WO2021002440A1

WO2021002440A1 - Highly durable dye-based polarizing plate containing near-infrared absorbing dye

Info

Publication number: WO2021002440A1
Application number: PCT/JP2020/026065
Authority: WO
Inventors: 典明望月; 陵太郎森田; 由侑服部
Original assignee: 日本化薬株式会社
Priority date: 2019-07-03
Filing date: 2020-07-02
Publication date: 2021-01-07
Also published as: JPWO2021002440A1; TW202112979A

Abstract

A polarizing plate which comprises a hydrophilic polymer film containing a near-infrared absorbing dye and a substrate that is provided on one surface or both surfaces of the film, wherein the substrate has at least one of the characteristics (a) and (b) described below.　(a) If the hydrophilic polymer film contains a boron compound, the mass of the boron compound (in terms of boric acid) contained in the hydrophilic polymer film after exposing the polarizing plate to an environment at a relative humidity of 90%RH at 80°C for 1,000 hours is maintained at 20 or more if the mass thereof before exposure is taken as 100. (b) The moisture permeability of the substrate in an environment at a relative humidity of 90%RH at 40°C as determined by a water vapor permeability test in accordance with JIS Z 0208 is from 0 to 1,500 g/m² in 24 hours.

Description

Highly durable dye-based polarizing plate containing near-infrared absorbing dye

The present invention is a dye-based polarizing plate containing a near-infrared absorbing dye, which has high durability in a high temperature and high humidity environment, and particularly high durability even when exposed to strong light in a high temperature and high humidity environment. Regarding the board.

A polarizing plate having a light transmitting / shielding function is used for a display device such as a liquid crystal display (LCD) together with a liquid crystal having a light switching function. The fields of application of this LCD are expanding from small devices such as calculators and watches in the early stages of commercialization to notebook computers, word processors, liquid crystal projectors, liquid crystal televisions, car navigation systems, indoor and outdoor information display devices, measuring devices, and the like. The polarizing plate can also be applied to a lens having a polarizing function, and has been applied to sunglasses with improved visibility, and in recent years, polarized glasses compatible with 3D televisions and the like. In addition to display applications, polarizing plates are also used for the purpose of improving accuracy in authenticity determination devices and improving the signal / noise ratio (S / N ratio) by cutting reflected light in image sensors such as CCD and CMOS. Has been done.

A general polarizing plate is a base material such as a stretch-oriented film of polyvinyl alcohol or a derivative thereof, or a polyene-based film in which polyene is generated and oriented by dehydroxation of a polyvinyl chloride film or dehydration of a polyvinyl alcohol-based film. Is produced by containing iodine or a dichroic dye. Of these, the iodine-based polarizing element has excellent polarization performance, but has low resistance to water and heat, and has a problem in its durability when used for a long time in a high temperature and high humidity state. On the other hand, a dye-based polarizing element using a dichroic dye is superior in moisture resistance and heat resistance to an iodine-based polarizing element, but generally has insufficient polarization performance.

In recent years, not only polarizing plates used in the visible region but also polarizing plates used in the infrared region have been used in applications such as light sources for recognizing operations used for touch panels, security cameras, sensors, anti-counterfeiting devices, and communication devices. Is required. In response to such a request, Patent Document 1 reports an infrared polarizing plate obtained by polyeneizing an iodine-based polarizing plate, and Patent Documents 2 and 3 report an infrared polarizing plate to which a wire grit is applied. Further, Patent Document 4 reports an infrared polarizing element obtained by stretching glass containing fine particles, and Patent Documents 5 and 6 report an infrared polarizing plate using a cholesteric liquid crystal.
However, the infrared polarizing plate of Patent Document 1 has low durability, particularly heat resistance, wet heat durability, and light resistance, and has not been put into practical use. The wire grid type infrared polarizing plates of Patent Documents 2 and 3 can be processed into a film and have high heat resistance, so that they are becoming widespread. However, since this infrared polarizing plate does not maintain its optical characteristics unless the surface has nano-level irregularities, it must not touch the surface and there must be no foreign matter or fine droplets of water on the surface. Limits its use. In addition, it is difficult for this infrared polarizing plate to be anti-reflective or anti-glare. The infrared polarizing plate described in Patent Document 4 has high durability and high dichroism, and has been put into practical use. However, since the glass is stretched while containing fine particles, it is easily broken and brittle. In addition, there is also a problem that it is difficult to process the surface or bond it to another substrate because it does not have the flexibility of a conventional polarizing plate. The infrared polarizing plates described in Patent Documents 5 and 6 are techniques using circularly polarized light, which have been known for a long time, but their colors change depending on the viewing angle. Further, since it is basically a polarizing plate using reflection, stray light is generated and it is difficult to form absolutely polarized light.
As described above, in the absorption type polarizing plate such as the iodine-based polarizing plate, there is no infrared polarizing plate which can be formed into a film, has flexibility, and has high durability. This is because the dyes that have been developed as dichroic dyes have been dyes for the visible region. In response to such a problem, Patent Document 7 discloses that a film containing a dye having absorbency in the infrared region is stretched to obtain a near-infrared polarizing plate. However, this infrared polarizing plate does not deal with the problem that the (near) infrared absorbing dye is inferior in moisture resistance and generates a large amount of heat when absorbing (near) infrared rays. In recent years, even infrared polarizing plates are expected to be applied to in-vehicle devices, so that they have high durability in a high temperature and high humidity environment, especially even when irradiated with infrared rays in a high temperature and high humidity environment. It is starting to be requested. Therefore, an infrared polarizing plate having high durability that can meet such a demand is desired.

U.S. Patent Application Publication No. 2,494,686 Japanese Unexamined Patent Publication No. 2016-148871 Japanese Unexamined Patent Publication No. 2013-24982 Japanese Unexamined Patent Publication No. 2004-86100 International Publication 2015/87709 Japanese Patent No. 5777463 International Publication No. 2018/88558 Japanese Patent No. 5979728 International Release 2010/073649 Japanese Unexamined Patent Publication No. 59-11385 International release 2010/137332 International release 2006/11223

Therefore, an object of the present invention is that a dye-based polarizing plate containing a near-infrared absorbing dye has high durability in a high-temperature and high-humidity environment, and particularly high durability even when exposed to strong light in a high-temperature and high-humidity environment. It is an object of the present invention to provide a polarizing plate having a property.

As a result of diligent research to achieve such an object, the present inventors have obtained a hydrophilic polymer film containing a near-infrared absorbing dye and a substrate provided on one side or both sides of the hydrophilic polymer film. In the dye-based polarizing plate including, the substrate can maintain the amount of the boron compound in the hydrophilic polymer film at a certain level or higher in a high temperature and high humidity environment, and / or in a predetermined moisture permeability test. It has been newly found that a polarizing plate having high durability can be obtained by having a characteristic that the moisture permeability is below a certain level in a high temperature and high humidity environment.

That is, the present invention relates to the following polarizing plate, and an optical device and a display device including the following polarizing plate.
[1] A polarizing plate including a polarizing element made of a hydrophilic polymer film containing a near-infrared absorbing dye and a substrate provided on one side or both sides of the film.
A polarizing plate: the substrate having at least one of the following characteristics a) and b):
a) When the hydrophilic polymer film contains a boron compound, the boron contained in the hydrophilic polymer film after the polarizing plate is exposed to the polarizing plate in an environment of 90% RH and 80 ° C. for 1000 hours. When the mass of the compound is 100 before the exposure, it is maintained at 20 or more.
b) The moisture permeability of the substrate in an environment of 90% RH relative humidity and 40 ° C. based on the JIS Z 0208 moisture permeability test is 0 to 1500 g / m ² in 24 hours.

[2] The polarizing plate according to [1], wherein at least one of the substrates is a resin substrate having the characteristics of b).
[3] The polarizing plate according to [2], wherein substrates are provided on both sides of the hydrophilic polymer film, and an inorganic substrate or a resin substrate having the characteristics of b) is provided on the opposite side of the resin substrate.

[4] The hydrophilic polymer film is composed of a resin selected from the group consisting of polyvinyl alcohol-based resins, amylose-based resins, starch-based resins, cellulosic resins, polyacrylate-based resins, and derivatives thereof. The polarizing plate according to any one of [1] to [3], which contains a boron compound.

[5] The resin substrate contains one or more resins selected from the group consisting of silicon-based resins, (meth) acrylic-based resins, cycloolefin-based resins, polyester-based resins, and polycarbonate resins [2]. The polarizing plate according to any one of [4].

[6] The resin substrate contains a film obtained by polymerizing a polymerizable monomer composition containing a (meth) acrylate compound having three or more (meth) acryloyl groups in the molecule [2] to [5]. ] The polarizing plate according to any one of.
[7] The skeleton according to [6], wherein the (meth) acrylate compound has any skeleton selected from the group consisting of a pentaerythritol skeleton, a neopentyl glycol skeleton, a trimethylolpropane skeleton, and a dicyclopentadiene skeleton. Polarizer.

[8] The polarizing plate according to [6] or [7], wherein the (meth) acrylate compound is contained in an amount of 15% by mass or more based on the solid content concentration of all the monomers of the polymerizable monomer composition.
[9] The polarizing plate according to any one of [3] to [8], wherein the inorganic substrate contains any of glass, quartz, sapphire, crystal, and spinel.
[10] The polarizing plate according to any one of [2] to [9], wherein the thickness of the resin substrate is 0.5 μm to 10 μm.

[11] The polarizing plate according to any one of [4] to [10], wherein the hydrophilic polymer film contains a polyvinyl alcohol resin or a derivative thereof.

[12] The polarizing plate according to any one of [1] to [11], wherein the near-infrared absorbing dye is an azo compound represented by the following formula (1).

(In the formula (1), A ¹ is a phenyl group which may have a substituent, a naphthyl group which may have a substituent or a heterocyclic group which may have a substituent, and A ² ,. A ³ and A ⁴ are independently phenyl groups which may have a substituent or a naphthyl group which may have a substituent, and k represents an integer of 0 or 1. R ¹ represents an integer of 0 or 1. A hydroxy group, an alkoxy group having 1 to 4 carbon atoms or a substituted or unsubstituted amino group, m represents an integer of 0 to 5, M represents a hydrogen, a metal ion or an ammonium ion, and n is 1. of ~ 2 represents an integer. hydrogen atoms of the ring a and ring b are each independently may be substituted with a substituent R ^1, either or both hydrogen atoms of the ring a and ring b is substituted It has been replaced by the group SO ₃ M.)

[13] A ² , A ³ and A ⁴ in the above formula (1) are independently represented by the following formula (2) or formula (3), and at least one of A ² , A ³ and A ⁴ Is the polarizing plate according to [12], which is represented by the formula (2).

In the formula (2), R ² is a carbon substituted with a hydroxy group, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a substituted or unsubstituted amino group or a sulfo group. It represents an alkoxy group of the number 1 to 4, m ² represents an integer of 0 to 6. M represents a hydrogen, metal ion or ammonium ion, and n ³ represents an integer of 0 to 2).

In the formula (3), R ³ and R ⁴ are independently substituted with a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a hydroxy group, respectively. Represents an alkoxy group having 1 to 4 carbon atoms substituted with an alkoxy group of 1 to 4 or a sulfo group.)

[14] The polarizing plate according to [12] or [13], wherein the azo compound of the above formula (1) is a compound represented by the following formula (4).

(In the formula (4), A ¹ , A ² , A ³ , A ⁴ , M, n and k are the same as those in the above formula (1), respectively. Also, one or both hydrogen atoms of the ring a and the ring b are used. Is substituted with the substituent SO ₃ M.)
[15] A ¹ in formula (1) or (4), hydroxy group, one or more substituents selected from the group consisting of alkoxy group and sulfo group having a carbon number of 1 to 4 sulfo groups The polarizing plate according to any one of [12] to [14], which is a naphthyl group substituted with.

In [16] the above formula (1) or (4), ^{A 1} is represented by the following formula (5), [12] The polarizing plate according to any one of - [14].

(In equation (5), n ⁴ represents an integer of 1 to 2.)
[17] Any of [12] to [14], wherein A ¹ in the above formula (1) or (4) is a phenyl group substituted with at least one substituent selected from a nitro group and a sulfo group. The polarizing plate according to.
[18] is a radical selected from the group consisting of groups above formula (1) or the heterocyclic group which may have a substituent at A ¹ in (4) is represented by (6) - (8) , [12] to [14].

(X in formulas (6) to (8) is independently a halogen group, a nitro group, a hydroxy group, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a sulfo group. An aliphatic hydrocarbon group having 1 to 4 carbon atoms substituted with, an aliphatic hydrocarbon group having 1 to 4 carbon atoms substituted with a hydroxy group, and an aliphatic hydrocarbon group having 1 to 4 carbon atoms substituted with a carboxy group. A group, an alkoxy group having 1 to 4 carbon atoms substituted with a sulfo group, an alkoxy group having 1 to 4 carbon atoms substituted with a hydroxy group, or an alkoxy group having 1 to 4 carbon atoms substituted with a carboxy group. q ¹ represents an integer of 0 to 4, q ² represents an integer of 0 to 6. M represents a hydrogen, metal ion, or ammonium ion, and n ¹ and n ² are independent of 0 to 3, respectively. In each formula, * represents the bonding position with the azo bond.)

[19] At least at least 700 to 1500 nm, the ratio of the absorbance of the axis showing the highest transmittance for polarized light to the absorbance of the axis showing the lowest transmittance for polarized light is 5 or more. The polarizing plate according to any one of [1] to [18], which has a certain wavelength range.
[20] The polarizing plate according to any one of [12] to [19], further containing one or more organic dyes other than the azo compound represented by the above formula (1).
[21] The polarizing plate according to [20], which shows neutral gray.

[22] An optical device comprising the polarizing plate according to any one of [1] to [21].
[23] A display device including the polarizing plate according to any one of [1] to [21] or the optical device according to [22].

Despite containing a near-infrared absorbing dye, the above-mentioned polarizing plate and apparatus have high durability even in a high temperature and high humidity environment, and even when exposed to strong light, especially infrared rays, particularly in a high temperature and high humidity environment. Has high durability.

Hereinafter, the present invention will be described in detail according to an embodiment thereof. However, the present invention is not limited to the following embodiments.
The polarizing plate according to the embodiment of the present invention is a dye-based polarizing plate including a hydrophilic polymer film containing a near-infrared absorbing dye and a substrate, wherein the hydrophilic polymer film has a substrate having specific characteristics. By being laminated, it is characterized by having high durability in a high temperature and high humidity environment.
Hereinafter, each component will be described.

(Near infrared absorption dye)
In general, the infrared region (sometimes referred to as an infrared wavelength region or an infrared region wavelength region) refers to a wavelength region of 700 nm to 3000 nm, and a near infrared region refers to a wavelength region of 700 nm to 1500 nm. The polarizing plate according to the embodiment of the present invention contains a near-infrared absorbing dye and exhibits a polarization function in the near-infrared region. Therefore, the polarizing plate according to the embodiment of the present invention has a polarization function in a wavelength region of 700 nm to 1500 nm, but preferably exhibits a polarization function in a wavelength region of 700 nm to 1300 nm, and more preferably in a wavelength region of 750 nm to 1200 nm. Demonstrates the polarization function. The two-color ratio, which is anisotropy of absorption, can be used in a sensor or the like as long as it is 5 or more, but is preferably 10 or more, more preferably 20 or more, still more preferably 30 or more, and particularly preferably 40 or more. Specifically, assuming that the single transmittance is 30%, the polarization degree is 88.2% and the polarization degree is about 90% at the two-color ratio 5, and the polarization degree is 98.3% at the two-color ratio 10. And shows a degree of polarization of about 99%.

Examples of the near-infrared absorbing dye used in the embodiment of the present invention include phthalocyanine type, naphthalocyanine type, metal complex type, boron complex type, cyanine type, squarylium type, diimonium type, diphenylamine / triphenylamine type, and quinone. Examples include system and azo dyes. In general, these dyes extend the absorption wavelength by extending the existing π-conjugated system, and exhibit a wide variety of absorption wavelengths due to their structure. Most of them take the form of hydrophobic dyes and pigments, but some are used as hydrophilic dyes by making them water-soluble. In a preferred embodiment of the present invention, an azo-based near-infrared absorbing dye is used as the near-infrared absorbing dye. In addition, in this specification, a near infrared absorption dye may be simply abbreviated as a dye.

The near-infrared absorbing dye may be in the free form or in the salt form. Therefore, the near-infrared absorbing dyes herein include both forms. Examples of the salt include alkali metal salts such as lithium salt, sodium salt and potassium salt; and organic salts such as ammonium salt and alkylamine salt, and sodium salt is preferable.

General azo dyes absorb light in the visible region, and water-soluble inks are the main use. However, near-infrared absorbing dyes that can absorb up to the near-infrared region by widening the absorption band are commercially available, and these can also be used. For example, Patent Document 8 describes C.I. for the purpose of producing black ink. I. Acid Black 2 (manufactured by Orient Chemical Industry Co., Ltd.), C.I. I. An example of using Direct Black 19 (manufactured by Aldrich Industries, Ltd.) is described, but these dyes can also be used. Further, these azo dyes can be complexed with a metal, and these complexes can also be used. Examples of the complex include compounds of the following formula (9).

In the formula, Mz indicates a central metal, and examples of the metal species include cobalt and nickel. Further, in the formula, Az and Bz each independently represent an aromatic ring such as a phenyl group or a naphthyl group. Specific examples of the dye composed of such a complex include the near-infrared absorber described in Patent Document 10. The contents of Patent Document 10 are incorporated herein by reference.

As the near-infrared absorbing dye, a water-soluble azo compound is preferable, and an azo compound represented by the following formula (1) is particularly preferable.

In the above formula (1), A ¹ is a phenyl group which may have a substituent, a naphthyl group which may have a substituent or a heterocyclic group which may have a substituent, and A ² ,. A ³ and A ⁴ are independently phenyl groups which may have a substituent or a naphthyl group which may have a substituent, and k represents an integer of 0 or 1. R ¹ is a hydrogen atom, a hydroxy group, an alkoxy group having 1 to 4 carbon atoms, or a substituted or unsubstituted amino group, and m represents an integer of 0 to 5. M represents hydrogen, metal ion, or ammonium ion, and n represents an integer of 1 or 2. Hydrogen atoms of the ring a and ring b are each independently may be substituted with a substituent R ^1, either one or both hydrogen atoms of the ring a and ring b is substituted with a substituent SO 3 _M ing.

In A ^1, in the "optionally substituted phenyl group", "optionally substituted naphthyl group" and "optionally substituted heterocyclic group", "substituent" Is not particularly limited, but is, for example, an aliphatic hydrocarbon group having 1 to 4 carbon atoms which may have a substituent, an alkoxy group having 1 to 4 carbon atoms which may have a substituent, and a sulfo group. Substituted alkoxy group having 1 to 4 carbon atoms, aryloxy group which may have a substituent, hydroxy group, sulfo group, carboxy group, nitro group, halogen atom, substituted or unsubstituted amino group, amide group, etc. Can be mentioned.

Examples of the above-mentioned "aliphatic hydrocarbon group having 1 to 4 carbon atoms which may have a substituent" include linear aliphatic carbides such as a methyl group, an ethyl group, an n-propyl group and an n-butyl group. Examples thereof include an aliphatic hydrocarbon group having a branched chain such as a hydrogen group, an isopropyl group, a sec-butyl group and a tert-butyl group, and a cyclic aliphatic hydrocarbon group such as a cyclobutyl group. These substituents include, for example, hydroxy. It may be substituted with a group, a sulfo group, a carboxy group, a substituted or unsubstituted amino group (described later), or an amide group.

Examples of the above-mentioned "alkoxy group having 1 to 4 carbon atoms which may have a substituent" include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an isopropoxy group, a sec-butoxy group and a tert. -Butoxy group, cyclobutoxy group and the like can be mentioned, and these substituents may be substituted with, for example, a hydroxy group, a sulfo group, a carboxy group, a substituted or unsubstituted amino group (described later), or an amide group.

Examples of the above-mentioned "alkoxy group having 1 to 4 carbon atoms substituted with a sulfo group" include a sulfomethoxy group, a sulfoethoxy group, a 3-sulfopropoxy group, a 4-sulfobutoxy group, a 3-sulfobutoxy group and the like. Be done.

Examples of the above-mentioned "aryloxy group which may have a substituent" include 5-membered or 6-membered monocyclic aryloxy or 11- to 14-membered condensed bicyclic aryloxy, and more specifically. Examples include a phenoxy group and a naphthoxy group. The "substituent" in the "aryloxy group which may have a substituent" is not particularly limited, and for example, an aliphatic hydrocarbon group having 1 to 4 carbon atoms which may have the above-mentioned substituent is used. Can be mentioned.

Examples of the above-mentioned "halogen atom" include a chlorine atom and a bromine atom.

Examples of the above-mentioned "substituted or unsubstituted amino group" include an unsubstituted amino group; a mono-C _1-4 alkylamino group such as a methylamino group, an ethylamino group, an n-propylamino group and an n-butylamino group. Monoarylamino groups such as monophenylamino groups and mononaphthylamino groups (5- or 6-membered monocyclic arylamino groups or 11- to 14-membered fused bicyclic arylamino groups), acylamino groups (preferably the formula: Mono-substituted amino groups such as the acylamino group of R-CO-NH- (in the formula, R is an aliphatic hydrocarbon group having 1 to 4 carbon atoms); as well as a dimethylamino group, a diethylamino group, an N-ethyl- DiC _1-4 alkylamino group such as N-methylamino group, diarylamino group such as diphenylamino group (5 or 6 member monocyclic aryl and 11 to 14 member fused bicyclic aryl) selected from 2 Amino group substituted with one aryl), C _1-4 alkyl such as N-ethyl-N-phenylamino group and 5- or 6-membered monocyclic aryl or 11- to 14-membered fused bicyclic aryl Examples thereof include a di-substituted amino group such as an amino group.

The "substituent" of the "phenyl group which may have a substituent" in A ¹ is more preferably a sulfo group, a carboxy group, a hydroxy group, or an alkoxy group having 1 to 4 carbon atoms substituted with a sulfo group. An aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a nitro group, an unsubstituted amino group, an amino group substituted with an aliphatic hydrocarbon having 1 to 4 carbon atoms, the formula. : R-CO-NH-acylamino group (R is an aliphatic hydrocarbon group having 1 to 4 carbon atoms), and formula: C (= O)? NR ₁ R ₂ amide group (in the formula). R is an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and each is independently selected from the group consisting of hydrogen or an aliphatic hydrocarbon group having 1 to 4 carbon atoms). It is a substituent. The "substituent" is more preferably a sulfo group, a carboxy group, a hydroxy group, a chlorine atom, a bromine atom, a nitro group, an unsubstituted amino group, a 3-sulfopropoxy group, a 4-sulfobutoxy group, or a 3-sulfo. It is a butoxy group.

When the phenyl group has two or more substituents, at least one of the substituents is a sulfo group, a nitro group, a carboxy group, or an alkoxy group having 1 to 4 carbon atoms substituted with a sulfo group, and the other Substituents are a sulfo group, a nitro group, an aliphatic hydrocarbon 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 substituted with a sulfo group, a carboxy group, and a halogen. It is preferably an atomic, nitro group, amino group, an amino group substituted with an aliphatic hydrocarbon having 1 to 4 carbon atoms, or an aliphatic hydrocarbon substituted acylamino group having 1 to 4 carbon atoms. Other substituents are more preferably sulfo group, methyl group, ethyl group, methoxy group, ethoxy group, carboxy group, hydroxy group, 2-sulfoethoxy group, 3-sulfopropoxy group, 4-sulfobutoxy group, chlorine. It is an atomic, nitro group, or amino group, more preferably a sulfo group, a carboxy group, a nitro group, a methyl group, a methoxy group, a 2-sulfoethoxy group, a 3-sulfopropoxy group, or a 4-sulfobutoxy group. Particularly preferred are sulfo groups, carboxy groups, nitro groups, methyl groups, methoxy groups, hydroxy groups, 3-sulfopropoxy groups, or 4-sulfobutoxy groups.

The position of the "substituent" of the "phenyl group which may have a substituent" in A ¹ is not particularly limited, but preferably only the 2-position, the 4-position, the 2-position, the 6-position, the 2-position and the 4-position. The ranks, or 3rd and 5th positions are preferable, and only the 2nd place, 4th place only, 2nd and 4th places, or 3rd and 5th places are particularly preferable. Note that only the 2-position and the 4-position mean that only the 2-position or the 4-position has one substituent other than a hydrogen atom.
As a combination of the preferred substituent and its position of the "phenyl group which may have a substituent" in A ^1, phenyl having a sulfo group at the 2-position and a nitro group at the 4-position when the azo bond is at the 1-position. Examples thereof include a group or a phenyl group having a carboxy group at the 3- and 5-positions, respectively.

The "substituent" of the "naphthyl group which may have a substituent" in A ¹ is selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms substituted with a hydroxy group and a sulfo group and a sulfo group. Substituents are preferred, with sulfo groups, 3-sulfopropoxy groups, 4-sulfobutoxy groups or hydroxy groups being even more preferred. When the substitution position of the azo group is set to the 1-position, a naphthyl group in which the 8-position is substituted with a hydroxy group in the counterclockwise direction is more preferable, and further, an arbitrary position is substituted with a sulfo group according to the following formula (5). The naphthyl groups shown are particularly preferred.

(In equation (5), n ⁴ represents an integer of 1 to 2, and 1 is preferable.)

Examples of the "heterocyclic group which may have a substituent" in A ¹ include a thiazole group, an oxazole group, an imidazole group, a thiophene group, a furan group, a pyrrole group and a thiadiazol group which may have a substituent. Examples thereof include a pyrazole group, a pyridyl group, a piperazinyl group, a quinolyl group, a benzoimidazole group, a naphthoimidazole group, a benzothiazole group, a naphthothiazole group, a benzothiasiazol group and the like, and a benzothiazole group or a naphthiazole group which may have a substituent. Groups are preferred.
The "substituent" in the above-mentioned "heterocyclic group which may have a substituent" is not particularly limited, but is preferably a sulfo group, a carboxy group, a halogen atom, a nitro group, a hydroxy group, and 1 to 1 to carbon atoms. An aliphatic hydrocarbon group of 4, an alkoxy group having 1 to 4 carbon atoms, an aliphatic hydrocarbon group having 1 to 4 carbon atoms substituted with a sulfo group, and an aliphatic hydrocarbon having 1 to 4 carbon atoms substituted with a hydroxy group. An aliphatic hydrocarbon group having 1 to 4 carbon atoms substituted with a hydrogen group and a carboxy group, an alkoxy group having 1 to 4 carbon atoms substituted with a sulfo group, and an alkoxy group having 1 to 4 carbon atoms substituted with a hydroxy group. , And an alkoxy group having 1 to 4 carbon atoms substituted with a carboxy group, more preferably a hydroxy group, a carboxy group or a sulfo group.

As such a heterocyclic group, a group selected from the group consisting of the groups represented by the following formulas (6) to (8) is particularly preferable.

(X in formulas (6) to (8) is independently a halogen group, a nitro group, a hydroxy group, a carboxy group, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. , An aliphatic hydrocarbon group having 1 to 4 carbon atoms substituted with a sulfo group, an aliphatic hydrocarbon group having 1 to 4 carbon atoms substituted with a hydroxy group, and a fat having 1 to 4 carbon atoms substituted with a carboxy group. A group hydrocarbon group, an alkoxy group having 1 to 4 carbon atoms substituted with a sulfo group, an alkoxy group having 1 to 4 carbon atoms substituted with a hydroxy group, or an alkoxy group having 1 to 4 carbon atoms substituted with a carboxy group. Yes, preferably a sulfo group, a carboxy group or a hydroxy group, q ¹ represents an integer of 0 to 4, preferably represents 0 or 1, and q ² represents an integer of 0 to 6, preferably 0 or 1. M represents a hydrogen, a metal ion or an ammonium ion, and n ¹ and n ² each independently represent an integer of 0 to 3, preferably 0 or 1. In each formula, * represents. Indicates the bonding position with the azo bond.)

In the above formula (1), A ² , A ³ and A ⁴ are phenyl groups which may have a substituent or naphthyl groups which may have a substituent, respectively. As the "substituent" of "optionally substituted phenyl group" or "an optionally substituted naphthyl group" is not particularly limited, in the A ^1, with a "substituent It may be the same as the substituent exemplified in "Substituent" in "May be a phenyl group", "a naphthyl group which may have a substituent" and "a heterocyclic group which may have a substituent".

In the above formula (1), A ² , A ³ and A ⁴ are independently represented by the following formula (2) or formula (3), and at least one of A ² , A ³ and A ⁴ is It is preferable that it is represented by the formula (2) because a broadband polarizing element can be obtained.

In the above formula (2), R ² is a carbon substituted with a hydroxy group, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a substituted or unsubstituted amino group or a sulfo group. It represents the alkoxy group of the numbers 1 to 4, and m ² represents an integer of 0 to 6. M represents hydrogen, metal ion or ammonium ion, and n ³ represents an integer of 0 to 2. An aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a substituted or unsubstituted amino group, an alkoxy group having 1 to 4 carbon atoms substituted with a sulfo group, and M are each of the formula ( It may be the same as 1).

In the above formula (2), m ² is preferably 0 to 4, more preferably 0 to 2, and particularly preferably 0 or 1. When m ² is 1 or more, R ² is preferably a hydroxy group. n ³ is preferably 0 or 1, more preferably 1. The substitution position of R ^2, when the 1-position the point of attachment to the azo group of A ¹ side in the formula (1), 2, 3, 5-position or 8-position is preferred. Specifically, it is preferable that either the 2-position or the 3-position is substituted with a methoxy group, and it is more preferable that the 3-position is substituted with a methoxy group. Further, the 5-position or 8-position is preferably substituted with a hydroxy group. In the above formula (1), when A ³ or A ⁴ has the structure represented by the above formula (2), it is preferable because it exhibits a polarization function in a wide band and a high degree of polarization, specifically, k = 0. At the time, it is preferable that A ³ has the structure of the formula (2), and when k = 1, it is preferable that A ⁴ has the structure of the formula (2).

In the above formula (3), R ³ and R ⁴ are independently substituted with a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a hydroxy group, respectively. Represents an alkoxy group having 1 to 4 carbon atoms substituted with an alkoxy group of 1 to 4 or a sulfo group. Aliphatic hydrocarbon groups with 1 to 4 carbon atoms, alkoxy groups with 1 to 4 carbon atoms, alkoxy groups with 1 to 4 carbon atoms substituted with hydroxy groups, and alkoxy groups with 1 to 4 carbon atoms substituted with sulfo groups. The groups are the same as in the formula (1), respectively. In the above formula (1), when A ³ or A ⁴ has a structure represented by the formula (3) and R ³ or R ⁴ is independently a hydrogen atom or an alkoxy group having 1 to 4 carbon atoms, it is preferable. Are preferably methoxy groups or ethoxy groups independently, particularly preferably when R ³ and R ⁴ are methoxy groups, because they exhibit a polarization function having a wide band and a high degree of polarization. Specifically, when k = 0, it is preferable that A ³ has the structure of the formula (3) and R ³ and R ⁴ are methoxy groups, and when k = 1, A ⁴ is the formula. It is preferable that it has the structure of (3) and that R ³ and R ⁴ are methoxy groups.

In the above formula (1), R ¹ is a hydrogen atom, a hydroxy group, an alkoxy group having 1 to 4 carbon atoms, or a substituted or unsubstituted amino group. As R ¹ , a hydrogen atom or a hydroxy group is preferable, and a hydroxy group is more preferable. The substitution position of R ¹ is preferably the 5-position when the hydroxy group of the ring a is the 1-position.

In the above formula (1), M represents hydrogen, metal ion or ammonium ion. Examples of the metal ion include alkali metal ions such as lithium ion, sodium and potassium ion, and alkaline earth metal ions such as calcium ion and magnesium ion. Examples of the ammonium ion include ammonium ion, methylammonium ion, dimethylammonium ion, triethylammonium ion, tetraethylammonium ion, tetra-n-propylammonium ion, tetra-n-butylammonium ion, triethanolammonium ion and the like. .. More specifically, for example, when M is hydrogen, it is sulfonic acid (-SO ₃ H), when M is sodium ion, it is sodium sulfonate (-SO ₃ Na), and when M is ammonium ion, it is sulfone. Represents ammonium acid (-SO ₃ NH ₄ ).

The hydrogen atoms of the ring a and the ring b in the above formula (1) may be substituted with the above-mentioned substituent (R ¹ ) and / or the above-mentioned substituent (-SO ₃ M).

It is preferable that one or both of the ring a and the ring b in the above formula (1) are substituted with a sulfo group. It is also preferable that the ring b is substituted with a hydroxy group. Among them, when the azo bond site of the ring a is set to the 1-position, the ring structure in which the 2-position is substituted with a hydroxy group and the 3-position and the 7-position are substituted with a sulfo group counterclockwise, the 4-position is A ring structure substituted with a sulfo group, a ring structure in which the 2-position is substituted with a hydroxy group and the 4-position is substituted with a sulfo group, or a ring structure in which the 7-position is substituted with a sulfo group is particularly preferable.

As the azo compound represented by the above formula (1), a compound represented by the following formula (4) is particularly preferable.

In the above formula (4), A ¹ to A ⁴ , M, n, k, ring a, and ring b are the same as those in the above formula (1), respectively. Among the azo compounds represented by the above formula (1), the compound represented by the above formula (4) is preferable because it exhibits a near-infrared region polarization function having a wider band and a high degree of polarization.

Specific examples of the azo compound represented by the above formula (1) are given below. The sulfo group, carboxy group and hydroxy group in the formula are represented in the form of a free acid, and the azo compound represented by the above formula (1) also includes salts of the compounds listed below.

The azo compound represented by the above formula (1) or a salt thereof can be produced, for example, by performing diazotization and coupling according to a usual method for producing an azo dye as described in Non-Patent Document 1. it can.

As an example of a specific production method, a method for producing a compound with k = 0 in the above formula (1) is described below.

Aminonaphthalene represented by the following formula (A) is diazotized and primary coupled with aminonaphthalene or aniline represented by the following formula (B) to obtain a monoazoamino compound represented by the following formula (C). This monoazoamino compound (C) is diazotized and secondarily coupled with aminonaphthalene or aniline represented by the following formula (D) to obtain a disazoamino compound represented by the following formula (E). The azo compound of the above formula (1) can be obtained by diazotizing the disazoamino compound (E) and performing tertiary coupling with the naphthols of the following formula (F).

In the above production method, the diazotization step is carried out by a normal method of mixing a mineral acid aqueous solution such as hydrochloric acid or sulfuric acid or a turbid solution with a nitrite such as sodium nitrite, or a neutral or weak diazo component. It is preferable to add nitrite to an alkaline aqueous solution and mix it with mineral acid by the reverse method. The temperature of diazotization is preferably −10 to 40 ° C. Further, the coupling with aminonaphthalene or aniline is preferably performed by mixing an acidic aqueous solution such as hydrochloric acid or acetic acid 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 azo compounds of the above formulas (C) and (E) obtained by coupling can be filtered as they are, precipitated by acidification or salting out and filtered out, or as a solution or a turbid solution as follows. You can also proceed to the process. If the diazonium salt is sparingly soluble and is in suspension, it can be filtered and used as a press cake in the next coupling step.

The tertiary coupling reaction between the diazodized diazoamino compound of the above formula (E) and the naphthols represented by the above formula (F) is carried out at a temperature of -10 to 40 ° C. under neutral to alkaline conditions of pH 7 to 10. It is preferable to be carried out in. After completion of the reaction, the obtained azo compound or salt of the formula (1) is preferably precipitated by salting out and filtered out. When purification is required, salting out may be repeated or precipitation may be performed from water using an organic solvent. Examples of the organic solvent used for purification include water-soluble organic solvents such as alcohols such as methanol and ethanol, and ketones such as acetone.

The near-infrared absorbing dye represented by the formula (1) or a salt thereof is useful as a dye for a polarizing element, has a high polarization function in the near-infrared region, and can be combined with other constituent elements described later. It becomes possible to provide a high-performance dye-based near-infrared region polarizing plate having moisture resistance, heat resistance, and light resistance.

(Other organic dyes)
In the embodiment of the present invention, the polarizing element may include, in addition to the near-infrared absorbing dye, another organic dye having polarization performance in the visible region. This makes it possible to realize, for example, a neutral gray dye-based polarizing plate that can control not only the infrared light region but also the visible region. Here, "neutral gray" is a state in which two polarizing elements are superposed so that their orientation directions are orthogonal to each other, and light leakage (color leakage) occurs at a specific wavelength or all wavelengths in the visible region and the near infrared region. ) Means less. In the present specification, other dyes having polarization performance in the visible region may be simply abbreviated as other organic dyes.

The other organic dye is not particularly limited, but is a dye having dichroism in a wavelength region different from the absorption wavelength region of the azo compound represented by the formula (1) or a salt thereof, and the dichroism thereof. Higher dyes are preferred. Examples of such organic dyes include 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 71, 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 81, C.I. I. Direct Red 247, C.I. I. Direct Blue 69, C.I. I. Direct Blue 78, C.I. I. Direct Blue 247, C.I. I. Direct Green 80, and C.I. I. Direct Green 59, etc. are typical examples. These organic dyes can be contained in the polarizing element as free acids or as salts of alkali metal salts (eg Na salt, K salt, Li salt), ammonium salts, or amines.

In the polarizing plate containing other organic dyes together with the near-infrared absorbing dye, the target polarizing plate is included depending on whether it is a neutral gray polarizing plate, a color polarizing plate for a liquid crystal projector, or another color polarizing plate of each color. The types of organic dyes are different. The blending ratio of the other organic dyes is not particularly limited, but when the mass of the near-infrared absorbing dye represented by the formula (1) is 100, the total of one or more other organic dyes. However, it is preferably 0.1 to 10.

In the case of a neutral gray polarizing plate having a polarizing function in the near-infrared region, a near-infrared absorbing dye and other dyes that absorb light in the infrared region so as to reduce color leakage in the visible region of the obtained polarizing plate. It is preferable to adjust the type of organic dye and the blending ratio thereof.

(Hydrophilic polymer film and polarizing element)
In the embodiment of the present invention, the polarizing element contains the above-mentioned near-infrared absorbing dye and optionally another organic dye (hereinafter, may be abbreviated as near-infrared absorbing dye or the like) in an oriented manner. It is composed of a hydrophilic polymer film.

"Hydrophilic polymer film" refers to a film that has a high affinity for water, and usually refers to a film that absorbs and swells water when immersed or in contact with water, which is preferable. It is used to contain or orient a near-infrared absorbing dye or the like. The hydrophilic polymer film is not particularly limited, and examples thereof include a film composed of a polyvinyl alcohol resin, an amylose resin, a starch resin, a cellulose resin, a polyacrylate resin, or a derivative thereof. In the specification of the present application, the “derivative” means a resin having a common basic skeleton peculiar to the above resin, but having some modification added in terms of other structures. Derivatives of the above resins such as polyvinyl alcohol include resins obtained by modifying the above resins with olefins such as ethylene and propylene and unsaturated carboxylic acids such as crotonic acid, acrylic acid, methacrylic acid and maleic acid.
From the viewpoint of adsorptivity and orientation of near-infrared absorbing dyes and the like, a film made of a polyvinyl alcohol resin or a derivative thereof is most preferable.
In order to maintain the oriented state of the near-infrared absorbing dye, etc. even under harsh conditions such as high temperature and high humidity, and to maintain the polarization characteristics, the hydrophilic polymer film must be composed of a resin having a crosslinked structure. Is preferable. Therefore, in a preferred embodiment of the present invention, the polarizing element is composed of a hydrophilic polymer film obtained by cross-linking the resin with a boron compound such as boric acid or borax. Further, a combination of a polarizing element having such a crosslinked structure and a substrate having the characteristics of a) described later is a particularly preferable embodiment of the present invention.
The thickness of the hydrophilic polymer film is not limited, but is usually 10 to 100 μm, preferably about 25 to 80 μm.

In the embodiment of the present invention, the polarizing element contains a near-infrared absorbing dye or the like in a hydrophilic polymer film, and the hydrophilic polymer film is stretched to orient the hydrophilic polymer and the dye contained therein. Therefore, it can be obtained by expressing absorption anisotropy (so-called dichroism) in the near-infrared region and optionally in the visible region.
The hydrophilic polymer film containing a near-infrared absorbing dye or the like is prepared by swelling a hydrophilic polymer film such as a polyvinyl alcohol-based film with warm water or the like, and then adding the near-infrared absorbing dye or the like to 1000 parts by weight of water. On the other hand, it can be produced by immersing the swollen film in an aqueous solution containing 0.001 to 10 parts by mass. The aqueous solution containing a near-infrared absorbing dye or the like may contain a dyeing aid, if necessary, and may contain, for example, Glauber's salt in a concentration of about 0.1 to 10% by mass. The time for immersing the film in the dyeing bath is, for example, about 1 to 10 minutes. The dyeing temperature is preferably about 30 to 80 ° C.

For a hydrophilic polymer film containing a near-infrared absorbing dye or the like, the hydrophilic polymer contains a near-infrared absorbing dye in advance, and the hydrophilic polymer containing the near-infrared absorbing dye is molded into a film. It can also be produced by For example, a near-infrared absorbing dye or the like is contained in an aqueous solution prepared by dissolving polyvinyl alcohol in an amount of 8 to 12% by mass in water at a concentration of 0.01 to 10% by mass in the solid content of the aqueous solution, and the aqueous solution is cast and formed. By evaporating water as a solvent, a hydrophilic polymer film containing a near-infrared absorbing dye or the like can be obtained.

In order to obtain a polarizing element by orienting a near-infrared absorbing dye or the like in a hydrophilic polymer film, a film containing the near-infrared absorbing dye or the like is usually stretched. As a stretching method, for example, a wet method or a dry method is used. Any known method such as a method may be used. When a hydrophilic polymer film containing a near-infrared absorbing dye or the like is stretched by a wet method, for example, it is stretched 2 to 9 times in the uniaxial direction in a tank containing a solution containing a boron compound such as boric acid or borax. Then, by drying, a polarizing element can be obtained.
The treatment with a boron compound is generally performed for the purpose of improving the light transmittance and the degree of polarization of the dye-based polarizing element. However, in the hydrophilic polymer film subjected to such treatment, as will be described later, near Since the infrared absorbing dye can maintain cross-linking with a boron compound such as boric acid or borax in a high temperature and high humidity environment, the boron compound can be used as an index for maintaining the orientation of the near infrared absorbing dye together with the hydrophilic polymer film. The content can be utilized.
The conditions for treating with a boron compound such as boric acid and borax differ depending on the type of hydrophilic polymer film used and the type of near-infrared absorbing dye used. For example, in the case of a film made of polyvinyl alcohol, the boron compound in an aqueous solution The concentration (boric acid conversion value) is in the range of 0.1 to 10% by mass, preferably 0.5 to 7% by mass, and particularly preferably 1 to 5% by mass. The stretching treatment is carried out in a temperature range of, for example, 30 to 80 ° C., preferably 40 to 75 ° C., for example, by immersing for 0.5 to 10 minutes and stretching 2 to 9 times in the uniaxial direction. If the pH of the treatment step is 5 to 9, it is possible to widen the wavelength range having the polarization function of the polarizing element using a near-infrared absorbing dye or the like, but more preferably 6.5 to 8.5. Particularly preferably, 6.0 to 8.0 is mentioned as one preferable form.
As a method for adjusting the pH of the aqueous solution at the time of treatment, particularly the aqueous solution containing boric acid to 6 to 9, it is preferable to add a basic substance such as sodium hydroxide, potassium hydroxide, or borax for treatment. When borax is used, boric acid and borax may be used in combination. If necessary, the fixing treatment may be further carried out with an aqueous solution containing a cationic polymer compound. The stretching treatment may be performed in one stage, or may be performed in two or more stages.

In some cases, the hydrophilic polymer film may be stretched before dyeing. In this case, the orientation of the water-soluble dye is performed at the dyeing stage. The treatment with the boron compound may be performed after the above stretching step. In this case, the stretching step may be carried out in a liquid (for example, water) containing no boron compound.
The performance of the polarizing element can be adjusted by the content of the near-infrared absorbing dye or the like, the dichroism of the near-infrared absorbing dye or the like, the stretching ratio at the time of stretching, or the like.

The stretching treatment may be a dry stretching method. In the dry stretching method, the film is stretched when the film is heated and softened by the heat. In the case of the dry stretching method, stretching is possible using a gas such as air (air) or nitrogen as a stretching heating medium, and the temperature is set in consideration of processability such as the glass transition temperature and melting point of the hydrophilic polymer film. It is preferably stretched at room temperature to 200 ° C. depending on the type of resin constituting the film. Further, the humidity is preferably treated in an arbitrary environment with an atmosphere of 0 to 95% RH. Examples of the heating method include an inter-roll zone stretching method, a roll heating stretching method, a pressure stretching method, an infrared heating stretching method, and the like, but the heating method is limited to these as long as heat is conducted to the film and stretching is possible. It's not something. The draw ratio is preferably 2 to 9 times, but it may be adjusted in consideration of the drawable ratio of each resin and the draw ratio in which the dye can be oriented. The stretching treatment may be performed in one stage, or may be performed in two or more stages.

(substrate)
The polarizing plate includes the above-mentioned polarizing element and a substrate laminated on the polarizing element. In the embodiment of the present invention, the polarizing plate is characterized by comprising a substrate having the following characteristics a) or b), preferably a) and b).
a) When the hydrophilic polymer film contains a boron compound, the mass of the boron compound contained in the hydrophilic polymer film is determined after exposing the polarizing plate in an environment of 90% RH and 80 ° C. for 1000 hours. The pre-exposure is set to 100%, and 20% or more is retained.
b) The moisture permeability in an environment of 90% RH relative humidity and 40 ° C. based on the JIS Z 0208 moisture permeability test of the substrate is 0 to 1500 g / m ² in 24 hours.

Due to the substrate having the above characteristics, the polarizing plate can have high durability even in a high temperature and high humidity environment, and particularly can have high durability even when exposed to strong light in a high temperature and high humidity environment.
That is, in the polarizing plate satisfying the property of a), the content of the boron compound contained in the hydrophilic polymer film is maintained at a high level even when exposed to a high temperature and high humidity environment. This characteristic means that the polarizing element has a high-level crosslinked structure and maintains the orientation state of the near-infrared absorbing dye obtained by stretching. A polarizing plate having such characteristics can suppress isomerization and decomposition deterioration of near-infrared absorbing dyes even in a high-temperature and high-humidity environment, and can maintain high transmittance and high degree of polarization. However, as disclosed in Non-Patent Document 2, not all of the boron compounds are crosslinked in the polarizing element containing the dichroic dye in the hydrophilic polymer film exemplified by polyvinyl alcohol, and further. Boric acid is removed by the crosslinked moisture. In an environment of high temperature and high humidity, the crosslinks of the boron compound are gradually removed from the hydrophilic polymer film and diffused, and the diffusion is not limited to the hydrophilic polymer film, but the adhesive layer laminated on the polarizing element or Move to a transparent protective layer. However, the smaller the migration of the boron compound and the higher the retention rate of the boron compound in the hydrophilic polymer film, the more the cross-linking is maintained, and the higher the level can be retained even when exposed to a high temperature and high humidity environment. Therefore, it is important to prevent the diffusion of the boron compound from the hydrophilic polymer film and the transfer to the substrate, but it is necessary that the boron compound and the substrate have a low affinity. The affinity can be expressed by measuring the solubility and transfer amount of chemical substances, but as a result of our examination, the retention rate of the boron compound in the polarizing element is the index that the transfer of the boron compound is suppressed. It was found to be effective in showing affinity with the substrate. In consideration of the above, it is recommended to use a substrate that retains 20% or more of the mass of the boron compound contained in the hydrophilic polymer film, with 100% before the exposure, even in a high temperature and high humidity environment. The present invention has been reached as an index for giving high durability to a polarizing element containing an absorbing dye or the like.
A polarizing plate satisfying the characteristics of b) means that even if it is exposed to a high temperature and high humidity environment, the amount of water that passes through the substrate and reaches the polarizing element is small. Therefore, the polarizing element is less likely to be relaxed due to moisture, can maintain the orientation state obtained by stretching, and can maintain the molecular cohesive force in the hydrophilic polymer film in a high state. Further, when a boron compound is contained, it indirectly indicates that the cross-linking with the hydrophilic polymer film is hard to be removed, and diffusion and transfer to the substrate are hard to occur. A polarizing plate having such characteristics can suppress isomerization and decomposition deterioration of a near-infrared absorbing dye even in a high-temperature and high-humidity environment, and can maintain high transmittance and high degree of polarization.

Regarding the characteristics of a) above, it is preferable that the amount of the boron compound before the exposure is 100%, and 35% or more of the boron compound is retained after the exposure, and more preferably 50% or more is retained. , 60% or more is more preferable.

Regarding the characteristics of b), the moisture permeability of the substrate when left in an environment of 90% RH and 40 ° C. for 24 hours preferably shows 0 to 1100 g / m ² , and more preferably 0 to 900 g / m. ² shows a, more preferably it is better to indicate the 0 ~ 800g / ^{m 2.}

Any of the above characteristics can be imparted by providing the substrate on one side of the polarizing element, but it is preferable to provide the same or different substrates on both sides of the polarizing element, whereby a high temperature and high humidity environment can be provided from either side of the polarizing element. Even if it is exposed to the bottom, the influence of water and the cross-linking can be broken to suppress the transfer of the boron compound, or both properties can be imparted.
When the substrate is provided on the polarizing element, the substrate may be laminated so as to be in direct contact with the polarizing element, or the substrate may be provided on the polarizing element via another layer such as an adhesive layer. Therefore, in the specification of the present application, when the substrate is provided on "one side or both sides of the polarizing element", the substrate is provided so as to be in direct contact with the polarizing element, and the substrate is provided on the polarizing element via another layer. Includes both.
As another layer, a film generally used as an optical film may be provided between the substrate and the polarizing element. Examples of the optical film that may be provided between the substrate and the polarizing element include a triacetyl cellulose film, a cycloolefin film, an acrylic film, and a film used as a retardation plate, which are generally used for polarizing plates. To. The retardation plate may be a retardation plate made of a polymer or a retardation plate made of a liquid crystal, and is not limited thereto. As the retardation plate, 1 / 4λ, 1 / 2λ, etc. are generally used for the wavelength to be controlled, but any retardation plate may be used.

The substrate that can satisfy the above characteristics a) and / or b) may be an inorganic substrate and an organic resin substrate.

Examples of the inorganic substrate that can satisfy the above-mentioned properties a) and / or b) include a substrate made of transparent glass, quartz, sapphire, crystal or spinel. When the term "transparent" is used in the specification of the present application, it means that the polarizing plate has a transmittance of 20% or more in a wavelength band having polarization characteristics, for example, 380 to 1500 nm. In a polarizing plate that requires transparency, it is more preferable to have a transmittance of 50% or more, further preferably to have a transmittance of 80% or more, and to have a transmittance of 90% or more. Especially preferable. In this respect, a substrate made of quartz, sapphire, or quartz is a highly transparent and preferable inorganic substrate. Further, these inorganic substrates are also preferable in that they have high thermal conductivity, that is, high heat dissipation, and substrates made of sapphire or quartz are more preferable. In a polarizing element in which a near-infrared absorbing dye or the like is oriented in a hydrophilic polymer film, the polarizing element generates heat when it absorbs high-intensity light in the infrared region, so that this type of heat dissipation is high. It has important significance in increasing the durability of the polarizing plate.
Although glass is slightly inferior in terms of transparency, it has an advantage that it can be easily manufactured at low cost, and may be used in combination with other substrates. Glass includes soda glass, borosilicate glass, non-alkali glass and the like, but is not particularly limited.
In the substrate where transparency is not required, another inorganic substrate may be used. For example, it is also possible to obtain a polarized light reflecting element for the purpose of optical polarized light reflection by imparting reflectivity (glossiness) or diffuse reflection on the surface by using aluminum, silver, iron, silicon, copper or the like.
When the substrate is provided on both sides of the polarizing element, it is preferable that at least one of the substrates is an inorganic substrate from the viewpoint of imparting high durability even in a high temperature and high humidity environment, for example, glass, quartz, sapphire or the like. It can be a substrate made of quartz. From the same viewpoint, inorganic substrates may be provided on both sides of the polarizing element. In this case, the substrate may be the same inorganic substrate or a different inorganic substrate. Further, from the viewpoint of transparency and heat dissipation, it is particularly preferable to sandwich both sides of the polarizing element with a substrate made of quartz, sapphire or quartz. When a substrate is provided on one side of the polarizing element and the polarizing plate is attached to an optical device or a display device, if the other surface is attached to an inorganic substrate such as glass of the device, the device is substantially inorganic. The substrate can function as a substrate for the polarizing plate.

When the inorganic substrate is laminated on the polarizing element via the adhesive layer or the adhesive layer, the adhesive or the adhesive is applied to the inorganic substrate to form the adhesive layer or the adhesive layer. The adhesive or the adhesive is not particularly limited as long as it can be adhered, and as the adhesive, for example, an ultraviolet curable adhesive, a heat curable adhesive, a silicon-based adhesive or the like can be used. The pressure-sensitive adhesive is also not particularly limited, and for example, an acrylic (co) polymerized resin obtained by polymerizing a monomer composition containing at least an acrylic acid-based alkyl ester, a silicon-based pressure-sensitive adhesive, or the like can be used. However, it is not limited to these. Further, it may be a combination of a curable adhesive and an adhesive. As the adhesive that combines the curable adhesive and the adhesive, for example, the adhesive blending composition described in Patent Document 9 can be preferably used, and the specification of the present application is referred to by referring to the contents of Patent Document 9. Incorporate into. The adhesive layer may be a resin substrate described later.

As the resin substrate that can satisfy the above characteristics a) or b), one selected from silicon-based resin, acrylic-based resin, olefin-based resin, cycloolefin-based resin, polyester-based resin, vinylidene chloride resin, and polycarbonate resin, Alternatively, a substrate composed of two or more types can be mentioned. In particular, a substrate made of a siloxane silicone resin, an acrylic resin, a cycloolefin resin, a polyester resin, or a polycarbonate resin is preferable. The substrate may be in film shape (thin and flexible).
As the silicone-based resin, for example, a silicone resin polymerized mainly containing an organosilace Kiroxane having a (meth) acryloyl group described in Patent Document 11 (International Publication 2010/137332) is preferable, and a film-forming silicone resin is formed. The resulting film can be used as a substrate. By reference, the contents of Patent Document 11 are incorporated in the specification of the present application.
As the acrylic resin, for example, an acrylic resin is preferable according to the description of Example 1 of Patent Document 12 (International Publication 2006/11223), and a film obtained by forming a film thereof can be used as a substrate. The contents of Document 12 are incorporated herein by reference.
As the film made of the cycloolefin resin, ZEONOR manufactured by Nippon Zeon Corporation and ARTON manufactured by JSR Corporation are exemplified as preferable films, and these films can be used as a substrate.
As the polyester resin, a polyethylene terephthalate resin or a polyethylene naphthalate resin is preferable, and as a film made of these resins, for example, an SRF film manufactured by Toyobo Co., Ltd. is preferable.
As the vinylidene chloride resin, for example, Saran resin manufactured by Asahi Kasei Corporation is preferable, and a film formed by the same can be used as a substrate.
As the polycarbonate resin, Pure Ace manufactured by Teijin Corporation, R film manufactured by Kaneka Corporation, and the like are preferable, and these can be used as a substrate.

The adhesive or adhesive used for laminating the polymer substrate on the polarizing element via the adhesive layer or the adhesive layer is not particularly limited as long as it can be adhered. Examples of the adhesive include an ultraviolet curable adhesive and a heat curable type. Adhesives, silicon-based adhesives and the like can be used. Further, as the pressure-sensitive adhesive, for example, an acrylic (co) polymerized resin obtained by polymerizing a monomer composition containing at least a (meth) acrylic acid-based alkyl ester, a silicon-based pressure-sensitive adhesive, or the like can be used. It is not limited to. Moreover, you may combine the curable adhesive and the pressure-sensitive adhesive. As the adhesive adhesive in which the curable adhesive and the adhesive are combined, the adhesive blending composition described in Patent Document 9 described above can be preferably used. The adhesive layer may be a layer made of a cured product obtained by polymerizing a polymerizable compound described later.

In a preferred embodiment of the present invention, as a resin substrate capable of satisfying the above characteristics a) or b), for example, a compound having a polymerizable substituent such as a glycidyl group, a (meth) acryloyl group, or an isocyanate group is polymerized. Examples thereof include a substrate made of a specific resin.

More specifically, a substrate made of a cured product of the composition containing the polymerizable monomer described in Non-Patent Document 3 can be exemplified, and the contents of Non-Patent Document 3 are incorporated in the present specification by reference. Preferable examples thereof include a substrate made of a cured product obtained by polymerizing a polymerizable monomer composition containing a compound having a (meth) acryloyl group and a polymerization initiator. In a preferred embodiment of the invention, the polymerizable monomer composition comprises a compound having two or more (meth) acryloyl groups. In this embodiment, the polymerizable monomer composition contains a compound having two or more (meth) acryloyl groups in all the monomers, preferably 30% by mass or more, more preferably 50% by mass or more, still more preferably 70% by mass. % Or more.
In a more preferred embodiment of the invention, the polymerizable monomer composition comprises a compound having three or more (meth) acryloyl groups. In this embodiment, the polymerizable monomer composition preferably contains 30% or more, more preferably 50% or more, and 70% or more of the monomers having three or more (meth) acryloyl groups in all the monomers. Is particularly preferable. With a polymerizable monomer composition having such a monomer composition, a substrate made of a resin having a higher hardness and a higher crosslink density can be obtained.

In order for the substrate to satisfy the above-mentioned properties a) and / or b), among the compounds having the (meth) acryloyl group, the pentaerythritol skeleton, the neopentyl glycol skeleton, the trimethylolpropane skeleton, and the dicyclopentadiene skeleton Compounds having at least one or more structures are preferable. In a preferred embodiment, the (meth) acrylate compound having such a skeleton preferably contains 15% by mass or more, more preferably 30% by mass or more, and 50% by mass or more in terms of solid content concentration. It is more preferable, and it is particularly preferable to contain 70% or more.
Examples of compounds having such a structure are shown in Table 1 together with moisture permeability.

The method for evaluating the moisture permeability is a monomer for forming a resin substrate on semi-bleached kraft paper (obtained from Totsuya Echo Co., Ltd.) coated with polyvinyl alcohol having a solid content concentration of 5% to a thickness of 1 μm. The composition is applied and cured to form a resin substrate, or the formed resin substrate or inorganic substrate is attached to the composition. In the composition containing the compound having a (meth) acryloyl group as the polymerizable monomer shown in Table 1 above, 10 parts by weight of the compound having a (meth) acryloyl group, 5 parts by weight of toluene, and 1-hydroxycyclohexylphenylketone (BASF). Irgacure 184) 0.6 parts by weight was mixed to prepare a composition. The composition was coated on the semi-bleached kraft paper anchor-coated with polyvinyl alcohol so that the resin solid content after solvent volatilization had a thickness of 5 μm.
After placing the prepared sample under the condition of b), the moisture permeability of the substrate can be evaluated by confirming the moisture permeability of the semi-bleached kraft paper according to JIS Z 0208.

Examples of products having a pentaerythritol skeleton include KAYARAD PET-30, KAYARAD PET-40, KAYARAD DPHA, etc., examples of products having a neopentyl glycol skeleton include KAYARAD NPGDA, and products having a trimethylolpropane skeleton include KAYARAD TMPTA and the like can be mentioned, and examples of the product having a dicyclopentadiene skeleton include KAYARAD R-684 and the like.
Among such (meth) acrylate compounds, a (meth) acrylate compound having a pentaerythritol skeleton, a neopentyl glycol skeleton, or a trimethylolpropane skeleton is more preferable because of its lower moisture permeability and excellent moisture and heat resistance. A (meth) acrylate compound having an erythritol skeleton is particularly preferred.

When the above resin composition has a composition that is polymerized by ultraviolet rays, the resin composition may contain an ultraviolet polymerization initiator. Examples of the ultraviolet polymerization initiator include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1 (Irgacure 907 manufactured by BASF) and 1-hydroxycyclohexylphenylketone (Irgacure manufactured by BASF). 184), 4- (2-Hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone (Irgacure 2959 manufactured by BASF), 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropane- 1-one (Merck DaroCure 953), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1-one (Merck DaroCure 1116), 2-hydroxy-2-methyl-1-phenylpropane -1-one (Irgacure 1173 manufactured by BASF), acetophenone compounds such as diethoxyacetophenone, benzoin, benzoinmethyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-2-phenylacetophenone Benzophenone compounds such as (Irgacure 651 manufactured by BASF), benzoyl benzoic acid, methyl benzoyl benzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenylsulfide, 3,3'-dimethyl-4. -Benzophenone compounds such as methoxybenzophenone (Kayacure MBP manufactured by Nippon Kayaku), thioxanson, 2-chlorthioxanson (Kayacure CTX manufactured by Nihon Kayaku), 2-methylthioxanson, 2,4-dimethylthioxanson (Japan) Kayakure RTX), Isopropylthioxanson, 2,4-dicloothioxanson (Kayacure CTX made by Nippon Kayaku), 2,4-diethylthioxanson (Kayacure DETX made by Nihon Kayaku), 2,4- Examples thereof include thioxanthone compounds such as diisopropylthioxanson (Kayacure DITX manufactured by Nippon Kayaku). More preferably, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1 (BASF's Irgacure 907), 1-hydroxycyclohexylphenyl ketone (BASF's Irgacure 184), and 2,2-Dimethoxy-2-phenylacetophenone (Irgacure 651 manufactured by BASF) can be mentioned. These photopolymerization initiators may be used alone or in combination in any proportion.

When the above-mentioned benzophenone-based compound or thioxanson-based compound is contained as an ultraviolet polymerization initiator, an auxiliary agent can be used in combination in order to promote the photopolymerization reaction. Such auxiliaries include, for example, triethanolamine, methyldiethanolamine, triisopropanolamine, n-butylamine, N-methyldiethanolamine, diethylaminoethyl methacrylate, Michler ketone, 4,4'-diethylaminophenone, 4-dimethylaminobenzoic acid. Examples thereof include amine compounds such as ethyl acid, 4-dimethylaminobenzoic acid (n butoxy) ethyl, and 4-dimethylaminobenzoate isoamyl.

The amount of the photopolymerization initiator and auxiliary agent added is preferably used within a range in which the polarization performance is not deteriorated, and the amount thereof is a polymerizable substituent such as a (meth) acryloyl group in the polymerizable composition. With respect to 100 parts by weight of the compound, it is preferably 0.5 parts by weight or more and 12 parts by weight or less, and more preferably 2 parts by weight or more and 10 parts by weight or less. The amount of the auxiliary agent is preferably about 0.5 to 2 times the amount of the photopolymerization initiator.

When the above-mentioned polymerizable monomer composition contains a thermally polymerizable monomer, it may contain a polymerization initiator, a cross-linking agent and / or an initiator. As the cross-linking agent, various known cross-linking agents such as isocyanate-based, boron-based, and titanate-based can be used. The amount added is preferably 0.1 part by weight or more and 20 parts by weight or less in 100 parts by weight of the polymerizable monomer composition, and more preferably about 1 part by weight or more and 10 parts by weight or less in 100 parts by weight of the composition.

As a method for forming the resin substrate, for example, the above-mentioned polymerizable monomer composition is diluted as a stock solution or, if necessary, with a solvent and laminated on a polarizing element or a polarizing element, or directly after film formation. Alternatively, the polymerizable resin cured layer of the present invention is coated on a film transferable to a polarizing element via an adhesive layer or the like, and then the solvent is removed by heating or the like as necessary, and the film is heated or irradiated with ultraviolet rays. A substrate can be obtained. A triacetyl cellulose film or the like can be used as the film to be laminated on the polarizing element.

The solvent of the monomer composition preferably has excellent solubility of the monomer in the composition and wettability with respect to the substrate, and does not cause deterioration of the smoothness of the surface of the base material. For example, water; toluene, xylene, etc. Aromatic hydrocarbons; ethers such as anisole, dioxane, tetrahydrofuran; methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 2-pentanone, 3-pentanone, 2-hexanone, 3-hexanone, 2-heptanone, 3 -Ketones such as heptanone, 4-heptanone, 2,6-dimethyl-4-heptanone; alcohols such as n-butanol, 2-butanol, cyclohexanol, isopropyl alcohol; cellosolves such as methyl cellosolve and methyl celloacetate; Esters such as ethyl acetate, butyl acetate, methyl lactate, propylene glycol monomethyl ether acetate, propylene glycol ethyl ether acetate, methoxyethyl acetate, succinate ethoxyethyl; dimethylsulfoxide, acetonitrile, and N, N-dimethylacetoformamide. , Not limited to these. Preferably, it is toluene, cyclopentanone, or ethyl acetate. Further, the solvent may be a single solvent or a mixture. The concentration of the resin composition varies depending on the solvent solubility, the wettability with respect to the substrate, the thickness after coating, and the like, but is preferably about 5 to 95% by weight, more preferably about 10 to 80% by weight.

Further, when the wettability to the substrate is poor or the smoothness of the formed substrate surface is low, it is possible to add various leveling agents to the resin composition in order to improve them. As the leveling agent, various leveling agents such as silicon-based, fluorine-based, polyether-based, acrylic acid copolymer-based, and titanate-based can be used. The amount added is 0.0001 parts by weight or more and 10 parts by weight or less in 100 parts by weight of the polymerizable monomer composition, more preferably 0.1 part by weight or more and 5 parts by weight or less in 100 parts by weight of the monomer composition. Good.

When the film-formed monomer composition is cured, if the adhesion to the polarizing element of the substrate or the film laminated on the polarizing element is poor, various cross-linking agents are added to the monomer composition in order to improve them. It is also possible to do. As the type of cross-linking agent, various compounds such as isocyanate-based, boron-based, and titanate-based compounds can be used. The amount added is 0.0001 parts by weight or more and 20 parts by weight or less in 100 parts by weight of the polymerizable monomer composition, more preferably 0.1 parts by weight or more and 10 parts by weight or less in 100 parts by weight of the composition. ..

As a method of forming the resin substrate, a method of directly coating the polarizing element, a method of providing the resin substrate on the film used for laminating triacetyl cellulose or the like, or a method of forming a layer of the polymerizable monomer composition on another film. A method of providing a substrate on a polarizing element by transfer or lamination, and a method of providing an adhesive layer and laminating a resin substrate on the adhesive layer are also efficient and can easily produce a polarizing plate. The method of applying the polymerizable monomer composition is not particularly limited, and for example, a spin coating method, a wire bar coating method, a gravure coating method, a micro gravure coating method, a calendar coating method, a spray coating method, a meniscus coating method, or the like. Can be mentioned.

In the above resin substrate, it is preferable that the monomers are sufficiently polymerized by heating or irradiation with ultraviolet rays, and the unreacted component is as small as possible. The degree of the unreacted monomer (for example, acrylate compound) in 100 parts by weight of the cured resin composition is 0 parts by weight or more and 5 parts by weight or less, more preferably 0 parts by weight or more and 3 parts by weight or less, still more preferably 0. It is preferable that the weight is equal to or more than 1 part by weight. Examples of the method for obtaining such a layer include a method of optimizing the layer thickness of the resin composition after coating, a method of optimizing the type and amount of the photopolymerization initiator to be added, sufficient heating or ultraviolet rays. There are a method of irradiating with ultraviolet rays, a method of curing by changing the atmosphere at the time of ultraviolet irradiation such as in an inert gas such as nitrogen. As a simple method, the method of optimizing the thickness of the resin layer is convenient in that it can be optimized only by changing the resin concentration or the resin coating amount.

The thickness of the resin substrate is preferably 0.5 μm to 10 μm, more preferably 1 μm to 8 μm, still more preferably 2 μm to 6 μm. If it is thicker than 10 μm, the amount of residual unreacted monomers may increase, resulting in insufficient wet heat durability or reddening of the polarizing plate in the dry heat durability test. On the other hand, if it is thinner than 0.5 μm, the wet and heat durability tends to be insufficient. The irradiation amount of ultraviolet rays varies depending on the type of acrylate compound, the type and amount of photopolymerization initiator added, and the film thickness, but is preferably about 100 to 1500 mJ / cm ² .

Further, it is preferable that the resin substrate is transparent even when treated with an alkaline solution. Specifically, one index is that there is no cloudiness after being treated with an alkaline aqueous solution having a pH of 11 or more at 40 ° C. for 10 minutes or more. As a standard, a film provided with a cured layer obtained by applying an ultraviolet curable monomer composition to a thickness of 5 μm on triacetyl cellulose is treated with an aqueous solution of pH 11 at 40 ° C. for 10 minutes or more, and has a wavelength of 550 nm. The light transmittance in the above is preferably 85% or more, and preferably 90% or more. On the other hand, it is also preferable to make the surface of the resin substrate hydrophilic by treating the resin substrate with an alkaline aqueous solution because the adhesion to a hydrophilic polymer film, for example, a polyvinyl alcohol-based film is improved. As an index of the hydrophilicity of the resin substrate at that time, the contact angle when 10 μliters of water is dropped is preferably 60 ° or less, more preferably 50 ° or less, still more preferably 40 ° or less. .. When bonding to a polarizing element, it is preferable to use a formulation which is treated with an alkaline aqueous solution, neutralized with water or an acidic aqueous solution, and then dried.

When trying to obtain a polarizing plate that satisfies both of the above conditions a) and b), it is preferable to have a multilayer structure having two or more layers of a substrate made of a cured product of the polymerizable monomer composition.

When obtaining a polarizing plate containing the above resin substrate, the resin substrate may be directly laminated on the polarizing element, but for example, a structure of the polarizing plate including a general triacetyl cellulose film (hereinafter abbreviated as TAC). For example, the resin substrate is placed between or on the surface of any one of the polarizing plates having a structure represented by "TAC / adhesive layer (or adhesive layer) / polarizing element / adhesive layer (or adhesive layer) / TAC". Durability can be improved by providing more than one layer. Specifically, on the surface of the TAC that does not face the adhesive layer (or adhesive layer), between the TAC and the adhesive layer (or adhesive layer), or between the adhesive layer (or adhesive layer) and the polarizing element. Durability can be improved by providing one or more layers. In order to further improve the durability, it is effective to provide a resin substrate on the surface side which becomes an exposed surface after being attached to the display device. Specifically, the TAC on the surface side that becomes the exposed surface after the polarizing plate is attached to the display device is attached to TAC (F), and the adhesive layer (or adhesive layer) on the surface side that becomes the exposed surface after being attached to the display device is adhered. When the layer (F) is used, the structure of the polarizing plate is "TAC (F) / adhesive layer (F) / polarizing element / adhesive layer (or adhesive layer) / TAC / adhesive layer / display device". It is preferable to provide a substrate made of a cured polymerizable resin between the surface of the TAC (F), the TAC (F) / the adhesive layer (F), or the adhesive layer (F) / the polarizing element in the configuration. Further, an anchor coat layer may be provided between the polarizing element and the resin substrate in order to improve the adhesion or prevent the migration of unreacted monomers in the resin substrate.

The above-mentioned polarizing element may have a transparent film or layer other than the above-mentioned substrate bonded as a protective layer on one side or both sides thereof. The TAC exemplified in the above-mentioned general polarizing plate configuration can also be one of the protective layers. The transparent protective layer can be provided by forming a layer by coating with a polymer or by laminating films. As the transparent polymer or film forming the transparent protective layer, a transparent polymer or film having high mechanical strength and good thermal stability is preferable. Examples of the substance used as the transparent protective layer include cellulose acetate resins such as triacetyl cellulose and diacetyl cellulose or films thereof, resins or polymers having imide and / or amide main chains or side chains, or films thereof. A liquid crystal resin or a film thereof may be provided. A polarizing plate may be produced by providing one or more layers of the same or different resin or film therein on one side or both sides. The thickness of the protective layer or the film used as the protective layer is not particularly limited, but is preferably 0.5 to 200 μm, preferably 10 to 100 μm.

Examples of the adhesive that can be used to bond the polarizing element and the protective layer include polyvinyl alcohol-based adhesives, urethane emulsion-based adhesives, acrylic adhesives, and adhesives composed of polyol and isocyanate. , Is not particularly limited.

<Surface treatment layer>
A transparent surface treatment layer may be further provided on the surface of the polarizing plate. Examples of the surface treatment layer include an acrylic-based, urethane-based or polysiloxane-based hard coat layer, a general antireflection layer (AR layer), and an antiglare layer (AG layer). Further, in order to further improve the single plate transmittance, it is preferable to provide an AR layer on the protective layer. The AR layer can be formed by depositing or sputtering a substance such as silicon dioxide or titanium oxide, or by applying a thin coating of a fluorine-based substance. The AG layer may be formed by applying a coat layer containing particles made of silica, a polymer, or the like, and exhibiting antiglare properties by internal scattering or scattering forming irregularities. The polarizing plate of the present application can also be used as a circular polarizing plate or an elliptical polarizing plate by further attaching a retardation plate to the surface.

<Use of polarizing plate>
Applications of the polarizing plate obtained in the present invention include, for example, liquid crystal projectors, calculators, clocks, laptop computers, word processors, liquid crystal televisions, car navigation systems, indoor and outdoor measuring instruments and indicators, lenses and glasses, and authenticity determination. Devices, image sensor applications such as CCD and CMOS, etc. The dye-based polarizing element has high polarization performance even in the near infrared region and is also excellent in durability. For this reason, high reliability is required for various liquid crystal displays, liquid crystal projectors, in-vehicle use, and outdoor displays (for example, display applications and wearable applications of industrial instruments) that require high polarization performance and durability. It is particularly suitable for security devices and the like.

Hereinafter, the present invention will be described in more detail by way of examples, but these are exemplary and do not limit the present invention in any way. In addition, "%" and "part" described below are based on mass unless otherwise specified. Further, in each structural formula of the compounds used in each Example and Comparative Example, an acidic functional group such as a sulfo group is described in the form of a free acid, but the present invention is not limited thereto.

[Synthesis Example 1]
(Step 1)
31.9 parts of 4-amino-5-hydroxy-2,7-naphthalene sulfonic acid was added to 200 parts of water, dissolved with 25% sodium hydroxide at pH 6-8, and then 4-toluenesulfonyl. 19.1 parts of chloride was added dropwise while maintaining a pH of 10.5 to 11.0, and the reaction was completed with stirring. Then, it was salted out with sodium chloride and then filtered to obtain 142 parts of a wet cake of the compound represented by the following formula (101).

(Step 2)
142 parts of the obtained wet cake of the compound represented by the formula (101) was added to 300 parts of water, stirred and suspended, the pH was adjusted to 9.0 with 25% sodium hydroxide, and 40% nitrite was added thereto. 15.5 parts of aqueous sodium solution was added. The obtained suspension was added dropwise to a mixed solution of 100 parts of water and 37.5 parts of 35% hydrochloric acid to prepare a diazo solution. On the other hand, 20.1 parts of 8-aminonaphthalene-2-sulfonic acid was added to 200 parts of water and dissolved in a 25% aqueous sodium hydroxide solution while adjusting the pH to 6-8. The previously obtained diazo solution was added dropwise to this solution with 35% hydrochloric acid at a pH of 4.5 to 6.0, and the mixture was stirred to complete the coupling reaction. Then, after salting out with sodium chloride, it was filtered to obtain 148 parts of a wet cake of the monoazo compound represented by the formula (102).

(Step 3)
148 parts of the obtained wet cake of the monoazo compound represented by the formula (102) was added to 300 parts of water, stirred and suspended, and the pH was adjusted to 9.0 using 25% sodium hydroxide, and 40% nitrite was added thereto. 10.9 parts of aqueous sodium solution was added. The obtained suspension was added dropwise to a mixed solution of 100 parts of water and 26.3 parts of 35% hydrochloric acid to prepare a diazo solution. On the other hand, 14.0 parts of 8-aminonaphthalene-2-sulfonic acid was added to 200 parts of water, and a 25% aqueous sodium hydroxide solution was used to dissolve the acid while adjusting the pH to 6-8. The diazo solution of the above formula (102) was added dropwise to this solution with 35% hydrochloric acid at a pH of 4.5 to 6.0, and the mixture was stirred to complete the coupling reaction. Then, after salting out with sodium chloride, the crystals were filtered to obtain 138 parts of a wet cake of the disuazo compound represented by the following formula (103).

138 parts of the obtained wet cake of the disuazo compound represented by the formula (103) was added to 300 parts of water, stirred and suspended, and the pH was adjusted to 9.0 using 25% sodium hydroxide, and 40% nitrite was added thereto. 7.6 parts of aqueous sodium solution was added. The obtained suspension was added dropwise to a mixed solution of 100 parts of water and 18.4 parts of 35% hydrochloric acid to prepare a diazo solution. On the other hand, 14.1 parts of 1,5-dihydroxynaphthalene-2,6-disulfonic acid was added to 150 parts of water and dissolved using a 25% aqueous sodium hydroxide solution while adjusting the pH to 6-8. The diazo solution of the above formula (103) was added dropwise to this solution at a pH of 6.5 to 8.0, and the mixture was stirred to complete the coupling reaction. Then, after salting out with sodium chloride, the crystals were filtered and dried to obtain 74.6 parts of a wet cake of the trisazo compound represented by the following formula (104).

74.6 parts of the obtained wet cake of the trisazo compound represented by the above formula (104) is added to 300 parts of water, stirred and suspended, and pH 10.0 to 10.5 using 25% sodium hydroxide. The mixture was stirred at 50 to 55 ° C. for 2 days. Then, it was salted out with sodium chloride, filtered and dried to obtain 9.0 parts of the water-soluble dichroic dye shown in [Compound Example 1-5] below.

[Synthesis Example 2]
(Step 1)
Add 21.8 parts of 2-amino-5-nitrobenzene sulfonic acid to 500 parts of water and dissolve while adjusting the pH to 6-8 with 25% sodium hydroxide, then add 35% hydrochloric acid to adjust the pH to 0.2. And said. A diazo solution was prepared by adding 17.3 parts of a 40% aqueous sodium nitrite solution to the obtained solution. On the other hand, 22.3 parts of 8-aminonaphthalene-2-sulfonic acid was added to 200 parts of water and dissolved using a 25% aqueous sodium hydroxide solution while adjusting the pH to 6-8. The previously prepared diazo solution was added dropwise to this solution at a pH of 4.5 to 6.0, and the mixture was stirred to complete the coupling reaction. Then, after salting out with sodium chloride, it was filtered to obtain 241 parts of a wet cake of a monoazo compound represented by the following formula (105).

(Step 2)
241 parts of the obtained wet cake of the monoazo compound represented by the above formula (105) was added to 300 parts of water, and the mixture was stirred and suspended. The suspension was adjusted to pH 9.0 with 25% sodium hydroxide, and 34.5 parts of a 40% aqueous sodium nitrite solution was added thereto. The obtained suspension was added dropwise to a mixed solution of 200 parts of water and 50 parts of 35% hydrochloric acid to prepare a diazo solution. On the other hand, 22.3 parts of 8-aminonaphthalene-2-sulfonic acid was added to 200 parts of water and dissolved in a 25% aqueous sodium hydroxide solution while adjusting the pH to 6-8. The diazo solution of the above formula (105) was added dropwise to this solution at a pH of 4.5 to 6.0, and the mixture was stirred to complete the coupling reaction. Then, it was salted out with sodium chloride and then filtered to obtain 342 parts of a wet cake of a disuazo compound represented by the following formula (106).

68.4 parts of the obtained wet cake of the disuazo compound represented by the above formula (106) was added to 400 parts of water, and the mixture was stirred and suspended. The suspension was adjusted to pH 9.0 with 25% sodium hydroxide, and 13.8 parts of a 40% aqueous sodium nitrite solution was added thereto. The obtained suspension was added dropwise to a mixed solution of 100 parts of water and 40 parts of 35% hydrochloric acid to prepare a diazo solution. On the other hand, 4.5 parts of 8-aminonaphthalene-2-sulfonic acid was added to 150 parts of water and dissolved in 25% aqueous sodium hydroxide solution while adjusting the pH to 6-8. The diazo solution of the above formula (106) was added dropwise to this solution with 35% hydrochloric acid at a pH of 4.5 to 6.0, and the mixture was stirred to complete the coupling reaction. Then, it was salted out with sodium chloride and then filtered to obtain 100 parts of a wet cake of a trisazo compound represented by the following formula (107).

50 parts of the obtained wet cake of the trisazo compound represented by the above formula (107) was added to 200 parts of water, and the mixture was stirred and suspended. The suspension was adjusted to pH 9.0 with 25% sodium hydroxide, and 6.9 parts of a 40% aqueous sodium nitrite solution was added thereto. The obtained suspension was added dropwise to a mixed solution of 100 parts of water and 25 parts of 35% hydrochloric acid to prepare a diazo solution. On the other hand, 10.0 parts of 1,5-dihydroxynaphthalene-2,6-disulfonic acid was added to 100 parts of water, and the pH was adjusted to 6 to 8 with a 25% aqueous sodium hydroxide solution and dissolved. The diazo solution of the above formula (107) was added dropwise to this solution with 35% hydrochloric acid at a pH of 6.5 to 8.0, and the mixture was stirred to complete the coupling reaction. Then, it was salted out with sodium chloride, filtered and dried to obtain 5.0 parts of a water-soluble dichroic dye shown in [Compound Example 1-29] below.

<Manufacturing of a polarizing element using [Compound Example 1-5]>
A polyvinyl alcohol film having an average degree of polymerization of 2400 with a saponification degree of 99% or more (VF-PS # 7500 manufactured by Kuraray Co., Ltd.) was immersed in warm water at 45 ° C. for 3 minutes, swelled, and stretched 1.30 times. The swollen film was immersed in a dyeing solution at 45 ° C. containing 1500 parts by mass of water, 1.5 parts by mass of anhydrous Glauber's salt, and 0.30 parts by mass of [Compound Example 1-5] for 15 minutes. The bicolor dye shown in Compound Example 1-5] was contained. The obtained film was immersed in an aqueous solution at 40 ° C. containing 20 g / l of boric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) for 1 minute. The film after immersion was placed in an aqueous solution (pH 5.3) at 50 ° C. containing 30.0 g / l of boric acid, subjected to a stretching treatment for 5 minutes, and stretched 5.0 times. The obtained film was washed by immersing it in water at 25 ° C. for 20 seconds while maintaining its tension. The washed film was dried at 70 ° C. for 9 minutes to obtain a polarizing element.

<Manufacturing of a polarizing element using [Compound Example 1-29]>
A polyvinyl alcohol film having an average degree of polymerization of 2400 with a saponification degree of 99% or more (VF-PS # 7500 manufactured by Kuraray) was immersed in warm water at 45 ° C. for 3 minutes to swell and stretch 1.30 times. The swollen film was immersed in a dyeing solution at 45 ° C. containing 1500 parts by mass of water, 1.5 parts by mass of anhydrous Glauber's salt, and 0.30 parts by mass of [Compound Example 1-29] for 15 minutes. The bicolor dye shown in Compound Example 1-29] was contained. The obtained film was immersed in an aqueous solution at 40 ° C. containing 20 g / l of boric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) for 1 minute. The film after immersion was placed in an aqueous solution (pH 7.0) at 50 ° C. containing 22.0 g / l of boric acid and 8.0 g / l of borax, stretched for 5 minutes, and stretched 5.0 times. The obtained film was washed by immersing it in water at 25 ° C. for 20 seconds while maintaining its tension. The washed film was dried at 70 ° C. for 9 minutes to obtain a polarizing element.

(Measurement of maximum absorption wavelength of polarizing element, its transmittance and degree of polarization)
Regarding the polarizing element manufactured by using the above [Compound Example 1-5] and the polarizing element manufactured by using the above [Compound Example 1-29], the maximum absorption wavelength, the single transmittance (%) of the wavelength, and the single transmittance thereof. The degree of polarization (%) was measured. In the measurement of the maximum absorption wavelength (nm, λmax) of the polarizing element and the calculation of the degree of polarization, the parallel transmittance (Ky,%) and the orthogonal transmittance (Kz,%) at the time of incident polarization are determined by the Gran Thomson polarizing plate (200). Using a spectrophotometer (U-4100 manufactured by Hitachi, Ltd.) provided with a polarizing plate for up to 2600 nm, polarized light was incident on the measurement sample for measurement. Here, the parallel transmittance (Ky) is the transmittance when the absorption axis of the absolute polarizer used at the time of measurement and the absorption axis of the polarizing element are parallel, and the orthogonal transmittance (Kz) is the absolute transmittance used at the time of measurement. The transmittance when the absorption axis of the polarizer and the absorption axis of the polarizing element are orthogonal to each other. The parallel transmittance and the orthogonal transmittance of each wavelength were measured at intervals of 5 nm from 380 to 1200 nm. Using the measured values, the single transmittance of each wavelength is calculated from the following formula (i), the degree of polarization of each wavelength is calculated from the following formula (ii), and the highest degree of polarization at 380 to 1200 nm. , Its maximum absorption wavelength (λmax), and single transmittance were obtained. Further, Ky and Kz were converted into absorbance, and the highest absorbance ratio from the absorbance ratios obtained from them was calculated as the two-color ratio (Rd). In addition, a region having a two-color ratio of 5 or more and a region having a two-color ratio of 10 or more were confirmed.

Table 2 shows the optical characteristics of the wavelength (λmax) having the highest degree of polarization of the obtained polarizing element, and the results of wavelengths in the region where Rd is 5 or more and Rd is 10 or more.

(Equation 1)
Single transmittance (%) = (Ky + Kz) / 2 (i)
(Equation 2)
Polarization degree (%) = [(Ky-Kz) / (Ky + Kz)] x 100 (ii)

As shown in Table 1, the polarizing element manufactured by using the above [Compound Example 1-5] and the polarizing element manufactured by using the above [Compound Example 1-29] have high polarization performance at the maximum absorption wavelength (λmax). All had absorption anisotropy of a two-color ratio (Rd) of 5 or more in the near infrared region. Further, a band having a two-color ratio of 10 or more exists at 1080 nm, and the polarizing element has a high degree of polarization in a wide band region.

<Making a double-sided adhesive sheet>
According to the formulation of Example 1 of Patent Document 9, a double-sided adhesive sheet for adhering the substrate and the polarizing element was obtained. The contents of Patent Document 9 are incorporated herein by reference.
Specifically, 94 g of n-butyl acrylate, 1 g of 2-hydroxyethyl acrylate, and 5 g of N, N-dimethylacrylamide were dissolved in 185 g of ethyl acetate, and 0.05 g of azobisisobutyronitrile was added to 70. Polymerization at ° C. for 5 hours gave an acrylic resin copolymer solution. The obtained acrylic copolymer had a weight average molecular weight of 1,100,000 by gel permeation chromatography (GPC) in terms of polystyrene. Next, ethyl acetate was added to the obtained copolymer solution to adjust the resin content to 22.5% by weight to obtain an acrylic pressure-sensitive adhesive. The obtained acrylic pressure-sensitive adhesive having a resin content of 22.5% by weight was added to a solid content of 79 parts by weight, an isocyanate-based cross-linking agent (Coronate RTMHL manufactured by Toso Corporation) by 0.035 parts by weight, and 3-glycidoxypropyltri. Methoxysilane (KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.) 0.009 parts by weight, dibutyltin dilaurate (manufactured by Genuine Chemical Co., Ltd.) 0.002 parts by weight, 3-acryloxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.) as an alkoxysilane having an acrylic group KBM-5103) 17 parts by weight, KAYARAD R-115 (manufactured by Nippon Kayaku Co., Ltd.) as a bifunctional photopolymerizable compound, 2 parts by weight, Irgacure-184 (manufactured by BASF) as a photopolymerization initiator 2 parts by weight and 32 parts by weight of 2-butanone were mixed to obtain a compounding composition used in the present invention. Methyl ethyl ketone was added so that the solid content of the obtained compounding composition was 20 parts by weight, and the mixture was mixed for 1 hour to obtain the compounding composition of the present invention for an adhesive sheet. Using a coating machine, the obtained compounding composition was sandwiched between two release films (polyethylene terephthalate film) and molded into a sheet shape. The obtained sheet had a thickness of 20 μm and was used as a double-sided adhesive sheet for a laminate.

<Effect on the retention of boron compounds in the hydrophilic polymer film of the substrate>
(1) Substrate to be tested
Resin substrate-1
10 parts by weight of PET-30 (pentaerythritol triacrylate) manufactured by Nippon Kayaku Co., Ltd., 5 parts by weight of toluene, and 0.6 parts by weight of 1-hydroxycyclohexylphenyl ketone (Irgacure 184 manufactured by BASF) are mixed and irradiated with ultraviolet rays. Formed.
Resin substrate-2
5 parts by weight of PET-30 (pentaerythritol triacrylate) manufactured by Nippon Kayaku Co., Ltd., 5 parts by weight of FA-511A (dicyclopentenyl acrylate) manufactured by Hitachi Kasei, 5 parts by weight of toluene, and 1-hydroxycyclohexylphenylketone (manufactured by BASF). Irgacure 184) 0.6 parts by weight was mixed and formed by irradiating with ultraviolet rays.
Resin substrate-3
10 parts by weight of PEG-400DA (polyethylene glycol diacrylate) manufactured by Nippon Kayaku Co., Ltd., 5 parts by weight of toluene, and 0.6 parts by weight of 1-hydroxycyclohexylphenyl ketone (Irgacure 184 manufactured by BASF) are mixed and irradiated with ultraviolet rays. Formed.
Resin substrate-4
A cycloolefin film (trade name: Zeonor) manufactured by Zeon Corporation was used.
Resin substrate-5
It was prepared by forming an acrylic resin into a film of 40 μm according to the description of Example 1 of the internationally published patent WO2006-112223 .
Inorganic substrate-1
A white transparent plate glass substrate manufactured by Kuzo Kawamura was used.
Inorganic substrate-2
A crystal substrate manufactured by Iwate Murata Manufacturing Co., Ltd. was used.
As a comparison of TAC films, TAC film (TD-80U manufactured by Fuji Film Co., Ltd.) was used as a test target.

(2) Preparation of measurement sample A polyvinyl alcohol film (VF-PS # 7500 manufactured by Kuraray Co., Ltd.) having an average degree of polymerization of 2400 with a saponification degree of 99% or more, which is a hydrophilic polymer film, is immersed in warm water at 45 ° C. for 3 minutes. , Swelled and stretched 1.30 times. The swollen film was immersed in warm water at 45 ° C. for 15 minutes, and the obtained film was immersed in an aqueous solution at 40 ° C. containing 20 g / l of boric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) for 1 minute. The film after immersion was stretched 5.0 times in an aqueous solution at 50 ° C. containing 30.0 g / l of boric acid for 5 minutes. The obtained film was washed by immersing it in water at 25 ° C. for 20 seconds while maintaining its tension. The washed film was dried at 70 ° C. for 9 minutes to obtain a polyvinyl alcohol film containing a boron compound. A triacetyl cellulose film obtained by dissolving the obtained polyvinyl alcohol film containing a boron compound in water at 4% of polyvinyl alcohol (NH-26 manufactured by Nippon Vinegar Bi-Poval Co., Ltd.) as an adhesive and treating it with an alkali. (TD-80 manufactured by Fuji Film Co., Ltd., hereinafter abbreviated as TAC film) is laminated on one side, and each substrate is further laminated on the other side via the above-mentioned double-sided adhesive sheet, and the substrate / double-sided adhesive sheet. A measurement sample was prepared with the composition of / polyvinyl alcohol film containing a boron compound / PVA adhesive layer / TAC film / double-sided adhesive sheet / glass.

(3) Test method After placing the obtained measurement sample in an environment of 80 ° C. and 90% RH for 1000 hours, only the polyvinyl alcohol film containing the boron compound was taken out, and the amount of the boron compound remaining on the polyvinyl alcohol film was taken out. Was measured.
Regarding the content of the boron compound, first, about 0.05 g of a polyvinyl alcohol film containing a boron compound is dissolved in 50 g of water and boiled for 60 minutes to dissolve or completely swell the polyvinyl alcohol film and cool to room temperature. -)-Add 3 g of mannitol, add 0.05 mol / l sodium hydroxide aqueous solution until pH = 8.4, and determine the boric acid concentration based on the added amount to determine the content of the boron compound. .. The content of the boron compound is determined by the formula (iii). At this time, B indicates the dropping amount (ml) at which pH = 8.4 when sodium hydroxide is dropped only with water. F indicates the factor of the aqueous sodium hydroxide solution.

(Equation 3)
Boron compound content (%) = (Titration of sodium hydroxide [ml] -B) x F x 0.30915 / Weight of polarized light emitting device [g] (iii)

Table 3 below shows the test results of each substrate used for measuring the moisture permeability and the retention rate of the boron compound.

As described above, it can be seen that the resin substrate-3 and the TAC film do not satisfy the condition a) above.

<Measurement of moisture permeability>
(1) Preparation of measurement sample having a resin substrate
Resin substrate-1
Semi-bleached kraft paper (obtained from Totsuya Echo Co., Ltd.) coated with polyvinyl alcohol with a solid content concentration of 5% to a thickness of 1 μm, PET-30 (pentaerythritol triacrylate) 10 manufactured by Nippon Kayaku Co., Ltd. A composition for forming the resin substrate-1 was prepared by mixing 5 parts by weight of toluene, 5 parts by weight of toluene, and 0.6 parts by weight of 1-hydroxycyclohexylphenylketone (Irgacure 184 manufactured by BASF). The composition was coated on the semi-bleached kraft paper anchor-coated with polyvinyl alcohol so that the resin solid content after solvent volatilization had a thickness of 5 μm, and a measurement sample having the resin substrate-1 was prepared.
Resin substrate-2
10 parts by weight of PET-30 (pentaerythritol triacrylate) manufactured by Nippon Kayaku Co., Ltd., 5 parts by weight of PET-30 (pentaerythritol triacrylate) manufactured by Nippon Kayaku Co., Ltd., and FA-511A (dicyclopentenyl acrylate) manufactured by Hitachi Kasei. A measurement sample having the resin substrate-2 was prepared in the same manner except that the portion was replaced with 5 parts by weight.
Resin substrate-3
The resin substrate- 3 was prepared in the same manner except that 10 parts by weight of PET-30 (pentaerythritol triacrylate) manufactured by Nippon Kayaku Co., Ltd. was replaced with 10 parts by weight of PEG-400DA (polyethylene glycol diacrylate) manufactured by Nippon Kayaku Co., Ltd. A measurement sample having was prepared.
Resin substrate-4
A cycloolefin film (trade name: Zeonor) manufactured by Zeon Corporation was used as a measurement sample.
Resin substrate-5
A film prepared by forming a film of an acrylic resin to 40 μm according to the description of Example 1 of the international patent WO 2006-112223 was used as a measurement sample.

Inorganic substrate-1
The white transparent plate glass substrate manufactured by Kawamura Kuzo Co., Ltd. was designated as an inorganic substrate-1.
Inorganic substrate-2
The crystal substrate manufactured by Iwate Murata Manufacturing Co., Ltd. was designated as an inorganic substrate-2.
(2) Measurement of moisture permeability The moisture permeability of each substrate was measured using an L80-5000 type water vapor permeability meter (manufactured by System Instruments).

Table 4 below shows the measurement results of the moisture permeability of the substrate used in the examples of the present application. In Table 4, ND indicates that it is below the lower limit of measurement.

It can be seen that the resin substrate-3 does not satisfy the condition b) above.

<Example 1>
The resin substrate-1 is provided on a triacetyl cellulose film (TD-80U manufactured by Fuji Film Co., Ltd., hereinafter abbreviated as TAC film) so that the film thickness after formation is 5 μm, and the TAC film having the resin substrate-1 is provided. Was produced. The TAC film having the resin substrate-1 was immersed in an aqueous solution of sodium hydroxide having a pH of 11 for 10 minutes and then immersed in an aqueous solution having a pH of 6 for 1 minute. The TAC surface of the TAC film having the resin substrate-1 obtained by the treatment and the polarizing element prepared by using the above [Compound Example 1-5] were combined with a 4% polyvinyl alcohol aqueous solution (manufactured by Japan Vam & Poval). Adhesion was performed using NH-264 4% aqueous solution). Further, the TAC film subjected to only the saponification treatment was adhered using a 4% polyvinyl alcohol aqueous solution so that the polarizing element was sandwiched between the TAC films. An adhesive PTR-3000 manufactured by Nippon Kayaku Co., Ltd. is applied to the TAC surface of the film bonded with an adhesive so that the thickness after drying is 20 μm to form an adhesive layer, and the side on which the adhesive layer is formed is formed. Was bonded to glass to obtain a polarizing plate. That is, a polarizing plate to be a polarizing element / adhesive layer / TAC film / adhesive layer / glass produced by using the resin substrate-1 / TAC film / adhesive layer / [Compound Example 1-5] was obtained.

<Example 2>
In Example 1, the resin substrate-1 was changed to the resin substrate-2 in the same manner as in Example 1, and the resin substrate-2 / TAC film / adhesive layer / [Compound Example 1-5]. A polarizing plate to be a polarizing element / adhesive layer / TAC film / adhesive layer / glass prepared by using the above was obtained.

<Example 3>
In Example 1 above, the cycloolefin film / is the same as in Example 1 except that the TAC film on which the resin substrate-1 is formed is changed to a cycloolefin film (Zeonor manufactured by Nippon Zeon Co., Ltd.) to which corona treatment is applied. A polarizing plate to be a polarizing element / adhesive layer / TAC film / adhesive layer / glass produced by using the adhesive layer / [Compound Example 1-5] was obtained.

<Example 4>
The above-mentioned double-sided adhesive sheet was attached to both sides of the polarizing element using [Compound Example 1-5] used in Example 1, and glass was attached to one side and crystal was attached to one side. A polarizing plate to be a polarizing element / double-sided adhesive sheet / quartz prepared using the double-sided adhesive sheet / [Compound Example 1-5] was obtained.

<Example 5>
In the first embodiment, the TAC film on which the resin substrate-1 was formed was changed to the resin substrate-5 on which the easy-adhesive layer was formed, and the polarizing element using [Compound Example 1-5] was used in the above [Example 1]. Acrylic film / adhesive layer / polarizing element using [Compound Example 1-29] / adhesive layer / in the same manner as in Example 1 except that the polarizing element was changed to the polarizing element produced using Compound Example 1-29]. A polarizing plate of Example 5 was obtained, which was a TAC film / adhesive layer / glass.

<Example 6>
In the second embodiment, the polarizing element produced by using [Compound Example 1-5] was changed to the polarizing element produced by using [Compound Example 1-29] in the same manner as in Example 2. A polarizing plate to be a polarizing element / adhesive layer / TAC film / adhesive layer / glass produced by using the resin substrate-2 / TAC film / adhesive layer / [Compound Example 1-29] was obtained.

<Comparative example 1>
In the above Example 1, the polarizing element / adhesive layer produced by using the TAC film / adhesive layer / [Compound Example 1-5] in the same manner as in Example 1 except that the resin substrate-1 was not used. A polarizing plate of Comparative Example 1 having a TAC film / adhesive layer / glass was obtained.

<Comparative example 2>
Resin substrate-3 / TAC film / adhesive layer / [Compound Example 1-5] in the same manner as in Example 1 except that the resin substrate-3 was used instead of the resin substrate-1 in the first embodiment. A polarizing plate to be used as a polarizing element / adhesive layer / TAC film / adhesive layer / glass was obtained.

The obtained polarizing plates of Examples 1 to 6 and Comparative Examples 1 and 2 were placed in an environment of 90% RH and 80 ° C. for 1000 hours, and Ky (%) and Kz at 950 nm before and after this high temperature and high humidity treatment. Changes in each optical characteristic of (%), single transmittance (%), degree of polarization (%), and Rd were confirmed. The results are shown in Table 5.

As shown in Table 5 above, in Comparative Examples 1 and 2, the Ky at 950 nm after the application was significantly reduced from 79.82% to 48.58% and 79.25% to 49.83%, respectively. The single transmittance was significantly reduced from 39.97% to 24.92% and 39.67% to 25.47%, respectively. On the other hand, in Examples 1 to 6, Ky and the single transmittance changed only from 81.98% to 80.54% even in Example 6 in which the change in the single transmittance was the largest. The single transmittance changes from 42.30% to 41.43%, which is about 0.87%, indicating that the initial state is almost maintained. From this, it can be seen that the polarizing plates of Examples 1 to 6 have extremely high moist heat durability.

<Light resistance test>
Regarding the polarizing plates produced in Example 4 and Comparative Example 1, a xenon arc tester (manufactured by Suga Test Instruments Co., Ltd .; SX-75) was used at 150 W, an environmental temperature of 70 ° C., and an environmental humidity of 50%. From the side, Comparative Example 1 was subjected to a light irradiation test for 240 hours from the TAC film side. Changes in each optical characteristic of Ky (%), Kz (%), single transmittance (%), degree of polarization (%), and Rd at 950 nm before and after light irradiation were confirmed. The results are shown in Table 6.

From the results in Table 6, in the light resistance test, in Example 4, the change at 950 nm was only changed from 0.1145% to 0.2615%, but in Comparative Example 1, it was 0.1132 to 5.2350%. It has changed a lot. The degree of polarization was also maintained at 99% or more in Example 4, while it decreased to 88.08% in Comparative Example 1. In the two-color ratio (Rd), in Example 4, 29.2 was only changed to 23.0, but in Comparative Example 1, it decreased from 30.1 to 15.4. From the above, it can be seen that the polarizing plate of Example 4 has high light resistance in the near infrared region.

The polarizing plate of the present application is a polarizing plate that can have a high degree of polarization in the infrared region or the visible region to the infrared region and has high durability. The obtained polarizing plate has high light resistance even when exposed to strong light for a long time at high temperature and high humidity or high temperature. Therefore, the polarizing plate of the present application can be applied to sensors, lenses, switching elements, isolators, cameras, and in-vehicle devices such as indoor and outdoor measuring instruments and driver sensing modules, which require a high degree of polarization. In addition, it can be suitably used for devices that sense infrared rays, such as infrared panels and spatial infrared touch modules, and further conventional displays such as calculators, watches, laptop computers, word processors, LCD TVs, polarized lenses, polarized glasses, and cars. When used in combination with navigation, etc., it is possible to provide a module that utilizes infrared light as well as a visible display.

Claims

A polarizing plate including a polarizing element made of a hydrophilic polymer film containing a near-infrared absorbing dye and a substrate provided on one or both sides of the film.
A polarizing plate: the substrate having at least one of the following characteristics a) and b):
a) When the hydrophilic polymer film contains a boron compound, the boron contained in the hydrophilic polymer film after the polarizing plate is exposed to the polarizing plate in an environment of 90% RH and 80 ° C. for 1000 hours. When the mass of the compound is 100 before the exposure, it is maintained at 20 or more.
b) The moisture permeability of the substrate in an environment of 90% RH relative humidity and 40 ° C. based on the JIS Z 0208 moisture permeability test is 0 to 1500 g / m 2 in 24 hours.
The polarizing plate according to claim 1, wherein at least one of the substrates is a resin substrate having the characteristics of b).
The polarizing plate according to claim 2, wherein substrates are provided on both sides of the hydrophilic polymer film, and an inorganic substrate or a resin substrate having the characteristics b) is provided on the opposite side of the resin substrate.
The hydrophilic polymer film is composed of a polyvinyl alcohol-based resin, an amylose-based resin, a starch-based resin, a cellulosic resin, a polyacrylate-based resin, and a resin selected from the group consisting of derivatives thereof, and comprises a boron compound. The polarizing plate according to any one of claims 1 to 3, which is contained.
Claims 2 to 4, wherein the resin substrate contains one or more resins selected from the group consisting of silicon-based resins, (meth) acrylic-based resins, cycloolefin-based resins, polyester-based resins, and polycarbonate resins. The polarizing plate according to any one item.
Any one of claims 2 to 5, wherein the resin substrate contains a film obtained by polymerizing a polymerizable monomer composition containing a (meth) acrylate compound having three or more (meth) acryloyl groups in the molecule. The polarizing plate according to the section.
The polarizing plate according to claim 6, wherein the (meth) acrylate compound has any skeleton selected from the group consisting of a pentaerythritol skeleton, a neopentyl glycol skeleton, a trimethylolpropane skeleton, and a dicyclopentadiene skeleton.
The polarizing plate according to claim 6 or 7, wherein the (meth) acrylate compound is contained in an amount of 15% by mass or more based on the solid content concentration of all the monomers in the polymerizable monomer composition.
The polarizing plate according to any one of claims 3 to 8, wherein the inorganic substrate contains any one of glass, quartz, sapphire, crystal, and spinel.
The polarizing plate according to any one of claims 2 to 9, wherein the thickness of the resin substrate is 0.5 μm to 10 μm.
The polarizing plate according to any one of claims 4 to 10, wherein the hydrophilic polymer film contains a polyvinyl alcohol resin or a derivative thereof.
The polarizing plate according to any one of claims 1 to 11, wherein the near-infrared absorbing dye is an azo compound represented by the following formula (1).

(In the formula (1), A 1 is a phenyl group which may have a substituent, a naphthyl group which may have a substituent or a heterocyclic group which may have a substituent, and A 2 ,. A 3 and A 4 are independently phenyl groups which may have a substituent or a naphthyl group which may have a substituent, and k represents an integer of 0 or 1. R 1 represents an integer of 0 or 1. A hydroxy group, an alkoxy group having 1 to 4 carbon atoms or a substituted or unsubstituted amino group, m represents an integer of 0 to 5, M represents a hydrogen, a metal ion or an ammonium ion, and n is 1. of ~ 2 represents an integer. hydrogen atoms of the ring a and ring b are each independently may be substituted with a substituent R 1, either or both hydrogen atoms of the ring a and ring b is substituted It has been replaced by the group SO 3 M.)
A 2 , A 3 and A 4 in the above formula (1) are independently represented by the following formula (2) or formula (3), and at least one of A 2 , A 3 and A 4 is a formula ( The polarizing plate according to claim 12, which is represented by 2).

In the formula (2), R 2 is a carbon substituted with a hydroxy group, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a substituted or unsubstituted amino group or a sulfo group. It represents an alkoxy group of the number 1 to 4, m 2 represents an integer of 0 to 6. M represents a hydrogen, metal ion or ammonium ion, and n 3 represents an integer of 0 to 2).

In the formula (3), R 3 and R 4 are independently substituted with a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a hydroxy group, respectively. Represents an alkoxy group having 1 to 4 carbon atoms substituted with an alkoxy group of 1 to 4 or a sulfo group.)
The polarizing plate according to claim 12 or 13, wherein the azo compound of the above formula (1) is a compound represented by the following formula (4).

(In the formula (4), A 1 , A 2 , A 3 , A 4 , M, n and k are the same as those in the above formula (1), respectively. Also, one or both of the rings a and b. The hydrogen atom is substituted with the substituent SO 3 M.)
A 1 in the formula (1) or (4) is substituted with a hydroxy group, one or more substituents selected from the group consisting of substituted alkoxy group and a sulfo group having a carbon number of 1 to 4 sulfo groups The polarizing plate according to any one of claims 12 to 14, which is a naphthyl group.
The polarizing plate according to any one of claims 12 to 14, wherein A 1 is represented by the following formula (5) in the above formula (1) or (4).

(In equation (5), n 4 represents an integer of 1 to 2.)
The invention according to any one of claims 12 to 14, wherein A 1 in the above formula (1) or (4) is a phenyl group substituted with at least one substituent selected from a nitro group and a sulfo group. Polarizer.
Is a radical selected from the group consisting of groups above formula (1) or heterocyclic group which may have a substituent at A 1 in (4) is represented by (6) to (8), claim The polarizing plate according to any one of 12 to 14.

(X in formulas (6) to (8) is independently a halogen group, a nitro group, a hydroxy group, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a sulfo group. An aliphatic hydrocarbon group having 1 to 4 carbon atoms substituted with, an aliphatic hydrocarbon group having 1 to 4 carbon atoms substituted with a hydroxy group, and an aliphatic hydrocarbon group having 1 to 4 carbon atoms substituted with a carboxy group. A group, an alkoxy group having 1 to 4 carbon atoms substituted with a sulfo group, an alkoxy group having 1 to 4 carbon atoms substituted with a hydroxy group, or an alkoxy group having 1 to 4 carbon atoms substituted with a carboxy group. q 1 represents an integer of 0 to 4, q 2 represents an integer of 0 to 6. M represents a hydrogen, metal ion, or ammonium ion, and n 1 and n 2 are independent of 0 to 3, respectively. In each formula, * represents the bonding position with the azo bond.)
At least 700 to 1500 nm, a wavelength range in which the ratio of the absorbance of the axis showing the highest transmittance for polarized light to the absorbance of the axis showing the lowest transmittance for polarized light is 5 or more. The polarizing plate according to any one of claims 1 to 18.
The polarizing plate according to any one of claims 12 to 19, further comprising one or more kinds of organic dyes other than the azo compound represented by the above formula (1).
The polarizing plate according to claim 20, which indicates neutral gray.
An optical device including the polarizing plate according to any one of claims 1 to 21.
A display device including the polarizing plate according to any one of claims 1 to 21 or the optical device according to claim 22.