KR20180006926A - Azo compounds, dye-based polarizing film containing same, and polarizing plate - Google Patents

Abstract

An object of the present invention is to provide an azo compound useful as a dichroic dye for use in a polarizing plate having excellent polarizing performance and durability and having little color leakage in a visible light region and a neutral gray polarizing plate for use in a vehicle using the same. (1) wherein A is a naphthyl group having a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 5 carbon atoms and a sulfo group and / or a sulfo group, at least one of R ₁ to R ₄ is An alkoxy group having 1 to 4 carbon atoms and a sulfo group, 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.

Description

AZO COMPOUNDS, DYE-BASED POLARIZING FILM CONTAINING SAME, AND POLARIZING PLATE <br> <br> <br> Patents - stay tuned to the technology AZO COMPOUNDS, DYE-BASED POLARIZING FILM CONTAINING 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 transmission / 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. Examples of application areas of this LCD include notebook PCs, word processors, liquid crystal projectors, liquid crystal televisions, car navigation systems, and indoor and outdoor measurement instruments from small electronic devices such as electronic desk calculators and watches at the early stage. Further, the present invention can be applied to a lens having a polarizing function, and has been applied to sunglasses having improved visibility and polarizing glasses corresponding to 3D TVs and the like. Since the use of the polarizing plate as described above is widespread, the polarizing plate having high polarization performance and high durability is required because the use conditions are also used under a wide range of conditions from low temperature to high temperature, low humidity to high humidity, and low light quantity to high light quantity have.

Presently, the polarizing plate is a polarizing film substrate such as a film of polyvinyl alcohol or derivative thereof in stretched orientation or a degenerated acid of polyvinyl chloride film or a polyene film produced by orienting a polyene produced by dehydration of polyvinyl alcohol film, Iodine or a dichroic dye. These are substances which greatly affect the polarization characteristics and durability of the polarizing plate. The iodine polarizing film using iodine is excellent in the polarization performance but weak in water and heat and has a problem in its durability when it is used for a long time in a state of high temperature and high humidity. A method in which an aqueous solution containing formaldehyde or boric acid is used to improve durability or a method in which a polymer film having a low moisture permeability is used as a protective film can be considered, but the effect is not sufficient. On the other hand, the dye-based polarizing film using a dye is superior in moisture resistance and heat resistance to an iodine polarizing film, but generally has insufficient polarization performance.

Until recently, images were displayed at a high luminance to enhance the sharpness of the image of the liquid crystal display. In a hybrid car or a mobile terminal equipped with such a display, there has been a demand to increase the driving time of a battery. Therefore, a liquid crystal display maker has a polarizer capable of maintaining the brightness and color of the image, .

However, when a polarizing film formed by adsorbing and orienting various kinds of dyes on a polymer film has light leakage (color leakage) at a specific wavelength in a wavelength region of the visible light region, when the polarizing film is attached to the liquid crystal panel, The color of the liquid crystal display may change. In order to prevent discoloration of the liquid crystal display due to color leakage at a specific wavelength in the dark state when the polarizing film is attached to the liquid crystal display device, it is necessary to use a polarizing film having a neutral color, , So that the transmittance (orthogonal transmittance) at the orthogonal position in the wavelength region of the visible light region must be made low evenly. In addition, in the on-vehicle liquid crystal display, a polarizing plate free from a change in polarization degree is required because it becomes a high temperature and high humidity environment in summer cars. Previously, an iodine-based polarizer that exhibits good polarizing performance and exhibits neutral gray has been used. However, the iodine-based polarizer has a problem that the light resistance, the heat resistance and the moisture resistance are insufficient as described above. To solve this problem, a dye-based neutral gray polarizing plate having various dyes or containing dichroic dyes has been used. The dye-based neutral gray polarizer generally uses a combination of red, blue, and yellow dyes, which are three primary colors of light. However, as described above, the polarizing performance of the dye-based neutral gray polarizer is not sufficient. Therefore, development of dichroic dyes having good polarization performance for each of the three primary colors was required.

The dye system is characterized by dyeing or containing respective independent dyes corresponding thereto in order to control the components of the three primary colors of light as described above. The light source used in recent liquid crystal display panels is a cold cathode tube type or an LED type, but the wavelength of a light source emitted from the light source differs depending on the system. Even in the same system, there are many cases depending on each panel manufacture. Therefore, in developing a dichroic dye having good polarization performance, it is particularly important to design a dichroic dye having an absorption wavelength that matches the wavelength of the light source.

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

Japanese Patent No. 2622748 Japanese Laid-Open Patent Publication No. 2001-33627 Japanese Laid-Open Patent Publication No. 2009-132794 Japanese Patent No. 4270486 Japanese Patent No. 4360100

 Dye chemistry; Hosoda Yutaka, published by Jikdo (technical journal), 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. Another object of the present invention is to provide a polarizing plate exhibiting a neutral gray formed by adsorbing and orienting two or more kinds of dichroic dyes on a polymer film and having excellent coloring performance without any color leakage on the orthogonal region in the wavelength region of the visible light region, And a high performance polarizer having moisture resistance, heat resistance and light resistance.

A further object of the present invention is to provide a polarizing plate which is a dye-based neutral gray polarizing plate for on-vehicle liquid crystal displays and which has high brightness and good polarization performance, durability and light resistance.

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted intensive studies in order to achieve these objects, and as a result, they have found that a polarizing film and a polarizing plate containing a specific azo compound or a salt thereof have excellent polarization performance, moisture resistance, heat resistance and light resistance, Respectively.

That is, the present invention relates to:

(1)

[Chemical Formula 1]

(Wherein A is a naphthyl group having a hydrogen atom, a hydroxyl group, a sulfo group, and an alkoxy group having 1 to 5 carbon atoms and / or a sulfo group, and at least one of R ₁ to R ₄ is independently a sulfo group 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)

Or a salt thereof,

&Lt; 2 &

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

&Lt; 3 &

(a) R ₁ is alkyl group which has a sulfo group an alkoxy group of 1 to 4, (b) R ₃ is having a sulfo group an alkoxy group having from 1 to 4 carbon atoms, or (c) R ₁ and R ₃ are each independently an alcohol The azo compound or a salt thereof according to < 1 > or < 2 &gt;, which is an alkoxy group having 1 to 4 carbon atoms,

&Lt; 4 &

The azo compound or a salt thereof according to any one of <1> to <3>, wherein the lower alkoxy group having a sulfo group is a 3-sulfoproxy group in the formula (1)

&Lt; 5 &

A is represented by the following formula (2)

(2)

(Wherein R ₅ is a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 5 carbon atoms having a sulfo group, or a sulfo group, and n is an integer of 1 to 3)

, An azo compound or a salt thereof according to any one of < 1 > to < 4 &

&Lt; 6 &

(3)

(3)

(Wherein R ₆ is a hydrogen atom, a hydroxyl group, and / or an alkoxy group having 1 to 5 carbon atoms having a sulfo group, at least one of R ₇ to R ₁₀ is an alkoxy group having 1 to 4 carbon atoms, Each of R ₇ to R ₁₀ independently represents 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)

An azo compound or a salt thereof,

&Lt; 7 &

The azo compound or a salt thereof according to <6>, wherein R ₇ to R _10, which are not alkoxy groups having 1 to 4 carbon atoms and having a sulfo group, are each independently a hydrogen atom, a methyl group or a methoxy group,

&Lt; 8 &

(a) R ₈ is an alkoxy group having 1 to 4 carbon atoms having a sulfo group, (b) R ₁₀ is an alkoxy group having 1 to 4 carbon atoms having a sulfo group, or (c) R ₈ and R ₁₀ each independently An azo compound or a salt thereof according to < 6 > or < 7 &gt;, which is an alkoxy group having 1 to 4 carbon atoms,

&Lt; 9 &

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 formula (3)

&Lt; 10 &

The azo compound or a salt thereof according to any one of < 6 > to < 9 >, wherein the alkoxy group having 1 to 4 carbon atoms having a sulfo group is a 3-sulfoproxy group,

&Lt; 11 &

A polarizing plate comprising a polarizing film substrate containing an azo compound or salt thereof according to any one of < 1 > to < 10 >

&Lt; 12 &

A polarizing film substrate comprising at least one azo compound or salt thereof according to any one of < 1 > to < 10 >, and at least one organic dye other than these,

&Lt; 13 &

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

&Lt; 14 &

A dye-based polarizing plate capable of being obtained by bonding a transparent protective layer to at least one surface of the dye-based polarizing film described in any one of < 11 > to < 13 &

<15>

Based polarizing film described in any one of < 11 > to < 13 >, or a dye-based polarizing plate described in &

&Lt; 16 &

A neutral gray polarizing plate for on-vehicle use, which uses the dye-based polarizing film according to any one of <11> to <13>, the dye-based polarizing plate described in <14>, or the polarizing plate for liquid crystal display described in <

&Lt; 17 &

A liquid crystal display device using the dye-based polarizing plate described in <14>, the polarizing plate for liquid crystal display described in <15>, or the neutral gray polarizing plate for vehicle use described in <

.

The azo compound or its salt of the present invention is useful as a dye for a polarizing film. The polarizing film containing these compounds has a high polarization performance comparable to a polarizing film using iodine and has excellent durability. Therefore, it is preferable for various liquid crystal displays and liquid crystal projectors, for use in automobiles requiring high polarization performance and durability, and for display of industrial instruments used in various environments.

The azo compound of the present invention is represented by the above formula (1). In the formula (1), A is a naphthyl group having a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 5 carbon atoms having a sulfo group and / or a sulfo group, and at least one of R ₁ to R ₄ is a sulf 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.

Hereinafter, the compound of formula (1) will be described, but in the following substituents and the like, 1 to 4 carbon atoms are referred to as &quot; lower &quot;.

In the present invention, the "substituent" includes a hydrogen atom, but is described as a "substituent" for convenience.

A in the above formula (1) represents a naphthyl group having a substituent. The substituent is preferably a hydrogen atom, a sulfo group, a hydroxyl group, a lower alkoxy group having a sulfo group or a sulfo group. More preferably, A is a naphthyl group represented by the formula (2), R ₅ is a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 5 carbon atoms having a sulfo group, or a sulfo group, 3. The position of the sulfone group may be located in any benzene nucleus of the naphthalene ring. As the lower alkoxy group having a sulfo group, a linear alkoxy group is preferable, and a substitution position of a sulfo group is preferably an alkoxy group terminal. More preferred is a 3-sulfoproxy group or a 4-sulfobutoxy group. The substitution position of the substituent of the naphthyl group is not particularly limited. In the case of two substituents, the combination of the 5-position and the 7-position or the combination of the 6-position and the 8-position is preferable. When the substituent is 3, 5-position and 7-position, 3-position, 6-position and 8-position are preferred.

[Chemical Formula 4]

In the formula (1), R ₁ to R ₄ may have a substituent, and the substituent is not limited. Preferably, each of R ₁ to R ₄ independently represents a hydrogen atom, a lower alkyl group or a lower alkoxy group, more preferably a hydrogen atom, a methyl group, an ethyl group, a methoxy group or an ethoxy group, , A methyl group, an ethyl group, and a lower alkoxy group having a sulfo group. The lower alkoxy group having a sulfo group in the above formula (1) is preferably straight chain alkoxy having 2 to 4 carbon atoms, and the substitution position of the sulfo group is the terminal of the alkoxy group. More preferably a 3-sulfoprothoxy group having 3 carbon atoms and a 4-sulfobutoxy group having 4 carbon atoms. Especially preferred is a 3-sulfoproxy group having 3 carbon atoms.

The substitution position of R ₁ to R _{4 in} the benzene ring is not particularly limited. Position, only the 5-position, the combination of the 2-position and the 6-position, the combination of the 2-position and the 5-position, It is a combination of 5-position. More preferably, it is a 2-position only, a 5-position only, a 2-position and a 5-position combination. In addition, in the above, only the 2-position and the 5-position only mean that there is one substituent other than a hydrogen atom in the 2-position or the 5-position. Especially preferred is a combination of a 3-sulfoproxide group at the 2-position and other substituents at the 5-position.

[Chemical Formula 5]

Specific examples of the azo compound represented by the above formula (1) used in the present invention are shown below. In addition, the sulfo group, carboxyl group and hydroxyl group in the formula are expressed in the form of free acid.

[Chemical Formula 6]

(7)

[Chemical Formula 8]

[Chemical Formula 9]

[Chemical formula 10]

(11)

[Chemical Formula 12]

[Chemical Formula 13]

[Chemical Formula 14]

The azo compound represented by the formula (1) or a salt thereof may be subjected to diazotization, coupling, or ureidoation as described in Patent Document 3 in accordance with a conventional method of producing an azo dye as described in Non-Patent Document 1 Can be easily produced.

Specific production methods are shown below.

The aminaphthalene (naphthylamine) having a substituent as shown in the following formula (i) is diazotized by the same method as in the non-patent document 1 and is coupled with an aniline of the following formula (ii) to obtain a monoazoamino compound represented by the formula (iii).

[Chemical Formula 15]

(Wherein A represents the same meaning as in the above formula (1)).

[Chemical Formula 16]

(Wherein R ₁ and R ₂ have the same meanings as in the above formula (1)),

[Chemical Formula 17]

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

Subsequently, the monoazoamino compound (iii) is diazotized and subjected to secondary coupling with an aniline of the following formula (iv) to obtain a disazoamino compound represented by the following formula (v).

[Chemical Formula 18]

(Wherein R ₃ and R ₄ have the same meanings as in the above formula (1)),

[Chemical Formula 19]

(Wherein A and R ₁ to R ₄ have the same meanings as in the above formula (1)),

The azo compound of the formula (1) is obtained by reacting the disazo amino compound (v) with phenyl chloroformate.

In the above reaction, the diazotization step may be carried out in accordance with a compliant method in which a diacid component hydrochloric acid, an aqueous solution or suspension of a mineral acid such as sulfuric acid, or the like is mixed with a nitrite such as sodium nitrite, or a nitrite solution is added to a neutral or weakly alkaline aqueous solution , And mixing it with the mine is carried out by a reciprocal method (inverse method). The diazotization temperature is suitably from -10 to 40 占 폚. The coupling step with anilines is carried out under acidic conditions at a temperature of -10 to 40 DEG C and a pH of 2 to 7 by mixing an acidic aqueous solution such as hydrochloric acid or acetic acid with each diazo solution.

The monoazoamino compound and the disazoamino compound obtained by coupling may be precipitated as it is or directly separated by filtration or may be subjected to the next step in the form of solution or suspension. If the diazonium salt is poorly soluble and in the form of a suspension, it may be filtered and used as a press cake in the following coupling step.

(Ii) and / or (iv) having an alkoxy group having a sulfo group used in primary and secondary couplings can be produced by a method in which phenols are reacted with an aniline To give sulfoalkoxy anilines by sulfoalkylation and reduction, and can be used in the coupling step.

Specific methods of the ureidoation reaction of the disazoamino compound with phenyl chloroformate are carried out under neutral to alkaline conditions at a temperature of 10 to 90 ° C and a pH of 7 to 11 according to the production method described in Patent Document 3, page 57 . After completion of the reaction, the reaction product is precipitated by salting out, followed by filtration. If purification is necessary, salting out may be repeated or precipitation in water using an organic solvent. Examples of the organic solvent used for the purification include water-soluble organic solvents such as alcohols such as methanol and ethanol, and ketones such as acetone.

In addition, in the present invention, the azo compound represented by the above formula (1) can be used as a salt of an azo compound in addition to being used as a free acid. 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. Sodium salts are generally used.

One of the starting materials for synthesizing the water-soluble dye represented by the formula (1) is a naphthylamine having a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms having a sulfo group or a sulfo group: A-NH ₂ to be. Examples of the naphthyl amines: A-NH ₂ having a hydrogen atom, a hydroxyl group and a sulfo group include 4-aminonaphthalenesulfonic acid, 7-aminonaphthalene-3-sulfonic acid, Amino naphthalene-1, 3-disulfonic acid, 7-aminonaphthalene-1, 5-disulfonic acid, 7-aminonaphthalene- 3,6-trisulfonic acid and the like. Amino naphthalene-1,3-disulfonic acid, 7-aminonaphthalene-1,3-disulfonic acid, 7-aminonaphthalene-1,3-disulfonic acid, -Hydroxynaphthalene-6-sulfonic acid, 3-amino-8-hydroxynaphthalene-6-sulfonic acid, 1-aminonaphthalene-3,6,8-trisulfonic acid, Disulfonic acid, 1-aminonaphthalene-3,8-disulfonic acid, and the like. Examples of the naphthylamines having an alkoxy group having 1 to 5 carbon atoms and having a sulfo group and a sulfo group in the case where A is a compound represented by the formula (2) include, for example, 7-amino-3- Sulfonic acid, 7-amino-3- (5-sulfopentoxy) naphthalene-1-sulfonic acid, 7- Amino-4- (4-sulfobutoxy) naphthalene-2-sulfonic acid, 7-amino-4- (5-sulfophenoxy) Naphthalene-2-sulfonic acid, 6-amino-4- (3-sulfoproxyphenyl) naphthalene- - (5-sulfophenoxy) naphthalene-2-sulfonic acid, 2-amino-5- (3-sulfoproxy) naphthalene- ) Naphthalene-2,7-disulfonic acid, and 7-amino-3- (3-sulfoproxy) naphthalene-1,5-disulfonic acid.

In the 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, each of R ₁ to R ₄ independently represents a hydrogen atom, a lower alkyl group or a lower alkoxy group, more preferably a hydrogen atom, a methyl group, an ethyl group, a methoxy group or an ethoxy group, A methyl group, an ethyl group, and a lower alkoxy group having a sulfo group.

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

Examples of the anilines which are primary and / or secondary couplers include anilines such as aniline, 2-methylaniline, 2-ethylaniline, 2-propylaniline, 2-butylaniline, 3-methylaniline, Aniline, 3-butylaniline, 2,5-dimethylaniline, 2,5-diethylaniline, 2-methoxyaniline, 2-ethoxy aniline, 2-propoxyaniline, 2-butoxyaniline, 3- Aniline, 3-ethoxyaniline, 3-propoxyaniline, 3-butoxyaniline, 2-methoxy- Aniline or 3,5-dimethoxy aniline.

Other examples of the anilines which are primary and / or secondary couplers include 3- (2-amino-4-methylphenoxy) propane-1-sulfonic acid, 3- (2-aminophenoxy) Sulfonic acid, 4- (2-amino-4-methylphenoxy) butane-1-sulfonic acid, 4- Sulfonic acid, 3- (3-aminophenoxy) propane-1-sulfonic acid, 3- Sulfonic acid, 4- (3-amino-4-methylphenoxy) butane-1-sulfonic acid, 4- Sulfonic acid, 3- (2-amino-4-methoxyphenoxy) propane-1-sulfonic acid, 4- Sulfonic acid and 3- (3-amino-4-methoxyphenoxy) propane-1-sulfonic acid, (3-amino-4-methoxyphenoxy) butane-1-sulfonic acid, 2- (2-amino-4-ethoxyphenoxy) propane-1-sulfonic acid, 4- (3-amino-4-ethoxyphenoxy) propane-1-sulfonic acid, 4- (3-amino- Sulfonic acid, and 2- (3-amino-4-ethoxyphenoxy) ethane-1-sulfonic acid. Sulfonic acid, 3- (2-amino-4-methylphenoxy) propane-1-sulfonic acid, 3- Sulfonic acid, 2- (2-aminophenoxy) ethane-1-sulfonic acid, 2- Sulfonic acid, 3- (3-amino-4-methylphenoxy) propane-1-sulfonic acid, 3- Sulfonic acid, 2- (3-aminophenoxy) butane-1-sulfonic acid, 2- (2-amino-4-methoxyphenoxy) butane-1-sulfonic acid, - (2-amino-4-methoxyphenoxy) propane- Methoxyphenoxy) propane-1-sulfonic acid, 4- (3-amino-4-methoxyphenoxy) Sulfonic acid, 2- (3-amino-4-methoxyphenoxy) ethane-1-sulfonic acid, particularly preferably 3- -4-methylphenoxy) propane-1-sulfonic acid and 3- (2-amino-4-methylphenoxy) butane-1-sulfonic acid.

These anilines may be protected by an amino group. As the protecting group, there can be mentioned, for example, ω-methanesulfone group.

The dye-based polarizing film or the dye-based polarizing plate of the present invention may contain, in addition to the azo compound represented by the formula (1) or a salt thereof, used alone or in combination thereof, in combination with one or more other organic dyes do. There is no particular limitation on the organic dye to be incorporated, but it is preferable that the dye has high dichroism as a dye having an absorption property in a wavelength region different from the absorption wavelength region of the azo compound or its salt of the present invention. For example, City, Eye, Direct, Yellow, City, Eye, Direct, Yellow, City, Eye, Direct, Yellow, City, Eye, Direct, Orange, City, Child, Direct, Orange 71, City, Eye, Direct, Orange 107, City, Eye, Direct, Red 2, City, Eye, Direct, Red 31, City, Eye, Direct, Red 79, City, Eye, Direct, Red 81, City, Eye, Direct, Red 247, City, Eye, Direct, Blue 237, City, Eye, Direct, Blue 273, City, Eye, Direct, Blue 274, City, Eye, Direct Green 59, and the dyes described in Patent Documents 1 to 5, but it is more preferable to use the dyes developed for the polarizing plate as described in Patent Documents 1 to 5 . These pigments are used as free acids or salts of alkali metal salts (for example, Na salts, K salts, Li salts), ammonium salts, and amines.

When different organic dyes are used in combination, the types of dyes to be blended differ depending on the target polarizing film, the neutral color polarizing film, the liquid crystal projector color polarizing film, and other color polarizing films. The compounding ratio thereof is not particularly limited, but is generally in the range of 0.1 to 10 parts by mass, based on the mass of the azo compound of the formula (1) or the salt thereof, in total of at least one of the above organic dyes .

The azo compound represented by the above formula (1) or its salt is contained in a polarizing film base material (for example, a polymer film) along with other dyes if necessary, , A polarizing film having various colors or neutral colors can be produced. The resultant polarizing plate is provided with a protective film and a protective layer or AR (antireflection) layer and a support or the like are formed as necessary on the polarizing plate, and the liquid crystal projector, the electronic tabletop calculator, the clock, the notebook PC, the word processor, It is used in lenses and glasses such as navigation and indoors and outdoors instruments and indicators.

The polarizing film base material (polymer film) used in the dye-based polarizing film of the present invention is preferably a film made of a polyvinyl alcohol resin or a derivative thereof, and specific examples thereof include polyvinyl alcohol or a derivative thereof, , Olefins such as propylene, and unsaturated carboxylic acids such as crotonic acid, acrylic acid, methacrylic acid and maleic acid. Among them, a film comprising polyvinyl alcohol or a derivative thereof is preferably used from the viewpoints of dye adsorption and orientation. The thickness of the substrate is usually from 30 to 100 mu m, preferably from 50 to 80 mu m.

When such an azo compound of the formula (1) or a salt thereof is contained in such a polarizing film substrate (polymer film), a method of dyeing a polymer film is usually employed. The dyeing is carried out, for example, as follows. First, the azo compound or its salt of the present invention and, if necessary, other dyes are dissolved in water to prepare a dye bath. The dye concentration in the dye bath is not particularly limited, but is usually selected in the range of about 0.001 to 10% by mass. If necessary, a dyeing aid may be used. For example, it is preferable to use glaube at a concentration of about 0.1 to 10 mass%. The polymer film is immersed in the thus-prepared bath for 1 to 10 minutes to perform dyeing. The dyeing temperature is preferably about 40 to 80 占 폚.

The orientation of the azo compound or its salt of the formula (1) is carried out by stretching the dyed polymer film as described above. As the stretching method, any known method such as a wet method or a dry method may be used. The stretching of the polymer film may be carried out before dyeing, as the case may be. In this case, the orientation of the water-soluble dye is performed at the time of dyeing. The polymer film containing and orienting a water-soluble dye is subjected to post treatment such as boric acid treatment by a known method if necessary. Such post-processing 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 and the kind of the dye to be used, but generally the boric acid concentration of the aqueous solution of boric acid is set in the range of 0.1 to 15 mass%, preferably 1 to 10 mass% , And the treatment is carried out by immersing in a temperature range of 30 to 80 캜, preferably 40 to 75 캜 for 0.5 to 10 minutes. If necessary, an aqueous solution containing a cationic polymer compound may be subjected to a fix treatment as well.

The thus obtained dye-based polarizing film of the present invention can be made into a polarizing plate by bonding a transparent protective film having excellent optical transparency and mechanical strength to one or both of its surfaces. As the material for forming the protective film, for example, a cellulose acetate film or an acrylic film, a fluorine-based film such as a tetrafluoroethylene / propylene fluoride-based copolymer, a film made of a polyester resin, a polyolefin resin or a polyamide- Etc. are used. Preferably, a triacetylcellulose (TAC) film or a cycloolefin-based film is used. The thickness of the protective film is usually 40 to 200 占 퐉.

Examples of the adhesive that can be used for bonding the polarizing film and the protective film include a polyvinyl alcohol adhesive, a urethane emulsion adhesive, an acrylic adhesive, and a polyester-isocyanate adhesive, and a polyvinyl alcohol adhesive is preferable .

On the surface of the dye-based polarizing plate of the present invention, a further transparent protective layer may be formed. As the protective layer, for example, an acrylic-based or polysiloxane-based hard coat layer or a urethane-based protective layer can be given. In order to further improve the single plate light transmittance, it is preferable to form the AR layer on the protective layer. The AR layer can be formed by, for example, a material such as silicon dioxide or titanium oxide by vapor deposition or sputtering, or by thinly coating a fluorine-based material. The dye-based polarizing plate of the present invention can also be used as an elliptically polarizing plate to which a retardation plate is pasted.

The dye-based polarizing plate of the present invention thus constituted has a neutral color, is free from color leakage on the orthogonal direction in the wavelength region of the visible light region, has excellent polarization performance, and does not cause discoloration or deterioration of polarization performance even under high temperature and high humidity conditions And the light leakage on the orthogonal in the visible light region is small.

The neutral gray polarizing plate for vehicle use according to the present invention contains a dichroic dye together with an azo compound represented by the formula (1) or a salt thereof together with other organic dyes as necessary. The polarizing film used in the color polarizing plate for a liquid crystal projector of the present invention is also manufactured by the above-described manufacturing method. These materials are further used as a polarizing plate by attaching a protective film and, if necessary, forming a protective layer, an AR layer, a support or the like, and used as a neutral gray polarizing plate for in-vehicle use.

As a color polarizing plate for a liquid crystal projector, a polarizing plate for a liquid crystal projector is required to have a polarizing plate having a desired wavelength range (A. when using an ultra-high pressure mercury lamp; 420 to 500 nm for a blue channel, 500 to 580 nm for a green channel, 600 to 680 nm for a red channel, The average light transmittance of the single plate is 39% or more and the average light transmittance of the organic light emitting layer is in the range of 430 to 450 nm for the blue channel, 520 to 535 nm for the green channel, and 620 to 635 nm for the red channel) Is 0.4% or less, and more preferably the average plate transmittance of the single plate at the required wavelength range of the polarizing plate is 41% or more, the average transmittance at the orthogonality is 0.3% or less, more preferably 0.2% or less. More preferably, the polarizing plate has an average light transmittance of not less than 42% and an average light transmittance of not more than 0.1% on the orthogonal axis in the required wavelength range. The color polarizing plate for a liquid crystal projector of the present invention has brightness and excellent polarization performance as described above.

In addition, the average plate transmittance of the single plate is not particularly limited as long as the light rays in a specific wavelength range when natural light is incident on one polarizing plate on which a support such as an AR layer and a transparent glass plate is not formed (hereinafter simply referred to as a polarizing plate) Is an average value of transmittance. The average light transmittance on an orthogonal basis is an average value of light transmittance in a specific wavelength region when natural light is incident on two polarizing plates on which orthogonal alignment directions are arranged.

The neutral gray polarizing plate for vehicle use of the present invention is preferably a polarizing plate having the AR layer formed on the polarizing plate composed of the polarizing film and the protective film and having the AR layer attached thereto, And a polarizing plate to which a support is attached are more preferable.

The neutral gray polarizing plate for vehicle use of the present invention is usually used as a polarizing plate having a support. Since the support affixes the polarizing plate, it is preferable that the support has a plane portion, and since it is for optical use, a transparent substrate is preferable. Examples of the transparent substrate include an inorganic substrate and an organic substrate. The inorganic substrate includes inorganic substrates such as soda glass, borosilicate glass, quartz crystal substrate, sapphire substrate and spinel substrate, and inorganic substrates such as acrylic, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, An organic substrate such as a polymer may be mentioned, but an organic substrate is preferable. The thickness and size of the transparent substrate may be any desired size. In order to further improve the single plate light transmittance, it is preferable to form the AR layer on one or both surfaces of the support surface or the polarizing plate surface.

In order to produce a color polarizing plate having a support for on-vehicle use, for example, a transparent adhesive (adhesive) agent may be applied to a flat portion of the support, and then the dye-based polarizer of the present invention may be applied to the applied surface. Further, a transparent adhesive (adhesive) agent may be applied to the polarizing plate, and then the support may be attached to the coated surface. The adhesive (adhesive) agent used herein is preferably, for example, an acrylate ester. When this polarizing plate is used as an elliptically polarizing plate, the retardation plate side is usually affixed to the support side, but the polarizing plate side may be affixed to the transparent substrate.

That is, in the liquid crystal display for in-vehicle use using the dye-based polarizing plate of the present invention, the dye-based polarizing plate of the present invention is disposed on one or both of the incident side and the emitting side of the liquid crystal cell. The polarizing plate may or may not be in contact with the liquid crystal cell, but is preferably not in contact with the liquid crystal cell from the viewpoint of durability. In the case where the polarizing plate is in contact with the liquid crystal cell on the emission side, the dye-based polarizing plate of the present invention having a 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. From the viewpoint of durability, it is preferable that the dye-based polarizing plate of the present invention is disposed on either the incident side or the emission side of the liquid crystal cell. Further, the polarizing plate side of the dye- Is disposed on the light source side. The incident side of the liquid crystal cell refers to the light source side and the opposite side is referred to as the emission side.

In the liquid crystal display for use in a vehicle using the dye-based polarizing plate of the present invention, the liquid crystal cell to be used is, for example, an active matrix type, and liquid crystal is sealed (sealed) between a transparent substrate on which electrodes and TFTs are formed and a transparent substrate on which counter electrodes are formed ). Light emitted from a cold cathode tube lamp or a light source such as a white LED passes through a neutral gray polarizer and then is projected on a display screen through a liquid crystal cell, a color filter, and a neutral gray polarizer.

The neutral gray polarizing plate for vehicle use structured as described above is characterized in that it has excellent polarizing performance and does not cause discoloration or deterioration of polarization performance even in a high temperature and high humidity state in a vehicle.

Example

Hereinafter, the present invention will be described in more detail by way of examples, which are intended to be illustrative and not to be construed as limiting the present invention at all. The percentages and parts in the examples are on a mass basis unless otherwise noted.

(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, and then 6.9 parts of sodium nitrite was added, followed by stirring for 1 hour. To this solution, 24.5 parts of 3- (2-amino-4-methylphenoxy) propane-1-sulfonic acid dissolved in water was added, and sodium carbonate was added thereto while stirring at 30 to 40 ° C to adjust the pH to 5, The ring reaction was completed to obtain 50.4 parts of a monoazoamino compound represented by the following formula (30).

[Chemical Formula 20]

50.4 parts of the monoazo compound of the formula (79) is dispersed in 600 parts of water, 9.4 parts of 35% hydrochloric acid and then 6.2 parts of sodium nitrite are added and the mixture is diazotized by stirring at 25 to 30 ° C for 2 hours. Then, 22 parts of 3- (2-amino-4-methylphenoxy) propane-1-sulfonic acid dissolved in water was added thereto, and sodium carbonate was added thereto while stirring at 30 to 40 ° C to adjust the pH to 5, The ring reaction was completed to obtain 65.3 parts of a disazoamino compound represented by the following formula (80).

[Chemical Formula 21]

65.3 parts of the obtained disazoamino 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 占 폚 for 2 hours to form urea. Salting out with sodium chloride and filtration 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 a 20% aqueous pyridine solution was 486 nm.

(Example 2)

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

(Example 3)

In the same manner as in Example 1 except that 7-aminonaphthalene-1,3-disulfonic acid was changed to 30.3 parts of 7-aminonaphthalene-1,5-disulfonic acid in Example 1, Of azo compound (41.4 parts). The maximum absorption wavelength of this compound in a 20% aqueous pyridine solution was 523 nm.

(Example 4)

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

(Example 5)

In the same manner as the primary coupling of Example 1, 50.4 parts of the monoazoamino compound represented by the formula (79) was obtained.

50.4 parts of the monoazo compound of the formula (79) is dispersed in 600 parts of water, 9.4 parts of 35% hydrochloric acid and then 6.2 parts of sodium nitrite are added and the mixture is diazotized by stirring at 25 to 30 ° C for 2 hours. 10.9 parts of 2,5-dimethylaniline was added thereto, and the mixture was stirred at 30 to 40 ° C to adjust the pH to 3 by adding sodium carbonate. The mixture was stirred to complete the coupling reaction to obtain disazo amino 55.3 parts of a compound was obtained.

[Chemical Formula 22]

55.3 parts of the obtained disazoamino 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 캜 for 2 hours to yield an ureide. Salting out with sodium chloride and filtration 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)

35.3 parts of 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. The maximum absorption wavelength of this compound in a 20% aqueous pyridine solution was 480 nm.

(Example 7)

Aminopthalene-1,3-disulfonic acid was changed to 30.3 parts of 6-aminonaphthalene-1,3-disulfonic acid, and 2,5-dimethylaniline was changed to 3-methylaniline in Example 5, , 34.5 parts of the azo compound of the present invention represented by the formula (32) was obtained. The maximum absorption wavelength of this compound in a 20% aqueous pyridine solution 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, and then 6.9 parts of sodium nitrite was added, followed by stirring for 1 hour. 12.1 parts of 2,5-dimethylaniline was added thereto, and the mixture was stirred at 30 to 40 ° C to adjust the pH to 5 by adding sodium carbonate to complete the coupling reaction. Thus, a monoazoamino 39.2 parts of a compound was obtained.

(23)

50.4 parts of the monoazo compound of the formula (82) is dispersed in 600 parts of water, 9.4 parts of 35% hydrochloric acid and then 6.2 parts of sodium nitrite are added and stirred at 25 to 30 ° C for 2 hours for diazotization. And 19.6 parts of 3- (2-amino-4-methylphenoxy) propane-1-sulfonic acid was added thereto and the mixture was stirred at 30 to 40 ° C to adjust the pH to 5 by adding sodium carbonate. To obtain 55.3 parts of a disazoamino compound represented by the following formula (83).

&Lt; EMI ID =

55.3 parts of the obtained disazoamino 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 캜 for 2 hours to yield an ureide. Salting out with sodium chloride and filtration 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)

In the same manner as in Example 8 except that 7-aminonaphthalene-1,3-disulfonic acid was changed to 6-amino-4- (3-sulfoproxy) naphthalene-2-sulfonic acid in Example 8, Thereby obtaining 35.3 parts of the azo compound of the present invention represented by the formula (53). The maximum absorption wavelength of this compound in a 20% aqueous pyridine solution was 480 nm.

(Example 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 formula (54) was obtained. The maximum absorption wavelength of this compound in a 20% aqueous pyridine solution was 486 nm.

(Example 11)

(55) was obtained in the same manner as in Example 8 except that 7-aminonaphthalene-1,3-disulfonic acid was changed to 7-aminonaphthalene-1,5-disulfonic acid in Example 8. To obtain 35.7 parts of an azo compound. The maximum absorption wavelength of this compound in a 20% aqueous pyridine solution was 452 nm.

(Example 12)

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

(Example 13)

(57) was obtained in the same manner as in Example 8 except that 7-aminonaphthalene-1,3-disulfonic acid was changed to 6-aminonaphthalene-1,3-disulfonic acid in Example 8. To obtain 35.2 parts of an azo compound. The maximum absorption wavelength of this compound in a 20% aqueous pyridine solution was 453 nm.

(Example 14)

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

(Example 15)

A polyvinyl alcohol film having a thickness of 75 占 퐉 was immersed in an aqueous solution at 45 占 폚 at a concentration of 0.03% and 0.1% of the compound of the formula (6) obtained in Example 1 for 4 minutes. The film was stretched 5 times at 50 캜 in a 3% boric acid aqueous solution, washed with water while keeping the tension, and dried to obtain the polarizing film of the present invention.

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

(Example 16)

A polyvinyl alcohol film having a thickness of 75 占 퐉 was immersed in an aqueous solution at 45 占 폚 at a concentration of 0.03% and 0.1% of the compound of the formula (30) obtained in Example 5 for 4 minutes. The film was stretched 5 times at 50 캜 in a 3% boric acid aqueous solution, washed with water while keeping the tension, and dried to obtain the polarizing film of the present invention.

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

(Example 17)

A polyvinyl alcohol film having a thickness of 75 占 퐉 was immersed in an aqueous solution at 45 占 폚 at a concentration of 0.03% and 0.1% of the compound of the formula (52) obtained in Example 8 for 4 minutes. The film was stretched 5 times at 50 캜 in a 3% boric acid aqueous solution, washed with water while keeping the tension, and dried to obtain the polarizing film of the present invention.

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

The test method will be described below.

Measurement of the maximum absorption wavelength of the polarizing film and calculation of the polarization ratio were performed by measuring the parallel transmittance and the orthogonal transmittance at the time of polarization incidence using a spectrophotometer (U-4100 manufactured by Hitachi, Ltd.).

Here, the parallel transmittance (Ky) is a transmittance in the case where the absorption axis of the absolute polarizer is parallel to the absorption axis of the polarizing film, and the orthogonal transmittance (Kz) indicates the transmittance when the absorption axis of the polarizer and the absorption axis of the polarizing film are 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 measured values, the polarization ratio of each wavelength was calculated from the following equation (i), and the polarization ratio at the highest in the range of 380 to 780 nm and the maximum absorption wavelength (nm) thereof were obtained.

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

(Examples 18 to 20)

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

As shown in Table 1, the polarizing films prepared using these compounds all had a high polarization ratio.

(Examples 21 and 22)

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

As shown in Table 1, the polarizing films prepared using these compounds all had a high polarization ratio.

(Examples 23 to 28)

The polarizing films of the present invention were obtained in the same manner as in Example 17 except that the azo compounds (compounds of the above formulas (53) to (58)) described in Examples 9 to 14 were used instead of the compounds of the above formula (52). Table 1 shows the maximum absorption wavelength and the polarization ratio of the obtained polarizing film.

As shown in Table 1, the polarizing films prepared using these compounds all had a high polarization ratio.

(Test Example)

There is a contrast indicating the difference in luminance between the white display and the black display as one index indicating the quality of the image, and Examples 15 and 18 to 20; 16, 21 and 22; Table 2 shows the maximum absorption wavelength of the polarizing film obtained at 17 and 23 to 28 and the contrast at that time. Here, the contrast means the ratio of the parallel transmittance to the quadrature transmittance (contrast = parallel transmittance at the maximum absorption wavelength Ky / direct transmittance at the maximum absorption wavelength Kz), and the larger the value is, . The evaluation of the polarization performance was carried out by preparing samples so that the parallel transmittance of the maximum absorption wavelength of the polarizing film becomes the same. As shown in Table 2, all of the polarizing films prepared using these compounds had high contrast.

(Comparative Example 1)

A compound (4) in Patent Document 4 synthesized in the same manner as in Example 2 of Patent Document 4 was used instead of the compound of the present invention to prepare a polarizing film in the same manner as in Example 15 of the present invention, Respectively. As shown in Table 2, the compound of the present invention exhibited a high contrast in all of Comparative Example 1 and exhibited excellent polarization performance.

(Comparative Example 2)

A polarizing film was produced in the same manner as in Example 15 of the present invention using the compound (I-3) synthesized in the same manner as in the method described in Patent Document 5, instead of the compound of the present invention, and the contrast was calculated . As shown in Table 2, the compound of the present invention exhibited a high contrast in all of Comparative Example 2 and exhibited excellent polarization performance.

(Example 29)

A solution of the compound (6) obtained in Example 1 at an aqueous solution of 45% at a concentration of 0.2% of dye, 0.07% of Si · Direct · Orange 39, 0.02% of Si · Direct Blue 274 and 0.1% A polarizing film was produced in the same manner as in Example 15. [ The maximum absorption wavelength of the obtained polarizing film was 576 nm, the average transmittance of the single plate at 380 to 600 nm was 42%, the average light transmittance at the orthogonal distribution was 0.02%, and had a high degree of polarization.

A triacetylcellulose film (TAC film; manufactured by Fuji Photo Film Co., Ltd., trade name: TD-80U) was laminated on both sides of the polarizing membrane through an adhesive of a polyvinyl alcohol aqueous solution and the dye system of the present invention To obtain a polarizing plate (neutral gray polarizing plate). The polarizing plate of the present invention has a high polarization rate and exhibits durability over a long period of time even under high temperature and high humidity conditions. Also, the light fastness to long-time exposure was excellent.

(Example 30)

The compound (30) obtained in Example 5 was dissolved in an aqueous solution at 45 占 폚 at a concentration of 0.2% of dye, 0.07% of Si-Ir Direct Orange 39, 0.02% of Si-Direct Blue 274 and 0.1% A polarizing film was produced in the same manner as in Example 16 except that the polarizing film was used. The maximum absorption wavelength of the obtained polarizing film was 577 nm, the average transmittance of the single plate at 380 to 600 nm was 42%, the average light transmittance at the orthogonal position was 0.02%, and had a high degree of polarization.

A triacetylcellulose film (TAC film; manufactured by Fuji Photo Film Co., Ltd., trade name: TD-80U) was laminated on both sides of the polarizing membrane through an adhesive of a polyvinyl alcohol aqueous solution and the dye system of the present invention To obtain a polarizing plate (neutral gray polarizing plate). The polarizing plate of the present invention has a high polarization rate and exhibits durability over a long period of time even under high temperature and high humidity conditions. Also, the light fastness to long-time exposure was excellent.

Example 31

The compound (52) obtained in Example 8 was dissolved in an aqueous solution of 45 ° C at a concentration of 0.2% of dye, 0.07% of Si-Ir Direct Orange 39, 0.02% of Si-Direct Blue 274 and 0.1% A polarizing film was produced in the same manner as in Example 17. [ The maximum absorption wavelength of the obtained polarizing film was 575 nm, the mean plate transmittance at 380 to 600 nm was 42%, the average light transmittance at the orthogonal position was 0.02%, and had a high degree of polarization.

A triacetylcellulose film (TAC film; manufactured by Fuji Photo Film Co., Ltd., trade name: TD-80U) was laminated on both sides of the polarizing membrane through an adhesive of a polyvinyl alcohol aqueous solution and the dye system of the present invention To obtain a polarizing plate (neutral gray polarizing plate). The polarizing plate of the present invention has a high polarization rate and exhibits durability over a long period of time even under high temperature and high humidity conditions. Also, the light fastness to long-time exposure was excellent.

Claims (17)

(1)
[Chemical Formula 1]

(Wherein A is a naphthyl group having a hydrogen atom, a hydroxyl group, a sulfo group, and an alkoxy group having 1 to 5 carbon atoms and / or a sulfo group, and at least one of R ₁ to R ₄ is independently a sulfo group 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)
Or a salt thereof. The method according to claim 1,
In the above formula (1), the other R ₁ to R ₄ are each independently a hydrogen atom, a methyl group or a methoxy group. 3. The method according to claim 1 or 2,
(a) R ₁ is alkyl group which has a sulfo group an alkoxy group of 1 to 4, (b) R ₃ is having a sulfo group an alkoxy group having from 1 to 4 carbon atoms, or (c) R ₁ and R ₃ are each independently an alcohol Or an alkoxy group having 1 to 4 carbon atoms having a halogen atom, 4. The method according to any one of claims 1 to 3,
An azo compound or a salt thereof according to the above formula (1), wherein the lower alkoxy group having a sulfo group is a 3-sulfoproxy group. 5. The method according to any one of claims 1 to 4,
A is represented by the following formula (2)
(2)

(Wherein R ₅ is a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 5 carbon atoms having a sulfo group, or a sulfo group, and n is an integer of 1 to 3)
Or an azo compound or a salt thereof. (3)
(3)

(Wherein R ₆ is a hydrogen atom, a hydroxyl group, and / or an alkoxy group having 1 to 5 carbon atoms having a sulfo group, at least one of R ₇ to R ₁₀ is an alkoxy group having 1 to 4 carbon atoms, Each of R ₇ to R ₁₀ independently represents 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)
Or a salt thereof. The method according to claim 6,
An azo compound or a salt thereof, wherein R ₇ to R _{10 in} the formula (3) other than the alkoxy group having 1 to 4 carbon atoms having a sulfo group are each independently a hydrogen atom, a methyl group or a methoxy group. 8. The method according to claim 6 or 7,
(a) R ₈ is an alkoxy group having 1 to 4 carbon atoms having a sulfo group, (b) R ₁₀ is an alkoxy group having 1 to 4 carbon atoms having a sulfo group, or (c) R ₈ and R ₁₀ each independently Or an alkoxy group having 1 to 4 carbon atoms having a halogen atom, 9. The method according to any one of claims 6 to 8,
An azo compound or a salt thereof according to the above formula (3), wherein R ₆ is a hydrogen atom and x is 2. 10. The method according to any one of claims 6 to 9,
An azo compound or a salt thereof according to the above formula (3), wherein the alkoxy group having 1 to 4 carbon atoms having a sulfo group is a 3-sulfoproxy group. A dye-based polarizing film comprising a polarizing film substrate containing 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 containing at least one of the azo compound or salt thereof according to any one of claims 1 to 10 and an organic dye other than these. 13. The method according to claim 11 or 12,
Wherein the polarizing film substrate is a film comprising a polyvinyl alcohol resin or a derivative thereof. A dye-based polarizing plate obtainable by applying a transparent protective layer to at least one surface of the dye-based polarizing film according to any one of claims 11 to 13. 14. A polarizing plate for liquid crystal display, comprising the dye-based polarizing film according to any one of claims 11 to 13 or the dye-based polarizing plate according to claim 14. A neutral gray polarizing plate for in-vehicle use, comprising the dye-based polarizing film according to any one of claims 11 to 13, the dye-based polarizing plate according to claim 14, or the polarizing plate for liquid crystal display according to claim 15. A liquid crystal display device using the dye-based polarizing plate according to claim 14, the polarizing plate for liquid crystal display according to claim 15, or the neutral gray polarizing plate for vehicle use according to claim 16.