WO2020050333A1

WO2020050333A1 - Polarizing element, and polarizing plate, optical member and like each using said polarizing element

Info

Publication number: WO2020050333A1
Application number: PCT/JP2019/034840
Authority: WO
Inventors: 典明望月; 由侑服部; 光則中村; 貴大樋下田
Original assignee: 日本化薬株式会社; 株式会社ポラテクノ
Priority date: 2018-09-05
Filing date: 2019-09-04
Publication date: 2020-03-12
Also published as: JP7448477B2; CN112534316A; TW202014392A; TWI822850B; JPWO2020050333A1; KR20210057027A

Abstract

A polarizing element which contains an azo compound represented by formula (1) or a salt thereof, an azo compound represented by formula (2) or a salt thereof, and a base material. (In formula (1), Ar₁ represents a substituted phenyl group or a substituted naphthyl group; each of Rr₁-Rr₄ independently represents a hydrogen atom, a C1-4 alkyl group, a C1-4 alkoxyl group or a C1-4 alkoxyl group having a sulfo group; Xr₁ represents an optionally substituted amino group, an optionally substituted phenylamino group, an optionally substituted phenylazo group, an optionally substituted benzoyl group, an optionally substituted benzoylamino group or an optionally substituted naphthotriazole group; and m represents 0 or 1.) (In formula (2), Ab₁ represents a substituted phenyl group or a substituted naphthyl group; each of Rb₁-Rb₅ independently represents a hydrogen atom, a C1-4 alkyl group, a C1-4 alkoxyl group or a C1-4 alkoxyl group having a sulfo group; and Xb₁ represents an optionally substituted amino group, an optionally substituted phenylamino group, an optionally substituted phenylazo group, an optionally substituted benzoyl group, an optionally substituted benzoylamino group or an optionally substituted naphthotriazole group.)

Description

Polarizing element, polarizing plate and optical member using the same

The present invention relates to a dye-based polarizing element, a polarizing plate and an optical member using the same.

A polarizing element is generally manufactured by adsorbing and orienting a dichroic dye, iodine or a dichroic dye, on a base film such as a polyvinyl alcohol resin. A polarizing plate is manufactured by laminating a protective film made of triacetyl cellulose or the like on at least one surface of the polarizing element via an adhesive layer. The polarizing plate is used for a liquid crystal display device or 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. Among these, the dye-based polarizing plate is characterized by having high heat resistance, high heat and humidity durability, and high stability, and having high color selectivity by blending a dichroic dye.
Patent Documents 1 to 4 and Non-Patent Documents 1 and 2 disclose dye-based polarizing elements containing an azo compound.

JP-A-11-218611 JP 2001-033627 A JP 2004-251962 A JP 2004-075719 A JP 08-291259 A JP-A-2002-275381

An object of the present invention is to provide a polarizing element, a polarizing plate, an optical member, and the like (hereinafter, also referred to as “polarizing element, etc.”) having optical characteristics (polarization performance, contrast, etc.) equal to or better than those of the related art. It is in.

The present inventors have conducted intensive studies to solve the above problems, and as a result, have found that the optical characteristics of a polarizing element can be improved by combining two types of azo compounds having a specific structure. Was completed.

That is, the present invention relates to the following inventions 1 to 7, but is not limited thereto.
[Invention 1]
A polarizing element comprising an azo compound represented by the formula (1) or a salt thereof, an azo compound represented by the formula (2) or a salt thereof, and a substrate:

(In the formula (1), Ar ₁ represents a phenyl group having a substituent or a naphthyl group having a substituent, and Rr ₁ to Rr ₄ each independently represent a hydrogen atom, a C1-4 alkyl group, or a C1-4 alkoxyl group. Or a C1-4 alkoxyl group having a sulfo group, and Xr ₁ represents an amino group optionally having a substituent, a phenylamino group optionally having a substituent, a phenylazo group optionally having a substituent, A benzoyl group which may have a substituent, a benzoylamino group which may have a substituent or a naphthotriazole group which may have a substituent, and m represents 0 or 1);

(In the formula (2), Ab ₁ represents a phenyl group having a substituent or a naphthyl group having a substituent, and Rb ₁ to Rb ₅ each independently represent a hydrogen atom, a C 1-4 alkyl group, or a C 1-4 alkoxyl group. or an C1 ~ 4 alkoxyl group having a sulfo group, Xb ₁ is amino group which may have a substituent group, an optionally substituted phenylamino group, an optionally substituted phenylazo group A benzoyl group which may have a substituent, a benzoylamino group which may have a substituent or a naphthotriazole group which may have a substituent).
[Invention 2]
The azo compound represented by the formula (2) is represented by the formula (3)

(In the formula (3), Ab ₁ , Rb ₁ to Rb ₅ and Xb ₁ are the same as those described in the above formula (2))
The polarizing element according to invention 1, which is an azo compound represented by the formula:
[Invention 3]
The polarizing element according to invention 1 or 2, wherein Rb ₅ is a methoxy group.
[Invention 4]
Equation (4)

(In the formula (4), Ay ₁ represents a sulfo group, a carboxyl group, a hydroxyl group, a C1-4 alkyl group or a C1-4 alkoxyl group, and Ry ₁ to Ry ₄ each independently represent a hydrogen atom, a C1-4 alkyl group. Represents a group or a C1-4 alkoxyl group, and p represents 1, 2, or 3.)
4. The polarizing element according to any one of Inventions 1 to 3, further comprising an azo compound represented by the formula:
[Invention 5]
The polarizing element according to any one of Inventions 1 to 4, wherein the base material is a film containing a polyvinyl alcohol-based resin.
[Invention 6]
A polarizing plate, comprising: the polarizing element according to any one of Inventions 1 to 5; and a transparent protective layer provided on one or both surfaces of the polarizing element.
[Invention 7]
An optical member, device, or apparatus comprising the polarizing element according to any one of Inventions 1 to 5 or the polarizing plate according to Invention 6.

According to the present invention, a polarizing element or the like having excellent optical characteristics can be provided. In one embodiment, the polarizing element of the present invention has excellent durability (moisture resistance, heat resistance, and the like). In one embodiment, the polarizing element and the like of the present invention have good polarization performance and contrast, and can meet recent demands for high-definition displays. In one embodiment, the polarizing element or the like of the present invention has a high transmittance and a small change in the degree of polarization under a high-temperature and / or high-humidity environment recently required for a touch panel, an organic EL display, and the like.

において In the present specification, the term “azo compound” may be used to include a free form of an azo compound, a salt of the azo compound, a mixture of a free form (free acid or free base) and a salt, and the like. In the specification of the present application, a “substituent” includes a hydrogen atom for convenience.

<Polarizing element>
The polarizing element of the present invention includes a substrate, an azo compound represented by the above formula (1), and an azo compound represented by the above formula (2). When the azo compound represented by the formula (1) is the azo compound represented by the formula (3), a polarizing element having a higher degree of polarization can be realized. More preferably, the polarizing element of the present invention contains an azo compound represented by the formula (4) in addition to the azo compounds represented by the formulas (1) and (2). Thereby, a polarization element having a higher degree of polarization can be realized. That is, it is particularly preferable that the azo compound represented by each of the formulas (1), (2) and (4) is contained in the base material. When the azo compound used in the present invention has a functional group such as a hydroxyl group, a carboxyl group, and a sulfo group, it may be used as a free acid, or may be used as a salt, or a mixture of a free acid and a salt may be used. You may.

Examples of the salt of the azo compound include alkali metal salts such as lithium salt, sodium salt and potassium salt; alkaline earth metal salts such as calcium salt; ammonium salt; organic salts such as alkylamine salt and alkanolamine salt. The salt is preferably a lithium salt, a sodium salt, a potassium salt, or an ammonium salt, more preferably a lithium salt or a sodium salt, and further preferably a sodium salt.

In general, the azo compound can be synthesized by performing known diazotization and coupling according to known azo compound synthesis means known in the art (for example, page 626 of Non-Patent Document 1). . A polarizing element can be manufactured by dissolving an azo compound in a solution and impregnating the substrate in a dyeing step.

アゾ The azo compound represented by the above formula (1) will be described.

In the above formula (1), Ar ₁ represents a phenyl group having a substituent or a naphthyl group having a substituent.

When Ar ₁ is a phenyl group having a substituent, a sulfo group, a carboxyl group, a C1-4 alkyl group, a C1-4 alkoxy group, a C1-4 alkoxy group having a sulfo group, a nitro group, a benzoyl group, It preferably has at least one of an amino group, an acetylamino group and a C1-4 alkylamino group-substituted amino group, and more preferably has at least one sulfo group or carboxyl group. When the phenyl group has two or more substituents, at least one of the substituents is a sulfo group or a carboxyl group, and other substituents include a sulfo group, a carboxyl group, a C1-4 alkyl group, a C1-4 An alkoxyl group, a C1-4 alkoxyl group having a sulfo group, a nitro group, a benzoyl group, an amino group, an acetylamino group and a C1-4 alkylamino group-substituted amino group are preferable, and a sulfo group, a methyl group and an ethyl group are more preferable. Methoxy group, ethoxy group, carboxyl group, nitro group, benzoyl group and amino group, particularly preferably sulfo group, methyl group, methoxy group, ethoxy group, benzoyl group and carboxyl group. The C1-4 alkoxyl group having a sulfo group is preferably a straight-chain alkoxyl, and the substitution position of the sulfo group is preferably an alkoxyl terminal, more preferably a 3-sulfopropoxy group and a 4-sulfobutoxy group, and particularly preferably. Is a 3-sulfopropoxy group. The number of the sulfo groups in the phenyl group having a substituent is preferably 1 or 2, and the substitution position is not particularly limited. However, when the bond position with the CONH site in the formula (1) is the 1-position, the 4-position Only the combination of the 2- and 4-positions and the combination of the 3- and 5-positions are preferred.

In the above formula (1), when Ar ₁ is a naphthyl group having a substituent, the naphthyl group may be bonded at the 1-position to the CONH site or at the 2-position. Preferably, the naphthyl group is attached at its 2-position to the CONH site. The naphthyl group preferably has at least one of a sulfo group, a hydroxyl group, a carboxyl group, and a C1-4 alkoxy group having a sulfo group as a substituent, and more preferably has at least one sulfo group or a carboxy group. When the compound has two or more substituents, preferably, at least one of the substituents is a sulfo group, and the other substituents are selected from a sulfo group, a hydroxyl group, a carboxyl group, and a C1-4 alkoxyl group having a sulfo group. . The C1-4 alkoxyl group having a sulfo group is preferably a straight-chain alkoxyl group, and the substitution position of the sulfo group is preferably at the terminal of the alkoxyl group, more preferably a 3-sulfopropoxy group and a 4-sulfobutoxy group, and particularly preferably. Is a 3-sulfopropoxy group. When the number of the sulfo group which the naphthyl group having a substituent has as a substituent is 2, the position of the sulfo group on the naphthyl group is 4,8 when the bonding position with the CONH site is the 2nd position. Combinations and combinations at positions 6 and 8 are preferred, and combinations at positions 6 and 8 are more preferred. When the number of sulfo groups contained in the naphthyl group is 3, and when the bonding position with the CONH site in the formula (1) is position 2, the combination of the 3-, 6-, and 8-positions is preferably substituted as the sulfo group. Particularly preferred.

In the above formula (1), Rr ₁ to Rr ₄ each independently represent a hydrogen atom, a C1-4 alkyl group, a C1-4 alkoxyl group, or a C1-4 alkoxyl group having a sulfo group. Rr ₁ to Rr ₄ are each independently preferably a hydrogen atom, a C1-4 alkyl group or a C1-4 alkoxyl group, more preferably a hydrogen atom, a methyl group or a methoxy group. The C1-4 alkoxyl group having a sulfo group is preferably a straight-chain alkoxyl group, and the substitution position of the sulfo group is preferably an alkoxyl terminal, more preferably a 3-sulfopropoxy group and a 4-sulfobutoxy group. Preferably it is a 3-sulfopropoxy group.

Ｍ In the above formula (1), m represents 0 or 1. When m is 0, it becomes easy to produce a polarizing plate with little wavelength dependence, that is, a polarizing element or a polarizing plate having a neutral gray color, and when m is 1, a high degree of polarization is exhibited. one of.

In the above formula (1), Xr ₁ has an amino group which may have a substituent, a phenylamino group which may have a substituent, a phenylazo group which may have a substituent, Represents a benzoyl group which may be substituted, a benzoylamino group which may have a substituent or a naphthotriazole group which may have a substituent, and is preferably a phenylamino group which may have a substituent.

When Xr ₁ is a naphthotriazole group which may have a substituent, the naphthotriazole is 1,2-naphthotriazole or 2,3-naphthotriazole, preferably 2,3-naphthotriazole. The bonding position between Xr ₁ and the naphthyl group is not particularly limited, but is preferably the 2-position (central nitrogen atom) of the triazole ring.

The amino group optionally having a substituent is preferably a hydrogen atom, a hydroxy group, a carboxy group, a C1-4 alkyl group optionally having a sulfo group, and a C1-4 group optionally having a sulfo group. An amino group which may have one or two substituents selected from the group consisting of 4 alkoxyl groups, and more preferably a group consisting of a hydrogen atom, a methyl group, an ethyl group, a methoxy group, and an ethoxy group; An amino group which may have one or two substituents selected. The phenylamino group which may have a substituent is preferably a group consisting of a hydrogen atom, a C1-4 alkyl group, a C1-4 alkoxyl group, a sulfo group, an amino group, a hydroxyl group and a C1-4 alkylamino group. A phenylamino group optionally having one or two substituents selected from the group consisting of a hydrogen atom, a methyl group, a methoxy group, a sulfo group, and an amino group. A phenylamino group which may have one or two substituents; The phenylazo group which may have a substituent is preferably a group selected from the group consisting of a hydrogen atom, a hydroxy group, a C1-4 alkyl group, a C1-4 alkoxy group, an amino group and a carboxyethylamino group. It is a phenylazo group having three. The benzoyl group which may have a substituent is preferably a benzoyl group having one selected from the group consisting of a hydrogen atom, a hydroxyl group, a sulfo group, an amino group, and a carboxyethylamino group. The benzoylamino group optionally having a substituent is preferably a benzoylamino group having one selected from the group consisting of a hydrogen atom, a hydroxyl group, an amino group, and a carboxyethylamino group. The naphthotriazole group which may have a substituent preferably comprises a hydrogen atom, a hydroxy group, a carboxy group, a C1-4 alkyl group, a C1-4 alkoxy group, a sulfo group, an amino group, and a carboxyethylamino group. A naphthotriazole group having 1 to 3 groups selected from the group, and more preferably a naphthotriazole group having 1 to 3 sulfo groups. Xr ₁ is preferably a benzoylamino group optionally having a substituent or a phenylamino group optionally having a substituent, and more preferably a phenylamino group optionally having a substituent. . A phenylamino group which may have a substituent, a phenylazo group which may have a substituent, a benzoyl group which may have a substituent, or a benzoylamino group which may have a substituent. The position is not particularly limited, but when there is one substituent, it is substituted at the p-position with respect to the bonding position of the amino group, azo group, carbonyl group, or amide group bonded to the naphthalene ring in the above formula (1). Is particularly preferred. The substitution position in the naphthotriazole group which may have a substituent is not particularly limited, but when there is one substituent, the condensed ring position with the triazole ring is “1 and 2” or “2 and 3”. In the case of numbering, the 4- or 6-position of the naphthalene ring is preferred, and when there are two substituents, a combination of the 5- and 7-positions or a combination of the 6- and 8-positions is preferred (see the figure below). ).

方法 Examples of a method for obtaining the azo compound represented by the above formula (1) include the methods described in Patent Literature 5 and Patent Literature 6, but are not limited thereto.

さらなる Further specific examples of the azo compound represented by the above formula (1) are shown below.

アゾ The azo compound represented by the above formula (2) will be described.

In the above formula (2), Ab ₁ represents a phenyl group having a substituent or a naphthyl group having a substituent.

When Ab ₁ is a phenyl group having a substituent, the phenyl group is a sulfo group, a carboxyl group, a C1-4 alkyl group, a C1-4 alkoxy group, a C1-4 alkoxy group having a sulfo group, or a nitro group as a substituent. , A benzoyl group, an amino group, an acetylamino group and a C1-4 alkylamino group-substituted amino group, and more preferably at least one sulfo group or a carboxyl group. When the phenyl group has two or more substituents, at least one of the substituents is a sulfo group or a carboxyl group, and the other substituent is a sulfo group, a carboxyl group, a C1-4 alkyl group, a C1-4 alkoxyl group. A C1-4 alkoxyl group having a sulfo group, a nitro group, a hydroxyl group, an amino group or a substituted amino group (especially an acetylamino group or a C1-4 alkylamino group), and a sulfo group, a carboxyl group, methyl Group, ethyl group, methoxy group, ethoxy group, nitro group, hydroxyl group or amino group, more preferably sulfo group, carboxyl group, methyl group, ethyl group, methoxy group, ethoxy group, nitro group or amino group More preferably, a sulfo group, a carboxyl group, a methyl group, a methoxy group or Particularly preferably butoxy group. The other substituent is also preferably a sulfo group, a C1-4 alkyl group or a C1-4 alkoxyl group. Further, the C1-4 alkoxyl group having a sulfo group is preferably a linear alkoxyl group, and the substitution position of the sulfo group is preferably at the terminal of the alkoxyl group. As the C1-4 alkoxyl group having a sulfo group, a 3-sulfopropoxy group or a 4-sulfobutoxy group is more preferable, and a 3-sulfopropoxy group is particularly preferable. The number of substituents on the phenyl group having a substituent is preferably 1 or 2, and more preferably 2. The position of the substituent on the phenyl group is not particularly limited, but may be only 4-position with respect to the azo bond position in the above formula (2), a combination of 2-position and 4-position, or 3-position and 5-position. Is preferable, and a combination of the 2-position and the 4-position is particularly preferable.

In the above formula (2), when Ab ₁ is a naphthyl group having a substituent, the naphthyl group preferably has at least one sulfo group as a substituent, and the naphthyl group has two or more substituents. Preferably, at least one of these substituents is a sulfo group, and the other substituent is a C1-4 alkoxyl group having a sulfo group, a hydroxyl group, a carboxyl group or a sulfo group. Further, the C1-4 alkoxyl group having a sulfo group is preferably a linear alkoxyl group, and the substitution position of the sulfo group is preferably at the terminal of the alkoxyl group. As the C1-4 alkoxyl group having a sulfo group, a 3-sulfopropoxy group or a 4-sulfobutoxy group is more preferable, and a 3-sulfopropoxy group is particularly preferable. When the number of substitutions of the sulfo group on the naphthyl group having the substituent is 2, the substitution position of the sulfo group is defined by the 4-position and 8-position when the azo bond position in the above formula (2) is the 2-position. A combination or a combination of the 6th and 8th positions is preferred, and a combination of the 6th and 8th positions is particularly preferred. When the number of sulfo groups on the naphthyl group is 3, the sulfo group substitution position is particularly preferably a combination of the first, third, and sixth positions.

In the above formula (2), Xb ₁ has an amino group which may have a substituent, a phenylamino group which may have a substituent, a phenylazo group which may have a substituent, and a group which has a substituent. A benzoyl group, a benzoylamino group which may have a substituent or a naphthotriazole group which may have a substituent, and a benzoylamino group which may have a substituent, Is preferably a phenylamino group, a phenylazo group which may have a substituent, or a naphthotriazole group which may have a substituent, and a benzoylamino group which may have a substituent, It is more preferably a phenylamino group which may have, or a phenylazo group which may have a substituent, and particularly preferably a phenylamino group which may have a substituent.

The amino group preferably has one or two substituents. As the substituent, a hydrogen atom, a methyl group, a methoxy group, a sulfo group, an amino group, or a C1-4 alkylamino group is preferable.

The phenylamino group preferably has one or two substituents. As the substituent, a hydrogen atom, a C1-4 alkyl group, a C1-4 alkoxyl group, a hydroxyl group, a carboxyl group, a sulfo group, an amino group or a substituted amino group is preferable, and a hydrogen atom, a methyl group, a methoxy group, a sulfo group , An amino group or a substituted amino group is more preferable, and a hydrogen atom, a methyl group, a methoxy group, a sulfo group, an amino group, or a C1-4 alkylamino group is further preferable, and a hydrogen atom, a methoxy group, or an amino group is particularly preferable. .

The phenylazo group preferably has 1 to 3 substituents. As the substituent, a hydrogen atom, a C1-4 alkyl group, a C1-4 alkoxyl group, a hydroxyl group, a carboxyl group, a sulfo group, an amino group, or a substituted amino group is preferable, and a hydrogen atom, a hydroxy group, a carboxy group, a C1-4 A 4 alkyl group, a C1-4 alkoxyl group, an amino group, or a carboxyethylamino group is more preferable, and a hydrogen atom, a hydroxyl group, an amino group, a methyl group, a methoxy group, or a carboxyl group is more preferable. Particularly preferred.

The benzoyl group preferably has one substituent. As the substituent, a hydrogen atom, a C1-4 alkyl group, a C1-4 alkoxyl group, a hydroxyl group, a carboxyl group, a sulfo group, an amino group, or a substituted amino group is preferable, and a hydrogen atom, an amino group, a substituted amino group, or A hydroxyl group is more preferred, a hydrogen atom, an amino group or a carboxyethylamino group is still more preferred, and an amino group is particularly preferred.

The benzoylamino group preferably has one substituent. As the substituent, a hydrogen atom, a C1-4 alkyl group, a C1-4 alkoxyl group, a hydroxyl group, a carboxyl group, a sulfo group, an amino group, or a substituted amino group is preferable, and a hydrogen atom, an amino group, a substituted amino group, or A hydroxyl group is more preferred, a hydrogen atom, an amino group or a carboxyethylamino group is still more preferred, and an amino group is particularly preferred.

When Xb ₁ is a naphthotriazole group which may have a substituent, the naphthotriazole is 1,2-naphthotriazole or 2,3-naphthotriazole, and preferably 2,3-naphthotriazole. The bonding position between Xb ₁ and the naphthyl group is not particularly limited, but is preferably the 2-position (the central nitrogen atom) of the triazole ring. The naphthotriazole group preferably has 1 to 3 substituents, and more preferably has 2 substituents. As the substituent, a hydrogen atom, a hydroxy group, a carboxy group, a C1-4 alkyl group, a C1-4 alkoxy group, a sulfo group, an amino group, or a carboxyethylamino group is preferable, and a sulfo group is more preferable.

When Xb ₁ is a phenylamino group having a substituent, a phenylazo group having a substituent, a benzoyl group having a substituent, or a benzoylamino group having a substituent, and the number of substituents is one, the substituent is Is not particularly limited, but is preferably p-position with respect to the phenylamino group, the phenylazo group, the benzoyl group, or the amino group, azo group, carbonyl group, or amide group of the benzoylamino group. When Xb ₁ is a naphthotriazole group having a substituent, the position of substitution is not particularly limited, but when there is one substituent, the condensed position with the triazole ring is “1 and 2” or “2 and In the case of numbering as “3 position”, the 4 position or 6 position of the naphthalene ring portion is preferable, and when there are two substituents, the combination of 5 position and 7 position or the combination of 6 position and 8 position is preferable.

In the above formula (2), Rb ₁ to Rb ₅ each independently represent a hydrogen atom, a C1-4 alkyl group, a C1-4 alkoxyl group or a C1-4 alkoxyl group having a sulfo group, and a hydrogen atom, C1-4 It is preferably an alkyl group or a C1-4 alkoxyl group, more preferably a hydrogen atom, a methyl group or a methoxy group. The C1-4 alkoxyl group having a sulfo group is preferably a linear alkoxyl group, and the substitution position of the sulfo group is preferably at the terminal of the alkoxyl group. Preferred examples of the C1-4 alkoxy group having a sulfo group include a 3-sulfopropoxy group and a 4-sulfobutoxy group, with a 3-sulfopropoxy group being particularly preferred. Further, it is particularly preferable that Rb ₅ is a methoxy group, since the polarizing performance of the polarizing element is particularly improved.

When the azo compound represented by the above formula (2) is the azo compound represented by the above formula (3), the polarization performance of the polarizing element is further improved. In the above formula (3), Ab ₁ , Rb ₁ to Rb ₅ and Xb ₁ are the same as those described in the above formula (2).

には In order to further improve the optical characteristics of the polarizing element, the above formula (2) is preferably an azo compound represented by the following formula (5).

In the above formula (5), Ab ₁ , Rb ₂ , Rb ₄ and Xb ₁ are the same as those described in the above formula (2).

In the above formula (5), Rb ₂ and Rb ₄ each independently represent a hydrogen atom, a C1-4 alkyl group, a C1-4 alkoxyl group or a C1-4 alkoxyl group having a sulfo group, but a hydrogen atom, a methyl group Alternatively, it is preferably a methoxy group, more preferably a hydrogen atom or a methyl group. It is preferable that the azo compound represented by the above formula (2) has a structure represented by the above formula (5), because the polarization characteristics can be particularly improved.

The azo compounds represented by the above formulas (2), (3) and (5) can be prepared, for example, by a synthesis method described in Non-Patent Document 1, International Publication No. 2012/108169, or International Publication No. It can be synthesized by performing diazotization and coupling described in 2012/108173 and the like. The method for synthesizing the azo compounds represented by the above formulas (2), (3) and (5) is not limited to the method described in the above-mentioned literature. The azo compounds represented by the above formulas (2), (3) and (5) can be treated with copper sulfate or the like to form a copper complex salt compound.

具体 Specific examples of the azo compound represented by the above formula (2) are shown below. In addition, in the following compound examples, the sulfo group and the hydroxyl group are represented in the form of a free acid, but may be in the form of a salt.

In the above polarizing element, the content of the azo compound represented by the above formula (2) is in the range of 10 to 5000 parts by weight based on 100 parts by weight of the azo compound represented by the above formula (1). And more preferably in the range of 20 to 3000 parts by weight.

The polarizing element may further include the formula (4).

Examples of the method of synthesizing the azo compound represented by the above formula (4) include the synthesis method described in Non-Patent Document 1 and the method described in WO 2007/138980. It is not limited.

アゾ As the azo compound represented by the above formula (4), for example, C.I. I. Direct Yellow 12, C.I. I. Direct Yellow 72, C.I. I. Direct Orange 39 (CAS No .: 1325-54-8), azo compounds described in WO 2007/138980, and the like, but are not limited thereto.

具体 Specific examples of the azo compound represented by the above formula (4) are shown below. In the following compound examples, the sulfo group and the carboxyl group are represented in the form of a free acid, but the sulfo group and the carboxyl group may be in the form of a salt.

In the above polarizing element, the content of the azo compound represented by the above formula (4) is in the range of 1 to 1,000 parts by weight based on 100 parts by weight of the azo compound represented by the above formula (1). And more preferably in the range of 5 to 800 parts by weight.

In the above polarizing element, other organic dyes (especially azo compounds) other than the azo compounds represented by the above formulas (1), (2) and (4), for example, according to color adjustment, etc. 2 or more in combination with the azo compounds represented by the above formulas (1) and (2) or in the above formulas (1), (2) and (4). You may use together with the azo compound represented respectively. The other organic dye used in combination is not particularly limited, but is capable of dyeing a hydrophilic polymer and differs from the absorption wavelength region of the azo compound represented by the above formula (1) or (2). Dyes having light absorption in the wavelength region and having high dichroism are preferred. Specific examples of other organic dyes include, for example, azo compounds 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. Azo compounds such as Direct Violet 9; These azo compounds are used in the form of a free acid or in the form of a salt such as an alkali metal salt (for example, a sodium salt, a potassium salt, a lithium salt), an ammonium salt, and a salt of an amine. If necessary, when other organic dyes are used in combination, the intended polarizing element is a more neutral color polarizing element, a polarizing element having a characteristic color, a liquid crystal projector color polarizing element and other color polarizing elements. Depending on the type, the type of the other organic dye to be mixed can be changed. The compounding amount of the other organic dyes (the total compounding amount in the case of two or more kinds) is not particularly limited, but generally, the above formulas (1), (2) and (2) The amount is preferably in the range of 0.1 to 1000 parts by weight based on 100 parts by weight of the total amount of the azo compounds represented by (4).

親水 As the base material, a hydrophilic polymer is preferable. The hydrophilic polymer is not particularly limited, and includes, for example, polyvinyl alcohol or a derivative thereof, an amylose-based resin, a starch-based resin, a cellulose-based resin, a polyacrylate-based resin, and the like. As the substrate, polyvinyl alcohol or a derivative thereof (hereinafter, referred to as “polyvinyl alcohol-based resin”) is most preferable from the viewpoints of dyeability, resin crosslinkability, and the like. The polarizing element can be produced by forming the base material into a film shape, adsorbing the azo compound and other compounds on the film shape base material, and applying an orientation treatment such as stretching.

方法 The method for producing the polyvinyl alcohol-based resin is not particularly limited, and a known production method can be employed. The polyvinyl alcohol resin can be produced, for example, by saponifying a polyvinyl acetate resin (a homopolymer or a copolymer of vinyl acetate). Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer of another monomer copolymerizable with vinyl acetate. Examples of copolymers of other monomers copolymerizable with vinyl acetate include copolymers of unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids. The polyvinyl alcohol resin may be modified, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes.

The saponification degree of the polyvinyl alcohol-based resin is not limited, but the productivity is remarkable due to elution of the polyvinyl alcohol-based resin, in-plane unevenness of optical characteristics, reduction in dyeability in the dyeing step, or induction of cutting in the stretching step. From the viewpoint of preventing a decrease, 85% or more is usually preferable, 95% or more is more preferable, 99% or more is further preferable, and 99.5% or more is particularly preferable.

The degree of polymerization of the polyvinyl alcohol-based resin is not limited, but from the industrial viewpoint of preventing the productivity from being reduced by the fact that the polyvinyl alcohol-based resin is hardened or the film formability or the stretchability is reduced, it is 10,000 or less. Preferably, there is. In order to improve the optical characteristics of the polarizing element, the degree of polymerization of the polyvinyl alcohol-based resin is preferably from 1,000 to 10,000, more preferably from 2,000 to 10,000, further preferably from 3,500 to 10,000. Preferably, it is particularly preferably from 5,000 to 10,000. The polymerization degree of the polyvinyl alcohol-based resin indicates a viscosity average polymerization degree, and can be determined by a method well known in the art.

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

{Circle over (1)} First, a film of the polyvinyl alcohol-based resin is obtained by forming a film of the polyvinyl alcohol-based resin. As a method for forming a polyvinyl alcohol-based resin, a method of melt-extruding a water-containing 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), a gel film forming method (A method of once cooling and gelling an aqueous solution of a polyvinyl alcohol-based resin and then extracting and removing the solvent), a cast film forming method (a method of flowing an aqueous solution of a polyvinyl alcohol-based resin on a substrate, and drying), and a combination thereof. Although methods can be adopted, the present invention is not limited to these methods.

When a solvent is used during the film formation, the solvent is not particularly limited, and examples thereof include dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene glycol, glycerin, propylene glycol, and diethylene glycol. , Triethylene glycol, tetraethylene glycol, trimethylolpropane, ethylenediamine, diethylenetriamine, water and the like. The solvent may be used singly or as a mixture of two or more. The amount of the solvent used for film formation is not limited, but the viscosity of the film forming stock solution becomes high, so that filtration and defoaming at the time of preparation become difficult, and it becomes difficult to obtain a film raw material free of foreign matter and defects. From the viewpoint of preventing the occurrence, the content is preferably 70% by weight or more based on the entire film forming stock solution (mixed solution containing a polyvinyl alcohol-based resin and a solvent used for film forming). In addition, the viscosity of the stock solution is too low, making it difficult to control the desired thickness, and the effect of surface fluctuations due to the wind during drying increases, and the viewpoint of preventing the drying time from becoming longer and lowering productivity. Therefore, the amount of the solvent is preferably 95% by weight or less.

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

乾燥 Examples of a method for drying the film raw material after the film formation include, but are not limited to, drying with hot air, contact drying using 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 not particularly limited, but is preferably in the range of 50 to 70 ° C.

原 The film raw material after the drying is preferably subjected to a heat treatment in order to control the degree of swelling to a predetermined range described later. Examples of the heat treatment method include a method using hot air and a method in which a film roll is brought into contact with a hot roll, and are not particularly limited as long as they can be treated by heat. One of these methods may be used alone, or two or more of them 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 approximately 1 to 10 minutes, but is not particularly limited.

厚み The thickness of the raw film obtained in the above step is not limited, but is preferably 20 µm or more from the viewpoint of preventing the film from being easily broken. Further, the thickness is preferably 100 μm or less from the viewpoint of preventing the stress applied to the film at the time of stretching from being increased and the mechanical load in the stretching step from becoming large, and requiring a large-scale apparatus capable of withstanding the load. The thickness is more preferably from 20 to 80 μm, even more preferably from 20 to 60 μm.

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

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

The swelling degree F of the film raw material is not limited, but from the viewpoint of preventing the elongation at the time of stretching from remarkably lowering, increasing the possibility of breaking, and making it difficult to perform sufficient stretching, 180. % Or more, and more preferably 200% or more. Further, from the viewpoint of remarkably preventing wrinkles and sagging and cutting during stretching, the content is preferably 260% or less, more preferably 240% or less. It is more preferably from 200 to 240%, further preferably from 210 to 230%. In order to control the degree of swelling F, for example, a suitable degree of swelling F can be selected depending on the temperature and time when the film raw material after film formation is subjected to heat treatment.

The swelling degree F of the film raw material can be measured by a method well known in the art, for example, by the following method. First, a raw film is cut into 5 cm × 5 cm and immersed in 1 liter of distilled water at 30 ° C. for 4 hours. The immersed film is taken out of distilled water, sandwiched between two pieces of filter paper, and water droplets on the film surface are absorbed by the filter paper, and then the weight [β (g)] of the film immersed in water is measured. Further, the film that has been immersed and absorbed the 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 material is calculated by the following equation (v).

Swelling degree F = 100 × β / γ (%) (v)

染色 After the above steps, a dyeing step is performed. In the dyeing step, the azo compounds represented by the formulas (1) and (2) and, if necessary, other azo compounds (such as the azo compound represented by the formula (4) and the other organic dyes described above) (Hereinafter, also referred to as “azo compound of the formula (1)”) can be adsorbed on a polyvinyl alcohol-based resin film.

The dyeing step is not particularly limited as long as the method allows the azo compound of the formula (1) or the like to be adsorbed on the polyvinyl alcohol-based resin film. This is performed by immersing the base resin film. 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 for immersion in the solution can be adjusted appropriately, but is preferably adjusted for 30 seconds to 20 minutes, more preferably 1 to 10 minutes. As a dyeing method, a method of dipping a polyvinyl alcohol-based resin film in the above solution is preferable, but a method of applying the solution to a polyvinyl alcohol-based resin film may be used.

溶液 The solution containing the azo compound of the formula (1) or the like can contain sodium carbonate, sodium hydrogen carbonate, sodium chloride, sodium sulfate, anhydrous sodium sulfate, sodium tripolyphosphate, and the like as a dyeing aid. The content of the dyeing aid can be adjusted to any concentration depending on the dyeing time and temperature depending on the dyeability, but is preferably from 0 to 5% by weight, more preferably from 0.1 to 2% by weight.

洗浄 After the dyeing step, a washing step (hereinafter referred to as “washing step 1”) can be performed. The washing step 1 is a step of washing the dye solvent attached to the surface of the polyvinyl alcohol-based resin film in the dyeing step with a washing liquid. By performing the washing step 1, it is possible to prevent the dye from migrating into the solution to be processed next. In the washing step 1, water is generally used as a washing liquid. The specific step of the washing step 1 is not particularly limited, and a method of dipping in a washing liquid is preferable, but a method of applying the washing liquid to a polyvinyl alcohol-based resin film can also be used. The time required for the washing step 1 is not particularly limited, but is preferably 1 to 300 seconds, more preferably 1 to 60 seconds. The temperature of the cleaning solution 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.

の後 After the above-mentioned dyeing step or washing step 1, a step of including at least one kind of crosslinking agent and / or waterproofing agent in the polyvinyl alcohol-based resin film can be performed. Examples of the crosslinking agent include boric acid, boron compounds such as borax or ammonium borate, polyhydric aldehydes such as glyoxal or glutaraldehyde, polyvalent isocyanate compounds such as biuret type, isocyanurate type or block type, titanium Titanium-based compounds such as oxysulfate can be used, and ethylene glycol glycidyl ether, polyamide epichlorohydrin, and the like can be used. Boric acid is preferable. Examples of the water-proofing agent include succinic acid peroxide, ammonium persulfate, calcium perchlorate, benzoin ethyl ether, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, ammonium chloride and magnesium chloride.

上記 The crosslinking agent and / or the water-resistant agent used in the step of including the crosslinking agent and / or the water-resistant agent in the polyvinyl alcohol-based resin film is usually used in the form of a solution dissolved in a solvent. The solvent is preferably water, but is not limited. In this step, the concentration of the crosslinking agent and / or the water-proofing agent in the solution is preferably 0.1 to 6.0% by weight, and more preferably 1.0 to 4.0% by weight is more preferred. The temperature of the solution used in the step is preferably 5 to 70 ° C, more preferably 5 to 50 ° C. The method of including a crosslinking agent and / or a water-proofing agent in the polyvinyl alcohol-based resin film is preferably a method of dipping the polyvinyl alcohol-based resin film in a solution of the crosslinking agent and / or the water-proofing agent. A method of applying or applying to a resin film may be used. The time required for 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-proofing agent in the polyvinyl alcohol-based resin film, and when it is desired to shorten the manufacturing time of the polarizing element, or when cross-linking treatment or water-proofing treatment is unnecessary, etc. The step may be omitted.

延伸 After the dyeing step, after the washing step 1, or after the step of including the crosslinking agent and / or the waterproofing agent, a stretching step is performed. The stretching step is a step of uniaxially stretching the polyvinyl alcohol-based resin film. The stretching method may be either a wet stretching method or a dry stretching method. The present invention can be achieved if the stretching ratio is 3 times or more, but is preferably 5 to 7 times. The stretching step can be performed by one-stage stretching, but can also be performed by two or more stages of multi-stage stretching.

、 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 from room temperature to 180 ° C. Further, it is preferable to perform the stretching treatment in an atmosphere having a humidity of 20 to 95% RH. Specific examples of the stretching method include, but are not limited to, an inter-roll zone stretching method, a roll heating stretching method, a pressure stretching method, and an infrared heating stretching method.

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, and the polyvinyl alcohol-based resin film is dissolved in a solution containing the crosslinking agent and / or the water-resistant agent. It is preferable to perform a stretching treatment while immersing the film. As the cross-linking agent and / or water-proofing agent, those described above can be used, but boric acid or borax is preferable, and boric acid is particularly preferable. The polyvinyl alcohol resin film is stretched in a solution containing at least one or more crosslinking agents and / or water resistance agents. The concentration of the crosslinking agent and / or the waterproofing agent in the stretching step is, for example, preferably from 0.5 to 15% by weight, more preferably from 2.0 to 8.0% by weight. The stretching ratio is preferably 2 to 9 times, more preferably 5 to 8 times. The stretching temperature is preferably from 40 to 70 ° C, more preferably from 45 to 60 ° C. The stretching time is usually from 30 seconds to 20 minutes, but preferably from 1 to 5 minutes. The wet stretching step can be performed by one-stage stretching, but can also be performed by two or more stages of multi-stage stretching.

After performing the above-mentioned stretching step, a washing step of washing the film surface (hereinafter, referred to as “washing step 2”) is performed because the cross-linking agent and / or the water-proofing agent may precipitate or a foreign substance may adhere to the film surface. be able to. The time required for the washing step 2 is preferably 1 second to 5 minutes. As a washing method in the washing step 2, a method of dipping in a washing liquid is preferable, but a method of applying or applying the washing liquid to a polyvinyl alcohol-based resin film can also be used. The washing step 2 can be a single-stage process or a multi-stage process of two or more stages. The temperature of the cleaning solution used in the cleaning step 2 is not particularly limited, but is usually 5 to 50 ° C, preferably 10 to 40 ° C.

Examples of the solvent that can be used in each of the above steps include water; dimethyl sulfoxide; N-methylpyrrolidone; methanol, ethanol, propanol, isopropyl alcohol, glycerin, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and triethylene glycol. Examples include, but are not limited to, alcohols such as methylolpropane; and amines such as ethylenediamine or diethylenetriamine. Also, a mixture of two or more of these solvents can be used. The most preferred solvent is water.

の後 After the stretching step or the washing step 2, a drying step of the polyvinyl alcohol-based resin film is performed. In the drying step, natural drying can be adopted.However, in order to further increase the drying efficiency, water can be removed from the surface by compression using a roll, an air knife, a water absorption roll, or the like. Alternatively, air drying may be performed in place of the water removal. The temperature in the drying step is preferably from 20 to 100 ° C, more preferably from 60 to 100 ° C. The time required for the drying step can be in the range of 30 seconds to 20 minutes, but is preferably 5 to 10 minutes.

偏光 The polarizing element of the present invention can improve optical characteristics by using the azo compound represented by the formula (1) and the azo compound represented by the formula (2) together with the base material. In one embodiment, the polarizing element of the present invention has excellent durability.

<Polarizing plate>
The polarizing plate of the present invention includes the above-mentioned polarizing element, and a transparent protective layer provided on one or both sides of the polarizing element. The transparent protective layer can be provided as a coating layer of a transparent polymer or as a laminate 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. As the transparent polymer or transparent film used for the transparent protective layer, for example, cellulose acetate resin such as triacetyl cellulose or diacetyl cellulose or its film, acrylic resin or its film, polyvinyl chloride resin or its film, nylon resin or its Film, polyester resin or film thereof, polyarylate resin or film thereof, cyclic polyolefin resin or film thereof having a cyclic olefin such as norbornene as a monomer, polyethylene, polypropylene, cycloolefin or polyolefin having a norbornene skeleton or copolymer thereof, Examples include a polymer (or resin) having an imide and / or amide in the main chain or side chain or a film thereof. Further, as the transparent protective layer, a resin having liquid crystallinity 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 a 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.

接着 An adhesive can be used to attach the transparent protective layer to the polarizing element. The adhesive is not particularly limited, but is preferably a polyvinyl alcohol adhesive. Examples of the polyvinyl alcohol adhesive include Gohsenol (registered trademark) NH-26 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and Exevar (registered trademark) RS-2117 (manufactured by Kuraray Co., Ltd.). It is not limited. A crosslinking agent and / or a waterproofing 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 crosslinking agent can be further mixed as necessary. As the maleic anhydride-isobutylene copolymer, for example, Isovan (registered trademark) # 18 (manufactured by Kuraray Co., Ltd.), Isovan (registered trademark) # 04 (manufactured by Kuraray Co., Ltd.), and ammonia-modified Isoban (registered trademark) # 104 (Manufactured by Kuraray Co., Ltd.), ammonia-modified Isoban (registered trademark) # 110 (manufactured by Kuraray Co., Ltd.), imidized isoban (registered trademark) # 304 (manufactured by Kuraray Co., Ltd.), imidized isoban (registered trademark) # 310 (stock) Kuraray). If necessary, a water-soluble polyvalent epoxy compound can be used as a crosslinking agent mixed with the maleic anhydride-isobutylene copolymer. Examples of the water-soluble polyepoxy compound include Denacol EX-521 (manufactured by Nagase ChemteX Corporation) and Tetrad (registered trademark) -C (manufactured by Mitsubishi Gas Chemical Company, Ltd.). In addition, as the adhesive, a known adhesive other than the polyvinyl alcohol adhesive, such as a urethane adhesive, an acrylic adhesive, or an epoxy adhesive, may be used. Additives such as zinc compounds, chlorides and iodides may be included in the adhesive at a concentration of about 0.1 to 10% by weight for the purpose of improving the adhesive strength or the water resistance of the adhesive. . The additives are not limited. After attaching a transparent protective layer to one or both surfaces of the polarizing element with an adhesive, the polarizing element is dried or heat-treated at an appropriate temperature to obtain the polarizing plate.

When the polarizing plate is bonded to a display device such as a liquid crystal display device or an organic electroluminescence (organic light emitting diode) display device, the polarizing plate may be viewed on the surface of the transparent protective layer which becomes an unexposed surface after bonding. Various functional layers for improving the corner and / or the contrast, and a layer or a film having a luminance improving property may be provided. It is preferable to use an adhesive to attach the polarizing plate to these layers or films or a display device. Examples of the constituent material of the adhesive layer include acrylic resins, silicone resins, polyesters, polyurethanes, polyamides, polyethers, fluororesins, and those having a suitable polymer such as rubber as a base polymer, preferably An acrylic (co) polymer resin composition using an acrylic resin is exemplified. Techniques using the acrylic (co) polymer resin composition are described in JP-A-59-111114 and JP-A-4-254803. The techniques described are exemplified, but are not particularly limited.

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, on the exposed surface. . In order to produce these various functional layers, a coating method is preferable, but a method in which a film having the function is bonded via the above-mentioned adhesive or the above-mentioned pressure-sensitive adhesive can also be used. Further, the functional layer can be a layer or a film for controlling a retardation.

The present invention provides a polarizing element containing the azo compound represented by the formula (1) and the azo compound represented by the formula (2) together with a substrate, and a transparent protective layer provided on one or both surfaces of the polarizing element. By using the azo compound represented by the formula (1) and the azo compound represented by the formula (2) in the polarizing plate, the optical characteristics are improved. In one embodiment, the polarizing element of the present invention has excellent durability against light, heat, and humidity.

<Optical members etc.>
The polarizing element and the polarizing plate of the present invention can be used for an optical member, a device, or an apparatus (such as an optical member). The optical element or the like using the polarizing element or the polarizing plate of the present invention has high contrast. In one embodiment, the optical member or the like of the present invention has high durability and has the high contrast for a long time.

In addition, the polarizing element and the polarizing plate of the present invention are each provided with a protective layer or a functional layer, a support, and the like as necessary, and a liquid crystal projector, a calculator, a clock, a notebook computer, a word processor, a liquid crystal television, a polarizing lens, polarizing glasses, The present invention can be used for a head-up display, a car navigation system, an organic electroluminescence display, a display device used for indoor and outdoor measuring instruments and displays, or an optical device similar thereto.

として 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. The support preferably has a flat portion because a polarizing plate is attached thereto. Further, since the support is used for optical purposes, a glass molded product is preferable. Examples of the glass molded product include a glass plate, a lens, a prism (for example, a triangular prism, a cubic prism, and the like). For example, a lens having a polarizing plate attached thereto can be used as a condenser lens with a polarizing plate in a liquid crystal projector. Further, a prism having a polarizing plate attached thereto 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, a polarizing plate may be attached to the liquid crystal cell. As the material of the glass molded product, for example, soda glass, borosilicate glass, quartz, inorganic glass such as sapphire, acrylic resin, organic polymers such as polycarbonate, and the like, inorganic glass is preferable. . The thickness and size of the glass plate may be a desired size according to the purpose. In addition, a polarizing plate with a support having a support made of glass is provided with an antireflection layer (AR layer) on one or both of the glass surface and the polarizing plate surface in order to further improve single-plate light transmittance. Is preferred. In this case, a transparent adhesive (adhesive) is applied to the surface of the support, for example, to the surface of the flat portion of the support, and then the polarizing plate of the present invention is attached to the applied surface. Alternatively, a transparent adhesive (adhesive) may be applied to the polarizing plate, and then a support may be attached to the applied surface. The adhesive (adhesive) used here is preferably, for example, an acrylate ester-based adhesive. When this polarizing plate is used as an elliptically polarizing plate in combination with a retardation plate, the elliptically polarizing plate side of the elliptically polarizing plate is usually attached to a support, but the elliptically polarizing plate is supported on the polarizing plate side. It may be attached to the body.

表示 A display device provided with the polarizing element of the present invention or the polarizing plate of the present invention is also one embodiment of the present invention. One particularly preferable application of the polarizing plate of the present invention is a liquid crystal display device. The liquid crystal display device is, for example, a liquid crystal display including a liquid crystal cell and a polarizing element of the present invention or a polarizing plate of the present invention disposed on one side or both sides of the liquid crystal cell, such as a reflective type, a transmissive type, or a transmissive / reflective type. It can be a device. The use of the above liquid crystal cell is optional, for example, an appropriate liquid crystal cell of an active matrix drive type represented by a thin film transistor type, a simple matrix drive type liquid crystal cell represented by a twisted nematic type or a super twisted nematic type, or the like. A liquid crystal cell of a type may be used. The display device provided with the polarizing element or the polarizing plate of the present invention can provide not only a high degree of polarization, that is, a contrast, but also a high durability. The durability means that a display device which does not discolor and does not lower contrast even in an environment of 115 ° C. or 85 ° C. at a relative humidity of 85% is provided. When the contrast value is 100 or more and the degree of polarization is 98% or more, it is preferable as a display device. The contrast value is 1000 or more and the degree of polarization is more preferably 99% or more. The contrast value is 1100 or more. And it is very preferable that the degree of polarization is 99.9% or more.

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

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

The liquid crystal display device of the present invention is applicable to all liquid crystal display devices of a twisted nematic type (TN), a super twisted nematic type (STN), a thin film transistor type (TFT), a vertical alignment type (VA), an in-plane switching type (IPS) and the like. Can be used.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto. The evaluation of the transmittance, the degree of polarization, and the contrast value of the polarizing plates obtained in Examples and Comparative Examples was performed as follows.

(Method for measuring transmittance and degree of polarization of polarizing plate)
The transmittance at each wavelength of one polarizing plate is represented by a single transmittance Ts, and the transmittance at each wavelength when two polarizing plates are stacked so that their absorption axis directions are the same is the parallel transmittance Tp. When two polarizing plates are stacked so that their absorption axes are orthogonal to each other, the transmittance at each wavelength is the orthogonal transmittance Tc, and the single transmittance corrected for luminosity by the chromaticity function (C light source 2 ° visual field) Is Ys, the parallel position transmissivity corrected by the chromaticity function (C light source 2 ° visual field) is Yp, and the orthogonal position transmissivity corrected by the chromaticity function (C light source 2 ° visual field) is Yc. . The respective transmittances Ts, Tp, Tc, Ys, Yp and Yc were measured using a spectrophotometer (“U-4100” manufactured by Hitachi High-Technologies Corporation) at each wavelength of 5 nm.

The degree of polarization ρy (%) of the polarizing plate was determined from the parallel transmittance Yp corrected for visibility and the orthogonal transmittance Yc corrected for visibility by the following equation (6).

ρy (%) = {(Yp−Yc) / (Yp + Yc)} ^1/2 × 100 (6)

The contrast value CR was calculated from the parallel position transmittance Yp corrected for visibility and the orthogonal position transmittance Yc corrected for visibility by the following equation (7).

CR = Yp / Yc (7)

[Example 1]
<Preparation of polarizing element>
A polyvinyl alcohol film having a saponification degree of 99% or more and a film thickness of 60 μm (“VF-PE @ 6000” manufactured by Kuraray Co., Ltd .; hereinafter, simply referred to as “film”) was used as a substrate. It was immersed in warm water at 35 ° C. for 3 minutes to perform swelling treatment. As the azo compound represented by the above formula (1), Compound Example 1-3 of the present application (Japanese Patent Application Laid-Open No. 8-291259, 6.9 parts of 1-amino-2-methoxy-5-methylbenzene in Example 1 was replaced with 1-amino- 0.25 parts by weight of the azo compound represented by the above formula (2) as the azo compound of the present compound example 2-4 (International Publication No. 1.5 / 100 parts by weight of the azo compound of the formula (2) described in Compound Example 45 of 2012/108169) and the azo compound of the compound example 4-2 of the present application (international publication) as the azo compound represented by the above formula (4) A mixture of 0.14 parts by weight of the azo compound of the formula (2) described in Example 1 of 2007/138980, 2.0 parts by weight of sodium tripolyphosphate and 2,000 parts by weight of water was mixed at 45 ° C. An aqueous solution was prepared. The swelled film was immersed in the aqueous solution at 45 ° C., and the azo compounds were adsorbed on the film. The film on which each of the azo compounds was adsorbed was washed with water, and then immersed in a 40% aqueous solution containing 2% by weight of boric acid for 1 minute (boric acid treatment). The film obtained by the boric acid treatment was immersed in a 58 ° C. aqueous solution containing 3.0% by weight of boric acid for 5 minutes while being stretched 6.0 times (boric acid treatment). The film obtained by boric acid treatment was immersed in water at room temperature for 20 seconds while maintaining the tension state (washing treatment). The film obtained by the washing treatment was immediately dried at 60 ° C. for 5 minutes to obtain a polarizing element having a single transmittance of about 41% and a film thickness of 23 μm. By the above method, a polarizing element using a polyvinyl alcohol film containing the azo compounds represented by the formulas (1), (2) and (4) was produced.

<Preparation of polarizing plate>
An alkali-treated triacetyl cellulose film having a thickness of 80 μm (“TD-80U” manufactured by FUJIFILM Corporation; hereinafter abbreviated as “TAC”) was applied to both surfaces of the polarizing element obtained above with polyvinyl alcohol. By bonding using an adhesive, lamination was performed in a configuration of TAC / adhesive layer / polarizing element / adhesive layer / TAC. Thus, a polarizing plate was obtained. The obtained polarizing plate was used as a measurement sample.

[Example 2]
As the azo compound represented by the formula (2), instead of the azo compound of the compound example 2-4 of the present invention, the compound compound example 2-19 of the present invention (WO 2012/108169, (Obtained by changing 7.7 parts of 2,5-dimethylaniline used in the step of obtaining formula (71) from (70) to 9.7 parts of 2,5-dimethoxyaniline). A polyvinyl alcohol film containing the azo compounds represented by the above formulas (1), (2) and (4) was used in the same manner as in Example 1 except that the azo compound was used in parts by weight. A polarizing element having a single transmittance of about 41% and a film thickness of 23 μm was prepared, and a polarizing plate was prepared as a measurement sample.

[Example 3]
As the azo compound represented by the above formula (2), instead of the azo compound of the compound example 2-4 of the present invention, the compound example 2-13 of the present invention (WO 2012/108169, Obtained by changing 7.7 parts of 2,5-dimethylaniline used in the step of obtaining formula (71) from (70) to 9.7 parts of 2,5-dimethoxyaniline) 2.1 A polyvinyl alcohol film containing the azo compounds represented by the above formulas (1), (2) and (4) was used in the same manner as in Example 1 except that the azo compound was used in parts by weight. A polarizing element having a single transmittance of about 41% and a film thickness of 23 μm was prepared, and a polarizing plate was prepared as a measurement sample.

[Example 4]
As the azo compound represented by the formula (2), instead of the azo compound of the compound example 2-4 of the present invention, the compound example 2-17 of the present invention (WO 2012/108169, 7.7 parts of 2,5-dimethylaniline used in the step of obtaining the formula (71) from (70) was changed to 9.7 parts of 2,5-dimethoxyaniline, and 6-phenylamino- 1.45 parts by weight obtained by changing 16.1 parts of 1-naphthol-3-sulfonic acid to 17.6 parts of 6-[(4-hydroxyphenyl) azo] -1-naphthol-3-sulfonic acid) A polyvinyl alcohol film containing an azo compound represented by the above formula (1), formula (2) and formula (4) was used in the same manner as in Example 1 except that the azo compound of formula (1) was used. Simple Rate of about 41%, to produce a polarizing plate with making a polarizing element having a film thickness of 23 .mu.m, and a measurement sample.

[Example 5]
As the azo compound represented by the formula (2), instead of the azo compound of the compound example 2-4 of the present invention in Example 1, the compound example 2-25 of the present invention (WO 2012/108173, (Obtained by changing 7.7 parts of 2,5-dimethylaniline used in the step of obtaining formula (69) from (68) to 9.7 parts of 2,5-dimethoxyaniline) 1.9 A polyvinyl alcohol film containing the azo compounds represented by the above formulas (1), (2) and (4) was used in the same manner as in Example 1 except that the azo compound was used in parts by weight. A polarizing element having a single transmittance of about 41% and a film thickness of 23 μm was prepared, and a polarizing plate was prepared as a measurement sample.

[Example 6]
As the azo compound represented by the formula (1), instead of the azo compound of the compound example 1-3 of the present invention, the compound compound example 1-9 of the present invention (Japanese Unexamined Patent Application Publication No. 8-291259). Synthesized by changing .6 parts to 36.2 parts of 5-aminoisophthalic acid and changing 6.9 parts of 1-amino-2-methoxy-5-methylbenzene to 5.4 parts of 1-amino-5-methylbenzene The azo compounds represented by the above formulas (1), (2) and (4) were obtained in the same manner as in Example 1 except that 0.18 parts by weight of the azo compound was used. Using a polyvinyl alcohol film containing a compound, a polarizing element having a single transmittance of about 42% and a film thickness of 23 μm was prepared, a polarizing plate was prepared, and a measurement sample was prepared.

[Example 7]
As the azo compound represented by the above formula (1), instead of the azo compound of the compound example 1-3 of the present invention, the compound example 1-8 of the present invention (Japanese Unexamined Patent Publication No. 8-291259). 0.6 parts to 2,4-disulfoaniline 51.0 parts, and 1-amino-2-methoxy-5-methylbenzene 6.9 parts to aniline 4.7 parts, and further 1-hydroxynaphthalene 0.25-part azo compound obtained by changing 15.8 parts of 6-phenylamino-3-sulfonic acid to 12.7 parts of 1-hydroxynaphthalene-6-methylamino-3-sulfonic acid) In the same manner as in Example 1 except that the azo compound represented by the formula (1), the formula (2) and the formula (4) were used. Was about 41%, a polarizing element having a film thickness of 23 μm was fabricated, and a polarizing plate was fabricated to obtain a measurement sample.

Example 8
As the azo compound represented by the above formula (1), instead of the azo compound of the compound example 1-3 of the present invention, the compound example 1-17 of the present invention (International Publication No. 80) 39.8 parts of 6- (4-aminobenzoylamino) -4-hydroxynaphthalene-2-sulfonic acid used in the synthesis of 6- (4-aminobenzoylamino) -4-hydroxynaphthalene-2-sulfone 0.21 part of the azo compound obtained by changing the acid to 48.7 parts and changing the 3-methylaniline used in the synthesis of the formula (81) to 12.1 parts to aniline 10.5 parts) A polyvinyl alcohol film containing an azo compound represented by each of the above formulas (1), (2) and (4) was used in the same manner as in Example 1 except that Body transmittance of about 41%, to produce a polarizing plate with making a polarizing element having a film thickness of 23 .mu.m, and a measurement sample.

[Example 9]
As the azo compound represented by the above formula (1), instead of the azo compound of the compound example 1-3 of the present invention, the compound compound example 1-21 of the present invention (WO 2015/150026) The compound represented by the formula ( 82) 39.8 parts of 7- (4-aminobenzoylamino) -4-hydroxynaphthalene-2-sulfonic acid used in the synthesis of 6- (4-aminobenzoylamino) -4-hydroxynaphthalene-2-sulfone The acid was changed to 48.7 parts, the 12.5-part of 2,5-dimethylaniline used in the synthesis of the formula (83) was changed to 10.5 parts of aniline, and the 2,5 used in the synthesis of the formula (84) was changed. 9.7 parts of dimethylaniline is changed to 8.4 parts of aniline, and 17.7 parts of 7-phenylamino-4-hydroxynaphthalene-2-sulfonic acid is converted to 7- (4-aminobenzoic acid). Lamino) -4-hydroxynaphthalene-2-sulfonic acid (synthesized in place of 20.1 parts) except that 0.29 part of the azo compound was used, in the same manner as in Example 1, except that 0.29 part of the azo compound was used. (1) Using a polyvinyl alcohol film containing an azo compound represented by each of the formulas (2) and (4), a polarizing element having a unit transmittance of about 42% and a film thickness of 23 μm is prepared and a polarizing plate is used. Was prepared and used as a measurement sample.

[Example 10]
As the azo compound represented by the formula (4), 0.20 parts by weight of the azo compound described in Compound Example 4-1 of the present application was used instead of the azo compound of Compound Example 4-2 of the present invention in Example 1. Except for the above, in the same manner as in Example 1, the simplex transmittance was about 41% using a polyvinyl alcohol film containing the azo compounds represented by the above formulas (1), (2) and (4). In addition, a polarizing element having a film thickness of 23 μm and a polarizing plate were prepared, and used as a measurement sample. As the compound example 4-1 of the present application, a compound obtained by the following synthesis method was used. First, 10.8 parts of sulfanilic acid was added to 500 parts of water, and dissolved with sodium hydroxide. After cooling, at 10 ° C. or lower, 32 parts of 35% hydrochloric acid was added, followed by 6.9 parts of sodium nitrite, and the mixture was stirred at 5 to 10 ° C. for 1 hour. Thereto was added 20.9 parts of aniline-ω-methanesulfonic acid sodium salt, and the mixture was adjusted to pH 3.5 with sodium carbonate while stirring at 20 to 30 ° C. The mixture was further stirred to complete the coupling reaction, and filtered to obtain 17 parts of a monoazo compound. After dissolving 12 parts of the obtained monoazo compound and 21 parts of 4,4'-dinitrostilbene-2,2'-sulfonic acid in 300 parts of water, 12 parts of sodium hydroxide was added and a condensation reaction was carried out at 90 ° C. . Subsequently, the mixture was reduced with 9 parts of glucose, salted out with sodium chloride, and filtered to obtain 16 parts of an azo compound shown in Compound Example 4-1 of the present application.

[Example 11]
In place of the azo compound of Compound Example 4-2 of the present application in Example 1, C.I. I. Except that Direct Yellow 28 was used, in the same manner as in Example 1, the simplex transmittance using a polyvinyl alcohol film containing the azo compound represented by each of the above formulas (1) and (2) was obtained. A polarizing element having a thickness of about 41% and a film thickness of 23 μm was prepared, and a polarizing plate was prepared.

[Example 12]
In place of the azo compound of Compound Example 4-2 of the present application in Example 1, C.I. I. Except that Direct Orange 72 was used, in the same manner as in Example 1, the simplex transmittance using a polyvinyl alcohol film containing an azo compound represented by each of the above formulas (1) and (2) was obtained. A polarizing element having a thickness of about 41% and a film thickness of 23 μm was prepared, and a polarizing plate was prepared.

[Comparative Example 1]
Using the azo compound described in Example 2 of JP-A-11-218611, a polarizing element having a single transmittance of about 40% and a film thickness of 23 μm was manufactured, a polarizing plate was manufactured, and the manufactured polarizing plate was measured. A sample was used.

[Comparative Example 2]
Using the azo compound described in Example 3 of JP-A-2001-033627, a polarizing element having a single transmittance of about 41% and a film thickness of 23 μm was manufactured, a polarizing plate was manufactured, and the manufactured polarizing plate was measured. A sample was used.

[Comparative Example 3]
Using the azo compound described in Example 1 of JP-A-2004-251962, a polarizing element having a single transmittance of about 41% and a film thickness of 23 μm was prepared, a polarizing plate was prepared, and the prepared polarizing plate was measured. A sample was used.

[Comparative Example 4]
Instead of the azo compound of the compound example 1-3 of the example 1, the disazo dye C.I. of the same color is used so that the single transmittance can be adjusted to 41% by the dyeing time of the example 1. I. A polarizing element having a single transmittance of about 41% and a film thickness of 23 μm using a polyvinyl alcohol film containing an azo compound was prepared in the same manner as in Example 1 except that 0.2 parts by weight of Direct Red 81 was used. At the same time, a polarizing plate was prepared and used as a measurement sample.

[Comparative Example 5]
JP-B-64-5623, which is an azo compound exhibiting the same color blue so that the single-piece transmittance can be adjusted to 41% by the dyeing time of Example 1 in place of the azo compound of Compound Example 2-4 of Example 1 In the same manner as in Example 1 except that 0.2 parts by weight of the dye (azo compound) described in Example 1 of the official gazette was used, a single substance transmittance using a polyvinyl alcohol film containing an azo compound was about 41%. %, A polarizing element having a thickness of 23 μm was prepared, and a polarizing plate was prepared as a measurement sample.

<Evaluation of optical performance>
Table 1 shows the individual transmittances Ys (%), the parallel transmittances Yp (%), the orthogonal transmittances Yc (%), and the degrees of polarization ρy (%) in the polarizing plates of Examples 1 to 12 and Comparative Examples 1 to 5. ) And the measurement results of the contrast value CR.

分かる As can be seen from Table 1, the polarizing plates of Examples 1 to 12 of the present invention are polarizing plates having improved polarization performance and contrast as compared with polarizing plates using conventional azo compounds.

<Durability evaluation>
Next, changes in optical characteristics when the polarizing plates of Examples 1 to 12 and Comparative Examples 1 to 5 were held at 115 ° C. for 1000 hours and in an environment of a temperature of 85 ° C. and a humidity of 85% for 1000 hours were confirmed. . As a result, the polarizing plate of the present invention did not show a decrease in the contrast and the degree of polarization in an environment of 115 ° C., 85 ° C., and 85% RH.

As is clear from the results of Examples 1 to 12 and Comparative Examples 1 to 5, the polarizing element and the polarizing plate of the present invention have improved optical characteristics and durability. Therefore, by using the polarizing element or the polarizing plate, a liquid crystal display device having excellent polarization characteristics and high durability and a polarizing lens can be obtained.

The present invention can provide a polarizing element, a polarizing plate, an optical member, and the like having optical characteristics equivalent to or better than those of the related art. The polarizing element or the polarizing plate of the present invention can be used for a liquid crystal projector, a calculator, a clock, a notebook computer, a word processor, a liquid crystal television, a polarizing lens, polarizing glasses, a head-up display, a car navigation system, an organic electroluminescent display (commonly called an OLED), and indoor and outdoor. It can be used for a display device used for a measuring instrument or a display device, or an optical device similar thereto. A liquid crystal display device including the polarizing element of the present invention or the polarizing plate of the present invention is one embodiment of the present invention. Further, as one of particularly preferred uses of the polarizing plate of the present invention, a display device provided with the polarizing element or the polarizing plate of the present invention not only provides a high degree of polarization, that is, a contrast, but also provides high durability. I can do it. The durability means that a display device which does not discolor and does not lower contrast even in an environment of 115 ° C. or 85 ° C. at a relative humidity of 85% is provided. Particularly preferred applications are those used in fields requiring not only high contrast but also heat resistance, wet heat resistance, and light resistance, such as in-vehicle displays, liquid crystal projectors, head-up displays, and outdoor displays.

Claims

A polarizing element comprising an azo compound represented by the formula (1) or a salt thereof, an azo compound represented by the formula (2) or a salt thereof, and a substrate:

(In the formula (1), Ar 1 represents a phenyl group having a substituent or a naphthyl group having a substituent, and Rr 1 to Rr 4 each independently represent a hydrogen atom, a C1-4 alkyl group, or a C1-4 alkoxyl group. Or a C1-4 alkoxyl group having a sulfo group, and Xr 1 represents an amino group optionally having a substituent, a phenylamino group optionally having a substituent, a phenylazo group optionally having a substituent, A benzoyl group which may have a substituent, a benzoylamino group which may have a substituent or a naphthotriazole group which may have a substituent, and m represents 0 or 1);

(In the formula (2), Ab 1 represents a phenyl group having a substituent or a naphthyl group having a substituent, and Rb 1 to Rb 5 each independently represent a hydrogen atom, a C 1-4 alkyl group, or a C 1-4 alkoxyl group. or an C1 ~ 4 alkoxyl group having a sulfo group, Xb 1 is amino group which may have a substituent group, an optionally substituted phenylamino group, an optionally substituted phenylazo group A benzoyl group which may have a substituent, a benzoylamino group which may have a substituent or a naphthotriazole group which may have a substituent).
The azo compound represented by the formula (2) is represented by the formula (3)

(In the formula (3), Ab 1 , Rb 1 to Rb 5 and Xb 1 are the same as those described in the above formula (2))
The polarizing element according to claim 1, which is an azo compound represented by the following formula:
The polarizing element according to claim 1, wherein Rb 5 is a methoxy group.
Equation (4)

(In the formula (4), Ay 1 represents a sulfo group, a carboxyl group, a hydroxyl group, a C1-4 alkyl group or a C1-4 alkoxyl group, and Ry 1 to Ry 4 each independently represent a hydrogen atom, a C1-4 alkyl group. Represents a group or a C1-4 alkoxyl group, and p represents 1, 2, or 3.)
4. The polarizing element according to claim 1, further comprising an azo compound represented by the following formula:
(5) The polarizing element according to any one of (1) to (4), wherein the substrate is a film containing a polyvinyl alcohol-based resin.
A polarizing plate comprising: the polarizing element according to any one of claims 1 to 5; and a transparent protective layer provided on one or both surfaces of the polarizing element.
An optical member, apparatus, or device comprising the polarizing element according to any one of claims 1 to 5 or the polarizing plate according to claim 6.