TW201708412A - Azo compound, dye-based polarizing film containing same, and polarizing plate - Google Patents

Abstract

The purpose of the present invention is to provide azo compounds that are useful as a dichroic pigment for use in a polarizing plate that has excellent polarizing performance and durability and that causes little color leakage in the visible light region and in a neutral-gray polarizing plate that is for onboard use in a vehicle and that uses the abovementioned polarizing plate. An azo compound represented by formula (1) or a salt thereof. (In the formula, A is a hydrogen atom, a hydroxy group, a C1-5 alkoxy group that has a sulfo group, and/or a naphthyl group that has a sulfo group, one or more of R1-R4 are a C1-4 alkoxy group that has a sulfo group, and the other R1-R4 are each independently a hydrogen atom, a C1-4 alkyl group, or a C1-4 alkoxy group).

Description

Azo compound, dye-containing polarizing film containing the same, and polarizing plate

The present invention relates to a novel azo compound, a dye-based polarizing film containing the same, and a polarizing plate.

A polarizing plate having a light penetration and a shielding function is a basic component of a display device such as a liquid crystal display (LCD) together with a liquid crystal having a light switching function. The application fields of this LCD are also from small computers such as computers and clocks in the early days, to notebook computers, word processors, liquid crystal projectors, LCD TVs, car navigation systems, and measurement devices inside and outside. It can also be applied to lenses having a polarizing function, such as sunglasses having improved visibility, or applications in polarized glasses such as 3D televisions in recent years. As the use of the above polarizing plate is gradually widened, the use conditions are also used under a wide range of conditions of low temperature to high temperature, low humidity to high humidity, low light amount to high light quantity, so high polarization performance is required and high. Durable polarizing plate.

Now, the polarizing plate is made by dyeing a polarizing film substrate using iodine or a dichroic dye or being contained in a polarizing film substrate, such as a polyvinyl alcohol or a derivative thereof which is extended and aligned. The film or a polyalkylene film obtained by dehydrating a polyvinyl chloride film or dehydrating a polyvinyl alcohol film to form a polyolefin. These are substances which have a large influence on the polarization characteristics or durability in the polarizing plate. Although the iodine-based iridium polarizing film is excellent in polarizing performance, water and heat are weak, and when it is used for a long period of time in a state of high temperature and high humidity, there is a problem in durability. In order to improve the durability, it is considered that there is a method in which a treatment with an aqueous solution containing boric acid or a boric acid is used, and a polymer film having a low moisture permeability is used as a protective film, but the effect is difficult. On the other hand, the dye-based polarizing film using a dye is superior in moisture resistance and heat resistance to an iodine-based polarizing film, but generally has insufficient polarizing performance.

In recent years, in order to improve the vividness of liquid crystal display images, image display is performed under high brightness. In order to reduce the driving time of the battery in a hybrid electric vehicle or a mobile terminal equipped with such a display, the liquid crystal display manufacturer needs to maintain the brightness of the image even if the brightness is lowered in order to reduce the power consumption. A polarizer with a sharpness of color and color.

However, in a polarizing film in which a plurality of dyes are adsorbed by a polymer film, light leakage at a specific wavelength (color leakage) occurs in a wavelength region of a visible light region, and the polarizing film is mounted on a liquid crystal panel, and is in a dark state. Below, there will be a change in the hue of the liquid crystal display. 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 polarizing film which dyes the polymer film or contains a plurality of dyes and becomes an intermediate color, it is necessary to make the transmittance of the orthogonal position in the wavelength region of the visible light region (positive The cross penetration rate is similarly lowered. Further, in the in-vehicle liquid crystal display, since the summer car becomes a high-temperature and high-humidity environment, a polarizing plate having no change in polarization degree is also required. In the past, an iodine-based polarizing plate having a good polarizing property and exhibiting neutral ash was used. However, the iodine-based polarizing plate has a problem of insufficient light resistance, heat resistance, and moist heat resistance as described above. In order to solve this problem, it has become increasingly possible to use a dye-based neutral gray polarizing plate which is dyed or contains a plurality of kinds of dichroic dyes. The dye-based neutral gray polarizing plate is generally used in combination with the three primary colors of light, namely, red, blue, and yellow dyes. However, as previously described, the polarizing performance of the dye-based neutral gray polarizing plate is not sufficient. Therefore, it is necessary to develop a dichroic dye which is excellent in polarizing performance for each of the three primary colors.

The dye system is characterized in that, as previously described, in order to control the components of the three primary colors of light, the dyes are dyed or contain separate dyes corresponding thereto. In recent years, the light source used in the liquid crystal display panel has a cold cathode tube method or an LED method, but the wavelength of the light source emitted therefrom is different depending on the mode, and even in the same manner, many of them are manufactured according to the respective panels. The company is different. Therefore, in the development of dichroic dyes having good polarizing performance, it is extremely important to design a dichroic dye having an absorption wavelength in accordance with the wavelength of the light source.

The dye used in the production of the above-mentioned dye-based polarizing film is, for example, a water-soluble azo compound described in Patent Documents 1 to 5 and the like.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 2622748

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

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2009-132794

[Patent Document 4] Japanese Patent No. 4270486

[Patent Document 5] Japanese Patent No. 4360100

[Non-patent literature]

[Non-Patent Document 1] Dye Chemistry; Hosokawa, Technology Report, 1957

One of the objects of the present invention is to provide a high-performance polarizing plate having excellent polarizing performance, moisture resistance, heat resistance and light resistance. Further, another object of the present invention is to provide a polarizing plate which exhibits neutral ash by adsorbing two or more kinds of dichroic dyes on a polymer film, and has no orthogonal color leakage in a wavelength region of a visible light region. High-performance polarizer with excellent polarizing performance, moisture resistance, heat resistance and light resistance.

A further object is to provide a dye-based neutral gray polarizing plate for a vehicle-mounted liquid crystal display, which has brightness, polarization performance, durability and light resistance. Good high performance polarizer.

In order to achieve the object, the inventors of the present invention have found that a polarizing film containing a specific azo compound or a salt thereof and a polarizing plate have excellent polarizing performance, moisture resistance, heat resistance, and light resistance, and have completed the present invention.

That is, the present invention relates to the following:

<1> an azo compound represented by the following formula (1) or a salt thereof, (In the formula, A is a naphthyl group having a hydrogen atom, a hydroxyl group, an alkoxy group having a sulfonic acid group of 1 to 5 carbon atoms, and/or a sulfonic acid group, and at least one of R ₁ to R ₄ is independently a sulfonate. The acid group has an alkoxy group having 1 to 4 carbon atoms, and the other R ₁ to R ₄ groups are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms.

<2> The azo compound according to <1> or a salt thereof, wherein the other R ₁ to R ₄ are each independently a hydrogen atom, a methyl group or a methoxy group.

<3> The azo compound of <1> or <2> or a salt thereof, wherein (a) R ₁ is an alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms, and (b) R ₃ is a sulfo group; The alkoxy group having 1 to 4 carbon atoms of the acid group, or (c) R ₁ and R ₃ each independently is an alkoxy group having 1 to 4 carbon atoms having a sulfonic acid group.

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

The azo compound or a salt thereof according to any one of <1> to <4>, wherein A is represented by the following formula (2), (wherein R ₅ is a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 5 carbon atoms having a sulfonic acid group, or a sulfonic acid group, and n is an integer of 1 to 3).

<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 having a sulfonic acid group having 1 to 5 carbon atoms; and at least one of R ₇ to R ₁₀ is an alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms; Further, the other R ₇ to R ₁₀ groups are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and x is an integer of 1 to 3).

<7> The azo compound or a salt thereof according to <6>, which is not in the above formula (3), is not independently a R ₇ to R ₁₀ group having an alkoxy group having 1 to 4 carbon atoms of a sulfonic acid group. Hydrogen atom, methyl group, methoxy group.

<8> The azo compound of <6> or <7> or a salt thereof, wherein (a) R ₈ is an alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms, and (b) R ₁₀ is a sulfonate. The alkoxy group having 1 to 4 carbon atoms of the acid group, or (c) R ₈ and R ₁₀ each independently is an alkoxy group having 1 to 4 carbon atoms having a sulfonic acid group.

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

The azo compound or a salt thereof according to any one of <6> to <9>, wherein the alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms is 3-sulfonate in the above formula (3) Acidic propoxy.

<11> A dye-based polarizing film comprising a polarizing film substrate, wherein the polarizing film substrate contains the azo compound according to any one of <1> to <10> or a salt thereof.

<12> A dye-based polarizing film comprising a polarizing film substrate, wherein the polarizing film substrate contains the azo compound according to any one of <1> to <10> or a salt thereof, and one of the other types The above organic dyes.

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

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

<15> A polarizing plate for liquid crystal display, which is a dye-based polarizing film according to any one of <11> to <13> or a dye-based polarizing plate such as <14>.

<16> A neutral gray polarizing plate for vehicle use, which is a dye-based polarizing film according to any one of <11> to <13>, a dye-based polarizing plate such as <14>, or a <15> A polarizing plate for liquid crystal display.

<17> A liquid crystal display device using a dye-based polarizing plate such as <14>, a polarizing plate for liquid crystal display such as <15>, or a neutral gray polarizing plate for automotive use as in <16>.

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

The azo compound of the present invention is represented by the above formula (1). A in the above formula (1) is a naphthyl group having a hydrogen atom, a hydroxyl group, an alkoxy group having a sulfonic acid group of 1 to 5 carbon atoms, and/or a sulfonic acid group, and at least one of R ₁ to R ₄ has a sulfonate. The acid group has an alkoxy group having 1 to 4 carbon atoms, and the other R ₁ to R ₄ groups 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.

Hereinafter, the compound of the formula (1) will be described. However, in the following substituents and the like, the carbon numbers 1 to 4 are referred to as "lower".

In the present case, the "substituent" contains a hydrogen atom, but is simply described as a "substituent".

A of the structure in the above formula (1) represents a naphthyl group having a substituent. The substituent is preferably a hydrogen atom, a sulfonic acid group, a hydroxyl group, a lower alkoxy group having a sulfonic acid group, or a sulfonic acid group. Preferably, A is a naphthyl group represented by the above formula (2), and R ₅ represents a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 5 carbon atoms having a sulfonic acid group, or a sulfonic acid group, and n is 1 to 3. Further, the position of the sulfo group may be on any of the benzene nuclei of the naphthalene ring. As the lower alkoxy group having a sulfonic acid group, a linear alkoxy group is preferred, and a substitution position of the sulfonic acid group is preferably at the alkoxy end. Preferred is 3-sulfonic acid propoxy group, 4-sulfonic acid butoxy group. The substitution position of the substituent which the naphthyl group has is not specifically limited. When the number is represented by the following formula (4), when the number of substituents is two, the combination of the 5-position and the 7-position, or the combination of the 6-position and the 8-position is preferable, and when the substituent is 3 Preferably, the 3-position and the 5-position and the 7-position, the 3-position and the 6-position and the 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, a lower alkoxy group, more preferably a hydrogen atom, a methyl group, an ethyl group, a methoxy group or an ethoxy group, particularly preferably a hydrogen atom, Base, ethyl, lower alkoxy group containing a sulfonic acid group. The lower alkoxy group having a sulfonic acid group in the above formula (1) is preferably a linear alkoxy group having a carbon number of 2 to 4, and the substitution position of the sulfonic acid group is at the terminal of the alkoxy group. More preferably, it is a 3-sulfonic acid propoxy group having a carbon number of 3 and a 4-sulfonic acid butoxy group having a carbon number of 4. Particularly preferred is a 3-sulfonylpropoxy group having a carbon number of 3.

The substitution position of R ₁ to R ₄ on the benzene ring is not particularly limited. If it is described by the following formula (5), it is preferably only 2-bit, only 5-position, a combination of 2-position and 6-position, a combination of 2-position and 5-position, and 3 - A combination of a bit and a 5-bit. More preferably, it is only a 2-bit, only a 5-bit, a 2-bit and a 5-bit combination. Further, in the above, only the 2-position and only the 5-position system represent a substituent having one hydrogen atom only in the 2-position or the 5-position. Particularly preferred is a combination of a 2-position 3-sulfonate propoxy group and a 5-position other substituent.

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

The azo compound or the salt thereof represented by the above formula (1) can be subjected to diazotization, coupling, and ureido group as described in Patent Document 3 by the method of producing the usual azo dye described in Non-Patent Document 1. It is easy to manufacture.

The specific manufacturing method is as follows.

By the same method as in Non-Patent Document 1, the following formula (i) The amine naphthalene (naphthylamine) having a substituent shown is diazotized to be coupled with an aniline of the following formula (ii) to obtain a monoazo represented by the following formula (iii). Amino compound.

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

(wherein R ₁ and R ₂ have the same meanings as those in the above formula (1).)

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

Next, the monoazoamine-based compound (iii) is diazotized and subjected to secondary coupling with an aniline of the following formula (iv) to obtain a disazo represented by the following formula (v). Amino compound.

(wherein R ₃ and R ₄ have the same meanings as those in the above formula (1).)

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

The azo compound of the above formula (1) is obtained by reacting the bisazoamine group compound (v) with a phenyl chloroformate.

In the above reaction, the diazotization step is carried out by mixing the nitrite of sodium nitrite or the like with an aqueous solution or suspension of a mineral acid such as hydrochloric acid or sulfuric acid of a diazo component, or by a diazonium component. The aqueous solution of the sexual or weakly basic is preliminarily added with nitrite, and the reverse method of mixing the mineral acid is carried out. The temperature of the diazotization is suitably -10 to 40 °C. Further, in the coupling step with the aniline, an acidic aqueous solution such as hydrochloric acid or acetic acid is mixed with the above respective diazonium liquids, and the acidic conditions are carried out at a temperature of -10 to 40 ° C at a pH of 2 to 7.

The monoazoamine-based compound and the bis-azo-amine-based compound obtained by coupling are taken out by filtration or precipitation by acid precipitation or salting out, or can be further carried out in the state of solution or suspension to the next step. . When the diazonium salt is poorly soluble and is a suspension, it can also be filtered and used as a press cake for the subsequent coupling step.

Used as a primary and secondary coupling with sulfonic acid The specific production method of the aniline of the alkoxy group (the above formula (ii) and/or (iv)) is carried out by sulfonic acid alkylation of the phenol according to the method shown on page 35 of Patent Document 4. And reduction to obtain a sulfonic acid alkoxyaniline, and can be used in a coupling step.

As a specific method for the urea group reaction of a bisazoamine-based compound and a phenyl chloroformate, as described in Patent Document 3, page 57, at a temperature of 10 to 90 ° C and a pH of 7 to 11 from neutral to It is carried out under alkaline conditions. After completion of the reaction, it was precipitated by salting out and filtered, and taken out. Further, if purification is required, salting out may be repeated or an organic solvent may be used to precipitate out of water. The organic solvent to be used for the purification may, for example, be a water-soluble organic solvent such as an alcohol such as methanol or ethanol or a ketone such as acetone.

Further, in the present invention, in addition to the use as the free acid, the azo compound represented by the above formula (1) can also be used as a salt of an azo compound. Examples of such a salt include organic salts such as a lithium salt, a sodium salt, and a potassium salt, and an organic salt such as an ammonium salt or an amine salt. The sodium salt is generally used.

The starting material for the water-soluble dye represented by the formula (1) is a naphthylamine having a hydrogen atom, a hydroxyl group, an alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms, or a sulfonic acid group: A-NH ₂ . A naphthylamine having a hydrogen atom, a hydroxyl group or a sulfonic acid group: as A-NH ₂ , for example, 4-aminonaphthalenesulfonic acid, 7-aminonaphthalene-3-sulfonic acid, 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-trisulphonic acid and the like. 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-trisulphonic acid Further, 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid, 1-aminonaphthalene-3,8-disulfonic acid or the like is preferred. When the compound represented by the formula (2) is synthesized, the naphthylamine having a sulfonic acid group and an alkoxy group having a sulfonic acid group having 1 to 5 carbon atoms may, for example, be 7-amino-3. -(3-sulfonatepropoxy)naphthalene-1-sulfonic acid, 7-amino-3-(4-sulfobutoxy)naphthalene-1-sulfonic acid, 7-amino-3-( 5-sulfonate pentyloxy)naphthalene-1-sulfonic acid, 7-amino-4-(3-sulfonylpropoxy)naphthalene-2-sulfonic acid, 7-amino-4-(4- Sulfobutyrate)naphthalene-2-sulfonic acid, 7-amino-4-(5-sulfonylpentyloxy)naphthalene-2-sulfonic acid, 6-amino-4-(3-sulfonic acid Propyloxy)naphthalene-2-sulfonic acid, 6-amino-4-(4-sulfobutoxy)naphthalene-2-sulfonic acid, 6-amino-4-(5-sulfonate pentane Oxy)naphthalene-2-sulfonic acid, 2-amino-5-(3-sulfonic acid propoxy)naphthalene-1,7-disulfonic acid, 6-amino-4-(3-sulfonic acid group Propoxy)naphthalene-2,7-disulfonic acid, 7-amino-3-(3-sulfopropoxy)naphthalene-1,5-disulfonic acid and the like.

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 or 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. A methyl group, an ethyl group, or a lower alkoxy group containing a sulfonic acid group.

The position of substitution of R ₁ to R ₄ in the aniline is not limited. Preferably, it is only 2-bit, only 5-bit, a combination of 2-bit and 6-bit, a combination of 2-bit and 5-position, a combination of 3-bit and 5-position, and the special series is only 2-bit, only 5-bit, a combination of 2-bit and 5-bit.

Examples of the aniline of the primary and/or secondary coupler include aniline, 2-methylaniline, 2-ethylaniline, 2-propylaniline, and 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 .

As another example of the aniline of the primary and/or secondary coupler, for example, 3-(2-amino-4-methylphenoxy)propane-1-sulfonic acid, 3-(2-amino group) 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-sulfonate , (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. Preferred is 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)B Alkyl-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 -sulfonic acid, especially 3-(2-amino-4-methylphenoxy)propane-1-sulfonic acid, 3-(2-amino-4-methylphenoxy)butane-1 - sulfonic acid.

These amine groups of anilines can also be protected. The protective group may, for example, be an ω-methane fluorenyl group.

Further, in the dye-based polarizing film or the dye-based polarizing plate of the present invention, the azo compound represented by the above formula (1) or a salt thereof may be used singly or in combination, and one or more other organic dyes may be used in combination as necessary. The organic dye to be combined is not particularly limited, and a dye having an absorption property in a wavelength region different from the absorption wavelength region of the azo compound of the present invention or a salt thereof is preferred, and a high dichroic property is 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 representative examples, and the use is as a patent for the purpose. The dyes developed by the polarizing plates as described in Documents 1 to 5 are preferred. These pigments are used as a salt of a free acid or an alkali metal salt (for example, a Na salt, a K salt, or a Li salt), an ammonium salt, or an amine.

When it is necessary to use other organic dyes in combination, the polarizing film for the purpose is a type of a polarizing film of a neutral color, a color polarizing film for a liquid crystal projector, or another color polarizing film, and the type of the dye to be used is different. The blending ratio is not particularly limited, but is generally 0.1 to 10 parts by mass based on the total mass of at least one of the organic dyes based on the mass of the azo compound of the above formula (1) or a salt thereof. It is preferred to use within the range.

If necessary, the azo compound represented by the above formula (1) or a salt thereof can be contained in a polarizing film substrate (for example, a polymer film) together with other dyes by a known method to align, or The liquid crystals are mixed together or aligned by a coating method to produce a polarizing film having various colors or neutral colors. The obtained polarizing plate is provided with a protective film, and is used as a polarizing plate, such as a protective layer, an AR (reflection preventing) layer, a support, etc., and is used for a liquid crystal projector, a computer, a clock, a notebook personal computer, a word processor, and the like. LCD TV, car navigation and indoor and outdoor A 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 a polyvinyl alcohol resin or a derivative thereof, and specific examples thereof include polyvinyl alcohol or a derivative thereof. And any one of these is obtained by denaturation of an olefin such as ethylene or propylene or an unsaturated carboxylic acid such as crotonic acid, acrylic acid, methacrylic acid or maleic acid. From the viewpoint of the adsorptivity and the alignment property of the dye, a film composed of polyvinyl alcohol or a derivative thereof is also suitably used. The thickness of the substrate is usually from 30 to 100 μm, preferably from 50 to 80 μm.

When such a polarizing film substrate (polymer film) contains the azo compound of the above formula (1) or a salt thereof, a method of dyeing a polymer film is usually employed. The dyeing is carried out, for example, by the following operations. First, the azo compound of the present invention or a salt thereof and, if necessary, a dye other than necessary are dissolved in water to prepare a dyebath. The concentration of the dye in the dyebath is not particularly limited and is usually selected from the range of 0.001 to 10% by mass. Further, a dyeing aid may be used as necessary. For example, it is suitable to use thenardite at a concentration of about 0.1 to 10% by mass. The polymer film was immersed in the dye bath prepared thereby 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 a salt thereof is carried out by stretching the polymer film dyed by the above operation. As a method of extending, any known method such as a wet method or a dry method can be used. The extension of the polymer film can also be carried out before dyeing, as the case may be. In this case, the alignment of the water-soluble dye is carried out at the time of dyeing. A polymer film containing a water-soluble dye and aligned is necessary by a known method It is treated after application of boric acid or the like. Such post-treatment is carried out for the purpose of improving the light transmittance and the degree of polarization of the polarizing film. The conditions of the boric acid treatment vary depending on the type of the polymer film to be used or the type of the dye to be used. However, the boric acid concentration of the boric acid aqueous solution is generally 0.1 to 15% by mass, preferably 1 to 10% by mass, and is preferably treated. It is carried out by immersing in a temperature range of 30 to 80 ° C, preferably 40 to 75 ° C for 0.5 to 10 minutes. Further, if necessary, an aqueous solution containing a cationic polymer compound may be used together for a fix treatment.

The dye-based polarizing film of the present invention thus obtained is obtained by laminating a transparent protective film having excellent optical transparency and mechanical strength on one surface or both surfaces thereof to form a polarizing plate. As the material for forming the protective film, for example, a cellulose acetate film or an acrylic film may be used, and a fluorine film such as a tetrafluoroethylene/hexafluoropropylene copolymer, a polyester resin, or a polyolefin may be used. A film made of a resin or a polyamide resin. A triethylenesulfonyl cellulose (TAC) film or a cycloolefin film is preferably used. The thickness of the protective film is usually 40 to 200 μm.

Examples of the adhesive which can be used for bonding the polarizing film and the protective film include a polyvinyl alcohol-based adhesive, a urethane emulsion-based adhesive, an acrylic adhesive, and a polyester-isocyanate adhesive. Suitable as a polyvinyl alcohol-based adhesive.

Further, a transparent protective layer may be further provided on the surface of the dye-based polarizing plate of the present invention. Examples of the protective layer include a hard coat layer of an acrylic or polyoxyalkylene system, a protective layer of an urethane type, and the like. Moreover, in order to further improve the light transmittance of the single board, the AR layer is disposed on the protective layer. good. The AR layer can be formed by, for example, vapor deposition or sputtering treatment of a substance such as cerium oxide or titanium oxide, and can be formed by coating a fine fluorine-based substance. Further, the dye-based polarizing plate of the present invention can also be used as an elliptically polarizing plate to which a phase difference plate has been attached.

The dye-based polarizing plate of the present invention thus constituted is characterized in that it has a neutral color, has no orthogonal color leakage in a wavelength region of a visible light region, and has excellent polarizing performance even under high temperature and high humidity conditions. Without causing discoloration or a decrease in polarizing performance, light leakage under the orthogonal position in the visible light region is small.

The neutral gray polarizing plate for vehicle-mounted use of the present invention contains the azo compound represented by the above formula (1) or a salt thereof, and further contains the other organic dye as a dichroic dye as necessary. Further, the polarizing film used in the color polarizing plate for a liquid crystal projector of the present invention can also be produced by the above-described manufacturing method. Further, a polarizing plate is added to the protective film, and a protective layer, an AR layer, a support, and the like are provided as necessary, and a neutral gray polarizing plate for use in a vehicle is used.

As a color polarizing plate for liquid crystal projectors, the necessary wavelength range of the polarizing plate (A. When using an ultrahigh pressure mercury lamp; 420 to 500 nm for blue channel, 500 to 580 nm for green channel, 600 to 680 nm for red channel, B. 3 primary colors) The peak wavelength of the LED lamp; the average light transmittance of the single plate in the blue channel is 430~450nm, the green channel is 520~535nm, and the red channel is 620~635nm), and the average light transmittance of the orthogonal bit is 0.4. % or less, preferably, the average light transmittance of the single plate in the necessary wavelength range of the polarizing plate is 41% or more, and the average light transmittance of the orthogonal position is 0.3%. Hereinafter, it is preferably 0.2% or less. 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 dots is 0.1% or less. The color polarizing plate for a liquid crystal projector of the present invention has brightness and excellent polarizing performance as described above.

In addition, the average light transmittance of the veneer is a specific wavelength region when natural light is incident on one of the polarizers which are not provided with the AR layer and the transparent glass plate (the following is the same meaning when used simply as a polarizing plate). The average value of the light transmittance. The average light transmittance of the orthogonal bits is an average value of light transmittance in a specific wavelength region when natural light is incident on two polarizing plates in which the alignment directions are arranged in orthogonal positions.

The neutral gray polarizing plate for vehicle-mounted use of the present invention is preferably a polarizing plate having an AR layer provided on a polarizing plate comprising a polarizing film and a protective film, and is attached to a transparent resin or the like. A polarizing plate with an AR layer and a support on the support is preferred.

The neutral gray polarizing plate for vehicle use of the present invention is generally used as a polarizing plate with a support. Since the support is attached with a polarizing plate, it is preferable to have a flat portion, and since it is used for optical purposes, a transparent substrate is preferred. The transparent substrate is roughly classified into an inorganic substrate and an organic substrate, and examples thereof include an inorganic substrate such as soda glass, borosilicate glass, a crystal substrate, a sapphire substrate, or a spinel substrate, or acrylic, polycarbonate, or polypyrene. An organic substrate such as ethylene glycol diester, polyethylene naphthalate or a cycloolefin polymer, but an organic substrate is preferred. The thickness or size of the transparent substrate can be the desired size. Moreover, in order to increase the light transmittance of the single plate, the polarizing plate with the transparent substrate is provided on one or both sides of the supporting body surface or the polarizing plate surface. The AR layer is better.

In the case of producing a color polarizing plate with a support for vehicle use, for example, a transparent adhesive (adhesive) agent is applied to the flat surface of the support, and then the dye-based polarizing plate of the present invention may be attached to the coated surface. Further, a transparent adhesive (adhesive) may be applied to the polarizing plate, and then the support may be attached to the coated surface. The adhesive (adhesive) used herein is preferably, for example, an acrylate. When the polarizing plate is used as an elliptically polarizing plate, the phase difference plate side is usually attached to the support side, but the polarizing plate side may be attached to the transparent substrate.

In other words, in the liquid crystal display for vehicle use using the dye-based polarizing plate of the present invention, the dye-based polarizing plate of the present invention is disposed on either or both of the incident side and the exit side of the liquid crystal cell. The polarizing plate may or may not be in contact with the liquid crystal cell, but it is preferably not contacted from the viewpoint of durability. On the exit side, when the polarizing plate is in contact with the liquid crystal cell, 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 preferable to use the dye-based polarizing plate of the present invention using a support other than the liquid crystal cell. Moreover, it is preferable 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 from the viewpoint of durability, 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 preferable to arrange the support body surface on the light source side. Further, the incident side of the liquid crystal cell refers to the light source side, and the opposite side is referred to as the exit side.

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

The neutral gray polarizing plate for vehicle-mounted use is characterized in that it has excellent polarizing performance and does not cause discoloration or a decrease in polarizing performance even in a high-temperature, high-humidity state in a vehicle.

[Examples]

In the following, the present invention will be described in more detail by way of examples, but these are not to be construed as limiting. The % and parts in the examples are quality benchmarks unless otherwise defined.

(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 was added, followed by 6.9 parts of sodium nitrite, and stirred for 1 hour. 24.5 parts of 3-(2-amino-4-methylphenoxy)propane-1-sulfonic acid dissolved in water was added thereto, and stirred at 30 to 40 ° C while adding sodium carbonate to prepare pH 5, and then After stirring, the coupling reaction was completed, and 50.4 parts of the monoazoamine group 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 thereto, and then 6.2 parts of sodium nitrite was added thereto, and the mixture was stirred at 25 to 30 ° C for 2 hours to carry out diazotization. To this, 22 parts of 3-(2-amino-4-methylphenoxy)propane-1-sulfonic acid dissolved in water was added, and the mixture was stirred at 30 to 40 ° C while adding sodium carbonate to prepare pH 5, and then After stirring, the coupling reaction was completed, and 65.3 parts of the bisazoamine group compound represented by the following formula (80) was obtained.

65.3 parts of the obtained bisazoamine-based compound was added to 250 parts of water, and dissolved with sodium hydroxide, and 6.2 parts of phenyl chloroformate was stirred at 30 to 70 ° C for 2 hours to carry out urea-formation. Salting out with sodium chloride and filtering to obtain 41.4 parts of the azo compound of the present invention represented by the above formula (6). The maximum absorption wavelength in this 20% aqueous pyridine solution of this compound was 486 nm.

(Example 2)

The same procedure as in Example 1 was carried out except that 7-aminonaphthalene-1,3-disulfonic acid was changed to 30.3 parts of 6-aminonaphthalene-1,3-disulfonic acid in Example 1. (7) 41.4 parts of the azo compound of the present invention shown. The maximum absorption wavelength in this 20% aqueous pyridine solution of this compound was 480 nm.

(Example 3)

The same procedure as in Example 1 was carried out except that 7-aminonaphthalene-1,3-disulfonic acid was changed to 30.3 parts of 7-aminonaphthalene-1,5-disulfonic acid in Example 1. (8) 41.4 parts of the azo compound of the present invention shown. The maximum absorption wavelength in the 20% aqueous pyridine solution of this compound was 523 nm.

(Example 4)

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

(Example 5)

In the same manner as in the first-time coupling of the above-mentioned Example 1, 50.4 parts of the monoazoamine-based compound represented by the above formula (79) 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 the addition of sodium nitrite 6.2 parts were stirred at 25 to 30 ° C for 2 hours for diazotization. To this, 10.9 parts of 2,5-dimethylaniline was added, and the mixture was stirred at 30 to 40 ° C, and sodium carbonate was added thereto to prepare pH 3, followed by stirring to complete the coupling reaction, and the following formula (81) was obtained. The bisazoamine based compound was 55.3 parts.

55.3 parts of the obtained bisazoamine-based compound was added to 250 parts of water, and dissolved with sodium hydroxide, and 6.2 parts of phenyl chloroformate was stirred at 30 to 70 ° C for 2 hours to carry out urea-formation. Salting out with sodium chloride and filtering 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 a 20% aqueous pyridine solution was 455 nm.

(Example 6)

The azo compound of the present invention represented by the above formula (31) was obtained in the same manner as in Example 5 except that 2,5-dimethylaniline was changed to 9.8 parts of 2-methoxyaniline in Example 5. 35.3 servings. The maximum absorption wavelength in this 20% aqueous pyridine solution of this compound was 480 nm.

(Example 7)

In addition to the modification of 7-aminonaphthalene-1,3-disulfonic acid to 6-amine in Example 5 30.3 parts of naphthalene-1,3-disulfonic acid, and the same procedure as in Example 5 was carried out except that 2,5-dimethylaniline was changed to 3-methylaniline, and the formula (32) was obtained. The azo compound of the invention was 34.5 parts. The maximum absorption wavelength in the 20% aqueous pyridine solution of this compound was 452 nm.

(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 was added, followed by 6.9 parts of sodium nitrite, and stirred for 1 hour. To this, 12.1 parts of 2,5-dimethylaniline was added, and the mixture was stirred at 30 to 40 ° C, and sodium carbonate was added thereto to prepare pH 5, followed by stirring to complete the coupling reaction, and a single sample represented by the following formula (82) was obtained. The azoamine compound was 39.2 parts.

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 to 30 ° C for 2 hours to carry out diazotization. To this, 19.6 parts of 3-(2-amino-4-methylphenoxy)propane-1-sulfonic acid was added, and stirring was carried out at 30 to 40 ° C while adding sodium carbonate to prepare pH 5, followed by stirring to effect coupling reaction. After completion, 55.3 parts of the bisazoamine group compound represented by the following formula (83) was obtained.

55.3 parts of the obtained bisazoamine-based compound was added to 250 parts of water, and dissolved with sodium hydroxide, and 6.2 parts of phenyl chloroformate was stirred at 30 to 70 ° C for 2 hours to carry out urea-formation. Salting out with sodium chloride and filtering 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 a 20% aqueous pyridine solution was 463 nm.

(Example 9)

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

(Embodiment 10)

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

(Example 11)

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

(Embodiment 12)

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

(Example 13)

The same procedure as in Example 8 was carried out except that 7-aminonaphthalene-1,3-disulfonic acid was changed to 6-aminonaphthalene-1,3-disulfonic acid in Example 8, and the above formula (57) was obtained. ) 35.2 parts of the azo compound of the present invention shown. The maximum absorption wavelength of this compound in a 20% aqueous pyridine solution was 453 nm.

(Example 14)

The present invention of the above formula (58) was obtained in the same manner as in Example 8 except that 2,5-dimethylaniline was changed to 2-methoxy-5-methylaniline in Example 8. The azo compound was 36.8 parts. The maximum absorption wavelength of this compound in a 20% aqueous pyridine solution was 487 nm.

(Example 15)

A polyvinyl alcohol having a thickness of 75 μm was immersed in an aqueous solution of 0.03% of the compound of the above formula (6) obtained in Example 1 and a concentration of 0.1% of sodium sulfate for 4 minutes. This film was extended to 5 times in a 3% boric acid aqueous solution at 50 ° C, and washed with water and dried under tension to obtain a polarizing film of the present invention.

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

(Embodiment 16)

A polyvinyl alcohol having 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 a concentration of 0.1% of sodium sulfate for 4 minutes. This film was extended to 5 times in a 3% boric acid aqueous solution at 50 ° C, and washed with water and dried under tension to obtain a polarizing film of the present invention.

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

(Example 17)

A polyvinyl alcohol having a thickness of 75 μm was immersed in an aqueous solution of 0.03% of the compound of the above formula (52) obtained in Example 8 and a concentration of 0.1% of sodium sulfate for 4 minutes. This film was extended to 5 times in a 3% boric acid aqueous solution at 50 ° C, and washed with water and dried under tension to obtain a polarizing film of the present invention.

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

Further, the test methods are described below.

The measurement of the maximum absorption wavelength of the polarizing film and the calculation of the polarization ratio were carried out by using a spectrophotometer (U-4100 manufactured by Hitachi, Ltd.) to measure the parallel transmittance at the time of incident polarized light and the orthogonal transmittance.

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

The parallel transmittance and the orthogonal transmittance of each wavelength were measured at intervals of 1 nm at 380 to 780 nm. Using the values of the individual measurements, the polarization ratio of each wavelength was calculated by the following formula (i), and the polarizing ratio at the highest at 380 to 780 nm and its maximum absorption wavelength (nm) were obtained.

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

(Examples 18 to 20)

The azo compound (the compound of the above formulas (7) to (9)) described in Examples 2 to 4 was used instead of the compound of the above formula (6), and the polarizing of the present invention was carried out in the same manner as in Example 15. membrane. The maximum absorption wavelength and polarization ratio of the obtained polarizing film are shown in Table 1.

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

(Examples 21 and 22)

The polarizing film of the present invention was obtained in the same manner as in Example 16 except that the azo compounds (the compounds of the above formulas (31) and (32)) described in Examples 6 and 7 were used instead of the above formula (30). The maximum absorption wavelength and polarization ratio of the obtained polarizing film are shown in Table 1.

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

(Examples 23 to 28)

The azo compound (the compound of the above formula (53) to (58)) described in Examples 9 to 14 was used instead of the compound of the above formula (52), and the polarizing of the present invention was obtained in the same manner as in Example 17 except that the polarizing of the present invention was carried out. membrane. The maximum absorption wavelength and polarization ratio of the obtained polarizing film are shown in Table 1.

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

(test example)

As an indicator of image quality, there is a contrast between the white display and the black display, and the polarizing film obtained in Examples 15 and 18-20; 16, 21 and 22; and 17 and 23-28 The maximum absorption wavelength and comparison at this time are shown in Table 2. In this comparison, the parallel transmission The ratio of the ratio to the orthogonal transmittance (contrast = parallel transmittance at the maximum absorption wavelength (Ky) / straight transmittance at the maximum absorption wavelength (Kz)), the larger the value, the more excellent the polarization performance of the polarizing plate. Further, the evaluation of the polarizing performance was performed by comparing the parallel transmittances of the maximum absorption wavelengths of the polarizing films. As shown in Table 2, the polarizing films made using these compounds have high contrast.

(Comparative Example 1)

In place of the compound of the present invention, the compound (4) of Patent Document 4 synthesized in the same manner as the method described in Example 2 of Patent Document 4 was used, and a polarizing film was produced in the same manner as in Example 15 of the present invention. Calculate the comparison. As shown in Table 2, the compounds of the present invention exhibited high contrast and excellent polarizing performance with respect to Comparative Example 1.

(Comparative Example 2)

In place of the compound of the present invention, the compound (I-3) synthesized in the same manner as in the method of [0077] in Patent Document 5 was used, and a polarizing film was produced in the same manner as in Example 15 of the present invention, and the comparison was calculated. As shown in Table 2, the compounds of the present invention exhibited high contrast and excellent polarizing performance with respect to Comparative Example 2.

(Example 29)

The same operation as in Example 15 except that the compound (6) obtained in Example 1 was used as an aqueous solution of a dye of 0.2%, CI Direct Orange 39 0.07%, CI Direct Blue 274 0.02%, and Glauber's nitrate 0.1% concentration. And made a polarizing film. The maximum absorption wavelength of the obtained polarizing film is At 576 nm, the average transmittance of a single plate at 380 to 600 nm is 42%, the average light transmittance at orthogonal positions is 0.02%, and it has a high degree of polarization.

A triethylenesulfonated cellulose film (TAC film; manufactured by Fujifilm Co., Ltd.; trade name: TD-80U) was laminated on both surfaces of the polarizing film via an adhesive of a polyvinyl alcohol aqueous solution, and an AR support was obtained using an adhesive. The dye of the present invention is a polarizing plate (neutral gray polarizing plate). The polarizing plate of the present invention has a high polarizing ratio and exhibits long-term durability even in a state of high temperature and high humidity. It is also excellent for long-term exposure to light.

(Embodiment 30)

The same operation as in Example 16 was carried out except that the compound (30) obtained in Example 5 was used as an aqueous solution of a dye of 0.2%, CI Direct Orange 39 0.07%, CI Direct Blue 274 0.02%, and Glauber's nitrate 0.1% concentration. And made a polarizing film. The obtained polarizing film has a maximum absorption wavelength of 577 nm, an average transmittance of a single plate at 380 to 600 nm of 42%, an average light transmittance of 0.02% in an orthogonal position, and a high degree of polarization.

A triethylenesulfonated cellulose film (TAC film; manufactured by Fujifilm Co., Ltd.; trade name: TD-80U) was laminated on both surfaces of the polarizing film via an adhesive of a polyvinyl alcohol aqueous solution, and an AR support was obtained using an adhesive. The dye of the present invention is a polarizing plate (neutral gray polarizing plate). The polarizing plate of the present invention has a high polarizing ratio and exhibits long-term durability even in a state of high temperature and high humidity. It is also excellent for long-term exposure to light.

Example 31

The same operation as in Example 17 was carried out except that the compound (52) obtained in Example 8 was used as an aqueous solution of a dye of 0.2%, CI Direct Orange 39 0.07%, CI Direct Blue 274 0.02%, and Glauber's nitrate 0.1% concentration. And made a polarizing film. The obtained polarizing film has a maximum absorption wavelength of 575 nm, a single plate average transmittance of 42% at 380 to 600 nm, an average light transmittance of 0.02% in the orthogonal position, and a high degree of polarization.

A triethylenesulfonated cellulose film (TAC film; manufactured by Fujifilm Co., Ltd.; trade name: TD-80U) was laminated on both surfaces of the polarizing film via an adhesive of a polyvinyl alcohol aqueous solution, and an AR support was obtained using an adhesive. The dye of the present invention is a polarizing plate (neutral gray polarizing plate). The polarizing plate of the present invention has a high polarizing ratio and exhibits long-term durability even in a state of high temperature and high humidity. It is also excellent for long-term exposure to light.

Claims (17)

An azo compound represented by the following formula (1) or a salt thereof; In the formula, A is a naphthyl group having a hydrogen atom, a hydroxyl group, an alkoxy group having a sulfonic acid group having 1 to 5 carbon atoms, and/or a sulfonic acid group, and at least one of R ₁ to R ₄ is independently a sulfonic acid group. The alkoxy group having a carbon number of 1 to 4, and the other R ₁ to R ₄ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. The azo compound of the claim 1 or a salt thereof, wherein the other R ₁ to R ₄ are each independently a hydrogen atom, a methyl group or a methoxy group, in the above formula (1). The azo compound or a salt thereof according to claim 1 or 2, wherein (a) R ₁ is an alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms, and (b) R ₃ is a carbon number having a sulfonic acid group; The alkoxy group of ~4, or (c) R ₁ and R ₃ are each independently an alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms. The azo compound or a salt thereof according to any one of claims 1 to 3, wherein the lower alkoxy group having a sulfonic acid group is a 3-sulfonic acid propoxy group in the above formula (1). The azo compound or a salt thereof according to any one of claims 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 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 a salt thereof; R ₆ is a hydrogen atom, a hydroxyl group, and/or an alkoxy group having a sulfonic acid group having 1 to 5 carbon atoms, and at least one of R ₇ to R ₁₀ is an alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms. The other R ₇ to R ₁₀ groups are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and x is an integer of 1 to 3. The azo compound of the above-mentioned formula (3), wherein R ₇ to R _{10 which} are not alkoxy groups having 1 to 4 carbon atoms having a sulfonic acid group are each independently a hydrogen atom, Methyl, methoxy. The azo compound or a salt thereof according to claim 6 or 7, wherein (a) R ₈ is an alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms, and (b) R ₁₀ is a carbon number having a sulfonic acid group; The alkoxy group of ~4, or (c) R ₈ and R ₁₀ are each independently an alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms. The azo compound or a salt thereof according to any one of claims 6 to 8, wherein R ₆ is a hydrogen atom and x is 2 in the above formula (3). The azo compound or a salt thereof according to any one of claims 6 to 9, wherein the alkoxy group having a sulfonic acid group having 1 to 4 carbon atoms is 3 in the above formula (3) Sulfopropyl propoxy. A dye-based polarizing film comprising a polarizing film substrate, wherein the polarizing film substrate contains the azo compound according to any one of claims 1 to 10 or a salt thereof. A dye-based polarizing film comprising a polarizing film substrate, wherein the polarizing film substrate contains the azo compound according to any one of claims 1 to 10 or a salt thereof, and one or more organic dyes other than the above. The dye-based polarizing film according to claim 11 or 12, wherein the polarizing film substrate is a film composed of a polyvinyl alcohol resin or a derivative thereof. A dye-based polarizing plate which can be obtained by laminating a transparent protective layer on at least one surface of the dye-based polarizing film according to 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 neutral gray polarizing plate for use in a vehicle, which is a dye-based polarizing film according to any one of claims 11 to 13, a dye-based polarizing plate according to claim 14, or a polarizing plate for liquid crystal display according to claim 15 . A liquid crystal display device using the dye-based polarizing plate of claim 14, the polarizing plate for liquid crystal display of claim 15, or the neutral gray polarizing plate for automotive use according to claim 16.