JP2006328157A - Dye for anisotropic dye film, anisotropic dye film and polarizing element - Google Patents

Abstract

（式中、Ｘは色素骨格を表し、ｎは２以上の整数を表し、Ｙは直接結合、Ｏ、Ｓ、ＮＨ、ＮＣＨ_３を表し、Ｚは、直接結合、置換基を有していてもよい炭素数１〜１０のアルキレン基、置換基を有していてもよい(-CH₂CH₂O-)_ｍ基（ｍは１〜４の整数を表す）又は置換基を有していてもよい(-CH₂CH₂O-)_ｍ’(-CH₂-)_ｍ’’基（ｍ’は１〜４の整数、ｍ’’は１〜４の整数を表す）を表し、Ａｒ^１及びＡｒ^２は、それぞれ独立に、置換基を有していてもよい芳香族炭化水素基又は置換基を有していてもよい芳香族複素環基を表す。なお、一分子中に含まれる複数のＹ、Ｚ、Ａｒ^１及びＡｒ^２は、それぞれ同一であっても異なっていてもよい。）
【選択図】 なしPROBLEM TO BE SOLVED: To provide a dye that forms a good association state such as lyotropic liquid crystal in a solution.
A dye for an anisotropic dye film represented by the following general formula (1):

(In the formula, X represents a dye skeleton, n represents an integer of 2 or more, Y represents a direct bond, O, S, NH, NCH ₃ , and Z may have a direct bond or a substituent. alkylene group having 1 to 10 carbon atoms, which may have an optionally substituted (where m represents an integer of _{1~4) (-CH 2 CH 2 O-} ) m group or a substituted group Represents a good (—CH ₂ CH ₂ O—) _{m ′} (—CH ₂ —) _{m ″} group (where m ′ represents an integer of 1 to 4 and m ″ represents an integer of 1 to 4), Ar ¹ and Ar ² each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, and a plurality of which are included in one molecule. Y, Z, Ar ¹ and Ar ² may be the same or different.)
[Selection figure] None

Description

  The present invention relates to a dye useful for an anisotropic dye film such as a polarizing plate provided in a display element such as a light control element, a liquid crystal element, or an organic electroluminescence element. Specifically, the present invention relates to a dye for an anisotropic dye film excellent in forming a molecular aggregate, an anisotropic dye film having a high molecular orientation and a polarizing element formed using the dye.

In a liquid crystal display (LCD), a linearly polarizing plate and a circularly polarizing plate are used to control optical rotation and birefringence in display. Moreover, also in an organic electroluminescence (EL) element (OLED), a circularly polarizing plate is used for preventing reflection of external light.
Conventionally, iodine has been widely used in these polarizing plates as a dichroic substance. However, since iodine has a high sublimation property, when used as a polarizing plate, its heat resistance and light resistance are not sufficient. Therefore, a polarizing plate using an organic dye as a dichroic material has been studied.

As one of the methods for producing a polarizing plate, a dichroic dye is dissolved or adsorbed in a polymer material such as polyvinyl alcohol and stretched in one direction to form a film, and the dichroic dye is stretched. A method of aligning in the direction (stretching method) can be mentioned.
As another method, a coating solution containing a dichroic dye is applied to a substrate such as glass or a transparent film to form a film, and the two molecules in the film are used by utilizing the intermolecular interaction of the dye. The method (coating method) which orients chromatic pigment | dye is mentioned. (Patent Document 1)
JP-T 8-511109

  The coating method is attracting attention because a polarizing plate that is thin and excellent in heat resistance can be manufactured at a lower cost than the stretching method. In the coating method, if a dichroic dye that can form a dye aggregate by a good intermolecular interaction as typified by a lyotropic liquid crystal state in the coating liquid is used, the light distribution is good. It is known that a polarizing plate can be obtained. As such a dichroic dye, Patent Document 1 proposes a dye having a specific water-soluble condensed polycyclic skeleton, but further development of the dye is desired.

As a result of intensive studies by the present inventors, a dye having a plurality of triazinyl groups has a high molecular associative property, and forms a good association state typified by a lyotropic liquid crystal in a solution by intermolecular interaction. The inventors have found that a dye film having a good molecular orientation and high anisotropy can be obtained by forming an anisotropic dye film using a solution containing this dye as a coating solution, and the present invention has been achieved.
That is, the gist of the present invention resides in an anisotropic dye film dye represented by the following general formula (1).

(In the formula, X represents a dye skeleton, n represents an integer of 2 or more, Y represents a direct bond, O, S, NH, NCH ₃ , and Z may have a direct bond or a substituent. alkylene group having 1 to 10 carbon atoms, which may have an optionally substituted (where m represents an integer of _{1~4) (-CH 2 CH 2 O-} ) m group or a substituted group Represents a good (—CH ₂ CH ₂ O—) _{m ′} (—CH ₂ —) _{m ″} group (where m ′ represents an integer of 1 to 4 and m ″ represents an integer of 1 to 4), Ar ¹ and Ar ² each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, and a plurality of which are included in one molecule. Y, Z, Ar ¹ and Ar ² may be the same or different.)

  Since the dye according to the present invention forms a good association state such as lyotropic liquid crystal in a solution, an anisotropic dye film having a good molecular orientation state and high anisotropy can be produced by a coating method. . In addition, since the anisotropic dye film containing the dye according to the present invention exhibits high dichroism, when it is used as a polarizing plate of a liquid crystal display device, a high contrast display can be performed.

The description of the constituent requirements described below is an example (representative example) of the embodiment of the present invention, and the contents are not specified.
The dye for anisotropic dye films according to the present invention is represented by the following general formula (1).

(In the formula, X represents a dye skeleton, n represents an integer of 2 or more, Y represents a direct bond, O, S, NH, NCH ₃ , and Z may have a direct bond or a substituent. alkylene group having 1 to 10 carbon atoms, which may have an optionally substituted (where m represents an integer of _{1~4) (-CH 2 CH 2 O-} ) m group or a substituted group Represents a good (—CH ₂ CH ₂ O—) _{m ′} (—CH ₂ —) _{m ″} group (where m ′ represents an integer of 1 to 4 and m ″ represents an integer of 1 to 4), Ar ¹ and Ar ² each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, and a plurality of which are included in one molecule. Y, Z, Ar ¹ and Ar ² may be the same or different.)

The dye in the present invention refers to a compound that absorbs light in the visible region of 380 nm to 780 nm and produces a color.
X is a dye skeleton bonded to n Z through Y. In the present invention, the dye skeleton refers to a structure that absorbs light in the visible region to generate a color, that is, a dye residue. Examples of the dye skeleton include azo-based, stilbene-based, cyanine-based, phthalocyanine-based, and condensed polycyclic systems. Among them, azo-based and condensed polycyclic-based dye skeletons are preferable. These dye skeletons may have a substituent. Specific examples of the substituent include a hydroxyl group, an amino group, an alkylamino group, an arylamino group, an alkyl group, an alkoxy group, a nitro group, a sulfo group, A carboxy group, an amide group, a halogen atom, etc. are mentioned.

  The azo dye skeleton may be an organic compound having an azo group and absorbing in the visible region. The number of azo groups contained in the azo dye skeleton is preferably 2 or more, but may be 1. The upper limit is preferably 6 or less, particularly 4 or less. As the azo dye skeleton, those represented by the following general formula (2) are particularly preferable.

Ring A to ring D each independently represent a benzene ring or a naphthalene ring.
Each of these rings has an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a hydroxyl group, a nitro group, a sulfo group, a carboxy group, a halogen atom, and a substituent. It may have a substituent selected from the group consisting of an amino group which may be substituted, an amide group which may have a substituent, and a cyano group. Each of the sulfo group and the carboxy group may be a salt such as Li, Na, K, NH ₄ or the like.

The alkyl group usually has 1 or more carbon atoms, usually 4 or less, and preferably 2 or less. Examples of the group that may be substituted with an alkyl group include an alkoxy group, a hydroxyl group, and a halogen atom.
The alkoxy group usually has 1 or more carbon atoms, usually 6 or less, preferably 3 or less. Examples of the group that may be substituted with the alkoxy group include an alkoxy group, a hydroxyl group, and a halogen atom.

The amino group is represented by NH ₂ , NHR ⁶¹ or NR ⁶² R ⁶³ , and R ^{61 to} R ⁶³ are each independently an alkyl group which may have a substituent or an optionally substituted phenyl. Represents a group. The alkyl group represented by R ^{61 to} R ⁶³ has usually 1 or more, usually 4 or less, preferably 2 or less carbon atoms. Examples of the group that may be substituted with an alkyl group and a phenyl group include an alkoxy group, a hydroxyl group, a sulfo group, a carboxy group, and a halogen atom.

The amide group is represented by NH—COR ⁶⁴ , and R ⁶⁴ represents an alkyl group which may have a substituent or a phenyl group which may have a substituent. The alkyl group represented by R ⁶⁴ has usually 1 or more, usually 4 or less, preferably 2 or less carbon atoms. Examples of the group that may be substituted with an alkyl group and a phenyl group include an alkoxy group, a hydroxyl group, a sulfo group, a carboxy group, and a halogen atom.

p shows the integer of 0-2.
Of these, those in which Y is bonded to ring A and ring D are preferred.

  The molecular weight of the azo dye skeleton is usually 200 or more, particularly 350 or more, and the upper limit is usually 5000 or less, particularly 3500 or less.

  Examples of the condensed polycyclic dye skeleton include the following.

  Of these, a skeleton represented by the general formula (3), a perinone skeleton, a dioxazine skeleton, a skeleton represented by the general formula (5), an anthraquinone skeleton, and the like are preferable, and particularly represented by the general formulas (3) and (4). The skeleton represented by formula (5) and an anthraquinone skeleton are preferred.

  These condensed polycyclic skeletons have a substituted amino group such as a hydroxyl group, an amino group, an alkylamino group, and an arylamino group, a substituent such as an alkoxy group, a nitro group, a sulfo group, a carboxy group, and a halogen atom. Also good.

In the formula, each of R ^{31 to} R ³⁸ may have a hydrogen atom, an alkoxy group that may have a substituent, a hydroxyl group, a nitro group, a sulfo group, a carboxy group, a halogen atom, or a substituent. A group selected from the group consisting of amino groups. Preferably, they are a hydrogen atom, an alkoxy group that may have a substituent, a halogen atom, and an amino group that may have a substituent. Each of the sulfo group and the carboxy group may be a salt such as Li, Na, K, NH ₄ or the like.

The alkoxy group usually has 1 or more carbon atoms, usually 4 or less, and preferably 2 or less. Examples of the group that may be substituted on the alkoxy group include an alkoxy group and a halogen atom.
The amino group is represented by NH ₂ , NHR ⁷¹ or NR ⁷² R ⁷³ , and each of R ^{71 to} R ⁷³ may independently have an alkyl group or a substituent that may have a substituent. Represents a phenyl group. The alkyl group represented by R ^{71 to} R ⁷³ has usually 1 or more, usually 4 or less, preferably 2 or less carbon atoms. Examples of the group that may be substituted with an alkyl group and a phenyl group include an alkoxy group, a hydroxyl group, a sulfo group, a carboxy group, and a halogen atom.
In the general formula (3), a bond extending from nitrogen bonds to Y.

In the formula, each of R ^{41 to} R ⁴⁴ may have a hydrogen atom, an alkoxy group that may have a substituent, a hydroxyl group, a nitro group, a sulfo group, a carboxy group, a halogen atom, or a substituent. A group selected from the group consisting of amino groups. Preferably, they are a hydrogen atom, an alkoxy group that may have a substituent, a halogen atom, and an amino group that may have a substituent. Each of the sulfo group and the carboxy group may be a salt such as Li, Na, K, NH ₄ or the like.

The alkoxy group usually has 1 or more carbon atoms, usually 4 or less, and preferably 2 or less. Examples of the group that may be substituted on the alkoxy group include an alkoxy group and a halogen atom.
The amino group is represented by either NH ₂ , NHR ⁸¹ or NR ⁸² R ⁸³ , and R ^{81 to} R ⁸³ each independently may have an alkyl group or a substituent which may have a substituent. Represents a good phenyl group. The alkyl group represented by R ^{81 to} R ⁸³ has usually 1 or more, usually 4 or less, preferably 2 or less carbon atoms. Examples of the group that may be substituted with an alkyl group and a phenyl group include an alkoxy group, a hydroxyl group, a sulfo group, a carboxy group, and a halogen atom.
In the general formula (4), a bond extending from nitrogen bonds to Y.

In the formula, R ⁵¹ has an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a hydroxyl group, a nitro group, a sulfo group, a carboxy group, a halogen atom, and a substituent. It represents what was chosen from the group which consists of the amino group which may have, the amide group which may have a substituent, and a cyano group. Each of the sulfo group and the carboxy group may be a salt such as Li, Na, K, NH ₄ or the like.

The alkyl group usually has 1 or more carbon atoms, usually 6 or less, and preferably 4 or less. Examples of the group that may be substituted with an alkyl group include an alkoxy group, a hydroxyl group, an amino group, and a halogen atom.
The alkoxy group usually has 1 or more carbon atoms, usually 6 or less, preferably 4 or less. Examples of the group that may be substituted on the alkoxy group include an alkoxy group, a hydroxyl group, an amino group, and a halogen atom.
t is an integer of usually 0 or more, usually 6 or less, preferably 4 or less.

  The number of carbon atoms in the condensed polycyclic dye skeleton is preferably 8 or more, particularly 12 or more. The upper limit is preferably 60 or less, particularly 40 or less. The molecular weight of the condensed polycyclic dye skeleton may be 300 or more, and preferably 400 or more. The upper limit is preferably 3000 or less, particularly 2000 or less.

  In general formula (1), n represents an integer of 2 or more. The upper limit is preferably 6 or less, particularly 4 or less. Among these, a dye having n of 2 is preferable because it tends to have high dichroism.

Y represents a direct bond, O, S, NH, or NCH ₃ . Of these, a direct bond, O, and NH are preferable.
Z is a direct bond, an optionally substituted alkylene group having 1 to 10 carbon atoms, or an optionally substituted (—CH ₂ CH ₂ O—) _m group (m is 1 to 4). Or an optionally substituted (—CH ₂ CH ₂ O—) _{m ′} (—CH ₂ —) _{m ″} group (m ′ is an integer of 1 to 4, m ″ is Represents an integer of 1 to 4). In these formulas, the left end is bonded to the dye skeleton X via Y, and the right end is bonded to the nitrogen atom bonded to the triazine ring.
Examples of the substituent that these linking groups may have include a halogen atom, a hydroxyl group, an amino group, a methyl group, and a methoxy group.

Z preferably has a lower degree of freedom of substituents from the viewpoint of maintaining the flatness of the entire dye, and is a direct bond or an alkylene group having 1 to 4 carbon atoms and a (—CH ₂ CH ₂ O—) _m group. In this case, m is preferably 1 to 2, and if it is a (—CH ₂ CH ₂ O—) _{m ′} (—CH ₂ —) _{m ″} group, m ′ is preferably 1 to 2, and m ″ is preferably 1 to 4. When Z is not a direct bond, the preferred molecular weight of the group represented by Z is 150 or less, more preferably 90 or less.

Ar ¹ and Ar ² each represent an aromatic hydrocarbon group that may have a substituent or an aromatic heterocyclic group that may have a substituent.
As an aromatic hydrocarbon group, a C6-C14 thing is preferable and a phenyl group, a naphthyl group, and an anthryl group are mentioned. Of these, a phenyl group is preferred.

Examples of the substituent that the aromatic hydrocarbon group may have include a water-soluble group such as a sulfo group, a carboxy group, a phosphate group, a hydroxyl group, and an amino group, a halogen atom, a nitro group, a methyl group, a methoxy group, and an alkyl group. An amino group, a dialkylamino group, an amide group, etc. are mentioned. The sulfo group, carboxy group, and phosphate group may each be a salt such as Li, Na, K, NH ₄ or the like.

  The aromatic heterocyclic group is preferably a monocyclic ring or a bicyclic to tricyclic heterocyclic ring. Examples of elements constituting the ring other than carbon include nitrogen, sulfur, and oxygen. When the aromatic heterocyclic group has a plurality of elements constituting a ring other than carbon, these may be the same as or different from each other. Examples of the aromatic heterocyclic group include a pyridyl group, a furyl group, a pyrrolyl group, a thiophenyl group, and a quinolyl group. Of these, a 5- or 6-membered monocycle such as a pyridyl group, a furyl group, or a thiophenyl group is preferred.

Examples of the substituent that the aromatic heterocyclic group may have include a water-soluble group such as a sulfo group, a carboxy group, a phosphate group, a hydroxyl group, and an amino group, a halogen atom, a nitro group, a methyl group, a methoxy group, and an alkyl group. An amino group, a dialkylamino group, an amide group, etc. are mentioned. The sulfo group, carboxy group, and phosphate group may each be a salt such as Li, Na, K, NH ₄ or the like.

Ar ¹ and Ar ² are each preferably an aromatic hydrocarbon group, and more preferably a phenyl group. In addition, one or both of Ar ¹ and Ar ² are substituted with one or more water-soluble groups such as a sulfo group, a carboxy group, a phosphate group, a hydroxyl group, and an amino group so that the dye is dissolved in water. It is more preferable that Ar ¹ and Ar ² each have one or more substituted sulfo groups.

The molecular weights of Ar ¹ and Ar ² are preferably 65 or more and 500 or less, more preferably 70 or more and 250 or less, respectively, with the substituted group in the form of a free acid. When the upper limit is exceeded, there is a possibility that the solubility of the dye is lowered and the association of the dye is inhibited.

  The molecular weight of the following partial structure (1 ′) in the general formula (1) is preferably 330 or more, more preferably 380 or more, preferably 800 or less, and 650 or less when the substituted group is in the form of a free acid. More preferred. If the upper limit is exceeded, the association of the dyes is inhibited due to steric hindrance of the substituent, and if the lower limit is not reached, there is no soluble group sufficient to dissolve the dyes, so the solubility may be insufficient.

  When X is an azo dye skeleton, the molecular weight of the dye represented by the general formula (1) is preferably 800 or more, more preferably 1000 or more in the form of a free acid. Further, the upper limit is preferably 7000 or less, particularly preferably 6000 or less. Further, when X has a condensed polycyclic dye skeleton, the free acid form is preferably 950 or more, more preferably 1100 or more. The upper limit is preferably 5400 or less, particularly 4000 or less. If the molecular weight is too large, there is a risk that the color developability decreases, the steric hindrance of the substituent or the association of the dye molecule decreases due to an increase in the soluble group. There is a risk of shortage.

  The dye represented by the general formula (1) is dissolved or dispersed as a fine crystal in a solvent and forms an associated state such as a lyotropic liquid crystal state in a solution. It is preferably used as a dye for an anisotropic dye film produced by the method.

  The dye represented by the general formula (1) has a solubility in water of preferably 1% by weight or more, preferably 3% by weight or more at room temperature and normal pressure, specifically at 25 ° C. and 1 atm. More preferred. Further, the upper limit is preferably 50% by weight or less, particularly preferably 30% by weight or less. When the anisotropic dye film is produced, the dye is used after being dissolved in a solvent such as water. Therefore, if the solubility of the dye in water is too low, it is difficult to form the anisotropic dye film. Further, from the viewpoint of forming a favorable association state of the dye, it is preferable that the solubility in water is not too high.

Examples of the synthesis method of the dye represented by the general formula (1) include the following methods (A) and (B). The reaction conditions may be carried out according to a conventional method (for example, the method described on pages 802 to 803 of Yutaka Hosoda "Dye Chemistry" (November 25, 1957, Gihodo)).
(A): A dye having a dye skeleton X substituted with an amino group, a compound represented by Ar ¹ NH ₂ , a compound represented by Ar ² NH ₂ , and cyanuric chloride are reacted to form a compound represented by the general formula (1) Synthesize the dyes represented.
(B): A compound having an amino group, a compound represented by Ar ¹ NH ₂ or a compound represented by Ar ² NH ₂ and cyanuric chloride are reacted to synthesize a compound corresponding to the partial structure (1 ′). This is reacted with a dye having the dye skeleton X to synthesize a dye represented by the general formula (1).

  The following are mentioned as such a pigment | dye.

  The method of forming the anisotropic dye film is not particularly limited. First, the dye represented by the general formula (1) and additives or other dyes added as necessary are dissolved or finely dispersed in a solvent. A composition for an isotropic dye film is obtained. The dye represented by the general formula (1) forms a state of forming an aggregate due to a good intermolecular interaction such as a lyotropic liquid crystal state together with an additive in the composition for an anisotropic dye film. An anisotropic dye film can be obtained by coating on a substrate, applying shearing force to orient the dye in a certain direction, and then drying.

  Any solvent may be used as long as it can dissolve or finely disperse the dye, additive, and the like represented by the general formula (1). Among these, from the viewpoint of production safety, it is preferable to use water or a mixture of water and a water-miscible organic solvent.

  Specific examples of water-miscible organic solvents include alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, ethers such as 1,2-dimethoxyethane and tetrahydrofuran, glycols such as ethylene glycol and diethylene glycol, and methyl cellosolve. And cellosolves such as ethyl cellosolve. These organic solvents may be used alone or in combination of two or more.

  The ratio of the dye to the solvent is preferably 0.1% by weight or more from the viewpoint of formation of aggregates and operability of solution coating. In particular, it is particularly preferably 0.5% by weight or more. Further, the upper limit is preferably 50% by weight or less, particularly preferably 35% by weight or less.

  In order to improve the wettability and coating property to the substrate, the anisotropic dye film composition is known as described in surfactants and “Additive for coating”, Edited by J. Bieleman, Willey-VCH (2000). Additives such as these compounds may be included. As the surfactant, any of anionic, cationic and nonionic can be used. The proportion of the surfactant in the composition for anisotropic dye film is usually 0.05% by weight or more, and the upper limit is usually 8% by weight or less. When the amount of the surfactant is too small, the effect of improving the wettability and the coating property cannot be obtained, and when the amount is too large, the orientation of the dye molecules may be inhibited.

  The pH of the composition for anisotropic dye film thus obtained is usually about 4 to 10. Moreover, the composition for anisotropic pigment | dye films may contain pigment | dyes other than the pigment | dye represented by General formula (1) in the range which does not impair the effect of this invention. By including other dyes, the color tone of the anisotropic dye film can be improved.

The anisotropic dye film can be usually prepared by applying a composition for anisotropic dye film to a substrate.
As the substrate, a transparent substrate 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.
On the surface of the substrate, in order to control the orientation direction of the dye molecules in the anisotropic dye film composition, “Liquid Crystal Handbook” (Maruzen Co., Ltd., issued on October 30, 2000), pages 226 to 239. You may form an orientation processing layer by the well-known method as described in a page.

  As a method for applying the composition for the anisotropic dye film on the substrate, a conventionally known method may be used. For example, Yuji Harasaki “Coating Engineering” (Asakura Shoten Co., Ltd., issued 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. And spin coating, spray coating, bar coating, roll coating, blade coating, free span coating, and die coating. The temperature at the time of application is usually 0 to 80 ° C., and the humidity is usually about 10 to 80% RH.

  By applying a shearing force to the dye in the anisotropic dye film composition coated on the substrate, the dye is oriented in a certain 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 coating film may be dried by a conventionally known method. The drying temperature is usually 0 ° C. or higher, preferably 10 ° C. or higher, and the upper limit is usually 120 ° C. or lower, preferably 110 ° C. or lower. . Further, the humidity during drying is usually 10 RH% or more, preferably 30 RH% or more, and the upper limit is usually about 80 RH% or less.

The thickness of the anisotropic dye film thus obtained is usually 50 nm or more and preferably 100 nm or more. The upper limit is usually 50 μm or less, preferably 1 μm or less.
The transmittance of the anisotropic dye film in the visible light wavelength region is preferably 25% or more. The higher the transmittance, the better, and it is preferably 35% or more, particularly 40% or more. Most preferably, it is 44% or more. When the transmittance is low, it is difficult to use as a polarizer for a display element, particularly a color display element.

A protective layer may be provided on the surface of the anisotropic dye film thus formed on the substrate.
An example of the protective layer is a transparent polymer film. The protective layer can be formed by laminating a film made of a resin such as triacetate, acrylic resin, polyester resin, triacetyl cellulose, or urethane resin on the surface of the anisotropic dye film using an adhesive or the like.

  The anisotropic dye film has anisotropy in electromagnetic properties in any two directions selected from a total of three directions in a three-dimensional coordinate system of the film thickness direction and any two orthogonal in-plane directions. It is a film containing a pigment. 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, and a conductive anisotropic film.

  In the present invention, different properties having refractive index anisotropy, conduction anisotropy, light absorption anisotropy, and the like are selected by appropriately selecting the production method, the type of substrate, the composition of the anisotropic dye film composition, and the like. An isotropic membrane can be produced. In particular, the anisotropic dye film containing the dye according to the present invention is suitably used as a polarizing film (film having anisotropy of light absorption) and a conductive anisotropic film.

  As an anisotropic dye film, it can be used as a polarizing film that gives linearly polarized light, circularly polarized light, elliptically polarized light, etc., which is suitable as a polarizing film (polarizing element) for various display elements such as LCD and OLED. Used. In this case, an anisotropic dye film may be formed by directly applying the composition for an anisotropic dye film to an electrode substrate or the like constituting these display elements and drying, or an anisotropic dye film may be formed. The substrate thus prepared may be used as a constituent member of these display elements.

The polarizing element of the present invention uses the above-described anisotropic dye film of the present invention, but it may be a polarizing element consisting only of an anisotropic dye film, or an anisotropic dye film on a substrate. It may be a polarizing element. A polarizing element having an anisotropic dye film on a substrate is called a polarizing element including a base material.
When the anisotropic dye film of the present invention is formed on a substrate and used as a polarizing element, the formed anisotropic dye film itself may be used. In addition to the protective layer as described above, an adhesive layer Or a layer having an optical function such as an antireflection layer, an alignment film, a function as a retardation film, a function as a brightness enhancement film, a function as a reflection film, a function as a transflective film, a function as a diffusion film, etc. Layers having various functions may be laminated by a wet film formation method or the like, and used as a laminate.

These layers having optical functions 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 Japanese Patent No. 2841377, Japanese Patent No. 3094113, or a process described in Japanese Patent No. 3168850. Can be formed.

In addition, 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, JP 2002-169025 A or JP 2003-29030 A, 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 dye film using the dye according to the present invention can be directly formed on a high heat resistant substrate such as glass, and a liquid crystal display can be obtained from the point that a high heat resistant polarizing element can be obtained. In addition to organic EL displays, it can be suitably used 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 examples, the dichroic ratio (D) was calculated by the following equation after measuring the transmittance of the anisotropic organic film with a spectrophotometer in which an iodine polarizing element was arranged in the incident optical system.
Dichroic ratio (D) = Az / Ay
Az = -log (Tz)
Ay = -log (Ty)
Tz: transmittance for polarized light in the absorption axis direction of the organic film
Ty: transmittance for polarized light in the direction of the polarization axis of the organic film

<Example 1>
37 parts by weight of disodium 4,4 ′-[(6-chloro-1,3,5-triazine-2,4-diyl) diimino] bisbenzenesulfonate synthesized from 4-aminobenzenesulfonic acid and cyanuric chloride Sodium hydroxide was dissolved in 17 parts by weight of N, N′-bis (2-aminoethyl) perylene-3,4,9,10-bis (dicarboximide) in 200 parts by weight of water and heated to 70 ° C. At pH = 8 and reacted for 40 hours. 50 parts by weight of sodium chloride was added to the system, and the dye deposited by suction filtration was taken out, washed with water, and then crystallized with water-isopropanol to obtain dye I.

  The anisotropic dye film composition containing Dye I and the anisotropic dye film were prepared by the following method. That is, 10 parts by weight of the dye I having the above composition was added to 90 parts by weight of water, dissolved by stirring, and then filtered to obtain an aqueous dye solution (an anisotropic dye film composition). When this dye aqueous solution was dropped on a slide glass and observed under a polarizing microscope, it was confirmed to be in a lyotropic liquid crystal state.

After applying the dye aqueous solution to a slide glass (Matsunami Glass Industries slide glass white edge polishing frost No. 1) with a bar coater (Tester Sangyo Co., Ltd. No. 2), drying at room temperature makes it anisotropic. A dye film was obtained.
As confirmation of the anisotropy of the obtained dye film, the dichroic ratio was measured and found to be 3 at the maximum absorption wavelength of 515 nm, confirming the absorption anisotropy.

<Example 2>
4,4 ′-[(6-Chloro-1,3,5-triazine-2,4-diyl) diimino] bisbenzenesulfonic acid synthesized from 55 parts by weight of 4-aminobenzenesulfonic acid and 30 parts by weight of cyanuric chloride Dissolve 14 parts by weight of dilithium and N, N′-bis (2-aminoethyl) -1,4-diaminoanthraquinone in 500 parts by weight of water, and maintain at pH = 8 with lithium hydroxide while heating to 80 ° C. For 40 hours. Hydrochloric acid was added to the system, and the dye deposited by suction filtration was taken out, washed with water, neutralized with lithium hydroxide, and then crystallized with water-isopropanol to obtain dye II.

The anisotropic dye film composition containing Dye II and the anisotropic dye film were prepared by the following method. That is, 10 parts by weight of the dye I having the above composition was added to 90 parts by weight of water, dissolved by stirring, and then filtered to obtain an aqueous dye solution (an anisotropic dye film composition).
After applying the dye aqueous solution to a slide glass (Matsunami Glass Industries slide glass white edge polishing frost No. 1) with a bar coater (Tester Sangyo Co., Ltd. No. 2), drying at room temperature makes it anisotropic. A dye film was obtained.
As confirmation of the anisotropy of the obtained dye film, the dichroic ratio was measured and found to be 4 at the maximum absorption wavelength of 605 nm, confirming the absorption anisotropy.

Claims (7)

A dye for anisotropic dye film represented by the following general formula (1).

(In the formula, X represents a dye skeleton, n represents an integer of 2 or more, Y represents a direct bond, O, S, NH, NCH ₃ , and Z may have a direct bond or a substituent. alkylene group having 1 to 10 carbon atoms, which may have an optionally substituted (where m represents an integer of _{1~4) (-CH 2 CH 2 O-} ) m group or a substituted group Represents a good (—CH ₂ CH ₂ O—) _{m ′} (—CH ₂ —) _{m ″} group (where m ′ represents an integer of 1 to 4 and m ″ represents an integer of 1 to 4), Ar ¹ and Ar ² each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, and a plurality of which are included in one molecule. Y, Z, Ar ¹ and Ar ² may be the same or different.) The Ar ¹ and Ar ² are both an aromatic hydrocarbon group substituted with a sulfo group or a salt thereof or an aromatic heterocyclic group substituted with a sulfo group or a salt thereof. Dye for anisotropic dye film.   3. The dye for anisotropic dye film according to claim 1, wherein, in the general formula (1), X is a condensed polycyclic dye skeleton or an azo dye skeleton. 3. The dye for anisotropic dye film according to claim 1, wherein in the general formula (1), X is represented by any one of the following general formulas (2) to (5).

(In the formula, ring A to ring D each independently represent a benzene ring or a naphthalene ring. P represents an integer of 0 to 2. Note that these rings may have a substituent. Alkyl group, optionally substituted alkoxy group, hydroxyl group, nitro group, sulfo group, carboxy group, halogen atom, optionally substituted amino group, optionally substituted (It may have a substituent selected from the group consisting of an amide group and a cyano group.)

(In the formula, each of R ^{31 to} R ³⁸ may have a hydrogen atom, an alkoxy group which may have a substituent, a hydroxyl group, a nitro group, a sulfo group, a carboxy group, a halogen atom, or a substituent. Represents one selected from the group consisting of good amino groups.)

(In the formula, each of R ^{41 to} R ⁴⁴ may have a hydrogen atom, an alkoxy group which may have a substituent, a hydroxyl group, a nitro group, a sulfo group, a carboxy group, a halogen atom, or a substituent. Represents one selected from the group consisting of good amino groups.)

(In the formula, R ⁵¹ has an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a hydroxyl group, a nitro group, a sulfo group, a carboxy group, a halogen atom, and a substituent. Represents an amino group that may be substituted, an amide group that may have a substituent, and a cyano group, and t is an integer of 0 to 6. When t is 2 or more. The plurality of R ⁵¹ may be the same or different.)   An anisotropic dye film composition comprising the dye for an anisotropic dye film according to any one of claims 1 to 4 and a solvent.   An anisotropic dye film comprising the dye for anisotropic dye film according to claim 1.   A polarizing element comprising the anisotropic dye film according to claim 6.