JP2020126276A - Polarizing plate - Google Patents

Abstract

To provide a polarizing plate which can suppress temporal reduction in optical performance and has high durability.SOLUTION: A polarizing plate contains a first cured product layer composed of a cured product of a curable composition containing a polymerizable compound and an adhesive layer containing an ionic compound on one surface of a polarizing film containing a dichroic dye in this order in a polyvinyl alcohol resin, in which the curable composition contains (A1) an oxetane compound having two or more oxetanyl groups and (A2) an aliphatic epoxy compound having two or more epoxy groups, the curable composition contains (A1) 15-70 mass% and (A2) 3-40 mass% with respect to 100 mass% of the total amount of the polymerizable compound, and a content of an oxetane compound (A3) having one oxetanyl group is 10 mass% or less with respect to 100 mass% of the total amount of the polymerizable compound.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a polarizing plate, and more particularly to a polarizing plate having a cured product layer composed of a cured product of a curable composition on one surface of a polarizing film containing a dichroic dye.

Conventionally, a polarizing plate has been used by being bonded to an image display element such as a liquid crystal cell or an organic EL display element in various image display panels such as a liquid crystal display panel and an organic electroluminescence (organic EL) display panel. As such a polarizing plate, on one or both surfaces of a polarizing film in which a dichroic dye such as iodine or a dichroic dye is adsorbed and aligned on a polyvinyl alcohol-based resin film, an adhesive layer is used to form a triacetyl cellulose film. There is known a polarizing plate having a configuration in which protective films as described above are laminated (for example, Patent Document 1). Such a polarizing plate is an image display device such as a liquid crystal cell or an organic EL display device via an adhesive in a form in which various optical layers such as a retardation film and an optical compensation film are further laminated if necessary. It is pasted on to form an image display panel.

JP2012-208250A

When the image display panel is charged with static electricity, a problem occurs in its display function. Therefore, blending an antistatic agent in the polarizing plate may prevent electrostatic charge. For example, an antistatic agent may be blended in the pressure-sensitive adhesive layer in the polarizing plate. In this case, the polarizing plate has an optical performance such as a polarizing property when used for a long period of time and/or in a high temperature and high humidity environment. May decrease over time. The reason for this is considered to be that the antistatic agent in the adhesive layer migrates to the polarizing film over time and interacts with the dichroic dye such as iodine in the polarizing film, resulting in a decrease in the polarizing property. In such a polarizing plate whose optical performance is deteriorated, the image display performance may be deteriorated.

Then, the present invention solves the above-mentioned problems peculiar to a polarizing plate having an antistatic function, and can suppress deterioration of optical performance with time, and provide a polarizing plate having high durability. And

The present invention provides the following preferred embodiments.
[1] A first cured product layer composed of a cured product of a curable composition containing a polymerizable compound on one surface of a polarizing film containing a dichroic dye in a polyvinyl alcohol resin, and an ionic compound A pressure-sensitive adhesive layer containing a polarizing plate containing in this order, the polymerizable compound,
(A1) containing an oxetane compound having two or more oxetanyl groups, and (A2) an aliphatic epoxy compound having two or more epoxy groups,
The curable composition, relative to the total amount of the polymerizable compound 100 mass%,
(A1) 15 to 70 mass%, and (A2) 3 to 40 mass%
Containing
A polarizing plate in which the content of the oxetane compound (A3) having one oxetanyl group is 10% by mass or less based on 100% by mass of the total amount of the polymerizable compounds.
[2] A first transparent protective film is provided between the first cured product layer and the adhesive layer, and the first transparent protective film is a 50% by mass potassium iodide aqueous solution at 23° C. and 60% RH in an air atmosphere. It is immersed for 4.5 hours in the lower atmosphere, taken out, washed with water at 23° C. for 15 seconds in the air, and dried for 15 hours in the dark at 23° C. in the air. The polarizing plate according to the above [1], which is 5% or more higher than the absorbance of.
[3] The polarizing plate according to the above [1] or [2], wherein a second transparent protective film is provided on a surface of the polarizing film opposite to the first cured material layer side with a second cured material layer interposed therebetween. ..

ADVANTAGE OF THE INVENTION According to this invention, the deterioration of optical performance over time can be suppressed and a polarizing plate with high durability can be provided.

FIG. 3 is a cross-sectional view showing a structure which is one mode of a structure of a polarizing plate. FIG. 3 is a cross-sectional view showing a structure which is one mode of a structure of a polarizing plate.

The polarizing plate of the present invention comprises a first cured product layer composed of a cured product of a curable composition containing a polymerizable compound on one surface of a polarizing film containing a dichroic dye in a polyvinyl alcohol resin. , And an adhesive layer containing an ionic compound in this order.

Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the spirit of the present invention.

The configuration of one embodiment of the polarizing plate of the present invention will be described based on FIG. The polarizing plate (10) of the present invention has a structure in which the first cured material layer (2) and the adhesive layer (3) are laminated in this order on one surface of the polarizing film (1). If necessary, a second transparent protective film (5) may be provided on the surface of the polarizing film (1) opposite to the first cured product layer side via the second cured product layer (4). ..

The polarizing plate (10) of the present invention has a structure in which the first cured product layer (2) and the adhesive layer (3) are laminated in this order on one surface of the polarizing film (1), and further comprises the first A first transparent protective film (6) may be provided between the cured product layer (2) and the adhesive layer (3). This embodiment is shown in FIG. If necessary, the polarizing plate (10) has a second transparent protective film (5) on the surface of the polarizing film (1) opposite to the first cured product layer via the second cured product layer (4). ) May be provided.

The polarizing plate (10) of the present invention is arranged on one surface of the liquid crystal cell (X) via an adhesive layer, and a polarizing plate which is the same as or different from the polarizing plate of the present invention is arranged on the other surface of the liquid crystal cell. The liquid crystal display panel is configured by arranging the liquid crystal display panel in the.
Hereinafter, each component of the polarizing plate of the present invention will be described in detail.

[First cured product layer]
The polarizing plate of the present invention contains the first cured material layer on one surface of the polarizing film. The first cured product layer is composed of a cured product of a curable composition containing a polymerizable compound, and the curable composition is
It contains (A1) an oxetane compound having two or more oxetanyl groups, and (A2) an aliphatic epoxy compound having two or more epoxy groups.

(A1) The oxetane compound having two or more oxetanyl groups (hereinafter, may be referred to as “oxetane compound (A1)”) is a compound having two or more oxetanyl groups (oxetane ring) in the molecule. The oxetane compound (A1) may be aliphatic, alicyclic or aromatic. Examples of the oxetane compound (A1) include 1,4-bis[{(3-ethyloxetane-3-yl)methoxy}methyl]benzene (also called xylylenebisoxetane) and bis(3-ethyl-3-). Examples include oxetanylmethyl) ether and the like. These oxetane compounds (A1) may be used alone or in combination of different kinds. By containing the oxetane compound (A1) having two or more oxetanyl groups as the polymerizable compound, it is possible to obtain a dense cured product having a high crosslink density by curing the curable composition. Therefore, by providing a cured product layer composed of such a cured product between the polarizing film and the adhesive layer, it is possible to effectively suppress the movement of the ionic compound from the adhesive layer.

The aliphatic epoxy compound (A2) having two or more epoxy groups (hereinafter sometimes referred to as “aliphatic epoxy compound (A2)”) has at least two epoxy rings bonded to an aliphatic carbon atom in the molecule. It is a compound having three or more. Examples of the aliphatic epoxy compound (A2) include bifunctional epoxy compounds such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether and neopentyl glycol diglycidyl ether; trimethylolpropane tri Trifunctional or higher functional epoxy compounds such as glycidyl ether and pentaerythritol tetraglycidyl ether; 1 epoxy group directly bonded to alicyclic ring, such as 4-vinylcyclohexenedioxide and limonenedioxide, and an aliphatic carbon atom Epoxy compounds having an oxirane ring. The aliphatic epoxy compound (A2) may be used alone or in combination of a plurality of different kinds.

Among them, a bifunctional epoxy compound (also referred to as an aliphatic diepoxy compound) having two oxirane rings bonded to an aliphatic carbon atom in the molecule is preferable from the viewpoint of the adhesiveness between the polarizing film and the transparent protective film, An aliphatic diepoxy compound represented by the following formula (I) is more preferable. In particular, when the curable composition contains an aliphatic diepoxy compound represented by the following formula (I), a curable composition having a low viscosity and easy to apply can be obtained.

In formula (I), Z is an alkylene group, an alkylidene group having 3 or 4 carbon atoms having 1 to 9 carbon atoms, a divalent alicyclic hydrocarbon group, or a group of the formula ^{_{-C m H 2m -Z 1 -C n}} H, _2n - is a divalent group represented by. Further, the formula ^{_{-C m H 2m -Z 1 -C n}} H 2n - in, -Z ¹ - is, -O -, - CO-O -, - O-CO -, - SO 2 -, - SO- , Or —CO—, and m and n each independently represent an integer of 1 or more, but the sum of both is 9 or less.
The divalent alicyclic hydrocarbon group may be, for example, a divalent alicyclic hydrocarbon group having 4 to 8 carbon atoms, and examples thereof include the divalent group represented by the formula (I-1). To be

The aliphatic diepoxy compound represented by the above formula (I) is specifically a diglycidyl ether of alkanediol, a diglycidyl ether of oligoalkylene glycol up to about 4 repetitions, or a diglycidyl ether of alicyclic diol. Is.

Examples of the diol (glycol) capable of forming the aliphatic diepoxy compound represented by the above formula (I) include ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2- Butyl-2-ethyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-2,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 3 -Methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 3, Alkanediols such as 5-heptanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol;
Oligoalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol;
Examples thereof include alicyclic diols such as cyclohexanediol and cyclohexanedimethanol.

In the present invention, the aliphatic diepoxy compound represented by the above formula (I) is 1,4-butanediol diglycidyl ether, 1,6-butane, from the viewpoint that a curable composition having a low viscosity and easily applied can be obtained. Hexanediol diglycidyl ether and neopentyl glycol diglycidyl ether are preferred. 1,6-hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, and pentaerythritol polyglycidyl ether are preferable from the viewpoint of maintaining the optical performance. The aliphatic diepoxy compounds may be used alone or in combination of different kinds.

In the present invention, the curable composition is 15 to 70% by mass, preferably 35 to 60% by mass, and more preferably 45 to 55% by mass of the oxetane compound (A1) with respect to 100% by mass of the total amount of the polymerizable compound. )including. When the content of the oxetane compound (A1) in the curable composition is at least the above lower limit value, the migration of the ionic compound can be sufficiently suppressed. When the content of the oxetane compound (A1) in the curable composition is at most the above upper limit, curing will proceed rapidly, and a cured product layer having sufficient hardness can be easily formed.

When the curable composition contains an aliphatic epoxy compound (A2), the curable composition is 3 to 40% by mass, preferably 5 to 25% by mass with respect to 100% by mass of the total amount of the polymerizable compounds. , More preferably 5 to 15% by mass of the aliphatic epoxy compound (A2). When the content of the aliphatic epoxy compound (A2) in the curable composition is at least the above lower limit value, a composition having a low viscosity and easy to apply can be obtained. When the content of the aliphatic epoxy compound (A2) in the curable composition is at most the above upper limit, the elasticity of the cured product after curing does not become too low, and cracking due to heat shrinkage of the polarizing film can be suppressed. ..

The curable composition may include an oxetane compound (A3) having one oxetanyl group. The content of the oxetane compound (A3) having one oxetanyl group is 10% by mass or less, preferably 5% by mass or less, and even 0% by mass, with respect to 100% by mass of the total amount of the polymerizable compound. Good. When the content of the oxetane compound (A3) having one oxetanyl group is at most the above upper limit value, the crosslink density is high and a dense cured product can be easily obtained.

The curable composition may contain a compound (A4) having two or more epoxy groups other than the aliphatic epoxy compound (A2). Examples of the compound (A4) having two or more epoxy groups include an alicyclic epoxy compound (A4-1) having two or more epoxy groups (hereinafter, referred to as “alicyclic epoxy compound (A4-1)”). And an aromatic epoxy compound (A4-2) having two or more epoxy groups (hereinafter sometimes referred to as “aromatic epoxy compound (A4-2)”).

The alicyclic epoxy compound (A4-1) is a compound having two or more epoxy groups bonded to the alicyclic ring in the molecule. “Epoxy group bonded to alicyclic ring” means the following formula (a):
Means a bridging oxygen atom —O— in the structure represented by. In the above formula (a), m is an integer of 2-5.

A compound in which two or more groups in the form of removing one or more hydrogen atoms in (CH ₂ ) _m in the above formula (a) are bonded to another chemical structure is an alicyclic epoxy compound (A4 -1) can be obtained. One or more hydrogen atoms in (CH ₂ ) _m may be optionally substituted with a linear alkyl group such as a methyl group or an ethyl group. The alicyclic epoxy compound (A4-1) may be used alone or in combination of a plurality of different kinds.

Among them, an epoxycyclopentane structure [m=3 in the above formula (a)] or an epoxycyclohexane from the viewpoint of a cured product having a high glass transition temperature and excellent adhesion between the polarizing film and the transparent protective film. An alicyclic epoxy compound having a structure [m=4 in the above formula (a)] is preferable, and an alicyclic diepoxy compound represented by the following formula (II) is more preferable. In particular, when the curable composition contains an aliphatic diepoxy compound represented by the following formula (II), the cured product layer after the curable composition is cured has high elasticity, and the heat shrinkage of the polarizing film. It is possible to suppress cracking due to.

In formula (II), R ¹ and R ² each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, but when the alkyl group has 3 or more carbon atoms, it may have an alicyclic structure. .. The alkyl group having 1 to 6 carbon atoms may be a linear or branched alkyl group, and examples of the alkyl group having an alicyclic structure include a cyclopropyl group, a cyclobutyl group and a cyclopentyl group.

In formula (II), X is an oxygen atom, an alkanediyl group having 1 to 6 carbon atoms or the following formulas (IIa) to (IId):
Is a divalent group represented by any of the above.
Examples of the alkanediyl group having 1 to 6 carbon atoms include methylene group, ethylene group, propane-1,2-diyl group and the like.

When X in the formula (II) is a divalent group represented by any of the formulas (IIa) to (IId), Y ^{1 to} Y ⁴ in each formula each independently have 1 to 20 carbon atoms. When it is an alkanediyl group and the alkanediyl group has 3 or more carbon atoms, it may have an alicyclic structure.

Examples of the alicyclic diepoxy compound include the following compounds A to M. The chemical formulas A to M shown below correspond to the compounds A to M, respectively.

A: 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, B: 3,4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexanecarboxylate,
C: ethylene bis(3,4-epoxycyclohexanecarboxylate),
D: Bis(3,4-epoxycyclohexylmethyl) adipate,
E: Bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate,
F: diethylene glycol bis(3,4-epoxycyclohexyl methyl ether),
G: ethylene glycol bis(3,4-epoxycyclohexyl methyl ether),
H: 2,3,14,15-diepoxy-7,11,18,21-tetraoxatrispyro[5.2.2.2.5.2]henicosane,
I: 3-(3,4-epoxycyclohexyl)-8,9-epoxy-1,5-dioxaspiro[5.5]undecane,
J: 4-vinylcyclohexenedioxide,
K: Limonenedioxide,
L: bis(2,3-epoxycyclopentyl) ether,
M: dicyclopentadiene dioxide.

In the present invention, the alicyclic diepoxy compound is preferably 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate from the industrial viewpoint such as availability. The alicyclic diepoxy compounds may be used alone or in combination of different kinds.

The aromatic epoxy compound (A4-2) is a compound having two or more epoxy groups and one or more aromatic rings. Examples of the aromatic epoxy compound (A4-2) include the following.
For example, a glycidyl ether compound of bisphenol A, bisphenol F, or a compound obtained by further adding an alkylene oxide thereto or an epoxy novolac resin;
Glycidyl ethers of aromatic compounds having two or more phenolic hydroxyl groups such as resorcinol, hydroquinone and catechol;
A glycidyl ether compound of an aromatic compound having two or more alcoholic hydroxyl groups such as benzenedimethanol, benzenediethanol, and benzenedibutanol;
Glycidyl ester of polybasic acid aromatic compound having two or more carboxylic acids such as phthalic acid, terephthalic acid and trimellitic acid;
Glycidyl esters of benzoic acids such as benzoic acid, toluic acid and naphthoic acid;
Styrene oxide or divinylbenzene epoxide, etc.
The aromatic epoxy compounds (A4-2) may be used alone or in combination of different kinds.

Among them, from the viewpoint of reducing the viscosity of the curable composition, a glycidyl ether compound of an aromatic compound having two or more alcoholic hydroxyl groups, a glycidyl ether compound of a polyhydric phenol, a glycidyl ester of a benzoic acid, a glycidyl of a polybasic acid It preferably contains at least one selected from the group of esters, styrene oxides or epoxidized products of divinylbenzene.

Further, as the aromatic epoxy compound (A4-2), those having an epoxy equivalent of 80 to 500 are preferable because they improve the curability of the curable composition. The aromatic epoxy compounds (A4-2) may be used alone or in combination of different kinds.

In a preferred embodiment of the present invention, the curable resin composition contains the aliphatic diepoxy compound represented by the above formula (I) and the alicyclic diepoxy compound represented by the above formula (II). In this case, a dense cured product layer having a high crosslink density can be obtained, and the movement of the ionic compound from the adhesive layer can be effectively suppressed. Further, when the curable composition contains an aromatic epoxy compound (A4-2), a hydrophobic cured product layer can be formed, and migration of the ionic compound can be further suppressed.

When the curable composition contains an alicyclic epoxy compound (A4-1), the curable composition is preferably 10 to 70 mass%, more preferably 100 mass% of the total amount of the polymerizable compounds. Contains 25 to 60% by mass, and more preferably 25 to 50% by mass of the alicyclic epoxy compound (A4-1). When the content of the alicyclic epoxy compound (A4-1) in the curable composition is within the above range, curing by irradiation with active energy rays proceeds rapidly, and a cured product layer having sufficient hardness is easily formed. can do.

When the curable composition contains an aromatic epoxy compound (A4-2), the curable composition is preferably 0.1 to 20 mass% with respect to 100 mass% of the total amount of the polymerizable compounds, and more preferably It preferably contains 5 to 20% by mass of the aromatic epoxy compound (A4-2). When the content of the aromatic epoxy compound (A4-2) in the curable composition is at least the above lower limit value, the cured product tends to be hydrophobic, and the permeation of the ionic compound can be further suppressed. When the content of the aromatic epoxy compound (A4-2) in the curable composition is at most the above upper limit, the adhesiveness with the polarizing film will be good.

The curable composition may contain another polymerizable compound (A5) different from the polymerizable compounds (A1) to (A4). Examples of other polymerizable compounds (A5) include monoepoxy compounds. The other polymerizable compound (A5) may be an aliphatic compound, an alicyclic compound or an aromatic compound, or a mixture thereof.
When the curable composition contains another polymerizable compound (A5) as a polymerizable compound, the content thereof is based on 100% by mass of the total amount of the polymerizable compounds (A1) to (A5) contained in the curable composition. Is preferably 10% by mass or less, and more preferably 5% by mass or less.

The curable composition usually contains a polymerization initiator for initiating polymerization. Examples of the polymerization initiator include a cationic photopolymerization initiator (B). The cationic photopolymerization initiator is one which, when irradiated with an active energy ray such as visible light, ultraviolet rays, X-rays, or an electron beam, generates a cationic species or a Lewis acid to initiate a polymerization reaction of the cationically polymerizable compound. .. Since the cationic photopolymerization initiator acts catalytically with light, it is excellent in storage stability and workability even when mixed with the cationic photopolymerizable compound. Examples of the compound that produces a cationic species or a Lewis acid upon irradiation with active energy rays include onium salts such as aromatic iodonium salts and aromatic sulfonium salts, aromatic diazonium salts, iron-arene complexes, and the like.

The aromatic iodonium salt is a compound having a diaryliodonium cation, and the cation can typically include a diphenyliodonium cation. The aromatic sulfonium salt is a compound having a triarylsulfonium cation, and typical examples of the cation include a triphenylsulfonium cation and 4,4′-bis(diphenylsulfonio)diphenylsulfide cation. The aromatic diazonium salt is a compound having a diazonium cation, and typical examples of the cation include a benzenediazonium cation. Further, the iron-arene complex is typically a cyclopentadienyl iron(II)arene cation complex salt.

The cations shown above pair with anions (anions) to form a photocationic polymerization initiator. Specific examples of the anions constituting the photocationic polymerization initiator include special phosphorus anions [(Rf) _n PF _6-n ] ^- , hexafluorophosphate anions PF ₆ ^- , hexafluoroantimonate anions SbF ₆ ^- , pentafluoro. There are hydroxyantimonate anion SbF ₅ (OH) ⁻ , hexafluoroarsenate anion AsF ₆ ⁻ , tetrafluoroborate anion BF ₄ ⁻ , tetrakis(pentafluorophenyl)borate anion B(C ₆ F ₅ ) ₄ ^{− and the} like. Among them, from the viewpoint of safety of the curability and the resulting cured product layer of the cationically polymerizable compound, a special phosphate based anionic _{[(Rf) n PF 6-} n] -, hexafluorophosphate anion PF ₆ ^- it is preferably ..

The photocationic polymerization initiator (B) may be used alone or in combination of two or more. Among them, the aromatic sulfonium salt is preferably used because it has an ultraviolet absorbing property even in a wavelength region around 300 nm, and thus it is excellent in curability and can give a cured product having good mechanical strength and adhesive strength.

The amount of the photocationic polymerization initiator (B) is usually 0.5 to 10 parts by mass, preferably 6 parts by mass or less, relative to 100 parts by mass of the polymerizable compound. By blending 0.5 parts by mass or more of the cationic photopolymerization initiator (B), the polymerizable compound can be sufficiently cured, and the cured product layer composed of the obtained cured product has high mechanical strength and adhesion. Strength and can be given. On the other hand, if the amount is excessively large, the product from the photocationic polymerization initiator may react with the hydroxyl group of the polyvinyl alcohol-based resin forming the polarizing film, and the optical performance of the polarizing film may be deteriorated.

In the present invention, the curable composition may include additives generally used in the curable composition, if necessary. Examples of such additives include ion trap agents, antioxidants, chain transfer agents, polymerization accelerators (polyols, etc.), sensitizers, sensitization aids, light stabilizers, tackifiers, thermoplastic resins. , Fillers, flow regulators, plasticizers, defoamers, leveling agents, silane coupling agents, dyes, antistatic agents, and ultraviolet absorbers.

The photosensitizer is a compound that exhibits maximum absorption at a wavelength longer than the maximum absorption wavelength of the photocationic polymerization initiator (B) and accelerates the polymerization initiation reaction by the photocationic polymerization initiator (B). The photosensitizer aid is a compound that further promotes the action of the photosensitizer. Depending on the type of protective film, it may be preferable to blend such a photosensitizer and further a photosensitization aid.

The photosensitizer is preferably a compound that exhibits maximum absorption for light having a wavelength longer than 380 nm. The cationic photopolymerization initiator (B) has a maximum absorption at a wavelength near 300 nm or a shorter wavelength, generates a cationic species or a Lewis acid in response to light having a wavelength near that wavelength, and undergoes cationic polymerization of a polymerizable compound. However, if the above-mentioned photosensitizer is blended, it becomes sensitive to light having a longer wavelength, particularly longer than 380 nm. As such a photosensitizer, anthracene compounds are advantageously used. Specific examples of the anthracene-based photosensitizer include the following compounds.

9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, 9,10-diisopropoxyanthracene, 9,10-dibutoxyanthracene, 9,10-dipentyloxyanthracene, 9, 10-dihexyloxyanthracene, 9,10-bis(2-methoxyethoxy)anthracene, 9,10-bis(2-ethoxyethoxy)anthracene, 9,10-bis(2-butoxyethoxy)anthracene, 9,10-bis (3-Butoxypropoxy)anthracene, 2-methyl- or 2-ethyl-9,10-dimethoxyanthracene, 2-methyl- or 2-ethyl-9,10-diethoxyanthracene, 2-methyl- or 2-ethyl- 9,10-dipropoxyanthracene, 2-methyl- or 2-ethyl-9,10-diisopropoxyanthracene, 2-methyl- or 2-ethyl-9,10-dibutoxyanthracene, 2-methyl- or 2- Ethyl-9,10-dipentyloxyanthracene, 2-methyl- or 2-ethyl-9,10-dihexyloxyanthracene and the like.

In the polarizing plate of the present invention, the first cured material layer includes, for example, polymerizable compounds (A1) to (A2) and a cationic photopolymerization initiator (B), and, if necessary, polymerizable compounds (A1) to (A1). The curable composition obtained by mixing the polymerizable compounds (A3) to (A5) other than A2) and the additive is used on the polarizing film or when the first transparent protective film is used. It can be formed by coating on a transparent protective film, irradiating with active energy rays such as ultraviolet rays and electron beams, and curing the applied curable composition. When a layer made of a curable composition is irradiated with an active energy ray, a cationic species or a Lewis acid is generated from the photocationic polymerization initiator. The cationic compound or Lewis acid causes the polymerizable compound to polymerize even after irradiation with the active energy ray, whereby the curable composition is cured and a cured product layer is formed.

In the polarizing plate of the present invention, the thickness of the first cured product layer is not particularly limited, but is preferably in the range of 0.5 to 20 μm, more preferably 1 to 10 μm. When the thickness of the first cured product layer is within the range of the lower limit value or more, the migration of the ionic compound can be effectively suppressed. When the thickness of the first cured product layer is equal to or less than the upper limit value, the curable composition can be sufficiently cured, and the first cured product layer having high hardness can be obtained.

The polarizing plate of the present invention comprises a first cured product layer composed of a cured product of the curable composition, between the polarizing film and the adhesive layer, or between the polarizing film and the transparent protective film. This can prevent the ionic compound contained in the adhesive layer from moving to the polarizing film. In particular, in a high temperature and high humidity environment, the migration of ionic compounds is accelerated by the intrusion of moisture from the outside, but this can be effectively suppressed in the polarizing plate of the present invention. Therefore, the polarizing plate of the present invention can maintain the optical performance.
The first cured material layer also serves as an adhesive layer that bonds the polarizing film and the transparent protective film.

[Adhesive layer]
As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, conventionally known pressure-sensitive adhesives can be used without particular limitation. For example, a pressure-sensitive adhesive having a base polymer such as an acrylic type, a rubber type, a urethane type, a silicone type, or a polyvinyl ether type can be used. Can be used. Further, it may be an energy ray curable adhesive, a thermosetting adhesive, or the like. Among these, a pressure-sensitive adhesive using an acrylic resin as a base polymer, which is excellent in transparency, adhesive strength, reworkability, weather resistance, heat resistance, etc., is preferable.

In the present invention, when the adhesive layer contains an acrylic resin, the acrylic resin is not particularly limited and conventionally known ones can be used, but from the viewpoint of adhesiveness and reworkability, the present invention It is preferable that the pressure-sensitive adhesive layer included in the polarizing plate of (1) contains the following acrylic resin (P).

The acrylic resin (P) has the following formula (b):
[In the formula, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 1 to 14 carbon atoms which may be substituted with an alkoxy group having 1 to 10 carbon atoms. ]
An unsaturated monomer (P2) having a structural unit derived from a (meth)acrylic acid alkyl ester (P1) represented by the above as a main component and further having a polar functional group (hereinafter, referred to as “polar functional group-containing monomer”). It may be referred to as)) is an acrylic resin containing a structural unit derived from.
Here, in the present specification, (meth)acrylic acid means that either acrylic acid or methacrylic acid may be used, and in addition, “(meth)” when referring to (meth)acrylate has the same meaning. Is.

In the above formula (b) of the (meth)acrylic acid alkyl ester (P1) which is the main structural unit of the acrylic resin (P), R ₁ is a hydrogen atom or a methyl group, and R ₂ is a C 1-14 carbon atom. It is an alkyl group. The hydrogen atom in each group of the alkyl group represented by R ₂ may be substituted with an alkoxy group having 1 to 10 carbon atoms.

In the (meth)acrylic acid alkyl ester (P1) represented by the formula (b), R ₂ is an unsubstituted alkyl group, and specifically, methyl acrylate, ethyl acrylate, propyl acrylate, acryl Linear alkyl acrylates such as n-butyl acrylate, n-octyl acrylate, and lauryl acrylate; branched alkyl acrylates such as isobutyl acrylate, 2-ethylhexyl acrylate, and isooctyl acrylate A linear alkyl methacrylate ester such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, n-octyl methacrylate, and lauryl methacrylate; isobutyl methacrylate, 2-ethylhexyl methacrylate, And branched alkyl methacrylates such as isooctyl methacrylate. Among these, n-butyl acrylate is preferable, and specifically, n-butyl acrylate is preferably 50% by mass or more based on the total amount of all monomers constituting the acrylic resin (P).

As the (meth)acrylic acid alkyl ester represented by the formula (b), when R ₂ is an alkyl group substituted with an alkoxy group, that is, an alkoxyalkyl group, specifically, 2-methoxyethyl acrylate, Examples include ethoxymethyl acrylate, 2-methoxyethyl methacrylate, ethoxymethyl methacrylate and the like.

These (meth)acrylic acid alkyl esters (P1) may be used alone or in combination of different kinds.

In the polar functional group-containing monomer (P2), the polar functional group can be a free carboxyl group, a hydroxyl group, an amino group, a heterocyclic group including an epoxy ring, or the like. The polar functional group-containing monomer is preferably a (meth)acrylic acid compound having a polar functional group. As examples thereof, unsaturated monomers having a free carboxyl group such as acrylic acid, methacrylic acid, and β-carboxyethyl acrylate; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, ( Unsaturated monomers having a hydroxyl group such as 2- or 3-chloro-2-hydroxypropyl (meth)acrylate and diethylene glycol mono(meth)acrylate; acryloylmorpholine, vinylcaprolactam, N-vinyl-2-pyrrolidone, tetrahydrofur Unsaturated monomers having a heterocyclic group such as furyl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, glycidyl (meth)acrylate, and 2,5-dihydrofuran An unsaturated monomer having an amino group different from a heterocycle such as N,N-dimethylaminoethyl (meth)acrylate can be exemplified. The polar functional group is preferably a free carboxyl group, a hydroxyl group, an amino group or an epoxy ring. These polar functional group-containing monomers may be used alone or in combination of different kinds.

Among these, it is preferable to include an unsaturated monomer having a hydroxyl group as one of the polar functional group-containing monomers (P2) constituting the acrylic resin (P). In addition to the unsaturated monomer having a hydroxyl group, it is also effective to use an unsaturated monomer having another polar functional group, for example, an unsaturated monomer having a free carboxyl group in combination.

In the acrylic resin (P), the structural unit derived from the (meth)acrylic acid alkyl ester (P1) represented by the above formula (b) is 80 relative to the total amount of all monomers constituting the acrylic resin (P). The amount is preferably from 96 to 96% by mass, more preferably from 82% by mass or more, and even more preferably from 94% by mass or less. The structural unit derived from the polar functional group-containing monomer (P2) is preferably 0.1 to 5 mass% with respect to the total amount of all monomers constituting the acrylic resin (P), and more preferably It is 0.5% by mass or more, and more preferably 3% by mass or less.

In the polarizing plate of the present invention, the acrylic resin (P) that can form the adhesive layer includes the (meth)acrylic acid alkyl ester (P1) represented by the above formula (b) and the polar functional group-containing monomer (P2). May contain structural units derived from different monomers. Examples of these include unsaturated monomers (P3) having one olefinic double bond and at least one aromatic ring in the molecule (hereinafter, referred to as “aromatic ring-containing monomer”). ) Derived structural unit, a structural unit derived from a (meth)acrylic acid ester having an alicyclic structure in the molecule, a structural unit derived from a styrene-based monomer, a structural unit derived from a vinyl-based monomer, a molecule Examples thereof include structural units derived from a monomer having a plurality of (meth)acryloyl groups.

The unsaturated monomer having one olefinic double bond and at least one aromatic ring in the molecule (aromatic ring-containing monomer) (P3) is a group containing an olefinic double bond (meta). Those having an acryloyl group are preferred. Examples thereof include benzyl (meth)acrylate and neopentyl glycol benzoate (meth)acrylate. Among them, the following formula (c):
[In the formula, R ₃ represents a hydrogen atom or a methyl group, n is an integer of 1 to 8, and R ₄ represents a hydrogen atom, an alkyl group, an aralkyl group or an aryl group]
An aromatic ring-containing (meth)acrylic compound represented by is preferable.

In the above formula (c) representing an aromatic ring-containing (meth)acrylic compound, when R ₄ is an alkyl group, its carbon number can be 1 to 9, and when it is also an aralkyl group, its carbon number is 7-11, and when it is an aryl group, its carbon number can be 6-10. As the alkyl group having 1 to 9 carbon atoms, methyl, butyl, nonyl, etc., as the aralkyl group having 7 to 11 carbon atoms, benzyl, phenethyl, naphthylmethyl, etc., and as the aryl group having 6 to 10 carbon atoms, phenyl, Examples include trill and naphthyl.

Specific examples of the aromatic ring-containing (meth)acrylic compound of the formula (c) include 2-phenoxyethyl (meth)acrylate, 2-(2-phenoxyethoxy)ethyl (meth)acrylate, and ethylene oxide-modified nonylphenol ( Examples thereof include (meth)acrylic acid ester and 2-(o-phenylphenoxy)ethyl (meth)acrylate. These aromatic ring-containing monomers may be used alone or in combination of different kinds. Among these, 2-phenoxyethyl (meth)acrylate [compound of R ₄ =H, n=1 in the above formula (c)], 2-(o-phenylphenoxy)ethyl (meth)acrylate [the above formula In (c), R ₄ =o-phenyl, compound with n=1], or 2-(2-phenoxyethoxy)ethyl (meth)acrylate [in the above formula (c), R ₄ =H, n=2] [Compound of] is suitable as one of the aromatic ring-containing monomers (P3) constituting the acrylic resin (P).

The alicyclic structure is a cycloparaffin structure having 5 or more carbon atoms, preferably 5 to 7 carbon atoms. Specific examples of the acrylate ester having an alicyclic structure include isobornyl acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, cyclododecyl acrylate, methyl cyclohexyl acrylate, trimethyl cyclohexyl acrylate, tert-butyl cyclohexyl acrylate. , Cyclohexyl phenyl acrylate, α-ethoxy acrylate, and the like, and specific examples of the methacrylate having an alicyclic structure include isobornyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, cyclododecyl methacrylate. , Methyl cyclohexyl methacrylate, trimethyl cyclohexyl methacrylate, tert-butyl cyclohexyl methacrylate, cyclohexyl phenyl methacrylate and the like.

Specific examples of styrene-based monomers include styrene, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, and octylstyrene. Alkyl styrene; halogenated styrene such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, and iodostyrene; and nitrostyrene, acetylstyrene, methoxystyrene, divinylbenzene, and the like.

Specific examples of vinyl monomers include fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, and vinyl laurate; halogenated vinyl chloride and vinyl bromide. Vinyl; vinylidene halides such as vinylidene chloride; nitrogen-containing aromatic vinyls such as vinylpyridine, vinylpyrrolidone, and vinylcarbazole; conjugated diene monomers such as butadiene, isoprene, and chloroprene; and also acrylonitrile, methacryl Examples include ronitrile and the like.

Specific examples of the monomer having a plurality of (meth)acryloyl groups in the molecule include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 1,9-nonane. Two (meth)acrylates in the molecule, such as diol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and tripropylene glycol di(meth)acrylate. ) Monomers having an acryloyl group; monomers having three (meth)acryloyl groups in the molecule such as trimethylolpropane tri(meth)acrylate can be mentioned.

Monomers different from the (meth)acrylic acid alkyl ester (P1) represented by the formula (b) and the polar functional group-containing monomer (P2) may be used alone or in combination of two or more kinds. it can. When included in the pressure-sensitive adhesive, the structural unit derived from a monomer different from the (meth)acrylic acid alkyl ester (P1) and the polar functional group-containing monomer (P2) in the acrylic resin (P) is the resin. It is usually contained in an amount of 0 to 20 parts by mass, preferably 0 to 10 parts by mass, relative to 100 parts by mass of the non-volatile component.

The resin component constituting the pressure-sensitive adhesive composition is an acrylic resin containing a structural unit derived from the (meth)acrylic acid alkyl ester (P1) represented by the above formula (b) and the polar functional group-containing monomer (P2). It may include two or more types. Further, the acrylic resin (P) is mixed with a different acrylic resin, for example, an acrylic resin having a structural unit derived from the (meth)acrylic acid alkyl ester of the formula (b) and containing no polar functional group. You may use it. The acrylic resin (P) containing the structural unit derived from the (meth)acrylic acid alkyl ester (P1) represented by the formula (b) and the polar functional group-containing monomer (P2) is added to the total amount of the acrylic resin (P). On the other hand, it is preferably 80% by mass or more, and more preferably 90% by mass or more.

The acrylic resin (P), which is a copolymer of a monomer mixture containing the (meth)acrylic acid alkyl ester (P1) represented by the formula (b) and the polar functional group-containing monomer (P2), is a gel permeate. The weight average molecular weight Mw in terms of standard polystyrene measured by ion chromatography (GPC) is preferably in the range of 1,000,000 to 2,000,000. When the weight average molecular weight in terms of standard polystyrene is within the above range, the adhesiveness under high temperature and high humidity is improved, and the possibility of peeling or floating between the liquid crystal cell and the adhesive layer tends to be low, Further, the reworkability tends to be improved. Further, even if the size of the polarizing plate attached to the adhesive layer changes, the adhesive layer is likely to follow the dimensional change and fluctuate between the brightness of the peripheral portion of the liquid crystal cell and the brightness of the central portion. There is no difference between the two, and white spots and color unevenness tend to be suppressed.

The molecular weight distribution represented by the ratio Mw/Mn of the weight average molecular weight Mw and the number average molecular weight Mn is preferably in the range of 3 to 7. When the molecular weight distribution Mw/Mn is in the range of 3 to 7, occurrence of defects such as white spots can be suppressed even when the liquid crystal display panel or the liquid crystal display device is exposed to high temperature.

Further, the glass transition temperature of the acrylic resin (P) is preferably in the range of −10 to −60° C. from the viewpoint of exhibiting adhesiveness. The glass transition temperature of a resin can generally be measured by a differential scanning calorimeter.

The acrylic resin (P) constituting the pressure-sensitive adhesive composition can be produced by various known methods such as a solution polymerization method, an emulsion polymerization method, a bulk polymerization method and a suspension polymerization method. In the production of this acrylic resin, a polymerization initiator is usually used. The content of the polymerization initiator is preferably 0.001 to 5 parts by mass with respect to 100 parts by mass in total of all the monomers used for producing the acrylic resin.

As the polymerization initiator, a thermal polymerization initiator, a photopolymerization initiator or the like is used. Examples of the photopolymerization initiator include 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone. As the thermal polymerization initiator, for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis(2-methylbutyronitrile), 1,1′-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl-2,2'-azobis(2-methylpropio) And azo compounds such as 2,2′-azobis(2-hydroxymethylpropionitrile); lauryl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, tert-butyl peroxybenzoate, cumene hydroper. Organics such as oxides, diisopropyl peroxydicarbonate, dipropyl peroxydicarbonate, tert-butyl peroxy neodecanoate, tert-butyl peroxypivalate, and (3,5,5-trimethylhexanoyl)peroxide Peroxides: Inorganic peroxides such as potassium persulfate, ammonium persulfate, and hydrogen peroxide can be mentioned. Further, a redox type initiator in which a peroxide and a reducing agent are used in combination can also be used as the polymerization initiator.

A solution polymerization method is particularly preferable as the method for producing the acrylic resin (P). Explaining with a specific example of the solution polymerization method, a desired monomer and an organic solvent are mixed, a thermal polymerization initiator is added under a nitrogen atmosphere, and 40 to 90° C., preferably 50 to 80° C. A method of stirring for 10 hours can be mentioned. Further, in order to control the reaction, a monomer or a thermal polymerization initiator may be added continuously or intermittently during the polymerization, or may be added in a state of being dissolved in an organic solvent. Here, examples of the organic solvent include aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; aliphatic alcohols such as propyl alcohol and isopropyl alcohol; acetone, methyl ethyl ketone, and methyl isobutyl. Ketones such as ketones can be used.

The pressure-sensitive adhesive layer included in the polarizing plate of the present invention is preferably configured by using an acrylic resin (P) and a crosslinking agent in combination. The cross-linking agent that can be used is, for example, a compound that reacts with a structural unit derived from the polar functional group-containing monomer (P2) in the acrylic resin (P) to cross-link the acrylic resin. Specific examples include isocyanate compounds, epoxy compounds, aziridine compounds, metal chelate compounds, and the like. Among these, the isocyanate compound, the epoxy compound and the aziridine compound have at least two functional groups capable of reacting with the polar functional group in the acrylic resin (P) in the molecule.

The isocyanate compound is a compound having at least two isocyanato groups (-NCO) in the molecule, and examples thereof include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, Examples thereof include hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate and the like. Further, an adduct body obtained by reacting these isocyanate compounds with a polyol such as glycerol or trimethylolpropane, or a dimer or trimer of the isocyanate compound can also be a crosslinking agent used in the pressure-sensitive adhesive. .. It is also possible to use a mixture of two or more isocyanate compounds.

The epoxy compound is a compound having at least two epoxy groups in the molecule, and examples thereof include bisphenol A type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, and glycerin triglycidyl ether. , 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, N,N-diglycidyl aniline, N,N,N′,N′-tetraglycidyl-m-xylenediamine, 1,3-bis( N,N′-diglycidylaminomethyl)cyclohexane and the like can be mentioned. It is also possible to use a mixture of two or more epoxy compounds.

The aziridine-based compound is a compound having at least two 3-membered ring skeletons each having one nitrogen atom and two carbon atoms, which is also called ethyleneimine, in the molecule, and examples thereof include diphenylmethane-4,4′-bis. (1-aziridinecarboxamide), toluene-2,4-bis(1-aziridinecarboxamide), triethylenemelamine, isophthaloylbis-1-(2-methylaziridine), tris-1-aziridinylphosphine oxide, hexa Methylene-1,6-bis(1-aziridinecarboxamide), trimethylolpropane tris-β-aziridinylpropionate, tetramethylolmethane tris-β-aziridinylpropionate and the like can be mentioned.

As the metal chelate compound, for example, acetylacetone or ethyl acetoacetate is coordinated to a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium. A compound etc. are mentioned.

Among these cross-linking agents, isocyanate compounds, especially xylylene diisocyanate, tolylene diisocyanate or hexamethylene diisocyanate, or these isocyanate compounds, an adduct body obtained by reacting with a polyol such as glycerol or trimethylolpropane, A dimer or trimer of these isocyanate compounds and a mixture of these isocyanate compounds are preferably used. Especially when the polar functional group-containing monomer (P2) has a polar functional group selected from a free carboxyl group, a hydroxyl group, an amino group and an epoxy ring, it is preferable to use at least one isocyanate compound as a crosslinking agent. .. Among them, preferred isocyanate compounds include tolylene diisocyanate, adducts obtained by reacting tolylene diisocyanate with polyol, dimers of tolylene diisocyanate, and trimers of tolylene diisocyanate, and hexamethylene diisocyanate and hexamethylene diisocyanate. Examples thereof include an adduct body obtained by reacting with a polyol, a dimer of hexamethylene diisocyanate, and a trimer of hexamethylene diisocyanate.

In the pressure-sensitive adhesive layer constituting the polarizing plate of the present invention, the crosslinking agent is preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of the acrylic resin (P). The content of the cross-linking agent is more preferably 0.1 to 5 parts by mass, and still more preferably 0.2 to 3 parts by mass with respect to 100 parts by mass of the acrylic resin (P). When the amount of the cross-linking agent is within the above range, the durability of the pressure-sensitive adhesive layer tends to be improved, and the white spots on the liquid crystal display panel tend to be inconspicuous, which is preferable.

In the present invention, the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer preferably contains a silane-based compound, and particularly preferably, the silane-based compound is contained in the acrylic resin before the addition of the crosslinking agent. Since the silane-based compound improves the adhesive force to the glass, by including the silane-based compound, the adhesion between the liquid crystal cell sandwiched between the glass substrates and the adhesive layer is improved, and a high adhesive force to the display panel is ensured. You can

Examples of silane compounds include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, and N-(2-amino. Ethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl Trimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glyc Sidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropylethoxydimethylsilane and the like can be mentioned. These silane compounds may be used alone or in combination of two or more.

The silane compound may be of a silicone oligomer type. Examples of the silicone oligomer in the form of (monomer)-(monomer) copolymer include the following.
3-mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-mercaptopropyltriethoxysilane-tetramethoxysilane copolymer, and 3-mercaptopropyltriethoxysilane-tetraethoxy Copolymers containing mercaptopropyl groups, such as silane copolymers;
Mercaptomethyl, such as mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer, mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer, mercaptomethyltriethoxysilane-tetramethoxysilane copolymer, and mercaptomethyltriethoxysilane-tetraethoxysilane copolymer. Group-containing copolymers;
3-methacryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane -Tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, and Copolymers containing methacryloyloxypropyl groups, such as 3-methacryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymers;
3-acryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltriethoxysilane -Tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, and Copolymers containing acryloyloxypropyl groups, such as 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymers;
Vinyltrimethoxysilane-tetramethoxysilane copolymer, vinyltrimethoxysilane-tetraethoxysilane copolymer, vinyltriethoxysilane-tetramethoxysilane copolymer, vinyltriethoxysilane-tetraethoxysilane copolymer, vinylmethyldimethoxysilane-tetramethoxysilane copolymer, Copolymers containing vinyl groups, such as vinylmethyldimethoxysilane-tetraethoxysilane copolymers, vinylmethyldiethoxysilane-tetramethoxysilane copolymers, and vinylmethyldiethoxysilane-tetraethoxysilane copolymers;
3-aminopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetraethoxysilane Copolymer, 3-aminopropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-aminopropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-aminopropylmethyldiethoxysilane-tetramethoxysilane copolymer, and 3-aminopropylmethyldiethoxy Copolymers containing amino groups, such as silane-tetraethoxysilane copolymers.

These silane-based compounds are often liquids. The amount of the silane compound compounded in the pressure-sensitive adhesive is usually 0.01 to 10 parts by mass, preferably 100 parts by mass of the nonvolatile content of the acrylic resin (P) (the total amount when two or more types are used), and preferably The ratio is 0.03 to 1 part by mass. When the amount of the silane compound is 100% by mass of the nonvolatile content of the acrylic resin (P) within the above range, the adhesion between the adhesive layer and the liquid crystal cell is improved, and the bleeding of the silane compound from the adhesive layer is preferable. It is preferable because out tends to be suppressed.

In the present invention, the adhesive layer contains an ionic compound. Ionic compounds can function as antistatic agents. Particularly, when the acrylic resin (P) contains the aromatic ring-containing (meth)acrylic compound represented by the above formula (c) and n in the formula (c) is 2 or more, it is effective in suppressing white spots. Therefore, by blending an ionic compound into a pressure-sensitive adhesive containing an acrylic resin in which this monomer is copolymerized, it is possible to impart a good anti-whitening effect while also imparting good antistatic properties. The ionic compound as referred to herein is a compound that exists as a combination of a cation and an anion, and the cation and anion may be either inorganic or organic, but the acrylic resin (P) and From the viewpoint of compatibility, it is preferable that at least one of the cation and the anion is an ionic compound containing an organic group.

Examples of the inorganic cations constituting the ionic compound include lithium cations [Li ⁺ ], sodium cations [Na ⁺ ], potassium cations [K ⁺ ], cesium cations [Cs ⁺ ] and the like; beryllium cations [Be. ²⁺ ], magnesium cation [Mg ²⁺ ], calcium cation [Ca ²⁺ ], and other alkaline earth metal ions. Among them, from the viewpoint of metal corrosion resistance, it is preferable to use lithium cation [Li ⁺ ], potassium cation [K ⁺ ] or sodium cation [Na ⁺ ]. From the viewpoint of durability, potassium cation [K ⁺ ] is used. It is more preferable to use.

Examples of the organic cation constituting the ionic compound include a pyridinium-based cation represented by the following formula (d): and a quaternary ammonium cation represented by the following formula (e).

In formula (d), R _{5 to} R ₉ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R ₁₀ represents an alkyl group having 1 to 16 carbon atoms. In formula (e), R ₁₁ represents an alkyl group having 1 to 12 carbon atoms, and R ₁₂ , R ₁₃ and R ₁₄ each independently represent an alkyl group having 6 to 12 carbon atoms.

The pyridinium-based cation represented by the above formula (d) has a total carbon number of 6 or more, but among them, the total carbon number is 8 or more, and particularly 10 or more from the viewpoint of compatibility with the acrylic resin (P). Is preferred. The total number of carbon atoms is preferably 36 or less, more preferably 30 or less. Among the pyridinium cations represented by the formula (d), R ₇ bonded to the 4-position carbon atom of the pyridine ring is an alkyl group, and R ₅ , R ₆ and R bonded to other carbon atoms of the pyridine ring. _{One in which 8} and R ₉ are each a hydrogen atom is a preferred cation.

The following can be mentioned as specific examples of the pyridinium-based cation represented by the formula (d).
N-methyl-4-hexylpyridinium cation, N-butyl-4-methylpyridinium cation, N-butyl-2,4-diethylpyridinium cation, N-butyl-2-hexylpyridinium cation, N-hexyl-2-butylpyridinium Cation, N-hexyl-4-methylpyridinium cation, N-hexyl-4-ethylpyridinium cation, N-hexyl-4-butylpyridinium cation, N-octyl-4-methylpyridinium cation, N-octyl-4-ethylpyridinium Cation, N-octylpyridinium cation and the like.

The ammonium cation represented by the above formula (e) is a tetraalkylammonium cation, and the tetraalkylammonium cation has a total carbon number of 20 or more, further 22 or more. It is preferable from the viewpoint of solubility. The total number of carbon atoms is preferably 36 or less, more preferably 30 or less.

The following can be mentioned as specific examples of the tetraalkylammonium cation represented by the formula (e).
Tetrahexyl ammonium cation, tetraoctyl ammonium cation, tributyl methyl ammonium cation, trihexyl methyl ammonium cation, trioctyl methyl ammonium cation, tridecyl methyl ammonium cation, trihexyl ethyl ammonium cation, trioctyl ethyl ammonium cation and the like.

On the other hand, examples of the anion forming the ionic compound include the following.
Chloride anion [Cl ^-], bromide anion [Br ^-], iodide anion [I ^-], tetrachloro aluminate anion [AlCl ^4-] hepta-chloro-di aluminate anion _[Al 2 Cl ₇ ^-], tetrafluoroborate Anion [BF ₄ ⁻ ], hexafluorophosphate anion [PF ₆ ⁻ ], perchlorate anion [ClO ₄ ⁻ ], nitrate anion [NO ₃ ⁻ ], acetate anion [CH ₃ COO ⁻ ], trifluoroacetate anion [CF ₃ COO ⁻ ], methanesulfonate anion [CH ₃ SO ₃ ⁻ ], trifluoromethanesulfonate anion [CF ₃ SO ₃ ⁻ ], bis(trifluoromethanesulfonyl)imide anion [(CF ₃ SO ₂ ) ₂ N ⁻ ], tris(). trifluoromethanesulfonyl) meth acetonide anion _{[(CF 3 SO 2) 3 C} - ], hexafluoro ah cell anion [AsF ₆ ^-], hexafluoroantimonate anion [SbF ₆ ^-], hexafluoro niobate anions [NbF ₆ ^- ], hexafluoro tantalate anion [TaF ₆ ^-], (poly) hydrofluoroether fluoride anion [F _{(HF) n} ^-] (n is about 1 to 3), thiocyanate anion [SCN ^-], dicyanamide anion [( _CN) 2 N ^-], perfluorobutane sulfonate anion _[C 4 _F 9 SO ₃ ^-], bis (pentafluoroethane sulfonyl) imide anion _{[(C 2 F 5 SO 2)} 2 N - ], perfluoro butanoate Anion [C ₃ F ₇ COO ⁻ ], (trifluoromethanesulfonyl)(trifluoromethanecarbonyl)imide anion [(CF ₃ SO ₂ )(CF ₃ CO)N ⁻ ] and the like.

Specific examples of the ionic compound can be appropriately selected from the above-mentioned combination of cation and anion. Specific examples of ionic compounds that are combinations of cations and anions include the following.
Lithium bis(trifluoromethanesulfonyl)imide, lithium hexafluorophosphate, lithium iodide (lithium iodide), lithium bis(pentafluoroethanesulfonyl)imide, lithium tris(trifluoromethanesulfonyl)methanide, sodium bis(trifluoromethanesulfonyl)imide, Sodium bis(pentafluoroethanesulfonyl)imide, sodium tris(trifluoromethanesulfonyl)methanide, potassium bis(trifluoromethanesulfonyl)imide, potassium bis(pentafluoroethanesulfonyl)imide, potassium tris(trifluoromethanesulfonyl)methanide, N-methyl -4-hexylpyridinium bis(trifluoromethanesulfonyl)imide, N-butyl-2-methylpyridinium bis(trifluoromethanesulfonyl)imide, N-hexyl-4-methylpyridinium bis(trifluoromethanesulfonyl)imide, N-octyl-4 -Methylpyridinium bis(trifluoromethanesulfonyl)imide, N-methyl-4-hexylpyridinium hexafluorophosphate, N-butyl-2-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, N-octyl -4-Methylpyridinium hexafluorophosphate, N-methyl-4-hexylpyridinium perchlorate, N-butyl-2-methylpyridinium perchlorate, N-hexyl-4-methylpyridinium perchlorate, N-octyl-4-methylpyridinium Perchlorate, tetrahexylammonium bis(trifluoromethanesulfonyl)imide, tributylmethylammonium bis(trifluoromethanesulfonyl)imide, trihexylmethylammonium bis(trifluoromethanesulfonyl)imide, trioctylmethylammonium bis(trifluoromethanesulfonyl)imide, tetra Hexylammonium hexafluorophosphate, tributylmethylammonium hexafluorophosphate, trihexylmethylammonium hexafluorophosphate, trioctylmethylammonium hexafluorophosphate, tetrahexylammonium perchlorate, tributylmethylammonium pa -Chlorate, trihexylmethylammonium perchlorate, trioctylmethylammonium perchlorate, etc.

These ionic compounds may be used alone or in combination of two or more. Content of an ionic compound is 0.5-8 mass parts normally with respect to 100 mass parts of acrylic resins (P), Preferably it is 0.8-4 mass parts.

In the present invention, the adhesive layer may further contain a crosslinking catalyst, a weather resistance stabilizer, a tackifier, a plasticizer, a softening agent, a dye, a pigment, an inorganic filler, a resin other than an acrylic resin, and the like. It is also useful to add a UV-curable compound such as a polyfunctional acrylate and a photoinitiator to the pressure-sensitive adhesive, and irradiate and cure the UV-ray after forming the pressure-sensitive adhesive layer to obtain a harder pressure-sensitive adhesive layer. This embodies a second cross-linking structure in the pressure-sensitive adhesive and plays a role of improving durability such as heat resistance. Further, by using a crosslinking catalyst together with a crosslinking agent in the pressure-sensitive adhesive, the pressure-sensitive adhesive layer can be prepared by aging for a short time, and in the polarizing plate containing the obtained pressure-sensitive adhesive, floating between the polarizing plate and the pressure-sensitive adhesive layer may occur. Occurrence of peeling and foaming within the adhesive layer can be suppressed, and reworkability may be improved.

Examples of the crosslinking catalyst include amine compounds such as hexamethylenediamine, ethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethylenetetramine, isophoronediamine, trimethylenediamine, polyamino resin, and melamine resin. it can. When an amine compound is added to the adhesive as a crosslinking catalyst, an isocyanate compound is suitable as the crosslinking agent.

Furthermore, it is also possible to incorporate fine particles into the pressure-sensitive adhesive layer having a light-scattering property. Further, the adhesive layer may be blended with an antioxidant, an ultraviolet absorber or the like. Examples of the ultraviolet absorber include salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, nickel complex salt compounds and the like.

The pressure-sensitive adhesive layer is provided by a method in which the above-mentioned pressure-sensitive adhesive is used as an organic solvent solution and is applied onto a film or layer (for example, a polarizing film etc.) to be laminated with a die coater or a gravure coater and then dried. it can. It can also be provided by a method of transferring a sheet-like pressure-sensitive adhesive formed on a plastic film (referred to as a separate film) which has been subjected to a release treatment, to the film or layer to be laminated. The thickness of the adhesive layer is not particularly limited, but is preferably within the range of 2 to 40 μm, more preferably within the range of 5 to 35 μm, and further preferably within the range of 10 to 30 μm. ..

The adhesive layer preferably has a storage elastic modulus of 0.10 to 5.0 MPa at 23 to 80° C., more preferably 0.15 to 1.0 MPa. When the storage elastic modulus at 23 to 80° C. is 0.10 MPa or more, white spots due to contraction of the polarizing plate when the liquid crystal display panel with the polarizing plate attached to the liquid crystal cell is exposed to high temperature can be suppressed. Therefore, it is preferable. Further, when the pressure is 5 MPa or less, the durability is less likely to decrease due to the decrease in the adhesive force, which is preferable. Here, "showing a storage elastic modulus of 0.10 to 5.0 MPa at 23 to 80°C" means that the storage elastic modulus takes a value in the above range at any temperature in this range. Since the storage elastic modulus is gradually decreased with increasing temperature, if the storage elastic moduli at 23° C. and 80° C. are both within the above range, the adhesive layer has a storage elastic modulus within the above range at a temperature within this range. Can be seen as showing. The storage elastic modulus of the adhesive layer can be measured by a commercially available viscoelasticity measuring device, for example, a viscoelasticity measuring device "DYNAMIC ANALYZER RDA II" manufactured by REOMETRIC.

In a preferred embodiment, the pressure-sensitive adhesive layer of the polarizing plate of the present invention is an acrylic resin which is a copolymer of butyl acrylate, methyl acrylate, 2-hydroxyethyl acrylate, 2-phenoxyethyl acrylate and acrylic acid, silane. It is composed of a system compound, an isocyanate compound as a crosslinking agent, and an antistatic component.

[Polarizing film]
The polarizing film constituting the polarizing plate of the present invention is a film having a function of extracting linearly polarized light from incident natural light, and in the present invention, a polyvinyl alcohol-based resin film contains a dichroic dye and is adsorbed and oriented. It is a film. As the polyvinyl alcohol-based resin forming the polyvinyl alcohol-based resin film, a saponified polyvinyl acetate-based resin can be used. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and another monomer copolymerizable therewith (for example, ethylene-vinyl acetate copolymer). Coalescing). Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

The saponification degree of the polyvinyl alcohol-based resin is usually 85 to 100 mol %, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal modified with aldehydes, polyvinyl acetal, polyvinyl butyral and the like can be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually 1000 to 10000, preferably 1500 to 5000.

A film formed of such a polyvinyl alcohol-based resin can be used as a raw film of a polarizing film. The method for forming a film of the polyvinyl alcohol-based resin is not particularly limited, and the film can be formed by a conventionally known method. The thickness of the raw film made of a polyvinyl alcohol-based resin is not particularly limited, but considering the ease of stretching, it is, for example, 10 to 150 μm, preferably 15 to 100 μm, and more preferably It is 20 to 80 μm.

The polarizing film is usually a step of uniaxially stretching such a polyvinyl alcohol resin film, a step of adsorbing a dichroic dye by dyeing the polyvinyl alcohol resin film with a dichroic dye, It is manufactured through a step of treating the adsorbed polyvinyl alcohol resin film with a boric acid aqueous solution, and a step of washing with water after the treatment with the boric acid aqueous solution.

The uniaxial stretching of the polyvinyl alcohol-based resin film may be carried out before dyeing the dichroic dye, at the same time as dyeing, or after dyeing. When the uniaxial stretching is performed after dyeing, the uniaxial stretching may be performed before the boric acid treatment or during the boric acid treatment. It is also possible to carry out uniaxial stretching in these plural stages. In the uniaxial stretching, stretching may be uniaxial between rolls having different peripheral speeds, or uniaxial stretching may be performed using hot rolls. The uniaxial stretching may be dry stretching in which the stretching is performed in the atmosphere, or wet stretching in which the polyvinyl alcohol-based resin film is swollen with a solvent. From the viewpoint of suppressing the deformation of the polarizing film, the stretching ratio is preferably 8 times or less, more preferably 7.5 times or less, and further preferably 7 times or less. The stretching ratio is preferably 4.5 times or more from the viewpoint of exhibiting the function as a polarizing film.

Examples of the method of dyeing the polyvinyl alcohol-based resin film with the dichroic dye include a method of immersing the polyvinyl alcohol-based resin film in an aqueous solution containing the dichroic dye. As the dichroic pigment, for example, iodine or a dichroic dye is used. Examples of the dichroic dye include C.I. I. A dichroic direct dye composed of a disazo compound such as DIRECT RED 39 and a dichroic direct dye composed of a trisazo or tetrakisazo compound are included. The polyvinyl alcohol-based resin film is preferably immersed in water before the dyeing treatment.

When iodine is used as the dichroic dye, a method of immersing the polyvinyl alcohol resin film in an aqueous solution containing iodine and potassium iodide and dyeing is usually employed. The content of iodine in this aqueous solution is usually 0.01 to 1 part by mass per 100 parts by mass of water, and the content of potassium iodide is usually 0.5 to 20 parts by mass per 100 parts by mass of water. .. When iodine is used as the dichroic dye, the temperature of the aqueous solution used for dyeing is usually 20 to 40° C., and the immersion time (dyeing time) in this aqueous solution is usually 20 to 1800 seconds.

When a dichroic dye is used as the dichroic dye, a method of immersing the polyvinyl alcohol-based resin film in an aqueous solution containing the water-soluble dichroic dye and dyeing is usually employed. The content of the dichroic dye in this aqueous solution, usually, 1 × 10 ^-4 to 10 parts by weight per 100 parts by weight of water, preferably 1 × 10 ^-3 to 1 parts by weight, particularly preferably 1 × 10 ^{- 3} to 1×10 ^-2 parts by mass. This aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing aid. When a dichroic dye is used as the dichroic dye, the temperature of the dye aqueous solution used for dyeing is usually 20 to 80° C., and the immersion time (dyeing time) in this aqueous solution is usually 10 to 1800 seconds. is there.

The boric acid treatment after dyeing with the dichroic dye can be performed by immersing the dyed polyvinyl alcohol-based resin film in a boric acid-containing aqueous solution. The amount of boric acid in the boric acid-containing aqueous solution is usually 2 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. When iodine is used as the dichroic dye, this boric acid-containing aqueous solution preferably contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is usually 0.1 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. The immersion time in the boric acid-containing aqueous solution is usually 60 to 1200 seconds, preferably 150 to 600 seconds, more preferably 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually 50°C or higher, preferably 50 to 85°C, more preferably 60 to 80°C.

The polyvinyl alcohol-based resin film after the boric acid treatment is usually washed with water. The water washing treatment can be performed by, for example, immersing the boric acid-treated polyvinyl alcohol-based resin film in water. The temperature of water in the water washing treatment is usually 5 to 40°C, and the immersion time is usually 1 to 120 seconds. After washing with water, a drying process is performed to obtain a polarizing film. The drying treatment can be performed using a hot air dryer or a far infrared heater. The temperature of the drying treatment is usually 30 to 100°C, preferably 40 to 95°C, more preferably 50 to 90°C. The time for the drying treatment is usually 60 to 600 seconds, preferably 120 to 600 seconds.

Thus, the polyvinyl alcohol-based resin film is uniaxially stretched, dyed with a dichroic dye, and treated with boric acid to obtain a polarizing film. The thickness of the polarizing film can be, for example, 5 to 40 μm.

[Second cured material layer]
The polarizing plate of the present invention may have a second cured product layer composed of a cured product of a curable composition on the surface of the polarizing film opposite to the first cured product layer. The curable composition forming the cured product forming the second cured product layer may be the same as or different from the curable composition of the first cured product layer described above.

In one embodiment of the present invention, the second cured product layer also serves as an adhesive for adhering the polarizing film and the transparent protective film (5 in FIGS. 1 and 2) laminated on the side opposite to the liquid crystal cell. When the curable composition of the second cured product layer is different from the curable composition of the first cured product layer, the curable composition of the second cured product layer is known in the art because it functions. A photocurable adhesive can be used. Examples of the photocurable adhesive include a mixture of a photocurable epoxy resin and a photocationic polymerization initiator, and a mixture of a photocurable acrylic resin and a photoradical polymerization initiator. The curable composition that forms the cured product that constitutes the second cured product layer is appropriately selected according to the adhesiveness to the polarizing film and the second transparent protective film, and is described in, for example, WO 2014/129368 pamphlet. A photocurable adhesive containing a photocurable component and a photocationic polymerization initiator can be used.

In the present invention, the second cured material layer is formed by applying a curable composition (photocurable adhesive) to the surface of the polarizing plate opposite to the surface on which the first cured material layer is laminated, by a known method. It can be formed by For example, a casting method, a Mayer bar coating method, a gravure coating method, a comma coater method, a doctor blade method, a die coating method, a dip coating method, a spraying method and the like can be used. The casting method is a method in which an adhesive is flowed down and spread on the surface of a film to be coated while the film is moved in a substantially vertical direction, a substantially horizontal direction, or an oblique direction between the two. After the curable composition is applied, the polarizing film and the transparent protective film to be laminated thereon are overlapped and sandwiched by a nip roll or the like to laminate the films. For laminating a film using a nip roll, for example, a method of applying a curable composition and then uniformly pressing and spreading with a roll, a method of applying the curable composition, and then passing between the rolls Alternatively, a method of applying pressure and spreading can be adopted. In this case, the material of the roll used may be metal or rubber. When the film is passed between a plurality of rolls and spread, the plurality of rolls may be made of the same material or different materials.

When a photocurable adhesive is used, the photocurable adhesive is cured by irradiating with active energy rays. The light source of the active energy ray is not particularly limited, but an active energy ray having a light emission distribution at a wavelength of 400 nm or less is preferable, and specifically, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp. , A microwave-excited mercury lamp and a metal halide lamp are preferable.

The light irradiation intensity to the photocurable adhesive is appropriately determined depending on the composition of the photocurable adhesive and is not particularly limited, but the irradiation intensity in the wavelength region effective for activation of the polymerization initiator is preferably 0.1 to 10. It is 6000 mW/cm ² , more preferably 10 to 1000 mW/cm ² , and further preferably 20 to 500 mW/cm ² . When the irradiation intensity is within the above range, the reaction time can be ensured, and the yellowing of the epoxy resin and the deterioration of the polarizing film due to the heat radiated from the light source and the heat generated during the curing of the photocurable adhesive can be suppressed. You can The light irradiation time to the photocurable adhesive may be appropriately selected depending on the photocurable adhesive to be cured, and is not particularly limited, but the integrated light amount represented as the product of the irradiation intensity and the irradiation time. It is preferably 10 to 10000 mJ / ^{m 2,} more preferably 50~1000mJ / ^{m 2,} more preferably is set to be 80~500mJ / ^{m 2.} When the cumulative amount of light to the photocurable adhesive is within the above range, a sufficient amount of active species derived from the polymerization initiator can be generated to allow the curing reaction to proceed more reliably, and the irradiation time becomes longer. Good productivity can be maintained.

When the photocurable adhesive is cured by irradiation with active energy rays, for example, the polarization degree, the transmittance and the hue of the polarizing film, the transparency of various films constituting the transparent protective film and the optical layer, and the polarizing plate. It is preferable to carry out the curing under the condition that the various functions of (1) are not deteriorated. The thickness of the second cured product layer is not particularly limited, but is usually 0.1 to 10 μm.
[Transparent protective film]
In one embodiment, the polarizing plate of the present invention has a first transparent protective film (6 in Fig. 2) laminated on one surface of the polarizing film via a first cured material layer. Further, in one embodiment, the polarizing plate of the present invention has a second transparent protective film (5 in FIGS. 1 and 2) laminated on the other surface of the polarizing film via a second cured material layer. .. In one embodiment, the polarizing plate of the invention has a transparent protective film from the viewpoint of contributing to the prevention of shrinkage and expansion of the polarizing film and the prevention of deterioration of the polarizing film due to temperature, humidity, ultraviolet rays and the like. On the other hand, in one embodiment, from the viewpoint of thinning the polarizing plate, the polarizing plate of the present invention does not include the first transparent protective film.

As a material for forming the transparent protective film, a material having excellent transparency, mechanical strength, thermal stability, moisture shielding property, isotropy and the like is preferable. For example, polyester-based polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose, acrylic-based polymers such as polymethyl methacrylate, polystyrene and styrene such as acrylonitrile-styrene copolymer (AS resin). Examples thereof include a polymer and a polycarbonate polymer. Further, polyethylene, polypropylene, polyolefin having a cyclo-based or norbornene structure, polyolefin-based polymer such as ethylene/propylene copolymer, vinyl chloride-based polymer, amide-based polymer such as nylon or aromatic polyamide, imide-based polymer, sulfone-based Polymer, polyether sulfone-based polymer, polyether ether ketone-based polymer, polyphenylene sulfide-based polymer, vinyl alcohol-based polymer, vinylidene chloride-based polymer, vinyl butyral-based polymer, arylate-based polymer, polyoxymethylene-based polymer, epoxy-based polymer, or Blends of the above polymers may also be mentioned as examples of the polymer forming the transparent protective film. The transparent protective film can also be formed as a cured layer of a thermosetting or ultraviolet curable resin such as acrylic, urethane, acrylic urethane, epoxy, silicone or the like. Among them, those having a hydroxyl group having reactivity with an isocyanate crosslinking agent are preferable, and a cellulose polymer is particularly preferable.

In the polarizing plate of the present invention, the first transparent protective film and the second transparent protective film may be made of the same material or may be made of different materials.

The thickness of the transparent protective film is not particularly limited, but both the first transparent protective film and the second transparent protective film are generally 500 μm or less, preferably 1 to 300 μm, and preferably 5 to 200 μm. More preferably, it is more preferably 10 to 100 μm. Further, the transparent protective film may be composed of a transparent protective film having an optical compensation function added thereto.

In the polarizing plate of the present invention, since the first cured product layer can effectively suppress the movement of the ionic compound from the adhesive layer to the polarizing film, the material of the first transparent protective film constituting the polarizing plate is The selection range expands. That is, it is not necessary to use a transparent protective film that does not easily transmit an ionic compound, and a polarizing plate can be configured using a transparent protective film that easily transmits an ionic compound. As a result, the production cost can be reduced, and the polarizing plate of the present invention is advantageous from an industrial viewpoint.

Specifically, for example, it is immersed in a 50 mass% potassium iodide aqueous solution in an air atmosphere of 23° C. and 60% RH for 4.5 hours, taken out, washed with water in the air at 23° C. for 15 seconds, and then in the air at Use as the first transparent protective film a transparent protective film whose absorbance for light having a wavelength of 360 nm after treatment for 15 hours in the dark is preferably 5% or more higher than the absorbance before this treatment (initial absorbance). You can The increase in the absorbance after the above-mentioned treatment with respect to the initial absorbance may be 10% or more, or 15% or more, from the viewpoint of expanding the selection range for the material of the first transparent protective film. Further, the increase in the absorbance after the above treatment with respect to the initial absorbance is usually 25% or less.

The polarizing plate of the present invention may be further laminated with optical layers such as a retardation film, a viewing angle compensation film and a brightness enhancement film, if necessary. The optical layer in the polarizing plate of the present invention can be formed using a material known in the art.

The polarizing plate of the present invention can be manufactured by a known method. For example, a curable composition is applied to a transparent protective film to form a second curable composition layer, and a polarizing film is attached to the second curable composition layer to prepare a laminate. In the case of a polarizing plate that does not include the first transparent protective film, the curable composition is applied to the release film to form the first curable composition layer, and the polarizing film side of the laminate is attached to the coated surface. To do. Next, the second curable composition layer and the first curable composition layer are cured by irradiating with active energy rays such as ultraviolet rays and electron beams to form the second cured product layer and the first cured product layer. Then, the release film may be peeled off, and an adhesive layer may be formed on the first curable composition layer. On the other hand, in the case of a polarizing plate including a first transparent protective film, a curable composition is applied onto the transparent protective film to form a first cured product layer, and the polarizing film side of the laminate is attached to the coated surface. After that, the first cured product layer may be formed by irradiating with active energy rays such as ultraviolet rays and electron beams, and then the adhesive layer may be formed on the first transparent protective film.

The polarizing plate of the present invention can be used as a polarizing plate of an image display panel such as a liquid crystal panel or an organic EL panel. Since the polarizing plate of the present invention can suppress the deterioration of optical performance even in use under high temperature and high humidity environment and/or for a long period of time, it can be suitably used as a polarizing plate for an image display panel. The image display device including the polarizing plate of the present invention hardly causes a problem in image display performance.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. In addition, "%" and "parts" in Examples and Comparative Examples represent "mass%" and "parts by mass", respectively, unless otherwise specified.

1. Preparation of Laminate A By mixing the following polymerizable compounds (a-1), (a-2), (a-3) and (a-4) and a photocationic polymerization initiator (b-1), Curable composition a was prepared.
(A-1) 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate 25 parts by mass (a-2) neopentyl diglycidyl ether 55 parts by mass (a-3) glycidyl methacrylate 25 parts, methyl methacrylate 75 Polymer having a weight average molecular weight of 15,000 obtained by radically polymerizing a monomer composed of 10 parts (GMA-PMMA (polymethylmethacrylate) copolymer) 15 parts by mass (a-4) hydroxybutyl vinyl ether 5 parts by mass (b-1) Triarylsulfonium hexafluorophosphate 2.25 parts by mass

Corona discharge treatment is applied to the surface of acrylic resin (PMMA) film [trade name "Technoloy S001", manufactured by Sumitomo Chemical Co., Ltd.] (second transparent protective film) with a thickness of 60 μm containing an ultraviolet absorber, and the corona discharge treatment is performed. The curable composition a was applied to the surface by using a bar coater so that the film thickness after curing was about 3 μm to form a layer of the curable composition a. A 25 μm thick polyvinyl alcohol (PVA)-iodine based polarizing film was attached to this layer to form a laminate. From the polarizing film side of this laminate, ultraviolet rays were irradiated using an ultraviolet irradiation device with a belt conveyor [lamp: "D bulb" manufactured by Fusion UV Systems Co., Ltd.] so that the integrated light amount at a wavelength of 280 nm to 320 nm would be 200 mJ/cm ^2. The curable composition a was cured by irradiation to produce a laminate A composed of an acrylic resin film (second transparent protective film)/second cured product layer/polarizing film.

2. Preparation of pressure-sensitive adhesive composition An acrylic pressure-sensitive adhesive was prepared as follows.
To butyl acrylate 70.4 parts by mass, methyl acrylate 20.0 parts by mass, acrylic acid 0.6 parts by mass, 2-phenoxyethyl acrylate 8.0 parts by mass and 2-hydroxyethyl acrylate 1.0 part by mass. On the other hand, 0.14 of azobisisobutyronitrile, which is a polymerization initiator, was added to carry out a polymerization reaction to prepare an acrylic resin. An isocyanate-based crosslinking agent (Coronate L: a solution of trimethylolpropane adduct of tolylene diisocyanate in ethyl acetate (solid content concentration: 75%)) based on 20.0 parts by mass of the acrylic resin, manufactured by Nippon Polyurethane Co., Ltd. ) 0.45 parts by mass, silane coupling agent (KBM-403: 3-glycidoxypropyltrimethoxysilane (liquid), manufactured by Shin-Etsu Chemical Co., Ltd.) 0.45 parts by mass, and antistatic agent (1- Hexylpyridinium hexafluorophosphate (a compound represented by the following formula (f)) (3.0 parts by mass) was added to prepare an organic solvent solution of an acrylic resin pressure-sensitive adhesive.

[Example 1]
First, each polymerizable compound shown in Table 1 and the cationic photopolymerization initiator (b-1) were mixed in the respective amounts used to prepare a curable composition b. Next, corona discharge treatment was performed on one surface of a cellulose-based transparent protective film having a thickness of 34 μm [Fuji Film Co., Ltd. “ZRE34”], and the curable composition b was cured on that surface using a bar coater. The coating was performed so that the film thickness was about 3 μm. The laminate A was attached to the coated surface on the polarizing film side to prepare a laminate. From the cellulose-based transparent protective film side of this laminate, an integrated light amount of wavelength 280 nm to 320 nm is 200 mJ/cm ² using an ultraviolet irradiation device with a belt conveyor [lamp: "D bulb" manufactured by Fusion UV Systems, Inc.]. The curable composition b was cured by irradiating the composition with ultraviolet rays. Thus, a laminate B composed of the acrylic resin film (second transparent protective film)/second cured product layer/polarizing film/first cured product layer/cellulosic transparent protective film (first transparent protective film) was produced.

A 38 μm thick polyethylene terephthalate film [trade name “SP-PLR382050”, manufactured by Lintec Co., Ltd. (hereinafter, referred to as “release film”)] was prepared by subjecting an organic solvent solution of the acrylic resin adhesive to a release treatment. The release-treated surface was coated with a die coater so that the thickness after drying was 20 μm, and dried to prepare a sheet-like pressure-sensitive adhesive with a release film. After that, the surface of the sheet-shaped pressure-sensitive adhesive opposite to the release film side (pressure-sensitive adhesive surface) was attached to the cellulose-based transparent protective film (first transparent protective film) side of the laminate B by a laminator, and then the temperature was changed. After curing at 23° C. and 65% relative humidity for 7 days, a polarizing plate (1) provided with an adhesive layer was obtained. This polarizing plate has a structure in which a release film is laminated on an adhesive layer.

Durability Evaluation The obtained polarizing plate (1) was cut into a size of 30 mm×30 mm, the release film was peeled off, and the adhesive layer side was bonded to non-alkali glass [trade name “EAGLE XG” manufactured by Corning Incorporated]. did. The durability of the obtained sample was evaluated as follows.

The sample was autoclaved at a temperature of 50° C. and a pressure of 5 kg/cm ² (490.3 kPa) for 1 hour, and then kept in an environment of a temperature of 23° C. and a relative humidity of 55% for 24 hours. About this sample, set the UV-Visible spectrophotometer (UV2450, Shimadzu Corporation) with the optional film holder "with polarizing film" and set the transmission axis direction and absorption of the polarizing plate in the wavelength range of 380 to 700 nm. The transmission spectrum in the axial direction was measured, and the polarization degree Py (unit: %) was determined based on the measured transmission spectra. The degree of polarization in this state was defined as the initial degree of polarization (Py after the test). Then, the post-test polarization degree (initial Py) was determined in the same manner as above for the sample after standing for 12 hours in an environment of 85° C. and relative humidity of 85%. The polarization degree change ΔPy was calculated from the following formula, using the optical performance as an initial value before standing for 12 hours in an environment of 85° C. and relative humidity of 85%. The results are shown in Table 1.
ΔPy=Py after test−Initial Py

The absorbance of the cellulose-based transparent protective film [trade name "ZRE34" manufactured by Fuji Film Co., Ltd.] for light having a wavelength of 360 nm was measured using an ultraviolet-visible spectrophotometer [Shimadzu Corporation "UV2450"]. The absorbance was used as the initial absorbance. Next, this film was immersed in a 50 mass% potassium iodide aqueous solution in an atmosphere of 23° C. and 60% RH for 4.5 hours, taken out, washed with water at 23° C. in the dark at 23° C. in the dark. And dried for 15 hours. When the film after this treatment was measured for absorbance at light having a wavelength of 360 nm, it was found to be 22% higher than the initial absorbance.

[Examples 2 to 10]
Instead of the curable composition b, a curable composition prepared by mixing each compound described in Table 1 in each amount used was used in the same manner as in Example 1 except that the acrylic resin film (first (2 transparent protective film)/second cured product layer/polarizing film/first cured product layer/cellulosic transparent protective film (first transparent protective film).

Next, an adhesive layer was provided in the same manner as in Example 1 to obtain polarizing plates (2) to (10), respectively. The durability of each of the polarizing plates (2) to (10) was evaluated. The results are shown in Table 1.

[Comparative Example 1]
A polarizing plate (11) was prepared in the same manner as in Example 1 except that the curable composition d was prepared by mixing the respective compounds described in Table 1 in the respective amounts used and coating the composition on the cellulose-based transparent protective film. Got The durability of this polarizing plate (11) was evaluated. The results are shown in Table 1.

[Comparative Examples 2 to 7]
A polarizing plate (12) was prepared in the same manner as in Example 1, except that the curable composition e was prepared by mixing the respective compounds described in Table 1 in the respective amounts used and coating the composition on a cellulose-based transparent protective film. ~ (17) was obtained. The durability of each of the polarizing plates (12) to (17) was evaluated. The results are shown in Table 1.

The compounds in Table 1 are as follows.
-Oxetane compound (bifunctional): bis(3-ethyl-3-oxetanylmethyl) ether (Toagosei Co., Ltd.)
-Aliphatic epoxy compound (1): 1,4-butanediol diglycidyl ether (EX214, Nagase Chemtex Co., Ltd.)
Aliphatic epoxy compound (2): 1,6-hexanediol diglycidyl ether (EX212, Nagase Chemtex Co., Ltd.)
-Aliphatic epoxy compound (3): neopentyl glycol diglycidyl ether (EX211, Nagase Chemtex Co., Ltd.)
Aliphatic epoxy compound (4): cyclohexanedimethanol diglycidyl ether (EX216, Nagase Chemtex Co., Ltd.)
-Aliphatic epoxy compound (5): pentaerythritol polyglycidyl ether (EX411, Nagase Chemtex Co., Ltd.)
-Alicyclic epoxy compound: 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (CEL2021P, Daicel Chemical Industries, Ltd.)
-Aromatic epoxy compound (1): 2-[4-(2,3-epoxypropoxy)phenyl]-2-[4-[1,1-bis[4-([2,3-epoxypropoxy]phenyl]) Ethyl]phenyl]propane (TECHMORE VG3101L, Printec Co., Ltd.)
-Aromatic epoxy compound (2): resorcinol diglycidyl ether (EX-201, Nagase Chemtex Co., Ltd.)
-Aromatic epoxy compound (3): Bis F type epoxy (jER806, Mitsubishi Chemical Corporation)
-Aromatic epoxy compound (4): p-tert-butylphenyl glycidyl ether (EX-146, Nagase Chemtex Co., Ltd.)
-Aliphatic epoxy compound: 2-ethylhexyl glycidyl ether (EX121, Nagase Chemtex Co., Ltd.)
-Oxetane compound (monofunctional): 3-ethyl-3-hydroxymethyl oxetane (OXT101, Toagosei Co., Ltd.)
Photo-cationic polymerization initiator (b-1): triarylsulfonium hexafluorophosphate

It can be seen from Table 1 that the polarizing plates (1) to (10) obtained in Examples 1 to 10 have a small change in polarization degree ΔPy, and therefore show no significant change in optical performance and exhibit high durability. On the other hand, in all of the polarizing plates (11) to (17) obtained in Comparative Examples 1 to 7, the change in polarization degree ΔPy was large, and the deterioration of the optical performance was observed.

1: Polarizing film 2: First cured material layer 3: Adhesive layer 4: Second cured material layer 5: Second transparent protective film 6: First transparent protective film 10: Polarizing plate X: Liquid crystal cell

Claims (3)

A first cured product layer composed of a cured product of a curable composition containing a polymerizable compound and an ionic compound are provided on one surface of a polarizing film containing a dichroic dye in a polyvinyl alcohol resin. A polarizing plate containing an adhesive layer in this order, wherein the curable composition is
(A1) containing an oxetane compound having two or more oxetanyl groups, and (A2) an aliphatic epoxy compound having two or more epoxy groups,
The curable composition, relative to the total amount of the polymerizable compound 100 mass%,
(A1) 15 to 70 mass%, and (A2) 3 to 40 mass%
Containing
A polarizing plate in which the content of the oxetane compound (A3) having one oxetanyl group is 10% by mass or less based on 100% by mass of the total amount of the polymerizable compounds. A first transparent protective film is provided between the first cured product layer and the adhesive layer, and the first transparent protective film is a 4 wt% aqueous solution of potassium iodide at 23° C. and 60% RH in an air atmosphere. Soak for 5 hours, take out, rinse with water at 23°C for 15 seconds in the air, and dry for 15 hours in the dark at 23°C in the air. The polarizing plate according to claim 1, which is 5% or more higher than the polarizing plate. The polarizing plate according to claim 1, wherein a second transparent protective film is provided on a surface of the polarizing film opposite to the first cured material layer side with a second cured material layer interposed therebetween.