KR20150143866A - Polarizing plate, optical member, and liquid crystal display device - Google Patents

Abstract

The present invention provides a polarizing film comprising a polarizing film in which a dichromatic dye is adsorbed and oriented on a polyvinyl alcohol based resin film and a protective layer comprising a cured product of a curable resin composition containing an active energy ray curable compound formed on at least one side of the polarizing film Wherein the active energy ray curable compound contains a compound having at least one epoxy group in the molecule and a (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule, and the modulus of elasticity of the protective layer is A polarizing plate having a thickness of from 3300 to 10000 MPa, an optical member using the same, and a liquid crystal display device, while maintaining good adhesion between the polarizing film and the protective layer, Is provided.

Description

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

The present invention relates to a polarizing plate having a protective layer on one side or both sides of a polarizing 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 made of 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. As such a transparent resin film, triacetylcellulose film (TAC film) is widely used 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 necessary and inserted into the liquid crystal display device.

BACKGROUND ART [0002] Recent developments in mobile devices such as notebook personal computers, mobile phones, car navigation systems and the like of liquid crystal displays have demanded a thinner, lighter, and durable (high mechanical strength) polarizing plate constituting a liquid crystal display device. Further, in a liquid crystal display for mobile use, it is desired that the liquid crystal display device can be used even under humid heat, and a polarizing plate used therefor is required to have high humidity and heat resistance. However, when the polarizing plate is conventionally exposed to high humidity, Or the polarizing film shrinks. Therefore, it is required that the protective layer laminated on the polarizing film is made thin and lightweight, and at the same time, it has a high hardness to improve the mechanical strength and the ability to suppress the shrinkage of the polarizing film (shrinkage restraining force).

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 占 퐉 or less from the viewpoints of handling and durability at the time of working.

As a technique capable of solving the above problems, Japanese Patent Application Laid-Open No. 2000-199819 (Patent Document 1) discloses a method 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 And the like. Further, Japanese Unexamined Patent Application Publication No. 2003-185842 (Patent Document 2) discloses a method of curing an energy ray-curable composition containing an energy ray polymerizable compound having a dicyclopentyl residue or a dicyclopentenyl residue, A protective film is formed on the substrate. Japanese Patent Application Laid-Open No. 2004-245924 (Patent Document 3) discloses a polarizing plate having a protective film composed mainly of an epoxy resin on at least one surface of a polarizing film. Japanese Patent Laid-Open Publication No. 2005-92112 (Patent Document 4) discloses that at least one surface of a polarizing film is protected with a cured product of an active energy ray-curable resin composition.

Japanese Patent Application Laid-Open No. 2000-199819 Japanese Patent Laying-Open No. 2003-185842 Japanese Patent Application Laid-Open No. 2004-245924 Japanese Patent Application Laid-Open No. 2005-92112

An object of the present invention is to provide a polarizing plate which is thin and lightweight and has an improved hardness of a protective layer while maintaining good adhesion between the polarizing film and the protective layer. Another object of the present invention is to provide an optical member and a liquid crystal display device using such a polarizing plate.

The polarizing plate of the present invention comprises a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, and a protective film formed on at least one side of the polarizing film and comprising a cured product of a curable resin composition containing an active energy ray- Wherein the active energy ray curable compound contains a compound having at least one epoxy group in the molecule and a (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule, and the active energy ray- And a modulus of elasticity of 3300 to 10000 MPa.

In the polarizing plate of the present invention, it is preferable that 10 to 70 parts by weight of the (meth) acrylic compound is contained in 100 parts by weight of the active energy ray curable compound.

In the polarizing plate of the present invention, it is preferable that the above-mentioned (meth) acrylic compound provides a cured product comprising only the (meth) acrylic compound and the polymerization initiator having an elastic modulus of 3000 MPa or more.

In the polarizing plate of the present invention, it is preferable that the (meth) acrylic compound contains at least one of the compounds represented by the following general formulas (1) to (4).

Wherein Q ₁ and Q ₂ independently represent a (meth) acryloyloxy group or a (meth) acryloyloxyalkyl group, wherein the number of carbon atoms in the alkyl group is from 1 to 10; , R represents hydrogen or a hydrocarbon group of 1 to 10 carbon atoms, T ¹ , T ² and T ³ independently represent a (meth) acryloyloxy group, and T represents a hydroxyl group or (Meth) acryloyloxy group)

In the polarizing plate of the present invention, it is preferable that the curable resin composition further contains an oxetane-based compound.

In the polarizing plate of the present invention, it is preferable that the curable resin composition further contains fine particles. In this case, it is more preferable that the curable resin composition contains 5 to 250 parts by weight of fine particles per 100 parts by weight of the active energy ray curable compound.

In the polarizing plate of the present invention, it is preferable that the fine particles are silica particles having a particle diameter of 100 nm or less. In this case, it is more preferable that the fine silica particles have at least one functional group selected from the group consisting of a hydroxyl group, an epoxy group, a (meth) acryloyloxy group and a vinyl group on the surface thereof.

In the polarizing plate of the present invention, the thickness of the protective layer is preferably 1 to 35 mu m.

The present invention also provides an optical member including the polarizing plate of the present invention and the laminated body of the optical functional layer. The optical functional layer in the optical member of the present invention is preferably any one of a retardation layer, a brightness enhancement film, and a surface treatment layer.

The present invention also provides a liquid crystal display device in which the above-mentioned polarizing plate of the present invention or the above-described optical member of the present invention is disposed on one side or both sides of a liquid crystal cell.

According to the present invention, since the thickness of the protective layer can be reduced as compared with a 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, not only the mechanical strength of the polarizing plate can be improved but also the shrinkage of the polarizing film under high temperature and high humidity can be effectively suppressed even when the thickness of the protective layer is reduced . 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.

1 (A) and 1 (B) show a sample 1 before immersion in hot water and a sample 1 after immersion in hot water, respectively. Fig. 1 ).
<Description of Symbols>
1: sample
2: area where no polarizing film exists between protective films
3: the part where the color of the periphery of the polarizing plate is missing
4: Shrinked polarizing film
5:

<Polarizer>

The polarizing plate of the present invention comprises a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, and a protection comprising a cured resin composition containing an active energy ray-curable compound formed on one side or both sides of the polarizing film Layer is provided. In the polarizing plate of the present invention, the active energy ray-curable compound used in this protective layer is preferably a compound having at least one epoxy group in the molecule and (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule And the elastic modulus of the protective layer is 3300 to 10000 MPa. In the present specification, "modulus of elasticity" means tensile modulus at room temperature (about 23 ° C) unless otherwise specified. Hereinafter, the polarizing plate of the present invention will be described in detail.

The polarizing film used in the present invention is made of a polyvinyl alcohol-based resin, and specifically, 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 a copolymer of vinyl acetate and other monomers copolymerizable therewith, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate. 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 about 85 to 100 mol%, preferably 98 to 100 mol%. The polyvinyl alcohol-based resin may be further modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually about 1000 to 10000, and preferably about 1500 to 10000.

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 can be carried out by a known method. The thickness of the original film made of a polyvinyl alcohol-based resin is not particularly limited, but is, for example, about 10 to 150 mu m.

The polarizing film is usually prepared by a process comprising the steps of uniaxially stretching a original 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 to adsorb 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.

The uniaxial stretching may be performed before or after dyeing with the dichroic dye, or may be performed after the dyeing. In the case where 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, stretching may be performed uniaxially between rolls having different main ratios, or may be stretched uniaxially using a heat roll. It may also be a dry stretching method such as stretching in air or a wet stretching method in which stretching is performed in a state of being swollen with a solvent. The draw ratio 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 may be immersed in an aqueous solution containing a dichroic dye. As the dichroic dye, iodine, dichromatic dye and the like are used. The polyvinyl alcohol-based resin film is preferably subjected to immersion treatment in water before the dyeing treatment.

In the case of using iodine as the dichroic dye, a dyeing method usually involves immersing the polyvinyl alcohol resin film 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 method of dipping the polyvinyl alcohol-based resin film in an aqueous dye solution containing a water-soluble dichroic dye is generally employed as a dyeing method. 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 占 폚, 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 boric acid-containing aqueous solution 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 further contains potassium iodide. The content of potassium iodide in the boric acid-containing aqueous solution is usually about 2 to 20 parts by weight, and 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 1200 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.

After the boric acid treatment, the polyvinyl alcohol-based resin film is usually washed with water. 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.

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

(Protective layer)

In the present invention, a polarizing plate is formed by laminating a protective layer comprising a cured product of a curable resin composition containing an active energy ray-curable compound on one side or both sides of the polarizing film. The active energy ray-curable compound in the present invention is a compound having at least one epoxy group in the molecule (hereinafter, simply referred to as an "epoxy compound") and a (meth) acrylate having at least one (meth) acryloyloxy group in the molecule (Hereinafter, simply referred to as "(meth) acrylic compound").

Here, the elastic modulus of the protective layer is 3300 to 10000 MPa, preferably 3500 to 8000 MPa. When the modulus of elasticity of the protective layer is less than 3300 MPa, the ability to suppress the shrinkage of the polarizing film under high temperature and high humidity is lowered, and as a result, the polarization characteristics are deteriorated. When the elastic modulus of the protective layer exceeds 10000 MPa, the adhesion between the polarizing film and the protective layer deteriorates, so that problems such as peeling of the protective layer may occur.

Further, it is preferable that the protective layer is made so that the elastic modulus at a high temperature of about 80 캜 is not too low, in particular, in order to suppress the shrinkage of the polarizing film under high temperature conditions. Specifically, it is preferable that the storage elastic modulus at 80 캜 is in the range of 1500 to 5500 MPa. In addition, when it is difficult to accurately measure the sample length before and after the test, it is difficult to measure the tensile modulus at a high temperature of about 80 캜. In this case, the tensile modulus Which is a concept similar to that of the conventional method.

By containing an epoxy compound in the curable resin composition, it is possible to obtain a protective layer exhibiting good adhesion to a polarizing film and a retardation film, and having excellent durability with excellent transparency, mechanical strength, thermal stability, moisture barrier property and the like. In the present invention, the term "compound having at least one epoxy group in the molecule" refers to a compound having at least one epoxy group in the molecule and is used for irradiation of active energy rays (e.g., ultraviolet rays, visible rays, &Lt; / RTI &gt; Further, epoxy compounds, (meth) acrylic compounds and oxetane compounds to be described later are generally referred to as "active energy ray curable compounds &quot;.

The epoxy compound is not particularly limited, but an epoxy compound which does not contain an aromatic ring in the molecule is preferable from the viewpoints of weatherability, refractive index, cationic polymerizability and the like. Examples of the epoxy compound not containing an aromatic ring in the molecule include a hydrogenated epoxy compound, an aliphatic epoxy compound, and an alicyclic epoxy compound.

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 bispale F and diglycidyl ether of bisphenol S; Novolak type epoxy resins such as phenol novolak epoxy resin, cresol novolak epoxy resin and hydroxybenzaldehyde phenol novolac epoxy resin; Glycidyl ether of tetrahydroxyphenylmethane, glycidyl ether of tetrahydroxybenzophenone, epoxy polyvinyl phenol and the like, and the like. Among them, glycidyl ether of hydrogenated bisphenol A is preferable as the hydrogenated epoxy compound.

Examples of the aliphatic epoxy compounds 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 or propylene oxide) obtained by adding at least one alkylene oxide (ethylene oxide or propylene oxide) to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol and glycerin, Polyglycidyl ether, and the like.

The alicyclic epoxy compound means an epoxy compound having at least one epoxy group bonded to an alicyclic ring. The "epoxy group bonded to alicyclic ring" has a structure obtained by removing one or more hydrogen from (CH ₂ ) _m from the following formula. M is an integer of 2 to 5;

Therefore, the alicyclic epoxy compound is a compound having at least one structure represented by the above formula in the molecule. More specifically, the compound represented by the above formula, or the compound in which the group of the structure in which one or plural hydrogen atoms are removed from (CH ₂ ) _m in the above chemical formula is bonded to a group having a different chemical structure may be an alicyclic epoxy compound have. (CH ₂ ) _m may be appropriately substituted with a straight chain alkyl group such as a methyl group or an ethyl group.

Of the above epoxy compounds, alicyclic epoxy compounds, that is, compounds in which at least one of the epoxy groups is bonded to an alicyclic ring is preferable, and oxabicyclohexane rings (those having m = 3 in the above formula) The epoxy compound having a cycloheptane ring (in the formula, m = 4) is more preferably used since it has a high modulus of elasticity of the cured product and is easy to obtain a protective layer excellent in adhesion to a polarizing film. 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 (I):

(I)

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

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

&Lt;

(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 (III):

(III)

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

(d) epoxycyclohexyl methyl ethers of polyethylene glycol represented by the following formula (IV):

(IV)

(Wherein R ⁷ and R ⁸ independently represent a hydrogen atom or a straight chain alkyl group having 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 (V):

(V)

(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 2 to 20)

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

&Lt; Formula (VI)

(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 (VII):

(VII)

(Wherein R ¹³ and R ¹⁴ represent, independently of each other, a hydrogen atom or a straight chain alkyl group having 1 to 5 carbon atoms)

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

&Lt; Formula (VIII)

(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 general formula (IX):

<Formula IX>

(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 (X):

(X)

(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 preferably used because they are commercially available or are analogous to them and are relatively easy to obtain.

(A) 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid from (7-oxabicyclo [4.1.0] hept-3-yl) esters of the methanol formula I, R ¹ = R &lt; ² &gt; = H]

(B) An esterified product of 4-methyl-7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and (4-methyl- A compound wherein R ¹ = 4-CH ₃ and R ² = 4-CH ₃ in the formula (I)

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

(D) (ester compound of 7-oxabicyclo [4.1.0] hept-3-yl) methanol and adipic acid [compound of formula III, R ⁵ = R ⁶ = H, p = 4]

(E) (4- methyl-7-oxabicyclo [4.1.0] hept-3-yl) methanol and sub-adipic acid esters of the formula ^{III, R 5 = 4-CH} 3, R 6 = 4- CH ₃ , p = 4]

(F) (7- oxabicyclo [4.1.0] hept-3-yl) ether product of methanol and 1,2-ethanediol [in formula ^{V, R 9 = R 10 =} H, r = 2] The compound .

In the present invention, each epoxy compound may be used alone or in combination with at least one other epoxy compound.

In the curable resin composition used in the present invention, the epoxy compound is contained preferably in a proportion of 30 to 90 parts by weight, more preferably 35 to 80 parts by weight, in 100 parts by weight of the active energy ray- , And more preferably 40 to 70 parts by weight. When the content of the epoxy compound is less than 30 parts by weight, the adhesion between the polarizing film and the protective layer tends to be lowered. When the content exceeds 90 parts by weight, the optical performance tends to decrease due to the yellowing of the protective layer as a cured product.

The curable resin composition may contain an oxetane-based compound in addition to the epoxy compound. By adding the oxetane-based compound, the viscosity of the curable resin composition can be lowered and the curing rate can be increased. Further, it is possible to prevent yellowing of the protective layer which is a cured product, and to improve the optical performance.

The oxetane compound is a compound having at least one oxetane ring (4-membered ring ether) in the molecule, and examples thereof include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis [ (3-ethyl-3-oxetanyl) methyl] ether, 3-ethyl-3- Hexyloxymethyl) oxetane, phenol novolac oxetane, and the like. These oxetane compounds are commercially available and can be easily obtained, and examples thereof include "Aromon oxetane OXT-101", "Aromon oxetane OXT-121", "Aromon 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 30 parts by weight or less, preferably 10 to 25 parts by weight, based on 100 parts by weight of the active energy ray-curable compound.

When the curable resin composition used in the present invention contains a cationic curable compound such as an epoxy compound or an oxetane-based compound, it is preferable that a photo cationic polymerization initiator is blended in the curable resin composition. When a photo cationic polymerization initiator is used, it becomes possible to form a protective layer at room temperature. Therefore, it is necessary 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 with light, it is excellent in storage stability and workability even when mixed with the curable resin composition.

The cationic photopolymerization initiator is capable of generating 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 polymerization reaction of an epoxy compound and / or an oxetane-based compound. In the present invention, any type of photo cationic polymerization initiator may be used, and examples thereof include, but are not limited to, onium salts such as aromatic diazonium salts, aromatic iodonium salts and aromatic sulfonium salts, iron- have.

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.

The aromatic sulfonium salts include, for example, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, 4,4'-bis [ 4,4'-bis [di (? - hydroxyethoxy) phenylsulfonio] diphenylsulfide bis hexafluoroantimonate, 4,4'-bis , 4'-bis [di (? - hydroxyethoxy) phenylsulfonio] diphenyl sulfide bishexafluorophosphate, 7- [di (p- tolyl) sulfonio] -2-isopropylthio (Pentafluorophenyl) borate, 4-phenylcarbonyl-4'-fluorophenylboronate, octanoic acid hexafluoroantimonate, 7- [di (p- tolyl) sulfonio] -2-isopropylthioxanthone tetrakis Diphenylsulfone hexafluorophosphate, 4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfone-diphenylsulfide Diphenylsulfide tetrakis (pentafluorophenyl) borate, and the like can be used as the starting material for the positive electrode active material, such as hexafluoroantimonate and 4- (p-tert-butylphenylcarbonyl) -4'-di (p- .

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

These photo cationic polymerization initiators can be easily obtained commercially. For example, "Kayarad PCI-220", "Kayarad PCI-620" (manufactured by Nippon Kayaku Co., Ltd.) CI-5102 " and "CIT-6990" (manufactured by Union Carbide Corp.), "ADEKA OPTOMER SP-150", "ADEKA OPTOMER SP- DPI-101 "," DPI-102 "and" CIP-2064S "(all manufactured by Nippon Soda Co., Ltd.) DPI-103, DPI-105, MPI-103, MPI-105, BBI-101, BBI-102, BBI- 103, "" TPS-105 "," MDS-103 "," MDS-105 "," DTS-102 "," DTS- "PI-2074" (manufactured by Rhodia), "UVACURE 1590" (manufactured by Daicel Cytech), and the like.

Each of these photo cationic polymerization initiators may be used alone or in combination with one or more kinds of them. Among them, an aromatic sulfonium salt is preferably used because it has an ultraviolet ray absorption property in a wavelength region of 300 nm or more, and thus can provide a cured product having excellent curability and good adhesion with a polarizing film.

The compounding amount of the photo cationic polymerization initiator is generally 0.5 to 20 parts by weight, preferably 1 to 6 parts by weight, based on 100 parts by weight of the total amount of the cationic curable compound such as an epoxy compound and an oxetane compound. If the blending amount of the photo cationic polymerization initiator is less than 0.5 part by weight based on 100 parts by weight of the total amount of the epoxy compound and the oxetane-based compound, the curing becomes insufficient and the mechanical strength and adhesion between the protective layer and the polarizing film tend to be lowered. When the compounding amount of the photo cationic polymerization initiator is more than 20 parts by weight based on 100 parts by weight of the total amount of the cationic curable compound, the ionic substances in the cured product are increased to increase the hygroscopicity of the cured product, .

The curable resin composition used for forming the protective layer may contain at least one (meth) acryloyloxy group in the molecule and at least one (meth) acryloyloxy group in the molecule which is simultaneously subjected to the radical polymerization of the epoxy compound and the oxetane- (Meth) acryl-based compound. (Meth) acrylic compound, a protective layer having high hardness, excellent mechanical strength, and high durability can be obtained. Further, by containing the (meth) acrylic compound, it becomes possible to more easily adjust the viscosity and curing rate of the curable resin composition, the surface curability of the resulting protective layer, and the adhesion with the polarizing film.

As the (meth) acrylic compound in the present invention, a compound having a (meth) acryloyl group and a cured product comprising only a polymerization initiator provides an elastic modulus of 3000 MPa or more (preferably, 3100 MPa or more) . When a (meth) acrylic compound having a modulus of elasticity of less than 3000 MPa of a compound having a (meth) acryloyl group and a polymerization initiator alone is used, the mechanical strength of the protective film is insufficient and the shrinkage of the polarizing film can not be suppressed Because.

The term "(meth) acryloyloxy group" as used herein means a methacryloyloxy group or an acryloyloxy group. The term "(meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule" means a compound having at least one methacryloyloxy group or acryloyloxy group in the molecule and having Quot; means a methacrylic acid ester derivative or an acrylate ester derivative that can be cured by irradiation with active energy rays (e.g., ultraviolet rays, visible rays, electron beams, X-rays, etc.).

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 such as a (meth) acryloyl oligomer having a (meth) acryloyloxy group in the molecule and a (meth) acrylate oligomer having at least two Containing compound. Each of these may be used alone or in combination with at least one other. The term "(meth) acrylate monomer" means an acrylate monomer or a methacrylate monomer, and the term "(meth) acrylate oligomer" means an acrylate oligomer or a methacrylate oligomer, respectively.

Examples of the (meth) acrylate monomers include (meth) acrylate monomers having one (meth) acryloyloxy group in the molecule (hereinafter referred to as "monofunctional (meth) acrylate monomers"), (Meth) acryloyloxy monomer having three or more (meth) acryloyloxy groups in the molecule (hereinafter referred to as " bifunctional (meth) acrylate monomer & (Hereinafter referred to as "polyfunctional (meth) acrylate monomers"). (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, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (Meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, isobutyl (meth) (Meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, phenoxyethyl (meth) acrylate, (Meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, ethylcarbitol (meth) acrylate, trimethylolpropane mono Acrylate, phenoxypol And the like can be mentioned ethylene glycol (meth) acrylate.

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, monomers 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) Di (meth) acrylates of polyhydric alcohols, di (meth) acrylates of polyols, di (meth) acrylates of hydrogenated dicyclopentadiene or tricyclodecanedialanol, di (meth) acrylates of dioxane glycol or dioxanedialanol, Di (meth) acrylates of alkylene oxide adducts of bisphenol F, and epoxy di (meth) acrylates of bisphenol A or bisphenol F, but are 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) Acrylates such as hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane di 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, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di Bis [4- (meth) acryloyloxyethoxyethoxyphenyl] propane, 2,2-bis [4- (meth) acryloyloxyethoxy (Meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, 1,3-dioxane-2,5-diyl di (meth) acrylate, hydrogenated dicyclopentadienyl [Chemical name: 2- (2-hydroxy-1,1-dimethylethyl) -5-ethyl-5- (ethylamino) Di (meth) acrylate of 1,3,5-tris (hydroxymethyl-1,3-dioxane) and di (meth) acrylate of 1,3,5-tris (2-hydroxyethyl) isocyanurate.

Examples of trifunctional or higher polyfunctional (meth) acrylate monomers include glycerin tri (meth) acrylate, trimethylol propane tri (meth) acrylate, ditrimethylol propane tri (meth) acrylate, ditrimethylol propane tetra Acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol tetra (Meth) acrylates of trifunctional or higher functional aliphatic polyols such as tri (meth) acrylate, and 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) Ethoxy] ethoxy on reels one oxy-propane, 1,3,5-tris (2-hydroxyethyl) isocyanurate tri (meth) acrylates, silicone hexa (meth) acrylate.

Examples of the (meth) acrylate oligomer include a urethane (meth) acrylate oligomer, a polyester (meth) acrylate oligomer, and an epoxy (meth) acrylate oligomer. (Meth) acrylate oligomer may be used alone or in combination of two or more.

The urethane (meth) acrylate oligomer is a compound having a urethane bond (-NHCOO-) and at least two (meth) acryloyloxy groups in the molecule. Specifically, a urethane-forming reaction product of a (meth) acrylate monomer and a polyisocyanate each having at least one (meth) acryloyloxy group and at least one hydroxyl group in a molecule, or a terminal isocyanate obtained by reacting a polyol with a polyisocyanate Group-containing urethane compound and a (meth) acrylate monomer each having at least one (meth) acryloyloxy group and at least one hydroxyl group in the molecule.

Examples of the hydroxyl group-containing (meth) acrylate monomers used in the urethanization reaction include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) (Meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (pentaerythritol tri (meth) acrylate, pentaerythritol tri Methacrylate, and the like.

Examples of the polyisocyanate used in the urethane formation reaction with such a hydroxyl group-containing (meth) acrylate monomer include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, tolylene diisocyanate, Isocyanates, diisocyanates obtained by hydrogenating aromatic isocyanates in these diisocyanates (for example, diisocyanates such as hydrogenated tolylene diisocyanate and hydrogenated xylylene diisocyanate), triphenylmethane triisocyanate, dimethylentriphenyl Di- or triisocyanates such as triisocyanate and dibenzylbenzene triisocyanate, and polyisocyanates obtained by mass-increasing diisocyanate.

Examples of the polyols used for forming the terminal isocyanate group-containing urethane compound by the reaction with the polyisocyanate include aromatic polyols, polyether polyols and the like in addition to aromatic, aliphatic and alicyclic polyols. 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 condensation reaction between the polyol and a polybasic carboxylic acid or anhydride thereof. Examples of the polybasic carboxylic acid or its anhydride include succinic acid, adipic acid, (maleic 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 polyether polyols include polyoxyalkylene-modified polyols obtained by the reaction of the polyols or dihydroxybenzenes with alkylene oxides in addition to polyalkylene glycols.

Polyester (meth) acrylate oligomer is a compound having an ester bond in the molecule and at least two (meth) acryloyloxy groups. Specifically, it can be obtained by a 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 condensation reaction include succinic acid, adipic acid, maleic 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 condensation reaction include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, Trimethylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, hydrogenated bisphenol A, and the like.

The epoxy (meth) acrylate oligomer can be obtained by an addition reaction of polyglycidyl ether and (meth) acrylic acid, and has at least two (meth) acryloyloxy groups in the molecule. Examples of the polyglycidyl ether used in the addition reaction 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 (meth) acrylic compounds, it is preferable to use at least one (meth) acrylic compound represented by the following general formulas (1) to (4) in view of excellent both adhesion and elasticity.

&Lt; Formula 1 >

(2)

(3)

&Lt; Formula 4 >

In the general formulas (1) and (2), Q ₁ and Q ₂ independently represent a (meth) acryloyloxy group or a (meth) acryloyloxyalkyl group. When Q ₁ or Q ₂ is a (meth) acryloyloxyalkyl group, the alkyl may be linear or branched and has 1 to 10 carbon atoms, and usually about 1 to 6 carbon atoms is sufficient. In the general formula (2), R is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and the hydrocarbon group may be branched or branched, and typically may be an alkyl group. The alkyl group in this case generally has about 1 to 6 carbon atoms. In the general formula (3), T ₁ , T ₂ and T ₃ independently represent a (meth) acryloyloxy group. In the general formula (4), T represents a hydroxyl group or a (meth) acryloyloxy group.

The compound represented by the formula (1) is a di (meth) acrylate derivative of hydrogenated dicyclopentadiene or tricyclodecanedialcohol, and specific examples thereof include hydrogenated dicyclopentadienyldi (meth) acrylate in formula _1, Q 1 = Q ₂ = (meth) acryloyloxy group of compound acryloyl], tricyclodecane dimethanol di (meth) acrylate in the formula _1, Q 1 = Q ₂ = when yloxy a (meth) acrylic Methyl group] and the like.

The compound represented by the general formula (2) is a di (meth) acrylate derivative of dioxane glycol or dioxane dialkanol. Specific examples thereof include 1,3-dioxane-2,5-diyl di (meth) rate [alias: dioxane glycol di (meth) acrylate, in the formula _{2, Q 1 = Q 2 =} ( meth) compound of acryloyloxy group with an acrylic, R = H], hydroxypiperidine acetal feet aldehyde and trimethylolpropane (Meth) acrylate of the compound [chemical name: 2- (2-hydroxy-1,1-dimethylethyl) -5-ethyl-5-hydroxymethyl-1,3- ₁ = (meth) acryloyloxymethyl group, Q ₂ = 2- (meth) acryloyloxy-1,1-dimethylethyl group and R = ethyl group].

The compound represented by the general formula (3) is triacrylate or trimethacrylate of 1,3,5-tris (2-hydroxyethyl) isocyanurate, as also exemplified above.

The compound represented by the general formula (4) is a tri- or tetra- (meth) acrylate of pentaerythritol. Specific examples thereof include pentaerythritol tri (meth) acrylate and pentaerythritol tetra Acrylate.

In the curable resin composition for use in the present invention, the (meth) acrylic compound is preferably 10 to 70 parts by weight, more preferably 20 to 65 parts by weight, and most preferably 30 to 60 parts by weight, in 100 parts by weight of the active energy ray- Particularly desirable. When the content of the (meth) acrylic compound is less than 10 parts by weight, the shrinkage percentage of the polarizing plate may become large. When the content of the (meth) acrylic compound exceeds 70 parts by weight, the adhesion between the polarizing film and the protective layer may be insufficient.

When the curable resin composition contains a radically polymerizable compound such as the (meth) acrylic compound described above, it is preferable that a photo radical polymerization initiator is blended. As the photo radical polymerization initiator, any known photo radical polymerization initiator may be used as far as it can initiate polymerization of a radical polymerizable compound such as a (meth) acrylic compound by irradiation with an active energy ray. Specific examples of the photoradical polymerization initiator include acetophenone, 3-methylacetophenone, benzyldimethylketal, 1- (4-isopropylphenyl) -2-hydroxypropyl- - an acetophenone-based initiator including [4- (methylthio) phenyl-2-morpholinopropane-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1- 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; Other examples include 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 polymerizable compound such as a (meth) acrylic compound. If the blending amount of the photo radical polymerization initiator is less than 0.5 parts by weight based on 100 parts by weight of the radical polymerizable compound, the curing becomes insufficient and the mechanical strength and adhesion of the protective layer and the polarizing film tend to be lowered. When the blending amount of the photo radical polymerization initiator is more than 20 parts by weight based on 100 parts by weight of the (meth) acrylic compound, there is a possibility that the durability of the resulting polarizing plate is lowered.

The curable resin composition used in the present invention may further contain fine particles. When the curable resin composition contains fine particles, the hardness and mechanical strength of the obtained protective layer can be further improved. Thus, the ability to suppress the shrinkage of the polarizing film under high temperature and high humidity can be further enhanced. Examples of the fine particles include inorganic fine particles, organic fine particles, and inorganic / organic hybrid fine particles. Since it is preferable that the protective layer is optically transparent, it is preferable to use those that do not inhibit the optical transparency of the protective layer, such as not causing light scattering.

The inorganic fine particles are not particularly limited, and examples thereof include metal oxide fine particles such as fine silica particles, alumina fine particles, tin oxide fine particles, antimony oxide fine particles, and indium oxide fine particles; Tin oxide complex oxide fine particles, tin oxide-antimony composite oxide fine particles, and indium oxide-tin composite oxide fine particles. Among them, the silica fine particles are preferably used since they have a low refractive index and high strength. The silica fine particles may have a hydroxyl group on the surface thereof. Examples of the organic fine particles include fine particles including a polystyrene type resin, an acrylic type resin, an organic silicone type resin, a polycarbonate type resin, and the like. Examples of the inorganic / organic mixed fine particles include silica fine particles having a functional group such as epoxy group, (meth) acryloyloxy group, and vinyl group on the surface. Silica fine particles having a reactive functional group such as hydroxyl group, epoxy group, (meth) acryloyloxy group and vinyl group on the surface are preferably used from the viewpoint of reacting with an active energy ray curable compound and crosslinking.

The particle size of the fine particles measured by the BET method or dynamic light scattering method (DLS method) is preferably 100 nm or less, more preferably 70 nm or less. If the particle size of the fine particles exceeds 100 nm, an optically transparent protective layer tends not to be obtained. Further, the particle size thereof is usually 3 nm or more.

The inorganic fine particles may be added as a solid fine particle in the curable resin composition, or may be added as a colloidal product dispersed in a solvent. As the solvent, an organic solvent is preferably used since drying can be performed relatively easily. The inorganic fine particles dispersed in the organic solvent preferably used in the present invention include colloidal silica. The concentration of silica in the colloidal silica is not particularly limited, and a commercially available product, for example, about 20 to 40% by weight can be used. The colloidal silica may be used alone or in combination of two or more.

Examples of the colloidal silica available as a commercially available product include "methanol silica sol" (silica particle diameter 10 to 15 nm, solid content 30% by weight, manufactured by Nissan Chemical Industries, Ltd.) in which the organic solvent is methyl alcohol, "MA- Quot; ST-M "(silica particle diameter 20 to 25 nm, solid content 40 weight%, manufactured by Nissan Chemical Industries, Ltd.)," OSCAL 1132 "(silica particle diameter 10 to 20 nm, To 31% by weight); OSCAL 1232 " (manufactured by Shokuba Kasei Kogyo Co., Ltd., silica particle diameter: 10 to 20 nm, solid content: 30 to 31 wt%), the organic solvent being ethyl alcohol; OSCAL 1332 " (trade name, manufactured by Shokuba Kasei Kogyo Co., Ltd., silica particle diameter: 10 to 20 nm, solid content: 30 to 31 wt%), which is an n-propyl alcohol; (Silica particle diameter 10 to 15 nm, solid content 30% by weight) manufactured by Nissan Chemical Industries, Ltd., and "OSCAL 1432" (manufactured by Shokubai Kasei Kogyo Co., Ltd., silica Particle diameter 10 to 20 nm, solid content 30 to 31% by weight); (Manufactured by Nissan Chemical Industries, Ltd., silica particle diameter 10 to 15 nm, solid content 20 wt%), "OSCAL 1532" (manufactured by Shokubai Kasei Kogyo Co., Ltd., Silica particle diameter 10 to 20 nm, solid content 30 to 31 wt%); "EG-ST" (manufactured by Nissan Chemical Industries, Ltd., silica particle diameter 10 to 15 nm, solid content 20 wt%) in which the organic solvent is ethylene glycol; "OSCAL 1632" (silica particle diameter 10 to 20 nm, solid content 30 to 31 wt%, manufactured by Shokuba Kasei Kogyo Co., Ltd.) in which the organic solvent is ethyl cellosolve; "NPC-ST" (manufactured by Nissan Chemical Industries, Ltd., silica particle diameter 10 to 15 nm, solid content 30% by weight) in which the organic solvent is ethylene glycol mono n-propyl ether; DMAC-ST-ZL "(manufactured by Nissan Chemical Industries, Ltd., silica particle diameter: 10 to 15 nm, solid content: 20 wt%) having an organic solvent of dimethylacetamide; Silica particle diameter 70 to 100 nm, solid content 20% by weight); "XBA-ST" (silica particle diameter 10 to 15 nm, solid content 30% by weight, manufactured by Nissan Chemical Industries, Ltd.) in which the organic solvent is a mixture of xylene and n-butyl alcohol; "MIBK-ST" (manufactured by Nissan Chemical Industries, Ltd., silica particle diameter 10 to 15 nm, solid content 30% by weight) having an organic solvent of methyl isobutyl ketone; SP-1120 "(manufactured by Nissan Chemical Industries, Ltd., silica particle diameter 10 to 15 nm, solid content 30% by weight)" MEK- Silica particle diameter: 15 to 20 nm; solid content: 5 to 10% by weight); "SP-6120" (silica particle diameter: 15 to 20 nm, solid content: 5 to 10% by weight; manufactured by Konishi Chemical Industry Co., Ltd.); "Snowtex 20" which is a dispersion medium, "Snowtex C" (manufactured by Nissan Chemical Industries, Ltd., silica particle diameter: 10 to 20 nm), silica particle diameter 10 to 20 nm) And one or more of these can be preferably used.

Examples of commercial products of solid fine silica particles include "AEROSIL 50", "AEROSIL 130" and other such "AEROSIL" series sold by Nippon Aerosil Co., Ltd., Nipsil E "series such as" Nipsil E 150K "and" Nipsil E 200 "sold by Nippon Silica Kogyo Co., Ltd., and the like can also be preferably used.

The fine particles are preferably added in an amount of 5 to 250 parts by weight, more preferably 10 to 100 parts by weight, per 100 parts by weight of the active energy ray curable compound contained in the curable resin composition. If the added amount of the fine particles is less than 5 parts by weight based on 100 parts by weight of the active energy ray curable compound, the hardness of the protective layer may not be sufficiently improved by the addition of the fine particles. On the other hand, if the added amount of the fine particles exceeds 250 parts by weight based on 100 parts by weight of the active energy ray curable compound, the adhesion between the polarizing film and the protective layer may be deteriorated. When the added amount of the fine particles exceeds 250 parts by weight, the dispersion stability of the fine particles in the curable resin composition may be lowered, or the viscosity of the curable resin composition may excessively increase.

The curable resin 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, and the mechanical strength of the protective layer and the adhesion of 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 and N-butyl acridone; Other examples include?,? - diethoxyacetophenone, benzyl, fluorenone, xanthone, uranyl compound, halogen compound and the like. Each of these may be used alone or in combination with at least one other. 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.

Further, the curable resin composition may contain an antistatic agent for imparting an antistatic property to the polarizing plate. The antistatic agent is not particularly limited, and known antistatic agents can be used. For example, cationic surfactants such as acyloylamidopropyldimethylhydroxyethylammonium nitrate, acyloylamidopropyltrimethylammonium sulfate and cetylmorphonium methosulfate; Anionic surfactants such as linear alkylphosphate potassium salt, polyoxyethylene alkylphosphate potassium salt, and alkanesulfonate; Nonionic surfactants such as N, N-bis (hydroxyethyl) -N-alkylamine, fatty acid ester derivatives thereof, polyhydric alcohol fatty acid partial esters and the like. The compounding ratio of these antistatic agents is appropriately determined in accordance with desired properties, but is usually about 0.1 to 20 parts by weight based on 100 parts by weight of the active energy ray curable compound.

To the curable resin composition, a known polymer additive usually used for a polymer material may be added. Examples thereof include primary antioxidants such as phenol type and amine type, secondary antioxidants of sulfur type, hindered amine type light stabilizers (HALS), benzophenone type, benzotriazole type, and benzoate type, and the like .

Further, the curable resin composition may contain a leveling agent as required. When the curable resin composition is applied to a polarizing film or a base material and the surface property of the cured product of the curable resin composition is poor when the polarizing film or the substrate has poor wettability to the base material, have. As the leveling agent, various compounds such as a silicone type, a fluorine type, a polyether type, an acrylic acid copolymer type, a titanate type and the like 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, 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 resin composition to be. When the amount of the leveling agent to be added is less than 0.01 part by weight based on 100 parts by weight of the active energy ray curable compound, improvement in wettability and surface properties may be insufficient. If the amount of the leveling agent added is more than 1 part by weight based on 100 parts by weight of the active energy ray curable compound, the adhesion between the polarizing film and the protective layer may be deteriorated.

Further, the curable resin composition may contain a solvent as required. The solvent is appropriately selected depending on the solubility of components constituting the curable resin 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; Cellosolves such as methyl acetate, ethyl acetate, and acetic acid; And halogenated hydrocarbons such as methylene chloride and chloroform. The compounding ratio of the solvent is suitably determined in view of the viscosity and the like of the desired active energy ray curable resin composition in consideration of processability such as film forming property.

As a method for forming the protective layer on one side or both sides of the polarizing film, for example, the following method can be mentioned. First, the curable resin 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 required, a base material having a coating film made of the curable resin composition is bonded to the polarizing film so that the coating film side becomes a bonding surface. In this case, when the protective layer is laminated on both surfaces of the polarizing film, two substrates having a coated film are prepared, and the two substrates are bonded to both surfaces of the polarizing film. Subsequently, the laminate is irradiated or heated with an active energy ray such as visible light, ultraviolet ray, X-ray or electron beam to cure the coating film composed of the curable resin composition to form a protective layer. Finally, the base material is peeled off to obtain a polarizing plate having a protective layer on one side or both sides of the polarizing film. The thickness of the protective layer is preferably as thin as possible in consideration of the thin and lightweight property. However, if the thickness of the protective layer is too thin, the polarizing film can not be sufficiently protected and the handling property is also insufficient. Therefore, the thickness of the protective layer is preferably about 1 to 35 mu m.

Although it is possible to form the protective layer directly on the polarizing film and cure it, when the curable resin composition contains a solvent and is cured after being subjected to a drying process, the polarizing film may be eroded or dried The above-mentioned method is preferable from the viewpoint of preventing shrinkage at a temperature. When the protective layer is formed on both surfaces of the polarizing film, the components contained in the curable resin composition for forming both protective layers may be the same or different.

When curing is carried out by irradiation of an active energy ray, the light source used is not particularly limited, but has a light emission distribution at a wavelength of 400 nm or less. Examples of such light sources include low pressure mercury lamps, medium pressure mercury lamps, high pressure mercury lamps, A lamp, a microwave excited mercury lamp, a metal halide lamp, or the like. The light irradiation intensity to the curable resin composition may vary depending on the above composition, but it is preferable that the irradiation intensity in the wavelength range effective for activation of the photo radical polymerization initiator and / or photo cation polymerization initiator is 10 to 2500 mW / cm 2. When the irradiation intensity to the curable resin composition is less than 10 mW / cm 2, the reaction time becomes excessively long. When the irradiation intensity exceeds 2500 mW / cm 2, heat radiated from the lamp and heat generated during polymerization of the curable resin composition, There is a possibility of causing deterioration of yellowing or polarizing film. The light irradiation time to the curable resin composition is controlled for each of the above compositions, and is not particularly limited, but is preferably set so that the integrated light amount expressed as a product of irradiation intensity and irradiation time is 10 to 2500 mJ / cm 2. When the amount of accumulated light in the curable resin composition is less than 10 mJ / cm 2, the generation of active species derived from the polymerization initiator is insufficient, and the curing of the obtained protective layer may be insufficient. If the accumulated light quantity exceeds 2500 mJ / cm 2, the irradiation time becomes extremely 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 the transmittance of the polarizing film are not deteriorated.

<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 plate, a light collecting plate, 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 plate is used for the purpose of compensating the retardation by the liquid crystal cell, and for example, a birefringent film including a stretched film of various plastics, a film on which a discotic liquid crystal or a nematic liquid crystal is aligned and fixed, And the above-mentioned liquid crystal layer is formed. In this case, a cellulose base film such as triacetyl cellulose 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, or a dot-laid sheet.

The brightness enhancement film is used for the purpose of improving brightness in a liquid crystal display or the like, and examples thereof include a reflection type polarized light separation sheet designed to laminate a plurality of thin film films having different anisotropy of refractive index from each other to generate anisotropy in reflectance, An orientation film of a liquid crystal polymer, and a circularly polarized light separation sheet on which the aligned liquid crystal layer is supported on a film base.

The optical functional layer may be used alone or in combination of two or more. The bonding of the optical functional layer to the protective layer may be performed by directly bonding the protective layer to the optical functional layer, or by using an adhesive or a pressure-sensitive adhesive. An adhesive or a pressure-sensitive adhesive may also be used for bonding the optical functional layers.

As a method of directly bonding the protective layer and the optical functional layer, an active energy ray curable resin composition is coated on one surface of the optical functional layer to form a coating film on the retarder, and then the retardation plate And a method in which the coating film is cured by bonding to a polarizing film and thereafter irradiating an active energy ray. By such a production method, a polarizing film, a protective layer, and a retardation plate can be directly bonded to each other without interposing another layer (for example, an adhesive layer or a pressure-sensitive adhesive layer).

The optical functional layer can be used as it is for the production of the optical member according to the present invention, but the bonding surface with the coating film forming the protective layer can also be subjected to the corona discharge treatment and the plasma treatment.

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.

<Examples>

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. In the examples, "part (s)" and "% " used in the amounts and 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 and a degree of saponification of 99.9 mol% or more and having a thickness of 75 탆 was immersed in pure water at 30 캜 and immersed in an aqueous solution of 0.02 / 2/100 by weight of iodine / potassium iodide / water at 30 캜 Respectively. Thereafter, 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 dried at 65 占 폚 to obtain a polarizing film (30 占 퐉 thick) in which iodine was adsorbed and oriented in 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 curable resin composition I)

The following components were mixed to obtain a curable resin composition I.

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

(3-ethyl-3-oxetanylmethyl) ether (Aronoxetane OXT-221, manufactured by Toagosei Co., Ltd.): 15 parts

Tricyclodecane dimethanol diacrylate (A-DCP, manufactured by Shin-Nakamura Chemical Co., Ltd.): 50 parts

2-hydroxy-2-methyl-1-phenylpropan-1-one (DAROCUR 1173: photoradical polymerization initiator, manufactured by Ciba Specialty Chemicals)

Photo-cationic polymerization initiator based on 4,4'-bis [diphenylsulfonio] diphenylsulfide bishexafluorophosphate (ADEKA OPTOMER SP-150, manufactured by Adeka Co., Ltd.): 2.5 parts

Silicone leveling agent (SH710, manufactured by Toray Dow Corning Co., Ltd.): 0.2 part

The A-DOG (diacrylate of hydroxypivalic aldehyde and acetyl compound of trimethylolpropane) is a compound having the following structure.

(Production Example 3: Production of curable resin composition II)

The following components were mixed to obtain a curable resin composition II.

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

(3-ethyl-3-oxetanylmethyl) ether (Aronoxetane OXT-221, manufactured by Toagosei Co., Ltd.): 15 parts

Diacrylate of an acetal compound of hydroxypivalic aldehyde and trimethylol propane (A-DOG, manufactured by Shin-Nakamura Chemical Co., Ltd.): 50 parts

2-hydroxy-2-methyl-1-phenylpropan-1-one (DAROCUR 1173: photoradical polymerization initiator, manufactured by Ciba Specialty Chemicals)

Photo-cationic polymerization initiator based on 4,4'-bis [diphenylsulfonio] diphenylsulfide bishexafluorophosphate (ADEKA OPTOMER SP-150, manufactured by Adeka Co., Ltd.): 2.5 parts

Silicone leveling agent (SH710, manufactured by Toray Dow Corning Co., Ltd.): 0.2 part

(Production Example 4: Production of curable resin composition III)

The following components were mixed to obtain a curable resin composition III.

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

(3-ethyl-3-oxetanylmethyl) ether (Aronoxetane OXT-221, manufactured by Toagosei Co., Ltd.): 15 parts

Triacrylate of 1,3,5-tris (2-hydroxyethyl) isocyanurate (A-9300, Shin Nakamura Chemical Industry Co., Ltd.): 50 parts

2-hydroxy-2-methyl-1-phenylpropan-1-one (DAROCUR 1173: photoradical polymerization initiator, manufactured by Ciba Specialty Chemicals)

Photo-cationic polymerization initiator based on 4,4'-bis [diphenylsulfonio] diphenylsulfide bishexafluorophosphate (ADEKA OPTOMER SP-150, manufactured by Adeka Co., Ltd.): 2.5 parts

Silicone leveling agent (SH710, manufactured by Toray Dow Corning Co., Ltd.): 0.2 part

(Production Example 5: Production of curable resin composition IV)

The following components were mixed to obtain a curable resin composition IV.

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

(3-ethyl-3-oxetanylmethyl) ether (Aronoxetane OXT-221, manufactured by Toagosei Co., Ltd.): 15 parts

Pentaerythritol tetraacrylate (A-TMMT, manufactured by Shin-Nakamura Chemical Co., Ltd.): 50 parts

2-hydroxy-2-methyl-1-phenylpropan-1-one (DAROCUR 1173: photoradical polymerization initiator, manufactured by Ciba Specialty Chemicals)

Photo-cationic polymerization initiator based on 4,4'-bis [diphenylsulfonio] diphenylsulfide bishexafluorophosphate (ADEKA OPTOMER SP-150, manufactured by Adeka Co., Ltd.): 2.5 parts

Silicone leveling agent (SH710, manufactured by Toray Dow Corning Co., Ltd.): 0.2 part

(Production Example 6: production of curable resin composition V)

73 parts of the curable resin composition I and 30 parts (in terms of solid content) of colloidal silica (MEK-ST, silica particle diameter 10 to 15 nm, manufactured by Nissan Chemical Industries, Ltd.) were mixed to obtain a curable resin composition V.

(Production Example 7: Production of curable resin composition VI)

73 parts of the curable resin composition II and 30 parts (in terms of solid content) of colloidal silica (MEK-ST, silica particle diameter 10 to 15 nm, manufactured by Nissan Chemical Industries, Ltd.) were mixed to obtain a curable resin composition VI.

(Production Example 8: Production of curable resin composition VII)

The following components were mixed to obtain a curable resin composition VII.

3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (Celloxide 2021P, manufactured by Daicel Chemical Industries, Ltd.): 15 parts

3 parts of 3-ethyl-3-hydroxymethyloxetane (AARON oxetane OXT-101, manufactured by Toagosei Co., Ltd.): 15 parts

Ethylene oxide-modified diacrylate of bisphenol A (Aronix M-210, manufactured by Toagosei Co., Ltd.): 49 parts

Trimethylolpropane triacrylate (TMPTA, manufactured by Shin-Nakamura Chemical Co., Ltd.): 21 parts

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

Photocatalyst polymerization initiator based on 4,4'-bis [diphenylsulfonio] diphenyl sulfide bishexafluorophosphate (ADEKA OPTOMER SP-150, manufactured by ADEKA CO., LTD.): 2 parts

Silicone leveling agent (SH710, manufactured by Toray Dow Corning Co., Ltd.): 0.2 part

(Production Example 9: Production of curable resin composition VIII)

The following components were mixed to obtain a curable resin composition VIII.

Diglycidyl ether of nucleus hydrogenated bisphenol A (Epikote YX8000, manufactured by Japan Epoxy Resin Co., Ltd.): 100 parts

40 parts of photo cationic polymerization initiator based on 4,4'-bis [diphenylsulfonio] diphenyl sulfide bishexafluorophosphate (Adeka Optomer SP-150, manufactured by Adeka Co., Ltd.)

Silicone leveling agent (SH710, manufactured by Toray Dow Corning Co., Ltd.): 0.2 part

(Production Example 10: preparation of curable resin composition IX)

The following components were mixed to obtain a curable resin composition IX.

Diglycidyl ether of nucleus hydrogenated bisphenol A (Epikote YX8000, manufactured by Japan Epoxy Resin Co., Ltd.): 70 parts

(Aroon Oxetane OXT-121, manufactured by Toagosei Co., Ltd.): 30 parts (1 part) of 1,4-bis [{(3-ethyl-3-oxetanyl) methoxy}

40 parts of photo cationic polymerization initiator based on 4,4'-bis [diphenylsulfonio] diphenyl sulfide bishexafluorophosphate (Adeka Optomer SP-150, manufactured by Adeka Co., Ltd.)

Silicone leveling agent (SH710, manufactured by Toray Dow Corning Co., Ltd.): 0.2 part

(Production Example 11: Production of curable resin composition X)

The following components were mixed to obtain a curable resin composition X.

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

(3-ethyl-3-oxetanylmethyl) ether (Aronoxetane OXT-221, manufactured by Toagosei Co., Ltd.): 15 parts

· 50 parts of 2-hydroxy-3-phenoxypropyl acrylate (Shin-Nakamura Chemical Industries, Ltd., 702A)

2-hydroxy-2-methyl-1-phenylpropan-1-one (DAROCUR 1173: photoradical polymerization initiator, manufactured by Ciba Specialty Chemicals)

Photo-cationic polymerization initiator based on 4,4'-bis [diphenylsulfonio] diphenylsulfide bishexafluorophosphate (ADEKA OPTOMER SP-150, manufactured by Adeka Co., Ltd.): 2.5 parts

Silicone leveling agent (SH710, manufactured by Toray Dow Corning Co., Ltd.): 0.2 part

&Lt; Example 1 >

The curable resin composition I obtained in Production Example 2 was coated on a polyethylene terephthalate (PET) film (Ester Film E7002, manufactured by Toyobo Co., Ltd.) using a bar coater. Subsequently, two PET films coated with a curable resin composition were adhered to both sides of the polarizing film obtained in Production Example 1 using a bonding device (LPA3301 manufactured by Fuji Plastics Co., Ltd.) such that the coating film side was a bonding surface . Subsequently, the layered product was irradiated with ultraviolet rays at a cumulative light quantity of 1500 mJ / cm &lt; 2 &gt; by a D valve manufactured by Fusion UV System Co., and the coating films on both sides were cured. Finally, the PET film on both sides was peeled off to obtain a polarizing plate having a protective layer on both surfaces of the polarizing film.

&Lt; Examples 2 to 6 and Comparative Examples 1 to 4 >

A polarizing plate was produced in the same manner as in Example 1 except that the curable resin composition shown in Table 1 described below was used in place of the curable resin composition I, respectively.

&Lt; Example 7 >

The curable resin composition V obtained in Production Example 6 was coated on a polyethylene terephthalate (PET) film (Ester Film E7002, manufactured by Toyobo Co., Ltd.) using a bar coater. Subsequently, the resultant was dried at 80 DEG C for 3 minutes to remove the solvent. Subsequently, two PET films coated with a curable resin composition were adhered to both sides of the polarizing film obtained in Production Example 1 using a bonding device (LPA3301 manufactured by Fuji Plastics Co., Ltd.) such that the coating film side was a bonding surface . Subsequently, the layered product was irradiated with ultraviolet rays at a cumulative light quantity of 1500 mJ / cm &lt; 2 &gt; by a D valve manufactured by Fusion UV System Co., and the coating films on both sides were cured. Finally, the PET film on both sides was peeled off to obtain a polarizing plate having a protective layer on both surfaces of the polarizing film.

&Lt; Example 8 >

The curable resin composition VI obtained in Production Example 7 was coated on a polyethylene terephthalate (PET) film (Ester Film E7002, manufactured by Toyobo Co., Ltd.) using a bar coater. Subsequently, the resultant was dried at 80 DEG C for 3 minutes to remove the solvent. Subsequently, two PET films coated with a curable resin composition were adhered to both sides of the polarizing film obtained in Production Example 1 using a bonding device (LPA3301 manufactured by Fuji Plastics Co., Ltd.) such that the coating film side was a bonding surface . Subsequently, the layered product was irradiated with ultraviolet rays at a cumulative light quantity of 1500 mJ / cm &lt; 2 &gt; by a D valve manufactured by Fusion UV System Co., and the coating films on both sides were cured. Finally, the PET film on both sides was peeled off to obtain a polarizing plate having a protective layer on both surfaces of the polarizing film.

&Lt; Comparative Example 5 &

(TRW842A, Sumitomo 3M Co., Ltd.) having a protective film made of triacetylcellulose having a thickness of 80 占 퐉 (abbreviated as "TAC" in Table 1) bonded to both surfaces of a polarizing film on which iodine was adsorbed and oriented on a polyvinyl alcohol film Ltd.) was used as Comparative Example 5.

Table 1 shows the compositions of the compositions used in Examples 1 to 8 and Comparative Examples 1 to 5, the modulus of elasticity of the composition, the modulus of elasticity of the cured product composed of only the (meth) acrylic compound and the radical polymerization initiator Quot; acrylic "in the column of" elastic modulus ") and the storage elastic modulus at 80 DEG C of the cured product of each composition. The elastic modulus and the storage elastic modulus were obtained as follows.

[Measurement method of elastic modulus]

A curable resin composition for forming a protective layer was formed on one side of a polyethylene terephthalate (PET) film (Ester Film E7002, manufactured by Toyobo Co., Ltd.) using a coating machine (Barcoater, , And ultraviolet rays were irradiated with a total dose of 1,500 mJ / cm 2 by a D valve manufactured by Fusion UV System to cure the curable resin composition. Subsequently, the cured product was cut into a length of 1 cm width x 8 cm for each PET film, and the PET film was peeled to obtain a sample. Subsequently, the long side portion of the sample was sandwiched between upper and lower grippers of AUTOGRAPH AG-1S manufactured by Shimadzu Corporation under the conditions of 23 ° C and 55% RH so that the gap between grippers was 5 cm. (Manufactured by Shimadzu Seisakusho Co., Ltd.) from the initial straight line of the obtained stress-strain curve at a tensile rate of 10 mm / min under an environment of relative humidity of 55% , TRAPEZIUM2) was used to calculate the elastic modulus. Also, a cured product comprising only the (meth) acrylic compound and the radical polymerization initiator used in each of the curable resin compositions was prepared and measured in the same manner.

[Method of measuring elastic modulus at 80 占 폚]

Each of the curable resin compositions was coated on a PET film in the same manner as described above, and irradiated with ultraviolet rays to be cured. Subsequently, it was cut into 5 mm 30 mm and the PET film was peeled to obtain a single cured film of each curable resin composition. The obtained single film was gripped in such a direction as to stretch its long side and set at a gap of 2 cm at the gripper, a frequency of 1 Hz, and a temperature raising rate of 3 DEG C / min, using DVA-220 manufactured by Haitai Seisakusho KK , And the storage elastic modulus at 80 캜 was obtained.

In Table 1, the epoxy-based cationic polymerizable compound, the oxetane-based cationic polymerizable compound, the radically polymerizable compound, the cationic polymerization initiator, and the radical-based polymerization initiator were respectively added to the left side As shown in Fig. In some cases, the symbols are the same as the product names and the abbreviations. All the symbols shown in Table 1 are shown below.

[Epoxy-based cationic polymerizable compound]

CEL 2021P: Celloxide 2021P manufactured by Daicel Chemical Industries, Ltd., and the chemical name is 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate.

YX8000: Epikote YX8000 manufactured by Japan Epoxy Resin Co., Ltd., the chemical name is diglycidyl ether of hydrogenated bisphenol A.

[Oxetane-based cationic polymerizable compound]

OXT-221: Aronoxetane OXT-221 manufactured by Toagosei Co., Ltd., and the chemical name is bis (3-ethyl-3-oxetanylmethyl) ether.

OXT-101: Aronoxetane OXT-101 manufactured by Toagosei Co., Ltd., and 3-ethyl-3-hydroxymethyloxetane (chemical name).

OXT-121: Aronoxetane OXT-121 manufactured by Toagosei Co., Ltd., and the chemical name is 1,4-bis [{(3-ethyl-3-oxetanyl) methoxy} methyl] benzene.

[Radical Polymerizable Compound]

A-DCP: A-DCP manufactured by Shin Nakamura Chemical Industry Co., Ltd., and tricyclodecane dimethanol diacrylate (trade name).

A-DOG: A-DOG manufactured by Shin Nakamura Chemical Industry Co., Ltd .; chemical name is diacrylate of an acetal compound of hydroxypivaldehyde and trimethylolpropane [in the formula 2, Q ₁ = acryloyloxymethyl group , Q ₂ = 2-acryloyloxy-1,1-dimethylethyl group, and R = ethyl group].

A-9300: A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd., and triacrylate of 1,3,5-tris (2-hydroxyethyl) isocyanurate.

A-TMMT: A-TMMT manufactured by Shin Nakamura Chemical Industry Co., Ltd., and pentaerythritol tetraacrylate (trade name).

M-210: Aronix M-210, manufactured by Toagosei Co., Ltd., the chemical name is ethylene oxide-modified diacrylate of bisphenol A.

TMPTA: The chemical name is trimethylolpropane triacrylate.

702A: 702A, manufactured by Shin-Nakamura Chemical Co., Ltd., and 2-hydroxy-3-phenoxypropyl acrylate (trade name).

&Lt; Evaluation test >

The following evaluation tests were carried out on the polarizing plates produced in Examples 1 to 8 and Comparative Examples 1 to 5. The results are shown in Table 2 below.

[1] Adhesion test (Crosshatch test)

A test was performed in which one side of the protective layer side of the polarizing plate was bonded to the glass via a pressure-sensitive adhesive, and a checkerboard scale of 1 mm side was cut with a cutter knife on the surface of the protective layer opposite to the glass side, And the adhesiveness was evaluated by the number of grid scales remaining without being peeled out of the 100 grid squares. A represents the case where the number of grid squares remaining is 95 to 100/100, B represents the case where the number of grid marks is 50 to 95/100, and C represents the case of 0 to 49/100.

[2] Water temperature test

Each polarizing plate was subjected to the following water temperature resistance test (hot water immersion test) to evaluate the water resistance. First, the polarizing plate was cut into a rectangle of 5 cm x 2 cm with the absorption axis (stretching direction) of the polarizing plate as the long side, to prepare a sample, and the dimension in the long side direction was measured accurately. At this time, the sample uniformly exhibits a unique color over the entire surface due to the iodine adsorbed on the polyvinyl alcohol film. Fig. 1 is a diagram schematically showing an evaluation test method for water resistance. Fig. 1 (A) shows sample 1 before immersion in hot water, and Fig. 1 (B) shows sample 1 after immersion in hot water. As shown in Fig. 1 (A), one short side of the sample was held by the grip portion 5, and about 80% of the sample in the longitudinal direction was immersed in a water bath at 60 deg. C and held for 4 hours. Thereafter, the sample (1) was taken out from the water tank and the water was wiped off.

By the immersion in hot water, the polarizing film 4 constituting the polarizing plate shrinks. That is, as shown in Fig. 1 (B), the polarizing film 4 positioned in the center of the polarizing plate shrinks by hot water immersion, so that the region 2 in which the polarizing film 4 is not present between the protective films is formed do. The distance from the end 1a of the sample 1 (the end of the protective film) to the end of the polarizing film 4 contracted at the center of the short side was defined as the contraction length. Further, iodine is eluted from the periphery of the polarizing film 4 in contact with the hot water due to the hot water immersion, and a portion 3 in which the color is missing at the periphery of the sample 1 is generated. The length of the part without the color was defined as the length without iodine. The sum of the length of shrinkage and the length of missing iodine was defined as total erosion length X. [ That is, the total erosion length X is the distance from the end 1a of the sample 1 (the end of the protective film) at the center of the short side of the sample 1 to the region where the color unique to the polarizer remains. It can be judged that the smaller the total erosion length X, the higher the adhesiveness (water resistance) in the presence of water. A was evaluated as A when the erosion distance was less than 1000 탆, B was evaluated when the erosion distance was less than 3000 탆 and C was evaluated as 3000 탆 or more.

[3] Dimensional stability test

Each polarizing plate was measured for dimensional change after being placed in a drying environment of 85 캜 for 120 hours. That is, first, the polarizing plate was cut into a size of 8 cm x 8 cm, and bonded to the glass through a pressure-sensitive adhesive to obtain a measurement sample. 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 left for 24 hours under an environment of a temperature of 23 캜 and a relative humidity of 55%. Dimensions in the longitudinal direction (MD) and the transverse direction (TD) were measured with a two-dimensional measuring machine (NEXIV VMR-12072, manufactured by Nikon Corporation) ), And the rate of dimensional change was calculated from the following equation.

Table 2 shows the rate of dimensional change in the MD direction (meaning that all shrinkage is minus sign). A, B, and C were evaluated as A, B, and C, respectively, when the dimensional change rate was less than 0.7%, 0.7%, and 1.0%, respectively.

[4] Optical durability test

Each polarizing plate was allowed to stand at 85 DEG C or 90 DEG C relative humidity at 60 DEG C, and the change in optical performance over time was determined. That is, first, the polarizing plate was cut into a size of 3 cm x 3 cm, and bonded to the glass through a pressure-sensitive adhesive to obtain a measurement sample. 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 left for 24 hours under an environment of a temperature of 23 캜 and a relative humidity of 55%. For this sample, an optional accessory "film holder with a polarizing film" was set on an ultraviolet visible spectrophotometer (UV2450, manufactured by Shimadzu Corporation) to transmit the polarizing plate in a wavelength range of 380 to 700 nm (Unit:%) and the unitary transmittance Ty (unit:%) are determined based on the measured transmittance spectra in the axial direction and the absorption axis direction, and further the group b ^* (No unit) was obtained. The optical performance in this state was initially measured and the optical performance after standing at 85 캜 for 120 hours under an environment of 90% relative humidity at 60 캜 was measured and the polarization degree change ΔPy, The color change? B ^* was calculated.

ΔPy = Py after test - Initial Py

ΔTy = Ty after test - Initial Ty

Δb ^* = b ^* after the test - initial b ^*

For ΔPy, the case where the amount of change in the degree of polarization represented by% is less than 1 point is evaluated as A, the case where B is less than 5 points and B is 5 points or more is evaluated as C. As to? Ty, A was evaluated as A when the variation of the transmittance in% was less than 3 points, B was evaluated in the case of 3 points or more and less than 5 points, and C in 5 points or more. With respect to? B ^* , the case where the amount of change was less than 3 was evaluated as A, the case where the amount of variation was 3 or more but less than 5 was evaluated as B, and the case of 5 or more was evaluated as C. Table 2 shows the evaluation results of? Py and? B ^* when placed at 85 占 폚 in dry state and the evaluation results of? Py and? Ty when the sample is placed in an environment at 60 占 폚 and a relative humidity of 90%.

[4] Measurement of film thickness

The film thickness of the entire polarizing plate (laminate of upper and lower protective films and polarizing films) was measured using a film thickness meter (ZC-101, manufactured by Nikon Corporation).

It can be seen from Table 2 that a polarizing plate of a thin film excellent in water resistance, dimensional stability, and optical durability is obtained with a protective film excellent in adhesion to a polarizing film in Examples.

It should be understood that the disclosed embodiments and examples are illustrative in all respects and not as 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 (14)

A polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol based resin film and a protective layer comprising a cured product of a curable resin composition containing an active energy ray curable compound formed on at least one side of the polarizing film,
Wherein the active energy ray-curable compound contains a compound having at least one epoxy group in the molecule and a (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule,
The elastic modulus of the protective layer is 3300 to 10000 MPa,
Wherein the (meth) acrylic compound is such that a cured product comprising only the (meth) acrylic compound and the polymerization initiator provides an elastic modulus of 3000 MPa or more. A polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol based resin film and a protective layer comprising a cured product of a curable resin composition containing an active energy ray curable compound formed on at least one side of the polarizing film,
Wherein the active energy ray-curable compound contains a compound having at least one epoxy group in the molecule and a (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule,
The elastic modulus of the protective layer is 3300 to 10000 MPa,
Wherein the curable resin composition further contains fine particles. The polarizing plate according to any one of claims 1 to 5, wherein the active energy ray-curable compound contains the (meth) acrylic compound in an amount of 10 to 70 parts by weight in 100 parts by weight. 3. The polarizing plate according to claim 2, wherein the (meth) acrylic compound provides a cured product comprising only the (meth) acrylic compound and the polymerization initiator with an elastic modulus of 3000 MPa or more. The polarizing plate according to any one of claims 1 to 3, wherein from 100 parts by weight of the active energy ray-curable compound, 30 to 90 parts by weight of a compound having at least one epoxy group in the molecule is contained. The polarizing plate according to claim 1 or 2, wherein the compound has at least one epoxy group in which the compound having at least one epoxy group in the molecule is bonded to the alicyclic ring. The polarizing plate according to claim 1 or 2, wherein the curable resin composition further contains an oxetane-based compound. The polarizing plate according to claim 2 or 4, wherein the curable resin composition contains 5 to 250 parts by weight of fine particles per 100 parts by weight of the active energy ray curable compound. The polarizing plate according to claim 2 or 4, wherein the fine particles are silica particles having a particle diameter of 100 nm or less. The polarizing plate according to claim 9, wherein the fine silica particles have at least one functional group selected from the group consisting of a hydroxyl group, an epoxy group, a (meth) acryloyloxy group and a vinyl group on the surface thereof. The polarizing plate according to claim 1 or 2, wherein the thickness of the protective layer is 1 to 35 탆. An optical member comprising the laminate of the polarizing plate and the optical functional layer according to claim 1 or 2. The optical member according to claim 12, wherein the optical function layer is any one of a retardation layer, a brightness enhancement film, and a surface treatment layer. A liquid crystal display device comprising the liquid crystal cell according to claim 1 or 2, or an optical member including a laminate of the polarizing plate and the optical function layer is disposed on one side or both sides of the liquid crystal cell.