JP5678429B2 - Azo compound for anisotropic film, composition containing the compound, anisotropic film and polarizing element - Google Patents

Description

  The present invention relates to an azo compound having high dichroism useful for a polarizing plate provided in a display device such as a light control device, a liquid crystal device (LCD), and an organic electroluminescence device (OLED), and a composition containing the compound. The present invention relates to an object, an anisotropic film, and a polarizing element.

LCDs use linearly polarizing plates and circularly polarizing plates to control optical rotation and birefringence in display. In the OLED, a circularly polarizing plate is used for preventing reflection of external light.
Conventionally, iodine has been widely used as a dichroic substance in these polarizing plates (polarizing elements). However, since iodine has a high sublimation property, when used in a polarizing element, its heat resistance and light resistance are not sufficient. Further, the extinction color is deep blue, and it cannot be said to be an ideal achromatic polarizing element over the entire visible spectrum region.

Therefore, a polarizing element using an organic compound as a dichroic material has been studied. However, these organic compounds have a problem that only a polarizing element having a degree of dichroism considerably inferior to that of iodine can be obtained.
In an LCD that uses optical rotation and birefringence of light as a display principle, a polarizing element is an important component, and in recent years, a new polarizing element has been developed for the purpose of improving display performance and the like.

  One method is to dissolve or adsorb a dichroic organic compound (so-called dichroic dye) in a polymer material such as polyvinyl alcohol in the same way as a polarizing element containing iodine, and the film is oriented in one direction. A method of orienting a dichroic compound by stretching it into a film is mentioned. However, this method has a problem such that a process such as a stretching process is troublesome.

Therefore, other methods have recently attracted attention.
As this method, Non-Patent Document 1 forms a polarizing film (anisotropic film) by orienting a dichroic compound on a substrate such as glass or a transparent film by utilizing an intermolecular interaction of an organic compound. ing. However, it has been known that the method described in this document has a problem of heat resistance.

  Further, orienting the dichroic compound on the substrate such as glass or transparent film by utilizing the intermolecular interaction of the organic compound can be achieved by a wet film forming method. In addition to the high dichroism of the molecules used, this film is required to be a compound suitable for the wet film forming process. Examples of the process in the wet film forming method include a method of depositing and orienting a compound on a substrate and a method of controlling the orientation, and even a compound used for a polarizing element that has undergone the above-described conventional stretching treatment, Often not suitable for wet film formation.

In Patent Documents 1 to 4, various materials suitable for a wet film forming process are proposed.
In addition, as a material suitable for the process, Patent Document 4 proposes a dye represented by (chromogen) (SO ₃ M) n.

JP 2002-180052 A JP-T-2002-528758 JP 2002-338838 A JP-T 8-511109

Dreyer, J.A. F., Journal de Physique, 1969, 4, 114., “Light Polarization From Films of Lyotropic Nematic Liquid Crystals”

  The various materials proposed in Patent Documents 1 to 4 have a problem that high polarization characteristics (extinction ratio) cannot be obtained even though they are suitable for the process. These represent achromatic colors by combining several types of dichroic compounds, but when an anisotropic film is obtained by combining several types of dichroic compounds in this way, the molecular orientation is disturbed because different molecules are mixed. As a result, it is difficult to obtain high dichroism.

  The present invention provides an azo compound used for an anisotropic film formed by a wet film forming method, wherein the film becomes an anisotropic film exhibiting high dichroism and a high degree of molecular orientation. Is an issue.

As a result of intensive studies to solve the above problems, the present inventors have determined that an anisotropic film formed by a wet film-forming method by using an azo compound whose free acid form is represented by the following formula (1) In the present invention, an anisotropic film exhibiting high dichroism and a high degree of molecular orientation can be formed, and a polarizing element comprising the anisotropic film can be found to have high optical performance, thereby reaching the present invention. did.
That is, the present invention provides an anisotropic azo compound for an anisotropic film formed by a wet film-forming method, wherein the free acid form is represented by the following formula (1), a compound containing the compound and a solvent. The present invention resides in a composition for an isotropic film, an anisotropic film containing the compound, and a polarizing element comprising the anisotropic film.

(In the above formula (1), A ¹ represents a phenyl group having a carbamoyl group, an alkylcarbamoyl group which may have a substituent, or a phenylcarbamoyl group which may have a substituent .
B ¹ , D ¹ and E ¹ each independently represent a divalent aromatic hydrocarbon group which may have a substituent or a divalent heterocyclic group which may have a substituent, At least ^one of B ¹ and D ¹ represents a 1,4-naphthylene group.
R ¹ and R ¹ each independently represents a hydrogen atom, an alkyl group that may have a substituent, a phenyl group that may have a substituent, or an acyl group that may have a substituent. Represent.

  m and n represent 0 or 1. )

By using the azo compound of the present invention, an anisotropic film having high dichroism and a high degree of molecular orientation can be provided even in an anisotropic film formed by a wet film forming method. In addition, a polarizing element including an anisotropic film having such characteristics can be used in various fields such as a light control element, a liquid crystal element, and an organic electroluminescence element.

Hereinafter, embodiments of the present invention will be described in detail.
The description of the constituent requirements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not specified in these contents unless it exceeds the gist.
The anisotropic film as used in the present invention has anisotropy in electromagnetic properties in any two directions selected from a total of three directions in the three-dimensional coordinate system of the film thickness direction and any two orthogonal in-plane directions. It is a membrane. Examples of electromagnetic properties include optical properties such as absorption and refraction, and electrical properties such as resistance and capacitance. Examples of the film having optical anisotropy such as absorption and refraction include a linearly polarizing film, a circularly polarizing film, a retardation film, and a conductive anisotropic film.

The anisotropic film of the present invention is preferably used for a polarizing film, a retardation film, and a conductive anisotropic film, and more preferably used for a polarizing film.
The azo compound for anisotropic film of the present invention is a compound also having a function as a so-called dye, and the anisotropic film containing the azo compound for anisotropic film of the present invention can also function as a dye film. Is. In addition, generally a pigment | dye here means the compound which has absorption in a visible light wavelength range.

In the present specification, “may have a substituent” means that one or more substituents may be present.
Further, in the present specification, the “total number of carbon atoms of a substituent” represents the number of carbon atoms contained in the substituent, and when the substituent has a further substituent, It is all the carbon numbers including the carbon number contained in a substituent.

[Azo compound for anisotropic film]
The azo compound for an anisotropic film of the present invention is an azo compound for an anisotropic film formed by a wet film-forming method, wherein the form of the free acid is represented by the following formula (1): To do.

(In the above formula (1), A ¹ represents a phenyl group having at least one nonionic electron-withdrawing group as a substituent.
B ¹ , D ¹ and E ¹ each independently represent a divalent aromatic hydrocarbon group which may have a substituent or a divalent heterocyclic group which may have a substituent.
R ¹ and R ² each independently represent a hydrogen atom, an alkyl group that may have a substituent, a phenyl group that may have a substituent, or an acyl group that may have a substituent. Represent.
m and n represent 0 or 1. )

The azo compound for anisotropic film represented by the above formula (1) has a phenyl group (A ¹ arranged at the terminal).
) Has a nonionic electron-withdrawing group as a substituent, resulting in an electron-deficient state (electron density on the benzene ring is reduced), and a hydroxyl group and amino group arranged at the opposite end. An electron-rich naphthyl group substituted with a group (electron density on the benzene ring is enhanced) attracts strongly between the molecules, and the B ¹ , D ¹ , and E ¹ rings arranged at the center of the molecule Have the property that molecules tend to form an associated state by the π-π interaction between molecules. Therefore, this azo compound for anisotropic film is high in solution, such as a lyotropic liquid crystal required for an azo compound for anisotropic film by a wet film-forming method in a composition containing the compound. An association state can be formed. Even in an anisotropic film obtained by applying a process specific to the wet film formation method to the composition containing this azo compound, that is, a lamination process such as coating on the substrate surface, the azo compound of the present invention is It is considered that an anisotropic film that is arranged in high order and exhibits high dichroism can be provided.

Moreover, the azo compound represented by the formula (1) of the present invention has absorption in the entire visible light wavelength region, and an anisotropic film using this azo compound becomes achromatic. Therefore, the azo compound for an anisotropic film of the present invention can form an achromatic anisotropic film having high anisotropy.
Hereinafter, the azo compound for anisotropic films represented by the formula (1) of the present invention will be described.
<A ^1>
In the formula (1), A ¹ represents a phenyl group having at least one nonionic electron withdrawing group as a substituent.

  Here, the ionic group is a hydrophilic group as described in pages 33 to 35 of Hiroshi Suzuki, “Interface and Surfactant” (Sangyo Tosho Co., Ltd., issued on January 23, 1990). The group which dissociates in water and separates into an anion (anion) part and a cation (cation) part. Specifically, sulfo group, carboxy group, phosphate group, trimethylammonio group, etc. N. Israel Achivili, Yasu Kondo, Hiroyuki Oshima "Intermolecular forces and surface forces" (Maglow Hill Publishing Co., Ltd., published on December 25, 1991) pages 105-106, etc. . “Nonionic” substituents refer to those that are not ionic groups.

  In addition, the electron withdrawing group refers to a substituent that is easier to attract electrons from the bonding atom side than the hydrogen atom, and when the electron withdrawing group is substituted with a phenyl group, the electron density on the benzene ring is reduced, that is, , Has the effect of making electrons shortage. Examples of the electron-withdrawing group include a halogen atom, an atom having a multiple bond with a highly negative electron atom such as an oxygen atom or a nitrogen atom, a carbon atom substituted with a halogen atom, or a positively charged atom. . Examples of an indicator that the substituent is electron withdrawing include, for example, Kenzo Konishi and Nobuhiko Kuroki, “Synthetic Dye Chemistry” (Tsumari Shoten, published February 25, 1963), pages 23-25. It is mentioned that the substituent constant in the Hammett formula described is positive, and in the present invention, a substituent in which the substituent constant is positive in both the meta position and the para position is preferable.

  The nonionic electron withdrawing group attenuates the electron density of the benzene ring of the phenyl group, and when this compound is used in the composition for an anisotropic film described later, charge separation in water mainly used as a solvent. Therefore, the interaction with the solvent is small, and there is a strong interaction between molecules between the hydroxyl group located at the opposite end of the phenyl group and the electron-rich naphthyl group substituted with the amino group, and the molecules are in an associated state. It is easy to make. Note that the electron excess means a state in which the electron density on the benzene ring is enhanced.

Examples of the nonionic electron-withdrawing group include a halogen atom, an atom having a multiple electron bond with an atom having high electronegativity such as an oxygen atom and a nitrogen atom, and a carbon atom substituted with a halogen atom. Specifically, a halogen atom, a cyano group, a formyl group, an alkylcarbonyl group which may have a substituent, an arylcarbonyl group which may have a substituent, a carbamoyl group, or a substituent. An alkylcarbamoyl group which may have a substituent, an arylcarbamoyl group which may have a substituent, a nitro group, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, a sulfamoyl group And an optionally substituted alkylsulfamoyl group, an optionally substituted arylsulfamoyl group, an alkyl group substituted with a halogen atom, and the like.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and among them, a fluorine atom and a chlorine atom having high electronegativity are preferable.
The alkylcarbonyl group which may have a substituent is represented by —CO—R ³¹ , and R ³¹ represents an alkyl group which may have a substituent. In the alkyl group, the total carbon number of the substituent is usually 1 or more, usually 4 or less, preferably 2 or less. Examples of the group that may be substituted on the alkyl group include an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, and a halogen atom. Specific examples of the alkylcarbonyl group include an acetyl group and a propionyl group. It is done.

The arylcarbonyl group which may have a substituent is represented by —CO—R ³² , and R ³² represents a phenyl group or a naphthyl group which may have a substituent. In the phenyl group, the total carbon number of the substituent is usually 6 or more, usually 10 or less, preferably 8 or less. In the naphthyl group, the total carbon number of the substituent is usually 10 or more, usually 14 or less, preferably 12 or less. Examples of the group which may be substituted on the phenyl group and the naphthyl group include an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group and a halogen atom. Specific examples of the arylcarbonyl group include a benzoyl group and a naphthylcarbonyl group.

The alkylcarbamoyl group which may have a substituent is represented by —CO—NHR ³³ , and R ³³ represents an alkyl group which may have a substituent. Examples of the total number of carbon atoms of the preferred substituents of the alkyl group and the substituents that may be present are the same as those exemplified for the alkyl group of R ³¹ . Specific examples of the alkylcarbamoyl group include a methylcarbamoyl group and an ethylcarbamoyl group.

The arylcarbamoyl group which may have a substituent is represented by —CO—NHR ³⁴ , and R ³⁴ is a phenyl group which may have a substituent or a naphthyl group which may have a substituent. Represents. Examples of the total carbon number of the preferred substituents of the phenyl group and naphthyl group and the substituents that may be present are the same as those exemplified for the phenyl group and naphthyl group of R ³² . Specific examples of the arylcarbamoyl group include a phenylcarbamoyl group and a naphthylcarbamoyl group.

The alkylsulfonyl group which may have a substituent is represented by —SO ₂ —R ³⁵ , and R ^3
5 represents an alkyl group which may have a substituent. Examples of the total number of carbon atoms of the preferred substituents of the alkyl group and the substituents that may be present are the same as those exemplified for the alkyl group of R ³¹ . Specific examples of the alkylsulfonyl group include a methanesulfonyl group and an ethanesulfonyl group.

The arylsulfonyl group which may have a substituent is represented by —SO ₂ —R ³⁶ , and R ^3
6 represents a phenyl group which may have a substituent or a naphthyl group which may have a substituent. Examples of the total carbon number of the preferred substituents of the phenyl group and naphthyl group and the substituents that may be present are the same as those exemplified for the phenyl group and naphthyl group of R ³² . Specific examples of the arylcarbamoyl group include a phenylsulfonyl group and a tolylsulfonyl group.

The alkylsulfamoyl group which may have a substituent is represented by —SO ₂ —NHR ³⁷ , and R ³⁷ represents an alkyl group which may have a substituent. Examples of the total number of carbon atoms of the preferred substituents of the alkyl group and the substituents that may be present are the same as those exemplified for the alkyl group of R ³¹ . Specific examples of the alkylsulfamoyl group include a methylsulfamoyl group and an ethylsulfamoyl group.

The arylsulfamoyl group which may have a substituent is represented by —SO ₂ —NHR ³⁸ , and R ³⁸ may have a phenyl group which may have a substituent or a substituent. Represents a good naphthyl group. Examples of the total carbon number of the preferred substituents of the phenyl group and naphthyl group and the substituents that may be present are the same as those exemplified for the phenyl group and naphthyl group of R ³² . Specific examples of the arylsulfamoyl group include a phenylsulfamoyl group and a naphthylsulfamoyl group.

  The alkyl group substituted with a halogen atom usually has a total carbon number of 1 or more, usually 6 or less, preferably 4 or less. Examples of the halogen atom that may be substituted on the alkyl group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among them, a fluorine atom and a chlorine atom having high electronegativity are preferable. Specific examples of the alkyl group substituted with a halogen atom include a trifluoromethyl group, a difluoromethyl group, and a trichloromethyl group.

The phenyl group of A ¹ may further have other substituents as long as the above properties are not impaired. Specifically, the alkyl group and the substituent which may have a substituent may be substituted. An alkoxy group which may have, an amino group, an alkylamino group which may have a substituent, an arylamino group which may have a substituent, an acylamino group which may have a substituent, A hydroxyl group etc. are mentioned.

  The alkyl group which may have a substituent which the phenyl group has has a total carbon number of the substituent of usually 1 or more, usually 6 or less, preferably 4 or less. Examples of the group that may be substituted on the alkyl group include an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, and a halogen atom. Specific examples of the alkyl group include a lower alkyl group which may have a substituent such as a methyl group, an ethyl group, an n-propyl group, a hydroxyethyl group, or a 1,2-dihydroxypropyl group.

  The alkoxy group which may have a substituent which the phenyl group has has a total carbon number of the substituent of usually 1 or more, usually 6 or less, preferably 3 or less. Examples of the group that may be substituted on the alkoxy group include an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, and a halogen atom. Specific examples of the alkoxy group include a lower alkoxy group which may have a substituent such as a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, a hydroxyethoxy group, and a 1,2-dihydroxypropoxy group. Can be mentioned.

The alkylamino group which may have a substituent which the phenyl group has is represented by —NR ⁴¹ R ⁴² , R ⁴¹ represents an alkyl group which may have a substituent, and R ⁴² represents hydrogen. The alkyl group which may have an atom or a substituent is represented. In the alkyl group, the total carbon number of the substituent is usually 1 or more, usually 4 or less, preferably 2 or less. Examples of the group which may be substituted on the alkyl group include an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group and a halogen atom. Specific examples of the alkylamino group include a methylamino group, an ethylamino group, a propylamino group, and a dimethylamino group.

The arylamino group which may have a substituent which the phenyl group has is represented by —NR ⁴³ R ⁴⁴ , R ⁴³ represents a phenyl group or a naphthyl group which may have a substituent, R ⁴⁴ represents a hydrogen atom, an alkyl group which may have a substituent, a phenyl group which may have a substituent, or a naphthyl group which may have a substituent. Examples of the total number of carbon atoms of the preferred substituents of the alkyl group and the substituents that may be present are the same as those exemplified for the alkyl groups of R ⁴¹ and R ⁴² . In the phenyl group, the total carbon number of the substituent is usually 6 or more, usually 10 or less, preferably 8 or less. In the naphthyl group, the total carbon number of the substituent is usually 10 or more, usually 14 or less, preferably 12 or less. Examples of the group which may be substituted on the phenyl group and the naphthyl group include an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group and a halogen atom. Specific examples of the arylamino group include a phenylamino group, a diphenylamino group, a phenylmethylamino group, and a naphthylamino group.

The acylamino group which may have a substituent which the phenyl group has is represented by -NH-COR ⁴⁵ , and R ⁴⁵ may have an alkyl group which may have a substituent or a substituent. A good phenyl group or an optionally substituted naphthyl group is represented. In the alkyl group, the total carbon number of the substituent is usually 1 or more, usually 4 or less, preferably 2 or less. The phenyl group generally has 6 or more, usually 10 or less, preferably 8 or less carbon atoms in the substituent. In the naphthyl group, the total carbon number of the substituent is usually 10 or more, usually 14 or less, preferably 12 or less. Examples of the group which may be substituted on the alkyl group, the phenyl group and the naphthyl group include an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group and a halogen atom. Specific examples of the acylamino group include an acetylamino group and a benzoylamino group.

Among A ¹ described in detail above, the azo compound for anisotropic film of the present invention has a cyano group, a carbamoyl group, an alkylcarbamoyl group which may have a substituent, or a substituent as a substituent. A phenyl group having an optionally substituted phenylcarbamoyl group is preferable. Among these, a carbamoyl group, an alkylcarbamoyl group which may have a substituent, or a phenyl group having one phenylcarbamoyl group which may have a substituent is preferable.

  Since these groups have hydrogen bonding properties, when a phenyl group having these as substituents is strongly attracted between molecules with an electron-rich naphthyl group arranged at the opposite end, an amino group substituted on the naphthyl group It is preferable because it has a property of interacting with each other and promoting association between molecules. From the viewpoint of sufficiently attracting the naphthyl group disposed at the opposite end, it is preferable that these substituents are substituted at the 4-position of the phenyl group.

<B ¹ >
In the formula (1), B ¹ represents a divalent aromatic hydrocarbon group which may have a substituent or a divalent heterocyclic group which may have a substituent.
The aromatic hydrocarbon group for B ¹ is preferably a phenylene group or a naphthylene group, the phenylene group is a 1,4-phenylene group, and the naphthylene group is a 1,4-naphthylene group. It is preferable to show

  Examples of the substituent that the aromatic hydrocarbon group may have include an alkyl group that may have a substituent, an alkoxy group that may have a substituent, an amino group, and a substituent. An alkylamino group which may have a substituent, an arylamino group which may have a substituent, an acylamino group which may have a substituent, an alkylsulfonylamino group which may have a substituent, and a substituent; An arylsulfonylamino group which may have, a carbamoyl group, an alkylcarbamoyl group which may have a substituent, an arylcarbamoyl group which may have a substituent, a sulfamoyl group, and a substituent. Alkylsulfamoyl group or arylsulfamoyl group which may have a substituent, hydroxyl group, nitro group, sulfo group, carboxy group, cyano group and halogen atom And the like.

In the alkyl group which may have a substituent, the total carbon number of the substituent is usually 1 or more, usually 6 or less, preferably 4 or less. Examples of the group that may be substituted on the alkyl group include an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, a halogen atom, a sulfo group, and a carboxy group. Specific examples of the alkyl group include a lower alkyl group which may have a substituent such as a methyl group, an ethyl group, an n-propyl group, a hydroxyethyl group, or a 1,2-dihydroxypropyl group.

  The alkoxy group which may have a substituent has a total carbon number of the substituent of usually 1 or more, usually 6 or less, preferably 3 or less. Examples of the group which may be substituted on the alkoxy group include an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, a halogen atom, a sulfo group and a carboxy group. Specific examples of the alkoxy group include a lower alkoxy group which may have a substituent such as a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, a hydroxyethoxy group, and a 1,2-dihydroxypropoxy group. Can be mentioned.

The alkylamino group which may have a substituent is represented by —NR ⁵¹ R ⁵² , R ⁵¹ represents an alkyl group which may have a substituent, and R ⁵² represents a hydrogen atom or a substituent. It represents an alkyl group that may have. In the alkyl group, the total carbon number of the substituent is usually 1 or more, usually 4 or less, preferably 2 or less. Examples of the group that may be substituted on the alkyl group include an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, a sulfo group, a carboxy group, and a halogen atom. Specific examples of the alkylamino group include a methylamino group, an ethylamino group, a propylamino group, and a dimethylamino group.

The arylamino group which may have a substituent is represented by —NR ⁵³ R ⁵⁴ , R ⁵³ represents a phenyl group or a naphthyl group which may have a substituent, R ⁵⁴ represents a hydrogen atom, The alkyl group which may have a substituent, the phenyl group which may have a substituent, or the naphthyl group which may have a substituent is represented. Examples of the total carbon number of the preferred substituents of the alkyl group and the substituents that may be present are the same as those exemplified for the alkyl groups of R ⁵¹ and R ⁵² . In the phenyl group, the total carbon number of the substituent is usually 6 or more, usually 10 or less, preferably 8 or less. In the naphthyl group, the total carbon number of the substituent is usually 10 or more, usually 14 or less, preferably 12 or less. Examples of the group that may be substituted on the phenyl group and the naphthyl group include an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, a sulfo group, a carboxy group, and a halogen atom. Specific examples of the arylamino group include a phenylamino group, a diphenylamino group, a phenylmethylamino group, and a naphthylamino group.

Acylamino group which may have a substituent group is represented by -NH-COR ^55, R ⁵⁵ is an alkyl group which may have a substituent, and a phenyl group or a substituted have a substituent A naphthyl group which may have a group is represented. In the alkyl group, the total carbon number of the substituent is usually 1 or more, usually 4 or less, preferably 2 or less. The phenyl group generally has 6 or more, usually 10 or less, preferably 8 or less carbon atoms in the substituent. In the naphthyl group, the total carbon number of the substituent is usually 10 or more, usually 14 or less, preferably 12 or less. Examples of the group which may be substituted on the alkyl group, the phenyl group and the naphthyl group include an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, a sulfo group, a carboxy group and a halogen atom. Specific examples of the acylamino group include an acetylamino group and a benzoylamino group.

The alkylsulfonylamino group which may have a substituent is represented by —NH—SO ₂ R ⁶¹ , and R ⁶¹ represents an alkyl group which may have a substituent. Examples of the total carbon number of the preferred substituents of the alkyl group and the substituents that may be present are the same as those exemplified for the alkyl groups of R ⁵¹ and R ⁵² . Specific examples of the alkylsulfonylamino group include a methylsulfonylamino group and an ethylsulfonylamino group.

Optionally substituted aryl sulfonylamino group is represented by ^{_{-NH-SO 2 R 62, R}} 62 is an alkyl group which may have a substituent and may have a substituent It represents a naphthyl group which may have a phenyl group or a substituent. Examples of the total carbon number of preferred substituents of the phenyl group and naphthyl group and the substituents that may be present are the same as those exemplified for the phenyl group and naphthyl group of R ⁵³ and R ⁵⁴ . Specific examples of the arylsulfonylamino group include a benzenesulfonylamino group and a p-tolylsulfonylamino group.

The alkylcarbamoyl group which may have a substituent is represented by —CO—NHR ⁵⁶ , and R ⁵⁶ represents an alkyl group which may have a substituent. Examples of the total carbon number of the preferred substituents of the alkyl group and the substituents that may be present are the same as those exemplified for the alkyl groups of R ⁵¹ and R ⁵² . Specific examples of the alkylcarbamoyl group include a methylcarbamoyl group and an ethylcarbamoyl group.

The arylcarbamoyl group which may have a substituent is represented by —CO—NHR ⁵⁷ , and R ⁵⁷ is a phenyl group which may have a substituent or a naphthyl group which may have a substituent. Represents. Examples of the total carbon number of preferred substituents of the phenyl group and naphthyl group and the substituents that may be present are the same as those exemplified for the phenyl group and naphthyl group of R ⁵³ and R ⁵⁴ . Specific examples of the arylcarbamoyl group include a phenylcarbamoyl group and a naphthylcarbamoyl group.

The alkylsulfamoyl group which may have a substituent is represented by —SO ₂ —NHR ⁵⁸ , and R ⁵⁸ represents an alkyl group which may have a substituent. Examples of the total carbon number of the preferred substituents of the alkyl group and the substituents that may be present are the same as those exemplified for the alkyl groups of R ⁵¹ and R ⁵² . Specific examples of the alkylsulfamoyl group include a methylsulfamoyl group and an ethylsulfamoyl group.

The arylsulfamoyl group which may have a substituent is represented by —SO ₂ —NHR ⁵⁹ , and R ⁵⁹ may have a phenyl group which may have a substituent or a substituent. Represents a good naphthyl group. Examples of the total carbon number of preferred substituents of the phenyl group and naphthyl group and the substituents that may be present are the same as those exemplified for the phenyl group and naphthyl group of R ⁵³ and R ⁵⁴ . Specific examples of the arylsulfamoyl group include a phenylsulfamoyl group and a naphthylsulfamoyl group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and among them, a fluorine atom and a chlorine atom are preferable.
The aromatic hydrocarbon group for B ¹ may be unsubstituted or may have 1 to 5 substituents, and preferably has 1 to 2 substituents. Among the above, it is preferable in terms of associative improvement by interaction in forming a lyotropic liquid crystal to have a group having a small polarity such as an alkyl group, an alkoxy group, a hydroxyl group, a halogen atom or a group having hydrogen bonding properties. From the viewpoint of water solubilization, it preferably has a sulfo group.

As the heterocyclic group for B ¹ , a group derived from a monocyclic or bicyclic heterocyclic ring is preferable. Examples of atoms other than carbon constituting the heterocyclic group include a nitrogen atom, a sulfur atom and an oxygen atom, and a nitrogen atom is particularly preferable. When the heterocyclic group has a plurality of atoms constituting a ring other than carbon, these may be the same or different. Further, the heterocyclic group of B ¹ represents may have a substituent.

The heterocyclic group for B ¹ is more preferably a divalent heterocyclic group represented by the following formula (5-a) or (5-b). That is, it is a divalent linking group bonded at the 2,5- or 3,6-position of the nitrogen-containing aromatic six-membered ring represented by (5-a), or represented by (5-b) It is preferably a divalent linking group bonded at the substitution positions of a and d in the heterocyclic ring. By being such a heterocyclic group, the azo compounds represented by the formula (1) can easily exhibit an interaction.

(In the formula, Q ^{1 to} Q ⁴ each independently represent a carbon atom or a nitrogen atom, but one or two of Q ^{1 to} Q ⁴ are nitrogen atoms, and the rest are carbon atoms, and Q ¹ to Q ⁴ Q ⁴ may have a substituent.)

(Wherein X represents a divalent linking group containing a nitrogen atom, oxygen atom or sulfur atom in the main chain and forms a 5- to 7-membered ring, and the benzene ring may have a substituent).
In the above formula (5-b), that the divalent linking group X contains a nitrogen atom, an oxygen atom or a sulfur atom in the main chain means that a nitrogen atom, an oxygen atom is present on the ring formed by the divalent group. It means containing an atom or a sulfur atom. In addition, examples of the substituent that the divalent heterocyclic group represented by the above formula (5-a) or (5-b) may have are listed as substituents for the heterocyclic group of B ¹ described later. Is the same as

Examples of the divalent linking group represented by X in the formula (5-b) include -N = CH-CH = C-, -CO-NH-CO-, = N-S-N =,- CH = N—CH═CH— and the like can be mentioned. However, C and N in CH and NH may be substituted with a substituent such as an organic group (such as those listed as a substituent of the heterocyclic group of B ¹⁾ instead of H.
The divalent heterocyclic group represented by the above formula (5-a) is derived from pyridine, pyridazine, pyrimidine and pyrazine, and has a linking position with the azo group at the 2,5 or 3,6 position. The divalent heterocyclic group represented by the above formula (5-b) is derived from quinoline, isoquinoline, benzothiadiazole, phthalimide and the like, and the linking position with the azo group is (5-b And groups at the positions of a and d shown in FIG.

Specific examples include a pyridinediyl group, a quinolinediyl group, an isoquinolinediyl group, a benzothiadiazolediyl group, and a phthalimidodiyl group. Among these, a quinoline diyl group and an isoquinoline diyl group are preferable.
Among these, from the viewpoint of planarity of the entire compound, the heterocyclic group of B ¹ is preferably a group represented by the formula (5-b), and in particular, 5,8-quinolinediyl group and 5,8- An isoquinolinediyl group is preferred.

The above-described heterocyclic group for B ¹ may have a substituent.
The substituent that the heterocyclic group of B ¹ may have includes an alkyl group that may have a substituent, an alkoxy group that may have a substituent, an amino group, and a substituent. An alkylamino group which may have a substituent, an arylamino group which may have a substituent, an acylamino group which may have a substituent, a nitro group, a carboxy group, a sulfo group, a hydroxyl group, a cyano group, a halogen atom, etc. Is mentioned. The total number of carbon atoms of the preferred substituents of the alkyl group, alkoxy group, alkylamino group, arylamino group and acylamino group, and examples of preferred substituents and preferred specific examples thereof are as follows: B ¹ is an aromatic hydrocarbon group In this case, the examples are the same as those exemplified as the substituent that may be present.

The heterocyclic group of B ¹ may have 1 to 5 substituents, and is preferably unsubstituted or has 1 to 2 of these substituents. Among the Examples of the substituent of the heterocyclic group of B ^1, hydroxyl group from the viewpoint of water-solubilizing, a sulfo group, a carboxyl group is preferable.
Among B ¹ described in detail above, in the azo compound for anisotropic film of the present invention, a naphthylene group substituted with a sulfo group is preferable, and a 1,4-naphthylene group substituted with a sulfo group. More preferably. In these, association from the same plane direction as the molecular plane is inhibited by the sulfo group, while the naphthalene ring has a wide π-conjugate plane, so that association formation between the molecular planes easily occurs. For this reason, the number of molecules involved in the columnar aggregate formed by stacking molecules increases, that is, an anisotropic film having a high degree of molecular orientation can be obtained. In particular, when B ¹ is a naphthylene group, the aspect ratio (major / minor axis ratio of the molecule) of the whole molecule is reduced, and the force due to π-π interaction between molecules is increased, so that the effect of promoting association is great.

<D ¹ >
In the formula (1), D ¹ represents a divalent aromatic hydrocarbon group which may have a substituent or a divalent heterocyclic group which may have a substituent.
The divalent aromatic hydrocarbon group which may have a substituent of D ¹ or the divalent heterocyclic group which may have a substituent has the substituent of B ¹ It may be the same as the divalent aromatic hydrocarbon group which may be substituted or the divalent heterocyclic group which may have a substituent.

Among D ¹ , a naphthylene group substituted with a sulfo group is preferable, and a 1,4-naphthylene group substituted with a sulfo group is more preferable. The reason is the same as in the case of B ^1.
<E 1>
In the formula (1), E ¹ represents a divalent aromatic hydrocarbon group which may have a substituent or a divalent heterocyclic group which may have a substituent.

The divalent aromatic hydrocarbon group which may have a substituent of E ¹ or the divalent heterocyclic group which may have a substituent has the substituent of B ¹ It may be the same as the divalent aromatic hydrocarbon group which may be substituted or the divalent heterocyclic group which may have a substituent.
Among E ¹ , a naphthylene group substituted with a sulfo group is preferable, and a 1,4-naphthylene group substituted with a sulfo group is more preferable. The reason is the same as in the case of B ^1.

<Preferable combination of B ¹ , D ¹ and E ¹ >
In the azo compound for anisotropic film of the present invention represented by the formula (1), it is preferable that at least ^one of B ¹ , D ¹ and E ¹ is a naphthylene group substituted with a sulfo group, More preferably, it is a 1,4-naphthylene group substituted with a sulfo group.
When at least ^one of B ¹ , D ^1, and E ¹ is a naphthylene group substituted with a sulfo group, association from the same plane direction as the molecular plane is inhibited by the sulfo group, while the naphthalene ring has a wide π Since it has a conjugated plane, association formation between molecular planes is likely to occur. For this reason, the number of molecules involved in the columnar aggregate formed by stacking molecules increases, that is, an anisotropic film having a high degree of molecular orientation can be obtained.

In particular, when B ¹ is a naphthylene group, the aspect ratio of the whole molecule (major / minor axis ratio of the molecule) decreases, and the force due to π-π interaction increases between molecules, which is more preferable because the effect of promoting association is large. .
<R ¹ and R ² >
In the formula (1), R ¹ and R ² each independently have a hydrogen atom, an optionally substituted alkyl group, an optionally substituted phenyl group or a substituent. An acyl group that may be present.

The alkyl group which may have a substituent generally has a total carbon number of 1 or more and 6 or less, preferably 4 or less. The phenyl group which may have a substituent has a total carbon number of the substituent of usually 6 or more, usually 12 or less, preferably 10 or less, more preferably 8 or less.
Examples of the substituent that the alkyl group and the phenyl group may have include a hydroxyl group, a carboxy group, and a sulfo group.

The acyl group which may have a substituent is represented by -NH-COR ⁷¹ , and R ⁷¹ represents an alkyl group which may have a substituent or a phenyl group which may have a substituent. . In the alkyl group, the total carbon number of the substituent is usually 1 or more, usually 4 or less, preferably 2 or less. The phenyl group generally has 6 or more, usually 10 or less, preferably 8 or less carbon atoms in the substituent. Examples of the group which may be substituted on the alkyl group and the phenyl group include an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, a sulfo group and a carboxy group. Specific examples of the acyl group include an acetyl group and a benzoyl group.

In particular, when R ¹ and R ² are hydrogen atoms (NR ¹ R ² is an amino group), when R ¹ is a hydrogen atom and R ² is an alkyl group (NR ¹ R ² is an alkylamino group) And R ¹ is preferably a hydrogen atom and R ² is a phenyl group (NR ¹ R ² is a phenylamino group). However, from the viewpoint of easily exhibiting lyotropic liquid crystallinity, R ¹ Alternatively, R ² is preferably a hydrogen atom, an alkyl group having a carboxy group or a sulfo group, an acyl group having a carboxy group or a sulfo group. In particular, it is preferable that both R ¹ and R ² are hydrogen atoms from the viewpoint of easily exhibiting lyotropic liquid crystal properties at a relatively low concentration and excellent process suitability.

<M>
m represents 0 or 1. Preferably it is 1.
<N>
n represents 0 or 1. That is, the azo compound for anisotropic film of the present invention represented by the formula (1) is a trisazo compound or a tetrakisazo compound.

<Molecular weight>
The molecular weight of the azo compound for an anisotropic film of the present invention (hereinafter sometimes referred to as “azo compound of the present invention”) in which the form of the free acid is represented by the above formula (1) is 600 or more in the form of the free acid. Is preferable, 2000 or less is preferable, and 1500 or less is more preferable.
<Water-soluble>
The azo compound of the present invention is usually a water-soluble compound.

The azo compound of the present invention has a solubility in water of preferably 0.1% by weight or more, more preferably 0.5% by weight or more at room temperature and normal pressure, specifically at 25 ° C. and 1 atm. preferable. Further, the solubility is preferably 50% by weight or less, and more preferably 40% by weight or less. For example, as will be described later, when an anisotropic film is produced, it is common to use water, a water-miscible organic solvent, or a mixture of water and a water-miscible organic solvent as the solvent. For this reason, if the solubility of the compound in water is too low, it may be difficult to use for such purposes. Conversely, from the viewpoint of forming a favorable association state of the compound, it may be preferable that the solubility in water is not too high.

<Salt>
The azo compound of the present invention may be used as it is in the free acid form (free acid form) as shown by the formula (1), or a part of the acid group may be in a salt form. . Further, a salt type compound and a free acid type compound may be mixed. Moreover, when it is obtained in a salt form at the time of production, it may be used as it is or may be converted into a desired salt form. As the salt-type exchange method, a known method can be arbitrarily used, and examples thereof include the following methods.
1) A strong acid such as hydrochloric acid is added to an aqueous solution of an azo compound obtained in a salt form, and the azo compound is acidified in the form of a free acid, and then an alkali solution having a desired counter ion (for example, an aqueous lithium hydroxide solution). The method of neutralizing the acidic group of the compound and salt exchange.
2) A method of performing salt exchange in the form of a salting-out cake by adding a large excess of a neutral salt (for example, lithium chloride) having a desired counter ion to an aqueous solution of an azo compound obtained in a salt form.
3) An aqueous solution of an azo compound obtained in a salt form is treated with a strongly acidic cation exchange resin, and the azo compound is acidified in the form of a free acid, and then an alkaline solution having a desired counter ion (for example, hydroxide) A method in which an acidic group of a compound is neutralized with a lithium aqueous solution and salt exchange is performed.
4) A method of performing salt exchange by allowing an aqueous solution of an azo compound obtained in a salt form to act on a strongly acidic cation exchange resin previously treated with an alkaline solution having a desired counter ion (for example, an aqueous lithium hydroxide solution).

  Whether the acidic group of the azo compound for anisotropic film of the present invention takes a free acid form or a salt form depends on the pKa of the compound and the pH of the compound solution. Therefore, the acidic group of the azo compound for anisotropic film of the present invention has a free acid type, a salt type, a mixture of a free acid type and a salt type, or two or more types of salt types when there are two or more acidic groups. It can take various forms such as mixing. In particular, the acidic group of the azo compound in the anisotropic film is a preferable pH of the composition for an anisotropic film described later or a solution containing a dissociable salt of the base material containing the azo compound for the anisotropic film. Under the influence of this treatment, it may be a salt type different from that used in the step of forming the anisotropic film.

Examples of the salt type include salts of alkali metals such as Na, Li and K, ammonium salts which may be substituted with alkyl groups or hydroxyalkyl groups, and organic amine salts.
Examples of the alkyl group or hydroxyalkyl group which may be a substituent of the ammonium salt include a lower alkyl group having 1 to 6 carbon atoms and a lower alkyl group having 1 to 6 carbon atoms which are hydroxy-substituted. .

Examples of the organic amine include a lower alkyl amine having 1 to 6 carbon atoms, a hydroxy substituted lower alkyl amine having 1 to 6 carbon atoms, a carboxy substituted lower alkyl amine having 1 to 6 carbon atoms, and the like.
In the case of these salt types, the type is not limited to one type, and a plurality of types may be mixed. Moreover, multiple types may be mixed in one molecule of a compound, and multiple types may be mixed in the composition.

The preferred type of the acidic group of the azo compound for anisotropic film of the present invention varies depending on the production process of the azo compound, the content of the composition for anisotropic film described later and the preferred pH, etc., but has high solubility in water. Is necessary (for example, when a high compound concentration is required in the composition for anisotropic film in order to develop a lyotropic liquid crystal phase), a lithium salt, an ammonium salt, a triethylamine salt, a water-soluble group is present. It is preferable to have one or more substituted organic amine salts or salts thereof. On the other hand, when low solubility in water is required (for example, when a low-viscosity anisotropic film composition containing a low concentration of an azo compound is required, or when the compound is removed from a compound solution in an azo compound production process, In the case where it is desired to precipitate, it is preferable to have at least one of a free acid type, an alkaline earth metal salt such as sodium salt, potassium salt, calcium salt or the like or a salt thereof.

<Compound represented by Formula (2)>
The azo compound for an anisotropic film of the present invention represented by the formula (1) is preferably represented by the following formula (2).

(In the above formula (2), B ¹ , D ¹ , E ¹ , R ¹ , R ² and n are as defined in the above formula (1).
R ³ and R ⁴ each independently represent hydrogen, an alkyl group that may have a substituent, or a phenyl group that may have a substituent. )
That is, A ¹ in the formula (1) is a carbamoyl group, a phenyl group having an alkylcarbamoyl group which may have a substituent or a phenylcarbamoyl group which may have a substituent as a substituent at the 4-position. It is preferable that m is 1.

  Thus, when the carbamoyl group, the optionally substituted alkylcarbamoyl group or the optionally substituted phenylcarbamoyl group is substituted at the 4-position of the phenyl group, these carbamoyl groups and Due to the interaction with the sulfo group substituted at the 6-position of the naphthyl group arranged at the opposite end, it is easy to take an association state in which molecules are stacked vertically, and a great effect is obtained that the dichroism is remarkably improved. It is done. That is, the azo compound for anisotropic film represented by the above formula (2) is particularly preferable because of its good dichroism.

R ³ and R ⁴ are each independently hydrogen, an alkyl group which may have a substituent, or a phenyl group which may have a substituent. Among them, R ³ and R ⁴ are both hydrogen. Is preferred. That is, the substituent substituted on the phenyl group is preferably a carbamoyl group in which R ³ and R ⁴ are both hydrogen.
<Specific example>
Specific examples of the azo compound for an anisotropic film of the present invention include, but are not limited to, compounds having the structure shown below as the form of the free acid.

<Synthesis method>
The azo compound for anisotropic film of the present invention represented by the formula (1) can be produced according to a method known per se.
For example, the azo compound represented by the formula (I-1) can be produced according to the following steps (A) to (D).
(A) 4-aminobenzonitrile and 8-amino-2-naphthalenesulfonic acid (1,7-Cleves acid) are used in a conventional manner [for example, Yutaka Hosoda, “New dye chemistry” (December 21, 1973, Monoazo compound is produced through a diazotization and coupling step according to (published by Gihodo), page 396, page 409].
(B) The obtained monoazo compound is similarly diazotized by a conventional method, and subjected to a coupling reaction with 8-amino-2-naphthalenesulfonic acid (1,7-Cleves acid) to produce a disazo compound.
(C) Similarly, the obtained disazo compound is diazotized by a conventional method, and a coupling reaction with 8-amino-2-naphthalenesulfonic acid (1,7-Cleves acid) is performed to produce a trisazo compound.
(D) Similarly, the obtained trisazo compound is diazotized by a conventional method, subjected to a coupling reaction with 7-amino-1-naphthol-3,6-disulfonic acid (RR acid) and salted out with sodium chloride. The target azo compound represented by the formula (I-1) is obtained as a sodium salt.

The azo compound for an anisotropic film of the present invention is usually prepared as a composition for an anisotropic film which will be described later, and is suitably used for preparing an anisotropic film having high dichroism.
As a method for producing an anisotropic film using the azo compound for anisotropic film of the present invention, preferably, for example, the compound is dissolved in an appropriate solvent to form a film (for forming an anisotropic film). A composition (anisotropic film composition) was prepared, and this composition was used to form a film on the surface of various substrates such as a glass plate by a wet film formation method, and the compound contained in the composition was Examples of the method include orientation and lamination. The wet film forming method will be described in detail later.

The azo compound represented by the formula (1) is excellent in associative property and can form a high lyotropic liquid crystal state. Therefore, it is particularly suitable as an azo compound for an anisotropic film formed by a wet film formation method, and since its dichroic ratio is high, a composition containing the compound is used for the production of an anisotropic film. Thus, an anisotropic film having high dichroism can be obtained.
Below, the composition for anisotropic films containing the azo compound for anisotropic films of this invention is demonstrated. The composition for an anisotropic film of the present invention is a composition suitably used for producing an anisotropic film by a wet film forming method.

[Anisotropic film composition]
The composition for an anisotropic film of the present invention contains the azo compound for an anisotropic film of the present invention and a solvent, and the azo compound for an anisotropic film of the present invention is usually dissolved or dispersed in the solvent. It is.
In the anisotropic film composition of the present invention or in the anisotropic film of the present invention described in detail below, the azo compound for anisotropic film of the present invention can be used alone. The azo compound for anisotropic film of the present invention can be used in combination of two or more, or other dichroic substances can be used in combination. Furthermore, various compounding compounds, solvents, additives, and the like can be used in appropriate combination in order to give desired performance to the produced anisotropic film or to make a composition suitable for production.

<Compound compound>
In the composition for anisotropic film of the present invention, the color tone of the anisotropic film is adjusted, the associative property of the azo compound for the anisotropic film is improved, the durability of the anisotropic film is improved, and the defect For the purpose of reducing the above, a compounding compound may be used in combination with the azo compound for anisotropic film of the present invention.
Preferable examples of the compounds that can be used together with the azo compound of the present invention include azo compounds, anthraquinone compounds, amino acids, hydroxyamines and the like.

For example, C.I. I. Direct Yellow 12, C.I. I. Direct Yellow 34, C.I. I. Direct Yellow 86, C.I. I. Direct Yellow 142, C.I. I. Direct Yellow 132, C.I. I. Acid
Yellow 25, C.I. I. Direct Orange 39, C.I. I. Direct Orange 72, C.I. I. Direct Orange 79, C.I. I. Acid Orange 28, C.I. I. Direct Red 39, C.I. I. Direct Red 79, C.I. I. Direct Red 81, C.I. I. Direct Red 83, C.I. I. Direct Red 89, C.I. I. Acid Red 37, C.I. I. Direct Violet 9, C.I. I. Direct Violet 35, C.I. I. Direct Violet 48, C.I. I. Direct Violet 57, C.I. I. Direct Blue 1, C.I. I. Direct Blue 67, C.I. I. Direct Blue 83, C.I. I. Direct Blue 90, C.I. I. Direct Green 42, C.I. I. Direct Green 51, C.I. I. Direct Green 59 etc. are mentioned.

Further, an anthraquinone compound may be blended according to the methods described in JP 2007-199333 A and JP 2008-101154 A. Furthermore, a method described in JP 2006-3864 A or a method described in JP 2006-323377 A may be used.
As described in JP 2007-179933 A, a cation of 0.9 equivalents or more and 0.99 equivalents or less and a strongly acidic anion of 0.02 equivalents or more and 0.1 equivalents or less with respect to the acidic group of the azo compound. In the composition for anisotropic film, the time until the relaxation elastic modulus G decreases to 1/10 after 0.01 seconds after applying the strain is 0.1 second or less. By using the composition to become, it is possible to suppress defects in the anisotropic film.

Since such a composition tends to lower the pH, a buffer substance may be further added as necessary for the purpose of preventing corrosion of the production apparatus. Examples of buffer substances include weakly acid and base which are partially or completely neutralized as described in DD Perrin, B. Dempsey's "Selection and Application of Buffer", Kodansha Scientific (1981). It is done. Specific examples include phosphates, carbonates, organic acids, and the like, and examples of organic acids include malic acid, citric acid, oxalic acid, tartaric acid, amino acids, and the like. Of these, amino acids are preferably used because they promote the association of the azo compound for the anisotropic film and improve the orientation. In addition, an amino acid oligomer in which a plurality of amino acids are condensed is preferable because it also has a function as a rheology adjusting agent of the composition for anisotropic film, and an improvement in flow orientation can be expected by addition. When these buffer substances are used alone and crystallize on an anisotropic film, it is preferable to use a combination of a plurality of different buffer substances.

Furthermore, an ultraviolet absorber, a near infrared absorber, etc. can also be used in combination.
When the azo compound for anisotropic films of the present invention is used in combination with other compounds such as other dichroic substances and compounding compounds, the effects of the azo compound for anisotropic films of the present invention are sufficiently exerted. Therefore, the other combined compound is preferably 50% by weight or less, and more preferably 10% by weight or less based on the azo compound for anisotropic film of the present invention.

The pH of the anisotropic film composition thus obtained is usually about 2 to 10.
<Additives>
The anisotropic film composition of the present invention, for example, when used for application to a substrate as an anisotropic film forming solution in a wet film forming method described later, wettability to the substrate, In order to improve applicability, an additive such as a surfactant can be added as necessary. As the surfactant, any of anionic, cationic, and nonionic surfactants can be used. In addition to the above, known additives described in, for example, “Additives for Coating” (Edited by J. Bieleman, Willey-VCH, 2000) can be used. The concentration of the additive is sufficient to obtain the desired effect, and is an amount that does not inhibit the orientation of the azo compound for anisotropic film of the present invention and the compounding compound molecule used as necessary. The concentration in the composition for an isotropic film is usually more preferably 0.05% by weight or more and 0.5% by weight or less.

<Solvent>
As the solvent used in the composition for an anisotropic film of the present invention, water, a water-miscible organic solvent, or a mixture thereof is suitable. Specific examples of the organic solvent include alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol, polyhydric alcohols such as ethylene glycol, diethylene glycol, and glycerin, and cellosolves such as methyl cellosolve and ethyl cellosolve. The mixed solvent is mentioned.

<Concentration>
The concentration in the case of dissolving the azo compound for anisotropic film of the present invention and other compounds such as the above-mentioned compounding compounds and additives used as necessary includes the solubility of these solutes and the lyotropic liquid crystal state. Although it depends on the formation concentration of the association state, it is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, preferably 30% by weight or less, more preferably 20% by weight or less.

[Anisotropic film]
The anisotropic film of the present invention is characterized by containing the azo compound for anisotropic film of the present invention. The anisotropic film is preferably an anisotropic film formed by a wet film formation method. Usually, the anisotropic film of the present invention is obtained by depositing the anisotropic film composition of the present invention on a substrate by a wet film forming method.

As described above, the azo compound for an anisotropic film of the present invention represented by the formula (1) can form a high lyotropic liquid crystal state and can exhibit a high-order molecular orientation state, and has a high dichroism. Can show gender. Therefore, the anisotropic film of the present invention containing such an azo compound for anisotropic film of the present invention is a useful film exhibiting high dichroism.
Although the anisotropic film of the present invention exhibits a high dichroic ratio, the dichroic ratio is preferably 8 or more, more preferably 12 or more, and particularly preferably 15 or more.

In particular, when used for a polarizing film, a film having a neutral color tone is preferable. In the L * a * b * color system, √ {(a ^* ) ² + (b ^* ) ² } ≦ 30, preferably √ {(a ^* ) ² + (b ^* ) ² } ≦ 10, more preferably √ {(a ^* ) ² + (b ^* ) ² } ≦ 5, and the membrane has a transmittance of 35% or more, preferably Satisfying 40% or more, more preferably 44% or more is preferable as a display element, particularly as a polarizing element for a color display element.

<Wet deposition method>
In the present invention, an anisotropic film is produced by a wet film forming method. More preferably, it is produced by a wet film forming method using the composition for anisotropic film of the present invention.
The wet film-forming method referred to in the present invention is based on an anisotropic film compound through a process in which an anisotropic film composition is applied to various substrates such as a glass plate by some method and the solvent is dried. This is a method of orientation and lamination on a material. In the wet film formation method, when the composition itself containing a solvent is formed on a substrate, the compound itself self-associates in the composition or in the process of drying the solvent, thereby aligning in a small area. Happens. By applying an external field to this state, it is characterized in that an anisotropic film having desired performance is obtained by orienting in a certain direction in a macro region. This is different from the method based on the principle that a so-called polyvinyl alcohol (PVA) film or the like is dyed with a solution containing an anisotropic compound and stretched, and the compound is oriented only by a stretching process. Here, the external field includes the influence of the orientation treatment layer previously applied on the base material, shear force, magnetic field, and the like, and these may be used alone or in combination. Further, the process of forming the composition on the substrate, the process of aligning by applying an external field, and the process of drying the solvent may be performed sequentially or simultaneously.

Examples of the method for applying the anisotropic film composition on the substrate in the wet film forming method include a coating method, a dip coating method, an LB film forming method, and a known printing method. There is also a method of transferring the anisotropic film thus obtained to another substrate. Among these, in the present invention, it is preferable to use a coating method, and the coating method will be described in detail below.
The azo compound for an anisotropic film of the present invention can be in a state in which an aggregate is formed by a good intermolecular interaction such as a lyotropic liquid crystal state in the composition for an anisotropic film. Therefore, this was applied to a substrate such as glass or resin, a shearing force was applied at the same time or after application, or an orientation treatment layer was applied on the substrate in advance, and the influence was made. By drying the film, the azo compound for anisotropic film of the present invention and the compounding compound used as necessary can be oriented in a certain direction to obtain an excellent anisotropic film.

As the substrate, a transparent material having a thickness of about 10 to 1500 μm made of glass, resin or the like is used. Examples of the resin include triacetate, acrylic resin, polyester resin, triacetyl cellulose, urethane resin, and the like.
In order to control the orientation direction of the azo compound for an anisotropic film of the present invention in the composition for an anisotropic film and the aforementioned compounding compound molecule used as necessary, the surface of the base material is “ The alignment treatment layer may be applied by a known method described in “Liquid Crystal Handbook” (Maruzen Co., Ltd., issued on October 30, 2000), pages 226 to 239.

As a method for applying the composition for an anisotropic film on a substrate, a conventionally known method may be used. For example, Yuji Harasaki "Coating Engineering" (Asakura Shoten Co., Ltd., issued on March 20, 1971) Pages 253 to 277 or “Creation and Application of Molecular Coordinating Materials” supervised by Kunihiro Ichimura (CMC Publishing Co., Ltd., published on March 3, 1998), pages 118 to 149, etc. For example, a spin coating method, a spray coating method, a bar coating method, a roll coating method, a blade coating method, a free span coating method, a die coating method and the like may be mentioned on a substrate that has been previously subjected to an alignment treatment.

  By applying a shearing force to the azo compound for an anisotropic film of the present invention in the anisotropic film composition coated on a substrate and the compounding compound used as necessary, the azo compound of the present invention And the above-mentioned compound for compounding etc. used as needed orientate in a fixed direction. The bar coat, roll coat, blade coat, free span coat method, die coat method and the like are preferable because a shearing force can be applied simultaneously with application.

The temperature at the time of application of the anisotropic film composition to the substrate is preferably 0 ° C. or more and 80 ° C. or less, and the humidity is preferably about 10% RH or more and 80% RH or less.
The drying temperature is preferably 0 ° C. or more and 120 ° C. or less, and the humidity is preferably about 10% RH or more and 80% RH or less.
When forming an anisotropic film on a substrate by the above method, the thickness of the formed anisotropic film is usually a film thickness after drying, preferably 50 nm or more, more preferably 100 nm or more, preferably Is 50 μm or less, more preferably 1 μm or less.

The anisotropic film thus obtained may be insolubilized.
Insolubilization means a treatment step that suppresses elution of the compound from the film by reducing the solubility of the compound in the film, thereby increasing the stability of the film. For example, the difference in solubility depending on the salt form of the compound for anisotropic film of the present invention is as described above, and in this step, the treatment can be performed by utilizing such difference.

  Specifically, for example, a process of replacing ions with a lower valence with ions with a higher valence (for example, replacing a monovalent ion with a multivalent ion). As such a treatment method, for example, known methods such as treatment steps described in Yutaka Hosoda, “Theoretical Manufacturing Dye Chemistry” (Gihodo, 1957), pages 435 to 437 are used. Preferably, the obtained anisotropic film is treated by a method described in JP-A No. 2007-241267, etc. to form a film that is insoluble in water, such as ease of post-processing and durability. It is preferable from the viewpoint.

The transmittance of the anisotropic film in the visible light wavelength region is preferably 25% or more. The higher the transmittance, the better. It is preferably 35% or more, particularly 40% or more, and most preferably 44% or more. If the transmittance is low, it is difficult to use as a display element, particularly a polarizing element for a color display element.
Since the anisotropic film manufactured by such a method may have low mechanical strength, a protective layer is provided as needed. This protective layer is formed by laminating an anisotropic film with a transparent polymer film such as triacetate, acrylic, polyester, polyimide, triacetylcellulose, or urethane film, and is practically used.

In addition, when the anisotropic film of the present invention is used as a polarizing film or the like for various display elements such as LCDs and OLEDs, the film is formed directly on the electrode substrate or the like constituting these display elements. The base material made can be used as a constituent member of these display elements.
[Polarizing element]
The anisotropic film of the present invention functions as a polarizing film that obtains linearly polarized light, circularly polarized light, elliptically polarized light, etc. by utilizing the anisotropy of light absorption. By selecting a composition containing an azo compound for a film and the above-mentioned compounding dye used as necessary, it can be functionalized as various anisotropic films such as refractive anisotropy and conduction anisotropy. This type of polarizing element can be used for various applications.

The polarizing element of the present invention is provided with the above-described anisotropic film of the present invention, but may be a polarizing element comprising only an anisotropic film, or an anisotropic film may be formed on a substrate. The polarizing element provided may be sufficient. In the present invention, a polarizing element comprising an anisotropic film on a substrate is referred to as a polarizing element including the substrate.
When the anisotropic film of the present invention is formed on a substrate and used as a polarizing element, it may be used only with the substrate and the formed anisotropic film, and in addition to the protective layer as described above, Layers with optical functions such as adhesive layer or antireflection layer, alignment film, retardation film function, brightness enhancement film function, reflection film function, transflective film function, diffusion film function, etc. For example, layers having various functions may be laminated by a wet film formation method or the like, and used as a laminate.

These layers having an optical function can be formed, for example, by the following method.
The layer having a function as a retardation film is subjected to, for example, a stretching process described in JP-A-2-59703, JP-A-4-230704, or a process described in JP-A-7-230007. Or can be formed.
The layer having a function as a brightness enhancement film may be formed by forming a fine hole by a method as described in, for example, Japanese Patent Application Laid-Open Nos. 2002-169025 and 2003-29030, or the center of selective reflection. It can be formed by overlapping two or more cholesteric liquid crystal layers having different wavelengths.

The layer having a function as a reflective film or a transflective film can be formed using a metal thin film obtained by vapor deposition or sputtering. The layer having a function as a diffusion film can be formed by coating the protective layer with a resin solution containing fine particles.
The layer having a function as a retardation film or an optical compensation film can be formed by applying and aligning a liquid crystal compound such as a discotic liquid crystal compound or a nematic liquid crystal compound.

  The anisotropic film using the azo compound for anisotropic film of the present invention can be directly formed on a high heat-resistant substrate such as glass, and a high heat-resistant polarizing element can be obtained. Therefore, it can be suitably used not only for liquid crystal displays and organic electroluminescence displays, but also for applications requiring high heat resistance such as liquid crystal projectors and in-vehicle display panels.

EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example, unless the summary is exceeded.
In the following description, “part” means “part by weight”.
Further, in each of the following examples, the dichroic ratio of the anisotropic film was calculated by the following equation after measuring the transmittance of the anisotropic film with a spectrophotometer in which a prism polarizing element was arranged in the incident optical system. .

Dichroic ratio (D) = Az / Ay
Az = -log (Tz)
Ay = -log (Ty)
Tz: Transmittance of polarized light in the direction of the absorption axis of the anisotropic film Ty: Transmittance of polarized light in the direction of the polarization axis of the anisotropic film [Example 1]
8-amino-2-naphthalene dissolved in 600 parts by weight of 4-aminobenzonitrile and diazotized by adding 3.04 parts by weight of sodium nitrite under acidic conditions of hydrochloric acid to 200 parts by weight of water After coupling with 8.93 parts by weight of sulfonic acid (1,7-claveic acid) and pH = 2 to 3, neutralization and salting out were performed, and the precipitate was filtered to obtain a monoazo compound.

  This monoazo compound was dissolved in 300 parts by weight of N-methylpyrrolidone and 150 parts by weight of water, and diazotized by adding 3.04 parts by weight of sodium nitrite under acidic conditions of hydrochloric acid, and dissolved in 600 parts by weight of water. After coupling with 8.93 parts by weight of 2-naphthalenesulfonic acid (1,7-clebic acid) and pH = 2 to 3, neutralization and salting out were performed, and the precipitate was filtered to obtain a disazo compound. It was.

  This disazo compound was dissolved in 600 parts by weight of N-methylpyrrolidone and 400 parts by weight of water, and diazotized by adding 3.04 parts by weight of sodium nitrite under acidic conditions of hydrochloric acid and dissolved in 1200 parts by weight of water. Coupling was carried out with 19.6 parts by weight of -1-naphthol-3,6-disulfonic acid (RR acid) (purity: 65.5%) and pH = 9-10. After the reaction, a sodium salt of the compound (I-1) of the present invention represented by the following formula was obtained by suction filtration.

  An aqueous solution of the sodium salt of compound (I-1) is passed through a cation exchange resin (SK1BH, manufactured by Mitsubishi Chemical Corporation) to make a free acid, neutralized with an aqueous lithium hydroxide solution, concentrated and dried to give compound (I- The lithium salt of 1) was obtained. The maximum absorption wavelength (λmax) of this dye in a 10 ppm aqueous solution was 628 nm.

[Example 2]
8-amino-2-naphthalenesulfone dissolved in 240 parts by weight of 4-aminobenzamide and diazotized by adding 3.00 parts by weight of sodium nitrite under acidic conditions of hydrochloric acid to 200 parts by weight of water After coupling with 8.93 parts by weight of acid (1,7-clave acid) and pH = 2 to 3, neutralization and salting out were performed, and the precipitate was filtered to obtain a monoazo compound.

  The monoazo compound was dissolved in 220 parts by weight of N-methylpyrrolidone and 110 parts by weight of water, diazotized by adding 3.00 parts by weight of sodium nitrite under acidic conditions of hydrochloric acid, and dissolved in 200 parts by weight of water. After coupling with 8.93 parts by weight of 2-naphthalenesulfonic acid (1,7-claveic acid) at pH = 2 to 3, salting out was performed and the precipitate was filtered to obtain a disazo compound.

  This disazo compound was dissolved in 200 parts by weight of N-methylpyrrolidone and 260 parts by weight of water, and diazotized by adding 3.04 parts by weight of sodium nitrite under acidic conditions of hydrochloric acid, and dissolved in 400 parts by weight of water. Coupling was performed with 19.5 parts by weight of -1-naphthol-3,6-disulfonic acid (RR acid) (purity: 65.5%) at pH = 9-10. After the reaction, a sodium salt of the compound (I-3) of the present invention represented by the following formula was obtained by suction filtration.

  An aqueous solution of a sodium salt of compound (I-3) is passed through a cation exchange resin (SK1BH, manufactured by Mitsubishi Chemical Corporation) to form a free acid, neutralized with an aqueous lithium hydroxide solution, concentrated and dried to give compound (I- The lithium salt of 3) was obtained. The maximum absorption wavelength (λmax) of this dye in a 10 ppm aqueous solution was 627 nm.

[Example 3]
Sodium o-anisidine methanesulfonate dissolved in 240 parts by weight of 4-aminobenzamide and diazotized by adding 3.00 parts by weight of sodium nitrite under hydrochloric acid conditions to 200 parts by weight of water After coupling at 9.57 parts by weight and pH = 2 to 3, neutralization and salting out were performed, the precipitate was filtered, and the resulting cake was hydrolyzed in an aqueous sodium hydroxide solution at 60 ° C. to obtain a monoazo A compound was obtained.

  This monoazo compound was dissolved in 220 parts by weight of N-methylpyrrolidone and 110 parts by weight of water, diazotized by adding 3.00 parts by weight of sodium nitrite under acidic conditions of hydrochloric acid, and dissolved in 300 parts by weight of water. After coupling with 8.93 parts by weight of 2-naphthalenesulfonic acid (1,7-claveic acid) at pH = 2 to 3, salting out was performed and the precipitate was filtered to obtain a disazo compound.

  This disazo compound was dissolved in 200 parts by weight of N-methylpyrrolidone and 260 parts by weight of water, and diazotized by adding 3.00 parts by weight of sodium nitrite under acidic conditions of hydrochloric acid and dissolved in 400 parts by weight of water. Coupling was performed with 19.5 parts by weight of -1-naphthol-3,6-disulfonic acid (RR acid) (purity: 65.5%) at pH = 9-10. After the reaction, a sodium salt of the compound (I-7) of the present invention represented by the following formula was obtained by suction filtration.

  An aqueous solution of a sodium salt of compound (I-7) was passed through a cation exchange resin (SK1BH manufactured by Mitsubishi Chemical Corporation) to make a free acid, neutralized with an aqueous lithium hydroxide solution, concentrated and dried to give compound (I- The lithium salt of 7) was obtained. The maximum absorption wavelength (λmax) of this dye in a 10 ppm aqueous solution was 620 nm.

[Example 4]
The disazo compound obtained as the intermediate of Example 2 was dissolved in 480 parts by weight of N-methylpyrrolidone and 720 parts by weight of water, and diazotized by adding 3.41 parts by weight of sodium nitrite under acidic conditions of hydrochloric acid, and water 1200 After coupling with 8.93 parts by weight of 8-amino-2-naphthalenesulfonic acid (1,7-clebic acid) dissolved in parts by weight at pH = 2 to 3, salting out was performed and the precipitate was filtered. Thus, a trisazo compound was obtained.

  This trisazo compound was dissolved in 480 parts by weight of N-methylpyrrolidone and 600 parts by weight of water, diazotized by adding 3.45 parts by weight of sodium nitrite under acidic conditions of hydrochloric acid, and dissolved in 1200 parts by weight of water. Coupling was performed with 19.5 parts by weight of -1-naphthol-3,6-disulfonic acid (RR acid) (purity: 65.5%) at pH = 9-10. After the reaction, a sodium salt of the compound (I-10) of the present invention represented by the following formula was obtained by suction filtration.

An aqueous solution of a sodium salt of compound (I-10) is passed through a cation exchange resin (SK1BH, manufactured by Mitsubishi Chemical Corporation) to make a free acid, neutralized with an aqueous lithium hydroxide solution, concentrated and dried to give compound (I- The lithium salt of 10) was obtained. The maximum absorption wavelength (λ _max ) of this dye in a 10 ppm aqueous solution was 648 nm.

[Example 5]
The anisotropic film composition is prepared by adding 13 parts of the lithium salt of the azo compound represented by the formula (I-1) to 87 parts of water, stirring and dissolving, and then filtering to remove insolubles. Got. On a glass substrate (75 mm × 25 mm, 1.1 mm thickness, about 80 nm polyimide alignment film previously rubbed with a cloth) with a polyimide alignment film formed on the surface by spin coating, The above anisotropic film composition was applied with an applicator (manufactured by Horita Seisakusho) with a gap of 4 μm, and then naturally dried to obtain an anisotropic film.

With respect to the obtained anisotropic film, the maximum absorption wavelength (λ _max ) and the dichroic ratio (D) were measured. The results are shown in Table 1 below. The anisotropic film of this example had a high dichroic ratio (light absorption anisotropy) that can function sufficiently as a polarizing film.
[Example 6]
The composition for anisotropic film is obtained by adding 12 parts of lithium salt of the azo compound represented by the formula (I-3) to 88 parts of water, stirring and dissolving, and then filtering to remove insolubles. I got a thing. Using the composition, an anisotropic film was obtained in the same manner as in Example 5.

With respect to the obtained anisotropic film, the maximum absorption wavelength (λ _max ) and the dichroic ratio (D) were measured. The results are shown in Table 1 below. The anisotropic film of this example had a high dichroic ratio (light absorption anisotropy) that can function sufficiently as a polarizing film.
[Example 7]
By adding 12 parts of a lithium salt of the azo compound represented by the formula (I-7) to 88 parts of water, stirring and dissolving, and then filtering to remove insolubles, the composition for anisotropic film I got a thing. Using the composition, an anisotropic film was obtained in the same manner as in Example 5.

With respect to the obtained anisotropic film, the maximum absorption wavelength (λ _max ) and the dichroic ratio (D) were measured. The results are shown in Table 1 below. The anisotropic film of this example had a high dichroic ratio (light absorption anisotropy) that can function sufficiently as a polarizing film.
[Example 8]
By adding 10 parts of the lithium salt of the azo compound represented by the above formula (I-10) to 90 parts of water, stirring and dissolving, and then filtering to remove insolubles, the composition for anisotropic film I got a thing. Using the composition, an anisotropic film was obtained in the same manner as in Example 5.

With respect to the obtained anisotropic film, the maximum absorption wavelength (λ _max ) and the dichroic ratio (D) were measured. The results are shown in Table 1 below. The anisotropic film of this example had a high dichroic ratio (light absorption anisotropy) that can function sufficiently as a polarizing film.
[Example 9]
In 85.5 parts of water, 13 parts of a lithium salt of the azo compound represented by the formula (I-3), 1 part of an 80 mol% lithium neutralized salt of the azo compound represented by the formula (I-3), After adding 0.5 part of lithium chloride and dissolving by stirring, the composition for anisotropic membrane was obtained by filtering and removing an insoluble matter. Using the composition, an anisotropic film was obtained in the same manner as in Example 5.

With respect to the obtained anisotropic film, the maximum absorption wavelength (λ _max ) and the dichroic ratio (D) were measured. The results are shown in Table 1 below. The anisotropic film of this example had a high dichroic ratio (light absorption anisotropy) that can function sufficiently as a polarizing film.
[Example 10]
To 78.83 parts of water, 14.9 parts of a lithium salt of an azo compound represented by the formula (I-3), 80 mol% lithium neutralized salt of an azo compound represented by the formula (I-3) 1.1 Part, lithium chloride 0.57 part, Tokyo Kasei Co., Ltd. 4.6 parts taurine, after stirring and dissolving, by filtration to remove insoluble matter, an anisotropic film composition was obtained. . Using the composition, an anisotropic film was obtained in the same manner as in Example 5.

With respect to the obtained anisotropic film, the maximum absorption wavelength (λ _max ) and the dichroic ratio (D) were measured. The results are shown in Table 1 below. The anisotropic film of this example had a high dichroic ratio (light absorption anisotropy) that can function sufficiently as a polarizing film.

[Example 11]
In 83 parts of water, 3.7 parts of a lithium salt of the azo compound represented by the formula (I-3), 7.3 parts of a 50 mol% lithium neutralized salt of the azo compound represented by the formula (I-3), By adding 0.458 parts of lithium chloride, 1.8 parts of Tokyo Chemical Co., Ltd. glycine, and 3.7 parts of Tokyo Chemical Industry Co., Ltd. glycylglycylglycine, stirring and dissolving, then filtering to remove insolubles Thus, a composition for an anisotropic film was obtained. Using the composition, an anisotropic film was obtained in the same manner as in Example 5.

With respect to the obtained anisotropic film, the maximum absorption wavelength (λ _max ) and the dichroic ratio (D) were measured. The results are shown in Table 2 below. The anisotropic film of this example had a high dichroic ratio (light absorption anisotropy) that can function sufficiently as a polarizing film.
[Example 12]
81.8 parts of water, 2 parts of a lithium salt of an azo compound represented by the formula (I-10), 10 parts of a 50 mol% lithium neutralized salt of an azo compound represented by the formula (I-10), lithium chloride 0.2 parts, 2 parts of Tokyo Chemical Co., Ltd. glycine, 4 parts of Tokyo Chemical Industry Co., Ltd. glycylglycylglycine, after stirring and dissolving, filtered to remove insolubles, for anisotropic membrane A composition was obtained. Using the composition, an anisotropic film was obtained in the same manner as in Example 5.

With respect to the obtained anisotropic film, the maximum absorption wavelength (λ _max ) and the dichroic ratio (D) were measured. The results are shown in Table 2 below. The anisotropic film of this example had a high dichroic ratio (light absorption anisotropy) that can function sufficiently as a polarizing film.

Claims (6)

An azo compound for an anisotropic film formed by a wet film forming method, wherein the form of a free acid is represented by the following formula (1).

(In the above formula (1), A ¹ represents a phenyl group having a carbamoyl group, an alkylcarbamoyl group which may have a substituent, or a phenylcarbamoyl group which may have a substituent .
B ¹ , D ¹ and E ¹ each independently represent a divalent aromatic hydrocarbon group which may have a substituent or a divalent heterocyclic group which may have a substituent, At least ^one of B ¹ and D ¹ represents a 1,4-naphthylene group.
R ¹ and R ² each independently represent a hydrogen atom, an alkyl group which may have a substituent, a phenyl group which may have a substituent, or an acyl group which may have a substituent. Represent. m and n represent 0 or 1. ) B ^1, D ¹ and E ¹ are each independently anisotropic film for azo compound according to claim 1, characterized in that a phenylene group or a naphthylene group. The azo compound for an anisotropic film according to claim 1 or 2 , wherein in the formula (1), B1 is a 1,4-naphthylene group substituted with a sulfo group. An anisotropic film composition comprising the azo compound for an anisotropic film according to any one of claims 1 to 3 and a solvent. An anisotropic film comprising the azo compound for anisotropic film according to any one of claims 1 to 4 . A polarizing element comprising the anisotropic film according to claim 5 .