WO2014204205A1 - Polarizing plate and image display apparatus comprising same - Google Patents

Abstract

The present invention relates to a polarizing plate having, in the following order, an adhesive layer, a primer layer and a polyethylene terephthalate film provided on at least one side of a polarizer. In the present invention, the adhesive layer is formed by an active energy ray-curable adhesive comprising: a first epoxy compound in which the glass transition temperature of a homopolymer is 120 ℃ or higher; a second epoxy compound in which the glass transition temperature of a homopolymer is 60 ℃ or lower; and a cationic photopolymerization initiator, and the primer layer is formed by a primer composition comprising: at least one binder resin selected from the group consisting of polyester and a polyvinyl alcohol-based resin; and at least one cross-linking agent selected from the group consisting of an acryl-based cross-linking agent, an epoxy-based cross-linking agent and a polyvinyl alcohol-based cross-linking agent.

Description

Polarizing plate and image display device including the same

The present invention relates to a polarizing plate and an image display device including the same, and more particularly, to a polarizing plate having a polyethylene terephthalate film as a protective film on one surface of the polarizer and an image display device including the same.

Recently, liquid crystal displays have low power consumption, operate at low voltage, and are used in various display devices due to their light weight and thinness. The liquid crystal display device is composed of many materials such as a liquid crystal cell, a polarizing plate, a retardation film, a light collecting sheet, a diffusion film, a light guide plate, and a light reflection sheet. Therefore, improvement aimed at productivity, weight reduction, brightness improvement, etc. is actively performed by reducing the number of constituent films or making the thickness of a film or sheet thin.

The polarizing plate has been commonly used as a structure in which a protective film is laminated using one or both surfaces of a polarizer made of polyvinyl alcohol (hereinafter referred to as 'PVA')-based resin dyed with dichroic dye or iodine. Conventionally, a triacetyl cellulose (TAC) film has been mainly used as a polarizer protective film, but such a TAC film has a problem in that it is easily deformed in a high temperature and high humidity environment. Therefore, recently, protective films of various materials that can replace TAC films have been developed. For example, polyethylene terephthalate (PET), cycloolefin polymer (COP, cycloolefin polymer), acrylic film, etc. Or a mixed use has been proposed.

Among them, since the polyethylene terephthalate film is inexpensive and excellent in transparency, research on the technology of using the polyethylene terephthalate film as a protective film is being actively conducted.

Korean Patent Publication No. 2011-0075998, 2010-0068178, etc. disclose a polarizing plate in which an aqueous adhesive layer and an easily adhesive layer are interposed between a polarizer and a polyethylene terephthalate film. However, since these conventional techniques use water-based adhesives, there is a problem in that durability between the polarizer and the polyethylene terephthalate film is not sufficient, resulting in poor durability. In addition, although polyethylene terephthalate film is inexpensive but low in moisture permeability and optical properties, polyethylene terephthalate is used on one side when manufacturing a polarizing plate, and another type of polymer film having excellent properties such as optical properties and moisture permeability on the other side It is common to use. By the way, when the water-based adhesive is used as the adhesive in the polarizing plate using a different type of polymer film on both sides of the polarizer, due to the difference in moisture transmittance between the polyethylene terephthalate film and the other type of polymer film in the drying process for curing the adhesive There is a problem that a difference in drying efficiency occurs and as a result, the curl of the polarizing plate is deepened. If curl is generated in the polarizing plate, it is difficult to attach during the lamination process of attaching the polarizing plate to the image display device, and a problem such as an increase in the defective rate due to the inflow of foreign matters occurs. Further, even after the image display device is attached, poor contact with the liquid crystal panel or warpage of the liquid crystal panel is likely to occur due to the curling of the polarizing plate. Therefore, when mounted on the display device module, the contact with the module case occurs, causing a large stress. Therefore, light leakage or mura may occur, which may cause image defects.

Therefore, while using a polyethylene terephthalate film as a protective film, it is necessary to develop a polarizing plate excellent in optical characteristics and curl characteristics.

The present invention is to solve the above problems, to provide a polarizing plate that can implement excellent curl properties and optical properties while using a polyethylene terephthalate film.

To this end, in one aspect, the present invention is a polarizing plate provided with an adhesive layer, a primer layer and a polyethylene terephthalate film on at least one surface of the polarizer in this order, the adhesive layer is a first glass transition temperature of the homopolymer 120 ℃ or more It is formed by an active energy ray-curable adhesive comprising an epoxy compound, a second epoxy compound having a glass transition temperature of 60 ° C. or less, and a cationic photopolymerization initiator, and the primer layer is made of polyester and polyvinyl alcohol-based resin. Formed by a primer composition comprising at least one binder resin selected from the group and at least one crosslinking agent selected from the group consisting of an acrylic crosslinking agent, an epoxy crosslinking agent and a polyvinyl alcohol crosslinking agent. It provides a polarizing plate.

At this time, the active energy ray-curable adhesive is 100 parts by weight of the first epoxy compound having a glass transition temperature of the homopolymer of 120 ℃ or more, 30 to 100 parts by weight of the second epoxy compound having a glass transition temperature of the homopolymer of 60 ℃ or less and cationic light It may comprise 0.5 to 20 parts by weight of the polymerization initiator.

In addition, the polarizing plate may include a transparent polymer film selected from the group consisting of a triacetyl cellulose film, a cycloolefin polymer film, a polyester film, a polycarbonate film and an acrylic film on the other surface of the polarizer.

In another aspect, the present invention provides an image display device including the polarizing plate of the present invention as described above.

The polarizing plate according to the present invention minimizes curling even when using a polyethylene terephthalate film and a polymer film of a different kind from the polyethylene terephthalate film, and has excellent optical properties and durability.

In addition, the polarizing plate of the present invention improves the adhesive force between the polyethylene terephthalate film and the adhesive layer through a primer layer formed by the primer composition of a specific composition between the polyethylene terephthalate film and the adhesive layer, such as harsh conditions such as high temperature and high humidity. Even in the durability of the polarizing plate was to be maintained.

1 to 7 are photographs showing curl characteristics of the polarizing plates manufactured by Example 1 and Comparative Examples 1 to 6. FIG.

FIG. 8 is a photograph showing a state of a polarizing plate after immersing the polarizing plates prepared in Example 1 and Comparative Example 1 in water at 60 ° C. for 24 hours.

Hereinafter, preferred embodiments of the present invention will be described. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

The polarizing plate according to the present invention includes an adhesive layer, a primer layer and a polyethylene terephthalate film on at least one surface of the polarizer in this order, wherein the adhesive layer comprises a first epoxy compound having a glass transition temperature of the homopolymer of 120 ° C. or more, It is formed by an active energy ray-curable adhesive comprising a second epoxy compound having a glass transition temperature of homopolymer of 60 ° C. or less and a cationic photopolymerization initiator, and the primer layer is selected from the group consisting of polyester and polyvinyl alcohol resin. Formed by a primer composition comprising at least one binder resin and at least one crosslinking agent selected from the group consisting of an acrylic crosslinking agent, an epoxy crosslinking agent and a polyvinyl alcohol crosslinking agent. It is characterized by that.

Hereinafter, the components of the present invention will be described in more detail.

(1) polarizer

The polarizer which can be used in the present invention is not particularly limited, and polarizers generally used in the art, for example, polyvinyl alcohol-based film, partially formalized polyvinyl alcohol-based film, ethylene-vinyl acetate air Polyene type, such as a film which is made by adsorbing and stretching a polarizing material such as iodine or dichroic dye onto a hydrophilic polymer film such as a coalescing partial saponified film, orientating it in a predetermined direction, a dehydration treatment of polyvinyl alcohol or a dehydrochlorination treatment of polyvinyl chloride. Orientation film, etc., Preferably, the molecular chain containing an iodine-based compound or a dichroic polarizing material may be a polyvinyl alcohol polarizer oriented in a predetermined direction.

On the other hand, the polyvinyl alcohol-based polarizer may be produced by a polyvinyl alcohol-based polarizer manufacturing method well known in the art, the production method is not particularly limited. For example, the polarizer usable in the present invention may be prepared by impregnating an unstretched polyvinyl alcohol-based film in an aqueous solution of iodine and / or a dichroic dye, followed by dyeing, crosslinking, and stretching. After coating a vinyl alcohol-based resin or laminating or adhering a polyvinyl alcohol-based film on a polymer base film to form a film laminate, the film laminate is impregnated by immersion in an aqueous solution of iodine and / or dichroic dye, It may be prepared by crosslinking and stretching, and then separating the polymer base film.

Alternatively, the polyvinyl alcohol polarizer may be used by purchasing a commercially available product.

For convenience, in the present specification, the term 'polarizer' means a state in which the transparent polymer film is not attached to the polarizer, and the term 'polarizing plate' means a state in which the transparent polymer film is attached to the polarizer.

(2) protective film

In the present invention, a polyethylene terephthalate film is attached to at least one surface of the polarizer through an adhesive layer and a primer layer. Since the polyethylene terephthalate film has low moisture permeability and moisture content, when used as a polarizer protective film, not only improves the water resistance of the polarizing plate, but also has excellent resistance to heat and moisture, thereby maintaining excellent optical properties of the polarizing plate even at high temperature and high humidity. . In addition, since the polyethylene terephthalate film is cheaper to produce than other transparent polymer films, there is an advantage that the manufacturing cost of the polarizing plate can be lowered when it is used.

Meanwhile, the polyethylene terephthalate film usable in the present invention means a film formed of polyethylene terephthalate resin, wherein the polyethylene terephthalate resin is a resin in which 50 mol% or more of all the repeating units are ethylene terephthalate units. It is a concept including a film made of a resin containing a structural unit derived from other copolymerization components in addition to the ethylene terephthalate unit. In this case, as other copolymerization components, isophthalic acid, p-β-oxyethoxybenzoic acid, 4,4'-dicarboxydiphenyl, 4,4'-dicarboxybenzophenone, bis (4-carboxyphenyl) ethane, adipic Dicarboxylic acid components such as acid, sebacic acid, 5-sodium sulfoisophthalic acid and 1,4-dicarboxycyclohexane; And diol components such as propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like. Such dicarboxylic acid component and diol component can be used in combination of 2 or more type as needed. Moreover, oxycarboxylic acid, such as p-oxybenzoic acid, can also be used together with the said carboxylic acid component and diol component. As other copolymerization components, dicarboxylic acid components and / or diol components containing small amounts of amide bonds, urethane bonds, ether bonds, carbonate bonds and the like may be used.

The polyethylene terephthalate film used in the present invention may be prepared according to a method for producing a polyethylene terephthalate film well known in the art, or a commercially available polyethylene terephthalate film may be purchased.

On the other hand, the polyethylene terephthalate film usable in the present invention is not limited thereto, but, for example, water vapor transmission rate (WVTR) is 100 g / m ² · day or less, preferably 10 to 50 g / m ² · day, the moisture content is 1% by weight or less, preferably 0.1 to 0.6% by weight. It is because the water resistance and the durability improvement effect under high temperature, high humidity appear more when water vapor transmission rate and moisture content rate satisfy | fill the said numerical value.

In addition, the polyethylene terephthalate film usable in the present invention is not limited thereto, but may be a film having a low refractive index layer formed of a material having a refractive index of about 1.4 to 1.5 on at least one surface thereof. Generally, the polyethylene terephthalate film has a refractive index of 1.65, which is relatively higher than that of a TAC film. When applied as a polarizing plate protective film, light reflection is increased on the surface of the protective film, and a single transmittance of about 1% is higher than that of the polarizing plate using TAC film. There was a tendency to decrease. However, according to the researches of the present inventors, when using a polyethylene terephthalate film having a low refractive index layer, it is possible to prevent a decrease in the unitary transmittance of the polarizing plate after the production of the polarizing plate.

In this case, the low refractive index layer may be formed on one side or both sides of the polyethylene terephthalate film, preferably may be formed on the opposite side of the surface on which the primer layer is formed.

In addition, the low refractive index layer may be formed by a resin composition in which a low refractive index material is mixed with a polymer resin having a low refractive index. In this case, as the polymer resin, for example, an acrylic resin may be used, and the low refractive index may be used. Materials include 1,1,1-trifluoroethane, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE, Teflon) hydrofluoro ether, hydrochloro fluorocarbons, fluorocarbons, perfluorocarbons, Fluoro-based compounds such as perfluoropolyether, Perfluorooctanoic acid (PFOA), Perfluorooctane sulfonate (PFOS), perfluoroalkoxy fluoropolymer, or silica-based compounds may be used. have.

On the other hand, the total refractive index of the polyethylene terephthalate film is about 1.48 to 1.55, preferably about 1.50 to 1.53. In this case, the total refractive index means not only the refractive index of the single polyethylene terephthalate film, but also the effective refractive index of the polyethylene terephthalate film including other functional coating layers. For example, in the case of the polyethylene terephthalate film having the low refractive index layer described above, the effective refractive index of the low refractive index layer and the polyethylene terephthalate film, which is a functional coating layer, is the total refractive index. When the total refractive index of the polyethylene terephthalate film satisfies the above range, the difference in refractive index between the laminated films is reduced, thereby reducing the Fresnel reflection between the layers to prevent a decrease in transmittance of the polarizing plate alone, and to the high refractive index of the polyethylene terephthalate film itself. Rainbow phenomenon due to interference effect can be minimized.

Meanwhile, in the polarizing plate of the present invention, a polyethylene terephthalate film may be attached to both sides of the polarizer, a polyethylene terephthalate film may be attached to one surface of the polarizer, and a transparent polymer film other than the polyethylene terephthalate film may be attached to the other surface of the polarizer. have. In this case, the transparent polymer film attached to the other surface of the polarizer is a polarizer protective film or a compensation film for compensating the optical characteristics of the polarizer, and the material thereof is not particularly limited, and a polymer film known in the art may be used. More specifically, although not limited thereto, the transparent polymer film attached to the other surface is preferably selected from the group consisting of a triacetyl cellulose film, a cycloolefin polymer film, a polyester film, a polycarbonate film, and an acrylic film. . On the other hand, the transparent polymer film attached to the other surface may have optically isotropic or anisotropic, for example, having a phase difference value that can cancel the optical anisotropy of the polyethylene terephthalate film, or with a polyethylene terephthalate film It may have a suitable phase difference value that can compensate for the viewing angle characteristics of the liquid crystal display device applied in combination.

Meanwhile, the polyethylene terephthalate film and the transparent polymer film may be subjected to a surface treatment for improving adhesion when necessary, for example, selected from the group consisting of alkali treatment, corona treatment, and plasma treatment on at least one surface of the optical film. At least one surface treatment may be performed.

(3) adhesive layer

In the present invention, the polarizer and the polyethylene terephthalate film are attached by an active energy ray curable adhesive. In this case, the active energy ray-curable adhesive means an adhesive that is cured by irradiation of active energy rays.

The active energy ray-curable adhesives usable in the present invention include (1) a first epoxy compound having a glass transition temperature of homopolymer of 120 ° C. or more (2) a second epoxy compound having a glass transition temperature of homopolymer of 60 ° C. or less and (3) It is preferable to include a photo cationic polymerization initiator.

More specifically, the active energy ray-curable adhesive includes (1) 100 parts by weight of the first epoxy compound having a glass transition temperature of homopolymer of 120 ° C. or more, and (2) a second epoxy having a glass transition temperature of homopolymer of 60 ° C. or less. It is preferred to include 30 to 100 parts by weight of the compound, and 0.5 to 20 parts by weight of the (3) photo cationic polymerization initiator.

When using two or more epoxy compounds having different glass transition temperatures as described above, the homopolymer having a low glass transition temperature plays an advantageous role in adhesion and viscosity, and when the homopolymer having a high glass transition temperature is used together, the glass transition temperature does not decrease. It is advantageous in thermal shock.

As used herein, an epoxy compound refers to a compound having one or more epoxy groups in a molecule, preferably a compound having two or more epoxy groups in a molecule, and is in the form of a monomer, a polymer, or a resin. The concept includes all of the compounds. Preferably the epoxy compound of the present invention may be in the form of a resin.

The first epoxy compound may be used without particular limitation as long as the glass transition temperature of the homopolymer is 120 ° C. or higher. For example, the alicyclic epoxy compound and / or the aromatic epoxy having a glass transition temperature of the homo polymer is 120 ° C. or higher. May be used as the first epoxy compound of the present invention. Specific examples of the epoxy compound having a glass transition temperature of homopolymer of 120 ° C. or higher include 3,4-epoxycyclohexylmethyl-3,4′-epoxycyclohexanecarboxylate, vinylcyclohexenedioxide dicyclopentadiene dioxide, and bisepoxycyclo. A pentyl ether, a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, etc. are mentioned. On the other hand, the first epoxy compound is more preferably the glass transition temperature of the homopolymer is about 120 ℃ to 200 ℃.

Next, the second epoxy compound may be used without particular limitation as long as the glass transition temperature of the homopolymer is an epoxy compound of 60 ° C. or less. For example, an alicyclic epoxy compound, an aliphatic epoxy compound, or the like may be used as the second epoxy compound.

In this case, as the alicyclic epoxy compound, it is preferable to use a bifunctional epoxy compound, i.e., a compound having two epoxy, and it is more preferable to use a compound in which the two epoxy groups are both alicyclic epoxy groups. It is not limited.

As an aliphatic epoxy compound, the epoxy compound which has an aliphatic epoxy group other than an alicyclic epoxy group can be illustrated. For example, polyglycidyl ether of aliphatic polyhydric alcohol; Polyglycidyl ethers of alkylene oxide adducts of aliphatic polyhydric alcohols; Polyglycidyl ethers of polyester polyols of aliphatic polyhydric alcohols and aliphatic polyhydric carboxylic acids; Polyglycidyl ethers of aliphatic polyvalent carboxylic acids; Polyglycidyl ethers of polyester polycarboxylic acids of aliphatic polyhydric alcohols and aliphatic polyhydric carboxylic acids; Dimers, oligomers or polymers obtained by vinyl polymerization of glycidyl acrylate or glycidyl methacrylate; Or oligomers or polymers obtained by vinyl polymerization of glycidyl acrylate or glycidyl methacrylate with other vinyl monomers, preferably polyglycidyl of aliphatic polyhydric alcohols or their alkylene oxide adducts. Ether may be used, but is not limited thereto.

As the aliphatic polyhydric alcohol, for example, an aliphatic polyhydric alcohol having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms or 2 to 4 carbon atoms may be exemplified. Ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-butanediol, neo Pentyl glycol, 3-methyl-2,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 3,5-heptanediol, 1,8-octanediol, 2-methyl-1,8- Aliphatic diols such as octanediol, 1,9-nonanediol and 1,10-decanediol; Alicyclic diols such as cyclohexanedimethanol, cyclohexanediol, hydrogenated bisphenol A and hydrogenated bisphenol F; Trimethylol ethane, trimethylol propane, hexitols, pentitols, glycerin, polyglycerol, pentaerythritol, dipentaerythritol, tetramethylol propane and the like can be exemplified.

In addition, as the alkylene oxide in the above, alkylene oxide of 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms or 1 to 4 carbon atoms can be exemplified, for example, ethylene jade Seeds, propylene oxide or butylene oxide and the like can be used.

Moreover, as said aliphatic polyhydric carboxylic acid, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, subberic acid, azelaic acid, sebacic acid, dodecaneic acid, 2-methyl succinic acid , 2-methyl adipic acid, 3-methyl adipic acid, 3-methylpentaneic acid, 2-methyloctanoic acid, 3,8-dimethyldecane diacid, 3,7-dimethyldecane diacid, 1,20-eicosamethylene Dicarboxylic acid, 1,2-cyclopentanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1 , 4-cyclohexanedicarboxylic acid, 1,4-dicarboxymethylenecyclohexane, 1,2,3-propanetricarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, 1,2 , 3,4-cyclobutanetetracarboxylic acid and the like can be exemplified, but is not limited thereto.

Preferably, the second epoxy compound of the present invention may include one or more glycidyl ether groups, for example, 1,4-cyclohexanedimethanol diglycidyl ether, 1,4-butanediol diggle Cydyl ether, 1,6-hexanediol diglycidyl ether, neopentyl diglycidyl ether, resorcinol diglycidyl ether, diethylene glycol diglycidyl ether, ethylene glycol diglycidyl ether, One selected from the group consisting of trimethylolpropanetriglycidyl ether, n-butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and o-cresyl glycidyl ether The above can be used as the second epoxy compound of the present invention.

On the other hand, the second epoxy compound is more preferably the glass transition temperature of the homopolymer of about 0 ℃ to 60 ℃.

Meanwhile, the present invention is not limited thereto, but in the present invention, it is preferable to use a combination of the first epoxy compound including at least one epoxidized aliphatic ring group and the second epoxy compound including at least one glycidyl ether group as the epoxy compound. Particularly preferred. In the case of using the combination of the first epoxy compound and the second epoxy compound as described above, not only the low viscosity and the adhesive strength were satisfied, but the thermal shock properties of the polarizing plate were improved.

On the other hand, the second epoxy compound is preferably included in an amount of 30 to 100 parts by weight based on 100 parts by weight of the first epoxy compound. If the content of the second epoxy compound exceeds 100 parts by weight, the glass transition temperature of the entire adhesive composition is lowered, the heat resistance is lowered, if less than 30 parts by weight it is because the adhesive force may be lowered.

More preferably, in the active energy ray-curable adhesive, the weight ratio of the first epoxy compound and the second epoxy compound is about 1: 1 to 3: 1, and more preferably, the weight ratio of 1: 1 to 2: 1. Most preferably, the first epoxy compound and the second epoxy compound may be mixed in a weight ratio of 1: 1. When the weight ratio of the first epoxy compound and the second epoxy compound satisfies the above range, most preferable physical properties can be obtained in terms of glass transition temperature and adhesive force.

On the other hand, the cationic photopolymerization initiator is a compound that produces a cation species or Lewis acid by irradiation of active energy rays, for example, onium salts such as aromatic diazonium salts, aromatic iodide aluminum salts and aromatic sulfonium salts, Iron-arene complexes and the like, but are not limited thereto. Meanwhile, the content of the cationic photopolymerization initiator is about 0.5 to 20 parts by weight, preferably about 0.5 to 15 parts by weight, and more preferably about 0.5 to 10 parts by weight based on 100 parts by weight of the first epoxy compound. .

On the other hand, the active energy ray-curable adhesive may further include 100 to 400 parts by weight of an oxetane compound having at least one oxetanyl group in the molecule, if necessary. When using an oxetane compound, the viscosity of an adhesive agent can be lowered and thinning of an adhesive bond layer can be carried out.

The oxetane compound is not particularly limited as long as it has at least one oxetanyl group in the molecule, and various oxetane compounds well known in the art can be used. For example, as the oxetane compound of the present invention, 3-ethyl-3-[(3-ethyloxetan-3-yl) methoxymethyl] oxetane, 1,4-bis [(3-ethyl jade Cetane-3-yl) methoxymethyl] benzene, 1,4-bis [(3-ethyloxetan-3-yl) methoxy] benzene, 1,3-bis [(3-ethyloxetan-3-yl ) Methoxy] benzene, 1,2-bis [(3-ethyloxetan-3-yl) methoxy] benzene, 4,4'-bis [(3-ethyloxetan-3-yl) methoxy] ratio Phenyl, 2,2'-bis [(3-ethyloxetan-3-yl) methoxy] biphenyl, 3,3 ', 5,5'-tetramethyl-4,4'-bis [(3-ethyl Oxetan-3-yl) methoxy] biphenyl, 2,7-bis [(3-ethyloxetan-3-yl) methoxy] naphthalene, bis [4-{(3-ethyloxetan-3-yl ) Methoxy} phenyl] methane, bis [2-{(3-ethyloxetan-3-yl) methoxy} phenyl] methane, 2,2-bis [4-{(3-ethyloxetan-3-yl ) Methoxy} phenyl] propane, etherified modified product of novolak type phenol-formaldehyde resin with 3-chloromethyl-3-ethyloxetane, 3 (4), 8 (9) -bis [(3-ethyl Oxetane 3-yl) methoxymethyl] -tricyclo [5.2.1.0 2,6] decane, 2,3-bis [(3-ethyloxetan-3-yl) methoxymethyl] norbornane, 1,1, 1-tris [(3-ethyloxetan-3-yl) methoxymethyl] propane, 1-butoxy-2,2-bis [(3-ethyloxetan-3-yl) methoxymethyl] butane, 1 , 2-bis [{2- (3-ethyloxetan-3-yl) methoxy} ethylthio] ethane, bis [{4- (3-ethyloxetan-3-yl) methylthio} phenyl] sulfide And 1,6-bis [(3-ethyloxetan-3-yl) methoxy] -2,2,3,3,4,4,5,5-octafluorohexane and the like. On the other hand, the content of the oxetane compound is preferably 100 to 400 parts by weight, more preferably about 150 to 300 parts by weight based on 100 parts by weight of the first epoxy compound.

In the case of having two oxetanyl groups as the oxetane compound, it is effective to increase the glass transition temperature of the adhesive layer, and in the case of having one oxetanyl group, it is advantageous to the adhesive force.

On the other hand, the active energy ray-curable adhesive, together with the components, may further include a vinyl-based compound, if necessary. When the vinyl compound is added, it is possible to maintain low viscosity and to reduce the phenomenon that the glass transition temperature of the adhesive layer is lowered after curing.

As the vinyl compound, for example, hydroxy C _1-6 alkyl vinyl ether and / or vinyl acetate may be used, and the hydroxy C _1-6 alkyl vinyl ether is hydroxyethyl vinyl ether or hydroxy. At least one selected from the group consisting of oxybutyl vinyl ether, 1,4-cyclohexanedimethanol vinyl ether, 4- (hydroxymethyl) cyclohexylmethyl vinyl ether, ethylene glycol vinyl ether, and diethylene glycol monovinyl ether have.

On the other hand, the vinyl compound may be included in a ratio of 0.1 parts by weight to 10 parts by weight, or 0.1 parts by weight to 5 parts by weight with respect to 100 parts by weight of the total adhesive composition.

In addition, the adhesive composition for a polarizing plate of the present invention may further include a silane coupling agent, as necessary, with the above components. When the silane coupling agent is included, the silane coupling agent lowers the surface energy of the adhesive, thereby improving the adhesive wetting property.

At this time, the silane coupling agent more preferably comprises a cationically polymerizable functional group such as an epoxy group, a vinyl group, and a radical group. When the present inventors use the silane coupling agent containing the cationically polymerizable functional group, unlike the case of using the silane coupling agent which does not contain surfactant or cationically polymerizable functional group, wetting property does not reduce the glass transition temperature of an adhesive agent. I found out that it could be improved. It is believed that this is because the cationic polymerizable functional group of the silane coupling agent reacts with the silane group of the adhesive composition to form a crosslinked form, thereby reducing the phenomenon that the glass transition temperature of the adhesive layer is lowered after curing.

Although the silane coupling agent which can be used by this invention is not limited to this, For example, it may be a silane coupling agent represented by following General formula (1).

[Formula 1]

Si (R ₁ ) _n (R ₂ ) _4-n

In Formula 1, R ₁ is a cationically polymerizable functional group bonded to a silicon atom, a functional group including a cyclic ether group or a vinyloxy group, and R ₂ is hydrogen, a hydroxy group, an alkyl group or an alkoxy bonded to a silicon atom. N is an integer of 1-4.

Specific examples of the silane coupling agent satisfying the above [Formula 1] include 2- (3,4-epoxycyclohexyl) ethyl trimethoxy silane, 3-glycidoxypropyl trimethoxy silane, glycidoxypropyl methyldie Oxy silane, glycidoxypropyl triethoxy, vinyltrimethoxysilane or vinyltriethoxysilane may be exemplified, but is not limited thereto.

Moreover, as a silane coupling agent which can be used by this invention, the oligomer type silane compound in which the above-mentioned cationically polymerizable functional group was introduce | transduced in the molecule | numerator of a siloxane oligomer can also be used. In this case, the siloxane oligomer may be a relatively low molecular weight silicone resin in which the terminal of the molecular chain is sealed with an alkoxysilyl group. At this time, the silane compound is preferably included in a ratio of 0.1 parts by weight to 10 parts by weight, or 0.1 parts by weight to 5 parts by weight with respect to 100 parts by weight of the entire adhesive composition. In this range, the adhesive layer may exhibit appropriate surface energy and adhesion.

In addition, the active energy ray hardening-type adhesive agent used by this invention can further contain a radically polymerizable monomer as needed. Examples of the radically polymerizable monomers include various compounds as the radical curable component, and (meth) acrylic functional groups contain one or more, for example, (meth) acrylates and (meth) acrylamides. , Maleimide, (meth) acrylic acid, maleic acid, itaconic acid, (meth) acrylaldehyde, (meth) acryloyl morpholine, N-vinyl-2-pyrrolidone, triallyl isocyanurate and the like can be used. have.

Specific examples of (meth) acrylates having one (meth) acryloyl group in a molecule include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, Butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate, stearyl (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (Meth) acrylate, 1, 4- cyclohexane dimethylol mono (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acryl Latex, benzyl (meth) a (Meth) acrylate of acrylate, phenol alkylene oxide adduct, (meth) acrylate of p-cumylphenol alkylene oxide adduct, (meth) acrylate of o-phenylphenol alkylene oxide adduct, nonylphenol alkylene oxide (Meth) acrylate of adduct (meth) acrylate, 2-methoxyethyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate, (meth) acrylate of alkylene oxide adduct of 2-ethylhexyl alcohol, ethylene glycol mono (Meth) acrylate, propylene glycol mono (meth) acrylate, pentanediol mono (meth) acrylate, hexanediol mono (meth) acrylate, mono (meth) acrylate of diethylene glycol, mono (of triethylene glycol Meta) acrylate, mono (meth) acrylate of tetraethylene glycol, mono (meth) acrylate of polyethylene glycol, mono (meth) acrylate of dipropylene glycol , Mono (meth) acrylate of tripropylene glycol, mono (meth) acrylate of polypropylene glycol, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3-butoxypropyl (Meth) acrylate, tetrahydrofurfuryl (meth) acrylate, caprolactone modified tetrahydrofurfuryl (meth) acrylate, 2-ethyl-2-methyl-1,3-dioxolan-4-yl) methyl ( Meta) acrylate, (2-isobutyl-2-methyl-1,3-dioxolan-4-yl) methyl (meth) acrylate, (1,4-dioxaspiro [4,5] decane-2- Yl) methyl (meth) acrylate, glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, (3-ethyloxetan-3-yl) methyl (meth) acrylate, 2- (meth) acryloyloxymethyl isocyanate, allyl (meth) acrylate, N- (meth) acryloyloxyethyl hexahydrophthalimide, N- (meth) acryloyloxyethylte Trahydrophthalimide, 2- (meth) acryloyloxyethylhexahydrophthalic acid, 2- (meth) acryloyloxyethyl succinic acid, ω-carboxy-polycaprolactone mono (meth) acrylate, 2- (meth) ) Acryloyloxyethyl acid phosphate etc. are mentioned.

Specific examples of the ((meth) acrylamides include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-methylol (meth) acrylamide, N- (3-N, N-dimethylaminopropyl) (meth) acrylamide, methylenebis (meth) acrylamide, ethylenebis (meth) acrylamide, N, N- diallyl (meth) acrylamide, etc. are mentioned. have.

Specific examples of maleimides include N-methylmaleimide, N-hydroxyethylmaleimide, N-hydroxyethylcitraconimide, urethane acrylates of N-hydroxyethylcitraconimide and isophorone diisocyanate, and the like. Can be mentioned.

As a specific example of (meth) acrylates which have two (meth) acryloyl groups in a molecule | numerator, 1, 3- butanediol di (meth) acrylate, 1, 6- hexanediol di (meth) acrylate, 1, 9 -Nonanediol di (meth) acrylate, 1,10-decanedioldi (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 2-methacryloyloxyethyl ethane phosphate, ethylene Glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene Glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, cyclohexanedimethanol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polyethylene glycol (200) di (meth) acrylate, Polyethylene Recall (400) di (meth) acrylate, polyethylene glycol (600) di (meth) acrylate, glycerin di (meth) acrylate, 2-hydroxy-3-acrylooxypropylmethacrylate, dimethylol tricycle Rodecanedi (meth) acrylate etc. are mentioned.

Specific examples of (meth) acrylates having three (meth) acryloyl groups in the molecule include trimethylolpropane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, and trimethylolpropane tri (meth) acrylate. , Ditrimethylolpropane tri (meth) acrylate, trimethylpropane tri (meth) acrylate, tri (2-hydroxy ethyl) isocyanurate triacrylate, tri (2-hydroxy ethyl) isocyanurate, Pentatrithyl triacrylate, ethoxylate trimethylolpropane tri (meth) acrylate, and proxies trimethylolpropane tri (meth) acrylate.

As a specific example of the (meth) acrylate which has four or five (meth) acryloyl groups in a molecule | numerator, pentatrithol tetra (meth) acrylate, ditrimethylolproran tetra (meth) acrylate, dipentatritol penta (Meth) acrylate, an epoxide pentatrithitol tetra (meth) acrylate, a pentaacrylate ester, etc. are mentioned. Specific examples of (meth) acrylates having six (meth) acryloyl groups in the molecule include dipentarititol hexa (meth) acrylate.

The content of the radically polymerizable monomer is about 0 to 40 parts by weight or less based on 100 parts by weight of the total adhesive composition, preferably about 5 to 30 parts by weight, and more preferably about 5 to 25 parts by weight.

On the other hand, when an adhesive composition contains a radically polymerizable monomer as mentioned above, it is preferable to mix | blend a radical photopolymerization initiator in order to promote the radical polymerization property and to improve hardening speed. As the radical photopolymerization initiator, although not limited thereto, for example, an acetophenone-based photoinitiator, a benzoin ether-based photoinitiator, a benzophenone-based photoinitiator, a thioxanthone-based photoinitiator and the like can be used. have. The content of the radical photopolymerization initiator is about 0.5 to 20 parts by weight, preferably about 0.5 to 15 parts by weight, and more preferably about 0.5 to 10 parts by weight based on 100 parts by weight of the total adhesive composition.

In addition, the active energy ray-curable adhesive may further include a photosensitizer, an antioxidant, an oligomer, and an adhesion enhancer, if necessary, preferably further comprising urethane acrylate in an amount greater than 0 to 4 parts by weight. When the urethane acrylate is added as described above, the viscosity tends to increase, but the elevated viscosity of the adhesive may be lowered by adding temperature.

The active energy ray-curable adhesive as described above is excellent in heat resistance at a glass transition temperature of 80 ° C. or higher, preferably 80 ° C. to 120 ° C. after curing. In fact, when the polarizing plate manufactured using the adhesive composition of the present invention evaluated heat resistance and thermal shock resistance at 80 ℃, it was shown that the polarizer crack does not occur.

In addition, the active energy ray-curable adhesive has excellent workability because the viscosity at 25 ° C. is about 15 to 80 cP, preferably about 15 to 50 cP, and shows excellent adhesion at a thin adhesive layer thickness.

In the present invention, the adhesive layer has a thickness of about 10 μm or less, preferably about 0.1 to 5 μm. When the thickness of the adhesive layer exceeds 10 μm, a problem of wrinkles in the appearance of the polarizing plate may occur. When the thickness of the adhesive layer is 0.1 μm or more, it is more preferable in terms of uniformity and adhesive strength of the adhesive layer.

On the other hand, when the transparent polymer film other than the polyethylene terephthalate film is attached to the other surface of the polarizer, the transparent polymer film and the polarizer may also be attached by an adhesive. However, the adhesive used for attaching the polymer film other than polyethylene terephthalate and the polarizer is not particularly limited, and various adhesives used in the art, for example, water-based adhesives such as polyvinyl alcohol-based adhesives, acrylic adhesives, Radical curable adhesives, such as urethane adhesives, photocationic adhesives, such as an epoxy type adhesive, etc. can be used. In view of the convenience of the process, it is more preferable to use an active energy ray adhesive than an aqueous adhesive, but in this case, an active energy ray curable adhesive of the above-mentioned composition is not necessarily used. Accordingly an appropriate adhesive may be used.

(4) primer layer

The polarizing plate of this invention contains the primer layer for improving the adhesive force of an adhesive bond layer and a polyethylene terephthalate film between an adhesive bond layer and a polyethylene terephthalate film.

The primer layer of the present invention is not limited thereto, but for example, at least one binder resin selected from the group consisting of polyester and polyvinyl alcohol resins, acrylic crosslinking agents, epoxy crosslinking agents, and polyvinyl alcohol crosslinking agents. It may be formed by a primer composition comprising at least one crosslinking agent selected from the group consisting of. In this case, the epoxy-based crosslinking agent is not limited thereto, but may include an alicyclic epoxy group or an aromatic epoxy group.

On the other hand, in consideration of the adhesion-improving effect, optical properties, and the like, the primer composition is not limited thereto, but it is preferable to include 0.1 to 50 parts by weight of the crosslinking agent with respect to 100 parts by weight of the binder resin.

Meanwhile, the primer composition may further include components such as waxes, organic fine particles, inorganic fine particles, antifoaming agents, thickeners, lubricants, antioxidants, and the like, in addition to the above components, as necessary, in a range that does not impair the physical properties of the primer composition. .

The primer composition of the present invention can be prepared by a method of mixing or dispersing the above components in an appropriate ratio in water.

On the other hand, the primer layer formed by the primer composition as described above is preferably about 100nm to 1㎛ thickness. When the primer layer is less than 100nm, the adhesion decreases, and when the primer layer is 1 μm or more, drying may not be performed properly when the primer is coated, and blocking may occur due to blocking between the films.

Further, the water contact angle of the surface of the primer layer of the present invention is preferably 40 to 100 degrees, more preferably 50 to 90 degrees, still more preferably 60 to 80 degrees. If the water contact angle is less than 40 degrees, since the hydrophilicity of the primer layer is strong, it may react with the iodine of the polarizer to inhibit the iodine arrangement, resulting in the discoloration of the group color and the polarization degree. If the water contact angle exceeds 100 degrees, the primer layer The hydrophobicity of is so strong that adhesion with the polarizer is difficult.

Meanwhile, when a transparent polymer film other than a polyethylene terephthalate film is attached to the other surface of the polarizer, a primer layer may be provided between the transparent polymer film and the adhesive layer. However, when the adhesion between the polymer film and the adhesive layer is sufficient, the primer layer may be omitted.

The composition of the primer layer formed between the polymer film other than polyethylene terephthalate and the adhesive layer is not particularly limited and may be appropriately selected according to the polymer film and the adhesive layer used. However, considering the convenience and economics of the process, it may be preferable to use the above primer composition.

In the polarizing plate according to the present invention as described above, for example, a primer composition is formed on one surface of a transparent polymer film to form a primer layer, and an active energy ray-curable adhesive composition is applied on one surface of the primer layer or polarizer to form an adhesive layer. Next, the polarizer and the transparent base film may be manufactured by a method of curing the adhesive composition through light irradiation after plywood.

In the polarizing plate of the present invention configured as described above, the polyethylene terephthalate film is attached to one surface of the polarizer, and even when the other type of film is attached to the other surface, the curling properties are excellent, as well as durability, single transmittance, polarization degree, and the like. Properties such as color are also very good. Specifically, the polarizing plate of the present invention has excellent optical properties with a single transmittance of about 40 to 45% and a polarization degree of 99% or more, and when immersed in water at 60 ° C. for 24 hours, discoloration of the polarizing plate in the MD direction is less than 10 mm. It has excellent water resistance.

The polarizing plate of the present invention as described above can be usefully applied to an image display device such as a liquid crystal display device or an organic EL display device. For example, the image display apparatus of the present invention may be a liquid crystal display including a liquid crystal panel and polarizing plates provided on both sides of the liquid crystal panel, wherein at least one of the polarizing plates may be a polarizing plate according to the present invention. have. At this time, the type of liquid crystal panel included in the liquid crystal display device is not particularly limited. For example, a panel of a passive matrix type such as, but not limited to, a twisted nematic (TN) type, a super twisted nematic (STN) type, a ferrolectic (F) type, or a polymer dispersed (PD) type; Active matrix panels, such as two-terminal or three-terminal; All known panels, such as an In Plane Switching (IPS) panel and a Vertical Alignment (VA) panel, can be applied. In addition, other configurations constituting the liquid crystal display device, for example, types of upper and lower substrates (eg, color filter substrates or array substrates) are not particularly limited, and configurations known in the art may be employed without limitation. Can be.

Preparation Example 1 Adhesive A

3,4-epoxycyclohexylmethyl-3,4'-epoxycyclohexanecarboxylate having a glass transition temperature of homopolymer of 190 DEG C (Celloxide 2021P from Diel) and 1 having a glass transition temperature of 25 DEG C. 25 weight% of 2-cyclohexane dimethanol diglycidyl ether, 50 weight of 3-ethyl-3-[(3-ethyloxetan-3-yl) methoxymethyl] oxetane (doagosei Aaron oxetane DOX221) 5 parts by weight of CPI 100P (Sanapro), which is a cationic initiator, was added to 100 parts by weight of the resin composition prepared by adding% to prepare an adhesive composition A for a polarizing plate. The viscosity of the prepared adhesive composition A was 35 cP, and the glass transition temperature was 102 ° C.

Example 1

Primer composition comprising a polyester resin and an epoxy crosslinking agent on one surface of a polyethylene terephthalate film (a resin composition blended with a polyester resin and an epoxy crosslinking agent [manufacturer: TAKAMATSU, trade name: A115GE] 40 parts by weight, 3 parts by weight of silica) And 57 parts by weight of water) to prepare a polyethylene terephthalate film having a primer layer formed.

Corona treated triacetylcellulose film (manufacturer: Fujifilm, brand name: NRT) was prepared.

Then, the adhesive A prepared in Preparation Example 1 was applied to both sides of the polarizer, the polyethylene terephthalate film and the triacetyl cellulose film (NRT film) were laminated, and then passed through a laminator. At this time, the primer layer of the polyethylene terephthalate film was laminated so that the adhesive layer. Then, using a UV irradiation device (metal halide lamp), the polarizing plate made of a structure of PET film / primer layer / adhesive layer / polarizer / adhesive layer / NRT film by irradiating 500mJ / cm ² ultraviolet rays to cure the adhesive layer Was prepared.

Comparative Example 1

A polarizing plate was manufactured in the same manner as in Example 1, except that a corona treated triacetylcellulose film (manufacturer: Fuji Film, trade name: UZ TAC) was used instead of the polyethylene terephthalate film having a primer layer formed thereon. The prepared polarizing plate produced a polarizing plate composed of a structure of UZ TAC film / adhesive layer / polarizer / adhesive layer / NRT film.

Comparative Example 2

A primer composition including a polyester resin and an acrylic crosslinking agent was coated on one surface of the polyethylene terephthalate film to prepare a polyethylene terephthalate film having a primer layer formed thereon.

Corona treated triacetylcellulose film (manufacturer: Fujifilm, brand name: NRT) was prepared.

Then, an aqueous adhesive including acetoacetyl group-modified polyvinyl alcohol-based resin and glyoxalate as a crosslinking agent was applied to both sides of the polarizer, and the polyethylene terephthalate film and the triacetyl cellulose film (NRT film) were laminated, and then a laminator Passed. At this time, the primer layer of the polyethylene terephthalate film was laminated so that the adhesive layer. Then, the adhesive layer was cured by drying in an oven at 80 ° C. for 5 minutes to prepare a polarizing plate having a structure of PET film / primer layer / adhesive layer / polarizer / adhesive layer / NRT film.

Comparative Example 3

A polarizing plate was manufactured in the same manner as in Comparative Example 2, except that a corona-treated triacetylcellulose film (manufacturer: Fuji Film, trade name: UZ TAC) was used instead of the polyethylene terephthalate film having a primer layer formed thereon. The prepared polarizing plate produced a polarizing plate composed of a structure of UZ TAC film / adhesive layer / polarizer / adhesive layer / NRT film.

Comparative Example 4

A polarizing plate was manufactured in the same manner as in Example 1, except that a polyethylene terephthalate film without a primer layer was used. The polarizer produced It was a structure of PET film / adhesive layer / polarizer / adhesive layer / NRT film.

Comparative Example 5

A polarizing plate was manufactured in the same manner as in Example 1, except that a primer composition including a polyester resin and a urethane crosslinking agent was used instead of a primer composition including a polyester resin and an epoxy crosslinking agent.

Comparative Example 6

A polarizing plate was manufactured in the same manner as in Example 1, except that a primer composition including a polyurethane resin was used instead of a primer composition including a polyester resin and an epoxy-based crosslinking agent.

Experimental Example 1-Curl Characteristic Measurement

The curling properties of the polarizing plates produced by Example 1 and Comparative Examples 1 to 6 were visually observed. 1 to 7 are photographs showing the polarizer curl characteristics of Example 1 and Comparative Examples 1 to 6 are shown. 1 to 7, it can be seen that curling is not generated in the polarizing plate of Example 1, whereas curling is generated in the polarizing plates manufactured by Comparative Examples 1 to 6.

Experimental Example 2-Water Resistance Measurement

After the polarizing plate prepared in Example 1 and the polarizing plate prepared in Comparative Example 1 were immersed in water at a temperature of 60 ° C. for 24 hours, the polarizing plate state was visually observed. 8 is a photograph showing a state after immersing the polarizing plates of Example 1 and Comparative Example 1 for 24 hours. 8, in the case of the polarizing plate of Example 1, there was almost no change even after 24 hours of immersion, whereas the polarizing plate of Comparative Example 1 began to discolor in the terminal portion after 4 hours of immersion, and after the 24 hours of immersion, a large polarizing plate It can be seen that discoloration has occurred.

Example 2

A primer composition comprising a polyester resin and an epoxy-based crosslinking agent on a polyethylene terephthalate film coated with a low refractive index layer formed by applying an acrylic resin mixed with 1,1,1-trifluoroethane on one surface (polyester resin and A polyethylene terephthalate film having a primer layer was prepared by coating a resin composition (manufacturer: TAKAMATSU, trade name: A115GE) 40 parts by weight, 3 parts by weight of silica and 57 parts by weight of water) blended with an epoxy-based crosslinking agent.

Next, the poly (N-cyclohexanemaleimide-co-methyl methacrylate-co-α-methyl-styrene) resin composition was supplied to an extruder of 24 φ which was nitrogen-substituted from the raw material hopper to the extruder and melted at 240 ° C. To prepare a raw pellet (pellet). The obtained raw material pellets were vacuum dried, then fed from an raw material hopper to a twin extruder substituted with nitrogen, melted with an extruder at 260 ° C., passed through a T-die of a coat hanger type, and a chrome plated casting roll and An acrylic optical film was manufactured through a drying roll. The optical film thus prepared was held at 135 ° C. for 2 minutes using a biaxial stretching machine, and then stretched at 100% in the MD direction and 100% in the TD direction to prepare an acrylic film.

After the corona treatment of the acrylic film thus prepared, and coated with 10% by weight of the primer composition prepared by diluting CK-PUD-F (lighting urethane dispersion) with pure water thereon, an acrylic film having a urethane-based primer layer was formed. .

Then, the adhesive A prepared in Preparation Example 1 was applied to both sides of the polarizer, the polyethylene terephthalate film and the acrylic film were laminated, and then passed through a laminator. At this time, the primer layer of the polyethylene terephthalate film and the acrylic film was laminated so that the adhesive layer. Then, using UV irradiation device (metal halide lamp), by irradiating UV light of 500mJ / cm ² to cure the adhesive layer to the structure of PET film / primer layer / adhesive layer / polarizer / adhesive layer / primer layer / acrylic film A polarizing plate made of was prepared.

Comparative Example 7

A polarizing plate was manufactured in the same manner as in Example 2 except for using a corona treated corona treated triacetylcellulose film (manufacturer: Fuji Film, trade name: NRT) instead of the polyethylene terephthalate film having a primer layer formed thereon. The produced polarizing plate was a structure of NRT film / adhesive layer / polarizer / adhesive layer / primer layer / acrylic film.

Experimental Example 3-Measurement of Optical Properties

Optical properties and colors (color values according to the CIE color coordinate system) of the polarizing plates prepared in Example 2 and Comparative Example 7 were measured using a JASCO-V-7100 Spectrophotometer. The measurement results are as described in the following [Table 1].

Table 1

division	Ts (%)	Group a	Group b	DOP (polarization degree)	x	y	Orthogonal b
Comparative Example 7	42.69	-1.53	3.47	99.9946	0.196	0.115	-0.92
Example 2	43.05	-1.68	3.84	99.9951	0.217	0.148	-0.57

As described in [Table 1], Example 2 including the PET film having the low refractive index layer was confirmed that compared with Comparative Example 7, showing the same degree of polarization degree and at the same time improve the single transmittance. In addition, in Example 2, since the values of the group colors a, b and the orthogonal color b are relatively larger, the color of the polarizing plate was less bluish than that of Comparative Example 7, and thus the color characteristics were also excellent.

Experimental Example 4-Heat Resistance Measurement

The polarizing plates prepared in Example 2 and Comparative Example 7 were placed in an oven at 80 ° C. for 100 hours, then left at room temperature for 12 hours, and then the degree of change in optical properties and color was measured. The measurement results are shown in [Table 2].

TABLE 2

division	△ Ts (%)	△ Group a	△ Group b	△ DOP	Δx	△ y	△ orthogonal b
Comparative Example 7	0.26	-0.16	1.25	-0.0016	0.049	0.095	0.73
Example 2	0.13	-0.19	1.25	-0.0019	0.047	0.092	0.48

As shown in Table 2, in the case of the polarizing plate of Example 2, it can be seen that the change rate of the single transmittance change and the orthogonal color b-value under the high temperature condition is much smaller than that of the comparative example 7, and thus the heat resistance is excellent.

Claims (24)

1. A polarizing plate provided with at least one surface of the polarizer adhesive layer, primer layer and polyethylene terephthalate film in this order,

   The adhesive layer is formed by an active energy ray-curable adhesive comprising a first epoxy compound having a glass transition temperature of at least 120 ° C., a second epoxy compound having a glass transition temperature of at least 60 ° C., and a cationic photopolymerization initiator. ,

   The primer layer comprises a primer composition comprising at least one binder resin selected from the group consisting of polyester and polyvinyl alcohol resins and at least one crosslinking agent selected from the group consisting of acrylic crosslinking agents, epoxy crosslinking agents and polyvinyl alcohol crosslinking agents. Formed by Polarizing plate.
2. The method of claim 1,

   The said polyethylene terephthalate film has a water vapor transmission rate of 100 g / m <^2> * day or less, and a moisture content is 1 weight% or less.
3. The method of claim 1,

   The polyethylene terephthalate film has a low refractive index layer having a refractive index of 1.4 to 1.5 is formed on at least one surface.
4. The method of claim 1,

   The polyethylene terephthalate film has a total refractive index of 1.48 to 1.55 polarizing plate.
5. The method of claim 1,

   The active energy ray-curable adhesive includes 100 parts by weight of the first epoxy compound having a glass transition temperature of at least 120 ° C., and 30 to 100 parts by weight of a second epoxy compound having a glass transition temperature of at least 60 ° C., and a cationic photopolymerization initiator. Polarizing plate comprising 0.5 to 20 parts by weight.
6. The method of claim 1,

   The first epoxy compound is at least one polarizing plate selected from the group consisting of an alicyclic epoxy compound and an aromatic epoxy.
7. The method of claim 6,

   The first epoxy compound is 3,4-epoxycyclohexylmethyl-3,4'-epoxycyclohexanecarboxylate, vinylcyclohexene dioxide dicyclopentadiene dioxide, bisepoxycyclopentyl ether, bisphenol A-based epoxy compound and bisphenol F At least one polarizing plate selected from the group consisting of epoxy compounds.
8. The method of claim 1,

   The second epoxy compound is at least one member selected from the group consisting of an alicyclic epoxy compound and an aliphatic epoxy compound.
9. The method of claim 8,

   The second epoxy compound is a polarizing plate containing one or more glycidyl ether groups.
10. The method of claim 9,

    The second epoxy compound is 1,4-cyclohexanedimethanol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl diglycidyl ether, rezo Synol diglycidyl ether, diethylene glycol diglycidyl ether, ethylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, n-butyl glycidyl ether, 2-ethylhexyl glycidyl ether At least one member selected from the group consisting of phenyl glycidyl ether, and o-cresyl glycidyl ether.
11. The method of claim 1,

    The active energy ray curable adhesive includes the first epoxy compound and the second epoxy compound in a weight ratio of 1: 1 to 3: 1.
12. The method of claim 1,

    The active energy ray-curable adhesive further comprises 100 to 400 parts by weight of an oxetane compound having at least one oxetanyl group in a molecule.
13. The method of claim 1,

    The active energy ray-curable adhesive further includes a vinyl compound, and the content of the vinyl compound is 0.1 to 10 parts by weight based on 100 parts by weight of the total adhesive.
14. The method of claim 13,

    The vinyl compound is at least one selected from the group consisting of hydroxy C _1-6 alkyl vinyl ether and vinyl acetate.
15. The method of claim 1,

    The active energy ray-curable adhesive further comprises a silane coupling agent, wherein the content of the silane coupling agent is 0.1 to 5 parts by weight based on 100 parts by weight of the total adhesive.
16. The method of claim 15,

    Wherein said silane coupling agent comprises at least one cationic polymerizable functional group selected from the group consisting of an epoxy group, a vinyl group, a radical group and a combination thereof.
17. The method of claim 1,

    The cationic polymerizable adhesive further includes a radical polymerizable monomer, and the content of the radical polymerizable monomer is greater than 0 and less than 40 parts by weight based on 100 parts by weight of the total adhesive.
18. The method of claim 17,

    The active energy ray-curable adhesive further includes an optical radical polymerization initiator, and the content of the radical photopolymerization initiator is 0.5 to 20 parts by weight based on 100 parts by weight of the total adhesive.
19. The method of claim 1,

    The active energy ray-curable adhesive is a polarizing plate having a glass transition temperature of 80 ℃ to 120 ℃.
20. The method of claim 1,

    The active energy ray-curable adhesive is a polarizing plate having a viscosity of 15 to 50 cP at 25 ℃.
21. The method of claim 1,

    A polyethylene terephthalate film is disposed on one surface of the polarizer,

    The polarizing plate is disposed on the other surface of the polarizer is a transparent polymer film selected from the group consisting of a triacetyl cellulose film, a cycloolefin polymer film, a polyester film, a polycarbonate film and an acrylic film.
22. The method of claim 21,

    The transparent polymer film attached to the other surface of the polarizer is a uniaxial stretched film or biaxially stretched film having a phase difference.
23. An image display device comprising the polarizing plate of any one of claims 1 to 22.
24. The method of claim 23,

    The image display device is a liquid crystal display device or an organic EL display device.

Images