °C, sodium carbonate was added to make pH 3, and the coupling reaction was completed by stirring again. , to obtain 31.3 parts by weight of the bisazoamino compound represented by the following structural formula (19).

The bisazoamino compound of the obtained structural formula (19) was added to 250 parts by weight of water, dissolved in sodium hydroxide, 20.0 parts by weight of a 35% by weight aqueous hydrochloric acid solution was added at 20 to 30° C., and then 4.4 parts by weight of sodium nitrite was added. , and stirred at 20 to 30 °C for 1 h to diazotize it. In this regard, 8.8 parts by weight of 2-methoxy-5-methylaniline dissolved in a dilute aqueous hydrochloric acid solution was added as a tertiary coupling agent, and while stirring at 20 to 30° C., sodium carbonate was added to adjust the pH to 3.5. Further stirring was performed to complete the coupling reaction, followed by filtration to obtain 32.6 parts by weight of the trisazoamino compound represented by the following structural formula.

The obtained trisazoamino compound of structural formula (20) was added to 200 parts by weight of water, dissolved in sodium hydroxide, 16.0 parts by weight of a 35% by weight aqueous hydrochloric acid solution was added at 20 to 30° C., and then 3.5 parts by weight of sodium nitrite was added. , stirred at 20 to 30° C. for 1 hour, and then diazotized to obtain the diazonium compound of the trisazoamino compound. In addition, as a 4th coupling agent, 16.1 parts by weight of 6-phenylamino-1-naphthol-3-sulfonic acid was added to 50 parts by weight of water, and dissolved with sodium carbonate as a weak base to obtain a 4th coupling agent The solution.

In the solution of the 4-time coupling agent, the previously obtained diazonium compound of the trisazoamino compound was kept at pH 8 to 10 and injected, stirred, and the coupling reaction was completed. Then, 30.5 parts by weight of monoethanolamine was added to an aqueous solution of 25 parts by weight of copper sulfate, and the reaction was carried out at 95° C. for 10 hours, and the copperization reaction was performed until the unreacted material was not recognized by thin layer chromatography. After the reaction, it was salted out with sodium chloride and filtered to obtain 46.4 parts by weight of the azo compound (copper tetrazo compound) of Compound Example 1 as an example of the azo compound represented by the general formula (1).

<Production of polarizing element>

A polyvinyl alcohol film with a saponification degree of 99 mol% or more as a base material and a film thickness of 40 μm (“VF-PE#4000” manufactured by KURARAY Co., Ltd.; hereinafter referred to as “film”) was immersed in warm water at 35°C For 3 minutes, swelling treatment was performed. On the other hand, by combining 1.0 parts by weight of the azo compound of Compound Example 1 as the azo compound represented by the general formula (1) or its salt, 1.0 part by weight of anhydrous sodium sulfate as a dyeing aid, and 2,000 parts by weight of water The mixture was mixed to prepare an aqueous solution at 40°C. The swelled membrane was immersed in the aqueous solution at 40°C, so that the azo compound was adsorbed on the membrane.

The azo compound-adsorbed film was washed with water, and then subjected to boric acid treatment for 1 minute with an aqueous solution containing 2% by weight of boric acid at 40°C. The boric acid treatment was performed for 5 minutes in a 58° C. aqueous solution containing 3.0 wt % of boric acid while extending the film obtained by the boric acid treatment to 5.0 times. While maintaining the film obtained by the boric acid treatment in a taut state, washing treatment was performed for 20 seconds with water at room temperature. The film obtained by the washing process was immediately subjected to a drying process at 60° C. for 5 minutes to obtain a film-shaped polarizer having a film thickness of 15 μm. The polarizing element containing the azo compound represented by General formula (1) or its salt which is an example of this invention was produced by the above-mentioned method.

[Example 2]

<Synthesis of azo compound of compound example 17>

28.2 parts by weight of (7,8-disulfo-2H-naphtho[1,2-d]triazol-2-yl-)-1-naphthol-3-sulfonic acid except as a 4th coupling agent Except for 16.1 parts by weight of substituted 6-phenylamino-1-naphthol-3-sulfonic acid, a compound represented by the general formula (1) was obtained in the same manner as in the synthesis of the azo compound of Compound Example 1 in Example 1. An azo compound or its salt compound The azo compound (copper tetrazo compound) of Compound Example 17.

<Production of polarizing element>

A polarizing element was produced in the same manner as in Example 1, except that the azo compound of Compound Example 17 was used in place of the azo compound of Compound Example 1.

[Comparative Example 1]

A polarizing element was produced in the same manner as in Example 1, except that the copperized azo compound described in Example 38 of Japanese Patent Laid-Open No. 60-156759 was used instead of the azo compound of Compound Example 1.

[Comparative Example 2]

A polarizing element was produced in the same manner as in Example 1, except that the copperized azo compound described in Example 1 of Japanese Patent Publication No. 64-5623 was used instead of the azo compound of Compound Example 1.

In Table 1, the single transmittance Ts, the parallel position transmittance Tp, the perpendicular position transmittance Tc, and the polarized light at the wavelength with the highest degree of polarization in the polarizing assemblies of Examples 1 and 2 and the polarizing assemblies of Comparative Examples 1 and 2 are shown The measurement result of the degree ρ.

[Table 1]

Ts(%) Tp(%) Tc(%) ρ(%) Example 1 44.05 38.33 0.482 98.75 Example 2 43.91 37.98 0.582 98.48 Comparative Example 1 44.02 37.44 1.315 96.55 Comparative Example 2 43.96 35.78 2.872 92.27

As can be seen from Table 1, the polarizing elements using the copper-coated azo compounds of Examples 1 and 2 of the present invention have the same degree of transmittance as the copper-coated azo compounds known so far. Raised by leaps and bounds.

[Example 3]

First, a polyvinyl alcohol film with a saponification degree of 99 mol% or more as a base material and a film thickness of 40 μm (“VF-PE#4000” manufactured by KURARAY Co., Ltd.; hereinafter referred to as “film”) was immersed at 35° C. for 3 minutes in warm water for swelling treatment. In addition, 2.0 parts by weight of the azo compound of the compound example 1 which is the azo compound represented by the general formula (1) or the salt thereof, and the azo compound of the compound example 20 which is the azo compound represented by the general formula (3) or the salt thereof. 0.5 parts by weight of nitrogen compound (C.I. Direct Red 117), the azo compound of Compound Example 111 which is an azo compound represented by the general formula (4) or a salt thereof (the azo compound described in Example 1 of International Publication No. 2007/138980) Nitrogen compound) 0.5 weight part, 1.0 weight part of sodium tripolyphosphate and 1.0 weight part of anhydrous sodium sulfate as a dyeing assistant, and 2,000 weight part of water, and the aqueous solution of 40 degreeC was prepared. The swelled membrane was immersed in the aqueous solution at 40°C, so that the azo compound was adsorbed on the membrane.

The azo compound-adsorbed film was washed with water, and then subjected to boric acid treatment with a 30°C aqueous solution containing 2% by weight of boric acid for 1 minute. The boric acid treatment was performed for 5 minutes in a 58° C. aqueous solution containing 3.0% by weight of boric acid while extending the film obtained by the boric acid treatment to 5.0 times. While maintaining the film obtained by the boric acid treatment in a taut state, washing treatment was performed for 20 seconds with water at room temperature. The film obtained by the washing process was immediately subjected to a drying process at 60° C. for 5 minutes to obtain a film-shaped polarizer having a film thickness of 15 μm. The azo compound represented by the general formula (1) or its salt, the azo compound represented by the general formula (3) or its salt, and the azo compound represented by the general formula (4) or The polarizing component of its salt.

On both sides of the obtained polarizer, an alkali-treated triacetyl cellulose film with a film thickness of 80 μm (“TD-80U” manufactured by Fuji Photo Film Co., Ltd.; hereinafter abbreviated as “TAC”) was coated with a polyvinyl alcohol adhesive. Adhesion, whereby the composition of TAC/adhesion layer/polarizer/adhesion layer/TAC is laminated. Thereby, a polarizing plate is obtained. The obtained polarizing plate was used as a measurement sample.

[Example 4]

As the azo compound represented by the general formula (1) or its salt, 3.0 parts by weight of the azo compound of the compound example 17 used in Example 2 was used in place of 2.0 parts by weight of the azo compound of the compound example 1. The same operation was used to prepare a film containing the azo compound represented by the general formula (1) or its salt, the azo compound represented by the general formula (3) or its salt, and the azo compound represented by the general formula (4) or its salt. At the same time, a polarizing plate was produced, and the produced polarizing plate was used as a measurement sample.

[Example 5]

In addition to the azo compound represented by the general formula (3) or a salt thereof, 1.0 parts by weight of the sodium salt of the azo compound of Compound Example 41 (the azo compound described in Example 1 of International Publication No. 2005/075572) was used in place of 1.0 parts by weight Except for 0.5 parts by weight of the azo compound in Compound Example 20, the same operation as in Example 3 was carried out to prepare a film containing the azo compound represented by the general formula (1) or a salt thereof, and the azo compound represented by the general formula (3). A polarizing plate is produced simultaneously with the polarizing element of the salt thereof and the azo compound represented by the general formula (4) or the salt thereof, and the produced polarizing plate is used as a measurement sample.

[Example 6]

In addition to using the azo compound represented by the general formula (3) or its salt, the azo compound of Compound Example 54 (the azo compound represented by the formula (21) described in Example 3 of International Publication No. 2012/108169) 1.6 Substituting 0.5 parts by weight of the azo compound of Compound Example 20 was carried out in the same manner as in Example 3 to prepare a film containing the azo compound represented by the general formula (1) or a salt thereof, and a film containing the azo compound represented by the general formula (3). An azo compound or its salt and a polarizing element of the azo compound or its salt represented by the general formula (4), and a polarizing plate are simultaneously produced, and the produced polarizing plate is used as a measurement sample.

[Example 7]

In addition to using 0.58 parts by weight of C.I. direct orange 39 (CAS number: 1325-54-8) having the structure of the aforementioned general formula (4) as the azo compound represented by the general formula (4) or a salt thereof, 0.58 parts by weight of substituted compound example 111 Except for 0.5 parts by weight of the nitrogen compound, the same operation as in Example 3 was carried out to prepare a film containing the azo compound represented by the general formula (1) or its salt, the azo compound represented by the general formula (3) or its salt and the general formula (3). The polarizing element of the azo compound represented by the formula (4) or its salt was prepared simultaneously with a polarizing plate, and the prepared polarizing plate was used as a measurement sample.

[Example 8]

In addition to using 0.12 parts by weight of the azo compound of Compound Example 20 and the azo compound of Compound Example 99 as the azo compound represented by the general formula (3) or a salt thereof (described in Example 1 of International Publication No. 2012/108169) 1.2 parts by weight of the azo compound represented by the formula (17) replaces 0.5 part by weight of the azo compound of the compound example 20, and as the azo compound represented by the general formula (4) or a salt thereof, a compound having the aforementioned general formula (4) was used Structure C.I. Direct Orange 39 (CAS No.: 1325-54-8) 0.39 parts by weight, except that 0.5 parts by weight of the azo compound of Compound Example 111 was replaced by the same operation as in Example 3, to prepare a film containing the general formula (1 ) represented by the azo compound or its salt, the azo compound represented by the general formula (3) or its salt, and the polarizer of the azo compound represented by the general formula (4) or its salt, while producing a polarizing plate, the produced A polarizing plate was used as a measurement sample.

[Example 9]

Except using C.I. direct yellow 28 (0.80 parts by weight) represented by the following structural formula as other organic dyes in place of 0.5 parts by weight of the azo compound of Compound Example 111 which is the azo compound represented by the general formula (4) or its salt, with The same operation as Example 3 was carried out to prepare a film containing the azo compound represented by the general formula (1) or its salt, the azo compound represented by the general formula (3) or its salt, and a film having a polarizing function at almost the same wavelength. The polarizing element of the azo compound represented by the formula (4) or its salt was prepared simultaneously with a polarizing plate, and the prepared polarizing plate was used as a measurement sample.

[Comparative Example 3]

A polarizing element was produced in the same manner as in Example 3, except that the composition of the azo compound in Example 3 was changed to the composition of the azo compound described in Example 2 of Japanese Patent Laid-Open No. 11-218611. A polarizing plate was produced, and the produced polarizing plate was used as a measurement sample.

[Comparative Example 4]

Except having changed the composition of the azo compound in Example 3 to the composition of the azo compound described in Example 3 of Japanese Patent No. 4162334, the same operation as in Example 3 was carried out to produce a polarizing element, and at the same time a polarized light was produced plate, and the prepared polarizing plate was used as a measurement sample.

[Comparative Example 5]

Except having changed the composition of the azo compound in Example 3 to the composition of the azo compound described in Example 1 of Japanese Patent No. 4360100, the same operation as in Example 3 was carried out to produce a polarizing element, and at the same time a polarized light was produced. plate, and the prepared polarizing plate was used as a measurement sample.

[Comparative Example 6]

Except not using the azo compound of the compound example 1 which is the azo compound represented by the general formula (1), the same operation as in Example 3 was carried out to prepare a polarizing element and a polarizing plate, and the prepared polarizing plate was used as the measurement sample.

[Comparative Example 7]

In place of the azo compound represented by the general formula (1), 1.8 parts by weight of the azo compound represented by the formula (17) of International Publication No. 2012/108169 belonging to the tetrazo compound as the azo compound of Compound Example 1 was used. Except for the azo compound of Compound Example 1, the same operation as in Example 3 was carried out to prepare a polarizing element and a polarizing plate, and the prepared polarizing plate was used as a measurement sample.

In Table 2, in the polarizing plates of Examples 3 to 9 and Comparative Examples 3 to 7, the optical sensitivity-corrected single transmittance Ys, the optical sensitivity-corrected parallel position transmittance Yp, and The vertical transmittance Tc, the degree of polarization Py and the contrast value CR corrected by the visual sensitivity.

[Table 2]

Ys(%) Yp(%) Yc(%) Py(%) CR Example 3 40.23 32.33 0.0371 99.89 871 Example 4 40.36 32.54 0.0423 99.87 769 Example 5 40.71 33.11 0.0313 99.91 1058 Example 6 40.44 32.68 0.0236 99.93 1385 Example 7 40.41 32.54 0.1201 99.63 271 Example 8 40.43 32.67 0.0256 99.92 1276 Example 9 40.45 32.56 0.1621 99.50 201 Comparative Example 3 40.38 31.94 0.6756 97.91 47 Comparative Example 4 40.69 32.60 0.5123 98.44 64 Comparative Example 5 40.61 32.09 0.8914 97.26 36 Comparative Example 6 40.53 22.61 10.242 61.36 2 Comparative Example 7 40.45 31.91 0.818 97.47 39

As can be seen from Table 2, when the polarizing plates of Examples 3 to 9 of the present invention are compared with the polarizing plates of Comparative Examples 3 to 7, the polarization performance and contrast are improved. In addition, even when the polarizing plates of Examples 3 to 9 were exposed to an environment of 85°C and a relative humidity of 85% for 500 hours, the transmittance and the degree of polarization did not change.

From the above, it is apparent from the results of Examples 1 to 9 and Comparative Examples 1 to 7 that the polarizing plate and polarizing assembly of the present invention have improved optical properties when compared with conventional polarizing plates and polarizing assemblies. In addition, as apparent from the results of Examples 3 to 9 above, the polarizing plate and the polarizing element of the present invention are highly durable polarizing elements and polarizing plates. In addition, products such as a display device or a polarizing lens using the polarizing element or polarizing plate of the present invention have good polarizing properties and durability, so that high reliability can be obtained.

Claims (15)

1. An azo compound, which is an azo compound represented by the following general formula (1) or a salt thereof:

In the formula, Ab ₁ represents a phenyl group having one or two substituents selected from the group consisting of a sulfonic acid group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms, or A naphthyl group having 2 or 3 substituents selected from the group consisting of a sulfonic acid group, a hydroxyl group and an alkoxy group having a carbon number of 1 to 4 having a sulfonic acid group, Rb ₁ to Rb ₅ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbons, an alkoxy group having 1 to 4 carbons, a sulfonic acid group, or an alkoxy group having a sulfonic acid group having 1 to 4 carbons, Xb ₁ represents a phenylamino group which may have one or two substituents selected from the group consisting of methyl, methoxy, sulfonic acid, amino and alkylamino having 1 to 4 carbon atoms, and may have one or two substituents selected from the group consisting of The benzoylamino group of one substituent in the group consisting of hydroxyl, amino and carboxyethylamino may have a group selected from hydroxyl, alkyl with 1 to 4 carbons, alkoxy with 1 to 4 carbons, amino and 1 to 3 substituted phenylazo groups in the group consisting of carboxyethylamino groups, or naphthotriazolyl groups substituted with 1 or 2 sulfonic acid groups. 2. The azo compound according to claim 1, which is an azo compound represented by the following general formula (2) or a salt thereof:

In the formula, Ab ₁ represents a phenyl group having one or two substituents selected from the group consisting of a sulfonic acid group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms, or A naphthyl group having 2 or 3 substituents selected from the group consisting of a sulfonic acid group, a hydroxyl group and an alkoxy group having a carbon number of 1 to 4 with a sulfonic acid group; Rb ₁ to Rb ₅ independently represent a hydrogen atom, an alkyl group with 1 to 4 carbon atoms, an alkoxy group with 1 to 4 carbon atoms or an alkoxy group with 1 to 4 carbon atoms having a sulfonic acid group; Xb ₁ represents a group selected from methyl, methoxy, sulfonic acid phenylamino group with one or two substituents in the group consisting of an alkylamino group, an amino group and an alkylamino group having 1 to 4 carbon atoms, and may have one substitution selected from the group consisting of a hydroxyl group, an amino group and a carboxyethylamino group benzoylamino group, which may have 1 to 3 substituents selected from the group consisting of hydroxy, alkyl with 1 to 4 carbons, alkoxy with 1 to 4 carbons, amino and carboxyethylamino Phenylazo, or naphthotriazolyl substituted with 1 or 2 sulfonic acid groups. 3 . The azo compound according to claim 1 , wherein Xb ₁ in the general formula (1) may have a group selected from the group consisting of methyl, methoxy, sulfonic acid, amino, and carbon numbers from 1 to 4. 4 . A phenylamino group with one or two substituents in the group consisting of alkylamino groups. 4. The azo compound according to claim 2, wherein Xb ₁ in the general formula (2) may have a group selected from methyl group, methoxy group, sulfonic acid group, amino group and carbon number from 1 to 4 A phenylamino group with one or two substituents in the group consisting of alkylamino groups. 5 . A polarizing element comprising a base material and the azo compound according to claim 1 . 6. The polarizing assembly according to claim 5, further comprising an azo compound represented by the following general formula (3) or a salt thereof:

In the formula, Ar ₁ represents a phenyl group having one or two substituents selected from the group consisting of a sulfonic acid group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms, or A naphthyl group having 2 or 3 substituents selected from the group consisting of a sulfonic acid group, a hydroxyl group and an alkoxy group having a carbon number of 1 to 4 having a sulfonic acid group, Rr ₁ to Rr ₆ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or an alkoxy group having sulfonic acid group having 1 to 4 carbon atoms, Xr ₁ represents a phenylamino group which may have one or two substituents selected from the group consisting of methyl, methoxy, sulfonic acid, amino and alkylamino having 1 to 4 carbon atoms, and may have one or two substituents selected from The benzoylamino group of one substituent in the group consisting of hydroxyl, amino and carboxyethylamino may have a group selected from hydroxyl, alkyl with 1 to 4 carbons, alkoxy with 1 to 4 carbons, amino and phenylazo with 1 to 3 substituents in the group consisting of carboxyethylamino, or naphthotriazolyl substituted with 1 or 2 sulfonic acid groups, m and n independently represent 0 or 1, respectively. 7. The polarizing assembly according to claim 5, further comprising an azo compound represented by the following general formula (4) or a salt thereof:

In the formula, Ay ₁ represents a sulfonic acid group, a carboxyl group, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and Ry ₁ to Ry ₄ independently represent a hydrogen atom, a sulfonic acid group, a carbon number An alkyl group of 1 to 4 or an alkoxy group of 1 to 4 carbon atoms, and p represents an integer of 1 to 3. 8. The polarizing assembly according to claim 6, further comprising an azo compound represented by the following general formula (4) or a salt thereof:

In the formula, Ay ₁ represents a sulfonic acid group, a carboxyl group, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and Ry ₁ to Ry ₄ independently represent a hydrogen atom, a sulfonic acid group, a carbon number An alkyl group of 1 to 4 or an alkoxy group of 1 to 4 carbon atoms, and p represents an integer of 1 to 3. 9. The polarizing assembly of claim 6, wherein, The azo compound represented by the general formula (3) or a salt thereof is an azo compound represented by the following general formula (5) or a salt thereof:

In the formula, Ar ₁ represents a phenyl group having one or two substituents selected from the group consisting of a sulfonic acid group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms, or A naphthyl group having 2 or 3 substituents selected from the group consisting of a sulfonic acid group, a hydroxyl group and an alkoxy group having a carbon number of 1 to 4 with a sulfonic acid group; Rr ₁ to Rr ₆ independently represent a hydrogen atom, Alkyl with 1 to 4 carbons, alkoxy with 1 to 4 carbons or alkoxy with 1 to 4 carbons with sulfonic acid group; Xr ₁ represents a group selected from methyl, methoxy, sulfonic acid phenylamino group with one or two substituents in the group consisting of an alkylamino group, an amino group and an alkylamino group having 1 to 4 carbon atoms, and may have one substitution selected from the group consisting of a hydroxyl group, an amino group and a carboxyethylamino group benzoylamino group, which may have 1 to 3 substituents selected from the group consisting of hydroxy, alkyl with 1 to 4 carbons, alkoxy with 1 to 4 carbons, amino and carboxyethylamino Phenylazo, or naphthotriazolyl substituted with one or two sulfonic acid groups; m and n independently represent 0 or 1, respectively. 10. The polarizing assembly according to claim 6 or 9, wherein one of Rr ₅ and Rr ₆ in the general formula (3) or (5) is an alkoxy group having 1 to 4 carbon atoms, and the other is an alkoxy group having 1 to 4 carbon atoms. An alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. 11. The polarizing assembly according to claim 6 or 9, wherein Xr ₁ in the general formula (3) or (5) may have a group selected from methyl group, methoxy group, sulfonic acid group, amino group and carbon A phenylamino group with one or two substituents in the group consisting of alkylamino groups of 1 to 4, or a benzyl group which may have one substituent selected from the group consisting of hydroxyl, amino and carboxyethylamino Acylamino. 12. The polarizing assembly according to claim 7 or 8, wherein Ay ₁ in the general formula (4) is a carboxyl group or a sulfonic acid group. 13. The polarizing assembly according to any one of claims 5 to 9, wherein the substrate is a film formed of polyvinyl alcohol or a derivative thereof. 14. A polarizing plate comprising the polarizing element according to any one of claims 5 to 13, and a transparent protective layer provided on at least one side of the polarizing element. 15. A display device comprising the polarizing assembly according to any one of claims 5 to 13, or the polarizing plate according to claim 14.