JP2016066047A - Polarizing plate and liquid crystal panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarizing plate comprising a polarizer and a (meth)acrylic resin film laminated on both surfaces of the polarizer, which has sufficient durability (light fastness) and prevents mixture of foreign substances derived from a UV absorbent, and a liquid crystal panel using the polarizing plate.SOLUTION: The polarizing plate comprises a polarizer, a first (meth)acrylic resin film laminated on one surface of the polarizer, and a second (meth)acrylic resin film laminated on the other surface. The first (meth)acrylic resin film contains a UV absorbent and shows a transmittance of 20% or less in the entire wavelength region from 190 to 380 nm. The second (meth)acrylic resin film has a content of the UV absorbent of 1 wt.% or less. A liquid crystal panel using the polarizing plate is also disclosed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polarizing plate in which a (meth) acrylic resin film is bonded to both surfaces of a polarizer, and a liquid crystal panel using the polarizing plate.

  A polarizing plate is widely used as a polarized light supplying element and a polarized light detecting element in an image display device such as a liquid crystal display device. As a polarizing plate, the thing of the structure which bonded the protective film on the single side | surface or both surfaces of the polarizer using the adhesive agent is common.

  Patent Document 1 discloses a (meth) acrylic resin film as a polarizing film that can satisfy durability and display uniformity (unevenness), particularly under humidified conditions. A polarizing plate using is described.

JP 2009-122663 A

  Usually, an ultraviolet absorber is blended in the protective film in order to increase the durability (light resistance) of the polarizing plate. In the case where protective films are bonded to both sides of a polarizer, it is common to add an ultraviolet absorber to the protective films on both sides.

  However, when a protective film containing an ultraviolet absorber is produced by the melt extrusion method, it slightly adheres to the surface of the protective film from which the particles of the ultraviolet absorber that are evaporated and heated again and solidified again are obtained. When the melt extrusion equipment is operated for a long time, liquid deposits containing UV absorbers are generated on the T-die, etc., and when it drops, it adheres to the surface of the protective film or enters the protective film as a phase different from the resin. It became clear by the inventor's examination. Such a problem becomes particularly remarkable when a (meth) acrylic resin is used for the protective film. This is because the (meth) acrylic resin film has a high transmittance from the visible region to the ultraviolet region, and therefore it is necessary to relatively increase the content of the ultraviolet absorber.

  The foreign substance derived from the above ultraviolet absorber can of course be a problem per se. However, when a protective film having a foreign substance is used as a protective film disposed on the liquid crystal cell side, the crossed Nicols formed on the liquid crystal panel Since foreign matter is contained therein, there is a possibility that the visibility may be lowered, for example, light leakage may occur in black display. Especially when it is used for a high-resolution liquid crystal panel whose number of pixels (horizontal x vertical) exceeds 2000 x 1000 in a large liquid crystal monitor or liquid crystal TV exceeding 40 inch size, even a small amount of foreign matter is recognized. This problem becomes prominent. In addition, in small tablet terminals and mobile terminals that are less than 10 inches, the screen size is small and the user concentrates on one point to view the screen, so that foreign objects tend to be recognized more easily than large display devices. As the resolution of these small liquid crystal panels is increased, the deterioration of visibility due to foreign matters becomes more remarkable.

  An object of the present invention is a polarizing plate in which a (meth) acrylic resin film is bonded to both sides of a polarizer, and has sufficient durability (light resistance), but contains foreign substances derived from an ultraviolet absorber. An object of the present invention is to provide a polarizing plate that does not have the risk of liquid crystal and a liquid crystal panel using the same.

The present invention provides the following polarizing plate and liquid crystal panel.
[1] A polarizer, a first (meth) acrylic resin film laminated on one surface of the polarizer, and a second (meth) acrylic resin film laminated on the other surface of the polarizer,
The first (meth) acrylic resin film contains an ultraviolet absorber and has a transmittance of 20% or less over the entire wavelength range of 190 to 380 nm,
Said 2nd (meth) acrylic-type resin film is a polarizing plate whose content of a ultraviolet absorber is 1 weight% or less.

  [2] The polarizing plate according to [1], wherein the second (meth) acrylic resin film has a transmittance of 20% or more in a wavelength range of 260 to 320 nm.

  [3] The first and second (meth) acrylic resin films are laminated on the polarizer via an adhesive layer formed from an ultraviolet curable adhesive, according to [1] or [2]. Polarizing plate.

  [4] The polarizing plate according to any one of [1] to [3], wherein a maximum value of transmittance in a wavelength region of 260 to 380 nm is 3% or less.

  [5] The polarizing plate according to any one of [1] to [4], further including an adhesive layer laminated on an outer surface of the second (meth) acrylic resin film.

  [6] The polarizing plate according to any one of [1] to [5], further including a coating layer laminated on an outer surface of the first (meth) acrylic resin film.

  [7] A liquid crystal panel comprising a liquid crystal cell and the polarizing plate according to any one of [1] to [6] disposed on at least one surface thereof.

  [8] The liquid crystal panel according to [7], wherein the polarizing plate is disposed such that the second (meth) acrylic resin film is on the liquid crystal cell side.

  [9] The liquid crystal panel according to [7] or [8], wherein the liquid crystal cell is an IPS mode liquid crystal cell.

  According to the present invention, a polarizing plate in which a (meth) acrylic resin film is bonded to both sides of a polarizer, has sufficient durability (light resistance), and reduces foreign substances derived from an ultraviolet absorber. A polarizing plate can be provided. This polarizing plate can be suitably applied to a liquid crystal panel.

It is a schematic sectional drawing which shows an example of the laminated constitution of the polarizing plate which concerns on this invention. It is a schematic sectional drawing which shows an example of the laminated constitution of the liquid crystal panel which concerns on this invention. It is a figure which shows the transmittance | permeability in a 190-380 nm wavelength range of the 1st (meth) acrylic-type resin film produced in Example 1. FIG. It is a figure which shows the transmittance | permeability in the wavelength range of 190-380 nm of the 2nd (meth) acrylic-type resin film produced in Example 1. FIG. It is a figure which shows the transmittance | permeability in a 190-380 nm wavelength range of the (meth) acrylic-type resin film produced in the comparative example 2. FIG. It is a figure which shows the transmittance | permeability in a 190-380 nm wavelength range of the 1st (meth) acrylic-type resin film produced in Example 4. FIG. It is a figure which shows the transmittance | permeability in a 190-380 nm wavelength range of the 2nd (meth) acrylic-type resin film produced in Example 4. FIG.

The polarizing plate according to the present invention will be described in detail below with reference to embodiments.
<Polarizing plate>
FIG. 1 is a schematic cross-sectional view showing an example of a layer configuration of a polarizing plate according to the present invention. As shown in FIG. 1, the polarizing plate of the present invention includes a polarizer 10; a first (meth) acrylic resin film 21 laminated on one surface of the polarizer 10; A second (meth) acrylic resin film 22 to be laminated is included. Usually, the 1st and 2nd (meth) acrylic-type resin films 21 and 22 are bonded and laminated | stacked on the polarizer 10 through the 1st adhesive bond layer 15 and the 2nd adhesive bond layer 25, respectively. As shown in FIG. 1, the polarizing plate of the present invention can further include an adhesive layer 30 laminated on the outer surface of the second (meth) acrylic resin film 22. In the present specification, “(meth) acryl” means at least one selected from the group consisting of acryl and methacryl. The same applies to “(meth) acrylate” and “(meth) acryloyl”.

(1) Polarizer A polarizer (also referred to as a polarizing film) 10 absorbs linearly polarized light having a vibration plane parallel to the optical axis and transmits linearly polarized light having a vibration plane orthogonal to the optical axis. For example, it may be a polyvinyl alcohol-based resin film that is uniaxially stretched and has a dichroic dye adsorbed and oriented. As the dichroic dye, iodine or a dichroic organic dye is used. The polyvinyl alcohol-based resin constituting the polarizer 10 includes polyvinyl alcohol, which is a saponified product of polyvinyl acetate, and a copolymer of vinyl acetate and other monomers copolymerizable therewith (for example, ethylene and unsaturated carboxylic acid). It may be a vinyl alcohol copolymer which is a saponified product. The thickness of the polarizer 10 is usually about 5 to 40 μm.

  The polarizer 10 includes a step of uniaxially stretching a polyvinyl alcohol-based resin film, a step of dyeing the polyvinyl alcohol-based resin film with a dichroic dye and adsorbing the dichroic dye, and polyvinyl alcohol on which the dichroic dye is adsorbed. The resin film can be manufactured through a step of treating with a boric acid aqueous solution and a step of washing with water after the treatment with the boric acid aqueous solution. The dichroic dye can be dyed by immersing the film in an aqueous solution containing the dichroic dye, and the treatment with the boric acid aqueous solution can be performed by immersing the film in the boric acid aqueous solution.

  Uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after dyeing the dichroic dye. When uniaxial stretching is performed after dyeing, this uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Moreover, you may uniaxially stretch in these several steps.

(2) 1st (meth) acrylic-type resin film The 1st (meth) acrylic-type resin film 21 is a protective film containing the ultraviolet absorber in order to provide durability (light resistance) to a polarizing plate, When applying a polarizing plate to a liquid crystal panel, the viewing side polarizing plate has a viewing side (the side opposite to the liquid crystal cell), and the backlight side polarizing plate has a backlight side (what is a liquid crystal cell? It is a protective film arranged on the opposite side.

[(Meth) acrylic resin]
The (meth) acrylic resin constituting the first (meth) acrylic resin film 21 is a polymer containing a structural unit derived from a (meth) acrylic monomer. The polymer is typically a polymer containing a methacrylic acid ester, and is preferably composed mainly of a methacrylic acid ester, that is, 50% by weight or more of a structural unit derived from the methacrylic acid ester based on the total amount of monomers. It is a polymer containing. The (meth) acrylic resin may be a methacrylic acid ester homopolymer, or based on the total amount of monomers, the structural unit derived from the methacrylic acid ester is 50% by weight or more and derived from other polymerizable monomers. A copolymer containing 50% by weight or less of a structural unit may be used.

  As the methacrylic acid ester that can constitute the (meth) acrylic resin, alkyl methacrylate can be used, and specific examples thereof include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, methacrylic acid. An alkyl methacrylate having 1 to 8 carbon atoms in the alkyl group, such as n-butyl acid, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate and 2-hydroxyethyl methacrylate; Including. The alkyl group preferably has 1 to 4 carbon atoms. In the (meth) acrylic resin, the methacrylic acid ester may be used alone or in combination of two or more.

  Among these, from the viewpoint of durability, the (meth) acrylic resin preferably includes a structural unit derived from methyl methacrylate, and more preferably includes 50% by weight or more based on the total amount of monomers.

  As said other polymerizable monomer which can comprise a (meth) acrylic-type resin, polymeric monomers other than acrylic ester, methacrylic ester, and acrylic ester can be mentioned, for example. As the acrylate ester, alkyl acrylate ester can be used. Specific examples thereof include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, acrylic It includes alkyl acrylates having 1 to 8 carbon atoms in the alkyl group such as t-butyl acid, 2-ethylhexyl acrylate, cyclohexyl acrylate, and 2-hydroxyethyl acrylate. The alkyl group preferably has 1 to 4 carbon atoms. In the (meth) acrylic resin, acrylic acid esters may be used alone or in combination of two or more.

  Examples of polymerizable monomers other than methacrylic acid esters and acrylic acid esters include, for example, monofunctional monomers having one polymerizable carbon-carbon double bond in the molecule, and polymerizable carbon-carbon double bonds in the molecule. Can be mentioned, but a monofunctional monomer is preferably used. Specific examples of the monofunctional monomer include styrene monomers such as styrene, α-methylstyrene, vinyltoluene, halogenated styrene and hydroxystyrene; vinyl cyanide such as acrylonitrile and methacrylonitrile; acrylic acid and methacrylic acid. Unsaturated acids such as maleic anhydride and itaconic anhydride; maleimides such as N-methylmaleimide, N-cyclohexylmaleimide and N-phenylmaleimide; allyl alcohols such as methallyl alcohol and allyl alcohol; vinyl acetate and vinyl chloride , Other monomers such as ethylene, propylene, 4-methyl-1-pentene, 2-hydroxymethyl-1-butene, methyl vinyl ketone, N-vinyl pyrrolidone, N-vinyl carbazole.

  Specific examples of the polyfunctional monomer include polyunsaturated carboxylic acid esters of polyhydric alcohols such as ethylene glycol dimethacrylate, butanediol dimethacrylate, trimethylolpropane triacrylate; allyl acrylate, allyl methacrylate, cinnamic acid. Alkenyl esters of unsaturated carboxylic acids such as allyl; polyalkenyl esters of polybasic acids such as diallyl phthalate, diallyl maleate, triallyl cyanurate, triallyl isocyanurate, aromatic polyalkenyl compounds such as divinylbenzene including. As the polymerizable monomer other than the methacrylic acid ester and the acrylic acid ester, only one kind may be used alone, or two or more kinds may be used in combination.

  The preferred monomer composition of the (meth) acrylic resin is 50 to 100% by weight of the methacrylic acid alkyl ester, 0 to 50% by weight of the acrylic acid alkyl ester based on the total monomer amount, and 0 to 50% of the other polymerizable monomers. 50% by weight, more preferably 50 to 99.9% by weight of methacrylic acid alkyl ester, 0.1 to 50% by weight of acrylic acid alkyl ester, and 0 to 49.9% by weight of other polymerizable monomers. is there.

  Further, the (meth) acrylic resin may have a ring structure in the polymer main chain because the durability of the film can be improved. The ring structure is preferably a heterocyclic structure such as a cyclic acid anhydride structure, a cyclic imide structure, or a lactone ring structure. Specific examples include cyclic acid anhydride structures such as glutaric anhydride structure and succinic anhydride structure, cyclic imide structures such as glutarimide structure and succinimide structure, and lactone ring structures such as butyrolactone and valerolactone. As the content of the ring structure in the main chain is increased, the glass transition temperature of the (meth) acrylic resin can be increased. The cyclic acid anhydride structure or cyclic imide structure is introduced by copolymerizing monomers having a cyclic structure such as maleic anhydride or maleimide, and the cyclic acid anhydride structure is introduced by dehydration / demethanol condensation reaction after polymerization. It can be introduced by a method, a method of reacting an amino compound and introducing a cyclic imide structure. A resin having a lactone ring structure (polymer) is prepared by preparing a polymer having a hydroxyl group and an ester group in a polymer chain, and then heating the hydroxyl group and the ester group in the obtained polymer by heating. Accordingly, it can be obtained by a method in which a lactone ring structure is formed by cyclocondensation in the presence of a catalyst such as an organic phosphorus compound.

  Polymers having a hydroxyl group and an ester group in the polymer chain are, for example, methyl 2- (hydroxymethyl) acrylate, 2- (hydroxymethyl) ethyl acrylate, 2- (hydroxymethyl) isopropyl acrylate, 2- It can be obtained by using (meth) acrylic acid ester having a hydroxyl group and an ester group such as n-butyl (hydroxymethyl) acrylate and t-butyl 2- (hydroxymethyl) acrylate as a part of the monomer. it can. A more specific method for preparing a polymer having a lactone ring structure is described in, for example, JP-A-2007-254726.

  A (meth) acrylic resin can be prepared by radical polymerization of a monomer composition containing the monomer as described above. A monomer composition can contain a solvent and a polymerization initiator as needed.

[Other resins]
The first (meth) acrylic resin film 21 may contain a resin other than the (meth) acrylic resin described above. The content of the other resin is preferably 0 to 50% by weight, more preferably 0 to 25% by weight, and still more preferably 0 to 10% by weight. Examples of the resin include olefin polymers such as polyethylene, polypropylene, ethylene-propylene copolymer, and poly (4-methyl-1-pentene); halogen-containing polymers such as vinyl chloride and chlorinated vinyl resins; polystyrene Styrene-based polymers such as styrene-methyl methacrylate copolymer and styrene-acrylonitrile copolymer; polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; polyarylate composed of aromatic diol and aromatic dicarboxylic acid Biodegradable polyesters such as polylactic acid and polybutylene succinate; polycarbonates; polyamides such as nylon 6, nylon 66 and nylon 610; polyacetals; polyphenylene oxides; Nsurufido; polyether ether ketone; polyether nitrile; polysulfone; polyether sulfone; can be a polyamide-imide and the like; polyoxyethylene Penji Ren.

[Ultraviolet absorber]
The ultraviolet absorber contained in the first (meth) acrylic resin film 21 can be an ultraviolet absorber having an absorption maximum at a wavelength of about 200 to 400 nm, and the type thereof is not particularly limited. For example, triazine And UV-based UV absorbers, benzophenone-based UV absorbers, benzotriazole-based UV absorbers, benzoate-based UV absorbers, and cyanoacrylate-based UV absorbers.

(Triazine UV absorber)
The triazine-based ultraviolet absorber has the following general formula (i):
Q ¹ -Q ² -OH (i)
It is represented by In the formula, Q ¹ represents a 1,3,5-triazine ring, and Q ² represents an aromatic ring.

  As a triazine type ultraviolet absorber represented by the general formula (i), for example, the following general formula (i-A):

There is a compound represented by:
In the formula, R ² , R ^{2 ′} , R ^{2 ″} , R ¹¹ , R ^{11 ′} and R ^{11 ″} are R ² , R ^{2 ′} , R ^{2 ″} in the general formula (i-B) described later. , R ¹¹ , R ^{11 ′} and R ^{11 ″} represent the same functional group, and R ^{18 ′} and R ^{18 ″} each independently represent a hydrogen atom, a hydroxyl group or an alkoxy group (—OR ¹ ). .

  Among the triazine-based ultraviolet absorbers represented by the general formula (i-A), the triazine-based ultraviolet absorber preferably used is the following general formula (i-B):

It is a compound represented by these.
In the formula, R ¹ is an alkyl group having 1 to 18 carbon atoms; a cycloalkyl group having 5 to 12 carbon atoms; an alkenyl group having 3 to 18 carbon atoms; a phenyl group; a phenyl group, a hydroxy group, and 1 carbon atom. to 18 alkoxy groups, cycloalkoxy group having a carbon number of 5-12, an alkenyloxy group having 3 to 18 carbon atoms, a halogen ^{atom, -COOH, -COOR 4, -O-} CO-R 5, -O-CO ^{-O-R 6, -CO-NH} 2, -CO-NHR 7, -CO-N (R 7) (R 8), CN, NH 2, NHR 7, -N (R 7) (R 8), -NH-CO-R ^5, a phenoxy group, a phenoxy group substituted with an alkyl group having 1 to 18 carbon atoms, phenyl - alkoxy group having 1 to 4 carbon atoms, bicycloalkyl cycloalkoxy group having 6 to 15 carbon atoms, Bicycloalkyl having 6 to 15 carbon atoms An alkyl group having 1 to 18 carbon atoms substituted with a ruxoxy group, a bicycloalkenylalkoxy group having 6 to 15 carbon atoms, or a tricycloalkoxy group having 6 to 15 carbon atoms; hydroxy group, 1 to 4 carbon atoms An alkyl group, an alkenyl group having 2 to 6 carbon atoms, or a cycloalkyl group having 5 to 12 carbon atoms substituted with —O—CO—R ⁵ ; a glycidyl group; —CO—R ⁹ or —SO ₂ —R or represents ^10; or R ¹ is one or more interrupted and / or hydroxy groups with an oxygen atom, a phenoxy group or an alkylphenoxy-substituted alkyl group having a carbon number of 3 to 50 under the carbon atoms from 7 to 18 Or R ¹ is —A; —CH ₂ —CH (XA) —CH ₂ —O—R ¹² ; —CR ¹³ R ^{13 ′} — (CH ₂ ) _m —X—A; —CH ₂ —CH (OA) —R ¹⁴ ; —CH ₂ -CH (OH) -CH ₂ -XA;

—CR ¹⁵ R ^{15 ′} —C (═CH ₂ ) —R ^{15 ″} ; —CR ¹³ R ^{13 ′} — (CH ₂ ) _m —CO—XA; —CR ¹³ R ^{13 ′} — (CH ₂ ) _m —CO—O—CR ¹⁵ R ^{15 ′} —C (═CH ₂ ) —R ^{15 ″} or —CO—O—CR ¹⁵ R ^{15 ′} —C (═CH ₂ ) —R ^{15 ″} (wherein A Represents —CO—CR ¹⁶ ═CH—R ¹⁷ ).

R ² , R ^{2 ′} and R ^{2 ″} are independently of each other an alkyl group having 6 to 18 carbon atoms; an alkenyl group having 2 to 6 carbon atoms; a phenyl group; a phenylalkyl having 7 to 11 carbon atoms. A group: COOR ⁴ ; CN; —NH—CO—R ⁵ ; a halogen atom; a trifluoromethyl group; —O—R ³ .

R ³ represents the definition given for R ¹ ; R ⁴ is an alkyl group having 1 to 18 carbon atoms; an alkenyl group having 3 to 18 carbon atoms; a phenyl group; phenyl having 7 to 11 carbon atoms An alkyl group; a cycloalkyl group having 5 to 12 carbon atoms; or R ⁴ is interrupted by one or more —O—, —NH—, —NR ⁷ —, —S— and OH, phenoxy group or Represents an alkyl group having 3 to 50 carbon atoms which may be substituted with an alkylphenoxy group having 7 to 18 carbon atoms; R ⁵ represents H; an alkyl group having 1 to 18 carbon atoms; 18 alkenyl groups; cycloalkyl groups having 5 to 12 carbon atoms; phenyl groups; phenylalkyl groups having 7 to 11 carbon atoms; bicycloalkyl groups having 6 to 15 carbon atoms; bicycloalkenyl groups having 6 to 15 carbon atoms Group; carbon atom R ⁶ is H; an alkyl group having 1 to 18 carbon atoms; an alkenyl group having 3 to 18 carbon atoms; a phenyl group; a phenylalkyl group having 7 to 11 carbon atoms. Represents a cycloalkyl group having 5 to 12 carbon atoms; R ⁷ and R ⁸ are each independently an alkyl group having 1 to 12 carbon atoms; an alkoxyalkyl group having 3 to 12 carbon atoms; Represents a dialkylaminoalkyl group having 16 carbon atoms; or represents a cycloalkyl group having 5 to 12 carbon atoms; or R ⁷ and R ⁸ together represent an alkylene group having 3 to 9 carbon atoms, 9 represents an oxaalkylene group having 9 carbon atoms or an azaalkylene group having 3 to ⁹ carbon atoms; R ⁹ is an alkyl group having 1 to 18 carbon atoms; an alkenyl group having 2 to 18 carbon atoms; a phenyl group; 12 A cycloalkyl group; a phenylalkyl group having 7 to 11 carbon atoms; a bicycloalkyl group having 6 to 15 carbon atoms; a bicycloalkylalkyl group having 6 to 15 carbon atoms, a bicycloalkenyl group having 6 to 15 carbon atoms; or It represents tricycloalkyl group having a carbon number of 6 to 15; R ¹⁰ is an alkyl group having 1 to 12 carbon atoms; represents an alkyl phenyl group having a carbon number of 7 to 14; phenyl; naphthyl R ^11, R ^{11 ′} and R ^{11 ″} are each independently H; an alkyl group having 1 to 18 carbon atoms; an alkenyl group having 3 to 6 carbon atoms; a phenyl group; a phenylalkyl group having 7 to 11 carbon atoms; atoms; an alkoxy group having 1 to 18 carbon atoms; R ¹² is an alkyl group having 1 to 18 carbon atoms; a phenyl group; an alkenyl group having 3 to 18 carbon atoms having 1 to 8 carbon atoms a Represents a phenyl group substituted 1-3 times with a kill group, an alkoxy group having 1 to 8 carbon atoms, an alkenoxy group having 3 to 8 carbon atoms, a halogen atom or a trifluoromethyl group; or 7 to 7 carbon atoms 11 phenylalkyl group; cycloalkyl group having 5 to 12 carbon atoms; tricycloalkyl group having 6 to 15 carbon atoms; bicycloalkyl group having 6 to 15 carbon atoms; bicycloalkylalkyl having 6 to 15 carbon atoms group; bicycloalkenyl group having a carbon number of 6 to 15; -CO-R ⁵ a represents; or R ¹² is one or more -O -, - NH -, - NR 7 -, - and interrupted by S- OH, optionally substituted phenoxy group or an alkylphenoxy group having a carbon number of 7 to 18, an alkyl group having a carbon number of 3 to 50; R ¹³ and R ^{13 'are} each independently H; charcoal A phenyl group; an alkyl group of atoms 18 R ¹⁴ is an alkyl group having 1 to 18 carbon atoms; a phenyl group; an alkyl group alkoxy having 3 to 12 carbon atoms phenyl - 1 to 4 carbon atoms R ¹⁵ , R ^{15 ′} and R ^{15 ″} each independently represent H or CH ₃ ; R ¹⁶ represents H; —CH ₂ —COO—R ⁴ ; alkyl having 1 to 4 carbon atoms It represents or CN; radical R ¹⁷ is H; represents or a phenyl group; an alkyl group having a carbon number of 1 to 17; -COOR ⁴ X is ^{-NH -; - NR 7 -;} - O -; - NH- (CH ₂ ) _p —NH—; or —O— (CH ₂ ) _q —NH—; and m represents a number from 0 to 19; n represents a number from 1 to 8; p represents a number from 0 to 4 It represents; q represents a number from 2 to 4; in the proviso formula ^{(i-B), R 1} , R 2, R 2 ', R 2'', R 11, R 11' and R ^{11 'low'} of Both one including two or more carbon atoms, it is.

  Specific examples of the triazine ultraviolet absorber include 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2 -Hydroxy-4-ethoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2 -Hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- 6- (2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-octyloxyphenyl) -1, , 5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-benzyloxy) Phenyl) -1,3,5-triazine and the like.

(Benzophenone UV absorber)
The benzophenone-based ultraviolet absorber has the following general formula (ii):

It is represented by In the formula, Q ³ and Q ⁴ each independently represent an aromatic ring. Y represents a substituent, and Z represents an oxygen atom, a sulfur atom or a nitrogen atom. YZ may be a hydrogen atom.

  Examples of benzophenone-based ultraviolet absorbers include 2,4-dihydroxy-benzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-n-octoxy-benzophenone, 2-hydroxy-4-dodecyloxy-benzophenone, 2-hydroxy-4-octadecyloxy-benzophenone, 2,2′-dihydroxy-4-methoxy-benzophenone, 2,2′-dihydroxy-4,4′-dimethoxy-benzophenone, 2,2 ′, 4,4 ′ -Tetrahydroxy-benzophenone and the like.

(Benztriazole UV absorber)
The benztriazole ultraviolet absorber is represented by the following general formula (iii):

It is represented by In the formula, R ²⁰ , R ²¹ , R ²² , R ²³ and R ²⁴ each independently represent a monovalent organic group, and at least one of R ²⁰ , R ²¹ and R ²² has a total carbon number of 10 to 20 It represents an unsubstituted branched or straight chain alkyl group.

  Examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-5-methylphenyl) benzotriazole and 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole. 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy- 3 ′, 5′-di-t-butylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6 ″ -tetrahydrophthalimide) Methyl) -5'-methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotria) 2-yl) phenol), 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5 '-Di-t-amylphenyl) -5-chlorobenzotriazole and the like.

(Benzoate UV absorber)
The benzoate-based ultraviolet absorber has the following general formula (iv):

It is represented by R ²⁵ and R ²⁶ in the formula each independently represent an alkyl group having 1 to 8 carbon atoms.
Examples of the benzoate ultraviolet absorber include 2,4-di-t-butylphenyl-3 ′, 5′-di-t-butyl-4′-hydroxybenzoate, 2,6-di-t-butylphenyl- 3 ', 5'-di-t-butyl-4'-hydroxybenzoate, n-hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate and n-octadecyl-3,5-di-t-butyl -4-hydroxybenzoate and the like.

(Cyanoacrylate UV absorber)
The cyanoacrylate ultraviolet absorber is represented by the following general formula (v):

It is represented by R ²⁷ in the formula is an organic group such as an alkyl group, an alkoxyalkyl group, an aralkyl group, a cycloalkyl group, an alkenyl group, and an aryl group.

  As an ultraviolet absorber, the ultraviolet absorber mentioned above may be used independently, respectively, and 2 or more types may be used together. Moreover, when using 2 or more types together, a mutually similar ultraviolet absorber may be sufficient and a different ultraviolet absorber may be sufficient.

  Commercially available products may be used as the UV absorber. For example, as a triazine UV absorber, “Kemisorb 102” manufactured by Chemipro Kasei Co., Ltd., “ADK STAB LA46”, “ADK STAB LAF70” manufactured by ADEKA Corporation, BASF “TINUVIN 460”, “TINUVIN 405”, “TINUVIN 400”, “TINUVIN 477” manufactured by Sanyo Chemical Co., Ltd., “CYASORB UV-1164” manufactured by Sun Chemical Co., Ltd. “LA31”, “Adeka Stub LA36”, “Sumisorb 200”, “Sumisorb 250”, “Sumisorb 300”, “Sumisorb 340”, “Sumisorb 350” manufactured by Sumika Chemtex Co., Ltd., “Kepro” misorb 74 ”,“ Kemisorb 79 ”,“ Kemisorb 279 ”,“ TINUVIN 99-2 ”,“ TINUVIN 900 ”,“ TINUVIN 928 ”manufactured by BASF, and the like.

  The weight average molecular weight of the ultraviolet absorber is preferably 500 to 1000, more preferably 550 to 800, from the viewpoint of suppressing transpiration during molding of the first (meth) acrylic resin film 21. If the weight average molecular weight is too small, it tends to evaporate during molding, and if the weight average molecular weight is too large, the compatibility with the resin constituting the first (meth) acrylic resin film 21 tends to decrease.

  The ultraviolet absorber preferably has a molar extinction coefficient at the absorption maximum wavelength of 10 L / mol · cm or more, and more preferably 15 L / mol · cm or more. When the molar absorption coefficient of the ultraviolet absorber is within the above range, the ultraviolet absorbing ability of the first (meth) acrylic resin film 21 can be increased, or the ultraviolet absorber can be contained while maintaining the excellent ultraviolet absorbing ability. The amount can be reduced.

  The molar extinction coefficient at 260 to 380 nm of the ultraviolet absorber is, for example, “Adekastab LA31” of the benzotriazole ultraviolet absorber, and has a maximum absorption wavelength at about 350 nm, and the molar absorption coefficient at the maximum absorption wavelength is 34821 L / mol · cm. The molar extinction coefficient varies depending on the chemical structure, and ultraviolet rays having a desired wavelength can be absorbed or transmitted by using an ultraviolet absorber alone or in combination.

In order to give sufficient light resistance, the content of the ultraviolet absorber is adjusted so that the transmittance in the entire wavelength range of 190 to 380 nm (entire region in the near ultraviolet region) is 20% or less, preferably 18%. It is adjusted to be as follows. Since the transmittance also depends on the thickness of the first (meth) acrylic resin film 21, the content of the ultraviolet absorber is determined in consideration of the employed thickness. The transmittance is the following formula:
Transmittance (%) = 100 × (transmitted light intensity I / incident light intensity I ₀ )
The transmittance at each wavelength can be measured by an ultraviolet-visible absorptiometer or the like.

  Although depending on the thickness of the first (meth) acrylic resin film 21, the content of the ultraviolet absorber in the film is usually 0.1% by weight or more, preferably 0.5% by weight or more. Usually, the content of the ultraviolet absorber is 5% by weight or less. In addition, content here is ultraviolet absorber content when the whole film amount is 100 weight%.

  Regarding the transmittance of ultraviolet rays as the whole polarizing plate, it is preferable to sufficiently reduce the transmittance in order to provide sufficient light resistance. Specifically, the maximum value of the transmittance in the wavelength region of 260 to 380 nm is preferably 3% or less, and more preferably 2% or less.

  The thickness of the first (meth) acrylic resin film 21 is, for example, about 5 to 200 μm, and preferably 10 to 150 μm, more preferably 15 to 100 μm, from the viewpoint of polarizing plate thinning and film strength and handleability. It is.

  The first (meth) acrylic resin film 21 can contain one or more additives other than the ultraviolet absorber. Examples of other additives include rubber particles, lubricants, dispersants, heat stabilizers, infrared absorbers, antistatic agents, and antioxidants.

  Mixing the rubber particles is advantageous in that the film-forming property of the (meth) acrylic resin, the impact resistance of the film, and the slipperiness of the film surface can be improved. Rubber particles are rubber elastic particles including a layer exhibiting rubber elasticity.

  The rubber particle may be a particle composed only of a layer exhibiting rubber elasticity, or may be a particle having a multilayer structure having another layer together with a layer exhibiting rubber elasticity. Examples of the rubber elastic body include an olefin elastic polymer, a diene elastic polymer, a styrene-diene elastic copolymer, an acrylic elastic polymer, and the like. Among these, acrylic elastic polymers are preferably used from the viewpoints of light resistance and transparency.

  The acrylic elastic polymer can be a polymer mainly composed of alkyl acrylate, that is, a polymer containing 50% by weight or more of a structural unit derived from alkyl acrylate based on the total amount of monomers. The acrylic elastic polymer may be a homopolymer of alkyl acrylate, and contains 50 wt% or more of structural units derived from alkyl acrylate and 50 wt% or less of structural units derived from other polymerizable monomers. A copolymer may also be used.

  As the alkyl acrylate constituting the acrylic elastic polymer, those having 4 to 8 carbon atoms in the alkyl group are usually used. Examples of the other polymerizable monomers include, for example, alkyl methacrylates such as methyl methacrylate and ethyl methacrylate; styrene monomers such as styrene and alkyl styrene; non-polymers such as acrylonitrile and methacrylonitrile. Monofunctional monomers such as saturated nitriles, as well as alkenyl esters of unsaturated carboxylic acids such as allyl (meth) acrylate and methallyl (meth) acrylate; dialkenyl esters of dibasic acids such as diallyl maleate; alkylene Polyfunctional monomers such as unsaturated carboxylic acid diesters of glycols such as glycol di (meth) acrylate.

  The rubber particles containing an acrylic elastic polymer are preferably multi-layered particles having an acrylic elastic polymer layer. Specifically, a two-layer structure having a hard polymer layer mainly composed of alkyl methacrylate outside the acrylic elastic polymer layer, or an alkyl methacrylate inside the acrylic elastic polymer layer. And a three-layer structure having a hard polymer layer mainly composed of.

  Examples of the monomer composition in the polymer mainly composed of alkyl methacrylate constituting the hard polymer layer formed outside or inside the acrylic elastic polymer layer are given as examples of (meth) acrylic resins. This is the same as the monomer composition example of a polymer mainly composed of alkyl methacrylate, and a monomer composition mainly composed of methyl methacrylate is preferably used. Such acrylic rubber elastic particles having a multilayer structure can be produced, for example, by the method described in Japanese Patent Publication No. 55-27576.

  From the viewpoint of film-forming properties of (meth) acrylic resin, impact resistance of the film, and slipperiness of the film surface, the rubber particles are included in the rubber elastic layer (acrylic elastic polymer layer) contained therein. The average particle size is preferably in the range of 10 to 350 nm. The average particle diameter is more preferably 30 nm or more, further 50 nm or more, and more preferably 300 nm or less, further 280 nm or less.

  The average particle size of the rubber particles up to the rubber elastic layer (acrylic elastic polymer layer) is measured as follows. That is, when such rubber particles are mixed with a (meth) acrylic resin to form a film and the cross section thereof is dyed with an aqueous solution of ruthenium oxide, only the rubber elastic body layer is colored and observed in a substantially circular shape. This (meth) acrylic resin is not dyed. Therefore, from the cross section of the film dyed in this way, a thin piece is prepared using a microtome or the like, and this is observed with an electron microscope. And after extracting 100 dye | stained rubber particles at random and calculating each particle diameter (diameter to a rubber elastic body layer), the number average value is made into the said average particle diameter. In order to measure by such a method, the obtained average particle diameter is a number average particle diameter.

  When the outermost layer is a hard polymer mainly composed of methyl methacrylate, and rubber particles in which a rubber elastic layer (acrylic elastic polymer layer) is encapsulated, the matrix (meta ) When mixed with an acrylic resin, the outermost layer of rubber particles is mixed with the base (meth) acrylic resin. Therefore, when the cross section is dyed with ruthenium oxide and observed with an electron microscope, the rubber particles are observed as particles in a state excluding the outermost layer. Specifically, when the inner layer is an acrylic elastic polymer and the outer layer is a rubber particle having a two-layer structure, which is a hard polymer mainly composed of methyl methacrylate, the acrylic elastic polymer portion of the inner layer Are dyed and observed as particles having a single layer structure. The innermost layer is a hard polymer mainly composed of methyl methacrylate, the intermediate layer is an acrylic elastic polymer, and the outermost layer is a rigid polymer mainly composed of methyl methacrylate. In the case of rubber particles, the central part of the innermost layer is not dyed, and only the acrylic elastic polymer part of the intermediate layer is dyed and observed as a two-layered particle.

  From the viewpoint of the film-forming property of the (meth) acrylic resin, the impact resistance of the film, and the slipperiness of the film surface, the rubber particles and the (meth) acrylic resin constituting the first (meth) acrylic resin film 21 Based on the total amount of these, it is preferable to mix | blend in the ratio of 3 weight% or more and 60 weight% or less, More preferably, it is 45 weight% or less, More preferably, it is 35 weight% or less. If the amount of the elastic rubber particles exceeds 60% by weight, the dimensional change of the film becomes large, and the heat resistance is lowered. On the other hand, when the amount of rubber elastic particles is less than 3% by weight, the heat resistance of the film is good, but the winding property during film formation is poor, and the productivity may be lowered. In the present invention, when the rubber elastic particle is a multi-layered particle having another layer together with the rubber elastic layer, the weight of the portion composed of the rubber elastic layer and the inner layer is determined. The weight of the elastic rubber particles. For example, when the acrylic rubber elastic particles having the above three-layer structure are used, the total weight of the acrylic rubber elastic polymer portion of the intermediate layer and the hard polymer portion mainly composed of methyl methacrylate of the innermost layer Is the weight of the rubber elastic particles. When the acrylic rubber elastic particles having the above three-layer structure are dissolved in acetone, the acrylic rubber elastic polymer portion of the intermediate layer and the hard polymer portion mainly composed of methyl methacrylate in the innermost layer are insoluble. Therefore, the total weight ratio of the intermediate layer and the innermost layer in the acrylic rubber elastic particles having a three-layer structure can be easily obtained.

  In the case where the first (meth) acrylic resin film 21 includes rubber particles, the (meth) acrylic resin composition containing the rubber particles used for producing the film includes a (meth) acrylic resin and rubber particles. Can be obtained by mixing them by melt kneading or the like, or by first producing rubber particles and polymerizing a monomer composition that is a raw material for the (meth) acrylic resin in the presence thereof.

(3) 2nd (meth) acrylic-type resin film The 2nd (meth) acrylic-type resin film 22 is a protective film laminated | stacked on the other surface of the polarizer 10, and when applying a polarizing plate to a liquid crystal panel, It is a protective film arranged on the liquid crystal cell side in both the polarizing plate on the viewing side and the polarizing plate on the backlight side.

  As described above, the polarizing plate of the present invention uses a film made of the same kind of resin for the protective films on both sides, but this causes the dimensional change to be vertically symmetric, so that the polarizing plate is warped, and consequently the liquid crystal. It is possible to prevent the panel from warping. Therefore, it is possible to prevent display defects caused by the warpage of the panel, for example, light leakage caused by the panel coming into contact with the peripheral edge (bezel). This is particularly effective in the IPS mode. Here, the film made of the same kind of resin may not be the same film as long as it is made of the same kind of resin. For example, the composition of the resin may be different, and the additive compounded in the film The amount and type of may vary.

  Unlike the first (meth) acrylic resin film 21, the second (meth) acrylic resin film 22 is a protective film having a high ultraviolet transmittance, and specifically, an ultraviolet absorber in the film. The content of is 1% by weight or less, preferably 0.5% by weight or less, more preferably 0.2% by weight or less, and particularly preferably contains no UV absorber.

  The content of the ultraviolet absorber in the second (meth) acrylic resin film 22 is relatively lower than that of the first (meth) acrylic resin film 21, or the second (meth) acrylic resin film 22 is The polarizing plate of the present invention containing no ultraviolet absorber can be advantageous in the following points, for example.

  [A] It is possible to suppress or prevent adhesion / mixing of foreign substances derived from the ultraviolet absorber as described above. That is, the foreign matter adheres and mixes in the T die when the (meth) acrylic resin film is heated and melted when the (meth) acrylic resin film is produced by the melt extrusion method, and this solidifies again into particles. It is presumed that the generated particles adhere to the film surface or the liquid substance containing the ultraviolet absorber hangs down and adheres to the film surface or mixes in the film. By suppressing as much as possible, such adhesion and mixing of foreign substances can be suppressed and prevented.

  In addition, even when an unstretched film of (meth) acrylic resin is produced by a melt extrusion method and subjected to a stretching treatment, adhesion / mixing of foreign matters as described above can be suppressed and prevented. The (meth) acrylic resin film may be subjected to stretching treatment in order to impart desired optical characteristics and mechanical characteristics after being produced by the melt extrusion method as described above. The stretching treatment can be performed by a conventionally known method, and examples thereof include uniaxial stretching and biaxial stretching. Examples of the stretching direction include a machine flow direction (MD) of an unstretched film, a direction orthogonal to the machine flow direction (TD), and a direction oblique to the machine flow direction (MD). Biaxial stretching may be simultaneous biaxial stretching that simultaneously stretches in two stretching directions, or sequential biaxial stretching that stretches in one direction and then stretches in the other direction.

  In particular, among the two (meth) acrylic resin films of the polarizing plate, the content of the ultraviolet absorber in the second (meth) acrylic resin film 22 disposed on the liquid crystal cell side when the liquid crystal panel is used. By suppressing, it can suppress that a foreign material is contained in the cross nicol formed in a liquid crystal panel. This can be effective in preventing a decrease in visibility such as light leakage in black display of the liquid crystal display device.

  [B] Since the ultraviolet absorber content of the second (meth) acrylic resin film 22 is low (preferably does not contain an ultraviolet absorber), the first and second (meth) acrylic resin films 21 and 22 are made ultraviolet rays. When bonding to the polarizer 10 using a curable adhesive, the adhesive can be easily cured without increasing the type of the photopolymerization initiator of the adhesive and the degree of curing can be increased. Thereby, the adhesiveness of the polarizer 10 and the (meth) acrylic-type resin film in the polarizing plate obtained, and the mechanical strength of a polarizing plate can be improved. On the other hand, since the first (meth) acrylic resin film 21 contains a sufficient amount of an ultraviolet absorber, sufficient light resistance is imparted to the polarizing plate.

  The second (meth) acrylic resin film 22 preferably has a high transmittance particularly in the wavelength region of 260 to 320 nm among ultraviolet rays, and specifically has a transmittance of 20% in the wavelength region of 260 to 320 nm. Preferably, it is preferably 30% or more, more preferably 40% or more. The wavelength range of 260 to 320 nm is a wavelength range to which an ultraviolet curable adhesive for bonding a polarizer and a protective film is generally sensitive. By increasing the transmittance in this wavelength range, UV curing is achieved. The curing rate and degree of curing of the adhesive can be increased, and the amount of photopolymerization initiator added in the adhesive can also be suppressed. In the present invention, that the transmittance in the wavelength region of 260 to 320 nm is 20% or more means that the transmittance is 20% or more in at least one place in the wavelength region of 260 to 320 nm.

When a polarizing plate is applied to a liquid crystal display device using an IPS mode liquid crystal cell, the second (meth) acrylic resin film 22 preferably has substantially no optical anisotropy. Specifically, the second (meth) acrylic resin film 22 preferably has an in-plane retardation value R ₀ at a wavelength of 590 nm of 10 nm or less, and more preferably 5 nm or less. The absolute value of the thickness direction retardation R _th at the wavelength 590nm is preferably 10nm or less, and more preferably 5nm or less.

The in-plane retardation value R ₀ and the thickness direction retardation value R _th are respectively represented by the following formulas:
_{R 0 = (n x -n y} ) × d
R _th = [(n _x + _ny ) / 2−n _z ] × d
Defined by n _x plane slow axis direction of the refractive index of the film, n _y is a refractive index in the in-plane fast axis direction (in-plane direction orthogonal slow axis direction and in-plane), n _z is the thickness direction refraction Rate, d is the thickness of the film.

  The (meth) acrylic resin constituting the second (meth) acrylic resin film 22, the type when containing an ultraviolet absorber, the thickness of the film, and other additives that can be blended in the film (for example, rubber particles) For the above, the above description about the first (meth) acrylic resin film 21 is cited. In particular, the (meth) acrylic resin is easy to be charged and easily adheres to environmental foreign matters, etc., so an antistatic agent (layer) is formed in the second (meth) acrylic resin film or on the second (meth) acrylic resin film. ) Is preferably added in an amount of 0.01 to 10 parts by weight. As with the foreign matter derived from the UV absorber, the foreign matter can be prevented from being contained in the crossed Nicols formed on the liquid crystal panel, and light leakage can occur in the black display of the liquid crystal display device. This can be effective in preventing a decrease in visibility.

  The 1st (meth) acrylic-type resin film 21 and the 2nd (meth) acrylic-type resin film 22 are the presence or absence of use of another additive, the kind and compounding quantity, the kind of ultraviolet absorber, (meth) acrylic-type resin. The thickness of the film and the film thickness may be the same, or any one or more may be different.

(4) First and second adhesive layers The first and second (meth) acrylic resin films 21, 22 and the polarizer 10 are usually bonded using an adhesive (the first and second adhesives in FIG. 1). 2 adhesive layers 15, 25). The adhesive forming the first and second adhesive layers 15 and 25 is preferably an ultraviolet curable adhesive, and more preferably an adhesive that cures in response to ultraviolet rays in a wavelength range of 260 to 320 nm. Therefore, the first and second adhesive layers 15 and 25 are preferably cured layers of the adhesive.

  The component that constitutes the ultraviolet curable adhesive and is cured by irradiation with ultraviolet rays (hereinafter also simply referred to as “curable component”) may be an epoxy compound, an oxetane compound, a (meth) acrylic compound, or the like. Among these, as the above-mentioned adhesive, an ultraviolet curable adhesive containing an epoxy compound that is cured by cationic polymerization as a curable component can be preferably used. The epoxy compound here means a compound having an average of 1 or more, preferably 2 or more epoxy groups in the molecule. Epoxy compounds may be used alone or in combination of two or more.

  An example of an epoxy compound that can be suitably used is a hydrogenated epoxy compound (aliphatic compound) obtained by reacting an alicyclic polyol obtained by hydrogenating an aromatic ring of an aromatic polyol with epichlorohydrin. A glycidyl ether of a polyol having a cyclic ring); an aliphatic epoxy compound such as an aliphatic polyhydric alcohol or a polyglycidyl ether of an alkylene oxide adduct thereof; one epoxy group bonded to the alicyclic ring in the molecule An alicyclic epoxy compound which is an epoxy compound having the above is included.

  Epoxy compounds can be easily obtained as commercial products. For example, “Epicoat” series sold by Japan Epoxy Resin Co., Ltd. and “Epicron” sold by DIC Corporation, respectively. Series, "Epototo" series sold by Toto Kasei Co., Ltd., "Adeka Resin" series sold by ADEKA Co., Ltd., "Denacol" series sold by Nagase ChemteX Corporation, and sold by Dow Chemical "Dow Epoxy" series, "Tepic" sold by Nissan Chemical Industries, Ltd.

  The alicyclic epoxy compounds can also be easily obtained as commercial products. For example, the “Celoxide” series and the “Cyclomer” series sold by Daicel Chemical Industries, Ltd. There are “Syracure” series sold by Chemical.

  The ultraviolet curable adhesive may contain a radically polymerizable (meth) acrylic compound as a curable component instead of, or together with, the epoxy compound that is cured by cationic polymerization. As the (meth) acrylic compound, a (meth) acrylic monomer having at least one (meth) acryloyl group in the molecule such as a (meth) acrylate monomer having at least one (meth) acryloyloxy group in the molecule A (meth) acrylamide monomer having at least one (meth) acryloyl group and an amide bond in the molecule; obtained by reacting two or more functional group-containing compounds, and at least two (meth) acryloyl in the molecule And (meth) acryloyl group-containing compounds such as (meth) acrylic oligomers having a group. The (meth) acryl oligomer is preferably a (meth) acrylate oligomer having at least two (meth) acryloyloxy groups in the molecule. Only one (meth) acrylic compound may be used alone, or two or more may be used in combination. The (meth) acrylic compound preferably contains a (meth) acrylamide monomer.

As a (meth) acrylamide monomer having at least one (meth) acryloyl group and an amide bond in the molecule, the following general formula (vi):
^{_{CH 2 = C (R 28)}} -CONH (2-i) - (L-O-R 29) i Formula (vi)
An N-substituted amide monomer represented by In the formula, R ²⁸ represents a hydrogen atom or a methyl group, L represents a methylene group or an ethylene group, R ²⁹ represents a hydrogen atom, a methyl group, or an ethyl group, and i represents 1 or 2.

  Specific examples of the N-substituted amide monomer represented by the general formula (vi) include, for example, N-hydroxyethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, N-methoxyethyl (meth) acrylamide, N-ethoxyethyl (meth) acrylamide, etc. are mentioned. These N-substituted amide monomers can be used singly or in combination of two or more.

  The N-substituted amide monomer represented by the general formula (vi) is preferable because it exhibits good adhesion even to a low moisture content polarizer and a protective film using a material having low moisture permeability. Among the exemplified monomers, N-hydroxyethyl (meth) acrylamide is more preferable because it exhibits particularly good adhesiveness.

  The radical polymerizable compound is a (meth) acrylic compound other than the N-substituted amide monomer represented by the general formula (vi), that is, other than the N-substituted amide monomer represented by the general formula (vi). N-substituted amide monomers, various monofunctional (meth) acrylates having aromatic rings and hydroxy groups, urethane (meth) acrylates, polyester (meth) acrylates, compounds having various (meth) acryloyl groups, and the like. May be. However, when considering the adhesiveness and water resistance of the adhesive layer, the ratio of the N-substituted amide monomer represented by the general formula (vi) to the total amount of the radical polymerizable compound is 50 to 99% by weight. It is preferable that it is 60 to 90% by weight.

  Examples of the N-substituted amide monomer other than the N-substituted amide monomer represented by the general formula (vi) include N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, and N, N. -Diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N-hexyl (meth) acrylamide, aminomethyl (meth) acrylamide, aminoethyl (meth) acrylamide, mercaaptmethyl (meta ) Acrylamide, mercaptoethyl (meth) acrylamide, N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine and the like.

  As the monofunctional (meth) acrylate having an aromatic ring and a hydroxy group, various monofunctional (meth) acrylates having an aromatic ring and a hydroxy group can be used. The hydroxy group may be present as a substituent of the aromatic ring, but is preferably present as a substituent of an organic group (hydrocarbon group, particularly an alkylene group) that bonds the aromatic ring and the (meth) acrylate.

  Examples of the monofunctional (meth) acrylate having an aromatic ring and a hydroxy group include a reaction product of a monofunctional epoxy compound having an aromatic ring and (meth) acrylic acid. Examples of the monofunctional epoxy compound having an aromatic ring include phenyl glycidyl ether, t-butylphenyl glycidyl ether, and phenyl polyethylene glycol glycidyl ether. Specific examples of the monofunctional (meth) acrylate having an aromatic ring and a hydroxy group include, for example, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3-t-butylphenoxypropyl (meth) acrylate. 2-hydroxy-3-phenyl polyethylene glycol propyl (meth) acrylate and the like.

  Moreover, as said urethane (meth) acrylate, the reaction material of the (meth) acrylate which has an isocyanate group, and the hydroxyl group of the one terminal of a diol compound, etc. are mentioned. Examples of the diol compound include polyurethane diol, polyester diol, polyether diol, polyalkylene glycol such as polyethylene glycol, polypropylene glycol, and the like.

  As a compound having a (meth) acryloyl group, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate And alkyl (meth) acrylates having 1 to 12 carbon atoms such as lauryl (meth) acrylate; (meth) acrylic acid alkoxyalkyl monomers such as (meth) acrylic acid methoxyethyl and (meth) acrylic acid ethoxyethyl; ) 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, (meta Acrylic acid Hydroxyl group-containing monomers such as 0-hydroxydecyl, 12-hydroxylauryl (meth) acrylate and (4-hydroxymethylcyclohexyl) -methyl acrylate; acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; acrylic acid Caprolactone adducts of: styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate and (meth) acryloyloxynaphthalene sulfonic acid Examples thereof include sulfonic acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate. Further, maleimide group-containing monomers such as maleimide, N-cyclohexylmaleimide and N-phenylmaleimide; aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate (Meth) acrylic acid alkylaminoalkyl monomers such as (meth) acrylic acid t-butylaminoethyl and 3- (3-pyridinyl) propyl (meth) acrylate; N- (meth) acryloyloxymethylene succinimide, N- ( Examples thereof include nitrogen-containing monomers including succinimide-based monomers such as (meth) acryloyl-6-oxyhexamethylene succinimide and N- (meth) acryloyl-8-oxyoctamethylene succinimide.

  (Meth) acryloyloxy group-containing compounds such as (meth) acrylate oligomers obtained by reacting two or more functional group-containing compounds and having at least two (meth) acryloyloxy groups in the molecule, that is, di (meth) As the acryloyloxy group-containing compound, a polyfunctional compound is preferable because the water resistance of the adhesive layer is improved. In consideration of the water resistance of the adhesive layer, the di (meth) acryloyloxy group-containing compound is more preferably hydrophobic. Hydrophobic di (meth) acryloyloxy group-containing compounds, particularly hydrophobic polyfunctional di (meth) acryloyloxy group-containing compounds include, for example, tricyclodecane dimethanol diacrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (Meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol Di (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate 1,9-nonanediol glycol di (meth) acrylate, glycerin di (meth) acrylate, ethylene oxide modified glycerin tri (meth) acrylate, ethylene oxide modified diglycerin tetra (meth) acrylate, (meth) acrylic acid 2- (2 -Vinyloxyethoxy) ethyl, bisphenol A-ethylene oxide adduct di (meth) acrylate, trimethylolpropane tri (meth) acrylate, hydroxypivalate neopentylglycol (meth) acrylic acid adduct, ethylene oxide modified trimethylolpropane tri (meth) ) Acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, Nuric acid ethylene oxide modified di (meth) acrylate, isocyanuric acid ethylene oxide modified tri (meth) acrylate, ε-caprolactone modified tris ((meth) acryloxyethyl) isocyanurate, 1,1-bis ((meth) acryloyloxymethyl) ethyl Examples include isocyanate, a polymer of 2-hydroxyethyl (meth) acrylate and 1,6-diisocyanate hexane, 9,9-bis [4- (2- (meth) acryloyloxyethoxy) phenyl] fluorene, and the like.

  The ratio of the di (meth) acryloyloxy group-containing compound to the total amount of the radical polymerizable compound is preferably 5 to 50% by weight, and more preferably 9 to 40% by weight. When this proportion is less than 5% by weight, a sufficient effect of improving water resistance may not be obtained, whereas when it exceeds 50% by weight, a sufficient effect of improving adhesiveness may not be obtained.

  In addition to the above, the ultraviolet curable adhesive may contain other functional group-containing compound as a radical polymerizable compound. Examples of other functional group-containing compounds include divinylbenzene and N, N′-methylenebisacrylamide.

  The ultraviolet curable adhesive may contain an oxetane compound together with or in place of the epoxy compound and / or the (meth) acrylic compound. Oxetane compounds can also be easily obtained as commercial products. For example, “Aron Oxetane” series sold by Toagosei Co., Ltd. and “ETERNCOLL” sold by Ube Industries, Ltd. There is a series etc.

  When the ultraviolet curable adhesive is contained as a curable component that is cured by cationic polymerization such as an epoxy compound, it preferably contains a photocationic polymerization initiator. Examples of the photocationic polymerization initiator include aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic sulfonium salts; iron-allene complexes. Further, when the ultraviolet curable adhesive contains a radical polymerizable curable component such as a (meth) acrylic compound, it is preferable to contain a photo radical polymerization initiator. Examples of the photo radical polymerization initiator include hydrogen abstraction type or cleavage type, for example, acetophenone initiator, benzophenone initiator, benzoin ether initiator, thioxanthone initiator, xanthone, fluorenone, camphorquinone, Examples thereof include benzaldehyde and anthraquinone. These initiators may contain two or more different photocationic polymerization initiators or photoradical initiators as necessary, or a photocationic polymerization initiator and a photoradical initiator may be used in combination. The wavelength range to which the photopolymerization initiator is sensitive is often 260 to 380 nm, and in particular, there are many having a peak near 320 nm.

  Cationic polymerization initiators can also be easily obtained on the market, for example, under the trade name, “Kayarad” series sold by Nippon Kayaku Co., Ltd., and sold by Union Carbide, Inc. Photo acid generators “CPI” series sold by SyraCure ”series, San Apro Co., Ltd. Photoacid generators“ TAZ ”,“ BBI ”and“ DTS ”sold by Midori Chemical Co., Ltd., from ADEKA Co., Ltd. There are “Adekaoptomer” series sold and “RHODORSIL” series sold by Rhodia.

  UV curable adhesives, if necessary, cationic polymerization accelerators such as polyols, photosensitizers, ion trapping agents, antioxidants, chain transfer agents, tackifiers, thermoplastic resins, fillers, flow It can contain additives such as a regulator, a plasticizer, an antifoaming agent, an antistatic agent, a leveling agent, and a solvent.

  The thicknesses of the first and second adhesive layers 15 and 25 are each independently, for example, about 0.01 to 10 μm, preferably about 0.01 to 5 μm, and more preferably 4 μm or less (for example, 3 μm or less). It is.

  An ultraviolet curable adhesive is applied to the bonding surface of the polarizer 10 or the bonding surfaces of the first and second (meth) acrylic resin films 21 and 22, and the applied ultraviolet curable adhesive layer is applied. After the films are stacked, a polarizing plate can be obtained by curing the adhesive layer by irradiating ultraviolet rays. In this bonding operation, after the polarizer 10 and the first (meth) acrylic resin film 21 are bonded first, the second (meth) acrylic resin film 22 may be bonded, or three sheets may be stacked at the same time. It may be bonded by irradiating with ultraviolet rays. It is preferable from a viewpoint of adhesive hardening that an ultraviolet-ray is irradiated 1 time or more from the 2nd (meth) acrylic-type resin film 22 side. As the ultraviolet light source, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp, or the like can be used.

  Prior to the bonding, the first and second (meth) acrylic resin films 21 and 22 are bonded to the polarizer 10 and the first and second (meth) acrylic resin films 21 and 22 in the polarizer 10. At least one of the bonding surfaces may be subjected to corona discharge treatment, plasma irradiation treatment, electron beam irradiation treatment, or other surface activation treatment.

(5) Adhesive layer The polarizing plate of the present invention is applied to the outer surface of the second (meth) acrylic resin film 22 (the surface opposite to the polarizer 10), and the polarizing plate to another member such as a liquid crystal cell. The adhesive layer 30 for bonding can be provided. The pressure-sensitive adhesive used for the pressure-sensitive adhesive layer 30 is, for example, a (meth) acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, a polyamide-based pressure-sensitive adhesive, a polyether-based pressure-sensitive adhesive, or a fluorine-based pressure-sensitive adhesive. In particular, a (meth) acrylic adhesive is preferably used from the viewpoints of transparency, adhesive strength, reliability, reworkability, and the like.

  The pressure-sensitive adhesive layer 30 can be provided by a method in which a pressure-sensitive adhesive is used, for example, in the form of an organic solvent solution, which is coated on the second (meth) acrylic resin film 22 and dried. Can be provided also by a method of transferring the sheet-like adhesive formed on the plastic film (referred to as a separate film) to the second (meth) acrylic resin film 22. In any method, it is preferable to attach a separate film on the outer surface of the pressure-sensitive adhesive layer 30 after being laminated on the second (meth) acrylic resin film 22 for surface protection. The thickness of the pressure-sensitive adhesive layer 30 is usually 2 to 40 μm.

  The separate film can be a film made of a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate, or the like. Among these, a stretched film of polyethylene terephthalate is preferable.

(6) Coating layer The polarizing plate of the present invention has an outer surface (on the side opposite to the polarizer 10) of the first (meth) acrylic resin film 21 in order to impart desired optical properties or other characteristics to the polarizing plate. The surface) can have a coating layer. Specific examples of the coating layer include a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, and an antifouling layer. The method for forming the surface treatment layer on the surface of the first (meth) acrylic resin film 21 is not particularly limited, and a known method can be used.

<LCD panel>
The liquid crystal panel according to the present invention includes a liquid crystal cell and the polarizing plate according to the present invention disposed on at least one surface thereof. An example of the layer structure of the liquid crystal panel according to the present invention is shown in FIG. The liquid crystal panel 2 shown in FIG. 2 uses the polarizing plate 1 shown in FIG. 1 as the polarizing plate disposed on both sides of the liquid crystal cell 40. As described above, the liquid crystal panel 2 is used only for one of the polarizing plates. The polarizing plate according to the invention may be used. Preferably, the polarizing plate according to the present invention is used at least as a polarizing plate on the viewing side.

  In the liquid crystal panel 2, the polarizing plate 1 is disposed such that the second (meth) acrylic resin film 22 is on the liquid crystal cell 40 side. Thereby, it can suppress that a foreign material contains in cross Nicol, maintaining the light resistance of the liquid crystal panel 2. FIG.

  The driving mode of the liquid crystal cell 40 may be any conventionally known mode such as an IPS mode, a VA (vertical alignment) mode, and a TN (twisted nematic) mode, but as described above, the IPS mode is preferable. . In the IPS mode, nematic liquid crystal that is homogeneously aligned in the absence of an electric field is driven by a horizontal electric field to display an image, and the advantage is that the viewing angle is wider than in other driving modes. . Although the color change (also referred to as oblique color shift) of the image depending on the viewing angle of the screen is relatively large, this point includes the second (meth) acrylic resin film 22 that has substantially no optical anisotropy. This can be improved by using a polarizing plate.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further more concretely, this invention is not limited by these examples. In addition, the transmittance | permeability of the (meth) acrylic-type resin film and the polarizing plate was measured in accordance with the following method.

[Measurement of transmittance of (meth) acrylic resin film]
The transmittance of the (meth) acrylic resin film in the ultraviolet region (190 to 380 nm) was measured using a spectrophotometer “UV-2450” manufactured by Shimadzu Corporation.

[Measurement of transmittance of polarizing plate]
The transmittance in the ultraviolet region (260 to 380 nm) of the polarizing plate was measured using an ultraviolet-visible spectrophotometer “V7100” manufactured by JASCO Corporation. The measurement is performed in the spectrum measurement mode with the Glan-Thompson polarizer removed, and after measuring the transmittance at an arbitrary sample angle, the sample is further rotated by 90 ° to measure the transmittance, and the average value is obtained. The transmittance of the polarizing plate was calculated.

<Example 1>
(1) Production of first (meth) acrylic resin film As (meth) acrylic resin, a copolymer of methyl methacrylate / methyl acrylate = 96% / 4% (weight ratio) was prepared. As rubber particles, the innermost layer is made of a hard polymer polymerized with methyl methacrylate using a small amount of allyl methacrylate, the intermediate layer is mainly composed of butyl acrylate, and further contains styrene and a small amount of allyl methacrylate. A three-layered elastic particle consisting of a hard polymer polymerized with a small amount of ethyl acrylate in methyl methacrylate, and consisting of a soft elastic material polymerized using A material having an average particle size up to a certain elastic body of 240 nm was prepared. In this rubber particle, the total weight of the innermost layer and the intermediate layer was 70% of the entire particle.

  The above (meth) acrylic resin 68.5% by weight, the above rubber particles 29.6% by weight, and ADEKA Corporation UV absorber “ADEKA STAB LA31” 1.9% by weight are mixed with a super mixer, and biaxial. It was melt-kneaded with an extruder to give pellets. The pellets were put into a 65 mmφ single screw extruder, extruded through a T die having a set temperature of 275 ° C., cooled by sandwiching both surfaces of two polishing roll films having mirror surfaces, and a first (meta) having a thickness of 40 μm. ) An acrylic resin film was obtained.

  In the melt extrusion molding described above, when the evaporated product near the T-type die was visually confirmed after 100 hours had passed since the extrusion of the resin, a large amount of evaporated product was observed, and thus the first (meta) obtained was obtained. There was a possibility that the transpiration material adhered to and mixed in the acrylic resin film. Moreover, the maximum transmittance (%) in the wavelength range of 190 to 380 nm of the obtained first (meth) acrylic resin film was 15.9%. FIG. 3 shows the transmittance in the wavelength range of 190 to 380 nm of the obtained first (meth) acrylic resin film.

(2) Production of second (meth) acrylic resin film A second (meth) acrylic resin film having a thickness of 40 μm was produced in the same manner as in the above (1) except that the ultraviolet absorber was not mixed. .

  When 100 hours passed from the start of resin extrusion, the transpiration product near the T-die was visually confirmed, and no accumulation of transpiration product was seen. Therefore, the obtained second (meth) acrylic resin film was It was judged that there was no fear that the transpiration was attached or mixed. Moreover, the maximum transmittance (%) in the wavelength range of 260 to 320 nm of the obtained second (meth) acrylic resin film was 78.7% at 316 nm. FIG. 4 shows the transmittance of the obtained first (meth) acrylic resin film in the wavelength range of 190 to 380 nm.

(3) Production of Polarizing Film A polyvinyl alcohol film having an average polymerization degree of about 2,400 and a saponification degree of 99.9 mol% or more and a thickness of 75 μm was immersed in pure water at 30 ° C. It was immersed in an aqueous solution having a weight ratio of water of 0.02 / 2/100 at 30 ° C. Then, it was immersed at 56.5 ° C. in an aqueous solution having a potassium iodide / boric acid / water weight ratio of 12/5/100. Subsequently, after washing with pure water at 8 ° C., it was dried at 65 ° C. to obtain a polarizing film in which iodine was adsorbed and oriented on polyvinyl alcohol. Stretching was performed mainly in the steps of iodine staining and boric acid treatment, the total stretching ratio was 5.3 times, and the thickness of the obtained polarizing film was 27 μm.

(4) Production of polarizing plate After corona treatment was applied to the bonding surface of the first (meth) acrylic resin film obtained in (1) above, polymerization was started on the corona-treated surface in a wavelength range of 260 to 320 nm. UV curing adhesive ("Aronix" manufactured by Toagosei Co., Ltd.) was applied. Similarly, after the corona treatment was performed on the bonding surface of the second (meth) acrylic resin film obtained in (2) above, the same UV curable adhesive was applied to the corona treatment surface. Next, the first (meth) acrylic resin film coated with an ultraviolet curable adhesive on one surface of the polarizing film obtained in (3) above, and the second coated with an ultraviolet curable adhesive on the other surface. The (meth) acrylic resin film was bonded using a bonding roll on the ultraviolet curable adhesive layer side. Then, the ultraviolet curing adhesive layer of both surfaces was hardened by irradiating an ultraviolet-ray from the 2nd (meth) acrylic-type resin film side, and the polarizing plate was obtained. The ultraviolet irradiation was performed so that the integrated light amount in the wavelength region of 260 to 320 nm was 200 mJ / cm ² . The maximum transmittance (%) in the wavelength region of 260 to 380 nm of the obtained polarizing plate was 2.3%. Moreover, even when the obtained polarizing plate was cut with scissors, it was confirmed that the (meth) acrylic resin film was not peeled off from the polarizing film, and the adhesive layers on both sides were sufficiently cured. It was.

<Example 2>
(1) Production of first (meth) acrylic resin film A first (meth) acrylic resin film was produced in the same manner as (1) of Example 1 except that the thickness was 80 μm. In the melt extrusion molding described above, when the evaporated product near the T-type die was visually confirmed after 100 hours had passed since the extrusion of the resin, a large amount of evaporated product was observed, and thus the first (meta) obtained was obtained. There was a possibility that the transpiration material adhered to and mixed in the acrylic resin film. Moreover, the maximum transmittance (%) in the wavelength range of 190 to 380 nm of the obtained first (meth) acrylic resin film was 3.5%.

(2) Production of second (meth) acrylic resin film A second (meth) acrylic resin film was produced in the same manner as (2) of Example 1 except that the thickness was 80 μm. When 100 hours passed from the start of resin extrusion, the transpiration product near the T-die was visually confirmed, and no accumulation of transpiration product was seen. Therefore, the obtained second (meth) acrylic resin film was It was judged that there was no fear that the transpiration was attached or mixed. Moreover, the maximum transmittance (%) in the wavelength region of 260 to 320 nm of the obtained second (meth) acrylic resin film was 75.1% at 316 nm.

(3) Production of Polarizing Plate A polarizing plate was produced in the same manner as (4) of Example 1 except that the first and second (meth) acrylic resin films produced in (1) and (2) were used. Was made. The maximum transmittance (%) in the wavelength region of 260 to 380 nm of the obtained polarizing plate was 0.3%. Moreover, even when the obtained polarizing plate was cut with scissors, it was confirmed that the (meth) acrylic resin film was not peeled off from the polarizing film, and the adhesive layers on both sides were sufficiently cured. It was.

<Example 3>
(1) Production of first (meth) acrylic resin film A first (meth) acrylic resin film was produced in the same manner as (1) of Example 1 except that the thickness was 80 μm. In the melt extrusion molding described above, when the evaporated product near the T-type die was visually confirmed after 100 hours had passed since the extrusion of the resin, a large amount of evaporated product was observed, and thus the first (meta) obtained was obtained. There was a possibility that the transpiration material adhered to and mixed in the acrylic resin film. Moreover, the maximum transmittance (%) in the wavelength range of 190 to 380 nm of the obtained first (meth) acrylic resin film was 3.5%.

(2) Production of second (meth) acrylic resin film The thickness was set to 80 μm, and 69.9% by weight of (meth) acrylic resin, 29.6% by weight of the rubber particles, and Co., Ltd. as a film forming material. A second (meth) acrylic resin film was produced in the same manner as (2) of Example 1 except that 0.5% by weight of an ultraviolet absorber “ADEKA STAB LA31” manufactured by ADEKA was used. When 100 hours passed from the start of resin extrusion, the transpiration product in the vicinity of the T-shaped die was visually confirmed. Since the accumulation of transpiration product was slight, the obtained second (meth) acrylic resin film It was judged that the risk of transpiration was adhering / mixing was extremely low. Moreover, the maximum transmittance (%) in the wavelength region of 260 to 320 nm of the obtained second (meth) acrylic resin film was 21.3% at 266 nm.

(3) Production of Polarizing Plate A polarizing plate was produced in the same manner as (4) of Example 1 except that the first and second (meth) acrylic resin films produced in (1) and (2) were used. Was made. The maximum transmittance (%) in the wavelength region of 260 to 380 nm of the obtained polarizing plate was 0.14%. Moreover, even when the obtained polarizing plate was cut with scissors, it was confirmed that the (meth) acrylic resin film was not peeled off from the polarizing film, and the adhesive layers on both sides were sufficiently cured. It was.

<Example 4>
(1) Production of first (meth) acrylic resin film A first (meth) acrylic resin film was produced in the same manner as (1) of Example 1 except that the thickness was 60 μm. In the melt extrusion molding described above, when the evaporated product near the T-type die was visually confirmed after 100 hours had passed since the extrusion of the resin, a large amount of evaporated product was observed, and thus the first (meta) obtained was obtained. There was a possibility that the transpiration material adhered to and mixed in the acrylic resin film. Moreover, the maximum transmittance (%) in the wavelength range of 190 to 380 nm of the obtained first (meth) acrylic resin film was 7.5%. FIG. 6 shows the transmittance of the obtained first (meth) acrylic resin film in the wavelength range of 190 to 380 nm.

(2) Production of second (meth) acrylic resin film First, a (meth) acrylic thermoplastic resin was produced by the following method. Methyl methacrylate (Wako Pure Chemical) was distilled at a reduced pressure of 0.01 MPa and 40 ° C. to remove the inhibitor. Next, in a 50 L tank, distilled methyl methacrylate / N-phenylmaleimide (Wako Pure Chemicals special grade) / cyclohexyl maleimide (Wako Pure Chemicals special grade) / metaxylene (Wako Pure Chemicals special grade, hereinafter mXy) = 48.6% / 4. A mixed monomer solution containing 8% / 6.6% / 40% (weight ratio) was prepared, and this was bubbled with nitrogen at a rate of 100 mL / min for 12 hours to remove dissolved oxygen. The mixed monomer solution was transferred to a 60 L reactor purged with nitrogen and the temperature was raised to 130 ° C. Next, at the same temperature, an initiator solution in which 0.12% by weight of a polymerization initiator [“Perbutyl O” from Nippon Oil & Fats Co., Ltd.] was dissolved in 12% by weight of mXy was added at a rate of 1 kg / hour. Polymerization was carried out and after 8 hours the reactor was cooled to 50 ° C.

Next, 500 L of methanol was added to a 1 m ³ reactor, and the polymerization solution was poured over 5 hours to precipitate the polymer. Thereafter, the mixture was further stirred for 2 hours and filtered under reduced pressure. 300 L of methanol was further poured into the methanol-containing polymer powder after filtration under reduced pressure and stirred again. Thereafter, filtration under reduced pressure was performed, and a methanol-containing powder was collected and dried in a 0.3 m ³ conical vacuum dryer under conditions of a degree of vacuum of 0.03 MPa and a temperature of 80 ° C. The dried powder was pelletized with a twin-screw extruder at 250 ° C. to obtain a pellet-like (meth) acrylic thermoplastic resin.

  Next, the pellet-like (meth) acrylic thermoplastic resin is put into a twin-screw extruder, melt-kneaded at 260 ° C., extruded through a T-shaped die having a set temperature of 255 ° C., and surface cooled by a mirror cooling roll. It was made to transfer and it was set as the unstretched film. Furthermore, this unstretched film was sequentially stretched using a melt stretching apparatus (MD stretch ratio: 1.8 times, TD stretch ratio: 2.5 times) to obtain a second (meth) acrylic resin film having a thickness of 40 μm. Obtained.

  In the above melt extrusion molding, when the transpiration product near the T-type die when 100 hours passed from the start of the extrusion of the resin was visually confirmed, no accumulation of the transpiration product was observed. It was judged that there was no fear that the transpiration material adhered to or mixed in the (meth) acrylic resin film. Moreover, the maximum transmittance (%) in the wavelength region of 260 to 320 nm of the obtained second (meth) acrylic resin film was 84.2% at 320 nm. The transmittance of the obtained second (meth) acrylic resin film in the wavelength range of 190 to 380 nm is shown in FIG.

(3) Production of Polarizing Plate A polarizing plate was produced in the same manner as (4) of Example 1 except that the first and second (meth) acrylic resin films produced in (1) and (2) were used. Was made. The maximum transmittance (%) in the wavelength range of 260 to 380 nm of the obtained polarizing plate was 1.0%. Moreover, even when the obtained polarizing plate was cut with scissors, it was confirmed that the (meth) acrylic resin film was not peeled off from the polarizing film, and the adhesive layers on both sides were sufficiently cured. It was.

<Comparative Example 1>
The first and second (meth) acrylic resin films were the same as (4) of Example 1 except that the (meth) acrylic resin film prepared in (1) of Example 2 was used. A polarizing plate was prepared. The maximum transmittance (%) in the wavelength region of 260 to 380 nm of the obtained polarizing plate was 0.1%. In the obtained polarizing plate, the adhesive layer was not sufficiently cured, and when the polarizing plate was cut with scissors, there was a problem that the (meth) acrylic resin film was peeled off from the polarizing film.

<Comparative Example 2>
(1) Production of (meth) acrylic resin film 8000 g of methyl methacrylate (MMA), 2000 g of 2- (hydroxymethyl) acrylic in a 30 L reaction kettle equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introduction pipe Methyl acid (MHMA) was charged with 10,000 g of toluene, heated to 105 ° C. while passing nitrogen therein, and refluxed, and then 10.0 g of tertiary amyl peroxyisononanoate (“Lupasol 570” manufactured by Atofina Yoshitomi) as an initiator. At the same time, a solution consisting of 20.0 g of initiator and 100 g of toluene was added dropwise over 4 hours while solution polymerization was performed under reflux (about 105 to 110 ° C.), followed by further aging over 4 hours. Went.

  To the obtained polymer solution, 10 g of stearyl phosphate / distearyl phosphate mixture (“Phoslex A-18” manufactured by Sakai Chemical Co., Ltd.) was added, and cyclization condensation reaction was performed under reflux (about 90 to 110 ° C.) for 5 hours. Then, the polymer solution obtained by the above cyclization condensation reaction was subjected to a barrel temperature of 260 ° C., a rotation speed of 100 rpm, a degree of vacuum of 13.3 to 400 hPa (10 to 300 mmHg), a rear vent number of 1, a forevent number of 4 Introduced into a single vent type screw twin screw extruder (φ = 29.75 mm, L / D = 30) at a processing rate of 2.0 kg / hour in terms of resin amount, the cyclocondensation reaction and desorption were carried out in the extruder. By performing volatilization and extruding, transparent lactone ring-containing acrylic resin pellets were obtained.

  The obtained lactone ring-containing acrylic resin pellet had a lactone cyclization rate of 97.0%, a mass average molecular weight of 147700, a melt flow rate of 11.0 g / 10 min, and a Tg (glass transition temperature) of 130 ° C. .

  The lactone ring-containing acrylic resin pellets obtained above are supplied to an extruder, and 1% by weight of UV absorber (TINUVIN 1577) manufactured by Ciba Specialty Chemicals is used for 100% by weight of the lactone ring-containing acrylic resin pellets. 1% by weight of UV absorber “ADEKA STAB LA31” manufactured by ADEKA Co., Ltd. is mixed, extruded from a T-die at a die temperature of 250 ° C. with a single-screw extruder, taken by water cooling with a cooling roll, and a film having a thickness of 120 μm is obtained. Obtained. Then, it is a biaxially stretched film having a thickness of 40 μm, which is subjected to 1.8-fold longitudinal stretching (heating temperature 140 ° C.) and then 2.4-fold transverse stretching (heating temperature 140 ° C.) with a sequential biaxial extruder. A lactone ring-containing (meth) acrylic resin film was obtained.

  In the above-described melt extrusion molding, when a transpiration product near the T-type die was visually observed after 100 hours from the start of resin extrusion, a large amount of the transpiration product was observed. There was a risk that the transpiration was adhering to and mixed in the resin film. Moreover, the maximum transmittance (%) in the wavelength range of 190 to 380 nm of the obtained (meth) acrylic resin film was 24.3% at 274 nm. FIG. 5 shows the transmittance of the obtained (meth) acrylic resin film in the wavelength range of 190 to 380 nm.

(2) Production of polarizing plate After the corona treatment was performed on the bonding surface of the (meth) acrylic resin film obtained in (1) above, an easy-adhesion layer having a thickness of 100 nm was formed on the corona-treated surface. The easy adhesion layer was prepared by adding 66.7 parts by weight of isopropyl alcohol to 100 parts by weight of silane coupling agent “APZ-6601” manufactured by Toray Dow Corning Silicone Co., Ltd. It was formed by applying with bar # 5 and evaporating volatile components.

  Subsequently, a polarizing plate was produced in the same manner as in (4) of Example 1 except that the (meth) acrylic resin film having an easy-adhesion layer was used as the first and second (meth) acrylic resin films. did. The maximum transmittance (%) in the wavelength region of 260 to 380 nm of the obtained polarizing plate was 1.5%.

  DESCRIPTION OF SYMBOLS 1 Polarizing plate, 2 Liquid crystal panel, 10 Polarizer, 21 1st (meth) acrylic-type resin film, 22 2nd (meth) acrylic-type resin film, 15 1st adhesive layer, 25 2nd adhesive layer, 30 Adhesion Agent layer, 40 liquid crystal cell.

Claims (9)

Including a polarizer, a first (meth) acrylic resin film laminated on one surface of the polarizer, and a second (meth) acrylic resin film laminated on the other surface of the polarizer,
The first (meth) acrylic resin film contains an ultraviolet absorber and has a transmittance of 20% or less over the entire wavelength range of 190 to 380 nm,
Said 2nd (meth) acrylic-type resin film is a polarizing plate whose content of a ultraviolet absorber is 1 weight% or less.   The polarizing plate according to claim 1, wherein the second (meth) acrylic resin film has a transmittance of 20% or more in a wavelength range of 260 to 320 nm.   The polarizing plate according to claim 1 or 2, wherein the first and second (meth) acrylic resin films are laminated on the polarizer via an adhesive layer formed of an ultraviolet curable adhesive.   The polarizing plate of any one of Claims 1-3 whose maximum value of the transmittance | permeability in a wavelength range of 260-380 nm is 3% or less.   The polarizing plate of any one of Claims 1-4 which further contains the adhesive layer laminated | stacked on the outer surface of a said 2nd (meth) acrylic-type resin film.   The polarizing plate according to claim 1, further comprising a coating layer laminated on an outer surface of the first (meth) acrylic resin film.   The liquid crystal panel containing a liquid crystal cell and the polarizing plate of any one of Claims 1-6 arrange | positioned at the at least one surface.   The liquid crystal panel according to claim 7, wherein the polarizing plate is disposed such that the second (meth) acrylic resin film is on the liquid crystal cell side.   The liquid crystal panel according to claim 7 or 8, wherein the liquid crystal cell is an IPS mode liquid crystal cell.

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