TW201329585A - Polarizing plate and image display device comprising the same - Google Patents

Abstract

Disclosed are a polarizing plate and an image display device including the same. The polarizing plate is prepared of a composition for forming an alignment layer which includes a polarizer layer; a binder layer formed on at least one face of the polarizer layer; and a retardation film having a structure in that a liquid crystal layer, an alignment layer and a substrate are laminated in order, wherein the liquid crystal layer is adhered to the binder layer, and wherein the alignment layer includes an adhesion enhancer having an isocyanate group and (meth)acrylate group at terminals thereof, and wherein the isocyanate group and (meth)acrylate group are bondable to a reactive group on a surface of the substrate and a reactive group of a liquid crystal compound in the liquid crystal layer, respectively. Thereby, it is capable of providing a polarizing plate having reduced thickness manufactured by a simple process and an image display device including the same.

Description

Polarizing plate and image display device having the same

The priority of the Korean Patent Application No. 10-2011-0138628 filed on Dec. 20, 2011, and the Korean Patent Application No. 10-2011-0138645 filed on Dec. 20, 2011 The entire disclosure is hereby incorporated by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing plate and an image display apparatus including the same, and more particularly to a polarizing plate having a reduced thickness by a simple process manufacturing, and an image including the polarizing plate Display device.

Description of the Related Art In general, three-dimensional image display technology is adapted to binocular parallax, and binocular parallax is the most important factor for recognizing three-dimensional effects at close range.
The principle of binocular parallax substantially means a method of using at least two cameras for acquiring stereoscopic images to obtain left and right images respectively viewed by the left and right eyes of the viewer at different angles; The image is separated and the separate image is transferred to the viewer's eyes. The human eye recognizes the object through the retina at different angles, and then synthesizes the two accepted images in the brain, thereby enabling the above process.
The image display device is, for example, a liquid crystal display device capable of embodying a stereoscopic image, and generally includes a patterned retardation film. Such patterned retardation films are provided with optical axes of respective pattern regions in different directions, thus enabling different images to be transferred to the left and right eyes of the viewer wearing the polarized glasses.
Fig. 1 schematically illustrates a patterned retardation film according to a conventional application. Herein, the patterned retardation film 100 is attached to the upper polarizing plate 200, in which light passing through the color filter layer passes through the upper polarizing plate.
In order to use a patterned retardation film in an image display device and to realize a stereoscopic image, the retardation film must be attached to the display device while the pattern (isolation) gap of the retardation film is matched to the pixel pitch of the color filter. However, this process cannot be easily performed, thus increasing the failure rate of the product during the process.
Here, the patterned retardation film 100 generally includes a structure in which the transparent substrate 110, the alignment layer 120, and the cured liquid crystal layer 130 are laminated on the upper polarizing plate 200 via the bonding layer 140 in this order. Meanwhile, the upper polarizing plate 200 includes a transparent substrate film 210, a first bonding layer 220 for bonding the transparent substrate film 210 to the polarizer 230, and a film for bonding the polarizer 230 to the transparent substrate or delay The second bonding layer 240 of the film 250.
However, since the retardation film has a low interlayer bonding force, when the protective film is removed after attaching the retardation film to the substrate using a binder, there is still a problem of causing delamination of the retardation film.

Accordingly, it is an object of the present invention to provide a polarizing plate incorporating a retardation film, the polarizing plate comprising a retardation film integrated with the polarizing plate.
Another object of the present invention is to provide a retardation film having excellent interlayer bonding force, which is integrated with a polarizing plate.
In order to accomplish the above object, the present invention provides the following.
(1) A polarizing plate prepared from a composition for forming a straightening layer, comprising: a polarizer layer; a bonding layer formed on at least one side of the polarizer layer; and a retardation film having a structure in which the structure The liquid crystal layer, the alignment layer, and the substrate are sequentially laminated, wherein the liquid crystal layer is attached to the adhesive layer, and wherein the alignment layer includes an isocyanate group and a (meth) acrylate group at a terminal thereof An adhesion enhancer of the group, and a reactive group in which the isocyanate group and the (meth) acrylate group are respectively bonded to the surface of the substrate and a reactive group of the liquid crystal compound in the liquid crystal layer.
(2) The polarizing plate according to the above (1), wherein the adhesion enhancer is at least one selected from the group consisting of compounds represented by the following formulas 1 to 4:
[Molecular Formula 1]


(wherein R1 and R2 are each independently hydrogen or methyl;
R 3 and R 7 are each independently an alkylene group having 1 to 10 carbon atoms, which is substituted or unsubstituted by a group selected from the group consisting of a ketone, an ester, and a thiol group;
R4 and R6 are each independently an alkylene group having 1 to 10 carbon atoms, which is substituted by a group selected from the group consisting of decylamine, ketone, ester, and thiol groups or Unsubstituted;
R5 is an alkylene group having 1 to 10 carbon atoms which is substituted or unsubstituted with an alkoxy group having 1 to 8 carbon atoms. ),
[Molecular Formula 2]


(wherein R7 and R8 are each independently hydrogen or methyl;
R9 and R11 are each independently an alkylene group having 1 to 10 carbon atoms, which is substituted or unsubstituted by a group selected from the group consisting of a ketone, an ester, and a thiol group;

R10 is (a) Or (b) Wherein E1 and E3 are each independently an alkyl group having 1 to 10 carbon atoms, which is substituted or unsubstituted by an alkoxy group having 1 to 8 carbon atoms, or has 1 to The alkoxy group of 8 carbon atoms, and E2 is an alkylene group having 1 to 10 carbon atoms, which is substituted or unsubstituted by an alkoxy group having 1 to 8 carbon atoms. ),
[Formula 3]

(wherein R12 is hydrogen or methyl,
R13 is an alkylene group having 1 to 10 carbon atoms which is substituted or unsubstituted by a group selected from the group consisting of a ketone, an ester, and a thiol group. )
[Molecular Formula 4]


(wherein R14 is hydrogen or methyl,
R15 is an alkylene group having 1 to 10 carbon atoms which is substituted or unsubstituted by a group selected from the group consisting of a ketone, an ester, and a thiol group. )
(3) The polarizing plate according to the above item (2), wherein the adhesion enhancer is a mixture of at least one of a compound represented by Formula 1 and a compound represented by Formulas 2 to 4.
(4) The polarizing plate according to the above item (1), wherein the alignment layer comprises a polymer having a cinnamate group as a light straightening agent.
(5) The polarizing plate according to the above (4), wherein the adhesion enhancer is included in an amount of 0.1 to 20 parts by weight with respect to 100 parts by weight of the optical straightening agent.
(6) The polarizing plate according to the above item (1), wherein the reactive group on the surface of the substrate is a group selected from the group consisting of a hydroxyl group, a thiol, a carboxyl group, a (meth) acrylate, an amine, and an epoxy group. At least one of them.
(7) The polarizing plate according to the above item (1), wherein the substrate is at least one selected from the group consisting of saponification, primer treatment, corona discharge, plasma treatment, and coating process. Handle the surface.
(8) The polarizing plate according to the above item (7), wherein the plasma treatment is selected from the group consisting of remote plasma treatment, direct plasma treatment, and monomer plasma treatment.
(9) The polarizing plate according to Item (1) above, wherein the alignment layer is bonded to the substrate via a urethane bond, a thiol-vinyl bond or a carbon-carbon saturation bond.
(10) The polarizing plate according to the above (9), wherein the urethane bond is an isocyanate group of the compound represented by any one of Formulas 1 to 4 in the alignment layer. It is formed by reacting with a hydroxyl group, a thiol, a carboxyl group, an amine or an epoxy group of the substrate.
(11) The polarizing plate according to the above (9), wherein the thiol-vinyl bond is a (meth) acrylate of a compound represented by any one of Formulas 1 to 4 in the alignment layer. The group is formed by reacting with a thiol group of the substrate.
(12) The polarizing plate according to the above (9), wherein the carbon-carbon saturated bond is a (meth) acrylate group represented by any one of Formulas 1 to 4 in the alignment layer. It is formed by reacting with a (meth) acrylate group of the substrate.
(13) The polarizing plate according to the above (1), wherein the liquid crystal layer is prepared using a liquid crystal compound having a carbon-carbon unsaturated bond, a hydroxyl group, an epoxy group or a cyano group.
(14) The polarizing plate according to Item (1) above, wherein the alignment layer is bonded to the liquid crystal layer via a urethane bond or a carbon-carbon saturation bond.
(15) The polarizing plate according to the above item (14), wherein the urethane bond is an isocyanate group of the compound represented by any one of Formulas 1 to 4 in the alignment layer. It is formed by reacting with a hydroxyl group, an epoxy group or a cyano group of the liquid crystal compound in the liquid crystal layer.
(16) The polarizing plate according to Item (14) above, wherein the carbon-carbon saturated bond is a (meth) acrylate of a compound represented by any one of Formulas 1 to 4 in the alignment layer. The group is formed by reacting with a carbon-carbon unsaturated bond of the liquid crystal compound in the liquid crystal layer.
(17) The polarizing plate according to the above (1), wherein the adhesive layer is prepared using an aqueous adhesive or a photocurable adhesive.
(18) The polarizing plate according to the above (1), wherein the bonding layer and the liquid crystal layer are bonded via a carbon-carbon saturation bond.
(19) The polarizing plate according to the above (1), wherein the retardation film is a patterned retardation film provided with the first and second patterns, the first and second patterns having optical axes different from each other.
(20) An image display device comprising the polarizing plate according to any one of the above items (1) to (19).
The polarizing plate of the present invention may have a retardation film integrated with the polarizing plate to reduce the failure rate during the process while achieving productivity improvement and reducing production cost.
The polarizing plate of the present invention may have a retardation film integrated with the polarizing plate to provide a film-type polarizing plate.
Since the retardation film integrated with the inventive polarizing plate has a very high interlayer bonding force, delamination can be greatly reduced during the process, thereby reducing the failure rate, thereby improving productivity.
The polarizing plate of the present invention exhibits excellent adhesion between the polarizer and the liquid crystal layer of the retardation film to improve durability reliability.
When an aqueous adhesive is used, the polarizing plate of the present invention can be environmentally friendly, and if a photocurable adhesive is used, productivity can be improved because of a simple process.
The polarizing plate of the present invention can have a good interlayer bonding force and use a backlight having high heat release for excellent definition.
The polarizing plate of the present invention can have a reduced thickness, and thus is efficiently utilized in an image display device having a short distance between a polarizing plate and a backlight.

The above and other objects, features and other advantages of the present invention will become more <RTIgt;
1 is a cross-sectional view schematically illustrating a conventional bonding method of a retardation film and a polarizing plate;
2 is a cross-sectional view schematically illustrating a polarizing plate incorporating a retardation film according to an embodiment of the present invention; and FIG. 3 is a view schematically illustrating a method for evaluating water repellency.

The polarizing plate of the present invention is prepared from a composition for forming a straightening layer including a polarizer layer; a bonding layer formed on at least one side of the polarizer layer; and having a liquid crystal layer, alignment a retardation film having a structure in which a layer and a substrate are sequentially laminated, wherein the liquid crystal layer is attached to the adhesive layer, and wherein the alignment layer includes an isocyanate group and a (meth) acrylate group at a terminal thereof An adhesion enhancer, and a reactive group in which the isocyanate group and the (meth) acrylate group are respectively bonded to the surface of the substrate and a reactive group of the liquid crystal compound in the liquid crystal layer. Thereby, it is possible to provide a polarizing plate having a reduced thickness which is manufactured by a simple process, and an image display device including the polarizing plate.
Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.
Fig. 2 is a cross-sectional view schematically illustrating a polarizing plate according to an embodiment of the present invention.
Regarding the polarizing plate 300 of the present invention, the transparent substrate film 310 positioned in the alignment liquid crystal layer may have a reactive group on the surface thereof, and the reactive group reacts with an isocyanate group or a (meth) acrylate group. Such a reactive group may include, for example, a hydroxyl group, a thiol, a carboxyl group, a (meth) acrylate, an amine or an epoxy group, and the like.
Therefore, as long as it has the above-mentioned reactive group, any substrate material used in the art can be modified without limitation. Furthermore, although substrate materials commonly used in the art are inherently free of such reactive groups as described above, this can also be used if the reactive group can be introduced on the surface via surface treatment generally known in the art. The substrate material is not limited.
For example, a film having excellent properties such as transmittance, mechanical strength, thermal stability, moisture resistance property, isotropic property or the like can be used. More particularly, there are films prepared from thermoplastic resins, including, for example, polyester resins such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, polybutylene Ethylene terephthalate, etc.; cellulose resin, such as diethyl cellulose, triethyl cellulose, etc.; polycarbonate resin; acrolein based resin, such as polymethyl (methyl) Acrylate, polyethyl (meth) acrylate, etc.; styrene resin, such as polystyrene, acrylonitrile-styrene copolymer, etc.; polyolefin resin, such as polyethylene, polypropylene, with ring Or norbornene-structured polyolefin, ethylene-propylene copolymer, etc.; vinyl chloride resin; guanamine resin, such as nylon, aromatic polyamine, etc.; quinone imine resin; polyether oxime resin; Polyetheretherketone resin; polyphenylene sulfide resin; vinyl alcohol resin; vinylidene chloride resin; vinyl butyral resin, allyl alcohol ester resin; polyacetal resin; epoxy resin, and the like. Further, a mixed film including the above thermoplastic resin can also be used. Alternatively, a film prepared from a thermosetting resin such as (meth)acryl aldehyde group, urethane acrylate, acrolein urethane, epoxy group or oxime resin, or the like can be used.
Among the above, the more widely used film is a film including triethylenesulfonyl cellulose (TAC), cycloolefin polymer (COP), polymethyl methacrylate (PMMA) polymer, and the like. Substrates prepared using TAC, COP, and/or PMMA are not inherently reactive on the surface thereof with reactive groups that react with isocyanates or (meth) acrylates. Therefore, the reactive group can be introduced onto the surface of the substrate via surface treatment. In the case of a hydroxyl group as an example of a reactive group, saponification of the surface of the TAC may introduce a hydroxyl group onto the surface, and the surface of the COP may be provided with a hydroxyl group by plasma treatment. Other surface treatments may include, for example, dry processes such as corona discharge, primer treatment, and the like; chemical processes such as alkaline treatment including saponification; coating processes to easily prepare a bonding layer, or the like. Preferably, the cellulose film is advantageously treated by an alkaline treatment comprising saponification, and the acrolein, polyolefin and/or polyester film can be processed by a dry process such as corona discharge or plasma treatment. . A more specific example of the plasma treatment may include at least one selected from the group consisting of remote plasma, direct plasma, and monomer plasma.
With respect to the inventive polarizing plate 300, a straightening layer 320 may be prepared from a composition for forming a straightening layer, the alignment layer including having an isocyanate group or a (meth) acrylate group bonded to the A reactive group on the surface of the transparent substrate film 310 and an adhesion enhancer of a reactive group of the liquid crystal compound in the liquid crystal layer 330.
The adhesion enhancer according to the present invention may include at least each (meth) acrylate group and an isocyanate group at its end, respectively. According to the invention, (meth) acrylate means acrylate, methacrylate or, alternatively, both acrylate and methacrylate.
Although the (meth) acrylate group and the isocyanate group in the adhesion enhancer according to the present invention do not inherently include (meth) acrylate groups and/or isocyanate groups at their ends, When the adhesion enhancer is mixed with the composition for forming the alignment layer, it can be produced by any additional process such as post-treatment, such as heating, before chemical bonding to the liquid crystal compound and the substrate (methyl The reactive group of the acrylate group or the isocyanate group can also be defined as the above "reactive group". For example, as a reactive group capable of generating an isocyanate group via heating, a pyrazole group attached to the end of the adhesion enhancer via a guanamine bond can be exemplified. The pyrazole group is separated during heating to thereby form an isocyanate group at the end of the adhesion enhancer.
The alignment layer 320 is a layer for inducing alignment of the liquid crystal, one side of which contacts the liquid crystal layer 330 and the other side of which contacts the substrate film 310. As mentioned above, the conventional problem is poor adhesion between the alignment layer and any layers that come into contact with it. On the other hand, the present invention can introduce an adhesion enhancer comprising an isocyanate group and a (meth) acrylate group at the end thereof on the alignment layer 320, so that the isocyanate group and The methyl acrylate groups are chemically bonded to the reactive groups exposed on the surface of the substrate film 310 and the liquid crystal layer 330, respectively, thereby enhancing the interlayer bonding force.
A more specific example of the adhesion enhancer according to the present invention may include at least one selected from the group consisting of compounds represented by the following formulas 1, 2, 3, and 4:
[Molecular Formula 1]


(wherein R1 and R2 are each independently hydrogen or methyl;
R 3 and R 7 are each independently an alkylene group having 1 to 10 carbon atoms which are substituted or unsubstituted by a group selected from the group consisting of a ketone, an ester, and a thiol group;
R4 and R6 are each independently an alkylene group having 1 to 10 carbon atoms substituted or unsubstituted by a group selected from the group consisting of decylamine, ketone, ester, and thiol groups;
R5 is an alkylene group having 1 to 10 carbon atoms which is substituted or unsubstituted with an alkoxy group having 1 to 8 carbon atoms. ),
[Molecular Formula 2]


(wherein R7 and R8 are each independently hydrogen or methyl;
R9 and R11 are each independently an alkylene group having 1 to 10 carbon atoms which are substituted or unsubstituted by a group selected from the group consisting of a ketone, an ester, and a thiol group;

R10 is (a) Or (b) Wherein E1 and E3 are each independently an alkyl group having 1 to 10 carbon atoms, which is substituted or unsubstituted by an alkoxy group having 1 to 8 carbon atoms, or has 1 to The alkoxy group of 8 carbon atoms, and E2 is an alkylene group having 1 to 10 carbon atoms, which is substituted or unsubstituted by an alkoxy group having 1 to 8 carbon atoms. ),
[Formula 3]

(wherein R12 is hydrogen or methyl,
R13 is an alkylene group having 1 to 10 carbon atoms which is substituted or unsubstituted by a group selected from the group consisting of a ketone, an ester, and a thiol group. )
[Molecular Formula 4]


(wherein R14 is hydrogen or methyl,
R15 is an alkylene group having 1 to 10 carbon atoms which is substituted or unsubstituted by a group selected from the group consisting of a ketone, an ester, and a thiol group. )
With respect to the inventive composition for forming the alignment layer, the adhesion enhancer represented by the above formulas 1 to 4 may include the compound represented by the formula 1 and the compound represented by the formulae 2 to 4. Mixture of at least one of them to ensure better interlayer bonding force.
More specific examples of the adhesion enhancer represented by the formulae 1 to 4 may include at least one selected from the group consisting of compounds represented by the following formulas 5 to 15:
[Molecular Formula 5]


[Formula 6]

[Formula 7]

[Molecular Formula 8]

[Formula 9]


[Formula 10]
　　　　　

[Formula 11]


[Formula 12]


[Formula 13]


[Formula 14]


[Formula 15]


The compound represented by the formula 4 and, as an example thereof, the compounds represented by the formulas 12, 13, 14 and 15 respectively have a dimethylpyrazole group at their ends, which are separated by heat treatment (for example, drying), It has an isocyanate group at its end.
The composition for creating the alignment layer may include an organic solvent generally used in the art other than a straightener, a photoinitiator, and the above adhesion enhancer.
The straightening agent can include any straightening agent typically used in the art without limitation. For example, a polyacrylate polymer, a polyaminic acid, a polyamidene polymer or a polymer containing a cinnamate group can be used as a straightening agent. In the case of applying light alignment, the cinnamate group-containing polymer can be used.
The polymer used as the straightening agent may have a weight average molecular weight ranging from 10,000 to 500,000, but is not limited thereto.
The adhesion enhancer according to the present invention may be included in an amount of 0.1 to 20 parts by weight ("wt. parts") with respect to 100 parts by weight of the leveling agent. The adhesion can be effectively ensured within the above range. If an excessive amount of the reinforcing agent is added, the adhesion can be enhanced, however, when the above reinforcing agent is applied to the optical film, other physical properties can be destroyed.
The photoinitiator can include any photoinitiator that is widely used in the art without being limited thereto. For example, a triazine compound, an acetophenone compound, a diimidazole compound, an anthraquinone compound, a benzoin compound, a diphenyl ketone compound, a thioxanthone compound, an anthraquinone compound or the like can be used, but is not limited thereto.
The triazine compound may include, for example, 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine; 2,4-bis(trichloromethane) 6-(4-methoxynaphthyl)-1,3,5-triazine; 2,4-bis(trichloromethyl)-6-piperidin-1,3,5-triazine; 2,4-bis(trichloromethyl)-6-(4-methoxystyrile)-1,3,5-triazine; 2,4-bis(trichloromethyl)-6-[2-( 5-methylfuran-2-yl)vinyl]-1,3,5-triazine; 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)vinyl] -1,3,5-triazine; 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)vinyl]-1,3 , 5-triazine; 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)vinyl]-1,3,5-triazine, and the like .
The acetophenone compound may include, for example, diethoxyethyl benzene; 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzyl dimethyl ketal; 2-hydroxy-1- [4-(2-hydroxyethoxy)phenyl]-2-methylpropan-1-one; 1-hydroxycyclohexyl phenyl ketone; 2-methyl-1-(4-methylphenylthio) -2-morpholinepropan-1-one; 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)butan-1-one; 2-hydroxy-2-methyl-1 - oligomer of [4-(1-methylvinyl)phenyl]propan-1-one; 2-methyl-2-amino (4-morpholinylphenyl) ethyl-1-one; 2- Ethyl-2-amino(4-morpholinylphenyl)ethan-1-one; 2-propyl-2-amino (4-morpholinylphenyl)ethan-1-one; 2-butyl-2 -amino(4-morpholinylphenyl)ethan-1-one; 2-methyl-2-amino(4-morpholinylphenyl)propan-1-one; 2-methyl-2-amino group ( 4-morpholinylphenyl)butan-1-one; 2-ethyl-2-amino (4-morpholinylphenyl)propan-1-one; 2-ethyl-2-amino (4-morpholine) Phenyl)butan-1-one; 2-methyl-2-methylamino (4-morpholinylphenyl)propan-1-one; 2-methyl-2-dimethylamino (4-? Phenylphenyl)propan-1-one; 2-methyl-2-diethylamino (4-morpholinylphenyl)propan-1-one, and the like.
The diimidazole compound may include, for example, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyldiimidazole;2,2'-bis(2,3-diChlorophenyl)-4,4',5,5'-tetraphenyldiimidazole;2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetra(alkoxy)Phenyl)diimidazole;2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetrakis(trialkoxyphenyl)diimidazole; at 4,4',5, An imidazole compound having a phenyl group at the 5' position, which is substituted by an alkoxycarbonyl group, and the like. Among these, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyldiimidazole and/or 2,2'-bis (2,3) are preferably used. -Dichlorophenyl)-4,4',5,5'-tetraphenyldiimidazole.
The hydrazine compound may include, for example, 0-ethoxycarbonyl-α-oxyimino-1-phenylpropan-1-one.
The benzoin compound may include, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and the like.
The diphenyl ketone compound may include, for example, diphenyl ketone, methyl 0-benzylidene benzoate, 4-phenyldiphenyl ketone, 4-benzylidene-4'-methyldiphenyl sulphide. Ether, 3,3',4,4'-tetrakis(tert-butylperoxycarbonyl)diphenyl ketone, 2,4,6-trimethyldiphenyl ketone, or the like.
The thioxanthone compound may include, for example, 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthene Ketone, and so on.
The ruthenium compound may include, for example, 9,10-dimethoxyanthracene, 2-ethyl-9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 2-ethyl-9,10 - Diethoxy hydrazine, or the like.
Alternatively, 2,4,6-trimethylbenzimidyldiphenylphosphine oxide, 10-butyl-2-chloroacridone, 2-methylindole, benzyl, 9-10-phenanthrenequinone, A camphor quinone, a methylphenyl chlioxylate, a titanocene compound, a photopolymerization initiator having a transferable chain group, and the like are disclosed in Japanese Unexamined Patent Publication No. Publication No. No. 2002-544205.
In another aspect of the composition for forming a alignment layer in accordance with the present invention, the composition may not include a photoinitiator. The photoinitiator has the advantage of allowing the photo-alignment agent to easily photopolymerize. However, in the case of excessive use of a photoinitiator, it can act as an impurity to reduce the alignment activity and disrupt the orientation of the liquid crystal, with the occurrence of light leakage during cross-polarization. Or, after photocuring, the initiator is sublimed and the mask can be contaminated. Alternatively, if the intensity of the reaction wavelength of the initiator during exposure is substantially higher than the intensity of the reaction wavelength of the light straightening agent, the linear velocity should be reduced to perform optical alignment, thus causing counter effects such as reduced productivity. In view of the above, the inventive composition for forming the alignment layer may or may not include a very small amount of photoinitiator.
The organic solvent may include any organic solvent widely used in the art, without being limited thereto. More particularly, ethylene glycol monoalkyl ethers, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, etc.; diethylene glycol dioxane Ether ether, such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol dipropyl ether, diethylene glycol butyl ether, etc.; Ethyl acetate, such as cellosolve methyl acetate, cellosolve ethyl acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoether acetate, etc.; alkyl glycol alkyl ether acetate, For example, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, butyl methoxyacetate, amyl methoxy acetate, etc.; propylene glycol monoalkyl ether, such as propylene glycol monomethyl ether, Propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, etc.; propylene glycol dialkyl ether, such as propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol ethyl methyl ether, propylene glycol dipropyl ether, propylene glycol propyl methyl ether, Propylene glycol ethyl propyl ether, etc.; propylene glycol alkyl ether propionate, such as propylene glycol methyl ether propionate, Glycol ether propionate, propylene glycol propyl ether propionate, propylene glycol butyl ether propionate, etc.; butanediol monoalkyl ethers, such as methoxybutanol, ethoxybutanol, propoxybutanol Butoxybutanol, etc.; butanediol monoalkyl ether acetate, such as butyl methoxyacetate, butyl ethoxyacetate, butyl propyl acetate, butyl butoxyacetate, etc. Et.; butanediol monoalkyl ether propionate, such as butyl methoxypropionate, butyl ethoxypropionate, butyl propoxy propylate, butyl butoxypropionate, etc.; a propylene glycol dialkyl ether such as dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol methyl ether, or the like; an aromatic hydrocarbon such as benzene, toluene, xylene, mesitylene, etc.; a ketone, For example, methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, cyclohexanone, etc.; alcohols such as ethanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, glycerol , etc.; esters such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, 2 -ethyl hydroxy-2-methylpropionate, methyl hydroxyacetate, ethyl hydroxyacetate, butyl hydroxyacetate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, methyl 3-hydroxypropionate , 3-hydroxypropionic acid ethyl ester, 3-hydroxypropionic acid propyl ester, 3-hydroxypropionic acid butyl ester, 2-hydroxy-3-methylbutyric acid methyl ester, methyl methoxyacetate, methoxyacetic acid Ester, propyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, propyl ethoxyacetate, butyl ethoxyacetate, methyl propyl acetate , propoxyacetic acid ethyl ester, propoxy propyl acetate, butyl butyl acetate, methyl butoxyacetate, ethyl butoxyacetate, propyl butoxyacetate, butyl butoxyacetate, Methyl 2-methoxypropionate, ethyl 2-methoxypropionate, propyl 2-methoxypropionate, butyl 2-methoxypropionate, methyl 2-ethoxypropionate, Ethyl 2-ethoxypropionate, propyl 2-ethoxypropionate, butyl 2-ethoxypropionate, methyl 2-butoxypropionate, ethyl 2-butoxypropionate, Propyl 2-butoxypropionate, butyl 2-butoxypropionate, methyl 3-methoxypropionate, Ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, Propyl 3-ethoxypropionate, butyl 3-ethoxypropionate, methyl 3-propoxypropionate, ethyl 3-propoxypropionate, propyl 3-propoxypropionate, Butyl 3-propoxypropionate, methyl 3-butoxypropionate, ethyl 3-butoxypropionate, propyl 3-butoxypropionate, butyl 3-butoxypropionate, Etc.; a cyclic ether such as tetrahydrofuran, pyran, and the like; a cyclic ester such as g-butyrolactone, and the like may be used singly or in combination of at least two or more thereof.
The inventive composition for forming the alignment layer can optionally include additives such as fillers, hardeners, leveling agents, adhesion promoters, antioxidants, UV absorbers, anticoagulants, chain transfer agents, and the like. Wait.
In the polarizing plate 300 of the present invention, the liquid crystal layer 330 can be formed by curing the liquid crystal compound. The liquid crystal layer 330 according to the present invention has a reactive group, and the reactive group may include, for example, a carbon-carbon unsaturated bond, a hydroxyl group, an epoxy group, a cyano group, and the like. It is preferred to use a carbon-carbon unsaturated bond. More particularly, the carbon-carbon unsaturated bond may include, for example, a carbon-carbon unsaturated bond contained in an acryloyloxy group, a cyanoacrylate, an allyl group, a cinnamate salt or an allyloxy group. .
Therefore, any substrate material having a reactive group among the conventional liquid crystal compounds used in the art can be used in the present invention without limitation, and, although any conventional liquid crystal compound is not inherently having such a property as described above The reactive group can be used in the present invention without limitation, as long as it has the reactive group at its end via pretreatment known in the art.
In addition to the above liquid crystal compound, the liquid crystal layer 330 of the present invention can be prepared by hardening a composition including a polymerization initiator and an organic solvent, wherein the polymerization initiator can be a photopolymerization initiator widely used in the art or Thermal polymerization initiator. In particular, the photopolymerization initiator can be any of the above-exemplified photoinitiators. The organic solvent used herein may also be suitably selected from the above organic solvents.
The liquid crystal layer 330 may have a retardation effect depending on the orientation of the liquid crystal. According to the present invention, the orientation of the liquid crystal layer 330 may be the same or include first and second patterns having different optical axis directions. When the first and second patterns of the liquid crystal layer having different optical axis directions are provided, the different optical axes may be substantially at right angles to each other.
Regarding the polarizing plate 300 of the present invention, the alignment layer 320 can react with a reactive group on the surface of the transparent substrate film 310 and a reactive group of the liquid crystal compound exposed on the surface of the photocurable liquid crystal layer 330 to form a chemical bond. Herein, the transparent substrate film 310 and the reactive groups exposed on the surface of the liquid crystal layer 330 may be the same or different from each other.
As a specific example of the above chemical bond, an amine can be formed by reacting an isocyanate end of the adhesion enhancer with a hydroxyl group, a thiol, a carboxyl group, an amine group, an epoxy group or a cyano group in the transparent substrate film 310 or the liquid crystal layer 330. Formate bond.
The formation of a carbamate linkage via reaction of an isocyanate group with a hydroxyl, thiol, carboxyl, amine, epoxy or cyano group can be represented by the following reaction scheme. For reference, the cyano group can be modified to an amine or a carboxyl group by preheating it with H2O before it is reacted with the isocyanate group.
[Reaction Scheme 1]


[Reaction Scheme 2]

[Reaction Scheme 3]

[Reaction Scheme 4]


[Reaction Scheme 5]

[Reaction Scheme 6]

As another example of a chemical bond, carbon can be formed by reacting an adhesion enhancer (meth) acrylate end with a (meth) acrylate group or a carbon-carbon unsaturated bond of the transparent substrate film 310 or the liquid crystal layer 330. - Carbon saturation bond.
As a further example of a chemical bond, a thiol-vinyl bond can be formed by reacting a (meth) acrylate end of an adhesion enhancer with a thiol group of the transparent substrate film 310.
The alignment layer 320 of the present invention can be combined with the transparent substrate film 310 and the photocurable liquid crystal layer 330 to have a high bonding force via a chemical bond such as the above-described urethane bond, carbon-carbon saturated bond or thiol-vinyl bond. .
Regarding the inventive polarizing plate 300, the first bonding layer 340 can function to directly bond the liquid crystal layer 330 to the polarizer 350. Therefore, the inventive polarizing plate 300 can have a structure in which the retardation film is integrated with the polarizing plate.
The first bonding layer 340 is preferably prepared from an aqueous adhesive or a photocurable adhesive.
The aqueous adhesive may contain water as a solvent, and thus is more environmentally friendly than any adhesive using an organic solvent. The aqueous adhesive used in the present invention can be prepared without using any aqueous adhesive used in the art without limitation.
The photocurable adhesive means an adhesive which is hardened by light irradiation such as UV light. Since the photocurable adhesive does not require an additional drying process after photocuring, a simple process can be used while increasing productivity. The photocurable adhesive used in the present invention can be prepared using any photocurable adhesive used in the art without limitation.
The binder component in the adhesive can include a polymer having at least one functional group selected from the group consisting of epoxy, acrylate, and isocyanate groups. In this regard, in the case where the binder component in the adhesive contains an epoxy group, if the liquid crystal compound of the liquid crystal layer 330 has an epoxy group as a reactive group, the epoxy group in the first binder layer 340 can be The epoxy group in the liquid crystal layer 330 reacts to form a carbon-carbon saturated bond.
The adhesive layer 340 generally has a thickness of 20 μm or less, preferably 10 μm or less, and more preferably 5 μm or less. When the bonding layer is thick, the reaction rate of the adhesive composition is lowered, and the moist heat resistance of the polarizing plate tends to be broken.
The bonding layer 340 may be placed on the attachment surface of the polarizer 350 or formed on the liquid crystal layer 330. The coating of the first bonding layer 340 can be performed using, for example, a doctor blade, a wire ingot, a die coater, a comma coater, a gravure coater, or other means generally known in the art, without Its limits. At the same time, a continuous feed polarizer 350 and a retardation film provided with the liquid crystal layer 330 may be adopted, such that the adhesion surface of the polarizer and the retardation film are on the inner side, and the process of the adhesive composition flowing therebetween . Each coating process has an optimum viscosity range, and therefore, it is proposed to use a solvent to appropriately adjust the viscosity of the bonding layer as a useful technique. In this case, the solvent is preferably a solvent which advantageously dissolves the first adhesive layer 340 therein without destroying the optical properties of the polarizer, but is not particularly limited to its type. For example, depending on the type of the adhesive, water or an organic solvent such as a hydrocarbon such as toluene may be used as a representative example, an ester including ethyl acetate as a representative example, or the like.
Regarding the polarizing plate 300 of the present invention, the polarizer 350 can be any polarizer used in the art without limitation. Conventional polarizers include stretched polyvinyl alcohol films having a two-color dye adsorbed and oriented thereon.
The polyvinyl alcohol resin forming the polarizer can be produced by saponification of a polyvinyl acetate resin. Examples of the polyvinyl acetate resin may include polyvinyl acetate as a homopolymer of vinyl acetate and, in addition, a copolymer of vinyl acetate and a monomer copolymerizable with vinyl acetate. Such a monomer copolymerizable with vinyl acetate may include, for example, an unsaturated carboxylic acid, an unsaturated sulfonic acid, an olefin, a vinyl ether, an ammonium group-containing acroleinamide monomer, and the like. The polyvinyl alcohol resin may be a modified resin including, for example, an aldehyde-modified polyvinyl formal or polyvinyl acetal, and the like. The degree of saponification of the polyvinyl alcohol resin generally ranges from 85 to 100 mol%, and preferably 98 mol% or more. Further, the degree of polymerization of the polyvinyl alcohol resin generally ranges from 1,000 to 10,000, and preferably from 1,500 to 5,000.
The polyvinyl alcohol resin can be formed into a film for use as a polarizer disk film. The method of forming the polyvinyl alcohol resin film is not particularly limited, but may include any method known in the art. The thickness of the disc film is not particularly limited, but may range from 10 to 150 μm.
The polarizer can be prepared by the above process: uniaxially stretching a polyvinyl alcohol film; dyeing the film with a two-color dye to guide dye adsorption on the film; treating the adsorbed film with a boric acid solution; and washing and drying the film . The polarizer prepared as described above may have a thickness ranging from 5 to 40 μm.
Regarding the polarizing plate 300 of the present invention, the second bonding layer 360 is a layer that bonds the polarizer 350 to the transparent substrate film or the retardation film 370, and may include any adhesive used in the art without limitation. For example, an adhesive used in the first adhesive layer 340 may also be employed for the second adhesive layer. Further, other organic adhesives may be used, but are not limited thereto.
Regarding the polarizing plate 300 of the present invention, the transparent substrate film or retardation film 370 may be a layer having a protective function of the polarizer 350 and optionally having a retarding effect. The transparent substrate film and retardation film may include any transparent substrate film and retardation film widely used in the art without limitation.
The polarizing plate 300 of the present invention can be usefully used in an image display device. Such an image display device is not particularly limited, but may include, for example, a liquid crystal display device for realizing a stereoscopic image, a transflective LCD device, an organic EL display device, and the like.
The invention will be described more particularly hereinafter with reference to examples and comparative examples. However, it will be apparent to those skilled in the art that various modifications and changes in the particular embodiments are possible, and the scope of the invention is not limited to the specific embodiments described below. The present invention has been described in terms of a preferred embodiment of the present invention, in which the present invention will be described more fully and specifically to those skilled in the art.
example
Examples 1 to 14 and Comparative Examples 1 and 2
<Preparation of a composition for forming a straightening layer>
According to the basic composition listed in Table 1 below, a light straightening agent, an adhesion enhancer, a photoinitiator (Irgacure 907, manufactured by BASF, Co.), and an organic solvent (toluene) were mixed together to prepare each. The composition (unit: g) used to form the alignment layer.

Table 1


<Formation of polarizing plate>
For examples 1 through 7:
According to the examples 1 to 7, each of the compositions for forming the alignment layer prepared in the above Preparation Examples 1 to 7 was applied to a TAC film manufactured by Fuji Co., and the film was dried at 100 ° C for 1 minute. Thereafter, the treated film is subjected to first and second exposures, respectively, to form a alignment layer having patterns A and B having a hydroxyl group introduced on the surface thereof via saponification. A photocurable liquid crystal composition (RMS) including a liquid crystal compound is applied to a alignment layer formed thereon, the liquid crystal compound having a carbon-carbon unsaturated bond at its end, and then the coated film is dried at 60 ° C. Minutes to prepare a retardation film.
Next, after the adhesive was applied to another TAC film manufactured by Fuji Co., a polyvinyl alcohol polarizer was attached to the film, and an aqueous adhesive was applied to the polarizer.
Thereafter, the retardation film is laminated on the aqueous adhesive layer to enable the liquid crystal layer of the retardation film to contact the aqueous adhesive layer, followed by exposure to induce a curing reaction, and then dry the exposed laminate, thereby A polarizing plate incorporating an retardation film is formed.
For examples 8 through 14:
According to Examples 8 to 14, each of the compositions for forming the alignment layers prepared in the above Preparation Examples 1 to 7 was applied to a TAC film manufactured by Fuji Co., and the film was dried at 100 ° C for 1 minute. Thereafter, the treated film is subjected to first and second exposures, respectively, to form a alignment layer having patterns A and B having a hydroxyl group introduced on the surface thereof via saponification. A photocurable liquid crystal composition (RMS) including a liquid crystal compound is applied to a alignment layer formed thereon, the liquid crystal compound having a carbon-carbon unsaturated bond at its end, and then the coated film is dried at 60 ° C. Minutes to prepare a retardation film.
Next, after the adhesive was applied to another TAC film manufactured by Fuji Co., a polyvinyl alcohol polarizer was attached to the film, and a photocurable adhesive was applied to the polarizer.
Thereafter, the retardation film is laminated on the photocurable adhesive layer to enable the liquid crystal layer of the retardation film to contact the photocurable adhesive layer, followed by exposure to induce a curing reaction, and then to dry the exposed laminate. Thus, a polarizing plate incorporating a retardation film is formed.
For comparative examples 1 and 2:
Each retardation film was prepared by the same procedure as described in Examples 1 to 7 except that a bonding layer was provided on the liquid crystal layer of the prepared retardation film (see Fig. 1).
Similarly, a polarizing film was prepared by the same procedure as described in Examples 1 to 7, except that the TAC film was attached to the aqueous bonding layer on the polarizer.
Next, the formed polarizing film was attached to the adhesive layer of the prepared retardation film, thus producing each polarizing plate.
Experimental example
<directional angle>
The orientation angle of the pattern "A" among the two patterns A and B of the polarizing plate formed above was measured using a WPA-100L device (Lukeo Com. or Photonic Lattice, Inc.), and the results are shown below:
◎: 45° ± 3 (for A pattern), 135 ° ± 3 (for B pattern)
○: less than 45° ± 6 (for A pattern), less than 135° ± 6 (for B pattern)
×: not less than 45 ° ± 6 (for A pattern), not less than 135 ° ± 6 (for B pattern)
<delay effect>
Rr; retardation effect of the polarizing plate formed in Comparative Example 1
Rs; retardation effect of the polarizing plate of the invention
◎: 0.97 < Rs/Rr < 1.03
○: 0.95 < Rs/Rr < 0.97 or 1.03 < Rs/Rr < 1.05
△: 0.90 < Rs/Rr < 0.95 or 1.05 < Rs/Rr < 1.1
×: Rs/Rr of not less than 1.1, or Rs/Rr of not more than 0.90
<Alignment layer and bonding force between liquid crystal layers>
The surface tear on the pattern of the prepared pattern was evaluated via an optical microscope, and the results are shown in Table 2 below.
◎: no surface tear was observed on the pattern
○: 1 to 3 surface tears on the pattern
△: 4 to 8 surface tears on the pattern
×: There are more than 8 surface tears on the pattern
<transmittance>
For each of the polarizing plates formed as described above, a transmittance (%) at 400 nm was determined using a microscope spectrometer (OSP-SP200; manufactured by Olympus Co.). It is more preferable when the transmittance is close to 100%.
◎: transmittance of 99.5% or higher
○: 99% transmittance is at least 99.5%
△: 98% transmittance is at least 99%
×: less than 98% transmittance
<Waterproof>
For each polarizing plate at 23 ° C at 55% relative humidity for 24 hours, a hot water resistance test (hot water immersion test) was performed to evaluate water repellency.
First, after the polarizing plate is cut into strips having a size of 5 cm × 2 cm (in the extending direction of the polarizer) along the absorption axis of the polarizing plate, the cut strips are used as samples and are accurately determined. The sample size in the long side direction.
In this regard, throughout the sample, the sample uniformly exhibited a particular color due to the iodine absorbed on the polarizer.
Fig. 3 schematically illustrates a method of evaluating water repellency, in which (A) represents the sample 1 before being immersed in hot water, and (B) represents the sample 1 after it is immersed in hot water. As shown in Fig. 3(A), the short side of the sample was clamped using the clip 5, and about 80% of the length direction was immersed in a water bath of 60 ° C and maintained therein for 4 hours. Thereafter, the sample was taken out of the water bath and moisture was removed therefrom.
The polarizer 4 of the polarizing plate contracts due to the immersion of hot water. The degree of contraction of the polarizer 4 is determined by measuring the distance from the one end 1a (one end of the transparent substrate film) at the center of the short side of the sample 1 to the end of the contracting polarizer 4, and the determined value is defined as the contraction length. .
Further, as shown in Fig. 3(B), since the polarizer 4 positioned at the center of the polarizing plate has been shrunk by the hot water, the region 2 where the polarizer 4 does not exist is formed in the transparent substrate film.
At the same time, by immersion in hot water, iodine is ejected from the periphery of the polarizer 4 which is in contact with the hot water, and the decolorizing portion 3 appears on the periphery of the sample.
The degree of discoloration is determined by measuring the distance from one end of the polarizer 4 contracted at the center of the short side of the sample 1 to the region in which the specific color of the polarizing plate is still, and the determined value is defined as the length without iodine. . The sum of the shrinkage length and the length of the iodine-free is defined as the total erosion length "X". That is, the total erosion length "X" means the distance from the end 1a (transparent substrate film end) of the sample 1 at the center of the short side of the sample 1 to the region in which the specific color of the polarizing plate is still.
It is confirmed that as the shrinkage length, the iodine-free length, and the total erosion length "X" decrease, the adhesion (water repellency) in the presence of water is improved. In addition, depending on the total erosion length "X", the results can be evaluated by the following four stages:
◎: Total erosion length less than 2 mm X
○: Total erosion length X ranging from 2 mm to less than 3 mm
△: total erosion length in the range of 3 mm to less than 5 mm X
×: total erosion length X of 5 mm or more
<degree of polarization>
(A) Orthogonal polarized light transmittance TD(λ), parallel transmittance MD(λ)
For the measurement light-emitting portion of the sample chamber connected to the "V-7100" type visible spectrometer manufactured by Nippon Bunko Co. Ltd., a Glan-Taylor prism was mounted to emit polarized light in a predetermined oscillation direction.
Placing a polarizing plate sample on the light path of the emitted and polarized light such that the polarized light is incident perpendicularly into the sample and is set such that the polarized light has a minimum transmittance and determines each wavelength λ in the visible range Transmittance. The determined value is defined as the transmittance of linearly polarized light in the absorption axis direction, that is, the orthogonal polarization transmittance TD(λ).
Subsequently, the above sample is rotated by 90 in the sample plane, and the transmittance of each wavelength λ in the visible light range is determined. The determined value is defined as the transmittance of linearly polarized light in the direction of the transmission axis, that is, the parallel transmittance MD(λ).
(B) Polarization luminescence factor correction degree Py
Using the TD(λ) and MD(λ) determined in the above (A), the degree of polarization Py(λ) at each wavelength is calculated by the following mathematical equation.


After that, according to JIS Z 8701, the above-calculated polarization degree Py(λ) is subjected to weight average calculation using the stimulation value in the C-light source 2° field of view, and the polarization luminescence factor correction degree Py is obtained. This result is evaluated by the following three stages.
○: Pym 99.996% or more
△: Py greater than 99.993% and less than 99.996%
×: 99.993% or less of Py

Table 2

As shown in Table 2, it is considered that each of the polarizing plates in the inventive example exhibits substantially the same or similar orientation angle, retardation performance, water repellency, and polarization as the polarizing plate in the comparative example. degree.
However, it can be seen that, in the inventive example, each of the polarizing plates incorporating the retardation film has excellent interlayer bonding force between the alignment layer and the liquid crystal layer, compared to the polarizing plate in the comparative example. .
Further, it can be seen that the polarizing plate of the present invention has much higher transmittance than the polarizing plate in the comparative example. It is considered that, unlike the polarizing plate in the comparative example, these results were obtained because each of the polarizing plates in the inventive example did not have a transparent substrate film in the plate.

1. . . sample

1a. . . The end of the sample short side center

2. . . The polarizer does not exist in the area between the transparent substrate films

3. . . Decolorizing part around the polarizer

4. . . Shrinking polarizer

5. . . Clip

100,370. . . Delay film

110. . . Transparent substrate

120,320. . . Straight layer

130,330. . . Cured liquid crystal layer

140,220,240,340,360. . . Bonding layer

200. . . Upper polarizer

210,310. . . Transparent substrate film

230,350. . . Polarizer

250. . . Transparent substrate film / retardation film

300. . . Polarizer

X. . . Total erosion length

300. . . Polarizer

310. . . Transparent substrate film

320. . . Straight layer

330. . . Cured liquid crystal layer

340,360. . . Bonding layer

350. . . Polarizer

370. . . Delay film

Claims (20)

A polarizing plate prepared from a composition for forming a straightening layer, comprising:
a polarizer layer;
a bonding layer formed on at least one side of the polarizer layer; and a retardation film having a structure in which a liquid crystal layer, a alignment layer, and a substrate are laminated in this order, wherein the liquid crystal a layer attached to the bonding layer, and wherein the alignment layer comprises an adhesion enhancer having an isocyanate group and a (meth) acrylate group at a terminal thereof, and wherein the isocyanate group and The (meth) acrylate groups are respectively bonded to a reactive group on one surface of the substrate and a reactive group of a liquid crystal compound in the liquid crystal layer. The polarizing plate of claim 1, wherein the adhesion enhancer is at least one selected from the group consisting of compounds represented by the following formulas 1 to 4:
[Molecular Formula 1]

(wherein R1 and R2 are each independently hydrogen or methyl;
R 3 and R 7 are each independently an alkylene group having 1 to 10 carbon atoms which are substituted or unsubstituted by a group selected from the group consisting of a ketone, an ester, and a thiol group;
R4 and R6 are each independently an alkylene group having 1 to 10 carbon atoms which are substituted or unsubstituted by a group selected from the group consisting of a guanamine, a ketone, an ester, and a thiol group;
R5 is an alkylene group having 1 to 10 carbon atoms which is substituted or unsubstituted with an alkoxy group having 1 to 8 carbon atoms. ),
[Molecular Formula 2]

(wherein R7 and R8 are each independently hydrogen or methyl;
R9 and R11 are each independently an alkylene group having 1 to 10 carbon atoms which are substituted or unsubstituted by a group selected from the group consisting of a ketone, an ester, and a thiol group;
R10 is (a) Or (b) Wherein E1 and E3 are each independently an alkyl group having 1 to 10 carbon atoms, which is substituted or unsubstituted with an alkoxy group having 1 to 8 carbon atoms, or has 1 to 8 The alkoxy group of one carbon atom, and E2 is an alkylene group having 1 to 10 carbon atoms, which is substituted or unsubstituted by an alkoxy group having 1 to 8 carbon atoms. ),
[Formula 3]

(wherein R12 is hydrogen or methyl,
R13 is an alkylene group having 1 to 10 carbon atoms which is substituted or unsubstituted by a group selected from the group consisting of a ketone, an ester, and a thiol group. )
[Molecular Formula 4]

(wherein R14 is hydrogen or methyl,
R15 is an alkylene group having 1 to 10 carbon atoms which is substituted or unsubstituted by a group selected from the group consisting of a ketone, an ester, and a thiol group. ) The polarizing plate according to claim 2, wherein the adhesion enhancer is a mixture of at least one of a compound represented by the formula 1 and a compound represented by the formulae 2 to 4. The polarizing plate of claim 1, wherein the alignment layer comprises a polymer having a cinnamate group as a light straightening agent. The polarizing plate of claim 4, wherein the adhesion enhancer is included in an amount of 0.1 to 20 parts by weight relative to 100 parts by weight of the optical straightening agent. The polarizing plate of claim 1, wherein the reactive group on the surface of the substrate is selected from the group consisting of a hydroxyl group, a thiol, a carboxyl group, a (meth) acrylate, an amine, and an epoxy group. At least one of the groups. The polarizing plate of claim 1, wherein the substrate is subjected to at least one selected from the group consisting of saponification, primer treatment, corona discharge, plasma treatment, and a coating process. Surface treatment. The polarizing plate of claim 7, wherein the plasma treatment is selected from the group consisting of remote plasma treatment, direct plasma treatment, and monomer plasma treatment. The polarizing plate of claim 1, wherein the alignment layer is bonded to the substrate via a urethane bond, a thiol-vinyl bond or a carbon-carbon saturation bond. The polarizing plate according to claim 9, wherein the urethane bond is an isocyanate group of the compound represented by any one of Formulas 1 to 4 in the alignment layer. The substrate is formed by reacting a monohydroxy group, a thiol, a carboxyl group, an amine or an epoxy group. The polarizing plate according to claim 9, wherein the thiol-vinyl bond is a (meth) acrylate group of a compound represented by any one of Formulas 1 to 4 in the alignment layer. The group is formed by reacting with a thiol group of the substrate. The polarizing plate according to claim 9, wherein the carbon-carbon saturated bond is a (meth) acrylate group represented by any one of the molecular formulas 1 to 4 in the alignment layer. A (meth) acrylate group of the substrate is formed by reaction. The polarizing plate of claim 1, wherein the liquid crystal layer is prepared using a liquid crystal compound having a carbon-carbon unsaturated bond, a monohydroxy group, an epoxy group or a cyano group. The polarizing plate of claim 1, wherein the alignment layer is bonded to the liquid crystal layer via a urethane bond or a carbon-carbon saturation bond. The polarizing plate according to claim 14, wherein the urethane bond is an isocyanate group of the compound represented by any one of Formulas 1 to 4 in the alignment layer. The liquid crystal layer is formed by reacting a monohydroxy group, an epoxy group or a cyano group of the liquid crystal compound. The polarizing plate according to claim 14, wherein the carbon-carbon saturated bond is a (meth) acrylate group of a compound represented by any one of Formulas 1 to 4 in the alignment layer. The group is formed by reacting with a carbon-carbon unsaturated bond of the liquid crystal compound in the liquid crystal layer. The polarizing plate of claim 1, wherein the adhesive layer is prepared using an aqueous adhesive or a photocurable adhesive. The polarizing plate of claim 1, wherein the bonding layer and the liquid crystal layer are bonded via a carbon-carbon saturation bond. The polarizing plate of claim 1, wherein the retardation film is a patterned retardation film provided with the first and second patterns, the first and second patterns having optical axes different from each other. An image display device comprising the polarizing plate according to any one of claims 1 to 19.