TWI715585B - Azo compound, dye-based polarizing film containing same, and polarizing plate - Google Patents

Abstract

The object of the present invention is to provide a polarizing plate with excellent polarization performance and durability and less color leakage in the visible light region, and a neutral gray polarizing plate for automotive use that is useful as a dichroic pigment Azo compounds.

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

In the formula, A is an alkoxy group with a carbon number of 1 to 5 and/or a sulfonic acid group having a hydrogen atom, a hydroxyl group, a sulfonic acid group, and at least one of R ₁ to R ₄ is a carbon having a sulfonic acid group Alkoxy groups of 1 to 4, and other R ₁ to R ₄ are each independently a hydrogen atom, an alkyl group with 1 to 4 carbons, or an alkoxy group with 1 to 4 carbons.

Description

Azo compounds and dye-based polarizing films and polarizing plates containing them

The present invention relates to novel azo compounds and dye-based polarizing films and polarizing plates containing them.

The polarizing plate with light penetration and shielding function and the liquid crystal with light switching function are the basic components of liquid crystal displays (Liquid Crystal Display: LCD) and other display devices. The application fields of this LCD also range from small devices such as computers and clocks in the early days to notebook personal computers, word processors, LCD projectors, LCD TVs, car navigation, and indoor and outdoor measuring equipment. And it can also be applied to lenses with polarizing function, such as sunglasses with improved visibility, or the application of polarized glasses corresponding to 3D TVs in recent years. For example, the use of the above-mentioned polarizers has gradually expanded, and the conditions of use have also become used under a wide range of conditions from low temperature to high temperature, low humidity to high humidity, low light intensity to high light intensity, so high polarization performance and high light intensity are required. Durable polarizing plate.

At present, the polarizing plate is manufactured by dyeing the polarizing film substrate with iodine or dichroic dyes or being contained in the polarizing film substrate. The polarizing film substrate is, for example, polyvinyl alcohol or its derivatives with stretched alignment. The film or the polyolefin-based film formed by the dehydration of the hydrochloric acid of the polyvinyl chloride film or the dehydration of the polyvinyl alcohol-based film to generate polyolefin and align it. These are substances that greatly affect the polarization characteristics or durability of the polarizer. Although the iodine-based polarizing film using iodine has excellent polarization performance, it is weak in water and heat. When used for a long time under high temperature and high humidity, its durability will be problematic. In order to improve durability, it is considered that there are methods for processing with formalin or an aqueous solution containing boric acid, and using a low-humidity polymer film as a protective film, but the effect is hardly sufficient. On the other hand, a dye-based polarizing film using a dye is superior in moisture resistance and heat resistance compared to an iodine-based polarizing film, but generally the polarization performance is insufficient.

In recent years, in order to improve the vividness of images of liquid crystal displays, images are displayed under high brightness. Since there is a demand for longer battery driving time in hybrid vehicles or mobile terminals equipped with this type of display, liquid crystal display manufacturers need to reduce the power consumption and need to maintain the brightness of the image even if the brightness is reduced. Polarizing plate for the brightness and vividness of colors.

However, in the polarizing film formed by adsorbing several dyes and aligning the polymer film, if there is light leakage (color leakage) of a specific wavelength in the wavelength region of the visible light region, after the polarizing film is loaded on the liquid crystal panel, it will be in the dark state The hue of the liquid crystal display will change below. Therefore, after the polarizing film is loaded on the liquid crystal display device, in order to prevent the specific wavelength in the dark state The discoloration of the liquid crystal display caused by the color leakage, in the neutral color polarizing film that dyes the polymer film or contains several dyes, it is necessary to make the transmittance of the orthogonal position in the wavelength region of the visible light region (positive Cross penetration rate) similarly decreases. In addition, in car-mounted liquid crystal displays, a polarizing plate with no change in polarization degree is required due to the high temperature and high humidity environment in the summer car. In the past, iodine-based polarizers with good polarization performance and neutral gray were used. However, the iodine-based polarizing plate system has the problem of insufficient light resistance, heat resistance, and moisture and heat resistance as described above. In order to solve this problem, dye-based neutral gray polarizers that are dyed or contain multiple types of dichroic dyes are gradually used. Dye-based neutral gray polarizers generally use a combination of the three primary colors of light, namely red, blue, and yellow dyes. However, as mentioned earlier, the polarization performance of the dye-based neutral gray polarizer is not sufficient. Therefore, it is necessary to develop good dichroic dyes corresponding to the polarization properties of the three primary colors.

The characteristics of the dye system are as described earlier, in order to control the components of the three primary colors of light, dyeing or containing respective independent dyes corresponding to this. In recent years, the light sources used in liquid crystal display panels are cold cathode tube method or LED method, but the wavelength of the light source emitted from this is different depending on the method. Even in the same method, there are still many different panels manufactured The situation varies from company to company. Therefore, in the development of dichroic dyes with good polarization properties, the design of dichroic dyes with absorption wavelengths that match the wavelength of the light source is extremely important.

Examples of dyes used in the production of the above-mentioned dye-based polarizing film include water-soluble azo compounds described in Patent Documents 1 to 5 and the like.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 2622748

[Patent Document 2] Japanese Patent Application Publication No. 2001-33627

[Patent Document 3] JP 2009-132794 A

[Patent Document 4] Japanese Patent No. 4270486

[Patent Document 5] Japanese Patent No. 4360100

[Non-Patent Literature]

[Non-Patent Document 1] Dye Chemistry; by Hosoda Toyoda, published by Jihodo, 1957

One of the objectives of the present invention is to provide a high-performance polarizing plate with excellent polarization performance and moisture resistance, heat resistance, and light resistance. In addition, another object of the present invention is to provide a polarizing plate that exhibits neutral gray formed by adsorbing and aligning two or more types of dichroic dyes on a polymer film, and has no color leakage in the orthogonal position in the wavelength region of the visible light region. A high-performance polarizing plate with excellent polarization performance, moisture resistance, heat resistance, and light resistance.

A further purpose is to provide a dye-based neutral gray polarizer for automotive liquid crystal displays. The brightness and polarization performance, durability and light resistance are all Good high performance polarizer.

In order to achieve the objective, the inventors of the present invention have conducted intensive studies and found that the polarizing film and the polarizing plate containing the specific azo compound or its salt have excellent polarization performance, moisture resistance, heat resistance, and light resistance, and then completed the present invention.

That is, the present invention relates to the following:

(式中，A為具有氫原子、羥基、具有磺酸基之碳數1~5之烷氧基及/或磺酸基之萘基，R₁~R₄之至少一個係各自獨立為具有磺酸基之碳數1~4之烷氧基，其他R₁~R₄係各自獨立為氫原子、碳數1~4之烷基或碳數1~4之烷氧基)。 <1> An azo compound represented by the following formula (1) or a salt thereof,

(In the formula, A is an alkoxy group having 1 to 5 carbon atoms with a hydrogen atom, a hydroxyl group, and/or a naphthyl group having a sulfonic acid group, and at least one of R ₁ to R ₄ is each independently a The acid group is an alkoxy group with 1 to 4 carbons, and the other R ₁ to R ₄ are each independently a hydrogen atom, an alkyl group with 1 to 4 carbons or an alkoxy group with 1 to 4 carbons).

<2> The azo compound or its salt according to <1>, which is in the above formula (1), and the other R ₁ to R ₄ are each independently a hydrogen atom, a methyl group or a methoxy group.

<3> The azo compound or its salt such as <1> or <2>, which is (a) R ₁ is an alkoxy group with a sulfonic acid group with carbon numbers of 1 to 4, and (b) R ₃ is a sulfonic acid The acid group has an alkoxy group having 1 to 4 carbon atoms, or (c) R ₁ and R ₃ are each independently an alkoxy group having 1 to 4 carbon atoms having a sulfonic acid group.

<4> The azo compound or its salt as in <1> to <3>, which is in the above formula (1), the lower alkoxy group having a sulfonic acid group is 3-sulfonic acid propoxy group.

(式中，R₅為氫原子、羥基、具有磺酸基之碳數1~5之烷氧基、或磺酸基，n為1~3之整數)。 <5> The azo compound or salt thereof according to any one of <1> to <4>, wherein A is represented by the following formula (2),

(In the formula, R ₅ is a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 5 carbon atoms or a sulfonic acid group, and n is an integer of 1 to 3).

(R₆為氫原子、羥基、及/或具有磺酸基之碳數1~5之烷氧基，R₇~R₁₀之至少一個為具有磺酸基之碳數1~4之烷氧基，其他R₇~R₁₀係各自獨立為氫原子、碳數1~4之烷基或碳數1~4之烷氧基，x為1~3之整數)。 <6> An azo compound represented by the following formula (3) or a salt thereof,

(R ₆ is a hydrogen atom, a hydroxyl group, and/or an alkoxy group with a carbon number of 1 to 5 having a sulfonic acid group, and at least one of R ₇ to R ₁₀ is an alkoxy group with a carbon number of 1 to 4 having a sulfonic acid group , The other R ₇ to R ₁₀ are each independently a hydrogen atom, an alkyl group with 1 to 4 carbons or an alkoxy group with 1 to 4 carbons, and x is an integer of 1 to 3).

<7> The azo compound or its salt as in <6>, which is in the above formula (3), R ₇ ~ R _{10 which} are not alkoxy groups with a sulfonic acid group having 1 to 4 carbon atoms are each independently Hydrogen atom, methyl group, methoxy group.

<8> The azo compound or its salt as in <6> or <7>, which is (a) R ₈ is an alkoxy group with a carbon number of 1 to 4 having a sulfonic acid group, (b) R ₁₀ is a sulfonic acid The acid group has an alkoxy group having 1 to 4 carbon atoms, or (c) R ₈ and R ₁₀ are each independently an alkoxy group having 1 to 4 carbon atoms having a sulfonic acid group.

<9> The azo compound or salt thereof according to any one of <6> to <8>, which is in the above formula (3), R ₆ is a hydrogen atom, and x is 2.

<10> The azo compound or its salt as in any one of <6> to <9>, which is in the above formula (3), the alkoxy group having sulfonic acid groups with 1 to 4 carbon atoms is 3-sulfonic acid Acid group propoxy.

<11> A dye-based polarizing film comprising a polarizing film base material, the polarizing film base material containing the azo compound or its salt as described in any one of <1> to <10>.

<12> A dye-based polarizing film comprising a polarizing film base material, the polarizing film base material containing the azo compound or its salt as in any one of <1>~<10>, and one of the other types The above organic dyes.

<13> The dye-based polarizing film of <11> or <12>, wherein the polarizing film substrate is a film composed of polyvinyl alcohol resin or its derivatives.

<14> A dye-based polarizing plate, which can be obtained by attaching a transparent protective layer to at least one side of the dye-based polarizing film of any one of <11> to <13>.

<15> A polarizing plate for liquid crystal display, which uses the dye-based polarizing film of any one of <11> to <13> or the dye-based polarizing plate of <14>.

<16> A neutral gray polarizing plate for vehicle use, which uses the dye-based polarizing film of any one of <11>~<13>, the dye-based polarizing plate of <14>, or the dye-based polarizing plate of <15> Polarizing plate for liquid crystal display.

<17> A liquid crystal display device, which uses the dye-based polarizer as in <14>, the polarizer for liquid crystal display as in <15>, or the neutral gray polarizer for automotive use as in <16>.

The azo compound of the present invention or its salt is useful as a dye for polarizing films. In addition, the polarizing film containing these compounds has high polarizing performance comparable to that of the polarizing film using iodine, and has excellent durability. Therefore, it is suitable for various liquid crystal displays and liquid crystal projectors. In addition, it is necessary to have high polarization performance and durability for automotive applications, and display applications such as industrial meters used in various environments.

The azo compound of the present invention is represented by the above formula (1). In the above formula (1), A is an alkoxy group with a carbon number of 1 to 5 and/or a sulfonic acid group having a hydrogen atom, a hydroxyl group, a sulfonic acid group, and at least one of R ₁ to R ₄ has a sulfonic acid group. The acid group has an alkoxy group with 1 to 4 carbon atoms, and the other R ₁ to R ₄ are each independently a hydrogen atom, an alkyl group with 1 to 4 carbon atoms, and an alkoxy group with 1 to 4 carbon atoms.

Hereinafter, the compound of the formula (1) will be explained, but in the following substituents and the like, the carbon number of 1 to 4 is referred to as "lower".

In this case, the "substituent" includes a hydrogen atom, but it is simply described as the "substituent".

The structure A in the above formula (1) represents a naphthyl group having a substituent. The substituents are preferably hydrogen atoms, sulfonic acid groups, hydroxyl groups, lower alkoxy groups containing sulfonic acid groups, and sulfonic acid groups. Preferably, A is a naphthyl group represented by the above formula (2), R ₅ represents a hydrogen atom, a hydroxyl group, an alkoxy group having a sulfonic acid group with a carbon number of 1 to 5, or a sulfonic acid group, and n is 1 to 3. In addition, the position of the sulfo group may be on any benzene nucleus of the naphthalene ring. As the lower alkoxy group containing a sulfonic acid group, a linear alkoxy group is preferred, and the substitution position of the sulfonic acid group is preferably at the end of the alkoxy group. Preferred are 3-sulfopropoxy and 4-sulfobutoxy. The substitution position of the substituent of the naphthyl group is not particularly limited. If the number shown in the following formula (4) is used for description, when the number of substituents is 2, the combination of 5-position and 7-position, or 6-position and 8-position is preferred, when there are 3 substituents At this time, 3-position and 5-position and 7-position, 3-position and 6-position and 8-position are preferred.

In the above formula (1), R ₁ to R ₄ may have a substituent, and the substituent is not limited. Preferably, R ₁ to R ₄ each independently represent a hydrogen atom, a lower alkyl group, and a lower alkoxy group, more preferably a hydrogen atom, a methyl group, an ethyl group, a methoxy group, or an ethoxy group, and particularly preferably a hydrogen atom, a methyl group Group, ethyl, lower alkoxy containing sulfonic acid group. As the lower alkoxy group containing a sulfonic acid group in the above formula (1), a linear alkoxy group having a carbon number of 2 to 4 is preferred, and the substitution position of the sulfonic acid group is at the end of the alkoxy group. More preferably, it is 3-sulfopropoxy with 3 carbons and 4-sulfobutoxy with 4 carbons. Particularly preferred is 3-sulfopropoxy with 3 carbon atoms.

The substitution position of R ₁ to R ₄ on the benzene ring is not particularly limited. If the number shown in the following formula (5) is used for description, it is preferably only 2-position, only 5-position, combination of 2-position and 6-position, combination of 2-position and 5-position, 3 A combination of -bit and 5-bit. More preferably, it is only 2-position, 5-position only, combination of 2-position and 5-position. Furthermore, in the foregoing, only the 2-position and only the 5-position system means that only the 2-position or the 5-position has a substituent other than one hydrogen atom. Particularly preferred is a combination of 3-sulfopropoxy groups at the 2-position and other substituents at the 5-position.

Next, specific examples of the azo compound represented by the above formula (1) used in the present invention are listed below. Furthermore, the sulfonic acid group, carboxyl group and hydroxyl group in the formula are expressed as free acids.

The azo compound or its salt represented by the above formula (1) can follow the usual azo dye preparation method as described in Non-Patent Document 1, and by performing diazotization and coupling, as described in Patent Document 3. Easy to manufacture.

The specific manufacturing method is shown below.

By the same manufacturing method as in Non-Patent Document 1, the following formula (i) The amino naphthalenes (naphthyl amines) with substituents shown are diazotized to couple with the anilines of the following formula (ii) to obtain the monoazo shown in the following formula (iii) Amino compound.

[Chemistry 15] A-NH ₂ (i) (In the formula, A represents the same meaning as in the above formula (1).)

(式中，R₁、R₂表示與上述式(1)中者為相同意義。)

(In the formula, R ₁ and R ₂ have the same meaning as those in the above formula (1).)

(式中，A、R₁、R₂表示與上述式(1)中者為相同意義。)

(In the formula, A, R ₁ , and R ₂ have the same meaning as those in the above formula (1).)

Next, this monoazoamine compound (iii) is diazotized, and it is coupled with the aniline of the following formula (iv) twice to obtain the bisazo of the following formula (v) Amino compound.

(式中，R₃、R₄表示與上述式(1)中者為相同意義。)

(In the formula, R ₃ and R ₄ have the same meaning as those in the above formula (1).)

(式中，A、R₁~R₄表示與上述式(1)中者相同意義。)

(In the formula, A, R ₁ to R ₄ have the same meaning as those in the above formula (1).)

The azo compound of the above formula (1) is obtained by reacting this bisazoamino compound (v) with phenyl chloroformate.

In the above reaction, the diazotization step is carried out by the forward method of mixing diazonium components such as hydrochloric acid, sulfuric acid and other mineral acid aqueous solutions or suspensions with sodium nitrite and other nitrites, or by mixing the diazonium components Add nitrite beforehand to the aqueous or weakly alkaline aqueous solution, and perform the reverse method of mixing mineral acid. The appropriate temperature of diazotization is -10~40℃. In addition, the coupling step with anilines is performed by mixing acidic aqueous solutions of hydrochloric acid, acetic acid, and the like with each of the above-mentioned diazonium liquids, and performing acidic conditions with a pH of 2 to 7 at a temperature of -10 to 40°C.

The mono-azoamine-based compound and bis-azoamine-based compound obtained by coupling are taken out directly or by acid precipitation or salting out to precipitate and filter, or it can be carried out to the next step in the state of solution or suspension . When the diazonium salt is poorly soluble and a suspension, it can also be filtered and used as a filter cake in the subsequent coupling step.

Used as primary and secondary coupling with sulfonic acid The specific production method of alkoxy anilines (the above formula (ii) and/or (iv)) is based on the production method shown on page 35 of Patent Document 4 by alkylating phenols with sulfonic acid groups And reduction to obtain sulfonic alkoxy anilines, and can be used in the coupling step.

As a specific method of the ureido reaction of a bisazoamine-based compound and phenyl chloroformate, for example, the preparation method shown on page 57 of Patent Document 3, at a temperature of 10~90℃ and pH7~11 from neutral to Carry out under alkaline conditions. After the reaction, it was precipitated by salting out, filtered, and taken out. If purification is required, repeat salting out or use an organic solvent to precipitate out from water. Examples of the organic solvent used for purification include water-soluble organic solvents such as alcohols such as methanol and ethanol, and ketones such as acetone.

Furthermore, in the present invention, the azo compound represented by the above formula (1) can be used as a free acid, as well as a salt of an azo compound. Examples of such salts include alkali metal salts such as lithium salts, sodium salts, and potassium salts, and organic salts such as ammonium salts and amine salts. Generally, sodium salt is used.

1 of the starting materials for the water-soluble dye represented by the synthesis formula (1) is a naphthylamine with a hydrogen atom, a hydroxyl group, an alkoxy group with 1 to 4 carbon atoms containing a sulfonic acid group, or a sulfonic acid group: A-NH ₂ . Naphthylamines having a hydrogen atom, a hydroxyl group and a sulfonic acid group: Examples of A-NH ₂ include 4-aminonaphthalenesulfonic acid, 7-aminonaphthalene-3-sulfonic acid, and 1-aminonaphthalene- 6-sulfonic acid, 1-aminonaphthalene-7-sulfonic acid, 7-aminonaphthalene-1,3-disulfonic acid, 6-aminonaphthalene-1,3-disulfonic acid, 7-aminonaphthalene- 1,5-disulfonic acid, 7-aminonaphthalene-1,3,6-trisulfonic acid, etc. With 7-aminonaphthalene-3-sulfonic acid, 6-aminonaphthalene-1,3-disulfonic acid, 7-aminonaphthalene-1,4-disulfonic acid, 7-aminonaphthalene-1,5- Disulfonic acid, 2-amino-8-hydroxy-naphthalene-6-sulfonic acid, 3-amino-8-hydroxynaphthalene-6-sulfonic acid, 1-aminonaphthalene-3,6,8-trisulfonic acid , 2-Amino-5-hydroxynaphthalene-1,7-disulfonic acid, 1-aminonaphthalene-3,8-disulfonic acid, etc. are preferred. When synthesizing the compound represented by the formula (2) in A, examples of the naphthylamines having a sulfonic acid group and an alkoxy group having a carbon number of 1 to 5 containing a sulfonic acid group include, for example, 7-amino-3 -(3-sulfopropoxy)naphthalene-1-sulfonic acid, 7-amino-3-(4-sulfobutoxy)naphthalene-1-sulfonic acid, 7-amino-3-( 5-sulfonylpentyloxy)naphthalene-1-sulfonic acid, 7-amino-4-(3-sulfonylpropoxy)naphthalene-2-sulfonic acid, 7-amino-4-(4- Sulfonyl butoxy) naphthalene-2-sulfonic acid, 7-amino-4-(5-sulfonylpentyloxy) naphthalene-2-sulfonic acid, 6-amino-4-(3-sulfonic acid Propoxy) naphthalene-2-sulfonic acid, 6-amino-4-(4-sulfobutoxy) naphthalene-2-sulfonic acid, 6-amino-4-(5-sulfonyl pentyl Oxy)naphthalene-2-sulfonic acid, 2-amino-5-(3-sulfonylpropoxy)naphthalene-1,7-disulfonic acid, 6-amino-4-(3-sulfonic acid Propoxy)naphthalene-2,7-disulfonic acid, 7-amino-3-(3-sulfonylpropoxy)naphthalene-1,5-disulfonic acid, etc.

In the above formula (1), R ₁ to R ₄ in the primary and secondary coupling components may have a substituent, and the substituent is not particularly limited. Preferably, R ₁ to R ₄ each independently represent a hydrogen atom, a lower alkyl group, and a lower alkoxy group, preferably a hydrogen atom, a methyl group, an ethyl group, a methoxy group, or an ethoxy group, and particularly preferably a hydrogen atom, Methyl, ethyl, lower alkoxy containing sulfonic acid group.

The substitution position of R ₁ to R _{4 in} anilines is not limited. The preferred system is only 2-position, only 5-position, combination of 2-position and 6-position, combination of 2-position and 5-position, combination of 3-position and 5-position, especially preferred system is only 2-bit, 5-bit only, combination of 2-bit and 5-bit.

As an example of the aniline of the primary and/or secondary coupler, for example, aniline, 2-methylaniline, 2-ethylaniline, 2-propylaniline, 2-butylbenzene Amine, 3-methylaniline, 3-ethylaniline, 3-propylaniline, 3-butylaniline, 2,5-dimethylaniline, 2,5-diethylaniline, 2-methoxyaniline , 2-ethoxyaniline, 2-propoxyaniline, 2-butoxyaniline, 3-methoxyaniline, 3-ethoxyaniline, 3-propoxyaniline, 3-butoxyaniline, 2-methoxy-5-methylaniline, 2,5-dimethoxyaniline, 3,5-dimethylaniline, 2,6-dimethylaniline or 3,5-dimethoxyaniline, etc. .

As other examples of the anilines of the primary and/or secondary coupler, for example, 3-(2-amino-4-methylphenoxy)propane-1-sulfonic acid, 3-(2-amino Phenoxy)propane-1-sulfonic acid, 4-(2-amino-4-methylphenoxy)butane-1-sulfonic acid, 4-(2-aminophenoxy)butane-1 -Sulfonic acid, 2-(2-amino-4-methylphenoxy)ethane-1-sulfonic acid, 2-(2-aminophenoxy)ethane-1-sulfonic acid, 3-( 3-amino-4-methylphenoxy)propane-1-sulfonic acid, 3-(3-aminophenoxy)propane-1-sulfonic acid, 4-(3-amino-4-methyl Phenoxy)butane-1-sulfonic acid, 4-(3-aminophenoxy)butane-1-sulfonic acid, 2-(3-amino-4-methylphenoxy)ethane- 1-sulfonic acid, 2-(3-aminophenoxy)ethane-1-sulfonic acid, 3-(2-amino-4-methoxyphenoxy)propane-1-sulfonic acid, 4- (2-Amino-4-methoxyphenoxy)butane-1-sulfonic acid, -(2-amino-4-methoxyphenoxy)ethane-1-sulfonic acid, etc., 3- (3-Amino-4-methoxyphenoxy)propane-1-sulfonic acid, 4-(3-amino-4-methoxyphenoxy)butane-1-sulfonic acid, 2-( 3-amino-4-methoxyphenoxy)ethane-1-sulfonic acid, 3-(2-amino-4-ethoxyphenoxy)propane-1-sulfonic acid, 4-(2 -Amino-4-ethoxyphenoxy)butane-1-sulfonic acid, -(2-amino-4-ethoxyphenoxy)ethane-1-sulfonic acid, etc., 3-(3 -Amino-4-ethoxyphenoxy)propane-1-sulfonic acid, 4-(3-amino-4-ethoxyphenoxy)butane-1-sulfonic acid, 2- (3-Amino-4-ethoxyphenoxy)ethane-1-sulfonic acid and the like. Preferably 3-(2-amino-4-methylphenoxy)propane-1-sulfonic acid, 3-(2-aminophenoxy)propane-1-sulfonic acid, 4-(2-amine 4-methylphenoxy)butane-1-sulfonic acid, 4-(2-aminophenoxy)butane-1-sulfonic acid, 2-(2-amino-4-methylbenzene) (Oxy)ethane-1-sulfonic acid, 2-(2-aminophenoxy)ethane-1-sulfonic acid, 3-(3-amino-4-methylphenoxy)propane-1- Sulfonic acid, 3-(3-aminophenoxy)propane-1-sulfonic acid, 4-(3-amino-4-methylphenoxy)butane-1-sulfonic acid, 4-(3- Aminophenoxy)butane-1-sulfonic acid, 2-(3-amino-4-methylphenoxy)ethane-1-sulfonic acid, 2-(3-aminophenoxy)ethane Alkane-1-sulfonic acid, 3-(2-amino-4-methoxyphenoxy)propane-1-sulfonic acid, 4-(2-amino-4-methoxyphenoxy)butane -1-sulfonic acid, -(2-amino-4-methoxyphenoxy)ethane-1-sulfonic acid, 3-(3-amino-4-methoxyphenoxy)propane-1 -Sulfonic acid, 4-(3-amino-4-methoxyphenoxy)butane-1-sulfonic acid, 2-(3-amino-4-methoxyphenoxy)ethane-1 -Sulfuric acid, particularly preferably 3-(2-amino-4-methylphenoxy)propane-1-sulfonic acid, 3-(2-amino-4-methylphenoxy)butane-1 -Sulfonic acid.

The amine groups of these anilines can also be protected. As the protecting group, for example, its ω-methane sulfonate group can be mentioned.

Furthermore, in the dye-based polarizing film or dye-based polarizing plate of the present invention, the azo compound represented by the above formula (1) or its salt may be used alone or in plural, or one or more other organic dyes may be used in combination as necessary. The combined organic dyes are not particularly limited, and dyes having absorption characteristics and high dichroism in a wavelength region different from the absorption wavelength region of the azo compound or its salt of the present invention are preferred. For example, C.I. Direct Yellow 12, CI Direct Yellow 28, CI Direct Yellow 44, CI Direct Orange 26, CI Direct Orange 39, CI Direct Orange 71, CI Direct Orange 107, CI Direct Red 2, CI Direct Red 31, CI Direct Red 79, CI Direct Red 81, CI Direct Red 247, CI Direct Blue 237, CI Direct Blue 273, CI Direct Blue 274, CI Direct Green 80, CI Direct Green 59, and the dyes described in Patent Documents 1 to 5 are used as representative examples. According to the purpose, use such as patent Dyes developed for polarizing plates as described in Documents 1 to 5 are preferred. These pigments are used as free acid, or alkali metal salt (for example, Na salt, K salt, Li salt), ammonium salt, and amine salt.

When necessary, when other organic dyes are used in combination, the purpose of the polarizing film varies according to the neutral color polarizing film, the color polarizing film for liquid crystal projectors, and other color polarizing films. The mixing ratio is not particularly limited, but generally speaking, based on the mass of the azo compound of the above formula (1) or its salt, based on the total of at least one of the aforementioned organic dyes, 0.1-10 parts by mass It is better to use within the range.

It is also possible to align the azo compound represented by the above formula (1) or its salt together with other dyes in a polarizing film substrate (for example, a polymer film) by a known method, or to align it with Liquid crystals are mixed together or aligned by coating methods to produce polarizing films with various colors or neutral colors. The polarizing plate obtained is provided with a protective film, and as a polarizing plate, a protective layer or AR (anti-reflection) layer and a support are provided as necessary, and used in LCD projectors, computers, clocks, notebook personal computers, word processors, LCD TV, car navigation and inside and outside the house Measuring instrument or display, etc., lens or glasses.

The polarizing film substrate (polymer film) used in the dye-based polarizing film of the present invention is preferably a film composed of polyvinyl alcohol resin or its derivatives. Specific examples include polyvinyl alcohol or its derivatives, And any one of these is modified with olefins such as ethylene and propylene, or unsaturated carboxylic acids such as crotonic acid, acrylic acid, methacrylic acid, and maleic acid. From the viewpoint of dye adsorption and alignment, among them, a film composed of polyvinyl alcohol or its derivatives is also suitable. The thickness of the substrate is usually 30-100 μm, preferably about 50-80 μm.

When such a polarizing film substrate (polymer film) contains the azo compound of the above formula (1) or its salt, a method of dyeing the polymer film is usually used. Dyeing is performed by the following operations, for example. First, a dye bath is prepared by dissolving the azo compound or its salt of the present invention and the dye other than necessary in water. The dye concentration in the dye bath is not particularly limited, and is usually selected from the range of 0.001 to 10% by mass. In addition, dyeing auxiliary agents can also be used as necessary. For example, it is suitable to use Glauber's salt at a concentration of about 0.1-10% by mass. The polymer film is immersed in the dye bath prepared therefor for 1 to 10 minutes for dyeing. The dyeing temperature is preferably about 40 to 80°C.

The alignment of the azo compound of the above formula (1) or its salt is implemented by extending the polymer film dyed by the above operation. As a method for stretching, any known methods such as a wet method and a dry method can be used. The extension of the polymer film can also be carried out before dyeing according to the situation. In this case, the water-soluble dye is aligned at the time of dyeing. The polymer film that contains water-soluble dyes and is aligned should be made by known methods. Post-treatment such as boric acid treatment. This post-processing is performed for the purpose of improving the light transmittance and polarization of the polarizing film. The conditions of boric acid treatment vary according to the type of polymer film used or the type of dye used, but generally the boric acid concentration of the boric acid aqueous solution is set to 0.1-15% by mass, preferably in the range of 1-10% by mass. It is implemented by immersing in a temperature range of 30 to 80°C, preferably 40 to 75°C for 0.5 to 10 minutes. In addition, if necessary, an aqueous solution containing a cationic polymer compound can also be used for fix treatment.

The resulting dye-based polarizing film of the present invention can be made into a polarizing plate by laminating a transparent protective film with excellent optical transparency and mechanical strength on one or both sides of the dye-based polarizing film. As the material to form the protective film, for example, cellulose acetate film or acrylic film can be used, as well as fluorine film made of tetrafluoroethylene/hexafluoropropylene copolymer, polyester resin, polyolefin Films composed of resin or polyamide resin. Preferably, a triacetyl cellulose (TAC) film or a cycloolefin-based film is used. The thickness of the protective film is usually 40~200μm.

Examples of adhesives that can be used for bonding polarized films and protective films include polyvinyl alcohol-based adhesives, urethane emulsion-based adhesives, acrylic-based adhesives, polyester-isocyanate-based adhesives, etc. , Suitable for polyvinyl alcohol-based adhesives.

A transparent protective layer can also be provided on the surface of the dye-based polarizer of the present invention. As the protective layer, for example, an acrylic or polysiloxane-based hard coating layer, or a urethane-based protective layer, etc. may be mentioned. Moreover, in order to further improve the light transmittance of the veneer, an AR layer is provided on the protective layer as good. The AR layer can be formed by, for example, vapor deposition or sputtering treatment of silicon dioxide, titanium oxide, etc., and can be formed by coating a thin fluorine-based material. Furthermore, the dye-based polarizing plate of the present invention can also be used as an elliptical polarizing plate to which a retardation plate has been attached.

The dye-based polarizing plate of the present invention constituted by this is characterized by having a neutral color, no cross-position color leakage in the wavelength region of the visible light region, and excellent polarization performance, even under high temperature and high humidity conditions. No discoloration or degradation of polarization performance is caused, and light leakage under orthogonal positions in the visible light region is less.

The neutral gray polarizer for vehicle use of the present invention contains the azo compound represented by the above formula (1) or its salt, and if necessary, contains the aforementioned other organic dyes as dichroic dyes. In addition, the polarizing film used in the color polarizing plate for liquid crystal projectors of the present invention can also be manufactured by the aforementioned manufacturing method. For this, a protective film is added to make a polarizing plate, and a protective layer, AR layer, and support are provided as necessary, and it is used as a neutral gray polarizing plate for automotive use.

As a color polarizer for liquid crystal projectors, the necessary wavelength range of the polarizer (A. When using ultra-high pressure mercury lamp; blue channel uses 420~500nm, green channel 500~580nm, red channel 600~680nm, B. uses 3 primary colors The peak wavelength of the LED lamp; the average light transmittance of the single board in the blue channel is 430~450nm, green channel 520~535nm, red channel 620~635nm) is more than 39%, and the average light transmittance of the orthogonal position is 0.4 % Or less, preferably the average light transmittance of the single plate in the necessary wavelength range of the polarizer is 41% or more, and the average light transmittance of the orthogonal position is 0.3% Below, 0.2% or less is preferable. More preferably, the average light transmittance of the single plate in the necessary wavelength range of the polarizing plate is 42% or more, and the average light transmittance of the orthogonal position is 0.1% or less. The color polarizing plate for liquid crystal projectors of the present invention has brightness and excellent polarization performance as described above.

In addition, the average light transmittance of the single plate is the specific wavelength region when natural light enters one of the polarizers (hereinafter referred to as the polarizer in the case of a single polarizer) that is not provided with an AR layer and a transparent glass plate. The average value of light transmittance. The average light transmittance of the orthogonal position is the average value of the light transmittance in the specific wavelength region when natural light is incident on the two polarizers arranged in the orthogonal position.

The neutral gray polarizer for in-vehicle use of the present invention is preferably a polarizer with an AR layer by providing the aforementioned AR layer on a polarizer composed of a polarizing film and a protective film, and is more preferably attached to a transparent resin, etc. A polarizer with an AR layer and a support on the support is better.

The neutral gray polarizing plate for vehicle use of the present invention is usually used as a polarizing plate with a support. Since the support body will be attached with a polarizing plate, it is preferable to have a flat part, and because it is used for optical purposes, a transparent substrate is preferable. Transparent substrates are roughly divided into inorganic substrates and organic substrates. Examples include inorganic substrates such as soda glass, borosilicate glass, crystal substrates, sapphire substrates, spinel substrates, etc., or acrylic, polycarbonate, and polyterephthalate. Organic substrates such as ethylene naphthalate, polyethylene naphthalate, and cycloolefin polymers, but organic substrates are preferred. The thickness or size of the transparent substrate can be a desired size. In addition, in order to increase the light transmittance of the single-plate polarizer with a transparent substrate, it is installed on one or both of the support surface or the polarizer surface. AR layer is better.

When manufacturing a color polarizing plate with a support for in-vehicle use, for example, a transparent adhesive (adhesive) is applied to the flat surface of the support, and then the dye-based polarizing plate of the present invention is stuck on the coated surface. In addition, a transparent adhesive (adhesive) agent may be coated on the polarizing plate, and then the support may be attached to the coated surface. The adhesive (adhesive) used here is preferably, for example, acrylic. Furthermore, when this polarizing plate is used as an elliptical polarizing plate, the retardation plate side is usually attached to the support side, but the polarizing plate side may be attached to the transparent substrate.

That is, in a liquid crystal display for automotive use using the dye-based polarizing plate of the present invention, the dye-based polarizing plate of the present invention is arranged on either or both of the incident side or the output side of the liquid crystal cell. The polarizing plate may be in contact with the liquid crystal cell or not, but from the viewpoint of durability, it is better not to contact. When the polarizing plate is in contact with the liquid crystal cell on the exit side, the dye-based polarizing plate of the present invention using the liquid crystal cell as a support can be used. When the polarizing plate is not in contact with the liquid crystal cell, it is better to use the dye-based polarizing plate of the present invention using a support other than the liquid crystal cell. Furthermore, from the viewpoint of durability, it is better to arrange the dye-based polarizing plate of the present invention on either the incident side or the exit side of the liquid crystal cell, and to arrange the polarizing plate surface of the dye-based polarizing plate of the present invention on the liquid crystal On the unit side, it is better to arrange the support surface on the light source side. Furthermore, the incident side of the liquid crystal cell refers to the light source side, and the opposite side is called the exit side.

In the vehicle-mounted liquid crystal display using the dye-based polarizing plate of the present invention, the liquid crystal cell used is, for example, an active matrix type and It is preferable to seal the liquid crystal between the transparent substrate on which the electrodes and the TFT are formed and the transparent substrate on which the counter electrode is formed. The light emitted by a light source such as a cold cathode tube lamp or a white LED passes through a neutral gray polarizer, and then passes through a liquid crystal cell, a color filter, and a neutral gray polarizer to be projected on the display screen.

The neutral gray polarizer for in-vehicle use constituted by this is characterized by excellent polarization performance and does not cause discoloration or degradation of polarization performance even under high temperature and high humidity in the vehicle.

[Example]

Hereinafter, the present invention will be described in more detail with examples, but these are only examples, and do not limit the present invention in any way. The% and parts in the examples are quality standards unless otherwise specified.

(Example 1)

30.3 parts of 7-aminonaphthalene-1,3-disulfonic acid was added to 400 parts of water and dissolved with sodium hydroxide. 10.4 parts of 35% hydrochloric acid were added, followed by 6.9 parts of sodium nitrite, and stirred for 1 hour. To this, add 24.5 parts of 3-(2-amino-4-methylphenoxy)propane-1-sulfonic acid dissolved in water, stir at 30-40°C while adding sodium carbonate to make pH 5, then Stirring was performed to complete the coupling reaction, and 50.4 parts of the monoazoamine compound represented by the following formula (30) was obtained.

After dispersing 50.4 parts of the monoazo compound of the above formula (79) in 600 parts of water, 9.4 parts of 35% hydrochloric acid was added, followed by 6.2 parts of sodium nitrite, and the mixture was stirred at 25-30°C for 2 hours for diazotization. To this, add 22 parts of 3-(2-amino-4-methylphenoxy)propane-1-sulfonic acid dissolved in water, stir at 30-40°C while adding sodium carbonate to make pH 5, and then Stirring was performed to complete the coupling reaction, and 65.3 parts of the bisazoamino compound represented by the following formula (80) was obtained.

Add 65.3 parts of the obtained bisazoamine compound to 250 parts of water, dissolve it with sodium hydroxide, and stir 6.2 parts of phenyl chloroformate at 30 to 70° C. for 2 hours for ureidolation. Salting out was performed with sodium chloride, and filtration was performed to obtain 41.4 parts of the azo compound of the present invention represented by the above formula (6). The maximum absorption wavelength of this compound in 20% pyridine aqueous solution is 486nm.

(Example 2)

Except that 7-aminonaphthalene-1,3-disulfonic acid was changed to 30.3 parts of 6-aminonaphthalene-1,3-disulfonic acid in Example 1, the same operation as in Example 1 was performed to obtain the above formula (7) 41.4 parts of the azo compound of the present invention shown in (7). The maximum absorption wavelength of this compound in 20% pyridine aqueous solution is 480nm.

(Example 3)

Except that 7-aminonaphthalene-1,3-disulfonic acid was changed to 30.3 parts of 7-aminonaphthalene-1,5-disulfonic acid in Example 1, the same operation as in Example 1 was performed to obtain the above formula (8) 41.4 parts of the azo compound of the present invention shown in (8). The maximum absorption wavelength of this compound in 20% pyridine aqueous solution is 523nm.

(Example 4)

Except that 7-aminonaphthalene-1,3-disulfonic acid was changed to 22.3 parts of 6-aminonaphthalene-2-sulfonic acid in Example 1, the same operation as in Example 1 was performed to obtain the above formula (9) The shown azo compound of the present invention is 41.4 parts. The maximum absorption wavelength of this compound in 20% pyridine aqueous solution is 466nm.

(Example 5)

The same operation was performed as in the primary coupling of the above-mentioned Example 1 to obtain 50.4 parts of the monoazoamino compound represented by the above-mentioned formula (79).

After dispersing 50.4 parts of the monoazo compound of the above formula (79) in 600 parts of water, add 9.4 parts of 35% hydrochloric acid, and then add sodium nitrite 6.2 parts, stirred at 25~30°C for 2 hours for diazotization. To this, 10.9 parts of 2,5-dimethylaniline was added, stirred at 30-40°C and sodium carbonate was added at the same time to make pH3, and then stirred to complete the coupling reaction, and the following formula (81) was obtained. 55.3 parts of bisazoamino compound.

Add 55.3 parts of the obtained bisazoamine compound to 250 parts of water, dissolve it with sodium hydroxide, and stir 6.2 parts of phenyl chloroformate at 30 to 70° C. for 2 hours for ureidolation. Salting out was performed with sodium chloride, and filtration was performed to obtain 35.2 parts of the azo compound of the present invention represented by the above formula (30). The maximum absorption wavelength of this compound in 20% pyridine aqueous solution is 455nm.

(Example 6)

Except that in Example 5, 2,5-dimethylaniline was changed to 9.8 parts of 2-methoxyaniline, the other operations were the same as in Example 5 to obtain the azo compound of the present invention represented by the above formula (31) 35.3 copies. The maximum absorption wavelength of this compound in 20% pyridine aqueous solution is 480nm.

(Example 7)

Except that in Example 5, 7-aminonaphthalene-1,3-disulfonic acid was changed to 6-amine 30.3 parts of methylnaphthalene-1,3-disulfonic acid, except that 2,5-dimethylaniline was changed to 3-methylaniline, and the other operations were the same as in Example 5 to obtain the formula represented by the above formula (32) 34.5 parts of the azo compound of the invention. The maximum absorption wavelength of this compound in 20% pyridine aqueous solution is 452nm.

(Example 8)

30.3 parts of 7-aminonaphthalene-1,3-disulfonic acid was added to 400 parts of water and dissolved with sodium hydroxide. 10.4 parts of 35% hydrochloric acid were added, followed by 6.9 parts of sodium nitrite, and stirred for 1 hour. To this, add 12.1 parts of 2,5-dimethylaniline, stir at 30~40℃ and add sodium carbonate to make pH5, then stir to complete the coupling reaction, and obtain the form shown in the following formula (82) 39.2 parts of azoamine-based compounds.

After dispersing 50.4 parts of the monoazo compound of the above formula (82) in 600 parts of water, 9.4 parts of 35% hydrochloric acid was added, followed by 6.2 parts of sodium nitrite, and the mixture was stirred at 25-30° C. for 2 hours for diazotization. To this, add 19.6 parts of 3-(2-amino-4-methylphenoxy)propane-1-sulfonic acid, stir at 30-40°C and add sodium carbonate at the same time to make pH 5, and then stir for coupling reaction After finishing, 55.3 parts of the bisazoamino compound represented by the following formula (83) was obtained.

Add 55.3 parts of the obtained bisazoamine compound to 250 parts of water, dissolve it with sodium hydroxide, and stir 6.2 parts of phenyl chloroformate at 30 to 70° C. for 2 hours for ureidolation. Salting out was performed with sodium chloride, and filtration was performed to obtain 35.2 parts of the azo compound of the present invention represented by the above formula (52). The maximum absorption wavelength of this compound in 20% pyridine aqueous solution is 463nm.

(Example 9)

Except that 7-aminonaphthalene-1,3-disulfonic acid was changed to 6-amino-4-(3-sulfopropoxy)naphthalene-2-sulfonic acid in Example 8, the others are the same as those in the examples 8 The same operation was performed to obtain 35.3 parts of the azo compound of the present invention represented by the above formula (53). The maximum absorption wavelength of this compound in 20% pyridine aqueous solution is 480nm.

(Example 10)

Except that 2,5-dimethylaniline was changed to 2-methoxyaniline in Example 8, the other Example 8 was performed in the same manner to obtain 35.3 parts of the azo compound of the present invention represented by the above formula (54). The maximum absorption wavelength of this compound in 20% pyridine aqueous solution is 486nm.

(Example 11)

Except that 7-aminonaphthalene-1,3-disulfonic acid was changed to 7-aminonaphthalene-1,5-disulfonic acid in Example 8, the same operation as in Example 8 was performed to obtain the above formula (55 35.7 parts of the azo compound of the present invention shown in ). The maximum absorption wavelength of this compound in 20% pyridine aqueous solution is 452nm.

(Example 12)

Except that 2,5-dimethylaniline was changed to 2,5-dimethoxyaniline in Example 8, the other operations were the same as Example 8 to obtain the azo of the present invention represented by the above formula (56) 36.8 parts of compound. The maximum absorption wavelength of this compound in 20% pyridine aqueous solution is 510nm.

(Example 13)

Except that 7-aminonaphthalene-1,3-disulfonic acid was changed to 6-aminonaphthalene-1,3-disulfonic acid in Example 8, the same operation as in Example 8 was performed to obtain the above formula (57 35.2 parts of the azo compound of the present invention shown in ). The maximum absorption wavelength of this compound in 20% pyridine aqueous solution is 453nm.

(Example 14)

Except that 2,5-dimethylaniline was changed to 2-methoxy-5-methylaniline in Example 8, the other operations were performed in the same manner as Example 8 to obtain the invention represented by the above formula (58) 36.8 parts of azo compounds. The maximum absorption wavelength of this compound in 20% pyridine aqueous solution is 487nm.

(Example 15)

The compound of the above formula (6) obtained in Preparation Example 1 was immersed in a 45°C aqueous solution with a concentration of 0.03% and a 0.1% concentration of Glauber's salt, and polyvinyl alcohol having a thickness of 75 μm was immersed for 4 minutes. In a 3% boric acid aqueous solution, the film was stretched to 5 times at 50°C, and washed and dried under tension to obtain the polarizing film of the present invention.

The polarizing film obtained has a maximum absorption wavelength of 526nm, a polarization rate of 99.9%, and a high polarization rate.

(Example 16)

A polyvinyl alcohol film with a thickness of 75 μm was immersed in an aqueous solution of 0.03% of the compound of the above formula (30) obtained in Example 5 and 0.1% of Glauber's salt at 45°C for 4 minutes. In a 3% boric acid aqueous solution, the film was stretched to 5 times at 50°C, and washed and dried under tension to obtain the polarizing film of the present invention.

The polarizing film obtained has a maximum absorption wavelength of 494nm, a polarization rate of 99.9%, and a high polarization rate.

(Example 17)

A polyvinyl alcohol film with a thickness of 75 μm was immersed in a 45°C aqueous solution of 0.03% of the compound of the above formula (52) obtained in Example 8 and 0.1% of Glauber's salt for 4 minutes. In a 3% boric acid aqueous solution, the film was stretched to 5 times at 50°C, and washed and dried under tension to obtain the polarizing film of the present invention.

The polarizing film obtained has a maximum absorption wavelength of 502nm, a polarization rate of 99.9%, and a high polarization rate.

Furthermore, the test method is described below.

The measurement of the maximum absorption wavelength of the polarizing film and the calculation of the polarization rate are calculated by using a spectrophotometer (U-4100 made by Hitachi, Ltd.) to measure the parallel transmittance and orthogonal transmittance when polarized light is incident.

Here, the parallel transmittance (Ky) refers to the transmittance when the absorption axis of the absolute polarizer and the absorption axis of the polarizing film are parallel, and the orthogonal transmittance (Kz) refers to the absorption axis of the absolute polarizer and the absorption axis of the polarizing film It is the transmittance when orthogonal.

The parallel transmittance and orthogonal transmittance of each wavelength are measured at 380 to 780 nm at intervals of 1 nm. Using the individually measured values, calculate the polarization rate of each wavelength by the following formula (i) to obtain the maximum polarization rate and its maximum absorption wavelength (nm) at 380 to 780 nm.

Polarization rate (%)=[(Ky-Kz)/(Ky+Kz)]×100 (i)

(Examples 18-20)

Except for replacing the compound of the above formula (6) and using the azo compounds described in Examples 2 to 4 (the compounds of the above formulas (7) to (9)), the other operations are the same as in Example 15 to obtain the polarized light of the present invention membrane. The maximum absorption wavelength and polarization rate of the obtained polarizing film are shown in Table 1.

As shown in Table 1, the polarizing films made using these compounds all have high polarization rates.

(Examples 21 and 22)

Except that instead of the above formula (30), the azo compounds described in Examples 6 and 7 (the compounds of the above formulas (31) and (32)) were used, the other operations were the same as in Example 16 to obtain the polarizing film of the present invention. The maximum absorption wavelength and polarization rate of the obtained polarizing film are shown in Table 1.

As shown in Table 1, the polarizing films made using these compounds all have high polarization rates.

(Examples 23-28)

Except that instead of the compound of the above formula (52), the azo compounds described in Examples 9 to 14 (the compounds of the above formulas (53) to (58)) are used instead, the other operations are the same as in Example 17 to obtain the polarized light of the present invention membrane. The maximum absorption wavelength and polarization rate of the obtained polarizing film are shown in Table 1.

As shown in Table 1, the polarizing films made using these compounds all have high polarization rates.

(Test example)

As an indicator of image quality, there is a comparison of the difference in brightness between white display and black display. Examples 15 and 18-20; 16, 21 and 22; and 17 and 23-28 of the polarizing film obtained The maximum absorption wavelength and the comparison at this time are shown in Table 2. Contrast here means parallel transmission The ratio of the transmission rate to the orthogonal transmittance (contrast = parallel transmittance at the maximum absorption wavelength (Ky)/straight transmittance (Kz) at the maximum absorption wavelength). The larger the value, the better the polarization performance of the polarizer. In addition, the evaluation of the polarization performance is to prepare samples and compare them in such a way that the parallel transmittance of the maximum absorption wavelength of the polarizing film becomes the same. As shown in Table 2, the polarizing films made using these compounds all have high contrast.

(Comparative example 1)

Except for replacing the compound of the present invention, the compound (4) in Patent Document 4, which was synthesized in the same manner as the method described in Example 2 of Patent Document 4, was used, and the polarizing film was formed in the same manner as in Example 15 of the present invention. Calculate the contrast. As shown in Table 2, compared to Comparative Example 1, the compounds of the present invention all exhibit high contrast and excellent polarization performance.

(Comparative example 2)

Instead of the compound of the present invention, a compound (I-3) synthesized in the same manner as the method described in [0077] in Patent Document 5 was used, and a polarizing film was formed in the same manner as in Example 15 of the present invention, and the comparison was calculated. As shown in Table 2, compared to Comparative Example 2, the compounds of the present invention all exhibit high contrast and excellent polarization performance.

(Example 29)

Except that the compound (6) obtained in Example 1 was used as a dye 0.2%, CI Direct Orange 39 0.07%, CI Direct Blue 274 0.02%, and Glauber's salt 0.1% concentration 45°C aqueous solution, the other operations were the same as in Example 15 And make a polarizing film. The maximum absorption wavelength of the polarized film obtained is The average transmittance of the single plate under 576nm, 380~600nm is 42%, the average light transmittance of the orthogonal position is 0.02%, and it has a high degree of polarization.

On both sides of this polarizing film, a triacetyl cellulose film (TAC film; manufactured by Fuji Film Co., Ltd.; trade name TD-80U) was laminated via an adhesive of polyvinyl alcohol aqueous solution, and an AR support was obtained by using an adhesive The dye-based polarizer of the present invention (neutral gray polarizer). The polarizing plate of the present invention has a high polarization rate, and exhibits long-term durability even in a high temperature and high humidity state. It also has excellent light fastness for long-term exposure.

(Example 30)

Except that the compound (30) obtained in Example 5 was used as a dye 0.2%, CI Direct Orange 39 0.07%, CI Direct Blue 274 0.02%, and Glauber's salt 0.1% concentration 45°C aqueous solution, the other operations were the same as in Example 16. And make a polarizing film. The maximum absorption wavelength of the obtained polarizing film is 577nm, the average transmittance of the single plate under 380~600nm is 42%, the average light transmittance of the orthogonal position is 0.02%, and it has a high degree of polarization.

On both sides of this polarizing film, a triacetyl cellulose film (TAC film; manufactured by Fuji Film Co., Ltd.; trade name TD-80U) was laminated via an adhesive of polyvinyl alcohol aqueous solution, and an AR support was obtained by using an adhesive The dye-based polarizer of the present invention (neutral gray polarizer). The polarizing plate of the present invention has a high polarization rate, and exhibits long-term durability even in a high temperature and high humidity state. It also has excellent light fastness for long-term exposure.

Example 31

Except that the compound (52) obtained in Example 8 was used as a dye 0.2%, CI Direct Orange 39 0.07%, CI Direct Blue 274 0.02%, and Glauber's salt 0.1% concentration 45°C aqueous solution, the other operations were the same as in Example 17 And make a polarizing film. The maximum absorption wavelength of the obtained polarizing film is 575nm, the average transmittance of the single plate under 380~600nm is 42%, the average light transmittance of the orthogonal position is 0.02%, and it has a high degree of polarization.

On both sides of this polarizing film, a triacetyl cellulose film (TAC film; manufactured by Fuji Film Co., Ltd.; trade name TD-80U) was laminated via an adhesive of polyvinyl alcohol aqueous solution, and an AR support was obtained by using an adhesive The dye-based polarizer of the present invention (neutral gray polarizer). The polarizing plate of the present invention has a high polarization rate, and exhibits long-term durability even in a high temperature and high humidity state. It also has excellent light fastness for long-term exposure.

Claims (17)

An azo compound represented by the following formula (1) or its salt;

In the formula, A is an alkoxy group with a carbon number of 1 to 5 and/or a sulfonic acid group having a hydrogen atom, a hydroxyl group, a sulfonic acid group, and at least one of R ₁ to R ₄ is independently a sulfonic acid The group is an alkoxy group with 1 to 4 carbon atoms, and the other R ₁ to R ₄ are each independently a hydrogen atom, an alkyl group with 1 to 4 carbon atoms or an alkoxy group with 1 to 4 carbon atoms. The azo compound or its salt according to claim 1, which is in the above formula (1), wherein the other R ₁ to R ₄ are each independently a hydrogen atom, a methyl group or a methoxy group. The azo compound or its salt according to claim 1 or 2, wherein (a) R ₁ is an alkoxy group having a sulfonic acid group with carbon number of 1 to 4, and (b) R ₃ is a sulfonic acid group having carbon number 1 ~4 alkoxy group, or (c) R ₁ and R ₃ are each independently an alkoxy group having 1 to 4 carbon atoms having a sulfonic acid group. For example, the azo compound of claim 1 or 2 or its salt, which is in the above formula (1), the alkoxy group having 1 to 4 carbon atoms having a sulfonic acid group is 3-sulfopropoxy group. The azo compound or its salt according to claim 1 or 2, wherein A is represented by the following formula (2);

In the formula, R ₅ is a hydrogen atom, a hydroxyl group, an alkoxy group having a carbon number of 1 to 5 having a sulfonic acid group, or a sulfonic acid group, and n is an integer of 1 to 3. An azo compound represented by the following formula (3) or its salt;

R ₆ is a hydrogen atom, a hydroxyl group, and/or an alkoxy group with a carbon number of 1 to 5 having a sulfonic acid group, at least one of R ₇ to R ₁₀ is an alkoxy group with a carbon number of 1 to 4 having a sulfonic acid group, Other R ₇ to R ₁₀ are each independently a hydrogen atom, an alkyl group with 1 to 4 carbons, or an alkoxy group with 1 to 4 carbons, and x is an integer of 1 to 3. For example, the azo compound or its salt of claim 6, which is in the above formula (3), and R ₇ to R _{10 which} are not alkoxy groups with a sulfonic acid group having 1 to 4 carbon atoms are each independently a hydrogen atom, Methyl, methoxy. The azo compound or salt thereof according to claim 6 or 7, wherein (a) R ₈ is an alkoxy group having a sulfonic acid group with carbon numbers of 1 to 4, and (b) R ₁₀ is a sulfonic acid group having carbon number 1 ~4 alkoxy group, or (c) R ₈ and R ₁₀ are each independently an alkoxy group having 1 to 4 carbon atoms having a sulfonic acid group. The azo compound or its salt according to claim 6 or 7, which is in the above formula (3), R ₆ is a hydrogen atom, and x is 2. The azo compound or its salt according to claim 6 or 7, which is in the above formula (3), the alkoxy group having 1 to 4 carbon atoms having a sulfonic acid group is 3-sulfopropoxy group. A dye-based polarizing film comprising a polarizing film base material, the polarizing film base material containing an azo compound or a salt thereof according to any one of claims 1-10. A dye-based polarizing film comprising a polarizing film substrate containing the azo compound or salt thereof according to any one of claims 1 to 10, and one type other than the aforementioned azo compound or salt thereof The above organic dyes. The dye-based polarizing film of claim 11 or 12, wherein the polarizing film base material is a film composed of polyvinyl alcohol resin or a derivative thereof. A dye-based polarizing plate, which can be obtained by attaching a transparent protective layer to at least one side of the dye-based polarizing film of any one of claims 11 to 13. A polarizing plate for liquid crystal display, which uses the dye-based polarizing film of any one of claims 11 to 13 or the dye-based polarizing plate of claim 14. A polarizing plate with neutral gray for vehicle use, which uses the dye-based polarizing film of any one of claims 11 to 13, the dye-based polarizing plate of claim 14, or the liquid crystal display of claim 15 Polarizing plate. A liquid crystal display device which uses the dye-based polarizing plate of claim 14, the polarizing plate of liquid crystal display of claim 15, or the polarizing plate of neutral gray for automotive use as claimed in claim 16.