WO2019117123A1

WO2019117123A1 - Polarizing element for visible region and infrared region, and polarizing plate

Info

Publication number: WO2019117123A1
Application number: PCT/JP2018/045447
Authority: WO
Inventors: 典明望月; 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: 2017-12-13
Filing date: 2018-12-11
Publication date: 2019-06-20
Also published as: JP2023052132A; TW201932542A; CN111448494B; CN114350175A; TWI783092B; JP2023040123A; CN111448494A; JPWO2019117123A1; JP7319195B2

Abstract

The present application provides a polarizing element containing a water-soluble compound that absorbs infrared rays or a salt thereof.

Description

Polarizers for visible and infrared regions, and polarizers

The present invention relates to a polarizing element, a polarizing plate and a liquid crystal display device containing a water-soluble compound or a salt thereof that absorbs light in the near infrared region.

In general, a polarizing film is manufactured by adsorbing and orienting a dichroic dye, iodine or a dichroic dye, to a polyvinyl alcohol resin film. A polarizing film using iodine as a dichroic dye is called an iodine-based polarizing film, while a polarizing film using a dichroic dye as a dichroic dye is called a dye-based polarizing film. A protective film made of triacetyl cellulose or the like is bonded to at least one surface of the polarizing film via an adhesive layer to form a polarizing plate, which is used for a liquid crystal display device or the like. An iodine-based polarizing plate made of an iodine-based polarizing film exhibits high transmittance and a high degree of polarization, that is, a high contrast, as compared with a dye-based polarizing plate made of a dye-based polarizing film. It is widely used in mobile phones, PDAs, etc. However, although an iodine-based polarizing plate is superior to a dye-based polarizing plate in terms of optical characteristics, it is inferior to a dye-based polarizing plate in terms of optical durability. For example, when the iodine-based polarizing plate is left under high temperature and humidity The decolorization causes problems such as an increase in the transmittance and a decrease in the degree of polarization. A polarizing plate having high transmittance and polarization degree, high contrast, and excellent heat resistance and moisture and heat resistance is required, and as an invention for this request, the transmittance and polarization degree are high, high contrast and environmental test For example, a polarizing plate which is also excellent in dry heat durability is required. Patents containing zinc as in Patent Documents 1 to 3 as inventions to this demand, polarizing plates obtained by processing with a triterpenoid glycoside as in Patent Document 4, and polyvalent materials as in Patent Document 5 There is a technology that improves the heat resistance by the aldehyde. However, there has not been obtained any plate that sufficiently meets the above-mentioned requirements, and there is a strong demand for high durability such as improvement of dry heat durability with respect to a polarizing plate that can be manufactured inexpensively and simply.

A general polarizing plate is a polarizing film such as a film of a stretched and oriented polyvinyl alcohol or a derivative thereof, or a film of a polyene produced by orientating a polyene by dehydrochlorination of a polyvinyl chloride film or dehydration of a polyvinyl alcohol film. The substrate is manufactured by dyeing or incorporating iodine or a dichroic dye as a polarizing element. Among these, an iodine-based polarizing film using iodine as a polarizing element is excellent in polarization performance but is weak against water and heat, and is durable when used for a long time under high temperature and high humidity. There was a problem, and it was not possible to control the transmittance to the infrared region. On the other hand, although a dye-based polarizing film using a dichroic dye as a polarizing element is superior in moisture resistance and heat resistance to an iodine-based polarizing film, it is a polarizing plate having a polarizing function with respect to wavelengths for visible wavelengths. It was not a polarizing plate capable of controlling the transmittance in the infrared wavelength range.

In recent years, in applications such as recognition light sources for touch panels, security cameras, sensors, forgery prevention, and communication devices, not only polarizing plates for visible wavelengths but also polarizing plates used in infrared regions are required. In response to such a demand, an infrared polarizing plate obtained by polyeneifying an iodine-based polarizing plate as in Patent Document 15, an infrared polarizing plate applying wire grit as in Patent Document 16 or 14 or a Patent Document 17 An infrared polarizer formed by stretching a glass containing fine particles, and a type using a cholesteric liquid crystal as described in Patent Document 18 or 6 have been reported. In patent document 15, durability is weak, heat resistance, wet heat durability, and light resistance are weak, and have not reached practicality. The wire grid type such as Patent Document 16 or 14 is in widespread use because it can be processed into a film type as well as being stable as a product. However, the surface should not be touched because the surface does not maintain the optical properties unless there is nano level unevenness, which limits the application to be used, and further anti-reflection and anti-glare processing Is difficult. The glass stretch type containing fine particles as in Patent Document 17 has high durability and high dichroism, and thus reaches practicality. However, since the glass itself is stretched while containing fine particles, the element itself is easily broken and fragile, and the flexibility as in the conventional polarizing plate is lost, so that surface processing and bonding with other substrates are difficult. There was a problem. The technology of reference 5 is a technology using circularly polarized light that has been published for a long time, but since the color changes depending on the viewing angle, and basically it is a polarizing plate using reflection, stray light And it was difficult to form absolutely polarized light. That is, there was no polarizing plate corresponding to an infrared wavelength region which is an absorption type polarizing element like a general polarizing plate, is flexible in film type, and has high durability.

Japanese Patent Application Laid-Open No. 61-175602 Japanese Patent Laid-Open No. 2003-50318 Japanese Patent Application Laid-Open No. 2003-29042 JP 2005-241689 A Japanese Patent Application Laid-Open No. 6-235815 Japanese Patent Application Laid-Open No. 2-167991 Japanese Patent Application Laid-Open No. 61-221264 Japanese Patent Application Publication No. 2006-508034 Japanese Patent Application Laid-Open No. 63-33477 International Publication No. 2013/035560 Japanese Patent Application Laid-Open No. 59-11385 JP, 2010-106248, A JP, 2001-181184, A JP, 2013-24982, A U.S. Pat. No. 2,494,686 JP, 2016-148871, A JP 2004-86100 A JP, 2013-64798, A JP, 2004-251962 A JP 2001-033627 A Japanese Patent Application Publication No. 2001-290029 JP, 2010-072548, A JP 2007-084803 A JP 2007-238888 A

The present invention has been made in view of the above circumstances, and an object thereof is to provide a novel polarizing element, a polarizing plate, and an optical device.

As a result of intensive studies to solve the above problems, the present inventor has developed a novel polarizing element containing a water-soluble compound or a salt thereof that absorbs light in the infrared region.

In one aspect, the polarizing element of the present invention comprises iodine.

In one aspect, a specific transmittance is set to produce the polarizing element of the present invention.

In one aspect, the polarizing element of the present invention contains a specific azo compound.

That is, the gist configuration of the present invention is as follows.
Invention 1
A polarizing element comprising at least one dichroic dye exhibiting polarization characteristics in the visible region, and a water-soluble compound or a salt thereof that absorbs light in the infrared region.
Invention 2
The polarizing element of the invention 1 whose water-soluble compound which absorbs the light of the said infrared region is an azo compound.
Invention 3
The polarizing element as described in the invention 2 whose said azo compound is an azo compound shown by following formula (1):

In the formula, Ai ₁ and Ai ₂ are each independently represented by a hydrogen atom, an azo group, or the following formula (2) (provided that both Ai ₁ and Ai ₂ are hydrogen atoms are excluded),
-NH- is bonded to both naphthalene rings at any position of the combination of a and a ', b and b', a and b ', b and a',

In the formula, the rings substituted by Ri ₁ are each independently a benzene ring when there is no ring represented by the broken line, and a naphthalene ring when there is a ring represented by the broken line ,
Ri ₁ each independently represents a chlorine atom, a sulfo group, a nitro group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms having a sulfo group, An alkyl group having 1 to 4 carbon atoms having a hydroxy group, an alkyl group having 1 to 4 carbon atoms having a carboxy group, an alkoxy group having 1 to 4 carbon atoms having a sulfo group, an alkoxy having 1 to 4 carbon atoms having a hydroxy group A C 1-4 alkoxy group having a group or a carboxy group,
Bi each independently represents a phenyl group which may have a substituent or a naphthyl group which may have a substituent, and the substituent is a hydrogen atom, a chlorine atom, a sulfo group, a nitro group, a hydroxy group, Alkyl group having 1 to 4 carbon atoms, alkoxy group having 1 to 4 carbon atoms, alkyl group having 1 to 4 carbon atoms having a sulfo group, alkyl group having 1 to 4 carbon atoms having a hydroxy group, carbon number having a carboxy group A C 1-4 alkoxy group having a 1-4 alkyl group, a sulfo group, a C 1-4 alkoxy group having a hydroxy group, or an C 1-4 alkoxy group having a carboxy group,
m is an integer of 1 to 3;
When Bi has a hydroxy group as a substituent, the hydroxy group can form —O—Cu—O— with the hydroxy group in the above formula (1) and a copper atom. )
Invention 4
The polarizing element according to any one of Inventions 1 to 3, wherein Formula (2) is represented by Formula (3):

In the formula, Ri ₁ is a substituted ring, Ri ₁ and m are respectively the same as in formula (2),
The oxygen atom represented by —O— bond forms —O—Cu—O— with —OH and copper atom in the formula (1),
Ri ₂ is a hydrogen atom, a chlorine atom, a sulfo group, a nitro group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms having a sulfo group, hydroxy Alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms having a carboxy group, an alkoxy group having 1 to 4 carbon atoms having a sulfo group, an alkoxy group having 1 to 4 carbon atoms having a hydroxy group Or an alkoxy group having 1 to 4 carbon atoms having a carboxy group.
Invention 5
The polarizing element according to any one of the inventions 1 to 4, wherein the azo compound represented by the formula (1) is an azo compound represented by the following formula (4):

In the formula, Ri ₃ is a hydrogen atom, a chlorine atom, a sulfo group, a nitro group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms having a sulfo group. Group, an alkyl group having 1 to 4 carbon atoms having a hydroxy group, an alkyl group having 1 to 4 carbon atoms having a carboxy group, an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and 1 to 4 carbon atoms having a hydroxy group Or an alkoxy group having 1 to 4 carbon atoms having a carboxy group,
m is the same as equation (2).
Invention 6
The polarizing element according to any one of the inventions 1 to 5, wherein the at least one dichroic dye is a compound represented by the formula (5) or the formula (6) or a salt thereof:

In the formula, each of Ab ₁ and Ab ₂ independently represents a substituted naphthyl group or a substituted phenyl group, and at least one of the substituents is a hydrogen atom, a sulfo group, or an alkyl group having 1 to 4 carbon atoms An alkoxy group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms having a sulfo group, a carboxy group, a nitro group, an amino group, or a substituted amino group,
Rb ₁ and Rb ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a sulfo group, or an alkoxy group having 1 to 4 carbon atoms having a sulfo group,

In the formula, Ag ₁ represents a substituted phenyl group or a substituted naphthyl group,
Bg and Cg are each independently represented by the following formula (7) or the following formula (8), and at least one represents the formula (7),
Xg ₁ may have an amino group which may have a substituent, a phenylamino group which may have a substituent, a phenylazo group which may have a substituent, or a substituent Exhibit a good benzoylamino group,

In the formula, Rg ₁ 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,
k is an integer of 0 to 2;

In the formula, Rg ₂ and Rg ₃ each 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 having a sulfo group.
Invention 7
The polarizer according to any one of Inventions 1 to 6, wherein the at least one dichroic dye is a compound represented by the following formula (9) or (10), a metal complex compound thereof, or a salt thereof :

In the formula, Ac ₁ represents a phenyl group or a naphthyl group having at least one substituent selected from the group consisting of a sulfo group and a carboxy group,
Rc ₁₁ to Rc ₁₄ each 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 having a sulfo group,

In the formula, Ac ₂ represents a phenyl group or a naphthyl group having at least one substituent selected from the group consisting of a sulfo group and a carboxy group,
Rc ₂₁ to Rc ₂₅ each 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 having a sulfo group,
Rc ₂₆ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms having a sulfo group,
Xc ₂ represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a sulfo group, an alkylamino group having 1 to 4 carbon atoms, a hydroxy group, an amino group, a substituted amino group, a carboxy group, and a carboxy An amino group which may have at least one substituent selected from the group consisting of ethylamino groups, a phenylamino group which may have a substituent, a phenylazo group which may have a substituent, a substituent A naphthotriazole group which may have one or more substituents, a benzoyl group which may have one or more substituents, or a benzoylamino group which may have one or more substituents,
p and q each independently represent an integer of 0 or 1.
Invention 8
Invention 1 to 7 wherein the at least one dichroic dye is an azo compound represented by the following formula (11), a metal complex compound thereof or a salt thereof, or an azo compound represented by the formula (12) or a salt thereof Polarizing element according to any one of:

In the formula, Ab ₁ represents a phenyl group or a naphthyl group having at least one substituent selected from the group consisting of a sulfo group and a carboxy group,
_Rb ₁₁ ~ Rb ₁₄ are each independently, represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms having an alkoxy group or a sulfo group having 1-4 carbon atoms, _{Rb 15} And R b ₁₆ each independently represent an alkoxy group having 1 to 4 carbon atoms,
Xb ₁ is composed of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a sulfo group, an amino group, an alkylamino group having 1 to 4 carbon atoms, a hydroxy group, a carboxy group and a carboxyethylamino group An amino group which may have at least one substituent selected from the group, a phenylamino group which may have a substituent, a phenylazo group which may have a substituent, and a substituent A naphthotriazole group, a benzoylamino group which may have a substituent, or a benzoyl group which may have a substituent,
d represents 0 or 1;

In the formula, Ab ₂ represents a phenyl group or a naphthyl group having at least one substituent selected from the group consisting of a sulfo group and a carboxy group,
Rb ₂₁ 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 ₂ has 1 to 4 carbon atoms At least one substituent selected from the group consisting of an alkyl group, an alkoxy group having 1 to 4 carbon atoms, an alkylamine group having 1 to 4 carbon atoms, a hydroxy group, a carboxy group, a sulfo group, an amino group and a substituted amino group Amino group which may have, phenylamino group which may have a substituent, phenylazo group which may have a substituent, naphthotriazole group which may have a substituent, even having a substituent Represents a good benzoylamino group or a benzoyl group which may have a substituent.
Invention 9
The polarizing element according to any one of Inventions 1 to 8, wherein the at least one dichroic dye is an azo compound represented by the following formula (13) or a salt thereof:

In the formula, Ay ₁ represents a hydrogen atom, 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,
Each of Ry ₁ and Ry ₂ independently represents a hydrogen atom, a sulfo group, 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. Represents
h is an integer of 1 to 3.
Invention 10
The polarizer according to any one of Inventions 1 to 9, wherein the at least one dichroic dye is iodine.
Invention 11
The polarizing element according to any one of Inventions 1 to 10, wherein the substrate is a polyvinyl alcohol resin film.
Invention 12
The polarizing element as described in any one of the inventions 1-11 whose degree of polarization is 99% or more.
Invention 13
In the transmissivity which is determined in a state in which the two polarizing elements are arranged so that their absorption axes are parallel to each other,
The difference between the average transmittance of each wavelength of 520 nm to 590 nm and the average transmittance of each wavelength of 420 nm to 480 nm is 5% or less as an absolute value, and the average transmittance of each wavelength of 600 nm to 640 nm, 520 nm to 590 nm The difference from the average value of the average transmittance of each wavelength of is 3% or less as an absolute value,
The polarizing element according to any one of the inventions 1 to 12.
Invention 14
According to JIS Z 8781-4: 2013, the absolute values of a * value and b * value determined at the time of natural light transmittance measurement are
Each of the polarizing elements alone is 1 or less (-1 ≦ a * −s ≦ 1 and −1 ≦ b * −s ≦ 1).
When two polarizing elements are arranged so that their absorption axes are parallel to each other, they are both 2 or less (-2 ≦ a * −p ≦ 2, −2 ≦ b * −p ≦ 2). ,
Invention 1. The polarizing element as described in any one of 1 to 13 (where a * -s represents a single a * value, b * -s represents a single b * value, a * -p represents a parallel position B * -p indicates b * at the parallel position).
Invention 15
In the transmissivity which is determined in a state in which the two polarizing elements are arranged so as to overlap each other so that their absorption axes are orthogonal to each other,
The difference between the average transmittance of each wavelength of 520 nm to 590 nm and the average transmittance of each wavelength of 420 nm to 480 nm is 3% or less as an absolute value, and the average transmittance of each wavelength of 600 nm to 640 nm, 520 nm to 590 nm The difference with the average transmittance of each wavelength of is 2% or less as an absolute value,
The polarizing element according to any one of the inventions 1-14.
Invention 16
A polarizing element according to any one of the inventions 1 to 15, and a polarizing plate comprising a transparent protective layer on at least one surface of the polarizing element.
Invention 17
An optical device comprising the polarizing element according to any one of the first to fifteenth aspects or the polarizing plate according to the sixteenth aspect.
Invention 18
The optical device according to claim 17, which is a liquid crystal display device.

The polarizing element of the present invention has high polarization characteristics in the visible range and absorbs light in the infrared range. In one aspect, it has high polarization performance over a wide band in the visible to infrared range. In one aspect, the polarizing element of the present invention is not only used for a polarizing plate and a liquid crystal display device, but is also a sensor or security device that functions with light in the visible range to the infrared range, and senses light in the visible range to the infrared range It can be used for cameras that can

In one aspect, the polarizing element of the present invention has high durability (moisture resistance, heat resistance, and / or light resistance), particularly high heat resistance, while having high transmittance and high contrast comparable to iodine-based polarizing plates. Have.

In one aspect, the polarizing element of the present invention has high durability while having infrared absorption.

In one aspect, the polarizing element of the present invention has an achromatic color in the visible range, has absorption in the infrared range, and has high durability.

In the present specification, a water-soluble compound that absorbs light in the infrared region or a salt thereof may be abbreviated as “infrared-absorbing water-soluble compound”.

In the claims and the specification of the present application, since the “substituent” may include a hydrogen atom, the hydrogen atom may be described as the “substituent” for the sake of convenience. The phrase "may have a substituent" means that the case where the substituent is not included is included. For example, the "optionally substituted phenyl group" includes an unsubstituted simple phenyl group and a substituted phenyl group. In addition, “lower” such as lower alkyl group and lower alkoxy group in the present application indicates that it has 1 to 4 carbon atoms, preferably 1 to 3 carbon atoms, unless otherwise specified.

Examples of the “lower (C1-C4) aliphatic hydrocarbon group” include linear alkyl groups such as methyl, ethyl, n-propyl and n-butyl, sec-butyl, tert- Examples thereof include branched chain alkyl groups such as butyl group and unsaturated hydrocarbon groups such as vinyl group.

Examples of the "lower (C1-C4) alkoxy group" include methoxy group, ethoxy group, propoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group and the like.

In this specification, it may be abbreviated and described as an "azo compound" including all of an "azo compound or its salt", or an "azo compound, its metal complex compound, or its salt."

[Polarizer]
The present application relates to a polarizing element including at least one dichroic dye exhibiting polarization characteristics in the visible range, and a water-soluble compound or a salt thereof that absorbs light in the infrared range.

As dichroic dyes exhibiting polarization characteristics in the visible region, compounds generally composed of iodine and iodine compounds such as potassium iodide and lithium iodide are known, and as other dichroic dyes, It is known that the dye described in Non-Patent Document 1 is used. Specifically, for example, Patent Document 21 and Patent Document 22 can be mentioned as an iodine-based polarizing plate, Patent Document 19 and Patent Document 20 can be mentioned as a dye-based polarizing plate, and a dye system capable of polarization control of only a specific wavelength If it is a polarizing plate, the patent document 23 and the patent document 24 will be mentioned, The dichroic dye which has a polarization function in such a visible region is mentioned. In particular, it is preferable to use an azo dye described in Formula (5) to Formula (14) described later, since an achromatic polarizing plate and a higher performance polarizing plate can be obtained.

(Water-soluble compounds that absorb light in the infrared range)

By using an infrared light-absorbing water-soluble compound having an ability to absorb light in the near infrared region, the polarizing element of the present invention can be provided with high durability. It is preferred to use a dye having maximum absorption in the near infrared region, in particular 700 to 1400 nm. More preferably, a dye having maximum absorption at 700 to 1100 nm, still more preferably 700 to 1000 m, particularly preferably 700 to 900 nm is used.

The types of infrared light-absorbing water-soluble compounds include phthalocyanines, naphthalocyanines, metal complexes, boron complexes, cyanines, squaryliums, dimoniums, diphenylamines and triphenylamines, quinones, and azos. Etc. Generally, these dyes lengthen the absorption wavelength by extending the existing π conjugated system, and the structure shows a wide variety of absorption wavelengths. Also, many of them are in the form of hydrophobic dyes and pigments, but they can be used as hydrophilic dyes by making them water soluble.

The phthalocyanine and naphthalocyanine type is a dye having a planar structure and a wide π conjugated surface. The central metal represented by M ₁ in the general formula (A-1) exhibits various absorptions, and generally, the central metal is Li, Na, K, Mg, Ti, Zr, V, Nb, Ta, Cr, Mo , W, Mn, Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, Ag, Zn, Cd, Hg, Al, Ga, In, Si, Ge, Sn, Pb, Sb Etc. VO, GeO, TiO etc. are mentioned as a metal oxide. Examples of the metal hydroxide include Si (OH) ₂ , Cr (OH) ₂ , Sn (OH) ₂ , AlOH and the like. Examples of the metal halide include SiCl ₂ , VCl, VCl ₂ , VOCl, FeCl, GaCl, ZrCl, AlCl and the like. Among these, metal atoms such as Fe, Co, Cu, Ni, Zn, Al and V, metal oxides such as VO, metal hydroxides such as AlOH, and the like are preferable, and metal oxides such as VO are more preferable. Although it is usually used as a pigment, it can also be dissolved in water by providing a water-soluble group as shown in the general formula 1 described in JP-A-2-217791.

The dye represented by the following general formula (A-1) is preferably, for example, a dye represented by the following compound example (A-1-1). The broken aromatic ring in the general formula (A-1) means that it may or may not be present. E and f in the compound example (A-1-1) each independently represent an integer of 0 to 12, and indicate that the sum of e and f is 0 to 12, and in particular, e is 1 to 4 and f is 0 Is preferred.

The quinone type is a dye having a wide absorption, and is a dye represented by the following general formula (A-2). In the formula, Ar ₁ and Ar ₂ are desirably a cyclic structure composed of an aromatic ring or a heterocyclic ring, and a heterocyclic ring is more preferable for increasing the absorption wavelength. For example, anthraquinone dyes as described in JP-A-61-221264 can be mentioned. In addition, these rings may have a substituent, for example, an amino group which may have a substituent, a nitro group, a sulfo group, an alkyl group, an alkoxy group, an alkyl group having a sulfo group, an alkyl group having a hydroxyl group And the like. It is preferable that X is an oxygen atom or a nitrogen atom. When X is a nitrogen atom, the nitrogen atom represents a hydrogen adduct NH, or a nitrogen atom substituted with an alkyl group having 1 to 4 carbon atoms, a phenyl group which may have a substituent, or the like. .
Although quinones are hydrophobic in many structures, those which can be dissolved in water by providing a water-soluble group have also been reported. For example, indanthrone dyes as described in JP-A-2006-508034 can be mentioned.
The above-mentioned amino group which may have a substituent represents a substituted or unsubstituted amino group, and as the substituted amino group, a monomethylamino group, a monoethylamino group, a monobutylamino group, a monophenylamino group, etc. Di-substituted amino groups such as mono-substituted amino group, dimethylamino group, diethylamino group, dibutylamino group, diphenylamino group, methylphenylamino group and the like can be mentioned. Examples of the alkyl group include linear alkyl groups such as methyl group, ethyl group, propyl group, n-butyl group and n-octyl group, branched chain alkyl groups such as isopropyl group, secondary butyl group and tertiary butyl group, and cyclopentyl group And cyclic alkyl groups such as cyclohexyl group. As an alkoxy group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group etc. are mentioned. Examples of the alkyl group having a sulfo group include sulfomethyl group, sulfoethyl group, sulfopropyl group, sulfobutyl group and the like. Examples of the alkyl group having a hydroxyl group include a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group and a hydroxybutyl group.

The dye represented by the following general formula (A-2) is preferably a dye represented, for example, by the following compound example (A-2-1). In the compound example (A-2-1), n represents an integer of 1 to 12, and when n is 1 or more, each sulfo group may be in a free form or in the form of a salt, or is free Both the form and the salt form may be contained in any proportion.

The cyanine dye is a dye having strong absorption in the near infrared region, and is represented by formula (A-3) or (A-4), and Ar ₃ to Ar ₆ each represent a heterocycle. Examples of the heterocyclic ring include a thiazole ring, a benzothiazole ring, a naphthothiazole ring, a thiazoline ring, an oxazole ring, a benzoxazole ring, a naphthoxazole ring, an oxazoline ring, a selenazole ring, a benzoselenazole ring, a naphtho serenazole ring, a quinoline ring and the like. And preferably a benzothiazole ring or a naphthothiazole ring. Each heterocycle may have any substituent, and preferably has an aqueous solution group. Examples of the water-soluble group include a sulfo group, a hydroxyl group, an alkyl group having a sulfo group, and an alkyl group having a hydroxyl group. These substituents may be substituted on the ring of Ar ₃ to Ar ₆ or may be bonded on the nitrogen atom in the heterocyclic ring. The number c of methine chains in the general formula (A-3) is represented by an integer of 1 to 7, and 3 to 5 is particularly preferable. The methine chain may have a substituent R ₄ , and examples thereof include a phenyl group which may have a substituent. Also, if c is R ₄ there are a plurality of two or more, each of R ₄ may match the same or may be different. Ar _{7 in} General Formula (A-4) represents a cyclic skeleton having 5 to 7 carbon atoms, and the substituent W is a halogen, a phenylamino group which may have a substituent, or phenoxy which may have a substituent Groups, and optionally substituted phenylthio groups and the like. The substituent in this case may have a water-soluble group. Further, this dye is an inner salt type or an intermolecular salt type, and in the case of an intermolecular salt type, a halide salt, a perchlorate, an antimony fluoride salt, a phosphorus fluoride salt, a boron fluoride salt, a trifluoromethane salt And organic salts such as naphthalenesulfonic acid, and the like. Specific examples thereof include indocyanine green and water-soluble dyes described in JP-A-63-33477, and examples thereof include the following compound examples (A-3-1) and (A-4-1) to (A-). 4-3). The alkyl group having a sulfo group and the alkyl group having a hydroxyl group may be the same as described above. Examples of the halogen include fluorine, chlorine, bromine, iodine and the like, and chlorine is preferable.

The squarylium system having a similar structure to the cyanine system is a dye having a square acid as a central skeleton as represented by the following general formula (A-5). It is desirable that Ar ₈ and Ar ₉ in the general formula (A-5) have the same heterocyclic ring as the cyanine type. In addition, this dye also takes an inner salt type and an intermolecular type, and takes the form of a salt similar to cyanine type. Although many of these dyes exhibit hydrophobicity, they can be dissolved in water by providing a water-soluble group as in the cyanine dye.

Azo dyes are dyes that absorb in the visible light range, and water-soluble inks are the main application, but dyes that can absorb in the near infrared range are commercially available by broadening the absorption. For example, for the purpose of producing a black ink generally described in WO 2013/035560, C.I. I. Acid Black 2 (manufactured by Orient Chemical Industries, Ltd.), C.I. I. Examples include the use of Direct Black 19 (manufactured by Aldrich Kogyo Co., Ltd.). These azo dyes can also be complexed with metals. In this case, it is represented as the following general formula (A-6), cobalt, nickel, etc. are mentioned as central metal M ₂ , and Ar ₁₁ and B ₁ are exemplified by aromatic rings such as benzene ring or naphthalene ring. Particularly, the dye structure described in JP-A-59-11385 is preferable.

The metal complex system is represented by the following general formula (A-7) or the following general formula (A-8). In the formula, M ₃ and M ₄ represent metals, and Pd, Ni, Co, and Cu are generally used, but Ni is particularly preferable. R ₇₁ , R ₇₂ , R ₈₁ and R ₈₂ each represents an arbitrary substituent, and specifically, a halogen atom, an alkyl group which may have a sulfo group, an alkoxy group which may have a sulfo group, cyano Groups, amino groups, nitro groups, optionally substituted phenyl groups and the like. Each of X ₁ to X ₄ independently represents a nitrogen atom, an oxygen atom, or a sulfur atom. When X ₁ to X ₄ are nitrogen atoms, the nitrogen atoms are substituted with NH which is a hydrogen adduct, or an alkyl group having 1 to 4 carbon atoms, a phenyl group which may have a substituent, or the like. It may be a nitrogen atom.

The boron complex system is represented by the following general formula (A-9), and the dye structure described in JP-A-2010-106248 is preferable.

In the above general formula (A-9), R ₉₃ and R ₉₄ each is preferably a hydrogen atom, an alkyl group or a phenyl group, R ₉₅ is preferably a strong electron attractive group such as a nitro group or a cyano group, and Ar ₉₀ is a substituent a phenyl group is preferable have a, Ar ₁₂ is preferably an annular structure composed of an aromatic ring or a heterocyclic ring, the heterocyclic ring is more preferred for long absorption wavelength. Y is preferably a sulfur atom or an oxygen atom.

The diimmonium type is a dye having absorption on the relatively long wavelength side (950 to 1100 nm) even in the near infrared region, and is represented by the following general formula (A-10).

In the above general formula (A-10), R ₆ to R ₁₃ include an alkyl group which may have a substituent, an aromatic ring which may have a substituent, and the like. Although generally a hydrophobic dye, a dye disclosed in JP 2001-181184 A, to which a water-soluble group is added, is also disclosed. This dye is also an intramolecular salt, intermolecular salt type, and in the case of intermolecular salt type, Q- is a halide ion, perchlorate ion, antimony fluoride ion, phosphorus fluoride ion, boron fluoride ion, trifluoromethane Sulfonic acid ion, bis (trifluoromethane) sulfonic acid imide ion, naphthalene sulfonic acid ion and the like can be mentioned. As the alkyl group which may have a substituent, for example, halogen, hydroxyl group, cyano group, substituted or unsubstituted amino group, carboxy group, sulfo group, phosphoric acid group, carboxyalkyl group, alkoxy group, phenoxy group, etc. And a linear or branched or cyclic C1-C8 alkyl group substituted by The halogen may be the same as described above. As a substituted or unsubstituted amino group, an amino group, a methylamino group, a dimethylamino group, a dibutylamino group, a phenylamino group, a diphenylamino group etc. are mentioned, for example. As a carboxyalkyl group, a methyl carboxy group, an ethyl carboxy group etc. are mentioned, for example. As an alkoxy group, a methoxy group, an ethoxy group, butoxy group, tertiary butoxy group etc. are mentioned, for example.

The diphenylamine triphenylamines are represented by the following general formula (A-11) or the following general formula (A-12).

R ₁₄ to R _{17 in} the general formula (A-11) and R ₁₈ to R ₂₃ in the general formula (A-12) are each independently a hydrogen atom or an alkyl group containing at least one carbon atom, The alkyl group optionally includes one or more hetero atoms selected from nitrogen atom, oxygen atom, sulfur atom and halogen atom, and one or more nitrogen atoms are cation radicals, The cation radicals are equilibrated in charge by one or more anions.

The infrared light-absorbing water-soluble compound is preferably an azo compound or a salt thereof.

As the above-mentioned azo compound, an azo compound represented by the above-mentioned formula (1) is preferable.

By including the azo compound represented by the above formula (1) or a salt thereof in the polarizing element of the present invention, it is possible to significantly improve the durability. Furthermore, it is possible to obtain a polarizing element capable of providing high polarization over a wide wavelength in the infrared region. With regard to a general dye-based polarizing element, for example, although a polarizing element exhibiting a high degree of polarization in the visible region can be obtained in Patent Documents 19 and 20, it is impossible to provide a polarizing element having polarization in the infrared region. In addition, the change in light transmittance in a wavelength region longer than 680 nm is extremely large in the durability test, and the polarizing plate has a problem that the color changes, for example, changes to red after the durability test. With respect to the problem, it is extremely preferable to use an azo compound represented by the formula (1), since a polarizing element having higher durability and a polarization function in a wide band can be obtained.

In the above formula (1), Ai ₁ and Ai ₂ are each independently represented by a hydrogen atom, an azo group, or the above formula (2) (with the exception of those in which both Ai ₁ and Ai ₂ are hydrogen atoms), It is preferable that Ai ₁ and Ai ₂ be each represented by Formula (2). Further, -NH- is a combination of a and a ', b and b', a and b 'and b and a', and is preferably a combination of a and a '.

In the above formula (2), the rings substituted by Ri ₁ are each independently a benzene ring when there is no ring represented by the broken line, and a naphthalene ring when there is a ring represented by the broken line It is. Ri ₁ each independently represents a chlorine atom, a sulfo group, a nitro group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms having a sulfo group, An alkyl group having 1 to 4 carbon atoms having a hydroxy group, an alkyl group having 1 to 4 carbon atoms having a carboxy group, an alkoxy group having 1 to 4 carbon atoms having a sulfo group, an alkoxy having 1 to 4 carbon atoms having a hydroxy group And a substituent selected from the group consisting of a C 1 to C 4 alkoxy group having a carboxy group.

Examples of the alkyl group having 1 to 4 carbon atoms include linear alkyl groups such as methyl, ethyl, propyl and normal butyl, and chain alkyl groups such as secondary butyl and tertiary butyl. Examples of the alkoxy group having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, a propoxy group and a butoxy group. Examples of the alkyl group having 1 to 4 carbon atoms having a sulfo group include sulfomethyl group, sulfoethyl group, sulfopropyl group, sulfobutyl group and the like. Examples of the alkyl group having 1 to 4 carbon atoms having a hydroxy group include a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group and a hydroxybutyl group.

The alkoxy group having 1 to 4 carbon atoms having a hydroxy group is preferably a linear alkoxy group in which the alkoxy group end is substituted with a hydroxy group, more preferably a 4-hydroxypropoxy group or a 4-hydroxybutoxy group is there. As a C1-C4 alkoxy group which has a carboxy group, Preferably it is a linear alkoxy group by which the alkoxy group terminal was substituted by the carboxy group, More preferably, it is 4-carboxy propoxy group or 4-carboxy butoxy group . As a C1-C4 alkoxy group which has a sulfo group, Preferably it is a linear alkoxy group by which the alkoxy group terminal was substituted by the sulfo group, More preferably, it is 4-sulfo propoxy group or 4-sulfo butoxy group .

In the above formula (2), Bi each independently represents a phenyl group which may have a substituent or a naphthyl group which may have a substituent.

As a substituent which the said phenyl group and a naphthyl group may have, a chlorine atom, a sulfo group, a nitro group, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a sulfo group An alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms having a hydroxy group, an alkyl group having 1 to 4 carbon atoms having a carboxy group, an alkoxy group having 1 to 4 carbon atoms having a sulfo group, It represents a substituent selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms having a hydroxy group and an alkoxy group having 1 to 4 carbon atoms having a carboxy group.

When Bi in the above formula (2) has a hydroxy group as a substituent, an —O—Cu—O— bond is formed by the hydroxy group in the formula (1) and a copper atom to form an azo metal complex compound or its compound It is possible to use salt.

In the above formula (2), m represents an integer of 1 to 3, preferably 1 or 2, and more preferably 2.

When Bi has a substituent but is more phenyl, the substitution position is not particularly limited, but a combination of 2 and 4 positions, 2 and 5 positions, or 3 and 5 positions is preferable, and 2 and 4 Position is particularly preferred. In the case where Bi is a naphthyl group which may have a substituent, the substitution position is not particularly limited, but a combination of 2 position, 6 position, 7 position, 2 position and 6 position, 2 position and 7 position is preferable, 2 position , 2 and 7 are particularly preferred. In Formula (1), Ai ₁ and Ai ₂ are each independently represented by a hydrogen atom or Formula (2), but are excluded when both Ai ₁ and Ai ₂ are hydrogen atoms, and a hydrogen atom and Formula (2) the combination of), or _Ai 1, Ai is preferably a combination of ₂ together form a moiety of formula _(2), Ai 1, the combination of Ai ₂ together form a moiety of formula (2) is particularly preferred.

When said Formula (2) is represented by said Formula (3), since durability of the polarizing element of this application can further be improved and the polarization | polarized-light performance in an infrared region can be improved, it is preferable. In the formula (3), Ri ₁ is the same as Ri ₁ in the formula (2).

In the above formula (3), Ri ₂ represents a hydrogen atom, a chlorine atom, a sulfo group, a nitro group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or 1 carbon atom having a sulfo group An alkyl group of to 4, an alkyl group having 1 to 4 carbon atoms having a hydroxy group, an alkyl group having 1 to 4 carbon atoms having a carboxy group, an alkoxy group having 1 to 4 carbon atoms having a sulfo group, a carbon having a hydroxy group It represents a substituent selected from the group consisting of alkoxy groups of 1 to 4 and alkoxy groups of 1 to 4 carbon atoms having a carboxy group. The substitution position of Ri ₂ in the formula (3) may take ortho, meta or para position with respect to the position at which the oxygen atom is substituted, but is preferably substituted at the para position. Further, it is preferable to form —O—Cu—O— by the oxygen atom in the formula (3), the —OH in the formula (1) and the copper atom. The azo compound represented by the above-mentioned formula (1) is more preferable because it is possible to provide a polarizing element for an infrared region having higher performance and a wide band by being the above-mentioned formula (4). In the formula (4), m is the same as the above formula (2), Ri ₃ may be the same as Ri ₂ in the formula (3), and the substitution position of Ri ₃ may be the same as Ri ₂ .

The azo compounds represented by formulas (1) to (4) may be in free form or in the form of a salt. The salts may be, for example, alkali metal salts such as lithium salts, sodium salts and potassium salts, alkaline earth metal salts such as calcium salts, organic salts such as ammonium salts and alkylamine salts, preferably sodium salts. It is.

Although the specific example of an azo compound represented by said Formula (1) is given to the following, it is not specifically limited to these. The sulfo, carboxy and hydroxy groups in the formula are represented as free acids.

The azo compound represented by the above formula (1) or a salt thereof can be diazotized and coupled according to a conventional method for producing an azo dye as described, for example, in Patent Document 14, Patent Document 15 and Non-patent Document 2. Can be manufactured by performing.

The following method is mentioned as an example of a specific manufacturing method. For example, aminothiazoles represented by the following formula (A) are diazotized, primary coupling is performed with anilines represented by the following formula (B) or aminonaphthalenes represented by the following formula (C), and the following formula (D) Or the monoazo amino compound shown by following formula (E) is obtained.
The disazo amino compound (D) or (E) is diazotized as Ai ₁ component or Ai ₂ component, respectively, and azo compound of formula (1) is obtained by secondary coupling with naphthols of the following formula (F) Is obtained.

In the above formulas (A) to (F), the presence or absence of the broken line in the ring substituted by Ri ₁ and Ri ₁ has the same meaning as that in formula (2), and Ri ₂ is the same as that in formula (3) R ₂₄ or R ₂₅ each independently represents a hydrogen atom, a chlorine atom, a sulfo group, a nitro group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a sulfo group An alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms having a hydroxy group, an alkyl group having 1 to 4 carbon atoms having a carboxy group, an alkoxy group having 1 to 4 carbon atoms having a sulfo group, The alkoxy group having 1 to 4 carbon atoms having a hydroxy group and the alkoxy group having 1 to 4 carbon atoms having a carboxy group are shown, and m has the same meaning as that in the formula (2).
Alkyl group having 1 to 4 carbon atoms, alkoxy group having 1 to 4 carbon atoms, alkyl group having 1 to 4 carbon atoms having a sulfo group, alkyl group having 1 to 4 carbon atoms having a hydroxy group, carbon number having a carboxy group The alkyl group having 1 to 4 carbon atoms, the alkoxy group having 1 to 4 carbon atoms having a sulfo group, the alkoxy group having 1 to 4 carbon atoms having a hydroxy group, and the alkoxy group having 1 to 4 carbon atoms having a carboxy group are each as described above. It may be similar to

In the above production method, the diazotization step is carried out by a so-called "sequential method" in which a nitrite such as sodium nitrite is mixed with an aqueous solution or suspension of a mineral acid such as hydrochloric acid or sulfuric acid as a diazo component, or It is preferable to carry out the so-called "inverse method" in which nitrite is added to a neutral or weakly alkaline aqueous solution and this is mixed with a mineral acid. The temperature for diazotization is preferably -10 to 40.degree. The coupling step with anilines is preferably carried out by mixing an acidic aqueous solution such as hydrochloric acid or acetic acid with each of the above diazo liquids, at a temperature of -10 to 40 ° C and under acidic conditions of pH 2 to 7.

The monoazo compound of the formula (D) or the formula (E) obtained by the coupling reaction may be filtered as it is, or it may be precipitated by acid precipitation or salting out and removed by filtration, or the solution or suspension may be used as it is You can go to When the diazonium salt is poorly soluble and is in the form of a suspension, it can be filtered and used as a press cake in the next coupling step.

The tertiary coupling reaction of the diazotized compound of the monoazo compound of the formula (D) or the formula (E) with the naphthols represented by the formula (F) has a temperature of −10 to 40 ° C. and a neutral pH of 7 to 10. It is preferred to be carried out under alkaline conditions. After completion of the reaction, the obtained azo compound or salt of the formula (1) is preferably precipitated by salting out and filtered out. In addition, if 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 compound represented by the above formula (A) is a 2-aminobenzothiazole in the absence of the ring represented by the broken line, for example, 2-amino-6-sulfobenzothiazole, 2-amino-7 And -methoxy-6-sulfobenzothiazole, 2-amino-4,6-disulfobenzothiazole, 2-amino-7-methoxy-4,6-disulfobenzothiazole, and the like. When a ring represented by a broken line is present, it is 2-aminonaphthothiazoles, for example, 2-amino-6,8-disulfonaphthothiazole, 2-amino-4,6,8-trisulfonaphthothiazole , 2-amino-4-chloro-6,8-disulfonaphthothiazole, 2-amino-6-sulfopropoxy-4,8-disulfonaphthothiazole, 2-amino-6-sulfopropoxy-4,7,8 -Trisulfonaphthothiazole, 2-amino-6-methoxy-4,7,8-trisulfonaphthothiazole, 2-amino-7-sulfopropoxy-4,9-disulfonaphthothiazole, 2-amino-4-sulfo Propoxy-5,7,9-trisulfonaphthothiazole, etc., and 2-amino-6-sulfobenzothiazole, 2-amino-7-methoxy-6- Sulfobenzothiazole and 2-amino-6,8-disulfonaphthothiazole are preferred.

As anilines of the formula (B), 3- (2-amino-4-methylphenoxy) propane-1-sulfonic acid, 3- (2-aminophenoxy) as anilines having a lower alkoxy group having a sulfo group Propane-1-sulfonic acid, 3- (2-amino-4-methylphenoxy) butane-1-sulfonic acid and the like can be mentioned. Examples of other anilines include aniline, 2-methyl aniline, 3-methyl aniline, 2-ethyl aniline, 3-ethyl aniline, 2,5-dimethyl aniline, 2,5-diethyl aniline, 2-methoxy aniline, Examples thereof include 3-methoxyaniline, 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. Examples of aminonaphthalenes of the formula (C) include 1-aminonaphthalene, 1-aminonaphthalene-6-sulfonic acid, 1-aminonaphthalene-7-sulfonic acid, 1-amino-2-methoxynaphthalene-6-sulfone Acid, 1-amino-2-methoxynaphthalene-7-sulfonic acid, 1-amino-2-ethoxynaphthalene-6-sulfonic acid, and 1-amino-2-ethoxynaphthalene-7-sulfonic acid, preferably Examples include 1-aminonaphthalene-7-sulfonic acid and 1-amino-2-methoxynaphthalene-7-sulfonic acid. These aminonaphthalenes may be protected at the amino group. Examples of the protective group include the ω-methanesulfone group.

The azo compound represented by the above formula (1) or a salt thereof provides a high-performance polarizing plate having high polarization performance in the infrared region, as well as moisture resistance, heat resistance, and / or light resistance. Therefore, the polarizing element according to the present invention is suitable for producing an automotive polarizing plate used under high temperature and high humidity conditions, a neutral gray polarizing plate for outdoor display, and various sensors which require control by light in the infrared region. .

For the polarizing element, at least one kind of dichroic dye exhibiting polarization characteristics in the visible region is used for the purpose of color correction and / or improvement of polarization performance to the extent that the performance of the present invention is not impaired. For example, at least one dichroic dye that exhibits polarization characteristics in the visible region other than the azo compound represented by Formula (1) may be contained.

In order to produce an achromatic polarizing element, the polarizing element of the present invention preferably contains the azo compound of the formula (5) or the formula (6) or a salt thereof, or one or both of them. The formulation has high transmittance and can provide an achromatic polarizing element with a high degree of polarization. The polarizing element containing the azo compound of Formula (5) or Formula (6) leads to being able to provide a highly durable and reliable liquid crystal display.

First, equation (5) will be described. In the formula (5), Ab ₁ and Ab ₂ each independently represent a substituted naphthyl group or a substituted phenyl group, and at least one of the substituents is a hydrogen atom, a sulfo group, a lower alkyl group, or a lower group An alkoxy group, a lower alkoxy group having a sulfo group, a carboxy group, a nitro group, an amino group, or a substituted amino group, and Rb ₁ and Rb ₂ each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group Or a lower alkoxy group having a sulfo group.

Furthermore, in order to obtain a polarization element having higher transmittance, high polarization degree, and more achromatic hue in parallel and orthogonal positions, Rb ₁ and Rb _{2 in} the equation (5) are The substituents are preferably each independently a methyl group or a methoxy group, and more preferably a methoxy group.

Furthermore, in order to obtain a polarization element having higher transmittance, high polarization degree, and more neutral hues of parallel and orthogonal positions, Ab ₁ and Ab ₂ of the formula (5) are Each of them is preferably a naphthyl group having a sulfo group or a carbonyl group, and more preferably a naphthyl group having a sulfo group because a high contrast polarizing plate can be obtained.

Specific examples of the azo compound represented by the formula (5) used in the present application are shown below in the form of free acid.

Next, the compound of formula (6) will be described.

In formula (6), Ag ₁ represents a phenyl group having a substituent or a naphthyl group having a substituent. When Ag ₁ is a phenyl group, it is preferable to have at least one sulfo group or carboxy group as a substituent. When the phenyl group has two or more substituents, at least one of the substituents is a sulfo group or a carboxy group, and the other substituents are a sulfo group, a carboxy group, a lower alkyl group, a lower alkoxy group, a sulfo group It is preferable that it is a lower alkoxy group having the following, a nitro group, an amino group, an acetylamino group, or a lower alkylamino group-substituted amino group. The other substituent is more preferably a sulfo group, a methyl group, an ethyl group, a methoxy group, an ethoxy group, a carboxy group, a nitro group or an amino group, and particularly preferably a sulfo group, a methyl group, a methoxy group or an ethoxy group. A group or a carboxy group. As the lower alkoxy group having a sulfo group, linear alkoxy is preferable, and the substitution position of the sulfo group is preferably an alkoxy group end, more preferably a 3-sulfopropoxy group and a 4-sulfobutoxy group, particularly preferably 3- It is a sulfopropoxy group. The number of substituents which the phenyl group has is preferably 1 or 2, and the substitution position is not particularly limited, but only the 4-position, the combination of 2-position and 4-position, and the combination of 3-position and 5-position are preferred.

When Ag ₁ is a substituted naphthyl group, it is preferable to have at least one sulfo group as the substituent. When a naphthyl group has two or more substituents, preferably, at least one of the substituents is a sulfo group, and as the other substituent, a sulfo group, a hydroxy group, a carboxy group, or a lower group having a sulfo group It is an alkoxy group. It is particularly preferable that the naphthyl group has two or more sulfo groups as a substituent. As the lower alkoxy group having a sulfo group, linear alkoxy is preferable, and the substitution position of the sulfo group is preferably an alkoxy group terminal. More preferably, they are 3-sulfopropoxy group and 4-sulfobutoxy group, and particularly preferably 3-sulfopropoxy group. When the number of sulfo groups which a naphthyl group has is 2, the combination position of a sulfo group is preferably a combination of 4 and 8 positions, and a combination of 6 and 8 positions is preferable, and a combination of 6 and 8 positions is more preferable. When the number of sulfo groups that a naphthyl group has is 3, the substitution position of the sulfo group is preferably a combination of 1, 3, and 6 positions.

Although Bg and Cg in the said Formula (6) are respectively independently represented by following formula (7) or following formula (8), at least one of Bg and Cg is represented by Formula (7).

In the above formulas (7) and (8), Rg ₁ to Rg ₃ each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, or a lower alkoxy group having a sulfo group. In the formula (7), Rg ₁ is preferably a hydrogen atom, a lower alkyl group or a lower alkoxy group, more preferably a hydrogen atom, a methyl group or a methoxy group, and particularly preferably a hydrogen atom or a methoxy group It is. As the lower alkoxy group having a sulfo group, linear alkoxy is preferable, and the substitution position of the sulfo group is preferably an alkoxy group terminal. More preferably, they are 3-sulfopropoxy group and 4-sulfobutoxy group, and particularly preferably 3-sulfopropoxy group. The substitution position of Rg ₁ is preferably 2-position or 3-position, when the azo group on the Ag ₁ side is 1-position. More preferably, when the azo group on the Ag ₁ side is _1- position, it is more preferably 3-position. When there is a sulfo group, the substitution position of the sulfo group is preferably 6- or 7-position, more preferably 6-position. k represents an integer of 0 to 2; In Formula (8), Rg ₂ and Rg ₃ each independently are preferably a hydrogen atom, a lower alkyl group, a lower alkoxy group, or a lower alkoxy group having a sulfo group, and more preferably a hydrogen atom, a methyl group , Methoxy group, 3-sulfopropoxy group or 4-sulfopropoxy group. As the substitution position of Rg ₂ or Rg ₃ , when the azo group on the Xg ₁ side is 1 position, only 2 position, 5 position only, 2 and 5 positions, 3 and 5 positions, 2 position and 6 position Or a combination of 3 and 6 positions is applicable, preferably only 2 positions, only 5 positions, 2 positions and 5 positions.

Xg ₁ in the above formula (6) 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, or a substituent Or benzoylamino group. Xg ₁ is preferably an amino group which may have a substituent or a phenylamino group which may have a substituent, more preferably a phenylamino group. The amino group which may have a substituent is preferably an amino having one or two selected from the group consisting of a hydrogen atom, a methyl group, a methoxy group, a sulfo group, an amino group, and a lower alkylamino group. And more preferably a hydrogen atom, a methyl group, or an amino group having one or two sulfo groups. The phenylamino group which may have a substituent is preferably one or two selected from the group consisting of a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group, an amino group and a lower alkylamino group. It is a phenylamino group having a substituent, more preferably a phenylamino group 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. . Although the substitution position is not particularly limited, it is preferable that one of the substituents is p-position to the amino group of the phenylamino group. The phenylazo group is preferably selected from the group consisting of a hydrogen atom, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an amino group, a hydroxy group and a carboxyethylamino group. It is a phenylazo group having three. The benzoylamino group which may have a substituent is preferably a benzoylamino group having one substituent selected from the group consisting of a hydrogen atom, a hydroxy group, an amino group, and a carboxyethylamino group. The substitution position of Xg ₁ is preferably 6- or 7-position, more preferably 6-position, when the hydroxy group of the substituted naphthyl group is 1-position.

The azo compound represented by the formula (6) or a salt thereof is preferably an azo compound represented by the following formula (6 ′) or a salt thereof because the performance is particularly improved.

In the above formula (6 ′), Ag ₁ represents a phenyl group having a substituent or a naphthyl group having a substituent, and Rg ₄ and Rg ₅ each independently represent the same as Rg ₁ in the formula (7), Xg ₁ has the same meaning as Xg ₁ in the formula (6). Each of k ₁ and k ₂ independently represents an integer of 0 to 2.

As a specific example of the azo compound represented by Formula (6), for example,
C. I. Direct Blue 34,
C. I. Direct Blue 69,
C. I. Direct Blue 70,
C. I. Direct Blue 71,
C. I. Direct Blue 72,
C. I. Direct Blue 75,
C. I. Direct Blue 78,
C. I. Direct Blue 81,
C. I. Direct Blue 82,
C. I. Direct Blue 83,
C. I. Direct Blue 186,
C. I. Direct Blue 258,
Benzo Fast Chrome Blue FG (C.I. 34225),
Benzo Fast Blue BN (C.I. 34120),
C. I. Direct Green 51,
And azo compounds such as

Below, the specific example of an azo compound represented by Formula (6) is shown in the form of a free acid.

In the polarizing element of the present invention, the content of the azo compound represented by the formula (5) or the formula (6) or a salt thereof is preferably 0.0001 to 5 parts by mass with respect to 100 parts by mass of the aqueous solution. And more preferably 0.001 to 1 part by mass.

The method for obtaining the azo compound represented by the formula (5) and the azo compound can be obtained, for example, by the method described in WO 2012/165223, but is not limited thereto.

The azo compound represented by the formula (6) or a salt thereof is disclosed, for example, in JP-A-1-161202, JP-A-01-172907, JP-A-01-248105, JP-A-01-265205, and the like. Although it can synthesize | combine by the method described in the 07-92531 gazette etc., it is not limited to these.

In one aspect, the polarizing element of the present invention comprises the azo compound represented by the above formula (9) or (10), a metal complex compound thereof, or a salt thereof. In order to produce the polarizing element, it is preferable to use an infrared light absorbing compound and an azo compound of the formula (9) or the formula (10) independently or simultaneously, with high transmittance, It is possible to provide an achromatic polarization element with a high degree of polarization. In particular, a polarizing element using the azo compound of the formula (9) or the formula (10) can provide a highly durable and highly reliable liquid crystal display.

First, equation (9) will be described below.

In the above formula (9), Ac ₁ represents a phenyl group or a naphthyl group having at least one substituent selected from the group consisting of a sulfo group and a carboxy group, and Rc ₁₁ to Rc ₁₄ each independently represent Represents a lower alkoxy group having a hydrogen atom, a lower alkyl group, a lower alkoxy group or a sulfo group

In the above formula (9), when Ac ₁ is a phenyl group, it is preferable to have at least one sulfo group or carboxy group as a substituent. When the phenyl group has two or more substituents, at least one of the substituents is a sulfo group or a carboxy group, and the other substituent is preferably a sulfo group, a carboxy group, a lower alkyl group or a lower alkoxy. Group, a lower alkoxy group having a sulfo group, a nitro group, an amino group, an acetylamino group and a lower alkylamino group-substituted amino group, more preferably a sulfo group, a methyl group, an ethyl group or a methoxy group, It is selected from the group consisting of an ethoxy group, a carboxy group, a nitro group and an amino group, and particularly preferably selected from a group consisting of a sulfo group, a methyl group, a methoxy group, an ethoxy group and a carboxy group. The lower alkoxy group having a sulfo group is preferably a linear alkoxy group, and the substitution position of the sulfo group is preferably at the end of the alkoxy group. The lower alkoxy group having such a sulfo group is more preferably a 3-sulfopropoxy group or a 4-sulfobutoxy group, and particularly preferably a 3-sulfopropoxy group. When the phenyl group has a sulfo group as a substituent, the number of sulfo groups is preferably one or two. The substitution position of the sulfo group is not particularly limited, but in the case where there is one sulfo group, the 4-position of the phenyl group is preferable with the position of the azo group being 1 position, and two sulfo groups are present. When it is the combination of 2- and 4-position of phenyl group or the combination of 3- and 5-position of phenyl group is preferable.

In the above formula (9), when Ac ₁ is a naphthyl group, it is preferable to have at least one sulfo group as a substituent. When the naphthyl group has two or more substituents, at least one of the substituents is a sulfo group, and the other substituent is preferably a sulfo group, a hydroxy group, a carboxy group and a lower alkoxy having a sulfo group. It is selected from the group consisting of The lower alkoxy group having a sulfo group is preferably a linear alkoxy group, and the substitution position of the sulfo group is preferably at the end of the alkoxy group. The lower alkoxy group having such a sulfo group is more preferably a 3-sulfopropoxy group or a 4-sulfobutoxy group, and particularly preferably a 3-sulfopropoxy group. When the number of sulfo groups substituted by a naphthyl group is two, the position of the azo group is 2-position, and the substitution position of the sulfo group is 4-, 8-position combination or 6-, 8- position of a naphthyl group. A combination of 6- and 8-positions is more preferred. When the number of sulfo groups substituted by a naphthyl group is three, the substitution position of the sulfo group is preferably a combination of 1-, 3- and 6-positions.

In the above formula (9), each of Rc ₁₁ to Rc ₁₄ independently represents a hydrogen atom, a lower alkyl group, a lower alkoxy group or a lower alkoxy group having a sulfo group. The lower alkoxy group having a sulfo group is preferably a linear alkoxy group, and the substitution position of the sulfo group is preferably at the end of the alkoxy group. Rc ₁₁ to Rc ₁₄ are preferably each independently a hydrogen atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group, a 3-sulfopropoxy group or a 4-sulfobutoxy group, and particularly preferably a hydrogen atom, It is a methyl group, a methoxy group or a 3-sulfopropoxy group. As the substitution position of the phenyl group by which Rc ₁₁ to Rc ₁₄ is substituted, when the substitution position of the azo group on the ureido skeleton side is 1 position, preferably only the 2-position of the phenyl group, only the 5-position, 2- A combination of 1-position and 6-position, a combination of 2-position and 5-position, a combination of 3-position and 5-position, particularly preferably only 2-position, 5-only, 2-position and 5-position It is a combination of orders. Note that the 2-position only, only the 5-position, in relation to the _{Rc 11} and _Rc 12, _{Rc 13} and _{Rc 14,} one of _{Rc 11} and _{Rc 12} or _{Rc 13} and _{Rc 14} is 2- It means that it has one substituent other than a hydrogen atom at only the position or 5-position, and the other is a hydrogen atom.

Among the azo compounds represented by the above formula (9), an azo compound represented by the following formula (9b) is particularly preferable:

In the formula, Ac ₁ and Rc ₁₁ to Rc ₁₄ are as defined in the above formula (9). The use of such an azo compound can further improve the polarization performance of the polarizing element.

As a specific example of the azo compound represented by said Formula (9), the following compounds are mentioned, for example.

The azo compound represented by the above formula (9) can be synthesized by, for example, the method described in JP-A-2009-155364 and the like and methods similar thereto, but is not limited thereto. For example, the azo compound represented by the above formula (9) is obtained by reacting the base compound represented by the formula (9-v) described later with a ureating agent such as phenyl chlorocarbonate at 20 to 95 ° C. Can be made. As another synthesis method by ureidation, a method of using a phosgene compound etc. to ureide an amine compound is known. By this synthetic method, the azo compound represented by the formula (9) in the present invention having a ureido skeleton can be obtained.

The specific synthesis method of the azo compound represented by the said Formula (9) is demonstrated below. First, an amine having a substituent as represented by the following formula (9-i) can be prepared, for example, by the method described in Toyo Hosoda “Dye Chemistry”, Tech Journal, 1957, P. 135-234 and By diazotization according to the same production method and then coupling with an aniline represented by the following formula (9-ii), a monoazoamino compound represented by the following formula (9-iii) is obtained.

Wherein (9-i), Ac ₁ has the same meaning as Ac ₁ of the formula (9). Wherein (9-ii), _{Rc 11} and _{Rc 12} represent respectively the same meaning as _{Rc 11} and _{Rc 12} in the formula (9). Wherein (9-iii), Ac ₁ has the same meaning as Ac ₁ of the formula (9), _{Rc 11} and _{Rc 12} each represent the same meaning as _{Rc 11} and _{Rc 12} in the formula (9).

Then, the monoazo amino compound represented by the above formula (9-iii) is diazotized, and further, it is subjected to secondary coupling with an aniline represented by the following formula (9-iv) to give a compound of the following formula (9-v) The disazo amino compound represented is obtained. In the formula (9-iv), _{Rc 13} and _{Rc 14} have the same meanings respectively as _{Rc 13} and _{Rc 14} in the formula (9). Wherein (9-v), Ac ₁ has the same meaning as Ac ₁ of the formula _{_{(9), Rc 11 ~ Rc}} 14 have the same meanings respectively as _{Rc 11} and _{Rc 14} in the formula (9).

The diazotization step in the above reaction route is carried out by a conventional method in which a nitrite such as sodium nitrite is mixed with an aqueous solution of mineral acid such as hydrochloric acid or sulfuric acid or a suspension of diazo component, or Alternatively, it is carried out by the reverse method such as adding nitrite to a weakly alkaline aqueous solution and mixing it with a mineral acid. The temperature for diazotization is preferably -10 to 40.degree. Further, the coupling step with anilines is carried out by mixing an acidic aqueous solution of hydrochloric acid, acetic acid or the like with each of the above diazo solutions, at a temperature of −10 to 40 ° C. and under acidic conditions of pH 2 to 7.

The monoazoamino compound or disazoamino compound obtained by the coupling step may be precipitated as it is or by acid precipitation or salting out and removed by filtration, or it may be subjected to a further step as a solution or suspension. If the diazonium salt is poorly soluble and a suspension, the suspension can be filtered and the diazonium salt after filtration can be used as a presscake in a further coupling step.

Thereafter, the disazo amino compound obtained by the above process is subjected to a ureicidation reaction with phenyl chlorocarbonate to synthesize the azo compound represented by the above formula (9). The ureide reaction is carried out under neutral to alkaline conditions at a temperature of 10 to 90 ° C. and a pH of 7 to 11, for example, according to the production method described in JP-A 2009-155364. After completion of the ureidation reaction, the azo compound obtained by salting out is precipitated and then filtered. When purification is necessary, salting out may be repeated or an azo compound obtained from water may be precipitated 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. Thus, the azo compound represented by the above formula (9) used in the present invention can be synthesized.

Next, equation (10) will be described.

In the above formula (10), Ac ₂ represents a phenyl group or a naphthyl group having at least one substituent selected from the group consisting of a sulfo group and a carboxy group. Each of Rc ₂₁ to Rc ₂₅ independently represents a hydrogen atom, a lower alkyl group, a lower alkoxy group or a lower alkoxy group having a sulfo group. Rc ₂₆ represents a hydrogen atom, a lower alkyl group or a lower alkoxy group having a sulfo group. Xc ₂ is an amino group which may have at least one substituent, a phenylazo group which may have at least one substituent, a naphthotriazole group which may have at least one substituent, or a substituent And the substituent is a lower alkyl group, a lower alkoxy group, a sulfo group, a lower alkylamino group, a hydroxy group, an amino group, a substituted amino group, a carboxy group, and the like. It is selected from the group consisting of carboxyethylamino groups. p and q each independently represent an integer of 0 or 1.

In the above formula (10), Ac ₂ represents a phenyl group having a substituent or a naphthyl group having a substituent, but when Ac ₂ is a phenyl group having a substituent, the phenyl group is sulfo as a substituent It is preferable to have at least one group or a carboxy group, and when the phenyl group has two or more substituents, at least one of the substituents is 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, hydroxy group, nitro group, amino group or substituted amino group In particular, an acetylamino group or an alkylamino group having 1 to 4 carbon atoms is preferable, and the other substituent is preferably a sulfo group, a carboxy group, a methyl group, an ethyl group or a methoxy group. Group, ethoxy group, hydroxy group, more preferably a nitro group, or an amino group, a sulfo group, a carboxy group, and particularly preferably a methyl group, a methoxy group, or ethoxy group. Further, as the alkoxy group having 1 to 4 carbon atoms having a sulfo group, a straight chain alkoxy group is preferable, and the substitution position of the sulfo group is preferably at the end of the alkoxy group. As the alkoxy group having 1 to 4 carbon atoms 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 is preferably 1 or 2, and the position of the substituent on the phenyl group is not particularly limited, but may be only 4-position or a combination of 2-position and 4-position Preferably, it is a combination of 3-position and 5-position.

In the above formula (10), when Ac ₂ 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 those substituents is a sulfo group, and the other substituent is a sulfo group, a hydroxy group, a carboxy group, or an alkoxy group having 1 to 4 carbon atoms having a sulfo group. Further, as the alkoxy group having 1 to 4 carbon atoms having a sulfo group, a straight chain alkoxy group is preferable, and the substitution position of the sulfo group is preferably at the end of the alkoxy group. As the alkoxy group having 1 to 4 carbon atoms 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 sulfo groups on the naphthyl group is 2, the substitution position of the azo group is 2-position, and the substitution position of the sulfo group is a combination of 4-position and 8-position or a combination of 6-position and 8-position It is preferable that it be a combination of 6- and 8-positions. When the number of sulfo groups on the naphthyl group is 3, the substitution position of the sulfo group is particularly preferably a combination of 1-position, 3-position and 6-position, with the substitution position of the azo group as the 2-position.

In the above formula (10), Xc ₂ has an amino group which may have at least one substituent, a phenylamino group which may have at least one substituent, at least one substituent Optionally substituted phenylazo group, naphthotriazole group optionally having at least one substituent group, benzoyl group optionally having at least one substituent group, or even having at least one substituent group Is preferably a phenylamino group which may have a substituent, a phenylazo group which may have a substituent, a naphthotriazole group which may have a substituent, and a substituent. which may be a benzoyl group, or a substituent include good benzoylamino group, a particularly preferred Xc _2, phenyl amino group which may have a substituent, which may have a substituent There phenylazo group, and a benzoylamino group that may have a substituent. The substituent is selected from the group consisting of a lower alkyl group, a lower alkoxy group, a sulfo group, a lower alkylamino group, a hydroxy group, an amino group, a substituted amino group, a carboxy group, and a carboxyethylamino group.

When Xc ₁ is an amino group which may have at least one substituent, the amino group may be unsubstituted, preferably a lower alkyl group, a lower alkoxy group, a sulfo group, an amino group, It has one or two substituents selected from the group consisting of a substituted amino group and a lower alkylamino group, more preferably a group consisting of a methyl group, a methoxy group, a sulfo group, an amino group and a lower alkylamino group And one or two substituents selected from

When Xc ₁ is a phenylamino group which may have at least one substituent, the phenylamino group is unsubstituted or preferably a lower alkyl group, a lower alkoxy group, a sulfo group And one or two substituents selected from the group consisting of amino and lower alkylamino, more preferably a substituent selected from the group consisting of methyl, methoxy, sulfo and amino Have one or two.

When Xc ₁ is a phenylazo group which may have at least one substituent, the phenylazo group is unsubstituted, or preferably, a hydroxy group, a lower alkyl group, a lower alkoxy group, amino And one to three substituents selected from the group consisting of carboxyethylamino group, more preferably, one to three substituents selected from the group consisting of methyl group, methoxy group, amino and hydroxy group Have one.

When Xc ₁ is a naphthotriazole group which may have at least one substituent, the naphthotriazole group is unsubstituted or preferably composed of a sulfo group, an amino group and a carboxy group It has one or two substituents selected from the group, more preferably one or two sulfo groups as substituents.

When Xc ₁ is a benzoylamino group which may have at least one of the above-mentioned substituents, the benzoylamino group is unsubstituted or, preferably, a hydroxy group, an amino group and carboxyethylamino It has one substituent selected from the group consisting of groups, and more preferably has one or two hydroxy or amino groups as substituents.

When Xc ₁ is a benzoyl group which may have at least one substituent, the benzoyl group is unsubstituted or preferably composed of a hydroxy group, an amino group and a carboxyethylamino group It has one substituent selected from the group, and more preferably has one or two hydroxy groups or amino groups as substituents.

Further preferable examples of Xc ₂ include the following.
An amino 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, an amino group, and an alkylamino group having 1 to 4 carbon atoms,
・ Phenylamino group optionally having one or two substituents selected from the group consisting of hydrogen atom, methyl group, methoxy group, sulfo group, amino group, and alkylamino group having 1 to 4 carbon atoms,
Benzoyl group which may have one substituent selected from the group consisting of amino group and carboxyethylamino group,
Benzoylamino group optionally having one substituent selected from the group consisting of hydrogen atom, amino group and carboxyethylamino group, or hydrogen atom, hydroxy group, methyl group, methoxy group, amino group And a phenylazo group optionally having 1 to 3 substituents selected from the group consisting of a carboxyethylamino group.
The position of the substituent is not particularly limited. For example, when Xc ₂ is a phenylamino group, it is particularly preferable that at least one of the substituents on the phenyl group is the p-position of the phenyl group with respect to the amino group. .

In the above formula (10), each of Rc ₂₁ to Rc ₂₅ independently represents a hydrogen atom, a lower alkyl group, a lower alkoxy group or a lower alkoxy group having a sulfo group. Each of Rc ₂₁ to Rc ₂₅ is preferably independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, or a linear alkoxy group having a sulfo group at the terminal, A hydrogen atom, methyl group, ethyl group, methoxy group, ethoxy group, 3-sulfopropoxy group, or 4-sulfobutoxy group is more preferable, and a hydrogen atom, methyl group, methoxy group or 3-sulfopropoxy group is preferable. Being particularly preferred.

In the above formula (10), Rc ₂₆ represents a hydrogen atom, a lower alkyl group or a lower alkoxy group having a sulfo group. It is preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a linear alkoxy group having a sulfo group at the terminal, and a hydrogen atom, a methyl group, an ethyl group, a 3-sulfopropoxy group, or a 4-sulfobutoxy group More preferably, it is a hydrogen atom, a methyl group or a 3-sulfopropoxy group.

In the above formula (10), p and q are each independently an integer of 0 or 1. In order to obtain good polarization performance in the polarizing element of the present invention, when either one of p and q is 0, the other is preferably 1, and more preferably p and q are 1.

Among the azo compounds represented by the above formula (10), an azo compound represented by the following formula (10b) is preferable. The use of such an azo compound can further improve the polarization performance of the polarizing element. In the formula (10b), Ac ₂ , Rc ₂₁ to Rc ₂₆ , Xc ₂ , p and q are as defined in the above formula (10)

Next, specific examples of the azo compound in which the form of the free acid is represented by Formula (10) will be given below. In the following compound examples, the sulfo group and the hydroxy group are represented in the form of free acid, but the sulfo group and the hydroxy group may be in the form of a salt.

As a synthesis method of the azo compound in which the form of the free acid is represented by the formula (10), for example, JP-A-9-302250, JP-A-3-12606, WO 2005/075572, WO Examples thereof include, but are not limited to, the methods described in 2012/108169 and WO 2012/108173. As an azo compound in which the form of a free acid is represented by Formula (10), for example, C.I. I. Direct Red 117, C.I. I. Direct Red 127, azo compounds described in JP-A-3-12606, azo compounds described in WO 2005/075572, azo compounds described in WO 2012/108169, etc. Can be mentioned

In one aspect, the polarizing element of the present invention further includes the azo compound represented by the above formula (11), a metal complex compound thereof, or a salt thereof, or the azo compound represented by the formula (12) or a salt thereof.

The compound shown in Formula (11) will be described.

In formula (11), Ab ₁ represents a phenyl group or a naphthyl group having at least one substituent selected from the group consisting of a sulfo group and a carboxy group, and Rb ₁₁ to Rb ₁₄ each independently represent hydrogen R b ₁₅ and R b ₁₆ each independently represent a lower alkoxy group, and X b ₁ represents a lower alkyl group, a lower alkoxy group, a sulfo group, a sulfo group, or a sulfo group. Group optionally having at least one substituent selected from the group consisting of a group, an amino group, a lower alkylamino group, a hydroxy group, a carboxy group and a carboxyethylamino group, which may have a substituent A phenylamino group, a phenylazo group which may have a substituent, a naphthotriazole group which may have a substituent, or a substituent Represents a benzoylamino group or a benzoyl group which may have a substituent. d represents an integer of 0 or 1; In addition, the compound may be a metal complex compound, preferably a copper complex compound.

The copper complex compound refers to, for example, the following formula (11b), M in the formula (11b) is a metal, and copper, nickel, cobalt and the like are used, preferably copper. In the formula (11b), Ab ₁ , Rb ₁₁ to Rb ₁₄ , Rb ₁₆ , Xb ₁ and d each have the same meaning as in the above formula (11).

When Ab ₁ is a phenyl group in the above formulas (11) and (11 b), it is preferable to have at least one sulfo group or carboxy group as a substituent. When the phenyl group has two or more substituents, at least one of the substituents is a sulfo group or a carboxy group, and the other substituent is preferably a sulfo group, a carboxy group, a lower alkyl group or a lower alkoxy group. And a lower alkoxy group having a sulfo group, a hydroxy group, a nitro group, a benzoyl group, an amino group, an acetylamino group and a lower alkylamino group substituted amino group, more preferably a sulfo group, a methyl group or an ethyl group. It is selected from the group consisting of a group, methoxy group, ethoxy group, hydroxy group, carboxy group, nitro group, amino group, 3-sulfopropoxy group and 4-sulfobutoxy group, and particularly preferably sulfo group, methyl group, methoxy group , A carboxy group and a 3-sulfopropoxy group. As the lower alkoxy group having a sulfo group, linear alkoxy is preferable as in the above-mentioned 3-sulfopropoxy group or 4-sulfobutoxy group, and the substitution position of the sulfo group is at the end of the alkoxy group preferable. It is preferable that the phenyl group has a sulfo group as a substituent, and the number of sulfo groups is preferably one or two. The substitution position of the substituent is not particularly limited, but when the position of the azo group is 1-position, 4-position of the phenyl group is preferable, and when there are two sulfo groups, the phenyl group is Preferred is a combination of 2- and 4-positions or a combination of 3- and 5-positions.

In formulas (11) and (11b), when Ab ₁ is a naphthyl group, it is preferable to have at least one sulfo group as a substituent. When the naphthyl group has two or more substituents, at least one of the substituents is a sulfo group, and the other substituent is preferably a sulfo group, a hydroxy group, a carboxy group and a lower alkoxy having a sulfo group. It is selected from the group consisting of The lower alkoxy group having a sulfo group is preferably a linear alkoxy group, and the substitution position of the sulfo group is preferably at the end of the alkoxy group. The lower alkoxy group having such a sulfo group is more preferably a 3-sulfopropoxy group or a 4-sulfobutoxy group, and particularly preferably a 3-sulfopropoxy group. When the number of sulfo groups substituted for the naphthyl group is two, the substitution position of the sulfo group is the combination of 4-, 8-position or 6-, 8-position of the naphthyl group with the position of the azo group as the 2-position. A combination of 6- and 8-positions is more preferred. When the number of sulfo groups substituted for the naphthyl group is three, it is preferable that the position of the azo group be 2-position and the substitution position of the sulfo group be a combination of 3-, 6- and 8-positions.

In the above formulas (11) and (11b), each of Rb ₁₁ to Rb ₁₄ independently represents a hydrogen atom, a lower alkyl group, a lower alkoxy group or a lower alkoxy group having a sulfo group. The lower alkoxy group having a sulfo group is preferably a linear alkoxy group, and the substitution position of the sulfo group is preferably at the end of the alkoxy group. Rb ₁₁ to Rb ₁₄ are preferably a hydrogen atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group, a 3-sulfopropoxy group or a 4-sulfobutoxy group, and particularly preferably a sulfo group, a methyl group or a methoxy group. A carboxy group or a 3-sulfopropoxy group.

_{Rb 15} and _{Rb 16} in the above formula (11), _{Rb 16} in the formula (11b) are each independently represents a lower alkoxy group, preferably a methoxy group or an ethoxy group. The methoxy group is more preferable because the polarization performance of the polarizing element or polarizing plate according to the present invention is dramatically improved.

In the above formulas (11) and (11b), Xb ₁ has at least one substituent selected from the group consisting of a lower alkyl group, a lower alkoxy group, a sulfo group, an amino group and a lower alkylamino group. Amino group, phenylamino group which may have a substituent, phenylazo group which may have a substituent, naphthotriazole group which may have a substituent, or benzoyl which may have a substituent It represents an amino group or a benzoyl group which may have a substituent.

When Xb ₁ is an amino group which may have the above-mentioned substituent, the amino group may be unsubstituted, preferably a lower alkyl group, a lower alkoxy group, a sulfo group, an amino group and a lower alkyl. It has one or two substituents selected from the group consisting of amino groups, more preferably a substituent selected from the group consisting of methyl group, methoxy group, sulfo group, amino group and lower alkylamino group I have one or two.

When Xb ₁ is a phenylamino group which may have the above-mentioned substituent, the phenylamino group is unsubstituted or preferably a lower alkyl group, a lower alkoxy group, a sulfo group, amino And one or two substituents selected from the group consisting of lower alkylamino groups, more preferably a substituent selected from the group consisting of methyl groups, methoxy groups, sulfo groups and amino groups There are one or two.

When Xb ₁ is a phenylazo group which may have the above-mentioned substituent, the phenylazo group is unsubstituted or, preferably, a hydroxy group, a lower alkyl group, a lower alkoxy group, an amino group and It has 1 to 3 substituents selected from the group consisting of carboxyethylamino groups, and more preferably has 1 to 3 substituents selected from the group consisting of methyl, methoxy, amino and hydroxy groups .

When Xb ₁ is a naphthotriazole group which may have the above-mentioned substituent, the naphthotriazole group is unsubstituted or, preferably, from the group consisting of a sulfo group, an amino group and a carboxy group It has one or two substituents selected, and more preferably one or two sulfo groups as substituents.

When Xb ₁ is a benzoylamino group which may have the above-mentioned substituent, the benzoylamino group is unsubstituted or preferably composed of a hydroxy group, an amino group and a carboxyethylamino group. It has one substituent selected from the group, and more preferably has one or two hydroxy groups or amino groups as substituents.

Xb ₁ is preferably a benzoylamino group or a phenylamino group which may have at least one of the above substituents, and most preferably a phenylamino group which may have the above substituents . When the benzoylamino group or the phenylamino group has the above-mentioned substituent, the position of the substituent is not particularly limited, but in the case of the phenylamino group, one of the above-mentioned substituents is p- Preferably, in the case of a benzoylamino group, one of the above substituents is p-position to the carbonyl group.

Among the azo compounds represented by the above formula (11), an azo compound represented by the following formula (11c) is preferable, and the polarization performance of the polarizing element can be further improved by using such an azo compound. In the formula (11c), Ab ₁ , Rb ₁₁ to Rb ₁₆ , Xb ₁ and d are as defined in the above-mentioned formula (11).

As specific examples of the azo compounds represented by the above formulas (11), (11b) and (11c), for example, JP-A-3-12606, JP-A-5-295281, JP-A-10-259311, The following azo compounds as described in WO 2007/145210, WO 2012/108169, and WO 2012/108173 and the like can be mentioned.

The azo compounds represented by the above formulas (11), (11b) and (11c) are, for example, disclosed in JP-A-3-12606, JP-A-5-295281, JP-A-10-259311, and International Publication No. Although it can manufacture by the method described in 2007/145210, WO2012 / 108169, and WO2012 / 108173 grade | etc., It is not limited to these.

Then, the azo compound represented by the said Formula (12) is demonstrated.

In formula (12), Ab ₂ represents a phenyl group or a naphthyl group having at least one substituent selected from the group consisting of a sulfo group and a carboxy group, and Rb ₂₁ represents a hydrogen atom, a lower alkyl group or a lower alkoxy group Or a lower alkoxy group having a sulfo group, and Xb ₂ is a substituent selected from the group consisting of a lower alkyl, a lower alkoxy group, a lower alkylamine group, a hydroxy group, a carboxy group, a sulfo group, an amino group and a substituted amino group An amino group which may have at least one group, a phenylamino group which may have a substituent, a phenylazo group which may have a substituent, a naphthotriazole group which may have a substituent, a substituent Represents a benzoylamino group which may have or a benzoyl group which may have a substituent)

In Formula (12), Ab ₂ represents a phenyl group or a naphthyl group having at least one substituent selected from the group consisting of a sulfo group and a carboxy group, and the phenyl group or the naphthyl group has two substituents. When it has one or more substituents, at least one of the substituents is a sulfo group or a carboxy group, and the other substituents are preferably sulfo, lower alkyl, lower alkoxy, lower alkoxy having sulfo, carboxy It is selected from the group consisting of group, nitro group, amino group and substituted amino group, more preferably selected from the group consisting of sulfo group, methyl group, ethyl group, methoxy group, ethoxy group, carboxy group, nitro group and amino group Most preferably, it is selected from the group consisting of a sulfo group, a carboxy group, a lower alkyl group and a lower alkoxy group. The lower alkoxy group having a sulfo group is preferably a linear alkoxy group, and the substitution position of the sulfo group is preferably at the end of the alkoxy group. The lower alkoxy group having such a sulfo group is more preferably a 3-sulfopropoxy group or a 4-sulfobutoxy group, and particularly preferably a 3-sulfopropoxy group. Further, the number of substituents which a phenyl group has is preferably one or two, while the number of substituents which a naphthyl group has is preferably two or three. The positions of these substituents are not particularly limited, but when the number of substituents that the phenyl group has is one, the 4-position of the phenyl group is the 1-position of the azo group. Preferably, when the number of substituents is two, a combination of 2- and 4-positions or a combination of 3- and 5-positions of a phenyl group is preferred. On the other hand, it is preferable that the naphthyl group has two or three sulfo groups as a substituent, and when the number of sulfo groups substituted by the naphthyl group is two, the substitution position of the sulfo group is naphthyl A combination of 4- and 8-positions or a combination of 6- and 8-positions is preferred, where the substitution position of the azo group of the group is 2-position, and a combination of 6- and 8-positions is more preferred. When the number of sulfo groups substituted by a naphthyl group is three, the substitution position of the sulfo group is a combination of 3-, 6-, and 8-positions with the substitution position of the azo group as the 2-position. preferable.

In the above formula (12), Rb ₂₁ represents a hydrogen atom, a lower alkyl group, a lower alkoxy group or a lower alkoxy group having a sulfo group. The lower alkoxy group having a sulfo group is preferably a linear alkoxy group, and the substitution position of the sulfo group is preferably at the end of the alkoxy group. Rb ₂₁ is more preferably a hydrogen atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group, a 3-sulfopropoxy group or a 4-sulfobutoxy group, particularly preferably a sulfo group, a methyl group or a methoxy group, It is a carboxy group or a 3-sulfopropoxy group. In particular, when Rb ₂₁ is a methoxy group, it is preferable because the polarization performance of the polarizing element or the polarizing plate according to the present invention is dramatically improved.

In the above formula (12), Xb ₂ represents at least one substituent selected from the group consisting of lower alkyl, lower alkoxy, lower alkylamine, hydroxy, carboxy, sulfo, amino and substituted amino. Or at least one substituent selected from the group consisting of hydrogen, lower alkyl, lower alkoxy, hydroxy, carboxy, sulfo, amino and substituted amino. And an optionally substituted phenylamino group, a phenylazo group, a naphthotriazole group or a benzoylamino group.

When Xb ₂ is an amino group which may have the above-mentioned substituent, the amino group may be unsubstituted, preferably a hydroxy group, a carboxy group, a sulfo group, an amino group and a lower alkylamino group And one or two substituents selected from the group consisting of, more preferably one substituent selected from the group consisting of methyl, methoxy, sulfo, amino and lower alkylamino. Or it is good to have two.

When Xb ₂ is a phenylamino group which may have the above-mentioned substituent, the phenylamino group is unsubstituted or a methyl group, a methoxy group, an amino group, a substituted amino group, and sulfo. It has a substituent selected from the group consisting of groups, and preferably has a methoxy group as an unsubstituted or substituted group. When the phenylamino group has the above-mentioned substituent, the position of the substituent is not particularly limited, but one of the above-mentioned substituents is at the p-position relative to the amino group bonded to the phenyl group. Is preferred.

When Xb ₂ is a benzoylamino group which may have the above-mentioned substituent, the benzoylamino group is unsubstituted or selected from the group consisting of an amino group, a substituted amino group, and a hydroxy group. And preferably have an amino group as a substituent. When the benzoylamino group has the above-mentioned substituent, the position of the substituent is not particularly limited, but one of the above-mentioned substituents is p-position relative to the carbonyl group bonded to the phenyl group. Is preferred.

When Xb ₂ is a phenylazo group which may have the above-mentioned substituent, the phenylazo group is unsubstituted or a group consisting of a hydroxy group, an amino group, a methyl group, a methoxy group and a carboxy group And more preferably a hydroxy group as a substituent.

When Xb ₂ is a naphthotriazole group which may have the above-described substituent, the phenylazo group is unsubstituted or has a sulfo group as a substituent.

Among the azo compounds represented by the above formula (12), an azo compound represented by the following formula (12b) is preferable, and the polarization performance of the polarizing element can be further improved by using such an azo compound.

In formula (12b), Ab ₂ , Rb ₂₁ and Xb ₂ are each as defined in the above formula (12).

As a specific example of an azo compound represented by such Formula (12), the following azo compounds are mentioned, for example.

The azo compound represented by the above formula (12) can be produced by, for example, known diazotization and coupling as described in JP-B-64-5623 and JP-A-5-53014. Although it can be done, it is not limited to these.

In the polarizing element, the content of the azo compound represented by the formula (11) or the formula (12) or a salt thereof is preferably 0.0001 to 5 parts by mass with respect to 100 parts by mass of the aqueous solution. Preferably, it is 0.001 to 1 part by mass.

In one aspect, the polarizing element of the present invention preferably contains at least one of the azo compound represented by the following formula (13) or (13 ′) or a salt thereof in order to further improve the polarization performance.

In the above formula (13), Ay ₁ is a hydrogen atom, a sulfo group, a carboxy group, a hydroxy group, a lower alkyl group or a lower alkoxy group, preferably a sulfo group or a carboxy group. Each of Ry ₁ to Ry ₄ independently represents a hydrogen atom, a sulfo group, a lower alkyl group, a lower alkoxy group, or a lower alkoxy group having a sulfo group, preferably a hydrogen atom, a sulfo group, a lower alkyl group or a lower alkoxy group. And more preferably a hydrogen atom, a methyl group or a methoxy group. j represents an integer of 1 to 3;

In the above formula (13 ′), i is 0 or 1. Ay ₁ , Ay ₂ , Ry ₁ , Ry ₂ , and j have the same meaning as in Formula (13).

In formula (13 ′), Ay ₁ and Ay ₂ are preferably a sulfo group, a carboxy group or a lower alkoxy group, more preferably a sulfo group, a carboxy group, a methoxy group or an ethoxy group, and still more preferably , A sulfo group or a carboxy group.

In formula (13 ′), Ry ₁ and Ry ₂ are preferably a hydrogen atom, a sulfo group, a methyl group, an ethyl group, a methoxy group or an ethoxy group, and more preferably a hydrogen atom, a sulfo group, a methyl group or It is a methoxy group.

Among the azo compounds represented by the above formula (13) or (13 ′), an azo compound represented by the following formula (13b) is particularly preferable, and the polarization performance of the polarizing element It can be improved more. In formula (13b), Ay ₁ , Ry ₁ , Ry ₂ are as defined in the above formula (13)

In a preferred embodiment, the azo compound represented by the formula (13) or (13 ') may be used together with the azo compound represented by the formula (5) or the formula (6).

In the polarizing element, the content of the azo compound represented by the formula (13) or (13 ′) or the salt thereof is 100 parts by mass of the azo compound of the formula (5) or (6), The amount is preferably 0.01 to 300 parts by mass, more preferably 0.1 to 200 parts by mass, and still more preferably 30 to 200 parts by mass.

The azo compounds represented by the above formulas (13) and (13 ') affect the transmittance of 400 to 500 nm. In the polarizing element, in particular, the transmittance on the short wavelength side of 400 to 500 nm and the degree of polarization (dichroism) have an influence on the blue loss at the time of black display and the yellowing of white at the time of white display. The azo compounds represented by the formulas (13) and (13 ′) improve the polarization characteristics (dichroism) of 400 to 500 nm while suppressing the decrease in the transmittance on the short wavelength side at the parallel position of the polarizing element. The yellowishness at the time of white display and the omission of blue at the time of black display can be further reduced. The polarizing element further contains an azo compound represented by the formula (13) or (13 ′), so that it is more achromatic by itself, particularly in the range of 30 to 65% of the single transmittance after the visibility correction. When white is displayed, white color such as high quality paper is expressed, and when the single transmittance after the visibility correction is 35 to 45% in particular, the degree of polarization or the contrast is improved, which is preferable.

Specific examples of the azo compounds represented by the formulas (13) and (13 ') include C.I. I. Direct Yellow 4, C.I. I. Direct Yellow 12, C.I. I. Direct Yellow 72, and C.I. I. Examples thereof include, but are not limited to, Direct Orange 39, and azo compounds having a stilbene structure described in WO 2007/138980 and the like.

Further specific examples of the azo compounds represented by the formulas (13) and (13 ′) will be given below. The compound examples are shown in the form of free acid.

The azo compounds represented by the formulas (13) and (13 ′) or salts thereof can be synthesized, for example, by the method described in, for example, WO 2007/138980, etc. it can.

The polarizing element of the present invention may contain other azo compounds for the purpose of color correction to the extent that the performance according to the present invention is not impaired. As another azo compound to be contained, one having high dichroism is particularly preferable. For example, an azo compound as shown in Non-Patent Document 1, C.I. I. Direct. Yellow 12, C.I. I. Direct Yellow 28, C.I. I. Direct. Yellow 44, C.I. I. Direct. Orange 26, C.I. I. Direct. Orange 39, C.I. I. Direct. Orange 107, 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, and azo compounds described in JP-A-2001-33627, JP-A-2002-296417, and JP-A-60-156759. In particular, an azo compound having phenyl J acid in a trisazo structure can be suitably used. It is preferable to use such other azo compounds together with the azo compound represented by the formula (1) or a salt thereof for the polarizing element. The above-mentioned other azo compounds can be used as alkali metal salts (for example, sodium salts, potassium salts, lithium salts), ammonium salts, salts of amines, or copper complex compounds or salts thereof, as well as free acids. The above-mentioned other azo compounds are not limited to these, and known azo compounds having dichroism can be used. Inclusion of other azo compounds in the form of a free acid, a salt thereof or a copper complex salt thereof makes it possible in particular to improve the optical properties. The other azo compounds may be used alone or in combination of two or more.

In one aspect, the polarizing element of the present invention has improved heat resistance and durability by containing iodine. When iodine is contained in the substrate, it is difficult to dissolve in a solvent with iodine alone, and it is difficult to impregnate into the substrate, so potassium iodide, ammonium iodide, copper iodide, copper iodide, sodium iodide, calcium iodide, cobalt iodide, It is common to include iodides such as zinc iodide and chlorides such as sodium chloride, lithium chloride and potassium chloride together with iodine. When the polarizing element is produced using the above-mentioned iodide, a polarizing element having a high degree of polarization in the visible region centered on around 480 nm and around 600 nm can usually be produced.

In one aspect, the polarizing element of the present invention may contain iodine, whereby, for example, the single transmittance after luminosity correction can be 35 to 50% and can have a high degree of polarization, that is, contrast. It has the characteristics of high durability, particularly heat resistance, low optical characteristics, particularly little color change, and small change in transmittance, while having high transmittance and high contrast, which are the characteristics of an iodine-based polarizing plate be able to.

(Base material)
The substrate used for producing the polarizing element is not particularly limited as long as it can contain a dichroic dye such as an infrared light-absorbing water-soluble compound, and for example, it is formed of a hydrophilic polymer And molded articles. Examples of hydrophilic polymers include polyvinyl alcohol resins, amylose resins, starch resins, cellulose resins, and polyacrylate resins. When a dichroic dye such as an infrared light-absorbing water-soluble compound is contained in a substrate, it is most preferable to use a polyvinyl alcohol-based resin as the substrate from the viewpoint of processability, dyeability and crosslinkability. The shape of the substrate is not particularly limited, but is preferably in the form of a film.

(Transmittance)
In the difference of the average transmittances of the two wavelength bands, in the polarizing element of the present invention, it is preferable that the absolute value of the difference of the average transmittances between the specific wavelength bands is equal to or less than a predetermined value. The average transmittance is an average value of the transmittance of each wavelength in a specific wavelength band.

In one aspect, the polarizing element of the present invention has an average value of the transmittance of each wavelength at 520 nm to 590 nm and a transmittance of each wavelength at 420 nm to 480 nm when measured with the absorption axes of two polarizing elements in parallel. The absolute value of the difference from the average value is 5% or less, and the absolute value of the difference between the average of the transmittance of each wavelength at 600 nm to 640 nm and the average of the transmittance of each wavelength at 520 nm to 640 nm is 3 It is characterized by being less than%.

(Transmittance after visibility correction)
The transmittance after the visual sensitivity correction is the transmittance after the visual sensitivity correction, which is obtained according to JIS Z 8722: 2009. The measurement of the transmittance used for correction is, for a measurement sample (for example, a polarizing element or a polarizing plate), a spectral light transmittance every 5 nm or 10 nm for each wavelength of 400 to 700 nm using a C light source (2 degrees visual field) Can be determined by correcting it to the luminosity according to JIS Z 8722: 2009. The transmittance after luminosity correction is the single transmittance after luminosity correction when the polarizing element or the polarizing plate is measured alone, or the absorption axis is made parallel by using two polarizing elements or two polarizing plates. Corrects the transmissivity when the absorption axis is orthogonal to the transmissivity when the transmissivity at the time of illumination is corrected to the visibility, the parallel position transmissivity after luminosity correction, and two absorption elements using two polarizing elements or polarizing plates There is orthogonal position transmissivity after visual sensitivity correction in the case of

Wavelength bands of 420 nm to 480 nm, 520 nm to 590 nm, and 600 nm to 640 nm are main wavelength bands based on the color matching function used in calculation when showing a color in JIS Z 8781-4: 2013. Specifically, in the XYZ color matching function of JIS Z 8701 based on JIS Z 8781-4: 2013, x (λ) with 600 nm as the maximum value, y (λ) with 550 nm as the maximum value, 455 nm When the maximum value of z (λ) as the maximum value is 100, the respective wavelengths showing values of 20 or more are wavelength bands of 420 nm to 480 nm, 520 nm to 590 nm, and 600 nm to 640 nm.

The transmittance obtained by measurement in a state in which two polarizing elements are arranged so as to be parallel to each other in the absorption axis direction (during bright display or white display) is also referred to as “parallel transmittance”. In addition, the average transmittance of each wavelength of nm nm to nm nm is also referred to as " _AT-- ". In one embodiment of the polarizing element of the present invention, the difference between AT _420-480 and AT _{520-590 in} _{terms of} parallel transmittance is 5.0% or less as an absolute value, preferably 3.5% or less, more preferably Is preferably at most 2.5%, more preferably at most 2.0%, particularly preferably at most 1.5%. In one embodiment, the difference between AT _520-590 and AT _{600-640 in} _{terms of} parallel transmittance is 3.0% or less as an absolute value, preferably 2.0% or less, more preferably 1.5 % Or less, more preferably 1.0% or less. Such a polarizing element can display high-quality paper-like white color at a parallel position.

The transmittance obtained by measurement in a state in which two polarizing elements are arranged so as to be orthogonal to each other in the absorption axis direction (black display or dark display) is also referred to as “orthogonal transmittance”. In one embodiment of the polarizing element of the present invention, preferably, the difference between AT _420-480 and AT _520-590 is 3.0% or less as an absolute value, and _orthogonal to the _{transmissivity} , , The difference between AT _600-640 is 2.0% or less as an absolute value. Such a polarizing element can display achromatic black at the orthogonal position. Furthermore, regarding orthogonal position transmittance, the difference between AT _420-480 and AT _520-590 as an absolute value is more preferably 1.5% or less, still more preferably 1.0% or less, particularly preferably 0.5 % Or less. The difference between AT _520-590 and AT _600-640 is preferably 1.5% or less, more preferably 1.0% or less, particularly preferably 0.5% or less as an absolute value, with respect to orthogonal position transmittance. It is.

Furthermore, the single transmittance of each wavelength, the parallel transmittance of each wavelength, and the average transmittance of the orthogonal transmittance of each wavelength in each of wavelength bands 380 nm to 420 nm, 480 nm to 520 nm, and 640 nm to 780 nm are When the average transmittance of each wavelength in the wavelength band of 420 nm to 480 nm, 520 nm to 590 nm, and 600 nm to 640 nm is adjusted as described above, it is difficult to greatly affect the dye, but adjusted to some extent preferable. For single transmittance of each _wavelength, it is preferable that the difference between the _{AT 380-420} and _{AT 420-480} is 15% or less as an absolute _value, the difference between the _{AT 480-520} and _{AT 420-480} as the absolute value 15 % or _{less, aT 480-520} a difference between the _{aT 520-590} 15% or less as an absolute _value, and the difference between the _{aT 640-780} and _{aT 600-640} is 20% or less as an absolute value.

In one aspect, the polarizing element according to the present invention preferably has a single transmittance of 30% to 65% after the visibility correction. The single transmittance after the visibility correction is the transmittance corrected to the visibility according to JIS Z 8722: 2009 for one measurement sample (for example, a polarizing element or a polarizing plate). As the performance of the polarizing plate, one having a higher transmittance is required, but if the single transmittance after the visibility correction is 30% to 65%, the brightness can be expressed without discomfort even when used in a display device. The higher the transmittance, the lower the degree of polarization, so from the viewpoint of the balance of the degree of polarization, the single transmittance after visual sensitivity correction is more preferably 35% to 50%, and still more preferably 37 % To 47%, particularly preferably 38% to 45%. The degree of polarization may decrease if the single transmittance after luminosity correction exceeds 65%, but if the light transmittance of the polarizing element or specific polarization performance or contrast is to be determined, it may be after luminosity correction. The single transmittance may exceed 65%.

It is _desirable that AT _520-590 be 25% to 50% in the parallel transmittance in the polarizing element. When provided in a display device, such a polarizing element can be a bright and clear display device with high luminance. The transmittance of each wavelength in the wavelength band of 520 nm to 590 nm is one of the main wavelength bands based on the color matching function used in calculation when showing a color in JIS Z 8781-4: 2013. In particular, each wavelength band of 520 nm to 590 nm is the wavelength band with the highest visibility based on the color matching function, and the transmittance in this range is close to the transmittance that can be visually confirmed. Therefore, it is very important to adjust the transmittance of each wavelength in the wavelength band of 520 nm to 590 nm. The AT _520-590 measured in the parallel position is more preferably 28% to 45%, still more preferably 30% to 40%. Furthermore, the polarization degree of the polarizing element at this time may be 80% to 100%, preferably 90% to 100%, more preferably 97% to 100%, still more preferably 99% or more, and in particular Preferably it is 99.5% or more. The higher the degree of polarization, the better. However, in the relationship between the degree of polarization and the transmittance, the degree of polarization and transmittance should be adjusted to a suitable degree of transmittance and degree of polarization depending on whether the importance is on brightness or the degree of polarization (or contrast). Can.

The single transmittance after the visibility correction is the single transmittance subjected to the visibility correction by the 2 ° field of view (C light source). The single transmittance after correction of visibility is calculated for each wavelength of 400 to 700 nm for every 5 nm or 10 nm for one measurement sample (for example, polarizing element or polarizing plate), and the 2 ° field of view It can obtain | require by performing visual sensitivity correction | amendment by C light source.

(Degree of polarization)
The polarizing element of the present invention has polarization performance for light in a partial or entire wavelength range of at least 700 nm to 1400 nm.

The degree of polarization of the polarizing element of the present invention is not particularly limited, but if the degree of polarization is 80% to 100%, it can be used for general purpose applications as a general polarizing element. The degree of polarization is preferably 90% or more. If the polarization degree of the polarizing element is 90% or more, the polarization function can be expressed even when used in a liquid crystal display device. The degree of polarization is preferably 99% or more, more preferably 99.9% or more, and still more preferably 99.95% or more. However, the application of the degree of polarization does not have to be 99% because the application used for the relationship between brightness (transmittance) and contrast (degree of polarization) differs, and the degree of polarization is set according to the requirement, It can be used.

(Chromaticity)
The chromaticity a * value and the b * value are values determined at the time of natural light transmittance measurement according to JIS Z 8781-4: 2013. The display method of the object color defined in JIS Z 8781-4: 2013 corresponds to the display method of the object color defined by the International Commission on Illumination (abbr .: CIE). The measurement of the chromaticity a * value and the b * value is performed by irradiating the measurement sample (for example, a polarizing element or a polarizing plate) with natural light. In the following, the chromaticity a * value and the b * value determined for one measurement sample are a * -s and b * -s, and two measurement samples are arranged so that the absorption axis directions are parallel to each other. The chromaticity a * and b * values determined for the state (white display) are a * -p and b * -p, and two measurement samples are arranged with their absorption axis directions orthogonal to each other (black display The chromaticity a * values and b * values determined for time) are denoted as a * -c and b * -c.

In one aspect, in the polarizing element according to the present invention, each of the absolute values of a * -s and b * -s is preferably 1.0 or less, and the absolute values of a * -p and b * -p It is preferable that each is 2.0 or less. Such a polarizing element is neutral by itself and can display high-quality white when displaying white. The absolute values of a * -p and b * -p of the polarizing element are each independently more preferably 1.5 or less, still more preferably 1.0 or less. Furthermore, in the polarizing element, the absolute values of a * -c and b * -c are preferably 3.0 or less, more preferably each independently 2.0 or less, still more preferably 1.0 or less. It is. Such a polarizing element can display achromatic black when displaying black. A human being can perceive a difference in color even if there is a difference of 0.5 in absolute values of the chromaticity a * value and the b * value, and some people may feel a large difference in color. For this reason, it is very important to control these values in the polarizing element. In particular, when the absolute values of a * -p, b * -p, a * -c, and b * -c are respectively 1.0 or less, white and black are displayed when white is displayed. A good polarizing plate can be obtained in which the other colors can hardly be confirmed in black. Such a polarizing plate can realize an achromatic color at a parallel position, that is, a white color like high-grade paper, and can realize a clear black color having an achromatic color at a cross position.

In one aspect, the polarizing element according to the present invention has single color achromaticity and high degree of polarization while having high contrast and high transmittance. The polarizing element of the present invention can express high quality paper-like white (paper white) at the time of white display, and can express an achromatic black at the time of black display, in particular a clear black with a high-grade feeling . Heretofore, no polarizing element having such high transmittance and achromatic color, and absorption performance in the infrared region and further polarization performance in the infrared region has not existed. The polarizing element of the present invention is further characterized in that it is highly durable and particularly resistant to high temperature and high humidity.

[Method of Manufacturing Polarizing Element]
Hereinafter, a specific method of manufacturing a polarizing element will be described by taking a polyvinyl alcohol-based resin film as an example of a substrate. The polarizing element is produced, for example, of a polyvinyl alcohol resin, preparation of an original film, swelling treatment, dyeing treatment, first washing treatment, treatment containing a crosslinking agent and / or a water resistance agent, stretching treatment, second washing treatment , Manufactured by sequentially performing a drying process. Note that some of these processes can be omitted.

In the preparation method of the polarizing element, the swelling degree of the base material in the swelling step to be described later, the blending ratio of each azo compound in the dyeing step, the temperature of the dyeing solution, pH, types of sodium chloride, sodium sulfate, sodium tripolyphosphate etc. The concentration, and the dyeing time, and the draw ratio in the drawing step are preferably adjusted so that the polarizing element satisfies at least one of the following conditions (i) to (v) in one aspect, (vi It is more preferable to adjust so as to further satisfy the condition of.
(I) for the parallel position _{transmittance,} the absolute value of the difference between the _{AT 420-480} and _{AT 520-590} is 5% or _less, and _{AT _520-590,} the absolute value of the difference between the _{AT 600-640} 3% or less It becomes.
(Ii) With respect to the orthogonal position transmittance, the absolute value of the difference between AT _420-480 and AT _520-590 is 3% or less, and the absolute value of the difference between AT _520-590 and AT _600-640 is 2% or less Become.
(Iii) The single transmittance after the visibility correction is 35% to 50%.
(Iv) Each of the absolute values of the a * value and the b * value is 1.0 or less for the polarizing element alone, and is 2.0 or less for the parallel position.
(V) Each of the absolute values of the a * value and the b * value measured at orthogonal positions is 3 or less.
(Vi) For each of single transmittance and orthogonal transmittance, the difference between the average transmittance of each wavelength of 380 nm to 420 nm and the average transmittance of each wavelength of 420 nm to 480 nm is 15% or less as an independent value. The difference between the average transmittance of each wavelength of 480 nm to 520 nm and the average transmittance of each wavelength of 420 nm to 480 nm is 15% or less as an absolute value, and the average transmittance of each wavelength of 480 nm to 520 nm and each wavelength of 520 nm to 590 nm The difference between the average transmittance and the difference is 15% or less as an absolute value, and / or the difference between the average transmittance of each wavelength of 640 nm to 780 nm and the average transmittance of each wavelength of 600 nm to 640 nm is 20% or less as an absolute value.

(Manufacture of polyvinyl alcohol resin)
The manufacturing method of polyvinyl alcohol-type resin is not specifically limited, A well-known method is employable. The polyvinyl alcohol-based resin can be obtained, for example, by saponifying a polyvinyl acetate-based resin. Examples of polyvinyl acetate resins include polyvinyl acetate which is a homopolymer of vinyl acetate, as well as vinyl acetate and copolymers with other monomers copolymerizable therewith. As another monomer copolymerizable with vinyl acetate, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids etc. are mentioned, for example. The degree of saponification of the polyvinyl alcohol resin is usually about 85 to 100 mol%, preferably 95 mol% or more. This polyvinyl alcohol-based resin may be further modified, and, for example, polyvinyl formal modified with aldehydes, polyvinyl acetal and the like can also be used. Further, the degree of polymerization of the polyvinyl alcohol-based resin means the viscosity average degree of polymerization, and can be determined by a method known in the art. The degree of polymerization is usually about 1,000 to 10,000, preferably about 1,500 to 6,000.

(Production of original film)
Next, a polyvinyl alcohol-based resin is formed into a film to prepare a raw film. The method of forming a polyvinyl alcohol-based resin into a film is not particularly limited, and a known method can be adopted. The raw film may contain glycerin, ethylene glycol, propylene glycol, low molecular weight polyethylene glycol, etc. as a plasticizer. The content of the plasticizer is 5 to 20% by weight, preferably 8 to 15% by weight in the raw film. The thickness of the raw film is not particularly limited, but is preferably about 5 μm to 150 μm, and more preferably about 10 μm to 100 μm.

(Swelling treatment)
The raw film obtained as described above is then subjected to a swelling treatment. The swelling process is carried out by immersing the raw film in a solution at 20 to 50 ° C. for 30 seconds to 10 minutes. The solution is preferably an aqueous solution. The stretching ratio in the swelling treatment is preferably adjusted to 1.00 to 1.50 times, more preferably 1.10 to 1.35 times. In order to swell also in the dyeing | staining process mentioned later, when shortening time to produce a polarizing element, this swelling process may be abbreviate | omitted.

(Staining process)
After the swelling process, a dyeing process is applied. The dyeing process is a process of dyeing using a dye such as an infrared light-absorbing water-soluble compound. Dyes that function as dichroic dyes in the visible region, for example, iodine and iodine compounds, as well as water-soluble compounds that absorb light in at least the infrared region, Non-Patent Document 1, Patent Document 19, Patent Document 20, Patent Document 23, It is a treatment of dyeing using a dye shown in Patent Document 24 or the like, preferably an azo compound described in the formulas (5) to (13). Dyeing is performed, for example, by immersing the film after swelling treatment in a dyeing solution containing the above-mentioned compound. In addition, when using iodine as a dichroic dye, it does not specifically limit as an iodide, For example, potassium iodide, ammonium iodide, cobalt iodide, a zinc iodide etc. are mentioned. The concentration of iodine in the dyeing solution is preferably 0.0001% by weight to 0.5% by weight, more preferably 0.001% by weight to 0.4% by weight, still more preferably 0.001% by weight It is ̃0.1% by weight.

5 to 60 ° C. is preferable, 20 to 50 ° C. is more preferable, and 25 to 50 ° C. is particularly preferable. The time of immersion in the solution can be adjusted appropriately, but it is preferably 30 seconds to 20 minutes, and more preferably 1 to 10 minutes. The staining solution is preferably an aqueous solution. The dyeing method is preferably a method of immersing in a dyeing solution, but a method of applying a dyeing solution to the film after the swelling treatment can also be adopted. The dyeing solution may contain sodium carbonate, sodium hydrogencarbonate, sodium chloride, sodium sulfate, anhydrous sodium sulfate, sodium tripolyphosphate and the like as a dyeing assistant. The content of the dyeing assistant can be optionally adjusted by the time and temperature depending on the dyeability of the dichroic dye, but it is preferably 0 to 5% by weight, more preferably 0.1 to 2% by weight.

When dyeing with a plurality of dyes, the order of the dyeing process is not particularly limited. It may be carried out simultaneously, or the dyes may be impregnated onto the substrate in any order. When other azo compounds are used together with the infrared light-absorbing water-soluble compound, their dyeing is preferably carried out simultaneously. When iodine is used, it is preferable to impregnate the substrate after impregnating the substrate with an infrared light-absorbing water-soluble compound and any other azo compound, from the viewpoint of control of the dyeing solution, productivity and the like.

(First cleaning process)
After the staining process, a washing process (hereinafter, referred to as a "first washing process") can be performed before the next process is performed. The first washing process is a process of washing the dyeing solution attached to the film surface by the dyeing process. By performing the first washing treatment, it is possible to suppress the contamination of the dye in the solution used in the next treatment. In the first cleaning process, water is generally used as the cleaning solution. The washing method is preferably a method of immersing the dyed film in the washing solution, but a method of applying the washing solution to the film after the dyeing treatment can also be adopted. The washing time is not particularly limited, but preferably 1 to 300 seconds, more preferably 1 to 60 seconds. The temperature of the cleaning solution in the first cleaning process needs to be a temperature at which the film after the dyeing process does not dissolve. Generally, it is washed at 5 to 40 ° C. However, even if the first cleaning process is not performed, no problem occurs in the performance, and therefore the first cleaning process may be omitted.

(Treatment to contain crosslinking agent and / or water resistant agent)
After the first washing treatment, a treatment containing a crosslinking agent and / or a water resistant agent can be performed. Examples of the crosslinking agent include boric acid, boron compounds such as borax or ammonium borate, polyaldehydes such as glyoxal or glutaraldehyde, polyisocyanate compounds such as biuret type, isocyanurate type or block type, titanium oxy Examples thereof include titanium-based compounds such as sulfates, ethylene glycol glycidyl ether, polyamide epichlorohydrin and the like. Examples of the water resistant agent include succinic acid peroxy, ammonium persulfate, calcium perchlorate, benzoin ethyl ether, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, ammonium chloride or magnesium chloride and the like. Of these, boric acid is most preferred. The crosslinking agent and the water resistant agent may be used alone or in combination of two or more.

Although the method of immersing the film after the first cleaning treatment in a solution containing a crosslinking agent and / or a water resistance agent is preferred, a solution containing the crosslinking agent and / or a water resistance agent in the film after the first cleaning treatment is preferred. It is also possible to adopt a method of applying The solution is preferably an aqueous solution. The content of the crosslinking agent and / or the water resistance agent in the solution is preferably 0.1 to 6.0% by weight, more preferably 1.0 to 4.0% by weight, taking boric acid as an example. The temperature of the solution is preferably 5 to 70 ° C., more preferably 5 to 50 ° C. The treatment time is preferably 30 seconds to 6 minutes, and more preferably 1 to 5 minutes. However, it is not essential to contain a crosslinking agent and / or a water resistant agent, and in the case where it is desired to shorten the time, this treatment may be omitted when the crosslinking treatment or the water resistance treatment is unnecessary.

(Stretching process)
After the treatment to contain the crosslinking agent and / or the water resistant agent, the stretching treatment is performed. The stretching process is a process of uniaxially stretching a film. The stretching method may be either a wet stretching method or a dry stretching method. The stretching ratio is 3 times or more, preferably 5 to 7 times.

In the case of the wet stretching method, stretching is performed in water, a water-soluble organic solvent, or a mixed solution thereof. The film after the first washing treatment is preferably stretched while being immersed in a solution containing a crosslinking agent and / or a water resistant agent. Examples of the crosslinking agent and the water resistant agent include those described above. The content of the crosslinking agent and / or the water resistance agent in the solution is preferably 0.5 to 15% by weight, more preferably 2.0 to 8.0% by weight, taking boric acid as an example. The stretching ratio is preferably 2 to 8 times, more preferably 5 to 7 times. The temperature of the solution is preferably 40 to 60 ° C., more preferably 45 to 58 ° C. The stretching time is usually 30 seconds to 20 minutes, preferably 2 to 5 minutes. Although the film can be stretched in one step, it can also be carried out by multi-step stretching in two or more steps.

In the case of the dry stretching method, when the stretching heating medium is an air medium, the temperature of the air medium is preferably from normal temperature to 180 ° C. Further, it is preferable to treat in an atmosphere with a humidity of 20 to 95% RH. As a heating method, for example, an inter-roll zone drawing method, a roll heating drawing method, a pressure drawing method, an infrared heating drawing method, etc. may be mentioned, but the drawing method is not limited. Although the film can be stretched in one step, it can also be carried out by multi-step stretching in two or more steps.

(2nd cleaning process)
After the stretching treatment, the cross-linking agent and / or the water-resistant agent may be deposited on the film surface, or foreign matter may adhere to the film surface. Therefore, the film surface is washed (hereinafter referred to as “second washing treatment”). Can do). The washing method is preferably a method of immersing the stretched film in a washing solution, but a method of applying a washing solution to the stretched film can also be adopted. The cleaning process can be performed in one stage, or two or more stages of multistage processes can be performed. The washing time is preferably 1 second to 5 minutes. The temperature of the washing solution is not particularly limited, but is usually 5 to 50 ° C., preferably 10 to 40 ° C.

As the solvent used in the treatment up to here, for example, water, dimethyl sulfoxide, N-methyl pyrrolidone, methanol, ethanol, propanol, isopropyl alcohol, glycerin, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol or Examples thereof include, but are not limited to, alcohols such as trimethylolpropane, amines such as ethylenediamine or diethylenetriamine, and the like. It is also possible to use mixtures of one or more of these solvents. The most preferred solvent is water.

(Drying process)
After the second cleaning process, the film is dried. The drying process can be performed by natural drying. In order to further increase the drying efficiency, the surface may be compressed using a roll, or the surface moisture may be removed by an air knife, a water absorption roll, or the like, or air drying may be performed. The drying temperature is preferably 20 to 100 ° C., and more preferably 60 to 100 ° C. The drying time is preferably 30 seconds to 20 minutes, more preferably 5 to 10 minutes.

By the above method, it is possible to obtain a polarizing element containing an infrared light-absorbing water-soluble compound.

In one aspect, the polarizing element of the present invention contains iodine and has high transmittance, contrast, and durability.

In one aspect, the polarizing element of the present invention has an absolute value of the difference between AT _520-590 and AT _420-480 measured in parallel is 5% or less, and AT _600-640 and AT _520-590. The absolute value of the difference between the light and light is 3% or less, thereby having an achromatic color and high transmittance and polarization degree in the visible region while having absorption or polarization function in the infrared region, and high It is durable.

In one aspect, the polarizing element of the present invention comprises the compound represented by formula (9) or (10), thereby providing high transmittance in the visible region while having absorption or polarization function in the infrared region. Have a high degree of durability.

[Polarizer]
The polarizing plate of the present invention comprises a polarizing element and a transparent protective layer formed on at least one surface of the polarizing element, that is, on one side or both sides. After applying the polymer on at least one surface of the polarizing element, the transparent protective layer can be provided on at least one surface of the polarizing element by drying or heat treatment. Further, a polymer obtained by forming a film into a film is used as a transparent protective layer, and after the transparent protective layer is bonded to at least one surface of the polarizing element, drying or heat treatment is performed to make it transparent to at least one surface of the polarizing element. A protective layer can be provided.

The polymer forming the transparent protective layer is preferably a transparent polymer having high mechanical strength and good thermal stability. As such a polymer, for example, cellulose acetate resin such as triacetyl cellulose and diacetyl cellulose, acrylic resin, polyvinyl chloride resin, nylon resin, polyester resin, polyarylate resin, cyclic polyolefin resin using a cyclic olefin such as norbornene as a monomer And polyethylene, polypropylene, cycloolefin polymer resin, polyolefin having norbornene skeleton or copolymer thereof, and resin having imide group and / or amide group in main chain or side chain. The polymer forming the transparent protective layer may be a liquid crystal polymer. The thickness of the transparent protective layer is, for example, about 0.5 μm to 200 μm. The polarizing plate provided with the transparent protective layer has the same optical characteristics as the polarizing element.

An adhesive is required to bond the transparent protective layer to at least one surface of the polarizing element. Although it does not specifically limit as an adhesive agent, The adhesive agent which has polyvinyl alcohol as a main component is preferable. Examples of the polyvinyl alcohol-based adhesive include, but are not limited to, Gohsenol NH-26 (manufactured by Japan Synthetic Chemical Co., Ltd.), EXEVAL RS-2117 (manufactured by Kuraray Co., Ltd.), and the like. The polyvinyl alcohol-based adhesive can be mixed with a crosslinking agent and / or a water resistant agent. In addition, the polyvinyl alcohol-based adhesive may contain a copolymer of maleic anhydride and isobutylene, or a modified product thereof. Examples of the copolymer of maleic anhydride and isobutylene include Isoban # 18 (manufactured by Kuraray Co., Ltd.) and Isoban # 04 (manufactured by Kuraray Co., Ltd.). Examples of the ammonia-modified maleic anhydride-isobutylene copolymer include isoban. # 104 (made by Kuraray) and isoban # 110 (made by Kuraray) are mentioned, and as the imidized maleic anhydride-isobutylene copolymer, isoban # 304 (made by Kuraray), isoban # 310 (made by Kuraray) Can be mentioned. A water soluble polyfunctional epoxy compound can be used as the crosslinking agent. As a water-soluble polyfunctional epoxy compound, for example, polyglycerol polyglycidyl ether (Denacol EX-521 (manufactured by Nagase Chemtech)), 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane (TETRAD-C) (Mitsubishi Gas Chemical Co., Ltd.)) and the like. Also, known adhesives such as urethane adhesives, acrylic adhesives and epoxy adhesives can be used. In addition, additives such as zinc compounds, chlorides and iodides can be simultaneously contained at a concentration of about 0.1 to 10% by weight for the purpose of improving the adhesive strength of the adhesive or improving the water resistance.

In the case of bonding a polarizing plate to a display device such as liquid crystal or organic electroluminescence, various functional layers for improving the viewing angle and / or contrast and a layer having a luminance improving property are provided on the surface which will later be an unexposed surface. It can be provided. An adhesive is preferably used to bond the polarizing plate to these layers or a display device.

In addition, when the polarizing plate is attached to a display device such as liquid crystal or organic electroluminescence, for example, a known various functional layer such as an antireflection layer, an antiglare layer or a hard coat layer may be provided on the surface to be exposed later. Can. A coating method is preferable for producing the layer having the various functionalities, but a film having the function can be pasted through an adhesive or a pressure-sensitive adhesive. The various functional layers are, for example, layers for controlling the phase difference.

In one aspect, the polarizing plate of the present invention containing iodine has a high degree of polarization around 480 nm and around 600 nm as well as a general iodine-based polarizing plate, and changes color even when applied to a durability test But less than conventional iodine polarizers.

In one embodiment, the substrate comprises a substrate containing an infrared light-absorbing water-soluble compound, and the average value of the transmittance at 520 nm to 590 nm and the transmittance at 420 nm to 480 nm when measured with the absorption axes of two polarizing elements in parallel. The absolute value of the difference between the average and the average ratio is 5% or less, and the absolute value of the difference between the average of the transmittance at 600 nm to 640 nm and the average of the transmittance at 520 nm to 590 nm is 3% or less A polarizing plate using the polarizing element of the present invention characterized in that the achromatic color in the visible region, high transmittance, high degree of polarization and high durability while having absorption or polarization function in the infrared region The dye-based polarizing element can be obtained. In one aspect, a polarizing plate using the polarizing element of the present invention containing the infrared light-absorbing water-soluble compound and the azo compound represented by the formula (9) or the formula (10) has absorption or polarization in the infrared region. While having a function, it is possible to obtain a dye-based polarizing element having high transmittance in the visible region and high degree of polarization. The conventional iodine-based polarizing plate or dye-based polarizing plate can not provide a polarizing element having polarization in the infrared region, and the change in transmittance of 600 nm to 780 nm is extremely large in the durability test, and the polarizing plate is durable It had the problem that it changed in color, for example, turned red after the sex test. That is, there is a problem that the a * value and the b * value in the L * a * b * color system shown in JIS Z 8729 change, and in particular, the absorption axis direction of two polarizing plates In the value of transmittance obtained by measuring in an orthogonal position in an overlapping manner, the increase in transmittance at 600 nm to 780 nm is intense and changes to red, that is, the a * value increases. However, in the method of the present application, a polarizing plate having high durability with less change in such a * value and less color change can be obtained.

The polarizing plate of the present invention may be provided with a support on at least one surface. The support preferably has a flat portion in order to be bonded to the polarizing plate. Examples of the support include molded articles made of an inorganic material such as glass, quartz, sapphire and the like, and organic plastic plates such as acrylic and polycarbonate. For optical applications, the support is preferably a glass molding. As a glass molded article, a glass plate, a lens, a prism (for example, a triangular prism, a cubic prism) etc. are mentioned, for example. Examples of the material of the glass include soda glass and borosilicate glass. What attached the polarizing plate to the lens can be used as a condenser lens with a polarizing plate in a liquid crystal projector. Moreover, what attached the polarizing plate to the prism 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. In addition, the polarizing plate may be attached to the liquid crystal cell. The thickness and size of the support are not particularly limited.

In the polarizing plate provided with glass, in order to further improve the single transmittance, it is preferable to provide an antireflective layer on at least one surface of the glass or the polarizing plate. For example, after a transparent adhesive (adhesive) agent is applied to the flat portion of the support, the polarizing plate of the present invention is attached to the applied surface. In addition, after a transparent adhesive (adhesive) agent is applied to a polarizing plate, a support may be attached to the applied surface. The adhesive (adhesive) agent used here is preferably, for example, an acrylic ester type. In addition, when using this polarizing plate as an elliptically polarizing plate, although it is common to stick a retardation layer to a support body, you may stick a polarizing plate to a support body.

[Liquid crystal display device]
The polarizing element or polarizing plate of the present invention can be used in a liquid crystal display device. A liquid crystal display using the polarizing element or polarizing plate of the present invention becomes a liquid crystal display having high reliability, long-term high contrast, and high color reproducibility.

The polarizing element or polarizing plate of the present invention optionally comprises a protective layer or functional layer, and a support, etc., and is a liquid crystal projector, a calculator, a watch, a notebook computer, a word processor, a liquid crystal television, polarized lenses, polarized glasses, car navigation , Sensors, cameras, analyzers, indoor / outdoor measuring instruments and displays. In particular, it is effectively used in a reflection type liquid crystal display device, a semi-transmission liquid crystal display device, organic electroluminescence and the like.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

<< Example A >>
[Preparation of measurement sample]
Example A1
A polyvinyl alcohol film (VF-PS manufactured by Kuraray Co., Ltd.) having an average degree of polymerization of 99% or more and a degree of polymerization of 2400 was immersed in warm water at 40 ° C. for 2 minutes, and swelling was performed to 1.30 times the draw ratio. . Next, the swelled film is a water-soluble compound that absorbs 1500 parts by weight of water, 1.5 parts by weight of sodium tripolyphosphate, 1.5 parts by weight of anhydrous sodium sulfate, and light in the infrared region of 700 nm to 1400 nm. C. having a structure shown by the formula (101) as I. The film is immersed in an aqueous solution containing 0.30 parts by weight of Direct Black 19 (manufactured by SHAOXING BIYING TEXILE TECHNOLOGY Co., LTD.) And adjusted to 45 ° C. for 3 minutes and 30 seconds, and the above infrared light absorbing water soluble compound is contained in the film. The Next, the obtained film is 28.6 g / l of boric acid (manufactured by Societa chimica lardrello s.p.a), 0.25 g / l of iodine (manufactured by Junsei Chemical Co., Ltd.), potassium iodide (manufactured by Junsei Chemical Co., Ltd.) The film was immersed in an aqueous solution prepared by diluting 100 parts of an aqueous solution adjusted to 17.7 g / l with 2000 parts of water at 30 ° C. for 2 minutes to contain iodine and an iodine compound. Next, the obtained film was subjected to a stretching treatment in an aqueous solution containing 30.0 g / l of boric acid at 50 ° C. for 5 minutes so that the stretching ratio was 5.0 times. Next, while maintaining the tension of the obtained film, immersion treatment was performed at 30 ° C. for 20 seconds in an aqueous solution containing 50 g / l of potassium iodide. Next, the obtained film was dried at 70 ° C. for 9 minutes to obtain a polarizing element. An alkali-treated triacetyl cellulose film (ZRD-60 manufactured by Fuji Film Co., Ltd.) was laminated on the obtained polarizing element using a polyvinyl alcohol adhesive to obtain a polarizing plate. The obtained polarizing plate maintained the optical characteristics of the polarizing element. The durability test sample using the polarizing plate of the present invention is prepared by cutting the polarizing plate into a 40 mm square and bonding to a transparent plate glass through an adhesive layer (AD-ROC manufactured by Polatechno Co., Ltd.), and measurement of the present application It was a sample.

Example A2
C.1 used in Example A1. I. A measurement sample was produced in the same manner as Example A1, except that 0.30 parts by weight of Direct Black 19 was changed to 0.30 parts by weight of S0378 manufactured by FEW CHEMICAL shown in Formula (102).

Example A3
C.1 used in Example A1. I. A measurement sample was produced in the same manner as Example A1, except that 0.30 parts by weight of Direct Black 19 was changed to 0.30 parts by weight of S2180 manufactured by FEW CHEMICAL shown in Formula (103).

Example A4
C.1 used in Example A1. I. A measurement sample was produced in the same manner as Example A1, except that 0.30 parts by weight of Direct Black 19 was changed to 0.30 parts by weight of the compound shown in Compound Example (1-10).

Example A5
C.1 used in Example A1. I. A measurement sample was produced in the same manner as Example A1, except that 0.30 parts by weight of Direct Black 19 was changed to 0.30 parts by weight of the compound shown in the compound example (1-21).

Example A6
C.1 used in Example A1. I. A measurement sample was produced in the same manner as Example A1, except that 0.30 parts by weight of Direct Black 19 was changed to 1.0 part by weight of the compound shown in Compound Example (1-10).

(Comparative Example A1)
In the dyeing step after swelling in Example A1, a C.I. I. An iodine-based polarizing plate containing no azo dye was prepared as a measurement sample in the same manner as Example A1 except that the treatment was not performed with an aqueous solution containing Direct Black 19.

(Comparative Example A2)
C.1 used in Example A1. I. A measurement sample was prepared in the same manner as Example A1, except that 0.30 part by weight of Direct Black 19 was changed to 0.3 part by weight of the azo compound shown in Example 1 of JP-A 3-12606.

[Evaluation method]
The evaluation samples obtained in Examples A1 to A6 and Comparative Examples A1 to A2 were evaluated as follows.

(A) Single transmittance Ts of each wavelength, parallel transmittance Tp of each wavelength, and orthogonal transmittance Tc of each wavelength
Measurement of single transmittance Ts of each wavelength of each measurement sample, parallel transmittance Tp of each wavelength, and orthogonal transmittance Tc of each wavelength using a spectrophotometer (“U-4100” manufactured by Hitachi, Ltd.) did. Here, the single transmittance Ts of each wavelength is the transmittance of each wavelength when measuring one measurement sample. The parallel transmittance Tp of each wavelength is the transmittance of each wavelength measured by overlapping two measurement samples such that the absorption axis directions are parallel to each other. The orthogonal position transmittance Tc of each wavelength is a transmittance of each wavelength obtained by overlapping two measurement samples so that the absorption axis directions are orthogonal to each other. The measurements were made at 5 nm intervals over the wavelength of 400-900 nm.

(B) Single transmittance Ys after correction of visual sensitivity, parallel transmittance Yp after correction of visual sensitivity, and orthogonal transmittance Yc after correction of visual sensitivity
Each optical characteristic (transmittance, polarization degree, hue, etc.) was calculated based on JIS Z 8722: 2009 (C light source 2 ° visual field). By performing visibility correction based on the C light source 2 ° visual field isochromaticity function, the single transmittance Ys after the visibility correction, the parallel transmittance Yp after the visibility correction, and the orthogonal position transmission after the visibility correction The rate Yc was calculated.

(C) Degree of polarization The degree of polarization yy is determined by the following equation (1) from the parallel transmittance Yp after the visibility correction and the orthogonal transmittance Yc after the visibility correction.

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

(D) Chromaticity a * value and b * value For each measurement sample, when measuring single transmittance Ts, measuring parallel transmittance Tp, and measuring orthogonal transmittance Tc according to JIS Z 8781-4: 2013 The chromaticity a * value and b * value in each were measured. The above-mentioned spectrophotometer was used for the measurement, and a C light source was used as a light source. Here, a * -s and b * -s, a * -p and b * -p, and a * -c and b * -c are single transmittance Ts, parallel transmittance Tp, and orthogonal transmittance. These correspond to the chromaticity a * value and the b * value at the time of measurement of the rate Tc.

Single transmittance (Ys-s) after the initial visibility correction of the durability test samples obtained in Examples A1 to 6 and Comparative Examples A1 and A2, and orthogonal transmittance (Yc- after the initial visibility correction) s), initial 780 nm orthogonal transmittance (Tc 780-s), and initial orthogonal a * value (a * c-s), and after application for 1000 hours in a 105 ° C. environment as a durability test Single transmittance after correction of visual sensitivity (Ys-e), orthogonal transmission after correction of visual sensitivity (Yc-e), orthogonal transmission of 780 nm after durability test (Tc 780-e), and durability test The later orthogonal position a * values (a * c-e) are shown in Table A1. As the polarizing element, the value of orthogonal transmittance (Tc 780-e) at 780 nm after the durability test is preferably 35 or less, more preferably 30 or less.

As shown in Table 1, it can be seen that Examples A1 to 6 have comparable transmittance and higher degree of polarization compared to Comparative Examples A1 and 2. Furthermore, even after application at 105 ° C. for 1000 hours, the change in the 780 nm at the orthogonal position is small and the change in the a * value is small as compared with the conventional iodine polarizing plate (comparative example A1). It can be seen that it has high durability with little change in color. That is, the polarizing plate obtained by using the polarizing element of the present invention maintains high durability even in an environment where durability such as high temperature is applied while achieving the same contrast as the conventional iodine-based polarizing plate I understand that I am doing. From the results of the present application, the liquid crystal display device using the polarizing element or polarizing plate of the present invention is not only high brightness and high contrast, but also a highly reliable, long-term high contrast liquid crystal display device.

(E) Degree of Polarization in Near-Infrared Region In Examples A4 to A6, single transmittance (Ts), cross transmittance (Tc), and degree of polarization ()) of 850 nm were measured. The results are shown in Table A2.

As shown in Table 2, it was found that Examples A4 to 6 have a high degree of polarization of 90% or more even at 850 nm which is an infrared region. On the other hand, in Comparative Example A1, the degree of polarization was less than 3%, and almost no polarization performance could be confirmed. That is, the polarizing plate of the present invention not only has a polarization degree as high as that of an iodine-based polarizing plate in the visible range, but also a wide band polarizing plate having a high polarization degree up to the infrared range. I understand that.

<< Example B >>
[Preparation of measurement sample]
Example B1
A polyvinyl alcohol film (VF-PS, manufactured by Kuraray Co., Ltd., VF-PS) having an average degree of polymerization of 99% or more and a degree of polymerization of 99% was immersed in warm water at 40 ° C. for 2 minutes, and swelling treatment was performed to make the draw ratio 1.30 times. Next, as a water-soluble compound capable of absorbing light in the infrared region of 700 nm to 1400 nm, the swelled film is 1500 parts by weight of water, 1.5 parts by weight of sodium tripolyphosphate, 1.5 parts by weight of anhydrous sodium sulfate, And C.I. I. 0.30 parts by weight of Direct Black 19 (manufactured by SHAOXING BIYING TEXITILE TECHNOLOGY Co., LTD.), 0.16 parts by weight of the azo compound shown in the compound example (5-1) of the present invention as a compound of the formula (5) 10) using 0.040 parts by weight of the azo compound represented by the above formula (10-22), and the azo compound represented by the compound example (10-2) of the present invention as a compound having the structure of formula (10) The film was immersed for 13 minutes in an aqueous solution containing 0.16 parts by weight of Kayarus Supra Orange 2GL manufactured by Nippon Kayaku Co., Ltd. and adjusted to 45 ° C. for 13 minutes to contain the above-mentioned infrared light-absorbing water-soluble compound etc. . Next, the obtained film was immersed in an aqueous solution of 40 parts by weight of boric acid (manufactured by Societa Chimica lardrello s.p.a) dissolved in 2000 parts of water at 30 ° C. for 2 minutes. Next, the obtained film was subjected to a stretching treatment in an aqueous solution containing 30.0 g / l of boric acid at 50 ° C. for 5 minutes so that the stretching ratio was 5.0 times. Next, the obtained film was subjected to immersion treatment (washing treatment) in water at 20 ° C. for 20 seconds. Next, the obtained film was dried at 70 ° C. for 9 minutes to obtain a polarizing element. An alkali-treated triacetyl cellulose film (ZRD-60 manufactured by Fuji Film Co., Ltd.) was laminated on the obtained polarizing element using a polyvinyl alcohol adhesive to obtain a polarizing plate. The obtained polarizing plate maintained the optical characteristics of the polarizing element. The durability test sample using the polarizing plate of the present invention is prepared by cutting the polarizing plate into a 40 mm square and bonding to a transparent plate glass through an adhesive layer (AD-ROC manufactured by Polatechno Co., Ltd.), and measurement of the present application It was a sample.

Example B2
C.I. used in Example B1. I. A measurement sample was produced in the same manner as Example B1, except that 0.30 parts by weight of Direct Black 19 was changed to 0.30 parts by weight of S0378 manufactured by FEW CHEMICAL Co., Ltd. shown in the following formula (102).

Example B3
C.I. used in Example B1. I. A measurement sample was produced in the same manner as in Example B1, except that 0.30 parts by weight of Direct Black 19 was changed to 0.30 parts by weight of S2180 manufactured by FEW CHEMICAL Co., Ltd. shown in Formula (103).

Example B4
C.I. used in Example B1. I. A measurement sample was produced in the same manner as Example B1, except that 0.30 parts by weight of Direct Black 19 was changed to 0.30 parts by weight of the compound shown in the present compound example (1-10).

Example B5
C.I. used in Example B1. I. A measurement sample was prepared in the same manner as Example B1, except that 0.30 parts by weight of Direct Black 19 was changed to 0.30 parts by weight of the compound shown in the present compound example (1-21).

Example B6
C.I. used in Example B1. I. A measurement sample was produced in the same manner as Example B1, except that 0.30 parts by weight of Direct Black 19 was changed to 1.0 part by weight of the compound shown in the present compound example (1-10).

Example B7
Measured in the same manner as in Example B6 except that 0.040 parts by weight of the azo compound represented by the formula (10-22) used in Example B6 was changed to 0.3 parts by weight of the azo compound represented by the above formula (11-30) A sample was made.

Example B8
In Example B6, instead of using each of 0.16 parts by weight of the compound shown in the present compound example (5-1) and 0.040 part by weight of the compound shown in the above formula (10-22), C.I. I. Measurement samples were prepared in the same manner as Example B6 except that 0.3 parts by weight of Direct Blue 71 (Compound Example 6-9 of the present invention) was used.

Example B9
In Example B6, instead of using each of 0.16 parts by weight of the compound shown in the present compound example (5-1) and 0.040 part by weight of the compound shown in the above formula (10-22), C.I. I. Measurement samples were prepared in the same manner as in Example B6 except that 0.3 parts by weight of Direct Blue 69 (Compound Example 6-19 of the present application) was used.

Example B10
In Example B6, instead of using 0.16 parts by weight of the compound shown in the present compound example (5-1) and 0.040 parts by weight of the compound shown in the above formula (10-22), instead using the present compound example (6- A measurement sample was produced in the same manner as in Example B6 except that 0.3 part by weight of the azo compound shown in 7) was used and the time for containing the azo compound was changed to 13 minutes to 9 minutes.

Example B11
In Example B10, a measurement sample was produced in the same manner as in Example B10 except that the time for containing the azo compound was changed to 9 minutes to 13 minutes.

Example B12
A compound compound example (10-1) having a structure of the formula (10), C.I. I. A measurement sample was produced in the same manner as Example B6 except that 0.040 parts by weight of Direct Red 81 was used.

Example B13
Except that 0.027 parts by weight of the compound shown in the present compound example (10-2) used in Example B6 was changed to 0.027 parts by weight of the formula (9-23) as an azo compound having a structure of the formula (9) The same test sample as in Example B6 was prepared.

Example B14
0.16 parts by weight of Kayarus Supra Orange 2GL used in Example B6 was isolated from C.I. I. A measurement sample was produced in the same manner as in Example B6 except that 0.16 parts by weight of Direct Orange 72 was used.

Example B15
0.16 parts by weight of Kayarus Supra Orange 2GL used in Example B6 was isolated from C.I. I. A measurement sample was prepared in the same manner as Example B6 except that 0.16 parts by weight of Direct Yellow 28 was used.

(Comparative Example B1)
In Example B1, C.I. I. A measurement sample was prepared in the same manner as Example B1, except that 0.30 parts by weight of Direct Black 19 was not used.

[Evaluation method]
The evaluation samples obtained in Examples B1 to B15 and Comparative Example B1 were evaluated as follows.

(A) Single transmittance Ts, parallel transmittance Tp, and orthogonal transmittance Tc
[Evaluation method] of Example A In the same manner as in (a), the single transmittance Ts, the parallel transmittance Tp, and the orthogonal transmittance Tc of each measurement sample were measured.
Average value of each wavelength at 420 to 480 nm, average value of each wavelength at 520 to 590 nm, and average value of each wavelength at 600 to 640 nm for each of parallel transmittance Tp and orthogonal transmittance Tc, and 800 nm alone The transmittance was determined. The results are shown in Table B1.

(B) Absolute value of difference in average transmittance between two wavelength bands Table B2 shows the average value of each wavelength at 520 to 590 nm and 420 for each of the parallel transmittance Tp and the orthogonal transmittance Tc of each measurement sample. The absolute value of the difference from the average value of each wavelength at ̃480 nm and the absolute value of the difference between the average value of each wavelength at 520-590 nm and the average value of each wavelength at 600-640 nm are shown.

(C) Single transmittance Ys after correction of visual sensitivity, parallel transmittance Yp after correction of visual sensitivity, and orthogonal transmittance Yc after correction of visual sensitivity
The single transmittance Ys after the visibility correction of each measurement sample, the parallel transmittance Yp after the visibility correction, and the orthogonal transmittance Yc after the visibility correction were determined. The single transmittance Ys after the visibility correction, the parallel transmittance Yp after the visibility correction, and the orthogonal transmittance Yc after the visibility correction are predetermined wavelength intervals dλ (here, 5 nm) in the wavelength region of 400 to 700 nm. The transmittance of each of the single wavelength Ts of each wavelength, the parallel transmittance Tp of each wavelength, and the orthogonal transmittance Tc of each wavelength determined according to JIS Z 8722: 2009. is there. Specifically, the single transmittance Ts of each wavelength, the parallel transmittance Tp of each wavelength, and the orthogonal transmittance Tc of each wavelength are substituted into the following formulas (V) to (VII), respectively. did. In the following formulas (V) to (VII), Pλ represents a spectral distribution of standard light (C light source), and yλ represents a two-degree visual field color matching function. The results are shown in Table B3. At this time, a value obtained by dividing Yp by Yc can be expressed as a contrast (CR).

(D) Degree of polarization after visual sensitivity correction The degree of polarization y y after visual sensitivity correction of each measurement sample is expressed by the following formula (from the parallel transmittance Xp after visual sensitivity correction and the orthogonal transmittance Yc after visual sensitivity correction It calculated | required by VIII).

ρy = {(Yp-Yc) / (Yp + Yc)} ^1/2 × 100 (VIII)

(E) Chromaticity a * value and b * value Similar to [Evaluation method] (d) of Example A, a * -s and b * -s, a * -p and b * -p, and a * -C and b * -c were measured.

Table B3 shows Ys, Yp, Yc, CR, ρy, and chromaticity of Examples B1 to B15 and Comparative Example B1.

Table B4 shows the Tp, Tc, and the degree of polarization in the infrared region of 750 nm, 800 nm, and 850 nm of Examples B1 to B15 and Comparative Example B1.

In Table B5, Tp, Tc, and polarization degree at 700 nm which is a wavelength in the visible region and initial polarization plates of Examples B6, B10, and B1 of the initial stage and after applying each polarizing plate at 105 ° C. for 500 hours Indicates each value of.

From the above Tables B1 and B2, although the polarizing element of the present invention is a base material containing a water-soluble compound that absorbs light in the infrared region of 700 nm to 1400 nm, the absorption axes of the two polarizing elements are measured in parallel. The absolute value of the difference between the average value of the transmittance of each wavelength at 520 nm to 590 nm and the average value of the transmittance of each wavelength at 420 nm to 480 nm is 5% or less, and the transmittance of each wavelength at 600 nm to 640 nm It is a polarizing element characterized in that the absolute value of the difference between the average value of the ratio and the average value of the transmittance of each wavelength in 520 nm to 590 nm is 3% or less, or a polarizing plate using the same. I understand. From Table B3, it can be seen that the obtained polarizing element has achromaticity since both a * -s and b * -s are within 1.0 in absolute value. In addition, since both a * -p and b * -p are 2.0 or less in absolute value, it can be understood that the polarizing plate can realize high-quality whiteness at the parallel position. On the other hand, it is understood that the comparative example B1 has a significantly low absorption and polarization degree in the infrared region of 700 nm or more. Table B4 also shows that the polarizing plate of the present invention has a high degree of polarization in the infrared region while realizing an achromatic color. Furthermore, it can be seen from Table B5 that a transmittance of 700 nm, which is a visible region, and a polarizing plate with a small change in polarization degree are obtained.

<< Example C >>
[Preparation of measurement sample]
Example C1
A polyvinyl alcohol film (VF-PS, manufactured by Kuraray Co., Ltd., VF-PS) having an average degree of polymerization of 99% or more and a degree of polymerization of 99% was immersed in warm water at 40 ° C. for 2 minutes, and swelling treatment was performed to make the draw ratio 1.30 times. Next, as a water-soluble compound capable of absorbing light in the infrared region of 700 nm to 1400 nm, the swelled film is 1500 parts by weight of water, 1.5 parts by weight of sodium tripolyphosphate, 1.5 parts by weight of anhydrous sodium sulfate And C.I. I. 0.30 parts by weight of Direct Black 19 (manufactured by SHAOXING BIYING TEXITILE TECHNOLOGY Co., LTD.) As an azo compound having a structure of the formula (9), 0.22 of the azo compound shown in the present compound example (9-23) The present compound example (13-2) as a compound having a structure of formula (13), 0.54 parts by weight of an azo compound represented by the following formula (11-45) as an azo compound having a structure of formula (11) The film was immersed in an aqueous solution containing 0.13 parts by weight of the azo compound shown in and adjusted to 45 ° C. for 13 minutes 00 seconds, and the above-mentioned infrared light-absorbing water-soluble compound and the like were contained in the film. Next, the obtained film was immersed in an aqueous solution of 40 parts by weight of boric acid (manufactured by Societa Chimica lardrello s.p.a) dissolved in 2000 parts of water at 30 ° C. for 2 minutes. Next, the obtained film was subjected to a stretching treatment in an aqueous solution containing 30.0 g / l of boric acid at 50 ° C. for 5 minutes so that the stretching ratio was 5.0 times. Next, the obtained film was subjected to immersion treatment (washing treatment) in water at 20 ° C. for 20 seconds. Next, the obtained film was dried at 70 ° C. for 9 minutes to obtain a polarizing element. An alkali-treated triacetyl cellulose film (ZRD-60 manufactured by Fuji Film Co., Ltd.) was laminated on the obtained polarizing element using a polyvinyl alcohol adhesive to obtain a polarizing plate. The obtained polarizing plate maintained the optical characteristics of the polarizing element. The durability test sample using the polarizing plate of the present invention is prepared by cutting the polarizing plate into a 40 mm square and bonding to a transparent plate glass through an adhesive layer (AD-ROC manufactured by Polatechno Co., Ltd.), and measurement of the present application It was a sample.

Example C2
C.1 used in Example C1. I. A measurement sample was produced in the same manner as Example C1, except that 0.30 parts by weight of Direct Black 19 was changed to S0378 (0.30 parts by weight) manufactured by FEW CHEMICAL Co., Ltd. shown in the following formula (102).

Example C3
C.1 used in Example C1. I. A measurement sample was produced in the same manner as Example C1, except that 0.30 parts by weight of Direct Black 19 was changed to S2180 (0.30 parts by weight) manufactured by FEW CHEMICAL Co., Ltd. shown in Formula (103).

Example C4
C.1 used in Example C1. I. A measurement sample was produced in the same manner as Example C1, except that 0.30 parts by weight of Direct Black 19 was changed to 0.30 parts by weight of the compound shown in Compound Example (1-10).

(Example C5)
A measurement sample is prepared in the same manner as in Example C1 except that 0.30 parts by weight of the infrared light-absorbing water-soluble compound used in Example C1 is replaced with 0.30 parts by weight of the compound shown in Compound Example (1-21). did.

Example C6
C.1 used in Example C1. I. A measurement sample was produced in the same manner as Example C1, except that 0.30 parts by weight of Direct Black 19 was changed to 1.0 part by weight of the compound shown in Compound Example (1-10).

Example C7
Example C6 and Example C6, except that 0.54 parts by weight of the compound shown in the present compound example (11-45) used in Example C6 was replaced with 0.33 parts by weight of the azo compound shown in the present compound example (11-5) Measurement samples were prepared in the same manner.

Example C8
Example C6 and Example C6, except that 0.54 parts by weight of the compound shown in the present compound example (11-45) used in Example C6 was replaced with 0.33 parts by weight of the azo compound shown in the present compound example (12-12) Measurement samples were prepared in the same manner.

Example C9
Example C6 except that 0.54 parts by weight of the compound represented by the present compound example (11-45) used in Example C6 was replaced with 0.46 parts by weight of the azo compound represented by the compound example (11-14) of the present application A measurement sample was prepared in the same manner as in.

Example C10
0.22 parts by weight of a compound shown in the present compound example (9-23) used in Example C6 was treated with C.I. I. A measurement sample was produced in the same manner as Example C6 except that 0.19 parts by weight of DIRECT RED 81 (Compound Example 10-1 of the present application) was used.

Example C11
Example C6 is the same as Example C6 except that 0.22 parts by weight of the compound shown in the present compound example (9-23) of the present application used in Example C6 is replaced with 0.21 part by weight of the azo compound shown in the following formula (10-85). A measurement sample was prepared.

Example C12
Example C6 is the same as Example C6 except that 0.22 parts by weight of the compound shown in the present compound example (9-23) used in Example C6 is replaced with 0.40 parts by weight of the compound shown in the present compound example (10-51) A measurement sample was prepared.

Example C13
In 0.13 parts by weight of a compound shown in the present compound example (13-2) used in Example C6, C.I. I. A measurement sample was produced in the same manner as Example C6 except that 0.11 parts by weight of Direct Orange 72 was used.

Example C14
In 0.13 parts by weight of a compound shown in the present compound example (13-2) used in Example C6, C.I. I. A measurement sample was prepared in the same manner as Example C6 except that 0.16 parts by weight of Direct Yellow 28 was used.

(Comparative Example C1)
In Example C1, C.I. I. A measurement sample was produced in the same manner as Example C1, except that 0.30 parts by weight of Direct Black 19 was not used.

[Evaluation method]
Evaluation of the measurement samples obtained in Examples C1 to C14 and Comparative Example C1 was performed as follows.

(A) Single transmittance Ts of each wavelength, parallel transmittance Tp of each wavelength, and orthogonal transmittance Tc of each wavelength
In the same manner as in [Evaluation method] (a) of Example A, the single transmittance Ts of each wavelength of each measurement sample, the parallel transmittance Tp of each wavelength, and the orthogonal transmittance Tc of each wavelength were measured.

(C) Single transmittance Ys after correction of visual sensitivity, parallel transmittance Yp after correction of visual sensitivity, and orthogonal transmittance Yc after correction of visual sensitivity
Similar to [Evaluation method] (c) of Example B, single transmittance Ys after correction of visibility of each measurement sample, parallel transmittance Yp after correction of visibility, and orthogonal transmittance after correction of visibility We calculated Yc respectively. The results are shown in Table C1. At this time, a value obtained by dividing Yp by Yc can be expressed as a contrast (CR).

(D) Degree of polarization The degree of polarization yy was determined in the same manner as in [Evaluation method] (d) of Example B.

Table C1 shows Ys, Yp, Yc, CR, ρy of Examples C1 to C14 and Comparative Example C1.

Table C2 shows Tp, Tc, and the degree of polarization at near-infrared wavelengths of 750 nm, 800 nm, and 850 nm of Examples C1 to C14 and Comparative Example C1.

Table C3 shows Tp, Tc and polarization degree at 700 nm which is a wavelength in the visible range, and initial values of Example C6 and Comparative Example C1 after application of each polarizing plate at 105 ° C. for 500 hours. .

From Tables C1 and C2, it can be seen that the polarizing element of the present application has a high degree of polarization in the visible region, although it contains a water-soluble compound or a salt thereof that absorbs light in the infrared region of 700 nm to 1400 nm. Further, Table C2 shows that the polarizing element of the present invention not only absorbs light in the infrared region but also has high polarization performance. From this, it can be seen that the polarizing element of the present invention has a high degree of polarization from the visible range to the infrared range. Further, it can be understood from Table C3 that the polarizing plate with a transmittance of 700 nm in the visible region and a polarizing plate with a small change in polarization degree can be obtained, so that the polarizing plate of the present invention has high durability. I understand.

As shown in Tables C1 to C3 described above, the polarizing element or the polarizing plate of the present application has absorption in the infrared region while achieving achromaticity in the visible region, and has a high polarization degree and red. It can be seen that a wide band polarizer having a high degree of polarization up to the outer region is obtained. Moreover, it was shown that the polarizing plate can realize high durability in the visible region.

The polarizing element or polarizing plate of the present invention is a liquid crystal display, organic EL, liquid crystal projector, calculator, watch, notebook computer, word processor, liquid crystal television, polarizing lens, polarizing glasses, car navigation, and indoor / outdoor measuring instruments and displays Optical devices such as infrared sensors, infrared sensors, infrared cameras, optical isolators, and security systems. In particular, it can be effectively used in a reflective liquid crystal display device, a semi-transmissive liquid crystal display device, organic electroluminescence and the like.

Claims

A polarizing element comprising at least one dichroic dye exhibiting polarization characteristics in the visible region, and a water-soluble compound or a salt thereof that absorbs light in the infrared region.
The polarizing element according to claim 1, wherein the water-soluble compound which absorbs light in the infrared region is an azo compound.
The polarizing element according to claim 2, wherein the azo compound is an azo compound represented by the following formula (1):

In the formula, Ai 1 and Ai 2 are each independently represented by a hydrogen atom, an azo group, or the following formula (2) (provided that both Ai 1 and Ai 2 are hydrogen atoms are excluded),
-NH- is bonded to both naphthalene rings at any position of the combination of a and a ', b and b', a and b ', b and a',

In the formula, the rings substituted by Ri 1 are each independently a benzene ring when there is no ring represented by the broken line, and a naphthalene ring when there is a ring represented by the broken line ,
Ri 1 each independently represents a chlorine atom, a sulfo group, a nitro group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms having a sulfo group, An alkyl group having 1 to 4 carbon atoms having a hydroxy group, an alkyl group having 1 to 4 carbon atoms having a carboxy group, an alkoxy group having 1 to 4 carbon atoms having a sulfo group, an alkoxy having 1 to 4 carbon atoms having a hydroxy group A C 1-4 alkoxy group having a group or a carboxy group,
Bi each independently represents a phenyl group which may have a substituent or a naphthyl group which may have a substituent, and the substituent is a hydrogen atom, a chlorine atom, a sulfo group, a nitro group, a hydroxy group, Alkyl group having 1 to 4 carbon atoms, alkoxy group having 1 to 4 carbon atoms, alkyl group having 1 to 4 carbon atoms having a sulfo group, alkyl group having 1 to 4 carbon atoms having a hydroxy group, carbon number having a carboxy group A C 1-4 alkoxy group having a 1-4 alkyl group, a sulfo group, a C 1-4 alkoxy group having a hydroxy group, or an C 1-4 alkoxy group having a carboxy group,
m is an integer of 1 to 3;
When Bi has a hydroxy group as a substituent, the hydroxy group can form —O—Cu—O— with the hydroxy group in the above formula (1) and a copper atom. )
The polarizing element according to any one of claims 1 to 3, wherein the formula (2) is represented by the formula (3):

In the formula, Ri 1 is a substituted ring, Ri 1 and m are respectively the same as in formula (2),
The oxygen atom represented by —O— bond forms —O—Cu—O— with —OH and copper atom in the formula (1),
Ri 2 is a hydrogen atom, a chlorine atom, a sulfo group, a nitro group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms having a sulfo group, hydroxy Alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms having a carboxy group, an alkoxy group having 1 to 4 carbon atoms having a sulfo group, an alkoxy group having 1 to 4 carbon atoms having a hydroxy group Or an alkoxy group having 1 to 4 carbon atoms having a carboxy group.
The polarizing element according to any one of claims 1 to 4, wherein the azo compound represented by the formula (1) is an azo compound represented by the following formula (4):

In the formula, Ri 3 is a hydrogen atom, a chlorine atom, a sulfo group, a nitro group, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms having a sulfo group. Group, an alkyl group having 1 to 4 carbon atoms having a hydroxy group, an alkyl group having 1 to 4 carbon atoms having a carboxy group, an alkoxy group having 1 to 4 carbon atoms having a sulfo group, and 1 to 4 carbon atoms having a hydroxy group Or an alkoxy group having 1 to 4 carbon atoms having a carboxy group,
m is the same as equation (2).
The polarizing element according to any one of claims 1 to 5, wherein the at least one dichroic dye is a compound represented by the formula (5) or the formula (6) or a salt thereof:

In the formula, each of Ab 1 and Ab 2 independently represents a substituted naphthyl group or a substituted phenyl group, and at least one of the substituents is a hydrogen atom, a sulfo group, or an alkyl group having 1 to 4 carbon atoms An alkoxy group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms having a sulfo group, a carboxy group, a nitro group, an amino group, or a substituted amino group,
Rb 1 and Rb 2 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a sulfo group, or an alkoxy group having 1 to 4 carbon atoms having a sulfo group,

In the formula, Ag 1 represents a substituted phenyl group or a substituted naphthyl group,
Bg and Cg are each independently represented by the following formula (7) or the following formula (8), and at least one represents the formula (7),
Xg 1 may have an amino group which may have a substituent, a phenylamino group which may have a substituent, a phenylazo group which may have a substituent, or a substituent Exhibit a good benzoylamino group,

In the formula, Rg 1 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,
k is an integer of 0 to 2;

In the formula, Rg 2 and Rg 3 each 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 having a sulfo group.
The polarized light according to any one of claims 1 to 6, wherein the at least one dichroic dye is a compound represented by the following formula (9) or (10), a metal complex compound thereof, or a salt thereof element:

In the formula, Ac 1 represents a phenyl group or a naphthyl group having at least one substituent selected from the group consisting of a sulfo group and a carboxy group,
Rc 11 to Rc 14 each 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 having a sulfo group,

In the formula, Ac 2 represents a phenyl group or a naphthyl group having at least one substituent selected from the group consisting of a sulfo group and a carboxy group,
Rc 21 to Rc 25 each 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 having a sulfo group,
Rc 26 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms having a sulfo group,
Xc 2 represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a sulfo group, an alkylamino group having 1 to 4 carbon atoms, a hydroxy group, an amino group, a substituted amino group, a carboxy group, and a carboxy An amino group which may have at least one substituent selected from the group consisting of ethylamino groups, a phenylamino group which may have a substituent, a phenylazo group which may have a substituent, a substituent A naphthotriazole group which may have one or more substituents, a benzoyl group which may have one or more substituents, or a benzoylamino group which may have one or more substituents,
p and q each independently represent an integer of 0 or 1.
The at least one dichroic dye is an azo compound represented by the following formula (11), a metal complex compound thereof or a salt thereof, or an azo compound represented by the formula (12) or a salt thereof: The polarizing element according to any one of 7:

In the formula, Ab 1 represents a phenyl group or a naphthyl group having at least one substituent selected from the group consisting of a sulfo group and a carboxy group,
Rb 11 ~ Rb 14 are each independently, represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms having an alkoxy group or a sulfo group having 1-4 carbon atoms, Rb 15 And R b 16 each independently represent an alkoxy group having 1 to 4 carbon atoms,
Xb 1 is composed of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a sulfo group, an amino group, an alkylamino group having 1 to 4 carbon atoms, a hydroxy group, a carboxy group and a carboxyethylamino group An amino group which may have at least one substituent selected from the group, a phenylamino group which may have a substituent, a phenylazo group which may have a substituent, and a substituent A naphthotriazole group, a benzoylamino group which may have a substituent, or a benzoyl group which may have a substituent,
d represents 0 or 1;

In the formula, Ab 2 represents a phenyl group or a naphthyl group having at least one substituent selected from the group consisting of a sulfo group and a carboxy group,
Rb 21 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 2 has 1 to 4 carbon atoms At least one substituent selected from the group consisting of an alkyl group, an alkoxy group having 1 to 4 carbon atoms, an alkylamine group having 1 to 4 carbon atoms, a hydroxy group, a carboxy group, a sulfo group, an amino group and a substituted amino group Amino group which may have, phenylamino group which may have a substituent, phenylazo group which may have a substituent, naphthotriazole group which may have a substituent, even having a substituent Represents a good benzoylamino group or a benzoyl group which may have a substituent.
The polarizing element according to any one of claims 1 to 8, wherein the at least one dichroic dye is an azo compound represented by the following formula (13) or a salt thereof:

In the formula, Ay 1 represents a hydrogen atom, 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,
Each of Ry 1 and Ry 2 independently represents a hydrogen atom, a sulfo group, 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. Represents
h is an integer of 1 to 3.
The polarizing element according to any one of claims 1 to 9, wherein the at least one dichroic dye is iodine.
11. The polarizing element according to any one of claims 1 to 10, wherein the substrate is a polyvinyl alcohol resin film.
The polarizing element according to any one of claims 1 to 11, which has a degree of polarization of 99% or more.
In the transmissivity which is determined in a state in which the two polarizing elements are arranged so that their absorption axes are parallel to each other,
The difference between the average transmittance of each wavelength of 520 nm to 590 nm and the average transmittance of each wavelength of 420 nm to 480 nm is 5% or less as an absolute value, and the average transmittance of each wavelength of 600 nm to 640 nm, 520 nm to 590 nm The difference from the average value of the average transmittance of each wavelength of is 3% or less as an absolute value,
The polarizing element according to any one of claims 1 to 12.
According to JIS Z 8781-4: 2013, the absolute values of a * value and b * value determined at the time of natural light transmittance measurement are
Each of the polarizing elements alone is 1 or less (-1 ≦ a * −s ≦ 1 and −1 ≦ b * −s ≦ 1).
When two polarizing elements are arranged so that their absorption axes are parallel to each other, they are both 2 or less (-2 ≦ a * −p ≦ 2, −2 ≦ b * −p ≦ 2). ,
14. The polarizing element according to any one of claims 1 to 13 (where a * -s represents a single a * value, b * -s represents a single b * value, a * -p represents a parallel) Indicates the a * value in the order, b * -p indicates b * in the parallel order).
In the transmissivity which is determined in a state in which the two polarizing elements are arranged so as to overlap each other so that their absorption axes are orthogonal to each other,
The difference between the average transmittance of each wavelength of 520 nm to 590 nm and the average transmittance of each wavelength of 420 nm to 480 nm is 3% or less as an absolute value, and the average transmittance of each wavelength of 600 nm to 640 nm, 520 nm to 590 nm The difference with the average transmittance of each wavelength of is 2% or less as an absolute value,
The polarizing element according to any one of claims 1 to 14.
A polarizing plate comprising the polarizing element according to any one of claims 1 to 15, and a transparent protective layer on at least one surface of the polarizing element.
An optical device comprising the polarizing element according to any one of claims 1 to 15 or the polarizing plate according to claim 16.
The optical device according to claim 17, which is a liquid crystal display device.