KR101686666B1 - Polarizing plate, optical member and liquid crystal display - Google Patents

Abstract

The present invention relates to a polarizing plate having a protective layer on at least one surface of a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol based resin film, wherein the protective layer has a curable property And a surface resistance value of the protective layer is 10 ¹³ ? /? Or less, and an optical member using the polarizing plate and a liquid crystal display device.

A polarizing film, a protective layer, a polarizing plate, an active energy ray curable compound, an antistatic agent, an optical member, a liquid crystal display

Description

TECHNICAL FIELD [0001] The present invention relates to a polarizing plate, an optical member, and a liquid crystal display device using the polarizing plate, the optical member, and the liquid crystal display.

The present invention relates to a polarizing plate having a protective layer having antistatic properties on one side or both sides of a polarizing film on which a dichromatic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film. The present invention also relates to an optical member and a liquid crystal display device using the polarizing plate.

The polarizing plate is useful as an optical component constituting a liquid crystal display device. Conventionally, as a polarizing plate, those having a structure in which a protective layer containing a transparent resin film is laminated on one side or both sides of a polarizing film by using an aqueous adhesive or the like is used. A triacetyl cellulose film (TAC film) is widely used as such a transparent resin film because of its excellent optical transparency and moisture permeability. The polarizing plate is bonded to the liquid crystal cell with a pressure-sensitive adhesive through another optically functional layer as required, and inserted into the liquid crystal display device.

BACKGROUND ART [0002] In recent years, with the development of mobile devices such as notebook type personal computers, cellular phones, car navigation systems, etc. of liquid crystal display devices, a polarizing plate constituting a liquid crystal display device is required to be thin in weight and high in durability (high mechanical strength) have. In a liquid crystal display device for mobile use, it is desired to be usable even under humid heat, and a polarizer used therefor is required to have high humidity and heat resistance. However, when a conventional polarizer is exposed to a high humidity, Or the polarizing film shrinks. Therefore, it is required that the protective layer to be laminated on the polarizing film is made thin and lightweight, and at the same time, it is required to improve the mechanical strength and the ability to suppress the shrinkage of the polarizing film (shrinkage restraining force) by increasing the hardness.

However, in the polarizing plate in which the TAC film is bonded as the protective layer, it is difficult to reduce the thickness of the protective layer to 20 μm or less in terms of handling and durability at the time of work, which limits the reduction in thickness and weight.

As a technique capable of solving the above problem, for example, a technique of forming a transparent thin film layer by coating a resin solution on one side or both sides of a polarizing film made of a hydrophilic polymer is disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2000-199819) . In addition, Patent Document 2 (Japanese Unexamined Patent Application, First Publication No. 2003-185842) discloses an energy ray curable composition containing an energy ray polymerizable compound having a dicyclopentyl residue or a dicyclopentenyl residue, Is disclosed. Patent Document 3 (Japanese Patent Application Laid-Open No. 2004-245924) discloses a polarizing plate having a protective film composed mainly of an epoxy resin on at least one surface of a polarizing film. Patent Document 4 (Japanese Patent Laid-Open Publication No. 2005-92112) discloses that at least one surface of a polarizing film is protected with a cured product of an active energy ray-curable resin composition.

Usually, the polarizing plate has a pressure-sensitive adhesive layer formed on the surface of at least one of the protective films, and the pressure-sensitive adhesive layer is in a state in which the release film is adhered on the pressure-sensitive adhesive layer. When the polarizing plate is bonded to the liquid crystal cell, the release film is peeled from the polarizing plate and bonded to the liquid crystal cell through the exposed pressure-sensitive adhesive layer. When the release film is peeled and bonded to the liquid crystal cell, static electricity is generated, The liquid crystal driver portion of the liquid crystal display device may be destroyed, so development of countermeasures against such a problem is desired.

The polarizing plate with a pressure-sensitive adhesive layer as described above is bonded to a liquid crystal cell on the pressure-sensitive adhesive layer side to form a liquid crystal display. When a polarizing plate with a pressure-sensitive adhesive layer is bonded to a liquid crystal cell, Once the film is peeled off, a new polarizing plate is again bonded again. In such a case, static electricity is generated at the time of peeling of the polarizing plate, and the liquid crystal driver portion of the liquid crystal display device may be destroyed. Therefore, development of countermeasures against such a problem is also desired.

As a technique capable of solving the problem that the polarizing plate is charged, for example, Patent Document 5 (Japanese Patent Application Laid-Open No. 62-6505) discloses a compound having an unsaturated bond polymerizable by radiation, , Zn, Sn, and In, and the like, and a conductive fine particle having an average particle diameter of not more than 0.2 μm is polymerized and cured.

Claims 1 and 2 of Patent Document 6 (Japanese Patent No. 3310706) disclose the use of an antistatic agent, a fluorine-based or silicon-based leveling agent which becomes transparent after curing of a resin in a UV-curable resin, and a transparent resin Is coated on a triacetylcellulose film and the transparent resin is cured by ultraviolet rays to form a cured coating film having antistatic performance. Claim 1 of Japanese Patent Application Laid-Open No. 2005-144849 discloses a transparent conductive film containing conductive fine particles, wherein the transparent conductive film in which the conductive fine particles are localized in the vicinity of one main surface of the film Lt; / RTI >

An object of the present invention is to provide a polarizing plate which is thin and lightweight and hardness of a protective layer is improved while maintaining good adhesion between a polarizing film and a protective layer, and further, is prevented from being charged by static electricity. Another object of the present invention is to provide an optical member and a liquid crystal display device using such a polarizing plate.

The present invention relates to a polarizing plate having a protective layer on at least one surface of a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, wherein the protective layer has a curable property Wherein the protective layer has a surface resistance of 10 ¹³ ? /? Or less.

The curable composition preferably contains 0.5 to 20 parts by weight of an antistatic agent per 100 parts by weight of the active energy ray-curable compound. As the antistatic agent, an ionic compound can be preferably used.

The curable composition preferably contains an epoxy compound having at least one epoxy group bonded to an alicyclic ring as an active energy ray curable compound. It is more preferable that the curable composition further contains an oxetane-based compound as an active energy ray-curable compound.

Further, the curable composition may include an (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule as an active energy ray curable compound.

The present invention also provides a liquid crystal display device in which an optical member including a laminate of a polarizing plate and an optical functional layer of the present invention and a polarizing plate or an optical member of the present invention are disposed on one side or both sides of a liquid crystal cell. Examples of the optical function layer include a retardation layer and a brightness enhancement film.

According to the present invention, since the thickness of the protective layer can be reduced as compared with the conventional TAC film or the like, the polarizing plate can be made thinner and lighter, and the adhesion between the polarizing film and the protective layer is also good. In addition, since the hardness of the protective layer is improved, the mechanical strength of the polarizing plate can be improved, and even when the thickness of the protective layer is reduced compared with the conventional one, the shrinkage of the polarizing film under high temperature and high humidity can be effectively suppressed can do. In addition, since the charging by the static electricity can be effectively prevented, the destruction of the liquid crystal driver portion of the liquid crystal display device due to the static electricity can be effectively suppressed. Such a polarizing plate of the present invention and an optical member using the same can be suitably applied to, for example, a liquid crystal display device for mobile use.

<Polarizer>

The polarizing plate of the present invention comprises a polarizing film made of a polyvinyl alcohol-based resin, and a protective layer comprising a cured product of a curable composition containing an active energy ray-curable compound, a polymerization initiator and an antistatic agent laminated on one surface or both surfaces of the polarizing film It has a layer. Hereinafter, the polarizing plate of the present invention will be described in detail.

(Polarizing film)

The polarizing film used in the present invention is made of a polyvinyl alcohol-based resin, and concretely, a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol-based resin film.

The polyvinyl alcohol resin constituting the polarizing film is obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, vinyl ethers and the like. The saponification degree of the polyvinyl alcohol-based resin is usually 85 to 100 mol%, preferably 98 to 100 mol%. The polyvinyl alcohol resin may be further modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The polymerization degree of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, and preferably about 1,500 to 10,000.

Such a polyvinyl alcohol-based resin film is used as the original film of the polarizing film. The method of forming the polyvinyl alcohol-based resin is not particularly limited, and a film can be formed by a known method. The thickness of the original film containing the polyvinyl alcohol-based resin is not particularly limited, but is, for example, about 10 μm to 150 μm.

The polarizing film is produced by a process comprising uniaxially stretching a disc film made of a polyvinyl alcohol-based resin as described above, a process of dyeing a polyvinyl alcohol-based resin film with a dichroic dye and adsorbing the dichroic dye, A step of treating the adsorbed polyvinyl alcohol based 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.

Uniaxial stretching may be performed before or after dyeing with the dichroic dye, or may be performed after dyeing. When uniaxial stretching is performed after dyeing with a dichroic dye, 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 these plural steps. In the uniaxial stretching, the uniaxial stretching may be performed between the different rolls of the main yarn, or may be elongated uniaxially using the heating roll. Further, it may be dry stretching such as stretching in the atmosphere, or wet stretching in which stretching is performed in a state of being swollen with a solvent. The stretching magnification is usually about 4 to 8 times.

In order to dye a polyvinyl alcohol-based resin film with a dichroic dye, for example, a polyvinyl alcohol-based resin film can be dipped in an aqueous solution containing a dichroic dye. As the dichroic dye, iodine, a dichroic dye and the like are used. It is preferable that the polyvinyl alcohol-based resin film is subjected to immersion treatment in water before the dyeing treatment.

When iodine is used as the dichroism dye, a dyeing method is usually employed in which a polyvinyl alcohol resin film is immersed in an aqueous solution containing iodine and potassium iodide. The content of iodine in this aqueous solution is usually about 0.01 to 0.5 parts by weight based on 100 parts by weight of water, and the content of potassium iodide is usually about 0.5 to 10 parts by weight based on 100 parts by weight of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40 占 폚, and the immersion time (dyeing time) in this aqueous solution is usually about 30 to 300 seconds.

On the other hand, when a dichroic dye is used as the dichroic dye, a dyeing method is usually employed in which a polyvinyl alcohol resin film is immersed in an aqueous dye solution containing a water-soluble dichroic dye. The content of the dichroic dye in the dye aqueous solution is usually about 1 × 10 ^-3 to 1 × 10 ^-2 parts by weight based on 100 parts by weight of water. The dye aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing aid. The temperature of the dye aqueous solution is usually about 20 to 80 DEG C, and the immersion time (dyeing time) in the dye aqueous solution is usually about 30 to 300 seconds.

The boric acid treatment after dyeing with the dichroic dye is carried out by immersing the dyed polyvinyl alcohol resin film in an aqueous solution containing boric acid. The content of boric acid in the aqueous solution containing boric acid is usually about 2 to 15 parts by weight, preferably about 5 to 12 parts by weight, based on 100 parts by weight of water. When iodine is used as the dichroic dye, it is preferable that the aqueous solution containing boric acid contains potassium iodide. The content of potassium iodide in the boric acid-containing aqueous solution is usually about 2 to 20 parts by weight, preferably about 5 to 15 parts by weight based on 100 parts by weight of water. The immersing time in the boric acid-containing aqueous solution is usually about 100 to 1,200 seconds, preferably about 150 to 600 seconds, more preferably about 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually 50 ° C or higher, preferably 50 to 85 ° C.

The polyvinyl alcohol resin film after boric acid treatment is usually subjected to water washing treatment. The water washing treatment is carried out, for example, by immersing a boric acid-treated polyvinyl alcohol resin film in water. The temperature of water in the water washing treatment is usually about 5 to 40 占 폚, and the immersion time is about 2 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 drying temperature is usually about 40 to 100 占 폚. The time for the drying treatment is usually about 120 to 600 seconds.

The polarizing film in which the dichromatic dye is adsorbed and oriented on the uniaxially stretched polyvinyl alcohol-based resin film can be produced as described above. The thickness of the polarizing film may be about 5 to 40 mu m.

(Protective layer)

In the present invention, a protective film made of a cured product of a curable composition containing an active energy ray-curable compound, a polymerization initiator and an antistatic agent is laminated on one side or both sides of the polarizing film to form a polarizing plate.

The active energy ray-curable compound contained in the curable composition for forming the protective layer is not particularly limited as long as sufficient adhesion between the polarizing film and the protective layer can be obtained, and examples thereof include a cationic curable compound and a radical curable compound.

As the cationic curing compound, an epoxy compound may be mentioned. Among them, an active energy ray-curable compound is preferably an epoxy-based compound having at least one epoxy group bonded to an alicyclic ring (hereinafter referred to as an alicyclic epoxy compound ) Is preferably used. Here, in the present invention, the "epoxy compound" means a compound having two or more epoxy groups in the molecule and capable of being cured by irradiation with active energy rays. The adhesion between the protective layer and the polarizing film can be further improved by using an epoxy compound.

The epoxy group bonded to the alicyclic ring has a structure represented by the following formula (1). M is an integer of 2 to 5;

Accordingly, the alicyclic epoxy compound is a compound having at least one structure represented by the above-mentioned formula (1) and having two or more epoxy groups in total in the molecule. More specifically, a compound in which one or more hydrogen-removed groups in (CH ₂ ) _m in Chemical Formula 1 is bonded to another chemical structure may be an alicyclic epoxy compound. (CH ₂ ) _m may be appropriately substituted with a straight chain alkyl group such as methyl or ethyl group. Among the alicyclic epoxy compounds, an epoxy compound having an oxabicyclohexane ring (having m = 3 in the formula 1) or an oxabicycloheptane ring (having m = 4 in the formula 1) has an elastic modulus Is high and a protective layer excellent in adhesion with a polarizing film is easily obtained. In the alicyclic epoxy compound, at least one epoxy group bonded to the alicyclic ring may be present, and the remaining epoxy group may not be bonded to the alicyclic ring. Preferably, two or more epoxy groups are all bonded to the alicyclic ring. Hereinafter, the structure of the alicyclic epoxy compound preferably used in the present invention is specifically exemplified, but is not limited to these compounds.

(a) epoxycyclohexylmethyl epoxycyclohexanecarboxylates represented by the following formula (2):

(Wherein R ₁ and R ₂ represent, independently of each other, a hydrogen atom or a straight chain alkyl group of 1 to 5 carbon atoms)

(b) epoxycyclohexanecarboxylates of an alkanediol represented by the following formula (3)

(Wherein R ₃ and R ₄ independently represent a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms, and n represents an integer of 2 to 20)

(c) epoxycyclohexylmethyl esters of dicarboxylic acids represented by the following formula (4):

(Wherein R ₅ and R ₆ independently represent a hydrogen atom or a straight chain alkyl group of 1 to 5 carbon atoms, and p represents an integer of 2 to 20)

(d) epoxycyclohexylmethyl ethers of polyethylene glycol represented by the following formula (5):

(Wherein R ₇ and R ₈ independently represent a hydrogen atom or a straight chain alkyl group of 1 to 5 carbon atoms, and q represents an integer of 2 to 10)

(e) epoxycyclohexyl methyl ethers of alkane diols represented by the following formula (6):

(Wherein R ₉ and R ₁₀ are independently of each other a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms, and r is an integer of 0 to 18)

(f) a diepoxy trispyro compound represented by the following formula (7):

(Wherein R &lt; ₁₁ &gt; and R &lt; ₁₂ &gt; independently represent a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms)

(g) a diepoxy monospiro compound represented by the following formula (8):

(Wherein R &lt; ₁₃ &gt; and R &lt; ₁₄ &gt; each independently represent a hydrogen atom or a straight chain alkyl group of 1 to 5 carbon atoms)

(h) vinylcyclohexene epoxides represented by the following formula (9):

(Wherein R ₁₅ represents a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms)

(i) epoxycyclopentyl ethers represented by the following formula (10):

(Wherein R ₁₆ and R ₁₇ independently represent a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms)

(j) diepoxy tricyclodecane represented by the following formula (11):

(Wherein R ₁₈ represents a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms)

Among the above-exemplified alicyclic epoxy compounds, the following alicyclic epoxy compounds are commercially available, or the like, and are preferably used because they are relatively easy to obtain.

(A) an esterified product of 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid with (7-oxa-bicyclo [4.1.0] hept- Compound of R &lt; ₁ &gt; = R &lt; ₂ &gt; = H]

(B) An ester with 4-methyl-7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and (4-methyl-7-oxa-bicyclo [4.1.0] hept- Cargo [in the formula 2, R ₁ = 4-CH ₃ and R ₂ = 4-CH ₃ ]

(C) an esterified product of 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and 1,2-ethanediol [wherein R ₃ is R ₄ = H, n = 2 ],

(R ₅ = R ₆ = H, p = 4 in the formula (4)] with an adipic acid (D) (7-oxabicyclo [4.1.0] hept-

(E) (4- methyl-7-oxabicyclo [4.1.0] hept-3-yl) methanol in the adipic acid and the esterified product [Chemical Formula _{4, R 5 = 4-CH} 3, R 6 = 4-CH ₃ , p = 4]

(F) (ether compound of 7-oxabicyclo [4.1.0] hept-3-yl) methanol and 1,2-ethanediol [wherein R ₉ = R ₁₀ = H, r = 0 &Lt; / RTI &gt;

In the present invention, the above-mentioned alicyclic epoxy compound is preferably used as the epoxy compound. Other epoxy compounds may be used together with the alicyclic epoxy compound. Examples of other epoxy compounds include hydrogenated epoxy compounds, aliphatic epoxy compounds, and the like.

The hydrogenated epoxy compound can be obtained by subjecting an aromatic epoxy compound to a hydrogenation reaction selectively under pressure in the presence of a catalyst. Examples of the aromatic epoxy compounds include bisphenol-type epoxy resins such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F and diglycidyl ether of bisphenol S; Novolak type epoxy resins such as phenol novolak epoxy resin, cresol novolac epoxy resin and hydroxybenzaldehyde phenol novolac epoxy resin; Glycidyl ethers of tetrahydroxyphenylmethane, glycidyl ethers of tetrahydroxybenzophenone, and epoxy polyvinylphenols, and the like. Among them, glycidyl ether of a bisphenol A hydride is preferably used as the hydrogenated epoxy compound.

Examples of the aliphatic epoxy compound include polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof. More specifically, diglycidyl ether of 1,4-butanediol, diglycidyl ether of 1,6-hexanediol, triglycidyl ether of glycerin, triglycidyl ether of trimethylolpropane, diglycidyl ether of polyethylene glycol (Ethylene oxide, propylene oxide) obtained by adding at least one alkylene oxide (ethylene oxide or propylene oxide) to an aliphatic polyhydric alcohol such as ethylene glycol, propylene glycol, or glycerin, Of polyglycidyl ether, and the like.

In the present invention, it is preferable to mainly use an epoxy compound which does not contain an aromatic ring in the molecule as an epoxy compound from the viewpoints of weatherability, refractive index, cationic polymerizability and the like. The epoxy equivalent of the epoxy compound is usually 30 to 3,000 g / equivalent, preferably 50 to 1,500 g / equivalent. If the epoxy equivalent is small, there is a possibility that the flexibility of the protective layer after curing is lowered and the adhesion with the polarizing film is lowered. On the other hand, if the epoxy equivalent is large, compatibility with other components may be lowered.

When the curable composition used in the present invention contains a cationic curable compound (for example, an alicyclic epoxy compound), the content thereof is preferably 30 to 70% by weight in the total active energy ray-curable compound, By weight to 60% by weight. When the content of the cationic curable compound is small, the adhesiveness with the polarizing film tends to decrease. On the other hand, if the content is large, the optical performance tends to decrease due to the yellowing of the cured film.

When an epoxy compound other than the alicyclic epoxy compound is used, the amount of the other epoxy compound is preferably 30 parts by weight or less based on 100 parts by weight of the epoxy compound. When the amount exceeds 30 parts by weight, the elastic modulus of the cured product is lowered, and the effect of suppressing shrinkage of the polarizing film tends to be lowered.

When the curable composition used in the present invention contains a cationic curable compound such as an epoxy compound, it is preferable that a photo cationic polymerization initiator is blended in the curable composition. When a photo cationic polymerization initiator is used, since it is possible to form a protective layer at room temperature, there is less need to consider the heat resistance of the polarizing film or the distortion due to expansion, and the protective layer can be formed on the polarizing film with good adhesion. Further, since the photo cationic polymerization initiator acts catalytically by light, it is excellent in storage stability and workability even when mixed with an epoxy compound.

The cationic cationic polymerization initiator generates a cationic species or Lewis acid by irradiation with an active energy ray such as visible light, ultraviolet ray, X-ray or electron beam to initiate the polymerization reaction of the epoxy group. In the present invention, any type of photo cationic polymerization initiation system can be used. Specific examples thereof include, for example, onium salts such as aromatic diazonium salts, aromatic iodonium salts and aromatic sulfonium salts, iron- .

Examples of the aromatic diazonium salt include benzene diazonium hexafluoroantimonate, benzene diazonium hexafluorophosphate, and benzene diazonium hexafluoroborate.

Examples of the aromatic iodonium salt include diphenyl iodonium tetrakis (pentafluorophenyl) borate, diphenyl iodonium hexafluorophosphate, diphenyl iodonium hexafluoroantimonate, di (4-nonylphenyl) iodonium hexafluorophosphate, and the like.

Examples of the aromatic sulfonium salt include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, 4,4'-bis [di 4,4'-bis [di (? - hydroxyethoxy) phenylsulfonio] diphenylsulfide bis hexafluoroantimonate, 4,4'-bis [ Di (p-toluyl) sulfonium] -2-isopropylthioquinoxaline, bis (4-hydroxyphenyl) diphenylsulfide bishexafluorophosphate, (Pentafluorophenyl) borate, 4-phenylcarbonyl-4'-di (pentafluorophenyl) borate, and 2-isopropylthioxanthone tetrakis Phenylsulfonio-diphenylsulfide hexafluorophosphate, 4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfone-diphenylsulfide hexa (P-tert-butylphenylcarbonyl) -4'-di (p-toluyl) sulfonio-diphenylsulfide tetrakis (pentafluorophenyl) borate, and the like. have.

Examples of the iron-arene complexes include xylene-cyclopentadienyl iron (II) hexafluoroantimonate, cumene-cyclopentadienyl iron (II) hexafluorophosphate, xylene-cyclopentadienyl iron (II) -Tris (trifluoromethylsulfonyl) methanide, and the like.

These photo cationic polymerization initiators can be easily obtained from commercial products. For example, "Kayarad PCI-220", "Kayarad PCI-620" (manufactured by Nippon Kayaku Co., Ltd.) CI-5102 &quot;), &quot; Adeka Optomer SP-170 &quot; (manufactured by Adeka Co., Ltd.) DPI-101 "and" DPI-2064S "(all manufactured by Nihon Soda Co., Ltd.)," CIT-1370 "," CIT-1682 "," CIP- 102, "" DPI-103 "," DPI-105 "," MPI-103 "," MPI-105 "," BBI-101 "," BBI- , "TPS-101", "TPS-102", "TPS-103", "TPS-105", "MDS- PI-2074 "(manufactured by Rhodia)," UVACURE 1590 "(manufactured by Daicel-Cotech), and the like.

These photo cationic polymerization initiators may be used alone or in combination of two or more. Of these, aromatic sulfonium salts are preferably used because they have an ultraviolet ray absorption property in a wavelength region of 300 nm or more and are therefore excellent in curability and can provide a cured product having good mechanical strength and good adhesion with a polarizing film .

The mixing amount of the photo cationic polymerization initiator is usually 0.5 to 20 parts by weight, preferably 1 to 6 parts by weight, based on 100 parts by weight of the cationic curable compound. If the blending amount of the photo cationic polymerization initiator is too small, the curing becomes insufficient and the mechanical strength and adhesion between the protective layer and the polarizing film tend to be lowered. If the blending amount of the photo cationic polymerization initiator is too large, there is a possibility that the durability performance of the obtained polarizing plate is lowered.

When an epoxy compound is used as the cationic curable compound, an oxetane compound may be added to the curable composition. By adding an oxetane-based compound, the viscosity of the curable composition can be lowered and the curing rate can be increased. In addition, the yellowing of the cured film can be blocked to improve the optical performance.

The oxetane-based compound is a compound having a 4-membered ring ether structure in the molecule, and examples thereof include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl Benzene, 3-ethyl-3- (phenoxymethyl) oxetane, di [(3-ethyl-3-oxetanyl) methyl] ether, , Phenol novolak oxetane, and the like. These oxetane compounds can be easily obtained from commercial products, and examples thereof include "AARON oxetane OXT-101", "AARON oxetane OXT-121", "AARON oxetane OXT-211" Oxetane OXT-221 "and" AARON oxetane OXT-212 "(all manufactured by Toagosei Co., Ltd.).

The blending amount of the oxetane-based compound is not particularly limited, but is usually 5 to 30% by weight, preferably 10 to 25% by weight, of the total active energy ray-curable compound.

Next, the radical curable compound will be described. As the radical curable compound, it is preferable to use a (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule. By using the (meth) acrylic compound, the mechanical strength of the protective layer can be improved. Among them, it is more preferable to use a (meth) acrylic compound having a modulus of elasticity of 3000 MPa or more as a cured product obtained by curing alone. The modulus of elasticity of the cured product obtained by solely curing the (meth) acrylic compound is more preferably 3100 MPa or more. (Meth) acrylic compound having a modulus of elasticity of not less than 3000 MPa of the cured product obtained by curing can provide a protective layer capable of suppressing shrinkage of the polarizing film more effectively with higher hardness and mechanical strength. The term "(meth) acryloyloxy group" means an acryloyloxy group or a methacryloyloxy group. The term "(meth) acrylic compound" means an acrylate ester derivative or a methacrylate ester derivative, respectively.

The modulus of elasticity of the cured product obtained by curing the (meth) acrylic compound alone is measured as follows. First, a composition containing a (meth) acrylic compound and a radical polymerization initiator and not containing other active energy ray-curable compounds is coated on a polyethylene terephthalate film (PET film), and light irradiation is performed to cure the composition. Next, this cured layer is cut into a length of 1 cm width x 8 cm for each PET film, and a PET film is peeled to obtain a sample. Subsequently, both ends in the longitudinal direction of the sample were sandwiched between upper and lower gripping mechanisms of an AUTOGRAPH AG-1S tester manufactured by Shimadzu Seisakusho Co., Ltd. so that the interval between gripping mechanisms was 5 cm, and the web was stretched at a tensile speed of 10 mm / , And the elastic modulus is calculated from the slope of the initial straight line in the obtained stress-strain curve.

The radical-curable compound can be polymerized and cured by irradiation with active energy rays such as ultraviolet rays, visible rays, electron beams and X-rays in the presence of a photo radical polymerization initiator.

Examples of the (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule include (meth) acrylate monomers having at least one (meth) acryloyloxy group in the molecule (Meth) acryloyloxy group-containing compounds such as (meth) acrylate oligomers having two or more (meth) acryloyloxy groups in the molecule (hereinafter referred to as (meth) acrylate oligomer) have. These may be used alone, or two or more of them may be used in combination. The term "(meth) acrylate monomer" means an acrylate monomer or methacrylate monomer, and the term "(meth) acrylate oligomer" means an acrylate oligomer or a methacrylate oligomer, respectively.

Examples of the (meth) acrylate monomer include (meth) acrylate monomers having one (meth) acryloyloxy group in the molecule (hereinafter referred to as monofunctional (meth) acrylate monomers) (Meth) acrylate monomer having an acryloyloxy group (hereinafter referred to as a bifunctional (meth) acrylate monomer) and a (meth) acrylate monomer having at least three (meth) acryloyloxy groups in the molecule Referred to as a polyfunctional (meth) acrylate monomer). (Meth) acrylate monomers may be used alone or in combination of two or more.

Specific examples of monofunctional (meth) acrylate monomers include tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2- (Meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, isobutyl (meth) acrylate, t- (Meth) acrylate, dicyclopentenyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, phenoxyethyl (Meth) acrylate, pentaerythritol mono (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, pentaerythritol mono It can be given.

As the monofunctional (meth) acrylate monomer, a carboxyl group-containing (meth) acrylate monomer may also be used. Examples of the monofunctional (meth) acrylate monomer containing a carboxyl group include 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxyethylhexahydrophthalic acid, carboxyethyl (meth) Methacryloyloxyethyl succinic acid, N- (meth) acryloyloxy-N ', N'-dicarboxy-p-phenylenediamine and 4- (meth) acryloyloxyethyltrimellitic acid. . As the monofunctional (meth) acrylate monomer, a monomer containing a (meth) acryloylamino group such as 4- (meth) acryloylamino-1-carboxymethylpiperidine and the like may also be used.

Examples of the bifunctional (meth) acrylate monomers include alkylene glycol di (meth) acrylates, polyoxyalkylene glycol di (meth) acrylates, halogen-substituted alkylene glycol di (meth) acrylates, aliphatic polyols Di (meth) acrylates of dicyclohexylenediene or tricyclodecanedialanol, di (meth) acrylates of dioxane glycol or dioxanedialanol, bisphenol A or bis Di (meth) acrylates of an alkylene oxide adduct of bisphenol F, and epoxy di (meth) acrylates of bisphenol A or bisphenol F, but the present invention is not limited thereto and various ones can be used.

More specific examples of the bifunctional (meth) acrylate monomers include ethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) (Meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylol propane di (meth) acrylate, pentaerythritol di (meth) acrylate, Acrylate, diethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (Meth) acrylate, poly (ethylene glycol) di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (Meth) acryloyloxyethoxyethoxyphenyl] propane, 2,2-bis [4- (meth) acryloyloxy (meth) acrylate, (Meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, 1,3-dioxane-2,5-diyl di (meth) acrylate, hydrogenated dicyclopentadienyl (2-hydroxy-1,1-dimethylethyl) -5-ethyl-hexanediol di (meth) acrylate, which is an acetal compound of hydroxypropylaldehyde and trimethylolpropane (trade name: dioxane glycol di Di (meth) acrylate and tris (hydroxyethyl) isocyanurate di (meth) acrylate of 5-hydroxymethyl-1,3-dioxane.

Examples of the polyfunctional (meth) acrylate monomer include glycerin tri (meth) acrylate, trimethylol propane tri (meth) acrylate, ditrimethylol propane tri (meth) acrylate, ditrimethylol propane tetra (Meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa Poly (meth) acrylates of trifunctional or higher aliphatic polyols such as trimethylolpropane tri (meth) acrylate, poly (meth) acrylates of trifunctional or higher halogen substituted polyols, tri (meth) acrylates of alkylene oxide adducts of glycerin, Acrylate, tri (meth) acrylate of an alkylene oxide adduct of trimethylolpropane, 1,1,1-tris [(meth) (Meth) acryloyloxyethoxyethoxy] propane, and tris (hydroxyethyl) isocyanurate tri (meth) acrylates.

Examples of the (meth) acrylate oligomer include a bifunctional or higher urethane (meth) acrylate oligomer (hereinafter referred to as a polyfunctional urethane (meth) acrylate oligomer), a bifunctional or higher polyester (meth) acrylate oligomer (Meth) acrylate oligomer having a bifunctionality or more (hereinafter referred to as a polyfunctional epoxy (meth) acrylate oligomer), and the like. (Meth) acrylate oligomer may be used alone or in combination of two or more.

Examples of the polyfunctional urethane (meth) acrylate oligomer include urethane reaction products of a (meth) acrylate monomer having at least one (meth) acryloyloxy group and a hydroxyl group in the molecule and a polyisocyanate, polyisocyanates And (meth) acrylate monomers each having at least one (meth) acryloyloxy group and at least one hydroxyl group in the molecule, and the like.

Examples of the (meth) acrylate monomer having at least one (meth) acryloyloxy group and at least one hydroxyl group in the molecule used in the urethanization reaction include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (Meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, glycerin di (Meth) acrylate, dipentaerythritol penta (meth) acrylate, and the like.

Examples of the polyisocyanate used in the urethanization reaction include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and aromatic isocyanates in these diisocyanates. Diisocyanates obtained by hydrogenation (for example, diisocyanates such as hydrogenated tolylene diisocyanate and hydrogenated xylylene diisocyanate), di- or triisocyanates such as triphenylmethane triisocyanate and dimethyl tinphenyl triisocyanate, and And polyisocyanates obtained by mass-increasing diisocyanate.

As the polyols to be provided for the reaction with the polyisocyanate, besides aromatic, aliphatic and alicyclic polyols, polyester polyols, polyether polyols and the like can be used. Examples of the aliphatic and alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, ditrimethylol Propylene, pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, hydrogenated bisphenol A, and the like.

The polyester polyol is obtained by a dehydration condensation reaction between the polyol and a polybasic carboxylic acid or an anhydride thereof. Examples of the polybasic carboxylic acid or its anhydride include succinic anhydride, adipic acid, maleic anhydride, itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, hexahydro (anhydrous) phthalic acid , (Anhydrous) phthalic acid, isophthalic acid, and terephthalic acid.

Examples of the polyether polyols include polyoxyalkylene-modified polyols obtained by reacting the polyols or dihydroxybenzenes with alkylene oxides in addition to polyalkylene glycols.

Further, the polyfunctional polyester (meth) acrylate oligomer can be obtained by a dehydration condensation reaction of (meth) acrylic acid, a polybasic carboxylic acid or anhydride thereof and a polyol. Examples of the polybasic carboxylic acid or its anhydride used in the dehydration condensation reaction include succinic acid, adipic acid, (maleic anhydride) maleic acid, (anhydride) itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, Hexahydro (anhydrous) phthalic acid, (anhydrous) phthalic acid, isophthalic acid, terephthalic acid and the like. Examples of the polyol used in the dehydration condensation reaction include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, Ditrimethylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, hydrogenated bisphenol A, and the like.

Further, the polyfunctional epoxy (meth) acrylate oligomer can be obtained by an addition reaction of polyglycidyl ether and (meth) acrylic acid. Examples of the polyglycidyl ether include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, bisphenol A diglycidyl ether And the like.

Among the above-mentioned (meth) acrylic compounds, for example, the (meth) acrylic compound having the structure represented by the following general formula (12) or (13) has a modulus of elasticity of not less than 3000 MPa and a cationic curing compound , In particular, is excellent in adhesion with a polarizing film when it is combined with an alicyclic epoxy compound.

In the general formulas (12) and (13), R ₁₉ and R ₂₀ independently represent a (meth) acryloyloxy group or a (meth) acryloyloxyalkyl group. When R ₁₉ or R ₂₀ is a (meth) acryloyloxyalkyl group, the alkyl may be straight-chain or branched and may have 1 to 10 carbon atoms, and generally about 1 to 6 carbon atoms is sufficient. In Formula 13, R ₂₁ is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and the hydrocarbon group may be linear or branched, and typically may be an alkyl group. The alkyl group in this case generally has about 1 to 6 carbon atoms.

The compound represented by the formula (12) is a di (meth) acrylate derivative of hydrogenated dicyclopentadiene or tricyclodecanedialcohol, and specific examples thereof include those exemplified above, but hydrogenated dicyclopentadienyldi (meth) acrylate [in the formula _{12, R 19 = R 20 =} ( meth) compounds of the acryloyloxy group-acryloyl], tricyclodecane dimethanol di (meth) in the acrylate formula _{12, R 19 = R 20 =} ( meth) acrylate Butyloxymethyl group], and the like.

In addition, the compound represented by the formula (13) is a di (meth) acrylate derivative of dioxane glycol or dioxane dialkanol, and specific examples thereof include those exemplified above, but 1,3-dioxane-2,5- meth) acrylate [alias: dioxane glycol di (meth) acrylate, R ₁₉ = in the general formula 13 R ₂₀ = (meth) acryloyloxy group of acrylic, R ₂₁ = compound of H], hydroxy Sangapi aldehyde and trimethylolpropane (Meth) acrylate of an acetal compound of propane with a chemical name of 2- (2-hydroxy-1,1-dimethylethyl) -5-ethyl-5-hydroxymethyl-1,3- in the formula 13, and the like R ₁₉ = (meth) acryloyloxyethyl group, R ₂₀ = 2- (meth) acryloyloxy-1,1-dimethyl-ethyl group, R ₂₁ = ethyl group in the compound].

When the curable composition used in the present invention contains a radical-curable compound (for example, a (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule) Is preferably 30 to 70% by weight, more preferably 35 to 65% by weight, and particularly preferably 40 to 60% by weight. When the content of the radical curable compound is small, the optical performance tends to decrease due to the yellowing of the cured film, and if it is large, the adhesion with the polarizing film tends to be lowered.

When the curable composition used in the present invention contains a radical-curable compound, it is preferable that the photo-radical polymerization initiator is blended in the curable composition. The photo radical polymerization initiator is not particularly limited as long as it can initiate curing of the radical curable compound by irradiation with an active energy ray and conventionally known ones can be used. Specific examples of the photoradical polymerization initiator include, but are not limited to, acetophenone, 3-methylacetophenone, benzyldimethylketal, 1- (4-isopropylphenyl) -2-hydroxy- Methyl-1- [4- (methylthio) phenyl-2-morpholinopropane-1-one, 2-hydroxy-2-methyl- Acetophenone based initiators; Benzophenone initiators including benzophenone, 4-chlorobenzophenone, and 4,4'-diaminobenzophenone; Benzoin ether initiators including benzoin propyl ether, benzoin ethyl ether; Thioxanthone initiators including 4-isopropylthioxanthone; Xanthone, fluorenone, camphorquinone, benzaldehyde, anthraquinone, and the like.

The blending amount of the photo radical polymerization initiator is usually 0.5 to 20 parts by weight, preferably 1 to 6 parts by weight, based on 100 parts by weight of the radical curable compound. If the blending amount of the photo radical polymerization initiator is small, the curing becomes insufficient, and the mechanical strength and adhesion of the protective layer and the polarizing film tend to be lowered. If the compounding amount of the photo radical polymerization initiator is too large, there is a possibility that the durability performance of the obtained polarizing plate is lowered.

In the present invention, the curable composition preferably contains both of an epoxy compound and (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule as an active energy ray curable compound. Among them, the curable composition is preferably a combination of an alicyclic epoxy compound as an active energy ray curable compound and a (meth) acrylic compound having at least one (meth) acryloyloxy group in a molecule having a modulus of elasticity of not less than 3000 MPa of a cured product obtained by curing It is more preferable to include both of them. By using both the epoxy compound as the active energy ray-curable compound and the (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule, the viscosity and the curing rate of the curable composition and the surface hardness It is possible to more easily adjust the adhesion with the polarizing film and the elastic modulus, and it is possible to obtain a protective layer which is excellent in hardness and mechanical strength and can effectively suppress the shrinkage of the polarizing film under high temperature and high humidity. In addition, it becomes possible to provide a polarizing plate which can impart high adhesion to the protective layer and is excellent in heat and humidity resistance.

Acrylate compound having at least one (meth) acryloyloxy group in the molecule in the total amount of these compounds when the epoxy compound and the (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule are used in combination Methacrylic compound is preferably 30 to 70% by weight, more preferably 35 to 65% by weight, and particularly preferably 40 to 60% by weight. When the content is low, the shrinkage percentage of the polarizing plate may become large. If the content is large, the adhesion between the polarizing film and the protective layer may not be sufficient.

Next, the antistatic agent will be described. In the present invention, the antistatic agent is contained in the curable composition used for forming the protective layer. As a result, the antistatic agent is dispersed in the protective layer made of the cured product of the curable composition, so that electrification of the protective layer can be prevented. By providing the protective layer with an antistatic function, for example, when a peeling film adhered to the surface of a pressure-sensitive adhesive layer provided on a protective layer is peeled off or a polarizing plate is adhered to the liquid crystal cell through a pressure-sensitive adhesive layer provided on the protective layer, It is possible to prevent static electricity from being charged when the polarizing plate is peeled off, and it is possible to effectively suppress destruction of the liquid crystal driver portion of the liquid crystal display device due to static electricity.

As a technique for preventing the protection layer from being charged, a method of forming a resin cured film (antistatic layer) containing an antistatic agent on a protective film such as a triacetyl cellulose film is known (see, for example, Patent Document 6 ), This method has a two-layer structure of a protective film and an antistatic layer, so that there is a limit to making the polarizing plate thinner. On the other hand, in the present invention, since the antistatic agent is dispersed in the protective layer itself made of the cured composition of the curable composition, the antistatic layer is provided with the antistatic function, so that it is not necessary to provide the antistatic layer separately. Therefore, according to the present invention, it is possible to further reduce the thickness and weight of the polarizing plate. Further, by employing a cured product of a curable composition containing an antistatic agent as a protective layer, the provision of the antistatic function to the protective layer and the thinning of the polarizing plate accompanying the elimination of the antistatic layer, It is possible to simultaneously reduce the thickness of the polarizing film, improve the adhesion with the polarizing film, improve the hardness of the protective layer, and improve the shrinking restraining force of the polarizing film.

The antistatic agent is not particularly limited, and examples thereof include ionic compounds, conductive fine particles, and conductive polymers. Examples of the ionic compound include an ionic compound having an organic cation and an ionic compound having an inorganic cation.

Examples of the ionic compound having an organic cation include 1-butylpyridinium tetrafluoroborate, 1-butylpyridinium hexafluorophosphate, 1-butyl-3-methylpyridinium tetrafluoroborate, 3-methylpyridinium bis (trifluoromethanesulfonyl) imide, 1-butyl-3-methylpyridinium bis (pentafluoroethanesulfonyl) ) Imide, 1-butyl-4-methylpyridinium hexafluorophosphate, 1-hexylpyridinium tetrafluoroborate, 1-hexylpyridinium hexafluorophosphate, 1-octylpyridinium hexafluorophosphate, Ethyl indole tetrafluoroborate, 1-ethyl indole tetrafluoroborate, 1-ethylcarbazole tetrafluoroborate, 1-ethyl indole tetrafluoroborate, 2-methyl indole tetrafluoroborate, -3-methylimidazolium tetrafluoroborate, 1- Ethyl-3-methylimidazolium trifluoroacetate, 1-ethyl-3-methylimidazolium heptafluorobutyrate, 1-ethyl-3-methylimidazolium Ethyl-3-methylimidazolium bis (trifluoromethanesulfonate), 1-ethyl-3-methylimidazolium perfluorobutanesulfonate, 1-ethyl- Ethyl-3-methylimidazolium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-3-methylimidazolium tris (trifluoromethanesulfonyl) imide, Butyl imidazolium methanesulfonate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1- Butyl-3-methylimidazolium trifluoroacetate, 1-butyl-3-methylimidazolium heptafluorobutyrate, 1-butyl- Butyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-hexyl-3-methyl Imidazolium bromide, 1-hexyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1- 3-methylimidazolium trifluoromethanesulfonate, 1-octyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium hexafluorophosphate, 1-hexyl- Dimethylimidazolium tetrafluoroborate, 1,2-dimethyl-3-propylimidazolium bis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium hexafluorophosphate, Ethyl-3-methylimidazolium-p-toluenesulfonate, 1-methylpyrazolium tetrafluoroborate, 3-methylpyrazolium tetrafluoride Butylborate, 1-butyl-1-methylpyrrolidinium hexafluorophosphate, tetrabutylammonium hexafluorophosphate, tetrabutylammonium-p-toluenesulfonate, tetrahexylammonium bis (trifluoromethanesulfonyl) imide , N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis ( (Trifluoromethanesulfonyl) imide, diallyldimethylammonium tetrafluoroborate, diallyldimethylammonium trifluoromethanesulfonate, diallyldimethylammonium bis (trifluoromethanesulfonyl) imide, diallyldimethylammonium Bis (pentafluoroethanesulfonyl) imide, glycidyltrimethylammonium trifluoromethanesulfonate, glycidyltrimethylammonium bis (trifluoromethanesulfonyl) imide, glycidyltrimethylammonium bis (pentafluoro Rosulfosulfonyl) imide, 1-butylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-butyl-3-methylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-ethyl- (Trifluoromethanesulfonyl) trifluoroacetamide, diallyldimethylammonium (trifluoromethanesulfonyl) trifluoroacetamide, glycidyltrimethylammonium (trifluoromethanesulfonyl) trifluoroacetate, (Trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-butylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl- (Trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-hexylammonium bis (trifluoromethylsulfonyl) imide, N-dimethyl-N-ethyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N, N-dimethyl-N, N-dipropylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl- N, N-dimethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl- N-dimethyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N- N-dimethyl-N-butyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl- (Trifluoromethanesulfonyl) imide, N, N-dimethyl-N, N-dihexylammonium bis (trifluoromethanesulfonyl) imide, trimethylheptylammonium bis Trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl- N, N-diethyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl- (Trifluoromethanesulfonyl) imide, N, N-diethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, triethylpropyl (Trifluoromethanesulfonyl) imide, triethylpentylammonium bis (trifluoromethanesulfonyl) imide, triethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, Propyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl- , N, N-dipropyl-N-butyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N, N-dihexylammonium bis (trifluoromethanesulfonyl) N, N-dibutyl-N-methyl-N-pentyl N, N-dibutyl-N-methyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, trioctylmethylammonium bis (trifluoromethanesulfonyl) imide Propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, (2-hydroxyethyl) imide, Trimethylammonium bis (trifluoromethanesulfonyl) imide, (2-hydroxyethyl) trimethylammonium dimethylphosphinate, and the like.

Examples of the ionic compound having an inorganic cation include lithium bromide, lithium iodide, lithium tetrafluoroborate, lithium hexafluorophosphate, lithium thiocyanate, lithium perchlorate, lithium trifluoromethanesulfonate, lithium bis ( Lithium bis (trifluoromethanesulfonyl) imide, lithium bis (pentafluoroethanesulfonyl) imide, lithium tris (trifluoromethanesulfonyl) methide and the like.

Examples of the conductive fine particles include conductive inorganic particles such as antimony-doped tin oxide, phosphorus-doped tin oxide, antimony oxide, zinc antimonate, titanium oxide, zinc oxide and ITO (Indium Tin Oxide) .

Examples of the conductive polymer include polyaniline, polypyrrole, polyacetylene, and polythiophene.

Of the above-mentioned antistatic agents, ionic compounds are preferably used because they are excellent in compatibility with active energy ray-curable compounds, more preferably ionic compounds having organic cations, and ionic compounds having organic cations It is more preferable to use an onium-based compound.

These antistatic agents may be used alone or in combination of two or more. Examples of the antistatic agent are not limited to those listed above.

Since it is preferable that the protective layer is optically transparent, it is preferable to use an antistatic agent that does not hinder optical transparency of the protective layer without causing light scattering.

The antistatic agent is preferably added in an amount of 0.5 to 20 parts by weight, more preferably 2 to 15 parts by weight, and still more preferably 4 to 10 parts by weight, per 100 parts by weight of the active energy ray-curable compound contained in the curable composition. Parts by weight. If the amount of the antistatic agent added is small, the antistatic property of the protective layer may not be sufficient. On the other hand, if the addition amount of the antistatic agent is too large, the adhesion between the polarizing film and the protective layer may be deteriorated. Further, since the optimal amount of the antistatic agent is different depending on the kind of use the charging type of the agent, or active energy ray-curable compound, the addition amount within the above range, the surface resistance of the protective layer to be described later to be 1.0 × 10 ¹³ Ω / □ or less .

The curable composition may contain a leveling agent, if necessary, in addition to an active energy ray-curable compound, an antistatic agent, and a polymerization initiator. When the curable composition is applied to a polarizing film or a substrate and the coating property on the polarizing film or the substrate is insufficient or the surface property of the cured composition of the curable composition is poor, . As the leveling agent, various compounds such as a silicone type, a fluorine type, a polyether type, an acrylic acid copolymer type and a titanate type can be used. These leveling agents may be used alone or in combination of two or more.

The leveling agent is preferably added in an amount of 0.01 to 1 part by weight, more preferably 0.1 to 0.7 part by weight, and still more preferably 0.2 to 0.5 part by weight, based on 100 parts by weight of the active energy ray-curable compound contained in the curable composition Wealth. When the amount of the leveling agent to be added is small, improvement in coatability and surface properties may not be sufficient. If the amount of the leveling agent added is too large, the adhesion between the polarizing film and the protective layer may be deteriorated.

Further, the curable composition may further contain a photosensitizer, if necessary. By using the photosensitizer, the reactivity of the cationic polymerization and / or the radical polymerization of the active energy ray-curable compound is improved, so that the mechanical strength of the protective layer and the adhesion between the protective layer and the polarizing film can be improved. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfates, redox compounds, azo and diazo compounds, halogen compounds, and photoreducing pigments. Specific photosensitizers include, for example, benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether, and?,? -Dimethoxy-? -Phenylacetophenone; Benzophenone derivatives such as benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4'-bis (dimethylamino) benzophenone and 4,4'-bis (diethylamino) benzophenone; Thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone; Anthraquinone derivatives such as 2-chloro anthraquinone and 2-methyl anthraquinone; Acridone derivatives such as N-methyl acridone, N-butyl acridone; Other examples include, but are not limited to,?,? - diethoxyacetophenone, benzyl, fluorenone, xanthone, uranyl compounds, and halogen compounds. These may be used alone or in combination of two or more.

The photosensitizer is preferably contained in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the active energy ray-curable compound.

A known polymer additive commonly used in polymer materials may be added to the active energy ray-curable resin composition. Examples of the ultraviolet absorber include ultraviolet absorbers such as primary antioxidants such as phenol type and amine type, secondary antioxidants such as sulfur type, hindered amine type light stabilizers (HALS), benzophenone type, benzotriazole type and benzoate type. have.

In addition, the curable composition may contain a solvent as required. The solvent is appropriately selected depending on the solubility of the components constituting the curable composition. Commonly used solvents include aliphatic hydrocarbons such as n-hexane and cyclohexane; Aromatic hydrocarbons such as toluene and xylene; Alcohols such as methanol, ethanol, propanol, isopropanol and n-butanol; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; Esters such as methyl acetate, ethyl acetate and butyl acetate; Cellosolve such as methyl cellosolve, ethyl cellosolve, butyl cellosolve; And halogenated hydrocarbons such as methylene chloride and chloroform. The compounding ratio of the solvent is appropriately determined in terms of the viscosity of the desired curable composition in consideration of processability such as film forming property.

Examples of the method for forming the protective layer containing the antistatic agent on one side or both sides of the polarizing film include the following methods. First, the curable composition is coated on a base material such as a polyethylene terephthalate film (PET film), for example. Subsequently, after drying for removing the solvent as necessary, a base material having a coating film containing the curable composition is bonded to the polarizing film so that the coating film side becomes a bonding surface. At this time, when a protective layer containing an antistatic agent is laminated on both sides of the polarizing film, two substrates having a coating film are prepared, and the two substrates are bonded to both surfaces of the polarizing film. Next, the laminate is irradiated with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, or heated to cure the coating film containing the curable composition to form a protective layer. Finally, the substrate is peeled off to obtain a polarizing plate having a protective layer containing an antistatic agent on one side or both sides of the polarizing film. The thickness of the protective layer containing an antistatic agent is preferably as thin as possible in view of thinness and light weight, but if the thickness is too thin, the polarizing film can not be sufficiently protected and the handling property is insufficient. Therefore, the thickness of the protective layer containing the antistatic agent is preferably about 1 to 35 mu m.

It is also possible to form the protective layer directly on the polarizing film and cure it. However, when the curable composition contains a solvent and is cured through a drying process, the polarizing film may be eroded into a solvent or shrunk The above-mentioned method is preferable. When a protective layer containing an antistatic agent is formed on both sides of the polarizing film, the components contained in the curable composition for forming both protective layers may be the same or different.

When a protective layer containing an antistatic agent is formed on only one side of the polarizing film, the other side of the polarizing film may be provided with a protective layer containing no antistatic layer (for example, the protective layer containing no antistatic agent, A protective layer comprising a cured product of the same curing composition as the composition, and a conventionally known protective film such as a triacetyl cellulose film) may be laminated, or a protective layer may not be provided.

When the coating film containing the curable composition is cured by irradiation of an active energy ray, the light source used is not particularly limited, but it is preferable to use a light source having a light emission distribution at a wavelength of 400 nm or less such as a low pressure mercury lamp, a medium pressure mercury lamp, A mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, and a metal halide lamp. The light irradiation intensity to the curable composition may be different depending on the composition, but it is preferable that the irradiation intensity in the wavelength range effective for activation of the photo radical polymerization initiator and / or the photo cation polymerization initiator is 10 to 2500 mW / cm 2. If the irradiation intensity to the curable composition is less than 10 mW / cm 2, the reaction time becomes too long. When the irradiation intensity exceeds 2500 mW / cm 2, heat radiated from the lamp and heat generated during polymerization of the curable composition, There is a possibility of causing deterioration of the semiconductor device. The light irradiation time to the curable composition is controlled for each composition, and is not particularly limited, but is preferably set so that the integrated light quantity expressed as a product of irradiation intensity and irradiation time is 10 to 2500 mJ / cm 2. If the amount of accumulated light in the curable composition is too small, the generation of active species derived from the polymerization initiator is not sufficient, and the curing of the obtained protective layer may be insufficient. If the accumulated light amount is too large, the irradiation time becomes long, which is disadvantageous for the productivity improvement. The irradiation of the active energy ray is preferably performed within a range in which various performances such as the polarization degree and transmittance of the polarizing film are not deteriorated.

The protective layer containing the antistatic agent obtained as described above has a surface resistance value of 1.0 × 10 ¹³ Ω / □ or less, preferably 2.0 × 10 ¹² Ω / □ or less under the conditions of 23 ° C. and 55% RH, And more preferably 5.0 x 10 &lt; ¹¹ &gt; If the surface resistance value is large, there is a high possibility of destroying the liquid crystal driver portion of the liquid crystal display device when peeling off the release film on the pressure-sensitive adhesive layer or peeling the polarizing plate from the liquid crystal cell. The surface resistance value of the protective layer containing the antistatic agent can be controlled by adjusting the amount of the antistatic agent to an appropriate amount in consideration of the type of the antistatic agent used, the kind of the active energy ray-curable compound, and the like.

<Optical member and liquid crystal display device>

The optical member of the present invention includes a laminate of the polarizing plate and the optical functional layer, and more specifically, the optical functional layer is provided on the protective layer of the polarizing plate. The optical functional layer is not particularly limited and conventionally known ones can be used. Concrete examples of the optical function layer include, for example, a reflection layer, a transflective reflective layer, a light diffusion layer, a retardation layer, a condenser, and a luminance enhancement film.

The reflective layer can be formed, for example, by providing a foil or a vapor-deposited film containing a metal such as aluminum on a protective layer of a polarizing plate. The semi-transmissive reflective layer can be formed by making the reflective layer a half mirror, or containing a pearl pigment or the like, and providing a reflective plate exhibiting light transmittance on the protective layer. The light-diffusing layer can be formed by a method of performing a matting treatment on the protective layer, a method of applying a resin containing fine particles, a method of adhering a film containing fine particles, and the like.

The retardation layer is used for the purpose of compensating the retardation by the liquid crystal cell. For example, a birefringent film made of stretched films of various plastics, a film in which discotic liquid crystals or nematic liquid crystals are aligned and fixed, And the above-mentioned liquid crystal layer is formed. In this case, a cellulose-based film such as triacetylcellulose is preferably used as a film base for supporting the aligned liquid crystal layer.

The light-collecting plate is used for the purpose of optical path control or the like, and can be formed as a prism array sheet, a lens array sheet, a dot-laid sheet, or the like.

The brightness enhancement film is used for the purpose of improving the brightness in a liquid crystal display device or the like. Examples of such a brightness enhancement film include a reflection type polarized light separating sheet designed to laminate a plurality of thin film films having different anisotropy of refractive index so as to produce anisotropy in reflectance, An orientation film of a liquid crystal polymer or a circularly polarized light separation sheet on which the oriented liquid crystal layer is supported on a film base.

The optical functional layer may be used alone or in combination of two or more. Bonding of the optical functional layer to the protective layer and bonding of the optical functional layers can be performed using an adhesive or a pressure-sensitive adhesive.

The polarizing plate or optical member of the present invention can be preferably applied to a liquid crystal display device. At this time, the polarizing plate or optical member of the present invention is disposed on one or both surfaces of the liquid crystal cell. The polarizing plates or optical members provided on both sides of the liquid crystal cell may be the same or different.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, &quot; part (s) &quot; and &quot;% &quot; representing amounts used or contents are by weight unless otherwise specified.

(Production Example 1: Production of polarizing film)

A polyvinyl alcohol film having an average degree of polymerization of about 2400, a degree of saponification of 99.9 mol% or more and a thickness of 75 탆 was immersed in pure water at 30 캜 and immersed in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.02 / Respectively. Then, it was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 12/5/100 at 56.5 ° C. Subsequently, the film was washed with pure water at 8 占 폚 and then dried at 65 占 폚 to obtain a polarizing film (thickness 30 占 퐉) in which iodine was adsorbed and oriented on polyvinyl alcohol. The stretching was carried out mainly in a step of iodine dyeing and boric acid treatment, and the total stretching magnification was 5.3 times.

(Production Example 2: Production of antistatic agent-containing curing composition I)

First, the following components were mixed to obtain a curing composition A.

35 parts of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (Celloxide 2021P, manufactured by Daicel Chemical Industries, Ltd.)

15 parts of bis (3-ethyl-3-oxetanylmethyl) ether (AARON oxetane OXT-221, manufactured by Toagosei Co., Ltd.)

50 parts of tricyclodecane dimethanol diacrylate (A-DCP, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

2.5 parts of 2-hydroxy-2-methyl-1-phenylpropan-1-one (DAROCURE 1173, a photoradical polymerization initiator manufactured by Ciba Specialty Chemicals)

2.5 parts of 4,4'-bis [diphenylsulfonio] diphenyl sulfide bishexafluorophosphate-based photo cationic polymerization initiator (manufactured by Daicel Scientific Co., Ltd., Yuba Cure 1590)

Next, 100 parts of the curable composition A and 4 parts of the aliphatic amine based ionic compound (a) shown below as an antistatic agent were mixed to obtain an antistatic agent-containing curable composition I.

(Preparation Example 3: Preparation of antistatic agent-containing curing composition II)

An antistatic agent-containing curable composition II was obtained in the same manner as in Production Example 2, except that the amount of the aliphatic amine-based ionic compound (a) was changed to 6 parts.

(Production Example 4: Preparation of antistatic agent-containing curing composition III)

An antistatic agent-containing curable composition III was obtained in the same manner as in Preparation Example 2, except that the amount of the aliphatic amine-based ionic compound (a) was changed to 10 parts.

(Production Example 5: Preparation of antistatic agent-containing curing composition IV)

An antistatic agent-containing curing composition IV was obtained in the same manner as in Production Example 2, except that 4 parts of the aliphatic amine-based ionic compound (b) shown below was used in place of the aliphatic amine-based ionic compound (a).

(Preparation Example 6: Preparation of antistatic agent-containing curing composition V)

An antistatic agent-containing curing composition V was obtained in the same manner as in Production Example 2, except that 6 parts of the aliphatic amine-based ionic compound (b) was used instead of the aliphatic amine-based ionic compound (a).

&Lt; Example 1 >

The antistatic agent-containing curable composition I obtained in Production Example 2 was coated on a polyethylene terephthalate (PET) film (Ester Film E5100, manufactured by Toyobo Co., Ltd.) using Bar Coater # 7. Then, two PET films having the coated film containing the curable composition were bonded to both surfaces of the polarizing film obtained in Production Example 1 using a bonding apparatus (LPA3301, manufactured by Fuji Plastics Co., Ltd.) such that the coated film side was a bonding surface. Next, ultraviolet rays were irradiated to the laminate with a D-valve manufactured by Fusion UV System Company at an accumulated light quantity of 1500 mJ / cm &lt; 2 &gt; to cure both sides of the coated film. Finally, the PET film on both sides was peeled off to obtain a polarizing plate having a protective layer (protective film) having a thickness of 12 占 퐉 and having a protective function on both surfaces of the polarizing film. The thickness of the polarizing plate was measured using a film thickness meter (ZC-101, manufactured by Nikon Corporation) to be 54 탆. (The thickness of the polarizing plate or polarizing film was also measured box).

&Lt; Examples 2 to 5 >

Polarizing plates were prepared in the same manner as in Example 1 except that the antistatic agent-containing curable compositions II to V obtained in Production Examples 3 to 6 were used in place of the antistatic agent-containing curable composition I.

&Lt; Comparative Example 1 &

A polarizing plate was produced in the same manner as in Example 1 except that the curable composition A (not containing an antistatic agent) was used in place of the antistatic agent-containing curable composition I.

&Lt; Comparative Example 2 &

A protective film comprising triacetyl cellulose (TAC) having a thickness of 80 占 퐉 was bonded to both sides of a polarizing film (thickness 30 占 퐉) in which iodine was adsorbed and oriented on a polyvinyl alcohol resin film, and an antistatic layer (SRH862AP8-LT4-S / 81-GS, manufactured by Sumitomo Chemical Co., Ltd.) was used.

&Lt; Comparative Example 3 &

The polarizing film obtained in Production Example 1 was used alone.

The polarizers of Examples 1 to 5 and Comparative Example 1 were tested for adhesion between the protective layer and the polarizing film. The polarizing plate of Examples 1 to 5 and Comparative Examples 1 to 2 and the polarizing film of Comparative Example 3 were evaluated for antistatic property. The results are shown in Table 1.

The measurement method of each test is as follows.

[Adhesion test]

After attaching the polarizing plate to the glass through a pressure-sensitive adhesive, 100 scratch scales of 1 mm each side were cut with a cutter knife on the surface of the protective layer, scotch tape was stuck thereon and then peeling test was carried out. The number of grid marks remaining was counted. As a result, the number of grid marks remaining in any of the polarizing plates was 100 pieces. In Table 1, &quot; A &quot; indicates that the number of remaining grid squares is 100/100.

[Evaluation of antistatic property]

The obtained surface resistivity of the polarizing plate was measured under the conditions of 23 캜 and 55% RH using a surface intrinsic resistivity meter ("Hirest-up MCP-HT450" (trade name), manufactured by Mitsubishi Chemical Corporation) The sex was evaluated. The antistatic property was evaluated immediately after the polarizing plate (polarizing film in Comparative Example 3) was produced.

It is to be understood that the embodiments and examples disclosed herein are not to be considered in all respects as illustrative and not restrictive. It is intended that the scope of the invention be indicated by the appended claims rather than the foregoing description, and that all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Claims (10)

A polarizing plate having a protective layer on at least one surface of a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol based resin film, Wherein the protective layer comprises a cured product of a curable composition containing an active energy ray-curable compound containing an epoxy compound having two or more epoxy groups in a molecule, a polymerization initiator, and an antistatic agent comprising an ionic compound, The surface resistance value of the protective layer is 10 ¹³ ? /? Or less, The antistatic agent is an ionic compound having an organic cation, Wherein the curable composition comprises 0.5 to 20 parts by weight of the antistatic agent per 100 parts by weight of the active energy ray curable compound. delete The curable composition according to claim 1, wherein the curable composition is an active energy ray curable compound which comprises an epoxy compound having at least one epoxy group bonded to an alicyclic ring and having at least one (meth) acryloyloxy group in the molecule (Meth) acrylic compound, wherein the (meth) acrylic compound contains at least one of compounds having a structure represented by the following formula (12) or (13). &Lt; Formula 12 >

&Lt; Formula 13 >

(Wherein, R ₁₉ and R ₂₀ are independently (meth) represents an aryloxy group as a acryloyloxy group or a (meth) acrylate wherein the carbon number of the alkyl is from 1 to 10, R ₂₁ is hydrogen or C 1 -C each other 10 &lt; / RTI &gt; hydrocarbon group) The polarizing plate according to claim 1, wherein the curable composition comprises the epoxy compound having at least one epoxy group bonded to an alicyclic ring as the active energy ray curable compound. The polarizing plate according to claim 4, wherein the curable composition further comprises an oxetane-based compound as the active energy ray-curable compound. The polarizing plate according to claim 4, wherein the curable composition further comprises a (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule as the active energy ray curable compound. An optical member comprising the laminate of the polarizing plate and the optical functional layer according to claim 1. 8. The optical member according to claim 7, wherein the optical functional layer is a retardation layer. The optical member according to claim 7, wherein the optical function layer is a brightness enhancement film. A liquid crystal display device comprising the polarizing plate according to claim 1 or an optical member including a laminate of the polarizing plate and the optical functional layer is disposed on one side or both sides of the liquid crystal cell.