JP6862365B2 - Azo compounds, polarizing elements and polarizing plates using them, and display devices - Google Patents

Description

The present invention relates to a novel azo compound, a polarizing element and a polarizing plate having a high degree of polarization using the azo compound, and a display device.

The polarizing element is generally manufactured by adsorbing and orienting iodine or a dichroic dye, which is a dichroic dye, on a polyvinyl alcohol resin film. A protective film made of triacetyl cellulose or the like is attached to at least one surface of the polarizing element via an adhesive layer to form a polarizing plate. Polarizing plates are used in display devices and the like. A polarizing plate using iodine as a dichroic dye is called an iodine-based polarizing plate, while a polarizing plate using a dichroic dye as a dichroic dye is called a dye-based polarizing plate. Of these, dye-based polarizing plates are characterized by having high heat resistance, high humidity heat durability, and high stability, and high color selectivity due to the blending of dichroic dyes.

Patent Documents 1 to 4 and Non-Patent Documents 1 and 2 disclose dye-based polarizing elements containing an azo compound.

Japanese Unexamined Patent Publication No. 11-218611 Japanese Patent No. 4162334 Japanese Patent No. 4360100 Japanese Unexamined Patent Publication No. 2004-075719

Yutaka Hosoda, "Dye Chemistry", Gihodo Publishing Co., Ltd., 1957, p. 621 Supervised by Masahiro Irie, "Application of Functional Dyes" (1st edition), CMC Publishing Co., Ltd., June 2002, p. 98-104

However, the conventional polarizing elements containing azo compounds described in Patent Documents 1 to 4 and Non-Patent Documents 1 and 2 have poor polarization performance and contrast, and can sufficiently meet the demands for recent high-definition displays. I wasn't.

One of an object of the present invention is to provide a polarizing element and a polarizing plate having excellent polarization performance and contrast, a display device having excellent contrast, and a novel azo compound that can be used for them.

As a result of diligent studies to solve the above problems, the present inventors have found a novel azo compound that can be used as a dichroic dye constituting a polarizing element and a polarizing plate, and have been excellent by using the azo compound. We have found that a polarizing element and a polarizing plate having polarization performance and contrast, and a display device having excellent contrast can be realized, and have completed the present invention.

（式中、Ａｂ_１は置換基を有するフェニル基、又は置換基を有するナフチル基を表し、Ｒｂ_１〜Ｒｂ_５はそれぞれ独立に、水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基、スルホ基、又はスルホ基を有する炭素数１〜４のアルコキシ基を表し、Ｘｂ_１は置換基を有していてもよいアミノ基、置換基を有していてもよいフェニルアミノ基、置換基を有していてもよいベンゾイルアミノ基、置換基を有していてもよいフェニルアゾ基、又は置換基を有していてもよいナフトトリアゾール基を表す。）
で表されるアゾ化合物又はその塩であることを特徴とするアゾ化合物、
（２）（１）項に記載のアゾ化合物であって、下記一般式（２）

（式中、Ａｂ_１は、スルホ基、カルボキシ基、炭素数１〜４のアルキル基、及び炭素数１〜４のアルコキシ基からなる群より選択される１個もしくは２個の置換基を有するフェニル基、又はスルホ基、ヒドロキシ基、及びスルホ基を有する炭素数１〜４のアルコキシ基からなる群より選択される２個もしくは３個の置換基を有するナフチル基を表し、Ｒｂ_１〜Ｒｂ_５はそれぞれ独立に、水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基、又はスルホ基を有する炭素数１〜４のアルコキシ基を表し、Ｘｂ_１は、メチル基、メトキシ基、スルホ基、アミノ基、及び炭素数１〜４のアルキルアミノ基からなる群より選択される１個もしくは２個の置換基を有していてもよいフェニルアミノ基、ヒドロキシ基、アミノ基、及びカルボキシエチルアミノ基からなる群より選択される１個の置換基を有していてもよいベンゾイルアミノ基、ヒドロキシ基、炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基、アミノ基、及びカルボキシエチルアミノ基からなる群より選択される１〜３個の置換基を有していてもよいフェニルアゾ基、又は１個もしくは２個のスルホ基で置換されたナフトトリアゾール基を表す。）で表されるアゾ化合物又はその塩であることを特徴とするアゾ化合物、
（３）（１）項又は（２）項に記載のアゾ化合物であって、前記一般式（１）又は（２）中のＸｂ_１が、メチル基、メトキシ基、スルホ基、アミノ基、及び炭素数１〜４のアルキルアミノ基からなる群より選択される１個又は２個の置換基を有していてもよいフェニルアミノ基であることを特徴とするアゾ化合物、
（４）基材と、（１）〜（３）項のいずれか１項に記載のアゾ化合物とを含むことを特徴とする偏光素子、
（５）（４）項に記載の偏光素子であって、下記一般式（３）

（式中、Ａｒ_１は置換基を有するフェニル基、又は置換基を有するナフチル基を表し、Ｒｒ_１〜Ｒｒ_６はそれぞれ独立に、水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基、又はスルホ基を有する炭素数１〜４のアルコキシ基を表し、Ｘｒ_１は置換基を有していてもよいアミノ基、置換基を有していてもよいフェニルアミノ基、置換基を有していてもよいベンゾイルアミノ基、置換基を有していてもよいフェニルアゾ基、又は置換基を有していてもよいナフトトリアゾール基を表し、ｍ及びｎはそれぞれ独立に、０又は１を示す。）で表されるアゾ化合物又はその塩をさらに含むことを特徴とする偏光素子、
（６）（４）又は（５）項に記載の偏光素子であって、下記一般式（４）

（式中、Ａｙ_１は、スルホ基、カルボキシ基、ヒドロキシ基、炭素数１〜４のアルキル基、又は炭素数１〜４のアルコキシ基を表し、Ｒｙ_１〜Ｒｙ_４はそれぞれ独立に、水素原子、スルホ基、炭素数１〜４のアルキル基、又は炭素数１〜４のアルコキシ基を表し、ｐは１〜３の整数を示す。）
で表されるアゾ化合物又はその塩をさらに含むことを特徴とする偏光素子、
（７）（５）項に記載の偏光素子であって、前記一般式（３）で表されるアゾ化合物又はその塩が、下記一般式（５）

（式中、Ａｒ_１は、スルホ基、カルボキシ基、炭素数１〜４のアルキル基、及び炭素数１〜４のアルコキシ基からなる群より選択される１個もしくは２個の置換基を有するフェニル基、又はスルホ基、ヒドロキシ基、及びスルホ基を有する炭素数１〜４のアルコキシ基からなる群より選択される２個もしくは３個の置換基を有するナフチル基を表し、Ｒｒ_１〜Ｒｒ_６はそれぞれ独立に、水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基、又はスルホ基を有する炭素数１〜４のアルコキシ基を表し、Ｘｒ_１は、メチル基、メトキシ基、スルホ基、アミノ基、及び炭素数１〜４のアルキルアミノ基からなる群より選択される１個もしくは２個の置換基を有していてもよいフェニルアミノ基、ヒドロキシ基、アミノ基、及びカルボキシエチルアミノ基からなる群より選択される１個の置換基を有していてもよいベンゾイルアミノ基、ヒドロキシ基、炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基、アミノ基、及びカルボキシエチルアミノ基からなる群より選択される１〜３個の置換基を有していてもよいフェニルアゾ基、又は１個もしくは２個のスルホ基で置換されたナフトトリアゾール基を表し、ｍ及びｎはそれぞれ独立に、０又は１を示す。）で表されるアゾ化合物又はその塩であることを特徴とする偏光素子、
（８）（５）又は（７）項に記載の偏光素子であって、前記一般式（３）又は（５）中のＲｒ_５及びＲｒ_６は、一方が炭素数１〜４のアルコキシ基であり、他方が炭素数１〜４のアルキル基又は炭素数１〜４のアルコキシ基であることを特徴とする偏光素子、
（９）（５）又は（７）項に記載の偏光素子であって、前記一般式（３）又は（５）中のＸｒ_１が、メチル基、メトキシ基、スルホ基、アミノ基、及び炭素数１〜４のアルキルアミノ基からなる群より選択される１個もしくは２個の置換基を有していてもよいフェニルアミノ基、又はヒドロキシ基、アミノ基、及びカルボキシエチルアミノ基からなる群より選択される１個の置換基を有していてもよいベンゾイルアミノ基であることを特徴とする偏光素子、
（１０）（６）項に記載の偏光素子であって、一般式（４）中のＡｙ_１が、カルボキシ基又はスルホ基であることを特徴とする偏光素子、
（１１）（４）〜（１０）項のいずれか１項に記載の偏光素子であって、前記基材が、ポリビニルアルコール又はその誘導体からなるフィルムであることを特徴とする偏光素子、
（１２）（４）〜（１１）項のいずれか１項に記載の偏光素子と、前記偏光素子の少なくとも片面に設けられた透明保護層とを備えることを特徴とする偏光板、
（１３）（４）〜（１１）項のいずれか１項に記載の偏光素子、又は（１２）項に記載の偏光板を備えることを特徴とする表示装置、
に関する。That is, the present invention
(1) The following general formula (1)

(In the formula, Ab ₁ represents a phenyl group having a substituent or a naphthyl group having a substituent, and Rb _{1 to Rb 5} independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and 1 to 1 carbon atoms. Represents an alkoxy group of 4, a sulfo group, or an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and Xb ₁ is an amino group which may have a substituent or a phenylamino which may have a substituent. Represents a group, a benzoylamino group which may have a substituent, a phenylazo group which may have a substituent, or a naphthotriazole group which may have a substituent.)
An azo compound represented by, or a salt thereof.
(2) The azo compound according to item (1), which has the following general formula (2).

(In the formula, Ab ₁ is a phenyl having one or two substituents selected from the group consisting of a sulfo group, a carboxy group, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. Represents a naphthyl group having 2 or 3 substituents selected from the group consisting of a group or a sulfo group, a hydroxy group, and an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and Rb _{1 to Rb 5 represent.} Each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and Xb ₁ is a methyl group or a methoxy group. , A phenylamino group, a hydroxy group, an amino group, which may have one or two substituents selected from the group consisting of a sulfo group, an amino group, and an alkylamino group having 1 to 4 carbon atoms. A benzoylamino group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an amino group, which may have one substituent selected from the group consisting of a carboxyethylamino group. , And a phenylazo group which may have 1 to 3 substituents selected from the group consisting of carboxyethylamino groups, or a naphthotriazole group substituted with 1 or 2 sulfo groups.) An azo compound represented by, or a salt thereof.
(3) The azo compound according to (1) or (2), wherein Xb ₁ in the general formula (1) or (2) is a methyl group, a methoxy group, a sulfo group, an amino group, and An azo compound, which is a phenylamino group which may have one or two substituents selected from the group consisting of alkylamino groups having 1 to 4 carbon atoms.
(4) A polarizing element comprising a base material and the azo compound according to any one of (1) to (3).
(5) The polarizing element according to item (4), which has the following general formula (3).

(In the formula, Ar ₁ represents a phenyl group having a substituent or a naphthyl group having a substituent, and Rr _{1 to Rr 6} independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and 1 to 1 carbon atoms. Represents an alkoxy group of 4 or an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and Xr ₁ is an amino group which may have a substituent, a phenylamino group which may have a substituent, or a substituent. It represents a benzoylamino group which may have a group, a phenylazo group which may have a substituent, or a naphthotriazole group which may have a substituent, and m and n are independently 0 or n, respectively. A polarizing element, which further contains an azo compound represented by 1) or a salt thereof.
(6) The polarizing element according to item (4) or (5), which has the following general formula (4).

(In the formula, Ay ₁ represents a sulfo group, a carboxy group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and Ry _{1 to Ry 4} are independent hydrogen atoms. , A sulfo group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and p represents an integer of 1 to 3).
A polarizing device, which further contains an azo compound represented by (1) or a salt thereof.
(7) The polarizing element according to item (5), wherein the azo compound represented by the general formula (3) or a salt thereof is the following general formula (5).

(In the formula, Ar ₁ is a phenyl having one or two substituents selected from the group consisting of a sulfo group, a carboxy group, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. Represents a naphthyl group having 2 or 3 substituents selected from the group consisting of a group or a sulfo group, a hydroxy group, and an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and Rr _{1 to Rr 6} are Each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and Xr ₁ is a methyl group or a methoxy group. , A phenylamino group, a hydroxy group, an amino group, which may have one or two substituents selected from the group consisting of a sulfo group, an amino group, and an alkylamino group having 1 to 4 carbon atoms. A benzoylamino group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an amino group, which may have one substituent selected from the group consisting of a carboxyethylamino group. , And a phenylazo group which may have 1 to 3 substituents selected from the group consisting of carboxyethylamino groups, or a naphthotriazole group substituted with 1 or 2 sulfo groups. And n independently represent 0 or 1), respectively.) A polarizing element, characterized in that it is an azo compound or a salt thereof.
(8) The polarizing element according to the item (5) or (7), wherein one of Rr ₅ and Rr ₆ in the general formula (3) or (5) is an alkoxy group having 1 to 4 carbon atoms. A polarizing element, wherein the other is an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms.
(9) In the polarizing element according to (5) or (7), Xr ₁ in the general formula (3) or (5) is a methyl group, a methoxy group, a sulfo group, an amino group, and a carbon. From the group consisting of a phenylamino group which may have one or two substituents selected from the group consisting of the number 1 to 4 alkylamino groups, or the group consisting of a hydroxy group, an amino group, and a carboxyethylamino group. A polarizing element, characterized in that it is a benzoylamino group which may have one substituent of choice.
(10) The polarizing element according to item (6), wherein Ay ₁ in the general formula (4) is a carboxy group or a sulfo group.
(11) The polarizing element according to any one of (4) to (10), wherein the base material is a film made of polyvinyl alcohol or a derivative thereof.
(12) A polarizing plate comprising the polarizing element according to any one of (4) to (11) and a transparent protective layer provided on at least one surface of the polarizing element.
(13) A display device comprising the polarizing element according to any one of (4) to (11) or the polarizing plate according to (12).
Regarding.

According to the present invention, it is possible to provide a polarizing element and a polarizing plate having excellent polarization performance and contrast, a display device having excellent contrast, and a novel azo compound that can be used for them.

で表されるアゾ化合物又はその塩である。本発明のアゾ化合物は、一般的に二色性染料と言われる色素として機能する水溶性染料である。Hereinafter, the present invention will be described in detail.
[New azo compound]
The azo compound of the present invention has the following general formula (1).

It is an azo compound represented by, or a salt thereof. The azo compound of the present invention is a water-soluble dye that functions as a dye generally called a dichroic dye.

In the general formula (1), Ab ₁ represents a phenyl group having a substituent or a naphthyl group having a substituent, and Rb _{1 to Rb 5} independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and carbon. Represents an alkoxy group of number 1 to 4 or an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and Xb ₁ is an amino group or a substituent which may have a substituent (excluding a phenyl group and a benzoyl group). A phenylamino group which may have a substituent, a benzoylamino group which may have a substituent, a phenylazo group which may have a substituent, or a naphthotriazole group which may have a substituent. Represent.

（式中、Ａｂ_１、Ｒｂ_１〜Ｒｂ_５、及びＸｂ_１は、一般式（１）中と同じ意味を表す。）
で表されるアゾ化合物であることが好ましい。これにより、一般式（１）で表されるアゾ化合物を使用した偏光素子の偏光性能をさらに向上させることができる。The azo compound represented by the general formula (1) has the following general formula (2).

(In the formula, Ab ₁ , Rb _{1 to Rb 5} , and Xb ₁ have the same meanings as in the general formula (1).)
It is preferably an azo compound represented by. Thereby, the polarization performance of the polarizing element using the azo compound represented by the general formula (1) can be further improved.

_{Ab 1} in the general formula (1) or (2) represents a phenyl group having a substituent or a naphthyl group having a substituent, but a sulfo group, a carboxy group, an alkyl group having 1 to 4 carbon atoms, and an alkyl group having 1 to 4 carbon atoms. It consists of a phenyl group having one or two substituents selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having a sulfo group, a hydroxy group, and a sulfo group and having 1 to 4 carbon atoms. It is preferably a naphthyl group having 2 or 3 substituents selected from the group.

_{When Ab 1} in the general formula (1) or (2) is a phenyl group having a substituent, it is preferable to have at least one sulfo group or carboxy group as the substituent. When Ab ₁ is a phenyl group having two or more substituents, at least one (some) substituents among those substituents are a sulfo group or a carboxy group, and the other substituent is a sulfo group. Group, carboxy group, alkyl group having 1 to 4 carbon atoms, alkoxy group having 1 to 4 carbon atoms, alkoxy group having 1 to 4 carbon atoms having a sulfo group, nitro group, amino group, acetylamino group, or 1 carbon group It is preferably an alkylamino group of ~ 4. The substituent on the phenyl group is more preferably a sulfo group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group, an amino group, or a carboxy group, and particularly preferably a sulfo group. It is a group, a methyl group, a methoxy group, an ethoxy group, or a carboxy group. The number of substituents on the phenyl group is preferably two. The substitution position of the substituent on the phenyl group is not particularly limited, but when the number of substituents on the phenyl group is 2, a combination of the 2-position and the 4-position is preferable.

_{When Ab 1} in the general formula (1) or (2) is a naphthyl group having a substituent, it is preferable to have at least one sulfo group as the substituent. When Ab ₁ is a naphthyl group having two or more substituents, at least one (some) substituents among those substituents are sulfo groups, and the other substituents are sulfo groups, It is preferably an alkoxy group having 1 to 4 carbon atoms having a hydroxy group, a carboxy group, or a sulfo group. When the number of substituents on the naphthyl group is 2, the combination of the substitution positions of these substituents is a combination of the 4-position and the 8-position, or a combination of the 6-position and the 8-position. Is preferable, and a combination of the 6-position and the 8-position is particularly preferable. When the number of substituents on the naphthyl group is 3, the combination of the substitution positions of these substituents is particularly preferably the combination of the 1-position, the 3-position and the 6-position.

The alkoxy group having a sulfo group and having 1 to 4 carbon atoms as a substituent on the phenyl group or the naphthyl group in Ab _{1 is preferably a linear alkoxy group having a sulfo group and having 1 to 4 carbon atoms.} In the alkoxy group having a sulfo group and having 1 to 4 carbon atoms, the substituent of the sulfo group is preferably an alkoxy group terminal. The alkoxy group having a sulfo group and having 1 to 4 carbon atoms is more preferably a 3-sulfopropoxy group or a 4-sulfobutoxy group, and particularly preferably a 3-sulfopropoxy group.

_{Xb 1} in the general formula (1) or (2) is an amino group which may have a substituent (excluding a phenyl group and a benzoyl group), a phenylamino group which may have a substituent, and a substituent. Represents a benzoylamino group which may have a substituent, a phenylazo group which may have a substituent, or a naphthotriazole group which may have a substituent, but preferably a methyl group, a methoxy group, or a sulfo group. A phenylamino group, a hydroxy group, an amino group, and a carboxyethyl which may have one or two substituents selected from the group consisting of a group, an amino group, and an alkylamino group having 1 to 4 carbon atoms. A benzoylamino group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an amino group, and an amino group, which may have one substituent selected from the group consisting of amino groups. A phenylazo group which may have 1 to 3 substituents selected from the group consisting of carboxyethylamino groups, or a naphthotriazole group substituted with 1 or 2 sulfo groups, more preferably. , A phenylamino group which may have one or two substituents selected from the group consisting of a methyl group, a methoxy group, a sulfo group, an amino group, and an alkylamino group having 1 to 4 carbon atoms, or A benzoylamino group which may have one substituent selected from the group consisting of a hydroxy group, an amino group and a carboxyethylamino group, more preferably a methyl group, a methoxy group, a sulfo group and an amino group. It is a phenylamino group which may have one or two substituents selected from the group consisting of a group and an alkylamino group having 1 to 4 carbon atoms. The substitution position of the substituent is not particularly limited, but when Xb ₁ is a phenylamino group having one substituent, a benzoylamino group having one substituent, or a phenylazo group having one substituent. The p-position is particularly preferable.

_{Rb 1 to Rb 5} in the general formula (1) or (2) each independently have a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a sulfo group having 1 carbon atom. It represents an alkoxy group of ~ 4, preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and more preferably a hydrogen atom, a methyl group, or a methoxy group. is there. In order to further improve the optical characteristics, _{the combination of the replacement positions of Rb 1} and Rb ₂ and the combination of the replacement positions of Rb ₃ and Rb ₄ are independently the combination of the 2-position and the 6-position, 2-position. A combination of positions and 5-positions, or a combination of 3-positions and 5-positions is preferable, and a combination of 2-positions and 5-positions is more preferable. The substitution position of Rb ₅ is preferably 2-position or 3-position, and more preferably 2-position. The combination of the substitution positions of Rb ₁ and Rb ₂ and the combination of the substitution positions of Rb ₃ and Rb ₄ are independent of each other, and when at least one of them is a methoxy group, the combination of the 2-position and the 6-position, 2- A combination of positions and 5-positions, or a combination of 3-positions and 5-positions is preferable, and a combination of 2-positions and 5-positions is more preferable.

The method for producing the azo compound represented by the general formula (1) will be described below. Since the azo compound represented by the general formula (1) can be produced by the same production method as a known production method, the method for producing the azo compound represented by the general formula (1) is described here. It is not limited to the described manufacturing method. For example, the azo compound represented by the general formula (1) can be easily produced by performing known diazotization and coupling according to a usual method for producing an azo dye as described in Non-Patent Document 1.

（式中、Ａｂ_１、Ｒｂ_１、及びＲｂ_２は、前記一般式（１）及び（２）中と同じ意味を表す。）
で表されるモノアゾアミノ化合物を得る。The azo compound represented by the general formula (1) can be produced as follows. First, the following general formula (6)

(In the formula, Ab ₁ , Rb ₁ , and Rb ₂ have the same meanings as in the general formulas (1) and (2).)
The monoazoamino compound represented by is obtained.

（式中、Ｒｂ_１１及びＲｂ_１２は、一方が、スルホ基又はカルボキシ基を表し、他方が、スルホ基、カルボキシ基、炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基、スルホ基を有する炭素数１〜４のアルコキシ基、カルボキシ基、ニトロ基、アミノ基、アセチルアミノ基、又は炭素数１〜４のアルキルアミノ基を表す。）
で表される芳香族アミン類を公知の方法によりスルホアルキル化して得られるスルホアルコキシアニリン酸類をジアゾ化し、下記一般式（８）

（式中、Ｒｂ_１及びＲｂ_２は、前記一般式（１）及び（２）中と同じ意味を表す。）
で表されるアニリン類と１次カップリングさせることによって得られる。 _{When Ab 1} is a phenyl group having at least one sulfo group, the monoazoamino compound represented by the general formula (6) has the following general formula (7).

(In the formula, one of Rb ₁₁ and Rb ₁₂ represents a sulfo group or a carboxy group, and the other represents a sulfo group, a carboxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a sulfo group. Represents an alkoxy group having 1 to 4 carbon atoms, a carboxy group, a nitro group, an amino group, an acetylamino group, or an alkylamino group having 1 to 4 carbon atoms.
The sulfoalkoxyaniline acids obtained by sulfoalkylating the aromatic amines represented by the above by a known method are diazotized and the following general formula (8) is used.

(In the formula, Rb ₁ and Rb ₂ have the same meanings as in the general formulas (1) and (2).)
It is obtained by primary coupling with the anilines represented by.

（式中、Ｒｂ_１３は、水素原子、ヒドロキシ基、カルボキシ基、スルホ基、トシレート化されたヒドロキシ基、アミノ基、置換アミノ基、ニトロ基、置換アミド基、又はスルホ基を有する炭素数１〜４のアルコキシ基を表し、ｑは１〜３の整数を示す。）
で表されるナフチルアミンスルホン酸類、又はアミノナフトールスルホン酸類を公知の方法によりスルホアルキル化して得られるスルホアルコキシナフチルアミンスルホン酸類をジアゾ化し、前記一般式（８）で表されるアニリン類と１次カップリングさせることによって得られる。 _{When Ab 1} is a naphthyl group having at least one sulfo group, the monoazoamino compound represented by the general formula (6) has the following general formula (9).

(In the formula, Rb ₁₃ has 1 to 1 carbon atoms having a hydrogen atom, a hydroxy group, a carboxy group, a sulfo group, a tosylated hydroxy group, an amino group, a substituted amino group, a nitro group, a substituted amide group, or a sulfo group. It represents an alkoxy group of 4, and q represents an integer of 1 to 3).
The naphthylamine sulfonic acid represented by (8) or the sulfoalkoxynaphthylamine sulfonic acid obtained by sulfoalkylating the aminonaphthol sulfonic acid by a known method is diazotized and the primary coupling with the aniline represented by the general formula (8). Obtained by letting.

（式中、Ｒｂ_３及びＲｂ_４は、前記一般式（１）及び一般式（２）中と同じ意味を表す。）
で表されるアニリン類と２次カップリングさせ、下記一般式（１１）

（式中、Ａｂ_１、Ｒｂ_１、Ｒｂ_２、Ｒｂ_３、及びＲｂ_４は、前記一般式（１）及び（２）中と同じ意味を表す。）
で表されるジスアゾアミノ化合物を得る。Next, the monoazoamino compound represented by the general formula (6) is diazotized, and the following general formula (10) is used.

(In the formula, Rb ₃ and Rb ₄ have the same meanings as in the general formula (1) and the general formula (2).)
Secondary coupling with anilines represented by, the following general formula (11)

(In the formula, Ab ₁ , Rb ₁ , Rb ₂ , Rb ₃ , and Rb ₄ have the same meanings as in the general formulas (1) and (2).)
The disuazoamino compound represented by is obtained.

で表されるアニリン類と３次カップリングさせ、下記一般式（１３）

（式中、Ａｂ_１及びＲｂ_１〜Ｒｂ_５は、一般式（１）及び（２）中と同じ意味を表す。）
で表されるトリスアゾアミノ化合物を得る。Next, the diazoamino compound represented by the general formula (11) is diazotized, and the following general formula (12) is used.

The following general formula (13) is used for tertiary coupling with anilines represented by.

(In the formula, Ab ₁ and Rb _{1 to Rb 5} have the same meanings as in the general formulas (1) and (2).)
The trisazoamino compound represented by is obtained.

（式中、Ｘｂ_１は、前記一般式（１）及び（２）中と同じ意味を表す。）
で表されるナフトール類と４次カップリングさせることにより、下記一般式（１５）

（式中、Ａｂ_１、Ｒｂ_１〜Ｒｂ_５、及びＸｂ_１は、前記一般式（１）及び（２）中と同じ意味を表す。）
で表されるテトラアゾ化合物が得られる。Next, the trisazoamino compound represented by the general formula (13) was diazotized by a known method, and the following general formula (14) was used.

(In the formula, Xb ₁ has the same meaning as in the general formulas (1) and (2).)
By quaternary coupling with naphthols represented by, the following general formula (15)

(In the formula, Ab ₁ , Rb _{1 to Rb 5} , and Xb ₁ have the same meanings as in the general formulas (1) and (2).)
The tetraazo compound represented by is obtained.

A copper complex salt compound composed of copper sulfate and at least one selected from the group consisting of aqueous ammonia, aminoalcohol, and hexamethylenetetramine is preferably added to the tetraazo compound represented by the general formula (15). Is subjected to a copperification reaction at 85 ° C. to 95 ° C. to obtain a copper complex-chloride azo compound represented by the general formula (1) or the general formula (2).

The diazotization step in the above synthesis is carried out by a normal method of mixing a nitrite such as sodium nitrite with a mineral acid aqueous solution or suspension of the diazo component such as hydrochloric acid or sulfuric acid, or a neutral or weakly alkaline diazo component. This is done by the reverse method of adding nitrite to the aqueous solution and mixing it with mineral acid. The temperature of diazotization is preferably -10 to 40 ° C. In the coupling step between the diazoized product and anilines, an acidic aqueous solution such as hydrochloric acid or acetic acid is mixed with each of the above diazo solutions (aqueous solution or suspension of the diazoized product), and the temperature is −10 to 40 ° C. and pH 2 It is carried out under acidic conditions of ~ 7.

The monoazoamino compound, disazoamino compound, and trisazoamino compound obtained by coupling can be taken out by filtration or as a solution or suspension as they are, or after being precipitated by acidification or salting out. You can also proceed to the next step. If the diazonium salt is sparingly soluble and is in suspension, it can be filtered and used as a press cake in the next coupling step.

The fourth-order coupling reaction between the diazodized trisazoamino compound represented by the general formula (13) and the naphthols represented by the general formula (14) has a temperature of −10 to 40 ° C. and a pH of 7 to 10. It is carried out under neutral to alkaline conditions. After completion of the reaction, it is precipitated by salting out, filtered and taken out. When purification is required, salting out may be repeated or precipitation may be performed from water using an organic solvent. Examples of the organic solvent used for purification include water-soluble organic solvents such as alcohols such as methanol and ethanol, and ketones such as acetone.

The aromatic represented by the general formula (7), which is a starting material (raw material compound) for synthesizing the azo compound represented by the general formula (1) when _{Ab 1 is a phenyl group having a substituent.} Examples of amines Rb ₁₁ and Rb ₁₂ include a hydrogen atom, a sulfo group, a carboxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms having a sulfo group. , A naphthotriazole group substituted with a sulfo group or the like, a nitro group, an amino group, an acetylamino group, or an alkylamino group having 1 to 4 carbon atoms. Rb ₁₁ and _{Rb 12} are each independently a hydrogen atom, a sulfo group, a carboxy group, an alkyl group having 1 to 4 carbon atoms, or is preferably an alkoxy group having 1 to 4 carbon atoms, the _{Rb 11} and _{Rb 12} It is more preferable that at least one is a sulfo group, and it is further preferable that the _{number of substituents of Rb 11} and Rb ₁₂ is 2 (that is _{, both Rb 11} and Rb ₁₂ are not hydrogen atoms). As the alkoxy group having 1 to 4 carbon atoms having a sulfo group, a linear alkoxy group having 1 to 4 carbon atoms having a sulfo group is preferable. In the alkoxy group having 1 to 4 carbon atoms having a sulfo group, the substituent of the sulfo group is preferably an alkoxy group terminal. The alkoxy group having a sulfo group and having 1 to 4 carbon atoms is more preferably a 3-sulfopropoxy group or a 4-sulfobutoxy group.

Examples of the aromatic amines represented by the general formula (7) include 4-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid, 2-aminobenzenesulfonic acid, 4-aminobenzoic acid, and 2-amino-5. -Methylbenzene sulfonic acid, 2-amino-5-methoxybenzene sulfonic acid, 4-amino-2-methylbenzene sulfonic acid, 3-amino-4-methoxybenzene sulfonic acid, 2-amino-4-sulfobenzoic acid, 2 -Amino-5-sulfobenzoic acid, etc., 5-aminoisophthalic acid, 2-amino-5-nitrobenzene sulfonic acid, 5-acetamide-2-aminobenzene sulfonic acid, 2-amino-5- (3-sulfopropoxy) benzene Examples thereof include sulfonic acid, 4-aminobenzene-1,3-disulfonic acid, 2-aminobenzene-1,4-disulfonic acid, and 4-aminobenzenesulfonic acid, 2-amino-5-methoxybenzenesulfonic acid, 4-Amino-2-methylbenzene sulfonic acid and 4-aminobenzene-1,3-disulfonic acid are particularly preferable. Further, the aromatic amines represented by the general formula (7) may have a naphthotriazole group as a substituent on the phenyl group. Examples of the naphthotriazole group include a 6,8-disulfonaphthotriazole group, a 7,9-disulfonaphtholazole group, a 7-sulfonaphthotriazole group, a 5-sulfonaphthtriazole group and the like. In this case, the naphthotriazole group is particularly preferably at the p-position of the phenyl group.

Naftylamine represented by the general formula (9), which is a starting material (raw material compound) for synthesizing the azo compound represented by the general formula (1) when _{Ab 1 is a naphthyl group having a substituent. Rb 13} of sulfonic acids has a hydrogen atom, a hydroxy group, a carboxy group, a sulfo group, a tosylated hydroxy group, an amino group, a substituted amino group, a nitro group, a substituted amide group, or a sulfo group and has 1 to 4 carbon atoms. The alkoxy group is preferably an alkoxy group having a hydrogen atom, a sulfo group, and a sulfo group and having 1 to 4 carbon atoms. Further, Rb ₁₃ is preferably a lower alkoxy group having a hydrogen atom, a hydroxy group, a carboxy group, or a sulfo group. The alkoxy group having a sulfo group and having 1 to 4 carbon atoms is preferably a linear alkoxy group having a sulfo group and having 1 to 4 carbon atoms. In the alkoxy group having a sulfo group and having 1 to 4 carbon atoms, the substituent of the sulfo group is preferably an alkoxy group terminal. The alkoxy group having a sulfo group and having 1 to 4 carbon atoms is preferably a 3-sulfopropoxy group or a 4-sulfobutoxy group. In the naphthylamine sulfonic acids represented by the general formula (9), the substitution position of the sulfo group may be on either benzene nucleus of the naphthalene ring. When the number q of the sulfo groups is 1, the substitution position of the sulfo groups is preferably any of the 1-position, 3-position, and 6-position, and the number q of the sulfo groups is 2 or 3. In some cases, the combination of sulfo group substitution positions is preferably a combination of two or three selected from the group consisting of the 1-position, 3-position, 6-position, and 7-position.

Examples of the naphthylamine sulfonic acid represented by the general formula (9) include 2-aminonaphthalene-1-sulfonic acid, 8-aminonaphthalene-1-sulfonic acid, 5-aminonaphthalene-1-sulfonic acid, and 5-aminonaphthalene-1-sulfonic acid. Aminonaphthalene-2-sulfonic acid, 8-aminonaphthalene-2-sulfonic acid, 3-aminonaphthalene-1-sulfonic acid, 6-aminonaphthalene-2-sulfonic acid, 4-aminonaphthalene-1-sulfonic acid, 7- Aminonaphthalene-1,3-disulfonic acid, 6-aminonaphthalene-1,3-disulfonic acid, 3-amino-7-nitronaphthalene-1,5-disulfonic acid, 4-aminonaphthalene-1,6-disulfonic acid, 4-Aminonaphthalene-1,5-disulfonic acid, 5-aminonaphthalene-1,3-disulfonic acid, 3-aminonaphthalene-1,5-disulfonic acid, 2-aminonaphthalene-1,5-disulfonic acid, 4- Aminonaphthalene-1,6-disulfonic acid, 7-aminonaphthalene-1,3,6-trisulfonic acid, 7-aminonaphthalene-1,3,5-trisulfonic acid, 8-aminonaphthalene-1,3,6 -Trisulfonic acid, 5-aminonaphthalene-1,3,6-trisulfonic acid, 7-amino-3- (3-sulfopropoxy) naphthalene-1-sulfonic acid, 7-amino-3- (4-sulfobutoxy) ) Naphthalene-1-sulfonic acid, 7-amino-4- (3-sulfopropoxy) naphthalene-2-sulfonic acid, 7-amino-4- (4-sulfobutoxy) naphthalene-2-sulfonic acid, 6-amino- 4- (3-sulfopropoxy) naphthalene-2-sulfonic acid, 6-amino-4- (4-sulfobutoxy) naphthalene-2-sulfonic acid, 2-amino-5- (3-sulfopropoxy) naphthalene-1, 7-Disulfonic acid, 6-amino-4- (3-sulfopropoxy) naphthalene-2,7-disulfonic acid, 7-amino-3- (3-sulfopropoxy) naphthalene-1,5-disulfonic acid and the like. However, preferably, 7-aminonaphthalene-1,3-disulfonic acid, 6-aminonaphthalene-1,3-disulfonic acid, 7-aminonaphthalene-1,3,6-trisulfonic acid, 7-amino-4. -(3-Sulfopropoxy) naphthalene-2-sulfonic acid, 6-amino-4- (3-sulfopropoxy) naphthalene-2-sulfonic acid, and particularly preferably 7-aminonaphthalene-1,3-disulfonic acid. , 7-Aminonaphthalene -1,3,6-trisulfonic acid and 7-amino-4- (3-sulfopropoxy) naphthalene-2-sulfonic acid.

_{Rb 1} and Rb ₂ contained in the aniline represented by the general formula (8) which is a primary coupling component, and Rb contained in the aniline represented by the general formula (10) which is a secondary coupling component. ₃ and Rb ₄ independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms and having a sulfo group, but preferably. It is a hydrogen atom, a methyl group, a methoxy group, or a 3-sulfopropoxy group or a 4-sulfobutoxy group, and more preferably a hydrogen atom, a methyl group, or a methoxy group. The combination of the substitution positions of Rb ₁ and Rb ₂ and the combination of the substitution positions of Rb ₃ and Rb ₄ are independently the combination of the 2-position and the 6-position, and the 2-position and 5 with respect to the amino group. The combination with the − position, or the combination of the 3-position and the 5-position is preferable, and the combination of the 2-position and the 5-position is more preferable. Examples of the anilins represented by the general formula (8) and the anilins having an alkoxy group having 1 to 4 carbon atoms having a sulfo group that can be used as the aniline represented by the general formula (10) are 3-. (2-Amino-4-methylphenoxy) Propane-1-sulfonic acid, 3- (2-aminophenoxy) Propane-1-sulfonic acid, 3- (2-Amino-4-methylphenoxy) butane-1-sulfonic acid And so on. Examples of other anilines that can be used as the anilines represented by the general formula (8) and the anilines represented by the general formula (10) include 2,5-dimethylaniline and 2,5-. Examples thereof include diethylaniline, 2-methoxy-5-methylaniline, 2,5-dimethoxyaniline, 3,5-dimethylaniline, 2,6-dimethylaniline and 3,5-dimethoxyaniline. These anilines may have an amino group protected by a protecting group. Examples of the protecting group include the ω-methanesulfo group. The anilines represented by the general formula (8) used for the primary coupling and the anilines represented by the general formula (10) used for the secondary coupling are the same but different. You may.

The aniline having a methoxy group represented by the general formula (12), which is a tertiary coupling component, may be an aniline having a methoxy group at the o-position with respect to the amino group, but preferably 2, They are 5-dimethoxyaniline, 2-methoxyaniline, and 2-methoxy-5-methylaniline.

_{The substituent Xb 1} contained in the naphthols represented by the general formula (14), which is a quaternary coupling component, may have a substituent (excluding a phenyl group and a benzoyl group), and is an amino group or a substituent. A phenylamino group which may have a substituent, a benzoylamino group which may have a substituent, a phenylazo group which may have a substituent, or a naphthotriazole group which may have a substituent. Although represented, it may preferably have one or two substituents selected from the group consisting of a methyl group, a methoxy group, a sulfo group, an amino group, and an alkylamino group having 1 to 4 carbon atoms. A benzoylamino group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, which may have one substituent selected from the group consisting of a phenylamino group, a hydroxy group, an amino group, and a carboxyethylamino group. A phenylazo group which may have 1 to 3 substituents selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms, an amino group, and a carboxyethylamino group, or one or two sulfo groups. A naphthotriazole group substituted with, more preferably one or two substitutions selected from the group consisting of a methyl group, a methoxy group, a sulfo group, an amino group, and an alkylamino group having 1 to 4 carbon atoms. A phenylamino group which may have a group, or a benzoylamino group which may have one substituent selected from the group consisting of a hydroxy group, an amino group, and a carboxyethylamino group, and further. Preferably, it may have one or two substituents selected from the group consisting of a methyl group, a methoxy group, a sulfo group, an amino group, and an alkylamino group having 1 to 4 carbon atoms. Is. When Xb ₁ is a phenylamino group having one substituent, a benzoylamino group having one substituent, or a phenylazo group having one substituent, the substitution position of the substituent is not particularly limited, but is not limited. When Xb ₁ is a phenylamino group having one substituent, a benzoylamino group having one substituent, or a phenylazo group having one substituent, the p-position is particularly preferable.

The azo compound of the present invention may exist in the form of a free acid represented by the general formula (1) or in the form of a salt thereof. Examples of the salt include alkali metal salts, alkaline earth metal salts, alkylamine salts, alkanolamine salts, ammonium salts and the like. When used for dyeing a substrate for a polarizing element, the salt is preferably a sodium salt, a potassium salt, or an ammonium salt. The azo compound represented by the general formula (1) can be isolated in the form of a free acid by adding a mineral acid after the coupling reaction, and the isolated azo represented by the general formula (1) can be isolated. By washing the compound with water or acidified water, the inorganic salt can be removed from the isolated azo compound represented by the general formula (1). In this way, an acid type azo compound represented by the general formula (1) having a low salt content can be obtained. Next, the azo compound represented by the general formula (1) of this acid type can be neutralized with a desired inorganic or organic base in an aqueous medium to obtain a solution of the corresponding salt. Alternatively, at the time of salting after the coupling reaction, the azo compound represented by the general formula (1) can be converted into a sodium salt by using, for example, sodium chloride, and for example, potassium chloride can be used in the general formula (1). The represented azo compound can also be a potassium salt. In this way, the azo compound represented by the general formula (1) can be used as a desired salt.

Specific examples of the azo compound represented by the general formula (1) or (2) of the present invention or a salt thereof are given below. Examples of compounds are represented in the form of free acids.

[Polarizing element]
The polarizing element of the present invention contains a base material and the above-mentioned azo compound of the present invention. The azo compound of the present invention is preferably adsorbed on the substrate. The azo compound used as a dye in the polarizing element of the present invention is generally a known diazotized or cup according to a means for synthesizing an azo dye known in the art (for example, page 626 of Non-Patent Document 1). It can be manufactured by ringing. A polarizing element can be produced by dissolving an azo compound in a solution and impregnating a substrate in a dyeing step.

で表されるアゾ化合物又はその塩をさらに含むことが好ましい。これにより、さらに高い偏光性能を有する偏光素子を実現できる。前記一般式（３）で表されるアゾ化合物又はその塩も、前記基材に吸着していることが好ましい。The polarizing element of the present invention is a dichroic dye in addition to the above-mentioned azo compound of the present invention, and has the following general formula (3).

It is preferable that the azo compound represented by (1) or a salt thereof is further contained. This makes it possible to realize a polarizing element having even higher polarization performance. The azo compound represented by the general formula (3) or a salt thereof is also preferably adsorbed on the substrate.

In the general formula (3), Ar ₁ represents a phenyl group having a substituent or a naphthyl group having a substituent, and Rr _{1 to Rr 6} independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and carbon. Represents an alkoxy group of number 1 to 4 or an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and Xr ₁ is an amino group or a substituent which may have a substituent (excluding a phenyl group and a benzoyl group). A phenylamino group which may have a substituent, a benzoylamino group which may have a substituent, a phenylazo group which may have a substituent, or a naphthotriazole group which may have a substituent. Represented, m and n independently represent 0 or 1, respectively.

（式中、Ａｂ_１、Ｒｂ_１〜Ｒｂ_５、及びＸｂ_１は、一般式（１）中と同じ意味を表す。）
で表されるアゾ化合物であることが好ましい。The azo compound represented by the general formula (3) has the following general formula (5).

(In the formula, Ab ₁ , Rb _{1 to Rb 5} , and Xb ₁ have the same meanings as in the general formula (1).)
It is preferably an azo compound represented by.

In the general formula (3) or (5), Ar ₁ represents a phenyl group having a substituent or a naphthyl group having a substituent, and Rr _{1 to Rr 6} are independently hydrogen atoms and 1 to 4 carbon atoms, respectively. Represents an alkyl group, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and Xr ₁ may have a substituent (excluding a phenyl group and a benzoyl group). It has a good amino group, a phenylamino group which may have a substituent, a benzoylamino group which may have a substituent, a phenylazo group which may have a substituent, or a substituent. May represent a naphthotriazole group, where m and n independently represent 0 or 1, respectively.

_{Rr 1 to Rr 6} in the general formula (3) or (5) are each independently preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and particularly preferably a hydrogen atom or a methyl group. .. _{One of Rr 5} and Rr ₆ in the general formula (3) or (5) is an alkoxy group having 1 to 4 carbon atoms, and the other is an alkyl group having 1 to 4 carbon atoms or an alkoxy having 1 to 4 carbon atoms. It is preferably a group.

_{Xr 1} in the general formula (3) or (5) is preferably one selected from the group consisting of a methyl group, a methoxy group, a sulfo group, an amino group, and an alkylamino group having 1 to 4 carbon atoms. Alternatively, a benzoylamino group may have one substituent selected from the group consisting of a phenylamino group, a hydroxy group, an amino group, and a carboxyethylamino group which may have two substituents. , A hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an amino group, and a carboxyethyl amino group having 1 to 3 substituents selected from the group. A good phenylazo group, or a naphthotriazole group substituted with one or two sulfo groups, more preferably from a methyl group, a methoxy group, a sulfo group, an amino group, and an alkylamino group having 1 to 4 carbon atoms. It has one substituent selected from the group consisting of a phenylamino group, a hydroxy group, an amino group, and a carboxyethylamino group, which may have one or two substituents selected from the group. It is a benzoylamino group which may be used, or a naphthotriazole group substituted with one or two sulfo groups, and is particularly preferably selected from the group consisting of a methyl group, a methoxy group, a sulfo group and an amino group. It may have one or two substituents, or may have one substituent selected from the group consisting of hydroxy, amino, and carboxyethylamino groups. It is a benzoylamino group.

_{Ar 1} in the general formula (3) or (5) is a phenyl group having a substituent or a naphthyl group having a substituent, but a sulfo group, a carboxy group, an alkyl group having 1 to 4 carbon atoms, and an alkyl group having 1 to 4 carbon atoms. It consists of a phenyl group having one or two substituents selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having a sulfo group, a hydroxy group, and a sulfo group and having 1 to 4 carbon atoms. It is preferably a naphthyl group having 2 or 3 substituents selected from the group.

_{In Ar 1} in the general formula (3) or (5), the substituent on the phenyl group is a sulfo group, a carboxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a hydroxy group. , An alkoxy group having 1 to 4 carbon atoms having a sulfo group, a sulfo-substituted naphthotriazole group, a nitro group, an amino group, an acetylamino group, or an alkylamino group having 1 to 4 carbon atoms is preferable. _{In Ar 1} in the general formula (3) or (5), the substituent on the naphthyl group is preferably a sulfo group, a hydroxy group, or an alkoxy group having 1 to 4 carbon atoms having a sulfo group. _{Ar 1} in the general formula (3) or (5) is preferably a phenyl group or a naphthyl group having one or more sulfo groups or carboxy groups, and in order to improve durability, a sulfo group or a carboxy group. It is more preferable that it is a phenyl group or a naphthyl group having two or more of. _{Ar 1} in the general formula (3) or (5) is more preferably a phenyl group having a sulfo group or a carboxy group in order to further improve the polarization characteristics and produce a neutral-colored polarizing element. ..

Although m and n in the general formula (3) may be independently 0 or 1, respectively, at least one of m and n is preferably 1 in order to obtain good polarization performance in the polarizing element of the present invention. , M and n are both 1 more preferably. The substituted amino group is not particularly limited, and includes, for example, an alkyl group having 1 to 4 carbon atoms or an amino group substituted with an acyl group. Further, the substituted amide group is not particularly limited, and includes an alkyl group having 1 to 4 carbon atoms, a phenyl group which may have a substituent, or an amide group in which a naphthyl group which may have a substituent is substituted. Is done.

Examples of the method for synthesizing the azo compound represented by the general formula (3) or a salt thereof include JP-A-9-302250, Japanese Patent No. 4662853, International Publication No. 2012/108169, and International Publication No. 2012 /. It can be produced by the method described in No. 108173 and the like, but is not limited thereto.

Examples of the azo compound represented by the general formula (3) or a salt thereof include C.I. I. Direct Red 81, C.I. I. Direct Red 117, C.I. I. Direct Red 127, an azo compound described in WO 2005/075772 (eg, an azo compound described in Example 1 of WO 2005/075772), described in Japanese Patent No. 4662853. Dyes, dyes described in International Publication No. 2013/008735, azo compounds described in JP-A-2-61988, azo compounds described in JP2013-57909, International Publication No. Azo compounds described in 2012/108169 (for example, azo compounds represented by the formulas (8), (9), (10), (17), (21) of International Publication No. 2012/108169) and the like. Is exemplified, but the present invention is not limited to these.

The azo compound represented by the general formula (3) or a salt thereof may be contained in the polarizing element in the form of a free acid represented by the general formula (3), and is represented by the general formula (3). It may be contained in the polarizing element in the form of a salt of the azo compound. The salt may be an alkali metal salt such as a lithium salt, a sodium salt, and a potassium salt, or may be an organic salt such as an ammonium salt or an alkylamine salt. The salt is preferably a lithium salt or a sodium salt, and more preferably a sodium salt.

Next, specific examples of the azo compound represented by the general formula (3) or a salt thereof that can be used in the polarizing element of the present invention will be given below. In the following compound examples, substituents such as a sulfo group, a carboxy group and a hydroxy group are represented in the form of a free acid, but such a substituent may be in the form of a salt.

In the polarizing element of the present invention, the content of the azo compound represented by the general formula (3) or a salt thereof is 100 parts by weight by weight of the content of the azo compound represented by the general formula (1) or a salt thereof. On the other hand, it is preferably in the range of 1 to 200 parts by weight, and more preferably in the range of 50 to 100 parts by weight.

で表されるアゾ化合物又はその塩をさらに含むことが好ましく、前記一般式（３）で表されるアゾ化合物又はその塩と、前記一般式（４）で表されるアゾ化合物又はその塩との両方をさらに含むことがより好ましい。これにより、さらに高い偏光度を有する偏光素子を実現できる。前記一般式（４）で表されるアゾ化合物又はその塩も、前記基材に吸着していることが好ましい。In addition to the above-mentioned azo compound represented by the general formula (1) of the present invention or a salt thereof, the polarizing element of the present invention has the following general formula (4).

It is preferable that the azo compound represented by the above formula (3) or a salt thereof is further contained, and the azo compound represented by the general formula (3) or a salt thereof and the azo compound represented by the general formula (4) or a salt thereof. It is more preferable to further include both. Thereby, a polarizing element having a higher degree of polarization can be realized. The azo compound represented by the general formula (4) or a salt thereof is also preferably adsorbed on the substrate.

In the general formula (4), Ay ₁ represents a sulfo group, a carboxy group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and Ry _{1 to Ry 4} are each. Independently, it represents a hydrogen atom, a sulfo group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and p represents an integer of 1 to 3 carbon atoms. _{Ay 1} in the general formula (4) is preferably a carboxy group or a sulfo group.

As a method for synthesizing the azo compound represented by the general formula (4) or a salt thereof, for example, the synthesis method described in Non-Patent Document 1 or the synthesis method described in International Publication No. 2007/138980 is adopted. However, it is not limited to these.

Examples of the azo compound represented by the general formula (4) or a salt thereof include C.I. I. Direct Yellow 12, C.I. I. Direct Yellow 72, C.I. I. Direct Orange 39 (CAS No .: 1325-54-8), an azo compound described in WO 2007/138980 (eg, a compound example described in Example 1 of WO 2007/138980). 111 azo compounds) can be used, but is not limited thereto.

The azo compound represented by the general formula (4) or a salt thereof may be contained in the polarizing element in the form of a free acid represented by the general formula (4), and is represented by the general formula (4). It may be contained in the polarizing element in the form of a salt of the azo compound. The salt may be an alkali metal salt such as a lithium salt, a sodium salt, and a potassium salt, or may be an organic salt such as an ammonium salt or an alkylamine salt. The salt is preferably a lithium salt or a sodium salt, and more preferably a sodium salt.

Next, specific examples of the azo compound represented by the general formula (4) or a salt thereof that can be used in the polarizing element of the present invention will be given below. In the following compound examples, the sulfo group and the carboxy group are represented in the form of a free acid, but the sulfo group and the carboxy group may be in the form of a salt.

In the polarizing element of the present invention, the content of the azo compound represented by the general formula (4) or a salt thereof is 100 parts by weight by weight of the content of the azo compound represented by the general formula (1) or a salt thereof. On the other hand, it is preferably in the range of 1 to 200 parts by weight, and more preferably in the range of 50 to 100 parts by weight.

In the polarizing element of the present invention, other organic dyes other than the azo compounds represented by the general formulas (1), (3), and (4) or salts thereof, for example, Non-Patent Document 2, depending on the color adjustment and the like. One or more of the azo compounds described in the above may be used in combination with the azo compound represented by the general formula (1) of the present invention or a salt thereof. The other organic dye to be used in combination is not particularly limited, but is for dyeing a hydrophilic polymer, and has a wavelength region different from the absorption wavelength region of the azo compound represented by the general formula (1) of the present invention or a salt thereof. A dye having an absorption property and having a high dichroism is preferable. Examples of other organic dyes include the azo compound described in Non-Patent Document 2 (for example, CI Direct Yellow 28) and C.I. I. Direct Red 2, C.I. I. Direct Red 31, C.I. I. Direct Red 79, C.I. I. Direct Red 247, C.I. I. Direct Green 80, C.I. I. Direct Green 59, C.I. I. Direct Blue 202, C.I. I. Direct violet 9 and the like can be mentioned. These azo compounds are used in the form of free acids or salts such as alkali metal salts (eg, sodium salts, potassium salts, lithium salts), ammonium salts, and amine salts. When other organic dyes are used in combination, if necessary, the target polarizing element is a more neutral color polarizing element, a polarizing element having a characteristic color, a color polarizing element for a liquid crystal projector, and other color polarizing elements. The types of other organic dyes to be blended differ depending on which one is used. The compounding amount of other organic dyes (in the case of two or more kinds, the total compounding amount of them) is not particularly limited, but generally, the azo represented by the general formula (1) of the present invention is used. 0 with respect to 100 parts by weight of the total amount of the compound or the salt thereof, the azo compound represented by the general formula (3) or the salt thereof, and the azo compound represented by the general formula (4) or the salt thereof. It is preferably in the range of 1 to 10 parts by weight.

As the base material, a hydrophilic polymer is preferable. The hydrophilic polymer is not particularly limited, and examples thereof include polyvinyl alcohol or a derivative thereof, an amylose-based resin, a starch-based resin, a cellulosic resin, a polyacrylate-based resin, and the like. As the base material containing the azo compound of the present invention, polyvinyl alcohol or a derivative thereof (hereinafter referred to as "polyvinyl alcohol-based resin") is most preferable from the viewpoint of dyeability and crosslinkability. The polarizing element of the present invention can be produced by adsorbing the azo compound and other compounds of the present invention on the film-shaped base material and applying an orientation treatment such as stretching.

The method for producing the polyvinyl alcohol-based resin is not particularly limited, and a known production method can be adopted. As a method for producing a polyvinyl alcohol-based resin, for example, it can be obtained by saponifying a polyvinyl acetate-based resin (a homopolymer or a copolymer of vinyl acetate). Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids and the like. The polyvinyl alcohol or a derivative thereof may be further modified, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes.

The saponification degree of the polyvinyl alcohol-based resin is usually preferably 85% or more, more preferably 95 mol% or more, further preferably 99 mol% or more, and particularly preferably 99.5 mol% or more. If the saponification degree is less than the above lower limit, the polyvinyl alcohol-based resin is likely to be eluted, which induces in-plane unevenness in optical characteristics, deterioration of dyeability in the dyeing process, and cutting in the stretching process, resulting in remarkable productivity. It may be lowered, which is not preferable.

In order to improve the optical properties of the polarizing element of the present invention, the degree of polymerization of the polyvinyl alcohol-based resin is preferably 1000 to 10000, more preferably 2000 to 10000, and preferably 3500 to 10000. It is more preferably 5000 to 10000, and particularly preferably 5000 to 10000. When the degree of polymerization exceeds 10,000, the polyvinyl alcohol-based resin becomes hard, the film forming property and stretchability decrease, and the productivity decreases. Therefore, the degree of polymerization is preferably 10,000 or less from an industrial point of view. The degree of polymerization of the polyvinyl alcohol-based resin means the degree of viscosity average polymerization, and can be obtained by a method well known in the art.

Hereinafter, a specific method for manufacturing a polarizing element will be described by taking the case where the base material is a film made of a polyvinyl alcohol-based resin as an example.

First, a film raw fabric made of a polyvinyl alcohol-based resin is obtained by forming a film of a polyvinyl alcohol-based resin. As a method for forming a polyvinyl alcohol-based resin, in addition to a method of melt-extruding a hydrous polyvinyl alcohol-based resin, a casting film forming method, a wet film forming method (a method of forming a film by discharging into a poor solvent), and gel formation. A film method (a method in which an aqueous solution of a polyvinyl alcohol-based resin is once cooled and gelled, and then the solvent is extracted and removed), a cast film-forming method (a method in which an aqueous solution of a polyvinyl alcohol-based resin is poured onto a substrate and dried), and these methods. A combination method can be adopted, but the method is not limited to these methods.

When a solvent is used for film formation, the solvent is not particularly limited, and for example, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene glycol, glycerin, propylene glycol, diethylene glycol, etc. Examples thereof include triethylene glycol, tetraethylene glycol, trimethylolpropane, ethylenediamine, diethylenetriamine, and water. The solvent may be used alone or in combination of two or more. The amount of the solvent used in the film formation is preferably 70 to 95% by weight based on the entire film formation stock solution (mixed solution containing the polyvinyl alcohol-based resin and the solvent used in the film formation), but is not limited. However, if the amount of the solvent is less than 70% by weight, the viscosity of the film-forming stock solution becomes high, filtration and defoaming during preparation become difficult, and it becomes difficult to obtain a film raw fabric without foreign matter or defects. Further, if the amount of the solvent exceeds 95% by weight, the viscosity of the film-forming stock solution becomes too low, it is difficult to control the target thickness, the influence of the surface fluctuation due to the wind during drying becomes large, and the drying time becomes long. The productivity is reduced.

A plasticizer may be used in producing the raw film. Examples of the plasticizer include, but are not limited to, glycerin, diglycerin, ethylene glycol, propylene glycol, low molecular weight polyethylene glycol and the like. The amount of the plasticizer used is also not particularly limited, but is usually preferably in the range of 5 to 15 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin.

Examples of the method for drying the raw film after film formation include, but are not limited to, drying with hot air, contact drying with a hot roll, and drying with an infrared heater. One of these drying methods may be used alone, or two or more of them may be used in combination. The drying temperature is also not particularly limited, but is preferably in the range of 50 to 70 ° C.

The dried film raw fabric is preferably heat-treated in order to control its swelling degree within a predetermined range described later. Examples of the heat treatment method for the film raw material after the film formation include a method using hot air and a method in which the film raw material is brought into contact with a hot roll, and the method is not particularly limited as long as it can be treated by heat. One of these methods may be used alone, or two or more may be used in combination. The heat treatment temperature is not particularly limited, but is preferably in the range of 110 to 140 ° C. The heat treatment time is preferably 1 to 10 minutes, but is not particularly limited.

The thickness of the film raw material thus obtained is preferably 20 to 100 μm, more preferably 20 to 80 μm, and even more preferably 20 to 60 μm. If the thickness is less than 20 μm, the film is likely to break. If the thickness exceeds 100 μm, the stress applied to the film during stretching increases, the mechanical load in the stretching process increases, and a large-scale device capable of withstanding the load is required.

Next, a swelling step is performed on the raw film made of the polyvinyl alcohol-based resin obtained as described above.

The swelling step is performed by immersing a raw film made of a polyvinyl alcohol-based resin in a solution at 20 to 50 ° C. for 30 seconds to 10 minutes. The solution is preferably an aqueous solution. Since the swelling of the film also occurs during the dyeing treatment of the azo compound, the swelling step can be omitted when the time for manufacturing the polarizing element is to be shortened.

The swelling degree F of the original film is preferably 180 to 260%, more preferably 200 to 240%, and even more preferably 210 to 230%. When the swelling degree F is less than 200%, the elongation at the time of stretching is small, and the possibility of breaking at a low magnification is high. If it is less than 180%, the elongation at the time of stretching is remarkably lowered, the possibility of breaking is high, and it becomes difficult to perform sufficient stretching. Further, when the swelling degree F exceeds 240%, the swelling becomes excessive, wrinkles and slacks occur, and it is becoming a cause of cutting during stretching. If the swelling degree F exceeds 260%, it may cause remarkably wrinkles and sagging, which is not preferable. In order to control the swelling degree F, for example, it is possible to obtain a suitable swelling degree F at a temperature and time when heat-treating the film raw fabric after film formation.

The swelling degree F of the film raw fabric can be measured by a method well known in the art, and is measured by, for example, the following method. First, the raw film is cut into 5 cm × 5 cm and immersed in 1 liter of distilled water at 30 ° C. for 4 hours. The soaked film is taken out from the distilled water, sandwiched between two sheets of filter paper, and the water droplets on the surface of the film are absorbed by the filter paper, and then the weight [β (g)] of the film soaked in water is measured. Further, the film that has been immersed and has absorbed water droplets is dried in a dryer at 105 ° C. for 20 hours, cooled in a desiccator for 30 minutes, and then the weight [γ (g)] of the dried film is measured. Then, the swelling degree F of the film raw fabric is calculated by the following mathematical formula (v).
Swelling degree F = 100 × β / γ (%) ・ ・ ・ (v)

After the swelling step, a dyeing step is performed. In the dyeing step, the azo compound of the present invention (azo compound represented by the general formula (1) or a salt thereof) is, if necessary, another azo compound (azo compound represented by the general formula (3) or a salt thereof). , An azo compound represented by the general formula (4) or a salt thereof, etc.) can be adsorbed on a polyvinyl alcohol-based resin film.

The dyeing step is not particularly limited as long as it is a method of adsorbing the azo compound on the polyvinyl alcohol-based resin film, but is performed, for example, by immersing the polyvinyl alcohol-based resin film in a solution containing the azo compound. The solution temperature in this dyeing step is preferably 5 to 60 ° C., more preferably 20 to 50 ° C., and particularly preferably 35 to 50 ° C. The time of immersion in the solution can be appropriately adjusted, but is preferably adjusted to 30 seconds to 20 minutes, more preferably 1 to 10 minutes. As a dyeing method, a method of immersing the polyvinyl alcohol-based resin film in the solution is preferable, but a method of applying the solution to the polyvinyl alcohol-based resin film may also be used.

The solution containing the azo compound, which is a bicolor dye, can contain sodium carbonate, sodium hydrogencarbonate, sodium chloride, sodium sulfate, anhydrous sodium sulfate, sodium tripolyphosphate and the like as a dyeing aid. The content of these dyeing aids can be adjusted to an arbitrary concentration depending on the time and temperature of dyeing due to the dyeability of the azo compound, but is preferably 0 to 5% by weight, more preferably 0.1 to 2% by weight.

After the dyeing step and before entering the next step, a washing step (hereinafter, referred to as "cleaning step 1") can be performed. The cleaning step 1 is a step of cleaning the dye solvent adhering to the surface of the polyvinyl alcohol-based resin film with a cleaning liquid in the dyeing step. By performing the washing step 1, it is possible to suppress the transfer of the dye into the liquid to be treated next. In the cleaning step 1, water is generally used as the cleaning liquid. As a cleaning method, a method of immersing in a cleaning liquid is preferable, but a method of applying the cleaning liquid to a polyvinyl alcohol-based resin film can also be used. The washing time is not particularly limited, but is preferably 1 to 300 seconds, more preferably 1 to 60 seconds. The temperature of the cleaning liquid in the cleaning step 1 needs to be a temperature at which the hydrophilic polymer does not dissolve, and is generally 5 to 40 ° C.

After the dyeing step or after the washing step 1, a step of incorporating a cross-linking agent and / or a water resistant agent into the polyvinyl alcohol-based resin film can be performed. Examples of the cross-linking agent include a boron compound such as boric acid, borax or ammonium borate, a polyvalent aldehyde such as glyoxal or glutaaldehyde, a polyvalent isocyanate compound such as biuret type, isocyanurate type or block type, and titanium. Titanium-based compounds such as oxysulfate can be used, and ethylene glycol glycidyl ether, polyamide epichlorohydrin and the like can also be used, but boric acid is preferable. Examples of the water resistant agent include succinic acid peroxide, ammonium persulfate, calcium perchlorate, benzoin ethyl ether, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, ammonium chloride and magnesium chloride.

A step of incorporating the cross-linking agent and / or the water-resistant agent into the polyvinyl alcohol-based resin film is performed using at least one of the cross-linking agents and / or the water-resistant agents shown above. The cross-linking agent and / or water resistant agent is usually used in the form of a solution dissolved in a solvent. The solvent is preferably, but not limited to, water. The concentration of the cross-linking agent and / or the water-resistant agent in the solvent in the step of containing the cross-linking agent and / or the water-resistant agent is 0.1 to 6. 0% by weight is preferable, and 1.0 to 4.0% by weight is more preferable. The temperature of the solvent in this step is preferably 5 to 70 ° C, more preferably 5 to 50 ° C. As a method of incorporating a cross-linking agent and / or a water-resistant agent into the polyvinyl alcohol-based resin film, a method of immersing the polyvinyl alcohol-based resin film in a solution of the cross-linking agent and / or the water-resistant agent is preferable. A method of applying or coating on a resin film may also be used. The treatment time in this step is preferably 30 seconds to 6 minutes, more preferably 1 to 5 minutes. However, it is not essential to include a cross-linking agent and / or a water-resistant agent in the polyvinyl alcohol-based resin film, and when it is desired to shorten the manufacturing time of the polarizing element or when the cross-linking treatment or the water-resistant treatment is unnecessary, This processing step may be omitted.

A stretching step is performed after the dyeing step, after the washing step 1, or after the step of adding a cross-linking agent and / or a water resistant agent. The stretching step is a step of stretching the polyvinyl alcohol-based resin film uniaxially. The stretching method may be either a wet stretching method or a dry stretching method. The present invention can be achieved if the draw ratio is 3 times or more, but it is preferably 5 to 7 times.

In the case of the dry stretching method, when the stretching heating medium is an air medium, the temperature of the air medium during stretching is preferably room temperature to 180 ° C. Further, it is preferable to carry out the stretching treatment in an atmosphere having a humidity of 20 to 95% RH. Examples of the stretching method include an inter-roll zone stretching method, a roll heating stretching method, a pressure stretching method, an infrared heating stretching method, and the like, but the stretching method is not limited. The stretching step can be carried out by one-step stretching, but can also be carried out by two-stage or more multi-step stretching.

In the case of the wet stretching method, the polyvinyl alcohol-based resin film is stretched in water, a water-soluble organic solvent, or a mixed solution thereof. It is preferable to carry out the stretching treatment while immersing the polyvinyl alcohol-based resin film in the solution containing the cross-linking agent and / or the water-resistant agent. Examples of the cross-linking agent include a boron compound such as boric acid, borax or ammonium borate, a polyvalent aldehyde such as glyoxal or glutaaldehyde, a polyvalent isocyanate compound such as biuret type, isocyanurate type or block type, and titanium. Titanium-based compounds such as oxysulfate can be used, but ethylene glycol glycidyl ether, polyamide epichlorohydrin and the like can also be used. Examples of the water resistant agent include succinic acid peroxide, ammonium persulfate, calcium perchlorate, benzoin ethyl ether, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, ammonium chloride and magnesium chloride.

A step of incorporating the cross-linking agent and / or the water-resistant agent into the polyvinyl alcohol-based resin film is performed using at least one of the cross-linking agents and / or the water-resistant agents shown above. The cross-linking agent and / or water resistant agent is usually used in the form of a solution dissolved in a solvent. The solvent is preferably, but not limited to, water. Contains the cross-linking agent and / or water resistant agent

The polyvinyl alcohol-based resin film is stretched in a solution containing at least one of the above-mentioned cross-linking agents and / or water-resistant agents. Boric acid is preferable as the cross-linking agent. The concentration of the cross-linking agent and / or the water resistant agent in the stretching step is preferably, for example, 0.5 to 15% by weight, more preferably 2.0 to 8.0% by weight. The draw ratio is preferably 2 to 8 times, more preferably 5 to 7 times. The stretching temperature is preferably 40 to 60 ° C, more preferably 45 to 58 ° C. The stretching time is usually 30 seconds to 20 minutes, but more preferably 2 to 5 minutes. The wet stretching step can be performed by one-step stretching, but can also be performed by two-stage or more multi-step stretching.

After the stretching step, a cross-linking agent and / or a water resistant agent may precipitate on the film surface, or foreign matter may adhere to the film surface. Therefore, a cleaning step of cleaning the film surface (hereinafter referred to as “cleaning step 2”) is performed. It can be carried out. The washing time is preferably 1 second to 5 minutes. As a cleaning method, a method of immersing in a cleaning liquid is preferable, but a method of applying or coating the cleaning liquid on a polyvinyl alcohol-based resin film can also be used. The cleaning treatment may be a one-step treatment or a multi-step treatment of two or more steps. The temperature of the cleaning liquid in the cleaning step is not particularly limited, but is usually 5 to 50 ° C, preferably 10 to 40 ° C.

Examples of the solvent used in the treatment steps up to this point include water; dimethylsulfoxide; N-methylpyrrolidone; methanol, ethanol, propanol, isopropyl alcohol, glycerin, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and tri. Alcohols such as methylolpropane; solvents such as amines such as ethylenediamine or diethylenetriamine are examples, but are not limited thereto. It is also possible to use a mixture of one or more of these solvents. The most preferred solvent is water.

After the stretching step or the washing step 2, a step of drying the polyvinyl alcohol-based resin film is performed. The drying treatment can be carried out by natural drying, but in order to further improve the drying efficiency, the surface moisture can be removed by compression with a roll, an air knife, a water absorbing roll or the like, and together with such moisture removal. Alternatively, air drying can be performed instead of such moisture removal. The temperature of the drying treatment is preferably 20 to 100 ° C, more preferably 60 to 100 ° C. The drying treatment time can be in the range of 30 seconds to 20 minutes, but is preferably 5 to 10 minutes.

In the present invention, in order to further improve the polarization performance, iodine is contained in the polarizing element by adsorbing iodine on the substrate using, for example, a dyeing solution containing iodine within a range in which the desired durability can be maintained. Is also good. The stain contains iodine and iodide. As the iodide, for example, potassium iodide, ammonium iodide, cobalt iodide, zinc iodide and the like can be used, but the iodide is not limited to the iodide shown here. The iodine concentration is preferably 0.0001 to 0.5% by weight, more preferably 0.001 to 0.4% by weight. The iodide concentration is preferably 0.0001 to 8% by weight. As the treatment step in this case, for example, any one of the dyeing step, the washing step 1, the stretching step, and the washing step 2 or a plurality of steps thereof can be used. The treatment temperature is preferably 5 to 60 ° C, more preferably 5 to 50 ° C, and particularly preferably 10 to 40 ° C. The treatment time can be adjusted appropriately, but is preferably adjusted for 30 seconds to 20 minutes, more preferably 1 to 5 minutes.

As described above, the polarizing element of the present invention is excellent because the polarizing element containing the base material and the azo compound uses the azo compound represented by the general formula (1) as the azo compound. It has polarization performance.

〔Polarizer〕
The polarizing plate of the present invention includes the polarizing element of the present invention and a transparent protective layer provided on at least one surface of the polarizing element.
The transparent protective layer can be provided as a coating layer made of a transparent polymer or as a laminating layer of a transparent film. As the transparent polymer or transparent film forming the transparent protective layer, a transparent polymer or transparent film having high mechanical strength and good thermal stability is preferable. Examples of the transparent polymer or transparent film used for the transparent protective layer include cellulose acetate resins such as triacetyl cellulose and diacetyl cellulose or films thereof, acrylic resins or films thereof, polyvinyl chloride resins or films thereof, nylon resins or films thereof, and the like. Polyester resin or its film, polyarylate resin or its film, cyclic polyolefin resin or its film using cyclic olefin such as norbornene as a monomer, polyethylene, polypropylene, polyolefin having a cyclo system or norbornene skeleton or copolymer thereof, main chain Alternatively, a polymer (or resin) having an imide and / or amide side chain or a film thereof may be used. Further, as the transparent protective layer, a resin having a liquid crystal property or a film thereof may be provided. The thickness of the protective film is, for example, about 0.5 to 200 μm. One layer of resin or film may be provided on one side of the polarizing element, two or more layers of the same or different resin or film may be provided on one side of the polarizing element, and the same or different resin or film may be provided on both sides of the polarizing element. One or more layers may be provided.

An adhesive can be used to bond the transparent protective layer to the polarizing element. The adhesive is not particularly limited, but a polyvinyl alcohol adhesive is preferable. Examples of the polyvinyl alcohol adhesive include, but are limited to, Gosenol (registered trademark) NH-26 (manufactured by Nippon Synthetic Chem Industry Co., Ltd.) and Excelval (registered trademark) RS-2117 (manufactured by Kuraray Co., Ltd.). It is not something that is done. A cross-linking agent and / or a water resistant agent can be added to the adhesive. A maleic anhydride-isobutylene copolymer can be mixed with the polyvinyl alcohol adhesive, and in that case, a cross-linking agent can be further mixed if necessary. Examples of the maleic anhydride-isobutylene copolymer include Isoban (registered trademark) # 18 (manufactured by Kuraray Co., Ltd.), Isoban (registered trademark) # 04 (manufactured by Kuraray Co., Ltd.), and ammonia-modified Isovan (registered trademark) # 104. (Made by Kuraray Co., Ltd.), Ammonia-modified Isoban (registered trademark) # 110 (Made by Kuraray Co., Ltd.), Imidized Isoban (made by Kuraray Co., Ltd.) # 304 (Made by Kuraray Co., Ltd.) (Made by company Kurare) and so on. If necessary, a water-soluble polyvalent epoxy compound can be used as the cross-linking agent to be mixed with the maleic anhydride-isobutylene copolymer. Examples of the water-soluble polyvalent epoxy compound include Denacol EX-521 (manufactured by Nagase ChemteX Corporation), Tetrad (registered trademark) -C (manufactured by Mitsubishi Gas Chemical Company, Inc.) and the like. Further, as the adhesive, known adhesives other than polyvinyl alcohol adhesives such as urethane adhesives, acrylic adhesives, and epoxy adhesives can also be used. Further, for the purpose of improving the adhesive strength of the adhesive or improving the water resistance, additives such as zinc compounds, chlorides and iodides may be contained in the adhesive at a concentration of about 0.1 to 10% by weight. it can. Additives are also not limited. A polarizing plate is obtained by attaching a transparent protective layer to at least one surface of a polarizing element with an adhesive and then drying or heat-treating at an appropriate temperature.

In some cases, when the polarizing plate is attached to a display device such as a liquid crystal display device or an organic electroluminescence display device, the viewing angle is improved and / or contrast is improved on the surface of the transparent protective layer which becomes an unexposed surface after the attachment. Various functional layers for improvement, layers or films having brightness improving properties can also be provided. It is preferable to use an adhesive to attach the polarizing plate to these layers or films or a display device.

The polarizing plate may be provided with various known functional layers such as an antireflection layer, an antiglare layer, and a hard coat layer on the other surface of the transparent protective layer, that is, an exposed surface. .. A coating method is preferable for producing these various functional layers, but a method of laminating a film having that function via an adhesive or an adhesive can also be used. Further, the functional layer may be a layer or a film for controlling the phase difference.

As described above, the polarizing plate of the present invention is a polarizing plate including a polarizing element containing a base material and an azo compound and a transparent protective layer provided on at least one surface of the polarizing element, and has the general formula as the azo compound. By using the azo compound represented by (1), it has excellent polarization performance.

The polarizing element and the polarizing plate of the present invention can be used in a display device such as a liquid crystal display device. The display device using the polarizing element or the polarizing plate of the present invention is a display device having high contrast.

Further, the polarizing element and the polarizing plate of the present invention are provided with a protective layer or a functional layer, a support, etc., respectively, as necessary, and a liquid crystal projector, a calculator, a clock, a notebook computer, a word processor, a liquid crystal television, a polarizing lens, a polarized glasses, It is used for car navigation, organic electroluminescence displays, indoor and outdoor measuring instruments and indicators.

As a method of applying the polarizing plate of the present invention, the polarizing plate of the present invention may be attached to a support and used as a polarizing plate with a support. Since a polarizing plate is attached to the support, it is preferable that the support has a flat surface portion. Further, as the support, a glass molded product is preferable because it is used for optics. Examples of the glass molded product include a glass plate, a lens, a prism (for example, a triangular prism, a cubic prism, etc.) and the like. A lens having a polarizing plate attached can be used as a condenser lens with a polarizing plate in a liquid crystal projector. Further, a prism to which a polarizing plate is attached can be used as a polarizing beam splitter with a polarizing plate or a dichroic prism with a polarizing plate in a liquid crystal projector. Further, the polarizing plate may be attached to the liquid crystal cell. Examples of the material of the glass molded product include inorganic glass such as soda glass, borosilicate glass, crystal and sapphire, and organic plastic such as acrylic resin and polycarbonate, but inorganic glass is preferable. .. The thickness and size of the glass plate may be a desired size. Further, in a polarizing plate with a support having a support made of glass, an antireflection layer (AR layer) is provided on one or both of the glass surface and the polarizing plate surface in order to further improve the single plate light transmittance. Is preferable. A transparent adhesive (adhesive) is applied to the surface of such a support, for example, the surface of a flat surface of the support, and then the polarizing plate of the present invention is attached to the coated surface. Alternatively, a transparent adhesive (adhesive) may be applied to the polarizing plate, and then a support may be attached to the coated surface. As the adhesive (adhesive) used here, for example, an acrylic ester-based adhesive is preferable. When this polarizing plate is used as an elliptical polarizing plate in combination with a retardation plate, the retardation plate side of the elliptical polarizing plate is usually attached to a support, but the polarizing plate side of the elliptical polarizing plate is supported. You may attach it to your body.

[Display device]
The display device of the present invention includes the polarizing element of the present invention or the polarizing plate of the present invention. Further, the display device of the present invention is, for example, a reflective type, a transmissive type, or a transmissive / reflective type including a liquid crystal cell and a polarizing element of the present invention or a polarizing plate of the present invention arranged on one side or both sides of the liquid crystal cell. It can be a liquid crystal display device such as a mold. The liquid crystal cell is arbitrary, and is of an appropriate type such as an active matrix-driven liquid crystal cell represented by a thin film transistor type, a simple matrix-driven liquid crystal cell represented by a twist nematic type or a super twist nematic type, and the like. A liquid crystal cell may be used.

Further, in the display device of the present invention, one or two or more appropriate other optical members such as a prism array sheet, a lens array sheet, a light diffusing plate, and a backlight can be arranged at appropriate positions. When the polarizing element of the present invention, the polarizing plate of the present invention, or another optical member is provided, they may be the same on both sides or different on both sides.

The display device of the present invention may also have an adhesive layer for adhering to another member such as a liquid crystal cell on one side or both sides of the polarizing element of the present invention or the polarizing plate of the present invention. An appropriate adhesive substance or adhesive can be used to form the adhesive layer, and there is no particular limitation. Examples of the constituent materials of the adhesive layer include those using an appropriate polymer such as acrylic resin, silicone resin, polyester, polyurethane, polyamide, polyether, fluororesin, and rubber as a base polymer.

The display device of the present invention includes all liquid crystal display devices such as a twisted nematic system (TN), a super twisted nematic system (STN), a thin film transistor system (TFT), a vertical alignment system (VA), and an inplane switching system (IPS). It can be used for other display devices.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. The transmittance, degree of polarization, and contrast value of the polarizing elements and the polarizing plates obtained in Examples and Comparative Examples were measured as follows.

[Measurement method of transmittance and degree of polarization of polarizing element]
The transmittance at each wavelength of one polarizing element is the single transmittance Ts, and the transmittance at each wavelength when two polarizing elements are stacked so that their absorption axis directions are the same is the parallel transmittance Tp. The transmittance at each wavelength when two polarizing elements were stacked so that their absorption axes were orthogonal to each other was defined as the orthogonal position transmittance Tc. The respective transmittances Ts, Tp, and Tc were measured at each wavelength at 5 nm intervals using a spectrophotometer (“U-4100” manufactured by Hitachi High-Technologies Corporation).

The degree of polarization ρ (%) of the polarizing element was calculated from the parallel position transmittance Tp and the orthogonal position transmittance Tc by the following formula.
ρ = {(Tp-Tc) / (Tp + Tc)} ^1/2 x 100

[Measurement method of polarizing plate transmittance, polarization degree, and contrast value]
The transmittance of one polarizing plate corrected for visual sensitivity at each wavelength is the single transmittance Ys, and the transmittance at each wavelength when two polarizing plates are stacked so that their absorption axis directions are the same. The transmittance corrected for the parallel position Yp and the transmittance at each wavelength when two polarizing plates are stacked so that their absorption axes are orthogonal to each other are defined as the orthogonal position transmittance Yc. .. Luminous efficiency correction was performed by a C light source 2 ° field of view and a chromaticity function based on JIS Z 8722: 2009. The respective transmittances Ys, Yp, and Yc were measured at each wavelength at 5 nm intervals using a spectrophotometer (“U-4100” manufactured by Hitachi High-Technologies Corporation).

The degree of polarization Py (%) of the polarizing plate was calculated by the following formula (16) from the luminous efficiency-corrected parallel transmittance Yp and the luminous efficiency-corrected orthogonal transmittance Yc.
Py = {(Yp-Yc) / (Yp + Yc)} ^1/2 x 100 ... (16)

The contrast value (CR) of the polarizing plate was calculated by the following formula (17) from the luminous efficiency-corrected parallel-position transmittance Yp and the luminous-sensitivity-corrected orthogonal-position transmittance Yc.
CR = Yp / Yc ... (17)

で表されるモノアゾアミノ化合物２９．７重量部を得た。[Example 1]
<Synthesis of azo compound of Compound Example 1>
Add 25.3 parts by weight of 4-aminobenzene-1,3-disulfonic acid to 500 parts by weight of water, cool and add 31.3 parts by weight of a 35% by weight hydrochloric acid aqueous solution at 10 ° C. or lower, and then add sodium nitrite 6 by weight. .9 parts by weight was added, and the mixture was stirred at 5 to 10 ° C. for 1 hour to diazotize. To this, 10.7 parts by weight of 3-methylaniline dissolved in a dilute aqueous hydrochloric acid solution was added as a primary coupler (coupling component), and while stirring at 10 to 30 ° C., sodium carbonate was added to adjust the pH to 3, and the mixture was further stirred. The coupling reaction is completed, filtered, and the following structural formula (18)

29.7 parts by weight of the monoazoamino compound represented by is obtained.

で表されるジスアゾアミノ化合物３１．３重量部を得た。The obtained monoazoamino compound of the structural formula (18) was added to 400 parts by weight of water, dissolved in sodium hydroxide, 25.0 parts by weight of a 35 wt% hydrochloric acid aqueous solution at 10 to 30 ° C., and then sodium nitrite 5. .5 parts by weight was added, and the mixture was stirred at 20 to 30 ° C. for 1 hour to diazotize. As a secondary coupler, 8.6 parts by weight of 3-methylaniline dissolved in a dilute aqueous hydrochloric acid solution was added thereto, and while stirring at 20 to 30 ° C., sodium carbonate was added to adjust the pH to 3, and further stirring was performed to complete the coupling reaction. And filter, the following structural formula (19)

31.3 parts by weight of the disazoamino compound represented by is obtained.

で表されるトリスアゾアミノ化合物３２．６重量部を得た。The obtained dizoazoamino compound of the structural formula (19) was added to 250 parts by weight of water, dissolved in sodium hydroxide, 20.0 parts by weight of a 35 wt% hydrochloric acid aqueous solution at 20 to 30 ° C., and then sodium nitrite 4. .4 parts by weight was added, and the mixture was stirred at 20 to 30 ° C. for 1 hour to diazotize. As a tertiary coupler, 8.8 parts by weight of 2-methoxy-5-methylaniline dissolved in a dilute aqueous hydrochloric acid solution was added thereto, and while stirring at 20 to 30 ° C., sodium carbonate was added to adjust the pH to 3.5, and the mixture was further stirred. The coupling reaction is completed, filtered, and the following structural formula

A trisazoamino compound represented by 32.6 parts by weight was obtained.

The obtained trisazoamino compound of the structural formula (20) was added to 200 parts by weight of water, dissolved in sodium hydroxide, 16.0 parts by weight of a 35% aqueous hydrochloric acid solution at 20 to 30 ° C., and then sodium nitrite 3. .5 parts by weight was added, and the mixture was stirred at 20 to 30 ° C. for 1 hour to diazotize to obtain a diazodized trisazoamino compound. As a quaternary coupler, 16.1 parts by weight of 6-phenylamino-1-naphthol-3-sulfonic acid was added to 50 parts by weight of water and dissolved in sodium carbonate as weakly alkaline to obtain a solution of the quaternary coupler. ..

The previously obtained diazozate of the trisazoamino compound was injected into the solution of the fourth-order coupler while maintaining the pH at 8 to 10, and the mixture was stirred to complete the coupling reaction. Next, 30.5 parts by weight of monoethanolamine was added to an aqueous solution of 25 parts by weight of copper sulfate and reacted at 95 ° C. for 10 hours, and a copperization reaction was carried out until no unreacted substance was observed on thin layer chromatography. After the reaction, the mixture was salted out with sodium chloride and filtered to obtain 46.4 parts by weight of the azo compound (coplated tetrakisazo compound) of Compound Example 1 as an example of the azo compound represented by the general formula (1). ..

<Manufacturing of polarizing element>
A polyvinyl alcohol film (“VF-PE # 4000” manufactured by Kuraray Co., Ltd .; hereinafter simply referred to as “film”) having a saponification degree of 99 mol% or more and a film thickness of 40 μm as a base material is used in warm water at 35 ° C. It was immersed for 3 minutes and swelled. On the other hand, 1.0 part by weight of the azo compound of Compound Example 1 as the azo compound represented by the general formula (1) or a salt thereof, 1.0 part by weight of anhydrous sodium sulfate as a dyeing aid, and 2000 parts by weight of water. Was mixed to prepare an aqueous solution at 40 ° C. The swollen film was immersed in this aqueous solution at 40 ° C. to adsorb the azo compound on the film.

After washing the film on which the azo compound was adsorbed with water, boric acid treatment was carried out for 1 minute with an aqueous solution at 40 ° C. containing 2% by weight of boric acid. The film obtained by boric acid treatment was subjected to boric acid treatment for 5 minutes in an aqueous solution at 58 ° C. containing 3.0% by weight of boric acid while stretching 5.0 times. The film obtained by the boric acid treatment was washed with water at room temperature for 20 seconds while maintaining a tense state. The film obtained by the washing treatment was immediately dried at 60 ° C. for 5 minutes to obtain a film-shaped polarizing element having a film thickness of 15 μm. By the above method, a polarizing element containing an azo compound represented by the general formula (1) or a salt thereof according to an example of the present invention was produced.

[Example 2]
<Synthesis of azo compound of Compound Example 17>
As a quaternary coupler, instead of 16.1 parts by weight of 6-phenylamino-1-naphthol-3-sulfonic acid, (7,8-disulfo-2H-naphtho [1,2-d] triazole-2-yl- ) -1-naphthol-3-sulfonic acid 28.2 parts by weight is used, but the azo compound represented by the general formula (1) is the same as the synthesis of the azo compound of Compound Example 1 in Example 1. Alternatively, the azo compound (coplated tetrakisazo compound) of Compound Example 17 as a salt thereof was obtained.

<Manufacturing of polarizing element>
A polarizing element was produced in the same manner as in Example 1 except that the azo compound of Compound Example 17 was used instead of the azo compound of Compound Example 1.

[Comparative Example 1]
A polarizing element was produced in the same manner as in Example 1 except that the copperized azo compound described in Example 38 of JP-A-60-156759 was used instead of the azo compound of Compound Example 1. did.

[Comparative Example 2]
A polarizing element was produced in the same manner as in Example 1 except that the copperized azo compound described in Example 1 of Japanese Patent Publication No. 64-5623 was used instead of the azo compound of Compound Example 1. ..

Table 1 shows the single transmittance Ts, the parallel position transmittance Tp, the orthogonal position transmittance Tc, and the degree of polarization ρ at the wavelength having the highest degree of polarization in the polarizing elements of Examples 1 and 2 and the polarizing elements of Comparative Examples 1 and 2. The measurement result of is shown.

As can be seen from Table 1, the polarizing elements using the copperized azo compounds of Examples 1 and 2 of the present invention have the same transmittance as the copperized azo compounds known so far. It can be seen that the degree of polarization is dramatically improved.

[Example 3]
First, a polyvinyl alcohol film (“VF-PE # 4000” manufactured by Kuraray Co., Ltd .; hereinafter simply referred to as “film”) having a saponification degree of 99% or more and a film thickness of 40 μm as a base material is heated at 35 ° C. Was immersed in the film for 3 minutes and swelled. Further, 2.0 parts by weight of the azo compound of Compound Example 1 as the azo compound represented by the general formula (1) or a salt thereof, and Compound Example 20 as the azo compound represented by the general formula (3) or a salt thereof. 0.5 parts by weight of the azo compound (CI Direct Red 117) and the azo compound of Compound Example 111 as the azo compound represented by the general formula (4) or a salt thereof (International Publication No. 2007/138980) 0.5 parts by weight of the azo compound described in Example 1 of the above, 1.0 part by weight of sodium tripolyphosphate and 1.0 part by weight of anhydrous sodium sulfate as a dyeing aid, and 2000 parts by weight of water. An aqueous solution at 40 ° C. was prepared. The swollen film was immersed in this aqueous solution at 40 ° C. to adsorb the azo compound on the film.

After washing the film on which the azo compound was adsorbed with water, boric acid treatment was carried out for 1 minute with an aqueous solution at 30 ° C. containing 2% by weight of boric acid. The film obtained by boric acid treatment was subjected to boric acid treatment for 5 minutes in an aqueous solution at 58 ° C. containing 3.0% by weight of boric acid while stretching 5.0 times. The film obtained by the boric acid treatment was washed with water at room temperature for 20 seconds while maintaining a tense state. The film obtained by the washing treatment was immediately dried at 60 ° C. for 5 minutes to obtain a film-shaped polarizing element having a film thickness of 15 μm. By the above method, the azo compound represented by the general formula (1) or a salt thereof, the azo compound represented by the general formula (3) or a salt thereof, and the azo compound represented by the general formula (4) or a salt thereof. Was produced in the film.

An alkali-treated triacetyl cellulose film having a thickness of 80 μm (“TD-80U” manufactured by Fuji Photo Film Co., Ltd .; hereinafter abbreviated as “TAC”) was adhered to both sides of the obtained polarizing element with polyvinyl alcohol. By adhering with an agent, the film was laminated with a structure of TAC / adhesive layer / polarizing element / adhesive layer / TAC. As a result, a polarizing plate was obtained. The obtained polarizing plate was used as a measurement sample.

[Example 4]
As the azo compound represented by the general formula (1) or a salt thereof, 3.0 parts by weight of the azo compound of Compound Example 17 used in Example 2 was used instead of 2.0 parts by weight of the azo compound of Compound Example 1. Except for this, the azo compound represented by the general formula (1) or a salt thereof, the azo compound represented by the general formula (3) or a salt thereof, and the general formula (4) are represented in the same manner as in Example 3. A polarizing element containing the azo compound or a salt thereof in a film was prepared, and a polarizing plate was prepared, and the prepared polarizing plate was used as a measurement sample.

[Example 5]
As the azo compound represented by the general formula (3) or a salt thereof, the azo compound of Compound Example 20 is replaced with 0.5 parts by weight, and the sodium salt of the azo compound of Compound Example 41 (International Publication No. 2005/075572). The azo compound represented by the general formula (1) or a salt thereof, the general formula (3), in the same manner as in Example 3 except that 1.0 part by weight of the azo compound described in Example 1 was used. ), And the azo compound represented by the general formula (4) or a salt thereof are produced in a polarizing element, and a polarizing plate is prepared, and the prepared polarizing plate is used as a measurement sample. And said.

[Example 6]
As the azo compound represented by the general formula (3) or a salt thereof, the azo compound of Compound Example 20 is replaced with 0.5 parts by weight, and the azo compound of Compound Example 54 (International Publication No. 2012/108169, Example 3) Azo compound represented by the general formula (1) or a salt thereof in the same manner as in Example 3 except that 1.6 parts by weight of the azo compound represented by the formula (21) described in the above was used. , An azo compound represented by the general formula (3) or a salt thereof, and a polarizing element containing the azo compound represented by the general formula (4) or a salt thereof in a film, and a polarizing plate were prepared and prepared. The polarizing plate was used as a measurement sample.

[Example 7]
As the azo compound represented by the general formula (4) or a salt thereof, C.I. I. An azo compound represented by the general formula (1) or a salt thereof, generally used in the same manner as in Example 3 except that 0.58 parts by weight of Direct Orange 39 (CAS number: 1325-54-8) was used. A polarizing element containing the azo compound represented by the formula (3) or a salt thereof and the azo compound represented by the general formula (4) or a salt thereof in a film was produced, and a polarizing plate was produced and produced. Was used as a measurement sample.

[Example 8]
As the azo compound represented by the general formula (3) or a salt thereof, the azo compound of Compound Example 20 is replaced with 0.5 parts by weight, the azo compound of Compound Example 20 is 0.12 parts by weight, and the azo compound of Compound Example 99. Using 1.2 parts by weight of an azo compound (azo compound represented by the formula (17) described in Example 1 of International Publication No. 2012/108169) and azo represented by the general formula (4). As the compound or a salt thereof, C.I. I. An azo compound represented by the general formula (1) or a salt thereof, generally used in the same manner as in Example 3 except that 0.39 parts by weight of Direct Orange 39 (CAS number: 1325-54-8) was used. A polarizing element containing the azo compound represented by the formula (3) or a salt thereof and the azo compound represented by the general formula (4) or a salt thereof in a film was produced, and a polarizing plate was produced and produced. Was used as a measurement sample.

で表されるＣ．Ｉ．ダイレクト・イエロー２８を０．８０重量部使用したこと以外は、実施例３と同様にして、一般式（１）で表されるアゾ化合物又はその塩、一般式（３）で表されるアゾ化合物又はその塩、及びほぼ同じ波長にて偏光機能を持つ一般式（４）で表されるアゾ化合物又はその塩をフィルムに含有する偏光素子を作製すると共に偏光板を作製し、作製した偏光板を測定試料とした。[Example 9]
The following structural formula as another organic dye instead of 0.5 parts by weight of the azo compound of Compound Example 111 as the azo compound represented by the general formula (4) or a salt thereof.

Represented by C.I. I. The azo compound represented by the general formula (1) or a salt thereof, the azo compound represented by the general formula (3), in the same manner as in Example 3 except that 0.80 parts by weight of Direct Yellow 28 was used. Alternatively, a polarizing element containing the salt thereof and the azo compound represented by the general formula (4) having a polarization function at substantially the same wavelength or a salt thereof in the film was manufactured, and a polarizing plate was prepared, and the prepared polarizing plate was prepared. It was used as a measurement sample.

[Comparative Example 3]
A polarizing element was produced and a polarizing plate was provided in the same manner as in Example 3 except that the composition of the azo compound in Example 3 was changed to the composition of the azo compound described in Example 2 of JP-A-11-218611. It was prepared, and the prepared polarizing plate was used as a measurement sample.

[Comparative Example 4]
A polarizing element and a polarizing plate were produced in the same manner as in Example 3 except that the composition of the azo compound in Example 3 was changed to the composition of the azo compound described in Example 3 of Japanese Patent No. 4162334. The prepared polarizing plate was used as a measurement sample.

[Comparative Example 5]
A polarizing element and a polarizing plate were produced in the same manner as in Example 3 except that the composition of the azo compound in Example 3 was changed to the composition of the azo compound described in Example 1 of Japanese Patent No. 4360100. The prepared polarizing plate was used as a measurement sample.

[Comparative Example 6]
A polarizing element was produced and a polarizing plate was produced in the same manner as in Example 3 except that the azo compound of Compound Example 1, which is an azo compound represented by the general formula (1), was not used. The plate was used as a measurement sample.

[Comparative Example 7]
Instead of the azo compound of Compound Example 1, which is an azo compound represented by the general formula (1), it is represented by the formula (17) of International Publication No. 2012/108169, which is a tetrakisazo compound like the azo compound of Compound Example 1. A polarizing element was prepared and a polarizing plate was prepared in the same manner as in Example 3 except that 1.8 parts by weight of the azo compound was used, and the prepared polarizing plate was used as a measurement sample.

In Table 2, in the polarizing plates of Examples 3 to 9 and Comparative Examples 3 to 7, the single transmittance Ys corrected for the luminous efficiency at the wavelength having the highest degree of polarization, the parallel transmittance Yp corrected for the luminous efficiency, and the luminous efficiency are shown. The corrected orthogonal position transmittance Yc, the degree of polarization Py, and the contrast value CR are shown.

As can be seen from Table 2, the polarizing plates of Examples 3 to 9 of the present invention have improved polarization performance and contrast as compared with the polarizing plates of Comparative Examples 3 to 7. Further, even if the polarizing plates of Examples 3 to 9 were exposed to an environment of 85 ° C. and a relative humidity of 85% for 500 hours, the transmittance and the degree of polarization did not change.

From the above, as is clear from the results of Examples 1 to 9 and Comparative Examples 1 to 7, the polarizing plate and the polarizing element of the present invention have optical characteristics as compared with the conventional polarizing plate and the polarizing element. You can see that it is improving. Further, as is clear from the results of Examples 3 to 9 above, the polarizing plate and the polarizing element of the present invention can be seen to be highly durable polarizing elements and polarizing plates. In addition, products such as display devices and polarizing lenses using the polarizing element or polarizing plate of the present invention have good polarization characteristics and durability, so that high reliability can be obtained.

Claims (13)

The following general formula (1)

(In the formula, Ab ₁ represents a phenyl group having a substituent or a naphthyl group having a substituent, and Rb _{1 to Rb 5} independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and 1 to 1 carbon atoms. 4 alkoxy group, an alkoxy group having 1 to 4 carbon atoms and having a sulfo group, or a sulfo group, Xb ₁ is optionally substituted phenyl amino group, which may have a substituent Represents a benzoylamino group, a phenylazo group which may have a substituent, or a naphthotriazole group which may have a substituent.)
An azo compound represented by, or a salt thereof. The azo compound according to claim 1.
The following general formula (2)

(In the formula, Ab ₁ is a phenyl having one or two substituents selected from the group consisting of a sulfo group, a carboxy group, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. Represents a naphthyl group having 2 or 3 substituents selected from the group consisting of a group or a sulfo group, a hydroxy group, and an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and Rb _{1 to Rb 5 represent.} Each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and Xb ₁ is a methyl group or a methoxy group. , A phenylamino group, a hydroxy group, an amino group, which may have one or two substituents selected from the group consisting of a sulfo group, an amino group, and an alkylamino group having 1 to 4 carbon atoms. A benzoylamino group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an amino group, which may have one substituent selected from the group consisting of a carboxyethylamino group. , And a phenylazo group which may have 1 to 3 substituents selected from the group consisting of carboxyethylamino groups, or a naphthotriazole group substituted with 1 or 2 sulfo groups.)
An azo compound represented by, or a salt thereof. The azo compound according to claim 1 or 2.
_{One or two Xb 1} in the general formula (1) or (2) selected from the group consisting of a methyl group, a methoxy group, a sulfo group, an amino group, and an alkylamino group having 1 to 4 carbon atoms. An azo compound characterized by being a phenylamino group which may have a substituent of. A polarizing element comprising a base material and the azo compound according to any one of claims 1 to 3. The polarizing element according to claim 4.
The following general formula (3)

(In the formula, Ar ₁ represents a phenyl group having a substituent or a naphthyl group having a substituent, and Rr _{1 to Rr 6} independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and 1 to 1 carbon atoms. Represents an alkoxy group of 4 or an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and Xr ₁ is an amino group which may have a substituent, a phenylamino group which may have a substituent, or a substituent. It represents a benzoylamino group which may have a group, a phenylazo group which may have a substituent, or a naphthotriazole group which may have a substituent, and m and n are independently 0 or n, respectively. 1 is shown.)
A polarizing element further comprising an azo compound represented by (1) or a salt thereof. The polarizing element according to claim 4 or 5.
The following general formula (4)

(In the formula, Ay ₁ represents a sulfo group, a carboxy group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and Ry _{1 to Ry 4} are independent hydrogen atoms. , A sulfo group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and p represents an integer of 1 to 3).
A polarizing element further comprising an azo compound represented by (1) or a salt thereof. The polarizing element according to claim 5.
The azo compound represented by the general formula (3) or a salt thereof is the following general formula (5).

(In the formula, Ar ₁ is a phenyl having one or two substituents selected from the group consisting of a sulfo group, a carboxy group, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. Represents a naphthyl group having 2 or 3 substituents selected from the group consisting of a group or a sulfo group, a hydroxy group, and an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and Rr _{1 to Rr 6} are Each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and Xr ₁ is a methyl group or a methoxy group. , A phenylamino group, a hydroxy group, an amino group, which may have one or two substituents selected from the group consisting of a sulfo group, an amino group, and an alkylamino group having 1 to 4 carbon atoms. A benzoylamino group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an amino group, which may have one substituent selected from the group consisting of a carboxyethylamino group. , And a phenylazo group which may have 1 to 3 substituents selected from the group consisting of carboxyethylamino groups, or a naphthotriazole group substituted with 1 or 2 sulfo groups. And n independently indicate 0 or 1 respectively)
A polarizing element, which is an azo compound represented by the above or a salt thereof. The polarizing element according to claim 5 or 7.
_{One of Rr 5} and Rr ₆ in the general formula (3) or (5) is an alkoxy group having 1 to 4 carbon atoms, and the other is an alkyl group having 1 to 4 carbon atoms or an alkoxy having 1 to 4 carbon atoms. A polarizing element characterized by being a group. The polarizing element according to claim 5 or 7.
_{One or two Xr 1} in the general formula (3) or (5) selected from the group consisting of a methyl group, a methoxy group, a sulfo group, an amino group, and an alkylamino group having 1 to 4 carbon atoms. A phenylamino group which may have a substituent of, or a benzoylamino group which may have one substituent selected from the group consisting of a hydroxy group, an amino group, and a carboxyethylamino group. A polarizing element characterized by this. The polarizing element according to claim 6.
_{A polarizing element in which Ay 1} in the general formula (4) is a carboxy group or a sulfo group. The polarizing element according to any one of claims 4 to 10.
A polarizing element, wherein the base material is a film made of polyvinyl alcohol or a derivative thereof. The polarizing element according to any one of claims 4 to 11.
A polarizing plate including a transparent protective layer provided on at least one surface of the polarizing element. A display device comprising the polarizing element according to any one of claims 4 to 11 or the polarizing plate according to claim 12.