JP6794181B2 - Polarizer - Google Patents

Description

The present invention relates to a polarizing plate.

As a method for manufacturing a polarizing plate used in a liquid crystal display device and an organic EL display device, a polarizing element obtained by stretching and dyeing a polyvinyl alcohol-based resin film is used as a film constituting a resin layer such as a retardation layer or a protective layer. A method of attaching to a polarizing plate is known. Further, as another method for producing a polarizing plate, a method has been proposed in which a polyvinyl alcohol-based resin layer is formed on a resin base material, and the laminate is stretched and dyed to use the polyvinyl alcohol-based resin layer as a polarizer. There is.

As described above, the polarizer can be used in a state of being laminated on a resin layer such as a retardation layer or a protective layer. Therefore, it is required that the polarizing element and the resin layer have sufficient adhesion so that the polarizing element does not peel off from the resin layer when the polarizing plate is used.

Patent Document 1 describes a resin in order to ensure sufficient adhesion between the resin base material and the polyvinyl alcohol-based resin layer in a manufacturing method for obtaining a polarizing plate from a laminate of the resin base material and the polyvinyl alcohol-based resin layer. It has been proposed that the base material and the polyvinyl alcohol-based resin layer are laminated via an easy-adhesion layer containing a polyvinyl alcohol-based material.

Japanese Patent No. 4950357

However, the polarizing plate manufactured by the method of Patent Document 1 has insufficient adhesion between the polarizer and the resin layer (resin base material).

The present invention has been made in view of the above problems, and an object of the present invention is to provide a polarizing plate having excellent adhesion between a resin layer and a polarizer and capable of suppressing the occurrence of cracks in the polarizer. There is.

The polarizing plate of the present invention has a resin layer and a polarizing element, and the resin layer and the polarizing element are laminated via an easy-adhesion layer, and the storage elastic modulus of the easy-adhesion layer at 85 ° C. It is 1.0 × 10 ⁶ Pa to 1.0 × 10 ⁷ Pa.
In one embodiment, the easy-adhesion layer has a storage elastic modulus of 1.0 × 10 ⁶ Pa to 1.0 × 10 at 85 ° C. after being heated at 80 ° C. for 500 hours in the presence of a cross-linking agent. It is ⁷ Pa.
In one embodiment, the easy-adhesive layer contains a polyolefin-based component and a polyvinyl alcohol-based component.
In one embodiment, the mass ratio of the polyolefin-based component to the polyvinyl alcohol-based component is 98: 2 to 90:10.
In one embodiment, the thickness of the easy-adhesion layer is 500 nm to 1 μm.
In one embodiment, the easy-adhesive layer and the polarizer are bonded to each other via an adhesive containing a polyvinyl alcohol-based resin.
In one embodiment, the resin layer is a retardation layer having an in-plane retardation.
In one embodiment, the in-plane retardation Re (550) of the retardation layer is 100 nm to 180 nm, and the relationship of Re (450) <Re (550) is satisfied.
In one embodiment, the angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer is 38 ° to 52 °.
In one embodiment, the resin layer is a protective layer that is optically isotropic.

According to the present invention, there is provided a polarizing plate that has excellent adhesion between the resin layer and the polarizer and can suppress the occurrence of cracks in the polarizer.

It is sectional drawing of the polarizing plate which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

(Definition of terms and symbols)
Definitions of terms and symbols in the present specification are as follows.
(1) Refractive index (nx, ny, nz)
"Nx" is the refractive index in the direction in which the in-plane refractive index is maximized (that is, the slow-phase axis direction), and "ny" is the in-plane direction orthogonal to the slow-phase axis (that is, the phase-advancing axis direction). Is the refractive index of, and "nz" is the refractive index in the thickness direction.
(2) In-plane phase difference (Re)
“Re (λ)” is an in-plane phase difference measured with light having a wavelength of λ nm at 23 ° C. Re (λ) is obtained by the formula: Re = (nx−ny) × d, where d (nm) is the thickness of the layer (film). For example, "Re (550)" is an in-plane phase difference measured with light having a wavelength of 550 nm at 23 ° C.

A. Polarizing plate The polarizing plate of the present invention has a resin layer and a polarizing element, and the resin layer and the polarizing element are bonded to each other via an easily adhesive layer. Polarizer is storage modulus at 85 ° C. of the adhesive layer is 1.0 × ¹⁰ 6 Pa or more. As a result, it is possible to obtain a polarizing plate that has excellent adhesion between the resin layer and the polarizer and can suppress the occurrence of cracks in the polarizer.

In one embodiment of the present invention, the resin layer is a retardation layer having an in-plane retardation. In another embodiment of the present invention, the resin layer may be a polarizing element protective layer (a protective film or an inner protective layer described later). Hereinafter, a polarizing plate in which the resin layer is a retardation layer will be mainly described.

FIG. 1 is a cross-sectional view of a polarizing plate according to one embodiment of the present invention. As shown in FIG. 1, the polarizing plate 10 has a retardation layer 3 as a resin layer, and the retardation layer 3 and the polarizer 1 are laminated via an easy-adhesion layer 2. Further, the polarizing plate 10 may have a protective film (not shown) on the side of the polarizing element 1 opposite to the retardation layer 3.

B. Polarizer As the polarizer 1, any suitable polarizer can be adopted. For example, the resin film forming the polarizer may be a single-layer resin film or a laminated body having two or more layers.

Specific examples of the polarizer composed of a single-layer resin film include a hydrophilic polymer film such as a polyvinyl alcohol (PVA) -based film, a partially formalized PVA-based film, and an ethylene / vinyl acetate copolymer system partially saponified film. Examples thereof include those which have been dyed and stretched with a bicolor substance such as iodine or a bicolor dye, and polyene-based oriented films such as a dehydrated product of PVA and a dehydrogenated product of polyvinyl chloride. Preferably, since the PVA-based film is excellent in optical characteristics, a polarizer obtained by dyeing a PVA-based film with iodine and uniaxially stretching it is used.

The dyeing with iodine is performed, for example, by immersing a PVA-based film in an aqueous iodine solution. The draw ratio of the uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the dyeing treatment or while dyeing. Moreover, you may dye after stretching. If necessary, the PVA-based film is subjected to a swelling treatment, a cross-linking treatment, a washing treatment, a drying treatment and the like. For example, by immersing the PVA-based film in water and washing it with water before dyeing, it is possible not only to clean the dirt on the surface of the PVA-based film and the blocking inhibitor, but also to swell the PVA-based film to prevent uneven dyeing. Can be prevented.

Specific examples of the polarizer obtained by using the laminate include a laminate of a resin base material and a PVA-based resin layer (PVA-based resin film) laminated on the resin base material, or a resin base material and the resin. Examples thereof include a polarizer obtained by using a laminate with a PVA-based resin layer coated and formed on a base material. The polarizer obtained by using the laminate of the resin base material and the PVA-based resin layer coated and formed on the resin base material is, for example, a resin base material obtained by applying a PVA-based resin solution to the resin base material and drying it. It is produced by forming a PVA-based resin layer on the PVA-based resin layer to obtain a laminate of a resin base material and a PVA-based resin layer; stretching and dyeing the laminate to make the PVA-based resin layer a polarizer. obtain. In the present embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution for stretching. Further, stretching may further include, if necessary, stretching the laminate in the air at a high temperature (eg, 95 ° C. or higher) prior to stretching in boric acid aqueous solution. The obtained resin base material / polarizer laminate may be used as it is (that is, the resin base material may be used as an inner protective layer provided between the retardation layer and the polarizer), or the resin base material / polarizing element may be used as it is. The resin base material (resin layer) may be peeled off from the laminated body of the child, and an arbitrary appropriate protective layer according to the purpose may be laminated on the peeled surface as an inner protective layer. Details of the method for producing such a polarizer are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580. The entire description of the publication is incorporated herein by reference. When the resin base material is used as an inner protective layer provided between the retardation layer and the polarizer, an easy-adhesion layer may be provided between the resin base material and the PVA-based resin layer. Further, when the resin base material is peeled off and an arbitrary appropriate protective layer according to the purpose is laminated as the inner protective layer on the peeled surface, an easy-adhesion layer may be provided between the inner protective layer and the polarizer. ..

The thickness of the polarizer can be appropriately designed according to the purpose and application, and is preferably 3 μm to 25 μm.

The polarizer preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The simple substance transmittance of the polarizer is preferably 42.0% to 46.0%, more preferably 44.5% to 46.0%. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and further preferably 99.9% or more.

C. Phase Difference Layer The retardation layer 3 may be composed of a retardation film having any suitable optical property and / or mechanical property depending on the purpose. The retardation layer 3 typically has a slow phase axis. In one embodiment, the angle θ formed by the slow axis of the retardation layer 3 and the absorption axis of the polarizer 1 is preferably 38 ° to 52 °, more preferably 42 ° to 48 °. More preferably, it is about 45 °. When the angle θ is in such a range, a polarizing plate 10 having extremely excellent circular polarization characteristics can be obtained by using the retardation layer 3 as a λ / 4 plate.

The retardation layer 3 preferably has a refractive index characteristic of nx> ny ≧ nz. The retardation layer 3 is typically provided to impart antireflection characteristics to the polarizing plate, and can function as a λ / 4 plate in one embodiment. In this case, the in-plane retardation Re (550) of the retardation layer 3 is preferably 80 nm to 200 nm, more preferably 100 nm to 180 nm, and even more preferably 110 nm to 170 nm. Here, "ny = nz" includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, ny <nz may be satisfied as long as the effect of the present invention is not impaired.

The birefringence Δn _xy of the retardation layer 3 is, for example, 0.0025 or more, preferably 0.0028 or more. On the other hand, the upper limit of the birefringence Δn _xy is, for example, 0.0060, preferably 0.0050. By optimizing the birefringence in such a range, a thin retardation layer 3 having desired optical characteristics can be obtained.

The Nz coefficient of the retardation layer 3 is preferably 0.9 to 3, more preferably 0.9 to 2.5, still more preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3. is there. By satisfying such a relationship, a very excellent reflected hue can be achieved when the obtained polarizing plate is used in an image display device.

The retardation layer 3 may exhibit a reverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light, and exhibits a positive wavelength dispersion characteristic in which the retardation value decreases according to the wavelength of the measurement light. Alternatively, it may exhibit a flat wavelength dispersion characteristic in which the phase difference value hardly changes depending on the wavelength of the measurement light. In one embodiment, the retardation layer 3 exhibits inverse dispersion wavelength characteristics. In this case, the retardation layer 3 satisfies the relationship of Re (450) <Re (550), and Re (450) / Re (550) of the retardation layer 3 is preferably 0.8 or more and less than 1, and more. It is preferably 0.8 or more and 0.95 or less. With such a configuration, very excellent antireflection characteristics can be realized. In another embodiment, the retardation layer 3 exhibits flat wavelength dispersion characteristics. In this case, Re (450) / Re (550) of the retardation layer 3 is preferably 0.99 to 1.03, and Re (650) / Re (550) is preferably 0.98 to 1.02. is there. In this case, the retardation layer 3 may have a laminated structure. Specifically, the retardation film that functions as a λ / 2 plate and the retardation film that functions as a λ / 4 plate are arranged at a predetermined axial angle (for example, 50 ° to 70 °, preferably about 60 °). As a result, it is possible to obtain characteristics close to the ideal inverse wavelength dispersion characteristics, and as a result, it is possible to realize extremely excellent antireflection characteristics.

The retardation layer 3 has a water absorption rate of 3% or less, preferably 2.5% or less, and more preferably 2% or less. By satisfying such a water absorption rate, it is possible to suppress a change in display characteristics with time. The water absorption rate can be determined in accordance with JIS K 7209.

In the retardation layer 3, the absolute value of the photoelastic coefficient is preferably 2 × 10 ^-11 m ² / N or less, more preferably 2.0 × 10 ^-13 m ² / N to 1.6 × 10 ^-11 m ^2. Contains / N resin. When the absolute value of the photoelastic coefficient is in such a range, the phase difference change is unlikely to occur when a shrinkage stress during heating occurs. As a result, thermal unevenness of the obtained image display device can be satisfactorily prevented.

The thickness of the retardation layer 3 is, for example, 70 μm or less, preferably 40 μm to 60 μm. With such a thickness, appropriate mechanical strength can be imparted as a protective layer for the polarizer.

The retardation layer 3 may be made of any suitable resin film that can satisfy the above characteristics. Typical examples of such resins are cyclic olefin resins, polycarbonate resins, cellulose resins, polyester resins, polyvinyl alcohol resins, polyamide resins, polyimide resins, polyether resins, polystyrene resins, and acrylics. Examples include based resins. When the retardation layer 3 is made of a resin film exhibiting an inverse dispersion wavelength characteristic, a polycarbonate resin can be preferably used.

As the polycarbonate resin, any suitable polycarbonate resin can be used as long as the effects of the present invention can be obtained. Preferably, the polycarbonate resin comprises a structural unit derived from a fluorene dihydroxy compound, a structural unit derived from an isosorbide dihydroxy compound, an alicyclic diol, an alicyclic dimethanol, di, tri or polyethylene glycol, and an alkylene. Includes structural units derived from at least one dihydroxy compound selected from the group consisting of glycols or spiroglycols. Preferably, the polycarbonate resin is derived from a structural unit derived from a fluorene dihydroxy compound, a structural unit derived from an isosorbide dihydroxy compound, a structural unit derived from an alicyclic dimethanol and / or di, tri or polyethylene glycol. Includes structural units; more preferably structural units derived from fluorene-based dihydroxy compounds, structural units derived from isosorbide-based dihydroxy compounds, and structural units derived from di, tri or polyethylene glycol. The polycarbonate resin may contain structural units derived from other dihydroxy compounds, if desired. Details of the polycarbonate resin that can be suitably used in the present invention are described in, for example, JP-A-2014-10291 and JP-A-2014-26266, and the description is incorporated herein by reference. To.

（上記一般式（１）中、Ｒ_１〜Ｒ_４はそれぞれ独立に、水素原子、置換若しくは無置換の炭素数１〜炭素数２０のアルキル基、置換若しくは無置換の炭素数６〜炭素数２０のシクロアルキル基、または、置換若しくは無置換の炭素数６〜炭素数２０のアリール基を表し、Ｘは置換若しくは無置換の炭素数２〜炭素数１０のアルキレン基、置換若しくは無置換の炭素数６〜炭素数２０のシクロアルキレン基、または、置換若しくは無置換の炭素数６〜炭素数２０のアリーレン基を表し、ｍ及びｎはそれぞれ独立に０〜５の整数である。） In one embodiment, a polycarbonate resin containing a unit structure derived from a dihydroxy compound represented by the following general formula (1) can be used.

(In the above general formula (1), R _{1 to} R ₄ are independently hydrogen atoms, substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, and substituted or unsubstituted alkyl groups having 6 to 20 carbon atoms. Represents a cycloalkyl group of, or an aryl group having 6 to 20 carbon atoms substituted or unsubstituted, and X is an alkylene group having 2 to 10 carbon atoms substituted or unsubstituted, and a substituted or unsubstituted carbon number. It represents a cycloalkylene group having 6 to 20 carbon atoms or an arylene group having 6 to 20 carbon atoms substituted or unsubstituted, and m and n are independently integers of 0 to 5).

Specific examples of the dihydroxy compound represented by the general formula (1) are 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, 9,9. -Bis (4-hydroxy-3-ethylphenyl) fluorene, 9,9-bis (4-hydroxy-3-n-propylphenyl) fluorene, 9,9-bis (4-hydroxy-3-isopropylphenyl) fluorene, 9,9-bis (4-hydroxy-3-n-butylphenyl) fluorene, 9,9-bis (4-hydroxy-3-sec-butylphenyl) fluorene, 9,9-bis (4-hydroxy-3-3) tert-butylphenyl) fluorene, 9,9-bis (4-hydroxy-3-cyclohexylphenyl) fluorene, 9,9-bis (4-hydroxy-3-phenylphenyl) fluorene, 9,9-bis (4- (4- (4-) 2-Hydroxyethoxy) phenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-methylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-isopropylphenyl) ) Fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-isobutylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-tert-butylphenyl) fluorene, 9 , 9-bis (4- (2-hydroxyethoxy) -3-cyclohexylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-phenylphenyl) fluorene, 9,9-bis (4) -(2-Hydroxyethoxy) -3,5-dimethylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-tert-butyl-6-methylphenyl) fluorene, 9,9-bis (4- (3-Hydroxy-2,2-dimethylpropoxy) phenyl) fluorene and the like can be mentioned.

In addition to the structural units derived from the dihydroxy compounds, the polycarbonate-based resin contains isosorbide, isomannide, isoidet, spiroglycol, dioxane glycol, diethylene glycol (DEG), triethylene glycol (TEG), polyethylene glycol (PEG), and bisphenols. It may contain a structural unit derived from a dihydroxy compound such as.

Details of the polycarbonate resin containing the structural unit derived from the dihydroxy compound are described in, for example, Japanese Patent No. 5204200, Japanese Patent Application Laid-Open No. 2012-67300, Japanese Patent No. 3325560, WO2014 / 061677 and the like. The description of the patent document is incorporated herein by reference.

（上記一般式（２）および上記一般式（３）中、Ｒ_５およびＲ_６はそれぞれ独立に、直接結合、置換若しくは無置換の炭素数１〜４のアルキレン基（好ましくは、主鎖上の炭素数が２〜３であるアルキレン基）である。Ｒ_７は、直接結合、置換若しくは無置換の炭素数１〜４のアルキレン基（好ましくは、主鎖上の炭素数が１〜２であるアルキレン基）である。Ｒ_８〜Ｒ_１３はそれぞれ独立に、水素原子、置換若しくは無置換の炭素数１〜１０（好ましくは１〜４、より好ましくは１〜２）のアルキル基、置換若しくは無置換の炭素数４〜１０（好ましくは４〜８、より好ましくは４〜７）のアリール基、置換若しくは無置換の炭素数１〜１０（好ましくは１〜４、より好ましくは１〜２）のアシル基、置換若しくは無置換の炭素数１〜１０（好ましくは１〜４、より好ましくは１〜２）のアルコキシ基、置換若しくは無置換の炭素数１〜１０（好ましくは１〜４、より好ましくは１〜２）のアリールオキシ基、置換若しくは無置換の炭素数１〜１０（好ましくは１〜４、より好ましくは１〜２）のアシルオキシ基、置換若しくは無置換のアミノ基、置換若しくは無置換の炭素数１〜１０（好ましくは１〜４）のビニル基、置換若しくは無置換の炭素数１〜１０（好ましくは１〜４）のエチニル基、置換基を有する硫黄原子、置換基を有するケイ素原子、ハロゲン原子、ニトロ基、またはシアノ基である。Ｒ_８〜Ｒ_１３のうち隣接する少なくとも２つの基が互いに結合して環を形成していてもよい。） In one embodiment, a polycarbonate resin containing an oligofluorene structural unit can be used. Examples of the polycarbonate-based resin containing an oligofluorene structural unit include a resin containing a structural unit represented by the following general formula (2) and / or a structural unit represented by the following general formula (3).

(In the above general formula (2) and the above general formula (3), R ₅ and R ₆ are independently bonded, substituted or unsubstituted alkylene groups having 1 to 4 carbon atoms (preferably on the main chain). An alkylene group having 2 to 3 carbon atoms). R ₇ is a directly bonded, substituted or unsubstituted alkylene group having 1 to 4 carbon atoms (preferably having 1 to 2 carbon atoms on the main chain). Alkylene groups). R _{8 to} R ₁₃ are independently hydrogen atoms, substituted or unsubstituted alkyl groups having 1 to 10 carbon atoms (preferably 1 to 4, more preferably 1 to 2), substituted or unsubstituted. Substituted aryl groups having 4 to 10 carbon atoms (preferably 4 to 8, more preferably 4 to 7), substituted or unsubstituted carbon atoms 1 to 10 (preferably 1 to 4, more preferably 1 to 2). Acrylic group, substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms (preferably 1 to 4, more preferably 1 to 2), substituted or unsubstituted carbon number 1 to 10 (preferably 1 to 4, more preferably). 1 to 2) aryloxy group, substituted or unsubstituted acyloxy group having 1 to 10 carbon atoms (preferably 1 to 4, more preferably 1-2), substituted or unsubstituted amino group, substituted or unsubstituted Vinyl group having 1 to 10 carbon atoms (preferably 1 to 4), ethynyl group having 1 to 10 (preferably 1 to 4) carbon atoms substituted or unsubstituted, sulfur atom having a substituent, silicon having a substituent. It is an atom, a halogen atom, a nitro group, or a cyano group. At least two adjacent groups of R _{8 to} R ₁₃ may be bonded to each other to form a ring.)

In one embodiment, the fluorene ring contained in the oligofluorene structural unit has a configuration in which all of R _{8 to} R ₁₃ are hydrogen atoms, or R ₈ and / or R ₁₃ is a halogen atom and an acyl group. , A nitro group, a cyano group, and a sulfo group, and R _{9 to} R ₁₂ are hydrogen atoms.

Details of the polycarbonate-based resin containing the oligofluorene structural unit are described in, for example, Japanese Patent Application Laid-Open No. 2015-212816. The description of the patent document is incorporated herein by reference.

The glass transition temperature of the polycarbonate resin is preferably 110 ° C. or higher and 150 ° C. or lower, more preferably 120 ° C. or higher and 140 ° C. or lower. If the glass transition temperature is excessively low, the heat resistance tends to deteriorate, which may cause dimensional changes after film molding, and may reduce the image quality of the obtained image display device. If the glass transition temperature is excessively high, the molding stability during film molding may be deteriorated, and the transparency of the film may be impaired. The glass transition temperature is determined according to JIS K 7121 (1987).

The molecular weight of the polycarbonate resin can be expressed by the reduced viscosity. The reduced viscosity is measured by using methylene chloride as a solvent, precisely adjusting the polycarbonate concentration to 0.6 g / dL, and using a Uberode viscosity tube at a temperature of 20.0 ° C. ± 0.1 ° C. The lower limit of the reduction viscosity is usually preferably 0.30 dL / g, more preferably 0.35 dL / g or more. The upper limit of the reduction viscosity is usually preferably 1.20 dL / g, more preferably 1.00 dL / g, and further preferably 0.80 dL / g. If the reduced viscosity is smaller than the above lower limit, there may be a problem that the mechanical strength of the molded product is reduced. On the other hand, if the reduced viscosity is larger than the above upper limit value, the fluidity at the time of molding is lowered, and there may be a problem that the productivity and the moldability are lowered.

A commercially available film may be used as the polycarbonate resin film. Specific examples of commercially available products include Teijin's product name "Pure Ace WR-S", "Pure Ace WR-W", "Pure Ace WR-M", and Nitto Denko's product name "NRF". Be done.

The retardation layer 3 can be obtained, for example, by stretching a film formed of the above-mentioned polycarbonate resin. As a method for forming a film from a polycarbonate-based resin, any suitable molding processing method can be adopted. Specific examples include a compression molding method, a transfer molding method, an injection molding method, an extrusion molding method, a blow molding method, a powder molding method, an FRP molding method, a cast coating method (for example, a casting method), a calendar molding method, and a hot press. Law etc. can be mentioned. Extrusion molding method or cast coating method is preferable. This is because the smoothness of the obtained film can be improved and good optical uniformity can be obtained. The molding conditions can be appropriately set according to the composition and type of the resin used, the characteristics desired for the retardation layer 3, and the like. As described above, since many film products of the polycarbonate resin are commercially available, the commercially available film may be subjected to the stretching treatment as it is.

The thickness of the resin film (unstretched film) can be set to an arbitrary appropriate value according to a desired thickness of the retardation layer, desired optical characteristics, stretching conditions described later, and the like. It is preferably 50 μm to 300 μm.

Any suitable stretching method and stretching conditions (for example, stretching temperature, stretching ratio, stretching direction) can be adopted for the stretching. Specifically, various stretching methods such as free-end stretching, fixed-end stretching, free-end contraction, and fixed-end contraction can be used alone or simultaneously or sequentially. As for the stretching direction, it can be performed in various directions and dimensions such as a length direction, a width direction, a thickness direction, and an oblique direction. The stretching temperature is preferably Tg-30 ° C to Tg + 60 ° C, more preferably Tg-10 ° C to Tg + 50 ° C, relative to the glass transition temperature (Tg) of the resin film.

By appropriately selecting the stretching method and stretching conditions, a retardation film having the desired optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient) can be obtained.

In one embodiment, the retardation film is made by uniaxially stretching or fixed end uniaxially stretching the resin film. Specific examples of the fixed-end uniaxial stretching include a method of stretching the resin film in the width direction (lateral direction) while running the resin film in the longitudinal direction. The draw ratio is preferably 1.1 times to 3.5 times.

In another embodiment, the retardation film can be made by continuously obliquely stretching a long resin film in the direction of the above angle θ with respect to the longitudinal direction. By adopting oblique stretching, a long stretched film having an orientation angle of an angle θ with respect to the longitudinal direction of the film (a slow axis in the direction of the angle θ) can be obtained, for example, when laminated with a polarizer. Roll-to-roll is possible, and the manufacturing process can be simplified. The angle θ can be an angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer in the polarizing plate. As described above, the angle θ is preferably 38 ° to 52 °, more preferably 42 ° to 48 °, and even more preferably about 45 °.

D. Easy-adhesion layer The easy-adhesion layer 2 is provided on the surface of the retardation layer 3 on the polarizer 1 side. The polarizing plate 10 is typically manufactured by bonding a retardation layer 3 having an easy-adhesion layer 2 formed on its surface and a polarizer via an adhesive.

As described above, the easy-adhesion layer 2 has a storage elastic modulus at 85 ° C. of 1.0 × 10 ⁶ Pa to 1.0 × 10 ⁷ Pa. Storage modulus at 85 ° C. of the adhesive layer 2 is preferably ^{2.0 × 10 6 Pa~7.0 × 10 6} Pa. As a result, the polarizing plate 10 can be obtained which has excellent adhesion between the retardation layer 3 and the polarizer 1 and can suppress the occurrence of cracks in the polarizer 1. Hereinafter, a specific description will be given. When the polarizing plate is used in a heating environment, the entire resin layer expands and the polarizer contracts, so that a shearing force may be applied to the easy-adhesion layer. If the storage elastic modulus at 85 ° C. of the adhesive layer is less than 1.0 × 10 6 ^Pa, soft and adhesive layer, a large deformation against stress applied. Therefore, when a shearing force is applied to the easy-adhesion layer, the adhesion at the interface with the polarizer 1 may be lowered, or the easy-adhesion layer may be coagulated and broken. In particular, when the easy-adhesion layer is peeled off at the interface with the polarizer, there may be a problem that the polarizer is exposed and cracks are generated in the polarizer. Furthermore, the storage elastic modulus at 85 ° C. of the adhesive layer is of less than 1.0 × 10 6 ^Pa, in some cases not be suppressed progression of minute cracks occurring in the polarizer. If the storage elastic modulus at 85 ° C. of the adhesive layer is more than 1.0 × 10 7 ^Pa, brittle adhesive layer, poor function of the stress relaxation due to the adhesive layer. Therefore, when a shearing force is applied to the easy-adhesion layer, the adhesion between the retardation layer and the polarizer is reduced, and as a result, the retardation layer may be broken and / or the easy-adhesion layer may be cohesive and broken. is there. On the other hand, since the storage elastic modulus of the easy-adhesion layer 2 at 85 ° C. is 1.0 × 10 ⁶ Pa to 1.0 × 10 ⁷ Pa, the retardation layer 3 and the polarizer 1 are separated from each other. It is possible to obtain a polarizing plate 10 having excellent adhesion and suppressing the fracture of the retardation layer 3 and / or the cohesive fracture of the easy-adhesion layer 2.

The storage elastic modulus of the easy-adhesion layer 2 at 85 ° C. after heating at 80 ° C. for 500 hours in the presence of a cross-linking agent is preferably 1.0 × 10 ⁶ Pa to 1.0 × 10 ⁷ Pa. Preferably, the easy-adhesion layer 2 has a storage elastic modulus of 1.0 × 10 ⁶ Pa to 1.0 × 10 ⁷ Pa at 85 ° C. before heating at 80 ° C. for 500 hours in the presence of a cross-linking agent, and the cross-linking agent. The storage elastic modulus at 85 ° C. after heating at 80 ° C. for 500 hours in the presence is 1.0 × 10 ⁶ Pa to 1.0 × 10 ⁷ Pa. In other words, preferably, the adhesive layer 2, the amount of change in storage modulus at 85 ° C. before and after 80 ° C. 500 hours of heating under crosslinking agent there is no more than 9.0 × ¹⁰ 6 Pa. When a conventional easy-adhesive layer composed of a polyvinyl alcohol-based component is used when the retardation layer 3 and the polarizer 1 are bonded to each other via an adhesive containing a polyvinyl alcohol-based resin as a main component, cross-linking contained in the adhesive is used. Due to the influence of the agent, cross-linking of the polyvinyl alcohol-based component contained in the easy-adhesive layer progresses, and as a result, the storage elasticity of the easy-adhesive layer increases with time, and the adhesion between the retardation layer and the polarizer decreases. obtain. In contrast, by the variation of storage modulus at 85 ° C. of about 80 ° C. 500 hours of heating under crosslinking agent exists using an easy-adhesion layer 2 is not more than 9.0 × 10 6 ^Pa, the retardation layer It is possible to reduce the increase in the storage elastic modulus of the easy-adhesion layer 2 with time after the 3 and the polarizer 1 are bonded together, and to suppress the decrease in the adhesion between the retardation layer 3 and the polarizer 1.

As the constituent material of the easy-adhesion layer 2, any suitable material having a storage elastic modulus at 85 ° C. within the above range can be adopted. The easy-adhesion layer 2 typically contains a polyolefin-based component and a polyvinyl alcohol-based component. In this case, the mass ratio of the polyolefin-based component to the polyvinyl alcohol-based component is preferably 86:14 to 99: 1, and more preferably 90: 10 to 98: 2. By adjusting the mass ratio of the polyolefin-based component and the polyvinyl alcohol-based component, the storage elastic modulus of the easy-adhesive layer 2 (substantially, the easy-adhesive composition forming the easy-adhesive layer 2) at 85 ° C. Can be controlled.

The easy-adhesive layer 2 is typically formed by applying an easy-adhesive composition to one side of the retardation layer 3 and drying it. Any suitable method may be adopted as the method for applying the constituent material of the easy-adhesion layer. For example, a bar coat method, a roll coat method, a gravure coat method, a rod coat method, a slot orifice coat method, a curtain coat method, a fountain coat method and the like can be mentioned. The drying temperature is typically 50 ° C. or higher, preferably 70 ° C. or higher, and more preferably 90 ° C. or higher. By setting the drying temperature in such a range, it is possible to provide a polarizing plate having excellent color resistance (particularly under high temperature and high humidity). The drying temperature is preferably 120 ° C. or lower, more preferably 100 ° C. or lower.

The thickness of the easy-adhesion layer 2 can be set to an arbitrary appropriate value. The thickness of the easy-adhesion layer 2 is preferably 500 nm to 1 μm, more preferably 700 nm to 800 nm. By setting in such a range, the adhesion to the polarizer 1 can be excellent, and the appearance of a phase difference in the easy-adhesion layer 2 can be suppressed.

E. Adhesive Layer The retardation layer 3 and the polarizer 1 are typically bonded via an adhesive layer formed on the easy-adhesive layer 2. The adhesive layer may be composed of any suitable adhesive. The thickness of the adhesive layer is preferably 10 nm to 300 nm, more preferably 10 nm to 200 nm, and particularly preferably 20 nm to 150 nm.

The adhesive preferably has transparency and optical isotropic properties. Any suitable form of the adhesive can be adopted. Specific examples include water-based adhesives, solvent-based adhesives, emulsion-based adhesives, solvent-free adhesives, active energy ray-curable adhesives, and thermosetting adhesives. Examples of the active energy ray-curable adhesive include an electron beam-curable adhesive, an ultraviolet-curable adhesive, and a visible light-curable adhesive. Aqueous adhesives can be preferably used.

Specific examples of the water-based adhesive include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based adhesives, water-based polyurethanes, and water-based polyesters. A polyvinyl alcohol-based adhesive such as polyvinyl alcohol or modified polyvinyl alcohol is preferable, and an adhesive containing polyvinyl alcohol having an acetoacetyl group as a main component is more preferable. Such adhesives are commercially available, and specific examples of the commercially available products include those manufactured by Nippon Synthetic Chemical Industry Co., Ltd. (trade name "Gosefima Z").

F. Protective film The protective film is formed of any suitable film that can be used as a protective film for the polarizer. Specific examples of the material that is the main component of the film include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and polysulfone-based. , Polystyrene-based, polycarbonate-based, polyolefin-based, (meth) acrylic-based, acetate-based transparent resins and the like. Further, thermosetting resins such as (meth) acrylic, urethane, (meth) acrylic urethane, epoxy, and silicone, or ultraviolet curable resins can also be mentioned. In addition to this, for example, glassy polymers such as siloxane-based polymers can also be mentioned. Further, the polymer film described in JP-A-2001-343529 (WO01 / 37007) can also be used. As the material of this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain. Can be used, and examples thereof include a resin composition having an alternating copolymer composed of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer. The polymer film can be, for example, an extruded product of the above resin composition.

The polarizing plate of the present invention is typically arranged on the visible side of the image display device, and the protective film is typically arranged on the visible side thereof. Therefore, the protective film may be subjected to surface treatment such as hard coating treatment, antireflection treatment, anti-sticking treatment, and anti-glare treatment, if necessary.

As the thickness of the protective film, any appropriate thickness can be adopted as long as the effects of the present invention can be obtained. The thickness of the protective film is, for example, 10 μm to 100 μm, preferably 30 μm to 90 μm. When the surface treatment is applied, the thickness of the protective film is the thickness including the thickness of the surface treatment layer.

G. Another protective layer Another protective layer (inner protective layer), which is arranged as needed, is also formed of any suitable film that can be used as a protective layer for the polarizer. The material that is the main component of the film is as described in Section F above with respect to the protective film. The thickness of the inner protective layer is, for example, 15 μm to 35 μm, preferably 20 μm to 30 μm. The inner protective layer is preferably optically isotropic. In the present specification, "optically isotropic" means that the in-plane retardation Re (550) is 0 nm to 10 nm and the thickness direction retardation Rth (550) is -10 nm to +10 nm. Say.

H. Others As described above, as one embodiment of the present invention, the polarizing plate 10 in which the resin layer is the retardation layer 3 has been described as an example, but the embodiment of the present invention is not limited thereto. That is, in the polarizing plate of another embodiment of the present invention, the resin layer can be an inner protective layer that can be provided on the retardation layer 3 side of the polarizer 1, and the polarizer 1 and the inner protective layer are easily adhered to each other. It may be adhered through. Further, in the polarizing plate of still another embodiment of the present invention, the resin layer can be a protective film that can be provided on the opposite side of the retarder 1 from the retardation layer 3, and the polarizer 1 and the protective film can be easily provided. It may be adhered via an adhesive layer.

I. Display device The polarizing plate according to the above items A to H can be applied to a display device such as a liquid crystal display device and an organic EL display device. Therefore, the present invention includes a display device using the above-mentioned polarizing plate. The display device according to the embodiment of the present invention includes a display element and the polarizing plates according to the above items A to H, which are arranged on the visual side of the display element. The polarizing plate is arranged so that the retardation layer is on the display element side.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

<Example 1>
1. 1. Fabrication of polarizer
A polymer film (manufactured by Kuraray Co., Ltd., trade name "VF-PE # 6000") containing a polyvinyl alcohol-based resin having a thickness of 60 μm as a main component is placed in 5 baths under the following conditions (1) to (5). The film was immersed while applying tension in the longitudinal direction, and stretched so that the final stretching ratio was 6.2 times the original length of the film. This stretched film was dried in an air circulation type drying oven at 40 degrees for 1 minute to prepare a polarizer.
<Conditions>
(1) Swelling bath: pure water at 30 degrees.
(2) Dyeing bath: An aqueous solution at 30 ° C. containing 0.035 parts by weight of iodine with respect to 100 parts by weight of water and 0.2 parts by weight of potassium iodide with respect to 100 parts by weight of water.
(3) First cross-linking bath: An aqueous solution at 40 ° C. containing 3% by weight of potassium iodide and 3% by weight of boric acid.
(4) Second cross-linking bath: A 60-degree aqueous solution containing 5% by weight of potassium iodide and 4% by weight of boric acid.
(5) Water washing bath: A 25 degree aqueous solution containing 3% by weight of potassium iodide.

2. 2. Fabrication of retardation film constituting the retardation layer (manufacture of polycarbonate resin film)
Bis [9- (2-phenoxycarbonylethyl) fluoren-9-yl] methane 38.06 parts by weight (0.059 mol) and isosorbide (manufactured by Rocket Foil, trade name "POLYSORB") 53.73 parts by weight (0) .368 mol), 1,4-cyclohexanedimethanol (cis, trans mixture, manufactured by SK Chemical Co., Ltd.) 9.64 parts by weight (0.067 mol), and diphenyl carbonate (manufactured by Mitsubishi Chemical Co., Ltd.) 81.28 parts by weight (0). .379 mol) and 3.83 × 10 ^-4 parts by weight (2.17 × 10 ^-6 mol) of calcium acetate monohydrate as a catalyst were put into the reaction vessel, and the inside of the reaction apparatus was replaced with reduced pressure nitrogen. The raw material was dissolved with stirring at 150 ° C. for about 10 minutes in a nitrogen atmosphere. As the first step of the reaction, the temperature was raised to 220 ° C. over 30 minutes, and the reaction was carried out at normal pressure for 60 minutes. Next, the pressure was reduced from normal pressure to 13.3 kPa over 90 minutes, held at 13.3 kPa for 30 minutes, and the generated phenol was extracted from the reaction system. Next, as the second step of the reaction, the temperature of the heat medium was raised to 240 ° C. over 15 minutes, the pressure was reduced to 0.10 kPa or less over 15 minutes, and the generated phenol was extracted from the reaction system. After reaching a predetermined stirring torque, the pressure was restored to normal pressure with nitrogen to stop the reaction, the produced polyester carbonate was extruded into water, and the strands were cut to obtain polycarbonate resin pellets.
(Making a retardation film)
A film composed of the above polycarbonate resin pellets is obliquely stretched to form a retardation film (thickness: 57 μm, photoelastic coefficient: 16 × ^10-12 Pa, Re (450): 120 nm, Re (550): 140 nm, Re ( 450) / Re (550): 0.86) was obtained. At that time, the stretching direction was set to 45 ° with respect to the longitudinal direction of the film. Further, the draw ratio was adjusted to 2 to 3 times so that the obtained retardation film exhibited a retardation of λ / 4. The stretching temperature was 148 ° C. (that is, Tg + 5 ° C. of the unstretched modified polycarbonate film).

3. 3. Formation of Easy Adhesive Layer 8 parts by weight of modified polyolefin resin (manufactured by Unitica Co., Ltd., trade name "Arrow Base SE-1030N") so that the mass ratio of the polyolefin-based component and the polyvinyl alcohol-based component is 98: 2. And 0.9 parts by weight of an aqueous solution of a polyvinyl alcohol-based resin (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosefimer Z200") and 27.0 parts by weight of pure water are mixed to form an easy-adhesive composition. I got something.

Using a dynamic viscoelasticity measuring device (manufactured by TA Instruments, trade name "RSA-G2", the load mode is set to the tensile mode, the temperature rise rate is 10 ° C./min, the frequency is 1 Hz, and the initial strain is 0.1%. obtained was measured storage modulus of the easy adhesive composition. storage modulus at 85 ° C. the obtained easy-adhesive composition was 2.4 × 10 6 ^Pa. in addition, under the cross-linking agent present The storage elastic modulus of the easy-adhesive composition at 85 ° C. after heating under the condition of 80 ° C. for 500 hours was 6.7 × 10 ⁶ Pa.

The obtained easy-adhesive composition was applied to one surface of the retardation film with a bar coater (# 6) so that the thickness after drying was 500 nm. Then, the polycarbonate-based resin film was put into a hot air dryer (90 ° C.) and the easy-adhesive composition was dried for about 5 minutes to form an easy-adhesive layer (thickness 500 nm) on one surface of the retardation film. ..

4. Fabrication of Polarizing Plate A water-soluble adhesive (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosefimer Z200") containing a polarizing element and a polyvinyl alcohol-based resin as a main component is applied to the easily adhesive layer forming surface of the retardation film. It was pasted together. The polarizer and the retardation film were bonded so that the angle formed by the absorption axis of the polarizer and the slow axis of the retardation film was 45 °. Next, a TAC film (manufactured by Dainippon Printing Co., Ltd., trade name "DSG-03", thickness 70 μm) is used as a protective film on the surface of the polarizing element opposite to the retardation layer, and the main component is a polyvinyl alcohol resin. A polarizing plate was obtained by laminating with a water-soluble adhesive (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosefimer Z200").

<Example 2>
Except for obtaining an easy-adhesive composition by mixing a modified polyolefin resin, a polyvinyl alcohol-based resin, and pure water so that the mass ratio of the polyolefin-based component and the polyvinyl alcohol-based component is 90:10. Made a polarizing plate in the same manner as in Example 1. Incidentally, the storage elastic modulus at 85 ° C. for easy adhesive composition obtained was 6.4 × 10 6 ^Pa. Further, the storage elastic modulus at 85 ° C. for easy adhesive composition after heating at the conditions of 80 ° C. 500 hours under crosslinking agent present was 8.2 × 10 6 ^Pa.

<Comparative example 1>
An easy-adhesive composition was obtained by mixing a modified polyolefin resin and pure water without using a polyvinyl alcohol resin so that the mass ratio of the polyolefin component and the polyvinyl alcohol component was 10: 0. A polarizing plate was produced in the same manner as in Example 1 except for the above. Incidentally, the storage elastic modulus at 85 ° C. for easy adhesive composition obtained was 8.8 × 10 5 ^Pa. Further, the storage elastic modulus at 85 ° C. for easy adhesive composition after heating at the conditions of 80 ° C. 500 hours under crosslinking agent present was 8.9 × 10 5 ^Pa.

<Comparative example 2>
Except for obtaining an easy-adhesive composition by mixing a modified polyolefin resin, a polyvinyl alcohol-based resin, and pure water so that the mass ratio of the polyolefin-based component and the polyvinyl alcohol-based component is 85:15. Made a polarizing plate in the same manner as in Example 1. Incidentally, the storage elastic modulus at 85 ° C. for easy adhesive composition obtained was 1.6 × 10 7 ^Pa. Further, the storage elastic modulus at 85 ° C. for easy adhesive composition after heating at the conditions of 80 ° C. 500 hours under crosslinking agent present was 8.2 × 10 8 ^Pa.

<Comparative example 3>
Except for obtaining an easy-adhesive composition by mixing a modified polyolefin resin, a polyvinyl alcohol-based resin, and pure water so that the mass ratio of the polyolefin-based component and the polyvinyl alcohol-based component is 70:30. Made a polarizing plate in the same manner as in Example 1. Incidentally, the storage elastic modulus at 85 ° C. for easy adhesive composition obtained was 4.5 × 10 7 ^Pa. Further, the storage elastic modulus at 85 ° C. for easy adhesive composition after heating at the conditions of 80 ° C. 500 hours under crosslinking agent present was 8.8 × 10 8 ^Pa.

<Comparative example 4>
An easy-adhesive composition was obtained by mixing a polyvinyl alcohol-based resin and pure water without using a modified polyolefin resin so that the mass ratio of the polyolefin-based component and the polyvinyl alcohol-based component was 0:10. A polarizing plate was produced in the same manner as in Example 1 except for the above. Incidentally, the storage elastic modulus at 85 ° C. for easy adhesive composition obtained was 2.3 × 10 8 ^Pa. The storage elastic modulus of the easy-adhesive composition at 85 ° C. after heating under the condition of 80 ° C. for 500 hours in the presence of a cross-linking agent was 9.5 × 10 ⁹ Pa.

<Comparative example 5>
10 parts by weight of water-based urethane resin (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name "Superflex 210") and 1.8 parts of oxazoline-based cross-linking agent (manufactured by Nippon Shokubai Co., Ltd., trade name "Epocross WS700") A polarizing plate was produced in the same manner as in Example 1 except that a parts by weight and 83 parts by weight of pure water were mixed to obtain an easy-adhesive composition. Storage modulus at 85 ° C. The obtained easy-adhesive composition was 2.0 × 10 8 ^Pa. Further, the storage elastic modulus at 85 ° C. for easy adhesive composition after heating at the conditions of 80 ° C. 500 hours was 4.1 × ¹⁰ 8 Pa.

(Evaluation)
The following evaluations were carried out for the above-mentioned Examples and Comparative Examples. The evaluation results are shown in Table 1.
(1) Initial adhesion test
An adhesive was applied to the retardation layer side of the polarizing plates obtained in the above Examples and Comparative Examples and bonded to a glass substrate to prepare a sample for measurement. A notch is made between the polarizer of this measurement sample and the easy-adhesion layer with a cutter knife, and the polarizer and the protective film are raised at an angle of 90 ° with respect to the surface of the retardation layer, and the peeling speed is 3000 mm. The force required for peeling at / min (peeling force: N / 15 mm) was measured using an angle-flexible adhesive / film peeling analyzer (manufactured by Kyowa Surface Chemical Co., Ltd., trade name "VPA-2"). In order to put it into practical use as a polarizing plate, the peeling force needs to be 1N / 15 mm or more.
(2) Peeling of Polarizer after Humidification Test After humidifying the polarizing plates obtained in the above Examples and Comparative Examples at 60 ° C. and 95% RH for 500 hours, the presence or absence of peeling of the polarizer was observed using an optical microscope. ..
(3) Cracks in the polarizer after the heat shock test After 300 cycles of holding the polarizing plates obtained in the above Examples and Comparative Examples in temperature environments of −40 ° C. and 85 ° C. for 30 minutes, respectively, The presence or absence of cracks in the polarizer was observed using an optical microscope.
(4) Peeling of Polarizer after Heating Test After heating the polarizing plates obtained in the above Examples and Comparative Examples at 80 ° C. for 500 hours, the presence or absence of peeling of the polarizing element was observed using an optical microscope.

The polarizing plate of the present invention is suitably used for, for example, an image display device. Specifically, LCD panels for LCD TVs, LCD displays, mobile phones, digital cameras, video cameras, portable game machines, car navigation systems, copiers, printers, fax machines, watches, microwave ovens, etc., and antireflection plates for organic EL devices. Etc., preferably used.

1 Polarizer 2 Easy-adhesion layer 3 Phase difference layer (resin layer)
10 Polarizing plate

Claims (6)

It has a resin layer and a polarizer,
The resin layer and the polarizer are laminated via an easy-adhesion layer.
The resin layer is a retardation layer having an in-plane retardation, which is made of a polycarbonate resin film.
The in-plane retardation Re (550) of the retardation layer is 100 nm to 180 nm, and the relationship of Re (450) <Re (550) is satisfied.
The polarizing plate having a storage elastic modulus of the easy-adhesion layer at 85 ° C. of 1.0 × 10 ⁶ Pa to 1.0 × 10 ⁷ Pa:
Here, Re (450) and Re (550) represent in-plane phase differences measured with light having wavelengths of 450 nm and 550 nm at 23 ° C., respectively. The polarizing plate according to claim 1, wherein the easily adhesive layer contains a polyolefin-based component and a polyvinyl alcohol-based component. The polarizing plate according to claim 2 , wherein the mass ratio of the polyolefin-based component to the polyvinyl alcohol-based component is 98: 2 to 90:10. The polarizing plate according to any one of claims 1 to 3 , wherein the thickness of the easy-adhesion layer is 500 nm to 1 μm. The polarizing plate according to any one of claims 1 to 4 , wherein the easy-adhesion layer and the polarizer are bonded to each other via an adhesive containing a polyvinyl alcohol-based resin. The polarizing plate according to any one of claims 1 to 5 , wherein the angle formed by the absorption axis of the polarizer and the slow axis of the retardation layer is 38 ° to 52 °.

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