TWI656971B - Polarizing plate and liquid crystal display panel - Google Patents

Abstract

The present invention provides a polarizing plate comprising a polarizer, a first (meth) acrylic resin film laminated on one side of the polarizer, and a second (a) layer laminated on the other side of the polarizer. Base) an acrylic resin film; wherein the first (meth) acrylic resin film contains an ultraviolet absorber and has a transmittance of 20% or less in the entire region at a wavelength of 190 to 380 nm, and the second (meth) The content of the ultraviolet absorber of the acrylic resin film is 1% by weight or less; and a liquid crystal panel using the polarizing plate.

Description

Polarizer and LCD panel

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

A polarizing plate has been widely used as a polarized light supply element or a polarized light detection element in an image display device such as a liquid crystal display device. As a polarizing plate, it is a structure which attach | attaches a protective film to the single surface or both surfaces of a polarizer normally using an adhesive agent.

In Japanese Patent Application Laid-Open No. 2009-122663 (Patent Document 1), it is described that a polarizing plate capable of satisfying durability under humidified conditions and showing uniformity (mura) is used for a protective film bonded to both sides of a polarizer. A polarizing plate of a (meth) acrylic resin film.

Generally, an ultraviolet absorber is blended in the protective film in order to improve the durability (light resistance) of the polarizing plate. When a protective film is bonded to both sides of a polarizer, a protective film of an ultraviolet absorber is usually prepared on both sides.

However, it is clear from the review by the present inventors that if a protective film containing an ultraviolet absorbent is produced by a melt extrusion method, even if it is very small, Particles with ultraviolet absorbers that evaporate and solidify again when the molten resin is heated are attached to the surface of the resulting protective film, or due to the long-term operation of the extrusion melting device, liquid adhesion of ultraviolet absorbers to T-die and the like occurs. Objects adhere to the surface of the protective film due to dripping or are mixed into the protective film to become a phase different from the resin. Such a problem is particularly noticeable when a (meth) acrylic resin is used for the protective film. Since the (meth) acrylic resin film has a high transmittance from the visible light region to the ultraviolet light region, it is necessary to increase the content of the ultraviolet absorber.

Of course, the above-mentioned foreign matter derived from the ultraviolet absorber may be a problem in itself. However, when a protective film having a foreign matter is used as a protective film disposed on the liquid crystal cell side, it becomes a cross nicol formed on the liquid crystal panel. Foreign matter is contained, light leakage may occur during black display, and the visibility may be reduced. Especially when used in large LCD monitors and LCD TVs larger than 40 inches, and high-resolution LCD panels with a number of pixels (horizontal × vertical) exceeding 2000 × 1000, even foreign objects can be easily identified, and this problem becomes significant. . Moreover, in small tablet terminals and portable terminals less than 10 inches, the screen size is small. Because users concentrate on viewing the screen, compared with large display devices, foreign objects tend to be easily identified, and because of these small liquid crystals, The higher the resolution of the panel, the lower the visibility due to foreign objects.

An object of the present invention is to provide a polarizing plate in which a (meth) acrylic resin film is bonded to both sides of a polarizer, and has sufficient durability (light resistance), and at the same time, no foreign matter from an ultraviolet absorber is mixed in Yu's polarizers, and LCD panels using them.

The present invention provides the following polarizing plates and liquid crystal panels.

[1] A polarizing plate includes a polarizer, a first (meth) acrylic resin film laminated on one side of the polarizer, and a second (methyl) layer laminated on the other side of the polarizer. An acrylic resin film; wherein the first (meth) acrylic resin film contains an ultraviolet absorber and has a transmittance of 20% or less in the entire region of a wavelength of 190 to 380 nm; the second (meth) acrylic resin The content of the ultraviolet absorber in the resin film is 1% by weight or less.

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

[3] The polarizing plate according to [1] or [2], wherein the first and second (meth) acrylic resin films are laminated with an adhesive layer formed of an ultraviolet-curable adhesive through the adhesive layer. On the aforementioned polarizer.

[4] The polarizing plate according to any one of [1] to [3], wherein a maximum value of a 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 comprising 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 includes a liquid crystal cell and the polarizing plate according to any one of [1] to [6] arranged on a surface on at least one side thereof.

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

[9] The liquid crystal panel according to [8], wherein the liquid crystal cell is an IPS (horizontal To the electric field effect) mode.

According to the present invention, it is possible to provide a polarizing plate in which a (meth) acrylic resin film is bonded to both sides of a polarizer, and has sufficient durability (light resistance) and reduces foreign matter from ultraviolet absorbers. This polarizing plate can be suitably used for a liquid crystal panel.

1‧‧‧ polarizing plate

2‧‧‧ LCD panel

10‧‧‧ Polaroid

15‧‧‧The first adhesive layer

21‧‧‧The first (meth) acrylic resin film

22‧‧‧ 2nd (meth) acrylic resin film

25‧‧‧The second adhesive layer

30‧‧‧ Adhesive layer

40‧‧‧ LCD cell

FIG. 1 is a schematic cross-sectional view showing an example of a layer configuration of a polarizing plate of the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of a layer configuration of a liquid crystal panel of the present invention.

FIG. 3 is a graph showing a transmittance in a wavelength region of 190 to 380 nm of the first (meth) acrylic resin film produced in Example 1. FIG.

FIG. 4 is a graph showing a transmittance in a wavelength region of 190 to 380 nm of the second (meth) acrylic resin film produced in Example 1. FIG.

FIG. 5 is a graph showing a transmittance in a wavelength region of 190 to 380 nm of the (meth) acrylic resin film produced in Comparative Example 2. FIG.

FIG. 6 is a graph showing a transmittance in a wavelength region of 190 to 380 nm of the first (meth) acrylic resin film produced in Example 4. FIG.

FIG. 7 is a graph showing a transmittance in a wavelength region of 190 to 380 nm of the second (meth) acrylic resin film produced in Example 4. FIG.

Hereinafter, an embodiment is shown and the polarizing plate of this invention is demonstrated in detail.

<Polarizer>

FIG. 1 is a schematic cross-sectional view showing an example of a layer configuration of a polarizing plate of the present invention. The polarizing plate 1 according to the present invention of the polarizing plate 1 shown in FIG. 1 includes: a polarizing plate 10; a first (meth) acrylic resin film 21 laminated on one side of the polarizing plate 10; The second (meth) acrylic resin film 22 on the other side of the polarizer 10. The first and second (meth) acrylic resin films 21 and 22 are usually bonded and laminated on the polarizer 10 with the first adhesive layer 15 and the second adhesive layer 25 interposed therebetween, respectively. As shown in FIG. 1, the polarizing plate system of the present invention may further include an adhesive layer 30 laminated on the outer surface of the second (meth) acrylic resin film 22. In the present specification, the "(meth) acrylic acid" means at least one selected from the group consisting of acrylic acid and methacrylic acid. The same applies to "(meth) acrylate" or "(meth) acrylfluorenyl".

(1) Polarizer

A polarizer (also referred to as a polarizing film) 10 is an optical film having the property of absorbing linearly polarized light having a vibration plane parallel to the optical axis and penetrating linearly polarized light having a vibration plane having a vertical optical axis. Polyvinyl alcohol-based resin film in which a chromatic dye is adsorbed and aligned. As the dichroic dye system, iodine and a dichroic organic dye are used. The polyvinyl alcohol-based resin film constituting the polarizing plate 10 may be, in addition to polyvinyl alcohol which is a saponified product of polyvinyl acetate, vinyl acetate and other monomers (e.g., ethylene, unsaturated carboxylic acid) copolymerizable therewith. Acid, etc.) saponified copolymer of polyvinyl alcohol. The thickness of the polarizer 10 is usually about 5 to 40 μm.

The polarizer 10 can be made through a polyvinyl alcohol-based resin film. A step of shaft extension, a step of dyeing a polyvinyl alcohol-based resin film with a dichroic dye to adsorb the dichroic dye, a step of treating a polyvinyl alcohol-based resin film with the dichroic dye adsorbing an aqueous boric acid solution, and It is produced by a step of washing with a boric acid aqueous solution followed by washing with water. Dyeing of a dichroic dye can be performed by immersing a film in an aqueous solution containing a dichroic dye, and treatment of an aqueous boric acid solution can be performed by immersing the film in an aqueous solution of boric acid.

The uniaxial extension of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after dyeing the dichroic pigment. When the one-axis extension is performed after dyeing, the one-axis extension may be performed before or during the boric acid treatment. Furthermore, one-axis extension may be performed in the plural stages.

(2) 1st (meth) acrylic resin film

The first (meth) acrylic resin film 21 is a protective film containing an ultraviolet absorber in order to impart durability (light resistance) to the polarizing plate. When the polarizing plate is applied to a liquid crystal panel, the polarizing plate on the identification side is disposed on The protective film on the identification side (opposite to the liquid crystal cell), and the polarizing plate on the backlight side is a protective film disposed on the backlight side (opposite to the liquid crystal cell).

[(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 methacrylate, and it is more preferable that the methacrylate is the main body, that is, based on the total amount of monomers, it contains 50% by weight or more of the constituent units derived from the methacrylate. polymer. The (meth) acrylic resin may be a homopolymer of methacrylate, or may be based on the total monomer amount, and may contain at least 50% by weight of methyl-derived A copolymer of a structural unit of an acrylic ester and a structural unit derived from another polymerizable monomer in an amount of 50% by weight or less.

As the methacrylate that can constitute the (meth) acrylic resin, an alkyl methacrylate can be used, and specific examples thereof include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, and methyl Isopropyl acrylate, n-butyl methacrylate, isobutyl methacrylate, third butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, 2-hydroxy methacrylate The alkyl group of the ethyl ester has 1 to 8 carbon methacrylates. The carbon number of the alkyl group is preferably from 1 to 4. In the (meth) acrylic resin, a methacrylate may be used individually by 1 type, and may use 2 or more types together.

Among them, from the viewpoint of durability, the (meth) acrylic resin preferably contains a constituent unit derived from methyl methacrylate, and the constituent unit is more preferably contained in an amount of 50% by weight or more based on the total monomer amount.

Examples of the other polymerizable monomer that can constitute the (meth) acrylic resin include polymerizable monomers other than acrylate, methacrylate, and acrylate. As the acrylate, an alkyl acrylate can be used, and specific examples thereof include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, third butyl acrylate, and acrylic acid. The alkyl groups of 2-ethylhexyl acrylate, cyclohexyl acrylate, and 2-hydroxyethyl acrylate have 1 to 8 alkyl methacrylates. The carbon number of the alkyl group is preferably from 1 to 4. In the (meth) acrylic resin, acrylate may be used alone or in combination of two or more.

Polymerization other than methacrylate and acrylate Monofunctional monomers, such as a monofunctional monomer having one polymerizable carbon-carbon double bond in the molecule, and a polyfunctional monomer having at least two polymerizable carbon-carbon double bonds in the molecule, using a monofunctional group Monomers are ideal. Specific examples of the monofunctional monomer include: styrene-based monomers such as styrene, α-methylstyrene, vinyl toluene, halogenated styrene, and hydroxystyrene; cyanide such as acrylonitrile and methacrylonitrile Ethylene; unsaturated acids such as acrylic acid, methacrylic acid, maleic anhydride, and methylene succinic anhydride; such as N-methylmaleimide, N-cyclohexylmaleimide, N-benzene Maleimide of maleimide; allyl alcohol such as methallyl alcohol, allyl alcohol, etc .; such as vinyl acetate, vinyl chloride, ethylene, propylene, 4-methyl-1-pentyl Ene, 2-hydroxymethyl-1-butene, methyl vinyl ketone, N-vinyl pyrrolidone, other monomers of N-vinylcarbazole.

Further, specific examples of the polyfunctional monomer include polyunsaturated carboxylic acids of polyvalent alcohols such as ethylene glycol dimethacrylate, butanediol dimethacrylate, and trimethylolpropane triacrylate. Esters; such as allyl acrylate, allyl methacrylate, allyl cinnamate, unsaturated carboxylic acid allyl esters; diallyl phthalate, diallyl maleate, cyanuramide Triallyl acid, polyallyl esters of polyacids of triallyl isocyanurate, and aromatic polyene compounds such as divinylbenzene. The polymerizable monomers other than methacrylate and acrylate may be used individually by 1 type, and may use 2 or more types together.

The preferable composition of the (meth) acrylic resin is based on the total amount of monomers, 50 to 100% by weight of alkyl methacrylate, 0 to 50% by weight of alkyl acrylate, and other polymerizable monomers other than these. 0 to 50% by weight, more preferably 50 to 99.9% by weight of alkyl methacrylate, The alkyl acrylate is 0.1 to 50% by weight, and the polymerizable monomers other than these are 0 to 49.9% by weight.

In addition, the (meth) acrylic resin can improve the durability of the film, and can have a ring structure in the polymer main chain. The ring structure is preferably a heterocyclic structure such as a cyclic acid anhydride structure, a cyclic amidine structure, and a lactone ring structure. Specifically, cyclic anhydride structures such as glutaric anhydride structure and succinic anhydride structure, cyclic diimide structures such as glutarimide structure, succinimide structure, butyrolactone, valerolactone, etc. Lactone ring structure. The larger the content of the ring structure in the main chain, the higher the glass transition temperature of the (meth) acrylic resin. The cyclic acid anhydride structure and the cyclic fluorene imine structure can be introduced by copolymerizing a monomer having a cyclic structure such as maleic anhydride, maleimide, and the like, and dehydration / demethanol can be used after polymerization. A method of introducing a cyclic acid anhydride structure into a condensation reaction, a method of introducing a cyclic amidine structure by reacting an amine compound, and the like are introduced. A resin (polymer) having a lactone ring structure can be prepared from a polymer having a hydroxyl group and an ester group in a polymer chain, and the hydroxyl group and the ester group of the obtained polymer can be heated, for example, to an organic phosphorus compound as required. It is obtained by a method of cyclization and condensation under the presence of a catalyst to form a lactone ring structure.

For polymers having a hydroxyl group and an ester group in the polymer chain, for example, by using, for example, methyl 2- (hydroxymethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, and isopropyl 2- (hydroxymethyl) acrylate An ester, (butyl) 2- (hydroxymethyl) acrylate, and (meth) acrylic acid ester having a hydroxy group and an ester group as the third butyl 2- (hydroxymethyl) acrylate are obtained as part of the monomer. A more specific method for preparing a polymer having a lactone ring structure is described in, for example, Japanese Patent Application Laid-Open No. 2007-254726.

By radically polymerizing a monomer composition containing the monomers as described above, a (meth) acrylic resin can be prepared. The monomer composition may contain a solvent and a polymerization initiator as needed.

[Other resins]

The 1st (meth) acrylic-type resin film 21 may contain resins other than the said (meth) acrylic-type resin. The content ratio of the other resin is more preferably 0 to 50% by weight, more preferably 0 to 25% by weight, and even more preferably 0 to 10% by weight. The resin is, for example, an olefin-based polymer such as polyethylene, polypropylene, an ethylene-propylene copolymer, or poly (4-methyl-1-pentene); a halogen-containing polymer such as vinyl chloride or vinyl chloride resin; such as Polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer styrenic polymer; such as polyethylene terephthalate, polybutylene terephthalate, polynaphthalene Polyester of ethylene diformate; Polyarylate of aromatic diol and aromatic dicarboxylic acid; Biodegradable polyester of polylactic acid and polybutylene succinate; Polycarbonate; such as nylon 6 , Polyamide 66, nylon 610; polyacetal; polyphenylene ether; polyphenylene sulfide; polyether ether ketone; polyether nitrile; polyfluorene; polyether fluorene; polyoxyphenyl methyl ester; polyfluorene fluorene Imine and so on.

[Ultraviolet absorbent]

The ultraviolet absorbent contained in the first (meth) acrylic resin film 21 may be an ultraviolet absorbent having a maximum absorption at a wavelength of about 200 to 400 nm, and the type thereof is not particularly limited. For example, a triazine ultraviolet absorber , Benzophenone-based ultraviolet absorber, benzotriazole-based ultraviolet absorber, benzoate-based ultraviolet absorber, cyanoacrylate-based ultraviolet absorber, and the like.

(Triazine UV absorber)

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

Examples of the triazine-based ultraviolet absorber represented by the general formula (i) include the following general formula (iA): Shown compounds.

In the formula, R ² , R ^{2 ′} , R ^{2 ″} , R ¹¹ , R ^{11 ′,} and R ^{11 ″} represent the same as R ² , R ^{2 ′} , R ^{2 ″} , R ¹¹ , and R ¹¹ in the general formula (iB) described later. ^' And R ^{11 "are the} same functional group, and R ^18' and R ^18" represent a hydrogen atom, a hydroxyl group, or an alkoxy group (OR ¹ ) independently of each other.

Among the triazine-based ultraviolet absorbers represented by the general formula (iA), the triazine-based ultraviolet absorber that is more preferably used is the following general formula (iB): Shown compounds.

In the formula, R ¹ represents 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 hydroxyl group, and a carbon atom 1 Alkoxy to 18, cycloalkyl having 5 to 12 carbon atoms, alkenyloxy having 3 to 18 carbon atoms, halogen atom, -COOH, -COOR ⁴ , -O-CO-R ⁵ , -O- CO-OR 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 , phenoxy, phenoxy substituted by alkyl having 1 to 18 carbon atoms, phenyl-alkoxy having 1 to 4 carbon atoms, bicycloalkane having 6 to 15 carbon atoms Oxygen, bicycloalkylalkoxy having 6 to 15 carbon atoms or tricycloalkoxy having 6 to 15 carbon atoms and alkyl group having 1 to 18 carbon atoms; hydroxyl group, 1 to 4 carbon atoms Alkyl group, alkenyl group having 2 to 6 carbon atoms or -O-CO-R ⁵ substituted cycloalkyl group having 5 to 12 carbon atoms; epoxypropyl group; -CO-R ⁹ or -SO ₂ -R ¹⁰ represents; or R ¹ represents an alkyl group having 3 to 50 carbon atoms interrupted by one or more oxygen atoms and / or substituted with a hydroxyl group, a phenoxy group, or an alkylphenoxy group having 7 to 18 carbon atoms; Or R ¹ represents -A; -CH ₂ -C H (XA) -CH ₂ -OR ¹² ; -CR ¹³ R ^{13 '} -(CH ₂ ) _m -XA; -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" (where A represents -CO-CR ¹⁶ = CH-R ¹⁷ ).

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

R ³ represents the definition given to R ¹ ; R ⁴ represents an alkyl group having 1 to 18 carbon atoms; alkenyl group having 3 to 18 carbon atoms; phenyl group; phenyl alkyl group having 7 to 11 carbon atoms; carbon atom A cycloalkyl group of 5 to 12; or R ⁴ represents a group interrupted by one or more -O-, -NH-, NR ^7- , -S- and may be interrupted by OH, phenoxy, or 7 to 18 carbon atoms Alkylphenoxy substituted alkyl having 3 to 50 carbon atoms; R ⁵ represents H; alkyl having 1 to 18 carbon atoms; alkenyl having 2 to 18 carbon atoms; ring having 5 to 12 carbon atoms Alkyl; phenyl; phenylalkyl with 7 to 11 carbon atoms; bicycloalkyl with 6 to 15 carbon atoms; bicycloalkenyl with 6 to 15 carbon atoms; tricycloalkane with 6 to 15 carbon atoms R ⁶ represents H; alkyl group having 1 to 18 carbon atoms; alkenyl group having 3 to 18 carbon atoms; phenyl group; phenyl alkyl group having 7 to 11 carbon atoms; ring having 5 to 12 carbon atoms Alkyl; R ⁷ and R ⁸ each independently represent an alkyl group having 1 to 12 carbon atoms; an alkoxyalkyl group having 3 to 12 carbon atoms; a dialkylamino alkyl group having 4 to 16 carbon atoms; or represents a cycloalkyl group having 5 to 12 carbon atoms; or R ⁷ and R ⁸ together represent carbon atoms, an alkoxy become stretched 3 to 9 Carbon atoms, 3-9 oxygen or alkylene group having a carbon number aza 3-9 alkylene group; R ⁹ represents an alkyl group having 1 to 18 carbon atoms; an alkenyl group having a carbon number of 2 to 18; Benzene Cycloalkyl having 5 to 12 carbon atoms; Phenylalkyl having 7 to 11 carbon atoms; Bicycloalkyl having 6 to 15 carbon atoms; Bicycloalkylalkyl having 6 to 15 carbon atoms; Carbon Bicycloalkenyl with 6 to 15 atoms; or tricycloalkyl with 6 to 15 carbon atoms; R ¹⁰ represents an alkyl group with 1 to 12 carbon atoms; phenyl; naphthyl; or 7 to 14 carbon atoms Alkylphenyl; R ¹¹ , R ^{11 ′} and R ^{11 ″} each independently represent H; an alkyl group having 1 to 18 carbon atoms; an alkenyl group having 3 to 6 carbon atoms; a phenyl group; Phenylalkyl; halogen atom; alkoxy group having 1 to 18 carbon atoms; R ¹² represents alkyl group having 1 to 18 carbon atoms; alkenyl group having 3 to 18 carbon atoms; phenyl group; An alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, a halogen atom, or a phenyl group substituted 1 to 3 times with a trifluoromethyl group; or 7 to 6 carbon atoms 11 phenylalkyl; cycloalkyl having 5 to 12 carbon atoms; tricyclic alkyl having 6 to 15 carbon atoms Bicyclic alkyl group having a carbon number of 6 to 15; bicyclic carbon atoms, cycloalkylalkyl of 6 to 15; bicyclic carbon atoms, an alkenyl group having 6 to 15; -CO-R ^5; or R ¹² represents a The above -O-, -NH-, NR ^7- , -S- is interrupted and the alkyl group having 3 to 50 carbon atoms may be substituted by OH, phenoxy or alkylphenoxy group having 7 to 18 carbon atoms R ¹³ and R ^{13 ′} each independently represent H; an alkyl group having 1 to 18 carbon atoms; a phenyl group; R ¹⁴ represents an alkyl group having 1 to 18 carbon atoms; an alkoxyalkyl group having 3 to 12 carbon atoms Phenyl; phenyl-alkyl having 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 ; carbon Alkyl group having 1 to 4 atoms; or CN; R ¹⁷ represents H; -COOR ⁴ ; alkyl group having 1 to 17 carbon atoms; or phenyl group; X represents -NH-; -NR ^7- ; -O-; -NH- (CH ₂ ) _p -NH-; or -O- (CH ₂ ) _q -NH-; and m represents the number 0 to 19; n represents the number 0 to 8; p represents the number 0 to 4; q represents 2 To 4; however, in the general formula (iB), at least one of R ¹ , R ² , R ^{2 ′} , R ^{2 ″} , R ¹¹ , R ^{11 ′,} and R ^{11 ″} contains 2 or more carbon atoms.

Specific examples of the triazine-based 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) -1,3,5-triazine, 2,4-diphenyl-6 -(2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-benzyloxyphenyl) -1,3,5-triazine and so on.

(Benzophenone-based UV absorber)

The benzophenone-based ultraviolet absorber is represented by the following general formula (ii): As shown. 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 the benzophenone-based ultraviolet absorber include 2,4-dihydroxy-benzophenone, 2-hydroxy-4-methoxy-benzophenone, and 2-hydroxy 4-n-octyloxy-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'-tetrakis Hydroxy-benzophenone and the like.

(Benzotriazole UV absorber)

The benzotriazole-based ultraviolet absorber is represented by the following general formula (iii): As shown. 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 represents an unsubstituted branch having a total carbon number of 10 to 20 or Linear alkyl.

Examples of the benzotriazole-based ultraviolet absorber include 2- (2'-hydroxy-5-methylphenyl) benzotriazole and 2- (2'-hydroxy-3 ', 5'-secondary Butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-third butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'- Methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 '-(3 ”, 4”, 5 ”, 6” -tetrahydrophthalimidoiminomethyl) -5'-methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2'-hydroxy-3'-tertiary butyl -5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-di-third-pentylphenyl) -5-chlorobenzotriazole, etc. .

(Benzoate UV absorber)

The benzoate-based ultraviolet absorber is represented by the following general formula (iv): As shown. In the formula, R ²⁵ and R ²⁶ each independently represent an alkyl group having 1 to 8 carbon atoms.

Examples of the benzoate-based ultraviolet absorber include 2,4-di-tert-butylphenyl-3 ', 5'-di-tert-butyl-4'-hydroxybenzoate, and 2,6- Di-tert-butylphenyl-3 ', 5'-di-tert-butyl-4'-hydroxybenzoate, n-hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate Esters and n-octadecyl-3,5-di-tert-butyl-4-hydroxybenzoate.

(Cyanoacrylate UV absorber)

The cyanoacrylate-based ultraviolet absorber is represented by the following general formula (v): As shown. In the formula, R ²⁷ represents an organic group such as an alkoxyalkyl group, an aralkyl group, a cycloalkyl group, an alkenyl group, or an aromatic group.

As the ultraviolet absorbent, the above-mentioned ultraviolet absorbent may be used alone, or two or more kinds may be used in combination. Moreover, when two or more types are used in combination, they may be the same type of ultraviolet absorbent, or they may be different types of ultraviolet absorbent.

As the ultraviolet absorber, commercially available products can be used, and examples thereof include "Kemisorb 102" manufactured by CHEMIPRO Kasei Corporation, which is a triazine-based ultraviolet absorbent, "ADEKA STAB LA46", "ADEKA STAB LAF70", manufactured by ADEKA, and BASF Corporation. "TINUVIN 460", "TINUVIN 405", "TINUVIN 400", "TINUVIN 477", "CYASORB UV-1164" manufactured by SUNCHEMI Corporation; "ADEKA STAB LA31" manufactured by ADEKA Corporation as a benzotriazole UV absorber "," ADEKA STAB LA36 "by ADEKA," SUMISORB 200 "," SUMISORB 250 "," SUMISORB 300 "," SUMISORB 340 "," SUMISORB 350 "," SUMISORB 350 ", and" Kemisorb74 "manufactured by Chemipro "," Kemisorb79 "," Kemisorb279 "," TINUVIN 99-2 "made by BASF," TINUVIN 900 "," TINUVIN 928 ", etc.

The respective weight average molecular weights of the ultraviolet absorbers are preferably 500 to 1,000, and more preferably 550 to 800, from the viewpoint of suppressing evaporation during the molding of the first (meth) acrylic resin film 21. When the weight average molecular weight is too small, it is easy to evaporate during molding, and when the weight average molecular weight is too large, the compatibility with the resin constituting the first (meth) acrylic resin film 21 tends to be low.

The ultraviolet absorption agent has a molar absorption coefficient of 10 L / mol at its maximum absorption wavelength. cm is ideal, at 15L / mol. cm is more ideal. When the molar absorption coefficient of the ultraviolet absorber is in the above range, the ultraviolet absorption ability of the first (meth) acrylic resin film 21 can be improved, or a good ultraviolet absorption ability can be maintained, and the content of the ultraviolet absorber can be reduced. the amount.

The molar absorption coefficient of the ultraviolet absorber at 260 to 380 nm, for example, "ADEKA STAB LA31" manufactured by ADEKA Corporation, a benzotriazole-based ultraviolet absorbent, has a maximum absorption wavelength of about 350 nm, and the molar absorption coefficient of the maximum absorption wavelength It is 34621L / mol. cm. The Mohr absorption coefficient varies depending on the chemical structure. By using it alone or in combination with an ultraviolet absorbent, it can absorb or penetrate ultraviolet rays of a desired wavelength.

In order to provide sufficient light resistance, the content of the ultraviolet absorber is adjusted to 20% or less, and more preferably 18% or less, in the entire range of the wavelength of 190 to 380 nm (all the near ultraviolet range). Since the transmittance depends on the thickness of the first (meth) acrylic resin film 21, the content of the ultraviolet absorber is also determined in consideration of the thickness to be used. The transmittance is defined by the following formula: transmittance (%) = 100 × (intensity of transmitted light I / intensity of incident light I ₀ ). The transmittance of each wavelength can be determined by ultraviolet visible light absorption photometer, etc. Determination.

Although it varies with the thickness of the 1st (meth) acrylic-type resin film 21, content of the ultraviolet absorber in this film is 0.1 weight% or more normally, Preferably it is 0.5 weight% or more. The content of the ultraviolet absorber is usually 5% by weight or less. The content herein refers to the content of the ultraviolet absorber when the total amount of the film is 100% by weight.

Further, it is desirable that the transmittance of ultraviolet rays as the entire polarizing plate is sufficiently reduced in order to provide sufficient light resistance. Specifically, the maximum value of the transmittance in the wavelength region of 260 to 380 nm is 3% The following is ideal, and more preferably 2% or less.

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

The first (meth) acrylic resin film 21 may 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, antioxidants, and the like.

The blending of the rubber particles is advantageous in that the film forming property of the (meth) acrylic resin, the impact resistance of the film, and the smoothness of the film surface can be improved. The rubber particles are rubber elastomer particles including a layer exhibiting rubber elasticity.

The rubber particles may be particles composed of only a layer exhibiting rubber elasticity, or particles having a multilayer structure including a layer exhibiting rubber elasticity and other layers. Examples of the rubber elastomer include olefin-based elastic polymers, diene-based elastic polymers, styrene-diene-based elastic copolymers, and acrylic-based elastic polymers. Among them, it is preferable to use an acrylic elastic polymer from the viewpoint of light resistance and transparency.

The acrylic elastic polymer may be a polymer mainly composed of an alkyl acrylate, that is, based on the total amount of monomers, and containing 50% by weight or more of a constituent unit derived from an alkyl acrylate. The acrylic elastic polymer may be a homopolymer of an alkyl acrylate, or may be a structural unit containing 50% by weight or more of a methacrylate-derived structural unit and 50% by weight or less. Copolymer of constituent units from other polymerizable monomers.

As the alkyl acrylate constituting the acrylic elastic polymer, those having 4 to 8 carbon atoms in the alkyl group can be generally used. Examples of the other polymerizable monomers mentioned above include methyl methacrylate and alkyl methacrylate; styrene-based monomers such as styrene and alkylstyrene; acrylonitrile and methyl Monofunctional monomers such as unsaturated acrylonitrile based on acrylonitrile, and allyl esters of unsaturated carboxylic acids such as allyl (meth) acrylate, methallyl (meth) acrylate, etc. A polyfunctional monomer such as a diene ester of a dibasic acid of a diallyl butadiene acid; an unsaturated carboxylic acid diester of a diol such as an alkanediol di (meth) acrylate.

The rubber particles containing the acrylic elastic polymer are preferably particles having a multilayer structure having a layer of the acrylic elastic polymer. Specifically, for example, a two-layer structure having a hard polymer layer mainly composed of an alkyl methacrylate on the outside of the acrylic elastic polymer layer, or having A three-layer structure of a rigid polymer layer mainly composed of alkyl methacrylate.

Examples of the monomer composition of a polymer mainly composed of an alkyl methacrylate which is a hard polymer layer formed on the outer or inner side of the acrylic elastic polymer layer are examples of the (meth) acrylic resin Examples of the monomer composition of the polymer mainly composed of alkyl methacrylate are the same. In particular, it is preferable to use a monomer composition mainly composed of methyl methacrylate. The acrylic rubber elastomer particles having such a multilayer structure can be produced, for example, by the method described in Japanese Patent Publication No. 55-27576.

Film formation of rubber particles from (meth) acrylic resin From the viewpoints of properties, impact resistance of the film, and smoothness of the film surface, the average particle diameter of the rubber elastomer layer (layer of acrylic elastic polymer) included therein is preferably in a 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, and further 280 nm or less.

The average particle diameter of the rubber particles to the rubber elastomer layer (layer of the acrylic elastic polymer) was measured in the following manner. That is, when such rubber particles are mixed with a (meth) acrylic resin to make it into a thin film. When the cross section is dyed with an aqueous solution of ruthenium oxide, only the rubber elastomer layer is colored. The acrylic resin was not dyed. Therefore, from the cross section of the film dyed in this manner, a slice is prepared using a microtome or the like, and observed with an electron microscope. Then, 100 dyed rubber particles were randomly taken, each particle diameter (diameter of the rubber elastomer layer) was calculated, and the number average was used as the average particle diameter. Since it is measured by such a method, the said average particle diameter obtained is a number average particle diameter.

The outermost layer is a hard polymer mainly composed of methyl methacrylate. When rubber particles surrounded by a rubber elastomer layer (acrylic elastic polymer layer) are mixed, if they are mixed with a base methacrylic resin, the rubber The outermost layer of the particles is mixed with the parent methacrylic resin. Therefore, when the cross section was stained with ruthenium oxide and observed with an electron microscope, rubber particles were observed as particles in a state where the outermost layer was removed. Specifically, when the inner layer is an acrylic elastic polymer and the outer layer is a rubber particle having a two-layer structure of a hard polymer mainly composed of methyl methacrylate, the acrylic elastic polymer portion of the inner layer is dyed, and it is observed that Single-layered particles. and In addition, a rubber having a three-layer structure in which 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 particles, the inner part of the innermost particle was not dyed, and only the acrylic elastic polymer part of the middle layer was dyed, and particles with a two-layer structure were observed.

From the viewpoint of the film-forming properties of the methacrylic resin, the impact resistance of the film, and the smoothness of the film surface, based on the total amount of the methacrylic resin constituting the first (meth) acrylic resin film 21, The blended rubber particles are preferably in a ratio of 3% by weight to 60% by weight, more preferably 45% by weight or less, and even more preferably 35% by weight or less. When the rubber elastomer particles are more than 60% by weight, the dimensional change of the film becomes large, and the heat resistance thereof decreases. On the other hand, when the rubber elastomer particles are less than 3% by weight, the film has good heat resistance, but has poor winding properties and low productivity during film formation. In addition, in the present invention, when the particles having a multilayer structure having a layer exhibiting rubber elasticity and other layers are used as the rubber elastomer particles, the weight of the portion composed of the layer exhibiting rubber elasticity and the layer on the inside thereof is rubber. The weight of the elastomer particles. For example, when using the acrylic rubber elastomer particles having the three-layer structure described above, the total weight of the acrylic elastic polymer portion of the intermediate layer and the hard polymer portion mainly composed of the innermost methyl methacrylate is set to the rubber elastomer. The weight of the particles. When the acrylic rubber elastomer particles of the above three-layer structure are dissolved in acetone, the acrylic elastic polymer part of the intermediate layer and the hard polymer part mainly composed of the innermost methyl methacrylate remain because of the insoluble component, Therefore, the total weight ratio of the intermediate layer and the innermost layer of the acrylic rubber particles occupying a three-layer structure can be easily obtained.

When the first (meth) acrylic resin film 21 contains rubber particles, the (meth) acrylic resin composition containing rubber particles used in the production of the film can be obtained by combining methacrylic resin and rubber particles with In addition to being obtained by mixing such as melt-kneading, rubber particles may be first prepared and obtained by a method of polymerizing a monomer composition that is a raw material of a methacrylic resin in the presence of the rubber particles.

(3) 2nd (meth) acrylic resin film

The second (meth) acrylic resin film 22 is a protective film laminated on the other side of the polarizer 10. When a polarizing plate is applied to a liquid crystal panel, any of the polarizing plate on the identification side and the polarizing plate on the backlight side Both are protective films disposed on the liquid crystal cell side.

In this way, the polarizing plate of the present invention is a film composed of the same kind of resin on both sides of the protective film, and thereby, the behavior of the change in size becomes vertical symmetry, which can prevent the polarizing plate from warping, and thus prevent the liquid crystal panel from warping. song. Therefore, it is useful to prevent display defects caused by warping of the panel, such as light leakage caused by the panel contacting a bezel or the like. It is especially effective for IPS mode. Here, the so-called films made of the same kind of resin may be different films as long as they are made of the same kind of resin. For example, the composition of the resin may be different, and the amount and type of additives formulated in the film may also be different. Can be different.

The second (meth) acrylic resin film 22 is different from the first (meth) acrylic resin film 21 and is a protective film that improves the transmittance of ultraviolet rays. Specifically, the content of the ultraviolet absorber in the film is 1% by weight or less, more preferably 0.5% by weight or less, more preferably 0.2% by weight or less, particularly It is desirable not to contain an ultraviolet absorber.

The content of the ultraviolet absorber of the second (meth) acrylic resin film 22 is relatively reduced compared with the first (meth) acrylic resin film 21, or the second (meth) acrylic resin film 22 is set to The polarizing plate of the present invention which does not contain an ultraviolet absorber is advantageous in the following points, for example.

[a] It is possible to prevent or suppress the adhesion / contamination of the foreign matter derived from the ultraviolet absorber as described above. That is, it is estimated that the adhesion / contamination of the foreign matter is caused by evaporation of the (meth) acrylic resin when the (meth) acrylic resin film is heated and melted when the (meth) acrylic resin film is produced by the melt extrusion method. Particles produced by re-solidification into particles are attached to the surface of the film, caused by the liquid substance containing the ultraviolet absorber dripping and adhering to the film surface or being mixed in the film. The content of the ultraviolet absorber can be prevented and suppressed by extremely suppressing the content of the ultraviolet absorber. Adhesion / contamination of such foreign matter.

In addition, an unstretched film of a (meth) acrylic resin is produced by a melt extrusion method, and when it is subjected to a stretching treatment, it is also possible to prevent or suppress the adhesion / contamination of foreign matter as described above. After the (meth) acrylic resin film is produced by the melt extrusion method as described above, in order to impart desired optical characteristics or mechanical characteristics, stretching treatment may be performed. The extension processing can be performed by conventional methods, such as one-axis extension, two-axis extension, and the like. Examples of the stretching direction include a mechanical moving direction (MD) of the unstretched film, a direction (TD) perpendicular thereto, and a direction oblique to the mechanical moving direction. The biaxial extension system can be a simultaneous biaxial extension in two extension directions, or a sequential biaxial extension in one direction and then in other directions.

Especially the two (meth) acrylics that the polarizer has In the resin film, by suppressing the content of the ultraviolet absorber of the second (meth) acrylic resin film 22 disposed on the liquid crystal cell side when it becomes a liquid crystal panel, it is possible to suppress Cross Nicol (Cross Nicol) formed in the liquid crystal panel. ) Contains foreign matter. In this way, it is possible to effectively prevent a decrease in visibility such as light leakage during black display of the liquid crystal display device.

[b] Since the content of the ultraviolet absorber of the second (meth) acrylic resin film 22 is low (preferably without an ultraviolet absorbent), the first and second (methyl) ) When the acrylic resin films 21 and 22 are on the polarizer 10, the type of the photopolymerization initiator of the adhesive is not selected, the adhesive can be easily hardened, and at the same time, the degree of hardening can be improved. Thereby, the adhesiveness of the obtained polarizer 10 of a polarizing plate with a (meth) acrylic-type resin film, and the mechanical strength of a polarizing plate can be improved. On the other hand, a sufficient amount of an ultraviolet absorber is added to the first (meth) acrylic resin film 21 to provide sufficient light resistance to the polarizing plate.

The second (meth) acrylic resin film 22 preferably has a high transmittance in ultraviolet rays, particularly in a wavelength region of 260 to 320 nm, and specifically has a transmittance of 20% or more in a wavelength region of 260 to 320 nm. Ideal, more than 30% is more ideal, more than 40% is more ideal. The wavelength region of 260 to 320 nm is a wavelength region generally sensitive to ultraviolet curable adhesives used for bonding polarizers and protective films. The high transmittance of this wavelength region can increase the curing speed and curing of ultraviolet curable adhesives. The amount of the photopolymerization initiator in the adhesive can be suppressed. Furthermore, in the present invention, the transmittance in the wavelength region of 260 to 320 nm is 20% or more, which means that at least one of the wavelength regions in the range of 260 to 320 nm has a transmittance of 20%. the above.

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

The in-plane phase difference value R ₀ and the thickness direction phase difference value R _th are defined by the following formulas, respectively.

R ₀ = (n _x -n _y ) × d

R _th = [(n _x + n _y ) / 2-n _z ] × dn _x is the refractive index in the in-plane retardation phase axis direction of the film, and n _y is the in-plane advancing phase axis direction (in-plane perpendicular to in-plane) The refractive index in the direction of the retardation phase axis), n _z is the refractive index in the thickness direction, and d is the thickness of the film.

Regarding the (meth) acrylic resin constituting the second (meth) acrylic resin film 22, the type when the ultraviolet absorber is contained, the thickness of the film, and other additives (such as rubber particles) blended in the film, the first The above description of the (meth) acrylic resin film 21. In particular, (meth) acrylic resin is easy to be charged, and it is easy to attach environmental foreign matter. Therefore, the second (meth) acrylic resin film 22 or the second (meth) acrylic resin film 22 is added in an amount of 0.01 to 10 weight. A part of the antistatic agent (layer) is preferable. Regarding the adhesion of foreign matter, similar to the foreign matter derived from the ultraviolet absorber, it can suppress the inclusion of foreign matter in the cross nicol formed on the liquid crystal panel, and can effectively prevent light leakage during the black display of the liquid crystal display device. Reduced visibility.

Whether the first (meth) acrylic resin film 21 and the second (meth) acrylic resin film 22 are used, the types and blending amounts of other additives, the types of ultraviolet absorbers, the (meth) acrylic resin The kind and the thickness of the film may be the same, and may be different at any one point or more.

(4) First and second adhesive layers

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

The component (hereinafter also simply referred to as a "curable component") that constitutes an ultraviolet curable adhesive and is cured by irradiation of ultraviolet rays may be an epoxy compound, an oxetane compound, or (meth) acrylic acid. Department of compounds and so on. Among these, as the above-mentioned adhesive, an ultraviolet-curable adhesive having an epoxy-based compound hardened by cationic polymerization is preferably used as a hardening component. The epoxy-based compound herein refers to a compound having an average of one or more, and preferably two or more epoxy groups in the molecule. The epoxy-based compound may be used singly or in combination of two or more kinds.

Examples of suitable epoxy-based compounds include alicyclic polyols obtained by hydrogenating an aromatic ring of an aromatic polyol, and hydrogenated epoxy compounds (having an alicyclic ring) obtained by reacting epichlorohydrin. Epoxy propylene ether of polyalcohols); such as aliphatic polyols or alkylene oxide adducts thereof Aliphatic epoxy compounds of poly (glycidyl ether); alicyclic epoxy compounds of epoxy compounds having one or more epoxy groups bonded to alicyclic rings in the molecule.

Epoxy compounds are easily available on the market, such as the "EPICOTE" series sold by the Japanese epoxy resin company, the "EPICLON" series sold by the DIC company, and the "EPOTOT" sold by Tohto Kasei Co. Series, "ADEKARESIN" series sold by ADEKA, "DENACOL" series sold by Nagase Chemical Co., "DOW EPOXY" series sold by Dow Chemical Co., and "DEPIKU" sold by Nissan Chemical Industries.

The above-mentioned alicyclic epoxy compounds can also be easily obtained in commercial products, such as the "CELLOXIDE" series and "CYCLOMER" series sold under the brand name, DAICEL Chemical Industry Co., and "CYRACURE" series sold by Dow Chemical Co. Wait.

The ultraviolet-curable adhesive is used instead of an epoxy-based compound that is hardened by cation polymerization, or a radically polymerizable (meth) acrylic compound is used as a hardening component at the same time. The (meth) acrylic compound is, for example, a (meth) acrylic acid ester monomer having at least one (meth) acryloxy group in the molecule and having at least one (meth) acrylfluorene group in the molecule. (Meth) acrylic acid monomer; (meth) acrylamide monomer having at least one (meth) acrylfluorene group and amidine bond in the molecule; obtained by reacting two or more kinds of compounds containing a functional group This is for compounds containing (meth) acrylfluorenyl groups, such as (meth) acrylic acid oligomers having at least two (meth) acrylfluorenyl groups in the molecule. (Meth) acrylic acid oligomers A (meth) acrylate oligomer having at least two (meth) acrylic alkoxy groups in the daughter. The (meth) acrylic compound may be used alone or in combination of two or more. The (meth) acrylic compound preferably contains a (meth) acrylamide monomer.

As the (meth) acrylamide monomer having at least one (meth) acrylfluorenyl group and amidine bond in the molecule, the following general formula (vi) is more preferable: CH ₂ = C (R ²⁸ ) -CONH _(2-i) -(LOR ²⁹ ) _{i is} an N-substituted fluorene-based monomer represented by general formula (vi). In the formula, R ²⁸ represents a hydrogen atom or a methyl group, L represents a methylene group or an ethyl 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 amidoamine-based monomer represented by the general formula (vi) include N-hydroxyethyl (meth) acrylamidonium and N-hydroxymethyl (meth) acrylamidoamine. , N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, N-methoxyethyl (meth) acrylamide, N-ethoxy Ethyl (meth) acrylamide and the like. These N-substituted amidoamine-based monosystems may be used alone or in combination of two or more.

The N-substituted fluorene amine-based monomer represented by the general formula (vi) is preferable because it exhibits good adhesion to polarizers with low moisture content and protective films using materials with low moisture permeability. Among the exemplified monomers, N-hydroxyethyl (meth) acrylamide is more preferable because it exhibits particularly good adhesion.

The radically polymerizable compound may contain a (meth) acrylic compound other than the N-substituted amidoamine-based monomer represented by the general formula (vi). Substances, that is, N-substituted fluorene-amine monomers other than the N-substituted fluoramine-based monomers represented by the general formula (vi), various monofunctional (meth) acrylates, amines having an aromatic ring and a hydroxyl group, and amines Carbamate (meth) acrylate, polyester (meth) acrylate, various compounds having a (meth) acrylfluorenyl group, and the like. However, in consideration of the adhesiveness and water resistance of the adhesive layer, the ratio of the N-substituted amidoamine-based monomer represented by the general formula (vi) is 50 to 99 weight based on the total amount of the radical polymerizable compound. % Is more preferable, and 60 to 90% by weight is more preferable.

Examples of the N-substituted fluorene-amine monomer other than the N-substituted fluoramine-based monomer represented by the general formula (vi) include N-methyl (meth) acrylamide and N, N-dimethylamine. (Meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N -Hexyl (meth) acrylamide, aminomethyl (meth) acrylamide, aminoethyl (meth) acrylamide, thiol methyl (meth) acrylamine, thiol Ethyl (meth) acrylamidonium, N-acrylamidomorpholine, N-acrylamidopiperidine, N-methacrylamidopiperidine, N-acrylamidopyrrolidine (Pyrrolidine), and the like.

As the monofunctional (meth) acrylate having an aromatic ring and a hydroxyl group, various monofunctional (meth) acrylates having an aromatic ring and a hydroxyl group can be used. A hydroxyl group may exist as a substituent of an aromatic ring, and it is preferable to exist as a substituent of an organic group (hydrocarbon group, especially an alkylene group) in which an aromatic ring is bonded to a (meth) acrylate.

Examples of the monofunctional (meth) acrylate having an aromatic ring and a hydroxyl 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 a phenylepoxypropyl ether and a third butylphenyl group. Glycidyl ether, phenyl polyethylene glycol glycidyl ether and the like. Specific examples of the monofunctional (meth) acrylate having an aromatic ring and a hydroxyl group, such as 2-hydroxy-3-phenoxypropyl (meth) acrylate and 2-hydroxy-3-third (meth) acrylate Butylphenoxypropyl, 2-hydroxy-3-phenyl polyethylene glycol propyl (meth) acrylate, and the like.

The urethane (meth) acrylate is, for example, a reaction product between a (meth) acrylate having an isocyanate group and a single-terminal hydroxyl group of a diol compound. Examples of the diol compound include polyalkylene glycols such as polyurethane diol, polyester diol, polyether diol, polyethylene glycol, and polypropylene glycol.

Examples of the compound having a (meth) acrylfluorenyl group include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Alkyl (meth) acrylate having 1 to 12 carbons, such as isooctyl (meth) acrylate, isononyl (meth) acrylate, and lauryl (meth) acrylate; methoxyethyl (meth) acrylate (Meth) acrylate alkoxyalkyl ester-based monomers such as esters and ethoxyethyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12 (meth) acrylate -Hydroxylauryl esters and (4-hydroxymethylcyclohexyl) -methyl acrylate-containing monomers; maleic anhydride-containing monomers such as maleic anhydride and methylene succinic anhydride; acrylic acid Lactone adducts; styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamido-2-methylpropanesulfonic acid, (meth) acrylamidopropanesulfonic acid, (meth) Sulfopropyl acrylate and (meth) propylene Oxygen Sulfonic acid group-containing monomers such as naphthalenesulfonic acid; phosphate group-containing monomers such as 2-hydroxyethylpropenyl phosphonium phosphate; and the like. Further, for example, a maleimide group-containing monomer including maleimide, N-cyclohexylmaleimide, and N-phenylmaleimide; and (meth) acrylamidoethyl Ester, aminopropyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, tertiary butylaminoethyl (meth) acrylate, and 3- (meth) acrylate 3- Alkyl (meth) acrylic alkylamino alkyl monomers such as (3-pyridyl) propyl; N- (meth) acryloxymethyleneoxysuccinimide, N- (meth) propylene Nitrogen containing succinimide-based monomers such as fluorenyl-6-oxyhexamethylene succinimide and N- (meth) acrylfluorenyl-8-oxyoctamethylene succinimide, etc. Monomer.

(Meth) acryloxy group-containing (meth) acryloxy group-containing oligomers having at least two (meth) acryloxy groups in the molecule obtained by reacting two or more types of functional group-containing compounds A compound, that is, a compound containing a bis (meth) acryloxy group, is preferably a polyfunctional group in order to improve the water resistance of the adhesive layer. In consideration of the water resistance of the adhesive layer, a compound containing a bis (meth) acryloxy group is more preferably hydrophobic. As the hydrophobic di (meth) acryloxy group-containing compound, particularly the hydrophobic polyfunctional compound containing the di (meth) acryloxy group, such as tricyclodecane dimethanol diacrylate, ethyl Diethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) Base) 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) propylene Acrylates, 1,9-nonanediol di (meth) acrylate, glycerol di (meth) acrylate, ethylene oxide modified glycerol tri (meth) acrylate, ethylene oxide Alkane-modified diglycerol tetra (meth) acrylate, 2- (2-vinyloxyethoxy) ethyl (meth) acrylate, bisphenol A-ethylene oxide adduct bis (methyl) ) Acrylate, trimethylolpropane tri (meth) acrylate, neopentyl glycol (meth) acrylic acid adduct of hydroxypivalic acid, ethylene oxide modified trimethylolpropane tri (methyl) Acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, isocyanurate ethylene oxide modified tri (meth) acrylate, ε -Caprolactone modified tri ((meth) acryloxyethyl) isocyanurate, 1,1-bis ((meth) acryloxymethyl) ethyl isocyanate, (methyl) Polymer of 2-hydroxyethyl acrylate and 1,6-diisocyanate hexane, 9,9-bis [4- (2- (meth) acryloxyethoxy) phenyl] fluorene, etc. .

The proportion of the compound containing a di (meth) propenyloxy group is preferably 5 to 50% by weight, and more preferably 9 to 40% by weight based on the total amount of the radical polymerizable compound. When the proportion is less than 5% by weight, a sufficient effect of improving water resistance may not be obtained. On the other hand, when it exceeds 50% by weight, a sufficient effect of improving adhesion may not be obtained.

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

The ultraviolet-curable adhesive may contain an oxa compound together with or instead of an epoxy compound and / or a (meth) acrylic compound. Cyclobutane compounds. The oxetane compound can also be easily obtained from commercial products, such as the "ARON OXETANE" series sold by Toa Kosei Co., Ltd., and the "ETERNACOLL" series sold by Ube Kosan Co., Ltd. under the trade names.

When the ultraviolet curable adhesive contains a curable component such as an epoxy-based compound that is cured by cation polymerization, it is preferable to include a photocationic polymerization initiator. Examples of the photocationic polymerization initiator include an aromatic diazonium salt; an onium salt such as an aromatic iodonium salt and an aromatic sulfonium salt; an iron-aromatic hydrocarbon complex; and the like. When the ultraviolet curable adhesive contains a radical polymerizable curable component such as a (meth) acrylic compound, it is preferable to include a photoradical polymerization initiator. As the photoradical polymerization initiator, for example, a hydrogen extraction type or a cracking type, such as an acetophenone-based initiator, a benzophenone-based initiator, a benzoin-ether-based initiator, a thioanthrone-based initiator, and an xanthracene Ketones, fluorenone, camphor quinone, benzaldehyde, anthraquinone, etc. These initiators may include two or more different types of photocationic polymerization initiators and photoradical polymerization initiators, or a combination of photocationic polymerization initiators and photoradical polymerization initiators may be used as necessary. The wavelength region induced by the photopolymerization initiator is mostly 260 to 380 nm, and in particular, it has a spectral peak near 320 nm.

Cationic polymerization initiators can also easily obtain commercially available products, such as the "KAYARAD" series sold by Nippon Kayakusho, the "CYRACURE" series sold by Union Carbide, and the ones sold by SAN-APRO, respectively. Photoacid generator "CPI" series, photoacid generators "TAZ", "BBI" and "DTS" sold by Green Chemical Company, "ADEKA OPTOMER" series sold by ADEKA company, and Rhodia company sold "RHODORSIL" series, etc.

The ultraviolet-curing adhesive may contain a cationic polymerization accelerator such as a polyhydric alcohol, a photosensitizer, an ion trapping agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow modifier, and a plasticizer, if necessary. Additives, defoamers, antistatic agents, leveling agents, solvents and other additives.

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

Applying a UV-curable adhesive 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 via the applied UV-curable adhesive layer, After the films are laminated, ultraviolet rays are irradiated and the adhesive layer is hardened to obtain a polarizing plate. This bonding operation is performed after the polarizer 10 and the first (meth) acrylic resin film 21 are bonded together, and then the second (meth) acrylic resin film 22 is bonded, and three sheets can be aligned and overlapped at the same time. Bonded by irradiating ultraviolet rays. The ultraviolet rays are preferably irradiated at least once from the second (meth) acrylic resin film 22 side, and are preferably from the viewpoint of curing the adhesive. As the ultraviolet light source, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, a metal halide lamp, and the like can be used.

Before bonding, the first and second (meth) acrylic resin films 21 and 22 are bonded to the polarizer 10 and the polarizer 10 and the first and second (meth) acrylic resin film 21 At least one of the bonding surfaces of 22 and 22 can be subjected to a corona discharge treatment, a plasma irradiation treatment, an electron beam irradiation treatment, Other surface activation treatments.

(5) Adhesive layer

The polarizing plate of the present invention may be provided with an adhesive on the outer surface of the second (meth) acrylic resin film 22 (the surface opposite to the polarizing plate 10) for bonding the polarizing plate to other members such as a liquid crystal cell. Layer 30. The adhesive used in the adhesive layer 30 is, for example, a (meth) acrylic adhesive, a urethane adhesive, a polysiloxane adhesive, a polyester adhesive, a polyamide adhesive, a Among the ether-based adhesives, fluorine-based adhesives, and rubber-based adhesives, a (meth) acrylic-based adhesive is preferably used from the viewpoints of transparency, adhesion, reliability, and reworkability.

The adhesive layer 30 can be formed on the second (meth) acrylic resin film 22 by applying the adhesive in the form of an organic solvent solution, and drying it. A method for transferring the sheet-shaped adhesive on the processed plastic film (also referred to as a release film) to the second (meth) acrylic resin film 22 may be provided. In either method, it is preferable to laminate the outer surface of the adhesive layer 30 behind the second (meth) acrylic resin film 22 and attach a release film for protecting the surface. The thickness of the adhesive layer 30 is usually 2 to 40 μm.

The release film may be a film composed of a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, or a polyester-based resin such as polyethylene terephthalate. Among them, a stretched film of polyethylene terephthalate is preferable.

(6) Coating layer

The polarizing plate of the present invention is for imparting desired optical characteristics to the polarizing plate. Or other characteristics, the 1st (meth) acrylic-type resin film 21 may have a coating layer on the outer surface (surface on the opposite side to the polarizer 10). 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 a surface treatment layer on the surface of the first (meth) acrylic resin film 21 is not particularly limited, and a conventional method can be used.

<LCD panel>

The liquid crystal panel of the present invention includes a liquid crystal cell and a polarizing plate of the present invention arranged on at least one side of the liquid crystal cell. An example of the layer structure of the liquid crystal panel of this invention is shown in FIG. The liquid crystal panel 2 shown in FIG. 2 is a polarizing plate disposed on both sides of the liquid crystal cell 40. The polarizing plate 1 shown in FIG. 1 is used, or as described above, only one of the polarizing plates is used in the present invention. It is preferable to use at least the polarizing plate on the identification side, and use the polarizing plate of the present invention.

The polarizing plate 1 is arranged in the liquid crystal panel 2 such that the second (meth) acrylic resin film 22 becomes the liquid crystal cell 40 side. Thereby, while maintaining the light resistance of the liquid crystal panel 2, it is possible to suppress the inclusion of foreign substances in the crossed Nicols.

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. As described above, the IPS mode is more preferable. In the IPS mode, a nematic liquid crystal that is uniformly aligned in the absence of an electric field, and is driven by a lateral electric field to display an image, has the advantage of having a wider viewing angle when compared with other driving modes. Because the color change of the image at the angle of the observation screen (also known as the color deviation in the oblique direction) is large, this point can be achieved by using The polarizing plate of the directional second (meth) acrylic resin film 22 is improved.

(example)

Hereinafter, the present invention will be described more specifically by showing examples and comparative examples, but the present invention is not limited to these examples. The transmittance of the (meth) acrylic resin film and the polarizing plate was measured by the following method.

[Measurement of transmittance of (meth) acrylic resin film]

The transmittance in the ultraviolet region (190 to 380 nm) of the (meth) acrylic resin film 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 a UV-visible spectrophotometer "V7100" manufactured by JASCO Corporation. The measurement is performed in the spectrometry mode with the Glan-Thompson polarizer removed. After measuring the transmittance at an arbitrary sample angle, the sample is rotated 90 degrees to determine the transmittance. The average value was calculated to calculate the transmittance of the polarizing plate.

<Example 1>

(1) Production of the first (meth) acrylic resin film

For the (meth) acrylic resin, a copolymer of methyl methacrylate / methyl acrylate = 96% / 4% (weight ratio) was prepared. In addition, for the rubber particles, the innermost layer is prepared by using a hard polymer polymerized with a small amount of allyl methacrylate in methyl methacrylate. The intermediate layer is made of butyl acrylate as the main component, and then benzene is used. It consists of a soft elastomer polymerized by ethylene and a small amount of allyl methacrylate. The outermost layer is made of methyl methacrylate. An elastomer particle having a three-layer structure composed of a hard polymer polymerized with a small amount of ethyl acrylate has an average particle diameter of 240 nm up to the elastomer of the intermediate layer, and the innermost layer and the middle of the rubber particle The total weight of the layers is 70% of the total particles.

68.5% by weight of the (meth) acrylic resin, 29.6% by weight of the rubber particles, and 1.9% by weight of the ultraviolet absorber "ADEKA STAB LA31" manufactured by ADEKA were mixed with a super mixer and melt-kneaded with a biaxial extruder to form pellets . Put the particles into 65mm A 1-axis extruder was extruded through a T-die at a set temperature of 275 ° C, and cooled by sandwiching both sides of two polishing roller films having a mirror surface to obtain a first (meth) acrylic resin film having a thickness of 40 μm.

In the above-mentioned melt extrusion molding, the evaporate near the T-die after 100 hours from the extrusion of the resin, when visually confirmed, it was found that the evaporate accumulated a lot, and the obtained first (meth) acrylic resin There is a risk that vapors will adhere to the film. The maximum transmittance (%) in the wavelength range of 190 to 380 nm of the obtained first (meth) acrylic resin film was 15.9%. The transmittance of the obtained first (meth) acrylic resin film in a wavelength region of 190 to 380 nm is shown in FIG. 3.

(2) Production of 2nd (meth) acrylic resin film

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

Evaporation near the T-die after 100 hours from the extrusion of the resin. When visually confirmed, no evaporation was observed. Therefore, it can be judged that the second (meth) acrylic resin film obtained will not have Adhesion / mixing of vapors Into the risk. The maximum transmittance (%) of the obtained second (meth) acrylic resin film in the wavelength region of 260 to 320 nm was 78.7% at 316 nm. The transmittance of the obtained second (meth) acrylic resin film in a wavelength region of 190 to 380 nm is shown in FIG. 4.

(3) Production of polarizing film

A polyvinyl alcohol film having an average degree of polymerization of about 2400, a degree of saponification of 99.9 mol% or more, and a thickness of 75 μm was immersed in pure water at 30 ° C, and then the weight ratio of iodine / potassium iodide / water was 0.02 / 2/100 at 30 ° C. Water solution. Then, it was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 12/5/100 at 56.5 ° C. Next, it was washed with pure water at 8 ° C, and then dried at 65 ° C to obtain a polarizing film having iodine adsorbed and aligned on the polyvinyl alcohol film. The stretching is mainly performed in the steps of iodine dyeing and boric acid treatment, and the total stretching ratio is 5.3 times. The thickness of the obtained polarizing film is 27 μm.

(4) Fabrication of polarizing plate

After the corona treatment is performed on the bonding surface of the first (meth) acrylic resin film obtained in (1) above, the corona-treated surface is coated with an ultraviolet curing adhesive that initiates polymerization in a wavelength region of 260 to 320 nm. ("ARONIX" made by Toa Gosei Co., Ltd.). Similarly, after the corona treatment is performed on the bonding surface of the second (meth) acrylic resin film obtained in the above (2), the same ultraviolet curing adhesive is applied to the corona treatment surface. Then, using a bonding roller, the first (meth) acrylic resin film coated with the ultraviolet curing adhesive was bonded to the side of one side of the polarizing film obtained in the above (3) with the ultraviolet curing adhesive layer side. The second (meth) acrylic resin film coated with the ultraviolet curing adhesive is bonded to the surface of the other side on the ultraviolet curing adhesive layer side. Then, ultraviolet rays were irradiated from the second (meth) acrylic resin film side, and the ultraviolet curing adhesive layers on both sides were cured to obtain a polarizing plate. The ultraviolet irradiation is performed so that the cumulative light amount in the wavelength region of 260 to 320 nm becomes 200 mJ / cm ² . The maximum transmittance (%) of the obtained polarizing plate in the wavelength region of 260 to 380 nm was 2.3%. In addition, even when the obtained polarizing plate was cut with scissors, no defect of peeling of the (meth) acrylic resin film from the polarizing film was generated, and it was confirmed that the adhesive layers on both sides were sufficiently hardened.

<Example 2>

(1) Production of the first (meth) acrylic resin film

A first (meth) acrylic resin film was produced in the same manner as in (1) of Example 1 except that the thickness was 80 μm. In the above-mentioned melt extrusion molding, the evaporation near the T-die from the time when the resin was extruded until 100 hours elapsed, when it was visually confirmed that the evaporation accumulated a lot, so the first (meth) acrylic acid obtained Resin film may adhere or mix with vapors. The maximum transmittance (%) of the obtained first (meth) acrylic resin film in the wavelength region of 190 to 380 nm was 3.5%.

(2) Production of 2nd (meth) acrylic resin film

A second (meth) acrylic resin film was produced in the same manner as in (2) of Example 1 except that the thickness was 80 μm. From the time when the resin was extruded until the evaporate near the T-die for 100 hours, it was visually confirmed that there was no accumulation of the evaporate. Therefore, it can be judged that the second (meth) acrylic resin film obtained had no Evaporation may be attached / mixed. The maximum transmittance (%) of the obtained second (meth) acrylic resin film in the wavelength region of 260 to 320 nm was 75.1% at 316 nm.

(3) Fabrication of polarizing plate

A polarizing plate was produced in the same manner as in (4) of Example 1 except that the first and second (meth) acrylic resin films produced in the above (1) and (2) were used. The maximum transmittance (%) of the obtained polarizing plate in the wavelength region of 260 to 380 nm was 0.3%. In addition, even when the obtained polarizing plate was cut with scissors, no defect of peeling of the (meth) acrylic resin film from the polarizing film was generated, and it was confirmed that the adhesive layers on both sides were sufficiently hardened.

<Example 3>

(1) Production of the first (meth) acrylic resin film

A first (meth) acrylic resin film was produced in the same manner as in (1) of Example 1 except that the thickness was 80 μm. In the above-mentioned melt extrusion molding, the evaporation near the T-die from the beginning of extruding the resin to 100 hours has elapsed. When visually confirming, it can be seen that a large amount of evaporation accumulates, so the first (methyl) obtained is The acrylic resin film is likely to cause adhesion of vapors. The maximum transmittance (%) of the obtained first (meth) acrylic resin film in the wavelength region of 190 to 380 nm was 3.5%.

(2) Production of 2nd (meth) acrylic resin film

Except for using a thickness of 80 μm and using 69.9% by weight of a (meth) acrylic resin, 29.6% by weight of the above-mentioned rubber particles, and 0.5% by weight of an ultraviolet absorber “ADEKA STAB LA31” manufactured by ADEKA Corporation as the material for forming the film, it is the same as in the examples. (2) of 1 In the same manner, a second (meth) acrylic resin film was produced. From the beginning of the extrusion of the resin to the evaporation of the vicinity of the T-die for 100 hours, when it was visually confirmed, the accumulation of the evaporation was only a small amount, so it can be judged that the obtained second (meth) acrylic resin film has evaporation Attach / mix The probability of entry is extremely low. The maximum transmittance (%) of the obtained second (meth) acrylic resin film in the wavelength region of 260 to 320 nm was 21.3% at 266 nm.

(3) Fabrication of polarizing plate

A polarizing plate was produced in the same manner as in (4) of Example 1 except that the first and second (meth) acrylic resin films produced in the above (1) and (2) were used. The maximum transmittance (%) of the obtained polarizing plate in the wavelength region of 260 to 380 nm was 0.14%. In addition, even when the obtained polarizing plate was cut with scissors, no defect of peeling of the (meth) acrylic resin film from the polarizing film was generated, and it was confirmed that the adhesive layers on both sides were sufficiently hardened.

<Example 4>

(1) Production of the first (meth) acrylic resin film

A first (meth) acrylic resin film was produced in the same manner as in (1) of Example 1 except that the thickness was 60 μm. In the above-mentioned melt extrusion molding, when the evaporate near the T-die from the time of extruding the resin to 100 hours passed was visually confirmed, it was seen that the evaporate accumulated a lot. Resin film may adhere or mix with vapors. The maximum transmittance (%) of the obtained first (meth) acrylic resin film in the wavelength region of 190 to 380 nm was 7.5%. The transmittance of the obtained first (meth) acrylic resin film in a wavelength region of 190 to 380 nm is shown in FIG. 6.

(2) Production of 2nd (meth) acrylic resin film

First, a (meth) acrylic thermoplastic resin is manufactured by the following method. Methyl methacrylate (Wako Pure Chemical Grade) was distilled at a reduced pressure of 0.01 MPa and 40 ° C to remove the inhibitor. Then, in a 50L tank, prepare the packet Contains distilled methyl methacrylate / N-phenylmaleimide (Wako Pure Chemical Special Grade) / cyclohexylmaleimide (Wako Pure Chemical Special) / m-xylene (Wako Pure Chemical Special, below mXy ) = 48.6% / 4.8% / 6.6% / 40% (weight ratio) of the mixed monomer solution, in which nitrogen gas was bubbled at a rate of 100 mL / min for 12 hours to remove dissolved oxygen. The mixed monomer solution was moved to a nitrogen-substituted 60 L reactor, and the temperature was raised to 130 ° C. Then, at the same temperature and at a rate of 1 kg / hour, 0.12% by weight of a polymerization initiator [Nippon Oil & Fat Co., Ltd. "PERBUTYL O"] was dissolved in an mXy 12% by weight initiator solution, polymerization was performed, and after 8 hours, the reactor Cool to 50 ° C.

Then, 500 L of methanol was charged into a 1 m ³ reactor, and the polymerization solution was injected for 5 hours to precipitate a polymer. Then, it stirred for 2 hours, and filtered under reduced pressure. 300 L of methanol was poured into the polymer powder containing methanol after filtration under reduced pressure, and the mixture was stirred. Then, the solution was filtered under reduced pressure, and a powder containing methanol was collected and dried under a condition of a pressure reduction of 0.03 MPa and 80 ° C. in a 0.3 m ³ UNICAL vacuum dryer. The dried powder was granulated in a biaxial extruder at 250 ° C. to obtain a granular (meth) acrylic thermoplastic resin.

Then, the granular (meth) acrylic thermoplastic resin was put into a biaxial extruder, melt-kneaded at 260 ° C, extruded through a T-die at a set temperature of 255 ° C, and mirror-cooled rollers were used for surface rotation. Printed as unstretched film. Then, this unstretched film was sequentially stretched (MD stretching magnification: 1.8 times, TD stretching magnification: 2.5 times) using a melt stretching apparatus to obtain a second (meth) acrylic resin film having a thickness of 40 μm.

In the above-mentioned melt extrusion molding, from extruding the resin to 100 When the vapors near the T-die of the hour are visually confirmed, since no vapors have been accumulated, it can be judged that the second (meth) acrylic resin film obtained does not have vapors attached or mixed. Fear. The maximum transmittance (%) of the obtained second (meth) acrylic resin film in the wavelength region of 260 to 320 nm was 84.2% at 320 nm. The transmittance of the obtained second (meth) acrylic resin film in a wavelength region of 190 to 380 nm is shown in FIG. 7.

(3) Fabrication of polarizing plate

A polarizing plate was produced in the same manner as in (4) of Example 1 except that the first and second (meth) acrylic resin films produced in the above (1) and (2) were used. The maximum transmittance (%) of the obtained polarizing plate in the wavelength region of 260 to 380 nm was 1.0%. In addition, even when the obtained polarizing plate was cut with scissors, no defect of peeling of the (meth) acrylic resin film from the polarizing film was generated, and it was confirmed that the adhesive layers on both sides were sufficiently hardened.

<Comparative Example 1>

As the first and second (meth) acrylic resin films, a polarizing plate was produced in the same manner as in (4) of Example 1 except that the (meth) acrylic resin film produced in (1) of Example 2 was used. The obtained polarizing plate had a maximum transmittance (%) in a wavelength range of 260 to 380 nm of 0.1%. The obtained polarizing plate-based adhesive layer had insufficient hardening, and when the polarizing plate was cut with scissors, a defect in which the (meth) acrylic resin film was peeled from the polarizing film occurred.

<Comparative Example 2>

(1) Production of (meth) acrylic resin film

Equipped with a stirring device, temperature sensor, cooling tube, and nitrogen introduction tube Into a 30L reaction kettle, put 8000g of methyl methacrylate (MMA), 2000g of methyl 2- (hydroxymethyl) acrylate (MHMA), and 10,000g of toluene. Pass nitrogen gas through it, and raise the temperature to 105 ° C. Under reflux, 10.0 g of triamylperisonononanoate peroxide ("Lupasol 570" manufactured by ATOFINA Kyoto) was added as an initiator, and a solution of 20.0 g of initiator and 100 g of toluene was added dropwise over 4 hours, and the mixture was refluxed. Solution polymerization was carried out at a lower temperature (about 105 to 110 ° C), and it took 4 hours to mature.

To the obtained polymer solution, 10 g of a stearyl phosphate / distearyl phosphate mixture ("Phoslex A-18" manufactured by Sakai Chemical Co., Ltd.) was added, and cyclic condensation was performed under reflux (approximately 90 to 110 ° C) for 5 hours. After the reaction, the polymer solution obtained by the above-mentioned cyclization condensation reaction is introduced at a processing rate of 2.0 kg / hour in terms of resin amount, and introduced into a barrel temperature of 260 ° C, a number of rotations of 100 rpm, and a pressure reduction degree of 13.3 to 400 hPa (10 to 300 mmHg) Exhaust-type screw two-shaft extruder with one rear exhaust and four front exhausts (φ = 29.75mm, L / D = 30). Cyclic condensation reaction and devolatization are performed in this extruder. As a component, transparent (meth) acrylic resin particles containing a lactone ring were obtained by extrusion.

The lactone cyclization ratio of the obtained (meth) acrylic resin particles containing a lactone ring was 97.0%, the mass average molecular weight was 147700, the melt flow rate was 11.0 g / 10 minutes, and the Tg (glass transition temperature) was 130 ° C .

In the extruder, the (meth) acrylic resin particles containing the lactone ring obtained above were supplied, and 100% by weight of the (meth) acrylic resin particles containing the lactone ring were mixed with ultraviolet light manufactured by Japan's CHIBA Special Chemicals 1% by weight of absorbent (TINUVIN1577) and 1% by weight of UV absorber "ADEKA STAB LA31" manufactured by ADEKA Corporation. The film was extruded from a T-die at a die temperature of 250 ° C., and was drawn out by cooling with a cooling roller to obtain a film having a thickness of 120 μm. Thereafter, a sequential biaxial extruder was used to perform 1.8 times the longitudinal stretching (heating temperature of 140 ° C) and then 2.4 times the transverse stretching (heating temperature of 140 ° C) to obtain a biaxially stretched film having a thickness of 40 μm. (Meth) acrylic resin film.

In the above-mentioned melt extrusion molding, when the vapors near the T-die from the time of extruding the resin to 100 hours have been visually confirmed, a large amount of vapors can be accumulated, so the (meth) acrylic resin obtained There is a risk that vapors will adhere to the film. The maximum transmittance (%) of the obtained (meth) acrylic resin film in the wavelength region of 190 to 380 nm was 24.3% at 274 nm. The transmittance of the obtained (meth) acrylic resin film in a wavelength region of 190 to 380 nm is shown in FIG. 5.

(2) Fabrication of polarizing plate

After the corona treatment was performed on the bonding surface of the (meth) acrylic resin film obtained in the above (1), an easy-adhesion layer with a thickness of 100 nm was formed on the corona-treated surface. The easy-adhesive layer is based on 100 parts by weight of a silane coupling agent "APZ-6601" manufactured by Toray Dow Silicone Co., Ltd., and a solution prepared by adding 66.7 parts by weight of isopropyl alcohol is applied to the corona treated surface with wire rod # 5. Volatile components are formed by evaporation.

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

Claims (8)

A polarizing plate includes a polarizer, a first (meth) acrylic resin film laminated on one surface of the polarizer, and a second film laminated on the other surface of the polarizer and facing the liquid crystal cell side. (Meth) acrylic resin film; wherein the first (meth) acrylic resin film contains an ultraviolet absorber and has a transmittance of 20% or less in the entire region of the wavelength range of 190 to 380 nm; the second (meth) ) The acrylic resin film does not contain an ultraviolet absorber. The polarizing plate according to item 1 of the scope of patent application, wherein the transmittance of the second (meth) acrylic resin film in a wavelength region of 260 to 320 nm is 20% or more. The polarizing plate according to item 1 of the scope of patent application, wherein the first and second (meth) acrylic resin films are laminated on the polarizer with an adhesive layer formed of an ultraviolet curable adhesive. . The polarizing plate according to item 1 of the scope of patent application, wherein the maximum value of the transmittance in the wavelength region of 260 to 380 nm is 3% or less. The polarizing plate as described in item 1 of the scope of patent application further includes an adhesive layer laminated on the outer surface of the aforementioned second (meth) acrylic resin film. The polarizing plate as described in the first item of the patent application range further includes a coating layer laminated on the outer surface of the aforementioned first (meth) acrylic resin film. A liquid crystal panel includes a liquid crystal cell and a polarizing plate according to any one of claims 1 to 6 of a patent application range arranged on at least one side of the liquid crystal cell. The liquid crystal panel according to item 7 of the scope of the patent application, wherein the liquid crystal cell is a liquid crystal cell in an IPS (transverse electric field effect) mode.