KR20170041634A - Polarizing plate - Google Patents

Abstract

The present invention provides a polarizing plate which can suppress deterioration of optical performance over time and thus has high durability. The polarizing plate has a first cured substance layer, made of a cured substance of a curable composition comprising a polymerizable compound, and the adhesive layer in order on one side of the polarizing film containing dichroic pigments in polyvinyl alcohol resin. The curable composition contains an oxetane compound (A1) having two or more oxetanyl groups and an aliphatic epoxy compound (A2) having two or more epoxy groups. The curable compound contains 15-70 mass% of (A1) and 3-40 mass% of (A2) with respect to total 100 mass% of the polymerizable compound. Content of an oxetane compound (A3) having one oxetanyl group is 10 mass% or smaller with respect to total 100 mass% of the polymerizable compound.

Description

POLARIZING PLATE

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

BACKGROUND ART Conventionally, a polarizing plate has been used in various image display panels such as a liquid crystal display panel and an organic electroluminescence (organic EL) display panel by being bonded to an image display device such as a liquid crystal cell or an organic EL display device. As such a polarizing plate, a protective film such as a triacetylcellulose film is laminated on one or both sides 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 through an adhesive layer (For example, Patent Document 1). Such a polarizing plate may be formed by laminating various optical layers such as a retardation film or an optical compensation film, if necessary, to an image display element such as a liquid crystal cell or an organic EL display element through a pressure-sensitive adhesive, do.

Patent Document 1: Japanese Patent Application Laid-Open Publication No. 2012-208250

When static electricity is charged on the image display panel, a problem arises in the display function. Therefore, there is a case where electrification of the static electricity is prevented by mixing an antistatic agent with the polarizing plate. For example, an antistatic agent may be blended in the adhesive layer in the polarizing plate. In this case, the optical performance of the polarizing plate may deteriorate over time in the use for a long time and / or under a high temperature and high humidity environment. It is considered 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, and therefore the polarization property is lowered. In such a polarizing plate in which the optical performance is deteriorated, there is a fear that the image display performance is lowered.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve the problems inherent in a polarizing plate having an antistatic function, and to provide a polarizing plate capable of suppressing deterioration of optical performance over time and having high durability.

The present invention provides the following preferred embodiments [1] to [4].

[1] A polarizing plate comprising a polarizing film containing a dichroic dye in a polyvinyl alcohol-based resin, a first cured layer composed of a cured product of a curable composition containing a polymerizable compound, And a pressure-sensitive adhesive layer in this order, wherein the polymerizable compound is a polymerizable compound,

(A1) an oxetane compound having at least two oxetanyl groups, and

(A2) an aliphatic epoxy compound having two or more epoxy groups

≪ / RTI >

The curable composition preferably contains, relative to 100 mass% of the total amount of the polymerizable compound,

(A1) of 15 to 70 mass%, and

(A2) 3 to 40 mass%

≪ / RTI >

Wherein the content of the oxetane compound (A3) having one oxetanyl group is 10 mass% or less based on 100 mass% of the total amount of the polymerizable compound.

[2] a first transparent protective film between the first cured layer and the adhesive layer, wherein the first transparent protective film is immersed in an aqueous solution of 50 mass% potassium iodide for 4.5 hours in an atmosphere of 23 ° C and 60% The absorbance with respect to the light having a wavelength of 360 nm after washing with water at 23 캜 for 15 seconds in the atmosphere and drying in a dark place at 23 캜 for 15 hours is not less than 5% Polarizer according to [1] above.

[3] The polarizing plate described in [1] or [2], wherein a second transparent protective film is provided on a surface of the polarizing film opposite to the first cured layer side through a second cured layer.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to suppress deterioration of optical performance over time and to provide a polarizer having high durability.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a cross-sectional view showing the constitution of an embodiment of a polarizing plate construction. Fig.
Fig. 2 shows a cross-sectional view showing the configuration of an embodiment of a polarizing plate structure.

A polarizing plate of the present invention is a polarizing plate comprising a polarizing film containing a dichroic dye in a polyvinyl alcohol resin, a first cured layer composed of a cured product of a curable composition containing a polymerizable compound, And a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive layer 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, but can be modified in various ways 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 with reference to Fig. The polarizing plate 10 of the present invention has a structure in which the first cured layer 2 and the adhesive layer 3 are laminated on one side of the polarizing film 1 in this order. The second transparent protective film 5 may be provided on the surface of the polarizing film 1 opposite to the first cured layer side through the second cured layer 4 as required.

The polarizing plate 10 of the present invention has a structure in which a first cured layer 2 and an adhesive layer 3 are laminated in this order on one surface of a polarizing film 1, The first transparent protective film 6 may be provided between the adhesive layer 2 and the adhesive layer 3. This embodiment is shown in Fig.

Although the polarizing plate 10 is provided with the second transparent protective film 5 on the surface opposite to the first cured layer of the polarizing film 1 through the second cured layer 4 good.

The polarizing plate 10 of the present invention is disposed on one surface of the liquid crystal cell X through the adhesive layer and a polarizing plate identical or different from the polarizing plate of the present invention is placed on the other surface of the liquid crystal cell Thereby constituting a liquid crystal display panel.

Hereinafter, each component of the polarizing plate of the present invention will be described in detail.

[First cured layer]

The polarizing plate of the present invention contains a first cured layer on one side of the polarizing film. Wherein the first cured layer is composed of a cured product of a curable composition comprising a polymerizable compound,

(A1) an oxetane compound having at least two oxetanyl groups, and

(A2) an aliphatic epoxy compound having two or more epoxy groups

Lt; / RTI >

(A1) An oxetane compound having two or more oxetanyl groups (hereinafter occasionally referred to as "oxetane compound (A1)") is a compound having two or more oxetanyl groups (oxetanyl groups) in the molecule. The oxetane compound (A1) may be aliphatic, alicyclic or aromatic. Examples of the oxetane compound (A1) include 1,4-bis [{(3-ethyloxetan-3-yl) methoxy} methyl] benzene (also referred to as xylylene bisoxetane) Ethyl-3-oxycetanylmethyl) ether, and the like. These oxetane compounds (A1) may be used either individually or in combination of two or more. By containing the oxetane compound (A1) having two or more oxetanyl groups as the polymerizable compound, the curable composition is cured to obtain a dense cured product because the crosslinking density is high. Therefore, it is possible to effectively suppress the movement of the ionic compound from the adhesive layer by forming a cured layer composed of such a cured product between the polarizing film and the adhesive layer.

The aliphatic epoxy compound (A2) having two or more epoxy groups (hereinafter sometimes referred to as "aliphatic epoxy compound (A2)") is a compound having at least two epoxy rings bonded to aliphatic carbon atoms in the molecule. 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; Trifunctional or higher epoxy compounds such as trimethylolpropane triglycidyl ether and pentaerythritol tetraglycidyl ether; 4-vinylcyclohexene dioxide, limonene dioxide, and the like, and an epoxy compound having an oxirane ring bonded to an aliphatic carbon atom. The aliphatic epoxy compound (A2) may be used alone or in combination of two or more different species.

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

In formula (I), Z represents an alkylene group having 1 to 9 carbon atoms, an alkylidene group having 3 or 4 carbon atoms, a divalent alicyclic hydrocarbon group, or a group represented by the formula -C _m H _2m -Z ¹ -C _n H _2n - Lt; / RTI > In the formula -C _m H _2m -Z ¹ -C _n H _2n -, -Z ¹ - represents -O-, -CO-O-, -O-CO-, -SO ₂ -, -SO- or -CO-, 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 includes a divalent group represented by the following formula (I-1).

Specific examples of the aliphatic diepoxy compound represented by the formula (I) include diglycidyl ether of an alkanediol, diglycidyl ether of an oligoalkylene glycol having up to about 4 repeating units, or diglycidyl ether of an alicyclic diol It is a sidyl ether.

Examples of the diol (glycol) capable of forming the aliphatic diepoxy compound represented by the formula (I) include ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, Propanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-2,4-pentanediol, 2,4-pentanediol, Methyl-2,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 3,5 Alkane diols such as heptane diol, 1,8-octane diol, 2-methyl-1,8-octane diol and 1,9-nonane diol;

Oligoalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol and dipropylene glycol;

Alicyclic diols such as cyclohexanediol, cyclohexanedimethanol, and the like.

In the present invention, the aliphatic diepoxy compound represented by the formula (I) is preferably a 1,4-butanediol diglycidyl ether, a 1,6-hexane Diol diglycidyl ether, and neopentyl glycol diglycidyl ether are preferable. 1,6-hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, and pentaerythritol polyglycidyl ether are preferable from the standpoint of maintaining optical performance. The aliphatic diepoxy compounds may be used alone or in combination of two or more different species.

In the present invention, the curable composition preferably contains 15 to 70 mass%, preferably 35 to 60 mass%, and more preferably 45 to 55 mass% of the oxetane compound ( A1). When the content of the oxetane compound (A1) in the curable composition is not lower than the lower limit described above, the movement of the ionic compound can be sufficiently suppressed. When the content of the oxetane compound (A1) in the curable composition is not more than the upper limit, the curing proceeds rapidly, and a cured layer having sufficient hardness can be easily formed.

When the curable composition contains the aliphatic epoxy compound (A2), the curable composition is preferably contained in an amount of 3 to 40 mass%, preferably 5 to 25 mass%, more preferably 5 to 20 mass%, based on 100 mass% And 5 to 15% by mass of an aliphatic epoxy compound (A2). When the content of the aliphatic epoxy compound (A2) in the curable composition is at least the lower limit value, a composition which is easy to apply can be obtained since the viscosity is low. When the content of the aliphatic epoxy compound (A2) in the curable composition is not more than the above-mentioned upper limit value, the elasticity of the cured product after curing is not excessively low, and cracking due to heat shrinkage of the polarizing film can be suppressed.

The curable composition may contain an oxetane compound (A3) having one oxetanyl group. The content of the oxetane compound (A3) having one oxetanyl group is 10 mass% or less, preferably 5 mass% or less, and 0 mass%, based on 100 mass% of the total amount of the polymerizable compound. When the content of the oxetane compound (A3) having one oxetanyl group is not more than the upper limit, the crosslinking 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). As the compound (A4) having two or more epoxy groups, an alicyclic epoxy compound (A4-1) having two or more epoxy groups (hereinafter sometimes referred to as "alicyclic epoxy compound (A4-1)") and 2 (Hereinafter sometimes referred to as " aromatic epoxy compound (A4-2) ") having at least one epoxy group.

The alicyclic epoxy compound (A4-1) is a compound having two or more epoxy groups bonded to an alicyclic ring in a molecule. The "epoxy group bonded to the alicyclic ring" means an epoxy group bonded to an alicyclic ring represented by the following formula (a):

Means the bridging oxygen atom -O- in the structure represented by the formula (1). In the above formula (a), m is an integer of 2 to 5.

A compound in which at least one group of two or more hydrogen atoms removed from (CH ₂ ) _m in the formula (a) is bonded to another chemical structure is referred to as an alicyclic epoxy compound (A4-1) . (CH ₂ ) _m may be suitably substituted with a straight chain 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 two or more different species.

Among them, from the viewpoint that the cured product has a high glass transition temperature and is excellent in adhesion between the polarizing film and the transparent protective film, an epoxy cyclopentane structure [in which m = 3 in the formula (a)] and an epoxycyclo An alicyclic epoxy compound having a hexane structure [wherein m = 4 in the formula (a)] is preferable, and an alicyclic diepoxy compound represented by the following formula (II) is more preferable. Particularly, since the curable composition contains an aliphatic diepoxy compound represented by the following formula (II), the cured layer after curing of the curable composition has high elasticity and can suppress cracking due to heat shrinkage of the polarizing film.

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 straight chain 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 the formula (II), X represents an oxygen atom, an alkanediyl group having 1 to 6 carbon atoms, or a group represented by the following formulas (IIa) to (IId):

Or a divalent group represented by any of the following formulas.

Examples of the alkanediyl group having 1 to 6 carbon atoms include a methylene group, an ethylene group and a propane-1,2-diyl group.

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

As the alicyclic diepoxy compound, for example, the following compounds A to M can be mentioned. In addition, the formulas A to M described hereinafter correspond to the compounds A to M, respectively.

A: 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 3,4-

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-epoxycyclohexylmethyl ether),

G: ethylene glycol bis (3,4-epoxycyclohexylmethyl ether),

H: 2,3,14,15-diepoxy-7,11,18,21-tetraoxatrispyro [5.2.2.5.2.2] hexocycline,

I: 3- (3,4-epoxycyclohexyl) -8,9-epoxy-1,5-dioxaspiro [5.5] undecane,

J: 4-vinylcyclohexene dioxide,

K: limonene dioxide,

L: bis (2,3-epoxycyclopentyl) ether,

M: dicyclopentadiene dioxide.

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

The aromatic epoxy compound (A4-2) is a compound having two or more epoxy groups and having at least one aromatic ring. Examples of the aromatic epoxy compound (A4-2) include the following.

Glycidyl ether compounds or epoxy novolac resins of bisphenol A, bisphenol F, or compounds having additionally alkylene oxide added thereto;

Glycidyl ethers of aromatic compounds having at least two phenolic hydroxyl groups such as resorcinol, hydroquinone and catechol;

Glycidyl ether compounds of aromatic compounds having two or more alcoholic hydroxyl groups such as benzene dimethanol, benzene diethanol and benzene dibutanol;

Glycidyl esters of polybasic acid aromatic compounds having two or more carboxylic acids such as phthalic acid, terephthalic acid and trimellitic acid;

Glycidyl esters of benzoic acids such as benzoic acid, toluene acid and naphthoic acid;

Styrene oxide or epoxides of divinylbenzene.

The aromatic epoxy compound (A4-2) may be used alone or in combination of two or more different kinds.

Among them, from the viewpoint of low viscosity of the curable composition, glycidyl ether compounds of an aromatic compound having two or more alcoholic hydroxyl groups, glycidyl ether compounds of polyhydric phenols, glycidyl esters of benzoic acids, glycidyl And at least one member selected from the group of epoxides of dicarboxylic acid, diester ester, styrene oxide or divinylbenzene.

In order to improve the curability of the curable composition, the aromatic epoxy compound (A4-2) preferably has an epoxy equivalent of 80 to 500. The aromatic epoxy compound (A4-2) may be used alone or in combination of two or more different kinds.

In a preferred embodiment of the present invention, the curable resin composition comprises the aliphatic diepoxy compound represented by the formula (I) and the alicyclic diepoxy compound represented by the formula (II). In this case, since the crosslinked density is high and a dense cured layer can be obtained, the migration 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 layer can be formed, and movement 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% by mass, more preferably 25 to 60% by mass, based on 100% by mass of the total amount of the polymerizable compound By mass, more preferably 25 to 50% by mass, of an alicyclic epoxy compound (A4-1). When the content of the alicyclic epoxy compound (A4-1) in the curable composition is within the above range, the curing by the irradiation of the active energy ray proceeds rapidly, and a cured layer of sufficient hardness can be easily formed.

When the curable composition contains an aromatic epoxy compound (A4-2), the curable composition is preferably contained in an amount of 0.1 to 20% by mass, more preferably 5 to 20% by mass based on 100% by mass of the total amount of the polymerizable compound % Of aromatic epoxy compound (A4-2). If the content of the aromatic epoxy compound (A4-2) in the curable composition is not lower than the lower limit value described above, the cured product tends to become 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 not more than the upper limit, adhesion with the polarizing film is good.

The curable composition may contain another polymerizable compound (A5) different from the polymerizable compounds (A1) to (A4). Examples of the other polymerizable compound (A5) include monoepoxy compounds and the like. 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 the polymerizable compound, the content thereof is preferably 10% by mass or less based on 100% by mass of the total of the polymerizable compounds (A1) to (A5) contained in the curable composition And more preferably 5% by mass or less.

The curable composition usually contains a polymerization initiator for initiating polymerization. As the polymerization initiator, for example, a photocationic polymerization initiator (B) can be mentioned. The cationic ionic polymerization initiator generates a cationic species or a Lewis acid by irradiation of an active energy ray such as visible light, ultraviolet ray, X-ray or electron beam to initiate the polymerization reaction of the cationic polymerizable compound. Since the photocationic polymerization initiator acts catalytically with light, it is excellent in storage stability and workability even when mixed with a photopolymerizable compound. Examples of the compound capable of generating a cationic species or Lewis acid by irradiation with an active energy ray include an onium salt such as an aromatic iodonium salt and an aromatic sulfonium salt, an aromatic diazonium salt, and an iron-arene complex.

The aromatic iodonium salt is a compound having a diaryl iodonium cation, and as this cation, a diphenyl iodonium cation is typically exemplified.

The aromatic sulfonium salt is a compound having a triarylsulfonium cation. Typical examples of the cation include a triphenylsulfonium cation and a 4,4'-bis (diphenylsulfonium) diphenylsulfide cation. have. The aromatic diazonium salt is a compound having a diazonium cation, and as the cation, a benzene diazonium cation is typically exemplified. In addition, the iron-arene complex is typically a cyclopentadienyl iron (II) arene cation complex.

The cations described above are paired with anions (anions) to form a cationic ion polymerization initiator. Examples of anions constituting the photocationic polymerization initiator include special phosphorus anion [(Rf) _n PF _6-n ] ^- , hexafluorophosphate anion PF ₆ ^- , hexafluoroantimonate anion SbF ₆ ^- , pentafluoro by hydroxy antimonate anion SbF ₅ (OH) ^-, hexafluoro-acetoxy anion AsF ₆ ^-, anion as tetrafluoroborate BF ₄ ^-, tetrakis (pentafluorophenyl) borate anion B (C ₆ F _{5) 4} ^- and so on. Among them, a special phosphorus anion [(Rf) _n PF _{6 -n} ] ^- and a hexafluorophosphate anion PF ₆ ^- are preferable from the viewpoints of the curability of the cationic polymerizable compound and the safety of the resulting cured layer.

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

The blending amount of the photocationic polymerization initiator (B) is generally 0.5 to 10 parts by mass, preferably 6 parts by mass or less, based on 100 parts by mass of the polymerizable compound. By blending at least 0.5 part by mass of the cationic ion polymerization initiator (B), the polymerizable compound can be sufficiently cured, and a high mechanical strength and adhesive strength can be imparted to the cured layer composed of the obtained cured product. 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 constituting the polarizing film, thereby deteriorating the optical performance of the polarizing film.

In the present invention, the curable composition may include additives commonly used in the curable composition, if necessary. Examples of such an additive include an ion trapping agent, an antioxidant, a chain transfer agent, a polymerization promoter (polyol and the like), a sensitizer, a sensitizer, a light stabilizer, a light stabilizer, a tackifier, a thermoplastic resin, a filler, A leveling agent, a silane coupling agent, a dye, an antistatic agent, and an ultraviolet absorber.

The photosensitizer is a compound that exhibits maximum absorption at a wavelength longer than the maximum absorption wavelength at which the cationic ionic polymerization initiator (B) is visible and promotes the polymerization initiation reaction by the cationic ionic polymerization initiator (B).

The photosensitizing assistant is a compound that further promotes the action of the photosensitizer. Depending on the kind of the protective film, it may be preferable to incorporate such a photosensitizer and further a photosensitizer.

The photosensitizer is preferably a compound exhibiting maximum absorption in light having a wavelength longer than 380 nm. The photocationic polymerization initiator (B) exhibits maximum absorption at a wavelength of about 300 nm or shorter and generates cationic species or Lewis acid in response to light having a wavelength near that wavelength, thereby initiating cationic polymerization of the polymerizable compound However, when such a photosensitizer is blended, it is also sensitive to light having a wavelength longer than 380 nm, particularly longer than that. As such a photosensitizer, an anthracene-based compound is 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-dipentyloxy Bis (2-methoxyethoxy) anthracene, 9,10-bis (2-ethoxyethoxy) anthracene, 9,10- Methyl- or 2-ethyl-9,10-dimethoxyanthracene, 2-methyl- or 2-ethyl-9,10 Diethoxy anthracene, 2-methyl- or 2-ethyl-9,10-dipropoxyanthracene, 2-methyl- or 2-ethyl-9,10- -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 layer may be formed by, for example, polymerizing the polymerizable compounds (A1) to (A2) and the photocationic polymerization initiator (B) (A3) to (A5) and additives are applied on a polarizing film, or when the first transparent protective film is used, the first transparent protective film is applied, and ultraviolet rays , An electron beam or the like, and curing the coated curable composition. When a layer made of the curable composition is irradiated with an active energy ray, cationic species or Lewis acid is generated from the photocationic polymerization initiator. By the cationic species or Lewis acid, the polymerization of the polymerizable compound proceeds even after irradiation of the active energy ray, whereby the curable composition is cured to form a cured layer.

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

The polarizing plate of the present invention includes the first cured layer composed of the cured product of the curable composition between the polarizing film and the adhesive layer or between the polarizing film and the transparent protective film, The migration of the ionic compound to the polarizing film can be suppressed. Particularly, in the high-temperature and high-humidity environment, the movement of the ionic compound is accelerated by the intrusion of moisture from the outside. In the polarizing plate of the present invention, this can be effectively suppressed. Therefore, the polarizing plate of the present invention can maintain the optical performance.

The first cured layer also serves as an adhesive layer for bonding 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 any particular limitation. For example, a pressure-sensitive adhesive having a base polymer such as acrylic, rubber, urethane, silicone or polyvinyl ether can be used. Further, an energy radiation curable pressure sensitive adhesive, a thermosetting pressure sensitive adhesive, or the like may be used. Among these, a pressure-sensitive adhesive made of an acrylic resin having excellent transparency, adhesive strength, reworkability, weather resistance, heat resistance and the like as a base polymer is suitable.

In the present invention, when the pressure-sensitive adhesive layer comprises an acrylic resin, the acrylic resin is not particularly limited and conventionally known ones can be used. From the viewpoints of adhesiveness and reworkability, It is preferable that the acrylic resin (P) contains the following acrylic resin (P).

The acrylic resin (P) is obtained by the following reaction 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.]

(Hereinafter sometimes referred to as " polar functional group-containing monomer ") having a structural unit derived from a (meth) acrylic acid alkyl ester (P1) represented by the general formula Is an acrylic resin containing structural units.

Here, in the present specification, (meth) acrylic acid means that acrylic acid or methacrylic acid may be used, and the term "(meth)" when referring to (meth) acrylate is also intended.

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

Specific examples of the (meth) acrylic acid alkyl ester (P1) represented by the formula (b) in which R ₂ is an unsubstituted alkyl group include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, Linear alkyl acrylate esters such as lauryl; Branched acrylic acid alkyl esters such as isobutyl acrylate, 2-ethylhexyl acrylate and isooctyl acrylate; Linear methyl methacrylate alkyl esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, n-octyl methacrylate and lauryl methacrylate; Branched alkyl methacrylate such as isobutyl methacrylate, 2-ethylhexyl methacrylate and dioctyl methacrylate, and the like. Of 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 the monomers constituting the acrylic resin (P).

Specific examples of 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 include 2-methoxyethyl acrylate, ethoxymethyl acrylate, methacryl 2-methoxyethyl methacrylate, ethoxymethyl methacrylate, and the like.

These alkyl (meth) acrylate (P1) may be used alone or in combination of two or more different species.

In the polar functional group-containing monomer (P2), the polar functional group may be a free carboxyl group, a hydroxyl group, an amino group, a heterocyclic group including an epoxy ring, and the like. The polar functional group-containing monomer is preferably a (meth) acrylic acid-based compound having a polar functional group. Examples thereof include unsaturated monomers having a free carboxyl group such as acrylic acid, methacrylic acid and? -Carboxyethyl acrylate; (Meth) acrylate such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2- or 3-chloro-2-hydroxypropyl (meth) acrylate and diethylene glycol mono An unsaturated monomer having; (Meth) acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, acrylonitrile, methacrylonitrile, ) Unsaturated monomers having a heterocyclic group such as acrylate, glycidyl (meth) acrylate and 2,5-dihydrofuran; And unsaturated monomers having an amino group different from heterocyclic rings such as N, N-dimethylaminoethyl (meth) acrylate and the like. The polar functional group is preferably a free carboxyl group, a hydroxyl group, an amino group or an epoxy group. These polar functional group-containing monomers may be used alone or in combination of two or more.

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). It is also effective to use, in addition to the unsaturated monomer having a hydroxyl group, an unsaturated monomer having another polar functional group, for example, an unsaturated monomer having a free carboxyl group.

In the acrylic resin (P), the structural unit derived from the (meth) acrylic acid alkyl ester (P1) represented by the formula (b) is preferably 80 to 96 mass% based on the total amount of all the monomers constituting the acrylic resin (P) %, More preferably not less than 82 mass%, further preferably not more than 94 mass%. The structural unit derived from the polar functional group-containing monomer (P2) is preferably 0.1 to 5% by mass, more preferably 0.5% by mass or more, based on the total amount of all the monomers constituting the acrylic resin (P) And preferably 3 mass% or less.

In the polarizing plate of the present invention, the acrylic resin (P) capable of constituting the pressure-sensitive adhesive layer may be a monomer different from the alkyl (meth) acrylate (P1) and the polar functional group-containing monomer (P2) Or may contain a derived structural unit. Examples thereof include a structural unit derived from an unsaturated monomer (P3) having one olefinic double bond and at least one aromatic ring in the molecule (hereinafter sometimes referred to as an " aromatic ring-containing monomer "), (Meth) acrylate ester, a structural unit derived from a styrene monomer, a structural unit derived from a vinyl monomer, a structural unit derived from a monomer having a plurality of (meth) acryloyl groups in the molecule, etc. .

The unsaturated monomer (aromatic ring-containing monomer) (P3) having one olefinic double bond and at least one aromatic ring in the molecule preferably has a (meth) acryloyl group as a group containing an olefinic double bond. Examples thereof include benzyl (meth) acrylate and neopentyl glycol benzoate (meth) acrylate. Among them, the following formula (c):

[Wherein R ₃ represents a hydrogen atom or a methyl group, n represents an integer of 1 to 8, and R ₄ represents a hydrogen atom, an alkyl group, an aralkyl group or an aryl group]

(Meth) acrylic compound represented by the following formula (1).

In the formula (c) representing an aromatic ring-containing (meth) acrylic compound, when R ₄ is an alkyl group, the number of carbon atoms thereof may be from 1 to 9, and when it is an aralkyl group, the number of carbon atoms thereof is from 7 to 11, , The number of carbon atoms thereof may be 6 to 10. Examples of the alkyl group having 1 to 9 carbon atoms include methyl, butyl, nonyl and the like, aralkyl groups having 7 to 11 carbon atoms such as benzyl, phenethyl and naphthylmethyl and aryl groups having 6 to 10 carbon atoms such as phenyl, Naphthyl, and the like.

Specific examples of the aromatic ring-containing (meth) acrylic compound of the formula (c) include (meth) acrylate of 2-phenoxyethyl (meth) acrylate, 2- (2-phenoxyethoxy) ethyl ) Acrylate, and 2- (o-phenylphenoxy) ethyl (meth) acrylate. These aromatic ring-containing monomers may be used alone or in combination of two or more. Among these compounds, preferred are 2-phenoxyethyl (meth) acrylate [a compound wherein R ₄ = H and n = 1 in the formula (c)], 2- (o-phenylphenoxy) ethyl in (c), R ₄ = phenyl in the o-, n = 1] the compounds of the, or (meth) acrylate, 2 (2-phenoxy-ethoxy) ethyl [the formula (c), R ₄ = H, n = 2] is suitable as one of the aromatic ring-containing monomers (P3) constituting the acrylic resin (P).

The alicyclic structure is a cycloparaffin structure having a carbon number of usually 5 or more, preferably 5 to 7. Specific examples of the acrylic acid ester having an alicyclic structure include isobornyl acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, cyclododecyl acrylate, methylcyclohexyl acrylate, trimethylcyclohexyl acrylate, tert-butylcyclohexyl acrylate, Cyclohexyl acrylate, and cyclohexylphenyl acrylate. Specific examples of the methacrylic acid ester having an alicyclic structure include methacrylic acid, isobornyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, methacrylic acid cyclododecane Methylcyclohexyl methacrylate, trimethylcyclohexyl methacrylate, tert-butylcyclohexyl methacrylate, cyclohexylphenyl methacrylate, and the like.

Specific examples of the styrene-based monomer include, in addition to styrene, alkylstyrenes such as methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene and octylstyrene; Halogenated styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene and iodostyrene; Further, nitrostyrene, acetylstyrene, methoxystyrene, divinylbenzene and the like can be mentioned.

Specific examples of the vinyl monomer include fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate and vinyl laurate; Vinyl halides such as vinyl chloride and vinyl bromide; 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; Further, acrylonitrile, methacrylonitrile and the like can be mentioned.

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, (Meth) acrylate, diethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate and tripropylene glycol di A monomer having an acryloyl group; And monomers having three (meth) acryloyl groups in the molecule such as trimethylolpropane tri (meth) acrylate.

Monomers other than the (meth) acrylic acid alkyl ester (P1) and the polar functional group-containing monomer (P2) represented by the formula (b) may be used singly or in combination of two or more. When included in the pressure-sensitive adhesive, the structural units derived from monomers other than the (meth) acrylic acid alkyl ester (P1) and the polar functional group-containing monomer (P2) in the acrylic resin (P) , Usually 0 to 20 parts by mass, and preferably 0 to 10 parts by mass.

The resin component constituting the pressure-sensitive adhesive composition preferably contains two or more kinds of acrylic resins including structural units derived from the (meth) acrylic acid alkyl ester (P1) and the polar functional group-containing monomer (P2) represented by the formula (b) It may be good. The acrylic resin (P) may also be prepared by mixing an acrylic resin having a structural unit derived from (meth) acrylic acid alkyl ester of formula (b) and an acrylic resin not containing a polar functional group .

The acrylic resin (P) containing the structural unit derived from the (meth) acrylic acid alkyl ester (P1) and the polar functional group-containing monomer (P2) represented by the formula (b) 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 a (meth) acrylic acid alkyl ester (P1) and a polar functional group-containing monomer (P2) represented by the formula (b), is a copolymer of a standard polystyrene It is preferable that the weight average molecular weight Mw is in the range of 1 million 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, the possibility of peeling or peeling between the liquid crystal cell and the adhesive layer tends to be lowered, . Further, even if the size of the polarizing plate bonded to the pressure-sensitive adhesive layer is changed, the pressure-sensitive adhesive layer is liable to follow and fluctuate in accordance with the change of the size thereof. Thus, there is no difference between the brightness of the periphery of the liquid crystal cell and the brightness of the center, Tends to be suppressed.

The molecular weight distribution represented by the ratio (Mw / Mn) of the weight average molecular weight Mw to 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 problems such as white spots can be suppressed even when the liquid crystal display panel or the liquid crystal display device is exposed to high temperatures.

It is preferable that the acrylic resin (P) has a glass transition temperature in the range of -10 to -60 占 폚 from the viewpoint of adhesiveness. The glass transition temperature of the resin can be generally 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 the acrylic resin, a polymerization initiator is usually used. The content of the polymerization initiator is preferably 0.001 to 5 parts by mass based on 100 parts by mass of the total amount of all the monomers used for producing the acrylic resin.

As the polymerization initiator, a thermal polymerization initiator, a photopolymerization initiator, and the like are used. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone and the like. 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-methoxy valeronitrile) Azo compounds such as bis (2-methylpropionate) and 2,2'-azobis (2-hydroxymethylpropionitrile); Butyl peroxide, lauryl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, tert-butyl peroxybenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, dipropyl peroxydicarbonate, Organic peroxides such as neodecanoate, tert-butyl peroxypivalate and (3,5,5-trimethylhexanoyl) peroxide; And inorganic peroxides such as potassium persulfate, ammonium persulfate and hydrogen peroxide. A redox-type initiator using a peroxide and a reducing agent in combination may also be used as a polymerization initiator.

As a method of producing the acrylic resin (P), a solution polymerization method is particularly preferable. A specific example of the solution polymerization method is a method of mixing a desired monomer and an organic solvent, adding a thermal polymerization initiator under a nitrogen atmosphere, and stirring at 40 to 90 ° C, preferably 50 to 80 ° C for 3 to 10 hours . 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 dissolved in an organic solvent. 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; Ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and the like.

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

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, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, and the like. Further, an adduct obtained by reacting these isocyanate compounds with a polyol such as glycerol or trimethylolpropane, or an isocyanate compound with a dimer, trimer or the like can also be used as a crosslinking agent for a pressure-sensitive adhesive. It is also possible to use two or more isocyanate compounds in combination.

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, glycerin triglycidyl N, N, N ', N'-tetraglycidyl-m-hexyldiol diglycidyl ether, trimethylolpropane triglycidyl ether, N, N-diglycidyl aniline, Xylylenediamine, and 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane. Two or more kinds of epoxy compounds may be mixed and used.

The aziridine compound is a compound having at least two skeletons of a three-membered ring composed of one nitrogen atom and two carbon atoms, which is also called ethyleneimine, in the molecule, and examples thereof include diphenylmethane-4,4'-bis (1-aziridine Carboxamide), toluene-2,4-bis (1-aziridine carboxamide), triethylene melamine, isophthaloyl bis-1- (2-methyl aziridine), tris- (1-aziridine carboxamide), trimethylolpropane tris- [beta] -aziridinyl propionate, tetramethylolmethane tris- [beta] -aziridinyl propionate, and the like, .

Examples of the metal chelate compound include compounds in which 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 .

Among these crosslinking agents, an isocyanate compound, particularly xylylene diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, or an isocyanate compound is reacted with a polyol such as glycerol or trimethylolpropane, or an isocyanate compound Dimer, trimer or the like, a mixture of these isocyanate compounds, and the like are preferably used. 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 particularly preferable to use at least one isocyanate compound as a crosslinking agent. Among them, preferred isocyanate compounds include tolylene diisocyanate, an adduct obtained by reacting tolylene diisocyanate with a polyol, a trimer of tolylene diisocyanate and a trimer of tolylene diisocyanate, hexamethylene diisocyanate, and hexamethylene diisocyanate as polyol A dimer of hexamethylene diisocyanate, and a trimer of hexamethylene diisocyanate.

In the adhesive layer constituting the polarizing plate of the present invention, the crosslinking agent is preferably 0.01 to 5 parts by mass based on 100 parts by mass of the acrylic resin (P). The content of the crosslinking agent is more preferably 0.1 to 5 parts by mass, and more preferably 0.2 to 3 parts by mass based on 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 spot of the liquid crystal display panel tends to become inconspicuous.

In the present invention, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer preferably contains a silane-based compound, and in particular, it is preferable to contain a silane-based compound in the acrylic resin before the crosslinking agent is blended. The silane-based compound contains a silane-based compound in order to improve the adhesion to glass, so that the adhesion between the liquid-crystal cell sandwiched by the glass substrate and the adhesive layer is improved, and a high adhesion to the display panel can be ensured.

Examples of the silane compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (2-aminoethyl) (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercapto 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropylethoxydimethylsilane and the like . These silane-based compounds may be used alone or in combination of two or more.

The silane-based compound may be a silicone oligomer type. Examples of the silicone oligomer in the form of a (monomer) - (monomer) copolymer include the following.

3-mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-mercaptopropyltriethoxysilane-tetramethoxysilane copolymer And a mercaptopropyl group-containing copolymer such as 3-mercaptopropyltriethoxysilane-tetraethoxysilane copolymer;

Mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer, mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer, mercaptomethyltriethoxysilane-tetramethoxysilane copolymer, and mercaptomethyltri A mercapto methyl group-containing copolymer such as a methoxy silane-tetraethoxy silane copolymer;

3-methacryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane copolymer Tetramethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane- 3-methacryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer and 3-methacryloyloxypropylmethyldione A methacryloyloxypropyl group-containing copolymer such as a methoxy silane-tetraethoxy silane copolymer;

3-acryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropyltriethoxysilane- 3-acryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltrimethoxysilane copolymer, 3-acryloyloxypropyltrimethoxysilane copolymer, 3-acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, and 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymer An acryloyloxypropyl group-containing copolymer such as a polymer;

Vinyltrimethoxysilane-tetramethoxysilane copolymer, vinyltrimethoxysilane-tetraethoxysilane copolymer, vinyltriethoxysilane-tetramethoxysilane copolymer, vinyltriethoxysilane-tetraethoxysilane copolymer Polymer, vinyl methyl dimethoxy silane-tetramethoxy silane copolymer, vinyl methyl dimethoxy silane-tetraethoxy silane copolymer, vinyl methyl diethoxy silane-tetramethoxy silane copolymer and vinyl methyl diethoxy silane-tetraethoxy Vinyl group-containing copolymers such as silane 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-aminopropyltrimethoxysilane- Amino group-containing copolymers such as methyldiethoxysilane-tetramethoxysilane copolymer and 3-aminopropylmethyldiethoxysilane-tetraethoxysilane copolymer.

These silane-based compounds are often liquid. The blending amount of the silane compound in the pressure-sensitive adhesive is usually 0.01 to 10 parts by mass, preferably 0.03 to 1 part by mass, relative to 100 parts by mass (when the two or more kinds are used, the total amount) of the nonvolatile component of the acrylic resin (P) Ratio. When the amount of the silane-based compound relative to 100 parts by mass of the nonvolatile matter of the acrylic resin (P) is within the above range, the adhesion between the pressure-sensitive adhesive layer and the liquid crystal cell is improved, and the bleed- It is preferable because it tends to be suppressed.

In the present invention, the adhesive layer contains an ionic compound. The ionic compound may function as an antistatic agent. Particularly, when the acrylic resin (P) contains an aromatic ring-containing (meth) acrylic compound represented by the above formula (c) and n is 2 or more in the formula (c) By adding an ionic compound to a pressure-sensitive adhesive containing a copolymerized acrylic resin, good antistatic properties can be imparted while giving a white spot suppression effect. The ionic compound used herein is a compound that exists in combination of a cation and an anion. The cation and the anion may be inorganic or organic, respectively. From the viewpoint of compatibility with the acrylic resin (P), at least And one is an ionic compound containing an organic group.

Examples of the inorganic cations constituting the ionic compound include alkali metal ions such as lithium cations [Li ⁺ ], sodium cations [Na ⁺ ], potassium cations [K ⁺ ] and cesium cations [Cs ⁺ ]; Alkaline earth metal ions such as beryllium cation [Be ^{2 +} ], magnesium cation [Mg ^{2 +} ] and calcium cation [Ca ^{2 +} ]. Among them, it is preferable to use a lithium cation [Li ⁺ ], a potassium cation [K ⁺ ] or a sodium cation [Na ⁺ ] from the viewpoint of metal corrosion resistance, and from the viewpoint of durability, a potassium cation [K ⁺ More preferable.

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

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

Specific examples of the pyridinium cations represented by the formula (d) include the following.

Butyl-4-methylpyridinium cation, N-butyl-2,4-diethylpyridinium cation, N-butyl-2-hexylpyridinium cation, N Butylpyridinium cation, an N-hexyl-4-methylpyridinium cation, an N-hexyl-4-ethylpyridinium cation, an N-hexyl- Pyridinium cation, N-octyl-4-ethylpyridinium cation, N-octylpyridinium cation and the like.

The ammonium cation represented by the formula (e) is a tetraalkylammonium cation, and the tetraalkylammonium cation is preferably 20 or more, and more preferably 22 or more, from the viewpoint of compatibility with the acrylic resin (P) . The total carbon number is preferably 36 or less, and more preferably 30 or less.

Specific examples of the tetraalkylammonium cations represented by the formula (e) include the following.

Tetrahexylammonium cation, tetraoctylammonium cation, tributylmethylammonium cation, trihexylmethylammonium cation, trioctylmethylammonium cation, tridecylmethylammonium cation, trihexylethylammonium cation, trioctylethylammonium cation, and the like.

On the other hand, examples of the anions constituting the ionic compound include the following.

A chlorinated anion [Cl ^- ], a bromide anion [Br ^- ], an iodide anion [I ^- ], a tetrachloroaluminate anion [AlCl ^{4 -} ], a heptachlorodialuminate anion [Al ₂ Cl ₇ ^- ], a tetrafluoro Robo anion [BF ₄ ^-], phosphate anion hexafluorophosphate [PF ₆ ^-], perchlorate anion [ClO ₄ ^-], nitrate anions [NO ₃ ^-], acetate anion [CH ₃ COO ^-], trifluoroacetate anion [CF ₃ COO ^-], methane sulfonate anion [CH ₃ SO ₃ ^-], trifluoromethanesulfonate anion [CF ₃ SO ₃ ^-], (methanesulfonyl-trifluoromethyl) bis imide anion [(CF ₃ SO _{2) 2} N ^-], tris (trifluoromethane sulfonyl) meth arsenide anion _{[(CF 3 SO 2) 3 C} - ], hexafluoro-acetoxy anion [AsF ₆ ^-], antimonate hexafluoro anion [SbF ₆ ^-], hexafluoro-NO Sites anion [NbF ₆ ^-], tantalum anion [TaF ₆ ^-] hexafluoropropane, (poly) fluoride anion [F (HF) _n ^-] as hydro-fluoro (n is 1-3 or so), thiocyanate anion [ SCN ^-], DC hold imide anion [(CN) ₂ N ^-], butane sulfonate anion perfluoro [C ₄ F ₉ SO ₃ ^-], bis (ethanesulfonyl pentafluorophenyl) imide anion [(C ₂ F ₅ SO _{2) 2} N ^-], butanoate anionic perfluoro [C ₃ F ₇ COO ^-], (methanesulfonyl) trifluoroacetate (methane-carbonyl) imide anion trifluoroacetate [(CF ₃ SO ₂ ) (CF ₃ CO) N ^- ] and the like.

Concrete examples of the ionic compound may be appropriately selected from combinations of the above-mentioned cations and anions. Specific examples of the ionic compound which is a combination of a cation and an anion include the following.

Lithium bis (trifluoromethanesulfonyl) imide, lithium hexafluorophosphate, lithium iodide (lithium iodide), lithium bis (pentafluoroethanesulfonyl) imide, lithium tris (trifluoromethanesulfonyl) Sodium bis (trifluoromethanesulfonyl) imide, sodium bis (pentafluoroethanesulfonyl) imide, sodium tris (trifluoromethanesulfonyl) methanide, potassium bis (trifluoromethane sulfonyl) imide, (Pentafluoroethanesulfonyl) imide, potassium tris (trifluoromethanesulfonyl) methanide, N-methyl-4-hexylpyridinium bis (trifluoromethanesulfonyl) imide (Trifluoromethanesulfonyl) imide, N-butyl-2-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-hexyl- 4-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-methyl-4-hexyl Methylpyridinium 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- (Trifluoromethanesulfonyl) imide, trioctylmethylammonium bis (trifluoromethanesulfonyl) imide, trihexylmethylammonium bis (trifluoromethanesulfonyl) imide, trioctylmethylammonium bis Methanesulfonyl) imide, tetrahexylammonium hexafluorophosphate, tributylmethylammonium hexafluorophosphate, trihexylmethylammonium hexafluorophosphate, trioctylmethylammonium hexafluorophosphate Agent, tetrahexylammonium perchlorate, tributyl methyl ammonium perchlorate, tri-methyl-hexyl ammonium perchlorate, trioctyl methyl ammonium perchlorate and the like.

These ionic compounds may be used either individually or in combination of two or more. The content of the ionic compound is usually 0.5 to 8 parts by mass, preferably 0.8 to 4 parts by mass based on 100 parts by mass of the acrylic resin (P).

In the present invention, the adhesive layer may further contain a crosslinking catalyst, a weathering stabilizer, a tackifier, a plasticizer, a softener, a dye, a pigment, an inorganic filler, a resin other than an acrylic resin, and the like.

It is also useful to form a harder adhesive layer by blending an ultraviolet curable compound such as a polyfunctional acrylate and a photoinitiator in an adhesive and irradiating ultraviolet rays after curing the adhesive layer. This implements the second crosslinking structure in the pressure-sensitive adhesive to improve durability such as heat resistance. When a crosslinking catalyst is used together with a crosslinking agent in a pressure-sensitive adhesive, it is possible to prepare the pressure-sensitive adhesive layer with aging for a short period of time. In the polarizing plate comprising the obtained pressure-sensitive adhesive, peeling or peeling may occur between the polarizing plate and the pressure- It is possible to suppress occurrence of foaming in the case of the above-mentioned method, and the reheat property 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 And the like. When an amine compound is added to the pressure-sensitive adhesive as a crosslinking catalyst, an isocyanate compound is suitable as the crosslinking agent.

It is also possible to add a fine particle to obtain an adhesive layer showing light scattering properties. An antioxidant, an ultraviolet absorber, or the like may be blended in the adhesive layer. Examples of the ultraviolet absorber include a salicylate ester compound, a benzophenone compound, a benzotriazole compound, a cyanoacrylate compound, and a nickel complex salt compound.

The pressure-sensitive adhesive layer can be formed, for example, by applying a pressure-sensitive adhesive as described above to an organic solvent solution, coating the pressure-sensitive adhesive layer on a film or layer (for example, polarizing film or the like) to be laminated by a die coater or a gravure coater, have. It is also possible to form a sheet-type pressure-sensitive adhesive on a release-treated plastic film (called a separate film) by transferring the pressure-sensitive adhesive onto a film or layer to be laminated. The thickness of the adhesive layer is not particularly limited, but is preferably in the range of 2 to 40 占 퐉, more preferably in the range of 5 to 35 占 퐉, and further preferably in the range of 10 to 30 占 퐉.

The pressure-sensitive adhesive layer preferably has a storage elastic modulus at a temperature of 23 to 80 캜 of 0.10 to 5.0 MPa, more preferably 0.15 to 1.0 MPa. When the storage elastic modulus at 23 to 80 캜 is 0.10 MPa or more, white spots due to the shrinkage of the polarizing plate when the liquid crystal display panel in a state in which the polarizing plate is bonded to the liquid crystal cell are exposed to high temperatures and the like can be suppressed.

If it is 5 MPa or less, the durability is less likely to deteriorate due to the deterioration of the adhesive strength, which is preferable. Here, "storage elastic modulus at 0.1 to 5.0 MPa at 23 to 80 ° C" means that the storage elastic modulus takes a value within the above range at any temperature within this range. Since the storage elastic modulus usually decreases with temperature rise, if the storage elastic moduli at 23 deg. C and 80 deg. C fall within the above range, the adhesive layer shows the storage elastic modulus within the above range at the temperature within this range . 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, a silane-based compound as a copolymer of butyl acrylate, methyl acrylate, 2-hydroxyethyl acrylate, 2-phenoxyethyl acrylate and acrylic acid, Compounds, and antistatic components.

[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. In the present invention, the polarizing film is a film in which a dichroic dye is contained in a polyvinyl alcohol- . As the polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based resin film, a saponified polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as copolymers of vinyl acetate and other monomers copolymerizable therewith (for example, ethylene-vinyl acetate copolymer). 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 resin may be modified, and examples thereof include polyvinyl formal modified with aldehydes, polyvinyl acetal, and polyvinyl butyral. The degree of polymerization of the polyvinyl alcohol-based resin is usually 1000 to 10000, preferably 1500 to 5000.

A film obtained by forming such a polyvinyl alcohol-based resin can be used as the original film of the polarizing film. The method for forming the polyvinyl alcohol-based resin is not particularly limited, and a film can be formed by a conventionally known method. The thickness of the original film made of the polyvinyl alcohol-based resin is not particularly limited, but is 10 to 150 占 퐉, preferably 15 to 100 占 퐉, more preferably 20 to 80 占 퐉 in consideration of easiness of stretching.

The polarizing film usually has a step of uniaxially stretching the polyvinyl alcohol based resin film, a step of adsorbing the dichroic dye by staining the polyvinyl alcohol based resin film with a dichroic dye, a step of adsorbing the dichroic dye to the polyvinyl alcohol- A step of treating the resin film with an aqueous solution of boric acid and a step of washing with water after treatment with an aqueous solution of boric acid.

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 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 perform uniaxial stretching in a plurality of these steps.

In uniaxial stretching, the film may be uniaxially stretched between rolls having different circumferential velocities, or may be uniaxially stretched using a heat roll. The uniaxial stretching may be dry stretching in which drawing is performed in the atmosphere, or wet stretching in which a polyvinyl alcohol based resin film is stretched by using a solvent. The stretching magnification is preferably 8 times or less, more preferably 7.5 times or less, and still more preferably 7 times or less from the viewpoint of suppressing deformation of the polarizing film.

Further, the stretching magnification is preferably 4.5 times or more from the viewpoint of developing the function as a polarizing film.

As a method for dyeing a polyvinyl alcohol-based resin film with a dichroic dye, for example, there is a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye. As the dichroic dye, for example, iodine or a dichroic dye is used. The dichroic dye includes, for example, C.I. DIRECT RED 39 and the like, dichromatic direct dyes consisting of trisazo, tetrakisazo compounds and the like. It is preferable that the polyvinyl alcohol-based resin film is subjected to immersion treatment with water before the dyeing treatment.

When iodine is used as the dichroic dye, a method in which a polyvinyl alcohol resin film is dipped in an aqueous solution containing iodine and potassium iodide is generally 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 dichroism dye, the temperature of the aqueous solution used for dyeing is usually 20 to 40 占 폚, 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 dying and dyeing the polyvinyl alcohol resin film into an aqueous solution containing a water-soluble dichroic dye is generally employed. The content of the dichroic dye in the aqueous solution is usually 1 × 10 ^-4 to 10 parts by mass, preferably 1 × 10 ^-3 to 1 part by mass, and particularly preferably 1 × 10 ^-3 To 1 x 10 < ^-2 > parts by mass. The 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 dye aqueous solution used for dyeing usually has a temperature of 20 to 80 DEG C, and the dipping time (dyeing time) in the aqueous solution is usually 10 to 1,800 seconds.

The boric acid treatment after dyeing with the dichroic dye can be carried out by immersing the dyed polyvinyl alcohol resin film in an aqueous solution containing boric acid. The amount of boric acid in the aqueous solution containing boric acid 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, it is preferable that the aqueous solution containing boric acid contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is usually 0.1 to 15 parts by mass, and 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 占 폚 or higher, preferably 50 to 85 占 폚, and more preferably 60 to 80 占 폚.

The polyvinyl alcohol resin film after boric acid treatment is usually subjected to water washing treatment. The water washing treatment can be carried out, for example, by immersing the boric acid-treated polyvinyl alcohol resin film in water. The temperature of the water in the water washing treatment is usually 5 to 40 캜, and the immersing time is usually 1 to 120 seconds. After washing with water, drying treatment is carried out 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 占 폚, preferably 40 to 95 占 폚, and more preferably 50 to 90 占 폚. The drying treatment time is usually 60 to 600 seconds, preferably 120 to 600 seconds.

Thus, the polyvinyl alcohol-based resin film is subjected to uniaxial stretching, dyeing with a dichroic dye, and boric acid treatment to obtain a polarizing film. The thickness of the polarizing film may be, for example, 5 to 40 탆.

[Second hardened layer]

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

In one embodiment of the present invention, the second cured layer also functions as an adhesive for bonding a polarizing film and a transparent protective film (5 in Figs. 1 and 2) stacked on the opposite side of the liquid crystal cell Therefore, when the curable composition of the second cured layer is different from the curable composition of the first cured layer, the curable composition of the second cured layer may be a photo-curable adhesive well known in the art. Examples of the photo-curable adhesive include a mixture of a photo-curable epoxy resin and a photo cationic polymerization initiator, and a photo-curable acrylic resin and a photo radical polymerization initiator. The curable composition forming the cured product constituting the second cured layer is appropriately selected according to the adhesiveness with the polarizing film or the second transparent protective film, and is suitably selected, for example, from the photocurable component described in the pamphlet of International Publication No. 2014/129368 And a photocurable adhesive containing a photocationic polymerization initiator can be used.

In the present invention, the second cured layer can be formed by applying a curable composition (photo-curable adhesive) to a surface of the polarizing plate opposite to the surface on which the first cured layer is laminated by a known method. For example, a casting method, a Meyer 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 flexible method is a method of spreading a film as an object to be coated while moving the film in a substantially vertical direction, a substantially horizontal direction, or an oblique direction between them while flowing an adhesive on the surface. After the curable composition is applied, the polarizing film and the transparent protective film bonded to the polarizing film are superimposed, and the film is sandwiched by a nip roll or the like. The bonding of the film using the nip roll can be carried out by, for example, applying the curable composition, then pressing it with a roll or the like and spreading it evenly, spreading the curable composition through a roll between the rolls, Can be adopted. In this case, the material of the roll used may be metal or rubber. Further, in the case where the film is spread between a plurality of rolls to spread out, the plurality of rolls may be made of the same material or different materials.

When a photo-curable adhesive is used, the photo-curable adhesive is cured by irradiating an active energy ray. The light source of the active energy ray is not particularly limited, but an active energy ray having a light emission distribution with a wavelength of 400 nm or less is preferable. Specifically, low energy mercury lamps, medium pressure mercury lamps, high pressure mercury lamps, ultra high pressure mercury lamps, Mercury lamp, metal halide lamp and the like are preferable.

The light irradiation intensity to the photo-curing adhesive is appropriately determined according to the composition of the photo-curable 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 6000 mW / Preferably 10 to 1000 mW / cm2, and more preferably 20 to 500 mW / cm2. When the irradiation intensity is within the above range, the reaction time can be secured, and the yellowing of the epoxy resin and the deterioration of the polarizing film due to heat radiated from the light source and heat generation at the time of curing of the photo-curable adhesive can be suppressed. The light irradiation time to the photo-curing adhesive is appropriately selected according to the photo-curable adhesive to be cured and is not particularly limited, but the integrated light quantity represented by the product of the irradiation intensity and the irradiation time is preferably 10 to 10,000 mJ / M2, more preferably 50 to 1000 mJ / m2, and further preferably 80 to 500 mJ / m2. When the total amount of light to the photo-curing adhesive is within the above range, a sufficient amount of active species derived from the polymerization initiator can be generated sufficiently to allow the curing reaction to proceed more surely, and the irradiation time does not become too long, .

When the photo-curable adhesive is cured by irradiation of an active energy ray, various functions of the polarizing plate, such as polarizing degree, transmittance and hue of the polarizing film, transparency of the transparent protective film and various films constituting the optical layer, It is preferable to perform the curing under a condition that the temperature is not lowered. The thickness of the second cured layer is not particularly limited, but is usually 0.1 to 10 탆.

[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 through a first cured 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 through a second cured layer . From the viewpoint of contributing to prevention of shrinkage and expansion of the polarizing film, deterioration of the polarizing film due to temperature, humidity, ultraviolet rays, etc., in one embodiment, the polarizing plate of the present invention has a transparent protective film.

On the other hand, in one embodiment, in view of thinning of the polarizing plate, the polarizing plate of the present invention does not include the first transparent protective film.

The material for forming the transparent protective film is preferably excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like. For example, there may be mentioned polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulosic polymers such as diacetylcellulose and triacetylcellulose, acrylic polymers such as polymethylmethacrylate, polystyrene and acrylonitrile-styrene copolymer (AS Resin), and polycarbonate-based polymers. Further, it is also possible to use a polyolefin-based polymer such as polyethylene, polypropylene, a cyclo- or norbornene-structure polyolefin, an ethylene-propylene copolymer, an amide polymer such as nylon or aromatic polyamide, Based polymers, polyether ether ketone-based polymers, polyphenylene sulfide-based polymers, vinyl alcohol-based polymers, vinylidene chloride-based polymers, vinyl butyral-based polymers, arylate-based polymers, polyoxymethylene- Epoxy-based polymers, blends of the above-mentioned polymers, and the like are examples of polymers forming transparent protective films. The transparent protective film may be formed as a cured layer of a thermosetting or ultraviolet curable resin such as acrylic, urethane, acrylic urethane, epoxy, or silicone. Among them, those having a hydroxyl group having reactivity with an isocyanate-based crosslinking agent are preferable, and a cellulose-based 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 탆 or less, preferably 1 to 300 탆, more preferably 5 to 200 탆 , More preferably from 10 to 100 탆. The transparent protective film may be composed of a transparent protective film to which an optical compensation function is added.

In the polarizing plate of the present invention, since the first cured layer can effectively suppress the movement of the ionic compound from the adhesive layer to the polarizing film, the selection range concerning the material of the first transparent protective film constituting the polarizing plate is widened . That is, it is not necessary to use a transparent protective film which is difficult to permeate an ionic compound, and it becomes possible to constitute a polarizing plate by using a transparent protective film which is easily permeable to an ionic compound. Accordingly, the production cost can be reduced, and the polarizing plate of the present invention is advantageous from an industrial point of view.

Specifically, it is immersed in an aqueous 50% by mass potassium iodide solution at 23 ° C and 60% RH for 4.5 hours, taken out, rinsed for 15 seconds at 23 ° C in the air, dried in a cow at 23 ° C for 15 hours A transparent protective film having an absorbance with respect to light having a wavelength of 360 nm after treatment is preferably at least 5% higher than the absorbance (initial absorbance) before this treatment can be used as the first transparent protective film. The increase in the absorbance after the treatment with respect to the initial absorbance may be 10% or more and 15% or more from the viewpoint of enlarging the selection range concerning the material of the first transparent protective film. In addition, the increase of the absorbance after the treatment with respect to the initial absorbance is usually 25% or less.

The polarizing plate of the present invention may further laminate an optical layer such as a retardation film, a time compensating film and a luminance improving film as necessary. In the polarizing plate of the present invention, the optical layer can be formed using materials well known in the art.

The polarizing plate of the present invention can be produced by a known method. For example, a layer of a second curable composition is formed by applying a curable composition to a transparent protective film, and a polarizing film is bonded to the layer of the second curable composition to form a laminate. In the case of a polarizing plate not including the first transparent protective film, the first curable composition layer is formed by applying the curable composition on the release film, and the polarizing film side of the laminate is bonded to the coated surface. Subsequently, the second curable composition layer and the first curable composition layer are cured by irradiating active energy rays such as ultraviolet rays and electron beams to form a second cured layer and a first cured layer, and the release film is peeled, 1 adhesive layer may be formed on the curable composition layer. On the other hand, in the case of a polarizing plate comprising a first transparent protective film, a curable composition is applied on a transparent protective film to form a first cured layer, the polarizing film side of the laminate is bonded to the coated surface, , An active energy ray such as an electron beam may be irradiated to form a first cured layer, and then an 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. The polarizing plate according to the present invention can be suitably used as a polarizing plate for an image display panel because deterioration of optical performance can be suppressed even in use under high temperature and high humidity environment and / or for a long period of time. It is difficult for the image display apparatus having the polarizing plate of the present invention to have problems in image display performance.

[ Example ]

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by these Examples. In the examples and comparative examples, "% " and " part " refer to " mass% " and " part by mass "

1. Laminate  Production of A

The polymerizable compounds (a-1), (a-2), (a-3) and (a-4) described below and the photocationic polymerization initiator (b-1) were mixed to prepare a curable composition a .

(a-1) 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate 25 parts by mass

(a-2) Neopentyldiglycidyl ether 55 parts by mass

(a-3) 15 parts by mass of a polymer (GMA-PMMA (polymethylmethacrylate) copolymer) having a weight average molecular weight of 15000 radically polymerized with a monomer consisting of 25 parts of glycidyl methacrylate and 75 parts of methyl methacrylate

(a-4) 5 parts by mass of hydroxybutyl vinyl ether

(b-1) triarylsulfonium hexafluorophosphate 2.25 parts by mass

A corona discharge treatment was carried out on the surface of an acrylic resin (PMMA) film (trade name: Technoloy S001, manufactured by Sumitomo Chemical Co., Ltd.) (second transparent protective film) having a thickness of 60 占 퐉 including an ultraviolet absorber, The curable composition a was coated on the discharge-treated surface using a bar coater so that the film thickness after curing was about 3 탆 to form a layer of the curable composition a. A polyvinyl alcohol (PVA) -iodine-based polarizing film having a thickness of 25 占 퐉 was bonded to this layer to prepare a laminate. On the polarizing film side of this laminate, an ultraviolet ray was irradiated at a wavelength of 280 nm to 320 nm at an amount of 200 mJ / cm 2 using an ultraviolet irradiator equipped with a belt conveyor (lamp: "D bulb" manufactured by Fusion UV Systems Co., Ltd.) To cure the curable composition a to prepare a laminate A comprising an acrylic resin film (second transparent protective film) / a second cured layer / a polarizing film.

2. Preparation of pressure-sensitive adhesive composition

The acrylic pressure-sensitive adhesive was prepared as follows.

Azobisisobutyronitrile 0.14 as a polymerization initiator was added to 70.4 parts by mass of butyl acrylate, 20.0 parts by mass of methyl acrylate, 0.6 part by mass of acrylic acid, 8.0 parts by mass of 2-phenoxyethyl acrylate and 1.0 part by mass of 2- And polymerization reaction was carried out to prepare an acrylic resin. 0.45 mass% of an isocyanate crosslinking agent (Colonate L: ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75%), manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to 20.0 mass parts of the solid content of the acrylic resin , 0.45 parts by mass of a silane coupling agent (KBM-403: 3-glycidoxypropyltrimethoxysilane (liquid), Shin-Etsu Chemical Co., Ltd.), and 0.45 parts by mass of an antistatic agent (1-hexylpyridinium hexafluoro Phosphate (compound represented by the following formula (f))) was added to prepare an organic solvent solution of an acrylic resin pressure-sensitive adhesive.

[Example 1]

First, each of the polymerizable compounds shown in Table 1 and the cationic polymerization initiator (b-1) were mixed in respective amounts to prepare a curable composition b. Subsequently, one surface of a cellulose-based transparent protective film (ZRE34, manufactured by Fuji Film Co., Ltd.) having a thickness of 34 占 퐉 was subjected to corona discharge treatment to form a curable composition b on the surface thereof, Was about 3 占 퐉. On the coated surface, the laminate A was bonded to the polarizing film side to produce a laminate. On the side of the cellulose-based transparent protective film of this laminate, an integrated amount of light with a wavelength of 280 nm to 320 nm of 200 mJ / cm 2 was irradiated using an ultraviolet irradiator equipped with a belt conveyor (lamp: "D bulb" manufactured by Fusion UV Systems Co., Ltd.) So that the curable composition b was cured. Thus, a laminate B comprising an acrylic resin film (second transparent protective film) / second cured layer / polarizing film / first cured layer / cellulose-based transparent protective film (first transparent protective film) was produced.

The organic solvent solution of the acrylic resin pressure-sensitive adhesive was applied to a releasable polyethylene terephthalate film (trade name: SP-PLR382050, manufactured by Lin Tec Co., Ltd. (hereinafter referred to as "release film")) The coated surface was coated with a die coater so as to have a thickness of 20 탆 after drying, and dried to produce a sheet-type pressure-sensitive adhesive having a release film. Thereafter, on the side of the cellulose-based transparent protective film (first transparent protective film) of the layered product B, the surface (adhesive surface) opposite to the release film side of the sheet-shaped adhesive was laminated by a laminator, And a relative humidity of 65% for 7 days to obtain a polarizing plate (1) having a pressure-sensitive adhesive layer. This polarizing plate has a constitution in which a peeling film is bonded onto an adhesive layer.

Durability evaluation

The obtained polarizing plate 1 was cut to a size of 30 mm x 30 mm, the peeled film was peeled off, and bonded to an alkali-free glass (trade name "EAGLE XG" manufactured by Corning Incorporated) on the adhesive layer side. The durability of the obtained sample was evaluated as follows.

The sample was subjected to an autoclave treatment at a temperature of 50 캜 and a pressure of 5 kg / cm 2 (490.3 kPa) for 1 hour, and then maintained at an ambient temperature of 23 캜 and a relative humidity of 55% for 24 hours. With respect to this sample, an optional accessory "film holder equipped with a polarizing film" was set on a spectrophotometer (UV2450, manufactured by Shimadzu Corporation) at the time of extinction and the transmittance of the polarizer in the wavelength range of 380 to 700 nm The transmission spectrum in the axial direction and the absorption axis direction was measured, and the polarization degree Py (unit:%) was determined based on these measurements. The polarization degree of this state was regarded as the initial polarization degree (Py after the test). Thereafter, the degree of polarization (initial Py) after the test was determined in the same manner as above with respect to the sample after standing for 12 hours under the environment of 85% relative humidity at 85%. The optical performance in the state before standing for 12 hours under the environment of 85 캜 and 85% relative humidity was used as an initial value, and the degree of polarization degree change ΔPy was calculated from the following equation. 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 ", trade name; manufactured by Fuji Film Co., Ltd.) with respect to the light having a wavelength of 360 nm was measured using an ultraviolet spectrophotometer [Shimazu Seisakusho "UV2450" , And the absorbance was taken as the initial absorbance. Subsequently, this film was immersed in an aqueous 50% by mass potassium iodide solution at 23 ° C and 60% RH for 4.5 hours, taken out, washed with water at 23 ° C in the atmosphere, and dried in a cow at 23 ° C for 15 hours Processing. With respect to the film after the treatment, the absorbance with respect to light having a wavelength of 360 nm was measured and found to be increased by 22% with respect to the initial absorbance.

[Examples 2 to 10]

(Second transparent protective film) / second cured layer / second cured film was prepared in the same manner as in Example 1, except that the curable composition prepared by mixing the respective compounds shown in Table 1 for each usage was used instead of the curable composition b. A laminate comprising a polarizing film / first cured layer / cellulose-based transparent protective film (first transparent protective film) was produced.

Subsequently, an adhesive layer was provided in the same manner as in Example 1 to obtain the 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 obtained in the same manner as in Example 1, except that each of the compounds shown in Table 1 was mixed at each use amount to prepare a curable composition d and applied to a cellulose-based transparent protective film. The durability of the polarizing plate 11 was evaluated. The results are shown in Table 1.

[Comparative Examples 2 to 7]

Polarizers (12) to (17) were obtained in the same manner as in Example 1 except that each compound shown in Table 1 was mixed at each use amount to prepare a curable composition e and applied to a cellulose-based transparent protective film . The durability of each of the polarizers 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 (Doagosei 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 compounds (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- ] Ethyl] phenyl] propane (TECHMORE VG3101L, Purintech)

Aromatic epoxy compound (2): Resorcinol diglycidyl ether (EX-201, Nagase Chemtex Co., Ltd.)

Aromatic epoxy compound (3): Bis F type epoxy (jER806, manufactured by Mitsubishi Chemical)

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-hydroxymethyloxetane (OXT101, manufactured by Toagosei Co., Ltd.)

· Gwangyang ion 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 exhibit no significant change in optical performance and exhibit high durability because the polarization degree change? On the other hand, in the polarizing plates (11) to (17) obtained in Comparative Examples 1 to 7, the polarization degree change?

1: polarizing film
2: First cured layer
3: Adhesive layer
4: Second cured layer
5: Second transparent protective film
6: First transparent protective film
10: polarizer
X: liquid crystal cell

Claims (3)

A first cured layer composed of a cured product of a curable composition containing a polymerizable compound and an adhesive layer containing an ionic compound are laminated on one surface of a polarizing film containing a dichroic dye in a polyvinyl alcohol- Wherein the curable composition is a polarizing plate containing, in this order,
(A1) an oxetane compound having at least two oxetanyl groups, and
(A2) an aliphatic epoxy compound having two or more epoxy groups
≪ / RTI >
The curable composition preferably contains, relative to 100 mass% of the total amount of the polymerizable compound,
(A1) of 15 to 70 mass%, and
(A2) 3 to 40 mass%
≪ / RTI >
Wherein the content of the oxetane compound (A3) having one oxetanyl group is 10 mass% or less based on 100 mass% of the total amount of the polymerizable compound. The image display device according to claim 1, further comprising a first transparent protective film between the first cured layer and the adhesive layer, wherein the first transparent protective film is formed of a 50% by mass aqueous solution of potassium iodide in an atmosphere of 23 ° C and 60% RH The absorbance with respect to the light having a wavelength of 360 nm after the treatment of immersing for 4.5 hours, taking out, washing with water at 23 캜 for 15 seconds in air and drying in a dark place at 23 캜 for 15 hours, Polarizer with higher than 5%. The polarizing plate according to claim 1 or 2, further comprising a second transparent protective film on a surface of the polarizing film opposite to the first cured layer side through a second cured layer.

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