JP2009216874A - Polarizing plate and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizing plate exhibiting high thinning and lightening-in-weight property and durability while maintaining high adhesiveness between a polarizing film and a protective layer and between the protective layer and a phase difference plate; and to provide a liquid crystal display using the polarizing plate. <P>SOLUTION: The polarizing plate is formed by stacking the polarizing film, a first protective layer, and the phase difference plate in this order, and the liquid crystal display uses the polarizing plate. The first protective layer is made of a curing object of active energy ray curing resin composition containing epoxy-based compound having two or more epoxy groups in a molecule and (meta) acrylic-based compound having one or more (meta) acryloyloxy groups in a molecule. The polarizing plate may further have a second protective layer stacked on the surface on the opposite side to the stacked side of the first protective layer in the polarizing film. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polarizing plate used for a liquid crystal display device and the like, and more particularly to a polarizing plate in which a protective layer and a retardation plate are laminated on a polarizing film. The present invention also relates to 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, the polarizing plate has a configuration in which a protective layer made of a transparent resin film is laminated on one or both sides of a polarizing film using an aqueous adhesive or the like. As such a transparent resin film, a triacetyl cellulose film (TAC film) is often used because of its excellent optical transparency and moisture permeability. The polarizing plate is bonded to the liquid crystal cell with an adhesive via another optical function layer as necessary, and is incorporated into the liquid crystal display device.

  In recent years, with the development of liquid crystal display devices in mobile devices such as notebook personal computers, mobile phones, car navigation systems, etc., the polarizing plates that make up liquid crystal display devices are thinner and lighter and have higher durability (high mechanical strength). Is now required. In addition, liquid crystal display devices for mobile use are required to be usable under wet heat, and polarizing plates used therefor are also required to have high heat and humidity resistance. In particular, when exposed to a high temperature and high humidity for a long period of time, there was a problem that the polarizing performance deteriorated or the polarizing film contracted. Therefore, the protective layer laminated on the polarizing film is required to improve the mechanical strength and the ability to suppress the contraction of the polarizing film (shrinkage suppressing force) as well as reducing the thickness and weight. .

  However, in the polarizing plate bonded with a TAC film as a protective layer, it is difficult to make the thickness of the protective layer 20 μm or less from the viewpoints of handleability and durability at the time of work, and there is a limit to reducing the thickness and weight. .

  As a technique that can solve the above problem, for example, Patent Document 1 discloses a technique in which a transparent thin film layer is formed by applying a resin solution to one or both sides of a polarizing film made of a hydrophilic polymer. Patent Document 2 discloses that a protective film is formed on a polarizer by curing an energy ray-curable composition containing an energy ray-polymerizable compound having a dicyclopentanyl residue or a dicyclopentenyl residue. A forming technique is disclosed. Patent Document 3 discloses a polarizing plate having a protective film mainly composed of an epoxy resin on at least one surface of a polarizer. Patent Document 4 discloses that at least one surface of a polarizer is protected with a cured product of an active energy ray-curable resin composition.

However, in the polarizing plates disclosed in Patent Documents 1 to 4, it is possible to reduce the thickness and weight of the polarizing plate, but the adhesion between the protective layer and the polarizing film and the optical layer laminated on the protective layer. There has been a problem that the adhesion to the functional layer (for example, a retardation plate) is not sufficient, or the mechanical strength and durability of the protective layer are not sufficient.
JP 2000-199819 A JP 2003-185842 A JP 2004-245924 A JP 2005-92112 A

  An object of the present invention is to provide a polarizing plate that is excellent in thin and lightweight properties and durability while maintaining good adhesion between the polarizing film and the protective layer and between the protective layer and the retardation plate. . Another object of the present invention is to provide a liquid crystal display device using such a polarizing plate and having excellent reliability.

  In the present invention, a polarizing film, a first protective layer, and a retardation plate are laminated in this order, and the first protective layer includes an epoxy compound having two or more epoxy groups in the molecule and an intramolecular molecule. A polarizing plate comprising a cured product of an active energy ray-curable resin composition containing a (meth) acrylic compound having one or more (meth) acryloyloxy groups is provided.

  The polarizing plate of the present invention preferably further comprises a second protective layer laminated on the surface of the polarizing film opposite to the side on which the first protective layer is laminated, and in this case, the second protective layer The protective layer is an active energy ray-curable resin composition comprising an epoxy compound having two or more epoxy groups in the molecule and a (meth) acryl compound having one or more (meth) acryloyloxy groups in the molecule. The cured product.

  The active energy ray-curable resin composition may further include an oxetane compound.

  The polarizing plate of the present invention may further have an optical functional layer laminated on the second protective layer. Examples of the optical functional layer include a brightness enhancement film and a surface treatment layer.

  Moreover, the polarizing plate of this invention may have further the adhesive layer laminated | stacked on the phase difference plate. In the present invention, as the polarizing film, a polyvinyl alcohol resin film having a dichroic dye adsorbed and oriented can be preferably used.

  Moreover, this invention provides the liquid crystal display device by which the polarizing plate of this invention is arrange | positioned at the single side | surface or both surfaces 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 reduced in thickness and weight, and between the polarizing film and the protective layer and between the protective layer and the protective layer. The adhesion between the liquid crystal and the phase difference plate is also good. Further, since the durability performance of the protective layer is improved, it is possible to provide a polarizing plate and a highly reliable liquid crystal display device that can sufficiently withstand heat treatment during device assembly and environmental conditions during device use. Such a polarizing plate of the present invention can be suitably applied to, for example, a liquid crystal display device for mobile use.

  The polarizing plate of the present invention is formed by laminating a polarizing film, a first protective layer, and a retardation plate in this order. A second protective layer may be laminated on the surface of the polarizing film opposite to the side on which the first protective layer is laminated. In the present invention, the first protective layer and the second protective layer have an epoxy compound having two or more epoxy groups in the molecule and one or more (meth) acryloyloxy groups in the molecule (meta ) It is formed by curing an active energy ray-curable resin composition containing an acrylic compound. Hereinafter, the polarizing plate of the present invention will be described in detail.

(Polarizing film)
In the present invention, the polarizing film is not particularly limited, but is preferably a film made of a polyvinyl alcohol-based resin, more specifically, a film in which a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol-based resin film. Can be used.

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

  A film obtained by forming such a polyvinyl alcohol resin is used as a raw film of a polarizing film. The method for forming a polyvinyl alcohol-based resin is not particularly limited, and can be formed by a known method. Although the film thickness of a polyvinyl alcohol-type raw film is not specifically limited, For example, it is about 10 micrometers-150 micrometers.

  A polarizing film is usually a process of uniaxially stretching a raw film made of a polyvinyl alcohol resin as described above, a process of dyeing a polyvinyl alcohol resin film with a dichroic dye and adsorbing the dichroic dye, two colors It is manufactured through a step of treating a polyvinyl alcohol-based resin film adsorbed with a functional dye with an aqueous boric acid solution and a step of washing with water after the treatment with an aqueous boric acid solution.

  Uniaxial stretching may be performed before dyeing with the dichroic dye, may be performed simultaneously with the dyeing, or may be performed after the dyeing. When uniaxial stretching is performed after dyeing with a dichroic dye, the uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Moreover, it is also possible to perform uniaxial stretching in these several steps. In uniaxial stretching, it may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using a hot roll. Further, it may be dry stretching such as stretching in the air, or may be wet stretching in which stretching is performed in a state swollen with a solvent. The draw ratio is usually about 4 to 8 times.

  In order to dye the polyvinyl alcohol resin film with the dichroic dye, for example, the polyvinyl alcohol resin film may be immersed in an aqueous solution containing the dichroic dye. As the dichroic dye, iodine, a dichroic dye or the like is used. In addition, it is preferable that the polyvinyl alcohol-type resin film performs the immersion process to water before a dyeing process.

  When iodine is used as the dichroic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide is usually employed as a dyeing method. The content of iodine in this aqueous solution is usually about 0.01 to 0.5 parts by weight with respect to 100 parts by weight of water, and the content of potassium iodide is usually 0.00 with respect to 100 parts by weight of water. About 5 to 10 parts by weight. The temperature of the aqueous solution used for dyeing is usually about 20 to 40 ° C., 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 immersing a polyvinyl alcohol-based resin film in a dye aqueous solution containing a water-soluble dichroic dye is usually employed as a dyeing method. The content of the dichroic dye in this dye aqueous solution is usually about 1 × 10 ⁻³ to 1 × 10 ⁻² parts by weight with respect to 100 parts by weight of water. The dye aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing assistant. The temperature of the aqueous dye solution is usually about 20 to 80 ° C., and the immersion time (dyeing time) in the aqueous dye solution is usually about 30 to 300 seconds.

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

  The polyvinyl alcohol resin film after the boric acid treatment is usually washed with water. The water washing treatment is performed, 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 ° C., and the immersion time is about 2 to 120 seconds. After washing with water, a drying process is performed to obtain a polarizing film. The drying treatment can be performed using a hot air dryer or a far infrared heater. A drying temperature is about 40-100 degreeC normally. 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 resin film can be produced. The thickness of the polarizing film can be about 5 to 40 μm.

(Protective layer)
In the present invention, on one surface of the polarizing film, an epoxy compound having two or more epoxy groups in the molecule (hereinafter sometimes simply referred to as an epoxy compound) and one or more (meth) in the molecule. A first protective layer made of a cured product of an active energy ray-curable resin composition containing a (meth) acrylic compound having an acryloyloxy group is laminated, and a retardation plate is further laminated on the first protective layer. To obtain a polarizing plate. Similarly, an epoxy compound having two or more epoxy groups in the molecule and one or more (meth) acryloyl in the molecule on the surface of the polarizing film opposite to the side on which the first protective layer is laminated. You may provide the 2nd protective layer which consists of hardened | cured material of the active energy ray-curable resin composition containing the (meth) acrylic-type compound which has an oxy group. By including an epoxy compound in the active energy ray-curable resin composition, it exhibits good adhesion to a polarizing film and a retardation film, as well as transparency, mechanical strength, thermal stability, moisture barrier properties, etc. A protective layer having excellent durability and high durability can be obtained. Here, in the present invention, the “epoxy compound having two or more epoxy groups in a molecule” has two or more epoxy groups in the molecule, and an active energy ray (for example, ultraviolet rays, visible light, It means a compound that can be cured by irradiation with an electron beam, X-ray or the like. Moreover, an epoxy-type compound, a (meth) acrylic-type compound, and the oxetane-type compound mentioned later may be generally called an active energy ray hardening compound.

  Although it does not restrict | limit especially as said epoxy-type compound, It is preferable to use the epoxy-type compound which does not contain an aromatic ring in a molecule | numerator as a main component from viewpoints, such as a weather resistance, a refractive index, and cationic polymerizability. Examples of such epoxy compounds that do not contain an aromatic ring in the molecule include hydrogenated epoxy compounds, alicyclic epoxy compounds, and aliphatic epoxy compounds.

  The hydrogenated epoxy compound can be obtained by selectively hydrogenating an aromatic epoxy compound in the presence of a catalyst under pressure. Examples of aromatic epoxy compounds include bisphenol-type epoxy resins such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and diglycidyl ether of bisphenol S; phenol novolac epoxy resins, cresol novolac epoxy resins, hydroxy Examples include novolak-type epoxy resins such as benzaldehyde phenol novolac epoxy resins; glycidyl ethers of tetrahydroxyphenylmethane, glycidyl ethers of tetrahydroxybenzophenone, and polyfunctional epoxy resins such as epoxidized polyvinylphenol. Of these, hydrogenated bisphenol A glycidyl ether is preferably used as the hydrogenated epoxy compound.

  The alicyclic epoxy compound means an epoxy compound having one or more epoxy groups bonded to the alicyclic ring. The “epoxy group bonded to the alicyclic ring” has a structure represented by the following formula. In formula, m is an integer of 2-5.

Accordingly, the alicyclic epoxy compound is a compound having at least one structure represented by the above formula and having a total of two or more epoxy groups in the molecule. More specifically, a compound in which one or a plurality of hydrogen groups in (CH ₂ ) _m in the above formula are bonded to another chemical structure can be an alicyclic epoxy compound. One or more hydrogen atoms in (CH ₂ ) _m may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group. Among alicyclic epoxy compounds, an epoxy compound having an oxabicyclohexane ring (m = 3 in the above formula) or an oxabicycloheptane ring (m = 4 in the above formula) is a cured product. It is more preferably used because of its high elastic modulus and excellent adhesion to a polarizing film. Although the structure of the alicyclic epoxy compound preferably used in the present invention is specifically exemplified below, it is not limited to these compounds.

  (A) Epoxycyclohexylmethyl epoxycyclohexanecarboxylates represented by the following formula (I):

(In the formula, R ¹ and R ² each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.)
(B) Epoxycyclohexanecarboxylates of alkanediol represented by the following formula (II):

(In the formula, R ³ and R ⁴ each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and n represents an integer of 2 to 20).
(C) Epoxycyclohexylmethyl esters of dicarboxylic acid represented by the following formula (III):

(In the formula, R ⁵ and R ⁶ each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and p represents an integer of 2 to 20).
(D) Epoxycyclohexyl methyl ethers of polyethylene glycol represented by the following formula (IV):

(In the formula, R ⁷ and R ⁸ independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and q represents an integer of 2 to 10).
(E) Epoxycyclohexyl methyl ethers of alkanediols represented by the following formula (V):

(In the formula, R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and r represents an integer of 2 to 20).
(F) Diepoxy trispiro compound represented by the following formula (VI):

(In the formula, R ¹¹ and R ¹² each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.)
(G) Diepoxy monospiro compound represented by the following formula (VII):

(In the formula, R ¹³ and R ¹⁴ each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.)
(H) Vinylcyclohexene diepoxides represented by the following formula (VIII):

(In the formula, R ¹⁵ represents a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.)
(I) Epoxycyclopentyl ethers represented by the following formula (IX):

(In the formula, R ¹⁶ and R ¹⁷ each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.)
(J) Diepoxytricyclodecanes represented by the following formula (X):

(In the formula, R ¹⁸ represents a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.)
Among the alicyclic epoxy compounds exemplified above, the following alicyclic epoxy compounds are commercially available or similar, and are preferably used because they are relatively easy to obtain. It is done.

(A) Esterified product of 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and (7-oxa-bicyclo [4.1.0] hept-3-yl) methanol [formula (I) In which R ¹ = R ² = H]
(B) 4-methyl-7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and (4-methyl-7-oxa-bicyclo [4.1.0] hept-3-yl) methanol Ester compounds of [In the formula (I), R ¹ = 4-CH ₃ , R ² = 4-CH ₃ compound],
(C) Esterified product of 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid and 1,2-ethanediol [in the formula (II), R ³ = R ⁴ = H, n = 2 Compound〕,
(D) (7-oxabicyclo [4.1.0] hept-3-yl) esterified product of methanol and adipic acid [compound of formula (III), wherein R ⁵ = R ⁶ = H, p = 4] ,
(E) (4-Methyl-7-oxabicyclo [4.1.0] hept-3-yl) esterified product of methanol and adipic acid [in the formula (III), R ⁵ = 4-CH ₃ , R ⁶ = 4-CH ₃ , p = 4 compound]
(F) etherified product of (7-oxabicyclo [4.1.0] hept-3-yl) methanol and 1,2-ethanediol [in the formula (V), R ⁹ = R ¹⁰ = H, r = Two compounds].

  Moreover, as an aliphatic epoxy-type compound, polyglycidyl ether of an aliphatic polyhydric alcohol or its alkylene oxide addition product can be mentioned. More specifically, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, propylene Polyethers of polyether polyols obtained by adding one or more alkylene oxides (ethylene oxide or propylene oxide) to aliphatic polyhydric alcohols such as glycol diglycidyl ether, ethylene glycol, propylene glycol and glycerin Examples thereof include glycidyl ether.

  In the present invention, the epoxy compound may be used alone or in combination of two or more. It is preferable that the active energy ray-curable resin composition contains at least an alicyclic epoxy-based compound because an excellent protective layer is obtained due to adhesion to the polarizing film and the retardation plate.

  In the active energy ray-curable resin composition used in the present invention, the epoxy compound is preferably contained in the active energy ray-curable compound in a proportion of 30 to 70% by weight, and a proportion of 40 to 60% by weight. More preferably, it is contained. When the content of the epoxy compound is less than 30% by weight, the adhesion with the polarizing film tends to be reduced, and when it exceeds 70% by weight, the optical performance is deteriorated due to yellowing of the cured film. Tend.

  Moreover, you may add an oxetane type compound with the said epoxy type compound to the active energy ray-curable resin composition used by this invention. By adding an oxetane compound, the viscosity of the active energy ray-curable resin composition can be lowered and the curing rate can be increased. Moreover, yellowing of a cured film can be prevented and optical performance can be improved.

  An oxetane compound is a compound having a 4-membered ring ether in the molecule, such as 3-ethyl-3-hydroxymethyloxetane, 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] benzene, Examples include 3-ethyl-3- (phenoxymethyl) oxetane, di [(3-ethyl-3-oxetanyl) methyl] ether, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, and phenol novolac oxetane. . These oxetane compounds can be easily obtained as commercial products. For example, all of these oxetane compounds are trade names such as “Aron Oxetane OXT-101”, “Aron Oxetane OXT-121”, “Aron Oxetane OXT-211”. , “Aron Oxetane OXT-221”, “Aron Oxetane OXT-212” (manufactured by Toagosei Co., Ltd.), and the like.

  Although the compounding quantity of an oxetane type compound is not specifically limited, Usually, it is 5 to 30 weight% in an active energy ray hardening compound, Preferably it is 10 to 25 weight%.

  When the active energy ray-curable resin composition used in the present invention contains a cationic curable compound such as an epoxy compound or an oxetane compound, the active energy ray curable resin composition includes a photocationic polymerization initiator. Is preferably blended. When a cationic photopolymerization initiator is used, it becomes possible to form a protective layer at room temperature, so the need to consider the heat resistance of the polarizing film or distortion due to expansion is reduced, and the protective layer is placed on the polarizing film with good adhesion. Can be formed. Moreover, since a photocationic polymerization initiator acts catalytically by light, it is excellent in storage stability and workability even when mixed with an active energy ray-curable resin composition.

  The cationic photopolymerization initiator generates a cationic species or a Lewis acid upon irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and initiates a polymerization reaction of an epoxy compound and / or an oxetane compound. Is. In the present invention, any type of cationic photopolymerization initiator may be used, but it is preferable from the viewpoint of workability that latency is imparted. Although it does not specifically limit as a photocationic polymerization initiator, For example, aromatic diazonium salt, aromatic iodonium salt, onium salts, such as an aromatic sulfonium salt, an iron- allene complex etc. can be mentioned.

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

  Examples of aromatic sulfonium salts include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, 4,4′-bis [diphenylsulfonio] diphenyl sulfide bishexa. Fluorophosphate, 4,4′-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenyl sulfide, bishexafluoroantimonate, 4,4′-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenyl sulfide, bis Hexafluorophosphate, 7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone hexafluoroantimonate, 7- [di (p-tolui) ) Sulfonio] -2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate, 4-phenylcarbonyl-4′-diphenylsulfonio-diphenyl sulfide hexafluorophosphate, 4- (p-tert-butylphenylcarbonyl) -4′-diphenyl Sulfonio-diphenyl sulfide hexafluoroantimonate, 4- (p-tert-butylphenylcarbonyl) -4′-di (p-toluyl) sulfonio-diphenyl sulfide, tetrakis (pentafluorophenyl) borate and the like.

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

  These photocationic polymerization initiators can be easily obtained as commercial products. For example, “Kayarad PCI-220” and “Kayarad PCI-620” (Nippon Kayaku Co., Ltd. )), “UVI-6990” (manufactured by Union Carbide), “Adekaoptomer SP-150”, “Adekaoptomer SP-170” (manufactured by ADEKA, Inc.), “CI-5102”, “ "CIT-1370", "CIT-1682", "CIP-1866S", "CIP-2048S", "CIP-2064S" (Nippon Soda Co., Ltd.), "DPI-101", "DPI-102" , “DPI-103”, “DPI-105”, “MPI-103”, “MPI-105”, “BBI-101”, “BBI-102”, “BBI” 103 "," BBI-105 "," TPS-101 "," TPS-102 "," TPS-103 "," TPS-105 "," MDS-103 "," MDS-105 "," DTS-102 " , “DTS-103” (manufactured by Midori Chemical Co., Ltd.), “PI-2074” (manufactured by Rhodia), and the like.

  These cationic photopolymerization initiators may be used alone or in combination of two or more. Among these, especially aromatic sulfonium salts have ultraviolet absorption characteristics even in a wavelength region of 300 nm or more, so they have excellent curability, good mechanical strength, and good adhesion to polarizing films and retardation plates. Since a hardened | cured material can be given, it is used preferably.

  The compounding quantity of a photocationic polymerization initiator is 0.5-20 weight part normally with respect to 100 weight part of total amounts of an epoxy-type compound and an oxetane type compound, Preferably it is 1-6 weight part. When the blending amount of the cationic photopolymerization initiator is less than 0.5 parts by weight with respect to 100 parts by weight of the total amount of the epoxy compound and the oxetane compound, curing becomes insufficient, and mechanical strength, protective layer and polarization There exists a tendency for the adhesiveness with a film and / or a phase difference plate to fall. Moreover, when the compounding quantity of a photocationic polymerization initiator exceeds 20 weight part with respect to 100 weight part of total amounts of an epoxy-type compound and an oxetane type compound, hardened | cured material will increase by the ionic substance in hardened | cured material increasing. There is a possibility that the hygroscopicity of the resin becomes higher and the durability performance is lowered.

  In addition, the active energy ray-curable resin composition used in the present invention is a (meth) acrylic compound having one or more (meth) acryloyloxy groups in the molecule (hereinafter simply referred to as (meta). )) (Sometimes referred to as an acrylic compound). By using the (meth) acrylic compound in combination, it is possible to obtain a protective layer having high hardness and excellent mechanical strength and higher durability. In addition, adjustment of the viscosity and curing rate of the active energy ray-curable resin composition, the surface curability of the protective layer to be obtained, and the adhesion to the polarizing film and the retardation film can be more easily performed. . Here, the “(meth) acryloyloxy group” means a methacryloyloxy group or an acryloyloxy group. The term “(meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule” means that at least one methacryloyloxy group or acryloyloxy group is in the molecule, and radical photopolymerization is initiated. It means a methacrylic acid ester derivative or an acrylic acid ester derivative that can be cured by irradiation with active energy rays (for example, ultraviolet rays, visible light, electron beams, X-rays, etc.) in the presence of an agent.

  Examples of the (meth) acrylic compound having one or more (meth) acryloyloxy groups in the molecule include (meth) acrylate monomers having one or more (meth) acryloyloxy groups in the molecule (hereinafter referred to as (meth) And (meth) acryloyloxy group-containing compounds such as (meth) acrylate oligomers (hereinafter referred to as (meth) acrylate oligomers) having two or more (meth) acryloyloxy groups in the molecule. Can do. These may be used alone or in combination of two or more. The “(meth) acrylate monomer” means an acrylate monomer or a methacrylate monomer, and the “(meth) acrylate oligomer” means an acrylate oligomer or a methacrylate oligomer.

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

  Specific examples of monofunctional (meth) acrylate monomers include tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy- 3-phenoxypropyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, benzyl (meth) acrylate , Isobornyl (meth) acrylate, phenoxyethyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, ethyl cal Tall (meth) acrylate, trimethylolpropane mono (meth) acrylate, pentaerythritol mono (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate and the like.

  Moreover, a carboxyl group-containing (meth) acrylate monomer may be used as the monofunctional (meth) acrylate monomer. Examples of the carboxyl group-containing monofunctional (meth) acrylate monomer include 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, carboxyethyl (meth) acrylate, and 2- (meth). Examples include acryloyloxyethyl succinic acid, N- (meth) acryloyloxy-N ′, N′-dicarboxy-p-phenylenediamine, 4- (meth) acryloyloxyethyl trimellitic acid, and the like. Moreover, as a monofunctional (meth) acrylate monomer, a (meth) acryloylamino group-containing monomer such as 4- (meth) acryloylamino-1-carboxymethylpiperidine can be used.

  Examples of the bifunctional (meth) acrylate monomer include alkylene glycol di (meth) acrylates, polyoxyalkylene glycol di (meth) acrylates, halogen-substituted alkylene glycol di (meth) acrylates, and aliphatic polyol di (meth). Di (meth) acrylates of acrylates, hydrogenated dicyclopentadiene or tricyclodecane dialkanol, di (meth) acrylates of dioxane glycol or dioxane dialkanol, di (meth) alkylene oxide adducts of bisphenol A or bisphenol F ) Acrylates, bisphenol A or bisphenol F epoxy di (meth) acrylates and the like are typical, but not limited thereto, and various ones can be used.

  More specific examples of the bifunctional (meth) acrylate monomer include ethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1 , 6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol di (meth) acrylate, ditri Methylolpropane di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polyethylene Glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, silicon di (meth) acrylate, hydroxypivalate ester neopentyl glycol di (meth) acrylate, 2,2-bis [4- (Meth) acryloyloxyethoxyethoxyphenyl] propane, 2,2-bis [4- (meth) acryloyloxyethoxyethoxycyclohexyl] propane, hydrogenated dicyclopentadienyl di (meth) acrylate, tricyclodecandi Methanol di (meth) acrylate, 1,3-dioxane-2,5-diyl di (meth) acrylate [also known as dioxane glycol di (meth) acrylate], hydroxypivalaldehyde and trimethylol group Di (meth) acrylate, tris (hydroxyethyl) of acetal compound [chemical name: 2- (2-hydroxy-1,1-dimethylethyl) -5-ethyl-5-hydroxymethyl-1,3-dioxane] with bread ) Isocyanurate di (meth) acrylate and the like.

  Examples of the polyfunctional (meth) acrylate monomer include glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth). ) Acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. ) Acrylate is typical, and in addition, poly (meth) acrylates of tri- or higher functional halogen-substituted polyols, glycerin alkylene oxide adducts Tri (meth) acrylate, trimethylolpropane alkylene oxide adduct tri (meth) acrylate, 1,1,1-tris [(meth) acryloyloxyethoxyethoxy] propane, tris (hydroxyethyl) isocyanurate tri (meth) Examples include acrylates and silicon hexa (meth) acrylate.

  As the (meth) acrylate oligomer, a bifunctional or higher urethane (meth) acrylate oligomer (hereinafter referred to as a polyfunctional urethane (meth) acrylate oligomer), a bifunctional or higher polyester (meth) acrylate oligomer (hereinafter referred to as a polyfunctional polyester). (Meth) acrylate oligomer.) Bifunctional or higher functional epoxy (meth) acrylate oligomer (hereinafter referred to as polyfunctional epoxy (meth) acrylate oligomer). Only one type of (meth) acrylate oligomer may be used, or two or more types may be used in combination.

  Examples of the polyfunctional urethane (meth) acrylate oligomer include a urethanation reaction product of a (meth) acrylate monomer having at least one (meth) acryloyloxy group and a hydroxyl group in the molecule and a polyisocyanate, and a polyisocyanate. And urethanation reaction products of an isocyanate compound obtained by reaction with (meth) acrylate monomer having at least one (meth) acryloyloxy group and one or more hydroxyl groups in the molecule.

  Examples of the (meth) acrylate monomer having one or more (meth) acryloyloxy groups and hydroxyl groups in the molecule used for the urethanization reaction include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (Meth) acrylate etc. are mentioned.

  The polyisocyanate used in the urethanization reaction is obtained by hydrogenating aromatic methylene diisocyanates, hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate. Diisocyanate (for example, diisocyanates such as hydrogenated tolylene diisocyanate and hydrogenated xylylene diisocyanate), di- or tri-isocyanate such as triphenylmethane triisocyanate, dimethylene triphenyl triisocyanate, and the like, and obtained by quantifying diisocyanate And polyisocyanates that can be used.

  As the polyols used for the reaction with the polyisocyanate, polyester polyols, polyether polyols and the like can be used in addition to aromatic, aliphatic and alicyclic polyols. Aliphatic and alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylol ethane, trimethylol propane, ditriol. Examples include methylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, and hydrogenated bisphenol A.

  The polyester polyol is obtained by a dehydration condensation reaction between the polyol and a polybasic carboxylic acid or an anhydride thereof. Polybasic carboxylic acids or their anhydrides include (anhydrous) succinic acid, adipic acid, (anhydrous) maleic acid, (anhydrous) itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, hexahydro (anhydrous) ) Phthalic acid, (anhydrous) phthalic acid, isophthalic acid, terephthalic acid and the like.

  As said polyether polyol, the polyoxyalkylene modified polyol obtained by reaction of the said polyols or dihydroxybenzenes and alkylene oxide other than polyalkylene glycol is mentioned.

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

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

  In the active energy ray-curable resin composition used in the present invention, the (meth) acrylic compound is preferably contained in a proportion of 30 to 70% by weight in the active energy ray-curable compound. % Is more preferable, and 40 to 60% by weight is more preferable. When the content of the (meth) acrylic compound is less than 30% by weight, the optical performance tends to decrease due to yellowing of the cured film. When the content exceeds 70% by weight, the adhesiveness to the polarizing film is increased. Tends to decrease.

  The active energy ray-curable resin composition used in the present invention preferably contains a radical photopolymerization initiator. The radical photopolymerization initiator is not particularly limited as long as it can start curing of the radical curable compound by irradiation with active energy rays, and a conventionally known one can be used. Specific examples of the radical photopolymerization initiator are not particularly limited. For example, acetophenone, 3-methylacetophenone, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1- Acetophenone-based initiators including ON, 2-methyl-1- [4- (methylthio) phenyl-2-morpholinopropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one; Benzophenone initiators such as benzophenone, 4-chlorobenzophenone, 4,4'-diaminobenzophenone, benzoin ether initiators including benzoinpropyl ether and benzoin ethyl ether; thioxanthones such as 4-isopropylthioxanthone Initiator Other, it is xanthone, fluorenone, camphor quinone, benzaldehyde, anthraquinone, such as.

  The compounding quantity of radical photopolymerization initiator is 0.5-20 weight part normally with respect to 100 weight part of (meth) acrylic-type compounds, Preferably it is 1-6 weight part. When the blending amount of the radical photopolymerization initiator is less than 0.5 parts by weight with respect to 100 parts by weight of the (meth) acrylic compound, curing becomes insufficient, and mechanical strength, a protective layer, a polarizing film, and / or There is a tendency for the adhesion to the retardation plate to decrease. Moreover, when the compounding quantity of radical photopolymerization initiator exceeds 20 weight part with respect to 100 weight part of (meth) acrylic-type compounds, the hygroscopic property of hardened | cured material is high because the ionic substance in hardened | cured material increases. Thus, the durability performance may be reduced.

  The active energy ray-curable resin composition can further contain a photosensitizer as necessary. By using a photosensitizer, the reactivity of cationic polymerization and / or radical polymerization is improved, and the mechanical strength of the protective layer and the adhesion between the protective layer and the polarizing film and / or the retardation film are improved. Can do. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, and photoreductive dyes. Specific photosensitizers include, for example, benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether, α, α-dimethoxy-α-phenylacetophenone; benzophenone, 2,4-dichlorobenzophenone, o-benzoylbenzoic acid. Benzophenone derivatives such as methyl, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone; thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone; 2-chloroanthraquinone, Anthraquinone derivatives such as 2-methylanthraquinone; acridone derivatives such as N-methylacridone and N-butylacridone; other, α, α-diethoxyacetophenone, benzyl, fluorenone, quinone Sandton, uranyl compounds, halogen compounds and the like can be mentioned, but are not limited thereto. These may be used alone or in combination. The photosensitizer is preferably contained in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the active energy ray-curable compound.

  Moreover, the active energy ray-curable resin composition may contain an antistatic agent for imparting antistatic performance to the polarizing plate. The antistatic agent is not particularly limited, and a known antistatic agent can be used. For example, cationic surfactants such as acyloylamidopropyldimethylhydroxyethylammonium nitrate, acyloylamidopropyltrimethylammonium sulfate, cetylmorpholium methosulfate; linear alkyl phosphate potassium salt, polyoxyethylene alkyl phosphorus Anionic surfactants such as acid potassium salts and alkane sulfonates; nonionics such as N, N-bis (hydroxyethyl) -N-alkylamines, fatty acid ester derivatives thereof, polyhydric alcohol fatty acid partial esters A surface active agent or the like can be used. The blending ratio of these antistatic agents is appropriately determined according to desired properties, but is usually about 0.1 to 10 parts by weight with respect to 100 parts by weight of the active energy ray-curable compound.

  To the active energy ray-curable resin composition, a known polymer additive usually used for polymers can be added. Examples include primary antioxidants such as phenols and amines, sulfur secondary antioxidants, hindered amine light stabilizers (HALS), benzophenone, benzotriazole, and benzoate UV absorbers. It is done.

  Silica fine particles may be added to the active energy ray-curable resin composition. By adding silica fine particles, the hardness and mechanical strength of the protective layer obtained can be further improved. Silica fine particles can be blended in the active energy ray-curable resin composition, for example, as a liquid dispersed in an organic solvent.

  The silica fine particles may have a reactive functional group such as a hydroxyl group, an epoxy group, a (meth) acryloyl group, or a vinyl group on the surface thereof. The particle size of the silica fine particles is usually 100 nm or less, preferably about 5 to 50 nm. When the particle diameter of the fine particles exceeds 100 nm, an optically transparent protective layer tends to be not obtained.

  In the case of using silica fine particles dispersed in an organic solvent, the silica concentration is not particularly limited, and a commercially available product, for example, about 20 to 40% by weight can be used.

  Examples of silica fine particles dispersed in an organic solvent available as a commercial product include, for example, “methanol silica sol” (manufactured by Nissan Chemical Industries, Ltd., silica particle size of 10 to 15 nm, solid content of 30 wt. %), “MA-ST-M” (manufactured by Nissan Chemical Industries, Ltd., silica particle size 20 to 25 nm, solid content 40% by weight), “OSCAL 1132” (manufactured by Catalyst Chemical Industry Co., Ltd., silica particle size 10) "OSCAL 1232" (catalyst chemical industry Co., Ltd., silica particle size 10 to 20 nm, solid content 30 to 31 wt%); organic solvent, organic solvent is ethyl alcohol “OSCAL 1332” (produced by Catalytic Chemical Industry Co., Ltd., silica particle size 10 to 20 nm, solid content 30 to 31 wt%); “IPA-ST” which is sopropyl alcohol (manufactured by Nissan Chemical Industries, Ltd., silica particle size 10 to 15 nm, solid content 30% by weight), “OSCAL 1432” (manufactured by Catalyst Chemical Industries, Ltd., silica particle size 10 ˜20 nm, solid content 30-31 wt%); “NBA-ST” (Nissan Chemical Industry Co., Ltd., silica particle size 10-15 nm, solid content 20 wt%), where the organic solvent is n-butyl alcohol, “ "OSCAL 1532" (manufactured by Catalytic Chemical Industry Co., Ltd., silica particle size 10 to 20 nm, solid content 30 to 31 wt%); "EG-ST" (Nissan Chemical Industry Co., Ltd., silica, whose organic solvent is ethylene glycol) “OSCAL 1632” (catalyst chemical industry Co., Ltd., silica particle size 10 to 20 nm, solid content 3) whose organic solvent is ethyl cellosolve “NPC-ST” (manufactured by Nissan Chemical Industries, Ltd., silica particle size 10 to 15 nm, solid content 30% by weight); organic solvent is dimethyl “DMAC-ST” (manufactured by Nissan Chemical Industries, silica particle size 10-15 nm, solid content 20% by weight), “DMAC-ST-ZL” (manufactured by Nissan Chemical Industries, silica particle size) "XBA-ST" (Nissan Chemical Industry Co., Ltd., silica particle size 10-15 nm, solid content 30% by weight, organic solvent is a mixture of xylene and n-butyl alcohol) "MIBK-ST" (manufactured by Nissan Chemical Industries, silica particle size 10-15 nm, solid content 30% by weight); the organic solvent is methyl ethyl “MEK-ST” (manufactured by Nissan Chemical Industries, silica particle size 10-15 nm, solid content 30% by weight), “SP-1120” (manufactured by Konishi Chemical Industries, silica particle size 15- 20 nm, solid content 5 to 10% by weight), “SP-6120” (manufactured by Konishi Chemical Industry Co., Ltd., silica particle size 15 to 20 nm, solid content 5 to 10% by weight) and the like. Two or more kinds can be suitably used. In addition, “Snowtex 20” whose dispersion medium is water (Nissan Chemical Industry Co., Ltd., silica particle size 10-20 nm) “Snowtex C” (Nissan Chemical Industry Co., Ltd., silica particle size 10-20 nm) ) Etc. can also be used.

  The silica fine particles are preferably added in an amount of 5 to 250 parts by weight, more preferably 10 to 100 parts by weight, with respect to 100 parts by weight of the active energy ray curable compound contained in the active energy ray curable resin composition. It is. When the addition amount of the fine particles is less than 5 parts by weight with respect to 100 parts by weight of the active energy ray-curable compound, the improvement in the hardness of the protective layer due to the addition of the fine particles may not be sufficient. On the other hand, when the addition amount of fine particles exceeds 250 parts by weight with respect to 100 parts by weight of the active energy ray-curable compound, the adhesion between the polarizing film and the protective layer may be lowered. Moreover, when the addition amount of the fine particles exceeds 250 parts by weight, the dispersion stability of the fine particles in the active energy ray-curable resin composition may be decreased, or the viscosity of the resin composition may be excessively increased. .

  Furthermore, the active energy ray-curable resin composition may contain a solvent as necessary. A solvent is suitably selected by the solubility of the component which comprises an active energy ray 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; esters such as methyl acetate, ethyl acetate and butyl acetate; cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve; halogens such as methylene chloride and chloroform Hydrocarbons and the like. The mixing ratio of the solvent is appropriately determined from the viewpoint of adjusting the viscosity depending on the processing purpose such as film formability.

  Although it does not specifically limit as a method of producing the polarizing plate of this invention which has a polarizing film, a 1st protective layer, and a phase difference plate in this order, The said active energy ray curable resin composition is made into the single side | surface of a polarizing film. After coating, a retardation plate is bonded onto a coating film (coating film serving as the first protective layer) made of the active energy ray-curable resin composition, and then the active energy beam is irradiated to the coating. The method of hardening a film | membrane can be mentioned. When the second protective layer is formed on the surface of the polarizing film opposite to the side having the first protective layer, the active energy ray-curable resin composition is also applied to the surface. At this time, the composition of the active energy ray-curable resin composition used for the first protective layer and the second protective layer may be the same or different.

  As another polarizing plate manufacturing method, after coating an active energy ray-curable resin composition on one surface of a retardation plate to form a coating film on the retardation plate, the coating film becomes a bonding surface. Thus, the method of sticking a phase difference plate to a polarizing film and then irradiating an active energy ray to cure the coating film can be mentioned. Similarly, the second protective layer is formed by coating the active energy ray-curable resin composition on another film different from the polarizing film (for example, a polyethylene terephthalate film), and coating the other film. After forming, the other film may be bonded to the polarizing film so that the coating film becomes a bonding surface. In this case, the other film is peeled after irradiating the active energy ray to obtain the second protective layer. By the production method as described above, it is possible to obtain a polarizing plate in which the polarizing film, the protective layer, and the retardation plate are directly bonded without passing through other layers (for example, an adhesive layer or a pressure-sensitive adhesive layer).

  Here, the phase difference plate is used for the purpose of compensating for the phase difference by the liquid crystal cell. Examples thereof include a birefringent film made of a stretched film of various plastics, a film in which a discotic liquid crystal or a nematic liquid crystal is oriented and fixed, and a film substrate on which the above liquid crystal layer is formed. In this case, a cellulose-based film such as triacetyl cellulose is preferably used as the film substrate that supports the oriented liquid crystal layer.

  Specific examples of the plastic forming the birefringent film include polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polyolefin such as polypropylene, polyarylate, polyamide and the like. The stretched film may be processed by an appropriate method such as uniaxial or biaxial. Moreover, the birefringent film which controlled the refractive index of the thickness direction of a film by applying shrinkage force and / or extending | stretching force under adhesion | attachment with a heat-shrinkable film may be sufficient. Note that two or more retardation plates may be used in combination for the purpose of controlling optical characteristics such as broadening the bandwidth.

  Moreover, although a phase difference plate may be used for manufacture of the polarizing plate which concerns on this invention as it is, you may perform a corona discharge process and a plasma process to the bonding surface with the coating film which forms a protective layer.

  The means for applying the active energy ray curable resin composition to a polarizing film or a retardation plate is not particularly limited, and various coatings such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used. Construction method can be used. In addition, since each coating method has an optimum viscosity range, it is also a useful technique to adjust the viscosity using a solvent. Examples of the solvent for this purpose include those described above.

The light source used for the irradiation of the active energy ray is not particularly limited, but has a light emission distribution at a wavelength of 400 nm or less, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, microwave excitation A mercury lamp, a metal halide lamp, etc. can be used. The light irradiation intensity to the active energy ray-curable resin composition may vary depending on the composition, but the irradiation intensity in the wavelength region effective for the activation of the photocationic polymerization initiator and / or the photoradical polymerization initiator is 10 It is preferably ˜2500 mW / cm ² . When the light irradiation intensity to the active energy ray curable resin composition is less than 10 mW / cm ² , the reaction time becomes too long, and when it exceeds 2500 mW / cm ² , the heat radiated from the lamp and the active energy ray curable property. There is a possibility that yellowing of the active energy ray-curable resin composition or deterioration of the polarizing film may occur due to heat generation during polymerization of the resin composition. The light irradiation time to the active energy ray-curable resin composition is controlled for each composition and is not particularly limited, but the integrated light amount expressed as the product of the irradiation intensity and the irradiation time is 10. It is preferably set to be ˜2500 mJ / cm ² . If the integrated light amount to the active energy ray-curable resin composition is less than 10 mJ / cm ² , the generation of active species derived from the polymerization initiator is not sufficient, and the resulting protective layer may be insufficiently cured. is there. On the other hand, if the integrated light quantity exceeds 2500 mJ / cm ² , the irradiation time becomes very long, which is disadvantageous for improving productivity. In addition, it is preferable that irradiation of an active energy ray is performed in the range in which various performances, such as the polarization degree and transmittance | permeability of a polarizing film, do not fall.

  The thickness of the protective layer is preferably as thin as possible in view of thinness and lightness. However, if the thickness is too thin, the polarizing film cannot be sufficiently protected, and handling properties are lacking. Therefore, the thickness of the protective layer is preferably about 40 μm or less, more preferably about 15 μm or less.

  When a polarizing plate has a 2nd protective layer, you may provide an optical function layer on the 2nd protective layer as needed. Here, the optical functional layer is a hard coat in addition to laminating a layer (film) such as a reflective layer, a transflective reflective layer, a light diffusing layer, a light collector, and a brightness enhancement film on the second protective layer. It also includes subjecting the second protective layer to surface treatment such as treatment, antireflection treatment, and antiglare treatment, and laminating another film subjected to these surface treatments on the second protective layer. The reflective layer, transflective reflective layer, and light diffusing layer are used when forming a reflective or transflective or diffusive polarizing plate.

  The reflective polarizing plate is used in a liquid crystal display device of a type that reflects and displays incident light from the viewing side. Since a light source such as a backlight can be omitted, the liquid crystal display device can be easily thinned. The transflective polarizing plate is used in a liquid crystal display device of a type in which a reflective type is used in a bright place and a light source such as a backlight is used in a dark place.

  The reflective layer can be formed, for example, by providing a foil or a vapor deposition film made of a metal such as aluminum on the second protective layer of the polarizing plate, whereby a reflective polarizing plate can be obtained. The semi-transmissive reflective layer can be formed by providing a reflective plate on the second protective layer that includes a reflective layer that is a half mirror or contains a pearl pigment or the like and that exhibits light transmittance. A type of polarizing plate can be obtained. The light diffusion layer can be formed by a method of performing a mat treatment on the second protective layer, a method of applying a resin containing fine particles, a method of adhering a film containing fine particles, and the like. A board can be obtained. .

  The reflection / diffusion polarizing plate can be obtained by, for example, a method of providing a reflective layer reflecting the concavo-convex structure on the fine concavo-convex structure surface of the diffusion polarizing plate. The reflective layer having a fine concavo-convex structure has advantages such that incident light is diffused by irregular reflection, directivity and glare can be prevented, and unevenness in brightness and darkness can be suppressed. In addition, the resin layer or film containing fine particles also has an advantage that incident light and its reflected light are diffused when passing through the layer and light and dark unevenness can be further suppressed. The reflective layer reflecting the surface fine concavo-convex structure can be formed, for example, by directly attaching a metal to the surface of the fine concavo-convex structure by a method such as vacuum deposition, ion plating, sputtering, or the like, or plating. Examples of the fine particles to be blended to form the surface fine concavo-convex structure include silica, aluminum oxide, titanium oxide, zirconia, tin oxide, indium oxide, cadmium oxide, and antimony oxide having an average particle size of 0.1 to 30 μm. Inorganic fine particles composed of, etc., organic fine particles composed of a crosslinked or uncrosslinked polymer, etc. can be used.

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

  The brightness enhancement film is used for the purpose of improving the brightness in a liquid crystal display device or the like. For example, a plurality of thin film films having different refractive index anisotropies are laminated to produce anisotropy in reflectance. And a reflection-type polarization separation sheet designed in the above, a cholesteric liquid crystal polymer alignment film, and a circular polarization separation sheet in which the alignment liquid crystal layer is supported on a film substrate.

  The optical function layer may be used alone or in combination of two or more. Moreover, you may arrange | position two or more layers, respectively, for a light-diffusion layer, a light-condensing plate, and a brightness improvement film. In addition, there is no limitation in particular in arrangement | positioning of each optical function layer.

  When the second protective layer has an adhesive force to the optical functional layer, the optical functional layer may be bonded to the second protective layer by directly bonding both of them. Alternatively, it can be carried out using an adhesive or a pressure-sensitive adhesive. An adhesive or a pressure-sensitive adhesive can also be used for bonding between the optical function layers. It is preferable to use a pressure-sensitive adhesive (also referred to as a pressure-sensitive adhesive) from the viewpoint of easy bonding work and prevention of optical distortion. As the adhesive, an acrylic polymer, a silicone polymer, polyester, polyurethane, polyether, or the like can be used as a base polymer. Among them, like acrylic adhesives, it has excellent optical transparency, retains appropriate wettability and cohesion, has excellent adhesion, and has weather resistance, heat resistance, etc. It is preferable to select and use a material that does not cause peeling problems such as floating and peeling under humidification conditions. In acrylic adhesives, alkyl esters of (meth) acrylic acid having an alkyl group having 20 or less carbon atoms such as methyl, ethyl and butyl groups, and (meth) acrylic acid and hydroxyethyl (meth) acrylate An acrylic copolymer having a weight average molecular weight of 100,000 or more, in which a glass transition temperature is preferably 25 ° C. or less, more preferably 0 ° C. or less, and a functional group-containing acrylic monomer comprising Useful as a base polymer.

  Moreover, in the polarizing plate of this invention, you may provide an adhesive layer on a phase difference plate. Such an adhesive layer can be used, for example, for bonding with a liquid crystal cell. For example, the pressure-sensitive adhesive layer is formed by dissolving or dispersing the pressure-sensitive adhesive composition such as the base polymer as described above in an organic solvent such as toluene or ethyl acetate to prepare a 10 to 40% by weight solution. Form a pressure-sensitive adhesive layer by coating directly on a phase difference plate, or form a pressure-sensitive adhesive layer by previously forming a pressure-sensitive adhesive layer on a protective film and transferring it to the phase difference plate This can be done by a method or the like. Although the thickness of an adhesive layer is determined according to the adhesive force etc., it is the range of 1-50 micrometers normally.

  If necessary, the adhesive layer may contain fillers made of glass fiber, glass beads, resin beads, inorganic powders such as metal powder, pigments, colorants, antioxidants, UV absorbers, etc. Good. Examples of ultraviolet absorbers include salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, nickel complex compounds, and the like.

  The polarizing plate of the present invention can be suitably applied to a liquid crystal display device. FIG. 1 is a schematic sectional view showing an example of a liquid crystal display element using the polarizing plate of the present invention. The liquid crystal display element shown in FIG. 1 has two polarizing plates bonded to both surfaces of a liquid crystal cell 1 via an adhesive layer 7. One polarizing plate (the upper polarizing plate in FIG. 1) is a polarizing plate disposed on the viewing side when mounted on the liquid crystal display device, and from the liquid crystal cell 1 side, the retardation plate 4 / first protection. It has the structure of layer 3a / polarizing film 2 / second protective layer 3b / surface treatment layer 5. The other polarizing plate (the lower polarizing plate in FIG. 1) is a polarizing plate disposed on the backlight side when mounted on the liquid crystal display device. From the liquid crystal cell 1 side, the retardation plate 4 / It has the structure of 1st protective layer 3a / polarizing film 2 / second protective layer 3b / brightness enhancement film 6.

  The type of liquid crystal cell used in the liquid crystal display device of the present invention is not particularly limited. For example, an active matrix drive type represented by a thin film transistor type, a simple matrix drive type represented by a super twisted nematic type, etc. Various liquid crystal cells can be used. The polarizing plates provided on both sides of the liquid crystal cell may be the same or different as shown in FIG. Moreover, the polarizing plate may be disposed only on one side of the liquid crystal cell.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited by these examples. In the examples, “parts” and “%” representing the amount used or content are based on weight unless otherwise specified.

(Production Example 1: Production of polarizing film)
A 75 μm-thick polyvinyl alcohol film (average polymerization degree: 1700, saponification degree: 99.9 mol% or more) was subjected to uniaxial stretching at a draw ratio of 5 times, and iodine and potassium iodide were kept in a tension state. It was immersed for 60 seconds in the aqueous solution containing (iodine: potassium iodide: water = 0.05: 5: 100 (weight ratio)). Next, it is immersed in a 65 ° C. aqueous solution containing potassium iodide and boric acid (potassium iodide: boric acid: water = 2.5: 7.5: 100 (weight ratio)) for 300 seconds to perform boric acid treatment. It was. Next, after washing with pure water at 25 ° C. for 20 seconds and drying at 50 ° C., a polarizing film in which iodine was adsorbed and oriented on a uniaxially stretched polyvinyl alcohol resin film was obtained (thickness 30 μm).

(Production Example 2: Preparation of active energy ray-curable resin composition I)
The following components were mixed to obtain an active energy ray-curable resin composition I.

3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (Daicel Chemical Industries, Celoxide 2021P) 35 parts Bis (3-ethyl-3-oxetanylmethyl) ether (Toagosei Co., Ltd., Aron) Oxetane OXT-221) 15 parts Tricyclodecane dimethanol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-DCP) 50 parts 2-hydroxy-2-methyl-1-phenylpropan-1-one (Ciba Specialty)・ Chemicals, DAROCURE 1173, radical photopolymerization initiator)
2.25 parts 4,4′-bis [diphenylsulfonio] diphenyl sulfide Bishexafluorophosphate-based photocationic polymerization initiator (manufactured by ADEKA, SP-150) 2.25 parts (Production Example 3: Active energy) Preparation of linear curable resin composition II)
The following components were mixed to obtain an active energy ray-curable resin composition II.

3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (Daicel Chemical Industries, Celoxide 2021P) 35 parts Bis (3-ethyl-3-oxetanylmethyl) ether (Toagosei Co., Ltd., Aron) Oxetane OXT-221) 15 parts Diacrylate of acetal compound of hydroxypivalaldehyde and trimethylolpropane (Shin-Nakamura Chemical Co., Ltd., A-DOG) 50 parts 2-hydroxy-2-methyl-1-phenylpropane -1-one (Ciba Specialty Chemicals, DAROCURE 1173, photo radical polymerization initiator)
2.25 parts 4,4′-bis [diphenylsulfonio] diphenyl sulfide Bishexafluorophosphate-based photocationic polymerization initiator (manufactured by ADEKA, SP-150) 2.25 parts The above A-DOG (Diacrylate of an acetal compound of hydroxypivalaldehyde and trimethylolpropane) is a compound having a structure of the following formula.

(Production Example 4: Preparation of active energy ray-curable resin composition III)
The following components were mixed to obtain an active energy ray-curable resin composition III.

3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (Daicel Chemical Industries, Celoxide 2021P) 35 parts Bis (3-ethyl-3-oxetanylmethyl) ether (Toagosei Co., Ltd., Aron) Oxetane OXT-221) 15 parts 2-hydroxy-3-phenoxypropyl acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., 702A) 50 parts 2-hydroxy-2-methyl-1-phenylpropan-1-one (Ciba Specialty)・ Chemicals, DAROCURE 1173, radical photopolymerization initiator)
2.25 parts 4,4′-bis [diphenylsulfonio] diphenyl sulfide Bishexafluorophosphate-based photocationic polymerization initiator (manufactured by ADEKA, SP-150)
2.25 parts (Production Example 5: Preparation of active energy ray-curable resin composition IV)
The following components were mixed to obtain an active energy ray-curable resin composition IV.

Diglycidyl ether of hydrogenated bisphenol A (Epicoat YX8000, manufactured by Japan Epoxy Resin Co., Ltd.) 100 parts 4,4′-bis [diphenylsulfonio] diphenyl sulfide Bishexafluorophosphate-based photocationic polymerization initiator ((Strain ) Made by ADEKA, SP-150)
40 parts (Production Example 6: Preparation of active energy ray-curable resin composition V)
The following components were mixed to obtain an active energy ray-curable resin composition V.

70 parts 1,4-bis [{(3-ethyl-3-oxetanyl) methoxy} methyl] benzene (Toagosei Co., Ltd.) Diglycidyl ether of nuclear hydrogenated bisphenol A (Japan Epoxy Resin Co., Ltd., Epicoat YX8000) Manufactured by Alonoxetane OXT-121) 30 parts 4,4′-bis [diphenylsulfonio] diphenyl sulfide Bishexafluorophosphate-based photocationic polymerization initiator (manufactured by ADEKA, SP-150)
40 parts <Example 1>
An active energy ray obtained in Production Example 2 using a coating machine (manufactured by Daiichi Rika Co., Ltd., bar coater) on one side of a polyethylene terephthalate (PET) film (Easter Film E7002 manufactured by Toyobo Co., Ltd.) The curable resin composition I was applied. In addition, a corona discharge treatment was applied to one side of a retardation film made of norbornene-based resin (manufactured by Optes Co., Ltd., ZEONOR film, thickness 70 μm), and the active energy ray-curable resin composition I was applied to the same surface. did. At this time, since the film thickness when the active energy ray-curable resin composition was applied changed depending on the viscosity, the film thickness was adjusted by changing the number of the bar coater number. Next, a PET film having a coating film of the active energy ray-curable resin composition I on one surface of the polarizing film produced in Production Example 1, and the active energy ray-curable resin composition on the other surface. The phase difference plate having the coating film I was bonded using a bonding apparatus (manufactured by Fuji Plastic Co., Ltd., LPA3301) so that each coating film side became a bonding surface with the polarizing film.

The bonded product was irradiated with ultraviolet rays with an integrated light quantity of 1500 mJ / cm ² by a D bulb manufactured by Fusion UV Systems, and the active energy ray-curable resin composition I disposed on both surfaces of the polarizing film was cured. Thereafter, the PET film was peeled off to produce a polarizing plate having a retardation plate.

<Example 2>
A polarizing plate was produced in the same manner as in Example 1, except that the active energy ray-curable resin composition II obtained in Production Example 3 was used instead of the active energy ray-curable resin composition I.

<Example 3>
A polarizing plate was produced in the same manner as in Example 1 except that the active energy ray-curable resin composition III obtained in Production Example 4 was used instead of the active energy ray-curable resin composition I.

<Comparative Example 1>
A polarizing plate was produced in the same manner as in Example 1 except that instead of the active energy ray-curable resin composition I, the active energy ray-curable resin composition IV obtained in Production Example 5 was used.

<Comparative Example 2>
A polarizing plate was produced in the same manner as in Example 1 except that instead of the active energy ray curable resin composition I, the active energy ray curable resin composition V obtained in Production Example 6 was used.

<Comparative Example 3>
An active energy ray obtained in Production Example 4 using a coating machine (manufactured by Daiichi Rika Co., Ltd., bar coater) on one side of a polyethylene terephthalate (PET) film (Ester film E7002 manufactured by Toyobo Co., Ltd.) By coating curable resin composition III, two PET films having a coating film of active energy ray-curable resin composition III were produced. Next, the PET film is pasted on both surfaces of the polarizing film produced in Production Example 1 by using a pasting device (manufactured by Fuji Plastic Co., Ltd., LPA3301) so that the coating film side becomes a bonding surface with the polarizing film. Combined.

The bonded product was irradiated with ultraviolet rays with an integrated light quantity of 1500 mJ / cm ² using a D bulb manufactured by Fusion UV Systems, and the active energy ray-curable resin composition III disposed on both surfaces of the polarizer was cured. Thereafter, the PET film was peeled off to obtain a polarizing plate having protective layers on both sides (no retardation plate).

<Comparative example 4>
A polarizing plate in which a protective film made of triacetyl cellulose (TAC) having a thickness of 40 μm is bonded to both surfaces of a polarizing film (thickness 30 μm) in which iodine is adsorbed and oriented on a polyvinyl alcohol resin film (Sumitomo Chemical Co., Ltd.) A retardation film (thickness: 70 μm) made of the same norbornene resin as used in Example 1 was bonded to one side of TRW042A) through an adhesive to prepare a polarizing plate having a retardation plate.

  The following evaluation tests were conducted on the polarizing plates prepared in the above examples and comparative examples. The results are shown in Table 1.

In addition, the measuring method of each evaluation test is as follows.
[Measurement of thickness of polarizing plate]
Using the film thickness meter (Nikon Corporation, ZC-101), the entire polarizing plate produced (for Examples 1 to 3 and Comparative Examples 1, 2 and 4), the upper and lower protective layers, the polarizing film, and the retardation plate For the laminate of Comparative Example 3, the thickness of the upper and lower protective layers and the laminate of the polarizing film was measured and evaluated according to the following criteria.
A: The thickness is less than 100 μm,
B: The thickness is 100 μm or more and less than 125 μm,
C: The thickness is 125 μm or more and less than 150 μm,
D: The thickness is 150 μm or more.

[Adhesion test]
The following cross-hatch test was conducted for the adhesion between the protective layer and the polarizing film, and the following cutter test was conducted for the adhesion between the retardation plate and the protective layer.

(Cross hatch test)
For Examples 1 to 3 and Comparative Examples 1, 2, and 4, the retardation plate side was bonded to the glass via an adhesive, and the one protective layer side was bonded to the glass, respectively. Cut 100 squares of 1 mm square on the surface of the protective layer on the side with a cutter knife, apply cellophane tape to the surface, and perform a test to peel it off. I counted the number of. As a result, in any polarizing plate, the number of remaining grids was 100. In Table 1, “A” indicates that the number of remaining grids is 100/100.

(Cutter test)
Each polarizing plate was allowed to stand at room temperature for 1 hour, and then a cutter blade was inserted between the polarizing film and the phase difference plate, and how the blade entered when the blade was pushed forward was evaluated. As a result, the blades of the cutter hardly entered between the films for any of the polarizing plates (the polarizing plate of Comparative Example 3 is not subject to testing because it does not have a retardation plate). In Table 1, “A” indicates that the cutter blade hardly enters between the films.

[Dimensional stability test]
About each polarizing plate, the dimensional change after leaving still for 120 hours in a 85 degreeC dry environment was measured. That is, first, the polarizing plate was cut into a size of 8 cm × 8 cm, and was bonded to glass via an adhesive (the one on which the retardation plate was bonded was on the retardation plate side) to obtain a measurement sample. The sample was autoclaved for 1 hour at a temperature of 50 ° C. and a pressure of 5 kg / cm ² (490.3 kPa), and then left for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55%. The dimension in this state was defined as the initial dimension. Next, after allowing to stand in a dry environment at 85 ° C. for 120 hours, the dimensions in the machine direction (MD) and the transverse direction (TD) were measured using a two-dimensional dimension measuring device (manufactured by Nikon Corporation, NEXIV VMR-1207). The dimensional change rate was calculated from the following formula.
Dimension shrinkage (%) = {(Dimension after test−Initial dimension) / Initial dimension} × 100
Table 1 shows the dimensional change rate in the MD direction. The evaluation criteria for the dimensional change rate are as follows.
A: The dimensional change rate is less than 0.4% in absolute value,
B: The dimensional change rate is 0.4% or more and less than 0.5% in absolute value.
C: The dimensional change rate is 0.5% or more and less than 0.6% in absolute value,
D: The dimensional change rate is 0.6% or more in absolute value.

[Optical durability test]
About each polarizing plate, it left still in the environment of 85 degreeC drying or 60 degreeC relative humidity 90%, and the change of the optical performance in time passage was measured. That is, first, the polarizing plate was cut into a size of 3 cm × 3 cm, and each was bonded to glass via a pressure-sensitive adhesive (on the side of the retardation plate on the retardation plate side) to obtain a measurement sample. The sample was autoclaved for 1 hour at a temperature of 50 ° C. and a pressure of 5 kg / cm ² (490.3 kPa), and then left for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55%. For this sample, an optional accessory “film holder with polarizer” is set in the UV2450 UV-Vis spectrophotometer UV2450 manufactured by Shimadzu Corporation, and the transmission in the transmission direction and absorption direction of the polarizing plate in the wavelength range of 380 nm to 700 nm The spectrum was measured, and the degree of polarization Py, simple substance transmittance Ty, and simple substance b ^* , which is a simple substance hue, were determined according to JIS Z 8729. With the optical performance in this state as the initial stage, the optical performance after being dried for 24 hours in an environment of 85 ° C. drying or 60 ° C. relative humidity 90% is measured, and the degree of polarization change ΔPy, single transmittance change ΔTy, And the hue change Δb ^* was calculated.

ΔPy = (Py after test−initial Py)
ΔTy = (Ty after test−initial Ty)
Δb ^* = (b ^* after test−initial b ^* )
The evaluation criteria for the optical durability test are as follows. For ΔPy, A was evaluated when the amount of change was less than 1%, B was evaluated when it was 1% or more and less than 5%, and C was evaluated when it was 5% or more. For ΔTy, A was evaluated when the amount of change was less than 1%, B was evaluated when it was 1% or more and less than 5%, and C was evaluated when it was 5% or more. For Δb ^* , the case where the amount of change was less than 2% was evaluated as A, the case where it was 2% or more and less than 5% was evaluated as B, and the case where it was 5% or more was evaluated as C. Table 1 shows the evaluation results of ΔPy and Δb ^* when placed under drying at 85 ° C., and the evaluation results of ΔPy and ΔTy when placed in an environment of 60 ° C. and 90% relative humidity.

  From Table 1, the polarizing plate of the example shows dimensional stability superior to the polarizing plate of Comparative Example 3 while exhibiting optical durability comparable to the polarizing plates of Comparative Examples 3 and 4, and a retardation plate It can be seen that the thickness can be reduced even in the stacked state. In contrast, the polarizing plates of Comparative Examples 1 and 2 that do not contain a (meth) acrylic compound in the active energy ray-curable resin composition forming the protective layer did not have sufficient optical durability.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic sectional drawing which shows an example of the liquid crystal display element using the polarizing plate of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Liquid crystal cell, 2 Polarizing film, 3a 1st protective layer, 3b 2nd protective layer, 4 Phase difference plate, 5 Surface treatment layer, 6 Brightness improvement film, 7 Adhesive layer.

Claims (8)

A polarizing film, a first protective layer, and a retardation plate are laminated in this order,
The first protective layer includes an active energy ray-cured material including an epoxy compound having two or more epoxy groups in a molecule and a (meth) acryl compound having one or more (meth) acryloyloxy groups in the molecule. Polarizing plate made of a cured product of a conductive resin composition. A second protective layer laminated on the surface of the polarizing film opposite to the side on which the first protective layer is laminated;
The second protective layer includes an active energy ray-curing material including an epoxy compound having two or more epoxy groups in a molecule and a (meth) acryl compound having one or more (meth) acryloyloxy groups in the molecule. The polarizing plate according to claim 1, comprising a cured product of the conductive resin composition.   The polarizing plate according to claim 1, wherein the active energy ray-curable resin composition further contains an oxetane compound.   The polarizing plate according to claim 2, further comprising an optical functional layer laminated on the second protective layer.   The polarizing plate according to claim 4, wherein the optical functional layer is a brightness enhancement film or a surface treatment layer.   The polarizing plate according to any one of claims 1 to 5, further comprising an adhesive layer laminated on the retardation plate.   The polarizing plate according to claim 1, wherein the polarizing film is obtained by adsorbing and orienting a dichroic dye on a polyvinyl alcohol-based resin film.   A liquid crystal display device, wherein the polarizing plate according to claim 1 is disposed on one side or both sides of a liquid crystal cell.

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