JP5811431B2 - Polarizing plate and liquid crystal display device - Google Patents

Description

  The present invention relates to a polarizing plate and a liquid crystal display device using the polarizing plate.

  In recent years, low-power consumption, low-voltage operation, lightweight and thin liquid crystal display devices are rapidly spreading as information display devices such as mobile phones, portable information terminals, computer monitors, and televisions. . Further, along with the development of the liquid crystal technology, liquid crystal display devices of various modes have been proposed, and the conventional problems of the liquid crystal display devices such as response speed, contrast, and viewing angle are being solved.

  On the other hand, in response to strong market demands for further reduction in thickness and weight of liquid crystal display devices, liquid crystal panels, diffusion plates, backlight units, and drive ICs constituting liquid crystal display devices have been made thinner and smaller. Yes. Under such circumstances, it is required to reduce the thickness of the polarizing plate, which is a member constituting the liquid crystal panel, in units of 10 μm.

  At the same time, with the widespread use of liquid crystal display devices, the demand for cost reduction from the market is increasing day by day, and further cost reduction and productivity improvement are essential for polarizing plates.

  Various proposals have been made so far to satisfy these requirements. For example, a polarizing plate usually has a structure in which a transparent protective film is provided on one or both sides of a polarizing film, and triacetyl cellulose is generally used as the transparent protective film. As disclosed in the publication (Patent Document 1), attempts have been made to reduce the number of components and simplify the production process by providing an optical compensation function by providing a phase difference to the protective film. With such a configuration, the composite polarizing plate, which is a laminate of the polarizing plate and the retardation plate, can be reduced in thickness and weight, and further, the number of constituent members of the liquid crystal display device can be reduced, so that the production process It is possible to simplify the process, improve the yield, and reduce the cost.

  Furthermore, an attempt to replace the protective film with a resin other than triacetyl cellulose is also actively advanced. For example, Japanese Patent Application Laid-Open No. 7-77608 (Patent Document 2) discloses a means for using a cyclic olefin resin instead of triacetyl cellulose. However, since cyclic olefin-based resins are generally expensive, they are currently used for higher-value-added retardation films, and cannot be balanced in terms of cost reduction when used as mere protective films. Has the problem.

  As a technique that can satisfy the above requirements, a technique using a polyethylene terephthalate film as a protective film has been proposed. Since polyethylene terephthalate is excellent in mechanical strength, it is suitable for thinning, and the polarizing plate can be made thin. Furthermore, it is generally superior in terms of cost as compared with triacetyl cellulose and cyclic olefin resins. In addition, compared to triacetyl cellulose, it has characteristics such as low moisture permeability and low water absorption, so it can be expected to have excellent resistance to moisture and heat shock and high durability against environmental changes. .

  However, on the other hand, when a polarizing plate using a polyethylene terephthalate film as a protective film is mounted on a liquid crystal display device, compared to a general polarizing plate using a triacetyl cellulose film as a protective film, an oblique derived from its high retardation value. Color unevenness from the direction (also referred to as interference unevenness or rainbow unevenness) is conspicuous and has a problem of poor visibility. With respect to this problem, for example, in Japanese Patent Application Laid-Open No. 2009-109993 (Patent Document 3), a liquid crystal display combining a polarizing plate using a polyethylene terephthalate film as a protective film and a polarizing plate provided with an antiglare layer with a controlled haze value. A method of reducing color unevenness by configuring an apparatus is disclosed. However, even if this method is used, the reduction in color unevenness is insufficient, and establishment of a more effective method has been desired.

JP-A-8-43812 JP-A-7-77608 JP 2009-10993 A

  Therefore, an object of the present invention is a polarizing plate using a polyethylene terephthalate film as a protective film, which has little color unevenness when mounted on a liquid crystal display device, is excellent in visibility, is thin, and has a low cost performance and production. It is providing the polarizing plate which is excellent also in property. Another object of the present invention is to provide a liquid crystal display device having excellent visibility using the polarizing plate.

The present inventors have conducted intensive research to solve the above-described color unevenness problem. As a result, refracted at the polarizing plate to protect the polyethylene terephthalate film film, the slow axis direction of the refractive index n _x in the plane, the refractive index in a direction perpendicular to the slow axis in the plane n _y, in the thickness direction the rate is taken as n _z, by using as a protective film _{(n x -n z) / (} n x -n y) Nz coefficient expressed by is less than 2.0 oriented polyethylene terephthalate film, a liquid crystal display It has been found that the color unevenness of the apparatus can be effectively reduced, and both high visibility, thinning and cost reduction can be realized.

That is, according to the present invention, a stretched polyethylene terephthalate film comprising: a polarizing film made of a polyvinyl alcohol-based resin; and a stretched polyethylene terephthalate film laminated on one side of the polarizing film via a first adhesive layer. the slow axis direction of the refractive index n _x in the plane, the refractive index in a direction perpendicular to the slow axis in the plane n _y, the refractive index in the thickness direction is taken as n _z, (n _x - a polarizing plate is provided, wherein n _z) / (Nz coefficient expressed by n _x -n _y) is less than 2.0.

  In the polarizing plate of the present invention, the stretched polyethylene terephthalate film preferably has an in-plane retardation value of 200 to 1200 nm or 2000 to 7000 nm.

  The first adhesive layer is preferably composed of a cured product layer of an active energy ray-curable composition containing an alicyclic epoxy compound.

  The polarizing plate of the present invention may include a protective film or an optical compensation film laminated via a second adhesive layer on the surface opposite to the surface on which the stretched polyethylene terephthalate film is laminated in the polarizing film. it can.

  The protective film or the optical compensation film is composed of a transparent resin film selected from a cyclic olefin resin film, a cellulose resin film, a polycarbonate resin film, a chain olefin resin film, a polyester resin film, and an acrylic resin film. It is preferred that

  The second adhesive layer is preferably composed of a cured product layer having the same composition as the active energy curable composition forming the first adhesive layer.

  When laminating a protective film or an optical compensation film as described above, the polarizing plate of the present invention is a pressure-sensitive adhesive laminated on the surface opposite to the surface on which the polarizing film is laminated in the protective film or the optical compensation film. A layer can be provided.

  The polarizing plate of the present invention is selected from an antiglare layer, a hard coat layer, an antireflection layer, and an antistatic layer laminated on the surface opposite to the surface on which the polarizing film is laminated in the stretched polyethylene terephthalate film. It is preferable to provide at least one layer.

  Moreover, according to this invention, a polarizing plate provided with the said adhesive layer is provided with a liquid crystal display device provided with the liquid crystal panel bonded by the liquid crystal cell through the adhesive layer.

  According to the present invention, by using a stretched polyethylene terephthalate film having an Nz coefficient of less than 2.0 as a protective film, the liquid crystal display device exhibits excellent visibility with little color unevenness at the time of display, and realizes thinning. In addition, a polarizing plate having excellent cost performance and productivity can be provided. Moreover, according to this invention, the liquid crystal display device which is excellent in the visibility using the said polarizing plate can be provided.

<Polarizing plate>
The polarizing plate of this invention is equipped with the polarizing film which consists of polyvinyl alcohol-type resin, and the extending | stretching polyethylene terephthalate film laminated | stacked through the 1st adhesive bond layer on the single side | surface of this polarizing film. Further, the polarizing plate of the present invention includes a protective film or an optical compensation film laminated via a second adhesive layer on the surface of the polarizing film opposite to the surface on which the stretched polyethylene terephthalate film is laminated. It may be. Hereinafter, the polarizing plate of the present invention will be specifically described.

(Polarizing film)
The polarizing film used in the present invention is usually a step of uniaxially stretching a polyvinyl alcohol resin film by a known method, a step of adsorbing a dichroic dye by dyeing the polyvinyl alcohol resin film with a dichroic dye, The polyvinyl alcohol resin film on which the dichroic dye is adsorbed is manufactured through a step of treating with a boric acid aqueous solution and a step of washing with water after the treatment with the boric acid aqueous solution.

  As the polyvinyl alcohol resin, a saponified polyvinyl acetate resin can be used. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers with other monomers copolymerizable with vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

  The saponification degree of the polyvinyl alcohol resin is usually about 85 to 100 mol%, preferably 98 mol% or more. This polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal and polyvinyl acetal modified with aldehydes can also be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, and preferably about 1,500 to 5,000.

  What formed such a polyvinyl alcohol-type resin into a film is used as a raw film of a polarizing film. The method for forming a polyvinyl alcohol-based resin is not particularly limited, and can be formed by a known method. The film thickness of the polyvinyl alcohol-based raw film is not particularly limited, but is, for example, about 10 μm to 150 μm.

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

  In uniaxial stretching, it may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using a hot roll. The uniaxial stretching may be dry stretching in which stretching is performed in the atmosphere, or may be wet stretching in which stretching is performed in a state where a solvent is used and the polyvinyl alcohol-based resin film is swollen. The draw ratio is usually about 3 to 8 times.

  As a method of dyeing the polyvinyl alcohol resin film with the dichroic dye, for example, a method of immersing the polyvinyl alcohol resin film in an aqueous solution containing the dichroic dye is employed. Specifically, iodine or a dichroic dye is used as the dichroic dye. In addition, it is preferable that the polyvinyl alcohol-type resin film performs the immersion process to water before a dyeing process.

  When iodine is used as the dichroic dye, a method of dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide is usually employed. The content of iodine in this aqueous solution is usually about 0.01 to 1 part by weight per 100 parts by weight of water. The content of potassium iodide is usually about 0.5 to 20 parts by weight per 100 parts by weight of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40 ° C. Moreover, the immersion time (dyeing time) in this aqueous solution is usually about 20 to 1,800 seconds.

On the other hand, when a dichroic dye is used as the dichroic dye, a method of immersing and dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye is usually employed. The content of the dichroic dye in this aqueous solution is usually about 1 × 10 ⁻⁴ to 10 parts by weight and preferably about 1 × 10 ⁻³ to 1 part by weight per 100 parts by weight of water. This aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing assistant. The temperature of the aqueous dichroic dye solution used for dyeing is usually about 20 to 80 ° C. Moreover, the immersion time (dyeing time) in this aqueous solution is usually about 10 to 1,800 seconds.

  The boric acid treatment after dyeing with a dichroic dye can usually be performed by immersing the dyed polyvinyl alcohol resin film in a boric acid-containing aqueous solution.

  The amount of boric acid in the boric acid-containing aqueous solution is usually about 2 to 15 parts by weight and preferably 5 to 12 parts by weight per 100 parts by weight of water. When iodine is used as the dichroic dye, the boric acid-containing aqueous solution preferably contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is usually about 0.1 to 15 parts by weight and preferably about 5 to 12 parts by weight per 100 parts by weight of water. The immersion time in the boric acid-containing aqueous solution is usually about 60 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually 50 ° C or higher, preferably 50 to 85 ° C, and more preferably 60 to 80 ° C.

  The polyvinyl alcohol resin film after the boric acid treatment is usually washed with water. The water washing treatment can be performed, for example, by immersing a boric acid-treated polyvinyl alcohol resin film in water. The temperature of water in the water washing treatment is usually about 5 to 40 ° C. Further, the immersion time is usually about 1 to 120 seconds.

  After washing with water, a drying process is performed to obtain a polarizing film. The drying treatment can be performed using a hot air dryer or a far infrared heater. The temperature of the drying treatment is usually about 30 to 100 ° C, and preferably 50 to 80 ° C. The time for the drying treatment is usually about 60 to 600 seconds, and preferably 120 to 600 seconds.

  By the drying treatment, the moisture content of the polarizing film is reduced to a practical level. The water content is usually 5 to 20% by weight, preferably 8 to 15% by weight. When the moisture content is less than 5% by weight, the flexibility of the polarizing film is lost, and the polarizing film may be damaged or broken after drying. Moreover, when a moisture content exceeds 20 weight%, the thermal stability of a polarizing film may be inferior.

  The thickness of the polarizing film thus obtained can usually be about 5 to 40 μm.

(Stretched polyethylene terephthalate film)
The stretched polyethylene terephthalate film used in the present invention is formed by melt-extrusion of one or more polyethylene terephthalate resins, one or more uniaxially stretched films formed by transverse stretching, or longitudinally stretched after film formation, One or more biaxially stretched films formed by transverse stretching. Polyethylene terephthalate can arbitrarily control the anisotropy of the refractive index and the retardation value, Nz value, and optical axis defined by stretching, and in the present invention, it efficiently provides the necessary optical performance. Since it can do, a uniaxially stretched product is preferably used.

  The polyethylene terephthalate resin means a resin in which 80 mol% or more of repeating units are composed of ethylene terephthalate, and may contain other dicarboxylic acid components and diol components. Examples of other dicarboxylic acid components include, but are not limited to, isophthalic acid, 4,4′-dicarboxydiphenyl, 4,4′-dicarboxybenzophenone, bis (4-carboxyphenyl) ethane, adipine Examples include acid, sebacic acid, and 1,4-dicarboxycyclohexane.

  Other diol components are not particularly limited, but propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol Etc.

  These other dicarboxylic acid components and other diol components can be used in combination of two or more if necessary. Further, hydroxycarboxylic acids such as p-hydroxybenzoic acid and p-β-hydroxyethoxybenzoic acid can be used in combination. Further, as other copolymerization component, a dicarboxylic acid component containing a small amount of an amide bond, a urethane bond, an ether bond, a carbonate bond, or the like, or a diol component may be used.

  Polyethylene terephthalate resin can be produced by direct polycondensation of terephthalic acid and ethylene glycol (and other dicarboxylic acids or other diols as required), dialkyl esters of terephthalic acid and ethylene glycol (and if necessary) A transesterification reaction with a dialkyl ester of another dicarboxylic acid or other diol), and a polycondensation, and an ethylene glycol ester of terephthalic acid (and other dicarboxylic acids as required) A method of polycondensation of other diol esters) is employed.

  For each polymerization reaction, a polymerization catalyst composed of an antimony, titanium, germanium, or aluminum compound, or a polymerization catalyst composed of the above composite compound can be used.

  The polymerization reaction conditions may be appropriately selected according to the monomer, catalyst, reaction apparatus, and desired resin physical properties to be used, and are not particularly limited. For example, the reaction temperature is usually about 150 ° C. to The temperature is about 300 ° C, preferably about 200 ° C to about 300 ° C, more preferably about 260 ° C to about 300 ° C. The pressure is usually from atmospheric pressure to about 2.7 Pa, and it is preferable that the pressure is on the reduced pressure side in the latter half of the reaction.

  The polymerization reaction proceeds by devolatilizing a diol, alkyl compound, water or other elimination reaction product by stirring under such high temperature and high pressure reduction conditions.

  In addition, the polymerization apparatus may be completed with a single reaction vessel, or may be a combination of a plurality of reaction vessels. In the latter case, the reactant is usually polymerized while being transferred between the reaction vessels according to the degree of polymerization. Further, a method in which a horizontal reaction apparatus is provided in the latter half of the polymerization and devolatilized while heating and kneading can be employed.

  After the polymerization is completed, the resin is extracted from a reaction vessel or a horizontal reactor in a molten state, and then cooled and crushed by a cooling drum, a cooling belt, or the like, or introduced into an extruder to form a string. After being extruded, it is obtained in the form of a cut pellet.

  Furthermore, solid phase polymerization can be performed as necessary to improve the molecular weight or reduce the low molecular weight components. Examples of the low molecular weight component that can be contained in the polyethylene terephthalate resin include a cyclic trimer component, and the content of such a cyclic trimer component in the resin is preferably 5000 ppm or less, and 3000 ppm or less. Is more preferable. If the cyclic trimer component exceeds 5000 ppm, the optical properties of the film may be adversely affected.

  The molecular weight of the polyethylene terephthalate resin is usually 0.45 to 1.0 dL when the resin is dissolved in a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) and expressed in terms of intrinsic viscosity measured at 30 ° C. / G, preferably 0.50 to 1.0 dL / g, more preferably 0.52 to 0.80 dL / g. When the intrinsic viscosity is less than 0.45 dL / g, the productivity at the time of film production may be lowered, or the mechanical strength of the film may be lowered. Moreover, the thing whose intrinsic viscosity exceeds 1.0 dL / g may be inferior to the melt-extrusion stability of the polymer in film manufacture.

  Moreover, the polyethylene terephthalate resin can contain an additive as necessary. Examples of the additive include a lubricant, an antiblocking agent, a heat stabilizer, an antioxidant, an antistatic agent, a light resistance agent, and an impact resistance improving agent. The addition amount is preferably kept in a range that does not adversely affect the optical properties.

  Polyethylene terephthalate-based resins are usually used in the form of pellets granulated by an extruder for blending such additives and for film formation described later. The size and shape of the pellet are not particularly limited, but are usually cylindrical, spherical, or flat spherical with a height and diameter of 5 mm or less.

  The polyethylene terephthalate-based resin thus obtained can be made into a stretched polyethylene terephthalate film having high mechanical strength, which is transparent and homogeneous, by forming into a film and stretching. The manufacturing method is not particularly limited, but for example, the method described below is adopted.

  First, dried pellets made of polyethylene terephthalate resin are supplied to a melt extrusion apparatus and heated to a melting point or higher to melt. Next, the melted resin is extruded from a die and rapidly cooled and solidified on the rotary cooling drum so that the temperature is equal to or lower than the glass transition temperature to obtain a substantially amorphous unstretched film. The melting temperature is determined according to the melting point of the polyethylene terephthalate resin to be used and the extruder, and is not particularly limited, but is usually 250 to 350 ° C.

  In order to improve the flatness of the film, it is preferable to improve the adhesion between the film and the rotary cooling drum, and an electrostatic application adhesion method or a liquid application adhesion method is preferably employed. In the electrostatic application adhesion method, a linear electrode is usually stretched in the direction perpendicular to the film flow on the upper surface side of the film, and a static voltage is applied to the film by applying a DC voltage of about 5 to 10 kV to the electrode. This is a method for improving the adhesion between the rotary cooling drum and the film. In addition, the liquid application adhesion method improves the adhesion between the rotating cooling drum and the film by uniformly applying the liquid to the entire surface of the rotating cooling drum or a part of it (for example, only the portion that contacts both ends of the film). It is a method to make it. You may use both together as needed.

  The polyethylene terephthalate resin to be used may be mixed with two or more kinds of resins having different resin structures and compositions as necessary. For example, it is possible to use a mixture of pellets containing a particulate filler, an ultraviolet absorber, or an antistatic agent as an antiblocking agent, and non-compounded pellets.

  Moreover, you may make the lamination | stacking number of the film to extrude into 2 or more layers as needed. For example, a pellet containing a granular filler as an antiblocking agent and a non-compounded pellet are prepared and supplied to the same die from different extruders, consisting of two types and three layers of “filler blend / no blend / filler blend”. For example, extruding a film.

  When obtaining a uniaxially stretched film, the unstretched film is usually stretched in the width direction of the film (perpendicular to the longitudinal direction) by a tenter at a temperature equal to or higher than the glass transition temperature. This stretching temperature is usually 70 to 150 ° C, preferably 80 to 130 ° C, and more preferably 90 to 120 ° C. Moreover, a draw ratio is 2.5 to 6 times normally, and it is preferable that it is 3 to 5.5 times. If the draw ratio in the transverse drawing is less than 2.5 times, the transparency of the film may become unfavorable. Moreover, the draw ratio exceeding 6 times is not realistic in manufacturing technology.

  Thereafter, heat treatment and relaxation treatment as necessary can be performed. The heat treatment temperature is usually 150 to 250 ° C, preferably 180 to 245 ° C, and more preferably 200 to 230 ° C. The heat treatment time is usually 1 to 600 seconds, preferably 1 to 300 seconds, and more preferably 1 to 60 seconds.

  The temperature of the relaxation treatment is usually 100 to 230 ° C, preferably 110 to 210 ° C, more preferably 120 to 180 ° C. Moreover, the relaxation amount is usually 0.1 to 20%, preferably 1 to 10%, more preferably 2 to 5%. The temperature and amount of relaxation treatment are preferably set such that the amount of relaxation and the temperature during relaxation treatment are such that the heat shrinkage rate at 150 ° C. of the polyethylene terephthalate film after relaxation treatment is 2% or less.

  On the other hand, when obtaining a biaxially stretched film, the unstretched film is usually first stretched in the extrusion direction at a temperature equal to or higher than the glass transition temperature. The stretching temperature is usually 70 to 150 ° C, preferably 80 to 130 ° C, and more preferably 90 to 120 ° C. Moreover, the draw ratio is 1.1 to 6 times normally, and 2 to 5.5 times is preferable. This is because when the draw ratio is less than 1.1 times, the mechanical strength of the stretched polyethylene terephthalate film tends to be insufficient. Moreover, when it exceeds 6 times, the intensity | strength of a horizontal direction may be insufficient for practical use. This stretching can be completed once or divided into a plurality of times as necessary. Usually, even when stretching is performed a plurality of times, the total stretching ratio is preferably within the above range.

  The longitudinally stretched film thus obtained can then be heat treated. Then, if necessary, relaxation treatment can be performed. This heat treatment temperature is usually 150 to 250 ° C, preferably 180 to 245 ° C, more preferably 200 to 230 ° C. The heat treatment time is usually 1 to 600 seconds, preferably 1 to 300 seconds, and more preferably 1 to 60 seconds.

  The temperature of the relaxation treatment is usually 90 to 200 ° C, preferably 120 to 180 ° C. Further, the relaxation amount is usually 0.1 to 20%, preferably 2 to 5%. More preferably, the temperature and amount of relaxation treatment are set such that the heat shrinkage rate at 150 ° C. of the polyethylene terephthalate film after the relaxation treatment is 2% or less.

  When obtaining a biaxially stretched film, it is usually stretched in the transverse direction by a tenter after the longitudinal stretching treatment or after heat treatment or relaxation treatment as necessary. This stretching temperature is usually 70 to 150 ° C, preferably 80 to 130 ° C, and more preferably 90 to 120 ° C. Moreover, a draw ratio is 1.1-6 times normally, and it is preferable that it is 2-5.5 times. When the draw ratio in the transverse drawing is less than 1.1 times, film strength improvement due to orientation may be insufficient. Moreover, the draw ratio exceeding 6 times is not realistic in manufacturing technology.

  Thereafter, heat treatment and relaxation treatment as necessary can be performed. The heat treatment temperature is usually 150 to 250 ° C, preferably 180 to 245 ° C, and more preferably 200 to 230 ° C. The heat treatment time is usually 1 to 600 seconds, preferably 1 to 300 seconds, and more preferably 1 to 60 seconds.

  The temperature of the relaxation treatment is usually 100 to 230 ° C, preferably 110 to 210 ° C, more preferably 120 to 180 ° C. Moreover, the relaxation amount is usually 0.1 to 20%, preferably 1 to 10%, more preferably 2 to 5%. The temperature and amount of relaxation treatment are preferably set such that the amount of relaxation and the temperature during relaxation treatment are such that the heat shrinkage rate at 150 ° C. of the polyethylene terephthalate film after relaxation treatment is 2% or less.

  In both the uniaxial stretching and biaxial stretching treatments, if the stretching treatment temperature exceeds 250 ° C., the optical performance may deteriorate due to thermal degradation of the resin or excessive crystallization. On the other hand, when the stretching treatment temperature is less than 70 ° C., excessive stress may be applied to stretching, or the film may solidify and stretching itself may be impossible.

  In the uniaxial stretching and biaxial stretching treatments, after transverse stretching, heat treatment is performed again or stretching treatment is performed in order to relieve strain in the stretching direction of the orientation main axis represented by bowing. be able to.

  In addition, a extending | stretching direction here means the direction with a large draw ratio in longitudinal stretch or horizontal stretch. In the biaxial stretching of a polyethylene terephthalate film, the transverse stretching ratio is usually slightly larger than the longitudinal stretching ratio. In this case, the stretching direction refers to a direction perpendicular to the longitudinal direction of the film. Moreover, in uniaxial stretching, since it is normally stretched in the transverse direction as described above, in this case, the stretching direction is the direction perpendicular to the longitudinal direction.

  In addition, the orientation main axis herein refers to a molecular orientation direction at an arbitrary point on the stretched polyethylene terephthalate film, and here refers to a slow axis. The distortion of the orientation main axis (slow axis) with respect to the stretching direction refers to an angular difference between the slow axis and the stretching direction.

  The slow axis can be measured using, for example, a retardation film / optical material inspection apparatus RETS (manufactured by Otsuka Electronics Co., Ltd.) or a molecular orientation meter MOA (manufactured by Oji Scientific Instruments Co., Ltd.).

In oriented polyethylene terephthalate film, the draw ratio in the longitudinal stretching or lateral stretching is a slow axis direction of the refractive index n _x, the refractive index in the direction orthogonal to the slow axis in the plane of the film plane n _y is the most important factor in controlling the n _z is a refractive index in the thickness direction, in the preparation of generally oriented polyethylene terephthalate film, uniaxial _{stretching, (n x -n z) /} (n x -n Biaxial stretching with a relatively small Nz coefficient represented by _y ) is suitable for producing a relatively large film.

  In the polarizing plate of the present invention, the stretched polyethylene terephthalate film having an Nz coefficient of less than 2.0 is used. For this reason, it is preferable to produce a stretched polyethylene terephthalate film by uniaxial stretching. By employing a stretched polyethylene terephthalate film having such optical performance, it is possible to effectively reduce color unevenness in a liquid crystal display device equipped with such a polarizing plate. The smaller the Nz coefficient is, the smaller the color unevenness is reduced. The Nz coefficient is preferably 1.5 or less, more preferably 1.0 or less. When the Nz coefficient is 2.0 or more, strong color unevenness occurs in a liquid crystal display device equipped with such a polarizing plate, resulting in poor visibility. When the Nz coefficient is 2.0 or more and less than 4, a color unevenness reduction effect cannot be obtained. Even when the Nz coefficient is 4 or more, a color unevenness reduction effect can be obtained. In this case, the higher the value of the Nz coefficient, the more advantageous for color unevenness reduction.

Moreover, oriented polyethylene terephthalate film in the polarizing plate of the present invention, the thickness is taken as _{d, (n x -n y)} × plane phase difference value R ₀ as defined in d is 200~1200nm or 2,000 A film having a thickness of 7000 nm can be suitably used. When R ₀ is outside this range, that is, when R ₀ exceeds 1200 and is less than 2000 nm, relatively noticeable color unevenness tends to occur. Therefore, from the viewpoint of reducing color unevenness more effectively, the in-plane retardation value R ₀ is preferably 1200 nm or less or 2000 nm or more. Further, when R ₀ is as small as less than 200 nm, it is difficult to stably control the Nz coefficient to less than 2.0, which causes problems in terms of productivity and cost. On the other hand, when R ₀ exceeds 7000 nm, the Nz coefficient tends to be reduced, but the film tends to be inferior in mechanical strength.

  In the polarizing plate of the present invention, the axial deviation angle of the slow axis of the stretched polyethylene terephthalate film with respect to the transmission axis of the polarizing film can be arbitrarily selected according to the purpose, production restrictions and the like. For example, when the polarizing plate of the present invention is applied as a backlight light source side (incident side) polarizing plate of a liquid crystal display device having a highly polarized backlight light source, the front direction derived from the in-plane retardation of stretched polyethylene terephthalate In order to prevent the interference color from appearing, it is preferable that the axial deviation angle between the polarizing film and the stretched polyethylene terephthalate film is small. Preferably, the deviation angle of the slow axis of the stretched polyethylene terephthalate film with respect to the transmission axis of the polarizing film is preferably in the range of 0 ° to 15 °. Even in such a case, setting the Nz coefficient to less than 2.0 is effective in reducing color unevenness.

  As a backlight light source with strong polarization, for example, a backlight unit including a reflective polarization separation film in a backlight unit can be used. The reflective polarization separation film is a film having a function of improving the luminance in the visible range by selectively reflecting the light of the backlight and reusing it. As a commercially available product corresponding to the reflective polarization separation film, there is “DBEF” (trade name) sold by 3M Company in the US [Sumitomo 3M Co., Ltd. in Japan].

  On the other hand, in cases other than the above, those having a large deviation angle of the slow axis of the stretched polyethylene terephthalate film with respect to the transmission axis of the polarizing film can be preferably used. Among them, those having a deviation angle of 20 degrees or more and 50 degrees or less are more preferable. By setting the axial deviation angle between the polarizing film and the stretched polyethylene terephthalate film within the above range, color unevenness of the liquid crystal display device can be more effectively reduced.

In the stretched polyethylene terephthalate film of the present invention, any known technique can be used without limitation in order to control the Nz coefficient, the in-plane retardation value R ₀ and the slow axis within a specific range. Specifically, it can be controlled by adjusting stretching conditions such as stretching temperature, stretching ratio, relaxation treatment, and line speed during the above stretching treatment. In addition, the stretched polyethylene terephthalate film may often have distortions in the slow axis as represented by bowing, variations in the Nz coefficient, and R _{0 in} the width direction (perpendicular to the long direction). It can be seen. About such a stretched polyethylene terephthalate film, only the width range which has the target optical performance can also be selectively used as needed.

  Further, as a method of controlling the axial deviation angle between the transmission axis of the polarizing film and the slow axis of the stretched polyethylene terephthalate film in the polarizing plate of the present invention, the stretch direction and slow axis in the stretched polyethylene terephthalate film itself are the purpose. And a method of using only the width range having the desired optical performance as necessary as described above. When the latter method is employed, the polarizing film and the stretched polyethylene terephthalate film can be bonded by roll-to-roll, which is excellent in productivity and cost. Also, when laminating a stretched polyethylene terephthalate film to a polarizing film, adjust and paste so that the misalignment angle between the transmission axis direction of the polarizing film and the slow axis direction of the stretched polyethylene terephthalate film is within the target range. Also good.

  The stretched polyethylene terephthalate film used for the polarizing plate of the present invention preferably has a thickness in the range of 15 to 75 μm, and more preferably in the range of 20 to 60 μm. When the thickness of the stretched polyethylene terephthalate film is less than 15 μm, it tends to be difficult to handle (inferior in handleability), and when the thickness exceeds 75 μm, it becomes a thick film, resulting in high cost. The merit of thinning tends to fade.

  The stretched polyethylene terephthalate film thus obtained can be easily obtained as a commercial product. For example, “Diafoil”, “Hostafan”, “Fusion” (above, manufactured by Mitsubishi Plastics, Inc.) ), "Teijin Tetron Film", "Melinex", "Mylar", "Teflex" (Teijin DuPont Films Ltd.), "Toyobo Ester Film", "Toyobo Espet Film", "Cosmo Shine" “Chrisper” (manufactured by Toyobo Co., Ltd.), “Lumirror” (manufactured by Toray Film Processing Co., Ltd.), “Embron”, “Embret” (manufactured by Unitika Ltd.), “Skyroll” (SKC) Co., Ltd.), "Cofil" (manufactured by Kogo Co., Ltd.), "Zuitsu Polyester Film" (Co. Through, Ltd.), and "Taiko polyester film" (manufactured by Futamura Chemical Co., Ltd.), and the like. Among these, a uniaxially stretched product is preferably used from the viewpoint of efficiently imparting the optical performance necessary for the present invention, and from the viewpoints of productivity and inexpensiveness.

(Functional layer)
In the stretched polyethylene terephthalate film used in the present invention, when the film is used on the viewing side of the polarizing plate, an antiglare layer, a hard coat layer, a reflection is provided on the surface opposite to the surface on which the polarizing film is laminated. It is preferable to provide at least one functional layer selected from a prevention layer and an antistatic layer.

  The antiglare layer is provided in order to prevent reflection of external light and glare. The hard coat layer is provided to improve the scratch resistance of the surface. The antireflection layer is provided to prevent reflection of external light. The antistatic layer is provided to prevent the generation of static electricity. When these functional layers are formed on the polarizing plate of the present invention, they may be directly provided on a stretched polyethylene terephthalate film by a known method such as coating, or a film provided with these functional layers on a substrate is stretched. It may be bonded to a polyethylene terephthalate film. Further, a method in which these functional layers are formed in advance on a stretched polyethylene terephthalate film and this is bonded to the polarizing film on the surface opposite to the functional layer can also be employed.

  The anti-glare layer is, for example, a method in which an ultraviolet curable resin to which a filler is added is applied and then irradiated with ultraviolet rays to be cured to reveal irregularities based on the filler, and an embossed type is brought into contact with the ultraviolet curable resin. It can be provided by a method of irradiating with ultraviolet rays in the state of being cured and curing to reveal irregularities. The hard coat layer can be provided by a method of applying an ultraviolet curable hard coat resin and irradiating the hard coat resin with ultraviolet rays. The antireflection layer can be provided by a method in which a metal oxide or the like is deposited in a single layer or a plurality of layers. The antistatic layer can be provided by a method of applying an ultraviolet curable resin containing an antistatic agent and irradiating it with ultraviolet rays for curing. In general, a protective film having an easily peelable pressure-sensitive adhesive layer is bonded to the surface of the polarizing plate, and the surface is usually temporarily protected until use. An antistatic agent is blended in the pressure-sensitive adhesive layer constituting such a protective film, and it is also possible to paste it on the surface of a stretched polyethylene terephthalate film which is a transparent protective film of a polarizing plate. One.

  Furthermore, in the stretched polyethylene terephthalate film used in the present invention, various functional layers other than the above can be laminated on one side or both sides as long as the effects of the present invention are not hindered. Examples of the functional layer other than those described above include a conductive layer, a smoothing layer, an easy-sliding layer, an anti-blocking layer, and an easy-adhesion layer. Especially, since this stretched polyethylene terephthalate film is laminated | stacked through a polarizing film and an adhesive bond layer, it is preferable that the easily bonding layer is laminated | stacked.

  The component constituting the easy-adhesion layer is not particularly limited. For example, a polyester resin, a urethane resin, or an acrylic resin having a polar group in the skeleton and a relatively low molecular weight and a low glass transition temperature. Examples thereof include resins. Moreover, a crosslinking agent, an organic or inorganic filler, a surfactant, a lubricant and the like can be contained as necessary.

  The method of forming functional layers such as the conductive layer, smoothing layer, easy-sliding layer, anti-blocking layer, and easy-adhesion layer on the stretched polyethylene terephthalate film is not particularly limited. A method of forming a film after the process, a method of forming a polyethylene terephthalate-based resin, for example, a process of forming between a longitudinal stretching process and a lateral stretching process, and a process immediately before or after being bonded to a polarizing film The method to do is adopted. In the biaxially stretched polyethylene terephthalate film, a method in which a polyethylene terephthalate resin is formed after longitudinal stretching and then laterally stretched is preferably employed from the viewpoint of productivity.

(First adhesive layer)
In the polarizing plate of the present invention, the polarizing film and the stretched polyethylene terephthalate film are usually attached via a transparent and optically isotropic adhesive. Any of these adhesives can be used in consideration of adhesiveness to each film. Examples include polyvinyl alcohol adhesives, acrylic adhesives, urethane adhesives, epoxy adhesives, etc. In the present invention, an active energy ray-curable composition containing an alicyclic epoxy compound is employed. It is preferable to employ a solvent-free active energy ray-curable composition containing an alicyclic epoxy compound. By adopting such an adhesive, it becomes possible to improve the durability of the polarizing plate in a harsh environment, and when a solventless one is used, a step of drying the adhesive becomes unnecessary. Therefore, productivity can be improved. When an active energy ray-curable composition containing an alicyclic epoxy compound is used as an adhesive, after laminating a polarizing film and a stretched polyethylene terephthalate film via the adhesive, the active energy ray is irradiated to By curing the adhesive, a first adhesive layer composed of a cured product layer of the active energy ray curable composition is formed.

  Here, the alicyclic epoxy compound means one having an epoxy group directly in the ring of the saturated cyclic compound and one having a glycidyl ether group or glycidyl group directly in the ring of the saturated cyclic compound. In addition, you may have another epoxy group in the structure.

  An alicyclic epoxy compound having an epoxy group directly in the ring of a saturated cyclic compound is a base having a C—C double bond of a cyclic compound having a C—C double bond in the ring using a peroxide. It can be obtained by epoxidation under sexual conditions.

  The cyclic compound having a C—C double bond in the ring is not particularly limited, and examples thereof include a compound having a cyclopentene ring, a compound having a cyclohexene ring, and a polycyclic compound thereof. The cyclic compound having a C—C double bond in the ring may have a C—C double bond outside the ring. Examples of such a compound include 1-vinyl-3-cyclohexene and monocyclic ring. Examples include limonene, which is a formula monoterpene.

  Further, the alicyclic epoxy compound having an epoxy group directly on the ring of the saturated cyclic compound may be a compound having a structure obtained by dimerizing the epoxidized product obtained above through an appropriate functional group. The bond structure composed of the functional group is not particularly limited, and examples thereof include an ester bond, an ether bond, and a bond by an alkyl group. The dimerized structure of the epoxidized product may have a plurality of these bonds.

  The method for producing an alicyclic epoxy compound having an epoxy group directly on the ring of the saturated cyclic compound varies depending on the individual compound and is not particularly limited. After synthesizing a cyclic compound having a heavy bond in the ring, a method of epoxidizing, and a compound in which a C—C double bond is epoxidized are further reacted with a functional group as described above to obtain a target structure. A synthesis method or the like is employed. From the viewpoint of suppressing side reactions of epoxy groups and the like, usually, a method of epoxidizing after synthesizing a cyclic compound having a C—C double bond in the ring is preferably employed.

  The synthesis of a cyclic compound having a C—C double bond in the ring varies depending on the skeleton of the target epoxy compound and is not particularly limited. As a synthesis example of a dimerized cyclic compound, For example, a method of obtaining 3-cyclohexenylmethyl 3-cyclohexenecarboxylate, which is an ester compound, from 3-cyclohexene-1-carboxaldehyde by a Tishchenko reaction using an appropriate catalyst can be mentioned.

  Further, the ester compound and a dicarboxylic acid compound or an ester thereof, a diol compound or an ester thereof, a polyalkylene glycol or an ester thereof, or a hydroxycarboxylic acid compound or an ester thereof, if necessary, are subjected to an ester exchange reaction. By doing so, a compound having a cyclohexenyl group at both ends is obtained.

  Examples of dicarboxylic acid compounds and esters thereof include oxalic acid, adipic acid, sebacic acid, and dimethyl esters thereof. Examples of the diol compound and its ester include ethylene glycol, diethylene glycol, 1,2-propanediol, polyethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and dimethyl esters thereof. Can be mentioned. Examples of hydroxycarboxylic acid compounds and esters thereof include lactic acid, 3-hydroxybutyric acid, and citric acid, and dimethyl esters and acetates thereof, and lactide, propiolactone, butyrolactone, and caprolactone. .

  An alicyclic epoxy compound having an epoxy group directly in the ring of the saturated cyclic compound is obtained by epoxidizing the cyclic compound having the C—C double bond thus obtained with a peroxide. be able to. The peroxide is selected according to the individual cyclic compound and acceptable reaction conditions, and is not particularly limited. For example, hydrogen peroxide, peracetic acid, and t-butyl hydroperoxide are used. Etc.

  If the specific example of the alicyclic epoxy compound which has an epoxy group directly in the ring of the saturated cyclic compound preferably used in the adhesive which consists of an active energy ray hardening composition is mentioned, for example, 3, 4- epoxy cyclohexyl methyl 3,4-epoxycyclohexanecarboxylate, 1,2-epoxy-4-vinylcyclohexane, 1,2-epoxy-1-methyl-4- (1-methylepoxyethyl) cyclohexane, 3,4-epoxycyclohexylmethyl methacrylate 2- (1,2-epoxyethyl) -1,2-epoxycyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol, ethylene bis (3,4-epoxycyclohexanecarboxylate), oxydiethylene Bis (3,4-epoxycyclohexane Rubokishireto), 1,4-cyclohexane dimethyl bis (3,4-epoxycyclohexane carboxylate), and 3- (3,4-epoxycyclohexyl-methoxycarbonyl) propyl 3,4-epoxycyclohexane carboxylate and the like.

  An alicyclic epoxy compound having a glycidyl ether group or a glycidyl group directly on the ring of a saturated cyclic compound means that an aromatic ring of an aromatic compound having a hydroxyl group, which will be described later, is pressed under pressure in the presence of a catalyst. A compound obtained by selectively performing a hydrogenation reaction, a glycidyl etherified product of a saturated cyclic compound having a hydroxyl group, and an epoxidized product of a saturated cyclic compound having a vinyl group.

  The glycidyl etherified product of an aromatic compound having a hydroxyl group to be hydrogenated is not particularly limited, and examples thereof include glycidyl etherified products of bisphenol A and oligomers thereof, and glycidyl etherified products of bisphenol F and oligomers thereof. Examples include the body.

  The glycidyl etherified product of a saturated cyclic compound having a hydroxyl group is not particularly limited, and examples thereof include 1,4-cyclohexanedimethanol diglycidyl ether.

  The epoxidized product of the saturated cyclic compound having a vinyl group is not particularly limited. For example, 1,3-bis (epoxyethyl) hexane, 1,2,4-tris (epoxyethyl) hexane, and 2 , 4-bis (epoxyethyl) -1-vinylcyclohexane and the like.

  Among the alicyclic epoxy compounds described above, 3,4-epoxy has good cured product characteristics for improving the durability of the polarizing plate, or has moderate curability and is available at a relatively low price. A hydrogenated product of cyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and a glycidyl etherified product of bisphenol A is preferable, and 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate is more preferable.

  These alicyclic epoxy compounds may be used alone or in combination of two or more.

  Such alicyclic epoxy compounds can be easily obtained as commercial products. For example, “Celoxide”, “Cyclomer” (manufactured by Daicel Chemical Industries, Ltd.) and “ And “Syra Cure” (manufactured by Dow Chemical Co., Ltd.).

  In the adhesive composition containing such an alicyclic epoxy compound, an active energy ray-curable compound other than the alicyclic epoxy compound can be blended. As such an active energy ray-curable compound, an epoxy compound other than the alicyclic epoxy compound can be used. By using together an epoxy compound other than such an alicyclic epoxy compound, the adhesion between the polarizing film and the stretched polyethylene terephthalate film can be further improved.

  Examples of the epoxy compound other than the alicyclic epoxy compound include, but are not particularly limited to, for example, a glycidyl etherified product of an aromatic compound or a chain compound having a hydroxyl group, a glycidyl aminated product of a compound having an amino group, and C Examples thereof include epoxidized products of chain compounds having a -C double bond.

  The glycidyl etherified product of an aromatic compound or chain compound having a hydroxyl group is obtained by addition condensation of a compound such as epichlorohydrin to the hydroxyl group of the aromatic compound or chain compound under alkaline conditions. Examples thereof include bisphenol type epoxy resins, polyaromatic ring type epoxy resins, and alkylene glycol type epoxy resins.

  Examples of the bisphenol-type epoxy resin include glycidyl etherified products of bisphenol A and oligomers thereof, glycidyl etherified products of bisphenol F and oligomers thereof, and 3,3 ′, 5,5′-tetramethyl-4,4′- Examples thereof include glycidyl etherified products of biphenol and oligomers thereof.

  Examples of the polyaromatic epoxy resin include glycidyl etherified products of phenol novolac resins, glycidyl etherified products of cresol novolac resins, glycidyl etherified products of phenol aralkyl resins, glycidyl etherified products of naphthol aralkyl resins, and phenol dicyclopentadiene. Examples thereof include glycidyl etherified products of resins. Furthermore, a glycidyl etherified product of trihydroxyphenylmethane and an oligomer thereof, and a glycidyl etherified product of trisphenol PA and an oligomer thereof are also included.

  Examples of the alkylene glycol type epoxy resin include glycidyl etherified product of ethylene glycol, glycidyl etherified product of diethylene glycol, glycidyl etherified product of 1,4-butanediol, and glycidyl etherified product of 1,6-hexanediol. It is done.

  The glycidyl aminated product of a compound having an amino group is obtained by addition condensation of a compound such as epichlorohydrin to the amino group under basic conditions. The compound having an amino group may have a hydroxyl group at the same time. For example, glycidyl amination product of 1,3-phenylenediamine and oligomer thereof, glycidyl amination product and oligomer of 1,4-phenylenediamine, glycidyl amination and glycidyl etherification product of 3-aminophenol and oligomer thereof And glycidyl amination and glycidyl etherification products of 4-aminophenol and oligomers thereof.

  An epoxidized product of a chain compound having a CC double bond is an epoxidation of a CC compound of a chain compound having a CC double bond under basic conditions using a peroxide. It is obtained by making it.

  The chain compound having a C—C double bond is not particularly limited, and examples thereof include butadiene, polybutadiene, isoprene, pentadiene, and hexadiene.

  Epoxy compounds other than these alicyclic epoxy compounds and oligomers thereof may be used singly or in combination of two or more.

  Epoxy compounds other than such alicyclic epoxy compounds, oligomers thereof, and the like can be easily obtained from commercial products. For example, “Epicoat” (manufactured by Japan Epoxy Resin Co., Ltd.) under the trade name. , "Epiclon" (manufactured by DIC Corporation), "Epototo" (manufactured by Toto Kasei Corporation), "Adeka Resin" (manufactured by ADEKA Corporation), "Denacol" (manufactured by Nagase ChemteX Corporation), "Dow Epoxy" (Dow Chemical) And “Tepic” (manufactured by Nissan Chemical Industries, Ltd.).

  The epoxy equivalent of the epoxy compound other than the alicyclic epoxy compound and the alicyclic epoxy compound used in the adhesive composed of the active energy ray curable composition is usually 30 to 2000 g / eq, and 50 to 1500 g / eq. It is preferable that it is 70 to 1000 g / eq. When the epoxy equivalent is less than 30 g / eq, the flexibility of the first adhesive layer may be lowered or the adhesive strength may be lowered. On the other hand, if it exceeds 2000 g / eq, the curing rate may decrease, or the rigidity and strength required for the cured adhesive layer may be insufficient. This epoxy equivalent is a value measured according to JIS K 7236 (ISO 3001). If the epoxy compound is a high purity monomer, the theoretical amount can be calculated from the molecular weight.

  Moreover, an oxetane compound can also be used as an active energy ray-curable compound other than the alicyclic epoxy compound. By using the oxetane compound in combination, the curing rate of the active energy ray-curable composition can be improved. The oxetane compound is a compound having an oxetane ring and is not particularly limited as long as it is active energy ray curable. For example, 1,4-bis {[(3-ethyloxetane-3-yl) Methoxy] methyl} benzene, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, bis (3-ethyl-3-oxetanylmethyl) ether, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl -3- (cyclohexyloxymethyl) oxetane, phenol novolac oxetane, 1,3-bis [(3-ethyloxetane-3-yl) methoxy] benzene, and the like.

  Such oxetane compounds can be easily obtained from commercial products, for example, “Aron Oxetane” (manufactured by Toagosei Co., Ltd.) and “ETERRNACOLL” (manufactured by Ube Industries, Ltd.) under the trade names. Etc.

  The compounding ratio of the alicyclic epoxy compound in the active energy ray curable composition is a total of 100 parts by weight of the active energy ray curable compound (alicyclic epoxy compound, epoxy compound other than the alicyclic epoxy compound and oxetane compound). The alicyclic epoxy compound is preferably 30 to 95 parts by weight, more preferably 50 to 90 parts by weight, and even more preferably 70 to 85 parts by weight. When 30 parts by weight or more of the alicyclic epoxy compound is blended with respect to 100 parts by weight of the total amount of the active energy ray-curable compound, the durability of the polarizing plate adhered by the cured product of the active energy ray-curable composition is improved. There is an effect to. Moreover, when it exceeds 95 weight part, the toughness of a hardened | cured material layer may be inferior, or the cure rate of an active energy ray curable composition may fall.

  The active energy ray-curable composition containing an alicyclic epoxy compound used in the present invention is hardened (cured) by irradiation with active energy rays, and gives a bonding force between the films sandwiching the cured product layer. It is a thing. The active energy ray-curable composition containing an alicyclic epoxy compound is preferably blended with a cationic polymerization initiator in order to be cured by active energy rays.

  The cationic polymerization initiator generates a cationic species or a Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and initiates an epoxy group polymerization reaction. This cationic polymerization initiator is preferably provided with latency. By providing the potential, the pot life of the active energy ray-curable composition used in the present invention is prolonged, and the workability is also improved.

  The compound that generates a cationic species or a Lewis acid upon irradiation with active energy rays is not particularly limited. For example, an aromatic diazonium salt; an aromatic iodonium salt; an onium salt such as an aromatic sulfonium salt; and iron -An allene complex etc. can be mentioned.

  Examples of the aromatic diazonium salt include benzenediazonium hexafluoroantimonate, benzenediazonium hexafluorophosphate, and benzenediazonium hexafluoroborate.

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

  Examples of the aromatic sulfonium salt include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, diphenyl [4- (phenylthio) phenyl] sulfonium hexafluoroantimonate, 4,4′-bis [diphenylsulfonio] diphenyl sulfide bishexafluorophosphate, 4,4′-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenyl sulfide bishexafluoroantimonate, 4,4′-bis [Di (β-hydroxyethoxy) phenylsulfonio] diphenyl sulfide bishexafluorophosphate, 7- [di (p-toluyl) sulfoni ] -2-Isopropylthioxanthone hexafluoroantimonate, 7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate, 4-phenylcarbonyl-4'-diphenylsulfonio-diphenyl sulfide hexa Fluorophosphate, 4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfonio-diphenyl sulfide hexafluoroantimonate, and 4- (p-tert-butylphenylcarbonyl) -4'-di (p-toluyl) ) Sulfonio-diphenyl sulfide tetrakis (pentafluorophenyl) borate and the like.

  Examples of iron-allene complexes include xylene-cyclopentadienyl iron (II) hexafluoroantimonate, cumene-cyclopentadienyl iron (II) hexafluorophosphate, and xylene-cyclopentadienyl iron (II)- And tris (trifluoromethylsulfonyl) methanide.

  These cationic polymerization initiators may be used alone or in combination of two or more. Among them, aromatic sulfonium salts are particularly preferably used because they have ultraviolet absorption characteristics even in a wavelength region of 300 nm or more, and therefore can provide a cured layer having excellent curability and good mechanical strength and adhesive strength. .

  The compounding quantity of a cationic polymerization initiator is 0.5-20 weight part normally with respect to a total of 100 weight part of an active energy ray hardening compound, and 1-15 weight part is preferable. If the amount is less than 0.5 parts by weight, curing may be insufficient, and the mechanical strength and adhesive strength of the cured product layer may be reduced. On the other hand, when the amount exceeds 20 parts by weight, the ionic substance in the cured product layer is increased, so that the hygroscopic property of the cured product layer is increased, and the durability performance of the obtained polarizing plate may be lowered.

  These cationic polymerization initiators can be easily obtained from commercial products, for example, “Kayarad” (manufactured by Nippon Kayaku Co., Ltd.), “Syracure” (manufactured by Union Carbide), Photoacid generator “CPI” (manufactured by San Apro Co., Ltd.), photoacid generators “TAZ”, “BBI”, “DTS” (manufactured by Midori Chemical Co., Ltd.), “Adekaoptomer” (manufactured by ADEKA Corporation) And “RHODORSIL” (manufactured by Rhodia).

  The active energy ray-curable composition containing the alicyclic epoxy compound used in the present invention can be used in combination with a photosensitizer as necessary. By using a photosensitizer, the reactivity is improved, and the mechanical strength and adhesive strength of the cured product layer can be further improved.

  The photosensitizer is not particularly limited, and examples thereof include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, and photoreductive dyes. .

  Examples of the carbonyl compound include benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether, and α, α-dimethoxy-α-phenylacetophenone; anthracene compounds such as 9,10-dibutoxyanthracene; benzophenone, 2,4 Benzophenone derivatives such as -dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4'-bis (dimethylamino) benzophenone, and 4,4'-bis (diethylamino) benzophenone; of 2-chloroanthraquinone and 2-methylanthraquinone Anthraquinone derivatives such as; acridone derivatives such as N-methylacridone and N-butylacridone; acetophenone derivatives such as α, α-diethoxyacetophenone; And fluorenone derivatives.

  Examples of the organic sulfur compound include thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone. Other examples include benzyl compounds and uranyl compounds.

  The photosensitizers may be used alone or in combination. The photosensitizer is preferably contained in the range of 0.1 to 20 parts by weight when the active energy ray-curable composition is 100 parts by weight.

  Various additives can be blended with the active energy ray-curable composition used in the present invention as long as the effects of the present invention are not impaired. Examples of the various additives include ion trapping agents, antioxidants, chain transfer agents, tackifiers, thermoplastic resins, fillers, flow regulators, plasticizers, and antifoaming agents.

  Examples of the ion trapping agent include inorganic compounds such as powdered bismuth-based, antimony-based, magnesium-based, aluminum-based, calcium-based, titanium-based, and mixed systems thereof. Examples of the antioxidant include hindered phenol antioxidants.

  The total chlorine content contained in the active energy ray-curable composition containing the alicyclic epoxy compound used in the present invention is preferably in the range of 0.1 ppm to 15000 ppm, more preferably in the range of 0.5 ppm to 2000 ppm. A range of 0.0 to 1000 ppm is more preferable. If the total amount of chlorine contained in the active energy ray-curable composition is less than 0.1 ppm, the curing rate of the composition may be extremely slow. On the other hand, if it exceeds 15000 ppm, the coating device may corrode or the metal parts of the liquid crystal panel may corrode due to the influence of chlorine. This total chlorine amount is a value measured in accordance with JIS K 7243-3 (ISO 21627-3).

  The hue of the active energy ray-curable composition containing the alicyclic epoxy compound used in the present invention is preferably 5 or less, more preferably 3 or less in terms of Gardner chromaticity of the active energy ray-curable composition before curing. The following is more preferable. When the hue exceeds 5, the hue of the polarizing plate may be affected by the coloring of the adhesive layer.

  The method of forming the adhesive layer (adhesive layer before curing) comprising the active energy ray-curable composition shown above on the polarizing film or the stretched polyethylene terephthalate film is not particularly limited. A method of coating the composition on a polarizing film or a stretched polyethylene terephthalate film, a method of spraying the composition, a method of pasting the composition formed into a film in advance, and the like are employed. Among them, the method of applying the composition or the method of pasting the film-like composition is preferable because of relatively high uniformity of the coating film, and the method of applying the composition is more highly productive. preferable.

  Although it does not specifically limit as a coating method, For example, various coating systems, such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater, are employ | adopted.

  The thickness of the applied adhesive layer before curing is usually 0.1 to 20 μm, preferably 0.2 to 10 μm, and more preferably 0.5 to 5 μm. If the thickness is less than 0.1 μm, the adhesion between the polarizing film and the stretched polyethylene terephthalate film due to the cured adhesive layer may be insufficient. Further, if the thickness exceeds 20 μm, the curing of the adhesive layer may not proceed sufficiently, or even if cured, the flexibility of the film may deteriorate due to the thickness, or the effect of thinning may not be obtained. .

  The polarizing plate of the present invention can be obtained by irradiating an active energy ray to the laminate of the polarizing film and the stretched polyethylene terephthalate film laminated via the adhesive layer and curing the adhesive layer. .

  Examples of the active energy ray used include X-rays having a wavelength of 1 pm to 10 nm, ultraviolet rays having a wavelength of 10 to 400 nm, and visible rays having a wavelength of 400 to 800 nm. Among these, ultraviolet rays are preferably used in terms of ease of use, ease of preparation of the active energy ray-curable composition and its stability, and its curing performance.

  Although the light source to be used is not particularly limited, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, having a light emission distribution at a wavelength of 400 nm or less, And metal halide lamps.

The irradiation intensity is determined by the active energy ray-curable composition and the irradiation time, and is not particularly limited. For example, the irradiation intensity in the wavelength region effective for activating the initiator is 0.1. It is preferable that it is -1000mW / cm < ² >. When the light irradiation intensity to the active energy ray-curable composition is less than 0.1 mW / cm ² , the curing reaction time becomes long, that is, it does not cure unless a long irradiation time is applied, which is disadvantageous for improving productivity. There is a case. Moreover, when it exceeds 1000 mW / cm ² , yellowing of the active energy ray-curable composition or deterioration of the polarizing film is caused by heat radiated from the lamp and heat generation during polymerization of the active energy ray-curable composition. There is.

The irradiation time is determined by the active energy ray-curable composition and the irradiation intensity and is not particularly limited. For example, the integrated light amount expressed as the product of the irradiation intensity and the irradiation time is 10 to 5 It is preferably set to be 000 mJ / cm ² . When the integrated light amount to the active energy ray-curable composition is less than 10 mJ / cm ² , the generation of active species derived from the initiator is not sufficient, and the resulting adhesive layer may be insufficiently cured. On the other hand, if it exceeds 5,000 mJ / cm ² , the irradiation time becomes very long, which may be disadvantageous for improving productivity.

(Protective film, optical compensation film)
The polarizing plate of the present invention may include a protective film or an optical compensation film laminated via a second adhesive layer on the surface of the polarizing film opposite to the surface on which the stretched polyethylene terephthalate film is laminated. Good.

  The protective film or the optical compensation film can be appropriately used in accordance with the purpose as long as it has an optical property as an optical film, and is not particularly limited, but examples of the protective film include triacetyl cellulose (TAC). Or the like, and those composed of transparent resin films such as cellulose resin films, olefin resin films, acrylic resin films, polycarbonate resin films, and polyester resin films.

  Specific examples of the optical compensation film include those obtained by stretching the transparent resin film to give refractive index anisotropy, those containing an optical anisotropy imparting additive, and an optical anisotropic layer on the surface. And the like formed.

  The protective film or the optical compensation film may be laminated with an optical functional film or coated with an optical functional layer, as will be described later.

  The cellulose resin film is a film made of a part of cellulose or a completely esterified product, and examples thereof include films made of cellulose acetate ester, propionate ester, butyrate ester, and mixed esters thereof. Among these, a triacetyl cellulose film, a diacetyl cellulose film, a cellulose acetate propionate film, a cellulose acetate butyrate film, and the like are preferably used.

  Such cellulose-based resin films can be easily obtained as commercial products. For example, “Fujitac TD” (manufactured by Fuji Film Co., Ltd.) and “Konica Minolta TAC Film KC” ( Konica Minolta Opto Co., Ltd.).

  The olefin resin film is a film made of a resin obtained by polymerizing a chain olefin monomer such as ethylene and propylene, or a cyclic olefin monomer such as norbornene and other cyclopentadiene derivatives using a polymerization catalyst. is there.

  Examples of the olefin resin made of a chain olefin monomer include polyethylene or polypropylene resin. Among these, a polypropylene resin made of a homopolymer of propylene is preferable. Also preferred is a polypropylene resin in which a comonomer mainly composed of propylene and copolymerizable with it is usually copolymerized at a ratio of 1 to 20% by weight, preferably 3 to 10% by weight.

  When a polypropylene resin made of a propylene copolymer is used, the comonomer copolymerizable with propylene is preferably ethylene, 1-butene, or 1-hexene. Among these, those obtained by copolymerizing ethylene at a ratio of 3 to 10% by weight are preferable because of relatively excellent transparency and stretchability. By making the copolymerization ratio of ethylene 1% by weight or more, an effect of improving transparency and stretch processability appears. On the other hand, when the ratio exceeds 20% by weight, the melting point of the resin is lowered, and the heat resistance required for the protective film and the optical compensation film may be impaired.

  Such polypropylene-based resins can be easily obtained from commercial products. For example, “Prime Polypro” (manufactured by Prime Polymer Co., Ltd.), “Novatech”, “Wintech” (above) , Manufactured by Nippon Polypro Co., Ltd.), “Sumitomo Noblen” (manufactured by Sumitomo Chemical Co., Ltd.), “Sun Aroma” (manufactured by Sun Aroma Co., Ltd.)

  An olefin resin obtained by polymerizing a cyclic olefin monomer is generally referred to as a cyclic (poly) olefin resin, an alicyclic (poly) olefin resin, or a norbornene resin. Here, it is called a cyclic olefin resin.

  Examples of the cyclic olefin-based resin include a resin obtained by performing ring-opening metathesis polymerization from cyclopentadiene and olefins using norbornene obtained by Diels-Alder reaction or a derivative thereof as a monomer, followed by hydrogenation; dicyclopentadiene and Resins obtained by ring-opening metathesis polymerization from olefins or methacrylic acid esters using tetracyclododecene or its derivatives obtained by Diels-Alder reaction as monomers, followed by hydrogenation; norbornene, tetracyclododecene, etc. Similarly, a ring-opening metathesis copolymerization with other cyclic olefin monomers and a resin obtained by subsequent hydrogenation; and norbornene, tetracyclododecene, Derivatives of al, and resins obtained by copolymerizing by addition polymerization of aromatic compounds and the like having a vinyl group.

  Such a cyclic olefin-based resin can be easily obtained as a commercial product. For example, under the trade name, “Topas” (Topas Advanced Polymers GmbH), “Arton” (manufactured by JSR Corporation), “Zeonor”, “Zeonex” (manufactured by Nippon Zeon Co., Ltd.), “Appel” (manufactured by Mitsui Chemicals, Inc.), and the like.

  Preferable specific examples of the acrylic resin film include a film made of methyl methacrylate resin. The methyl methacrylate resin is a polymer containing 50% by weight or more of methyl methacrylate units. The content of methyl methacrylate units is preferably 70% by weight or more, and may be 100% by weight. The polymer having a methyl methacrylate unit of 100% by weight is a methyl methacrylate homopolymer obtained by polymerizing methyl methacrylate alone.

  This methyl methacrylate-based resin is usually a monofunctional monomer mainly composed of methyl methacrylate and a polyfunctional monomer used as necessary, as a radical polymerization initiator and as required. It can be obtained by polymerization in the presence of a chain transfer agent.

  The monofunctional monomer that can be copolymerized with methyl methacrylate is not particularly limited. For example, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, methacrylic acid 2 -Methacrylic acid esters other than methyl methacrylate such as ethylhexyl and 2-hydroxyethyl methacrylate; methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-acrylate Acrylic esters such as ethylhexyl and 2-hydroxyethyl acrylate; methyl 2- (hydroxymethyl) acrylate, methyl 3- (hydroxyethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate And hydroxyacrylic esters such as 2- (hydroxymethyl) butyl acrylate; unsaturated acids such as methacrylic acid and acrylic acid; halogenated styrenes such as chlorostyrene and bromostyrene; vinyltoluene and α-methylstyrene Substituted styrenes; unsaturated nitriles such as acrylonitrile and methacrylonitrile; unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride; and unsaturated imides such as phenylmaleimide and cyclohexylmaleimide it can. Such monomers may be used alone or in combination of two or more.

  The polyfunctional monomer that can be copolymerized with methyl methacrylate is not particularly limited. For example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate , Ethylene glycol such as tetraethylene glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, and tetradecaethylene glycol (meth) acrylate, or both terminal hydroxyl groups of oligomers thereof esterified with acrylic acid or methacrylic acid ; Hydroxyl or methacrylic acid esterified at both terminal hydroxyl groups of propylene glycol or its oligomer; Neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate Lilate and hydroxyl group of dihydric alcohol such as butanediol di (meth) acrylate esterified with acrylic acid or methacrylic acid; Bisphenol A, alkylene oxide adduct of bisphenol A, or both terminal hydroxyl groups of these halogen-substituted products Esterified with acrylic acid or methacrylic acid; polyhydric alcohols such as trimethylolpropane and pentaerythritol esterified with acrylic acid or methacrylic acid, and the epoxy group of glycidyl acrylate or glycidyl methacrylate opened at the terminal hydroxyl groups Cyclic addition: Dibasic acids such as succinic acid, adipic acid, terephthalic acid, phthalic acid, halogen-substituted products thereof, and alkylene oxide adducts thereof. Those with an epoxy group of bets or glycidyl methacrylate by ring-opening addition; aryl (meth) acrylate; and diaryl compounds such as divinylbenzene, and the like. Among these, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and neopentyl glycol dimethacrylate are preferably used.

  The methyl methacrylate resin may be a modified methyl methacrylate resin modified by a reaction between functional groups of the resin. As the reaction, for example, demethanol condensation reaction in a polymer chain between a methyl ester group of methyl acrylate and a hydroxyl group of 2- (hydroxymethyl) methyl acrylate, and a carboxyl group of acrylic acid and 2- (hydroxymethyl) ) Intrapolymer dehydration condensation reaction with hydroxyl group of methyl acrylate.

  Commercially available methyl methacrylate resins can be easily obtained. For example, “Sumipex” (manufactured by Sumitomo Chemical Co., Ltd.), “Acrypet” (manufactured by Mitsubishi Rayon Co., Ltd.), “Delpet” (manufactured by Asahi Kasei Co., Ltd.), “parapet” (manufactured by Kuraray Co., Ltd.), “Acryviewer” (manufactured by Nippon Shokubai Co., Ltd.)

  The polycarbonate resin constituting the polycarbonate resin film is usually obtained by reacting a dihydric phenol and a carbonate precursor such as phosgene or diphenyl carbonate by an interfacial polycondensation method or a melt transesterification method. An aromatic polycarbonate resin using bisphenol A as a dihydric phenol is common. In addition, a polymer obtained by polymerizing a carbonate prepolymer by a solid phase transesterification method, a polymer obtained by subjecting a cyclic carbonate compound to ring-opening polymerization, or the like can also be used.

  The dihydric phenol is not particularly limited as long as it does not impair the performance as an optical transparent resin. For example, in addition to bisphenol A (2,2-bis (4-hydroxyphenyl) propane) , Hydroquinone, resorcinol, 4,4′-dihydroxydiphenyl, bis (4-hydroxyphenyl) methane, bis {(4-hydroxy-3,5-dimethyl) phenyl} methane, 1,1-bis (4-hydroxyphenyl) Ethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -4-isopropylcyclohexane, 2 , 2-bis {(4-hydroxy-3-methyl) phenyl} propane, 2,2-bis {(4 Hydroxy-3,5-dimethyl) phenyl} propane, 2,2-bis {(4-hydroxy-3,5-dibromo) phenyl} propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2- Bis (4-hydroxyphenyl) -3-methylbutane, 2,4-bis (4-hydroxyphenyl) -2-methylbutane, 2,2-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxy) Phenyl) -4-methylpentane, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis {(4-hydroxy-3-methyl) phenyl} fluorene, 9,9-bis {(4-hydroxy) −3,5-dimethyl) phenyl} fluorene, 9,9-bis {(4-hydroxy-3,5-dibromo) phenyl} fluorene, α, α′-bis ( -Hydroxyphenyl) -o-diisopropylbenzene, α, α'-bis (4-hydroxyphenyl) -m-diisopropylbenzene, α, α'-bis (4-hydroxyphenyl) -p-diisopropylbenzene, 4,4 ' -Dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl ketone, 4,4'-dihydroxydiphenyl ether and the like can be mentioned, and these can be used alone or in admixture of two or more.

  Moreover, a monohydric phenol compound may be used in combination to adjust the molecular weight to an appropriate range or to seal the hydroxyl terminal of the polymer chain. The monohydric phenol is not particularly limited as long as it is a compound that functions as a terminal blocking agent. For example, phenol, 4-tert-butylphenol, and 1-phenyl-1- (4-hydroxyphenyl) Examples include propane.

  Further, if necessary, a compound having UV absorbability such as 2- (2-hydroxy-3-tert-butyl-5- (2-carboxyethyl)) phenylbenzotriazole can be used as a terminal blocking agent. .

  Polycarbonate resins can be easily obtained as commercial products. For example, “Lexan” (manufactured by SABIC Innovative Plastics), “Macrolon”, “Apec” (above, Bayer MaterialScience) "Iupilon", "Novax" (Mitsubishi Engineering Plastics Co., Ltd.), "Panlite" (manufactured by Teijin Chemicals Ltd.), "Caliber" (Dow Chemical Co., Ltd.), "SD Polyca" ( Sumitomo Dow Co., Ltd.) and “Toughlon” (Idemitsu Kosan Co., Ltd.).

  As a method for molding the chain olefin resin, the cyclic olefin resin, the methyl methacrylate resin, the polycarbonate resin, and the like thus obtained into a protective film, a method corresponding to the resin may be appropriately selected. It is not limited. For example, a resin dissolved in a solvent is cast onto a metallic band or drum, and the solvent is cast by removing the solvent by drying, and the resin is heated and kneaded above its melting temperature and extruded from a die, A melt extrusion method for obtaining a film by cooling is employed. Of these, the melt extrusion method is preferably employed from the viewpoint of productivity.

  Moreover, the film which consists of the said resin which can be used as a protective film can obtain a commercial item easily, for example, if it is a polypropylene-type resin film, a brand name will be "FILMAX CPP film" (FILMAX company), respectively. ), "Santox" (manufactured by Santox Corporation), "Tosero" (manufactured by Tosero Co., Ltd.), "Toyobo Pyrene Film" (manufactured by Toyobo Co., Ltd.), "Trephan" (manufactured by Toray Film Processing Co., Ltd. ), “Nihon Polyace” (manufactured by Nippon Polyace Corporation), “Dazai FC” (manufactured by Futamura Chemical Co., Ltd.), and the like.

  Further, for example, in the case of a cyclic olefin-based resin film, “ZEONOR FILM” (manufactured by Optes Co., Ltd.), “ARTON FILM” (manufactured by JSR Corporation), and the like are listed under the trade names.

  In addition, for example, for methyl methacrylate resin films, “Sumipex” (manufactured by Sumitomo Chemical Co., Ltd.), “Acrylite”, “Acryprene” (above, manufactured by Mitsubishi Rayon Co., Ltd.), “Delagrass” ( Asahi Kasei Co., Ltd.), “Paragrass”, “Comograss” (manufactured by Kuraray Co., Ltd.), “Acryviewer” (manufactured by Nippon Shokubai Co., Ltd.), and the like.

  In addition, for example, for polycarbonate resin films, “Lexan OQ Film” (manufactured by SABIC Innovative Plastics), “Macro Hall”, “Bihole” (above, Bayer MaterialScience), “Iupilon Sheet” "(Mitsubishi Engineering Plastics Co., Ltd.)" and "Panlite Sheet" (Teijin Chemicals Co., Ltd.).

  Moreover, as the polyester-based resin film that can be used as a protective film provided on the opposite side of the polarizing film from the side on which the stretched polyethylene terephthalate film is laminated, the stretched polyethylene terephthalate film is used. The same type of polyester resin (polyethylene terephthalate resin) can be used. In this case, an unstretched polyester resin film is used, and for example, the film obtained by the melt extrusion can be used as it is.

  Unstretched polyester resin films that can be used as protective films can be easily obtained as commercial products. For example, “Novaclear” (manufactured by Mitsubishi Chemical Corporation) and “Teijin A” under the trade names, respectively. -PET sheet "(manufactured by Teijin Chemicals Ltd.) and the like.

  In addition, the optical compensation film made of a cellulose resin film is not particularly limited as long as it has a refractive index characteristic suitable for the purpose. For example, the cellulose resin film mentioned above is uniaxial or biaxial. A film obtained by stretching, or a film in which a compound having a retardation adjusting function is contained in a cellulose resin film, a film in which a compound having a retardation adjusting function is applied to the surface of a cellulose resin film, and those films, Furthermore, the film etc. which are obtained by uniaxial or biaxial stretching are mentioned.

  The optical compensation film made of a cellulose resin film can be easily obtained as a commercial product. For example, “Fujitack WV” (manufactured by FUJIFILM Corporation) and “Konica Minolta TAC Film KC8UCR” are available under the trade names. (Made by Konica Minolta Opto Co., Ltd.).

  Moreover, in order to use the olefin resin film, the acrylic resin film, the polycarbonate resin film, the polyester resin film, and the like exemplified as the protective film as an optical compensation film, the unstretched film is usually stretched, Give the film refractive index anisotropy. The stretching method is selected according to the required refractive index anisotropy and is not particularly limited. Usually, however, the longitudinal uniaxial stretching, the transverse uniaxial stretching, and the longitudinal and transverse sequential biaxial stretching are performed. Is adopted.

Usually, was longitudinally uniaxially stretched film has a refractive index anisotropy of _{n x> n y = n z} . Here, n _x is the refractive index in the stretching direction of the film, n _y is a refractive index in the width direction of the film, n _z is the normal direction refractive index of the film.

Also, usually, is transverse uniaxially stretched film has a refractive index anisotropy of _{n x> n y ≒ n z} . Also, typically, it has been sequentially biaxially-oriented film has a refractive index anisotropy of _{n x> n y> n z} .

Moreover, in order to provide a desired refractive index characteristic, a heat-shrinkable film is bonded to a target film, and the film is contracted instead of or along with the stretching process. Usually, this operation is performed in order to obtain an optical compensation film having a refractive index anisotropy is n _x> n _z> n _y or _{n z> n x ≧ n y} .

These optical compensation film, when the thickness was d, plane retardation value R ₀ is at the _{(n x -n y) × d} , the retardation value R _th in the thickness direction _{[(n x + n y)} / 2 −n _z ] × d, respectively.

  As the optical compensation film, a commercially available product can be easily obtained. For example, as an optical compensation film comprising a cyclic polyolefin resin, “ZEONOR FILM” (manufactured by Optes Co., Ltd.), “ARTON” “Film” (manufactured by JSR Corporation), “Essina retardation film” (manufactured by Sekisui Chemical Co., Ltd.), “Pure Ace ER” (manufactured by Teijin Chemicals Ltd.), and the like. Examples of the optical compensation film made of a polycarbonate-based resin include “Pure Ace WR” (manufactured by Teijin Chemicals Ltd.).

  Furthermore, an optical functional film can be laminated or an optical functional layer can be coated on the protective film or the optical compensation film laminated on the polarizing film via the second adhesive layer. Examples of the optical functional film and the optical functional layer include an antiglare layer, a conductive layer, a hard coat layer, and an antireflection layer.

(Second adhesive layer)
In the polarizing plate of the present invention, the polarizing film and the protective film or the optical compensation film are usually attached via a transparent and optically isotropic second adhesive. Any of these adhesives can be used in consideration of adhesiveness to each film. Examples include polyvinyl alcohol adhesives, acrylic adhesives, urethane adhesives, epoxy adhesives, etc. In the present invention, as with the adhesive forming the first adhesive layer, an alicyclic ring is used. It is preferable to employ an active energy ray-curable composition containing a formula epoxy compound, and it is more preferred to employ a solventless active energy ray-curable composition containing an alicyclic epoxy compound. In this case, the 2nd adhesive bond layer interposed between a polarizing film and a protective film or an optical compensation film consists of the hardened | cured material layer of the said active energy ray curable composition. If the same composition as the active energy ray-curable composition that forms the first adhesive layer is used as the active energy ray-curable composition that forms the second adhesive layer, only one type of adhesive is required. Therefore, the process becomes simple, and when a solvent-free one is used, drying of the adhesive becomes unnecessary, so that a drying facility after pasting the protective film or the optical compensation film becomes unnecessary, Since the stretched polyethylene terephthalate film and the protective film or the optical compensation film arranged on both sides of the polarizing film can be simultaneously bonded by in-line active energy ray irradiation at the time of producing the polarizing plate, there is an advantage that productivity is improved.

  In addition, as an adhesive forming the second adhesive layer, for example, a water-based adhesive used when bonding a polarizing film and a protective film made of a TAC film may be used. Examples of the adhesive component that can be a water-based adhesive include a water-soluble crosslinkable epoxy resin and a urethane resin.

  As a water-soluble crosslinkable epoxy resin, for example, a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine and a polyamide polyamine obtained by a reaction of a dicarboxylic acid such as adipic acid are reacted with epichlorohydrin. The polyamide epoxy resin obtained is mentioned.

  Such a polyamide epoxy resin is commercially available. For example, “Smileys Resin 650” and “Smileys Resin 675” (sold by Sumika Chemtex Co., Ltd.) are listed as trade names. It is done.

  When a water-soluble crosslinkable epoxy resin is used as the adhesive component, it is preferable to mix other water-soluble resins such as a polyvinyl alcohol-based resin in order to further improve coatability and adhesiveness. Polyvinyl alcohol resins are modified such as partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, as well as carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol. Polyvinyl alcohol resin may be used.

  Such a polyvinyl alcohol-based resin can be obtained as a commercial product. For example, for an anionic group-containing polyvinyl alcohol, “KL-318” (manufactured by Kuraray Co., Ltd.) can be given as a trade name.

  When an adhesive containing a water-soluble crosslinkable epoxy resin is used, an adhesive solution is prepared by dissolving the crosslinkable epoxy resin and other water-soluble resins such as a polyvinyl alcohol resin added as necessary in water. Configure. In this case, the water-soluble crosslinkable epoxy resin is usually used at a concentration in the range of 0.2 to 2 parts by weight per 100 parts by weight of water.

  Moreover, when mix | blending polyvinyl alcohol-type resin, the quantity is the density | concentration of the range of 1-10 weight part per 100 weight part of water, and 1-5 weight part is preferable.

  On the other hand, when a water-based adhesive containing a urethane resin is used, examples of suitable urethane resins include ionomer-type urethane resins, particularly polyester-based ionomer-type urethane resins. Here, the ionomer type is obtained by introducing a small amount of an ionic component (hydrophilic component) into the urethane resin constituting the skeleton. The polyester ionomer type urethane resin is a urethane resin having a polyester skeleton, into which a small amount of an ionic component (hydrophilic component) is introduced.

  Such an ionomer-type urethane resin is suitable as a water-based adhesive because it is emulsified directly in water without using an emulsifier and becomes an emulsion.

  Such an ionomer type urethane resin can be easily obtained as a commercial product of an emulsion, and examples thereof include “Hydran AP-20” and “Hydran APX-101H” (manufactured by DIC Corporation).

  When an ionomer type urethane resin is used as an adhesive component, it is preferable to further add a crosslinking agent such as an isocyanate. The isocyanate-based crosslinking agent is a compound having at least two isocyanato groups (—NCO) in the molecule. Examples thereof include 2,4-tolylene diisocyanate, phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 1, Examples thereof include monomers such as 6-hexamethylene diisocyanate and isophorone diisocyanate, oligomers thereof, and adducts obtained by reacting these compounds with polyols.

  Such an isocyanate-based crosslinking agent can be easily obtained as a commercial product, and examples thereof include “Hydran Assist C-1” (manufactured by DIC Corporation).

  When an aqueous adhesive containing an ionomer type urethane resin is used, the concentration of the urethane resin dispersed in water is usually 10 to 70% by weight and preferably 20 to 50% by weight from the viewpoints of viscosity and adhesiveness. .

  When mix | blending an isocyanate type crosslinking agent, the compounding quantity is 5-100 weight part of isocyanate type crosslinking agents with respect to 100 weight part of urethane resins normally.

  The polarizing plate of the present invention can be obtained by applying the aqueous adhesive as described above to the protective film, the optical compensation film, or the adhesive surface of the polarizing film and bonding them together. Prior to bonding, it is also effective to increase the wettability by subjecting the surface of the protective film or the optical compensation film to easy adhesion treatment such as corona discharge treatment.

  In the case of adhesion using such an aqueous adhesive, a drying treatment is usually performed at a temperature of about 30 to 100 ° C. after lamination. Thereafter, it is preferable to perform curing for about 1 to 10 days at a temperature of about 20 to 50 ° C. in order to further increase the adhesive force.

(Adhesive layer)
The polarizing plate of the present invention can have an adhesive layer on the outer side of the protective film or the optical compensation film (the surface opposite to the surface on which the polarizing film in the protective film or the optical compensation film is laminated). Such an adhesive layer can be used for bonding with a liquid crystal cell.

  The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is not particularly limited as long as it satisfies various properties (transparency, durability, reworkability, etc.) used in the optical film. For example, (meth) acrylic acid ester The glass transition temperature (Tg) is 0 ° C., which is obtained by radical polymerization of an acrylic monomer composition containing a main component and a small amount of a (meth) acrylic monomer having a functional group in the presence of a polymerization initiator. An acrylic pressure-sensitive adhesive containing the following acrylic resin and a crosslinking agent is used.

Here, the (meth) acrylic acid ester as the main component of the acrylic resin has the following formula:
CH ₂ = C (R ¹ ) COOR ²
In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkyl group having 1 to 14 carbon atoms or an aralkyl group, and a hydrogen atom or an aralkyl group of the alkyl group represented by R ^2. The hydrogen atom may be substituted with an alkoxy group having 1 to 10 carbon atoms.

  In addition, the (meth) acrylic monomer having a functional group has a polar functional group such as a hydroxyl group, a carboxyl group, an amino group, and an epoxy group and one olefinic double bond (usually a (meth) acryloyl group) in the molecule. It is a monomer to contain.

As a specific example of the main component of the acrylic resin (meth) acrylic acid esters, for example, R ¹ is H, butyl acrylate and R ² are n- butyl group, R ¹ is H And ² -ethylhexyl acrylate in which R ² is a 2-ethylhexyl group. Specific examples of the (meth) acrylic monomer having a functional group include, for example, 2-hydroxyethyl (meth) acrylate having a hydroxyl group; acrylic acid having a carboxyl group. Furthermore, in the production of this acrylic resin, a small amount of monomers having a plurality of (meth) acryloyl groups in the molecule can be copolymerized, and examples thereof include 1,4-butanediol di (meth) acrylate. It is done.

  In the production of the acrylic resin, only one type of the (meth) acrylic acid ester and the (meth) acrylic monomer having a functional group may be used, or a plurality of types may be used in combination. In addition, a combination of a plurality of acrylic resins that are copolymers of (meth) acrylic acid esters and (meth) acrylic monomers having functional groups, or other acrylic resins in addition to the acrylic resins that are the copolymers. For example, an acrylic resin composition obtained by blending, for example, an acrylic resin composed of a single or copolymer of a (meth) acrylic monomer having no functional group, can be used as the resin component of the pressure-sensitive adhesive.

  The weight average molecular weight of the acrylic resin contained in the acrylic pressure-sensitive adhesive is usually about 600,000 to 2,000,000 in terms of standard polystyrene using gel permeation chromatography (GPC), and 800,000 to 1,800,000. Is preferred. If the weight average molecular weight is less than 600,000, the tackiness and durability may be lowered. Moreover, when the weight average molecular weight exceeds 2 million, the pressure-sensitive adhesive layer becomes harder than necessary, and it becomes difficult to peel off after adhesion, or undesired stress birefringence is applied to the protective film or optical compensation film to be bonded. There is a case to give.

  The crosslinking agent blended in the acrylic pressure-sensitive adhesive can be an isocyanate compound, an epoxy compound, a metal chelate compound, an aziridine compound, or the like. Isocyanate compounds should be used in the form of adducts obtained by reacting them with polyols, dimers and trimers in addition to compounds having at least two isocyanato groups (-NCO) in the molecule. Can do. As specific examples of the crosslinking agent, there are a trimethylolpropane adduct of hexamethylene diisocyanate and a trimethylolpropane adduct of tolylene diisocyanate as diisocyanate compounds, each used as a solution dissolved in an organic solvent such as ethyl acetate. There are many cases. These crosslinking agents may be used alone or in combination of two or more.

  The acrylic resin is dissolved in an organic solvent such as ethyl acetate, and a crosslinking agent is added to obtain an acrylic pressure-sensitive adhesive solution. Further, if necessary, one or more of silane coupling agents, weathering stabilizers, tackifiers, plasticizers, softeners, pigments, and inorganic fillers, and further light diffusing fine particles such as organic beads are included. be able to.

  The acrylic pressure-sensitive adhesive solution thus obtained is usually coated on a release film, heated at 60 to 120 ° C. for about 0.5 to 10 minutes, and the organic solvent is distilled off to form a pressure-sensitive adhesive layer. . Next, after the protective film or the optical compensation film is bonded to the pressure-sensitive adhesive layer, it is aged for about 5 to 20 days in an atmosphere of a temperature of 23 ° C. and a humidity of 65%, for example, and the crosslinking agent is sufficiently reacted.

  Moreover, after forming an adhesive layer on a peeling film, a peeling film is further bonded and the adhesive layer single sheet which cannot be supported by base materials, such as a protective film, can also be obtained. Also in this case, after the release film is bonded, for example, in an atmosphere of a temperature of 23 ° C. and a humidity of 65%, the film is aged for about 5 to 20 days to sufficiently react the crosslinking agent. In the production of a protective film or an optical compensation film, such a pressure-sensitive adhesive sheet is used by peeling the release film on one side and bonding it to the protective film or the optical compensation film at a necessary time.

  The raw materials for the acrylic pressure-sensitive adhesive as described above can be easily obtained as commercial products, for example, various acrylic monomers (manufactured by Nippon Shokubai Co., Ltd., manufactured by Toagosei Co., Ltd.), polymerization initiator 2 , 2'-azobisisobutyronitrile, etc. (manufactured by Otsuka Kagaku Co., Ltd., Nihon Finechem Co., Ltd.), hexamethylene diisocyanate as a crosslinking agent, and trimethylolpropane adducts thereof, tolylene diisocyanate, and trimethylolpropane thereof Examples thereof include adduct bodies (Mitsui Chemicals Polyurethane Co., Ltd., Sumika Bayer Urethane Co., Ltd.).

  There are also commercially available pressure-sensitive adhesive sheets such as “non-carrier pressure-sensitive adhesive film / sheet” (manufactured by Lintec Corporation, manufactured by Nitto Denko Corporation).

<Liquid crystal display device>
The polarizing plate formed as described above, that is, stretched polyethylene terephthalate film / first adhesive layer / polarizing film / second adhesive layer / [protective film or optical compensation film] / adhesive layer / release film A polarizing plate having a layer structure can be a liquid crystal panel by peeling off a release film from an adhesive layer and bonding it to one or both sides of a liquid crystal cell. This liquid crystal panel can be applied to a liquid crystal display device.

  The polarizing plate of the present invention can be used, for example, as a polarizing plate disposed on the light emitting side (viewing side) in a liquid crystal display device. The light emitting side refers to the side opposite to the backlight side of the liquid crystal display device based on the liquid crystal cell. When the polarizing plate of the present invention is adopted as the polarizing plate on the light emission side, the polarizing plate has an antiglare layer and a hard coat on the surface opposite to the surface on which the polarizing film in the stretched polyethylene terephthalate film is laminated. It is preferable to include at least one functional layer selected from a layer, an antireflection layer, and an antistatic layer. The polarizing plate disposed on the light incident side (backlight side) of the liquid crystal display device may be the polarizing plate of the present invention or a conventionally known polarizing plate.

  The polarizing plate of the present invention can also be used as a polarizing plate disposed on the light incident side in a liquid crystal display device. In this case, the polarizing plate disposed on the light emitting side of the liquid crystal display device may be the polarizing plate of the present invention or a conventionally known polarizing plate.

  A liquid crystal cell constituting a liquid crystal display device is a member in which liquid crystal is sealed between two transparent substrates in order to switch the amount of transmitted light, and has a function of changing the alignment state of the liquid crystal by applying a voltage. Depending on the alignment state of the liquid crystal layer enclosed in the liquid crystal layer and the alignment state of the liquid crystal layer when a voltage is applied between the electrodes, there are various types such as twisted nematic (TN) mode and vertical alignment (VA) mode. is there. The polarizing plate of the present invention can be effectively applied to liquid crystal cells of various modes widely used in general liquid crystal display devices.

  The performance of the protective film or the optical compensation film laminated on the polarizing film can be appropriately selected according to the operation mode and characteristics of the liquid crystal cell.

  The backlight constituting the liquid crystal display device may also be one widely used for general liquid crystal display devices. For example, a direct-type backlight that is composed of a diffuser plate and a light source disposed behind the diffuser plate, and that diffuses the light from the light source uniformly with the diffuser plate and emits it to the front side, or a light guide A sidelight type that is composed of a light plate and a light source arranged on the side of the light plate, and once the light from the light source is taken into the light guide plate, the light is uniformly emitted to the front side. A backlight etc. can be mentioned. As a light source in the backlight, a cold cathode fluorescent lamp that emits white light using a fluorescent tube, a light emitting diode (LED), or the like can be employed.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further more concretely, this invention is not limited by these examples.

In the following examples, the thickness of the stretched polyethylene terephthalate film is indicated by the manufacturer's nominal value. The in-plane retardation value R ₀ and the Nz coefficient were measured with a retardation film / optical material inspection apparatus RETS (manufactured by Otsuka Electronics Co., Ltd.). Further, the thickness, the in-plane retardation value R ₀ and the thickness direction retardation value R _th of the optical compensation film made of a cyclic olefin-based resin are represented by manufacturer designation values. R ₀ and R _th of the optical compensation film made of the cyclic olefin resin are actually measured using a retardation film / optical material inspection apparatus RETS (manufactured by Otsuka Electronics Co., Ltd.), but almost the same values are obtained. .

<Example 1>
(A) Production of Polarizing Film A polyvinyl alcohol film having an average polymerization degree of about 2400 and a saponification degree of 99.9 mol% or more and a thickness of 75 μm was immersed in pure water at 30 ° C., and then the weight of iodine / potassium iodide / water. It was immersed at 30 ° C. in an aqueous solution having a ratio of 0.02 / 2/100. Then, it was immersed at 56.5 ° C. in an aqueous solution having a potassium iodide / boric acid / water weight ratio of 12/5/100. Subsequently, the film was washed with pure water at 8 ° C. and then dried at 65 ° C. to obtain a polarizing film in which iodine was adsorbed and oriented on polyvinyl alcohol. Stretching was mainly performed in the iodine staining and boric acid treatment steps, and the total stretching ratio was 5.3 times.

(B) Production of polarizing plate with adhesive After corona treatment is applied to the bonding surface of a stretched polyethylene terephthalate film (Nz coefficient: 1.0, R ₀ : 2160 nm) having a thickness of 38 μm, an alicyclic epoxy compound is contained. The solventless active energy ray-curable adhesive composition to be applied was applied at a thickness of 2 μm by a coating apparatus equipped with a chamber doctor. Further, after applying a corona treatment to a bonding surface of an optical compensation film (in-plane retardation value R ₀ : 63 nm, thickness direction retardation value R _th : 225 nm) made of a cyclic olefin resin having a thickness of 73 μm, The same adhesive composition was applied with a thickness of 2 μm using the same apparatus.

Next, the stretched polyethylene terephthalate film is immediately placed on one side of the polarizing film obtained in (a) above, the optical compensation film is placed on the other side, and each is bonded by a bonding roll through the coating surface of the adhesive composition. Pasted. At this time, the deviation between the transmission axis of the polarizing film and the slow axis of the stretched polyethylene terephthalate film was 0 degree. Thereafter, from the stretched polyethylene terephthalate film side of the laminate, a metal halide lamp was irradiated so that the integrated light amount at a wavelength of 320 to 400 nm was 600 mJ / cm ² , thereby curing the adhesive on both sides. Further, an acrylic pressure-sensitive adhesive layer (with a separate film) having a thickness of 25 μm was provided on the outer surface of the optical compensation film of the obtained polarizing plate.

(C) Production of liquid crystal display device The light emitting side polarizing plate was peeled off from the liquid crystal panel of the vertical alignment mode liquid crystal display device “BRAVIA” (diagonal dimension 40 inches = about 102 cm) manufactured by Sony Corporation. A commercially available polarizing plate (Sumikaran SRW842E-GL5, manufactured by Sumitomo Chemical Co., Ltd.) was attached to the adhesive layer side in the same axial direction as the original polarizing plate. In addition, the light incident side polarizing plate is also peeled, and instead of the polarizing plate with the pressure sensitive adhesive layer produced in the above (b), the pressure sensitive adhesive layer is peeled off in the same axial direction as the original polarizing plate. It stuck using. When the obtained liquid crystal display device was visually observed, the color unevenness (interference unevenness) in the oblique direction was small, and the visibility was good.

<Example 2>
Using a stretched polyethylene terephthalate film with an Nz coefficient of 1.4 and an in-plane retardation value R ₀ of 3360 nm, adhesive bonding is performed so that the deviation angle between the transmission axis of the polarizing film and the slow axis of the stretched polyethylene terephthalate film is 40 degrees. A polarizing plate was produced in the same manner as in (b) of Example 1 except that this was performed, and a liquid crystal display device was produced in the same manner as in (c) of Example 1. When the obtained liquid crystal display device was visually observed, the color unevenness (interference unevenness) in the oblique direction was small, and the visibility was good.

<Example 3>
Using a stretched polyethylene terephthalate film with an Nz coefficient of 1.8 and an in-plane retardation value R ₀ of 3950 nm, adhesive bonding is performed so that the deviation angle between the transmission axis of the polarizing film and the slow axis of the stretched polyethylene terephthalate film is 40 degrees. A polarizing plate was produced in the same manner as in Example 1 (b) except for the above, and a liquid crystal display device was produced in the same manner as in Example 1 (c). When the obtained liquid crystal display device was visually observed, the color unevenness (interference unevenness) in the oblique direction was relatively small, and the visibility was relatively good.

<Example 4>
Using a stretched polyethylene terephthalate film with an Nz coefficient of 1.4 and an in-plane retardation value R ₀ of 1600 nm, adhesive bonding is performed so that the misalignment angle between the transmission axis of the polarizing film and the slow axis of the stretched polyethylene terephthalate film is 40 degrees. A polarizing plate was produced in the same manner as in Example 1 (b) except for the above, and a liquid crystal display device was produced in the same manner as in Example 1 (c). When the obtained liquid crystal display device was visually observed, although the color unevenness (interference unevenness) in the oblique direction was slightly stronger than that in Example 2, it was relatively small and the visibility was relatively good. .

<Example 5>
Using a stretched polyethylene terephthalate film with an Nz coefficient of 1.4 and an in-plane retardation value R ₀ of 800 nm, adhesive bonding is performed so that the deviation angle between the transmission axis of the polarizing film and the slow axis of the stretched polyethylene terephthalate film is 40 degrees. A polarizing plate was produced in the same manner as in (b) of Example 1 except that this was performed, and a liquid crystal display device was produced in the same manner as in (c) of Example 1. When the obtained liquid crystal display device was visually observed, the color unevenness (interference unevenness) in the oblique direction was small, and the visibility was good.

<Comparative Example 1>
Using a stretched polyethylene terephthalate film with an Nz coefficient of 3.0 and an in-plane retardation value R ₀ of 2300 nm, adhesive bonding is performed so that the deviation angle between the transmission axis of the polarizing film and the slow axis of the stretched polyethylene terephthalate film is 40 degrees. A polarizing plate was produced in the same manner as in Example 1 (b) except for the above, and a liquid crystal display device was produced in the same manner as in Example 1 (c). When the obtained liquid crystal display device was visually observed, the color unevenness (interference unevenness) in the oblique direction was large, and the visibility was poor.

  For each example, the optical properties and test results of the stretched polyethylene terephthalate film in the polarizing plate are summarized in Table 1.

  As shown in Table 1, for Examples 1 to 5 in which the Nz coefficient of the stretched polyethylene terephthalate film in the polarizing plate is less than 2.0, there is little color unevenness in the liquid crystal display device on which the polarizing plate is mounted, and visibility is improved. Excellent effect was observed. On the other hand, about the comparative example 1 whose Nz coefficient is 2.0 or more, the color nonuniformity was strong and it was inferior to visibility.

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

Claims (8)

A polarizing film comprising a polyvinyl alcohol resin;
A stretched polyethylene terephthalate film laminated on one side of the polarizing film via a first adhesive layer,
The oriented polyethylene terephthalate film, a slow axis direction of the in-plane refractive index n _x, the refractive index in a direction perpendicular to the slow axis in the plane n _y, the refractive index in the thickness direction is taken as n _{z , (n x -n z) /} (n x -n y) in a the Nz coefficient of 1.8 or less represented, and the oriented polyethylene terephthalate film, in-plane retardation value is 800~1200nm Alternatively, a polarizing plate having a value of 2000 to 3950 nm.   The polarizing plate according to claim 1, wherein the first adhesive layer is composed of a cured product layer of an active energy ray-curable composition containing an alicyclic epoxy compound.   The protective film or optical compensation film laminated | stacked through the 2nd adhesive bond layer on the surface on the opposite side to the surface where the said extending | stretching polyethylene terephthalate film in the said polarizing film is laminated | stacked is Claim 1 or 2. Polarizing plate.   The protective film or the optical compensation film is a transparent resin film selected from a cyclic olefin resin film, a cellulose resin film, a polycarbonate resin film, a chain olefin resin film, a polyester resin film, and an acrylic resin film. The polarizing plate of Claim 3 comprised. The polarizing plate according to claim 3 or 4, wherein the second adhesive layer is composed of a cured product layer having the same composition as the active energy ray- curable composition.   The polarizing plate according to any one of claims 3 to 5, further comprising an adhesive layer laminated on a surface of the protective film or the optical compensation film opposite to the surface on which the polarizing film is laminated.   The stretched polyethylene terephthalate film includes at least one layer selected from an antiglare layer, a hard coat layer, an antireflection layer, and an antistatic layer, which is laminated on a surface opposite to the surface on which the polarizing film is laminated. The polarizing plate in any one of Claims 1-6. The polarizing plate according to claim 6 is bonded to the liquid crystal cell via the pressure-sensitive adhesive layer , or the polarizing plate according to claim 7 is bonded to the liquid crystal cell via the pressure-sensitive adhesive layer. A liquid crystal display device including a liquid crystal panel.